JP5297696B2 - Newspaper and newspaper production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a newsprint having less white unevenness while having a coated layer, also having high opacity, hardly causing staining of blanket, clogging of a scraper and misregistration by paper powder, and exhibiting excellent printability. <P>SOLUTION: The newsprint is obtained by forming the coated layer by a coating agent consisting essentially of a pigment and an adhesive and colored with a dye at least on one surface of a base paper. The pigment is obtained using deinked froth discharged at a deinking step of a waste paper-treating process for producing a waste paper pulp as a main raw material, and through a dehydration step, a drying step, a burning step and a pulverizing step, wherein the pigment contains regenerated particle aggregates made in the burning step are contained. The whiteness of the base paper measured in accordance with JIS P 8148 is 52-60%, and L*, a* and b* of the newsprint surface calculated by CIE Lab color space provided by JIS P 8150 is 75.0 to 80.0, -3.50 to 0.50, and 3.50 to 7.50 respectively. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to newsprint. More specifically, it is lightweight, has a coating layer, has little white unevenness, has high opacity, is free from blanket stains due to paper dust, clogged swords and misregistration, and has excellent printability, such as high speed. The present invention relates to a newsprint that can be suitably used for offset printing such as offset color printing.

  As newsprint, base papers, mainly mechanical pulp and waste paper pulp, are used, but recently there has been a demand for paper weight reduction (low basis weight). The opacity after printing on the paper is also required.

  Therefore, in Patent Document 1, for example, a coating obtained by subjecting a carbide obtained by carbonizing a mixture of an organic substance and white inorganic particles to a whitening treatment, and having a regenerated pigment having a predetermined specific surface area and whiteness and an adhesive as main components. A coated paper for printing has been proposed in which a layer is provided on the surface of the base paper to improve the printing opacity of the paper.

  However, although the printing coated paper can surely improve the printing opacity, in the case of a paper having a low whiteness color tone such as newsprint paper, Not only is the appearance of the white color uneven on the surface, but it also looks bad, for example, when applied to satellite-type offset color printing machines, the dampening water used frequently during offset printing causes this to occur in the coating layer. There arises a problem that the dampening water is excessively impregnated and the paper strength is lowered.

In addition, in order to obtain newsprint paper with small white unevenness, a method of increasing the thickness of the coating layer provided on the outermost surface (increasing the coating amount) so as to conceal the color tone of the base paper is conceivable. The increase in layer thickness leads to a relative decrease in the basis weight of newsprint base paper, leading to a decrease in paper strength and paper breakage due to insufficient strength in high-speed rotary printing, and printing with an absorption drying type newspaper offset ink. In this case, the ink stays on the surface of the coating layer, resulting in problems such as printing stains and set-off.
JP 2003-119695 A

  The present invention has been made in view of the background art described above, has a coating layer, has little white unevenness, has high opacity, is free from blanket stains due to paper dust, clogged with a sword, and misregistration. An object is to provide newsprint with excellent aptitude.

The present invention
A method for producing newsprint , in which a coating layer is formed of a coating agent mainly composed of a pigment and an adhesive and colored with a dye on at least one side of a base paper,
As the pigment, the deinking floss discharged in the deinking process of the used paper processing process for producing the used paper pulp is used as a main raw material, through the dehydration process, the drying process, the combustion process and the pulverization process, without the carbonization process, At least the regenerated particle agglomerates that are aggregates in the combustion process are blended, the combustion process is at least two-stage combustion, and the furnace temperature (combustion temperature) of the first combustion furnace in the combustion process is 300 ° C. or more and 500 ° C. Is less than
The whiteness of the base paper measured in accordance with JIS P 8148 is 52-60%,
And whiteness of the base paper, coating layer surface, i.e. the whiteness difference of 1.1% or less of newsprint surface,
L *, a *, and b * of the paper surface calculated by the CIELab color space defined in JIS P 8150 are L * = 75.0 to 80.0,
a * = − 3.50 to 0.50,
b * = 3.50-7.50
The present invention relates to a newsprint paper manufacturing method , characterized by:

  According to the present invention, it is lightweight, has a coating layer, has little white unevenness, has high opacity, is free from blanket stains due to paper dust, clogged blades and misregistration, and has excellent printability. For example, newsprint that can be suitably used for offset printing such as high-speed offset color printing is provided.

(Embodiment)
In the newsprint of the present invention, at least one side of a base paper is composed of a pigment and an adhesive as main components, and a coating layer is formed of a coating agent colored with a dye, and at least a specific regenerated particle aggregate is blended as a pigment. The whiteness of the base paper is adjusted within a predetermined range, and L ^* , a ^* , b ^{* of} the paper surface calculated by the CIELab color space defined in JIS P 8150 is L ^* = 75.0 to 80.0,
a ^* = − 3.50 to 0.50,
b ^* = 3.50-7.50
It is a value within the predetermined range.

Here, in the present invention, L ^* , a ^* , b of the paper surface calculated by the CIELab color space defined in JIS P 8150 “Paper and paperboard—color (C / 2 °) measurement method—diffuse illumination method”. ^* Is defined in the CIE 1976 L ^* , a ^* , b ^* color space. The CIE 1976 L ^* , a ^* , b ^* color space is
L ^* = 116 (Y / Yn) ^1/3 -16
a ^* = 500 [(X / Xn) ¹ /3-(Y / Yn) ^1/3 ]
b ^* = 200 [(Y / Yn) ¹ /3-(Z / Zn) ^1/3 ]
Is a color space having a quantity L ^* a ^* b ^* determined by However, X / Xn, Y / Yn, and Z / Zn are greater than 0.008856, X, Y, and Z are tristimulus values of the object, and Xn, Yn, and Zn are tristimulus of the light source that illuminates the object color. The value is normalized to Yn = 100.

  First, the base paper used in the present invention will be described. There is no particular limitation on the type of pulp constituting the base paper, and pulp used for ordinary newsprint can be used as appropriate.

  Examples of the pulp include Stone Grand Pulp (SGP), Pressurized Stone Grand Pulp (PGW), Refiner Grand Pulp (RGP), Chemi Grand Pulp (CGP), Thermo Grand Pulp (TGP), Ground Wood Pulp (GP), Thermomechanical. Pulp (TMP), Chemi-thermomechanical pulp (CTMP), Refiner mechanical pulp (RMP) and other mechanical pulp; hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), conifer Chemical pulp such as unbleached kraft pulp (NUKP), hardwood semi-bleached kraft pulp (LSBKP), conifer semi-bleached kraft pulp (NSBKP), hardwood sulfite pulp, coniferous sulfite pulp, tea waste paper, craft envelope waste paper, magazine waste paper, newspaper waste Waste paper, office waste paper, top white paper, Kent waste paper, imitation waste paper, recycle waste paper pulp, disaggregation / deinking waste paper pulp, waste paper pulp such as disaggregation / deinking waste paper pulp, The pulp etc. which bleached these are mention | raise | lifted, 1 type (s) or 2 or more types can be selected suitably from these, and the ratio can be adjusted and used.

  Among the used paper pulp, the used newsprint pulp is recycled from newsprint recovered through an established route, and can be suitably used as a raw material pulp constituting the base paper. Pulp is generally deteriorated and shortened by repeated collection and reuse, and there is a risk of reducing the strength and opacity of newsprint. However, since the newsprint of the present invention has a specific coating layer on both sides of the base paper, even when used as needed newsprint paper pulp, improvement of opacity and maintenance of paper strength are realized at the same time. can do.

  The base paper used in the present invention is composed of, for example, pulp as described above. In addition to such pulp, for example, a papermaking chemical used for ordinary newsprint can be blended.

  Examples of the papermaking agent include fillers such as kaolin, calcium carbonate, talc, titanium dioxide, white carbon and urea formaldehyde resin; internal sizing agents such as water-soluble polymers and rosin emulsions; starches, plant gums, carboxymethyl cellulose And a paper strength enhancer such as polyacrylamide; a yield improver; a freeness improver, and the like. One or more of these can be selected as appropriate, and the blending amount can be adjusted and used.

  The method for producing the base paper used in the present invention is not particularly limited. For example, after adding a papermaking agent to the pulp, conditions such as a pH value are appropriately adjusted, and papermaking such as a long web papermaking machine or a gap former papermaking machine is performed. It is possible to adopt a method of making paper in a normal process using a machine.

  The whiteness of the base paper is 52% or more, preferably 53, as measured according to the method described in JIS P 8148: 2001 “Paper, Paperboard and Pulp-ISO Whiteness (Diffusion Blue Light Reflectance) Measurement Method”. % Or more and 60% or less, preferably 58% or less. In the present invention, the base paper has such a degree of whiteness that is required for general newsprint paper, and the whiteness of the base paper and the surface of the coating layer formed on the surface of the base paper, That is, the whiteness of the newsprint surface is leveled.

The basis weight of the base paper is not particularly limited, but it is considered that the basis weight measured in accordance with JIS P 8124 “Paper and paperboard—basis weight measurement method” of the target newspaper is 35 to 50 g / m ^2. And it is preferable to adjust so that the basic weight of a base paper may be about 30-47 g / m < ² > normally.

  Next, the coating layer formed on both surfaces of the base paper will be described. The coating layer is formed of a coating agent mainly composed of a pigment and an adhesive and colored with a dye, and at least a specific regenerated particle aggregate is blended as the pigment.

  Newspaper paper usually requires a reduction in slipperiness (providing anti-slip property) so that it does not collapse when stacked, from the viewpoint of workability during distribution and transportation, and contrary to the anti-slip property. When printing and folding, moderate slipperiness is required. For example, conventional paper with internal white carbon and paper with a coating layer containing white carbon on the surface, as evident from the fact that white carbon itself is used as an anti-slip agent, Therefore, it is easy to cause a fold failure such as clogging of the sword tip during folding with a rotary press.

  However, the regenerated particle agglomerate used in the present invention is preferably an agglomerate containing three components of calcium, silicon, and aluminum as its particle constituents as described later, and is a dye contained as a coating agent. Therefore, moderate slipperiness can be imparted to the obtained newsprint, and the conflicting effects such as anti-slipperiness required during distribution / conveyance and slipperiness required during printing / folding can be appropriately expressed. Thus, it is one of the major features of the present invention that at least such a regenerated particle aggregate is blended as a pigment which is the main component of the coating agent.

  The regenerated particle agglomerate is mainly composed of deinked floss discharged in the deinking process of the used paper processing process for producing used paper pulp, and is subjected to a dehydration process, a drying process, a combustion process, and a pulverization process in the combustion process. It is a collection.

  Since such regenerated particle aggregates can be recycled by burning deinked floss, there is no need to dispose of landfills as waste, reducing environmental impact and saving resources. It greatly contributes to. In addition, since the main raw material is deinking floss generated in the deinking process of the used paper processing process, it is inexpensive, the amount of use of new natural inorganic minerals can be suppressed, and the manufacturing cost can be sufficiently reduced. is there. Furthermore, by using such a regenerated particle aggregate, the yield of ash during papermaking is high, and unlike ordinary calcium carbonate, for example, it does not cause wear deterioration of papermaking equipment such as wire wear, and the resin component is further reduced. By adsorbing to the regenerated particle aggregate in a fine state, it is possible to prevent pitch troubles due to aggregation of the resin component, hardly cause soiling of the papermaking equipment, and to produce newsprint paper with low cost and high operability.

  In addition, when manufacturing the said regenerated particle aggregate, you may pass through the granulation process of a deinking floss, the classification process provided between each process, etc. so that it may mention later. In addition, it is desirable to provide various sensors in the production facility for the regenerated particle aggregate to control the state of the object to be processed and the equipment, the processing speed, and the like. Various flow paths such as a transfer flow path, a supply flow path, a delivery flow path, a circulation flow path, and a return flow path shown in the following specific description can be constituted by, for example, a pipe, a duct, or the like.

  The main raw material of the regenerated particle aggregate is, for example, deinking floss generated in a flotation process of a deinking process for producing deinked waste paper pulp from waste paper. In particular, deinking floss discharged in the recycling process of used paper is preferable because it is made of a material derived from papermaking raw materials and contains less impurities such as iron and other heavy metals. In the used paper recycling process, the used paper itself is selected in advance, so that the deinking floss has a stable inorganic composition over time, and the resulting recycled particle aggregate has a stable composition. These deinking froths contain, for example, calcium carbonate, kaolin, talc, titanium dioxide, silica, alumina and the like as inorganic substances. In addition, it is preferable that the ratio of the deinking froth in all the raw materials of the regenerated particle aggregate is 50% by mass or more, further 60% by mass or more as a solid content.

  Usually, the deinking floss is dehydrated by a dehydrating means such as a screen so that the water content is about 90 to 97% by mass, and further the water content is 50% by mass or less, further 25 by a dehydrating unit such as a screw press. It is preferable to dehydrate until it becomes -45 mass%, especially 30-40 mass%. If the moisture content exceeds 50% by mass, the drying energy cost in the next drying process may increase or the particle size after drying may vary, resulting in difficulty in uniform combustion. The processing temperature in one combustion furnace is lowered, energy loss during heating is increased, and uneven combustion of the raw material is likely to occur, which may make it difficult to promote uniform combustion. Furthermore, the moisture in the exhaust gas increases, which may result in a decrease in the efficiency of recombustion treatment for dioxin countermeasures and an increased load on the exhaust gas treatment facility. On the other hand, if the water content is dehydrated to less than 25% by mass, the dehydration equipment increases in size and the dehydration energy cost may increase.

  The obtained deinked deinking floss (dehydrated product) is dried in advance. As the drying means, known means such as hot air drying can be used, but it is possible to use the hot air drying means which can be loosened while drying the deinking floss and further can be classified by specific gravity. it can.

  Specific examples of the hot air drying means that can be suitably used are such that the dehydrated material has a volume average particle size of 4000 μm or less, more preferably 300 to 3000 μm, particularly 500 to 2000 μm, using a loosening facility such as an impeller. While loosening, hot air is blown by hot air blowing means provided below the impeller equipment, and hot air drying is performed. Of the deinked floss that has been loosened and dried, the deinked floss having a low specific gravity is discharged from the outlet provided in the upper part of the hot air drying means, whereby drying and classification can be performed. As a suitable means for classification of the dry deinking floss, a classification means using a cyclone can be adopted.

  The particle size distribution of the dried and literated deinking floss (dried product) is such that the particles having a particle size of 5000 μm or less are 70% by mass or more, further 72% by mass or more, particularly 80% by mass or more in the volume distribution of the particle diameter. It is particularly preferable to adjust to. As described above, when the dried product is produced so that the particles having a particle size of 5000 μm or less are 70% by mass or more, the quality of the obtained regenerated particle aggregate becomes more uniform, and the possibility of practical use is further increased. Can do.

  The temperature of the hot air when the hot air drying means is adopted is preferably adjusted appropriately in consideration of the moisture content of the dehydrated product to be used in the drying process and the moisture content of the intended dried product, but for example, 100 to 200 ° C. It is preferable to set the degree.

  Thus, it is preferable that the moisture content of the dried material which passed through the drying process is adjusted to about 2 to 20% by mass, and further to about 5 to 15% by mass. If the moisture content of the dried product is lower than 2% by mass, it may be overfired in the next combustion step. Conversely, if it is higher than 20% by mass, it is difficult to reliably perform combustion due to insufficient drying. There is a fear.

  Next, the deinked floss that has been dried and classified is sent to the combustion process. Combustion can be performed using a commonly used incinerator such as a rotary kiln, fluidized bed furnace, floating furnace, stoker furnace, etc., among which a method by indirect heating with a hot air furnace or an electric furnace is a combustion temperature control, This is particularly preferable because fine adjustment of the degree of combustion is easy. For example, in combustion using a rotary kiln, combustion by direct heating or combustion by indirect heating can be performed alone or in combination. For example, the primary combustion in the first combustion furnace is a direct heating kiln furnace, particularly an internal heat kiln furnace, the secondary combustion in the second combustion furnace is an indirect heating kiln furnace, particularly an external heat kiln furnace that can easily adjust the combustion temperature. Each method can be adopted.

  The combustion process may be one-stage combustion, but is preferably at least two-stage combustion, and more preferably at least two-stage combustion by continuous equipment. When the combustion process is at least two stages, it is difficult for uneven combustion to occur in the combustion due to the combustion of organic matter, and the combustion can proceed evenly. In particular, by making different physical means in the combustion process, it is possible to avoid uneven combustion and improve the combustion speed.

  The combustion temperature is such that ink pigments such as carbon black in the deinking floss, organic compounds such as fibers and polymers are burned, and the particles contain three components of calcium, silicon and aluminum. The temperature is not particularly limited as long as the temperature is sufficient and stable to form aggregated regenerated particles aggregated in the combustion process.

  When silica is contained in the deinking floss, the silica may react with calcium and aluminum to produce aluminum calcium silicate having high hardness. In order to prevent the production of such a substance having high hardness, for example, it is considered to burn at a temperature of 500 ° C. or less. However, under such conditions, it is difficult to completely burn the organic compound, and as a pigment Obtaining regenerated particle aggregates having useful levels of whiteness can be difficult.

  On the other hand, when the combustion temperature exceeds 1000 ° C., the decomposition and sintering of inorganic substances such as calcium carbonate, kaolin, talc, titanium dioxide, silica, alumina, etc. contained in the deinking floss progress and increase in hardness. There is a possibility that much energy and time are required to grind the regenerated particle aggregate to a desired particle size.

  Thus, since the combustion temperature has a great influence on the whiteness and hardness of the regenerated particle aggregate to be produced, the primary combustion is 500 to 650 ° C. and the secondary combustion is 550 to 750 ° C. The primary combustion is preferably performed at 530 to 630 ° C, and the secondary combustion is preferably performed at 600 to 730 ° C. When the primary combustion temperature is less than 500 ° C., the remaining amount of unburned matter is large and the aggregate formation of inorganic particles is insufficient. For example, the whiteness of the obtained regenerated particle aggregate may not be sufficiently improved. There is. On the other hand, when the primary combustion temperature exceeds 650 ° C., most of the calcium carbonate contained in the deinking floss is thermally decomposed, and it is difficult to use as a resource. There is a possibility that it will occur in many cases, and the resulting regenerated particle agglomerates will be melted by heat and may be extremely hard and the wire wear resistance may be reduced. On the other hand, when the secondary combustion temperature is less than 550 ° C., the organic matter may not be sufficiently burned or combustion unevenness may occur, and the whiteness of the resulting regenerated particle aggregate may not be improved. Conversely, when the secondary combustion temperature exceeds 750 ° C., the surface of the regenerated particle aggregate that has been combusted and aggregated is exposed to a high temperature, which may cause melting to form a very hard melt, or the surface of inorganic particles Oxygen is difficult to reach the inorganic particle core due to combustion due to higher temperatures of the particles, and there may be concerns about uneven combustion and occurrence of unburned sites. Moreover, by making the secondary combustion temperature 50 to 120 ° C. higher than the primary combustion temperature, it is possible to burn the unburned material while preventing overburning of the surface of the regenerated particle aggregate.

  Of course, the secondary combustion temperature may be the same as the primary combustion temperature. When the secondary combustion temperature is set to the same temperature as the primary combustion temperature, for example, when the temperature is set to 530 to 730 ° C., the combustion proceeds slowly, the unburned matter can be reduced, and the regenerated particle aggregate having sufficient whiteness is obtained. A collection can be obtained. In the present invention, the temperature difference between the primary combustion temperature and the secondary combustion temperature is based on the temperature of the upper end portion in the combustion furnace.

  In the combustion process, the oxygen concentration in the combustion process is 0.05% or more, further 0.1% or more by at least one of the means for blowing air into the process and the means for exhausting air from the process. It is preferable to adjust to 20% or less. In particular, the oxygen concentration in the combustion process is desirably adjusted to 0.2 to 20%, more preferably 1 to 15%, and particularly preferably 5 to 12% at the upper end of the first combustion furnace. It is desirable to adjust to 5 to 20%, more preferably 10 to 20%, particularly preferably 15 to 18% in the vicinity of the burner of the second combustion furnace. If the oxygen concentration at the upper end in the first combustion furnace is less than 0.2%, combustion does not proceed and not only uneven combustion proceeds, but also the combustion may require enormous time and energy costs. There is. On the other hand, if the oxygen concentration in the vicinity of the burner of the second combustion furnace exceeds 20%, it is easy to overheat, and the regenerated particle aggregates turn yellow due to overheating unevenness, and the regenerated particle aggregates frequently melt and decompose. Oxidation proceeds and it may be difficult to use as a pigment. In the present invention, the moisture content of the dried and classified deinked floss (dried material) supplied to the combustion process is preferably about 2 to 20% by mass, more preferably about 5 to 15% by mass. Therefore, if the oxygen concentration in the combustion process is set to 0.05 to 20%, combustion can proceed extremely efficiently, combustion can be performed within 90 minutes, and extremely high productivity is achieved. Can be obtained. For example, by setting the moisture content of the dried product to 10% by mass, combustion can be performed in about 60 minutes.

  In addition, oxygen in the combustion process is consumed by a burner or the like for burning, and the oxygen concentration in the combustion process is reduced, but the oxygen concentration is maintained by blowing or exhausting an oxygen-containing gas such as air. It is possible to adjust the temperature in the combustion process by blowing or exhausting oxygen-containing gas and burning the regenerated particle agglomerates evenly and uniformly. Can do.

  The residence time in the combustion process is not particularly limited, and may be adjusted so that sufficient combustion is performed according to the conditions such as the combustion temperature and the oxygen concentration in the combustion process. For example, in the first combustion furnace The residence time is 30 to 90 minutes, further 40 to 80 minutes, especially 50 to 70 minutes, and the residence time in the second combustion furnace is 10 to 60 minutes, more preferably 15 to 45 minutes, especially 20 It is preferable to adjust so that it may be for ~ 40 minutes.

  The combustion in the first combustion furnace is preferably performed so that the unburned rate is 5 to 30% by mass, further 8 to 25% by mass, and particularly 10 to 20% by mass. When the unburned rate after primary combustion is less than 5% by mass, over-burning of the particle surface during combustion occurs, the surface becomes hard, oxygen deficiency inside occurs, and the whiteness of the regenerated particle aggregate may be reduced. . On the other hand, if the unburned rate after primary combustion exceeds 30% by mass, the unburned portion remains after the subsequent burning and burning, the particles are hardened due to overburning due to the unburned portion, or the unburned portion is reduced. In order to prevent the particles from remaining, the surface of the particles is burnt and combusted until it is overfired, and the surface of the regenerated particle aggregate may be hardened.

  In addition, although the preferable conditions in a combustion process which can be employ | adopted in this invention are as above-mentioned, an even more suitable combustion condition etc. are demonstrated below.

  For example, in the case of burning papermaking sludge, (1) Japanese Patent Application Laid-Open No. 2003-119695 discloses an oxygen-deficient state in which oxygen is not present substantially in an oxygen concentration of 0.1% by volume or less in a furnace. Specifically, drying and carbonization in an indirect heating furnace (external heat combustion furnace), then deoxidizing carbon derived from organic matter contained in the carbide, specifically whitening in an indirect heating furnace A method of processing has been proposed. The publication also discloses the use of an internal heat rotary kiln furnace in the latter whitening treatment.

  On the other hand, (2) JP 2002-275785 also discloses the use of a rotary kiln furnace for recombustion after carbonization.

  Further, in (3) Japanese Patent No. 3808852, deinking sludge is used as a raw material sludge, and the drying process is performed, and the dried deinking sludge is supplied into the furnace from the upper part of the cyclone combustion furnace. A primary combustion process for obtaining a primary combustion product containing unburned matter by burning while swirling and lowering, and a mechanical combustion in communication with the cyclone type combustion furnace and receiving the primary combustion product containing unburned content from its lower end A secondary combustion process in which the heat of combustion in the primary combustion process is used to promote combustion until the predetermined whiteness is achieved while promoting contact with oxygen by vigorous stirring, and the white pigment or white filler from the deinking sludge. Manufacturing methods have been proposed.

  Also, (4) Japanese Patent Application Laid-Open No. 2004-176208 proposes a method of drying, carbonizing, and burning molded sludge in one rotary kiln furnace when producing filler from wastewater treatment sludge in the coated paper manufacturing process. Has been.

  The methods described in the above (1), (2) and (4) are not based on deinking floss separated from pulp fibers in the deinking process of the used paper processing facility for producing used paper pulp, Sludge is the main raw material, and the regenerated particles obtained are considered to be different from the regenerated particle aggregates used in the present invention.

  On the other hand, according to the method described in (3), regenerated particles substantially the same as the regenerated particle aggregate used in the present invention can be obtained. In this method, a cyclone fluidized combustion furnace is used, and a dried product is obtained. And then secondary combustion.

  When using a cyclonic fluidized combustion furnace in the combustion process, it is thought that it is derived from its own form, but in the cyclone type, raw materials and air of tens to hundreds of microns are generally supplied from the supply port as a swirling flow. The raw material is burned by being effectively mixed with air by the swirling action of air. Therefore, the fine particles contained in the raw material are discharged out of the system together with the exhaust gas, resulting in a decrease in product yield, and the burning time (heating time) of the deinking floss that is the main raw material is short, so unburned components are likely to occur. The quality, particularly the shape, of the finally obtained combustion product is not constant, and the whiteness of the combustion product may vary.

  Therefore, the first combustion furnace is provided for at least two stages of combustion processes, including a first combustion furnace, and a second combustion furnace that burns again the deinking floss burned in the first combustion furnace. In the above, for example, by performing the combustion treatment at a relatively low temperature of 300 ° C. or higher and lower than 500 ° C., excessive combustion does not occur, and a regenerated particle aggregate with more stable quality can be produced.

  Specifically, the raw material after dehydration is dried and burned in series, and the combustion time (residence time) in the first combustion furnace by internal heat exceeds 30 minutes and is 90 minutes or less, more preferably 40 to 80. Minutes, optimally 50-70 minutes. Further, the raw material after dehydration is dried and burned (primary combustion) by an internal heat (direct heating) kiln furnace in which the main body is placed horizontally and rotates around the central axis, and then combustion obtained from the first combustion furnace The product is combusted again (secondary combustion) in a second combustion furnace with external heat, and the combustion time (residence time) is 60 minutes or more, more preferably 60 to 240 minutes, particularly preferably 90 to 150 minutes, Optimally, it is desirable to be 120 to 150 minutes. Further, it is more preferable to perform secondary combustion in an external heat (indirect heating) kiln furnace in which the main body is placed horizontally and rotates around the central axis, particularly an external heat electric furnace in which the combustion temperature can be easily adjusted.

  Further, in the method for producing a regenerated particle aggregate described later with reference to the drawings, an internal heat kiln furnace is exemplified as the first combustion furnace, and an external heat kiln furnace is exemplified as the second combustion furnace. A known combustion furnace can be used. Moreover, it is not limited to a kiln furnace, Well-known combustion furnaces, such as a fluidized bed furnace, a stalker furnace, a cyclone furnace, a semi-dry distillation / negative pressure combustion type furnace, can be used. In the present invention, any known combustion furnace can be used as long as it is at least a two-stage combustion furnace in which the first primary combustion is performed in the first combustion furnace using internal heat and the subsequent secondary combustion is performed in the second combustion furnace using external heat. These combustion furnaces can also be suitably used. Further, as the second combustion furnace using external heat, a known combustion method using an indirect heating type combustion furnace using heavy oil or the like as a heat source may be employed.

  In the internal heat kiln furnace that is preferably used as the first combustion furnace, drying and combustion can be performed in one furnace, and drying and combustion proceed slowly and stably from the supply port to the discharge port, and Combustion is prevented from being pulverized. Further, when combustion is performed in an external heat kiln furnace that is preferably used as the second combustion furnace, the combusted material after the primary combustion is subjected to secondary combustion with a predetermined residence time from the end portion thereof, and then from the discharge port of the other end portion. Further, since uniform heat is applied to the combustion product by the external heat, the combustion is performed uniformly and there is no variation in the combustion. Furthermore, since the combustion product is gently stirred by friction caused by rotation of the inner wall of the kiln furnace, pulverization is unlikely to occur. As a result, the quality and shape of the final combustion product becomes more stable.

  For example, as described above, in the first combustion furnace, in order to efficiently burn fine fibers in the raw material, latex that is an organic polymer compound frequently used for coated paper, ink components applied by printing, etc., A method of dehydrating and drying the rate to less than 40% and combusting at a high temperature can be adopted. In the first combustion furnace, for example, by performing a heating operation at a relatively low temperature of 300 ° C. or more and less than 500 ° C., the raw material The organic matter contained in is converted into combustion gas, and the combustion gas is burned (oxidized), whereby the quality stability and whiteness of the obtained regenerated particle aggregate are further improved.

  In this way, drying and combustion in the combustion process are preferably performed in an internal heat kiln furnace and an external heat kiln furnace in at least a two-stage combustion furnace, so that the regenerated particle agglomeration having more uniform and excellent stability can be obtained. A collection can be obtained.

  An internal heat kiln furnace or an external heat kiln furnace used as a suitable combustion furnace can lift and agitate the combusted material without slipping by making the internal refractory into a hexagonal or octagonal shape instead of a circumferential shape. However, in reality, the kiln furnace has a cylindrical shape, and it is optimal to provide a lifter for stirring the combusted material in terms of uniform combustion of the raw materials and uniform quality. This is also considered to be related to intentionally burning the entire raw material slowly at a low temperature in the first combustion furnace.

  Further, a combustion furnace for obtaining a more preferable regenerated particle aggregate will be described below.

  Conventionally used combustion furnaces can be broadly classified into four types: stalker furnaces (fixed bed), fluidized bed furnaces, cyclone furnaces, and kiln furnaces.

(Stoker furnace (fixed floor))
It is difficult to adjust the degree of combustion of the deinking floss, the combustibles are likely to be non-uniform, and the combustion of the deinking floss with a large amount of ash causes dust to fall due to the clearance between the grate. Since air is blown up and burned under the combustion material through the grate, calcium carbonate or the like becomes fly ash and is sent to the exhaust gas facility together with the exhaust gas, and the yield is likely to decrease.

(Fluidized bed furnace)
Since a particulate fluid medium such as silica sand is used as the fluid medium in the furnace, the silica sand is mixed into the regenerated particle aggregate, resulting in a decrease in quality. In addition, it is difficult to uniformly stir, and after mixing and burning the cinnabar in a fluidized bed, the cinnabar and the burned material are separated, and the cinnabar is returned to the combustion furnace and only the burned material is taken out. Since the same particle size occurs, it cannot be separated. Furthermore, since combustion is performed in a state of floating with dredged sand, it is difficult to adjust the degree of combustion, resulting in variations in quality. Combustion proceeds while a combustion product passes through a stalker (stepped shape) of a combustion furnace at a predetermined width, so that the ash is not sufficiently stirred and the combustion varies in the width direction. In addition, due to friction and collision with high-hardness silica sand, the combusted material is pulverized and discharged as fly ash, and the yield is reduced.

(Cyclone furnace)
Since it passes through the furnace in an instant, the fixed carbon in the combustion product is not sufficiently burned, leading to a decrease in the whiteness of the regenerated particle aggregate. In addition, fine particles are not separated by a cyclone and are sent to the exhaust gas treatment step together with the exhaust gas, resulting in a decrease in yield.

  From these facts, in the present invention, it is most preferable to use a kiln furnace as the combustion furnace. Further, as described above, it is preferable from the following point that the first combustion furnace is an internal heat kiln furnace and the second combustion furnace is an external heat kiln furnace.

  The external heat kiln furnace has a structure in which heating equipment is provided outside the kiln furnace, so the structure of the kiln furnace is relatively complicated, and a large amount of heat source is required to dry and burn the combustion products indirectly. It becomes. Therefore, when the external heat kiln furnace is used as the first combustion furnace in the primary combustion process of drying and burning the raw material having a high water content after dehydration, the drying / combustion efficiency is lowered, and the productivity is lowered. Temperature control becomes difficult and requires a large energy cost, which may reduce cost effectiveness.

  In addition, when the internal heat kiln furnace is used as the second combustion furnace, a large amount of diluted air is required to adjust the furnace temperature when the remaining carbon is burned. It is difficult to transfer heat uniformly into the internal heat kiln furnace. In addition, since it is difficult to suppress fluctuations in the furnace temperature, overburning and combustion unevenness of the combustion products are likely to occur. In addition, heavy fuel oil burner used for normal heating is contaminated with heavy fuel combustion residual carbon and sulfur oxides, resulting in decreased whiteness and variation at the product stage, making it difficult to equalize the quality of the resulting combustion product There is also a risk of becoming.

  For these reasons, in the present invention, it is optimal to use the first combustion furnace as the internal heat kiln furnace and the second combustion furnace as the external heat kiln furnace in the combustion process.

  Next, an example of a more preferable method for producing the regenerated particle aggregate used in the present invention will be described in more detail with reference to the drawings.

[Overview]
The production facility flow of the regenerated particle aggregate has a dehydration process, a drying process, a combustion process, and a pulverization process. Further, a deinking floss agglomeration process or granulation process, or a classification process between each process may be provided. Good.

  FIG. 1 is a schematic diagram illustrating a partial configuration example (an example of equipment including a drying process, a combustion process, and a combustion process) of a production facility flow of regenerated particle aggregates. This equipment is equipped with various sensors, and controls the state of combustibles, equipment, and processing speed.

  The deinking floss separated from the pulp fiber in the deinking process for producing waste paper pulp (not shown) is dehydrated by a known dehydration equipment (not shown) through various operations. The material after dehydration is desirably 40% by mass or more, preferably less than 90% by mass, more preferably 45 to 70% by mass, particularly preferably more than 50% by mass and 60% by mass or less.

  The material 10 after such dehydration is desirably pulverized to a particle size of 40 μm or less by a pulverizer (or pulverizer). The raw material 10 is cut from the storage tank 12 and charged by a charging machine 15 from one side of the first combustion furnace 14 which is an internal heat kiln furnace in which the main body is placed horizontally and rotates around the central axis. An exhaust gas chamber 16 is provided on one side of the first combustion furnace 14, and an exhaust chamber 18 is provided on the other side. The raw material 10 is passed through the discharge chamber 18, hot air is blown from the other side of the first combustion furnace 14, charged from the one side, and sequentially transferred to the other side as the first combustion furnace 14 rotates. Is dried and burned.

  Here, it is desirable that the hot air blown into the first combustion furnace 14 is prepared so that the oxygen concentration is 0.2 to 20%. The in-furnace temperature is preferably 300 ° C. or higher and lower than 500 ° C., preferably 400 ° C. or higher and lower than 500 ° C., particularly 400 to 450 ° C. Hot air is blown from a hot air generating furnace 20 provided with a burner 20A.

  From the exhaust gas chamber 16, exhaust gas subjected to drying and combustion is sent into the recombustion chamber 22. The fine powder of the combustion material contained in the exhaust gas is discharged from the lower part of the exhaust gas chamber 16 and reused. The exhaust gas is recombusted by the burner in the recombustion chamber 22, precooled by the precooler 24, passed through the heat exchanger 26, and discharged from the chimney 30 by the induction fan 28. Here, after raising the temperature of the outside air, the heat exchanger 26 is sent to the hot air generating furnace 20 and used for the hot air blown from the first combustion furnace 14 to recover the heat of the exhaust gas from the exhaust gas chamber 16. . The treatment of exhaust gas is effective for removing harmful substances contained in the exhaust gas.

  Combustion products that have undergone drying and combustion treatment in the first combustion furnace 14 are charged into a second combustion furnace 32 that is an external heat kiln furnace in which the main body is placed horizontally and rotates around the central axis. The particle size of the combusted material to be charged is preferably 40 μm or less. As a heat source in the second combustion furnace 32, it is preferable to adjust by electricity so that temperature control in the second combustion furnace 32 is easy and temperature control in the longitudinal direction is easy. Therefore, it is desirable that the externally heated second combustion furnace 32 is configured to again burn the combustion product obtained from the first combustion furnace 14 indirectly by an electric heater.

  In the second combustion furnace 32, the oxygen concentration is 5 to 20%, preferably 10 to 20%, particularly 10 to 15% by an air or oxygen supply mechanism (not shown) for adjusting the oxygen concentration. It is desirable to burn. The combustion temperature is 550 to 780 ° C, preferably 600 to 750 ° C. Further, the residence time in the second combustion furnace is preferably 60 minutes or longer, preferably 60 to 240 minutes, particularly 90 to 150 minutes, and 120 to 150 minutes for complete combustion of the remaining carbon. Is optimal.

  The regenerated particles that have been burned are cooled by a cooler 34, and then sorted by a particle size sorter 36 such as a vibration sieve, and the combustion is adjusted to a target particle size in a grinding process using a wet grinding machine or the like. The product is temporarily stored in the combustion product silo 38 and is sent to the application destination of the pigment.

  In addition, although the case where only the deinking floss was used as the raw material in the above-mentioned process was illustrated, the combustion product using the deinking floss as a main raw material and the raw material obtained by appropriately mixing other papermaking sludge such as papermaking sludge in the papermaking process It may be.

  As mentioned above, although the outline | summary of the manufacturing method of a regenerated particle aggregate was demonstrated, the detail, an application example, etc. are demonstrated below.

[material]
In the used paper pulp manufacturing process, in order to continuously produce used paper pulp of stable quality, used paper is selected and selected, and used paper of a certain quality is used. For this reason, the types, ratios, and amounts of inorganic substances brought into the waste paper pulp manufacturing process are basically constant. Moreover, even when plastics such as vinyl film, which cause fluctuations in unburned materials in the method for producing regenerated particle aggregates, are contained in the waste paper, these foreign matters lead to a deinking process for obtaining deinking floss. It can be removed in the previous stage. Accordingly, the deinking floss is a raw material for producing regenerated particles having extremely stable quality as compared with papermaking sludge generated in other processes such as a factory drainage process and a papermaking raw material preparation process.

  In the present specification, deinking floss refers to what is separated from pulp fibers in a deinking process for removing ink adhering to used paper in a used paper processing process for producing used paper pulp.

[Dehydration process]
For further dehydration of the deinking floss, known dehydration means can be appropriately used. In an example in the present embodiment, water is separated from the deinking floss by a screen, for example, and dehydrated. In the screen, the deinking floss dehydrated to 90 to 97% is preferably sent to, for example, a screw press and further dehydrated to a predetermined moisture content.

  When the moisture content of the raw material after dehydration exceeds 70%, the drying / combustion treatment temperature in the first combustion furnace is lowered, energy loss for heating is increased, and uneven combustion of the raw material is likely to occur. It becomes difficult to promote uniform combustion. Furthermore, the moisture in the exhaust gas discharged increases, and there is a risk that the recombustion treatment efficiency in dioxin countermeasures will be reduced and the load on the exhaust gas treatment equipment will be increased. Moreover, when the moisture content of the raw material after dehydration is as low as less than 40%, it causes excessive combustion of the deinking floss. By appropriately adjusting the moisture content of the raw material after dehydration, it is possible to contribute to the reduction of dehydration energy.

  As described above, if deinking of the deinking floss is performed in a multi-stage process and abrupt dewatering is avoided, the outflow of inorganic substances can be suppressed, and there is no fear that the flocs of the deinking floss become too hard. In the dehydration treatment, an auxiliary agent for improving the dehydration efficiency such as an aggregating agent for aggregating the deinking floss may be added, but it is preferable to use an aggregating agent that does not contain iron. When iron is contained, the whiteness of the regenerated particle aggregate may be reduced due to oxidation of iron.

  The deinking process of deinking floss is preferably adjacent to the regenerated particle aggregate manufacturing process from the viewpoint of production efficiency, but equipment is installed adjacent to the waste paper pulp manufacturing process in advance to transport the dehydrated product. It is also possible to transport to a fixed quantity feeder by means of conveyance such as a truck or belt conveyor, and to supply to the drying / combustion process from this constant quantity feeder.

  In the operation of supplying the raw material 10 after dehydration to the first combustion furnace 14, it is preferable that the average particle size is adjusted to a particle size of 40 mm or less by a pulverizer (or a pulverizer), more preferably the average particle size. It is desirable to adjust so that the diameter is 3 to 30 mm, more preferably the average particle diameter is in the range of 5 to 20 mm. Furthermore, it is more preferable to grind so that the ratio of the raw material 10 having a particle diameter of 50 mm or less is 70% by weight or more. In order to achieve a combustion treatment that does not cause a heat change of the calcium carbonate contained in the deinking floss, it is preferable that the particle diameter of the raw material is uniform, but if the average particle diameter is less than 3 mm, overcombustion tends to occur. On the other hand, when the average particle diameter exceeds 40 mm, it is difficult to achieve uniform combustion up to the raw material core.

  In the present specification, the average particle diameter and the ratio of the particle diameters are values measured using a sample solution sufficiently dispersed by a stirring type disperser, and the particle diameter in each combustion stroke is JIS Z 8801- 2 (2000) “Test sieve—Part 2: Metal plate sieve” means a value measured with a metal plate sieve as specified.

[First combustion process (drying / combustion process)]
The raw material 10 is cut out from the storage tank 12 and supplied to the first combustion furnace 14. The first combustion furnace 14 has an internal heat kiln furnace system in which a main body is placed horizontally and rotates around a central axis, and is charged by a charging machine 15 from one side of the first combustion furnace 14 (internal heat kiln furnace 14). The Hot air generated in the hot air generating furnace is sent from the discharge port side of the internal heat kiln furnace 14 so as to counter-current with the flow of the dehydrated product, and the internal heat kiln furnace 14 is heated. An exhaust gas chamber 16 is provided on one side of the internal heat kiln furnace 14, and an exhaust chamber 18 is provided on the other side. Hot air is blown from the other side of the internal heat kiln furnace 14 through the discharge chamber 18, charged from the one side, and sequentially transferred to the other side as the internal heat kiln furnace 14 rotates. Drying and burning takes place.

  That is, in this drying / combustion step, the dehydrated product is dried and burned gently from the supply port to the discharge port by drying and burning in an internal heat kiln furnace in which the main body is placed horizontally and rotates around the central axis. Combustion of organic content, suppression of pulverization of combustibles, stable control of the degree of combustion and particle size of dehydrated products with various properties such as formation of aggregates, hard and soft Can do. In addition, it is also possible to divide drying into another process and to put in a blow-up type dryer.

  Here, the hot air blown into the internal heat kiln furnace 14 is preferably adjusted so that the oxygen concentration is 0.05% or more, further 0.1% or more, and 20% or less. In particular, the oxygen concentration in the combustion process is preferably adjusted to 0.2 to 20%, more preferably 1 to 15%, and particularly preferably 5 to 12% at the upper end in the first combustion furnace. In the vicinity of the burner of the second combustion furnace, it is preferably adjusted to 5 to 20%, more preferably 10 to 20%, and particularly preferably 15 to 18%. In particular, if the oxygen concentration at the upper end of the first combustion furnace is less than 0.2%, not only uniform combustion does not proceed and uneven combustion proceeds, but also combustion requires enormous time and energy costs. There is a risk of becoming.

  Since oxygen is consumed by the combustion (oxidation) of the raw material, the oxygen concentration varies depending on the state of combustion. When the oxygen concentration is excessively low, it is difficult to achieve sufficient combustion. The oxygen concentration in the combustion furnace decreases as oxygen is consumed due to the combustion of the raw material, etc., but the oxygen concentration is increased by blowing or exhausting oxygen-containing gas such as air by a hot air generator for combustion. It is also possible to finely adjust the temperature in the combustion furnace by blowing or exhausting oxygen-containing gas, and the raw material can be uniformly burned without unevenness. it can.

  The furnace temperature (combustion temperature) of the first combustion furnace is preferably 300 ° C. or higher and lower than 500 ° C., more preferably 400 ° C. or higher and lower than 500 ° C., and particularly preferably 400 to 450 ° C. In the first combustion furnace, it is preferable to combust in a temperature range of 300 ° C. or more and less than 500 ° C. for the purpose of slowly burning organic substances that can be easily combusted and suppressing the generation of residual carbon that is difficult to combust. If the combustion temperature is excessively low, the organic matter may be insufficiently combusted. If the combustion temperature is excessively high, overcombustion occurs, and calcium oxide is easily generated due to decomposition of calcium carbonate. Furthermore, when the temperature of the hot air is 500 ° C. or higher, drying / combustion proceeds locally faster than the particle alignment of the burned material having various properties such as hard and soft, so that the unburned surface of the particles It becomes difficult to make the difference between the rate and the internal unburned rate small and uniform.

  In addition, a hot air is blown in from the hot air generation furnace 20 provided with 20 A of burners.

  From the exhaust gas chamber 16, exhaust gas subjected to drying and combustion is sent into the recombustion chamber 22. The fine powder is discharged from the lower part of the exhaust gas chamber 16, and is mixed again with the raw material and reused.

  The exhaust gas is recombusted by the burner in the recombustion chamber 22, precooled by the precooler 24, passed through the heat exchanger 26, and discharged from the chimney 30 by the induction fan 28. Here, after raising the temperature of the outside air, the heat exchanger 26 is sent to the hot air generating furnace 20 and is used for hot air blown from the internal heat kiln furnace 14 to recover the heat of the exhaust gas from the exhaust gas chamber 16. .

  The first combustion furnace preferably burns with a residence time of 30 to 90 minutes under the above conditions in order to slowly burn the easily combustible organic substances contained in the deinking floss and suppress the formation of residual carbon. Is preferred. A residence time (burning time) of 40 to 80 minutes is more preferable in terms of organic combustion and production efficiency, and a residence time (burning time) of 50 to 70 minutes ensures constant quality. Is particularly preferable. If the combustion time is less than 30 minutes, sufficient combustion may not be performed and the proportion of residual carbon may increase. On the other hand, when the combustion time exceeds 90 minutes, thermal decomposition of calcium carbonate occurs due to overcombustion of the raw material, and the resulting regenerated particle aggregate may be extremely hard.

  In particular, it is preferable to dry and burn so that the unburned rate of the combustion product supplied in the second combustion step of the next step is 2 to 20% by mass, and the unburned rate is more preferably 5 to 17% by mass %, Particularly preferably 7 to 12% by mass.

  As described above, by setting the unburned rate of the combustion product supplied in the second combustion step to 2 to 20% by mass, combustion in the second combustion step can be efficiently performed in a short time, By the stable heating in the external heating furnace, it is possible to obtain a combustion product having a low hardness and a whiteness of 80% or more, and further a high whiteness of 70% or more. In particular, if the unburned rate of the combustion material supplied in the second combustion process is less than 2% by mass, the energy cost in the primary combustion furnace may be high and the hardness of the combustion material may be relatively high. In some cases, the quality of the combustion product may be reduced, such as a decrease in the whiteness of the combustion product at the outlet of the second combustion furnace.

[Second combustion process]
Combustion products that have undergone drying and combustion treatment in the internal heat kiln furnace 14 are loaded into an external heat kiln furnace corresponding to a second combustion furnace 32 having an external heat jacket 31 that rotates horizontally around the central axis through a transfer channel. Entered. In the second combustion furnace 32 (external heat kiln furnace 32), while the combustion product is heated with external heat, the transfer of the raw material in the combustion furnace is controlled by a lifter provided on the inner wall of the kiln furnace, and the combustion is performed slowly. As a result, the unburned portion is burned more uniformly.

  In the combustion in the second combustion furnace, the residual organic matter that could not be combusted in the first combustion furnace, for example, residual carbon, was burned, so that the particle diameter was adjusted to be smaller than the particle diameter of the raw material supplied in the first combustion furnace. It is preferable to use a combustion product. The combustion product after the drying / combustion step (combustion product at the second combustion furnace inlet) is preferably adjusted so that the average particle size is 10 μm or less, further 1 to 8 μm, and particularly 1 to 5 μm.

  If the average particle size of the combustion product at the inlet of the second combustion furnace is less than 1 μm, there is a risk of overcombustion. Conversely, if the average particle size exceeds 10 μm, the remaining carbon is difficult to burn and combustion does not proceed to the core. The whiteness of the resulting regenerated particle aggregate may be lowered. In order to ensure stable production in the second combustion furnace, it is preferable to adjust the particle size so that the combustion product having an average particle size of 1 to 8 μm is 70% by mass or more. Therefore, it is beneficial to the possibility of practical use in terms of making the quality of the regenerated particle aggregate obtained uniform. Furthermore, when classification is performed after drying, there is an advantage that combustion products of small-diameter particles can be surely removed and the processing efficiency is improved.

  As an external heat source in the external heat kiln furnace 32, an electric heating type electric furnace in which temperature control in the external heat kiln furnace 32 is easy and temperature control in the longitudinal direction is easy is suitable. Therefore, it is desirable that the external heat kiln furnace 32 is an electric heater.

  By using electricity for external heat, it becomes possible to finely adjust the temperature and control the internal temperature uniformly, and the degree of combustion of dehydrated products with various properties such as formation of aggregates, hard and soft Can be stably controlled.

  Furthermore, the electric furnace can be provided with a temperature gradient arbitrarily by providing a plurality of electric heaters in the flow direction of the furnace, and can maintain the temperature of the combustion product for a certain period of time. Residual organic content in the combusted material after passing through 1 combustion furnace, especially residual carbon, can be brought close to zero without causing decomposition of calcium carbonate in the 2nd combustion furnace. Compared with the heavy calcium carbonate currently used, the regenerated particle aggregate of high whiteness can be obtained with a comparatively low wire abrasion degree.

  In the external heat kiln furnace 32, it is desirable to adjust the oxygen concentration to be 5 to 20%, more preferably 10 to 20%, and most preferably 10 to 15%. The oxygen concentration can be controlled by controlling the amount of oxygen or air input to the second combustion furnace by an appropriate means. However, in FIG. 1, illustration of specific forms is omitted. In particular, if the oxygen concentration in the external heat kiln furnace is less than 5%, there is a possibility that the combustion of residual carbon that is difficult to burn does not proceed.

  The combustion temperature in the second combustion furnace is preferably 550 to 780 ° C, more preferably 600 to 750 ° C. In the second combustion furnace, as described above, since it is necessary to burn the residual organic matter that has not been burned in the first combustion furnace, particularly the residual carbon, it is preferable to burn at a higher temperature than the first combustion furnace. If the combustion temperature in the second combustion furnace is less than 550 ° C., it is difficult to sufficiently burn the residual organic matter. Conversely, if the combustion temperature exceeds 750 ° C., the oxidation of calcium carbonate in the combustion product proceeds. The particles may become hard.

  In this specification, the combustion temperature (primary combustion temperature) in the first combustion furnace is the outlet temperature of the first combustion furnace, and the combustion temperature (secondary combustion temperature) in the second combustion furnace is a radiation thermometer. Based on the inner wall surface temperature of the second combustion furnace.

  The residence time in the second combustion furnace is preferably 60 minutes or longer, more preferably 60 to 240 minutes, particularly preferably 90 to 150 minutes, and most preferably 120 to 150 minutes. In particular, the remaining carbon must be burned slowly at a high temperature that does not cause decomposition of calcium carbonate as much as possible. If the residence time in the second combustion furnace is less than 60 minutes, the burning of the remaining carbon is not possible in a short time. On the contrary, if it exceeds 240 minutes, calcium carbonate may be decomposed. In order to perform stable production of the combustion products, it is preferable that the residence time is 60 minutes or longer, and in order to prevent overcombustion and ensure productivity, it is preferable to burn the residence time in 240 minutes or less.

  It is suitable to adjust the average particle size of the combustion product discharged from the external heat kiln furnace 32 to 10 μm or less, more preferably 1 to 8 μm, and most preferably 1 to 5 μm.

  The combusted product after the combustion is an aggregate of regenerated particles, and after being cooled by the cooler 34, a product having a target particle size is temporarily stored in the combustion product silo 38 by a particle size sorter 36 such as a vibration sieve. To be used for pigments.

[Crushing process]
The combusted product (regenerated particle aggregate) that has undergone the second combustion step is further finely granulated to a necessary particle size in a known dispersion / pulverization step and used as a pigment for a coating agent.

  For example, after combustion in the second combustion step, the obtained particles are pulverized using a dry pulverizer such as a jet mill or a high-speed rotary mill, or a wet pulverizer such as an attritor, a sand grinder, or a ball mill. In addition, as for the particle diameter of the regenerated particle aggregate used as a pigment in the present invention, the volume average particle diameter is preferably 1.0 to 5.0 μm as described later.

[Attached process]
For example, in the production facility for the regenerated particle aggregate shown in FIG. 1, in order to obtain more stable quality, it is preferable to classify the particle diameter of the regenerated particle aggregate uniformly in each step. By feeding back coarse particles and fine particles to the previous process, quality can be further stabilized.

  In addition, it is preferable to granulate the deinked floss that has been subjected to dehydration in the previous stage of the drying process, and it is more preferable to classify the granulated product so as to have a uniform particle diameter. Again, the quality can be further stabilized by feeding back coarse granulated particles and fine granulated particles to the previous process. Known granulation equipment can be used for granulation, and equipment of a rotary type, a stirring type, an extrusion type, etc. are suitable.

  Further, it is preferable to remove in advance other than the raw material of the regenerated particle agglomerate, for example, sand, plastic foreign matter, metal, etc. with a pulper, screen, cleaner etc. in the previous stage leading to the deinking process of the used paper pulp manufacturing process It is preferable from the viewpoint of removal efficiency to remove. In particular, iron oxide is a causative substance for reducing the whiteness of the fine particles. Therefore, it is recommended to avoid the iron content and selectively remove it. Each process is designed or lined with materials other than iron to prevent iron from being mixed into the system due to wear, etc., and a high magnetic material such as a magnet is installed in the drying / classifying equipment, etc. It is preferable to remove iron.

  An internal heat kiln furnace or an external heat kiln furnace used as a suitable combustion furnace can lift and agitate the combusted material without slipping by making the internal refractory into a hexagonal or octagonal shape instead of a circumferential shape. However, in reality, the kiln furnace has a cylindrical shape, and it is optimal to provide a lifter for stirring the combusted material in terms of uniform combustion of the raw materials and uniform quality. This is also considered to be related to intentionally burning the entire raw material slowly at a low temperature in the first combustion furnace.

[About the lifter of the second combustion furnace]
By arranging a helical lifter and / or a parallel lifter parallel to the axial center from the one end side to the other end side on the inner wall in the second combustion furnace, uniform combustion of the raw material and uniform quality Can be achieved. In particular, it is desirable to dispose the spiral lifter and the parallel lifter parallel to the axial center from the charging side to the discharge side of the combusted material.

  According to the structure of the lifter, the contents introduced from the charging side are first lifted while being fed by an appropriate amount toward the other end side by the spiral lifter, and dropped, and the organic components resulting from the raw material Gasifies and efficiently contacts with the generated combustion gas (combustible gas), and further contacts the combustion gas (combustible gas) efficiently by repeating the operation of being lifted and dropped by a parallel lifter. Therefore, the contents can be combusted efficiently with heat exchange. In particular, the amount of content fed into the parallel lifter is controlled by the spiral lifter, so that the content is properly lifted and dropped at the parallel lifter portion, and the content is burned uniformly and efficiently. be able to. Further, since there is no fear of damage to the refractory, there is no decrease in the purity of the combustion product, and its production capacity is improved.

  In addition, when the spiral lifter and the parallel lifter are made of metal such as a stainless steel plate having heat resistance, for example, since the temperature is relatively low, sufficient durability and strength can be secured without using expensive heat-resistant materials. In addition, since the heat transfer efficiency is higher than that of a refractory lifter or the like, the heat efficiency is further improved.

  The lifter of the second combustion furnace will be described with reference to the drawings. FIG. 2 is a partial schematic view of the second combustion furnace, (a) is a partially broken schematic cross-sectional view of the second combustion furnace, and (b) is a schematic plan view of an internal development of the second combustion furnace. In FIG. 2, the combusted material is charged from the left side of the second combustion furnace 32 (shown as “charging” in FIG. 2A), and is configured to be rotationally driven by a rotational driving means (not shown). And discharged from the other end.

  The second combustion furnace 32 is configured by lining a fireproof wall 32B made of fireproof castable or fireproof brick on the inner surface of a cylindrical outer casing 32A. On the inner surface of the refractory wall 32B of the second combustion furnace 32, a plurality of spirals (eight in FIG. 2) are inclined at an inclination angle of 45 to 70 ° with respect to the axis of the second combustion furnace 32 on the input side. The lifters 4 are projected at equal intervals. Further, a plurality of parallel lifters 5A having appropriate lengths parallel to the axis of the second combustion furnace 32 are provided at equal intervals in the circumferential direction on the other end side of the region where the spiral lifters 4 are disposed (eight in FIG. 2). ) And a plurality of rows (eight rows in FIG. 2) arranged in a staggered manner in the axial direction.

  Further, the parallel lifter 5A is continuously formed on the right side of FIG. 2 toward the discharge portion (not shown). In this case, since the temperature is low on the charging side, the parallel lifter 5A on the charging side is preferably formed of a metal plate having heat resistance and corrosion resistance, such as a stainless steel plate, and becomes high on the discharge side. Therefore, it is desirable that the parallel lifter 5A on the discharge part side has refractory properties.

  In FIG. 2, the spiral lifter 4 is fixedly disposed on mounting brackets 6 disposed at appropriate intervals in the longitudinal direction. Further, each parallel lifter 5A is fixedly disposed on each mounting bracket 5B.

  Furthermore, it is possible to provide only one of a spiral lifter or a parallel lifter as required.

  For example, in the method for producing regenerated particle aggregates based on the production equipment flow shown in FIG. 1, the weight loss in decomposition (change to calcium oxide) of calcium carbonate that occurs in the vicinity of 700 ° C. in differential thermal analysis using a differential thermothermal gravimetric simultaneous measurement device. By controlling combustion of the deinking floss so that the (rate) is 50% or more, the progress of oxidation of the calcium component can be suppressed more accurately, and the resulting regenerated particle aggregate can be prevented from becoming hard. There is an advantage.

  As mentioned above, although an example of the suitable manufacturing method of the regenerated particle aggregate which is a pigment was demonstrated in detail, in this invention, as this regenerated particle aggregate, the regenerated particle aggregate obtained through the above processes is used. A silica-coated regenerated particle aggregate whose surface is coated with silica can also be suitably used.

  The silica-coated regenerated particle aggregate whose surface is coated with silica has high porosity on its surface and has a significantly increased specific surface area. Therefore, as described later, it is bonded to silanol PVA as an adhesive. The power is further improved, and for example, the absorption drying property of newspaper offset ink can be further improved, the printing density can be further improved, and the printing opacity can be further improved. A typical example of the silanol PVA is R polymer (trade name, manufactured by Kuraray Co., Ltd.).

  The deinking floss used in the deinking process of the used paper processing process used in the present invention has a tendency to increase the content of calcium carbonate in accordance with the recent neutral papermaking, and in the resulting regenerated particle aggregate The proportion of calcium tends to be high. When the regenerated particle aggregate having a high proportion of calcium is used as a pigment in this manner, the blank paper opacity of the resulting newspaper may be slightly reduced, but the silica-coated regenerated particle aggregate in which silica is precipitated on the surface, The function as inorganic particles for papermaking is extremely high, and newsprint paper using the silica-coated regenerated particle aggregate as a pigment has sufficiently improved white paper opacity and oil absorption.

  The silica covering the surface of the regenerated particle aggregate can be used without particular limitation as long as it is not naturally produced silica but synthetic silica by some chemical reaction. Specific examples include colloidal silica, silica gel, and anhydrous silica. These synthetic silicas make use of excellent properties such as high specific surface area, high gas adsorbing capacity, fineness, permeability to pores and large adsorbing power, high adhesion, and high oil absorption. It is used in a wide range of fields. Among these, colloidal silica is an amorphous silicic acid sol obtained by removing impurities from a silicic acid compound, and stabilizing the sol by adjusting pH and concentration, and has an amorphous shape such as a spherical shape, a chain shape, and an amorphous shape. Silica. Silica gel is hydrous silicic acid obtained by decomposing sodium silicate with an inorganic acid. Anhydrous silica is obtained by hydrolysis of silicon tetrachloride.

  The silica-coated regenerated particle aggregate is prepared by suspending the regenerated particle aggregate formed in the combustion step in an alkali silicate solution and adding a mineral acid, and coating the regenerated particle aggregate with silica. For example, the following method can be suitably employed.

  First, regenerated particle aggregates are added to and dispersed in an alkali silicate solution, and after preparing a slurry, the temperature of the liquid is kept at about 60 to 100 ° C., more preferably at a predetermined pressure in a sealed container, while the mixture is heated and stirred. An acid is added to form a silica sol. Subsequently, silica can be deposited on the surface of the regenerated particle aggregate by adjusting the pH of the final reaction solution to a neutral to weak alkaline range. Silica deposited on the surface of the regenerated particle aggregate in this way reacts at a high temperature with a dilute solution of mineral acid such as sulfuric acid, hydrochloric acid, nitric acid, etc., using alkali silicate (for example, sodium silicate: water glass) as a raw material. Silica sol particles having a particle size of about 10 to 20 nm, obtained by hydrolysis reaction and polymerization of silicic acid.

  In addition, silica sol fine particles with a particle size of several nanometers, which are produced by adding mineral acid such as dilute sulfuric acid to an alkali silicate solution such as sodium silicate solution, cover the entire porous surface of the regenerated particle aggregate. As a result of the crystal growth of the silica sol fine particles, the silica sol fine particles on the surface of the inorganic fine particles are bonded to the surface of the inorganic particles by the bond formed between the silica sol fine particles on the surface of the inorganic fine particles and the silicon, calcium, or aluminum included in the regenerated particle aggregate. It can also be deposited. In this case, the pH when adding the acid to the alkali silicate solution is also in a neutral to weak alkaline range, and the pH is preferably adjusted in the range of 8 to 11. This is because if the acid is added until the pH reaches an acidic condition of less than 7, white carbon may be generated instead of silica sol particles.

The type of the alkali silicate solution is not particularly limited, but a sodium silicate solution (No. 3 water glass) is particularly desirable from the viewpoint of easy availability. As the concentration of the alkali silicate solution, in order to prevent the silica component in the regenerated particle aggregate from being reduced and the silica from becoming difficult to precipitate on the surface of the regenerated particle aggregate, the silicic acid content in the solution (in terms of SiO ₂ ) Is preferably 3% by mass or more, and the silica deposited on the surface of the regenerated particle aggregate becomes white carbon from the form of the silica sol, and the porosity of the regenerated particle aggregate is obstructed, resulting in opacity and printability. In order to eliminate the possibility of the improvement effect being insufficient, the silicic acid content is preferably 10% by mass or less.

  Thus, the regenerated particle aggregate suitably used in the present invention preferably contains three components of calcium, silicon and aluminum in its particle constituent components. In the elemental analysis using an X-ray microanalyzer (model number: E-MAX S-2150, manufactured by Hitachi, Ltd./Horiba, Ltd.), the particle constituents of the regenerated particle aggregate are converted to oxides, Calcium, silicon and aluminum are in a mass ratio of 30 to 82: 9 to 35: 8 to 35, more preferably 40 to 82: 9 to 30: 9 to 30, especially 60 to 82: 9 to 20: 9 to 20 It is preferably contained.

  In particular, when the regenerated particle aggregate is a silica-coated regenerated particle aggregate, in the elemental analysis by the X-ray microanalyzer, the particle component of the silica-coated regenerated particle aggregate includes calcium in terms of oxide. It is preferable that silicon, and aluminum and aluminum are contained in a mass ratio of 10 to 80:10 to 80: 5 to 29, more preferably 15 to 80:15 to 80: 5 to 25.

Further, in the silica-coated regenerated particle aggregate that can be suitably used in the present invention, the furnace temperature (combustion temperature) of the first combustion furnace is preferably 300 ° C. or higher, less than 500 ° C., more preferably 400 ° C. or higher. The silica-coated regenerated particle aggregate obtained under the conditions of less than 500 ° C., particularly preferably 400 to 450 ° C., is obtained by gently burning combustible organic substances, so that the product has uneven color. L ^* = 75.0 to 80.0, a which is the same as newsprint paper having no coating layer due to a synergistic effect with the dye imparted in the formation of the coating layer. ^* = -3.50～0.50, it is easy to obtain a newsprint is b ^* = 3.50 to 7.50.

  In the regenerated particle aggregate (hereinafter described as a concept including a silica-coated regenerated particle aggregate), the total content ratio of calcium, silicon, and aluminum in terms of oxide is in the particle constituents of the regenerated particle aggregate. It is preferably 85% by mass or more, more preferably 90% by mass or more.

  The regenerated particle aggregate used in the present invention contains silicon, and the silica particles made of silicon are fine, so the optical refractive index is high. Therefore, for example, newsprint paper in which a regenerated particle aggregate containing silicon in an oxide equivalent or more in the above mass ratio is coated on the surface as a pigment has particularly high blank paper opacity.

  In addition, for example, when a regenerated particle aggregate containing calcium in an amount of the above-mentioned mass ratio in terms of oxide is coated on the surface as a pigment, it is possible to improve the whiteness of newspaper paper obtained in particular.

  In order to adjust the mass ratio of calcium, silicon and aluminum in the particle constituents of the regenerated particle aggregate within the above range in terms of oxides, it is preferable to originally adjust the raw material composition in the deinking floss, In the drying process, combustion process, and if necessary, in the classification process, it is also possible to adopt a method that includes a coating floss with a clear origin or a preparation process floss by spraying, or a method that includes incinerator scrubber lime. It is.

  For example, neutral paper-making wastewater sludge for the adjustment of calcium in recycled particle aggregates and wastewater sludge from the coated paper manufacturing process, and coated paper that is added in large quantities as an opacity improver for the adjustment of silicon. For the production of wastewater sludge, for the adjustment of aluminum, papermaking wastewater sludge using an acid papermaking system or other sulfuric acid band, or wastewater sludge from the high quality papermaking process in which a large amount of clay is used can be used.

  Further, in the regenerated particle aggregate, in order to adjust the total content ratio of calcium, silicon, and aluminum to 85% by mass or more in terms of oxides, for example, a means of using a flocculant that does not contain iron in the flocculation treatment of drainage sludge, Designing or lining the manufacturing equipment process with materials other than iron to prevent iron from entering the system due to wear, etc.Furthermore, high magnetic materials such as magnets are installed in the drying / classifying equipment to reduce the iron content. It is possible to adopt a means for removing. In particular, iron is preferably a causative substance that lowers the whiteness by oxidation, and thus is preferably removed selectively.

  Further, the regenerated particle aggregate contains silicon, but since the primary particles of silica made of silicon are fine, the optical refractive index is high. Therefore, for example, when a regenerated particle aggregate containing silicon in an oxide equivalent or more in the above-mentioned mass ratio is coated on the surface as a pigment, it is possible to improve the blank opacity of newspaper paper obtained in particular.

  The particle diameter of the regenerated particle aggregate used in the present invention is, for example, sufficient to prevent the occurrence of paper dust in printing such as high-speed offset printing, and from the viewpoint of easily imparting an appropriate sliding property. Is preferably 1.0 μm or more, more preferably 1.2 μm or more, and the volume average particle diameter is obtained from the viewpoint of obtaining a fine printed surface, more rapid ink absorption drying property and ink fixing property on the paper surface. Is preferably 5.0 μm or less, more preferably 4.8 μm or less.

  In the regenerated particle aggregate used in the present invention, the ratio of aggregates having a particle size volume distribution of 20 μm or less is 70% by mass or more, and the ratio of aggregates having a particle size volume distribution exceeding 18 μm is 0. More preferably, it is adjusted to 5% by mass or less.

  In this specification, the volume average particle size and volume distribution of the regenerated particle aggregate are measured with a laser particle size distribution measuring device (laser diffraction type particle size distribution measuring device SALD-2200, standard refractive index (1), This is a value (value based on laser analysis) measured by Shimadzu Corporation.

  Furthermore, in the present invention, white paper unevenness on the surface of newsprint paper can be eliminated, and newsprint paper with water resistance, suppression of paper wetting and stretching with fountain solution, surface strength, suppression of misregistration, ink absorption, etc. In view of further improving the characteristics, in the elemental analysis with an X-ray microanalyzer on the surface of the coating layer, the area where the regenerated particle aggregates are present is preferably 30% or more, more preferably 32% or more. In addition, considering that the regenerated particle aggregate is a flexible secondary aggregate and excessive blending causes generation of paper dust and reduction in paper quality in high-speed rotary printing, the area where the regenerated particle aggregate exists is an area. The ratio is preferably about 90% or less.

  Conventional pigments for coating generally have a whiteness of 85% or more in a powder whiteness meter (manufactured by Kett Scientific Laboratory, type C-100), and are intended for the present invention. When used for newsprint with whiteness of 52 to 60%, there is a problem that white unevenness occurs on the paper surface due to the difference in whiteness. On the other hand, the regenerated particle agglomerates that can be suitably used in the present invention are originally produced from gray deinked floss as a raw material, and originally produced regenerated particle agglomerates with a high whiteness are provided in the present invention. Therefore, a regenerated particle aggregate having a desired whiteness can be produced. Therefore, in the present invention using the regenerated particle aggregate, the problem of white unevenness should be considered in the past while retroactively improving the opacity as a problem. The above-mentioned problem does not occur even if the existing area is 30% or more, further 32% or more in the area ratio, there is little white unevenness even though it has a coating layer, high opacity, blanket dirt due to paper dust, clogging of the sword tip In addition, newsprint with no misregistration and excellent printability can be provided.

Furthermore, in the regenerated particle aggregate that can be suitably used in the present invention, the furnace temperature (combustion temperature) of the first combustion furnace is preferably 300 ° C. or higher and lower than 500 ° C., more preferably 400 ° C. or higher and 500 ° C. Since the regenerated particle aggregate obtained under conditions of less than ℃, particularly preferably 400 to 450 ℃, is obtained by gently burning combustible organic matter, the product has little color unevenness and is uniform L ^* = 75.0-80.0, a ^* = − 3, which is equivalent to newsprint without a coating layer due to a synergistic effect with the dye applied in forming the coating layer. It becomes easy to obtain newsprint with .50 to 0.50 and b ^* = 3.50 to 7.50.

  In this specification, the regenerative particle agglomerate existing area is an area of 12,000 times the area of a certain area, 10 different parts of the sample are photographed, and elemental analysis in each area is performed with an X-ray microanalyzer, and image analysis is performed. The part detected by overlapping calcium, silicon and aluminum with the apparatus was selected as the regenerated particle aggregate, and the area ratio of the part detected by overlapping calcium, silicon and aluminum was calculated with the image analyzer. Is.

  Further, the regenerated particle aggregate has an oil absorption amount of 80 ml / 100 g in accordance with “Pigment test method—Part 13: Oil absorption amount—Section 1: Refined oil oil method” described in JIS K 5101-13-1. As described above, it is preferably 90 ml / 100 g or more, 200 ml / 100 g or less, more preferably 145 ml / 100 g or less. When the oil absorption amount of the regenerated particle aggregate is less than 80 ml / 100 g, there is little difference between the blank paper opacity and the printing opacity, and there is a possibility that print back-through occurs or neppari occurs. There is a tendency that the pH of the paper surface tends to be high, and the ink density may be lowered.

The printing opacity referred to in the present invention is an offset rotary printing machine (model number: RI-2 type, manufactured by Ishikawajima Industrial Machinery Co., Ltd.), an offset rotary printing ink (trade name: News Zet Naturalis (black), large The ratio of the back-surface reflectance after printing to the back-surface reflectance before printing when the ink amount of Nippon Ink Chemical Co., Ltd.) was changed and the printing surface reflectance was 9%:
(Back side reflectance after printing / Back side reflectance before printing) × 100 (%)
Is what we asked for. A spectral whiteness colorimeter (manufactured by Suga Test Instruments Co., Ltd.) is used for measuring the reflectance.

In newsprint paper, the opacity of appearance is regarded as important, so it is preferable to determine the printing opacity from the ratio of the back surface reflectance after printing to the back surface reflectance before printing at a constant printing surface reflectance. is there. L ^* , a ^* , b ^{* of} the paper surface calculated by the CIELab color space defined in JIS P 8150 is L ^* = 75.0-80. Newspaper with little white unevenness while having a coating layer by providing a coating layer such that 0, a ^* = − 3.50 to 0.50, b ^* = 3.50 to 7.50 Can be obtained.

  In the present invention, in order to ensure appropriate smoothness by the newspaper, and to ensure high opacity and ink absorption drying property, the amount of regenerated particle aggregate is 30% by mass or more of the total amount of pigment, Is preferably adjusted to 35% by mass or more.

  The regenerated particle aggregate is composed of calcium, silicon, and aluminum as constituent components, preferably 30 to 82: 9 to 35: 8 to 35, more preferably 40 to 82: 9 to 30: 9. -30, particularly preferably 60-82: 9-20: 9-20, in the case of silica-coated regenerated particle aggregates, preferably 10-80: 10-80: 5-29, more preferably 15 It is contained in a mass ratio of ˜80: 15 to 80: 5 to 25, and unlike various fine particles used conventionally such as calcium carbonate and white carbon, it does not exhibit only the effects unique to the fine particles. Since it has a leveled property, it can be adjusted to be 30% by mass or more, and further 35% by mass or more of the total amount of the pigment, compared with other combinable pigments. Without being biased such positive, it can exhibit the formation and opacity of uniform coating layer.

  As the pigment that is the main component of the coating agent, it is sufficient that at least the specific regenerated particle aggregate is blended, for example, from the point that the characteristics of newsprint at the time of printing such as offset color printing is further improved, It is preferable that a high aspect pigment having an aspect ratio of 20 or more is blended together with the regenerated particle aggregate.

  Examples of the high aspect pigment include high aspect clays such as kaolin clay and delaminated clay, and other examples include clays having an aspect ratio of about 50, and an aspect ratio of up to 100 at the laboratory level. Calcium carbonate has been developed. Such a pigment having an aspect ratio close to 100 has a problem that a pigment having a large particle diameter cannot be produced and is expensive, so that a pigment having an aspect ratio of about 50 may be exemplified. it can.

  The aspect ratio of the high aspect pigment is not only able to obtain a high-definition printing surface by improving the flatness of the newspaper surface during printing such as offset color printing, but also in parallel to the printing surface. It is preferably 20 or more, more preferably 21 or more from the viewpoint that the opacity is further improved due to the orientation. In consideration of the price and the quality obtained, the aspect ratio of the high aspect pigment is preferably 30 or less.

  The particle diameter of the high aspect pigment used in the present invention is, for example, a volume average particle diameter of 2.0 μm or more, and further 2.2 μm from the viewpoint of more sufficiently preventing the occurrence of paper dust in printing such as high-speed offset printing. The volume average particle size is preferably 15.0 μm or less, more preferably 13.0 μm from the viewpoint of obtaining a fine print surface, more rapid ink absorption drying property and ink fixing property on the paper surface. The following is preferable.

  When a high aspect pigment is used in combination with the regenerated particle aggregate, white unevenness on the newspaper surface can be eliminated, and further, water resistance, suppression of wetting and stretching of the paper against dampening water, surface strength, and misregistration can be achieved. In the elemental analysis by X-ray microanalyzer on the surface of the coating layer, the total existence area of the regenerated particle aggregate and the high aspect pigment is expressed as an area ratio because the characteristics of newsprint such as suppression and ink absorption are further improved. It is preferably 45% or more, more preferably 48% or more. Although it is possible to make the total area of the regenerated particle aggregate and the high aspect pigment 100% in area ratio, for example, the surface strength of the paper surface in printing such as high-speed offset printing, and the suppression of paper dust generation In consideration, when an inexpensive pigment such as talc is used, the total existence region of the regenerated particle aggregate and the high aspect pigment is preferably about 100% or less in area ratio.

  In this specification, the total existence area of the regenerated particle aggregate and the high aspect pigment is the same as the existence area of the regenerated particle aggregate. Then, the elemental analysis in each region was performed with an X-ray microanalyzer, the area (A) where calcium, silicon, and aluminum were detected by being overlapped was measured with an image analyzer, and the height visually confirmed with the X-ray microanalyzer The area (B) calculated by multiplying the number of aspect pigments by the average area of 10 high aspect pigments was measured, and the total area ratio was calculated from the area (A) and area (B). It is.

  Further, as the pigment, in addition to the regenerated particle aggregate and the high aspect pigment, for example, light calcium carbonate, heavy calcium carbonate, talc, clay, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, Satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica (white carbon), colloidal silica, colloidal alumina, pseudoboehmite, aluminum hydroxide, alumina, lithopone, zeolite, hydrous halloysite, Inorganic pigments such as magnesium carbonate, magnesium hydroxide, porous synthetic amorphous silica, porous magnesium carbonate, porous alumina; styrene plastic pigment, acrylic plastic pigment, polyethylene, microcapsule, urea Fat, such as organic pigments, such as melamine resins, among pigments which are commonly incorporated into coating agents can be selected and used one or more suitably.

  In addition, when using pigments other than the said reproduction | regeneration particle | grain aggregate, it is preferable that the average particle diameters measured with the laser method are about 2-15 micrometers, for example. Moreover, as the whole pigment mix | blended with a coating agent, it is preferable that the average particle diameter measured by the laser method is about 0.1-10 micrometers, for example, and the particle size distribution (volume basis) of 15 micrometers or less is 55-55. It is preferably about 70%.

  There are no particular limitations on the type of adhesive that is blended in the coating agent together with the pigment. For example, starches such as oxidized starch, modified starch, esterified starch, and dextrin; synthetic resins such as polyvinyl alcohol (hereinafter referred to as PVA) Adhesives: Water-soluble adhesives such as casein, soy protein, and synthetic proteins, and conjugated diene copolymer latex such as styrene-butadiene copolymer; polymers or copolymers of acrylate esters, etc. Acrylic copolymer latex; vinyl polymer latex such as ethylene-vinyl acetate polymer; alkali-soluble, alkali-swellable or non-alkaline modified with various polymer latex modified with functional group-containing monomer such as carboxyl group Examples include latexes such as soluble polymer latex, and one or more of these are selected appropriately. It can be used. Among these, a newspaper paper that exhibits moderate ink absorption ability due to the binding with the regenerated particle aggregate, has high water resistance, and is further suppressed from being wet and stretched even with frequent fountain solution. From the viewpoint that it can be used, it is particularly preferable to use starch such as oxidized starch or PVA.

  As the PVA, for example, those having an average degree of polymerization of about 50 to 2400 and a saponification degree of about 98.0 to 99.0 mol% can be suitably used.

  The blending ratio of the pigment and the adhesive in the coating agent is such that, for example, the effect of improving the characteristics of the newsprint at the time of printing such as offset color printing can be expressed sufficiently with respect to 100 parts by mass of the pigment. It is preferable to adjust so that an agent may be 15 mass parts or less, Furthermore, 10 mass parts or less. Further, in order to prevent the amount of the adhesive from being too small and the adhesion of the coating agent to the base paper from becoming insufficient, the adhesive is 5 parts by mass or more, further 8 parts by mass or more with respect to 100 parts by mass of the pigment. It is preferable to adjust so that.

  The coating agent is mainly composed of a pigment and an adhesive, and the total amount of these pigment and adhesive in the coating agent is usually preferably about 90% by mass or more.

  As described above, the newsprint of the present invention has a whiteness of the base paper within a predetermined range. For example, by adding a dye in the coating layer, the whiteness of the base paper and the surface of the base paper are formed. The whiteness of the coated layer surface, that is, the newsprint surface, can be leveled.

  When a dye is used for papermaking, it is generally added to a raw material pulp together with a filler for internal addition. Usually, a dye has good dyeability for pulp fibers but has low dyeability for filler. However, the dyeability of dyes for clay and calcium carbonate generally used in the past is different from the dyeability of recycled fillers.

  In the present invention, as described above, at least a specific regenerated particle aggregate is blended as a pigment in the coating agent, and the dye exhibits good dyeability with respect to the regenerated particle aggregate. In addition, the regenerated particle aggregates burned at a low temperature are more excellent in dyeability than various regenerated particle aggregates burned at a high temperature. Furthermore, the behavior of the dye also varies depending on the particle size and specifications of the pigment containing the regenerated particle aggregate.

  In addition, dyes for paper use have higher dyeability for regenerated particle aggregates than clay and calcium carbonate, which are conventionally used to exhibit anionic properties, and cationic direct dyes or basic dyes regenerate particle agglomerates. Dyeability varies depending on the specification of the collection.

  Therefore, when these dyes having different dyeing properties are used in the coating agent, the felt surface having a high dye fine fiber ratio and a filler ratio is colored with a cationic direct dye or a basic dye, and the wire surface having a high pulp ratio is mainly used. It is colored with an anionic direct dye. Therefore, by adjusting the ratio of the same color anionic direct dye and cationic direct dye or basic dye, the hue front / back difference can be reduced. Depending on the degree of adjustment, the hue front / back difference can be reduced to zero. It is also possible to do.

  In addition, by blending the dye into the coating agent and coating it on the surface of the base paper as in the present invention, it is colored with a small amount of dye compared to the case where the dye is internally added to the raw pulp as in the past. Unevenness can be suppressed.

  The type of the dye used in the present invention is not particularly limited, and one or more kinds are appropriately selected from basic dyes, acid dyes, anionic direct dyes, cationic direct dyes, nonionic dyes, etc. It can be used in combination as described above.

  Among the above dyes, anionic direct dyes have high fading, but when blended in a coating agent at the same time as a surface sizing agent or paper strength enhancer, aggregation with the surface sizing agent hardly occurs and handling is easy. Therefore, anionic starch is often used as a paper strength enhancer, and when a cationic dye is blended, an aggregate with the anionic starch may be generated. Therefore, it is more preferable to use an anionic direct dye as the dye. As described above, an anionic direct dye of the same color and a cationic direct dye or a basic dye are used in combination, and the use ratio of both is adjusted. Thus, the hue front / back difference can be reduced, and the hue front / back difference can be made zero depending on the degree of adjustment.

  Examples of the dye that can be suitably used in the present invention include the following.

(Anionic direct dye)
R1: Red anionic direct dye (manufactured by Toa Kasei Co., Ltd., registered trademark: Toa Red 2BP)
(Clariant Japan Co., Ltd., trade name: Carta Violet 3B70)
(Nippon Kayaku Co., Ltd., trade name: Kayafect Orange L)
Y1: Yellow anionic direct dye (manufactured by Toa Kasei Co., Ltd., trade name: Mikado First Yellow 21R)
B1: Blue anionic direct dye (Nippon Kayaku Co., Ltd., trade name: Direct Sky Blue 5B200)
(Nippon Kayaku Co., Ltd., trade name: Kayafect Blue RF liquid 100)

(Cationic direct dye)
R2: Red cationic direct dye (Clariant Japan Co., Ltd.,
(Product name: Cartazol Red K2BN Liquid)
(Nippon Kayaku Co., Ltd., trade name: Kayafect Orange CS)
Y2: Yellow cationic direct dye (manufactured by Clariant Japan Co., Ltd.,
Product name: Cartazol Yellow KGL Liquid)
(Nippon Chemical Industry Co., Ltd., trade name: Super Yellow YSL)
B2: Blue cationic direct dye (manufactured by Clariant Japan Co., Ltd.,
Product name: Cartazole Blue KRL Liquid)

(Basic dye)
-R3: Red basic dye (Hodogaya Chemical Co., Ltd., trade name: Astraphloxin)
・ Y3: Yellow basic dye (Nippon Chemical Industry Co., Ltd., trade name: Super Yellow FGL
-B3: Blue basic dye (BASF Japan K.K., trade name: Basazol Blue 16L)

  In the coating agent used in the present invention, in addition to the pigments and adhesives and dyes, for example, a surface sizing agent, a paper strength enhancer, an antifoaming agent, an antiseptic, and the like are commonly used in the papermaking field. An agent can be appropriately blended.

  There is no particular limitation on the method for preparing the coating agent, and the mixing ratio of pigments, adhesives, various additives, etc., if necessary, is adjusted as appropriate, and the mixture is stirred and mixed so as to obtain a uniform composition at an appropriate temperature. For example, the solid content concentration may be about 1 to 10% by mass.

  In addition, since the dye may react with other functional additives, in order to avoid such a reaction, the dye dispersed in advance should be uniformly dispersed in the coating agent immediately before the coating process. Is preferred.

  The coating agent is applied to both sides of the base paper to form a coating layer. The coating apparatus used for coating is not particularly limited. For example, a 2-roll size press, a blade metering size press, a rod metalling size press, a gate roll coater, a blade coater bar coater, a rod blade coater, an air knife coater, etc. Can be used as appropriate. Among these, a coating layer is formed by a film transfer method using a gate roll coater or a rod metering size press from the point that a coating agent can be uniformly applied to the surface of a base paper. Is preferred.

The coating amount of the coating agent when forming the coating layer is 0.2 g / m ² or more in terms of solid content on one side of the base paper in order to give sufficient surface strength to the coating layer, It is preferably 0.5 g / m ² or more. Further, in order to prevent the trouble such as sticking to the blanket and paper breakage, the solid content per side of the base paper is 3 in terms of solid content. .0g / m ² or less, and further preferably not 2.0 g / m ² or less.

  The coating speed when applying the coating agent to the base paper is not particularly limited as long as a desired coating layer is formed on both sides of the base paper, and may be about the paper making speed when manufacturing ordinary newsprint paper. That's fine.

  In the present invention, for example, using the coating apparatus, after applying the coating agent on both sides of the base paper with the coating amount, the coating layer is dried to form a coating layer. Finishing can be performed by applying a chemical treatment. In the flattening process, for example, a calendar facility such as a super calendar, a gloss calendar, or a soft calendar can be used.

  For the newsprint obtained, the surface smoothness Rp value (Parker print surf roughness (air leakage method)) of the coating layer is 1.96 MPa, for example, since the characteristics during printing such as offset color printing are further improved. For example, the flattening treatment is preferably performed so that the printing pressure is 8 μm or less, more preferably 7.5 μm or less under the printing pressure. In consideration of the instantaneous contact between the plate cylinder and the surface of the printing paper in high-speed rotary printing (the printing pressure applied to the paper is instantaneous), the surface smoothness Rp value of the coating layer is under a printing pressure of 1.96 MPa. It is preferably 4 μm or more, more preferably 4.5 μm or more.

  In addition, in this specification, the surface smoothness Rp value of a coating layer is the print surface roughness of a coating layer surface according to ISO-8791 / 4 “Paper and board-Determination of roughness / smoothness (air leak methods) -Part 4: Print. -Surf method "(1992). In this measurement, a measuring machine is a PARKER PRINT-SURF Roughness Tester Model No. manufactured by Messmer. Me-90 is used, and the conditions are soft backing and a clamping pressure of 1.96 MPa.

The newsprint of the present invention thus obtained is described in JIS P 8124 “Paper and paperboard—basis weight measurement method” in terms of weight reduction in delivery and transportation, securing of paper quality strength in high-speed rotary printing, and securing of printing opacity. The basis weight measured in accordance with the above method is 35 g / m ² or more, preferably 38 g / m ² or more. From the viewpoint of weight reduction, the basis weight is 50 g / m ² or less, preferably 48 g. / M ² or less.

  As described above, in the present invention, the whiteness of the base paper and the whiteness of the coating layer surface, that is, the newspaper paper surface are leveled, but the difference in whiteness between these two is 5% or less, Is preferably 3% or less.

Further, the newsprint of the present invention is such that L ^* , a ^* , b ^{* of} the paper surface calculated by the CIELab color space defined in JIS P 8150 is L ^* = 75.0 to 80.0,
a ^* = − 3.50 to 0.50,
b ^* = 3.50-7.50
L ^* , a ^* and b ^* on the paper surface are preferably L ^* = 77.0 to 79.0,
a ^* = − 2.50 to 0.00,
b ^* = 4.00 to 7.00
It is.

Newspapers are used for newspapers, which are information materials that cover all of the text information. If the color is excessively white, it causes eye strain. For example, in northern Japan, warm colors (red and Yellow) is preferred, and cold colors (blue and green) tend to be preferred in southern Japan. In the present invention, L ^* , a ^* , and b ^* on the paper surface are L ^* = 75.0 to 80.0, a ^* = − 3.50 to 0.50, while suitably using the regenerated particle aggregate. b ^* = 3.50 to 7.50, preferably L ^* = 77.0 to 79.0, a ^* = − 2.50 to 0.00, b ^* = 4.00 to 7.00 Thus, it is possible to provide newsprint paper that is excellent in printability without having white unevenness, high opacity, no blanket stain due to paper dust, clogging of a sword, and misregistration even though it has a coating layer.

  There is no particular limitation on the ash content of the newspaper, but for example, it is measured in accordance with the method described in JIS P 8251 “Ash Test Method” and is about 2 to 8% for the base paper, and 6 to 6 for the newspaper after coating. It is preferably about 10%.

  The regenerated particle agglomerates that can be suitably used in the present invention have moderate oil absorbency and an effect of improving opacity. Therefore, in ensuring predetermined opacity, the regenerated particle agglomerates are compared with calcium carbonate that has been conventionally used. It is possible to ensure opacity with a relatively small amount. Therefore, since it is possible to reduce the blending ratio of the filler contained in the paper, it is possible to ensure the opacity while maintaining the paper strength even in the weight reduction of the newsprint.

  Therefore, in the present invention, even when the ash content measured by the above method is about 2 to 10%, sufficient opacity can be ensured. Therefore, it is possible to provide newsprint paper that is free from clogging and misregistration and has excellent printability.

  Further, the newsprint of the present invention preferably has a printing opacity of 90% or more, more preferably 91 to 95%, from the viewpoint of appearance of printed matter and prevention of show-through.

  Next, the newspaper of the present invention will be described in more detail based on the following examples, but the present invention is not limited to these examples.

Reference Examples 1 to 10 (Production of regenerated particle aggregates)
Using deinking floss (deinking floss discharged from the flotation process of the used paper processing process for producing deinked waste paper pulp) as a raw material, dehydration under the conditions shown in Tables 1-2 according to the manufacturing equipment flow shown in FIG. The process, the first combustion process (drying / combustion process) and the second combustion process are sequentially performed. After the particles are aggregated in the second combustion process, wet pulverization is performed to obtain regenerated particle aggregates 1 to 10. .

  In Reference Examples 1-2 and 5-8, a regenerated particle aggregate was added to and dispersed in a sodium silicate solution (water glass) to prepare a slurry, and then the liquid temperature was maintained at 90 ° C. while stirring with heating. Then, dilute sulfuric acid was added to form a silica sol. Next, the pH of the final reaction solution was adjusted to 9, and silica was deposited on the surface of the regenerated particle aggregate to obtain a silica-coated regenerated particle aggregate.

  Regarding the obtained regenerated particle aggregate (and silica-coated regenerated particle aggregate), the content of calcium, silicon and aluminum (as oxide) in the particle constituents, and the total content of calcium, silicon and aluminum (oxide) Conversion), volume average particle diameter, appearance, wire wear degree, productivity and quality stability. These results are shown in Tables 3-4.

  In addition, the various measured values shown to Tables 1-4 were measured with the following method.

(A) Moisture content of dehydrated material A sample was collected and measured in accordance with the method described in JIS P 8127 “Paper and paperboard—Moisture test method—Method using a dryer”.

(I) Volume average particle size and volume distribution of dehydrated product Volume average particle size using a metal plate sieve specified in JIS Z8801-2 (2000) “Sieving for testing—Part 2: Metal plate sieve”. Was measured, and the ratio (volume distribution) of particles having a particle diameter of 50 μm or less was calculated.

(C) Oxygen concentration in the upper end of the first combustion furnace and in the vicinity of the burner of the second combustion furnace This was measured with a gas analyzer (model number: PG250 type, manufactured by Horiba, Ltd.).

(D) Unburnt rate of combusted material after the first combustion process After heating the electric muffle furnace to 600 ° C in advance, put the sample in a crucible and burn it completely in about 3 hours. Was calculated.

(E) Content of calcium, silicon and aluminum in the regenerated particle aggregate (as oxide)
After forming a coating layer on the front and back surfaces of the base paper as in the examples shown below, 100 regenerated particle aggregates scattered on the surface of the coating layer were randomly extracted, and X-ray microscopy was performed on each aggregate. Elemental analysis of the particle constituents was performed with an analyzer (model number: E-MAX · S-2150, manufactured by Hitachi, Ltd./manufactured by Horiba, Ltd.) to obtain an average value. Further, the total content ratio (calculated in terms of oxide) of calcium, silicon, and aluminum in the particle constituents of the regenerated particle aggregate was calculated from the contents of these calcium, silicon, and aluminum.

(F) Volume average particle diameter of regenerated particle aggregate (volume average particle diameter at the inlet and volume average particle diameter at the outlet in Table 2, and volume average particle diameter in Table 3)
A 10 mg sample of the regenerated particle aggregate was dispersed with an ultrasonic disperser (output: 80 W) for 3 minutes. Using this, the average particle size was measured with a laser particle size distribution measuring device (laser diffraction type particle size distribution measuring device SALD-2200, measured with standard refractive index (1), manufactured by Shimadzu Corporation).

(G) Appearance The color of the regenerated particle aggregate was visually observed and divided into white and gray.

(H) Degree of wire wear Using a wear degree test apparatus (manufactured by Nippon Filcon Co., Ltd.), the degree of wear of the plastic wire was measured for 3 hours at a slurry concentration of 2% by mass.

(I) Productivity Each of the raw material dehydration efficiency, productivity, and electric power required for pulverization was evaluated in five stages, and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: All were highly evaluated and the balance was the best.
○: The evaluation may be averaged.
(Triangle | delta): There existed a problem in either the dehydration efficiency, productivity, and the electric power required for a grinding | pulverization.
X: Actual operation was difficult.

(G) Quality stability The degree of variation was measured for each item of whiteness, particle diameter, and production volume at a fixed time interval, and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: No change was found in any item.
○: There was almost no change in any of the items.
Δ: Variation was observed in any of the items.
X: Variation was observed in all items.

  From the results shown in Table 4, it can be seen that the regenerated particle aggregates of Reference Examples 1 to 10 each have high whiteness, low wire wear, and excellent productivity and quality stability. .

Production Examples 1 to 20 (Preparation of base paper)
As raw material pulp, bleached pressed stone ground pulp (BPGW), softwood bleached kraft pulp (NBKP), hardwood bleached kraft pulp (LBKP) and deinked waste paper pulp manufactured from newspaper waste paper (DIP, mechanical pulp content: 30% by mass) ) Were mixed at a ratio shown in Table 5 to obtain a pulp slurry. To this pulp slurry, a sizing agent (product name: CS-1700, manufactured by Seiko PMC Co., Ltd.) is added in an amount of 0.05 parts by mass based on 100 parts by mass of pulp solids, and a long net paper machine is used. A base paper having a basis weight of about 35 to 47 g / m ² was obtained.

  The whiteness of the base paper was measured according to JIS P 8148: 2001. The results are also shown in Table 5.

Preparation Examples 1-10 and Comparative Preparation Examples 1-10 (Preparation of coating agent)
After stirring and mixing each component shown in Tables 6 to 7 at room temperature until a uniform composition is obtained, the mixture is diluted with purified water, and the coating agent 1 to 10 having a solid concentration of about 40% by mass and the comparative coating agent. 1-10 were prepared. In addition, about the dye shown to Tables 6-7, what was disperse | distributed beforehand is used by disperse | distributing uniformly to a coating agent just before the coating process in Examples 1-10 and Comparative Examples 1-10 shown below. It was. Moreover, the ratio of each dye was suitably adjusted according to the color.

  In addition, the pigments, adhesives, and dyes shown in Tables 6 to 7 are as follows.

(Pigment)
Kaolin: Kaolin clay from Brazil: Delaminated clay grade 1: grade 1 clay grade 2: grade 2 clay white: white carbon

(adhesive)
PVA: average polymerization degree 1700, saponification degree 98-99 mol%
(Product name: PVA117, manufactured by Kuraray Co., Ltd.)
SBR: Styrene butadiene rubber latex (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)

(dye)
R1: Red anionic direct dye (Nippon Kayaku Co., Ltd., trade name: Kayafect Orange L)
Y1: Yellow anionic direct dye (manufactured by Toa Kasei Co., Ltd., trade name: Mikado First Yellow 21R)
B1: Blue anionic direct dye (manufactured by Nippon Kayaku Co., Ltd., trade name: Kayafect Blue RF liquid 100)
R2: Red cationic direct dye (Nippon Kayaku Co., Ltd., trade name: Kayafect Orange CS)
Y2: Yellow cationic direct dye (Nippon Chemical Industry Co., Ltd., trade name: Super Yellow YSL)
B2: Blue cationic direct dye (manufactured by Clariant Japan Co., Ltd.,
Product name: Cartazole Blue KRL Liquid)
R3: Red basic dye (Hodogaya Chemical Co., Ltd., trade name: Astraphloxin)
Y3: Yellow basic dye (manufactured by Nippon Chemical Industry Co., Ltd., trade name: Super Yellow FGL
B3: Blue basic dye (manufactured by BASF Japan Ltd., trade name: Basazol Blue 16L)

Examples 1-10 and Comparative Examples 1-10 (Manufacture of newsprint)
Apply the coating agent on the front and back surfaces of the base paper with the coating equipment shown in Table 8 so that the coating amount (solid content) per one side of the base paper is the amount shown in Table 8. After being worked, it was dried to form a coating layer. The coating amount on the front and back surfaces was adjusted to be the same. This was subjected to a flattening treatment with a soft calender, and newspaper paper was obtained so that the surface smoothness Rp value of the coating layer measured by the method shown below would be the value shown in Table 8.

  In addition, the coating apparatus shown in Table 8 is as follows.

Gate roll: Gate roll coater Rod metal ring: Rod metal ring size press 2 roll: 2 roll size press

  Each physical property of the obtained newspaper was measured by the following method. These results are shown in Tables 9-12. Moreover, about the coating layer of the obtained newsprint paper surface, the existence area (area ratio) of the regenerated particle aggregate (Reference Examples 1 to 10) and the total existence area (area ratio) of the regenerated particle aggregate and the high aspect pigment (Preparation Examples 1 to 10) were also measured. These results are shown together in Table 10.

(A) Regenerated particle aggregate existing area (area ratio)
On the surface of the coating layer, 10 areas of a sample with a constant area of 12000 times were photographed, and elemental analysis was performed in each area using the same X-ray microanalyzer as described above, and an image analysis apparatus (model number: Luzex, ( The part detected by overlapping calcium, silicon and aluminum is selected as a regenerated particle aggregate, and the area ratio of the part detected by overlapping calcium, silicon and aluminum is calculated with an image analyzer. did.

(B) Total existence area (area ratio) of regenerated particle aggregate and high aspect pigment
On the surface of the coating layer, 10 areas of a sample with a constant area of 12000 times were photographed, elemental analysis was performed in each area with the same X-ray microanalyzer, and calcium was analyzed with the same image analysis apparatus as above. The area (A) detected by overlapping silicon and aluminum was measured, and the area calculated by multiplying the number of high aspect pigments visually recognized by an X-ray microanalyzer by the average area of 10 high aspect pigments ( B) was measured, and the total area ratio was calculated from the area (A) and the area (B).

(C) Presence region (area ratio) of pigment used in comparative preparation example
On the surface of the coating layer, 10 areas of a sample with a constant area at 12000 times were photographed, and with the same X-ray microanalyzer as above, silicon alone was used for white carbon, and silicon and magnesium for talc. The area detected by overlapping with each other was measured, the area calculated by multiplying the average area of 10 pigments according to the number of pigments used in Comparative Preparation Example visually recognized was measured, and the total area ratio was calculated.

(D) Surface smoothness Rp value of coating layer It was measured in accordance with ISO-8791 / 4 (1992) with a print surface roughness which is a smoothness tester due to air leakage. The measuring machine is a PARKER PRINT-SURF Roughness Tester Model No. manufactured by Messmer. Using Me-90, measurement was performed under conditions of soft backing and a clamping pressure of 1.96 MPa.

(E) Basis weight Measured according to JIS P 8124.

(F) Whiteness Measured according to JIS P 8148 (2001).

(G) Whiteness difference The difference between the whiteness of newsprint base paper and the whiteness of the coated surface after coating was determined and expressed as an absolute value.

(H) L ^* , a ^* , b ^*
Calculation was performed according to the CIELab color space defined in JIS P 8150. As a measuring device, a color analyzer “i5” (SCE method, viewing angle 2 °, light source: CIE illuminant C) manufactured by Macbeth Co. was used.

(I) Ash content It measured based on JISP8251.

(J) Opacity of printing Offset rotary printing press (model: RI-2, manufactured by Ishikawajima Industrial Machinery Co., Ltd.), offset rotary printing ink (trade name: News Zet Naturalis (black), Dainippon Ink & Chemicals, Inc. The ratio of the back-surface reflectance after printing to the back-surface reflectance before printing when the printing surface reflectance is 9% when changing the ink amount of (made by Co., Ltd.):
(Back side reflectance after printing / Back side reflectance before printing) × 100 (%)
Asked. A spectral whiteness colorimeter (manufactured by Suga Test Instruments Co., Ltd.) was used for measuring the reflectance.

  Next, each characteristic was investigated about each newsprint based on the following test examples 1-5. The results are shown in Tables 9-10.

Test example 1 (ink absorption unevenness)
Using an offset color printer (model number: SYSTEM C-20, manufactured by Komori Corporation), four-color printing was performed in the order of indigo, red, yellow, and black at a printing speed of 160,000 copies / hour. The ink density unevenness of the deep blue / red color portion was visually observed and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: Ink density unevenness is not recognized at all, and the image is uniform and clear.
○: Ink density unevenness is hardly recognized, and the image is uniform.
Δ: Ink density unevenness is recognized and the image is slightly non-uniform.
X: Ink density unevenness is obvious and the image is non-uniform.
Of the above evaluation criteria, the cases of ○ and ○ are judged to be actually usable.

Test Example 2 (Paper dust accumulation on blanket)
Using the same offset color printing machine as in Test Example 1, four-color printing was performed in the order of indigo, red, yellow, and black at the same printing speed. After printing 5000 parts, the degree of paper powder accumulation on the blanket non-image area was visually observed and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: Generation of paper dust is not recognized.
○: Slight generation of paper dust is observed, but there is no practical problem.
Δ: The occurrence of paper dust is clearly recognized.
X: A lot of paper dust is accumulated on the blanket, and the blanket is white.
Of the above evaluation criteria, the cases of ○ and ○ are judged to be actually usable.

Test Example 3 (Color printing suitability)
Using an offset rotary press (model number: DIAMONDSTAR, manufactured by Mitsubishi Heavy Industries, Ltd.), four-color printing was performed in the order of indigo, red, yellow, and black at a printing speed of 150,000 copies / hour. The print surface density and density unevenness of the fourth black single color part and the uniformity of the printed image of the heavy color part where the four colors were superimposed were visually observed and evaluated based on the following evaluation criteria.
(Evaluation criteria)
(Double-circle): The printing surface density | concentration of a black monochrome part is very high, and there is no density nonuniformity. In addition, a very uniform image is obtained in the heavy color area.
◯: The printed surface density of the black single color portion is high and there is almost no density unevenness. In addition, a uniform image is obtained in the heavy color area.
(Triangle | delta): The printing surface density | concentration of a black monochrome part is a little low, and a density nonuniformity is recognized. In the heavy-colored area, an image that is uneven and slightly sharp is obtained.
X: The printing surface density of the black monochrome portion is low, and density unevenness is clearly recognized. In the heavy color area, an image that is uneven and lacks clarity is obtained.
Of the above evaluation criteria, the cases of ○ and ○ are judged to be actually usable.

Test example 4 (number of blade clogs)
Using a newspaper offset rotary press (model number: DIAMONDSTAR, manufactured by Mitsubishi Heavy Industries, Ltd.), printing was performed at a printing speed of 150,000 copies per hour, and the number of times the sword clog occurred at the folded portion during 6 hours. It was measured.
In addition, it is determined that actual use is possible when the number of occurrences of sword clogging is one or less.

Test Example 5 (Register misalignment)
Using the same newspaper offset rotary press as in Test Example 4, four-color printing was performed in the order of indigo, red, yellow, and black at a printing speed of 120,000 copies per hour. The difference in the width direction of the registration mark position between the first color and the fourth color was measured immediately before the paster (automatic paper splicing) and at the 100th copy after the paster, respectively, and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: The difference between before and after the paster is less than 0.1 mm.
○: The difference between before and after the paster is 0.1 mm or more and less than 0.2 mm.
(Triangle | delta): The difference before and behind a paster is 0.2 mm or more and less than 0.3 mm.
X: The difference before and after the paster is 0.3 mm or more.
Of the above evaluation criteria, the cases of ○ and ○ are judged to be actually usable.

In all the newsprints of Examples 1 to 10, the whiteness of the base paper is within an appropriate predetermined range, and the surface of the base paper is coated with a coating agent in which specific recycled particle aggregates are blended as pigments. A layer is formed, and L ^* , a ^* , and b ^{* of} the surface thereof are each adjusted within a predetermined range. Therefore, the newsprint papers of Examples 1 to 10 are not only lightweight, but also have a coating layer and have little white unevenness, high opacity, blanket stains due to paper dust, clogging of the sword and registration. It can be seen that there is no misalignment and excellent color printing aptitude, and the characteristics are very suitable for offset printing such as high-speed offset color printing.

On the other hand, none of the newspapers of Comparative Examples 1 to 10 uses a regenerated particle aggregate as a pigment contained in the coating layer, ink absorption unevenness, accumulation of paper powder on the blanket, claw tip clogging, It can be seen that it does not have characteristics necessary for offset printing, such as high-speed offset color printing, such as significant misregistration and poor color printing suitability.

  The newsprint of the present invention can be suitably used for offset printing such as offset color printing at a high speed of, for example, 170 to 200,000 copies / hour, particularly high-definition printing in high-speed offset full-color printing.

Schematic showing a partial configuration example of the production facility flow of recycled particle aggregates It is the partial schematic of a 2nd combustion furnace, (a) is a partially broken schematic sectional drawing of a 2nd combustion furnace, (b) is an internal expansion schematic plan view of a 2nd combustion furnace.

Explanation of symbols

10 Raw material 14 First combustion furnace 32 Second combustion furnace

Claims (2)

A method for producing newsprint, in which a coating layer is formed of a coating agent mainly composed of a pigment and an adhesive and colored with a dye on at least one side of a base paper,
As the pigment, the deinking floss discharged in the deinking process of the used paper processing process for producing the used paper pulp is used as a main raw material, through the dehydration process, the drying process, the combustion process and the pulverization process, without the carbonization process, At least the regenerated particle agglomerates that are aggregates in the combustion process are blended, the combustion process is at least two-stage combustion, and the furnace temperature (combustion temperature) of the first combustion furnace in the combustion process is 300 ° C. or more and 500 ° C. Is less than
The whiteness of the base paper measured in accordance with JIS P 8148 is 52-60%,
The whiteness difference of the base paper and the whiteness of the coating layer surface, that is, the newspaper paper surface is 1.1% or less,
L *, a *, and b * of the paper surface calculated by the CIELab color space defined in JIS P 8150 are L * = 75.0 to 80.0,
a * = − 3.50 to 0.50,
b * = 3.50-7.50
A method for producing newsprint, characterized in that: Newspaper paper on which at least one side of a base paper has a coating layer formed of a coating agent mainly composed of a pigment and an adhesive and colored with a dye,
As the pigment, the deinking floss discharged in the deinking process of the used paper processing process for producing the used paper pulp is used as a main raw material, through the dehydration process, the drying process, the combustion process and the pulverization process, without the carbonization process, At least the regenerated particle agglomerates that are aggregates in the combustion process are blended, the combustion process is at least two-stage combustion, and the furnace temperature (combustion temperature) of the first combustion furnace in the combustion process is 300 ° C. or more and 500 ° C. Is less than
The whiteness of the base paper measured in accordance with JIS P 8148 is 52-60%,
And whiteness of the base paper, coating layer surface, i.e. the whiteness difference of 1.1% or less of newsprint surface,
L *, a *, and b * of the paper surface calculated by the CIELab color space defined in JIS P 8150 are L * = 75.0 to 80.0,
a * = − 3.50 to 0.50,
b * = 3.50-7.50
Newspaper paper obtained by manufacturing to become .

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