JP2010236099A - Method for producing paper and paperboard containing papermaking sludge - Google Patents

Abstract

The present invention provides a paper or paperboard manufacturing method in which the yield of papermaking sludge and wastewater sludge is increased so that papermaking sludge and wastewater sludge that have not been used in the papermaking industry can be reused as papermaking raw materials.
A method for producing paper or paperboard, comprising:
(A) Paper sludge is blended in and mixed with pulp slurry, (b) an enzyme composition containing a cellulolytic enzyme, preferably cellulase and / or hemicellulase is added, (c) beating treatment is performed, (d) paper Or make paperboard.
[Selection figure] None

Description

  The present invention relates to a method for producing paper and paperboard containing papermaking sludge. More particularly, the present invention relates to a method for improving the yield of papermaking sludge in order to reuse papermaking sludge as a papermaking raw material.

  In recent years, the reuse of waste paper has been increasing from the standpoint of resource saving, energy saving, and pollution prevention, and the reuse is increasingly promoted. For example, in order to produce corrugated cardboard, it is more frequently used to collect and recycle fibers as raw materials, and the quality of the raw materials decreases with every collection and recycling. Therefore, in order to obtain a sufficient mechanical property level, pulp refining (beating) is generally performed. On the other hand, the paper sludge discharged from the paper making process and the waste water treatment process along with recycling, or the treatment of waste water sludge has been an issue. Papermaking sludge mainly contains chemical substances and organic substances such as fine fibers and fillers, hemicellulose, starch, rosin, potash alum, hot melt (usually called sticky substances and sticky substances). Conventionally, papermaking sludge has been treated by incineration or landfilling, but in recent years, its use as a part of papermaking raw materials has been promoted.

  When paper or paperboard is produced by blending papermaking sludge with pulp as a papermaking raw material, the yield is low due to its fineness, and paper quality is reduced and paper strength is reduced unless it is uniformly dispersed in the pulp slurry. . Further, the drainage of the pulp slurry is lowered, and there is an obstacle to the operation due to a decrease in paper making speed and a decrease in drying speed. Therefore, various improvement measures have been proposed. For example, a paper sludge is sequentially treated with a cellulolytic enzyme, a cationic polymer, and an anionic polymer (Patent Document 1), a paper sludge is treated with an enzyme, and then mixed with pulp to make paper or paperboard (patent) Reference 2). However, no paper and paperboard manufacturing method has yet been obtained that provides a sufficiently satisfactory yield of papermaking sludge.

Japanese Patent Laid-Open No. 8-92889 JP 2005-536648 A

  The papermaking sludge generated in the paper and paperboard manufacturing process mainly contains fine fibers and fillers, as well as impurities in the papermaking raw material and pulp-derived resin, etc., which are blended with pulp as a papermaking raw material to make paper or paperboard When manufacturing, there are obstacles such as a decrease in drainage of pulp slurry, a decrease in paper making speed, and a decrease in paper strength. The present invention provides an efficient and effective method for producing paper and paperboard, which eliminates the above-mentioned obstacles and promotes the use of papermaking sludge as a papermaking raw material in the production of paper and paperboard containing papermaking sludge. It is to provide.

  In order to solve the above-mentioned problems, the present inventors have intensively studied on a method for producing paper and paperboard mixed with papermaking sludge. As a result, papermaking sludge is blended with pulp slurry to perform enzyme treatment, beating treatment, and papermaking. Has found that uniform dispersion and fixing of papermaking sludge in the pulp slurry can be obtained, and the present invention has been completed.

  That is, the present invention is a method for producing paper or paperboard, wherein (a) paper sludge is blended and mixed with pulp slurry, (b) an enzyme composition containing cellulolytic enzyme is added, and (c) beating treatment And (d) a paper or paperboard manufacturing method characterized in that paper or paperboard is made. The cellulolytic enzyme is preferably cellulase and / or hemicellulase, and the hemicellulase is more preferably xylanase. Moreover, the effect of this invention is exhibited more because an enzyme composition contains a cellulase, a hemicellulase, and an esterase.

  The pulp slurry in the paper or paperboard production method of the present invention is not particularly limited as long as it is a pulp that is a raw material used in the production of paper or paperboard. For example, hardwood kraft pulp (LKP) and its bleached product ( LBKP), softwood kraft pulp (NKP) and its bleached product (NBKP), grind pulp (GP), thermomechanical pulp (TMP), recovered waste paper such as newspapers, magazines and flyers, deinked waste paper, corrugated waste paper, etc. It is done. One or more of these are used. Although the density | concentration of a pulp slurry is not specifically limited, Usually, 1 to 20 weight%, Preferably it is 2 to 10 weight%.

  The papermaking sludge used in the present invention is pulp or fine fiber in all paper or paperboard manufacturing processes from used paper / waste paper recovery process, disaggregation process to papermaking process, and final winding process in the manufacture of paper or paperboard. And the like. Separation removal products and filtration separation products containing raw materials used in the manufacture of paper or paperboard. For example, unbeaten that has been separated and removed by filtration and separation of screens and cleaners for used paper / waste paper recovery process, disaggregation process and selection process, cleaner and thickener for preparation process and papermaking process, and polydisc filter and thickener for white water recovery process Pulp, fine fibers, fillers (eg clay, talc, calcium carbonate, bentonite, silica, etc.), sticky organic substances such as pitch and hot melt, starch and processed or modified products thereof, sizing agents such as rosin, inorganic system in the process Scales (for example, silica, calcium silicate, aluminum silicate, calcium carbonate, barium sulfate, etc.) and mixtures thereof can be mentioned.

  The pulp slurry and papermaking sludge in the present invention are blended and mixed before the pulp beating process. The mixing location is not particularly limited. For example, when using waste paper, the waste paper is disaggregated with a pulper, and impurities are removed with a cleaner. Then, the obtained pulp slurry is put into a storage chest, and the paper sludge is stirred. Are added and mixed to obtain a pulp slurry containing papermaking sludge. The blending amount of the papermaking sludge is not particularly limited, but is usually blended with 0.5% to 20% (vs. pulp) as a guide.

  After blending and mixing paper sludge with the pulp slurry, the enzyme composition is added before the beating treatment. As long as the enzyme composition is added to the pulp slurry blended with papermaking sludge, the addition and mixing location is not particularly limited as long as it is before the beating treatment. For example, the pulp slurry is put in a storage chest, and after stirring, paper sludge is added and mixed to obtain a pulp slurry containing the paper sludge, and then the enzyme composition may be added and mixed under stirring.

  The pulp slurry containing the papermaking sludge and the enzyme composition is beaten by a beating machine. A refiner is generally used as a beater, and there are a single disc refiner, a double disc refiner, a conical refiner, and the like. The pulp slurry containing the enzyme composition is subjected to a beating treatment, whereby the pulp is fibrillated by the action of the enzyme to improve paper strength, and the papermaking sludge is retained between the fibrillated pulp and the yield is increased. improves. By improving the yield of papermaking sludge, papermaking sludge in white water is reduced, the COD load of white water is reduced, and the wastewater treatment burden is also reduced.

  After beating the pulp slurry containing the papermaking sludge and enzyme composition, various additives (for example, filler, sizing agent, drainage improver, etc.) are added to the pulp to prepare paper stock. Paper or paperboard is made using a paper machine.

  The enzyme composition in the present invention is an enzyme containing at least one cellulolytic enzyme. Cellulose-degrading enzymes in the present invention are cellulase and hemicellulase. Examples of hemicellulase include xylanase, lactase, galactanase, mannanase, and arabinase, and xylanase is preferable.

  The enzyme composition preferably contains cellulase, hemicellulase, and esterase as cellulolytic enzymes. By using cellulase, hemicellulase and esterase in combination, an unexpectedly high beating-promoting effect can be obtained. The esterase used in the present invention is an enzyme that degrades ester bonds, and degrades relatively long-chain higher fatty acid esters such as lipase and ferulic acid esterase, which are non-specific esterases that degrade relatively short-chain lower fatty acid esters. Specific esterase lipases, cholinesterases, acetylcholinesterases, and the like. Of these, lipases that decompose lower fatty acid esters, ferulic acid esterases, and the like are preferable. As specific esterases, lipase includes lipase A “Amano” (trade name, manufactured by Amano Enzyme Co., Ltd.), lipase (trade name, manufactured by Nagase Chemtech Co., Ltd.), and ferulic acid esterase includes ferulic acid. Esterase (reagent), pectinase PL “Amano” (trade name, Amano Enzyme Co., Ltd .: pectinase PL “Amano” contains ferulic acid esterase as of September 30, 2007, Osaka Prefecture University, Described in “Research on Enzymatic Synthesis of Water-soluble Ester Derivatives of Cinnamic Acids”). One or more of these esterases may be used in combination.

  The ratio of esterase to cellulase and hemicellulase is not particularly limited, but the weight ratio is “esterase”: “total amount of cellulase and hemicellulase” = 5: 1 to 1: 5. Similarly, the ratio of cellulase to hemicellulase is “cellulase”: “hemicellulase” = 5: 1 to 1: 5. Specific cellulases include Meiji Cellulase TP (trade name, manufactured by Meiji Seika Co., Ltd.), Cell riser (trade name, manufactured by Nagase Chemtech Co., Ltd.), Cell Crust (trade name, manufactured by Novozymes Japan Co., Ltd.) ), Cellzyme (trade name, manufactured by Novozymes Japan), Cellulase A “Amano” (trade name, manufactured by Amano Enzyme), Cellulase T “Amano” (trade name, manufactured by Amano Enzyme), Examples of hemicellulase include hemicellulase “Amano” (trade name, manufactured by Amano Enzyme Co., Ltd.), pulpzyme HC (trade name, manufactured by Novozymes Japan Co., Ltd.) (xylanase which is a kind of hemicellulase), and the like. Furthermore, as an enzyme containing cellulase and hemicellulase, Sumiteam AC (trade name, manufactured by Shinnippon Chemical Co., Ltd.), Sumiteam C (trade name, manufactured by Shinnippon Chemical Co., Ltd.), Hakufina BR-100 (trade name) Hakufina BR-300 (trade name, manufactured by Hakuto Co., Ltd.) and the like. Among them, the enzyme composition obtained from the separated culture of Chrysosporium lachnowens garg 27K (deposit number VKMF-3500D) contains cellulase, hemicellulase and ferulic acid esterase, and is more preferable because the effects of the present invention are more exhibited. One or more of these cellulases, hemicellulases, or enzymes including cellulases and hemicellulases may be used in combination. In addition, cellulose fiber components such as pectinase and protease and enzymes capable of decomposing other than esters may be included. The enzyme used in the method of the present invention can be obtained either in the form of a powder or in the form of a solution in consideration of the route of availability and the stability of the enzyme. Well, not particularly limited.

  In the enzyme treatment of the present invention, the enzyme composition in powder form is diluted with water and used as an enzyme solution, and the enzyme composition in liquid form is used as it is, or diluted with water and enzyme solution. It is preferable to use as. The enzyme treatment in the present invention is performed by adding an enzyme solution to a pulp slurry containing papermaking sludge. In the present invention, the effect of the invention is exhibited by adding an enzyme composition, and the amount added cannot be determined uniformly, but usually 0.005 to 2 per pulp weight as cellulase or hemicellulase. %, Preferably 0.02 to 1%. When cellulase and hemicellulase are used in combination, the total amount of cellulase and hemicellulase is 0.005 to 2%, preferably 0.02 to 1% per pulp weight. When esterase is used in combination, cellulase and esterase combination, hemicellulase and esterase combination, cellulase and hemicellulase and esterase combination, the amount of cellulase alone or hemicellulase alone, and the total amount of cellulase and hemicellulase per pulp weight If it is 0.005 to 2%, preferably 0.02 to 1%, a synergistic effect is exhibited when the esterase is 0.001% or more. Moreover, even if 2% or more of the enzyme composition is added, the improvement in the disaggregation promoting effect corresponding to the amount of enzyme added is small, which is disadvantageous in terms of cost.

  The enzyme solution in the present invention is recovered as a filtrate in the concentration step after the enzyme treatment step, and is reused by returning the filtrate to the enzyme treatment step. As for the reuse of the enzyme treatment solution, a new enzyme treatment solution may be added by the amount lost in the recovery when the enzyme treatment solution is reused. Therefore, since the method of the present invention can reuse an enzyme solution, there are few concerns about environmental pollution such as water pollution, and there are advantages such as energy saving and cost reduction of chemicals and wastewater treatment.

  It is desirable to adjust the temperature and pH during the enzyme treatment to the optimum temperature and pH of the enzyme as long as the enzyme used is not inactivated. In general, the temperature of the enzyme treatment solution is 20 to 70 ° C, preferably 40 to 60 ° C, and the pH is 3.0 to 8.0, preferably 4.0 to 6.5.

  The enzyme treatment time cannot be uniformly determined depending on the enzyme used, the type of the target pulp or paper, the pH of the enzyme treatment solution, etc., but is usually 0.5 to 10 hours.

  According to the method of the present invention, paper and paperboard can be produced by reusing papermaking sludge generated in the paper and paperboard production process as a papermaking raw material without reducing paper strength, and there is a concern about environmental pollution such as water pollution. In addition, there are merits such as energy saving and cost reduction of chemicals and wastewater treatment.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Moreover, all the% in each Example is weight%, and the density | concentration of a pulp slurry points out the density | concentration of the pulp derived from waste paper.

Example 1
Papermaking by enzyme treatment using paperboard sludge (35% solid content: including fine fibers, calcium carbonate, talc, clay, calcium silicate, etc.) generated from the corrugated waste paper and the polydisc filter in the white water recovery process during its production The yield improvement of sludge and the paper strength improvement test of the paper which mix | blended papermaking sludge were done.
(1) Preparation of paper stock In accordance with JISP8220-1998, 150 g of waste corrugated paper as a completely dry weight and 5 L of water were put into a disaggregator and disaggregated for 10 minutes to prepare a 3% pulp slurry. Next, paper sludge was added as a paper sludge solid content by 10% (vs. pulp) and stirred, and then used as a test paper stock.
(2) Enzyme treatment 1,000 g of test paper stock is placed in a 2,000 ml beaker and maintained at 40 ° C. with stirring, 0.01% cellulase A “Amano” (trade name, manufactured by Amano Enzyme) aqueous solution: 15 ml And the enzyme treatment was performed for 1 hour. After enzyme treatment, the freeness of 3% pulp slurry blended with paper sludge was measured according to JISP 8121-1995 as Canadian standard freeness (CSF ml). The freeness of the 3% pulp slurry with papermaking sludge was 452 ml.
(3) Beating treatment An enzyme-treated papermaking sludge-containing 3% pulp slurry was No. The solution was suction filtered with 1 filter paper and a Buchner funnel, concentrated to 10% pulp slurry containing paper sludge, and 300 g of the pulp slurry was placed in a PFI mill and beaten at 5000 revolutions. The freeness (CSF) of the pulp slurry containing the papermaking sludge after the beating treatment was measured according to JISP 8121-1995. Pulp slurry freeness (CSF) is a measure of beating, and the higher the degree of beating, the greater the decrease in freeness before and after beating, and the more fibrillation of the pulp progressed. At the same time, the turbidity of the filtrate was measured with an integrating sphere turbidimeter.
(4) Preparation and evaluation of handmade paper sheet Next, the pulp slurry containing the papermaking sludge after the beating treatment is diluted with water to prepare an approximately 0.5% pulp slurry, and the basis weight is 60 g / m ² according to JISP8222-1998. A handsheet was prepared. The burst strength was measured according to JISP8112-1994 using the prepared handsheet, and the specific burst strength was calculated. The higher the specific burst strength, the more the pulp was beaten. The results are shown in Table 1.

(Example 2)
In Example 1, instead of 15 ml of 0.01% cellulase A “Amano” aqueous solution, 60 ml of 0.01% cellulase A “Amano” aqueous solution was added to carry out the enzyme treatment. Force measurements were taken.

Example 3
In Example 1, in place of 15 ml of 0.01% cellulase A “Amano” aqueous solution, 90 ml of 0.01% cellulase A “Amano” aqueous solution was added to carry out the enzyme treatment. Force measurements were taken.

Example 4
In Example 1, 0.01% cellulase A “Amano” aqueous solution: In place of 15 ml, 30 ml of 1% cellulase A “Amano” aqueous solution was added for enzyme treatment, and then hand-sheet preparation and paper strength were similarly performed. Measurements were made.

(Example 5)
In Example 1, instead of 15 ml of 0.01% cellulase A “Amano” aqueous solution, 60 ml of 1% cellulase A “Amano” aqueous solution was added to carry out the enzyme treatment. Went.

(Example 6)
In Example 1, instead of 15 ml of 0.01% cellulase A “Amano” aqueous solution, 60 ml of 0.01% hemicellulase “Amano” (trade name, manufactured by Amano Enzyme Co., Ltd.) aqueous solution was added to perform enzyme treatment. Thereafter, hand-sheet preparation and paper strength measurement were performed in the same manner.

(Example 7)
In Example 3, instead of 90 ml of 0.01% cellulase A “Amano” aqueous solution, 15 ml of 0.01% cellulase A “Amano” aqueous solution and 75 ml of 0.01% hemicellulase “Amano” aqueous solution were added for enzyme treatment. Thereafter, hand-sheet preparation and paper strength measurement were performed in the same manner.

(Example 8)
In Example 3, instead of 90 ml of 0.01% cellulase A “Amano” aqueous solution, 45 ml of 0.01% cellulase A “Amano” aqueous solution and 45 ml of 0.01% hemicellulase “Amano” aqueous solution were added for enzyme treatment. Thereafter, hand-sheet preparation and paper strength measurement were performed in the same manner.

Example 9
In Example 3, instead of 90 ml of 0.01% cellulase A “Amano” aqueous solution, 75 ml of 0.01% cellulase A “Amano” aqueous solution and 15 ml of 0.01% hemicellulase “Amano” aqueous solution were added to perform enzyme treatment. Thereafter, hand-sheet preparation and paper strength measurement were performed in the same manner.

(Example 10)
In Example 7, instead of 75 ml of 0.01% hemicellulase “Amano” aqueous solution, 3 ml of 0.01% lipase A “Amano” (trade name, manufactured by Amano Enzyme) aqueous solution was added to perform enzyme treatment. Thereafter, hand-sheet preparation and paper strength measurement were performed in the same manner.

(Example 11)
In Example 10, in place of 3 ml of 0.01% lipase A “Amano” (trade name, manufactured by Amano Enzyme), 3 ml of 0.01% ferulic acid esterase (reagent) aqueous solution was added for enzyme treatment. Thereafter, hand-sheet preparation and paper strength measurement were performed in the same manner.

(Example 12)
In Example 1, instead of 15 ml of 0.01% cellulase A “Amano” aqueous solution, 15 ml of 0.01% cellulase A “Amano” aqueous solution, 15 ml of 0.01% hemicellulase “Amano” aqueous solution and 0.1% lipase A Dissolution was carried out by adding 15 ml of an “Amano” aqueous solution. Then, the enzyme treatment was carried out, and then hand-sheets were prepared and the paper strength was measured in the same manner.

(Example 13)
In Example 12, instead of 15 ml of 0.01% cellulase A “Amano” aqueous solution, 15 ml of 0.01% hemicellulase “Amano” aqueous solution and 15 ml of 0.1% lipase A “Amano” aqueous solution, 0.01% cellulase A 45 ml of “Amano” aqueous solution, 45 ml of 0.01% hemicellulase “Amano” aqueous solution and 18 ml of 0.01% lipase A “Amano” aqueous solution were added to carry out the enzyme treatment, and then hand-sheet preparation and paper strength Measurements were made.

(Example 14)
In Example 13, instead of 45 ml of 0.01% hemicellulase A “Amano” aqueous solution, 45 ml of 0.01% pulpzyme HC (trade name, manufactured by Novozymes Japan) aqueous solution as xylanase was added to perform enzyme treatment. After that, handsheets were prepared and paper strength was measured in the same manner.

(Comparative Example 1)
In Example 1, hand-sheet preparation and paper strength measurement were performed without performing enzyme treatment and beating treatment.

(Comparative Example 2)
In Comparative Example 1, the beating process was performed without performing the enzyme process, and then hand-sheet preparation and paper strength measurement were performed in the same manner.

(Comparative Example 3)
3% pulp slurry with paper sludge blended is suction filtered with No1 filter paper and Buchner funnel and concentrated to 10% pulp slurry with paper sludge blended. I did it. The Canadian standard freeness (CSF ml) of the pulp slurry blended with papermaking sludge after the beating treatment was measured according to JISP 8121-1995. At the same time, the turbidity of the filtrate was measured with an integrating sphere turbidimeter. The pulp containing the paper sludge after the beating treatment is diluted with pure water to make 400% of 2% pulp slurry, kept at 40 ° C., and with stirring, 16 ml of 1% cellulase A “Amano” aqueous solution (cellulase added amount 2% (vs. Pulp)) was added to carry out the enzyme treatment. After the enzyme treatment, it was prepared into a pulp slurry of about 0.5% with water, and a handsheet having a basis weight of 60 g / m ² was prepared according to JISP8222-1998. The burst strength was measured according to JISP8112-1994 using the prepared handsheet, and the specific burst strength was calculated.

(Comparative Example 4)
In Comparative Example 3, instead of 16 ml of 1% cellulase A “Amano” aqueous solution, 16 ml of 1% hemicellulase “Amano” aqueous solution was added and the enzyme treatment was carried out in the same manner to prepare a handsheet and measure paper strength. .

(Comparative Example 5)
In Comparative Example 3, instead of 16 ml of 1% cellulase A “Amano” aqueous solution, 8 ml of 1% cellulase A “Amano” aqueous solution and 8 ml of 1% hemicellulase “Amano” aqueous solution were added, and the enzyme treatment was carried out in the same manner. Sheet preparation and paper strength measurement.

(Comparative Example 6)
In Comparative Example 3, instead of 16 ml of 1% cellulase A “Amano” aqueous solution, 8 ml of 1% cellulase A “Amano” aqueous solution, 8 ml of 1% hemicellulase “Amano” aqueous solution and 8 ml of 1% lipase A “Amano” aqueous solution were added. In the same manner, the enzyme treatment was performed, and hand-sheets were prepared and the paper strength was measured.

  It can be seen that the fibrillation of the pulp has progressed by comparing the freeness of Examples 1 to 14 in Table 1 with Comparative Examples 1 and 2 and adding the enzyme composition before beating. It can be seen that the filtrate turbidity of Examples 1 to 14 is 500 ppm or less as compared with the filtrate turbidity of Comparative Examples 1 to 6, and the yield and fixing of papermaking sludge are improved. In addition, the specific burst strength of the handmade sheets of Examples 1 to 14 is 8.1% to 20.9% higher than the specific burst strength of the handmade sheets of Comparative Examples 1 to 6. Even after the enzyme treatment with cellulase and / or hemicellulase, or the enzyme treatment using cellulase and / or hemicellulase and esterase in combination, the beating treatment is performed to improve the yield of papermaking sludge and blend papermaking sludge. It can be seen that not only the burst strength is maintained, but also an improvement in strength is obtained.

The present invention is useful for promoting the reuse of papermaking sludge generated in the papermaking process and wastewater sludge generated in the wastewater treatment process as raw materials for papermaking.

Claims (5)

A method of manufacturing paper or paperboard,
(A) Paper sludge is blended and mixed with pulp slurry, (b) an enzyme composition containing a cellulolytic enzyme is added, (c) beating treatment is performed, and (d) paper or paperboard is produced. Paper or paperboard manufacturing method. The method for producing paper or paperboard according to claim 1, wherein the cellulolytic enzyme is cellulase and / or hemicellulase. The method for producing paper or paperboard according to claim 1 or 2, wherein the hemicellulase is xylanase. The method for producing paper or paperboard according to claim 1, wherein the enzyme composition comprises cellulase, hemicellulase, and esterase. The method for producing paper or paperboard according to claim 1, wherein the enzyme composition comprises a separated culture of Chrysosporium racunowens garg 27K (deposit number VKMF-3500D).