JP2000043408A - Inkjet recording sheet - Google Patents

Abstract

An object of the present invention is to obtain an ink jet recording sheet having high ink absorption and high gloss. An ink-receiving layer and a gloss-generating layer are sequentially laminated on a support, and the ink-receiving layer is formed by applying an organic polymer fine particle having a glass transition temperature of 50 ° C. or higher and a pigment as essential components and coating the gloss-generating layer. By performing the calendering process, an intended ink jet recording sheet is obtained. Further, an ink jet recording sheet having a higher gloss can be obtained by applying a glossy layer after calendering the ink receiving layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording sheet having excellent ink absorptivity and gloss such as commercially available coated paper and art paper.

[0002]

2. Description of the Related Art In an ink jet recording system, fine droplets of ink are caused to fly according to various operating principles and adhere to a recording sheet such as paper, thereby recording images and characters. The recording method has features such as high speed, low noise, easy multi-coloring, great flexibility in recording patterns, and no need for development and fixing. It is rapidly spreading in applications.
Further, the image formed by the multi-color ink jet method can obtain a record comparable to multi-color printing by the plate making method and printing by the color photographic method by expanding the resolution and the color reproduction range, In applications where the number of copies required is small, it is being widely applied to the field of full-color image recording because it is cheaper than by photographic technology.

The recording sheet used in this ink jet recording system has a high density of print dots, a bright and vivid color tone, and a high ink absorption, so that even when the print dots overlap, the ink flows or bleeds. It is required that the print dots do not smear, that the diffusion of print dots in the horizontal direction is not unnecessarily large, and that the periphery is smooth and not blurred.

As an ink jet recording sheet having high gloss, for example, JP-A-61-197285 discloses a method in which a porous ink receiving layer is formed on a transparent support, and an image formed on the ink receiving layer is formed. A method of observing from the support side has been proposed. JP-A-3-215081 discloses a method in which a dye-adsorbing layer composed of porous alumina hydrate and a solvent-absorbing layer composed of porous silica are sequentially laminated on a transparent support to support an image formed on the dye-adsorbing layer. A method of observing from the body side has been proposed. However, in these methods, when printing an image, it is necessary to perform image processing so as to be a mirror image, and furthermore, the support to be used is limited to those having transparency.

[0005] JP-A-2-113986 discloses a method of casting after treatment with an aqueous solution containing a cationic polymer electrolyte, and JP-A-2-274587 discloses a method of using colloidal silica to improve gloss and using a cationic polymer. A method of casting after treatment with an aqueous solution containing a polymer electrolyte has been proposed. However, the use of a cationic polymer electrolyte causes the surface of the printed portion to be roughened because the cationic polymer electrolyte present on the surface is re-dissolved in the ink when printing, and the gloss of the printed portion and the image The sharpness tends to decrease.

Japanese Patent Application Laid-Open No. 7-101142 discloses that
A method of calendering by applying a glossy layer composed of colloid particles and a synthetic polymer latex on the ink receiving layer has been proposed. However, even in this method, a high-pressure calendar Processing is required, which causes a decrease in ink absorbency. For this reason, in the calendar process, it is necessary to select conditions within the range of the allowable ink absorption capacity, and it is difficult at present to cope with both ink absorption and gloss with the current technology.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet recording sheet having high gloss, which ensures ink absorption which affects image quality in ink jet recording.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above problems, an ink jet recording sheet that can solve the problems of the present invention has been found.

That is, the ink jet recording sheet of the present invention has an ink receiving layer and a gloss developing layer sequentially laminated on a support, and the ink receiving layer comprises organic polymer fine particles having a glass transition temperature of 50 ° C. or higher and a pigment as essential components. Wherein the glossy layer is calendered.

It is preferable that the organic polymer fine particles have a solid content weight ratio of 50/100 to 10/100 with respect to the pigment, since ink absorbency and gloss increase.

It is preferable that the pigment is mainly a synthetic amorphous silica since the ink absorbency and the color developing property are enhanced.

Furthermore, when the ink receiving layer is calendered and then a gloss developing layer is applied, more excellent gloss can be obtained.

Further, by performing the calendering treatment with a soft calender comprising a metal roll and a synthetic resin roll, excellent gloss and excellent ink absorption can be obtained.

When the 75 ° specular glossiness specified in JIS Z8741 is 40% or more, the ink jet recording sheet of the present invention has gloss comparable to commercially available coated paper and art paper.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the ink jet recording sheet of the present invention will be described in detail.

According to the present invention, an ink receiving layer and a gloss developing layer are sequentially laminated on a support, and the ink receiving layer comprises organic polymer fine particles having a specific glass transition temperature or higher and a pigment as essential components. By calendering the expression layer, an ink jet recording sheet having excellent ink absorbency and gloss is obtained.

The support used in the present invention includes LB
Chemical pulp such as KP, NBKP, GP, PGW, RM
Wood pulp and kenaf such as mechanical pulp such as P, TMP, CTMP, CMP and CGP, waste paper pulp such as DIP,
Bagasse, bamboo, non-wood pulp such as cotton and conventionally known pigment as the main components, binder and sizing agent and fixing agent,
A base paper manufactured by various apparatuses such as a fourdrinier paper machine, a circular net paper machine, a twin wire paper machine, by mixing with one or more kinds of various additives such as a retention aid, a cationizing agent, and a paper strength enhancer. Further, the base paper includes base paper provided with a size press using starch, polyvinyl alcohol or the like or an anchor coat layer, and coated paper such as art paper, coated paper, cast coated paper provided with a coat layer thereon. Such a base paper and a coated paper may be provided with a coating layer according to the present invention as they are, or a machine calendar, T
A calendar device such as a G calendar or a soft calendar may be used. The basis weight of the support is usually 4
It is 0 to 300 g / m ² , but is not particularly limited.

As the support, a polyolefin resin layer may be provided on the above-described base paper, or a film material of a synthetic resin such as polyethylene, polypropylene, polyester, nylon, rayon, polyurethane, or a mixture thereof, It is also applicable to a sheet formed by forming a synthetic resin into fibers.

The ink receiving layer according to the present invention comprises organic polymer fine particles having a glass transition temperature of 50 ° C. or higher and a pigment as essential components, and a binder, an additive and the like.

The organic polymer fine particles referred to in the present invention include:
For example, conjugated diene copolymers such as styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, acrylic polymers such as acrylate and methacrylate polymers or copolymers, and ethylene vinyl acetate copolymer A vinyl polymer such as a polymer, or a polymer modified with a functional group-containing monomer such as a carboxyl group of these various polymers is used. The glass transition temperature of the organic polymer fine particles must be 50 ° C. or higher. If the glass transition temperature is lower than 50 ° C., the organic polymer fine particles are thermally melted by drying at the time of coating the ink receiving layer to form a film on the pigment surface. As a result, the ink absorbency decreases. When the glass transition temperature is 50 ° C. or higher, only partial thermal melting occurs, and the degree of coating on the pigment surface is small. Further, when the glass transition temperature is 80 ° C. or higher, thermal melting hardly occurs, which is more desirable. The particle size and shape of the organic polymer particles are
Although not particularly limited, a commercially available spherical particle having a particle size of several tens to several hundreds of nm is applied.

As the pigment used in the ink receiving layer,
One or more known white pigments can be used. For example, light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth,
White inorganic pigments such as calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, pseudoboehmite, aluminum hydroxide, lithopone, zeolite, hydrohaloysite, magnesium hydroxide, styrene plastic pigment, and acrylic Organic pigments such as plastic pigment, polyethylene, microcapsules, urea resin, and melamine resin. From the viewpoint of ink absorption, a porous pigment is preferable, and in particular, synthetic amorphous silica, which is also excellent in color development, is preferable.

The binder used in the ink receiving layer includes starch derivatives such as oxidized starch, etherified starch and phosphated starch, carboxymethylcellulose, and the like.
Water-soluble polymers such as cellulose derivatives such as hydroxyethylcellulose, casein, gelatin, soybean protein, polyvinyl alcohol or derivatives thereof are mainly used. In addition to the above, conjugated diene copolymer latex such as styrene-butadiene copolymer and methyl methacrylate-butadiene copolymer having a glass transition temperature of less than 50 ° C., and polymers of acrylates and methacrylates Or an acrylic polymer latex such as a copolymer, a vinyl polymer latex such as an ethylene-vinyl acetate copolymer, or a functional group-modified polymer latex of a functional group-containing monomer such as a carboxyl group of these polymers. Aqueous adhesives such as thermosetting synthetic resins such as melamine resin and urea resin, acrylic acid ester such as polymethyl methacrylate, polymer or copolymer resin of methacrylic acid ester, polyurethane resin, unsaturated polyester resin, vinyl chloride For vinyl acetate copolymer, polyvinyl butyral, alkyd resin, etc. Resin adhesives may also be used. When using these latexes as binders, it is usually desirable that the glass transition temperature is lower,
Those having a glass transition temperature of 50 ° C. or higher are not used because the effect as a binder is low. The amount of the binder is 3 to 70 parts by weight, based on 100 parts by weight of the pigment.
Preferably, it is 5 to 50 parts by weight, and if it is less than 3 parts by weight, the coating layer strength of the ink receiving layer is insufficient, and if it exceeds 70 parts by weight, the ink absorbency decreases.

Further, organic polymer fine particles having a glass transition temperature of 50 ° C. or higher have a solids content ratio of 50/100
-10/100 is desirable. If it exceeds 50/100, the ink absorbency may decrease, and if it is less than 10/100, it may be difficult to obtain strong gloss.

In the ink receiving layer, additives such as a dye fixing agent, a pigment dispersant, a thickener, a fluidity improver, an antifoaming agent, a foam inhibitor, a release agent, a foaming agent, a penetrant, a coloring dye , Coloring pigments,
A fluorescent whitening agent, an ultraviolet absorber, an antioxidant, an antiseptic, an antibacterial agent, a waterproofing agent, a wet paper strength enhancer, a dry paper strength enhancer, and the like can also be appropriately compounded.

The coating amount of the ink receiving layer varies depending on the required gloss, ink absorbency, type of the support and the like, but is usually 1 g / m ² or more. In addition, the ink receiving layer can be coated with a certain coating amount divided into two times,
Gloss is improved as compared with applying the coating amount at one time.

Examples of the coating device for the ink receiving layer include various blade coaters, roll coaters, air knife coaters, bar coaters, rod blade coaters, curtain coaters, short dwell coaters, size presses, and the like. Can be applied off-machine.

The ink receiving layer does not need to be calendered, but it is desirable to calender the ink receiving layer in order to obtain a particularly high gloss. Examples of the calendar device include a machine calendar, a TG calendar, a super calendar, and a soft calendar. Among them, a soft calendering treatment in which the absorption capacity of the ink receiving layer is small is more desirable.

The soft calender described in the present invention is:
It has at least one or more sets of metal rolls and synthetic resin rolls.

As the metal roll used in the soft calender, a carbon steel material is often used, but the material is not particularly limited. Further, the roll surface may be protected by spraying ceramic, chromium, or the like. As for the surface temperature of the metal roll, high-temperature treatment is more preferable because occurrence of density unevenness can be reduced. The surface temperature of the metal roll varies depending on the calendering speed and the linear pressure.
0 ° C. is a suitable temperature.

As the material of the synthetic resin roll, a urethane-based, ebonite-based, nylon-based, or aramid-based synthetic resin is used, and the hardness is JIS Z2246.
HsD 70 to 95 with a specified Shore hardness is used. The synthetic resin roll has a central portion made of an iron core and a surface layer made of a synthetic resin layer made of the above-described material. However, the synthetic resin layer may have a multilayer structure.

The gloss developing layer according to the present invention comprises a coating composition containing colloid particles and a binder as main components. The colloid particles according to the present invention are those that are suspended and dispersed in water to form colloids, and mean inorganic particles or organic polymer particles having an average particle diameter of 300 nm or less measured by a dynamic scattering method. . For example, alumina sol such as colloidal silica, boehmite and pseudo-boehmite, colloidal alumina, cationic aluminum oxide or a hydrate thereof, or colloidal silica particles as disclosed in Japanese Patent Publication No. Inorganic particles such as coated particles, polystyrene, methyl methacrylate, styrene-butadiene copolymer,
Conjugated diene-based copolymers such as methyl methacrylate-butadiene copolymer, polymers or copolymers of acrylates and methacrylates, microcapsules, urea resins, organic polymer fine particles such as melamine, and the like. It is also possible to use two or more kinds in combination.

In the glossy layer of the present invention, one or more known white pigments can be used in combination with the colloid particles. Since the white pigment generally has a large particle diameter and causes opacity, the weight ratio of the colloid particles / the white pigment is preferably 80/20 or more, more preferably 90/10 or more, depending on the particle diameter of the white pigment. It is.

Further, as the binder used in the glossy layer, starch derivatives such as oxidized starch, etherified starch, and phosphated starch, carboxymethyl cellulose,
Cellulose derivatives such as hydroxyethylcellulose, casein, gelatin, soybean protein, polyvinyl alcohol or derivatives thereof, polyvinylpyrrolidone, maleic anhydride resin, conjugated diene copolymers such as styrene-butadiene copolymer and methyl methacrylate-butadiene copolymer Latex, acrylic polymer latex such as acrylic polymer such as polymer or copolymer of acrylic acid ester and methacrylic acid ester, vinyl polymer latex such as ethylene vinyl acetate copolymer, or these various polymers Of functional group-modified polymer latex with a functional group-containing monomer such as a carboxyl group, an aqueous adhesive such as a thermosetting synthetic resin such as a melamine resin or a urea resin, an acrylic ester such as polymethyl methacrylate, or a methacrylic ester. Coalescence or copolymer Fat, polyurethane resins, unsaturated polyester resins, vinyl chloride - can be exemplified vinyl acetate copolymer, polyvinyl butyral, alkyd synthetic resin adhesive such as a resin or the like.

The blending amount of the binder is 5 to 70 parts by weight, preferably 5 to 50 parts by weight, based on 100 parts by weight of the pigment. If the amount exceeds 70 parts by weight, the ink absorbency decreases.

Further, in the gloss developing layer, additives such as a dye fixing agent, a pigment dispersant, a thickener, a flow improver, an antifoaming agent, a foam inhibitor, a release agent, a foaming agent, a penetrant, A coloring dye, a coloring pigment, a fluorescent whitening agent, an ultraviolet absorber, an antioxidant, a preservative, an antibacterial agent, a waterproofing agent, a wet paper strength enhancer, a dry paper strength enhancer, and the like can also be appropriately compounded.

Examples of the coating device for the gloss-developing layer include various blade coaters, roll coaters, air knife coaters, bar coaters, rod blade coaters, curtain coaters, short dwell coaters, size presses and the like. As the coating amount of the glossy layer,
Although it depends on the smoothness and size of the ink receiving layer and the required gloss, it may be 2 g / m ² or more. Further, after the glossy layer is applied, it is also possible to correct the curl by spraying humidified air or humidified steam on the back surface of the glossy layer sandwiching the support.

As a method for imparting gloss after the application of the gloss developing layer, a calendar device such as a machine calendar, a super calendar, a TG calendar, or a soft calendar is used.

Further, the ink jet recording sheet of the present invention may be provided not only in a cut sheet but also in a roll form. Further, the present invention is not limited to use as an ink jet recording sheet, and may be used as any recording sheet using a liquid ink at the time of recording. For example,
A heat-meltable substance, a hot-melt ink containing a dye or pigment as a main component, is coated on a thin support such as a resin film, a high-density paper, or a synthetic paper. An image receiving sheet for thermal transfer recording, which melts and transfers ink, an ink jet recording sheet, which heats and melts the heat fusible ink to form fine droplets, and performs flight recording, an ink jet recording sheet using an ink in which an oil-soluble dye is dissolved in a solvent, An image-receiving sheet corresponding to a photosensitive pressure-sensitive donor sheet using a microcapsule containing a polymerizable monomer and a colorless or colored dye / pigment is exemplified.

The common feature of these recording sheets is that the ink is in a liquid state at the time of recording. The liquid ink penetrates in the depth direction or the horizontal direction of the ink receiving layer of the recording sheet until it hardens, solidifies or fixes. The above-described various recording sheets require absorptivity according to each system, and the inkjet recording sheet of the present invention may be used as the above-described various recording sheets. Further, the ink jet recording sheet of the present invention may be used as a recording sheet for heating and fixing an electrophotographic recording toner widely used in copiers, printers, etc. It is also possible to use it.

[0040]

The present invention will be described below with reference to examples of the present invention.
The present invention is not limited to these examples. Further, "parts" and "%" shown in Examples are parts by weight and% by weight unless otherwise specified.

In the following Examples and Comparative Examples, the support and the organic polymer fine particles were prepared as follows.

<Preparation of Support> The support was composed of 80 parts of LBKP (freeness 400 mlcsf) and NBKP (freeness 450).
mlcsf) 10 parts of pigment having a ratio of light calcium carbonate / heavy calcium carbonate / talc to 10/10 parts per 100 parts of wood pulp consisting of 20 parts, 20 parts of commercially available alkyl ketene dimer, 0.10 parts of commercially available cationic (Meta)
0.03 parts of acrylamide, commercially available cationized starch 0.
After preparing 80 parts and 0.40 parts of a sulfuric acid band, papermaking was performed using a Fourdrinier paper machine with a basis weight of 90 g / m ² .

<Preparation of Organic Polymer Fine Particles> Organic polymer fine particles were prepared by using methyl methacrylate, methyl acrylate, and ethyl acrylate as monomers, varying the ratio thereof, and using a polymerization initiator and a surfactant. These monomers were copolymerized to obtain organic polymer fine particles A to E.
From the result of observation with an electron microscope, the particle diameter of these organic polymer fine particles was 70 nm, and the shape was spherical. The glass transition temperature was determined from a DTA curve based on JIS K7121. The glass transition temperature of the organic polymer fine particles A is 86
° C. The glass transition temperature of the organic polymer fine particles B is
57 ° C. The glass transition temperature of the organic polymer fine particles C was 27 ° C. The glass transition temperature of the organic polymer fine particles D was 13 ° C. The glass transition temperature of the organic polymer fine particles E was −10 ° C.

Example 1 <Coating of Ink Receiving Layer> The coating composition of the ink receiving layer was as follows:
A liquid was prepared by using 50 parts of organic polymer fine particles A, 100 parts of synthetic amorphous silica (Fine Seal X37B: manufactured by Tokuyama Soda Co., Ltd.), and 30 parts of polyvinyl alcohol (PVA117: manufactured by Kuraray Co., Ltd.) at a solid concentration of 18%. The coating solution was applied and dried on the support by an air knife coater so that the absolute dry coating amount was 10 g / m ² .

<Coating of Gloss Expression Layer> The coating composition of the gloss expression layer was composed of 100 parts of colloidal silica (Snowtex AK: manufactured by Nissan Chemical Industries, Ltd.) and polyvinyl alcohol (PVA1).
17: Kuraray Co., Ltd.) and a cationic dye fixing agent (Sumireze Resin 1001: Sumitomo Chemical Co., Ltd.) 10 parts were prepared at a solid concentration of 16%. This coating liquid was provided on the ink receiving layer by an air knife coater so as to have a coating amount of 8 g / m ^2, and was subjected to a super calender treatment at a linear pressure of 100 kg / cm to obtain an ink jet recording sheet of Example 1.

Example 2 The ink receiving layer was prepared by adding the organic polymer fine particles A of Example 1 to 10
It was obtained in the same manner except that 0 parts were used. The ink jet recording sheet of Example 2 was obtained in the same manner as in Example 1 for the glossy layer.

Example 3 The ink receiving layer was prepared by adding the organic polymer fine particles A of Example 1 to 10
The same procedure was performed except that the parts were used. The ink jet recording sheet of Example 3 was obtained in the same manner as in Example 1 for the glossy layer.

Example 4 An ink receiving layer was obtained in the same manner as in Example 1 except that the amount of the organic polymer fine particles A was changed to 5 parts. The gloss developing layer was prepared in Example 1.
In the same manner as in the above, an ink jet recording sheet of Example 4 was obtained.

Example 5 The ink receiving layer was obtained in the same manner as in the coating composition of Example 1, except that the organic polymer fine particles A were replaced with the organic polymer fine particles B. The inkjet recording sheet of Example 5 was obtained in the same manner as in Example 1 for the glossy layer.

Example 6 The ink receiving layer was prepared by adding the organic polymer fine particles B of Example 5 to 10
The same procedure was performed except that the parts were used. The ink jet recording sheet of Example 6 was obtained in the same manner as in Example 1 for the glossy layer.

Example 7 An ink receiving layer was obtained in the same manner as in Example 1, and then subjected to a linear pressure of 1
A machine calender treatment was performed using a combination of a metal roll of 00 kg / cm and a metal roll. The gloss developing layer was prepared in Example 1.
In the same manner as in the above, an ink jet recording sheet of Example 7 was obtained.

Example 8 An ink receiving layer was obtained in the same manner as in Example 1, and then subjected to a linear pressure of 1
A super calender treatment was performed using a combination of a 00 kg / cm metal roll and a cotton roll. The inkjet recording sheet of Example 8 was obtained in the same manner as in Example 1 for the glossy layer.

Example 9 An ink receiving layer was obtained in the same manner as in Example 1, and then subjected to a linear pressure of 1
A soft calender treatment was performed using a combination of a 00 kg / cm metal roll and a synthetic resin roll. As the glossy layer, an ink jet recording sheet of Example 9 was obtained in the same manner as in Example 1.

Example 10 The ink receiving layer was the same as Example 1 except that the synthetic amorphous silica in the coating composition of Example 1 was replaced with light calcium carbonate (Tamapearl 121: manufactured by Okutama Kogyo KK). I got it. Example 10 was carried out in the same manner as in Example 1 except that the gloss developing layer was used.
Was obtained.

Comparative Example 1 The ink-receiving layer was prepared by mixing the coating composition of Example 1 with an organic polymer fine particle at a solid content of 16% without blending the organic polymer fine particles, and coating and drying under the same conditions as in Example 1. did. The gloss developing layer was prepared in Example 1.
In the same manner as in the above, an ink jet recording sheet of Comparative Example 1 was obtained.

Comparative Example 2 An ink receiving layer was obtained in the same manner as in Comparative Example 1 and then subjected to a linear pressure of 100
A super calendar treatment of kg / cm was performed. As for the gloss developing layer, an ink jet recording sheet of Comparative Example 2 was obtained in the same manner as in Example 1.

Comparative Example 3 An ink receiving layer was obtained in the same manner as in Comparative Example 1. The glossy layer was obtained in the same manner as in Example 1 except that the super calender treatment was performed at a linear pressure of 200 kg / cm to obtain an inkjet recording sheet of Comparative Example 3.

Comparative Example 4 An ink receiving layer was obtained in the same manner as in Example 1. As for the gloss developing layer, an ink jet recording sheet of Comparative Example 4 was obtained in the same manner as in Example 1 except that the supercalender treatment was not performed.

Comparative Example 5 An ink receiving layer was obtained in the same manner as in Example 7. The glossy layer was obtained in the same manner as in Example 1, except that the super calender treatment was omitted, to obtain an ink jet recording sheet of Example 7.

Comparative Example 6 An ink receiving layer was obtained in the same manner as in Example 1 except that the synthetic amorphous silica was removed. As the glossy layer, an ink jet recording sheet of Comparative Example 6 was obtained in the same manner as in Example 1.

Comparative Example 7 An ink-receiving layer was obtained in the same manner as in the coating composition of Example 1, except that the organic polymer fine particles A were replaced with the organic polymer fine particles C. The ink jet recording sheet of Comparative Example 7 was obtained in the same manner as in Example 1 for the glossy layer.

Comparative Example 8 An ink receiving layer was obtained in the same manner as in the coating composition of Example 1, except that the organic polymer fine particles A were replaced with the organic polymer fine particles D. The inkjet recording sheet of Comparative Example 8 was obtained in the same manner as in Example 1 for the glossy layer.

Comparative Example 9 An ink receiving layer was obtained in the same manner as in the coating composition of Example 1, except that the organic polymer fine particles A were replaced with the organic polymer fine particles E. The inkjet recording sheet of Comparative Example 9 was obtained in the same manner as in Example 1 for the glossy layer.

The ink jet recording sheets produced in each of the examples and comparative examples were evaluated by the following evaluation methods. The measurement and the evaluation were performed under the environment specified in JIS P8111.

<Specular glossiness> Glossiness is measured in accordance with JIS Z87.
According to No. 41, the angle of incidence and reflection was measured at 75 degrees by a variable angle glossmeter (VGS-1001DP) manufactured by Nippon Denshoku Industries Co., Ltd. The gloss is comparable to a commercial coated paper with a gloss of 40% or more and a commercial art paper with a gloss of 60% or more.

<Ink Absorbency> Using an ink jet recording apparatus (BJC420J: manufactured by Canon Inc.), a grid pattern of white lines (non-printed portion) was created in a mixed color solid pattern composed of cyan ink and magenta ink, and The bleeding of the ink was visually evaluated according to the following criteria. ◎: The lattice is completely clear. ：: Bleeding of ink is seen in only a part of the grid. Δ: The grid becomes narrow, and ink seepage is generally observed. ×: Lattice is missing due to bleeding of ink. The level at which there is no practical problem is △ or more.

[0067]

[Table 1]

As is clear from Table 1, by using organic polymer fine particles having a glass transition temperature of 50 ° C. or higher for the ink receiving layer, gloss was improved and ink absorption was ensured. The use of synthetic amorphous silica as the pigment in the ink receiving layer further improved the ink absorbency. Further, when organic polymer fine particles having a glass transition temperature of 50 ° C. or higher were added to the ink receiving layer, gloss was improved by plasticization by calendering treatment, and an ink jet recording sheet having high absorbency and excellent gloss was obtained. In addition, the organic polymer fine particles in the ink receiving layer have a solid content weight ratio of 5 to the pigment.
At 0/100 to 10/100, high gloss and excellent ink absorption were obtained. Further, by calendering the ink receiving layer, the gloss was further improved. Among the calendering treatments, particularly in the soft calendering treatment, excellent glossiness and excellent ink absorbency were obtained. In the ink receiving layer to which the organic polymer fine particles were not added, calendering at a high linear pressure was necessary in order to obtain the same level of gloss, resulting in a decrease in ink absorbency. In the case of organic polymer fine particles having a glass transition temperature of less than 50 ° C., the ink receiving layer is melted during drying and coats the pigment surface.
The ink absorbency decreased.

[0069]

According to the present invention, an ink receiving layer and a gloss developing layer are sequentially laminated on a support, and the ink receiving layer contains organic polymer fine particles having a glass transition temperature of 50 ° C. or higher and a pigment as essential components. It is composed of a coating composition, and by calendering the glossy layer, the glossiness can be improved while maintaining the ink absorbability, and the color inkjet recording is fine, glossy, and high-quality inkjet recording. We can provide sheets.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) D21H 27/00 D21H 1/28 Z 5/00 Z F-term (Reference) 2C056 FC06 2H086 BA16 BA32 BA33 BA34 BA41 4D075 BB05Y CA35 CB04 DA03 DB18 DC27 EB53 EB56 EC03 EC11 EC54 4L055 AG12 AG18 AG64 AG71 AG94 AG96 AH02 AH37 AJ04 BE02 BE09 EA11 EA20 EA32 FA12 FA15 GA09

Claims (6)

[Claims] 1. An ink jet recording sheet comprising an ink receiving layer and a gloss developing layer sequentially laminated on a support, wherein the ink receiving layer comprises organic polymer fine particles having a glass transition temperature of 50 ° C. or higher and a pigment as essential components. An ink jet recording sheet comprising a coating composition, wherein the glossy layer is calendered. 2. The ink jet recording sheet according to claim 1, wherein the solid content weight ratio of the organic polymer fine particles to the pigment is 50/100 to 10/100. 3. The ink jet recording sheet according to claim 1, wherein the pigment is mainly synthetic amorphous silica. 4. The method according to claim 1, wherein the gloss receiving layer is laminated after the calendering of the ink receiving layer.
3. The ink jet recording sheet according to 3. 5. The ink jet recording sheet according to claim 4, wherein the calendering of the ink receiving layer is performed by a soft calendering process comprising a metal roll and a synthetic resin roll. 6. The ink jet recording sheet according to claim 1, wherein a 75-degree specular glossiness specified in JIS Z8741 is 40% or more.