JP2003266925A - Ink jet recording sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of a surface strength that the conventional ink jet recording medium indicates a low strength of an ink receiving layer and consequently, a pigment comes off or an ink receiving layer peels off due to the rubbing of the surface and the like, although an improvement of a record quality level of a character, an image or the like is ever proposed. <P>SOLUTION: This invention relates to the recording medium with said problem solved in such a way that an easy adhesion-treated layer containing a pigment and a resin and the ink receiving layer are sequentially laminated on at least one side of a base material and the resin of the easy adhesion-treated layer and the ink receiving layer are more than one kind selected from among a polyvinyl alcohol with a degree of polymerization of 1,500 or more or a degree of saponification of 90 mol% or more, a styrene-butadiene copolymer, an acrylic ester copolymer and a polyurethane resin. Further, the pigment content of the ink receiving layer is larger than that of the easy adhesion-treated layer. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording sheet material used in various ink jet recording type devices, and in particular, it has good color developability, surface strength, adhesiveness to a substrate and an ink receiving layer, The present invention relates to an ink jet recording sheet which is hard to be peeled off from a recorded image, has good water resistance and scratch resistance, and can also be used for commercial wide format output.

[0002]

2. Description of the Related Art Ink jet printers have characteristics such as sharpness of recording, quietness of sound, and ease of colorization. Nowadays, even in business applications, it has a large size due to the high precision of the mechanism, high coloring, high-definition image output and printing ink equivalent to dye ink by improving the performance of water-based pigment, oil-based pigment ink and its print head. Image output with comparable image storability is now possible. In addition, reduction of introduction cost, 1
Since it is possible to print small lots from a single sheet and output a wide variety of images using digital images, it is rapidly spreading to applications such as printing, signboards, advertisements, posters, bus wrapping, and wallpaper for interior and exterior of events. .

In recent years, the introduction of ink jet printers for the above-mentioned business uses has rapidly increased, and in addition to the conventional print quality, recording sheets are required to have ink jet recording suitability for various materials and image durability. It has become. For example, paper, cloth, synthetic paper, non-woven fabric, olefin film such as PE / PP, vinyl chloride film and the like are used as materials, and water resistance and scratch resistance are required as durability. Also, it is now an essential condition for inkjet recording sheets to secure recording quality such as high print density and ink absorbency, and to secure durability of recording sheets and output images together with imparting recording aptitude to various kinds of materials. It is the current situation.

[0004]

However, in the conventional ink jet recording sheet, although proposals for improving the recording quality of characters, images, etc. have been made, they are still insufficient. In addition, the ink jet recording sheet has a resolution,
An ink-receiving layer containing a large amount of pigment component that excels in ink absorption is formed in order to obtain clearness, but if the amount of the pigment component is increased to improve recording quality, the strength of the ink-receiving layer itself and the substrate , The interlayer strength with the surface layer is reduced. Also,
As a result, powder fall off in the processing process, paper feeding failure in the printer, and the amount of ink used during full-color recording increases, the strength of the ink receiving layer decreases, and the surface is rubbed. There is a problem with respect to the surface strength such that the pigment falls off and the ink receiving layer peels off.

Therefore, the present invention has been made in view of the above-mentioned circumstances in the prior art, and has good ink jet recording characteristics, and also has a surface such as adhesion to a substrate, scratch resistance and water resistance. An inkjet recording sheet having excellent strength is provided.

[0006]

Means for Solving the Problems The present invention has been made as a result of intensive studies for solving the above-mentioned problems, and includes polyvinyl alcohol having a specific saponification degree and a polymerization degree, a styrene-butadiene copolymer, and acrylic acid. Ester copolymer, one or more selected from a polyurethane resin, by blending the easy-adhesion treatment layer and the ink receiving layer, while having good recording properties such as ink absorption and color development,
The inventors have found that the surface strength such as adhesion to a substrate is effectively improved, and have completed the present invention.

That is, in the invention of claim 1 of the present invention, an easy-adhesion treatment layer containing a pigment and a resin and an ink receiving layer are sequentially laminated on at least one surface of a substrate, and the easy-adhesion layer is provided. The resin of the treatment layer and the ink receiving layer is a polyvinyl alcohol having a polymerization degree of 1500 or more or a saponification degree of 90 mol% or more, a styrene-butadiene copolymer, an acrylic ester copolymer,
It is one or more selected from polyurethane resins, and the ink receiving layer is characterized in that the content of the pigment is larger in the ink receiving layer than in the easily adhesive treatment layer.

The invention of claim 2 is the ink jet recording sheet according to claim 1, characterized in that the content of polyvinyl alcohol in the easy adhesion treatment layer is 1 to 30% by weight. In the invention of Item 3, the content of polyvinyl alcohol in the ink receiving layer is 5 to 5
The inkjet recording sheet according to claim 1 or 2, wherein the content is 0% by weight.

The invention according to claim 4 is characterized in that the content of the pigment in the easy-adhesion-treated layer is 5 to 50% by weight, and the inkjet according to claim 1, 2 or 3. A recording sheet, wherein the ink receiving layer has a pigment content of 40 to 9
The inkjet recording sheet according to any one of claims 1, 2, 3 and 4, wherein the content is 5% by weight.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The ink jet recording sheet of the present invention comprises a base material and an easily adhesive treatment layer and an ink receiving layer which are sequentially laminated on at least one surface of the base material. In the present invention, if necessary, a glossiness adjusting layer as formed by a conventional inkjet recording paper may be provided on the surface of the ink receiving layer, or a back coat layer may be provided on the back surface of the substrate. You may. Next, each layer structure of the present invention will be described.

(1) Substrate The substrate on which the easy adhesion treatment layer used in the present invention is applied is
Chemical pulp such as LBKP and NBKP, GP, PGW,
Main components are mechanical pulp such as RMP, TMP, CTMP, CMP, CGP, and wood pulp such as waste paper pulp such as DIP, and pigments, binders and sizing agents, fixing agents, yield improving agents, cationizing agents, paper strengthening agents. A mixture of at least one type of various additives such as, etc., and a raw paper produced by various devices such as a Fourdrinier paper machine, a cylinder paper machine, a twin wire paper machine, and the size of the raw paper using starch and polyvinyl alcohol. Also included are base papers provided with an anchor coat layer by a press or a gate roll coater, and coated papers such as art papers, coated papers and cast coated papers provided with a coat layer thereon. The base paper and the coated paper may be provided with the ink receiving layer as they are, or for the purpose of controlling flatness,
A calendar device such as a machine calendar, a TG calendar or a soft calendar may be used.

As the base material, a polyolefin resin layer may be provided on the above-mentioned base paper by a laminating method,
It is possible to use a synthetic resin such as polyethylene, polypropylene, polyester, nylon, rayon, polyurethane, a film of a mixture thereof, or a fiber formed by molding these synthetic resins. In addition, in the ink jet recording using a conventional water-based ink, these base materials have a problem that the adhesiveness of the ink receiving layer formed on the surface is extremely inferior to that of the above paper. It was a thing. However, by providing the laminated structure of the present invention, excellent adhesion to these substrates is achieved.

(2) Easy-Adhesion Treatment Layer (a) Pigment The easy-adhesion treatment layer in the present invention comprises at least a pigment and a resin, and as such a pigment, one or more kinds of various inorganic and organic pigments are used. be able to. For example, light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous Quality silica, colloidal silica,
Colloidal alumina, pseudo-boehmite, aluminum hydroxide, alumina, lithopone, zeolite, hydrohalloysite, magnesium carbonate, inorganic pigments such as magnesium hydroxide, styrene resin, acrylic resin, polyethylene,
Examples thereof include organic pigments which are resin particles such as urea resin and melamine resin.

Among the above, as the white pigment contained as a main component, a porous inorganic pigment is preferable because of its excellent drying property and absorption property of the ink-jet ink, and porous synthetic amorphous silica and porous carbonic acid are preferable. Examples thereof include magnesium and porous alumina. Among them, in the present invention, both the recording property and the storage stability (water resistance, abrasion resistance, light resistance, environmental gas resistance, indoor storage property, moisture resistance) are particularly excellent, and the specific surface area of 200 It is preferable to use sedimentary type and gel type porous amorphous silica of about 600 g / m ² . Further, when the ink receiving layer on the surface layer side is used as the gloss adjusting layer, it is most preferable to use colloidal silica or colloidal alumina as the pigment.

The easily adhesive treatment layer in the present invention preferably contains 5 to 50% by weight, especially 10 to 30% by weight of the above-mentioned pigment. If the content of the pigment is less than the above range, the ink absorbability may be impaired and the image may be blurred. On the contrary, if it is more than the above range, the surface strength may not be sufficiently obtained.

(B) Binder Resin In the present invention, the binder resin contained in the easily-adhesive-treated layer has a degree of polymerization of 150 from the viewpoint of water resistance and film strength.
It contains 0 or more or a polyvinyl alcohol having a saponification degree of 90 mol% or more, and one or more selected from a styrene-butadiene copolymer, an acrylic ester copolymer and a polyurethane resin.

The polyvinyl alcohol has a degree of polymerization of 1500 or more, preferably 2000 to 250.
A polyvinyl alcohol having a saponification degree of 0 or 0, or a saponification degree of 90 mol% or more, preferably 95 mol% or more is used, and a polyvinyl alcohol having a polymerization degree of 2000 or more and a saponification degree of 90 mol% or more is particularly preferable. It should be noted that modified polyvinyl alcohol such as carboxyl modified or sulfonic acid modified can also be used as long as it has such characteristics.

At least one resin selected from the styrene-butadiene copolymer, the acrylic ester copolymer, and the polyurethane resin used together with the above polyvinyl alcohol is not particularly limited, As a specific example, the following resins are used. The styrene-butadiene copolymer has a copolymerization ratio of styrene and butadiene of 2: 8 to 8: 2, preferably 5: 5.
It is 7: 3, and emulsion type is preferably used.

As the acrylic ester copolymer, a copolymer in which at least an alkyl ester of acrylic acid or methacrylic acid is used as a monomer component of the copolymer is appropriately used. Here, examples of the alkyl ester include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, and decyl, and lower alkyl esters having about 1 to 6 carbon atoms are preferable, and a hydroxyl group is further used. It may be an alkyl group having a substituent such as Further, two or more kinds of these (meth) acrylic acid alkyl esters may be contained as a monomer component. Other monomer components that form a copolymer with the (meth) acrylic acid alkyl ester are not particularly limited, and examples thereof include styrene, vinyl acetate, vinyl chloride, acrylic acid, methacrylic acid, acrylonitrile, and acrylamide. Various vinyl monomers such as

Further, as the polyurethane resin, various polyurethane resins such as ester-based, ether-based, ester / ether-based, carbonate-based, and isocyanate-based polyurethane resins can be appropriately used.

The easy-adhesion-treated layer in the present invention comprises at least one selected from the above-mentioned specific polyvinyl alcohol as a binder resin, the above-mentioned styrene-butadiene copolymer, acrylic ester copolymer and polyurethane resin. The styrene-butadiene copolymer is preferable because it is used in combination with the resin of (1), and the adhesiveness to the base material is particularly excellent. Further, the content of the specific polyvinyl alcohol is preferably 1 to 30% by weight, preferably 3 to 20% by weight, and particularly preferably 5 to 10% by weight, based on the total solid content of the easy adhesion treatment layer. If it is less than this range, the adhesiveness to the ink receiving layer is inferior and the surface strength such as easy peeling is not obtained, and if it is more than the range, the water resistance may be impaired.

Further, in addition to the above-mentioned resins, resins used as a binder resin in the conventional ink receiving layer, for example, vinyl acetate, oxidized starch, etherified starch, cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose, casein, Gelatin, soybean protein, silyl modified polyvinyl alcohol, etc .; maleic anhydride resin, conjugated diene copolymer latex of melamine-methyl methacrylate-butadiene copolymer; melamine resin,
Water-based adhesives such as thermosetting resins such as urea resins; synthetic resin adhesives such as polymethylmethacrylate, unsaturated polyester resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral and alkyd resins are used as necessary You can do it.

(3) Ink-Receptive Layer The ink-receptive layer contains a pigment used in the above-mentioned easy-adhesion treatment layer,
A binder resin can be used as appropriate. That is, the ink receiving layer in the present invention is composed of at least a pigment and a binder resin, and as the binder resin, the same specific polyvinyl alcohol, styrene-butadiene copolymer, and acrylic acid ester copolymer as the easy adhesion treatment layer are used. At least one resin selected from the grouped and polyurethane resins is used, but in the point that the ink receiving layer has more pigment content than the easy-adhesion treated layer, Is different. The content of the pigment is 40 relative to the total solid content of the ink receiving layer.
˜95 wt%, especially 50-70 wt%. If the content of the pigment is less than the above range, the ink absorbability may be impaired, and the image may bleed. On the contrary, if the content is more than the above range, the amount of the binder resin is too small, and the pigment may be missing. May result in insufficient surface strength.

The content of the specific polyvinyl alcohol in the ink receiving layer is 5 to 50% by weight, especially 10% by weight.
-30% by weight is preferred. If the amount is less than this range, the adhesiveness to the easily-adhesion-treated layer may be poor, and the surface strength such as easy peeling may not be obtained sufficiently, and further, the problem that the print density may not be obtained sufficiently may occur. . On the contrary, when the amount is large, the water resistance is impaired, and when it is wet, the recorded image may bleed or the surface may be peeled off.

Further, as the resin used together with the specific polyvinyl alcohol, the same resin as that for the easy adhesion treatment layer is appropriately selected and used, but in the ink receiving layer, the acrylic ester copolymer is used. Is preferred. As the acrylic acid ester copolymer, a copolymer containing at least an alkyl ester of acrylic acid or methacrylic acid as a monomer component is used as described above, and among them, a copolymer containing at least acrylonitrile as a monomer component as another copolymerization component. Copolymers are preferable, and particularly, a copolymer comprising at least three components using acrylic acid hydroxyalkyl ester as the third monomer component is preferable.
As a specific example of such a copolymer, the monomer composition weight ratio is acrylic acid alkyl ester / acrylonitrile / acrylic acid hydroxyalkyl ester = 50-60.
/ 30 to 45/1 to 5 and, as the alkyl group of acrylic acid alkyl ester and acrylic acid hydroxyalkyl ester, methyl, ethyl, propyl and the like are preferable. Incidentally, also in the ink receiving layer, a water-soluble or water-dispersible resin such as that used in a conventional ink receiving layer can be appropriately used as a binder resin, as in the case of the above-mentioned easy adhesion treatment layer. .

Further, various additives may be used in the ink receiving layer in order to impart or improve various characteristics. Specific examples of the additive used in the ink receiving layer include:
A cationic fixing agent can be used in order to improve the color developability and various properties of the image. As the cationic fixing agent, a polyamine-based resin that is particularly effective for an aqueous pigment ink is preferably used, and specifically, polyvinylbenzyltrimethylammonium halide, polydiacryldimethylammonium halide, polydimethylaminoethylmethacrylate hydrochloride, polyethylene. Examples thereof include imines, dicyandiamide formalin condensates, epichlorohydrin-modified polyalkylamines, polyvinylpyridinium halides, and polyethyleneimine quaternary ammonium salts.

Further, as other additives in the ink receiving layer, pigment dispersants, thickeners, fluidity improvers, defoamers, foam suppressors, mold release agents, foaming agents, penetrants, coloring dyes. A color pigment, a fluorescent whitening agent, an ultraviolet absorber, an antioxidant, an antiseptic, an antifungal agent, a water resistance agent, a wet paper strength enhancer and the like can be appropriately blended as necessary. In addition, these additives may be used in the above-mentioned easy-adhesion treated layer, if necessary.

<Formation of Easy-Adhesion Treatment Layer and Ink Receiving Layer>
The formation of the easy-adhesion treatment layer and the ink receiving layer is a coating solution prepared by dissolving or dispersing the material for forming the layer in water or a suitable solvent, for example, a blade coater, a roll coater, an air knife coater, Various coating devices such as a bar coater, a rod blade coater, a short dwell coater, and a size press are appropriately used in on-machine or off-machine to coat and form on a substrate. The ink absorbing layer may be a single layer or a multilayer including two or more layers.

The coating amount of the easy-adhesion treatment layer and the ink receiving layer is preferably 5 to 30 g / m ² , and particularly 5
-20 g / m < ² > is more preferable. If the coating amount is less than this range, the adhesiveness to the substrate, the ink absorbing property and the fixing property may not be sufficiently obtained, and if the coating amount is more than the above range, the productivity is lowered and the cost is increased.

After the ink receiving layer is applied, it may be finished by using a calendar such as a machine calendar, a TG calendar, a super calendar or a soft calendar.

[0031]

EXAMPLES Next, examples of the present invention and comparative examples will be shown to further clarify the effects of the present invention. Each example and comparative example,
In both cases, the base material was polypropylene synthetic paper having a thickness of 140 μm, and an easy-adhesion treatment layer and an ink receiving layer were sequentially coated on one surface of the base material using a coating liquid having the following solid content blending ratio, and laminated. The sheet is used as an inkjet recording sheet. The coating amount of each layer is 15 after drying.
It was set to g / m ² . In the following description, “part” means “part by weight”.

[0032] <Example 1> ○ Easy adhesion treatment layer ・ Completely saponified PVA (trade name: PVA124, manufactured by Kuraray Co., Ltd.)       Saponification degree 98.0-99.0 mol%, degree of polymerization 2400) 5 parts ・ Styrene-butadiene emulsion       (Product name: PA-0339 manufactured by A & L Japan, Inc.) 65 parts ・ Silica gel (Tokuyama product name: X-37B) 30 parts

[0033] ○ Ink receiving layer ・ Completely saponified PVA (trade name: PVA124, manufactured by Kuraray Co., Ltd.)       Saponification degree 98.0-99.0 mol%, degree of polymerization 2400) 10 parts ・ Acrylic ester copolymer emulsion         (Shin Nakamura Chemical Co., Ltd. product name: PV-303) 24 parts ・ 56 parts of silica gel (trade name: X-37B, manufactured by Tokuyama Corp.) ・ Cationic fixing agent (Sumitomo Chemical Co., Ltd. product name: 784S) 10 parts

[0034] <Example 2> ○ Easy adhesion treatment layer ・ Completely saponified PVA (trade name: PVA117 manufactured by Kuraray Co., Ltd.)       Saponification degree 98.0-99.0 mol%, degree of polymerization 1700) 5 parts ・ Styrene-butadiene emulsion       (Product name: PA-0339 manufactured by A & L Japan, Inc.) 65 parts ・ Silica gel (Tokuyama product name: X-37B) 30 parts

[0035] ○ Ink receiving layer ・ Completely saponified PVA (trade name: PVA117 manufactured by Kuraray Co., Ltd.)       Saponification degree 98.0-99.0 mol%, degree of polymerization 1700) 10 parts ・ Acrylic ester copolymer emulsion       (Shin Nakamura Chemical Co., Ltd. product name: PV-303) 24 parts ・ 56 parts of silica gel (trade name: X-37B, manufactured by Tokuyama Corp.) ・ Cationic fixing agent (Sumitomo Chemical Co., Ltd. product name: 784S) 10 parts

[0036] <Example 3> ○ Easy adhesion treatment layer ・ Completely saponified PVA (Kuraray's trade name: PVA110       Saponification degree 98.0-99.0 mol%, degree of polymerization 1000) 5 parts ・ Styrene-butadiene emulsion       (Product name: PA-0339 manufactured by A & L Japan, Inc.) 65 parts ・ Silica gel (Tokuyama product name: X-37B) 30 parts

[0037] ○ Ink receiving layer ・ Completely saponified PVA (Kuraray's trade name: PVA110       Saponification degree 98.0-99.0 mol%, degree of polymerization 1000) 10 parts ・ Acrylic ester copolymer emulsion         (Shin Nakamura Chemical Co., Ltd. product name: PV-303) 24 parts ・ 56 parts of silica gel (trade name: X-37B, manufactured by Tokuyama Corp.) ・ Cationic fixing agent (Sumitomo Chemical Co., Ltd. product name: 784S) 10 parts

[0038] <Example 4> ○ Easy adhesion treatment layer ・ Partially saponified PVA (trade name: PVA224 manufactured by Kuraray Co., Ltd.)       Saponification degree 86.5 to 89.5 mol%, degree of polymerization 2400) 5 parts ・ Styrene-butadiene emulsion       (Product name: PA-0339 manufactured by A & L Japan, Inc.) 65 parts ・ Silica gel (Tokuyama product name: X-37B) 30 parts

[0039] ○ Ink receiving layer ・ Partially saponified PVA (trade name: PVA224 manufactured by Kuraray Co., Ltd.)       Saponification degree 86.5 to 89.5 mol%, degree of polymerization 2400) 10 parts ・ Acrylic ester copolymer emulsion       (Shin Nakamura Chemical Co., Ltd. product name: PV-303) 24 parts ・ 56 parts of silica gel (trade name: X-37B, manufactured by Tokuyama Corp.) ・ Cationic fixing agent (Sumitomo Chemical Co., Ltd. product name: 784S) 10 parts

[0040] <Example 5> ○ Easy adhesion treatment layer ・ Completely saponified PVA (trade name: PVA124, manufactured by Kuraray Co., Ltd.)       Saponification degree 98.0-99.0 mol%, degree of polymerization 2400) 5 parts ・ Styrene-acrylic copolymer emulsion     (Product name of Clariant Polymer Co., Ltd .: Movinyl 860) 65 parts ・ Silica gel (Tokuyama product name: X-37B) 30 parts

[0041] ○ Ink receiving layer ・ Completely saponified PVA (trade name: PVA124, manufactured by Kuraray Co., Ltd.)       Saponification degree 98.0-99.0 mol%, degree of polymerization 2400) 10 parts ・ Acrylic ester copolymer emulsion         (Shin Nakamura Chemical Co., Ltd. product name: PV-303) 24 parts ・ 56 parts of silica gel (trade name: X-37B, manufactured by Tokuyama Corp.) ・ Cationic fixing agent (Sumitomo Chemical Co., Ltd. product name: 784S) 10 parts

[0042] <Example 6> ○ Easy adhesion treatment layer ・ Completely saponified PVA (trade name: PVA124, manufactured by Kuraray Co., Ltd.)       Saponification degree 98.0-99.0 mol%, degree of polymerization 2400) 5 parts ・ Ester / ether urethane emulsion       (Daiichi Kogyo Seiyaku Co., Ltd. product name: Superflex 150) 65 parts ・ Silica gel (Tokuyama product name: X-37B) 30 parts

[0043] ○ Ink receiving layer ・ Completely saponified PVA (trade name: PVA124, manufactured by Kuraray Co., Ltd.)       Saponification degree 98.0-99.0 mol%, degree of polymerization 2400) 10 parts ・ Acrylic ester copolymer emulsion         (Shin Nakamura Chemical Co., Ltd. product name: PV-303) 24 parts ・ 56 parts of silica gel (trade name: X-37B, manufactured by Tokuyama Corp.) ・ Cationic fixing agent (Sumitomo Chemical Co., Ltd. product name: 784S) 10 parts

[0044] <Example 7> ○ Easy adhesion treatment layer ・ Partially saponified PVA (trade name: PVA217 manufactured by Kuraray Co., Ltd.)       Saponification degree 87.0 to 89.0 mol%, degree of polymerization 1700) 5 parts ・ Styrene-butadiene emulsion       (Product name: PA-0339 manufactured by A & L Japan, Inc.) 65 parts ・ Silica gel (Tokuyama product name: X-37B) 30 parts

[0045] ○ Ink receiving layer ・ Partially saponified PVA (trade name: PVA217 manufactured by Kuraray Co., Ltd.)       Saponification degree 87.0 to 89.0 mol%, degree of polymerization 1700) 10 parts ・ Acrylic ester copolymer emulsion       (Shin Nakamura Chemical Co., Ltd. product name: PV-303) 24 parts ・ 56 parts of silica gel (trade name: X-37B, manufactured by Tokuyama Corp.) ・ Cationic fixing agent (Sumitomo Chemical Co., Ltd. product name: 784S) 10 parts

[0046] <Comparative Example 1> ○ Easy adhesion treatment layer ・ Partially saponified PVA (trade name: PVA210, manufactured by Kuraray Co., Ltd.)       Saponification degree 87.0 to 89.0 mol%, degree of polymerization 1000) 5 parts ・ Styrene-butadiene emulsion       (Product name: PA-0339 manufactured by A & L Japan, Inc.) 65 parts ・ Silica gel (Tokuyama product name: X-37B) 30 parts

[0047] ○ Ink receiving layer ・ Partially saponified PVA (trade name: PVA210, manufactured by Kuraray Co., Ltd.)       Saponification degree 87.0 to 89.0 mol%, degree of polymerization 1000) 10 parts ・ Acrylic ester copolymer emulsion       (Shin Nakamura Chemical Co., Ltd. product name: PV-303) 24 parts ・ 56 parts of silica gel (trade name: X-37B, manufactured by Tokuyama Corp.) ・ Cationic fixing agent (Sumitomo Chemical Co., Ltd. product name: 784S) 10 parts

[0048] <Comparative example 2> ○ Easy adhesion treatment layer ・ Completely saponified PVA (trade name: PVA124, manufactured by Kuraray Co., Ltd.)       Saponification degree 98.0-99.0 mol%, degree of polymerization 2400) 5 parts ・ Styrene-butadiene emulsion       (Product name: PA-0339 manufactured by A & L Japan, Inc.) 65 parts ・ Silica gel (Tokuyama product name: X-37B) 30 parts

[0049] ○ Ink receiving layer ・ Acrylic ester copolymer emulsion       (Shin Nakamura Chemical Co., Ltd. product name: PV-303) 34 parts ・ 56 parts of silica gel (trade name: X-37B, manufactured by Tokuyama Corp.) ・ Cationic fixing agent (Sumitomo Chemical Co., Ltd. product name: 784S) 10 parts

[0050] <Comparative example 3> ○ Easy adhesion treatment layer ・ Styrene-butadiene emulsion       (Product name: PA-0339 manufactured by A & L Japan, Inc.) 65 parts ・ Silica gel (Tokuyama product name: X-37B) 30 parts

[0051] ○ Ink receiving layer ・ Completely saponified PVA (trade name: PVA124, manufactured by Kuraray Co., Ltd.)       Saponification degree 98.0-99.0 mol%, degree of polymerization 2400) 10 parts ・ Acrylic ester copolymer emulsion       (Shin Nakamura Chemical Co., Ltd. product name: PV-303) 34 parts ・ 56 parts of silica gel (trade name: X-37B, manufactured by Tokuyama Corp.) ・ Cationic fixing agent (Sumitomo Chemical Co., Ltd. product name: 784S) 10 parts

[0052] <Comparative example 4> ○ Easy adhesion treatment layer ・ Completely saponified PVA (trade name: PVA117 manufactured by Kuraray Co., Ltd.)       Saponification degree 98.0-99.0 mol%, degree of polymerization 1700) 5 parts ・ Styrene-butadiene emulsion       (Product name: PA-0339 manufactured by A & L Japan, Inc.) 65 parts ・ Silica gel (Tokuyama product name: X-37B) 30 parts

[0053] ○ Ink receiving layer ・ Completely saponified PVA (trade name: PVA117 manufactured by Kuraray Co., Ltd.)       Saponification degree 98.0-99.0 mol%, degree of polymerization 1700) 34 parts ・ 56 parts of silica gel (trade name: X-37B, manufactured by Tokuyama Corp.) ・ Cationic fixing agent (Sumitomo Chemical Co., Ltd. product name: 784S) 10 parts

[0054] <Comparative Example 5> ○ Easy adhesion treatment layer ・ Completely saponified PVA (trade name: PVA117 manufactured by Kuraray Co., Ltd.)       Saponification degree 98.0-99.0 mol%, degree of polymerization 1700) 70 parts ・ Silica gel (Tokuyama product name: X-37B) 30 parts

[0055] ○ Ink receiving layer ・ Completely saponified PVA (trade name: PVA117 manufactured by Kuraray Co., Ltd.)       Saponification degree 98.0-99.0 mol%, degree of polymerization 1700) 10 parts ・ Acrylic ester copolymer emulsion       (Shin Nakamura Chemical Co., Ltd. product name: PV-303) 24 parts ・ 56 parts of silica gel (trade name: X-37B, manufactured by Tokuyama Corp.) ・ Cationic fixing agent (Sumitomo Chemical Co., Ltd. product name: 784S) 10 parts

[0056] <Comparative example 6> ○ Easy adhesion treatment layer ・ Completely saponified PVA (trade name: PVA117 manufactured by Kuraray Co., Ltd.)       Saponification degree 98.0-99.0 mol%, degree of polymerization 1700) 5 parts ・ Styrene-butadiene emulsion       (Product name: PA-0339 manufactured by A & L Japan) 45 copies 50 parts of silica gel (Tokuyama product name: X-37B)

[0057] ○ Ink receiving layer ・ Completely saponified PVA (trade name: PVA117 manufactured by Kuraray Co., Ltd.)       Saponification degree 98.0-99.0 mol%, degree of polymerization 1700) 10 parts ・ Acrylic ester copolymer emulsion       (Shin Nakamura Chemical Co., Ltd. product name: PV-303) 40 parts ・ 40 parts of silica gel (Tokuyama's trade name: X-37B) ・ Cationic fixing agent (Sumitomo Chemical Co., Ltd. product name: 784S) 10 parts

With respect to the ink jet recording sheets of the above Examples and Comparative Examples, the layer strength was evaluated by the following method. Further, using a commercially available inkjet printer (manufactured by Seiko Epson: product name MC-2000C), four color batches of mixed color black, cyan, magenta, and yellow are printed, and the print density is measured.
The printing density and the ink absorbency were evaluated by the following methods, and the results are shown in Table 1.

[0059]

[Table 1]

The surface strengths 1, 2 and 3, print density and ink absorbency were evaluated by the following evaluation methods.

Surface Strength 1 Cellophane tape was attached to the surface of the prepared ink jet recording sheet, rubbed with a finger three times and then peeled off, and breakage and peeling of the surface layer were evaluated. A sample with almost no peeling or a slight amount of peeling is ○, a sample with some peeling but no problem in practical use is △, the surface layer of the part where the cellophane tape is adhered is considerably peeled, and the lower layer is easily peeled. The case where the adhesive treatment layer or the base material was exposed and was inferior in practical use was marked with x.

Surface Strength 2 The surface of the prepared ink jet recording sheet was rubbed with a ball-point pen to evaluate breakage and peeling of the surface. Practical writing, even if it is not peeled off even if it is rubbed with more force ○, it is not peeled off with practical writing, but peeled off with more force △, practical writing Those that would peel off were marked with x.

Surface Strength 3 0.5 ml of tap water was dropped on the surface of the prepared ink jet recording paper, and the surface was rubbed with a finger three times, and after drying, the surface was broken and peeled off. The case where the surface was not peeled off was excellent, and the case where there was some peeling, but there was no problem in practical use was Δ, and the case where the surface was peeled only by rubbing with a finger and there was a problem in practical use was evaluated as X.

Print Density The reflection density of the printed color batch of the mixed color black was measured with a spectrophotometer (Product name SPM50 manufactured by Gretag Macbeth Co.), and the measured numerical value was evaluated as ○, and less than 1.40 was evaluated as ×. did.

Ink absorbency: Good quality plain paper was placed on a sample immediately after printing of each color batch of color, and judgment was made based on the degree of transfer of the ink to the good quality plain paper and the degree of bleeding of the contour of the color batch. A sample having no transfer or contour blurring was evaluated as O, a sample having a slight transfer but no blurring was evaluated as Δ, and a sample having clear transfer or contour blurring was evaluated as X.

From the above evaluation results, in Examples 1 to 7,
An ink jet recording sheet having excellent surface strength, good ink absorption and high printing density can be obtained.
Examples 1, 5 and 6 which contained polyvinyl alcohol having a saponification degree of 90 mol% or more in both the easy-adhesion treatment layer and the ink receiving layer showed extremely high surface strength. Comparative Examples 1 and 2 containing polyvinyl alcohol having a low degree of polymerization and a low degree of saponification were inferior in surface strength, printing density and ink absorbency. Comparative Example 2 in which the easy-adhesion-treated layer contains polyvinyl alcohol having a polymerization degree of 2000 or more and a saponification degree of 90 mol% or more, but does not contain the polyvinyl alcohol.
Has good strength, but is inferior in print density and ink absorption,
Comparative Example 3 in which the easy-adhesion-treated layer does not contain polyvinyl alcohol and the ink-receiving layer contains polyvinyl alcohol having a polymerization degree of 1500 or more and a saponification degree of 90 mol% or more, has good ink absorbability and concentration, but is poor in strength. Became.

[0067]

As described above, according to the present invention, the polymerization degree is 1500 or more or the saponification degree is 90 mo according to the present invention.
By containing 1% or more of polyvinyl alcohol, and one or more selected from styrene-butadiene copolymer, acrylate copolymer, and polyurethane resin in the easy-adhesion treatment layer and the ink receiving layer, It is possible to obtain an inkjet recording sheet in which the surface strength of the inkjet recording medium is extremely effectively improved without impairing good recording characteristics such as ink absorbency and color developability. Further, by using the above specific laminated structure, it is possible to apply to base materials such as olefin resin laminated paper, a sheet made of various synthetic fibers, and synthetic resin film, which have conventionally had a problem in the adhesiveness of the ink receiving layer. Excellent adhesiveness was obtained, excellent surface strength was achieved, and these substrates could be sufficiently used. Therefore, in particular, whether indoors or outdoors,
It can be sufficiently used for applications requiring surface strength such as signboards, posters, bus wrapping, and interior / exterior of events, and the application is expected to expand.

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Claims (5)

[Claims] 1. An easy-adhesion treatment layer containing a pigment and a resin and an ink receiving layer are sequentially laminated on at least one side of a base material, and the resin of the easy-adhesion treatment layer and the ink receiving layer is provided. Polymerization degree over 1500 or saponification degree 90mo
1% or more of polyvinyl alcohol and at least one selected from a styrene-butadiene copolymer, an acrylic ester copolymer, and a polyurethane resin, and the blending ratio of the pigment is an easy-adhesion treatment. An ink jet recording sheet characterized by having more ink receiving layers than layers. 2. The ink jet recording sheet according to claim 1, wherein the content of polyvinyl alcohol in the easily adhesive treatment layer is 1 to 30% by weight. 3. The inkjet recording sheet according to claim 1, wherein the content of polyvinyl alcohol in the ink receiving layer is 5 to 50% by weight. 4. The ink jet recording sheet according to claim 1, wherein the content of the pigment in the easy adhesion treatment layer is 5 to 50% by weight. 5. The ink jet recording sheet according to claim 1, wherein the content of the pigment in the ink receiving layer is 40 to 95% by weight.