JPH11301098A - Ink jet recording medium and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make compatible absorptiveness and water resistance by laminating a water absorptive layer consisting of water absorptive time particles and hydrophobic binder resin, and an ink receptor layer consisting of resin made of thermosetting a cationic modified acrylic copolymer and polyvinylacetal resin with an epoxy compound on a support. SOLUTION: In the ink jet recording medium 1 having opposite characteristics of wettability, a dyeable property and absorptiveness, and water resistance, a drying property and an antiblocing property are made compatible, and it is formed by laminating a water absorptive layer 3 comprising of at least water absorptive fine particle and hydrophobic binder resin, and an ink receptor layer 4 comprising resin made by thermosetting cationic modified acrylic copolymer and polyvinyl acetal resin with an epoxy compound on a support 2. In this case, as water absorptive resin fine particles of the water absorptive layer 3, there is used singly any one of polyacrylic acid or polyacrylic acid salt, or fine particles consisting of these copolymeric cross-linked compounds.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium for an ink jet printer, and more particularly, to a recording medium having both wettability, absorptivity and water resistance.

[0002]

2. Description of the Related Art In recent years, various types of printers for computer output have become widespread. Above all, an ink jet printer is excellent in quietness, cost, and image quality, can reproduce a full-color image with high quality, has excellent performance not found in other systems, and can be expected to spread further. On the other hand, paper is often used for printer paper, and plastic films and synthetic papers are also used for applications requiring smooth images utilizing their smooth surface and transparency.

[0003] Ink-jet inks include:
In order to prevent clogging of the ink nozzle, a slow-drying ink in which a water-soluble dye or the like is dissolved in an aqueous solvent is used. Therefore,
Good if the recording paper is water-absorbent, such as paper, but if it is non-water-absorbing such as a plastic film, the ink will have poor drying properties after printing. A receiving layer is provided.

[0004]

However, a structure in which an ink receiving layer is provided on a support such as a plastic film or the like has not been able to obtain satisfactory performance. That is,
In order to improve the wettability, dyeing properties, or absorbability of the slow-drying ink, a method of forming the ink receiving layer from a water-soluble resin, a hydrophilic resin, or the like has been proposed. Or the ink receiving layer becomes wet and sticky in an environment of high humidity, and there is a problem that blocking occurs when the recording media are stacked, or that the ink is poorly dried and easily stained when touched by hand after printing. . The wettability, the dyeing property and the absorptivity and the water resistance, the drying property and the blocking resistance are properties that are contradictory to each other, and a satisfactory performance satisfying these properties has not been obtained.

The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to reduce the ink wettability and dyeability of the ink receiving layer and the water resistance of the ink receiving layer. It is an object of the present invention to provide an ink jet recording medium that is compatible with the ink jet recording medium, and that is particularly excellent in transparency.

[0006]

Means for Solving the Problems In order to solve the above problems, the invention according to claim 1 of the present invention is directed to a water absorbing layer comprising at least a water absorbing resin fine particle and a hydrophobic binder resin on a support, An ink jet recording medium characterized in that a cation-modified acrylic copolymer and a polyvinyl acetal resin are heat-cured with an epoxy compound and an ink receiving layer made of a resin is laminated in this order. According to this, the image formed by the ink receiving layer can be excellent in drying property and can have high definition. The ink receiving layer also has excellent transparency.

A second aspect of the present invention is based on the ink jet recording medium according to the first aspect, wherein the water-absorbing resin particles of the water-absorbing layer are made of either polyacrylic acid or polyacrylate alone or a mixture thereof. It is characterized by comprising a crosslinked copolymer. According to this, it is possible to absorb water in the ink jet ink.

A third aspect of the present invention is based on the ink jet recording medium according to the first or second aspect, wherein the water-absorbent resin fine particles of the water-absorbing layer have an average particle size of 10 to 500.
It is characterized in that it is in the range of μm and the water absorption ratio is in the range of 100 to 1000 times. According to this, it is possible to quickly absorb the water in the ink in the ink jet recording and improve the drying property.

A fourth aspect of the present invention is based on the ink jet recording medium according to any one of the first to third aspects, wherein the binder resin of the water-absorbing layer comprises an alcohol, toluene,
It is characterized by being soluble in an organic solvent of either methyl ethyl ketone or ethyl acetate and being hydrophobic. According to this, the absorbent resin fine particles can be dispersed to form a coating liquid.

A fifth aspect of the present invention is based on the ink jet recording medium according to any one of the first to fourth aspects, wherein the monomer component of the cation-modified acrylic copolymer in the ink receiving layer is at least methyl methacrylate or acrylic. It is characterized by comprising either ethyl acrylate or quaternary ammonium salt of dialkylaminoethyl methacrylate. According to this, methyl methacrylate is water resistant,
Ethyl acrylate contributes to the flexibility, and dialkylaminoethyl methacrylate quaternary ammonium salt contributes to the fixability of the dye. As a result, the above-mentioned properties (ink wetting and dyeing properties, water resistance, And transparency) can be more preferably improved.

A sixth aspect of the present invention is based on the ink jet recording medium according to any one of the first to fifth aspects, wherein the polyvinyl acetal resin of the ink receiving layer comprises polyvinyl alcohol having a saponification degree of 70 to 90%. 5-20mo
It is characterized by being 1% acetalized. According to this, the ink absorbency and the water resistance can be achieved in a well-balanced manner, which is preferable. If the degree of saponification of the polyvinyl alcohol is less than 70% or more than 90%, the ink absorbency is significantly reduced, and if the degree of acetalization of the polyvinyl alcohol is less than 5 mol%, the water resistance is significantly reduced. , Acetalization degree is 20m
If the amount exceeds ol%, the ink absorbency is also remarkably reduced, which is not preferable.

[0012] The invention of claim 7 is based on the ink jet recording medium according to any one of claims 1 to 6, wherein the epoxy compound of the ink receiving layer is aliphatic, water-soluble, and It is characterized by being at least functional.
According to this, the resin crosslink density at the time of curing is increased, and an excellent effect is obtained because the water resistance is large.

According to an eighth aspect of the present invention, there is provided the ink jet recording medium according to any one of the first to seventh aspects, wherein the cation-modified acrylic copolymer and the polyvinyl acetal resin of the ink receiving layer are each composed of water and alcohol. And dissolved in a mixed solvent. According to this, it is excellent in that both the ink jet absorbability and the water resistance can be achieved.

According to a ninth aspect of the present invention, at least a water-absorbing layer composed of fine particles of a water-absorbing resin and a hydrophobic binder resin, a cation-modified acrylic copolymer and a polyvinyl acetal resin are thermally cured with an epoxy compound on a support. And an ink receiving layer made of a cured resin in this order. More preferably, the material according to any one of claims 1 to 8 is used.

[0015]

In order to solve the above-mentioned problems and to achieve the object, an ink jet recording medium of the present invention has a water absorbing layer comprising fine particles of water absorbing resin and a hydrophobic binder resin on at least one surface of a support. An ink receiving layer composed of a cation-modified acrylic copolymer having a group that reacts with an epoxy group and a resin obtained by thermosetting a polyvinyl acetal resin with a polyepoxy compound is sequentially laminated on the water absorbing layer. In the above-mentioned ink jet recording medium, the support has a water-absorbing layer containing water-absorbing resin fine particles on the support to improve the drying property of the ink-receiving layer, and further, usually, a cation-modified acrylic having excellent ink absorption but poor water resistance. By sequentially laminating an ink receiving layer obtained by thermally curing a copolymer and a polyvinyl acetal resin with an epoxy compound, it was found that an ink jet recording medium having excellent performance in both ink absorption and water resistance was obtained, and to complete the present invention. Reached.

The water-absorbing layer in the present invention is a layer that absorbs water in the ink-jet ink. In the present invention, specific water-absorbing resin fine particles are used in the layer. Such water-absorbent resin fine particles have a constitution mainly composed of a crosslinked product of polyacrylic acid or polyacrylate alone or copolymer. Further, the ink receiving layer is a layer that receives ink, and in the present invention, a specific resin is used for the layer to achieve both the dyeing property and wettability of the ink and the water resistance. Such a resin is composed of a cation-modified acrylic copolymer having a group that reacts with an epoxy group and a resin obtained by thermosetting a polyvinyl acetal resin with an epoxy compound.

The water-absorbing resin fine particles of the water-absorbing layer in the present invention may be polyacrylic acid or polyacrylate alone or copolymer crosslinked, N-polyvinylacetamide crosslinked, starch-acrylate kraft copolymer. Crosslinked product, isobutylene-maleic anhydride copolymer,
A water-absorbing polymer such as a crosslinked product of polyethylene oxide may be mentioned. Among them, a crosslinked product of polyacrylic acid or polyacrylate alone or a copolymer is preferable.

As the binder resin for the water-absorbing layer, a hydrophobic resin which is dissolved in an organic solvent such as alcohols, toluene, methyl ethyl ketone, and ethyl acetate and is used, for example, poly (meth) acrylate, poly (meth) acrylate ) Acrylic polymers of ethyl acrylate, poly (propyl meth) acrylate and poly (butyl meth) acrylate.

Each of the water-absorbent resin fine particles and the binder resin described above uses one or a mixture of two or more solvents such as toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, and xylene.
Used as a coating solution of の 50% by weight solution. In use, the composition of the water-absorbing layer coating liquid is such that the equivalent ratio of the water-absorbent resin fine particles / binder resin is mixed at about 1/3 to 2/1, and diluted if necessary. If the amount of the water-absorbent resin particles is too large, the adhesion to the support is reduced, and if the amount is small, the hydrophobicity of the binder resin is hindered, and the water absorption is significantly reduced.

The thickness of the water absorbing layer is usually about 10 to 50 μm, preferably about 20 to 30 μm. If the thickness is too thin, the water absorption is insufficient, and if it is too thick, the cost increases and the curl increases.

The water-absorbing layer is formed by applying a coating liquid obtained by mixing the above water-absorbing resin fine particles and a binder resin at an appropriate equivalent ratio.
At least one surface of the support may be coated by a known coating means such as a gravure coat, a roll coat, and a wire bar coat.

As the acrylic copolymer of the ink receiving layer in the present invention, it is preferable that the monomer constituting the copolymer is an acrylic monomer having a quaternary ammonium base particularly in the cation-modified portion. In addition, an acrylic monomer having a functional group such as a hydroxy group is preferably used for a portion having a group that reacts with an epoxy group, and a hydrophobic monomer made of (meth) acrylic acid ester or the like is used as a portion having hydrophobicity. Is desirable.

Examples of the acrylic monomer having a quaternary ammonium base include dimethylaminoethyl (meth) acrylate, diethylamino (meth) acrylate, diethanolamino (meth) acrylate, dipropylamino (meth) acrylate, and dipropanolamino. (Meth) acrylate, dibutylamino (meth)
(Meth) having a tertiary amino group such as acrylate
There is a quaternized monomer of an acrylate monomer. Further, as the acrylic monomer having a quaternary ammonium base, a monomer having a functional group such as a carboxyl group or a hydroxyl group such as acrylic acid, methacrylic acid, or a mono (meth) acrylate of these acids and a glycol such as ethylene glycol; Glycidyltrimethylammonium chloride, 3-chloro-2-hydroxypropyltrimethylammonium chloride,
Monomers reacted with a reactive quaternary ammonium salt such as chloro-2-hydroxypropyltriethanolammonium chloride, glycidyldimethylbenzylammonium chloride, and glycidyldimethylbutylammonium chloride are exemplified.

On the other hand, acrylic monomers having a group that reacts with an epoxy group include, for example, acrylic acid and methacrylic acid as monomers having a carboxyl group, and these monomers and ethylene glycol, propylene glycol, glycerin, pentaerythritol, etc. Esterified with polyhydric alcohol, ethylenediamine,
Examples include amidated products with polyvalent amines such as propylene diamine, acrylamide, methacrylamide and the like.

Examples of the hydrophobic monomer comprising (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate and the like. (Meth) acrylic acid ester or acrylamide,
Examples include monomers such as acrylonitrile, vinyl acetate, vinyl chloride, and styrene.

The polyvinyl acetal resin of the ink receiving layer in the present invention is preferably a polyvinyl alcohol having a saponification degree of 70 to 90% and acetalized at 5 to 20 mol%. Degree of saponification of polyvinyl alcohol is 7
If it is less than 0% or more than 90%, the ink absorbency is remarkably reduced. If the degree of acetalization of polyvinyl alcohol is 5 mol% or less, the water resistance is remarkably reduced. Properties are significantly reduced.

The acetal part of the polyvinyl acetal resin is formal, methylal, ethylal,
Proparl and butyral are preferred.

As the epoxy compound for curing the cation-modified acrylic copolymer and the polyvinyl acetal resin as described above, a bifunctional or more epoxy compound having two or more epoxy groups is used. Examples of such an epoxy compound include polyglycerol polyglycidyl ether, pentaethylitol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, resorcinol diglycidyl ether, and polypropylene glycol diglycol. It is an aliphatic and water-soluble epoxy compound such as glycidyl ether.

The above-mentioned cation-modified acrylic copolymer, polyvinyl acetal resin (main agent) and epoxy compound (curing agent) are all water, methanol, ethanol, isopropyl alcohol, acetone, methyl ethyl ketone, methyl isobutyl ketone, acetic acid It is used as a coating liquid of a 10 to 50% by weight solution using one or two or more kinds of mixed solvents such as ethyl, toluene and xylene. In use, the equivalent ratio of the base agent / hardener is about 1/0 to 1/2.
And dilute if necessary.

It is preferable to add a filler to the ink receiving layer in order to improve transportability and blocking resistance. The amount of addition should be within a range that does not impair the transparency for use in transparent images such as OHP.

Examples of such a filler include organic fine particles such as polymethyl methacrylate, polyvinylpyrrolidone, polystyrene, fluororesin vinyl resins, polyolefin resins such as polyethylene and polypropylene, and thermoplastic resins such as polyamide. , A fine particle made of a thermosetting resin such as a polybenzoguanamine resin or a urea resin, having a particle size of 0.1 to 30 μm, preferably 0.1 to 20 μm.
μm. Usually 0.1 in the ink receiving layer
About 20 wt% is contained. If too little, transportability,
Sufficient blocking resistance cannot be obtained. In the case of a transparent image such as OHP, if the amount is too large, the transparency is impaired.
Less than 0 wt% is good.

As the inorganic fine particles, clay, calcium carbonate, barium sulfate, aluminum hydroxide, talc, bentonite, titanium oxide, etc., and silicic anhydride, hydrous silicic acid, hydrous calcium silicate, and hydrous calcium oxide known as colloidal silica, etc. The use of inorganic fine particles having a particle size of usually about 10 to 300 nm, such as white carbon such as aluminum silicate or alumina sol, diffuses the ink printed on the ink receiving layer appropriately and is effective in forming high quality images.
Such inorganic fine particles are used in the ink receiving layer in an amount of 5 to 90 watts.
About t% is contained. In the case of a transparent image such as an OHP, the content is slightly reduced, and in the case of an opaque image, there is also a meaning of providing whiteness, and the content is increased.

In addition, the ink receiving layer may have, depending on the purpose,
In addition to the above fillers, other resins other than those mentioned above, or surfactants, ultraviolet absorbers, antioxidants, PH adjusters, defoamers and other additives are appropriately mixed within a range not departing from the performance. Is also good.

The thickness of the ink receiving layer is usually from 1 to 50 μm.
m, preferably about 3 to 20 μm. If the thickness is too small, the dyeing properties will be insufficient, and the drying property and the anti-blocking property will be reduced. Conversely, if the thickness is too large, the cost will increase and the curl will increase.

The ink receiving layer is formed by coating a coating solution obtained by mixing the above-mentioned base agent and curing agent at an appropriate equivalent ratio on at least one surface of a support by a known coating method such as gravure coating, roll coating, wire bar coating and the like. What is necessary is just to apply by means.

Examples of the support for the ink jet recording medium include polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polystyrene, polymethyl methacrylate, polycarbonate, cellophane, cellulose acetate, and polyarylate. A film or plate made of a resin such as polyether sulfone can be used. OHP for inkjet recording media
If it is intended for use, it is transparent, especially polyethylene terephthalate film, rigid polyvinyl chloride film,
Use a polypropylene film, a triacetate film, or the like. Also, a glass plate or the like can be used. On the other hand, OHP
If it is not a transparent image application such as a transparent image, an opaque support such as white may be used, and various papers such as synthetic paper, high-quality paper, art paper, coated paper, cast coated paper, and paperboard can also be used.

The thickness of the support is appropriately selected in consideration of the strength in accordance with the application and is not particularly limited.
It is about 00 μm. In addition, the surface of the support 2 may be subjected to a corona discharge treatment or a known easy adhesion treatment such as an anchor layer made of polyurethane resin or the like for the purpose of improving the adhesion of the water absorbing layer provided on the surface.

The aqueous ink that can be used in the ink jet recording medium of the present invention is a known ink jet ink, and is usually a water-soluble dye, a wetting agent, a dye solubilizing agent, a preservative, water, and a water-miscible ink. It consists of an organic solvent and the like.

<Function> As described above, in the ink jet recording medium of the present invention, a specific polyacrylic acid or polyacrylic acid salt alone or a copolymer crosslinked product is formed on a support as fine particles of water-absorbing resin. The water-absorbing layer made of a hydrophobic binder resin improves the ink drying property at the time of printing and prevents bleeding and blurring of an image. Also, by using a resin obtained by thermosetting a specific acrylic copolymer and a polyvinyl acetal resin for the ink receiving layer, both wettability, dyeing properties, and water resistance can be achieved. The cation-modified portion of the acrylic copolymer to be cured and the hydroxy group of the polyvinyl acetal resin mainly have ink absorbency, while being cured by the polyepoxy compound, so that water resistance is obtained. No melting or stickiness occurs.

Particularly, the water-absorbent resin fine particles are made of a crosslinked product of polyacrylic acid or polyacrylate alone or in a copolymer, and have an average particle size of 10 to 500 μm and a water absorption ratio of 100 to 1000 times. By this, the drying property at the time of printing is improved, and there is an effect of preventing bleeding and blurring.

[0041]

The present invention will be described below more specifically with reference to examples and comparative examples. In the following description, “parts” is based on weight and solid content unless otherwise specified.

Examples 1 to 12 and Comparative Examples 1 to 3 As a support, a polyethylene terephthalate film (trade name; Lumirror E) having a surface having a thickness of 100 μm and having been subjected to an easy adhesion treatment was used.
63S, manufactured by Toray Industries, Inc.).
And the water-absorbing layer coating composition having the composition described in Table 2 was applied by bar coating so that the film thickness after drying was 20 μm,
After drying at 100 ° C. for 3 minutes, an ink receiving layer coating composition having the composition shown in Tables 3 and 4 was applied by bar coating so that the film thickness after drying was 15 μm.
For 3 minutes to obtain an ink jet recording medium having a layer constitution shown in Table 5.

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

[Table 3]

[0046]

[Table 4]

[0047]

[Table 5]

The following items were evaluated for the ink jet recording medium obtained as described above. In addition, printing was performed by a Canon inkjet printer (BJC-4).
20J), and a recorded image was formed with four color inks of yellow, magenta, cyan, and black. The evaluation results are shown in Table 3.

[Ink Absorption] Immediately after printing, the degree of outflow of ink when the recording portion of the recorded matter was rubbed with a finger was evaluated. ◎: Completely dried and did not flow at all. ；: The recording part is slightly wet, though it does not flow out. Δ: A small amount of outflow is observed. ×: A large amount of outflow is observed.

[Ink drying property] The drying condition (swelling of the resin) on the recording portion was visually confirmed. A: There is no swelling of the resin immediately after recording. ；: Resin swelling disappeared within minutes after recording. Δ: Swelling of the resin disappeared within one hour after recording. ×: The resin remains swollen even after 1 hour from the recording.

[Water resistance (recording part)] Water was dropped on the recording part with a dropper and immediately wiped lightly with gauze. A: Ink hardly flows out. ；: Ink slightly leaked, but no significant change in color tone. Δ: Inflow of ink and change in color tone are observed. ×: The coating film is dissolved, and the ink is also peeled off.

[Water resistance (unrecorded portion)] Water was dropped on the coating film with a dropper and immediately wiped lightly with gauze. A: There is almost no damage to the coating film. ；: Slight damage to the coating film, but no problem in practical use. Δ: dissolves in a part of the coating film. ×: Most of the coating film is dissolved.

[0053]

[Table 6]

[0054]

As is clear from the results of Tables 1 to 6,
The ink jet recording media obtained in Examples 1 to 12 of the present invention have a water absorbing layer, and thus are excellent in ink drying properties and can obtain clear images without bleeding or blurring. In general, according to the present invention, an ink-receiving layer having excellent wettability and dyeability of the ink-receiving layer, and a water-resistant surface, which can achieve both of these, and particularly excellent in transparency, can be obtained. Could be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an embodiment of an ink jet recording medium according to the present invention using a cross-sectional view thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ink jet recording medium 2 ... Support 3 ... Water absorption layer 4 ... Ink receiving layer

Continued on the front page (72) Inventor Jiro Watanabe 1-5-1, Taito, Taito-ku, Tokyo Letterpress Printing Co., Ltd.

Claims (9)

[Claims] 1. A support comprising at least a water-absorbing layer comprising water-absorbing resin fine particles and a hydrophobic binder resin on a support, and a resin obtained by thermosetting an cation-modified acrylic copolymer and a polyvinyl acetal resin with an epoxy compound. An ink jet recording medium, wherein an ink receiving layer is laminated in this order. 2. The water-absorbing resin fine particles of the water-absorbing layer are made of either polyacrylic acid or polyacrylate alone or a cross-linked copolymer thereof. Ink jet recording medium. 3. The water-absorbent resin fine particles of the water-absorbent layer have an average particle size in the range of 10 to 500 μm and a water absorption ratio of 1
3. The inkjet recording medium according to claim 1, wherein the ratio is in the range of 00 to 1000 times. 4. The method according to claim 1, wherein the binder resin of the water-absorbing layer is dissolved in an organic solvent of alcohols, toluene, methyl ethyl ketone or ethyl acetate and is hydrophobic. An inkjet recording medium according to any one of the above. 5. A method according to claim 1, wherein the monomer component of the cation-modified acrylic copolymer of the ink receiving layer comprises at least one of methyl methacrylate, ethyl acrylate and quaternary ammonium salt of dialkylaminoethyl methacrylate. The inkjet recording medium according to any one of claims 1 to 4, wherein: 6. The method according to claim 1, wherein the polyvinyl acetal resin of the ink receiving layer is obtained by converting a polyvinyl alcohol having a saponification degree of 70 to 90% into an acetal of 5 to 20 mol%. 3. The ink jet recording medium according to claim 1. 7. The ink jet recording medium according to claim 1, wherein the epoxy compound of the ink receiving layer is aliphatic, water-soluble, and bifunctional or higher. . 8. The cation-modified acrylic copolymer and the polyvinyl acetal resin of the ink receiving layer,
The inkjet recording medium according to any one of claims 1 to 7, wherein the inkjet recording medium is dissolved in a mixed solvent of water and alcohol. 9. A support comprising at least a water-absorbing layer composed of fine particles of a water-absorbing resin and a hydrophobic binder resin, and a resin obtained by thermosetting an cation-modified acrylic copolymer and a polyvinyl acetal resin with an epoxy compound. A method for manufacturing an ink jet recording medium, comprising laminating an ink receiving layer in this order.