JP2002154264A - Ink jet recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording sheet renovated to deal with the oozing of ink which occurs when the sheet is conserved in such a state that its printed face is laminated or touch before vaporization of the moisture content of the ink following ink jet printing. SOLUTION: The ink jet recording sheet has a recording layer formed on one of the surfaces of a film support and a back coat layer containing a water swelling polymer hardened on the opposite surface to the recording layer through the support. The recording layer is a void layer containing a hardened hydrophilic polymer and fine particles, and the water absorption of the back coat layer is 1 g/m2 or more.

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 for recording using ink, and more particularly, to a method of storing the ink-jet recording sheet in a state of being laminated or in contact with the printing surface before ink moisture evaporates after ink-jet recording. The present invention relates to an ink jet recording sheet having improved bleeding generated in the ink jet recording sheet.

[0002]

2. Description of the Related Art Generally, an ink recording portion of a recording sheet used for ink jet recording includes a so-called swellable ink recording layer mainly composed of a hydrophilic binder, and a void type ink having a void layer in the recording layer. It can be broadly divided into recording layers.

[0003] The swellable ink recording layer can obtain very high gloss and high maximum density after the ink solvent (water and high boiling point organic solvent) is completely evaporated. Slower than the type recording material, the evaporation of the ink solvent, especially the high boiling point organic solvent, was extremely slow in the high ink area, so the high boiling point organic solvent remained in the hydrophilic binder for a while after printing and the hydrophilic binder swelled. There are problems associated with prolonged exposure to wet conditions. Specifically, the printing surface cannot be strongly rubbed or paper cannot be overlapped for several hours after printing, and in some cases for several days.

On the other hand, the characteristic of the gap type ink recording layer is that it has a gap in the recording layer so that the ink absorption speed is high, and it is suitable for use in a recent high-speed ink jet printer. Further, after recording, the ink solvent is absorbed into the voids, so that even when printing is continuously output, the recording sheets are less likely to stick together. However, in the case of an inkjet recording sheet using a plastic or the like that does not absorb water as a support, the solvent contained in the aqueous inkjet ink stays for a long time without evaporating in the recording layer. Among them, there was a disadvantage that the boundary of the formed image was easily blurred. It has been found that the above problem becomes apparent particularly when printing is performed continuously at high speed.

On the other hand, when a paper support in which both sides of the paper are coated with a plastic material such as polyolefin is used, the above-mentioned problems can be recognized. However, in these recording materials, the polyolefin coating layer is not used. Since the thickness of the ink is very thin and the solvent such as water in the ink gradually penetrates into the support, the bleeding of the image during storage is smaller than that of the ink jet recording sheet using the plastic support. .

As described above, bleeding of an image when stored for a long period of time is a major drawback, particularly for an ink jet recording sheet using a plastic support, and an immediate improvement is required.

In addition, when the printer operates at a high speed, the drying of the ink becomes more and more difficult, and when the recording sheets printed next sequentially overlap, the ink of the sheet printed on the back surface adheres to the surface of another recording sheet. That is, so-called set-off is likely to occur, and particularly, high-density set-off is likely to occur in a portion having a high liquid amount. Particularly, in a recording sheet for OHP use using a film support, OH
When projecting at P, this set-off is projected, resulting in a great loss of image quality as an OHP.

To solve the above problem, a method of alternately storing sheets having solvent absorbency between ink-jet recording sheets after printing as interleaving paper has been taken.
There is also troublesome operation.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned problems, and has as its object to store ink-jet recording in a state of being laminated or contacted on a printing surface before ink moisture evaporates. An object of the present invention is to provide an ink jet recording sheet with improved bleeding generated when the recording is performed.

[0010]

The above object of the present invention has been attained by the following constitutions.

1. An ink jet recording sheet having a recording layer on one surface of a film support, and having a backcoat layer containing a water-swellable polymer hardened on a surface opposite to the recording layer via the support. An ink jet recording sheet, wherein the recording layer is a void layer containing a hardened hydrophilic polymer and fine particles, and the back coat layer has a water absorption of 1 g / m ² or more.

2. In an ink jet recording sheet having a recording layer on one surface of a film support and a back coat layer forming a void structure on a surface opposite to the recording layer via the support, the recording layer was hardened. An ink jet recording sheet comprising a void layer containing a hydrophilic polymer and fine particles, wherein the back coat layer has a water absorption of 1 g / m ² or more.

Hereinafter, the present invention will be described in detail. In the present invention, one of the features is that the water absorption of the back coat layer is 1 g / m ² or more, and preferably 1 g / m 2.
² or more and less than 8 g / m ² . When the water absorption of the back coat layer is less than 1 g / m ² , the effect of improving print bleeding when the output recording sheets are laminated and stored is hardly recognized, and when the water absorption is 8 g / m ² or more. If it exceeds, although the effect of improving bleeding is observed, a difference occurs in the moisture absorption balance with the recording layer coated on the opposite side with the support interposed therebetween, and as a result, the curl balance of the recording sheet collapses, which is preferable. Absent.

In the present invention, there is no particular limitation on the means for setting the water absorption of the back coat layer to the above-mentioned characteristics. For example, selection of the polymer compound to be used, setting of the type and amount of the curing agent, porosity Alternatively, it can be achieved by appropriately selecting a means such as a film thickness.

The water absorption of the back coat layer in the present invention is as follows:
It can be determined by the method described below. Only back coat layer on the film support to prepare a coated sample, after the sample of predetermined area, the mass was measured (W ₁₎ of the left sample 2 days at the 23 ° C. 20 RH% state of 23 ° C. Immersion in ion-exchanged water for 1 minute, then measuring the mass (W ₂ ) after wiping the surface of the water with filter paper, dividing the increased mass (W ₂ −W ₁ ) by the measured area, and absorbing water per unit area It is determined as an amount (g / m ² ).

One of the features of the present invention is that the void-type recording layer contains a hardened hydrophilic polymer and fine particles, and the fine particles used in the present invention are preferably inorganic fine particles. Examples of such inorganic fine particles include light calcium carbonate, heavy calcium carbonate,
Magnesium carbonate, kaolin, clay, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc hydroxide, zinc sulfide, zinc carbonate, hydrotalcite,
Aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica,
Examples include white inorganic pigments such as alumina, colloidal alumina, pseudoboehmite, aluminum hydroxide, lithopone, zeolite, and magnesium hydroxide. The inorganic fine particles can be used as they are as primary particles or in a state where secondary aggregated particles are formed.

In the present invention, silica or pseudo-boehmite is preferred from the viewpoint of forming fine voids, and silica, colloidal silica and pseudo-boehmite synthesized by a gas phase method having an average particle diameter of 100 nm or less are particularly preferred.

The method for producing silica fine particles is roughly classified into a dry method (gas phase method) and a wet method. Examples of the dry method include a method of gas phase hydrolysis of silicon halide at a high temperature (flame hydrolysis method), and There is known a method (arc method) in which silica sand and coke are heated and reduced in an electric furnace by an arc to be reduced and vaporized by air. As a wet method, a method is known in which active silica is generated by acid decomposition of a silicate, and then excessively polymerized to cause aggregation and precipitation. In the present invention, among the silica fine particles, silica synthesized by a gas phase method is most preferable.

The fine particle silica synthesized by the gas phase method is usually a silica powder having an average primary particle diameter of 5 to 500 nm obtained by burning silicon tetrachloride with hydrogen and oxygen at a high temperature. Those having an average primary particle diameter of 100 nm or less are preferred in terms of gloss. Examples of the commercially available fumed silica include various types of Aerosil manufactured by Nippon Aerosil Co., Ltd. and Tokuyama Corporation.

The average particle size of the inorganic fine particles can be determined by observing the cross section or surface of the particles or the void layer with an electron microscope.
The particle size of zero arbitrary particles is determined, and can be measured as a simple average value (number average). Here, each particle size is represented by a diameter assuming a circle equal to the projected area.

The ink jet recording sheet of the present invention has an ink recording layer containing the fine particles and having a void structure. When the fine particles are contained to form a void, the recording layer contains a hydrophilic polymer. This is necessary to form a stable film.

The hydrophilic polymer used in the void layer can be appropriately selected from known hydrophilic polymers and used, for example, polyvinyl alcohol and its derivatives, polyalkylene oxide, polyvinylpyrrolidone, polyacrylamide, and the like. Gelatin, hydroxyl ethyl cellulose, carboxymethyl cellulose,
Pullulan, casein, dextran and the like can be used, but the preferred hydrophilic polymer is polyvinyl alcohol.

The polyvinyl alcohol used in the present invention includes, in addition to general polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate, polyvinyl alcohol having a cation-modified terminal or anion-modified polyvinyl alcohol having an anionic group. Of modified polyvinyl alcohol. The polyvinyl alcohol obtained by hydrolyzing vinyl acetate preferably has an average degree of polymerization of 300 or more, and particularly preferably has an average degree of polymerization of 1000 to 500.
0 is preferably used. Saponification degree is 70-10
0% is preferable, and 80 to 99.5% is particularly preferable.

The hydrophilic polymer may be used in combination of two or more kinds. However, even in this case, it is preferable that polyvinyl alcohol or its derivative is contained at least 50% by mass or more. Examples of the polyvinyl alcohol derivative include cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol and nonion-modified polyvinyl alcohol. The cation-modified polyvinyl alcohol is obtained by saponifying a copolymer of an ethylenically unsaturated monomer having a cationic group and vinyl acetate. Examples of the ethylenically unsaturated monomer having a cationic group include trimethyl (2-acrylamide-
2,2-dimethylethyl) ammonium chloride, trimethyl (3-acrylamido-3,3-dimethylpropyl) ammonium chloride, N-vinylimidazole, N-vinyl-2-methylimidazole, N- (3-
Dimethylaminopropyl) methacrylamide, hydroxylethyltrimethylammonium chloride, trimethyl (methacrylamidopropyl) ammonium chloride, N- (1,1-dimethyl-3-dimethylaminopropyl) acrylamide and the like. The ratio of the cation-modified group-containing monomer in the cation-modified polyvinyl alcohol is 0.1 to 10 mol%, preferably 0.2 to 5 mol%, based on vinyl acetate. The polymerization degree of the cation-modified polyvinyl alcohol is usually 500 to 4000, preferably 1000 to 4000. The saponification degree of the vinyl acetate group is usually 60 to 100 mol%, preferably 70 to 99 mol%.
Mol%. Anion-modified polyvinyl alcohol is
For example, polyvinyl alcohol having an anionic group as described in JP-A-1-206088,
JP-A-61-237681 and JP-A-63-30797.
No. 9 discloses a copolymer of vinyl alcohol and a vinyl compound having a water-soluble group, and a modified polyvinyl alcohol having a water-soluble group described in JP-A-7-285265. No. Examples of the nonionic modified polyvinyl alcohol include, for example, polyvinyl alcohol derivatives described in JP-A-7-9758, in which a polyalkylene oxide group is added to a part of vinyl alcohol, and JP-A-8-2.
No. 5795, a block copolymer of a vinyl compound having a hydrophobic group and vinyl alcohol, and the like. The ratio of the fine particles to the hydrophilic polymer in the void layer of the ink jet recording sheet of the present invention is approximately 2 to 10 times by mass, preferably 3 to 8 times.

The addition of a hardening agent capable of crosslinking with the hydrophilic polymer to the void layer of the ink jet recording sheet of the present invention improves the film forming properties of the void layer and the water resistance of the film. Is preferred.

The hardener is generally a compound having a group capable of reacting with the hydrophilic polymer or a compound which promotes a reaction between different groups of the hydrophilic polymer. It is appropriately selected and used depending on the situation.

Specific examples of the hardener include epoxy hardeners (eg, diglycidyl ethyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-diglycidyl cyclohexane, N , N-diglycidyl-4-glycidyloxyaniline, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, etc., aldehyde hardeners (eg, formaldehyde, glyoxal, etc.), active halogen hardeners (eg, 2,4- Dichloro-4-hydroxy-1,3,5-s-triazine, etc.), active vinyl compounds (eg, 1,3,5-trisacryloyl-hexahydro-s-triazine, bisvinylsulfonyl methyl ether, etc.), boric acid and Its salt, borax, and aluminum Etc. The.

In the case where polyvinyl alcohol is used as a particularly preferred hydrophilic polymer, it is preferable to use at least one hardener selected from boric acid and salts thereof or an epoxy hardener. Most preferred is a hardener selected from boric acid and its salts.

In the present invention, boric acid or a salt thereof includes
Oxygen acid having a boron atom as a central atom and salts thereof, and specifically include orthoboric acid, diboric acid, metaboric acid, tetraboric acid, pentaboric acid, octanoic acid and salts thereof.

The amount of boric acid or a salt thereof cannot be specified unconditionally depending on the amount of the fine particles or the hydrophilic polymer in the coating solution, but is generally about 1 to 60% by mass, preferably 5 to 40% by mass relative to the hydrophilic polymer. %.

In addition to the boric acid-based curing agent, an epoxy-based curing agent, an aldehyde-based curing agent, an ethyleneimine-based curing agent, an isocyanate-based curing agent, an active halogen-based curing agent, and the like can be used in combination.

Various additives other than those described above can be added to the ink recording layer of the ink jet recording sheet of the present invention. For example, it is preferable that the void layer of the inkjet recording sheet of the invention contains a cationic polymer for the purpose of improving the water resistance and bleeding resistance of the image. As the cationic polymer used in the present invention,
For example, a cationic polymer having a primary to tertiary amino group and a quaternary ammonium base can be used,
A cationic polymer having a quaternary ammonium base is preferred because it has little discoloration or deterioration of light resistance over time and high fixability of the dye. Preferred cationic polymers are obtained as a homopolymer of the above-mentioned monomer having a quaternary ammonium base, a copolymer with other monomers, or a condensation polymer. Specific examples of cationic polymers include, for example, “Inkjet printer technology and materials”
268 (published by CMC Corporation, 1998).

In addition to the above, if necessary, for example, ultraviolet absorbers described in JP-A-57-74193, JP-A-57-87988 and JP-A-62-261476, and JP-A-57-74192 can be used. No. 57-87989, No. 60-72785, No. 61-14659.
No. 1, JP-A-1-95091 and 3-13
No. 376, etc., an anti-fading agent, various anionic, cationic or nonionic surfactants, JP-A-59-42993, JP-A-59-52689,
Fluorescent whitening agents, defoamers, lubricants such as diethylene glycol and glycerin, preservatives and thickeners described in JP-A-62-280069, JP-A-61-242871 and JP-A-4-219266. And various known additives such as an antistatic agent.

Further, a matting agent can be used if necessary, and the matting agent may be fine particles of organic or inorganic materials, for example, titanium oxide, silica, glass powder, barium sulfate, polystyrene resin, polymethyl methacrylate resin. , Polycarbonate resin and polyacrylate copolymer resin. The matting agent may be monodispersed or polydispersed. The particle size is 0.
It is preferably from 5 to 20 μm, particularly preferably from 1 to 15 μm.

In applying the recording layer of the present invention to a film support, the support may be subjected to corona discharge treatment or provided with an undercoat layer for the purpose of increasing the adhesive strength between the surface and the coating layer. Is preferred. As the undercoat layer, a layer in which a hydrophilic polymer such as gelatin or polyvinyl alcohol is used in combination with a hardener as necessary can be provided.
The preferred thickness of the undercoat layer is in the range of 0.01 to 1 μm.

The ink recording layer can be applied by a roll coating method, a rod bar coating method, an air knife coating method, a spray coating method, a curtain coating method, or an extrusion method using a hopper described in US Pat. No. 2,681,294. The lug coat method is preferably used.

One of the features of the invention according to claim 1 is that the back coat layer contains a hardened water-swellable polymer.

As the water-swellable polymer used in the present invention, crosslinked gelatin is preferably used, but other crosslinked hydrophilic polymers can also be used. For example, polyvinyl alcohol, gelatin derivatives, graft polymers of gelatin and other polymers, albumin,
Proteins such as casein, hydroxyethyl cellulose, carboxymethyl cellulose, cellulose derivatives such as cellulose sulfate, sodium alginate, cellulose sulfate, dextrin, dextran, saccharide derivatives such as dextran sulfate, poly-N-vinylpyrrolidone, polyacrylic acid, A crosslinked product of a single kind of polymethacrylic acid, polyacrylamide, polyvinylimidazole, polyvinylpyrazole, or a variety of synthetic hydrophilic polymers such as copolymers can be used. As gelatin, acid-treated gelatin may be used in addition to lime-treated gelatin, and a hydrolyzate of gelatin and an enzyme-decomposed product of gelatin can also be used. These water-swellable polymers may be used alone or in combination.

These water-swellable polymers must be hardened with a hardener, and the degree of hardening is determined by the swelling ratio [100 × water absorption of backcoat layer (g / m ² ) / Amount (g / m ² ) of water-swellable polymer] is preferably about 50 to 300%. When the swelling ratio is less than 50%, there is almost no effect of improving bleeding generated when another ink jet recording sheet or another object is left in contact with the printing surface. On the other hand, if the swelling ratio exceeds 300%, the curl balance may be deteriorated, or the back coat surface and the printing surface may stick together when left over, and this effect is hardly exhibited.

In the present invention, the hardening agent used for the water-swellable polymer is not particularly limited as long as it can impart swelling properties. For example, aldehydes such as formaldehyde, glyoxal, glutaraldehyde, succinaldehyde, mucochloric acid, Mucohalogenic acids such as mucobromoic acid; N-methylols such as dimethylolurea;
Examples include dichloro-s-triazines, activated ethylenes having a vinylsulfone group or an acrylamide group, ethyleneimines, epoxies, and carbodiimides. In order to obtain crosslinked gelatin, dichloro-s-triazines, vinylsulfone-type active ethylenes, and carbodiimides are preferably used.

Further, in addition to the water-swellable polymer, a resin emulsion, a matting agent and a surfactant can be added to the back coat layer in an appropriate combination.

As matting agents, white pigments such as silica, titanium oxide, barium sulfate, talc, kaolin clay, calcium carbonate, etc. polyethylene, polypropylene, polystyrene, polymethyl acrylate, polyethyl ethyl, polymethyl methacrylate, polymethacrylic acid Ethyl, polyvinyl acetate, ethylene vinyl acetate copolymer resin,
Fine particle polymers such as epoxy resin, urea-formalin resin, and melamine-formalin resin are exemplified.

The thickness of the back coat layer is 0.5 to 10 μm.
m is good, and preferably 1 to 5 μm in consideration of the curl balance of the recording sheet.

One of the features of the invention according to claim 2 is that the back coat layer has a void structure, and the void layer formed in the back coat layer is mainly composed of inorganic fine particles and hydrophilic particles. Examples of the inorganic fine particles made of a polymer include the same fine particles as the fine particles in the void-type recording layer.

The hydrophilic polymer used in the void-type back coat layer may be the same as the hydrophilic polymer described in the void-type recording layer. A preferred hydrophilic polymer is polyvinyl alcohol.

The ratio of the fine particles to the hydrophilic polymer in the back coat layer of the present invention is about 2 to 10 times, preferably 3 to 8 times by mass, as in the case of the gap type recording layer. The thickness of the back coat layer according to claim 2 is generally 1.5 to 15 μm, preferably 2 to 10 μm.
μm.

When the above-mentioned void-type back coat layer contains polyvinyl alcohol as a hydrophilic polymer, the film-forming properties of the film are improved and the water resistance and strength of the film are improved as in the case of the void-type recording layer. In order to increase the hardness, the same hardener as described above is contained, and a boric acid-based hardener is particularly preferable. Further, in addition to the boric acid-based curing agent, an epoxy-based curing agent,
An aldehyde-based curing agent, an ethyleneimine-based curing agent, an isocyanate-based curing agent, an active halogen-based curing agent, and the like can be used in combination. Further, in addition to the above, various additives described in the recording layer can be used as needed.

In applying the back coat layer to the support, it is preferable to subject the support to a corona discharge treatment or to provide an undercoat layer for the purpose of increasing the adhesive strength between the surface and the coating layer. As the undercoat layer, a layer in which a hydrophilic polymer such as gelatin or polyvinyl alcohol is used in combination with a curing agent as necessary is provided. The preferred thickness of the undercoat layer is in the range of 0.01 to 1 μm. The thickness of the back coat layer is preferably in the range of 1 μm to 10 μm.

The swelling type or void type back coat layer is applied to the support by a known coating method such as a slide hopper method, a curtain method, an extrusion method, an air knife method, a roll method, a rod method, and a wire bar method. be able to.

One of the features of the present invention is to use a film support. The film support used in the present invention may be transparent or opaque, and various resin films can be used. Polyolefin films (polyethylene, polypropylene, etc.) and polyester films (polyethylene terephthalate, polyethylene naphthalene) Phthalate), polyvinyl chloride, cellulose triacetate and the like can be used, and a polyester film is preferable. The polyester film (hereinafter, referred to as polyester) is not particularly limited, but is preferably a film-forming polyester having a dicarboxylic acid component and a diol component as main components. The main components of the dicarboxylic acid component include terephthalic acid, isophthalic acid, phthalic acid, 2,6-
Naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenyletherdicarboxylic acid, diphenylethanedicarboxylic acid,
Examples thereof include cyclohexanedicarboxylic acid, diphenyldicarboxylic acid, diphenylthioetherdicarboxylic acid, diphenylketonedicarboxylic acid, and phenylindanedicarboxylic acid. As the diol component, ethylene glycol, propylene glycol, tetramethylene glycol, cyclohexane dimethanol,
2,2-bis (4-hydroxyphenyl) propane,
Examples thereof include 2,2-bis (4-hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, bisphenol full orange hydroxyethyl ether, diethylene glycol, neopentyl glycol, hydroquinone, and cyclohexanediol. In terms of transparency, mechanical strength, dimensional stability, etc. among polyesters containing these as main constituents,
As the dicarboxylic acid component, terephthalic acid or 2,6-naphthalenedicarboxylic acid is preferable, and as the diol component, a polyester mainly containing ethylene glycol or 1,4-cyclohexanedimethanol is preferable. Among them, polyesters mainly composed of polyethylene terephthalate or polyethylene naphthalate, copolymerized polyesters composed of terephthalic acid, 2,6-naphthalenedicarboxylic acid and ethylene glycol, and mixtures of two or more of these polyesters are mainly used. Polyester as a constituent component is preferred.

The thickness of the film support used in the present invention is preferably 50 to 300 μm, particularly preferably 80 to 250 μm. Further, the film support of the present invention may be a laminate of two sheets, and in this case, the types may be the same or different.

The film support of the present invention may contain a white pigment. The amount of the white pigment varies widely depending on the particle size and type of the white pigment to be used. % By mass, preferably 5 to 30% by mass. Examples of white pigments that can be used include, for example,
Titanium oxide, barium sulfate, zinc oxide, calcium carbide and the like can be mentioned, but titanium oxide is particularly preferred.

[0053]

The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples.

Example 1 << Preparation of Recording Sheet 1 >> A recording sheet 1 for ink jet was prepared according to the method described below.

(Coating of Backcoat Layer) On one surface of a white polyethylene terephthalate (100 μm thick) film support, a coating solution of a backcoat layer having the following composition was prepared, filtered, and dried. Coating was performed to a thickness of 2.7 μm to form a back coat layer.

[Backcoat layer coating solution: B-1] Acid-treated gelatin 43 parts by mass Monodisperse matting agent composed of methyl methacrylate latex (particle size: 5 μm) 1.2 parts by mass Fluorinated anionic surfactant F-1 0.3 parts by mass Hardener A 4.5 parts by mass

[0057]

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(Coating of Recording Layer) On the surface opposite to the back coat layer of the film support having the back coat layer coated thereon, each layer having the following constitution was coated to form a recording layer.

[Preparation of Titanium Oxide Dispersion 1] 20 kg of titanium oxide having an average particle size of about 0.25 μm (manufactured by Ishihara Sangyo: W
-10) was added to 150 g of sodium tripolyphosphate having a pH of 7.5 and polyvinyl alcohol (Kuraray Co., Ltd .: P
VA235) 500 g, 15 of the cationic polymer P-1
0 g and the antifoaming agent SN381 manufactured by Sannobuco
The solution was added to 90 L of an aqueous solution containing 0 g and dispersed with a high-pressure homogenizer (manufactured by Sanwa Kogyo Co., Ltd.).

[0060]

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[Preparation of Silica Dispersion 1] 125 kg of fumed silica (QS20, manufactured by Tokuyama Corporation) having an average primary particle size of about 0.014 μm was added to a jet stream inductor mixer manufactured by Mitamura Riken Kogyo Co., Ltd. Using TDS, suction dispersion was performed at room temperature in 600 L of pure water whose pH was adjusted to 2.5 with nitric acid, and then the total amount was adjusted to 660 L with pure water to prepare a silica dispersion liquid 1.

[Preparation of silica dispersion 2] 1.05 kg of the cationic polymer P-1, 4.2 L of ethanol,
An aqueous solution containing 1.5 L of n-propanol (pH =
2.3) In 15 L, add the silica dispersion 1 prepared above to 6
6.0 L with stirring and then 240 g of boric acid
And 7.0 g of an aqueous solution containing 220 g of borax,
1 g of the antifoaming agent SN381 was added. This mixed solution was dispersed with a high-pressure homogenizer manufactured by Sanwa Kogyo Co., Ltd., and the whole amount was adjusted to 90 L with pure water to prepare a silica dispersion liquid 2.

[Preparation of Image Stabilizer Dispersion 1] 2400 g of image stabilizer SA-1 was added to diisodecyl phthalate 900
g of ethyl acetate and 2.5 L of ethyl acetate, and heat-dissolve this in 1500 g of acid-treated gelatin, cationic polymer (P-1) 1
000 g, saponin was added to and mixed with 12 L of an aqueous solution containing 2 L of a 50% aqueous solution, and emulsified and dispersed using a high-pressure homogenizer manufactured by Sanwa Kogyo Co., Ltd., and ethyl acetate was removed under reduced pressure.

[0064]

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[Preparation of Coating Solutions for Each Recording Layer] Coating solutions for the first, second, and third recording layers were prepared according to the following method.

<Preparation of First Layer Coating Solution> The following additives were sequentially mixed with 560 ml of the prepared silica dispersion 2 at 40 ° C. to prepare a first layer coating solution.

A 10% aqueous solution of polyvinyl alcohol (Kuraray Industries, Ltd .: PVA203) 0.6 ml A 5% aqueous solution of polyvinyl alcohol (Kuraray Industries, Ltd .: PVA235) 150 ml 5 of polyvinyl alcohol (Kuraray Industries, Ltd .: PVA245) % Aqueous solution 100 ml Image stabilizer dispersion liquid 28 ml Titanium oxide dispersion liquid 1 30 ml Latex emulsion AE-803 manufactured by Daiichi Kogyo Co., Ltd. 21 ml The total amount was made up to 1000 ml with pure water.

<Preparation of Second Layer Coating Solution> The following additives were sequentially mixed with 630 ml of the prepared silica dispersion 2 at 40 ° C. to prepare a second layer coating solution.

A 10% aqueous solution of polyvinyl alcohol (Kuraray Industries, Ltd .: PVA203) 0.6 ml A 5% aqueous solution of polyvinyl alcohol (Kuraray Industries, Ltd .: PVA235) 150 ml 5 of polyvinyl alcohol (Kuraray Industries, Ltd .: PVA245) % Aqueous solution 100 ml Image stabilizer dispersion liquid 160 ml The total amount was made up to 1000 ml with pure water.

<Preparation of Third Layer Coating Solution> The following additives were sequentially mixed with 640 ml of the prepared silica dispersion 2 at 40 ° C. to prepare a third layer coating solution.

0.6% of 10% aqueous solution of polyvinyl alcohol (Kuraray Industries, Ltd .: PVA203) 5 ml of 5% aqueous solution of polyvinyl alcohol (Kuraray Industries, Ltd .: PVA235) 150 ml of polyvinyl alcohol (Kuraray Industries, Ltd .: PVA245) % Aqueous solution 100 ml Silicon dispersion (BY-22-839, manufactured by Dow Corning Silicone Co., Ltd.) 3.5 ml 50% aqueous solution of saponin 4 ml 5% aqueous solution of fluorinated nonionic surfactant 2 ml Complete water is made up to 1000 ml with pure water Was.

The above-prepared coating solutions for the respective layers were applied to the first layer and the second layer.
The layer was filtered with a two-stage configuration of TCP10 manufactured by Toyo Roshi Kaisha, Ltd., and the third layer was filtered with a two-stage configuration of TCP30 manufactured by Toyo Filter Paper Co., Ltd.

[Coating of Recording Layer] Using the coating solutions prepared above, the first layer was 40 μm and the second layer was 1 μm from the support side.
10 μm, so that the third layer has a wet thickness of 30 μm,
On the surface of the film support having the back coat layer coated thereon opposite to the back coat layer, simultaneous coating was carried out by the method described below to prepare recording sheet-1.

Coating was performed simultaneously at 40 ° C. with a three-layer curtain coater, immediately after coating, cooled in a cooling zone maintained at 8 ° C. for 20 seconds, and then blown with a wind of 20 to 30 ° C. for 60 seconds. 60 seconds at 45 ° C, 60 seconds at 50 ° C
It dried sequentially for seconds. The film temperature in the constant rate drying region was 8 to 25 ° C., and after gradually increasing the film temperature in the decreasing rate drying region, the humidity was adjusted at 23 ° C. and a relative humidity of 40 to 60% to obtain a recording sheet-1. I got

Next, on recording sheet-1, 2: 8 of an isocyanate-based crosslinking agent dissolved in ethyl acetate (Coronate 3041 manufactured by Nippon Polyurethane Industry Co., Ltd.) and Sumidur N3300 manufactured by Sumitomo Bayer Urethane Co., Ltd.
(Mass ratio) isocyanate is 1.2 g / m ²
Was overcoated.

The dry film thickness of each layer in the recording sheet-1 produced as described above was confirmed from the micrograph of the section, where the first layer was 8 μm, the second layer was 23 μm, and the third layer was 6 μm.

<< Preparation of Recording Sheets 2 to 13 >> (Preparation of Recording Sheet-2) A recording sheet was prepared in the same manner as in the preparation of Recording Sheet-1, except that the thickness of the back coat layer was changed to 1.3 μm. -2 was produced.

(Preparation of Recording Sheet-3) Recording Sheet-3 was prepared in the same manner as in the preparation of Recording Sheet-1, except that the amount of hardener A in the back coat layer was changed to 2.3 parts by mass. Was prepared.

(Preparation of Recording Sheet-4) In the preparation of the recording sheet-3, the thickness of the back coat layer was set to 1.3 μm.
Recording sheet-4 was produced in the same manner except that m was changed to m.

(Preparation of Recording Sheet-5) Recording Sheet-5 was prepared in the same manner as in the preparation of Recording Sheet-1, except that the amount of hardener A in the back coat layer was changed to 1.4 parts by mass. Was prepared.

(Preparation of Recording Sheet-6) In the preparation of the recording sheet-5, the thickness of the back coat layer was set to 1.3 μm.
Recording sheet-6 was produced in the same manner except that m was changed to m.

(Preparation of Recording Sheet-7) In the same manner as in the preparation of the recording sheet-1, except that the addition amount of the hardener A in the back coat layer was changed to 1.0 part by mass, the recording sheet-7 was prepared in the same manner. Was prepared.

(Preparation of Recording Sheet-8) In the preparation of the recording sheet-7, the thickness of the back coat layer was set to 1.3 μm.
Recording sheet-8 was produced in the same manner except that m was changed to m.

(Preparation of Recording Sheet-9) A recording sheet-9 was prepared in the same manner as in the preparation of the recording sheet-1, except that the hardener A of the back coat layer was omitted.

(Preparation of Recording Sheet-10) A recording sheet-10 was prepared in the same manner as in the preparation of the recording sheet-1, except that the back coat layer was omitted.

(Preparation of Recording Sheet-11) In the preparation of the recording sheet-1, the coating liquid for the back coat layer was applied to B-1.
Was changed to B-2 below, and a recording sheet 11 was produced in the same manner. The back coat layer was applied so that the dry film thickness was 2.7 μm.

<Coating solution for back coat layer: B-2> Polyvinyl alcohol (manufactured by Kuraray Industries Co., Ltd .: PVA235) 40 parts by mass Methylol melamine 10 parts by mass Monodisperse matting agent composed of methyl methacrylate latex (particle size: 5 μm) 2 parts by mass Anionic surfactant 0.3 parts by mass Boric acid 4.8 parts by mass Borax 4.4 parts by mass (Preparation of recording sheet -12) Recording sheet-12 was produced in the same manner except that the thickness was changed to 5.0 μm.

(Preparation of Recording Sheet-13) In the recording sheet-11, the dry film thickness of the back coat layer was 7.8.
A recording sheet 13 was produced in the same manner except that the thickness was changed to μm.

<< Evaluation of Image of Each Recording Sheet >> (Evaluation of Water Absorption of Back Coat Layer) A sample piece (8 cm × 10 cm) was prepared by separately applying only the back coat layer in each recording sheet except for the recording sheet-10. After measuring the mass (W ₁ ) of the sample left for 2 days at 23 ° C. and 20 RH%, the sample was immersed in ion-exchanged water at 23 ° C. for 1 minute, and then the surface was lightly suppressed with filter paper to wipe off the surface moisture. The mass (W ₂ ) was measured and the increased mass (W ₂ −
W ₁ ) is divided by the measured area to obtain the amount of water absorption per unit area (g)
/ M ² ) was measured.

(Evaluation of Print Bleeding During Storage) For the recording sheets-1 to 13 prepared above, an ink jet printer PM800C manufactured by Seiko Epson Corporation was used.
After continuously printing and outputting black ink having a width of about 250 μm on solid printing of magenta ink, five sheets are superimposed so that the printing surface and the back surface are in direct contact, and the temperature is 40 ° C. and the relative humidity is 8
Stored under 0% atmosphere for 2 days.

The line width of the black ink on the recording sheet after the preservation treatment was measured with a microdensitometer, and the increase rate of the line width after the preservation relative to the line width before the preservation (ink bleeding) was measured. If the rate of increase was 1.5 or less, it was determined that the level was practically acceptable.

(Evaluation of curl) After each recording sheet was cut into A4 size paper, it was stored for one day in an atmosphere of 23 ° C. and 20% RH, and the average height of lifting at four corners was obtained. And The + symbol indicates a so-called concave shape in which the four corners are higher than the center when the printing surface is facing upward, and the-symbol indicates the opposite convex shape.

(Evaluation of sticking) In the sample of the print bleed evaluation described above, when the recording sheet laminated after the preservation treatment was peeled off, whether or not there was a sticking mark on the back side of the printed surface was visually evaluated according to the following criteria. .

A: No sticking mark on the back side is observed on the printed surface after peeling. B: There is a slight sticking mark on the printed surface after peeling, but there is no practical problem. C: On the printed surface after peeling. Clearly sticky marks are scattered and there is some problem in practical use. D: When sticking marks occur over almost the entire surface after peeling, it does not endure practical use. The results obtained above are shown in Table 1.

[0095]

[Table 1]

As is evident from Table 1, a void layer comprising a hardened hydrophilic polymer and fine particles was provided on the printing surface of the film support, and the back coat layer was formed of a hardened swellable polymer and had a water absorption. Sheet having a value of 1 g / m ² or more
Nos. 1 to 8 show that print bleeding during image storage is small. Also, among these, the recording paper having a swelling degree of 300% or less is excellent in curl and sticking, and it is understood that it is a particularly preferable recording paper.

Example 2 << Preparation of Recording Sheet-14 to 16 >> (Preparation of Recording Sheet-14) In the preparation of the recording sheet-1 described in Example 1, the backcoat layer was replaced with the recording sheet-
Change to the third layer liquid used on the recording layer side of No. 1 and dry film thickness is 7
Recording sheet-14 was prepared in the same manner except that the coating was performed so as to have a thickness of μm.

(Preparation of Recording Sheet-15) In the recording sheet-14, the dry film thickness of the back coat layer was 3 μm.
In the same manner except that the recording sheet 15 was changed, a recording sheet 15 was produced.

(Preparation of Recording Sheet-16) In the recording sheet-14, the dry film thickness of the back coat layer was 1 μm.
The recording sheet 16 was produced in the same manner except that the recording sheet 16 was changed.

The recording sheets -14 to 16 prepared above were evaluated in the same manner as in Example 1 for water absorption of the back coat layer, print bleeding after storage, curl, and sticking. The results are shown in Table 2.

[0101]

[Table 2]

As is apparent from Table 2, the recording layer on the film support according to the present invention has a hardened hydrophilic polymer and a void layer composed of fine particles, and has a water absorption of 1 g / m ^2.
The ink jet recording sheets -14 and 15 provided with the above-mentioned void-type back coat layer have significantly improved print bleeding during image storage, which is a major problem when a recording sheet having a film support is used, and have curl characteristics. Was also found to be good.

[0103]

The ink jet recording sheet of the present invention is
It has an excellent effect of greatly improving the bleeding that occurs when another ink jet recording sheet or another object is left in contact with the printing surface before the moisture of the ink after ink jet recording evaporates.

Claims (2)

[Claims] 1. An ink jet apparatus comprising: a film support having a recording layer on one surface thereof; and a backcoat layer containing a water-swellable polymer hardened on a surface opposite to the recording layer via the support. An ink jet recording sheet, wherein the recording layer is a void layer containing a hardened hydrophilic polymer and fine particles, and the back coat layer has a water absorption of 1 g / m ² or more. 2. An ink jet recording sheet having a recording layer on one surface of a film support and a back coat layer having a void structure on a surface opposite to the recording layer with the support interposed therebetween. An ink jet recording sheet, which is a void layer containing a hardened hydrophilic polymer and fine particles, and wherein the water absorption of the back coat layer is 1 g / m ² or more.