JP2000127611A - Ink image receiving sheet and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a recorded image of high water resistance by giving high ink absorption properties and ink fixing properties to an ink image receiving sheet to be used in an ink-jet system. SOLUTION: An ink image receiving sheet is formed by treating a nonwoven fabric with a hydrophilic polymer, a crosslinking agent, and as required powder and granular material. A polymer having at least hydroxyl groups such as a modified polyvinyl alcohol (a cellulose derivative, a vinyl polymer, a polysulfone polymer, and others) can be used as the hydrophilic polymer, and a polyvalent carboxylic acid or its acid anhydride can be used as the crosslinking agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ink receiving sheet and a method for producing the same. More specifically, the present invention relates to an ink receiving sheet having excellent ink absorbency, ink fixing property, printability, water resistance and durability of a recorded image in an ink jet recording system, and a method for producing the same.

[0002]

2. Description of the Related Art Ink-jet recording systems are easy to achieve full color, have low noise, and are excellent in printing quality. In addition, inkjet printers are widely used as printing / output devices such as recording devices for computers, word processors, and copiers because they are inexpensive and easy to operate at high speed. As an ink component for ink jet recording, a water-based ink is mainly used in terms of safety and recording suitability, and recording is performed by flying small ink droplets from nozzles toward a recording sheet. If the ink absorption of the recording sheet used is low, the ink may scatter around the ink droplets that have been ejected, or the ink may remain on the surface of the recording sheet for a long time after the end of recording, causing contact with parts of the device. ,
By contacting the handler and superimposing the recording sheets,
The recorded part becomes dirty. In the high-density image area, a large amount of supplied ink is mixed without absorption and flows out, resulting in an unclear image. For this reason, the recording sheet is required to quickly absorb the ink and to have high fixability.

JP-B-63-56876 discloses an ink jet recording sheet provided with a porous resin layer having pores in a continuous film. In addition, Japanese Unexamined Patent Publication No.
Japanese Patent No. 22983 discloses an inkjet recording sheet made of a hydrophilic polymer sheet having a large number of micropores. However, in these sheets, it is considered that the water resistance is considerably improved by providing the porous resin layer.However, when the ink absorbing layer is formed only of the porous resin having pores, the printing result and the water resistance are improved. Has limitations.

A nonwoven fabric is also known as a porous substrate, and has excellent properties such as bulkiness, softness, tear resistance and wet strength that are not found in paper. It is used for creating indoor and outdoor advertising materials such as curtains, banners, and signboards, interior decorations, and reproductions. However, even when used as an ink-jet recording sheet, high-density printing cannot be performed and only low-quality images can be obtained due to the low absorbency of the ink-jet water-based ink.
Further, the obtained image has poor water resistance, and if water is applied to the printed portion, the image is blurred and deteriorated. In order to improve these disadvantages, JP-A-7-68922 and JP-A-8-1
Japanese Patent No. 87933 discloses a recording sheet in which an ink receiving layer made of an inorganic pigment and a binder resin is provided on a nonwoven fabric. In these sheets, ink absorption,
Although image density and sharpness are improved, water resistance is low,
The fibers are fixed to each other to give a very hard texture, and the soft feeling is lost. JP-A-7-266690 discloses a recording sheet in which an adhesive layer and a coating layer composed of an inorganic powder and a cationic polymer resin are sequentially laminated on a base cloth. By providing the adhesive layer, the penetration of the ink into the base fabric can be shielded, so that the sharpness of the image is improved, but the water resistance is low, the fibers are fixed to each other, resulting in a very hard feeling, and the soft feeling is lost. I will be. JP 8
JP-311785 describes an inkjet recording fabric having a boehmite porous layer on the fiber surface of the fabric and having been subjected to a kneading and loosening treatment. Although the softening is achieved by the kneading and unraveling process, the cost increases due to the additional steps. Also, since the binder is used in a relatively small amount of 50% by weight or less of boehmite, the ink absorbency is improved, but the coating film becomes brittle, the weather resistance and water resistance are insufficient, and the coating is performed during the rubbing treatment. There is a risk that the film will be missing. JP-A-10-29370 discloses an ink absorbing layer in which a binder is mixed with 50 to 200 parts by weight with respect to 100 parts by weight of an inorganic filler on a fiber base material.
A recording sheet in which an image shielding layer is laminated on the back surface via an adhesive layer is disclosed. In the ink absorbing layer, by increasing the blending amount of the binder with respect to the inorganic filler as compared with the conventional case, the strength of the coating film is improved, but the ink absorbency is reduced and the feeling is deteriorated.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to form a clear image by suppressing ink bleeding.
Moreover, an object of the present invention is to provide an ink image-receiving sheet having a good texture and a method of manufacturing the same.

Another object of the present invention is to provide a non-woven fabric,
An object of the present invention is to provide an ink image receiving sheet which is excellent in printability and excellent in ink absorbability and ink fixability, and a method for producing the same.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, have found that a treatment liquid composed of a hydrophilic polymer, a crosslinking agent and, if necessary, a granular material is used. It has been found that the treatment of the nonwoven fabric can significantly improve the printability, ink absorbability and ink fixability, and furthermore, the durability of the image, and completed the present invention.

That is, the ink image-receiving sheet of the present invention comprises:
At least one surface is composed of a nonwoven fabric treated with a hydrophilic polymer, a crosslinking agent, and, if necessary, a powder. The hydrophilic polymer may be a polymer having at least a hydroxyl group. As the crosslinking agent, a polyvalent carboxylic acid or an acid anhydride thereof can be used.

The ink-receiving sheet of the present invention can be produced by treating a nonwoven fabric with a hydrophilic polymer, a crosslinking agent and, if necessary, a powder.

[0010] In the present specification, the term "hydrophilic polymer" means a hydrophilic (water-affinity, water-dispersible) polymer or a water-insoluble water-absorbing polymer.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The ink receiving sheet of the present invention comprises a nonwoven fabric treated with a hydrophilic polymer, a crosslinking agent and, if necessary, a powder. Such an ink image receiving sheet is useful as an ink image receiving sheet for inkjet recording in which a recorded image is formed by flying ink droplets.

[Nonwoven Fabric] In the ink image-receiving sheet of the present invention, the nonwoven fabric has the advantage that it quickly absorbs the aqueous ink jetted by the ink jet, so that it can be apparently dried quickly on the sheet surface.

The type (material type) of the non-woven fabric is not particularly limited as long as the absorbability of the aqueous ink is not impaired. For example, natural fibers (cotton, hemp, silk, etc.), regenerated fibers (rayon, etc.), Semi-synthetic fibers (such as acetate) and synthetic fibers (such as nylon fiber, polyester fiber, acrylic fiber, and polyolefin fiber (such as polypropylene fiber)) can be used alone or in combination. The fiber may be a composite fiber having a sheath or a core structure. These fibers may be subjected to a surface treatment (for example, a hydrophilic treatment). The average fiber diameter is, for example, 0.01 to 10
It can be selected from the range of 0 μm, preferably about 0.1 to 50 μm.

The basis weight of the nonwoven fabric can be selected according to the ink absorbency, for example, 50 g / m ² or more, preferably 100 g / m ² or more.
g / m ² or more. The thickness of the nonwoven fabric can be appropriately selected depending on the application, for example, 50 μm to 2 mm,
Preferably 100 μm to 1 mm (for example, 100 to 500
μm), and more preferably about 100 to 300 μm. The fiber density of the nonwoven fabric (a value obtained by dividing the basis weight of the nonwoven fabric by the thickness of the nonwoven fabric) is 100 to 5000 kg / m ³ , preferably about 500 to 2000 kg / m ³ . Further, the air permeability of the nonwoven fabric is 0.1 to 100 cm ³ / cm ² · sec,
Preferably, it is about 0.1 to 50 cm ³ / cm ² · sec.

The ink receiving sheet of the present invention may be composed of at least a nonwoven fabric, and the nonwoven fabric may be laminated on at least one surface of a support. [Hydrophilic polymer] As the hydrophilic polymer, various hydrophilic polymers, for example, natural polymers or derivatives thereof (for example,
Starch, corn starch, alginic acid or a salt thereof (such as a sodium salt), gum arabic, gelatin, casein, dextrin, etc., a cellulose derivative (for example,
Methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, carboxymethylcellulose, cellulose sulfate, cyanoethylcellulose, etc., polyalkylene oxides (eg, polyethylene oxide, ethylene oxide-propylene oxide copolymer, etc.), vinyl alcohol polymers (eg, , Polyvinyl alcohol, modified polyvinyl alcohol (ethylene-vinyl alcohol copolymer, etc.), acrylic polymer (hydroxy-containing (meth) such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate)
Copolymer containing acrylate, (meth) acrylic acid-polyvinyl alcohol copolymer), ethylene-based polymer (ethylene-maleic anhydride copolymer, etc.), vinyl acetate-based copolymer (vinyl acetate-methyl acrylate copolymer) Polymer, etc.), a polymer having a carboxyl group or a sulfonic acid group or a salt thereof [acrylic polymer (poly (meth) acrylic acid or a salt thereof (an alkali metal salt such as ammonium or sodium)), methyl methacrylate- (meth) ) Acrylic acid copolymers, acrylic acid-polyvinyl alcohol copolymers, etc.), vinyl ether polymers (polyvinyl alkyl ethers such as polyvinyl methyl ether and polyvinyl isobutyl ether, methyl vinyl ether-maleic anhydride copolymers, etc.), styrene-based polymers Polymer (styrene-
Maleic anhydride copolymer, styrene- (meth) acrylic acid copolymer, sodium polystyrenesulfonate, etc.), sodium polyvinylsulfonate, etc.], nitrogen-containing polymer (or cationic polymer) or a salt thereof (polyvinylbenzyltrimethylammonium) Quaternary ammonium salts such as chloride and polydiallyldimethylammonium chloride, polydimethylaminoethyl (meth) acrylate hydrochloride, polyvinylpyridine, polyvinylimidazole, polyethyleneimine, polyamidepolyamine, polyacrylamide, polyvinylpyrrolidone, etc.)
And the like. In addition, the hydrophilicity having at least one functional group selected from (1) a polyoxyalkylene unit, (2) an acetoacetyl group, (3) a carboxyl group, (4) an acid anhydride group, and (5) an amino group. Molecules can also be used.

(1) Examples of the hydrophilic polymer having a polyoxyalkylene unit include vinyl ester polymers as described above (eg, a polyoxyalkylene-vinyl acetate copolymer having a hydrophilic group such as an ether group). Can be used.

(2) The acetoacetyl group-modified hydrophilic polymer includes an acetoacetyl group-containing hydrophilic polymer formed by a reaction between a hydroxyl group-containing hydrophilic polymer and acetoacetate, for example, an acetoacetyl group-modified hydrophilic polymer. Vinyl acetate copolymer (acetoacetyl group-containing polyvinyl alcohol, acetoacetyl group-containing cellulose derivative, etc.)
Is included. The acetoacetyl group-modified vinyl acetate copolymer can be obtained, for example, from Nippon Synthetic Chemical Industry Co., Ltd.

(3) Carboxyl group-modified hydrophilic polymer includes (3a) carboxyl group-modified polyvinyl alcohol,
For example, vinyl esters (vinyl acetate, vinyl propionate, vinyl formate, etc.) and carboxyl group-containing unsaturated monomers (monocarboxylic acids such as (meth) acrylic acid), dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid; These acid anhydrides or monoalkyl esters, etc.)
And partially saponified copolymers, for example, styrene-
(Meth) acrylic acid copolymer, (meth) acrylic acid ester- (meth) acrylic acid copolymer (eg, methyl methacrylate- (meth) acrylic acid copolymer), vinyl acetate-
(3) saponified compounds such as (meth) acrylic acid copolymer
b) carboxyl group-containing polysaccharides such as carboxy C
_1-4 alkyl cellulose, carboxymethyl dextran, alginic acid and the like.

(4) Acid anhydride group-containing hydrophilic polymers include:
Alkyl vinyl ether-maleic anhydride copolymer (such as methyl vinyl ether-maleic anhydride copolymer),
Ethylene-maleic anhydride copolymer, vinyl acetate-maleic anhydride copolymer, styrene-maleic anhydride copolymer, (meth) acrylate-maleic anhydride copolymer (methyl methacrylate-maleic anhydride copolymer) And the like).

(5) Examples of the amino group-containing hydrophilic polymer include polyamide-polyamine, polyvinylamine and poly (N-
Vinyl formamide), amino group-containing polysaccharides (aminodextran, chitosan, etc.). These hydrophilic polymers can be used alone or in combination of two or more.

Preferred hydrophilic polymers include hydrophilic polymers having at least a hydroxyl group, for example, cellulose derivatives (particularly, hydroxyethyl cellulose, etc.),
It includes a vinyl alcohol polymer (polyvinyl alcohol, modified polyvinyl alcohol, etc.), an acrylic polymer and the like, and particularly preferably a polyvinyl alcohol polymer (polyvinyl alcohol, modified polyvinyl alcohol).

The degree of saponification of the polyvinyl alcohol is not particularly limited.
It can be selected from a range of about 0%, and is usually about 70 to 95%. As the modified polyvinyl alcohol, for example,
A completely or partially saponified product of a copolymer of vinyl acetate and a copolymerizable monomer (vinyl acetate copolymer) is exemplified. When using acetoacetyl-modified polyvinyl alcohol, the degree of saponification is usually about 60 to 95%.

Examples of the copolymerizable monomer constituting the vinyl acetate copolymer include olefins or dienes (eg, ethylene, propylene, butadiene, etc.), dialkyl maleate, and (meth) acrylic monomer. (Eg, alkyl (meth) acrylates such as methyl (meth) acrylate and ethyl (meth) acrylate, hydroxy-containing (meth) acrylates such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate, and glycidyl (Meth) acrylates, vinyl cyanides such as (meth) acrylonitrile, etc.), allyl monomers (eg, epoxy-containing monomers such as allyl alcohol, allyl isocyanate, allyl glycidyl ether, etc.), sulfonic acid groups or salts thereof. Monomers (such as styrene sulfonic acid and its sodium salt), monomers containing a carboxyl group or its salt (such as a carboxyl group such as (meth) acrylic acid, crotonic acid, and monoalkyl maleate or its salt), and acid anhydrides Group-containing monomers (such as maleic anhydride), vinyl monomers (aromatic vinyl monomers such as vinyl isocyanate and styrene, heterocyclic vinylamines such as vinyl pyrrolidone and vinyl imidazole, vinyl methyl ether, vinyl ethyl Vinyl ethers such as ether and vinyl isobutyl ether; hydrolyzable silyl group-containing monomers such as vinyl trisalkoxysilane; and halogen-containing vinyl monomers such as vinyl chloride and vinylidene chloride). These copolymerizable monomers can be used alone or in combination of two or more.

Preferred vinyl acetate copolymers include hydrophilic groups (for example, carboxyl groups,
Sulfonic acid groups, salts thereof, and ether groups). Especially ether group (among others, oxyalkylene unit)
The number of units (addition moles) of a vinyl monomer having, for example, an alkylene oxide is 1 to 100, preferably 2 to
80 (for example, 5 to 80), more preferably 5 to 70
A copolymer using (meth) acrylic acid ester or allyl ether of about (for example, 10 to 50) as a copolymerizable monomer is preferable. Examples of the vinyl monomer having an oxyalkylene unit include diethylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, dipropylene glycol mono (meth) acrylate, and tripropylene glycol mono ( (Meth) acrylate, polypropylene glycol mono (meth) acrylate, diethylene glycol mono (meth) allyl ether, triethylene glycol mono (meth) allyl ether, polyethylene glycol mono (meth) allyl ether, dipropylene glycol mono (meth) allyl ether, triethylene glycol mono (meth) allyl ether Propylene glycol mono (meth) allyl ether, polypropylene glycol mono (meth) allyl ether and the like are included. These vinyl monomers can be used alone or in combination of two or more. Preferred monomers include vinyl monomers in which the oxyalkylene unit is an oxyethylene unit (meth)
Acrylates, especially polyoxyalkylene (meth) allyl ethers (among others, polyoxyethylene allyl ethers) are included.

The proportion of the copolymerizable monomer can be selected within a range that does not impair the sharpness of the image, and is, for example, about 0.1 to 50 mol%, preferably about 1 to 30 mol%, more preferably about 1 to 30 mol% of the whole monomer. It is about 2.5 to 25 mol% (for example, 3 to 20 mol%).

Among the modified polyvinyl alcohols, a saponified product of a copolymer of vinyl acetate and a vinyl monomer having a polyoxyalkylene unit (for example, Nippon Synthetic Chemical Co., Ltd.)
Available under the trade name "OKS-7158G"), epoxy-modified polyvinyl alcohol and the like.

The epoxy-modified polyvinyl alcohol includes (1) saponification of a copolymer of vinyl acetate and a monomer having an epoxy group (such as allyl glycidyl ether and glycidyl (meth) acrylate); and (2) epichlorohydrin. By epoxidation of polyvinyl alcohol with an epoxidizing agent. The used amount (content) of the monomer containing an epoxy group and the introduced amount of the epoxy group are about 0.01 to 5 mol%, preferably 0.1 to 3 mol% (for example, 0.2 to 2.0 mol%). 5 mol%), especially 0.2 to
It is about 2 mol%.

The acrylic polymer containing a (meth) acrylic monomer having a hydroxyl group as a monomer component may contain a carboxyl group in addition to the hydroxyl group. The (meth) acrylic monomer having a hydroxyl group includes hydroxy C _2-6 alkyl (meth) acrylate- (meth) acrylic acid copolymer, hydroxy C _2-6 alkyl (meth) acrylate- (meth) acryl Acid C _1-12
Alkyl ester- (meth) acrylic acid copolymer “For example, methyl methacrylate-hydroxy C _2-6 alkyl (meth) acrylate- (meth) acrylic acid copolymer,
Methyl methacrylate-C _1-12 alkyl acrylate-hydroxy C _2-6 alkyl (meth) acrylate-
(Meth) acrylate copolymer, etc. ", styrene- (meth) acrylic acid C _1-12 alkyl ester-hydroxy C
Examples thereof include _2-6 alkyl (meth) acrylate copolymers. Acrylic polymers having a carboxyl group are salts.
(An ammonium salt, an amine salt, or an alkali metal salt such as sodium). If necessary, the acrylic polymer may be a copolymerizable monomer such as an epoxy group-containing (meth) acrylate, a vinyl cyanide, an allyl monomer, a sulfonic acid group, or a copolymerizable monomer exemplified in the section of the vinyl acetate copolymer. A monomer containing a salt thereof, a monomer containing an acid anhydride group, a vinyl monomer, etc. ", an amino group-containing (meth) acrylate, an amide group-containing monomer, etc. Is also good.

The content of the hydroxyl group in the acrylic polymer can be selected from a range of about 5 to 100% by weight, preferably about 5 to 75% by weight, more preferably about 5 to 50% by weight in terms of hydroxyethyl methacrylate.
Usually, it is about 10 to 30% by weight. The content of the carboxyl group in the acrylic polymer can be generally selected from a range of about 5 to 60% by weight, preferably about 10 to 50% by weight, and more preferably about 15 to 35% by weight in terms of methacrylic acid. [Crosslinking Agent] The crosslinking agent is not particularly limited as long as the hydrophilic polymer can be crosslinked. For example, when the hydrophilic polymer has a hydroxyl group, a compound having a carboxyl group or an acid anhydride group, a compound having an aldehyde group, a compound having an epoxy group, a nitrogen-containing compound, a compound having an acrylamide group, and an isocyanate group. Compounds, metal compounds, and the like, and polycarboxylic acids or acid anhydrides thereof, and metal compounds are particularly preferable. When the hydrophilic polymer has a carboxyl group, an epoxy group, an isocyanate group, a metal compound and the like can be used. These crosslinking agents can be used alone or in combination of two or more.

By combining a polycarboxylic acid or a salt thereof or an anhydride of a polycarboxylic acid with a hydroxyl group-containing hydrophilic polymer, bleeding of the ink can be suppressed even when the substrate is a nonwoven fabric, and ink absorption can be suppressed. Properties, anti-blocking properties and image clarity (print quality) can also be improved.

Examples of the polycarboxylic acid include compounds having two or more carboxyl groups in the molecule, such as aliphatic polycarboxylic acids (oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, C _2-10 aliphatic saturated polycarboxylic acids such as sebacic acid, fumaric acid, maleic acid, maleic anhydride,
Citraconic acid, mesaconic acid, etc. C _4-6 aliphatic unsaturated polycarboxylic acids such as itaconic acid), alicyclic polycarboxylic acid (1,4-cyclohexanedicarboxylic acid, tetrahydrophthalic acid, hexahydrophthalic acid, hymic acid C _8-10 alicyclic polycarboxylic acids, etc.), aromatic polycarboxylic acids (phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, etc.
_8-12 Aromatic polycarboxylic acid or acid anhydride thereof), oxypolycarboxylic acid (C _3-6 oxypolycarboxylic acid such as tartronic acid, malic acid, tartaric acid, citric acid, etc.), nitrogen, oxygen and sulfur Heterocyclic polycarboxylic acids having at least one heteroatom selected from atoms (pyridine dicarboxylic acid, pyridine tricarboxylic acid, pyridine tetracarboxylic acid, isosaccharide acid, tropic acid, etc.)
And the like. These polycarboxylic acids include aliphatic, cycloaliphatic or aromatic C _2-10 polycarboxylic acids (especially C ₃ -C).
₁₀ polycarboxylic acids).

Further, preferred polyvalent carboxylic acids are often water-soluble or water-dispersible, and at a temperature of 30 ° C., 5 g or more (preferably 10 g or more) per 100 g of water.
(More preferably 30 g or more). Such polycarboxylic acids include C _2-6
And aliphatic polycarboxylic acids (particularly, C _3-5 aliphatic polycarboxylic acids). As the polycarboxylic acid, maleic acid or an acid anhydride thereof (maleic anhydride) is particularly preferred.

The polycarboxylic acid may be used as a salt, and a part or all of the carboxyl group of the polycarboxylic acid may form a salt with a base. The polyvalent carboxylate includes a salt with an inorganic base (eg, an alkali metal such as ammonia, potassium, and sodium) and a salt with an organic base (eg, a tertiary amine).

Examples of the compound having an aldehyde group include compounds having a plurality of aldehyde groups, such as glyoxal, malondialdehyde, glutaraldehyde, terephthalaldehyde, dialdehyde starch, and acrolein copolymerized acrylic resin.

Examples of the compound having an epoxy group include compounds having a plurality of epoxy groups, for example, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl. Ether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, 1, 2-3, 4
-Diepoxybutane and the like.

Examples of the nitrogen-containing compound include C _1-4 alkoxy melamine such as methoxymethyl melamine;
-Methylol melamine, methylol group-containing compounds such as N-methylol urea, guanamines such as acetoguanamine and benzoguanamine, urea and melamine and / or condensates of urea and aldehyde (melamine-formalin resin,
Urea-formalin resin).

Examples of the compound having an acrylamide group include methylene-bis (meth) acrylamide, N, N '
-Dimethylol-methylene-bisacrylamide, 1,
Examples thereof include 1-bisacrylamide-ethane.

Examples of the compound having an isocyanate group include polyisocyanate compounds, for example, polyols such as tolylene diisocyanate, hydrogenated tolylene diisocyanate, diphenylmethane diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, hydrous polyester and polyether, and the above polyisocyanate. Are mixed excessively, and a prepolymer having an isocyanate group at a terminal previously polymerized can be exemplified.

As the metal compound, a water-soluble metal compound having a valence of 2 or more is preferable, and halogen such as boron, aluminum, iron, copper, zinc, tin, titanium, nickel, magnesium, vanadium, chromium, and zirconium is preferable. Examples include salts such as chlorides, carbonates, nitrates, and sulfates, oxides, and hydroxides. Particularly, boric acid, borax, aluminum chloride, aluminum sulfate, zirconium ammonium carbonate, zirconium chloride, iron alum and the like are preferable.

The proportion of the crosslinking agent used can be selected within a range that does not impair the properties such as ink absorbency and water resistance. For example, in terms of polyvalent carboxylic acid, 0.1 to 100 parts by weight of the hydrophilic polymer is used. About 40 parts by weight, preferably 0.5
About 30 parts by weight, more preferably about 1 to 20 parts by weight.

The ratio of the hydrophilic polymer and the crosslinking agent for treating the nonwoven fabric can be selected from a range which does not block the voids of the nonwoven fabric and can improve the water resistance of the ink. About 0.1 to 70 parts by weight, preferably about 0.5 to 50 parts by weight, more preferably 1 to
It is about 30 parts by weight.

[Granules] The granules may be contained in the hydrophilic polymer as required. By performing the treatment with the hydrophilic polymer containing the granular material, the printability and water resistance of the ink image receiving sheet are further improved. Examples of the powders include inorganic powders (silicon dioxide (white carbon, colloidal silica, etc.), particulate calcium silicate, zeolite, magnesium aminosilicate, calcined silica, particulate magnesium carbonate, particulate alumina, talc) , Kaolin, delamikaolin, clay, diatomaceous earth, heavy calcium carbonate, light calcium carbonate, zinc carbonate, magnesium carbonate, titanium dioxide, zinc oxide, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, magnesium silicate, aluminum silicate, sulfuric acid Mineral particles such as calcium, barium sulfate, sericite, bentonite, smectite, etc.), organic particles [crosslinked or non-crosslinked organic fine particles such as polystyrene resin, acrylic resin, urea resin, melamine resin, benzoguanamine resin, fine particles Hollow grain Include organic particulate material, etc.] and the like. One or more of these powders may be appropriately selected and used together. The average particle size is 10 nm to 20 μm, preferably 10 nm
It is about 10 nm to 10 μm (for example, 50 nm to 5 μm). In addition, when using a granular material, the said hydrophilic polymer can be used as a binder resin.

The ratio of the granular material to the hydrophilic polymer can be selected from a range that does not block the voids of the nonwoven fabric and does not impair the flexibility. For example, the ratio of the granular material to 100 parts by weight of the hydrophilic polymer is 0.1 to 40 (1 to 30) parts by weight, preferably about 0.2 to 30 (5 to 20) parts by weight;
It is about 20 parts by weight. If the amount of the powder exceeds 40 parts by weight, the texture is undesirably reduced.

Further, in order to improve the fixability of the colorant (dye), it is advantageous to use a dye fixing agent, particularly a high molecular dye fixing agent. The dye fixing agent (polymer dye fixing agent)
Usually, a cationic group (particularly, guanidyl group or
Quaternary ammonium salt type strong cation group).
The dye fixative may be water-soluble.

Examples of the dye fixing agent include dicyan fixing agents (dicyandiamide-formalin polycondensate), polyamine fixing agents [aliphatic polyamines such as diethylenetriamine, triethylenetetramine, dipropylenetriamine, polyallylamine, and phenylenediamine]. Such as aromatic polyamines, condensates of dicyandiamide and (poly) C _2-4 alkylene polyamine (eg, dicyandiamide-diethylenetriamine polycondensate), and polycationic fixing agents. Examples of the polycationic fixing agent include, for example, epichlorohydrin-di C
_1-4 alkylamine addition polymer (epichlorohydrin-
Dimethylamine addition polymer, etc.), polymer of allylamine or a salt thereof (polymer of polyallylamine or a hydrochloride thereof, for example, Nitto Boseki Co., Ltd., PAA-10C, PAA-HCl-3L,
PAA-HCl-10L, etc.), a polymer of diallyl C _1-4 alkylamine or a salt thereof (a polymer of diallylmethylamine or a hydrochloride thereof, for example, Nitto Boseki Co., Ltd., PAS-M-1, etc.), diallyldiamine Polymers of C _1-4 alkyl ammonium salts (polymers of diallyl dimethyl ammonium chloride, such as Nitto Boseki Co., Ltd., PAS-H-5L, PAS-H-10L, etc.), and diallylamine or a salt thereof with sulfur dioxide Copolymer (diallylamine hydrochloride-sulfur dioxide copolymer, such as Nitto Boseki Co., Ltd., PAS-92), diallyl di C _1-4 alkylammonium salt-sulfur dioxide copolymer (diallyldimethylammonium chloride-sulfur dioxide) Copolymers, for example, Nitto Boseki Co., Ltd., PAS-A-1,
PAS-A-5, PAS-A-120L, PAS-A-120A, etc.), a copolymer of diallyldi C _1-4 alkylammonium salt and diallylamine or a salt or derivative thereof (diallyldimethylammonium chloride-diallylamine hydrochloride derivative) Copolymer, for example, Nitto Boseki Co., Ltd., PAS-880),
Diallyl di C _1-4 alkyl ammonium salt polymer, di C
Polymer of _1-4 alkylaminoethyl (meth) acrylate quaternary salt, diallyldi C _1-4 alkylammonium salt-
Acrylamide copolymer (diallyldimethylammonium chloride-acrylamide copolymer, for example, Nitto Boseki Co., Ltd., PAS-J-81), amine-carboxylic acid copolymer (for example, Nitto Boseki Co., Ltd., PAS-410) Etc.) can be exemplified. These dye fixing agents may be used alone or in combination of two or more.

The amount of the dye fixing agent used is within a range capable of improving the fixing property, for example, 0.1 to 40 parts by weight, based on 100 parts by weight of the resin composition composed of a hydrophilic polymer, in terms of solid content. Preferably 1 to 30 parts by weight, more preferably 2 to 30 parts by weight
It can be selected from a range of about 20 parts by weight.

The hydrophilic polymer may contain, if necessary, other components such as an aqueous emulsion containing a non-crosslinkable polymer or polymer particles (for example, an acrylic resin emulsion, an ethylene-vinyl acetate copolymer emulsion, A vinyl acetate emulsion).

The hydrophilic polymer may be a conventional additive such as an antifoaming agent, a coating improver, or the like, as long as the properties are not impaired.
Thickeners, lubricants, stabilizers (such as antioxidants, ultraviolet absorbers, and heat stabilizers), antistatic agents, and antiblocking agents may be added.

The ink receiving sheet of the present invention may be used by laminating it on a support (for example, paper, coated paper, plastic film, etc.). [Method of Manufacturing Ink Image Receiving Sheet] The ink image receiving sheet of the present invention can be manufactured by treating a nonwoven fabric with a hydrophilic polymer, a cross-linking agent and, if necessary, a granular material.

The treatment method may be any method as long as at least the nonwoven fabric is coated with a hydrophilic polymer, a crosslinking agent, and, if necessary, a powder. As such a treatment method, for example, a treatment method of immersing in a treatment liquid containing a hydrophilic polymer and a crosslinking agent and, if necessary, a granular material, or coating the treatment liquid by coating (coating, spraying, etc.) or the like. Processing methods and the like can be mentioned. The coating treatment includes a conventional casting or coating method such as a roll coater, an air knife coater, a blade coater, a rod coater, a bar coater, a comma coater, a gravure coater, and a silk screen coater method.

The treatment can be appropriately carried out as long as the hydrophilic polymer, the crosslinking agent and the powdery material coexist if necessary on the nonwoven fabric. Both may be mixed and processed at the same time, or one of them may be processed and then the other may be processed.
It is preferable to treat the powdery particles by mixing with a hydrophilic polymer, but the present invention is not limited to this method.

The above-mentioned ink image-receiving sheet is obtained by performing the above-mentioned treatment and, if necessary, drying it.

In the ink receiving sheet of the present invention, since the nonwoven fabric is treated with a hydrophilic polymer, a crosslinking agent and, if necessary, a granular material, a clear and sharp image can be obtained by suppressing ink bleeding. At the same time, ink absorbency, ink fixability, printability, and water resistance can be improved.

The ink receiving sheet of the present invention is useful as an ink receiving sheet of an ink jet system for recording by flying small ink droplets. ) Can also be used.

[0055]

The ink image-receiving sheet of the present invention is formed by treating a nonwoven fabric with a hydrophilic polymer, a crosslinking agent and, if necessary, a powdery material, so that a clear image can be formed by suppressing ink bleeding. At the same time, even a non-woven fabric is excellent in printability, and can improve ink absorption, ink fixability, and water resistance.

[0056]

The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, parts or%
Is based on weight. The hydrophilic polymer, crosslinking agent, powder and nonwoven fabric used in the examples and comparative examples are as follows.

A. Hydrophilic polymer (a-1): modified polyvinyl alcohol (trade name "OKS7158G", manufactured by Nippon Synthetic Chemical Industry Co., Ltd., degree of saponification 88%) (a-2): polyacrylic acid (Scientific Polymer)
Products). Crosslinking agent (b-1): maleic acid (manufactured by Wako Pure Chemical Industries, Ltd.) (10 parts by weight based on 100 parts by weight of modified polyvinyl alcohol in terms of weight) (b-2): zirconium chloride (manufactured by Merck) (20 parts by weight per 100 parts by weight of polyacrylic acid in terms of weight) Powder (c-1): silicon dioxide (manufactured by Fuji Silysia Chemical Ltd.,
(C-2): diatomaceous earth (manufactured by Showa Chemical Co., Ltd., trade name "diatomaceous earth F") Nonwoven fabric (d-1): Polyester nonwoven fabric (Japan Vilene (
Co., Ltd., trade name “MF-180K”, average fiber diameter 15μ
m, basis weight 180 g / m ² , thickness 200 μm, fiber density 900 kg / m ³ , air permeability 2.0 cm ³ / cm ² · se
c) (d-2): polyester nonwoven fabric (Japan Vilene (
Co., Ltd., trade name “MF-135K”, average fiber diameter 15μ
m, basis weight 135 g / m ² , thickness 150 μm, fiber density 867 kg / m ³ , air permeability 1.9 cm ³ / cm ² · se
c) In the ink image receiving sheets obtained in Examples and Comparative Examples, water resistance and printability were evaluated as follows.

An ink jet printer (ENCAD)
NOVAJET. PRO), a pigment-type aqueous ink (each color of cyan, yellow, magenta, and black) was solidly printed on the ink receiving sheets obtained in Examples and Comparative Examples to form a recorded image.

[Water Resistance] The printed area was rubbed 10 times with a cotton swab sufficiently containing water at 25 ° C., and the printed area was visually evaluated according to the following criteria. ◎ The printed portion remains completely. 滲 The bleeding is observed in the printed portion. × The printed portion does not remain. [Printability] The printed image forming portion was visually evaluated according to the following criteria. ◎ Vivid, no bleeding ○ Slight bleeding × Intense bleeding [Ink absorbency] After printing, place the PPC copy paper on the printing unit at regular intervals and apply a load of 2
After applying 50 g / cm ² for 10 seconds, the copy paper was peeled off, the degree of ink set-off was visually determined, and the ink absorption was evaluated based on the time until no set-off was recognized.

Example 1 A non-woven fabric (d-1) was coated with a coating solution containing a 10% by weight aqueous solution of denatured polyvinyl alcohol (a-1) and a crosslinking agent (b-1) using a bar coater No. 40. By drying in a dryer at 10 ° C. for 10 minutes, an ink image-receiving sheet was obtained. An image was formed on this image receiving sheet with an inkjet printer.

Example 2 A coating solution containing a 20% by weight aqueous solution of modified polyvinyl alcohol (a-1) and a crosslinking agent (b-1) was applied to the nonwoven fabric (d-1) using a bar coater No. 40, and By drying in a dryer at 10 ° C. for 10 minutes, an ink image-receiving sheet was obtained. An image was formed on this image receiving sheet with an inkjet printer.

Example 3 A non-woven fabric (d-2) was coated with a coating liquid containing a 10% by weight aqueous solution of modified polyvinyl alcohol (a-1) and a crosslinking agent (b-1) using a bar coater No. 40, By drying in a dryer at 10 ° C. for 10 minutes, an ink image-receiving sheet was obtained. An image was formed on this image receiving sheet with an inkjet printer.

Example 4 A 10% by weight polyacrylic acid (a-
2) A coating solution containing an aqueous solution and a crosslinking agent (b-2) was applied using a bar coater No. 40, and dried in a dryer at 120 ° C. for 10 minutes to obtain an ink image receiving sheet. An image was formed on this image receiving sheet with an inkjet printer.

Example 5 A non-woven fabric (d-1) containing 10% by weight of a modified polyvinyl alcohol (a-1) aqueous solution and a crosslinking agent (b-1) was mixed with 80 parts by weight (in terms of solid content) of powder. Granules (c-1)
Was applied with a bar coater No. 40 and dried in a dryer at 120 ° C. for 10 minutes to obtain an ink image-receiving sheet. An image was formed on this image receiving sheet with an inkjet printer.

Example 6 A non-woven fabric (d-1) containing 90% by weight (in terms of solid content) of a dope containing a 10% by weight aqueous solution of a modified polyvinyl alcohol (a-1) and a crosslinking agent (b-1) was powdered. Granules (c-2)
Was applied with a bar coater No. 40 and dried in a dryer at 120 ° C. for 10 minutes to obtain an ink image-receiving sheet. An image was formed on this image receiving sheet with an inkjet printer.

Comparative Example 1 An ink image-receiving sheet was obtained in the same manner as in Example 1 except that the nonwoven fabric was changed to a polyethylene terephthalate film. An image was formed on this image receiving sheet with an inkjet printer.

Comparative Example 2 An ink image-receiving sheet was obtained in the same manner as in Example 4 except that the nonwoven fabric was changed to a polyethylene terephthalate film. An image was formed on this image receiving sheet with an inkjet printer.

Comparative Example 3 The nonwoven fabric (d-1) was used as an ink receiving sheet without any processing, and an image was formed on the image receiving sheet by an ink jet printer.

Comparative Example 4 A non-woven fabric (d-1) was coated with a 10% by weight aqueous solution of modified polyvinyl alcohol (a-1) using a bar coater No. 40, and dried in a dryer at 110 ° C. for 10 minutes to obtain an ink. An image receiving sheet was obtained. An image was formed on this image receiving sheet with an inkjet printer.

Comparative Example 5 A 30% by weight aqueous solution of a crosslinking agent (b-1) was applied to the nonwoven fabric (d-1) with a bar coater No. 40, and dried in a dryer at 110 ° C. for 10 minutes to obtain an ink image. I got a sheet. An image was formed on this image receiving sheet with an inkjet printer.

Table 1 shows the results of evaluating the characteristics of the ink image receiving sheets obtained in Examples and Comparative Examples.

[0072]

[Table 1] As is clear from Table 1, the ink receiving sheets of the examples have good printability, water resistance and ink absorbency. On the other hand, the ink image receiving sheets of Comparative Examples 1 and 2 have relatively good printability and water resistance, but have insufficient ink absorbency. The ink image receiving sheets of Comparative Examples 3 to 5 have relatively good ink absorbency, but do not have sufficient water resistance.

Claims (8)

[Claims] 1. An ink receiving sheet, wherein at least one surface of a nonwoven fabric is treated with at least a hydrophilic polymer and a crosslinking agent. 2. The ink image receiving sheet according to claim 1, wherein the ink image receiving sheet is treated with a hydrophilic polymer, a crosslinking agent, and a granular material. 3. The ink image-receiving sheet according to claim 1, wherein the hydrophilic polymer has at least a hydroxyl group. 4. The ink image receiving sheet according to claim 1, wherein the hydrophilic polymer is polyvinyl alcohol or modified polyvinyl alcohol. 5. The ink image receiving sheet according to claim 1, wherein the crosslinking agent is a polycarboxylic acid or an acid anhydride thereof. 6. The ink image receiving sheet according to claim 1, wherein the crosslinking agent is maleic acid or an acid anhydride thereof. 7. The ink image-receiving sheet according to claim 2, wherein 0.1 to 40 parts by weight of the powder is blended with respect to 100 parts by weight of the hydrophilic polymer. 8. A method for producing an ink image-receiving sheet, comprising treating a nonwoven fabric with at least a hydrophilic polymer and a crosslinking agent.