JPH11170685A - Recorded medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To raise an ink absorptive ability, water resistivity, and anti-beading property by forming an ink receptor layer furnished on the support body of a medium to be recorded from a block copolymer of a water soluble monomer and nonwater soluble monomer. SOLUTION: A medium to be recorded used for an ink jet recording medium include an ink receptor layer on a support body; however, the ink receptor layer is formed of a water soluble monomer and a nonwater soluble monomer. The water soluble monomer is a matter capable of forming a uniform solution being about 10 wt.% or more at an ordinary temperature and pressure, and although not being limited in particular, a substance is given having, e.g. a hydrophilic group such as a hydroxyl group and a sulfinic acid group and including one or more reactive double bonds in one molecule. While, the nonwater soluble monomer includes one or more reactive double bonds in one molecular, and is not capable of forming a solution having a density of about 10 wt.% or more at an ordinary temperature and pressure, for which methyl (meth)acrylic acid or the like is given for example.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium used for ink jet recording, and more particularly to a recording medium in which ink is rapidly and uniformly absorbed, has water resistance, and has little beading.

[0002]

2. Description of the Related Art An ink jet recording system in which minute droplets of ink are caused to fly by various operating principles and adhere to a recording medium such as paper to record images, characters, and the like has a high speed and low noise. Due to its features such as easy multi-coloring, in recent years, it has rapidly spread in various applications, such as information equipment, as a recording device for various images.

[0003] The ink used in this ink jet recording system is obtained by diluting a coloring material into water or a water-like solvent mainly containing alcohols such as ethylene glycol and isopropanol.

In order to form an image or the like on a recording medium with the ink, the solvent in the ink is absorbed and
In addition, it is desirable that a so-called ink receiving layer for holding the color material is provided on the recording medium.

When ink is penetrated into ordinary paper or the like having no ink receiving layer, the ink often bleeds or the paper oozes, and the color density and the resolution of images and the like are reduced, and the appearance is improved. Good images cannot be obtained. Further, when a normal resin film or the like without an ink receiving layer is used as a recording medium, the ink is repelled, so that an image or the like cannot be formed stably.

Therefore, when a high-resolution image or the like is desired, a coated paper in which paper is coated with an ink receiving layer and a coated film in which a resin film is coated with an ink receiving layer are used as recording media.

In order for the ink receiving layer to sufficiently exhibit the ink absorbing performance, the ink receiving layer has a water absorbing property enough to absorb the ink immediately after the ink droplet ejected from the ink jet head lands, and the ink absorbing layer absorbs the ink. It is necessary to use a material having a performance capable of fixing the ink.

As a material for such an ink receiving layer,
Water-soluble resins such as polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol and polyacrylic acid are used. For example, JP-A-4-251784 discloses polyvinyl alcohol or a modified product thereof,
JP-A-288283 discloses an ink receiving layer using a modified product of polyvinylpyrrolidone.

In a recording medium using such a water-soluble resin for the ink receiving layer, when ink droplets are ejected from an ink jet head and land on the ink receiving layer, the resin at the landed portion is partially removed. Dissolves or swells. At this time, the solvent in the ink is immediately taken into the resin of the ink receiving layer, and at the same time, the coloring material in the ink is also taken into the resin of the ink receiving layer, whereby an image or the like is formed.

However, such an ink receiving layer that immediately absorbs ink readily dissolves or swells in water, and therefore has extremely low water resistance. Therefore, when the recording medium having such an ink receiving layer, on which an image or the like is recorded, comes into contact with the hand wet with sweat, the sweat is absorbed into the ink receiving layer, and the trace of the sweat absorption There are problems such as remaining ink, ink bleeding, and the ink receiving layer dissolving, swelling and falling off. For this reason, there is a problem that it is difficult to use it for outdoor applications where water is likely to be splashed, leaflets and flyers used for advertisements, price tags for fresh foods, bar coat labels, and the like.

Also, in the case of a transparency sheet for an overhead projector which is a general use different from the above-mentioned use or a glossy film capable of obtaining a high-quality image equivalent to a photographic image, sweat and the like are easily absorbed. Then, if the ink oozes, it becomes a big problem.

JP-A-4-201595 discloses a method of forming a water-resistant ink-receiving layer by copolymerizing polyvinyl alcohol or polyvinylpyrrolidone with a hydrophobic material such as styrene. Also,
Japanese Patent Application Laid-Open No. 4-251784 discloses a method in which the degree of saponification and the degree of polymerization of polyvinyl alcohol are selected so as to be within suitable ranges, and further, the water resistance is improved by adding polyvinyl acetate or the like. .

However, when the water resistance is improved in this manner, the dissolving and swelling performance of the ink receiving layer by the ink is reduced, so that the ink absorbing performance of the ink receiving layer is reduced. When the ink absorption performance is reduced, not only does it take time to dry the ink, but also the unabsorbed ink is mixed and discolored, or the unabsorbed ink flows and the outline of an image or the like is broken. A fatal problem occurs as a recording medium.

In this case, it is possible to increase the penetration rate by providing a large number of very fine openings on the surface of the ink receiving layer. It is fragile and easily lacks in practicality, and it is difficult to produce a fine hole whose size and distribution are controlled.

It is also conceivable to use silica, alumina, or the like having fine pores, but it is difficult to obtain an ink receiving layer using these materials and having sufficient ink absorption performance. Japanese Patent Application Laid-Open No. 6-199034 discloses a recording medium using a boehmite sol for an ink receiving layer. However, there are problems such as an increase in manufacturing cost and an inability to obtain sufficient ink absorption performance. Was.

Further, the ink receiving layer has another problem that beading easily occurs. This beading occurs because the ink droplets printed on the recording medium aggregate and become large droplets in the process of being absorbed,
Visually, it is recognized as color unevenness of about 1 mm.

JP-A-55-29546 and JP-A-6-29546
Japanese Patent No. -24123 discloses a method for improving the permeability of an ink by adding a surfactant to the ink.
However, the ink containing the surfactant can be used for plain paper, but on a recording medium having an ink receiving layer provided on a support, the ink absorbability deteriorates, There is a problem that dinging easily occurs.

[0018] Japanese Patent Application Laid-Open Nos.
Japanese Patent No. 297831 discloses a recording medium having an ink receiving layer in which beading is prevented by increasing the ink absorption speed and absorption amount. However, beading also depends on the amount of dye fixed in the ink and the fixing speed, so that beading could not be completely prevented only by increasing the ink absorption speed or the like.

JP-A-61-237682, JP-A-62-204990 and JP-A-1-133779
JP-A-3-45378 and JP-A-3-45378 disclose a recording medium having a hydrophobic substance inside or on the surface of an ink receiving layer made of a hydrophilic resin.
JP-A-130187 discloses a recording medium having an ink receiving layer whose contact angle with respect to ink or the like is adjusted. All of these methods reduce the dot diameter of printed ink droplets by reducing the wettability of the surface of the ink receiving layer, so that the aggregated droplets aggregate before the ink is absorbed. It is to prevent. However, in such an ink receiving layer, there is a problem that since the wettability of the ink receiving layer is deteriorated, the ink absorbing speed is reduced, and beading is more likely to occur when the ink amount is increased.

[0020]

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a recording medium having an ink receiving layer used in an ink jet recording system, which has both excellent ink absorption performance and water resistance and beading resistance. It is an object to provide a recording medium excellent in performance.

[0021]

The present invention relates to a recording medium having an ink receiving layer on a support, wherein the ink receiving layer comprises a block copolymer of a water-soluble monomer and a water-insoluble monomer. A recording medium characterized by comprising: Hereinafter, the present invention will be described in detail.

The recording medium of the present invention is a recording medium having an ink receiving layer on a support, and the ink receiving layer is made of a block copolymer of a water-soluble monomer and a water-insoluble monomer. The water-soluble monomer is capable of forming a uniform aqueous solution of 10% by weight or more at normal temperature and normal pressure. However, even if heating is required at the time of dissolution, the monomer is assumed to be capable of forming a uniform aqueous solution unless separation or precipitation occurs at normal temperature and normal pressure thereafter. Further, the water-soluble monomer,
Those having high water solubility and capable of forming an aqueous solution at an arbitrary concentration are preferable.

Examples of the water-soluble monomer include a hydroxyl group, a sulfonic acid group, a sulfonate group, a primary, secondary or tertiary amino group; a primary, secondary or tertiary amide group; an ammonium base, and a carboxylic acid group. , A carboxylate group, a phosphate group,
Those having a hydrophilic group such as a phosphate group, a polyethylene glycol chain, a polyoxyalkylene chain, a morpholino group, a sulfate group, and containing one or more reactive double bonds in one molecule are exemplified. Among the above hydrophilic groups, those having an acidic group or a basic group may be used after being neutralized in advance.

The water-soluble monomer is not particularly limited as long as it has the above-mentioned hydrophilic group. For example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, glycerol (meth)
Acrylate, 2-acrylamido-2-methylpropanesulfonic acid, sodium ethyl sulfonate (meth) acrylate, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, Glucosiethyl (meth) acrylate, N-isopropylacrylamide, N, N-dimethylaminopropylacrylamide,
2-methacryloxyethyltrimethylammonium chloride, (meth) acrylic acid, sodium (meth) acrylate, 2- (meth) acryloyloxyethylsuccinic acid, 2- (meth) acryloyloxyethylphthalic acid,
2- (meth) acryloyloxyethyl hexahydrophthalic acid, ω-carboxy-polycaprolactone monoacrylate, EO-modified phosphoric acid (meth) acrylate, polyethylene glycol (meth) acrylate, acryloylmorpholine, p-styrenesulfonic acid, vinylsulfonic acid , Allylsulfonic acid, ethyl (meth) acrylatesulfonic acid, water-soluble urethane-modified acrylate, polyethylene glycol di (meth) acrylate, polyethylene glycol mono (meth) acrylate, and the like.

Examples of the water-soluble urethane-modified acrylate include, for example, UA-W1, U-W1 manufactured by Shin-Nakamura Chemical Co., Ltd.
A-W2, UA-W3, UA-W4, UA-W61, U
A-W62, UA-W63 and the like. As the polyethylene glycol di (meth) acrylate, for example, NK esters A-200 and A-400 manufactured by Shin-Nakamura Chemical Co., Ltd.
A-600, A-1000, 4G, 9G, 14G, 23
G: Kyoei Chemical Co., Ltd. light ester 4EG, 9EG, 1
4EG, 9EG-A, 14EG-A and the like. As the polyethylene glycol mono (meth) acrylate,
For example, NK ester AMP-10 manufactured by Shin-Nakamura Chemical Co., Ltd.
G, AMP-20G, AMP-60G, AMP-90
G: Kyoei Chemical Co., light ester MC, 130MA,
041MA and the like. The water-soluble monomers may be used alone or in combination of two or more. The water-soluble polymer block of the block copolymer may contain monomer components other than the water-soluble monomer, such as styrene and (meth) acrylic acid ester. Needs to be

The water-insoluble monomer contains one or more reactive double bonds in one molecule, is less soluble than the water-soluble monomer, and has a concentration of 10% by weight or more at room temperature and pressure. Cannot form an aqueous solution.

Examples of the water-insoluble monomer include, for example,
(Meth) acrylic acid esters having 4 to 21 carbon atoms, such as methyl (meth) acrylate, ethyl (meth) acrylate, octyl (meth) acrylate, and stearyl (meth) acrylate; styrene, α-methylstyrene, Styrene monomers such as vinyl toluene; methyl vinyl ether,
Vinyl ether monomers such as ethyl vinyl ether and isobutyl vinyl ether; itaconic acid ester monomers such as fumaric acid, monoalkyl esters of phthalic acid and dialkyl esters of fumaric acid; (meth) acrylonitrile, butadiene, isoprene, vinyl chloride, vinylidene chloride, acetic acid Vinyl, vinyl ketone, vinyl pyrrolidone, vinyl pyridine, (meth) acrylamide, vinyl carbazole and the like can be mentioned.

The water-insoluble polymer block preferably has a glass transition temperature of 40 ° C. or higher. Examples of a monomer capable of synthesizing a water-insoluble polymer block having a glass transition temperature of 40 ° C or higher include, for example, methyl methacrylate, ethyl methacrylate, t-butyl methacrylate,
Methacrylic acid esters having 4 to 10 carbon atoms such as phenyl methacrylate; styrene-based monomers such as styrene, α-methylstyrene and vinyltoluene; itaconic acids such as fumaric acid, monoalkyl esters of fumaric acid, and dialkyl esters of fumaric acid Ester monomers: (meth) acrylonitrile, vinyl chloride, vinylidene chloride, vinyl ketone, vinyl pyrrolidone, vinyl pyridine, (meth) acrylamide, vinyl carbazole and the like.

The above water-insoluble polymer block having a glass transition temperature of 40 ° C. or more may contain the above-mentioned monomer alone, or two or more kinds thereof may be used in combination to constitute a copolymer. . The water-insoluble polymer block may contain another water-soluble monomer or a water-insoluble monomer as long as the glass transition point becomes water-insoluble at 40 ° C. or higher.

The type of the block copolymer of the present invention is not particularly limited. Examples thereof include a block copolymer of a water-soluble monomer and a macromonomer having a water-insoluble polymer in a side chain, a polyfunctional peroxide or a peroxide. A block copolymer obtained by reacting a water-soluble monomer with a copolymer of a monomer and a water-insoluble monomer is preferred.

Examples of the polyfunctional peroxide include 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, poly (azolyl peroxide), and poly (2,5- Dimethyl-2,5-diperoxyazelate), 1,1-di-t-butylperoxy-2-methylcyclohexane and the like. Examples of the peroxide monomer include t-butyl peroxyallyl carbonate, t-butyl peroxyvinyl carbonate and the like.

The macromonomer having a water-insoluble polymer in the side chain is not particularly limited as long as it has a group having a polymerizable unsaturated double bond bonded to the terminal of the water-insoluble polymer. Styrene, a copolymer of styrene and acrylonitrile, a polymer in which a (meth) acryloyl group is bonded to the terminal of a polymer such as methyl methacrylate, butyl acrylate, or silicone (AA-6 manufactured by Toa Gosei Chemical), ethylene and butylene Having a (meth) acryloyl group bonded to the terminal of the copolymer (Clayton Kid HPVM-1253 manufactured by Shell Co., Ltd.)
(Terminal methacryloyl group), Clayton Kid HPVM
-1213 (terminal acryloyl group)), and a (meth) acryloyl group bonded to the terminal of polypropylene (manufactured by Tonen Co., Ltd.). In the present invention, the weight average molecular weight of the block copolymer is preferably 5,000 to 5,000,000. More preferably, it is 50,000 to 500,000.

In the above block copolymer, 100 parts by weight or less of a non-block copolymer may be mixed with 10 parts by weight of the block copolymer. The non-block copolymer refers to a polymer or a copolymer having no block structure composed of a water-soluble monomer or a water-insoluble monomer, but among the monomers constituting the block copolymer, It is preferable that at least one of the above non-block copolymers is contained as a monomer.
Depending on the production method of the block copolymer, the yield of the block copolymer may be low, so that the resulting product may be a mixture of the block copolymer and the non-block copolymer.

The above block copolymer may contain a hydrophilic resin such as polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polyvinyl butyral, or a water-absorbing resin. It may contain a polymerized resin.

As a method for synthesizing the block copolymer, for example, a polyfunctional peroxide or a peroxide monomer is copolymerized with a water-insoluble monomer, and the obtained polymer is mixed with a water-soluble monomer. After polymerizing the polymerizable composition, a method of copolymerizing by heating or the like, a macromonomer having a side chain of a water-insoluble polymer mixed with a water-soluble monomer to form a polymerizable composition, and copolymerized by light or heat And the like.

In this case, in order to secure the adhesion or anchoring property to the support, after preparing the above polymerizable composition,
It is preferable that the polymerizable composition is coated on a support to cause a polymerization reaction. In the method of coating the support after synthesizing the block copolymer, the adhesion to the support and the like become weak.

In the ink receiving layer composed of the block copolymer of the water-soluble monomer and the water-insoluble monomer, the water-soluble polymer block has an average particle size of 100 μm or less from the viewpoint of improving beading resistance. It is preferable to adopt a phase separation structure that becomes an island phase having a particle size.

The weight ratio of the water-insoluble polymer block to 100 parts by weight of the water-soluble polymer block in the ink receiving layer is preferably from 10 to 200 parts by weight. The thickness of the ink receiving layer is preferably from 1 to 100 μm.
If it is less than 1 μm, the absolute amount of ink absorption will be insufficient and it will not be possible to absorb the ink. If it exceeds 100 μm, a large amount of coating liquid will be required, which is not only uneconomical, but also causes Shrinks and curls easily. More preferably, it is 3 to 30 μm.

The ink receiving layer may contain a volatile solvent in addition to the block copolymer. The volatile solvent is not particularly limited and includes, for example, water; methanol, ethanol, isopropanol, butanol,
Alcohols such as ethylene glycol; ketones such as acetone, cyclohexanone, 2-butanone, and methyl isobutyl ketone; esters such as butyl acetate and ethyl acetate; tetrahydrofuran, dioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether; Ethers such as ethylene glycol diethyl ether; aromatic hydrocarbons such as toluene and xylene; hexane, cyclohexane, heptane, octane,
Hydrocarbons such as decane; amines such as triethylamine and pyrrole; amides such as N-methylpyrrolidone; and halogenated hydrocarbons such as chloroform and trichlorobenzene. These may be used alone or in combination of two or more.

When the ink receiving layer contains a volatile solvent, the weight ratio of the volatile solvent to 100 parts by weight of the water-soluble monomer is preferably 20 to 2,000 parts by weight. 20
If it exceeds 00 parts by weight, the concentration of the water-soluble monomer or the like is greatly reduced, so that when forming a coating film, it becomes difficult to apply the polymerizable composition so as to have an appropriate film thickness, In addition, the reaction hardly proceeds during curing. More preferably, it is 50 to 2000 parts by weight.

The content of the volatile solvent is simply
The amount of the volatile solvent may be used, but more precisely, it can be determined by comparing the mass of the polymerizable composition applied before curing with the mass after the volatile solvent is volatilized after curing. it can. 20 per 100 parts by weight of water-soluble monomer
An ink receiving layer containing a volatile solvent in an amount of not less than parts by weight has excellent ink absorbability and does not curl even when absorbing the ink.

Further, in order to improve the ink fixing property of the ink receiving layer and suppress stickiness, the ink receiving layer may contain one or more kinds of fine particles. Examples of the fine particles include silica, alumina, boehmite, diaspore, bayerite, beryllium oxide, cadmium oxide,
Cobalt hydroxide, copper hydroxide, copper oxide, iron hydroxide, iron oxide, goethite, lepidocrocite, manganese hydroxide,
Magnesium hydroxide, nickel oxide, nickel hydroxide,
Metal oxides and hydroxides such as thorium oxide, tin oxide, titanium oxide, yttrium oxide, zinc oxide and lanthanum oxide; porous fine particles made of organic polymers such as polystyrene gel;

In order to more effectively fix the ink on the ink receiving layer, it is preferable to use particles having an isoelectric point of 5 to 13 among the above-mentioned fine particles. The above isoelectric point can be determined by a general method such as a streaming potential method, an electroosmosis method, and an electrophoresis method, and the method of measuring the isoelectric point is referred to as “interfacial electric phenomenon” (Fumio Kitahara, Watanabe, published by Kyoritsu Shuppan Co., Ltd.) For typical particles, for example, see “Chemical Handbook Revised 3rd Edition”
(Issued by Maruzen Co., Ltd.) and the like.

In addition, fine particles made of a synthetic organic polymer such as polystyrene synthesized by saponification polymerization or colloidal silica may be used for coating the surface. The particle size of these fine particles is preferably 5 nm or more and 10 μm or less. 5n
If it is less than m, it is difficult to manufacture stably,
If it exceeds 10 μm, the fine particles present on the surface of the ink receiving layer are liable to be peeled off, and at the same time, the gloss of the surface may be lost. 5n to ensure transparency
m or more and 100 nm or less are more preferable.

The ink receiving layer contains amines such as triethylamine and triethanolamine, and ammonium salts such as tetramethylammonium chloride, dibutyldimethylammonium chloride and trimethylstearylammonium chloride as a fixing agent for the ink. You may. Further, known additives such as antioxidants, plasticizers, pigments and surfactants may be added to the ink receiving layer.

In the present invention, in order to improve the water resistance of the ink receiving layer, a chemical cross-link may be formed in the block copolymer. As a method for forming a chemical crosslink, a method for adding a compound having two or more reactive unsaturated double bonds in one molecule to a solution for synthesizing the block copolymer, a method for forming an ink receiving layer, For example, a method of adding a cross-linking agent capable of reacting with the synthesized block copolymer and reacting the block copolymer may be used.

In the above molecule, two or more reactive unsaturated groups 2
Examples of the compound having a heavy bond include alkylene glycol-type di (meth) acrylates such as 1,6-hexanediol di (meth) acrylate; tetraethylene glycol di (meth) acrylate and tripropylene glycol di (meth) acrylate Di (meth) acrylates of the polyethylene glycol or polypropylene glycol type; di (meth) acrylate of ethylene oxide adduct of bisphenol A; glycerin methacrylate acrylate, trimethylolpropane tri (meth)
Tri (meth) acrylates such as acrylate; and tetra (meth) acrylates such as pentaerythritol tetra (meth) acrylate.

The type of the crosslinking agent capable of reacting with the block copolymer is determined depending on what kind of functional group the block copolymer has. Examples of the functional group of the block copolymer include a hydroxyl group, a carboxyl group, an epoxy group, a mercapto group, an amino group, an isocyanate group, and an ester group.

The crosslinking agent capable of reacting with the above hydroxyl group includes
For example, tolylene diisocyanate (TDI), toluylene diisocyanate (TODI), xylylene diisocyanate, diphenylmethane diisocyanate (MD
Aromatic diisocyanate compounds such as I); aliphatic or alicyclic diisocyanate compounds such as hexamethylene diisocyanate (HMDI) and isophorone diisocyanate (IDI); tolylene diisocyanate trimer adduct of trimethylolpropane; triphenylmethane triisocyanate And triisocyanate compounds such as methylenebis (4-phenylmethane) triisocyanate; and alkoxysilanes such as trimethoxysilane, triethoxysilane and tributoxysilane.

Examples of the crosslinking agent capable of reacting with the carboxyl group include N, N'-hexamethylene-1,6-
Bis (1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, N, N′-diphenylmethane-4,4-bis (1-
Aziridine compounds such as aziridinecarboxamide) and trimethylolpropane-tri-β- (2-methylaziridine) propionate.

Examples of the crosslinking agent capable of reacting with both the hydroxyl group and the carboxyl group include, for example, ethylene glycol glycidyl ether, triglycidyl ether,
1,6-hexanediol glycidyl ether, trimethylolpropane triglycidyl ether, diglycidylaniline, N, N, N ', N'-tetraglycidyl-
Epoxy compounds such as m-xylylenediamine, 1,3-bis (N, N'-diglycidylaminomethyl) cyclohexane, and the like.

Examples of the crosslinking agent capable of reacting with the epoxy group include an acid anhydride, a compound having two or more carboxyl groups in one molecule, and a compound having two or more amino groups in one molecule. No.

The compound capable of reacting with the mercapto group includes, for example, di- or trimethylolphenol resin,
A di- or triisocyanate compound, a compound having two or more epoxy groups in one molecule, and the like can be given. Examples of the crosslinking agent capable of reacting with an amino group include a di- or tri-isocyanate compound, a compound having two or more epoxy groups in one molecule, and the like.

Examples of the crosslinking agent capable of reacting with the isocyanate group include compounds having two or more hydroxyl groups in one molecule such as diol and triol, compounds having two or more amino groups in one molecule, Compounds having two or more carboxyl groups in the molecule, polymercaptan and the like can be mentioned. Examples of the compound capable of reacting with the ester group include amino compounds such as triethylenetetramine and an aminosilane coupling agent.

In the recording medium of the present invention, the ink receiving layer is provided on the support. The support is not particularly limited. For example, in addition to plastic films or sheets, paper, various plastic molded articles, wood used for furniture and building materials, etc .; glass such as show window, metal, cement, pottery, etc. Various materials and articles.

The material of the plastic film or sheet is not particularly limited, and examples thereof include general-purpose resins such as polyethylene terephthalate, polymethyl methacrylate, polycarbonate, polyvinyl chloride, and polystyrene. Further, in the case of polyolefin, fluorine resin, or the like, it is preferable that a corona treatment or the like is performed to improve the adhesion. As the general-purpose resin, a resin to which a means for improving adhesion such as corona treatment or mat treatment may be used.

The above-mentioned plastic film or sheet may be transparent or opaque, colorless or colored. In the case of a colorless and transparent film, for example, it can be used as a transparency sheet for an overhead projector, and if it is white or colored, a high-quality image recording medium to be used for catalogs or the like, or It can be used for applications such as displays and signboards.

The above paper is not particularly limited, but from the viewpoint of adhesion to a hydrophilic resin or a water-absorbing resin or suitability for coating, synthetic paper made of polyolefin or polyester, or a paper obtained by laminating a plastic film on paper Or those having a coat layer made of plastic on paper are more preferable. The thickness, width, and the like of the support are not particularly limited, but it is realistic that the width and thickness allow ink jet recording.

The method of manufacturing the recording medium having the above-described configuration is not particularly limited.
The following production methods are mentioned. First, as a first method, a liquid obtained by mixing a polyfunctional peroxide or a peroxide monomer, a water-insoluble monomer, a photopolymerization initiator, and the like is reacted by heat or light or the like, and the polyfunctional peroxide or the peroxide monomer is reacted. After obtaining a copolymer of a water-insoluble monomer and a water-insoluble monomer, a water-soluble monomer, a volatile solvent, a surfactant, and the like are added to the copolymer to prepare a polymerizable composition. After coating on the surface of the support, a method of curing by heating.

As the second method, a water-soluble monomer, a macromonomer having a water-insoluble polymer in a side chain,
Preparing a polymerizable composition by mixing a photopolymerization initiator, a volatile solvent, a surfactant, and the like, coating the polymerizable composition on a support, and heating or irradiating with an actinic ray. Curing method.

When the above curing reaction is carried out at room temperature by irradiation with actinic rays, the volatile solvent used is 20 ° C.
It is preferable that the saturated vapor pressure in is not less than 10 hPa and not more than 500 hPa. If it is less than 10 hPa, volatilization is too slow, so that a heating treatment and a washing treatment are required after heating, and the process becomes complicated.If it is more than 500 hPa, volatilization is too fast, and the amount of solvent during the curing reaction is too small, The curing reaction does not proceed well.

However, if the saturated vapor pressure is less than 10 hPa or 5
Even if the solvent exceeds 00 hPa, this solvent can be used as long as it is not contained as a main component in the volatile solvent solvent. When curing at a temperature lower or higher than room temperature, it is preferable to use a volatile solvent having a saturated vapor pressure according to the temperature.

The method for coating the polymerizable composition on a support is not particularly limited, and examples thereof include spray coating,
Bar coating, dipping, roll coating, spin coating, screen printing and the like can be mentioned.

The above-mentioned actinic rays used for curing include ultraviolet rays, visible rays, electron beams, radiations, etc., but ultraviolet rays are preferred because the apparatus for emitting actinic rays is simple. When using ultraviolet rays or the like, a photopolymerization initiator is mixed with the polymerizable composition. Examples of the photopolymerization initiator when using ultraviolet light include sulfides such as sodium methyldithiocarbamate sulfide, tetramethylthiuram monosulfide, diphenyl monosulfide, dibenzothiazoyl monosulfide, and disulfide; thioxanthone, ethyl thioxanthone ,
2-chlorothioxanthone, diethylthioxanthone,
Thioxanthone derivatives such as diisopropylthioxanthone; diazo compounds such as hydrazone, azoisobutyronitrile, benzenediazonium; benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzophenone, dimethylaminobenzophenone, Michler's ketone, benzylanthraquinone, t Aromatic carbonyl compounds such as -butylanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-aminoanthraquinone, 2-chloroanthraquinone, benzyldimethylketal and methylphenylglyoxylate; 1-hydroxycyclohexylphenylketone, 2-hydroxy -2-methyl-1-
Acetophenone derivatives such as phenylpropan-1-one, 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, 2,2-diethoxyacetophenone and 2,2-dimethoxyacetophenone;
-Methyl dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, butyl 4-dimethylaminobenzoate,
Dialkylaminobenzoic esters such as isopropyl 4-diethylaminobenzoate; peroxides such as benzoyl peroxide, di-t-butyl peroxide, dicumyl peroxide, cumene hydroperoxide; 9-phenylacridine, 9-p Acridine derivatives such as -methoxyphenylacridine, 9-acetylaminoacridine, benzacridine; 9,10-dimethinobenzphenazine, 9-methylbenzphenazine,
Phenazine derivatives such as methoxybenzphenazine;
Quinosaline derivatives such as 4,4 ', 4 "-trimethoxy-2,3-diphenylquinosaline; 2,4,5-triphenylimidazoyl dimer; halogenated ketones; acylphosphine oxides, acylphosphonates and the like Acylated phosphorus compounds.

Further, as the photopolymerization initiator when using visible light, for example, 2-nitrofluorene, 2,4,4
Examples thereof include 6-tris (chloromethyl) -1,3,5-triazine, 3,3′-carbonylbiscoumarin, and thiomichler ketone. The photopolymerization initiators may be used alone or in combination of two or more.

The compounding amount of the photopolymerization initiator is preferably 0.01 to 20 parts by weight based on the water-soluble monomer. 0.01
If the amount is less than 10 parts by weight, sufficient reactivity cannot be obtained, the crosslinking point is reduced, and an ink receiving layer having low water resistance is obtained. If the amount is more than 20 parts by weight, the ink receiving layer becomes brittle or easily discolored. More preferably, it is 0.1 to 5 parts by weight.

In the case of irradiating ultraviolet rays as the irradiation source of the actinic rays, examples of the ultraviolet irradiating apparatus include an ultra-high pressure mercury lamp, a high pressure mercury lamp, a metal halide lamp, a xenon lamp, and a low pressure germicidal lamp. The amount of UV irradiation varies depending on the type and amount of the water-soluble monomer.
It is preferably from 0 mJ / cm ² to ²⁰ J / cm ² .

In order to prevent polymerization inhibition by oxygen,
Irradiation with ultraviolet rays or the like may be performed in an inert gas atmosphere or in a state of being laminated with glass, transparent plastic, or the like.

The recording medium having the ink receiving layer produced by the above method is capable of absorbing ink quickly and uniformly, has water resistance, has low beading, and is most suitable as a recording medium for ink jet recording. is there.

[0070]

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

Example 1 50 parts by weight of 2-hydroxyethyl acrylate, 50 parts by weight of a macromonomer having a methyl methacrylate polymer in the side chain (AA-6 manufactured by Toagosei Co., Ltd.), and 4- (2 -Hydroxyethoxy) phenyl-
1 part by weight of (2-hydroxy-2-propyl) ketone (Darocur 2959 manufactured by Merck), 50 parts by weight of water, and sodium dodecyl sulfate (Y-
100) A photopolymerizable composition was prepared by mixing 2 parts by weight.

Next, this photopolymerizable composition was coated on a 100 μm-thick polyethylene terephthalate film (manufactured by Kuraray Co., Ltd.) using a bar coater. Next, the film coated with the photopolymerizable composition was applied for 15 m using a high-pressure mercury lamp.
The recording medium 1 was obtained by irradiating ultraviolet rays at an irradiation intensity of W / cm ² for 10 minutes to form an ink receiving layer. The dry thickness of the ink receiving layer of the obtained recording medium 1 is about 10
μm.

Example 2 50 parts by weight of methyl methacrylate, 1 part by weight of t-butylperoxyallyl carbonate, and 4- (2-hydroxyethoxy) phenyl- (2-
A mixed solution was prepared by mixing 1 part by weight of (hydroxy-2-propyl) ketone (Darocur 2959, manufactured by Merck), and the mixed solution was applied to a peelable polyester film.

Next, the film coated with the above mixed solution was irradiated with ultraviolet light at an irradiation intensity of 15 mW / cm ² for 80 minutes using a high-pressure mercury lamp to synthesize a copolymer on the film. Next, 50 parts by weight of the obtained copolymer is dissolved in 50 parts by weight of 2-hydroxyethyl acrylate, and 50 parts by weight of water and 2 parts by weight of sodium dodecyl sulfate (Y-100) as a surfactant are further added. Was added to prepare a polymerizable composition.

Next, this polymerizable composition was applied to a polyethylene terephthalate film (manufactured by Kuraray) having a thickness of 100 μm.
Was coated with a bar coater. Next, the film coated with the polymerizable composition was reacted in a constant temperature and humidity oven at 90 ° C. and a relative humidity of 80% for 10 hours to obtain a recording medium 2. The dry thickness of the ink receiving layer of the obtained recording medium 2 was about 10 μm.

Example 3 A recording medium 3 was obtained in the same manner as in Example 1, except that 50 parts by weight of glucosylethyl methacrylate was used instead of 50 parts by weight of 2-hydroxyethyl acrylate. The dry thickness of the ink receiving layer of the obtained recording medium 3 was about 10 μm.

Example 4 50 parts by weight of 2-hydroxyethyl acrylate, 50 parts by weight of a macromonomer having a polymer of methyl methacrylate in the side chain (AA-6, manufactured by Toagosei Co., Ltd.), and 1,6-hexanediol acrylate as a crosslinking agent 0.1 part by weight, 1 part by weight of 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone (Darocur 2959, manufactured by Merck) as a photopolymerization initiator, and 5 parts of water
By mixing 0 parts by weight and 2 parts by weight of sodium dodecyl sulfate (Y-100) as a surfactant,
A photopolymerizable composition was prepared.

Next, this photopolymerizable composition was coated on a 100 μm-thick polyethylene terephthalate film (manufactured by Kuraray Co., Ltd.) using a bar coater. Next, the film coated with the photopolymerizable composition was applied for 15 m using a high-pressure mercury lamp.
The recording medium 4 was obtained by irradiating ultraviolet rays at an irradiation intensity of W / cm ² for 10 minutes to form an ink receiving layer. The dry thickness of the ink receiving layer of the obtained recording medium 4 is about 10
μm.

Example 5 A recording medium 5 was obtained in the same manner as in Example 4, except that 50 parts by weight of glucosylethyl methacrylate was used instead of 50 parts by weight of 2-hydroxyethyl acrylate. The dry thickness of the ink receiving layer of the obtained recording medium 5 was about 10 μm.

Comparative Example 1 100 parts by weight of 2-hydroxyethyl acrylate, 1 part by weight of 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone (Darocur 2959, Merck) as a photopolymerization initiator Parts, and as a surfactant, sodium dodecyl sulfate (Y-100) 2
The photopolymerizable composition was prepared by mixing parts by weight. Next, the photopolymerizable composition was applied to a 100 μm-thick polyethylene terephthalate film (manufactured by Kuraray Co., Ltd.) using a bar coater.

Next, the film coated with the polymerizable composition was irradiated with ultraviolet light at an irradiation intensity of 15 mW / cm ² for 10 minutes using a high-pressure mercury lamp to form an ink receiving layer. I got The dry thickness of the ink receiving layer of the obtained recording medium 6 was about 10 μm.

The printing performance of the recording media 1 to 6 obtained in Examples 1 to 5 and Comparative Example 1 and the water resistance and beading resistance of the ink receiving layer were evaluated as follows. Table 1 shows the evaluation results.

Evaluation method (1) Printing performance Ink jet printer (BJC-42 manufactured by Canon Inc.)
0), a black letter "S" is printed on a yellow background in MS Gothic font at 20 points, and a character with almost no blur and a sharp outline is marked with "O", and a partially blurred character is marked with "△". Those that strongly bleed were marked as x.

(2) Water resistance of the ink receiving layer The recording medium before printing was immersed in distilled water at 25 ° C. for 5 minutes.
After removal, the surface was visually observed. And
も の indicates no change in the recording medium, and X indicates that the ink receiving layer began to melt, dropped off, or curled.

(3) Beading resistance Inkjet printer (BJC-42 manufactured by Canon Inc.)
In 0), a black character "S" is printed in a 20-point MS Gothic font on a yellow background, and the character which has almost no color unevenness and is uniformly colored is indicated by "O". Are evaluated as “い る”, and those having color unevenness as a whole are evaluated as “x”.

[0086]

[Table 1]

[0087]

Since the recording medium of the present invention has the above-described structure, the ink is rapidly and uniformly absorbed, has water resistance, has little beading, and is optimal as a recording medium for ink jet recording. is there.

Claims (1)

[Claims] 1. A recording medium provided with an ink receiving layer on a support, wherein the ink receiving layer is made of a block copolymer of a water-soluble monomer and a water-insoluble monomer. To be recorded.