JP2013193212A - Inkjet recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet recording material excellent in ink absorbency, free from crack generation on an image part after printing, and excellent in curling resistance, rear face cracking resistance and transparency regardless of printing by an aqueous pigment inkjet printer.SOLUTION: An inkjet recording material has an ink receiving layer (incidentally, when the ink receiving layer contains inorganic fine particles, the content of the inorganic fine particles is not more than 5 mass% relative to a total solid of the ink receiving layer) containing a cationic polyurethane resin, polyvinyl alcohol and boric acid or its salt on one surface of a non-water-absorbing support, and a layer containing resin emulsion of at least 10°C and not more than 25°C in minimum filming temperature and at least 40°C in glass transition temperature, polyvinyl alcohol, boric acid or its salt, and a water soluble polyvalent metal compound on a surface on the opposite side of the ink receiving layer as a back coating layer, a solid component coating amount of the back coating layer is at least 2 g/mand not more than 100 mass% of a solid component coating amount of the ink receiving layer.

Description

  The present invention relates to an ink jet recording material. More specifically, the ink absorption is excellent even when printing is performed with a water-based pigment ink jet printer, and the image portion is not cracked after printing, curling resistance, scratch resistance on the back surface, and transparency. The present invention relates to an ink jet recording material excellent in the above.

  The ink jet method as an image output method is widely used not only for general consumers such as photographic use but also for industrial use, and its use is expanding more and more.

  In general consumer applications, water-based inks are the mainstream, although there are differences between dye inks and pigment inks. In industrial applications, there are a wide variety of inks, and not only water-based inks but also many types such as solvent-based inks, ultraviolet curable inks, and thermosetting inks called latex inks are used.

  From the viewpoint of the weather resistance of the output image, the non-aqueous ink is generally superior to the aqueous ink. Further, there are many non-aqueous inks that solidify on the surface of the recording material and ink media that have high volatility, and there is a general merit that there are wide choices of recording materials. On the other hand, the recording material for water-based ink needs to absorb all of the ejected ink, and there are restrictions on the recording material that can be used. However, the water-based ink jet printer has a great advantage that it is very easy to operate in the work environment because it does not require a large facility such as an exhaust device necessary for the solvent ink or the like and does not particularly cause an odor problem.

  In the recording material for an aqueous ink jet recording system in which an ink receiving layer is provided on a support, the ink receiving layer is roughly classified into two types. One is a porous ink receiving layer mainly composed of an inorganic pigment and a resin binder, and the other is an ink receiving layer mainly composed of a water-soluble polymer. The former ink receiving layer absorbs ink in the voids formed by the inorganic pigment, and the latter ink receiving layer absorbs ink by swelling of the water-soluble polymer. Due to such a difference in ink absorption mechanism, the former is called a void type (or microporous type), and the latter is called a swelling type (or polymer type).

  As the inorganic pigment contained in the former porous ink-receiving layer, from the viewpoint of obtaining excellent gloss, image clarity and color developability, gas phase method silica pulverized / dispersed to an average secondary particle size of 500 nm or less, It has been proposed to use inorganic fine particles such as wet process silica, alumina, and hydrates thereof as a pigment component of the ink receiving layer.

  The latter swelling type ink-receiving layer contains various hydrophilic polymers such as gelatin, polyvinyl alcohol, polyvinylpyrrolidone, carboxymethylcellulose, hydroxymethylcellulose, hydroxypropylcellulose, cellulose derivatives such as hydroxypropylmethylcellulose, and acrylic acid-based polymers. Ink receiving layers have been proposed.

  The swelling type ink receiving layer is a continuous and uniform film, so that a high glossiness is obtained, and the ink absorption capacity is high and the amount of ink shot can be increased, so that the image density can be increased. Depending on the material used, there is an advantage that a highly transparent coating layer can be obtained and the coating layer does not break even when the recording material is bent at an acute angle, but there is a problem that the ink absorption speed and the drying speed after printing are inferior. .

  On the other hand, a void-type ink-receiving layer is preferable because of its excellent ink absorption speed and drying speed after printing. On the other hand, if an ink amount exceeding the ink absorption capacity is applied, the image is not limited to the portion where the ink is applied, and the image can be appreciated. The ink is absorbed in the voids formed by the aggregates of the inorganic fine particles constituting the ink receiving layer. If inorganic fine particles with a small particle diameter are used, the coating layer Transparency improves but ink absorbency decreases, it is difficult to achieve both high transparency and high ink absorbency of the coating layer, and the coating layer is brittle, so if the recording material is bent at an acute angle, cracks will occur There is a problem that it occurs. As described above, since the characteristics of the individual ink receiving layers are different due to the difference in the ink absorption mechanism, the ink receiving layer needs to be selectively used as a void type and a swelling type depending on the application.

  For example, a flexible packaging film, such as a PET bottle beverage label design configuration, that outputs an image on a highly transparent recording material and wraps it around an object such as a PET bottle to examine its design and appearance In such a design configuration, the swollen ink receiving layer is suitable because the printed matter may be bent at an acute angle and the recording material itself needs to be highly transparent.

  JP-A-2007-276392 (Patent Document 1), for example, discloses an inkjet receptive agent that can provide an inkjet recording material excellent in water resistance and glossiness at the same time as high inkjet aptitude, and includes a cationic polyurethane resin, secondary amines, and There has been proposed an ink jet receiving agent containing a cationic copolymer obtained by reacting an epihalohydrin. Japanese Patent Application Laid-Open No. 2007-168164 (Patent Document 2) discloses an ink jet receiving agent containing a cationic polyurethane resin, polyvinyl alcohol having a saponification degree of 70 to 90 mol%, and a water-soluble polyvalent metal salt. Proposed. Japanese Unexamined Patent Application Publication No. 2009-46780 (Patent Document 3) proposes an ink jet receiving agent containing a cationic polyurethane resin, a water-soluble magnesium salt and polyvinyl alcohol in combination. Japanese Patent Laid-Open No. 2005-74880 (Patent Document 4) discloses that an ink receiving layer is composed of a water-based urethane resin and a water-based acrylic resin, and crosslinks a polymer having an oxazoline group and an acrylic water-soluble self-emulsifying epoxy curing agent. An ink jet recording sheet contained as an agent has been proposed.

  However, when printing is performed under conditions of high temperature and humidity, depending on the combination of the recording material and the ink jet printer, the printed portion may be cracked, which is a serious problem.

  On the other hand, the curl resistance of the recording material is very important. If the curl is poor, it may come into contact with the printer head during printing, and a desired printed matter may not be obtained or the printer head may be broken.

  Some types of ink jet printers are liable to cause scratches on the back surface of the recording material during printing. When a highly transparent recording material is used, this scratch is very noticeable, which is a serious problem.

  In order to prevent curl balance and scratches as described above, it is generally well known to provide a backing layer on the back surface of the recording material. For example, JP 2007-245427 A and JP 2008-246664 A (Patent Documents 5 and 6) describe recording materials that are effective in transparency, curl resistance, show-through resistance after printing, and blocking resistance. Proposed. However, these proposals relate to a backing layer for a void type ink receiving layer, and are not easy to apply to swelling type ink receiving layers having different curling behaviors.

JP 2007-276392 A JP 2007-168164 A JP 2009-46780 A Japanese Patent Laid-Open No. 2005-74880 JP 2007-245427 A JP 2008-246664 A

  An object of the present invention is an ink jet recording material which is excellent in ink absorbency even when printed with a water-based pigment ink jet printer, and does not cause cracks in the image area after printing, and has excellent curl resistance, scratch resistance on the back surface and transparency. Is to provide.

The above object of the present invention has been achieved by the following means.
(1) An ink receiving layer containing a cationic polyurethane resin, polyvinyl alcohol and boric acid or a salt thereof on one surface of a non-water-absorbing support (however, when the ink receiving layer contains inorganic fine particles, inorganic fine particles Is 5% by mass or less based on the total solid content of the ink receiving layer), and the minimum film-forming temperature is 10 ° C. or more and 25 as a backing layer on the surface opposite to the ink receiving layer. Having a layer containing a resin emulsion having a glass transition temperature of 40 ° C. or lower, polyvinyl alcohol, boric acid or a salt thereof, and a water-soluble polyvalent metal compound, and a solid content coating amount of the backing layer Is an ink jet recording material, characterized by being 2 g / m ² or more and 100% by mass or less of the solid content coating amount of the ink receiving layer.
(2) Polyvinyl alcohol and water-soluble polyvalent metal compound are each 20 to 100% by mass of a resin emulsion having a minimum film-forming temperature of 10 ° C. or more and 25 ° C. or less and a glass transition temperature of 40 ° C. or more. 80% by mass and 1 to 8% by mass, and the content of boric acid or a salt thereof is 0.5 to 25% by mass with respect to polyvinyl alcohol in the backing layer. Inkjet recording material.

  ADVANTAGE OF THE INVENTION According to this invention, even if it prints with a water-type pigment inkjet printer, the ink recording material which is excellent in ink absorptivity and does not produce a crack in a printing part can be obtained.

Hereinafter, the ink receiving layer of the present invention will be described in detail.
The polyurethane resin is obtained by reacting a polyisocyanate and a polyol. Examples of polyisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2, 2'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dichloro-4,4'-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate Tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexane Examples include silylene diisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, triphenylmethane triisocyanate, 1-methylbenzol-2,4,6-triisocyanate. be able to. These polycyanate compounds may be used alone or in combination of two or more.

  Known polyols can be used as the polyol used for obtaining the polyurethane resin, and examples thereof include polyether polyol, polyester polyol, polycarbonate polyol, polyacetal polyol, and polyacrylate polyol. Examples of the polyether polyol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,4-propanediol, and 3-methyl-2,4. -Pentanediol, 2,4-pentanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2,4-diethyl-1,5- Pentanediol, 1,6-hexanediol, 1,7-heptanediol, 3,5-heptanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1 , 10-decanediol, aliphatic diols such as diethylene glycol and triethylene glycol, cyclohexane dimethano And alicyclic diols such as cyclohexanediol, trimethylolethane, trimethylolpropane, hexitols, pentitols, glycerin, pentaerythritol, tetramethylolpropane and other trivalent alcohols, polytetramethylene glycol, etc. Can be mentioned. Examples of the polyester polyol include ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, Diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanedimethanol, bisphenol A, bisphenol S, hydroquinone, or alkylene oxide addition of these compounds Body diol components and malonic acid, succinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, deca Dicarboxylic acid, dodecanedicarboxylic acid, hexadecanedicarboxylic acid, maleic acid, fumaric acid, 1,3-cyclopentanedicarboxylic acid, phthalic acid, terephthalic acid, isophthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, 1,2-bisphenoxyethane-p, p'-dicarboxylic acid, trimellitic acid, trimesic acid, castor oil fatty acid trimer, Polyesters obtained by condensation reaction from polycarboxylic acid components such as carboxylic acid anhydride salts or ester-forming derivatives, polyesters obtained by ring-opening polymerization reaction of cyclic ester compounds such as ε-caprolactone, and copolymers thereof Examples include polyesters.

  The polyurethane resin used in the present invention needs to be cationic from the viewpoint of ink fixing properties, and known cationic polyurethane resins can be used. As a method for introducing a cationic group into a polyurethane resin, for example, a method of neutralizing a tertiary amino group of a polyamine used as a chain extender described later with an acid or quaternizing with a quaternizing agent, As described in JP 2007-168164 A, a polyol containing a tertiary amino group in the side chain is used, and the tertiary amino group is neutralized with an acid or quaternized with a quaternizing agent to be cationized. Methods and the like. When using a polyol containing a tertiary amino group in the side chain, other polyols containing no tertiary amino group may be used together. Examples of acids that can be used for neutralizing the tertiary amino group include formic acid, acetic acid, propionic acid, succinic acid, glutaric acid, butyric acid, lactic acid, malic acid, citric acid, tartaric acid, and malonic acid. Organic acids such as adipic acid, sulfonic acids, p-toluenesulfonic acid, methanesulfonic acid, hydroxymethanesulfonic acid and other organic sulfonic acids, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, boric acid, phosphorous acid, hydrofluoric acid, etc. An inorganic acid etc. are mentioned, You may use these individually or in combination of 2 or more types. Examples of the quaternizing agent that can be used for quaternizing the tertiary amino group include dialkyl sulfates such as dimethyl sulfate and diethyl sulfate, methyl chloride, ethyl chloride, benzyl chloride, Alkyl halides such as methyl bromide, ethyl bromide, benzyl bromide, methyl iodide, ethyl iodide, benzyl iodide, etc., alkyl such as methyl methanesulfonate, methyl paratoluenesulfonate, or methyl arylsulfonates, ethylene oxide, Epoxys such as propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, allyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, and phenyl glycidyl ether It is.

  Examples of the chain extender used for the purpose of adjusting physical properties such as mechanical properties and thermal properties of the polyurethane resin include polyamines and chain extenders containing active hydrogen. Examples of the chain extender for polyamines include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4'-dicyclohexylmethanediamine, 3 , 3'-dimethyl-4,4'-dicyclohexylmethanediamine, 1,4-cyclohexanediamine, hydroxymethylaminoethylamine, hydroxyethylaminoethylamine, hydroxypropylaminopropylamine, ethylaminoethylamine, methylaminopropylamine, diethylenetriamine, di Diamines such as propylene triamine and triethylenetetramine, hydrazines such as hydrazine, N, N'-dimethylhydrazine, 1,6-hexamethylenebishydrazine, and succinic acid Dihydrazides such as hydrazide, adipic acid dihydrazide, glutaric acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide, β-semicarbazide propionic acid hydrazide, 3-semicarbazide-propyl-carbazic acid ester, semicarbazide-3-semicarbazide methyl-3,5 Semicarbazides such as 5-trimethylcyclohexane are exemplified. As chain extenders containing active hydrogen, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, saccharose, methylene Glycols such as glycol, glycerin, sorbitol, bisphenol A, 4,4′-dihydroxydiphenyl, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenylsulfone, hydrogenated bisphenol A, phenols such as hydroquinone and water Can be mentioned.

  A known method can be used for the method for producing the cationic polyurethane resin in the present invention. For example, a batch reaction method in which raw materials such as polyisocyanate and polyol are charged and reacted together and a sequential reaction method in which a part of the raw materials such as polyisocyanate and polyol are charged and reacted are included.

  The cationic polyurethane resin used in the present invention is, for example, from DIC Corporation as Pateracol series, from Ohara Palladium Chemical Co., Ltd. as Parasurf UP-28, UP-36, from Meisei Chemical Industry Co., Ltd. What is marketed as JK-830 etc. can also be obtained and utilized.

Although there is no restriction | limiting in particular in the solid content coating amount of the cationic polyurethane resin used for this invention, 5-40 g / m < ² > is preferable and 7-35 g / m < ² > is especially preferable. If it is 5 g / m ² or less, the ink absorbability may be lowered, and if it is more than 40 g / m ² , the cost may be increased, or the curling property and transparency may be deteriorated.

  The polyvinyl alcohol contained in the ink receiving layer is preferably completely or partially saponified, and preferably has a saponification rate of 70% or more. The average degree of polymerization is preferably from 200 to 5,000. Further, modified polyvinyl alcohol such as cation-modified polyvinyl alcohol can also be used. For example, as described in JP-A-61-10383, a primary to tertiary amino group or a quaternary ammonium group can be used as polyvinyl alcohol. This is polyvinyl alcohol or the like contained in the main chain or side chain. The amount of polyvinyl alcohol added in the present invention is preferably 10 to 90% by mass, particularly preferably 18 to 75% by mass, based on the polyurethane resin. The ink receiving layer of the present invention may be formed by mixing the above-mentioned cationic polyurethane resin and polyvinyl alcohol to prepare a coating solution and coating it. For example, Pateracol EG-4X (DIC Corporation) ) And Parasurf UP-28 (produced by Ohara Palladium Chemical Co., Ltd.) are premixed with a cationic polyurethane resin and polyvinyl alcohol. Moreover, polyvinyl alcohol and a cationic polyurethane resin can also be added and used with respect to these commercial items.

  The reason why cracks occur in the printed portion when an image is output using the pigment ink on the swelling type recording material is presumed as follows. The solvent component in the ink is absorbed by the swelling of the polymer in the swelling type ink receiving layer. When the solvent component in the ink is released in the subsequent drying process, the ink receiving layer contracts. On the other hand, the pigment colorant in the ink printed and separated from the solvent component stays on the surface of the ink receiving layer to form an image. Since the ink pigment does not particularly absorb the solvent component by swelling, the volume does not change in the process from printing to drying. Thus, it is considered that cracking occurs due to the difference in expansion / contraction ratio between the image portion and the ink receiving layer. Further, if the swelling of the ink receiving layer is suppressed in order to reduce the expansion and contraction of the ink receiving layer, the ink absorbability is lowered and the adjustment is very difficult.

  There are many cross-linking agents for polyvinyl alcohol. For example, zirconium compounds such as boric acid and its salts, zirconium acetate, zirconium chloride, zirconium chloride octahydrate, hydroxy zirconium chloride, water soluble organic titanium compounds such as titanium lactate, epoxy compounds, methylol melamine, glyoxal, etc. Organic crosslinking agents and the like are known.

  Examples of boric acid or a salt thereof used in the present invention include orthoboric acid, metaboric acid, diboric acid, tetraboric acid, pentaboric acid, octaboric acid, borax and the like, and these are used alone or in combination of two or more. May be. It is considered that the crosslinking of the polyvinyl alcohol in the ink receiving layer can moderately suppress the swelling of the cationic polyurethane resin and suppress the cracking of the printed portion. In view of the mechanism, it is preferable that boric acid or a salt thereof is contained more in a portion farthest from the support of the ink receiving layer. If boric acid or a salt thereof is uniformly present in the ink receiving layer, it may be difficult to achieve both ink absorbency and suppression of cracks in the image area. A preferable addition amount of boric acid or a salt thereof is 15 to 65% by mass with respect to polyvinyl alcohol in the ink receiving layer containing boric acid or a salt thereof, and 20 to 60% by mass is particularly preferable. If the amount added is too large, the ink absorbency is lowered, and if it is too small, the effect of suppressing cracking is lowered.

  In the present invention, as a method for making boric acid or a salt thereof more present in a portion farthest from the support in the ink receiving layer, 1) two or more ink receiving layers containing a cationic polyurethane resin and polyvinyl alcohol are provided, Any method of adding boric acid or a salt thereof to the ink-receiving layer coating solution furthest from the support and 2) applying boric acid or a salt thereof from above the ink-receiving layer coating solution may be used. In the case of the above 1), a layer containing a combination of a cationic polyurethane resin and polyvinyl alcohol in order from the side closer to the support, and a layer containing a combination of a cationic polyurethane resin, polyvinyl alcohol and boric acid or a salt thereof, Are preferably applied sequentially or in multiple layers. In the present invention, sequential coating is one form of a multi-layer coating method, in which an ink receiving layer on the side close to the support is coated and dried, and then an ink receiving layer is further coated thereon and dried. means. In the present invention, the multilayer coating means a multi-layer coating method in which an ink receiving layer is further coated before being dried after the ink receiving layer on the side close to the support is coated. The multi-layer coating in the present invention includes a so-called wet on wet method in which each layer is individually coated, and a multi-layer simultaneous coating method in which all layers are simultaneously coated using a slide bead method or the like. The timing of applying the upper layer by the wet on wet method may be any of the constant rate drying region and the reduced rate drying region immediately after the lower layer application. In the case of 2), it is desirable to apply boric acid or a salt thereof after applying a layer containing a combination of a cationic polyurethane resin and polyvinyl alcohol. It is desirable to apply boric acid or a salt thereof by applying a solution in which the boric acid or a salt thereof is dissolved onto the ink receiving layer or spraying it with a spray or the like. The timing of applying boric acid or a salt thereof may be after the ink receiving layer coating solution is dried, or may be an undried state in which the ink receiving layer coating solution is wet. Further, when the ink receiving layer coating liquid is undried, it may be in any of the constant rate drying region and the reduction rate drying region immediately after application of the ink receiving layer coating solution.

  The ink receiving layer of the present invention may contain a water-soluble polyvalent metal compound for the purpose of improving the fixability of the pigment ink and adjusting the ink absorbability. Water-soluble aluminum compounds and water-soluble zirconium compounds can be preferably used as the water-soluble polyvalent metal compound effective for improving the fixability of the pigment ink.

  Examples of water-soluble zirconium compounds that can be used in the ink receiving layer of the present invention include zirconium acetate, zirconium nitrate, basic zirconium carbonate, zirconium hydroxide, zirconium carbonate / ammonium, zirconium carbonate / potassium, zirconium sulfate, zirconium fluoride, Zirconium chloride, zirconium chloride octahydrate, zirconium oxychloride, hydroxyzirconium chloride and the like can be mentioned. Among these water-soluble zirconium compounds, zirconium acetate (zirconyl acetate) and zirconium oxychloride are particularly preferable.

  As the water-soluble aluminum compound, for example, as the inorganic salt, aluminum chloride or its hydrate, aluminum sulfate or its hydrate, ammonium alum and the like are known. Furthermore, a basic polyaluminum hydroxide compound which is an inorganic aluminum-containing cationic polymer is known.

Among these water-soluble aluminum compounds, those that can be stably added to the coating solution for forming the ink receiving layer are preferable, and a basic polyaluminum hydroxide compound is preferably used. The main component of this compound is represented by the following formula 1, 2 or 3, for example, [Al ₆ (OH) ₁₅ ] ³⁺ , [Al ₈ (OH) ₂₀ ] ⁴⁺ , [Al ₁₃ (OH) ₃₄ ] ⁵⁺ , It is a water-soluble polyaluminum hydroxide that stably contains a basic and high-molecular polynuclear condensed ion such as [Al ₂₁ (OH) ₆₀ ] ³⁺ .

[Al ₂ (OH) _n Cl _6-n ] _m ·· Formula 1
[Al (OH) ₃ ] _n AlCl ₃ .. Formula 2
Al _n (OH) _m Cl _(3n−m) 0 <m <3n Formula 3

  These are water treatment agents in the name of polyaluminum chloride (PAC) from Taki Chemical Co., Ltd., in the name of polyaluminum hydroxide (Paho) from Asada Chemical Industry Co., Ltd., and Riken Co., Ltd. It is commercially available from Green under the name of Purachem WT and from other manufacturers for the same purpose, and various grades are readily available. In the present invention, these commercially available products can be used as they are.

  The purpose of adjusting the ink absorptivity is to moderately inhibit hydrogen bonding of the polyvinyl alcohol used in the present invention. If hydrogen bonding of polyvinyl alcohol occurs too much, the ink absorbability may be deteriorated. On the other hand, if the hydrogen bond is inhibited too much, crosslinking by boric acid or its salt of polyvinyl alcohol hardly occurs, and there is a possibility that an image portion will be cracked after printing. Examples of water-soluble polyvalent metal compounds preferably used for this purpose include divalent metal salts such as magnesium salts, calcium salts, barium salts, iron (II) salts, copper (II) salts, zinc salts, and aluminum salts. Trivalent metal salts such as chromium salts can be used, and among them, magnesium salts such as magnesium chloride, magnesium acetate, magnesium nitrate, and magnesium sulfate are preferably used. Among these, magnesium chloride is more preferably used.

  The content of the water-soluble polyvalent metal compound is preferably in the range of 0.1 to 12% by mass with respect to the solid coating amount of the ink receiving layer.

  The ink receiving layer of the present invention has various hydrophilic properties such as gelatin, polyvinyl pyrrolidone, carboxymethyl cellulose, hydroxymethyl cellulose, hydroxypropyl cellulose, hydroxypropyl cellulose, cellulose derivatives such as hydroxypropyl methylcellulose, and acrylic polymers for the purpose of improving ink absorbability. The polymer can be added as long as cracks do not occur.

  The ink receiving layer further comprises a coloring dye, a coloring pigment, an ultraviolet absorber, an antioxidant, a crosslinking agent, an antifoaming agent, a leveling agent, a surfactant, an antiseptic, a fluorescent brightening agent, a viscosity stabilizer, a pH adjusting agent, Various known additives such as a matting agent can also be added.

  The ink receiving layer of the present invention preferably does not contain an inorganic pigment from the viewpoints of folding resistance and transparency of the coating layer. The inorganic pigment can be added as required, such as a matting agent, but the amount added must be 5% by mass or less based on the solid content of the ink receiving layer. The transparency of the coating layer can be determined by applying an ink receiving layer to a transparent film base and measuring the haze of the obtained recording material with a haze meter or the like. When the haze value is 5% or less, the coating layer is considered to be transparent.

  As a method for applying the ink receiving layer of the present invention, any method such as a blade coater, an air knife coater, a roll coater, a bar coater, a gravure coater, a reverse coater, a slide bead coater, and a slide curtain coater may be used. When two or more layers such as an ink receiving layer and other layers are provided, a multilayer coating method using a slide bead coater or a slide curtain coater is preferably used.

  Examples of the non-absorbent support of the ink jet recording material of the present invention include resin-coated paper and resin film in which at least one surface of the base paper is coated with a resin, and a resin film having a haze of 6% or less is preferable. The thickness of these supports is 15 to 350 μm, preferably 20 to 300 μm.

  Next, the backing layer of the present invention will be described in detail. The backing layer of the present invention is on the surface opposite to the ink receiving layer and the support of the ink jet recording material, and affects the curl resistance, scratch resistance and transparency.

  As described above, the curl resistance is intended to prevent contact with the printer head during printing, preventing a desired printed matter from being obtained or destroying the printer head. It is also important from the viewpoint of appearance when appreciating the output. In order to prevent head rubbing in the printer, for example, when an A4 size cut sheet is used, the height of warping at the four corners needs to be 5 mm or less on the ink receiving layer side and 15 mm or less on the backing layer side. The appearance during viewing is preferably 3 mm or less on the ink receiving layer side and 10 mm or less on the backing layer side.

The backing layer of the present invention contains a resin emulsion having a minimum film forming temperature of 10 ° C. or higher and 25 ° C. or lower and a glass transition temperature of 40 ° C. or higher. In general, the resin emulsion refers to a property in which resin fine particles are colloidally dispersed in a liquid medium. In the present invention, “containing a resin emulsion in the backing layer” means that the resin emulsion is contained in the backing layer. It means that the resin component derived from is included. The resin emulsion not only acts as a binder for the backing layer, but also improves scratch resistance. If the minimum film-forming temperature of the resin emulsion exceeds 25 ° C., it is difficult to form a film during coating and drying of the backing layer, and the strength of the coating layer is reduced, so that it cannot be used. If the minimum film-forming temperature is lower than 10 ° C., the backing layer tends to be sticky and cannot be used. If the glass transition temperature of the resin emulsion is lower than 40 ° C., the strength of the backing layer is lowered, and the resin emulsion cannot be used because it is easily damaged during transportation. There is no particular limitation on the upper limit of the glass transition temperature. The coating amount of the resin emulsion having a minimum film forming temperature of 10 ° C. or more and 25 ° C. or less used for the backing layer of the present invention and a glass transition temperature of 40 ° C. or more is preferably ² to 7 g / m ² . If the coating amount is too small, the effect of scratch resistance is reduced. If the coating amount is too large, uniform coating may be difficult.

  The polyvinyl alcohol used for the backing layer of the present invention is contained for adjusting the curling property, and is preferably completely or partially saponified, and preferably has a saponification rate of 70% or more. The average degree of polymerization is preferably from 200 to 5,000. In addition, modified polyvinyl alcohol such as cation-modified polyvinyl alcohol can also be used. The content of polyvinyl alcohol in the backing layer of the present invention is preferably 20 to 80% by mass with respect to a resin emulsion having a minimum film-forming temperature of 10 ° C. or more and 25 ° C. or less and a glass transition temperature of 40 ° C. or more. 25-55 mass% is especially preferable. When the content ratio with respect to the resin emulsion is too small, the curl adjusting ability is lowered. This is presumed to be because moisture absorption and release is less likely to occur because polyvinyl alcohol is coated with the resin emulsion. When the content ratio of polyvinyl alcohol is too large, the scratch resistance of the backing layer is lowered.

  Examples of boric acid or a salt thereof used in the backing layer of the present invention include orthoboric acid, metaboric acid, diboric acid, tetraboric acid, pentaboric acid, octaboric acid, borax, and the like. You may use together. The content of boric acid or a salt thereof in the backing layer of the present invention is preferably 0.5 to 25% by mass, more preferably 3 to 20% by mass with respect to the content of polyvinyl alcohol in the backing layer. When the amount is less than 0.5% by mass, the effect of crosslinking polyvinyl alcohol becomes poor. On the other hand, if it exceeds 25% by mass, the scratch resistance of the backing layer is lowered although the mechanism is unknown.

  The water-soluble polyvalent metal compound used for the backing layer of the present invention is intended to moderately inhibit hydrogen bonding of polyvinyl alcohol. Examples of water-soluble polyvalent metal compounds that can be used for this purpose include divalent metal salts such as magnesium salts, calcium salts, barium salts, iron (II) salts, copper (II) salts, zinc salts, and aluminum. Trivalent metal salts such as salts and chromium salts can be used, and among them, magnesium salts such as magnesium chloride, magnesium acetate, magnesium nitrate, and magnesium sulfate are preferably used. The preferable content of the water-soluble polyvalent metal compound in the undercoat layer of the present invention is such that the minimum film-forming temperature is 10 ° C. or more and 25 ° C. or less and the glass transition temperature is 40 ° C. as a metal salt excluding hydrated water. It is 0.5-4 mass% with respect to the resin emulsion which is the above. If the amount is less than 0.5% by mass, the effect of the water-soluble polyvalent metal compound is poor. If the amount is more than 4% by mass, the coating layer may become sticky or the transparency may be lowered.

The solid coating amount of the backing layer of the present invention is 2 g / m ² or more and 100% by mass or less of the solid coating amount of the ink receiving layer. If it is less than 2 g / m ² , the effect of scratch resistance will not appear. Further, when it exceeds 100% by mass of the solid content coating amount of the ink receiving layer, the curling resistance is lowered.

  The backing layer of the present invention further comprises a coloring dye, a coloring pigment, an ultraviolet absorber, an antioxidant, a crosslinking agent, an antifoaming agent, a leveling agent, a surfactant, an antiseptic, a fluorescent whitening agent, a viscosity stabilizer, pH. Various known additives such as a regulator and a matting agent can also be added.

  As a method for applying the backing layer of the present invention, any method such as a blade coater, an air knife coater, a roll coater, a bar coater, a gravure coater, a reverse coater, a slide bead coater, a slide curtain coater, etc. may be used.

  The timing of applying the backing layer of the present invention may be before or after applying the ink receiving layer. Alternatively, the ink receiving layer and the backing layer may be applied by a tandem method in which the ink receiving layer and the backing layer are applied in one step.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, the content of this invention is not limited to an Example. Unless otherwise specified, parts and% indicate parts by mass and mass% in solid content.

(Recording material 1)
A backcoat layer coating solution 1 having the following composition was prepared. Then, after coating with a slide bead coater on a polyethylene terephthalate support having a film thickness of 100 μm and a haze of 2.8% so that the solid coating amount of the backing layer coating solution 1 is 5 g / m ² , 50 A backing coated substrate 1 was obtained by blowing air at a temperature of 0 ° C. and drying.

<Backcoat layer coating solution 1>
100 parts of Rikabond FK-610 (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 15 ° C, glass transition temperature 46 ° C)
Polyvinyl alcohol (degree of saponification 88% degree of polymerization 3500) 33 parts boric acid 2 parts magnesium chloride hexahydrate 4 parts (1.9 parts as a metal salt)
Spherical silica matting agent (average particle size 10 μm) 1.4 parts nonionic surfactant 3.7 parts The water was adjusted so that the solid content concentration was 9.6%.

Next, an ink receiving layer coating liquid 1 having the following composition is prepared, and the solid content coating amount of the ink receiving layer coating liquid 1 is 15 g / m ² on the side opposite to the back coating surface of the back-coated support 1. The recording material 1 was obtained by applying a 50 ° C. wind and drying it.

<Ink-receiving layer coating solution 1>
Pateracol EG-4X 100 parts (cationic polyurethane: polyvinyl alcohol: magnesium chloride = 100: 57: 3.1)
Boric acid 9 parts Spherical silica matting agent (average particle size 20 μm) 0.4 parts ethyl alcohol 5% based on coating liquid mass
It adjusted with water so that solid content concentration might be 11%.

(Recording material 2)
The ink receiving layer coating liquid 2 having the following composition in the order from the side closer to the support on the opposite side of the back coated surface 1 of the backing coated substrate 1 used in the recording material 1, and then the ink receiving layer coating liquid used in the recording material 1 after 1 solid coating amount is multi-layer coating by a slide bead coater such that each becomes 12.5 g / m ² and 2.5 g / m ^2, to obtain a recording material 2 was dried by blowing 50 ° C. wind .

<Ink-receiving layer coating solution 2>
Pateracol EG-4X 100 parts ethyl alcohol 5% to the coating liquid mass
It adjusted with water so that solid content concentration might be 12%.

(Recording material 3)
A recording material 3 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was not applied.

(Recording material 4)
In the recording material 2, the recording material 4 was obtained in the same manner as the recording material 2 except that the solid coating amount of the backing layer coating solution 1 was changed to 1 g / m ² .

(Recording material 5)
In the recording material 2, the recording material 5 was obtained in the same manner as the recording material 2 except that the solid coating amount of the backing layer coating solution 1 was changed to 3 g / m ² .

(Recording material 6)
In the recording material 2, the recording material 6 was obtained in the same manner as the recording material 2 except that the coating amount of the solid content of the backing layer coating liquid 1 was changed to 7 g / m ² .

(Recording material 7)
In the recording material 2, the recording material 7 was obtained in the same manner as the recording material 2 except that the solid coating amount of the backing layer coating solution 1 was changed to 13 g / m ² .

(Recording material 8)
In the recording material 2, the recording material 8 was obtained in the same manner as the recording material 2 except that the solid coating amount of the backing layer coating solution 1 was changed to 18 g / m ² .

  The obtained recording material was printed and evaluated by a water-based pigment ink printer MAXART PX-W8000 manufactured by Seiko Epson Corporation. In the evaluation, first, an ICC profile of the recording material 1 obtained using RIP manufactured by EFI was created.

  Then, using the obtained ICC profile, after drawing an image with colored ink, “white in color”, C, M, Y, Bk, R, G, B C + W (white ink), M + W, Y + W, Bk + W, R + W, G + W, and B + W solid images were output.

<Evaluation of ink absorbency>
Using the ICC profile for the recording material 1, the image was output and whether or not the ink overflowed was visually confirmed and evaluated according to the following criteria.
◎: No ink overflow ○: Slight mottling is observed at R + W, G + W, B + W, but there is no practical problem △: Mottling is clearly seen at R + W, G + W, B + W ×: Colored ink + white Mottling is seen in the ink part and ink absorbency is not good

<Evaluation of cracks in the printed part>
The above image was scanned at 23 ° C. and 50% H. At 50 ° C. and 80% R.O. within 2 minutes after printing. H. For 1 hour in the atmosphere. Then 23 ° C. 50% R.D. H. And dried for 24 hours, visually observed for cracks in the image area, and evaluated according to the following criteria.
○: No cracks in the image area ×: Even slight cracks in the image area

<Measurement of curl>
The recording material cut to A4 size is placed on a horizontal plate, seasoned for 8 hours in a specified temperature and humidity environment, and the height of the four corners is measured in mm. The value of was the curl value. When the ink receiving layer side of the recording material is warped upward, the value is expressed as a positive value, and when the backing layer side is upward, the value is warped upward. The value was expressed as a negative value. The temperature and humidity environment was measured under three conditions of 23 ° C. 25%, 23 ° C. 50%, and 23 ° C. 75%.
○: Any temperature / humidity environment was within the range of +3 mm to −10 mm. Δ: Practical use within the range of +3 mm to −10 mm and within the range of +5 mm to −15 mm in one or more temperature / humidity environments. It was an acceptable level.
X: A curl value exceeding the range of +5 mm to -15 mm was measured in one or more temperature and humidity environments.

<Scratch resistance on the back>
After printing with a water-based pigment ink printer MAXART PX-W8000 manufactured by Seiko Epson Corporation, the back surface was visually observed and judged according to the following criteria.
◎: Good with no transport scratches ○: Slightly transported scratches are attached, but it can be used because it is not conspicuous from the front surface △: There are many light transport scratches, and problems ×: Clear transport scratches are attached Unbearable

<Measurement of haze>
The haze of the recording material obtained using a haze computer HZ-2 manufactured by Suga Test Instruments Co., Ltd. was measured.

  In the recording material 8, the coating layer was disturbed when the backing layer was applied. Therefore, it is thought that transparency was lowered.

(Recording material 9)
In the recording material 2, a recording material 9 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to the backing layer coating solution 2 having the following composition.

<Backcoat layer coating solution 2>
100 parts of Rikabond ES-85 (Acrylic resin emulsion manufactured by Chuo Rika Kogyo Co., Ltd., minimum film-forming temperature 20 ° C., glass transition temperature 45 ° C.)
Polyvinyl alcohol (degree of saponification 88% degree of polymerization 3500) 33 parts boric acid 2 parts magnesium chloride hexahydrate 4 parts spherical silica matting agent (average particle size 10 μm) 1.4 parts nonionic surfactant 3.7 parts solids The concentration was adjusted with water so that the concentration was 9.6%.

(Recording material 10)
In the recording material 2, the recording material 10 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to the backing layer coating solution 3 having the following composition.

<Backcoat layer coating solution 3>
Rikabond SA-204 100 parts (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 0 ° C, glass transition temperature 41 ° C)
Polyvinyl alcohol (degree of saponification 88% degree of polymerization 3500) 33 parts boric acid 2 parts magnesium chloride hexahydrate 4 parts spherical silica matting agent (average particle size 10 μm) 1.4 parts nonionic surfactant 3.7 parts solids The concentration was adjusted with water so that the concentration was 9.6%.

(Recording material 11)
In the recording material 2, a recording material 11 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to the backing layer coating solution 4 having the following composition.

<Backcoat layer coating solution 4>
100 parts of Vinyblan 2685 (acrylic resin emulsion manufactured by Nissin Chemical Industry Co., Ltd., minimum film-forming temperature 38 ° C., glass transition temperature 50 ° C.)
Polyvinyl alcohol (degree of saponification 88% degree of polymerization 3500) 33 parts boric acid 2 parts magnesium chloride hexahydrate 4 parts spherical silica matting agent (average particle size 10 μm) 1.4 parts nonionic surfactant 3.7 parts solids The concentration was adjusted with water so that the concentration was 9.6%.

  The recording materials 9 to 11 obtained above were evaluated in the same manner as in the evaluation method in Table 1, and the results are summarized in Table 2.

(Recording material 12)
In the recording material 2, a recording material 12 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to a backing layer coating solution 5 having the following composition.

<Backcoat layer coating solution 5>
100 parts of Rikabond FK-610 (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 15 ° C, glass transition temperature 46 ° C)
Boric acid 2 parts Magnesium chloride hexahydrate 4 parts Spherical silica matting agent (average particle size 10 μm) 1.4 parts Nonionic surfactant 3.7 parts Adjusted with water to a solid content concentration of 9.6% did.

(Recording material 13)
In the recording material 2, a recording material 13 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to a backing layer coating solution 6 having the following composition.

<Backcoat layer coating solution 6>
100 parts of Rikabond FK-610 (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 15 ° C, glass transition temperature 46 ° C)
Polyvinyl alcohol (degree of saponification 88% degree of polymerization 3500) 15 parts Boric acid 0.9 parts Magnesium chloride hexahydrate 4 parts Spherical silica matting agent (average particle size 10 μm) 1.4 parts Nonionic surfactant 3.7 parts It adjusted with water so that solid content concentration might be 9.6%.

(Recording material 14)
In the recording material 2, a recording material 14 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to a backing layer coating solution 7 having the following composition.

<Backcoat layer coating solution 7>
100 parts of Rikabond FK-610 (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 15 ° C, glass transition temperature 46 ° C)
Polyvinyl alcohol (degree of saponification 88% degree of polymerization 3500) 23 parts boric acid 1.4 parts magnesium chloride hexahydrate 4 parts spherical silica matting agent (average particle size 10 μm) 1.4 parts nonionic surfactant 3.7 parts It adjusted with water so that solid content concentration might be 9.6%.

(Recording material 15)
In the recording material 2, a recording material 15 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to a backing layer coating solution 8 having the following composition.

<Backcoat layer coating solution 8>
100 parts of Rikabond FK-610 (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 15 ° C, glass transition temperature 46 ° C)
Polyvinyl alcohol (degree of saponification 88% degree of polymerization 3500) 70 parts boric acid 4.2 parts magnesium chloride hexahydrate 4 parts spherical silica matting agent (average particle size 10 μm) 1.4 parts nonionic surfactant 3.7 parts It adjusted with water so that solid content concentration might be 9.6%.

(Recording material 16)
In the recording material 2, a recording material 16 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to a backing layer coating solution 9 having the following composition.

<Backcoat layer coating solution 9>
100 parts of Rikabond FK-610 (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 15 ° C, glass transition temperature 46 ° C)
Polyvinyl alcohol (degree of saponification 88% degree of polymerization 3500) 100 parts Boric acid 6.1 parts Magnesium chloride hexahydrate 4 parts Spherical silica matting agent (average particle size 10 μm) 1.4 parts Nonionic surfactant 3.7 parts It adjusted with water so that solid content concentration might be 8.4%.

(Recording material 17)
In the recording material 2, a recording material 17 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to the backing layer coating solution 10 having the following composition.

<Backcoat layer coating solution 10>
100 parts of Rikabond FK-610 (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 15 ° C, glass transition temperature 46 ° C)
Polyvinyl alcohol (degree of saponification 88% degree of polymerization 3500) 33 parts Magnesium chloride hexahydrate 4 parts Spherical silica matting agent (average particle size 10 μm) 1.4 parts Nonionic surfactant 3.7 parts Solid content concentration 9 Adjusted with water to 6%.

(Recording material 18)
In the recording material 2, a recording material 18 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to the backing layer coating solution 11 having the following composition.

<Backcoat layer coating solution 11>
100 parts of Rikabond FK-610 (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 15 ° C, glass transition temperature 46 ° C)
Polyvinyl alcohol (degree of saponification 88% degree of polymerization 3500) 33 parts Boric acid 0.2 parts Magnesium chloride hexahydrate 4 parts Spherical silica matting agent (average particle size 10 μm) 1.4 parts Nonionic surfactant 3.7 parts It adjusted with water so that solid content concentration might be 9.6%.

(Recording material 19)
In the recording material 2, a recording material 19 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to a backing layer coating solution 12 having the following composition.

<Liquid coating liquid 12>
100 parts of Rikabond FK-610 (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 15 ° C, glass transition temperature 46 ° C)
Polyvinyl alcohol (degree of saponification 88% degree of polymerization 3500) 33 parts Boric acid 0.8 parts Magnesium chloride hexahydrate 4 parts Spherical silica matting agent (average particle size 10 μm) 1.4 parts Nonionic surfactant 3.7 parts It adjusted with water so that solid content concentration might be 9.6%.

(Recording material 20)
In the recording material 2, a recording material 20 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to the backing layer coating solution 13 having the following composition.

<Backcoat layer coating solution 13>
100 parts of Rikabond FK-610 (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 15 ° C, glass transition temperature 46 ° C)
Polyvinyl alcohol (degree of saponification 88% degree of polymerization 3500) 33 parts boric acid 4 parts magnesium chloride hexahydrate 4 parts spherical silica matting agent (average particle size 10 μm) 1.4 parts nonionic surfactant 3.7 parts solids The concentration was adjusted with water so that the concentration was 9.6%.

(Recording material 21)
In the recording material 2, a recording material 21 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to the backing layer coating solution 14 having the following composition.

<Backcoat layer coating solution 14>
100 parts of Rikabond FK-610 (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 15 ° C, glass transition temperature 46 ° C)
Polyvinyl alcohol (degree of saponification 88% degree of polymerization 3500) 33 parts Boric acid 7.5 parts Magnesium chloride hexahydrate 4 parts Spherical silica matting agent (average particle size 10 μm) 1.4 parts Nonionic surfactant 3.7 parts It adjusted with water so that solid content concentration might be 9.6%.

(Recording material 22)
In the recording material 2, a recording material 22 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to a backing layer coating solution 15 having the following composition.

<Backcoat layer coating solution 15>
100 parts of Rikabond FK-610 (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 15 ° C, glass transition temperature 46 ° C)
Polyvinyl alcohol (degree of saponification 88% degree of polymerization 3500) 33 parts boric acid 10 parts magnesium chloride hexahydrate 4 parts spherical silica matting agent (average particle size 10 μm) 1.4 parts nonionic surfactant 3.7 parts solids The concentration was adjusted with water so that the concentration was 9.6%.

(Recording material 23)
In the recording material 2, a recording material 23 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to the backing layer coating solution 16 having the following composition.

<Backcoat layer coating solution 16>
100 parts of Rikabond FK-610 (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 15 ° C, glass transition temperature 46 ° C)
Polyvinyl alcohol (degree of saponification 88% degree of polymerization 3500) 33 parts boric acid 2 parts spherical silica matting agent (average particle size 10 μm) 1.4 parts nonionic surfactant 3.7 parts solids concentration 9.6% So that it was adjusted with water.

(Recording material 24)
In the recording material 2, a recording material 24 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to a backing layer coating solution 17 having the following composition.

<Backcoat layer coating solution 17>
100 parts of Rikabond FK-610 (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 15 ° C, glass transition temperature 46 ° C)
Polyvinyl alcohol (saponification degree 88% polymerization degree 3500) 33 parts boric acid 2 parts magnesium chloride hexahydrate 2 parts (0.9 parts as a metal salt)
Spherical silica matting agent (average particle size 10 μm) 1.4 parts nonionic surfactant 3.7 parts The water was adjusted so that the solid content concentration was 9.6%.

(Recording material 25)
In the recording material 2, a recording material 25 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to a backing layer coating solution 18 having the following composition.

<Backcoat layer coating solution 18>
100 parts of Rikabond FK-610 (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 15 ° C, glass transition temperature 46 ° C)
Polyvinyl alcohol (saponification degree 88% polymerization degree 3500) 33 parts boric acid 2 parts magnesium chloride hexahydrate 6 parts (2.8 parts as a metal salt)
Spherical silica matting agent (average particle size 10 μm) 1.4 parts nonionic surfactant 3.7 parts The water was adjusted so that the solid content concentration was 9.6%.

(Recording material 26)
In the recording material 2, a recording material 26 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to a backing layer coating solution 19 having the following composition.

<Backcoat layer coating solution 19>
100 parts of Rikabond FK-610 (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 15 ° C, glass transition temperature 46 ° C)
Polyvinyl alcohol (degree of saponification 88% degree of polymerization 3500) 33 parts Boric acid 2 parts Magnesium chloride hexahydrate 12 parts (5.6 parts as metal salt)
Spherical silica matting agent (average particle size 10 μm) 1.4 parts nonionic surfactant 3.7 parts The water was adjusted so that the solid content concentration was 9.6%.

  The recording materials 12 to 26 obtained above were evaluated in the same manner as in the evaluation method in Table 1, and the results are summarized in Table 3.

(Recording material 27)
In the recording material 2, a recording material 27 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to the backing layer coating solution 20 having the following composition.

<Backcoat layer coating solution 20>
100 parts of Rikabond FK-610 (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 15 ° C, glass transition temperature 46 ° C)
Polyvinyl alcohol (degree of saponification 88% degree of polymerization 3500) 33 parts Boric acid 2 parts Magnesium chloride tetrahydrate 4.9 parts (1.9 parts as a metal salt)
Spherical silica matting agent (average particle size 10 μm) 1.4 parts nonionic surfactant 3.7 parts The water was adjusted so that the solid content concentration was 9.6%.

(Recording material 28)
In the recording material 2, a recording material 28 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to a backing layer coating solution 21 having the following composition.

<Backcoat layer coating solution 21>
100 parts of Rikabond FK-610 (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 15 ° C, glass transition temperature 46 ° C)
Polyvinyl alcohol (saponification degree 88% polymerization degree 3500) 33 parts boric acid 2 parts calcium chloride dihydrate 2.5 parts (1.9 parts as a metal salt)
Spherical silica matting agent (average particle size 10 μm) 1.4 parts nonionic surfactant 3.7 parts The water was adjusted so that the solid content concentration was 9.6%.

(Recording material 29)
In the recording material 2, a recording material 29 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to a backing layer coating solution 22 having the following composition.

<Backcoat layer coating solution 22>
100 parts of Rikabond FK-610 (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 15 ° C, glass transition temperature 46 ° C)
Polyvinyl alcohol (saponification degree 88% polymerization degree 3500) 33 parts boric acid 2 parts magnesium sulfate heptahydrate 3.9 parts (1.9 parts as a metal salt)
Spherical silica matting agent (average particle size 10 μm) 1.4 parts nonionic surfactant 3.7 parts The water was adjusted so that the solid content concentration was 9.6%.

(Recording material 30)
In the recording material 2, the recording material 30 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to the backing layer coating solution 23 having the following composition.

<Backcoat layer coating solution 23>
100 parts of Rikabond FK-610 (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 15 ° C, glass transition temperature 46 ° C)
Polyvinyl alcohol (degree of saponification 88% degree of polymerization 3500) 33 parts boric acid 2 parts sodium chloride 1.9 parts spherical silica matting agent (average particle size 10 μm) 1.4 parts nonionic surfactant 3.7 parts solids concentration The water was adjusted to 9.6%.

(Recording material 31)
In the recording material 2, a recording material 31 was obtained in the same manner as the recording material 2 except that the backing layer coating solution 1 was changed to a backing layer coating solution 24 having the following composition.

<Backcoat layer coating solution 24>
100 parts of Rikabond FK-610 (Chuo Rika Kogyo Co., Ltd. acrylic resin emulsion, minimum film-forming temperature 15 ° C, glass transition temperature 46 ° C)
Polyvinyl alcohol (degree of saponification 88% degree of polymerization 3500) 33 parts boric acid 2 parts potassium chloride 1.9 parts spherical silica matting agent (average particle size 10 μm) 1.4 parts nonionic surfactant 3.7 parts solid content concentration The water was adjusted to 9.6%.

  The recording materials 27 to 31 obtained above were evaluated in the same manner as in the evaluation method in Table 1, and the results are summarized in Table 4.

  As is apparent from Tables 1 to 4, according to the present invention, the ink absorption is excellent even when printing with a water-based pigment ink jet printer, and the image area does not crack after printing, curling resistance, and scratch resistance on the back surface. In addition, an ink jet recording material excellent in transparency can be obtained.

Claims (2)

An ink receiving layer containing a cationic polyurethane resin, polyvinyl alcohol and boric acid or a salt thereof on one surface of the non-water-absorbing support (however, when the ink receiving layer contains inorganic fine particles, the content of inorganic fine particles Is 5% by mass or less based on the total solid content of the ink receiving layer), and has a minimum film-forming temperature of 10 ° C. or more and 25 ° C. or less as a backing layer on the surface opposite to the ink receiving layer. And a layer containing a resin emulsion having a glass transition temperature of 40 ° C. or higher, polyvinyl alcohol, boric acid or a salt thereof, and a water-soluble polyvalent metal compound, and the solid content coating amount of the backing layer is 2 g / An ink jet recording material characterized by being m ² or more and 100% by mass or less of the solid content coating amount of the ink receiving layer.   Polyvinyl alcohol and water-soluble polyvalent metal compound with respect to 100% by mass of the resin emulsion contained in the backing layer and having a minimum film-forming temperature of 10 ° C. or higher and 25 ° C. or lower and a glass transition temperature of 40 ° C. or higher. Are 20 to 80% by mass and 1 to 8% by mass, respectively, and the content of boric acid or a salt thereof is 0.5 to 25% by mass with respect to the polyvinyl alcohol of the backing layer. Item 10. The ink jet recording material according to Item 1.