JP2006264278A - Ink jet recording sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet recording material which has an ink receiving layer on both surfaces, has high glossiness and photo-like picture quality on one surface, has excellent ink absorbability and writing quality on the other surface, has an aptitude for offset printing, and can be suitably used for a postcard. <P>SOLUTION: The ink jet recording material having the ink receiving layer on both surfaces of a water resistant support is provided with the ink receiving layer (A) composed essentially of inorganic fine particles having an average secondary particle diameter of not larger than 500 nm on one surface (A surface), and with at least two or more ink receiving layers (B) on the other surface, wherein a layer ink receiving layer (B1) nearest to the water resistant support is composed essentially of inorganic fine particles having an average secondary particle diameter of not larger than 500 nm, and the ink receiving layer (B2) remotest from the water resistant support contains synthetic silica having an average secondary particles diameter of 1 to 10 μm and calcium carbonate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording material having an ink receiving layer on both sides, and more particularly to an ink jet recording material suitable for postcard use. More specifically, one side has high gloss and photo-like image quality, and the other side also absorbs ink. The present invention relates to an ink jet recording material having good properties, writability, and offset printing suitability.

  As inkjet recording materials that can be printed on both sides, JP-A-8-174996, JP-A-2000-301823, JP-A-2001-80208, JP-A-2002-29147, and the like have been disclosed.

  Japanese Patent Application Laid-Open No. 8-174996 discloses an ink jet recording material in which an inorganic pigment and a binder are mainly formed on one surface of an ink-absorbing substrate and a cationic substance is applied on the other surface. However, in recent years, photo-like recording sheets have been demanded, and recording sheets using a paper support have problems such as gloss, texture, water resistance, cockling after printing (wrinkles or undulations). Accordingly, water-resistant paper supports, for example, resin-laminated paper (polyolefin resin-coated paper) in which a polyolefin resin such as polyethylene is laminated on both sides of the paper, plastic films, and the like have been used.

  JP-A-2000-301823 (Patent Document 1), JP-A-2001-80208 (Patent Document 2), Japanese Patent Application Laid-Open No. 2001-80208, and Japanese Patent Application Laid-Open No. 2001-80208 have been disclosed. This is disclosed in Japanese Unexamined Patent Publication No. 2002-29147 (Patent Document 3).

  On the other hand, postcards are known as uses of recording materials capable of double-sided printing. For postcards, use of the recording material provided with the ink-receiving layer on both sides of the above-mentioned water-resistant processed support gives a high gloss and texture, but in order to further improve the gloss and ink absorption of the communication surface. In addition, it is preferable to provide a porous ink receiving layer mainly containing an inorganic pigment having an extremely small average particle diameter, such as vapor phase method silica or alumina hydrate.

  In addition, the ink receiving layer on the address side when used as a postcard is required to have sufficient ink absorbability and to be writable with a pencil, a ballpoint pen, a fountain pen, or the like. In order to impart this writing property, so-called roughening is generally performed by adding a relatively large pigment to give the surface of the ink receiving layer unevenness.

  In addition, when used as a postcard, a postal code frame or the like is printed on the address side with an offset printing machine. There are problems in that the ink receiving layer on the address side is damaged by a large number of rubber rollers and brushes in the feeder section of the printing press, resulting in a problem that the blanket becomes dirty and the printing efficiency is deteriorated. It was not a thing. Therefore, the scratch resistance on the address side was an important issue.

  In recent years, with the widespread use of inkjet printers, there has been a rapid increase in demand for inkjet recording materials that are compatible with both printing methods, especially for commercial postcards, due to the low cost of offset printing and the ease of inkjet printing. No particularly effective proposal has been made. This is because the quality for the absorbent pigment required for ink jet printability and the quality for the absorbent pigment required for offset printability cannot be compatible.

  Japanese Patent Application Laid-Open No. 2003-94800 (Patent Document 4) describes that a layer containing colloidal silica is provided on the uppermost layer of an ink receiving layer in order to improve scratch resistance. However, when this technology is applied as a protective layer on the address side, the smoothness is high, so choking occurs after printing on the printing press, and the communication side is also smooth to obtain a high-gloss and photo-like image quality. As a result, the contact area when both surfaces are superposed is increased, resulting in a new problem of blocking.

On the other hand, Japanese Patent Application Laid-Open No. 2004-237650 (Patent Document 5) describes that a coating layer having improved offset printing suitability by containing calcium carbonate in the ink receiving layer is described. It was not possible to provide an inkjet recording paper suitable for postcard use that combines offset printing suitability.
JP 2000-301823 A JP 2001-80208 A JP 2002-29147 A JP 2003-94800 A JP 2004-237650 A

  An object of the present invention relates to an ink jet recording material having an ink receiving layer on both sides, and more particularly to an ink jet recording material suitable for postcard use. More specifically, one side has high gloss and photo-like image quality, and the other side. Another object of the present invention is to provide an ink jet recording material suitable for postcards having good ink absorbability, writing property, and offset printing suitability.

The above object of the present invention has been achieved by the following invention.
(1) An ink-jet recording material having an ink-receiving layer on both sides of a water-resistant support, the ink-receiving layer (A) mainly comprising inorganic fine particles having an average secondary particle diameter of 500 nm or less on one side (A side) And at least two ink receiving layers (B) are provided on the other surface (B surface), and the ink receiving layer (B1) closest to the water-resistant support is provided with inorganic fine particles having an average secondary particle diameter of 500 nm or less. An ink jet recording material, characterized in that the ink receiving layer (B2) which is a main component and is furthest from the water-resistant support contains synthetic silica having an average secondary particle diameter of 1 to 10 μm and calcium carbonate.
(2) The inkjet recording material according to (1), wherein a mixing mass ratio of the synthetic silica and calcium carbonate contained in the ink receiving layer (B2) is 9: 1 to 3: 7.
(3) The inkjet recording material according to (1) or (2), wherein the inorganic fine particles contained in the ink receiving layer (B1) are vapor-phase-process silica.
(4) The inkjet recording material according to (1), (2) or (3), wherein the inkjet recording material is an inkjet recording material for postcards.

  The ink jet recording material of the present invention is suitable for postcards having high glossiness and photo-like image quality on one side, good ink absorbability on the other side, writing properties, and also having offset printing suitability. Inkjet recording material.

Hereinafter, the present invention will be described in detail.
The ink jet recording material of the present invention is particularly suitable for postcard use, and will be described as postcard use hereinafter. In the ink jet recording material of the present invention, the surface (A surface) provided with the ink receiving layer (A) mainly composed of inorganic fine particles having an average secondary particle diameter of 500 nm or less corresponds to the communication surface of the postcard. This is called “communication aspect”. On the other hand, the other surface (B surface) of the water-resistant support is provided with at least two ink receiving layers (B), and the ink receiving layer (B1) closest to the water-resistant support has an average secondary particle. The ink receiving layer (B2) which is mainly composed of inorganic fine particles having a diameter of 500 nm or less and which is farthest from the water-resistant support contains synthetic silica having an average secondary particle diameter of 1 to 10 μm and calcium carbonate, and is a postcard. This will be referred to as “address surface”.

  In addition, the average primary and secondary particle diameter as used in the field of this invention is based on the well-known method observed with an electron microscope (SEM and TEM). The average particle diameter of the primary particles can be obtained as the particle diameter by measuring the diameter of a circle equal to the projected area of each of 100 particles existing within a certain area by observing the dispersed particles with an electron microscope. The average particle diameter of the secondary particles can be determined by observing particles dispersed with a gentle shear force with an electron microscope.

  The ink-jet recording material of the present invention has a photo-like high gloss on the communication side, good ink absorbability when the address side is printed by a printer, and good writing property with a pencil or fountain pen. In addition, when used as a postcard, the postal code frame on the address side is usually printed by a printing machine. In recent years, offset printing has been mainstream, and dirt on the blanket is a cause of deteriorating printing efficiency, which is a big problem. When the ink-absorbing property of an ink jet printer is imparted with a water-resistant support as in the present invention, it is essential to provide an ink receiving layer. In this case, there is a problem that the surface is damaged by a rubber roller or a brush installed in the printing press, and the portion causes blanket contamination.

  The average secondary particle diameter of the synthetic silica used for the ink-receiving layer (B2) of the address surface of the present invention is 1 to 10 μm, particularly 3 to 7 μm, in order to obtain appropriate smoothness as the address surface of the postcard. Is preferred. By setting it as the above range, moderate inkjet printability, writing property, and print surface quality can be obtained as a postal address.

  Synthetic silica includes a wet method and a dry method. Usually, synthetic silica having an average secondary particle size of 1 to 10 μm is produced by a wet method. Wet process silica is classified into precipitation process silica, gel process silica, and sol process silica depending on the production method. In the present invention, precipitation process silica and gel process silica are preferably used. Particularly preferred is gel silica. Gel silica is produced by reacting sodium silicate and sulfuric acid under acidic conditions. In this case, the small silica particles dissolve during ripening and reprecipitate so as to bond the primary particles between the primary particles of the large particles, so that the distinct primary particles disappear and are relatively hard agglomerates with an internal void structure Form particles. For example, it is commercially available as Mizusukacil from Mizusawa Chemical Industry Co., Ltd. and as a silo jet from Grace Japan Co., Ltd. Precipitated silica is produced by reacting sodium silicate and sulfuric acid under alkaline conditions, and the silica particles that have grown are agglomerated and settled, and are then commercialized through the steps of filtration, washing, drying, pulverization and classification. The silica secondary particles produced by this method become loosely agglomerated particles, and particles that are relatively easy to grind are obtained. Precipitated silica is commercially available, for example, as a nip seal from Tosoh Silica Industry Co., Ltd., as a Toku Seal from Tokuyama Co., Ltd., and as a fine seal.

  The synthetic silica used for the ink receiving layer (B2) of the address side of the present invention is dispersed using water as a dispersion medium, and preferably a cationic compound as a dispersant. As the disperser to be used, a commonly used disperser can be used, and examples thereof include a ball mill, a roll mill, a bead mill, a sand mill, a homomixer, a sand grinder, a speed line mill, a microfluidizer, and an ultrasonic homogenizer.

  Examples of the cationic compound used for the dispersion of the synthetic silica include a cationic polymer or a water-soluble metal compound. For example, as the cationic polymer, polyethyleneimine, polydiallylamine, polyallylamine, alkylamine polymer, JP 59-20696, JP 59-33176, JP 59-33177, JP 59 155088, JP 60-11389, JP 60-49990, JP 60-83882, JP 60-109894, JP 62-198493, JP 63-49478. , JP-A-63-115780, JP-A-63-280681, JP-A-1-40371, JP-A-6-234268, JP-A-7-125411, JP-A-10-193976, and the like. In addition, a polymer having a primary to tertiary amino group or a quaternary ammonium base is preferably used. In particular, diallylamine derivatives are preferably used as the cationic polymer. The molecular weight of these cationic polymers is preferably about 2,000 to 100,000, and particularly preferably about 2,000 to 30,000. A molecular weight greater than 100,000 is not preferred because the dispersion becomes too viscous.

  Examples of the water-soluble metal compound include water-soluble polyvalent metal salts, and among them, a compound made of aluminum or a group 4A metal (for example, zirconium or titanium) in the periodic table is preferable. Particularly preferred is a water-soluble aluminum compound. As a water-soluble aluminum compound, for example, as an inorganic salt, aluminum chloride or a hydrate thereof, aluminum sulfate or a hydrate thereof, ammonium alum and the like are known. Furthermore, a basic polyaluminum hydroxide compound which is an inorganic aluminum-containing cationic polymer is known and preferably used.

  The average secondary particle diameter of calcium carbonate used in the ink receiving layer (B2) of the address side of the present invention is preferably 0.15 to 5 μm, particularly preferably 0.3 to 3 μm. By setting it in the above range, the scratch resistance of the address face of the postcard can be effectively improved, and the occurrence of scratches due to rubber rollers and brushes installed in the printing press during offset printing can be suppressed.

  Calcium carbonate is roughly classified into heavy calcium carbonate obtained by physically pulverizing natural limestone and light calcium carbonate obtained by synthesis by a chemical method. Further, the crystal type is classified into a calcite type, an aragonite type, and a vaterite type. Heavy calcium carbonate has the advantages of being inexpensive and capable of high-concentration dispersion, but the shape is indefinite and cannot be controlled, and has the disadvantage of poor ink absorption. . In the present invention, it is required that the original ink absorptivity as an ink jet recording material is not impaired as much as possible. Therefore, light calcium carbonate having good ink absorptivity and easily controlling the shape, particle diameter, etc. as necessary. Is preferably selected.

  The calcium carbonate used in the ink receiving layer (B2) of the address side of the present invention is dispersed using water as a dispersion medium. A dispersant may not be used, but when used, a dispersant similar to that used in the dispersion of the synthetic silica can be preferably used, and a similar disperser can be used. .

  The mixing mass ratio of the synthetic silica and calcium carbonate used in the ink receiving layer (B2) of the address side of the present invention is preferably 9: 1 to 3: 7, more preferably 8: 2 to 4: 6. Particularly preferably, it is 7: 3 to 5: 5. By setting it as the above range, it is possible to achieve both ink-jet printing suitability and post-printing suitability as a postal address and to obtain writing properties.

The total solid content of synthetic silica and calcium carbonate used for the ink receiving layer (B2) of the address side of the present invention is preferably in the range of 0.5 to 10 g / m ² , and preferably 0.5 to 5 g / m. A range of ² is more preferable, and a range of 1 to 4 g / m ² is particularly preferable.

  The address-receiving ink receiving layer (B1) of the present invention is mainly composed of inorganic fine particles having an average secondary particle diameter of 500 nm or less. The term “main body” as used herein means that it contains 50% by mass or more, preferably 60% by mass or more, and more preferably 70% by mass or more of the total solid content of the ink receiving layer.

  In the case where the address surface is composed of a single layer of the ink receiving layer (B2) without providing the ink receiving layer (B1), the adhesive strength between the ink receiving layer (B2) and the water-resistant support is insufficient, and offset printing is performed. In some cases, a part of the coating layer may adhere to the plate cylinder of the printing press and reduce the printing quality, or in some cases, the coating layer may peel off from the support and stain the blanket, greatly reducing workability. is there. In addition, when the address surface is formed of a single layer of the ink receiving layer (B1) without providing the ink receiving layer (B2), the adhesive strength between the ink receiving layer (B1) and the water-resistant support is sufficient. However, as the result of the smoothness of the address surface and the large contact area with the blanket, the coating layer may be peeled off during offset printing, and the blanket may be soiled. The surface texture is not obtained.

  As in the address plane of the present invention, an ink receiving layer (B1) having good adhesion to a water-resistant support is provided in the lowermost layer, and an ink receiving layer (B2) having excellent offset printability and writing properties is provided in the uppermost layer. Thus, the above problem can be solved, and furthermore, high ink absorbability can be obtained even if the total coating amount of the ink receiving layer on the address side is reduced.

  In the present invention, the inorganic fine particles having an average secondary particle diameter of 500 nm or less used for the ink receiving layer (B1) include synthetic silica, alumina, alumina hydrate, wet silica, calcium carbonate, titanium dioxide, and the like. Preferred are vapor phase silica, inorganic fine particles obtained by pulverizing wet method silica, alumina, and alumina hydrate. The average secondary particle diameter of the inorganic fine particles can be obtained from an electron micrograph of an ink receiving layer provided on a support.

  In the present invention, the vapor phase silica preferably used for the ink receiving layer (B1) is also called a dry method as compared with a wet method, and is generally made by a flame hydrolysis method. Specifically, a method of making silicon tetrachloride by burning with hydrogen and oxygen is generally known, but silanes such as methyltrichlorosilane and trichlorosilane can be used alone or silicon tetrachloride instead of silicon tetrachloride. Can be used in a mixed state. Vapor phase method silica is commercially available as Aerosil from Nippon Aerosil Co., Ltd. and QS type from Tokuyama Co., Ltd., and can be obtained.

In the present invention, the average primary particle diameter of the vapor phase silica preferably used for the ink receiving layer (B1) is preferably 5 to 50 nm, and in order to obtain higher gloss, it is 5 to 20 nm and the specific surface area by the BET method. Is preferably 90 to 400 m ² / g. The BET method referred to in the present invention is one of powder surface area measurement methods by vapor phase adsorption, and is a method for determining the total surface area, that is, the specific surface area of a 1 g sample from the adsorption isotherm. Usually, nitrogen gas is often used as the adsorbed gas, and the most frequently used method is to measure the amount of adsorption from the change in pressure or volume of the gas to be adsorbed. The most prominent expression for expressing the isotherm of multimolecular adsorption is the Brunauer, Emmett, and Teller formula, called the BET formula, which is widely used for determining the surface area. The adsorption amount is obtained based on the BET equation, and the surface area is obtained by multiplying the area occupied by one adsorbed molecule on the surface.

  In the present invention, the average primary particle diameter of vapor phase silica preferably used for the ink receiving layer (B1) is preferably 50 nm or less, more preferably 3 to 40 nm, and precipitation silica particles are particularly preferable. The oil absorption amount of the wet process silica in the present invention is preferably in the range of 120 to 210 ml / 100 g, more preferably in the range of 160 to 210 ml / 100 g. The oil absorption is measured based on the description of JIS K-5101.

  Vapor phase silica produced by a normal method has an average secondary particle diameter of 1 μm or more. Therefore, the ink-receiving layer (B1) of the present invention has fine particles until the average secondary particle diameter reaches 500 nm. Grind and use. As a pulverization method, a wet dispersion method in which silica dispersed in an aqueous medium is mechanically pulverized can be preferably used. Wet dispersers used for dispersion and pulverization include media mills such as ball mills, bead mills, sand grinders, pressure dispersers such as high-pressure homogenizers and ultra-high pressure homogenizers, ultrasonic dispersers, and thin film swirl dispersers. In the present invention, it is particularly preferable to use a media mill such as a bead mill.

  In the present invention, the vapor phase silica preferably used for the ink receiving layer (B1) is preferably used in a cationized state. Examples of the cationized vapor-phase silica include those described in JP-A No. 11-321079, JP-A No. 2000-239536, JP-A No. 2001-19421, JP-A No. 2001-80204, JP-A No. 2001-207078, and the like. A method of dispersing vapor phase silica in the presence of a compound is described, and any method can be employed in the present invention. As the cationic compound used for the dispersion or pulverization of the vapor phase silica, the same compounds as those used for the dispersion of the synthetic silica described above can be used.

  In the present invention, the alumina preferably used for the ink receiving layer (B1) includes γ-alumina, which is a γ-type crystal of aluminum oxide, and among them, the δ group crystal is preferable. γ-alumina can make primary particles as small as about 10 nm. Usually, secondary particles of several thousand to several tens of thousands nm are preferably used with an ultrasonic wave, a high-pressure homogenizer, a counter collision type jet pulverizer, or the like. Can be used in which the average secondary particle size is pulverized to about 50 to 300 nm.

In the present invention, the alumina hydrate preferably used for the ink receiving layer (B1) is represented by a constitutional formula of Al ₂ O ₃ .nH ₂ O (n = 1 to 3). The case where n is 1 represents an alumina hydrate having a boehmite structure, and the case where n is greater than 1 and less than 3 represents an alumina hydrate having a pseudo boehmite structure. It can be obtained by a known production method such as hydrolysis of an aluminum alkoxide such as aluminum isopropoxide, neutralization of an aluminum salt with an alkali, or hydrolysis of an aluminate.

  In the present invention, the average primary particle diameter of the alumina hydrate preferably used for the ink receiving layer (B1) is preferably 5 to 50 nm, and in order to obtain higher gloss, it is 5 to 20 nm and the average aspect ratio (average It is preferable to use tabular grains having a ratio of the average particle diameter to the thickness of 2 or more.

In the present invention, the solid content coating amount of the inorganic fine particles used in the ink-receiving layer (B1) is preferably from 5 to 25 g / m ^2, more preferably in the range of 8 to 20 g / m ^2, in particular 10～17G / A range of m ² is preferred.

  In the present invention, a hydrophilic binder is used for the ink receiving layer (B1) and the ink receiving layer (B2) in order to maintain the characteristics as a film and to obtain higher transparency and high ink permeability. It is done. When using a hydrophilic binder, it is important that the hydrophilic binder does not swell during the initial penetration of the ink and block the voids. From this point of view, a hydrophilic binder having a relatively low swellability around room temperature is preferable. Used. Polyvinyl alcohol compounds, polyethylene glycol compounds, starches, dextrin, carboxymethyl cellulose, and derivatives thereof are used, and particularly preferred hydrophilic binders are completely or partially saponified polyvinyl alcohol or cation-modified polyvinyl alcohol.

  Particularly preferred among the polyvinyl alcohols are those having a degree of saponification of 80% or more or those completely saponified. Those having an average degree of polymerization of 200 to 5000 are preferred.

  In the polyvinyl alcohol used in the present invention, two or more kinds of polyvinyl alcohols having different saponification degrees and polymerization degrees can be used in combination.

  In the ink receiving layer (B2), the content of the hydrophilic binder used for the address side of the present invention is preferably 15 to 60% by mass in solid content with respect to the total content of synthetic silica and calcium carbonate. More preferably, it is 20-55 mass%, and the range of 30-50 mass% is especially preferable. In the ink receiving layer (B1), the solid content is preferably in the range of 8 to 30% by mass and more preferably in the range of 10 to 25% by mass with respect to the content of the inorganic fine particles. By setting the content in the above range, the adhesive strength with the water-resistant support, the coating layer strength, the surface strength, surface cracking, and ink absorbency are improved.

  In addition, offset printing suitability can be achieved by setting the surface strength of the address surface of the inkjet recording material of the present invention to 9 or more, preferably 10 or more, as measured by the method using a wax specified in JIS P8129 (1994). It becomes good. The surface strength can be improved by increasing the binder component in the ink receiving layer on the address side. When the surface strength is less than 9, a part of the coating layer adheres to the plate cylinder of the printing press during offset printing, degrading the print quality, or in some cases, the coating layer peels off from the support and stains the blanket. Workability may be greatly reduced.

  Next, the communication side will be described. In the present invention, the ink receiving layer (A) on the communication surface is mainly composed of inorganic fine particles having an average secondary particle diameter of 500 nm or less. The term “main body” as used herein means that it contains 50% by mass or more, preferably 60% by mass or more, and more preferably 70% by mass or more of the total solid content of the ink receiving layer.

  The inorganic fine particles contained in the ink receiving layer (A) provided on the communication surface are not particularly limited, but in order to obtain high gloss, the average secondary particle diameter is 500 nm or less, more preferably 400 nm or less, and particularly 300 nm or less. Is preferred. Examples of such inorganic fine particles having a small average secondary particle diameter include vapor-phase method silica, fine particles obtained by pulverizing wet method silica, inorganic fine particles such as alumina, hydrated alumina, calcium carbonate, magnesium carbonate, and titanium dioxide. Preferably, vapor phase silica, fine particles obtained by pulverizing wet method silica, alumina, and alumina hydrate, which are preferably used in the ink receiving layer (B1) on the address side, are particularly preferable. Gas phase process silica. The inorganic fine particles may be used alone, but may be used by mixing at an arbitrary ratio.

In the invention, the solid content coating amount of the inorganic fine particles in the ink-receiving layer of the communication surface (A) is preferably from 5 to 50 g / m ^2, more preferably in the range of 10 to 40 g / m ^2, in particular 13~35g A range of / m ² is preferred.

  In the present invention, the ink receiving layer (A) on the communication surface is the same as in the case of the address surface in order to maintain the characteristics as a film and to obtain a high transparency and high ink permeability. The same hydrophilic binder as that used for the ink receiving layer (B) of the addressed surface can be used.

  In the present invention, the content of the hydrophilic binder in the ink-receiving layer (A) on the communication surface is preferably in the range of 8 to 30% by mass, particularly preferably in the range of 10 to 25% by mass with respect to the inorganic fine particles.

  In the present invention, the ink receiving layer on the communication surface and the address surface preferably contains a hardening agent together with a hydrophilic binder. Specific examples of the hardener include aldehyde compounds such as formaldehyde and glutaraldehyde, ketone compounds such as diacetyl and chloropentanedione, bis (2-chloroethylurea) -2-hydroxy-4,6-dichloro-1 , 3,5 triazine, a compound having a reactive halogen as described in US Pat. No. 3,288,775, divinyl sulfone, a compound having a reactive olefin as described in US Pat. No. 3,635,718, N-methylol compounds as described in Japanese Patent No. 2,732,316, isocyanates as described in US Pat. No. 3,103,437, US Pat. Nos. 3,017,280 and 2,983,611 described Aziridines such as carbodiimide compounds as described in US Pat. No. 3,100,704, There are epoxy compounds as described in No. 3,091,537, halogen carboxaldehydes such as mucochloric acid, dioxane derivatives such as dihydroxydioxane, chromium alum, zirconium sulfate, boric acid and inorganic hardeners such as borate, These can be used alone or in combination of two or more.

  In the present invention, preferably, the ink-receiving layer on the communication surface and the address surface contains a water-soluble polyvalent metal compound, thereby preventing image bleeding under high humidity.

  Examples of the water-soluble metal compound include water-soluble polyvalent metal salts such as calcium, barium, manganese, copper, cobalt, nickel, aluminum, iron, zinc, zirconium, chromium, magnesium, tungsten, and molybdenum. A water-soluble salt is mentioned. Specifically, for example, calcium acetate, calcium chloride, calcium formate, calcium sulfate, barium acetate, barium sulfate, barium phosphate, manganese chloride, manganese acetate, manganese formate dihydrate, manganese ammonium sulfate hexahydrate, chloride chloride Dicopper, ammonium copper (II) chloride dihydrate, copper sulfate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel acetate tetrahydrate, nickel sulfate Ammonium hexahydrate, nickel amidosulfate tetrahydrate, aluminum sulfate, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate, aluminum chloride hexahydrate, ferrous bromide, ferric chloride Ferrous, ferric chloride, ferrous sulfate, ferric sulfate, zinc phenolsulfonate, bromide Lead, zinc chloride, zinc nitrate hexahydrate, zinc sulfate, zirconium acetate, zirconium chloride, chlorinated zirconium oxide octahydrate, hydroxy zirconium chloride, chromium acetate, chromium sulfate, magnesium sulfate, magnesium chloride hexahydrate, citrate Examples include magnesium nitrate nonahydrate, sodium phosphotungstate, sodium tungsten citrate, 12 tungstophosphoric acid n hydrate, 12 tungstosilicic acid 26 hydrate, molybdenum chloride, 12 molybdophosphoric acid hydrate, and the like.

  In the present invention, preferably, the water resistance can be improved by adding a cationic polymer to the ink receiving layer on the communication side and the address side. Examples of the cationic polymer include polyethyleneimine, polydiallylamine, polyallylamine, JP 59-20696, JP 59-33176, JP 59-33177, JP 59-1555088, JP 60-11389, JP 60-49990, JP 60-83882, JP 60-109894, JP 62-198493, JP 63-49478, JP 63- No. 115780, JP-A 63-280681, JP-A 1-40371, JP-A 6-234268, JP-A 7-125411, JP-A 10-193976, etc. A polymer having a quaternary ammonium base is preferably used. The molecular weight of these cationic polymers is preferably 5,000 or more, and more preferably about 5,000 to 100,000.

  The amount of the cationic polymer used is in the range of 0.5 to 10% by mass, preferably in the range of 1 to 8% by mass in solid content with respect to the inorganic fine particles in both the communication surface and the ink receiving layer on the address side. is there.

  In the present invention, preferably, various ink droplets are contained in the ink receiving layer on the communication surface and the address surface to improve the brittleness of the film. Such oil droplets include hydrophobic high-boiling organic solvents (for example, liquid paraffin, dioctyl phthalate, tricresyl phosphate, silicone oil, etc.) having a solubility in water at room temperature of 0.01% by weight or less, and polymer particles ( For example, particles obtained by polymerizing one or more polymerizable monomers such as styrene, butyl acrylate, divinylbenzene, butyl methacrylate, and hydroxyethyl methacrylate) can be contained. Such oil droplets can be preferably used in the range of 10 to 50% by mass in solid content with respect to the hydrophilic binder.

  In the present invention, the ink receiving layer on the communication side and the address side further includes a coloring dye, a coloring pigment, an ink dye fixing agent, an ultraviolet absorber, an antioxidant, a pigment in addition to the surfactant and the hardening agent. Various known additives such as a dispersant, an antifoaming agent, a leveling agent, an antiseptic, a fluorescent brightening agent, a viscosity stabilizer, and a pH adjusting agent can also be added.

  In the present invention, the communication surface has a configuration in which at least one ink receiving layer is provided, but other ink absorbing layers, ink fixing layers, intermediate layers, and protective layers may be further provided. In addition, the ink receiving layer on the address side has a structure in which at least two ink receiving layers are provided. However, if the ink receiving layer (B2) is the uppermost layer and the ink receiving layer (B1) is the lowermost layer, Further, another ink absorbing layer, an ink fixing layer, and an intermediate layer may be provided.

  Examples of the water-resistant support used in the present invention include polyester resins such as polyethylene terephthalate, disate resin, triacetate resin, acrylic resin, polycarbonate resin, polyvinyl chloride, polyimide resin, cellophane, celluloid and other plastic resin films, and paper. A resin-coated paper in which a resin film is bonded, or a paper coated with a hydrophobic resin such as a polyolefin resin on at least one side of the paper can be used. In the present invention, a resin-coated paper in which a hydrophobic resin such as a polyolefin resin is laminated on both sides of the paper is preferably used. The water-resistant support has a thickness of 50 to 300 μm, preferably 100 to 260 μm.

  The smoothness on the communication surface side of the water-resistant support is preferably high gloss and slightly roughened in consideration of glossiness and printer transportability, and is defined by JIS-B0601. The centerline average roughness Ra (however, the cut-off value is 0.8 mm) is preferably 0.3 μm to 2.6 μm, more preferably 0.5 to 2.0 μm. In addition, the smoothness on the address side of the water-resistant support is preferably slightly roughened in consideration of the transportability of the printer and the printed image, and the center line average roughness defined in JIS-B0601. Ra (however, the cutoff value is 0.8 mm) is preferably 0.3 μm to 5.0 μm, more preferably 0.5 to 3.0 μm.

  The polyolefin resin-coated paper support (hereinafter referred to as resin-coated paper) that is preferably used in the present invention will be described in detail. The water content of the resin-coated paper used in the present invention is preferably in the range of 5.0 to 9.0%, more preferably in the range of 6.0 to 9.0% from the curling property. The moisture content of the resin-coated paper can be measured using an arbitrary moisture measurement method. For example, an infrared moisture meter, an absolute dry weight method, a dielectric constant method, a Karl Fischer method, or the like can be used.

  The base paper constituting the resin-coated paper is not particularly limited, and commonly used paper can be used, but smooth base paper such as used for a photographic support is more preferable. As the pulp constituting the base paper, natural pulp, regenerated pulp, synthetic pulp or the like is used alone or in combination. This base paper is blended with additives such as sizing agent, paper strength enhancer, filler, antistatic agent, fluorescent whitening agent, and dye generally used in papermaking.

  Further, a surface sizing agent, a surface paper strength agent, a fluorescent brightening agent, an antistatic agent, a dye, an anchor agent, and the like may be applied on the surface.

Further, the thickness of the base paper is not particularly limited, but a paper having good surface smoothness, such as compression by applying pressure with a calendar during paper making or after paper making, is preferable, and its basis weight is 30 to 250 g. / M ² is preferred.

  Examples of the polyolefin resin that coats the base paper include olefin homopolymers such as low density polyethylene, high density polyethylene, polypropylene, polybutene, and polypentene, or copolymers composed of two or more olefins such as ethylene-propylene copolymer, and the like. Of various densities and melt viscosity indices (melt index) can be used alone or as a mixture thereof.

  In addition, in the resin of the resin-coated paper, white pigments such as titanium oxide, zinc oxide, talc and calcium carbonate, fatty acid amides such as stearic acid amide and arachidic acid amide, zinc stearate, calcium stearate, aluminum stearate, stearin Fatty acid metal salts such as magnesium acid, antioxidants such as Irganox 1010 and Irganox 1076, blue pigments and dyes such as cobalt blue, ultramarine blue, cecilian blue and phthalocyanine blue, magenta such as cobalt violet, fast violet and manganese purple It is preferable to add various additives such as pigments and dyes, fluorescent brighteners and ultraviolet absorbers in appropriate combinations.

  As a main production method of resin-coated paper, it is produced by a so-called extrusion coating method in which a polyolefin resin is cast on a running base paper in a heated and melted state, and at least one surface thereof is coated with the resin. Further, before the resin is coated on the base paper, the base paper is preferably subjected to an activation treatment such as corona discharge treatment or flame treatment. In the present invention, curling can be prevented preferably by coating the back surface with resin. An active treatment such as a corona discharge treatment or a flame treatment can be applied to the surface or both the front and back surfaces as required. Moreover, there is no restriction | limiting in particular as thickness of a resin coating layer, but generally it coats on the surface or both surfaces by the thickness of 5-50 micrometers on one side. When only one side is coated with a resin, the thickness of the resin coating layer is preferably about 5 to 25 μm from the curl property of the obtained ink jet recording material.

  The surface on which the ink receiving layer (A) of the communication surface of the resin-coated paper of the present invention is coated (hereinafter referred to as the surface of the resin-coated paper) is mainly obtained by heating and melting polyolefin resin on one side of the base paper with an extruder. It is manufactured by extruding into a film between paper and a cooling roll, pressing and cooling. At this time, the cooling roll is used to form the surface shape of the polyolefin resin coating layer, and the resin layer surface is molded into a mirror surface, a fine rough surface, or a patterned silk or mat shape depending on the shape of the cooling roll surface. In consideration of glossiness of the ink receiving layer surface (A surface), the center line average roughness defined by JIS-B0601 on the surface of the resin-coated paper support is preferable. Ra (however, the cut-off value is 0.8 mm) is preferably 0.3 μm to 2.6 μm, more preferably 0.5 to 2.0 μm, and still more preferably 0.8 to 1.6 μm. .

  The surface on which the ink receiving layer (B) of the addressed surface of the resin-coated paper of the present invention is coated (hereinafter referred to as the back surface of the resin-coated paper) is also preferably a communication surface in order to improve curling properties and printed images. The resin coating is applied in the same manner as the surface to be coated. From the transportability and print image in the ink jet printer, the center line average roughness Ra (however, the cut-off value is 0.8 mm) on the back surface of the resin-coated paper support is preferably 0.3 to 5.0 μm, more Preferably it is 0.5-3.0 micrometers, More preferably, it is 0.8-2.0 micrometers.

An undercoat layer may be provided on the front and back surfaces of the resin-coated paper used in the present invention. This undercoat layer is applied and dried in advance on the resin layer surface of the support before the ink receiving layer is applied. The undercoat layer mainly contains a water-soluble polymer or polymer latex that can form a film. Preferred are water-soluble polymers such as gelatin, polyvinyl alcohol, polyvinyl pyrrolidone and water-soluble cellulose, and particularly preferred is gelatin. 10-500 mg / m < ² > is preferable and the adhesion amount of these water-soluble polymers has more preferable 20-300 mg / m < ² >. Further, the undercoat layer preferably contains a surfactant and a hardener. Further, it is preferable to perform corona discharge before applying the undercoat layer to the resin-coated paper.

  In the present invention, the application method of the ink receiving layer on the communication surface and the address surface is not particularly limited. However, when two or more ink receiving layers are applied simultaneously, a slide bead coater, a curtain coater, an extrusion coater, etc. In the case of continuous coating, the coating device can be continuously applied by a combination of the above coating devices, an air knife coater, a rod coater, a blade coater, or the like and the above coating device. In the present invention, simultaneous application means that each layer is applied almost simultaneously, and continuous application means that the upper layer is continuously applied in a short time (usually within about 10 seconds) without a drying step after lower layer application. In order to obtain a uniform ink receiving layer and surface quality, simultaneous application is preferred.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, the content of this invention is not restricted to an Example. Parts and% indicate the solid content or the mass part or mass% of the substantial component.

<Preparation of polyolefin resin-coated paper support>
A 1: 1 mixture of hardwood bleached kraft pulp (LBKP) and hardwood bleached sulfite pulp (LBSP) was beaten to 300 ml with Canadian Standard Freeness to prepare a pulp slurry. As a sizing agent, 0.5% by mass of alkyl ketene dimer with respect to pulp, 1.0% by mass of polyacrylamide with respect to pulp as a strengthening agent, 2.0% by mass of cationized starch with respect to pulp, and polyamide epichlorohydrin resin 0.5% by mass of pulp was added and diluted with water to give a 1% slurry. This slurry was made with a long paper machine to a basis weight of 170 g / m ² , dried and conditioned to obtain a polyolefin resin-coated paper base paper. A polyethylene resin composition in which 10% by mass of anatase-type titanium is uniformly dispersed with respect to 100% by mass of low-density polyethylene having a density of 0.918 g / cm ³ is melted at 320 ° C. on the base paper thus produced, The surface was extrusion-coated so as to have a thickness of 35 μm, and a die-forming surface coating layer was provided using a cooling roll that had been die-molded, and an extrusion coating layer was provided on both sides in the same manner. The Ra value on the front surface was 1.3 μm, and the Ra value on the back surface was 1.2 μm.

After subjecting the surface of the polyolefin resin-coated paper to high-frequency corona discharge treatment, 50 mg of gelatin is applied to an undercoat layer composed of 100 parts of lime-processed gelatin, 2 parts of sulfosuccinic acid-2-ethylhexyl ester salt, and 10 parts of chromium alum. The substrate was prepared by coating and drying so as to be / m ² .

<Dispersion of synthetic silica>
Concentration of 70 parts of synthetic silica (Mizusawa Chemical Co., Ltd., wet process silica, Mizukasil P78A) and 2 parts of quaternary ammonium salt polymer (Samplite KH55, manufactured by Yamato Chemical Co., Ltd.) having an average secondary particle size of 3 μm A synthetic silica dispersion was prepared by dispersing in water to 15% by mass and dispersing with a high-pressure homogenizer.

<Dispersion of calcium carbonate>
Light calcium carbonate having an average secondary particle size of 0.5 μm was dispersed in water to a concentration of 13% by mass and dispersed with a high-pressure homogenizer to prepare a calcium carbonate dispersion.

<Ink receiving layer (B2) coating solution on address side>
In order to 70 parts of synthetic silica, 30 parts of calcium carbonate, 7 parts of boric acid, 45 parts of polyvinyl alcohol (saponification degree 88%, average polymerization degree 3500), and 0.3 part of surfactant are sequentially added to the synthetic silica dispersion. Finally, water was added to a final concentration of 10% by mass to obtain a coating liquid for the ink receiving layer (B2) on the address side.

<Ink-receiving layer (B1) coating solution on address side>
Gas phase method silica (average primary particle diameter 7 nm) 100 parts, dimethyl diallylammonium chloride homopolymer (Daiichi Kogyo Seiyaku Co., Ltd. Charol DC902P) 4 parts is dispersed in water to a concentration of 18% by mass, high pressure A gas phase method silica dispersion was prepared by dispersing with a homogenizer. The average secondary particle diameter of the vapor phase silica after dispersion was 150 nm. To this dispersion, 4 parts of boric acid, 25 parts of polyvinyl alcohol (saponification degree 88%, average polymerization degree 3500), and 0.3 part of surfactant are sequentially added to 100 parts of vapor phase method silica, and finally 12 parts. Water was added so as to have a concentration of mass% to prepare a coating solution for the ink receiving layer (B1) on the address side.

<Ink receiving layer (A) coating solution on communication surface>
In the gas phase method silica dispersion used in the above <address-receiving ink receiving layer (B1) coating solution>, 3 parts of boric acid, polyvinyl alcohol (saponification degree 88%, average polymerization degree) with respect to 100 parts of gas phase method silica 3500) 22 parts and 0.3 part of a surfactant were sequentially added, and finally water was added so as to have a concentration of 12% by mass to obtain an ink receiving layer (A) coating solution on the communication surface.

After the high-frequency corona discharge treatment is applied to the back surface of the resin-coated paper, the solid phase coating amount of the vapor phase method silica is 12 g / m ^{2 using} the ink receiving layer (B1) coating solution as a lower layer, The above ink-receiving layer (B2) coating solution is used as an upper layer, and a multilayer coating is applied with a slide bead coater and dried so that the total solid coating amount of synthetic silica and calcium carbonate is 3 g / m ^2. B) was formed. Subsequently, the ink-receiving layer (A) coating solution for the communication surface is applied to the surface of the resin-coated paper with a slide bead coater so that the solid content coating amount of the vapor phase method silica is 20 g / m ² and dried. An ink receiving layer (A) was formed to obtain an ink jet recording material of Example 1. The mixing mass ratio of the synthetic silica and calcium carbonate contained in the ink receiving layer (B2) is 7: 3.

  The inkjet recording material of Example 2 was obtained in the same manner as in Example 1 except that the mixing mass ratio of the synthetic silica and calcium carbonate contained in the ink receiving layer (B2) of Example 1 was set to 4: 6. .

  Inkjet recording of Example 3 except that the mixing mass ratio of the synthetic silica and calcium carbonate contained in the ink receiving layer (B2) of Example 1 was 2.5: 7.5. Obtained material.

  Inkjet recording of Example 4 except that the mixing mass ratio of the synthetic silica and calcium carbonate contained in the ink receiving layer (B2) of Example 1 was set to 9.5: 0.5. Obtained material.

  The same procedure as in Example 1 was performed except that wet silica having an average secondary particle diameter of 8 μm was used as the synthetic silica contained in the ink receiving layer (B2) of Example 1, and the inkjet recording material of Example 5 was obtained. It was. The mixing mass ratio of the synthetic silica and calcium carbonate contained in the ink receiving layer (B2) is 7: 3.

  The ink jet recording material of Example 6 was prepared in the same manner as in Example 1 except that wet type silica having an average secondary particle size of 1.5 μm was used as the synthetic silica contained in the ink receiving layer (B2) of Example 1. Got. The mixing mass ratio of the synthetic silica and calcium carbonate contained in the ink receiving layer (B2) is 7: 3.

(Comparative Example 1)
The same procedure as in Example 1 was carried out except that gas phase method silica having an average secondary particle diameter of 250 nm was used as the synthetic silica contained in the ink receiving layer (B2) of Example 1, and the inkjet recording material of Comparative Example 1 was used. Obtained. The mixing mass ratio of the synthetic silica and calcium carbonate contained in the ink receiving layer (B2) is 7: 3.

(Comparative Example 2)
The same procedure as in Example 1 was performed except that the synthetic silica contained in the ink receiving layer (B2) of Example 1 had an average secondary particle diameter of 12.5 μm, and an inkjet recording material of Comparative Example 2 was obtained. It was. The mixing mass ratio of the synthetic silica and calcium carbonate contained in the ink receiving layer (B2) is 7: 3.

(Comparative Example 3)
A comparison was made in the same manner as in Example 1 except that the ink receiving layer (B2) was not provided, and the solid content of the vapor phase silica contained in the ink receiving layer (B1) was 15 g / m ^2. The ink jet recording material of Example 3 was obtained.

(Comparative Example 4)
In the same manner as in Example 1, except that the ink receiving layer (B1) was not provided and the total solid content of the synthetic silica and calcium carbonate contained in the ink receiving layer (B2) was 15 g / m ^2. The ink jet recording material of Comparative Example 4 was obtained.

(Comparative Example 5)
An inkjet recording material of Comparative Example 5 was obtained in the same manner as in Example 1 except that the synthetic silica contained in the ink receiving layer (B2) of Example 1 was replaced with calcium carbonate.

(Comparative Example 6)
An ink jet recording material of Comparative Example 6 was obtained in the same manner as in Example 1 except that calcium carbonate contained in the ink receiving layer (B2) of Example 1 was replaced with synthetic silica.

(Comparative Example 7)
Comparative Example 7 was carried out in the same manner as in Example 1 except that wet method silica having an average secondary particle size of 1.5 μm was used instead of vapor phase method silica contained in the ink receiving layer (B1) of Example 1. Inkjet recording material was obtained. The mixing mass ratio of the synthetic silica and calcium carbonate contained in the ink receiving layer (B2) is 7: 3.

(Comparative Example 8)
Example 1 was performed in the same manner as in Example 1 except that wet method silica having an average secondary particle size of 1.5 μm was used instead of vapor phase method silica contained in the ink receiving layer (A) on the communication surface. An ink jet recording material of Comparative Example 8 was obtained.

  The ink jet recording material produced as described above was evaluated as follows. The results are shown in Table 1.

<Gloss of communication surface>
The 60 ° specular gloss of the blank area on the surface of the ink receiving layer on the communication surface was measured. The gloss was measured with a gloss meter (digital gloss meter GM-26D: digital gloss meter manufactured by Murakami Color Research Laboratory) according to JIS Z8741. Table 1 shows the values at that time.

<Ink absorbability (address side)>
Color (C, M, Y) characters are printed on the ink-receiving layer surface of the ink-jet recording material at 20 ° C. and 65% RH with Seiko Epson Corporation ink-jet printer PM-950C to evaluate ink bleeding. did.
○: There is no problem in recognizing characters without being crushed.
Δ: Although there is some crushing of characters, there is no problem to recognize.
×: The characters are crushed and the characters cannot be recognized.

<Writing (address)>
Characters were written on the address side of the inkjet recording material with an HB mechanical pen, and the writing property was evaluated.
○: When writing a character, the character can be recognized without peeling of the coating film.
Δ: When characters are written, the characters can be recognized although there is some peeling of the coating film.
X: When writing characters, the coating film peeled off and character recognition was impossible, or character recognition was impossible in terms of density.

  1000 postal code frames were printed on the address side of the inkjet recording material with a printing machine (Mitsubishi Heavy Industries, Ltd., Diamond 3H-4), and the layers were stacked in the order of printing. The following items were evaluated as offset printing suitability. The ink used was a Carton Self 208 Gold Red S type manufactured by Dainippon Ink & Chemicals, Ltd., and the dampening solution used was a 1% aqueous solution of CDS803 manufactured by Tokyo Ink Co., Ltd. The printing conditions are a room temperature of 21 ° C. and a humidity of 65% RH.

<Scratch resistance of ink jet recording material (address)>
The occurrence of scratches on the address surface due to rubbing of the rollers and brushes provided in the printing press was evaluated according to the following criteria.
○: No scratches are generated.
Δ: Minor scratches are observed, but there is no practical problem.
X: Scratches are so great that it is not practical.

<Coating layer peeling (address surface) of ink receiving layer (B)>
The coating layer peeling during printing was evaluated according to the following criteria.
○: There is no peeling of the coating layer in both the printed and unprinted areas.
Δ: There is some peeling of the coating layer, but there is no practical problem.
X: Exfoliation of the coating layer is great and impractical.

<Blanket stain (address face) during offset printing>
Blanket stains after printing 1000 sheets were evaluated according to the following criteria.
○: The blanket is not dirty and there is no problem.
Δ: Some dirt is seen on the blanket, and there is a possibility that it becomes a problem when the number of sheets increases.
X: It is a level in which a considerable blanket stain is seen with 1000 sheets and becomes a problem.

<Blocking>
Of the 1000 printed sheets, transfer to the 10th communication surface from the bottom was visually evaluated, and blocking was evaluated according to the following criteria.
○: There is no problem because the transfer to the communication side is not seen at all.
Δ: Transfer to the communication surface is slightly observed, but at a level where there is no problem.
X: Transcription to the communication surface is serious and is a problem level.

  From the above results, an ink receiving layer (A) mainly having inorganic fine particles having an average secondary particle diameter of 500 nm or less is provided on both sides of the water-resistant support, and the communication surface is provided with at least 2 on the address side. The ink receiving layer (B) having at least two layers is provided, and the ink receiving layer (B1) closest to the water-resistant support is mainly composed of inorganic fine particles having an average secondary particle diameter of 500 nm or less, and from the water-resistant support. The farthest ink receiving layer (B2) contains synthetic silica having an average secondary particle diameter of 1 to 10 μm and calcium carbonate, so that the communication surface has high gloss and photo-like image quality, and the address surface is ink. An ink jet recording material having good absorbability, writing ability, and offset printing suitability, particularly suitable for postcard use, could be obtained. Further, when the mixing mass ratio of the synthetic silica and calcium carbonate contained in the ink receiving layer (B2) on the address side is 9: 1 to 3: 7, an ink jet recording material having particularly preferable performance can be obtained. It was.

  On the other hand, the inkjet recording material of Comparative Example 1 using synthetic silica having an average secondary particle diameter of 250 nm as the uppermost layer of the address surface has a blanket due to coating layer peeling during printing because the smoothness of the address surface is too high. The aptitude for offset printing such as smudge and blocking after printing deteriorated, and the writing property was also inferior. In addition, in the inkjet recording material of Comparative Example 2 in which the average secondary particle diameter of the synthetic silica on the address surface was changed to 12.5 μm, the effect of calcium carbonate was not observed because the average secondary particle diameter of the synthetic silica was too large. The surface of the address surface was damaged by the rubber rollers and brushes of the feeder section of the printing press, and as a result, the level of blanket contamination was poor and problematic. Next, in the inkjet recording material of Comparative Example 3 in which the address side ink receiving layer (B2) was not provided, the smoothness of the address side surface was too high. The suitability for offset printing such as blocking was deteriorated, and the writing property was also inferior. Next, the inkjet recording material of Comparative Example 4 in which the ink-receiving layer (B1) on the address surface was not provided had a weak adhesive strength with the address surface and the coating layer was peeled off from the water-resistant support. Worsened. Next, the ink jet recording material of Comparative Example 5 which does not contain synthetic silica in the ink receiving layer (B2) on the address side was impractical because the ink absorbability deteriorated. Next, the ink jet recording material of Comparative Example 6 in which the ink receiving layer (B2) on the address side did not contain calcium carbonate was unpractical because the surface was easily damaged and blanket stains were generated. Next, the inkjet recording material of Comparative Example 7 which does not have an ink receiving layer (B1) mainly composed of inorganic fine particles having an average secondary particle diameter of 500 nm or less on the address surface has low adhesive strength with a water-resistant support, The coating layer was peeled off from the water-resistant support and blanket stains were generated. Next, the inkjet recording material of Comparative Example 8 which does not have an ink receiving layer (A) mainly composed of inorganic fine particles having an average secondary particle diameter of 500 nm or less on the communication surface has a 60 ° gloss value of only 5, and is photo-like. It couldn't be called a good image, and it was not at the level that users were satisfied with.

Claims (4)

  An ink jet recording material having an ink receiving layer on both sides of a water-resistant support, wherein an ink receiving layer (A) mainly composed of inorganic fine particles having an average secondary particle diameter of 500 nm or less is provided on one side (A side); At least two or more ink receiving layers (B) are provided on the surface (B surface), and the ink receiving layer (B1) closest to the water-resistant support is mainly composed of inorganic fine particles having an average secondary particle diameter of 500 nm or less. An ink jet recording material, wherein the ink receiving layer (B2) farthest from the water-resistant support contains synthetic silica having an average secondary particle diameter of 1 to 10 μm and calcium carbonate.   The ink jet recording material according to claim 1, wherein the mixing mass ratio of the synthetic silica and calcium carbonate contained in the ink receiving layer (B2) is 9: 1 to 3: 7.   The ink jet recording material according to claim 1 or 2, wherein the inorganic fine particles contained in the ink receiving layer (B1) are vapor phase silica.   The inkjet recording material according to claim 1, wherein the inkjet recording material is an inkjet recording material for postcards.