JP2002264481A - Ink jet recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording material which shows smooth conveying properties by a printer, outstanding mar resistance and ink absorption, anti-blocking effectiveness and high glossiness and further, can be used for application as a postal card. SOLUTION: This ink jet recording material has an ink receiving layer A which contains inorganic fine particles with an average primary particle diameter of 100 nm or less and a hydrophilic binder formed on one of the sides of a water-resistant support and an ink receiving layer B which contains organic particles and inorganic particles, each having an average primary particle diameter of 100 nm or more and a hydrophilic binder formed on the other side. The ink receiving layer A preferably contains at least one kind of spherical particles with an average primary particle diameter of 1 to 7 μm and at least one kind of spherical particles with an average primary particle diameter of 10 μm or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink-jet recording material having an ink-receiving layer on both surfaces, and more particularly, to one surface having high gloss, photo-like image quality and good touch, and the other surface having scratch resistance. The present invention relates to an ink jet recording material which has high properties, printability and blocking resistance, has good writability, and has excellent transportability in a printer, and can be used for postcard applications.

[0002]

2. Description of the Related Art As a recording material used in an ink jet recording method, a porous material comprising a pigment such as amorphous silica and a water-soluble binder such as polyvinyl alcohol is provided on a support called ordinary paper or ink jet recording paper. There is known a recording material provided with an ink receiving layer.

[0003] For example, Japanese Patent Application Laid-Open No. 55-51583,
Nos. 6-157, 57-107879, 57-10
No. 7880, No. 59-230787, No. 62-160
No. 277, No. 62-184879, No. 62-1833
As disclosed in JP-A-82 and JP-A-64-11877, a recording material obtained by applying a silicon-containing pigment such as silica to a paper support together with an aqueous binder has been proposed.

[0004] Also, Japanese Patent Publication No. 3-56552,
No. 188287, No. 10-81064, No. 10
No.-119423, No. 10-175365, No. 10
-203006, 10-217601, 11
No. -20300, No. 11-20306, No. 11-
No. 34481 and the like disclose a recording material using fine particles of silica synthesized by a gas phase method (hereinafter referred to as gas phase silica). The fumed silica is an ultrafine particle having an average primary particle diameter of several nm to several tens of nm, and is characterized by high gloss and high ink absorption. But,
Because of the ultrafine particles, the surface of the ink receiving layer is apt to be damaged, and there is a problem of double feeding when transported by a printer or the like.

Japanese Patent Application Laid-Open No. 6-55830 proposes a recording paper in which a specific lubricant is contained on the opposite surface of the ink receptive coating layer to improve the transportability of the printer. There is a problem of scratches on the ink receiving surface. Japanese Patent Application Laid-Open No. 7-179025 proposes a recording sheet in which a spherical fine particle polymer is contained in a backing layer of a support. Easy to scratch,
In particular, when fine inorganic fine particles are used for the ink receiving layer, there is a problem that scratches are easily noticeable.

[0006] On the other hand, paper has conventionally been generally used as a support for the ink jet recording material, and the paper itself has a role as an ink absorbing layer. In recent years, while a photo-like recording sheet has been demanded, a recording sheet using a paper support has problems such as gloss, texture, water resistance, cockling (wrinkles or wavy) after printing, and is water-resistant. For example, a resin support paper (polyolefin resin-coated paper) in which a polyolefin resin such as polyethylene is laminated on both sides of a paper support, a plastic film, and the like have been used. However, these water-resistant supports differ from paper supports in that the surface on which the ink-receiving layer is provided has a high smoothness, and the ink-receiving surface is liable to be scratched when rubbed with the back surface. Sending was easy to occur. In particular, there is a problem that the ink-receiving layer is thick because the support itself has no ink absorbency, and the gloss is high, so that the support is easily scratched and conspicuous.

Further, in order to obtain higher ink absorbency, it is necessary to reduce the content ratio of the binder amount to the inorganic fine particles. However, by reducing this ratio, scratches are more likely to occur. .

In particular, both sides have ink jet recording suitability, such as a postcard, and have a photo-like high gloss on the surface,
When printing image quality is required, it is difficult to improve the transportability and scratch resistance on the surface, particularly because there is a restriction due to the decrease in gloss, and sufficient characteristics cannot be obtained. JP-A-8-260
Japanese Patent Publication No. 382 proposes a double-sided recording paper for ink jet recording in which a pigment layer is provided on a paper base material, but sufficient gloss and a printed image cannot be obtained. JP-A-8-11422
Japanese Patent Laid-Open Publication No. H11-214790 proposes that a base paper having an ink receiving layer is bonded with a polyolefin resin laminate layer, but there is a concern that scratches may occur during bonding particularly when a high gloss ink receiving layer is provided, and printer transportability and the like. The scratch resistance was not sufficient. JP-A-2000-301823 discloses an ink-jet recording sheet having a porous ink absorbing layer on one side of a paper base via a relatively thin hydrophobic resin layer and a direct ink absorbing layer on the other side. Although a proposal has been made, there is a description that a matting agent having an average particle diameter of 5 μm or more is contained in a porous ink absorbing layer as a preferred embodiment.
There is no corresponding description about the combination of a specific matting agent and the improvement of transportability and scratch resistance from the ink absorbing layer on the opposite side.
In particular, it is common to print a border line or the like in advance on the ink receiving layer on the postcard addressing surface, but scratches may occur if the ink receiving layer on the opposite surface is high gloss and has a high absorbency for inkjet ink. It's easy to do.

[0009]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a photo-like ink having ink receiving layers on both sides, and having a high glossiness on one side, and excellent ink absorption and blocking resistance. The image quality and good tactile sensation are obtained, and the ink receiving layer on the other side has high scratch resistance, good printability, good writeability,
An object of the present invention is to provide an ink jet recording material having excellent transportability in a printer. In particular, it is an ink jet recording material that does not cause scratches on the opposite side when printed on the address side in advance for postcard use.

[0010]

SUMMARY OF THE INVENTION The object of the present invention is to provide an ink receiving layer (hereinafter referred to as "ink receiving layer" in the table) containing inorganic fine particles having an average primary particle diameter of 100 nm or less and a hydrophilic binder on one surface of a water-resistant support. Layer)), and an ink receiving layer containing an organic pigment and an inorganic pigment having an average particle diameter larger than 100 nm and a hydrophilic binder (hereinafter referred to as a “back ink receiving layer”) is provided on the other surface. This has been achieved by a recording material for inkjet.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
Examples of the water-resistant support used in the present invention include polyester resins such as polyethylene terephthalate, diasate resins, triacetate resins, acrylic resins, polycarbonate resins, polyvinyl chloride, polyimide resins, cellophane, plastic resin films such as celluloid, and paper. And a resin-coated paper obtained by laminating a hydrophobic resin such as a polyolefin resin on at least one surface of paper. The thickness of the water-resistant support is 50
A surface having an ink receiving layer at least having a cutoff value of 0.8 mm specified in JIS-B-0601 from the viewpoint of scratch resistance, transportability and glossiness. Center line average roughness (R
a) is preferably 0.8 to 5 μm.

The polyolefin resin-coated paper support preferably used in the present invention (hereinafter referred to as resin-coated paper) will be described in detail. The resin-coated paper used in the present invention is
Although the water content is not particularly limited, it is preferably in the range of 5.0 to 9.0% from the curl property, more preferably 6.
The range is 0 to 9.0%. The water content of the resin-coated paper can be measured using any moisture measurement method. For example, an infrared moisture meter, an absolute dry weight method, a dielectric constant method, a Karl Fischer method and the like can be used.

The base paper constituting the resin-coated paper is not particularly limited, and generally used paper can be used. More preferably, a smooth base paper used for a photographic support, for example, is preferable. As the pulp constituting the base paper, natural pulp, recycled pulp, synthetic pulp, etc. may be used alone or in combination.
Used as a mixture of more than one species. The base paper is blended with additives generally used in papermaking, such as a sizing agent, a paper strength enhancer, a filler, an antistatic agent, a fluorescent whitening agent, and a dye.

Further, a surface sizing agent, a surface paper strengthening agent, a fluorescent whitening agent, an antistatic agent, a dye, an anchoring agent and the like may be coated on the surface.

The thickness of the base paper is not particularly limited. However, it is preferable that the base paper has good surface smoothness such as by applying a pressure by using a calender or the like during or after papermaking, and the basis weight is 30 to 250 g / m ² is preferred.

As the polyolefin resin for coating the base paper, a homopolymer of an olefin such as low-density polyethylene, high-density polyethylene, polypropylene, polybutene and polypentene or a copolymer comprising two or more olefins such as an ethylene-propylene copolymer may be used. It is a coalescence and a mixture thereof, and various densities and melt viscosity indices (melt index) can be used alone or as a mixture thereof.

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

The main method for producing resin-coated paper is a so-called extrusion coating method in which a polyolefin resin is cast on a running base paper in a state of being heated and melted, and at least one surface thereof is coated with the resin. Further, it is preferable to perform an activation treatment such as a corona discharge treatment or a flame treatment on the base paper before coating the resin on the base paper.
Basically, it is not necessary to coat the resin on the back surface, but it is preferable to coat the resin from the viewpoint of curling prevention. The back surface is usually a matte surface, and the front surface or both front and back surfaces can be subjected to an activation treatment such as a corona discharge treatment or a flame treatment as required. Although the thickness of the resin coating layer is not particularly limited, it is generally coated on one side with a thickness of 5 to 50 μm on the front surface or on both sides. 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 of the resin-coated paper of the present invention on which the ink receiving layer is coated (hereinafter referred to as the surface of the resin-coated paper) is mainly formed by heating and melting a polyolefin resin on one side of the base paper by an extruder, It is manufactured by extruding a film between a substrate 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 surface of the resin layer is shaped into a mirror surface, a fine rough surface, or a patterned silk or mat shape depending on the shape of the cooling roll surface. Can be processed,
From the viewpoint of scratch resistance and transportability, the center line average roughness (R) at a cutoff value of 0.8 mm specified in JIS-B-0601 is used.
a) is preferably 0.8 to 5 μm.

The surface of the resin-coated paper of the present invention on which the ink-receiving layer is provided (hereinafter referred to as the back surface of the resin-coated paper) may be the same as the base paper surface. Mainly heat and melt polyolefin resin with extruder,
Extruded into a film between the base paper and the cooling roll,
It is manufactured by pressing and cooling. At this time, the cooling roll is JIS-B-0 based on the transportability of the printer and the printed image.
It is preferable that the surface of the cooling roll is molded into a finely roughened surface or a patterned, for example, silk-like or mat-like shape so that Ra defined in 601 is 0.8 to 5 μm.

The method of providing the resin coating layer on the front and back surfaces of the base paper is not only to extrude and apply the hot-melt resin, but also to apply an electron beam-curable resin and then irradiate with an electron beam, There is a method of applying a coating liquid, followed by drying and surface smoothing. In any case, resin-coated paper applicable to the present invention can be obtained by performing molding with a heat roll or the like having irregularities.

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

As the inorganic fine particles having an average primary particle diameter of 100 nm or less used in the ink receiving layer shown in the table of the present invention, synthetic silica, alumina, alumina hydrate, calcium carbonate, magnesium carbonate, titanium dioxide and the like are used. Particularly preferably, synthetic silica, alumina, and alumina hydrate are used.

[0024] In the present invention, the amount of the inorganic fine particles used in the ink-receiving layer of the table, preferably 10 to 30 g / m ^2, the range of 13~30g / m ² is more preferable. If the content is more than the above range, cracks are likely to occur, and if the content is too small, the ink absorbency decreases.

The synthetic silica used in the present invention includes those obtained by a wet method and those obtained by a gas phase method. Usually, silica fine particles often refer to wet process silica. As wet silica, silica sol obtained by metathesis of sodium silicate with an acid or the like through an ion exchange resin layer, or colloidal silica obtained by heating and aging this silica sol, gelling silica sol, and changing the production conditions Silica such as those obtained by heating and producing silica gel in which primary particles of several μm to 10 μm are three-dimensional secondary particles having siloxane bonds, and further, silica sol, sodium silicate, sodium aluminate, etc. There are synthetic silicate compounds and the like as main components.

The fumed silica preferably used in the present invention is also called a dry method with respect to a wet method, and is generally produced by a flame hydrolysis method. Specifically, a method of making silicon tetrachloride by burning it with hydrogen and oxygen is generally known, but instead of silicon tetrachloride, silanes such as methyltrichlorosilane and trichlorosilane may be used alone or in a silicon tetrachloride. And can be used in a mixed state.
The fumed silica is commercially available as Aerosil from Nippon Aerosil Co., Ltd. and QS type from Tokuyama Co., Ltd. and can be obtained.

The average particle diameter of the primary particles of the fumed silica of the present invention is preferably from 3 to 50 nm, and in order to obtain higher gloss, it is from 3 to 20 nm and the specific surface area by the BET method is from 90 to 500 m ² / g is preferably used. The BET method referred to in the present invention is one of the methods for measuring the surface area of a powder by a gas phase adsorption method, and is a method for determining the total surface area of 1 g of a sample, that is, the specific surface area, from an adsorption isotherm. Usually, nitrogen gas is often used as the adsorbed gas, and the method of measuring the amount of adsorption from the change in pressure or volume of the gas to be adsorbed is most often used. The most prominent one for expressing the isotherm of multimolecular adsorption is the Brunauer, Emmett, Teller equation, which is called the BET equation and is widely used for determining the surface area.
The surface area is obtained by calculating the amount of adsorption based on the BET formula and multiplying the area occupied by one adsorbed molecule on the surface.

When a fumed silica is used, a recording material having good ink absorption and high gloss can be obtained, but the cohesiveness of secondary particles is weak because of a small amount of silanol groups on the silica surface.
It has the disadvantage of being easily scratched. Due to this drawback, the occurrence of scratches due to the rubbing of the front and back surfaces during the winding process becomes a problem, but this is improved by the present invention.

As the alumina of the present invention, γ-alumina which is a γ-type crystal of aluminum oxide is preferable.
Group crystals are preferred. γ-alumina has one primary particle
Although it can be reduced to about 0 nm, secondary particle crystals of several thousands to tens of thousands of nm are usually reduced to 50 to 3 nm by an ultrasonic wave, a high-pressure homogenizer, a facing collision type jet pulverizer, or the like.
Those pulverized to about 00 nm can be preferably used.

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

The average particle size of the primary particles of the alumina hydrate used in the present invention is preferably 5 to 50 nm, and in order to obtain higher gloss, it is 5 to 20 nm and has an average aspect ratio (average with respect to the average thickness). It is preferable to use tabular particles having a particle size ratio of 2 or more.

The number of ink receiving layers in the table of the present invention is preferably two or more for each purpose. The uppermost layer is for improving glossiness and scratch resistance, and the lower layer is for improving ink absorption. In particular, the uppermost layer furthest from the water-resistant support contains alumina or alumina hydrate having an average primary particle size of 5 to 50 nm, and the other layer contains fumed silica having an average primary particle size of 3 to 50 nm. Thus, an ink jet recording material having excellent gloss and ink absorbability can be obtained. The amount of alumina or alumina hydrate used for the uppermost ink receiving layer is
Preferably 1 to 15 g / m ^2, the range of 1 to 10 g / m ² is more preferable. When the content is more than the above range, the ink absorbency tends to decrease, and when the content is less, the gloss tends to decrease.

The organic particles having an average primary particle size larger than 100 nm used in the ink receiving layer on the back of the present invention include:
Polyethylene, polypropylene, polystyrene, polyacrylate, polymethacrylate, polyacrylamide, polyvinyl chloride, etc. and copolymers thereof,
Urea resins, melamine resins and the like can be mentioned.

The inorganic particles having an average primary particle size larger than 100 nm used in the ink receiving layer on the back of the present invention include:
Examples include silica, alumina, alumina hydrate, aluminum hydroxide, calcium carbonate, magnesium carbonate, titanium dioxide, clay, kaolin, and talc.

In the present invention, the combined use of organic particles and inorganic particles having an average primary particle size of more than 100 nm in the back ink receiving layer improves the transportability in a printer. If the average particle size of the organic particles used is smaller than the average particle size of the inorganic particles, the transportability becomes better. The organic fine particles and the inorganic particles are preferably 10 μm or less, and particularly preferably 5 μm or less, from the viewpoint of touch feeling, print surface quality, and scratch resistance of the ink receiving layer shown in the table. Generally, organic particles have lower affinity for aqueous inks than inorganic particles, and therefore, it is preferable that the particle size of the organic particles is small because density unevenness due to minute white spots in a printed image is improved. By using organic particles and inorganic particles larger than 100 nm in combination in the ink receiving layer on the back side, the writing property is improved, and writing can be performed without any problem even with a hard pencil of about H in particular.

The static friction coefficient between the front and back of the recording material for ink jet is preferably 0.7 or less. The static friction coefficient is AST
23 ° C., 55% R using a friction coefficient measuring device (AB-401, manufactured by Tester Sangyo Co., Ltd.) based on MD-1894-63.
It is measured under the condition of H.

In the present invention, it is preferable to set the organic particles contained in the back ink receiving layer to 0.1 to 50% by weight of the inorganic particles since the ink absorbability becomes better.

The total content of organic particles and inorganic particles in the ink receiving layer on the back of the present invention is preferably from 1 to 10 g / m ² , more preferably from ² to 8 g / m ² , whereby the ink receiving layer is cracked. , Printability and scratch resistance become better.

The average particle diameter of the inorganic fine particles, the organic particles and the inorganic particles of the present invention is determined by observing the dispersed particles with an electron microscope. Was determined as the particle size. The average particle size of the primary particles of the alumina hydrate of the present invention is measured in a flat state in the case of a flat plate. The average thickness of the tabular alumina hydrate is obtained by observing the cut surface of the sheet coated with the alumina hydrate on the film, and the aspect ratio of the alumina hydrate is obtained by the ratio of the average particle diameter to the average thickness. Can be

The ink receiving layer in the table of the present invention has an average particle size of 1 to 7 for improving scratch resistance, transportability and blocking property.
It is preferable to contain at least one kind of spherical particles of μm and at least one kind of spherical particles of 10 μm or more, and it is more preferable that the former is organic particles and the latter is inorganic particles from the feeling of touch. The spherical particles having an average primary particle size of 10 μm or more are preferably larger than the thickness of the ink receiving layer, and the upper limit is about 40 μm. In particular, it is preferable from the viewpoint of scratch resistance and glossiness that the ink receiving layer in the table has two or more layers and the uppermost layer contains the above two types of spherical particles, and the average particle diameter of the particles of 10 μm or more is larger than the thickness of the uppermost layer. It is preferable that the protrusion does not protrude more than 10 μm from the ink receiving layer from the viewpoint of touch. In particular, the uppermost layer contains 1 to 10 g / m ^{2 of} inorganic fine particles, and has an average primary particle size of 1 to 7 μm and 10 to 10 g / m ^2.
0.005 to 0.2 g / m < ² >
When it is contained, a material having good scratch resistance and transportability and excellent in ink absorption and gloss can be obtained. In particular, when printing is performed on the ink receiving layer on the back side, which is the addressing surface, for use in postcards, it is preferable because damage to the ink receiving layer on the front side can be prevented. The printing in this case is printing using a relief printing method, an intaglio printing method, or a lithographic printing method, and scratches due to rubbing between the ink receiving layer and rolls of a printing machine are likely to occur.

The reason why the combined use of spherical particles having an average primary particle size of 1 to 7 μm and 10 μm or more provides better scratch resistance and transportability than the case where each is used alone is presumed as follows. That is, even if the spherical particles of 10 μm or more are used alone, the projections are generated on the surface of the ink receiving layer, so that the scratch resistance and the blocking property are improved. However, the spherical particles of 1 to 7 μm are added to the spherical particles of 10 μm or more when used together. It is expected that scratch resistance and transportability will be greatly improved because it acts as a buffer against external forces.

The spherical particles having an average primary particle size of 1 to 7 μm and 10 μm or more used in the ink receiving layer in the table of the present invention are spherical particles of the same type as the organic particles and inorganic particles used in the back ink receiving layer. Can be used. Spherical particles are recognized as being substantially spherical when observed with an electron microscope, and elliptical particles having a ratio of the major axis to the minor axis of about 0.9 to 1.1 also fall into the spherical category. .

In the ink receiving layer shown in the table of the present invention, a hydrophilic binder is used to maintain the properties as a film and to obtain high transparency and high permeability of the ink. In the use of the hydrophilic binder, it is important that the hydrophilic binder does not swell at the initial penetration of the ink and does not close the voids.From this viewpoint, a hydrophilic binder having a relatively low swelling property at around room temperature is preferable. Used.
Polyvinyl alcohol, polyethylene glycol, starch, dextrin, carboxymethylcellulose and the like and derivatives thereof are used. Particularly preferred hydrophilic binders are completely or partially saponified polyvinyl alcohol or cation-modified polyvinyl alcohol.

Particularly preferred among polyvinyl alcohols are those having a degree of saponification of 80% or more or completely saponified. Polyvinyl alcohol having an average degree of polymerization of 500 to 5000 is preferred.

As the cation-modified polyvinyl alcohol, for example, as described in JP-A-61-10483, a primary to primary amino group or a quaternary ammonium group may be used as the main chain or side chain of polyvinyl alcohol. It is a polyvinyl alcohol contained therein.

As the hydrophilic binder for the ink receiving layer on the back of the present invention, the same hydrophilic binders as those used for the ink receiving layer in the table, gelatin, polyvinylpyrrolidone, pullulan, and derivatives thereof are used. But
Gelatin and polyvinyl alcohol are preferred.

The ink receiving layer in the table of the present invention contains a hydrophilic binder in an amount of 10 to 25% by weight based on the inorganic fine particles, and the ink receiving layer on the back side contains the hydrophilic binder in an amount of 30 to the total of the organic particles and the inorganic particles. When the content is about 120% by weight, ink absorbency, scratch resistance, and transportability are further improved.

In the present invention, preferably, a crack can be prevented by including a water-soluble metal compound in the ink receiving layer. Accordingly, it is possible to further reduce the amount of the hydrophilic binder and further increase the amount of the attached inorganic fine particles in order to improve the ink absorption.

The water-soluble metal compound is selected from, for example, calcium, barium, manganese, copper, cobalt, nickel, aluminum, iron, zinc, zirconium, chromium, magnesium, tungsten and molybdenum as water-soluble polyvalent metal salts. Water-soluble salts of the metals. 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, cupric chloride, copper ammonium chloride (II)
Dihydrate, copper sulfate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel acetate tetrahydrate, nickel ammonium sulfate hexahydrate, nickel amide sulfate Tetrahydrate, aluminum sulfate, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate, aluminum chloride hexahydrate, ferrous bromide, ferrous chloride, ferric chloride, sulfuric acid Ferrous sulfate, ferric sulfate, zinc phenol sulfonate, zinc bromide, zinc chloride, zinc nitrate hexahydrate, zinc sulfate, zirconium acetate, zirconium chloride,
Zirconium chloride octahydrate, zirconium hydroxychloride, chromium acetate, chromium sulfate, magnesium sulfate,
Magnesium chloride hexahydrate, magnesium citrate nonahydrate, sodium phosphotungstate, sodium tungsten citrate, 12 tungstophosphoric acid n hydrate, 12 tungstosilicic acid 26 hydrate, molybdenum chloride, 12 molybdophosphoric acid n-hydrate and the like.

In the present invention, it is preferable to include a cationic polymer in order to improve water resistance. As the cationic polymer, polyethyleneimine,
Polydiallylamine, polyallylamine, JP-A-59-
No. 20696, No. 59-33176, No. 59-331
No. 77, No. 59-155088, No. 60-11389
No. 60-49990, No. 60-83882, No. 60-109894, No. 62-198493, No. 6
3-49478, 63-115780, 63-
280681, JP-A-1-40371, 6-23
No. 4268, No. 7-125411, No. 10-1937
A polymer having a primary to tertiary amino group and a quaternary ammonium group described in JP-A-76-76 is preferably used.
The molecular weight of these cationic polymers is preferably 5,000 or more, more preferably about 5,000 to 100,000.

The amount of the cationic polymer used is 0.5 to 10% by weight, preferably 1 to 10% by weight, based on the amount of the inorganic fine particles in the ink receiving layer shown in the table, and the amount of the organic and inorganic particles in the ink receiving layer on the back side. 7% by weight.

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

In the present invention, the ink receiving layer preferably contains a hardener together with a hydrophilic binder. Specific examples of the hardener include formaldehyde, aldehyde compounds such as glutaraldehyde, diacetyl,
Ketone compounds such as chloropentanedione, bis (2-
(Chloroethyl urea) -2-hydroxy-4,6-dichloro-1,3,5 triazine, U.S. Pat. No. 3,288,7
No. 75, a compound having a reactive halogen, divinyl sulfone, a compound having a reactive olefin as described in U.S. Pat. No. 3,635,718, and an N-type compound as described in U.S. Pat. No. 2,732,316. Methylol compounds, isocyanates described in U.S. Pat. No. 3,103,437, U.S. Pat. Nos. 3,017,280 and 2,
No. 983,611, aziridine compounds, carbodiimide compounds described in US Pat. No. 3,100,704, epoxy compounds described in US Pat. No. 3,091,537, halogen carboxaldehydes such as mucochloric acid And dioxane derivatives such as dihydroxydioxane; inorganic hardeners such as chromium alum, zirconium sulfate, boric acid and borate;
They can be used alone or in combination of two or more. Among these, boric acid or borate is particularly preferred. The addition amount of the hardener is preferably from 0.1 to 40% by weight based on the hydrophilic binder constituting the ink receiving layer,
More preferably, it is 0.5 to 30% by weight.

In the present invention, the ink-receiving layer further contains a surfactant, a hardener, a coloring dye, a coloring pigment, a fixing agent for an ink dye, an ultraviolet absorber, an antioxidant, a dispersant for a pigment, Antifoaming agent, leveling agent, preservative, optical brightener,
Various known additives such as a viscosity stabilizer and a pH adjuster can also be added.

In the present invention, the method of applying the ink receiving layer on the front and back sides is not particularly limited, and a known coating method can be used. For example, there are a slide bead method, a curtain method, an extrusion method, an air knife method, a roll coating method, a ked bar coating method, a bar coater method, a dip method, and the like.

[0056]

EXAMPLES The present invention will be described below in detail with reference to examples, but the contents of the present invention are not limited to the examples.

Example 1 <Preparation of polyolefin resin-coated paper support> A 1: 1 mixture of hardwood bleached kraft pulp (LBKP) and hardwood bleached sulphite pulp (LBSP) was beaten to 300 ml with Canadian Standard Freeness, and pulp was obtained. A slurry was prepared. As a sizing agent, alkyl ketene dimer to pulp is 0.5% by weight, polyacrylamide is 1.0% by weight to pulp, cationized starch is 2.0% by weight to pulp, and polyamide epichlorohydrin resin is a sizing agent. 0.5% by weight of pulp was added and diluted with water to obtain a 1% slurry. The slurry was paper-made to have a basis weight of 170 g / m ² using a fourdrinier paper machine, and was dried and conditioned to obtain a base paper for a polyolefin resin-coated paper. Low density polyethylene 1 having a density of 0.918 g / cm ³
A polyethylene resin composition in which 10% by weight of anatase type titanium is uniformly dispersed with respect to 00% by weight of resin is 32%.
It was melted at 0 ° C., extruded at a rate of 200 m / min to a thickness of 35 μm, and extruded using a finely roughened cooling roll. Ra on the surface of the resin-coated paper was 1.9 μm. 0.962 density on the other side
A blended resin composition of 70 parts by weight of a high density polyethylene resin having a density of 0.918 g / cm ³ and 30 parts by weight of a low density polyethylene resin having a density of 0.918 was similarly melted at 320 ° C. to have a thickness of 30 μm.
m and extrusion-coated using a roughened cooling roll. Ra on the resin-coated surface on the back surface of the resin-coated paper was 1.3 μm.

After the surface of the polyolefin resin-coated paper was subjected to a high-frequency corona discharge treatment, a subbing layer having the following composition was applied and dried so that the gelatin content was 50 mg / m ² , to prepare a support. In addition, a part represents a weight part.

<Undercoat layer> Lime-treated gelatin 100 parts Sulfosuccinic acid-2-ethylhexyl ester salt 2 parts Chromium alum 10 parts

On the back side of the resin-coated paper, a coating solution of the back ink receiving layer having the following composition was applied by a slide coating test coater to a wet silica and polyethylene particle coating amount of 3 g / solid.
It was applied so as to obtain m ² and dried. Subsequently, the coating amount of the fumed silica was 20 g on the surface of the resin-coated paper by applying a coating solution of the ink receiving layer shown in the following table by a slide coating test coater.
/ M ² and dried.

<Coating solution for back ink receiving layer> 100 parts of wet silica (P78A manufactured by Mizusawa Chemical Co., average particle diameter 3 μm) 10 parts of polyethylene particles (average particle diameter 0.15 μm) Gelatin 80 parts (manufactured by Nikka Gelatin, IK -2000) 0.3 part of surfactant

<Coating solution of ink receiving layer in the table> Gas-phase silica 100 parts (Average primary particle diameter 7 nm, specific surface area 300 m ² / g by BET method) Dimethyl diallyl ammonium chloride homopolymer 4 parts (Daiichi Kogyo Seiyaku Co., Ltd. ), Sharoll DC902P, molecular weight 9000) Spherical particles 0.5 part (Asahi Glass Co., Ltd. silica particles H121, average primary particle size 12 μm) Spherical particles 1 part (Sekisui Chemical Co., Ltd. polystyrene, SBX-6, average primary particle size 6 μm) Boric acid 3 parts Polyvinyl alcohol 20 parts (Saponification degree 88%, average polymerization degree 3500) Surfactant 0.3 part

The transportability of the recording material prepared as described above, the scratch resistance of the ink receiving layer on the front and back sides, the ink absorption on the front and back sides, and the glossiness of a blank portion were evaluated by the following methods. Table 1 shows the results.

<Transportability> An inkjet printer MJ-5 manufactured by Seiko Epson Corporation at 23 ° C. and 55% RH.
100 sheets were continuously printed at 100C to evaluate the transportability. ；: Double feed did not occur at all. Δ: Double feed occurred once or twice. X: Double feed occurred three or more times.

<Scratch Resistance of Ink Receiving Layer> Two unprinted ink jet recording materials were stacked, and 100
After pulling out the lower recording material with the g weight placed,
The damage of the ink receiving layer in the table was visually observed. ；: No damage to the ink receiving layer shown in the table was observed. Δ: Slight damage to the ink receiving layer shown in the table was observed, but there was no problem in practical use. X: The ink receiving layer shown in the table was markedly damaged and not practically usable.

<Ink Absorption> An ink jet printer M manufactured by Seiko Epson Co., Ltd. was applied to the ink receiving layer on the front and back sides of the ink jet recording material at 20 ° C. and 65% RH.
Black solid printing was performed with J-5100C, and the ink absorbency was evaluated. ；: The gloss of the printed portion disappeared in less than 5 seconds. Δ: Gloss disappeared in 5 seconds or more and less than 10 seconds. X: It took 10 seconds or more until the gloss disappeared.

<Blocking Resistance> Black solid printing was performed on the surface of the ink receiving layer of the ink jet recording material by the ink jet printer MJ-5100C, and 10 minutes later, the back surface of the same ink jet recording material was overlaid with 5 g /
After being left for 1 hour with a load of ² cm ² , the recording material layered was peeled off and evaluated. ；: The recording material was easily peeled off, and there was no ink transfer. Δ: A little force is required to peel off the recording material, and there is a slight transfer of ink. C: Force is required for peeling off the recording material, and ink transfer is large.

<Glossiness of Blank Area> The glossiness of the blank area of the ink receiving layer of the recording material before printing was observed by oblique light before printing, and evaluated according to the following criteria. ：: High glossiness comparable to a color photograph. Δ: There is glossiness comparable to art and coated paper. ×: There is a sunk glossiness comparable to high quality paper.

Example 2 An ink jet recording material of Example 2 was obtained in the same manner as in Example 1 except that the polyethylene pigment of the back ink receiving layer was 1 part, and evaluation was performed in the same manner as in Example 1. Table 1 shows the results.

Example 3 The ink jet recording material of Example 3 was prepared in the same manner as in Example 1 except that the polyethylene pigment of the ink receiving layer on the back was changed to an average primary particle size of 2.5 μm. Get
Evaluation was performed in the same manner as in Example 1. Table 1 shows the results.

Example 4 An ink jet recording material of Example 4 was obtained in the same manner as in Example 1 except that the polyethylene pigment of the ink receiving layer on the back was changed to one having an average primary particle size of 8 μm. Evaluation was performed in the same manner as in Example 1. Table 1 shows the results.

Example 5 In Example 1, 8 μm wet silica (P7 manufactured by Mizusawa Chemical Co., Ltd.) was used instead of the wet silica having an average particle diameter of 3 μm in the back ink receiving layer.
An ink jet recording material of Example 5 was obtained in the same manner as in Example 1 except that 8D) was used, and evaluated in the same manner as in Example 1. Table 1 shows the results.

Example 6 An ink jet recording material of Example 6 was obtained in the same manner as in Example 1 except that the organic and inorganic spherical particles of the ink receiving layer shown in Table 1 were omitted. Table 1 shows the evaluation results.

Example 7 An ink jet recording material of Example 7 was obtained in the same manner as in Example 1 except that the ink receiving layer shown in Table 1 had the following composition. Table 1 shows the evaluation results.

<Coating Solution for Ink Receiving Layer in Table> 100 parts of fumed silica (average primary particle size: 7 nm, specific surface area by BET method: 300 m ² / g) Dimethyl diallyl ammonium chloride homopolymer: 4 parts (Daiichi Kogyo Seiyaku Co., Ltd. 1) Spherical particles 1 part (Sekisui Chemical Co., Ltd. polystyrene, SBX-6 average primary particle size 6 μm) Spherical particles 0.5 part (Sekisui Chemical Co., Ltd. polystyrene, SBX-17 average primary particle size 17 μm) ) Boric acid 3 parts Polyvinyl alcohol 20 parts (Saponification degree 88%, average polymerization degree 3500) Surfactant 0.3 part

Example 8 In Example 1, the ink receiving layer shown in the table was composed of a lower layer and an upper layer close to the support having the following composition.
Example 8 Example 8 was carried out in the same manner as in Example 1 except that 4 g / m ² and the upper layer of alumina hydrate were applied to a solid content of 6 g / m ^2.
Was obtained. Table 1 shows the evaluation results.

<Coating solution for lower layer of ink receiving layer in table> 100 parts of fumed silica (average primary particle diameter: 12 nm, specific surface area by BET method: 200 m ² / g) Dimethyl diallyl ammonium chloride homopolymer: 4 parts (Daiichi Kogyo Seiyaku Co., Ltd. Sharole DC902P, molecular weight 9000) Boric acid 3 parts Polyvinyl alcohol 15 parts (Saponification degree 88%, average polymerization degree 3500) Surfactant 0.3 part

<Coating Solution for Upper Layer of Ink Receiving Layer in Table> Alumina hydrate 100 parts (pseudo-boehmite, average primary particle diameter 15 nm, flat plate with aspect ratio 5) Dimethyl diallyl ammonium chloride homopolymer 4 parts (Daiichi Kogyo Seiyaku Co., Ltd. Co., Ltd., Sharol DC902P, molecular weight 9000) Spherical particles 0.5 part (Asahi Glass Co., Ltd. silica particles H121, average primary particle diameter 12 μm) Spherical particles 1 part (Sekisui Chemical Co., Ltd. polystyrene, SBX-6, average primary particle diameter 6 μm) ) Boric acid 3 parts Polyvinyl alcohol 15 parts (Saponification degree 88%, average polymerization degree 3500) Surfactant 0.3 part

Example 9 In Example 8, the average primary particle size of the lower layer of the ink receiving layer shown in the table was 12
average primary particle size of 30 nm (B
An ink jet recording material of Example 9 was obtained in the same manner as in Example 8, except that fumed silica having a specific surface area of 50 m ² / g according to the ET method was used, and evaluated in the same manner as in Example 1. Table 1 shows the results.

Example 10 In Example 1, the thickness of the polyolefin resin layer on the surface of the resin-coated paper was set to 15 μm, and the ink receiving layer on the back of Example 1 was coated with wet silica without the polyolefin resin layer on the back. Was applied to a solid content of 20 g / m ² and dried.
Subsequently, the coating liquid for the ink receiving layer shown in the table of Example 1 was similarly applied to the surface of the resin-coated paper by a slide coating apparatus so that the coating amount of fumed silica was 20 g / m ² as a solid content, followed by drying. Thus, a recording material for ink jet was obtained. Table 1 shows the evaluation results. In addition, Ra on the surface of the polyolefin resin layer on which the ink receiving layer shown in the table was provided was 2.0 μm.

Example 11 An ink jet recording material was obtained in the same manner as in Example 1 except that the ink receiving layer shown in Table 1 was first applied and dried, and then the ink receiving layer on the back was applied and dried. Was. Table 1 shows the evaluation results.

Comparative Example 1 The ink jet recording of Comparative Example 1 was carried out in the same manner as in Example 1 except that the two kinds of spherical particles in the ink receiving layer in the front and the polyethylene pigment in the ink receiving layer in the back were omitted. The material was obtained and evaluated in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 2 An ink jet recording material was obtained in the same manner as in Comparative Example 1 except that the ink receiving layer shown in Table 1 was first applied and dried, and then the ink receiving layer on the back was applied and dried. Was. Table 1 shows the evaluation results.

[0084]

[Table 1] ─────────────────────────────────── Conveyance Scratch resistance Ink absorption property Blocking resistance Gloss Front Back Front 表 Example 1 ○ ○ ○ ○ ○ ○ Example 2 ○ 〜 △ ○ 〜 △ ○ ○ ○ 〜 △ ○ Example 3 ○ ○ ○ ○ ○ ○ Example 4 ○ ○ 〜 △ ○ △ ○ 〜 △ ○ Example 5 △ ○ ○ △ ○ 〜 △ ○ Example 6 △ △ ○ ○ △ ○ Example 7 ○ ○ ○ ○ ○ ○ ∼ △ Example 8 ○ ○ ○ ○ ○ ○ Example 9 ○ ○ ○ ○ ○ ○ ∼ △ Example 10 △ ○ ○ ○ ○ ∼ △ ○ ∼ △ Example 11 ○ ○ ○ ○ ○ 〜 △ ○ ─────────────────────────────────── Comparative Example 1 × × ○ ○ × ○ Comparative Example 2 × × ○ ○ × ○ ───────────── ─────────────────────

Results: The ink jet recording materials of Examples 1 to 11 of the present invention have excellent ink absorption, gloss and tactile sensation of the ink receiving layer shown in the table, good transportability with a printer, and are suitable for production and processing. In addition, the result was that the ink receiving layer was not easily scratched during handling. Examples 1 to 11,
The ink receiving layers on the back of the recording materials of Comparative Examples 1 and 2 were all excellent in the sharpness and the pencil writability when printing characters. In addition, a frame line was printed on the back ink receiving layer by an offset printing machine, and the scratches on the front ink receiving layer were evaluated. As a result, good results were obtained except for Example 6, Comparative Examples 1 and 2.

In the recording material of Example 2 in which the polyethylene pigment in the ink receiving layer on the back side was reduced, the transportability, scratch resistance and blocking resistance were slightly lowered as compared with Example 1, but other characteristics were the same as those of Example 1. It was the same as the recording material. In Example 3 in which the average particle size of the polyethylene pigment was 2.5 μm, the same good characteristics as those of the recording material of Example 1 were obtained. In Example 4 in which the average particle size of the polyethylene pigment was 8 μm, the ink absorbency on the back was reduced, and the scratch resistance and the blocking resistance were slightly reduced. The average particle size of the wet silica in the ink receiving layer on the back side is 8
In Example 5 in which the thickness was set to μm, the transportability and the ink absorbency on the back were reduced, and the blocking resistance was slightly lowered. Example 6 in which organic and inorganic spherical particles in the ink receiving layer shown in Table 1 were removed in Example 1.
Although the transportability, the scratch resistance and the blocking resistance were lower than those of Example 1, it was practically usable. In Example 7, in which two types of organic spherical particles were added to the ink receiving layer shown in the table, glossiness and tactile sensation were slightly lower than in Example 1, but the others were good. Example 8 in which the ink receiving layer shown in the table was composed of two layers and spherical particles were used for the upper layer, all the properties were good and the blocking resistance was excellent. In Example 8, where the average primary particle size of the fumed silica in the lower layer of the ink receiving layer shown in the table was 30 nm, the glossiness was slightly lowered. In Example 10, since the curl property was slightly deteriorated, the transportability was lowered, and the glossiness and the anti-blocking property were slightly lowered. However, other characteristics were as good as in Example 1. In Example 11 in which the application order of the front and back ink receiving layers in Example 1 was reversed, slight gloss unevenness due to rubbing was observed on the surface of the front ink receiving layer, and the blocking resistance was slightly reduced. It had the same excellent characteristics as in Example 1.

Comparative Example 1 is a case where the spherical particles shown in Table 1 and the polyethylene pigment of the back ink receiving layer were removed in Example 1, but unevenness of gloss due to friction with a roll was observed on the surface of the back ink receiving layer before evaluation. As a result, transportability, scratch resistance, and blocking resistance were greatly reduced, which was a practical problem. Comparative Example 2
Is the case where the order of application of the front and back ink receiving layers in Comparative Example 1 was reversed. However, uneven gloss due to friction with the roll was observed on the surface of the front ink receiving layer, and transportability, scratch resistance, and The blocking property was greatly reduced, which was a problem in practical use.

[0088]

According to the present invention, there is obtained an ink jet recording material having good printer transportability, scratch resistance, ink absorption, blocking resistance and gloss, and which can be used for postcard applications.

Claims (16)

[Claims] An average primary particle size of 1 on one surface of a water-resistant support.
At least one ink-receiving layer (A) containing inorganic fine particles of not more than 00 nm and a hydrophilic binder is provided, and at least one of inorganic and organic particles having an average primary particle size larger than 100 nm and a hydrophilic binder is provided on the other surface. An ink-jet recording material comprising one ink receiving layer (B). 2. The ink-jet recording material according to claim 1, wherein the water-resistant support is coated with a polyolefin resin on at least a surface of the base paper on which the ink receiving layer A is provided. 3. The ink jet recording material according to claim 1, wherein the inorganic fine particles of the ink receiving layer A are alumina or alumina hydrate having an average primary particle size of 5 to 50 nm. 4. The inorganic fine particles of the ink receiving layer A are fumed silica having an average primary particle size of 3 to 50 nm.
Or the recording material for inkjet according to 2. 5. The ink receiving layer A has an average primary particle size of 1 to 5.
At least one kind of spherical particles of 7 μm and an average primary particle size of 10
The ink-jet recording material according to any one of claims 1 to 4, wherein the material comprises at least one kind of spherical particles having a diameter of not less than μm. 6. The ink-jet recording material according to claim 1, wherein the ink receiving layer A has two or more layers. 7. The uppermost layer of the ink receiving layer A farthest from the water-resistant support contains alumina or alumina hydrate having an average primary particle size of 5 to 50 nm, and the other layers have an average primary particle size of 3 to 50 nm. 7. The ink jet recording material according to claim 6, comprising fumed silica having a thickness of 50 nm. 8. The ink receiving layer A, wherein the uppermost layer farthest from the water-resistant support has at least one kind of spherical particles having an average primary particle size of 1 to 7 μm and at least one kind of spherical particles having an average primary particle size of 10 μm or more. The recording material for inkjet according to claim 6, wherein the recording material comprises: 9. The uppermost layer of the ink receiving layer A contains 1 to 10 g / m ^{2 of} inorganic fine particles, and has an average primary particle size of 1 to 7 μm.
9. The ink-jet recording material according to claim 8, wherein the spherical recording medium and the spherical particles having an average primary particle size of 10 [mu] m or more are contained in a total amount of 0.005 to 0.2 g / m < ² >. 10. The ink receiving layer A has an average primary particle diameter of 1
The spherical particles having a size of from 7 μm to 7 μm are organic particles, and the spherical particles having a size of 10 μm or more are inorganic particles.
10. The ink jet recording material according to any one of 8 and 9. 11. The ink-jet recording material according to claim 1, wherein the average particle size of the inorganic particles and the organic particles of the ink receiving layer B is 10 μm or less. 12. The ink jet recording material according to claim 1, wherein the hydrophilic binder of the ink receiving layer B is gelatin. 13. The ink receiving layer B contains a total of 1 to 10 g / m ^{2 of} organic particles and inorganic particles, and the content of the organic particles is 0.1 to 50% by weight of the inorganic particles. The ink-jet recording material according to claim 1. 14. The ink receiving layer A contains a hydrophilic binder in an amount of 10 to 25% by weight based on the inorganic fine particles, and the ink receiving layer B contains a hydrophilic binder in an amount of 30 to 120% based on the total of the organic particles and the inorganic particles. 14. The ink-jet recording material according to any one of claims 1 to 13, wherein the recording material is contained by weight%. 15. The center line average roughness (Ra) of the surface on which the ink receiving layer A of the water-resistant support is provided at a cutoff value of 0.8 mm specified in JIS-B-0601 is 0.8.
The inkjet recording material according to any one of claims 1 to 14, wherein the thickness is from 5 to 5 m. 16. The ink-jet recording material according to at least one of claims 5, 8, 9 and 10, which is used for postcards. A recording material for ink-jet recording, characterized by being recorded.