JP4143562B2 - Inkjet recording material for pigment ink - Google Patents

Description

  TECHNICAL FIELD The present invention relates to an inkjet recording material for pigment ink, and an ink receiving material comprising inorganic fine particles having an average secondary particle diameter of 500 nm or less and a resin binder as a lower layer on a resin-coated paper support in which both surfaces of a base paper are coated with a polyolefin resin layer. An ink jet recording material provided by applying at least two layers of an ink receiving layer (B) as a layer (A) and an upper layer, a pigment ink having excellent ink absorbability and white paper glossiness, and suppressing bronzing of a printing portion The present invention relates to an inkjet recording material.

  In recent years, with the increasing demand for photo-like recording materials, glossiness has become increasingly important. Water resistance of polyolefin resin layer-coated paper (laminated paper with polyolefin resin such as polyethylene) and polyester film An ink jet recording material in which an ink receiving layer mainly composed of inorganic ultrafine particles is coated on a conductive support has been proposed.

  Inkjet printers have been devised for high quality, and efforts to improve photo quality with pigment inks have begun to satisfy both the color development and fastness of images. Pigment inks are known to have higher fastness to light and gas resistance than dye inks, but many of them are inferior in color development to dye inks.

  Therefore, color development is improved by the proposals such as atomizing the dispersed particles of the colorant in the pigment ink and coating the surface of the pigment ink colorant with resin, and the product has been put on the market.

  However, when printing with pigment ink, there is a problem that a change in the hue of the specularly reflected light color is observed (hereinafter referred to as bronzing).

  Japanese Laid-Open Patent Publication No. 2003-48371 is disclosed as an ink recording medium having an ink receiving layer containing a pigment and a water-soluble binder on a support and containing thermoplastic fine particles on the surface layer. JP-A-11-301108 discloses an ink jet recording sheet in which an ink receiving layer made of a water-soluble polymer and a layer made of thermoplastic organic resin particles are sequentially provided on at least one surface of a waterproof support from the side closer to the support. A gazette is disclosed (Patent Documents 1 and 2).

However, the bronzing is not improved in the recording medium of Patent Document 1, and the recording sheet of Patent Document 2 is not satisfactory because the ink absorption and white paper gloss are insufficient.
JP 2003-48371 A JP 11-301108 A

  An object of the present invention is to provide an ink jet recording material for pigment ink that is excellent in ink absorbability and white paper glossiness, and in which bronzing of a printing portion is suppressed.

The above-described problems of the present invention have been achieved by the following (1) and (2) inkjet recording materials for pigment ink.
(1) An ink receiving layer (A) comprising inorganic fine particles having an average secondary particle diameter of 500 nm or less and a resin binder as a lower layer on a resin-coated paper support in which both surfaces of the base paper are coated with a polyolefin resin layer, and an ink as an upper layer In the ink jet recording material provided by applying at least two layers of the receiving layer (B), the ink receiving layer (B) is composed of thermoplastic resin particles having a minimum film forming temperature (MFT) of less than 40 ° C., and the ink receiving layer An ink jet recording material for pigment ink, which is dried at a temperature of 40 ° C. or higher at the time of application of (B) and has a dry solid content of 0.2 g / m ² or less.
(2) The ink-jet recording material for pigment ink according to (1), wherein the ink-receiving layer (B) is applied after the ink-receiving layer (A) is applied.

  According to the present invention, it is possible to obtain an ink jet recording material for pigment ink that is excellent in ink absorbability and white paper glossiness and suppresses the bronzing of the printed portion.

  Hereinafter, the present invention will be described in detail. The ink jet recording material of the present invention comprises an ink receiving layer (A) comprising inorganic fine particles having an average secondary particle diameter of 500 nm or less and a resin binder as a lower layer on a resin-coated paper support in which both surfaces of a base paper are coated with a polyolefin resin layer. ) In the ink jet recording material provided with at least two layers of the ink receiving layer (B) as an upper layer, the ink receiving layer (B) is made of thermoplastic resin particles having a minimum film forming temperature (MFT) of less than 40 ° C. Become. Here, the thermoplastic resin particles are polymer fine particles dispersed in a medium, and are acrylic emulsion, acrylic-styrene emulsion, vinyl acetate-acrylic emulsion, vinyl acetate emulsion, ethylene-vinyl acetate emulsion. , Chlorinated polyolefin emulsion, multi-component copolymer emulsion such as ethylene-vinyl acetate-acrylic, SBR latex, NBR latex, MBR latex, carboxylated SBR latex, carboxylated NBR latex, carboxylated MBR latex, water-soluble urethane resin And water-soluble polyester resins. In addition, a plurality of polymers having different monomer compositions, particle diameters, and polymerization degrees of thermoplastic resin particles can be mixed and used.

  The thermoplastic resin particles used in the present invention have a minimum film formation temperature (MFT) of less than 40 ° C. In order to obtain excellent white paper glossiness, it is preferable to use one having a minimum film formation temperature (MFT) of less than 30 ° C. The minimum film formation temperature (MFT) means the minimum temperature required for film formation by bonding thermoplastic resin particles. This minimum film formation temperature (MFT) can be measured by a temperature gradient plate method as described in Soichi Muroi, “Chemistry of Polymer Latex” (published in 1987).

  The particle diameter of the thermoplastic resin particles used in the present invention is not particularly limited, but those usually in the range of 0.01 μm to 20 μm are used. Within the above range, ink absorbency and white paper gloss are excellent.

  In the present invention, the ink receiving layer (B) is dried at 40 ° C. or higher when applied. In order to obtain more excellent white paper glossiness, it is preferable to dry at 50 ° C. or higher.

The dry solid content of the ink receiving layer (B) of the present invention is 0.2 g / m ² or less. In order to obtain better ink absorbability, the dry solid content is preferably 0.05 to 0.1 g / m ² .

  The support used in the present invention is a polyolefin resin-coated paper in which both surfaces of the base paper are coated with a polyolefin resin layer, and the thickness of the support is preferably 100 μm to 300 μm.

  The base paper constituting the support of the present invention is not particularly limited, and commonly used paper can be used, but smooth base paper used for a photographic support is preferable. As the pulp constituting the base paper, natural pulp, recycled pulp, synthetic pulp or the like is used alone or in combination of two or more. 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 substrate paper preferably has good surface smoothness were such as compressed by applying pressure at the calendar or the like or after papermaking in papermaking, the basis weight 80g / m ² ~250g / m ² is preferred.

  The resin coating layer that covers both sides of the base paper is composed of, for example, two or more olefins such as low density polyethylene, high density polyethylene, polypropylene, polybutene, polypentene, or other olefin homopolymers or ethylene-propylene copolymers. Copolymers and mixtures thereof are used, and those having various densities and melt viscosity indexes (melt index) can be used alone or in combination.

  Further, in the resin of the resin coating layer, 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 method for producing a resin-coated paper support, it is produced by a so-called extrusion coating method in which a polyolefin resin is cast on a traveling base paper in a heated and melted state, and both surfaces of the base paper are coated with the resin. Further, it is preferable to subject the base paper to activation treatment such as corona discharge treatment or flame treatment before coating the resin on the base paper.

  The support of the present invention is produced by heat-melting a resin coating layer on both sides of a base paper with an extruder, extruding it into a film between the base paper and a cooling roll, pressing and cooling.

The support used in the present invention may be provided with an undercoat layer for improving coating properties and interfacial adhesive strength. This undercoat layer is applied and dried on the surface of the resin coating layer 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. Adhesion amount of the water-soluble polymer or polymer ^{latex, 0.1g / m 2 ~2g / m} 2 is preferred. Furthermore, it is preferable that the undercoat layer contains a surfactant or a hardener. Moreover, it is preferable to perform a corona discharge treatment before applying the undercoat layer.

  The ink receiving layer (A) as the lower layer of the present invention contains inorganic fine particles having an average secondary particle diameter of 500 nm or less. The inorganic fine particles of the present invention are preferably synthetic silica, alumina or alumina hydrate.

  Synthetic silica is roughly classified into gas phase method silica or wet method silica depending on the production method. The synthetic silica used in the present invention may be gas phase method silica or wet method silica.

  The gas phase method silica contained in the ink receiving layer (A) of the present invention is produced 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 are also used alone or mixed with silicon tetrachloride instead of silicon tetrachloride. Can be used in the 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.

  The average secondary particle diameter of the vapor phase silica contained in the ink receiving layer (A) of the present invention is 500 nm or less. In order to obtain higher ink absorbability, the average secondary particle diameter is preferably 30 nm to 300 nm, and the average primary particle diameter is preferably 3 nm to 20 nm.

  The average primary particle diameter of the vapor-phase method silica of the present invention is the diameter of a circle equal to the projected area of each of 100 particles existing in a certain area by electron microscope observation of particles dispersed to such an extent that primary particles can be discriminated. It is the average particle size obtained as the primary particle size of the particles. The average secondary particle diameter is obtained by observing the ink-receiving layer of the obtained recording material with an electron microscope, thereby obtaining an average value of the particle diameters of the dispersed aggregated particles to be observed.

  Wet method silica is further classified into precipitation method silica, gel method silica, and sol method silica according to the production method. 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 Co., Ltd., as a Toku Seal from Tokuyama Co., Ltd., and as a fine seal.

  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 Co., Ltd. and as a silo jet from Grace Japan Co., Ltd.

  The precipitated silica or gel silica used in the present invention usually has an average secondary particle diameter of 1 μm or more. In this invention, it grind | pulverizes until an average secondary particle diameter becomes 500 nm or less. Preferably, it grind | pulverizes until an average time particle size becomes 300 nm or less. The average secondary particle diameter of the pulverized precipitated silica or gel silica is the average value of the particle diameters of dispersed aggregated particles observed by observing the ink receiving layer of the obtained recording material with an electron microscope. Is what we asked for.

  The pulverization step of the precipitation method silica or the gel method silica includes a primary dispersion step in which silica fine particles are added to a dispersion medium and mixed (preliminary dispersion), and a secondary in which the silica in the coarse dispersion obtained in the primary dispersion step is crushed. It consists of a dispersion process. The preliminary dispersion in the primary dispersion step can be performed by ordinary propeller stirring, a toothed blade type dispersing machine, turbine type stirring, homomixer type stirring, ultrasonic stirring, or the like. As a method for pulverizing the precipitated silica or the gel silica, a wet dispersion method in which silica dispersed in a dispersion medium is mechanically pulverized can be preferably used. As the wet disperser, a media mill such as a ball mill, a bead mill, and a sand grinder, a pressure disperser such as a high pressure homogenizer, and an ultra high pressure homogenizer, an ultrasonic disperser, and a thin film winding disperser can be used. In the present invention, a media mill such as a bead mill is particularly preferably used.

  The sol method silica is also called colloidal silica, and is obtained by heating and aging a silica sol obtained through metathesis of sodium silicate acid or the like through an ion exchange resin layer.

  The average secondary particle diameter of the colloidal silica used for the ink receiving layer (A) of the present invention is 500 nm or less. When the colloidal silica primary particles are in a monodispersed state, the average primary particle diameter may be 500 nm or less. It is also possible to use those in which primary particles have an agglomerated structure and exist stably as secondary particles, in which case the average secondary particle size is 300 nm or less, and the average primary particle size is 20 nm or less. preferable. The average secondary particle diameter of the colloidal silica is obtained by observing the ink receiving layer of the obtained recording material with an electron microscope, thereby obtaining an average value of the particle diameters of the dispersed aggregated particles to be observed.

  The colloidal silica used in the ink-receiving layer (A) of the present invention is obtained by dispersing silicon dioxide obtained by heating and aging silica sol obtained through metathesis or ion exchange resin layer with sodium silicate acid in colloidal form in water. It is a wet method synthetic silica having an average primary particle size of about several nm to 100 nm. Colloidal silica is available from Nissan Chemical Industries, Ltd. Snowtex ST-20, ST-30, ST-40, ST-C, ST-N, ST-20L, ST-O, ST-OL, ST-S. ST-XS, ST-XL, ST-YL, ST-ZL, ST-OZL, ST-UP, ST-OUP, ST-PS-MO and the like are commercially available.

  The colloidal silica used in the ink receiving layer (A) of the present invention can be used in combination with two or more kinds of colloidal silica having different average primary particle diameters in order to improve ink absorbency while maintaining gloss. Further, examples of the colloidal silica having such an aggregated structure include ST-UP, ST-OUP, ST-PS-MO and the like among the above-mentioned commercial products.

  The surface of the colloidal silica may be modified to be cationic. In order to modify the surface cationically, polyethyleneimine, polydiallylamine, polyallylamine, alkylamine polymer, and primary to tertiary amino groups and quaternary ammonium bases are used. Cationic polymers having can be used.

  Colloidal silica whose surface is modified with an aluminum compound may be used. In that case, an aluminum compound may be added to colloidal silica for modification, or commercially available alumina-modified colloidal silica may be used as it is. As the alumina-modified colloidal silica, ST-AK, ST-AK-L, ST-AK-UP, ST-PS-M-AK and the like are commercially available from Nissan Chemical Industries, Ltd.

  The average secondary particle diameter of alumina contained in the ink receiving layer (A) of the present invention is 500 nm or less. In order to obtain higher ink absorbability, it is preferable that the average secondary particle diameter is 50 nm to 300 nm and the average primary particle diameter is 10 nm to 100 nm. As alumina, γ-alumina, which is a γ-type crystal of aluminum oxide, is preferable, and γ group crystal is particularly preferable. The average secondary particle diameter of alumina is obtained by observing the ink receiving layer of the obtained recording material with an electron microscope, thereby obtaining the average value of the particle diameters of the dispersed aggregated particles to be observed.

The alumina hydrate contained in the ink receiving layer (A) of the present invention can be expressed 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.

  The average secondary particle diameter of the alumina hydrate used in the present invention is 500 nm or less. In order to obtain higher ink absorbability, it is preferable to use tabular grains having an average primary particle diameter of 5 nm to 50 nm and an average aspect ratio (ratio of average particle diameter to average thickness) of 2 or more. . The average secondary particle diameter of the alumina hydrate is obtained by observing the ink-receiving layer of the obtained recording material with an electron microscope, and obtaining the average value of the particle diameters of the dispersed aggregated particles to be observed. .

  In the ink receiving layer (A) of the present invention, it is preferable to select and use a hydrophilic binder from the viewpoint of high transparency and high ink permeability. In using the hydrophilic binder, it is important that the hydrophilic binder does not swell during the initial penetration of the ink and closes the voids. From this viewpoint, a hydrophilic binder having a relatively low swellability at around room temperature is preferable. Used. Preferred hydrophilic binders are fully or partially saponified polyvinyl alcohol or cation-modified polyvinyl alcohol.

  Among the polyvinyl alcohols, those partially saponified or completely saponified with a saponification degree of 80% or more are preferable. Polyvinyl alcohol having an average degree of polymerization of 500 to 5000 is preferred.

  The cation-modified polyvinyl alcohol is, for example, a polyvinyl alcohol having a primary to tertiary amino group or a quaternary ammonium group in the main chain or side chain of polyvinyl alcohol as described in JP-A-61-110483. It is.

  In the ink receiving layer (A) of the present invention, a preferable range of the mixing ratio of the hydrophilic binder and the inorganic fine particles is appropriately selected depending on the kind of the inorganic fine particles. The synthetic silica is preferably used in an amount of 10 to 30% by mass, particularly preferably 12 to 25% by mass. It is preferable to use 5 to 25% by mass, particularly 7 to 15% by mass, with respect to alumina or alumina hydrate. In addition, it is preferable to use 1-15 mass% with respect to colloidal silica, and it is preferable to use 5-10 mass% especially.

  The ink receiving layer of the present invention can contain various oil droplets in order 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 mass 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 relative to the hydrophilic binder.

The ink receiving layer (A) of the present invention may be a single layer or two or more layers. The dry solid content coating amount of the ink receiving layer (A) varies depending on the inorganic fine particles to be coated. Dry solid coating amount in the case of fumed silica single layer is preferably ^{5g / m 2 ~30g / m 2} , the range of 10g / m ² ~25g / m ² is more preferable. Dry solid coating amount in the case of alumina and alumina hydrate single layer is preferably ^{10g / m 2 ~40g / m 2} , more preferably ^{15g / m 2 ~35g / m 2} . 10 g / m ^{2 to} 40 g / m ² is preferable, and 15 g / m ^{2 to} 35 g / m ² is more preferable as the total dry solid content when the vapor phase method silica is layered with alumina and alumina hydrate. When a colloidal silica layer is provided, it is preferably applied to a vapor phase silica monolayer, an alumina and alumina hydrate monolayer, and a vapor phase silica and an alumina and alumina hydrate multilayer. layer dry solid coating amount is preferably from ^{0.1g / m 2 ~3g / m 2} , the range of 0.3g / m ² ~2g / m ² is more preferable. When the colloidal silica layer is provided, the dry solid content coating amount of the vapor phase method silica layer, the alumina and alumina hydrate layer, and the multilayer of vapor phase method silica and alumina and alumina hydrate is the same as when the colloidal silica is not provided. It is preferable that

  In the present invention, the application method for forming the ink receiving layer is not particularly limited, but it is preferable to apply the ink receiving layer (B) after applying the ink receiving layer (A) (hereinafter referred to as sequential application). Sequential application is to apply the ink receiving layer (B) coating liquid after the total solid content of the ink receiving layer (A) reaches 50% by mass or more. In order to obtain more excellent white paper glossiness, the total solid content concentration is preferably 80% by mass or more. Examples of the application method include simultaneous application, continuous application, and sequential application. In the case of simultaneous application, application devices such as a slide bead coater, curtain coater, and extrusion coater can be used. In the case of continuous coating and sequential coating, a combination with the above coating apparatus, an air knife coater, a rod coater, a blade coater, a gravure coater, or the like can be applied in combination with the above coating apparatus. In the present invention, simultaneous application means that the respective layers are 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.

  The ink receiving layer (A) of the present invention preferably contains a hardener 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. Among these, boric acid or borate is particularly preferable. The addition amount of the hardener is preferably 0.1 to 40% by mass, more preferably 0.5 to 30% by mass with respect to the hydrophilic binder constituting the ink receiving layer.

  In the present invention, in addition to the surfactant and the hardening agent, all the ink receiving layers further include a coloring dye, a coloring pigment, a fixing agent for the ink dye, an ultraviolet absorber, an antioxidant, a pigment dispersant, a quencher. Various known additives such as foaming agents, leveling agents, preservatives, optical brighteners, viscosity stabilizers, and pH adjusters can also be added.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, the content of this invention is not restricted to an Example.

<Production of 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. The sizing agent and alkyl ketene dimer were 0.5% by mass of pulp, 1% by mass of polyacrylamide as a strength agent, 2% by mass of cationized starch, 2% by mass of pulp, and polyamide epichlorohydrin resin by 0.1% of pulp. 5% by mass 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 base paper for the support. 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. Then, the resin coating layer on the ink receiving layer coating surface side was provided while being extruded with a cooling roll having a finely roughened surface and extruded at 200 m / min to a thickness of 30 μm. On the opposite side to melt at similarly 320 ° C. The blend resin composition of the low density polyethylene resin 30 parts by weight of a density 0.962 g / cm high-density polyethylene resin 70 parts by weight of ³ and a density 0.918 g / cm ^3, A resin coating layer was provided while cooling with a cooling roll to a thickness of 25 μm.

After the high-frequency corona discharge treatment was performed on the surface of the support where the ink-receiving layer was applied, the undercoat layer having the following composition was applied and dried so that the gelatin content was 50 mg / m ² . Hereinafter, “parts” represents solid parts or mass parts of substantial components.

<Underlayer>
Lime-processed gelatin 100 parts Sulfosuccinic acid-2-ethylhexyl ester salt 2 parts Chrome alum 10 parts

The ink receiving layer (A-1) having the following composition was coated on the support with a slide bead coating device so that the dry solid content was 25 g / m ² , cooled at 5 ° C. for 30 seconds, and then the ink receiving layer (A-1). ) Is dried at 45 ° C. and 10% RH, and the gravure coating apparatus is used so that the dry solid content of the ink receiving layer (B-1) having the following composition is 0.1 g / m ^2. Were sequentially applied and dried at 50 ° C. In addition, the average secondary particle diameter of the silica fine particle by electron microscope observation was 80 nm.

<Ink receiving layer (A-1)>
Gas phase method silica 100 parts dimethyldiallylammonium chloride homopolymer 3 parts (Sharol DC902P manufactured by Daiichi Kogyo Seiyaku Co., Ltd., molecular weight 9000)
Boric acid 5 parts polyvinyl alcohol 23 parts (saponification degree 88%, average polymerization degree 3500)

<Ink receiving layer (B-1)>
Boncoat 5450 100 parts (styrene-acrylic emulsion manufactured by Dainippon Ink & Chemicals, Inc., MFT: 20 ° C., particle size: 0.1 μm)

  The same procedure as in Example 1 was conducted except that the ink receiving layer (A-1) of Example 1 was changed to an ink receiving layer (A-2) having the following composition using a wet silica dispersion obtained by the following method. Thus, the recording material of Example 2 was produced. In addition, the average secondary particle diameter of the silica fine particles by electron microscope observation was 100 nm.

<Wet process silica dispersion>
Dimethyldiallylammonium chloride homopolymer (molecular weight 9,000, 4 parts) and precipitated silica (nip seal VN3, average secondary particle size 23 μm, 100 parts) are added to water, and a sawtooth blade type disperser (blade peripheral speed) 30 m / sec) was used to make a preliminary dispersion. Next, the obtained preliminary dispersion was passed once through a bead mill under the conditions of a zirconia bead having a diameter of 0.3 mm, a filling rate of 80 vol%, and a disk peripheral speed of 10 m / sec. A wet silica dispersion having a secondary particle size of 100 nm was obtained.

<Ink receiving layer (A-2)>
Wet process silica dispersion (as silica solid content) 100 parts boric acid 1 part polyvinyl alcohol 15.5 parts (saponification degree 88%, average polymerization degree 3500)

The same procedure as in Example 1 except that the ink receiving layer (A-1) of Example 1 was changed to an ink receiving layer (A-3) having the following composition so that the dry solid content was 35 g / m ^2. Thus, the recording material of Example 3 was produced. The average secondary particle diameter of the alumina hydrate particles as observed by an electron microscope was 80 nm.

<Ink receiving layer (A-3)>
100 parts of alumina hydrate (Dispersal. HP-14 manufactured by SASOL)
Nitric acid 1.4 parts Boric acid 0.2 parts Polyvinyl alcohol 9.5 parts (degree of saponification 88%, average degree of polymerization 3500)

The ink receiving layer (A-1) of Example 1 was printed in order from the side closer to the support, the ink receiving layer (A-1), the ink receiving layer (A-3), and the ink receiving layer (A-4) having the following composition. change in), the dry solid content of the ink receiving layer (a-1) is 10 g / m ^2, the ink-receiving layer (a-3) is 20 g / m ^2, the ink-receiving layer (a-4) is 1 g / m ² A recording material of Example 4 was produced in the same manner as in Example 1 except that The average secondary particle size of vapor phase silica and alumina hydrate as observed by electron microscope was 80 nm.

<Ink receiving layer (A-4)>
ST-AK-L 100 parts (Alumina modified colloidal silica monodisperse particles, average primary particle size: 50 nm, manufactured by Nissan Chemical Industries)
4 parts of polyvinyl alcohol (saponification degree 88%, average polymerization degree 3500)
Surfactant 1 part

  A recording material of Example 5 was produced in the same manner as in Example 1 except that the ink receiving layer (B-1) of Example 1 was changed to the following composition ink receiving layer (B-2). In addition, the average secondary particle diameter of the silica by electron microscope observation was 80 nm.

<Ink receiving layer (B-2)>
Boncoat EC-840 100 parts (acrylic emulsion manufactured by Dainippon Ink and Chemicals, MFT: 20 ° C., particle size: 0.4 μm)

  A recording material of Example 6 was produced in the same manner as in Example 1 except that the ink receiving layer (B-1) of Example 1 was changed to the following composition ink receiving layer (B-3). In addition, the average secondary particle diameter of the silica by electron microscope observation was 80 nm.

<Ink receiving layer (B-3)>
Boncoat EC-9160 100 parts (vinyl acetate-acrylic emulsion manufactured by Dainippon Ink and Chemicals, MFT: 9 ° C., particle size: 0.3 μm)

  A recording material of Example 7 was produced in the same manner as in Example 1 except that the ink receiving layer (B-1) of Example 1 was changed to the following composition ink receiving layer (B-4). In addition, the average secondary particle diameter of the silica by electron microscope observation was 80 nm.

<Ink receiving layer (B-4)>
Boncoat EC-2310 100 parts (vinyl acetate emulsion manufactured by Dainippon Ink and Chemicals, MFT: 16 ° C., particle size: 0.3 μm)

  A recording material of Example 8 was produced in the same manner as in Example 1 except that the ink receiving layer (B-1) of Example 1 was changed to the following composition ink receiving layer (B-5). In addition, the average secondary particle diameter of the silica by electron microscope observation was 80 nm.

<Ink receiving layer (B-5)>
Evadic EV-15 100 parts (Ethylene-vinyl acetate emulsion manufactured by Dainippon Ink & Chemicals, MFT: 0 ° C., particle size: 0.2 μm)

  A recording material of Example 9 was produced in the same manner as in Example 1 except that the ink receiving layer (B-1) of Example 1 was changed to the following composition ink receiving layer (B-6). In addition, the average secondary particle diameter of the silica by electron microscope observation was 80 nm.

<Ink receiving layer (B-6)>
100 parts of Luck Star 5215A (carboxylated styrene-butadiene latex manufactured by Dainippon Ink & Chemicals, Inc., MFT: 0 ° C. or less, particle size: 0.2 μm)

  A recording material of Example 10 was produced in the same manner as in Example 1 except that the ink receiving layer (B-1) of Example 1 was changed to the following composition ink receiving layer (B-7). In addition, the average secondary particle diameter of the silica by electron microscope observation was 80 nm.

<Ink receiving layer (B-7)>
Boncoat CG-5030 100 parts (acrylic-urethane resin particles manufactured by Dainippon Ink & Chemicals, Inc., MFT: 10-12 ° C., particle size: 0.2 μm)

  Except for changing the ink receiving layer (B-1) from the sequential application method by the gravure coating device to the simultaneous application method with the ink receiving layer (A-1) by the slide bead coating device, the same as in Example 1. Thus, a recording material of Example 11 was produced. In addition, the average secondary particle diameter of the silica by electron microscope observation was 80 nm.

(Comparative Example 1)
A recording material of Comparative Example 1 was produced in the same manner as in Example 1 except that the ink receiving layer (B-1) was changed to the ink receiving layer (B-8) having the following composition. In addition, the average secondary particle diameter of the silica by electron microscope observation was 80 nm.

<Ink receiving layer (B-8)>
Boncoat 5391 100 parts (Acrylic-styrene emulsion manufactured by Dainippon Ink & Chemicals, Inc., MFT: 60 ° C. or more, particle size: 0.1 μm)

(Comparative Example 2)
A recording material of Comparative Example 2 was produced in the same manner as in Example 1 except that the ink receiving layer (B-1) was sequentially applied with a gravure coating apparatus and dried at 30 ° C. In addition, the average secondary particle diameter of the silica by electron microscope observation was 80 nm.

(Comparative Example 3)
A recording material of Comparative Example 3 was produced in the same manner as in Example 1 except that the dry solid content of the ink receiving layer (B-1) was 0.5 g / m ² . In addition, the average secondary particle diameter of the silica by electron microscope observation was 80 nm.

(Comparative Example 4)
A recording material of Comparative Example 4 was produced in the same manner as in Example 1 except that the ink receiving layer (B-1) was not applied. In addition, the average secondary particle diameter of the silica by electron microscope observation was 80 nm.

  The following evaluation was performed using the inkjet recording material produced as described above. The results are shown in Table 1.

<Blank glossiness>
The glossiness of the blank paper was visually evaluated.
A: Very close to photographic paper.
○: Slightly inferior to photographic paper, but practically no problem
×: Close to matte paper and bad.

<Ink absorbability>
Immediately after printing, C, M, Y, K, R, G, and B were solidly printed at the maximum ink discharge amount with an ink jet printer (PX-G900 manufactured by Seiko Epson Corporation) equipped with pigment ink. The PPC paper was placed on the printing portion and lightly pressed, and the degree of ink transferred to the PPC paper was visually observed and evaluated according to the following criteria.
A: No transfer at all.
○: Slightly transferred.
X: Transfer is large and actual use is impossible.

<Bronzing>
Using an ink jet printer (PX-G900 manufactured by Seiko Epson Corporation) equipped with a pigment ink, C was solid-inked at the maximum ink discharge amount, visually observed, and evaluated according to the following criteria.
A: Some can be confirmed.
○: Although it can be confirmed, there is no practical problem.
×: Can be clearly confirmed, impractical.

From the above results, it can be seen that the ink jet recording material of the present invention has excellent ink absorptivity and white paper glossiness and suppresses bronzing of the printing portion. In Comparative Example 1 in which the minimum film forming temperature (MFT) of the ink receiving layer (B) was not less than 40 ° C., the glossiness of blank paper was not satisfactory. In Comparative Example 2 in which the drying temperature at the time of applying the ink receiving layer (B) was not 40 ° C. or higher, the glossiness of blank paper was not satisfactory. In Comparative Example 3 where the dry solid content of the ink receiving layer (B) was not 0.2 g / m ² or less, the ink absorptivity was not satisfactory. In Comparative Example 4 in which the ink receiving layer (B) was not applied, bronzing was not satisfactory.

Claims (1)

An ink receiving layer (A) composed of inorganic fine particles having an average secondary particle diameter of 500 nm or less and a resin binder as a lower layer and an ink receiving layer (upper layer) on a resin-coated paper support in which both surfaces of the base paper are coated with a polyolefin resin layer. B) In the ink jet recording material provided by applying at least two layers, the ink receiving layer (B) is made of thermoplastic resin particles having a minimum film forming temperature (MFT) of less than 40 ° C., and the ink receiving layer (B) An ink jet recording material for a pigment ink, which is dried at 40 ° C. or higher when applied and has a dry solid content of 0.2 g / m ² or less.