JP3485670B2 - Ink jet recording sheet - Google Patents

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 sheet mainly using a water-based ink, and more particularly to an ink jet recording sheet excellent in image reproducibility, drying property and water resistance and having high gloss. is there.

[0002]

2. Description of the Related Art Ink-jet recording has no noise and is capable of high-speed printing, and has been adopted rapidly in terminal printers and the like and has been rapidly spread in recent years. In addition, it is easy to perform multicolor recording by using a plurality of ink nozzles, and multicolor inkjet recording by a multicolor inkjet recording system among various inkjet recording systems has been studied. In recent years, in particular, as a hard copy creating apparatus for image information such as characters and various figures created by a computer, the use of an inkjet printer capable of forming a complicated image quickly and accurately has been attracting attention. Further, as an application field of an ink jet printer, which has received a great deal of attention in recent years, it is an application of a color plate in a printing field in which image quality close to that of a photograph is required and a design image output in a design section.

As ink for ink jet recording,
From the viewpoint of safety and recording characteristics, an ink mainly containing water and a polyhydric alcohol is used to prevent clogging of the ink and improve ejection characteristics.

As a recording sheet used in the ink jet recording system, a recording sheet comprising a support and a porous ink absorbing layer provided on a support, which is conventionally called ordinary paper or ink jet recording paper, has been used. .

However, there are some serious problems when these conventional recording sheets are used as block copy originals and design originals which are required to have high gloss and quick drying property.
That is, when printing was performed using a conventional recording sheet having a porous ink absorbing layer provided on a support, the gloss was low due to the light scattering property of the porous ink absorbing layer, and it was not usable.

[0006]

Accordingly, the first object of the present invention is to provide good image reproducibility, fast ink drying property and very high gloss when ink jet recording is carried out. An object is to provide an excellent inkjet recording sheet. A second object of the present invention is to provide an ink jet recording sheet having excellent water resistance.

[0007]

The ink jet recording sheet of the present invention is an ink jet recording sheet in which an ink receiving layer is provided on at least one surface of a base paper mainly composed of natural pulp. Ri multilayer paper making fiberboard der produced by the gas adjustment method, and the multilayer paper making top layer of the base paper
5 hardwood bleached sulfite pulps as natural pulp
It is characterized by containing 0% by weight or more .

[0008]

The ink jet recording sheet of the present invention comprises
The ink receiving layer contains cation-modified non-spherical colloidal silica.

The ink jet recording sheet of the present invention is characterized in that the cation modifier in the non-spherical colloidal silica in which the ink receiving layer is cation modified is at least one of hydrous metal oxides of aluminum, zirconium or tin. To do.

The ink jet recording sheet of the present invention comprises a cation-modified non-spherical colloidal silica (SiO ₂
It is characterized in that the coating amount of the cation modifier with respect to (converted) is 1% by weight to 30% by weight in terms of the metal oxides thereof.

The ink jet recording sheet of the present invention is characterized in that the cation-modified non-spherical colloidal silica is acicular or fibrous.

The ink jet recording sheet of the present invention is an ink jet recording sheet in which at least one surface of a base paper mainly composed of natural pulp is coated with a resin composition, and further an ink receiving layer is provided, the base paper is made. It is a multi-layered base paper produced by the combining method and is characterized in that the pulp used in the uppermost layer is 50% by weight or more of hardwood sulfite pulp.

The ink jet recording sheet of the present invention is a multi-ply base paper coated with a resin composition, and the pulp used as the uppermost layer of the multi-ply base paper contains 50% by weight or more of hardwood bleached sulfite pulp. It is characterized by that.

The ink jet recording sheet of the present invention is characterized in that the resin of the resin composition with which the base paper is coated is a polyolefin resin.

The ink jet recording sheet of the present invention is characterized in that the polyolefin resin of the resin composition with which the base paper is coated is a polyethylene resin.

Hereinafter, the ink jet recording sheet of the present invention will be described in detail.

The term "non-spherical" as used in the present invention means that it is not substantially spherical, and needle-like or fibrous ones are preferably used. The size is preferably about several μm to 500 μm in the length direction.

The cation-modified non-spherical colloidal silica used in the practice of the present invention is coated with a hydrous metal oxide such as hydrous aluminum oxide, hydrous zirconium oxide, or hydrous tin oxide as a cation modifier. A cation-modified non-spherical colloidal silica is preferably used, and a cation-modified non-spherical aluminum hydroxide is particularly preferably used. Examples of the cation modification method include U.S. Pat. No. 3,007,878 and JP-B-47-2695.
The method described in No. 9 can be used.

The coating amount of the hydrous metal oxide as the cation modifier in the cation-modified non-spherical colloidal silica used in the practice of the present invention is silica (SiO 2).
₂ conversion) 1 wt% to 30 in terms of anhydrous metal oxide
A weight% range is useful. If the coating amount of the cation modifier is too small, the water resistance of the ink recorded image of the ink jet recording sheet will be significantly deteriorated and the gloss will be reduced, while if it is too large, the physical properties of the ink receiving layer will be poor. The range of 2.5 wt% to 25 wt% is preferable, and the range of 5 wt% to 20 wt% is particularly preferable, because it tends to become brittle and cause cracking or worsening, and the gloss tends to decrease. . Further, in the liquid of the cation-modified non-spherical colloidal silica, acetic acid for the purpose of a colloid stabilizer,
It may contain an acid component such as citric acid, sulfuric acid or phosphoric acid. Specific examples of the cation-modified non-spherical colloidal silica include ST-special modified series manufactured by Nissan Chemical Co., Ltd.

The coating amount of the cation-modified non-spherical colloidal silica contained in the ink receiving layer in the present invention is useful in the range of ^{2 to} 100 g / m ² as solid content. When the coating amount is small, the ink receptivity is poor, the dryness of the image recorded with ink is deteriorated, and the sharpness of the image is deteriorated. On the other hand, when the coating amount is too large, the ink is The coating property of the receptor layer becomes brittle, causing cracking and worsening, and gloss and transparency tend to deteriorate, and further curling properties deteriorate, so the coating amount is 4 to 50 g / m ² The range is preferably 6 to
A range of 30 g / m ² is particularly preferred.

The ink receiving layer in the present invention may contain various polymers for the purpose of improving the drying property of the ink, the film physical properties of the ink receiving layer, the gloss, the sharpness of the image and the like. Specific examples of such polymers include lime-processed gelatin, acid-processed gelatin, enzyme-processed gelatin, gelatin derivatives, and various gelatins such as gelatin reacted with an anhydride of a dibasic acid such as phthalic acid, maleic acid and fumaric acid. Ordinary polyvinyl alcohols with various saponification degrees, carboxy-modified, cation-modified and amphoteric polyvinyl alcohols and their derivatives, oxidized starch,
Starches such as cationized starch and etherified starch, cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose, polyvinylpyrrolidone, polyvinylpyridinium halide, sodium polyacrylate, methacrylic acid acrylate copolymer salt, polyethylene Glycol, polypropylene glycol, polyvinyl ether,
Alkyl vinyl ether / maleic anhydride copolymers, styrene / maleic anhydride copolymers and their salts, synthetic polymers such as polyethyleneimine, styrene / butadiene copolymers, conjugated diene copolymers such as methylmethacrylate / butadiene copolymers. Polymer latex, polyvinyl acetate, vinyl acetate / maleic acid ester copolymer,
Vinyl acetate / acrylic acid ester copolymer, ethylene /
Vinyl acetate polymer latex such as vinyl acetate copolymer, acrylic acid ester polymer, methacrylic acid ester polymer, ethylene / acrylic acid ester copolymer, styrene / acrylic acid ester copolymer, or other acrylic polymer or Copolymer latex, vinylidene chloride copolymer latex, etc., or functional group-modified polymer latex with functional group-containing monomer such as carboxyl group of these various polymers, thermosetting synthetic resin such as melamine resin, urea resin Examples thereof include water-based adhesives such as polymethylmethacrylate, polyurethane resin, unsaturated polyester resin, vinyl chloride / vinyl acetate copolymer, polyvinyl butyral, alkyd resin, and other synthetic resin adhesives, which may be used alone or in combination. Can be included . The amount of these polymers used is 2 with respect to 100 parts by weight of the solid content of the non-spherical colloidal silica which is cation-modified to meet the above purpose.
A range of up to 100 parts by weight is useful, but a range of 5 to 30 parts by weight is preferred.

The ink receiving layer in the present invention may contain various surfactants for the purpose of improving the sharpness of the image. These surfactants may be any of anionic, cationic, nonionic and betaine types, and may be low molecular weight or high molecular weight. You may contain together 1 type (s) or 2 or more types of surfactant together. Preferred specific examples of these surfactants include long-chain alkylbenzene sulfonates, long-chain, preferably anionic surfactants such as branched alkylsulfosuccinate ester salts, long-chain, preferably branched alkyl groups. Nonionic surfactants such as phenol-containing polyalkylene oxide ethers and long-chain alkyl alcohol polyalkylene oxide ethers,
Examples thereof include fluorinated surfactants described in JP-B-47-9303 and US Pat. No. 3,589,906.
The amount of the surfactant added to the ink receiving layer is preferably 0.1 to 7% by weight, more preferably 0.5 to 3% by weight, based on the dry solid weight of the ink receiving layer.

The ink receiving layer in the present invention may contain various additives in addition to the cation-modified non-spherical colloidal silica, a polymer, if necessary, and a surfactant. For example, a silane coupling agent such as γ-aminopropyltriethoxysilane and N-β (aminoethyl) γ-aminopropyltrimethoxysilane, an active halogen compound, a vinyl sulfone compound, an aziridine compound, an epoxy as a polymer hardener. Compounds, acryloyl compounds, hardeners such as isocyanate compounds, as a preservative, JP-A-1-1025
P-hydroxybenzoic acid ester compounds, benzisothiazolone compounds, isothiazolone compounds, etc. described or exemplified in JP-A No. 63-204251, JP-A No. 1-266537.
Nos. Etc. or the exemplified coloring pigments, coloring dyes, optical brighteners, etc., yellowing inhibitors such as sodium hydroxymethanesulfonate and sodium P-toluenesulfinate, and ultraviolet absorbers such as hydroxy-di-alkyl. Antioxidants such as benzotriazole compounds having a phenyl group at the 2-position, polyhindered phenol compounds described or exemplified in JP-A-1-105245, and pencil writing agents such as starch granules, barium sulfate, and silicon dioxide. Organic or inorganic fine particles having a particle diameter of 0.2 μm to 5 μm,
Organopolysiloxane compounds described or exemplified in Japanese Examined Patent Publication No. 4-1337, pH adjusting agents such as caustic soda, sodium carbonate, sulfuric acid, hydrochloric acid, phosphoric acid, citric acid, octyl alcohol, various antifoaming agents such as silicon The additives can be contained in appropriate combination.

The apparatus for applying the ink receiving layer coating liquid in the present invention includes an air knife coater, a roll coater, a bar coater, a wire bar coater, a blade coater, a slide hopper coater, a curtain coater, a gravure coater, and a flexogravure coater. And the like. Prior to coating, it is desirable that the surface of the support be subjected to activation treatment such as corona discharge treatment or flame treatment. As a drying device for the applied coating liquid, various drying devices such as a straight tunnel dryer, an arch dryer, an air loop dryer, a hot air dryer such as a sine curve air float dryer, a dryer using infrared rays, a heating dryer, a microwave, etc. Can be mentioned.

The ink receiving layer in the present invention may have a single layer structure or a multilayer structure. As an example of a multilayer structure, Japanese Patent Laid-Open No.
-89954, 60-224578, and 61-12388. For example, the ink permeable layer described in JP-A-61-12388 may be further provided on the ink receiving layer of the present invention. Further, the ink receiving layer is provided on at least one side of the support, but it may be provided on both sides of the support for the purpose of curling prevention, inkjet recording on both sides, and the like.

The base paper of the ink jet recording sheet used in the examples of the present invention is a multi-layer paper.
Preferably, a hardwood bleached sulfite pulp (hereinafter abbreviated as LBSP) is used as the uppermost natural pulp of the multi-layer paper.
Is used in an amount of 50% by weight or more. Other natural pulps include JP-A-58-73642, JP-A-60-67940, and JP-A-60-67940.
-69649, it is advantageous to use an appropriately selected natural pulp as described or exemplified in JP-A-61-35442, etc., but synthetic pulp, synthetic fiber or recycled pulp may be used if necessary. You may use. Natural pulp was subjected to usual bleaching treatment such as chlorine, hypochlorite, chlorine dioxide bleaching, alkali extraction or alkali treatment and, if necessary, oxidative bleaching treatment with hydrogen peroxide, oxygen, etc., and a combination thereof. Wood pulp of softwood pulp, hardwood pulp, mixed wood of softwood and hardwood is advantageously used, and various kinds of kraft pulp, soda pulp and softwood sulfite pulp can also be used.

By using 50% by weight or more of hardwood sulfite pulp in the uppermost layer of the multi-layered base paper of the present invention, the ink receiving layer coated thereon becomes uniform and the reproducibility of recorded images is improved. improves. The hardwood sulfite pulp gives a smooth base paper top layer, and when the ink receiving layer is applied, the top paper base layer swells less, resulting in a uniform ink receiving layer and good inkjet image reproducibility. Expected to be.

The absolute dry weight of the multilayer paper making base paper of the present invention is not particularly limited but is preferably from 30 to 250 g / m ^2, in particular absolute dry weight of the top layer is preferably from 10 to 100 g / m ^2.

The base paper of the ink jet recording sheet preferably used in the practice of the present invention may contain various additives when preparing the stock slurry. As a sizing agent, fatty acid metal salt or fatty acid, JP-B-62-753
No. 4, or an exemplified alkyl ketene dimer emulsion or epoxidized higher fatty acid amide, alkenyl or alkyl succinic anhydride emulsion, a rosin derivative, etc., as an anionic, cationic or amphoteric polyamine as a dry paper strength enhancer. Acrylamide, polyvinyl alcohol, cationized starch, vegetable galactomannan, etc., as a wet paper strength enhancer, polyamine polyamide epichlorohydrin resin, etc., as a filler, clay, kaolin, calcium carbonate, titanium oxide, etc. As a fixing agent, aluminum chloride, sulfuric acid Water-soluble aluminum salts such as bun soil, pH adjusting agents such as caustic soda, sodium carbonate, and sulfuric acid, and other color pigments or coloring dyes described or exemplified in JP-A-63-204251 and JP-A-1-266537. , An appropriate combination of optical brightener Yes it is advantageous allowed to.

The base paper of the ink jet recording sheet preferably used for carrying out the present invention may contain various water-soluble polymers, antistatic agents and additives by spraying, size press or tab size press. You can As a water-soluble polymer,
1-266537 or exemplified starch-based polymers, polyvinyl alcohol-based polymers, gelatin-based polymers, polyacrylamide-based polymers, cellulose-based polymers, etc., as antistatic agents, alkali metal salts such as sodium chloride and potassium chloride, calcium chloride , Barium chloride and other alkaline earth metal salts, colloidal silica and other colloidal metal oxides, polystyrene sulfonate and other organic antistatic agents, emulsions and latexes such as petroleum resin emulsions, ethylene-vinyl acetate copolymer Combined, as a pigment such as an emulsion or latex of a copolymer described in JP-A-55-4027 and JP-A-1-180538 or exemplified by ethylene and acrylic acid (or methacrylic acid) as at least constituents. , Clay, kaolin, talc, barium sulfate , Such as titanium oxide, pH
As a regulator, it is advantageous to contain hydrochloric acid, phosphoric acid, citric acid, caustic soda, and the like, as well as the above-mentioned coloring pigments, coloring dyes, optical brighteners, and the like in an appropriate combination.

The base paper of the ink jet recording sheet preferably used in the practice of the present invention is JIS P81.
Those having a smooth surface having a Beck's smoothness defined by 19 of 100 seconds or more are preferable, and those having a smooth surface of 200 seconds or more are more preferable. As a method for producing a base paper having a Beck smoothness of 100 seconds or more, a short-fiber smoothness is easily obtained, and a broad-leaved tree sulfite pulp having a small decrease in rigidity is used in a large amount, and a long-fiber content is reduced as much as possible by a beating machine. The beaten product is used as the uppermost layer of the multi-layer paper. Specifically, the beating of the pulp is such that the fiber length of the pulp after beating is 15 to 45% in the 42 mesh residue and the freeness is 15%.
It is preferably set to 0 to 400 CSF. Then, with respect to the stock chiller to which internal additives are added, a suitable papermaking method as described or exemplified in JP-A-58-37642, JP-A-61-260240, JP-A-61-284762, etc. Is used for multi-layer papermaking so that a uniform texture can be obtained with a paper machine normally used such as a Fourdrinier paper machine, a round net paper machine, and after the papermaking, a machine calender, a super calender, a thermal calender, etc. A base paper having a Beck's smoothness of 100 seconds or more can be produced by carrying out calendering treatment. The thickness of the base paper is not particularly limited, but the basis weight is preferably 30 to 250 g / m ² .

As the ink jet recording sheet preferably used in the practice of the present invention, it is useful that at least one surface of the base paper on which the ink receiving layer is provided is coated with a resin capable of forming a film. It is particularly preferable that both sides of the base paper are coated with a resin capable of forming a film. As the resin capable of forming a film, a thermoplastic resin such as a polyolefin resin, a polycarbonate resin, a polyester resin, or a polyamide resin is preferable, and among them, a polyolefin resin is more preferable from the viewpoint of melt extrusion coating property, and a polyethylene resin is particularly preferable. . Further, it may be coated with an electron beam curing resin described or exemplified in JP-B-60-17104.

Particularly, as the polyolefin resin coated on at least one surface of the base paper on which the ink receiving layer is provided, preferably on both surfaces of the base paper, homopolymers such as polyethylene, polypropylene, polybutene and polypentene, and ethylene-butylene are used. The copolymer is a copolymer composed of two or more α-olefins such as a copolymer and a mixture thereof, and a polyethylene resin is particularly preferable from the viewpoints of melt extrusion coating property and adhesiveness to a base paper. Examples of such polyethylene resins include low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, copolymers of ethylene and α-olefin such as propylene and butylene, carboxy modified polyethylene and the like. A mixture having various densities, melt flow rates (hereinafter simply abbreviated as MFR), molecular weights, and molecular weight distributions can be used, but usually has a density in the range of 0.90 to 0.97 g / cm ³ , MFR 0.1. ~ 50
g / 10 min, preferably MFR in the range of 0.3 to 40 g / 10 min can be advantageously used alone or as a mixture. Further, the resin may have a multi-layered structure.

As a method for coating the resin on the base paper surface of the ink jet recording sheet which is preferably used in the practice of the present invention, when the resin is a thermoplastic resin, preferably a polyolefin resin, particularly preferably a polyethylene resin, running is carried out. It is preferable to coat the thermoplastic resin composition on the base paper by a so-called melt extrusion coating method, in which the thermoplastic resin composition is cast into a film form from the slit die using a melt extrusion machine and coated. At that time, the temperature of the molten film is preferably 280 to 340 ° C. The slit die is preferably a flat die such as a T-type die, an L-type die or a fishtail type die, and the slit opening diameter is preferably 0.1 to 2 mm. Further, it is preferable that the base paper is subjected to an activation treatment such as a corona discharge treatment or a flame treatment before the base paper is coated with the resin composition. Further, as described in JP-B No. 61-42254, it is preferable to coat the resin layer on the running base paper after blowing the ozone-containing gas onto the molten resin composition on the side in contact with the base paper. Also, the table,
It is preferable that the resin layer on the back is coated on the base paper sequentially, preferably continuously, by extrusion coating, that is, a so-called tandem extrusion coating method. Further, the surface of the resin-coated paper support on which the ink receiving layer is applied can be processed to be a glossy surface, a finely rough surface described in JP-B-62-19732, a matte surface or a silk surface. The reverse resin layer on the opposite side is usually preferably processed into a matte surface. The thickness of the front and back resin layers is not particularly limited,
Generally in the range of 7 to 100 μm, preferably 10 to 50 μm
Those with a thickness in the range of m are preferred.

In the resin layer which coats the base paper of the ink jet recording sheet preferably used in the practice of the present invention,
Various additives can be contained. Japanese Examined Shoji 60-3
No. 430, Japanese Examined Sho 63-11655, No. 1-38291, No. 1
-38292, titanium oxide described or exemplified in JP-A-1-105245, white pigments such as zinc oxide, talc, calcium carbonate, stearic acid amide, fatty acid amides such as arachidic acid amide, zinc stearate, calcium stearate, Fatty acid metal salts such as aluminum stearate, magnesium stearate, zinc palmitate, zinc myristate, calcium palmitate, etc., JP-A-1-10
5245 described or exemplified hindered phenol, hindered amine, phosphorus-based, various antioxidants such as sulfur-based, cobalt blue, ultramarine blue, cerian blue, blue-based pigments and dyes such as phthalocyanine blue, cobalt violet, fast violet, Various additives such as magenta pigments and dyes such as manganese violet, fluorescent brightening agents and ultraviolet absorbers described or exemplified in JP-A-2-254440, and the like can be contained in an appropriate combination. The additives are preferably contained as a resin masterbatch or compound.

The surface of the support used in the practice of the present invention, which is opposite to the side on which the ink receiving layer is provided, is subjected to activation treatment such as corona discharge treatment or flame treatment, and thereafter, for the purpose of preventing static charge or the like. Various back coat layers can be applied. Also, the back coat layer, Japanese Patent Publication No. Sho 52-18020,
Japanese Patent Sho 57-9059, Japanese Sho 57-53940, Japanese Sho 58-56859
Inorganic antistatic agent, organic antistatic agent, hydrophilic binder, latex, curing agent, pigment, surfactant, etc. described or exemplified in JP-A No. 59-214849, JP-A No. 58-184144, etc. It can be contained in combination.

[0038]

EXAMPLES Examples will now be described in order to more specifically describe the present invention.

Examples 1 to 6 A mixture of hardwood bleached sulphite pulp and hardwood bleached kraft pulp 6: 4 was beaten to 320 ml of Canadian Standard Freeness, and 100 pulp was further added.
3 parts by weight of chaotic starch, 0.2 part by weight of anionized polyacrylamide, 0.4 part by weight of an emulsion of alkyl ketene dimer (as ketene dimer content), based on parts by weight.
A pulp slurry B was prepared in the same manner as the pulp slurry A preparation, except that 0.4 parts by weight of the polyaminopolyamide epichlorohydrin resin was added to the pulp slurry A and the hardwood bleached kraft pulp alone was used as the pulp. Continuously using a Fourdrinier paper machine, dry the bottom layer with pulp slurry B to 50 g /
m ² and as an upper layer, two-layer papermaking was performed so as to be completely dried to 50 g / m ² . The obtained wet paper is dried at 110 ° C., and subsequently 3 parts by weight of carboxy-modified polyvinyl alcohol, 0.05 part by weight of optical brightener, 0.002 part by weight of blue dye, 4 parts by weight of sodium chloride and 0.2 part of citric acid. 25 g / m ^{2 of an} impregnating liquid consisting of 1 part by weight and 93 parts by weight of water was impregnated, dried with hot air at 110 ° C., and supercalendered at a linear pressure of 90 kg / cm to produce a base paper for an ink jet recording sheet. did. The Beck's smoothness of the base paper at this time was 300 seconds.

Next, after the base paper surface (back surface) opposite to the side on which the photosensitive layer is coated is subjected to corona discharge treatment, a low density polyethylene resin (density 0.92 g / cm ³ , MFR = 2 g / 10 min). Two
5 parts by weight and high-density polyethylene resin (density 0.96 g / cm
³ , MFR = 20 g / 10 min) 75 parts by weight of a resin composition was melt-extrusion coated at a resin temperature of 320 ° C. to a thickness of 20 μm at a running speed of the base paper of 140 m / min.

Subsequently, the surface of the base paper was subjected to corona discharge treatment, and then the low density polyethylene resin (density 0.92) was applied to the surface.
Anatase type titanium dioxide surface-treated with 0 g / cm ³ , MI = 8.5 g / 10 minutes) 47.5% by weight, aluminum hydroxide (0.75% by weight relative to titanium dioxide as Al ₂ O ₃ minutes). 20 parts by weight of titanium dioxide pigment masterbatch consisting of 50% by weight of pigment and 2.5% by weight of zinc stearate, low density polyethylene resin (density 0.920 g / c
m ^3, MI = 4.5g / 10 min) 65 parts by weight of a high density polyethylene resin (density ^{0.970g / cm 3, MI = 7.0g} / 10
Min) resin composition consisting of 15 parts by weight of resin composition at a temperature of 325 ° C.
Was melt extrusion coated to a thickness of 20 μm at a running speed of the base paper of 140 m / min. The melt extrusion coating of the front and back polyethylene resins was performed by a so-called tandem method in which extrusion coating was sequentially performed. At that time, the surface of the resin layer containing the titanium dioxide pigment of the resin-coated paper was processed into a mirror surface, and the surface quality of the resin layer on the back was processed into a matte surface such as paper.

Then, after the corona discharge treatment on the back surface resin layer of the resin-coated paper, the dry weight content of gelatin: silicon dioxide matting agent (average particle diameter 2 μm) = 3: 1, which is 15% by weight of gelatin based epoxy resin. In addition to a hardening agent, a back coat coating solution containing an appropriate amount of coating aid and inorganic antistatic agent is applied at a coating amount of 3 g / m ² minutes as gelatin content to support resin-coated paper for inkjet recording sheets. Got the body

Then, the resin surface on the front side of the resin-coated paper support was subjected to corona discharge treatment, and a 5% aqueous solution of polyvinyl alcohol (saponification degree 98.5 mol%, average polymerization degree 1700) 1
6.6% by weight, 1% by weight of a 2% mixture of sulfosuccinic acid-2-ethylhexyl ester salt in methanol and water, 4.5% by weight of the following colloidal silica (A) to (E) or An inkjet receiving layer coating solution containing no pure colloidal silica and pure water with a residual weight percentage of 10 g / m ^{2 (} dry weight) was applied with a curtain coater and dried. Colloidal silica (A): Spherical colloidal silica (manufactured by Nissan Chemical Co., Ltd.) modified with about 1.5% by weight of aluminum in terms of Al ₂ O ₃ relative to silica (in terms of SiO ₂ ). Colloidal silica (B); based on spherical colloidal silica, Al ₂ O _{3 with} respect to silica (SiO ₂ conversion)
Spherical colloidal silica (manufactured by Nissan Chemical Industries, Ltd.) cation-modified with 12.5% by weight of aluminum oxide hydroxide. Colloidal silica (C); acicular colloidal silica (manufactured by Nissan Chemical Co., Ltd.). Colloidal silica (D); based on acicular colloidal silica (C), cation-modified with about 6.2% by weight of aluminum hydroxide oxide in terms of Al ₂ O ₃ based on silica (in terms of SiO ₂ ). Needle-like colloidal silica (Nissan Chemical Co., Ltd.). Colloidal silica (E); based on acicular colloidal silica (C), cation-modified with about 11.7% by weight of aluminum hydroxide oxide in terms of Al ₂ O ₃ based on silica (in terms of SiO ₂ ). Needle-like colloidal silica (Nissan Chemical Co., Ltd.).

Reference Example 7 Colloidal silica (in the same manner as in Example 6) except that the ratio of the hardwood bleached sulfite pulp to the hardwood bleached kraft pulp used as the upper layer in the preparation of the base paper of Example 1 was changed to 4: 6. E) was used to provide an ink receiving layer to prepare an inkjet recording sheet.

Example 8 A base paper was prepared in the same manner as in Example 1, and a back coat layer and an ink receiving layer were provided in the same manner as in Example 6 except that the resin coating layers on the front and back were not provided. A recording sheet was obtained.

Comparative Example 1 Instead of the base paper used in Example 1, a wet paper having a single layer and an absolute dry basis weight of 100 g / m ² was obtained by using only the pulp slurry A, and then the same procedure as in Example 1 was performed. A base paper for an inkjet recording sheet was obtained. Beck's smoothness was 200 seconds. An ink receiving layer was provided by using colloidal silica (E) in the same manner as in Example 6 except that the base paper obtained as a support was used to obtain an inkjet recording sheet.

Comparative Example 2 Instead of the base paper used in Example 1, a wet paper having a single layer and an absolute dry basis weight of 100 g / m ² was obtained by using only the pulp slurry B, and ink jet recording was carried out in the same manner as in Example 1. A base paper for a sheet for use was obtained. Beck's smoothness was 200 seconds. An ink receiving layer was provided by using colloidal silica (E) in the same manner as in Example 6 except that the base paper obtained as a support was used to obtain an inkjet recording sheet.

Then, for each of the obtained ink jet recording sheets, the Desk Writer C (HEW
Images were recorded using an inkjet printer (LETT PACKARD), and the following quality tests were performed. The results obtained are shown in Table 1.

Gloss: The gloss of the image area and non-image area of the ink jet recording sheet was visually determined.

Coating property: 2 by recording an image by ink jet recording
After 4 hours, the state of cracks in the image area and the non-image area was visually evaluated with a microscope.

Dryability: 3 by recording an image by ink jet recording
After 0 minutes, the image area was rubbed with a finger to visually determine the dryness of the image.

Image reproducibility: The image was recorded by ink jet and the reproducibility of the image was visually evaluated.

The evaluation criteria of the above quality test are as follows. A: Excellent with no problems. ◯: Good. Δ: Within the practical limit X: Inferior

[0054]

[Table 1]

From the results shown in Table 1, the base papers of Examples 1 to 8 were 2
The inkjet recording sheet according to the present invention, which is a layer,
It can be seen that the gloss, film-forming property, drying property and image reproducibility are good, and in particular, those containing cation-modified non-spherical colloidal silica in the ink receiving layer are excellent.

On the other hand, it can be seen that the ink jet recording sheets of Comparative Examples 1 and 2 in which the base paper is a single layer are particularly inferior in image reproducibility.

Examples 9 to 17 Based on the acicular acicular silica (C) used in the ink receiving layer of Example 4, the silica (SiO ₂ conversion) to Al ₂ O ₃ conversion is shown in Table 2. Needle-like colloidal silica or colloidal alumina cation-modified with the amount of hydrous aluminum hydroxide (Nissan Chemical Co., Ltd.
Example 100 was repeated except that 100) was used. The obtained results are shown in Table 2.

[0058]

[Table 2]

From the results shown in Table 2, the cation-modified non-spherical colloidal silica in the ink-receiving layer is equivalent to that of the ink jet recording sheet in terms of anhydrous metal oxide relative to silica (in terms of SiO ₂ ). 2.5% by weight in terms of performance
Is preferably in the range of 5 to 20% by weight.
It can be seen that the range is particularly preferable.

[0060]

INDUSTRIAL APPLICABILITY The present invention can provide an excellent ink jet recording sheet having high gloss, quick ink drying property, and good ink image reproducibility and film forming property.

Continuation of the front page (56) References JP-A-64-78877 (JP, A) JP-A-6-219043 (JP, A) JP-A-2-243381 (JP, A) JP-A-4-257483 (JP , A) JP 55-150370 (JP, A) JP 6-64306 (JP, A) JP 6-230517 (JP, A) JP 7-64238 (JP, A) JP 8-258400 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B41M 5/00 D21H 19/00

Claims (8)

(57) [Claims] 1. A ink jet recording sheet provided with an ink receiving layer on at least one surface of the base paper mainly composed of natural pulp, Ri multilayer paper making fiberboard der was prepared by base paper paper making combined method, and Of the uppermost layer of the multi-layer paper
50 hardwood bleached sulfite pulps as natural pulp
An ink jet recording sheet, characterized by containing at least wt . 2. The ink receiving layer is cationically modified
Characterized by containing non-spherical colloidal silica
The ink jet recording sheet according to claim 1. 3. The cation-modified non-spherical colloid
The cation modifier in the silica gel is aluminum,
At least one hydrous metal oxide of zirconium or tin
The ink jet recording sheet according to claim 2, which is a seed.
To. 4. The cation-modified non-spherical colloid
The cation modifier for silica-like silica (SiO 2 conversion)
The coating amount of 1% by weight to 3 in terms of their metal oxides
The ink jet according to claim 2 or 3, which is 0% by weight.
Sheet for recording. 5. The cation-modified non-spherical colloid
The silica-like silica is acicular or fibrous.
The ink jet recording sheet according to item 2, 3 or 4. 6. At least a base paper mainly composed of natural pulp
Also, one side is coated with a resin composition, and the ink receiving layer
In the inkjet recording sheet provided with, the base paper is
It is a multi-layer paper base paper manufactured by the papermaking method.
As a natural pulp of the top layer of the multi-layered base paper,
Containing 50% by weight or more of white sulfite pulp
Characteristic inkjet recording sheet. 7. The resin of the resin composition is a polyolefin
The ink jet recording sheet according to claim 6, which is a resin.
To. 8. The polyolefin resin is polyethylene
The ink jet recording system according to claim 7, which is a resin.
Red.