JP2000318298A - Ink jet recording sheet and method for recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording sheet for a pigment ink for obtaining an image capable of noticing for a long period for the ink and obtaining a satisfactory image. SOLUTION: The ink jet recording sheet comprises an ink receiving layer of a lower layer containing a noncrystalline silica and a water insoluble resin and an ink receiving layer of an upper layer containing a noncrystalline synthetic silica, water insoluble resin, a silanol modified polyvinyl alcohol on a support made of a resin film in such a manner that smoothness of the receiving layer of the upper layer measured according to JIS P 8119 is 5 to 40 sec. In this case, the receiving layer of the lower layer contains 20 to 50 pts.wt. of the water insoluble resin to 100 pts.wt. of the total solid amount and the receiving layer of the upper layer contains 5 to 20 pts.wt. of the water insoluble resin and 10 to 40 pts.wt. of the silanol modified polyvinyl alcohol to 100 pts.wt. of the total solid amount.

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 which is suitably used for a printer or the like for recording using a pigment ink, and which is excellent in coloring property of printed matter, surface rubbing of a printed portion and water resistance of a coating film. It is about.

[0002]

2. Description of the Related Art The technical progress of an ink jet color printer for producing a color hard copy at a high speed has made it possible to obtain a clear image and excellent print quality. Along with this, a recording material having more advanced characteristics has been required in order to further improve the print quality, saturation, appearance, and image. In particular, due to improvements in printing speed, resolution, saturation, etc., more advanced properties such as quick drying of ink, high absorption capacity, control of dot diameter and bleeding are required for recording materials, and various types of recording are required. Sheets have been developed. JP-A-55-5183, JP-A-56-148585 and the like disclose that a receiving layer made of a porous inorganic pigment is provided on a substrate in order to improve ink absorption.

On the other hand, in recent years, ink jet printers have been used for printing wide-ranging advertisements, such as posters, from conventional printing of documents and the like. Inkjet printers are very simple to operate and, unlike printing that requires plate making, are capable of printing in small quantities, making it possible to quickly print the required image in the required amount. In addition, for printing advertisements and the like, what is called a plotter or the like that can be printed in a wide width is usually used. Since these plotters are used for advertisements, images must be clearly visible even from a distance, and it is necessary to maintain clear images even in long-term posting. However, conventionally used ink-jet inks are dye inks using a dye as a color-forming component, and have a problem in that they are oxidized by ultraviolet rays, ozone, or the like in long-term display, discoloring the image and deteriorating the appearance. In order to solve such a problem, use of a pigment ink having higher light resistance than a dye ink as a plotter ink is disclosed in JP-A-9-157559 and JP-A-9-159.
No. 32740 discloses this. Dye inks develop color by "dyeing" the receiving layer with low molecular compounds, whereas pigment inks develop color by "laying" or "arranging" pigment particles on the receiving layer. When printing is performed using the dye pigment ink jet recording paper, the printed portion peels off when the printed portion is rubbed with a finger or the like, and there is a practical problem. In addition, although the coloring component is pigment particles and has excellent long-term storage properties, the conventional pigment ink jet recording paper has a low water resistance of the coating film, and if it is displayed outdoors for a long period of time, the coating film collapses due to rain or muddy water and the long-term It was not useable.

[0004]

SUMMARY OF THE INVENTION The present invention is capable of printing a high-quality image at a high speed, having a high print density, and being suitable for use in printers and plotters for recording using pigment ink. And a pigment ink jet recording sheet having excellent scratch resistance and water resistance of a coating film. Provided is an ink jet recording sheet for pigment ink which can be displayed for a long period of time and can provide a satisfactory image for pigment ink.

[0005]

Means for Solving the Problems [1] A lower ink receiving layer containing amorphous synthetic silica and a water-insoluble resin on a support made of a resin film, and an amorphous synthetic silica, a water-insoluble resin and a silanol An upper ink receiving layer containing a modified polyvinyl alcohol is provided.
9, the smoothness of the upper ink receiving layer was 5
An inkjet recording sheet having a duration of at least 40 seconds. [2] The lower ink receiving layer contains from 20 to 50 parts by weight of a water-insoluble resin based on 100 parts by weight of the total solids, and the upper ink receiving layer contains 5 to 100 parts by weight of the total solids. The ink-jet recording sheet according to [1], which contains not less than 20 parts by weight of a water-insoluble resin and not more than 10 parts by weight and not more than 40 parts by weight of a silanol-modified polyvinyl alcohol. [3] The ink jet recording sheet according to [1] or [2], wherein the upper ink receiving layer contains a cationic resin. [4] An undercoat layer containing a pigment and a water-insoluble resin is provided between the support and the lower ink receiving layer [1],
The sheet for inkjet recording according to [2] or [3]. [5] The inkjet recording sheet according to any one of [1] to [4], wherein the amorphous synthetic silica in the upper ink receiving layer has an average particle diameter of 6 μm or more and 16 μm or less.

[6] inkjet recording on the inkjet recording sheet according to any one of [1] to [5],
An inkjet recording sheet in which a transparent synthetic resin film is attached to the recorded surface. [7] An ink jet recording method for applying and recording an ink droplet containing a color pigment to the ink jet recording sheet according to any one of [1] to [5]. [8] The ink jet recording sheet according to [1], wherein the smoothness of the upper ink receiving layer measured based on JIS P8119 is 5 seconds or more and 15 seconds or less.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION A water-insoluble resin can be used as a binder for improving the water resistance of a receiving layer of a pigment ink jet recording paper. However, when printing is performed by inkjet recording having pigment particles as a coloring component, the ink that has landed on the receiving layer is repelled on the surface,
The dots become smaller and white portions are generated between the dots, and as a result, the print density tends to decrease. Although the print density tends to be improved by lowering the amount of the water-insoluble resin added, the water resistance of the coating film is reduced, which causes a practical problem.
Further, in the ink jet recording method for pigment ink, since the coloring component is solid pigment particles and the pigment particle component is present on the surface of the receiving layer, there is a problem that the printed portion is peeled off by rubbing with a finger. That is, the problem which was considered to be impossible at all in the recording with the dye ink becomes a serious problem in the recording with the pigment ink. The present inventors have studied the coating water resistance, print density, high definition of the image and the abrasion resistance of the printed portion, and as a result, by sequentially laminating a layer containing a specific resin in a specific ratio, the print density It has been found that the water resistance of the coating film can be improved without lowering the surface resistance, and that the formation of a specific surface structure can improve the abrasion resistance of the printed portion, thereby completing the present invention.

In the present invention, the smoothness of the surface of the ink receiving layer measured according to JIS P8119 is 5 seconds or more.
It is necessary to be 0 seconds or less, preferably 5 seconds to 25 seconds, more preferably 5 seconds to 15 seconds. It is not clear why an image having high definition and high resistance to rubbing of a printed portion can be obtained when the surface smoothness is within the above specific range, but it can be estimated as follows. Since the coloring component of the pigment ink is a pigment particle having a volume, it hardly enters the inside of the fine pores of the receiving layer. Therefore, the pigment component particles exist in the surface layer of the receiving layer.
Moreover, the pigment particle components are fixed only by a binder in the ink vehicle or a weak binding force such as van der Waals force between the particles, and when the printed portion is rubbed with a finger or the like, the printed portion is peeled off and the printed portion is removed. Is very poor in handling. However, if the smoothness of the receiving layer according to JIS P8119 is set to 40 seconds or less, unevenness is generated on the surface of the receiving layer, so that even if the printed portion is rubbed with a finger or the like, the image hardly peels off. Further, the smoothness of the receiving layer according to JIS P8119 is more preferably 15 seconds or less.
By adjusting the smoothness in JIS P8119 to 15 seconds or less, it is possible to completely prevent the printing portion from being removed by rubbing. On the other hand, if the smoothness in JIS P8119 is reduced to less than 5 seconds, the dot shape will be distorted. For this reason, when printing an image including halftones such as human skin, a high-definition image cannot be obtained due to the impression that the dots are crushed and the skin is rough. Conventionally, there are many recording sheets having a smooth coated surface, and there has been a problem that an image is peeled off when recording with a pigment ink.

The amorphous synthetic silica used in the ink receiving layer of the present invention is obtained by converting high-purity silica sand to sodium silicate, and then mixing sulfuric acid with the silica to form a silica sol, and three-dimensionally coagulating the silica sol. It can be obtained by a method of forming the aggregate, a method of stopping the growth of the secondary aggregate under the influence of temperature, ions, and a surfactant, and a method of sedimentation. The ink receiving layer of the present invention comprises at least two layers, and the average particle diameter of the secondary aggregate of amorphous synthetic silica contained in the upper ink receiving layer (the side to which the ink is applied) is 6 μm or more and 16 μm or less. Is preferred. When the average particle size is less than 6 μm, the ink receiving layer becomes too dense and the ink absorption speed is reduced, and the subsequently ejected ink tends to be mixed and blurred before being absorbed by the receiving layer, In addition, the smoothness according to JIS P8119 tends to exceed 40 seconds, and the required abrasion resistance may not be obtained in some cases. The method for measuring the particle size of the aggregated particles is not particularly limited, but can be measured by, for example, a Coulter counter. In a wide format plotter, the ink ejection amount is large (for example, 30 to 45 g / m ² ), and if the ink absorption speed of the recording sheet is low, the ink swims on the coated surface while the ink is absorbed, and other adjacent inks Although bleeding becomes conspicuous with the color, bleeding can be prevented by setting the average particle size to 6 μm or more. On the other hand, the average aggregated particle diameter is 16 μm
When the ratio exceeds, the ink absorption speed is good, but on the other hand, the recording density may be low because the ink easily enters between the silica particles. Also, the smoothness according to JIS P8119 tends to be less than 5 seconds, in which case the shape of the printed dot becomes distorted, and a high-definition image cannot be obtained. The silica mixed into the upper ink receiving layer may be used by mixing two or more types of silica having a particle diameter such that the average particle diameter of the secondary aggregate after mixing becomes 6 μm or more and 16 μm or less. . In the present invention, the average particle size of the amorphous synthetic silica used in all the ink receiving layers does not need to be particularly the same, and can be appropriately selected within a range that does not impair the quality of the present invention.

In the ink receiving layer of the present invention, as long as the print density and high definition which are the objects of the present invention are not impaired,
Other pigments may be added to improve coating suitability and the like. Other pigments that can be used in the ink receiving layer of the present invention include calcium carbonate, clay, calcined clay,
Diatomaceous earth, talc, aluminum oxide, magnesium aluminosilicate, magnesium carbonate, barium sulfate, zinc oxide, aluminum hydroxide, magnesium hydroxide, styrene polymer, styrene copolymer, acrylate ester polymer, acrylate ester copolymer And the like, such as organic pigments. These pigments can be used in combination of two or more as necessary.

By adding a cationic resin to each ink receiving layer of the present invention, a clear image having high print density and no bleeding can be obtained. It is particularly preferable to add it to the upper layer. As the cationic resin used in the ink receiving layer of the present invention, polyethylene imine, polyvinyl pyridine,
Polydialkylaminoethyl methacrylate, polydialkylaminoethyl acrylate, polydialkylaminoethyl methacrylamide, polydialkylaminoethyl acrylamide, polyepoxyamine, polyamidoamine, dicyandiamide-formalin condensate, dicyandiamide polyalkyl-polyalkylenepolyamine condensate, polydiallyl Examples thereof include compounds such as dimethylammonium salt, polyvinylamine, and polyallylamine, and modified products thereof. Although not particularly limited in the present invention, the amount of the cationic resin contained in the ink receiving layer of the present invention is at least 3 parts by weight based on 100 parts by weight of the total solid content in each layer of the ink receiving layer. It is preferably at most 30 parts by weight. If the amount of the cationic resin is less than 3 parts by weight, the bleeding improvement effect may be insufficient. On the other hand, if the amount exceeds 30 parts by weight, the printing density may be improved, but the drying property of the ink may be reduced. .

The upper ink receiving layer of the present invention preferably contains water-insoluble resin in an amount of 5 to 20 parts by weight based on 100 parts by weight of the total solid content, whereby the adhesion to the lower ink receiving layer is improved. The water resistance between the ink receiving layers from the upper layer to the lower layer is improved. If the amount of the water-insoluble resin added to the upper ink receiving layer is less than 5 parts by weight, the adhesion to the lower ink receiving layer may be reduced and the water resistance of the coating film may be reduced. On the other hand, if the addition amount exceeds 20 parts by weight, the landed ink may be repelled on the surface of the receiving layer, and the dots may be reduced to lower the print density. Examples of the water-insoluble resin used in the ink receiving layer of the present invention include conjugated diene polymer latex such as styrene-butadiene copolymer and methyl methacrylate-butadiene copolymer, and polymers or copolymers of acrylate and methacrylate. Water-insoluble resins such as an acrylic polymer latex such as a polymer and a vinyl polymer latex such as a vinyl acetate copolymer can be used. One or more of these water-insoluble resins can be appropriately selected and used as needed.

By including silanol-modified polyvinyl alcohol in the upper ink receiving layer, the landed dots can be spread, the print density can be improved, and a receiving layer having a stronger coating film can be obtained. The amount of the silanol-modified polyvinyl alcohol is preferably from 10 to 40 parts by weight based on the total solid content of the upper layer. Although it is not clear why the printing density is improved by including the silanol-modified polyvinyl alcohol in the upper ink receiving layer of the present invention, it can be estimated as follows. Silanol-modified polyvinyl alcohol is a polyvinyl alcohol-based polymer obtained by radically copolymerizing an alkylene monomer containing a silanol group with a lower fatty acid vinyl ester such as vinyl acetate, and saponifying the obtained copolymer. .
Silanol-modified polyvinyl alcohol is hydrophilic because it contains a highly polar hydroxyl group in the molecule. However, silanol-modified polyvinyl alcohol has silanol groups, and forms a strong chemical bond with other silanol groups within a molecule or between molecules. I have. That is, while the silanol-modified polyvinyl alcohol is hydrophilic, it hardly dissolves in cold water. Therefore, the silanol-modified polyvinyl alcohol does not absorb the ink due to the swelling of the resin in the receiving layer, but has a property of taking in the ink by a capillary phenomenon like the pigment. By containing silanol-modified polyvinyl alcohol in the upper ink receiving layer, the ink that lands on the surface of the receiving layer spreads in the horizontal and vertical directions due to the capillary action of amorphous synthetic silica and silanol-modified polyvinyl alcohol, and as a result, the dots spread It can be estimated that the print density is improved.

When the addition amount of the silanol-modified polyvinyl alcohol contained in the upper ink receiving layer of the present invention is less than 10 parts by weight, the binder component of the ink receiving layer is reduced, the strength of the coating film is reduced, and powders such as powder dropping are reduced. Problems may occur. On the other hand, if the amount of polyvinyl alcohol exceeds 40 parts by weight, the size of the landed dots becomes too large, and bleeding may occur. The polymerization degree of the silanol-modified polyvinyl alcohol used in the present invention is 500
It is preferably at least 2,000. If the polymerization degree is less than 500, the strength of the coating film may decrease, and if it exceeds 2,000, the viscosity of the coating material may increase, and a problem may occur in the coating suitability.

It is also possible to add a water-soluble resin to the lower and upper ink receiving layers for the purpose of improving coating suitability and the like as long as the quality of the present invention is not impaired. As the water-soluble resin, polyvinyl alcohol derivatives such as polyvinyl alcohol and cation-modified polyvinyl alcohol,
Water-soluble polymer binders such as proteins such as casein, derivatives such as starch and oxidized starch, and cellulose derivatives such as polyvinylpyrrolidone and carboxymethylcellulose can be exemplified. One or more of these binders can be appropriately selected and used as needed. In addition, pigment dispersants, defoamers, viscosity modifiers, crosslinking agents,
A fluorescent dye or the like is appropriately used depending on the production conditions and required performance.

The ink receiving layer of the lower layer of the present invention (the ink receiving layer which is closer to the support) contains a water-insoluble resin and amorphous synthetic silica, and contains other pigments, cationic resins, auxiliaries and the like. Can be contained. Although the particle size of the amorphous synthetic silica in the lower layer is not particularly limited, it is about 1 to 40 μm. Water-insoluble resin is added to the lower ink receiving layer in a total solid content of 10
By containing 20 parts by weight or more and 50 parts by weight or less with respect to 0 parts by weight, the adhesion between the undercoat layer and the lower ink receiving layer is improved, and the water resistance between the undercoat layer and the ink receiving layer is improved. When the amount of the water-insoluble resin added to the lower ink-receiving layer is less than 20 parts by weight, the water resistance is reduced.
On the other hand, if the addition amount exceeds 50 parts by weight, the ink absorbency of the receiving layer is reduced and bleeding occurs.

The method for providing the ink-receiving layer on the support is not particularly limited, and a conventionally known coating machine such as a bar coater, an air knife coater, a blade coater, a die coater, a curtain coater or the like can be used. Can be provided.

The coating amount of the upper and lower ink receiving layers obtained in the present invention is determined by the final use, and does not need to be increased unnecessarily as long as the ink absorbency, color development and coating strength are satisfied. The coating amount of the lower ink receiving layer obtained in the present invention is 3 g / m ² or more and 10 g as a dry weight.
/ M ² or less is more preferable. If the ink receiving layer is less than 3 g / m ^2, bleeding may occur due to insufficient ink absorption capacity. Conversely, if the coating amount exceeds 10 g / m ² , the strength of the coating film may decrease.

The coating amount of the upper ink-receiving layer obtained in the present invention is determined by the final use, and need not be unnecessarily increased as long as the ink absorbency, coloring property and coating strength are satisfied. 3 g / m ² or more, 30 g / m ²
It is appropriately selected and used from the following ranges. If the amount of the ink receiving layer is less than 3 g / m ² , the ink absorption capacity is often insufficient, and the image starts to flow or color bleeds, resulting in blurred image. However, when an ink receiving layer exceeding 30 g / m ² is provided, since the upper ink receiving layer is thick, the adhesiveness to the lower ink receiving layer is weakened, and the surface strength of the finished pigment ink jet recording sheet may be weakened. There is. Further, the cost is high.

In the present invention, an undercoat layer containing a water-insoluble resin is appropriately provided between the support and the lower ink-receiving layer to thereby provide an ink-jet ink having good adhesion between both layers and excellent water resistance of the coating film. A recording sheet can be obtained. When the undercoat layer does not contain a water-insoluble resin and is mainly composed of a water-soluble resin, if the surface of the ink-receiving layer wet with water is rubbed, the ink-receiving layer often easily peels off. Further, even if a transparent resin film is bonded to the surface of the ink receiving layer in order to avoid getting wet with water, it is inevitable that water enters from the end. If a water-soluble adhesive, such as low molecular weight polyvinyl alcohol, is included relatively easily, if the time of contact with water is short, the adhesive dissolved with water that has entered from the end may not be used. It becomes a highly viscous liquid, so that further entry of water can be suppressed. However, for example, if you are exposed to rain for a long time outdoors, for example, because of the long contact time with water,
Eventually, the penetration of water cannot be suppressed, and as a result, the ink receiving layer is peeled off together with the transparent resin film. Therefore, in applications where water resistance is required, it is preferable that the undercoat layer contains a water-insoluble resin and, in addition to this, a transparent resin film is attached to the surface of the ink receiving layer after inkjet recording.

Examples of the water-insoluble resin used in the undercoat layer include a conjugated diene polymer latex such as a styrene-butadiene copolymer and a methyl methacrylate-butadiene copolymer, and a polymer of an acrylic acid ester and a methacrylic acid ester. Water insolubility such as acrylic polymer latex such as copolymer, vinyl polymer latex such as vinyl acetate copolymer, or modified polymer latex containing functional groups such as carboxyl group and cationic group of these various polymers Resins can be exemplified. These water-insoluble resins usually have a total solids content of the undercoat layer of 10%.
The dry weight is preferably in the range of 10 to 100 parts by weight, more preferably 20 to 80 parts by weight, based on 0 parts by weight. These water-insoluble resins may be used as needed.
It is also possible to use more than one species in combination.

A pigment can be added to the undercoat layer together with the water-insoluble resin, and calcium carbonate, clay, calcined clay, diatomaceous earth, talc, aluminum oxide, silica,
White carbon, magnesium aluminosilicate, magnesium carbonate, barium sulfate, titanium oxide, zinc oxide,
Aluminum hydroxide, magnesium hydroxide, styrene polymer, styrene copolymer, acrylate polymer,
Materials such as organic pigments (plastic pigments) such as acrylate copolymers are exemplified. These pigments can be used in combination of two or more as necessary.

A water-soluble resin may be added to the undercoat layer of the present invention in order to improve the pigment dispersibility and coatability within a range that does not impair the water resistance and strength of the coating film, which is the object of the present invention. good. A water-soluble resin may be added to the undercoat layer, and examples thereof include polyvinyl alcohol and polyvinyl alcohol derivatives such as silyl-modified polyvinyl alcohol and cation-modified polyvinyl alcohol, proteins such as casein, and derivatives such as starch and oxidized starch. One or more of these water-soluble resins can be appropriately selected and used as necessary.

In addition, a pigment dispersant, an antifoaming agent, a viscosity modifier, a cross-linking agent, and the like are appropriately used as additives according to production conditions and required performance. JIS P 8 for undercoat layer
The water repellency of R6 or more based on the method described in 137 is preferable because an undercoat layer having more excellent water resistance can be obtained. When the water repellency of the undercoat layer is less than 6, the water absorption of the undercoat layer is increased, and it may be difficult to obtain the required coating film water resistance.
The method of providing the undercoat layer on the support is not particularly limited, and can be provided by a conventionally known coating machine such as a bar coater, an air knife coater, a blade coater, and a curtain coater. . The coating amount of the undercoat layer obtained in the present invention is determined by the final use, and it is not necessary to increase the coating amount unnecessarily as long as the coating film water resistance, recording characteristics, storage stability, etc. are satisfied, and 0.2 g / m ² The range is preferably 10.0 g / m ² or less. If the coating amount of the undercoat layer is small, the adhesiveness to the support may be slightly low, and poor water resistance of the coating film may occur. Also, if the amount of the undercoat layer applied is large, fine circular defects may occur on the surface of the ink receiving layer applied on the undercoat layer, which may impair the appearance of the recording paper.

Examples of the resin film used for the support of the present invention include thermoplastic resins such as polyester resins and olefin resins. These provide a recording medium having excellent water resistance. Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, and polycyclohexene terephthalate, and examples of the olefin resin include polyethylene, polypropylene, an ethylene-propylene copolymer, an ethylene-vinyl acetate copolymer, or a mixture of these as a main component. Can be exemplified. In addition, one or more of these thermoplastic resins can be appropriately selected and used, and polystyrene, a (meth) acrylate copolymer, or the like can be used as a mixture of other thermoplastic resins. Further, a film formed by stretching these thermoplastic resins in the longitudinal and / or transverse directions may be used. A paper-like material (synthetic paper) in which fine holes are formed inside the resin film can also be used. For example, a substance which is easily dissolved in the film is kneaded and eluted to form a microporous one, a microporous one formed by a foaming agent, and the like, and a film obtained by mixing an inorganic fine powder in the thermoplastic resin. It may be formed into a paper-like layer by, for example, performing a uniaxial stretching treatment or a biaxial stretching treatment to form micropores therein. In the present invention, using a multilayer film obtained by laminating a plurality of such films as a support, for example, a two- or three-layer film provided with a base material layer and a paper-like layer on both sides or one side, Alternatively, a three- to five-layer film having a surface layer formed on at least one surface of a paper-like layer may be used. A film in which a thermoplastic resin has a paper-like layer is generally known as a synthetic paper. Also,
The opacity of such a film is not particularly limited in the present invention.

As the recording liquid (ink) applied to the recording paper of the present invention, those containing a coloring pigment as a color-forming component are preferable to dye inks because of their excellent weather resistance. The recording liquid is
An organic or inorganic pigment particle component is dispersed in an aqueous or non-aqueous solvent. Examples of organic pigments include azo, phthalocyanine, perlin, isoindolinone, imidazolone, pyranthrone, and thioindigo pigments.Examples of inorganic pigments include carbon black, synthetic iron oxide yellow, and transparent pigments. Pigments such as red iron, titanium yellow, molybdate orange, cuprous oxide, cobalt blue and ultramarine blue can be exemplified. When dispersing these color pigments, various surfactants, low molecular weight dispersants, and resin compounds having a hydrophilic functional group and a hydrophobic functional group are used as a dispersant. The color pigment and the dispersant are mixed in a solution, and the mixture is pulverized into fine dispersed particles using a disperser such as a paint shaker or a sand mill, and coarse particles are filtered with a filter having a pore size of 1.0 μm or less to obtain a pigment ink. That is usually done.

After printing on the recording paper of the present invention with a printer,
In order to further increase water resistance and light resistance, over lamination may be performed. As the over-laminated paper, one obtained by applying an adhesive to a transparent base material is used. As the transparent substrate, films of polyolefins represented by polyethylene, polypropylene, etc., polyesters represented by polyethylene terephthalate, and polyvinyls represented by polyvinyl chloride are preferably used. The thickness of the transparent substrate is 30 to 200 μm, preferably 50 to 150 μm. If it is too thin, wrinkles are likely to occur during bonding, and if it is too thick, it is difficult to handle and workability is poor. These films include benzophenones represented by 2-hydroxybenzophenone, 2,4-dihydroxybenzophenone, 2,2 ′, 4-trihydroxybenzophenone, and (2-hydroxyphenyl) in order to further increase light resistance. Benzotriazole, (2-hydroxyphenyl-
An ultraviolet absorber such as benzotriazoles represented by 5-methylphenyl) benzotriazole may be contained. As the adhesive, a heat-sealing type or pressure-sensitive adhesive type resin is suitably used. Styrene for resin
From those of butadiene type, acrylic type, urethane type etc.,
Although it can be appropriately selected according to the purpose, an acrylic adhesive is preferably used in view of a wide range of performance and economy. Acrylic adhesive is ethylene acrylic,
A copolymer of an acrylic monomer such as methyl methacrylate, ethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, N-methylol acrylamine and an ethylene monomer or styrene monomer copolymerizable therewith can be used. .

[0028]

EXAMPLES The present invention will be described more specifically with reference to the following examples, but it should be understood that the present invention is not limited by these examples. In the following, parts and% all indicate parts by weight and% by weight. "Preparation of coated sheet for undercoat layer" 60 parts of calcium carbonate (oil absorption: 60 ml / 100 g, trade name: Callite SA, manufactured by Shiroishi Central Research Institute), acrylic emulsion (glass transition temperature: 0 degrees, trade name: AE-322) , Manufactured by Nippon Synthetic Rubber Co., Ltd.), and water was added to the composition so as to have a concentration of 50%, mixed and stirred to obtain an undercoat layer paint.

The above-mentioned paint is a multi-layer film-processed synthetic paper (trade name: YUPO FPG-80) in which a paper-like layer (containing microporous material) formed by adding an inorganic pigment to polypropylene and forming a stretched film is provided on the front and back surfaces. , 80 μm thick, made of Oji Yuka Synthetic Paper) has a coating weight after drying of 5.0 g / m ^2.
And dried at 110 ° C. to prepare a white undercoat layer coated sheet. "Preparation of Coating Sheet for Lower Ink Receiving Layer" 20 parts of polyvinyl alcohol (trade name: polyvinyl alcohol 117, manufactured by Kuraray) are added to 400 parts of water, and stirred while heating to 90 ° C. to dissolve the polyvinyl alcohol in water. Let it. This solution was mixed with amorphous synthetic silica (trade name: Nipseal RS-150, manufactured by Nippon Silica Industry, average particle size).
0 μm) and 40 parts of vinyl acetate-ethylene latex (trade name: Sumikaflex S-470, manufactured by Sumitomo Chemical)
30 parts and polydiallyldimethylammonium chloride (trade name: Unisense CP-103, manufactured by Senka) 10
Were mixed and stirred to obtain a paint for the first layer of the ink receiving layer.
The above-mentioned paint is applied on the undercoat layer of the undercoat layer-coated sheet with a bar coater so that the coating weight after drying is 8.0 g / m ^2, and dried at 110 ° C. to give a white color. An ink receiving layer first layer coating sheet was prepared.

"Preparation of upper ink receiving layer" Silanol-modified polyvinyl alcohol (trade name: R-1130,
30 parts of Kuraray (made by Kuraray Co., Ltd.) are added to 400 parts of water, and stirred while heating to 90 ° C. to dissolve the silanol-modified polyvinyl alcohol in water. To this solution, 50 parts of amorphous synthetic silica (trade name: Nipseal RS-150, manufactured by Nippon Silica Industries, average particle size: 15.0 μm) and vinyl acetate-
Ethylene latex (trade name: Sumikaflex S-
470, manufactured by Sumitomo Chemical Co., Ltd. and 10 parts of polydiallyldimethylammonium chloride (trade name: Unisense CP-10)
3, manufactured by Senka Co., Ltd.) and stirred to obtain an ink-receiving layer paint. 9. The coating weight after drying the upper ink receiving layer coating composition on the lower ink receiving layer coating sheet is 10.
0 g / m ² with a bar coater.
Dried at ℃ to make white pigment inkjet recording sheet

Example 2 Amorphous fine silica used for the lower ink receiving layer (first layer) and the upper ink receiving layer (second layer) was replaced with amorphous synthetic silica (trade name: Nipseal ER, Except that the average particle size was 11.0 μm, manufactured by Nippon Silica Kogyo Co., Ltd.
A pigment ink jet recording sheet was obtained in the same manner as in Example 1. Example 3 Amorphous fine silica used for the lower ink receiving layer (first layer) and the upper ink receiving layer (second layer) was replaced with amorphous synthetic silica (trade name: Carplex # 80, Shionogi) Pharmaceutical, average particle size 8.1 μm) except that
A pigment ink jet recording sheet was obtained in the same manner as in Example 1.

Example 4 Amorphous fine silica used for the lower ink receiving layer (first layer) and the upper ink receiving layer (second layer) was replaced with amorphous synthetic silica (trade name: Nip Seal L300, A pigment ink jet recording sheet was obtained in the same manner as in Example 1, except that the average particle diameter was changed to 7.0 μm, manufactured by Nippon Silica Industry. Example 5 Vinyl acetate-ethylene latex (trade name: Sumikaflex S) used for the lower ink receiving layer (first layer)
-470, manufactured by Sumitomo Chemical Co., Ltd.) A pigment ink jet recording sheet was obtained in the same manner as in Example 2, except that 30 parts was changed to 15 parts.

Example 6 Vinyl acetate-ethylene latex (trade name: Sumikaflex S) used for the lower ink receiving layer (first layer)
-470, manufactured by Sumitomo Chemical Co., Ltd.) A pigment ink jet recording sheet was obtained in the same manner as in Example 2, except that 30 parts was changed to 55 parts. Example 7 Vinyl acetate-ethylene latex (trade name: Sumikaflex S) used for the upper ink receiving layer (second layer)
-470, manufactured by Sumitomo Chemical Co., Ltd.) A pigment ink jet recording sheet was obtained in the same manner as in Example 2 except that 10 parts was changed to 7 parts.

Example 8 Vinyl acetate-ethylene latex (trade name: Sumikaflex S) used for the upper ink receiving layer (second layer)
-470, manufactured by Sumitomo Chemical Co., Ltd.) A pigment ink jet recording sheet was obtained in the same manner as in Example 2, except that 10 parts was changed to 17 parts. Example 9 In the same manner as in Example 2, except that 30 parts of silanol-modified polyvinyl alcohol (trade name: R-1130, manufactured by Kuraray) used for the upper ink receiving layer (second layer) was changed to 25 parts. A pigment ink jet recording sheet was obtained.

Example 10 Silanol-modified polyvinyl alcohol (trade name: R-1130, used for the upper ink receiving layer (second layer))
Example 2 except that 30 parts were changed to 45 parts (made by Kuraray)
In the same manner as described above, a pigment ink jet recording sheet was obtained. Comparative Example 1 Amorphous fine silica used for the lower ink receiving layer (first layer) and the upper ink receiving layer (second layer) was replaced with amorphous synthetic silica (trade name: Nipsil VN3, Nippon Silica Industry) Pigment inkjet recording sheet was obtained in the same manner as in Example 1, except that the average particle diameter was changed to 18.0 μm. Comparative Example 2 The amorphous fine silica used for the lower ink receiving layer and the upper ink receiving layer was changed to amorphous synthetic silica (trade name:
Fine Seal X-45, manufactured by Tokuyama, average particle size
Pigment inkjet recording sheet was obtained in the same manner as in Example 1 except that the thickness was changed to 4.3 μm.

Comparative Example 3 The amorphous fine silica used for the lower ink receiving layer (first layer) and the upper ink receiving layer (second layer) was replaced with amorphous synthetic silica (trade name: Fine Seal X). -80, manufactured by Tokuyama Co., Ltd., except that the average particle diameter was changed to 2.5 μm) to obtain a pigment ink jet recording sheet in the same manner as in Example 1. Example 11 Vinyl acetate-ethylene latex (trade name: Sumikaflex S-470, used for the first layer of the ink receiving layer)
A pigment ink jet recording sheet was obtained in the same manner as in Example 2, except that 30 parts of Sumitomo Chemical Co., Ltd. was changed to 15 parts.

Example 12 Vinyl acetate-ethylene latex (trade name: Sumikaflex S-470, used for the first layer of the ink receiving layer)
A pigment ink jet recording sheet was obtained in the same manner as in Example 2, except that 30 parts was changed to 85 parts (manufactured by Sumitomo Chemical). Example 13 Vinyl acetate-ethylene latex (trade name: Sumikaflex S) used for the upper ink receiving layer (second layer)
-470, manufactured by Sumitomo Chemical Co., Ltd.) A pigment ink jet recording sheet was obtained in the same manner as in Example 2 except that 10 parts was changed to 3 parts.

Example 14 Vinyl acetate-ethylene latex (trade name: Sumikaflex S-470, used for the second layer of the ink receiving layer)
A pigment ink jet recording sheet was obtained in the same manner as in Example 2 except that 10 parts was changed to 25 parts. Example 15 Silanol-modified polyvinyl alcohol used for the ink receiving layer second layer (trade name: R-1130, manufactured by Kuraray)
A pigment ink jet recording sheet was obtained in the same manner as in Example 2, except that 30 parts was changed to 15 parts.

Example 16 Silanol-modified polyvinyl alcohol used for the ink receiving layer second layer (trade name: R-1130, manufactured by Kuraray)
A pigment ink jet recording sheet was obtained in the same manner as in Example 2, except that 30 parts was changed to 55 parts.

Comparative Example 4 Vinyl acetate used for the first layer (lower layer) of the ink receiving layer
A pigment ink jet recording sheet was obtained in the same manner as in Example 2, except that 30 parts of ethylene-based latex was not added.

Comparative Example 5 Vinyl acetate used for the second layer (upper layer) of the ink receiving layer
A pigment ink jet recording sheet was obtained in the same manner as in Example 2 except that 10 parts of an ethylene-based latex was not added. Comparative Example 6 Except that 30 parts of silanol-modified polyvinyl alcohol used for the ink receiving layer second layer (upper layer) was not added,
A pigment ink jet recording sheet was obtained in the same manner as in Example 2.

The smoothness, scratch resistance, image quality, coating film strength, coating film water resistance, printing bleeding, printing density, surface strength, and appearance of each type of the obtained sheets were evaluated by the following methods. Table 1 shows the results.

(Smoothness) The smoothness of the coating layer surface was measured using a Beck tester according to the method described in JIS P8119. (Scratch resistance) inkjet plotter (Design Jet
2500CP: Hewlett-Packard Company)
V Ink (Pigment ink manufactured by Hewlett-Packard)
1 hour after printing in the 100% black printed area, rubbed with a cotton swab to observe the peeling of the ink from the printed area, and organoleptically evaluated the scratch resistance of the printed area.も の indicates that there was no peeling of the ink from the printed portion, ○ indicates that there was almost no peeling, X indicates that peeling was observed, and XX indicates that the peeling was even worse.

(Image quality) Ink jet plotter (Desi
gn Jet 2500CP: Hewlett-Packard Co., Ltd., and high-definition color digital standard image data (ISO / JIS) issued by the Japan Standards Association using UV ink (Hewlett-Packard Co., Ltd. pigment ink).
-SCID) image sample N1 (portrait) was printed, the image was observed, and the fineness of the image was sensory evaluated. ◎ indicates that the skin color portion of the person's face is reproduced and is excellent, も の indicates that the reproducibility of the skin color portion is good, x indicates that the reproducibility is poor.
Further poor ones are indicated by XX. (Coating film strength) The state of the coating film when the surface of the coating layer was rubbed with a cotton swab 20 times was subjected to a sensory evaluation.も の indicates that the surface of the coating layer did not peel at all, ○ indicates that the surface of the coating layer hardly peeled, △ indicates that the surface slightly peeled, but did not cause any practical problem, and X indicates that the peeling was observed and was defective.

(Water resistance of coating film) After immersion in water for 1 hour, the surface of the coating layer was rubbed with a cotton swab 20 times, and the state of the coating film was organoleptically evaluated.も の indicates that the surface of the coating layer did not peel at all, 、 indicates that the coating layer was slightly peeled but was good, △ indicates that the coating layer had no practical problem, and X indicates that the peeling was extremely poor. (Print bleeding) Inkjet plotter (Design Je
t 2500CP: Hewlett-Packard Company)
V Ink (Pigment ink manufactured by Hewlett-Packard)
Was used to perform a sensory evaluation of bleeding after printing in a 200% multicolor printing portion of 100% cyan and 100% magenta.も の indicates that there was no bleeding, な く indicates that there was no bleeding and was good, △ indicates that there was no practical problem but bleeding was observed, and X was further poor.

(Print Density) Using an inkjet plotter (Design Jet 2500CP: manufactured by Hewlett-Packard Company), printing was performed using UV ink (Pigment ink manufactured by Hewlett-Packard Company). Macbeth densitometer (RD-9, manufactured by Macbeth)
14 type).

[0047]

[Table 1]

Example 17 On an ink jet recording sheet obtained in the same manner as in Example 3, printing was performed using an ink jet plotter. That is, an ink jet plotter (design jet 250) using UV ink (Hullet Packard, pigment ink).
(0CP, manufactured by Hulet Packard Co., Ltd.). An 80-μm-thick transparent vinyl chloride film coated with an acrylic adhesive was overlaminated on this surface. Evaluation was performed in the same manner as in Example 3. Example 18 An ink-jet plotter was used to print on an ink-jet recording sheet obtained in the same manner as in Example 3. That is, an ink jet plotter (design jet 250) using UV ink (Hullet Packard, pigment ink).
(0CP, manufactured by Hulet Packard Co., Ltd.). On this surface, an acrylic adhesive was applied to a transparent vinyl chloride film containing an ultraviolet absorbing material having a thickness of 80 μm, and the laminate was overlaminated. Evaluation was performed in the same manner as in Example 3.

Example 19 On an ink jet recording sheet obtained in the same manner as in Example 3, printing was performed using an ink jet plotter. That is, an ink jet plotter (design jet 250) using UV ink (Hullet Packard, pigment ink).
(0CP, manufactured by Hulet Packard Co., Ltd.). On this surface, a transparent polyester film containing a 50 μm-thick ultraviolet absorber and coated with an acrylic adhesive was overlaminated. Evaluation was performed in the same manner as in Example 3. Comparative Example 7 An ink-jet plotter was used to print on an inkjet recording sheet obtained in the same manner as in Comparative Example 4. That is, an ink jet plotter (design jet 250) using UV ink (Hullet Packard, pigment ink).
(0CP, manufactured by Hulet Packard Co., Ltd.). On this surface, a transparent polyester film containing a 50 μm-thick ultraviolet absorber and coated with an acrylic adhesive was overlaminated. Evaluation was performed in the same manner as in Example 3. The smoothness after overlamination was 250 seconds in Example 17, 250 seconds in Example 18, 300 seconds in Example 19, and 300 seconds in Comparative Example 7. The sheet over-laminated after recording has significantly improved water resistance. Another advantage is that the recording density can be seen visually. Therefore, it can be used outdoors for display, so that it will not be adversely affected by rain. However, as shown in Comparative Example 7, even if over-lamination is performed, the water resistance of the recording layer itself is poor when the water resistance is poor.

[0050]

[Table 2]

[0051]

As is clear from Tables 1 and 2, the pigment ink-jet recording sheet obtained by the method of the present invention has abrasion resistance after ink-jet printing, image quality, coating film strength, coating film water resistance, It was confirmed that the quality of printing bleeding, printing density, and surface strength was excellent. The pigment inkjet recording sheet of the present invention has excellent image quality, coating strength, coating water resistance, print bleeding, print density, and surface strength,
Since the abrasion resistance after the pigment ink jet printing is good, there is an effect that the ink is not peeled off from the printing portion after the pigment ink printing, and that the hard handling is possible.

Claims (7)

[Claims] 1. An ink receiving layer comprising an amorphous synthetic silica and a water-insoluble resin, and an upper layer comprising an amorphous synthetic silica, a water-insoluble resin and a silanol-modified polyvinyl alcohol. An ink jet recording sheet provided with the above ink receiving layer, wherein the smoothness of the upper ink receiving layer measured according to JIS P8119 is 5 seconds or more and 40 seconds or less. 2. A method according to claim 1, wherein the lower ink receiving layer has a total solid content of 100%.
20 parts by weight or more and 50 parts by weight or less of a water-insoluble resin, and the upper ink receiving layer has a total solid content of 10 parts by weight or less.
2. The ink jet recording sheet according to claim 1, comprising 5 to 20 parts by weight of a water-insoluble resin and 10 to 40 parts by weight of a silanol-modified polyvinyl alcohol per 0 parts by weight. 3. The ink jet recording sheet according to claim 1, wherein the upper ink receiving layer contains a cationic resin. 4. The ink jet recording sheet according to claim 1, wherein an undercoat layer containing a pigment and a water-insoluble resin is provided between the support and the lower ink receiving layer. 5. The ink-jet recording sheet according to claim 1, wherein the amorphous synthetic silica in the upper ink receiving layer has an average particle diameter of 6 μm or more and 16 μm or less. 6. An ink jet recording sheet obtained by ink jet recording on the ink jet recording sheet according to any one of claims 1 to 5, and bonding a transparent synthetic resin film to the recorded surface. 7. An ink jet recording method for recording by applying ink droplets containing a color pigment to the ink jet recording sheet according to claim 1, 2, 3, 4 or 5.