JP2001246830A - Ink jet recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording sheet rapidly absorbing ink for ink jet recording, generating no blur of ink, capable of imparting an image of high water resistance and having high ink density and high gloss and inexpensive to manufacture. SOLUTION: In the ink jet recording sheet wherein an ink receiving layer is provided on a thermoplastic resin film, the ink receiving layer contains silica fine particles obtained by grinding silica manufactured by a gel method and having a mean particle size of 100-350 nm and a specific surface area (BET method) of 150 m2/g or more and a binder resin and a P/B ratio (a weight ratio of silica fine particles/binder resin) is 3-5.

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 paper which can rapidly absorb ink, does not cause bleeding, has good water resistance, and can give a high gloss image with a high ink density. Things.

[0002]

2. Description of the Related Art Ink jet recording is a non-contact type recording method using an aqueous ink. In recent years, its high speed, low noise, ease of multicolor printing, great flexibility of recording patterns, development, It is characterized by the fact that fixing is not required, and is rapidly spreading in various applications, such as a hard copy device for color graphic information including kanji. Furthermore, in recent years, the speed of ink-jet printing has been increased and the definition has been advanced, and an image formed by an ink-jet method is not inferior to that of ordinary multi-color printing, for example, by offset printing. Because the inkjet printing method is cheaper than the plate making method, there has been a movement to apply the ink jet printing method not only to simple printing but also to the fields of multicolor printing and color photography.

[0003] With the development of such an ink jet printer device, at the same time, higher characteristics are required for a recording medium. For example, when considering the use of large posters and outdoor signboards, in addition to the water-based ink absorbency of the recording medium, water resistance in the sense that the printed portion does not disappear even in bad weather, and when the medium is pulled by wind etc. However, it is also required to have durability such as not to be broken. In addition, when a photograph output application such as outputting a photograph taken by a digital camera is taken into consideration, the recording medium is required to have high glossiness in addition to the water-based ink absorbency, from the viewpoint of the sense of quality of the printed matter.

[0004] Paper using pulp papermaking as a support for the above-mentioned ink jet paper has the problem that the support itself is easily torn, although it is absorptive. It has been proposed to use a biaxially stretched polyethylene terephthalate film as a highly durable support or to use synthetic paper made of a stretched resin film containing inorganic fine powder, but the support has no water-based ink absorbency. It is necessary to provide an ink receiving layer having high water-absorbing property. In order to satisfy the ink absorbency, a technique of blending an inorganic fine powder with a water-soluble or water-dispersible resin binder constituting the ink receiving layer (Japanese Patent Application Laid-Open No. 55-51683)
Japanese Patent Application Laid-Open No. 7-89216), however, using this technique, the smoothness of the surface is further reduced, and the printed recorded image becomes a low-gloss recorded image and is not visually recognizable. .

Further, it has been attempted to provide an ink receiving layer on a highly smooth sheet-like support such as a plastic film or a laminated paper to obtain a gloss image as high as photographic printing paper. When an inorganic fine powder is mixed with the dispersible resin, an image having high gloss cannot be obtained, and the adhesion strength of the ink receiving layer to the support decreases. As a method of improving this point, a method of finishing the paper surface by processing with a super calender or a gloss calender is generally performed. However, such a method has a drawback that the ink receiving layer is compressed and densified, so that the ink absorbency is reduced.

As a recording paper for maintaining gloss, a water-soluble resin (for example, polyvinyl alcohol, polyvinylpyrrolidone, gelatin, carboxymethyl cellulose, etc.) capable of absorbing aqueous ink is used as a main component to improve water resistance. There has been proposed an ink jet recording paper in which a swellable ink receiving layer using a crosslinking agent (eg, glyoxal, a water-soluble epoxy compound, etc.) as an auxiliary agent is provided on a plastic film. However, although the ink jet recording paper containing such a water-soluble resin as a main component is excellent in terms of high gloss, in terms of ink absorption and water resistance, when the amount of the crosslinking agent is small,
If the water resistance is low and the amount of the cross-linking agent is increased in an attempt to improve the water resistance, the ink absorptivity greatly decreases, so that both the ink absorptivity and the water resistance cannot be satisfied.

[0007] In order to solve these problems, various proposals have hitherto been made in systems using inorganic fine particle fillers which can be expected to have high gloss. For example, Japanese Patent Application Laid-Open No. 2-2
JP-A-76670 and JP-A-3-281383 disclose an ink jet recording paper provided with an ink receiving layer having pores formed from pseudo-boehmite fine particles. However, although the present ink-receiving layer shows high ink absorbency, it has a drawback that production efficiency is poor because of low film-forming property in production, and further, in terms of cost,
There is a problem that it is difficult to reduce the cost because expensive pseudo-boehmite fine particles are used.

[0008]

SUMMARY OF THE INVENTION According to the present invention, an ink for ink-jet printing can be quickly absorbed, ink bleeding can be prevented, good water resistance can be obtained, and a high gloss image can be obtained. It is intended to provide an ink jet recording sheet.

[0009]

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that amorphous silica produced by the gel method has a pulverized average particle size of 100 to 350.
The inventors have found that the above problems can be solved by providing an ink receiving layer using a silica fine particle having a specific particle size of 150 m ² / g or more with a specific surface area of 150 nm ² / g or more (by the BET method), and the present invention has been provided. That is, the present invention is an ink jet recording sheet having an ink receiving layer provided on a thermoplastic resin film, wherein the ink receiving layer has an average particle diameter of 100 to 350 nm obtained by pulverizing amorphous silica produced by a gel method. , Specific surface area (by BET method) 15
The object of the present invention is to provide an ink jet recording sheet containing silica fine particles of 0 m ² / g or more and a binder resin, and having a P / B ratio (weight ratio of silica fine particles / binder resin) in the range of 3 to 5. is there.

The ink jet recording sheet of the present invention has a surface glossiness (JIS Z-8741; measured at 60 degrees) of 40.
% Is preferable. In addition, the thermoplastic resin film has glossiness (JIS Z-8741; measured at 60 degrees).
Is 70% or more and whiteness (JIS P-8123) is 80
%, And an opacity (JIS P-8138) of 85% or more is preferably a thermoplastic resin film.
In the present invention, the amorphous silica produced by the gel method,
Average particle size 2 in which primary particles having an average particle size of 1 to 10 nm are aggregated
〜１０10 μm, specific surface area (by BET method) 300 m ² /
g or more of amorphous silica, and it is particularly preferable that the surface is cationically treated.

In the present invention, the binder resin receiving the ink has a polymerization degree of 3,000 or more and a saponification degree of 80 to 100.
% Polyvinyl alcohol,
Further, as a crosslinking agent in the ink receiving layer, one selected from urea-formaldehyde resin, melamine-formaldehyde resin, and polyamide polyurea-formaldehyde resin.
It is preferable to contain 1 to 20% by weight of a kind or two or more kinds, and 1 to 20% by weight of an ink fixing agent. Further, in the present invention, it is preferable to provide a top coat layer on the ink receiving layer. Further, the top coat layer contains 70 to 95% by weight of a fine particle filler having an average particle diameter of 350 nm or less, and has a surface glossiness (JIS Z-8741). (Measured at 60 degrees) is preferably 50% or more, particularly preferably 1 to 20% by weight of the ink fixing agent in the top coat layer.

Further, the top coat layer of the present invention has a dot diameter ratio (D1 / D2) which is the ratio of the average ink dot diameter D1 of the top coat layer to the average ink dot diameter D2 of the ink receiving layer when printing with an ink jet printer. , 1.05
And an ink density ratio (M1 / M2), which is a ratio of the average ink density M1 of the top coat layer to the average ink density M2 of the ink receiving layer, is preferably 1.05 to 1.50. Preferably it is 50. Further, the thermoplastic resin film of the present invention is preferably a porous stretched resin film. In the present invention, “to” is a range including the numbers described before and after it as the minimum value and the maximum value. The average dot diameter is the average value of the dot diameters of 10 ink dots in a 3% yellow solid printing portion when a color chart is printed on the ink jet recording paper by an ink jet printer.
Further, the ink density is an average value of Macbeth densities of black, cyan, magenta, and yellow solid 100% printed portions in the color chart.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The ink jet recording paper of the present invention will be described in more detail. Support [Material] The support used in the present invention has a glossiness (JIS
Z-8741; measured at 60 degrees) is 70% or more, preferably 80% or more, and the whiteness (JIS P-8123) is 8
0% or more, preferably 90 to 100%, opacity (JI
(SP-8138) is 85% or more, preferably 90% or more. If the glossiness is less than 70%, the glossiness of the ink receiving layer provided thereon is also undesirably reduced. When the whiteness is less than 80%, not only the appearance of white paper before printing is reduced, but also the appearance of the ink-jet printed matter is unfavorably reduced. When the opacity is less than 85%, not only the appearance of blank paper before printing is reduced, but also the appearance of ink-jet printed matter is unfavorably reduced.

In the present invention, the type of the thermoplastic resin film used is not particularly limited. For example, ethylene resins such as high-density polyethylene and medium-density polyethylene, propylene resins, polyolefin resins such as polymethyl-1-pentene and ethylene-cyclic olefin copolymers; polyamides such as nylon-6 and nylon-6,6 Thermoplastic polyester resins such as polyethylene terephthalate and its copolymer, polybutylene terephthalate and its copolymer, and aliphatic polyester; polycarbonate, atactic polystyrene, syndiotactic polystyrene and the like can be used. Especially, it is preferable to use a nonpolar polyolefin resin.

Further, among the polyolefin resins, it is preferable to use a propylene resin from the viewpoint of heat resistance and cost. Examples of the propylene-based resin include an isotactic polymer or a syndiotactic polymer obtained by homopolymerizing propylene.
In addition, ethylene, 1-butene, 1-hexene, 1-heptene, 4-methyl-1-pentene and other α-olefins and propylene copolymerized, polypropylene having various stereoregularities as a main component. Copolymers can also be used. The copolymer may be a binary system, a ternary system or more, or a random copolymer or a block copolymer. The propylene-based resin is preferably used by blending a resin having a lower melting point than that of the propylene homopolymer in an amount of 2 to 25% by weight. High-density or low-density polyethylene can be exemplified as such a resin having a low melting point.

As the thermoplastic resin for the support, one of the above thermoplastic resins may be selected and used alone, or two or more may be selected and used in combination. In the thermoplastic resin to be used as the support, inorganic fine powder, organic filler, stabilizer, light stabilizer, dispersant,
A lubricant or the like can be added. When adding an inorganic fine powder, one having a particle size of usually 0.01 to 15 μm, preferably 0.01 to 5 μm is used. Specifically, heavy calcium carbonate, light calcium carbonate, calcined clay,
Amorphous silica, diatomaceous earth, talc, titanium oxide, barium sulfate, alumina and the like can be used.

When an organic filler is added, it is preferable to select a resin different from the thermoplastic resin as the main component. For example, when the thermoplastic resin film is a polyolefin resin film, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, nylon-6, nylon-
6,6, a polymer such as a cyclic olefin, polystyrene, or polymethacrylate having a melting point (for example, 170 to 300 ° C.) or a glass transition temperature (for example, 170 to 280 ° C.) higher than the melting point of the polyolefin resin. Can be used.

When a stabilizer is added, usually 0.001
It is added within the range of １1% by weight. Specifically, sterically hindered phenol-based, phosphorus-based, amine-based stabilizers and the like can be used. When a light stabilizer is added, it is usually 0.1.
It is added in the range of 001 to 1% by weight. Specifically, sterically hindered amine-based, benzotriazole-based, benzophenone-based light stabilizers and the like can be used. The dispersant and the lubricant are used, for example, for the purpose of dispersing the inorganic fine powder. The amount used is usually in the range of 0.01 to 4% by weight.
Specifically, silane coupling agents, higher fatty acids such as oleic acid and stearic acid, metal soaps, polyacrylic acid,
Polymethacrylic acid and salts thereof can be used.

[Molding] The method of forming the thermoplastic resin film is not particularly limited, and it can be appropriately selected from known methods. For example, cast molding for extruding a molten resin into a sheet using a single-layer or multilayer T-die or I-die connected to a screw type extruder, calender molding, rolling molding, inflation molding, thermoplastic resin and organic solvent or Casting or calendering the mixture with oil and then removing the solvent or oil, molding using a thermoplastic resin solution and then removing the solvent can be used.

[Stretching] The thermoplastic resin film used for the support may be a stretched one. Stretching can be performed by any of various methods commonly used. The stretching temperature is suitable for a thermoplastic resin having a glass transition point temperature or higher of a thermoplastic resin to be used in the case of an amorphous resin, or a glass transition point temperature or higher of an amorphous portion to a melting point of a crystal portion or lower in the case of a crystalline resin. It can be performed within any known temperature range. Specifically, the stretching temperature is preferably 2 to 60 ° C. lower than the melting point of the thermoplastic resin used. When the resin is a propylene homopolymer (melting point: 155 to 167 ° C.), the stretching temperature is 152 to 164 ° C. Melting point 121
To 134 ° C.) and 110 to 120 ° C. for polyethylene terephthalate (melting point: 246 to 252 ° C.).
The temperature is preferably set to 4 to 115 ° C. The stretching speed is preferably set to 20 to 350 m / min.

As the stretching method, there can be used longitudinal stretching utilizing a difference in peripheral speed of the roll group, transverse stretching using a tenter oven, rolling, simultaneous biaxial stretching using a combination of a tenter oven and a linear motor, and the like. The stretching ratio is not particularly limited, and is appropriately determined in consideration of the characteristics of the thermoplastic resin used. For example, when a propylene homopolymer or a copolymer thereof is used as the thermoplastic resin, it is about 1.2 to 12 times, preferably 2 to 10 times when stretched in one direction, and 2 to 10 times when stretched biaxially. The area magnification is 1.5 to 60 times, preferably 10 to 50 times. When using other thermoplastic resins, when stretched in one direction is 1.2 to 10 times, preferably 2 to 5 times,
In the case of biaxial stretching, the area ratio is 1.5 to 20 times, preferably 4 to 12 times.

When a thermoplastic resin containing an inorganic fine powder or an organic filler is stretched, a stretched porous resin film having fine pores therein can be obtained. At this time,
The porosity calculated by the following equation is preferably in the range of 5 to 60%.

(Equation 1) The physical properties of the stretched thermoplastic resin film preferably have a density of 0.650 to 1.20 g / cm ³ , an opacity of 75% or more, and a Beck smoothness of 50 to 25,000 seconds.

[Layer Structure] The support of the ink-jet paper of the present invention may be composed of a single layer or a multilayer. For example, a single-layer support made of a polyolefin-based resin film contains 40 to 99.5% by weight of a polyolefin-based resin and inorganic fine powder 6
Prepared by stretching a resin film comprising a resin composition containing 0 to 0.5% by weight in a uniaxial or biaxial direction at a temperature lower than the melting point of the polyolefin resin (preferably at a temperature lower by 3 to 60 ° C). can do. Also,
The support having a multilayer structure is a polyolefin resin 40
A resin film comprising a resin composition containing 100 to 100% by weight and 60 to 0% by weight (preferably 50 to 0% by weight) of an inorganic fine powder is heated to a temperature lower than the melting point of the polyolefin resin (preferably 3 to 60 ° C lower). Temperature)) and stretched in the machine direction at least on one side of the stretched film.
It can be prepared by laminating a resin film made of a resin composition containing 5 to 0% by weight. The surface layer laminated on the stretched film may be an unstretched resin layer.

Particularly preferred supports are calcined clay,
By uniaxially stretching a polyolefin resin film containing 8 to 65% by weight of an inorganic fine powder such as heavy calcium carbonate, light calcium carbonate, titanium oxide, talc, etc. A crack is formed to form a translucent or opaque film, and the surface has an inorganic fine powder content of 8% by weight.
Hereinafter, a film obtained by laminating a resin composition, preferably 5% by weight or less, may be mentioned. In particular,
JP-B 1-60411 and JP-A-61-374.
No. 8, such as synthetic paper having a surface layer of a polyolefin resin film substantially free of inorganic fine powder.

The thickness of the support of the present invention is usually from 20 to 35.
It is set in the range of 0 μm, preferably in the range of 35 to 300 μm. Preferred as such a white propylene-based resin film is a microporous synthetic paper made of a stretched propylene-based resin film having fine voids inside the film, and having a porosity calculated by the formula (1). 1
0-60%, preferably 15-45%, wall thickness 30-3
A microporous synthetic paper of 00 μm, preferably 50 to 150 μm is mentioned.

Ink Receiving Layer The ink receiving layer of the present invention comprises silica fine particles having an average particle diameter of 100 to 350 nm and a specific surface area (by BET method) of 150 m ² / g or more obtained by pulverizing amorphous silica produced by a gel method, and a binder. Containing resin and P / B
The ink receiving layer has a ratio (weight ratio of silica fine particles / binder) of 3 to 5. The ink receiving layer has a surface glossiness (JIS Z-
8741; 60 ° measurement) is preferably 40% or more.

[Silica Fine Particles] In the present invention, amorphous silica produced by the gel method is pulverized to an average particle diameter of 100 to 350.
By using silica fine particles having a specific surface area of 150 m ² / g or more and a specific surface area (by the BET method) of 150 m ² / g or more, an ink receiving layer having high gloss and high ink absorption can be obtained. When silica fine particles having an average particle diameter of less than 100 nm are used, the glossiness of the ink receiving layer increases, but the ink absorbency decreases, which is not preferable. It is not preferable to use silica fine particles having an average particle diameter of more than 350 nm, because the glossiness of the ink receiving layer is greatly reduced. The specific surface area is 150m
Use of silica fine particles of less than ² / g is not preferred because the ink absorption of the ink receiving layer is reduced with a decrease in specific surface area.

Hereinafter, the amorphous silica produced by the gel method (hereinafter abbreviated as “gel method silica”) used in the present invention will be described in detail. Amorphous silica can be roughly classified into dry silica and wet silica according to its production method, and wet silica is produced by a gel method (hereinafter abbreviated as “gel method silica”) and a sedimentation method. Silica (hereinafter abbreviated as “precipitated silica”). Dry process silica is spherical anhydrous silica having an average primary particle size of 5 to 50 nm produced by high-temperature gas-phase hydrolysis of silicon halide. Dry silica has a small apparent specific gravity and a high surface area, but it is not preferable because the spherical particles are easily aggregated in a net-like manner, so that it is difficult to disperse in water and the stability of the dispersion over time is low. In contrast, wet-process silica is hydrous silica having an average particle size of 2 to 200 μm produced by polymerizing and coagulating and sedimenting a silica sol formed from sodium silicate. Depending on its primary particle size, gel-processed silica and precipitated silica are used. Is subdivided into

The gel silica has a primary particle diameter of 1 to 10 nm.
Silica, precipitated silica has a primary particle diameter of 10 to 50 nm
Is classified as silica. When gel silica and precipitated silica are compared, gel silica has strong cohesive force of primary particles and high surface area, whereas precipitated silica has low cohesive force of primary particles and low specific surface area. . When the precipitated silica is pulverized to an average particle diameter of 100 to 300 nm and used as fine silica particles in the ink receiving layer, only a low-gloss ink receiving layer is obtained, probably because of the large primary particle diameter. At the same time, because of the low specific surface area of the obtained silica fine particles, an ink receiving layer having low ink absorbability is obtained.

On the other hand, the gel silica was used in an average particle size of 1
When the particles are pulverized to a particle size of 00 to 300 nm and used as the silica fine particles in the ink receiving layer, the primary particle diameter is 1 to 10 n.
m, it is possible to produce an ink-receiving layer with high gloss and high transparency when used in the ink-receiving layer. In addition, the produced silica fine particles also have a high specific surface area, so that inks with high ink absorption A receiving layer can be manufactured. Further, the gel silica used in the present invention preferably has an average particle diameter of 2 to 10 μm in order to perform highly efficient pulverization, and has a specific surface area (BE) in order to produce fine silica having a high specific surface area.
It is preferably at least 300 m ² / g (by T method).

Further, as the gel method silica used in the present invention, it is preferable to use silica whose surface is cationically treated in order to improve the fixing property of the ink for ink jet. The cationic treatment is a treatment in which the silica surface is coated with a cationic agent at the time of crushing or producing silica. Examples of the cationic agent include inorganic metal salts, cationic coupling agents, and cationic polymers. Is mentioned. Specific examples of the inorganic metal salt include inorganic metal oxide hydrates such as aluminum oxide hydrate, zirconium oxide hydrate, and tin oxide hydrate, and aluminum hydroxide, aluminum sulfate, aluminum chloride, and aluminum acetate. And water-soluble inorganic metal salts such as aluminum nitrate, zirconium sulfate, zirconium chloride and tin chloride.

Specific examples of the cationic coupling agent include a cationic silane coupling agent such as an amino group-containing silane coupling agent and a quaternary ammonium group-containing silane coupling agent; an amino group-containing zirconium coupling agent; A cationic zirconium coupling agent such as a quaternary ammonium group-containing zirconium coupling agent, and an amino group-containing titanium coupling agent;
Examples include cationic titanium coupling agents such as quaternary ammonium group-containing titanium coupling agents, and cationic glycidyl coupling agents such as amino group-containing glycidyl ethers and quaternary ammonium group-containing glycidyl ethers.

Specific examples of the cationic polymer include polyalkylene polyamines such as polyethyleneimine and polypropylene polyamine, or derivatives thereof, acrylic polymers containing amino groups and quaternary ammonium groups, and polyvinyl alcohols containing amino groups and quaternary ammonium salts. And the like. The method of pulverizing silica used in the present invention is not particularly limited, but a mechanical pulverization method using a pulverizer is preferable in view of uniformity of quality and pulverization at low cost. Specific examples of the pulverizer include an ultrasonic pulverizer, a jet mill, a sand grinder, a roller mill, a high-speed rotation mill, and the like. The average particle size in the present invention is obtained by observing the cross section or surface of a silica particle or an ink receiving layer with a scanning electron microscope and measuring and averaging the particle sizes of 100 arbitrary particles. is there.

[Binder Resin] In the ink receiving layer of the present invention, examples of the binder resin used in combination with the above silica fine particles include polyvinyl alcohol and derivatives thereof, polyvinyl pyrrolidone, polyacrylamide, hydroxyethyl cellulose, casein, starch and the like. Resins, urethane resins, ester resins, epoxy resins, ethylene resins, ethylene-vinyl acetate copolymer resins, vinyl acetate resins, vinyl chloride resins, vinyl chloride-vinyl acetate copolymer resins, chlorides Vinylidene resin, vinyl chloride-vinylidene chloride copolymer resin, acrylic acid resin, methacrylic resin, polybutyral resin, silicone resin, nitrocellulose resin,
A water-insoluble resin resin such as a styrene-acrylic copolymer resin, a styrene-butadiene-based copolymer resin, and an acrylonitrile-butadiene-based copolymer resin can be used. The water-soluble resin is used as an aqueous solution, and the water-insoluble resin is used as a solution, emulsion, or latex.

Among the above binder resins, polyvinyl alcohol is preferred from the viewpoint of miscibility with silica fine particles and ink absorption. Particularly, from the viewpoint of coating film strength, the polymerization degree is 3
Polyvinyl alcohol having a saponification degree of 80 to 95% or more is preferable. In the present invention, the P / B ratio (weight ratio between the silica fine particles and the binder resin) is preferably 3 to 5. When the P / B ratio is less than 3, the amount of voids in the silica fine particles decreases and ink absorbency decreases. When the P / B ratio exceeds 5, the coating film strength sharply increases due to a decrease in the binder function. descend. In the present invention, in order to improve the water resistance of the binder resin, it is preferable to add one or more selected from urea-formaldehyde resin, melamine-formaldehyde resin, and polyamide polyurea-formaldehyde resin. Commonly used crosslinking agents other than the above crosslinking agents, glyoxal, epoxy-based crosslinking agents,
Boric acid and the like, but urea-formaldehyde resin, melamine-
It is preferable to use a formaldehyde resin or a polyamide polyurea-formaldehyde resin.

The amount of the crosslinking agent to be added is from 1 to 2 of the ink receiving layer.
It is preferable to use it in the range of 0% by weight. In the present invention, it is preferable to add an ink fixing agent to the ink receiving layer in order to improve the ink fixing property. As an ink fixing agent,
Examples thereof include an inorganic metal salt, a cationic coupling agent, and a cationic polymer. Specific examples of the inorganic metal salt include:
Inorganic metal oxide hydrates such as aluminum oxide hydrate, zirconium oxide hydrate, tin oxide hydrate, aluminum hydroxide, aluminum sulfate, aluminum chloride,
Water-soluble inorganic metal salts such as aluminum acetate, aluminum nitrate, zirconium sulfate, zirconium chloride, and tin chloride are exemplified.

Specific examples of the cationic coupling agent include a cationic silane coupling agent such as an amino group-containing silane coupling agent and a quaternary ammonium group-containing silane coupling agent; an amino group-containing zirconium coupling agent; Cationic zirconium coupling agents such as zirconium coupling agents such as quaternary ammonium group-containing zirconium coupling agents, and cationic titanium coupling agents such as amino group-containing titanium coupling agents and quaternary ammonium group-containing titanium coupling agents; And amino group-containing glycidyl ether, 4
And a cationic glycidyl coupling agent such as a glycidyl ether containing a quaternary ammonium group.

As a specific example of the cationic polymer,
Polyethylene, such as ethyleneimine and polypropylene polyamine
Alkylene polyamines or their derivatives, amino groups
And quaternary ammonium group-containing acrylic polymer, amino
Group or quaternary ammonium salt-containing polyvinyl alcohol
No. The amount of the ink fixing agent added is 1 in the ink receiving layer.
Preferably, it is used in the range of -20% by weight. The present invention
The ink-receiving layer is generally used for coated paper as needed.
Used dispersants, thickeners, defoamers, preservatives, UV absorption
Contains various auxiliaries such as chemicals, antioxidants and surfactants
You can also. The coating amount of the ink receiving layer of the present invention is 1
5 to 40 g / m^TwoIt is preferred that 15 coats
g / m^TwoIf it is less than 4, the ink absorption amount is insufficient, and 4
0 g / m ^TwoIf it exceeds, the ink absorption amount is satisfactory
However, the surface strength of the ink receiving layer decreases.

Top Coat Layer In the present invention, it is preferable to provide a top coat layer on the ink receiving layer for the purpose of improving glossiness, improving ink absorption speed, and improving ink color density. The top coat layer of the present invention preferably contains 70 to 95% by weight of an inorganic filler having an average particle diameter of 350 nm or less, and particularly preferably contains an inorganic filler having an average particle diameter of 300 nm or less in an amount of 80 to 90%.
%. Use of an inorganic filler having an average particle diameter of more than 350 nm is not preferred because the glossiness of the top coat layer is reduced. When the content of the inorganic filler is less than 70% by weight, the ink permeability is greatly reduced because the filler void is reduced. If it exceeds 95% by weight, the surface strength of the top coat layer is greatly reduced. Further, the surface glossiness (J
IS Z-8741; measured at 60 degrees) is preferably 50% or more.

The coating amount of the top coat layer is 0.1 to
5.0 (g / m ² ), preferably 0.5 to 3.0 (g / m ² )
m ² ). Coating amount is 0.1 (g / m
If it is less than ² ), the effect of the top coat layer will not be sufficiently exhibited, and if it exceeds 5.0 (g / m ² ), the effect will be saturated. The inorganic filler used in the present invention includes a spherical inorganic filler and a non-spherical inorganic filler. Specific examples of the spherical inorganic filler include spherical colloidal silica, spherical colloidal carbon, spherical aluminum oxide, and spherical titanium dioxide. Specific examples of the non-spherical inorganic filler include silica fine particles obtained by pulverizing the gel silica used in the ink receiving layer in the present invention, pearl necklace-shaped colloidal silica, fibrous aluminum oxide, and plate-like aluminum oxide. The top coat layer contains 5 to 30% by weight of a binder resin as an adhesive.

Specific examples of the binder resin include, for example, water-soluble resins such as polyvinyl alcohol and derivatives thereof, polyvinylpyrrolidone, polyacrylamide, hydroxyethylcellulose, casein, starch, urethane resins, ester resins, epoxy resins, and the like. Ethylene resin, ethylene-vinyl acetate copolymer resin, vinyl acetate resin, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinylidene chloride resin, vinyl chloride-vinylidene chloride copolymer resin, acrylic acid Resin such as methacrylic acid resin, polybutyral resin, silicone resin, nitrocellulose resin, styrene-acryl copolymer resin, styrene-butadiene copolymer resin, acrylonitrile-butadiene copolymer resin, etc. Uses water-soluble resin Rukoto can. The water-soluble resin is an aqueous solution, the water-insoluble resin is a solution, an emulsion,
Or used as latex.

Among the above binder resins, polyvinyl alcohol, urethane resin, acrylic resin, and styrene-butadiene resin are used in view of the miscibility with the inorganic filler and the adhesion strength with the thermoplastic resin film and the ink receiving layer. Polymer resins are preferred. The top coat layer of the present invention preferably contains a cationic ink fixing agent in an amount of 1 to 20% by weight for the purpose of improving the ink fixing property. As the ink fixing agent, the same type of fixing agent as the ink fixing agent used for the ink receiving layer can be used. In the top coat layer of the present invention, if necessary, various aids such as dispersants, thickeners, defoamers, preservatives, ultraviolet absorbers, antioxidants and surfactants generally used in coated papers are used. An agent can also be included.

In the present invention, by providing the top coat layer on the ink receiving layer, the ink penetration speed is improved, and at the same time, the dot diameter is appropriately enlarged, and additionally the ink density is improved. In the present invention, the dot diameter ratio (D1 / D2) of the average ink dot diameter D1 of the top coat layer to the average ink dot diameter D2 of the ink receiving layer is preferably in the range of 1.05 to 1.50. The dot diameter ratio (D1 / D2) is 1.
If it is less than 0.05, the effect of improving the ink penetration speed by the top coat layer is insufficient, and the dot diameter ratio (D1 / D1 / D1) is not sufficient.
If D2) is more than 1.50, ink bleeding occurs, and the image quality deteriorates. Further, in the present invention, the ink concentration ratio (M1 / M2) of the average ink concentration M1 of the top coat layer to the average ink concentration M2 of the ink receiving layer is 1.05 to 1.05.
It is preferably 1.50. Ink density ratio (M1 /
When M2) is less than 1.05, the effect of expanding the dot diameter by the top coat layer is insufficient, and the density ratio (D1
When / D2) is more than 1.50, ink bleeding occurs and the image quality deteriorates.

Coating Method The method for applying the above-described ink receiving layer and top coat layer to a thermoplastic resin film can be appropriately selected from known methods. Examples of the coating method include a blade coating method, a rod bar coating method, a roll coating method, an air knife coating method, a spray coating method, a gravure coating method, a curtain coating method, a die coating method, and a comma coating method.

[0045]

EXAMPLES The present invention will be described more specifically with reference to Production Examples, Examples, Comparative Examples and Test Examples. The materials, amounts used, ratios, operations, and the like shown below can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples. The percentages described below are based on weight unless otherwise specified. The materials used are summarized in Table 1.

Production Example of Support [Production Example 1] (1) Melt flow rate (MFR) 1.2 g / 10 min. 80% by weight of polypropylene (melting point: 164 ° C.), 3.5% by weight of high-density polyethylene and average particle size 16% by weight of 1.5 μm diameter calcium carbonate, 0.5% by weight of titanium white
Was kneaded by an extruder set at 270 ° C., extruded into a sheet, and cooled by a cooling device to obtain a non-stretched sheet. Then, this sheet is
After heating again to a temperature of 40 ° C., it was stretched 5 times in the machine direction. (2) Polypropylene 55 having an MFR of 4.0 g / 10 minutes
Weight% and calcium carbonate having an average particle size of 1.5 μm.
The composition (B) in which 5% by weight and 0.5% by weight of titanium white were mixed was kneaded with another extruder, extruded into a strand shape, and cut into pellets.

Next, the composition (B) and the polypropylene (C) having an MFR of 4.0 were melt-kneaded in separate extruders and then laminated in a die in two layers. A laminated film having a five-layer structure was obtained by laminating on both sides of the stretched film composed of the composition (A) of the above (1) so that the polypropylene (C) was on the outside. Next, after cooling the laminated film having the five-layer structure to 60 ° C., it is heated again to a temperature of about 160 ° C., stretched 7.5 times in the transverse direction using a tenter, and annealed at a temperature of 165 ° C. After cooling to a temperature of 60 ° C. and corona discharge treatment, the ears were slit and the wall thickness was 120 μm (C / B /
A / B / C = 10 μm / 10 μm / 80 μm / 10 μm
/ 10 μm) having a five-layer structure. This synthetic paper was used as a support a.

[Production Example 2] Synthetic paper "Yupo FPG-130" made of a propylene-based resin stretched laminated film having a thickness of 130 μm and a surface gloss of 16.4% (trade name, manufactured by Oji Oil Chemicals, Ltd.) Was used as a support b.

[0049]

[Table 1]

(Examples 1 to 6 and Comparative Examples 1 to 5) Table 1
A sheet for ink jet recording was manufactured according to the following procedure using a predetermined amount of the material described in (1). That is, silica fine particles, a binder resin, a crosslinking agent, an ink fixing agent, and water were mixed to prepare a coating liquid for forming an ink receiving layer. This coating solution was applied on the support 1 with a Mayer bar so that the coating amount after drying was 20 g / m ² ,
The ink was dried and solidified in an oven at a temperature of 5 ° C. for 5 minutes to form a receptor layer to obtain an ink jet recording sheet.

(Examples 7 to 12 and Comparative Examples 6 and 7) Ink-jet recording sheets were produced according to the following procedures using the materials shown in Table 1 in predetermined amounts. That is, an inorganic filler, a binder resin and water were mixed to prepare a coating liquid for forming a top coat layer. This coating liquid was applied onto the ink jet recording paper obtained in Example 6 with a Mayer bar so that the coating amount after drying was 1.0 g / m ^2, and dried in an oven at 110 ° C. for 1 minute. By solidifying to form a top coat layer, an ink jet recording paper was obtained.

(Evaluation) The ink jet recording paper obtained above was evaluated by the following test methods. Table 2 shows the results. (1) Surface glossiness Measured with a gloss meter (UGV-5D, manufactured by Suga Test Instruments Co., Ltd.) in accordance with JIS Z-8741 (specular glossiness at an incident angle of 60 degrees and a light-receiving angle of 60 degrees) and measured five times. Were averaged. (2) Surface Crack The presence or absence of cracks in the ink receiving layer was visually judged according to the following criteria. ○ No cracking △ Cracking partially occurred × Cracking all over

(3) Ink Absorption Printing was performed under the following conditions using an ink jet printer “PM-770C” (trade name, manufactured by Epson Corporation). Sample: Japanese Standards Association SCID color chart sample "S7" A4 (6.6 x 14.3 cm) Print settings: Recommended settings clean, no color correction by driver Usage environment: Windows 95 Pentium II
300MHz, RAM128MB Parallel I / F Software used: Adobe Photoshop 4.0
J After completion of printing, the time when the ink completely disappeared from the printed portion was defined as the drying time. The drying time was evaluated in the following four grades. ：: Drying time 0 minutes (the ink is completely absorbed at the end of printing) ：: Drying time 0 to 1 minute △: Drying time 1 to 3 minutes ×: Drying time 3 minutes or more

(4) Ink bleeding property The presence or absence of ink bleeding in the print sample used in the above-described ink absorption test was visually determined according to the following criteria. ：: No bleeding observed Δ: Bleeding observed only in heavy color portion ×: Bleeding observed in heavy color portion and single color portion (5) Water resistance A sufficient print sample printed under the same conditions as in the above ink absorption test After being immersed in an amount of tap water (water temperature 25 ° C.) for 4 hours, the paper surface was air-dried and the degree of ink remaining was visually determined. Ink residual ratio: 100 to 80% ○ 80 to 50% △ 50 to 0% ×

(6) Ink dot diameter The ink dots were enlarged and measured with an optical microscope for a solid 3% solid printed portion of a print sample printed under the same conditions as in the above-described ink absorption test. The average value measured at 10 points was taken as the ink dot diameter. (7) Ink Concentration In each of the print samples printed under the same conditions as those in the above-described ink absorption test, 10 samples of cyan, magenta, yellow, and black were printed.
The Macbeth density was measured for the 0% solid printing portion using a Macbeth densitometer (trade name: RD-918, manufactured by Sakata Engineering Co., Ltd.), and the average value of the Macbeth densities of cyan, magenta, yellow, and black was defined as the ink density.

[0056]

[Table 2]

From the results shown in Table 2, it can be seen that the ink jet recording paper provided with the ink receiving layer of the present invention (Examples 1 to 6) is excellent in surface gloss, ink absorbency and water resistance. In contrast, P which deviates from the definition of the present invention
Inkjet recording paper using a receptor layer at a / B ratio (Comparative Examples 1 and 2) and inkjet recording paper using a receptor layer containing polyvinyl alcohol having a low degree of polymerization (Comparative Example 3), and were manufactured by a sedimentation method. Ink jet recording paper using a receiving layer containing silica (Comparative Example 4) and ink jet recording paper using a support having a low surface gloss (Comparative Example 5) are both inferior in characteristics to the present invention. .

Further, from the results in Table 2, it can be seen that the ink jet recording paper provided with the top coat layer of the present invention (Examples 7 to 1)
In 2), the ink penetration speed is improved, and at the same time, the ink dot diameter is appropriately enlarged, and the ink density is improved. On the other hand, ink jet recording paper using a top coat layer having a filler content deviating from the definition of the present invention (Comparative Examples 6 and 7)
Are inferior in characteristics to the present invention.

[0059]

As described above, the ink jet recording paper of the present invention can rapidly absorb ink, does not cause bleeding, has good water resistance, has a high ink density, and can provide a high gloss image.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Hiroo Hayashi 23rd Towada, Kamisu-cho, Kashima-gun, Ibaraki Pref. BA46 BA48

Claims (14)

[Claims] 1. An ink receiving layer on a thermoplastic resin film
An ink jet recording sheet provided with
Layer has crushed amorphous silica produced by gel method
Average particle size 100 to 350 nm, specific surface area (by BET method)
150m ^Two/ G or more of silica fine particles and vine
P / B ratio (silica fine particles)
/ Weight ratio of binder resin) is in the range of 3 to 5.
A sheet for inkjet recording characterized by the above. 2. The ink jet recording sheet has a surface glossiness (JIS Z-8741; measured at 60 °) of 40%.
2. The ink jet recording sheet according to claim 1, wherein: 3. The method according to claim 1, wherein the thermoplastic resin film has a glossiness (J
IS Z-8741; measured at 60 degrees) is a thermoplastic resin film having 70% or more, whiteness (JIS P-8123) of 80% or more, and opacity (JIS P-8138) of 85% or more. Claim 1 or 2
The sheet for inkjet recording according to the above. 4. The amorphous silica produced by the gel method has an average particle diameter of 2 to 10 μm in which primary particles have an average particle diameter of 1 to 10 nm.
10 μm, specific surface area (by BET method) 300 m ² / g
The inkjet recording sheet according to any one of claims 1 to 3, which is the above-mentioned amorphous silica. 5. The ink jet recording sheet according to claim 1, wherein the amorphous silica produced by the gel method is an amorphous silica whose surface is treated with a cation. 6. The ink jet recording sheet according to claim 1, wherein the binder resin is polyvinyl alcohol having a degree of polymerization of 3,000 or more and a degree of saponification of 80 to 100%. 7. The ink receiving layer according to claim 1, wherein one or more selected from urea-formaldehyde resin, melamine-formaldehyde resin, and polyamide polyurea-formaldehyde resin are contained in an amount of 1 to 20% by weight as a crosslinking agent. The inkjet recording sheet according to any one of claims 1 to 6, wherein: 8. An ink fixing agent containing 1 ink fixing agent in the ink receiving layer.
The ink-jet recording sheet according to any one of claims 1 to 7, wherein the content of the ink-jet recording sheet is from 20 to 20% by weight. 9. The ink jet recording sheet according to claim 1, wherein a top coat layer is further provided on the ink receiving layer. 10. The method according to claim 1, wherein the top coat layer has an average particle diameter of 350.
containing 70 to 95% by weight of a fine particle filler having a particle size of
And surface glossiness (JIS Z-8741; measured at 60 degrees)
The sheet for inkjet recording according to claim 9, wherein the ratio is 50% or more. 11. The ink composition according to claim 9, wherein the top coat layer contains 1 to 20% by weight of an ink fixing agent.
Or the inkjet recording sheet according to 10. 12. A dot diameter ratio (D1 / D2), which is a ratio of an average ink dot diameter D1 of the top coat layer to an average ink dot diameter D2 of the ink receiving layer, is 1.05 to 1.5.
The inkjet recording sheet according to any one of claims 9 to 11, wherein the value is in the range of 0. 13. An average ink density M of the top coat layer.
13. The ink jet according to claim 9, wherein an ink density ratio (M1 / M2), which is a ratio of 1 to an average ink density M2 of the ink receiving layer, is 1.05 to 1.50. Recording sheet. 14. The thermoplastic resin film is a stretched porous resin film.
The inkjet recording sheet according to any one of the above.