JP2001232935A - Manufacturing method for water-base ink jet recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a water-base ink jet recording sheet, which is excellent in the absorbability and color developability of a water-base ink jet ink and with which a clear, highly dense and, at the same time, precise and stainless image can be produced by a method wherein a smooth surface layer made of fine hydrophilic inorganic particles is produced on an ink accepting layer. SOLUTION: In order to manufacture the water-base ink jet recording sheet, under the state that a base material is run in a predetermined direction, the base material is dry-coated with powdered paint Next, the powdered paint is day-coated with fine hydrophilic inorganic particles. Then, the resultant base material is led to a first heat fixing device consisting of a fixing roller 17 having a predetermined surface temperature and a pressurizing roller 18 so as to be thermally pressurized between the rollers in order to produce the ink accepting layer made of the powdered paint on the base material. At the same time, at the fixing of the surface layer made of the fine hydrophilic inorganic particles on the ink accepting layer, the resin comprising the powdered paint has a melt starting temperature of 70 deg.C or higher and a melt viscosity at 100 deg.C of 20,000 to 1,000,000 poises.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a water-based ink jet recording sheet, and more particularly, to a water-based ink jet ink having excellent absorption and coloring properties, not only being sharp and high in density, but also accurate and free from distortion. The present invention relates to a method for producing an aqueous inkjet recording sheet capable of forming an image.

[0002]

2. Description of the Related Art Conventionally, various recording methods have been known. In recent years, aqueous ink-jet recording methods in which aqueous ink is ejected directly from nozzles onto recording paper and adhered thereto for recording have been widely used. Has reached.

Conventionally, this aqueous ink jet recording sheet is prepared by wet-coating a solution containing a water-soluble or water-swellable resin, a pigment and other additives on a base sheet, removing the solvent, and drying. Then, a layer composed of the resin layer in which the pigment was dispersed was formed as an ink receiving layer, and the pigment was allowed to adsorb the colorant in the ink, and the resin was allowed to absorb the moisture in the ink, thereby receiving the ink. An image is formed on the layer. Therefore, in such an ink jet recording sheet, since the surface of the ink receiving layer is generally covered with a continuous resin layer, the ink absorbing property of the ink jet ink is low, and the ink drying property is poor. However, there are also problems such as being limited to those having high water absorption. Further, according to the receiving layer as described above, the coloring property of the ink is not sufficient.

Further, from the viewpoint of the production, such a conventional ink jet recording sheet is formed by wet coating a coating liquid containing a resin, a pigment and other additives, and drying the coating liquid to form an ink receiving layer. Therefore, when removing the solvent, not only environmental considerations are required, but also the manufacturing cost of the recording sheet has to be increased.

Therefore, recently, for example, Japanese Unexamined Patent Publication No.
As described in Japanese Patent Application Publication No. 0-203031, a powder coating is dry-coated on an appropriate substrate such as plain paper by, for example, an electrostatic spray method, and a fixing roller and a pressure roller (backup roller) are used. A method of forming a resin layer made of a powder coating material as an ink receiving layer on a base material has been proposed.

The inventors of the present invention have further conducted intensive studies on the production of an aqueous ink jet recording sheet using such a powder coating, and as a result, it has been found that hydrophilic inorganic fine particles are formed on an ink receiving layer made of the powder coating. It has been found that by forming the surface layer, it is possible to obtain a water-based inkjet recording sheet which is more excellent in the absorbability and color-forming properties of the water-based inkjet ink and forms a clear and high-density image.

However, in the production of such an aqueous ink jet recording sheet, depending on the resin constituting the powder coating material, the present inventors dry-coat hydrophilic fine particles on the ink receiving layer, and use a heat fixing device. And pressurize and heat,
When fixing the hydrophilic inorganic fine particles on the ink receiving layer, just before the heat fixing device, the powder coating does not melt to the extent that the inorganic fine particles thereon can be received and fixed. There is a case where a so-called raised bank is formed by sliding on the body paint. When such a bank is formed, the inorganic fine particles, after passing through the heat fixing device, form a pattern, particularly a streak pattern, on the surface of the ink receiving layer made of the powder coating material, the surface having irregularities. When ink jet recording is performed on such an aqueous ink jet recording sheet, an image is distorted and an accurate image cannot be obtained.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems in the dry production of an aqueous ink jet recording sheet using a powder coating. It is possible to form a smooth surface layer composed of inorganic fine particles of the present invention, and thus to form not only a clear and high-density image but also an accurate and distortion-free image, which is excellent in the absorptivity and coloring of an aqueous inkjet ink. It is an object of the present invention to provide a method for producing an aqueous ink jet recording sheet that can be used.

[0009]

According to the method for producing an aqueous ink jet recording sheet of the present invention, a powder coating is dry-coated on a substrate while running the substrate in a predetermined direction. After dry coating with hydrophilic inorganic fine particles,
It is led to a first heat fixing device including a fixing roller having a predetermined surface temperature and a pressure roller, and heated under pressure between the rolls to form an ink receiving layer made of the powder coating on a substrate. In addition, in the method for producing an aqueous inkjet recording sheet in which the surface layer comprising the hydrophilic inorganic fine particles is fixed on the ink receiving layer, the resin constituting the powder coating has a melting start temperature of 70 ° C. or more. In addition, it has a melt viscosity in the range of 20,000 to 1,000,000 poise at 100 ° C.

Preferably, while the base material is traveling in a predetermined direction, the resin composition particles having an average particle size of 1 to 30 μm and an average particle size of 1 nm covering the surface of the resin composition particles are coated on the base material. Dry coating of a powder coating comprising from 1 to 1 μm of hydrophilic first inorganic fine particles, and then dry-coating of hydrophilic second inorganic fine particles thereon, having a predetermined surface temperature It is led to a heat fixing device comprising a fixing roller and a pressure roller, and is heated under pressure between the rolls to form an ink receiving layer made of the powder coating on a base material, and on the ink receiving layer. In the method for producing an aqueous inkjet recording sheet for fixing a surface layer composed of hydrophilic inorganic fine particles, the resin constituting the powder coating has a melting start temperature of 70 ° C. or more,
It has a melt viscosity in the range of 0000 to 1,000,000 poise.

Another method of manufacturing an aqueous ink jet recording sheet according to the present invention is to dry-coat a powder coating on a substrate while running the substrate in a predetermined direction, and to fix the substrate to a predetermined surface temperature. The first consisting of a roller and a pressure roller
And heated under pressure between the rolls to form an ink receiving layer composed of the powder coating on a substrate, and then dry-coated inorganic fine inorganic particles on the ink receiving layer. Coating, guiding to a second heat fixing device, pressurizing and heating between rollers, fixing the hydrophilic inorganic fine particles on the ink receiving layer, and forming a surface layer of the aqueous inkjet recording sheet. In the production method, the resin constituting the powder coating has a melting start temperature of 70 ° C. or more, and
It has a melt viscosity in the range of 20,000 to 1,000,000 poise at 00 ° C.

Preferably, the resin composition particles having an average particle diameter of 1 to 30 μm and an average particle diameter of 1 nm covering the surface of the resin composition particles are coated on the substrate while running the substrate in a predetermined direction. Dry coating of a powder coating comprising hydrophilic first inorganic fine particles having a surface temperature of from 1 μm and leading to a first heat fixing device comprising a fixing roller having a predetermined surface temperature and a pressure roller, To form an ink receiving layer made of the powder coating on the substrate, and then dry-coating hydrophilic second inorganic fine particles on the ink receiving layer, In the method for producing an aqueous inkjet recording sheet, a surface layer is formed by fixing the hydrophilic second inorganic fine particles on the ink receiving layer by applying pressure and heating between rollers to apply heat and pressure between rollers. The resin constituting the powder coating is 70 ° C. or higher Having a melting onset temperature of
It has a melt viscosity in the range of 20,000 to 1,000,000 poise at 100 ° C.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a powder coating is a particle composed of a resin, preferably a hydrophobic resin, more preferably a particle composed of a hydrophobic resin composition containing a colorant. Preferably, as described later, the hydrophobic resin composition particles are mixed with hydrophilic first inorganic fine particles, and the surface of the hydrophobic resin composition particles is coated with the inorganic fine particles. It is.

The resin constituting the powder coating has a role as a binder resin for combining various components of the powder coating into powder, and forms a resin layer as an ink receiving layer on a base material to form an aqueous solution. When recording characters and images with an inkjet ink, a colorant such as a dye or pigment that forms them is supported to enable the recording of the characters and images on a sheet.

As the resin constituting the powder coating material, various resins can be used without any particular limitation. Preferably, a hydrophobic resin is used. Such a hydrophobic resin is not particularly limited in a material constituting the same, but refers to a resin whose deionized water absorption is 0.1 times or less of its own weight, and specific examples include, for example, And a saturated polyester resin, a styrene-acrylic copolymer resin, an ethylene-vinyl acetate copolymer resin, and a styrene-butadiene copolymer resin.

Commercial products can be suitably used as the saturated polyester resin. Such commercial products include, for example, Byron 103, 200, 290, 600
(Manufactured by Toyobo Co., Ltd.), KA-1038C (manufactured by Arakawa Chemical Co., Ltd.), TP-220, 235 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), Diacron ER-101, ER-50
1, FC-172, FC-344, FC-714 (manufactured by Mitsubishi Rayon Co., Ltd.), Tufton NE-382, 111
0, 2155 (manufactured by Kao Corporation) and the like.

The styrene / acrylic copolymer resin is a copolymer of styrene and (meth) acrylic acid ester. Specifically, the (meth) acrylic acid ester includes, for example, ethyl acrylate and butyl acrylate. , Methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate and the like.

As such a styrene-acrylic copolymer resin, various commercial products can be suitably used. Commercially available products include, for example, Hymer SBM-100, UNI
-3000, TB-1800, TBH-1500 (manufactured by Sanyo Chemical Industries, Ltd.), CPR-100, 600B, 20
0, 300, XPA4799, 4800 (manufactured by Mitsui Chemicals, Inc.) and the like.

In the present invention, such a hydrophobic resin is used at a temperature of 100.degree.
Having a melt viscosity in the range of 0 poise, and 70 ° C. or higher,
Preferably, it has a melting onset temperature in the range of 70 to 95C and a glass transition temperature in the range of 45 to 60C.

If the melt viscosity of the hydrophobic resin at 100 ° C. is less than 20,000 poise, the resin may be excessively heated when the powder coating is pressed and heated between the fixing roller and the pressure roller of the heat fixing device. There is a possibility that the toner may easily flow, be exposed to the surface beyond the inorganic fine particles on the ink receiving layer, and may fuse (offset) with the fixing roller. On the other hand, when the melt viscosity at 100 ° C. of the hydrophobic resin exceeds 1,000,000 poise, the molten resin is too hard, and it is difficult to fix the inorganic fine particles on the ink receiving layer. In particular, according to the present invention, the hydrophobic resin preferably has a melt viscosity at 100 ° C. in the range of 20,000 to 600,000 poise.

Further, according to the present invention, when the melting temperature of the hydrophobic resin is lower than 70 ° C., the powder coating is completely melted when the powder coating is fixed to the substrate, and is continuously integrated. Forming a layer so that there are no gaps between the particles of the powder coating,
It is not possible to form an ink-receiving layer that is fused to each other while the powder coating has gaps partially between them.
On the other hand, when the temperature is higher than 95 ° C, hydrophilic inorganic fine particles are dry-coated on the ink receiving layer made of a powder coating containing such a resin, and the dry inorganic fine particles are guided to a heat fixing device, and are interposed between rollers. Even when heated under pressure, the powder coating does not melt enough to receive and fix the hydrophilic inorganic fine particles on the ink receiving layer, and fix the surface layer on the ink receiving layer. Incomplete, for example, the surface layer tends to peel off from the ink receiving layer.

Similarly, according to the present invention, when the glass transition temperature of the resin constituting the powder coating is lower than 45 ° C.,
When the powder coating material is melted and fixed on a substrate, the powder coating material cannot form an ink receiving layer that is fused to each other while having partial voids therebetween. On the other hand, when the glass transition temperature is higher than 60 ° C., the fixation of the surface layer on the ink receiving layer becomes incomplete.

According to the invention, the powder coating preferably contains a colorant. The colorant is preferably white, and for example, titanium oxide is preferably used, but is not limited thereto. The colorant gives the substrate the required ground color. The white colorant gives the substrate a white ground color. The coloring agent is used in an amount of usually 1 to 50% by weight, preferably 5 to 40% by weight in the obtained resin composition particles.

Further, in the present invention, the resin composition particles optionally contain an anti-offset agent. The anti-offset agent is, as described later, after the powder coating is dry-coated on the base material, heated, partially melted, having a gap between each other, and being fused to each other. It is blended with the resin as necessary so that no offset occurs when the ink receiving layer is formed. As an anti-offset agent,
Usually, various waxes having a melting point in the range of 50 to 150 ° C are preferably used. Specific examples include paraffin wax, polyolefin wax such as polyethylene and polypropylene, fatty acid metal salts, fatty acid esters, higher fatty acids, higher alcohols, and the like. Such an offset preventing agent is usually used in the range of 0.1 to 20% by weight, preferably 0.5 to 10% by weight in the obtained resin composition particles.

The resin composition particles according to the present invention may contain a filler in addition to the coloring agent. As the filler, for example, silica, calcium carbonate or the like is used.

The resin composition particles are obtained by mixing a resin with a coloring agent, an anti-offset agent and the like, if necessary.
Usually, about 100 to 200 ° C., preferably 130 to 1
Melted and kneaded at a temperature of about 80 ° C, cooled, pulverized,
Obtained by classification. According to the present invention, the resin composition particles have an average particle size in the range of 1 to 30 μm,
Preferably, it is in the range of 5 to 25 μm.

According to the present invention, such a resin composition particle may be used as it is as a powder coating, but preferably, such a resin composition particle and an average particle diameter of 1 nm to 1 nm are used.
The inorganic fine particles are mixed with hydrophilic inorganic fine particles of μm, the inorganic fine particles are adhered to the surfaces of the resin composition particles, and the surfaces of the resin composition particles are coated, and this is used as a powder coating. Hereinafter, the hydrophilic inorganic fine particles covering the surfaces of the resin composition particles as described above are referred to as hydrophilic first inorganic fine particles.

The first hydrophilic inorganic fine particles include:
Fine particles of inorganic oxides and inorganic carbonates are preferably used. Commercially available products can be easily obtained for such hydrophilic inorganic fine particles. Commercially available hydrophilic inorganic fine particles include, for example, Aerosil (registered trademark) 50, 90G, 130, which is anhydrous silica manufactured by Nippon Aerosil Co., Ltd.
200, 200V, 200CF, 200FAD, 30
0, 300CF, 380, OX50, TT600, MO
X80, MOX170, COK84, etc., aluminum oxide C, titanium dioxide P25, etc., Carplex (registered trademark) silica FPS-2, FPS- manufactured by Shionogi & Co., Ltd.
3, FPS-4, FPS-5, FPS-101, CS-
5, CS-7, BS-304F, BS-304N, etc., and further, anhydrous silica S13, V manufactured by Clariant Japan
15, N20, T30, T40 and the like. In addition, callite KT, which is calcium carbonate manufactured by Shiroishi Kogyo Co., Ltd., can also be used as the hydrophilic inorganic fine particles.

According to the invention, a powder coating as described above, particularly preferably as described above, has an average particle size of 1 to 30 μm.
m, and a powder coating comprising hydrophilic first inorganic fine particles having an average particle diameter of 1 nm to 1 μm covering the surface of the resin composition particles, and dry-coating the base material on the base material, By guiding to a heat fixing device consisting of a fixing roller and a pressure roller, applying pressure and heating between these rollers, and fixing the powder coating material together with the hydrophilic first inorganic fine particles,
A resin layer composed of a continuous powder coating can be formed on a substrate as an ink receiving layer while having gaps between the particles of the powder coating with the inorganic fine particles interposed therebetween.

According to the first method of the present invention, a powder coating and hydrophilic inorganic fine particles are dry-coated on a substrate while the substrate is running in a predetermined direction, and the substrate is led to a heat fixing device. hand,
An aqueous ink jet recording sheet is obtained by forming an ink receiving layer composed of the above powder coating on a substrate and fixing a surface layer composed of the hydrophilic inorganic fine particles on the ink receiving layer. Further, according to the second method of the present invention, while the base material is traveling in a predetermined direction, the powder coating is dry-coated on the base material, and the powder coating material is guided to the first heat fixing device, and An ink receiving layer made of a body paint is formed on a base material, and then, hydrophilic inorganic fine particles are dry-coated on the ink receiving layer, and guided to a second heat fixing device, where the hydrophilic inorganic fine particles are applied. Fine particles are fixed on the ink receiving layer to form a surface layer, thereby obtaining an aqueous inkjet recording sheet.

Here, according to the present invention, the substrate is usually moved in a predetermined direction in a range of 1 to 20 m / sec, preferably 2 to 1 m / sec.
While traveling at a constant speed in the range of 5 m / sec, the ink receiving layer and the surface layer are formed as described above.

Further, in the present invention, the heat fixing device includes a fixing roll which comes into contact with a powder coating material (or hydrophilic second inorganic fine particles described later) on a substrate and a pressure roll which supports the fixing roll from behind. The fixing roll has a surface temperature of 135 to 205 ° C. in advance, preferably 150 to 20 ° C.
It is heated to be in the range of 0 ° C. If necessary, the pressure roll is also heated to a surface temperature within the above temperature range.

In the present invention, the thickness of such an ink receiving layer is usually in the range of 1 to 100 μm, preferably in the range of 2 to 80 μm, and particularly preferably.
It is in the range of 5 to 50 μm. Further, according to the present invention, the voids between the powder coatings are usually from 1 nm to 20 nm.
The range is 0 nm.

The resin layer having such a unique structure is
According to the present invention, the first inorganic fine particles having hydrophilicity are blended at a required ratio with respect to the resin composition particles to form a powder coating,
This can be advantageously obtained by dry coating on a substrate, heating and fixing. According to the present invention, the proportion of the hydrophilic first inorganic fine particles is usually in the range of 0.5 to 10% by weight, preferably in the range of 1 to 9% by weight in the powder coating. , Most preferably 5 to
It is in the range of 8% by weight. However, optimally, it can be determined experimentally according to the respective average particle diameters of the powder coating composition and the inorganic fine particles used.

When the proportion of the hydrophilic first inorganic fine particles is too small, the inorganic fine particles are substantially interposed between the powder coatings when the powder coating is heated and fixed on a substrate. Form a continuous film, interposed between the particles of the individual powder coating, the powder coating has a gap, it is not possible to form a continuous resin layer, extending the aqueous The image obtained by inkjet recording is not sufficient in density. On the other hand, when the amount is too large, the fixability of the formed resin layer to the base material is poor. For example, when the base material is bent, the resin layer is easily peeled from the base material. Further, since the ratio of the resin composition particles in the powder coating is relatively small, the image density formed on the resin layer as the ink receiving layer may be insufficient.

When the average particle diameter of the hydrophilic first inorganic fine particles is smaller than 1 nm, even if a relatively large amount of the inorganic fine particles is used, the powder coating is continuously formed with a gap therebetween. When the resin layer cannot be formed and the average particle size is larger than 1 μm, after the powder coating composed of such inorganic fine particles and resin composition particles is dry-coated on the substrate, , When heated and melted in the heat fixing device,
It is difficult to fix on the substrate, and thus, the formed resin layer peels off from the substrate, causing defects in the obtained aqueous inkjet recording sheet, and thus obtaining a high quality inkjet recorded image Can not.

According to the present invention, the powder coating is thus dry-coated on the substrate, and then the hydrophilic second inorganic fine particles are dry-coated on the powder coating layer. After that, it is led to a first heat fixing device composed of a fixing roller having a predetermined surface temperature and a pressure roller, and heated under pressure between the rolls to form a powder coating layer on the base material and a The layer of the second inorganic fine particles is pressurized and heated integrally, and the particles of the powder coating material have the above-mentioned inorganic fine particles interposed therebetween, and have a gap, and a continuous resin layer is used as an ink receiving layer. An aqueous ink jet recording sheet can be obtained by forming the surface layer by forming the hydrophilic second inorganic fine particles on the ink receiving layer while forming it on the base material.

According to the invention, such a surface layer is usually in the range from 5 nm to 10 μm, preferably
The range is from 0 nm to 5 μm.

According to the present invention, as described above, the resin constituting the powder coating material has a melting start temperature of 70 ° C. or more, and has a melting temperature of 200 ° C. at 100 ° C.
Since a material having a melt viscosity in the range of 100 to 1,000,000 poises is used, even if it is guided to a heat fixing device and heated under pressure between rollers, the hydrophilic second
The inorganic fine particles do not slip on the ink receiving layer to form a so-called bank, so that a smooth surface layer made of hydrophilic second inorganic fine particles can be stably formed.

In the present invention, the hydrophilic second inorganic fine particles preferably have an average particle size in the range of 1 nm to 10 μm. When the average particle diameter of the hydrophilic second inorganic fine particles is larger than 10 μm, an image obtained from an aqueous ink jet recording sheet having a layer of such inorganic fine particles on the surface may lack accuracy, resulting in high quality. May not be able to give the recorded image of On the other hand, the second
Although the average particle diameter of the inorganic fine particles may be smaller than 1 nm, it is sufficient to use those having an average particle diameter of 1 nm or more from the viewpoint of availability. According to the present invention, the hydrophilic second inorganic fine particles have an average particle diameter in the range of 1 to 100 nm, particularly preferably in the range of 1 to 50 nm.

The hydrophilic second inorganic fine particles can be appropriately selected from the aforementioned hydrophilic first inorganic fine particles. Therefore, the first and second inorganic fine particles may be the same or different.

In the present invention, for example, an electrostatic spraying method is preferably used for dry-coating a powder coating on a base material and dry-coating hydrophilic second inorganic fine particles. This electrostatic spray method is a kind of powder coating,
Specifically, the fine powder coating material is conveyed by air to the tip of the spray gun, and a negative high voltage (for example, -50 to -9) is applied to the needle electrode incorporated in the tip of the spray gun.
0 kV) to make the powder coating negatively charged, while allowing the grounded electrode to follow the back surface of the base material, and thus, by the electric field existing between the spray gun and the grounded electrode, The charged powder coating material is transported to the base material and electrostatically attached.

FIG. 1 shows a preferred embodiment of the method of the present invention using such an electrostatic spray method. That is, roll 1
A continuous elongate base material (for example, plain paper) 12 rewound from 1 is guided into a booth 14 by a conveyor belt 13, where the first spray is formed by an electrostatic spray method as described later. The powder coating is dry-coated by the gun 15 and then similarly guided to a second booth (not shown), where the second inorganic fine particles are dry-coated by the second spray gun 16. The thus obtained laminated sheet is then led to a heat fixing device 19 including a fixing roller 17 having a predetermined surface temperature and a pressure roller 18, where it is heated under pressure, and An ink jet recording sheet 20 having a resin layer as an ink receiving layer having a special structure as described above and a second inorganic fine particle surface fixed and fixed thereon is obtained by melting a powder coating. Obtainable. The recording sheet is then wound on a roll or cut as appropriate.

The transport belt 13 has a grounded (ie, positive) electrode 2 on the back side along the substrate to be transported.
One. The powder paint is conveyed from the storage tank 22 to the spray gun 15 by compressed air, while a negative high voltage is applied by a DC power supply 23 to a needle electrode (not shown) incorporated at the tip of the spray gun. As a result, the powder coating is negatively charged. Thus, the powder coating is carried to and adhered to the substrate by the electric field present between the spray gun and the electrodes along the substrate on the conveyor belt. Dry coating of the second inorganic fine particles is performed in the same manner.

According to the present invention, as another method, a powder coating is dry-coated on a substrate, and the first coating is formed by a first heat fixing comprising a fixing roller having a predetermined surface temperature and a pressure roller. The ink-receiving layer was formed by applying pressure and heating between the rollers to form an ink-receiving layer, and then a second hydrophilic fine inorganic particle was further dry-coated on the ink-receiving layer. A second heat fixing device including a fixing roller having a predetermined surface temperature and a pressure roller is guided to the second heat fixing device, and heated under pressure between the rollers to remove the hydrophilic second inorganic fine particles from the ink receiving layer. The aqueous ink jet recording sheet can also be obtained by fixing on the surface and thus forming the surface layer.

Also in this case, according to the present invention, as described above, as the resin constituting the powder coating, 7
It has a melting onset temperature of 0 ° C. or higher, preferably in the range of 70 to 95 ° C.
By using a material having a melt viscosity in the range of 000000 poise, the hydrophilic second inorganic fine particles are placed on the ink receiving layer immediately before the fixing roller even if the film is heated under pressure by being guided to a heat fixing device. Since a so-called bank is not formed by slipping, a surface layer made of the hydrophilic second inorganic fine particles can be stably formed with a smooth surface.

In the present invention, the substrate is usually
Paper, synthetic paper, synthetic resin sheet and the like are preferably used.
If necessary, a substrate made of metal is also used. Paper is
The material is not particularly limited as long as it is made of ordinary cellulose fiber, and includes not only plain paper but also high-quality paper and coated paper. Examples of plain paper include ordinary PPC copy paper, calender-treated PPC copy paper to enhance the surface smoothness, and thermal transfer word processor paper and coated paper that have already been surface-treated. Can be mentioned. Examples of the synthetic resin sheet include sheets made of polyester, polyvinyl chloride, polyethylene, polypropylene, polyethylene terephthalate, polycarbonate, polyamide, and the like. Examples of the synthetic paper include those obtained by extruding a mixture of a polyolefin resin or another synthetic resin as a resin component, a required inorganic filler, and the like. In particular, by using paper as the base material, the powder-coated sheet and the ink-jet recording image-receiving sheet according to the present invention can be manufactured at low cost.

FIG. 2 schematically shows a cross section of a preferred embodiment of such an image receiving sheet for ink jet recording according to the present invention. Each powder coating material 31 is composed of hydrophobic resin particles 32 and hydrophilic first inorganic fine particles 33 covering the surface thereof. Such a powder coating material 31 is formed on a base material 34 by a resin layer 3 having a gap 36 while interposing a film 35 in which the first inorganic fine particles 33 are substantially continuous.
7 is formed as an ink receiving layer, and the first inorganic fine particles 33 are partially exposed on the surface of the resin layer 37. On such a resin layer 37, a surface layer 39 made of hydrophilic second inorganic fine particles 38 is further formed.

As described above, the aqueous ink jet recording sheet according to the present invention is preferably such that the powder coating composed of the resin composition particles having the surface coated with the hydrophilic first inorganic fine particles is partially coated therebetween. An ink receiving layer having a gap and fused to each other is provided on the substrate, and a surface layer made of second hydrophilic inorganic fine particles is provided on the ink receiving layer.

[0050]

Therefore, if the aqueous inkjet ink adheres to such an aqueous inkjet recording sheet,
First, the hydrophilic second inorganic fine particles forming the surface layer adsorb and capture the coloring agent composed of the dye or pigment in the ink, and the water in the ink is reduced by the hydrophilic second inorganic fine particles. It is adsorbed and quickly penetrates into the ink receiving layer along the film made of the hydrophilic first inorganic fine particles interposed between the particles of the powder coating, and is further captured by the first inorganic fine particles. Is absorbed.

Moreover, according to the present invention, as a resin constituting the powder coating material, a resin having a melting start temperature of 70 ° C. or more and a melt viscosity in the range of 20,000 to 1,000,000 poise at 100 ° C. is used. When fixing the second hydrophilic inorganic fine particles on the powder coating layer by the thermostat, the inorganic fine particles do not form a so-called bank immediately before the fixing roller. The surface layer can be formed smoothly.

Therefore, according to the aqueous ink jet recording sheet of the present invention, it is possible to form not only a clear and high-density image but also an accurate and distortion-free image, which is excellent in the absorbability and coloring of the aqueous ink. .

[0053]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited by these examples. The melt viscosity of the resin used was determined using a flow tester CFT-500 manufactured by Shimadzu Corporation using a pressurized plunger with a cross-sectional area of 1.0 cm ² , a die discharge portion length of 1.0 mm, a die discharge portion inner diameter of 1.0 mm, The measurement was performed under the conditions of a plunger pressing load of 98.07 N, a preheating time of 180 seconds, a preheating temperature of 50 ° C., and a heating rate of 2 ° C./min.

Example 1 (Preparation of powder coating) Styrene / acrylic copolymer resin (Hymer SBM-73F manufactured by Sanyo Chemical Industries, Ltd., 100 ° C.)
Melt viscosity at 400,000 poise, melting start temperature 9
60 parts by weight (0 ° C., glass transition temperature 57 ° C.) and white pigment (Titape A220, a titanium oxide manufactured by Ishihara Sangyo KK)
The mixture was melt-kneaded together with 35 parts by weight, cooled, pulverized and classified to produce hydrophobic resin composition particles having an average particle size of 11.0 μm. 95 parts by weight of the hydrophobic resin composition particles and 5 parts by weight of hydrophilic silica fine particles (200 manufactured by Nippon Aerosil Co., Ltd., average particle size: 12 nm) as the first hydrophilic inorganic fine particles were mixed and stirred to obtain a powder coating. Was prepared.

(Preparation of Inkjet Recording Paper and Presence or Absence of Bank Formation at the Time) As shown in FIG. 1, a long plain paper was used as a substrate at a speed of 5 m / sec in a predetermined direction. While running, the above-mentioned powder paint was sprayed on the surface with an electrostatic spray device and allowed to adhere, and the surface temperature was 160 ° C.
To a heat fixing device equipped with a fixing roll, and heated under pressure to fix the powder coating on the plain paper and simultaneously partially fuse the powder coating particles to each other, A resin layer having a thickness of 20 μm with a gap between them was formed as an ink receiving layer.

Next, hydrophilic silica fine particles (200, manufactured by Nippon Aerosil Co., Ltd., average particle size: 12 nm) as the second hydrophilic inorganic fine particles were sprayed onto the ink receiving layer by using an electrostatic spray device, and adhered. After that, it is led to a heat fixing device provided with a fixing roll having a surface temperature of 160 ° C. as described above, and heated under pressure to fix the second hydrophilic inorganic fine particles on the ink receiving layer. Then, a surface layer having a thickness of about 3 μm was formed. Thus, an aqueous inkjet recording paper according to the present invention was obtained.

In the production of such aqueous ink jet recording paper, when fixing the second hydrophilic inorganic fine particles on the ink receiving layer, the state of the second inorganic fine particles is observed, and the second inorganic fine particles are observed immediately before the fixing roller. It was visually examined whether or not the bank of the hydrophilic inorganic fine particles of No. 2 was formed. Table 1 shows the results.

(Inkjet Recording Characteristics) Using a commercially available inkjet printer (Epson PM-750C), inkjet recording was performed on the above inkjet recording paper, and the ink absorbency, that is, whether or not the ink was repelled, was visually observed. Investigated. The color development of the ink was measured using a Macbeth densitometer (model number RD-914) to measure the density of the darkest portion. Table 1 shows the results. The image density is practically 1.00 or more for yellow, 1.10 or more for magenta, 0.55 or more for cyan, and black for black.
It is preferably at least 1.45.

Example 2 An aqueous ink jet recording paper was obtained in the same manner as in Example 1 except that the surface temperature of the fixing roll was changed to 200 ° C. With respect to this, in the same manner as in Example 1, the presence / absence of a bank and the ink absorbency were examined when the second inorganic fine particles were fixed by the fixing roll. Table 1 shows the results.

Example 3 In Example 1, a styrene / acrylic copolymer resin (Hymer SBM-100 manufactured by Sanyo Chemical Industries, Ltd., melt viscosity at 100 ° C. of 20,000 poise A water-based inkjet recording paper was obtained in the same manner as in Example 1 except that the melting start temperature was 75 ° C. and the glass transition temperature was 45 ° C.). With respect to this, in the same manner as in Example 1, the presence / absence of a bank and the ink absorbency were examined when the second inorganic fine particles were fixed by the fixing roll. Table 1 shows the results.

Example 4 In Example 1, as the hydrophilic second inorganic fine particles,
Except for using hydrophilic silica fine particles (“Mizukasil P-78A, average particle size 3.3 μm” manufactured by Mizusawa Chemical Industry Co., Ltd.), in the same manner as in Example 1 for an aqueous inkjet having a surface layer with a thickness of 5 μm. The recording paper was obtained, and the presence or absence of a bank and the ink absorbency were examined when fixing the second inorganic fine particles by the fixing roll in the same manner as in Example 1. The results are shown in Table 1. Show.

Example 5 In Example 1, the hydrophilic second inorganic fine particles were
Aqueous inkjet recording having a surface layer having a thickness of 5 μm in the same manner as in Example 1 except that hydrophilic calcium carbonate fine particles (“Callite KT” manufactured by Shiraishi Industry Co., Ltd., average particle size: 2.6 μm) were used. I got the paper. With respect to this, in the same manner as in Example 1, the presence / absence of a bank and the ink absorbency were examined when the second inorganic fine particles were fixed by the fixing roll. Table 1 shows the results.

Comparative Example 1 An aqueous ink jet recording paper was obtained in the same manner as in Example 1 except that the surface temperature of the fixing roll was changed to 130 ° C. With respect to this, in the same manner as in Example 1, the presence / absence of a bank and the ink absorbency were examined when the second inorganic fine particles were fixed by the fixing roll. Table 1 shows the results.

Comparative Example 2 An aqueous ink jet recording paper was obtained in the same manner as in Example 1 except that the surface temperature of the fixing roll was changed to 210 ° C. With respect to this, in the same manner as in Example 1, the presence / absence of a bank and the ink absorbency were examined when the second inorganic fine particles were fixed by the fixing roll. Table 1 shows the results.

[0065]

[Table 1]

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of an apparatus configuration for manufacturing an ink jet recording sheet according to the present invention.

FIG. 2 is a schematic view showing a cross section of one embodiment of the ink jet recording sheet according to the present invention.

[Explanation of symbols]

11 ... roll, 12 ... long base material (for example, plain paper),
13: conveyor belt, 14: booth, 15: spray gun, 16: second spray gun, 17: fixing roller, 1
Reference numeral 8: pressure roller, 19: thermal fixing device, 20: recording sheet, 21: electrode, 22: storage tank, 23: DC power supply, 31
... powder paint, 32 ... hydrophobic resin particles, 33 ... hydrophilic first inorganic fine particles, 34 ... base material, 35 ... film, 36 ... gaps,
37: resin layer, 38: hydrophilic second inorganic fine particles, 39
... surface layer.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C056 FC06 2H086 BA13 BA15 BA33 BA36 BA45 BA53 4D075 AA09 AE03 BB29Z CA35 DA04 DC27 EA02 EB01 EB02 EB57

Claims (15)

[Claims] 1. A method in which a powder coating is dry-coated on a substrate while the substrate is running in a predetermined direction, and then hydrophilic inorganic fine particles are dry-coated on the substrate, and then a predetermined coating is performed. A first heat fixing device including a fixing roller having a surface temperature and a pressure roller is led to the first heat fixing device, and heated under pressure between the rollers to form an ink receiving layer made of the powder coating on a base material, In the method for producing an aqueous inkjet recording sheet in which the surface layer made of the hydrophilic inorganic fine particles is fixed on the ink receiving layer, the resin constituting the powder coating composition is set at 70 ° C.
A method having the above melting initiation temperature and a melt viscosity at 100 ° C in the range of 20,000 to 1,000,000 poise. 2. The method according to claim 1, wherein the powder coating has an average particle size of 1 to 30 μm, and the hydrophilic inorganic fine particles have an average particle size of 1 nm to 10 μm. 3. The method according to claim 2, wherein the hydrophilic inorganic fine particles are silica, alumina,
The method for producing an aqueous inkjet recording sheet according to claim 1, wherein the aqueous inkjet recording sheet is titanium oxide or calcium carbonate. 4. A resin composition particle having an average particle diameter of 1 to 30 μm and an average particle diameter of 1 nm covering the surface of the resin composition particle on the substrate while running the substrate in a predetermined direction. A powder coating comprising 1 μm of hydrophilic first inorganic fine particles is dry-coated, and then hydrophilic second inorganic fine particles are dry-coated thereon, followed by fixing with a predetermined surface temperature. A heat fixing device consisting of a roller and a pressure roller is introduced, and heated under pressure between the rollers to form an ink receiving layer made of the powder paint on a base material, and the ink receiving layer is formed on the ink receiving layer. In the method for producing an aqueous ink jet recording sheet for fixing a surface layer composed of hydrophilic inorganic fine particles, the resin constituting the powder coating has a melting start temperature of 70 ° C or more, and has a melting start temperature of 20000 to 100 ° C.
A method having a melt viscosity in the range of 1,000,000 poise. 5. The method according to claim 1, wherein the hydrophilic second inorganic fine particles have a particle diameter of 1 nm to 1 nm.
The method for producing an aqueous inkjet recording sheet according to claim 4, which has an average particle size of 0 µm. 6. The aqueous ink jet recording sheet according to claim 4, wherein the hydrophilic first inorganic fine particles are silica, alumina, titanium oxide or calcium carbonate. 7. The aqueous ink jet recording sheet according to claim 4, wherein the hydrophilic second inorganic fine particles are silica, alumina, titanium oxide or calcium carbonate. 8. A first heating device comprising a fixing roller having a predetermined surface temperature and a pressure roller, wherein a powder coating is dry-coated on the substrate while the substrate is running in a predetermined direction. It is led to a fixing device and heated under pressure between the rolls to form an ink receiving layer made of the powder coating on a substrate, and then dry-coated with inorganic fine inorganic particles on the ink receiving layer. And
In the method for producing an aqueous inkjet recording sheet for forming a surface layer by leading to a second heat fixing device and heating under pressure between rollers to fix the hydrophilic inorganic fine particles on the ink receiving layer, The resin constituting the powder coating is 7
A method having a melting onset temperature of 0 ° C. or higher and a melt viscosity at 100 ° C. in the range of 20,000 to 1,000,000 poise. 9. The method according to claim 8, wherein the powder coating has an average particle size of 1 to 30 μm, and the hydrophilic inorganic fine particles have an average particle size of 1 nm to 10 μm. 10. The method according to claim 8, wherein the hydrophilic inorganic fine particles are silica, alumina, titanium oxide or calcium carbonate. 11. A resin composition particle having an average particle diameter of 1 to 30 μm and an average particle diameter of 1 nm covering the surface of the resin composition particle on the substrate while running the substrate in a predetermined direction. A powder coating comprising 1 μm hydrophilic first inorganic fine particles is dry-coated and guided to a first heat fixing device comprising a fixing roller having a predetermined surface temperature and a pressure roller, and the above-mentioned roll-to-roll To form an ink receiving layer made of the powder coating on the substrate, and then dry-coating hydrophilic second inorganic fine particles on the ink receiving layer, A method for producing a water-based inkjet recording sheet in which a hydrophilic inorganic second inorganic fine particle is fixed on the ink receiving layer by applying pressure and heat between rollers to guide the heat-fixing device to a heat fixing device, and forming a surface layer. The resin constituting the powder coating is 7
A method having a melting onset temperature of 0 ° C. or higher and a melt viscosity at 100 ° C. in the range of 20,000 to 1,000,000 poise. 12. The method according to claim 11, wherein the hydrophilic second inorganic fine particles have an average particle size of 1 nm to 10 μm. 13. The method according to claim 1, wherein the hydrophilic first inorganic fine particles are silica, alumina, titanium oxide or calcium carbonate.
2. The aqueous inkjet recording sheet according to item 1. 14. The method according to claim 1, wherein the hydrophilic second inorganic fine particles are silica, alumina, titanium oxide or calcium carbonate.
13. The aqueous inkjet recording sheet according to 1 or 12. 15. A fixing roller having a surface temperature of 135 to 205.
The method for producing an aqueous ink jet recording sheet according to claim 1, wherein the temperature is in the range of ° C.