JP2002292997A - Ink jet recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording sheet which has a high color developability and in which the sheet can be double-side recorded without bringing about a conveying trouble in a printer. SOLUTION: The ink jet recording sheet comprises ink acceptive layers each containing an inorganic pigment on both side surfaces of a support. In this sheet, at least one side acceptive layer contains organic spherical particles. The mean particle size of the spherical particles is preferably in a range of 1 to 20 μm. Further, it is preferred that the thickness of the layer is 0.2 to 5 times as large as the mean particle size of the particles. It is preferred that the static frictional coefficient between the front surface and the rear surface is 0.7 or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording sheet for recording using ink.
More specifically, it has high color development and can record on both sides.
The present invention also relates to an ink jet recording sheet that does not cause a transport trouble in a printer.

[0002]

2. Description of the Related Art Ink-jet recording is a method of recording images and characters by flying fine droplets of ink and attaching them to a recording sheet such as paper according to various operating principles. It has features such as easy multi-coloring, great flexibility in recording patterns, and no need for development-fixing. It has rapidly spread in various uses as a recording device for various figures and color images, including Chinese characters. I have. Further, an image formed by the multi-color ink jet system can obtain a record comparable to multi-color printing by a plate making system or printing by a color photographic system. Further, in applications requiring a small number of copies, it is being widely applied to the field of full-color image recording because it is less expensive than photographic technology and printing technology.

As recording sheets used in the ink jet recording system, efforts have been made in terms of apparatuses and ink compositions in order to use high-quality paper and coated paper used for ordinary printing and writing. However, as the performance of the ink jet recording apparatus has been improved and the use thereof has been expanded, such as an increase in the speed, higher definition, and full color of the apparatus, higher characteristics have been required for the recording sheet. That is, the recording sheet has a high density of print dots, a bright and vivid color tone, quick absorption of ink, so that ink does not flow or overflow even when print dots overlap, High image reproducibility is required such that the diffusion in the direction is uniform and not excessively large, and the periphery is smooth and not blurred. That is, in order to obtain a good image, general high-quality paper or coated paper for printing is insufficient, and a recording sheet having a dedicated ink receiving layer of an ink jet recording system is indispensable.

In addition, while the demands for these characteristics are gradually becoming higher and stricter, an ink jet recording apparatus is inexpensive and has excellent image reproducibility such as sharpness and color reproducibility and color reproducibility at a personal computer level. The ink jet recording apparatus has been changed from a special recording apparatus used for a specific person to a general-purpose recording apparatus because it can be easily obtained. or,
Since images can be easily obtained in a quality comparable to printed matter and photographs, they are also being used as printers for self-made postcards and digital photographs.
In this case, the texture and feel of postcards and photographic prints are required.

[0005] When used for postcards,
In some cases, a destination or the like is also inkjet-recorded on the back surface, and it is desired that both surfaces have inkjet aptitude. Further, since a recording sheet capable of double-sided recording requires a small number of sheets to be used, there is a demand from the viewpoint of resource saving.

[0006] Further, with the diversification of uses, it is used for posters and POP arts, or provided with an adhesive layer on the back surface, and used for price display labels, product display (bar code) labels, quality display labels, It has come to be used for labels such as weighing display labels and advertising labels (stickers). Since these labels adhere well to a wide range of adherends and are easy to apply, they are combined with a sheet with heat-sensitive properties, magnetic properties, and offset printing suitability via an adhesive layer on the other side. It is also possible to add functions. Therefore, tickets, commuter passes, various cards, etc.
Applications for use with computers are also expanding.

When a printer using an ink jet system is used, one symbol may be printed on a plurality of ink jet recording sheets, or a plurality of symbols may be printed continuously. In such a case, the ink jet recording sheet may be fed one by one, but a method of setting a large number of sheets and feeding continuously is general. At this time, if the paper feedability or transportability of the ink jet recording sheet is poor, the paper is not fed to the printer, a double feed in which multiple sheets are fed in a stack, or the double fed ink jet recording sheet is jammed in the printer. Cause trouble that the printer stops. When a plurality of sheets are fed out of alignment, the printing of the symbol may extend over a plurality of sheets.

[0008] To deal with such troubles,
JP-A-162586, JP-A-6-278357 and the like disclose a method of improving the transportability by providing a back coat layer on the surface opposite to the ink jet recording surface.
However, in this method, since the surface on the side of the back coat layer does not have ink jet suitability, double-sided recording becomes impossible.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an ink jet recording sheet having high coloring properties, capable of recording on both sides, and causing no trouble in conveyance by a printer. It is.

[0010]

The object of the present invention is solved by the following means.

An ink jet recording sheet comprising an ink receiving layer containing an inorganic pigment provided on both surfaces of a support, wherein at least one of the ink receiving layers contains organic spherical particles. is there.

The organic spherical particles have an average particle diameter of 1 μm or less.
When the thickness is in the range of 20 μm, it is effective for reducing the coefficient of static friction between the front surface and the back surface of the ink jet recording sheet, which is preferable.

Furthermore, it is more effective if the thickness of the ink receiving layer is in the range of 0.2 to 5 times the average particle size of the organic spherical particles.

At this time, if the static friction coefficient between the front and back surfaces of the ink jet recording sheet is 0.7 or less,
This is preferable because transport trouble in the printer hardly occurs.

At this time, it is preferable that the inorganic pigment is synthetic amorphous silica.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The present invention is an ink jet recording sheet having a high color developing property, capable of performing both-side recording, and causing no trouble in conveyance by a printer.

Examples of the support that can be used in the present invention include resin films such as polyester films, polyolefin films and polyvinyl chloride, papers such as plain paper, coated paper and tracing paper, resin-coated paper, synthetic paper and adhesive paper. And an adhesive film. In addition, glass, aluminum foil, evaporated paper, evaporated film, non-woven fabric,
The support is not particularly limited as long as the support can be provided with an ink receiving layer such as a leather product or a ceramic product.

Inorganic pigments used in the ink receiving layer of the present invention include calcium carbonate, magnesium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, and aluminum silicate. Diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, alumina, alumina hydrate, pseudoboehmite, aluminum hydroxide, magnesium hydroxide, lithopone, zeolite, hydrohalosite, and the like. Among them, synthetic amorphous silica having a large pore volume is preferable.

The organic spherical particles used in the ink receiving layer in the present invention include polyamide resin, polyester resin, polycarbonate resin, polyether resin, polyolefin resin, polysulfone resin, polystyrene resin, polyvinyl chloride resin, polyvinylidene chloride. resin,
General organic spherical particles such as ethylene-vinyl acetate copolymer resin, polymethyl methyl methacrylate, ionomer resin, polyphenylene sulfide resin and styrene copolymer resin can be mentioned. At this time, the range of the average particle size from which high definition and high density image quality is obtained and sufficient effect of lowering the static friction coefficient is obtained is 1 μm to 20 μm, preferably 3 μm to 15 μm.

In the present invention, binders used in the ink receiving layer include starch derivatives such as oxidized starch, etherified starch and phosphated starch; cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose; casein, gelatin, soy protein, Polyvinyl alcohol or its derivatives; conjugated diene-based copolymer latex such as polyvinyl pyrrolidone, maleic anhydride resin, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer; polymer or copolymer of acrylate and methacrylate Acrylic polymer latex such as polymer; vinyl polymer latex such as ethylene-vinyl acetate copolymer; or functional group-modified polymer latex with functional group-containing monomer such as carboxyl group of these various polymers Those obtained by cationizing these various polymers with a cationic group, those obtained by cationizing the polymer surface with a cationic surfactant, and polymerizing under cationic polyvinyl alcohol to distribute the polyvinyl alcohol on the polymer surface. Polymerized in a suspension dispersion of cationic colloid particles, and the particles are distributed on the polymer surface; an aqueous binder such as a thermosetting synthetic resin such as a melamine resin or a urea resin; Polymer or copolymer resins of acrylates or methacrylates such as methyl methacrylate; synthetic resin binders such as polyurethane resins, unsaturated polyester resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral, and alkyd resins. Can be.

The amount of the binder in the ink receiving layer is as follows:
It is 5 to 70 parts by weight, preferably 10 to 50 parts by weight, based on 100 parts by weight of the pigment. If the amount is less than 5 parts by weight, the coating layer strength of the ink receiving layer will be insufficient, and if it exceeds 70 parts by weight, the ink absorbency will be undesirably reduced.

[0023] The coating amount of the ink-receiving layer, the type and amount of pigment and binder to be applied may vary depending on the type of the ink jet recording apparatus, 4g / m ² or more, preferably in the range of 7~20g / m ² It is. The coating amount of 1 g / m ² corresponds to a thickness of about 1 μm, and preferably ranges from 0.2 times to 5 times the average particle size of the organic spherical particles.

As a cause of the transport trouble in the printer, it was presumed that the static friction coefficient between the overlapping ink jet recording sheets was too high. In particular, in an ink jet recording sheet having an ink receiving layer provided on both surfaces of a support, a trouble is likely to occur because a back coat layer for lowering the friction coefficient cannot be provided.

The coefficient of static friction is measured according to JIS P8147. If this value exceeds 0.7, a transport trouble in the printer is likely to occur. Therefore, the pigment of the ink receiving layer, the binder, and the type of organic spherical particles,
It is necessary to adjust the static friction coefficient between the front surface and the back surface of the ink jet recording sheet to 0.7 or less by appropriately selecting the amount, the coating amount, the finishing method after the coating, and the like. However, if the coefficient of static friction is too low, problems such as the inability to stably stack a plurality of sheets occur when trying to stack a plurality of sheets.

In the present invention, it is also a preferable embodiment that the ink receiving layer contains a cationic water-soluble resin. The cationic water-soluble resin used in the present invention includes a secondary amine, a tertiary amine, and a quaternary ammonium salt such as polyethyleneimine salt, dimethylamine epihalohydrin condensate, polyvinylamine salt, polyallylamine salt, and polydimethylaminoethyl. Examples include methacrylate quaternary salts, polydiallyldimethylammonium salts, diallylamine acrylamide copolymer salts, and quaternary ammonium salts of polystyrene.

In the ink receiving layer, other additives such as a pigment dispersant, a thickener, a flow improver, a defoamer,
Foam inhibitors, release agents, foaming agents, penetrants, coloring dyes, coloring pigments, optical brighteners, ultraviolet absorbers, antioxidants, preservatives,
An anti-binder, a water-proofing agent and the like can be appropriately blended.

The ink-receiving layer in the present invention is formed on-machine or off-machine by using various devices such as various blade coaters, roll coaters, air knife coaters, bar coaters, rod blade coaters, curtain coaters, short dwell coaters and size presses. Painted on.

After coating and drying the ink receiving layer, a machine calender, TG
A calendar device such as a calendar and a soft calendar may be used.

[0030]

EXAMPLES The present invention will be described below with reference to examples, but is of course not limited thereto. Further, "parts" shown in the examples are parts by weight unless otherwise specified.

<Ink Absorbing Layer Coating Liquid A> The coating composition of the ink absorbing layer is a synthetic amorphous silica (Mizukasil P-78).
D: 100 parts by Mizusawa Chemical Industries, Ltd .; 45 parts of polyvinyl alcohol (PVA117: by Kuraray); cationic dye fixing agent (Sumiretz Resin 1001: by Sumitomo Chemical)
30 parts were mixed to prepare a coating liquid A.

<Ink Absorbing Layer Coating Liquid B> The coating composition of the ink absorbing layer is a synthetic amorphous silica (Mizukasil P-78).
D: 95 parts by Mizusawa Chemical Industry Co., Ltd .; 5 parts of polyolefin particles (Chemipearl W-300: average particle diameter 3 μm: manufactured by Mitsui Chemicals, Inc.); 45 parts of polyvinyl alcohol (PVA117: manufactured by Kuraray Co., Ltd.); cationic dye fixing agent ( 30 parts of Sumiretz Resin 1001: Sumitomo Chemical Co., Ltd.) were mixed to obtain a coating liquid B.

<Ink Absorbing Layer Coating Liquid C> The coating composition of the ink absorbing layer is a synthetic amorphous silica (Mizukasil P-78).
D: 95 parts by Mizusawa Chemical Industry Co., Ltd .; 5 parts of polyolefin particles (Chemipearl W-310: average particle size: 9.5 μm: manufactured by Mitsui Chemicals, Inc.); polyvinyl alcohol (PVA117:
45 parts of Kuraray Co., Ltd.) and 30 parts of cationic dye fixing agent (Sumiretz Resin 1001: Sumitomo Chemical Co., Ltd.) were mixed to prepare a coating liquid C.

<Ink Absorbing Layer Coating Liquid D> The coating composition of the ink absorbing layer is a synthetic amorphous silica (Mizukasil P-78).
D: 90 parts by Mizusawa Chemical Industry Co., Ltd .; 10 parts of polyolefin particles (Chemipearl W-300: average particle size 3 μm: manufactured by Mitsui Chemicals, Inc.); 45 parts of polyvinyl alcohol (PVA117: manufactured by Kuraray Co., Ltd.); 30 parts of Sumiretz Resin 1001: Sumitomo Chemical Co., Ltd.) were mixed to obtain a coating liquid D.

<Ink Absorbing Layer Coating Liquid E> The coating composition of the ink absorbing layer is a synthetic amorphous silica (Mizukasil P-78).
D: 90 parts by Mizusawa Chemical Industries, Ltd .; 10 parts of polyolefin particles (Chemipearl W-310: average particle size: 9.5 μm: Mitsui Chemicals, Inc.); polyvinyl alcohol (PVA11)
7: Kuraray Co., Ltd.) and 30 parts of a cationic dye fixing agent (Sumiretz Resin 1001: Sumitomo Chemical Co., Ltd.) were mixed to prepare a coating liquid E.

<Preparation of Ink-Jet Recording Sheet> The coating was carried out using a wire bar on a coated base paper (157 g / m ² basis weight, 6% talc filler, 9 g / m ² cob size, acidic paper) as a support. The coating liquids A to E were applied so as to have the surface dry coating amounts shown in Table 1 and dried, and the coating liquids A to E were also applied to the opposite surfaces on the back side as shown in Table 1. And dried to produce inkjet recording sheets for Examples and Comparative Examples shown in Table 1.

<Evaluation of Static Friction Coefficient> The static friction coefficient between the front surface and the back surface of the ink jet recording sheet was measured according to JIS P8147. After conditioning the sample for 24 hours at 20 ° C. and 65% RH, using a friction coefficient measuring device (slip tester: manufactured by Tester Sangyo) under a condition of 20 ° C. and 65% RH, weight 1 kg, moving speed Min 250
The measurement was performed under the condition of mm. The coefficient of static friction was calculated from the measured static friction force.

Μ _S = F _S / F _N μ _S : Coefficient of static friction F _S : Static friction force F _N : Weight of weight

<Evaluation of Printer Transportability> Using a commercially available ink jet printer (PM-800C, manufactured by Epson Corporation), 20 samples were set as one set, and 10 sets of printing by continuous paper feeding were performed. The judgment was made based on the following criteria. X is a level that poses a practical problem. ：: The occurrence rate of transport trouble is less than 1%. Δ: The occurrence rate of the transport trouble is 1% or more and less than 5%. X: The occurrence rate of the transport trouble is 5% or more.

<Coloring Property> Solid printing of black ink was performed using a commercially available ink jet printer (PM-800C: manufactured by Epson Corporation), and the optical reflection density of the printed portion was measured with a Macbeth densitometer (RD-919). . Practically, 1.50 or more is required.

<Backside Absorption> Using a commercially available ink jet printer (PM-800C: manufactured by Epson Corporation), solid printing of cyan ink, magenta ink and yellow ink was performed, and the printed portion and the unprinted portion were printed. Was visually determined. X is a level that poses a practical problem. ：: No bleeding at the boundary was observed. Δ: Bleeding at the boundary is observed. X: Bleeding at the boundary is remarkably observed.

[0041]

[Table 1]

When the ink receiving layers are provided on both sides of the support and at least one of the ink receiving layers contains organic spherical particles (Examples 1 to 16), the organic spherical particles are contained in both ink receiving layers. When not containing (Comparative Examples 1 to
The coefficient of static friction between the front and back surfaces is lower than in 3), and the printer transportability is good. Further, when the ink receiving layer is provided only on one side of the support (Comparative Examples 4 to 8), the surface without the ink receiving layer has insufficient color developability and ink absorbency.

[0043]

As described above, according to the present invention, it is possible to provide an ink jet recording sheet which has high coloring properties, can perform double-sided recording, and does not cause a transport trouble in a printer.

Claims (5)

[Claims] 1. An ink jet recording sheet comprising an ink receiving layer containing an inorganic pigment on both surfaces of a support, wherein at least one of the ink receiving layers contains organic spherical particles. 2. The organic spherical particles have an average particle size of 1 μm to 2 μm.
The ink jet recording sheet according to claim 1, wherein the thickness is in a range of 0 µm. 3. The ink jet recording sheet according to claim 2, wherein the thickness of the ink receiving layer is in the range of 0.2 to 5 times the average particle size of the organic spherical particles. 4. The ink jet recording sheet according to claim 1, wherein a coefficient of static friction between a front surface and a back surface of the ink jet recording sheet is 0.7 or less. 5. The ink jet recording sheet according to claim 1, wherein the inorganic pigment is synthetic amorphous silica.