JPH0441289A - Coating sheet - Google Patents

Abstract

PURPOSE:To obtain a coating sheet which is high in color forming density and further with no drop in color forming density as caused by aging by providing a layer containing cellulose beads in a binder at least on one side of a base material to eliminate horizontal diffusion of an ink with excellent absorbing and fixing property thereof. CONSTITUTION:This coating sheet is provided with a layer containing cellulose beads in a binder at least on one side of a base material. The base material herein usable is an ordinary paper or a thermoplastic resin film or a polyvinyl alcohol film or an oriented film thereof or the like. The cellulose beads are produced by a method wherein viscose is used as material, sprayed with two particle nozzles or the like and dried by hot air to form particles, which are treated by acid or the like to regenerate cellulose thereof. As a result, cellulose beads with a grain size of 0.1-1,000mum can be produced. Fine beads with the grain size thereof of about 1-20mum can be used preferably. As a degree of crystallization is as low as less than 40%, a layer can be formed with a high degree of swelling, excellent ink absorbing property and high color forming density.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to a coated sheet with excellent ink absorption, color development and fixing properties, and particularly to a coated sheet suitable for use on inkjet printer paper and general printing paper. The present invention relates to an engineered sheet and a method for manufacturing the same.

<Conventional technology> There are currently various printing methods such as sublimation printing, fusion printing, and electrophotographic printing, but compared to these printing methods, inkjet printing can print at higher speeds and in larger formats.
In addition, it has low running costs and excellent image clarity, making it promising.

Conventionally, the paper used for the above inkjet printing method has been paper that allows the pulp fibers to directly absorb ink, or paper that has silica, clay, calcium carbonate, diatomaceous earth, etc. fixed on the pulp fibers with a binder. Papers are known that have layers that absorb ink.

However, these conventional products have poor ink absorption properties, so when they are actually used, they do not provide satisfactory images, such as drying problems or ink spreading in the horizontal direction. Even with excellent absorbency, satisfactory color density could not be obtained.

Furthermore, in terms of changes in color density over time, there is a tendency for color density to decrease as time passes from the time of printing.
In terms of printability, ink set properties and oil absorption were not satisfactory.

<Problems to be Solved by the Invention> Therefore, as a photographic paper, it has excellent ink absorption and fixing properties, there is no ink diffusion in the lateral direction, and the color density is high, and the color density decreases due to aging. There is a great need for the development of something that does not exist.

<Means for Solving the Problems> In order to solve the above problems, the inventors of the present invention have conducted extensive research and found that paper provided with a layer containing cellulose beads has improved ink absorption and fixing properties. The present invention was completed based on the discovery that the ink is excellent, does not cause ink to spread in the lateral direction, has a high color density, and does not cause a decrease in color density due to changes over time.

That is, the coated sheet of the present invention is characterized in that a layer containing cellulose beads in a binder is provided on at least one side of the base material.

The present invention will be described below.

As the base material used for the coated sheet of the present invention, general paper, thermoplastic resin film, polyvinyl alcohol film, cellulose derivative film, stretched films thereof, etc. are used.

The above-mentioned thermoplastic resin film includes films such as polyethylene tereftate, polystyrene, polyvinyl chloride, polymethyl methacrylate, polyethylene, and polycarbonate, and films for improving the adhesion between the surface of these resin films and the ink receiving layer. A film provided with a subbing layer, a film subjected to corona discharge processing, etc. are used.

Next, the cellulose beads used in the present invention can be obtained by conventionally known methods such as dropping a cellulose solution into a poor solvent and coagulating it, or dispersing the cellulose solution into an emulsion and then coagulating it. things can be used.

However, the cellulose beads obtained by these manufacturing methods are high in cost and have a coarse particle size of about 50 to 1,000 μm. Therefore, the cellulose beads used in the present invention are manufactured by the method described below. Preferably.

That is, it is produced by using viscose as a raw material and spraying it using a two-particle nozzle or the like, then drying it with hot air to form particles, and then treating the particles with an acid or the like to regenerate cellulose. According to this manufacturing method,
By changing the average molecular weight of cellulose, the concentration in the cellulose xanthate aqueous solution, the spraying conditions, etc., cellulose beads with a particle size of about 0°1 to 1,000 μm can be produced, but in the present invention, Among these, those having a particle size of about 1 to 20 μm can be preferably used, and the cost is about one-tenth as low. In addition, although there are some shapes that are close to spherical and others that are slightly flattened, all of them have a smooth appearance, are porous, and have a low crystallinity of 40% or less, so when ink is absorbed, The degree of swelling is high, so it is possible to form a layer with excellent ink absorption and high color density.

On the other hand, the binder used in the present invention includes saturated copolymer polyester resin, vinyl chloride resin, vinyl acetate resin, vinyl chloride-vinyl acetate copolymer resin, acrylonitrile-styrene copolymer resin, vinyl acetate-acrylic copolymer resin, and polyamide. type resins, polyvinyl alcohol resins, their aqueous solutions, emulsion resins, etc. can be used.
The coated sheet of the present invention includes, on at least one side of the base material,
It is characterized by providing a layer containing the cellulose beads in the binder.

The above-mentioned coated sheet of the present invention can be manufactured by the manufacturing method described below.

First, the cellulose beads are dispersed in the binder. As a means for this dispersion, the above-mentioned binder 100
15 to 35 parts by weight of the above-mentioned cellulose beads are filled per part by weight, and dispersed using a known means such as a ball mill or a bot mill. The dispersion time is preferably about 20 to 25 hours.

Next, the coating liquid obtained by the above method is uniformly coated on the above substrate. The coating thickness is 5 to 40 .mu.m, preferably 35 to 40 .mu.m, and this step can also be carried out by appropriate well-known means.

Finally, the coated sheet of the present invention is obtained by drying, but if necessary, wetting agents, thickeners,
It goes without saying that a sizing agent or the like may be added, or a surfactant may be added in advance for the purpose of preventing static electricity, or may be applied after drying.

The coated sheet of the present invention thus obtained has excellent ink absorption, color development, and fixing properties, and also shows no decrease in color density due to changes over time. Therefore, it is suitable as photographic paper and printing paper. It is something.

<Effects of the Invention> As described above, the coated sheet of the present invention has excellent ink absorption properties, high color density, and no decrease in color density due to aging, making it extremely suitable for printing using the inkjet printing method. It can be used as a good photographic paper, and is also very good as a general printing paper with excellent ink setting properties and oil absorption.

Therefore, according to the present invention, it is possible to provide printing paper for inkjet printing that enables high-speed, large-sized printing and excellent image clarity, and general printing paper that has excellent ink setting properties, etc., at low running costs. It became.

<Example> Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 7% polyvinyl alcohol aqueous solution (manufactured by Kuraray Co., Ltd., PVA
-R-1130), 120 parts by weight of cellulose beads (
12 parts by weight of RCbeads 5-type (manufactured by Nisshinbo Co., Ltd.) [manufactured by a method of spray-drying viscose to form particles and further treating them with acid etc. to regenerate cellulose] was added as an additive. Thickener (manufactured by Rohm and Haas, 10% aqueous solution of EXP-300)
15 parts by weight, a wetting agent manufactured by San Nobuko Co., Ltd., 2272-R
5 parts by weight of -3N), 10 parts of sodium tripolyphosphate
% aqueous solution, 5 parts by weight, sizing agent (manufactured by Sanyo Chemical Co., Ltd., 5 parts by weight)
A-502-30) was added in an amount of 5 parts by weight and dispersed in a ball mill for 3 hours. This material was coated on a polypropylene film and dried at 90°C for 5 minutes.

The surface layer of the obtained coated sheet was white and the coating thickness was 30 μm.
It was m.

When I printed a solid black image on this sheet using a bubble jet printer (Canon, BJ-130J), there was no ink diffusion in the lateral direction, and when I measured the OD value, it showed a high density value of 1.5. Ta. Also, O after 10 days
When the D value was measured, it showed a numerical value of 1.5, and no decrease in concentration due to changes over time was observed.

Comparative Example 1 In the composition of Example 1, the same weight part of silica (Mizusawa Kagaku Co., Ltd., Mizusical P-78F) was added instead of cellulose beads, coated and dried in the above method. The surface layer of the obtained sheet was white and had a coating thickness of 30 μm.

When a solid black image was printed on this sheet using the bubble jet printer, the OD value showed a value of 1.5, but when the OD value was measured 10 days later, it showed a value of 1.38, which is due to changes over time. A decrease in concentration was observed. Further, when the printed portion was observed using a stereomicroscope with a magnification of 80 times, diffusion of the ink in the lateral direction was observed.

Example 2 Cellulose beads (manufactured by Nisshinbo Co., Ltd., RCbeads 5
-type) 100 parts by weight, polyvinyl alcohol (manufactured by Denki Kagaku Kogyo Co., Ltd., Denka Popal Ni-117E) 46.7
Parts by weight, 46.7 parts by weight of methyl acrylate butadiene latex (manufactured by Takeda Pharmaceutical Co., Ltd., Crossren EM45A),
Polyamide resin (manufactured by Sumitomo Chemical Co., Ltd., Sumirezu Resin 63
6) A coating liquid with a composition of 4 parts by weight and 66.7 parts by weight of water-soluble polyhydric alcohol was dispersed in a ball mill for 24 hours to form solid bones.
A 9.8% aqueous coating liquid was prepared. This coating liquid has a basis weight of 2B2.
A 5 g/m 2 base paper was coated with 23 g/m 2 (wet) on one side and dried with hot air at 100° C. for 2 minutes to obtain a coated paper.

Comparative Example 2 100 parts by weight of polyvinyl alcohol (manufactured by Denki Kagaku Kogyo Co., Ltd., Denka Popal Ni-17E), methyl acrylate butadiene latex (manufactured by Takeda Pharmaceutical Co., Ltd., Crossrene EM4)
5A) 100 parts by weight, 8.6 parts by weight of polyamide resin Sumitomo Chemical Co., Ltd., Sumirezu Resin 636), and 143 parts by weight of water-soluble polyhydric alcohol were dispersed in a ball mill for 24 hours to obtain a solid content of 12. A 3% aqueous coating solution was prepared. Using this coating liquid, coated paper was obtained in the same manner as in Example 2.

A quality test was conducted on the coated papers obtained in Example 2 and Comparative Example 2. Table 1 shows the results obtained regarding printability and oil absorption.

Table 1 Printing suitability test results (excellent) ◎ to △ (poor) *1 Check by solid printing with Mei Seisakusho, RI printing suitability tester *2 JIS paper and paperboard oil absorption test method P8130
-according to 1976

Claims (1)

[Scope of Claims] 1. A coated sheet comprising a layer containing cellulose beads in a binder on at least one side of a base material. 2. The coated sheet according to claim 1, wherein the cellulose beads have a particle size of 1 to 20 μm and a crystallinity of 40% or less. 3. The coated sheet according to claim 1 or 2, wherein the cellulose beads are produced using viscose as a raw material by a spray drying method.