JPH1035093A - Ink jet recording sheet and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance adhesion and scratch resistance of an ink jet recording sheet immediately after printing by forming an ink receiving layer containing at least high water absorption macromolecules, porous microparticles, a binder and a getting agent on a basic material sheet thereby increasing the getting rate of ink while sustaining the conventional features. SOLUTION: A transparent white plastic film, paper or cloth can be used as a basic material sheet on which an ink receiving layer containing at least high water absorption macromolecules, porous microparticles, a binder and a getting agent is formed. The high water absorption macromolecules serve to suck an ink instantaneously and to retain the sucked ink and polymethacrylic acid is preferably employed. The binder serves to enhance adhesion to the surface of the basic material sheet and polyvinyl alcohol is preferably employed. The porous microparticles are employed to adsorb the gelling agent and a dye ink and silica is preferably employed. Tertiary amine is preferably employed as the gelling agent.

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, and more particularly, to an ink jet recording sheet capable of completing gelation of a sol-containing ink jet ink in a short time.

[0002]

2. Description of the Related Art Ink jet printers are widely used not only as output devices such as personal computers but also as means for printing on media of various materials. Currently, widely used inks for inkjet printers are dyes composed of organic compounds that are soluble in water and other solvents. Dyes and naphthoquinone dyes.

[0003] Dyes are soluble in water and other solvents, so that they have the advantage of being able to form a very thin colored layer and to have a transparent color tone. There is a disadvantage that the color is discolored by the irradiation of upper ultraviolet rays. In addition, since it is made of an aqueous dye, there is a problem that the surface gloss and scratch resistance of the obtained printed matter are poor.
Therefore, in order to obtain good surface gloss and scratch resistance, a surface treatment with an acrylic resin or the like is also performed after inkjet printing. However, in the case of performing a surface treatment with an acrylic resin or the like, there is a disadvantage that an extra step is required, resulting in an increase in cost. Also,
A pigment may be used as an ink for an inkjet printer, but the pigment cannot be used as an ink for an inkjet printer because the pigment has a large particle size.
In addition, a clear color or a transparent color cannot be obtained with a pigment.

Accordingly, the present inventors have proposed an ink containing sol fine particles of an inorganic oxide and / or hydroxide in which a dye is uniformly dispersed. When this ink is ejected from the nozzle of the ink jet printer, the sol of the oxide and / or hydroxide gels upon contact with the atmosphere, and has good water resistance, light resistance, surface gloss, scratch resistance and adhesion. Have. However, in the conventional inkjet recording sheet,
The gelation speed of this ink is not sufficient, and there is a problem that the adhesion and the scratch resistance immediately after printing are insufficient.

Accordingly, it is an object of the present invention to provide an ink jet recording sheet having a high ink gelation rate and good adhesion and abrasion resistance immediately after printing while maintaining the characteristics of the conventional ink jet recording sheet. It is.

[0006] Another object of the present invention is to provide a method for producing such an ink jet recording sheet.

[0007]

Means for Solving the Problems As a result of intensive studies in view of the above object, the present inventors have found that inorganic acids, organic acids, metal hydroxides,
Forming an ink-receiving layer containing a gelling agent such as amines on a base sheet increased the gelation rate of the sol in the ink and significantly improved the scratch resistance immediately after printing. Invented the invention.

That is, the ink jet recording sheet of the present invention is an ink jet recording sheet for recording with an ink containing sol fine particles of an inorganic oxide and / or a hydroxide in which a dye is uniformly dispersed. And an ink receiving layer including at least a superabsorbent polymer, porous fine particles, a binder, and a gelling agent.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

[1] Ink jet recording sheet The ink jet recording sheet of the present invention is formed on a base sheet.
An ink receiving layer containing at least a superabsorbent polymer, porous fine particles, a binder, and a gelling agent is formed. Hereinafter, each component will be described in detail.

(1) Base sheet The base sheet used in the present invention is not particularly limited as long as it can coat the ink receiving layer, and is not particularly limited. Or a cloth can be used, and when used as an OHP image forming sheet material, it is preferable to use a transparent plastic film such as polypropylene or polyethylene terephthalate. Also, the thickness of the base sheet is not particularly limited, and may be appropriately selected according to the purpose of use of the sheet.

(2) Superabsorbent polymer The superabsorbent polymer used in the present invention is for instantly absorbing and retaining ink, and is composed of polyacrylic acid, polystyrenesulfonic acid, polyvinylsulfonic acid, One or more superabsorbent polymers selected from the group consisting of polymethacrylic acid and salts thereof can be used. Among them, it is particularly preferable to use polymethacrylic acid or the like.

(3) Binder The binder is used to improve the fixability to the surface of the substrate sheet because the water-absorbing polymer alone does not form a film on the substrate sheet. Polyvinyl alcohol, polyethylene oxide, polypropylene oxide, polyvinyl pyrrolidone, polyacrylamide,
One or more binders selected from the group consisting of a water-soluble polyester resin, polyvinyl acetate, a water-soluble polyamide resin, polyethylene imine, polyethylene polyamine, and polyallylamine can be used. Among them, it is particularly preferable to use polyvinyl alcohol or the like.

(4) Porous fine particles Porous fine particles are used for adsorption of a gelling agent and a dye ink. Therefore, fine particles having high adsorptivity, that is, fine particles having high specific surface area are preferable. Preferred specific surface area of the fine particles is 100 to 400 m ² / g. The average particle size of the fine particles is 50 nm or less, preferably 10 to 20 nm. Examples of such porous fine particles include silica, alumina, titania, zirconia and the like, and among them, silica is particularly preferable.

(5) Gelling agent The gelling agent has an action of accelerating the gelation of the sol-containing ink printed on the recording sheet. Although it depends on the type of sol used in the ink, it is generally at least one selected from the group consisting of inorganic acids, organic acids and their anhydrides, metal hydroxides, and amines. Hydrochloric acid, sulfuric acid, nitric acid etc. as inorganic acids, phthalic anhydride, maleic anhydride etc. as organic acids and anhydrides thereof, sodium hydroxide, lithium hydroxide etc. as metal hydroxides, ammonia, aniline, benzylamine etc. as amines Primary, secondary, or tertiary amines and the like can be mentioned, and it is particularly preferable to use tertiary amines.

In the present invention, in addition to the above-mentioned composition, known additives can be further added as required. Examples of such additives include a dispersant, a water retention agent, a thickener, a defoaming agent, a release agent, a colorant, a waterproofing agent, a wetting agent, and a fluorescent dye.

[2] Manufacturing method of ink jet recording sheet A solvent was added to the above-mentioned composition and mixed to prepare a coating liquid. The solvent is at least one selected from water, alcohol, glycols and the like. The mixing ratio is 1 for the entire coating liquid.
It is preferable that the superabsorbent polymer be 1% to 30% by weight, 5% to 30% by weight of a binder, 40% to 90% by weight of porous fine particles, and 0.2% to 20% by weight of a gelling agent.
Superabsorbent polymer 5-10% by weight, binder 5-10% by weight, porous fine particles 60-80% by weight, gelling agent 1-1
It is particularly preferred to be 0% by weight.

The obtained coating solution is dried (at a temperature of 100 ° C.).
(Approximately 150 ° C., 3 to 15 minutes) within a range of 1 to 50 μm, such as a well-known applicator method, bar coater method, roll coating method, spray coating method, die coating method, lip coating method, The upper surface of the substrate sheet is applied using an air knife coating method. This is because if the film thickness is less than 1 μm, a clear image is not formed, and if the film thickness exceeds 50 μm, the base sheet is curled and cannot be used.

Further, in this case, it is possible to provide a primer layer between the substrate sheet and the ink receiving layer in order to improve the adhesion between the ink receiving layer and the substrate sheet. As the primer layer, one or more primers selected from polyurethane, polyester, and polyacrylic groups can be used.

[0019]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.
The inks for ink jet printers used in the examples and comparative examples were prepared in the following reference examples.

Reference Example A homogeneous solution having the following composition was prepared. Tetraethoxysilane Si (OC ₂ H ₅ ) ₄ 34% by weight Dye ⁽¹⁾ (based on solid content) 10% by weight Methanol 30.5% by weight 2N aqueous ammonia 0.5% by weight Water 25% by weight 100.0% by weight Note: (1) Use The types of dyes thus obtained were as follows. A. Cyan dye (Solvent Blue 78, "Sumiplast Blue GP" manufactured by Sumitomo Chemical Co., Ltd.). B. Magenta dye (Solvent Red 145, "Sumiplast Red 3B" manufactured by Sumitomo Chemical Co., Ltd.). C. Yellow dye (Solvent Yellow 54, "Sumi plast Lemon Yellow HGN" manufactured by Sumitomo Chemical Co., Ltd.).

The above solution was heated and stirred at 30 ° C. for 2 hours to obtain dispersions A, B and C (containing dyes A, B and C, respectively) of 10% by weight of silica sol (average particle size: 10 nm). 5 parts by weight of ethylene glycol was mixed with each of the obtained silica sol dispersions to prepare an ink.

Example 1 A 100 μm-thick polyester film (trade name: U2, manufactured by Teijin Limited) was used as a base material. A coating solution having the following composition was applied to this film, and the film thickness after drying was: 10μ
m after coating with an applicator so that
Drying was performed at 20 ° C. for 10 minutes to obtain a colorless and transparent ink jet recording sheet.

Composition of coating liquid Superabsorbent polymer: 50 g of AC-30H, Nippon Pure Chemical Co., Ltd. Binder: 50 g of PVA-117 (10% solution), Kuraray Co., Ltd. Porous fine particles: Aerosil 200, Nippon Aerosil Co., Ltd. Particle size 12nm 80g Gelling agent: Koei Chemical Industry Co., Ltd. Benzylamine 5g Solvent: Water 200g Isopropyl alcohol 200g

Using the ink jet printer (MJ-500C) manufactured by Epson Co., Ltd., the thus obtained ink jet printing sheet of the present invention was printed with the ink prepared in Reference Example. The following test was performed on the sample immediately after printing. Table 2 shows the test results.

(1) Light fastness test: Dew cycle sunshine super long life weather meter “WE
Using L-SUN-DC "(manufactured by Suga Test Instruments Co., Ltd.), the test was performed under the condition of an exposure time of 240 hours without rainfall. The evaluation is as follows. A: Very good (no fading was observed after 240 hours). ：: Good (fading was slightly observed after 240 hours). Δ: Normal (fade similar to printed matter of a normal inkjet printer was observed after 240 hours).

(2) Surface gloss test: The surface gloss of the printed matter on the polyester film was visually observed. The evaluation is as follows. ◎: very good (had the same gloss as in the photograph) ：: good (slightly inferior to the photograph but glossy) Δ: Normal (substantially no gloss).

(3) Scratch resistance test: The surface gloss was visually observed, and the abrasion resistance was determined by the presence or absence of scratches by nails. The evaluation is as follows. ◎: very good (scratch was not formed at all) ：: good (scratch scarcely formed) Δ: Normal (scratch was easily formed).

(4) Adhesion force test: The sample printed on the glass plate was cut with a cutter knife at intervals of 1 mm to form 100 meshes, and after sticking a cellophane tape, peeled and remained. The cells were counted (cross hatch test method). The evaluation of the adhesion by this method is as follows. ◎: Very good (100 residual meshes). ：: Good (50 to 99 residual meshes). Δ: Normal (less than 50 residual meshes).

Comparative Example 1 A 100 μm-thick polyester film (manufactured by Teijin Limited, trade name: U2) was used as a base material. A coating solution having the following composition was applied to this film, and the film thickness after drying was: 10μ
m after coating with an applicator so that
Drying was performed at 20 ° C. for 10 minutes to obtain an inkjet recording sheet.

Composition of coating liquid Superabsorbent polymer: 50 g of AC-30H, Nippon Pure Chemical Co., Ltd. Binder: 50 g of PVA-117, Kuraray Co., Ltd.

The ink jet printing sheet thus obtained was printed with the ink prepared in Reference Example, using an ink jet printer (MJ-500C) manufactured by Epson Corporation. For the sample immediately after printing, (1) light resistance test, (2) surface gloss test,
(3) Scratch resistance test and (4) adhesion test were performed. Table 2 shows the test results.

Table 2 Example No. Retention of reflection density Light resistance Surface gloss Scratch resistance Adhesion Example 1 ○ ◎ ○ ◎ ◎ Comparative Example 1 △ △ ○ △ △

As described above, with the ink jet recording sheet of Example 1, a printed matter having excellent scratch resistance and adhesion was able to be produced.

Although the present invention has been described with reference to specific examples,
The present invention is not limited to this, and various changes can be made within the scope of the present invention.

[0035]

As described in detail above, since the ink jet recording sheet of the present invention contains a gelling agent, it is possible to promote the gelation of the ink containing the sol, and to achieve the adhesion immediately after printing. A recording sheet having excellent properties and scratch resistance can be obtained.

Claims (7)

[Claims] 1. An ink jet recording sheet for recording with an ink containing sol fine particles of an inorganic oxide and / or hydroxide in which a dye is uniformly dispersed, wherein at least a superabsorbent polymer is provided on a base sheet. An ink jet recording sheet comprising an ink receiving layer containing porous fine particles, a binder and a gelling agent. 2. The ink jet recording sheet according to claim 1, wherein the gelling agent is at least one selected from the group consisting of inorganic acids, organic acids and anhydrides thereof, metal hydroxides, and amines. An ink jet recording sheet characterized by the above-mentioned. 3. The ink jet recording sheet according to claim 1, wherein the porous fine particles are at least one selected from the group consisting of silica, alumina, titania, and zirconia. . 4. The ink-jet recording sheet according to claim 1, wherein the superabsorbent polymer is
An ink jet recording sheet comprising at least one selected from the group consisting of polyacrylic acid, polystyrene sulfonic acid, polyvinyl sulfonic acid, polymethacrylic acid, and salts thereof. 5. The ink jet recording sheet according to claim 1, wherein the binder is polyvinyl alcohol, polyethylene oxide, polypropylene oxide, polyvinyl porolidone, polyacrylamide, a water-soluble polyester resin, polyvinyl acetate, An ink jet recording sheet comprising at least one selected from the group consisting of a water-soluble polyamide resin, polyethylene amine, polyethylene polyamine, and polyallylamine. 6. The ink jet recording sheet according to claim 1, wherein the base sheet is any one of a plastic film, paper, glass, and cloth. 7. A method for producing an ink jet recording sheet for recording with an ink containing sol fine particles of an inorganic oxide and / or hydroxide in which a dye is uniformly dispersed,
A method comprising mixing porous fine particles impregnated with a gelling agent, a superabsorbent polymer, and a binder, and laminating the mixture on a substrate sheet.