JPS60189480A - Ink jet recording sheet - Google Patents

Abstract

PURPOSE:To enhance water resistance, light resistance or the like, by a method wherein a coated layer comprising a pigment, an adhesive mass or other additives is provided on the printing side of a sheet, and a water-soluble aluminum salt is provided in the coated layer or at the surface thereof. CONSTITUTION:The coated layer comprising a pigment, an adhesive mass or other additives is provided on the printing side of a sheet, and a water-soluble aluminum salt is provided in the coated layer or at the surface thereof to obtain a recording sheet for use in an ink jet recording method using an ink comprising at least one dye selected from water-soluble acidic dyes and direct dyes, water, a water-soluble organic solvent and a mildewproofing preservative. The water- soluble aluminum salt may be chloride, nitrate, sulfate, phosphate or the like, the chloride being optimum, and the amount of the salt adhered to the sheet is preferably 1-3g/m<2>.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an inkjet recording sheet, which can be used generally for recording media using a water-based printing method.

Conventional inkjet inks use dyes that are well soluble in water so that the direction of ink jetting does not change even after a long period of rest.

However, even after printing on a recording sheet, this causes the recorded characters and images to run or smear when the sheet gets wet with water or sweat. In order to solve this problem, the following proposals have been made in the past, but none of them could fully solve the problem.

1) As a method for making inkjet recorded images waterproof, an aqueous solution of a waterproofing agent is applied after recording (Japanese Patent Laid-Open No. 55-150
No. 396).

2) Similarly, as a method for making the recording sheet waterproof, there is a method in which a recording sheet is previously impregnated with a cationic polymer electrolyte (Japanese Patent Application Laid-open No. 84929/1983).

3) Similarly, as a method for making the recording sheet waterproof, there is a method in which the recording sheet contains chromium salt in advance and the dye is converted into a lake pigment.

However, method 1) has the disadvantage that the coating equipment for the aqueous solution of the water-resistant treatment agent is large and the image is likely to smear, and method 2) is not practical because even though water resistance improves, light resistance worsens. There wasn't.

Furthermore, method 3) uses a chromium salt, so there are concerns about the safety of the recording medium, and there is also a problem in that the color of the salt causes a large change in image tone.

Purpose This invention aims to incorporate a water-soluble aluminum salt into a recording sheet, and to improve water resistance by turning a water-soluble dye into a lake pigment, while at the same time not impairing the color tone, and to improve light resistance. The aim is to provide a recording sheet that improves performance.

Structure The structure of the present invention is a recording medium used in an inkjet recording method using an ink containing at least one dye selected from water-soluble acid dyes and direct dyes, water, a water-soluble organic solvent, and a preservative and antifungal agent. A sheet, characterized by having a coating layer containing a pigment, a binder, and other additives on the printing surface of the sheet 1, and containing a water-soluble aluminum salt in or on the coating layer. This is an inkjet recording sheet.

-F water-soluble aluminum salts include chlorides, nitrates,
Sulfates, phosphates, etc. are exemplified, but chlorides are the most useful, and the amount of adhesion to the sheet is from Ig/m2 to
30/m2 is appropriate. If lo/n+ is less than 2, the effect is insufficient, and if it exceeds 3 (1/m2), the color tone of the dye will change, and the aluminum chloride powder will fall off from the coating layer, making it difficult for inject printers. This reduces the reliability of the machine, the sheet itself becomes more hygroscopic, and the physical properties of the paper change.

Among the same water-soluble aluminum salts, nitrates, sulfates, phosphates, etc. have slightly lower water resistance and tend to turn yellow after being left for a long time.

To specifically explain the action of the above salts with reference to the accompanying drawings, Figure 1 shows the water resistance of an image when aluminum chloride is used in terms of the relationship between the amount of salt attached to the sheet and the discoloration rate of the image. .

FIG. 2 similarly shows the light resistance of the image as a relationship between the amount of aluminum chloride deposited on the sheet and the rate of discoloration of the image.

FIG. 3 shows the relationship between the hue change rate of the ink and the amount of aluminum chloride deposited on the sheet.

From the results shown in FIGS. 1 to 3 above, it can be seen that the appropriate amount of aluminum chloride to be deposited is 1 to 3 g/+++2.

Figure 4 shows the relationship between the type of salt and the water resistance (indicated by the fading rate) of the image when the same amount of water-soluble aluminum salt is used. This figure shows the relationship between the type of metal chloride, the water resistance of the image, and the hue error change rate when chloride is used.

From the results shown in Figures 4 and 5, it can be concluded that aluminum chloride is the most suitable salt among the water-soluble aluminum salts.

The present invention will be specifically explained below with reference to Examples and Comparative Examples.

Note that all amounts (parts) of each component to indicate the raw material composition are parts by weight.

Example 1 Silica powder 20 parts Light calcium carbonate powder 15 parts Casein 1 part Methyl methacrylate-butadiene copolymer latex (solid content) 15 parts PVA 3 parts Water 50 parts A liquid with the above composition was coated with a metal ring to determine the solid content. @
12 mm” on 80 μm thick high-quality paper,
It was dried at 0° C. for 7 minutes to form a coating layer.

Next, a 5wt% aqueous solution of aluminum chloride was applied using a bead coating method at a solid content coverage of 2.5o/m'.
It was dried at 10°C for 10 minutes, and then surface-treated in a heating and pressure calender at 80°C and 6-70 ko/cm to improve smoothness and produce inkjet recording paper.

This was designated as a sample (△).

Comparative Example 1 Recording paper for Infusiella 1 to 1 was produced in the same manner as in Example 1 except for the step of applying the aluminum chloride Swt % aqueous solution. This was designated as sample (B).

Comparative Example 2 Recording paper for Infusiera 1~ made in the same manner as in Example 1, except that a 6 wt % calcium chloride aqueous solution was used in place of the coating process of the 5 wt % aluminum chloride aqueous solution in Example 1, with a solid content coverage of 3 g/m 2 And so. This was designated as sample (C).

Comparative Example 3 Instead of applying the 5 wt % aqueous solution of aluminum chloride in Example 1, a 4 wt % aqueous solution of tin chloride was applied at a solid content of 2 o/w.
m2, and the other conditions were the same as in Example 1. This inkjet recording paper was designated as sample (D).

Example 2 An aluminum chloride Swt% aqueous solution was applied with a roller to an inkjet recording paper made by Mitsubishi Paper Industries with a size degree of 2 seconds and a whiteness degree of 80, and the solid content adhesion was 11.2 (1/C1, 100
It was dried at ℃ for 12 minutes. This inkjet recording paper was designated as sample (E).

Comparative Example 4 The inkjet recording paper of Example 2 without the aluminum chloride treatment was designated as sample (F).

Example 3 Silica powder 15 parts Magnesium carbonate powder 5 parts Calcium silicate 3 parts Vinyl acetate polymer latex (solid content) 10 parts Polyvinylpyrrolidone 3 parts Etherified starch 2 parts Water 45 parts The above composition was thoroughly dispersed and dispersed. The liquid was coated with a metering bar to a thickness of 80 μm with a solid content of 10 g/l112.
Coat on thick high-quality paper, dry at 105℃ for 10 minutes,
A single layer was formed.

Next, a 7 wt% aqueous solution of aluminum nitrate was coated with a bead coating method to obtain a solid content of 3 a/m2, and this recording paper was used as a sample (G).

The above samples were evaluated using the following evaluation method.

1. Water resistance evaluation method: Immerse in warm water at 30°C for 1 minute, measure the reflection density after immersion, and evaluate by the rate of discoloration after immersion.

2. Light resistance evaluation method A carbon arc lamp is irradiated for 4 hours using a fade meter, and the color fading rate after irradiation is evaluated.

3. Color tone evaluation method Hue error is evaluated using the GATF color evaluation method.

Inkjet printing here is]-I! IJp -4
The test was carried out using 100 machines, and an ink having the following composition was used.

=9- C, 1, acid red g2 3Wj% glycerin 1
0wt% Diethylene glycol 20wt% Preservative and fungicide PULLTOP 33 0.5wt% Pure water Remaining
As explained above, according to the present invention, even when a water-soluble dye is turned into a lake pigment, not only the color tone of the dye is not impaired, but also the light resistance is improved.

[Brief explanation of drawings]

10- FIG. 1 is a graph showing the water resistance of an image in terms of the relationship between the amount of aluminum chloride attached to the sheet and the fading rate of the image. FIG. 2 is a graph showing the light resistance of an image in terms of the relationship between the amount of aluminum chloride applied and the rate of discoloration of the image. FIG. 3 is a graph showing the relationship between the hue error change rate of ink and the amount of aluminum chloride deposited on the sheet. FIG. 4 is a graph showing the relationship between the type of aluminum salt and the water resistance of an image. FIG. 5 is a graph showing the relationship between the chlorides of different metals and the water resistance and hue error change rate of images. Patent applicant Rico Co., Ltd. - Agent Patent attorney Hide Komatsu Agent Patent attorney Hiroshi Asahi 11-

Claims (1)

[Claims] A recording sheet used in an inkjet recording method using an ink containing at least one dye selected from water-soluble acid dyes and direct dyes, water, a water-soluble organic solvent, and a preservative and antifungal agent, the printing surface of the sheet An inkjet recording sheet comprising a coating layer containing a pigment, a binder, and other additives, and a water-soluble aluminum salt contained in or on the coating layer.