JPH11157205A - Recording sheet for aqueous ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording sheet for an aqueous ink which shows a high light transmission in an ink image receiving layer and is lustrous, and allows easy fixing of pigment so that the incidence of pigment ink bleeding is low. SOLUTION: An ink image receiving layer 3 is formed on a base material 2 by coating an urethane resin composition. An urethane resin shows superb pigment fixing properties, so that even when a pigment ink is used for printing on a recording sheet for an aqueous ink, an ink bleeding can be suppressed. Consequently, a filler no longer need be blended into the ink image receiving layer 3 and the light transmission and surface luster of the layer 3 are improved. In addition, it is possible to enhance the color developing properties of the recording sheet 1 for an aqueous ink by blending the ink image receiving layer 3 with a cationic surfactant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording sheet for aqueous ink used for recording with aqueous ink such as ink jet recording.

[0002]

2. Description of the Related Art Ink-jet recording is free of noise, is capable of high-speed printing, is capable of performing multicolor printing by using a plurality of nozzles, and is low-cost. It is rapidly spreading as an information output device. A water-based ink is preferably used as the ink for ink-jet recording in terms of safety, recording characteristics, and the like. Conventional aqueous inks are generally obtained by dissolving dyes, binders, solvents, additives and the like in water. In addition, as this water-based ink, those having relatively low drying properties are mainly used to prevent clogging of jet nozzles. Therefore, the recording sheet for water-based ink that receives the water-based ink needs to be excellent in the absorbability of the water-based ink and the initial drying property. In order to improve the absorbability of the aqueous ink, the ink receiving layer of the recording sheet for the aqueous ink is composed of a water-soluble resin such as polyvinyl alcohol, polyvinylpyrrolidone, hydropropylmethylcellulose, starch, casein, and gelatin and a superabsorbent resin. I have.

A water-based ink using the above-mentioned dye has a disadvantage that the weather resistance is insufficient. Therefore, a water-based ink having improved light fastness by using a pigment instead of the dye (hereinafter referred to as a “pigment-based ink”) Is also being used. However, since the pigment has a large particle size, it is difficult to fix the pigment on the ink image receiving layer, and there is a problem that an image is blurred.

In order to solve this problem, as shown in FIG. 2, an ink image receiving layer 13 is provided on a substrate 12, and the ink image receiving layer 13 has silica, colloidal silica, clay,
Recording sheet for aqueous ink 11 containing a filler such as talc, silicon earth, calcium carbonate, aluminum silicate, alumina, zinc oxide, synthetic zeolite, calcium sulfate, etc.
Has been proposed. By blending these fillers, the surface of the ink image receiving layer 13 can be made porous,
The pigment is easily fixed physically, thereby suppressing bleeding of the image. In the case of a recording sheet 11 for an aqueous ink which requires transparency, such as for an overhead projector (hereinafter referred to as "OHP"), a transparent resin sheet or the like is used as the substrate 12, and a normal aqueous ink for recording is used. In the case of the recording sheet 11, the base 12 is made of white or other colored opaque paper, synthetic resin film, or the like.

[0005]

However, if a filler is blended in the ink image receiving layer 13, light rays passing through the ink image receiving layer 13 will be blocked by the filler. For this reason, in the case of a transparent water-based ink recording sheet 11 for OHP or the like, there is a problem in that the transmittance is insufficient and the OHP image becomes dark. Further, in the case of the recording sheet 11 for a normal aqueous ink for recording, the color tone of the base material is hardly reflected, and the color tone becomes cloudy. For example, when the base material is white paper, the whiteness is reduced. Problem. Further, by adding a filler to make the surface of the ink image receiving layer 13 porous, there is a problem that the glossiness of the aqueous ink recording sheet 11 is reduced.

The present invention has been made in view of these problems, and is intended for aqueous inks in which the ink image-receiving layer has a high light transmittance, is glossy, and has a low pigment bleeding because the pigment is easily fixed. It is intended to provide a recording sheet.

[0007]

Means for Solving the Problems The invention made to achieve the above object is a recording sheet for aqueous ink, in which an ink image receiving layer mainly composed of a urethane resin is formed on a base material. (Claim 1).

According to the present invention, since the urethane resin having excellent fixability of the pigment is used for the ink image receiving layer, the bleeding of the pigment ink can be suppressed. For this reason, the filler can be omitted from the ink image-receiving layer or the amount of the filler can be suppressed, and the light transmittance of the ink image-receiving layer can be increased. Therefore, in the case of a transparent aqueous ink recording sheet, the light transmittance thereof can be increased, and in the case of a normal recording aqueous ink recording sheet, a vivid color tone that reflects the color tone of the base material can be obtained. it can. Furthermore, the surface of the recording sheet for aqueous ink can be made flat, and its glossiness can be enhanced.

In the present invention, if a cationic surfactant is blended in the ink image-receiving layer, the color developability of the recording sheet for aqueous ink can be improved. The amount of the cationic surfactant is preferably 0.1 to 90 parts by weight based on 100 parts by weight of the urethane resin (Claim 3).

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of a recording sheet 1 for aqueous ink according to an embodiment of the present invention. The aqueous ink recording sheet 1 includes a base material 2 and an ink image receiving layer 3 provided on the base material 2.

Various materials can be applied to the substrate 2, and an appropriate material is selected according to the use of the aqueous ink recording sheet 1. In the case of the recording sheet 1 for a water-permeable ink for light transmission such as for OHP, a resin film having excellent transparency and flexibility is preferably used as the base material 2.
Examples of such a resin include polyethylene terephthalate, polyvinyl chloride, polypropylene, polycarbonate, polystyrene, polymethyl methacrylate, cellulose acetate, and celluloid. Further, in the case of a recording sheet 1 for water-based ink for ordinary recording, the base material 2
An opaque film is used. Examples of such a base material 2 include a paper material, synthetic paper, a synthetic resin film subjected to opacity treatment, and the like. The thickness of the substrate 2 is
Although it depends on the material and the use of the recording sheet 1 for water-based ink, it generally ranges from 12 micrometers to 100 micrometers.
Those having about 0 micrometers are used.

The ink image receiving layer 3 contains a urethane resin as a main component. This urethane-based resin has excellent pigment fixability as compared with a water-soluble resin or a highly water-absorbing resin.
Therefore, bleeding of the pigment-based ink can be suppressed without adding a filler.

Since the filler is not blended in the ink image receiving layer 3, the light passing through the ink image receiving layer 3 is not blocked. Accordingly, in the case of a transparent aqueous ink recording sheet 1 for OHP or the like, its light transmittance can be increased, and an OHP image can be brightened. Further, in the case of the recording sheet 1 for a normal aqueous ink for recording, the color tone of the base material 2 is easily reflected, and a vivid color tone in which turbidity is suppressed can be obtained. Therefore, for example, when the base material 2 is white paper, the whiteness of the aqueous ink recording sheet 1 can be improved.

Since no filler is blended in the ink image receiving layer 3, its surface is flat. Therefore, the glossiness of the aqueous ink recording sheet 1 can be enhanced.

Since the water-based ink recording sheet 1 uses a urethane resin for the ink image receiving layer 3, it is not necessary to mix a filler as described above, but the light transmittance of the ink image receiving layer 3 can be significantly reduced. A small amount of a filler may be blended within a range that does not lower the viscosity to further improve the bleeding prevention effect of the pigment-based ink. As the filler used, for example, silica,
Colloidal silica, clay, talc, silicon earth, calcium carbonate, aluminum silicate, alumina, zinc oxide,
Known fillers such as synthetic zeolite, calcium sulfate and the like can be mentioned. When a filler is used in combination, it is preferable to reduce the particle size of the filler within a range that does not make handling difficult, because the glossiness of the surface is maintained. A preferred filler has a particle diameter of 0.1 to 50 micrometers.

The ink image receiving layer 3 contains a cationic surfactant. Thereby, the wettability of the additive solvent (water, nonvolatile solvent, etc.) contained in the ink of each color is made uniform, and the ink image receiving layer 3 absorbs the ink of each color in a well-balanced manner. Accordingly, the color developability of the aqueous ink recording sheet 1 is improved. The amount of the cationic surfactant is preferably 0.1 to 90 parts by weight, particularly preferably 10 to 80 parts by weight, based on 100 parts by weight of the urethane resin. If the amount is less than the above range, the balance of the ink absorbency of each color may be lost.
Conversely, if the amount exceeds the above range, the properties of the cationic surfactant will be exhibited, and the ink absorbency may be deteriorated.

In the ink image receiving layer 3, in addition to the urethane resin and the cationic surfactant, water, an organic solvent, a water-soluble resin, a highly water-absorbing resin, a film-forming auxiliary, a plasticizer, a thickener ,
A pH adjuster, an antifoaming agent, a fungicide, a preservative, and the like are appropriately blended.

The ink image receiving layer 3 is formed by coating a resin composition containing a urethane resin as a main component on the substrate 2 and drying the resin composition. Various known methods can be used for coating the resin composition, and for example, a bar coater, a roll coater, a blade coater, a kiss coater, or the like can be used. The amount of coating of the resin composition depends on its composition and the recording sheet
1 g / m ² or more in terms of solid content, depending on the use of
200 g / m ² or less is preferable, 10 g / m ² or more 30 g /
m ² or less is particularly preferred. If the coating amount is less than the above range, the ink absorbency may be poor and the image may bleed. Conversely, if the coating amount exceeds the above range, it may be difficult to dry the resin composition to form a film, or a so-called curl phenomenon may occur.

The structure of the recording sheet 1 for water-based ink is not limited to the one illustrated in FIG. 1. For example, another layer may be provided between the substrate 2 and the ink receiving layer 3, Various changes can be made, such as applying another coating to the underside.

[0021]

EXAMPLES The present invention will be described below with reference to examples, but it should be understood that the present invention should not be construed as being limited based on the description of the examples.

[Examples 1 and 2] Modified urethane resin (trade name "IJ-" manufactured by Dainippon Ink and Chemicals, Inc.)
2)) 100 parts by weight of a cationic surfactant (trade name “AC-13” manufactured by Shin-Nakamura Chemical Co., Ltd.) 13.5
Parts by weight and 50 parts by weight of distilled water were mixed and stirred to obtain a resin composition. On the other hand, as a substrate, a transparent film made of polyethylene terephthalate having a thickness of 100 micrometers (trade name "T-600" manufactured by Diafoil Hoechst Co., Ltd.)
E "). This film was coated with the above resin composition using a roll coater. The coating amount at this time was 20 g / m ² in terms of solid content.
This was dried for 5 minutes at 120 ° C.
Thus, a recording sheet for aqueous ink was obtained.

As a substrate, a white film made of polyethylene terephthalate (trade name “D” manufactured by ICI Japan Co., Ltd.) is used in place of the above transparent film.
A recording sheet for aqueous ink of Example 2 was obtained in the same manner as in Example 1 except for using -534 ").

Comparative Examples 1 and 3 Polyvinyl alcohol (trade name "PVA-117" manufactured by Kuraray Co., Ltd.) 10
Comparative Example 1 was prepared in the same manner as in Example 1 except that a resin composition in which 30 parts by weight of silica (trade name “Sylysia 450” manufactured by Fuji Silysia Chemical Ltd.) was used as a filler was added to 0 part by weight. Thus, a recording sheet for aqueous ink was obtained.

The aqueous ink of Comparative Example 3 was prepared in the same manner as in Comparative Example 1 except that a white film made of polyethylene terephthalate (the above-mentioned trade name "D-534") was used as the substrate instead of the transparent film. A recording sheet was obtained.

Comparative Examples 2 and 4 A recording sheet for an aqueous ink of Comparative Example 2 was obtained in the same manner as in Comparative Example 1 except that silica was not added to the resin composition.

The aqueous ink of Comparative Example 4 was prepared in the same manner as in Comparative Example 2 except that a white film made of polyethylene terephthalate (the above-mentioned trade name "D-534") was used as the substrate instead of the transparent film. A recording sheet was obtained.

[Evaluation of each aqueous ink recording sheet] [Evaluation of bleeding degree of pigment-based ink] One aqueous ink recording sheet of each of Examples and Comparative Examples was prepared. to this,
Using an ink-jet printer (trade name “NOVA JET II” manufactured by ENCAD), using a pigment-based yellow ink, magenta ink, cyan ink and black ink (trade name “GO” manufactured by ENCAD), A rectangle was printed. Then, the degree of bleeding at the periphery of these rectangles was visually observed. The magnitude of the bleeding degree is shown in Table 1 below.

[Evaluation of Glossiness] One recording sheet for aqueous ink of each of Examples and Comparative Examples was prepared, and the glossiness of the surface of the ink receiving layer was visually observed. The result is shown in Table 1 below.
Is shown in

[Measurement of Haze] The recording sheets for aqueous inks of Example 1, Comparative Examples 1 and 2 were prepared, and a haze meter (a direct-reading haze computer manufactured by Suga Test Instruments Co., Ltd.) was used.
The haze was measured at. The results are shown in Table 1 below.

[Measurement of Whiteness] The recording sheets for aqueous inks of Example 2, Comparative Examples 3 and 4 were prepared, and the whiteness was measured using a color difference meter (multi-light source spectrophotometer manufactured by Suga Test Instruments Co., Ltd.). The degree was measured. The results are shown in Table 1 below.

[0032]

[Table 1]

In Table 1, the recording sheet for water-based ink of Example 1 has smaller haze and gloss than the recording sheet for water-based ink of Comparative Example 1, and has more blur than the recording sheet for water-based ink of Comparative Example 2. small. This indicates that the recording sheet for aqueous ink of Example 1 is excellent in all of light transmittance, glossiness and prevention of bleeding of pigment ink.

In Table 1, the recording sheet for aqueous ink of Example 2 has higher whiteness and excellent gloss than the recording sheet for aqueous ink of Comparative Example 3, and the recording sheet for aqueous ink of Comparative Example 4 Less bleeding. This shows that the recording sheet for aqueous ink of Example 2 is excellent in all of whiteness, glossiness and prevention of bleeding of pigment ink.

From the above experimental results, the superiority of the aqueous ink recording sheet according to the present invention was proved. In these experiments, the evaluation was performed using an inkjet printer. However, the recording sheet for an aqueous ink of the present invention, which can suppress the bleeding of the pigment ink without blending a filler, is not limited to the inkjet recording sheet, but is also a plotter. It can be used for various uses such as recording paper for water and recording paper for water-based pens.

[0036]

As described above, according to the present invention,
A recording sheet for an aqueous ink can be provided in which the ink image-receiving layer has a high light transmittance, is glossy, and easily fixes the pigment, so that the bleeding of the pigment-based ink is small.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a recording sheet for aqueous ink according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a conventional aqueous ink recording sheet.

[Explanation of symbols]

 1, 11: aqueous ink recording sheet 2, 12, base material 3, 13: ink image receiving layer

Claims (3)

[Claims] 1. A recording sheet for water-based ink, wherein an ink image-receiving layer containing a urethane resin as a main component is formed on a base material. 2. The recording sheet for an aqueous ink according to claim 1, wherein a cationic surfactant is blended in the ink image receiving layer. 3. The compounding amount of the cationic surfactant is:
The recording sheet for an aqueous ink according to claim 2, wherein the amount is from 0.1 to 90 parts by weight based on 100 parts by weight of the urethane resin.