JP2000247014A - Aqueous ink recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture an aqueous ink recording material of superior ink fixing properties and resistance to water of an ink acceptive layer, and with the short ink absorption time and good transparency even in the case the ink providing amount per unit area is large or in the case either one of an aqueous dye ink or an aqueous pigment ink is used. SOLUTION: An ink acceptive layer is formed on a substrate of a recording material, and the ink acceptive layer is composed of a polyvinyl acetal resin as a main component prepared by using an aromatic aldehyde and converting a polyvinyl alcohol into an acetal. Also the recording material contains a water- soluble acrylic resin, a water-soluble epoxy compound, and fine particles comprising at least one selected from a group consisting of silicic acid, silica, kaolin, clay, alumina, calcium carbonate, zeolite, titanium oxide, talc and a globular polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording material for water-based ink, and more particularly to a recording material for water-based ink, which, when printed with a water-based dye ink or water-based pigment ink in order to achieve full-color printing, is sharp and water-resistant. The present invention relates to a recording material for aqueous ink which can form an excellent image.

[0002]

2. Description of the Related Art In recent years, an ink jet recording system has become widespread as a system for outputting characters and images. Printers and plotters used for inkjet recording are
That noise is low, running cost and equipment price can be reduced, and multi-coloring is possible,
In addition, there is an advantage that a clear image can be easily obtained by miniaturization of the dot pattern.

The following characteristics are required for a recording material used in an ink jet recording system. (A) It has excellent ink absorbency, and can quickly absorb the ink dots adhered to the recording material into the recording material.
In particular, in the case of the color ink jet recording method, since two or more ink dots often overlap at one point on the surface of the recording material, the amount of ink used per unit area increases. Therefore, in the case of the color ink jet recording method, it is strongly required that the ink dots can be more quickly absorbed inside the recording material than in the case of the single color ink jet recording method.

In particular, in an inkjet printer for wide format of A0 size or more, the amount of ink per unit area is set to be very large.
Higher ink absorption is required.

(B) Spreading of ink dots on a recording material can be suppressed. By suppressing the spread of the ink dots, it is possible to eliminate the connection between the ink dots and increase the resolution. Further, it is possible to increase the color density of a recorded matter such as an image and a print. Further, in the case of the color ink jet recording method, by suppressing the spread of the ink dots, it is possible to suppress the decrease in the color saturation caused by the color mixture generated by the connection of two or more ink dots having different colors. Therefore, it is required to further surely suppress the spread of the ink dots.

[0006] In addition to the basic characteristics (a) and (b) described above, the following characteristics (c) to (f) are required for recording materials used in the ink jet recording system. (C) The ink receiving layer of the recording material is transparent. In particular,
When a sheet for an overhead projector (OHP) is formed using a recording material of an ink jet recording system, the ink receiving layer is required to be transparent. Usually, the OHP sheet is made of polyethylene terephthalate (P
(ET) film or the like. However, PET films themselves do not absorb water-based inks. Therefore, PET film as a support,
By providing an ink receiving layer thereon, absorption of aqueous ink is achieved. However, if the ink receiving layer is opaque, light is blocked or scattered, and O
It cannot be used as a sheet for HP.

(D) The recording material has excellent water resistance. If the water resistance of the recording material is not sufficient, if the water adheres or is immersed in water, the ink receiving layer may peel off and the image may disappear.

(E) The printed surface can be dried in a shorter time. By increasing the water resistance of the recording material, even if the recording material is immersed in water, the ink receiving layer does not peel off and the image does not disappear. However, increasing the water resistance increases the time for the aqueous ink to be absorbed into the ink receiving layer. As a result, if the hand touches the printing section before the printed ink dries, there occurs a problem that the ink is transferred to the hand.

(F) Clear printing is possible regardless of the type of aqueous dye ink or aqueous pigment ink. In the case of performing black printing, an aqueous pigment ink is used in some printers and plotters in order to give a deeper color. Aqueous pigment inks are also used in applications used for signs requiring weather resistance.

However, unlike water-based dye inks, water-based pigment inks have an ink receiving layer that receives a normal water-based dye ink, and the ink undergoes dispersion destruction on the surface of the ink receiving layer before the ink is absorbed or dried after printing. This caused problems such as cracks and repelling after printing.

Conventionally, as a recording material for aqueous ink, for example, JP-A-55-146786 and JP-A-59-1
As disclosed in U.S. Pat. No. 74,381, an ink receiving layer formed of a water-soluble resin such as polyvinyl alcohol or polyvinyl pyrrolidone on a support such as a plastic film, paper, or a glass plate is known. .

However, in these recording materials for aqueous inks, although the absorbability and fixability of the aqueous dye ink are good, the fixability of the aqueous pigment ink is insufficient, and the water resistance of the ink receiving layer is insufficient. Or not.

Further, for example, Japanese Patent Application Laid-Open No. Sho 57-102391
Japanese Patent Application Publication No. JP-A-2002-133873 discloses an ink jet recording material having an ink receiving layer formed by mixing a hydrophilic polymer and a lipophilic polymer in order to balance the absorbability and water resistance of the aqueous ink. .

However, in the recording material for the ink jet recording system described in the prior art, the compatibility of the hydrophilic polymer and the lipophilic polymer is not good, so that the transparency of the ink receiving layer is not sufficient. It could not be used as an OHP sheet, and the fixability of the aqueous pigment ink was not sufficient.

Further, for example, Japanese Patent Publication No. Hei 5-23597 discloses an ink jet recording material using a water-resistant polyvinyl acetal resin such as polyvinyl phenylacetoacetal as an ink receiving layer. However, in the recording material described in this prior art, although the absorbability and fixability of the aqueous dye ink were good, the fixability of the aqueous pigment ink was insufficient.

In general, if the water resistance of the ink receiving layer is too high, the aqueous dye ink is not completely absorbed into the ink receiving layer but dries on the surface of the ink receiving layer, and as a result, bleeding and ink agglomeration occur. There have been problems that a phenomenon called beading occurs, the water resistance of the printed portion is poor, and particularly when the ink on the surface of the receiving layer is black ink, the color changes to brown over time. Therefore, none of the conventional recording materials described above has sufficient performance, and further improvement in performance is strongly demanded.

[0017]

SUMMARY OF THE INVENTION An object of the present invention is to provide a wide format ink jet printer of A0 size or more, in which a large amount of ink is applied per unit area, using either an aqueous dye ink or an aqueous pigment ink. An object of the present invention is to provide a recording material for an aqueous ink which is excellent in ink fixing property and water resistance of an ink receiving layer, has a short ink absorption time, and has good transparency even when printing.

[0018]

The present invention relates to a recording material for water-based ink having an ink-receiving layer provided on a support, wherein the ink-receiving layer is formed by acetalizing polyvinyl alcohol with an aromatic aldehyde. Polyvinyl acetal resin obtained by the conversion, water-soluble acrylic resin, water-soluble epoxy compound, silicic acid, silica,
It is characterized by containing fine particles of at least one selected from the group consisting of kaolin, clay, alumina, calcium carbonate, zeolite, titanium oxide, talc and spherical polymers.

In the recording material for aqueous ink according to the present invention, the content of the water-soluble acrylic resin is preferably 10 to 30 parts by weight based on 100 parts by weight of the polyvinyl acetal resin.

Preferably, the content of the water-soluble epoxy compound is 15 to 40 parts by weight based on 100 parts by weight of the polyvinyl acetal resin. As the polyvinyl acetal resin, one having a degree of acetalization of 6 to 15 mol% is preferably used.

Hereinafter, the present invention will be described in detail. In the recording material for aqueous ink according to the present invention, the ink receiving layer is provided on the support.

The material constituting the support is not particularly limited. For example, polyethylene terephthalate (P
ET), films or sheets made of synthetic resins such as polystyrene, polyvinyl chloride, polymethyl methacrylate, cellulose acetate, polyethylene, polypropylene, nylon, polycarbonate, ABS; woven fabric, nonwoven fabric, fiber, cloth, paper, synthetic paper, glass A plate, a metal plate, wood, or the like can be used.

The ink receiving layer contains a polyvinyl acetal resin as a main component, and the polyvinyl acetal resin comprises:
It is composed of a resin composition containing a water-soluble acrylic resin, a water-soluble epoxy compound, and fine particles.

The polyvinyl acetal resin is obtained by reacting polyvinyl alcohol with an aldehyde using an acid catalyst to form acetal. The polymerization degree of the polyvinyl alcohol used here is 200 to 350.
A range of 0 is preferred. If the degree of polymerization is less than 200, it may be difficult to synthesize polyvinyl alcohol,
If it exceeds 0, the viscosity of the aqueous solution becomes too high, so that an acetalization reaction hardly occurs.

The degree of saponification of polyvinyl alcohol is 75
~ 99.8 mol% is preferred. If the saponification degree is less than 75 mol%, the solubility in water may be insufficient, and 9
If it exceeds 9.8 mol%, the solubility in water may still be insufficient.

Further, two or more kinds of polyvinyl alcohols having different degrees of polymerization may be mixed and used. In this case, it is preferable to select and use two or more kinds of polyvinyl alcohols whose apparent degree of polymerization is within the above range.

The polyvinyl acetal resin is obtained by acetalizing polyvinyl alcohol with an aromatic aldehyde. The aromatic aldehyde is not particularly limited, and examples thereof include benzaldehyde and 2-
Alkyl-substituted benzaldehydes such as methylbenzaldehyde, 3-methylbenzaldehyde and 4-methylbenzaldehyde; halogen-substituted benzaldehyde;
Aromatic aldehyde substituted with a hydroxy group such as hydroxybenzaldehyde and m-hydroxybenzaldehyde; aromatic aldehyde having a substituent such as an alkoxy group, amino group, cyano group; phenyl substitution such as phenylacetaldehyde and β-phenylpropionaldehyde Alkyl aldehydes and the like can be mentioned.

The aromatic aldehyde may have a large number of hydroxyl groups and other polar groups in order to increase the hydrophilicity. Generally, when the number of hydroxyl groups and other polar groups is increased, hydrophilicity is greatly changed. By controlling the degree of acetalization in the range of 6 to 15 mol%, ink is not greatly changed. The water resistance of the entire receiving layer can be increased.

The method for acetalization is not particularly limited, and conventionally known methods such as a dissolution method, a precipitation method, and a homogeneous method can be used. The acid catalyst is not particularly limited, and examples thereof include inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid; and organic acids such as acetic acid and p-toluenesulfonic acid.

The above polyvinyl alcohol can be obtained by, for example, saponifying polyvinyl acetate. Therefore, instead of using polyvinyl alcohol,
Saponification and acetalization may be performed in parallel using polyvinyl acetate.

The polyvinyl acetal resin preferably has a degree of acetalization with an aromatic aldehyde in the range of 6 to 15 mol%. If the degree of acetalization is less than 6 mol%, the water resistance of the recording material may decrease,
If it exceeds 15 mol%, the water resistance becomes too high, and the absorptivity of the water-based dye ink decreases during printing, causing bleeding in the image or long enough for the ink to be completely absorbed into the ink receiving layer. May require time.

The water-soluble acrylic resin is also
It is not particularly limited, and is obtained by polymerizing at least one selected from the group consisting of acrylic acid, acrylate, methacrylic acid, and methacrylate, or obtained by copolymerizing these with another acrylic resin. The one used is used.

The acrylate and methacrylate are not particularly limited, but generally include those in which Li, Na, K, Mg, Ca, Al, etc. are added to the terminal of the carboxylic acid.

[0034] The acrylic resin to be copolymerized is not particularly limited, but acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate and 2-ethylhexyl acrylate; isobonyl acrylate, acrylic acid Dimethylaminoethyl ester, isobutyl acrylate, cetyl acrylate, acrylic acid 4
-Hydroxybutyl, t-butyl acrylate, 2-methoxyethyl acrylate, 3-methoxybutyl acrylate, lauryl acrylate, ethyl 3-dimethyl acrylate, ethoxydiethylene glycol acrylate, n
-Stearyl acrylate, tetrahydrofurfuryl acrylate, 2-hydroxyethyl acrylate, 2-
Hydroxypropyl acrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate,
Octyl methacrylate, i-decyl methacrylate, lauryl methacrylate, lauryl decyl methacrylate,
Examples include methacrylates such as tridecyl methacrylate, cetyl-stearyl methacrylate, cyclohexyl methacrylate, and benzyl methacrylate.

The water-soluble acrylic acid monomers may be used alone or in combination of two or more. The weight average molecular weight of the water-soluble acrylic resin is not particularly limited, but is preferably from 2,000 to 200,000. If the weight average molecular weight is less than 2,000, the strength of the ink receiving layer may be low,
If it exceeds 000, its viscosity becomes too high when it is made into an aqueous solution, and it may be difficult to mix uniformly.

The amount of the water-soluble acrylic resin is as follows:
For 100 parts by weight of the polyvinyl acetal resin,
10 to 30 parts by weight are preferred. If the amount is less than 10 parts by weight, the drying time of the aqueous ink is long and drying may be insufficient. If the amount exceeds 30 parts by weight, the hydrophilicity becomes too strong and the water resistance of the ink receiving layer is insufficient. Or bleeding may occur.

The water-soluble epoxy compound is a water-soluble epoxy compound having two or more epoxy groups, for example, 1,4-butanediol glycidyl ether, bisphenol A epichlorohydrin epoxy resin, trimethylol Propane polyglycidyl ether,
Neopentyl glycol diglycidyl ether, glycerol polyglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether,
Examples include diglycerol polyglycidyl ether, propylene glycol diglycidyl, polypropylene glycol diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, sorbitol polyglycidyl ether, and trimethylolpropane polyglycidyl ether.

The amount of the water-soluble epoxy compound is preferably 15 to 40 parts by weight based on 100 parts by weight of the polyvinyl acetal resin. If the amount is less than 15 parts by weight, the fixability of the aqueous pigment ink may be insufficient, and if it exceeds 40 parts by weight,
The reaction between the water-soluble acrylic resin and the water-soluble epoxy compound progresses too much to increase the water resistance, which may cause the aqueous dye ink to be repelled on the surface of the receiving layer.

As the fine particles, at least one selected from the group consisting of silicic acid, silica, kaolin, clay, alumina, calcium carbonate, zeolite, titanium oxide, talc and spherical polymers is used.

The spherical polymer is not particularly restricted but includes, for example, polymethyl methacrylate, methyl methacrylate-ethyl methacrylate copolymer, polystyrene, polymethacrylate, polyacrylate, sodium polyacrylate and the like. Can be mentioned.

The average particle size of the fine particles is preferably in the range of 5 to 25 μm. When the particle size is less than 5 μm, the effect of improving the anti-blocking property at the time of moisture absorption due to the addition of the fine particles cannot be sufficiently obtained. When the particle size exceeds 25 μm, the particle size of the fine particles is large, so that the transparency and the gloss are reduced. Sometimes.

The fine particles are used in an amount of 0.1 to 1.0 with respect to 100 parts by weight of the total solid content of the polyvinyl acetal resin, the water-soluble acrylic resin and the water-soluble epoxy compound.
It is preferable to add in the range of parts by weight. If the amount is less than 0.1 part by weight, the effect of improving the anti-blocking property during moisture absorption due to the addition of the fine particles may not be sufficiently obtained,
If it exceeds 1.0 part by weight, transparency and glossiness may be reduced.

In the present invention, various additives may be added to the resin composition constituting the ink receiving layer as long as the object of the present invention is not impaired. Examples of the additives include, for example, glycerin, ethylene glycol, polyethylene glycol, a surfactant, an ultraviolet absorber, a pigment dispersant, an antifoaming agent, a preservative, a pH adjuster, and an antiblocking agent in order to enhance the ink adsorption performance. And the like.

In the recording material for aqueous ink according to the present invention, the ink receiving layer is formed by applying the resin composition on the support, forming the resin composition, and then drying.

With respect to the method of preparing the above resin composition, the above-mentioned water-soluble acrylic resin, water-soluble epoxy compound and fine particles are added to a polyvinyl acetal resin.
What is necessary is just to knead sufficiently.

The method of applying the resin composition is not particularly limited, and a known method such as a roll coater method or a blade coater method can be used. The coating amount of the ink receiving layer after drying is preferably in the range of 0.5 to 25 g / m ² . When the coating amount is less than 0.5 g / m ² , the ink absorption amount is not sufficient and bleeding may occur. When the coating amount is more than 25 g / m ² , the hygroscopicity in a high humidity atmosphere increases. In some cases, the water resistance may be reduced, or a curl phenomenon in which the recording material is bent in a tubular shape may occur.

The drying temperature of the resin composition is 8
The temperature is preferably set to 0 to 150 ° C. Below 80 ° C,
Since the water-soluble acrylic acid-based resin and the water-soluble epoxy-based compound do not easily react with each other, the water resistance may be degraded.
If the temperature is higher than ° C, the ink receiving layer may be deteriorated by heat, or the water-soluble acrylic resin and the water-soluble epoxy compound may react excessively to lower the ink absorbency.

The drying time of the resin composition layer is desirably 1 to 10 minutes. If the drying time is less than 1 minute, the ink receiving layer itself may be insufficiently dried, and the water-soluble acrylic resin and the water-soluble epoxy compound are unlikely to react with each other. is there. Drying time is 10
If the amount exceeds the limit, the reaction between the water-soluble acrylic resin and the water-soluble epoxy compound proceeds excessively, and the ink absorbency may be reduced.

In order to enhance the adhesion between the support and the ink receiving layer, the surface of the support may be previously oxidized by corona discharge, or an adhesive resin layer may be provided on the support.
As the aqueous ink used in the recording material for an aqueous ink according to the present invention, any of an aqueous dye ink and an aqueous pigment ink can be used.

The aqueous dye ink is not particularly limited. For example, as disclosed in JP-A-47-12105, water-soluble dyes, water, other water-miscible organic solvents, wetting agents, dyes What consists of a solubilizer, an antifungal agent and the like is used.

The aqueous pigment ink is not particularly limited. For example, as disclosed in JP-A-7-278481, a pigment, water, a water-miscible organic solvent, a wetting agent, a pigment dispersant, a fungicide, What consists of agents etc. is used.

In the recording material for aqueous ink according to the present invention, an ink receiving layer is formed by a resin composition comprising the above-mentioned polyvinyl acetal resin as a main component, and a water-soluble acrylic resin, a water-soluble epoxy compound and the above-mentioned fine particles. With this configuration, clear printing can be obtained even when printing is performed using either the aqueous dye ink or the aqueous pigment ink. In addition, even when printing is performed with a printer having a large amount of ink adhered per unit area, such as when used in an inkjet printer for a wide format of A0 size or more, it contains a water-soluble acrylic resin. As a result, bleeding and beading of the ink hardly occur, and the ink fixing property is excellent.

When the water-soluble acrylic resin is contained in a proportion of 10 to 30 parts by weight with respect to 100 parts by weight of the polyvinyl acetal resin, the drying time of the aqueous ink can be shortened and the ink can be dried. The water resistance of the receiving layer can be increased, and the occurrence of bleeding can be more effectively suppressed.

When the water-soluble epoxy compound is blended in a proportion of 15 to 40 parts by weight with respect to 100 parts by weight of the polyvinyl acetal resin, the fixability of the water-based pigment ink can be improved, and a suitable water resistance can be obtained. And can effectively suppress the repelling of the aqueous dye ink on the surface of the ink receiving layer.

Further, as a polyvinyl acetal resin,
When the one having an acetalization degree of 6 to 15 mol% is used, the absorbability of the aqueous dye ink or the aqueous pigment ink can be further enhanced, and the water resistance of the ink receiving layer can be further enhanced.

[0056]

Hereinafter, the present invention will be described in more detail by giving specific examples of the present invention.

Example 1 Preparation of Polyvinyl Acetal Resin (A) 200 g of polyvinyl alcohol having a polymerization degree of 2,000 and a saponification degree of 88 mol% was added to 1600 g of pure water, and the mixture was stirred at a temperature of 90 ° C. for 2 hours and dissolved. . The obtained solution was cooled to 45 ° C., and 50 g of hydrochloric acid having a concentration of 35% by weight was added.
Cooled to 25 ° C., and added with 27 g of benzaldehyde.
For 4 hours. In this case, the final degree of acetalization was 9 mol%.

Next, the temperature of the solution was cooled to 20 ° C., and while stirring, a 10% by weight aqueous solution of sodium hydroxide 19 was added.
2 g was added for neutralization to obtain a sponge-like precipitate. The resulting spongy precipitate was washed with water to remove neutralized salts and unreacted aldehydes, and dried to obtain a powdery polyvinyl acetal resin (A).

Preparation of Recording Material for Aqueous Ink The polyvinyl acetal resin (A) was dissolved in a mixed solvent containing water and isopropyl alcohol at a weight ratio of 6: 4 to prepare a polyvinyl acetal resin solution. Next, the polyvinyl acetal resin solution was added to the following Table 1
Was added in an amount of 20 parts by weight to 100 parts by weight of the polyvinyl acetal resin (A), and then the water-soluble epoxy compound (B) shown in Table 1 below was added. C) was added in an amount of 30 parts by weight based on 100 parts by weight of the polyvinyl acetal (A). Further, the fine particles shown in Table 1 below were mixed with the polyvinyl acetal resin (A) and the water-soluble acrylic resin (B). ) And water soluble epoxy compound (C)
0.4 parts by weight was added to 0 parts by weight and mixed. Thereafter, the obtained resin mixture was applied on a PET film having a thickness of 100 μm, and dried at 120 ° C. for 5 minutes.
A recording material for an aqueous ink having an ink receiving layer having a weight after drying of 12 g / m ² was obtained.

Example 2 The procedure of Example 1 was repeated, except that polyvinyl alcohol having a degree of polymerization and a degree of saponification shown in Table 1 below was used, and the degree of acetalization with benzaldehyde was 10 mol%. A polyvinyl acetal resin (A) was obtained.

The obtained polyvinyl acetal resin (A)
Was dissolved in the same manner as in Example 1, and a water-soluble acrylic resin (B) and a water-soluble epoxy compound (C) shown in Table 1 below were added to a polyvinyl acetal resin solution, respectively.
Aqueous ink recording was carried out in the same manner as in Example 1 except that 15 parts by weight and 20 parts by weight were added, and the fine particles shown in Table 1 were added in the same mixing ratio as in Example 1. Wood was obtained.

Example 3 Example 1 was repeated except that polyvinyl alcohol having the degree of polymerization and saponification shown in Table 1 below was used, and the degree of acetalization with benzaldehyde was 12 mol%. In the same manner as in the above, a polyvinyl acetal resin (A) was obtained.

The polyvinyl acetal resin (A) obtained as described above was dissolved in the same manner as in Example 1 to obtain a polyvinyl acetal resin solution. To this polyvinyl acetal resin solution, 25 parts by weight of a water-soluble acrylic resin (B) and 35 parts by weight of a water-soluble epoxy compound (C) shown in Table 1 below were added. A recording material for an aqueous ink was obtained in the same manner as in Example 1, except that the fine particles shown were added at the same compounding ratio as in Example 1.

Example 4 Polyvinyl alcohol having a polymerization degree and a saponification degree shown in Table 1 below was used, and the degree of acetalization with benzaldehyde was 7 mol%.
A polyvinyl acetal resin (A) was obtained in the same manner as in Example 1, except that

The polyvinyl acetal resin (A) thus obtained was dissolved in the same manner as in Example 1 to obtain a polyvinyl acetal resin solution. To this polyvinyl acetal resin solution, 20 parts by weight of a water-soluble acrylic resin (B) and 25 parts by weight of a water-soluble epoxy compound (C) shown in Table 1 below were added. A recording material for an aqueous ink was obtained in the same manner as in Example 1, except that the fine particles shown were added at the same compounding ratio as in Example 1.

Example 5 Polyvinyl alcohol having the degree of polymerization and the degree of saponification shown in Table 1 below was used, and the degree of acetalization with benzaldehyde was 8 mol%.
A polyvinyl acetal resin (A) was obtained in the same manner as in Example 1, except that

The polyvinyl acetal resin (A) thus obtained was dissolved in the same manner as in Example 1 to obtain a polyvinyl acetal resin solution. To this polyvinyl acetal resin solution, 17 parts by weight of the water-soluble acrylic resin (B) and 30 parts by weight of the water-soluble epoxy compound (C) shown in Table 1 below were added. A recording material for an aqueous ink was obtained in the same manner as in Example 1, except that the fine particles shown were added at the same compounding ratio as in Example 1.

Example 6 Example 1 was repeated except that polyvinyl alcohol having the degree of polymerization and the degree of saponification shown in Table 1 below was used, and the degree of acetalization with benzaldehyde was 14 mol%. In the same manner as in the above, a polyvinyl acetal resin (A) was obtained.

The polyvinyl acetal resin (A) obtained as described above was dissolved in the same manner as in Example 1 to obtain a polyvinyl acetal resin solution. To this polyvinyl acetal resin solution, 20 parts by weight of a water-soluble acrylic resin (B) and 25 parts by weight of a water-soluble epoxy compound (C) shown in Table 1 below were added. A recording material for an aqueous ink was obtained in the same manner as in Example 1, except that the fine particles shown were added at the same compounding ratio as in Example 1.

Example 7 Example 1 was repeated except that polyvinyl alcohol having the degree of polymerization and the degree of saponification shown in Table 1 below was used, and the degree of acetalization with benzaldehyde was 10 mol%. In the same manner as in the above, a polyvinyl acetal resin (A) was obtained.

The polyvinyl acetal resin (A) obtained as described above was dissolved in the same manner as in Example 1 to obtain a polyvinyl acetal resin solution. To this polyvinyl acetal resin solution, 20 parts by weight of the water-soluble acrylic resin (B) and 35 parts by weight of the water-soluble epoxy compound (C) shown in Table 1 below were added. A recording material for an aqueous ink was obtained in the same manner as in Example 1, except that the fine particles shown were added at the same compounding ratio as in Example 1.

Example 8 Polyvinyl alcohol having the polymerization degree and the saponification degree shown in Table 1 below was used, and the acetalization degree with benzaldehyde was 9 mol%.
A polyvinyl acetal resin (A) was obtained in the same manner as in Example 1, except that

The polyvinyl acetal resin (A) obtained as described above was dissolved in the same manner as in Example 1 to obtain a polyvinyl acetal resin solution. To this polyvinyl acetal resin solution, 25 parts by weight of the water-soluble acrylic resin (B) and 30 parts by weight of the water-soluble epoxy compound (C) shown in Table 1 below were added. A recording material for an aqueous ink was obtained in the same manner as in Example 1, except that the fine particles shown were added at the same compounding ratio as in Example 1.

Comparative Example 1 The same as Example 1 except that polyvinyl alcohol having a degree of polymerization and a degree of saponification shown in Table 2 below was used, and the degree of acetalization with benzaldehyde was 3 mol%. Thus, a polyvinyl acetal resin (A) was obtained.

The obtained polyvinyl acetal resin (A)
Was dissolved in the same manner as in Example 1 to obtain a polyvinyl acetal resin solution. Example 1 was repeated except that no fine particles were added to the polyvinyl acetal resin solution.
In the same manner as in the above, a recording material for aqueous ink was obtained.

Comparative Example 2 Same as Example 1 except that polyvinyl alcohol having a degree of polymerization and a degree of saponification shown in Table 2 below was used, and the degree of acetalization with benzaldehyde was 20 mol%. Thus, a polyvinyl acetal resin (A) was obtained.

The obtained polyvinyl acetal resin (A)
Was dissolved in the same manner as in Example 1 to obtain a polyvinyl acetal resin solution. Example 1 was repeated except that no fine particles were added to the polyvinyl acetal resin solution.
In the same manner as in the above, a recording material for aqueous ink was obtained.

Comparative Example 3 A recording material for aqueous ink was prepared in the same manner as in Example 2 except that the water-soluble acrylic resin (B) was not added.

Comparative Example 4 A recording material for aqueous ink was prepared in the same manner as in Example 3 except that the water-soluble acrylic resin (B) was not added.

Comparative Example 5 A recording material for aqueous ink was prepared in the same manner as in Example 4 except that the water-soluble epoxy compound (C) was not added.

Comparative Example 6 A recording material for aqueous ink was prepared in the same manner as in Example 5, except that the water-soluble epoxy compound (C) was not added.

Comparative Example 7 A recording material for aqueous ink was prepared in the same manner as in Example 6, except that no fine particles were added.

Comparative Example 8 A recording material for aqueous ink was produced in the same manner as in Example 7, except that no fine particles were added.

(Evaluation of Examples and Comparative Examples) Example 1
The performance of each of the aqueous ink recording materials obtained in Comparative Examples 1 to 8 and Comparative Examples 1 to 8 was evaluated by the following method. The results are shown in Table 3 below.

(1) Water resistance After the ink receiving layer of 30 × 30 cm square was formed by drying, 24 hours later, the recording material for aqueous ink was immersed in tap water for 60 minutes, and immediately after being lifted up, the ink receiving layer was removed. Was visually observed. The evaluation was made using the following evaluation symbols. ：: The ink receiving layer was not different from that before immersion. Δ: The ink receiving layer swelled and was partially peeled from the support. ×: The ink receiving layer was dissolved and was washed away from the support.

(2) Bleeding A0 size ink receiving layer was solid-printed in a size of 30 × 30 cm using an aqueous dye ink and an aqueous pigment ink, and the formed image portion was printed 24 hours after printing. Was visually observed. Evaluation was made according to the following criteria. A: The size of “bleeding” around the image area was 50 μm or less. ：: The size of “bleeding” around the image portion was more than 50 μm and 100 μm or less. ：: The size of “bleeding” around the image portion was more than 100 μm and not more than 300 μm. ×: The size of “bleeding” around the image portion exceeded 300 μm.

(3) Beading The image area formed by applying a 30 × 30 cm square water-based dye ink on the ink-receiving layer of A0 size using solid dye ink was used for the image area 24 hours after printing. The state was visually observed. Evaluation was made according to the following criteria. ：: There is no beading phenomenon. B: Beading with a granular feeling in which the ink aggregated occurred in a part of the image area. ×: Beading with a granular feeling in which the ink was aggregated occurred over the entire image area.

(4) Surface Condition of the Printed Area The image area formed by solid printing with a 30 × 30 cm square water-based dye ink on an A0 size ink receiving layer was printed 24 hours after printing. The state of the image area was visually observed. Evaluation was made according to the following criteria. ：: No “crack” or “repellent” was observed on the printed surface. Δ: “Crack” or “Repelling” was recognized on a part of the printing surface. ×: “Crack” or “Repelling” was observed on the entire printing surface.

(5) Ink Transfer An image portion formed by solid printing with an aqueous dye ink and an aqueous pigment ink in a size of 30 × 30 cm on an A0 size ink receiving layer was printed 5 minutes after printing. The paper for PPC was pressed against the portion, and the state of transfer of the ink to the paper was visually observed. Evaluation was made according to the following criteria. ：: There was no transfer of the ink to the paper. Δ: Ink was partially transferred to paper. X: Transfer of the ink to the paper was on the entire printing portion.

(6) Transparency The state of the ink receiving layer was visually observed. The transparency was evaluated according to the following criteria. ：: The entire surface was transparent without fogging. Δ: Clouding was observed in a part of the ink receiving layer. ×: Glassy cloudiness was observed on the entire surface.

[0091]

[Table 1]

[0092]

[Table 2]

[0093]

[Table 3]

In Comparative Example 1, the degree of acetalization of the polyvinyl acetal resin was low, so that the water resistance was poor, and "bleeding" and "cracks" occurred in the recording portion with the aqueous pigment ink. Further, since no fine particles were added, ink transfer was observed when the paper was pressed against the printing portion 5 minutes after printing.

In Comparative Example 2, since the degree of acetalization of the polyvinyl acetal resin was high, the water resistance was too good, and “blur” appeared considerably around the image area of the recording area with the aqueous dye ink. It was found that the absorbency was not sufficient. Further, since no fine particles were added, ink transfer was observed when the paper was pressed against the printing portion 5 minutes after printing.

In Comparative Examples 3 and 4, since no water-soluble acrylic resin was blended, "bleeding" or "blur" occurred around the image area in the aqueous dye ink recording area, and paper was printed on the printing area 5 minutes after printing. Ink transfer was observed when pressed.

In Comparative Examples 5 and 6, since no water-soluble epoxy compound was blended, “cracks” and “repelling” occurred in the recording portion of the aqueous pigment ink, and the ink was not pressed when the paper was pressed against the printing portion 5 minutes after printing. A shift was seen. In Comparative Examples 7 and 8, since fine particles were not added to the ink receiving layer, ink transfer was observed when the paper was pressed against the printed portion 5 minutes after printing.

On the other hand, in Examples 1 to 8, since the water-soluble acrylic resin and the water-soluble epoxy compound were blended in the polyvinyl acetal resin, the water-based dye ink and the water-based pigment ink were bleeding and beading. There was no phenomenon of ink transfer and no ink transfer when the paper was pressed against the printed portion after 5 minutes of printing because of the inclusion of fine particles. In addition, the ink absorption time was short, and the transparency was excellent.

[0099]

According to the recording material for aqueous ink according to the present invention,
Since the ink receiving layer is provided on the support, the ink receiving layer contains the specific polyvinyl acetal resin, a water-soluble acrylic resin, a water-soluble epoxy compound, and the specific fine particles. In addition, the ink absorbency, the water resistance of the image and the fixability are effectively improved.

Therefore, when either the aqueous dye ink or the aqueous pigment ink is used,
Even when printing is performed with a wide format printer of A0 size or more, which has a large amount of ink per unit area, a clear image can be obtained.

Further, since the ink receiving layer has water resistance and is excellent in transparency and gloss, it can be used as a recording material for constructing a signboard used indoors or outdoors. Furthermore, since the ink receiving layer has excellent transparency, it can be suitably used for OHP sheets and the like.

Claims (4)

[Claims] 1. A recording material for aqueous ink comprising an ink receiving layer provided on a support, wherein the ink receiving layer is obtained by acetalizing polyvinyl alcohol with an aromatic aldehyde. An acetal resin, a water-soluble acrylic resin, a water-soluble epoxy compound, and at least one selected from the group consisting of silicic acid, silica, kaolin, clay, alumina, calcium carbonate, zeolite, titanium oxide, talc, and a spherical polymer. A recording material for water-based ink, comprising: one kind of fine particles. 2. The content of the water-soluble acrylic resin is from 10 to 3 parts by weight based on 100 parts by weight of the polyvinyl acetal resin.
The aqueous ink recording material according to claim 1, wherein the amount is 0 parts by weight. 3. The content of the water-soluble epoxy compound is 15 to 4 parts by weight based on 100 parts by weight of the polyvinyl acetal resin.
The aqueous ink recording material according to claim 1, wherein the amount is 0 parts by weight. 4. The polyvinyl acetal resin according to claim 1, wherein the degree of acetalization is 6 to 15 mol%.
4. The recording material for aqueous ink according to any one of items 1 to 3.