JP2001010228A - Color developing sheet for pressure-sensitive recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color developing sheet for pressure-sensitive recording which is free from deterioration of coloring density due to a color developing layer and from occurrence of color fogging and has an excellent water resistance. SOLUTION: This color developing sheet for pressure-sensitive recording has a constitution wherein a color developing layer containing a binder and an electron-accepting developer is provided on a substrate 1) or a constitution wherein the color developing layer containing the binder and the electron- accepting developer is provided on the substrate and a protective layer constituted mainly of the binder is provided on the color developing layer. In this case, the binder contains an ethylene-modified polyvinyl alcohol resin. It is desirable that the ethylene modification rate of this ethylene-modified polyvinyl alcohol is 1-20%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a color developing sheet for pressure-sensitive recording, and more particularly to a color developing sheet for pressure-sensitive recording having improved water resistance and printability.

[0002]

2. Description of the Related Art A color-forming layer comprising microcapsules containing an electron-donating color-forming agent (hereinafter sometimes referred to as "color-forming agent") and an electron-accepting color developing agent (hereinafter referred to as a "color-developing agent"). Pressure) by applying pressure to the microcapsules to break the microcapsules and react the color former with the color former to form a color image. Recording sheets have been known for a long time and are widely used.

[0003] As an embodiment of such a pressure-sensitive recording sheet,
Broadly speaking, the color-forming layer and the color-developing layer are formed on separate support surfaces, and the color-forming layer and the color-developing layer are used in contact with each other. Provided with a self-coloring layer containing microcapsules and a color developing agent,
There is a so-called self-coloring type pressure-sensitive recording sheet (or press type paper, self-contained paper).

[0004] When making a plurality of copies, the upper sheet is provided with a coloring layer on one side of the support, and the inner sheet is provided with a coloring layer on one side of the support and a developing layer on the opposite side. In some cases, the support is used in combination with a lower sheet provided with a color developing layer on one side of the support.

[0005] The pressure-sensitive recording sheet is used not only for copying characters and the like, but also when transporting precision equipment and artworks, for example, by directly attaching them to them or by attaching them to a packaging container, and during transportation. To record whether an article has hit another object (a color image is generated at the point where the object hit)
Used as a pressure measurement sensor.

Conventionally, a water-soluble or hydrophilic polymer compound such as polyvinyl alcohol or starch has been used as a binder for a color developing layer of a color developing sheet for pressure-sensitive recording. It has poor water resistance, and if water adheres to the color developing layer and is rubbed, this layer is easily peeled off.
As described above, the range of use of the pressure-sensitive recording color developing sheet is expanded, and the chance of being used outdoors increases, so that the pressure-sensitive recording sheet is often wetted by water, etc. Sex has become an important issue.

Conventionally, as a means for imparting water resistance to a coating film, a synthetic rubber latex such as styrene-butadiene-rubber latex is solely mixed, but in order to impart sufficient water resistance, It is necessary to use a large amount of these synthetic rubber latexes.If a large amount of the synthetic rubber latex is added to the color developing layer of the pressure-sensitive recording sheet, the color density may decrease or the coating solution for forming the color developing layer may aggregate. There was a problem such as doing.

Japanese Patent Laid-Open Publication No. Sho 52-68513 discloses a recording sheet in which a protective layer of a resin such as a polyolefin resin extruded on a self-coloring layer of a self-coloring type pressure-sensitive recording sheet is formed. Have been. This recording sheet has the characteristics that it has no color fogging, has no inferiority in color development under pressure, and has excellent water resistance, stain resistance and the like, but has a problem that the production cost is high.

The self-coloring type pressure-sensitive recording sheet prints colored ink in the same manner as a normal self-coloring type pressure-sensitive recording sheet to obtain a desired image. As a method to print colored ink,
Flexo / gravure, letterpress, offset printing, etc. are commonly used, but offset printing is generally used because of the ease of plate making, delicate color tone and ink deposition, and the fact that it is relatively inexpensive even with a small number of copies. You. The offset printing method uses a lithographic plate having a non-image portion having hydrophilicity and an image portion having lipophilicity, and using a dampening solution called etch water for the hydrophilic portion. Therefore, of course, dampening water also transfers and adheres to the coated paper on which the colored ink is printed by the printing pressure. In this case, an important characteristic item required for the coated paper is a surface strength (so-called pick strength) with respect to the coloring ink and the fountain solution.

The surface strength of coated paper can be roughly classified into dry pick strength and wet topic strength. For example, if the dry pick strength is low, the coloring ink contains a sticky substance, and the pressure of printing pressure is applied, causing the coating layer to peel off, transferring to a blanket, laminating, etc. Clear images cannot be obtained, such as transfer to paper. On the other hand, if the wet topical strength is weak, the dampening solution adhering portion is peeled off by the coating pressure due to the printing pressure, and there is the same trouble as described above.

As a solution to these problems, in general, the dry pick strength can be almost controlled by the amount of a water-soluble or hydrophobic polymer binder, and the wet topic strength can be controlled by a hydrophobic polymer binder. This can be achieved by adding a styrene-butadiene latex emulsion or a known water-resistant agent. However, in the case of a self-coloring type pressure-sensitive recording sheet in which a color former is microencapsulated, the use of a large amount of latex emulsion as a binder can certainly achieve an effect of improving the wet topic strength, but the key color density is important. And the hue becomes pale.

[0012]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a pressure-sensitive recording color developing sheet having excellent water resistance and printability without causing a reduction in color density or generation of color fogging in a color developing layer. It is in.

[0013]

Means for Solving the Problems As a result of the inventor's intensive search for the above-mentioned problems, the present inventors have found that the use of an ethylene-modified polyvinyl alcohol resin having high crystallinity as a binder for a color developing layer and a protective layer has improved water resistance and printability. I found something that could be improved. That is, the pressure-sensitive recording color developing sheet of the present invention is a pressure-sensitive recording color developing sheet provided on a support with at least a color developing layer containing a binder and an electron-accepting color developing agent. It is characterized by containing an ethylene-modified polyvinyl alcohol-based resin. Also,
The color-developing sheet for pressure-sensitive recording of the present invention is provided on a support with at least a color-developing layer containing a binder and an electron-accepting color developer, and a protective layer mainly composed of a binder on the color-developing layer. Wherein the protective layer contains an ethylene-modified polyvinyl alcohol-based resin. In these pressure-sensitive recording developer sheets, it is desirable that the ethylene-modified polyvinyl alcohol-based resin has an ethylene conversion rate of 1 to 20%.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below. The color-developing sheet for pressure-sensitive recording of the present invention comprises a color-developing layer provided on a support, a color-developing layer provided on a support, and a color-developing layer provided on a support. In the pressure-sensitive recording color developing sheet provided with a protective layer on the layer, the protective layer, each using an ethylene-modified polyvinyl alcohol-based resin as a binder, provided with a color developing layer on a support, In a pressure-sensitive recording color developing sheet provided with a protective layer on the color developing layer,
An ethylene-modified polyvinyl alcohol-based resin may be used for both the color developing layer and the protective layer.

The ethylene-modified polyvinyl alcohol in the present invention is particularly preferably a saponified random copolymer having a vinyl ester unit represented by the following general formula (1).

[0016]

Embedded image

(Wherein R ¹ , R ² and R ³ represent a hydrogen atom or a hydrocarbon group, R ² and R ³ may be bonded to each other to form a cyclic hydrocarbon group, R ¹ , R ² and R ³
May combine with each other to form a cyclic hydrocarbon group.
n and m are natural numbers. Here, examples of the hydrocarbon group of R ¹ , R ² , and R ³ include a methyl group, an ethyl group, and a propyl group, and a cyclic hydrocarbon group formed by combining R ² and R ³ with each other. Is
Examples include a cyclohexyl group and a phenyl group. Also,
Examples of the cyclic hydrocarbon group formed by combining R ¹ , R ² and R ³ with each other include an adamantyl group.

In the ethylene-modified polyvinyl alcohol of the present invention, the ratio of the vinyl alcohol monomer component of the polyvinyl alcohol to the ethylene monomer is preferably 80:20.
Desirably, it is a random polymer of ~ 99: 1. In the case of the ethylene-modified polyvinyl alcohol, in order to have water solubility and sufficient water resistance, the ethylene conversion ratio is 20 mol% (that is, the ratio of the vinyl alcohol monomer component to the ethylene monomer is 80:20). １1 mol% (99: 1 in the ratio of vinyl alcohol monomer component to ethylene monomer) is desirable, and more preferably, the ethylene conversion is 5 to 10 mol%. In the case of unmodified ethylene alcohol, sufficient water resistance and chemical resistance cannot be obtained. If the ethylene conversion ratio exceeds 20 mol%, the solubility in water is undesirably reduced.

The polymerization degree of the ethylene-modified polyvinyl alcohol is preferably from 300 to 4000, and is preferably from 500 to 2,000 from the viewpoint of coating properties and water resistance. The degree of saponification of the ethylene-modified polyvinyl alcohol is preferably at least 85 mol%, more preferably at least 98 mol%. Saponification degree is 85
If the amount is less than mol%, sufficient water resistance and chemical resistance cannot be obtained.

These ethylene-modified polyvinyl alcohols may be further modified with other functional groups within a range that does not adversely affect the performance and the stability of the coating solution. Specific examples include a carboxyl group, a terminal alkyl group, an amino group,
Sulfonic acid group, terminal thiol group, silanol group, amide group and the like. A carboxyl-modified or amino-modified sulfonic acid group is effective for imparting the solubility of highly syndiophilic polyvinyl alcohol.

In the color-developing layer and the protective layer, other binder components may be used in addition to ethylene-modified polyvinyl alcohol, if necessary. These binders include a water-soluble binder composed of a water-soluble polymer, a water-insoluble There is a binder. Examples of the water-soluble binder include methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, starch, gelatin, gum arabic, casein, styrene-maleic anhydride copolymer hydrolyzate, ethylene-maleic anhydride copolymer hydrolyzate, isobutylene- Examples include a maleic anhydride copolymer hydrolyzate, polyvinyl alcohol, modified polyvinyl alcohol, polyacrylamide, and the like. However, the combined use of a water-soluble polymer may cause a decrease in water resistance,
Attention should be paid to the amount and type used together.

As the water-insoluble binder, synthetic rubber latex or synthetic resin emulsion is generally used, and examples thereof include styrene-butadiene rubber latex, acrylonitrile-butadiene rubber latex, methyl acrylate-butadiene rubber latex, and vinyl acetate emulsion. The amount of the binder used is 10 to 500% by weight, preferably 50% by weight, based on the pigment contained in the protective layer.
４００400% by weight.

Further, in order to further improve the water resistance, it is effective to use a crosslinking agent and a catalyst for accelerating the reaction.
Specific examples of the crosslinking agent include an epoxy compound, a blocked isocyanate, a vinyl sulfone compound, an aldehyde compound, a methylol compound, boric acid, a carboxylic anhydride, a silane compound, a chelate compound, and a halide. Preferably, the pH can be adjusted to 6.0 to 7.5. Known catalysts such as acids and metal salts can be used as the catalyst, and similarly, the pH of the coating solution is adjusted to 6.0 to 6.0.
Those that can be adjusted to 7.5 are preferred.

As the epoxy compound, those having two or more functions can be used. For example, dibromophenyl glycidyl ether, dibromoneopentyl glycol diglycidyl ether, emulsion of epoxy cresol novolak resin, modified bisphenol A type epoxy emulsion,
Adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, hydroquinone diglycidyl ether, bisphenol S glycidyl ether, terephthalic acid diglycidyl ether, glycidyl phthalimide, propylene polypropylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, Allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, phenol (EO) 5 glycidyl ether, p-tert-butylphenyl glycidyl ether, lauryl alcohol (EO) 15 glycidyl ether, carbon number 1
Glycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, ethylene polyethylene glycol diglycidyl ether of an alcohol mixture of 2 to 13 Sorbitol polyglycidyl ether, sorbitan polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl luteris (2-hydroxyethyl) isocyanurate, and the like. Among them, glycidyl ethers are particularly preferred.

The epoxy compound effective for the present invention preferably has an epoxy equivalent of 70 to 1000 WPE. When the epoxy equivalent exceeds 1000 WPE, it becomes difficult to impart water resistance, which is not preferable.

The term "blocked isocyanate" refers to a compound obtained by masking a terminal isocyanate group of an isocyanate with a blocking agent. Blocked isocyanates include:
For example, (a) an isocyanate compound in which a block of a hydrophilic group comprising a carbamoyl sulfonate group (—NHCOSO ₃ —) is formed at the end of the isocyanate compound to block an active isocyanate group, and (b) isopropylidene malonate Those with blocked active isocyanate groups. Examples of the blocked isocyanate include (c) a compound obtained by reacting HDI isocyanurate, isopropylidene malonate, and triethylamine, in which an active isocyanate group is blocked with a phenol.
When such a blocked isocyanate is mixed with and heated with ethylene-modified polyvinyl alcohol, the ethylene-modified polyvinyl alcohol is cross-linked and reformed to make the ethylene-modified polyvinyl alcohol water-resistant.

As the vinyl sulfone compound, those described in JP-A-53-57257, JP-A-53-41221, JP-B-49-13563, JP-B-47-24259, and the like can be used. It is.

Examples of the aldehyde compounds include monoaldehydes such as formaldehyde and acetaldehyde, and polyhydric aldehydes such as glyoxal, glutaraldehyde and dialdehyde starch. Examples of the methylol compound include methylol melamine and dimethylol urea. In the case of ethylene-modified polyvinyl alcohol,
Aldehyde compounds are particularly preferred as the crosslinking agent.

The amount of the crosslinking agent to be used for the ethylene-modified polyvinyl alcohol is desirably 3 to 50 parts by weight of the crosslinking agent for 100 parts by weight of the ethylene-modified polyvinyl alcohol. When the amount of the crosslinking agent is less than 3 parts by weight, the degree of crosslinking modification is low, and the water resistance and chemical resistance become insufficient. On the other hand, when the amount exceeds 50 parts by weight, the liquid stability decreases, and Absent.

Further, if necessary, a general organic pigment or an inorganic pigment, for example, calcium carbonate, aluminum hydroxide, barium sulfate, titanium oxide, talc, wax, kaolin, calcined kaolin may be added to the color developing layer and the protective layer. , Non-crystalline silica, colloidal silica, urea-formalin resin powder, polyethylene resin powder, and the like.

Further, in order to further increase the water resistance, the color developing layer and the protective layer may further include a water repellent or an oil repellent such as montan wax, paraffin wax, carnauba wax, microcrystalline wax, polyethylene wax, silicone, A fluorine resin or the like may be contained.

As the support, paper made of wood pulp or synthetic paper made of a plastic material is used in the same manner as a conventional pressure-sensitive recording color developing sheet.

Examples of the color developer contained in the color developer sheet for pressure-sensitive recording of the present invention include clays such as acid clay, activated clay, attapulgite, zeolite, bentonite and kaolin; metal salts of aromatic carboxylic acids; Phenol formaldehyde resin and the like can be mentioned. Above all, metal salts of aromatic carboxylic acids are preferred. Preferred specific examples of the aromatic carboxylic acid metal salt include 3,5-di-t-butylsalicylic acid, 3,5-di-t-octylsalicylic acid,
3,5-di-t-nonylsalicylic acid, 3,5-di-t-
Dodecyl salicylic acid, 3-methyl-5-t-dodecyl salicylic acid, 3-t-dodecyl salicylic acid, 5-t-dodecyl salicylic acid, 5-cyclohexyl salicylic acid, 3,
5-bis (α, α-dimethylbenzyl) salicylic acid, 3
-Methyl-5- (α-methylbenzyl) salicylic acid, 3
-(Α, α-dimethylbenzyl) -5-methylsalicylic acid, 3- (α, α-dimethylbenzyl) -6-methylsalicylic acid, 3- (α-methylbenzyl) -5- (α, α
-Dimethylbenzyl) salicylic acid, 3- (α, α-dimethylbenzyl) -6-ethylsalicylic acid, 3-phenyl-5- (α, α-dimethylbenzyl) salicylic acid, carboxy-modified terpene phenol resin, 3,5-bis ( α
Zinc salt, nickel salt, aluminum salt, calcium salt and the like, such as salicylic acid resin which is a reaction product of (-methylbenzyl) salicylic acid and hensyl chloride. The aromatic carboxylic acid metal salt is a ball mill,
It can be mechanically dispersed in an aqueous system using an art writer, a sand grinder, or the like, or can be used after being dissolved in an organic solvent.

Examples of the organic solvent for dissolving the metal salt of aromatic carboxylic acid include diisopropylnaphthalene, 1-phenyl-1-xylylethane, 1-phenyl-1-isopropylphenylethane, 1-phenyl-1-ethylphenylethane, toluene, Examples thereof include xylene, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, ethyl acetate, butyl acetate, amyl acetate, methylene chloride, butanol, paraffin, and kerosene.

A solution prepared by dissolving a metal salt of an aromatic carboxylic acid in the above organic solvent is added to water containing a dispersant in an amount of 5 to 120% by weight, preferably 50 to 100% by weight, and emulsified and dispersed. Subsequently, the organic solvent may be removed by heating the emulsified dispersion.

As the dispersant, an ionic or nonionic surfactant or a water-soluble polymer compound can be used. Surfactants include alkyl benzene sulphonates, alkyl naphthalene sulphonates, alkyl sulphonates, dialkyl sulphosuccinates, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, partial esters of polyhydric alcohol fatty acids, etc. Is mentioned. Further, as the water-soluble polymer compound, polyvinyl alcohol modified polyvinyl alcohol,
Examples thereof include polyacrylamide, sodium polyacrylate, polyvinyl ether, sodium polystyrene sulfonate, and maleic anhydride copolymer.

The metal salt of the aromatic carboxylic acid is generally used by dissolving it in an organic solvent in an amount of 10 to 200% by weight.

The color-developing layer of the color-developing sheet for pressure-sensitive recording of the present invention is formed by preparing a coating solution for forming a color-developing layer containing the above-mentioned color developing agent, coating the solution on a support, and drying. Can be.

The coating solution for forming a color developing layer is prepared by adding a binder conventionally used for a color developing layer to the color developing agent dispersion as described above.
For example, polyvinyl alcohol, maleic acid-based copolymer, methyl cellulose, carboxymethyl cellulose,
Hydroxypropyl cellulose, gum arabic, starch, gelatin, polyvinylpyrrolidone, casein, styrene-butadiene rubber latex, acrylonitrile-butadiene rubber latex, polyvinyl acetate, etc.
It is adjusted by adding and mixing an inorganic pigment dispersion.

The content of the binder in the coating solution for forming a color developing layer is preferably 10 to 3 of the total solids in the coating solution.
It is preferably 0% by weight. When the content is less than the above range, the coating strength of the color developing layer is reduced, and when the content is more than the above range, the coloring density tends to decrease.

The formation of the color-developing layer and the protective layer on the support can be carried out by a method known per se, for example, an air knife coating method, a blade coating method, a curtain coating method and the like. The final amount of the developer is 0.1 g / m ² to
3.0 g / m ² , preferably 0.2 g / m ^{2 to} 1.0 g / m
m ² is appropriate. Further, the pressure-sensitive recording color-developing sheet used in combination with the pressure-sensitive recording color developing sheet of the present invention,
Any conventionally known ones can be used.

[0042]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples. The concentration used in the text is% by weight. Next, the present invention will be described in more detail with reference to Examples and Comparative Examples.

Example 1 [Preparation of Capsule Solution A for Coloring Layer] As a coloring agent, 5.0 g of crystal violet lactone and 1.0 g of benzoylleucomethylene blue were dissolved in 100 g of diisopropylnaphthalene. To the obtained oily liquid, 60 g of IP Solvent 1620 (manufactured by Idemitsu Petrochemical Co., Ltd.) as a paraffinic solvent and carbodiimide-modified diphenylmethane diisocyanate (manufactured by Nippon Polyurethane Co., Ltd., trade name "Millionate MT") as a polyvalent isocyanate
L ") 10 g, a biuret of hexamethylene diisocyanate (trade name" Sumidur N3200 ", manufactured by Sumitomo Bayer Urethane Co., Ltd.) and a butylene oxide adduct of ethylenediamine (addition mole of butylene oxide to ethylenediamine) as an alkylene oxide adduct of an amine Number 16.8 mol, molecular weight 126
7) 3.0 g was dissolved to prepare a primary solution.

Next, in 140 g of water, polyvinyl alcohol having an ethylene conversion rate of 5 mol% (polymerization degree: 550, saponification degree: 9)
(8.5 mol%) and 5 g of carboxymethylcellulose were dissolved, and 4 g of a 10% aqueous solution of polyoxyethylene sorbitan oleate as a surfactant was added thereto to prepare a secondary solution. While vigorously stirring the secondary solution, the primary solution was poured into the secondary solution to form an oil-in-water emulsion. Oil droplet size is 5.
At 0 μm, the stirring was weakened. Then, 100 g of water at 20 ° C. was added to the emulsion, and 0.5 g of tetraethylenepentamine was further added.
The temperature was raised to 0 ° C. and maintained at this temperature for 90 minutes.

[Preparation of Coating Solution A for Forming Coloring Layer] A polyvinyl alcohol having an ethylene conversion rate of 5 mol% (degree of polymerization 550, degree of saponification 98.5) was added to the capsule solution thus obtained.
100 g of a 10% aqueous solution and 60 g of starch (average particle size 15 μm) were added. Then, water was added to adjust the solid content concentration to 20% by weight, and the coating solution A for forming a color-forming layer was formed.
Was prepared.

[Preparation of Developer Dispersion A] 100 g of zinc 3,5-bis (α-methylbenzyl) salicylate was dissolved in 80 g of xylene.

This xylene solution was treated with polyvinyl alcohol having a degree of ethylene conversion of 5 mol% (polymerization degree 550, saponification degree 9).
(8.5 mol%) in 120 g of a 4% aqueous solution, and further 4 g of a 10% aqueous solution of polyoxyethylene sorbitan oleate as a surfactant, and the average particle size of the emulsion becomes 1.0 μm using a homogenizer. Was prepared as described above.

Next, 180 g of water was added to the emulsified dispersion and heated, and xylene was removed from the emulsified dispersion by azeotropic distillation with water. The solid content was adjusted to 30% and the color was developed. An agent dispersion was obtained.

[Preparation of Coating Solution A for Forming Developing Layer] 180 parts by weight of calcium carbonate (average particle size: 0.5 μm), 24 parts by weight of zinc oxide, 31 parts by weight of kaolin, 4 parts by weight of a 40% sodium hexametaphosphate aqueous solution, An inorganic particle dispersion was prepared by uniformly dispersing 240 parts by weight of water using a sand grinder so as to have an average particle size of 1 μm.

50 parts by weight of the above-mentioned developer dispersion and 400 parts by weight of the above-mentioned inorganic particle dispersion are mixed, and the resulting mixture is made of polyvinyl alcohol having an ethylene conversion rate of 5 mol% (degree of polymerization 550, degree of saponification 98.%). 5 mol%) 10% aqueous solution 320
A weight part was added and water was adjusted so that the solid content concentration became 20% to prepare a coating solution A for forming a developing layer.

[Preparation of pressure-sensitive recording coloring sheet] 40 g /
on one side of the m ² base paper, a coloring layer forming coating solution A above 5.
It was applied by a curtain coating method so as to be applied at a solid content of 0 g / m ² and dried at 100 ° C. to obtain a pressure-sensitive recording coloring sheet. On one side of the [pressure sensitive recording color-developing Preparation of Sheet] 40 g / m ² base paper, the color developing layer coating solution A above as applied in the solid content of 5.0 g / m ^2, a curtain coating It was applied by a method and dried at 100 ° C. to obtain a color developing sheet for pressure-sensitive recording. Examples 2 and 3 Instead of using the polyvinyl alcohol having an ethylene conversion of 5 mol% in Example 1, polyvinyl alcohol having an ethylene conversion of 7.5 mol% (Example 2) and an ethylene conversion of 7 mol% were used. 0.5 mol% of 10
A color developing sheet for pressure-sensitive recording was obtained in the same manner as in Example 1 except that mol% of polyvinyl alcohol (Example 3) (all of which had a saponification degree of 98.5 mol% and a polymerization degree of 550) was used.

Examples 4 and 5 Instead of using the polyvinyl alcohol having a polymerization degree of 550 in Example 1, polyvinyl alcohol having a polymerization degree of 1000 (Example 4) and polyvinyl alcohol having a polymerization degree of 1750 (Example 5) (in each case) A pressure-sensitive recording developer sheet was obtained in the same manner as in Example 1, except that the saponification degree was 98.5 mol% and the ethylene conversion was 5 mol%.

Examples 6 to 9 Carboxy modification (1 mol% of itaconic acid) by copolymerization (Example 6), modification of primary amino group (2 mol%) by changing to ethylene modified polyvinyl alcohol of Example 2 Example 7], silanol conversion (1 mol%) [Example 8],
Example 9 A pressure-sensitive recording developer sheet was obtained in the same manner as in Example 2 except that ethylene-modified polyvinyl alcohol modified with sulfonic acid (2 mol%) [Example 9] was used.

Example 10 The same procedure as in Example 2 was carried out except that an ethylene-modified polyvinyl alcohol having a saponification degree of 96.0 mol% was used instead of the ethylene-modified polyvinyl alcohol having a saponification degree of 98.5 mol%. A color developing sheet for pressure-sensitive recording was obtained by the method.

Comparative Example 1 A non-ethylene-modified polyvinyl alcohol (PVA105: manufactured by Kuraray Co., Ltd.) was used in place of the polyvinyl alcohol having an ethylene conversion of 5 mol% in the same manner as in Example 1. A color-developing sheet for pressure-sensitive recording was obtained by the method.

Examples 11 and 12 [Preparation of Coating Solution for Protective Layer] 80 g of aluminum hydroxide (manufactured by Showa Denko KK, Hijilite H42) was dispersed together with 160 g of a 0.5% aqueous solution of sodium hexametaphosphate with a homogenizer. 40 g of this dispersion, 2500 g of a 6% aqueous solution of ethylene-modified polyvinyl alcohol used in Example 2,
15 g of 40% glyoxal, dispersion of 40% zinc stearate (high micron F930 average particle size 1 manufactured by Chukyo Yushi Co., Ltd.)
(.About.0.8 .mu.m) to obtain a protective layer coating solution. This protective layer coating liquid was applied on the color developing layer of the pressure-sensitive recording color developing sheets of Example 2 and Comparative Example 1 obtained above using a wire bar so as to have a dry coating amount of 2 g / m ² . 50
It was dried in an oven at ℃ to obtain a color developing sheet for pressure-sensitive recording.

The following evaluation was performed on each of the pressure-sensitive recording developer sheets obtained as described above. [Water resistance test] After superimposing a color-developing sheet on the pressure-sensitive recording color developing sheet prepared as described above and performing printing,
The pressure-sensitive recording developer sheet was immersed in water for three days, taken out of the water, and rubbed with a fingertip three times in a wet state with the fingertip. The sex was evaluated. The evaluation criteria are as follows. A: The coating film is not affected at all and there is no practical problem. B: The coating film only slightly changed in gloss after drying, and there was no problem in practical use. C: There was a sign that the coating film was slightly peeled off, but it was completely readable, so there was no problem in practical use. D: Peeling occurred at a very small portion of the coating film, and the film could not be read. E: Most of the coating film peeled and could not be read, and there was a problem in practical use. F: The coating film was completely peeled and could not be read, and there was a problem in practical use.

[Color-forming test] The color-developing sheet for pressure-sensitive recording and the color-developing sheet were colored by applying a static pressure of 500 kg / cm ² thereon so that the color-developing layer and the color-developing layer were overlapped.
The density of the color image was measured with a Macbeth densitometer, and the color development was evaluated. The evaluation criteria are as follows. A: The coloring density is as high as 0.95 or more, and there is no practical problem. B: Coloring density is slightly low at about 0.70, which is problematic in practical use. C: Color density is very low at about 0.50, which is problematic in practical use.

[Printing suitability test] A hydrophilic non-image area and a hydrophobic image area (solid area) were prepared from a PS plate by plate making. The coloring ink was SCR77 grass (manufactured by Toyo Ink Co., Ltd.). ) Made by "Miyastar 18" offset printing machine (fountain solution is spray type) at a printing speed of 150 m / min. The paper dust and the coating-layer peeling dust attached to the non-image area were transferred to the adhesive portion of the cellophane tape, and the stained state and a blanket portion were visually observed by photographing. , D, E, F)
Was evaluated. The practical level is C or higher. Water resistance test,
Table 1 shows the results of the color development test and the printability test.

[0060]

[Table 1]

As is clear from the data in Table 1, the color developing sheet for pressure-sensitive recording using the ethylene-modified polyvinyl alcohol-based resin according to the present invention has excellent water resistance, printability and color development, and is not suitable for practical use. On the other hand, the color developing sheet for pressure-sensitive recording in which no ethylene-modified polyvinyl alcohol-based resin was used was extremely poor in water resistance and printability.

[0062]

The color-developing sheet for pressure-sensitive recording of the present invention has remarkably excellent performance that the color-developing layer has excellent water resistance without lowering of color density or occurrence of color fogging. The advantage is that it can be easily, efficiently and inexpensively manufactured.

Claims (3)

[Claims] 1. A pressure-sensitive recording color developing sheet provided with a color developing layer containing at least a binder and an electron-accepting color developing agent on a support, wherein the binder contains an ethylene-modified polyvinyl alcohol-based resin. A color developing sheet for pressure-sensitive recording. 2. A pressure-sensitive recording apparatus comprising a support and a developing layer containing at least a binder and an electron-accepting developer, and a protective layer containing a binder as a main component on the developing layer. In the color developing sheet, the protective layer contains an ethylene-modified polyvinyl alcohol-based resin. 3. The pressure-sensitive recording color developing sheet according to claim 1, wherein the ethylene-modified polyvinyl alcohol-based resin has an ethylene conversion rate of 1 to 20%.