JPH1178230A - Development sheet for pressure-sensitive copy paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the title development sheet developing desensitizing effect even if a desensitizing ink build-up amt. is little especially at a time of desensitizing printing and excellent in color forming properties, preservability and offset printability as pressure-sensitive copy paper. SOLUTION: In a development sheet for pressure-sensitive copy paper constituted by coating a support with a coating soln. containing a polyvalent metal salt of a nuclear substd. aromatic carboxylic acid derivative and pigment and drying the coated support, at least one component selected from a dicyandiamide/formalin polycondensate and a dicyanamide/polyamine polycondensate is added to the coating soln. in an amt. of 1-10 wt.% with respect to the total wt. of the polyvalent metal salt of the nuclear substd. aromatic carboxylic acid derivative and the pigment and modified polyvinyl alcohol containing silicon in its molecule is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color-developed sheet for pressure-sensitive copying paper, and more particularly to a pressure-sensitive copying in which a desensitizing effect is exhibited even when the amount of desensitizing ink is small at the time of desensitizing printing. The present invention relates to a color-developed sheet for pressure-sensitive copying paper, which is excellent in color developing properties, storability, and suitability for offset printing as paper.

[0002]

2. Description of the Related Art A pressure-sensitive copying paper is prepared by applying a microcapsule composition mainly composed of a microcapsule containing a hydrophobic core substance in which an electron-donating color former (leuco dye) is dissolved to one side of a support. Paper and one side of the support were coated with a developer main component mainly composed of an electron-accepting color developer that developed a color when contacted with the above color former, and the microcapsule composition was coated on the opposite side. There is a middle sheet and a lower sheet with a developer composition applied on one side of the support, and these three types of sheets are practically used as a copy set by combining an upper sheet, a lower sheet, or an upper sheet, a middle sheet, and a lower sheet in this order. Has been Self-contained pressure-sensitive copying paper (self-contained paper), in which a color former and a developer are coated on the same surface of the support to enable pressure-sensitive recording with one sheet, is also well known as a form of pressure-sensitive copying paper. Have been.

Hitherto, pressure-sensitive copying paper has been mainly used as a slip (form) sheet, and the format of the slip has been often printed by a printing professional by letterpress printing or offset printing. However, in recent years, demands for pressure-sensitive copying paper have been diversified, for example, in general slips, delivery slips, contract documents, and the like, in accordance with the expansion of uses thereof. Depending on the configuration of the voucher, there is a case where a recording unnecessary portion is provided on the surface of the middle and lower sheets where the developer is applied. In such a case, the desensitizing ink containing the desensitizer is applied by a printing machine or the like. A method has been adopted in which desensitization is achieved by coating on that part of the surface.

[0004]

However, in recent years, in the production of pressure-sensitive copying paper for economic reasons, as the speed of the color developer layer coating increases and the amount of coating decreases, the use of desensitized printing has become difficult. If a large amount of desensitizing ink is not applied, the desensitizing effect will not be exhibited, and if a large amount of desensitizing ink is applied, drying of the desensitizing ink will be delayed, and printing troubles such as set-off stains will increase. Is coming. Such a problem is remarkable in the case of black coloring which is less likely to be desensitized than blue coloring.

SUMMARY OF THE INVENTION An object of the present invention is to provide a pressure-sensitive copying method in which at least a desensitizing ink volume at the time of desensitizing printing exhibits at least a desensitizing effect, and is excellent in color-forming properties, preservability and suitability for offset printing as pressure-sensitive copying paper. An object of the present invention is to provide a color developing sheet for paper.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a color developing solution for a pressure-sensitive copying paper is obtained by coating a coating solution containing a polyvalent metal salt of a nucleus-substituted aromatic carboxylic acid derivative and a pigment on a support and drying the coating solution. In the sheet, at least one selected from dicyandiamide-formalin polycondensate and dicyandiamide-polyamine polycondensate is added to the coating solution in an amount of 1% based on the total weight of the polyvalent metal salt of the nucleus-substituted aromatic carboxylic acid derivative and the pigment. The present invention relates to a color-developing sheet for pressure-sensitive copying paper, characterized in that a modified polyvinyl alcohol containing 10 to 10% by weight and containing silicon in a molecule is used.

[0007]

DETAILED DESCRIPTION OF THE INVENTION As described above, the present invention provides a developer layer using such a polyvalent metal salt of a nucleus-substituted aromatic carboxylic acid derivative, wherein a specific amount of a specific copolymer is contained and a specific modification is performed. This uses polyvinyl alcohol. In the present invention, by using a polyvalent metal salt of a nucleus-substituted aromatic carboxylic acid derivative as a color developer, a color-developing sheet for pressure-sensitive copying paper having excellent color developing properties is obtained, and a nucleus-substituted aromatic color is formed in a color developing layer. By adding 1 to 10% by weight of a polycondensate of dicyandiamide-formalin and / or a polycondensate of dicyandiamide-polyamine with respect to the total weight of the polyvalent metal salt of the carboxylic acid derivative and the pigment, the desensitizing printing suitability is improved. By the way, if the amount is less than 1% by weight, the desired effect of improving the desensitized printing suitability cannot be obtained, and if it exceeds 10% by weight, the storage stability of the pressure-sensitive copy recorded image is reduced.

The developing layer contains 1 to 10% by weight of dicyandiamide-formalin condensate and / or dicyandiamide-polyamine polycondensate based on the total weight of the polyvalent metal salt of the nucleus-substituted aromatic carboxylic acid derivative and the pigment. Although the operation sustainability of the offset printing was lowered by performing this, it was improved by using a modified polyvinyl alcohol containing silicon in the molecule. Further, by containing a dicyandiamide-formalin condensate and / or a dicyandiamide-polyamine polycondensate in an amount of 1 to 10% by weight, it is possible to improve the inkjet recording suitability.

The silicon-containing modified PV used in the present invention
A has been disclosed in Japanese Patent Publication No. 59915/1993. This silicon-containing modified PVA is:
Any material may be used as long as it contains silicon in the molecule. It is particularly preferably used if the silicon contained in the molecule has a reactive substituent such as an alkoxyl group, an acyloxyl group, a hydroxyl group obtained by hydrolysis or the like, or an alkali metal base thereof. The production method of the modified PVA is described in detail in Japanese Patent Publication No. 59915/1992. According to the publication, silicon-modified PVA is:
It is manufactured by the following two methods.

[Example of Method of Introducing Silicon into PVA or Modified Polyvinyl Acetate Containing Carboxyl Group or Hydroxyl Group by Post-Modification Using Silylating Agent] Organic solvent which does not react with the silylating agent, for example, benzene, toluene, A silylating agent is dissolved in xylene, hexane, heptane, ether, acetone, or the like, and suspended in the solution under stirring with powdered PVA or the above-mentioned modified polyvinyl acetate, at a temperature in the range of room temperature to the boiling point of the silylating agent. , A silicon-modified PVA can be obtained by reacting a silylating agent with PVA or the above-mentioned modified polyvinyl acetate, or by further saponifying a vinyl acetate unit with an alkali catalyst or the like.

The silylating agent used in the post-modification includes organohalogen silanes such as trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, vinyltrichlorosilane, diphenyldichlorosilane and triethylfluorosilane, and trimethylacetoxysilane. , Organosilicon ester such as dimethyldiacetoxysilane, trimethylmethoxysilane, organoalkoxysilane such as dimethyldimethoxysilane, trimethylsilanol, organosilanol such as diethylsilanediol, aminoalkylsilane such as N-aminoethylaminopropyltrimethoxysilane, Organo silicon isocyanate such as trimethyl silicon isocyanate and the like can be mentioned. The introduction rate of the silylating agent, that is, the degree of modification can be arbitrarily adjusted depending on the amount of the silylating agent used and the reaction time. The degree of polymerization and saponification of the resulting silicon-containing modified PVA can be arbitrarily adjusted by the degree of polymerization of the PVA used, the degree of saponification or the degree of polymerization of the modified PVA and the saponification reaction.

[Method of saponifying a copolymer of vinyl ester and olefinically unsaturated monomer containing silicon in the molecule] In an alcohol, a vinyl ester and a silicon-containing olefinically unsaturated monomer are reacted with each other. After copolymerization using a radical initiator, a silicon-containing modified PVA can be obtained by saponifying the copolymer by adding an alkali or acid catalyst to an alcohol solution of the copolymer. Examples of the vinyl ester used in the above method include vinyl acetate, vinyl propionate, vinyl formate and the like, and vinyl acetate is most preferable from the viewpoint of economy. Examples of the silicon-containing olefinically unsaturated monomer used in the above method include vinylsilane represented by the following formula (I) and (meth) acrylamide-alkylsilane represented by the following formula (II).

[0013]

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[0014]

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Here, n is 0 to 4, m is 0 to 2, R ₁ is an alkyl group having 1 to 5 carbon atoms (such as methyl and ethyl), and R ₂ is an alkoxyl group or an acyloxyl group having 1 to 40 carbon atoms. Here, the alkoxyl group and the acyloxyl group may have a substituent containing oxygen), R ₃ is a hydrogen atom or a methyl group, R ₄ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and R ₅ is A divalent organic residue in which an alkylene group having 1 to 5 carbon atoms or a chain carbon atom is mutually bonded by oxygen or nitrogen is shown. When two R ₁ are present in the same monomer, R ₁ may be the same or different. When two or more R ₂ are present in the same monomer, R ₂ may be the same or different.

Specific examples of the vinylsilane represented by the formula (I) include, for example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris- (β-methoxyethoxy) silane, vinyltriacetoxysilane, allyltrimethoxysilane, allyltrimethoxysilane. Acetoxysilane, vinylmethyldimethoxysilane, vinyldimethylmethoxysilane, vinylmethyldiethoxysilane, vinyldimethylethoxysilane, vinylmethyldiacetoxysilane, vinyldimethylacetoxysilane, vinylisobutyldimethoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane , Vinyltrihexyloxysilane, vinyldimethoxyhexyloxysilane, vinylmethoxydihexyloxysilane, vinyltrioctyloxysilane, vinyldimethoxy Ok Ciro silane, vinyl methoxy dioctyloxy B silanes, vinyl dimethoxy Lau Lilo silane, vinyl methoxy dilaurate Lilo silane,
Examples thereof include vinyl dimethoxy oleyloxy silane, vinyl methoxy dioleoxy silane, and polyethylene glycolated vinyl silane represented by the following general formula.

[0017]

Embedded image (Where R ₁ and m are the same as above, and x represents 1 to 20)
And the like.

Specific examples of the (meth) acrylamide-alkylsilane represented by the general formula (II) include, for example,
3- (meth) acrylamido-propyltrimethoxysilane, 3- (meth) acrylamido-propyltriethoxysilane, 3- (meth) acrylamido-propyltri (β-methoxyethoxy) silane, 2- (meth) acrylamido-2- Methylpropyltrimethoxysilane,
2- (meth) acrylamido-2-methylethyltrimethoxysilane, N- (2- (meth) acrylamido-ethyl) aminopropyltrimethoxysilane, 3- (meth) acrylamido-propyltriacetoxysilane,
2- (meth) acrylamido-ethyltrimethoxysilane, 1- (meth) acrylamido-methyltrimethoxysilane, 3- (meth) acrylamido-propylmethyldimethoxysilane, 3- (meth) acrylamido-propyldimethylmethoxysilane, 3- (N-methyl- (meth) acrylamide) -propyltrimethoxysilane and the like.

The modified PV used in the present invention
In producing A, in copolymerizing a vinyl ester and a silicon-containing olefinically unsaturated monomer, an unsaturated monomer copolymerizable with the monomer other than the above two components, for example, styrene, Alkyl vinyl ether,
Olefins such as vinyl versatate, (meth) acrylamide, ethylene, propylene, α-hexene, α-octene, (meth) acrylic acid, crotonic acid, (anhydrous)
Unsaturated acids such as maleic acid, fumaric acid, itaconic acid and the like, alkyl esters and alkali salts thereof, sulfonic acid-containing monomers such as 2-acrylamido-2-methylpropanesulfonic acid and the like and alkali salts thereof, trimethyl-3- ( 1-
(Meth) acrylamide-1,1-dimethylpropyl)
Ammonium chloride, trimethyl-3- (1- (meth) acrylamidopropyl) ammonium chloride,
It is also possible to add a small amount of a cationic monomer such as 1-vinyl-2-methylimidazole and a quaternary compound thereof.

As described above, modified PV containing silicon in the molecule
Although A has been described in detail, among these, copolymerization is more preferable than post-modification in view of easiness of industrial production. Further, among the modified PVAs by copolymerization, the copolymer saponified with a silicon-containing olefinically unsaturated monomer represented by the formula (I) has a viscosity stability of an aqueous solution and an alkali aqueous solution. It is excellent in stability and water resistance when formed into a film, and is preferably used. On the other hand, the saponified copolymer of the silicon-containing olefinically unsaturated monomer represented by the formula (II) is a silicon-containing olefin represented by the formula (I) in terms of viscosity stability of an aqueous solution and stability against alkali. It is slightly inferior to the saponified copolymer with the unsaturated monomer, but has the characteristic that the aqueous solution is hardly foamed or, when formed into a film, exhibits more excellent performance in terms of barrier properties to organic solvents. And is preferably used in some cases.

The modification degree of the modified PVA, that is, the modified P
The silicon content in VA can be appropriately selected according to the purpose, but is usually 0.01 to 10 mol%, preferably 0.1 to 2.5 mol% as a silicon-containing monomer unit in the molecule.
It is. The polymerization degree of the modified PVA (both post-modified PVA and modified PVA by copolymerization) is usually 300 to 3000,
Preferably from 600 to 3000, more preferably 100
The degree of saponification is selected from the range of 70 to 100 mol%. The coating amount of the silicon-containing polyvinyl alcohol is preferably 2 to 30% by weight of the total solids, more preferably 4 to 20% by weight. When the coating amount is less than 2% by weight, the effect on the surface strength decreases, and when the coating amount exceeds 30% by weight, the color developability decreases.

The dicyandiamide-formalin polycondensate used in the present invention has the following structure.

[0023]

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The dicyandiamide-polyamine polycondensate used in the present invention has, for example, the following structure.

[0025]

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Examples of the polyamine copolymerized with dicyandiamide include ethylenediamine, diethylenetriamine,
Triethylenetetramine, dipropylenetriamine, N
-Aminopropylcyclohexylamine, 1,4-diaminocyclohexane, xylylenediamine, isophoronediamine, N-aminoethylpiperazine, N, N'-
Bis (aminopropyl) piperazine, N-aminopropylmorpholine, 1,3-bis (aminomethyl) cyclohexane and the like can be mentioned. As the degree of polymerization of the copolymer,
It is sufficient that the effects of the present invention can be exerted, and it can be widely used from relatively low molecular weight to high molecular weight. Generally, those having p and q of 10 to 2,000 are preferable, but those having a value outside the above range can be used.

Examples of the developer used in the present invention include, for example, 3-phenylsalicylic acid, 3-cyclohexylsalicylic acid, 3-tert-butyl-5-methylsalicylic acid, 3,5-di-tert-butylsalicylic acid, 3-methyl -5-benzylsalicylic acid, 3-phenyl-5- (α,
α-dimethylbenzyl) salicylic acid, 3-cyclohexyl-5- (α, α-dimethylbenzyl) salicylic acid, 3
-(Α, α-dimethylbenzyl) -5-methylsalicylic acid, 3,5-di-cyclohexylsalicylic acid, 3,5-di- (α-methylbenzyl) salicylic acid, 3,5-di-
(Α, α-dimethylbenzyl) salicylic acid, 3- (α-
Methylbenzyl) -5- (α, α-dimethylbenzyl)
Salicylic acid, 4-methyl-5-cyclohexylsalicylic acid, 2-hydroxy-1-benzyl-3-naphthoic acid,
1-benzoyl-2-hydroxy-3-naphthoic acid, 3
-Hydroxy-5-cyclohexyl-2-naphthoic acid,
2-hydroxy-4-[(4-carboxy-5-hydroxy) phenyl] -1-naphthoic acid,

3-methyl-5- (iso) nonyl salicylic acid, 3-methyl-5- (iso) dodecyl salicylic acid, 3
-Methyl-5- (iso) pentadecylsalicylic acid, 3-
Methyl-5- (α-methylbenzyl) salicylic acid, 3-
Methyl-5- (α, α-dimethylbenzyl) salicylic acid, 3,5-di-sec-butylsalicylic acid, 3,5-di-t
ert-butyl-6-methylsalicylic acid, 3-tert-butyl-5-phenylsalicylic acid, 3,5-di-tert-amylsalicylic acid, 3-cyclotoxyl-5- (iso) nonylsalicylic acid, 3-phenyl-5- ( Iso) nonylsalicylic acid, 3- (α-methylbenzyl) -5- (iso) nonylsalicylic acid, 3-isopropyl-5- (iso) nonylsalicylic acid, 3- (iso) nonylsalicylic acid, 3-
(Iso) nonyl-5-methylsalicylic acid, 3- (iso)
Nonyl-5-cyclohexylsalicylic acid, 3- (iso)
Nonyl-5-phenylsalicylic acid, 3- (iso) nonyl-5- (α-methylbenzyl) salicylic acid, 3- (iso) nonyl-5- (4, α-dimethylbenzyl) salicylic acid, 3- (iso) nonyl- 5- (α, α-dimethylbenzyl) salicylic acid, 3- (α, α-dimethylbenzyl) -5- (iso) nonylsalicylic acid, 5- (iso) nonylsalicylic acid, 3- (iso) nonyl-6-methylsalicylic acid 3-tert-butyl-5- (iso) nonylsalicylic acid, 3,5-di (iso) nonylsalicylic acid,

3- (iso) dodecylsalicylic acid,
(Iso) dodecyl-5-methylsalicylic acid, 3- (iso) dodecyl-6-methylsalicylic acid, 3-isopropyl-5- (iso) dodecylsalicylic acid, 3- (iso) dodecyl-5-ethylsalicylic acid, 5- (iso ) Dodecyl salicylic acid, 3- (iso) pentadecyl salicylic acid, 3
-(Iso) pentadecyl-5-methylsalicylic acid, 3-
(Iso) pentadecyl-6-methylsalicylic acid, 5-
(Iso) pentadecylsalicylic acid, 3-cyclohexyl-5- (α-methylbenzyl) salicylic acid, 3-phenyl-5- (α-methylbenzyl) salicylic acid, 3- (α
-Methylbenzyl) salicylic acid, 3- (α-methylbenzyl) -5-methylsalicylic acid, 3- (α-methylbenzyl) -6-methylsalicylic acid, 3- (α-methylbenzyl) -5-phenylsalicylic acid, 3- (Α-methylbenzyl) -5-bromosalicylic acid, 3- (α, 4-dimethylbenzyl) -5-methylsalicylic acid, 3,5-di (α, 4-dimethylbenzyl) salicylic acid, 3- (α, α
-Dimethylbenzyl) -6-methylsalicylic acid, 3,5
-Di (α, α-dimethylbenzyl) salicylic acid, 5-
(4-mesitylmethylbenzyl) salicylic acid, benzylated styrenated salicylic acid, 2-hydroxy-3- (α,
Aromatic carboxylic acids such as α-dimethylbenzyl) -1-naphthoic acid or 3-hydroxy-7- (α, α-dimethylbenzyl) -2-naphthoic acid and polyvalent metal salts thereof are exemplified. Specific examples of polyvalent metals include magnesium, calcium, zinc, aluminum, iron, cobalt,
Nickel and the like can be mentioned. These may be used alone or as a mixture.

Incidentally, (iso) alkyl represents isoalkyl or normal alkyl. The isononyl group, isododecyl group and isopentadecyl group are each preferably a substituent formed by addition of propylene trimer, propylene tetramer or 1-butene trimer and propylene pentamer, respectively.

As pigments, in addition to calcium carbonate, for example, zinc oxide, magnesium oxide, titanium dioxide, aluminum hydroxide, kaolin, clay, calcined kaolin, delaminated kaolin, structured kaolin, magnesium sulfate, calcium sulfate, etc. Inorganic pigments and organic pigments (plastic pigments) such as polystyrene resin fine particles, urea formalin resin fine particles, and fine hollow particles are appropriately used as long as the effects of the present invention are not impaired.

As the binder, for example, starch, casein, gum arabic, carboxymethylcellulose, hydroxyethylcellulose, polyvinyl alcohol, carboxy-modified polyvinyl alcohol, styrene / butadiene copolymer latex, vinyl acetate latex and the like are blended. These can be used in combination with a modified polyvinyl alcohol containing silicon in the molecule. Incidentally, the pigment is usually contained in the color developing layer, 50 to 95% by weight of the total solid of the color developing layer, and the color developing agent is 1 to 1%.
It is preferable to mix 20% by weight and 1 to 40% by weight of a binder.

The method for preparing the coating solution for forming the color developing sheet is not particularly limited, and is appropriately prepared. For example, a method in which an organic developer is mechanically dispersed in water together with an inorganic pigment, a binder, a dispersant, and other additives, and a coating solution obtained by coating is applied to a support. The developer is dissolved in an organic solvent and emulsified in water, and after distilling off the organic solvent by a method such as steam distillation, a coating liquid obtained by adding an inorganic pigment, a binder and other additives is applied to a support. How to apply. Alternatively, a method of applying a coating solution in which both are mixed to a support is used.

As the organic solvent used for emulsifying and dispersing the color developer, halogenated hydrocarbons, aromatic hydrocarbons, esters, ketones, ethers, amides and nitriles having a boiling point of 200 ° C. or less are preferable. Among them, those having a solubility in water at room temperature of 5 or less are more preferable. Specific examples of the organic solvent include chloroform, methyl chloroform, benzene, toluene, xylene, chlorobenzene,
Examples include ethyl acetate, butyl acetate, isopropyl acetate, methyl ethyl ketone, methyl isobutyl ketone, dimethylacetamide and the like.

The water-soluble polymer used for emulsification includes polyvinyl alcohol, maleic anhydride-isobutylene copolymer, carboxymethyl cellulose, hydroxyethyl cellulose, polyacrylamide, polyacrylic acid, acrylamide-alkyl acrylate copolymer, ether Synthetic or natural polymers such as modified polyvinyl alcohol, polyvinylpyrrolidone, starch, casein, gum arabic, gelatin and the like can be mentioned.

In the present invention, the method for preparing the coating solution for the color developing layer is not particularly limited. Further, various assistants such as a water-proofing agent, a curing agent, a cross-linking agent, a defoaming agent, a coloring agent, a wetting agent, a flow modifier, and a preservative are appropriately added to the developing layer coating liquid as needed. You.

The coating solution for a color developing sheet thus prepared is
Normal coating such as air knife coater, blade coater, rod blade coater, roll coater, bar coater, size press coater, bill blade coater, curtain coater, short dwell coater, bar coater, etc. on supports such as paper, synthetic paper, film etc. It is applied by the device and finished as a color developing sheet for pressure-sensitive copying paper.

The coated amount of the support is not particularly limited 3 to 10 g / m ² by dry weight, preferably 4~7g / m ^2. The thus-obtained color-developed sheet for pressure-sensitive copying paper can be passed through an on or off super calender, a soft nip calender, or the like to be subjected to pressure smoothing.

[0039]

EXAMPLES Examples and comparative examples are described below to further clarify the effects of the present invention, but the present invention is not limited to these examples. In the examples, "parts" and "%" represent "parts by weight" and "% by weight", respectively, unless otherwise specified.

Example 1 [Preparation of coating solution for developing layer] 10 parts of zinc salt of 3,5-di (α-methylbenzyl) salicylic acid was added to 10 parts of toluene in 70 parts.
The mixture was dissolved at 30 ° C., and the toluene solution was emulsified in 30 parts of water containing 0.6 part of polyvinyl alcohol having a polymerization degree of 1700 and a saponification degree of 98% using a homomixer. An aqueous dispersion of coloring agent fine particles was obtained. This aqueous dispersion was mixed with light calcium carbonate (Tamapearl TP-1).
21; Okutama Kogyo Co., Ltd.), 90 parts, 100 parts of a 10% aqueous solution of modified polyvinyl alcohol containing silicon in the molecule were mixed, and 5 parts of dicyandiamide-diethylenetriamine polycondensate was further added to prepare a developing layer coating solution. .

[Production of a color developing sheet for pressure-sensitive copying paper]
The developing layer coating solution was applied to the surface of 0 g / m ² base paper with an air knife coater so that the dry coating amount was 6 g / m ² , and dried to obtain a color developing sheet for pressure-sensitive copying paper.

Example 2 A color developing sheet for pressure-sensitive copying paper was prepared in the same manner as in Example 1, except that 50 parts were mixed instead of 100 parts of a 10% aqueous solution of modified polyvinyl alcohol containing silicon in the molecule. I got

Example 3 A color developing sheet for pressure-sensitive copying paper was prepared in the same manner as in Example 1 except that 200 parts were mixed instead of 100 parts of a 10% aqueous solution of modified polyvinyl alcohol containing silicon in the molecule. I got

Example 4 A color developing sheet for pressure-sensitive copying paper was obtained in the same manner as in Example 1, except that 10 parts were added instead of 5 parts of dicyandiamide-diethylenetriamine polycondensate.

Example 5 Polycondensate of dicyandiamide-formalin (Neofix FY; manufactured by Nichika Chemical Co., Ltd.) was used instead of 5 parts of dicyandiamide-diethylenetriamine polycondensate in Example 1.
Was obtained in the same manner as in Example 1 except that 5 parts of was added.

Comparative Example 1 In Example 1, PVA-105 was used instead of 100 parts of a 10% aqueous solution of modified polyvinyl alcohol containing silicon.
A color developing sheet for pressure-sensitive copying paper was obtained in the same manner as in Example 1 except that 100 parts of a 10% aqueous solution (produced by Kuraray Co., Ltd.) was used.

Comparative Example 2 In the same manner as in Example 2 except that 50 parts of a 10% aqueous solution of PVA-105 (manufactured by Kuraray Co., Ltd.) was used instead of 50 parts of a 10% aqueous solution of modified polyvinyl alcohol containing silicon. Thus, a color developing sheet for pressure-sensitive copying paper was obtained.

Comparative Example 3 In Example 1, PVA-105 was used instead of 100 parts of a 10% aqueous solution of a modified polyvinyl alcohol containing silicon.
A color developing sheet for pressure-sensitive copying paper was obtained in the same manner as in Example 1 except that 200 parts of a 10% aqueous solution (produced by Kuraray Co., Ltd.) was used.

Comparative Example 4 In Example 4, PVA-105 was used instead of 100 parts of a 10% aqueous solution of modified polyvinyl alcohol containing silicon.
A color developing sheet for pressure-sensitive copying paper was obtained in the same manner as in Example 4 except that 100 parts of a 10% aqueous solution (manufactured by Kuraray Co., Ltd.) was used.

Comparative Example 5 In Example 5, PVA-105 was used instead of 100 parts of a 10% aqueous solution of modified polyvinyl alcohol containing silicon.
A color developing sheet for pressure-sensitive copying paper was obtained in the same manner as in Example 5 except that 100 parts of a 10% aqueous solution (manufactured by Kuraray Co., Ltd.) was used.

Comparative Example 6 In Example 1, PVA-105 was used instead of 100 parts of a 10% aqueous solution of modified polyvinyl alcohol containing silicon.
Developing sheet for pressure-sensitive copying paper in the same manner as in Example 1 except that 100 parts of a 10% aqueous solution (manufactured by Kuraray Co., Ltd.) was used and a developing layer coating solution was prepared without adding dicyandiamide-diethylenetriamine polycondensate. I got

Comparative Example 7 In place of 50 parts of a 10% aqueous solution of modified polyvinyl alcohol containing silicon in Example 2, 50 parts of a 10% aqueous solution of PVA-105 (manufactured by Kuraray Co., Ltd.) was used, and a dicyandiamide-diethylenetriamine polycondensate was used. A developer sheet for pressure-sensitive copying paper was obtained in the same manner as in Example 2 except that a developer coating solution was prepared without adding the developer.

Comparative Example 8 A color developing sheet for pressure-sensitive copying paper was obtained in the same manner as in Example 1 except that the coating solution for the color developing layer was prepared without adding the dicyandiamide-diethylene triamine polycondensate.

[Performance Comparison Test] An evaluation test was performed on the color-developed sheet for pressure-sensitive copying paper obtained as described above by the following method, and the results are shown in Table 1.

(1) Pressure Sensitive Copy Color Development A color developing sheet and a commercially available upper paper (KS copy / bright / black coloring, N-40 / Oji Paper) are overlapped so that the coated surfaces face each other, and the linear pressure is applied. Was passed through a super calendar set at 10 kg / cm to develop color, and after 1 hour, the color density was measured with a Macbeth densitometer RD-941.

(2) Desensitizing effect A commercially available desensitizing ink (desensitizing ink JEP6-3; manufactured by Oji Paper) was applied to the surface of the color developing sheet using a RI printing suitability tester (manufactured by Meiji Seisakusho). After printing, commercial paper (K
S copy / bright / black color, N-40 / Oji Paper)
Were superimposed so that the printing surface and the coating surface faced, and printing was performed with a typewriter. The amount of ink that did not completely develop color was measured by a gravimetric method.

(3) Surface Strength A commercially available printing ink (Tack Value 13; manufactured by Dainippon Ink) was printed three times on the developer application surface of a developer sheet using an RI printing suitability tester (manufactured by Meiji Seisakusho). And the state of powder falling was evaluated organoleptically according to the following five-level evaluation criteria. "Evaluation criteria" 5: No powder drop was observed. 4: Slight powder drop is observed. 3: Powder fall was observed, but there was no practical problem. 2: Powder fall was observed and there was a problem in practice. 1: Powder drop is remarkable.

[0058]

[Table 1]

[0059]

As is clear from Table 1, the color developing sheet for pressure-sensitive copying paper obtained in the examples of the present invention has a desensitizing effect even when the amount of desensitizing ink is small at the time of desensitizing printing. It was a developed color sheet for pressure-sensitive copying paper that developed and was excellent in color-forming properties, preservability and suitability for offset printing as pressure-sensitive copying paper.

Claims (1)

[Claims] 1. A color developing sheet for pressure-sensitive copying paper obtained by applying a coating solution containing a polyvalent metal salt of a nucleus-substituted aromatic carboxylic acid derivative and a pigment on a support and drying the coating solution. Contains at least one selected from dicyandiamide-formalin polycondensate and dicyandiamide-polyamine polycondensate in an amount of 1 to 10% by weight based on the total weight of the polyvalent metal salt of the nucleus-substituted aromatic carboxylic acid derivative and the pigment, A color developing sheet for pressure-sensitive copying paper, characterized by using a modified polyvinyl alcohol containing silicon in the molecule.