JPH0648018A - Manufacture of pressure-sensitive copying sheet - Google Patents

Abstract

PURPOSE:To obtain a high-quality pressure-sensitive copying sheet with satisfactory coloring properties and shorts contamination-free by adjusting a specific sheet so that specific conditions can be satisfied and further, adjusting a capsuled ink to specific viscosity. CONSTITUTION:A barrier layer is provided on one surface of an air-permeable sheet with a permeability of 35'' max based on JIS-P-8117 so that the permeability is 50''min. Next, an electron-receptive color developer coated layer is formed on the barrier layer. In addition, a microcapsuled ink which contains a microcapsule of an electron-donative coloring agent and has a viscosity of 15000cps (25 deg.C) max, is provided on the other surface using type printing or offset printing technique. The air-permeable sheet is such as acidic paper, neutral paper or synthetic paper obtained by using the fiber of natural pulp or synthetic pulp. If the permeability is 35''min, the permeable sheet has inferior coloring properties. If the permeability of the barrier layer is not higher than 50'', the sheet shows a higher rate of shorts contamination. If the viscosity is 15000cps min, the sheet indicates inferior coloring properties.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a pressure-sensitive copying paper having an electron-accepting color developer layer on one side of a support and an electron-donating color developer layer on the opposite side.

[0002]

2. Description of the Related Art Electron-donating color formers such as crystal violet lactone and benzoyl leuco methylene blue,
Pressure-sensitive copying paper utilizing the principle of developing color by reaction with an electron-accepting color developer such as activated clay, phenolic resin, and polyvalent metal salt of salicylic acid derivative is well known.

Generally, such a pressure-sensitive copying paper is produced by a phase separation method,
Top paper on which the color-forming agent-encapsulating microcapsules prepared by a method such as an interfacial polymerization method or an in-situ method is provided on the back surface of the support, bottom paper on which the developer is provided on the support, the microcapsules and the developer. Practical papers, in which the sheets are provided on different surfaces of the support, are appropriately combined and used. The capsule layer of such pressure-sensitive copying paper is usually formed by applying an aqueous capsule coating liquid to a support with a large coating machine (hereinafter referred to as a coating method). As a special manufacturing method, there is a method of converting the capsule into an ink and coating it on a support with a printing machine (hereinafter referred to as a printing method).

The printing method is suitable for the production of a large number of products in a small amount as compared with the coating method because it can produce even a small lot in a small amount of loss, and for example, it is a pressure sensitive pressure of a special coloring color which tends to be small in a lot. Suitable for producing copy paper.
In addition, the printing method is more economical than the coating method in which expensive capsules are applied to the entire surface of the support because the capsules can be partially printed only on the necessary portions of the support. Further, the printing method is such that the upper surface of the high-quality paper or the back surface of the lower paper is partially printed with capsule inks having different coloring tones, or the upper paper or the entire surface coated by the coating method as described in JP-A-1-301360. Various printing such as pressure-sensitive copying paper (upper paper or middle paper) having a plurality of color-developing color tones can be obtained by partially printing a capsule ink having a color-developing color different from that of the capsule on the coated surface of the medium paper. It is possible to produce varieties with characteristics.

As described above, the printing method is a production method having many merits, but it cannot be said to be sufficient in terms of quality as a pressure-sensitive copying paper. That is, when an inner sheet is made by printing capsule ink on the back surface of a sheet provided with a developer layer on one side of a breathable support such as high-quality paper, it is damaged by printing pressure. The color developer released from the capsules passes through the paper layer and reaches the developer layer on the back surface to form colored stains (hereinafter referred to as short stains).
Has a problem that is likely to occur.

It is effective for the present inventors to use a support having an air permeability of 40 seconds or more as a means for solving such a problem. Above all, in view of the effect, a binder is size-pressed or coated to form a barrier property. It was found that it is preferable to use a sheet provided with the above, and it was previously proposed (JP-A-1-264888). However, as a result of further research, when a letterpress type ink or an offset type ink is used as the capsule ink, a copy paper having a poor coloring property cannot be obtained by simply using a support having an air permeability of 40 seconds or more. It turns out that there is a new adverse effect that only this can be obtained.

[0007]

DISCLOSURE OF THE INVENTION As a result of intensive studies to solve such a problem, the inventors of the present invention adjusted a sheet having specific conditions to satisfy specific conditions,
In addition, by adjusting the capsule ink used for letterpress printing or offset printing to a specific viscosity and using it, it is possible to obtain high-quality pressure-sensitive copying paper that has good color development that could not be achieved until now and is free from short-circuit stains. After finding out that, the present invention was finally completed.

[0008]

The present invention is based on JIS P
Based on 8117, a breathable sheet having an air permeability of 35 seconds or less is provided with a barrier layer so that the air permeability is 50 seconds or more, and then an electron-accepting developer coating layer is provided on the barrier layer. Production of pressure-sensitive copying paper characterized in that microcapsule ink containing an electron-donating color-forming agent-encapsulating microcapsule on the other side and having a viscosity of 15,000 cps (25 ° C.) or less is provided by letterpress printing or offset printing. Is the way.

[0009]

When the capsule ink is subjected to letterpress printing or offset printing, the ink generally has a high viscosity, so that the ink medium is hardened on the surface of the support in a large amount. It is presumed that the oil release property deteriorates and the color development property deteriorates.
It has been found that the color development is improved by using a breathable sheet having an air permeability of 35 seconds or less, which is not used in ordinary pressure-sensitive copying paper, based on 17. By the way, when a sheet having an air permeability of more than 35 seconds is used, the ink medium of the capsule ink does not penetrate into the sheet and remains on the surface to be cured, so that the oil release property from the capsule is poor. Therefore, only copy paper with poor color development can be obtained. The air-permeable sheet used in the present invention has a value of air permeability according to JIS P8117 among sheets of acidic paper, neutral paper, synthetic paper and the like obtained by making fibers of natural pulp or synthetic pulp. Three
Examples include those of 5 seconds or less. Above all, the air permeability is 5 to 25
The range of seconds is preferable.

The present invention uses such a breathable sheet, which is provided with a barrier layer on one side so that the air permeability is 50 seconds or more. If the air permeability is less than 50 seconds, only the short-circuited dirt is inferior. The coating liquid used for forming the barrier layer is basically prepared by using a material having a film-forming property such as a water-soluble polymer or latex as a component.

Examples of the water-soluble polymer include starch, casein, sodium alginate, gum arabic, phosphorylated starch,
Oxidized starch, carboxymethyl cellulose, sodium polyacrylate, polyvinyl alcohol, hydroxyethyl cellulose, polyvinylpyrrolidone, polyacrylic acid amide, methyl vinyl ether-maleic anhydride copolymer,
Ethylene-maleic anhydride copolymer, vinyl acetate-maleic anhydride copolymer, styrene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, methacrylamide-maleic anhydride copolymer, methyl acrylate -Acrylic acid copolymer, ethyl acrylate-acrylic acid copolymer, methyl acrylate-methacrylic acid copolymer, methyl methacrylate-acrylic acid copolymer, methyl methacrylate-methacrylic acid copolymer, methyl acrylate -Acrylamide-acrylic acid copolymer, acrylonitrile-acrylic acid copolymer, acrylonitrile-methacrylic acid copolymer, hydroxyethyl acrylate-acrylic acid copolymer, hydroxyethyl acrylate-methacrylic acid copolymer, vinyl acetate-acrylic acid Copolymer, vinyl acetate-methacrylate Acid copolymer, acrylamide-acrylic acid copolymer, acrylamide-methacrylic acid copolymer, methacrylamide-acrylic acid copolymer, methacrylamide-methacrylic acid copolymer, vinyl acetate-crotonic acid copolymer, vinyl acetate -Acrylic acid-maleic acid copolymer, vinyl acetate-methacrylic acid-maleic acid copolymer, vinyl acetate-ethyl acrylate-maleic acid copolymer, methyl acrylate-vinylbenzene sulfonic acid copolymer, vinyl acetate- Examples thereof include vinylbenzene sulfonic acid copolymer. These are used alone or in combination. Among the water-soluble polymers, anionic ones can also be used as metal salts or ammonium salts.

Examples of the latex include styrene-butadiene latex, acrylonitrile-butadiene latex, acrylic latex, vinyl acetate latex and carboxy-modified latex thereof. These are used alone or in combination. Of these, the combined use of a water-soluble polymer and a latex is particularly preferable because it has an excellent effect of preventing short-circuiting stains and has excellent coatability.

In addition to the above film-forming materials, the barrier layer coating liquid may include, if necessary, light calcium carbonate, heavy calcium carbonate, aluminum hydroxide, zinc oxide, titanium oxide, calcium sulfate, silica, kaolin, calcined kaolin. , White pigments such as satin white, tilting materials such as starch particles or pulp powder, oil capsules acting as color sensitizers, dispersants, surfactants, defoamers, thickeners, preservatives, release agents, Optical brightener, ultraviolet absorber, antioxidant,
Various auxiliaries such as colored dyes are added and mixed under stirring, and usually prepared as an aqueous coating liquid. The components other than the film-forming material are usually added so as to be 75% by weight or less of the coating solid content.

The coating liquid thus prepared is usually coated with various coating machines such as an air knife coater, a bar coater, a roll coater, a blade coater, a gravure coater and a curtain coater so that the air permeability of one surface of the breathable sheet is 50 seconds or more. Is smeared on. Materials that coating amount of time is being used for the coating liquid, formulation, it can not be said unconditionally depends coating method or the like, usually 1 to 30 g / m ^2, preferably a binder component is 0.5 to 8 g / m ² It is smeared so that it becomes the range of. The smeared sheet is subjected to a super calendering process if necessary.

The present invention provides an electron-accepting developer layer on the barrier layer thus obtained. If a color developer layer is provided on the support surface side of the back surface of the barrier layer, and the capsule ink layer is provided on the barrier layer, the ink medium of the capsule ink becomes difficult to penetrate, resulting in extremely poor color developability.

Examples of the electron-accepting developer include clays such as acid clay and activated clay, phenol resins, and Japanese Patent Publication No.
Polyvalent metal salts of various aromatic carboxylic acids described in 1-25174, 2,2-described in JP-A-54-106316
Materials known in the art, such as a zinc salt of a bisphenol sulfone compound, can be used alone or in combination.

The coating liquid containing the electron-accepting developer includes, in addition to the above-mentioned electron-accepting developer, a water-soluble polymer or latex binder as described above, and if necessary, a white pigment and starch as described above. Stilt materials such as particles or pulp powder, oil capsules that act as color sensitizers, dispersants, surfactants, defoamers, thickeners, preservatives, release agents, optical brighteners, ultraviolet absorbers, It is prepared as an aqueous coating liquid by adding various additives such as an antioxidant and a colored dye under agitation and mixing. Above all, the addition of oil capsules is particularly preferable because a copy paper having good color development can be obtained.

Usually, the electron-accepting color developer has a coating solid content of 2%.
-80% by weight, and the binder is blended in the range of 5-40% by weight. The white pigment is blended in the range of 0 to 90% by weight, and the oil capsule is blended in the range of 0 to 40% by weight.

The coating solution thus prepared is usually coated on the barrier layer with various coating machines such as an air knife coater, a bar coater, a roll coater, a blade coater, a gravure coater and a curtain coater.
² , preferably in the range of 3 to 10 g / m ² .
The smeared sheet is subjected to a super calendering process if necessary.

On the other hand, electron-donating color formers used in capsule inks are known in the art, for example, 3,3-bis (p-dimethylaminophenyl) -6-.
Dimethylaminophthalide, 3- (p-dimethylaminophenyl) -3- (1,2-dimethylindol-3-yl) phthalide, 3,3-bis (1,2-dimethylindol-3-yl) -5 -Dimethylaminophthalide, 3,
3-bis (9-ethylcarbazol-3-yl) -6-
Triallylmethane dyes such as dimethylaminophthalide,
4,4-bis-dimethylaminobenzhydrylbenzyl ether, N-halophenyl leuco auramine, N-
Diphenylmethane dyes such as 2,4,5-trichlorophenylleuco auramine, benzoyl leuco methylene blue, thiazine dyes such as P-nitrobenzoyl leuco methylene blue, 3-methyl-spiro-dinaphthopyran, 3-phenyl-spiro-dinaphthopyran, 3 -Spiro dyes such as propyl-spiro-dibenzopyran, lactam dyes such as rhodamine-B-anilinolactam and rhodamine (o-chloroanilino) lactam, 3-dimethylamino-7-methoxyfluorane, 3-diethylamino-6 -Methyl-7-chlorofluorane, 3- (N-ethyl-p-toluidino) -7-methylfluorane, 3-
Diethylamino-7-N-methylaminofluorane, 3
-Diethylamino-7-dibenzylaminofluorane,
3- (N-ethyl-p-toluidino) -6-methyl-7
-Phenylaminofluorane, 3-diethylamino-6
-Methyl-7-phenylaminofluorane, 3- (N-
Cyclohexyl-N-methylamino) -6-methyl-7
Fluorane dyes such as -phenylaminofluorane, 3-piperidino-methyl-7-phenylaminofluorane, 3-diethylamino-6-methyl-7-xylidinofluorane, 3,3-bis [2- (p- Dimethylaminophenyl) -2- (p-methoxyphenyl) ethylene-2
-Yl] -4,5,6,7-tetrachlorophthalide and other infrared region absorbing dyes, etc., which may be used alone or in combination.

The above-mentioned electron-donating color former is usually encapsulated in a state of being dissolved in oil, and examples of such oil include the following substances known in the art.
Vegetable oils such as cottonseed oil; mineral oils such as kerosene, paraffin, naphthene oil and chlorinated paraffin; aromatic hydrocarbons such as alkylated biphenyl, alkylated terphenyl, alkylated naphthalene, diarylethane, triarylmethane, diphenylalkane Kinds; esters such as dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate, dioctyl phthalate, diethyl adipate, propyl adipate, di-n-butyl adipate, dioctyl adipate, and the like, and mixtures thereof.
The electron-donating color former is usually added in an amount of 2 to 80 parts by weight, preferably 5 to 50 parts by weight, based on 100 parts by weight of oil.

As the encapsulation method, a known coacervation method, interfacial polymerization method, in-situ method or the like can be appropriately selected and used. Among them, a melamine-formalin resin film obtained by the in-situ method is used. Capsules are particularly preferable because they have excellent solvent resistance and are easy to be powdered. The average particle size of the capsule varies depending on the film material used or the film thickness and cannot be generally stated, but it is usually 1 to 1
It is 0 μm. Further, the capsule may contain an antioxidant and an ultraviolet absorber, if necessary.

The aqueous capsule dispersion obtained by the above method is untreated or filtered, for example, dried by aeration,
Surface drying, fluidized drying, air stream drying, spray drying, vacuum drying,
Freeze-drying, infrared-drying, high-frequency drying, ultrasonic drying, fine pulverization, etc. are processed into powder capsules, which are then dispersed in the ink medium, and various auxiliary agents are added as necessary to prepare capsule inks. It Further, a cake-like material obtained by filtering the aqueous capsule dispersion liquid is mixed with an ink medium, and various auxiliaries are further added, if necessary, to prepare a capsule ink. Further, the cake-like material obtained by filtering the aqueous capsule dispersion is mixed with the ink medium, water contained therein is removed under reduced pressure, and various auxiliaries are added as necessary to prepare a capsule ink.

As a device used for mixing or dissolving the capsules and various auxiliary agents in the ink medium, those known in the ink industry can be used, and among them, a high speed stirrer such as Corless and a roll mill are preferably used. Examples of the ink medium used for the letterpress type or offset type capsule ink include various media known in the ink industry,
For example, a high boiling point medium is used in the case of permeation drying type ink, oils are used in the case of oxidation polymerization type ink, and a compound having at least one vinyl group or vinylidene group in the molecule is used in the case of ultraviolet curing ink.

Examples of the high boiling point medium used in the permeation-drying type ink include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, 2,3-butylene glycol, methyl cellosolve,
Cellosolve, butyl cellosolve, carbitol, butyl carbitol and the like can be mentioned.

When a high boiling medium is used, a resin for fixing the capsule to the support is usually used. Examples of the resin include gum rosin, wood rosin, shellac, ester gum, pentaerythritol ester of rosin, pentaerythritol ester of polymerized rosin, maleic acid resin, pentaerythritol ester of maleated rosin, dimerized rosin, rosin-modified phenolic resin, butanol-modified Urea resin, butanol modified melamine resin, terpene resin, terpene phenol resin, soybean oil modified alkyd resin, polyamide resin, polyvinyl acetate,
Acrylic resin, vinyl chloride, vinyl chloride / vinyl acetate copolymer, ethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, methyl vinyl ether-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer Examples include coalesce, modified polyvinyl alcohol, polyvinyl butyral, polyvinyl pyrrolidone, ethyl cellulose, nitrocellulose, hydroxypropyl cellulose, cellulose acetate propionate, cellulose acetate butyrate and the like.

In the case of the permeation-drying type ink, in addition to the above-mentioned high boiling point medium and resin, cellulose powder, starch particles, synthetic resin particles and other stilt materials, desensitizers and other desensitizing components for color development may be used as required. White pigments such as titanium oxide and surface-treated titanium oxide, ultraviolet absorbers, antioxidants, optical brighteners, plasticizers, coloring dyes, thixotropy imparting agents, and the like can be added.

The capsule content in the capsule ink is usually adjusted to 5 to 50 parts by weight with respect to 100 parts by weight of the ink. Also, the content of the ink medium is 1
It is prepared in the range of 30 to 90 parts by weight with respect to 00 parts by weight. Examples of oils used as a medium for the oxidation polymerization type ink include vegetable oils such as linseed oil, safflower oil, soybean oil and castor oil: dehydrated castor oil, polymerized oil, maleated oil,
Processing oils such as vinyl oil and urethane oil: machine oil, mineral oil such as spindle oil, and the like.

In the case of the oxidative polymerization type ink, in addition to the above oils, if necessary, a tilting material such as cellulose powder, starch particles, synthetic resin particles, a desensitizing component for color development such as a desensitizing agent, titanium oxide, Add white pigment such as surface treated titanium oxide, UV absorber, antioxidant, fluorescent whitening agent, plasticizer, coloring dye, thixotropic agent, solvent, wax, dryer, thickener, gelling agent, etc. You can

The capsule content in the capsule ink is usually adjusted to the range of 5 to 50 parts by weight with respect to 100 parts by weight of the ink. Also, the content of the ink medium is 1
It is prepared in the range of 30 to 90 parts by weight with respect to 00 parts by weight. Examples of the compound having one or more vinyl groups or vinylidene groups in the molecule used as the medium of the ultraviolet curable ink, for example, acryloyl group, methacryloyl group, allyl group, unsaturated polyester, vinyloxy, a polyol having an acrylamide group, Examples thereof include reaction products of polyamines or amino alcohols with unsaturated carboxylic acids, reaction products of hydroxyl group-containing acrylates or methacrylates with polyisocyanates, and the like. Representative compounds include, for example, polyethylene glycol diacrylate, propylene glycol dimethacrylate, pentaerythritol triacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, hexanediol diacrylate, 1,2-
Butanediol diacrylate, reaction product of epoxy resin and acrylic acid, reaction product of pentaerythritol and methacrylic acid, acrylic acid, reaction product of diethylene glycol and maleic acid, acrylic acid, methyl methacrylate, butyl methacrylate, styrene, etc. To be

When the above compound is used, it is necessary to add a photopolymerization initiator at the same time, and a sensitizer may be added if necessary. Examples of the photopolymerization initiator include benzoquinone, phenanthrenequinone, naphthoquinone,
Aromatic ketones such as diisopropylphenanthrenequinone, benzoisobutyl ether, benzoin, furoin butyl ether, Michler's ketone, Michler's thioketone, fluorenone, trinitrofluorenone, β-benzoylaminonaphthalene, quinone compounds, ether compounds,
A nitro compound is mentioned.

Examples of the sensitizer include triethanolamine, N-methyldiethanolamine, N, N-dimethylethanolamine, N-methylmorpholine and the like. In the case of UV curable ink, in addition to the above, cellulose powder, starch particles, synthetic resin particles and other tilting materials, desensitizing components such as desensitizing components for color development, titanium oxide, surface treated titanium oxide, etc. White pigments, antioxidants, optical brighteners, plasticizers, coloring dyes, thixotropic agents,
Thickeners, resins, oils, high boiling point media, waxes, dryers, thickeners, gelling agents and the like can be added.

The capsule content in the capsule ink is usually adjusted to the range of 5 to 50 parts by weight with respect to 100 parts by weight of the ink. Also, the content of the ink medium is 1
It is prepared in the range of 30 to 90 parts by weight with respect to 00 parts by weight. An ultraviolet irradiation device such as a high pressure mercury lamp is usually used for drying the ink.

According to the present invention, the B of the permeation-drying type, the oxidative-polymerizing type, and the ultraviolet-curing type capsule ink thus obtained is used.
Viscosity measured by a viscometer (60 rpm, 25 ° C) is 150
What was prepared so that it might become 00 cps or less is used. By using an ink having such a viscosity and printing on the non-coated surface of a sheet satisfying the above-mentioned specific conditions, it is possible to obtain a pressure-sensitive copying paper in which excellent color developability and short-circuit stains do not occur. Incidentally, the viscosity of the ink is more preferably 8000 cps or less. In addition, 15
When an ink having a viscosity exceeding 000 cps is used, the color developability is inferior even when printed on a sheet satisfying the above specific conditions.

The prepared permeation-drying type, oxidation-polymerizing type, and ultraviolet-curing type capsule inks have a dry weight of usually 2 to 2 on the opposite side of the barrier layer of the sheet by letterpress or offset printing.
10 g / m ^2, is applied preferably to be in the range of 3 to 6 g / m ^2. The middle paper of the present invention thus obtained is used in suitable combination with pressure-sensitive copying paper such as upper paper, middle paper, and lower paper.

[0036]

EXAMPLES Examples and comparative examples will be given below in order to further clarify the effect 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 Barrier Layer Coated Paper) Light Calcium Carbonate 100
Parts are dispersed in 100 parts of 0.2% aqueous sodium polyacrylate solution, and further 50 parts of gelatinized starch (solid content) and a water-soluble acrylic polymer (trade name: CP-547, manufactured by Sanyo Kasei Co., Ltd.) 2
A 30 wt% coating liquid for barrier layer was obtained by adding 0 parts (solid content) and 30 parts (solid content) of carboxy-modified styrene-butadiene latex under stirring and then diluting. This coating liquid is applied to a 40 g / m ² base paper having an air permeability of 13 seconds according to JIS P8117 with an air knife coater so that the dry weight is 8 g / m ^2, and a barrier layer having an air permeability of 70 seconds is applied. Got the paper.

(Preparation of Oil Capsule) Ethylene-maleic anhydride copolymer (trade name: adjusted to pH 6.0)
After emulsifying 100 parts of alkyldiphenylethane as an internal phase oil in 200 parts of a 3% aqueous solution of EMA-31, manufactured by Monsanto Co., Ltd., this system was heated to 55 ° C. Separately, add 15 parts of melamine to 45 parts of 37% formaldehyde aqueous solution,
An aqueous prepolymer solution was prepared by reacting at 60 ° C. for 15 minutes. This prepolymer aqueous solution was added dropwise to the emulsion, 0.1N hydrochloric acid was added dropwise with stirring to adjust the pH to 5.3, the system was heated to 80 ° C. and stirred for 1 hour. Then, 0.2N hydrochloric acid was added dropwise to lower the pH to 3.5, and the mixture was stirred for 3 hours and then cooled to obtain a dispersion liquid of oil capsules having an average particle diameter of 4.5 μm.

(Preparation of color developing sheet) 60 parts of light calcium carbonate, 10 parts of zinc oxide, a mixture of zinc 3,5-di (α-methylbenzyl) salicylate and α-methylstyrene-styrene copolymer ( Mixing ratio 80/20) 10 parts, oil capsule 10 parts, pulp powder 10 parts 0.2 parts
% Polyvinyl alcohol aqueous solution, and further dispersed with 10 parts of gelatinized starch (solid content) and carboxy-modified styrene.
30 parts by weight of a developer coating solution obtained by diluting 15 parts (solid content) of butadiene latex, 1 part of carboxymethyl cellulose and 1 part of hydroxyethyl cellulose under stirring and then diluting the solution was dried on the barrier layer of the coated paper. Weight is 7g
/ M ² was smeared with an air knife coater to obtain a color-developing sheet.

(Preparation of Capsule Ink) 25 parts of 3,3-bis (2-methyl-1-octyl-3-indolyl) phthalide was dissolved by heating in 75 parts of benzyltoluene to obtain an internal phase oil. Subsequently, EMA-3 whose pH was adjusted to 6.0
After emulsifying the internal phase oil in 200 parts of a 3% aqueous solution of 1, the system was heated to 55 ° C. Separately, 15 parts of melamine was added to 45 parts of 37% aqueous formaldehyde solution, and the mixture was reacted at 60 ° C. for 15 minutes to prepare a prepolymer aqueous solution. This prepolymer aqueous solution was added dropwise to the emulsion, and 0.1N hydrochloric acid was added dropwise with stirring to adjust the pH to 5.3.
The system is heated to 80 ° C. and stirred for 1 hour, then 0.2 N
Hydrochloric acid was added dropwise to lower the pH to 3.5, and the mixture was stirred for 3 hours and then cooled to obtain a dispersion liquid of capsules having an average particle diameter of 3.0 μm.

Next, this dispersion was filter-pressed, and subsequently 20 parts of this capsule (solid content), 2 parts of benzoin methyl ether, 0.3 part of triethanolamine and 1 part of colloidal silica were mixed with an ethylenically unsaturated compound (60 parts).
(0 cps, 25 ° C.) 77 parts of a high-speed stirrer (Choles) was used to mix and disperse the mixture, and then water was removed under reduced pressure, followed by mixing using a three-roll mill to give a viscosity of 5000 cps.
An ink of (25 ° C.) was obtained.

(Preparation and Evaluation of Medium Paper) The above-mentioned capsule ink is letterpress-printed (ink amount 5.0 g / m ² ) on the base paper surface of the above-mentioned color developing sheet, and the ink is cured by using a 6 kw high pressure mercury lamp. I got the inside paper. No short stain was found on the obtained middle paper. When two sheets of medium paper were overlaid and printed with a typewriter, a very good color image was obtained.

Example 2 (Preparation of Barrier Layer Coated Paper) Obtained in the same manner as in Example 1.
Apply a barrier layer coating liquid of 40 g / m with an air permeability of 22 seconds. ²original
3g / m dry weight on paper²To be an air knife
Coat with a coater and apply a barrier layer coated paper with air permeability of 72 seconds.
Obtained.

(Preparation of developer sheet) The developer coating solution obtained in the same manner as in Example 1 was spread on the barrier layer of the coated paper with an air knife coater so that the dry weight was 7 g / m ^2. Then, a color developing sheet was obtained.

(Preparation and Evaluation of Medium Paper) Capsule ink obtained in the same manner as in Example 1 was letterpress-printed (ink amount 5.0 g / m ² ) on the base paper surface of the color developing sheet, and 6 kw of high pressure mercury was used. The ink was cured using a lamp to obtain a medium paper.
No short stain was found on the obtained middle paper. When two sheets of medium paper were overlaid and printed with a typewriter, a very good color image was obtained.

Example 3 (Preparation of Barrier Layer Coated Paper) Obtained in the same manner as in Example 1.
Apply a barrier layer coating liquid of 40 g / m with an air permeability of 30 seconds ²original
2 g / m dry weight on paper²To be an air knife
Coat with a coater and apply a barrier layer coated paper with an air permeability of 68 seconds.
Obtained. (Preparation of color development sheet) On the barrier layer of the coated paper,
The developer coating solution obtained in the same manner as in Example 1 had a dry weight of 7 g /
m²Smear with an air knife coater to develop color
Got the sheet.

(Preparation and Evaluation of Medium Paper) Capsule ink obtained in the same manner as in Example 1 was letterpress-printed (ink amount 5.0 g / m ² ) on the base paper surface of the color developing sheet, and 6 kw of high-pressure mercury was used. The ink was cured using a lamp to obtain a medium paper.
No short stain was found on the obtained middle paper. When two sheets of medium paper were overlaid and printed with a typewriter, a good color image was obtained. However, it was inferior to Example 1.

Example 4 (Preparation of Capsule Ink) The capsule dispersion obtained in the same manner as in Example 1 was filter-pressed, followed by 20 parts (solid content) of this capsule, 2 parts of benzoin methyl ether and 0 of triethanolamine. .3 parts and 1 part of colloidal silica are ethylenically unsaturated compounds (2600 cps, 25 ° C)
77 parts were mixed and dispersed using a high-speed stirrer (Choleth), water was removed under reduced pressure, and then the mixture was mixed using a three-roll mill to obtain an ink having a viscosity of 12000 cps (25 ° C.).

(Preparation and Evaluation of Medium Paper) On the base paper surface of the color developing sheet obtained in the same manner as in Example 1, the above capsule ink was letterpress-printed (ink amount 5.0 g / m ² ), and 6 kw of high pressure mercury was used. The ink was cured using a lamp to obtain a medium paper.
No short-circuited stain was found on the obtained sheet. When two sheets of medium paper were overlaid and printed with a typewriter, a good color image was obtained. However, it was inferior to Example 1.

Example 5 (Preparation of Barrier Layer Coated Paper) Obtained in the same manner as in Example 1.
Apply a barrier layer coating liquid of 40 g / m with an air permeability of 13 seconds. ²original
4g / m dry weight on paper²So that the air knife
To obtain a barrier layer coated paper with an air permeability of 55 seconds.
It was (Preparation of color development sheet) On the barrier layer of the coated paper,
The developer coating solution obtained in the same manner as in Example 1 had a dry weight of 7 g /
m²Smear with an air knife coater to develop color
Got the sheet.

(Preparation and Evaluation of Medium Paper) Capsule ink obtained in the same manner as in Example 1 was letterpress-printed (ink amount 5.0 g / m ² ) on the base paper surface of the above-mentioned color developing sheet, and a high pressure of 6 kw was applied. The ink was cured using a mercury lamp to obtain a medium paper. Almost no short stain was found on the obtained middle paper. However, it was slightly inferior to Example 1. When two sheets of medium paper were overlaid and printed with a typewriter, a very good color image was obtained.

Example 6 Capsule ink obtained in the same manner as in Example 1 was offset-printed (ink amount 4.1 g / m ² ) on the base paper surface of the color developing sheet obtained in the same manner as in Example 1 to give 6 kw. The ink was cured using the high pressure mercury lamp of No. 2 to obtain a medium paper. No occurrence of short stain was observed on the obtained sheet. When two sheets of medium paper were overlaid and printed with a typewriter, a very good color image was obtained.

Comparative Example 1 (Preparation of Barrier Layer Coated Paper) Obtained in the same manner as in Example 1.
Coating liquid for barrier layer with air permeability of 40 seconds 40g / m ²original
2 g / m dry weight on paper²So that the air knife
To obtain a barrier layer coated paper with an air permeability of 79 seconds.
It was

(Preparation of developer sheet) The developer coating solution obtained in the same manner as in Example 1 was spread on the barrier layer of the coated paper with an air knife coater so that the dry weight was 7 g / m ^2. Then, a color developing sheet was obtained.

(Preparation and Evaluation of Medium Paper) Capsule ink obtained in the same manner as in Example 1 was letterpress-printed (ink amount 5.0 g / m ² ) on the base paper surface of the above-mentioned color developing sheet, and 6 kw of high pressure mercury was used. The ink was cured using a lamp to obtain a medium paper.
No short stain was found on the obtained middle paper. When two sheets of medium paper were overlaid and printed with a typewriter, the color image obtained was considerably inferior.

Comparative Example 2 (Preparation of Barrier Layer Coated Paper) Obtained in the same manner as in Example 1.
Apply a barrier layer coating liquid of 40 g / m with an air permeability of 13 seconds. ²original
2 g / m dry weight on paper²So that the air knife
To obtain a barrier layer coated paper with air permeability of 42 seconds.
It was (Preparation of color development sheet) On the barrier layer of the coated paper,
The developer coating solution obtained in the same manner as in Example 1 had a dry weight of 7 g /
m²Smear with an air knife coater to develop color
Got the sheet. (Creation and evaluation of medium paper) On the base paper surface of the color development sheet,
Letterpress printing of the capsule ink obtained in the same manner as in Example 1
(Ink amount 5.0g / m²), 6kw high pressure mercury run
Was used to harden the ink to obtain medium-sized paper.
Occurrence of short dirt was observed.

Comparative Example 3 (Preparation of Capsule Ink) The capsule dispersion obtained in the same manner as in Example 1 was filter-pressed, followed by 20 parts of this capsule (solid content), 2 parts of benzoin methyl ether and 0 of triethanolamine. .3 parts and 1 part of colloidal silica are ethylenically unsaturated compounds (5300 cps, 25 ° C)
77 parts were mixed and dispersed using a high-speed stirrer (Choleth), water was removed under reduced pressure, and then the mixture was mixed using a three-roll mill to obtain an ink having a viscosity of 20000 cps (25 ° C.).

(Preparation and Evaluation of Medium Paper) The above capsule ink was typographically printed (ink amount 5.0 g / m ² ) on the base paper surface of the color developing sheet obtained in the same manner as in Example 1, and a high pressure mercury lamp of 6 kw was used. Was used to cure the ink to obtain a medium paper. No short stain was found on the obtained middle paper. Also, two sheets of medium paper were overlaid and printed with a typewriter, but the color image obtained was extremely inferior.

Comparative Example 4 Capsule ink obtained in the same manner as in Example 1 was offset-printed (ink amount of 4.2 g / m ² ) on the base paper surface of the color-developing sheet obtained in the same manner as in Comparative Example 1 to obtain 6 kw. The ink was cured using the high pressure mercury lamp of No. 2 to obtain a medium paper. No short stain was found on the obtained middle paper. Also, two sheets of medium paper were overlaid and printed with a typewriter, but the color image obtained was extremely inferior.

[0060]

As described above, according to the present invention, a pressure-sensitive copying paper which does not cause short-circuiting stains even when the capsule ink is letterpress-printed or offset-printed and is excellent in color developability can be obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shunsuke Shioi 4-3-1 Jōkoji, Amagasaki City, Hyogo Prefecture Kanzaki Paper Co., Ltd. Kanzaki Mill

Claims (1)

[Claims] 1. An air permeability of 3 according to JIS P 8117.
A barrier layer is provided on one surface of the breathable sheet for 5 seconds or less so that the air permeability is 50 seconds or more, then an electron-accepting developer coating layer is provided on the barrier layer, and the electron-donating property is provided on the other surface. Contains color-forming agent-encapsulating microcapsules, 15,000 cp
A method for producing pressure-sensitive copying paper, characterized in that a microcapsule ink having a viscosity of s (25 ° C.) or less is provided by letterpress printing or offset printing.