JPH05171088A - Capsular ink composition - Google Patents

Abstract

PURPOSE:To obtain a capsular ink composition which can give a high-quality capsule-coated sheet by using a specified compound as an ethylenically unsaturated compound. CONSTITUTION:A UV-curable capsular ink composition consisting essentially of microcapsules, an ethylenically unsaturated compound and a photopolymerization initiator, wherein the ethylenically unsaturated compound comprises a liquid polybutadiene acrylate and/or a liquid hydrogenated 1,2-polybutadiene acrylate. The above composition can give a high-quality capsule-coated sheet which has not heretofore been realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capsule ink composition, and more particularly to a UV curable capsule ink composition.

[0002]

2. Description of the Related Art Microcapsules are usually several μm to several 1
It has a particle size of 0 μm and is used as an internal phase for medicines, pesticides, fragrances,
Dyes, liquid crystals, finger temperature materials, adhesives, etc. are covered with natural or synthetic polymer films, and they also have the advantage of chemically or physically protecting internal phase substances and handling liquids as solids. It is widely used in a wide range of fields including pressure-sensitive copying paper.

Generally, as pressure-sensitive copying paper, an electron-donating color former such as crystal violet lactone or benzoyl leuco methylene blue, and an electron-accepting developer such as activated clay, phenol resin or a polyvalent metal salt of salicylic acid derivative are used. It is well known that the principle of developing a color by a reaction is used, and a phase separation method, an interfacial polymerization method, in-situ
Top paper coated with color-forming agent-encapsulated microcapsules prepared by a method such as a method on the back surface of the support, bottom paper coated with a color developer on the surface of the support, and the microcapsules and the color developer separately on the support The medium paper applied to the surface of is properly put together for practical use.

Separately, a so-called single pressure-sensitive copying paper in which the above-mentioned microcapsules and a color developer are laminated or mixed on the same surface of a support, and a capsule layer is further formed on the back surface of the single pressure-sensitive copying paper. Are provided, and they are put into practical use either alone or in an appropriate combination with the above-mentioned upper paper, middle paper, or lower paper.

Usually, the capsule layer of such pressure-sensitive copying paper is
It is formed by applying an aqueous capsule coating liquid to a support with a large-sized coating machine (hereinafter referred to as a coating method).
There is a method (hereinafter referred to as a printing method) of applying to a support with a printing machine such as flexographic printing, gravure printing, screen printing, letterpress printing, and offset printing. The printing method can produce even small lots with little loss, and is suitable for production of a large number of products in small quantities compared to the coating method.For example, pressure sensitive copy paper with a special color tone that tends to be small in lots is used. Suitable for producing.

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, for example, the upper paper or the middle paper which is entirely coated by a partial printing of a capsule ink having a different coloring color on the high quality paper or on the back surface of the lower paper or by a coating method as described in JP-A-1-301360. Various features such as a pressure-sensitive copying paper (upper 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 capsule-coated surface of A certain variety can be produced.

However, although the printing method is a production method having many merits as described above, in the case of letterpress printing or offset printing, the inclusion of capsules relative to the solid content of the ink (all components after curing and drying of the ink) Since the ratio is low, the composition is strongly affected by components other than the capsule, and the oil releasing property from the capsule is deteriorated, resulting in a problem that the coloring property is poor. In particular, this tendency is remarkable when the ultraviolet-curable capsule ink composition is subjected to letterpress printing or fusset printing, and it is a fact that a practical level has not yet been obtained.

[0008]

DISCLOSURE OF THE INVENTION The inventors of the present invention have made extensive studies in view of such problems, and as a result, it has been achieved so far when a specific compound is used as the ethylenically unsaturated compound of the capsule ink composition. It was found that a high quality capsule coated sheet which could not be obtained can be obtained.

[0009]

The present invention provides an ultraviolet-curable capsule ink composition comprising microcapsules, an ethylenically unsaturated compound, and a photopolymerization initiator as basic components.
A capsule ink composition comprising liquid polybutadiene acrylate and / or liquid hydrogenated 1,2 polybutadiene acrylate as the ethylenically unsaturated compound.

[0010]

The liquid polybutadiene acrylate or the liquid hydrogenated 1,2 polybutadiene acrylate referred to in the present invention is, for example, 2-hydroxyethyl acrylate via 2,4-tolylene diisocyanate with the hydroxyl group of the liquid polybutadiene and the urethane addition reaction. Liquid polybutadiene acrylate obtained by the above, liquid polybutadiene acrylate obtained by esterification reaction of maleic anhydride-added maleic polybutadiene with 2-hydroxy acrylate, a carboxyl group of liquid polybutadiene and glycidyl acrylate Liquid polybutadiene acrylate obtained by epoxy esterification reaction, epoxidized polybutadiene obtained by acting an epoxidizing agent on liquid polybutadiene, and acrylic acid , A liquid polybutadiene acrylate obtained by the esterification reaction of 1, a liquid polybutadiene acrylate obtained by the dehydrochlorination reaction of liquid polybutadiene having a hydroxyl group and acrylic acid chloride, and a liquid hydrogenated product obtained by modifying liquid hydrogenated 1,2 polybutadiene glycol with urethane acrylate 1 , 2 polybutadiene acrylate, and the like.

In the present invention, such a liquid polybutadiene acrylate or a liquid hydrogenated 1,2 polybutadiene acrylate is used as an ethylenically unsaturated compound in a capsule ink composition, whereby the oil release from the capsule is excellent. However, a cured film obtained by using liquid polybutadiene acrylate or liquid hydrogenated 1,2 polybutadiene acrylate is more flexible than a cured film obtained by using other ethylenically unsaturated compounds. It is speculated that

In the present invention, ethylenically unsaturated compounds known in the art other than liquid polybutadiene acrylate and liquid hydrogenated 1,2 polybutadiene acrylate can be used in combination, such as methyl methacrylate, butyl methacrylate and 2-ethoxyethyl. Acrylate, 2-phenoxyethyl (meth) acrylate, 2-
(Nonylphenoxy) ethyl (meth) acrylate, cyclohexyl methacrylate, benzyl methacrylate, trifluoroethyl methacrylate, 3-sulfopropyl methacrylate potassium salt, N- (3-sulfopropyl) -N-methacryloylamidopropyl-N, N
-Dimethylammonium betaine, glycidyl methacrylate, allyl methacrylate, dimethylaminoethyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, benzyl acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, 1-methoxycyclododecadienyl acrylate,
Dicyclopentenyl acrylate, dicyclopentenyl oxyethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2,
6-dibromo-4-t-butylphenyl acrylate,
Ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, ethoxydiethylene glycol acrylate, phenoxydiethylene glycol (meth) acrylate, phenoxy polyethylene glycol (meth) acrylate, butylphenoxydieethylene glycol (meth) acrylate, hexylphenoxydiethylene glycol (meth) ) Acrylate, octylphenoxydiethylene glycol (meth) acrylate, nonylphenoxydiethylene glycol (meth) acrylate, laurylphenoxydiethylene glycol (meth) acrylate, naphthoxydiethylene glycol (meth) acrylate, butylnaphthoxydiethylene glycol (meth) acrylate, bromnaphthoxydiethyi Glycol (meth) acrylate, hydroxyphenoxy polyethylene glycol (meth) acrylate, butyl phenoxy polyethylene glycol (meth) acrylate, hexyl phenoxy polyethylene glycol (meth) acrylate, octyl phenoxy polyethylene glycol (meth) acrylate, nonyl phenoxy polyethylene glycol (meth)
Acrylate, laurylphenoxy polyethylene glycol (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-hydroxy-3
-(P-Bromphenoxy) propyl (meth) acrylate, 2-hydroxy-3- (o-methylphenoxy)
Propyl (meth) acrylate, 2-hydroxy-3-
(P-Methylphenoxy) propyl (meth) acrylate, 2-hydroxy-3- (p-ethylphenoxy) propyl (meth) acrylate, 2-hydroxy-3-
(P-Propylphenoxy) propyl (meth) acrylate, 2-hydroxy-3- (p-butylphenoxy)
Propyl (meth) acrylate, 2-hydroxy-3-
(O, p-dimethylphenoxy) propyl (meth) acrylate, 2-hydroxy-3- (p-hexylphenoxy) propyl (meth) acrylate, 2-hydroxy-3- (p-octylphenoxy) propyl (meth) acrylate, 2-hydroxy-3- (p-nonylphenoxy) propyl (meth) acrylate, 2-hydroxy-3- (p-laurylphenoxy) propyl (meth) acrylate, 2-hydroxy-3-naphthoxypropyl (meth) acrylate, 2-hydroxy-3- (butylnaphthoxy) propyl (meth) acrylate, 2-hydroxy-3-ethoxypropyl (meth) acrylate,
2-hydroxy-3-propoxypropyl (meth) acrylate, 2-hydroxy-3-butoxypropyl (meth) acrylate, 2-hydroxy-3-lauroxypropyl (meth) acrylate, 2-hydroxy-3-
(4-chlorobutoxy) propyl (meth) acrylate, 1,2-butanediol di (meth) acrylate,
1,3-butanediol di (meth) acrylate, 1,
4-butanediol di (meth) acrylate, 1,6-
Hexanediol di (meth) acrylate, neopentyl glycol diacrylate, glycerol dimethacrylate, glycerol methacrylate acrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, neopentyl glycol hydroxypivalate Ester diacrylate, 2,2-bis [4- (acryloyloxydiethoxy) phenyl] propane, caprolactone adduct of hydroxypivalic acid neopentyl glycol ester, diacrylate of acetal compound of hydroxypivalaldehyde and trimethylolpropane. Acrylate, diallyloxy diacryloyloxycyclohexane, tri Tyrole propane propylene oxide adduct triacrylate, dipentaerythritol lower fatty acid and acrylic acid ester, dipentaerythritol caprolactone adduct acrylate, dioctyl 2-acryloyloxyethyl phosphate, diphenyl 2-acryloyloxyethyl phosphate and the like. Be done. The ethylenically unsaturated compound is usually blended in the capsule ink in the range of 30 to 95% by weight.

The photopolymerization initiator used in the present invention includes:
Aromatic ketones such as benzoquinone, phenanthrenequinone, naphthoquinone, diisopropylphenanthrenequinone, benzoisobutyl ether, benzoin, furoin butyl ether, Michler's ketone, Michler's thioketone, fluorenone, trinitrofluorenone, β-benzoylaminonaphthalene, quinone Examples thereof include compounds, ether compounds and nitro compounds. The photopolymerization initiator is usually 1 to 2 with respect to 100 parts by weight of the ethylenically unsaturated compound.
It is added in the range of 0 parts by weight.

A sensitizer may be added to further accelerate the polymerization. Examples of such a sensitizer include triethanolamine, N-methyldiethanolamine, N,
Examples thereof include N-dimethylethanolamine and N-methylmorpholine. The sensitizer is an ethylenically unsaturated compound 1
It is usually added in the range of 0 to 10 parts by weight with respect to 00 parts by weight.

When this capsule ink composition is used for pressure-sensitive copying paper, it is usually used by encapsulating an electron-donating color former in microcapsules. Electron-donating color formers 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-dimethylaminophthalide and other triallylmethane dyes, 4,4-
Bis-dimethylaminobenzhydrylbenzyl ether, N-halophenyl leuco auramine, N-2,4
Diphenylmethane dyes such as 5-trichlorophenyl leuco auramine, benzoyl leuco methylene blue, P
-Thiazine dyes such as nitrobenzoyl leuco methylene blue, spiro dyes such as 3-methyl-spiro-dinaphthopyran, 3-phenyl-spiro-dinaphthopyran, 3-propyl-spiro-dibenzopyran, rhodamine-B
-Lactam dyes such as anilinolactam, 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 Fluorane dyes such as -7-phenylaminofluorane, 3-piperidino-methyl-7-phenylaminofluorane, 3-diethylamino-6-methyl-7-xylidinofluorane, 3,3-bis [2- ( Infrared coloring dyes such as p-dimethylaminophenyl) -2- (p-methoxyphenyl) ethylene-2-yl] -4,5,6,7-tetrachlorophthalide and the like can be mentioned, and these are used alone. Alternatively, they are used together.

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: Kerosene, paraffin, naphthene oil, chlorinated paraffin and other mineral oils: alkylated biphenyl, alkylated terphenyl, alkylated naphthalene, diarylethane, triarylmethane, aromatic hydrocarbons such as 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 capsules varies depending on the film material used or the film thickness and cannot be generally stated, but usually 1 to
It is 10 μm. Further, the capsule may contain an antioxidant, an ultraviolet absorber, a fragrance, etc., if necessary.

The capsules obtained by the above method are
It is usually an aqueous dispersion, which is in a semi-third state after filtration or is dried by aeration, surface drying, fluidized drying, gas stream drying, spray drying, vacuum drying, freeze drying, infrared ray drying, high frequency drying, ultrasonic wave. After being subjected to treatments such as drying and fine pulverization drying, it is dispersed in the following non-aqueous ink medium in a dried state, and various auxiliaries are further added if necessary to form a capsule ink. As described in JP-A-53-135718, a method of mixing an aqueous capsule dispersion liquid with a non-aqueous medium and then removing water under reduced pressure, or a non-aqueous medium mixed with water after filtering the capsule dispersion liquid. The capsules can be dispersed in the non-aqueous ink medium by the method of washing and replacing with.
The capsule content in the capsule ink is usually adjusted to be in the range of 5 to 60 parts by weight with respect to 100 parts by weight of the ink.

As the ink medium used in the capsule ink of the present invention, a thixotropic agent, a high-boiling medium, a low-boiling medium, a resin, a wax or an oil may be used in combination, if necessary, in addition to the above compounds. These are usually blended in the capsule ink in the range of 0 to 60% by weight.

As the thixotropic agent, for example, colloidal silica, metal soap (aluminum stearate, aluminum octanoate, etc.), sodium palmitate, aluminum chelate (aluminum diisopropoxide monoacetoacetate ethyl, etc.), organic amine-modified bentonite. , Thixotropic polyamide resin, etc., and they are usually blended in the capsule ink in the range of 0 to 20% by weight.

Examples of the high boiling point medium 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.

As the low boiling point medium, for example, methanol,
Examples thereof include ethanol, n-propanol, iso-propanol, n-butanol, ethyl acetate, propyl acetate, butyl acetate, acetone, methyl ethyl ketone, benzene, toluene and xylene.

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 phenol 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, modified polyvinyl alcohol, polyvinyl butyral, Examples thereof include polyvinylpyrrolidone, ethyl cellulose, nitrocellulose, hydroxypropyl cellulose, cellulose acetate propionate and cellulose acetate butyrate.

Examples of the waxes include beeswax, whale wax, lanolin, candelilla wax, carnauba wax, wood wax, rice wax, montan wax,
Ozokerite, paraffin wax, microcrystalline wax, montan wax derivative, paraffin wax derivative, microcrystalline wax derivative,
Castor wax, opal wax, low molecular weight polyethylene, distearyl ketone, caprylic acid amide, stearic acid amide, ethylenebisstearic acid amide, stearic acid, behenic acid, stearyl alcohol,
Examples thereof include distearyl phosphate.

Examples of the oils include vegetable oils such as linseed oil, safflower oil, soybean oil and castor oil: processed oils such as dehydrated castor oil, polymerized oil, maleated oil, vinyl oil and urethane oil: machine oil, spindle oil Mineral oil and the like.

In the capsule ink of the present invention, if necessary, a tilting material such as cellulose powder, starch particles, synthetic resin particles, titanium oxide, surface-treated titanium oxide, zinc oxide, calcium carbonate, aluminum hydroxide, silica, etc. The white pigment, a desensitizing component for color development such as a desensitizer, an ultraviolet absorber, an antioxidant, a fluorescent whitening agent, a plasticizer, a coloring dye and the like can be appropriately added as necessary. Above all, addition of titanium oxide or surface-treated titanium oxide is particularly preferable because it can prevent the printed part from becoming transparent.

The ethylenically unsaturated compound used in the present invention is a combination system of a liquid polybutadiene acrylate or a liquid hydrogenated 1,2 polybutadiene acrylate with a system having a lower viscosity, or a high-boiling medium. A low boiling point medium and an addition system of oils are preferable from the viewpoint of color development when used as an ink for pressure-sensitive copying paper. Above all, a thixotropic agent addition system is preferable in terms of prevention of dripping and prevention of ink mist.

The ink is usually prepared by adding microcapsules and other auxiliaries to the ink medium and thoroughly mixing them using a propeller disperser, an ultrasonic disperser, a ball mill, or a triple roll. The viscosity of the ink is 300
0 cps (25 ° C.) or higher is preferable. Incidentally, when the viscosity of the prepared ink is less than 3000 cps (25 ° C.), there is a problem that dripping is likely to occur in letterpress printing and ink mist is likely to occur in offset printing, which makes stable operation difficult.

[0029] Capsules ink thus prepared is on a variety of supports by letterpress printing or offset printing, usually dry weight 1 to 10 g / m ^2, preferably 2 to 6 g / m ²
It is applied so that it becomes the range of. The ink of the present invention can also be used as a printing ink for screens and the like.

The support used for printing is, for example, high-quality paper, synthetic paper, film, art paper, coated paper, cast coated paper, lightly coated paper, pressure-sensitive copying paper (upper paper, middle paper, lower paper). , Cercon paper) and the like.

The substance contained in the capsule of the capsule ink of the present invention is not limited to the material for pressure-sensitive copying paper, and for example, perfume, liquid crystal, temperature indicating material, rust preventive, insect repellent, rodenticide, adhesive agent. Agents, adhesives and the like.

[0032]

EXAMPLES In order to further clarify the effects of the present invention, examples and comparative examples will be described below, but the present invention is not limited to these examples. In addition, unless otherwise indicated, the part and% in an example represent a weight part and weight%, respectively.

[Preparation of lower paper] Ethylene-maleic anhydride copolymer (trade name EMA-3) adjusted to pH 6.0
(1 manufactured by Monsanto Co.) was emulsified with 200 parts of a 3% aqueous solution of alkyldiphenylethane as an internal phase oil,
The system was heated to 55 ° C. Separately, add 15 parts of melamine to 45 parts of 37% formaldehyde aqueous solution, and add 1 part at 60 ° C.
An aqueous prepolymer solution was prepared by reacting for 5 minutes.

This prepolymer aqueous solution was added dropwise to the emulsion, and 0.1N hydrochloric acid was added dropwise with stirring to add p.
After adjusting H to 5.3, the system was heated to 80 ° C. and stirred for 1 hour, 0.2N hydrochloric acid was added dropwise to lower the pH to 3.5, and the mixture was stirred for another 3 hours and then cooled. Thus, a dispersion liquid of oil capsules having an average particle diameter of 5.0 μm was obtained.

Next, 60 parts of light calcium carbonate, 10 parts of zinc oxide, a mixture of zinc 3,5-di (α-methylbenzyl) salicylate and an α-methylstyrene-styrene copolymer (mixing / melting ratio 80 / 20) 10 parts, 10 parts of the above oil capsules, and 10 parts of pulp powder are dispersed in 300 parts of a 0.2% polyvinyl alcohol aqueous solution, and gelatinized starch 10 is further added.
Parts (solid content) and 15 parts (carboxyl-modified styrene-butadiene latex) (solid content) were added and diluted to obtain a 30 wt% developer coating solution.

This developer coating solution was applied to JIS-P8117-
A base paper of 40 g / m ² having an air permeability of 13 sec based on 1980 was smeared with an air knife coater so that the dry weight was 7 g / m ² , to obtain a lower paper A. Also, the air permeability is 13
sec calcium 40g / m ² base paper with light calcium carbonate 10
0 part was dispersed in 100 parts of 0.2% aqueous sodium polyacrylate solution, and further 10 parts of gelatinized starch (solid content), 10 parts of carboxy-modified styrene-butadiene latex (solid content), 1 part of carboxymethyl cellulose and 1 part of hydroxyethyl cellulose. 30% by weight of a pigment coating solution prepared by adding the above components under stirring was coated on one side with an air knife coater so that the dry weight was 7 g / m ² , to obtain a base paper having an air permeability of 52 sec. The above-mentioned color developer coating liquid was smeared on the pigment-coated surface of the base paper with an air knife coater so that the dry weight was 7 g / m ² .

Example 1 (Preparation of Microcapsules Encapsulating Electron-Donating Coloring Agent) 3,
25 parts of 3-bis (2-methyl-1-octyl-3-indolyl) phthalide was dissolved in 75 parts of benzyltoluene by heating to obtain an internal phase oil. Subsequently, an ethylene-maleic anhydride copolymer (trade name EMA-3) whose pH was adjusted to 6.0
The internal phase oil was emulsified in 200 parts of a 3% aqueous solution (1 manufactured by Monsanto Co., Ltd.), and the temperature of the system was raised to 55 ° C.

Separately, 37% formaldehyde aqueous solution 45
15 parts of melamine was added to each part and reacted at 60 ° C. for 15 minutes to prepare an aqueous prepolymer solution. This prepolymer aqueous solution was added dropwise to the emulsion, and the mixture was further stirred with 0.1.
After adding N hydrochloric acid dropwise to adjust the pH to 5.3, the system was heated to 80 ° C.
The mixture is heated to 1 hour and stirred for 1 hour, 0.2N hydrochloric acid is added dropwise to lower the pH to 3.5, and the mixture is stirred for 3 hours and then cooled to disperse capsules having an average particle diameter of 3.8 μm. A liquid was obtained. The dispersion was then filter pressed and subsequently air dried to give powder capsules.

(Preparation of Capsule Ink) 100 Parts of Microcapsules Encapsulating Electron-Donating Coloring Agent Ethylenically Unsaturated Compound [2-hydroxyethyl acrylate and hydroxyl group in liquid polybutadiene via 2,4-tolylene diisocyanate Liquid polybutadiene acrylate obtained by urethane addition reaction (hereinafter referred to as liquid polybutadiene acrylate A): dipropylene glycol diacrylate = 1:
1] 300 parts: 10 parts of a photopolymerization initiator (benzoin methyl ether) was added and mixed to prepare a capsule ink.

(Preparation of upper paper) 40 g / m²On the base paper
Letterpress printing of the capsule ink (ink amount 5.0 g /
m ²) And cure using a 6 kW UV irradiation device
Got the paper.

(Evaluation) When the upper paper thus obtained was overlaid on the lower paper A and printed with a typewriter, an extremely clear color image was obtained on the lower paper surface corresponding to the portion where the capsules were printed.

Example 2 In the preparation of a capsule ink, a liquid polybutadiene acrylate (obtained by esterifying 2-hydroxy acrylate with maleated polybutadiene having maleic anhydride added by an ene addition reaction as an ethylenically unsaturated compound ( Hereinafter referred to as liquid polybutadiene acrylate B): dipropylene glycol diacrylate =
1: 1] was used and an upper paper was prepared and evaluated in the same manner as in Example 1. The color image obtained was extremely clear.

Example 3 In the preparation of a capsule ink, a liquid polybutadiene acrylate (hereinafter referred to as liquid polybutadiene acrylate C) obtained by a dehydrochlorination reaction of liquid polybutadiene having a hydroxyl group and acrylic acid chloride as an ethylenically unsaturated compound was prepared. An upper paper was prepared and evaluated in the same manner as in Example 1 except that 300 parts of dipropylene glycol diacrylate = 1: 1] was used.
The color image obtained was extremely clear.

Example 4 In the preparation of a capsule ink, [liquid polybutadiene acrylate A: 2-
Preparation of upper paper in the same manner as in Example 1 except that 300 parts of (nonylphenoxy) ethyl acrylate = 1: 1] was used and 5 parts of colloidal silica (trade name: Aerosil 200, manufactured by Nippon Aerosil Co., Ltd.) was further added. And evaluated. The color image obtained was extremely clear. still,
No dripping occurred at the time of printing.

Example 5 In the preparation of a capsule ink, a liquid polybutadiene acrylate A: 1,6 was used as an ethylenically unsaturated compound.
-Hexanediol diacrylate = 1: 1] 300
An upper sheet was prepared and evaluated in the same manner as in Example 1 except that the parts were used. The color image obtained was extremely clear.

Example 6 In the preparation of a capsule ink, 300 parts of [liquid polybutadiene acrylate A: dipropylene glycol diacrylate: 2- (nonylphenoxy) ethyl acrylate = 1: 1: 1] was used as an ethylenically unsaturated compound. An upper sheet was prepared and evaluated in the same manner as in Example 1 except for the above. The color image obtained was extremely clear.

Example 7 An upper paper was prepared in the same manner as in Example 1 except that 300 parts of liquid polybutadiene acrylate A was used as the ethylenically unsaturated compound in the preparation of the capsule ink.
An evaluation was made. The color image obtained was inferior to that of Example 1, but was clear.

Example 8 In the preparation of a capsule ink, 240 parts of liquid polybutadiene acrylate A was used as an ethylenically unsaturated compound, and 80 parts of ethanol and 5 parts of Aerosil 200 were used.
An upper sheet was prepared and evaluated in the same manner as in Example 1 except that parts were added. The color image obtained was extremely clear.

Example 9 In the preparation of the capsule ink, the same procedure as in Example 1 was carried out except that 200 parts of liquid polybutadiene acrylate A was used as the ethylenically unsaturated compound, and 80 parts of cellosolve and 50 parts of pentaerythritol ester of rosin were added. Then, the upper paper was prepared and evaluated. The color image obtained was extremely clear.

Example 10 An upper paper was prepared in the same manner as in Example 1 except that 220 parts of liquid polybutadiene acrylate B was used as the ethylenically unsaturated compound in the preparation of the capsule ink and 100 parts of ethylene glycol was further added. , Evaluated. The color image obtained was extremely clear.

Example 11 In the preparation of a capsule ink, an ethylenically unsaturated compound [liquid hydrogenated 1,2 polybutadiene acrylate obtained by modifying liquid hydrogenated 1,2 polybutadiene glycol with urethane acrylate (hereinafter referred to as liquid hydrogenated 1,2 polybutadiene] An upper paper was prepared and evaluated in the same manner as in Example 1 except that 300 parts of (Acrylate D): dipropylene glycol diacrylate = 1: 1] was used. The color image obtained was extremely clear.

Example 12 In the preparation of a capsule ink, 170 parts of liquid hydrogenated 1,2 polybutadiene acrylate D was used as an ethylenically unsaturated compound, and 80 parts of propylene glycol and 50 parts of pentaerythritol ester of rosin were added. In the same manner as in Example 1, a top sheet was prepared and evaluated. The color image obtained was extremely clear.

Example 13 An upper paper was prepared and evaluated in the same manner as in Example 1 except that 300 parts of liquid hydrogenated 1,2 polybutadiene acrylate D was used as the ethylenically unsaturated compound in the preparation of the capsule ink. It was The color image obtained is from Example 1.
It was worse but sharper.

Example 14 (Preparation of upper paper) 40 g / m ² base paper was overlaid twice with the capsule ink prepared in the same manner as in Example 1 and offset printing (ink amount 4.0 g / m ² ) was performed, and 6 kW was obtained. The upper paper was obtained by curing using the ultraviolet irradiation device.

(Evaluation) When the upper paper thus obtained was placed on the lower paper A and printed with a typewriter, an extremely clear color image was obtained on the lower paper surface corresponding to the portion where the capsules were printed.

Example 15 (Preparation of Medium Paper) On the surface of the lower paper B opposite to the developer layer, the capsule ink prepared in the same manner as in Example 1 was letterpress-printed (ink amount: 5.0 g / m ² ). Then, it was cured using a 6 kW ultraviolet irradiation device to obtain a medium paper.

(Evaluation) When the thus obtained middle paper A was overlaid on the lower paper and printed by a typewriter, an extremely clear color image was obtained on the surface of the lower paper corresponding to the portion where the capsules were printed. It should be noted that generation of short-circuit stain was not observed at all on the obtained middle paper.

Example 16 (Preparation of Medium Paper) On the opposite surface of the lower paper A from the color developer layer, capsule ink prepared in the same manner as in Example 1 was letterpress-printed (ink amount 5.0 g / m ² ). Then, it was cured using a 6 kW ultraviolet irradiation device to obtain a medium paper.

(Evaluation) When the thus obtained middle paper A was overlaid on the lower paper and printed with a typewriter, a very clear color image was obtained on the lower paper surface corresponding to the portion where the capsules were printed. The obtained middle paper had short stains.

Comparative Example 1 In the preparation of a capsule ink, 3 [pentaerythritol triacrylate: pentaerythritol tetraacrylate = 1: 1] was used as an ethylenically unsaturated compound.
An upper sheet was prepared and evaluated in the same manner as in Example 1 except that 00 copies were used. The obtained color image was inferior to the level where it was not practical.

Comparative Example 2 As an ethylenically unsaturated compound, [pentaerythritol triacrylate: pentaerythritol tetraacrylate: dipropylene glycol diacrylate = 1:
1: 1] was used and an upper paper was prepared and evaluated in the same manner as in Example 1. The obtained color image was inferior to the level where it was not practical.

Comparative Example 3 An upper paper was prepared and evaluated in the same manner as in Example 1 except that 300 parts of [trimethylolpropane triacrylate: trimethylolpropane diacrylate = 1: 1] was used as the ethylenically unsaturated compound. I went. The obtained color image was inferior to the level where it was not practical.

Comparative Example 4 As an ethylenically unsaturated compound, [trimethylolpropane triacrylate: trimethylolpropane diacrylate: dipropylene glycol diacrylate = 1:
1: 1] was used and an upper paper was prepared and evaluated in the same manner as in Example 1. The obtained color image was inferior to the level where it was not practical.

Comparative Example 5 An upper paper was prepared and evaluated in the same manner as in Example 1 except that 300 parts of 1,6-hexanediol diacrylate was used as the ethylenically unsaturated compound. The obtained color image was inferior to the level where it was not practical.

Comparative Example 6 An upper paper was prepared and evaluated in the same manner as in Example 1 except that 300 parts of dipropylene glycol diacrylate was used as the ethylenically unsaturated compound. The obtained color image was inferior to the level where it was not practical.

[0066]

EFFECTS OF THE INVENTION Since the pressure-sensitive copying paper thus obtained exhibits extremely excellent color-forming property, the capsule ink composition of the present invention can be used as a practical product because a high-quality capsule-coated sheet can be obtained. Is.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shunsuke Shioi 4-3-1 Jokoji, Amagasaki City, Hyogo Prefecture Kanzaki Paper Co., Ltd. Kanzaki Mill (72) Inventor Hirokazu Furukawa 4-3-1 Jokoji Temple, Amagasaki City, Hyogo Prefecture No. Kanzaki Paper Manufacturing Co., Ltd. Kanzaki Mill

Claims (1)

[Claims] 1. A UV-curable capsule ink composition comprising microcapsules, an ethylenically unsaturated compound and a photopolymerization initiator as basic components, wherein a liquid polybutadiene acrylate and / or a liquid hydrogenated 1, is used as the ethylenically unsaturated compound. 2. A capsule ink composition comprising a polybutadiene acrylate.