JPH0995045A - Capsule ink for pressure sensitive reproduction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a capsule ink for pressure sensitive reproduction hardly causing coloring stain due to capsule breakdown when preparing an ink or manufacturing a pressure sensitive copying sheet and also almost free from coloring stain due to capsule breakdown caused by friction, in the capsule ink for pressure sensitive reproduction enveloping a color coupler. SOLUTION: This capsule ink for pressure sensitive reproduction consists of a microcapsule enveloping an electron-donative color coupler, an ultraviolet curable compound and a photopolymerization initiator as basic components. In addition, this capsule ink contains at least, either of a polyethylene microparticle or a polyurethane microparticle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive copying capsule ink in which microcapsules containing an electron-donating color-forming agent are made into ink, and the capsules are destroyed during ink preparation, pressure-sensitive copying sheet production and use. The present invention relates to a capsule ink for pressure-sensitive copying, which is less likely to cause color stains.

[0002]

2. Description of the Related Art Electron-donating color formers such as crystal violet lactone and benzoyl leuco methylene blue,
Pressure-sensitive copying sheets utilizing the principle of developing color by reaction with an electron-accepting developer such as activated clay, phenol-formaldehyde condensate, and polyvalent metal salt of aromatic carboxylic acid are well known.

In general, such a pressure-sensitive copying sheet is prepared by coating a support with microcapsules containing an electron-donating color former prepared by a method such as a phase separation method, an interfacial polymerization method, an in-situ method or the like. Sheet (CB sheet), lower sheet (CF sheet) having a support coated with an electron-accepting color developer that reacts with an electron-donating color developing agent, the color-developing agent microcapsules and the color developing agent as a support The intermediate-use sheets (CFB sheets) applied to the separate surfaces of (1) and (2) are put together for practical use as a set.

There is also a so-called self-coloring type pressure-sensitive copying sheet in which a color-developing agent microcapsule and a color-developing agent are separately applied on the same surface of a support as a laminated or mixed layer, and the self-coloring type pressure-sensitive copying sheet. There is a set of a self-coloring type pressure-sensitive copying sheet in which a capsule layer is provided on the back surface of the sheet and a lower sheet and a middle sheet are properly combined.

Usually, these pressure-sensitive copying sheets are manufactured by applying a water-based paint to a support with a large-sized coating machine. As a special manufacturing method, microcapsules containing a color-forming agent are used. There is a method of making ink and spot printing with a printing machine. Since spot printing of capsule ink can print expensive capsule paint only on the required parts of the support, compared with the method of coating the entire surface of the support with a large-scale coating machine, for example, partial color tone There is a small swirling effect such that different pressure sensitive copy sheets can be obtained, and depending on the intended product type, it exhibits economically excellent characteristics.

However, while such a printing method has a great advantage as compared with the method using a coating machine, any of the printing methods of flexographic printing, gravure printing, screen printing, letterpress printing and offset printing has the following drawbacks. It has either of them, and there is a strong demand for improvement.

(1) Capsules are destroyed during the production of ink, and color stains are likely to occur. (2) Capsules are easily broken during printing, and color stains are likely to occur. (3) Since a solvent is used, there is a problem in terms of environment and safety.

In particular, in the case of microcapsules containing a color-forming agent and capsule inks containing a UV-curable compound and a photopolymerization initiator as basic components, in the case of letterpress printing or offset printing, the problems (1) and (2) above are encountered. Because of this, a practical level has not yet been obtained. With these inks, the capsules are easily broken and color stains are liable to occur during the preparation of the ink or the production of the pressure-sensitive copying sheet.

To date, in the field of pressure-sensitive copying paper, in order to prevent inadvertent destruction of capsules during handling, stilts have been added to the capsule coating liquid, and natural starch granules and pulp powders have been added. Has been added. But,
When these are added to a high concentration capsule ink containing a solvent,
The viscosity increases, making it difficult to prepare paint. In addition, the solvent-free encapsulation ink for letterpresses has a large viscosity increase even with a small amount of tilt, and the addition of pulp powder or starch granules, which are natural products, causes thickening and makes it difficult to prepare a high-concentration ink. Further, some of the synthetic resin fine powders may swell or change the properties of the paint when added to the capsule ink.

When a capsule ink containing a huge stilt is printed, the huge stilt in the ink is not taken to the paper and settles in a paint reservoir, or in a can during storage, and the sediment becomes hard. However, when the ink is taken out of the can, it is difficult to take out the components of the ink uniformly.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide a color-forming agent-containing capsule ink for pressure-sensitive copying, in which color stain due to capsule destruction is less likely to occur during ink preparation or pressure-sensitive copying sheet production. It is an object of the present invention to provide a capsule ink for pressure-sensitive copying, which is less likely to cause an inadvertent pressure during the production of a pressure-sensitive copying sheet or before use, or to cause color stains due to capsule destruction due to friction.

[0012]

DISCLOSURE OF THE INVENTION The present invention provides a microcapsule containing an electron-donating color former, a UV-curable compound and a pressure-sensitive copying capsule ink containing a photopolymerization initiator as a basic component. By adding at least one kind of fine particles to the ink, it was found that a high quality capsule ink which could not be achieved up to now can be obtained.

The average particle size of polyethylene fine particles and urethane fine particles is preferably 10 to 35 μm. If the average particle size is 10 μm or less, the capsules are easily broken during the production of the ink or during printing, and if it is 35 μm or more, the capsules are easily detached from the support due to friction and the like, which causes stains. The polyethylene fine particles and urethane fine particles used in the present invention, when added to a capsule ink, have little swelling or thickening, little sediment, and easy re-dispersion,
There is no trouble during storage.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A pressure-sensitive copying sheet obtained by using the pressure-sensitive copying capsule ink of the present invention is obtained, for example, by printing and coating a microcapsule ink containing an electron-donating color-forming agent on a support. Sheet, medium-use sheet, self-coloring type pressure-sensitive copying sheet, etc. face the capsule surface with the developer surface of the medium-use sheet, lower sheet, and usually pressure from the back of the capsule surface such as writing pressure or impact printer pressure. By destroying the capsules and transferring the encapsulated color-forming agent dye solution to the developing surface, a recorded image corresponding to the pressure is developed on the developing surface.

The electron-donating color former used in the present invention is, for example, the following known in the field of pressure-sensitive copying sheets, for example, triallylmethane dyes, diphenylmethane dyes, thiazine dyes and spiro. System dyes, lactam dyes, fluorane dyes, infrared coloring dyes and the like, and mixtures thereof.

Further, as the electron-accepting developer, for example, clays such as acid clay, activated clay, attapulgite, zeolite and bentonite which are well known in the field of pressure-sensitive copying sheets are described below. , Phenol resins, polyvalent metal salts of various aromatic carboxylic acids described in JP-B-51-25174, zinc salts of 2,2'-bisphenol sulfone compounds as described in JP-A-54-106316, and the like. There are mixtures etc.

In the method for producing a capsule ink for pressure-sensitive copying of the present invention, the above-mentioned electron-donating color former is encapsulated in microcapsules to form an ink. Then, it is used as an ink for printing and coating on a support using a printing machine.

In order to microencapsulate the electron-donating color former, the color former is encapsulated in a state of being dissolved in the internal phase oil. Examples of the oil for the internal phase include vegetable oils, animal oils, mineral oils, aromatic hydrocarbons, alcohols, organic acids, esters, organic phosphoric acid compounds, ethers, amides, ketones, alkylene carbonates. There are substances such as classes and the like and mixtures thereof. The compounding amount of the color former is usually adjusted in the range of about 1 to 20 parts by weight with respect to 100 parts by weight of the internal phase oil.

As the encapsulation method, conventionally known coacervation method, interfacial polymerization method, in-situ method and the like can be appropriately selected and used, but it is preferable to use a synthetic resin as a wall film material. However, capsules coated with a melamine-formaldehyde resin are particularly preferable because a pressure-sensitive copying sheet that is more excellent in quality such as color vividness can be obtained.

If desired, these microcapsules may contain an antioxidant, an ultraviolet absorber, and the like. Examples of the UV absorber include benzophenone-based, benzotriazole-based, and cyanoacrylate-based UV absorbers.

Examples of the UV-curable compound include compounds having one or more, preferably a plurality of vinyl groups or vinylidene groups, specifically, an acryloyl group,
There are compounds having a methacryloyl group, an allyl group, an unsaturated polyester, a vinyloxyacrylamide group, and the like. The photopolymerization initiator includes, for example, aromatic ketones, quinone compounds, ether compounds, nitro compounds and the like. The compounding amount of the photopolymerization initiator is usually in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the ultraviolet curable compound.

As the organic polymer type fine particle material, crosslinked acrylic resin, methacrylic resin, fluorine resin, vinylidene fluoride resin, benzoguanamine resin, silicone resin, epoxy resin, nylon 6, nylon 66, nylon 11, nylon 12, polystyrene. There are fine particles of resin, crosslinked polystyrene resin, phenol resin, melamine resin, polyolefin resin, polyethylene resin, cellulose and the like.

However, when it is used as an ink, there is little thickening when added to the ink, there is no adverse effect on other materials used, the chemical resistance to volatile organic solvents is excellent, and the produced feeling is good. Polyethylene fine particles and urethane fine particles having excellent water resistance and moisture resistance of the pressure copying sheet are preferable.

The average particle size of polyethylene fine particles is 10 to 3
5 μm is preferred. If the average particle size is 10 μm or less, there is no effect of improving pressure resistance, and if it is 35 μm or more, problems such as abrasion resistance, dispersibility during ink preparation, and particle sedimentation during long-term storage occur.

The amount of polyethylene fine particles mixed in the ink medium is preferably 5 to 100 parts by weight, more preferably 10 to 60 parts by weight, based on 100 parts by weight of the capsule.

The urethane fine particles are manufactured by the method for manufacturing microcapsules. As the encapsulation method, conventionally known coacervation method, interfacial polymerization method, in
The -situ method or the like can be appropriately selected and used, but in the present invention, the interfacial polymerization method can efficiently produce fine urethane particles.

In the present invention, urethane fine particles are prepared using an aliphatic or aromatic polyvalent isocyanate compound.

As the polyvalent isocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate, naphthalene-1,4-diisocyanate, diphenylmethane-4,4'- Diisocyanate, 3,3'-dimethoxy-4,4'-biphenyl diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, xylylene-1,4-
Diisocyanate, xylylene-1,3-diisocyanate, 4,4'-diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, ethylidyne diisocyanate, cyclohexylene- 1,2-diisocyanate, cyclohexylene-1,4-diisocyanate, isophorone diisocyanate, p-phenylene diisothiocyanate, xylylene-1,4-diisothiocyanate, ethylidyne diisothiocyanate, dimethylsilyl diisocyanate, vinylmethylsilyl isocyanate, 4-isocyanate methyl-1,8-octamethylene diisocyanate, lysine diisocyanate,
Diisocyanates or diisothiocyanates such as bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane diisocyanate, trimethylhexamethylene diisocyanate, 4,4 ′, 4 ″ -triphenylmethane triisocyanate, toluene-2,4,6-triisocyanate, tris ( Isocyanate phenyl)
Thiophosphate, methylsilyltriisocyanate,
Vinylsilyl triisocyanate, phenylsilyl triisocyanate, octadecylsilyl triisocyanate, methoxysilane triisocyanate, butoxysilane triisocyanate, octylsilane triisocyanate, 2,6-diisocyanatecaproic acid-β-isocyanate ethyl ester, 2,6-diisocyanatecapron Acid-γ-isocyanatopropyl ester,
2,6-Diisocyanate caproic acid-2-methyl-β
-Isocyanate ester, triisocyanate such as hexamethylene diisocyanate trimer, polymethylene polyphenyl isocyanate, 4,4'-dimethyldiphenylmethane-2,2 ', 5,5'-tetraisocyanate, tetraisocyanate silane, hexamethylene Polyisocyanates such as burette type polyisocyanate containing a residue derived from diisocyanate and isophorone diisocyanate, and these polyvalent isocyanates as polyvalent amine, polyvalent carboxylic acid, polyvalent thiol, polyvalent hydroxy compound, epoxy Examples thereof include those added to a compound having a hydrophilic group such as a compound.

In the present invention, the above-mentioned aliphatic or aromatic polyvalent isocyanate compound is used alone or as a mixture in order to prepare urethane fine particles. The type and amount of the polyvalent isocyanate compound are appropriately adjusted according to the performance value of the desired urethane fine particles, and are not particularly limited.

Examples of the hydrophobic liquid used together with the polyvalent isocyanate include compounds having one or more, preferably a plurality of vinyl groups or vinylidene groups, specifically, acryloyl group, methacryloyl group, allyl group, Examples include saturated polyesters and compounds having a vinyloxyacrylamide group.

A radical polymerization initiator is preferably added to the above hydrophobic liquid. As the radical polymerization initiator, azobisisobutyronitrile, azobis-2,4
-Dimethyl valeronitrile, azobiscyclohexanecarbonitrile, azo polymerization initiators such as methyl azobisisobutyrate, diisopropyl peroxydicarbonate,
2,4-dichlorobenzoyl peroxide, lauroyl peroxide, benzoyl peroxide, cyclohexanone peroxide, t-butyl perbenzoate, dicumyl peroxide, di-t-butyl peroxide, p-menthane hydroperoxide, pinane hydroperoxide, cumene hydroperoxide , T-butyl hydroperoxide and other peroxide-based polymerization initiators.

Usually, in the interfacial polymerization method, in order to efficiently emulsify and disperse a hydrophobic liquid containing a polyvalent isocyanate in a hydrophilic liquid, water as a hydrophilic liquid or an emulsion-stabilizing agent used in a usual capsule manufacturing system is used. An aqueous solution of the agent is used. Examples of such emulsion stabilizers include polyvinyl alcohol, anion-modified polyvinyl alcohol, cation-modified polyvinyl alcohol, gelatin,
Gum arabic, carboxymethyl cellulose, polyacrylamide, hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, cellulose acetobutyrate, hydroxymethyl cellulose, polyvinylpyrrolidone, montmorillonite, lignin sulfonic acid, polystyrene sulfonic acid and its copolymer, maleic anhydride copolymer Examples thereof include decomposed products, polyacrylic acid and copolymers thereof, polymethacrylic acid and copolymers thereof, polyacrylamidomethylpropanesulfonic acid and copolymers thereof, and salts thereof. These emulsion stabilizers are used alone or as a mixture.

A polyvalent amine may be added to the hydrophilic liquid depending on the desired quality of the urethane fine particles. As such a polyvalent amine, any polyamine that has _two or more NH groups or NH ₂ groups in the molecule and can be dissolved or dispersed in a hydrophilic liquid forming a continuous phase can be used. Specific substances include aliphatic polyvalent amines such as diethylenetriamine, ethylenetriethylenetetramine, 1,3-propylenediamine, and hexamethylenediamine, epoxy compound adducts of aliphatic polyvalent amines, and alicyclic rings such as piperazine. Formula Polyamine, 3,9-bis-aminopropyl-2,4,8,10-tetraoxaspiro-
Examples include heterocyclic diamines such as (5,5) undecane.

At least one of these polyvalent amines is added to the hydrophilic liquid. The addition amount depends on the kind and amount of the polyvalent isocyanate used and the desired performance value of the urethane fine particles. Will be decided appropriately.
It is preferably adjusted in the range of 0.1 to 200 parts by weight, more preferably 1 to 100 parts by weight, based on 100 parts by weight of the polyvalent isocyanate.

The urethane fine particles obtained by the above-mentioned method are usually aqueous dispersions, which are filtered, then dried by aeration, surface drying, fluidized drying, air stream drying, spray drying, vacuum drying, freeze drying. It is added to the ink in a dried state after being subjected to treatments such as infrared drying, high frequency drying, ultrasonic drying and fine pulverization drying.

The urethane fine particles are excellent in toughness and ink fluidity which are characteristics of urethane resin. The average particle size of the urethane fine particles is preferably 10 to 35 μm. Average particle size is 10
If it is less than μm, there is no effect of improving pressure resistance, and if it is more than 35 μm, problems such as abrasion resistance, dispersibility during ink preparation, and particle sedimentation during long-term storage occur.

The amount of the urethane fine particles to be mixed in the ink medium is preferably 5 to 100 parts by weight, more preferably 1 part by weight, based on 100 parts by weight of the capsule.
It is in the range of 0 to 60 parts by weight.

The capsule ink of the present invention contains a sensitizer for enhancing the efficiency of photopolymerization, if necessary, and further a white pigment, a color desensitizing component, a capsule protecting agent, an antioxidant, a fluorescent dye, a plasticizer. Etc. can be added.

In the production method of the present invention, as a method for converting a capsule ink containing the above-mentioned basic components into an ink,
After filtering the water-dispersed microcapsules, after treatment by aeration drying, surface drying, fluidized drying, air stream drying, spray drying, vacuum drying, freeze drying, infrared drying, high frequency drying, ultrasonic drying, fine pulverization drying, etc. Is added to the ink in the dry state.

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. It

The thus-prepared microcapsule ink containing a color-forming agent for pressure-sensitive copying is, for example, paper (including neutral paper) by letterpress printing, offset printing, flexographic printing, etc. equipped with an ultraviolet irradiation device. , A synthetic paper, a film, etc., or printed on the back or front surface of a receiving sheet provided with a receiving layer on the support, the ink is cured by UV irradiation, and the upper sheet, middle sheet or self Used as a color-forming pressure-sensitive copying sheet.

The printing amount of the capsule ink is adjusted.
It is decided according to the type of ink
0.3-10 g / m by dry weight², Preferably 2-7 g
/ M ²It is a range of degrees.

As the electron-accepting developer of the receptor layer which develops color by reacting with the above-mentioned electron-donating color former, the general ones described above which are conventionally known in the production of pressure-sensitive copying sheets are used. In the present invention, it is a substance that develops color by reacting with the color former encapsulated in the microcapsules.

The developer is crushed by a ball mill, attritor, sand mill or the like, if necessary, and then an ordinary white pigment, a binder, and if necessary, a dispersant, a colored dye, a fluorescent whitening agent. , Various additives such as an ultraviolet absorber, an antioxidant and an antifoaming agent are added to prepare an aqueous coating liquid for forming a receiving layer.

Various kinds of white pigments can be used in the same manner as the substances added to the capsule ink coating layer,
Examples of the binder include water-soluble natural polymer compounds such as proteins, starches, celluloses and saccharoses, polyvinyl alcohol, polyvinylpyrrolidone, sodium polyacrylate, polyacrylamide, maleic acid copolymer salts, butadiene-methacrylic acid. Water-soluble synthetic polymer compounds such as sodium salts of styrene-butadiene latex, acrylonitrile-butadiene latex, acrylic ester latex, vinyl acetate latex, methylmethacrylate-butadiene latex and their carboxy-modified (eg acrylic acid) ) There is a latex binder and the like.

The prepared receptive layer-forming coating liquid is applied on-machine or off-machine by various known coating methods such as air knife coater, roll coater, blade coater, size press coater, curtain coater, bill blade coater and short dwell coater. With a coater, it is applied to various supports such as paper (including neutral paper), synthetic paper, film and the like.

The coating amount of the receiving layer forming coating liquid is appropriately determined according to the type of the prepared coating liquid and is not particularly limited, but generally 2 to 15 g / dry weight.
m ^{2 It is} preferably about 3 to 7 g / m ² .

[0048]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The parts and% in the examples are parts by weight and% by weight, respectively, unless otherwise specified.

Example 1 [Preparation of lower sheet] As a developer, 100 parts of zinc 3,5-di (α-methylbenzyl) salicylate was added to 10 parts of toluene.
A developer toluene solution was prepared by mixing and dissolving in 0 part at 70 ° C. Separately, 300 parts of water containing 6 parts of polyvinyl alcohol having a degree of polymerization of 1,700 and a degree of saponification of 98% was placed in a beaker made of stainless steel. K. Homo mixer for 3 minutes
The above toluene solution was added to this while stirring at 000 rpm.

When the toluene solution of the color developer was added, the number of revolutions was increased to 10,000 revolutions per minute and the mixture was stirred for 2 minutes, then the stirring was stopped, and the dispersion was equipped with a stirrer, a thermometer and a distillation port. Transferred to a hard glass three neck flask. The flask was heated while slowly rotating the stirrer so that toluene and water were distilled from the distillation port. About 1 at 100 ℃
When this operation was continued for an hour, the dispersion became almost free of toluene. This was cooled to obtain an aqueous dispersion containing about 40% of the color developer. The average particle size of the obtained developer dispersed particles was 1.0 μm.

25 parts of the aqueous developer dispersion (solid content concentration 40%), 164 parts of 55% light calcium carbonate (trade name: Brilliant S-15, manufactured by Shiraishi Kogyo Co., Ltd.) and 50 parts of water were obtained. Mix and disperse and 1 as binder
0% polyvinyl alcohol (trade name: PVA-210,
A developer coating liquid was prepared by mixing 50 parts of an aqueous solution of Kuraray Co., Ltd., 16 parts of 48% SBR latex (trade name: SN-307, manufactured by Sumitomo Dow Co., Ltd.) and 150 parts of water. Next, the above-mentioned developer coating solution was applied to one side of a base paper of 40 g / m ^{2 in} a dry weight of 5
It was coated with an air knife coater so as to be g / m ² and dried to obtain a developed surface of a lower sheet for pressure-sensitive copying sheets.

[Preparation of powder capsules] 8 parts of crystal violet lactone as a color former is dissolved by heating in 100 parts of alkyldiphenylethane (trade name: Hisol SAS-296, manufactured by Nippon Petrochemical Co., Ltd.) as an oil for internal phase. Then, a color developer-dissolved inner phase liquid was obtained. After adding 20% aqueous sodium hydroxide solution to 200 parts of a 3.0% aqueous solution of ethylene-maleic anhydride copolymer (trade name: EMA-31, manufactured by Monsanto Co.) to adjust the pH to 6.0, After emulsifying the internal phase liquid, the temperature of this system was raised to 55 ° C.

Separately, 45% aqueous 37% formaldehyde solution
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 dropped into the emulsion and 0.1N-
Hydrochloric acid was added dropwise to adjust the pH to 5.3, and the mixture was warmed to 80 ° C, kept at that temperature for 1 hour, lowered to pH 3.5 with 0.2N-hydrochloric acid, kept warm for 3 hours, and then released. After cooling, an aqueous liquid in which capsules having an average particle size of 4.5 μm were dispersed was obtained. The aqueous liquid in which the capsules were dispersed was filter-pressed and then air-dried to prepare powder capsules.

[Preparation of Capsule Ink] 100 parts of the above-mentioned powder capsules were mixed with 400 parts of an ultraviolet curable compound [2-hydroxy-3-phenoxypropyl acrylate: pentaerythritol triacrylate = 7: 3], a photopolymerization initiator (benzoin 10 parts of methyl ether), 20 parts of titanium oxide, and 50 parts of polyethylene fine particles having an average particle size of 25 μm (trade name: FLOWCEN UF-20, manufactured by Sumitomo Seika) were added and mixed to obtain a capsule ink.

[Preparation of medium-use sheet] After the above-mentioned capsule ink was letterpress-printed on the rear surface of the color-developing surface of the lower-use sheet prepared above, the ink was cured only by an ultraviolet irradiation device to give an ink amount of 4.0 g / An intermediate sheet for a pressure-sensitive copying sheet on which m ² spots were printed was obtained. The obtained printed matter had good opacity at the printed portion. Also, 100 m / mi
Even when printing was performed at a speed of n, the guide roll did not stain at all.

Example 2 Ink was prepared in the same manner as in Example 1 except that 50 parts of polyethylene fine particles having an average particle diameter of 20 μm (trade name: FLOWCEN UF-4, manufactured by Sumitomo Seika) were used. An intermediate sheet for a pressure-sensitive copy sheet was prepared to obtain a printed matter. The state of the printed matter was the same as in Example 1.

Example 3 Ink was prepared in the same manner as in Example 1 except that 50 parts of polyethylene fine particles having an average particle diameter of 12 μm (trade name: FlowBead CL-2080, manufactured by Sumitomo Seika Chemicals, Ltd.) were used. A pressure-sensitive copy sheet for intermediate use was prepared to obtain a printed matter. The state of the printed matter was the same as in Example 1.

Example 4 [Preparation of True Spherical Urethane Fine Particles] Polyvinyl alcohol (trade name: PVA) was placed in a stirring and mixing container equipped with a heating device.
150 parts of a 3% aqueous solution (-117, manufactured by Kuraray Co., Ltd.) was used as an aqueous medium for preparing urethane fine particles. Separately, 100 parts of divinylbenzene, 5 parts of polymethylene polyphenyl isocyanate (trade name: Millionate MR400, manufactured by Nippon Polyurethane Industry Co., Ltd.), 2-isocyanatoethyl-
2,6-Diisocyanate hexanoate (trade name: T
-100, manufactured by Toray) and 1,1'-azobis (cyclohexane-1-carbonitrile) (trade name: V-4)
0, manufactured by Wako Pure Chemical Industries, Ltd.) was used as a capsule core substance to prepare a solution of T.O. K. Using a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), the emulsion was dispersed at 8,000 rpm.

Diethylenetriamine 1 was added to this emulsion dispersion.
Parts and after stirring for 30 minutes at room temperature, the system temperature was adjusted to 7
The temperature was raised to 0 ° C. and the reaction was continued for 3 hours while continuing stirring.
The temperature was lowered to room temperature to prepare a dispersion of spherical polyurethane fine particles having an average particle diameter of 25 μm. Next, this dispersion was filter-pressed and then air-dried to prepare spherical polyurethane fine particles.

[Preparation of Capsule Ink] Pressure-sensitive copying was carried out in the same manner as in Example 1 except that 50 parts of the above polyurethane fine particles having an average particle size of 25 μm were used in place of the polyethylene fine particles in Example 1. An intermediate sheet for a sheet was prepared to obtain a printed matter. The state of the printed matter was the same as in Example 1.

Example 5 A pressure-sensitive copy sheet intermediate sheet was prepared in the same manner as in Example 4 except that 50 parts of polyurethane fine particles having an average particle size of 20 μm were used to obtain a printed matter. The state of the printed matter was the same as in Example 4.

Example 6 Ink was prepared in the same manner as in Example 4 except that 50 parts of polyurethane fine particles having an average particle size of 10 μm (trade name: Meltex TU-514, manufactured by Sanyo Chemical Industry Co., Ltd.) were used. A pressure-sensitive copy sheet for intermediate use was prepared to obtain a printed matter. The state of the printed matter was the same as in Example 4.

Example 7 [Preparation of capsule ink] Ethyl cellulose (trade name: N-4, manufactured by Hercules) 40 parts in 300 parts of ethanol
And 165 parts of pentaerythritol triacrylate, 5 parts of benzoin and an average particle size of 25 parts.
Polyethylene fine particles of μm (trade name: FROSEN UF-
20, manufactured by Sumitomo Seika Co., Ltd.) was added, and 100 parts of the capsule used in Example 1 was dispersed to obtain a capsule ink.

[Preparation of intermediate sheet] Prepared in Example 1
The above-mentioned capsule ink is printed on the back of the color development surface of the lower sheet.
After photographic printing, cure the ink only with the UV irradiation device.
Ink amount 4.0g / m ²Pressure sensitive with spot printing
An intermediate sheet for copy sheet was obtained. In addition, the obtained printed matter
Also had good opacity at the printed part. Also, 100
Even if you print at a speed of m / min, the guide roll will not get dirty.
It did not occur at all.

Example 8 Ink was prepared in the same manner as in Example 7 except that 30 parts of polyethylene fine particles having an average particle size of 20 μm (trade name: FLOWCEN UF-4, manufactured by Sumitomo Seika Chemicals, Ltd.) were used. An intermediate sheet for a pressure-sensitive copy sheet was prepared to obtain a printed matter. The state of the printed matter was the same as in Example 7.

Example 9 Ink was prepared in the same manner as in Example 7 except that 30 parts of polyethylene fine particles having an average particle diameter of 12 μm (trade name: Flow Beads CL-2080, manufactured by Sumitomo Seika) were used. A pressure-sensitive copy sheet for intermediate use was prepared to obtain a printed matter. The state of the printed matter was the same as in Example 7.

Example 10 Instead of the polyethylene particles in Example 7, the above polyurethane fine particles 3 having an average particle size of 25 μm used in Example 4 were used.
An ink was prepared in the same manner as in Example 4 except that 0 part was used to prepare a pressure-sensitive copy sheet intermediate sheet, and a printed matter was obtained. The state of the printed matter was the same as in Example 7.

Example 11 A pressure-sensitive copy sheet intermediate sheet was prepared in the same manner as in Example 10 except that 30 parts of polyurethane fine particles having an average particle diameter of 20 μm were used to obtain a printed matter. The state of the printed matter was the same as in Example 7.

Example 12 Ink was prepared in the same manner as in Example 10, except that 30 parts of polyurethane fine particles having an average particle diameter of 10 μm (trade name: Meltex TU-514, manufactured by Sanyo Chemical Industry Co., Ltd.) were used.
In the same manner as described above, a pressure-sensitive copy sheet intermediate sheet was prepared to obtain a printed matter. The state of the printed matter was the same as in Example 7.

Comparative Example 1 A medium-use sheet for a pressure-sensitive copying sheet was prepared in the same manner as in Example 1 except that polyethylene particles were not mixed in the ink preparation.

Comparative Example 2 An ink was prepared in the same manner as in Example 1 except that 50 parts of wheat starch was used instead of polyethylene fine particles in the preparation of the ink. As compared with Example 1, the viscosity of the ink during preparation was large and the printing of the ink was impossible.

Comparative Example 3 Fine particles of an ethylene / acrylic acid copolymer having an average particle size of 10 μm (trade name: FlowBeads EA-209, manufactured by Sumitomo Seika) instead of polyethylene fine particles in the preparation of ink.
Ink was prepared in the same manner as in Example 1 except that 50 parts were used. The prepared ink could not be printed.

Comparative Example 4 In the preparation of the ink, the polyethylene fine particles had an average particle size of 6
μm fine particles (trade name: FlowBeads LE-1080,
An intermediate sheet for a pressure-sensitive copying sheet was prepared in the same manner as in Example 1 except that 50 parts by Sumitomo Seika Co., Ltd.) was used.

Comparative Example 5 In the preparation of the ink, the polyethylene fine particles had an average particle size of 4
Ink was prepared in the same manner as in Example 1 except that 50 parts of 0 μm particles (trade name: Flow beads 40 μm, manufactured by Sumitomo Seika) were used. The ink could not be mixed sufficiently with three rolls and could not be used as ink.

Comparative Example 6 An intermediate sheet for a pressure-sensitive copying sheet was prepared in the same manner as in Example 7 except that polyethylene particles were not mixed in the ink preparation.

Comparative Example 7 An ink was prepared in the same manner as in Example 7 except that 50 parts of wheat starch granules were used instead of polyethylene fine particles in the ink preparation. As compared with Example 7, the viscosity increased during the preparation of the ink and printing of the ink was impossible.

Comparative Example 8 Fine particles of an ethylene / acrylic acid copolymer having an average particle size of 10 μm (trade name: FlowBead EA-209, manufactured by Sumitomo Seika Chemicals Co., Ltd.) instead of polyethylene fine particles in the preparation of ink
Ink was prepared in the same manner as in Example 7 except that 50 parts were used. The prepared ink could not be printed.

Comparative Example 9 In the preparation of ink, the polyethylene fine particles had an average particle size of 6
μm fine particles (trade name: FlowBeads LE-1080,
A medium-use sheet for pressure-sensitive copying sheet was prepared in the same manner as in Example 7 except that 30 parts of Sumitomo Seika Co., Ltd.) was used.

Comparative Example 10 Polyethylene fine particles having an average particle size of 4 were prepared in the ink preparation.
An ink was prepared in the same manner as in Example 7, except that 30 parts of 0 μm particles (trade name: Flow beads 40 μm, manufactured by Sumitomo Seika) were used. In the ink, polyethylene fine particles immediately settled and the stability was poor.

The colored stains produced during the production and the colored stains caused by friction of the pressure-sensitive copy sheets obtained in Examples and Comparative Examples were evaluated. This is shown in Table 1. [Evaluation of Color Formability] A slip is prepared by using two medium-use sheets for pressure-sensitive copy sheets prepared in the examples and comparative examples as one set. Next, drop-type color tester (weight: 150
(g, height: 20 cm), the recorded image developed on the second color developing surface was measured for color density one day after the pressing with a Macbeth reflection densitometer.

[Evaluation of color stains during printing] The color stains on the developed surface of the intermediate sheets for pressure-sensitive copying sheets prepared in Examples and Comparative Examples were evaluated. (Evaluation Criteria) ○: Good, Δ: Inferior, ×: Not practical.

[Evaluation of Rub Resistance] Two sheets of each of the intermediate sheets for pressure-sensitive copying sheets prepared in the examples and comparative examples were made into one set by superposing the capsule surface and the color developing surface, and under a pressure of 100 g / cm ² After 5 reciprocations, the surfaces were rubbed against each other, and the color stain developed on the color developing surface was visually evaluated, and this was evaluated as the abrasion resistance of the pressure-sensitive copy sheet. (Evaluation Criteria) ○: Good, Δ: Inferior, ×: Not practical.

[Evaluation of pressure resistance] Two sheets of each of the pressure-sensitive copying sheet intermediate sheets prepared in Examples and Comparative Examples were made into a set by overlapping the capsule surface and the color developing surface, and the basis weight was 64 g /
After sandwiching each of m ² of high quality paper from above and below and applying a pressure of 20 kg / cm ² for 1 minute, the color stain on the color developing layer surface of the color developing sheet was visually evaluated. (Evaluation Criteria) ○: Good, Δ: Inferior, ×: Not practical.

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[Table 1]

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As is apparent from the results of Table 1, the pressure-sensitive copying sheet using the pressure-sensitive copying capsule ink obtained in the present invention is excellent in color development and has less pressure stain and friction stain. In addition, there is little capsule breakage during ink preparation or pressure-sensitive copying sheet production.

Claims (2)

[Claims] 1. A capsule ink for pressure-sensitive copying, which comprises a microcapsule containing an electron-donating color former, an ultraviolet-curable compound and a photopolymerization initiator as basic components, and contains at least one kind of polyethylene fine particles and polyurethane fine particles in the ink. Capsule ink for pressure-sensitive copying characterized by 2. The capsule ink for pressure-sensitive copying according to claim 1, which is for letterpress printing.