JPH0259781B2 - - Google Patents

Description

Detailed Description of the Invention "Industrial Application Field" The present invention relates to a pressure-sensitive copying sheet, and more particularly to a sheet having a coating layer of inked capsules, and a receiving layer that develops color by receiving capsule oil from the coating layer. The present invention relates to an improvement in a pressure-sensitive copying sheet constructed by combining sheets having the following properties.

"Prior art" Electron-donating color formers such as crystal violet lactone and benzoyl leucomethylene blue,
A combination with an electron-accepting color developer such as activated clay, a phenol-formaldehyde condensate, or a polyvalent metal salt of an aromatic carboxylic acid, or a combination of a nickel carboxylic acid salt and N,N'-di-benzyl-di-thio-oxamide. Pressure-sensitive copying sheets that utilize the principle of color development through the reaction of various chromogen substances, such as combinations of organic iron phosphates, metal salts such as lauryl gallate, and ligand compounds, are well known. .

Generally, such pressure-sensitive copying sheets are manufactured using a phase separation process.
Top paper (CB) in which microcapsules containing a chromogen substance prepared by interfacial polymerization method, in-situ method, etc. are coated on a support, and another chromogen that reacts with the above chromogen substance to develop color. A bottom sheet (CF) in which a chromogen substance is applied to a support, and a middle sheet (CFB) in which the above microcapsules and chromogen substance are applied to separate sides of the support.
are used in combination as appropriate.

In addition, there is also a so-called single pressure-sensitive copying sheet in which the above-mentioned microcapsules and chromogen material are coated as a laminated or mixed layer on the same side of a support, and a capsule layer is further coated on the back side of the single pressure-sensitive copying sheet. There is also a single pressure-sensitive copying sheet set in which the above-mentioned lower paper and inner paper are appropriately combined.

Normally, these pressure-sensitive copying sheets are manufactured by applying water-based paint to a support using a large coating machine, but in a special manufacturing method, the capsules are made into ink and then coated with a printing machine. There is a way to spot print.

Capsule ink spot printing allows expensive capsule paint to be printed only on the necessary areas of the support, so it is more flexible than the method of applying water-based paint to the entire surface of the support using a large coating machine. Depending on the variety, it exhibits extremely excellent economic characteristics. However, since the coating is applied to the support by a special method of printing, the amount of capsules coated tends to be small, and the resulting pressure-sensitive copying sheet has the disadvantage that the coloring properties are reduced.

"Problems to be Solved by the Invention" An object of the present invention is to eliminate the above-mentioned drawbacks and provide a pressure-sensitive copying sheet that has excellent color development even when a capsule ink is applied to a support. That's true.

"Means for Solving the Problems" This object of the present invention is achieved by incorporating encapsulated oil into a receptor layer that develops color by receiving capsule oil from a capsule ink coating layer.

The present invention provides a pressure-sensitive copying sheet composed of a combination of a sheet having a capsule ink coating layer and a sheet having a receptor layer that develops color by receiving capsule oil from the capsule ink coating layer.
A pressure-sensitive copying sheet characterized in that the receptor layer contains encapsulated oil.

"Function" Examples of the chromogen substance used in the present invention include a combination of an electron-donating color former and an electron-accepting color developer, or a combination of a metal salt and a ligand compound.

Examples of the electron-donating coloring agent include the following substances that are known in the field of pressure-sensitive copying paper.

3,3-bis(p-dimethylaminophenyl)
-6-dimethylaminophthalide, 3-(p-dimethylaminophenyl)-3-(1,2-dimethylindol-3-yl)phthalide, 3,3-bis(1,2-dimethylindole-3- )-5-
triallylmethane dyes such as dimethylaminophthalide, 3,3-bis(9-ethylcarbazol-3-yl)-6-dimethylaminophthalide,
Diphenylmethane dyes such as 4,4'-bis-dimethylaminobenzhydryl benzyl ether, N-halophenyl-leucoauramine, N-2,4,5-trichlorophenylleucoauramine, benzoylleucomethylene blue, p-nitro Thiazine dyes such as benzoylleucomethylene blue, 3-methyl-spiro-dinaphthopyran, 3-
Spiro dyes such as phenyl-spiro-dinaphthopyran, 3-propyl-spiro-dibenzopyran,
Lactam dyes such as rhodamine-B-anilinolactam, rhodamine (p-nitroanilino) lactam, 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-phenylaminofluorane, 3-piperidino-6-methyl-7-phenylaminofluorane, 3-diethylamino-
Fluoran dyes such as 6-methyl-7-xylidinofluorane and mixtures thereof.

Examples of the electron-accepting color developer include the following substances known in the field of pressure-sensitive copying paper.

Clays such as acid clay, activated clay, attapulgite, zeolite, and bentonite, phenolic resins, polyvalent metal salts of various aromatic carboxylic acids as described in Japanese Patent Publication No. 51-25174, and polyvalent metal salts of various aromatic carboxylic acids as described in JP-A-54-106316. Zinc salts of 2,2'-bisphenolsulfone compounds, etc., and mixtures thereof.

Examples of the combination of a metal salt and a ligand compound include the following combinations of substances known in the field of pressure-sensitive copying paper.

Nickel stearate and N,N'-di-benzyl-dithio-oxamide, Nickel laurate and α-benzylglyoxime, Tricaprylmethylammonium vanadate and Dodecylamine 8-hydroxyquinolinesulfonate, Benzyl lauryl molybdate. Dimethylammonium and lauryl protocatechylate, titanium stearate and lauryl gallate, iron naphthenate and benzyl gallate, polypherophenylmethylsiloxane and methylenebis(8-oxyquinoline), copper palmitate and N,N'-bis-2- octanoyloxyethyldiethyldithiooxamide, cobalt laurate and di-o-tolylguanidine, hinokitiol and polyvanadophenylmethylsiloxane, organic iron phosphate and lauryl gallate as described in JP-A-58-38191, etc. combinations and mixtures thereof.

When chromogenic substances such as those mentioned above are microencapsulated, the chromogenic substances are usually encapsulated in a state dissolved in oil.
For example, the following materials which are known in the field of pressure-sensitive copying paper are exemplified.

Vegetable oils such as cottonseed oil, mineral oils such as kerosene, paraffin, naphthenic oil, chlorinated paraffin, alkylated biphenyl, alkylated terphenyl,
Aromatic hydrocarbons such as alkylated naphthalene, diarylethane, triarylmethane, diphenylalkane, alcohols such as oleyl alcohol, tridecyl alcohol, benzyl alcohol, 1-phenylethyl alcohol, glycerin, and oleic acid. Organic acids, dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate, dioctyl phthalate, diethyl adipate, propyl adipate, di-n adipate
- Esters such as butyl, dioctyl adipate, organic phosphorus compounds such as tricresyl phosphate, tributyl phosphate, tributyl phosphite, tributyl phosphine oxide, phenyl cellosolve, benzyl carbitol, polypropylene glycol, propylene glycol monophenyl Ethers such as ether, N, N-
Amides such as dimethyl lauramide, N,N-dimethylstearamide, N,N-dihexyl octylamide, ketones such as diisobutyl ketone and methylhexyl ketone, ethylene carbonate,
Alkylene carbonates such as propylene carbonate, etc., and mixtures thereof.

As the encapsulation method, conventionally known coacervation method, interfacial polymerization method, in-situ method, etc. can be selected and used as appropriate, but it is preferable to use synthetic resin as the wall material. It is particularly preferable to use a melamine formaldehyde resin capsule as described in No. 59-23698, since a pressure-sensitive copying sheet having better performance can be obtained. Note that these microcapsules can also contain antioxidants, ultraviolet absorbers, etc., if necessary.

The thus obtained microcapsule dispersion containing the chromogen substance can be used as the prepared dispersion,
Alternatively, after passing through a concentration process such as filtration, most of the material is removed by means such as ventilation drying, surface drying, fluidized drying, flash drying, spray drying, vacuum drying, freeze drying, infrared drying, high frequency drying, ultrasonic drying, finely pulverized drying, etc. The dispersion medium is removed to form powder capsules. Then, it is dispersed in a non-aqueous medium to prepare a non-aqueous microcapsule ink.

In addition, as described in JP-A-53-135718, after mixing the aqueous capsule dispersion and the non-aqueous medium,
A non-aqueous capsule ink can also be prepared by a method in which the aqueous medium is removed under reduced pressure, a method in which the capsule dispersion is filtered and then replaced with a non-aqueous medium, and the like.

In the present invention, when dispersing capsules containing a chromogen substance in an ink medium, a surfactant can be used if necessary, and examples of the surfactant include the following substances.

Sodium alkyl sulfate, sodium alkylbenzene sulfonate, sodium alkylnaphthalene sulfonate, sodium polystyrene sulfonate, sodium lignin sulfonate,
Anionic activators such as sodium oleate amide sulfonate, sodium dialkyl sulfosuccinate, sulfated castor oil, dialkyl phosphate ester, alkyl phosphate ester, diaryl phosphate ester, aryl phosphate ester; halogenated trimethylaminoethyl alkylamide, Cation activators such as alkylpyridinium sulfates and alkyltrimethylammonium halides; polyoxyethylene alkyl ethers, polyoxyethylene fatty acid esters, polyoxyethylene alkyl phenyl ethers, polyhydric alcohol fatty acid esters, polyoxyeritin polyhydric alcohol fatty acids Nonionic surfactants such as esters and sucrose fatty acid esters; amphoteric surfactants such as alkyltrimethylaminoacetic acid, alkyldiethylenetriaminoacetic acid, lecithin, etc., and mixtures thereof.

Furthermore, in the ink medium, resin,
Capsule protectants, white pigments, desensitizing components, ultraviolet absorbers, antioxidants, fluorescent dyes, plasticizers, etc. can also be added.

Examples of the resin include the following substances.

Rosin (gum rosin, oil rosin, tall oil rosin), natural resins such as shellac, copal, dalman, gilsonite, zein, hardened rosin, ester gum and other rosin esters, maleic acid resin, fumaric acid resin, dimerized rosin, polymerized rosin , rosin-modified phenolic resin, methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, ethylhydroxyethylcellulose, carboxymethylcellulose, cellulose acetate propionate, cellulose acetate butyrate, semi-synthetic resins such as nitrocellulose, phenolic resin, xylene resin, urea Resin, melamine resin, ketone resin, coumaron/indene resin, petroleum resin, terpene resin, cyclized rubber, chlorinated rubber, alkyd resin, polyamide resin, acrylic resin, polyvinyl chloride,
Vinyl chloride/vinyl acetate copolymer, polyvinyl acetate, ethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, methyl vinyl ether-maleic anhydride copolymer, isobutylene-
Synthetic resins such as maleic anhydride copolymer, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl butyral (butyral resin), polyvinylpyrrolidone, chlorinated polypropylene styrene resin, epoxy resin, polyurethane, and mixtures thereof. These resins are selected and used as appropriate depending on the type of ink medium used, but the method of use is, for example, the method disclosed in "Printing Ink Technology" (CMC Company Edition) etc. should be adopted.

Examples of the capsule protectant include cellulose powder, starch particles, microspheres, glass beads, and synthetic resin powder.

Desensitizing components include various amino compounds in the case of leuco-based recording materials, and organic phosphorus-based compounds as described in JP-A-59-38089 in the case of iron and chelate-based recording materials. or a compound having an aminocarboxylic acid group.

Examples of white pigments include oxides, hydroxides, carbonates, sulfates, halogen compounds such as aluminum, zinc, magnesium, calcium, and titanium, as well as acid clay, activated clay, attapulgite, zeolite, bentonite, kaolin, calcined kaolin, etc. Examples include organic pigments such as clays, melamine resins, and urea resins.

Examples of the ink medium used in the present invention include various media known in the printing industry. For flexographic and gravure inks,
Benzene, toluene, xylene, cyclohexane, hexane, ligroin, methyl isobutyl ketone, methyl acetate, ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol and the like are preferred. In particular, low-boiling alcohols such as methanol and ethanol are most preferably used, to which a small amount of n-propyl alcohol, isopropyl alcohol, or water may be added to control the drying properties of the ink, or methyl acetate, ethyl acetate, butyl acetate, Methyl cellosolve, ethyl cellosolve, etc. are added.

In the case of flexo type and gravure type inks, a resin is added as a binder, and as the resin, the above-mentioned resins are used. Among them, polyvinyl acetate, vinyl chloride/vinyl acetate copolymer, ethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, methyl vinyl ether-maleic anhydride copolymer, isobutylene-
Preferred are maleic anhydride copolymer, modified polyvinyl alcohol, polyvinyl butyral, polyvinylpyrrolidone, ethylcellulose, nitrocellulose, hydroxypropylcellulose, cellulose acetate propionate, cellulose acetate butyrate, and the like.

Waxes are mainly used as the medium for hot melt inks. As this wax type,
Animal-based waxes such as beeswax, spermaceti wax, and lanolin; plant-based waxes such as candelilla wax, carnauba wax, wood wax, rice wax, and sugarcane wax; mineral-based waxes such as montan wax, ozokerite, and lignite wax. ,
Petroleum-based waxes such as paraffin wax and microcrystalline wax, modified waxes such as montan wax derivatives, paraffin wax derivatives, and microcrystalline wax derivatives, hydrogenated waxes such as Castor wax and opal wax, and low molecular weight polyethylene. and its derivatives, synthetic waxes such as acra wax, distearyl ketone, caproic acid amide, caprylic acid amide,
pelargonic acid amide, capric acid amide, lauric acid amide, tridecylic acid amide, myristic acid amide, stearic acid amide, behenic acid amide, ethylene bisstearic acid amide, caproleic acid amide, oleic acid amide, linoleic acid amide, ricinoleic acid amide, Fatty acid amide waxes such as linolenic acid amide, fatty acid waxes such as stearic acid and behenic acid, alcohol waxes such as stearyl alcohol, phosphate ester waxes such as distearyl phosphate ester, etc. are used singly or in combination. .

Among them, oxidized mineral waxes such as Montan wax, amide waxes such as ethylene bisstearamide, stearamide, behenic acid amide, fatty acid waxes, phosphate ester waxes, and mixtures thereof, with a penetration hardness of 0.1 to 30, Those having a melting point of 50°C to 160°C and a melting range of less than 20°C are preferably used.

In addition to the waxes listed above, we also offer
It is also possible to use an aromatic hydrocarbon compound having a temperature range of 0.degree.

A good system can also be obtained by using an aromatic hydrocarbon compound and a wax in combination, but in that case it is desirable to use a resin in the mixed system.

Specifically, aromatic hydrocarbon compounds include:
2,6-diisopropylnaphthalene, 1,4,5
-trimethyl-naphthalene, 2,3,5-trimethyl-naphthalene, 2,3-dimethylnaphthalene, 1,3,6,8-tetramethylnaphthalene,
1,2-di-o-tolylethane, bis-(2,4,
5-trimethylphenyl)methane, 1,18-diphenyl-octadecane, 1,3-terphenyl,
1,2-di-p-tolylethane, diphenyl-p
-tolylmethane, 1,2-dibenzylbenzene,
3,4-diphenylhexane, 1,2-bis(2,3-dimethylphenyl)ethane, 4,4'-
Isopropylidene diphenol, bisresorcinol ethylene ether, 4-tert-butyl-phenyl salicylate, 2,2-bis(4-acetoxyphenyl)propane, bis(4-acetoxyphenyl)sulfone, terephthalic acid dimethyl ether, Terephthalic acid dichlorophenyl ester, terephthalic acid distearylamide, malonic acid ethyl ester 4-methoxyanilide, benzyl mandelate, benzoic acid phenyl ester, benzoic acid 2-naphthyl ester, 2-hydroxy-
Examples include 3-octylcarbamoylnaphthalene, benzyl 4-hydroxybenzoate, benzyl p-benzyloxybenzoate, 1,4-bispropionyloxybenzene, and 1,1-dibenzoylmethane.

Examples of the resin include the resins mentioned above,
Among them, hardened rosin, ester gum, ethyl cellulose, phenolic resin, rosin-modified phenolic resin, urea/melamine resin, chlorinated rubber, cyclized rubber,
Maleic acid resin, petroleum resin, terpene resin, etc. are preferably used.

Examples of the medium for electron beam or ultraviolet curable ink include compounds having one or more, preferably a plurality of vinyl or vinylidene groups, such as acryloyl groups, methacryloyl groups, allyl groups, unsaturated polyesters, vinyloxy, acrylamide groups, etc. A reaction product of a polyol, polyamine or amino alcohol, etc. with an unsaturated carboxylic acid,
Examples include reaction products of acrylate or methacrylate having a hydroxy group and polyisocyanate.

Typical 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 methacrylic acid, pentaerythritol and acrylic acid, condensation product of maleic acid, diethylene glycol and acrylic acid, methyl methacrylate , butyl methacrylate, styrene, etc. Regarding these monomers, please refer to JP-A-49-52889, JP-A No. 48-68641, JP-A No. 48-
It is also possible to select from those disclosed in Japanese Patent Publication No. 32586, Japanese Patent Publication No. 49-7115, etc.

In the case of curing by ultraviolet rays, it is preferable to add a photopolymerization initiator to the medium, and for example, photopolymerization initiators such as aromatic ketones, quinone compounds, ether compounds, and nitro compounds are used.

Specifically, benzoquinone, phenanthrenequinone, naphthoquinone, diisopropylphenanthrenequinone, benzoisobutyl ether, benzoin, furoinbutyl ether, Michler's ketone,
Examples include photopolymerization initiators such as Michler's thioketone, fluorenone, trinitrofluorenone, and β-benzoylaminonaphthalene.

As a medium for oxidative polymerization type (letterpress type) ink,
Oils are used, and if necessary, solvents, wax,
Dryers, thickeners, gelling agents, thixotropic agents, etc. are added.

Oils include vegetable oils (drying oils such as linseed oil and sunflower oil, semi-drying oils such as soybean oil, non-drying oils such as castor oil), processed oils (dehydrated castor oil, polymerized oils,
Maleated oil, vinylated oil, urethanized oil), mineral oil (machine oil, spindle oil), etc.

As a solvent, high boiling point petroleum solvent (ink oil), diethylene glycol monobutyl ether,
Examples include diethylene glycol monobutyl ether acetate.

The microcapsule ink containing the chromogen substance thus prepared is coated on a suitable support such as paper, synthetic fiber paper, synthetic resin film, etc. according to various printing methods.

The amount of capsule ink applied is adjusted appropriately depending on the type of ink prepared, and is not particularly limited, but is generally 0.3 to 10 g/
It is adjusted within the range of about m ² , preferably about 1 to 5 g/m ² .

The pressure-sensitive copying sheet of the present invention is constructed by combining a sheet having a capsule ink coating layer prepared in this way and a sheet having a receptor layer that develops color by receiving capsule oil from the capsule ink coating layer. However, the receptor layer contains an oil capsule containing no chromogen substance.

The chromogen substance forming the receptor layer is pulverized using a ball mill, attritor, sand mill, etc., if necessary, and then crushed into capsules of oil that does not contain the above-mentioned chromogen substance, a commonly used white pigment, binder, and if necessary, a dispersant,
It is prepared as a coating liquid by using various auxiliary agents such as colored dyes, optical brighteners, ultraviolet absorbers, antioxidants, and antifoaming agents.

The amount of oil capsules that do not contain a chromogen substance added to the receptor layer is not particularly limited as long as the coloring property is improved, but generally 0.5% of the solid content in the receptor layer is added. ~50% by weight,
It is preferably adjusted within a range of about 3 to 30% by weight.

As for the white pigment, dispersant, etc., those of the same kind as those exemplified as substances added to the capsule ink coating layer are appropriately selected and used.

As the binder, various types of binders such as water-soluble or latex type binders are used.

Examples of water-soluble binders include proteins such as gelatin, albumin, and casein, grain starch, and
Starches such as modified starch, oxidized starch, etherified starch, and esterified starch; celluloses such as carboxymethyl cellulose and hydroxyteethyl cellulose; water-soluble natural polymer compounds such as agar, sodium alginate, and sutucaroses such as gum arabic; polyvinyl alcohol; , polyvinylpyrrolidone, sodium polyacrylate, polyacrylamide, maleic acid copolymer salts such as vinyl acetate-maleic anhydride sodium salt, styrene-maleic anhydride ammonium salt, butadiene-methacrylic acid sodium salt, etc. Examples include synthetic polymer compounds.

Examples of the latex binder include styrene-butadiene latex, acrylonitrile-butadiene latex, acrylic ester latex, vinyl acetate latex, methyl methacrylate-butadiene latex, and carboxy-modified (for example, acrylic acid) latexes thereof.

The receptive layer forming coating solution thus prepared is coated with various coating methods as described above using various known coating methods such as an air knife coater, a roll coater, a blade coater, a size press coater, a curtain coater, a bill blade coater, and a short dwell coater. applied onto a support.

The coating amount of the receptive layer forming coating liquid is appropriately adjusted depending on the type of coating liquid prepared, etc., and is not particularly limited, but is generally about ² to 15 g/m2, preferably about 3 to 15 g/m2. It is adjusted within a range of ^about 7g/m2.

"Examples" In order to make the effects of the present invention even clearer, Examples and Comparative Examples are listed below, but the present invention is not limited to these Examples.
In addition, unless otherwise specified, parts and % in the examples represent parts by weight and % by weight, respectively.

Example 1 [Preparation of microcapsules containing a ligand compound] 25 parts of lauryl gallate and N,N-dibenzyl-
Add 5 parts of β-aminoethanol to adipic acid di-n
- A methoxymethylolated melamine initial condensate (trade name Cymel
350 (manufactured by Mitsui Toatsu Chemical Co., Ltd.) was added and mixed in a solid content of 62 parts to obtain an internal phase liquid.

Separately, in a stirring mixing container equipped with a heating device, 2 parts of ethylene-maleic anhydride copolymer (trade name EMA-31, manufactured by Monsanto) as an emulsifier and 2 parts of ethylene-maleic anhydride polymer copolymer (trade name
Add an aqueous solution prepared by heating and dissolving 0.3 parts of EMA-81 (manufactured by Monsanto) in 200 parts of water, and add 5 parts of
% caustic soda aqueous solution was added to adjust the pH to 4.0 to obtain an aqueous medium for capsule production.

This aqueous medium was heated to 85°C, and the internal phase liquid was emulsified and dispersed therein so that the average particle size was 7.0 μm, and then reacted at 85°C for 3 hours.

Next, 0.2N acetic acid was gradually added to this system while stirring to adjust the system pH to 4.2, and then further
Add 0.05N hydrochloric acid gradually over 3 hours to cool the system.
The pH was adjusted to 3.5. Next, the temperature of the system was raised to 95°C, and the mixture was reacted at 95°C for 5 hours to obtain a microcapsule dispersion containing a ligand compound.

[Preparation of powder capsules] 50 parts of a 10% aqueous solution of Cymel 350 was dropped into the above microcapsule dispersion at 95°C with strong stirring, and then reacted at 95°C for 1 hour to form a thickened capsule dispersion. I got the liquid. The resulting capsule dispersion was filtered under suction, and the paste was further dried to obtain powder capsules containing a mononuclear ligand compound.

[Preparation of capsule ink and creation of top paper] 30 parts of the above powder capsules were mixed with 59 parts of ethyl alcohol.
After dispersing it in a mixed solution of 5 parts and 6 parts of water, 5 parts of ethyl cellulose No. 14 (manufactured by Hercules) was added and dissolved to obtain a flexo-type capsule ink. The obtained capsule ink was printed on a 40 g/m ² base paper using a printing machine so that the amount of ink was 3 g/m ² to obtain a top paper.

[Preparation of oil-containing microcapsules] 50 parts of diethyl adipate and di-n-adipate
40 parts of Cymel 350 (solid content) was added to and mixed with 50 parts of butyl to obtain an internal phase liquid. Oil-containing microcapsules were prepared in the same manner as in the preparation of the ligand compound-containing microcapsules, except that this internal phase liquid was used.

[Preparation of the bottom sheet] To an aqueous solution prepared by adding 89 parts of t-butylbenzoic acid, 125 parts of diphenyl phosphate, and 70 parts of sodium laurylbenzenesulfonate to 800 parts of a 5% aqueous solution of caustic soda, add chloride to 500 parts of water. An aqueous solution containing 108 parts of ferric iron was added under tension stirring to form yellow fine particles, and then 500 parts of a 20% aqueous solution of sodium t-butylbenzoate was added to the dispersion.
Furthermore, 25 parts of TiCl ₄ was gradually added to this dispersion under strong stirring to form a pale yellow fine particle dispersion, which was then filtered and washed to obtain a slurry.

Next, add 1 part of sodium polyacrylate to 200 parts of water.
Dissolve 1 part of hydroxyethyl cellulose, add 20 parts of the above slurry in solids, and 20 parts of titanium oxide.
After adding 50 parts of aluminum hydroxide and 10 parts of tribenzylamine for strong dispersion, 15 parts of carboxy-modified styrene-butadiene copolymer latex (solid content concentration 50%) and the above-mentioned oil-containing microorganisms were added to the dispersion. A coating solution was obtained by adding 20 parts of capsules in solid form.

The obtained coating liquid was applied to a base paper of 40 g/m ² with a dry weight of 8
A base paper was obtained by applying the coating using an air knife coater so that the coating amount was 1.2 g/m ² .

When the upper paper and lower paper thus obtained were overlapped and printed using a typewriter, an extremely clear colored image was obtained.

Example 2 10 parts of tribenzylamine was added to diethyl adipate.
Cymel 350 was added as a solid to a solution obtained by dissolving 40 parts of Cymel 350 and 50 parts of di-n-butyl adipate.
40 parts were added and mixed to obtain an internal phase liquid. Oil-containing microcapsules were prepared in the same manner as in Example 1 for preparing the ligand compound-containing microcapsules, except that this internal phase liquid was used.

An upper paper and a lower paper were prepared in the same manner as in Example 1, except that 20 parts of this oil-containing microcapsule was added as a solid content instead of the oil-containing microcapsule of Example 1.

When the resulting upper paper and lower paper were overlapped and printed using a typewriter, an extremely clear colored image was obtained.

Comparative Example 1 Upper paper and lower paper were prepared in the same manner as in Example 1, except that oil-containing microcapsules were not added.

When the obtained upper paper and lower paper were overlapped and printed using a typewriter, only a colored image was obtained which was inferior in sharpness compared to Examples 1 and 2.

Example 3 [Preparation of microcapsules containing a color former] To a solution obtained by dissolving 4 parts of crystal violet lactone in 100 parts of alkylnaphthalene, 50 parts of Cymel 350 in solid form was added and mixed to obtain an internal phase liquid. Ta. Color former-containing microcapsules were prepared in the same manner as in Example 1, except that this internal phase liquid was used.

[Preparation of capsule ink] 70 parts of a 10% aqueous solution of Cymel 350 was dropped into the above microcapsule dispersion at 95°C with strong stirring, and then reacted at 95°C for 1 hour to form a thickened capsule dispersion. I got it. The resulting capsule dispersion was suction-filtered, and the paste was dried to obtain mononuclear color former-containing powder capsules.

30 parts of powder capsules were mixed and dispersed in a mixed solution of 55 parts of microcrystalline wax and 5 parts of distearyl phosphate to obtain a hot melt type capsule ink.

[Preparation of oil-containing microcapsules] 40 parts of Cymel 350 (solid content) was added to 100 parts of alkylnaphthalene and mixed to obtain an internal phase liquid. Oil-containing microcapsules were prepared in the same manner as in Example 1, except that this internal phase liquid was used.

[Preparation of inner paper] 65 parts of aluminum hydroxide, 20 parts of zinc oxide, 3,
15 parts of a blend of zinc 5-di(α-methylbenzyl)salicylate and α-methylstyrene/styrene copolymer (melt ratio 80/20), 5 parts of polyvinyl alcohol aqueous solution (solid content), and 300 parts of water 20 parts of the above oil-containing microcapsules (solid content) and 20 parts of carboxy-modified styrene-butadiene copolymer latex were added to the dispersion obtained by milling 1 part of the oil in a ball mill for 24 hours.
40 parts (solid content) of the developer coating solution prepared by adding 40 parts (solid content).
g/m ² base paper was coated with an air knife coater to give a dry weight of 5 g/m ² .

The above-mentioned hot-melt capsule ink was printed on the back side using a printing machine at an ink amount of 6 g/m ² to obtain an inner sheet.

When two sheets of the resulting inner paper were overlapped and printed using a typewriter, a clear colored image was obtained.

Comparative Example 2 An inner paper was prepared in the same manner as in Example 3, except that no oil-containing microcapsules were added.

When two sheets of the resulting inner paper were overlapped and printed using a typewriter, only a colored image was obtained that was inferior in clarity compared to Example 3.

Claims (1)

[Claims] 1. A pressure-sensitive copying sheet composed of a combination of a sheet having a capsule ink coating layer and a sheet having a receptor layer that develops color by receiving capsule oil from the capsule ink coating layer, in which the receptor layer is encapsulated with oil. A pressure-sensitive copying sheet characterized by containing.