JPH0462873B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing pressure-sensitive copying paper, and more particularly to a method for producing pressure-sensitive copying paper with good color development using microcapsule-containing ink. (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. There is. 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, it is a so-called single-piece 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.
Furthermore, there is a single pressure-sensitive copying sheet set in which a capsule layer is provided on the back side of the single pressure-sensitive copying sheet, and 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 compared to the method of applying water-based paint to the entire surface of the support using a large coating machine, for example, it is possible to print areas with different tones. It can be used in a variety of ways, such as producing copy paper, and depending on the desired product, it can be economically very advantageous. 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 of pressure-sensitive copying paper manufactured using capsule ink, and to provide a method for manufacturing pressure-sensitive copying paper with excellent color development. There is a particular thing. (Means for Solving the Problems) The present invention is characterized by forming, by printing, a microcapsule layer containing a chromogen substance on a coating layer of microcapsules that do not contain a chromogen substance. This company manufactures pressure-sensitive copying paper. (Function) In the above structure, the microcapsules that do not encapsulate a chromogen substance are microcapsules that do not encapsulate a chromogen substance but encapsulate an oil as described below, and are different from conventionally known core cell capsules. method (e.g., U.S. Pat. No. 2,800,457;
2800458, etc., interfacial polymerization method (e.g., method shown in Japanese Patent Publication No. 38-19574, Japanese Patent Publication No. 42-446, Japanese Patent Publication No. 42-771, Japanese Patent Publication No. 49-45133, etc.), in- Situ polymerization method (for example, Japanese Patent Publication No. 36-9168
Microcapsules which can be produced by methods such as those disclosed in Japanese Patent Publication No. 51-9079 and Japanese Patent Publication No. 53-84881 can be used as they are. The microcapsules obtained by these methods can be applied to a support such as paper or a sheet by air knife coating, roll coating, blade coating, etc., by a size press, or by silk screen or flexography. Alternatively, it may be printed using a method such as gravure. In the above configuration, the amount of microcapsules that do not contain a chromogen substance to be applied is 1 g/m 2 or more in order to obtain an appropriate effect, and is preferably 1 g/m ² or more from the viewpoint of effectiveness and economy.
It is in the range of 1.5 to 5 g/ ^m2 . Therefore, the microcapsules containing a chromogen substance with the above-mentioned structure are, for example, microcapsules containing an oil-based substance in which a so-called color former that causes a color reaction with a color developer is dissolved. The membrane agent for the capsule is not particularly limited, but it is made of melamine-formaldehyde resin or acrylonitrile resin in order to retain the core material in the ink medium, and the average particle size is selected from the viewpoint of the balance between friction staining and color development. It is preferable to use one with a diameter of 1 to 5 μm. Incidentally, microcapsules whose wall material is made of melamine-formaldehyde resin were disclosed in Japanese Patent Application Laid-Open No. 1983-
No. 84881, No. 54-49984, No. 55-15660, No. 55
-51431, 56-102934, 56-58536, same
No. 56-51238, No. 57-105236, No. 58-14942,
No. 59-162943, No. 59-177129, No. 59-196731
No. 59-230634 and No. 60-28819, in which a hydrophobic liquid is emulsified in the form of fine droplets in an aqueous medium containing an emulsifier, and then the aqueous medium or is obtained by condensing a melamine-formaldehyde initial condensate contained in a hydrophobic liquid under acidic heating conditions and depositing it on the surface of microdroplets of the hydrophobic liquid. In this case, the microcapsules used in the present invention include those prepared using only the melamine-formaldehyde initial condensate, as well as those prepared using other membrane materials in combination as long as the membrane quality does not change significantly. For example, it is possible to use a melamine-formaldehyde initial condensate and other aldehyde-based resin forming materials in combination. Examples of the melamine-formaldehyde initial condensate include an initial condensate obtained by condensing melamine and formaldehyde, or an alkylated or partially alkylated product thereof made using, for example, a C ₁ to C ₈ alcohol, as well as an anion thereof. Examples include cationic or nonionic modified products, among which water-soluble ones are used for aqueous media, and oil-soluble ones are used for hydrophobic liquids. Examples of anion modifiers include sulfamic acid, sulfanilic acid,
Glycolic acid, glycine, acidic sulfite, phenol sulfonate, taurine, etc.; cationic modifiers include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dimethylaminoethanol, etc.; nonionic modifiers include ethylene glycol, diethylene glycol, etc. . Other aldehyde-based resin forming materials used in combination with the melamine-formaldehyde initial condensate include:
Examples include phenol-formaldehyde resin initial condensates, aminoaldehyde initial condensates other than melamine-formaldehyde initial condensates, etc.
Examples of the phenol-formaldehyde resin initial condensate include initial compounds obtained by condensing formaldehyde with at least one phenol such as phenol, cresol, xylenol, resoncinol, hydroquinone, pyrocatechol, and pyrogallol. Examples of the aminoaldehyde resin initial condensate include at least one amine such as urea, thiourea, alkyl urea, ethylene urea, acetoguanamine, benzoguanamine, guanidine, dicyandiamide, biuret, and cyanamide, and formaldehyde, acetaldehyde, paraformaldehyde, and hexane. An initial condensate obtained by condensing at least one aldehyde such as methylenetetramine, glutaraldehyde, glyoxal, furfural, etc., or an alkyl compound or a partially alkylated product thereof prepared using, for example, a C ₁ to C ₈ alcohol; Further examples include modified anions, cations, and nonionic products thereof, among which water-soluble ones are used in the aqueous medium. Examples of the anionic, cationic, and nonionic modifier include those mentioned above. The amount of the melamine-formaldehyde initial condensate as described above depends on the type of hydrophobic core material used,
It depends on the type and amount of other aldehyde-based resin-forming materials used in combination, the particle size of the capsule, the purpose of the printed matter, etc., and it cannot be determined unconditionally, but from the viewpoint of core substance retention and color development, hydrophobic It is preferably 3 parts by weight or more and 5 parts by weight or less, particularly preferably 5 parts by weight or more and 30 parts by weight or less in terms of melamine, based on 100 parts by weight of the sex core substance. In addition, the amount of the aldehyde-based resin forming material used in combination with the melamine-formaldehyde initial condensate varies depending on the type of hydrophobic core substance used, the intended use of the printed material, etc., and cannot be determined unconditionally. It is necessary to use it within a range that does not deteriorate the properties of the condensate, and it is preferably 80 parts by weight or less, particularly 20 parts by weight or less, based on 100 parts by weight of the condensate. The microcapsules used in the present invention are characterized by being made of a melamine-formaldehyde resin film, but it is particularly preferable to form a hydrophobic core material by condensing a melamine-formaldehyde initial condensate contained in an aqueous medium. JP-A-60-7935 obtained by reacting an oil-soluble melamine-formaldehyde initial condensate, other aldehyde-based resin shape-forming materials as described above, or polyvalent isocyanate compounds deposited on the surface and simultaneously contained in the core material. No., or JP-A-56-
Double-walled membrane type microcapsules such as those described in No. 115371 are preferably used, and among them, a preparative oil-soluble melamine-formaldehyde initial condensate or other aldehyde-based resin-forming material is preferably used. Note that when a polyvalent isocyanate compound is used in combination, the hydrophobic liquid containing the polyvalent isocyanate compound is emulsified in the form of microdroplets in an aqueous medium containing an emulsifier, and then the melamine-formaldehyde initial condensate is added to the aqueous medium. melamine-formaldehyde resin is deposited on the surface of the microdroplets by condensation under acidic heating conditions, then the system is made alkaline, and if necessary, polyvalent amines, polyhydric alcohols, etc. are added to form the polyvalent isocyanate. By reacting with a compound, polyurethane,
It forms a urea film. As the emulsifier used in the preparation of microcapsules in the present invention, anionic, nonionic, cationic, or amphoteric polymer or low-molecular emulsifiers can be used. Examples of anionic polymers include natural polymers such as gum arabic, carraginal, and sodium alginate; semi-synthetic polymers such as carboxymethyl cellulose, cellulose sulfate, phosphorylated starch, and lignin sulfonic acid; and maleic anhydride (hydrolyzed copolymers, acrylic acid-based, methacrylic acid-based or crotonic acid-based polymers and copolymers, vinylbenzenesulfonic acid-based or 2-acrylamido-2-methyl-propanesulfonic acid-based polymers; Synthetic polymers such as copolymers, partial amides or partial esters of such polymers, copolymers, carboxy-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol, phosphoric acid-modified polyvinyl alcohol, phosphoric acid-modified polyvinyl alcohol, etc. It will be done. More specifically, examples of maleic anhydride-based (including hydrolyzed) copolymers include ethylene-maleic anhydride copolymers, styrene-maleic anhydride copolymers, and the like. Examples of the acrylic acid-based copolymer, methacrylic acid-based polymer, or crotonic acid-based copolymer include methyl acrylate-acrylic acid copolymer (hereinafter abbreviated as "copolymer"), ethyl acrylate-acrylic acid,
Examples include copolymers such as methyl acrylate-methacrylic acid, methyl methacrylate-acrylic acid, and vinyl acetate-crotonic acid. Examples of vinylbenzenesulfonic acid-based or 2-acrylamide-2-methyl-propanesulfonic acid-based copolymers include methyl acrylate-vinylbenzenesulfonic acid (or salt thereof) copolymer, vinylpyrrolidone-2-acrylamide-2 -Methyl-propanesulfonic acid copolymer and the like. Examples of nonionic polymers include semi-synthetic polymers such as hydroxyethylulose and methylcellulose, and synthetic polymers such as polyvinyl alcohol.
Examples of cationic polymers include cation-modified polyvinyl alcohol, and examples of amphoteric polymers include gelatin. Examples of low-molecular emulsifiers include sodium vinylsulfonate, sodium benzenesulfonate, sodium p-vinylbenzenesulfonate, sodium naphthalene-α-sulfonate, sodium diphenylphosphate, sodium phenylphosphonate, di-n
-Sodium butyl phosphate and the like. The emulsifier as described above is preferably contained in an aqueous medium in an amount of 0.5% or more, and more preferably 1% or more from the viewpoint of ease of preparing an emulsion and stabilization of the emulsion. The upper limit of the amount used is determined by the viscosity of the system, the capsule preparation equipment, etc., but is generally kept at 20% or less. In order to maintain the reaction system acidic during the preparation of the microcapsules used in the present invention, aminoaldehyde resins such as formic acid, acetic acid, citric acid, oxalic acid, p-toluenesulfonic acid, hydrochloric acid, sulfuric acid, etc. A so-called acid catalyst commonly used in the field is used. The reaction conditions for preparing the microcapsules used in the present invention depend on the type of melamine-formaldehyde initial condensate used, the type of other aldehyde resin forming materials used in combination, the type of polyvalent isocyanate compound, or the type of printed matter. It varies depending on the purpose and is not limited to this, but
Preferably PH5.0 or lower, 50℃ or higher, more preferably PH4.5 or lower, 70℃ or higher, particularly preferably PH3.8
Hereinafter, the temperature is preferably 75° C. or higher, and the temperature is preferably maintained under that condition for 1 hour or more, particularly 3 hours or more. In addition, microcapsules whose wall membrane material is made of acrylonitrile resin are disclosed in Japanese Patent Application Laid-Open No. 61-40187,
It is obtained by the method described in Nos. 61-40188 and 61-40189, in which a hydrophobic liquid is emulsified in the form of microdroplets in an aqueous medium containing an emulsifier, and then contained in the hydrophobic liquid. It is obtained by polymerizing an acrylonitrile monomer and depositing it on the surface of a microdroplet of a hydrophobic liquid. In this case, the microcapsules used in the present invention include those prepared using only acrylonitrile monomers, as well as those prepared using other membrane agents in combination as long as the membrane quality does not change significantly. Examples of acrylonitrile monomers include acrylonitrile, methacrylonitrile, β,β-dimethylacrylonitrile, and crotonitrile. Examples of other polymerizable monomers used in combination with acrylonitrile monomers include amide monomers, ester monomers, and aromatic monomers. Examples of amide monomers include acrylamide, methacrylamide, N-methylolacrylamide, N- Examples include methylolmethacrylamide, crotonamide, maleic acid amide, itaconic acid amide, and the like. Examples of ester monomers include acrylic esters, methacrylic esters, ethyl acrylic esters, maleic diesters, crotonic esters, and examples of esters include lower alkyl esters,
For example, methyl, ethyl, n-propyl, iso-
Propyl, t-butyl ester, etc. are preferred. Examples of aromatic monomers include styrene,
Examples include divinylbenzene and methylstyrene. Furthermore, it is possible to increase the film strength by crosslinking with a crosslinking agent. Examples of crosslinking agents include N,N-methylenebisacrylamide, triacryl formal, polyvalent metal salts of acrylic acid or methacrylic acid, etc. Preferred metals include Mg, Cu, and Zn. Further, it is preferable to carry out the polymerization using a radical initiator, particularly an azo radical initiator, and it is preferable to carry out the polymerization at a temperature of 40° C. or higher. The amount of the acrylonitrile monomer mentioned above varies depending on the type of hydrophobic core material used, the type and amount of other polymerizable monomers used together, the capsule particle size, the purpose of the printed material, etc., and cannot be determined in general. However, from the viewpoint of core material retention and color development, it is preferable to use 20 parts by weight or more of the acrylonitrile monomer per 100 parts by weight of the hydrophobic core material, particularly preferably 30 parts by weight or more and 120 parts by weight or less. In addition, the amount of other polymerizable monomers used in combination with the acrylonitrile monomer varies depending on the type of hydrophobic core material used, the purpose of the printed material, etc., and cannot be determined unconditionally, but 100 parts by weight of the acrylonitrile monomer On the other hand, it is more preferably 50 parts by weight or less, particularly 40 parts by weight or less. 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-octa Noyloxyethyldiethyldithiooxamide, cobalt laurate and di-o-tolylguanidine, hinokitiol and polyvanadophenylmethylsiloxane, JP-A-Sho
A combination of organoiron phosphate and lauryl gallate described in No. 58-38191, and a mixture 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. The capsule ink composition used in the present invention is
For example, a microcapsule dispersion prepared in an aqueous system is directly dispersed in a non-aqueous medium. Alternatively, after passing through a concentration step such as vacuum concentration or filtration, it is dispersed in a non-aqueous medium. Alternatively, after passing through a concentration step such as vacuum concentration or filtration, it is washed with a water-miscible solvent and dispersed in a non-aqueous medium. Or air drying, surface drying, fluidized drying, flash drying, spray drying,
Vacuum drying, freeze drying, infrared drying, high frequency drying,
After forming powder capsules by ultrasonic drying, pulverization drying, etc., they are dispersed in a non-aqueous medium, or as described in JP-A-53-135718, an aqueous capsule dispersion and a non-aqueous medium are mixed. After that, the aqueous medium is removed under reduced pressure. In addition, in order to obtain ink with good quality dispersion, the capsules are
It is preferable to use a capsule dispersion that has been prepared and further treated with an aldehyde resin-forming material as described in No. 238141. In the present invention, in addition to microcapsules, the non-aqueous medium may contain resins, pigments,
Capsule protective materials, surfactants, ultraviolet absorbers, antioxidants, fluorescent whitening agents, plasticizers, desensitizing ingredients, electron-donating color formers, electron-accepting color developers, ligand compounds, metal salts, etc. can also be added. The amount of microcapsules in the capsule ink composition used in the present invention varies depending on the film quality and particle size of the capsules used, the type of ink medium, and the types and amounts of other additives, and is not limited thereto. However, preferably from 3 to 100 parts by weight, more preferably from 10 to 100 parts by weight, based on 100 parts by weight of the medium.
It is 60 parts by weight. Examples of resins include rosin (gum rosin, udder rosin, tall oil rosin), shellac,
Natural resins such as copal, dammar, 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 , hydroxypropyl cellulose, ethyl hydroxyethyl cellulose, carboxymethyl cellulose, 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 Examples include synthetic resins such as maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl butyral (butyral resin), polyvinylpyrrolidone, chlorinated polypropylene styrene resin, epoxy resin, and polyurethane. These resins are appropriately selected and used depending on the type of non-aqueous medium to be used.
The method disclosed in CMC Co., Ltd. edition etc. can be adopted as appropriate. Pigments include oxides, hydroxides, carbonates, sulfates, halides of aluminum, zinc, magnesium, calcium, titanium, etc., as well as acid clay, activated clay, attapulgite, zeolite,
Examples include clays such as bentonite, kaolin, and calcined kaolin, and organic pigments such as melamine resin and urea resin. Specific examples of the capsule protective material include cellulose powder, starch powder, microspheres, glass beads, and synthetic resin powder. As surfactants, sodium alkyl sulfate, sodium alkylbenzenesulfonate, sodium alkylnaphthalenesulfonate,
Anion activators such as sodium polystyrene sulfonate, sodium oleamide sulfonate, sodium dialkyl sulfosuccinate, and sulfated castor oil; cations such as halogenated trimethylaminoethyl alkylamide, alkylpyridium sulfate, and halogenated alkyltrimethylammonium Activator: Nonionic activator such as polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, polyoxyethylene alkyl phenyl ether, polyhydric alcohol fatty acid ester, sucrose fatty acid ester; Alkyltrimethylaminoacetic acid, alkyldiethyleneaminoacetic acid, etc. Examples include amphoteric active agents. As the non-aqueous medium, those known in the printing industry can be used as appropriate, but specific examples include benzene, toluene, xylene, cyclohexane, hexane, ligroin, methyl for flexographic type and gravure type compositions. isobutyl ketone,
Examples include methyl acetate, ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, methanol, ethanol, n-propyl alcohol, isopnopylchol, n-butanol, etc.
A mixed solution of at least one selected from C ₁ or C ₂ alcohols and at least one selected from C ₃ or C ₄ alcohols, or a system in which water, the above acetate ester, the above cellosolve, etc. are further added is preferable. In the case of flexo type and gravure type compositions, a resin is added as a binder and, if necessary, a pigment is added.
Examples of this resin include the resins mentioned above, among which polyvinyl acetate, vinyl chloride/vinyl acetate copolymer, ethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, methyl vinyl ether-maleic anhydride Copolymers, isobutylene-maleic anhydride copolymers, modified polyvinyl alcohol, polyvinyl butyral, polyvinylpyrrolidone, ethylcellulose, nitrocellulose, hydroxypropylcellulose, cellulose acetate propionate, cellulose acetate butyrate, and the like are preferred. The medium for the hot-melt composition includes waxes, including animal-based waxes such as beeswax, spermaceti wax, and lanolin, candelilla wax, carnauba wax, wood wax, rice wax, and sugarcane wax. mineral waxes such as montan wax, ozokerite, lignite wax, petroleum waxes such as paraffin wax, microcrystalline wax, montan wax derivatives, paraffin wax derivatives, microstalline wax Modified wax such as derivatives, castor wax,
Hydrogenated wax such as opal wax, low molecular weight polyethylene and its derivatives, Akura wax,
Synthetic waxes such as distearyl ketone, caproic acid amide, caprylic acid amide, pelargonic acid amide, capric acid amide, lauric acid amide, tridecylic acid amide, myristylic acid amide, stearic acid amide, behenic acid amide, ethylene bisstearic acid amide, Fatty acid amide waxes such as caproic acid amide, oleic acid amide, linoleic acid amide, ricinoleic acid amide, linolenic acid amide, fatty acid based waxes such as stearic acid and behenic acid, alcohol based waxes such as stearyl alcohol, distearyl phosphate esters, etc. These phosphate ester waxes are used alone or in combination. Among them, oxidized mineral wax such as Montan wax,
Amide waxes such as ethylene bisstearamide, stearamide, and behenamide, 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, in the present invention, aromatic hydrocarbon compounds having a melting point in the range of 40°C to 200°C can be used in addition to the waxes mentioned above. It is preferable to use a resin that can be used in combination. A good system can also be obtained by using aromatic hydrocarbon compounds and waxes in combination. A more preferable system is one in which a resin is used in combination with the mixed system. Specifically, aromatic hydrocarbon compounds include:
2,6-diisopunopylnaphthalene, 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, di-chlorophenyl terephthalate ester, terephthalic acid distearylamide, malonic acid ethyl ester 4-methoxyanilide, benzyl mandelate, benzoic acid phenyl ester, benzoic acid 2-naphthyl ester, 2
-Hydroxy-3-octylcarbamoylnaphthalene, 4-hydroxybenzoic acid benzyl ester, p-benzyloxybenzoic acid benzyl, 1,
4-bispropionyloxybenzene, 1,1-
Examples include benzoylmethane. Examples of the resin include the resins listed above, among which cured rosin, ester gum, ethyl cellulose, phenolic resin, rosin-modified phenolic resin, urea, melamine resin, chlorinated rubber, cyclized rubber, maleic acid resin, petroleum resin, Terpene resins and the like are preferred. Examples of the medium for electron beam or ultraviolet curable compositions include compounds having one or more vinyl or vinylidene groups, preferably a plurality of vinyl or vinylidene groups, such as acryloyl groups, metallolyloyl groups, allyl groups, unsaturated polyesters, vinyloxy, acrylamide groups, etc. Examples include compounds that have The most typical examples include reaction products of polyols, polyamines, amino alcohols, etc. and unsaturated carboxylic acids, and reaction products of acrylates or methacrylates having hydroxyl groups and polyisocyanates. For example, typical compounds include polyethylene glycol diacrylate, propylene glycol dimethacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate,
Hexanediol acrylate, 1,2-butanediol acrylate, 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 Examples include methacrylate and styrene. Regarding these monomers, please refer to JP-A-Sho.
No. 49-52889, No. 48-68641, No. 48-32586,
You can also choose from those disclosed in Japanese Patent Publication No. 49-7115. When curing by ultraviolet light, it is preferable to add a photopolymer initiator to the medium. Examples of the photopolymer initiator include aromatic ketones, quinone compounds, ether compounds, nitro compounds, and specific examples include benzoquinone, phenanthrene quinone, naphthoquinone, diisopropylphenanthrene quinone, benzoin butyl ether, benzoin, Examples include furoinbutyl ether, Michler's ketone, Michler's thioketone, fluorenone, trinitrofluorenone, and β-benzoylaminonaphthalene. Oil is used as the medium for the oxidative polymerization type (letterpress type) composition, and a solvent, wax, dryer, thickener, gelling agent, and thixotropy agent are added as necessary. Specifically, 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,
Examples include polymerized oil, maleated oil, vinylated oil, urethanized oil), and mineral oil (machine oil, spindle oil). Specific examples of the solvent include high-boiling petroleum solvents (ink oil), diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, and the like. As the printing method used in the present invention, methods known in the art can be adopted, but
Among these, the effects of the present invention are particularly remarkable in the case of flexographic printing or gravure printing. In the present invention, it is particularly preferable to use an electron-donating coloring agent as the core substance because pressure-sensitive copying paper with extremely high coloring sensitivity can be obtained. As mentioned above, the method of the present invention relates to a method for producing a so-called transfer sheet which releases a chromogen substance from a pressure-sensitive copying paper, particularly microcapsules, and includes microcapsules that do not encapsulate a chromogen substance on a support. A coating layer is formed by coating or printing, and then a microcapsule layer containing a chromogen substance is formed on the microcapsule coating layer by printing. In such a transfer sheet, the area of the coating layer of microcapsules not containing a chromogen substance formed on the support and the area of the microcapsule layer containing a chromogen substance formed thereon are exactly the same. and when the area of the microcapsule layer encapsulating the chromogenic substance is smaller than the area of the coating layer of microcapsules that does not encapsulate the chromogenic substance - in other words, the microcapsule layer encapsulating the chromogenic substance. may be formed on a portion of the coating layer of microcapsules that do not contain a chromogen substance. In the above case, especially when forming both the microcapsule coating layer that does not contain a chromogen substance and the microcapsule layer that contains a chromogen substance by a spot printing method, there are the following difficulties. . That is, since capsule ink compositions contain microcapsules with larger particles than pigments added to ordinary dispersion ink compositions, when such capsule ink compositions are formed on a support by a printing method, printing The ink composition, particularly the capsule component, tends to accumulate at the edge portions of the plate, and when this accumulated ink composition is transferred to the support, areas with a large amount of ink will be created at the edges of the printing area. For this reason, if the capsule ink composition is formed twice in exactly the same size using a printing method, a portion with an extremely large amount of ink will be formed at the end of the printed area. and,
Transfer sheets having such areas with an abnormally large amount of ink are extremely susceptible to colored staining when handled overlapping with a receiving sheet. Therefore, if a high-quality transfer sheet with excellent color development properties and which does not easily cause color stains during handling is desired, a chromogen may be added to a portion of the coating layer of the microcapsules that do not contain a chromogen substance as described above. More preferred is a form in which a microcapsule layer containing body substances is formed. In addition, the transfer sheet produced by the method of the present invention not only has a form in which a microcapsule layer containing a chromogen substance is formed in one place on a coating layer of microcapsules that do not contain a chromogen substance; This also includes a form in which a microcapsule layer encapsulating a chromogen substance is formed at a plurality of positions on a coating layer of microcapsules that do not encapsulate a chromogen substance. The microcapsule layer containing a plurality of chromogen substances can be formed by selecting the chromogen substances to be encapsulated in the capsules for each ink composition so that each of them develops a different color tone. . Furthermore, in the present invention, it is preferable in terms of productivity and cost to form a coating layer of microcapsules that do not include a chromogen substance on the entire surface of the support by coating. Further, the manufacturing method of the present invention can be applied not only to upper sheets but also to sheets having a transfer layer such as inner sheets. (Examples) In order to further clarify the effects of the present invention, Examples and Comparative Examples are given below, but the present invention is not limited to these Examples. Parts and % in the examples represent parts by weight and % by weight, respectively, unless otherwise specified. Example 1 (Preparation of melamine-formaldehyde resin capsule ink containing color former) 8 parts of crystal violet lactone was mixed with 100 parts of alkyl diphenylethane (trade name Hysol).
SAS-296, manufactured by Nippon Petrochemicals Co., Ltd.) was heated and dissolved to obtain an internal phase oil. A 20% aqueous solution of caustic soda was added dropwise to 200 parts of a 3.0% aqueous solution of ethylene-maleic anhydride copolymer (trade name EMA31, manufactured by Monsanto) to adjust the pH.
After emulsifying this internal phase oil in a liquid with a temperature of 6.0, the system was heated to 55°C. Separately, 15 parts of melamine was added to 45 parts of a 37% formaldehyde aqueous solution and reacted at 60°C for 15 minutes to prepare a prepolymer aqueous solution. This prepolymer aqueous solution was added dropwise to the emulsion, and while stirring, 0.1N hydrochloric acid was added dropwise to adjust the pH.
After setting the temperature to 5.3, heat it to 80℃, and at that temperature
After holding for a period of time, the pH was lowered to 3.5 with 0.2N hydrochloric acid, and the mixture was further kept warm for 3 hours and then allowed to cool to obtain a capsule dispersion having an average particle size of 3.8 μm. This dispersion was then filtered, and after further washing with ethanol, the capsules were redispersed in a mixed solvent of 330 parts of ethanol and 165 parts of n-propanol.
To this was added 25 parts of light calcium carbonate and 80 parts of ethyl cellulose No. 14 (manufactured by Hercules) to obtain a flexo-type capsule ink. (Preparation of top paper) Ethylene-maleic anhydride copolymer (product name
3.0% aqueous solution of EMA−31 (manufactured by Monsanto) 200
After emulsifying 100 parts of alkyl diphenylethane (trade name: Hysol SAS-296, manufactured by Nippon Petrochemical Co., Ltd.) into a solution whose pH was set to 6.0 by adding 20% aqueous sodium hydroxide solution to the solution, the system was heated to 55°C. did. Separately, 15 parts of melamine was added to 45 parts of a 37% formaldehyde aqueous solution and reacted at 60°C for 15 minutes to prepare a prepolymer aqueous solution. This prepolymer aqueous solution was added dropwise to the emulsion, and while stirring, 0.1N hydrochloric acid was added dropwise to adjust the pH.
After setting the pH to 5.3, heat it to 80℃, hold it at that temperature for 1 hour, lower the pH to 3.5 with 0.2N hydrochloric acid, and then heat it to 80℃.
After being kept warm for an hour, it was allowed to cool to obtain a capsule dispersion with an average particle size of 7.0 μm. Thirty parts of starch particles were added to this dispersion, and the mixture was diluted to a concentration of 15% to obtain a casse cell coating liquid. The obtained capsule coating liquid was spread on a 40 g/m ² base paper using an air knife coater so that the solid content was 2.5 g/m ² . The above capsule ink was printed on the same side of the above coated paper at a speed of 80 m/min using a business form printing machine, and the ink amount was 3.0 g/ ^m2 .
A cm square spot print was obtained. (Creating the form below) 65 parts of light calcium carbonate, 20 parts of zinc oxide, 3.
15 parts of a blend of zinc 5-di(α-methylbenzene)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 (solid content) of carboxy-modified styrene-butadiene copolymer latex was added to a dispersion obtained by grinding 1 part in a ball mill for 24 hours.
The base paper was coated with an air knife coater so that the dry weight was 5 g/m ² on a base paper of 2 m ² . Example 2 (Preparation of acrylonitrile-based resin capsule ink containing color former) 65 parts of acrylonitrile, 6.5 parts of acrylamide, and 1 part of azobiscyanocyclohexane were mixed with the inner phase oil prepared in the same manner as in Example 1, and the inner phase oil was mixed with 1 part of azobiscyanocyclohexane. Obtained. This internal phase oil was emulsified in a mixture of 300 parts of water, 30 parts of salt, and 70 parts of colloidal silica (trade name Snotex 20, manufactured by Nissan Chemical Co., Ltd.), and kept at 95°C for 24 hours while stirring, then left to cool. The average particle size is 3.8μ
A capsule dispersion was obtained. Next, this dispersion was filtered, and after further washing with ethanol, the capsules were mixed with 330 parts of ethanol and n
- redispersed in a mixed medium of 165 parts of propanol;
To this was added 25 parts of light calcium carbonate and 80 parts of ethyl cellulose No. 14 (manufactured by Hercules) to obtain a flexo-type capsule ink. This capsule ink was spot printed in the same manner as in Example 1 to obtain a top paper. Comparative Example 1 A top paper was obtained by spot printing in the same manner as in Example 1 except that the capsule ink was directly printed on the 40 g/m ² base paper. Comparative Example 2 A top paper was obtained by spot printing in the same manner as in Example 2, except that the capsule ink was directly printed on the 40 g/m ² base paper. Example 3 (Preparation of urea-formaldehyde resin capsule ink containing color former) The internal phase liquid prepared in the same manner as in Example 1 was mixed with 5.0% of styrene-maleic anhydride copolymer (trade name: Scriptset 520, manufactured by Monsanto). % aqueous solution was added to 100 parts of the 20% aqueous solution of caustic soda, and the pH was adjusted to 4.0 to emulsify the solution. Next, add 20 parts of urea and 2 parts of resorcinol dissolved in 100 c.c. of water, and then
Fifty parts of a 37% formaldehyde aqueous solution was added, the temperature of the system was raised to 60°C, and the reaction was carried out for 5 hours to obtain a capsule dispersion having an average particle size of 3.9μ. Next, this dispersion was filtered and further washed with ethanol, and then the capsules were redispersed in a mixed solution of 330 parts of ethanol and 165 parts of n-propanol, and 25 parts of light calcium carbonate and 80 parts of ethyl cellulose were added thereto. A flexographic capsule ink was obtained. This capsule ink was spot printed in the same manner as in Example 1 to obtain a top paper. Example 4 (Preparation of urethane/urea membrane capsule ink containing color former) 30 parts of aromatic polyvalent isocyanate (trade name Coronate L, manufactured by Nippon Urethane Co., Ltd.) was dissolved in the inner phase oil prepared in the same manner as in Example 1. This oil was added to 200 parts of a 2% polyvinyl alcohol aqueous solution and emulsified, and the system was reacted at 80° C. for 4 hours to obtain a capsule dispersion having an average particle size of 3.9 μm. Next, this dispersion was filtered and further washed with ethanol, and then the capsules were redispersed in a mixed solvent of 330 parts of ethanol and 165 parts of n-propanol, and 25 parts of light calcium carbonate and 80 parts of ethyl cellulose were added thereto. A flexographic capsule ink was obtained. This capsule ink was spot printed in the same manner as in Example 1 to obtain a top paper. Comparative Example 3 A top paper was obtained by spot printing in the same manner as in Example 3 except that the capsule ink was directly printed on the 40 g/m ² base paper. Comparative Example 4 A top paper was obtained by spot printing in the same manner as in Example 4 except that the capsule ink was directly printed on the 40 g/m ² base paper. (Evaluation) The solvent resistance in the ink composition of the capsules used in the above examples and comparative examples and the color development of the pressure-sensitive copying paper obtained by printing are as shown in the table. be.

[Table] Example 5 (Preparation of melamine-formaldehyde resin capsule ink containing color former) In Example 1, 3-(N-ethyl-N-
A flexographic capsule ink was obtained in the same manner except that 10 parts of (isoamylamino)-6-methyl-7-phenylaminofluorane was used. (Preparation of top paper) Business form printing in which the capsule ink obtained above and the capsule ink containing crystal violet lactone prepared in the same manner as in Example 1 are placed on two rolls of flexographic printing plates, respectively. On the capsule coating layer that does not contain a chromogen substance and was formed in the same manner as in Example 1,
Printing was carried out at a speed of 80 m/min. to obtain a top paper having two 10 cm x 10 cm square spot printing areas with an ink amount of 3.0 g/m ² in each printing area. The obtained upper paper was layered on the lower paper prepared by the method described in Example 1, and the color was developed using a typewriter (HERMES 7 OOEL), resulting in 3-(N-ethyl-N-isoamylamino).
The area printed with the capsule ink containing -6-methyl-7-phenylaminofluorane is black, and the area printed with the capsule ink containing crystal violet lactone is blue, with a clear color density ( A recorded image having a color density determined by a Macbeth densitometer (black: 0.59, blue: 0.60) was obtained. Furthermore, even when the upper paper was overlapped with the lower paper and rubbed, almost no colored stains were generated. Example 6 (Preparation of capsule ink without chromogen substance) Ethylene-maleic anhydride copolymer (trade name
3.0% aqueous solution of EMA−31 (manufactured by Monsanto) 200
After emulsifying 100 parts of alkyl diphenylethane (trade name: Hysol SAS-296, manufactured by Nippon Petrochemicals) into a solution whose pH was adjusted to 6.0 by adding 20% caustic soda aqueous solution, the system was heated to 55°C. did. Separately, 15 parts of melamine was added to 45 parts of a 37% formaldehyde aqueous solution and reacted at 60°C for 15 minutes to prepare a prepolymer aqueous solution. This prepolymer aqueous solution was added dropwise to the emulsion, and while stirring, 0.1N hydrochloric acid was added dropwise to adjust the pH.
After setting the pH to 5.3, heat it to 80℃, hold it at that temperature for 1 hour, lower the pH to 3.5 with 0.2N hydrochloric acid, and then heat it to 80℃.
After being kept warm for an hour, it was allowed to cool to obtain a capsule dispersion with an average particle size of 4.0 μm. Next, this dispersion was filtered and further washed with ethanol, and then the capsules were redispersed in a mixed solvent of 330 parts of ethanol and 165 parts of n-propanol. A flexographic capsule ink was obtained by adding 80 parts (manufactured by Co., Ltd.). (Preparation of top paper) The capsule ink that does not contain a chromogen substance obtained above is printed at a speed of 80 m/min. on a 40 g/m ² base paper using a business form printing machine equipped with a flexo printing plate. , the ink amount is 2.5g/ ^m2
A spot print of 25 cm x 25 cm square was obtained. Next, 3- prepared in the same manner as in Example 5
A capsule ink composition containing (N-ethyl-N-isoamylamino)-6-methyl-7-phenylaminofluorane and a capsule ink composition containing crystal violet lactone prepared in the same manner as in Example 1. The objects were printed at a speed of 80 m/min. on the printing surface of the capsule ink that does not contain the chromogen substance using a business form printing machine that has flexo printing plates on two rolls, respectively. The amount of ink in the area is 3.0g/ ^m2 .
A top paper having two spot prints of 10 cm x 10 cm square was obtained. When the obtained upper paper was overlapped with the lower paper and printed using a typewriter in the same manner as in Example 5, the color density measured by the Macbeth densitometer was 0.56 (black colored area).
A clear colored image of 0.55 (blue colored area) was obtained.
Moreover, this upper paper hardly caused colored stains even when it was overlapped with the lower paper and rubbed. Example 7 (Preparation of upper paper) Capsule ink containing no chromogen material prepared in the same manner as in Example 6 was applied to two flexographic printing plates.
Business form printing machines on each roll of books print at a speed of 80 m/min. on base paper of 40 g/m ² , with an ink amount of 2.5 g/m ² each in 10 cm x 10 cm square spot printing. A print having two copies was obtained. Next, 3- prepared in the same manner as in Example 5
A capsule ink containing (N-ethyl-N-isoamylamino)-6-methyl-7-phenylaminofluorane and a capsule ink containing crystal violet lactone prepared in the same manner as in Example 1, Using a business form printing machine that has flexo printing plates on two rolls, the flexographic printing plates are placed so that they completely overlap each of the printing surfaces of the capsule ink that does not contain a chromogen substance in the two locations mentioned above.
Printing was carried out at a speed of 80 m/min. to obtain a top paper having two 10 cm x 10 cm square spot printing areas with an ink amount of 3.0 g/m ² in each printing area. When the obtained upper paper was overlapped with the lower paper and printed using a typewriter in the same manner as in Example 5, the color density measured by the Macbeth densitometer was 0.55 (black colored area).
A clear colored image of 0.56 (blue colored area) was obtained.
However, when this upper paper was overlapped with the lower paper and rubbed, the colored stains were quite noticeable. (Effects) The method of the present invention is characterized in that a sheet primed with oil-containing capsules is used as a support, whereby the core material in the inked capsule containing the chromogen material is removed. Absorption into the support is suppressed, and as a result, the capsule core material containing the chromogen material has good transferability to the opposing sheet, resulting in a pressure-sensitive copying paper with extremely high color development. Furthermore, when forming both the capsule layer that does not contain a chromogen substance and the capsule layer that contains a chromogen substance by printing, the capsule layer that contains a chromogen substance does not contain a chromogen substance. By forming it on a portion of the capsule layer, it is possible to obtain a pressure-sensitive copying paper of higher quality that is less likely to cause colored stains during handling and has good coloring properties.

Claims (1)

[Scope of Claims] 1. Production of pressure-sensitive copying paper characterized in that a microcapsule layer containing a chromogen substance is formed by printing on a coating layer of microcapsules containing no chromogen substance. Method. 2. The method for producing pressure-sensitive copying paper according to claim 1, wherein the wall of the microcapsule containing the chromogen substance is made of melamine-formaldehyde resin. 3. The method for producing pressure-sensitive copying paper according to claim 1, wherein the wall of the microcapsule containing the chromogen substance is made of an acrylonitrile resin. 4. The method for producing pressure-sensitive copying paper according to claim 1, wherein the average particle size of the microcapsules containing the chromogen substance is in the range of 1.0 to 5.0 μm. 5. Claim 1, wherein the microcapsule layer containing the chromogen substance is formed by printing on a part of the coating layer of the microcapsules that does not contain the chromogen substance.
A method for manufacturing the pressure-sensitive copying paper described.