JPS6242732A - Production of nonaqueous microcapsule composition - Google Patents

Abstract

PURPOSE:To enhance the resistance to solvents and strength of a capsule membrane by dispersing a microcapsule obtained by condensation-polymerize a hydrophilic aldehyde resin and an oil-soluble melamine-formaldehyde resin condensate in a nonaqueous medium. CONSTITUTION:A hydrophobic core substance incorporated with the initial condensate of an oil-soluble melamine-formaldehyde resin having 40-100% formaldehyde substitution degree, 80-100% alkylation degree and 4-16 hydrophobicity degree is emulsified in an aq. medium. Then a microcapsule obtained by condensation-polymerizing the hydrophilic aldehyde resin-forming material incorporated in the aq. medium and the initial condensate of an oil- soluble melamine-formaldehyde resin is dispersed in a non-aqueous medium to produce the titled microcapsule composition. The hydrophobicity degree of the initial condensate of the melamine-formaldehyde resin is preferably regulated to 5-8.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a microcapsule composition, and particularly to a method for producing a non-aqueous microcapsule composition.

``Prior art'' Microcapsules are suitable for stably retaining unstable substances (reactive substances, liquid substances, etc.), and are used in pharmaceuticals, agricultural chemicals, foods and beverages, fragrances, dyes, liquid crystals, temperature-indicating materials, It is applied to adhesives, fuel, etc. The most well-known use is pressure-sensitive copying paper, which has been used for more than 30 years.

Conventionally known methods for producing microcapsules include the coacervagedine method (for example, U.S. Pat. No. 2,800,457).
No. 2800458), interfacial polymerization method (e.g., Japanese Patent Publication No. 38-19574, Japanese Patent Publication No. 42
-446, Special Publication No. 42-771, Special Publication No. 49-45
133 etc.), 1n-situ polymerization method (
For example, Japanese Patent Publication No. 36-9168, Japanese Patent Publication No. 51-907
No. 9, Japanese Unexamined Patent Publication No. 53-84881, etc.) are known, and a large number of techniques have been developed.

Specifically, the microcapsules produced in this manner are coated on a support such as paper or film, or used as powder capsules.

Microcapsules containing fragrances, liquid crystals, electron-donating coloring agents, ligand compounds, etc. are usually produced in an aqueous medium, and are coated as is or with the addition of auxiliary agents, and then applied to a support such as paper. It is smeared using methods such as air knife coating, roll coach ink, and flake coating, or printed using methods such as silk screen, flexography, or gravure.

However, when applying or printing a microcapsule coating liquid dispersed in an aqueous medium using a coating machine or a printing machine, a large machine with a long drying zone is required to evaporate the aqueous medium, and a large number of machines are required. Requires energy. Further, when such a coating liquid is applied to paper, there is a problem that the paper as a support is likely to expand and contract, resulting in wrinkles.

The use of non-aqueous microcapsule compositions that use an organic medium instead of water is one way to solve the above problems. No. 49-32717, No. 56-115371, No. 56-144996,
Flexographic, gravure, or offset type inks are described in Japanese Patent Nos. 57-144788, 57-191088, and 58-191771. In addition, the special public
No. 8-12255, No. 57-53196, Japanese Unexamined Patent Publication No. 1973
-135720, 54-150212, 57-
Hot-melt inks are described in No. 117337, No. 58-141255, etc., and Japanese Patent Application Laid-Open No. 52-136
No. 016, No. 53-135718, etc. describe electron beam or ultraviolet curable inks. Of course, letterpress inks are also already known.

"Problems to be Solved by the Invention" These non-aqueous microcapsule compositions have any of the following drawbacks, and there is still room for improvement.

■ Because the solvent resistance of the capsule membrane is poor, the core material is extracted depending on the medium used.

■ Due to the strong hydrophilic nature of Kabuyal's surface, it cannot be sufficiently dispersed in hydrophobic media.

■ Due to the water-soluble polymer used as an emulsifier during capsule manufacturing, or because the capsule membrane itself has adhesive properties, capsules tend to stick to each other during spray drying, resulting in large capsules.

Therefore, a capsule coating liquid prepared by dispersing the powder capsules in a medium and coated on a support is extremely easily destroyed.

■ Because the mechanical strength of the capsule membrane is weak, those coated with the capsule coating liquid on a support are extremely susceptible to destruction.

■ Because the thermal strength of the capsule membrane is poor, part of the core substance flows out of the capsule during application.

■ When the capsule membrane is formed, a portion of the core material flows out of the capsule, and therefore only a capsule coating liquid containing the core material that is not encapsulated can be obtained.

"Means for Solving the Problems" The present inventors have conducted extensive research in view of the current situation, and have found that by using specific microcapsules, an extremely high-performance non-aqueous microcapsule composition that does not have any of the above-mentioned drawbacks has been developed. succeeded in getting something.

The present invention provides a hydrophobic core material containing an oil-soluble melamine-formaldehyde resin initial clamp having a degree of formaldehyde substitution of 40 to 100%, a degree of alkylation of 80 to 100%, and a degree of hydrophobicity of 4 to 16, in an aqueous medium. After emulsification, microcapsules obtained by polycondensing the hydrophilic aldehyde resin-forming material contained in the aqueous medium and the oil-soluble melamine-formaldehyde resin initial condensate are dispersed in a non-aqueous medium. This is a method for producing a characteristic non-aqueous microcapsule composition.

"Function" The oil-soluble melamine resin initial condensate used in the present invention must be completely or partially dissolved in the hydrophobic core material, and may be dissolved as appropriate within the above range depending on the HLB of the core material. Formaldehyde substitution degree, alkylation degree,
The degree of hydrophobicity is adjusted.

The degree of formaldehyde substitution is a value indicating what percentage of the active hydrogens possessed by the amino groups of melamine are substituted by methylol groups, alkoxymethylol groups, and methylene groups, and is expressed by the following formula.

Further, the degree of alkylation is a value indicating what percentage of the methylol group is alkoxylated, and is expressed by the following formula.

The degree of hydrophobicity is the total number of carbon atoms in all alkyl groups per melamine residue, and a melamine resin initial condensate with a degree of hydrophobicity of 4 to 16, more preferably 5 to 8, has a high core substance retention property. It is preferably used because it yields extremely good capsules, and among them, a melamine resin initial condensate containing hexamethoxyhexmethylol melamine as a main component is most preferably used.

In addition, in the present invention, the average number of nuclei represented by the average number of melamine residues contained in one molecule of the initial condensate is 1 to 1.
An initial fastener of 0, more preferably 1 to 5 is more preferably used.

In the present invention, when such an oil-soluble melamine-formaldehyde initial condensate is dissolved in a hydrophobic core material, when the initial fastener used has insufficient solubility or has a high viscosity, and when the initial fastener is dissolved in a hydrophobic core material, When the viscosity of the core substance is high, it is possible to heat the hydrophobic core substance or to use a polar solvent or a low boiling point solvent together.

Examples of low boiling point solvents used for this include n-pentane,
Methylene chloride, ethylene chloride, carbon disulfide, acetone, methyl acetate, chloroform, methyl alcohol, tetrahydrofuran, n-hexane, carbon tetrachloride, ethyl acetate, ethyl alcohol, n-propyl alcohol, 1so-7' alcohol, n -Butyl alcohol, t, s.

-butyl alcohol, t-butyl alcohol, n-pentyl alcohol, methyl ethyl ketone, benzene, toluene, xylene, ethyl ether and petroleum ether.

As the polar solvent, dioxane, cyclohexanone, methyl isobutyl ketone, dimethylformamide, etc. are used.

The amount of the oil-soluble melamine-formaldehyde initial condensate varies depending on the type and amount of the hydrophobic core material and hydrophilic aldehyde resin-forming material used, the particle size of the capsule, its intended use, etc. I can't decide, but the hydrophobic core substance is 100! It is preferably 0.1 part by weight or more and 20 parts by weight or less in terms of melamine based on the amount of It, particularly 0.
．． More preferably 1 part by weight or more and 5 parts by weight or less.

If the hydrophobic core material used is a solid, the first U1
If used, the solid is dispersed in a low boiling point solvent in which the metal or initial clamping material is dissolved, and then emulsified in water or a hydrophilic medium.

Examples of the hydrophilic aldehyde-based resin forming material used in the present invention include a combination of at least one member of amines or phenols and at least one member of aldehydes. Added in the form of fasteners.

Examples of the amines include urea, thiourea, alkylurea, ethyleneurea, acetoguanamine, benzoguanamine, melamine, guanidine, dicyandiamide, biuret, cyanamide, etc.; examples of the phenols include phenol, cresol, xylenol, resorcinol, hydroquinone, Examples of aldehydes such as pyrocatechol and pyrogallol include formaldehyde,
Examples include acetaldehyde, paraformaldehyde, hexamethylenetetramine, geltaraldehyde, glyoxal, and furfural.

In addition to the initial condensate of at least one compound belonging to amines or phenols as described above and at least one aldehyde, the initial condensate includes alkylated products such as methylated products, partially alkylated products, or anions thereof. , cationic or nonionic modified products are selected. In addition, these modifiers include:
For example, anionic modifiers such as sulfamic acid, sulfanilic acid, glycolic acid, glycine, acidic sulfite, phenol sulfonate, taurine, cationic modifiers such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dimethylaminoethanol, ethylene glycol, Examples include nonionic modifiers such as diethylene glycol.

As the hydrophilic aldehyde-based resin forming material, various materials can be used as mentioned above, but among them, a melamine-formaldehyde initial condensate or a methylated product thereof is preferable because a dense film can be obtained.

In addition, the blending amount of the hydrophilic aldehyde resin forming material is
It depends on the type of hydrophobic core material used, the intended use of the capsule, the amount of the oil-soluble melamine-formaldehyde initial condensate, etc. - although it cannot be determined generally.
Based on 400 parts by weight of the hydrophobic core substance, the amount is preferably 0.5 parts by weight or more and 40 parts by weight or less, particularly preferably 2 parts by weight or more and 20 parts by weight or less, in terms of amine compound or phenol compound.

In the present invention, the hydrophilic aldehyde resin-forming material can be added to the system before or during emulsification of the hydrophobic core substance, or at any stage after emulsification, but oil-soluble It is desirable to add the melamine-formaldehyde initial condensate after the polymerization has partially progressed.

In the present invention, as long as the hydrophobic core substance containing the oil-soluble melamine-formaldehyde initial condensate can be emulsified in water or a hydrophilic medium, it is not necessary to use an emulsifier, but an emulsifier may be used to facilitate emulsification. It is preferable to use such an emulsifier, and anionic, nonionic, cationic, or amphoteric polymer or low-molecular emulsifiers can be used.

As the anionic polymer, both natural and synthetic polymers can be used, such as -COO.

-8Os-, OPO”i, etc., specifically natural polymers such as gum arabic, carrageenan, sodium alginate, pectic acid, gum tragacanth, almond gum, and agar, carboxymethyl cellulose, sulfated cellulose, and sulfuric acid. Semi-synthetic polymers such as hydrogenated methyl cellulose, carboxymethyl starch, phosphorylated starch, lignin sulfonic acid, maleic anhydride (including hydrolyzed) copolymers, acrylic acid, methacrylic acid, or crotonic acid polymers. Polymers and copolymers, vinylbenzenesulfonic acid-based or 2-acrylamide-2-methyl-
Propanesulfonic acid-based polymers and copolymers, partial amides or partial esters of such polymers and copolymers, synthetic polymers such as carboxy-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol, phosphoric acid-modified polyvinyl alcohol, etc. can be mentioned.

More specifically, maleic anhydride-based (including hydrolyzed) copolymers include methyl vinyl ether-maleic anhydride copolymer, ethylene, maleic anhydride copolymer, and vinyl acetate-maleic anhydride copolymer. Examples include polymers, isobutylene-maleic anhydride copolymers, and styrene-maleic anhydride/maleic anhydride copolymers.

Examples of the acrylic acid copolymer, methacrylic acid copolymer, or crotonic acid copolymer include methyl acrylate-acrylic acid copolymer (hereinafter referred to as "copolymer"), ethyl acrylate-acrylic acid , methyl acrylate-methacrylic acid, methyl methacrylate-acrylic acid, methyl methacrylate-methacrylic acid, methyl acrylate-acrylamide-acrylic acid, acrylonitrile-acrylic acid,
Acrylonitrile-methacrylic acid, hydroxyethyl acrylate-acrylic acid, hydroxyethyl methacrylate-methacrylic acid, vinyl acetate-acrylic acid, vinyl acetate-methacrylic acid, acrylamide-acrylic acid, acrylamide-methacrylic acid, methacrylamide-acrylic acid, methacrylamide- Examples include copolymers such as methacrylic acid and vinyl acetate-crotonic acid.

Examples of vinylbenzenesulfonic acid copolymers or 2-acrylamido-2-methyl-propanesulfonic acid copolymers include methyl acrylate-vinylbenzenesulfonic acid (or salts thereof) copolymers, and vinyl acetate-vinylbenzenesulfonic acid copolymers. it combination, acrylamide-vinylbenzenesulfonic acid copolymer, acryloylmorpholine-vinylbenzenesulfonic acid copolymer, vinylpyrrolidone-vinylbenzenesulfonic acid copolymer, vinylpyrrolidone-2-
Examples include acrylamide-2-methyl-propanesulfonic acid copolymer.

As the nonionic polymer, both natural and synthetic polymers can be used, and examples thereof include those having an -OH group.

Specific nonionic semi-synthetic polymers include hydroxyethylcellulose, methylcellulose, pullulan (B
Examples include non-crystalline, easily water-soluble polymeric polysaccharides made from flour by microbial fermentation, soluble starches, and oxidized starches.

Further, as a synthetic product, polyvinyl alcohol can be mentioned.

Examples of cationic polymers include cation-modified polyvinyl alcohol, and examples of amphoteric polymers include gelatin.

Examples of low-molecular emulsifiers include anionic, cationic, nonionic, and amphoteric ones, but anionic ones are preferred, and among them, organic sulfuric acids having a total carbon number of 1 to 14 are preferred. Or L of organophosphoric acid
i”, Na”, K±N11. Ten salts are preferred, and specifically, sodium vinylsulfonate, sodium benzenesulfonate, sodium benzenesulfinate, p-
Sodium toluenesulfonate, sodium p-toluenesulfinate, sodium p-vinylbenzenesulfonate, sodium p-1-amylbenzenesulfonate,
Naphthalene-α-sodium sulfonate, Naphthalene-β
-Sodium sulfonate, 2-methylnaphthalene-6-sodium sulfonate, 2,6-dimethylnaphthalene-8
-sodium sulfonate, sodium 2゜6-dimethylnaphthalene-3-sulfonate, sodium 1-naphthol-4-sulfonate, sodium benzene-m-disulfonate, funnel oil, sodium diphenylphosphate, sodium phenylphosphonate, Examples include sodium di-n-butyl phosphate and sodium di-amyl phosphate.

In the present invention, the above-mentioned high-molecular or low-molecular emulsifiers may be used alone or in combination, but preferred are high-molecular emulsifiers, and among these, polymers or copolymers composed of anionic monomer units are preferred. , a copolymer of an anionic monomer unit and a hydrophobic heptamer unit is preferable, and a copolymer of acrylic acid and an acrylic ester, especially an acrylic acid-methyl acrylate copolymer, can easily stabilize emulsified particles. Therefore, it is preferably used.

It should be noted that the emulsifier as mentioned above can be used in water or a hydrophilic medium at a concentration of 0.0%.
The content is preferably 1% or more, and more preferably 1% or more from the viewpoint of ease of preparing the emulsion and stabilization of the emulsion. The upper limit of the amount used is determined by the viscosity of the system or the capsule preparation equipment, etc., but generally it is 20%.
It can be kept below.

In the present invention, so-called acid catalysts commonly used in the field of aminoaldehyde resin production, such as formic acid, acetic acid, citric acid, oxalic acid, valatoluenesulfonic acid, hydrochloric acid, and sulfuric acid, are used to maintain the reaction system acidic. .

The reaction conditions in the present invention vary depending on the type of initial condensate used and the intended use of the capsules, and are not generally determined, but are preferably at 40°C or higher for 1 hour or more, particularly preferably at 60°C or higher.
It is preferable to maintain it for at least 1 hour, especially for at least 3 hours, under conditions of 0°C or higher.In particular, when this is used as microcapsules for pressure-sensitive copying paper, the temperature is 70°C or higher or the pH is 6.0 or lower. , it is preferable to maintain the temperature at 60° C. or higher for 2 hours or more.

In the present invention, the hydrophobic core substance to be encapsulated in the microcapsules is not particularly limited, but the following substances are exemplified.

Animal oils such as fish oil, lard oil, etc., vegetable oils such as olive oil, peanut oil, linseed oil, soybean oil, castor oil, etc., mineral oils such as petroleum, kerosene, xylene, toluene, etc., alkyl-substituted diphenylalkanes, alkyl-substituted naphthalene, biphenylethane, methyl salicylate, diethyl adipate, di-n-propyl adipate,
Synthetic oils such as di-n-butyl adipate, di-methyl phthalate, diethyl phthalate, di-n-propyl phthalate, di-n-butyl phthalate, di-n-octyl phthalate, etc. A solution in which an electron-donating color former, an electron-accepting color developer, a ligand compound, an organic metal salt, etc. are dissolved in a water-insoluble or substantially water-insoluble liquid or the above-mentioned synthetic oil;
Water-insoluble metal oxides and salts, fibrous materials such as cellulose or asbestos, water-insoluble synthetic polymeric materials, minerals, pigments, glasses, fragrances, flavors, fungicidal compositions, Physiological compositions, fertilizer compositions,
Liquid crystals, temperature indicating materials, flame retardants, etc.

In the present invention, the aqueous microcapsule dispersion prepared as described above can be used as it is, or after passing through a concentration process such as filtration, through air drying, surface drying,
Fluidized drying, flash drying, spray drying, vacuum drying, freeze drying,
Most of the dispersion medium is removed by means such as infrared drying, high frequency drying, ultrasonic drying, pulverization drying, etc. to form powder capsules, which are then dispersed in a non-aqueous medium to form a non-aqueous microcapsule composition. prepared.

Among them, after drying the microcapsules, 3
Dispersion in a non-aqueous medium after treatment for 0 minutes or more is particularly preferable because it provides extremely excellent performance.

Alternatively, as described in JP-A No. 53-135718, it can be similarly prepared by mixing an aqueous capsule dispersion and a non-aqueous medium and then removing the aqueous medium under reduced pressure. Furthermore, it can also be prepared by filtering the capsule dispersion and then replacing it with a non-aqueous medium.

Although the microcapsules of the present invention are easily dispersed in non-aqueous media, a surfactant can be used to further improve the dispersibility. Examples of the surfactant include sodium alkyl sulfate, Sodium alkylbenzene sulfonate, sodium alkylnaphthalene sulfonate, sodium polystyrene sulfonate, sodium lignin sulfonate, sodium oleate amide sulfonate, sodium dialkyl sulfosuccinate, sulfated castor oil, dialkyl phosphate ester, alkyl phosphate ester, diaryl phosphorus Anionic activators such as acid esters and aryl phosphate esters; cationic activators such as halogenated trimethylaminoethyl alkylamide, alkylpyridinium sulfates, and halogenated alkyltrimethylammonium; polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester,
Nonionic surfactants such as polyoxynyretin alkylphenyl ether, polyhydric alcohol fatty acid ester, polyoxyethylene polyhydric alcohol fatty acid ester, sucrose fatty acid ester; amphoteric agents such as alkyltrimethylaminoacetic acid, alkyldiethylene 1-lyaminoacetic acid, lecithin, etc. Examples include activators and the like.

The non-aqueous medium used in the present invention may further include resins, capsule protectants, white pigments, desensitizing components (in the case of pressure-sensitive copying paper), ultraviolet absorbers, antioxidants, fluorescent dyes, plasticizers, etc., as required. Agents etc. can also be added.

Examples of resins include rosin (gum rosin, wood rosin, tall oil rosin), natural resins such as shellac, copal, dulman, giltonite, and zein, hardened rosin, ester gum and other rosin esters, maleic acid resin, and fumaric acid. resin, trimerized rosin, polymerized rosin,
Semi-synthetic resins such as rosin-modified phenolic resin MM, methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, ethylhydroxyethylcellulose, carboxymethylcellulose, cellulose acetate propionate, cellulose acetate butyrate, nitrocellulose, phenolic resins,
xylene resin, urea resin, melamine resin, ketone resin,
Coumarone/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 Polymer, styrene-maleic anhydride copolymer, methyl vinyl ether-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, polyvinyl alcohol,
Examples include synthetic resins such as 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 used, and the method disclosed in, for example, "Printing Ink Technology" CMC Co., Ltd. edition, etc. is suitable. Can be hired.

Specific examples of the capsule protectant include cellose powder, starch particles, microspheres, glass beads, and synthetic resin powder.

Examples of the desensitizing component include amino compounds known in the art in the case of leuco-based recording materials, and organic phosphorus-based compounds as described in Japanese Patent Application No. 149414-1983 in the case of iron and chelate-based recording materials. or a compound having an aminocarboxylic acid group.

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

As the non-aqueous medium used in the present invention, those known in the printing industry can be appropriately used, but specific examples include benzene, toluene, xylene, cyclohexane, Examples include hexane, ligroin, methyl isobutyl ketone, methyl acetate, ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-7' tanol, among others, methanol, ethanol, etc. A low boiling point alcohol is preferable, and in order to control drying of the composition, some n-propyl alcohol or isopropyl alcohol or water may be further added, or methyl acetate, ethyl acetate, 6141F phthyl, methyl cellosolve, ethyl cellosolve, etc. may be added. You can also do that.

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

Waxes can be used as a medium for hot-melt compositions, and these waxes include animal waxes such as beeswax, spermaceti wax, and lanolin, candelilla wax, carnauba wax, wood wax, rice wax, and sugarcane wax. vegetable waxes such as, mineral waxes such as montan wax, osikerite, lignite wax, etc.
Petroleum waxes such as paraffin wax and microcrystalline wax, modified waxes such as monk wax derivatives, paraffin wax derivatives, and microcrystalline wax derivatives, hydrogenated waxes such as castor wax and opal wax, low molecular weight polyethylene and its derivatives, and acra 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, myristic acid amide, stearic acid amide, behenic acid amide, ethylene bisstearic acid amide , fatty acid amide waxes such as caproleic acid amide, oleic acid amide, linoleic acid amide, ricinoleic acid amide, and linoleic acid amide, fatty acid based waxes such as stearic acid and behenic acid, alcoholic waxes such as stearyl alcohol, and distearyl phosphoric acid. Phosphate ester waxes such as esters may be used alone or in combination.

Among them, oxidized mineral wax such as montan wax, amide wax such as ethylene bisstearamide, stearamide, behenic acid amide, fatty acid wax, phosphate ester wax, and mixtures thereof, with needles of 0.1 to 30 Those having hardness, 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 described above, and in that case, aromatic hydrocarbon compounds that are dissolved in the molten aromatic hydrocarbon compound can be used. It is more preferable to use the obtained resin together. A good system can also be obtained by using an aromatic hydrocarbon compound and a wax in combination, but a more preferable system is when a resin is used in combination with the mixed system.

Specifically, the aromatic hydrocarbon compound is 2.6-
Diitubrobylnaphthalene, 1. 4. 5=trimethyl-naphthalene, 2,3.5-1-limethylnaphthalene, 2,3-dimethylnaphthalene, 1.3,6.8-tetramethylnaphthalene, 1°2-di-0-tolylethane, bis-(2 ,4,5-trimethylphenyl)methane,
1,18-diphenyl-octadecane, 1,3-terphenyl, 1.2-';-p-tolylethane, diphenyl-p-tolylmethane, 1,2-dibenzylbenzene, 3
．． 4-diphenylhexane, 1,2-bis(2゜3-dimethylphenyl)ethane, 4,4'-isopropylidenediphenol, bisresorcinol ethylene ether,
4-Tertiary Petit Roofenyl 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-3-octylcarbamoylnaphthalene, 4-hydroxybenzoic acid benzyl ester,
Examples include benzyl p-benzyloxybenzoate, 1,4-bispropionyloxybenzene, and 1,1-dibenzoylmethane.

In addition, examples of the resin include the resins mentioned above, among which cured rosin, ester gum, ethyl cellulose, phenol resin, rosin-modified phenol 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, representative compounds include polyethylene glycol diacrylate, brobylene 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,
Examples include butyl methacrylate and styrene. Regarding these monomers, please refer to JP-A-49-52889 and JP-A No. 48-52889.
No. 68641, No. 48-32586, Special Publication No. 49-7
You can also choose from those disclosed in No. 115 and the like.

When curing by ultraviolet rays, it is preferable to add a photopolymerization initiator to the medium.

Examples of the photopolymerization initiator include aromatic ketones, quinone compounds, ether compounds, and nitro compounds; specific examples include benzoquinone, phenanthrenequinone, naphthoquinone, diisopropylphenanthrenequinone, benzoin butyl ether, benzoin, and furoinbutyl ether. , Michler's ketone, Michler's thioketone, fluorenone, trinitrofluorenone, β-penzoylaminonafuculene, and the like.

Oil is used as a medium for the oxidative polymerization type (letterpress type) Mi product, and a solvent, wax, dryer, thickener, gelling agent, and thixotropy agent are added as necessary.

Examples of oils include vegetable oils (drying oils such as linseed oil and sunflower oil, semi-drying oils such as soybean oil, and non-drying oils such as castor oil), processed oils (dehydrated castor oil, polymerized oils, maleated oils). , 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.

The microcapsules used in the present invention have extremely excellent solvent resistance and exhibit particularly excellent properties as capsules for flexographic ink.

"Example" In order to more specifically explain the method of the present invention, examples will be described below regarding the case where the method is applied to the field of pressure copying, but of course the present invention is not limited thereto. Further, unless otherwise specified, parts and % in the examples represent parts by weight and % by weight, respectively.

Example 1 Preparation of microcapsules 5 parts of crystal bioleft lactone was mixed with 100 parts of alkylnaphthalene (trade name: KMC oil, manufactured by Kureno 1 Chemical Co., Ltd.)
30% of an initial condensate containing hexamethoxyhexmethylolmelamine as a main component (trade name: Cymel 350, manufactured by Mitsui Toatsu Chemical Co., Ltd.) was added to a solution obtained by heating and dissolving 30% of the solution at a temperature of 125°C.
An internal phase liquid was obtained by adding and mixing a portion.

Separately, polyacrylic acid (trade name Aron A-10H, manufactured by Toagosei Chemical Industry Co., Ltd.) was placed in a stirring mixing container equipped with a heating device.
200 parts of a 1.25% aqueous solution of was added thereto, and a 20% aqueous sodium hydroxide solution was added thereto to adjust the pH to 4.7 to prepare an aqueous medium for capsule production. After heating this aqueous medium to 80° C., the above-mentioned heated internal phase liquid was added therein with stirring, and emulsified and dispersed at 80° C. so that the average particle size was 6.0 μm.

In a stirring mixing vessel equipped with a heating device, 10 parts melamine and 3
30 parts of a 7% formaldehyde aqueous solution was added and stirred at 60° C. for 15 minutes to prepare a water-soluble melamine-formaldehyde initial condensate.

This liquid was added to the above emulsion after 40 minutes of emulsification dispersion, and the temperature of the system was maintained at 85"C for 1 hour, then raised to 95°C and maintained for 2 hours.

Next, 0.05N hydrochloric acid was gradually added to the system maintained at 95° C. over 5 hours while stirring to adjust the pH of the system to 3.6. Next, 100 parts of a 10% Cynol 350 aqueous solution was added and held at ~95°C for 1 hour to obtain a milky white capsule dispersion.

The resulting capsule dispersion was suction-filtered (7), and the paste was further dried at 120° C. for 1 hour to obtain powder capsules mainly consisting of mononuclear capsules.

Preparation of Capsule Ink 25 parts of the above powder capsules were dispersed in a mixed solution of 50 parts of ethyl alcohol and 21 parts of n-propyl alcohol.
A flexo-type capsule ink was obtained by adding and dissolving a portion.

65 parts of aluminum hydroxide, 20 parts of zinc oxide, 3.5-
Mixture of zinc di(α-methylbenzyl)salicylate and α-methylstyrene/styrene copolymer (melt ratio 80/
20) Add 20 parts (solid content) of carboxy-modified styrene-butadiene copolymer latex to a dispersion obtained by grinding 15 parts of polyvinyl alcohol aqueous solution (solid content) and 300 parts of water in a ball mill for 24 hours. In addition, a developer coating solution was prepared.

This coating liquid was applied to a 40 g/rd paper using an air knife coater so that the dry coating amount was 5 g/rd, and the above capsule ink was applied to the back side of the bottom paper with an ink amount of 3 g/rd.
An inner sheet was obtained by printing with a printing machine so as to have g/rK.

No colored stains were observed at all in the printed areas of the resulting inner paper. Further, when two sheets of inner paper were overlapped and printed using a typewriter, a clear colored image was obtained.

Comparative Example 1 Microcapsule Preparation 1 A solution obtained by heating and dissolving 5 parts of crystal violet lactone in 100 parts of KMC oil at a liquid temperature of 125°C,
60 parts of Cymel 350 were added and mixed to obtain an internal phase liquid.

Separately, in a stirred mixing vessel equipped with a heating device, add Aron A-1.
200 parts of a 1.25% 0H aqueous solution was added, and the pH was adjusted to 4.7 with a 20% aqueous sodium hydroxide solution to prepare an aqueous medium for capsule production.

After heating this aqueous medium to 80° C., the above-mentioned heated internal phase liquid was added thereto with stirring, and emulsified and dispersed at 80° C. so that the average particle size was 6.0 μm. System at 85℃
The temperature was raised to 95° C. and then held for 2 hours.

Next, 0.05N hydrochloric acid was gradually added to this system kept at 95°C under stirring over 5 hours to bring the pH of the system to 3.6.
Adjusted to. Then lO% Cynor 350 aqueous solution 10
0 part was added and kept at 95° C. for 1 hour to obtain a milky white capsule dispersion.

The resulting capsule dispersion was suction-filtered, and the paste was further dried to obtain powder capsules mainly consisting of mononuclear capsules.

Example 1 except that the powder capsule thus obtained was used.
An inner sheet was prepared in the same manner as above, but blue color stains had occurred in the developing layer of the printed portions of the resulting inner sheet.

Comparative Example 2 Preparation of Microcapsules 75 parts of crystal violin tract was mixed with 1 part of KMC oil.
00 parts by heating to obtain an internal phase liquid.

200 parts of a 1.25% aqueous solution of Aron A-10H was added to a stirring mixing vessel equipped with a heating device, and the pH was adjusted to 4.7 with a 20% aqueous sodium hydroxide solution to prepare an aqueous medium for capsule production. After heating this aqueous medium to 80° C., the above-mentioned heated internal phase liquid was added while stirring, and emulsified and dispersed at 80° C. so that the average particle size was 6.0 μm.

Separately, melamine 20
and 60 parts of 37% formaldehyde aqueous solution,
A water-soluble melamine-formaldehyde precondensate was prepared by grinding for 15 minutes at .degree. This liquid was added to the emulsion and held at 85°C for 1 hour, then heated to 95°C and held for 2 hours.

0.05 N hydrochloric acid was added to the system kept at 95°C while stirring.
The pH of the system was adjusted to 3.6 by gradual addition over time. Further, 100 parts of a 10% aqueous solution of Cynol 350 was added and held at 95° C. for 1 hour to obtain a milky white capsule dispersion.

The resulting capsule dispersion was suction filtered, and the paste was further dried to obtain patent capsules characterized by mononuclear capsules.

Preparation of capsule ink and creation of inner paper.

Example 1 except that the powder capsule thus obtained was used.
An inner sheet was prepared in the same manner as above, but pale blue stains had occurred in the developing layer of the printed portions of the resulting inner sheet.

Claims (6)

[Claims] (1) Emulsification of a hydrophobic core material containing an oil-soluble melamine-formaldehyde resin initial condensate with a degree of formaldehyde substitution of 40 to 100%, a degree of alkylation of 80 to 100%, and a degree of hydrophobicity of 4 to 16 in an aqueous medium. After that, microcapsules obtained by polycondensing the hydrophilic aldehyde resin forming material contained in the aqueous medium and the oil-soluble melamine-formaldehyde resin initial condensate are dispersed in a non-aqueous medium. A method for producing a non-aqueous microcapsule composition. (2) The production method according to claim (1), wherein the melamine-formaldehyde resin initial condensate has a degree of hydrophobicity of 5 to 8. (3) The production method according to claim (2), wherein the melamine-formaldehyde resin initial condensate is an initial condensate containing hexamethoxyhexamethylolmelamine as a main component. (4) The hydrophilic aldehyde resin forming material is melamine.
Claim No. 1 (which is a formaldehyde resin initial condensate)
The manufacturing method described in items 1) to (3). (5) The manufacturing method according to claim (1), wherein the non-aqueous medium is a flexographic ink medium. (6) After drying the microcapsules, heat at 100℃ or higher for 30 minutes.
The manufacturing method according to claim 1, wherein the method is dispersed in a non-aqueous medium after being treated for at least a minute.