JP2008073574A - Manufacturing method of fine particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing fine particles effectively from a dispersing element stabilized by an amphiphilic substance. <P>SOLUTION: The manufacturing method of the fine articles comprises the step of adding an enzyme decomposing the amphiphilic substance to the dispersing element in which fine particles stabilized by the amphiphilic substance are dispersed in a solvent, and of decomposing a part or the whole of the amphiphilic substance. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing fine particles from a dispersion containing an amphiphile.

  In the production of fine particles in the fields of ink, cosmetics, pharmaceuticals, etc., many methods are employed in which a dispersion stabilized with an amphiphile is prepared in a solvent and the desired fine particles are recovered from the dispersion. Yes. In the dispersion, the stronger the dispersion stabilizing action of the amphiphilic substance, the more the desired fine particles can be obtained by preventing aggregation and the like.

However, in order to recover the microparticles from the dispersion, generally a series of processes of concentration, purification and isolation must be performed. That is, the stronger the dispersion stabilizing action by the amphiphile, the more difficult it is to perform a series of processes of concentration, purification and isolation. Since it is difficult to efficiently produce fine particles with this, development of a more efficient production method is eagerly desired.
JP 7-216466 A Japanese Patent Laid-Open No. 11-71409

  Accordingly, a main object of the present invention is to provide a method for efficiently producing fine particles from a dispersion stabilized by an amphiphile.

  As a result of intensive studies to solve the problems of the prior art, the present inventor has found that the above object can be achieved by adopting a step of adding a specific substance to the dispersion, thereby completing the present invention. It came to do.

That is, the present invention relates to the following method for producing fine particles.
1. A part or all of the amphiphilic substance is decomposed by adding an enzyme that decomposes the amphiphilic substance to a dispersion in which fine particles stabilized by the amphiphilic substance are dispersed in a solvent. A process for producing fine particles, comprising the step of:
2. The dispersion is 1) a dispersion in which a thermochromic composition containing a color former (electron-donating color-forming organic compound), a developer (electron-accepting compound) and a desensitizer is dispersed in a solvent or 2) The production method according to item 1, wherein the microcapsules containing the composition are dispersed in a solvent.
3. Item 3. The production method according to Item 1 or 2, wherein the solvent is water or an aqueous solvent.
4). Item 4. The production method according to any one of Items 1 to 3, wherein the amphiphilic substance is at least one of a polysaccharide and a protein.
5. Item 5. The production method according to any one of Items 1 to 4, further comprising a step of removing part or all of the solvent.
6). A part or all of the amphiphilic substance is decomposed by adding an enzyme that decomposes the amphiphilic substance to a dispersion in which fine particles stabilized by the amphiphilic substance are dispersed in a solvent. A method for purifying fine particles, comprising the step of:
7). A part or all of the amphiphilic substance is decomposed by adding an enzyme that decomposes the amphiphilic substance to a dispersion in which fine particles stabilized by the amphiphilic substance are dispersed in a solvent. A method for collecting fine particles, comprising the step of:

  According to the production method of the present invention, an enzyme capable of decomposing the amphiphilic substance is used in a dispersion in which fine particles stabilized by the amphiphilic substance are dispersed in a solvent. Can be done. That is, the present invention can realize efficient production of fine particles by introducing a combination of a specific amphiphile and an enzyme.

  The production method of the present invention can be suitably used in various fine particle production fields including inks, foods, pharmaceuticals, cosmetics and the like.

  In the method for producing fine particles of the present invention, the amphiphile is added by adding an enzyme that decomposes the amphiphilic substance to a dispersion in which fine particles stabilized by the amphiphilic substance are dispersed in a solvent. It includes a step of decomposing part or all of the sexual substance.

The fine particles may be either inorganic (including metal) or organic fine particles. Moreover, any of solid fine particles, liquid fine particles, or a mixture thereof may be used.

  The use may be any of dyes or pigments, pharmaceuticals, foods, cosmetics, other chemicals, and the like.

  The average particle size of the fine particles is not particularly limited, but can be appropriately set within a range of 0.01 to 100 μm (preferably 0.1 to 10 μm).

The form of the dispersion is not particularly limited, and may be any form such as a suspension or an emulsion.

  The method for preparing the dispersion is not limited, and a dispersion prepared by a known method can be used. For example, 1) an organic compound particle dispersion (emulsion) prepared by an emulsification method in the presence of an amphiphile, and 2) a polymer prepared by emulsion polymerization or suspension polymerization in the presence of an amphiphile. Particle dispersion, 3) inorganic compound particle dispersion prepared in the presence of an amphiphilic substance (protective colloid), 4) polymer wall microcapsule dispersion prepared in the presence of an amphiphilic substance (protective colloid), 5) Crystalline particle dispersions precipitated in the presence of an amphiphilic substance (protective colloid).

  Any known solvent can be used as the dispersion medium. In the present invention, water or an aqueous solvent is particularly preferable. Examples of the aqueous solvent include a mixed solution (mixed solution) of water and a water-soluble organic solvent (ethanol or the like).

  The use of the dispersion is not limited, but an ink dispersion can be particularly preferably used. For example, JP-A-60-99695, JP-A-60-152586, JP-A-61-223583, JP-A-61-2261389, JP-A-61-1980, JP-A-6-65568, etc. As disclosed, an emulsion obtained by emulsifying a thermochromic composition with a homomixer or the like can also be applied as the dispersion. In addition, the microcapsules disclosed in JP-A-6-65568 can be applied as the dispersion. Specifically, 1) An emulsion in which a thermochromic composition containing a color former (electron-donating color-forming organic compound), a developer (electron-accepting compound) and a desensitizer is dispersed in a solvent. Or 2) A slurry in which microcapsules encapsulating the composition are dispersed in a solvent (hereinafter, both are also referred to as “ink dispersion”) can be suitably used as the dispersion. A well-known thing can also be used for these ink dispersions.

  As the amphiphilic substance, known substances can be used. For example, at least one of protein, polysaccharide and surfactant can be used. 1) As proteins (including modified products thereof), for example, gelatin, phthalated gelatin, gluten, albumin, hydrolyzed collagen, casein, etc. 2) As polysaccharides (including modified products thereof), for example, gum arabic, dextrin, alginic acid , Phosphorylated starch, carboxymethyl cellulose, 3) surfactants (cationic surfactants, anionic surfactants, nonionic surfactants, amphoteric surfactants), for example, polyoxyethylene fatty acid esters, sorbitan esters And ester surfactants such as polyoxyethylene-added sorbitan ester, polyoxyethylene-added sorbitan ester, glycerin monofatty acid ester, polyglycerin monofatty acid ester, and sucrose fatty acid ester. The surfactant preferably excludes nonionic surfactants.

  These amphiphiles can be used alone or in combination of two or more depending on the type of the dispersion. For example, when the ink dispersion is used as a dispersion, at least one of polysaccharides and proteins can be preferably used, and at least one of gelatin and gum arabic is particularly preferable.

  The amphiphilic substance can be used in the form as it is, but may be used in the form of an aqueous solution or the like.

  Although the usage-amount of an amphiphilic substance can be suitably set according to the kind etc. of amphiphilic substance to be used, normally it can use suitably within the range of 1 to 30 weight% in a solvent.

Addition of enzyme In the present invention, by adding an enzyme that decomposes an amphiphilic substance, a part or all of the amphiphilic substance is decomposed.

  As the enzyme, an enzyme that decomposes the amphiphile is used. That is, an enzyme (enzyme preparation) that catalyzes a decomposition reaction by a hydrolysis reaction or an oxidation-reduction reaction using the amphiphilic substance exemplified above as a substrate can be used. Accordingly, the type of enzyme used can be appropriately selected from known or commercially available types according to the type of amphiphile used. For example, 1) protease (proteolytic enzyme), peptide degrading enzyme (peptidase), etc. if the amphiphile used is a protein, 2) cellulase (cellulose degrading enzyme), if the amphiphile used is a polysaccharide , Starch-degrading enzyme (amylase), dextrin-degrading enzyme (dextranase), glucose-degrading enzyme (glucosidase), etc. 3) If the amphiphile used is an ester surfactant, esterase (ester-degrading enzyme), etc. 4) An oxidoreductase (dehydrogenase, reductase, oxidase, etc.) can be used if the amphiphile to be used is a surfactant that decomposes by a redox reaction.

  The amount of enzyme added depends on the type and amount of amphiphile used, but is usually 0.001 to 10 parts by weight, especially 0.01 to 1% by weight, based on 1 part by weight of the amphiphile. Is preferred. By setting within this range, the degradation of the amphiphile by the enzyme can be effectively advanced.

  In addition, a known additive can be added to the dispersion as long as the action of the enzyme is not hindered. For example, a pH adjuster, a flocculant, an inorganic salt, a dry aggregation inhibitor, and the like can be added. These are preferably 0.02 to 200 parts by weight, particularly 0.2 to 20 parts by weight, based on 1 part by weight of the amphiphilic substance. If set within this range, particularly when the ink dispersion is used as a dispersion, bleed that may occur when blended with a medium or a molding resin, or agglomeration of microcapsules during drying is prevented more effectively. be able to.

  The decomposition reaction conditions vary depending on the type of dispersion used, the type and amount of enzyme used, and the like. The reaction temperature is generally about 0 to 100 ° C, preferably 30 to 50 ° C. The reaction time may be several minutes to several hours, preferably 1 to 48 hours. The decomposition of the amphiphile by the addition of the enzyme can be confirmed by observing the viscosity of the dispersion, the sedimentation state of the particles, and the like.

  In the present invention, prior to the addition of the enzyme, the dispersion may be diluted to promote washing (replacement of the liquid). What is necessary is just to set a dilution degree suitably according to the kind etc. of dispersion liquid.

  Further, the pH of the dispersion can be adjusted in advance prior to the addition of the enzyme. For example, when an enzyme having an optimum pH of 7.0 is used, it is desirable to adjust the pH to a range of 5.0 to 9.0. Such pH adjustment increases the efficiency of the enzyme reaction. The pH adjustment may be performed using a known pH adjuster such as hydrochloric acid, sulfuric acid, or sodium hydroxide.

  After the addition of the enzyme, a nonionic surfactant can be added as a dry aggregation inhibitor as necessary. Aggregation of particles during drying can be prevented by adding a nonionic surfactant. As the nonionic surfactant, a known or commercially available one can be used. For example, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene hydrogenated castor oil, ether type such as polyoxyethylene alkyl thioether, polyoxyethylene mono fatty acid ester, polyoxyethylene difatty acid ester, polyoxyethylene propylene glycol Examples include fatty acid esters, propylene glycol fatty acid esters, polyoxyethylene sorbitan monofatty acid esters, glycerol monofatty acid esters, ester types such as sucrose fatty acid esters, and alkanolamide types such as polyoxyethylene alkylamides.

  The addition amount of the nonionic surfactant is usually 0.02 to 200 parts by weight, particularly preferably 0.2 to 20 parts by weight with respect to 1 part by weight of the amphiphilic substance.

In the present invention such as recovery of fine particles, the step after decomposing the amphiphile by adding an enzyme is not particularly limited. For example, all of the solvent can be removed and recovered as a powder by a solid-liquid separation method such as centrifugation, filtration, decantation, or distillation. Moreover, it is good also as a concentrate by removing a part of solvent by these methods. Any of these solid-liquid separation methods can be carried out according to a known method. Prior to performing these solid-liquid separation methods, a flocculant can be added in advance.

<Embodiment>
Hereinafter, as a specific example of an embodiment of the present invention, there is provided a thermochromic composition comprising 1) a color former (electron-donating color-forming organic compound), a developer (electron-accepting compound) and a desensitizer. A case where a dispersion obtained by dispersing in a solvent or 2) a dispersion obtained by dispersing microcapsules encapsulating the composition in a solvent will be described.
1-1. Thermochromic composition
Electron-donating color- forming organic compound The electron-donating color-forming organic compound (color-developing agent) is not limited as long as it reacts with the electron-accepting compound (developer) and develops color. Can be used. For example, the following compounds can be preferably used. These can be used alone or in combination of two or more.

(1) Fluoranes ... 2 '-[(2-chlorophenyl) amino] -6'-(dibutylamino) -spiro [isobenzofuran-1 (3H), 9 '-(9H) xanthen] -3-one, 3 -Diethylamino-6-methyl-7-chlorofluorane, 3-dimethylaminobenzo (a) -fluorane, 3-amino-5-methylfluorane, 2-methyl-3-amino-6,7-dimethylfluorane, 2-Bromo-6-cyclohexylaminofluorane, 6 '-(ethyl (4-methylphenyl) amino-2'-(N-methylphenylamino) -spiro (isobenzofuran 1 (3H), 9 '-(9H) Xanthene) -3-one and the like;
(2) Fluorenes ... 3,6-bis (diethylamino) fluorene spiro (9.3 ')-4'-azaphthalide, 3,6-bis (diethylamino) fluorene spiro (9.3')-4 ', 7' -Diazaphthalide etc .;
(3) Diphenylmethanephthalides: 3,3-bis- (p-ethoxy-4-dimethylaminophenyl) phthalide and the like;
(4) Diphenylmethane azaphthalides: 3,3-bis- (1-ethoxy-4-diethylaminophenyl) -4-azaphthalide and the like;
(5) Indolylphthalides: 3,3-bis (n-butyl-2-methylindol-3-yl) phthalide, 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide etc;
(6) Phenylindolylphthalides: 3- (1-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) phthalide and the like;
(7) Phenylindolylazaphthalides: 3- (2-Ethoxy-4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide, 3- [2- Ethoxy-4- (N-ethylanilino) phenyl] -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide and the like;
(8) Styrylquinolines: 2- (3-methoxy-4-dodecoxystyryl) quinoline and the like;
(9) Pyridines: 2,6-diphenyl-4- (6-dimethylaminophenyl) pyridine, 2,6-diethoxy-4- (4-diethylaminophenyl) pyridine and the like;
(10) Quinazolines: 2- (4-N-methylanilinophenyl) -1-phenoxyquinazoline, 2- (4-dimethylaminophenyl) -4- (1-methoxyphenyloxy) quinazoline and the like;
(11) Biskinazolines: 4,4 ′-(ethylenedioxy) -bis [2- (1-diethylaminophenyl) quinazoline], 4,4 ′-(ethylenedioxy) -bis [2- (1-di -N-butylaminophenyl) quinazoline] and the like;
(12) Ethylene phthalides: 3,3-bis [1,1-bis- (p-dimethylaminophenyl) ethyleno-3] phthalide and the like;
(13) Ethylenoazaphthalides: 3,3-bis [1,1-bis- (p-dimethylaminophenyl) ethyleno-2] -4-azaphthalide, 3,3-bis [1,1-bis- (P-dimethylaminophenyl) ethyleno-2] -4,7-diazaphthalide and the like;
(14) Triphenylmethanephthalides: crystal violet lactone, malachite green lactone, etc .;
(15) Polyaryl carbinols: Michler hydrol, crystal violet carbinol, malachite green carbinol, etc .;
(16) Leucooramines: N- (2,3-dichlorophenynyl) leucooramine, N-benzoyloramine, N-acetylauramine and the like;
(17) Rhodamine lactams: rhodamine β-lactams;
(18) Indolines: 2- (phenyliminoethylidene) -3,3-dimethylindoline and the like;
(19) Spiropyrans: N-3,3-trimethylindolinobenzospiropyran, 8-methoxy-N-3,3-trimethylindolinobenzospiropyran, etc .;
In addition to these, diazarhodamine lactones, xanthenes and the like can also be used in the present invention.

  In the present invention, at least one of fluorans among these electron donating color-forming organic compounds can be suitably used. In particular, 2 '-[(2-chlorophenyl) amino] -6'-(dibutylamino) -spiro [isobenzofuran-1 (3H), 9 '-(9H) xanthen] -3-one is more preferable.

  The content of the electron-donating color-forming organic compound can be appropriately set according to the type of the compound, but generally it is about 0.1 to 50% by weight, particularly 0 in the thermochromic composition of the present invention. It is desirable to be 8 to 15% by weight. When the content is less than 0.1% by weight, the color density may be lowered. Moreover, when the said content exceeds 50 weight%, there exists a possibility that background coloring may become large.

Electron-accepting compound The electron-accepting compound is not limited, and known or commercially available compounds can be used as appropriate. For example, the following compounds can be preferably used. These can be used alone or in combination of two or more.

(1) Phenols: bisphenol A or derivatives thereof, bisphenol S or derivatives thereof, p-phenylphenol, dodecylphenol, o-bromophenol, ethyl p-oxybenzoate, methyl gallate, phenol resin, etc. (2) Phenols Metal salts of phenols: Metal salts of phenols such as Na, K, Li, Ca, Zn, Al, Mg, Ni, Co, Sn, Cu, Fe, Ti, Pb, Mo, etc. (3) Aromatic carboxylic acids and carbon Aliphatic carboxylic acids of formula 2-5: phthalic acid, benzoic acid, acetic acid, propionic acid, etc. (4) Metal salts of carboxylic acids: sodium oleate, zinc salicylate, nickel benzoate, etc. (5) Acidic phosphate esters ... Butyl acid phosphate, 2-ethylhexyl-acid phosphate, dodecyl acid phosphate (6) Metal salts of acidic phosphate esters: Metal salts of acidic phosphate esters such as Na, K, Li, Ca, Zn, Al, Mg, Ni, Co, Sn, Fe, Ti, Pb, and Mo (6) Triazole compounds: 1,2,3-triazole, 1,2,3-benzotriazole, etc. (7) Thiourea and its derivatives ... diphenylthiourea, di-o-toluylurea, etc. (8) Halohydrins ... 2 , 2,2-trichloroethanol, 1,1,1-tribromo-2-methyl-2-propanol, N-3-pyridyl-N ′-(1-hydroxy-2,2,2-trichloroethyl) urea, etc. 9) Benzothiazoles: 2-mercaptobenzenethiazole, 2- (4′-morpholinodithio) benzothiazole, N-tert-butyl-2-benzothiazolylsulfenamide, 2-mer The Zn salts present invention script benzothiazole, it may be used at least one suitably phenols and their metal salts of these electron-accepting compound. In particular, at least one selected from 1) bisphenol A and derivatives thereof and 2) bisphenol S and derivatives thereof is more preferable, and 2,2-bis (4′-hydroxyphenyl) propane is most preferable.

  The content of the electron-accepting compound can be appropriately set according to the type of the compound, but generally it is about 0.05 to 98% by weight, particularly 0.5 to 77% in the thermochromic composition of the present invention. It is desirable to set the weight%. When the content is less than 0.05% by weight, the color density may be lowered. Moreover, when the said content exceeds 98 weight%, there exists a possibility that background coloring may become large.

  In the present invention, in relation to the electron donating colorable organic compound, 0.1 to 100 parts by weight, particularly 0.5 to 100 parts by weight of the electron accepting compound with respect to 1 part by weight of the electron donating colorable organic compound. 20 parts by weight is preferable.

As the desensitizer , a known or commercially available one can be used. Specifically, the desensitizer shown below can be illustrated.

(1) Alcohols: n-cetyl alcohol, n-octyl alcohol, cyclohexyl alcohol, hexylene glycol, etc. (2) Esters: myristic acid ester, lauric acid ester, dioctyl phthalate, stearyl laurate, stearyl palmitate, etc. 3) Ketones: methyl hexyl ketone, benzophenone, stearone, etc. (4) Ethers: butyl ether, diphenyl ether, distearyl ether, etc. (5) Acid amide compounds: oleic acid amide, stearic acid amide, lauric acid amide, lauric acid N -Octylamide, caproic acid anilide, etc. (6) Fatty acids having 6 or more carbon atoms ... Lauric acid, stearic acid, 2-oxymyristic acid, etc. (7) Aromatic compounds ... Diphenylmethane, dibenzyltoluene, propyldiphe (8) Thiols: n-decyl mercaptan, n-myristyl mercaptan, n-stearyl mercaptan, isocetyl mercaptan, dodecyl benzil mercaptan (9) Sulfides: Di-n-octyl sulfide, di-n-decyl sulfide, diphenyl sulfide, diethylphenyl sulfide, dilauryl dithiopropionate, etc. (10) Disulfides: di-n-octyl disulfide, di- n-decyl disulfide, diphenyl disulfide, dinaphthyl disulfide, etc. (11) Sulfoxides: diethyl sulfoxide, tetramethylene carboxyoxide, diphenyl sulfoxide, etc. (12) Sulfones: diethyl sulfo (13) Azomethines: benzylidene lauryl amine, p-methoxybenzylidene lauryl amine, benzylidene p-anisidine, etc. (14) Fatty acid primary amines: stearylamine oleate, myristyl stearate Among these, esters are preferable, and at least one of stearyl laurate and stearyl valmitate is more preferable.

  The content (total amount) of the desensitizer can be appropriately set according to the type of the compound and the like, but is generally about 1 to 99% by weight, particularly 19 to 99% by weight in the thermochromic composition of the present invention. % Is desirable. If the content is less than 1% by weight, the background color may increase. On the other hand, when the content exceeds 99% by weight, the color density may be lowered.

Other components In the thermochromic composition of the present invention, if necessary, an ultraviolet absorber, an infrared absorber, an antioxidant, a non-thermochromic pigment, a non-thermochromic dye, a fluorescent whitening agent, a surfactant. Further, known additives such as an antifoaming agent, a leveling agent, a solvent, and a thickener may be added to the composition.

Method for producing thermochromic composition The thermochromic composition can be prepared by putting these components into a known mixer such as a stirrer, mixer, homogenizer, and the like and mixing them uniformly. In this case, it is preferable to mix while heating. The heating temperature is not limited, but is usually about 120 to 180 ° C.
1-2. Microcapsule The present invention can also be applied to a thermochromic microcapsule obtained by encapsulating the thermochromic composition in a microcapsule. This microcapsule can adopt the same structure as a known microcapsule except that the thermochromic composition of the present invention is used as the content. For example, the microcapsule which encloses the content containing a thermochromic composition with a wall film is mentioned.

  In addition to the thermochromic composition, the contents may include a solvent (dissolution aid), an emulsifier, and the like as necessary.

  The content of the thermochromic composition is not limited, but generally it is preferably about 6 to 98% by weight, particularly 75 to 95% by weight when the microcapsule is 100% by weight.

  The solvent can be appropriately selected from known solvents as long as the thermochromic composition and the wall film material can be uniformly dissolved and the thermochromic performance is not impaired. In particular, those that can be removed in a later step are desirable. For example, ester solvents (excluding the compounds of (1) and (2) above), ketone solvents, ether solvents, glycol ether solvents, hydrocarbon solvents, aromatic solvents, nitrogen-containing solvents, Silicon solvents, halogen-containing solvents, etc. can be used. These can be used alone or in combination of two or more.

  As the emulsifier, an amphiphilic substance that is adsorbed and stabilized on the surface of the oil droplet when the content is emulsified in water is used. These can be employed from known emulsifiers. For example, water-soluble natural polymers, water-soluble synthetic polymers, surfactants, inorganic fine particles and the like can be mentioned. These can be used alone or in combination of two or more. The emulsifier can be appropriately determined according to the type of the resin component constituting the wall film. For example, when the resin component is an epoxy resin, casein or the like can be suitably used as the emulsifier, in addition to polysaccharides such as gum arabic and gelatin. For example, when a melamine formalin resin is used as a resin component, an ethylene maleic anhydride copolymer or the like can be suitably used as an emulsifier. Furthermore, when urethane (isocyanate) is used as the resin component, gelatin, polyvinyl alcohol, or the like can be used.

  In general, a resin-based wall film can be suitably used as the wall film. As the resin, for example, various thermoplastic resins and thermosetting resins can be used. More specifically, epoxy resin, polyamide resin, acrylonitrile resin, polyurethane resin, polyurea resin, urea-formaldehyde resin, melamine-formaldehyde resin, benzoguanamine resin, butylated melamine resin, butylated urea resin, urea-melamine system Examples thereof include resins. These resin components can be used alone or in combination of two or more. When manufacturing microcapsules, these raw materials are used, and these can be polymerized suitably by polymerizing them.

Method for Producing Microcapsules The method for producing microcapsules (thermochromic microcapsules) can be carried out according to known microencapsulation except that the thermochromic composition of the present invention is used as the contents. Examples of the microencapsulation method include an interfacial polymerization method (polycondensation and addition polymerization), an in situ polymerization method, a coacervation method, a submerged drying method, and a spray drying method.

  As an example of a method for producing microcapsules, for example, 1) In the presence or absence of a solvent, a main raw material (excluding a crosslinking agent) that can constitute a wall film is mixed or dissolved with a thermochromic composition. The first step of preparing the solution by the above, 2) adding the obtained solution to the aqueous emulsifier solution, the second step of preparing the O / W emulsion, 3) adding the cross-linking agent or its solution to the O / W emulsion By the method including the third step, microcapsules can be preferably produced.

First Step In the first step, in the presence or absence of a solvent, a solution is prepared by mixing or dissolving a main raw material (excluding a crosslinking agent) that can constitute a wall film with a thermochromic composition. .

  As the thermochromic composition, those described above are used. The amount used is usually 5 to 50 parts by weight, particularly 10 to 40 parts by weight, based on 100 parts by weight of the emulsifier aqueous solution. When the amount used is less than 5 parts by weight, productivity may be reduced. Moreover, when the said usage-amount exceeds 50 weight part, there exists a possibility that emulsification may become difficult.

  What is necessary is just to use what becomes a component which comprises the wall film demonstrated by said (3) as said main raw material and a crosslinking agent. In this case, it is more desirable to set appropriately according to the microencapsulation method. For example, in the case of microencapsulation by an in situ polymerization method, when the wall film is made of melamine resin, polyurea resin or the like, melamine, urea or the like may be used as the main raw material and formalin may be used as the crosslinking agent. In the case of microencapsulation by an in situ polymerization method, when the wall film is a urethane resin or the like, an isocyanate compound may be used as a main raw material and a polyalcohol may be used as a crosslinking agent. For example, in the case of microencapsulation by the interfacial polymerization method (polycondensation), when the wall film is an epoxy resin or the like, an epoxy compound may be used as a main raw material and a polyamine compound may be used as a crosslinking agent. In the case of microencapsulation by the interfacial polymerization method (polycondensation), when the wall film is a urethane resin or the like, an isocyanate compound may be used as a main raw material and a polyamine compound may be used as a crosslinking agent. In the case of microencapsulation by the interfacial polymerization method (polycondensation), when the wall film is a polyamide resin or the like, an acid chloride compound may be used as a main raw material and a polyamine compound may be used as a crosslinking agent. In the case of microencapsulation by the interfacial polymerization method (addition polymerization), when the wall film is an acrylic resin or the like, an acrylic compound may be used as a main raw material and a peroxy compound may be used as a crosslinking agent.

  The amount of the main raw material and the crosslinking agent used is not particularly limited. The main raw material can be appropriately set in the range of usually 1 to 50 parts by weight, preferably 2 to 10 parts by weight with respect to 100 parts by weight of the emulsifier aqueous solution. The crosslinking agent can be appropriately set within the range of usually 0.5 to 25 parts by weight, preferably 1 to 5 parts by weight with respect to 100 parts by weight of the emulsifier aqueous solution. When the amount of the main raw material or the crosslinking agent used is too small or too large, the reaction becomes insufficient, and the strength, heat resistance, etc. of the capsule (wall film) may be lowered.

  In the first step, a solvent can be used as necessary. As the solvent, those listed above can be used.

  Although the usage-amount of a solvent is not limited, Usually, it can set suitably in the range of 0-100 weight part with respect to 100 weight part of emulsifier aqueous solution, Preferably it is in the range of 0-40 weight part.

Second Step In the second step, the obtained solution is added to an aqueous emulsifier solution to prepare an O / W emulsion.

  As the emulsifier aqueous solution, an aqueous solution obtained by dissolving the above emulsifier in water can be used. The concentration of the aqueous emulsifier solution can be appropriately set according to the type of the emulsifier and the like, but is generally 0.1 to 15% by weight, particularly preferably 0.5 to 8% by weight. If the concentration is less than 0.2% by weight, emulsification may be difficult. If the concentration exceeds 15% by weight, foaming may occur.

  In the present invention, the O / W emulsion can be prepared according to a known method such as a stirring method or a membrane permeation method. In this case, the droplet diameter of the O / W emulsion may be about 0.1 to 20 μm.

Third Step In the third step, a crosslinking agent or a solution thereof is added to the O / W emulsion. As a crosslinking agent, each crosslinking agent enumerated above can be used. As the solution of the crosslinking agent, for example, an aqueous crosslinking agent solution obtained by dissolving the crosslinking agent in water can be suitably used. The concentration of the aqueous solution in this case is not limited, but usually it may be appropriately set within a range of about 1 to 100% by weight. The method for adding the cross-linking agent is not particularly limited, but it is preferable to add it by dropping.

After the addition of the cross-linking agent or the solution thereof, the cross-linking proceeds and if the cross-linking is completed, desired microcapsules can be obtained in the form of a slurry. Thereafter, if necessary, the microcapsules can be recovered as a solid content according to a known solid-liquid separation method such as filtration or centrifugation. In addition, the microcapsules can be washed as necessary.
2. Addition of enzyme By adding an enzyme to the ink dispersion of 1-1 or 1-2, a part or all of the amphiphilic substance is decomposed.

  In the present invention, prior to the addition of the enzyme, the dispersion may be diluted to facilitate washing (replacement of the liquid). What is necessary is just to set a dilution degree suitably according to the kind etc. of dispersion liquid.

  Further, the pH of the dispersion can be adjusted in advance prior to the addition of the enzyme. For example, when an enzyme having an optimum pH of 7.0 is used, it is desirable to adjust the pH to a range of 5.0 to 9.0. Such pH adjustment can increase the efficiency of the enzyme reaction. The pH adjustment may be performed using a known pH adjuster such as hydrochloric acid, sulfuric acid, or sodium hydroxide.

  When adding an enzyme, it is desirable to add it with stirring. For the stirring, a known stirrer or the like may be used. After the addition of the enzyme (when a nonionic surfactant described later is added), the time necessary for sufficient decomposition of the amphiphile (for example, 24 hours or more, preferably 24 to 48 hours) It is desirable to leave it still.

  After the addition of the enzyme, a nonionic surfactant can be added as a dry aggregation inhibitor as necessary. By adding a nonionic surfactant, aggregation of particles during drying can be prevented. As the nonionic surfactant, a known or commercially available one can be used. For example, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene hydrogenated castor oil, ether type such as polyoxyethylene alkyl thioether, polyoxyethylene mono fatty acid ester, polyoxyethylene difatty acid ester, polyoxyethylene propylene glycol Examples include fatty acid esters, propylene glycol fatty acid esters, polyoxyethylene sorbitan monofatty acid esters, glycerin monofatty acid esters, ester types such as sucrose fatty acid esters, and alkanolamide types such as polyoxyethylene alkylamides.

  The addition amount of the nonionic surfactant is usually 0.02 to 200 parts by weight, particularly preferably 0.2 to 20 parts by weight with respect to 1 part by weight of the amphiphilic substance.

  After the decomposition of the amphiphile is completed, the dispersion may be concentrated by decantation as necessary. Further, after the concentration step, a series of steps (purification step) of 1) dilution with water, 2) stirring and 3) standing can be repeated once or twice as necessary. Thereafter, the fine particles can be recovered as a dry powder through further steps such as solid-liquid separation and drying.

  Examples and comparative examples are shown below to further clarify the features of the present invention. In addition, this invention is not limited to an Example.

Examples 1-4 and Comparative Examples 1-7
Preparation of Dispersion Using each component shown in Table 1, (a) a thermochromic composition emulsion or (b) a microencapsulated thermochromic composition slurry was prepared by the following procedure. In Table 1, (a) indicates that the capsule wall material is not used, and (b) indicates that the capsule wall material is used.
(A) Preparation of thermochromic composition emulsion 1) Heat the color former (electron-donating compound), developer (electron-accepting compound) and desensitizer (volatile hydrophobic organic medium) at 120 to 180 ° C. Dissolve.

  2) In the emulsifier aqueous solution heated to 60 to 80 ° C., the solution of the above 1) at 70 to 100 ° C. is uniformly dissolved with medium shear stirring.

3) An O / W emulsion having an average particle diameter of about several μm is obtained by performing high shear stirring.
(B) Preparation of microencapsulated thermochromic composition slurry 1) 120-180 coloring agent (electron-donating compound), developer (electron-accepting compound) and desensitizer (volatile hydrophobic organic medium). Dissolve by heating at ℃.

  2) The capsule wall raw material and the dissolution aid are mixed, and the solution of 1) at 70 to 100 ° C. is added thereto and dissolved uniformly.

  3) The solution of 2) above is added to the aqueous emulsifier solution heated to 30 to 60 ° C. with medium shear stirring.

  4) An O / W emulsion having an average particle size of about several μm is obtained by performing high shear stirring.

  5) After switching to low shear stirring, the aqueous crosslinking agent solution is gradually added dropwise.

  6) After reacting at 60-90 ° C. for 3-12 hours, cooling to room temperature gives a slurry in which μm capsules are dispersed.

Collection of fine particles The particles were collected from the emulsion obtained in (a) or the slurry obtained in (b) by the following procedure.

  1) The emulsion obtained in (a) or the slurry obtained in (b) is diluted 10 times with hot water at 30 to 60 ° C.

  2) Adjust to pH 5-6 with aqueous sulfuric acid solution.

  3) Add enzyme and stir for more than 30 minutes.

  4) Add nonionic surfactant and stir for 30 minutes or more.

  5) After standing to cool overnight or more, a concentrated emulsion or concentrated slurry is obtained by decantation.

  6) A purified emulsion or purified slurry is obtained by repeating a series of purification steps of dilution, stirring, standing and decantation with respect to the concentrated emulsion or concentrated slurry.

  7) The concentrated emulsion (or purified emulsion) or concentrated slurry (or purified slurry) is suction filtered and dried to obtain fine particles.

  In the above 6) and 7), the number of purification steps required until the fine particles were easily loosened with a finger and became a smooth powder was examined. The results are shown in Table 1.

  As can be seen from Table 1, gum arabic was used as an emulsifier, and cellulase was decomposed at the time of recovery of the emulsions in Examples 1 and 2, gelatin was used as the emulsifier, and a microcapsule was decomposed at the time of recovery. In Example 3 and Example 4, it was found that the aggregation was easy to be solved with one purification.

  In Comparative Examples 1 to 4 carried out under the same conditions as in Examples 1 to 4 except that the enzymatic decomposition treatment was not carried out, despite the addition of a dry aggregation inhibitor (nonionic activator), In order to achieve a state where aggregation can be easily solved, the number of purifications has to be 3 times.

  Moreover, in Comparative Examples 5 to 7 using an emulsifier that is not decomposed by an enzyme, the number of purifications is set to make the aggregation easy to unravel despite the addition of a dry aggregation inhibitor (nonionic activator). It had to be 3 or 5 times.

Claims (5)

A part or all of the amphiphilic substance is decomposed by adding an enzyme that decomposes the amphiphilic substance to a dispersion in which fine particles stabilized by the amphiphilic substance are dispersed in a solvent. A method for producing fine particles, comprising the step of: The dispersion is obtained by dispersing a thermochromic composition containing 1) a color former (electron-donating color-forming organic compound), a developer (electron-accepting compound) and a desensitizer in a solvent, or 2) The production method according to claim 1, wherein the microcapsules containing the composition are dispersed in a solvent. The production method according to claim 1 or 2, wherein the solvent is water or an aqueous solvent. The manufacturing method in any one of Claims 1-3 whose amphiphile is at least 1 sort (s) of polysaccharide and protein. The manufacturing method in any one of Claims 1-4 which further has the process of removing one part or all part of a solvent.