JP2003144904A - Microcapsule and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microcapsule capable of being manufactured without using an organic solvent, and a method for manufacturing the same. SOLUTION: In the method for manufacturing the microcapsule by dispersing a mixture of a core substance and a self-dispersible urethane prepolymer of which the viscosity measured at 60 deg.C by a BM-type viscometer is 100-100,000 mPa.s in an aqueous medium, the mixture is dispersed in the aqueous medium without adding the organic solvent to the mixture.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a microcapsule and a method for producing the same, more specifically, a method for producing a microcapsule which can be prepared without using an organic solvent, and a microcapsule obtained by the method. It is about.

[0002]

2. Description of the Related Art A conventional microcapsule using a self-dispersing urethane resin is prepared by dispersing a mixture containing a core substance, a self-dispersing urethane prepolymer and an organic solvent for dissolving the urethane prepolymer in an aqueous medium. Was prepared by As the organic solvent, for example, acetone, methyl ethyl ketone, ethyl acetate, benzene, etc. have been used.

[0003]

However, since these organic solvents have a low boiling point and high volatility, it has been pointed out that a worker needs to pay attention to safety and hygiene. In addition, since these organic solvents need to be recovered during the process of manufacturing the microcapsules, flammable solvent vapor is generated during distillation for this recovery, which is not preferable from the viewpoint of safety. It had been. Further, it has been pointed out that the necessity of providing this organic solvent recovery step complicates the manufacturing process, lengthens the time required for manufacturing, and requires cost.

Further, when a volatile substance is used as the core substance, the volatile substance is also recovered together with the solvent in the solvent recovery step, so that there is a problem that microcapsules of the volatile substance cannot be produced.

The present invention has been made to solve the problems of the prior art, and an object of the present invention is to provide a microcapsule which can be produced without using an organic solvent. Is. Another object of the present invention is to provide a method for producing such microcapsules.

[0006]

The method for producing microcapsules according to the present invention comprises a core substance and a BM type viscometer at 60 ° C.
A method for producing microcapsules in which a mixture with a self-dispersing urethane prepolymer having a viscosity of 100 to 100,000 mPa · s is dispersed in an aqueous medium, wherein the mixture does not contain an organic solvent. Characterize. The microcapsule of the present invention is characterized by being obtained by the above production method.

By using the self-dispersing urethane prepolymer having such a viscosity range, the mixture of the core substance and the self-dispersing urethane prepolymer is simply dispersed in an aqueous medium, and the polyurethane is prepared without using an organic solvent. Microcapsules made of resin can be obtained.

According to the present invention, when the mixture of the core substance and the self-dispersing urethane prepolymer is dispersed in the aqueous medium, a polyvalent amine is added to the aqueous medium, and the polyamine is crosslinked. It is characterized by Such amine cross-linking makes it possible to obtain a strong capsule.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a self-dispersing urethane prepolymer is used as a raw material for a wall material of microcapsules. As such a self-dispersing urethane prepolymer, for example, (a) a polyol compound having two or more hydroxyl groups, and (b) a polyisocyanate compound having two or more isocyanate groups,
(C) a compound having a hydroxyl group or an amino group and an ionic salt forming group and / or a nonionic hydrophilic group in the molecule, (d)
When the above (c) has an ionic salt forming group, a terminal isocyanate type or terminal hydroxyl group type prepolymer prepared from the corresponding salt forming agent can be mentioned.

Examples of the polyol (a) having two or more hydroxyl groups include ethylene glycol, diethylene glycol, butanediol, propylene glycol, hexanediol, bisphenol A, bisphenol S,
Hydrogenated bisphenol A, dibromobisphenol A, 1,4-cyclohexanedimethanol, dihydroxyethyl terephthalate, hydroquinone dihydroxyethyl ether, trimethylolpropane, glycerin, pentaerythritol and other polyhydric alcohols, their alkylene derivatives or their polyhydric alcohols. And alkylene derivative and polyvalent carboxylic acid, polyvalent carboxylic acid anhydride, or esterified product from polyvalent carboxylic acid ester, polycarbonate polyol, polytetramethylene glycol, polycaprolactone polyol, polybutadiene polyol, polythioether polyol, polyacetal polyol, castor Examples include polyol compounds such as oil polyols.

Examples of the polyisocyanate compound having two or more isocyanate groups (b) include, for example,
Tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, naphthylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated toluene diisocyanate, tetramethylene xylylene diisocyanate and burettes and isocyanurates of these isocyanates All aromatics conventionally used,
Examples thereof include aliphatic or alicyclic isocyanates alone or as a mixture.

Examples of the compound (c) having a hydroxyl group or an amino group and an ion salt forming group in the molecule include, for example,
Examples thereof include compounds having a salt-forming carboxylic acid or sulfonic acid group, and specifically, for example, glycolic acid, malic acid, glycine, aminobenzoic acid, alanine,
Examples thereof include hydroxy acids such as dimethylolpropionic acid, aminocarboxylic acids, polyhydric hydroxy acids, aminosulfonic acids such as taurine, sulfamic acid and 2-hydroxyethanesulfonic acid, and hydroxysulfonic acids. The corresponding salt-forming agent (d) includes:
Examples thereof include monovalent metal hydroxides such as sodium hydroxide and potassium hydroxide, and tertiary amine compounds such as ammonia, trimethylamine and triethylamine.

The compound (c) having a hydroxyl group or an amino group and an ion salt-forming group in the molecule is, for example, an alkoxylated amine such as N, N-dimethylethanolamine or N-methyldiethanolamine, or N-. Methyl-N- (3-aminopropyl) -ethanolamine,
Amino alcohols such as N, N-dimethylhydrazine and amines are also included. Examples of the corresponding salt-forming agent (d) include, for example, organic and inorganic acids such as hydrochloric acid, nitric acid, formic acid, acetic acid, diethylsulfate, methyl chloride, benzyl chloride, xylylene dichloride, and halogen atoms that cause a quaternization reaction. Alternatively, a compound containing an ester of a corresponding strong acid may be mentioned.

Examples of the compound (c) having a hydroxyl group and / or an amino group and a nonionic hydrophilic group in the molecule include monoalcohol or polyhydric alcohol ethylene oxide alone or ethylene oxide and propylene oxide adducts. Can be mentioned.

When (c) is anionic, (a)
+ (B) + (c) has an acid value of 10 mg · KOH / g to 50
It is preferable to set the concentration of (c) so as to be in the range of mg · KOH / g. When (c) is cationic,
The amine value of (a) + (b) + (c) is 10 to 50 mg.
It is preferable to set the concentration of (c) so as to be in the range of KOH / g. When (c) is nonionic, (a)
The concentration of the nonionic group of + (b) + (c) is 1 by weight.
It is preferable to set the concentration of (c) so as to be in the range of 0% to 30%.

In the present invention, the self-dispersing urethane prepolymer has a viscosity of 1 at 60 ° C. measured by a BM type viscometer.
It is from 00 to 100,000 mPa · s and contains no organic solvent. If the viscosity is out of the above range, microcapsules cannot be substantially prepared, which is not preferable.

The molecular weight of the self-dispersible urethane prepolymer in the present invention is preferably in the range of 300 to 5,000. If the molecular weight is out of this range, the urethane prepolymer is substantially in the above viscosity range, which is not preferable.

Further, the number of branches per 1,000 of the molecular weight of the self-dispersing urethane prepolymer is preferably 2 or less. When the number of branches is 2 or more, the urethane prepolymer is substantially not in the viscosity range, which is not preferable.

In the present invention, a polyvalent amine can be used as a chain extender. Examples of the polyvalent amine include ethylenediamine, propylenediamine, diethylenetriamine, hexylenediamine, triethylenetetramine, tetraethylenepentamine, isophoronediamine, xylylenediamine, diphenylmethanediamine,
Examples thereof include hydrogenated diphenylmethanediamine and the like. The amount of the chain extender added is preferably equal to or less than the equivalent amount of the isocyanate group of the isocyanate-terminated urethane prepolymer.

In the present invention, it is not necessary to add an organic solvent for dilution used in the preparation of the self-dispersing urethane prepolymer in the prior art. For example, in the prior art, low boiling organic solvents such as acetone, methyl ethyl ketone, ethyl acetate and benzene are used,
Generally, methyl ethyl ketone has been preferred. However, in the present invention, 6 by the BM type viscometer
Since the self-dispersing urethane prepolymer having a viscosity at 0 ° C. of 100 to 100,000 mPa · s is used, microcapsules can be obtained without using such an organic solvent.

As the aqueous medium, water or water in which various additives are dissolved can be used. As an additive to be dissolved in an aqueous medium, in addition to the polyvalent amine compound, the salt-forming agent (neutralizing agent) of the self-dispersing urethane prepolymer, an emulsifier, a dispersant, a surfactant, a protective colloid agent, a thickening and stabilizing agent. Agents, antiseptics, antifreezing agents, etc., and these additives are appropriately selected and added as necessary.

In the present invention, a colorant, a dye, an oil, a pigment, a fragrance, an adhesive, a physiologically active substance, a repellent, a flame retardant, a deodorant, a plant essential oil, etc. may be used as the core substance. it can. These core substances are not limited to liquids and may be solids. Moreover, you may use what melt | dissolved these core substances in the non-volatile oil as a core substance.

In the present invention, since the organic solvent is not used as described above, it is not necessary to go through the recovery step thereof, and therefore it is possible to use the volatile substance as the core substance. Examples of volatile substances are fragrances, deodorants,
Examples include plant essential oils and volatile agricultural chemicals. As a fragrance,
Various natural flavors and synthetic flavors can be mentioned. Examples of natural flavors include bouquets, roses, eucalyptus, lavender,
Examples include fragrances extracted from jasmine, lemon, various herbs, and the like. Further, as the synthetic fragrance, for example, "13599 chemical products" issued by Kagaku Kogyo Nippo (1999)
1287 to 1341. Examples of the deodorant include deodorants derived from natural products and synthetic deodorants. Examples of plant essential oils include cypress oil, hiba oil, wasabi oil, cedar oil, moon peach oil, citrus oil, ginger oil, allyl isothiocyanate and the like. Examples of volatile pesticides include "Agricultural Chemicals Handbook" (1998) published by the Japan Plant Protection Association.
Among the pesticides described in 1., the vapor pressure at 25 ° C is 1 × 10
^-4 Pa or more.

The concentration range of the core substance is 50% with respect to the microcapsule dispersion liquid containing the finally obtained aqueous medium.
The following is preferable. If the concentration is higher than this, emulsification becomes difficult and the viscosity increases, which is not preferable.
Even if it is 0.1% or less, microcapsules can be prepared without any problems, but the concentration of the target core substance becomes too low, which is not practical from an economical point of view.

The ratio of the core substance to the self-dispersing urethane prepolymer is preferably 1000% or less by weight. 1
If it is 000% or more, the emulsification becomes poor, which is not preferable. The lower this ratio, the smaller the particle size of the microcapsules.

In the present invention, microcapsules can be prepared by the following procedure. First, a self-dispersing urethane prepolymer is prepared from the components (a), (b), (c) and (d) described above. The core substance may be added together at the time of preparing this prepolymer. The component (d) may be added in the next step. The reaction for preparing the self-dispersing urethane prepolymer is performed under a nitrogen stream, and if necessary, in the presence of a catalyst, at 30 ° C to 120 ° C for 1 to 30 hours.

Next, the core material is mixed with the self-dispersing urethane prepolymer. At this point, the component (d) may be mixed as described above. Finally, the above mixture is added to the aqueous medium and mixed. On the contrary, an aqueous medium may be added to and mixed with the above mixture. Mixing and stirring are performed by a known method. For example, an anchor-type, paddle-type, turbine-type, or other agitator, a homodisper, a homomixer, a line mixer, or other emulsifier may be used. Further, if a polyvalent amine compound is added at the time of this mixing and stirring to carry out a crosslinking reaction, stronger microcapsules can be obtained. A surface active agent or a protective colloid agent may be supplementarily added to assist the microencapsulation.

According to the present invention, several tens of μm to several tens of nm
Microcapsules with particle sizes in the range of are prepared. An appropriate particle size range may be set according to the application of the microcapsules. When a volatile substance is used as the core substance to form sustained release microcapsules, it is preferable to prepare microcapsules having a relatively large particle size. When the microcapsules are used by diluting, it is preferable to use microcapsules of 100 nm or less from the viewpoint of sedimentation stability.

[0029]

EXAMPLES Synthesis examples and comparative synthesis examples of self-dispersing urethane prepolymers used in Examples and Comparative Examples described later are shown below.

(Synthesis Example 1) Synthesis of Self-Dispersing Urethane Prepolymer The self-dispersing urethane prepolymer of Synthesis Example 1 was synthesized according to the following formulation and the following procedure.

[0031]   (A) 250 parts by weight of polypropylene glycol having a molecular weight of 1000   (B) Isophorone diisocyanate 168 parts by weight         Catalyst: dibutyltin dilaurate 0.02 parts by weight   (C) 37 parts by weight of dimethylolbutanoic acid   (D) Triethylamine 25 parts by weight.

(A) component in a reaction vessel equipped with a nitrogen introducing pipe,
Charge component (b) and catalyst, and stir at 70 ° C for 3
Reacted for 0 minutes. Then, the component (c) was charged and 100
The reaction was carried out at 0 ° C for 1 hour. Then cool to 70 ° C,
The component (d) was charged and reacted at the same temperature for 30 minutes to obtain a self-dispersible urethane prepolymer of this synthesis example.

The molecular weight of this self-dispersing urethane prepolymer was 1,586, and the number of branches per 1,000 molecular weight was 0. Moreover, the viscosity at 60 ° C. measured by a BM type viscometer is 1
It was 3,000 mPa · s.

Comparative Synthesis Example 1 Synthesis of Self-Dispersing Urethane Prepolymer 60 by BM type viscometer with the following composition and the following procedure.
Viscosity at ℃ is 50,000mPa · s or more, molecular weight is 5,
An attempt was made to synthesize a urethane prepolymer having a number of branches of 000 or more and a number of branches of 2 or more per 1000 of molecular weight without using an organic solvent for diluting the resin. However, the operation became impossible on the way due to the increase in viscosity.

[0035]   (A) 40 parts by weight of trimethylolpropane   (B) Isocyanurate-modified hexamethylene                         Diisocyanate trimer 454 parts by weight         Catalyst: dibutyltin dilaurate 0.03 parts by weight   (C) 30 parts by weight of dimethylolbutanoic acid   (D) 20 parts by weight of triethylamine.

The component (a) is added to a reaction vessel equipped with a nitrogen introducing pipe,
Charge component (b) and catalyst and stir at 70 ° C. for 6 hours.
The reaction was carried out for 0 minutes. Subsequently, the component (c) was charged and 1
When the reaction was carried out at 00 ° C. for 60 minutes, the reaction product lost its fluidity and could not be stirred, and it became impossible to continue the subsequent operations. At this point, the viscosity at 60 ° C. measured by a BM type viscometer was 100,000 mPa · s or more, and measurement was impossible. Calculated molecular weight of self-dispersing urethane prepolymer is 5436, molecular weight 100
The number of branches per 0 was 2.2.

Comparative Synthesis Example 2 Synthesis of Self-Dispersing Urethane Prepolymer A self-dispersing urethane prepolymer of Comparative Synthesis Example 2 was synthesized according to the following formulation and the following procedure. It differs from Comparative Synthesis Example 1 in that methyl ethyl ketone is used as an organic solvent for diluting the resin.

[0038]   (A) 40 parts by weight of trimethylolpropane   (B) Isocyanurate modification           Hexamethylene diisocyanate trimer 454 parts by weight         Catalyst: dibutyltin dilaurate 0.03 parts by weight         Organic solvent: Methyl ethyl ketone 1632 parts by weight   (C) 30 parts by weight of dimethylolbutanoic acid   (D) 20 parts by weight of triethylamine.

(A) component in a reaction vessel equipped with a nitrogen introducing tube,
The component (b), the catalyst and methyl ethyl ketone as an organic solvent were charged, and the reaction was carried out at 70 ° C. for 60 minutes while stirring. Subsequently, the component (c) was charged and reacted at 70 ° C. for 60 minutes. Further, (d) was charged and reacted at the same temperature for 30 minutes to prepare a methyl ethyl ketone solution of a self-dispersing urethane prepolymer. The calculated self-dispersing urethane prepolymer has a molecular weight of 5436, and the number of branches per 1000 of the molecular weight is 2.2. BM when organic solvent is not contained by distilling off methyl ethyl ketone by vacuum distillation
Attempted to measure the viscosity at 60 ° C with a Brookfield viscometer.
It was more than 30,000 mPa · s and could not be measured.

(Synthesis Example 2) Synthesis of Self-Dispersing Urethane Prepolymer A self-dispersing urethane prepolymer of Synthesis Example 2 was synthesized by the following composition and the following procedure.

[0041]   (A) 250 parts by weight of polybutylene adipate having a molecular weight of 2000   (B) 63 parts by weight of hexamethylene diisocyanate         Catalyst: dibutyltin dilaurate 0.02 parts by weight   (C) N-methyldiethanolamine 15 parts by weight   (D) 8 parts by weight of acetic acid.

In a reaction vessel equipped with a nitrogen introducing pipe, the component (a), (b)
Components) and a catalyst were charged and the reaction was carried out at 70 ° C. for 30 minutes while stirring. Subsequently, the component (c) was charged, and the temperature was 70 ° C.
And reacted for 3 hours. Then cool to 60 ° C., (d)
The components were charged and reacted at the same temperature for 30 minutes to obtain a self-dispersing urethane prepolymer of this synthesis example. The calculated molecular weight of this self-dispersing urethane prepolymer is 268.
3, the calculated number of branches per 1000 molecular weight was 0. Also, the viscosity at 60 ° C. measured by a BM type viscometer is 9,
It was 500 mPa · s.

(Synthesis Example 3) Synthesis of Self-Dispersing Urethane Prepolymer A self-dispersing urethane prepolymer of Synthesis Example 3 was synthesized according to the following formulation and the following procedure.

[0044]   (A) 200 parts by weight of polybutylene adipate having a molecular weight of 2000   (B) 89 parts by weight of isophorone diisocyanate         Catalyst: dibutyltin dilaurate 0.02 parts by weight   (C) 13 parts by weight of dimethylolpropionic acid   (D) Triethylamine 10 parts by weight.

Component (a), (b
Components) and a catalyst were charged, and the reaction was carried out at 70 ° C. for 30 minutes while stirring. Then, the component (c) was charged and 100
The reaction was carried out at 0 ° C for 1 hour. Then cool to 60 ° C,
The component (d) was charged and reacted at the same temperature for 30 minutes to obtain a self-dispersible urethane prepolymer of this synthesis example. The calculated molecular weight of this self-dispersing urethane prepolymer was 3128, and the calculated number of branches per 1000 of the molecular weight was 0.3. The viscosity at 60 ° C. measured by a BM type viscometer was 8,000 mPa · s.

Example 1 Preparation Example of Microcapsules of Methyl Bromide (Agricultural Chemicals) Microcapsules of Example 1 were prepared according to the following formulation and the following procedure.

[0047]   Liquid (A): 10.0 parts by weight of the urethane prepolymer of Synthesis Example 1             Core substance: methyl bromide (agrochemical) 10.0 parts by weight   Liquid (B): 79.9 parts by weight of distilled water             0.1 parts by weight of ethylenediamine.

First, the components of the liquid (A) were heated and dissolved. Next, the solution (B) was dissolved with stirring (A)
The liquids were mixed and reacted at 40 ° C. for 5 hours for microencapsulation. The median diameter of microcapsules is 5
It was 0 nm. The concentration of methyl bromide in the obtained microcapsule dispersion was 10%.

The resulting microcapsule dispersion is triturated with water.
No sedimentation of microcapsules was observed even when diluted 0 times and allowed to stand for 2 hours.

Comparative Example 1 Preparation Example of Microcapsules of Methyl Bromide (Agrochemical) For comparison, the urethane prepolymer of Comparative Synthesis Example 2 containing methyl ethyl ketone as an organic solvent was used to prepare microcapsules of methyl bromide (agrochemical). Attempts were made to prepare capsules. That is, the microcapsules of Comparative Example 1 were prepared according to the following formulation and the following procedure.

[0051]   Liquid (A): Self-dispersing urethane of Comparative Synthesis Example 2               Methyl ethyl ketone solution of prepolymer 40.0 parts by weight             Core substance: methyl bromide (agrochemical) 10.0 parts by weight   Liquid (B): 80.0 parts by weight of distilled water.

First, the components of the liquid (A) were heated and dissolved. Next, the solution (B) was dissolved with stirring (A)
The liquids were mixed and reacted at 40 ° C. for 5 hours for microencapsulation. Subsequently, methyl ethyl ketone was recovered by vacuum distillation. At this time, since most of the methyl bromide that is the core substance was evaporated together with methyl ethyl ketone, methyl bromide did not remain in the obtained microcapsule slurry, and thus it was not possible to prepare methyl bromide microcapsules. could not.

Example 2 Preparation Example of Microcapsule of Lavender Oil (Plant Essential Oil) A microcapsule of Example 2 was prepared according to the following formulation and the following procedure.

[0054]   Liquid (A): 10.0 parts by weight of the urethane prepolymer of Synthesis Example 1             Core substance: Lavender oil (vegetable essential oil) 10.0 parts by weight   Liquid (B): 79.9 parts by weight of distilled water             0.1 parts by weight of ethylenediamine.

First, the components of the liquid (A) were heated and dissolved. Next, the solution (B) was dissolved with stirring (A)
The liquids were mixed and reacted at 40 ° C. for 3 hours for microencapsulation. Microcapsule median diameter is 8
A microcapsule having a size of 0 nm and containing lavender oil was obtained.

Example 3 Preparation Example of Dye Microcapsule A microcapsule of Example 3 was prepared according to the following formulation and the following procedure.

[0057]   Liquid (A): 15.0 parts by weight of urethane prepolymer of Synthesis Example 1             Core substance: 15.0 parts by weight of oil in which 2% of SPILON GREEN is dissolved   Liquid (B): 69.85 parts by weight of distilled water             Ethylenediamine 0.15 parts by weight.

First, the components of the liquid (A) were heated and dissolved. Next, the solution (B) was dissolved with stirring (A)
The liquids were mixed and reacted at 40 ° C. for 3 hours for microencapsulation. The median diameter of microcapsules is 3
0 nm, microcapsules containing the dye were obtained.

Example 4 Preparation Example of Allyl Isothiocyanate Microcapsules An example of preparation of microcapsules using allyl isothiocyanate which is the main component of horseradish oil will be shown. That is, the microcapsules of Example 4 were prepared according to the following formulation and the following procedure.

[0060]   Liquid (A): 10.0 parts by weight of urethane prepolymer of Synthesis Example 2             Core substance: allyl isothiocyanate 30.0 parts by weight   Liquid (B): 68.7 parts by weight of distilled water             0.1 parts by weight of ethylenediamine             Emulsifier: Sodium dodecylbenzene sulfonate 1.0 part by weight             Thickener: Xanthan gum 0.2 parts by weight.

First, the components of the liquid (A) were heated and dissolved. Next, the solution (B) was dissolved with stirring (A)
The liquids were mixed and reacted at 40 ° C. for 5 hours for microencapsulation. The median diameter of microcapsules is 3
μm and microcapsules containing allyl isothiocyanate were obtained. The content of allyl isothiocyanate in the obtained microcapsule slurry was 30%.
Met.

Comparative Example 2 Preparation Example of Allyl Isothiocyanate Microcapsules For comparison, an attempt was made to prepare allyl isothiocyanate microcapsules using the urethane prepolymer of Comparative Synthesis Example 2 containing methyl ethyl ketone as an organic solvent. That is, the preparation of the microcapsules of Comparative Example 2 was tried by the following formulation and the following procedure.

[0063]   Liquid (A): 20.0 parts by weight of urethane prepolymer of Comparative Synthesis Example 2             Core substance: allyl isothiocyanate 30.0 parts by weight   Liquid (B): 68.8 parts by weight of distilled water             Emulsifier: Sodium dodecylbenzene sulfonate 1.0 part by weight             Thickener: Xanthan gum 0.2 parts by weight.

First, the components of the liquid (A) were heated and dissolved. Next, the solution (B) was dissolved with stirring (A)
The liquids were mixed and reacted at 40 ° C. for 5 hours for microencapsulation. Subsequently, methyl ethyl ketone was recovered by vacuum distillation. At this time, since most of allyl isothiocyanate as a core substance was evaporated together with methyl ethyl ketone, allyl isothiocyanate did not remain in the obtained microcapsule slurry, and thus microcapsules containing allyl isothiocyanate were prepared. I couldn't do that.

Example 5 Preparation Example of Carbon Black Microcapsule A preparation example of a microcapsule using solid carbon black as a core substance will be shown. That is, the microcapsules of Example 5 were prepared according to the following formulation and the following procedure.

[0066]   Liquid (A): 20.0 parts by weight of urethane prepolymer of Synthesis Example 3             Core material: carbon black 1.0 part by weight   Solution (B): distilled water 78.8 parts by weight             0.2 parts by weight of diethylenetriamine.

First, the components of the liquid (A) were heated and dissolved. Next, the solution (B) was dissolved with stirring (A)
The liquids were mixed and reacted at 30 ° C. for 3 hours to carry out microencapsulation. The median diameter of microcapsules is 6
μm and microcapsules containing carbon black were obtained.

Example 6 Preparation Example of Allyl Caproate Microcapsules A preparation example of microcapsules containing allyl caproate microcapsules as a core substance will be described. That is, the microcapsules of Example 6 were prepared according to the following formulation and the following procedure.

[0069]   Liquid (A): 20.0 parts by weight of urethane prepolymer of Synthesis Example 2             Core substance: Allyl caproate 10.0 parts by weight   Liquid (B): distilled water 60.0 parts by weight             0.2 parts by weight of ethylenediamine.

First, the components of the liquid (A) were heated and dissolved. Next, the solution (B) was dissolved with stirring (A)
The liquids were mixed and reacted at 40 ° C. for 5 hours for microencapsulation. Microcapsule median diameter is 8
μm and microcapsules containing allyl caproate were obtained.

As described above, according to Examples 1 to 6,
It can be seen that microcapsules having not only a liquid but also a solid substance as a core substance can be obtained. Further, from the comparison between Example 1 and Comparative Example 1 and the comparison between Example 4 and Comparative Example 2, each Example does not include the step of recovering the organic solvent, so that even if it is a volatile substance, it is microencapsulated. It is clear that you can.

[0072]

EFFECTS OF THE INVENTION Since an organic solvent having a low boiling point and high volatility is not used, safety and hygiene problems such as the worker inhaling vapor gas of the organic solvent are solved, and the working environment is greatly improved. Also, since it does not use highly flammable organic solvents,
The safety during manufacturing can also be improved. Furthermore,
It is not necessary to provide an organic solvent recovery step during the manufacturing process of microcapsules, the manufacturing process and manufacturing equipment are simplified, the time required for manufacturing is shortened compared to the past, and the manufacturing cost can be significantly proposed. Became. In addition, the elimination of the organic solvent recovery process eliminates any loss of the volatile substance during the solvent recovery process even when the volatile substance is used as the core substance, and the microcapsule using the volatile substance as the core substance is eliminated. Can be manufactured.

Continued front page    F-term (reference) 4C083 AA122 AD071 AD072 BB21                       BB41 CC01 DD14 FF01                 4G005 AA01 AB13 AB14 AB25 BA02                       BB02 BB11 DA02X DA09W                       DB02Y DB12W DB21X DB22X                       DB27X DB30W DB30X DC15Y                       DC26Y DC36X DC42Y DC46Y                       DC51Y DC52W DC67Y DD23Y                       DD24Y DD38Y DD38Z EA01                       EA02 EA03 EA05 EA06 EA08                 4J040 JA11 PA21 PA25 PA29 PA38                       PA44

Claims (16)

[Claims] 1. A method for producing microcapsules, which comprises dispersing a mixture of a core substance and a self-dispersible urethane prepolymer having a viscosity of 100 to 100,000 mPa · s at 60 ° C. by a BM type viscometer in an aqueous medium. The method for producing microcapsules is characterized in that the mixture does not contain an organic solvent. 2. The method for producing microcapsules according to claim 1, wherein the molecular weight of the self-dispersing urethane prepolymer is in the range of 300 to 5,000. 3. The method for producing microcapsules according to claim 1, wherein the number of branches per 1,000 of the molecular weight of the self-dispersing urethane prepolymer is 2 or less. 4. When the mixture of the core substance and the self-dispersing urethane prepolymer is dispersed in the aqueous medium, a polyvalent amine is added to the aqueous medium, and crosslinking with the polyvalent amine is performed. The method for producing the microcapsule according to claim 1. 5. The method for producing microcapsules according to claim 1, wherein the core substance is a volatile substance. 6. The method for producing a microcapsule according to claim 1, wherein the core substance is a liquid. 7. The method for producing microcapsules according to claim 1, wherein the core substance is a solid. 8. The core material is a colorant, a dye, an oil,
Pigments, fragrances, adhesives, bioactive substances, repellents, flame retardants,
The method for producing microcapsules according to any one of claims 1 to 7, which is a substance selected from a deodorant and a vegetable essential oil. 9. Microcapsules obtained by dispersing a mixture of a core substance and a self-dispersing urethane prepolymer having a viscosity of 100 to 100,000 mPa · s at 60 ° C. by a BM type viscometer in an aqueous medium. The microcapsules are characterized in that the mixture does not contain an organic solvent. 10. The microcapsule according to claim 9, wherein the molecular weight of the self-dispersing urethane prepolymer is in the range of 300 to 5,000. 11. The number of branches per 1,000 molecular weight of the urethane resin after polymerization in the microcapsules is 2
The microcapsule according to claim 9 or 10, characterized in that: 12. When dispersing the mixture of the core substance and the self-dispersing urethane prepolymer in the aqueous medium,
The polyvalent amine is added to the aqueous medium, and crosslinking is performed by the polyvalent amine.
1. The microcapsule according to any one of 1. 13. The microcapsule according to claim 9, wherein the core substance is a volatile substance. 14. The microcapsule according to claim 9, wherein the core substance is a liquid. 15. The microcapsule according to claim 9, wherein the core substance is solid. 16. The core substance is a substance selected from colorants, dyes, oils, pigments, fragrances, adhesives, physiologically active substances, repellents, flame retardants, deodorants, and plant essential oils. The microcapsule according to any one of claims 1 to 15.