JPH09117658A - Manufacture of microcapsule dispersion and manufacture of microcapsule - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a microcapsule having high membrane strength at low cost by a method wherein an aqueous solution containing an initial condensate of aminoplast resin and an aqueous solution containing water soluble substances are mixed together to prepare a mixed aqueous solution, and the mixed aqueous solution is emulsified and dispersed in a hydrophobic solvent in the presence of dispersant, heated and agitated. SOLUTION: For manufacturing a microcapsule dispersion, at first, an aqueous solution A containing an initial condensate of aminoplast resin is prepared and the solution A is mixed with an aqueous solution B containing water soluble substances to provide a mixed aqueous solution. Next the mixed solution is emulsified and dispersed in a hydrophobic solvent in the presence of dispersant and heated and agitated. And the initial consensate of aminoplast resin is polycondensed to form a film of aminoplast resin, whereby a microcapsule including solution B is manufactured. And then microcapsule dispersed liquid is mixed with an aqueous solution D containing water and a surface-active agent and emulsified and a hydrophobic solvent is removed to manufacture the objective microcapsule dispersion.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a microcapsule dispersion liquid containing a water-soluble substance, and more specifically,
Method for producing a microcapsule dispersion liquid capable of stably producing a microcapsule having a water-soluble substance as a core substance and an aminoplast resin as a coating material by a W / O type in situ polymerization method in the presence of a dispersant It is about.

[0002]

2. Description of the Related Art Conventionally, for microcapsules containing water or a water-soluble compound as a core substance, for example, a method for producing a microencapsulated heat storage material (JP-A-61-1).
No. 92785), a method for producing microcapsules (Japanese Patent Laid-Open No. 63-88033), and various other microcapsules have been proposed.

[0003]

Since the microcapsules obtained by the method for producing the microencapsulated heat storage material (Japanese Patent Laid-Open No. 61-192785) are produced by the interfacial polymerization method, the film thickness is reduced. As a result, it has a drawback that the strength of the microcapsules is poor.

On the other hand, in the above-mentioned method for producing microcapsules (Japanese Patent Laid-Open No. 63-88033), yeast is used as the coating material for coating the core substance, and therefore it is easily putrefactive, expensive and impractical. It has drawbacks.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for producing a microcapsule having a low cost and excellent film strength and a dispersion thereof.

[0006]

In order to achieve the above-mentioned object, the present invention comprises a step of producing the following aqueous solution (A),
Mixing the aqueous solution (A) with the following aqueous solution (B) to prepare a mixed aqueous solution; emulsifying and dispersing the mixed aqueous solution in the presence of a dispersant in a hydrophobic solvent; The emulsion-dispersed system is heated and stirred to cause polycondensation reaction of the aminoplast resin initial condensate in the aqueous solution (A) to form an aminoplast resin coating film, thereby forming microcapsules containing the aqueous solution (B). First, a method for producing a microcapsule dispersion liquid, which includes a step of producing
The summary of the (A) An aqueous solution containing an aminoplast resin initial condensate. (B) An aqueous solution containing a water-soluble substance.

A second method is a method for producing a microcapsule from which a microcapsule is taken out from a microcapsule dispersion obtained by the method for producing a microcapsule dispersion, which is the first aspect.

Further, the microcapsule dispersion obtained by the above-mentioned method for producing a microcapsule dispersion is mixed with water or the following aqueous solution (D) to emulsify it, and then the hydrophobic solvent is removed to obtain an aqueous solvent. The third gist is a method for producing a microcapsule dispersion liquid in which the above microcapsules are dispersed. (D) An aqueous solution containing a surfactant or a water-soluble polymer compound.

A fourth aspect is a method for producing a microcapsule from which microcapsules are taken out from a microcapsule dispersion obtained by the method for producing a microcapsule dispersion which is the third aspect.

In the method for producing a microcapsule dispersion of the present invention, the aqueous solution (B) includes not only an aqueous solution containing a specific water-soluble substance, but also an aqueous solution (B) entirely consisting of water. .

That is, the present inventors have conducted a series of studies to achieve the above object. Then, in the course of the research, further research was conducted centering on the film-forming material for the microcapsules encapsulating the water-soluble substance and the manufacturing method of microencapsulation using the film-forming material. As a result, the aminoplast resin precondensate was used as the film-forming material, and the mixed aqueous solution of this aqueous solution and the aqueous solution containing the water-soluble substance as the core substance was emulsified and dispersed in the hydrophobic solvent containing the dispersant. Then, the system is heated and stirred to cause the polycondensation reaction of the aminoplast resin initial condensate to form a film made of an aminoplast resin to produce microcapsules containing a core substance. It was found that an excellent product can be obtained.

Particularly, the hydrophobic solvent has a boiling point of 30 to 30.
By using an aliphatic hydrocarbon or an alicyclic hydrocarbon at 200 ° C., it becomes easy to dry the microcapsules and to produce the water-soluble solvent microcapsule dispersion from the hydrophobic solvent microcapsule dispersion. .

From the viewpoint of dispersibility, the above-mentioned dispersants have a HLB (hydrophilic / lipophilic balance) of 3 to 15, and the compounds described below, sorbitan fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, poly It is preferable to use an oxyalkylene monoether type nonionic surfactant and a polyoxyalkylene monoester type nonionic surfactant.

The microcapsule dispersion obtained by the above-mentioned method for producing a microcapsule dispersion is mixed with water or an aqueous solution (D) containing a surfactant or a water-soluble polymer compound and emulsified. It has been found that by removing the hydrophobic solvent, a microcapsule dispersion liquid in which microcapsules are dispersed in an aqueous solvent can be easily produced.

[0015]

Next, the present invention will be described in detail.

In the method for producing a microcapsule dispersion of the present invention, first, an aqueous solution [amino acid (A)] containing an aminoplast resin initial condensate is produced, and this aqueous solution (A) and an aqueous solution containing a water-soluble substance [ Aqueous solution (B)] is mixed to prepare a mixed aqueous solution. Then, the mixed aqueous solution is emulsified and dispersed in a hydrophobic solvent in the presence of a dispersant, and the whole system in which the mixed aqueous solution is emulsified and dispersed is heated and stirred. Then, the aminoplast resin initial condensate in the aqueous solution (A) is subjected to polycondensation reaction (in-situ polymerization) to form an aminoplast resin coating film, thereby producing microcapsules containing the aqueous solution (B). In this way, the manufacturing process of the microcapsule dispersion liquid (W / O type microcapsule dispersion liquid) in which the microcapsules are dispersed in the hydrophobic medium is referred to as the first manufacturing process.

Subsequently, the W / O type microcapsule dispersion liquid is used, and the W / O type microcapsule dispersion liquid is mixed with water or an aqueous solution (D) containing a surfactant or a water-soluble polymer compound to be emulsified, followed by a hydrophobic solvent. Is removed to produce a microcapsule dispersion liquid in which the above microcapsules are dispersed in an aqueous solvent. Thus, the microcapsule dispersion liquid (W /
The manufacturing process of the W-type microcapsule dispersion liquid) is referred to as a second manufacturing process.

The aminoplast resin precondensate used in the above-mentioned production process is a film-forming material for microcapsules and is a resin precondensate obtained by a polymerization reaction of an amino compound and formaldehyde. The initial condensate in the present invention means a resin which is not completely resinified but shows a liquid state at room temperature and is usually available as a 50 to 80% aqueous solution. Specific examples of the initial condensate include a urea-formalin resin initial condensate, a melamine-formalin resin initial condensate, and a benzoguanamine-formalin resin initial condensate. Among them, it is preferable to use the initial condensate of melamine-formalin resin from the viewpoints of cost and strength of microcapsules.

The method for producing the aminoplast resin precondensate will be described by taking the melamine-formalin resin precondensate as an example. That is, melamine resin powder and formalin (37%
(Formaldehyde aqueous solution) is prepared, and melamine resin powder (a) and formalin (b) are used in a molar ratio of a: b =
Mix in a ratio of 1: 1 to 1: 4 and under weak alkaline,
Water-soluble melamine by heating above about 60 ℃
An aminoplast resin precondensate, which is a formalin resin precondensate, is obtained. In this production, melamine-
Although the formalin resin initial condensate has been described, other aminoplast resin initial condensates also conform to the above production.

In the aqueous solution [aqueous solution (B)] mixed with the aminoplast resin initial condensate and containing a water-soluble substance to be the core substance of the microcapsules, the water-soluble substance may be water or a water-soluble plant extract. , Water-soluble flame retardant, water-soluble organic substance, water-soluble inorganic substance, O / W (oil / aqueous solvent)
Examples include type emulsions, which may be used alone or in combination of two or more. In the aqueous solution [aqueous solution (B)] containing the water-soluble substance, the aqueous solution (B)
Includes cases where the whole is composed of water. To describe the water-soluble substance in more detail, the water-soluble plant extract, aroma, antibacterial, as having effects such as anti-mite, for example, bamboo dry distillation extract, aloe extract, mugwort extract, of the various plant essential oils described below. Examples thereof include emulsions. Examples of the water-soluble flame retardant include borate, ammonium sulfate, tetrakis / hydroxymethylphosphonium chloride / urea condensate, oligo (P-vinyl-P-oxo / 1.3 / dioxa-2-phosphapentylene). ,
Oligo (P-vinyl-P-oxo.1.3 dioxa-
2-phosphapentylene), phosphorous acid, polyalkylene polyamine / dicyandiamide ammonium salt condensate,
Examples thereof include potassium hexafluorozirconate and tetrabromophthalic anhydride. Examples of the water-soluble organic substance include sucrose, glucose, starch, carboxymethyl cellulose, malic acid, citric acid and the like. As the water-soluble inorganic substance, when a microcapsule dispersion is used as a cold storage material or a cold insulation material, for example, calcium chloride hexahydrate, sodium sulfate decahydrate, sodium hydrogen phosphate decahydrate, thiosulfate Sodium pentahydrate,
Examples thereof include inorganic hydrates containing a large amount of crystal water such as nickel sulfate and hexahydrate. In the above-mentioned O / W type (oil / water type) emulsion, the oil constituents include hinoki oil, tea tree oil, anise oil, cassia oil, bay oil, cinnamon bark oil, perilla oil, hiba oil, allyl isothiocyanate, cedar oil. , Moon peach oil, citrus oil,
Ginger oil, bouquet, rose oil, green floral, eucalyptus oil, lavender oil, jasmine,
Examples thereof include lemon oil, various plant essential oils such as various herbs, oil-based flame retardants (HBCD) such as hexabromocyclododecane, and natural and synthetic flavors. Examples of water constituents include water, water-soluble plant extracts, water-soluble flame retardants, water-soluble organic substances, water-soluble inorganic substances and other water-soluble substances. The concentration of the water-soluble substance is preferably 70% or less of the total amount of the aqueous solution (B).

Next, when emulsifying and dispersing a mixed aqueous solution obtained by mixing the aqueous solution containing the aminoplast resin initial condensate [aqueous solution (A)] and the aqueous solution containing a water-soluble substance [aqueous solution (B)], In the dispersant-containing hydrophobic solvent used, the hydrophobic solvent is 30 to 200.
It is preferable to use an aliphatic hydrocarbon having a boiling point of 0 ° C. or an alicyclic hydrocarbon having the above boiling point in consideration of the subsequent reaction / production steps. In particular, the boiling point is 30 to 10 from the viewpoint of economic efficiency in the above reaction and manufacturing process.
It is preferably 0 ° C., and specific examples thereof include n-hexane, cyclohexane, pentane, heptane, isopentane, isohexane, pentene, hexene, heptene, acetone, ethyl methyl ketone and the like. Among them, it is particularly preferable to use n-hexane or cyclohexane from the viewpoints of economy and emulsion stability.

As the dispersant contained in the above hydrophobic solvent, one having a good dispersibility is used.
Each compound described below having 3 to 15 is mentioned.
That is, HLBs such as sorbitan sesquioleate, sorbitan monostearate, and sorbitan monolaurate
Polyoxyalkylene sorbitan fatty acid ester having 3 to 15 HLB such as sorbitan fatty acid ester having 3 to 15, sorbitan sesquioleate, sorbitan monostearate, sorbitan monolaurate, polyoxyalkylene monononyl phenyl ether, polyoxyalkylene mono HLB3-1 such as lauryl ether
Examples thereof include polyoxyalkylene monoether type nonionic surfactants having 5 and polyoxyalkylene monoester type nonionic surfactants having HLB 3 to 15 such as polyoxyalkylene monooleate. Used in combination of two or more. Furthermore, the structure of the compound may be random, block or any structure.

Next, a method for producing a microcapsule dispersion liquid (W / O type microcapsule dispersion liquid) in which microcapsules are dispersed in a hydrophobic medium in the present invention using the above various materials (first manufacturing step) I will describe.

First, as described above, an aqueous solution containing the aminoplast resin precondensate [aqueous solution (A)] is prepared, and this aqueous solution (A) and an aqueous solution containing a water-soluble substance [aqueous solution (B)] are prepared. ] And are mixed to prepare a mixed aqueous solution.
The amount of the aqueous solution (A) added during this mixing is 5 to the total amount of the aqueous solution (B) and the aqueous solution (A).
It is preferably set in the range of 70% by weight (hereinafter abbreviated as “%”), and more preferably 40 to 60%. That is, when the amount of the aqueous solution (A) added is less than 5%, the strength of the obtained microcapsules is insufficient, and conversely 70%.
If it exceeds, the ratio of the aqueous solution (B) as the core substance decreases, and it becomes difficult to achieve the intended purpose of the microcapsules. In the preparation of this mixed aqueous solution, when the entire aqueous solution (B) is composed of water, the composition of the aminoplast is the same as that of only the aqueous solution (A) produced by the production of the above aqueous solution (A). In addition to adjusting the concentration of the resin initial condensate, water [aqueous solution (B)]
Is not necessary, and the mixed aqueous solution is composed of only the aqueous solution (A). Then, before mixing and emulsifying the mixed solution with a dispersant-containing hydrophobic solvent described below,
It is preferable to previously adjust the pH of the mixed solution to a pH range of 2 to 7. That is, by adjusting the pH within such a range, the film forming reaction due to the polycondensation of the aminoplast resin initial condensate can efficiently proceed (catalytic effect). This pH adjustment is performed by adjusting the pH to 2 as described above.
It is adjusted to the acidic side of ~ 7, preferably in the range of pH 3-6. Various organic acids, mineral acids and the like are used for this pH adjustment, and specific examples thereof include citric acid and the like.

On the other hand, the above mixed aqueous solution is emulsified and dispersed,
A hydrophobic solvent containing a dispersant is prepared. The amount of the dispersant added to the hydrophobic solvent is 0.1 to the hydrophobic solvent.
It is preferably set in the range of 20.0%, more preferably 1.0 to 5.0%. That is, when the amount of the dispersant added is less than 0.1%, the emulsifying power is insufficient, and as a result,
It becomes difficult to obtain a good spherical microcapsule, and if it exceeds 20.0%, the capsule particles may stick to each other when the microcapsule is dried. In addition, foaming occurs during desolvation when producing a W / W type microcapsule dispersion (through a second production step) using the W / O type microcapsule dispersion obtained through the first production step. Easy to manufacture and difficult to manufacture.

Then, the mixed aqueous solution is emulsified and dispersed in the hydrophobic solvent in the presence of a dispersant. After emulsifying and dispersing, the whole system in which the mixed aqueous solution is emulsified and dispersed is heated and stirred, and the aminoplast resin initial condensate in the aqueous solution (A) is subjected to polycondensation reaction (in situ polymerization) to form an aminoplast resin film. To form microcapsules containing the aqueous solution (B). The heating conditions in the polycondensation reaction are specifically 50
The temperature is set in the range of ℃ to the boiling point of the hydrophobic solvent. By passing through such a manufacturing process, a microcapsule dispersion liquid (W / O type microcapsule dispersion liquid) in which the above-mentioned microcapsules are dispersed in a hydrophobic medium is manufactured.

Next, a microcapsule dispersion liquid (W / W microcapsule) in which microcapsules are dispersed in an aqueous medium, using the W / O type microcapsule dispersion liquid obtained through the first manufacturing step, The manufacturing method (second manufacturing step) of the dispersion) will be described.

The W / O type microcapsule dispersion obtained through the first production step is mixed with water or an aqueous solution (D) containing a surfactant or a water-soluble polymer compound and emulsified. Then, the hydrophobic solvent is removed from the system to produce a microcapsule dispersion liquid (W / W type microcapsule dispersion liquid) in which the above-mentioned microcapsules are dispersed in an aqueous solvent. The surfactant in the aqueous solution (D) is not particularly limited, and various conventionally known surfactants, for example, polyoxyalkylene sorbitan fatty acid ester having HLB of 9 or more, polyoxyalkylene monoether type nonionic surfactant, poly Examples thereof include oxyalkylene monoester type nonionic activators, sodium naphthalenesulfonate-formalin condensates, and sulfuric acid esters of higher alcohols. Examples of the water-soluble polymer compound include polyvinyl alcohol, gum arabic, sodium alginate, styrene sulfonic acid type polymer, maleic anhydride type copolymer, carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, xanthan gum and the like. The mixing ratio of the W / O type microcapsule dispersion liquid and the aqueous solution (D) containing water or a surfactant or a water-soluble polymer compound is a weight ratio of W / O type microcapsule dispersion liquid: aqueous solution ( D) = 5: 95 to 80:20 is preferably set, and in particular, W / O type microcapsule dispersion liquid: aqueous solution (D) from the viewpoint of ease of production and increase in active ingredient content. = 40: 60 to 70:30 is more preferable.

The microcapsule contents of the W / O type microcapsule dispersion liquid and the W / W type microcapsule dispersion liquid obtained as described above are appropriately set according to their applications. Generally, 20-70 in the dispersion
% Range. And each said dispersion liquid is used suitably according to each use. For example, the above W
Examples of the use of the / O type microcapsule dispersion liquid include various oil-based materials (for paints, inks, cosmetics, lubricants, flame retardants, etc.). In addition, the W / W type microcapsule dispersion liquid can be used as a cold storage material (for refrigerators, cold storage materials, etc.), various water-based materials (for paints, inks,
Cosmetics, lubricants, flame retardants, etc.).

When the W / W type microcapsule dispersion liquid is used as the regenerator material in the above applications, the higher the proportion of the microcapsules dispersed in the regenerator material, the more the latent heat amount increases, which is preferable. However, considering that good fluidity is maintained, the amount of dispersed microcapsules is 2
It is preferably set to 0 to 70%, more preferably 40 to 60%. That is, if the microcapsule dispersion amount is less than 20%, the cold storage effect becomes poor, and if it exceeds 70%, the viscosity of the cold storage material itself increases, and the fluidity decreases accordingly.

The above W / O type microcapsule dispersion, W
For each / W type microcapsule dispersion liquid, the method for extracting the microcapsules from each dispersion liquid is as follows:
For example, regarding the W / O type microcapsule dispersion,
Examples of the method include removing the hydrophobic solvent by centrifugation, pressure filtration, vacuum suction filtration, or the like. For the W / W type microcapsule dispersion, centrifugation, pressure filtration,
A method of taking out the microcapsules using a vacuum suction filtration method or the like can be mentioned. Then, the microcapsules thus taken out may be appropriately dried by a conventionally known method, for example, heat drying, spray drying, vacuum drying, freeze drying and the like.

The particle size of the microcapsules thus produced is not particularly limited, but is generally set in the range of 0.1 to 50 μm.

Next, examples will be described.

[0034]

Example 1 A W / O type microcapsule dispersion was prepared as follows. [Aminoplast resin initial condensate] 50 parts by weight of melamine resin powder (hereinafter abbreviated as "part"),
The pH was adjusted to 8.5 by adding 65 parts of 37% formaldehyde aqueous solution (formalin) and 100 parts of water (core substance). Then, the mixture was heated to about 70 ° C. to produce an aqueous solution of melamine-formaldehyde resin initial condensate.

[Suspension / Emulsion Dispersion Step] Next, 90 parts of an aqueous melamine-formaldehyde resin initial condensate solution having a pH adjusted to 4.0 with citric acid was dissolved in sorbitan monolaurate to a concentration of 5%. It was added to 110 parts of n-hexane prepared above with vigorous stirring, and emulsified and dispersed until the particle diameter became 10 μm.

[Microencapsulation Step] By continuously stirring the dispersion liquid at 60 ° C. for 8 hours, the melamine-formaldehyde resin initial condensation product is subjected to a polycondensation reaction (in-situ polymerization), and a film formed by the condensation product is formed. By forming it, a microcapsule dispersion liquid (W / O type microcapsule dispersion liquid) containing water (core substance) was manufactured. The particle size of the obtained microcapsules was about 10 μm as a result of measurement by an electron microscope.

[0037]

[Examples 2 to 4] [Suspension
In the emulsification dispersion step], 40 parts of the water-soluble substance shown in Table 1 below was added to 50 parts of the aqueous solution of the initial condensate of melamine-formaldehyde resin whose pH was adjusted to 3.0 by adding citric acid. 90 parts of resin initial condensate aqueous solution was used. Other than the above, the same manufacturing process as in Example 1 was performed to manufacture a microcapsule dispersion liquid (W / O type microcapsule dispersion liquid) containing the above core substances. The particle diameters of the obtained microcapsules were all about 10 μm as a result of measurement by an electron microscope.

[0038]

[Table 1]

[0039]

Example 5 The pH was adjusted to 3.0 by adding citric acid,
4.5 parts of melamine-formaldehyde resin initial condensate prepared in the manufacturing process of Example 1, and 50% of aloe extract
90 parts total melamine mixed with 85.5 parts aqueous solution
A formaldehyde resin initial condensate aqueous solution was used. Other than the above, the same production process as in Example 1 was performed to produce a microcapsule dispersion liquid (W / O type microcapsule dispersion liquid) containing an aloe extract. The particle size of each of the obtained microcapsules was measured by an electron microscope and found to be about 7 μm.
m.

[0040]

Example 6 The pH was adjusted to 3.0 by adding citric acid,
A total of 90 parts of the melamine-formaldehyde resin initial condensate aqueous solution prepared by mixing 63 parts of the melamine-formaldehyde resin initial condensate prepared in the production process of Example 1 and 27 parts of an aloe extract 50% aqueous solution was used. Other than the above, the same production process as in Example 1 was performed to produce a microcapsule dispersion liquid (W / O type microcapsule dispersion liquid) containing an aloe extract. The particle size of the obtained microcapsules was about 5 μm as a result of measurement by an electron microscope.

[0041]

[Comparative example] 70 ml of 100 ml of sodium acetate trihydrate
After heating to 0 ° C. to completely melt the mixture, ethylenediamine (0.3 mol / liter) and sodium carbonate (0.6 mol / liter) were added thereto, and the mixture was stirred and mixed.

On the other hand, to 1 liter of a mixed solvent of cyclohexane and carbon tetrachloride in a weight ratio of 1: 3.3 (adjusted to have the same specific gravity as the specific gravity of sodium acetate trihydrate melt 1.30) is added. After adding 0.9 mol of sebacic acid dichloride and 0.09 mol of trimesic acid trichloride,
It was heated and kept at 70 ° C. Add the above sodium acetate
When the mixture melt of trihydrate was dropped, microcapsules were formed, and microcapsules (particle diameter 3.6 mm, film thickness 0.05 mm) were dispersed in the above mixed solvent to prepare a microcapsule dispersion liquid.

From each microcapsule dispersion liquid (W / O type microcapsule dispersion liquid) thus obtained, microcapsule particles were taken out by centrifugation, and the strength of the microcapsules themselves was measured by the following method. The results are shown in Table 2 below. The strength of the above-mentioned microcapsules was obtained by applying a W / O type microcapsule dispersion liquid to a test cloth (a polyester / cotton mixed spinning cloth) and squeezing it with a mangle of 8 kg / cm ² . Then, the test cloth was observed with an electron microscope to confirm whether or not the applied microcapsules were broken.

[0044]

[Table 2]

From the results shown in Table 2 above, all Example products
It can be seen that the microcapsule strength is superior to that of the comparative example product.

Next, a microcapsule dispersion liquid (W / W type microcapsule dispersion liquid) in which microcapsules are dispersed in an aqueous medium will be described.

[0047]

Examples 7 to 12 Example 1 obtained as described above
Each of the above microcapsule dispersions (W / O type microcapsules) was vigorously stirred while 55 parts of 10% polyvinyl alcohol aqueous solution (D) was used. Dispersion)
100 parts were mixed. Then, by heating the entire system to 80 ° C. and removing (desolventizing) n-hexane from the system,
A W / W type microcapsule dispersion was manufactured.

From each microcapsule dispersion thus obtained (W / W type microcapsule dispersion), microcapsule particles were taken out by centrifugation and the strength of the microcapsules themselves was measured by the same method as described above. did. The results are shown in Table 3 below.

[0049]

[Table 3]

From the results shown in Table 3 above, all the products of Examples were
It can be seen that the microcapsule strength is excellent.

[0051]

INDUSTRIAL APPLICABILITY As described above, the present invention uses an aminoplast resin initial condensate and prepares a mixed aqueous solution of this aqueous solution and an aqueous solution containing a water-soluble substance as a core substance with a hydrophobic agent containing a dispersant. By emulsifying and dispersing in a solvent and heating and stirring this system to cause a polycondensation reaction of the aminoplast resin initial condensate, a dispersion liquid of microcapsules in which the core substance is included in the aminoplast resin coating film is produced. It is a thing. The microcapsules of the microcapsule dispersion liquid thus produced are excellent in strength.

Particularly, the hydrophobic solvent has a boiling point of 30 to 30.
By using an aliphatic hydrocarbon or an alicyclic hydrocarbon at 200 ° C., it becomes easy to dry the microcapsules and to produce the water-soluble solvent microcapsule dispersion from the hydrophobic solvent microcapsule dispersion. . Also,
As the dispersant, each dispersant having HLB 3 to 15 shown below, sorbitan fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, polyoxyalkylene monoether type nonionic surfactant, polyoxyalkylene monoester type nonionic interface It is preferable to use an activator from the viewpoint of its dispersibility.

Further, the microcapsule dispersion obtained by the above-mentioned method for producing a microcapsule dispersion is mixed with water or an aqueous solution (D) containing a surfactant or a water-soluble polymer compound and emulsified. By removing the hydrophobic solvent, a microcapsule dispersion liquid in which microcapsules are dispersed in an aqueous solvent can be easily produced.

The thus obtained microcapsule dispersion liquid in which microcapsules are dispersed in the above-mentioned hydrophobic solvent and microcapsule dispersion liquid in which microcapsules are dispersed in an aqueous solvent are substances contained in the microcapsules. It is used in various fields depending on the (core substance).

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Claims (7)

[Claims] 1. A step of producing the following aqueous solution (A):
Mixing the aqueous solution (A) with the following aqueous solution (B) to prepare a mixed aqueous solution; emulsifying and dispersing the mixed aqueous solution in the presence of a dispersant in a hydrophobic solvent; The emulsion-dispersed system is heated and stirred to cause polycondensation reaction of the aminoplast resin initial condensate in the aqueous solution (A) to form an aminoplast resin coating film, thereby forming microcapsules containing the aqueous solution (B). A method for producing a microcapsule dispersion, comprising: a step of producing. (A) An aqueous solution containing an aminoplast resin initial condensate. (B) An aqueous solution containing a water-soluble substance. 2. The microcapsule dispersion according to claim 1, wherein the hydrophobic solvent is at least one of an aliphatic hydrocarbon having the following characteristic (C) and an alicyclic hydrocarbon having the following characteristic (C). Manufacturing method. (C) Boiling point is 30 to 200 ° C. 3. The method for producing a microcapsule dispersion according to claim 1, wherein the dispersant is a dispersant (a) having HLB 3 to 15 shown below. (A) at least one dispersant selected from the group consisting of sorbitan fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, polyoxyalkylene monoether type nonionic surfactant and polyoxyalkylene monoester type nonionic surfactant . 4. The water-soluble substance in the aqueous solution (B) is selected from the group consisting of water, a water-soluble plant extract, a water-soluble flame retardant, a water-soluble organic substance, a water-soluble inorganic substance, and an oil / water emulsion. The method for producing the microcapsule dispersion according to any one of claims 1 to 3, which is at least one. 5. In addition to the method for producing the microcapsule dispersion according to any one of claims 1 to 4, further, microcapsules are taken out from the microcapsule dispersion obtained by the above-mentioned production method. The method of making microcapsules. 6. A microcapsule dispersion obtained by the method for producing a microcapsule dispersion according to claim 1, after being mixed with water or the following aqueous solution (D) to be emulsified, A process for producing a microcapsule dispersion, which comprises removing the hydrophobic solvent and dispersing the microcapsules in an aqueous solvent. (D) An aqueous solution containing a surfactant or a water-soluble polymer compound. 7. A method for producing a microcapsule, characterized in that, in addition to the method for producing a microcapsule dispersion according to claim 6, the microcapsule is taken out from the microcapsule dispersion obtained by the above-mentioned production method.