JPH06362A - Production of microcapsules - Google Patents

Abstract

PURPOSE:To produce at high yield and industrially advantageously tageously a large microcapsules contg. hydrophobic liquid as a core material by using an interfacial polymerization reaction. CONSTITUTION:In a production of microcapsules in which hydrophobic liquid is covered with polyurethane or polyurethane resin by the interfacial polymn. reaction, the hydrophobic liquid formed by being dissolved with a polybasic halide and a polyvalent isocianate is added to an aq. solution of a water soluble high molecular material having OH group, NH2 group or NH group and is dispersed and then, after alkali compd. is added, a polyvalent amine or polyhydric alcohol is added.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing microcapsules in which a hydrophobic liquid such as a fragrance, an insecticide or a fertilizer is coated with polyurea or a polyurethane resin as a core substance by an interfacial polymerization reaction.

[0002]

2. Description of the Related Art Conventionally, as an encapsulation method for forming a synthetic polymer wall film of polyurea, polyurethane or the like at the interface using a hydrophobic liquid as a core substance, for example, Japanese Patent Publication No. 42-7.
No. 71 discloses a method of obtaining a capsule having a polyurea wall film by reacting a polyvalent isocyanate with water or amines. In addition, Japanese Patent Publication No. 47-13740
Japanese Patent Publication No. 52-13508, Japanese Patent Laid-Open No. 62-
No. 193641 discloses that a polyurea resin is produced by an interfacial polymerization reaction in which a hydrophobic liquid in which a polyisocyanate is dissolved is added and dispersed in an emulsion stabilizer-containing aqueous solution such as polyvinyl alcohol, and then a polyvalent amine is added. A method for obtaining microcapsules by the above is described.

According to these methods, microcapsules having a single coating of a hydrophobic liquid with a resin such as polyurea or polyurethane can be obtained. Microcapsules having a particle size of 50 to 100 μm can be produced, but microcapsules can be produced. When the particle size of the capsule is 150 μm or more, the film strength decreases,
There is a problem that the capsule membrane is destroyed by stirring during the reaction.

[0004]

[Problems to be Solved by the Invention]
By increasing the particle size, the entire surface is reduced, the sustained release property is improved, and it has the advantage that it can be identified with the naked eye. Development of effective manufacturing methods is required.

The present invention has been made in order to meet the above-mentioned demand, and provides a method for producing microcapsules capable of producing a high yield of microcapsules containing a hydrophobic liquid as a core substance and having a large particle size by interfacial polymerization. The purpose is to do.

[0006]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have manufactured microcapsules in which a hydrophobic liquid is coated with a resin such as polyurea or polyurethane by an interfacial polymerization reaction. In the method, a hydrophobic liquid obtained by dissolving a polybasic acid halide and a polyvalent isocyanate is added to and dispersed in an aqueous solution of a water-soluble polymer substance having an OH group, an NH ₂ group or an NH group, and then an alkaline compound is added. It was found that microcapsules with a large particle size containing a hydrophobic liquid as a core substance can be produced in high yield and industrially advantageously by adding polyvalent amine or polyhydric alcohol after adding did.

[0007]

A hydrophobic liquid obtained by dissolving a polybasic acid halide and a polyisocyanate is added and dispersed in an aqueous solution of a water-soluble polymer substance having an OH group, an NH ₂ group or an NH group, and an alkaline compound is further added. Is added, the alkaline compound acts as a catalyst, and the water-soluble polymer substance is partially crosslinked by the polybasic acid halide at the interface between the hydrophobic liquid and the aqueous phase to form a porous thin film. Further, when a polyvalent amine or a polyhydric alcohol is added thereto, a polyurea or polyurethane wall film is formed by a polymerization reaction of the polyvalent isocyanate and the polyvalent amine or the polyhydric alcohol to obtain microcapsules.

Thus, polybasic acid halide, OH group, N
After the reaction with the water-soluble polymer having H ₂ group or NH group proceeds, the reaction between polyvalent isocyanate and polyvalent amine or polyhydric alcohol occurs, and the microcapsule film forms a double film structure. The film strength is improved, and the capsule film is not broken even if the capsule particle size is 150 μm or more.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, first, a hydrophobic substance obtained by dissolving a polybasic acid halide and a polyisocyanate is dissolved in an aqueous solution of a water-soluble polymer substance having an OH group, an NH ₂ group or an NH group. Disperse into

Here, the hydrophobic liquid is a core substance of the microcapsules, and is selected variously according to the use of the microcapsules. For example, esters, alcohols, aldehydes, ketones, hydrocarbons, etc. One kind or two or more kinds of can be used. In particular, in the production method of the present invention, since it is possible to produce microcapsules with a high yield even when alcohols are contained in the hydrophobic liquid, hexanol, cis-3-hexanol, linalool, geraniol as a hydrophobic substance, Citronellol, α
-Slightly water-soluble or insoluble alcohols such as terpineol, 1-menthol, borneol, benzyl alcohol and β-phenylethyl alcohol can be effectively used. These hydrophobic liquids may be used as they are, or may be used by impregnating a solid substance.

Examples of polybasic acid halides to be dissolved in the hydrophobic liquid include terephthaloyl chloride, adipoyl chloride, sebacyl chloride, isophthaloyl chloride, 4,4'-biphenyldicarbonyl chloride, and , 10-decanedicarbonyl chloride, dodecanediacid chloride, benzenetetraacid chloride, trimesoyltrichloride and the like. These polybasic acid halides may be used alone or in combination.
Combinations of more than one species can be used.

The amount of the polybasic acid halide used is not particularly limited, but the concentration of the polybasic acid halide in the hydrophobic liquid is 0.
It is preferable to dissolve it so as to be from 01 to 2.5 mol / liter.

Further, as the polyisocyanate to be dissolved in the hydrophobic liquid together with the above polybasic acid halide, hexamethylene diisocyanate, toluylene diisocyanate, diphenylmethane diisocyanate, m-xylylene diisocyanate, m-phenylene diisocyanate, trimethylhexamethylene diisocyanate, Diisocyanates or diisothiocyanates such as isophorone diisocyanate, xylylene-1,4-diisothiocyanate, and ethylidyne diisothiocyanate; triisocyanates such as triphenylmethane isocyanate, octylsilane triisocyanate; Desmodur L, T, N, E, Products commercially available from Bayer under the trade names Z, R, M, etc., and polyvalent amines, polyvalent carboxylic acids, and polyvalent thiols. , Polyhydroxy compounds, such as polyvalent isocyanate to epoxy compounds are added.

The amount of the polyvalent isocyanate used is not particularly limited, but it is preferable to dissolve the polyvalent isocyanate so that the concentration of the polyvalent isocyanate in the hydrophobic liquid is 0.05 to 10.0 mol / liter. These polyisocyanates have 1
The seeds may be used alone or in combination of two or more.

OH group, NH ₂ to which the above hydrophobic liquid is added
Examples of the water-soluble polymer substance having a group and an NH group include the following. Examples of natural macromolecules include pullulan, xanthan gum, curdlan, dextrin, succinoglucan, schizophyllan, nigeran, levan, rutinic acid, mannan, basidiomycete polysaccharides, and other microbial macromolecules, guar gum, locust bean gum, tamarind gum. , Seed polysaccharides such as tara gum, pectin, fruit polysaccharides such as quince seed gum, starch, rhizome polysaccharides such as dextrin, gum arabic, arabic galactan, tragacanth gum, karaya gum, resin gums such as gum tea gum, carrageenan, alginic acid, agar , Seaweed polysaccharides such as furceleran, animal-based polymers such as gelatin, casein, albumin and chitosan.

Examples of the semi-synthetic polymer include carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, hydroxypropyl methyl cellulose phthalate, cationized cellulose, cellulose sulfate, starch derivative and guar gum derivative.

Examples of synthetic polymers include polyvinyl alcohol, polyacrylamide, water-soluble nylon, polyethylene glycol and the like. These water-soluble polymers can be used alone or in combination of two or more. Of these, polyvinyl alcohol and gelatin are particularly preferable.

The concentration of the above water-soluble polymer having OH group, NH ₂ group and NH group in water is not particularly limited,
0.01-5% (wt%, the same applies below), especially 0.1-3
% Is preferable. If the concentration of the water-soluble polymer is out of the above range, the microcapsule yield may decrease. Furthermore, the addition amount of the hydrophobic liquid in which the polybasic acid halide and the polyisocyanate are dissolved into the water-soluble polymer-containing water is 10 to 100% with respect to the water-soluble polymer-containing aqueous solution.
It is preferable that

Next, in the production method of the present invention, microcapsules are obtained by adding an alkaline compound to a water-soluble polymer aqueous solution in which a hydrophobic liquid is dispersed, and then adding a polyvalent amine or a polyhydric alcohol. .

In the present invention, after the alkaline compound is added as described above, the polyvalent amine or the polyhydric alcohol is added to the aqueous solution of the water-soluble polymer, so that the alkaline compound first acts as a catalyst and becomes water-soluble at the interface. When a polymer is partially cross-linked with a polybasic acid halide to form a porous thin film, and then a polyvalent amine or polyhydric alcohol is added, the polyvalent isocyanate and the polyvalent amine or polyhydric alcohol are polymerized to react. A double wall structure is formed to form a polyurea or polyurethane wall film having high film strength.

In this case, as the alkaline compound, an alkali or a salt of an alkali and a weak acid can be used. Specifically, NaOH, KOH, Ca (OH) ₂ , Na ₂ CO ₃ ,
(NH ₄ ) ₂ CO ₃ , sodium silicate, sodium phosphate and the like are preferable. The addition amount of the alkaline compound is appropriately selected, but it is preferably 5 to 100% of the neutralization equivalent of the acid generated by the crosslinking reaction between the water-soluble polymer and the polyvalent halide.

Further, when adding the alkaline compound,
The reaction conditions are not particularly limited, but the reaction temperature is preferably 0.
The reaction proceeds easily by stirring at -60 ° C for 1-60 minutes.

As the polyvalent amine, hexamethylenediamine, m-xylylenediamine, ethylenediamine, 1,
Diamines such as 4-diaminobutane, p-phenylenediamine, lysine, piperazine, dibasic amino acids, modified polyamines such as amine adducts of epoxy resins, trivalents such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine. The above amines and the like can be mentioned.

Polyhydric alcohols include polyether glycols such as ethylene glycol, butanediol, hexanediol, xylylene glycol, polyoxypropylene glycol, glycerin and pentaerythritol, polyester polyols such as ethylene adipate and acrylic esterol, acrylic polyols, Polybutanediene polyol, polyolefin-based polyol, saponified EVA (ethylene-vinyl acetate copolymer), etc., whose main chain is a C—C bond, phosphorus-containing polyol,
Examples of the flame-retardant polyol include halogen-containing polyols, aromatic amine-based polyols, phenol-based polyols, aromatic polyesters and the like.

These polyvalent amines or polyhydric alcohols can be used alone or in combination of two or more. The addition amount of the above polyvalent amine or polyhydric alcohol is 10 equivalent to the reaction equivalent of the polyvalent isocyanate.
It is preferably set to ˜1000%.

The reaction conditions for adding the polyvalent amine or the polyhydric alcohol are not particularly limited, but the reaction temperature is preferably 0 to 80 ° C. and the polymerization reaction is efficiently performed by stirring for about 1 to 6 hours. move on.

[0027]

As described above, according to the method for producing microcapsules of the present invention, microcapsules containing a hydrophobic liquid as a core substance by utilizing an interfacial polymerization reaction are produced in high yield and industrially. In particular, by improving the strength of the capsule film, it is possible to manufacture a capsule having a large particle size (for example, 150 μm or more), and the capsule film has a dense structure.

Further, the microcapsules obtained by the production method of the present invention have a sustained release property because the core substance is coated with a porous thin film, and the core substance is gradually released. It can be used as a fragrance product such as an aromatic agent by encapsulating as a core substance, or by encapsulating an insecticidal ingredient, an attractant, a repellent, a fungicide, a herbicide, etc. as a core substance and using it as an agricultural chemical or an insecticide. it can.

[0029]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited to the following examples.

Example 1 Ethyl butyrate 10%, ethyl caproate 10%,
After dissolving 2.3 g of terephthaloyl chloride and 20 g of hexamethylene diisocyanate in 150 g of a fragrance composition containing 10% of 1-hexanol, 5% of amyl acetate and 65% of linalool, the fragrance composition was treated with polyvinyl alcohol (polymerization degree: 500). , Saponification degree 88%) 7.5
It was dispersed in 750 g of an aqueous solution containing g under stirring to adjust the average particle size to 300 μm.

Then, 46 g of a 2% aqueous sodium hydroxide solution was added to the dispersion solution of the fragrance composition at a reaction temperature of 20 ° C. and the mixture was stirred for 10 minutes, and terephthaloyl was added to polyvinyl alcohol at the interface between the fragrance composition and the aqueous phase. A porous thin film crosslinked with chloride was formed. The presence of this thin film was confirmed by an optical microscope.

Further, 14 g of hexamethylenediamine was added to this dispersion and stirred for 2 hours to promote the polymerization reaction of hexamethylenediisocyanate and hexamethylenediamine at the interface between the fragrance composition and the aqueous phase to form a polyurea wall film. The obtained microcapsules were obtained.

The average particle size of this microcapsule is 300.
In μm, its presence could be confirmed with the naked eye. Further, when the microcapsule dispersion was observed with an optical microscope, it was confirmed that the uncoated fragrance composition particles were not present and the encapsulation yield was 100%. The obtained microcapsules emitted a floral scent and could be used as a fragrance.

Example 2 The procedure of Example 1 was repeated except that 20 g of hexamethylene diisocyanate and 20 g of hexamethylene diamine were replaced by 20 g of toluylene diisocyanate and 16 g of m-xylylene diamine. The average particle size was 300 μm, and its presence could be visually confirmed. The encapsulation yield is 100.
% Was confirmed. The microcapsules emitted a floral scent and could be used as a fragrance.

Example 3 Polyvinyl alcohol (polymerization degree: 500, saponification degree: 88)
%) Instead of gelatin (average molecular weight 3 × 10 ⁴ to 1)
0 ⁵ ), except that 7.5 g was used, the same operation as in Example 1 was carried out. The resulting microcapsules had an average particle size of 30.
At 0 μm, its presence could be visually confirmed. It was also confirmed that the encapsulation yield was 100%. The microcapsules emitted a floral scent and could be used as a fragrance.

Example 4 The same operation as in Example 1 was carried out except that 7 g of ethylene glycol was used instead of 14 g of hexamethylenediamine, to obtain microcapsules having a polyurethane wall film, and an average particle size of 300 μm. So, I was able to confirm its existence with the naked eye. It was also confirmed that the encapsulation yield was 100%. The microcapsules emitted a floral scent and could be used as a fragrance.

Comparative Example 1 When the same operation as in Example 1 was carried out without adding 2.3 g of terephthaloyl chloride and 46 g of 2% sodium hydroxide, formation of microcapsules was observed, but they were broken. In many cases, they were capsules, aggregated capsules, or both, and the encapsulation yield measured by an optical microscope was about 5%.

Comparative Example 2 Polyvinyl alcohol (polymerization degree: 500, saponification degree: 88)
%) Instead of polystyrene sulfonic acid sodium salt (average molecular weight 1.5 × 10 ⁴ ), the same operation as in Example 1 was carried out. No formation of microcapsules was observed. The measured encapsulation yield was about 0%.

Example 5 1-Hexanol 25%, Aldehyde C ₈ 5%, Aldehyde C ₉ 5%, Aldehyde C ₁₀ 5%, Linalool 10
%, Terephthaloyl chloride 1 g and toluylene diisocyanate 20 g were dissolved in a fragrance composition 150 g containing 50% of limonene, and then, in 750 g of an aqueous solution containing 7.5 g of polyvinyl alcohol (polymerization degree 500, saponification degree 88%). Dispersed under stirring with an average particle size of 300 μm
I adjusted it to be.

Next, 2 g of a 20% aqueous sodium carbonate solution was added to the dispersed aqueous solution of the fragrance composition at a reaction temperature of 20 ° C. and stirred for 30 minutes, and polyvinyl alcohol was added to terephthaloyl chloride at the interface between the fragrance composition and the aqueous phase. A cross-linked porous thin film was formed.

Further, ethylenediamine 7 was added to this dispersion.
g, and the mixture is stirred for 2 hours to advance the polymerization reaction of toluylene diisocyanate and ethylenediamine at the interface between the fragrance composition and the aqueous phase, to give a fragrance composition-encapsulating microcapsule (average particle size 300 μm) having a polyurea wall film. Obtained.

Observation of this microcapsule dispersion with an optical microscope showed that there were no broken capsules or uncoated particles, and the encapsulation yield was 100%. The obtained microcapsules emitted a citrus scent and could be used as an aromatic.

Example 6 Allethrin 90%, hexenol 5%, hexanal 5
After dissolving 1 g of sebacoyl chloride, 1 g of trimesoyl trichloride and 20 g of trimethylhexamethylene diisocyanate in 150 g of an insecticide composition containing 10%, polyvinyl alcohol (polymerization degree 1500,
The mixture was dispersed in 750 g of an aqueous solution containing 5 g of a saponification degree of 88%) under stirring to adjust the average particle size to 300 μm.

Then, the dispersion solution was added to the reaction solution at a reaction temperature of 10 ° C.
After adding 46 g of 2% aqueous sodium hydroxide solution and stirring for 20 minutes, 10 g of diethylenetriamine was added to 1
Stir for 0 minutes. Further, the reaction temperature was raised to 60 ° C. and the mixture was stirred to obtain microcapsules.

The obtained microcapsules contain an insecticide composition and have a polyurea wall film and an average particle size of 300 μm.
Microcapsules of 100% encapsulation yield
Met. The microcapsules could be used as an attractive insecticide.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Mototaka Kinoshita 1-3-7 Main Office, Sumida-ku, Tokyo Inside Lion Corporation

Claims (1)

[Claims] 1. A method for producing microcapsules in which a hydrophobic liquid is coated with polyurea or a polyurethane resin by an interfacial polymerization reaction, wherein the hydrophobic liquid obtained by dissolving a polybasic acid halide and a polyisocyanate is OH group, NH.
_A method for producing microcapsules, which comprises adding and dispersing in an aqueous solution of a water-soluble polymer having _two or NH groups, then adding an alkaline compound, and then adding a polyvalent amine or a polyhydric alcohol. .