JPH03182520A - Microcapsule of amine curing agent - Google Patents

Abstract

PURPOSE:To obtain an amine curing agent microcapsule excellent in storage stability, capable of low-temperature curing and useful as an epoxy resin curing agent by forming a core component from an amine curing agent having a specified water solubility and forming a wall component mainly from a radical- polymerized resin. CONSTITUTION:An amine curing agent microcapsule (of a mean particle diameter of 1-500mum, desirably 5-200mum) for curing an epoxy resin is formed from a core component (an amine curing agent having a water solubility <=10wt.%, e.g. 1-cyanoethyl-2-undecylimidazole desirably containing 10-1000 pts.wt. organic solvent per 100 pts.wt.) and a wall component (a polymer mainly consisting of a radical-polymerizable monomer, desirably a polymer comprising 0-90wt.%, especially 20-80wt.% nitrile monomer, 0-90wt.% (meth)acrylic monomer, 0-20wt.% vinyl monomer and 0-40wt.% crosslinking monomer).

Description

[Detailed description of the invention] Industrial applications The present invention relates to microcapsules of amine curing agents.

BACKGROUND OF THE INVENTION Epoxy resins are widely used for sealing, flooring, casting, laminating, adhesives, and coatings. This resin is obtained by mixing and reacting an epoxy compound (hereinafter simply referred to as prepolymer) with an amine curing agent.

Since the prepolymer and curing agent easily initiate a reaction upon contact, a two-component type is usually used and mixed immediately before use. Although the two-component type is preferable in terms of storage stability, it is troublesome as it requires mixing before use.

So-called - where prepolymer and curing agent are filled in the same container.
For molding, (1) a method using a component with a relatively high curing temperature such as boron fluoride, an amine complex, dicyandiamide, or an epoxy resin amine adduct as a curing agent; (2)
A method of adsorbing an amine curing agent to a molecular sieve, etc.; (3) A method of sealing the active group with a blocking agent, etc.;
4) Method of microencapsulating prepolymer; (5)
) A number of methods have been proposed, including methods for microencapsulating amine curing agents.

Methods (1) and (3) have good storage stability, but require high temperatures for curing; method (2) requires the use of a special release agent and is easily affected by humidity, etc. : Method (4) requires a large amount of capsule-forming agent, so only some methods, such as those using a diluent and a binder, have been put into practical use. Method (5) has conventionally employed exclusively interfacial polymerization. However, it has not been put into practical use due to insufficient capsule stability.

Problems to be Solved by the Invention The present invention provides a liquid-type composition for sealing, molding, casting, laminating, adhesion, or coating using an epoxy resin that has excellent storage stability and can be cured at low temperatures. The purpose of this study is to obtain microcapsules of amine curing agents useful as raw materials for products, etc.

Means for Solving the Problems The present invention provides a core component containing an amine curing agent having a solubility in water of 10% by weight or less, and a shell wall component containing a polymer whose main polymerization component is a radically polymerizable monomer. This invention relates to microcapsules of amine curing agents.

The amine curing agent to be microencapsulated in the present invention is not particularly limited as long as it has a solubility in water of 10% by weight or less among amine curing agents used for curing epoxy resins. If the amine curing agent has a solubility of 10% by weight or more, microencapsulation will not be successful due to its high solubility in water. Amine curing agents include, for example, primary, secondary or tertiary amines; monoamines, polyamines; aliphatic amines, aromatic amines, alicyclic amines, aliphatic amines, heterocyclic amines; special amines (e.g. ketimine); etc.), and typically, for example, the polyamine is a chain aliphatic polyamine, a cycloaliphatic polyamine, an aliphatic polyamine, an aromatic polyamine, specifically Laromin C-260 (BAS
F), mensendiamine (Rohm & Haas),
In7 Olondiamine, Wondermin HM (New Japan Chemical)
, diaminodiphenylmethane (Sumitomo Chemical), polyamide amines (Tomide (Fuji Kasei), Persamide (Henkel Hakusui), Laccamite (Dainippon Ink)); Alkylamines (tributylamine, dimethylhexylamine, dimethylcyclohexylamine, etc.), 2-(dimethylaminomethyl)
Phenol, 2.4.6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, tetramethylguanidine, linear diamine, etc.; Heterocyclic amines include 2-undecylimidazole, 2-heptadecylimidazole, 2-7 enyl imitasol, l-benzyl-2-methyl imitasol, l-
Examples include cyanoethyl-2-undecylimidazole.

The amine curing agent alone may be microencapsulated, but other suitable additives such as organic acids, solvents,
It may be used in combination with a plasticizer or the like.

The present invention is characterized in that a polymer containing a radically polymerizable monomer as a polymerization component is used as a shell wall component for microcapsulating these amine curing agents.

In the present invention, the reason why a radical polymer is used for microencapsulation is that microencapsulation is not inhibited by an amine curing agent and encapsulation is performed substantially completely, and that this microcapsule is blended into a prepolymer. The reason is that the microcapsule shell is not plasticized and can maintain stable microcapsules for a long period of time.

Examples of radically polymerizable monomers include nitrile monomers such as acrylonitrile, methacrylonitrile, β, β-
Dimethylacrylonitrile, crotononitrile, especially acrylonitrile and/or methacrylonitrile, etc.; amide monomers such as acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, crotonamide, maleic acid amide, itaconic acid amide , especially acrylamide and/or methacrylamide; (meth)acrylic monomers such as acrylic ester, methacrylic ester, ethyl acrylic ester,
Itaconic acid ester, maleic acid diester, crotonic acid ester or neutralized products of these acids, especially methacrylic acid ester; vinyl monomers such as vinyl acetate,
Styrene, vinyltoluene, methylstyrene, etc.; Crosslinkable monomers, such as divinylbenzene, ethylene di(
meth)acrylate, polyethylene di(meth)acrylate, N,N-methylenebis(meth)acrylamide,
Examples include triacrylic formal, polyvalent metal salts of (meth)acrylic acid (Mg, Ca5Zn, AI, etc.), and particularly divinylbenzene, ethylene diacrylate, methylene bisacrylamide, triacrylic formal, and the like.

These monomers may further partially contain other polymerizable monomers, such as vinyl chloride and vinylidene chloride.

Two or more of these monomers are usually used in combination in order to obtain desired properties. In particular, in addition to the monofunctional polymer, some polyfunctional (crosslinkable) monomers may be used for crosslinking to further suppress swelling in the prepolymer. Furthermore, a layer of microcapsules may be formed using another resin on the radical polymer shell.

The radically polymerizable monomers used in the present invention are 0 to 90% by weight of nitrile monomers and 0 to 25% by weight of amide monomers.
, (meth)acrylic monomer 0 to 90% by weight, vinyl monomer 0 to 20% by weight, and crosslinkable monomer 0 to 40% by weight.

Among the radically polymerizable monomers used in the present invention, particularly preferred monofunctional monomers include nitrile monomers such as acrylonitrile and methacrylonitrile as the main ingredient, and a small amount of difunctional monomers. It is a combination of the body.

The amount of nitrile monomer used in the monofunctional monomer is 0 to 9
It is preferably 0% by weight, more preferably 20 to 80% by weight, and the ratio of the monofunctional monomer to the polyfunctional monomer is preferably 100 parts by weight of the former and 0 to 50 parts by weight of the latter.

The amount of monomer used is 10% of the total components to be microencapsulated.
0 parts by weight, about 5 to 95 parts by weight, more preferably 20 parts by weight.
It is preferable to use up to 80 parts by weight.

The average particle size of the microcapsules is 1 to 500 μm, more preferably 5 to 200 μm.

The method for producing microcapsules is not limited, and various methods can be employed. Specifically, for example, an amine curing agent, a monomer, a catalyst, etc. are mixed in advance, or if desired, a solvent, a plasticizer, an organic acid, etc. are mixed, and this is mixed with a dispersant, a dispersion stabilizer, an electrolyte, etc. as desired. into an aqueous medium containing 1.000 to 10.0
After creating dispersed particles by stirring at about 0 Or, p, m, they are reacted. The reaction temperature is 90~150℃, the reaction pressure is 0゜1~10 kg/cm'', especially 0,5~5
ky/cva” is appropriate.

As a catalyst, an organic peroxide such as methyl ethyl ketone peroxide, cyclohexanone peroxide, 2.2
-bis(L-butylperoxy)valate, di-t-butylperoxide, dicumyl peroxide, octanoyl peroxide, benzoyl peroxide, etc.; azo compounds such as 2゜2-azobis(2,4-dimethyl valeronitrile), 2,2-azobis(2-methylbutyronitrile), 1,1-azobis(cyclohexyl-1-
carbonitrile), VA-061 (Wako Pure Chemical Industries), V
Examples include A-080, VR-110, and V-601.

The amount of catalyst used is 001-1 per 100 parts by weight of monomer.
0 parts by weight, more preferably 0.1 to 5 parts by weight.

The amine curing agent may be microencapsulated together with the solvent. Examples of such solvents include hydrocarbon compounds such as hexane, heptane, benzene, toluene, and xylene; halogenated hydrocarbons such as chloroform, carbon tetrachloride, trichlene, and trichloroethane; ethers such as diethyl ether, dipropyl ether, and dibutyl; Examples include esters such as ethyl acetate, propyl acetate, and butyl acetate.

The amount of solvent is 0 to 2 parts per 100 parts by weight of the amine curing agent.
．． 000 parts by weight, more preferably 10-1.000 parts by weight.

A solvent is used for the purpose of facilitating encapsulation when manufacturing microcapsules, facilitating elution of a hardening agent when breaking capsules, and the like.

Microencapsulation may be carried out in the presence of a plasticizer. The plasticizer not only acts as a diluent for the amine curing agent, but is also used to impart plasticity to the formed shell. Examples of such plasticizers include heptathalic acid esters such as dimethyl phthalate, dibutyl heptathalate, and dioctyl phthalate, phosphoric acid esters such as tributyl phosphate, triphenyl phosphate, and tricresyl phosphate, and butyl oleate. , aliphatic basic acid esters such as glycerin monooleate, aliphatic dibasic acid esters such as dibutyl adipate, 2-ethylhexyl adipate, and dibutyl sebacate, dihydric alcohol diesters such as diethylene glycol dibenzoate, acetyl ricinol Examples include oxyacid esters such as methyl acid and butylphthalylbutyl glycoate, chlorinated paraffin, chlorinated biphenyl, and alkylnaphthalene.

The amount of plasticizer used is 0 to 2.0 parts by weight per 100 parts by weight of the monomer.
000 parts by weight, more preferably 10-1.000 parts by weight.

In microencapsulation, organic acids such as benzoic acid, phthalic acid, organic carboxylic acids such as trimellitic acid; phenols such as phenol and cresol may also be used in combination. The amount of organic acid used is the amount necessary to neutralize part or all of the amine curing agent.

An electrolyte such as sodium chloride, potassium chloride, ammonium chloride, or magnesium chloride may be added to the aqueous medium for the purpose of suppressing the solubility of the amine curing agent or the polymerizable monomer in water.

The amount of these electrolytes used is 0-1 per 100 parts by weight of water.
00 parts by weight, more preferably 0 to 50 parts by weight.

A dispersant is added to the aqueous medium. Examples of the dispersant or dispersion stabilizer include water-soluble polymer compounds and water-insoluble inorganic fine powders.

Water-soluble polymer compounds include CMC, methylcellulose, PVA, hydroxypropylmethylcellulose, hydroxyethylpropylcellulose, etc., and inorganic fine powders include kaolin clay, calcined clay, sericite, talc, bentonite, organic bentonite, white carbon, and colloidal silica. , colloidal alumina, colloidal antimony, particulate silica, particulate alumina, particulate titanium, calcium carbonate, dolomite powder, calcium sulfate, barium sulfate, and the like.

The surface of the inorganic fine powder may be treated with a coupling agent such as a silane coupling agent to make it hydrophobic, or a coupling agent may be added to the polymerizable monomer or dispersion medium. Thereby, capsules with even better storage stability when made into a one-component type by mixing with a prepolymer can be obtained. The amount of the coupling agent used is 0 to 20 parts by weight, more preferably 0.01 to 10 parts by weight, per 100 parts by weight of the inorganic fine powder.
Parts by weight.

Coupling agents useful for surface treatment of inorganic fine powders include, for example, alkoxysilanes such as trimethylmethoxysilane, dimethyldimethoxysilane, methyltrimethoxysilane, tetramethoxysilane, trimethylethoxysilane, dimethyljethoxysilane, and dimethylvinylmethoxysilane. , methylvinyldimethoxysilane, diphenyldimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, γ-glycidoxyprobyl trimethoxysilane, γ-methacryloxypropyltrimethoxysilane, etc.; chlorosilane, such as trimethylchlorosilane, dimethyldichlorosilane, dimethylvinylsilane,
Methylchlorodisilane, methyldiphenylsilane, chloromethyldimethylchlorosilane, etc.; titanium coupling agents, such as isopropyl triisostearoyl titanate, inglovir trimethacryl titanate, isopropyl triacroyl titanate, isopropyl triacroyl titanate, isopropyl isostearoyl dimethacrylate Examples include titanate, inglobil tri(diine octyl phosphate) titanate, and isoprobil di(dodecylbenzenesulfonyl).

The amount of inorganic fine powder used is approximately 0.00 parts per 1001 parts of the aqueous medium.
1-100 parts by weight, more preferably 1-50 parts by weight are preferred.

The microcapsules of the present invention are incorporated into an epoxy compound (prepolymer) to be cured.

Epoxy resins include glycidyl ether of bisphenol A, glycidyl ether of bisphenol F, glycidyl ether of glycerin, glycidyl ether of polyalkylene oxide, glycidyl ether of phenol novolac, glycidyl ether of orthocresol novolak, glycidyl ether of brominated bisphenol A, etc. Glycidyl ether type epoxy resin, cycloaliphatic epoxy resin such as alicyclic gepoxy acetal, alicyclic gepoxy adipate, alicyclic gepoxy carboxylate, diglycidyl phthalate, diglycidyl tetrahydrophthalate Glycidyl ester resins such as ester, hexahydrodiglycidyl ester, dimer acid glycidyl diester, N,N-diglycidylaniline, tetraglycidylaminodiphenylmethane, triglycidyl-
Examples include glycidylamine resins such as p-aminophenol, heterocyclic epoxy resins, hydantoin type epoxy resins, and triglycidyl isocyanurate.

When blending the microcapsules of the present invention with an epoxy compound, other additives may be added depending on the intended use. For example, hardening agents such as acid anhydrides and polyamines, metal powders such as silver and molybdenum, inorganic fillers such as asbestos, alumina, kaolin clay, carbon black, fine powder silica, titanium oxide, boron nitride, and glass balloons, and glass. Fibers, fibers such as nylon and polyester, flexibility imparting agents such as monoepoxide, polyepoxide and polyol, organic fillers such as powdered polyethylene, powdered polystyrene and organic balloons, solvents, diluents such as monoepoxy compounds, pigments, Examples include coupling agents such as flame retardants, silane coupling agents, and titanium coupling agents.

The microcapsules can be used in powdered form by mixing with powdered epoxy resin or epoxy resin microcapsules. Epoxy resin microcapsules can be made, for example, by the method shown in U.S. Pat. No. 3,746,068. can do.

The microcapsules of the amine curing agent of the present invention are preferably blended in approximately stoichiometric amounts to the epoxy compound to be cured.

Liquid adhesives, sealants, paints, etc. containing the microcapsules of the present invention may be used by destroying the microcapsules by applying pressure or heating.

The present invention will be explained below with reference to Examples.

Example 1 Preparation of hydrophobic microcapsule material Curazole c, rz CN (t-cyanoethyl-2-undecylimidazole; manufactured by Shikoku Fine Chemical Co., Ltd.) 50 parts by weight, dioctyl phthalate 50 parts by weight, acrylonitrile 85 parts by weight, methacryl 10 parts by weight of methyl acid, 5 parts by weight of acrylamide, 0.5 parts by weight of methylenebisacrylamide and V-40 (1,1-
1 part by weight of azobis(cyclohexane-1-carbonitrile) manufactured by Wako Pure Chemical Industries, Ltd. was mixed.

Preparation of aqueous medium 400 parts by weight of water, 40 parts by weight of salt, and 20 parts by weight of Snowtex 20 (colloidal silica; manufactured by 0-San Kagaku Co., Ltd.) were mixed to prepare an aqueous medium.

Microencapsulation Mix the above microcapsule material and aqueous medium;
Using a homo mixer (manufactured by Tokushu Kika Kogyo Co., Ltd.),
The mixture was stirred and mixed for 2 minutes at 00 Orr, p-m, and further reacted at 110° C. for 5 hours with stirring in a sealed reaction vessel. After the reaction, the solution was filtered, washed with water, and dried to obtain 185 parts by weight of microcapsules with an average particle size of 20 pm.

Storage stability: 2 parts by weight of the microcapsules, 1 part of HN-2200 (methyltetrahydrophthalic anhydride; manufactured by Hitachi Chemical Co., Ltd.)
00 parts by weight and Epicote 828 (bisphenol A
A one-component type epoxy resin was prepared by mixing 80 parts by weight of a type epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd.).

This composition exhibited storage stability at 40°C for more than 30 days. Moreover, the bending strength of the molded product cured at 130° C. for 8 hours was l 3 , Okg/mra2.

Examples 2 to 6 Microcapsules were prepared in the same manner as in Example 1, except that the monomers were changed as shown in Table 1.

(Hereinafter, blank space) Example 7 Curesol Cr Z -CN was converted into Curesol IB
The reaction was carried out in the same manner as in Example 1 except that 2MZ (1-benzyl-2-methylimitasole; manufactured by Shikoku Fine Chemical Co., Ltd.) was used, and 180 parts by weight of microcapsules with an average particle size of 15 μm were obtained.

A composition obtained by mixing 2 parts by weight of the microcapsules, 100 parts by weight of HN-2200, and 80 parts by weight of Epicoat 828 exhibited storage stability at 40°C for 30 days or more. Further, the bending strength of the molded product cured at 130° C. for 8 hours was 12.8729/1ml”.

Example 8 A reaction was carried out in the same manner as in Example 1, except that 5 parts by weight of Aluminum Oxide C (alumina: manufactured by Nippon Aerosil Co., Ltd.) was used instead of 2020 parts by weight of Snowtex. As a result, 180 parts by weight of microcapsules with an average particle size of 30III were obtained. I got it.

Example 9 Except for changing Snowtex 2020 parts by weight to 4 parts by weight of Aerosil 200 (silica; manufactured by Nippon Aerosil Co., Ltd.) and 1 part by weight of Aerosil R812 (silica surface-treated with trimethylsilyl group; manufactured by Nippon Aerosil C Co., Ltd.).
When the reaction was carried out in the same manner as in Example 1, the average particle size was 50 μm.
170 parts by weight of heavy microcapsules were obtained.

Example 1O A reaction was carried out in the same manner as in Example 1 except that 0.1 part by weight of TSL8311 (vinyltriethoxysilane; manufactured by Toshiba Silicone Corporation) was added to the aqueous system. The average particle size was 28 μm.
180 parts by weight of microcapsules were obtained.

Comparative Example A mixture of a solution prepared by weight parts of Curezol CIIZ CN so, 50 parts by weight of dioctyl phthalate, and 80 parts by weight of Sumidur L (aromatic polyisocyanate: Sumitomo Bayer Urethane Co., Ltd.) was added to 600 parts by weight of water, followed by Kuraray Boval PVA 205 (polyvinyl Add 8 parts by weight of alcohol (Kuraray Co., Ltd.) to an aqueous solution and stir and mix at 3.000 r, p, m for 2 minutes using a homomixer. , m
, while stirring, add 20 parts by weight of meta-xylene diamine.

Thereafter, the reaction was carried out at 40°C for 2 hours. The reaction product was filtered and washed with water to obtain 170 parts by weight of microcapsules having an average size of 25 μm.

2 parts by weight of the microcapsules, 100 parts by weight of HN-2200, and 80 parts by weight of Epicote 828 were mixed to form a one-component product, and the storage stability was measured at 40°C for 1 day.

Effects of the Invention The microcapsules of the present invention can be stored stably for a long period of time even when mixed with an epoxy compound.

Therefore, this is blended into an epoxy compound prepolymer,
Excellent storage stability - can be used as a curing agent for liquid adhesives, sealants, molding materials, casting materials, laminated materials, paints, etc.

Claims (1)

[Claims] 1. Microcapsules of an amine curing agent in which the core component contains an amine curing agent having a solubility in water of 10% by weight or less, and the shell wall component contains a polymer whose main polymerization component is a radically polymerizable monomer.