KR950006811B1 - Liquid epoxy resin composition - Google Patents

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Description

Liquid Epoxy Resin Composition

The present invention relates to a liquid epoxy resin composition. In more detail, the present invention relates to a liquid flame-retardant epoxy resin composition excellent in impregnation and capable of imparting excellent moisture resistance to the cured product.

Conventionally, epoxy resins are widely used as casting resins such as high-pressure electric parts. Moreover, when hardening an epoxy resin composition, the acid anhydride type hardening | curing agent and amine type hardening accelerators, such as a tertiary amine and an amidazole, are used together normally.

Epoxy resin compositions used by molding into high-pressure electric parts or the like require various properties such as insulation, impregnation, moisture resistance, hardenability, thermal shock, thermal conductivity, and flame retardancy, and are generally evaluated as quality characteristics. Reality.

In general, in order to improve the flame retardancy and thermal conductivity of the resin composition, it is effective to add a large amount of inorganic filler to the resin composition, but the viscosity of the resin composition increases with the increase in the amount of filler, and as a result, The impregnation, mold, etc. of the work becomes difficult, and in extreme cases, improper impregnation may cause problems such as corona degradation and dielectric breakdown of the high-voltage electric parts.

Impregnation of the epoxy resin composition is an important characteristic especially for high-pressure electrical components. For example, in order to improve the impregnation of the transformer coil, various diluents, for example, esters, monoglycidyl ethers, etc. may be added to the epoxy resin composition. The method of reducing the viscosity of is proposed. However, low viscosity requires the use of a large amount of diluent, but in excessively many cases, problems such as lowering of the heat resistance temperature and increasing water absorption rate are limited, and thus the method can be sufficiently satisfied. It is not there.

An object of the present invention is to provide an epoxy resin composition having a low viscosity and good impregnation as a result of mixing a large amount of a flame retardant inorganic filler.

Another object of the present invention is to provide an epoxy resin composition having good properties such as insulation, moisture resistance, hardenability, thermal shock resistance, and thermal conductivity, in particular moisture resistance.

According to the present invention, (A) an epoxy resin, (B) liquid carboxylic anhydride, (C) an inorganic filler containing hydrated alumina and calcium carbonate, (D) an organic phosphine compound, and (E) an organic phosphate ester An epoxy resin composition is provided.

The epoxy resin (A) used in the present invention is not particularly limited and conventionally known ones in this field can be widely used, and specifically, bisphenol A type epoxy resins, bisphenol F type epoxy resins, and phenol novolac type epoxy resins. And glycidyl ether type epoxy resins such as cresol novolac type epoxy resins, glycidyl ester type epoxy resins, glycidylamine type epoxy resins, cyclic aliphatic epoxy resins, heterocyclic epoxy resins, halogenated epoxy resins, and the like. Can be. These epoxy resins are used individually by 1 type or in mixture of 2 or more types.

In the present invention, in order to improve the impregnation of the high-pressure electric parts and the like, it is preferable to use a liquid epoxy resin at room temperature, and the epoxy equivalent is preferably about 250 at most. As the epoxy resin which has more epoxy equivalent, the resin composition obtained becomes high viscosity, and since the desired objective of this invention becomes difficult to achieve, it is not preferable. In the present invention, an epoxy resin which is a solid at room temperature may be used, and any epoxy resin which is liquefied using a diluent or the like within the allowable range of the physical phase can be used without any problem.

In this invention, as a liquid carboxylic anhydride (B) used as an epoxy resin hardening | curing agent, a compound which is liquid at 25 degreeC is recommended. Specific examples of such carboxylic anhydrides include methyl tetrahydrophthalic anhydride (hereinafter referred to as "Me-THPA") such as 3-methyltetrahydrophthalic anhydride and 4-methyltetrahydrotephthalic anhydride, and 3-methylhexahydroanhydride. Methylhexahydrophthalic anhydride (hereinafter referred to as "Me-THPA"), such as phthalic acid and 4-methylhexahydrophthalic anhydride, methylnadic acid anhydride, dodecenyl anhydrovabagan and hexa, including structural isomers or geometric isomers The thing which mixed-modified and liquefied with solid acid anhydride at room temperature, such as hydrophthalic anhydride, tetrahydrophthalic anhydride, a phthalic anhydride, trimellitic anhydride, and benzophenone tetracarboxylic anhydride, can be illustrated. Carboxylic anhydrides may be used independently, respectively and may use 2 or more types together suitably. Of these carboxylic acids, Me-THPA and Me-HHPA are good because of their low viscosity, and among them, the viscosity of 3-Me-THPA and a mixture of carboxylic anhydrides containing 50% by weight or more is particularly preferable because it is 50 cps or less at 25 ° C. Do.

As a compounding quantity of carboxylic anhydride, it is good to set it as about 0.5-1.5 equivalent normally per 1 equivalent of epoxy resin of epoxy resin used, Preferably it is about 0.7-1.0 equivalent. When the blending amount of the carboxylic anhydride is less than the above range, the heat resistance, electrical properties, mechanical strength, etc. are lowered. On the contrary, when the blending amount of the carboxylic anhydride is more than the above range, the moisture resistance and the electrical properties tend to decrease. This is undesirable.

The inorganic filler (C) used in the present invention contains hydrated alumina and calcium carbonate as essential components. Here, the hydrated alumina is a powder represented as Al ₂ O ₃ · 3H ₂ O. In the present invention, a plurality of other inorganic fillers may be used together with hydrated alumina and calcium carbonate. As such an inorganic filler, silicon dioxide, kaolin crayfish, talc, glass fiber, calcium silicate, calcium carbonate, barium sulfate, magnesium oxide, titanium oxide, boron nitrite, etc. are mentioned, for example.

As a compounding quantity of an inorganic filler, it is about 80-400 weight part normally per 100 weight part of epoxy resins, Preferably it is about 120-310 weight part. When the blending amount of the inorganic filler is less than the above range, the intended purpose of the present invention becomes difficult to be achieved. On the other hand, when the blending amount of the inorganic filler is more than the above range, the viscosity of the resulting resin composition increases, which is not preferable in product design. Can not do it. As a compounding quantity of hydrated alumina, about 65-160 weight part is preferable with respect to 100 weight part of epoxy resins, and about 55-150 weight part is preferable with respect to 100 weight part of epoxy resins as a compounding quantity of calcium carbonate. That is, the degree of hydrated alumina and calcium carbonate is suitable. When the amount of the quantum sum is less than the above range, the flame retardancy of the resulting resin composition tends to be insufficient. On the other hand, when the amount of the quantum sum is more than the above range, the viscosity of the resulting resin composition is not preferable.

When using other inorganic fillers together with hydrated alumina and calcium carbonate, it is particularly suitable to use silicon dioxide as another inorganic filler. The mechanical strength of the resin composition obtained by the compounding of silicon dioxide, the improvement of moisture resistance, etc. can be aimed at. In this case, although it is possible to use in the range which silicon dioxide does not exceed 75 weight part with respect to 100 weight part of epoxy resins, it is good that the total amount of hydrated alumina and silicon dioxide does not exceed 160 weight part. When the total amount of hydrated alumina and silicon dioxide exceeds 160 parts by weight, the viscosity of the resin composition becomes high and impregnation tends to decrease, which is not preferable.

The composition according to the present invention is characterized by using an organic phosphine compound (D) as a curing accelerator, which is particularly effective for obtaining a low viscosity composition. As an organic phosphine compound, a conventionally well-known thing can be used widely, For example, the compound represented by following General formula (1) is mentioned.

[In formula, R <^1> , R <^2> and R <^3> is the same or different, and cycloalkyl groups, such as aryl groups, such as a hydrogen atom, an alkyl group, a phenyl group, and a tolyl group, and a cyclohexyl group, (Wherein R represents an alkylene group and P ′ and R ″ are the same or different and represent a cycloalkyl group such as an aryl group such as a hydrogen atom, an alkyl group, a phenyl group, a tolyl group, or a cyclohexyl group). An organic group containing an organic phosphine such as R ″ together with hydrogen atoms is excluded. Except that R ¹ , R ² and R ³ are all hydrogen atoms.]

As a specific example of the compound represented by the said General formula (1), Third phosphine compounds, such as a triphenyl phosphine, a tributyl phosphine, a tricyclohexyl phosphine, a methyl diphenyl phosphine, a butylphenyl phosphine, a diphenyl A second phosphine compound such as phosphine, a first phosphine compound such as phenylphosphine, octylphosphine and a third such as bis (diphenylphosphino) methane and 1,2-bis (diphenylphosphino) ethane Bis phosphine compounds can be exemplified.

In this invention, the said organic phosphine compound can be used individually by 1 type or in mixture of 2 or more types. Among the organic phosphine compounds, aryl phosphine compounds are preferable, and triaryl-phosphine such as triphenyl phosphine is particularly suitable.

As a compounding quantity of an organic phosphine compound, it is about 0.2-5 weight part normally per 100 weight part of epoxy resins, Preferably it is about 0.5-3 weight part. If the blending amount of the organic phosphine compound is less than the above range, the intended purpose of the present invention becomes difficult to be achieved. On the other hand, even if the blending amount of the organic phosphine compound is more than the above range, there is no significant difference in effect. Also not desirable.

As a hardening accelerator of the epoxy resin composition which concerns on this invention, an organic phosphine compound and an amine compound can be used together. By blending an amine compound, excellent moisture resistance can be imparted to the cast product of the epoxy resin composition. As the amine compound, amidazoles and tertiary amines are recommended, and various compounds used in combination with an acid anhydride curing agent are used. Specific examples of the imidazoles include 2-ethyl-4-methylimidazole (hereinafter referred to as "2E4MZ"), 2-methylimidazole, 1-benzyl-2-methylimidazole, and 2-undecyl Imidazole, 2-phenylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole and the like are exemplified. As the tertiary amine, specifically, lauryldimethylamine, dicyclohexylamine, dimethylbenzylamine, dimethylaminomethylphenol, 2,4,6-tris (N, N-dimethylaminomethyl) phenol (hereinafter referred to as "DMP -30 "), 1, 8- diazabicyclo (5, 4, 0) undensene-7, etc. can be illustrated. Moreover, modified compounds by Lewis acid salt, organic acid salt, adduct formation, etc. of these amine compounds are also suitable compounds.

As a compounding quantity of an amine compound, about 0.2-5 weight part is preferable per 100 weight part of epoxy resins, and about 0.5-3 weight part is especially preferable. When the compounding amount of the amine compound is less than the above range, the desired effect is less likely to be expressed. On the other hand, when the compounding amount of the amine compound is more than the above range, the pot life is shortened and the calorific value of the cured product is increased, thereby increasing the internal stress. As a result, problems such as crushing of the cured product arise, which is undesirable.

As an organic phosphate ester (E) used for this invention, the mono and / or diorganophosphate ester represented by following General formula (2) is mentioned as an example.

을 표시하는 데, 여기서 R⁶는 탄소수 3~22의 알킬기, 탄소수 3~22의 알케닐기, 시클로헥실기, 페닐기, 치환기로서 탄소수 1~18의 알킬기를 가지는 페닐기, 아크릴기 또는 메타크릴기를, R⁷은 수소원자 또는 메틸기를, n은 0 또는 1~30의 정수를 각각 나타내며, 단 R⁴및 R⁵는 동시에 수소원자인 경우는 없다.][Wherein, R ⁴ and R ⁵ are the same or different and represent a hydrogen atom or a group

Wherein R ⁶ is an alkyl group having 3 to 22 carbon atoms, an alkenyl group having 3 to 22 carbon atoms, a cyclohexyl group, a phenyl group, a phenyl group having an alkyl group having 1 to 18 carbon atoms as a substituent, an acryl group or a methacryl group; ⁷ represents a hydrogen atom or a methyl group, n represents an integer of 0 or 1 to 30, respectively, provided that R ⁴ and R ⁵ are not simultaneously hydrogen atoms.]

Specific examples of the organic phosphate ester represented by the general formula (2) include propyl phosphate, butyl phosphate, amyl phosphate, hexyl phosphate, heptyl phosphate, octyl phosphate, nonyl phosphate, decyl phosphate, lauryl phosphate and myristyl phosphate. Base phosphate, stearyl phosphate, behenyl phosphate, propenyl phosphate, butenyl phosphate, pentenyl phosphate, hexenyl phosphate, heptenyl phosphate, octenyl phosphate, nonenyl phosphate, decenyl phosphate, oleyl phosphate These polyoxyalkylene adducts etc. are illustrated with monoesters and corresponding diesters, such as phosphate, cyclohexyl phosphate, phenyl phosphate, toluyl phosphate, acryloxy phosphate and methacryloxy phosphate. Among these, decyl phosphate, lauryl phosphate, myristyl phosphate, palmityl phosphate, stearyl phosphate, and these polyoxyalkylene adducts are suitable.

As a compounding quantity of an organic phosphate ester, about 100 weight part of epoxy resins, about 0.03-1 weight part normally, It is good to set it as about 0.05-0.4 weight part preferably. When the compounding quantity of an organophosphate ester becomes larger than the said range, the viscosity of the resin composition obtained will rise and the impregnability of this composition will fall, and conversely, when the compounding quantity becomes smaller than the said range, moisture resistance will tend to fall In this case, neither is preferable.

A flame retardant can be mix | blended with the resin composition of this invention. Examples of the flame retardant include antimony compounds such as antimony triphase, phosphorus compounds such as hexabromobenzene, decabromodiphenyl oxide, halogen compounds such as tetrabromobisphenol A and brominated cresol monoglycidyl ether, and red Can be mentioned.

In addition, the resin composition of the present invention includes a release agent such as natural or synthetic waxes, metal soaps, fatty acid amides, fatty acid amides, esters, paraffins, colorants such as carbon black, silane coupling agents, diluents, antisettling agents, A defoaming agent, a plasticizer, antioxidant, etc. can also be mix | blended suitably.

The resin composition which concerns on this invention is prepared as follows as an example. That is, a predetermined amount of epoxy resin and inorganic filler are mixed and treated by a mixer such as Henschel mixer, Benbury mixer, extruder, furnace, kneader, etc. at room temperature or warming, and the carboxylic anhydride and the organic phosphine compound (curing What is necessary is just to add a predetermined amount) and an organic phosphate ester. In this case, the order of blending the raw material components is irrelevant, and the resin composition may be prepared by blending predetermined raw materials at once. If necessary, the system may be degassed under reduced pressure at room temperature or under heating.

The epoxy resin composition thus obtained has a low viscosity, and as a result, impregnation is good, and various properties such as insulation, moisture resistance, hardenability, thermal shock, thermal conductivity, and flame resistance are particularly good. Therefore, the epoxy resin composition of the present invention can be effectively used in a field in which insulation properties such as casting of various electric parts such as coils and capacitors, etc., are required in addition to the casting of the fryer back transformer.

An Example and a comparative example are given to the following, and this invention is demonstrated more clearly.

Example 1

100 parts by weight of bisphenol A type epoxy resin (epoxy equivalent 190), 160 parts by weight of hydrated alumina (average particle size 7 μ) and 60 parts by weight of calcium carbonate as inorganic fillers, Me-THPA (Licashed MT), which is a carboxylic anhydride. The curing agent solution obtained by dissolving 2 parts by weight of triphenyl phosphine and 0.2 parts by weight of dodecyl phosphate was added to 82 parts by weight of -500, manufactured by Shin-Ni Hong Lika Co., Ltd., to obtain an epoxy resin composition of the present invention. It was 59 poise (P) when the composition viscosity after degassing by vacuum was measured on 25 degreeC temperature conditions with the Brookfield viscometer.

It was 1.9% when the composition measured the hygroscopicity of the hardened | cured material obtained under the curing conditions of 120 degreeC-3 hours by the pressure cook cook (121 degreeC, 1.2 kg / cm <2>, 50 hours).

EXAMPLES 2-5

Bisphenol A type epoxy resin (epoxy equivalent 190) was used as an epoxy resin, hydrated alumina (average particle diameter 7 microns), calcium carbonate (average particle size 3 microns), and silicon dioxide (average particle size 9 microns) were used as a carboxylic anhydride as an inorganic filler. THPA (Licashed MT-500, manufactured by Shin-Ni Hong Lika Co., Ltd.), triphenylphosphine as an organic phosphine compound, dodecyl phosphate as an organic phosphate ester, and polyoxyethylene myristyl phosphate are shown in Table 1 below. It mix | blended by the composition and obtained the epoxy resin composition of this invention.

The viscosity in 25 degreeC of the obtained epoxy resin composition, and the hygroscopicity of hardened | cured material were measured like Example 1. A result is combined with Table 1 and shown.

Comparative Example 1

An epoxy resin composition was obtained in the same manner as in Example 2 except that DMP-30 was used as the curing accelerator. The viscosity at 25 degrees C of the obtained epoxy resin composition, and the hygroscopicity of hardened | cured material were measured according to Example 1. The obtained results are shown in Table 1.

Comparative Example 2

An epoxy resin composition was obtained in the same manner as in Example 2 except that the organophosphate ester was not used. The viscosity at 25 degreeC of the obtained epoxy resin composition, and the hygroscopicity of hardened | cured material were measured according to Example 1. The obtained results are shown in Table 1.

TABLE 1

Organophosphate ester A: dodecyl phosphate.

Organophosphate ester B: Polyoxyethylene myristyl phosphate.

Claims (10)

(A) Epoxy resin, (B) 0.5-1.5 equivalents of liquid carboxylic anhydride per 1 equivalent of epoxy of the epoxy resin, (C) 80-400 parts by weight of hydrated alumina and calcium carbonate per 100 parts by weight of the epoxy resin A liquid epoxy resin comprising a filler, (D) 0.2 to 5 parts by weight of an organic phosphine compound per 100 parts by weight of the epoxy resin, and (E) 0.03 to 1 part by weight of an organic phosphate ester per 100 parts by weight of the epoxy resin. Composition. The liquid epoxy resin composition according to claim 1, wherein the epoxy resin (A) is a liquid epoxy resin and its epoxy equivalent is at most 250. The liquid epoxy resin composition according to claim 1, wherein the liquid carboxylic anhydride (B) is liquid at 25 ° C. The liquid epoxy resin composition according to claim 1, wherein the liquid carboxylic anhydride (B) is methyl tetrahydro phthalic anhydride. The liquid epoxy resin composition according to claim 2, wherein the liquid carboxylic anhydride (B) contains 50% by weight or more of 3-methyl tetrahydro phthalic anhydride. The liquid epoxy resin composition according to claim 1, wherein 65 to 160 parts by weight of hydrated alumina and 55 to 150 parts by weight of calcium carbonate are blended with 100 parts by weight of the epoxy resin (A) as the inorganic filler (C). . The inorganic filler (C) is blended with 65 to 160 parts by weight of hydrated alumina, 55 to 150 parts by weight of calcium carbonate and 0 to 75 parts by weight of silicon dioxide, according to claim 1, based on 100 parts by weight of epoxy resin (A). Wherein the total amount of hydrated alumina and silicon dioxide does not exceed 160 weights. The liquid epoxy resin composition according to claim 1, wherein the organic phosphine compound is an aryl phosphine compound. The liquid epoxy resin composition according to claim 8, wherein the aryl phosphine compound is triphenylphosphine. The method of claim 1 wherein the organic phosphate ester is of the general formula:

[Wherein, R ⁴ and R ⁵ are the same or different, and a hydrogen atom or a group

Wherein R ⁶ represents an alkyl group having 3 to 22 carbon atoms, an alkenyl group having 3 to 22 carbon atoms, a cyclohexyl group, a phenyl group, a phenyl group having an alkyl group having 1 to 18 carbon atoms as a substituent, an acryl group or a methacryl group, and R ⁷ represents a hydrogen atom or a methyl group, n represents an integer of 0 or 1 to 30, provided that R ⁴ and R ⁵ are not hydrogen at the same time. Resin composition.