JPS63304018A - Epoxy resin curing agent composition - Google Patents

Abstract

PURPOSE:To provide the titled acid anhydride-based composition of good storage stability while retaining excellent cure-promoting function, capable of curing at low temperatures in a short time, incorporated with a combination of, as the curing accelerator, an organic phosphine compound and amine compound. CONSTITUTION:The objective composition incorporated with a combination of, as the curing accelerator, (A) an organic phosphine compound (pref., arylphosphine compound, esp. triarylphosphine such as triphenylphosphine) and (B) an amine compound (pref., imidazole such as 2-ethyl-4-methylimidazole, and/or tertiary amine such as lauryl dimethylamine). Preferably, the amount of this composition to be incorporated in epoxy resin are such as to be 0.5-3pts. wt. based on 100pts.wt. of the epoxy resin for the components A and B, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an acid anhydride-based epoxy resin curing agent composition.

[Prior Art] Conventionally, casting resins for electrical parts, etc. have two components: a resin component consisting of an epoxy resin, an inorganic filler, a flame retardant, etc., and a curing agent component consisting of a liquid acid anhydride and a curing accelerator. It can be commercialized as a liquid, and among these, amine compounds such as imidazoles and tertiary amines are widely used as curing accelerators.

However, the viscosity of acid anhydride curing agent compositions containing such amine curing accelerators is high, and not only does it increase over time, carbon dioxide gas is generated and the container swells, and in extreme cases, the container may swell. It lacks storage stability as a curing agent component, such as rupturing.

The present inventors have discovered that organic phosphine compounds do not have the drawbacks of amine-based curing accelerators and have excellent curing accelerating functions, and have previously proposed them as a unique epoxy resin curing agent composition. (Special application 1986-1
No. 11187).

[Problems to be solved by the invention] In recent years, there has been a strong desire to lower the curing temperature to reduce the curing shrinkage rate and improve crack resistance, and to shorten the curing time to improve productivity. desired.

In order to satisfy such demands, it is sufficient to increase the amount of curing accelerator blended, but when an amine compound is used, the viscosity of the system increases and the tendency to generate carbon dioxide gas becomes even stronger. .

On the other hand, when an organic phosphine compound is applied as a curing accelerator, the curing agent composition has a low viscosity and good storage stability, and the prepared epoxy resin composition also has a low viscosity, so it can be used as a casting resin. Although it is useful, when the obtained cured resin product is left for a long period of time, its moisture resistance tends to decrease.

If moisture is present in the cured product, the electrical properties such as the dielectric constant, dielectric loss tangent, and insulation properties of the cured product will be reduced, and the durability of the product will also be reduced, leading to the occurrence of defective products. Therefore, the moisture resistance of a cured resin product is an important property in the field of various electrical components such as flyback transformers, capacitors, coils, and light emitting diodes.

The present inventors have conducted intensive studies to improve the long-term moisture resistance of the resulting cured product while maintaining the above-mentioned excellent properties of organic phosphine compounds. It was discovered that the long-term moisture resistance was synergistically improved by using the above in combination, and a curing agent composition that could fully satisfy the intended purpose was obtained, and based on this knowledge, the present invention was completed.

That is, an object of the present invention is to provide an acid anhydride-based epoxy resin curing agent composition that can prepare a cured product with improved long-term moisture resistance, has low viscosity, and has excellent storage stability. .

[Means for solving the problems 1 The acid anhydride-based epoxy resin curing agent composition according to the present invention is
It is characterized by containing an organic phosphine compound and an amine compound as a curing accelerator.

The organic phosphine compound refers to the general formula (1) L in which R1
, R2 and R3 represent a hydrogen atom, an alkyl group, an aryl group such as a phenyl group, a tolyl group, a cycloalkyl group such as a cyclohexyl group, and may be the same or different.

In addition, the following formula (2) (wherein R represents an alkylene group, R' and R'1 represent a hydrogen atom, an alkyl group, an aryl group such as a phenyl group, a tolyl group, or a cycloalkyl group such as a cyclohexyl group) may be the same or different.However, R' and R
It may also be an organic group containing an organic phosphine, such as a group represented by "except when R1 is a hydrogen atom. However, R1,
Except when R2 and R3 are all hydrogen atoms. ].

Specifically, tertiary phosphine compounds such as triphenylphosphine, tributylphosphine, tricyclohexylphosphine, and methyldiphenylphosphine, secondary phosphine compounds such as butylphenylphosphine and diphenylphosphine, and primary phosphine compounds such as phenylphosphine and octylphosphine. and tertiary bisphosphine compounds such as bis(diphenylphosphino)methane and 1,2-bis(diphenylphosphino)ethane,
One or more types selected from the group consisting of these are used. Among these, it is preferable to use arylphosphine compounds, and triarylphosphines such as triphenylphosphine and triphenylphosphine are preferable.

When an organic bosphin compound is used as a curing accelerator, the viscosity of the resulting epoxy resin composition is lower than when an amine compound is used, and impregnating properties into, for example, electrical parts are improved.

The amount of the organic phosphine compound blended is preferably 0.2 to 5 parts by weight, particularly preferably 0.5 to 3 parts by weight, based on 100 parts by weight of the epoxy resin. If the amount is less than this range, it will be difficult to obtain the desired effect. On the other hand, if the amount exceeds the above range, the moisture resistance of the resulting cured product will be significantly reduced.

As the amine compound, any compound conventionally used as a curing accelerator for epoxy resins is sufficient, and imidazoles and tertiary amines are recommended, for example.

Specifically, the imidazoles include 2-ethyl-4-methylimidazole (hereinafter referred to as r2E4MZJ);
2-Methylimidazole, 1-benzyl-2-methylimidazole, 2-undecylimidazole, 2-phenylimidazole, 1-cyanoethyl-2-ethyl-4-
Examples include methylimidazole.

In addition, as the tertiary amine, lauryldimethylamine,
Dicyclohexylamine, dimethylbenzylamine, dimethylaminomethylphenol, 2.4.6-tris(
N,N-dimethylaminomethyl)phenol (FD
It is called MP-30j. ), 1,8-diazabicyclo(
Examples include 5,4,0>undecene-7 and the like.

Further, modified products of these amine compounds such as Lewis acid salts, organic acid salts, and adducts are also suitable compounds.

The blending amount of such amine compound is 100% of epoxy resin.
It is preferably 0.2 to 5 parts by weight, particularly preferably 0.5 to 3 parts by weight. If the amount is less than this range, it is difficult to obtain the desired effect. On the other hand, if a matrix exceeding the above range is blended in order to cure at a low temperature and in a short time, the generation of carbon dioxide cannot be ignored even if an organic phosphine compound is used in combination, and the long-term storage stability of the curing agent component There is a tendency for sexual performance to decline.

The curing agent component is mainly composed of a curing accelerator in an amount corresponding to the above-mentioned predetermined amount and a liquid carboxylic acid anhydride as an epoxy resin curing agent.

The liquid carboxylic acid anhydride is preferably a liquid at 25°C.

Specifically, 3-methyltetrahydrophthalic anhydride, 4
-Methyltetrahydrophthalic anhydride (hereinafter referred to as rMe-THPAJ) such as methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride (hereinafter referred to as rMe-THPAJ) such as 3-methylhexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, etc. rMe-HHPAj), methylnadic anhydride, dodecenylsuccinic anhydride and their structural or geometric isomers, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, phthalic anhydride, trimellitic anhydride Examples include those obtained by mixing and modifying with an acid anhydride that is solid at room temperature, such as benzyphenone tetracarboxylic anhydride, and liquefying it.

These carboxylic acid anhydrides may be used alone, or two or more types may be used in combination as appropriate.

The blending amount is 0.5 per epoxy equivalent of the epoxy resin.
It is preferable that it is 1.5 equivalents.

The epoxy resin curing agent according to the present invention is applied to, for example, a flame-retardant epoxy resin containing an epoxy resin, an inorganic filler, and a flame retardant as resin components.

The epoxy resin is not particularly limited, and specifically includes glycidyl ether type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, Talezol novolac type epoxy resin, and glycidyl ester type. Examples include epoxy resins, glycidylamine type epoxy resins, cycloaliphatic epoxy resins, heterocyclic epoxy resins, halogenated epoxy resins, and these may be used alone or in combination of two or more.

For example, in order to improve the impregnating properties of electrical parts, etc., it is preferable to use an epoxy resin that is liquid at room temperature.
A maximum of about 300 is recommended. If the epoxy equivalent is higher than this, the viscosity becomes high and the desired effect tends to decrease.

Incidentally, an epoxy resin that has been liquefied by using a diluent or the like can also be used within the allowable range in terms of physical properties.

Inorganic fillers include hydrated alumina, silicon dioxide, kaolin clay, talc, glass fiber, calcium silicate, calcium carbonate, barium sulfate, magnesium oxide,
Examples include titanium oxide and boron nitride.

The amount of the inorganic filler blended is 85 to 300 parts by weight, preferably 150 to 250 parts by weight, per 100 parts by weight of the epoxy resin. If the amount is less than this range, it will be difficult to obtain the desired effect, and if it is too much, the viscosity of the composition will increase, which is not preferable in terms of product design.

Two or more types of inorganic fillers and agents may be used in combination, and a preferred system is exemplified by a mixed system of hydrated alumina, calcium carbonate, and silicon dioxide. In this case, epoxy resin 10
0 parts by weight, 85 to 190 parts by weight of hydrated alumina,
Contains 75 to 150 parts by weight of calcium carbonate and/or 0 to 90 parts by weight of silicon dioxide, and the total amount of inorganic fillers is 3 parts by weight.
A composition of not more than 0.00 parts by weight of inorganic filler is preferred.

Furthermore, if necessary, a female combustion agent exemplified by halogen compounds such as antimony trioxide, hexabromobenzene, decabromodiphenyl oxide, tetrabromobisphenol A1 brominated cresol monoglycidyl ether, and phosphorus compounds such as red phosphorus is blended. be able to. In addition, natural or synthetic waxes, metal soaps, fatty acid amides, esters, mold release agents such as paraffins, colorants such as carbon black, silane coupling agents, diluents,
It is also possible to use an antisettling agent, an antifoaming agent, a plasticizer, an antioxidant, etc. in combination as appropriate.

The curing agent composition according to the present invention is generally prepared by stirring and mixing predetermined amounts of raw material components, ie, carboxylic acid anhydride and curing accelerator, at room temperature or under heating.

Furthermore, the resin component is processed by mixing a predetermined amount of epoxy resin and an inorganic filler as necessary at room temperature or under heating using a mixer such as a Henschel mixer, a Banbury mixer, an extruder, a hot roll, or a kneader. Prepare.

The order of blending the raw materials for both the curing agent composition and the resin composition does not matter. Furthermore, if necessary, the system may be depressurized and degassed at room temperature or under heating.

The epoxy resin composition obtained by suitably blending the above-mentioned components is useful for casting various electronic components such as coils and capacitors as well as for casting flyback transformers.

[Example] The present invention will be explained in detail with reference to Examples and Comparative Examples below.

Example (1) A predetermined amount of triphenylphosphine and an amine compound were blended with 82 parts by weight of Me-TI-fPA, and 7
The mixture was mixed with stirring for 30 minutes under heating at 0° C. to obtain a curing agent composition. The viscosity of the curing agent composition was measured at 25° C. using a B-type viscometer. Furthermore, a curing agent composition having the same composition as above was stored at 40°C for one month, and the amount of carbon dioxide gas generated at that time was measured according to JIS K-230.
Measured according to 1. The results obtained are shown in Table 1.

(2) Bisphenol A type epoxy resin (epoxy resin
f1190>, hydrated alumina (average particle size 3.5 μ) and calcium carbonate (average particle size 3.0
A resin composition was obtained by blending the curing agent component obtained above with the resin component obtained by stirring and mixing a predetermined amount of .mu.

Table 2 shows the results of measuring the gelation time and viscosity of the resin composition. Here, the gelation time is JIS C
-2105 at 75°C, and the viscosity was measured at 25°C using a B-type viscometer.

Furthermore, the completely cured product of the resin composition was heated at 121°C and 2.2°C.
It was left under the water vapor pressure of ATM [pressure tester test (hereinafter referred to as rPcTJ)] for 224 hours and 8 hours.
Water absorption rate of cured product after 7 hours (measured from increase in weight of test object) and dielectric loss tangent (tan δ: %) (25°C, 1
Moisture resistance was evaluated according to 0 KHz: JISK-6911). The results obtained are listed in Table 2.

Comparative Example The amount of carbon dioxide gas generated from a curing agent composition obtained by using an amine compound or triphenylphosphine alone as a curing accelerator, and the moisture resistance of a completely cured product obtained using the curing agent component were measured according to the examples. It was evaluated. The obtained results are listed in Tables 1 and 2, respectively.

Reference Example The moisture resistance of the cured product of the epoxy resin composition was evaluated under low temperature and short-time conditions.
We selected various curing agent compositions necessary to achieve a gelation time of 70 minutes when cured at °C, and the moisture resistance of the completely cured epoxy resin obtained using the curing agent compositions, and the relationship between triphenylphosphine and 2F4M7. The correlation with which fraction is shown in FIG.

Here, the blending amounts of triphenylphosphine and 2-day 4MZ were varied, and the other components were the same as in Example 2. Further, the long-term moisture resistance of the cured resin product was evaluated using tan δ at 87 hours PCT.

[Effect of the invention] The epoxy resin curing agent composition obtained by using an amine compound in combination with an organic phosphine compound as a curing accelerator has the following properties:
It has good storage stability and can be cured at low temperatures in a short time while maintaining an excellent curing accelerating function.

Furthermore, since the resin composition to which such a curing accelerator is applied has low viscosity, it maintains high impregnating properties, and the resulting cured resin product has excellent long-term moisture resistance, so it is particularly required to have insulation properties. It is useful as a casting resin composition in the field.

[Brief explanation of the drawing]

FIG. 1 shows the correlation between the composition of the curing accelerator and the moisture resistance of the cured product. (Margin below)

Claims (3)

[Claims] (1) An acid anhydride-based epoxy resin curing agent composition characterized in that an organic phosphine compound and an amine compound are used together as a curing accelerator. (2) The acid anhydride-based epoxy resin curing agent composition according to claim 1, wherein the organic phosphine compound is an arylphosphine compound. (3) Claim 1, characterized in that the amine compound is an imidazole and/or a tertiary amine.
The acid anhydride-based epoxy resin curing agent composition described in 1.