KR900000192B1 - Epoxy resin composition - Google Patents

Abstract

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Description

Epoxy resin composition

1 is a graph showing changes over time of the viscosity at 60 ° C. of the epoxy resin composition adjusted in Examples 1-4 and Comparative Examples 1-3.

The present invention relates to an epoxy resin composition for use in mold insulators used in electrical equipment. Cured products composed of epoxy resins and acid anhydrides have excellent electrical, mechanical, and chemical properties, and thus are widely used as epoxy resin mold insulators for electrical equipment and transmission and distribution equipment. As a method of shortening the release time in order to improve the productivity of the epoxy resin casting with a small mold, it is a manufacturing method generally called a pressure gelation method. In this manufacturing method, the mixture of the resin composition is put in a pressurized tank at low temperature and injected directly into the mold at a temperature higher than the resin mixture through the pipeline and the mold head at the time of molding, and at this time, pressurization is maintained to compensate for the curing shrinkage of the resin, It hardens in a short time and obtains a product. The epoxy resin mixture used in this production method is required to have a low viscosity in a low temperature pressurized tank, a long pot life, and a fast curing property in a high temperature mold.

As a general feature of epoxy resins, low viscosity at low temperatures is low molecular weight, so the curing shrinkage rate is very large, and therefore, defects such as shrinkage and cracking are likely to occur in the cured product. Fast reaction at high temperature is relatively easy to react even at low temperature and short pot life. In order to prevent these problems from shrinkage or cracking during the curing process, a pressure gelling method is employed, and a latent accelerator is used to prolong the pot life. However, the low molecular weight epoxy resin exhibiting low viscosity at low temperature is inferior in thermal shock resistance to the solid or high viscosity epoxy resins commonly used in ordinary casting methods other than the pressure gelling method. Conventionally, as a method of improving the thermal shock resistance of low-viscosity epoxy resins, a flexible impurity agent, for example, a method in which a main chain is added to a high molecular weight oligomer such as polyester, polyether or polybutadiene at a molecular weight of about 500-5,000 There are drawbacks such as remarkably high viscosity with increasing amount of addition and remarkably lowering of heat resistance. On the other hand, when the addition amount is small, the thermal shock resistance hardly improves. A flexible imparting agent that does not raise the viscosity of the resin mixture too much, for example, a polyamide such as a main chain has the disadvantage of high reactivity and short pot life.

The present invention, which is indispensable to the pressure gelation method, has the property of low viscosity at low temperature, long pot life, and rapid curing at high temperature, and must sacrifice any heat resistance or heat shock resistance of the conventional low viscosity epoxy resin. It is an object to obtain the epoxy resin composition which is excellent in heat shock resistance, without degrading heat resistance, as it was performed in order to solve the problem. That is, this invention is a bisphenol A represented by Formula (1) with respect to 100 weight part of polybasic carboxylic anhydrides as an epoxy resin (a) epoxy equivalent of 200 or less and (b) hardening | curing agent.

10-40 parts by weight and hydrogenated bisphenol A represented by formula (2)

Epoxy resin composition consisting of 10-40 parts by weight of a condensation mixture and an inorganic powder as a filler. Epoxy resins (a) having an epoxy equivalent of 200 or less used in the present invention may be used as long as they are liquid at low temperatures (20-80 ° C.) or when they exhibit liquid at low temperatures when mixed with a curing agent (b) condensation mixture. There is a number. For example, the following examples can use epoxy resin individually or in mixture of 2 or more types. That is, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolox type epoxy resin, cresol no block type epoxy resin, alicyclic lipoic ester-type epoxy resin, and alicyclic type containing epoxy group in the ring Epoxy resin, epoxy resin containing a spiro ring, Hydantoin epoxy resin, etc. are mentioned. The (b) condensation mixture used for this invention heats polybasic carboxylic anhydride, bisphenol A represented by Formula (1), and hydrogenated bisphenol A represented by Formula (2) to 100-150 degreeC in nitrogen gas atmosphere and a container. It is prepared by mixing until a uniform liquid. If desired, an accelerator, for example, an organic carboxylate metal salt, a tertiary amine, or the like may be added to the preparation.

As a polybasic carboxylic anhydride used for a condensation mixture, if it is a liquid at low temperature (20-80 degreeC), it can be used. For example, hexahydro phthalic anhydride, methyl hexahydro phthalic anhydride, tetrahydro phthalic anhydride, methyl tetrahydro phthalic anhydride, and the like can be used alone or in combination. It can mix and use 2 or more types. In the condensate (b), when the addition amount of bisphenol A represented by the formula (1) to 100 parts (parts by weight) of the polybasic carboxylic anhydride is less than 10 parts, high HDT ( The thermal deformation temperature and the following) cannot be obtained, and when the addition amount of the hydrogenated bisphenol A represented by the formula (2) is less than 10 parts, the thermal shock resistance of the cured product cannot be improved. In addition, when the addition amount of bisphenol A exceeds 40 parts and the addition amount of hydrogenated bisphenol A also exceeds 40 parts, the viscosity of the mixture of the epoxy resin and the inorganic powder filler at low temperature exceeds 100,000 CP (Centise Poise, below). Injection through a line becomes difficult, and cannot be used as a resin mixture of the pressure gelling mold method.

As the inorganic powder (c) used in the present invention, any material that does not degrade the electrical and mechanical properties may be used. Examples thereof include alumina powder, hydrated alumina powder, quartz powder, and fused quartz powder. It is not necessarily limited to these. In the epoxy resin composition of the present invention, the mixing ratio of (a) epoxy resin: (b) condensation mixture: (c) inorganic powder is preferably in the range of 100 parts: 50-150 parts: 200-600 parts.

The method for producing a mold using the epoxy resin composition according to the present invention comprises mixing (a) an epoxy equivalent of 200 or less epoxy resin, (b) a condensation mixture, (c) an inorganic powder and a desired accelerator at 20-80 ° C. Preferably, the epoxy resin composition obtained by vacuum mixing is injected directly into the mold preheated at 90-160 ° C. through a pipeline. The curing is then completed at 1-30 minutes while maintaining a pressure of 0.5-5.0 kg / cm 2 of gauge pressure to obtain the product.

The accelerator to be added to the epoxy resin composition may be, for example, metal carboxylate salts, octyl zinc, tertiary amines, boron trifluoride, amine complexes, imidasoles, and the like. no. The amount of accelerator added is adjusted so that curing is completed in 1-30 minutes at a mold temperature of 90-160 占 폚, and most preferably 0.1-8 parts is added.

The epoxy resin composition according to the present invention can be prepared by adding a colorant, a coupling agent, an internal mold release agent, and the like, without lowering the properties of the resin mixture, such as long-term pot life, rapid curing, and high HDT and thermal shock resistance. Next, the composition of this invention is demonstrated concretely based on an Example and a comparative example.

Example 1

100 parts of bisphenol A epoxy resin GY-260 (manufactured by cyba Geigy), 100 parts of methyl-THPA (tetrahydrophthalic anhydride) and 65 parts of condensation mixture obtained by mixing 30 parts of hydrogenated bisphenol A and zinc octylate 1 part and 390 parts of alumina powder were stirred under reduced pressure at 60 degreeC, and the epoxy resin composition was prepared. Initial viscosity, pot life, gelation time and viscosity over time of the obtained composition were measured by the following method. These results are shown in Table 1 and FIG. 1 (circle 1 in FIG. 1). Using the composition, the creek resistance test piece and the HDT test piece were prepared (gelled at 150 ° C., then cured at 130 ° C. for 24 hours), and evaluated by the following method. The results are shown in Table 1.

(Initial viscosity)

After preparing an hydroxy resin composition, the result of performing 15 minutes of reduced pressure stirring at 60 degreeC is measured.

(Housework time)

After preparing the epoxy resin composition, the viscosity was measured at an interval of 30 minutes at 60 ° C., and the time until the viscosity became 50,000 CP was measured.

(Gelling time)

The time until the epoxy resin composition was gelatinized by heating in 150 degreeC hot air drying furnace was measured.

(Time-lapse)

The epoxy resin composition was placed in a 60 ° C. container, installed in an oil bath of 60 ° C., and then subjected to viscosity measurements at 30 minute intervals to observe changes over time.

(Creck Index)

Using an epoxy resin composition, creep resistance test pieces were prepared and evaluated based on the International Electrotechnical Commission (IEC) recommendation method (RECOMMENDATION, publication 455-2).

(HDT)

Test pieces were prepared and evaluated based on ASTM-D648.

Table 1

Example 2

Condensation mixture obtained by mixing 20 parts of bisphenol A and 20 parts of hydrogenated bisphenol A with respect to 100 parts of GY-260 (manufactured by cyba Geigy) and 100 parts of methyl-THPA (tetrahydrophthalic anhydride) of bisphenol A epoxy resin, 65 parts, jade 1 part of zinc titanate and 390 parts of alumina powder were stirred under reduced pressure at 60 ° C. to prepare an epoxy resin composition. The properties of the obtained composition and the properties of the cured product were measured in the same manner as in Example 1. These results are shown in Table 1 and Fig. 1 (Table 1 in Fig. 1).

Example 3

Condensation mixture obtained by mixing 30 parts of bisphenol A and 10 parts of hydrogenated bisphenol A with respect to 100 parts of GY-260 (manufactured by cyba Geigy) and 100 parts of methyl-THPA (tetrahydrophthalic anhydride) of bisphenol A epoxy resin, 65 parts, jade 1 part of zinc titanate and 390 parts of alumina powder were stirred under reduced pressure at 60 ° C. to prepare an epoxy resin composition. The properties of the obtained composition and the properties of the cured product were measured in the same manner as in Example 1. These results are shown in Table 1 and FIG. 1 (△ table in FIG. 1).

Example 4

60 parts of condensation mixture obtained by mixing 30 parts of bisphenol A and 30 parts of hydrogenated bisphenol A with respect to 100 parts of GY-260 (manufactured by cyba Geigy) of bisphenol A epoxy resin and 100 parts of methyl-THPA (tetrahydrophthalic anhydride), jade 1 part of zinc titanate and 370 parts of alumina powder were stirred under reduced pressure at 60 ° C. to prepare an epoxy resin composition. The properties of the obtained composition and the properties of the cured product were measured in the same manner as in Example 1. These results are shown in Table 1 and FIG. 1 (circle 3 in FIG. 3).

Comparative Example 1

100 parts of GY-260 (manufactured by cyba Geigy) of bisphenol epoxy resin, 70 parts of methyl-THPA (tetrahydrophthalic anhydride), 1 part of octylic acid zinc and 400 parts of alumina powder were stirred under reduced pressure at 60 deg. It prepared. The properties of the obtained composition and the properties of the cured product were measured in the same manner as in Example 1. The results are shown in Table 1 and Fig. 1 (the? Table in Fig. 1).

Comparative Example 2

70 parts of condensation mixture obtained by mixing 5 parts of bisphenol A and 5 parts of hydrogenated bisphenol A with respect to 100 parts of GY-260 (manufactured by cyba Geigy) of bisphenol A epoxy resin and 100 parts of methyl-THPA (tetrahydrophthalic anhydride), jade 1 part of zinc chelate and 400 parts of alumina powder were stirred under reduced pressure at 60 ° C. to prepare an epoxy resin composition. The properties of the obtained composition and the properties of the cured product were measured in the same manner as in Example 1. These results are shown in Table 1 and Drawing 1 (Table 1 in Drawing 1).

Comparative Example 3

55 parts of condensation mixture obtained by mixing 50 parts of bisphenol A and 50 parts of hydrogenated bisphenol A with 100 parts of GY-260 (manufactured by cyba Geigy) of bisphenol A epoxy resin and 100 parts of methyl-THPA (tetrahydrophthalic anhydride), jade 1 part of zinc titanate and 360 parts of alumina powder were stirred under reduced pressure at 60 ° C. to prepare an epoxy resin composition. The characteristic of the obtained composition and the characteristic at the time of hardening were measured similarly to Example 1. The results are shown in Table 1 and Fig. 1 (x table in Fig. 1). In the above Examples and Comparative Examples, the filler concentration of the epoxy resin composition was about 70%, and the amount of the curing agent was blended in an equivalent ratio of 0.8 with respect to the epoxy resin.

The epoxy resin composition of the present invention is not only capable of obtaining a mold insulator excellent in both high HDT and thermal shock resistance, but also rich in productivity and quality stability. In addition, in the manufacturing process, the loss of resin can be reduced, thereby saving resources.

Claims (1)

(a) Epoxy resin having an epoxy equivalent of 200 or less, and (b) a hardener, represented by 10-40 parts by weight of bisphenol A represented by the following formula (1) and 100 parts by weight of the polybasic carboxylic anhydride and the following formula (2) Epoxy resin composition comprising 10-40 parts by weight of a condensation mixture of hydrogenated bisphenol A and inorganic powder as a filler.

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