DE3229558C2 - Impregnation casting compound for electrical components - Google Patents

Abstract

A hardenable potting compound is proposed which is used for impregnating and potting electrical components and consists of a resin, a hardener, an accelerator and a filler. An epoxy based on bisphenol A and cycloaliphatic with a viscosity of <5000 mPas at 25 ° C is used as the resin, a modified dicarboxylic acid anhydride as the hardener, an imidazole as the accelerator and chalk as the filler. The filler is preferably contained in an amount of more than 53% by weight, based on the total mass. The proposed potting compound has a low viscosity, so that impregnation and potting can be carried out in a single operation. The coefficient of thermal expansion and the volume shrinkage are smaller than in the case of commercially available compounds and the potting compound has a high glass transition point, which leads to a high resistance to heat and temperature changes in the compound. the artificial penis with the sensory probes is inserted into the vagina to remove the gl

Description

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An epoxy resin based on bisphenol is used A and a cycloolefin in a ratio of 70:30 parts by weight, which at 25 ° C has a viscosity of less than 5000 mPa · s has. For this purpose, a modified carboxylic acid anhydride is used, z. B. Phialsäureanhydrld as a hardener, and an imidazole, z. B. pyrazole as an accelerator and chalk as

Claims (1)

Claim: Imprägniervergußmas -ä for electrical components, which consists of a resin, a hardener, an accelerator and a filler, characterized in that an epoxy based on bisphenol A and cycloolefin in a ratio of 70:30 parts by weight with a viscosity <5000 mPas at 25 ° C, a modified dicarboxylic acid anhydride as a hardener, an imidazole as an accelerator and chalk as a filler in an amount of 53 to 60% by weight, based on the total mass, and resin, hardener and accelerator a ratio of 100: 100: 0.5 parts by weight. 10 15th Filler added, resin, hardener and accelerator being used in a ratio of 100: 100: 0.5 parts by weight Weiden and the filler in an amount of 55 wt .-%, based on the total mixture, added will. The whole thing is mixed well and then makes a low-viscosity mass. To impregnate and cast a high-voltage ignition coil, first the layer winding dried, the disc winding heated to a temperature of about 100 ° C, the Storage container in which the potting compound is located, evacuated in order to degas the potting compound, and finally the impregnation and potting are carried out under vacuum. After demolding, the Sealing compound finally hardened, initially for an hour and a half at 90 ° C. and then for another 2 hours at 120 ° C. In the case of this impregnator potting compound described the following properties result: The invention is based on a casting compound according to the preamble of the main claim. Commercially available potting compounds of this type, with which electrical components are umgös sen to protect them from mechanical effects, and which consist of a curable resin, show a relatively low cure for two hours at 80 ° C. and then for two hours at 120 ° C. glass transition point of 80 ° C, relatively high linear thermal expansion coefficient between 44 and 129.10 ^"6 1 / ° C at 50 or above 90 ⁰ C, and a volume shrinkage, the 2.2% also relatively 1st large. Finally, these resins have with more than 10,000 mPa · s at 25 "C has a relatively high viscosity, which leads to casting compounds with which perfect impregnations, for example of electrical coils, are difficult to achieve. In the case of these commercially available casting compounds, the resistance to temperature changes, for example for use in high-voltage ignition coils in motor vehicles, is also not sufficient, which is related to the low glass transition point, as mentioned above. Advantages of the invention The impregnation potting compound according to the invention with the characterizing features of the main claim has the advantage that it has a low Viscosity, a small coefficient of thermal expansion, a high glass transition point as well tine has high thermal shock resistance and heat resistance; so are high voltage ignition coils, impregnated with this sealing compound according to the invention and poured, between at least -40 ° C and at least 120 ° C resistant to temperature changes and electrically functional at temperatures in the winding of more than 100 ° C. Due to the low viscosity makes it possible to impregnate such electrical components in one operation and to envelop. Description of an implementation area Viscosity 25 ° C <10000 mPas 60 ° C <1,000 mPas Glass transition point approx. 140 ° C Volume loss 1.5% Linear therm. Expansion coefficient up to 110 ° C 38 x 10- «1 / ° C 110 to 130 ° C 57 · ΙΟ " ⁶ 1 / ° C > 130 ° C 115 · ΙΟ " ⁶ 1 / ° C The impregnated on the catfish described and Cast ignition coils are resistant to temperature changes from at least -40 ° C to at least 120 ° C and are electrically functional at Temperatures in the winding of more than 100 ° C.