Siemens Aktiengesellschaft

Klaus Kretzschmar

Helmut Markert

Wolfgang Rogler

Klaus-Robert Hauschildt

Michael Schreyer

Wolfgang Kleeberg

Heinz Hacker

Peter Donner

Wolfgang Von Gentzkow

Peter Braun

Wolfgang Bendel

Klaus M&uuml;ller

Gerhard Piecha

Gu/ Nter Mennig

Oliver Eitel

In a process for the production of a flame-resistant, pourable, latently reactive, phenolically curable epoxy resin molding material for the encapsulating of electronic components, a latently reactive prepolymer epoxy resin mixture in powder form which is free of isocyanate groups is produced at reaction temperatures up to 200&deg; C. from a thermally polymerizable, filler-containing reaction resin mixture of polyepoxy resin consisting of a mixture of bi-functional and multi-functional epoxy resins and polyisocyanate resin having a molar ratio of the epoxy groups to the isocyanate groups of >1:1 with a substituted imidazole as reaction accelerator in a concentration of 0.5 to 2.5% by weight, relative to polyepoxy resin, and the prepolymer epoxy resin mixture is mixed with a powdered filler-containing phenolic resin mixture in a molar ratio of the epoxy groups to the phenolic hydroxyl groups of 1:0.4 to 1:1.1.

Blending epoxy resin-polyisocyanate-filler mixture and phenolic resin-filler mixture for molding

Epoxy resin moulding compounds having halogen-free flame retardation

Oxazolidinone structures-containing prepolymeric epoxy resin mixture

This invention relates to a method for the manufacture of molded material for an insulating component made of a quick-hardening reaction resin which employs a hardening catalyst. An object of the invention is to provide reaction resins which allow the manufacture of molded materials with increased dimensional heat resistance and at the same time, good mechanical properties. According to the invention, a reaction resin mixture of a polyepoxide and a polyisocyanate (EP/IC resin) with a formula mole ratio EP:IC of about 1 to 5 and a viscosity of up to about 7000 mPa.multidot.sec (at 25.degree. C.) is cross-linked under pressure by means of a tertiary amine or imidazole hardening catalyst at a gelling temperature of about 130.degree. to 150.degree. C. and is post-hardened at a temperature of 150.degree. to 200.degree. C. This produces a reaction resin molded material (OX/ICR molding material) containing oxazolidinone and isocyanurate rings with a mole ratio OX:ICR greater than 1 and, after hardening, the reaction of the epoxy and isocyanate groups of the EP/IC resin, is above about 90%.

Method for the manufacture of molded materials

The invention relates to a heat-hardened molded material produced from a resin mixture of a polyfunctional epoxide, a polyfunctional isocyanate and a reaction accelerator, which optionally contains additives and/or fillers. The objective is to make a resin mixture which permits the manufacture of a highly heat-resistant molded material, and which has at the same time a high-temperature cycle resistance and good mechanical properties. For this purpose, the polyfunctional epoxide of the resin includes a polyoxyalkylene glycol polyglycidyl ether.

Heat-hardenable reaction resin mixtures for impregnating and embedding

This application relates to methods for the manufacture of leakage current-proof epoxy-resin molded materials from epoxy resin mixture based on di- or polycarboxylic-acid glycidyl esters, di- or polyfunctional cycloaliphatic olefinic epoxides and dicarboxylic-acid anhydrides, carried out in such a manner that molded materials with good mechanical properties are obtained also for parts of large volume. For this purpose, the invention provides that, by means of the experimentally determined time necessary to reach the maximum temperature during the cross-linking of the epoxy resin mixture under quasi adiabatic conditions, the rate of cross-linking of the epoxy resin mixture is adjusted, by the addition of a diol or polyol, to at least as long as the time necessary to reach the maximum temperature during cross-linking of the glycidyl ester/dicarboxylic acid anhydride components.

Method for manufacturing epoxy resin molded materials

The invention relates to heat-hardenable reaction resin mixtures which contain polyfunctional epoxides, polyfunctional isocyanates and a reaction accelerator as well as, optionally containing customary additives and/or fillers. The invention has the object of achieving reaction resin mixtures which are stable in storage, consist of individual components that are easy to mix, exhibit a prolonged prehardening period and permit at the same time the manufacture of materials which combine the good mechanical properties and the high temperature-cycle resistance of polyurethane structures with the good thermal properties of oxazolidinone and isocyanurate structures. According to the invention, the reaction resin mixtures contain as polyfunctional isocyanates, isocyanate prepolymerisates in the form of reaction products of diphenyl methanediisocyanate and a diol, or of an isocyanate mixture of diphenyl-methanediisocyanate and a polymethylenepolyphenylisocyanate (with a functionality greater than 2) and a diol. The prepolymerisates utilize 0.01 to 0.35 equivalents and preferably 0.05 to 0.2 equivalents of the diol per 1 equivalent of isocyanate; the mixture contains 0.2 to 5 equivalents isocyanate per 1 equivalent of epoxy. The reaction accelerator is a tertiary amine or an imidazole.

Heat-hardenable reaction resin mixtures comprising polyfunctional

Molding materials, laminates, stratified material and cover or protective layers which are of high electrical and mechanical quality are formed from polymerisable epoxy compounds if the corss-linking of the epoxy resins is accomplished by anionic polymerisation, using mixed catalysts of tertiary amines of the formula: ##STR1## and an imidazoles of the formula: ##STR2## as a polymerisation catalysts.

Method for the manufacture of epoxy resin molding materials

Growing community of inventors

Erlangen, Germany

Klaus Kretzschmar