Siemens Aktiengesellschaft

Gerhard Piecha

Wolfgang Rogler

Lothar Schoen

Helmut Markert

Juergen Huber

Klaus Kretzschmar

Peter Groeppel

Matthias Uebler

Casting compound suitable for casting an electronic module, in particular a large-volume coil such as a gradient coil, which is composed of a support material forming a matrix, one or more fillers made of inorganic microparticles, and at least one filler made of polymer nanoparticles.

Casting compound suitable for casting an electronic module, in particular a large-volume coil such as a gradient coil

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

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Nuremberg, Germany

Gerhard Piecha