US 5,496,892 AGranted

Oxazolidinone structures-containing prepolymeric epoxy resin mixture

AssigneeSiemens Aktiengesellschaft

InventorsHelmut Markert, Klaus Kretzschmar, Michael Schreyer, Gu/ nter Mennig, Peter Braun, Oliver Eitel

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Abstract

In a process for producing a prepolymer epoxy resin mixture with oxazolidinone structures, a filler-containing thermally polymerizable reaction resin mixture of polyepoxy resin, consisting of a mixture of di- and multifunctional epoxy resins, and polyisocyanate resin, with a molar ratio of the epoxy groups to the isocyanate groups of >1, is fed to a continuously working reactor. With substituted imidazole as reaction accelerator, amounting to 0.5-2.5% of the polyepoxy resin, the reaction resin mixture is then reacted at temperatures up to 200.degree. C., with reactor temperature at 140.degree.-190.degree. C., and following that the extruded material is cooled down to a temperature of <50.degree. C. with the aid of a cooling device mounted at the outlet die of the reactor.

Claims17

Dependent claims

A process for producing an epoxyoxazolidinone prepolymer mixture, comprising the steps of:

feeding a filler-containing, thermally-polymerizable reaction resin component comprising a mixture of a polyepoxy resin, comprising a mixture of di- and polyfunctional epoxy resins, and a polyisocyanate, with a molar ratio of epoxide groups to isocyanate groups of >1, to a continuously working reactor;
reacting the reaction resin mixture at a reaction temperature of up to 200.degree. C., the reactor temperature being from 140.degree. to 190.degree. C., in the presence of a catalyst component comprising an inertly substituted imidazole as a catalyst, the catalyst being used in an amount of 0.5 to 2.5% by weight based on the polyepoxy resin;
and cooling extrudate emerging from an outlet die of the reactor to a temperature of <50.degree. C. by means of a cooling device located at the outlet die of the reactor.

Dependencies are inferred from the claim text.