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

US6225377A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Helmut Markert · Nuremberg, DE
• Peter Donner · Espoo, FI
• Klaus Kretzschmar · Erlangen, DE
• Klaus Muller · Tamm, DE
• Michael Schreyer · Weisendorf, DE

Key dates

• Filing date: May 9, 1995
• Grant date: May 1, 2001
• Expiry date: May 9, 2015

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L2924/0002
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

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.degree. 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.