WERKWIJZE TER BEREIDING VAN EEN BINDMIDDEL VOOR ELEK- TRISCHE ISOLATIE; GEVORMD VOORTBRENGSEL VERVAARDIGD MET ALDUS BEREID BINDMIDDEL.

摘要

1314546 Laminates SOC GENERALE DE CONSTRUCTIONS ELECTRIQUES ET MECANIQUES ALSTHOM 24 June 1970 [24 June 1969] 30748/70 Heading B5N [Also in Divisions C3 D1 and H1] Laminates, useful in electrical insulation, comprise layers of glass fabrics, asbestos fabrics and/or mica paper and a binder formed by mixing together at least 3 of the following 4 constituents: (I) an epoxy resin derived from bisphenol A having an epoxide equivalent of 174-195; (II) an epoxy novolac resin having epoxide equivalent of 175-182; (III) a novolac resin prepared from phenol with an organic acid catalyst and which contains 5-8 theoretical chain links; and (IV) an acid catalysed resin derived from 2 moles of resorcinol and 1 mole of formaldehyde. The ingredients are present so as to provide a ratio of OH groups (excluding any that may be present in the epoxy resins) to epoxy groups of 0À5-1À3. In a typical example (4) a flexible tape is formed from two glass fabrics with an intermediate layer of mica paper and impregnated with a composition according to the invention. The resultant laminated tape may be wound in several layers over conductors and cured, e.g. for 2 hours at 150‹ C.