| 摘要 |
<p>1479365 Resin-impregnated fabric-paper laminates WESTINGHOUSE ELECTRIC CORP 12 Aug 1974 [15 Aug 1973] 35474/74 Heading B5N Laminate boards for printed circuits are made by bonding under heat and pressure an assembly of outer layers of epoxy resin-impregnated woven glass fabric with a resin-impregnated core of one or more sheets of water-laid cellulosic fibre paper therebetween. The components may be assembled as pre-pregs which have been made by immersing the fibrous layers in a resin bath, squeeze-drying and oven-curing to the B-stage. The core sheet(s) may be impregnated successively with phenolic and epoxy resins. The epoxy resin impregnants may be bisphenol or epoxy novolac resins, may be chlorinated or brominated, and may contain flame retardant additives and hardeners, e.g. dicyandiamide and (for the core) chlorendic anhydride. The paper sheets may be saturating papers of wood and/or cotton linters, preferably mixed hardwood and softwood fibres of overall average length 0À5-5 mm., which have been fibrillated by heating. A copper or sacrificial anodized aluminium foil may be included in the assembly. If the laminate is not so clad, the surfaces may contain a catalyst or may be treated with a catalyst-containing adhesive for the deposition of a printed circuit.</p> |
