Ceramic-filled fluoro-polymer compsn. for electrical substrates - with silanised filler present to give improved flow properties, e.g. into through-holes

摘要

Substrate material for electrical uses consists of (i) a fluoropolymer; and (ii) a silane-coated ceramic filler making up 45-50 vol.% of the total substrate material. Also claimed is the use of the above composite material (a) for filling holes in solid electrical substrates of (b) as an intermediate adhesive layer in multi-layer conductive plates. The fluoropolymer is pref. based on TFE, hexafluoropropylene and/or perfluoroalkylvinyl ethers. The ceramic filler is pref. of SiO2, esp. amorphous quartz powder of ave. size 10-15 microns with the hydrophobicising silane pref. being p-chloromethylphenyl trimethoxysilane, aminoethyl aminotrimethoxysilane or a mixt. of phenyltrimethoxysilane and aminoethyl aminopropyl trimethoxysilane. USE/ADVANTAGE - The material has better flow properties than the fluoropolymer material of US application 015191 (17th Feb. 1987) which contains greater amts. (above 50 vol.%) silanised ceramic filler (i.e. RO-2800 (RTM)). The improved flow properties are combined with good heat, mechanical and electrical properties and are demonstrated by the ability of two layers (54,56) of the material to flow into and completely fill the holes (52) of a solid structure (50) such as a Cu plate.