Method of fusion bonding low density thermoplastic bodies

Abstract From the Canadian patent

19-, Abstract of the Disclosure, A method for contact fusion bonding of compressible, low density thermoplastic parts is disclosed, which comprises essentially: (a) fluidizing only a surface film on opposed mateable margins of the thermoplastic parts by precompressing the margins against a transversely stationary heated platen located therebetween and, prior to fluidization continuing such, contact to promote such fluidization by thermal conductivity and make heat settable a limited predetermined, nonmelted subsurface layer of said mateable margins; and (b) within a time period during which said surface films remain fluid, withdraw said platen from between said opposed margins with minimal …