Expanded phenolic resin panel with impermeable skin - produced by expanding resin compsn. contg. hydrophilic material and then polycondensing

摘要

A panel comprises an expanded phenolic resin with closed cells and a divided hydrophilic material. The resin also contains fillers. The panel has an impermeable phenolic resin skin and pref. also a polycondensed phenolic resin outer layer. The hydrophilic material is pref. plaster, gypsum or similar. The fillers pref. comprise beads or microspheres of glass or expanded polystyrene or clay. The panel is produced by first expanding the compsn. and then polycondensing. By dissociating expansion and polycondensation, maximum expansion is achieved before hardening, i.e. complete filling of the mould is achieved, with the result that closed cells and a homogeneous, impermeable skin are formed.