Foam packing material with surface layer of e.g. paper - has improved transverse rigidity, is offset printable and cheaper to produce

摘要

A packing material with =1 intermediate layer of foamed resin, has the foam layer comprising a deformed web of polystyrene foam, the peaks of the profile of which are covered on one or both sides with a surfacing layer. The foamed layer may be a polystyrene foamed web machined into an undulating contour in the longitudinal direction, with the crests of the waves bonded to a covering layer on each side. The prodn. process may commence with a prefoamed polystyrene foamed web which is raised to the plasticising temp. to cause secondary foaming, in a heated bath of hot water. Whilst at the plasticising temp. it is deformed and then cooled, to be clad on one or both surfaces on the profile peaks. The laminate has the high degree of transverse rigidity missing from conventional packing materials of this type. It is resistant to humidity, requires the min. of raw materials for its prodn. and it can be offset printed.