Producing relatively non inflammable - insulating boards from foamed polystyrene

摘要

High-strength boards are made, e.g. for use in building construction, by wetting pre-foamed particulate polystyrene with a preliminary precondensate of urea formaldehyde and then with a mixture of this and a filler material. This is subjected to short bursts of steam under pressure in a mould. The filler pref. consists of asbestos, asbestos fibres, quartz sand or perlite.