External thermal insulation of polyurethane foam - with complementary reinforcement and paints, using spray generation to foams of 30-80 KG per M3

摘要

Thermal insulation system for external application to vertical surfaces of buildings etc. involves superposition of a layer (1) of polyurethane foam of 30-80 kg/m3 density, applied by spray lay-up; a layer (2) of suitable adhesive; inserts of perforated angle section of stainless steel to support and protect corners, covered with woven alkali-resistant glass cloth also impregnated with adhesive of sufficient quantity and elasticity to accommodate internal differential thermal expansion strains; a coat of white paint to block impinging UV radiation; plus undercoat and topcoat paints of similar shades, coloured in bulk. Where the insulation is at a door or window surround, superficial water lip profiles of stainless steel may also be mounted. Horizontal surfaces, e.g. roofs, are insulated by spray coating the foam layer on to a film of water stop material and covering the foam with a protective sheet and a dressing of sand etc. Example materials include use of a composite primer paint of aq. cement modified vinyl acetate copolymer dispersion; perforated stainless steel profile 6 mm thick; glass netting of 4mm aquare mesh; 150 g/m2, with a strength of 30 daN/cm. The UV screen paint was a vinyl acetate/vinyl ester copolymer dispersion including finely divided rutile (TiO2) and Ca carbonate fillers. The external undercoat and top coat paints were based on similar resins. Pref. the systems are applied under local ambient conditions of 5-30 deg.C.