MAKING COATED PLASTER CONSTRUCTIONAL UNITS

摘要

1466773 Coating gypsum J N LOWE and B C GREBE 23 May 1975 [7 Aug 1974] 34832/74 Heading B5A [Also in Division B2] A constructional unit such as a planar or L- shaped panel comprising calcined gypsum, is moulded as described in the copending Specification 1,466,772. Before or after removal from the mould but when self-supporting and warm and moist, the surface of the unit receives a quantity of liquid synthetic resin which is drawn into the pores of the unit by capillary action to provide a water-resistant seal. The resin comprises a polyurethane, or a resin based or soya bean oil.