Manufacture of thin pressed glass fibre reinforced plasterboard - entails making sandwich using plaster and fibre mixture under pressure

摘要

The process produces a thin plaster based board, by first depositing a layer of plaster on a bed, covering it with a glass fibre fabric (15), and then placing a second plaster layer. Plaster mixed with water to 'casting' quality is used the used, the resulting sandwich some 1 mm thick then being subjected to a pressure designed to ensure that the glass fibres penetrate the plaster layers. The unit weight of the glass fibre is not less than 200 grammes per sq. m and the pressure applied exceeds atmospheric. A relative pressure of 0.5 to 12 bars may be applied to the plaster for 5 to 60 min. between mixing and deposition and during mixing to obtain higher densities, also being used to propel (11a,11b) the material into the mould. A setting retarder may be used before deposition with an accelerator applied to the casting.