GB821897A - Improvements in or relating to method of and apparatus for moulding plastic facings on building blocks - Google Patents

Abstract

821,897. Moulding plastic facings to concrete building blocks. UNITED STATES RUBBER CO. June 20, 1957 [June 21, 1956], No. 19432/57. Class 87(2). [Also in Group X] In a continuous method for providing building blocks with glass fibre-reinforced resin facings, predetermined quantities of the resin and glass fibre are placed in a series of metal moulds moving along a closed path and the preheated blocks deposited into the moulds with the surfaces to be faced in contact with the resin, while simultaneously applying pressure to the block and heating the resin. At the rear end of the conveyer 20 which comprises a series of shallow rectangular moulds 26, a thin film or shell-coat of resin of the same general chemical type as that of the main facing is placed on the bottom of each mould. The moulds, when in the lower reach of the conveyer, pass through an open ended oven 93 to gel the resin film and they are then cooled by a fan 95 to prevent setting of the resin. The liquid resin for the main facing, e.g. polyester resin, epoxy resin, or polyvinyl chloride plastisol, and compounding ingredients are agitated in container 57, sucked into dispenser 53, and then ejected into the moulds 26. Pre-cut sheets 3 of glass fibre mat and preheated blocks 1 are also loaded into the moulds 26. The moulds then pass over two heating platens 70, 71, the first of which is disposed under press platen 80a. The second platen 71 is about three times the length of the platen 70, sufficient to bring about final setting of the resin. When a block comes into the correct position beneath the press platen 80a, control means, automatically stop the conveyer and cause the press platen to be brought down onto the block with sufficient pressure to mould the facing to the block. Specification 497.175 [Group IV] is referred to.