Improvements in or relating to the construction of floor blocks, wall panels, hollow wall blocks, tiles, and the like

摘要

A floor block, wall panel, hollow wall block, tile, or the like consists of two outer layers bonded to an intermediate layer of lower density, each of the layers being separately moulded by heat and pressure from a mixture of wood waste and natural or synthetic resin. The blocks may be made by first moulding the two outer layers, coating one face of each with a synthetic resin adhesive, applying the wood-waste resin mixture to the coated face of one outer layer, applying the coated face of the other outer layer to the mixture, and subjecting the composite block so formed to the heat and pressure sufficient for production of the required lower density of the inner layer. The intermediate layer may be cut away in order to reduce the density of the block, or may be cored for the reception of pipes or wires. Examples of the mixtures moulded are a mixture of urea-formaldehyde resin syrup and coarse wood shavings or chips, of 15 per cent resin content, containing ammonium chloride for acceleration of the polymerization and hardening of the resin, and the product obtained by drying a mixture of 3 parts of sawdust, small wood shavings or wood chips up to 1in. in length and 1 part of a 60 per cent emulsion of phenol-formaldehyde resin in water, and, if desired, phosphoric acid for hardening of the resin.