COATED MASONRY BUILDING UNITS

摘要

1386194 Faced Masonry blocks BURNS & RUSSELL CO OF BALTIMORE CITY 9 Feb 1973 [15 Nov 1972] 6601/73 Heading B5A [Also in Divisions B2 C1 and C3] A masonry block 12 is provided with an integral facing 13 formed from a composition comprising a thermosetting resin, at least 50% by wt. of sand which has been treated with 0À1- 2% of its weight of an alkylene substituted silane or siloxane and, at least 3% by weight of magnesium hydroxide. The facing is applied to the block by introducing the composition into a preheated mould 10, placing the block 12 onto the composition and curing the resin. The composition may be applied in two layers, the first layer having a ratio of sand to other components of 0À5-1 : 1 by weight and the second layer having a ratio of 2-3À5 : 1 and being present in an amount three to four times that of the first layer. At least the first layer is sprayed into the mould, mixing being achieved by interaction of the jets of the components from a multi-nozzle spray gun (Fig. 1). The second layer may also be poured into the mould as a pre-mixed slurry. The sand may comprise round particles of 1/ 16 -2 mm. and be present in two size classifications, one being 30-70 mesh and the other being a smaller 100-325 mesh. The silane or siloxane may be applied to the sand as a vapour or as a solution in a solvent such as benzene or toluene. The silane or siloxane may have the formula where R includes an alkylene group, X is chlorine, bromine, oxyaryl, oxyalkyl, or amino group, and x is a number from 1 to 3. The resin may comprise a polyester and/or an acrylic. Many examples of silanes, siloxanes, resins, cross-linking solvents, catalysts, oniumgroup containing clays as suspending agents fillers are given. The composition may also include antimony trioxide, chlorinated paraffins and tricresyl phosphate. The block may be “-¢ inch thick and may be made from cinders, slag, haydite, concrete, clay, sand, gravel, cement-asbestos or epoxy aerated concrete. The resin may be cured at 250-350‹ F. for 8-25 minutes. A plurality of blocks may be coated in an apparatus comprising a conveyer 21 for feeding a plurality of moulds 10 past a bank of strip or lamp heaters 25 which pre-heat the moulds to a temperature of 180-240‹ F., a pair of spray guns 27, 28 mounted on carriages for oscillation or reciprocation over the moulds 10 by piston/cylinders 29, 30 to apply the coating layers, a conveyer (40) for feeding the blocks 10 to the moulds (Fig. 6B) and a chain conveyer 53, 54 for carrying the blocks over gas burners or dielectric coils to cure the facing composition. The moulds 10 may be made of stainless steel, or steel lined with glass enamel, frit or porcelain. Each spray gun (Figs. 1, 2) may comprise three converging nozzles (2-4) through which the resin components may be fed and a pipe 5 through which an air suspension of sand is fed.