Patent GB-1322496-A (GB)
Title: Coated articles
IPC: C08G18/80
Filed: 1969-08-18
Abstract: 1322496 Coated articles IMPERIAL CHEMICAL INDUSTRIES Ltd 28 July 1970 [18 Aug 1969] 41062/69 Heading B2E [Also in Division B5] Building blocks, bricks and tiles are coated on at least one surface with composition comprising a polyurethane resin which composition is derived from a component or components curable to form the said resin mixed with cement, sand and/or aggregate and water. The coated articles are produced by applying a composition comprising the above ingredients and thereafter curing the composition or allowing the composition to cure. The curable composition may be of the 1-pack, moisture-curing prepolymer type or a two-pack system in which an isocyanate group-containing component and a second component containing isocyanate-reactive groups (usually hydroxyl groups) are mixed just before use. The moisture-curable prepolymers are the isocyanate-ended reaction products of hydroxyl-ended polymers (e.g. hydroxyl-ended polyether, polyester or polyesteramide) with a diisocyanate. A preferred composition is a two-pack system comprising (1) an essentially diisocyanate product obtained by the reaction of a polyisocyanate of functionality at least 3 or a mixture thereof with other polyisocyanate and a monohydric alcohol of molecular weight at least 70 and (2) a reaction product of castor oil with a resin which is a rosinate of a metal selected from group 2a of the Periodic Table or a condensation product of rosin with (a) at least one polyhydric alcohol or (b) at least one polyhydric alchol and at least one optionally substituted phenol-formaldehyde resol resin, or (c) at least one polyhydric alcohol and at least one alpha, betaunsaturated dicarboxylic acid or the anhydride thereof. A particularly preferred composition is a two-pack system wherein (1) is obtained by the reaction of an oxyethylated isooctanol with the polyisocyanate composition prepared by the phosgenation of the mixed polyamine reaction products of formaldehyde and aniline in the presence of hydrochloric acid, and (2) is a reaction product of castor oil with the glycerol ester condensation products obtained from the reaction between rosin, glycerol and a diphenylol propane-formaldehyde resol resin. The composition may contain fillers, e.g. natural or coloured aggregates, clear or coloured glass, natural or coloured sand, chalk or alumina, and any wetting or emulsifying agent for cement. There may also be added coloured pastes based on inorganic or organic pigments dispersed in castor oil or polyester or polyether resins or in the reaction products of castor oil or other drying or non-drying oils with any hard resin formed by condensing at above 200‹C. (a) rosin, a low molecular weight polyhydric alcohol and a phenol-formaldehyde resol resin, (b) rosin, a low molecular weight polyhydric alcohol and maleic anhydride. Substances imparting fire-resistance and ultra-violet light absorbers may also be included. The blocks may be made from fired clay, concrete, foamed slag, or breeze block and may be of uniform structure or hollow. The coating composition may be applied with a trowel or preferably using a mould. The composition may either be injected into a mould and the block placed into the mould on top of the composition, or the block first placed in the mould and the composition applied to the block. The composition may be applied to heated blocks. The coating can be shaped to overlap the coated face(s) to give a minimum area of exposed mortar joints between adjacent articles.