1303709 Foundry mould compositions ASHLAND OIL Inc 10 March 1970 [10 March 1969] 11515/70 Headings C3N and C3R A curable foundry mix comprises a foundry aggregate and a curable binder comprising at least one phenolic resin which is substantially free of water and at least one polyisocyanate together with a fatty acid in an amount up to 5% based on the weight of the foundry aggregate. The fatty acid may be a saturated or unsaturated monocarboxylic acid (C 4 -C 26 ) or a polymerized fatty acid, e.g. dimers and trimers of unsaturated fatty acids. Numerous examples of such acids are given in the specific examples. A comparative Example (II) refers to the use of CF 3 COOH. The phenolic resin may be a resole or novolac resin whilst the polyisocyanate may be any of the conventional aliphatic, cycloaliphatic or aromatic polyisocyanates. The phenolic resin is preferably the condensation product of a phenol having the general formula wherein A, B and C are hydrogen, hydrocarbon, oxyhydrocarbon or halogen with an aldehyde RSP1/SPCHO, wherein RSP1/SP is hydrogen or hydrocarbon (C 1 -C 8 ). The foundry aggregate is preferably sand and the fatty acid may be mixed simultaneously or separately with the sand or alternatively the fatty acid may be mixed with the phenolic resin or with the isocyanate prior to mixing with sand. The resulting mix is introduced into a mould and cured by the use of a tertiary amine gas, e.g. triethylamine. The foundry mix of the invention has merit in that it does not stick to the metal pattern. Optional ingredients of the mix include iron oxide, ground flax fibres, wood cereals, pitch and refractory flours. The invention is also directed to a binder composition per se, suitable for use in the foundry mix, comprising a non-aqueous phenolic resin having the general formula in which R represents a hydrogen atom or a substituent meta to the hydroxyl group of the phenol, m and n are numbers, the sum of which is at least 2, and the ratio of m to n is at least 1, and X represents a hydrogen or a methylol group, the molar ratio of the said methylol to hydrogen end-groups being at least 1; the hardener comprising a liquid polyisocyanate and the curing agent comprising a tertiary amine. The polyisocyanate may be present in an amount 10-500 weight percentage based on the weight of the phenolic resin and may be any of the conventional aliphatic, cycloaliphatic or aromatic polyisocyanates, preferably having 2-5 isocyanate groups, e.g. diphenyl methane diisocyanate. A particularly suitable tertiary amine is trimethylamine and this may be present in an amount 0À01-5% by volume of an air or nitrogen gas stream.
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