| 摘要 |
PCT No. PCT/GB80/00026 Sec. 371 Date: Oct. 27, 1980 Sec. 102e Date: Aug. 13, 1980 PCT Filed: Feb. 19, 1980 Pub. No. WO80/01767 Pub. Date: Sep. 4, 1980. A binder composition in aqueous solution, suitable for use in the production of foundry sand moulds and cores is obtained by mixing (i) an alkali metal silicate (ii) a substantially water soluble carbohydrate selected from monosaccharides, disaccharides, polysaccharides and derivatives thereof and (iii) urea. The composition may also contain an oxyanion such as a borate which is capable of forming a water soluble complex with the carbohydrate. The preferred carbohydrate is a stabilized starch hydrolysate whose reducing power has been removed by a process such as hydrogenation. Moulds and cores bonded using the composition may be hardened by injection of carbon dioxide gas, or a chemical hardening agent for the alkali metal silicate may be added to the sand. |
