| 摘要 |
PURPOSE:To obtain a binder which can improve the strength of a casting mold by adding a lubricant to a novolak type phenolic resin obtd. by the reaction, etc. of a phenol and formaldehyde when the softening point of said resin attains a specific value and adding further gamma-aminopropyl triethoxysilane thereto. CONSTITUTION:The lubricant is added and mixed to and with the novolak type phenolic resin obtd. by bringing the phenol and formaldehyde into reaction in the presence of an acidic catalyst by the conventional method, then executing dehydration concentration when the softening point of said resin attains 70-95 deg.C. The amt. of the lubricant to be added is preferably 0.5-5.0pts.wt. by 100pts.wt. the novolak type phenolic resin. The gamma-aminopropyl triethoxysilane or the hydrolyzate thereof is added thereto when the inside temp. attains 100-150 deg.C after the mixing. The binder obtd. in the above-mentioned manner can improve the adhesive strength of the shell mold to sand.
|
