| 摘要 |
PURPOSE:To collapse sand by mechanical impact alone without requiring heating treatment after casting by coating a compsn. consisting of a prescribed ratio of a solid phenolic resin, phosphate, dicyandiamide, lubricant, etc. on silica sand. CONSTITUTION:A compsn. consisting of 1-3pts.wt. solid phenolic resin, 0.05- 1.5pts.wt. phosphate, 0.05-1.5pts.wt. dicyandiamide, 0.05-0.3pts.wt. lubricant and if necessary hexamethylenetetramine is prepd. The compsn. is coated on 100pts.wt. silica sand. The resulting resin coated sand for casting is collapsed by mechanical impact alone without heating treatment after casting. |
