| 摘要 |
PURPOSE:To form a sand mold having excellent mold strength and regeneratability of molding sand after use in the stage of forming a sand mold for casting by mixing a water soluble polymer contg. a specific carboxylic group and a metallic compd. with molding sand and kneading the same with water. CONSTITUTION:A sand mold for casting is formed by adding 0.2-20pts.wt. a water-soluble polymer contg. a carboxylic group of acrylic acid and methacrylic acid having >=1,000mol.wt., 0.01-15pts.wt. oxide or hydroxide of bivalent or trivalent metal such as Mg, Al, Ca, Zn, Fe or the like, more particularly MgO having 220-320Angstrom size in [200] direction of the crystal determined by an X-ray diffraction method and 0.5-20pts.wt. water, kneading the mixture and molding the same into a sand mold. The equiv. number of the metallic compd./the equiv. number of the carboxylic group in the water soluble polymer is made 0.15-1.4 and the content of the water/the content of the water-soluble polymer is made to 0.3-1.4. |
