| 摘要 |
PROBLEM TO BE SOLVED: To accelerate the hardening speed and to reduce the odor at the casting time by using binder composition containing acid hardenable resin and a specified hardening promoter, hardening agent composed of one or more kinds selected from groups of sulfonate compound and sufric acid and a specific ratio or higher of sulfur content brought about a phenol sulfonic acid and refractoriness granular material. SOLUTION: The binder composition containing the hardening promoter shown in the formula (in the formula, X1 and X2 show anyone of H, CH3 or C2H5), is used. The hardening agent containing >=50% sulfur content brought about the phenol sulfonic acid, is used. Desirably, the hardening agent is composed of the phenol sulfonic acid or the phenol sulfonic acid and the sulfric acid and the acid hardenable resin is one or more kinds selected from furfuryl alcohol, urea/formaldehyde polycondensation material, phenol/formaldehyde polycondensation material or fulfuryl alcohol/formaldehyde polycondensation material, and the hardening promoter is 7,5-bishydroxy methylfuran.
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