Dry curing agent coated casting sand mold and preparation method thereof

By combining modified furan resin with acidic dry powder curing agent, the problems of easy volatility and humidity sensitivity of liquid acidic curing agent are solved, achieving uniform curing and high-strength molding of casting sand mold, and reducing odor and environmental impact.

CN122441889APending Publication Date: 2026-07-24JINGCI (BEIJING) NEW MATERIAL TECH CO LTD
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Patent Information

Application Number
CN202610802104.7
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2026-06-04
Publication Date
2026-07-24

AI Technical Summary

Technical Problem

The existing furan resin sand mold preparation process suffers from the following problems: the liquid acid curing agent is volatile, sensitive to environmental humidity, and has insufficient uniformity in mixing with sand particles and resin. In addition, traditional furan resin has a high free formaldehyde content and odor, which leads to unstable curing uniformity and molding strength of the sand mold.

Method used

Cashew phenol is subjected to a nucleophilic substitution reaction with 2,5-dibromofuran, followed by graft polymerization with sugar alcohol to form an environmentally friendly modified furan resin. This modified furan resin is then compounded with dicalcium phosphate, ammonium p-toluenesulfonate, and ammonium oxalate to form an acidic dry powder curing agent with zero free acid content. This agent is then mixed with refractory aggregates or raw sand through high-speed dry mixing and coating, and finally the environmentally friendly modified furan resin is added for molding and natural curing.

Benefits of technology

It improves the hardening uniformity, molding stability and compressive strength of casting sand molds, reduces the risk of harmful defects such as acid seepage and sulfur seepage caused by free acid, and reduces odor and environmental impact.

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Abstract

The invention belongs to a preparation method of a casting sand mold, and aims to solve the problems that in an existing furan resin sand mold preparation process, a liquid acid curing agent is volatile, sensitive to environment humidity and poor in mixing uniformity with sand and resin; the invention provides a dry-state curing agent film-coated casting sand mold and a preparation method thereof, and aims to solve the technical problems of insufficient sand mold curing uniformity and molding strength stability caused by high free formaldehyde content and odor of traditional furan resin in the prior art in order to provide the dry-state curing agent film-coated casting sand mold and the preparation method thereof, which comprises the following steps: preparing environment-friendly modified furan resin; calcium hydrophosphate, ammonium p-toluenesulfonate and ammonium oxalate are compounded into an acidic dry powdery curing agent with the free acid content being 0; adding the curing agent into refractory aggregate or crude sand, and carrying out high-speed dry-state mixing and laminating, so as to obtain curing agent dry-state laminated aggregate; and adding environment-friendly modified furan resin, stirring, mixing, molding, and naturally hardening and molding to obtain the casting sand mold. The molding stability and compressive strength of a cast sand mold can be improved, and the influence of free formaldehyde, free acid and odor is reduced.
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