铸造用CO_2硬化聚乙烯醇粘结剂促硬剂的研究

A Hardening Accelerator for CO_2-Cured Polyvinyl Alcohol Binder Used in Foundry

研究了CO2硬化聚乙烯醇粘结剂的促硬剂,是由Ca(OH)2、硅酸盐水泥及一种水硬性材料复合混制而成,原料来源广泛,价格低廉。加入促硬剂后,缩短硬化时间,大幅度提高粘结剂的粘结强度,并加入交联剂、偶联剂进一步提高粘结剂工艺强度。试验中通过正交试验优化各组分的添加比例,并对混合后型砂的可使用时间、吹制砂芯的存放性、溃散性和发气性等工艺性能进行了试验,并对性能增强机理进行简要的分析。

A hardening accelerator for CO2-cured polyvinyl alcohol binder used in foundry has been developed. It is a compound of Ca （OH）2, 425# cement and a kind of hydraulicity material, which are very cheap and could be purchased easily. The hardening accelerator can shorten the hardening time and increase the sensitivity of the binder. The sensitivity of the binder can be increased further by adding crosslinker and coupling agent. The proportion of each part in the hardening accelerator has been optimized by means of orthogonal test method, and then the properties of the sands mixed with binder, such as working time, and preservation, collapsibility and gas evolution of the core, have been compared between the samples with and without hardening accelerator. At last, the mechanism of reaction between the hardening accelerator and the binder was analyzed.