大型铸钢件用酯硬化碱性酚醛树脂粘结剂系统的开发研究

Development and Research on the Ester-Cured Alkaline Phenolic Binder System for Large Steel Castings

碱性酚醛树脂砂系一种环境友好铸造粘结剂,在我国高质量铸钢件的生产中得到了成功应用。但是,将其应用于大型铸钢件,经常遇到两个关键问题:一是在起模时游离甲醛释放量多,严重污染作业环境;二是型芯砂的可使用时间短,不能满足大型铸钢件造型制芯工艺的需要。本研究通过优化树脂的合成工艺和添加环保型降醛剂,使起模时型芯的游离甲醛释放量降低至0.25 mg/m3以下,较好地解决了酯硬化碱性酚醛树脂砂系统的环保问题。另外,通过开发特慢固化剂,可使型芯砂的可使用时间延长到120 min,完全满足大型铸钢件造型制芯的生产需要。

The ester-cured alkaline phenolic binder systems is a more environmental friendly foundry binder, which has been successfully applied to making high grades of steel castings in China. But when applied to a large steel casting, there are two key problems to be solved： （1） too much free formaldehyde emission usually occurs during the stripping of pattern, thus leading to serious environmental pollution; （2） the bench life is too short to meet the requirements of moulding and core making processes for large steel castings. A large number of trials show that the free formaldehyde emissions during the stripping can be reduced to below 0.25 mg/m^3 by optimizing the synthesis process and adding environment-friendly aldehyde reduction agent, thus the environmental problems of ester-cured alkaline phenolic resin bonded sand were solved. In addition, a special slow-curing agent for alkaline phenolic resin has been developed, the bench life of which can be extended up to 120 min, meeting the production requirements of moulding and core making for large steel castings.