铸造用CO2硬化酚醛树脂粘结剂系统的优化

铸造用CO2硬化碱性酚醛树脂粘结剂是一种新型的粘结剂系统，由一种特殊合成的碱性酚醛树脂、碱、硼砂和硅烷等组分组成。基于此，以抗压强度为主要考察指标，通过对粘结剂中酚醛树脂、碱、硼砂和硅烷加入量进行正交试验，得出优化的配比为酚醛树脂∶KOH∶硼砂∶硅烷=100∶45∶16∶1，组成了稳定的粘结剂系统，吹入CO2气体硬化后系统得到了较高强度。KOH、硼砂对强度的影响比较显著。在粘结剂中按一定比例分别加入乙醇、丙酮、甘油等物质，并进行粘结剂强度试验，这些材料对粘结剂强度能有一定促进作用，其中两种有机活性助剂，可以明显改善粘结强度，加入量分别为粘结剂量的5%、15%。通过优化，粘结剂初强度可达1.5MPa以上，终强度值可达3.7 MPa以上。最后通过扫描电镜对砂样粘结桥断口形貌分析，证明有机活性助剂在粘结剂系统中主要起络合、交联作用。

Optimization of CO2-Cured Phenol-formaldehyde Resin Binder Used in Foundry

The CO2-cured alkaline phenol-aldehyde resin binder used in foundry is a new kind of binder system which is composed of specially synthesized alkaline phenol-aldehyde resin, alkali, borax and silane. According to the affection on the compressive strength of binder, the optimum results are achieved by the experiments of orthogonal design about the amounts of alkaline phenol-aldehyde resin, alkali, borax and silane to form a steady binder system with high compressive strength. The proportion of the above components is the alkaline phenol-aldehyde resin∶KOH∶Borax∶KH-550=100∶45∶16∶1, and the influence of KOH, borax to the compressive strength of binder is more remarkable. A few kind of materials such as alcohol, acetone and glycerin are added into the binder separately to test the influence of each one on the compressive strength of binder. It is found that two kinds of organic active agents with addition 5%, 15% to the binder can improve the strength of binder obviously. At last the higher initial strength above 1.5 MPa and final strength above 3.7 MPa can be achieved by optimization of the components and the behavior of bonding bridge fracture is analyzed by using scanning electron microscope. The organic active agents are believed to play an important role in cross-linking of resin and have great effect on the strength of binder.