一种新型水溶性金属注射成形用粘结剂的研制

论文在抽提MI M粘结剂中水溶性组分及高分子组元功能的基础上,通过参数计算、溶解试验确定了水溶性组分的品种、PEG的分子量分布,进而结合混合试验以及扫描电镜测试确定了水溶性MI M粘结剂中的高分子组元和整个粘结剂配方。结果表明,PEG是一种合适的水溶性组分,恰当的分子量分布,即10%PEG600+30%PEG1000+60%PEG1500的混合配方可以满足MI M工艺对其热收缩率的要求;PEG-POM具有热力学相容性,其混合物流动性、冷却强度好但水溶性差;PMMA分子量对PMMA-PEG的混合性具有决定性的作用,在PMMA分子量适中(M=(40·7~98·4)×104)时,PEG-PMMA混合物相容性、冷却强度和水溶性都较好,但流动性稍差;当PEG-POM-PMMA三者以75∶23∶2配比组成三元系时,它兼备了PEG-POM和PEG-PMMA二元体系的优点,总体效果最好。为了增加粘结剂水溶性组分PEG的热稳定性、改善组分间的相容性、降低黏度和增加粘结剂对粉末的润湿性,粘结剂需要配以适量抗氧剂BHT、增塑剂DOP和表面活性剂。最终确定粘结剂适宜配方为:PEG72%,POM23%,PMMA2%,SA2%,DOP1%,BHT0·01%。

A novel water soluble binder for MIM

In the paper,the function of water-soluble ingredients and polymer components of binder during metal injection molding (MIM) was extracted, and the component,molecular weight distribution of polymer and the batch formula were determined by solubility parameter calculation,solution tests,mixing test and SEM analysis.The results indicate that PEG is a suitable water soluble component for MIM binder,and is able to satisfy the thermal shrinkage ratio of MIM technology when the mixture,made up with 10%PEG600,30%PEG1000 and 60%PEG1500,is used.The results also show that PEG-POM is a thermodynamic compatibility system and the mixture has good flowability, cool strength but bad water solubility,while PEG-PMMA is a technical compatibility system and has excellent water dissolubility but bad flowability. Thus the three ingredient mixture of 75% PEG,23%POM and 2%PMMA behaves the both merits of PEG-POM and PEG-PMMA. To improve the compatibility of inter-ingredient, heat endurance and wettability of binder,BHT,DOP and surfactant SA were used as additives. The final suitable formula of the water soluble MIM binder is as follows:PEG 72%,POM 23%,PMMA 2%,SA 2%,DOP 1%,BHT 0.01%.