弹性条缝筛网用聚氨酯弹性体的研制

采用预聚法常压浇注制备煤矿用聚氨酯筛网，考察了聚醚多元醇、甲苯二异氰酸酯异构体种类、预聚体的NCO质量分数、扩链反应温度、后熟化温度及时间等条件对制筛网用的浇注型聚氨酯弹性体体系操作性能及物理性能的影响。实验表明，采用聚四氢呋喃二醇与聚氧化丙烯二醇的混合二醇(质量比为80：20)，制得的预聚体NCO质量分数控制在4．5％左右；再以MOCA和一种三官能度扩链剂的混合扩链剂进行扩链，制得的浇注型聚氨酯弹性体满足洗煤用筛网的性能要求。

The Study of Polyurethane Elastomers for Mesh Screens

Polyurethane elastomers for coal-washing screens were prepared by casting method. The factors affecting the operation time (pot life) and mechanical properties of the elastomer were discussed as follows: polyol varieties, free NCO content in prepolymer, chain-extending temperature,post-curing temperature and time .The results show that the free NCO content in prepolymer based on blend polyols of PTMEG/PPG (at weight ratio of 80/20) and toluene diisocyanate can be controlled at 4.5%, then extended with blend chain-extender, the properties of the polyurethane elastomers meet the requirement of coal-washing screens.