低模量脱酮肟型有机硅密封胶的研制

Preparation of Low Modulus Deketoxime Silicone Rubber

采用α,ω-二羟基聚二甲基硅氧烷(107硅橡胶)、纳米碳酸钙、二甲基硅油、扩链剂、处理剂等制得低模量脱酮肟型单组分有机硅密封胶。探讨了107硅橡胶黏度、扩链剂和处理剂用量对密封胶性能的影响。结果表明,随着107硅橡胶黏度从10 000 mPa·s增大到80 000 mPa·s,密封胶-20℃和23℃时的拉伸模量分别从0.85 MPa和0.7 MPa降至0.5 MPa和0.3 MPa,邵尔A硬度从40度降至30度,拉断伸长率从304%升至524%;随着扩链剂用量从0增加到2份,密封胶的表干时间从14 min延长至35 min,硫化深度从2.12 mm减少至1.5 mm,拉伸强度从1.42 MPa先降至1.15 MPa后升至1.3 MPa,拉断伸长率从367%升至768%,邵尔A硬度从33度降至20度;随着处理剂用量从0增加到2份,密封胶23℃和-20℃时的拉伸模量分别从0.62 MPa和0.81 MPa降至0.23 MPa和0.46 MPa,拉伸强度从0.96 MPa降至0.75 MPa,拉断伸长率从375%升至549%,邵尔A硬度从35度降至18度,硫化深度从2.2 mm减至1.76 mm;采用1~5份处理剂制得的有机硅密封胶在90℃环境中贮存24 h后,外观细腻,硫化情况正常;较佳配方为:107硅橡胶黏度优选50 000 mPa·s,扩链剂用量0.5份,处理剂用量1份,此配方制得的密封胶拉伸强度为0.92 MPa,拉断伸长率为782%,23℃和-20℃时的拉伸模量分别为0.37 MPa和0.54 MPa,邵尔A硬度为19度。

The low modulus ketoxime one-component silicone sealant has been prepared byα,ω-dihydroxy polydimethylsiloxane(107 silicone rubber),nano calcium carbonate,dimethyl silicone oil,chain extender,and treatment agent.The effects of the viscosity,chain extender and treatment agent of 107 silicone rubber on the performance of the sealant has been discussed.The results show that as the viscosity of 107 silicone rubber increases from 10000 mPa·s to 80000 mPa·s,the tensile modulus of the sealant at-20℃decreases from 0.85 MPa to 0.5 MPa and the tensile modulus of the sealant at 23℃decreases from 0.7 MPa,to 0.3 MPa,Shore hardness decreases from 40 A to 30 A,and the elongation at break increases from 304%to 524%;as the amount of chain extender increases from 0 to 2,the curing time of the sealant increases from 14 min to 35 min,the vulcanization depth reduces from 2.12 mm to 1.5 mm,the tensile strength reduces from 1.42 MPa to 1.15 MPa and then increases to 1.3 MPa,the elongation at break increases from 367%to 768%,and the Shore hardness drops from 33 A to 20 A.When the treatment agent increased from 0 to 2 phr,the tensile modulus of the sealant at 23℃decreases from 0.62 MPa to 0.23 MPa,the tensile modulus of the sealant at-20℃decreases from 0.81 MPa to 0.46 MPa,and the tensile strength decreases from 0.96 MPa to 0.75 MPa,the elongation at break increases from 375%to 549%,the Shore hardness decreases from 35 A to 18 A,and the vulcanization depth decreases from 2.2 mm to 1.76 mm.The silicone sealant(treated with 1~5 phr of treatment agent)is stored in 90℃for 24 hours,has good appearance and normal vulcanization.The preferred formula is as followings:107 silicone rubber has a viscosity of 50000 mPa·s,0.5 phr of chain extender,and 1 phr of treatment agent.The sealant prepared has tensile strength of 0.92 MPa,the elongation at break of 782%,and the tensile modulus(at 23℃and-20℃)of 0.37 MPa and 0.54 MPa,respectively,and Shore hardness of 19 A.