异氰酸酯对聚硫密封剂施工性能的影响

Effect of Isocyanates on the Process Performance of Polysulfide Sealant

随着现代飞行器设计水平的不断提升,飞机结构的复杂化,导致密封剂的施工周期需求不断延长。为了满足这个需求,设计了一种施工期可控的聚硫密封剂。通过在聚硫密封剂的基膏中加入一定量的异氰酸酯,利用异氰酸酯和聚硫密封剂的活性巯基端基与水分的竞争反应,降低密封剂硫化反应的速度。根据所需施工期的时间长短适当调节聚硫密封剂硫化膏中促进剂的种类和比例。最终使密封剂的活性期延长至一周左右,满足了长时间装配的要求。

With the continuous improvement of the design level of modern aircraft and the complexity of aircraft structures,the demand for sealants construction period continues to be extended.In order to meet this requirement,a polysulfide sealant with controllable construction period is designed.By adding a certain amount of isocyanate to the base paste of polysulfide sealant,the competitive reaction between isocyanate and the active thiol end group of polysulfide sealant and water is utilized to reduce the curing reaction speed of sealant.By adjusting the type and proportion of accelerator in the vulcanizing agent of polysulfide sealant appropriately according to the length of required construction period,finally,the active period of sealant is extended to about one week to meet the requirements of long-term assembly.