Formula Development And Process Verification Of Environmental Protection Insulation Gas Sealing Material

This paper studies the formulation development and process validation of a kind of environmental protection insulating gas sealing material used in power industry.Brominated butyl rubber 2244 was used as matrix material to overcome the inherent low resilience of butyl rubber.A formula of rubber sealing material with excellent physical and mechanical properties,low compression permanent deformation and high and low temperature resistance was developed.The bulk production process of butyl rubber O-ring was validated and developed through the magnification test of 20 kg grade rubber.The material formulation and processing technology with basic properties meeting the requirements of the project were prepared.The main contents of the study are as follows:Firstly,using butyl rubber 268,brominated butyl rubber 2244 and chlorinated butyl rubber1068 as matrix materials,the properties of raw rubber and vulcanizate were studied,taking into account the properties of compound and actual production efficiency.Carbon black reinforcing system,plasticizing system and vulcanizing system of butyl rubber were studied by using brominated butyl rubber 2244 as matrix material with the fastest vulcanizing speed.The relationship between different blending systems of butyl rubber and the properties of rubber compound was verified.Three groups of formulations with lower compression permanent deformation were screened out.It was determined that vulcanizing system was the core factor in the formulation of low compression permanent deformation butyl rubber seals.Finally,TMTD and MTT were used as vulcanization systems of brominated butyl rubber 2244.Then through the optimization of formulation and vulcanization process,it was shown that inorganic filler alumina,light calcium carbonate and talcum powder had adverse effects on the physical and mechanical properties and compression permanent deformation properties of vulcanizates.It was determined that the low compression permanent deformation butyl rubber seals were prepared by the combination of one-stage vulcanization and two-stage vulcanization.Finally,pilot scale-up test and batch trial production process of seals were developed with the optimum formulation.It was proved that the performance of 20 kg scale-up test compound was stable and the mixing process was the key factor affecting the subsequent processing and shaping of the compound.The first and second vulcanization processes had significant effects onthe compression permanent deformation property of the product.The frozen trimming process adopted in batch trial production had no effect on the properties of the compound.Curing time,curing temperature and pressure have significant effects on the shrinkage of rubber compound.The final product has been tested to meet the technical requirements of the project.