SOFT SEALING MATERIAL

摘要

There is disclosed a composition for a soft (non-metal) sealing material having the following percentage composition based on the overall composition: from 4 to 9 wt.% of fibrillated polyaramide fibers; less than 60 wt.% of powder graphite having a carbon content of 90 to 92 wt.% and such particle size distribution that at least 85% of all particles are in the size range of 10 νm to 50 νm; about 30 wt.% of mineral fillers represented by a combination of microsilica having a SiO2 content between 90 and 95 wt.%, a specific surface area according to BET method of 15 to 25 m2/g and such particle size distribution that at least 90 wt.% of all particles are in the particle size range under 5 νm, and of an active mineral filler having a SiO¿2? content of at least 98 wt.%, a specific surface area according to BET method of 100 to 120 m?2¿/g and such particle size distribution that at least 90 wt.% of all particles are in the particle size range of 5 νm to 50 νm, the ratio of microsilica to the mineral filler being such that the value of the total specific surface area according to BET method is between 45 and 55 m2/g; and, optionally, friction agents for enhancing the friction between graphite particles and, optionally, biosoluble mineral fillers; about 12 wt.% of elastomeric binders; up to 2 wt.% of a vulcanization system in paste form containing zinc dibenzyldithiocarbamate (ZBEC) or zinc 2-ethylhexyldithiophosphate (ZDT) as vulcanization accelerants; and usual auxiliary substances in usual amounts.The material is produced according to a process, which is also one of the objects of the present invention, and is used for the manufacture of gaskets for technical and industrial applications.