| 摘要 |
Known sheet sealing material from which gaskets can be cut for sealing against an agressive chemical such as sulphuric acid comprises a sintered PTFE resin in which is dispersed an inert inorganic filler (eg ground quartz, against sulphuric acid) substantially all of which is of particle size less than 106 mu m, and in particular less than 75 mu m, most of it passing 53 mu m. According to the invention, the size distribution of filler is such that while substantially all of it remains of particle size less than 106 mu m, 17.5 to 35% by weight is of particle size greater than 53 mu m. Preferably at least 5% by weight is of particle size greater than 75 mu m. |
