| 摘要 |
1357380 Thermal cracking of perfluorocarbon polymers FARBWERKE HOECHST AG 24 June 1971 [24 June 1970] 29600/71 Heading C3P Fluorocarbon waxes are prepared by the thermal cracking of a perfluorocarbon polymer at an elevated temperature and at a sum of the partial pressure of the degradation products in the range from 5 to 100 atmospheres gauge. A pressure may be established before the beginning of the thermal cracking by means of an inert gas. A fluorocarbon pyrolysis catalyst may be present. In the examples polytetrafluoroethylene scrap or a tetrafluoroethylene/hexafluoropropylene copolymer is thermally cracked in a high pressure autoclave or a pressure tube in the presence of nitrogen, potassium nitrate and sodium nitrite. The crude wax is separated by fractional vacuum distillation, solvent vapour distillation or fractional crystallization. |
