| 摘要 |
<p>In a process for the manufacture of fluorocarbon waxes by the degradation of polytetrafluoroethylene (P.T.F.E.) the P.T.F.E. is heated at 300 to 600 DEG C., preferably 400-500 DEG C., in a salt melt having a melting point below 327 DEG C. The melt may consist of a single salt, e.g. potassium pyrosulphate or an alkali metal nitrate or nitrite; or of a mixture of salts forming a homogeneous melt e.g. potassium and cupric chlorides or potassium pyrosulphate and copper or cobaltous sulphate. Zinc chloride is not very suitable when used alone since the degradation is accompanied by carbon formation but may be used in admixture with other salts e.g. cupric chloride. Examples describe the degradation of 100 parts (by weight) of P,T.F.E. at 450 to 480 DEG C. in the following salt melts:-(i) 170 parts CuCl2/200 parts KCl; (ii) 270 parts ZnCl2/30 parts CuCl2; (iii) 240 parts ZnCl2/60 parts FeCl3; (iv) 300 parts ZnCl2; (v) 300 parts K2S2O7; (vi) 290K2S2O7/10 parts CuSO4; (vii) 300 parts KNO3. The product of examples (iii) and (iv) contained carbon.</p> |
