| 摘要 |
1463277 Removing Ziegler catalyst residues from polyolefin MITSUBISHI CHEMICAL INDUSTRIES Ltd 10 June 1975 [13 June 1974] 24836/75 Heading C3P Preventing the discoloration of polyolefins which have been produced by polymerization in an inert gas using a Ziegler catalyst, by rendering the catalyst residues inert by contacting the impure polyolefin with a weakly reactive gas containing oxygen and/or steam diluted with an inert gas. The content of O 2 in the inert gas is preferably 0À05-0À5 mole per cent and/or the concentration of steam is preferably 0À05-1À0 mole per cent. The polymer may be in the form of a powder or granules, or may be in a molten or semi-molten state, when treated. The treatment of the solid polymer is preferably carried out at 40-110‹ C. The contact with the weakly reactive gas may be effected during a two-step pelletizing operation or during a drying operation. |
