| 摘要 |
PROBLEM TO BE SOLVED: To obtain a propylene homopolymer which has a tackiness point shorter than 30cm during melt spinning, has an oligomer content lower than 1,500ppm without undergoing postpolymerization for oligomer removal, and has a melt flow rate higher than 300dg/min. SOLUTION: A propylene homopolymer which has a tackiness point shorter than 30cm during melt spinning, has an oligomer content lower than 1,500ppm without undergoing post-polymerization for oligomer removal, and has a melt flow rate higher than 300dg/min is produced with a multistage fluidized bed reactor through radiation visbreaking. The homopolymer is irradiated in a substantially oxygen-free state and then subjected to a multistage treatment in the presence of a regulated amount of oxygen. This radiation visbreaking method is applicable to other propylene polymers. Propylene polymer materials produced by this method are usable, e.g., n extrusion coating, film production, and injection molding. |
