| 摘要 |
PURPOSE:A Ziegler-Natta catalyst is used to effect the subsequent polymerization of propylene, ethylene and an alpha-olefin in order in a specific proportion to produce a terpolymer with high hot tack, heat seal, transparency, toughness, lubricity and blocking properties. CONSTITUTION:A Ziegler-Natta catalyst, preferably titanium tetracloride, is used of effect the polymerization of ethylene, propylene and an alpha-olefin wherein at the first step, a mixture of propylene-ethylene is added at a weight ratio of (90-99.5)/ (10-0.5), preferably (94-99)/(6-1) and polymerized so that the amount of the copolymer becomes 20-90, preferably 30-80wt% of the total copolymer and at the second stage another mixture of propylene-an alpha-olefin such as butene is fed at a weight ratio of (60-98)/(40-2) so that the copolymer becomes 10-80wt% resultingly the weight ratio of propylene/ethylene/alpha-olefin becomes (99-80)/(0.5- 5)/(0.5-15). |
