| 摘要 |
Thermally degraded polymers are made by heating at 260-420 DEG C a block copolymer of propylene and butene-1 containing 50-90% of crystalline polymer and 50-5% of amorphous polymer, the heating being effected for a time sufficient to produce a product having a viscosity of 500-30,000 centipoises at 190 DEG C. The copolymer starting material may be made by polymerizing propylene in the presence of a stereospecific polymerization catalyst, e.g. a mixture of titanium trichloride and lithium aluminium hydride, and then, in a second stage, polymerizing butene-1 in the same reaction system. The degraded copolymers are used in coating applications.ALSO:Paper is melt-coated with a thermally degraded block copolymer of propylene and butene-1 which contains 50-95% of crystalline polymer and 50-5% of amorphous polymer and has a viscosity of 500-30,000 centipoises at 190 DEG C (see Division C3). |
