| 摘要 |
PURPOSE:To improve the heat resistivity and mechanical strength of a thermal shrinkage or thermal expansion tube by elongating silane-graft crystalline polypropylene of which gel component rate is 20-80wt%. CONSTITUTION:Silanegraft crystalline polypropylene of which gel component rate is 20-80wt% is obtained by causing 0.1-15wt. part of ethylene unsaturated silane compound such as vinyl trimethoxy-silane, etc. to graft-polymerize with 100wt. part of crystalline polypropylene and it is formed into tubular shape and water-bridged in a steam chamber and then it is elongated by blowing air thereinto and a thermal shrinkage tube is formed. The tube is poor in thermal shrinkability if its gel component rate is less than 20wt% and it tends to cause cracks, if the rate exceed 80wt%. A thermal expansion tube may be made by elongating a tubular formed product in its longitudinal direction. Since a specific material is used, the tube is excellent in heat resistivity and mechanical strength. |
