| 摘要 |
Pressure-sensitive adhesive sheets including adhesive tapes, adhesive drapes, adhesive bandages and the like are prepared by coating onto a flexible backing a polyolefin polymer having an intrinsic viscosity of 2.0 to 5.0, a molecular structure in which 40 to 75 percent is isotactic with the remainder containing no more than 20 percent atactic or random and a Williams' plasticity after aging on the backing of 1.5 to 3. The polyolefin polymer is prepared by polymerizing olefin monomers of two to 16 carbon chain length in the presence of a Ziegler-Natta type catalyst formed through the reaction of a transition element compound containing metal of Group IV through VI of the Mendeleff Periodic Table with an organometallic compound of a metal of Group I through III. Some of both compounds are present at the initiation of the polymerization reaction with further transition element compound being periodically added during polymerization. In an example given titanium tetrachloride is used as the transition element compound and triisobutylaluminum used as the organometallic compound in preparing the catalyst. The olefinic polymer may be a homopolymer in which instance it would be prepared from olefin monomer of six to 11 carbons and could be represented by the general formula: |
