| 摘要 |
1319767 Masking tape ADHESIVE TAPES Ltd 15 Oct 1970 [24 Oct 1969] 52291/69 Heading B2E [Also in Division B3] A pressure-sensitive adhesive tape for use as a mask in the deep drawing of metal sheets comprises a polymeric film comprising a major proportion of propylene units and having a recovery after 2 hours of less than 0.35 at 150% elongation and an elongation at break in both transverse and longitudinal directions exceeding 500% coated on one face with a pressure-sensitive adhesive. The film may be an unoriented polypropylene homopolymer or an unoriented ethylene/propylene copolymer and is preferably between 25 and 150 microns thick. The film may be treated by electrical discharge or have a primer coating applied thereto before the application of the pressuresensitive adhesive. In the Example a film of an ethylene/propylene copolymer 50 microns thick is subjected to electrical discharge and is then coated with a mixture of a natural rubber, cyclized natural rubber and an isocyanate curing agent and then with the pressure-sensitive adhesive which comprises natural rubber and a polyterpene tackifier. |
