Polyethylene block-graft copolymers and method for preparing the same
Abstract
Abstract The present invention provides a block-graft copolymer of polyethylene and saponified ethylene vinyl acetate with improved moisture permeability by heating a mixture of polyethylene and a saponified ethylene-vinyl acetate copolymer to an elevated temperature and kneading the mixture under pressure. The saponified ethylene-vinyl acetate copolymer has a degree of saponification of 99% or more and consists of from 30 to 50 mol percent of ethylene, the remainder being vinyl acetate, the polyethylene being a powdery high density polyethylene which has not been subjected to heating and kneading after polymerization, the mixture containing the high density polyethylene and the saponified ethylene-vinyl acetate copolymer at a weight ratio of 98:2 to 80:20 and from 0.2 to 0.6 percent by weight based on the weight of the mixture, of a radical forming catalyst, and the mixture being heated to a temperature of from 200* to 205*C and kneaded under a pressure of 330 to 470 kg/cm2.
Inventors
- 👤 A Kisimoto
- 👤 S Hirata
- 👤 H Ueno
Bibliographic Details
Claims Analysis
Total Claims: 2References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1977-01-28 | 1977-07-30 | 1978-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-28 | 1981-07-30 | 1982-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-28 | 1985-07-30 | 1986-01-29 | $7700.00 | Window Closed / Lapsed |