Patent US2293438A successfully refreshed from Google Patents.
US4460750A
Expired / Lapsed
US
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Process for the treatment of linear low density polyethylene by organic peroxides which generate free radicals
Assignee: BP Chemicals Ltd
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Filing: 1982-06-25
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Granted: 1984-07-17
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Expires: 2002-06-25
Abstract
Abstract The invention relates to a process of thermomechanical treatment in the molten state, in the presence of organic peroxides, of co-polymers with a density less than 0.935, obtained by co-polymerization under a pressure of less than 4 MP a of ethylene and a higher alpha-olefin. The co-polymers thus treated may advantageously be used for the manufacture of finished objects such as films according to the current techniques of conversion of "high pressure" type polyethylene.
Inventors
- 👤 Jean-Paul Thiersault
- 👤 Alain Senez
- 👤 Jean L. Vidal
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:40
CPC Classifications
C; C08; C08K; C08K5/00; C08K5/04; C08K5/14; B; B29; B29C; B29C48/00; B29C48/25; B29C48/92; C08F; C08F8/00; C08J; C08J5/00; C08J5/18; B29C2948/00; B29C2948/92; B29C2948/92504; B29C2948/92514; B29C2948/92704; B29C48/022; B29C48/78; B29C48/80; B29C48/802; C08F2800/00; C08F2800/20; C08F2810/00; C08F2810/10; C08J2323/00; C08J2323/26; C08J2323/30
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
160 words
A process for treating co-polymers of linear low density polyethylene having a density of less than 0.935, a fluidity index at 190° C. under 2.16 kg as per NFT 51016 standard, Method A, of between 0.3 and 50, and a branching index greater than 0.95, in which the co-polymer is obtained by copolymerization under a pressure less than 4 MP a , of a mixture of ethylene and a higher alpha-olefin containing 4 to 20 percent by weight of the higher alpha-olefin, comprising treating the co-polymer thermomechanically in the molten state at a temperature less than 220° C., in the presence of an organic peroxide which produces free radicals, in which the organic peroxide is employed in an amount within the range of 0.005% to 1% by weight of the co-polymer, such that the treated co-polymer has a branching index within the range of 0.8 to 0.95 and its gelling rate, as measured by extraction with boiling xylene, is zero.
Claim 2
Dependent Claim
160 words
A process for treating co-polymers of linear low density polyethylene having a density of less than 0.935, a fluidity index at 190° C. under 2.16 kg as per NFT 51016 standard, Method A, of between 0.3 and 50, and a branching index greater than 0.95, in which the co-polymer is obtained by copolymerization under a pressure less than 4 MP a , of a mixture of ethylene and a higher alpha-olefin containing 4 to 20 percent by weight of the higher alpha-olefin, comprising treating the co-polymer thermomechanically in the molten state at a temperature less than 220° C., in the presence of an organic peroxide which produces free radicals, in which the organic peroxide is employed in an amount within the range of 0.005% to 1% by weight of the co-polymer, such that the treated co-polymer has a branching index within the range of 0.8 to 0.95 and its gelling rate, as measured by extraction with boiling xylene, is zero.
Claim 3
Dependent Claim
29 words
A process as claimed in claim 1 in which the organic peroxide is employed in an amount within the range of 0.02% to 0.2% by weight of the co-polymer.
Claim 4
Dependent Claim
51 words
A process as claimed in claim 1 in which the co-polymer is obtained from a mixture of ethylene and a C 3 -C 8 alpha-olefin by copolymerization in the presence of a catalyst containing a compound of a transition metal of sub-groups IVa, Va, VIa of the Periodic Table of Elements.
Claim 5
Dependent Claim
24 words
A process as claimed in claim 3 in which the alpha-olefin is selected from the group consisting of propylene, n-butene-1, methyl-4-pentene-1, n-hexene-1, and n-octene-1.
Claim 6
Dependent Claim
30 words
A process as claimed in claim 1 in which the organic peroxide is selected from the group consisting of di-terbutyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-dimethyl-2,5-di(terbutylperoxy)-hexane, 2,5-dimethyl-2,5-di(terbutylperoxy)-hexyne, butyl-4,4-bis(terbutylperoxyvalerate), dicumyl hydroperoxide, 1,1-bis(terbutylperoxy)-3,3,5-trimethylcyclohexane, 1,3-di(terbutylperoxy)di-isopropylbenzene.
Claim 7
Dependent Claim
97 words
A process as claimed in claim 1 in which the co-polymer is subjected to the thermomechanical treatment in two stages at temperatures within the range of 130° C. to 220° C., the first stage of the treatment being carried out at a temperature at which the organic peroxide used has a half-life period greater than 13 times the duration of this first treatment stage, the second stage of treatment being carried out at a temperature at which the organic peroxide used has a half-life period of less than 0.4 times the duration of this second treatment period.
Claim 8
Dependent Claim
8 words
Co-polymers prepared by the process of claim 1.
Claim 9
Dependent Claim
12 words
Film formed of the co-polymers produced by the method of claim 1.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-07-17 | 1988-01-16 | 1988-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-17 | 1992-01-16 | 1992-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-17 | 1996-01-16 | 1996-07-17 | $7700.00 | Window Closed / Lapsed |