US4871813A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polymer compositions based on linear low density polyethylene and propylene copolymers
Assignee: BP Chemicals Ltd
•
Filing: 1987-08-31
•
Granted: 1989-10-03
•
Expires: 2007-08-31
Abstract
Abstract A polymer composition comprising (a) 99 to 75 weight percent of LLDPE and (b) 1 to 25 weight percent of a copolymer of propylene (CP) with 7 to 40 weight % o one or more C 4 to C 12 alpha-olefins and 0 to 10 weight % of ethylene. The propylene copolymer (CP) has a fusion enthalpy not more than 75 J/g. The composition is readily converted into uniform thickness film by extrusion blowing, and exhibits good hot tack strength during heat-sealing operations.
Inventors
- 👤 Alain Senez
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 02:33
CPC Classifications
C; C08; C08L; C08L23/00; C08L23/02; C08L23/04; C08L23/08; C08L23/0807; C08L23/0815; C08L23/10; C08L23/14
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
114 words
A polymer composition comprising: (a) from 99 to 75 weight percent of linear low density polyethylene consisting of a copolymer of ethylene with at least one alpha-olefin containing 3-12 carbon atoms, and (b) from 1 to 25 weight percent of a copolymer (CP) of propylene with 7 to 40 weight percent (based on total weight of copolymer CP) of one or more C 4 to C 12 alpha olefins and 0 to 10 weight percent of ethylene, the weight content of the ethylene, if any, in copolymer CP being less than the weight of the C 4 to 12 alpha olefin therein, said copolymer having a fusion enthalpy of not more than 75 J/g.
Claim 2
Dependent Claim
114 words
A polymer composition comprising: (a) from 99 to 75 weight percent of linear low density polyethylene consisting of a copolymer of ethylene with at least one alpha-olefin containing 3-12 carbon atoms, and (b) from 1 to 25 weight percent of a copolymer (CP) of propylene with 7 to 40 weight percent (based on total weight of copolymer CP) of one or more C 4 to C 12 alpha olefins and 0 to 10 weight percent of ethylene, the weight content of the ethylene, if any, in copolymer CP being less than the weight of the C 4 to 12 alpha olefin therein, said copolymer having a fusion enthalpy of not more than 75 J/g.
Claim 3
Dependent Claim
41 words
A composition according to claim 1 wherein the content of the linear low density polyethylene is in the range 95 to 80 weight percent, and the content of the propylene copolymer CP is in the range 5 to 20 weight percent.
Claim 4
Dependent Claim
41 words
A composition according to claim 1 characterised in that the linear low density polyethylene is obtained by copolymerisation of ethylene and at least 1 alpha olefin containing 3 to 12 carbon atoms in the presence of a Ziegler-Natta type catalytic system.
Claim 5
Dependent Claim
28 words
A composition according to claim 3 characterised in that the alpha olefin in the linear low density polyethylene is selected from propylene, 1-butene, 1-pentene, hexene-1, 4-methyl-1-pentene or 1-octene.
Claim 6
Dependent Claim
45 words
A composition according to claim 1 wherein the propylene copolymer (CP) is a copolymer of propylene and butene, a copolymer of propylene and hexene, a copolymer of propylene and 4-methyl-1-pentene, a terpolymer of propylene, 1-butene and ethylene, or a terpolymer of propylene, 4-methyl-1-pentene and ethylene.
Claim 7
Dependent Claim
26 words
A composition according to claim 1 wherein the propylene copolymer is a copolymer of propylene and 1-butene containing from 10 to 35 weight percent of 1-butene.
Claim 8
Dependent Claim
49 words
A composition according to claim 1 characterised in that the propylene copolymer (CP) is obtained by copolymerisation of a mixture of propylene and at least one alpha olefin containing 4-12 carbon atoms optionally with ethylene in the presence of a Ziegler-Natta type catalytic system adapted to polymerise propylene stereospecifically.
Claim 9
Dependent Claim
28 words
A composition according to claim 7 characterised in that the alpha olefin used to make the propylene copolymer CP is selected from 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene or 1-octene.
Claim 10
Dependent Claim
39 words
A composition according to claim 3 or claim 7 characterised in that the low linear density polyethylene and/or the propylene copolymer are obtained by a process of copolymerisation in the gaseous phase using a fluidised and/or mechanically stirred bed.
Claim 11
Dependent Claim
17 words
A composition according to claim 1 characterised in that the constituents are mixed in the molten condition.
Claim 12
Dependent Claim
36 words
A composition according to claim 10 characterised in that the mixture in the molten condition is produced from a mixture of powders or pellets of the constituents, directly in a machine for conversion into finished articles.
Claim 13
Dependent Claim
44 words
A polymer composition as defined in claim 1 wherein said linear low density polyethylene has a melting enthalpy which corresponds to a degree of crystallinity of between about 25% and 50%, such crystallinity being expressed with reference to a high density linear ethylene homopolymer.
References Cited (Backward Citations)
US4430457A
Cited
JPS58217534A
Cited
US4563504A
Cited
JPS5941342A
Cited
GB2133018A
Cited
JPS59202244A
Cited
EP0128046B1
Cited
GB2152516A
Cited
JPS60161442A
Cited
EP0191990A2
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-10-02 | 1993-04-03 | 1993-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-02 | 1997-04-03 | 1997-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-02 | 2001-04-03 | 2001-10-03 | $7700.00 | Window Closed / Lapsed |