US4774292A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Propylene compositions with improved impact strength
Assignee: BP Chemicals Ltd
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Filing: 1987-12-16
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Granted: 1988-09-27
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Expires: 2007-12-16
Abstract
Abstract The invention concerns polypropylene compositions with improved impact strength adapted for conversion to finished articles by extrusion drawing, extrusion blow-molding or thermoforming characterized in that they contain: (a) 40 to 98% by weight of isotactic polypropylene (b) 2 to 60% by weight of a copolymer of linear low density polyethylene type with a density of up to 0.935, obtained by copolymerizing a mixture of ethylene and one or more upper alpha-olefins, by a copolymerizing process at a pressure below 4.10 6 Pa, in the absence of any liquid hydrocarbons.
Inventors
- 👤 Jean P. Thiersault
- 👤 Jean C. Roustant
- 👤 Alain Senez
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:51
CPC Classifications
C; C08; C08L; C08L23/00; C08L23/02; C08L23/04; C08L23/08; C08L23/0807; C08L23/0815; C08L23/10; C08L23/12
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
141 words
A polypropylene composition having improved impact strength, comprising (a) at least 80% and up to 98% by weight of isotactic polypropylene having a mean molecular weight within the range of 50,000-500,000, and (b) 2 to at most 20% by weight of a linear low density polyethylene having a density from 0.92 up to 0.935, a crystalline fraction characterised by a melting point of about 120° C. and an amorphous fraction characterized by a broad fusion range below 115° C., determined by differential enthalpy analysis, the said linear low density polyethylene being further obtained by a copolymerizing 85 to 96% by weight ethylene with 4 to 15% by weight of one or more C 3 -C 8 alpha-olefins in the presence of a solid catalyst based on titanium at a pressure below 4.10 6 Pa and in the absence of liquid hydrocarbon.
Claim 2
Dependent Claim
141 words
A polypropylene composition having improved impact strength, comprising (a) at least 80% and up to 98% by weight of isotactic polypropylene having a mean molecular weight within the range of 50,000-500,000, and (b) 2 to at most 20% by weight of a linear low density polyethylene having a density from 0.92 up to 0.935, a crystalline fraction characterised by a melting point of about 120° C. and an amorphous fraction characterized by a broad fusion range below 115° C., determined by differential enthalpy analysis, the said linear low density polyethylene being further obtained by a copolymerizing 85 to 96% by weight ethylene with 4 to 15% by weight of one or more C 3 -C 8 alpha-olefins in the presence of a solid catalyst based on titanium at a pressure below 4.10 6 Pa and in the absence of liquid hydrocarbon.
Claim 3
Dependent Claim
32 words
The composition of claim 1, further comprising (c) said composition showing only one fusion peak in differential enthalpy analysis, characterised as if the polypropylene crystallised together with the linear low density polyethylene.
Claim 4
Dependent Claim
16 words
The composition of claim 1, wherein the LLDPE has a density from 0.92 up to 0.928.
Claim 5
Dependent Claim
16 words
The composition of claim 1, wherein the LLDPE has a density from 0.928 up to 0.935.
Claim 6
Dependent Claim
36 words
The compositions of claim 1, wherein the linear low density polyethylene is prepared from a mixture of ethylene and one or more upper alpha-olefins selected from the group consisting of propylene, 1-n-butene, 1-n-hexene, 4-methyl-1-pentene or 1-n-octene.
Claim 7
Dependent Claim
20 words
A method of preparing the compositions of claim 1, comprising mixing the constituents (a) and (b) in the molten state.
Claim 8
Dependent Claim
34 words
The method of claim 1, wherein the mixture in the molten state is produced by the introduction of powders or granules of the constituents directly in a machine for conversion to a finished article.
Claim 9
Dependent Claim
33 words
A process for the manufacture of finished articles comprising providing a composition of claim 1, and treating said composition by extrusion drawing, extrusion blow-moulding or thermoforming, so as to produce said finished article.
Claim 10
Dependent Claim
29 words
The method as claimed in claim 1 in which the machine for conversion of the powders or granules to a finished article comprises an extruder or injection molding machine.
Claim 11
Dependent Claim
22 words
The composition of claim 1, wherein the LLDPE is a copolymer of ethylene and propylene or a copolymer of ethylene and 1-n-butene.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-09-27 | 1992-03-28 | 1992-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-27 | 1996-03-28 | 1996-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-27 | 2000-03-28 | 2000-09-27 | $7700.00 | Window Closed / Lapsed |