US4282177A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for reducing sharkskin melt fracture during extrusion of ethylene polymers
Assignee: Union Carbide Corp
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Filing: 1979-12-12
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Granted: 1981-08-04
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Expires: 1999-12-12
Abstract
Abstract A method for reducing sharkskin melt fracture during extrusion of a molten narrow molecular weight distribution linear ethylene polymer which comprises extruding said polymer through a die having a die gap greater than about 50 mils and wherein at least a portion of one surface of the die lip and/or die land in contact with the molten polymer is at an angle of divergence or convergence relative to the axis of flow of the molten polymer through the die.
Inventors
- 👤 Stuart J. Kurtz
- 👤 Theodore R. Blakeslee, III
- 👤 Leonard S. Scarola
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 04:37
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/022; B29C48/03; B29C48/07; B29C48/08; B29C48/09; B29C48/10; B29K; B29K2023/00; B29K2023/04; B29K2023/06; B29K2995/00; B29K2995/0037; B29K2995/0063; B29K2995/0072; B29K2995/0073
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
96 words
A process for reducing the melt fracture during extrusion of a molten narrow molecular weight distribution linear ethylene polymer under conditions of flow rate and melt temperature which would otherwise produce higher levels of melt fracture, which comprises extruding said polymer through a die having a die gap greater than about 50 mils and wherein at least a portion of one surface of the die lip and/or die land in contact with the molten polymer is at an angle of divergence or convergence relative to the axis of flow of the molten polymer through the die.
Claim 2
Dependent Claim
96 words
A process for reducing the melt fracture during extrusion of a molten narrow molecular weight distribution linear ethylene polymer under conditions of flow rate and melt temperature which would otherwise produce higher levels of melt fracture, which comprises extruding said polymer through a die having a die gap greater than about 50 mils and wherein at least a portion of one surface of the die lip and/or die land in contact with the molten polymer is at an angle of divergence or convergence relative to the axis of flow of the molten polymer through the die.
Claim 3
Dependent Claim
20 words
A process as in claim 1 wherein the die gap is greater than about 50 mils to about 200 mils.
Claim 4
Dependent Claim
36 words
A process as in claim 1 wherein at least a portion of the surface of the die gap and/or die land is at a divergent angle relative to the axis of flow of the molten polymer.
Claim 5
Dependent Claim
26 words
A process as in claim 3 wherein the divergent angle is from 1° to about 45° relative to the axis of flow of the molten polymer.
Claim 6
Dependent Claim
36 words
A process as in claim 1 wherein at least a portion of the surface of the die gap and/or die land is at a convergent angle relative to the axis of flow of the molten polymer.
Claim 7
Dependent Claim
17 words
A process as in claim 5 wherein the convergent angle is from about 5° to about 50°.
Claim 8
Dependent Claim
15 words
A process as in claim 1 wherein the ethylene polymer is formed into blown film.
Claim 9
Dependent Claim
15 words
A process as in claim 1 wherein the ethylene polymer is slot cast into film.
Claim 10
Dependent Claim
14 words
A process as in claim 1 wherein the ethylene polymer is formed into pipe.
Claim 11
Dependent Claim
17 words
A process as in claim 1 wherein the ethylene polymer is a low density ethylene hydrocarbon copolymer.
Claim 12
Dependent Claim
36 words
A process as in claim 10 in which said copolymer is a copolymer of ethylene and at least one C 3 to C 8 alpha olefin having a melt index of about ≧0.1 to about ≦20.
Claim 13
Dependent Claim
33 words
A process as in claim 11 in which said copolymer is a copolymer of ≧90 mol percent ethylene and ≦10 mol percent of at least one C 3 to C 8 alpha olefin.
Claim 14
Dependent Claim
33 words
A process as in claim 12 in which said copolymer has a molecular weight distribution of about ≧2.7 to ≦6.0 and a total unsaturation content of about ≧0.1 to ≦0.3 C═C/1000 C atoms.
Claim 15
Dependent Claim
33 words
A process as in claim 12 in which said copolymer has a melt flow ratio of about ≧22 to ≦40 and a total unsaturation content of about ≧0.1 to ≦0.3 C═C/1000 C atoms.
Claim 16
Dependent Claim
33 words
A process as in claim 1 wherein said ethylene polymer is extruded through said die at a shear rate, at the exit of said die, of up to about 200 sec. -1 .
Claim 17
Dependent Claim
33 words
A process as in claim 15 wherein said ethylene polymer is extruded through said die at a shear rate, at the exit of said die, of up to about 100 sec. -1 .
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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) | 1984-08-03 | 1985-02-02 | 1985-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-03 | 1989-02-02 | 1989-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-03 | 1993-02-02 | 1993-08-04 | $7700.00 | Window Closed / Lapsed |