US4254072A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for high modulus polymeric materials
Assignee: BTG International Ltd
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Filing: 1978-09-19
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Granted: 1981-03-03
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Expires: 1998-09-19
Abstract
Abstract A process for the production of a high modulus filament of polyethylene which comprises heating high density polyethylene to a temperature above its melting point, extruding the polymer to form a filament, subjecting the filament immediately after extrusion to a tension under such conditions that the filament is shaped without substantial orientation of its molecules, cooling the filament at a rate of cooling in excess of 15 DEG C. per minute, and drawing the filament to a high draw ratio.
Inventors
- 👤 Giancarlo Capaccio
- 👤 Francis S. Smith
- 👤 Ian M. Ward
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 19:50
CPC Classifications
D; D02; D02J; D02J1/00; D02J1/22; D02J1/223; D01; D01D; D01D5/00; D01D5/08; D01D5/088; D01D5/0885; D01D5/098; D01F; D01F6/00; D01F6/02; D01F6/04
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
117 words
A process for the production of a high modulus filament of polyethylene having 50,000<Mw<200,000 and 5,000<Mn<25,000 which comprises heating high density polyethylene to a temperature above its melting point, extruding the polymer to form a filament, subjecting the filament immediately after extrusion to a tension while maintaining the filament at an elevated temperature such that the filament is shaped without substantial orientation of its molecules, cooling the filament at a rate of cooling in excess of 15° C. per minute to yield a spun filament having a birefringence of not more than 3×10 -3 and a density of not more than 0.96 gm. per cc., and drawing the filament to a draw ratio of at least 20.
Claim 2
Dependent Claim
117 words
A process for the production of a high modulus filament of polyethylene having 50,000<Mw<200,000 and 5,000<Mn<25,000 which comprises heating high density polyethylene to a temperature above its melting point, extruding the polymer to form a filament, subjecting the filament immediately after extrusion to a tension while maintaining the filament at an elevated temperature such that the filament is shaped without substantial orientation of its molecules, cooling the filament at a rate of cooling in excess of 15° C. per minute to yield a spun filament having a birefringence of not more than 3×10 -3 and a density of not more than 0.96 gm. per cc., and drawing the filament to a draw ratio of at least 20.
Claim 3
Dependent Claim
88 words
A process according to claim 1 wherein the filament is drawn to a high draw ratio (X) of at least 20 in a fluid at temperature T within the range 90° C. to 130° C. at a draw speed of at least 200 feet per minute but not greater than Z ft per minute where ##EQU3## in which Δ is the birefringence of the spun filament and is not greater than 3×10 -3 , to give a material having a 0.5% secant modulus greater than 240 g.per dtex.
Claim 4
Dependent Claim
21 words
A process according to claim 1 wherein the polymer has a number average molecular weight in the range 5,000 to 15,000.
Claim 5
Dependent Claim
53 words
A process according to claim 3 wherein the polymer has a ratio of weight average molecular weight Mw to number average molecular weight Mn such that for Mn greater than 10 4 , Mw/ Mn is less than 8, and for Mn less than 10 4 , Mw/ Mn is less than 20.
Claim 6
Dependent Claim
15 words
A process according to claim 1 wherein the spun yarn is drawn in a liquid.
Claim 7
Dependent Claim
55 words
A process according to claim 1 wherein, on leaving the extruder, the polyethylene passes through a zone of gaseous medium which, adjacent the filament, is at a temperature T of at least: ##EQU4## wherein L is the length of the zone in feet, L being at least 1 and T being at least 130° C.
Claim 8
Dependent Claim
29 words
A process according to claim 6 wherein the temperature of the gaseous medium adjacent to the filament decreases in the direction of filament travel to a value defined therein.
Claim 9
Dependent Claim
11 words
A process according to claim 2 wherein the fluid comprises air.
Claim 10
Dependent Claim
12 words
A process according to claim 2 wherein the fluid comprises a liquid.
Claim 11
Dependent Claim
11 words
A process according to claim 9 wherein the liquid comprises glycerol.
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) | 1984-03-02 | 1984-09-01 | 1985-03-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-02 | 1988-09-01 | 1989-03-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-02 | 1992-09-01 | 1993-03-03 | $7700.00 | Window Closed / Lapsed |