US4272474A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing articles of ultra high molecular weight high density polyethylene
Assignee: Synergistics Chemicals Ltd
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Filing: 1979-11-06
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Granted: 1981-06-09
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Expires: 1999-11-06
Abstract
Abstract A process for producing articles of ultra high molecular weight high density polyethylene is disclosed which avoids long heating and cooling cycles, and compacting pressures in the order of 3,000 to 4,000 lbs/sq. inch. The resin is intensively mixed and thermokinetically heated in an enclosed container with a plurality of blades attached to arms rotating about an axis with a blade tip speed of at least 18 m/sec. until the resin reaches a desired discharge temperature of at least 135° C. After being discharged from the mixing step, the ultra high molecular weight resin is formed into the desired shape within a time such that degradation does not occur.
Inventors
- 👤 Zenas Crocker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 10:27
CPC Classifications
B; B29; B29B; B29B7/00; B29B7/80; B29B7/82; B01; B01F; B01F35/00; B01F35/20; B01F35/22; B01F35/221; B01F35/2214; B01F35/22142; B01F35/221421; B01F35/2215; B29B13/00; B29B13/02; B29B13/022; B29B7/002; B29B7/005; B29K; B29K2023/00; B29K2023/04; B29K2023/06; B29K2023/0658; B29K2023/0683; B29K2995/00; B29K2995/0037; B29K2995/0088; Y; Y10; Y10S; Y10S264/00; Y10S264/65
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
125 words
A process for the production of a fabricated article of a desired shape from ultra high molecular weight high density polyethylene having a molecular weight greater than 1.7×10 6 comprising the steps of: intensively mixing and thermo-kinetically heating ultra high molecular weight polyethylene resin in an enclosed container with a plurality of blades attached to arms rotating about an axis, with a blade tip speed of at least 18 m/second, the resin is heated quickly at a desired discharge temperature of at least 135° C. without shearing action occurring and with thermal degradation being controlled, discharging the resin after the intensive mixing step, and forming the ultra high molecular weight polyethylene resin into the desired shape within a time such that degradation does not occur.
Claim 2
Dependent Claim
125 words
A process for the production of a fabricated article of a desired shape from ultra high molecular weight high density polyethylene having a molecular weight greater than 1.7×10 6 comprising the steps of: intensively mixing and thermo-kinetically heating ultra high molecular weight polyethylene resin in an enclosed container with a plurality of blades attached to arms rotating about an axis, with a blade tip speed of at least 18 m/second, the resin is heated quickly at a desired discharge temperature of at least 135° C. without shearing action occurring and with thermal degradation being controlled, discharging the resin after the intensive mixing step, and forming the ultra high molecular weight polyethylene resin into the desired shape within a time such that degradation does not occur.
Claim 3
Dependent Claim
19 words
The process according to claim 1 wherein the time to reach the desired discharge temperature is within 3 minutes.
Claim 4
Dependent Claim
21 words
The process according to claim 1 wherein the blade tip speed is in the range of approximately 18 to 45 m/second.
Claim 5
Dependent Claim
37 words
The process according to claim 1 wherein the blade tip speed is at least 35 m/second and the resin reaches the desired discharge temperature in a time in the range of from approximately 8 to 24 seconds.
Claim 6
Dependent Claim
21 words
The process according to claim 1 wherein the desired discharge temperature is in the range of approximately 135° to 305° C.
Claim 7
Dependent Claim
21 words
The process according to claim 1 wherein the forming takes place in a press and the desired shape is a sheet.
Claim 8
Dependent Claim
24 words
The process according to claim 1 wherein the forming takes place in a press and desired shape is a coating layer on a substrate.
Claim 9
Dependent Claim
18 words
The process according to claim 1 wherein the forming takes place at a pressure below 1000 lbs/sq. inch.
Claim 10
Dependent Claim
13 words
The process according to claim 7 wherein the substrate is a metal plate.
Claim 11
Dependent Claim
18 words
The process according to claim 6 wherein the thickness of the finished sheet is at least 0.004 inches.
Claim 12
Dependent Claim
36 words
The process according to claim 1 wherein the resin reaches a discharge temperature of at least 240° C. in the intensive mixing step and the specific gravity is in the range of approximately 0.94 to 0.96.
Claim 13
Dependent Claim
13 words
The process according to claim 1 wherein the forming step is compression molding.
Claim 14
Dependent Claim
31 words
The process according to claim 6 or claim 7 wherein the press exerts a pressure in the range of approximately 320 to 740 lbs/sq. inch over the surface of the sheet.
Claim 15
Dependent Claim
79 words
The process according to claim 12 wherein the forming step includes a piston forcing the resin into a mold and including the step of pre-heating the piston and mold to at least 95° C., the piston exerting a constant pressure for approximately 3 minutes whilst the mold is heated to at least 95° C., and a cooling step whilst the piston still exerts the constant pressure for a time in the range of from approximately 3 to 5 minutes.
Claim 16
Dependent Claim
31 words
The process according to claim 1 wherein the desired shape is a billet which is cooled to a temperature suitable for forming into a finished article by direct stamping or forging.
Claim 17
Dependent Claim
22 words
The process according to claim 1 wherein the resin is discharged from the intensive mixing step directly into a compression molding step.
Claim 18
Dependent Claim
14 words
The process according to claim 1 wherein the forming occurs in a ram extruder.
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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) | 1984-06-08 | 1984-12-08 | 1985-06-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-06-08 | 1988-12-08 | 1989-06-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-06-08 | 1992-12-08 | 1993-06-09 | $7700.00 | Window Closed / Lapsed |