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Patent US3975481A successfully refreshed from Google Patents.
US3975481A
Expired / Lapsed
US
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Method for molding ultra-high molecular weight polyethylene molding powder
Assignee: Honeywell International Inc
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Filing: 1974-06-27
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Granted: 1976-08-17
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Expires: 1994-06-27
Abstract
Abstract A method for molding powder of ultra-high molecular weight, linear polyethylene comprising particles of less than 100 micron mean particle size having narrow particle size distribution is free-sinterable to form solid articles by a process comprising (a) molding a solid preform by compressing the polyethylene molding powder at a temperature below its crystalline melting point under pressure of at least 2,000 p.s.i., (b) releasing the pressure and (c) free-sintering the preform at temperature above its crystalline melting point.
Inventors
- 👤 Eugene R. Baumgaertner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 23:44
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/12; B; B29; B29C; B29C43/00; B29C43/003; B29C43/006; B29C67/00; B29C67/02; B29C67/04; C08J5/00; B29C2791/00; B29C2791/001; B29K; B29K2023/00; B29K2023/04; B29K2023/06; B29K2023/0658; B29K2023/0683; B29K2105/00; B29K2105/25; B29K2105/251; C08J2323/00; C08J2323/02; C08J2323/04
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
143 words
The method for making solid articles of ultra-high molecular weight polyethylene powder comprising: a. compressing said powder having a molecular weight of at least 1 × 10 6 and a density from 0.92 to 0.99 gm./cc. comprising particles of less than 100 micron mean particle size having a distribution function of less than 0.80 under a pressure of at least 2,000 p.s.i. at a temperature below the crystalline melting point of the polyethylene to form a solid preform, b. releasing the pressure, c. free-sintering the preform at a temperature above said crystalline melting point for a time sufficient to allow sintering into an article having the tensile strength and elongation set forth hereinbelow, and d. cooling said preform to ambient temperatures to thereby form a solid article having a tensile strength of at least 4,000 p.s.i. and elongation of at least 200 percent.
Claim 2
Independent Claim
143 words
The method for making solid articles of ultra-high molecular weight polyethylene powder comprising: a. compressing said powder having a molecular weight of at least 1 × 10 6 and a density from 0.92 to 0.99 gm./cc. comprising particles of less than 100 micron mean particle size having a distribution function of less than 0.80 under a pressure of at least 2,000 p.s.i. at a temperature below the crystalline melting point of the polyethylene to form a solid preform, b. releasing the pressure, c. free-sintering the preform at a temperature above said crystalline melting point for a time sufficient to allow sintering into an article having the tensile strength and elongation set forth hereinbelow, and d. cooling said preform to ambient temperatures to thereby form a solid article having a tensile strength of at least 4,000 p.s.i. and elongation of at least 200 percent.
Claim 3
Dependent Claim
18 words
The method of claim 1 wherein the molding powder is compressed under pressure of at least 6,000 p.s.i.
Claim 4
Dependent Claim
19 words
The method of claim 2 employing a molding powder comprising particles of less than 75 micron mean particle size.
Claim 5
Dependent Claim
31 words
The method of claim 3 wherein the molding powder has a molecular weight of at least 2 × 10 6 and comprises particles having a distribution function of less than 0.70.
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) | 1979-08-17 | 1980-02-16 | 1980-08-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-17 | 1984-02-16 | 1984-08-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-17 | 1988-02-16 | 1988-08-17 | $7700.00 | Window Closed / Lapsed |