US4110391A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the manufacture of molded articles from polyolefins with molecular weights of at least one million
Assignee: Hoechst AG
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Filing: 1977-07-27
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Granted: 1978-08-29
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Expires: 1997-07-27
Abstract
Abstract A process for the manufacture of a molded article from a powder form of a polyolefin of molecular weight of at least one million which comprises introducing a homopolymer of ethylene or a copolymer of ethylene with an α-olefin of 3 to 10 carbon atoms having a molecular weight of at least one million into a mold loosely closed with a plug, heating the same in said mold in an inert atmosphere at a temperature of 150° to 250° C, whereby said polyolefin is transformed into a rubbery elastic state, thereafter compressing said polyolefin in said mold for at least two minutes at a pressure of 2.5 to 25 N/mm 2 and thereafter compressing said polyolefin for at least one minute at a pressure of 40 to 100 N/mm 2 .
Inventors
- 👤 Josef Berzen
- 👤 Johannes Theyssen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 09:46
CPC Classifications
B; B29; B29C; B29C43/00; B29C43/006; B29C43/003; B29C43/32; B29C43/58; B29C2043/5808; B29C2791/00; B29C2791/001; B29K; B29K2023/00; B29K2023/04; B29K2023/06; B29K2023/0658; B29K2023/0683; B29K2105/00; B29K2105/0085; B29K2105/25; B29K2105/251; B29K2995/00; B29K2995/0037; B29K2995/0088; B29L; B29L2031/00; B29L2031/753; B29L2031/7532
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
128 words
A process for the manufacture of a molded article from a powder form of a polyolefin of molecular weight of at least one million which comprises introducing a homopolymer of ethylene or a copolymer of ethylene with an α-olefin of 3-10 carbon atoms having a molecular weight of at least one million into a mold loosely closed with a plug, heating the same in said mold in an inert atmosphere at a temperature of 150° to 250° C whereby said polyolefin is transformed into a rubbery-elastic state, thereafter compressing said polyolefin in said mold for at least two minutes at a pressure of 2.5 to 25 N/mm 2 and thereafter compressing said polyolefin for at least one minute at a pressure of 40 to 100 N/mm 2 .
Claim 2
Dependent Claim
128 words
A process for the manufacture of a molded article from a powder form of a polyolefin of molecular weight of at least one million which comprises introducing a homopolymer of ethylene or a copolymer of ethylene with an α-olefin of 3-10 carbon atoms having a molecular weight of at least one million into a mold loosely closed with a plug, heating the same in said mold in an inert atmosphere at a temperature of 150° to 250° C whereby said polyolefin is transformed into a rubbery-elastic state, thereafter compressing said polyolefin in said mold for at least two minutes at a pressure of 2.5 to 25 N/mm 2 and thereafter compressing said polyolefin for at least one minute at a pressure of 40 to 100 N/mm 2 .
Claim 3
Dependent Claim
23 words
A process according to claim 1 wherein the polyolefin is heated in the inert atmosphere at a temperature of 190° to 210° C.
Claim 4
Dependent Claim
26 words
A process according to claim 1 wherein following compressing at 40 to 100 N/mm 2 the molded article so prepared is cooled pressure-free in the mold.
Claim 5
Dependent Claim
21 words
A process according to claim 1 wherein a copolymer is molded containing up to 5 percent of the C 3-10 α-comonomer.
Claim 6
Dependent Claim
14 words
A process according to claim 1 wherein said polyolefin is a homopolymer of ethylene.
Claim 7
Dependent Claim
18 words
A process according to claim 1 wherein said polymer has a molecular weight of more than 3.5 million.
Claim 8
Dependent Claim
17 words
A process according to claim 1 wherein the polyolefin has a grain size of 60 to 500μ.
Claim 9
Dependent Claim
19 words
A process according to claim 1 wherein the polyolefin has bulk weight of between 200 g/l and 400 g/l.
Claim 10
Dependent Claim
22 words
A process according to claim 1 wherein the plug exerts a pressure on the powder of less than 0.01 N/mm 2 .
Claim 11
Dependent Claim
20 words
A process according to claim 1 wherein the powder is heated in the inert atmosphere for at least 2 hours.
Claim 12
Dependent Claim
16 words
A process according to claim 10 wherein the heating is performed in the absence of oxygen.
Claim 13
Dependent Claim
42 words
A process according to claim 1 wherein after the heating the molded article is compressed at 5 to 10 N/mm 2 and thereafter compressing of the molded article for at least one minute is performed at 40 to 60 N/mm 2 .
Claim 14
Dependent Claim
36 words
A process according to claim 1 wherein the compressing at 2.5 to 25 N/mm 2 is performed for about 4 minutes and the compressing at 40 to 100 N/mm 2 is performed for about one minute.
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) | 1981-08-28 | 1982-02-27 | 1982-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-08-28 | 1986-02-27 | 1986-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-08-28 | 1990-02-27 | 1990-08-29 | $7700.00 | Window Closed / Lapsed |