Patent US4126661A successfully refreshed from Google Patents.
US4126661A
Expired / Lapsed
US
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Process for producing products of cross-linked thermoplastic material
Assignee: Pont a Mousson SA
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Filing: 1977-03-21
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Granted: 1978-11-21
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Expires: 1997-03-21
Abstract
Abstract The process is of the type comprising continuously shaping a mixture of thermoplastic material and crosslinking agent by pressure and then effecting the cross-linking by the cross-linking agent. The cross-linkable mixture is placed inside a sintering zone in which it is subjected to the action of pressure and a sintering temperature at the same time as it is put into shape. It is then conveyed without modification of shape by means of the same pressure to a zone where the cross-linking is effected by a rise in temperature. The device comprises in the following order, along a common axis, a device supplying the cross-linkable mixture, a sintering die and a cross-linking die. These dies define a continuous space in which the pressure is exerted and each comprise heating means.
Inventors
- 👤 Thierry Fulconis
- 👤 Bernard Ginglinger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:18
CPC Classifications
B; B29; B29C; B29C43/00; B29C43/32; B29C43/52; B29C48/00; B29C48/022; B29C48/25; B29C48/36; B29C48/475; B29C48/78; B29C48/80; B29C48/83; B29C48/832; B29C48/92; B29C2948/00; B29C2948/92; B29C2948/92504; B29C2948/92704; B29C2948/92819; B29C2948/92857; B29C2948/92876; B29C2948/92895; B29C48/03; B29C48/04; B29C48/09; B29C48/12; B29K; B29K2101/00; B29K2101/10; B29K2105/00; B29K2105/24; B29K2105/25; B29K2105/251; B29K2301/00; B29K2301/10
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
150 words
A process for producing a hollow tubular product of cross-linked high-density polyethylene from an essentially powdered cross-linkable mixture comprising said high-density polyethylene and a cross-linking agent, comprising forcing said mixture into and through an elongate passageway which extends longitudinally along an axis and has an annular cross-sectional shape, by exerting a pressure on said mixture in a direction parallel to said axis while maintaining the cross-sectional shape and size of the whole of said mixture in said passageway constant and while maintaining an upstream part of said passageway relative to the direction of travel of said mixture at a first temperature sufficient to sinter said mixture but insufficient to cross-link said high-density polyethylene and maintaining a downstream part of said passageway adjacent to said upstream part relative to the travel of said mixture at a second temperature distinctly higher than said first temperature and sufficient to cross-link said high-density polyethylene.
Claim 2
Dependent Claim
150 words
A process for producing a hollow tubular product of cross-linked high-density polyethylene from an essentially powdered cross-linkable mixture comprising said high-density polyethylene and a cross-linking agent, comprising forcing said mixture into and through an elongate passageway which extends longitudinally along an axis and has an annular cross-sectional shape, by exerting a pressure on said mixture in a direction parallel to said axis while maintaining the cross-sectional shape and size of the whole of said mixture in said passageway constant and while maintaining an upstream part of said passageway relative to the direction of travel of said mixture at a first temperature sufficient to sinter said mixture but insufficient to cross-link said high-density polyethylene and maintaining a downstream part of said passageway adjacent to said upstream part relative to the travel of said mixture at a second temperature distinctly higher than said first temperature and sufficient to cross-link said high-density polyethylene.
Claim 3
Dependent Claim
25 words
A process as claimed in claim 1, wherein said cross-sectional size and shape are maintained constant by making said passageway cylindrical throughout the length thereof.
Claim 4
Dependent Claim
19 words
A process as claimed in claim 1, wherein said pressure is exerted by a piston coaxial with said passageway.
Claim 5
Dependent Claim
44 words
A process as claimed in claim 1, wherein, in the case of a polyethylene having a high density exceeding 0.95 and a molecular weight equal to at least 200,000, the temperature of the sintering zone of said passageway is between 140° and 200° C.
Claim 6
Dependent Claim
23 words
A process as claimed in claim 4, wherein the temperature of the sintering zone of said passageway is between 160° and 180° C.
Claim 7
Dependent Claim
45 words
A process as claimed in claim 1, wherein, in the case of a polyethylene having a high density higher than 0.950 and a molecular weight equal to at least 200,000, the temperature of the cross-linking zone of said passageway is between 200° and 300° C.
Claim 8
Dependent Claim
42 words
A process as claimed in claim 1, wherein, in the case of a polyethylene having a high density higher than 0.950 and a molecular weight equal to at least 200,000, the pressure exerted on said mixture is between 500 and 1,800 kg/sq.cm.
Claim 9
Dependent Claim
134 words
A process for producing a hollow tubular product of cross-linked high-density polyethylene from an essentially powdered cross-linkable mixture comprising said high-density polyethylene and a cross-linking agent, comprising forcing said mixture into and through an elongate passageway which extends longitudinally along an axis and has an annular cross-sectional shape, by exerting a pressure on said mixture in a direction parallel to said axis while maintaining the cross-sectional shape and size of the whole of said mixture in said passageway constant and while maintaining an upstream part of said passageway relative to the direction of travel of said mixture at a temperature of 140°-200° C. and maintaining a downstream part of said passageway adjacent to said upstream part relative to the travel of said mixture at a temperature of 200°-300° C. to cross-link said high-density polyethylene.
Claim 10
Dependent Claim
134 words
A process for producing a hollow tubular product of cross-linked high-density polyethylene from an essentially powdered cross-linkable mixture comprising said high-density polyethylene and a cross-linking agent, comprising forcing said mixture into and through an elongate passageway which extends longitudinally along an axis and has an annular cross-sectional shape, by exerting a pressure on said mixture in a direction parallel to said axis while maintaining the cross-sectional shape and size of the whole of said mixture in said passageway constant and while maintaining an upstream part of said passageway relative to the direction of travel of said mixture at a temperature of 140°-200° C. and maintaining a downstream part of said passageway adjacent to said upstream part relative to the travel of said mixture at a temperature of 200°-300° C. to cross-link said high-density polyethylene.
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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) | 1981-11-20 | 1982-05-22 | 1982-11-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-11-20 | 1986-05-22 | 1986-11-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-11-20 | 1990-05-22 | 1990-11-21 | $7700.00 | Window Closed / Lapsed |