US4138462A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing cross-linked moulded objects from cross-linkable polymeric materials
Assignee: NKT AS
•
Filing: 1976-04-14
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Granted: 1979-02-06
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Expires: 1996-04-14
Abstract
Abstract The cross-linking of a moulded object based on polymeric materials is effected by heating the object in the presence of a liquid medium containing one or more peroxides under conditions that cause penetration, and the heating is continued at increasing temperatures to cause a homogeneous cross-linking. Employable peroxides are substantially stable under the first heating step but are cleaved into free radicals during the second heating step, at least the cross-linking step being carried out with the object enclosed in a liquid of approximately the same density as the polymeric material.
Inventors
- 👤 Francesco P. Procida
- 👤 Svend S. Pedersen
- 👤 Peter Carstensen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 06:58
CPC Classifications
C; C08; C08J; C08J7/00; C08J7/12; C08J3/00; C08J3/24
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
130 words
A method for cross-linking a shaped article which is in the form of a cable, tube, slab or profile made of high density polyethylene whereby the article is not deformed during the process which comprises (a) immersing said article in a heated aqueous liquid which contains a peroxide cross-linking agent whereby said cross-linking agent diffuses into the article wherein the time of immersion is sufficient to allow the desired depth of a penetration and the temperature is high enough to effect the desired rate of diffusion and low enough so that cross-linking can be kept low or eliminated. (b) subsequently heating said article at a temperature at which the cross-linking will occur in an aqueous liquid whose density at that temperature is approximately the same as that of the article.
Claim 2
Independent Claim
130 words
A method for cross-linking a shaped article which is in the form of a cable, tube, slab or profile made of high density polyethylene whereby the article is not deformed during the process which comprises (a) immersing said article in a heated aqueous liquid which contains a peroxide cross-linking agent whereby said cross-linking agent diffuses into the article wherein the time of immersion is sufficient to allow the desired depth of a penetration and the temperature is high enough to effect the desired rate of diffusion and low enough so that cross-linking can be kept low or eliminated. (b) subsequently heating said article at a temperature at which the cross-linking will occur in an aqueous liquid whose density at that temperature is approximately the same as that of the article.
Claim 3
Dependent Claim
21 words
A method according to claim 1 wherein the liquid of the cross-linking step is the same as the peroxide containing liquid.
Claim 4
Dependent Claim
35 words
A method according to claim 1 wherein the liquid containing the peroxide is replaced after the desired depth of diffusion has been reached for the cross-linking step, by an aqueous liquid which contains no peroxide.
Claim 5
Dependent Claim
21 words
A method according to claim 1, wherein said shaped article contains substantially no cross-linking agent prior to said immersing said article.
References Cited (Backward Citations)
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US3051992A
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US3576933A
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US3479446A
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US3720744A
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US3773885A
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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) | 1982-02-05 | 1982-08-07 | 1983-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-02-05 | 1986-08-07 | 1987-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-02-05 | 1990-08-07 | 1991-02-06 | $7700.00 | Window Closed / Lapsed |