Patent US4251304A successfully refreshed from Google Patents.
US4251304A
Expired / Lapsed
US
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Heat-recoverable articles and their use
Assignee: Raychem Corp
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Filing: 1979-04-19
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Granted: 1981-02-17
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Expires: 1999-04-19
Abstract
Abstract A method of making a composite structure comprising an elongate substrate, especially an insulated electrical cable, and a covering member which has been heat-recovered and sealed around the substrate. A heat-recoverable article of a cross-linked crystalline polymer composition which transmits 5-50% of infra-red radiation incident thereon is placed around a substrate whose exterior is composed of a polymeric composition which is at most lightly cross-linked, which absorbs infra-red radiation and which has a crystalline melting point below that of the heat-recoverable article. The assembly is exposed to infra-red radiation such that the heat-recoverable article is heated to its recovery temperature and the exterior of the substrate is heated to its crystalline melting point, preferably before it is contacted by said article as it recovers. In this way an excellent seal can be created between the substrate and the recovered article without the need for any auxiliary fusible material such as a hot melt adhesive.
Inventors
- 👤 Bruce D. Campbell
- 👤 Eugene F. Lopez
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:23
CPC Classifications
H; H02; H02G; H02G15/00; H02G15/08; H02G15/18; H02G15/1806; B; B29; B29C; B29C61/00; B29C61/003; H02G15/02; H02G15/04; H02G15/043; B29K; B29K2023/00; Y; Y10; Y10S; Y10S174/00; Y10S174/08; Y10T; Y10T428/00; Y10T428/13; Y10T428/1328; Y10T428/1331
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
276 words
A method of covering a substrate with a covering member which is sealed around at least one section of said substrate with a covering member which is sealed around at least one section of said substrate, which method comprises (1) providing an assembly comprising a substrate and a covering member, said covering member comprising a heat-shrinkable band portion which has a closed cross-section and passes around at least one section of said substrate; said section comprising an exterior wall portion composed of a first crystalline polymeric composition which has a gel fraction of at most 0.3 and a crystalline melting point T 1 and in which there is dispersed an absorptive material which absorbs electromagnetic radiation; and said band portion comprising a heat-shrinkable interior wall portion composed of a second crystalline polymeric composition which has a gel fraction of at least 0.3 and a crystalline melting point T 2 equal to at least (T 1 +5)° C. and which absorbs electromagnetic radiation; and (2) exposing the exterior of said heat-shrinkable band portion to electromagnetic radiation, said radiation and said first and second polymeric compositions being such that said band portion absorbs a fraction of said radiation which heats said band portion to its shrinkage temperature and transmits a fraction of said radiation, at least portion of said transmitted fraction being absorbed by said exterior wall portion of the substrate and heating said exterior wall portion of the substrate to a temperature which is at least equal to its crystalline melting point T 1 , whereby said interior wall portion of the covering member shrinks into direct sealing contact with said exterior wall portion of the substrate.
Claim 2
Independent Claim
276 words
A method of covering a substrate with a covering member which is sealed around at least one section of said substrate with a covering member which is sealed around at least one section of said substrate, which method comprises (1) providing an assembly comprising a substrate and a covering member, said covering member comprising a heat-shrinkable band portion which has a closed cross-section and passes around at least one section of said substrate; said section comprising an exterior wall portion composed of a first crystalline polymeric composition which has a gel fraction of at most 0.3 and a crystalline melting point T 1 and in which there is dispersed an absorptive material which absorbs electromagnetic radiation; and said band portion comprising a heat-shrinkable interior wall portion composed of a second crystalline polymeric composition which has a gel fraction of at least 0.3 and a crystalline melting point T 2 equal to at least (T 1 +5)° C. and which absorbs electromagnetic radiation; and (2) exposing the exterior of said heat-shrinkable band portion to electromagnetic radiation, said radiation and said first and second polymeric compositions being such that said band portion absorbs a fraction of said radiation which heats said band portion to its shrinkage temperature and transmits a fraction of said radiation, at least portion of said transmitted fraction being absorbed by said exterior wall portion of the substrate and heating said exterior wall portion of the substrate to a temperature which is at least equal to its crystalline melting point T 1 , whereby said interior wall portion of the covering member shrinks into direct sealing contact with said exterior wall portion of the substrate.
Claim 3
Dependent Claim
38 words
A method according to claim 1 wherein said radiation is infra-red radiation and said heat-shrinkable band portion of the covering member, when exposed to radiation having a wavelength of 1.15 microns, transmits 5 to 40% of the radiation.
Claim 4
Dependent Claim
22 words
A method according to claim 1 wherein said first polymeric composition comprises an ethylene polymer having a density of 0.90 to 0.94.
Claim 5
Dependent Claim
13 words
A method according to claim 3 wherein said density is 0.91 to 093.
Claim 6
Dependent Claim
19 words
A method according to claim 3 wherein said ethylene polymer comprises at least 90% by weight of ethylene units.
Claim 7
Dependent Claim
32 words
A method according to claim 1 wherein said first polymeric composition has a gel fraction of at most 0.2 and said second polymeric composition has a gel fraction of at least 0.4.
Claim 8
Dependent Claim
16 words
A method according to claim 6 wherein said first polymeric composition is substantially free from cross-linking.
Claim 9
Dependent Claim
18 words
A method according to claim 1 wherein T 2 is equal to at least (T 1 +10)° C.
Claim 10
Dependent Claim
37 words
A method according to claim 1 wherein the exterior of said exterior wall portion of the substrate is heated to a temperature of at least T 1 before said band portion is heated to its shrinkage temperature.
Claim 11
Dependent Claim
30 words
A method according to claim 9 wherein the said exterior wall portion is heated to a temperature of at least T 1 to a depth of at least 0.0005 inch.
Claim 12
Dependent Claim
30 words
A method according to claim 9 wherein said exterior wall portion is heated to a temperature of not more than (T 1 -5)° C. at a depth of 0.075 inch.
Claim 13
Dependent Claim
29 words
A method according to claim 9 wherein said exterior wall portion is heated to a temperature of at least T 1 to a depth of 0.0005 to 0.005 inch.
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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) | 1984-02-17 | 1984-08-18 | 1985-02-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-17 | 1988-08-18 | 1989-02-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-17 | 1992-08-18 | 1993-02-17 | $7700.00 | Window Closed / Lapsed |