Heat-recoverable sealing article with self-contained heating means and method of sealing a splice therewith

• US 4,085,286 A
• Filed: 08/04/1975
• Issued: 04/18/1978
• Est. Priority Date: 09/27/1974
• Status: Expired due to Term

• Current Assignee: Raychem Corporation (TE Connectivity Limited)
• Original Assignee: Raychem Corporation (TE Connectivity Limited)
• Inventors: Diaz, Stephen Hunter, Horsma, David August
• Primary Examiner(s): Askin, Laramie E.
• Application Number:
  US05/601,344
• Time in Patent Office: 988 Days
• Field of Search: 174/DIG. 8, 174/84 R, 174/87, 174/88 R, 174/91-93, 174/138 F, 174/35 R, 174/35 C, 339/DIG. 1, 53/30 S, 156/49, 156/53, 156/54, 156/85, 156/86, 156/272, 156/275, 219/331, 219/504, 219/505, 264/25, 264/27, 264/230, 264/342 R, 264/DIG. 71, 285/381, 285/423, 285/DIG. 10
• US Class Current: 174/92
• CPC Class Codes: B29C 61/0608 characterised by the configuration or structure of the preforms
• CPC Class Codes: B29C 61/0616 layered or partially layered preforms, e.g. preforms with layers of adhesive or sealing compositions B29C61/0625 and B29C61/065 take precedence
• CPC Class Codes: B29C 61/0625 Preforms comprising incorporated or associated heating means
• CPC Class Codes: B29C 61/0641 Clips for dividing preforms or forming branch-offs clips in general F16B2/20
• CPC Class Codes: B29C 61/10 by bending plates or sheets in general B29C53/36
• CPC Class Codes: B29K 2995/0005 Conductive
• CPC Class Codes: F16L 47/20 based principally on specific properties of plastics
• CPC Class Codes: F16L 47/22 using shrink-down material
• CPC Class Codes: F16L 57/00 Protection of pipes or objects of similar shape against external or internal damage or wear protection under water F16L1/123; supporting of pipes inside other pipes or sleeves F16L7/00; used in connection with end fittings of hoses F16L35/00; protection thereof during transport B65D59/00
• CPC Class Codes: H02G 15/10 protected by boxes, e.g. by distribution, connection or junction boxes
• CPC Class Codes: Y10S 174/08 Shrinkable tubes
• CPC Class Codes: Y10S 428/913 Material designed to be responsive to temperature, light, moisture

Abstract

A heat recoverable article is so configured that it can be positioned around a pipe or cable joint or splice which it is desired to encapsulate or seal. Means for sealing a splice involving a plurality of cables of the same or varying sizes are provided. The article includes a closure means for holding the article together after it has been positioned around the splice to be sealed. In a preferred embodiment, the inner surface of the article contains a heat activated adhesive or sealant to environmentally encapsulate the splice and the outer layer of the article is a heat recoverable insulating material. In a particularly preferred embodiment, the article has self-contained heating means, which heating means comprises a polymeric material having dispersed therein a conductive filler, said heating means exhibiting a positive temperature coefficient of resistance so as to render it self-regulating.

Claims

1. A heat recoverable article having self-contained heating means comprising a conductive polymeric composition, said polymeric composition being capable of conducting sufficient current there through at a given voltage and exhibiting sufficient resistance to give a heat output capable of causing the heat unstable material to recover to its original form, said conductive polymeric composition being so configured that its length and width are substantially greater than its thickness and said conductive polymeric composition being adapted for connection to a power source such that the current will flow through its thickness, said article being further characterized as comprising a polymeric material which has been dimensionally changed from an original heat stable form to a heat unstable form capable of moving in the direction of its original form upon the application of sufficient heat and being so configured that it can be positioned around a splice to be sealed.

2. The article of claim 1 wherein the heat unstable polymeric material comprises a polymeric component of the conductive polymeric composition.

3. The article of claim 1 wherein the conductive polymeric composition comprises a polymer having dispersed therein conductive carbon particles.

4. The article of claim 1 wherein there is affixed to the surface of the article which is to be disposed towards the splice to be sealed a container of desiccant, the water vapor transmission characteristics of said container relative to that of the article for sealing a splice being such as to maintain the relative humidity at less than about 30% within the cavity formed when said article is caused to heat recover around a splice.

5. An article according to claim 1 wherein said polymeric composition exhibits a positive temperature coefficient of resistance.

6. A heat recoverable tubular article for sealing joints having self-contained and self-regulating heating means comprising a conductive polymeric heating composition exhibiting a positive temperature coefficient of resistance and having sufficient heating capacity when connected to an electrical power source, to cause at least a heat recoverable portion of the tubular article to recover around and seal a joint therebeneath.

7. The article of claim 6 having on its inner surface a heat activatable adhesive or sealant to further seal the joint.

8. An article according to claim 6 wherein said conductive polymeric composition is so configured that its length and width are substantially greater than its thickness and said conductive polymeric composition is adapted for connection to said power source such that current will flow through its thickness.

9. A heat recoverable closure member having self-contained and self-regulating heating means and being adapted to heat recover around and seal a splice comprising a conductive polymeric heating composition, said composition exhibiting a positive temperature coefficient of resistance and having sufficient heating capacity when connected to an electrical power source to cause a heat recoverable portion of the closure member to heat recover, said closure member having first and second edges adapted to be brought together to form a tubular member and means for engaging said edges, said means maintaining said edges together during heat recovery.

10. The closure member of claim 9 wherein the polymeric heating composition comprises a crystalline thermoplastic material having dispersed therein particulate carbon black.

11. The closure member of claim 9 having on its inner surface a heat activatable adhesive or sealant to further seal said splice.

12. The closure member of claim 9 wherein the tubular member so formed is adapted at its end to individually recover around and seal a plurality of cables, and said tubular member having a central portion adapted to seal a splice of the plurality of cables.

13. The closure member of claim 12 having positioned at the central inner portion of said tubular member a rigid, dimensionally stable member adapted to be positioned around a splice of the plurality of cables whereby upon heat recovery, the central portion of the tubular member conforms to the shape of said rigid member and the end of said tubular member recovers to the diameters of said cables.

14. A closure member according to claim 9 wherein said conductive polymeric composition is so configured that its length and width are substantially greater than its thickness and said conductive polymeric composition is adapted for connection to said power source such that current will flow through its thickness.

15. A heat recoverable closure member having self-contained heating means and being adapted to heat recover around a splice joining a plurality of members comprising a conductive polymeric heating composition having sufficient heating capacity when connected to an electrical power source to cause the closure member to heat recover, said closure member having first and second edges which can be brought together to form a tubular member and a means for engaging said edges, the means maintaining said edges together during heat recovery, said closure member having on its inner surface which is to contact the members joined by the splice activatable material suitable for bonding and sealing the members joined by the splice, and the closure having member at at least one end of the tubular member formed with a plurality of individual passages through which a plurality of member joined by the splice may be inserted, said plurality of passages recovering around and sealing the plurality of member joined by the splice upon heat recovery of the closure member.

16. The closure member of claim 15 having a central portion adapted to seal the splice of the plurality of members, and having at the central inner portion of said tubular member a rigid dimensionally stable member adapted to be positioned around the splice of the plurality of members whereby upon heat recovery, the central portion of the tubular member conforms to the shape of said rigid member.

17. A closure member according to claim 15 wherein said conductive polymeric composition is so configured that its length and width are substantially greater than its thickness and said conductive polymeric composition is adapted for connection to said power source such that current flows through its thickness.

18. A closure member according to claim 17 wherein said plural passages are defined by a plurality of heat recoverable folds in opposing portions of said member when said edges are joined.

19. A closure member according to claim 18 having rigid members affixed thereto outboard said folded portions.

20. A heat recoverable closure article having self-contained and self-regulating heating means and being adapted to be heat recovered around a joint comprising

(a) a first layer of conductive polymeric material exhibiting a positive temperature coefficient of resistance,

(b) at least one additional layer of conductive polymeric material adjacent a surface of said first layer exhibiting substantially constant resistance upon change in temperature to give a substantially constant wattage output at a given voltage,

(c) electrodes positioned adjacent opposite surfaces of said first layer such that an applied current will flow through the thickness of said first layer;

and at least one of said layers being heat recoverable, said layers being adapted so that the recovery of said heat recoverable layer upon the application of heat results in recovery of the other of said layers.

21. The closure article of claim 20 wherein a constant wattage output layer is positioned adjacent both surfaces of said first layer and said constant wattage output layers are in contact with said electrodes.

22. The closure article of claim 20 having a layer of electrically insulating material, and an inner layer of heat activatable adhesive, said adhesive being activated at the operating temperature of the heating means;

and the closure article having first and second edges adapted to be brought together to form a tubular member and a means for engaging said edges, said means maintaining said edges together during heat recovery.

23. The closure article of claim 22 wherein the tubular member so formed is adapted at its end to individually recover around and seal a plurality of cables, and said tubular member having a central portion adapted to seal a splice of the plurality of cables.

24. The closure article of claim 23 having positioned at the central inner portion of said tubular member a rigid, dimensionally stable member adapted to be positioned around a splice of the plurality of cables whereby upon heat recovery, the central portion of the tubular member conforms to the shape of said rigid member and the end of said tubular member adapted to individually recover around and seal a plurality of cables recovers to the diameters of said cables.

25. The closure article member of claim 22 wherein the insulating layer is heat recoverable.

26. The closure article of claim 20 wherein the positive temperature coefficient of resistance layer comprises the heat recoverable layer.

27. The closure article of claim 20 wherein the heat recoverable layer comprises an additional adhesive layer, said adhesive being activatable at the heating temperature.

28. An article according to claim 20 that is tubular.

29. A process of heat sealing a joint between members without external heating means comprising the steps of:

positioning around said joint to be sealed a heat-recoverable article having self-contained and self-regulating heating means comprising

(a) a first layer of conductive polymeric material exhibiting a positive temperature coefficient of resistance,

(b) a second layer of polymeric material adjacent a surface of said first layer having dispersed therein a conductive filler, said layers exhibiting substantially constant resistance upon change in temperature to give a substantially constant wattage output at a given voltage,

(c) electrodes positioned adjacent opposite surfaces of said first layer such that an applied current will flow through the thickness of said first layer,

(d) a third layer of electrically insulating material,

(e) an inner layer of heat activatable material, said material being activated at the operating temperature of the heating article to bond to the members to be sealed, at least one of said layers being heat recoverable at the operating temperature of the article; and

applying sufficient current to the electrodes to cause recovery of the heat recoverable materials and activation of the adhesive.

30. The process of claim 29 wherein the article is positioned around the joint by wrapping the article around said joint and engaging the edges of said article with a means sufficient to maintain said edges together during heat recovery.

31. A closure article, at least a portion of which is heat recoverable, said closure article having first and second edges adapted to be brought together to form a tubular structure having a central cavity portion and means for maintaining said edges together during heat recovery, the tubular structure so formed having plural openings at at least one end, said openings comprising heat recoverable folds in opposing portions of said article when brought together to form said tubular structure, being adapted to heat recover around and seal a plurality of cables to be inserted therein and a rigid dimensionally stable member disposed adjacent the inner surface of that portion of the tubular structure defining said cavity.

32. An article according to claim 31 wherein rigid members are affixed to said article outboard said folds.

33. A closure article comprising first and second members adapted to be brought together to form a tubular structure having a central cavity portion and plural openings at at least one end thereof, said openings being heat recoverable and adapted to seal a plurality of cables to be inserted therein upon the application of heat, said first member being heat recoverable and said second member being non-heat recoverable, said heat recoverable member having plural folds in a heat recoverable portion thereof defining said openings, said folds being supported by said non-heat recoverable member.

34. A closure article according to claim 33 wherein rigid members are affixed to said first member outboard said folds.

35. A closure article according to claim 34 having self-contained heating means comprising a conductive polymer composition and wherein said heat-recoverable folds comprise said conductive polymer composition.

36. A closure article according to claim 34 having self-contained and self-regulating heating means comprising a conductive polymer composition exhibiting a positive temperature coefficient of resistance and wherein said heat-recoverable folds comprise said conductive polymer composition.

37. A closure article according to claim 34 wherein said non-heat recoverable member is provided with plural ridges for insertion between said folds.

38. A closure article having self-contained and self-regulating heating means comprising first and second members adapted to be brought together to form a tubular structure having a central cavity portion and plural openings at at least one end thereof, said openings being heat recoverable and adapted to seal a plurality of cables to be inserted therein, said first member being heat recoverable and said second member being non-heat recoverable, said heat recoverable member having plural folds in a heat recoverable portion thereof defining said openings, said folds being supported on said non-heat recoverable member, said folds comprising:

(a) a first layer of conductive polymeric material exhibiting a positive temperature coefficient of resistance,

(b) at least one additional layer of conductive polymeric material adjacent a surface of said first layer exhibiting substantially constant resistance upon change in temperature to give a substantailly constant wattage output at a given voltage, and

(c) electrodes positioned adjacent opposite surfaces of said first layer such that an applied current will flow through the thickness of said first layer; and

at least one of said layers being heat recoverable, said layers being adapted so that the recovery of said heat recoverable layer upon the application of heat results in recovery of the other of said layers.

39. The closure article of claim 38 wherein a constant wattage output layer is positioned adjacent both surfaces of said first layer and said constant wattage output layers are in contact with said electrodes.

40. The closure article of claim 38 wherein the positive temperature coefficient of resistance layer comprises the heat recoverable layer.

41. The closure article of claim 38 wherein the heat recoverable layer comprises an additional adhesive layer, said adhesive being activatable at the heating temperature.