Low shrink telecommunications cable and methods for manufacturing the same

• US 20060159407A1
• Filed: 01/18/2005
• Published: 07/20/2006
• Est. Priority Date: 01/18/2005
• Status: Active Grant

• Current Assignee: CommScope Technologies, LLC (CommScope Holding Company, Inc.)
• Original Assignee: ADC Telecommunications Incorporated (TE Connectivity Limited)
• Inventors: Kachmar, Wayne M.
• Granted Patent: US 7,379,642 B2
• Time in Patent Office: Days
• US Class Current: 385/102
• CPC Class Codes: G02B 6/441 built up from sub-bundles G02B6/4429, G02B6/4439, G02B6/4479 take precedence
• CPC Class Codes: G02B 6/4429 Means specially adapted for strengthening or protecting the cables
• CPC Class Codes: G02B 6/443 Protective covering
• CPC Class Codes: G02B 6/4432 with fibre reinforcements
• CPC Class Codes: G02B 6/4436 Heat resistant
• CPC Class Codes: G02B 6/4486 Protective covering
• CPC Class Codes: Y10T 428/29 Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
• CPC Class Codes: Y10T 428/2933 Coated or with bond, impregnation or core
• CPC Class Codes: Y10T 428/2947 Synthetic resin or polymer in plural coatings, each of different type

Abstract

The present disclosure relates to a telecommunications cable having a layer constructed to resist post-extrusion shrinkage. The layer includes a plurality of discrete shrinkage-reduction members embedded within a base material. The shrinkage-reduction members can be made of a liquid crystal polymer. The disclosure also relates to a method for manufacturing telecommunications cables having layers adapted to resist post-extrusion shrinkage.

Claims

1. A telecommunications cable comprising:

at least one member for carrying a telecommunications signal; and

a layer surrounding the member, the layer including a thermoplastic base material and a liquid crystal polymer embedded within the base material for resisting shrinkage of the base material, the liquid crystal polymer constituting less than 2% of the layer by weight.

2. The telecommunications cable of claim 1, wherein the at least one member includes at least one optical fiber.

3. The telecommunications cable of claim 2, wherein the layer forms an outer jacket that surrounds the optical fiber.

4. The telecommunications cable of claim 2, wherein the layer forms a buffer layer that surrounds the optical fiber.

5. The telecommunications cable of claim 1, further comprising a strength layer for providing tensile reinforcement to the telecommunications cable.

6. The telecommunications cable of claim 5, wherein the strength layer includes aramid yarn.

7. The telecommunications cable of claim 1, wherein the liquid crystal polymer forms a plurality of discrete, elongated shrink-reduction members that are embedded in the base material.

8. The telecommunications cable of claim 7, wherein at least some of the shrink-reduction members have lengths in the range of 0.2-100 mm.

9. The telecommunications cable of claim 8, wherein a majority of the shrink-reduction members have lengths in the range of 10-40 mm.

10. The telecommunications cable of claim 1, wherein the layer shrinks less than 3% in length when tested separately from the member for carrying a telecommunications signal by exposing the layer to 110 degrees Celsius for 2 hours.

11. The telecommunications cable of claim 1, wherein the layer shrinks less than 2% in length when tested separately from the member for carrying a telecommunications signal by exposing the layer to 110 degrees Celsius for 2 hours.

12. The telecommunications cable of claim 1, wherein the layer shrinks less than 1% in length when tested separately from the member for carrying a telecommunications signal by exposing the layer to 110 degrees Celsius for 2 hours.

13. A telecommunications cable comprising:

at least one member for carrying a telecommunications signal; and

a layer surrounding the member, the layer including a thermoplastic base material and a plurality of discrete shrinkage-reduction members embedded within the thermoplastic base material, at least some of the shrinkage-reduction members having lengths in the range of 0.2-100 mm, and the shrinkage-reduction members including a liquid crystal polymer.

14. The telecommunications cable of claim 13, wherein the at least one member includes at least one optical fiber.

15. The telecommunications cable of claim 14, wherein the layer forms an outer jacket that surrounds the optical fiber.

16. The telecommunications cable of claim 14, wherein the layer forms a buffer layer that surrounds the optical fiber.

17. The telecommunications cable of claim 13, further comprising a strength layer for providing tensile reinforcement to the telecommunications cable.

18. The telecommunications cable of claim 17, wherein the strength layer includes aramid yarn.

19. The telecommunications cable of claim 13, wherein the layer shrinks less than 3% in length when tested separately from the member for carrying a telecommunications signal by exposing the layer to 110 degrees Celsius for 2 hours.

20. The telecommunications cable of claim 13, wherein the layer shrinks less than 2% in length when tested separately from the member for carrying a telecommunications signal by exposing the layer to 110 degrees Celsius for 2 hours.

21. The telecommunications cable of claim 13, wherein the layer shrinks less than 1% in length when tested separately from the member for carrying a telecommunications signal by exposing the layer to 110 degrees Celsius for 2 hours.

22. A telecommunications cable comprising:

an optical fiber;

a strength layer for providing the cable with tensile reinforcement; and

an outer jacket surrounding the optical fiber and the strength layer, the jacket including a thermoplastic base material and a plurality of discrete shrinkage-reduction members embedded within the thermoplastic base material, the shrinkage-reduction members including a liquid crystal polymer.

23. The telecommunications cable of claim 22, wherein the strength layer includes aramid yarn.

24. A method for manufacturing a fiber optic cable comprising:

mixing a base material and a shrinkage reduction material in an extruder;

extruding the mixture of the base material and the shrinkage reduction material through an extrusion die;

reshaping the shrinkage reduction material into a plurality of elongated reinforcing members as the base material and the shrinkage reduction material are extruded through the extrusion die, wherein the shrinkage reduction members include a plurality of discrete shrinkage-reductions members each having a length that coincides with only a relatively small segment of a total length of the fiber optic cable.