Optical fiber cable provided with stabilized waterblocking material

• US 5,285,513 A
• Filed: 11/30/1992
• Issued: 02/08/1994
• Est. Priority Date: 11/30/1992
• Status: Expired due to Term

• Current Assignee: Furukawa Electric North America Incorporated (Furukawa Electric Company Limited)
• Original Assignee: AT&T, Inc.
• Inventors: Kaufman, Stanley, Sheu, Jim J.
• Primary Examiner(s): Lee, John D.
• Time in patent office: 435 Days
• Field of Search: 385/100, 385/102, 385/105, 385/109, 385/110, 385/141, 523/173, 252/194, 252/302, 252/304
• US Class Current: 385/109
• CPC Class Codes: G02B 6/4494 provided with water blocking or hydrophobic materials G02B6/4439, G02B6/4479 take precedence

Abstract

A cable of this invention includes a core comprising a plurality of coated optical fibers and a filling composition of matter which is disposed about the fibers. Typically, the fibers and the filling material are diposed within a tubular member which is disposed within a sheath system. The sheath system include longitudinally extending strength members and a plastic jacket. The filling composition which fills interstices in the core is one which includes an oil constituent which is a relatively high molecular weight aliphatic hydrocarbon. The aliphatic hydrocarbon is a synthetic oil such as polyalphaolefin or mineral oil. A relatively large percent by weight of an antioxidant system is used to prevent thermal oxidative degradation of the filling material as well as of materials in contact with the filling material. Advantageously, for stabilization and metal deactivation, the composition includes zinc dialkyldithiophosphate or diaryldithiophosphate. A styreneethylene propylene copolymer is also included in order to reduce oil separation of the filling material. A fumed silica is used to impart gel properties to the material.

Claims

1. An optical fiber cable, which comprises:

a core comprising at least one optical fiber transmission medium;

a sheath system which is disposed about said core; and

a filling composition of matter which is disposed about the transmission medium in said core, said filling composition of matter comprising a hydrocarbon, a block copolymer, a colloidal filler and an antioxidant system which includes a hindered phenol sulfide in combination with a metal deactivator selected from the group consisting of dialkyldithiophosphates and diaryldithiophosphates.

2. The optical fiber cable of claim 1, wherein said antioxidant system comprises about 1.3 percent by weight of said filling composition.

3. The optical fiber cable of claim 1, wherein said hydrocarbon is aliphatic.

4. The optical fiber cable of claim 3, wherein said aliphatic hydrocarbon comprises a synthetic oil.

5. The optical fiber cable of claim 4, wherein said synthetic oil is selected from the group consisting of polyalphaolefin, polybutene and polypropene.

6. The optical fiber cable of claim 3, wherein said aliphatic hydrocarbon comprises a mineral oil.

7. A composition of matter for filling optical fiber cables comprising a hydrocarbon, a block copolymer, a colloidal filler and an antioxidant system which includes a hindered phenol sulfide in combination with a metal deactivator selected from the group consisting of dialkyldithiosphates and diaryldithiophosphates.

8. The composition of matter of claim 7, wherein said antioxidant system comprises about 1.3 percent by weight of said filling composition.

9. The composition of matter of claim 7, wherein said hydrocarbon is aliphatic.

10. The composition of matter of claim 9, wherein said aliphatic hydrocarbon comprises a synthetic oil.

11. The composition of matter of claim 10, wherein said synthetic oil is selected from the group consisting of polyalphaolefin, polybutene and polypropene.

12. The composition of matter of claim 9, wherein said aliphatic hydrocarbon comprises a mineral oil.