Extruded buffer tubes comprising polyolefin resin based color concentrates for use in fiber optic cables

• US 6,421,486 B1
• Filed: 07/01/1999
• Issued: 07/16/2002
• Est. Priority Date: 07/01/1999
• Status: Expired due to Term

• Current Assignee: Furukawa Electric North America Incorporated (Furukawa Electric Company Limited)
• Original Assignee: Fitel USA Corporation
• Inventors: Siddhamalli, Sridhar K., Daneshvar, Omid
• Primary Examiner(s): Ullah, Akm E.
• Application Number:
  US09/346,192
• Time in Patent Office: 1,111 Days
• Field of Search: 385/100-109, 385/147
• US Class Current: 385/109
• CPC Class Codes: G02B 6/441 built up from sub-bundles G02B6/4429, G02B6/4439, G02B6/4479 take precedence
• CPC Class Codes: G02B 6/4482 Code or colour marking

Abstract

An optical fiber cable with a plurality of buffer tubes wherein the buffer tubes each encase a bundle of optical fibers. The buffer tubes are color-coded by means of mixing a buffer tube material with a colorant before or during the extrusion process. A polyolefin is used as the base resin for the color concentrate resulting in increased let down ratios. By using less colorant to deliver desired amount of pigment to the buffer tube, cost savings and enhanced processability are achieved.

Claims

1. An optical fiber cable having at least one buffer tube encasing a plurality of optical fibers, wherein the buffer tube comprises a mixture of:

a buffer tube material; and

a polyolefin resin based color concentrate, wherein said polyolefin resin based color concentrate is selected from the group consisting of linear low density polyethylene, polyethylene, polypropylene, ethylene copolymers, ethylene terpolymers, propylene copolymers, and propylene terpolymers.

2. The buffer tube of claim 1, wherein the buffer tube material is selected from the group consisting of polybutylene terephthlate, polyester elastomer, fluoropolymer, acetal resin, nylon, and polycarbonate.

3. The buffer according to claim 1, wherein the ratio of the buffer tube material to the polyolefin resin basin color concentrate is approximately between 100:

1 to 500;

1 parts by weight.

4. An optical fiber cable having at least one buffer tube encasing a plurality of optical fibers, the buffer tube being made by the process of:

heating a buffer tube material and a polyolefin resin based color concentrate in an extruder, wherein said polyolefin resin based color concentrate is selected from the group consisting of linear low density polyethylene, polyethylene, polypropylene, ethylene, copolymers, ethylene terpolymers, propylene copolymers, and propylene terpolymers; and

forming the buffer tube from the heated buffer tube material and polyolefin resin based color concentrate utilizing the extruder.

5. The buffer tube material made in accordance with the process of claim 4 wherein the buffer tube material is selected from the group consisting of polybutylene terephthlate, polyester elastomer, fluoropolymer, acetal resin, nylon, and polycarbonate.

6. The buffer tube made in accordance with the process of claim 4, wherein the ratio of the buffer tube material to the polyolefin resin basin color concentrate is approximately between 100:

1 to 500;

1 parts by weight.

7. The buffer tube made in accordance with the process of claim 4, further comprising the step of mixing the buffer tube material and the polyolefin resin based color concentrate.