# US 9,435,972 B2 · Binder film for a fiber optic cable

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- Number: US 9,435,972 B2
- Document ID: US9435972B2
- Status: Granted
- Kind: B2
- Application number: 14/751,659
- Filed: 2015-06-26
- Published: 2015-10-15
- Granted: 2016-09-06
- Earliest claimed: 2012-09-26
- Assignees: Corning Optical Communications LLC
- Applicants: Corning Optical Communications LLC
- Inventors: Bradley Jerome Blazer; Rodney Maurice Burns; Julian Latelle Greenwood, III; Keith Aaron Greer; Warren Welborn McAlpine
- Web page: https://patentgrep.com/patent/US9435972B2

## CPC

- G02B 6/4486: {Protective covering}
- B29D 11/00721: {involving preforms for the manufacture of light guides}
- B29D 11/00875: {on light guides}
- G02B 6/441: {built up from sub-bundles (G02B6/4429, G02B6/4439, G02B6/4479 take precedence)}
- G02B 6/4413: {Helical structure}
- G02B 6/4416: {Heterogeneous cables}
- G02B 6/4431: {with provision in the protective covering, e.g. weak line, for gaining access to one or more fibres, e.g. for branching or tapping (break-out terminations G02B6/4471)}
- G02B 6/4434: {Central member to take up tensile loads}
- G02B 6/44384: {the means comprising water blocking or hydrophobic materials (G02B6/4439, G02B6/4479 take precedence)}
- G02B 6/4489: {of central supporting members of lobe structure}
- G02B 6/449: {Twisting}
- B29K 2023/065: {HDPE, i.e. high density polyethylene}
- B29K 2023/12: {PP, i.e. polypropylene}
- B29K 2995/0077: Yield strength; Tensile strength
- B29K 2995/0097: Thickness
- G02B 6/4411: {Matrix structure}
- G02B 6/4432: {with fibre reinforcements}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00)
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS

## Abstract

A sub-assembly of a fiber optic cable, the sub-assembly includes a central strength member, core elements wound about the central strength member in a stranded configuration, wherein the core elements comprise buffer tubes, filler rods, secondary strength members, and/or conductive wires, and a binder film overlaying the stranded core elements, the binder film comprising a polymeric material having a Young's modulus of 3 gigapascals or less such that the binder film constrains the core elements.

## Claims

### Claim 1

A sub-assembly of a fiber optic cable, the sub-assembly comprising:
a central strength member;
core elements wound about the central strength member in a stranded configuration, wherein the core elements comprise buffer tubes, filler rods, secondary strength members, and/or conductive wires; and
a binder film overlaying the stranded core elements, the binder film comprising a polymeric material having a Young's modulus of 3 gigapascals or less such that the binder film constrains the core elements.

### Claim 2 (depends on 1)

The sub-assembly of claim 1, wherein the binder film is in tension, and wherein tension in the binder film holds the core elements against the central strength member, opposing outwardly transverse deflection of the core elements.

### Claim 3 (depends on 1)

The sub-assembly of claim 1, wherein the binder film is formed from a thermoplastic.

### Claim 4 (depends on 3)

The sub-assembly of claim 3, wherein the binder film is 0.2 millimeters or less in thickness, thereby facilitating rapid cooling of the binder film during manufacturing so that the binder film may quickly hold the core elements.

### Claim 5 (depends on 4)

The sub-assembly of claim 4, wherein the binder film is continuous lengthwise at least 10 meters.

### Claim 6 (depends on 5)

The sub-assembly of claim 5, wherein the binder film is watertight.

### Claim 7 (depends on 6)

The sub-assembly of claim 6, wherein the buffer tubes include a water-blocking element comprising a super-absorbent polymer, and wherein the central strength member is dielectric and comprises a rod.

### Claim 8

A fiber optic cable, comprising:
a central strength member;
core elements wound about the central strength member in a stranded configuration wherein the core elements comprise buffer tubes, filler rods, secondary strength members, and/or conductive wires;
a binder film overlaying and surrounding the stranded core elements, wherein the binder film is 0.5 millimeters or less in thickness and comprises a polymeric material having a Young's modulus of 3 gigapascals or less; and
a jacket surrounding the binder film, wherein the jacket thicker than the binder film.

### Claim 9 (depends on 8)

The fiber optic cable of claim 8, wherein the thickness of the binder film is less than a tenth of the maximum cross-sectional dimension of the fiber optic cable.

### Claim 10 (depends on 9)

The fiber optic cable of claim 9, wherein the binder film is 0.2 millimeters or less in thickness, thereby facilitating rapid cooling of the binder film during manufacturing so that the binder film quickly holds the core elements.

### Claim 11 (depends on 9)

The fiber optic cable of claim 9, wherein the jacket adjoins the binder film.

### Claim 12 (depends on 11)

The fiber optic cable of claim 11, wherein the binder film and the jacket both comprise polyethylene.

### Claim 13 (depends on 12)

The fiber optic cable of claim 12, wherein at least 70% of the binder film by weight consists of polyethylene.

### Claim 14

A method of manufacturing a sub-assembly of a fiber optic cable on a manufacturing line, comprising steps of:
stranding core elements around a central strength member, the core elements comprising buffer tubes, filler rods, secondary strength members, and/or conductive wires;
extruding a binder film to surround the core elements; and
opposing torque induced by the stranded core elements with equipment positioned in close proximity to a closing point of the core elements on the manufacturing line where the core elements come together from the stranding step to contact one another and/or the central strength member in the stranded configuration, thereby limiting unwinding of the stranded core elements as the binder film cools and shrinks to constrain the core elements.

### Claim 15 (depends on 14)

The method of claim 14, further comprising guiding the core elements through an extrusion crosshead with a nose piece.

### Claim 16 (depends on 15)

The method of claim 15, wherein the stranding step further includes stranding the core elements by extending the nose piece through the crosshead and into a space surrounded by an extrudate cone of the binder film.

### Claim 17 (depends on 15)

The method of claim 15, wherein the equipment opposing the torque is a caterpuller, and wherein the caterpuller is located within 100 millimeters of a release point of the nose piece.

### Claim 18 (depends on 14)

The method of claim 14, wherein the equipment opposing the torque is a caterpuller, and wherein the caterpuller is located within 100 millimeters of the closing point of the core elements.

### Claim 19 (depends on 18)

The method of claim 18, wherein the extruding step is such that the binder film is applied immediately after the core elements are stranded.

### Claim 20 (depends on 14)

The method of claim 14, further comprising providing a water-blocking element in the buffer tubes.