Method of Splitting Fiber Tows

Patent metadata

Field	Value
Publication number	US-2016355976-A1
Application number	US-201514730828-A
Country	US
Kind code	A1
Filing date	Jun 4, 2015
Priority date	Jun 4, 2015
Publication date	Dec 8, 2016
Grant date	—

Abstract

A fiber tow and methods for separating a fiber tow are disclosed. The fiber tow may include adjacent filaments and a polymer coating covering at least a portion of the adjacent filaments. The polymer coating may include a polymer that is configured to contract in a direction generally parallel to the adjacent filaments and expand in a direction generally perpendicular to the adjacent filaments. The polymer coating may contract/expand in response to an energy source, such as heat or a UV light source. The methods may include coating at least a portion of a plurality of filaments with a polymer, bundling the filaments into a fiber tow, and exposing the fiber tow to an energy source to contract the polymer in a direction generally parallel to the filaments and to expand the polymer in a direction generally perpendicular to the filaments. The filaments may be carbon fiber filaments.

First claim

What is claimed is:

1 . A fiber tow comprising:
adjacent filaments; and a polymer coating covering at least a portion of the adjacent filaments, the polymer coating including a polymer that is configured to, independent of the adjacent filaments, contract in a direction generally parallel to the adjacent filaments and expand in a direction generally perpendicular to the adjacent filaments.

2 . The fiber tow of claim 1 , wherein the polymer is configured to contract in a direction parallel to the adjacent filaments and expand in a direction perpendicular to the adjacent filaments when exposed to a heat source.

3 . The fiber tow of claim 1 , wherein the polymer is configured to contract in a direction parallel to the adjacent filaments and expand in a direction perpendicular to the adjacent filaments when exposed to a UV light source.

4 . The fiber tow of claim 1 , wherein the filaments are carbon fiber filaments.

5 . The fiber tow of claim 1 , wherein the fiber tow is a fiber tow segment having a length of 1 to 100 mm.

6 . The fiber tow of claim 1 , wherein the polymer includes a blend of polystyrenes, high impact polystyrenes, and elastomers.

7 . The fiber tow of claim 1 , wherein the polymer is configured to expand at least 25% in the direction generally perpendicular to the adjacent filaments such that a diameter of the fiber tow expands at least 25% when the polymer is exposed to an energy source.

8 . The fiber tow of claim 1 , wherein the polymer is configured to expand in the direction generally perpendicular to the adjacent filaments such that gaps are formed between the adjacent filaments when the polymer is exposed to an energy source.

9 . The fiber tow of claim 1 , wherein the polymer directly contacts the portion of the adjacent filaments.

10 . A method of separating filaments in a fiber tow, comprising:
coating at least a portion of a plurality of filaments with a polymer; bundling the filaments into a fiber tow; and exposing the fiber tow to an energy source to contract the polymer in a direction generally parallel to the filaments and to expand the polymer in a direction generally perpendicular to the filaments.

11 . The method of claim 10 , wherein the plurality of filaments are carbon fiber filaments.

12 . The method of claim 10 , wherein the energy source is a heat source.

13 . The method of claim 12 , wherein the heat source heats the fiber tow to a temperature of 50° C. to 250° C.

14 . The method of claim 10 , wherein the energy source is a UV light source.

15 . The method of claim 10 further comprising cutting the fiber tow into a plurality of fiber tow segments and the exposing step includes exposing the fiber tow segments to the energy source.

16 . The method of claim 10 further comprising cutting the fiber tow into a plurality of fiber tow segments; and
dropping the fiber tow segments onto a receiving surface;
the exposing step including exposing the fiber tow segments to the energy source during at least a portion of the dropping step.

17 . The method of claim 16 , wherein the receiving surface is a carrier film having a resin applied thereon.

18 . The method of claim 17 further comprising forming a sheet molding compound including the fiber tow segments.

19 . A sheet molding compound comprising:
first and second spaced apart carrier films; a plurality of fiber tow segments disposed between the first and second carrier films, each segment including a plurality of spaced apart filaments connected by a plurality of spaced apart polymer portions; and resin disposed between the first and second carrier films and within gaps formed between the polymer portions.

20 . The sheet molding compound of claim 19 , wherein the plurality of spaced apart filament are carbon fiber filaments.

Assignees

• Ford Global Tech Llc

Inventors

• Zhao Haibo

Classifications

• B29K2025/06

  PS, i.e. polystyrene · CPC title

• B29C70/50 Primary

  for producing articles of indefinite length, e.g. prepregs, sheet moulding compounds [SMC] or cross moulding compounds [XMC] · CPC title

• D07B7/145 Primary

  Coating or filling-up interstices · CPC title

• D06M15/233 Primary

  aromatic, e.g. styrene · CPC title

• D07B2201/2012

  comprising polymers · CPC title