Method of splitting fiber tows

Patent metadata

Field	Value
Publication number	US-10099435-B2
Application number	US-201514730828-A
Country	US
Kind code	B2
Filing date	Jun 4, 2015
Priority date	Jun 4, 2015
Publication date	Oct 16, 2018
Grant date	Oct 16, 2018

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 method of separating filaments coated with a polymer in a fiber tow, comprising:
cutting the fiber tow into segments;
dropping the segments such that the segments fall in a vertical direction; and
as the segments fall, exposing the segments to first energy sources aligned in a first plane orthogonal to the vertical direction and second energy sources aligned in a second plane vertically spaced from and parallel to the first plane.

2. The method of claim 1 , wherein the filaments are carbon fiber filaments.

3. The method of claim 1 , wherein the first and second energy sources are heat sources selected from the group consisting of a flame heater and a furnace.

4. The method of claim 3 , wherein the heat sources heat the segments to a temperature of 50° C. to 250° C.

5. The method of claim 1 , wherein the energy source is adapted to emit energy selected from the group consisting of X-rays, gamma rays, microwaves, and radio waves.

6. The method of claim 1 further comprising dropping the fiber tow segments onto a receiving surface that is a moving receiving surface.

7. The method of claim 6 , wherein the receiving surface is a first carrier film having a resin applied thereon, and wherein the method further comprises:
applying a second carrier film having a resin applied thereon to the segments.

8. The method of claim 7 further comprising:
forming a sheet molding compound including the segments; and
compacting the SMC material including the segments with a roller.

9. The method of claim 1 , wherein during the dropping, the segments receive energy intermittently as they fall from the first energy sources to the second energy sources.

10. The method of claim 1 , wherein during the dropping, the segments receive energy continuously as they fall from the first energy sources to the second energy sources.

11. The method of claim 1 , wherein during the dropping, the polymer splits into spaced apart, discontinuous portions.

12. The method of claim 11 , wherein the spaced apart, discontinuous portions and adjacent filaments define gaps within the segment.

13. The method of claim 1 , wherein during the dropping, the polymer expands at least 25% in the direction generally perpendicular to the adjacent filaments such that a diameter of a segment expands at least 25% when the polymer is exposed to the energy source.

14. The method of claim 1 , wherein during the dropping, a filament is detached from an adjacent filament.

15. A method comprising:
cutting and dropping polymer-coated segments from a tow;
as the segments fall, intermittently exposing the segments to heaters such that a segment
is exposed to a first plurality of heaters at a first fall location,
is not exposed to a heater at a second fall location vertically below the first fall location, and
is exposed to a second plurality of heaters at a third fall location vertically below the second fall location.

16. A method of separating polymer-coated filaments of a fiber tow, comprising:
passing the fiber tow through a roller-integrated cutter such that
the fiber tow is cut into segments, and
the segments fall vertically from the roller-integrated cutter;

as the segments fall, exposing the segments to a first plurality of at least four energy sources that define a square about the vertically-falling segments and a second plurality of energy sources vertically offset from the first plurality.

Assignees

• Ford Global Tech Llc

Inventors

• Zhao Haibo

Classifications

• B29L2007/008

  Wide strips, e.g. films, webs · CPC title

• D07B2801/10

  Smallest filamentary entity of a rope or strand, i.e. wire, filament, fiber or yarn · CPC title

• B29K2025/06

  PS, i.e. polystyrene · CPC title

• D07B2201/2012

  comprising polymers · CPC title

• D07B2205/2089

  showing heat contraction · CPC title