Method for forming reinforced pultruded profiles

Patent metadata

Field	Value
Publication number	US-9409347-B2
Application number	US-201113697404-A
Country	US
Kind code	B2
Filing date	Jun 22, 2011
Priority date	Jun 22, 2010
Publication date	Aug 9, 2016
Grant date	Aug 9, 2016

Abstract

A method and apparatus for forming a profile that contains at least one layer of continuous fibers and at least one layer of discontinuous fibers. Said method allowing the selective control of features to achieve a profile that has increased transverse strength and flexural modulus. The layer of continuous fibers may be formed from one or more continuous fiber reinforced ribbons (“CFRT”) ( 12 ) that contain fibers embedded within a thermoplastic polymer matrix, whereby a void fraction and in turn is minimized and flexural modulus is optimized Further, the ribbon (s) are consolidated so that the continuous fibers remain fixed in alignment in a substantially longitudinal direction (e.g., the direction of pultrusion). In addition to enhancing the tensile properties of the profile, the use of such ribbons also allows an improved handability when placing them into the desired position within the pultrusion die. The discontinuous fibers are also embedded within a thermoplastic matrix, in such a way as to assist in bonding of the layers to achieve the desired strength. At least a portion of the fibers are oriented in the transverse direction to provide increased transverse strength.

First claim

What is claimed is:

1. A method for forming a pultruded profile having a cross-sectional shape, the method comprising:
pulling a continuous fiber ribbon through a pultrusion die in a longitudinal direction, wherein the continuous fiber ribbon contains continuous fibers that are substantially oriented in the longitudinal direction and embedded within a first thermoplastic polymer matrix;
introducing a discontinuous fiber material into the pultrusion die, wherein the discontinuous fiber material contains discontinuous fibers embedded within a second thermoplastic matrix, and wherein the discontinuous fiber material is introduced into the pultrusion die by providing the discontinuous fiber material at an input angle relative to the longitudinal direction, wherein the input angle is about 45° or more, and flowing the provided discontinuous fiber material through a curved inlet from the input angle to the longitudinal direction such that the discontinuous fiber material flows in the longitudinal direction before combining the discontinuous fiber material and the continuous fiber ribbon; and
within the pultrusion die, combining the discontinuous fiber material and the continuous fiber ribbon to form first and second layers of the profile, wherein the first layer is positioned adjacent to the second layer and includes the discontinuous fiber material, and wherein the second layer includes the continuous fiber ribbon.

2. The method of claim 1 wherein the continuous fibers, the discontinuous fibers, or both, include glass fibers, carbon fibers, or a combination of glass and carbon fibers.

3. The method of claim 1 , wherein the first thermoplastic polymer matrix, the second thermoplastic polymer matrix, or both, include a polyoiefin, polyether ketone, polyetherimide, polyarylene ketone, liquid crystal polymer, polyarylene sulfide, fluoropolymer, polyacetal, polyurethane, polycarbonate, styrenic polymer, polyester, polyimide, or a combination thereof.

4. The method of claim 1 , wherein the first thermoplastic matrix includes a first thermoplastic polymer and the second thermoplastic matrix includes a second thermoplastic polymer, wherein the first and second thermoplastic polymers are the same.

5. The method of claim 1 , wherein the continuous fiber ribbon has a void fraction of about 2% or less.

6. The method of claim 1 , wherein the continuous fiber ribbon is formed by a method that comprises:
passing the continuous fibers through an extrusion device that defines a tortuous pathway for impregnating the fibers with the first thermoplastic polymer matrix; and
thereafter, consolidating the impregnated fibers into the ribbon.

7. The method of claim 6 , wherein a manifold assembly supplies the thermoplastic matrix to the extrusion device, the manifold assembly comprising branched runners through which the thermoplastic matrix flows.

8. The method of claim 6 , wherein the continuous fibers are under tension when impregnated with the thermoplastic matrix.

9. The method of claim 1 , wherein the thermoplastic polymer matrix constitutes from about 10 wt.% to about 60 wt.% of the ribbon and the continuous fibers constitutes from about 40 wt.% to about 90 wt% of the ribbon.

10. The method of claim 1 , wherein the discontinuous fibers include long fibers.

11. The method of claim 1 , further comprising pulling the continuous fiber ribbon through a consolidation die that is positioned upstream from the pultrusion die.

12. The method of claim 1 , wherein at least a portion of the discontinuous fibers are oriented at an angle relative to the longitudinal direction.

13. The method of claim 1 , wherein the input angle is from about 75° to about 90°.

14. The method of claim 1 wherein a first mandrel section is positioned within an interior of the pultrusion die, the discontinuous fiber material flowing over the first mandrel section to assume a shape that is defined between an external surface of the first mandrel section and an interior surface of the pultrusion die.

15. The method of claim 14 , wherein a second mandrel section is also positioned within the interior of the pultrusion die, the continuous fiber ribbon flowing over the second mandrel section to assume a shape that is defined between an external surface of the second mandrel section and an interior surface of the pultrusion die.

16. The method of claim 1 , wherein multiple layers of continuous fiber ribbon are pulled through the pultrusion die and brought together to form the second layer of the profile.

17. The method of claim 1 , further comprising applying a capping layer to the first layer, the second layer, or both.

18. The method of claim 1 , further comprising cooling the shaped profile to solidify the first and second layers into position.

19. The method of claim 1 , wherein the ratio of the weight of the second layer to the weight of the first layer is from about 0.2 to about 10.

20. The method of claim 1 , Wherein the second layer has a thickness of from about 0.5 to about 3.0 millimeters and the thickness of the first layer is from about 0.5 to about 1.5 millimeters.

21. The method of claim 1 , wherein the profile is hollow.

22. The method of claim 21 wherein the hollow profile has a generally rectangular shape.

23. The method of claim 21 , wherein the first layer forms an inner layer of the hollow profile.

24. The method of claim 23 , wherein the second layer extends substantially around the periphery of the first layer.

25. The method of claim 23 , wherein the second layer is located in one or more discrete regions adjacent to the first layer.

26. The method of claim 21 , wherein the second layer forms an inner layer of the hollow profile.

27. The method of claim 26 , wherein the first layer extends substantially around the periphery of the second layer.

28. The method of claim 26 , wherein the first layer is located in one or more discrete regions adjacent to the second layer.

29. The method of claim 1 , wherein the profile is solid.

30. The method of claim 29 , wherein the solid profile is U- or C-shaped.

31. The method of claim 1 , wherein the cross-section shape of the profile is substantially the same along the entire length of the profile.

Assignees

• Nelson Sherri M
• Eastep David W
• Regan Timothy A
• Ticona Llc

Inventors

• Nelson Sherri M
• Eastep David W
• Regan Timothy A

Classifications

• B29C70/52 Primary

  Pultrusion, i.e. forming and compressing by continuously pulling through a die · CPC title

• B29C70/521

  and impregnating the reinforcement before the die · CPC title

• B29B15/122

  with a matrix in liquid form, e.g. as melt, solution or latex · CPC title

• B29C70/081 Primary

  Combinations of fibres of continuous or substantial length and short fibres · CPC title

• Y10T428/249921

  Web or sheet containing structurally defined element or component · CPC title