Aligned discontinuous fiber preforms, composites and systems and processes of manufacture

Patent metadata

Field	Value
Publication number	US-11047078-B2
Application number	US-202016843362-A
Country	US
Kind code	B2
Filing date	Apr 8, 2020
Priority date	Aug 8, 2017
Publication date	Jun 29, 2021
Grant date	Jun 29, 2021

Abstract

A process for aligning discontinuous fibers, and composite products and mats comprised of highly aligned discontinuous fibers, including products of the process. Aligned discontinuous fiber composite products include a matrix of fibers, each fiber having a longitudinal fiber axis, the composite comprising a free, uncut edge extending along an edge axis. The longitudinal fiber axis of a majority of the fibers in the composite product are aligned within a predetermined alignment tolerance of an alignment axis non-parallel to the edge axis. Aligned discontinuous fiber mats may have a first areal density of fibers in a first region of the composite located inward relative to the free, uncut edge, and a second area density at or adjacent to the free, uncut edge.

First claim

What is claimed:

1. A process for aligning discontinuous fibers to form an aligned discontinuous fiber composite product, the process comprising:
distributing a first fluid mixture including a first plurality of discontinuous fibers dispersed in a first carrier fluid onto a first free surface to cause the fluid mixture to traverse the first free surface in a film with the assistance of gravity toward a porous belt positioned beneath the first free surface, wherein an entirety of the first free surface is positioned at an elevation above an entirety of the porous belt;
moving the porous belt in a travel direction; and
depositing the fluid mixture onto the porous belt from the first free surface and causing the discontinuous fibers to align together along a first impingement axis to form a first layer of aligned discontinuous fibers and causing the first carrier fluid to separate from the discontinuous fibers and pass through the porous belt.

2. The process of claim 1 , further comprising positioning a first substrate material on top of the porous belt and forming the first layer of aligned discontinuous fibers on top of the first substrate material.

3. The process of claim 1 , wherein the first fluid mixture further comprises a plurality of first particles dispersed in the first carrier fluid along with the first plurality of discontinuous fibers.

4. The process of claim 1 , wherein the first layer of aligned discontinuous fibers has a first areal density in a first region located inward relative to the edges, and an areal density in edge regions adjacent each edge different than the first areal density, the process further comprising removing the edge regions and recycling the discontinuous fibers in the removed edge regions back into the first fluid mixture.

5. The process of claim 1 , further comprising distributing a second fluid mixture including a second plurality of discontinuous fibers dispersed in a second carrier fluid onto a second free surface positioned after the first free surface relative to the travel direction of the porous belt so that the second plurality of discontinuous fibers lands on the first layer of aligned discontinuous fibers and along a second impingement axis thereby forming a second layer of aligned discontinuous fibers disposed above the first layer of aligned discontinuous fibers.

6. The process of claim 5 , wherein the first impingement axis is oriented at an oblique angle with respect to the second impingement axis.

7. The process of claim 5 , wherein one of:
the second plurality of discontinuous fibers comprises a different type of discontinuous fibers than the first plurality of discontinuous fibers;
the second plurality of discontinuous fibers comprises a different blend of discontinuous fibers than the first plurality of discontinuous fibers;
the second carrier fluid comprises a different carrier fluid than the first carrier fluid;
the second free surface has a second angle relative to a belt travel axis that is different than a first angle of the first free surface relative to the belt travel axis; or
a combination thereof.

8. The process of claim 5 , wherein the first fluid mixture further comprises one or more first particles dispersed in the first carrier fluid along with the first plurality of discontinuous fibers, and the second fluid mixture further comprises a plurality of second particles dispersed in the second carrier fluid along with the second plurality of discontinuous fibers, wherein the second particles comprise a different material than the first particles.

9. The process of claim 5 , further comprising positioning a first substrate material on top of the porous belt and forming the first layer of aligned discontinuous fibers on top of the first substrate material and introducing a second substrate material above the first layer of aligned discontinuous fibers after the first free surface and before of the second free surface relative to the travel direction of the porous belt, and disposing the second layer of aligned discontinuous fibers on the second substrate material.

10. An aligned discontinuous fiber composite product comprising at least one layer of aligned discontinuous fibers made by the process of:
distributing a first fluid mixture including a first plurality of discontinuous fibers dispersed in a first carrier fluid onto a first free surface to cause the fluid mixture to traverse the first free surface in a film with the assistance of gravity toward a porous belt positioned beneath the first free surface, wherein an entirety of the first free surface is positioned at an elevation above an entirety of the porous belt;
moving the porous belt in a travel direction; and
depositing the fluid mixture onto the porous belt from the first free surface and causing the discontinuous fibers to align together along a first impingement axis to form a first layer of aligned discontinuous fibers and causing the first carrier fluid to separate from the discontinuous fibers and pass through the porous belt.

11. The aligned discontinuous fiber composite product of claim 10 , wherein each fiber has a longitudinal fiber axis, the composite product comprising a free, uncut edge extending along an edge axis, wherein the longitudinal fiber axis of a majority of the discontinuous fibers in the composite product are aligned within a predetermined alignment tolerance of an alignment axis non-parallel to the edge axis.

12. The aligned discontinuous fiber composite product of claim 11 , further comprising a substrate material on which the first layer of aligned discontinuous fibers are disposed.

13. The aligned discontinuous fiber composite product of claim 12 , wherein the first layer of aligned discontinuous fibers on top of the first substrate material has a pair of opposite edges parallel to the travel direction and non-parallel to the first impingement axis, each aligned fiber having a longitudinal fiber axis, the longitudinal fiber axis of a majority of the aligned discontinuous fibers in the composite product aligned within a predetermined alignment tolerance to the first impingement axis.

14. The aligned discontinuous fiber composite product of claim 10 , wherein the composite product comprises an aligned discontinuous fiber mat disposed on a substrate.

15. The aligned discontinuous fiber composite product of claim 14 having a first areal density of discontinuous fibers in a first region of the composite product located inward relative to the free, uncut edge, and a second area density at or adjacent to the free, uncut edge.

16. The aligned discontinuous fiber composite product of claim 15 , further comprising a band located between the first region and the uncut edge in which the areal density in the band comprises a gradient from the first areal density to the second areal density.

17. The aligned discontinuous fiber composite product of claim 14 , comprising a continuous mat having a first region with discontinuous fibers aligned along a first alignment axis and a second region with discontinuous fibers aligned along a second alignment axis.

18. An aligned discontinuous fiber composite product comprising a matrix of discontinuous fibers, each discontinuous fiber having a longitudinal fiber axis, the composite product comprising a free, uncut edge extending along an edge axis, wherein the longitudinal fiber axis of a majority of the discontinuous fibers in the composite product are aligned within a predetermined alignment tolerance of an alignment axis non-parallel to the edge axis, wherein the predetermined alig

Assignees

• Tierney John
• Vanarelli Alex
• Heider Dirk
• Yarlagadda Shridhar
• Gillespie Jr John W
• Univ Delaware

Inventors

• Tierney John
• Vanarelli Alex
• Heider Dirk
• Yarlagadda Shridhar
• Gillespie Jr John W

Classifications

• C08J5/247

  using fibres of at least two types · CPC title

• C08J5/243

  using carbon fibres · CPC title

• C08J2363/00

  Characterised by the use of epoxy resins; Derivatives of epoxy resins · CPC title

• C08J2381/06

  Polysulfones; Polyethersulfones · CPC title

• D04H1/732

  by fluid current, e.g. air-lay · CPC title