Discontinuous-fiber composites and methods of making the same

Patent metadata

Field	Value
Publication number	US-10920041-B2
Application number	US-201615307196-A
Country	US
Kind code	B2
Filing date	Aug 11, 2016
Priority date	Aug 11, 2015
Publication date	Feb 16, 2021
Grant date	Feb 16, 2021

Abstract

The invention relates to compositions comprising composite materials comprised of discontinuous fibers and one or more polymers and/or oligomers. The invention relates to methods of making the same. The composite materials can be in the form of compositions, composite sheets, laminates, pellets, and/or shaped composite products.

First claim

What is claimed is:

1. A method for preparing a polymer composite composition comprising:
mixing discontinuous fibers and one or more polymers and/or oligomers to form a mixture in an extruder; wherein the discontinuous fibers have a minimum length of about 0.16 inches when added to the extruder; wherein said polymer and/or oligomer is a thermoplastic or a thermoset; and wherein said discontinuous fibers are aramid fibers, carbon fibers, ceramic fibers, glass fibers, polymeric fibers, or mineral-based fibers, or a combination thereof
rolling the mixture to form the polymer composite composition into a sheet, wherein the rolling orients the discontinuous fibers in one direction; and
wherein one or more stages of the method minimize the fiber length attrition.

2. The method of claim 1 , wherein said extruder is a single-screw or twin-screw extruder.

3. The method of claim 1 , wherein the method further comprises drawing the sheet after the rolling step, and wherein the drawing further orients the discontinuous fibers in the same direction.

4. The method of claim 1 , wherein the discontinuous fiber is present in the composite sheet at a load of between about 2 wt. % and about 75 wt. %; and wherein the polymer and/or oligomer can be present in the composite at a load of between about 25 wt. % and about 98 wt. %.

5. The method of claim 1 , wherein the extruder feeds into a rolling process through a die that is larger than the extruder opening, through a die that is the same size as the extruder opening, or without passing the extrudate through a die.

6. The method of claim 1 , further comprising laminating the sheet to form a laminate.

7. The method of claim 6 , wherein the laminate further comprises a composite sheet prepared by a different method, a polymer sheet, a metal sheet, or combinations thereof.

8. The method of claim 1 wherein the said mixing occurs during partial or complete in-situ polymerization of a monomer and/or oligomer.

9. The method of claim 1 , wherein the rolling step is performed between two or more rollers.

10. The method of claim 1 , wherein the rolling step is performed between multiple sets of rollers.

11. The method of claim 1 wherein the combining step further comprising combining additional ingredients; and wherein the mixing step further comprising mixing additional ingredients.

12. The method of claim 1 further comprising chipping the composite sheet to form pellets.

13. The method of claim 1 further comprising forming a shaped composite product.

14. The method of claim 13 , wherein the forming step is compression molding, pressure forming, thermoforming, or injection molding.

Assignees

• South Dakota Board Of Regents

Inventors

• Brady Andrew T
• Mannhalter Bert D
• Salem David R

Classifications

• B32B7/02

  Physical, chemical or physicochemical properties · CPC title

• B29C48/475

  using pistons, accumulators or press rams · CPC title

• B29C48/0022

  combined with cutting · CPC title

• B32B2260/023

  Two or more layers · CPC title

• B32B2262/106

  Carbon fibres, e.g. graphite fibres · CPC title