System for producing chopped roving thermoplastic composite sheets

Patent metadata

Field	Value
Publication number	US-12070933-B2
Application number	US-202117533333-A
Country	US
Kind code	B2
Filing date	Nov 23, 2021
Priority date	Jul 2, 2019
Publication date	Aug 27, 2024
Grant date	Aug 27, 2024

Abstract

A chopped roving thermoplastic composite sheet includes a web or mesh of chopped rovings and a thermoplastic resin that fully saturates the web or mesh of chopped rovings. The web or mesh of chopped rovings is not mechanically bonded and does not include a binder that bonds or adheres the chopped rovings together other than thermoplastic resin. As such, the thermoplastic resin and the web or mesh of chopped rovings are able to flow and conform to a mold or cavity when the chopped roving thermoplastic composite sheet is pressed within the mold or cavity and when the chopped roving thermoplastic composite sheet is heated to above the melting temperature of the thermoplastic resin.

First claim

What is claimed is:

1. A system for manufacturing a chopped roving thermoplastic composite sheet, the system comprising:
a double belt mechanism that includes an upper belt and a lower belt, the upper belt being positioned atop the lower belt to compress a chopped roving web or mesh that is passed through the double belt mechanism and the lower belt having a longitudinal length that is substantially longer than the upper belt;
a fiber applicator positioned above the lower belt so that the fiber applicator disperses chopped rovings directly onto the lower belt as the lower belt is moved under and past the fiber applicator, the chopped rovings being dispersed onto the lower belt prior to application of any thermoplastic resin to form the chopped roving web or mesh;
a resin applicator that is positioned atop the lower belt, the resin applicator being configured to apply a thermoplastic resin to the chopped roving web or mesh; and
an oven that is configured to melt the thermoplastic resin as the chopped roving web or mesh and the thermoplastic resin are moved through the oven; wherein:
the double belt mechanism compresses the chopped roving web or mesh and the melted thermoplastic resin as the chopped roving web or mesh is passed through the oven such that the melted thermoplastic resin is dispersed within the chopped roving web or mesh and saturates the chopped roving web or mesh;
the system does not include an entangling device that entangles the chopped rovings of the chopped roving web or mesh and does not include a binder application device that applies a binder to the chopped rovings such that the chopped roving web or mesh is not mechanically bonded and does not include a binder other than the thermoplastic resin; and
the chopped roving thermoplastic composite sheet is substantially free of unpolymerized resin materials;

wherein the chopped roving web or mesh includes glass fibers, carbon fibers, basalt fibers, metal fibers, ceramic fiber, cellulosic fibers, natural fibers, aramid fibers, inorganic fibers, polymer fibers, or a combination thereof.

2. The system of claim 1 , further comprising a cooling mechanism that is configured to cool the chopped roving web or mesh after the chopped roving web or mesh and the melted thermoplastic resin are pressed by the double belt press mechanism.

3. The system of claim 1 , wherein the fiber applicator and the resin applicator are positioned immediately adjacent one another so that the chopped rovings and the thermoplastic resin are simultaneously dispersed atop the lower belt such that the thermoplastic resin is dispersed throughout the chopped roving web or mesh.

4. The system of claim 1 , wherein the fiber applicator is a fiber chopper that is positioned above the lower belt, the fiber chopper being configured to cut rovings to form the chopped rovings of the chopped roving web or mesh, the fiber chopper being positioned so that as the rovings are cut, the chopped rovings fall atop the lower belt and form the chopped roving web or mesh.

5. The system of claim 4 , wherein the chopped rovings comprise multiple roving types or roving sizes, and wherein the chopped rovings fall atop the lower belt so that the multiple roving types or roving sizes are uniformly dispersed or mixed to form a hybrid chopped roving web or mesh.

6. The system of claim 5 , wherein:
the multiple roving types or roving sizes includes polymer fibers that are configured to melt within the oven and also includes reinforcing rovings;
the fiber chopper cuts both the polymer fibers and the reinforcing rovings so that the polymer fibers and the reinforcing rovings fall atop the lower belt and form the chopped roving web or mesh; and
the fiber chopper functions as both the fiber applicator and the resin applicator in which the polymer fibers are the thermoplastic resin that is applied to the chopped roving web or mesh.

7. The system of claim 4 , wherein the fiber chopper is a first fiber chopper and the chopped rovings are first chopped rovings, and wherein the system further comprises a second fiber chopper positioned above the lower belt, the second fiber chopper being configured to cut second rovings to form second chopped rovings, the second fiber chopper being positioned so that as the second rovings are cut, the second chopped rovings fall atop the first chopped rovings and form a layered or hybrid chopped roving web or mesh.

8. The system of claim 7 , wherein the second rovings include polymer fibers that are configured to melt within the oven and that are configured to be dispersed within the first chopped rovings to fully saturate the first chopped rovings.

9. The system of claim 4 , further comprising a roller around which a fabric or nonwoven mat roll is positioned, wherein the system is configured to unwind the fabric or nonwoven mat from the roller form a layered or hybrid chopped roving web or mesh comprising the chopped rovings and the fabric or nonwoven mat, wherein the layered or hybrid chopped roving web or mesh is subjected to the resin applicator, the double belt mechanism, and the oven such that the thermoplastic resin is dispersed within and fully saturates the layered or hybrid chopped roving web or mesh.

10. The system of claim 1 , wherein the fiber applicator is a fiber scattering device that is positioned above the lower belt, the fiber scattering device being configured to scatter pre-cut chopped rovings atop the lower belt to form the chopped roving web or mesh.

11. The system of claim 10 , wherein:
the fiber scattering device is configured to scatter chopped rovings of multiple roving types or roving sizes including polymer fibers that are configured to melt within the oven and also including reinforcing rovings;
the polymer fibers and the reinforcing rovings fall atop the lower belt to form the chopped roving web or mesh; and
the fiber scattering device functions as both the fiber applicator and the resin applicator in which the polymer fibers are the thermoplastic resin that is applied to the chopped roving web or mesh.

12. The system of claim 1 , wherein the resin applicator is a powder application device that is configured to disperse powder thermoplastic resin onto the chopped roving web or mesh as the chopped roving web or mesh is moved past the powder application device such that the powder thermoplastic resin falls into interstices between the chopped rovings of the chopped roving web or mesh.

13. The system of claim 1 , wherein the resin applicator is an extruder device that is configured to extrude a molten thermoplastic resin sheet atop the chopped roving web or mesh.

14. The system of claim 1 , wherein the resin applicator is a fiber chopper or a fiber scattering device that is configured to disperse thermoplastic resin fibers atop or within the chopped roving web or mesh.

15. The system of claim 1 , wherein fibers in the chopped rovings are treated with a sizing composition having a coupling agent that promotes bonding between the chopped rovings and the thermoplastic resin.

16. The system of claim 1 , further comprising a cutting mechanism that cuts the chopped roving thermoplastic composite sheet to a desired length and width, the cutting mechanism being positioned after the oven.

17. The system of claim 1 , wherein the thermoplastic resin comprises polyolefins, polypropylene (PP), high-density polyethylene (HDPE), polyamides, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycarbonate (PC), polyphthalamide (PPA), acrylonitrile-butadiene-styrene (ABS), PC/ABS, thermoplastic polyurethane (TPU), polyphe

Assignees

• Johns Manville

Inventors

• Zhang Mingfu
• Asrar Jawed

Classifications

• B29C70/508

  and first forming a mat composed of short fibres · CPC title

• B29C70/12

  using fibres of short length, e.g. in the form of a mat {(non-woven fabrics per se D04H1/00)} · CPC title

• B29C70/506

  and impregnating by melting a solid material, e.g. sheet, powder, fibres (B29C70/508 takes precedence) · CPC title

• B32B2262/101

  Glass fibres · CPC title

• B32B2260/046

  Synthetic resin · CPC title