Long fiber thermoplastic formed with recycled and renewable content

Patent metadata

Field	Value
Publication number	US-9499688-B2
Application number	US-201314370570-A
Country	US
Kind code	B2
Filing date	Jan 7, 2013
Priority date	Jan 6, 2012
Publication date	Nov 22, 2016
Grant date	Nov 22, 2016

Abstract

A molding composition formulation is provided that includes polypropylene, glass fiber, and a polypropylene substitute including recycled sheet molding composition transfer film. The polypropylene substitute is present from 1 to 35 total weight percent also may include natural cellulosic fibers or powders. A process is provided by which the polypropylene substitute is mixed and homogenized and then mixed with polypropylene and additives, and thereafter glass fiber. A reduction in the amount of virgin polypropylene used is reduced compared to conventional thermoplastic glass fiber filled moldings.

First claim

The invention claimed is:

1. A molding composition comprising:
polypropylene;
glass fiber; and
a polypropylene substitute comprising recycled sheet molding composition transfer film, said recycled sheet molding composition transfer film present at a loading of between 1 and 35 weight percent of the molding composition, said recycled sheet molding composition polypropylene transfer film being a byproduct of sheet molding composition production used as a carrier and a styrene barrier for a sheet molding composition resin paste and residual sheet molding composition resin paste materials, said polypropylene substitute being shredded into a variety of shapes including strips with a length to width aspect ratio of 2-1000:1, or polygonal shapes having aspect ratios of between 1-2:1 between a longest linear dimension and a shortest linear dimension before being homogenized with said polypropylene and said glass fiber in an extruder.

2. The molding composition of claim 1 wherein said polypropylene substitute further comprises a natural cellulosic filler of at least one of a natural cellulosic fiber or a natural cellulosic powder combined with said recycled sheet molding composition transfer film.

3. The molding composition of claim 2 wherein said natural cellulosic powder is selected from the group consisting of coconut shell powder, walnut shell powder, and rice hull.

4. The molding composition of claim 2 wherein said at least one natural cellulosic fiber is selected from the group consisting of coconut fibers, bamboo fibers, sugar cane fibers, and banana skin fibers.

5. The molding composition of claim 1 wherein said composition is a compression moldable long fiber thermoplastic (LFTD).

6. The molding composition of claim 1 wherein the proportion of said polypropylene is 30 to 40 total weight percent of said molding composition and said polypropylene substitute is 25 to 30 total weight percent of said molding composition.

7. A process for producing a molding composition of claim 1 comprising:
mixing recycled sheet molding composition transfer film to form a polypropylene substitute composition; and
combining said polypropylene substitute composition with polypropylene, one or more additives, and glass fiber.

8. The process of claim 7 wherein said mixing is done with a twin-screw extruder.

9. The process of claim 7 wherein said polypropylene substitute composition further comprises a natural cellulosic filler of at least one of a natural cellulosic fiber or a natural cellulosic powder combined with said recycled sheet molding composition transfer film.

10. The process of claim 9 where said natural cellulosic filler is said natural cellulosic powder, said natural cellulosic powder is at least one of coconut shell powder, walnut shell powder, or rice hull.

11. The process of claim 7 wherein said natural cellulosic filler is said natural cellulosic fiber.

12. The process of claim 11 wherein said natural cellulosic fiber is at least one of coconut fibers, bamboo fibers, sugar cane fibers, or banana skin fibers.

13. The process of claim 7 further comprising subjecting said molding composition to long fiber thermoplastic (LFTD) compression molding.

Assignees

• Continental Structural Plastics Inc

Inventors

• Guha Probir Kumar
• Siwajek Michael J
• Neogi Swati

Classifications

• C08L2205/16

  Fibres; Fibrils · CPC title

• C08L2205/08

  containing additives to improve the compatibility between two polymers · CPC title

• B29B7/7485

  with consecutive mixers, e.g. with premixing some of the components · CPC title

• C08J5/045

  with vegetable or animal fibrous material · CPC title

• B29B7/46

  with more than one shaft · CPC title