Method for recycling polymeric film

• US 5,268,074 A
• Filed: 03/21/1991
• Issued: 12/07/1993
• Est. Priority Date: 03/27/1990
• Status: Expired due to Term

• Current Assignee: Allstate Insurance Company (Allstate Corporation), Bank of Oklahoma NA (BOK Financial Corporation)
• Original Assignee: Advanced Environmental Recycling Technologies, Inc. (CRH PLC)
• Inventors: Brooks, Joe G., Brooks, J. Douglas, Goforth, Billy D., Goforth, Charles L.
• Primary Examiner(s): Jones, W. Gary
• Assistant Examiner(s): BURNS, TODD
• Application Number:
  US07/672,832
• Time in Patent Office: 992 Days
• Field of Search: 209/3, 209/10, 209/173, 241/20, 241/24, 162/4, 162/5, 162/191
• US Class Current: 162/4
• CPC Class Codes: B03B 1/04 by additives
• CPC Class Codes: B03B 5/28 by sink-float separation
• CPC Class Codes: B03B 9/061 the refuse being industrial
• CPC Class Codes: B29B 17/02 Separating plastics from other materials
• CPC Class Codes: B29B 2017/0244 in liquids
• CPC Class Codes: B29B 2017/0289 Washing the materials in liquids
• CPC Class Codes: B29B 2017/0484 Grinding tools, roller mills or disc mills
• CPC Class Codes: B29K 2023/06 PE, i.e. polyethylene
• CPC Class Codes: B29K 2105/065 containing impurities
• CPC Class Codes: B29K 2705/00 Use of metals, their alloys or their compounds, for preformed parts, e.g. for inserts
• CPC Class Codes: B29K 2711/12 Paper, e.g. cardboard
• CPC Class Codes: B29K 2711/14 Wood, e.g. woodboard or fibreboard
• CPC Class Codes: B29L 2007/008 Wide strips, e.g. films, webs
• CPC Class Codes: D21B 1/026 Separating fibrous materials from waste
• CPC Class Codes: D21B 1/322 coated with synthetic materials
• CPC Class Codes: Y02W 30/52 Mechanical processing of waste for the recovery of materials, e.g. crushing, shredding, separation or disassembly
• CPC Class Codes: Y02W 30/62 Plastics recycling; Rubber recycling
• CPC Class Codes: Y02W 30/64 Paper recycling

Abstract

A method for producing rolled plastic pellets comprising from about 5 to about 10 weight percent cellulosic fiber and less than about 10 weight percent water from mixed plastic waste comprising polymeric film.

Claims

1. A method for reclaiming polymeric film from mixed plastic waste comprising polymeric film and cellulosic fiber, said method comprising the steps of:

Introducing the plastic waste into apparatus adapted to reduce the polymeric film to pieces having a maximum dimension ranging between about 1 inch and about 4 inches;

Separating the polymeric film from a portion of the cellulosic fiber by passing the plastic waste through at least one wash tank;

Further reducing the size of the pieces of polymeric film to pieces having a maximum dimension of about 1/2 inch;

Separating the polymeric film and a further portion of the cellulosic fiber by flotation with agitation;

Dewatering the polymeric film;

Drying the polymeric film to a moisture content of less than about 10 weight percent; and

Rolling the polymeric film into pellets.

2. The method of claim 1 wherein the plastic waste comprises from about 6 percent to about 33 percent cellulosic fiber by weight.

3. The method of claim 1 wherein the plastic waste is baled.

4. The method of claim 3 wherein the baled plastic waste is cut into sections before reducing the pieces of polymeric film to a maximum dimension between about 1 and about 4 inches.

5. The method of claim 1 wherein the plastic waste is screened prior to washing.

6. The method of claim 1 wherein the step of reducing the polymeric film to pieces having a maximum dimension between about 1 and about 4 inches includes the step of reducing the plastic waste in a shredder.

7. The method of claim 1 wherein the step of reducing the polymeric film to a maximum dimension of about 1/2 inch includes the step of reducing the maximum dimension in a wet grinder.

8. The method of claim 1 wherein the step of dewatering the polymeric film comprises the step of passing it through a screw press for dewatering.

9. The method of claim 1 wherein the dewatered polymeric film is dried to a moisture content or less than about 10 weight percent.

10. The method of claim 1 comprising the additional step of passing the dried polymeric film through a cyclone separator to remove an additional portion of the cellulosic fiber therefrom.

11. The method of claim 1 wherein the pellets comprise from about 5 percent to about 10 percent cellulosic fiber by weight.

12. The method of claim 1 wherein the pellets comprise less than about 8 percent moisture by weight.

13. The method of claim 1 wherein the polymeric film is high density polyethylene.