Processes for recycling carpet and products of such processes

• US 8,864,057 B2
• Filed: 11/04/2011
• Issued: 10/21/2014
• Est. Priority Date: 11/04/2011
• Status: Active Grant

• Current Assignee: SHAW Industries Group Incorporated (Berkshire Hathaway Incorporated)
• Original Assignee: SHAW Industries Group Incorporated (Berkshire Hathaway Incorporated)
• Inventors: Bork, Joseph E., Paspek, Stephen C. Sr., Schroeder, Alan F., Heise, William H.
• Primary Examiner(s): Francis, Faye
• Application Number:
  US13/289,703
• Publication Number:
  US 20130112727A1
• Time in Patent Office: 1,082 Days
• Field of Search: 241/23, 241/24.19, 241/24.29, 241/DIG.38
• US Class Current: 241/23
• CPC Class Codes: B02C 19/186 Use of cold or heat for disintegrating B02C4/44, B02C7/17, B02C11/08 take precedence
• CPC Class Codes: B29B 17/02 Separating plastics from other materials
• CPC Class Codes: B29B 17/021 using local heating of the reinforcement
• CPC Class Codes: B29B 2017/0217 Mechanical separating techniques; devices therefor
• CPC Class Codes: B29B 2017/0255 using different melting or softening temperatures of the materials to be separated
• CPC Class Codes: B29K 2067/003 PET, i.e. poylethylene terephthalate
• CPC Class Codes: B29K 2077/00 Use of PA, i.e. polyamides, e.g. polyesteramides or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2105/06 containing reinforcements, fillers or inserts
• CPC Class Codes: B29K 2105/065 containing impurities
• CPC Class Codes: B29K 2105/26 Scrap or recycled material
• CPC Class Codes: B29K 2313/00 Use of textile products or fabrics as reinforcement B29K2105/06 takes precedence
• CPC Class Codes: B29L 2031/7322 Carpets
• CPC Class Codes: C08G 63/183 Terephthalic acids
• CPC Class Codes: C08G 69/02 Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
• CPC Class Codes: C08J 11/04 of polymers
• CPC Class Codes: C08J 11/08 using selective solvents for polymer components
• CPC Class Codes: D01B 9/00 Other mechanical treatment of natural fibrous or filamentary material to obtain fibres or filaments
• CPC Class Codes: D06N 7/0071 characterised by their backing, e.g. pre-coat, back coating, secondary backing, cushion backing
• CPC Class Codes: Y02P 20/582 Recycling of unreacted starting or intermediate materials
• CPC Class Codes: Y02W 30/62 Plastics recycling; Rubber recycling
• CPC Class Codes: Y10S 241/38 : Solid waste disposal
• CPC Class Codes: Y10T 225/12 : With preliminary weakening

Abstract

Methods for the recycling of carpet are disclosed that produce clean face fiber suitable for industrial use. The methods allow the recovery of face fiber material, for example a polyester or a polyamide, from carpets that includes a face fiber material and a backing material, and include the steps of heating the carpet to a temperature lower than the melting point of the face fiber material, but higher than the initial thermal decomposition temperature of the backing material, for a time and at a temperature sufficient to thermally decompose, pyrolyze, or oxidize at least a portion of the backing material, rendering the backing material friable, that is more friable than the untreated backing; and applying mechanical force to the carpet so as to liberate the friable backing material from the face fiber material.

Claims

1. A process for recovering face fiber material from a carpet that includes a face fiber material and a backing material, the process comprising:

a) heating the carpet to a temperature lower than the melting point of the face fiber material, but higher than the thermal decomposition temperature of the backing material, for a time and at a temperature sufficient to thermally decompose at least a portion of the backing material, rendering the backing material friable; and

b) applying mechanical force to the carpet so as to liberate the face fiber material from the friable backing material.

2. The process of claim 1, wherein the carpet is heated in step a) to a temperature from about 175°

C. to about 260°

C.

3. The process of claim 1, wherein the face fiber material comprises nylon 6, and wherein the carpet is heated in step a) to a temperature from 175°

C. to 215°

C.

4. The process of claim 1, wherein the face fiber material comprises Nylon 66, and wherein the carpet is heated in step a) to a temperature from 175°

C. to 245°

C.

5. The process of claim 1, wherein the face fiber material comprises polyethylene terephthalate, and wherein the carpet is heated in step a) to a temperature from 175°

C. to 260°

C.

6. The process of claim 1, wherein the carpet is heated in step a) for a time from about 0.1 minute to about 120 minutes.

7. The process of claim 1, wherein steps a) and b) are carried out in the same apparatus.

8. The process of claim 1, wherein steps a) and b) are carried out sequentially.

9. The process of claim 1, wherein steps a) and b) are carried out simultaneously.

10. The process of claim 1, wherein steps a) and b) are carried out in a continuous process.

11. The process of claim 1, wherein the carpet is cooled between steps a) and b) causing at least a portion of the backing material to spontaneously fracture.

12. The process of claim, 1 wherein the face fiber material comprises a polyester.

13. The process of claim 1, wherein the face fiber material comprises a polyamide.

14. The process of claim 1, wherein the backing material comprises a polyolefin.

15. The process of claim 1, wherein the backing material comprises a natural fiber.

16. Face fiber material recovered according to the process of claim 1.

17. An extruded article comprising the face fiber material of claim 16.

18. An injection-molded article comprising the face fiber material of claim 16.

19. The process of claim 1, further comprising chemically recycling the face fiber material.

20. The process of claim 1, further comprising separating any inorganic filler from the friable backing material.

21. The inorganic filler separated according to the process of claim 20.

22. A process for recovering face fiber material from a carpet that includes a face fiber material and a backing material of different chemical composition than the face fiber material, the process comprising:

a) heating the carpet to a temperature lower than the melting point of the face fiber material, but higher than the initial thermal decomposition temperature of the backing material, for a time and at a temperature sufficient to thermally decompose and/or oxidize at least a portion of the backing material, rendering the backing material more friable than the untreated backing;

b) applying mechanical force to the carpet so as to liberate the face fiber material from the friable backing material; and

c) removing any contaminants from the face fiber material through one or more mechanical means.

23. The friable backing material recovered according to the process of claim 22.