Method for recycling floor coverings
The present invention concerns a method for recycling used floor covering. Post-consumer or post-industrial fibrous floor coverings are shredded to form a fibrous dispersion. The dispersion is maintained at a content of about 20-65% low-melt thermoplastic. The shredded fibrous dispersion is conveyed into a chute feeder which converts it into a batt that is heated, compressed, and cooled to form a durable backing particularly suitable for flooring applications. The batt comprises vertical layers or strata of fibers to provide additional cushion for the backing. Additionally, a portion of the shredded fibrous dispersion can also be diverted and used to form a face layer and/or adhesive layer for a reconstituted floor covering.
1. A process for forming a portion of a surface covering comprising the steps of:
(a) conveying a dispersion of low-melt thermoplastic components and high-melt thermoplastic components into a chute feeder, wherein the low-melt thermoplastic component has a melting temperature of at least about 20° C. below melting temperatures for the high-melt thermoplastic components;
(b) maintaining about 20% to about 65% of the dispersion as the low-melt thermoplastic components;
(c) forming a batt with the dispersion;
(d) applying heat from above or below the batt, wherein the heat temperature is below the melting temperatures for high-melting components;
(e) applying pressure to the batt to compact the batt to form a sheet; and
(f) cooling the sheet, wherein before the step (a) the dispersion is produced by shredding a fibrous floor covering, wherein between steps (c) and (d), the batt is again shredded and then conveyed into a second chute feeder to form a second batt.
2. The process of claim 1 , wherein the batt weighs about 10 oz/yd 2 to about 50 oz/yd 2 .
3. The process of claim 1 , wherein the sheet has a density in the range of about 0.05 to about 0.25 g/cm 3 .
4. The process of claim 1 further comprising a step of adding a fibrous face layer or a step of adding an adhesive layer.
5. The process of claim 1 , wherein the heat temperature is from about 150° C. to about 240° C.
6. The process of claim 1 further comprising the step of embossing the batt.
7. The process of claim 1 wherein in step (d) heat is applied from above and below the batt.
8. A process for forming a portion of a surface covering comprising the steps of:
(a) conveying a dispersion of low-melt thermoplastic components and high-melt thermoplastic components into a chute feeder, wherein the low-melt thermoplastic component has a melting temperature of at least about 20° C. below melting temperatures for the high-melt thermoplastic components;
(b) maintaining about 20% to about 65% of the dispersion as the low-melt thermoplastic components by the step of adding low-melt or high-melt thermoplastic material to the dispersion;
(c) forming a batt with the dispersion;
(d) applying heat from above or below the batt, wherein the heat temperature is below the melting temperatures for high-melt components;
(e) applying pressure to the batt to compact the batt to form a sheet; and
(f) cooling the sheet.
9. The process of claim 8 , wherein the batt weighs about 10 oz/yd 2 to about 50 oz/yd 2 .
10. The process of claim 8 , wherein the sheet has a density in the range of about 0.05 to about 0.25 g/cm 3 .
11. The process of claim 8 further comprising a step of adding a fibrous face layer or a step of adding an adhesive layer.
12. The process of claim 8 , wherein the heat temperature is from about 150° C. to about 240° C.
13. The process of claim 8 comprising the step of embossing the batt.
14. The process of claim 8 wherein in step (d) heat is applied from above and below the batt.
15. A process for forming a portion of a surface covering comprising the steps of:
(a) conveying a dispersion of low-melt thermoplastic components and high-melt thermoplastic components into a chute feeder, wherein the low-melt thermoplastic component has a melting temperature of at least about 20° C. below melting temperatures for the high-melt thermoplastic components;
(b) maintaining about 20% to about 65% of the dispersion as the low-melt thermoplastic components;
(c) forming a batt with the dispersion;
(d) applying heat from above or below the batt, wherein the heat temperature is below the melting temperatures for high-melt components;
(e) applying pressure to the batt to compact the batt to form a sheet; and
(f) cooling the sheet,
wherein the dispersion comprises relatively short fibers and thermoplastic binder particles, wherein before step (a) some of the relatively short fibers and thermoplastic binder particles are filtered out of the dispersion, and wherein after step (c) the filtered fibers and thermoplastic binder particles are deposited over the batt.
16. The process of claim 15 , wherein the batt weighs about 10 oz/yd 2 to about 50 oz/yd 2 .
17. The process of claim 15 , wherein the sheet has a density in the range of about 0.05 to about 0.25 g/cm 3 .
18. The process of claim 15 further comprising a step of adding a fibrous face layer or a step of adding an adhesive layer.
19. The process of claim 15 , wherein the heat temperature is from about 150° C. to about 240° C.
20. The process of claim 15 further comprising the step of embossing the batt.
21. The process of claim 15 wherein in step (d) heat is applied from above and below the batt.
22. A process for forming a portion of a surface covering comprising the steps of:
(a) conveying a dispersion of low-melt thermoplastic components and high-melt thermoplastic components into a chute feeder, wherein the low-melt thermoplastic component has a melting temperature of at least about 20° C. below melting temperatures for the high-melt thermoplastic components;
(b) maintaining about 20% to about 65% of the dispersion as the low-melt thermoplastic components;
(c) forming a batt with the dispersion;
(d) applying heat from above or below the batt, wherein the heat temperature is below the melting temperatures for high-melt components;
(e) applying pressure to the batt to compact the batt to form a sheet; and
(f) cooling the sheet,
wherein the thermoplastic components comprise fibers and the dispersion are arranged into a plurality of strata of fibers.
23. The process of claim 22 , wherein the batt weighs about 10 oz/yd 2 to about 50 oz/yd 2 .
24. The process of claim 22 , wherein the sheet has a density in the range of about 0.05 to about 0.25 g/cm 3 .
25. The process of claim 22 , wherein before step (a) the dispersion is produced by shredding a fibrous floor covering.
26. The process of claim 25 , wherein the fibrous floor covering comprises a laminated composite or tufted carpet.
27. The process of claim 25 , wherein the fibrous floor covering comprises a post-industrial or post-consumer floor covering that contains substantially no thermoset polymer.
28. The process of claim 25 , wherein the fibrous floor covering comprises a post-industrial or post-consumer floor covering that contains at least some thermoset polymer, dirt, or dust, and wherein before step (a) the thermoset binders, dirt, or dust are pneumatically or centrifugally extracted or filtered out of the dispersion.
29. The process of claim 22 further comprising a step of adding a fibrous face layer or a step of adding an adhesive layer.
30. The process of claim 29 , wherein the fibrous face layer or adhesive layer is added after step (f).
31. The process of claim 29 , wherein the fibrous face layer or adhesive layer is added after step (c).
32. The process of claim 22 , wherein the heat temperature is from about 150° C. to about 240° C.
33. The process of claim 22 further comprising the step of embossing the batt.
34. The process of claim 22 , wherein the sheet is reinforced by attaching a reinforcing layer to the sheet after step (f).
35. The process of claim 22 further comprising a step of aligning said strata of fibers substantially vertically relative to the plane of the batt.
36. The process of claim 35 , wherein the step of aligning comprises a step of turning said strata about 90 degrees.
37. The process of claim 22 , wherein in step (d) heat is applied from above and below the batt.
38. The process of claim 22 further comprising the step of adding a layer to any one side of the sheet.