Separation of floor covering components for recycling
View Patent ↗The invention relates to methods for processing floor coverings ( 100 ), such as carpet and/or carpet tile, having at least one layer containing a polyurethane ( 104 ), such that at least this polyurethane—containing layer ( 104 ) can be recycled and reused. The method involves contacting the floor covering ( 100 ) with an organic polyol ( 110 ) and heating ( 120 ) it, so that the polyurethane—containing layer ( 104 ) softens and/or partially liquefies, but can be resolidified by contact with additional polyisocyanate ( 140 ).
1. A method for processing a floor covering comprising a facecloth layer, a backing layer, and optionally an adhesive or precoat layer, wherein the floor covering comprises at least one layer containing a polyurethane formed by reacting a polyisocyanate and a first organic polyol, which comprises:
contacting the floor covering with a second organic polyol_by disposing said second organic polyol onto the facecloth layer of the floor covering,
heating the floor covering and second organic polyol by increasing the temperature of the floor covering and second organic polyol sufficiently to at least partially liquefy the polyurethane; and
separating the facecloth layer from the backing layer by pulling said facecloth away from said backing layer.
2. The method of claim 1 , wherein the backing layer is contacted with a material containing additional polyisocyanate and adhered to a second facecloth, to form a second floor covering.
3. The method of claim 1 , wherein the backing layer comprises a urethane-modified bitumen.
4. The method of claim 1 , wherein said first and second organic polyols are the same.
5. The method of claim 1 , further comprising contacting said facecloth layer with a second backing layer.
6. The method of claim 1 , wherein the layer containing the polyurethane is disposed between a precoat layer and the backing layer.
7. The method of claim 1 , wherein the backing layer comprises foamed polyurethane, and wherein the backing layer is the layer containing the polyurethane to be liquefied.
8. The method of claim 7 , wherein the liquefied polyurethane obtained from the backing layer is refoamed with added polyisocyanate.
9. A method for processing a floor covering comprising a facecloth layer, a backing layer, and optionally an adhesive or precoat layer, wherein the floor covering comprises at least one layer containing a polyurethane formed by reacting a polyisocyanate and a first organic polyol, which comprises:
contacting the floor covering with a second organic polyol;
heating the floor covering and second organic polyol;
separating the facecloth layer from the backing layer; and
reconstituting the backing layer by contacting it with additional polyisocyanate.
10. The method of claim 9 , wherein said first organic polyol and said second organic polyol are the same.
11. The method of claim 9 , wherein said heating comprises increasing the temperature of the floor covering and second organic polyol sufficiently to at least partially liquefy the polyurethane.
12. The method of claim 11 , wherein said contacting comprises grinding floor covering into smaller pieces and mixing these pieces with said second organic polyol.
13. The method of claim 12 , wherein said polyurethane-containing layer is the backing layer or the adhesive or precoat layer, or both.
14. The method of claim 13 , wherein the polyurethane-containing layer comprises a urethane-modified bitumen.