METHOD TO RECYCLE A FIBROUS CARPET PRODUCT
The present invention pertains to a method for recycling a carpet product, the carpet product comprising a fibrous sheet comprising polymer yarns, wherein at least one surface of the sheet is provided with a layer of polymer adhesive, wherein the carpet product is a substantially pure polyester carpet product, wherein the polymer yarns comprise polyester having a molecular weight above 50,000 g/mol and a melting point between 180 and 300° C., the adhesive is a polyester adhesive having a crystallinity between 5% and 35% and a viscosity of 5-55 Pa·s at 150° C., the method comprising homogenising the carpet product by extrusion. The invention also pertains to recycled polymer obtainable by this method, to fibres comprising this recycled polymer material, to fibrous products comprising these fibres and to polyester adhesive.
1 . Method for recycling a carpet product, the carpet product comprising a fibrous sheet comprising polymer yarns, wherein at least one surface of the sheet is provided with a layer of polymer adhesive, wherein the carpet product is a substantially pure polyester carpet product, wherein the polymer yarns comprise polyester having a molecular weight above 50,000 g/mol and a melting point between 180 and 300° C., the adhesive is a polyester adhesive having a crystallinity between 5% and 35% and a viscosity of 5-55 Pa·s at 150° C., the method comprising homogenising the carpet product by extrusion.
2 . Method according to claim 1 , wherein the amount of polyester adhesive is between 0.5 and 25% w/w with regard to the total amount of polyester in the carpet product.
3 . Method according to claim 1 , wherein the amount of polyester adhesive is at least 1% w/w with regard to the total amount of polyester in the carpet product.
4 . Method according to claim 1 , wherein the amount of polyester adhesive is between 2% and 20% w/w, optionally between 5 and 15% w/w, with regard to the total amount of polyester in the carpet product.
5 . Method according to claim 1 , wherein the carpet product is mechanically cut into pieces having dimensions below 20 cm in width and length, wherein the carpet product pieces are compressed before being fed to an extruder to be homogenised.
6 . Method according to claim 5 , wherein the carpet product pieces are compressed to reach a bulk density of at least 0.3 g/cm 3 , preferably at least 0.5 g/cm 3 .
7 . Method according to claim 5 , wherein the carpet product pieces are compressed at an elevated temperature between room temperature and the melting temperature of the polyester adhesive.
8 . Method according to claim 7 , wherein the carpet product pieces are compressed at a temperature between 80-100° C.
9 . Method according to claim 1 , wherein the fibrous sheet comprises a primary backing having polyester yarns stitched therein to form a pile on a front surface of this primary backing and loops at an opposite back surface of the primary carrier, the polyester adhesive being applied to the back surface of the primary carrier.
10 . Method according to claim 9 , wherein the carpet product is made by contacting the back surface of the primary carrier with a surface of a hot body to at least partly melt the loops of the yarns to create a mass of molten material before the polyester adhesive is applied to this back surface.
11 . A method according to claim 10 , wherein the carpet product is made by providing the surface of the hot body at a relative speed with respect to back surface of the primary carrier, in particular by providing the surface of the hot body as a stationary object, the primary carrier being transported along the hot body.
12 . Recycled polyester obtainable by a method according to claim 1 .
13 . Fibres comprising the polyester material of claim 12 .
14 . Fibrous products comprising the fibres according to claim 13 .
15 . A polyester adhesive having a crystallinity between 5% and 35% and a viscosity of 5-55 Pa·s at 150° C.