Foams based on thermoplastic polyurethanes

Patent metadata

Field	Value
Publication number	US-11292886-B2
Application number	US-202017031220-A
Country	US
Kind code	B2
Filing date	Sep 24, 2020
Priority date	Jan 18, 2006
Publication date	Apr 5, 2022
Grant date	Apr 5, 2022

Abstract

Expandable thermoplastic polyurethane comprising blowing agent, wherein the Shore hardness of the thermoplastic polyurethane is from A 44 to A 84.

First claim

The invention claimed is:

1. A method of making a sole for an article of footwear, the method comprising:
melting thermoplastic polyurethane and a blowing agent in an extruder;
discharging the melted thermoplastic polyurethane and blowing agent from the extruder to form thermoplastic polyurethane beads;
expanding the thermoplastic polyurethane beads; and
fusing the expanded thermoplastic polyurethane beads to one another to form the sole.

2. The method of claim 1 , wherein the thermoplastic polyurethane and the blowing agent are introduced into the extruder together.

3. The method of claim 1 , wherein the thermoplastic polyurethane and the blowing agent are introduced into the extruder separately.

4. The method of claim 1 , wherein the thermoplastic polyurethane and the blowing agent are introduced into the extruder at different locations.

5. The method of claim 1 , wherein the thermoplastic polyurethane and the blowing agent are introduced into the extruder at one location.

6. The method of claim 1 , wherein the extruder comprises a single-screw extruder.

7. The method of claim 1 , wherein the extruder comprises a double-screw extruder.

8. The method of claim 1 , wherein the extruder is operated at a temperature between 150° C. and 250° C.

9. The method of claim 1 , wherein the extruder is operated at a temperature between 180° C. and 210° C.

10. The method of claim 1 , wherein the blowing agent comprises a hydrocarbon.

11. The method of claim 1 , wherein the blowing agent comprises between 0.1% and 40% of the total weight of the thermoplastic polyurethane.

12. The method of claim 1 , wherein the sole comprises a midsole.

13. The method of claim 1 , wherein the expanded thermoplastic polyurethane beads have a diameter between 0.2 mm and 20 mm.

14. The method of claim 1 , wherein the expanded thermoplastic polyurethane beads are spherical.

15. The method of claim 1 , wherein fusing the expanded thermoplastic polyurethane beads to one another to form the sole comprises placing the expanded thermoplastic polyurethane beads in a closed mold and exposing the expanded thermoplastic polyurethane beads to a temperature between 100° C. and 140° C.

16. The method of claim 1 , wherein the expanded thermoplastic polyurethane beads have a density between 5 g/l and 600 g/l.

17. The method of claim 1 , wherein the discharging occurs under temperature and pressure conditions such that the expanding does not occur during the discharging and the thermoplastic polyurethane beads formed by the discharging are expandable thermoplastic polyurethane beads.

18. The method of claim 17 , wherein the discharging occurs under water at a pressure between 2 bar and 20 bar and a temperature between 5° C. and 95° C.

19. The method of claim 1 , wherein the expanding occurs during the discharging.

20. The method of claim 1 , wherein the discharging occurs into conditions that do not inhibit the thermoplastic polyurethane beads from expanding.

21. The method of claim 1 , wherein the discharging occurs directly into atmospheric pressure.

Assignees

• Basf Se

Inventors

• Prissok Frank
• Braun Frank

Classifications

• C08J9/16 Primary

  Making expandable particles · CPC title

• C08J2201/03

  Extrusion of the foamable blend · CPC title

• A43B17/14

  made of sponge, rubber, or plastic materials · CPC title

• B29B9/12

  characterised by structure or composition · CPC title

• C08L75/04

  Polyurethanes · CPC title