Low density foam, midsole, footwear, and methods for making low density foam

Patent metadata

Field	Value
Publication number	US-9926423-B2
Application number	US-201313958517-A
Country	US
Kind code	B2
Filing date	Aug 2, 2013
Priority date	Aug 2, 2013
Publication date	Mar 27, 2018
Grant date	Mar 27, 2018

Abstract

Foamed thermoplastic elastomeric polyurethane and ethylene-vinyl acetate copolymer articles are made with a combination of a supercritical fluid and a non-supercritical fluid blowing agent.

First claim

What is claimed is:

1. A method for making a low density foamed article, comprising:
combining in an extruder a molten thermoplastic polyurethane elastomer with
(a) a chemical blowing agent and
(b) a supercritical fluid,
to form a mixture, wherein the chemical blowing agent (a) is present in an amount up to about 15 wt % based on total polymer weight in the mixture and the supercritical fluid (b) comprises one of about 0.1 to about 5 weight percent of supercritical CO 2 based on the total polymer weight in the mixture or about 0.1 to about 4 weight percent of supercritical N 2 based on the total polymer weight in the mixture, and
injecting the mixture into a mold at an injection pressure of from 110 MPa to about 207 MPa, and molding the mixture to form the low density foamed article, wherein the mold comprises a porous tool;
wherein the low density foamed article has a density of less than 0.3 g/cm 3 .

2. A method according to claim 1 , wherein the molten thermoplastic polyurethane elastomer comprises a thermoplastic polyurethane elastomer having a solid Shore A hardness of from about 35 A to about 85 A.

3. A method according to claim 2 , wherein the solid Shore A hardness is from about 50 A to about 80 A.

4. A method according to claim 1 , wherein the chemical blowing agent is present in an amount from about 3 to about 12 wt % based on the total polymer weight in the mixture.

5. A method according to claim 1 , wherein the supercritical fluid is one of from about 0.5 to about 3 weight percent of supercritical CO 2 based on the total polymer weight in the mixture or from about 0.4 to about 2.5 weight percent of supercritical N 2 based on the total polymer weight in the mixture.

6. A method according to claim 1 , wherein the mixture further comprises a crosslinker.

7. A method according to claim 1 , wherein the porous tool has a pore size of from about 3 micrometers to about 20 micrometers.

8. A method according to claim 1 , wherein the porous tool is a porous metal or metal alloy.

9. A method according to claim 1 , wherein the porous tool is an insert having dimensions of the mold cavity.

10. A method according to claim 1 , wherein the porous tool comprises a plurality of inserts spaced within the mold cavity.

11. A method for making a low density foamed article, comprising:
combining in an extruder a molten thermoplastic polyurethane elastomer having a solid Shore A hardness of from about 35 A to about 85 A and a melt index of from about 5 to about 100 grams/10 min. as measured according to ASTM D1238 using an 8.7 kg weight and a temperature of 190° C. or from about 180 to about 300 grams/10 min. as measured according to ASTM D1238 using a 21.6 kg weight and a temperature of 200° C. with
(a) a chemical blowing agent and
(b) a supercritical fluid
to form a mixture, wherein the chemical blowing agent (a) is present in an amount up to 15 wt % based on total polymer weight in the mixture and the supercritical fluid (b) comprises one of about 0.1 to about 5 weight percent of supercritical CO 2 based on the total polymer weight in the mixture or about 0.1 to about 4 weight percent of supercritical N 2 based on the total polymer weight in the mixture, and
injecting the mixture into a mold at an injection pressure of from 110 MPa to about 207 MPa, and molding the mixture to form the low density foamed article.

12. A method according to claim 11 , wherein the Shore A hardness is from about 50 A to about 80 A.

13. A method according to claim 11 , wherein the or chemical blowing agent is present in an amount from about 3 to about 12 wt % based on the total polymer weight in the mixture.

14. A method according to claim 11 , wherein the supercritical fluid is one of from about 0.5 to about 3 weight percent of supercritical CO 2 based on the total polymer weight in the mixture or from about 0.4 to about 2.5 weight percent of supercritical N 2 based on the total polymer weight in the mixture.

15. A method for making a low density foamed article, comprising:
combining in an extruder a molten polymer thermoplastic polyurethane elastomer having a melt index of from about 5 to about 100 grams/10 min. as measured according to ASTM D1238 using an 8.7 kg weight and a temperature of 190° C., or from about 180 to about 300 grams/10 min. as measured according to ASTM D1238 using a 21.6 kg weight and a temperature of 200° C. with
(a) a chemical blowing agent and
(b) a supercritical fluid
to form a mixture, wherein the chemical blowing agent is present in an amount up to 15 wt % based on total polymer weight in the mixture and the supercritical fluid comprises one of about 0.1 to about 5 weight percent of supercritical CO 2 based on the total polymer weight in the mixture or about 0.1 to about 4 weight percent of supercritical N 2 based on the total polymer weight in the mixture, and
injecting the mixture into a mold at an injection pressure of from 110 MPa to about 207 MPa, and molding the mixture to form the low density foamed article; wherein the mold comprises a porous tool;
wherein the low density foamed article has a density of less than 0.3 g/cm 3 .

16. A method according to claim 15 , wherein the molten polymer comprises a thermoplastic polyurethane elastomer having a solid Shore A hardness of from about 35 A to about 85 A.

17. A method according to claim 15 , wherein the chemical blowing agent is present in an amount from about 3 to about 12 wt % based on the total polymer weight.

18. A method according to claim 15 , wherein the supercritical fluid is one of from about 1 to about 3 weight percent of supercritical CO 2 based on the total polymer weight in the mixture or from about 0.4 to about 2.5 weight percent of supercritical N 2 based on the total polymer weight in the mixture.

19. A method according to claim 15 , wherein the porous tool has a pore size of from about 3 micrometers to about 20 micrometers.

20. A method according to claim 15 , wherein the porous tool is a porous metal or metal alloy.

21. A method according to claim 15 , wherein the porous tool is an insert that is generally the dimensions of the mold cavity.

22. A low density foamed article made by the method of claim 1 .

23. The low density foamed article according to claim 22 , wherein the article has a density of from about 0.15 to less than 0.3 g/cm 3 .

24. The low density foamed article according to claim 22 , wherein the article is a cushion or cushioning element for an article of footwear, protective equipment, or clothing.

Assignees

• Nike Inc

Inventors

• Baghdadi Hossein A

Classifications

• C08J2375/08

  from polyethers · CPC title

• C08J2201/024

  Preparation or use of a blowing agent concentrate, i.e. masterbatch in a foamable composition · CPC title

• B29C44/3446 Primary

  Feeding the blowing agent · CPC title

• C08J2203/182

  of physical blowing agents, e.g. acetone and butane · CPC title

• C08J2475/06

  from polyesters · CPC title