Article with controlled cushioning

Patent metadata

Field	Value
Publication number	US-9243104-B2
Application number	US-201313838836-A
Country	US
Kind code	B2
Filing date	Mar 15, 2013
Priority date	Mar 15, 2013
Publication date	Jan 26, 2016
Grant date	Jan 26, 2016

Abstract

Pellets, beads, particles, or other pieces of a thermoplastic elastomer having a maximum size in at least one dimension of 10 mm or less (collectively, “pellets”) are infused with a supercritical fluid in a pressurized container, then rapidly depressurized and heated either by immersion in a heated fluid or with infrared or microwave radiation to foam the pellets The pellets are prepared with at least two different densities. Pellets with different densities, thermoplastic elastomer compositions, or foam response rates are placed in different areas of a mold. The mold is filled with pellets, then the pellets are molded into a part. The part has areas of different density as a result of the placement of pellets of different density.

First claim

What is claimed is:

1. A method of forming a molded article of a thermoplastic elastomer having areas of different density, comprising
(a) preparing pellets of a thermoplastic elastomer having a first density by infusing the pellets with a supercritical fluid in a pressurized container, removing the pellets from the container and foaming the pellets by one of (i) heating the pellets with a fluid or (ii) irradiating the pellets with infrared or microwave radiation to make foamed pellets of a first density;
(b) preparing pellets of the thermoplastic elastomer having a second density by infusing the pellets with a supercritical fluid in a pressurized container, removing the pellets from the container and foaming the pellets by one of (i) heating the pellets with a fluid or (ii) irradiating the pellets with infrared or microwave radiation to make foamed pellets of a second density different from the first density;
(c) placing foamed pellets having the first density in a first area of a mold and placing foamed pellets having the second density in a second area of the mold and molding the pellets to form the molded article,
further comprising annealing the foamed pellets made in one or both of steps (a) and (b) before molding in step (c).

2. A method according to claim 1 , wherein the thermoplastic elastomer is selected from the group consisting of thermoplastic polyurethane elastomers, thermoplastic polyester elastomers, thermoplastic polyurea elastomers, thermoplastic polyamide elastomers, metallocene-catalyzed block copolymer elastomers of ethylene and α-olefins having 4 to about 8 carbon atoms, styrene block copolymer elastomers, and combinations thereof and wherein the pellets are a maximum of 10 mm or less in at least one dimension and the molded article is a midsole.

3. A method according to claim 1 , wherein the pellets of step (a) are soaked in the supercritical fluid of step (a) for a length of time different from that for which the pellets of step (b) are soaked in the supercritical fluid of step (b).

4. A method according to claim 1 , wherein the supercritical fluid of step (a) comprises a different amount of a polar liquid than does the supercritical fluid of step (b).

5. A method according to claim 1 , wherein the supercritical fluid of step (a) comprises a polar liquid having a different Hildebrand solubility parameter than that of a polar liquid of the supercritical fluid of step (b).

6. A method according to claim 1 , wherein the pellets in step (a) are soaked in the supercritical fluid for a different length of time, at a different temperature, or under a different pressure compared to the pellets in step (b).

7. A method according to claim 1 , wherein the pellets in step (a) are infused with a non-foaming liquid before being infused with the supercritical fluid and the pellets in step (b) are not infused with a non-foaming liquid before being infused with the supercritical fluid.

8. A method according to claim 1 , wherein the pellets in step (a) are heated with a fluid having a first temperature and the pellets in step (b) are either heated with a fluid having a second temperature different from the first temperature or, when the fluid is a gas, heated with the gas having the first temperature for a different length of time.

9. A method according to claim 1 , wherein the pellets in step (a) are irradiated with infrared or microwave radiation for a first length of time and the pellets in step (b) are irradiated with infrared or microwave radiation for a second length of time different from the first length of time.

10. A method according to claim 1 , wherein at least a part of the supercritical fluid absorbed by the pellets in step (a) is allowed to desorb before the pellets are foamed by step (a)(i), (a)(ii), or (a)(iii) while the pellets in step (b) are foamed immediately after the removing step.

11. A method according to claim 1 , wherein the molded article is a midsole.

12. A method according to claim 11 , wherein the first density is higher than the second density, and further wherein pellets of the first density are placed in a heel area of the midsole and pellets of the second density are place in a plantar area of the midsole.

13. A method according to claim 1 , wherein the supercritical fluid comprises a nucleating agent.

14. A method according to claim 13 , wherein the supercritical fluid is carbon dioxide and the nucleating agent comprises nitrogen.

15. A method of forming a molded article of a thermoplastic elastomer, comprising
(a) preparing pellets of a first thermoplastic elastomer composition by infusing the pellets with a supercritical fluid in a pressurized container, removing the pellets from the container and foaming the pellets by one of (i) heating the pellets with a fluid or (ii) irradiating the pellets with infrared or microwave radiation to make foamed pellets of the first thermoplastic elastomer composition;
(b) preparing pellets of a second thermoplastic elastomer composition different from the first thermoplastic elastomer by infusing the pellets with a supercritical fluid in a pressurized container, removing the pellets from the container and foaming the pellets by one of (i) heating the pellets with a fluid or (ii) irradiating the pellets with infrared or microwave radiation to make foamed pellets of the second thermoplastic elastomer composition;
(c) placing foamed pellets having the first thermoplastic elastomer composition in a first area of a mold and placing foamed pellets having the second thermoplastic elastomer composition in a second area of the mold, wherein the first thermoplastic elastomer composition is different from the second thermoplastic elastomer composition, and molding the pellets to form the molded article,
further comprising annealing the foamed pellets made in one or both of steps (a) and (b) before molding in step (c).

16. A method according to claim 15 , wherein the molded article is a midsole.

17. A method of forming a molded article of a thermoplastic elastomer, comprising
(a) preparing pellets of a first foam response rate by infusing the pellets with a supercritical fluid in a pressurized container, removing the pellets from the container and foaming the pellets by one of (i) heating the pellets with a fluid or (ii) irradiating the pellets with infrared or microwave radiation to make foamed pellets of the first foam response rate;
(b) preparing pellets of a second foam response rate by infusing the pellets with a supercritical fluid in a pressurized container, removing the pellets from the container and foaming the pellets by one of (i) heating the pellets with a fluid or (ii) irradiating the pellets with infrared or microwave radiation to make foamed pellets of the second foam response rate;
(c) placing foamed pellets having the first foam response rate in a first area of a mold and placing foamed pellets having the second foam response rate in a second area of the mold, wherein the first foam response rate is different from the second foam response rate, and molding the pellets to form the molded article,
further comprising annealing the foamed pellets made in one or both of steps (a) and (b) before molding in step (c).

18. A method according to claim 17 , wherein the molded article is a midsole.

Assignees

• Nike Inc

Inventors

• Watkins Richard L
• Baghdadi Hossein
• Edwards Charles
• Chang Yihua

Classifications

• C08J2203/06

  CO2, N2 or noble gases · CPC title

• C08L75/04

  Polyurethanes · CPC title

• B29D35/122

  Soles · CPC title

• A43B13/188

  Differential cushioning regions · CPC title

• A43B13/16

  Pieced soles (with several layers of different material A43B13/12) · CPC title