Method of making foams using partial molds

• US 10,730,231 B2
• Filed: 09/03/2018
• Issued: 08/04/2020
• Est. Priority Date: 11/05/2014
• Status: Active Grant

• Current Assignee: Nike, Inc.
• Original Assignee: Nike, Inc.
• Inventors: Farris, Bryan N., Turner, David
• Primary Examiner(s): Boyle, Kara B
• Application Number:
  US16/120,395
• Publication Number:
  US 20180370115A1
• Time in Patent Office: 701 Days
• CPC Class Codes: B29C 35/02 Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mouldcold vulcanisation B29C35/18 ; vulcanising tyres, presses therefor B29D30/0601
• CPC Class Codes: B29C 44/3453 Feeding the blowing agent to solid plastic material
• CPC Class Codes: B29C 44/348 by regulating the temperature and/or the pressure, e.g. suppression of foaming until the pressure is rapidly decreased
• CPC Class Codes: B29C 64/00 Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
• CPC Class Codes: B29C 64/106 using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
• CPC Class Codes: B29C 64/118 using filamentary material being melted, e.g. fused deposition modelling [FDM]
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing

Abstract

A method of making a foamed article, for example a foamed component for an article or footwear, comprises depositing an unfoamed, thermoplastic polymer onto a support surface in a three-dimensional printing process to form an unfoamed article; heating the article to soften the article and infusing the softened article with at least one inert gas at a first pressure greater than atmospheric pressure that is sufficient to cause the at least one inert gas to permeate into the softened article; and reducing the pressure to second pressure below the first pressure while the article is softened to at least partially foam the article, wherein a surface of a partial mold limits foam expansion in at least one direction but less than all directions. The article or a part of the article may be made by printing a thermoplastic polymeric material with a three-dimensional printer in a structure of interconnected, unfoamed, thermoplastic polymeric members spaced to define openings between the thermoplastic polymeric members.

Claims

1. A method of making a closed-cell foamed article comprising

a) forming an unfoamed article at a first location using a three-dimensional printing process, the unfoamed article comprising unfoamed, thermoplastic polymer deposited as interconnected, unfoamed, thermoplastic polymeric members spaced to define openings therebetween;

b) heating the unfoamed article to a first temperature to soften the unfoamed article and infusing the softened unfoamed article with at least one inert gas at a first pressure that is sufficient to cause the at least one inert gas to permeate into the softened unfoamed article;

c) cooling the unfoamed article to a second temperature and reducing the pressure to a second pressure;

d) transferring the cooled unfoamed article to a partial mold at a second location; and

e) heating the unfoamed article in the partial mold to a third temperature to soften the unfoamed article and at least partially foam the unfoamed article, wherein pressure is adjusted to a third pressure sufficient to allow the infused inert gas to partition out of the softened unfoamed article to at least partially foam the unfoamed article into a foamed article, and wherein a surface of a partial mold limits foam expansion in at least one direction but less than all directions.

2. A method according to claim 1, wherein the third temperature is the same as the first temperature.

3. A method according to claim 1, wherein the third temperature is different from the first temperature.

4. A method according to claim 1, wherein the pressure is greater than atmospheric during heating of the unfoamed article to the third temperature and is reduced to the third pressure less than the second pressure after heating to the third temperature to at least partially foam the unfoamed article.

5. A method according to claim 1, wherein the surface of the partial mold that limits foam expansion is flat and optionally includes one or more spaces through which the unfoamed article can expand beyond the surface during foaming.

6. A method according to claim 1, wherein outer surfaces of the unfoamed article before the foaming step define a top, a bottom opposite the top, and an outer circumference between the top and the bottom;

and further wherein the partial mold limits foam expansion of at least a part of the outer circumference.

7. A method according to claim 6, wherein the partial mold limits foam expansion to expansion in directions of the top and the bottom.

8. A method according to claim 1, wherein the partial mold has a bottom surface and side surfaces that limit foam expansion and is open in a direction opposite the bottom surface.

9. A method according to claim 8, wherein the partial mold has a first mold part comprising the bottom surface and a second mold part comprising the side surfaces, wherein the first mold part and the second mold part are adjacent but not conjoined.

10. A method according to claim 9, further comprising after step e) moving the second mold part away from the first mold part before unmolding the foamed article from the second mold part.

11. A method according to claim 1, wherein the partial mold has a surface that imparts a pattern or decoration on at least a portion of the foamed article.

12. A method according to claim 1, wherein the partial mold comprises a bottom portion and a side portion.

13. A method according to claim 12, wherein the side portion incompletely surrounds the unfoamed article.

14. A method according to claim 12, wherein the partial mold is in a shape of a midsole for footwear.

15. A method according to claim 1, wherein the partial mold comprises adjacent sections that separate during foaming and while forming the foamed article.

16. A method according to claim 1, wherein a portion of the partial mold becomes attached to the foamed article.

17. A method according to claim 16, wherein the foamed article is a midsole for footwear having a first major surface and a second major surface opposite the first major surface, wherein the portion of the partial mold becomes attached to the first major surface or to the second major surface.

18. A method according to claim 1, wherein at least a portion of the interconnected, unfoamed, thermoplastic polymeric members are arranged in a repeating pattern comprising repeating units.

19. A method according to claim 18, wherein the repeating pattern repeats in two directions perpendicular to one another.

20. A method according to claim 18, wherein the repeating units are uniform.