Method for producing a foam component

Patent metadata

Field	Value
Publication number	US-12378382-B2
Application number	US-202117170131-A
Country	US
Kind code	B2
Filing date	Feb 8, 2021
Priority date	Feb 7, 2020
Publication date	Aug 5, 2025
Grant date	Aug 5, 2025

Abstract

A method for producing a foam component includes providing a particulate starting material in a mold, softening the starting material, inducing a pressure change within the mold to cause foaming in at least a portion of the softened starting material without the use of a blowing agent, and solidifying the foamed starting material.

First claim

The invention claimed is:

1. A method for producing a foam component, comprising the steps of:
providing a particulate starting material in a mold;
softening the starting material in the mold;
inducing a pressure change within the mold to cause foaming in at least a portion of the softened starting material without the use of a chemical blowing agent, wherein the pressure change comprises a reduction in pressure and wherein the foaming caused by the pressure change reduces the density of the particulate starting material by more than one third; and
solidifying the foamed starting material.

2. The method according to claim 1 , wherein the starting material comprises particles of a size of 0.01 to 3 mm.

3. The method according to claim 1 , wherein the starting material comprises a thermoplastic or crosslinking polymer material.

4. The method according to claim 1 , wherein the softening comprises trapping inclusions of at least one gas between particles of the starting material.

5. The method according to claim 4 , wherein the foaming is caused by expansion of the at least one gas in the inclusions trapped between particles of the softened starting material.

6. The method according to claim 1 , wherein the softening comprises heating the starting material.

7. The method according to claim 6 , wherein the heating of the starting material comprises heating by direct heat input into the starting material or heat input via the mold.

8. The method according to claim 6 , wherein a number of gas inclusions in the softened starting material is adjustable via a temperature profile of the heating.

9. A method for producing a foam component, comprising the steps of:
providing a particulate starting material in a mold;
softening the starting material;
inducing a pressure change within the mold to cause foaming in at least a portion of the softened starting material without the use of a chemical blowing agent, wherein the pressure change comprises a reduction in pressure and wherein the foaming caused by the pressure change reduces the density of the particulate starting material by more than one third; and
solidifying the foamed starting material into a foam component comprising an edge layer that is in contact with the mold and is free of expanded gas inclusions.

10. The method according to claim 9 , wherein the edge layer comprises a thickness of 0.1 to 2.0 mm.

11. The method according to claim 1 , wherein a processing temperature of the starting material is above its melting temperature.

12. The method according to claim 1 , wherein a temperature within the mold is different in at least two regions of the mold.

13. The method according to claim 1 , wherein the pressure change is 0.05 to 5.0 bar.

14. The method according to claim 1 , wherein an initial pressure in the mold before the softening corresponds to atmospheric pressure or overpressure.

15. The method according to claim 14 , wherein the overpressure comprises compressed air or nitrogen.

16. The method according to claim 1 , wherein the inducing of the pressure change comprises inducing the pressure change upon reaching a melting temperature of at least a portion of the starting material.

17. The method according to claim 1 , wherein an absolute value of the pressure change within the mold is different in at least two regions of the mold.

18. The method according to claim 12 , wherein the foaming in each of the at least two regions is individually adjustable by a temperature or pressure difference in the at least two regions within the mold.

19. The method according to claim 1 , wherein foaming is not induced in at least one region of the mold.

20. The method according to claim 1 , wherein the solidifying comprises solidifying after the inducing the pressure change.

21. The method according to claim 1 , wherein the solidifying comprises cooling of the foamed starting material.

22. The method according to claim 1 , wherein a density of the foam component is at least partially adjustable by an amount of the pressure change.

23. The method according to claim 1 , wherein a structure of the foam component is at least partially influenced by at least one of the following properties of the starting material: material of the particles, particle shape, particle size, and particle size distribution.

24. The method according to claim 1 , further comprising introducing a second material into the mold.

25. The method according to claim 24 , wherein the second material comprises a filler or a reinforcing element.

26. The method according to claim 24 , wherein no foaming occurs in the second material.

27. The method according to claim 1 , comprising maintaining the reduction of the pressure while solidifying the foamed starting material.

28. The method of claim 1 , wherein the pressure change is in an amount of 0.05 to 5.0 bar.

29. The method of claim 1 , comprising softening the starting material in the mold to a viscosity in a range of 10 2 to 10 4 Pa-s.

30. The method of claim 1 , comprising softening the starting material in the mold to a viscosity in a range of 10 1 to 10 5 Pa·s.

Assignees

• Adidas Ag

Inventors

• Nürnberg Hans-Peter
• Werner Jannik
• Drummer Dietmar
• Vetter Lukas
• Hertle Sebastian
• Wolf Michael

Classifications

• B29C44/3403

  Foaming under special conditions, e.g. in sub-atmospheric pressure, in or on a liquid · CPC title

• B29C44/0407

  by regulating the temperature of the mould or parts thereof, e.g. cold mould walls inhibiting foaming of an outer layer · CPC title

• C08J9/24

  by surface fusion and bonding of particles to form voids, e.g. sintering (of expandable particles C08J9/232) · CPC title

• C08J9/232

  by sintering expandable particles · CPC title

• C08J2300/00

  Characterised by the use of unspecified polymers · CPC title