Foaming process for production of foam materials

Patent metadata

Field	Value
Publication number	US-11904514-B2
Application number	US-201917310059-A
Country	US
Kind code	B2
Filing date	Dec 19, 2019
Priority date	Jan 16, 2019
Publication date	Feb 20, 2024
Grant date	Feb 20, 2024

Abstract

A production process can produce foam materials from polymer compositions. This process involves preheating in the foaming of polymers containing blowing agents and subsequent foaming by a thermal process assisted by microwaves.

First claim

The invention claimed is:

1. A process for producing a foam, comprising:
preheating a polymer composition to be foamed, and
foaming the polymer composition containing a blowing agent in an apparatus having a thermal heating device for heating to an internal temperature of the apparatus Ts and irradiating simultaneously the polymer composition by at least one microwave source of the apparatus:
wherein the polymer composition, prior to the foaming, is preheated to a preheating temperature T v above a glass transition temperature T g of the polymer composition.

2. The process according to claim 1 , wherein the polymer composition is preheated in the apparatus at a temperature between a minimum of 80° C. below and a maximum of 10° C. above the internal temperature of the apparatus T S .

3. The process according to claim 1 , wherein a temperature differential between a coldest point and a hottest point within the polymer composition after the preheating is not greater than 15° C.

4. The process according to claim 1 , wherein the preheated polymer composition is supplied directly to the foaming process in the apparatus.

5. The process according to claim 1 , wherein the polymer composition is a material that forms a rigid foam after the foaming.

6. The process according to claim 1 , wherein a preheating temperature Tv is between 110 and 190° C., and a preheating time is at least 85 min.

7. The process according to claim 1 , wherein microwave radiation from the at least one microwave source has a frequency between 0.85 and 6.0 GHz.

8. The process according to claim 1 , wherein the polymer composition comprises PMI (polymethacrylimide), wherein a preheating temperature T V is between 120 and 190° C., and wherein an internal temperature of the apparatus T S is between 180 and 240° C.

9. The process according to claim 1 , wherein the polymer composition comprises PMMA or methacrylate-based copolymer, werein a preheating temperature T V is between 110 and 140° C., and wherein an internal temperature of the apparatus T S is between 120 and 190° C.

10. The process according to claim 5 , wherein the rigid foam is selected from the group selecting of P(M)I (poly(meth)acrylimide), PMMA, a methactylate-based copolymer, polyvinyl chloride (PVC), polypropylene (PP), polyurethane (PU), a polysulfone, and a poly(ether)imide.

11. The process according to claim 6 , wherein the preheating time is at least 110 min.

12. The process according to claim 1 , wherein a preheating time is at least 70 min.

13. The process according to claim 1 , wherein a preheating time is at least 80 min.

Assignees

• Evonik Operations Gmbh

Inventors

• Richter Thomas
• Liebe Andreas
• Trassl Christian
• Becker Florian
• Ma Junyong Vincent

Classifications

• B29C44/3415 Primary

  Heating or cooling · CPC title

• B29C35/0805

  using electromagnetic radiation · CPC title

• B29C2035/0855

  using microwave · CPC title

• B29K2105/04

  cellular or porous · CPC title

• B29C44/60

  Measuring, controlling or regulating · CPC title