Process for producing foam panels for the production of foam films

Patent metadata

Field	Value
Publication number	US-11833703-B2
Application number	US-202118250824-A
Country	US
Kind code	B2
Filing date	Oct 12, 2021
Priority date	Oct 29, 2020
Publication date	Dec 5, 2023
Grant date	Dec 5, 2023

Abstract

A process can be used for producing foam panels, for the production of foam films, composed of a polymer having a glass transition temperature T g of at least 100° C. An average cell diameter of the foam panels measured according to the standard ASTM D 3576 is between 20 μm and 250 μm, and less than 20 cells having a diameter >260 μm are present per m 2 . The elongation at break of the foam is 4%-13% measured according to ASTM D 638.

First claim

The invention claimed is:

1. A process for producing foam panels for the production of foam films, consisting of at least one polymer having a glass transition temperature T g of at least 100° C., an average cell diameter measured according to the standard ASTM D 3576 between 20 μm and 250 μm and less than 20 cells having a diameter >260 μm per m 2 , and an elongation at break of the foam panels between 4%-13% measured according to ASTM D 638,
the process comprising:
A) removing a foam skin of a foam block, and
B) cutting a remaining portion of the foam block into foam panels having thicknesses between 60 and 135 mm.

2. The process according to claim 1 , wherein the at least one polymer has a glass transition temperature of at least 140° C.

3. The process according to claim 1 , wherein the at least one polymer is selected from the group consisting of polyether sulfone, polyphenyl sulfone, polyether ether ketone, poly(meth)acrylimide, polymethyl (meth)acrylate, polyetherimide, polysulfone, polyurethane, polyethylene terephthalate, and mixtures and copolymers thereof.

4. The process according to claim 1 , wherein the average cell diameter of the foam panels is between 50 μm and 220 μm.

5. The process according to claim 1 , wherein less than 15 cells having a cell diameter >260 μm are present per m 2 of the foam panel.

6. The process according to claim 1 , wherein the elongation at break of the foam panel is 5%-10%, measured according to ASTM D 638.

7. The process according to claim 1 , wherein the foam skin of the foam block in A) has a thickness of 3 mm.

8. The process according to claim 1 , wherein the foam panels in B) are cut using a band knife or band saw.

9. The process according to claim 4 , wherein the average cell diameter of the foam panels is between 80 μm to 200 μm.

Assignees

• Evonik Operations Gmbh

Inventors

• Goldmann Felix
• Richter Thomas
• Roth Matthias Alexander
• Becker Florian
• Pinto Jorge Manuel

Classifications

• C08J9/38

  Destruction of cell membranes · CPC title

• B29C2793/0027

  Cutting off · CPC title

• B29C2793/009

  after shaping · CPC title

• C08J2379/08

  Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors · CPC title

• B26D3/006 Primary

  specially adapted for cutting blocs of plastic material · CPC title