Method for producing foam particles made of thermoplastic elastomers with polyamide segments

Patent metadata

Field	Value
Publication number	US-12234338-B2
Application number	US-201716311888-A
Country	US
Kind code	B2
Filing date	Jun 21, 2017
Priority date	Jun 23, 2016
Publication date	Feb 25, 2025
Grant date	Feb 25, 2025

Abstract

A process for producing foam particles composed of thermoplastic elastomers having polyamide segments, comprising the steps:
(a) production of a suspension of pellets of the thermoplastic elastomer in a suspension medium, (b) addition of a blowing agent, (c) impregnation of the pellets with the blowing agent by heating of the suspension in a pressure vessel to an impregnation temperature IMT at an impregnation pressure IMP, depressurization of the suspension by emptying of the pressure vessel via a depressurization device and work-up of the foam particles obtained, and also foam particles obtainable by the process.

First claim

The invention claimed is:

1. A process for producing foam particles composed of one or more thermoplastic elastomers having polyamide segments, the process comprising:
adding a blowing agent to a suspension of pellets of a polymer in a suspension medium;
impregnating the pellets with the blowing agent by heating the suspension in a pressure vessel to an impregnation temperature IMT, which is from 80 to 180° C., at an impregnation pressure IMP in the range of from 500 to 3010 kPa absolute;
depressurizing the suspension by emptying the pressure vessel with a depressurization device, thereby obtaining foam particles; and
obtaining a foam molding by fusing the foam particles with steam at a gauge pressure of from 80 to 150 kPa,
wherein the polymer content in the pellets consists of the one or more thermoplastic elastomers having polyamide segments;
wherein the process is a batchwise process;
(a) wherein the blowing agent consists of carbon dioxide;
(b) wherein the foam particles have a bulk density of from 20 to 250 kg/m 3 ;
wherein the impregnating by heating the suspension, is followed by keeping the suspension at a temperature of from 2° C. above the impregnation temperature (IMT) to 5° C. below the impregnation temperature (IMT) for a period of from 2 to 100 minutes;
wherein the blowing agent is used in amounts of from 1 to 50% by weight, based on the weight of the pellets;
wherein the thermoplastic elastomer having polyamide is a polyether block amide (PEBA);
wherein the PEBA consists of flexible polytetrahydrofuran and crystalline polyamide 12 units; and
wherein the PEBA has 19.8 to 25.4% by weight polyamide blocks.

2. The process according to claim 1 , wherein the pellets have an average mass of from 1 to 50 mg.

3. The process according to claim 1 , wherein the suspension medium comprises water.

4. The process according to claim 1 , wherein the depressurizing of the suspension is effected by emptying the pressure vessel with a ball valve into an expansion vessel.

5. The process according to claim 1 , wherein, during the depressurizing, the suspension is brought into contact with a liquid coolant downstream of the depressurization device.

6. The process according to claim 1 , wherein the foam molding has a ball rebound resilience of at least 55%, as measured in accordance with DIN EN ISO 8307.

7. The process according to claim 1 , wherein the foam molding has a bulk density of 200 to 300 kg/m 3 .

8. The process according to claim 1 , wherein the foam particles have a bulk density of 120 to 250 kg/m 3 .

9. The process according to claim 1 , wherein the foam particles have a bulk density of 150 to 250 kg/m 3 .

10. The process according to claim 1 , wherein the suspension is kept at a temperature of from 2° C. above the impregnation temperature (IMT) to 5° C. below the impregnation temperature (IMT) for a period of from 2 to 20 minutes.

11. The process according to claim 1 , wherein the blowing agent is used in an amount of 12-50% by weight of the pellets.

Assignees

• Basf Se

Inventors

• Keppeler Uwe
• Bartl Juergen
• Ahlers Juergen
• Daeschlein Christian
• Gutmann Peter
• Prissok Frank

Classifications

• C08J2377/00

  Characterised by the use of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Derivatives of such polymers · CPC title

• C08J2201/034

  Post-expanding of foam beads or sheets · CPC title

• C08J2201/032

  Impregnation of a formed object with a gas · CPC title

• C08G69/40

  Polyamides containing oxygen in the form of ether groups (C08G69/12, C08G69/32 take precedence) · CPC title

• C08J2300/22

  Thermoplastic resins · CPC title