PRODUCTION OF HIGH TEMPERATURE POLYMER BASED PELLETS BY UNDERWATER PELLETIZATION AT ELEVATED WATER TEMPERATURE TO PRODUCE (RIGID) BEAD FOAMS

Abstract

A process can be used for producing (rigid) particle foams from polymer compositions containing at least one polymer having a glass transition temperature according to ISO 11357-2 of at least 180° C. with an underwater pelletization system.

Claims

1: A process for producing (rigid) particle foams with an underwater pelletization system from a polymer composition comprising at least one polymer having a glass transition temperature according to ISO 11357-2 (published: 2014-07) of at least 180° C., the process comprising: a) conveying a polymer melt of the polymer composition from an extruder into a first water circuit that is pressurized, with a pressure being within a range from 0.2 to 30 bar and a water temperature in the first water circuit being within a range from 105° C. to 180° C., and b) pelletizing.

2: The process for producing (rigid) particle foams with the underwater pelletization system according to claim 1, further comprising: c) supplying a pelletized material from b) to a second water circuit that has a temperature below 100° C. and is operated 1) unpressurized, or 2) under a pressure within a range from 0.2 to 30 bar.

3: The process for producing (rigid) particle foams according to claim 1, wherein the at least one polymer having a glass transition temperature according to ISO 11357-2 of at least 180° C. is selected from the group consisting of a polysulfone, a polyimide, and a mixture thereof.

4: The process for producing (rigid) particle foams according to claim 1, wherein the polymer composition comprises a blowing agent.

5: The process for producing (rigid) particle foams according to claim 4, wherein the temperature in a) is at least 5° C. below a Tg of the polymer melt containing the blowing agent.

6: The process for producing (rigid) particle foams according to claim 4, wherein the blowing agent is selected from the group consisting of a volatile organic compound having a boiling point at standard pressure below a glass transition temperature of a base material, an inorganic blowing agent, a thermally decomposable blowing agent, and a mixture thereof.

7: The process for producing (rigid) particle foams according to claim 1, wherein the polymer composition comprises a nucleating agent.

8: The process for producing (rigid) particle foams according to claim 7, wherein the nucleating agent is selected from the group consisting of talc, graphite, carbon black, titanium dioxide, and, mixture thereof.

9: The process for producing (rigid) particle foams according to claim 1, wherein a pelletized material obtained after b) is discharged and supplied to a drying process.

10: The process for producing (rigid) particle foams according to claim 2, wherein a pelletized material obtained after c) is discharged and supplied to a drying process.

11: A method, comprising: installing the (rigid) particle foams produced by the process according to claim 1 in an aircraft, ship, or vehicle.

12: The process for producing (rigid) particle foams according to claim 3, wherein the at least one polymer having a glass transition temperature according to ISO 11357-2 of at least 180° C. is selected from the group consisting of polyethersulfone (PESU), polyphenylsulfone (PPSU), polysulfone (PSU), polyetherimide (PEI), a thermoplastic polyimide, and a mixture thereof.

13: The method according to claim 11, wherein the vehicle is an electromobility vehicle.

Description

EXAMPLES

Example 1

Underwater Pelletization of Ultem 1000 Type Polyetherimide.

[0050] Polyetherimide (PEI) (Ultem 1000, SABIC, the Netherlands), having a glass transition temperature of 217° C., measured according to ISO 11357-2 (published: 2014-07), is loaded into a reservoir vessel of an extruder (automatic single screw APM E1-180). The extrusion takes place at approx. 370-375° C. and a pressure of 15 bar. The throughput is 160 kg/h. The melt is supplied to an underwater pelletization system (Sphero 70, MAAG Automatlk GmbH, Germany) via a perforated plate. The pressure in the nozzle upstream of the perforated plate is approx. 195 bar. The pelletization is carried out with 9 knives at 2000 1/min.

[0051] The underwater pelletization takes place in two process water circuits. In a first, high-temperature circuit, the process water temperature is approx. 140° C. at a pressure of approx. 4.95 bar. In the second circuit, the process water temperature is approx. 70° C. at a pressure of approx. 2.5 bar. The residence time in the two circuits is in each case approx. 8 s.

[0052] The pelletized material is then dried in a centrifugal dryer (Centro 300, MAAG Automatik GmbH, Germany). The residual moisture content is 0.30% to 0.47%.