Compounding crystalline organic materials

US4769200A · kind A · utility

Assignee

• BASF SE

Inventors

• Leopold Hupfer · Friedelsheim, DE
• Juergen Paetsch · Monsheim, DE
• Johann Hotz · Schifferstadt, DE
• Heino Thiele · Ludwigshafen, DE
• Hans D. Zettler · Havelsee, DE

Key dates

• Filing date: Jun 20, 1986
• Grant date: Sep 6, 1988
• Expiry date: Jun 20, 2006

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B01J2/20
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

In order to compound organic materials which are crystalline under standard conditions, these materials, in the pulverulent and/or molten state, are processed in a self-purging, twin-screw extruder in which the screws rotate in the same direction, ejected through one or more narrow passages into a low pressure zone, cooled and comminuted to give particles. In order to improve the pourability and shelf life, the materials are completely crystallized by the time they reach the end of the screws, and are heated during discharge through the narrow passage, in order to form a melt film. Dust-free granules havig a smooth surface can be produced in this manner.