Preparation of low-dust stabilizers

US6225375A · kind A · utility

Assignee

• Ciba Specialty Chemicals Corporation · US

Inventors

• Daniel Thibaut · Michelbach-le-Bas, FR
• Andre Schmitter · Hégenheim, FR
• Benjamin Breitenstein · Rheinfelden, CH
• Christoph Kleiner · Aarau, CH
• Matthias von Frieling · Weil am Rhein, DE
• Martin Von Büren · Muttenz, CH
• Andre Geoffroy · Habsheim, FR

Key dates

• Filing date: Apr 13, 1998
• Grant date: May 1, 2001
• Expiry date: Apr 13, 2018

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C323/20
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A description is given of an extrusion process for the preparation of a low-dust stabilizer, using a subcooled melt as granulation liquid, as well as of novel amorphous modifications of different stabilizers, including 2,2'-methylenebis(4-[1,1,3,3-tetramethylbutyl]-6-benzotriazol-2-yl-phenol) , and of the .beta.-crystalline modification of 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole and of the preparation thereof. The novel process affords products which are easy to handle and which are flowable, and the novel modifications have advantages as regards their preparation, processing and their use as stabilizer.