The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 10, 1998
Filed:
Nov. 27, 1996
Uwe Numrich, Weiterstadt, DE;
Michael Wicker, Seeheim-Jugenheim, DE;
Thomas Rhein, Stadecken-Elsheim, DE;
Thomas Suefke, Erzhausen, DE;
Roehm GmbH Chemische Fabrik, Darmstadt, DE;
Abstract
Highly transparent, impact-resistant molding compositions based on polymethyl methacrylate (PMMA), having excellent color stability both during processing at high temperatures, as well as when under thermal stress, as a result of multiple processing with simultaneously high weathering stability and stability of the optical characteristics with the effect of water. Preparation is carried out according to a multi-step extruder process, wherein an extruder for the melt coagulation and one for the compounding are connected in series. Addition of small quantities of reducing inorganic phosphorous compounds at a later stage provides prolonged effectiveness.