Process for the production of polymethacrylimide foam materials

US5928459A · kind A · utility

Assignee

• Roehm GmbH Chemische Fabrik · DE

Inventors

• Werner Geyer · Heilbad Heiligenstadt, DE
• Hermann Seibert · Kaiserslautern, DE
• Sabine Servaty · Großlittgen, DE

Key dates

• Filing date: Apr 27, 1998
• Grant date: Jul 27, 1999
• Expiry date: Apr 27, 2018

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08J2333/24
• WIPO field: Other special machines
• WIPO sector: Mechanical engineering

Abstract

Polymethacrylimide foams are prepared by a method, comprising: preparing a mixture consisting of PA1 (a) a monomer mixture of 40-60 wt. % methacrylonitrile, 60-40 wt. % methacrylic acid, and, optionally, up to 20 wt. %, based on the sum of methacrylic acid and methacrylonitrile, of other monofunctional, vinyl-unsaturated monomers, PA1 (b) 0.5-8 wt. % of a propellant mixture of formamide or monomethyl formamide and a univalent C.sub.3-8 -aliphatic alcohol, PA1 (c) a cross-linking agent system, which consists of PA2 (c.1) 0.005-5 wt. % of a vinyl-unsaturated compound which can be radically polymerized, with at least two double bonds in the molecule, and PA2 (c.2) 1-5 wt. % magnesium oxide, dissolved in the monomer mixture, and at least one radical initiators and optionally at least one additive, shaped in the form of a sheet; polymerizing the monomers in the sheet; subsequently foaming the polymerizate sheet at temperatures from 200-260.degree. C.; and then heat treating the sheet in two steps, at a first step of 2-6 hours at 100-130.degree. C. and a second step of 32-64 hours at 180-220.degree. C.