Roehm Gmbh & Co Kg

Roehm Gmbh Chemische Fabrik

Ernst Mohr

Michael Wicker

Heinz Vetter

Klaus Albrecht

Uwe Numrich

Thomas Rhein

Mona Rueppel

Hermann Jaksch

Gerald Dietrich

Products based on polymethylmethacrylate (PMMA) so resistant to yellowing and so highly transparent that even the edges of plates produced from this material have a neutral colour, i.e. do not display any yellow tone. This effect is obtained by the admixture of 5 to 50 ppm inorganic, reducing phosphorus compounds after polymerisation. This enables the brightener content to be reduced under 10 ppb, and so the end product may also be used in contact with foodstuffs.

Process for producing polymethylmethacrylate molding materials with a neutral color

A thermoplastic polymethacrylate molding material with a high degree of thermal dimensional stability, a high degree of transparency, a high degree of flowability and a high degree of resistance against water, monomeric methylmethacrylate, mixtures consisting of ethanol and water, as well as fuel, wherein the molding material is a compatible mixture of 1 to 99 wt % of a copolymer P, made from (p1) 30 to 70 wt % styrene and/or .alpha.-methylstyrene, (p2) 29 to 70 wt % (C.sub.1 -C.sub.6 -alkyl)methacrylate, and (p3) 1 to 20 wt % acrylic acid and/or methacrylic acid, the sum of (p1), (p2), and (p3) adding up to 100 wt %, and 99 to 1 wt.-parts of a polymethylmethacrylate polymer PM, made of (pm1) 80 to 100 wt % methylmethacrylate, as well as (pm2) 0 to 20 wt % monomers which can be copolymerized with methylmethacrylate.

Thermoplastic molding materials having high transparency prepared from

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Lorsch, Germany

Ernst Mohr