Evonik Rohm Gmbh

Evonik Roehm Gmbh

Nils Mehler

Klaus Schultes

Werner Hoess

Klaus Albrecht

Ursula Golchert

Thorsten Goldacker

Stefan Nau

Roger Recktenwald

Ernst Becker

Krzysztof Sado

Victor Khrenov

Sabine Schwarz-Barac

Werner Höss

Markus Schubert

Markus Vogt

Birgit Riedel-Bendzko

Joachim Henn

Daniel Cleff

Norbert Bendzko

Process for preparing molding materials MM with improved optical and color properties, consisting of a polymer PM which contains units of the formula I in which Rand Rare each hydrogen and methyl and Ris hydrogen, C-C-alkyl, C-C-cycloalkyl, C-C-aryl, C-C-aryl-C-C-alkyl, where these radicals may be up to trisubstituted by radicals selected from the group consisting of C-C-alkoxy and halogen, prepared in an imidation reaction known per se in a reactive extruder,in which, on completion of the imidation reaction, an amount of one or more reducing phosphorus compounds P which is effective for color stabilization is added to the polymer PM, characterized in that the phosphorus compounds are organic phosphorus compounds OP selected from the group consisting of compounds of the formula II in which Rand Rare each independently hydrogen or an aromatic 6-membered ring which may be up to pentasubstituted by a C-C-alkyl and/or C-C-cycloalkyl groups. Shaped bodies obtainable by the process, especially light waveguides, have a low tendency to yellowing under thermal stress, coupled with a low haze, and also a stable and high transparency.

Poly(meth)acrylimide having improved optical and color properties, particularly under thermal load

Provided is a molding composition comprising, based on the total weight of the composition, (A) 50.0% by weight to 99.5% by weight of at least one (co)polymer which is a homopolymer or copolymer of at least 80% by weight of methyl methacrylate, (B) 0.5% by weight to 50.0% by weight of at least one copolymer obtained by polymerization of a monomer, and (C) at least one low molecular weight (meth)acrylate (co)polymer having a solution viscosity in chloroform at 25&#xb0; C. (ISO 1628&#x2014;part 6) of less than or equal to 55 ml/g.

Composition with increased stress cracking resistance

Composition containing, based in each case on its total weight, The moldings obtainable from the composition are distinguished in particular by improved stress cracking resistance and are suitable in particular for coverings, finishes or films.

The invention relates to a composition containing, in relation to the total weight of said composition, A) between 50.0% by weight and 99.5% by weight of at least one (meth)acrylate (co)polymer and B) between 0.5% by weight and 50.0% by weight of at least one copolymer, obtained by the polymerization of a monomer mixture consisting of i. between 70% by weight and 92% by weight of a vinyl aromatic monomer and ii. between 8% by weight and 30% by weight of acryl nitrile or methacryl nitrile or mixtures thereof iii. between 0% by weight and 22% by weight of at least one other monomer, the composition having at 50&#xb0; C. a &#x394;E of less than 0.15, &#x394;E being defined according to the relationship (1): (1) in which &#x394;L*: the modification of the color co-ordinates L* compared with the color co-ordinates L* at 23&#xb0; C., &#x394;a*: the modification of the color co-ordinates a* compared with the color co-ordinates a* at 23&#xb0; C., &#x394;b*: the modification of the color co-ordinates b* compared to the color co-ordinates b* at 23&#xb0; C., and the composition contains at least one (meth)acrylate (co)polymer a) with a solution viscosity in chloroform at 25&#xb0; C. (ISO 1628 part 6) greater than 55 ml/g. The molded bodies that can be obtained from the composition are characterized in particular by improved stress cracking resistance and are suitable in particular for use in coatings, paints or films.

Coloured composition with increased stress cracking resistance

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Brensbach, Germany

Nils Mehler