material for forming transparent, resilient based on acrylates, and shaped articles obtained with this material and process for its preparation

摘要

A clear viscous moulding composition which neither becomes cloudy nor discolours under the effect of heat and moisture or when exposed to the weather, is made up of: A) 10 to 90% of a cohesive hard phase synthesised mainly from methylmethacrylate, with a glass transition temperature of above 70 DEG C and B) 90 to 10% of a viscous phase distributed in the hard phase and partly bonded thereto, with a glass transition temperature of less than -10 DEG C, an average particle size for the viscous phase of less than 130 nm and a non- uniformity of the viscous phase particle size of less than 0.5, synthesized from at least 50% (based on B) of a lower alkyl acrylate 0.5 to 5% of a graft cross linker or an at least trifunctional cross linker, C) not more than 0.05% of water-soluble constituents. A process for preparing the moulding composition comprises the emulsion polymerisation of A (to obtain a hard phase) in the presence of the viscous phase B dispersed in water, at least 15 wt. % of the hard phase being grafted on to the viscous phase.