This standard applies to raw-secondary materials as defined in UNI 10667-1, obtained from the recycling of industrial residues and / or materials from pre and / or post-consumer styrene-based plastics, defines the requirements and test methods of mixtures of "crystal" homopolymer polystyrene (R PS), shock-resistant polystyrene mixtures (R PS-HI) and homopolymer and shock-resistant polystyrene mixtures (R PS-MIX), intended for different uses, to be used alone or mixed with others materials.