scope:

This International Standard specifies a method of designation, and general requirements, for impact-resistant polystyrene moulding and extrusion materials; it is intended to be the basis for a full specification to be published later. The types of impact-resistant polystyrene moulding and extrusion materials are differentiated from one another by appropriate levels of selected specific properties. Impact-resistant polystyrene itself is described by general characteristics selected for reference purposes. These types are uncoloured or coloured materials comprising polymers of styrene (possibly epolymerized) with small amounts of an alkyldyrene) modified with butadiene based rubber to obtain greater toughness, indicated by values of impact strength exceeding that for normal polystyrene as designed by ISO 1622. Lubricants, softeners, antioxidants and other additives may be present but are not further specified here.