Plastics - Acrylonitrile-Styrene-Acrylate (ASA)@ Acrylonitrile-(Ethylene-Propylene-Diene)-Styrene (AEPDS) and Acrylonitrile-(Chlorinated Polyethylene)-Styrene (ACS) Moulding and Extrusion Materials - Part 1: Designation Systems and Basis for Specification