Commission Regulation (EEC) No 1794/77 of 2 August 1977 re-establishing the levying of the customs duties on acrylic polymers, methacrylic polymers and acrylo-methacrylic copolymers, in the form of plates, sheets, etc., falling within subheading 39.02 C ex XII, originating in Thailand to which the preferential tariff arrangements set out in Council Regulation (EEC) No 3021/76 apply