Abstract: A method which includes enhancing effects upon treating the surface of a thermoplastic resin article by a surface-activating treatment such as corona discharge and the like or by a primer treatment and, thereby, improving coating performance, printability, adhesiveness and so forth of the thermoplastic resin article. The resin article is subjected to a surface-heating treatment which comprises heating only surface layer of the resin article up to a melting point of the thermoplastic resin or a higher temperature followed by cooling the surface layer, and then, subjected to the surface-activating treatment or primer coating.

Abstract: In a method of corona discharge processing of resin formings surface, excellent corona discharge processing is possible, even if there is a distance between the resin formings and the discharge electrode, by generating a high voltage pulse having a pulse width of 1 .mu.s or more, an average electric field strength of 4 to 20 kv/cm denoted by applied voltage (wave height) versus interelectrode distance, and a pulse frequency of 10 pps or more. This processing is performed by the apparatus which comprises arranging a transfer conveyor to transfer the resin formings, a counter-electrode placed in a down side of the transfer conveyor, a dielectric to cover a surface of the counter-electrode, and a number of discharge electrodes which are arranged in a definite distance above the resin formings along the transfer route.