Method and apparatus for surface-hardening treatment of synthetic resin shaped articles

摘要

Method and apparatus for the surface-hardening treatment of a synthetic resin shaped article is provided, wherein the shaped article is dipped in a surface-hardening solution; the shaped article is gradually pulled up therefrom thereby to be coated with the surface-hardening solution; and the coated article is irradiated with ultraviolet rays to cure the coating. The shaped article is dipped in succession in a washing tank, a drying tank having warm water or an organic solvent and a hardening solution tank while the shaped article is conveyed by a first conveyor, and then, the shaped article is transferred from the first conveyor through an intermediate conveyor to a second conveyor whereby the shaped article is conveyed to an ultraviolet ray-curing step. The shaped article is introduced to and withdrawn from the respective steps in the state where the shaped article is hung on a hanger, and one or a plurality of hangers are attached to each of a plurality of portions of the first conveyor so that the shaped articles are simultaneously subjected to the dipping treatment in the respective tanks, whereas the hangers are conveyed one by one from the intermediate conveyor to the second conveyor where the shaped articles are separately hung. In each of the tanks, organic solvent and the hardening solution tank, the liquid is overflowed therefrom and circulated via a filter to each tank. The surface-hardening treatment is carried out under such conditions that the hardening solution and the atmosphere above the hardening solution tank are maintained at room temperature and the dew point of said atmosphere is maintained at least 3 DEG C. lower than the temperature of the hardening solution.