Laminated metal sheet for can lid excelling in appearance after retorting

摘要

The laminated metal sheet for can end is formed by laminating polyester film on both sides thereof, thus providing excellent appearance after retorting. The polyester film laminated to a side to become outer face of the formed can end has (1) half-time of crystallization of the resin of amorphous polyester layer formed near the interface between the polyester film and the metal sheet of 40 seconds or smaller at 130° C., (2) thickness of the amorphous polyester layer from 0.5 to 8 mum, (3) water vapor transmissivity of the polyester film of 100 g/m²/24 hr or smaller. The amorphous polyester layer resin is preferably a polyester composition prepared by formulating a polyester (I) (30 to 60% by weight) composed mainly of ethylene terephthalate as the main repeating unit, and a polyester (II) (40 to 70% by weight) composed mainly of butylene terephthalate as the main repeating unit.