POLYESTER CONTAINER AND PREPARATION THEREOF

摘要

PURPOSE:To obtain a container having excellent heat resistance and good adhesiveness to the cap by making the surface roughness of the heat-adhered part in a specified state and by making the degree of crystallinity of the bottom and the side of the container higher than a specified value. CONSTITUTION:A container is obtained by heat molding a polyester sheet consisting mainly of polyethylene terephthalate. The surface roughness of the part of the container to be heat-adhered with a cap is roughened to the state corresponding to Rmax>=10mum of the planar cut processing and the degree of crystallinity of the bottom and the side of the container is higher than 20%. The container is prepared by heating and softening the polyester sheet and heat molding it in a mold being kept in the temp. range of crystallization of the polyester. In this processing, a part for pressing or a mold being roughened to the state corresponding to Rmax>=15mum of the planar cut processing is brought in contact under pressure with the part of the container to be heat- adhered with the cap. If the surface roughness of the part for pressing or the mold is smaller than 15mum of Rmax, the surface roughness of the surface of the container to be heat-adhered with the cup becomes smaller than 10mum of Rmax and the heat adhesiveness with the cup decreases.