| 摘要 |
A method for producing a foamed plastic sheet which comprises heating and kneading a thermoplastic synthetic resin composition containing a blowing agent in an extruder, extruding the resulting gel through a circular die provided at the end of the extruder, and pinching the tubular foamed extrudate with a pair of pinch rolls while it is still in the softened state to adhere the inside wall of the foamed tubing to itself, is characterized in that said pinching and adhesion are performed by using a pair of pinch rolls having a width at least 5% smaller than the width of the tubular foamed extrudate extruded in the flattened state so that non-adhered parts are formed at both side end portions of the pinched foamed sheet in the widthwise direction and the inside of the non-adhered parts communicates with the open air. |
