Process for producing molded articles

Claim 1

A process for producing molded containers comprising the steps of: (a) passing, under non-lubrication rolling conditions, a crystalline polyolefin resin melt in sheet form at 220° to 250° C. through between rolls each having a surface roughness of not higher than 1S, as determined according to JIS B0601-55, and a surface temperature of not higher than 50° C. while simultaneously contacting both faces of the resin melt in sheet form with the rolls respectively, followed by still contacting at least one of the faces of the sheet with the roll or other rolls having the same surface roughness, to solidify the resin melt in sheet form thereby obtaining a sheet having a surface roughness of not higher than 0.7μ RMS on each face, (b) further passing, under non-lubrication rolling conditions, the thus obtained sheet through between at least one pair of rolls having a surface roughness of not more than 0.8S and rotating in the direction opposite to each other and having therebetween a clearance smaller than the thickness of the sheet while maintaining the sheet at lower than the crystalline melting point thereof, to roll the sheet in a rolling ratio of 1.1-2.0 thereby obtaining a rolled, oriented sheet and then (c) forming the thus obtained rolled sheet under pressure while maintaining the rolled sheet at lower than the crystalline melting point thereof by not more than 40° C., thereby to obtain the molded articles.