PRODUCTION OF POLYPROPYLENE RESIN SHEET

摘要

PROBLEM TO BE SOLVED: To produce a polypropylene resin sheet having high rigidity and high transparency after annealing treatment. SOLUTION: Both end parts of a polypropylene resin sheet are grasped by the clips of a grasping mechanism and the resin sheet is indirectly heated by an infrared heater of a heater 27 in such a state that the central part thereof is slackened. At this time, the stretching in the TD direction of the resin sheet 11 is controlled so as to become 0-10%. The heating temp. of the resin sheet 11 is controlled to a temp. range from 100 deg.C to the m.p. of the resin sheet 11. This polypropylene resin sheet 11 to be subjected to annealing treatment is characterized by that density measured by a density gradient pipe method is 0.890g/cm<3> or less, the total haze is 5% or less and gloss is 120% or more.