MANUFACTURE OF PARTIALLY POLARIZING FILM

摘要

PURPOSE:To obtain a partially polarizing film having a sufficient nonpolarizing part by forming a mixture of a decoloring agent with a specified substance on one side of a polarizing film having a support formed on the other side and treating the film at high temp. and humidity. CONSTITUTION:An aqueous sonl. contg. a mixture consisting of a decoloring agent such as NaOH and a water-soluble or water-swellable substance in which the decoloring agent can be diffused and moved, e.g. starch in (1-4):(9-6) weight ratio is partially applied to a prescribed region of one side of a polarizing film such as a polyvinyl alcohol film having a support of 25-500mum thickness such as a polyester film stuck to the other side so as to adjust the solid matter content to 0.1-20g/m<2>. The polarizing film is then treated at 40-95 deg.C high temp. and 70-98% high relative humidity for 1-60min to oxidize or reduce iodine molecules in the applied part. The polarizing power of the part is lost.