PRESSURE-SENSITIVE ADHESIVE TYPE POLARIZER WITH RETARDATION LAYER, PROCESS FOR PRODUCING THE SAME, OPTICAL FILM, AND IMAGE DISPLAY

摘要

A pressure-sensitive adhesive type retardation-layer-possessing polarizer (4) obtained by forming a polarizer (2) comprising an iodine-containing polarizing element (1) and transparent protective films superposed respectively on both sides thereof, disposing a retardation layer on at least one of the transparent protective films of the polarizer (2) to produce a retardation-layer-possessing polarizer (3), and further superposing a pressure-sensitive acrylic adhesive layer on the retardation layer side. In the iodine-containing polarizing element (1), the ratio of the content of potassium (K) (wt.%) to the content of iodine (I) (wt.%), (K/I), is 0.200-0.235. In the polarizer (2), the iodine-containing polarizing element (1) has been laminated to the transparent protective films through an adhesive layer formed from a water-soluble adhesive comprising a polyvinyl alcohol resin having acetoacetyl groups and a crosslinking agent. The retardation-layer-possessing polarizer (3) has a degree of shrinkage in the absorption axis direction, as measured after 24-hour standing at 80°C and expressed by the following equation, of 0.5% or lower. The pressure-sensitive adhesive type retardation-layer-possessing polarizer (4) by itself has a transmittance of 41.0-43.2%. This pressure-sensitive adhesive type retardation-layer-possessing polarizer can be inhibited from changing in optical properties even under high-temperature high-humidity conditions and can keep visibility high.