HIGHLY FUNCTIONAL THIN POLARIZING FILM AND PROCESS FOR PRODUCING SAME

摘要

[Objects] To obtain a thin high-performance polarizing film having optical properties of a single layer transmittance of 42.0% or higher and a polarization rate of 99.95% or higher. [Means for accomplishing the Objects] A method for manufacturing a thin high-performance polarizing film having a thickness of 7µm or less and comprising a polyvinyl alcohol type resin having a dichroic material impregnated therein in a molecularly oriented state, therein the thin high-performance polarizing film has optical properties of a single layer transmittance of 42.0% or higher and a polarization rate of 99.95% or higher, the method comprising steps of coating a polyvinyl alcohol type resin on a resin substrate having a thickness of at least 20µm and then drying the resin to thereby form a polyvinyl alcohol type resin layer, immersing thus produced polyvinyl alcohol type resin layer in a dyeing solution including a dichroic material to thereby have the dichroic material impregnated in the polyvinyl alcohol type resin layer, stretching the polyvinyl alcohol type resin layer having the dichroic material impregnated therein together with the resin substrate in a boric acid solution such that a total stretching ratio of 5.0 or more of the original length is achieved.