Polyvinyl alcohol-based film for optical use, polarizing film, and polarizing plate

Abstract

The present invention provides a polyvinyl alcohol-based film for optical uses, which is excellent in stretching property and is used for producing a polarizing film excellent in polarization performance throughout the visible light wavelength range, particularly in the vicinity of the wavelength of 460 nm. The invention relates to a polyvinyl alcohol-based film for optical uses comprising a polyvinyl alcohol-based resin, wherein the polyvinyl alcohol-based resin is composed of only a polyvinyl alcohol-based resin (A) containing a 1,2-glycol bond at a side chain and the amount of the 1,2-glycol bond at a side chain is from 0.01 to 6% by mol, or a polyvinyl alcohol-based film for optical uses comprising a polyvinyl alcohol-based resin, wherein the polyvinyl alcohol-based resin includes a polyvinyl alcohol-based resin (A) containing a 1,2-glycol bond at a side chain and a polyvinyl alcohol-based resin (B) other than the polyvinyl alcohol-based resin (A) and satisfies the following expression (1): 0.01≦A×G/(A+B)≦6  (1) wherein A represents a content ratio (weight ratio) of the polyvinyl alcohol-based resin (A) based on a total amount of the polyvinyl alcohol-based resin (A) and the polyvinyl alcohol-based resin (B), B represents a content ratio (weight ratio) of the polyvinyl alcohol-based resin (B) based on the above total amount, and G represents an amount (% by mol) of the 1,2-glycol bond at a side chain.

Dependencies are inferred from the claim text.