OPTICAL FILM AND POLARIZING PLATE USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide an optical film excellent in moisture permeability even though it is a thin film, improving moist heat resistance of a polarizing element when used for polarizing plate protection films and, at the same time, excellent in mass change of the film after moist heat conditions and excellent in front face contrast by suppressing disturbance of the molecular orientation of an additive and cellulose even when extended in a high magnifying power, and a polarizing plate using the same.

SOLUTION: The optical film having a tan δ in the width direction of the film, which has in the following relation, is provided: 0.50≥tan δ-40/tan δpeak≥0.22, wherein the tan δpeakmeans the maximum value of tan δ measured at 25-210°C, and the tan δ-40means the value of a tan δ measured at [(the temperature when the tan δpeakis expressed)-40°C].

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