Polarizing film

Claim 1

A polarizing film comprising a hydrophobic polymer containing a dichroic organic colorant in an oriented state which is characterized in that the dichroic organic colorant, which is a compound of the formula: ##STR198## where Y represents an oxygen atom or a sulfur atom; X 7 , X 8 , X 9 , X 10 , X 11 , X 12 represent hydrogen atoms, halogen atom, hydroxyl groups or amino groups that may be substituted by an alkyl group of 1 to 3 carbon atoms; Q represents an anthraquinone radical that may be substituted by X 7 , X 8 , X 9 , X 10 , X 11 or X 12 , or a group of the formula: ##STR199## where R 1 and R 2 represent hydrogen atoms, halogen atoms, methyl groups or methoxy groups, m represents a whole number equal to 1, 2 or 3, and R 7 represents --COOH, --COOR 4 , --CONH 2 , --CONHR 4 , --COCR 4 , --NHCOR 4 , --N═N--R 4 , ##STR200## in which R 4 and ring B represent phenyl, biphenyl or naphthalene radicals that may be substituted by R 1 , R 2 , --COOH and/or --COOCH 3 , has a solubility in water, organic solvents and liquid crystals of not greater than 0.05 percent by weight at about 25° C., and the dichroic ratio of the colorant is not less than 7 when it is measured with the film obtained by blending the colorant intimately with polyethylene terephthlate, melting the resulting blend and forming it into a film.