Negative C-type compensation film and method of preparing the same

A method of preparing a negative C-type compensation film, the negative C-type compensation film comprising a base layer and a polymer layer comprising polyarylate, comprising:

• a) mixing the polyarylate, which comprises a repeating unit represented by formula (1) and is prepared by copolymerizing divalent phenols, divalent aromatic carboxylic acid halides, and 0.01 to 49.9 mol % of bisphenol derivatives of the formula (2), and an organic solvent to prepare a polyarylate solution;
• b) applying the polyarylate solution on a base substrate, and volatilizing a solvent to produce a cast film;
• and
• c) drying the case film to produce the negative C-type compensation film,
• wherein R1 to R8 are each independently hydrogen, alkyl having 1 to 12 carbon atoms, arylalkyl having 7 to 12 carbon atoms, aryl having 6 to 12 carbon atoms, nitrile, alkylenenitrile having 2 to 12 carbon atoms, alkoxy having 1 to 12 carbon atoms, acyl having 1 to 12 carbon atoms, alkenyl having 2 to 12 carbon atoms, alkylalkenyl having 3 to 12 carbon atoms, arylalkenyl having 8 to 12 carbon atoms or halogen, in which the alkenyl of the above substituent(s) may be introduced with at least one functional group of an epoxide group, an alkoxy group, a hydroxy group and an amine group, provided that at least one of R1 to R4 or at least one of R5 to R8 is alkenyl having 2 to 12 carbon atoms, alkylalkenyl having 3 to 12 carbon atoms or arylalkenyl having 8 to 12 carbon atoms, in which the alkenyl of the above substituent(s) may be introduced with at least one functional group of an epoxide group, an alkoxy group, a hydroxy group and an amine group;
• W and W′ are each independently directly bonded, or are each independently oxygen, sulfur, sulfoxide, sulfone, alkylidene having 1 to 30 carbon atoms, alkylene having 2 to 30 carbon atoms, cycloalkylidene having 3 to 30 carbon atoms, cycloalkylene having 3 to 30 carbon atoms or phenyl-substituted alkylene having 2 to 30 carbon atoms;
• and
• —OOCYCOO— and —OOCY′COO— are each independently terephthalic acid, isophthalic acid, dibenzoic acid or naphthalene dicarboxylic acid, in which the aromatic group may be substituted with a substituent selected from the group consisting of alkyl having 1 to 8 carbon atoms, aryl, alkylaryl and halogen, and
• wherein R9 to R12 are each independently hydrogen, alkyl having 1 to 12 carbon atoms, arylalkyl having 7 to 12 carbon atoms, aryl having 6 to 12 carbon atoms, nitrile, alkylenenitrile having 2 to 12 carbon atoms, alkoxy having 1 to 12 carbon atoms, acyl having 1 to 12 carbon atoms, alkenyl having 2 to 12 carbon atoms, alkylalkenyl having 3 to 12 carbon atoms, arylalkenyl having 8 to 12 carbon atoms or halogen, provided that at least one of R9 to R12 is alkenyl having 2 to 12 carbon atoms, alkylalkenyl having 3 to 12 carbon atoms or arylalkenyl having 8 to 12 carbon atoms;
• and
• W is directly bonded, or is oxygen, sulfur, sulfoxide, sulfone, alkylidene having 1 to 30 carbon atoms, alkylene having 2 to 30 carbon atoms, cycloalkylidene having 3 to 30 carbon atoms, cycloalkylene having 3 to 30 carbon atoms or phenyl-substituted alkylene having 2 to 30 carbon atoms.

A liquid crystal display having the negative C-type compensation film comprising:

• a) a base layer;
• and
• b) a polymer layer comprising polyarylate which comprises a repeating unit represented by the formula (1) and prepared by copolymerizing divalent phenols, divalent aromatic carboxylic acid halides, and 0.01 to 49.9 mol % of bisphenol derivatives of the formula (2), the base layer and the polymer layer being sequentially layered,
• wherein R1 to R8 are each independently hydrogen, alkyl having 1 to 12 carbon atoms, arylalkyl having 7 to 12 carbon atoms, aryl having 6 to 12 carbon atoms, nitrile, alkylenenitrile having 2 to 12 carbon atoms, alkoxy having 1 to 12 carbon atoms, acyl having 1 to 12 carbon atoms, alkenyl having 2 to 12 carbon atoms, alkylalkenyl having 3 to 12 carbon atoms, arylalkenyl having 8 to 12 carbon atoms or halogen, in which the alkenyl of the above substituent(s) may be introduced with at least one functional group of an epoxide group, an alkoxy group, a hydroxy group and an amine group, provided that at least one of R1 to R4 or at least one of R5 to R8 is alkenyl having 2 to 12 carbon atoms, alkylalkenyl having 3 to 12 carbon atoms or arylalkenyl having 8 to 12 carbon atoms, in which the alkenyl of the above substituent(s) may be introduced with at least one functional group of an epoxide group, an alkoxy group, a hydroxy group and an amine group;
• W and W′ are each independently directly bonded, or are each independently oxygen, sulfur, sulfoxide, sulfone, alkylidene having 1 to 30 carbon atoms, alkylene having 2 to 30 carbon atoms, cycloalkylidene having 3 to 30 carbon atoms, cycloalkylene having 3 to 30 carbon atoms or phenyl-substituted alkylene having 2 to 30 carbon atoms;
• and
• —OOCYCOO— and —OOCY′COO— are each independently terephthalic acid, isophthalic acid, dibenzoic acid or naphthalene dicarboxylic acid, in which the aromatic group may be substituted with a substituent selected from the group consisting of alkyl having 1 to 8 carbon atoms, aryl, alkylaryl and halogen, and
• wherein R9 to R12 are each independently hydrogen, alkyl having 1 to 12 carbon atoms, arylalkyl having 7 to 12 carbon atoms, aryl having 6 to 12 carbon atoms, nitrile, alkylenenitrile having 2 to 12 carbon atoms, alkoxy having 1 to 12 carbon atoms, acyl having 1 to 12 carbon atoms, alkenyl having 2 to 12 carbon atoms, alkylalkenyl having 3 to 12 carbon atoms, arylalkenyl having 8 to 12 carbon atoms or halogen, provided that at least one of R9 to R12 is alkenyl having 2 to 12 carbon atoms, alkylalkenyl having 3 to 12 carbon atoms or arylalkenyl having 8 to 12 carbon atoms;
• and
• W is directly bonded, or is oxygen, sulfur, sulfoxide, sulfone, alkylidene having 1 to 30 carbon atoms, alkylene having 2 to 30 carbon atoms, cycloalkylidene having 3 to 30 carbon atoms, cycloalkylene having 3 to 30 carbon atoms or phenyl-substituted alkylene having 2 to 30 carbon atoms.