Polarizer films comprising wholly aromatic liquid crystalline polymers and dichroic dyes
AssigneeHoechst Celanese Corporation
InventorsSunny S. Shen, Hyun Nam Yoon, Mohammad Mortazavi
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Abstract
This invention provides novel liquid crystalline polymers which, when mixed with a suitable dye and extruded, yields polarizer films with superior polarizing efficiency, transmittance, dichroic ratio, and thermal and humidity stability. The invention further provides a process to prepare such polymers and polarizer films therefrom.
Claims22
A polarizing film having a polarizing efficiency of at least 70% and comprising a blend of a film-forming, wholly aromatic thermotropic liquid crystal polymer and a dichroic dye, with said liquid crystal polymer being a polyester which comprises repeat units corresponding to the formula:
- -P.sup.1 !.sub.m -P.sup.2 !.sub.n -P.sup.3 !.sub.q -
- wherein P.sup.1, P.sup.2, and P.sup.3 represent monomeric moieties with P.sup.1 being an aromatic hydroxy carboxylic acid, P.sup.2 being an aromatic dicarboxylic acid, and P.sup.3 being a phenol, with m, n and q representing mole percent of the respective monomers ranging from 5-70 mole percent individually.
A polarizing film having a polarizing efficiency of at least 70% and comprising a blend of (a) a film-forming wholly aromatic thermotropic liquid crystal polyester which comprises 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, terephthalic acid, 4,4'-dihydroxybiphenyl and resorcinol in a molar ratio 30:30:20:10:10 respectively, and (b) a dichroic dye.
A process of preparing a polarizer film-forming composition, which process comprises:
- (a) preparing a suitable film-forming, wholly aromatic thermotropic liquid crystal polymer and (b) blending said liquid crystal polymer with one or more suitable dichroic dyes by a suitable process to form the polarizer film-forming composition, with said liquid crystal polymer being a polyester or a polyesteramide, wherein said polyester comprises repeat units corresponding to the formula:
- -P.sup.1 !.sub.m -P.sup.2 !.sub.n -P.sup.3 !.sub.q -
- wherein P.sup.1, P.sup.2, and P.sup.3 represent monomeric moieties with P.sup.1 being an aromatic hydroxy carboxylic acid, P.sup.2 being an aromatic dicarboxylic acid, and P.sup.3 being a phenol;
- and further wherein said polyesteramide comprises repeat units corresponding to the formula:
- -P.sup.4 !.sub.m -P.sup.5 !.sub.n -P.sup.6 !.sub.q -
- wherein P.sup.4, P.sup.5, and P.sup.6 represent monomeric moieties with P.sup.4 being an aromatic amino carboxylic acid, P.sup.5 being an aromatic dicarboxylic acid, and P.sup.6 being a phenol;
- with m, n and q representing mole percent of the respective monomers ranging from 5-70 mole percent individually.
A polarizing film having a polarizing efficiency of at least 70% and comprising a blend of a film-forming, wholly aromatic thermotropic liquid crystal polymer and a dichroic dye, with said liquid crystal polymer being a polyesteramide which comprises repeat units corresponding to the formula:
- -P.sup.1 !.sub.m -P.sup.2 !.sub.n -P.sup.3 !.sub.q -
- wherein P.sup.1, P.sup.2, and P.sup.3 represent monomeric moieties with P.sup.1 being an aromatic amino carboxylic acid, P.sup.2 being an aromatic dicarboxylic acid, and P.sup.3 being a phenol with m, n and q representing mole percent of the respective monomers ranging from 5-70 mole percent individually.
Dependencies are inferred from the claim text.