Retardation film, composition, method of manufacturing retardation film, polarizing plate and liquid crystal display device

Abstract

An object of the present invention is to provide a film capable of giving a necessary retardation without degrading the contrast. The present invention provides a retardation film formed from a composition which includes a polymer compound, a rod-like liquid crystal compound and a photo-reactive compound, wherein the polymer compound has a side chain which has one or more azo groups and/or cynnamate groups, and 3 or more and 10 or less arylene groups; the side chain further has an optionally substituted amino group, or a hydrocarbon group at the terminal; an absolute value of difference between an SP value of the polymer compound and an SP value of the photo-reactive compound is 1.1 or less; and an in-plane retardation of the film at wavelength of 550 nm is 10 nm or more and 200 nm or less.

1 . A retardation film comprising a polymer compound and an alignment controlling agent, wherein the polymer compound has a side chain which has one or more azo groups and/or cynnamate groups and 3 or more and 10 or less of arylene group, the side chain further has an optionally substituted amino group, or a hydrocarbon group at the terminal, a content of the polymer compound in the retardation film is 71% by mass or more, and an in-plane retardation of the film at wavelength of 550 nm is 10 nm or more and 200 nm or less. 
     
     
         2 . The retardation film of  claim 1 , wherein the polymer compound is a compound represented by Formula IX: 
       
         
           
           
               
               
           
         
         in the formula, R 1  represents a hydrogen atom or methyl group, L represents a single bond, —(CH 2 ) x O— or —(CH 2 CH 2 O) y —, x is an integer of 2 to 10, y is an integer of 1 to 5, R 2  represents an optionally substituted amino group or hydrocarbon group, and M represents a structure represented by Formula X below: 
       
       
         
           
           
               
               
           
         
         in the formula, each * represents a bonding site with L or R 2 ; Y represents an azo group, —OCO—, —CO(═O)—, —OCO—CH═CH— or —CH═CH—CO 2 —, m represents an integer of 2 to 9, the plurality of (Y)s may be same or different; and Ar represents an optionally substituted arylene group. 
       
     
     
         3 . The retardation film of  claim 1 , wherein the alignment controlling agent is a compound represented by Formula I below: 
       
         
           
           
               
               
           
         
         in the formula, each R 201  independently represents an aromatic hydrocarbon ring or heterocycle having substituent(s) at least on any of the ortho, meta and para positions, each X 201  independently represents a single bond or —NR 202 —, each R 202  independently represents a hydrogen atom, or alkyl group, alkenyl group, aromatic hydrocarbon cyclic group or heterocyclic group, which may be substituted or unsubstituted. 
       
     
     
         4 . The retardation film of  claim 1 , wherein a content of the alignment controlling agent, relative to 100 parts by mass of the polymer compound, is 0.1 to 20 parts by mass. 
     
     
         5 . The retardation film of  claim 1 , which is a single layered film. 
     
     
         6 . The retardation film of  claim 1 , which has an Nz value of −0.29 to 0.29;
 where, Nz=(nx−nz)/(nx−ny), nx represents refractive index in in-plane slow axis direction, ny represents refractive index in an in-plane direction normal to nx, and nz represents refractive index normal to nx and ny. 
 
     
     
         7 . The retardation film of  claim 1 , which has a thickness of 5 μm or less. 
     
     
         8 . A composition comprising a polymer compound and an alignment controlling agent, wherein the polymer compound has a side chain which has one or more azo groups and/or cynnamate groups, and 3 or more and 10 or less arylene groups; the side chain further has an optionally substituted amino group, or a hydrocarbon group at the terminal; and a content of the polymer compound in the composition is 71% by mass or more relative to the total solid content. 
     
     
         9 . A method of manufacturing a retardation film of  claim 1 , which comprises coating the composition of  claim 8  over a substrate. 
     
     
         10 . The method of manufacturing a retardation film according to  claim 9 , which further comprises heating the composition, having been coated on the substrate, at 40° C. or above, and photo-irradiating the composition after heating at a dose of 300 to 30000 mJ/cm 2 . 
     
     
         11 . A polarizing plate comprising a polarizer, and the retardation film of  claim 1 . 
     
     
         12 . A liquid crystal display device comprising the retardation film of  claim 1 . 
     
     
         13 . The liquid crystal display device of  claim 12 , which is an IPS liquid crystal display device.