Adhesive composition for polarizing plate, polarizing plate using same, preparation method therefor, and optical member comprising same

Abstract

Disclosed are an adhesive composition for polarizing plates, a polarizing plate using the same, a method for preparing the same, and an optical member including the same. The adhesive composition includes (A) a (meth)acrylic radical compound, (B) a cationic epoxy compound, (C) a phenoxy resin, and (D) a photoinitiator.

1 . An adhesive composition for a polarizing plate, the adhesive composition comprising:
 (A) a (meth)acrylate compound,   (B) a cationic epoxy compound,   (C) a phenoxy resin, and   (D) a photoinitiator.   
     
     
         2 . The adhesive composition according to  claim 1 , wherein the (C) phenoxy resin is present in an amount of about 0.1 parts by weight to about 5 parts by weight, based on 100 parts by weight of (A)+(B)+(C). 
     
     
         3 . The adhesive composition according to  claim 1 , wherein the adhesive composition is a solvent-free adhesive composition. 
     
     
         4 . The adhesive composition according to  claim 1 , wherein a weight ratio of the (A) (meth)acrylate compound: the (B) cationic epoxy compound ranges from about 10:90 to about 50:50. 
     
     
         5 . The adhesive composition according to  claim 1 , wherein the (C) phenoxy resin includes a non-curable phenoxy resin. 
     
     
         6 . The adhesive composition according to  claim 1 , wherein the (C) phenoxy resin includes a resin compound represented by Formula 1: 
       
         
           
           
               
               
           
         
         wherein, 
         R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7  and R 8  are each independently hydrogen, a halogen, a C 1 -C 10  alkyl group, a C 6 -C 20  aryl group, a C 5 -C 20  cycloalkyl group, or a nitro group; 
         R 9 , R 10 , R 11 , R 12 , R 13  and R 14  are each independently hydrogen or a hydroxyl group, at least one of R 9 , R 10 , R 11 , R 12 , R 13  and R 14  being a hydroxyl group; 
         X 1  is a single bond or a linear or branched C 1 -C 5  alkylene group; 
         Z is a hydroxyl group or an epoxy group; and 
         n is an integer from 30 to 400. 
       
     
     
         7 . The adhesive composition according to  claim 1 , wherein the (A) (meth)acrylate compound includes a C 1 -C 20  alkyl group that has at least one hydrophilic group. 
     
     
         8 . The adhesive composition according to  claim 1 , wherein the (B) cationic epoxy compound includes an alicyclic epoxy compound, an aromatic epoxy compound, an aliphatic epoxy compound, a hydrogenated epoxy compound, or mixtures thereof. 
     
     
         9 . The adhesive composition according to  claim 1 , wherein the adhesive composition includes:
 about 1 part by weight to about 86 parts by weight of the (A) (meth)acrylate compound,   about 10 parts by weight to about 95 parts by weight of the (B)cationic epoxy compound,   about 0.1 parts by weight to about 5 parts by weight of the (C)phenoxy resin, and   about 0.1 parts by weight to about 10 parts by weight of the (D) photoinitiator,   all amounts based on 100 parts by weight of (A)+(B)+(C).   
     
     
         10 . The adhesive composition according to  claim 1 , wherein the adhesive composition has a viscosity at 25° C. of about 40 cPs to about 135 cPs. 
     
     
         11 . A polarizing plate, comprising:
 a polarizer; and   a protective film stacked on one or both sides of the polarizer via an adhesive layer,   wherein the polarizer has a maximum shrinkage length of about 2 mm or less at one end thereof when the polarizing plate is dipped in water having a constant temperature of 60° C. for 2 hours.   
     
     
         12 . The polarizing plate according to  claim 11 , wherein the adhesive layer is prepared from an adhesive composition for polarizing plates, the adhesive composition including:
 (A) a (meth)acrylate compound,   (B) a cationic epoxy compound,   (C) a phenoxy resin, and   (D) a photoinitiator.   
     
     
         13 . A method for preparing a polarizing plate, the method comprising:
 depositing the adhesive composition according to  claim 1  on one side of a protective film to prepare a protective film having an adhesive composition layer;   stacking the protective film having the adhesive composition layer thereon on both an upper side and a lower side of a polarizer; and   UV irradiating the adhesive composition layer.   
     
     
         14 . An optical member comprising an adhesive film prepared from the adhesive composition as claimed in  claim 1 . 
     
     
         15 . An optical member comprising the polarizing plate as claimed in  claim 11 .