Laminated film, and display device including same

Abstract

A laminated film including a first film; and a second film disposed on the first film, wherein a tensile modulus of the second film is greater than or equal to a tensile modulus of the first film, and a transmittance of the first film is greater than or equal to a transmittance of the second film, provided that at least one of the tensile modulus of the first film and the tensile modulus of the second film are not equal or the transmittance of the first film and the transmittance of the second film are not equal.

What is claimed is: 
     
         1 . A laminated film, comprising:
 a first film; and   a second film disposed on the first film;   wherein a tensile modulus of the second film is greater than or equal to a tensile modulus of the first film, and   a transmittance of the first film is greater than or equal to a transmittance of the second film,   provided that at least one of the tensile modulus of the first film and the tensile modulus of the second film are not equal, or the transmittance of the first film and the transmittance of the second film are not equal, the transmittance of the second film is greater than or equal to about 88%, when obtained from Y(D65), and the tensile modulus of the first film is greater than or equal to 4 gigapascals, when measured according to an ASTM D882 standard, and   wherein each of the first film and the second film comprises a poly(amide-imide) copolymer comprising a structural unit represented by Chemical Formula 1 and a structural unit represented by Chemical Formula 2:   
       
         
           
           
               
               
           
         
       
       wherein, in Chemical Formula 1,
 D is a substituted or unsubstituted tetravalent C6 to C24 aliphatic cyclic group, a substituted or unsubstituted tetravalent C6 to C24 aromatic ring group, or a substituted or unsubstituted tetravalent C4 to C24 heteroaromatic ring group, wherein the aliphatic cyclic group, the aromatic ring group, or the heteroaromatic ring group is present as a single ring, a condensed ring system comprising two or more fused rings, or two or more moieties independently selected from the single ring and the condensed ring system that are linked by a single bond, —O—, —S—, —C(═O)—, —CH(OH)—, —S(═O) 2 —, —Si(CH 3 ) 2 —, —(CH 2 ) p —, —(CF 2 ) q —, —C(C n H 2n+1 ) 2 —, —C(C n F 2n+1 ) 2 —, —(CH 2 )p—C(C n H 2n+1 ) 2 —(CH 2 ) q —, —(CH 2 ) p —C(C n F 2n+1 ) 2 —(CH 2 ) 2 —, —C(CF 3 )(C 6 H 5 )—, or —C(═O)NH—, 
 E is a substituted or unsubstituted C1 to C30 alkylene group, a substituted or unsubstituted C2 to C30 alkenylene group, a substituted or unsubstituted C1 to C30 alkynylene group, a substituted or unsubstituted divalent C6 to C24 aliphatic cyclic group, a substituted or unsubstituted divalent C6 to C24 aromatic ring group, or a substituted or unsubstituted divalent C4 to C24 heteroaromatic ring group, wherein the aliphatic cyclic group, the aromatic ring group, or the heteroaromatic ring group is present as a single ring, a condensed ring system comprising two or more fused rings, or two or more moieties independently selected from the single ring and the condensed ring system that are linked by a single bond, a fluorenylene group, —O—, —S—, —C(═O)—, —CH(OH)—, —S(═O) 2 —, —Si(CH 3 ) 2 —, —(CH 2 ) p —, —(CF 2 ) q —, -—(C n H 2+1 ) 2 —, —C(C n F 2n+1 ) 2 —, —(CH 2 ) p —C(C n H 2n+1 ) 2 —(CH 2 ) q —, or —(CH 2 ) p —C(C n F 2n+1 ) 2 —(CH 2 ) q —, —C(CF 3 )(C 6 H 5 )—, or —C(═O)NH—, and 
 1≤n≤10, 1≤p≤10, and 1≤q≤10, 
 
       
         
           
           
               
               
           
         
       
       wherein, in Chemical Formula 2,
 each of A and B′ are independently a substituted or unsubstituted C1 to C30 alkylene group, a substituted or unsubstituted C2 to C30 alkenylene group, a substituted or unsubstituted C1 to C30 alkynylene group, a substituted or unsubstituted divalent C6 to C24 aliphatic cyclic group, a substituted or unsubstituted divalent C6 to C24 aromatic ring group, or a substituted or unsubstituted divalent C4 to C24 heteroaromatic ring group, wherein the aliphatic cyclic group, the aromatic ring group, or the heteroaromatic ring group is present as a single ring, a condensed ring system comprising two or more fused rings, or two or more moieties independently selected from the single ring and the condensed ring system that are linked by a single bond, a fluorenylene group, —O—, —S—, —C(═O)—, —CH(OH)—, —S(═O) 2 —, —Si(CH 3 ) 2 —, —(CH 2 ) p —, —(CF 2 ) q —, —C(C n H 2n+1 ) 2 —, —C(C n F 2n+1 ) 2 —, —(CH 2 ) p —C(C n H 2n+1 ) 2 —(CH 2 ) q —, —(CH 2 ) p —C(C n F 2n+1 ) 2 —(CH 2 ) q —, —C(CF 3 )(C 6 H 5 )—, or —C(═O)NH—, and 
 wherein 1≤n≤10, 1≤p≤10, and 1≤q≤10. 
 
     
     
         2 . The laminated film of  claim 1 , wherein the tensile modulus of the second film is greater than or equal to about 5 gigapascals, when measured according to an ASTM D882 standard. 
     
     
         3 . The laminated film of  claim 1 , wherein the transmittance of the first film is greater than or equal to about 89%, when obtained from Y(D65). 
     
     
         4 . The laminated film of  claim 1 , wherein a refractive index of the second film is greater than a refractive index of the first film. 
     
     
         5 . The laminated film of  claim 1 , wherein the laminated film further comprises a hard coating layer disposed on the second film on a side opposite the first film. 
     
     
         6 . The laminated film of  claim 1 , wherein the laminated film further comprises a back coating layer disposed on the first film on a side opposite the second film. 
     
     
         7 . The laminated film of  claim 1 , wherein the laminated film further comprises an adhesive layer or a hyperelastic layer disposed between the first film and the second film. 
     
     
         8 . The laminated film of  claim 7 , wherein the laminated film further comprises a second back coating layer disposed between the second film and the adhesive layer or the hyperelastic layer. 
     
     
         9 . The laminated film of  claim 7 , wherein the laminated film further comprises a primer coating layer disposed between the first film and the adhesive layer or the hyperelastic layer. 
     
     
         10 . The laminated film of  claim 5 , wherein the hard coating layer comprises a (meth)acrylate polymer, a polycaprolactone, a urethane-(meth)acrylate copolymer, a polyrotaxane, an epoxy resin, an organosilicon material, an inorganic hard coating material, or a combination thereof. 
     
     
         11 . The laminated film of  claim 1 , wherein each of a thickness of the first film and a thickness of the second film is independently about 10 micrometers to about 100 micrometers. 
     
     
         12 . The laminated film of  claim 7 , wherein a thickness of the adhesive layer or a thickness of the hyperelastic layer is less than or equal to about 50 micrometers. 
     
     
         13 . The laminated film of  claim 1 , wherein the poly(amide-imide) copolymer of the first film and the poly(amide-imide) copolymer of the second film each independently comprises:
 about 20 mole percent to about 70 mole percent of at least one structural unit represented by Chemical Formula 1 based on a total amount of structural units of the poly(amide-imide) copolymer, and   about 30 mole percent to about 80 mole percent of at least one structural unit represented by Chemical Formula 2 based on the total amount of structural units of the poly(amide-imide) copolymer.   
     
     
         14 . The laminated film of  claim 1 ,
 wherein the poly(amide-imide) copolymer of the second film comprises about 50 mole percent to about 80 mole percent of at least one structural unit represented by Chemical Formula 2, based on the total amount of structural units of the poly(amide-imide) copolymer, and   wherein the poly(amide-imide) copolymer of the first film comprises less than 50 mole percent of at least one structural unit represented by Chemical Formula 2, based on the total amount of structural units of the poly(amide-imide) copolymer.   
     
     
         15 . The laminated film of  claim 1 , wherein the first film further comprises a polyimide, polyamide, polyethylene terephthalate, polyethylene naphthalate, a polycarbonate, triacetyl cellulose, or a combination thereof. 
     
     
         16 . The laminated film of  claim 1 , wherein D of Chemical Formula 1 is a moiety represented by one or more of chemical formulae of Formula Group 1: 
       
         
           
           
               
               
           
         
         wherein, in the chemical formulae of Formula Group 1, 
         the moiety is substituted or unsubstituted, 
         each L is the same or different and is independently a single bond, —O—, —S—, —C(═O)—, —CH(OH)—, —S(═O) 2 —, —Si(CH 3 ) 2 —, —(CH 2 ) p —, —(CF 2 ) q —, —C(C n H 2n+1 ) 2 —, —C(C n F 2n+1 ) 2 —, —(CH 2 ) p —C(C n H 2n+1 ) 2 —(CH 2 ) q —, —(CH 2 ) p —C(C n F 2n+1 ) 2 —(CH 2 ) q —, —C(CF 3 )(C 6 H 5 )—, or —C(═O)NH—, wherein 1≤n≤10, 1≤p≤10, and 1≤q≤10, 
         * is a linking portion with an adjacent atom, 
         Z 1  and Z 2  are the same or different and are independently —N═ or —C(R 100 )═, wherein R 100  is hydrogen or a C1 to C5 alkyl group, provided that Z 1  and Z 2  are not simultaneously —C(R 100 )═, and 
         Z 3  is —O—, —S—, or —NR 101 —, wherein R 101  is hydrogen or a C1 to C5 alkyl group.