Acrylic Thermoplastic Resin Composition and Molded Article Thereof

Abstract

An acrylic thermoplastic resin composition includes a first acrylic resin having a first structural unit represented by the following formula (1) and a second structural unit represented by the following formula (2), and a second acrylic resin having the first structural unit represented by the following formula (1) and a third structural unit represented by the following formula (3), in which a total content of the first unit is 50 to 95 mass % and a total content of the second structural unit and the third structural unit is 5 to 50 mass % based on a total amount of the first acrylic resin and the second acrylic resin:

1 . An acrylic thermoplastic resin composition comprising:
 a first acrylic resin having a first structural unit represented by the following formula (1) and a second structural unit represented by the following formula (2); and   a second acrylic resin having the first structural unit represented by the following formula (1) and a third structural unit represented by the following formula (3), wherein   a total content of the first unit is 50 to 95 mass % and a total content of the second structural unit and the third structural unit is 5 to 50 mass % based on a total amount of the first acrylic resin and the second acrylic resin,   
       
         
           
           
               
               
           
         
       
       wherein R 1  represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 5 to 12 carbon atoms, an arylalkyl group having 7 to 14 carbon atoms, an aryl group having 6 to 14 carbon atoms, or an aryl group having 6 to 14 carbon atoms with at least one substituent selected from the following Group A:
 Group A: a halogen atom, a hydroxyl group, a nitro group, an alkoxy group having 1 to 12 carbon atoms and an alkyl group having 1 to 12 carbon atoms; 
 
       
         
           
           
               
               
           
         
       
       wherein R 2  represents an arylalkyl group having 7 to 14 carbon atoms, an aryl group having 6 to 14 carbon atoms, or an aryl group having 6 to 14 carbon atoms with at least one substituent selected from the following Group B, and R 3  and R 4  each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 14 carbon atoms:
 Group B: a halogen atom, a hydroxyl group, a nitro group, an alkoxy group having 1 to 12 carbon atoms, an alkyl group having 1 to 12 carbon atoms, and an arylalkyl group having 7 to 14 carbon atoms; 
 
       
         
           
           
               
               
           
         
       
       wherein R 5  represents a hydrogen atom, a cycloalkyl group having 3 to 12 carbon atoms, an alkyl group having 1 to 12 carbon atoms, or an alkyl group having 1 to 12 carbon atoms with at least one substituent selected from the following Group C, and R 6  and R 7  each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or an aryl group having 6 to 14 carbon atoms:
 Group C: a halogen atom, a hydroxyl group, a nitro group and an alkoxy group having 1 to 12 carbon atoms, wherein the acrylic thermoplastic resin has: 
 an absolute value of a photoelastic coefficient of 3.0×10 −12  Pa −1  or less; and 
 an absolute value of retardation (Re) in an in-plane direction of 30 nm or less in terms of a thickness of 100 μm when shaped into a film. 
 
     
     
         2 . The acrylic thermoplastic resin composition according to  claim 1 , wherein a content of the second structural unit is 0.1 to 49.9 mass % and a content of the third structural unit is 0.1 to 49.9 mass % based on a total amount of the first acrylic resin and the second acrylic resin. 
     
     
         3 . The acrylic thermoplastic resin composition according to  claim 1 , wherein the first acrylic resin has, based on a total amount thereof, 50 to 95 mass % of the first structural unit and 5 to 50 mass % of the second structural unit. 
     
     
         4 . The acrylic thermoplastic resin composition according to  claim 1 , wherein the second acrylic resin has, based on a total amount thereof, 50 to 95 mass % of the first structural unit and 5 to 50 mass % of the third structural unit. 
     
     
         5 . The acrylic thermoplastic resin composition according to  claim 1 , wherein the R 1  is a methyl group or a benzyl group, the R 2  is a phenyl group or a phenyl group with at least one substituent selected from the Group B, and the R 5  is a cyclohexyl group. 
     
     
         6 . The acrylic thermoplastic resin composition according to  claim 1 , wherein the first acrylic resin has a weight average molecular weight Mw of 3000 to 1000000 and a ratio Mw/Mn of the weight average molecular weight Mw to a number average molecular weight Mn of 1 to 10 in terms of polymethyl methacrylate, which are measured by a GPC measuring method. 
     
     
         7 . The acrylic thermoplastic resin composition according to  claim 1 , wherein the second acrylic resin has a weight average molecular weight Mw of 3000 to 1000000 and a ratio Mw/Mn of the weight average molecular weight Mw to a number average molecular weight Mn of 1 to 10 in terms of polymethyl methacrylate, which are measured by a GPC measuring method. 
     
     
         8 . (canceled) 
     
     
         9 . The acrylic thermoplastic resin composition according to  claim 1 , wherein, when shaped into a uniaxially-stretched film, a slope K in the following linear relational equation (a) by least squares approximation satisfies the following equation (b):
   Δ n=K×S+C   (a)
     | K| 0.30×10 −5   (b)
   
       wherein a birefringence in terms of a thickness of 100 μm of the uniaxially-stretched film is defined as Δn, a stretch ratio is defined as S, and C is a constant number and represents birefringence when not being stretched. 
     
     
         10 . (canceled) 
     
     
         11 . The acrylic thermoplastic resin composition according to  claim 1 , wherein an absolute value of retardation Rth in a thickness direction is 30 nm or less in terms of a thickness of 100 μm, when shaped into a film. 
     
     
         12 . The acrylic thermoplastic resin composition according to  claim 1 , wherein a glass-transition temperature Tg is 120° C. or more. 
     
     
         13 . The acrylic thermoplastic resin composition according to  claim 1 , wherein a total light transmittance is 85% or more in terms of a thickness of 100 μm, when shaped into a film. 
     
     
         14 . A shaped article comprising the acrylic thermoplastic resin composition according to  claim 1 . 
     
     
         15 . A film-like or sheet-like shaped article comprising the acrylic thermoplastic resin composition according to  claim 1 . 
     
     
         16 . A film-like or sheet-like shaped article prepared by stretching at least in a uniaxial direction a resin sheet comprising the acrylic thermoplastic resin according to  claim 1  and shaped by extrusion. 
     
     
         17 . A film-like or sheet-like shaped article prepared by stretching at least in a uniaxial direction a resin sheet comprising the acrylic thermoplastic resin according to  claim 1  and shaped by solution casting. 
     
     
         18 . A polarizing plate protection film comprising the shaped article according to  claim 14 . 
     
     
         19 . A retardation film comprising the shaped article according to  claim 14 . 
     
     
         20 . A retardation plate comprising the shaped article according to  claim 14 . 
     
     
         21 . A transparent plastic substrate comprising the shaped article according to  claim 14 . 
     
     
         22 . A lens comprising the shaped article according to  claim 14 . 
     
     
         23 . The acrylic thermoplastic resin composition according to  claim 1 , wherein an average molecular weight difference between the first acrylic resin and the second acrylic resin is 10000 or more. 
     
     
         24 . The acrylic thermoplastic resin composition according to  claim 1 , wherein a weight-average molecular weight of the resin with higher Tg from the first and second acrylic resins is lower than that of the resin with lower Tg from the first and second acrylic resins. 
     
     
         25 . The acrylic thermoplastic resin composition according to  claim 1 , wherein a refractive index difference between the first acrylic resin and the second acrylic resins is less than 0.04.