Resin composition and molded article composed of the same

Abstract

A resin composition comprising a polylactic acid-based resin (A) and methacrylic resins (B), wherein the methacrylic resins having at least (a) a difference of 10° C. or more in glass transition temperature or (b) a difference of 3% or more in syndiotacticity; it is preferred that at least one of the methacrylic resins (B) is a methacrylic resin having a weight average molecular weight of 50,000 to 450,000, a glass transition temperature of 110° C. or higher and a syndiotacticity of 40% or more, and that the resin composition further contains a multilayer structure polymer formed as particles each consisting of a core layer and one or more shell layers covering it (C). A molded article made of said resin composition.

1 . A resin composition comprising
 (A) a polylactic acid resin and   (B) a methacrylic resin,   wherein the ratio (syndiotacticity/isotacticity) of the syndiotacticity to the isotacticity of the methacrylic resin (B) in the resin composition is 3.0 to 8.0.   
     
     
         2 . The resin composition, according to  claim 1 , wherein at least one of the methacrylic resins (B) is a methacrylic resin with a weight average molecular weight of 50,000 to 450,000, a glass transition temperature of 110° C. or higher and a syndiotacticity of 40% or more. 
     
     
         3 . The resin composition, according to  claim 1 , further comprising (C) a multilayer structure polymer formed from particles each consisting of a core layer and at least one or more shell layers covering the core layer. 
     
     
         4 . The resin composition, according to  claim 3 , wherein the multilayer structure polymer (C) satisfies at least one of the following conditions: (c) the polymer has a refractive index of 1.45 to 1.50 and/or (d) the polymer contains a component with a glass transition temperature of 30° C. or lower. 
     
     
         5 . The resin composition, according to  claim 3 , wherein the outermost layer of the multilayer structure polymer (C) is formed of a polymer containing methyl methacrylate units and/or methyl acrylate units. 
     
     
         6 . The resin composition, according to  claim 3 , wherein the dispersed particle size of the multilayer structure polymer (C) in the resin composition is 1 to 1,000 nm. 
     
     
         7 . The resin composition, according to  claim 3 , wherein the ratio (l/m) of the number of agglomerated particles (l) to the number of non-agglomerated particles (m) of the multilayer structure polymer (C) in the resin composition is 0 to 0.5. 
     
     
         8 . The resin composition, according to  claim 1 , wherein further a reactive compound containing at least one type of functional groups selected from glycidyl groups, acid anhydride groups, carbodiimide groups and oxazoline groups is mixed as a reactive compound (D). 
     
     
         9 . The resin composition, according to  claim 8 , wherein the reactive compound (D) is a polymer having a weight average molecular weight of 1,000 to 300,000 and containing glycidyl group-containing vinyl units. 
     
     
         10 . The resin composition, according to  claim 1 , wherein further inorganic particles (E) are comprised, the length of the minor axes of the inorganic particles in the resin composition being 1 to 300 nm, and the length of the major axes being 1 to 1,000 nm. 
     
     
         11 . The resin composition, according to  claim 10 , wherein the inorganic particles (E) contain silicon. 
     
     
         12 . A molded article made of the resin composition as set forth in  claim 1 . 
     
     
         13 . A molded article made of the resin composition as set forth in  claim 3 . 
     
     
         14 . A molded article made of the resin composition as set forth in  claim 8 . 
     
     
         15 . A molded article made of the resin composition as set forth in  claim 10 .