Multilayer articles and methods for making multilayer articles

Abstract

In one embodiment, a sheet, comprises: a cap layer comprising an acrylic polymer; and a base layer, where the cap layer and the base layer were co-extruded to form the sheet, which is thermoformable. The base layer comprises a polycarbonate. The cap layer is 10% to 30% of an overall thickness and the overall thickness is 5 mil to 500 mil.

1 . A sheet, comprising:
 a cap layer comprising an acrylic polymer, wherein the cap layer is 10% to 30% of an overall thickness and the overall thickness is 5 mil to 500 mil; and   a base layer comprising a polycarbonate;   wherein the cap layer and the base layer were co-extruded to form the sheet, which is thermoformable.   
     
     
         2 . The sheet of  claim 1 , wherein the sheet has a pencil hardness greater than or equal to HB. 
     
     
         3 . The sheet of  claim 1 , wherein the sheet has a pencil hardness greater than or equal to H. 
     
     
         4 . The sheet of  claim 1 , wherein the base layer comprises a copolycarbonate. 
     
     
         5 . The sheet of  claim 2 , wherein the base layer comprises a cycloaliphatic polyester copolymer and a polycarbonate, wherein the cycloaliphatic polyester copolymer is poly(1,4-cyclohexylene dimethylene co-ethylene terephthalate). 
     
     
         6 . The sheet of  claim 1 , wherein the cap layer is on and in contact with the base layer. 
     
     
         7 . The sheet of  claim 1 , wherein the overall thickness is 5 mil to 40 mil. 
     
     
         8 . The sheet of  claim 1 , wherein the sheet is thermoformed at a temperature below the glass transition temperatures of the acrylic polymer and the polycarbonate. 
     
     
         9 . The sheet of  claim 5  wherein the blend comprises 20 wt % to 50 wt % cycloaliphatic polyester, balance polycarbonate. 
     
     
         10 . The sheet of  claim 1 , wherein the acrylic polymer comprises an alkyl(meth)acrylate. 
     
     
         11 . The sheet of  claim 10 , wherein the alkyl(meth)acrylate comprises a poly(methyl)methacrylate. 
     
     
         12 . The sheet of  claim 11 , wherein the poly(methyl)methacrylate has a haze value of less than or equal 5% as determined according to ASTM D1003-00. 
     
     
         13 . A sheet, comprising:
 a cap layer comprising an acrylic polymer, wherein the cap layer is 10% to 30% of an overall thickness and the overall thickness is 5 mil to 500 mil; and   a base layer comprising a cycloaliphatic polyester copolymer and a polycarbonate, wherein the cycloaliphatic polyester copolymer is poly(1,4-cyclohexylene dimethylene co-ethylene terephthalate);   wherein the cap layer and base layer were co-extruded to form the sheet which is thermoformable; and   wherein the sheet has a pencil hardness greater than or equal to HB.   
     
     
         14 . The sheet of  claim 13 , wherein the acrylic polymer comprises an alkyl(meth)acrylate. 
     
     
         15 . The sheet of  claim 14 , wherein the acrylic polymer comprises poly(methyl)methacrylate. 
     
     
         16 . A method for making an article, comprising:
 melting an acrylic polymer in an extruder;   forming a molten mixture comprising a polycarbonate in an extruder;   co-extruding the acrylic polymer and the molten mixture to form a sheet which is thermoformable, wherein the molten mixture forms a base layer and the acrylic polymer forms a cap layer on the base layer;   wherein the cap layer is 10% to 30% of an overall sheet thickness; and   wherein the sheet has a pencil hardness greater than or equal to HB.   
     
     
         17 . The method of  claim 16 , further comprising thermoforming the sheet at a temperature below the glass transition temperatures of the acrylic polymer and the polycarbonate. 
     
     
         18 . The method of  claim 16 , wherein the acrylic polymer comprises an alkyl(meth)acrylate. 
     
     
         19 . The method of  claim 16 , wherein the overall sheet thickness is 3 mil to 20 mil. 
     
     
         20 . The method of  claim 16 , wherein the cap layer is co-extruded on and in contact with the base layer.