Acid-functionalized copolymers of methyl methacrylate and acrylic resin compositions based thereon

Abstract

Acid-functionalized copolymers of methyl methacrylate having relatively high glass transition temperatures and molecular weights may be employed to manufacture articles having high light transmission values, low haze, high heat resistance, and high environmental stability, which are useful as optical protection films, zero-zero optical retardation films, and compensation films as well as lighting pipes and optical imaging lenses.

1 . A copolymer of methyl methacrylate, methacrylic acid and, optionally, at least one additional co-monomer, having a weight average molecular weight of at least 60,000 g/mole and a glass transition temperature of at least 115° C. 
     
     
         2 . The copolymer of  claim 1 , having a weight average molecular weight of at least 80,000 g/mole. 
     
     
         3 . The copolymer of  claim 1 , having a weight average molecular weight of at least 100,000 g/mole. 
     
     
         4 . The copolymer of  claim 1 , having a glass transition temperature of at least 120° C. 
     
     
         5 . The copolymer of  claim 4 , having a glass transition temperature of at least 130° C. 
     
     
         6 . The copolymer of  claim 1 , having a refractive index of 1.45-1.53 at a wavelength of 589 nm. 
     
     
         7 . The copolymer of  claim 1 , wherein the at least one additional co-monomer is selected from the group consisting of ethyl acrylate, methyl acrylate, styrene, alpha-methyl styrene, cyclic and aliphatic unsaturated anhydrides, benzyl methacrylate, cyclohexyl methacrylate, tert-butyl cyclohexyl methacrylate, tert-butyl methacrylate, vinyl esters, vinyl neodecanoate, vinyl neononanate, and combinations thereof. 
     
     
         8 . The copolymer of  claim 1 , wherein the copolymer is selected from the group consisting of methyl methacrylate/methacrylic acid copolymers, methyl methacrylate/methacrylic acid/ethyl acrylate copolymers, methyl methacrylate/methacrylic acid/methyl acrylate copolymers, methyl methacrylate/methacrylic acid/tert-butyl cyclohexyl methacrylate copolymers, methyl methacrylate/methacrylic acid/isobornyl methacrylate copolymers, methyl methacrylate/methacrylic acid/styrene copolymers, methyl methacrylate/methacrylic acid/styrene/maleic: anhydride copolymers, methyl methacrylate/methacrylic acid/maleic anhydride/alpha-methyl styrene copolymers, methyl methacrylate/methacrylic acid/ethyl acrylate/benzyl methacrylate copolymers, methyl methacrylate/methacrylic acid/benzyl methacrylate/text-butyl cyclohexyl methacrylate copolymers, methyl methacrylate/methacrylic acid/benzyl methacrylate/tort-butyl cyclohexyl methacrylate copolymers methyl methacrylate/methacrylic acid/ethyl acrylate/tort-butyl methacrylate copolymers and combinations thereof. 
     
     
         9 . The copolymer of  claim 1 , wherein methacrylic acid comprises from about 1 to about 7 weight % of the copolymer. 
     
     
         10 . The copolymer of  claim 1 , wherein methyl methacrylate comprises from about 70 to about 99 weight % of the copolymer. 
     
     
         11 . The copolymer of  claim 1 , wherein the copolymer is comprised of about 79 to about 99% by weight methyl methacrylate, about 1 to about 7% by weight methacrylic acid, and 0 to about 20% by weight in total of at least one additional co-monomer. 
     
     
         12 . The copolymer of  claim 1 , wherein the copolymer has a light transmission of at least about 88%, and less than 10% haze when measured by ASTM D1003 on a 3.2 mm thick plaque. 
     
     
         13 . The copolymer of  claim 1 , wherein the copolymer has a melt flow rate of about 0.3 to about 2.5 g/10 minutes at 230° C. under 3.8 kg. 
     
     
         14 . An acrylic resin composition, comprising at least one copolymer in accordance with  claim 1 , and further comprising at least one additive selected from the group consisting of antioxidant, UV stabilizer, and toughening agent. 
     
     
         15 . The acrylic resin composition of  claim 14 , wherein said at least one antioxidant selected from the group consisting of phosphite antioxidants, phosphate antioxidants, phosphonate antioxidants, phosphine antioxidants, phenolic antioxidants, triazinetrione antioxidants and combinations thereof. 
     
     
         16 . (canceled) 
     
     
         17 . The acrylic resin composition of  claim 14 , wherein said at least one UV stabilizer is selected from the group consisting of benzophenone UV stabilizers, benzotriazole UV stabilizers, hydroxyphenyl benzotriazole UV stabilizers, hydroxyphenyl triazine UV stabilizers, benzoxazinone UV stabilizers and combinations thereof. 
     
     
         18 . (canceled) 
     
     
         19 . The acrylic resin composition of  claim 14 , wherein the at least one toughening agent is selected from the group consisting of block copolymer toughening agents and core-shell toughening agents. 
     
     
         20 . An acrylic resin composition, comprising at least one copolymer in accordance with  claim 1  further comprising at least one additional polymer selected from the group consisting of copolymers of methyl methacrylate and one or more C 1 -C 4  alkyl esters of acrylic acid. 
     
     
         21 . The acrylic resin composition of  claim 20 , wherein the at least one additional polymer is a copolymer of methyl methacrylate and at least one comonomer selected from ethyl acrylate or methyl acrylate. 
     
     
         22 . The acrylic resin composition of  claim 20 , wherein the acrylic resin is comprised of from about 25% by weight to about 99.9% by weight of said copolymer and from 0.1% by weight to about 75% by weight of said additional polymer, based on the total weight of copolymer and additional polymer. 
     
     
         23 . The acrylic resin composition of  claim 1 , wherein the at least one additional polymer has a weight average molecular weight of at least 100,000 g/mole. 
     
     
         24 . The acrylic resin composition of  claim 23 , wherein the at least one additional polymer has a weight average molecular weight of at least 120,000 g/mole. 
     
     
         25 . An acrylic resin composition comprising at least one copolymer in accordance with  claim 1 , wherein anhydride ring structures are present. 
     
     
         26 . The acrylic resin composition of  claim 25 , containing 0.5 to 2% by weight anhydride ring structures as measured by  13 C NMR.