Patent ID: 7781062

Claim:
A multilayer structure polymer (I) comprising (1) an innermost layer polymer (I-A), (2) an intermediate layer polymer (I-B) with a glass-transition temperature of 25 to 100° C. comprising a composition different from that of the innermost layer polymer (I-A), and (3) an outermost layer polymer (I-C), wherein the innermost layer polymer comprises (I-A1) an alkyl acrylate in 50 to 99.9 wt %, (I-A2) an alkyl methacrylate in 0 to 49.9 wt %, (I-A3) another monomer comprising a copolymerizable double bond in 0 to 20 wt %, (I-A4) a multifunctional monomer in 0 to 10 wt %, and (I-A5) a graft crosslinker in 0.1 to 10 wt %; wherein the intermediate layer polymer (I-B) comprises (I-B1) an alkyl acrylate in 9.9 to 90 wt %, (I-B2) an alkyl methacrylate in 9.9 to 90 wt %, (I-B3) another monomer comprising a copolymerizable double bond in 0 to 20 wt %, (I-B4) a multifunctional monomer in 0 to 10 wt %, and (I-B5) a graft crosslinker 0.1 to 10 wt %; and wherein the outermost layer polymer (I-C) comprises (I-C1) an alkyl methacrylate in 80 to 100 wt %, (I-C2) an alkyl acrylate in 0 to 20 wt %, and (I-C3) another monomer comprising a copolymerizable double bond in 0 to 20 wt %.