Patent ID: 8263706

Claim:
An acrylic polymeric composition comprising a melt blend of a thermoplastic high molecular weight acrylic material (HMWA) and a thermoplastic low molecular weight acrylic material (LMWA), at least 70% w/w, based on the total weight of the HMWA, of the said HMWA comprising an alkyl(alk)acrylate (co)polymer, the said (co)polymer comprising at least 80% w/w of a first polymer unit derived from C 1 -C 12 alkyl (C 1 -C 8 alk)acrylate monomer units and optionally, up to 20% w/w, based on the said alkyl(alk)acrylate (co)polymer of a first copolymer unit derived from C 1 -C 12 alkyl (C 0 -C 8 alk) acrylate and/or (C 0 -C 8 alk) acrylic acid monomer units, the said HMWA having a weight average molecular weight of between 40 k Daltons and 1000 k Daltons, at least 70% w/w, based on the total weight of the LMWA, of the said LMWA comprising an alkyl(alk)acrylate (co)polymer, the said (co)polymer comprising at least 80% w/w of a second polymer unit derived from C 1 -C 12 alkyl (C 1 -C 8 alk)acrylate monomer units and optionally, up to 20% w/w, based on the said alkyl(alk)acrylate (co)polymer of a second copolymer unit derived from C 1 -C 12 alkyl (C 0 -C 8 alk)acrylate and/or (C 0 -C 8 alk)acrylic acid monomer units, the said LMWA having a weight average molecular weight of between the entanglement molecular weight (M e ) (expressed in k Daltons) and 250 k Daltons, with the proviso that the HMWA has a higher M w than the LMWA, wherein the first polymer unit of the HMWA and the second polymer unit of the LMWA are the same, and wherein the composition has less than 0.5% w/w of impact strength modifier.