Patent ID: 8334033

Claim:
A composition comprising a sodium/zinc mixed ionomer, wherein said sodium/zinc mixed ionomer is the neutralization product of a precursor acid copolymer; and wherein (a) the precursor acid copolymer comprises copolymerized units of ethylene and about 20 to about 30 wt % of copolymerized units of an α,β-ethylenically unsaturated carboxylic acid selected from the group consisting of acrylic acid and methacrylic acid, based on the total weight of the precursor acid copolymer; wherein the precursor acid copolymer has a melt flow rate of about 10 to about 4000 g/10 min, as determined in accordance with ASTM D1238 at 190° C. and 2.16 kg; wherein the precursor acid copolymer, being neutralized to a level of about 40% to about 90% based on the total number of the carboxylic acid groups present in the precursor acid copolymer, produces a sodium ionomer, said sodium ionomer comprising carboxylate groups and counterions, and said counterions consisting essentially of sodium ions; and wherein the sodium ionomer has a melt flow rate of about 0.7 to about 25 g/10 min and a freeze enthalpy that is not detectable or that is less than about 3.0 j/g, when determined by differential scanning calorimetry in accordance with ASTM D3418; and (b) said sodium/zinc mixed ionomer comprises carboxylate groups and a combination of counterions; said combination of counterions consisting essentially of about 1 to about 99 equivalent % of sodium cations and about 99 to about 1 equivalent % of zinc cations, based on the total number of equivalents of carboxylate groups in the sodium/zinc mixed ionomer.