High-clarity blended ionomer compositions and articles comprising the same

A composition comprising an ionomer blend, said ionomer blend comprising, based on the total weight of the ionomer blend, about 5 to about 95 wt % of a first ionomer and about 95 to about 5 wt % of a second ionomer, said ionomer blend having a neutralization level of 10% to 90%, based on the total number of neutralized and unneutralized carboxylic acid groups in the ionomer blend, wherein:

• (A) said first ionomer is the neutralization product of a first precursor acid copolymer;
• and i) the first precursor acid copolymer comprises copolymerized units of a first α-olefin having 2 to 10 carbon atoms and further comprises about 20 to about 30 wt %, based on the total weight of the first precursor acid copolymer, of copolymerized units of a first α,β-ethylenically unsaturated carboxylic acid having 3 to 8 carbon atoms;
• ii) the first precursor acid copolymer has a melt flow rate of about 70 to about 1000 g/10 min;
• and iii) the first precursor acid copolymer, when neutralized to a level of about 40% to about 90% and when comprising counterions that consist essentially of sodium cations, produces a sodium ionomer;
• and said 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 (DSC) in accordance with ASTM D3418;
• (B) said second ionomer is the neutralization product of a second precursor acid copolymer, wherein i) the second precursor acid copolymer comprises copolymerized units of a second α-olefin having 2 to 10 carbon atoms;
• and about 18 to about 30 wt %, based on the total weight of the second precursor acid copolymer, of copolymerized units of a second α,β-ethylenically unsaturated carboxylic acid having 3 to 8 carbon atoms;
• the second α-olefin may be the same as or different from the first α-olefin;
• the amount of the second α-olefin may be the same as or different from the amount of the first α-olefin;
• the second α,β-ethylenically unsaturated carboxylic acid may be the same as or different from the first α,β-ethylenically unsaturated carboxylic acid;
• and the amount of the second α,β-ethylenically unsaturated carboxylic acid may be the same as or different from the amount of the first α,β-ethylenically unsaturated carboxylic acid;
• ii) the second precursor acid copolymer has a melt flow rate of about 60 g/10 min or less;
• and iii) the second ionomer has a melt flow rate of about 10 g/10 min or less at the neutralization level of the ionomer blend;
• and the melt flow rate of the second ionomer at the neutralization level of the ionomer blend is different from the melt flow rate of the first ionomer at the same neutralization level;
• and
• (C) the melt flow rates are determined in accordance with ASTM method D1238 at a polymer melt temperature of 190° C. and under a weight of 2.16 kg.