| 摘要 |
<p>Heat seal compositions and articles including the compositions are disclosed. The compositions exhibit a broad tempeature range for making heat seals of variable strengths and are useful as the sole heat seal composition in making flexible packages requiring both permanent and peelable seals. The compositions, which are substantially homogeneous blends of polymeric materials comprise (a) 20 to 80 percent, by weight, of a terpolymer having as monomeric components, i) 65 to 95 percent, by weight, ethylene, ii) 4 to 30 percent, by weight, vinyl alkanoate or an ester selected from the group consisting of alkyl acrylate, and alkyl methacrylate wherein the alkanoic acid moiety of the alkanoate and the alkyl group have one to four carbon atoms, and iii) 0.5 to 20 percent, by weight ethylenically unsaturated monocarboxylic acid selected from the group consisting of acrylic acid and methacrylic acid; and (b) 20 to 80 percent, by weight of an ionomer having, as monomeric components, i) 75 to 99 percent, by weight, ethylene, ii) 1 to 25 percent, by weight, ethylenically unsaturated monocarboxylic acid selected from the group consisting of acrylic acid and methacrylic acid wherein the sum of the weight percentages of comonomers ii and iii in the terpolymer is at least eight percentage points higher than the weight percentage of comonomer ii in the ionomer, wherein 5 to 75 percent of the carboxylic acid groups in the ionomer is neutralized by zinc ions, and wherein 5 to 40 percent of all of the carboxylic acid groups in the blend is neutralized by zinc ions.</p> |
