Aqueous coating compositions for barrier coatings, coated packaging material, and method

An aqueous coating composition, comprising:

• water, poly(vinyl alcohol-vinyl primary amine), poly(methyl vinyl ether-maleic anhydride), and a Ca++ microgranulated bentonite clay,
• wherein the poly(vinyl alcohol-vinyl primary amine) is from about 90 to about 98.5 weight percent of total nonvolatile weight of the aqueous coating composition,
• wherein the combined weight of poly(methyl vinyl ether-maleic anhydride) and the Ca++ microgranulated bentonite clay is from about 1.5 to about 10 weight percent of nonvolatile content of the aqueous coating composition,
• wherein the weight ratio of the poly(methyl vinyl ether-maleic anhydride) to the Ca++ microgranulated bentonite clay is from about 20:80 to about 80:20, and
• wherein the poly(methyl vinyl ether-maleic anhydride) is at least 0.8 weight percent of the nonvolatile content of the aqueous coating composition and/or has a weight average molecular weight of at least about 1,000,000 Daltons.

A packaging material having a coating thereon, wherein the coating comprises poly(vinyl alcohol-vinyl primary amine), poly(methyl vinyl ether-maleic anhydride), and a Ca++ microgranulated bentonite clay;

• wherein the poly(vinyl alcohol-vinyl primary amine) is from about 90 to about 98.5 weight percent of the coating;
• wherein the combined weight of poly(methyl vinyl ether-maleic anhydride) and the Ca++ microgranulated bentonite clay is from about 1.5 to about 10 weight percent of the coating;
• wherein the weight ratio of the poly(methyl vinyl ether-maleic anhydride) to the Ca++ microgranulated bentonite clay is from about 20:80 to about 80:20;
• and
• wherein the poly(methyl vinyl ether-maleic anhydride) either:
• (a) is at least 0.8 weight percent of the coating or
• (b) has a weight average molecular weight of at least about 1,000,000 Daltons.