Aqueous dispersion of copolymer particles of vinyl acetate and a cyclic ketene acetal monomer

A composition comprising an aqueous dispersion of copolymer particles having a z-average particle size in the range of from 50 nm to 500 nm, which polymer particles comprise, based on the weight of the copolymer particles, a) from 75 to 98.5 weight percent structural units of vinyl acetate;

• b) from 1 to 20 weight percent structural units of a cyclic ketene acetal monomer;
• and c) from 0.05 to 5 weight percent structural units of a monoethylenically unsaturated acid monomer, or a salt thereof;
• wherein the cyclic ketene acetal monomer is characterized by following structure:
• where n is 0, 1, or 2;
• R is H or C1-C6-alkyl;
• R1 and R2 are each independently H, C1-C12-alkyl, phenyl, or vinyl;
• or R1 and R2 together with the carbon atoms to which they are attached, form a fused benzene ring or a fused C3-C7-cycloaliphatic ring;
• and
• R1′ and R2′ are each independently H or C1-C12-alkyl;
• or R1 and R1′ and/or R2 and R2′ form an exocyclic double bond;
• with the proviso that when n is 1:
• R3 and R3′ are each independently H, C1-C12-alkyl, phenyl, or R3 and R3′ form an exocyclic double bond or a spirocycloaliphatic group or spiro-2-methylene-1,3-dioxepane group;
• with the further proviso that when n is 2:
• each R3 is H, C1-C12-alkyl, or together with the carbon atoms to which they are attached form a double bond, a fused benzene ring, or a fused C3-C7-cycloaliphatic ring.