Aqueous dispersion of acrylate-siloxane copolymer particles

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 and comprising, based on the weight of the copolymer particles, a) from 40 to 98.8 weight percent structural units of an acrylate monomer;

• b) from 0.1 to 5 weight percent structural units of an acid monomer;
• and c) from 1 to 59.8 weight percent structural units of a siloxane-acrylate monomer of formula I:
• where R is H or CH3;
• R1 is H or CH3;
• each R2 is independently CH3 or O—Si(CH3)3;
• Y is —CH2— or —CH2CH2—;
• and
• x is 0 or 1;
• with the proviso that when x is 1, R1 is H;
• when Y is —CH2—, R1 is H;
• and when Y is —CH2CH2—, R1 is CH3 and x is 0;
• wherein the solids content of the copolymer particles in the aqueous dispersion is in the range of 30 to 55 weight percent and a) the aqueous phase of the aqueous dispersion comprises not greater than 1000 ppm of monomer of formula I;
• or b) the aqueous phase of the aqueous dispersion comprises not greater than 10000 ppm of coagulum;
• wherein the composition further comprises
• a) from 0.5 to 5 weight percent, based on the weight of the copolymer particles, of a nonionic surfactant of formula II:
• where n is from 0 to 10;
• p is from 2 to 30, with the proviso that p≥n;
• and R3 is a linear or branched C3-C16-alkyl group;
• and
• b) from 0.5 to 5 weight percent, based on the weight of the copolymer particles of an anionic surfactant of formula III:
• where R4 is C6-C20-alkyl;
• m is from 0 to 10;
• and M is Li, Na, or K.