Use of derivatives of polyamino acids as emulsifiers stabilizers in aqueous free radical emulsion polymerization

A method for making a polymer which comprises polymerizing from about 10% to about 80%, by weight, of an emulsion polymerizable ethylenically unsaturated monomer in an aqueous medium by free radical initiated polymerization in the presence of:

• (a) from about 0.1% to about 10% by weight of a polyamino acid heteropolymer;
• and
• (b) from about 0.01% to about 1% by weight of a free radical polymerization initiating agent;
• to form a stabilized aqueous emulsion polymerization composition, wherein the polyamino acid heteropolymer in (b) may be selected from the group consisting of polyaspartic acid heteropolymers represented by Formula (1):
• ##STR13## and polyglutamic acid heteropolymers represented by Formula (2):
• ##STR14## and copolymers of the polyaspartic acid heteropolymers represented by Formula (1) with the polyglutamic acid heteropolymers represented by Formula (2), and mixtures thereof;
• wherein
• (i) R.sub.1 is selected from the group consisting of branched and unbranched alkyl, alkylaryl, and alkenyl groups having from 4 to 30 carbon atoms, and alkyl terminated polymers of ethylene oxide, propylene oxide, and butylene oxide having a molecular weight in the range from about 200 to about 3000;
• (ii) R.sub.2 is selected from the group consisting of hydrogen and branched and unbranched alkyl and alkenyl groups having from 1 to 4 carbon atoms;
• (iii) M.sup.+ is a cation;
• (iv) residues n.sub.1, n.sub.2, n.sub.3, and n.sub.4 are present in random order, and the ratio of (n.sub.1 +n.sub.3):(n.sub.2 +n.sub.4) is from about 1:99 to about 1:1;
• and
• (v) the molecular weight of the polyamino acid heteropolymer is from about 1,000 to about 100,000.

A stabilized aqueous emulsion polymerization composition prepared by a method which comprises polymerizing from about 10% to about 80%, by weight, of an emulsion polymerizable ethylenically unsaturated monomer in an aqueous medium by free radical initiated polymerization in the presence of:

• (a) from about 0.1% to about 10% by weight of a polyamino acid heteropolymer;
• and
• (b) from about 0.01% to about 1% by weight of a free radical polymerization initiating agent;
• to form a stabilized aqueous emulsion polymerization composition, wherein the polyamino acid heteropolymer in (b) may be selected from the group consisting of polyaspartic acid heteropolymers represented by Formula (1):
• ##STR15## and polyglutamic acid heteropolymers represented by Formula (2):
• ##STR16## and copolymers of the polyaspartic acid heteropolymers represented by Formula (1) with the polyglutamic acid heteropolymers represented by Formula (2), and mixtures thereof;
• wherein
• (i) R.sub.1 is selected from the group consisting of branched and unbranched alkyl, alkylaryl, and alkenyl groups having from 4 to 30 carbon atoms, and alkyl terminated polymers of ethylene oxide, propylene oxide, and butylene oxide having a molecular weight in the range from about 200 to about 3000;
• (ii) R.sub.2 is selected from the group consisting of hydrogen and branched and unbranched alkyl and alkenyl groups having from 1 to 4 carbon atoms;
• (iii) M.sup.+ is a cation;
• (iv) residues n.sub.1, n.sub.2, n.sub.3, and n.sub.4 are present in random order, and the ratio of (n.sub.1 +n.sub.3):(n.sub.2 +n.sub.4) is from about 1:99 to about 1:1;
• and
• (v) the molecular weight of the polyamino acid heteropolymer is from about 1,000 to about 100,000.