Silicone emulsions which crosslink by Michael addition reactions

An aqueous silicone emulsion which crosslinks by a Michael addition reaction, yielding a cured composition upon removal of water, comprising:

• (A) a dispersed phase comprising an organosiloxane polymer having the general formula ##STR4## where R is individually selected from the group consisting of hydrogen, 3,3,3-trifluoropropyl radicals and monovalent hydrocarbon radicals having from 1 to 15 carbon atoms;
• L is individually selected from the group consisting of hydrogen, a hydroxyl group, and a hydrolyzable group;
• Q is an acceptor group individually selected from the group consisting of CH.sub.2 .dbd.CR.sup.1 COR.sup.2 --, CH.sub.2 .dbd.CR.sup.1 COOR.sup.2 --, CH.sub.2 .dbd.CR.sup.1 CONHR.sup.2 -- and CH.sub.2 .dbd.CR.sup.1 CR.sup.1 .dbd.CR.sup.2 --, where R.sup.1 is individually selected from the group consisting of hydrogen and monovalent, aliphatic hydrocarbon radicals having from 1 to 15 carbon atoms and R.sup.2 is individually selected from the group consisting of divalent hydrocarbon radicals having from 2 to 15 carbon atoms;
• x and x' are each positive integers from 0 to 3;
• y and y' are each positive integers from 0 to 3;
• z and z' are each positive integers from 0 to 3;
• x+y+z=3;
• x'+y'+z'=3;
• a is a positive integer from 0 to 10,000;
• b is a positive integer from 0 to 10,000;
• c is a positive integer from 0 to 20,000;
• d is a positive integer from 0 to 10,000;
• e is a positive integer from 0 to 10,000;
• provided, a+b+c.gtoreq.100 or d+e>3, and provided further, that there are at least 2 acceptor groups per organosiloxane polymer molecule;
• (B) a continuous water phase;
• (C) a surfactant;
• and
• (D) an effective amount of a crosslinker having sufficient reactive hydrogens per crosslinker molecule or a precursor thereto, the reactive hydrogens being covalently bonded to a nitrogen or sulfur atom of a donor group individually selected from the group consisting of --SH, --NH.sub.2 and --NHR.sup.3, where R.sup.3 is individually selected from the group consisting of monovalent hydrocarbon radicals having from 1 to 15 carbon atoms, the crosslinker being present in the continuous water phase or as a second dispersed phase separate from the dispersed phase containing the organosiloxane polymer, yielding a cured composition upon the removal of water.

A method of preparing an aqueous silicone emulsion which crosslinks by a Michael addition reaction, yielding a cured composition upon removal of water, comprising:

• (A) a dispersed phase comprising an organosiloxane polymer having the general formula ##STR5## where R is individually selected from the group consisting of hydrogen, 3,3,3-trifluoropropyl radicals and monovalent hydrocarbon radicals having from 1 to 15 carbon atoms;
• L is individually selected from the group consisting of hydrogen, a hydroxyl group, and a hydrolyzable group;
• Q is an acceptor group individually selected from the group consisting of CH.sub.2 .dbd.CR.sup.1 COR.sup.2 --, CH.sub.2 .dbd.CR.sup.1 COOR.sup.2 --, CH.sub.2 .dbd.CR.sup.1 ONHR.sup.2 -- and CH.sub.2 .dbd.CR.sup.1 CR.sup.1 .dbd.CR.sup.2 --, where R.sup.1 is individually selected from the group consisting of hydrogen and monovalent, aliphatic hydrocarbon radicals having from 1 to 15 carbon atoms and R.sup.2 is individually selected from the group consisting of divalent hydrocarbon radicals having from 2 to 15 carbon atoms;
• x and x' are each positive integers from 0 to 3;
• y and y' are each positive integers from 0 to 3;
• z and z' are each positive integers from 0 to 3;
• x+y+z=3;
• x'+y'+z'=3;
• a is a positive integer from 0 to 10,000;
• b is a positive integer from 0 to 10,000;
• c is a positive integer from 0 to 20,000;
• d is a positive integer from 0 to 10,000;
• e is a positive integer from 0 to 10,000;
• provided, a+b+c.gtoreq.100 or d+e>3, and provided further, that there are at least 2 acceptor groups per organosiloxane polymer molecule;
• (B) a continuous water phase;
• (C) a surfactant;
• and
• (D) an effective amount of a crosslinker having sufficient reactive hydrogens per crosslinker molecule or a precursor thereto, the reactive hydrogens being covalently bonded to a nitrogen or sulfur atom of a donor group individually selected from the group consisting of --SH, --NH.sub.2 and --NHR.sup.3 where R.sup.3 is individually selected from the group consisting of monovalent hydrocarbon radicals having from 1 to 15 carbon atoms, the crosslinker being present in the continuous water phase or as a second dispersed phase separate from the dispersed phase containing the organosiloxane polymer, yielding a cured composition upon the removal of water.