Aqueous dispersions of polyureaurethanes
Stable aqueous poly(urea/urethane) polymers and dispersions are made that do not require the inclusion of chain extenders, curing agents or crosslinking agents.
1 . A urea/urethane polymer comprising (a) repeating units derived from a hydroxy-terminated copolymer prepared from tetrahydrofuran and one or both of an alkylene oxide and a cyclic acetal, and (b) repeating units derived from a polyisocyanate;
wherein the urea/urethane polymer contains less than about 2 mole percent of urea units described by the formula —R—N(R 2 )—C(O)—N(R 2 )—R 1 —;
wherein R is an aromatic hydrocarbon radical, R 1 is an aliphatic hydrocarbon radical, and R 2 is H or an amide group that is described by the formula —C(O)—N(R 2 )—R—; and
wherein the tetrahydrofuran is described by the formula
in which any one of the R 4 s may be a C 1 to C 4 alkyl radical with the remaining R 4 s being hydrogen.
2 . A urea/urethane polymer according to claim 1 wherein the polyisocyanate is selected from the group consisting of toluene diisocyanate, methylene diphenyldiisocyanate and polymethylene polyphenylisocyanate.
3 . A urea/urethane polymer according to claim 1 wherein the alkylene oxide is selected from the group consisting of 1,2-propylene oxide and ethylene oxide.
4 . A urea/urethane polymer according to claim 1 wherein the alkylene oxide is ethylene oxide.
5 . A urea/urethane polymer according to claim 1 wherein each R 4 in the tetrahydrofuran is hydrogen.
6 . A urea/urethane polymer according to claim 1 wherein each R 4 in the tetrahydrofuran is hydrogen, the hydroxy-terminated copolymer is prepared from an alkylene oxide, and the alkylene oxide is ethylene oxide.
7 . A urea/urethane polymer according to claim 1 wherein the urea/urethane polymer contains less than about 1 mole percent of the described urea units.
8 . A urea/urethane polymer according to claim 1 wherein the urethane polymer further comprises repeating units derived from an ionic compound or a potentially ionic compound.
9 . An aqueous dispersion of a urea/urethane polymer wherein the urea/urethane polymer comprises a polymer according to claim 1 and a surfactant.
10 . An ionomeric urea/urethane polymer comprising (a) repeating units derived from an aliphatic polyether polyol having a molecular weight of about 700 to about 1500, and (b) repeating units derived from a polyisocyanate,
wherein the urea/urethane polymer contains less than about 2 mole percent of urea units described by the formula —R—N(R 2 )—C(O)—N(R 2 )—R 1 —;
wherein R is an aromatic C 6 -C 20 hydrocarbon radical, R 1 is an aliphatic C 1 -C 20 hydrocarbon radical, and R 2 is H or an amide group that is described by the formula —C(O)—N(R 2 )—R—.
11 . A urea/urethane polymer according to claim 10 which comprises repeating units derived from an ionic compound or a potentially ionic compound.
12 . A urea/urethane polymer according to claim 11 wherein the ionic compound or potentially ionic compound comprises a hydroxy-carboxylic acid of the general formula (HO) x R 7 (COOH) y , wherein R 7 represents a straight or branched hydrocarbon radical containing 1 to 12 carbon atoms, and x and y each independently represents values from 1 to 3.
13 . A urea/urethane polymer according to claim 11 wherein the ionic compound or potentially ionic compound comprises 2,2′ dimethanolpropionic acid.
14 . A urea/urethane polymer according to claim 10 wherein the polyisocyanate is selected from the group consisting of toluene diisocyanate, methylene diphenyldiisocyanate and polymethylene polyphenylisocyanate.
15 . A urea/urethane polymer according to claim 10 wherein the polyether polyol is described by the formula HO—[(CR 5 H) m —O—] n —H, wherein R 5 is hydrogen, a halogen or a C 1 to C 4 alkyl radical; m is 3 or 4; and n is in the range of about 8 to about 20.
16 . A urea/urethane polymer according to claim 15 wherein R 5 is hydrogen.
17 . A urea/urethane polymer according to claim 10 wherein the polyether polyol has a molecular weight in the range of about 900 to about 1150.
18 . A urea/urethane polymer according to claim 10 wherein the urea/urethane polymer contains less than about 1 mole percent of the described urea units.
19 . An aqueous dispersion of a urea/urethane polymer wherein the urea/urethane polymer comprises a polymer according to claim 10 and a surfactant.