Polyurethane-urea polymers derived from cyclohexane dimethanol
Aqueous polyurethane dispersion are disclosed where the dispersions contain from 5 to 70 weight percent polyurethane solids wherein the solids are obtained from at least one isocyanate terminated prepolymer prepared by reacting (a) a polyol or polyol blend having a mean average equivalent weight of 200 to 2,000; and (b) at least one polyisocyanate where the prepolymer is dispersed in water; optionally in the presence of (c) one or more stabilizers; or (d) one or more amine chain extenders or both; wherein the prepolymers have an isocyanate (NCO) content of from 2 to 40 weight percent and the polyol or polyol blend (a) contains at least 15 weight percent of a polyester based on a polycarboxylic acid or lactone component and a glycol component, wherein the glycol component contains isomers of 1,3- and 1,4-cyclohexanedimethanol (1,3-/1,4-CHDM) where the ratio of the 1,3-/1,4-isomers is from 35:65 to 65:35.
1. An aqueous polyurethane dispersion containing from 5 to 70 weight percent polyurethane solids wherein the solids are obtained from at least one isocyanate terminated prepolymer prepared by reacting
(a) a polyol or polyol blend having a mean average equivalent weight of 200 to 2,000; and
(b) at least one polyisocyanate where the prepolymer is dispersed in water; optionally in the presence of
(c) 0.01 to 8 parts by weight of the polyurethane of one or more surfactants; and
(d) one or more amine chain extenders;
wherein the prepolymers have an isocyanate content of from 2 to 40 weight percent and the polyol or polyol blend (a) contains at least 15 weight percent of a polyester based on a C2 to C12 polycarboxylic acid and a glycol component, wherein the glycol component contains isomers of 1,3- and 1,4-cyclohexanedimethanol where the ratio of the 1,3-/1,4-isomers is from 35:65 to 65:35.
2. The dispersion of claim 1 wherein the solids content is from 40 to 60 weight percent.
3. The dispersion of claims 1 wherein the polyisocyanate is an aliphatic isocyanate.
4. The dispersion of claim 3 wherein the isocyanate is 1,6-hexamethylene-diisocyanate; isophorone diisocyanate, 1,3-, 1,4-bis(isocyanatomethyl)cyclohexane or a mixture thereof.
5. The dispersion of claim 1 wherein the polyisocyanate is an aromatic isocyanate.
6. The dispersion of claim 5 wherein the isocyanate is 2,4- or 2,-6 -toluenediisocyanate, 4,4′, 2,4′ or 2,2′-diphenylmethanediisocyanate or a mixture of such isomers, polyphenyl polymethylene polyisocyanate or a mixture thereof.
7. The dispersion of claim 6 wherein the isocyanate is diphenylmethanediisocyanate.
8. The dispersion of claim 1 wherein the prepolymer and dispersion are prepared in the absence of an organic solvent.
9. The dispersion of any one of the preceding claims wherein the polyol or polyol blend has an average mean equivalent weight of 300 to 1500.
10. This dispersion of claim 9 wherein the polyol or polyol blend has an average mean equivalent weight of 400 to 1200.
11. The dispersion of claim 1 wherein the polyester based on 1,3,-/1,4-cyclohexanedimethanol comprises at least 50 weight percent of the total polyol component.
12. The dispersion of claim 1 wherein the prepolymer is made in the presence of a solvent and the solvent is substantially removed prior to dispersion of the prepolymer in water.
13. The dispersion of any of the preceding claims wherein the dispersion is made in a continuous process.
14. A polyurethane polymer derived from the dispersion of claim 1 .
15. The polymer of claim 14 wherein the polyurethane polymer is a coating, adhesive, sealant, elastomer or foam.