초록 ▼

Described herein are methods of preparing PUD based, poromeric, synthetic leathers having improved embossing characteristics, the methods comprising: preparing a polyurethane prepolymer, wherein the prepolymer comprises at least one isocyanate resin, and at least two polyols; preparing a first mixtu

Described herein are methods of preparing PUD based, poromeric, synthetic leathers having improved embossing characteristics, the methods comprising: preparing a polyurethane prepolymer, wherein the prepolymer comprises at least one isocyanate resin, and at least two polyols; preparing a first mixture comprising the polyurethane prepolymer, water, a chain extender, and a first surfactant that comprises at least one surfactant; preparing a second mixture comprising the first mixture, a thickening agent, and a second surfactant the comprises at least one surfactant, frothing the second mixture and thereby forming a frothed second mixture; applying the frothed second mixture to a fabric and thereby forming a coated fabric; optionally adjusting the thickness of the frothed third mixture on the fabric; and drying the coated fabric.

대표청구항 ▼

1. Methods of preparing poromeric synthetic leathers having improved embossing characteristics, the methods comprising: preparing a polyurethane prepolymer by reacting a mixture comprising, at least one isocyanate resin, and at least two polyols;mixing said polyurethane prepolymer, with water, at le

1. Methods of preparing poromeric synthetic leathers having improved embossing characteristics, the methods comprising: preparing a polyurethane prepolymer by reacting a mixture comprising, at least one isocyanate resin, and at least two polyols;mixing said polyurethane prepolymer, with water, at least one surfactant and other optional additives to form a first mixture;adding at least one chain extender to the first mixture to form a polyurethane/urea dispersion (PUD) having urea to urethane ratio of 0.9 to 0.06;preparing a second mixture comprising the PUD, at least one thickening agent, and at least one surfactant;frothing the second mixture and thereby forming a frothed second mixture;applying the frothed second mixture to a fabric and thereby forming a coated fabric;optionally adjusting the thickness of the frothed second mixture on the fabric; anddrying the coated fabric. 2. (canceled) 3. Methods according to claim 1, wherein at least one of the two polyols is a polyether polyol having an averang molecular weight of 400 to 1500 g/mol. 4. (canceled) 5. Methods according to claim 1, wherein at least one of the two polyols is Methoxy Polyethylene Glycol (MPEG). 6. Methods according to claim 1, wherein the polyurethane prepolymer is made by combining a liquid isocyanate resin and at least two liquid polyols. 7. (canceled) 8. Methods according to claim 1, wherein preparing the polyurethane prepolymer comprises melting the isocyanate resin, heating the at least one polyol and then combining the melted isocyanate resin and the heated at least one polyol. 9. Methods according to claim 1, wherein the polyurethane prepolymer comprises at least three polyols. 10. (canceled) 11. Method according to claim 9, wherein one of the at least three polyols is polypropylene glycol. 12. Methods according to claim 1, wherein the isocyanate comprises diisocyanatodiphenylmethane (MDI). 13. Methods according to claim 1, wherein the solid content of the first mixture is 45-65%. 14. Methods according to claim 1. wherein the polyurethane prepolymer contains less than five polyols and the chain extender comprises at least two amine groups. 15. Methods according to claim 1, wherein at least one isocyanate resin is methylenediphenyl diisocyanate, and wherein the chain extender comprises water, aminoethylethanolamine, or combinations thereof. 16. Methods according to claim 1, wherein in the polyurethane prepolymer, the ratio of the polyols to the isocyanate is from 1:1 to 4:1. 17. Methods according to claim 1, wherein the ratio of the first surfactant to the polyurethane prepolymer is from 1:5 to 0.01:5. 18. Methods according to claim 1, wherein each polyol has an average molecular weight of less than 2000 g/mol. 19. Methods according to claim 1, comprising melting 4,4′- methylenediphenyl diisocyanate;preparing a polyol mixture comprising at least two polyols, wherein at least one polyol is a polyether polyol;heating the mixture of at least two polyols to a temperature of at least 30° C. (preferably, 30-60° C.);optionally adding a base scavenger to said polyol mixture;preparing a polyurethane prepolymer by reacting a mixture comprising the melted diisocyanate, the heated polyol mixture and the optional base scavenger;mixing said polyurethane prepolymer with water, at least one surfactant, and water, to form a first mixture;adding at least one chain extender to the first mixture to form a polyurethane dispersion (PUD) having urea to urethane ratio of 0.9 to 0.06;mixing the PUD;preparing a second mixture comprising the PUD, at least two surfactants, and a thickener;frothing the second mixture and thereby forming a frothed second mixture;applying the frothed second mixture to a fabric and thereby forming a coated fabric;optionally adjusting the thickness of the frothed second mixture on the fabric; anddrying the coated fabric. 20. (canceled) 21. Poromeric, synthetic leathers having improved embossing characteristics made according to claim 1.