Polyurethane based synthetic leathers comprising nanoparticles and having improved peel strength

Abstract

Disclosed herein are methods of producing externally stabilized, poromeric synthetic leathers having improved peel strength, the methods comprising: preparing a prepolymer from a mixture comprising at least one polyester polyol, at least one polyether polyol, at least one isocyanate and optionally in a solvent; mixing the prepolymer, water, and a first surfactant; optionally add a second chain extender to form a PUD; preparing a mixture comprising said PUD, at least one surfactant, and at least one thickener; frothing said mixture; applying the frothed mixture to a fabric and thereby forming a coated fabric; adjusting the thickness of the frothed mixture on the coated fabric; drying the coated fabric. Methods of improving the peel strength of poromeric synthetic leathers are also disclosed. Externally stabilized synthetic leathers having improved peel strength are also disclosed.

What is claimed is: 
     
         1 . Methods for producing externally stabilized, poromeric synthetic leathers having improved peel strength, the methods comprising:
 preparing a prepolymer from a mixture comprising at least one polyester polyol, at least one polyether polyol, at least one isocyanate and optionally in a solvent;   mixing the prepolymer, water, and a first surfactant;   optionally add a second chain extender to form a PUD;   preparing a mixture comprising said PUD, at least one surfactant, and at least one thickener;   frothing said mixture;   applying the frothed mixture to a fabric and thereby forming a coated fabric;   adjusting the thickness of the frothed mixture on the coated fabric;   drying the coated fabric.   
     
     
         2 . Methods of improving the peel strength of poromeric synthetic leathers, the methods comprising:
 preparing a prepolymer from a mixture comprising at least one polyester polyol, at least one polyether polyol, at least one isocyanate and optionally in a solvent;   mixing the prepolymer, water, and a first surfactant;   optionally add a second chain extender to form a PUD;   preparing a mixture comprising said PUD, at least one surfactant, and at least one thickener;   frothing said mixture;   applying the frothed mixture to a fabric and thereby forming a coated fabric;   adjusting the thickness of the frothed mixture on the coated fabric;   drying the coated fabric.   
     
     
         3 . Methods according to  claim 1 , wherein the fabric is a needled cotton and polyester fiber hybrid woven fabric having short fibers on the surface and is optionally impregnated with a polymer resin. 
     
     
         4 . Methods according to  claim 1 , wherein at least one surfactant is ammonium stearate, disodium octadecyl sulfosuccinimate or cocamidopropyl betaine. 
     
     
         5 . Methods according to  claim 1 , wherein the mixture comprises at least two surfactants. 
     
     
         6 . Methods according to  claim 1 , wherein the mixture further comprises at least one additive that is CaCO 3 , SiO 2 , wood fibers, TiO 2 , a flame retardant, a pigment, a flowing additive, handfeel additive, antioxidant, anti-UV additive, or combinations thereof. 
     
     
         7 . Methods according to  claim 1 , wherein the PUD has a solid content of 30-65% by weight. 
     
     
         8 . Methods according to  claim 1 , wherein the isocyanate comprises isophorone diisocyanate; 4,4′-diisocyanatodiphenylmethane; 2,4′-diisocyanatodiphenylmethane, or combinations thereof. 
     
     
         9 . Methods according to  claim 1 , wherein the polyester:polyether ratio in the PUD is 1:0.5-4. 
     
     
         10 . Methods according to  claim 1 , wherein the coated fabric is dried/cured at a temperature of at least 30° C. and no more than 200° C. 
     
     
         11 . Methods according to  claim 1 , wherein the isocyanate comprised methylenediphenyl diisocyanate, and at least one polyester polyol has an Mn of 1000-2000. 
     
     
         12 . Methods according to  claim 1 , wherein the thickening agent is an acrylic acid copolymer. 
     
     
         13 . Methods according to  claim 1 , wherein the PUD is mixed with at least three surfactants that are independently selected from the group consisting of disodium octadecyl sulfosuccinimate, sodium dodecylbenzene sulfonate, sodium alpha olefin sulfonate, sodium stearate, cocamidopropyl betaine, and ammonium stearate. 
     
     
         14 . Methods according to  claim 13 , wherein the at least three surfactants are ammonium stearate, disodium octadecyl sulfosuccinimate and cocamidopropyl betaine, and are in the ratio of 1:0.2-0.4:0.23-0.4. 
     
     
         15 . A porometric synthetic leather made according to  claim 15 .