Methods for making unmodified polyvinyl alcohol films

Abstract

This invention relates, in general, to blend compositions of an unmodified poly vinyl alcohol and a thermoplastic elastomer and thermoplastic film and fiber structures comprising these blend compositions. More specifically, this invention relates to substantially water-free films and fibers comprising unmodified polyvinyl alcohol and a thermoplastic elastomer.

We claim:  
     
         1 . A substantially water-free thermoplastic article comprising from about 1 to about 99% by weight of an unmodified polyvinyl alcohol and from about 99 to about 1% by weight of a thermoplastic elastomer.  
     
     
         2 . The thermoplastic article of  claim 1 , wherein a 4% in water solution of the unmodified polyvinyl alcohol at 20° C. has a viscosity of less than about 20 centipoise.  
     
     
         3 . The thermoplastic article of  claim 2 , wherein a 4% in water solution of the unmodified polyvinyl alcohol at 20° C. has a viscosity of less than about 10 centipoise.  
     
     
         4 . The thermoplastic article of  claim 1 , wherein the unmodified polyvinyl alcohol has a hydrolysis of less than about 95%.  
     
     
         5 . The thermoplastic article of  claim 4 , wherein the unmodified polyvinyl alcohol has a hydrolysis of less than about 90%.  
     
     
         6 . The thermoplastic article of  claim 1 , wherein the unmodified polyvinyl alcohol has a weight-average molecular weight of less than about 140,000.  
     
     
         7 . The thermoplastic article of  claim 6 , wherein the unmodified polyvinyl alcohol has a weight-average molecular weight of less than about 60,000.  
     
     
         8 . The thermoplastic article of  claim 1 , wherein the unmodified polyvinyl alcohol has a melt viscosity at a shear rate of 500 s −1  of less than about 1500 Pa·s.  
     
     
         9 . The thermoplastic article of  claim 1 , wherein the thermoplastic article has less than about 2.0 percent by weight of water.  
     
     
         10 . The thermoplastic article of  claim 1 , wherein the thermoplastic article has less than about 1.0 percent by weight of water.  
     
     
         11 . The thermoplastic article of  claim 1 , wherein the thermoplastic article has less than about 0.5 percent by weight of water.  
     
     
         12 . The thermoplastic article of  claim 1 , wherein the thermoplastic elastomer is selected from polystyrene-polybutadiene-polystyrene block polymer, polystyrene-polyisoprene-polystyrene block polymer, polystyrene-poly(ethylene-butylene)-polystyrene block polymer, polystyrene-poly(ethylene-propylene)-polystyrene block polymer, elastomeric polyurethanes, ethylene-octene copolymers, polyester polyurethane, natural rubber, nitrile rubber, butyl rubber, ethylene-propylene terpolymers, silicone rubber, polyurethane rubber, thermoplastic rubbers, elastomeric block copolymers, copolymers of polyethylene oxide and polybutylene terephthalate, polyamide-polyether block copolymers, styrenic block copolymers, elastomeric polypropylene, or mixtures thereof.  
     
     
         13 . The thermoplastic article of  claim 1 , wherein the thermoplastic article comprises from about 50 to about 90% by weight of an unmodified polyvinyl alcohol and from about 50 to about 10% by weight of a thermoplastic elastomer.  
     
     
         14 . The thermoplastic article of  claim 1 , wherein the thermoplastic article comprises from about 65 to about 80% by weight of an unmodified polyvinyl alcohol and from about 35 to about 20% by weight of a thermoplastic elastomer.  
     
     
         15 . The thermoplastic article of  claim 1 , wherein the thermoplastic article is a film.  
     
     
         16 . The thermoplastic article of  claim 1 , wherein the thermoplastic article is a fiber.  
     
     
         17 . A thermoplastic article comprising from about 1 to about 99% by weight of an unmodified polyvinyl alcohol and from about 99 to about 1% by weight of a thermoplastic elastomer, wherein the thermoplastic article has less than about 2.0 percent by weight of water.  
     
     
         18 . The thermoplastic article of  claim 17 , wherein a 4% in water solution of the unmodified polyvinyl alcohol at 20° C. has a viscosity of less than about 20 centipoise.  
     
     
         19 . The thermoplastic article of  claim 18 , wherein a 4% in water solution of the unmodified polyvinyl alcohol at 20° C. has a viscosity of less than about 10 centipoise.  
     
     
         20 . The thermoplastic article of  claim 17 , wherein the unmodified polyvinyl alcohol has a hydrolysis of less than about 95%.  
     
     
         21 . The thermoplastic article of  claim 20 , wherein the unmodified polyvinyl alcohol has a hydrolysis of less than about 90%.  
     
     
         22 . The thermoplastic article of  claim 17 , wherein the unmodified polyvinyl alcohol has a weight-average molecular weight of less than about 140,000.  
     
     
         23 . The thermoplastic article of  claim 22 , wherein the unmodified polyvinyl alcohol has a weight-average molecular weight of less than about 60,000.  
     
     
         24 . The thermoplastic article of  claim 17 , wherein the unmodified polyvinyl alcohol has a melt viscosity at a shear rate of 500 s −1  of less than about 1500 Pa·s.  
     
     
         25 . The thermoplastic article of  claim 17 , wherein the thermoplastic elastomer is selected from polystyrene-polybutadiene-polystyrene block polymer, polystyrene-polyisoprene-polystyrene block polymer, polystyrene-poly(ethylene-butylene)-polystyrene block polymer, polystyrene-poly(ethylene-propylene)-polystyrene block polymer, elastomeric polyurethanes, ethylene-octene copolymers, polyester polyurethane, natural rubber, nitrile rubber, butyl rubber, ethylene-propylene terpolymers, silicone rubber, polyurethane rubber, thermoplastic rubbers, elastomeric block copolymers, copolymers of polyethylene oxide and polybutylene terephthalate, polyamide-polyether block copolymers, styrenic block copolymers, elastomeric polypropylene, or mixtures thereof.  
     
     
         26 . The thermoplastic article of  claim 17 , wherein the thermoplastic article comprises from about 50 to about 90% by weight of an unmodified polyvinyl alcohol and from about 50 to about 10% by weight of a thermoplastic elastomer.  
     
     
         27 . The thermoplastic article of  claim 17 , wherein the thermoplastic article comprises from about 65 to about 80% by weight of an unmodified polyvinyl alcohol and from about 35 to about 20% by weight of a thermoplastic elastomer.  
     
     
         28 . The thermoplastic article of  claim 17 , wherein the thermoplastic article is a film.  
     
     
         29 . The thermoplastic article of  claim 17 , wherein the thermoplastic article is a fiber.  
     
     
         30 . A substantially water-free blend composition comprising from about 1 to about 99% by weight of an unmodified polyvinyl alcohol and from about 99 to about 1% by weight of a thermoplastic elastomer.  
     
     
         31 . A personal care article comprising the composition of  claim 1 .  
     
     
         32 . The personal care article of  claim 31 , wherein the personal care article is a diaper.  
     
     
         33 . The personal care article of  claim 31 , wherein the personal care article is a feminine pad.  
     
     
         34 . The personal care article of  claim 31 , wherein the personal care article are training pants.  
     
     
         35 . The personal care article of  claim 31 , wherein the personal care article is an adult incontinence product.