Integral composite wax-polymer membranes

Abstract

A composite barrier membrane coated on a substrate and membrane is formed by phase inversion technique utilizing a water-insoluble wax and a water-insoluble polymer dissolved in a solvent. The barrier membrane coated upon the substrate is used to control transmembrane transport of a liquid and a gas. The substrate can be a starch based food package material, a protein based food package materials, a natural fabric, a synthetic fabric, or a paper product.

What is claimed is:  
     
         1 . A device comprising a substrate having a composite membrane coated thereon, the composite membrane being fabricated from a composition, the composition comprising, based on the final weight of the composition: 
 a water-insoluble polymer, in an amount of from about 3% to about 50%; and    a water-insoluble wax, in an amount of from about 0.001% to about 20%;    in a solvent.    
     
     
         2 . The device of  claim 1 , wherein the substrate comprises a starch-based polymer product.  
     
     
         3 . The device of  claim 1 , wherein the substrate comprises a non-woven fabric.  
     
     
         4 . The device of  claim 1 , wherein the composition further comprises an ingredient selected from the group consisting of stearic acid, palmitic acid, and stearyl alcohol, in an amount of from about 0.01% to about 10%.  
     
     
         5 . The composition of  claim 1 , wherein the composite membrane is fabricated by phase inversion technique.  
     
     
         6 . The composition of  claim 1 , wherein the water-insoluble polymer is in an amount of from about of from about 3% to about 50%.  
     
     
         7 . The composition of  claim 1 , wherein the water-insoluble wax is in an amount of from about of from about 0.001% to about 20%.  
     
     
         8 . The composition of  claim 1 , wherein the water-insoluble polymer is selected from the group consisting of cellulose acetate butyrate, cellulose acetate propionate, cellulose acetate and ethylcellulose.  
     
     
         9 . The composition of  claim 1 , wherein the water-insoluble polymer is selected from the group consisting of polysulfone and polyacrylonitrile-co-butadiene-co-styrene.  
     
     
         10 . The composition of  claim 1 , wherein the water-insoluble wax is selected from the group consisting of beeswax, carnauba wax and cadelilla wax.  
     
     
         11 . The composition of  claim 1 , wherein the water-insoluble wax is selected from the group consisting of Callista 158, Shellwax 200 and Shellwax 300.  
     
     
         12 . The composition of  claim 1 , wherein the solvent is selected from the group consisting of dimethylformamide, dimethylacetamide and ethanol.  
     
     
         13 . The composition of  claim 1 , wherein the solvent is selected from the group consisting of acetone, butanone, chloroform, benzene, toluene and acetic acid.  
     
     
         14 . The composition of  claim 1 , wherein the solvent is phosphoric acid.  
     
     
         15 . A composition for fabricating a composite membrane used for coating a substrate, the composition comprising, based on the final weight of the composition: 
 a water-insoluble polymer, in an amount of from about 5% to about 30%; and    a water-insoluble wax, in an amount of from about 0.1% to about 10% having a melting point of from about 45° C. to about 120° C.; and    in a solvent.    
     
     
         16 . The composition of  claim 15 , wherein the composition further comprises an ingredient selected from the group consisting of stearic acid, palmitic acid and stearyl alcohol, in an amount of from about 0.05% to about 5%.  
     
     
         17 . The composition of  claim 15 , wherein the composite membrane is fabricated by phase inversion technique.  
     
     
         18 . The composition of  claim 15 , wherein the water-insoluble polymer is in an amount of from about of from about 8% to about 25%.  
     
     
         19 . The composition of  claim 15 , wherein the water-insoluble wax is in an amount of from about 0.2% to about 5% having a melting point of from about 50° C. to about 80° C.  
     
     
         20 . The composition of  claim 15 , wherein the water-insoluble polymer is selected from the group consisting of cellulose acetate butyrate, cellulose acetate propionate, cellulose acetate and ethylcellulose.  
     
     
         21 . The composition of  claim 15 , wherein the water-insoluble polymer is selected from the group consisting of polysulfone and polyacrylonitrile-co-butadiene-co-styrene.  
     
     
         22 . The composition of  claim 15 , wherein the water-insoluble wax is selected from the group consisting of beeswax, carnauba wax and cadelilla wax.  
     
     
         23 . The composition of  claim 15 , wherein the water-insoluble wax is selected from the group consisting of Callista 158, Shellwax 200 and Shellwax 300.  
     
     
         24 . The composition of  claim 15 , wherein the solvent is selected from the group consisting of dimethylformamide, dimethylacetamide and ethanol.  
     
     
         25 . The composition of  claim 15 , wherein the solvent is selected from the group consisting of acetone, butanone, chloroform, benzene, toluene and acetic acid.  
     
     
         26 . The composition of  claim 15 , wherein the solvent is phosphoric acid.  
     
     
         27 . A method for fabricating a composite membrane on a surface of a substrate, comprising: 
 dissolving a mixture of a water-insoluble polymer, a water-insoluble polymer in an organic solvent to give a solution;    removing air bubbles from the solution to give a final solution;    casting the final solution onto the surface of the substrate; and    curing the surface of the substrate having the final solution thereon to give a composite membrane on the surface of the substrate.    
     
     
         28 . The method of  claim 27 , wherein the substrate is selected from the group consisting of a starch based food package material, a protein based food package materials, a natural fabric, a synthetic fabric, and a paper product.  
     
     
         29 . A composition for fabricating a composite membrane used for coating a substrate, the composition comprising, based on the final weight of the composition: 
 from about 3% to about 7% of beeswax;    from about 10% to about 14% of cellulose acetate butyrate;    from about 0.6% to about 1% of 1-octadecanol; and    from about 80% to about 84% butanone.    
     
     
         30 . The composition of  claim 29 , wherein the substrate is selected from the group consisting of a starch based food package material, a protein based food package materials, a natural fabric, a synthetic fabric, and a paper product.  
     
     
         31 . A method for fabricating a composite membrane on a surface of a substrate, comprising, based on the final weight of the composition: 
 mixing from about 1% to about 5% of beeswax, from about 7% to about 11% of cellulose acetate butyrate, and from about 86% to about 90% of a 1 to 4 mixture of acetone and butanone to give a composition;    heating the composition to a temperature of from about 60° C. to about 70° C. for a period of from about 10 minutes to about 20 minutes to obtain a uniform solution;    keeping the uniform solution at a temperature of from about 60° C. to about 70° C. for a period of from about 1 to about 5 hours to give a solution relatively free of air bubbles;    applying the solution relatively free of air bubbles on the surface of the substrate to give a pre-coated substrate;    heating the pre-coated substrate to a temperature of from about 60° C. to about 75° C. for a period of from about 1 minute to about 10 minutes to give a heated substrate; and    cooling the heated substrate to give a coated substrate.    
     
     
         32 . The method of  claim 31 , further comprising heating the coated substrate to a temperature of from about 60° C. to about 75° C. for a period of from about 1 minute to about 7 minutes.  
     
     
         33 . The method of  claim 31 , wherein the substrate is selected from a group consisting of a starch based food package material, a protein based food package materials, a natural fabric, a synthetic fabric, and a paper product.  
     
     
         34 . A method for controlling transmembrane transport of a liquid or a gas through a composite membrane, the composite membrane being fabricated from a composition, the composition comprising, based on the final weight of the composition, a water-insoluble polymer, in an amount of from about 3% to about 50%, and a water-insoluble wax, in an amount of from about 0.001% to about 20%, dissolved in a solvent, the method comprising: 
 adjusting the ratio of the water-insoluble wax to the water-insoluble polymer in the composition.    
     
     
         35 . The method of  claim 34 , wherein the composite membrane is being coated on a substrate.  
     
     
         36 . The method of  claim 35 , wherein the substrate is selected from the group consisting of a starch based food package material, a protein based food package materials, a natural fabric, a synthetic fabric, and a paper product  
     
     
         37 . The method of  claim 35 , wherein the liquid comprises water.  
     
     
         38 . The method of  claim 35 , wherein the gas is selected from the group consisting of water vapor, nitrogen, and oxygen.