Hydrophilic polypropylene fibers having antimicrobial activity

Abstract

Polypropylene fibers and devices that include a fatty acid monoglyceride added to the polypropylene as a melt additive are described. A hydrophilic enhancer material can be advantageously added to the polypropylene as a melt additive to enhance the hydrophilicity of the fibers and devices. An antimicrobial enhancer material can be added to the fibers to enhance the antimicrobial activity.

1 . An absorbent device comprising:
 an absorbent layer comprising hydrophilic polypropylene fibers having incorporated therein a C 8  to C 16  fatty acid monoglyceride and a hydrophilic enhancer material.   
     
     
         2 . The absorbent device of  claim 1  wherein the monoglyceride is selected from the group consisting of glycerol monocaprylate, glycerol monocaprate, and glycerol monolaurate. 
     
     
         3 . The absorbent device of  claim 1  wherein the hydrophilic enhancer material is incorporated prior to fiber formation in an amount from about 2 to about 25 weight percent. 
     
     
         4 . The absorbent device of  claim 1  wherein the hydrophilic enhancer material is selected from the group consisting of polybutylene, polybutylene copolymers ethylene/octene copolymers, and atactic polypropylene. 
     
     
         5 . The absorbent device of  claim 1  wherein the hydrophilic enhancer material is selected from the group consisting of sorbitan monolaurate and sorbitan monopalmitate. 
     
     
         6 . The absorbent device of  claim 1  wherein the hydrophilic enhancer material is a mixture of a polybutylene and a sorbitan monolaurate. 
     
     
         7 . The absorbent device of  claim 1  wherein the monoglyceride is a C 8  to C 12  fatty acid monoglyceride. 
     
     
         8 . The absorbent device of  claim 1  wherein the surface of the fibers is treated with an effective amount of an antimicrobial enhancer material such that the fiber is antimicrobial to Gram-negative bacteria. 
     
     
         9 . The absorbent device of  claim 8  wherein the antimicrobial enhancer material is selected from the group consisting of organic acids and chelating agents. 
     
     
         10 . The absorbent device of  claim 1 , wherein the absorbent layer absorbs greater than 900% as measured by the Percent Water Absorbency Test. 
     
     
         11 . The absorbent device of  claim 1 , further comprising an absorbent additive. 
     
     
         12 . The absorbent device of  claim 1 , wherein the absorbent additive is selected from the group consisting of wood pulp, cellulose, cotton, rayon, recycled cellulose, shredded cellulose sponge, and mixtures thereof. 
     
     
         13 . The absorbent device of  claim 1 , wherein the thickness of the absorbent layer is from about 0.5 to about 10 mm. 
     
     
         14 . An absorbent device comprising:
 an absorbent layer comprising hydrophilic polypropylene fibers having incorporated therein an effective amount of a C 12  fatty acid monoglyceride such that the fiber is hydrophilic, and an effective amount of an antimicrobial enhancer material, wherein the fiber is antimicrobial to Gram-positive bacteria and to Gram-negative bacteria.   
     
     
         15 . The absorbent device of  claim 14  wherein the polypropylene fibers additionally have incorporated therein a hydrophilic enhancer material. 
     
     
         16 . The absorbent device of  claim 15  wherein the hydrophilic enhancer material is a selected from the group consisting of polybutylene, polybutylene copolymers ethylene/octene copolymers, and atactic polypropylene. 
     
     
         17 . The absorbent device of  claim 14  wherein the monoglyceride is a C 8  to C 12  fatty acid monoglyceride. 
     
     
         18 . The absorbent device of  claim 14  wherein the antimicrobial enhancer material is selected from the group consisting of organic acids and chelating agents. 
     
     
         19 . The absorbent device of  claim 14 , wherein the absorbent layer absorbs greater than 900% as measured by the Percent Water Absorbency Test. 
     
     
         20 . The absorbent device of  claim 14 , further comprising an absorbent additive. 
     
     
         21 . The absorbent device of  claim 20 , wherein the absorbent additive is selected from the group consisting of wood pulp, cellulose, cotton, rayon, recycled cellulose, shredded cellulose sponge, and mixtures thereof. 
     
     
         22 . The absorbent device of  claim 14 , wherein the thickness of the absorbent layer is from about 0.5 to about 10 mm. 
     
     
         23 . An absorbent device comprising:
 (a) an absorbent layer comprising (i) hydrophilic polypropylene fibers having incorporated therein an effective amount of a glycerol monolaurate, and the surface of the fiber is covered by a dry coating containing an effective amount of lactic acid, wherein the fiber is antimicrobial to Gram-positive bacteria and to Gram-negative bacteria, and (ii) an absorbent additive;   (b) a liquid-impermeable and moisture vapor-permeable backing sheet adhered to an outer surface of the absorbent layer.   
     
     
         24 . The absorbent device of  claim 23  further comprising a hydrophilic enhancer material incorporated into the fibers, the hydrophilic enhancer material being selected from the group consisting of a polybutylene, a polybutylene copolymer, a sorbitan monolaurate, a sorbitan monopalmitate, and mixtures thereof. 
     
     
         25 . The absorbent device of  claim 23 , wherein the absorbent additive is selected from the group consisting of wood pulp, cellulose, cotton, rayon, recycled cellulose, shredded cellulose sponge, and mixtures thereof. 
     
     
         26 . A fibrous nonwoven, woven or knit web or batt, the web or batt comprising hydrophilic polypropylene fibers having incorporated therein a C 8  to C 16  fatty acid monoglyceride and a hydrophilic enhancer material. 
     
     
         27 . The web or batt of  claim 26  wherein the monoglyceride is selected from the group consisting of glycerol monocaprylate, glycerol monocaprate, and glycerol monolaurate. 
     
     
         28 . The web or batt of  claim 26  wherein the hydrophilic enhancer material is incorporated prior to fiber formation in an amount from about 2 to about 25 weight percent. 
     
     
         29 . The web or batt of  claim 26  wherein the hydrophilic enhancer material is selected from the group consisting of polybutylene, polybutylene copolymers ethylene/octene copolymers, and atactic polypropylene. 
     
     
         30 . The web or batt of  claim 26  wherein the surface of the fibers is treated with an effective amount of an antimicrobial enhancer material such that the fiber is antimicrobial to Gram-negative bacteria. 
     
     
         31 . A fibrous nonwoven, woven or knit web or batt, the web or batt comprising hydrophilic polypropylene fibers having incorporated therein an effective amount of a C 12  fatty acid monoglyceride such that the fiber is hydrophilic, and an effective amount of an antimicrobial enhancer material, wherein the fiber is antimicrobial to Gram-positive bacteria and to Gram-negative bacteria. 
     
     
         32 . The web or batt of  claim 31  wherein the polypropylene fibers additionally have incorporated therein a hydrophilic enhancer material. 
     
     
         33 . The web or batt of  claim 32  wherein the hydrophilic enhancer material is a selected from the group consisting of polybutylene, polybutylene copolymers ethylene/octene copolymers, and atactic polypropylene. 
     
     
         34 . A method of preparing hydrophilic fibers comprising:
 (a) preparing a hot melt mixture comprising melted polypropylene and sufficient amounts of (i) at least one C 8  to C 16  fatty acid monoglyceride and (ii) a hydrophilic enhancer material that are effective to impart hydrophilicity to the fibers; and   (b) extruding the mixture into fibers.   
     
     
         35 . The method of  claim 34  wherein the hydrophilic enhancer material is selected from the group consisting of a polybutylene, a polybutylene copolymer, a sorbitan monolaurate, and mixtures thereof. 
     
     
         36 . The method of  claim 34  wherein the monoglyceride is a glycerol monolaurate. 
     
     
         37 . A method of preparing fibers that are both hydrophilic and antimicrobial to Gram-positive and Gram-negative bacteria, comprising:
 (a) preparing a hot melt mixture comprising melted polypropylene and an amount of at least one C 8  to C 12  fatty acid monoglyceride that is effective to impart both hydrophilicity and antimicrobial activity to Gram-positive bacteria to the surface of the fiber;   (b) extruding the mixture into fibers;   (c) contacting the fibers with a liquid composition comprising at least one antimicrobial enhancer material, thereby cooling and at least partially solidifying the fibers to yield an essentially dry coating of the antimicrobial enhancer material on the surface of the fibers that is of sufficient concentration and uniformity such that the fiber surface is antimicrobial to Gram-negative bacteria.   
     
     
         38 . The method of  claim 37  further comprising incorporating an effective amount of a hydrophilic enhancer material in the polypropylene to enhance the hydrophilicity of the fibers. 
     
     
         39 . The method of  claim 38  wherein the hydrophilic enhancer material is selected from the group consisting of a polybutylene, a polybutylene copolymer, a sorbitan monolaurate, a sorbitan monopalmitate, and mixtures thereof. 
     
     
         40 . The method of  claim 37  wherein the monoglyceride is a glycerol monolaurate. 
     
     
         41 . The method of  claim 38  wherein the hydrophilic enhancer material is a sorbitan monolaurate and the antimicrobial enhancer material is an organic acid or a chelating agent. 
     
     
         42 . The method of  claim 37  wherein the antimicrobial enhancer material is a lactic acid.