Non-woven fabric composites from coir fibers

Abstract

A non-woven fabric composite containing coir fibers and a method for producing such composites. The non-woven fabric composite is comprised of coir fibers, which are large diameter, lignin-rich fibers, with a high viscous flow temperature and a high degradation temperature combined with fibers made of a thermoplastic polymer with a lower viscous flow temperature such as polypropylene, polyethylene or a biodegradable thermoplastic polymer fiber such as polylactic acid, or mixture thereof. A hot-pressed non-woven fabric composite material prepared from the non-woven fabric composite.

1 . A non-woven fabric composite material, comprising:
 coir fiber; and   a fiber made from or including a synthetic thermoplastic polymer,   wherein the synthetic thermoplastic polymer is selected from the group consisting of polypropylene, polyethylene, polylactic acid, and mixtures thereof,   wherein the coir fiber and the fiber made from the synthetic thermoplastic polymer are matted together to form a matted material,   wherein the coir fiber has a higher viscous flow temperature and a higher degradation temperature than that of the fiber made from the synthetic thermoplastic polymer, and   wherein the matted material has been heated to a temperature throughout the matted material that is higher than the melt temperature of the fiber made from or including the synthetic thermoplastic polymer but less than the degradation temperature of the coir fiber and hot pressed at that temperature at a compression pressure range of 25 psi or more.   
     
     
         2 . The non-woven fabric composite material of  claim 1 , wherein the length of the coir fiber and the fiber made from the synthetic thermoplastic polymer is from 10 mm to 100 mm. 
     
     
         3 . The non-woven fabric composite material of  claim 1 , wherein the diameter of the coir fiber is from 150 μm to 500 μm. 
     
     
         4 . The non-woven fabric composite material of  claim 1 , wherein the coir fiber and the fiber made from the synthetic thermoplastic polymer are matted together using carding and needle punching, cyclone air deposition, chemical, heat, or solvent treatment. 
     
     
         5 . The non-woven fabric composite material of  claim 1 , wherein the weight ratio of the coir fiber to the fiber made from the synthetic thermoplastic polymer is from 95:5 to 20:80. 
     
     
         6 . The non-woven fabric composite material of  claim 1 , wherein the synthetic thermoplastic polymer is polypropylene, and wherein the matted material has been heated to a temperature throughout the matted material above 180° C. 
     
     
         7 . The non-woven fabric composite material of  claim 1 , wherein the fiber made from the synthetic thermoplastic polymer comprises polypropylene and wherein the matted material has been heated to a temperature throughout the matted material above 180° C. and lower than 240° C. 
     
     
         8 . The non-woven fabric composite material of  claim 1 , wherein the matted material has been heated to a temperature throughout the matted material between 200° C. and 230° C. and pressed at that temperature. 
     
     
         9 . The non-woven fabric composite material of  claim 1 , wherein the coir fiber and the fiber made from the synthetic thermoplastic polymer are pressed at a compression pressure ranging from 25 psi to 400 psi. 
     
     
         10 . A method of preparing a non-woven fabric composite material comprising:
 obtaining coir fiber;   milling the coir fiber to a desired fiber length;   mixing the milled coir fiber with a fiber made from or including a synthetic thermoplastic polymer, wherein the synthetic thermoplastic polymer is selected from the group consisting of polypropylene, polyethylene, polylactic acid, and mixtures thereof, and wherein the fiber made from the synthetic thermoplastic polymer has a lower viscous flow temperature than the degradation temperature of the coir fiber;   creating a matted material from the blended fibers using carding and needle punching, air deposition of fibers sprayed with a light glue, or other processes, to give a matted non-woven fabric composite material;   heating the matted material to a temperature throughout the matted material that is higher than the melt temperature of the fiber made from or including the synthetic thermoplastic polymer; and   pressing the heated matted material while at that temperature at a compression pressure range of 25 psi or more.   
     
     
         11 . The method of  claim 10 , wherein the coir fiber is stripped of its waxy coating and the coir fiber or the fiber made from the synthetic thermoplastic polymer is treated with a chemical compatibilizer to yield a graft copolymer. 
     
     
         12 . The method of  claim 10 , further comprising pressing the heated matted material using a die in a compression molding machine to become a shaped rigid part. 
     
     
         13 . The method of  claim 10 , wherein the fiber made from the synthetic thermoplastic polymer comprises polypropylene and further comprising heating the matted material to a temperature above 180° C. and lower than the degradation temperature of the coir fiber and pressing the heated matted material at that temperature. 
     
     
         14 . The method of  claim 10 , wherein the fiber made from the synthetic thermoplastic polymer comprises polypropylene and further comprising heating the matted material to a temperature above 180° C. and lower than 240° C. 
     
     
         15 . The method of  claim 10 , further comprising heating the matted material to a temperature between 200° C. and 230° C. and pressing the heated matted material at that temperature. 
     
     
         16 . The method of  claim 10 , further comprising pressing the heating matted material at a compression pressure range of 25 psi to 400 psi.