Method for preparing nanodiamond-containing thermoplastic fibers and the use of such fibers in yarns and fabrics

Abstract

The present disclosure relates to methods for preparing nanodiamond-containing thermoplastic fibers and filaments having diamond particles substantially uniformly distributed throughout. The process comprises melt extruding a material comprising a thermoplastic polymer and from about 0.001% to about 0.25% by weight nanosized diamond particles. The present disclosure also relates to yarns and fabrics comprising the nanodiamond-containing thermoplastic fibers or filaments, and to garments comprising these yarns and/or fabrics. Yarns and fabrics comprising nanodiamond-containing thermoplastic fibers and filaments have been found to have enhanced thermal properties, enhanced mechanical properties, and/or enhanced softness.

What is claimed is: 
     
         1 . A method for preparing a nanodiamond-containing thermoplastic fiber comprising:
 melt extruding a material comprising
 at least 98.0% by weight thermoplastic polymer, and 
 from about 0.001% to about 0.25% by weight diamond particles having particle sizes between about 2 and about 500 nm; 
   to produce a fiber having diamond particles substantially uniformly distributed throughout the fiber.   
     
     
         2 . The method of  claim 1 , wherein the nanodiamond-containing thermoplastic fiber contains from about 0.005% to about 0.100% by weight diamond particles. 
     
     
         3 . The method of  claim 1 , wherein the thermoplastic polymer is selected from the group consisting of: polyesters, polypropylene, polycarbonate, polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), polytrimethylene naphthalate (PTN), polyether ketone (PEK), polyether ether ketone (PEEK), poly(p-phenylene sulfide) (PPS), polyamides (nylon), thermoplastic polyurethanes (TPU), thermoplastic elastomers (TPE), and combinations thereof. 
     
     
         4 . The method of  claim 1 , wherein the thermoplastic polymer comprises one or more polyamides. 
     
     
         5 . The method of  claim 4 , wherein the thermoplastic polymer comprises nylon 6,6; nylon 6; or a combination thereof. 
     
     
         6 . The method of  claim 1 , wherein the diamond particles have particle sizes between about 2 nm and about 10 nm. 
     
     
         7 . The method of  claim 1 , wherein the melt extruding comprises at least the following two steps:
 a. preparing diamond concentrate pellets comprising
 a first thermoplastic polymer, 
 about 0.1% to about 10% by weight diamond particles, and 
 about 0.1% to about 1% by weight dispersion agent; and 
   b. preparing the nanodiamond-containing thermoplastic fiber by melt extruding a mixture of a second thermoplastic polymer and the diamond concentrate pellets prepared in step (a).   
     
     
         8 . The method of  claim 7 , wherein the second thermoplastic polymer is a polyamide. 
     
     
         9 . The method of  claim 8 , wherein the first thermoplastic polymer is a polyamide. 
     
     
         10 . The method of  claim 9 , wherein the first thermoplastic fiber is nylon 6 and the second thermoplastic polymer is nylon 6,6. 
     
     
         11 . The method of  claim 7 , wherein the first thermoplastic polymer and the second thermoplastic polymer differ from one another. 
     
     
         12 . The method of  claim 7 , wherein the first thermoplastic polymer and the second thermoplastic polymer are the same. 
     
     
         13 . The method of  claim 7 , wherein the dispersion agent comprises zinc stearate, calcium stearate, or a mixture thereof. 
     
     
         14 . The method of  claim 7 , wherein step (a) comprises heating the first thermoplastic polymer to form a viscous phase, blending the nanodiamond particles and dispersion agent into the first thermoplastic polymer, and extruding the resulting mixture. 
     
     
         15 . The method of  claim 7 , wherein step (b) comprises feeding pellets of the second thermoplastic polymer and the diamond concentrate pellets into an extruder in controlled quantities to produce a nanodiamond-containing thermoplastic fiber that contains a predetermined concentration of nanodiamond. 
     
     
         16 . The method of  claim 1 , wherein incorporation of the diamond particles produces at least a 5% increase in the thermal conductivity of the fiber in contrast to the fiber without the diamond particles. 
     
     
         17 . The method of  claim 1 , wherein incorporation of the diamond particles produces a substantial increase in the strength of the fiber over the fiber without the diamond particles, without producing a substantial decrease in elongation. 
     
     
         18 . A nanodiamond-containing thermoplastic fiber comprising:
 about 99.0% to about 99.9% by weight thermoplastic polymer;   about 0.001% to about 0.25% by weight diamond particles, the diamond particles having particle sizes between about 2 and about 500 nm;   about 0.002% to about 0.02% by weight dispersion agent.   
     
     
         19 . The nanodiamond-containing thermoplastic fiber of  claim 18 , wherein the thermoplastic polymer is nylon. 
     
     
         20 . The nanodiamond-containing thermoplastic fiber of  claim 18 , wherein the dispersion agent comprises zinc stearate, calcium stearate, or a mixture thereof. 
     
     
         21 . The nanodiamond-containing thermoplastic fiber of  claim 18 , wherein the nanodiamond-containing thermoplastic fiber comprises about 0.005% to about 0.100% by weight diamond particles. 
     
     
         22 . The nanodiamond-containing thermoplastic fiber of  claim 21 , wherein the diamond particles have particle sizes between about 2 nm and about 10 nm. 
     
     
         23 . The nanodiamond-containing thermoplastic fiber of  claim 18 , wherein the nanodiamond-containing thermoplastic fiber has at least a 5% higher thermal conductivity than a fiber containing only the thermoplastic polymer. 
     
     
         24 . The nanodiamond-containing thermoplastic fiber of  claim 18 , wherein the nanodiamond-containing thermoplastic fiber has at least a 4% higher strength than that of a fiber containing only the thermoplastic polymer and an elongation that is within about 2% of that of the fiber containing only the thermoplastic polymer. 
     
     
         25 . The nanodiamond-containing thermoplastic fiber of  claim 18 , further comprising about 0.001% to about 0.25% by weight sub-micron particles of boron nitride, graphite, graphene, silica, one or more aluminosilicates, or a combination thereof. 
     
     
         26 . A fabric comprising the nanodiamond-containing thermoplastic fiber of  claim 18 . 
     
     
         27 . A garment comprising the fabric of  claim 26 , the garment being configured to provide transfer heat away from a wearer's body. 
     
     
         28 . A method of increasing the thermal conductivity of a fabric comprising:
 preparing a fiber having
 at least 98.0% by weight thermoplastic polymer, and 
 from about 0.005% to about 0.100% by weight diamond particles having particle sizes between about 2 and about 500 nm, wherein the diamond particles are substantially uniformly distributed throughout the fiber; 
   incorporating the fiber into a yarn; and   preparing a fabric that comprises the yarn;   wherein incorporation of the diamond particles in the fabric produces at least a 5% increase in the thermal conductivity of the fabric in contrast to the fabric without the diamond particles.   
     
     
         29 . A method of increasing the strength of a fabric without a significant loss in the elongation of the fabric, comprising:
 preparing a fiber having
 at least 98.0% by weight thermoplastic polymer, and 
 from about 0.005% to about 0.100% by weight diamond particles having particle sizes between about 2 and about 500 nm, wherein the diamond particles are substantially uniformly distributed throughout the fiber; 
   incorporating the fiber into a yarn; and   preparing a fabric that comprises the yarn;   
       wherein incorporation of the diamond particles in the fabric produces a substantial increase in the strength of the fabric in contrast to the fabric without the diamond particles, without producing a substantial decrease in elongation of the fabric.