Thin insulative material with gas-filled cellular structure

Abstract

The present invention is directed to a lightweight, gas-filled, highly insulative cellular structure and methods for manufacturing the cellular structure. The cellular structure can be incorporated into outdoor gear and apparel to make the outdoor gear or apparel warm, while still maintaining a desired thinness and flexibility. The insulative article takes advantage of the superior insulative properties of dry gases and preferably highly insulative gases such as argon. In addition, the size and shape of the cells in the cellular structure are selected to minimize convection.

1 . A lightweight, gas-filled, highly insulative material, comprising:
 a first sheet of a gas impermeable material and a second sheet of a gas impermeable material joined together to form a chamber having a cell structure, the cell structure comprising a plurality cells that are in fluid communication;   a dry insulating gas disposed within the plurality of cells; and   a dry gas reservoir and a valve mechanism configured to allow the dry insulating gas to be introduced and removed from the plurality of cells;   wherein the dimensions of the plurality of cells are such that free convective mixing of the insulating gas is minimized within the cells by selecting dimensions for the cells and the dry insulating gas so as to yield a Rayleigh value of less than 300,000 for each cell.   
     
     
         2 . An insulative material as in  claim 1 , wherein the insulative material is incorporated into an article of outdoor apparel chosen from the group consisting of coats, parkas, jackets, vests, pants, gloves, mittens, hats, liners, waders, and snow boots, work boots, ski boots, and snowboard boots. 
     
     
         3 . An insulative material as in  claim 1 , wherein the insulative material is incorporated into an article of outdoor gear chosen from the group consisting of tents, sleeping bags, bivouac bags, and sleeping pads. 
     
     
         4 . An insulative article as recited in  claim 1 , wherein the gas impermeable material for the first and second sheets comprises a fabric bonded or laminated to a gas impermeable material. 
     
     
         5 . An insulative article as recited in  claim 4 , wherein the gas impermeable material is selected from the group consisting of polyethylene, polypropylene, polyurethane, urethane, silicone rubber, latex rubber, polytetrafluoroethylene (PTFE), expanded PTFE, butyl rubber, and Mylar. 
     
     
         6 . An insulative article as recited in  claim 1 , wherein the dry insulating gas is dry atmospheric air having a moisture content less than about 4 percent by weight. 
     
     
         7 . An insulative article as recited in  claim 1 , wherein the dry insulating gas is selected from the group consisting of argon, krypton, xenon, carbon dioxide, sulfur hexafluoride, and combinations thereof. 
     
     
         8 . An insulative article as recited in  claim 7 , wherein the dry insulating gas has a moisture content not greater than about 2 percent by weight. 
     
     
         9 . An insulative article as recited in  claim 7 , wherein the dry insulating gas has a moisture content not greater than about 1 percent by weight. 
     
     
         10 . An insulative article as recited in  claim 1 , wherein a volume and cell dimensions for each of the plurality of cells are selected such that the Rayleigh value of the is less than about 300,000. 
     
     
         11 . An insulative article as recited in  claim 10 , wherein the cell volume is less than about 300 cm 3  with dimensions of about 3 cm by about 14 cm by about 7 cm. 
     
     
         12 . An insulative article as recited in  claim 10 , wherein the cell volume is less than about 145 cm 3  with dimensions of about 3 cm by about 12 cm by about 4 cm. 
     
     
         13 . An insulative article as recited in  claim 10 , wherein the cell volume is less than about 100 cm 3  with dimensions of about 3 cm by about 8 cm by about 4 cm. 
     
     
         14 . An gas-filled, highly insulative article of outdoor gear or outdoor apparel, comprising:
 a material sized and configured to be worn by a person;   a gas-filled insulative cell structure, the cell structure having,
 a first sheet of a gas impermeable material and a second sheet of gas impermeable material joined together to form a cell; 
 an insulative gas disposed with the cells and having a moisture content of less than about  4  percent by weight; and 
 wherein the dimensions of the plurality of cells are such that free convective mixing of the insulating gas is minimized within the cells by selecting dimensions for the cells and the dry insulating gas so as to yield a Rayleigh value of less than 300,000 for each cell 
   
     
     
         15 . An article of outdoor gear or outdoor apparel selected from the group consisting of consisting of coats, parkas, jackets, vests, pants, gloves, mittens, hats, liners, snow boots, work boots, ski boots, snowboard boots, tents, sleeping bags, bivouac bags, and sleeping pads. 
     
     
         16 . An article of outdoor gear or outdoor apparel as recited in  claim 14 , wherein the insulating gas is selected from the group consisting of atmospheric air, argon, krypton, xenon, carbon dioxide, sulfur hexafluoride, and combinations thereof. 
     
     
         17 . An article of outdoor gear or outdoor apparel as recited in  claim 14 , wherein the cell volume is less than about 300 cm 3  with dimensions of about 3 cm by about 14 cm by about 7 cm. 
     
     
         18 . An article of outdoor gear or outdoor apparel as recited in  claim 14 , wherein the cell volume is less than about 145 cm 3  with dimensions of about 3 cm by about 12 cm by about 4 cm. 
     
     
         19 . An article of outdoor gear or outdoor apparel as recited in  claim 14 , wherein the cell volume is less than about 100 cm 3  with dimensions of about 3 cm by about 8 cm by about 4 cm. 
     
     
         20 . An article of outdoor gear or outdoor apparel as recited in  claim 14 , wherein a plurality of insulative cells are grouped together to form an insulative article. 
     
     
         21 . A method of manufacturing a lightweight, gas-filled, highly insulative article, comprising:
 providing a first sheet of a gas impermeable material and a second sheet of a gas impermeable material;   welding the first and seconds sheets of gas impermeable material together to form a chamber having a cell structure comprising a plurality cells that are in fluid communication, wherein the volume and dimensions of the plurality of cells are chosen such that free convective mixing of gas inside the cells is minimized, the cell structure   providing a valve mechanism configured to allow an insulating gas to be introduced into and removed from the plurality of cells; and   filling the plurality of cells with a dry insulating gas selected from the group consisting of atmospheric air, argon, krypton, xenon, carbon dioxide, sulfur hexafluoride, and combinations thereof, wherein the insulating gas has a moisture content less than about  4  percent by weight.   
     
     
         22 . A method as recited in  claim 21 , wherein the gas impermeable material for the first and second sheets comprises a fabric bonded or laminated to a gas impermeable material. 
     
     
         23 . A method as recited in  claim 21 , wherein the gas impermeable material is selected from the group consisting of polyethylene, polypropylene, polyurethane, urethane, silicone rubber, latex rubber, polytetrafluoroethylene (PTFE), expanded PTFE, butyl rubber, and Mylar. 
     
     
         24 . A method as recited in  claim 21 , wherein the further comprising choosing a volume and cell dimensions for each of the plurality of cells such that the Rayleigh value of each of the plurality of cells is below 300,000. 
     
     
         25 . A method as recited in  claim 21 , further comprising incorporating the insulative articles into outdoor apparel and/or gear chosen from the group consisting of coats, parkas, jackets, vests, gloves, mittens, hats, liners, snow boots, work boots, ski boots, snowboard boots, tents, sleeping bags, bivouac bags, and sleeping pads.