Heat reflecting composites with knitted insulation
Fabrics made for apparel, tents, sleeping bags and the like, in various composites, constructed such that there is at least one metal layer, forming a radiant barrier to reduce heat loss via radiation from the human body, and insulating this metal layer from heat loss via conduction, and a process for its manufacture.
1. An infra-red reflective composite, comprising:
a first moisture vapour permeable substrate having a bottom surface;
a first metal layer disposed on the bottom surface of the first moisture vapour permeable substrate;
a second moisture vapour permeable substrate having a top surface;
a second metal layer disposed on the top surface of the second moisture vapour permeable substrate;
an insulating textile layer disposed between the first metal layer and the second metal layer such that a top surface of the insulating textile layer is adjacent to the first metal layer and a bottom surface of the insulating textile layer is adjacent to the second metal layer, wherein the insulating textile layer covers substantially all of the first metal layer and the second metal layer; and
wherein said insulating textile layer has a substantially lower thermal conductivity than the first metal layer, and has a structure which comprises gaps at the top surface and bottom surface of the insulation textile layer which exposes a portion of the first metal layer for infra red reflection while also providing mechanical separation of the first metal layer from the second metal layer, and wherein the insulating textile layer comprises a non-woven structure formed with fibers.
2. The composite according to claim 1 , wherein said non-woven fibers are selected from the group consisting of a synthetic fiber, an organic fiber, and a combination of synthetic and organic fibers.
3. The composite according to claim 1 , wherein said textile layer is adjacent to said metal layer.
4. The composite according to claim 1 , wherein said insulating textile layer comprises at least one functional layer to provide at least one functional property to said insulating textile layer, and the functional layer of the insulating textile layer is disposed between the first metal layer and the textile layer.
5. The composite according to claim 4 , wherein the thickness of the functional coating is between 0.2 μm to 2.5 μm.
6. The composite according to claim 1 , further comprising a coating layer applied to a bottom surface of the first metal layer such that the coating layer is disposed between the first metal layer and the insulating textile layer.
7. The composite according to claim 6 , wherein said coating layer applied to the bottom surface of the first metal layer comprises an organic layer on the first metal layer.
8. The composite according to claim 7 , wherein the coating layer comprises a transition metal oxide selected from the group consisting of silicon dioxide, titanium dioxide, tungsten dioxide and zinc oxide.
9. The composite according to claim 1 , wherein the first moisture vapour permeable substrate comprises at least one material selected from the group consisting of a nonwoven fabric, woven fabric, nonwoven fabric-film laminate, woven fabric-film laminate, and microperforated film.
10. The composite according to claim 1 , wherein the first metal layer has a predetermined emissivity and comprises a material selected from the group consisting of Al, Cu, Au, Zn, Mg, Ti, Ag, Stainless steel, AgGe, CuZn, CuSn, CuAg, or CuAgSn.
11. The composite according to claim 1 , wherein the first metal layer is comprised of a metal or metal alloy layer selected so as to provide a predetermined level emissivity.
12. The composite according to claim 1 , wherein the metal layer comprises a silver precipitate for antibacterial properties.
13. The composite according to claim 1 , wherein the first metal layer has a thickness between approximately 10 nm and approximately 200 nm.
14. An article of clothing comprising an infra-red reflective composite that includes a first moisture vapour permeable substrate having a bottom surface;
a first metal layer disposed on the bottom surface of the first moisture vapour permeable substrate;
a second moisture vapour permeable substrate having a top surface;
a second metal layer disposed on the top surface of the second moisture vapour permeable substrate;
an insulating textile layer disposed between the first metal layer and the second metal layer such that a top surface of the insulating textile layer is adjacent to the first metal layer and a bottom surface of the insulating textile layer is adjacent to the second metal layer; and
wherein said insulating textile layer has a substantially lower thermal conductivity than the first metal layer, and has a structure which comprises gaps at the top surface and bottom surface of the insulation textile layer which exposes a portion of the first metal layer for infra red reflection while also providing mechanical separation of the first metal layer from the second metal layer, and wherein the insulating textile layer comprises a non-woven structure formed with fibers.
15. The article of clothing according to claim 14 , wherein at least one of the first moisture vapour permeable substrate and the first metal layer further comprises a functional coating, such that the functional coating is positioned between the first metal layer and the first moisture vapour permeable substrate.
16. The article of clothing according to claim 14 , wherein an outer layer is applied to the first metal layer to improve mechanical abrasion and reduce oxidation of the first metal layer.
17. The article of clothing according to claim 16 , wherein the thickness of the outer layer is between 0.2 μm to 2.5 μm.