TECHNICAL FIELD

This invention relates to methods for making and using one or more thermally conductive foam layers comprising flexible cellular foam and metal material particulates, and said layers are located on, under, or in mattresses and bedding products. This invention more specifically relates to various types of thermally conductive foams containing metal material particulates including, but not necessarily limited to, mattresses, pillows, mattress topper pads, quilted toppers, medical mattresses and other bedding products.

TECHNICAL BACKGROUND

Flexible cellular foams such as open-cell polyurethane flexible foams, closed-cell polyurethane flexible foams, latex foams and melamine foams typically have low thermal conductivities in the range of about 0.035 to about 0.060 W/(m K). Materials with low thermal conductivities typically function as insulators, such as rigid polyurethane foam insulation board or expanded polystyrene insulation board.

Heat transfer consists of a combination of the phenomena of conduction, convection and radiation. In a cushion or mattress, heat transfer by radiation is not very large. Instead, heat transfer by conduction and convection are the primary paths for moving heat in and through a cushion or mattress. As a person sleeps on a mattress, the compressed foam underneath the body has reduced air flow paths, and the primary mode of heat transfer in the region below the body is conduction.

Heat is conducted from the body, through the compressed foam and dispersed into cushion or mattress regions where the foam is not compressed as much, which allows natural convection to occur more readily to remove heat from the mattress. Due to the low thermal conductivity of foam, this process is slow and requires a large temperature gradient to drive the conduction of heat at a rate similar to the heat production in a person's body. This results in a large region of hot foam around the body which makes the foam uncomfortable.

U.S. Pat. No. 3,255,128 discloses polyurethane foam compositions containing small particles of metallic aluminum and methods for treating the aluminum particles with phosphoric acid to enhance their usefulness in polyurethane foam. The phosphate aluminum flake was added to insulating polyurethane foam panels to decrease the heat flow through the panels by reducing absorption of heat and radiation.

U.S. Pat. No. 3,833,951 discloses flameproofed mattresses, pillows and sleeping bags. A metallized heat conductive layer is made by mixing a metal with an aqueous vinyl binder, and the frothed mixture is spread on a polyurethane foam having foam thickness between 0.1 to 1.0 inches and dried around 280° C. The final dried coating is 0.5 to 6 mils in thickness.

U.S. Pat. No. 6,772,825 B2 discloses a support surface for patient comfort and to maintain a cool skin temperature by having a refrigerant bladder with boiling point between 23 and 35 degrees Celsius contained within a bladder, a flexible spacer in the bladder such as polyurethane foam, and thermally-conductive aluminum or copper metal strips and a top metal layer located on the outside of the bladder. The strips of metal are used to transfer heat away from refrigerant gas into the surrounding environment. Metallic material was not added to the polyurethane foam reactants prior to producing the foam substrate.

It is useful and desirable to develop improved heat transfer in a cushion or mattress to provide a cooler and more comfortable sleep.

SUMMARY

There is provided, in one non-limiting form, methods of forming an enhanced thermally-conductive cellular foam (referred as “TO Foam” or thermally-conductive foam) comprised of a flexible polyurethane foam and/or polyester polyurethane foam, which may be open or closed celled in nature, and a plurality of metallic material particulates. Phase change materials, colorants, plasticizers, and other performance modifying additives may optionally be incorporated into the TC Foam. The TC Foam contains a metal material in the range of 0.5% to 70% on a weight basis.

Optionally, the TC Foam may be comprised of a plurality of metal material particulates and a latex foam, which may be of open or close celled nature. In this embodiment, phase change materials, colorants, plasticizers, and other performance modifying additives may optionally be incorporated into the TC Foam. The TC Foam contains a metal material in the range of 0.5% to 70% on a weight basis.

Optionally, the TC Foam may be comprised of a plurality of metal material particulates and a melamine foam, which may be of open or close celled nature. In this embodiment, phase change materials, colorants, plasticizers, and other performance modifying additives may optionally be incorporated into the TC Foam. The TC Foam contains a metal material in the range of 0.5% to 70% on a weight basis.

The metal material to be used in methods and compositions described herein may be selected from a non-limiting list of aluminum, copper, iron, steel, silver, gold, platinum, nickel, tin, chromium, vanadium, tungsten, and combinations thereof, or derivatives made from any of those materials combined with oxygen, halogens, carbon, or silicon, and any combination thereof. The metal material may be flakes, powders, crystalline arrangements, particulates, and combinations thereof.

The TC Foam may be cut or molded in many structures such as, but not limited to, planar layers, convoluted layers, surface modified layers, 3D surface texturing, molded pillows, smooth molded surfaces, molded surfaces with regular or irregular patterns, or modified in any way as to generate a desired physical structure such as but not limited to hole punching, channeling, reticulation or other method known to the art of foaming for modifying the structure of foam. The TC Foam may be adhered in the cushion or mattress composite with adhesive or melting of a thermoplastic on the foam surface and allowing the thermoplastic to re-solidify and lock the TC Foam in place on the substrate foam.

There is also provided, in a non-restrictive embodiment, combinations of suitable layering substrates including, but not limiting to, flexible polyurethane foam, latex foam, flexible melamine foam, and other substrates (such as fibers in woven or non-woven form) with one or more TC Foams. Articles that may be manufactured from these combinations of one or more TC Foams substrates including, but not necessarily limited to, mattresses, mattress toppers, pillows, bedding products, pet beds, quilted mattress toppers, pillow or mattress inserts, contoured support foam or other materials commonly used in the bedding environment.

