Cigarette Burn Resistant Mattresses Having Aluminized Polyurethane Foam Layer

Abstract

This invention is concerned with flameproofed mattresses, pillows and sleeping bags, pads, cushions for chair or sofas, and so on. The flameproofed materials of the present invention may be formed of (1) a close-woven fabric attached to (2) a thick layer (e.g., 0.1-1 inch) of resilient self-extinguishing polyruethane cushioning foam having (3) a metallized heat-conductive layer, such as of aluminum, which dissipates heat rapidly, thereupon, the metallized foam being secured to (4) filling or padding with (5) a backing fabric secured thereto. The parts are suitably locally secured together by tying means such as stitching, tufting, dielectric welding or the like. The object is to protect the main body of highly combustible filler material in cushions, pillows, mattresses, sofas, upholstered chairs, and the like from fire in case of the dropping of a match, cigarette, or the like on the cover fabric or ticking by someone, such as a careless smoker. Even though the foam is self-extinguishing relative to a lighted cigarette, when not compressed, when it is compressed by tying as by stitching, the heat may be conducted therethrough and ignite the filling or stuffing, if no metal layer is present.

Description

DESCRIPTION OF THE INVENTION

It has heretofore been the practice in making ironing board covers to apply a coating of metal particles, such as of aluminum, to the face or back of the cover to provide rapid dissipation of heat. However, ticking fabric materials are in general, relatively thin and generally have a printed decorative design on the exposed face. Consequently, the placing of a metal-particle-containing layer directly on the face would obscure the design and if it were placed on the back or inside surface of the ticking fabric, it results in an undesirable appearance of the coated ticking because the metal layer is visible to observers as they look at the outside of the covered article, such as a mattress, the effect observed being commonly referred to as "grin-through." In addition, the metal-coated covering fabric is stiffened detrimentally.

Polyurethane foam cushioning layers between mattress ticking and the stuffing or padding thereof is commonly used to serve as a self-extinguishing and insulating layer between the ticking and the stuffing for the purpose of preventing accidental ignition of the mattress. It has been found by applicant, however, that in areas where the polyurethane foam is compressed to a minor fraction of its original thickness, for example, reduced in thickness from 1/2 or 5/8 inch to 1/8 or 1/16 inch or less by tying means such as stiching or tufting, the insulating properties of the polyurethane foam are reduced or lost, and a lighted cigarette placed on that compressed area will often cause ignition of the cotton or other stuffing underlying the polyurethane foam layer causing a smoldering fire.

The present invention compensates for this deficiency by providing, particularly in localized areas such as edges or tufted or stitched areas where the foam is compressed, a heat conductive layer of metallic material, usually powdered or flaked metal held together by a binder, whereby the heat in the areas of compression of the foam, that would otherwise be conducted to the flammable material, is conducted away by the metal. The metal coating may be either on the face of the foam adjacent to the ticking or on the face adjacent to the stuffing, preferably the latter in order to prevent "grinning" of the metal through the ticking. The ticking may be of damask or a loosely woven rayon fabric, either having a decorative design thereon by printing or by weaving.

The drawings illustrate the invention.

FIG. 1 shows a damask or rayon ticking 1 attached to a polyurethane cushioning foam layer 2, in turn bearing a metallized coating 3. The ticking and metallized polyurethane foam are secured to the stuffing 4 by tying means such as stitching or tufting 6 through the respective layers including a fabric backing 5 such as muslin.

FIG. 2 illustrates essentially the same structure except that the metallized coating 3a is on the surface of the polyurethane layer adjacent the ticking, rather than on that surface adjacent the stuffing. The cushioning foam is suitably about 0.1 to 1.0 inch in thickness with a density of about 0.25 to 10 pounds per cubic foot.

The composite of the present invention prevents burning of the fibrous filler body of pads, cushions, pillows, mattresses, sofas, and the like when a lighted cigarette or match comes into contact with the cover fabric or ticking enclosing the fibrous filling material, especially at areas where the foam is locally compressed by tying means such as tufting or stitching to a small fraction of its normal thickness such that the self-extinguishing properties and insulating properties are adversely affected to an extent which would permit ignition of the fibrous filling, absent said metal. The lighted object may cause smoldering or burning of a small area in direct contact with the burning segment of a cigarette, match, or the like, but the combustion of this small area quickly brings the metal coating into play and, as a consequence, the heat in that small area is quickly dissipated by the metal layer, rapidly bringing the burning or smoldering items or segments down in temperature so that they themselves are extinguished and preventing the rise in temperature of the highly combustible fibrous filling material to the temperature of ignition or combustion.

The thickness of the metal coating or layer may be from about 1/2 to 6 mils, preferably 2 to 4 mils. The metal in the coating may be a powdered metal the particles being bonded together by an organic binder preferably of a combustion-resistant material, or the metal may be applied by a chemical plating or an electroplating process wherein no organic binder is used. Again, the metal may be applied by a sputtering process or by a vacuum metallizing process wherein a small amount of metal is vaporized in a vacuum within which the crushed foam/ticking laminate is either disposed with the ticking surface as well as the crushed foam surface exposed or disposed with a removable protective film, e.g., of polyethylene, against the front face of the ticking to prevent its being coated by the metal, the protective film being removed after the metallizing operation, if desired. A wide variety of metals may be used, such as aluminum, nickel, silver, bismuth, antimony, tin, gold, and alloys, such as stainless steel, brass, bronze, solder, woods, metal, etc. At present aluminum is preferred.

When the metal is deposited by applying a coating composition comprising the metal particles in a polymeric binder, the proportion of metal should be at least about 25 percent by weight of the binder, and preferably is at least 40 to 50 percent or more by weight thereof. The amount of the metal-containing coating is from about 0.5 to 4 oz./sq. yard and preferably 1 to 2 oz./sq. yard.

The metal layer may be continuous or it may also be in the form of a foamed or a crushed foam layer wherein it is somewhat discontinuous, but has the advantage of being more or less permeable, i.e., it has the quality of breathability, which makes it more comfortable to a person sitting or lying upon the pad, cushion, mattress, or the like, especially in hot weather.

When the metal layer is formed from a metal powder/binder composition, the binder used should be of a flame-resistant polymer, such as a polymer of vinyl chloride, vinylidene chloride, or other halogen-containing vinyl monomer. Regardless of what type of polymer is used, it should be one that is of flexible, rather than stiff, nature.

Preferred compositions are those based on aqueous dispersions of emulsion copolymers of monoethylenically unsaturated monomers having a group of the formula ##SPC1##

including vinyl monomers, especially of vinyl chloride, vinylidene chloride or mixtures thereof. Since the monomers produce hard and rigid homopolymers, they are copolymerized with monomers which, when homopolymerized produce polymers which are soft and flexible. Examples of the latter type of monomer are ethylene, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate which are included in the general class of acrylic acid esters of alcohols having 1 to 18 or more carbon atoms and amyl methacrylate, 2-ethylhexyl methacrylate and octadecyl methacrylate which are included in the general class of methacrylic acid esters of alcohols having 5 to 18 carbon atoms. The copolymers may also include appreciable amounts of other hardening monomers, such as styrene, vinyltoluene, acrylonitrile, and vinyl acetate provided the particular softening monomer in the amount thereof used is able to provide the desired flexibility for the particular laminated covering material in its intended use without requiring a reduction of the halogenated monomer to such an extent as to make the binder of the metal layer too susceptible to combustion. The copolymer may also comprise small amounts (0.1 to 2 percent by weight) of an acid such as acrylic acid, methacrylic acid, and itaconic acid, to provide improved stability of the emulsion polymer and ease of thickening by adjustment of pH of the system. Small amounts (0.5 to 5 percent by weight) of other reactive monomers may be included to provide self-crosslinking properties to the copolymer and/or to favor reaction of the metal layer binder with the intermediate foam layer and thereby provide chemical bonding and the advantages of this type of adhesion between the metal layer and the intermediate foam layer.

The amount of powdered metal in such compositions should be at least about 20 percent by weight, based on the total solids weight of the composition, and is preferably 40 to 50 percent or more by weight of the total solids.

The dry weight of the powdered metal-containing coating layer should be in the range of 0.5 to 4 ounces per square yard, per coating, using a single or double coating. The metal particles may have a wide range of sizes. Metal particles of sizes in the range of 0.02 to 0.1 mm., preferably 0.03 to 0.05, are quite practical. The selection of size is made to assure extensive contact between the metal particles to provide for rapid conduction of heat from one area to another in the coating.

In the metal coatings obtained by chemical or electrical plating, by sputtering, or by vacuum metallization, it is only necessary to provide adequate weight of metal deposit to obtain essential continuity of the metal coating film deposited, but much heavier thicknesses of the metal are permissible. Generally, a metal deposit of about 0.1 ounce of more, e.g., to 0.5 oz./sq. yard is adequate. In this situation, the upper limit of thickness or weight of metal is determined by the amount of flexibility necessary in the particular use. While a metal foil may be used, it is preferable to avoid it because of the tendency to develop a crackling noise when the composite cover fabric is flexed.

The present invention is applicable to provide a wide variety of materials adapted to serve as pads, sleeping bags, mattresses, pillows, cushions, upholstered chairs, beds, sofas, and so forth.

In the following examples, which are illustrative of the invention, parts and percentages are by weight and temperatures are .degree.F. unless otherwise specified.

EXAMPLE 1

a. An aluminum powder (25 parts) containing metal particles of about 0.02 to 0.04 mm. size is mixed with 100 parts of a 46 percent solids aqueous dispersion of an 80/20 weight ratio mixture of (1) an emulsion copolymer of about 66 vinylidene chloride, 29 percent butyl acrylate, 0.5 percent itaconic acid, about 3 percent acrylamide, and about 2 percent N-methylolacrylamide, and (2) an emulsion copolymer of about 96 percent of butyl acrylate, 2 percent of methacrylamide and 2 percent of N-methylolacrylamide, 2 parts of methylene-bis-diamylphenoxypoly(9)ethoxyethanol, 8 parts of a 25 percent aqueous solution of diammonium hydrogen phosphate, 15 parts of a 50 percent aqueous solution of a copolymer of about 60 percent ethyl acrylate, 39.5 percent methyl methacrylate and about 0.5 percent of diallyl phthalate, and 42.5 parts of water. The mixture is thoroughly stirred, yielding a 40 percent solids coating composition.

b. The resulting 40 percent solids composition obtained in part (a) is coated onto the exposed surface of an uncompressed, resilient polyurethane foam to provide a 6-mil thick layer thereon. The coated assemblage is then dried 4 minutes at 280.degree.F., yielding a deposit of about 2 oz./sq. yard.

c. A simulated mattress for testing purposes is made by placing a piece of cotton wadding (such as is used as mattress stuffing) 6 inches wide 15 inches long and 4 inches thick in the center of an 80.sup.2 cotton ticking fabric 12 inches wide by 15 inches long so that the 15-inch dimensions of the wadding and the fabric extend in the same direction. Then a 12-inch by 15-inch piece of the polyurethane foam cover fabric is laid on top of the batting with its 12-inch and 15-inch dimensions coinciding with the corresponding dimensions of the bottom fabric layer and with its metal-coated face in contact with the wadding, followed by an overlay of damask ticking. The two fabrics are sewn together along the 15-inch edges of the wadding to compress the wadding and the foam along the edges. Also, the wadding and foam are compressed along a central line parallel to the sewn edges by sewing the assemblage together along such central line. The resulting simulated pad or mattress may then, if desired, be stretched taut by fastening the extended edges of one or both cotton fabrics to opposite sides of a square frame having a square opening within the four edge members thereof. The resulting pad has a trough formed by the central sewn line between two parallel bulged ridges one on each side of the central line. For testing, a burning cigarette is placed on the pad, either on top of one of the ridges, but preferably in the groove between them. The cigarette is allowed to burn itself out; if the wadding ignites, the ticking is a failure but if the wadding does not ignite before the cigarette burns out, the ticking passes the test.

d. The simulated mattress obtained above, when tested in the fashion described in part (c) hereof, passes the test.

EXAMPLE 2

The procedure of Example 1 is repeated except that in part (a) thereof, the metal-containing composition is modified by inclusion of a foam stabilizer or agent, specifically a mixture of about 4.3 parts of a 33 percent aqueous solution of ammonium stearate and 1.4 parts of a 33 percent aqueous solution of sodium lauryl sulfate. The mixture is beaten into a foam which is spread on the surface of the polyurethane foam to provide a thickness of about 60 mils and after drying for 2 minutes at 280.degree. F., the composite is passed through squeeze rolls of a textile pad to crush the foamed metal-containing layer after which curing is completed by heating 4 minutes at 280.degree. F., yielding a composite material in which the metal-containing coating is present in an amount of about 3.5 oz./sq. yard. This metal-coated resilient polyurethane foam, when made into a simulated mattress, passes the test described in Example 1 (d).

EXAMPLE 3

Example 1 is repeated except in part (a) thereof the aqueous dispersion is a 90/10 weight ratio mixture of (1) an emulsion copolymer of about 69 percent vinyl chloride, 29 percent butyl acrylate, 1 percent methylolacrylamide, 1/2 percent acrylamide and 1/2 percent itaconic acid and (2) an emulsion copolymer of about 96 percent butyl acrylate, 2 percent methacrylamide and 2 percent methylolmethacrylamide.

EXAMPLE 4

The process of Example 1 is carried out except that in part (a) the aluminum powder is replaced with 23 parts of stainless steel powder, the particles of which range in size from 0.05 to 0.1 mm. The simulated mattress passes the test.

EXAMPLE 5

The process of Example 1 is carried out except that in part (a) the aluminum powder is replaced with 23 parts of silver powder, the particles of which range in size from 0.03 to 0.07 mm. The simulated mattress passes the test.

EXAMPLE 6

The process of Example 1 is carried out except that in part (a) the aluminum powder is replaced with 23 parts of nickel powder, the particles of which range in size from 0.03 to 0.06 mm. The simulated mattress passes the test.

EXAMPLE 7

The process of Example 1 is carried out except that in part (a) the aluminum powder is replaced with 23 parts of tin powder, the particles of which range in size from 0.02 to 0.04 mm. The simulated mattress passes the test.

EXAMPLE 8

The process of Example 1 is carried out except that in part (a) the aluminum powder is replaced with 23 parts of anodized aluminum powder, the particles of which range in size from 0.02 to 0.04 mm. The simulated mattress passes the test.

EXAMPLE 9

The process of Example 1 is carried out except that in part (a) the aluminum powder is replaced with 23 parts of bronze powder, the particles of which range in size from 0.03 to 0.7 mm. The simulated mattress passes the test.

While self-extinguishing polyurethane foamed plastic has been specified, other foamed plastics having the desired cushioning, heat insulating, and self-extinguishing properties may serve as the functional equivalent thereof.

The term "self-extinguishing" as applied to plastic foams herein is intended to include ordinary polyurethane foams which, because of their uncompressed condition and porosity, will not become ignited by a lighted match or cigarette. Also included are chemically treated foams which will not ignite or continue to smolder when exposed to a blowtorch flame.

Claims

I claim:

1. A mattress, pad, or the like comprising a lightweight woven or a damask fabric, a soft, flexible layer secured thereto formed of a resilient, self-extinguishing plastic heat-insulating and cushioning foam of about 0.1 to 1.0 inch in thickness, and a metal-containing coating on the resilient foam layer, the metal content of which serves to conduct heat rapidly away from any point to which heat is applied, said metal-coated foam being adjacent a combustible padding or filling body, in turn lying upon a fabric backing, all of the recited elements being secured to one another by tying means which locally compress said cushioning foam thus diminishing its heat insulating properties at said compressed locations, whereby heat from a heat source at the ignition temperature of the padding or filling which is applied to said compressed locations is dissipated by said metal-containing layer.

2. An article according to claim 1 in which the cushioning foam is a polyurethane foam.

3. An article according to claim 1 in which the metal-containing layer comprises crushed foam.

4. An article according to claim 1 in which the thickness of the metal-containing coating is from 0.5 to 6 mils.

5. An article according to claim 2 in which the metal in the metal-containing layer is selected from the group consisting of aluminum, nickel, silver, bismuth, antimony, tin, gold, stainless steel, brass, bronze and Wood's metal.

6. An article according to claim 5 in which the metal is aluminum having a particle size in the range of 0.02 to 0.1 mm. in an organic binder.

7. An article according to claim 6 in which the metal is anodized aluminum.

8. An article according to claim 5 in which the metal is stainless steel having a particle size in the range of 0.02 to 0.1 mm. in an organic binder.

9. An article according to claim 5 in which the metal-containing layer is adhered to said cushioning foam on the side thereof which is adjacent to the filling or padding and in which said latter material is formed of combustible fibers.