2. Description of the Prior Art Canadian Patent Application No. 2,211,549 laid-open on March 4,1998 corresponding to PCT Publication No. WO 98/10216 published on March 12,1998, both in the names of Krona Industries Ltd. and naming Rangvald Aanestad as inventor, discloses a multi-layer flexible insulation (hereinafter sometimes referred to as the"KRONA Insulation Material") comprising a pair of closed-cell insulation sheets made of a multi-cellular plastic. film (e. g. closed-cell air bubbles or bubble-pack) which are laminated on both sides of a thin central white polyethylene film. A pair of aluminum foil layers or films are adhesively mounted on the outer surfaces of the bubble-pack insulation sheets, and a pair of thin clear outer polyester layers are provided on the outer surfaces of the aluminum layers. The aluminum layers are vapor-deposited on the outer polyester layers and are assembled to the hot bubble-pack insulation sheets while the latter are cooled. The bubble-pack insulation sheets are then adhered to the central polyethylene film with a hot melt glue. If the polyester layers are highly smooth, the aluminum films can'be deposited thereon in a uniform state thereby providing a high reflectivity, low emissivity, laminate. Furthermore, the outer polyester layers or coatings also protect the aluminum layers such as to prevent any aluminum from rubbing off the insulation and also prevent the aluminum layers from oxidizing. Furthermore, the polyester coatings provide a hygiene barrier for the insulation.

SUMMARY OF THE INVENTION It is therefore an aim of the present invention to provide an improved multi-layer material which is provided with fire retardant properties.

Therefore, in accordance with the present invention, there is provided a multi-layer material comprising at least one insulative layer and an outer fire-retardant layer provided outwardly on at least one side of said insulative layer, wherein said insulative layer comprises a bubble-pack material.

An outer fire-retardant layer may be provided outwardly on each side of said insulative layer.

More particularly, the fire-retardant layer is made of fiberglass provided with fire-retardant properties. The fiberglass may comprise a fiberglass layer coated with a fire-retardant coating of an intumescent and/or non-intumescent composition.

Two insulative layers may be provided between the pair of outer fire-retardant layers, and an inner fire-retardant layer may be provided between the two insulative layers.

An aluminum foil film can be provided between each said insulative layer and a respective one of said outer fire-retardant layers. A polyester layer is provided outwardly on each said aluminum foil film.

Alternatively, an aluminum foil film may be provided outwardly of each said outer fire-retardant layer, a polyester layer being provided outwardly on each said aluminum foil film.

An aluminum foil film may be provided between the two insulative layers, a polyester layer being provided outwardly on each side of said aluminum foil film.

Typically, at least one insulation layer is made of bubble-pack material, for instance made of

polyethylene, which, when subjected to heat, melts and becomes an important fire retardant itself as the air bubbles are replaced by intumescence and the"bubble- pack"layer becomes a hard, fire retardant, plastic sheet.

BRIEF DESCRIPTION OF THE DRAWINGS Having thus generally described the nature of the invention, reference will now be made to the accompanying drawings, showing by way of illustration a preferred embodiment thereof, and in which: Fig. 1 is a perspective schematic view of a first embodiment of a multi-layer fire retardant material in accordance with the present invention, wherein the various layers thereof are shown in part in a separated relation for illustration purposes; Fig. 2 is a perspective schematic view of a second embodiment of a multi-layer fire retardant material in accordance with the present invention, wherein the various layers thereof are shown in part in a separated relation for illustration purposes; Fig. 3 is a perspective schematic view of a third embodiment of a multi-layer fire retardant material in accordance with the present invention, wherein the various layers thereof are shown in part in a separated relation for illustration purposes; Fig. 4 is a perspective schematic view of a fourth embodiment of a multi-layer fire retardant material in accordance with the present invention, wherein the various layers thereof are shown in part in a separated relation for illustration purposes; and Fig. 5 is a perspective schematic view of a fifth embodiment of a multi-layer fire retardant material in accordance with the present invention, wherein the various layers thereof are shown in part in a separated relation for illustration purposes.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Figs. 1 to 5 show various embodiments in accordance with the present invention of a multi-layer material having fire retardant properties and, in the illustrated embodiments, having also insulation layers.

More particularly, Fig. 1 illustrates a first fire retardant material 10 which includes a central layer 12 made of a fibreglass saturated with a fire retardant, a pair of bubble-pack insulation layers 14 provided on opposed outside surfaces of the central layer 12, a pair of aluminum foil layers or films 16 provided on the outer surfaces of the insulation layers 14, a pair of polyester films 18 provided on the outer surfaces of the aluminum foil films 16, and a pair of outside layers 20 provided on the outside surfaces of the polyester films 18 and, similarly to central layer 12, made of fibreglass saturated with a fire retardant. Typically, the central and outside layers 12 and 20 are made of fibreglass which is coated on both of its sides with a fire retardant and are glued to their respective adjacent layer (s).

It is noted that the multi-layer fire retardant material of the present invention can be made of various combinations of a series of films and sheets, including aluminum foil, polyester film, nylon film, polyurethane film, polycarbonate film, polytetrafluoroethylene film, polyvinyl chloride film, polyvinylidine di-chloride film, acrylic ester film, polyethylene film, polypropylene film, acrylonitrile butadiene-styrene film, polyimide film, PolyethylenePropyleneDieneMonomer (EPDM) film, polychloroprene film, polysiloxane film, polyisoprene film, polyolefin film, ethylene-vinylacetate film, cellulosic film, woven and/or nonwoven fabrics and/or matting prepared from any or all of the above materials, and/or woven or nonwoven glass fabric or batting, polyamide foam, polyimid foam, polyester foam, polyethylene foam, polyurethane foam, polystyrene foam (Styrofoam), melamine foam, melamine-formaldahyde foam,

urea-formaldahyde foam, EthylenePropyleneDieneMonomer (EPDM) foam, Neoprene foam, Isopren foam, butylene foam, and other foam compositions.

The present multi-layer composite fire retardant material, which as herein illustrated comprises thermal insulation, may be prepared, as mentioned hereinbefore, using any or all of the aforementioned materials, as well as others which may be suitable depending on the given application or use of the composite material. Furthermore, the present composite material has any or all of its films or foil layers, constituting its multi-layered structure, coated with a fire retardant. The fire retardant coating which, in the composite material 10 of Fig. 1, is present on the central layer 12 and on the outside layers 20 may be either an intumescent and/or non-intumescent composition.

This multi-layer composite material provided on any of its layers with a fire retardant coating is used as a fire wall, fire block, fire barrier and/or thermal insulating membrane against the incursion of flame, heat, or fire.

Now referring to Fig. 2, there is shown a second multi-layer fire retardant material 30 constituted of a central layer 32, similar to central layer 12 of Fig. 1 and being constituted of a fibreglass saturated with a fire retardant, a pair of insulation layers 34, similar to insulation layers 14 of Fig. 1 and provided on the outer surfaces of the central layer 32, a pair of outer fire retardant fibreglass layers 36, similar to outside layers 20 of Fig. 1, a pair of aluminum foil films 38, similar to aluminum foil films 16 of Fig. 1, and a pair of outside polyester films 40, similar to polyester films 18 of Fig. 1.

Therefore, the multi-layer material 30 of Fig. 2 will provide higher reflectivity than the fire retardant material 10 of Fig. 1, while still embodying, albeit . internally, fire retardant layers. Indeed, in the fire

retardant material 10 of Fig. 1, the outside layers 20 include a fire retardant, whereas in the fire retardant material 30, the foil films 38 are not outwardly protected by a fire retardant but the overall composite material 30 still includes fire retardant layers 32 and 36 which are provided on the inside of the aluminum foil films 38.

Now turning to Fig. 3, a third multi-layer fire retardant material 50 also in accordance with the present invention is illustrated. This fire retardant material 50 comprises at least one central insulation layer 52, a pair of such central insulation layers 52 being herein shown, similar to insulation layers 14 of Fig. 1 but exempt of a fire retardant layer therebetween, and a pair of outside fire retardant layers 54 made, for instance, of a fibreglass coated with a fire retardant. In the composite material 50 of Fig. 3, there is no aluminum foil films and this material is more concerned with being an insulation provided with a flame barrier than with providing high reflectivity, as in the fire retardant material 30 of Fig. 2. Also, there could be a single fire retardant layer 54 mounted to a single central insulation layer 52.

Fig. 4 illustrates a fourth multi-layer fire retardant material 70 comprising a central aluminum foil film 72, a pair of polyester films 74 provided on the outside surfaces of the central aluminum foil films 72, a pair of insulation layers 76 provided on the outside surfaces of the polyester films 74, and a pair of outside fire retardant layers 78 made again, for instance, of fibreglass saturated with a fire retardant.

In Fig. 5, there is shown a fifth multi-layer fire retardant material 90 provided with a central fire retardant layer 92, a pair of insulation layers 94 provided on the outside surfaces of the central fire retardant layer 92, and a pair of outside fire retardant

layers 96 provided on the outer surfaces of the insulation layers 94.

When the composite material in accordance with the present invention is used, for instance, in a wall, light reflectivity is not a factor, but if energy remains a factor, then a laminated structure such as the composite material 10 of Fig. 1 would be suitable as, even though the reflective foil films 16 and their polyester films 18 are outwardly covered by the fire- retardant outside layers 20, the aluminum foil films 16 retain their ability to reflect energy. If the composite material requires light reflectivity, such as in arenas, then the layer arrangement of the composite material 30 of Fig. 2 is used. In applications where no reflectivity (i. e. energy-wise and light-wise) is required, the composite material requires, in addition to fire- retardant characteristics, insulative properties, and the composite materials 50 and 90 of Figs. 3 and 5, respectively, may be selected. When the composite material is used as a flame barrier, reflectivity may not be a factor and the material is used to stop the incursion of an impinging flame, whereas when it is used as an insulation, reflectivity is an important factor in preventing the underlying substrate from reaching its decomposition temperature.

The use of polyester films (e. g. as in the composite materials 10,30 and 70 of Figs. 1,2 and 4) over the aluminum foil layers or aluminized films causes the composite multi-layer material to have dielectric properties, and provides surface protection.

The insulation layers 14,34,52,76 and 94 of Figs. 1 to 5 respectively are made for instance of bubble-pack (or bubble wrap) and may be plain or contain fire retardant qualities. Bubble-pack insulation can be manufactured with a metallised polyester film. The above layers and films may be made obviously in varying thicknesses and weights, y as dictated by any particular

application or use of the resulting multi-layer fire retardant material.

"Bubble-pack"is a well-known material formed of two layers of plastic, typically such as low density polyethylene (LDPE), but also high density polyethylene (HDPE), PET, PVC, polypropylene, etc. One layer has an array of bulges formed therein, with all the bulges facing in a common direction. The other layer is sealed onto the first layer, on the side facing away from the bulges, thereby trapping air within the bulges.

There is great value in using bubble-pack in the present fire retardant laminates as, when subjected to heat, the bubble-pack layer melts and becomes an important fire retardant itself as the air bubbles are replaced by intumescence and it becomes a hard, fire retardant, plastic sheet. More details on the present laminate and its behaviour when subjected to heat follow hereinafter.

, The present invention, which utilizes the transformation of regular fiberglass material into a refractory silica together with metalized polyester and polyethylene bubble wrap after being exposed to heat, during which process an intumescent fire retardant is absorbed into the melt, has made it possible to combine it with a host of different substrate materials. This process creates a range of new fire retardant materials that are thin, flexible, water resistant or waterproof and as intumescent as needed.

By using the principle of KRONA Insulation Material, a metalized bubble wrap composite, that by itself is somewhat fire retardant but when subjected to fire will burn through, melt and drip, Applicants have developed the present fire-retardant insulation composite.

For instance in Fig. 1, the center layer of polyethylene has been replaced with a very lightweight glass fiber mat (veil) that is coated with an intumescent fire retardant. This coated material is then placed and laminated between the two layers of bubble wrap that are covered with a metalized polyester film on both the outsides, and they in turn are laminated between two outer layers of material that is also coated with an intumescent fire retardant. The coated material could be fiberglass, paper, basalt, cotton or synthetics, and the intumescent fire retardant could either be water-based or epoxy-based. The epoxy-based fire retardant, of course, provides more intumescence than the water-based coating.

The present fire-retardant material is an excellent, low cost and effective barrier against heat or cold, air and vapor which prevents drafts and problems caused by water condensation, and helps retain and

distribute heat within the concrete in radiant heat flooring systems.

Additional advantages of this material are its strength, its low di-electric nature (it is nonconductive), it is nontoxic, washable and environmentally friendly, meaning it does not require special handling or clothing when installed. The material is flexible, lightweight and can be shaped or cut with a utility knife or scissors and attached with nails, staples, tacks or glue.

When the outer layer of this new composite is exposed to a flame, the intumescent coating activates almost immediately and protects the fiberglass that under normal circumstances would melt through and disintegrate within two seconds. Now, the intumescence from the fire retardants combined with the melting fiberglass goes from an amorphous substance to a vitreous refractory silica that can withstand temperatures of about 4000 degrees Fahrenheit and the metalized polyester film on the bubble wrap as well as the polyethylene of the bubble wrap start softening and form a thin plastic sheet made up of both components. This sheet, again, does not melt, drip or burn and the intumescent carbon char (that forms when the fire retardant coating is subjected to a flame) scavenges the smoke that is so typical in a plastics fire while it filling up the void where the bubble wrap was, thus creating a protective layer between the flame and the substrate.

If a fire continues for an extended period of time, ultimately the center of the composite will heat up and intumesce while the fiberglass, polyethylene, polyester chemical reaction repeats itself and works its way to the other side of the composite.

. Depending on what the expected exposure to fire may be, the present composite could be built up to contain more layers of fire retardant coated materials.

Even so, it still will be many inches thinner than the conventional fiberglass or expanded polystryrene insulation.

This unique fire retardant system can be used in many applications: It is an excellent Fire Retardant insulation material that with. a quarter of an inch thickness is capable of providing, at least, an R-15 rating of insulation.

If more is needed, all that is required are additionally treated layers of the Composite.

Whether refurbishing old buildings or new ones, using the present composite not only o is Cost Effective because it is a low-cost insulation material; o it is Cost Effective because it is easy to install and repair; o it is Cost Effective because it prevents fire and consequently lowers the insurance risk; o it is clean, and o it improves one's surroundings in both hot and cold climates.

In the automotive industry, it could be applied under the headliners, floor boards, trunks and under the hood of cars, making them more sound proof and fire retardant at the same time while it would make an excellent fire wall between the

engine and the car's interior. Better insulation makes possible the use of smaller air conditioners, thus reducing the weight and expense of cars.

In public transportation such as on trains and buses, it would add considerably to the safety of its passengers. For instance in case of a car crash where a pool fire occurs, the passengers will be protected.

For aerospace, fire retardant insulation in the cargo bay, around the cabin as well as in the belly of airplanes is very important and the present laminate could add a high degree of safety to the aircraft and its occupants. Weight is of utmost importance in airplanes as well as in shipbuilding. It can be used to insulate the hull as well as other areas of ships. Again, better insulation improves performance through weight reduction.

In certain fire situations such as Forest Fires, a blanket made of the present laminate could be used as a shield against the flames during escape.

Uses for this material in the Oil Industry where fires are often too hot to approach, it could provide a life saving shield for escape or provide a barrier to curb spread of a fire.