INSULATION SHEETING

FIELD OF INVENTION

The present invention relates to insulation sheeting and has particular but not exclusive application for insulating buildings and other structures.

BACKGROUND OF THE INVENTION

Insulation sheeting having a plastic bubble layer and outer reflective foil layers has been used to insulate buildings. The plastic bubble layer serves to reduce the amount of heat transferred from one side to the other. The reflective foil layer serves to reflect heat from the surface thereby preventing transmission of the heat.

An example of reflective foil insulation sheeting has been described in Australian innovation patent 200410339. The reflective foil insulation sheeting of Australian innovation patent 200410339 has a layer of scrim bonded to the foil layer. Scrim is a woven layer of material and is expensive to manufacture. The scrim layer provides support for the aluminum foil during the manufacture of the foil layer. The resultant foil layer has a plurality of dimples formed between the weave during manufacture. The dimpled foil layer however, is less efficient in reflecting heat than a non-dimpled foil layer. The loss in the ability to reflect heat and the comparatively high cost of scrim is a disadvantage in providing efficient and affordable insulation sheeting.

OBJECT OF THE INVENTION

It is an object of the present invention is to provide an alternative insulation sheeting that overcomes at least in part one or more of the above mentioned problems.

SUMMARY OF THE INVENTION

In one aspect the present invention broadly resides in insulation sheeting including a first polyethylene layer; one or more closed air cell layers disposed adjacent the first polyethylene layer; a second polyethylene layer disposed adjacent the closed air cell layer and located on an opposite side of the closed air cell layer relative to the first polyethylene layer; a reflective layer disposed adjacent the second polyethylene layer, wherein the reflective layer includes a plurality of substantially parallel elongate members to support the reflective layer during manufacture.

In a further aspect the present invention broadly resides in insulation sheeting including a first polyethylene layer; one or more closed air cell layers disposed adjacent the first polyethylene layer;

a second polyethylene layer disposed adjacent the closed air cell layer and located on an opposite side of the closed air cell layer relative to the first polyethylene layer; a reflective layer disposed adjacent the second polyethylene layer; and an outer protective layer disposed adjacent the reflective layer, wherein the reflective layer includes a plurality of substantially parallel elongate members to support the reflective layer during manufacture.

In another aspect the present invention broadly resides in insulation sheeting including a first reflective layer; a first polyethylene layer disposed adjacent the first reflective layer; one or more closed air cell layers disposed adjacent the first polyethylene layer; a second polyethylene layer disposed adjacent the closed air cell layer and located on an opposite side of the closed air cell layer relative to the first polyethylene layer; a second reflective layer disposed adjacent the second polyethylene layer; and an outer protective layer disposed adjacent the second reflective layer, wherein each of the first and second reflective layers includes a plurality of substantially parallel elongate members to support the reflective layer during manufacture.

The reflective layer is preferably a metal foil layer or a metalised polyester layer. The metal foil layer is preferably an aluminium foil layer.

The closed air cell layer is preferably a layer that contains air pockets or bubbles produced from polyethylene. More preferably, the closer air cell layer has bubbles formed by polyethylene and the bubbles are covered by a top polyethylene layer and a base polyethylene layer. The plurality of substantially parallel elongate members is preferably a series of parallel strings. The strings may consist of synthetic or natural fiber. The synthetic fiber may be fiberglass or nylon. The natural fiber may be rice husk fiber or other natural materials.

Each of the first polyethylene layer and the second polyethylene layer preferably includes a relatively thick polyethylene layer that combines the sub-layers of a polyethylene tie layer and a polyethylene layer. Preferably, each of the first polyethylene layer and the second polyethylene layer is between 10 to 60 microns.

Each of the first polyethylene layer and the second polyethylene layer preferably includes a fire retardant. The closed air cell layer preferably includes a fire retardant. The fire retardant may be a halogen fire retardant but is preferably of a non halogen nature.

Preferably, each of the first polyethylene layer and the second polyethylene layer includes a mould inhibitor. The closed air cell layer preferably also includes a mould inhibitor. More preferably, each of the first polyethylene layer and the second polyethylene layer includes the fire retardant and the mould inhibitor.

The first polyethylene layer, the second polyethylene layer or the closed air cell layer preferably include a fire retardant and or a mould inhibitor.

The closed air cell layer, the first polyethylene layer and the second polyethylene layer are preferably produced from low density polyethylene.

The bubbles of the closed air cell layer preferably have a diameter between about 5 mm and 40 mm and a depth between about 1 mm and 15 mm.

In a preferred embodiment, the bubbles have a diameter between 22 mm and 35 mm and a depth between 8 mm and 15 mm. More preferably the bubbles have a diameter of approximately 32 mm and a depth of approximately 12 mm.

In an alternative embodiment, the bubbles have a diameter of about 20 mm and a depth of about 6 mm.

The outer protective layer is preferably impermeable to prevent the second reflective layer from oxidizing. The outer protective layer is preferably impermeable to oxygen or corrosive residues. Preferably, the outer protective layer is a plastic layer or of other barrier material.

The outer protective layer may contain a colouring agent to assist in the reduction of glare reflected from a top side of the second reflective layer.

The second reflective layer preferably has a lower side that is made less reflective to absorb more heat for dissipation.

Preferably, the insulation sheeting has a thickness between 2mm and 15mm.

More preferably, the insulation sheeting has a thickness of about 13.4 mm with a single layer of air cell bubbles having a 12mm depth.

The above mentioned insulation sheeting may include a foam layer. The foam layer is preferably a layer of low density polyethylene or low density polypropylene micro-cell foam.

Preferably, the foam layer has a thickness of between 2 mm and 20 mm.

The foam layer preferably includes the above mentioned fire retardant and or the mould inhibitor.

The foam layer is preferably of low density polyethylene or low density polypropylene micro-cell foam and the foam layer is disposed between the one or more closed air cell layer and the first polyethylene layer or second polyethylene layer. In one embodiment, there is a single foam layer disposed between the one or more closed air cell layers and the first polyethylene layer.

In another embodiment, there is a single foam layer disposed between the one or more closed air cell layer and the second polyethylene layer.

In yet another embodiment, there is a first foam layer disposed between the one or more closed air cell layers and the first polyethylene layer, and a second foam layer disposed between the one or more closed air cell layers and the second polyethylene layer.

In the embodiments where there is a single foam layer, the single foam layer is preferably between 2 and 10 mm thick. In the embodiment where there are two foam layers, each of the foam layers is preferably between 1 and 5 mm thick.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the present invention can be more readily understood reference will now be made to the accompanying drawings which illustrate preferred embodiments of the invention and wherein:

Figure 1 is a schematic diagram of a first embodiment of the insulation sheeting; and

Figure 2 is a schematic diagram of a second embodiment of the insulation sheeting.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to Figure 1 there is shown a first embodiment of the insulation sheeting 10 having a series of sequential layers consisting of a lower aluminum foil layer 11 , a lower polyethylene layer 12, a single closed air cell layer 13, an upper polyethylene layer 14, an upper aluminum foil layer 15 and an outer protective plastic layer 16.

The lower and upper aluminum foil layers 11 , 15 have a series of parallel strings that support the aluminum foil layers during manufacture. As the strings do not intersect, dimples in the foil layer are not formed during manufacture. As a consequence, the reflectivity of the aluminum foil layer is better than a foil layer with scrim.

The strings are made from either fiberglass, nylon or rice husk fibers. The upper aluminum foil layer 15 has a top side and a bottom side. The top side faces outwards when the insulation sheeting 10 is installed in a building while the bottom side faces inwards toward the interior of the building. The bottom side is made less reflective so that more radiant heat is absorbed from the interior of the building and dissipated to the exterior of the building rather than being reflected back into the interior of the building. The lower and upper polyethylene layers 12, 14, respectively, are made of low density polyethylene. Each of the polyethylene layers 12, 14 has a thickness between 10 and 60 microns but preferably about 25 to 30 microns and includes both a non-halogen or halogen fire retardant and preferably a mould inhibitor.

The closed air cell layer 13 comprises a single layer of bubbles 17 that is covered by a top layer 18 and a base layer 19. The bubbles 17, top layer 18 and

base layer 19 are all produced from low density polyethylene. The top polyethylene layer 18 is located between the bubbles 17 and the upper polyethylene layer 14 while the base polyethylene layer 19 is located between the bubbles 17 and the lower polyethylene layer 12. The bubbles have a diameter of about 32 mm and a depth of about 12 mm.

The outer protective plastic layer 16 is impermeable to oxygen and corrosive residues and prevents the surface of the top side of the upper aluminum foil layer 15 from weathering. The outer protective plastic layer 16 has a green color to assist in the reduction of glare reflected from a top side of the upper aluminum foil layer 15. The thickness of the insulation sheeting 10 is about 13.4 mm.

With reference to Figure 2, there is shown a second embodiment of the insulation sheeting 30. The insulation sheeting 30 has a series of sequential layers consisting of a lower aluminum foil layer 31 , a lower polyethylene layer 32, a lower foam layer 33, a single closed air cell layer 34, an upper foam layer 35, an upper polyethylene layer 36, an upper aluminum foil layer 37 and an outer protective plastic layer 38. The insulation sheeting 30 is similar to the insulation sheeting 10 described above, except that insulation sheeting 30 has the two foam layers 33, 35. The foam layers 33, 35 provide further insulation and also provide acoustic insulation.

The lower foam layer 33 is located between the closed air cell layer 34 and the lower polyethylene layer 32. The upper foam layer 35 is located between the closed air cell layer 34 and the upper polyethylene layer 36. Each of the foam layer 33, 35 is about 2 mm thick and is made of a low density polyethylene. Low density polypropylene micro-cell foam may alternately be used. The foam layers 33, 35 include both a non-halogen or halogen fire retardant and may include a mould inhibitor.

ADVANTAGES

An advantage of the preferred embodiment of the insulation sheeting includes having layer(s) of aluminum foil or other reflective material with a series of parallel strings thereby avoiding the use of scrim and inheriting the associated problems. The parallel strings can be manufactured from fiberglass, nylon or be derived from natural fibers such as rice husk fiber. A non-woven scrim layer is relatively quicker to manufacture and laminates better.

A further advantage of the preferred embodiment of the insulation sheeting is that the mould inhibitor in the insulation sheeting reduces the growth of moulds in the insulation sheeting. Prevention of the growth of moulds is particularly advantageous in the more humid environment of tropical climates.

Another advantage of the preferred embodiment of the insulation sheeting is that the fire retardant in the insulation sheeting is of a non halogen nature and therefore is non toxic.

VARIATIONS

It will of course be realised that while the foregoing has been given by way of illustrative example of this invention, all such and other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as is herein set forth.

Throughout the description and claims this specification the word "comprise" and variations of that word such as "comprises" and "comprising", are not intended to exclude other additives, components, integers or steps.