AU2019279899A1

AU2019279899A1 - Developments in perforated sheeting

Info

Publication number: AU2019279899A1
Application number: AU2019279899A
Authority: AU
Inventors: Keith Robert Anderson; Scott Ian Gibson
Original assignee: Kingspan Insulation Pty Ltd
Current assignee: Kingspan Insulation Pty Ltd
Priority date: 2014-04-08
Filing date: 2019-12-09
Publication date: 2020-01-02
Also published as: WO2015154128A1; AU2015245930A1; AU2015245930B2

Abstract

Abstract According to the present invention there is provided an insulation sheet material comprising a body (10) having a pair of opposed surfaces (11, 12), the body (10) comprising a cell structure (13), the body (10) being perforated (27) with a plurality of tapered perforations extending substantially perpendicularly with respect to each said opposed surface; and throughout the insulating material, thereby to provide for relatively enhanced water vapour transfer (WVT) relative to an equivalent material having non-tapered perforations.

Description

DEVELOPMENTS IN PERFORATED SHEETING

Related Application

This application claims the benefit of Australian provisional patent application AU 2014901279, filed on 8 April 2014; the content of the provisional specification is incorporated herein by reference in its entirety.

Field of the Invention

The present invention relates to insulation materials - and more particularly, to vapour-permeable insulating sheeting for use within walls with cavities. The invention has been devised particularly, although not necessarily solely, for insulating buildings and other structures. However, those skilled in the art will appreciate that the invention is not necessarily limited to this particular field of use.

The present invention also relates to a method and apparatus for manufacturing such insulating materials.

Background of the Invention

Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.

The majority of insulation in buildings is for thermal purposes. However, the general term “insulation” also applies to acoustics, fire, and impact insulation. Often an insulating material will be chosen for its ability to perform several of these functions at once.

Thermal insulation is the reduction of heat transfer (i.e., the transfer of thermal energy between objects of differing temperature) between objects in thermal contact or in range of radiative influence. Thermal insulation can be achieved with specially engineered methods or processes, as well as with suitable object shapes and materials. Heat flow is an inevitable consequence of contact between objects of differing temperature. Thermal insulation provides a region of insulation in which thermal conduction is reduced or thermal radiation is reflected rather than absorbed by the lower-temperature body.

In colloquial terms, “thermal insulation” refers to a building’s capacity to stay cool in the summer and warm in the winter. Maintaining acceptable temperatures in buildings

-2(by heating and cooling) uses a large proportion of global energy consumption. When well insulated, a building is relatively energy-efficient (thus saving the owner money), provides relatively uniform temperatures throughout the space (i.e., there is less temperature gradient both vertically and horizontally from exterior walls, ceilings and windows to the interior walls, thus producing a more comfortable occupant environment when outside temperatures are extremely cold or hot), has relatively reduced recurring expense (such that unlike heating and cooling equipment, insulation is permanent and does not require maintenance, upkeep, or adjustment) and lowers the Tripton rating of the carbon footprint produced by the building. A well insulated building is thereby appreciably “clean and green”.

As such, both commercial and residential buildings are typically insulated with materials that may provide for relatively optimal heat flow characteristics by comparison with an equivalent non-insulated building. This is particularly true in these times of everincreasing environmental consciousness.

The insulating capability of a material is expressed in terms of its thermal conductivity (k). Low thermal conductivity is equivalent to high insulating capability (Rvalue). In thermal engineering, other important properties of insulating materials are product density (p) and specific heat capacity (c).

There are various types of insulation commercially available for buildings, including thermo-reflective insulation sheeting. An example of such sheeting is disclosed in the Applicant’s now expired Australian innovation patent, AU 2003100663. Such insulation sheeting comprises a single layer closed cell structure interposed between two outer layers, at least one of which comprises a reflective foil. This insulation sheeting has proved to be a particularly effective barrier in reducing heat energy transfer; the closed air cell structure serves to reduce the amount of heat transfer through convection and conduction, and the reflective layer serves to reduce heat transfer through radiation. However, in addition to providing a barrier to heat transfer, this insulation sheeting also provides a barrier to vapour transfer, which can result in “suffocation” (i.e., the nonbreathability of the material, as opposed to suffocation, per se) and/or condensation. Condensation can give rise to undesirable situations such as mould, odour and rot - and also affects the heat transfer profile of the insulating material such that the thermal performance of water droplets is somewhat inefficient.

As thermal performance requirements for building fabric continue to rise,

-3condensation is becoming an increasingly important design consideration for functional (healthy) buildings. Where insulation sheeting is intended to be installed in walls and floors, it is desirable that the sheeting have some permeability to moisture vapour so as to reduce the risk of damage due to condensation in the building envelope cavity. This is especially true of buildings housing ducted air conditioning within the ceiling cavity, where additional heat and vapour considerations may be applicable.

In order to address the industry-wide desire for a vapour-permeable insulating sheet, the present Applicant developed the commercial product known as Permicav®, which is available as Permiwall® (see, e.g., http://www.kingspaninsulation.com.au/ products/kingspan-air-cell/air-cell-permiwall/overview.aspx), Permifloor® and Permishield®. The Permicav® suite of products has been sold in Australia and indeed throughout the world since 2006 - and is covered by patents such as AU 2012241111 and AU 2015201356. In the ensuing description, for comparative purposes, Permicav® and Permiwall® are used synonymously.

Permicav® has been shown to reduce the risk of interstitial condensation by allowing vapour to permeate through tiny perforations between the outer layers. Permicav® generally comprises a cross-linked, closed-cell foam core sandwiched with an anti-glare foil facing on one side and a plain foil facing on the other side. A series of regular perforations extend between the anti-glare and plain foil facings so as to provide a series of conduits through which vapour can permeate. It will be appreciated that such vapour permeability reduces the risks of an insulated building suffering from interstitial condensation. Moreover, because the perforations are generally very small (~0.2 mm diameter), only a small drop in thermal performance is experienced by comparison with the “equivalent” non-perforated material.

Marketed as a vapour-permeable insulation material for walls with cavities, Permicav® provides for a “3-in-l” insulation, vapour-permeable membrane and radiant barrier. It is a thin (-4-6 mm) sheet material compliant with AS/NZS national Standards (including, for example, 4201.3, 4859.1, 1530.2 and 4201.6) - and is certified for BCA compliance.

As mentioned, Permicav® comprises a body having two outer layers with a cell structure bonded therebetween. Each outer layer has an outer surface. The body is of a thickness between the outer surfaces which allows the insulation sheeting to be disposed in a rolled configuration for storage/transportation and then unrolled to assume a substantially

-4flat configuration in use. The perforations typically comprise a plurality of regularlyshaped openings extending through the body and opening onto the opposed surfaces thereof. In an embodiment, the plastic membranes used in the formation of the closed cell structure are typically comprised of low-density polyethylene (LDPE), high density polyethylene (HDPE), or linear low-density polyethylene (LLDPE). Preferably, the membrane thickness is about 175 pm or smaller. The single layer cell structure preferably comprises a plurality of cells of generally cylindrical construction, each of a diameter between about 8 mm and 25 mm, and a depth of between about 3 mm and 10 mm. Preferably, the diameter of each cell is about 10 mm. Preferably, the thickness of the sheeting between the two opposed surfaces is about 4 mm, in which case the depth of each cell would be about 3 mm.

Permicav® is designed specifically for walls with cavities to reduce the risk of condensation. A patented (see, e.g., AU 2012241111) closed-cell structure sandwiched by highly reflective foil surfaces and pierced with tiny, evenly-spaced perforations, Permicav® allows water vapour permeability while helping to achieve a 6-star house energy rating. Another advantage realised by Permicav® is that due to its minimal thickness, wall cavities remain unfilled and accessible for services.

Permicav®, despite having enjoyed considerable commercial success since its launch in 2006, must be critiqued against an ever-evolving commercial and technical landscape as it relates to insulating materials. To this end, Permicav® provides a level of water vapour transmission (“WVT”) classified as “medium” (i.e., medium resistance to WVT by test method ASTM E96), which is suitable for many wall insulation configurations. However, as insulation requirements have increased (for instance, more insulation is being used in the construction of new buildings for energy-efficiency reasons - and many existing buildings are being re-insulated for the same reasons), there is attendant increased concern about condensation within wall cavities; this is especially true of older, wooden buildings in which interstitial rot can be a considerable problem. Accordingly, an increased level of WVT compared with that provided by Permicav® is now more commonly desirable in order to prevent excessive condensation developing.

It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

Accordingly, it is an object of an especially preferred form of the present invention to provide for an inventive concept that could give rise to a commercially-applicable

-5product sharing substantially the energy transmission profile and convenience of Permicav® - and yet providing for a relatively improved WVT profile. It will be appreciated that any such material could then be amenable to use within a relatively heavily insulated building in relatively humid or high-condensation environments, at once providing for increased energy efficiency (i.e., a favourable “green” profile), without the attendant and undesirable risk of increased condensation, mould, mildew, odour and rot.

It will be further appreciated that an improved WVT profile is not simply a matter of making larger perforations in the existing Permicav® material. Larger perforations of course detract from thermal performance, ultimately requiring more insulating material (i.e., a thicker product) to be used in order to achieve the same thermal profile. Rather, an improved insulating material should ideally have substantially all the thermal and practical advantages found in Permicav® - but with an improved WVT profile relative to Permicav®.

Throughout the description and claims, the term “tapered” refers to the general proposition that an insulating material is perforated with a cavity extending between the opposed faces of the material - and that one of the openings is larger than the other. Within the bounds of “tapered” is a regular taper, whereby the larger basal opening tapers to the smaller apical opening in a regular/consistent manner (e.g., conical). However, also within the bounds of “tapered” are irregular tapers, for instance, where angles, internal curvature and the like are not necessarily consistent. As mentioned, the general principle is that the “apical” (as in, the apex of a triangle) opening is smaller than the “basal” (as in, the base of a triangle) opening. It will be appreciated that the “classic” tapered shape as depicted according to Figure 1(a) is frustro-conical. However, as per Figure 1(b) to Figure 1(e) any passage having one opening larger than the other is technically “tapered” for the purposes of the present invention.

Furthermore, as will be appreciated by those skilled in the art, the term “opening”, when viewed in the context of a perforation in a somewhat resilient foam/foil insulating material, is unlikely to be strictly regular in shape, even when made with a regularlyshaped perforating tool. To some extent the resilient material through which the perforation is made will relax, meaning that the precise shape of the opening (at the basal and/or apical end) is not necessarily regular or circular - it may be oblong, rectangular, rhomboid, square - essentially any geometrical shape whilst keeping with the tenor of the present invention.

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Further, the term “perforated” need not refer exclusively to a material having been perforated by a tool, it can refer also to a material so-formed by, for instance, injection moulding. The means by which the tapered perforations are placed in the insulating material are secondary to the concept of the tapered perforations themselves.

Further, the term “diameter”, although correctly referring to circles, is intended to also encompass the span (any span, not necessarily the largest dimension) of any geometrical shape. For instance, as mentioned elsewhere, even when punched with a regular/circular perforating tool, an opening will tend to “relax” given the resilience typically characterising foam insulating materials - and the circular/regular shape can thereby become irregular. Therefore, within the spirit of the invention, “diameter” is used to define the span of any such irregular shape. However, in a preferred embodiment, a circular perforating tool gives rise to a substantially circular opening, making “diameter” a convenient and well understood (to the person skilled in the art) term.

Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”.

Although the invention will be described with reference to specific examples it will be appreciated by those skilled in the art that the invention may be embodied in many other 20 forms.

Summary of the Invention

In general terms, the present invention resides in the surprising discovery that in an insulating material, tapered perforations provide for a WVT profile that can be classified as 25 “low” (i.e., low resistance to WVT as classified by AS/NZS 4200.1:1994 and tested to test method ASTM E96) - and is thereby suitable for a wide variety of in-wall applications. The tapered perforation has enough structural integrity not to bend or break in service; the fine perforation is required to maintain the water barrier and air barrier properties.

Thus, according to a first aspect of the present invention there is provided a method of providing for water vapour transfer through an insulation material, said method comprising providing one or more continuous perforation/s through said insulating material, said perforations being tapered such that for each said perforation an entry opening is of substantially different size to its corresponding exit opening. In this respect,

2019279899 09 Dec 2019

-7“size” is akin to “area” of the opening.

In a preferred embodiment, the method comprises providing a plurality of the continuous tapered perforations in an insulating sheet material.

In a preferred embodiment, said entry opening and its corresponding exit opening are, on average throughout the plurality of perforations, in an approximate size (area) ratio of between about 100:1 to about 1.1:1. More preferably, said ratio is between about 20:1 and about 2:1. More preferably still, said ratio is between about 10:1 and about 3:1. Even more preferably, said ratio is between about 7:1 and about 4:1. Even more preferably still, said ratio is between about 6:1 and about 4.5:1. Most preferably, said ratio is about 5:1.

In an embodiment, said entry opening has on average throughout the one or more perforations, a span of between about 0.1 mm and about 5.0 mm. Preferably, said entry opening has a span of between about 0.2 mm and about 3.0 mm. More preferably, said entry opening has a span of between about 0.3 mm and about 1.5 mm. More preferably still, said entry opening has a span of between about 0.35 mm and about 1.0 mm. Even more preferably, said entry opening has a span of between about 0.4 mm and about 0.8 mm. Yet more preferably, said entry opening has a span of between about 0.45 mm and about 0.6 mm. Most preferably, said entry opening has a span of about 0.5 mm.

In a preferred embodiment, said one or more perforations is provided in said insulating material either substantially continuously via a roller-type process; or batch-wise via a stamp-like process. In an embodiment, said roller-type process and/or said stamplike process are calibrated to ensure that each perforation is made through said insulating material to a predetermined depth, thereby to provide for exit and entry openings of predetermined sizes (areas) within the insulating material.

In an embodiment, the predetermined size of said entry opening is about 0.5 mm and the predetermined size of said exit opening is about 0.1 mm.

Preferably, said roller-type process comprises a plurality of tapered perforating pins arranged in an array at predetermined intervals about the circumference of said roller, each said pin disposed substantially radially outwards, wherein in order to effect said substantially continuous method, said insulating material is brought into perforating engagement with said perforating pins such that when said insulating material is moved with respect to said roller (or vice versa), said roller rotates to thereby perforate successive areas of said insulating material in a substantially continuous manner.

In another embodiment, said stamp-like process comprises a plurality of tapered

-8perforating pins arranged in an array at predetermined intervals over a face of a stamping plate, each said pin disposed substantially outwards from the surface of said plate, wherein in order to effect said batch-wise method, said insulating material is brought into perforating engagement with said plate (or vice versa), thereby to effect one stamping batch; and wherein following said stamping batch, said plate is removed from said perforating engagement, and optionally a further area of insulating material is brought into perforating engagement with said plate, to thereby perforate successive areas of said insulating material in a batch-wise manner.

According to a second aspect of the present invention there is provided an insulation material comprising a body having a pair of opposed faces, the body comprising a cell structure, the material further comprising one or more tapered perforations extending between and through said opposed faces to define an entry opening of larger size than its respective exit opening. In this respect, “size” is akin to “area” of the opening.

In a preferred embodiment, the insulating material comprises a plurality of the continuous tapered perforations.

In a preferred embodiment, the cell structure comprises a closed cell structure. Preferably, the cell structure comprises a single layer cell structure. More preferably, the single layer cell structure comprises a plurality of plastic membranes bonded together to form a plurality of air cells therebetween. More preferably still, the closed cell structure comprises a closed cell foam structure.

In a particularly preferred embodiment, the closed cell foam structure comprises polyethylene foam, polypropylene foam or any other applicable foam or combination thereof. Preferably, the closed cell foam structure comprises cross-linked low density polyethylene (LDPE) foam.

In another embodiment, the body further comprises an outer layer adjacent the cell structure, the outer layers defining one of the opposed surfaces.

In another embodiment, the body further comprises two outer layers between which the cell structure is disposed, the outer layers defining the respective opposed surfaces. Preferably, at least one of the outer layers comprises a foil.

In another embodiment, the cell structure defines at least one of the opposed surfaces of the body.

In a preferred embodiment, the tapered perforations are formed after construction of the insulation material. Preferably, the tapered perforations are generated by perforating

-92019279899 09 Dec 2019 the material in a substantially continuous or batch-wise manner by an apparatus adapted for imparting said tapered perforations within said insulation material.

In an embodiment, said entry opening and its corresponding exit opening are, on average throughout the one or more perforations, in an approximate size (area) ratio of between about 100:1 to about 1.1:1. Preferably, said ratio is between about 20:1 and about 2:1. More preferably, said ratio is between about 10:1 and about 3:1. More preferably still, said ratio is between about 7:1 and about 4:1. Even more preferably, said ratio is between about 6:1 and about 4.5:1. Most preferably, said ratio is about 5:1.

In an embodiment, said one or more perforation/s are spaced apart in a generally regular arrangement. Preferably, said plurality of perforations is spaced apart by about 0.5 mm to about 5.0 mm. More preferably, said plurality of perforations is spaced apart by 20 about 1.0 mm to about 4.0 mm. More preferably still, said plurality of perforations is spaced apart by about 1.5 mm to about 3.0 mm. Even more preferably, said plurality of perforations is spaced apart by about 2.0 mm to about 2.5 mm.

In another preferred embodiment, said material is between about 3.0 mm and about 7.0 mm in thickness. Preferably, said material is between about 4.0 mm and about 6.0 mm 25 in thickness. More preferably, said material is about 5.5 mm in thickness. Most preferably, said material is about 5.0 mm in thickness.

In an especially preferred embodiment of the present invention, said body is foam such as cross-linked LDPE foam; said opposed faces are comprised of aluminium foil (reflective and/or anti-glare); and wherein the ratio of said entry to said exit openings is 30 about 5:1; wherein the span of said entry hole is approximately 0.5 mm; wherein said plurality of perforations are spaced generally regularly at intervals of about 2.5 mm; wherein said insulating material is about 5 mm in thickness; and wherein said entry and exit openings are generally circular.

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In an embodiment, one of the outer layers has a reflective finish; and the other outer layer has an anti-glare finish. Preferably, said entry openings are made in said anti-glare outer layer; and wherein said exit openings made in said reflective outer layer.

In an especially preferred embodiment, when installed in use within an interstitial cavity of a building, the anti-glare outer layer comprising the plurality of entry openings is disposed toward the exterior of the building; and the reflective outer layer comprising the plurality of plurality of entry openings is disposed toward the interior of the building.

In another preferred embodiment, said perforated insulating material is in the form of a continuous rolled sheet.

According to a third aspect of the present invention there is provided in a sheet-like insulating material having a plurality of perforations extending therethrough, an improvement consisting in tapered perforations so as to provide for a relatively improved water vapour transfer (WVT) profile relative to an otherwise identical material having a corresponding plurality of non-tapered perforations.

According to a fourth aspect of the present invention there is provided a method of perforating a sheet of insulating material with a plurality of tapered perforations via a substantially continuous process, said method comprising the steps of providing a rollertype arrangement calibrated to ensure that each perforation is made through said insulating material to a predetermined depth, thereby to provide for exit and entry openings of predetermined sizes within the insulating material, wherein said roller-type arrangement comprises a plurality of tapered perforating pins arranged at predetermined intervals around the circumference of said roller, each said pin disposed substantially radially outwards, wherein in order to effect said substantially continuous method, said insulating material is brought into perforating engagement with said roller such that when said insulating material is moved with respect to said roller (or vice versa), said roller turns to thereby perforate successive areas of said insulating material.

According to a fifth aspect of the present invention there is provided an insulating material perforated with a plurality of tapered perforations, when perforated by a substantially continuous method as defined according to the fourth aspect of the present invention.

According to a sixth aspect of the present invention there is provided a method of perforating a sheet of insulating material with a plurality of tapered perforations via a batch-like process, said method comprising the steps of providing a stamper calibrated to

- 11 ensure that each perforation is made through said insulating material to a predetermined depth, thereby to provide for exit and entry openings of predetermined sizes within the insulating material, wherein the stamper comprises a plurality of tapered perforating pins arranged at predetermined intervals over a face of a stamping plate, each said pin disposed substantially outwards from the surface of said plate, wherein in order to effect said batchwise method, said insulating material is brought into perforating engagement with said plate, thereby to effect one stamping batch; and wherein following one said stamping batch, said plate is removed from said perforating engagement, and optionally a further area of non-perforated insulating material is brought into perforating engagement with said plate, thereby to effect said batch-wise perforating.

According to a seventh aspect of the present invention there is provided an insulating material perforated with a plurality of tapered perforations, when perforated by a batch-wise method as defined according to the sixth aspect of the present invention.

According to an eighth aspect of the present invention there is provided a method for providing relatively optimised water vapour transfer (WVT) through a sheeted insulating material disposed within interstitial cavities of a building, said method comprising the step of providing said insulating material with a plurality of tapered perforations extending between the respective opposed surfaces of said sheeted insulating material such that said water vapour is selectively permeable through said perforations, thereby to reduce risk of condensation within said cavities.

According to a ninth aspect of the present invention there is provided a kit for onthe-shelf sale, the kit comprising an insulating material as defined according to the second aspect of the present invention; and at least one ancillary article selected from: at least one spacer biscuit; at least one wall tie; at least one roll of reinforced foil ducting tape for binding adjacent sheets in use; at least one knife; and a set of instructions.

Brief Description of the Drawings

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 7 is a representative depiction of the term “tapered” as it pertains to the present invention. Specifically, a “tapered” perforation is one in the opening at one end is larger than the opening at the other - for instance, a truncated cone. However, neither the openings nor the continuous conduit therebetween need by regular; any configuration

- 12providing for a relatively large opening and a relatively small opening is “tapered” according to the present invention. Thus, Figure 1(a) depicts a classical truncated cone (“traffic cone”) taper; Figure 1(b) shows the apical and basal openings offset slightly from each other; Figure 1(c) depicts an irregular taper in which the conduit is skewed on one side relative to the other; Figure 1(d) shows a rectangular tapered perforation; and Figure 1(e) shows a “real life” instance in which following perforation, the resilient foam through which the perforation is made relaxes somewhat, giving rise to irregular shapes at the apical and/or basal openings. It will be appreciated that Figures 1(a) to 1(e) are exemplary only, non-exhaustive and non-limiting.

Figure 2 is a schematic view of insulation sheeting according to a first embodiment (i.e., the “open cell” structure), with part of an outer layer of the sheeting removed to reveal the cellular “open” structure. The perforations on one face (25) are clearly visible and each perforation protrudes through the body (10) in a tapered manner (e.g., Figures 1(a) to 1(e), above);

Figure 3 is a cross-section along the line 2-2 of Figure 2. The tapered perforations (25) extend through the top layer, through the air cell (1) and out the bottom layer. It will be appreciated that such an arrangement provides for a tapered conduit of the type depicted generally in Figure 1(c), above;

Figure 4 is an exploded selection of Figure 3 in which the tapered perforations (25) are clearly discernible.

Figure 5 is a schematic view of part of the cellular structure;

Figure 6 is a schematic perspective view of the insulation sheeting of the second embodiment of the invention, with several layers partly removed to reveal the internal construction;

Figure 7 is a schematic fragmentary elevational view of insulation sheeting according to a third embodiment, with part of an outer layer of the sheeting removed to reveal the inner closed cell foam structure;

Figure 8 is a fragmentary side elevational view of the insulation sheeting of Figure 7, in which the tapered perforations are clearly discernible;

Figure 9 is a plot for Permicav® showing that that the temperature profile/sample condensation assessment of a system, represented by the solid line (T), does not drop below dewpoint temperature, represented by the dotted line (D), indicating that condensation will not occur in this system in this particular location (i.e., a double brick

- 13 cavity wall in Perth, WA (BCA Climate Zone 5) performed in accordance with ISO 13788:2001. These data, being essentially comparative data for Permicav® are significant insofar as the performance of the improved “tapered” product has been shown empirically elsewhere to be around 5 times that of Permicav®;

Figure 10 plots comparative water vapour transmission (WVT) data for a) brick; b) Permiwall® sans any perforations; c) Permiwall®; and d) a material according to the invention which is otherwise identical to Permiwall®, but embodies tapered rather than regular perforations. According to the quantitative data, the inventive material exhibits up to five times better WVT profile than does Permiwall®;

Figure 77 is a photograph of a prototype “tapered” product in accordance with the invention; an approximate 7x7 cm area is shown. The photograph shows the anti-glare facing dotted with a plurality of “entry” perforations at a spacing of approximately 2.5 mm apart. In use, the anti-glare facing comprising the relatively large entry perforations is disposed toward the exterior of the building in which it is installed; and

Figure 12 is a photograph of a prototype “tapered” product in accordance with the invention; an approximate 7x7 cm area is shown. The photograph shows the thermoreflective foil facing dotted with a plurality of “exit” perforations approximately 1/5 the size of the “entry” perforations depicted in Figure 11. In use, the reflective facing comprising the relatively small exit perforations is disposed toward the interior of the building in which it is installed. In the embodiments depicted by Figure 11 and Figure 12, the body is comprised of a closed cell foam such as cross-linked LDPE foam; the opposed faces are comprised of aluminium foil (one is anti-glare, the other thermo-reflective aluminium foil); the ratio of said entry to said exit openings is approximately 5:1; the span of said entry openings is approximately 0.5 mm; the plurality of perforations are spaced generally regularly at intervals of about 2.5 mm; the insulating material is about 5 mm in thickness; and the entry and exit openings are generally circular when made. However, given that the LDPE or other foam from which the material is made is somewhat resilient, the generally circular entry and exit openings (and the continuous conduit therebetween) will likely relax somewhat (see, e.g., Figure 1(e)).

Examples

In providing comparative basis for the present invention, it was thought appropriate to compare the WVT profile of the inventive “tapered” material with that of the

- 14Applicant’s own commercial product, Permicav® (embodied as Permiwall®). In general, Permicav® is found to give rise to a temperature profile that does not drop below the dew point temperature for a given application. Permicav® is installed in the cavity of a wall and effectively divides that cavity in two. A “vapour barrier” traps any migrating water vapour in the cavity on one side of the material. Generally, this would be on the warmer side of the material and an increasing level of water vapour present in this cavity will increase the temperature at which dew point occurs (i.e., making condensation more likely to occur). If the temperatures in the cavity drop low enough to cause the material’s temperature to drop to the dew point of the air on the warm side, then condensation will start to form on the surface of the material.

In theory, as the WVT of products employing the general inventive concept is greater, it allows the vapour to more readily transfer through such materials to the cavity on the cooler side where it will disperse by natural ventilation. This reduces the build-up of water vapour on the warm side, and in turn reduces the dew point temperature and the concordant risk of condensation occurring within the insulated cavity.

For comparative purposes, the general inventive concept of tapered perforations was tested against an otherwise equivalent material having substantially the same array of regular (i.e., non-tapered) perforations. The present invention has been set against the background of the Applicant’s own commercial product, Permicav®; as such, it seemed apt to test the general inventive concept by way of providing tapered perforations in the same material as that found in Permiwall®.

In the “tapered” product, as a general proposition, the perforations on the anti-glare foil (the “basal” end, as described above) are preferably around five times the diameter of those on the plain foil face (the “apical” end, as described above), making them around 25 times the overall opening area. This approximate ratio is thought to ensure that a product embodying the general inventive concept may give rise to advantageous water barrier and air barrier properties. Of course, the 5:1 ratio is not a critical requirement of the present invention; this ratio is exemplary, only. Using the “basal” end for the purposes of comparison, the perforations cover about 5% of the total surface area of the anti-glare facing.

For comparative purposes in respect of thermal performance parameters, Permicav® has been shown to exhibit total R-values for the building element as required by the Energy Provisions of the Building Code of Australia. Such products are

- 15 manufactured, tested and packaged in conformance with AS/NZS 4859.1. The contribution of the product total R-values depends on installation and environmental conditions, but in brick veneer walls (heat flow in Rt 1.7; heat flow out Rt 1.9), and in double brick walls (heat flow in Rt 1.8; heat flow out Rt 2.0), Permicav® has demonstrated excellent thermal performance characteristics. As mentioned elsewhere, the inventive “tapered” product delivers largely identical thermal performance (see, Table 1, below) despite having a greater surface area “cut out” of the anti-glare facing of the material (i.e., the relatively increased size of the exit openings).

Table 1: Comparative test data for the inventive material versus the closest prior art

Characteristic	Test method	Permiwall®	Invention
Flammability index	AS 1530.2	<5	<5
Material thermal resistance	ASTM C518	0.15m²-K/W	0.15m²-K/W
Emittance	ASTM E408	E0.03	Reflective: E0.03
Burst Force	AS 3706.4	1.0 kN	1.0 kN
Vapour barrier (“WVT”)	ASTM E96	Medium	Low
Shrinkage	AS/NSZ 4201.3	< 0.5%	< 0.5%
Dry delamination	AS/NSZ 4201.1	Pass	Pass
Wet delamination	AS/NSZ 4201.2	Pass	Pass
Water barrier	AS/NSZ 4201.4	High	High
Water absorbency	AS/NZS 4201.6	Unclassified	High
Corrosion resistance	AS/NZS 4859.1	Pass	Pass

Further, industry Standards against which Permicav® has been accredited or tested against include BS/I.S. EN ISO 9001:2008 (quality management); flammability (AS 1530.2; low; index < 5); thermal resistance (ASTM C518; R0.15; emittance (ASTM E408; reflective: E0.03; anti-glare: E0.05); vapour transmission (ASTM E96; medium); dry delamination (AS/NZS 4201.1; pass); wet delamination (AS/NZS 4201.2; pass); shrinkage (AS/NZS 4201.3; < 0.5%); water penetration (AS/NZS 4201.4; high resistance); water absorbency (AS/NZS 4201.6; unclassified); and burst force (AS 3706.4; 1.0 kN)

For comparative purposes, the commercial product Permiwall®, comprising substantially regular perforations between opposed surfaces, was tested against an otherwise identical product defined by the inventive tapered perforations (LDPE closed cell structure, perforations -2.5 mm apart, generally regularly spaced, basal opening about

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0.5 mm diameter, apical opening about 0.1 mm diameter, perforations generally regular).

The comparative test data were largely the same, aside from the results for water absorbency (Permiwall® was not tested in this regard) and vapour barrier (WVT), per ASTM E96. In respect of the comparative WVT data, the regularly-tapered Permiwall® 5 was categorised as “medium” resistance, whereas the otherwise identical material having the inventive tapered perforations achieved a “low” resistance rating.

Further testing was undertaken so as to provide some quantitative basis for the qualitative comparative test results expressed above in respect of WVT. In this respect, four materials were tested under laboratory conditions; the results are provided in Figure 10 10. The first material was a common construction brick; the second was a sample of

Permiwall® without any perforations (z.e., non-vapour permeable reflective insulation sheeting); the third was regularly-perforated Permiwall®; and the fourth was an otherwise identical material embodying the tapered perforations of the present invention. As measured, the inventive material (WVT -1.5 g/h.m²) gave up to five times better WVT 15 performance than regular Permiwall® (WVT -0.3 g/h.m²) despite exhibiting the same thermal properties. These data show conclusively that the tapered perforations according to the present invention achieve improved WVT relative to the closest prior art (z.e., Permiwall®). The data further show that use of the inventive material in relatively humid or high-condensation environments will provide for an equivalent energy profile relative to 20 Permiwall®, without the attendant and undesirable risk of increased condensation, mould, mildew, odour and rot.

According to the term “tapered”, the invention consists in any perforation having one opening larger than the other - with a continuous conduit therebetween. Exemplary ratios of the diameter of the opening on the anti-glare (basal) side to the diameter of the 25 opening on the plain foil (apical) side can be anywhere from approximately 1.1:1 through to 100:1 or thereabouts. Especially preferred ratios are about 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, 8:1, 8.5:1, 9:1, 9.5:1, and 10:1. Some more preferred ratios are 4.1:1, 4.2:1, 4.3:1, 4.4:1, 4.5:1, 4.6:1, 4.7:1, 4.8:1, 4.9:1, 5:1, 5.1:1, 5.2:1, 5.3:1, 5.4:1, 5.5:1, 5.6:1, 5.7:1, 5.8:1, 5.9:1, 6:1 and thereabouts. Further preferred 30 ratios are 3.2:1, 3.4:1, 3.6:1, 3.8:1; 6.2:1, 6.4:1, 6.6:1, and 6.8:1.

To clarify, it is intended by the Applicant to define within the bounds of the general inventive concept all ratios within the general limits of 1.1:1 to 100:1 or thereabouts. The general inventive concept of an improved WVT profile (z.e., less condensation) being

- 17provided for by a tapered perforation in an insulating material is well characterised within the exemplary limits quoted above.

The above passage relates to the ratio between basal opening diameter and apical opening diameter. By way of non-limiting example - and in describing a preferred embodiment of the invention, on the anti-glare side (basal), the diameter of the opening is approximately 0.5 mm; on the plain foil side, approximately 0.1 mm diameter. As mentioned elsewhere, the openings can be of any shape, but even when perforated with a round, or substantially round perforating pin, the resilient material will tend to relax into an irregularly-shaped opening.

It will be appreciated that the above 0.5 mm/0.1 mm openings are exemplary only and that any sized openings satisfying the general inventive concept of a tapered perforation may be applied here. For instance (basal/apical, round perforations, diameters, mm) 0.2/0.1; 0.3/0.1; 0.4/0.1; 0.5/0.1; 0.6/0.1; 0.7/0.1; 0.8/0.1; 0.9/0.1; 1.0/0.1; 0.3/0.2; 0.4/0.2; 0.5/0.2; 0.6/0.2; 0.7/0.2; 0.8/0.2; 0.9/0.2; 1.0/0.2; 1.1/0.2; 1.2/0.2; 1.3/0.2; 1.4/0.2;

1.5/0.2; 0.4/0.3; 0.5/0.3; 0.6/0.3; 0.7/0.3; 0.8/0.3; 0.9/0.3; 1.0/0.3; 1.1/0.3; 1.2/0.3; 1.3/0.3;

1.4/0.3; 1.5/0.3; 0.5:0.4; 0.6:0.4; 0.7:0.4; 0.8:0.4; 0.9:0.4; 1.0:0.4; 1.1:0.4; 1.2:0.4; 1.3:0.4;

1.4:0.4; 1.5:0.4; 1.6:0.4; 1.7:0.4; 1.8:0.4; 1.9:0.4 mm, etc.

To clarify, it is intended by the Applicant to define within the bounds of the general inventive concept all opening diameters within the general limits of 0.1 to 2 mm or thereabouts. The general inventive concept of an improved WVT profile (i.e., less condensation) being provided for by a tapered perforation in an insulating material is well characterised within the exemplary limits quoted above.

An insulating material embodying the inventive concept has a plurality of such perforations. These may be dispersed in an array that is regular/uniform or irregular whilst in keeping with the general inventive concept. In practice, it has been found that an appropriate balance between WVT and heat transfer characteristics is achieved in an insulating material wherein the plurality of perforations is spaced, substantially regularly, approximately 2.0 to 2.5 mm apart. However, it will be appreciated that any approximate spacing within these generally preferred distances are in keeping with the inventive concept. For instance, the generally regular spacings may be 0.5, 0.6, 0.7, 0.8, 0.9, 1.0,

1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1,

3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4 or 4.5 mm apart. In particularly preferred embodiments, the generally regular spacing is 2.0, 2.02, 2.04, 2.06, 2.08, 2.1,

- 182.12, 2.14, 2.16, 2.18, 2.2, 2.22, 2.24, 2.26, 2.28, 2.3, 2.32, 2.34, 2.36, 2.38, 2.4, 2.42, 2.44, 2.46, 2.48, 2.5, 2.52, 2.54, 2.56, 2.58 or 2.6 mm.

Clearly, an appropriate balance must be struck between attempting on the one hand to ensure that there are sufficient perforations to allow for optimal WVT in a given application, whilst on the other hand, it is not desirable to provide for too many perforations lest the heat transfer profile of the insulating material be compromised.

According to a potential commercial product embodying a first aspect of the invention there is provided insulation sheeting comprising a body having a pair of opposed surfaces, the body comprising a closed cell crosslinked low density polyethylene (LDPE) structure, the body being perforated for vapour permeability therethrough between the opposed surfaces, the perforations being tapered (2.5 mm apart, generally regularly spaced, basal opening about 0.5 mm diameter, apical opening about 0.1 mm diameter, perforations generally regular).

In other commercial embodiments, the perforations are of a size, spacing and number to provide permeability to water vapour in accordance with a “low” classification for resistance to water vapour transmission under Australian and New Zealand standards AS/NZS 4200.1 and/or AS/NZS 4859.1. For buildings insulated with the inventive tapered product, such permeability will allow the building “breathe” through the insulation sheeting and also minimise the build-up of condensation attributable to the barrier-effect of the insulation sheeting.

In preferred embodiments of the proposed commercial product, the cell structure may comprise a closed cell structure. In one embodiment, the closed cell structure may comprise a single layer cell structure. The single layer cell structure may comprise a plurality of plastic membranes bonded together to form a plurality of air cells therebetween. The plastic membranes used in the formation of the closed cell structure may typically comprise of low-density polyethylene (LDPE), high density polyethylene (HDPE), or linear low-density polyethylene (LLDPE). Preferably, the membrane thickness is about 175 pm or smaller. The single layer cell structure preferably comprises a plurality of cells of generally cylindrical construction each of a diameter between about 8 mm and 25 mm, and a depth of between about 3 mm and 10 mm. Preferably, the diameter of each cell is about 10 mm. Preferably, the thickness of the sheeting between the two opposed surfaces is about 4 mm, in which case the depth of each cell would be about 3 mm.

- 19In another envisaged commercial embodiment, the cell structure may comprise a closed cell foam structure. Preferably, the closed cell foam structure comprises polyethylene foam. More preferably, the closed cell foam structure comprises cross-linked low density polyethylene (LDPE) foam. The foam structure is advantageous as it provides resistance to moisture absorption and thereby enhances resistance to the development of mould. The LDPE foam is advantageous as it provides the insulation sheeting with enhanced thermal and acoustic insulation characteristics as well as greater resistance to heat and flame.

The cell structure may define at least one of the opposed surfaces of the body. However, it is preferred that the body further comprises two outer layers between which the cell structure is deposed, with the outer layers defining the respective opposed surfaces.

Preferably, at least one of the two outer layers comprises a foil. More preferably, both outer layers comprise a foil. Preferably, the foil comprises a reflective foil such as aluminium foil. The aluminium foil may comprise 99.5 percent pure aluminium reflective foil.

Preferably, one of the reflective layers may be treated for glare reduction. The layer may be treated in any appropriate way, such as by applying a surface treatment such as colouring to the exposed surface of the layer or by applying a film incorporating the colouring to the exposed surface of the layer. Any appropriate colouring can be used, and particularly suitable colours for the surface treatment comprise red, blue, green or orange tones.

The treatment for glare reduction is designed to provide a reduction of glare to provide greater comfort and protection against glare blindness while still providing a low enough emittance to provide thermal resistance by way of an upper reflective air space ideally within a range of E = 0.08 to E = 0.14.

Alternatively, the foil can be anti-glare foil. In a preferred embodiment, one face (the “basal” face) is anti-glare foil whereas the other face (the “apical” face) is regular aluminium foil. The selection of anti-glare and regular foils for the respective faces is based on thermal considerations; the anti-glare side faces the interior of the building.

The cell structure is preferably provided with fire retardancy. This may be achieved by the addition of an appropriate quantity of a fire retardant substance to the resin from which the cell structure is formed. The fire retardant may provide a fire index of less than or equal to 5 under the Australian Standard AS 1530.2.

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Preferably, at least one of the outer layers is reinforced for tear resistance. The reinforcement may be provided by a scrim bonded to the foil for reinforcement to provide strength and tear resistance. Preferably, the scrim comprises high density polyethylene weave laminated to the foil. Other types of scrim can also be used, one example being polypropylene weave. One or more scrim layers can be provided under each outer layer, as means of physical reinforcement.

Preferably, antioxidant is added to provide the cell structure with durability. Preferably, UV protection is also provided to the insulation sheeting.

Preferably, the perforations are formed after construction of the insulation sheeting.

In this way, the perforations extend not only through the two outer layers but also through the cell structure located therebetween. Further, the perforations in the outer layers and the cell structure are in alignment to assist air and moisture vapour transmission through the sheeting. The perforations may be generated by perforating the sheeting with a perforating device comprising a tool having a set of sharp end extrusions designed to perforate the sheeting at a variety of predetermined intervals.

Preferably, the perforating tool has a regular cross-section and is tapered along its length. By analogy, one may think of a pin-head, which tapers along a generally regularlycross sectioned shaft to a point. The desired dimensions of each tapered perforation is achieved by inserting the perforating tool (i.e., large-scale pin head) through the sheet 20 insulating material to a predetermined depth such that the appropriate dimensions of both basal (approx. 0.5 mm) and apical (approx. 0.1 mm) openings is achieved.

The perforations are preferably punched into pre-formed insulation sheeting by a machine. The machine foreseeably has a plurality of tapered perforating tools spaced in a regular or irregular array at predetermined spacings. The plurality of perforating tools can 25 be arranged for continuous perforating. In this respect, the perforator is essentially a roller with literally thousands of small pins that perforate the material as it passes under it. The roller can be calibrated to get the perforation depth precise so as not to over or under penetrate the material.

Alternatively, the perforating machine is arranged so as to provide for “batch” operation. In this respect, the array of tapered perforating tools is arranged on a plate, facing downward. The machine then punches, or “stamps” each section of the insulating material as it passes underneath. As with the above embodiment, the depth to which the perforating tool pierces the insulating material is paramount; the appropriate entry (basal)

-21 and exit (apical) opening sizes must be achieved.

As a further alternative, it may be possible to obtain the tapered insulating material via injection molding against a cast of perforating tools embedded in a mold and withdrawable thereform. However, either of the above two puncturing methods would appear more easily applied to industry as at the present date.

Preferred Embodiment of the Invention

Referring now to Figures 2 to 5 of the accompanying drawings, there is shown insulation sheeting according to a first embodiment, the sheeting comprising a body 10 having two outer layers 11,12 with a cell structure 13 bonded therebetween. Each outer layer 11,12 has an outer surface 14. The body 10 is of a thickness between the outer surfaces 14 which allows the insulation sheeting to be disposed in a rolled configuration and also unrolled to assume a substantially flat configuration, such as that in which the insulating material will sit, in use. In this embodiment, the insulation sheeting has a thickness of between about 4 to 6 mm between the outer surfaces 14 (see, Figure 3).

The first outer layer 11 comprises reinforced reflective aluminium foil. More particularly, the first outer layer 11 comprises 99.5% pure aluminium reflective foil reinforced with high density polyethylene scrim. The reinforcement enhances the tensile strength of the insulation sheeting 10, allowing it to be installed over large spans in a building construction. The reinforcement also provides a greater tear strength and burst strength.

The second outer layer 12 preferably comprises anti-glare foil, and it is optionally reinforced with a scrim as described above. According to a preferred embodiment, the tapered perforation is disposed such that the apical (small) opening is on the aluminium foil face 11 and the basal (larger) opening is on the anti-glare face 12. However, it will be appreciated that this is merely a preferred embodiment of the invention; both faces can be the same foil - or not comprise a foil outer layer at all.

In this embodiment, the cell structure 13 is a “closed” cell structure comprising first and second polyethylene membranes 15 and 17, respectively, bonded together. With this arrangement, the closed cell structure 17 comprises a single-layer cell structure. The first membrane 15, which is best seen in Figure 5, is formed by a vacuum suction process into a series of depressions 19 having open ends 20 which are closed by the second membrane 17. With the closure of the openings 20 in the first membrane 15 by the second membrane

-2217, the depressions 19 form air cells 21 within the cell structure.

In this embodiment, the first and second membranes 15,17 comprise fire retarded modified low-density polyethylene (LDPE), high density polyethylene (HDPE) or linear low-density polyethylene (LLDPE).

Each air cell 21 in this embodiment is preferably of generally circular cross-section, having a diameter “a” and a depth “b”, as illustrated in Figure 5. In this way, each cell 21 is of generally cylindrical construction (see, feature 13 of Figure 6). In this embodiment, the diameter “a” is about 10 mm; the depth “b” is about 3 mm, based on the overall thickness of the sheeting 10 being about 4 to 6 mm, preferably 5 mm.

The exposed surface of the first layer 11 is optionally treated to provide some glare reduction while retaining heat reflective characteristics. Glare reduction can be particularly desirable on construction sites where the sheeting may be exposed for some time so creating a glare problem for workers in the vicinity. In one embodiment, the treatment comprises colouring. Suitable colours for the exposed surface may comprise red, blue, green, or orange tones.

The body 10 is punctured with tapered perforations to provide the insulation sheeting with permeability to water vapour (by way of an improved WVT profile, as described above). In this regard, the body 10 has a plurality of tapered perforations 25 extending between the two outer surfaces 14 thereof (see, Figures 3 and 4). The tapered perforations 25 comprise openings 27 which open onto the outer surfaces 14 at openings

28. As explained extensively above, the general inventive concept is that a “tapered” perforation has one opening of smaller size than the other - and a substantially continuous conduit therebetween for the flow of water vapour. The openings 27 of course also open onto the interior of the air cells 21 within the cell structure 13 from opposed sides thereof. In this embodiment, the perforations 25 are formed by piercing the body 10 with a perforating tool, which is provided either on a roller or as a stamping tool, again as described above.

The perforations 25 are of a size, spacing and number to provide the insulating sheeting with selective permeability to water vapour by way of an improved WVT profile relative to a non-tapered perforation of comparable dimensions. This allows a building in which the sheeting is installed to “breathe” through the sheeting and to minimise any condensation arising within the building envelope cavity from the barrier-effect of the sheeting. More particularly, the tapered perforations 25 are such that the insulation

-23 sheeting can comply with the permeability rating required for wall and floor applications. The perforations 25 are, of course, of a size which excludes normal passage of water in liquid form therethrough, yet optimises WVT therethrough whilst at once minimising the reduction in the heat transfer profile that occurs upon placing openings in an otherwise sheet-like insulating material. In accordance with the invention, the perforations are tapered with the approximate diameter ratio of basal opening (anti-glare face) to apical opening (foil face) being about 5:1; the approximate diameter of the basal opening is 0.5 mm and the approximate diameter of the apical opening is 0.1 mm; the surface area ratio of basal opening to apical opening is thereby about 25:1.

While the perforations 25 provide the body 10 with the requisite permeability to air and water vapour, ideally they do not adversely affect to any significant extent the thermal barrier characteristics of the insulation sheeting relative to the equivalent material perforated with a non-tapered conduit.

In Figure 6, it can be clearly seen that the openings 27 on the top face 11 are smaller than their corresponding openings 27 on the bottom face 12. Figure 6 depicts insulation sheeting according to a second embodiment, which is similar to that of the first embodiment, with the exception that the second layer 12 is formed of polyethylene sheeting rather than reflective aluminium foil. As with the first embodiment, the body 10 has tapered perforations 25 to provide the requisite permeability to water vapour. The openings 27 on the top face 11 are perceptibly smaller than their corresponding opening 27 on the bottom face 12; this accords with the “tapered perforation” requirement of the general inventive concept, as described above.

Referring to Figure 7 and Figure 8, there is shown insulation sheeting according to a third embodiment. At the time of filing, it is envisaged that this third embodiment is most likely to correspond with the commercial form of the invention. The insulation sheeting according to the third embodiment is similar in some respects to the insulation sheeting according to the first embodiment and accordingly, corresponding reference numerals are used to identify the corresponding parts (e.g., the openings 27). The body 10 is of a thickness between the outer surfaces 14 (see, Figure 8) which allows the sheeting to be disposed in a rolled configuration and also unrolled to assume a substantially flat configuration. In this particular embodiment, the thickness is between about 4 and 6 mm, more preferably about 5 mm.

The cell structure 13 comprises a closed cell foam structure. The closed cell foam

-24structure 13 comprises flexible light gauge foam which in this embodiment is cross-linked LDPE foam. The polyethylene foam preferably incorporates UV protection, fire retardancy and an anti-oxidant. The fire retardancy is such as to provide compliance with the Australian Standard AS1530.2. Indeed, the fire retardant may provide a Fire Index of less than or equal to 5 under the Australian Standard AS 1530.2. Anti-oxidant protection is such as to afford a minimum 15 year product lifecycle when installed.

The cross-linked structure of the closed cell foam structure 13 provides advantageous thermal and acoustic insulation characteristics, as well as resistance to heat and flame. Specifically the closed cell foam structure 13 produced from cross-linked LDPE foam allows construction of insulation sheeting which can be generally thinner than that of the first embodiment because of the inherent stiffness in the foam arising from the cross-linking.

Further, the closed cells within the cross-linked LDPE foam are much smaller in size than the air cells in the earlier embodiments (see, Figure 3, feature 21, cf. Figure 7, feature 13). Indeed, the closed cells in the foam structure 13 comprise micro-encapsulated air cells, typically of a cross-sectional size less than 0.1 mm or thereabouts. With this arrangement, the air cells are relatively evenly distributed within the foam cell structure 13, so affording appreciable fire resistance; this is because there are no relatively large bubbles of air to support combustion. The relatively even distribution of micro-encapsulated air cells also provides resistance to thermal and acoustic energy transfer.

The tapered perforations 25 comprise openings 27 formed by piercing the body 10 with a perforating tool as described above (i.e., either continuously rolled, or stamped batch-wise). The openings 27 not only extend through the outer layers 11, 12 to open on to the outer surfaces 14 thereof at openings 28 but also extend through the closed cell foam structure 13. The tapered perforations 21 may not always be readily apparent to the naked eye in the closed cell foam structure 13 owing to the collapsible/resilient nature of the foam and the small dimensions involved. Even though collapsed within the closed cell foam structure 13, the tapered perforations 25 do provide a transmission path through the body 10 for, importantly, water vapour.

In use, the inventive insulating material is applicable to interstitial cavities in, for instance, residential and commercial buildings. In preferred application, the inventive material can be installed within double brick wall cavities or brick veneer wall cavities. The person skilled in the art will readily appreciate the terminology used herein.

-25 As an example, when the inventive product is to be installed within a double brick wall cavity, the best method of installing the material could be defined as: 1) lay outer leaf of brickwork with wall ties in place; 2) clip a spacer biscuit onto every second wall tie, or as required to maintain a nominal 20 mm air space between the brick face and inventive material, and push against the brickwork; 3) roll out the inventive material horizontally (with the anti-glare surface (larger openings) facing the installer) and offer up to the wall; 4) cut a slit for each wall tie to penetrate the inventive material; 5) push the inventive material over the wall ties until it is against the spacer biscuit; 6) allow an approximate 50 mm overlap at joins with the upper layer overlapping on the outside of the lower, and tape with a 48 mm wide reinforced foil tape; and 7) lay the inner leaf of brickwork so as to define the interstitial cavity in which the inventive material resides.

As described, the anti-glare surface is disposed toward the interior of the building being insulated. As such, the water vapour effectively flows from the larger (“apical”) opening through the body of the insulating material, and out of the smaller (“basal”) opening.

It will be appreciated that the kit of parts as defined according to the ninth aspect of the present invention provides all of the components necessary to effectively install the inventive material via a do-it-yourself (DIY) scenario.

From the foregoing, it is evident that the embodiments each provide insulation sheeting which is relatively simple in construction and highly effective in use, yet permeable to air and advantageously selectively permeable to water vapour so as to be particularly suitable for wall and floor applications.

Although the invention has been described with reference to specific examples it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A method of providing for water vapour transfer through an insulation material, said method comprising providing one or more continuous perforation/s through said insulating material, said perforation/s being tapered such that for each said perforation an entry opening is of substantially different size (area) to its corresponding exit opening.
2. A method according to claim 1, the method comprising providing a plurality of said continuous perforations in an insulating sheet material.
3. A method according to claim 2, wherein said entry opening and its corresponding exit opening are, on average throughout the plurality of perforations, in an approximate size (area) ratio of between about 100:1 to about 1.1:1.
4. A method according to claim 3, wherein said ratio is between about 20:1 and about 2:1.
5. A method according to claim 4, wherein said ratio is between about 10:1 and about 3:1.
6. A method according to claim 5, wherein said ratio is between about 7:1 and about 4:1.
7. A method according to claim 6, wherein said ratio is between about 6:1 and about 4.5:1.
8. A method according to claim 7, wherein said ratio is about 5:1.
9. A method according to any one of the preceding claims, wherein said entry opening has on average throughout the one or more perforations, a span of between about 0.1 mm and about 5.0 mm.
10. A method according to claim 9, wherein said entry opening has a span of between about 0.2 mm and about 3.0 mm.
11. A method according to claim 10, wherein said entry opening has a span of between about 0.3 mm and about 1.5 mm.
12. A method according to claim 11, wherein said entry opening has a span of between about 0.35 mm and about 1.0 mm.
13. A method according to claim 12, wherein said entry opening has a span of between about 0.4 mm and about 0.8 mm.
14. A method according to claim 13, wherein said entry opening has a span of between about 0.45 mm and about 0.6 mm.
15. A method according to claim 14, wherein said entry opening has a span of about 0.5 mm.
16. A method according to any one of the preceding claims, wherein said one or more continuous perforations is provided in said insulating material either substantially continuously via a roller-type process; or batch-wise via a stamp-like process.
17. A method according to claim 16, wherein said roller-type process and/or said stamp-like process are calibrated to ensure that each perforation is made through said insulating material to a predetermined depth, thereby to provide for exit and entry openings of predetermined sizes (areas) within the insulating material.
18. A method according to claim 17, wherein the predetermined size of said entry opening is about 0.5 mm and the predetermined size of said exit opening is about 0.1 mm.
19. A method according to claim 17 or claim 18, wherein said roller-type process comprises a plurality of tapered perforating pins arranged in an array at

-28predetermined intervals about the circumference of said roller, each said pin disposed substantially radially outwards, wherein in order to effect said substantially continuous method, said insulating material is brought into perforating engagement with said perforating pins such that when said insulating material is moved with respect to said roller (or vice versa), said roller rotates to thereby perforate successive areas of said insulating material in a substantially continuous manner.
20. A method according to claim 17 or claim 18, wherein said stamp-like process comprises a plurality of tapered perforating pins arranged in an array at predetermined intervals over a face of a stamping plate, each said pin disposed substantially outwards from the surface of said plate, wherein in order to effect said batch-wise method, said insulating material is brought into perforating engagement with said plate (or vice versa), thereby to effect one stamping batch; and wherein following said stamping batch, said plate is removed from said perforating engagement, and optionally a further area of insulating material is brought into perforating engagement with said plate, to thereby perforate successive areas of said insulating material in a batch-wise manner.
21. An insulation material comprising a body having a pair of opposed faces, the body comprising a cell structure, the material further comprising one or more tapered perforations extending between and through said opposed faces to define an entry opening of larger size (area) than its respective exit opening.
22. An insulating material according to claim 21, comprising a plurality of said tapered perforations.
23. An insulation material according to claim 21 or claim 22, wherein the cell structure comprises a closed cell structure.
24. An insulation material according to claim 23, wherein the cell structure comprises a single layer cell structure.
25. An insulation material according to claim 24, wherein the single layer cell structure comprises a plurality of plastic membranes bonded together to form a plurality of air cells therebetween.
26. An insulation material according to claim 23, wherein the closed cell structure comprises a closed cell foam structure.
27. An insulation material according to claim 26, wherein the closed cell foam structure comprises polyethylene foam, polypropylene foam or any other applicable foam or combination thereof.
28. An insulation material according to claim 26 or claim 27, wherein the closed cell foam structure comprises cross-linked low density polyethylene (LDPE) foam.
29. An insulation material according to any one of claims 21 to 28, wherein the body further comprises an outer layer adjacent the cell structure, the outer layer defining one of the opposed surfaces.
30. An insulation material according to any one of claims 21 to 28, wherein the body further comprises two outer layers between which the cell structure is disposed, the outer layers defining the respective opposed surfaces.
31. An insulation material according to claim 29 or claim 30, wherein at least one of the outer layers comprises a foil.
32. An insulation material according to any one of claims 21 to 28, wherein the cell structure defines at least one of the opposed surfaces of the body.
33. An insulation material according to any one of claims 21 to 32, wherein the tapered perforations are formed after construction of the insulation material.
34. An insulation material according to claim 33, wherein the tapered perforations are generated by perforating the material in a substantially continuous or batch-wise

-30manner by an apparatus adapted for imparting said tapered perforations within said insulation material.
35. An insulation material according to any one of claims 21 to 34, wherein said entry opening and its corresponding exit opening are, on average throughout the one or more perforation/s, in an approximate size (area) ratio of between about 100:1 to about 1.1:1.
36. An insulation material according to claim 35, wherein said ratio is between about 20:1 and about 2:1.
37. An insulation material according to claim 36, wherein said ratio is between about 10:1 and about 3:1.
38. An insulation material according to claim 37, wherein said ratio is between about 7:1 and about 4:1.
39. An insulation material according to claim 38, wherein said ratio is between about 6:1 and about 4.5:1.
40. An insulation material according to claim 39, wherein, wherein said ratio is about 5:1.
41. An insulation material according to any one of claims 21 to 40, wherein said entry opening has on average throughout the one or more perforation/s, a span of between about 0.1 mm and about 5.0 mm.
42. An insulation material according to claim 41, wherein said entry opening has a span of between about 0.2 mm and about 3.0 mm.
43. An insulation material according to claim 42, wherein said entry opening has a span of between about 0.3 mm and about 1.5 mm.
44. An insulation material according to claim 43, wherein said entry opening has a span of between about 0.35 mm and about 1.0 mm.
45. An insulation material according to claim 44, wherein said entry opening has a span of between about 0.4 mm and about 0.8 mm.
46. An insulation material according to claim 45, wherein said entry opening has a span of between about 0.45 mm and about 0.6 mm.
47. An insulation material according to claim 46, wherein said entry opening has a span of about 0.5 mm.
48. An insulating material according to any one of claims 21 to 47, wherein said one or more perforation/s are spaced apart in a generally regular arrangement.
49. An insulating material according to claim 48, wherein said one or more perforation/s are spaced apart by about 0.5 mm to about 5.0 mm.
50. An insulating material according to claim 49, wherein said one or more perforation/s are spaced apart by about 1.0 mm to about 4.0 mm.
51. An insulating material according to claim 50, wherein said one or more perforation/s are spaced apart by about 1.5 mm to about 3.0 mm.
52. An insulating material according to claim 51, wherein said one or more perforation/s are spaced apart by about 2.0 mm to about 2.5 mm.
53. An insulation material according to any one of claims 21 to 52, wherein said material is between about 3 mm and about 7 mm in thickness.
54. An insulation material according to claim 53, wherein said material is between about 4 mm and about 6 mm in thickness.
55. An insulation material according to claim 54, wherein said material is about 5 mm in thickness.
56. An insulation material according to any one of claims 19 to 21, wherein said body is foam such as cross-linked LDPE foam; said opposed faces are comprised of aluminium foil (reflective or anti-glare); and wherein the ratio of said entry to said exit openings is approximately 5:1; wherein the span of said entry opening is about 0.5 mm; wherein said plurality of perforations are spaced generally regularly at intervals of about 2.5 mm; wherein said insulating material is about 5 mm in thickness; and wherein said entry and exit openings are generally circular.
57. An insulating material according to any one of claims 31 to 56, wherein one of the outer layers has a reflective finish; and wherein the other outer layer has an antiglare finish.
58. An insulating material according to claim 57, wherein said entry openings are made in said anti-glare outer layer; and wherein said exit openings made in said reflective outer layer.
59. An insulating material according to claim 58, wherein when installed in use within a building cavity, the anti-glare outer layer comprising the plurality of entry openings is disposed toward the exterior of the building; and the reflective outer layer comprising the plurality of plurality of entry openings is disposed toward the interior of the building.
60. In a sheet-like insulating material having a plurality of perforations extending therethrough, an improvement consisting in tapered perforations so as to provide for a relatively improved water vapour transfer (WVT) profile relative to an otherwise identical material having a corresponding plurality of non-tapered perforations.
61. A method of perforating a sheet of insulating material with a plurality of tapered perforations via a substantially continuous process, said method comprising the

-33steps of providing a roller-type arrangement calibrated to ensure that each perforation is made through said insulating material to a predetermined depth, thereby to provide for exit and entry openings of predetermined sizes within the insulating material, wherein said roller-type arrangement comprises a plurality of tapered perforating pins arranged at predetermined intervals around the circumference of said roller, each said pin disposed substantially radially outwards, wherein in order to effect said substantially continuous method, said insulating material is brought into perforating engagement with said roller such that when said insulating material is moved with respect to said roller (or vice versa), said roller turns to thereby perforate successive areas of said insulating material.
62. An insulating material perforated with a plurality of tapered perforations, by a substantially continuous method as defined according to claim 61.
63. A method of perforating a sheet of insulating material with a plurality of tapered perforations via a batch-like process, said method comprising the steps of providing a stamper calibrated to ensure that each perforation is made through said insulating material to a predetermined depth, thereby to provide for exit and entry openings of predetermined sizes within the insulating material, wherein the stamper comprises a plurality of tapered perforating pins arranged at predetermined intervals over a face of a stamping plate, each said pin disposed substantially outwards from the surface of said plate, wherein in order to effect said batch-wise method, said insulating material is brought into perforating engagement with said plate, thereby to effect one stamping batch; and wherein following said one stamping batch, said plate is removed from said perforating engagement, and optionally a further area of nonperforated insulating material is brought into perforating engagement with said plate, thereby to effect said batch-wise perforating.
64. An insulating material perforated with a plurality of tapered perforations, when soperforated by a batch-wise method as defined according to claim 63.
65. A method for providing relatively optimised water vapour transfer (WVT) through a sheeted insulating material disposed within interstitial cavities of a building, said

-34method comprising the step of providing said insulating material with a plurality of tapered perforations extending between the respective opposed surfaces of said sheeted insulating material such that said water vapour is selectively permeable through said perforations, thereby to prevent condensation within said cavities.
66. A kit for on-the-shelf sale, the kit comprising an insulating material as defined according to any one of claims 21 to 59; and at least one ancillary article selected from: at least one spacer biscuit; at least one wall tie; at least one roll of reinforced foil ducting tape for binding adjacent sheets in use; at least one knife; and instructions.
67. A method according to claim 1; an insulating material according to claim 21; in a sheet-like insulating material an improvement according to claim 60; a method according to claim 61; a method according to claim 63; an insulating material according to claim 64; a method according to claim 65; or a kit according to claim 66, substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples.