AU714688B2

AU714688B2 - Reflective laminate insulation product

Info

Publication number: AU714688B2
Application number: AU50748/96A
Authority: AU
Inventors: Ross Whitfield
Original assignee: Amatek Ltd
Current assignee: Fletcher Insulation Pty Ltd
Priority date: 1995-04-21
Filing date: 1996-04-19
Publication date: 2000-01-06
Anticipated expiration: 2016-04-19
Also published as: AU5074896A

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT oo Invention Title: REFLECTIVE LAMINATE INSULATION PRODUCT e e The following statement is a full description of this invention, including the best method of performing it known to me: 1 i ii DocumentlI REFLECTIVE LAMINATE INSULATION PRODUCT The present invention relates generally to insulation and in particular it relates to a reflective insulation laminate that is pliable and strong yet light weight. The invention has particular application in the building industry and is described in this context.

However, it should be appreciated that the invention has broader application and is not limited to this particular use.

It has long been recognised that it is important to incorporate adequate insulation into a building to reduce heating and cooling costs and to improve occupancy comfort.

The basic mechanisms of heat transmission in a building are radiation, conduction and convection. Radiation is often the most important mechanism for heat transfer. For S example it has been found that for a vertical uninsulated air space bounded by normal building materials such as masonry, wood and gypsum board, the approximate portions of the modes of heat transfer are: radiation :convection conduvection conduction In the case of heat flow through ceilings, the situation is similar, as under summer conditions 87% or more of the downward heat flow is by radiation. (Hassall, DNH. Reflective insulation and the control of thermal environments 1977).

Reflective insulation seeks to reduce heat transmission via radiation by S: producing a low emittance high reflectance barrier to attenuate radiation.

.oo..i S"Reflective insulation has been available for many years in a thin pliable membrane form made from aluminium foil laminated to paper with glass fibre reinforcement.

This product is supplied in rolls and is typically used for roof sarking or wall insulation where it may be wrapped around the outside of the frame of a building and affixed to the frame.

The product should be of adequate strength to resist tearing during the transport, handling and installation of the product.

A problem with known pliable reflective insulation sheets is that they are quite heavy. Typically the weight of such products can be in the range of 170 to 500 grams per square metre. Accordingly the overall weight of these products as supplied in rolls MC C:\WINWORD\MARLO\NODELETECDS\PN2574.DOC is quite high adding to transportation costs and making installation difficult. When the rolled product is installed in a wall or roof of a building, the roll of insulation material must be supported as the unfurled product is affixed to the wall or roof.

Accordingly, an object of the present invention is to provide a reflective insulation laminate product that is strong and yet light weight and is therefore easy to transport, handle and install.

The applicants have discovered that at least two different polymeric films having very different strength characteristics can be combined to produce a reflective insulation laminate sheet that overcomes the problems of the prior art. The overall strength characteristics of the laminate sheet make it suitable for use as a reflective insulation product yet the laminate sheet is still light weight.

Accordingly, in one embodiment the present invention provides a reflective insulation laminate sheet including; one or more layers of a first polymeric material having a high bursting force value and a high tensile modulus value; and one or more layers of a second polymeric material having a high propagation tear resistance value, wherein at least one face of the laminated sheet has an infrared emittance not greater than 0.08 and the overall weight of the laminated sheet does not exceed 180 grams per square metre.

Throughout the description and claims of this specification the following definitions apply. A "bursting force value" of a material is that value as measured by S Australian Standard 2001.2.19. A "tensile modulus value" of a material is that value as measured as 1% secant modulus by American Standard Test Method D882 in both the machine and transverse directions of the material. A "propagation tear resistance value" of a material is that value as measured by American Standard Test Method 1922 in both the machine and transverse directions of the material. A "edge tear resistance" value of material is that value is measured by Australian Standard 4200.1 in both the machine and transverse directions of the material.

The polymeric material that makes up the first layer or group of layers has a high bursting force value. This value is equal to or greater than 100 Newtons and more preferably equal to or greater than 200 Newtons. The material also has a high tensile modulus value which is equal to or greater than 15 kilonewtons per metre and more MC C:\WINWORD\MARLO\NODELETECDS\PN2574.DOC preferably 25 kilonewtons per metre in both the machine and transverse directions of the polymeric material.

The polymeric material that makes up the second layer or group of layers has a high propagation rear resistance value. This value is greater than or equal to 0.25 Newtons and more preferably greater than or equal to 0.50 Newtons in both the machine and transverse directions.

Layers, sheets or films of polymeric material are said to have a "machine direction". This is the direction along the sheet that it continuous with the direction in which the sheet exists from the manufacturing machine. When the sheets are formed *00 "*'0010 into rolls, the machine direction is usually the direction along the length of the roll.

:o Transverse direction is perpendicular to the machine direction and is alternatively referred to as cross direction.

OG The polymeric material having a high bursting force value and a high tensile 0000 modulus value that makes up the first layer or group of layers is preferably selected 00000 15 from the group of polymeric materials consisting of oriented polyester film, oriented polypropylene film, oriented nylon film, cast polypropylene film and cast polyvinylchloride film.

6:6 The most preferred oriented polyester film is made from polyethylene terephthalate

(PET).

The polymeric material having a high propagation tear resistance value that makes up the second layer or groups of layers is preferably selected from the group of polymeric O 6 8090.: materials consisting of blown or cast polyethylene film, blown or cast O 0 O polyethylene/polypropylene copolymer film, ethylene vinylacetate film, copolymer nylon film, ionomer film, acid copolymer film and plasticised polyvinylchloride film.

In a preferred embodiment the second layer or group of layers is made from blown polyethylene film.

the first layer or group of layers preferably has a total weight of between 9 and grams per square metre and most preferably between 15 to 25 grams per square metre. The second layer or group of layers preferably has a total weight of between 20 and 120 grams per square metre and most preferably between 25 to 50 grams per square metre.

It is preferable that the insulation sheet of this invention has a total weight of between 40 and 150 grams per square metre, more preferably not greater than 100 grams per square metre and most preferably about 80 grams per square metre.

The applicants have found that the preferred laminated sheet of the present invention has a bursting force value greater than 200 Newtons, and an edge tear resistance value of more than 45 Newtons.

Preferably the insulation sheet consists of one layer of polymeric material selected from each of the two groups of polymeric materials noted above. However, the applicant has found that the number of layers is not critical to the performance of 00"..010 the invention. Accordingly the reflective sheet could include a number of layers 0: selected from each of the groups of polymeric materials. For example, the insulation sheet may include one layer or polymeric material selected from the first group (ie.

S oriented polyester, oriented polypropylene etc.), a second layer selected from the 00@0 second group (ie. polyethylene etc.) and a further or third layer also selected from the first group wherein the final weight of the laminated sheet is below 180 grams per square metre. In other words, the insulation sheet of this invention could be made of multiple layers selected from each of the groups of specified polymers, so long as the final weight of the layers is below the value specified above. Furthermore, where the 0 insulation sheet includes such multiple layers, the applicants have found that the ordering of the layers is not critical to the performance of the invention.

As previously noted at least one face of the laminate product of this invention

S

has an infrared emittance of not greater than 0.08. Emittance is defined as the ratio of

S

the thermal radiation from a unit area of a surface to the radiation from a unit area of a full emitter (black body) at the same temperature. Accordingly, the surface of the laminate sheet of this invention having an infrared emittance of not greater than 0.08 not more than 8 percent of the amount of infrared radiation that a black body would emit at this same temperature. by having an emittance value of this magnitude, the laminate sheet of this invention is able to function effectively as a thermal insulator.

Preferably, at least one face of the laminate sheet has an emittance of not greater than 0.05.

In a preferred embodiment, the reflective insulation sheet of this invention includes a further layer that confers the specified infrared emittance property on the s ,A insulation sheet. This further layer maybe a metal foil laminated to the aforementioned

CO

a. 748-96a.doc:10/29/99 laminated structure with adhesive. A preferred metal foil is aluminium as it has an emittance of 0.05 or less. Furthermore aluminium foil is light weight; about 17 grams per square metre for foil having a thickness of 6.3 microns. Accordingly, aluminium foil can be incorporated into the insulation sheet of this invention without greatly increasing its overall weight.

Alternatively, the further layer may be a metallised deposit. Preferably the metal is aluminium and it can be deposited onto the laminate by known techniques such as vacuum metallising. Furthermore, the weight of an aluminium deposit layer is very light; less than 1 gram per square metre and adhesive is not required to fix the deposit to the other lays of the insulation sheet.

It is preferable that the further metal foil layer or metallised deposit be made from S a metal that is resistant to atmospheric corrosion. Aluminium is such a metal and this is a further advantage of using an aluminium foil layer or an aluminium deposit layer.

In a further preferred embodiment, both faces of the laminate may have an infrared emittance of not greater than 0.08, preferably not greater than 0.05. This may be achieved by laminating aluminium foil to both faces of the insulation sheet. Such .o double sided reflective insulation can be more effective than insulation sheets having a single reflective side.

Alternatively, only one face of the insulation sheet may have a low infrared 0oeS emittance value and the other face may have anti-glare properties. The provision of anti-glare helps reduce the discomfort experienced when installing the reflective insulation sheets.

S"Anti-glare properties can be conferred on one face of the insulation sheet by incorporating a colorant and matting agent into the polymeric material that forms the layer at this face of the sheet. For example in a preferred embodiment, this layer of the sheet is formed from blown polyethylene film and a colorant and matting agent is incorporated into this material.

As the insulation sheet of this invention is expected to have a long performance life, it is desirable to render the sheet resistant to oxidisation and other chemical degradation. Where one face of the sheet is a metal foil or a metallised deposit and the other side of the sheet is a polymer layer, the resistance to oxidisation of this layer can be enhanced by incorporating an anti-oxidant into the polymer material that makes up this layer. For example, where this outer layer is formed from blown polyethylene film, MC C:\WINWORD\MARLO\NODELETECDS\PN2574.DOC

L

500 ppm of Irganox 1010 can be incorporated into this polymer material. Irganox 1010 is an anti-oxidant manufactured by Ciba-Geigy.

It may be desirable to increase the tear resistance of the insulation sheet of this invention. This can be achieved by incorporating in the laminate a reinforcing fabric layer. Preferably this fabric is an open weave material such as scrim or mesh which can be trap laminated between two adjacent layers. Suitable fabric materials include glass filaments, nylon, polyester or other plastic material.

The layers of material that make up the insulation sheet of this invention can be laminated together by known techniques. For example, the layers can be laminated together using a hot melt adhesive or dry laminating adhesive which are well known in the laminating industry. A preferred dry laminating adhesive for use in this invention is an amine with an epoxide cross linker. As the insulation sheet of this invention is expected to have a long performance life, it is advantageous to use such an adhesive having a high content of epoxide cross linker so that the adhesive forms a very secure bond between adjacent layers of the laminate sheet. A suitable adhesive for use in this invention is Aquabond 444 manufactured by Morton. Alternatively, the polymeric layers can be thermally laminated together, thereby avoiding the use of adhesive.

S:In the manufacture of the insulation sheet of the present invention it is preferable to arrange the polymer layers so that as they enter the laminating machine, the machine directions of these polymer layers are aligned and extend substantially parallel to the machine direction of the laminated sheet itself. By "substantially parallel" we mean extending in substantially the same direction. Consequently, this produces a laminated sheet wherein the machine directions of the polymeric layers of the sheet extend in substantially the same direction and also extend in substantially the same direction as the machine direction of the laminated sheet itself. For other known reflective insulation laminate sheets, adjacent layers of polymeric material enter the laminating machine at 450 to the machine direction of the laminated sheet. This produces a laminated sheet wherein the machine directions of the polymeric layers of the sheet are arranged at 900 to each other and at 45' to the machine direction of the laminated sheet. This constructional feature is relied upon to impart strength to the laminated sheet. If the machine directions of the polymeric layers of such laminate sheets were aligned and extended in the same direction as the machine direction of the laminate sheet, the final product would have insufficient strength to adequately perform MC C:\WINWORDOWARLO\NODELETE\CDSPN2574.DOC as an insulation sheet. In contrast, the present invention relies upon the properties of the specified polymeric layers, not any specific method of construction. The method of manufacturing the laminated product of this invention as outlined above is far less costly and less complicated than laminating polymeric sheets together so that their machine directions are at an angle to each other.

Accordingly, in a preferred embodiment of this invention the one or more layers of first polymeric material and the one or more layers of second polymeric material are laminated together so that the machine directions of these layers extend substantially in the same direction and in the same direction as the laminated sheet itself.

Accordingly, the present invention also provides a method of manufacturing a reflective insulation laminate sheet including taking: one or more layers of a first polymeric material having a high bursting force value and a high tensile modulus value; and one or more layers of a second polymeric material having a high propagation tear resistance value, and conveying said layers of first and second polymeric materials into a laminating machine and laminating said layers together to form a laminated reflective insulation sheet, wherein said layers of polymeric materials are conveyed into said machine in substantially the same direction that the laminated sheet exits the machine 20-0£ so that the machine directions of the layers of polymeric material in the laminated sheet extend in substantially the same direction and in substantially the same direction as the machine direction of the laminate sheet itself, said laminate also having at least one face having infrared emittance not greater than 0.08 and the overall weight of said laminated sheet not exceeding 180 grams per square metre.

As noted earlier, the reflective insulation sheet of this invention can include a further layer that confers the specified infrared emittance property on the insulation sheet and this further layer can be an aluminium foil layer or aluminium deposit. In the manufacture of the laminated sheet, the aluminium foil layer or aluminium deposit can be adhered to one of the layers of polymeric material before that layer is adhered to the other layer or layers of polymeric material that make up the laminated sheet.

Alternatively, the layers of first and second polymeric material can be adhered to each other first and then the aluminium foil or deposit can be adhered to this combination of layers.

MC C:\WINWORD\MARLO\NODELETE\CDS\PN2574.DOC Preferred embodiments of the invention are hereinafter described with reference to the accompanying drawings in which:- Figure 1 is one embodiment of the reflective insulation sheet of this invention including an aluminium foil sheet.

Figure 2 is a second embodiment of the reflective sheet insulation sheet of this invention including an aluminium vacuum deposit layer.

Figure 3 is a further embodiment of the reflective insulation sheet of this invention including reinforcing mesh.

Figure 1 shoes a laminate product of this invention including an aluminium foil layer adhesive layers an oriented polyester or polypropylene layer and a polyethylene layer The overall weight of this laminate product is as follows: aluminium foil layer 17 grams per square metre; :i adhesive layer 3 grams per square metre; °""oriented polyester or polypropylene layer 17 grams per square metre; "adhesive layer- 3 grams per square metre;

S

polyethylene layer 40 grams per square metre; TOTAL 80 grams per square metre.

The laminate product illustrated in Figure 1 was tested and was found to have a bursting force value as measured by AS2001.2.19 of 230 newtons. The product was also found to have an edge tear resistance value as measured by AS4200.1 of 130 newtons in both the machine and lateral directions of the laminate product.

Figure 2 illustrates an alternative embodiment wherein an aluminium vacuum deposit is used instead of a foil layer. It includes aluminium deposit layer oriented polyester or polypropylene layer adhesive layer and a polyethylene layer As an aluminium vacuum deposit is used instead of a foil layer, an extra layer of adhesive is not required. The overall construction and weight of this laminate is as follows: aluminium deposit layer 1 gram per square metre; oriented polyester or polypropylene layer 17 grams per square metre; adhesive layer 3 grams per square metre; polyethylene layer 40 grams per square metre; TOTAL 61 grams per square metre.

MG C:\WINWORD\MARLO\NODELETE\CDS\PN2574.DOC Figure 3 illustrates a third embodiment wherein the laminate incorporates an open weave mesh material The large spaces which are preferably 15-20mm across and lie between the strands of the mesh allow the mesh to be trap laminated between adjacent layers. In other words, the adjacent layers bond to each other within the large spaces in the reinforcing material, thereby trapping the reinforcing material between the adjacent layers. As a consequence, only one layer of adhesive is required between the adjacent layers. If the reinforcing material had a close weave a layer of adhesive would be required between the material and one layer on one side and between the material and the other layer on the other side.

Each of the laminates described in Figures 1 to 3 exhibit a bursting force as measured according to AS2001.2.19 of greater than 220 Newtons and edge tear resistance as measured by AS4200.1 in both the machine and lateral directions of the laminated sheet of more than 60 Newtons.

The invention shall now be described with reference to the following example:

EXAMPLE

Aquabond 444 was applied to one face of 1300 mm wide polyethylene terephthalate (PET) film having a weight of 17 grams per square metre. The dry weight of adhesive as applied to this film is 3 grams per square metre. The adhesive is dried using hot air at 1000C. Thereafter aluminium foil having a weight of 17 grams per S: square metre is laminated to the adhesive coated PET layer by passing these layers S through a web fed dry laminating machine at the rate of 100 150 metres per minute.

The laminating nip rollers in the machine are heated to 70'C to enhance the bond between the PET and foil layer. Thereafter, a 1300 mm wide blown polyethylene film having a weight of 40 grams per square metre is obtained. The film has the following characteristics. The film is rendered opaque by the addition of a colorant and matting agent to the polymeric material of the film and the oxidation resistance of the film is increased by the addition of 500 ppm Irganox 1010 to the polymeric material of the film.

Furthermore, the film is corona discharged treated to enhance the bonding of the adhesive to the film. Aquabond 444 is applied to the PET face of the PET/foil layer the dry weight of the adhesive as applied being no greater than 3 grams per square metre.

The adhesive is air dried at 1000C and the PET/Foil layer and blown polyethylene film MC C:\WINWORD\MARLO\NODELETE\CDS\PN2574.DOC polyethylene film are fed into a web fed laminating machine and laminated together.

The nip rollers of the laminating machine are heated to 70'C to enhance the bond between the PET layer and polyethylene layer. The PET/foil layer and blown polyethylene layer are fed into the laminating machine in substantially the same direction as the laminate exits the machine so that the machine direction of the PET film and blown polyethylene film in the laminate extend in the same direction and in the same direction as the machine direction of the laminate sheet itself.

To install the reflective laminate product of this invention, the laminate sheet can be affixed to the frame of the walls or the rafter or joists of a roof by nails, staples or the like.

The advantage of the present insulation sheet of this invention over known reflective insulation sheets is that it is light weight yet strong. A further advantage of the insulation sheet of this invention is that it need not include a paper layer. Accordingly, the insulation may function as a vapour barrier and water barrier, and is resistant to wetting.

Finally, it is understood that various alterations, modifications and/or additions may be introduced into the construction and arrangement of the insulation sheet previously described without departing from the spirit or ambit of the invention.

MC C:\WINWORD\MARLONODELETE\CDS\PN2574.DOC 11

Claims

1. A reflective insulation laminate sheet including: one or more layers of a first polymeric material having a bursting force value of equal to or greater than 100 Newtons and a tensile modulus value of equal to or grater than 15 kilonewtons per metre; and one or more layers of a second polymeric material having a propagation tear resistance value of equal to or greater than 0.25 Newtons, wherein at least one face of the laminate sheet has an overall infrared emittance not greater than 0.08 and the overall weight of the laminated sheet does not exceed 180 grams per square metre.

2. The laminated sheet according to claim 1 wherein the one or more layers of o first polymeric material and the one or more layers of second polymeric material are o laminated together so that the machine directions of these layers extend substantially se** in the same direction and in the same direction as the laminated sheet itself. .0.15

3. The laminated sheet according to claims 1 or 2 wherein the bursting force value is equal to or greater than 200 Newtons, the tensile modulus value is equal to or greater than 25 kilonewtons per metre and the propagation tear resistance value is equal to or greater than 0.50 Newtons. i= °o

4. The laminated sheet according to any one of claims 1 to 3 wherein the one or 20 more layers of first polymeric material have a total weight of between 9 and 50 grams per square metre and the one or more layers of second polymeric material have a total weight of between 20 and 120 grams per square metre.

The laminated sheet according to claim 4 wherein the one or more layers of first polymeric material have a total weight of between 15 to 25 grams per square metre and the one or more layers of second polymeric material have a total weight of between 25 to 50 grams per square metre.

6. The laminated sheet according to any one of the preceding claims wherein the sheet has a total weight of between 4 and 150 grams per square metre.

7. The laminated sheet according to claim 6 having a total weight of about grams per square metre.

8. The laminated sheet according to any one of the preceding claims wherein the first polymeric material is selected from the group of polymeric materials consisting of L~/ w oriented polyester film, oriented polypropylene film, oriented nylon film, cast polypropylene film and cast polyvinylchloride film.

9. The laminated sheet according to claim 8 wherein the oriented polyester film is made from polyethylene terephthalate.

10. The laminated sheet according to any one of the preceding claims wherein the second polymeric material is selected from the group of polymeric materials consisting of blown or cast polyethylene film, blow or cast polyethylene/polypropylene copolymer film, ethylene vinylacetate film, copolymer nylon film, ionomer film, acid copolymer film and plasticised polyvinylchloride film. 0

11. The laminated sheet according to claim 10 wherein the layer of second polymeric film is blown polyvinylchloride film.

12. The laminated sheet according to any one of the preceding claims wherein the sheet has a bursting force value of greater than 200 Newtons and an edge tear 0s* resistance value of more than 45 Newtons.

13. The laminated sheet according to any one of the preceding claims wherein the ."0 laminated sheet includes a further layer that confers the specified infrared emittance property on the laminated sheet, the further layer being a metal foil layer or a metallised deposit layer.

14. The laminated sheet according to any one of the preceding claims wherein the SO• 0 sheet includes a reinforcing fabric layer. 0.0:

15. A reflective insulation laminate sheet including: .0900 a layer of aluminium foil having a weight of about 17 grams per square metre; an adhesive layer; a layer of polyethylene terephthalate film having a weight of between t6 25 grams per square metre; an adhesive layer; and a layer of blown polyethylene film having a weight of between 25 to grams per square metre, the blown polyethylene film including a colorant and matting agent; wherein the overall weight of the laminated sheet does not exceed 180 grams per square metre.

16. A method of manufacturing a reflective insulation laminate sheet including taking: one or more layers of a first polymeric material having a bursting force value of equal to or greater than 100 newtons and a tensile modulus value of equal to or greater than 15 kilonewtons per metre; and one or more layers of a second polymeric material having a propagation tear resistance value of equal to or greater than 0.25 newtons, and conveying said layers of first and second polymeric materials into a laminating machine and laminating said layers together to form a laminated reflective insulation sheet, wherein said layers of polymeric materials are conveyed into said machine in substantially the same direction that the laminated sheet exits the machine so that the machine directions of the layers of polymeric material in the laminated sheet a. extend in substantially the same direction and in substantially the same direction as the i:0 machine direction of the laminate sheet itself, said laminate also having at least one face having infrared emittance not greater than 0.08 and the overall weight of said laminated sheet not exceeding 180 grams per square metre.

17. The method according to claim 16 wherein the laminated sheet includes a further layer that confers the specified infrared emittance property on the laminated sheet and the method further includes the step of laminating this further layer to either the one or more layers of first polymeric material or the one or more layers of second polymeric material.

18. A laminated sheet according to any one of the preceding claims as illustrated in any one of the figures and as disclosed in the example. DATED:

19 April, 1996 PHILLIPS ORMONDE FITZPATRICK Attorneys for: ACI AUSTRA LI= A LTD 0 Ampt xs MT MC C:\WINWORD\MARLO\NODELETECDS\PN2574.DOC