WO2011017758A1

WO2011017758A1 - Reflective heatshrinkable film

Info

Publication number: WO2011017758A1
Application number: PCT/AU2010/001026
Authority: WO
Inventors: Rodney Burge; Adam Farrow
Original assignee: Storm Holding (Aust) Pty Ltd
Priority date: 2009-08-14
Filing date: 2010-08-13
Publication date: 2011-02-17

Abstract

A reflective heat-shrinkable film for weatherproofing or protection from detrimental effects of heat and light of articles; said film comprising a heat-shrinkable polymer film; said heat-shrinkable polymer film provided with a deposited metallic reflective layer. In a particularly preferred form, the film is structured as an aluminium layer between two electrically insulating layers.

Description

REFLECTIVE HEATSHRINKABLE FILM

The present invention relates to a protective reflective film for insulation from light and heat energy transmission and, more particularly, to a heat-shrinkable film with these properties.

BACKGROUND

The application of a heat-shrinkable polymer film to the damaged roof of a building or to the framing of a building under construction, as well as for the protecting other items is known. Thus a method of preventing ingress of rain through a damaged roof for example is disclosed in US2005/0217202. The use of strips of such heat shrinkable films, assembled into a protective sheet at ground level prior to application, either to a damaged roof or walls, or as a permanent sarking layer was disclosed by the present applicant in AU2008203409 and PCT/AU2009/000685 for example .

A disadvantage of the use of a standard heat- shrinkable film as a sarking layer is that such films are typically transparent to both the visible and infrared parts of the spectrum. Thus, although effective in protecting a building under construction, or in providing cover for a damaged roof from the effects of weather, the film is ineffectual as a barrier to heat and light. These disadvantages also apply in all cases where the use of heat shrinkable film is advantageous in protecting items exposed to weather but may suffer from excessive heat build-up.

It is common practice to use heat-shrinkable film for packaging of items, but can offer no protection from effects of light and heat, particularly to perishable food items and other articles subject to deterioration from prolonged exposure to light and heat.

It is an object of the present invention to address or at least ameliorate some of the above disadvantages.

Notes

1. The term "comprising" (and grammatical variations thereof) is used in this specification in the inclusive sense of "having" or "including", and not in the exclusive sense of "consisting only of".

2. The above discussion of the prior art in the Background of the invention, is not an admission that any information discussed therein is citable prior art or part of the common general knowledge of persons skilled in the art in any country.

BRIEF DESCRIPTION OF INVENTION

Accordingly, in a first broad form of the invention, there is provided a reflective heat-shrinkable film for weatherproofing=or protection from detrimental effects of heat and light of articles; said film comprising a heat- shrinkable polymer film; said heat-shrinkable polymer film provided with a deposited metallic reflective layer.

Preferably, said deposited metallic reflective layer is deposited by a physical vapour deposition process.

Preferably, said physical vapour deposition of said metallic reflective layer is by evaporative deposition.

Preferably, said physical vapour deposition of said metallic reflective layer is by electron beam deposition.

Preferably, said metallic reflective layer comprises a deposited layer of aluminium.

Preferably, a protective top coat is applied over said deposited metallic reflective layer; said top coat resistant to damage to said layer.

Preferably, said heat-shrinkable polymer film is a low-density polyethylene film.

Preferably, said deposited layer of aluminium has a thickness of between 250 and 400Angstrδm.

Preferably, said film is adapted for weather-proofing a damaged or under-construction building.

Preferably, said film is adapted for heat insulation of a framed building; said film providing a permanent sarking layer for said building.

Preferably, said film is located between a frame of said building and an outer skin of said building. Preferably, said film is located between framing of a roof and roof cladding of a said building.

Preferably, said film is located over a damaged portion of a said building.

Preferably, heat applied to said film subsequent to fixing to a said building, shrinks said film into close conformity with surfaces defined by said framing.

In another broad form of the invention, there is provided a method of reducing transmission of light and heat through a heat-shrinkable weatherproofing film; said method includes the steps of:

(a) providing heat-shrinkable polymer film with a metallic reflective layer,

(b) adding a protective top coating over said metallic reflective layer,

Preferably, said method includes the steps of vapour deposition of said metallic reflective coating; said method includes the steps of:

(a) loading a roll of said polymer film into a vacuum deposition chamber,

(b) inducing high vacuum within said chamber,

(c) heating of the aluminium vapour deposition evaporation boats,

(d) advancing aluminium source material through said evaporation boats, (e) advancing said polymer material over said evaporation boats.

Preferably, said of vapour deposited aluminium is by an electron beam process.

Preferably, said reflective heat-shrinkable film is applied to a damaged part of a roof of said building.

Preferably, said selected area is a portion of the framing of a roof of a building under construction.

Preferably, said reflective heat-shrinkable film is applied to a portion of the wall framing of a building under construction.

Preferably, said metallic metal coating is a layer of vapour deposited aluminium applied to a surface of said heat-shrinkable polymer film.

In still another broad form of the invention there is provided metallised heat-shrinkable polymer film; said film including a layer of vapour deposited metal and a top coat protecting said layer; said film adapted for packaging of items subject to detrimental effect of light and/or heat .

BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the present invention will now be described with reference to the accompanying drawings wherein: Figure 1 is a schematic sectioned view of a metal vapour deposition device for deposition of a reflective film according to a preferred process of the invention,

Figure 2 illustrates a preferred method of application of the reflective film produced in the manner of Figure 1 for application to a damaged roof of a building or to the roof framing of a building under construction,

Figure 3 shows the frame of a building under construction to which a first band of the reflective sarking film of the invention has been applied.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The reflective sarking film of the present invention comprises a polymer heat shrinkable material to which has been applied a thin metallic reflective layer. Deposition of the metallic layer is preferably by evaporative physical vapour deposition but may be by electron beam deposition or other suitable methods.

The combined properties of heat shrinkage and high reflectivity provided by the reflective layer, makes the film of the invention highly suitable, for example, for applications in weatherproofing a damaged building or building under construction, and also as a permanent insulating sarking layer over roof and wall framing. Preferably, the heat shrinkable film is a low density polyethylene between 0.15 and 0.50mm in thickness and provided in rolls of a width in one form up to 1550mm and in another form up to 4.5 m. Preferably, the heat- shrinkable film includes UV inhibitors, anti-brittling, strengthening compounds as well as shrinking resins and fire retardants.

In a preferred embodiment, the metallic reflective surface is of aluminium, although the method of layer deposition on the film of the invention may use other metals .

A roll of film is prepared for use by application of the metallic reflective layer to one side of the film by the process of physical vapour deposition. In a preferred arrangement of a vapour deposition device 10 as shown in Figure 1, a roll of film 12 is placed into an automatic loading device (not shown) which transfers the roll into the vacuum chamber 14 of the vapour deposition device 10. When sealed, a hard vacuum is induced in the chamber 14 while at the same time, the aluminium evaporation sources 16 or "boats", are brought up to temperature.

The aluminium source, in the form of aluminium wire 18, is fed to the evaporation sources 16 once these are up to the required temperature and the vacuum level has been reached. To ensure even coverage of the film, the system employs a metalliser 1670mm in width, with sources 16 spaced over the width of the film 12.

The film is advanced at high speed at some 150mm above the line of evaporation sources 16. These sources then provide a condensate of aluminium to adhere to the surface of the passing film 12. Adhesion of the condensate to the film, is assisted by passing the film over a drum 19 chilled to -IOdegrees C. The deposited aluminium vapour has a thickness of between 250 and 400Angstrδm.

Metallised film 20 is taken up by a rewind mandrel 22. At the completion of each roll, the vacuum in the chamber 14 is broken and the evaporation sources 16 allowed to cool. In a final step in the process, the now metallised film is transferred to a coating machine (not shown) and provided with a top coat preferably of acrylic of thickness preferably in range 3-5 microns over the metallic layer to protect the aluminium from oxidation and scuffing. Electron beam curing of the top coat avoids the use of environmentally damaging Volatile Organic Compounds (VOCs) nor produces Hazardous Air Pollutants (HAPs) .

In a particularly preferred form, the top coat includes electrically insulating materials thereby to render the entire sheet electronically non-conductive. Tests have shown that this structure which basically comprises a thin aluminium layer sandwiched between two insulating layers (the polar film and the top coat continues to act as an insulator even where the top coat may be damaged for example by scratching) .

As shown in the insert in Fig. 2 the structure comprises the lower insulating layer A comprising polyethylene film of thickness typically in the range 20nm - 40nm overlaid with the deposited aluminium layer B typically in the range 250 - 400 Angstrom and which in turn is overlaid with the top coat, typically of insulating acrylic having a thickness in the range 3-5 microns.

For some applications, in a further step air vents 116 are provided at intervals along the film as shown in Figure 2. Vents provide for air circulation when the film is applied over a damaged roof or as a permanent sarking layer over roof framing.

In Use

Because the film used in embodiments of the invention preferably has very smooth surfaces, the layer of aluminium which overlays the film provides a mirror-like finish which renders the film both opaque and provides it with a very high degree of reflectivity and, hence with excellent thermal insulating properties.

When used, for example, to weatherproof a damaged or under construction building as shown in Figures 2 and 3, these properties provide privacy, and more importantly, a significant reduction in the transmission of heat energy into the building. The latter of course applies also when the film is used as a permanent reflective sarking layer 210 applied to the framing 212 of a building 200 as shown in Figure 3. In this case the reflective sarking film is applied to the framing prior to the exterior skin or cladding, which may typically be brick. In preferred forms, the reflective sarking film may be applied to the framing of a roof prior to the application of battens for the support of roofing tiles or metal roof cladding.

Depending on the extent of damage 110 to the roof 100 of a building in Figure 2, the weatherproofing reflective film 112 of the invention may first be prepared at ground level as shown in Figure 2. Two or more strips of film 112 are cut from a roll 114 and joined at their edges with a suitable tape before being taken up onto the roof and fixed in position.

In at least some embodiments, in order to improve shear strength characteristics, a contact adhesive can be used in conjunction with the tape to hold the film.

The heat-shrinkable metallised film of the invention clearly offers significant advantages in the packaging of items which may be affected by heat and light. As noted above, the principles of the metallising of a heat- shrinkable polymer film according to the invention, may be applied to metals other than aluminium, thus offering a range of attractive appearances for packaging applications. The above describes only some embodiments of the present invention and modifications, obvious to those skilled in the art, can be made thereto without departing from the scope of the present invention.

Claims

1. A reflective heat-shrinkable film for weatherproofing or protection from detrimental effects of heat and light of articles; said film comprising a heat- shrinkable polymer film; said heat-shrinkable polymer film provided with a deposited metallic reflective layer.

2. The film of claim 1 wherein said deposited metallic reflective layer is deposited by a physical vapour deposition process.

3. The film of claim 2 wherein said physical vapour deposition of said metallic reflective layer is by evaporative deposition.

4. The film of claim 2 wherein said physical vapour deposition of said metallic reflective layer is by electron beam deposition.

5. The film of any one of claims 1 to 4 wherein said metallic reflective layer comprises a deposited layer of aluminium.

6. The film of any one of claims 1 to 5 wherein a protective top coat is applied over said deposited metallic reflective layer; said top coat resistant to damage to said layer.

7. The film of any one of claims 1 to 6 wherein said heat-shrinkable polymer film is a low-density polyethylene film.

8. The film of claim 5 wherein said deposited layer of aluminium has a thickness of between 250 and 400Angstrδm.

9. The film of any one of claims 1 to 8 wherein said film is adapted for weather-proofing a damaged or under- construction building.

10. The film of any one of claims 1 to 8 wherein said film is adapted for heat insulation of a framed building; said film providing a permanent sarking layer for said building.

11. The film of claim 10 wherein said film is located between a frame of said building and an outer skin of said building.

12. The film of claim 10 wherein said film is located between framing of a roof and roof cladding of a said building.

13. The film of claim 9 wherein said film is located over a damaged portion of a said building.

14. The film of any one of claims 10 to 12 wherein heat applied to said film subsequent to fixing to a said building, shrinks said film into close conformity with surfaces defined by said framing.

15. A method of reducing transmission of light and heat through a heat-shrinkable weatherproofing film; said method includes the steps of: (a) providing heat-shrinkable polymer film with a metallic reflective layer,

(b) adding a protective top coating over said metallic reflective layer,

16. The method of claim 15 wherein said method includes the step of vapour deposition of said metallic reflective coating; said method includes the steps of:

(a) loading a roll of said polymer film into a vacuum deposition chamber,

(b) inducing high vacuum within said chamber,

(c) heating of the aluminium vapour deposition evaporation boats,

(d) advancing aluminium source material through said evaporation boats,

(e) advancing said polymer material over said evaporation boats.

17. The method of claim 16 wherein said of deposition of vapour deposited aluminium is by an evaporative deposition process.

18. The method of any one of claims 15 to 17 wherein said reflective heat-shrinkable film is applied to a damaged part of a roof of said building.

19. The method of claim 18 wherein said selected area is a portion of the framing of a roof of a building under construction.

20. The method of any one of claims 15 to 17 wherein said reflective heat-shrinkable film is applied to a portion of the wall framing of a building under construction.

21. The method of any one of claims 15 to 20 wherein said metallic metal coating is a layer of vapour deposited aluminium applied to a surface of said heat- shrinkable polymer film.

22. The method of any one of the claims 16-21 further including the application of a non electrically conductive coating.

23. A metallised heat-shrinkable polymer film; said film including a layer of vapour deposited metal and a top coat protecting said layer; said film adapted for packaging of items subject to detrimental effect of light and/or heat.

24. The film of any one of claims 1-14 or claim 23; said film including an externally applied, non

electrically conductive coating thereby to render the film non electrically conductive.