NZ248286A

NZ248286A - Reflective insulation material with moisture absorbent backing and waterproof coating

Info

Publication number: NZ248286A
Application number: NZ24828693A
Authority: NZ
Inventors: Francis Vaughan Evans
Original assignee: Carter Holt Harvey Building
Priority date: 1993-07-29
Filing date: 1993-07-29
Publication date: 1996-11-26
Also published as: AU657459B3

Description

Patents Form #5 2 4 q ? Q (5 r> J13 !■'= 1994 "if NEW ZEALAND Patents Act 1953 rOMPT .RTF, SPECIFIC ATTON TTTTJR: Reflective Insulation Sheet Material We, Carter Holt Harvey Building Products Group Limited, a New Zealand company, of 22 Greenpaik Road, Penrose, Auckland, New Zealand, hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: PF05.JWP FEE CODE - 1050 2*8286 ABSTRACT OF THE DISCLOSURE A sheet of aluminium foil 11, has an exposed reflective surface 12 and a covered surface 13 bonded by a layer of adhesive 14 to a reinforcing mesh IS, typically of fibre glass or polyester yam. The adhesive 14 passing through the interstices in the mesh 15 also bonds the latter and the foil 11 to a first face 16 of a sheet of moisture-absorbent material 17, typically fibrous material such as kraft paper or other porous material. A second face 18 on the other side of the material 17 from the first face 16 is coated with a water-proof, flame retardant synthetic polymer coating having substantial moisture vapour permeability to provide the required properties to pass water vapour but to act as a barrier to water and wind driven rain. The sheet of moisture absorbent material provides a layer which is substantially thicker than the foil layer to provide sufficient bulk to allow this layer to absorb any moisture condensate formed on or near the interface between the foil and paper and to allow the moisture to be released back to the environment during a later warmer or drier time.

* * * * * ♦ FIELD This invention relates to reflective insulation sheet material.

BACKGROUND It is well known to use aluminium foil sheet material or membrane in buildings to increase the thermal insulation thereof by reducing radiant heat transmission through the wall or roof in which the foil is incorporated.

However, any sudden and rapid change in temperature may cause condensation on one surface of the aluminium or other moisture vapour impermeable membrane. The condensation leads to water ponding and subsequent run off and water damage to the construction materials. *702C41.«94/at 24 8 28 6 As a consequence of these disadvantages, there is currently doubt as to whether it is better to use a reflective aluminium foil sheet material, having virtually zero moisture vapour transmission rate or a moisture vapour permeable membrane having inferior 5 radiant energy insulation properties. Such moisture vapour permeable membranes allow the passage of moisture from high humidity zones, usually within the building.

OBJECT It is an object of the present invention to overcome some of these difficulties. STATEMENT OF INVENTION According to one aspect of the present invention, there is provided a reflective 15 insulation sheet material, including a sheet of metal having a first surface which is an exposed reflective surface, a second surface on the opposite side of the sheet of metal, and a sheet of moisture absorbent material carried by said second surface, to absorb moisture condensed on or near the second surface, and in which a surface of the sheet of moisture absorbent material remote from the sheet of metal is coated with a 20 waterproof moisture vapour permeable coating.

Such a coating would allow the passage of water vapour therethrough whilst acting as a barrier to liquid water and wind driven rain.

A reinforcing mesh may be bonded to said second surface or to a surface between said second surface and the sheet of moisture absorbent material.

The coating is conveniently a synthetic polymer having substantial moisture vapour permeability.

DRAWINGS Various embodiments of the present invention are described, by way of example only with reference to the accompanying drawings which are of a diagrammatic pnly 35 and in which: .

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K 10 OCT 1996 -7; O / 6702ICS2.096/CW/iv ~ v- * \t ' Figure 1 is a cross-section at enlarged scale of part of a reflective insulation sheet material according to the invention, and Figure 2 shows an alternative embodiment to Figure 1, PREFERRED EMBODIMENT In Figure 1, a sheet of reflective insulation sheet material 10 is used to separate a zone A from a zone B which may have a higher relative humidity than zone A.

A sheet of metal foil 11, usually aluminium, has an exposed reflective surface 12 and a covered surface 13 bonded by a layer of adhesivel4 to a reinforcing mesh IS, typically of fibre glass or polyester yarn. The adhesive 14 passing through the interstices in the mesh 15 also bonds the latter and the foil 11 to a first face 16 of a sheet of water-absorbent material 17, typically fibrous material such as kraft paper or other porous material A second face 18 on the other side of the material 17 from the first face 16 is coated with a water-proof or water-repellent coating 19 of a kind which is permeable to water vapour. A suitable synthetic polymer such as a modified polyvinylchloride and all latex emulsions, particularly those containing chlorine, provide the required properties to pass water vapour but to act as a barrier to water and wind driven rain. The coating 19 may conveniendy be applied by roller.

The construction shown in Figure 2 is substantially as shown in Figure 1 except that a further layer of adhesive 20 bonds the surface 13 of the metal foil 12 to a reinforcing and absorbent sheet 21 of kraft paper or the like, which is bonded in turn by the adhesive layer 14 to the mesh 15, as before.

In use, for example, in typical roof and wall cavity situations, when the atmospheric characteristics such as temperature, pressure and relative humidity are appropriate, water vapour from zone B will pass through the coating 19 and the material 17 and condense on or near the metal sheet 11. However, instead of collecting and running down the sheet 10, the water condensate is absorbed locally by the material 17 and retained therein, to be released back to the atmosphere during a subsequent warm, dry 6702CS1.694/ftt period.

Because of potential flammability, and particularly in order to achieve a flammability index of less than 5 when tested to Australian Standard AS1530:2 1973, the relevant components and especially the adhesive 14,20 reinforcing sheet 21, the material 17 and the coating 19 are all made of or incorporate flame retaidant components, know per se.

If required the metal sheet 11 may be punctured with many small holes to allow water vapour to pass therethrough.

Finally, it will be appreciated that various alterations or modifications may be made to the foregoing without departing from the scope of this invention as claimed. 6702CS1.694/at 24 8 2 8 6

Claims

WHAT WE CLAIM IS:

1. A reflective insulation sheet material, including a sheet of metal having a first 5 surface which is an exposed reflective surface, a second surface on the opposite side of the sheet of metal, and a sheet of moisture absorbent material carried by said second surface, whereby in use the moisture absorbent material can absorb moisture condensed on or near the second surface, and in which a surface of the sheet of moisture absorbent material remote from the sheet of metal is coated with a waterproof moisture vapour 10 permeable coating.

2. A reflective insulation sheet material, as claimed in claim 1 wherein the moisture absorbent material provides a layer which is substantially thicker than the metal layer to provide sufficient bulk to allow this layer to absorb any moisture 15 condensate formed on or near the second surface and to allow the moisture to be released back to the environment during a later warmer or drier time.

3. A reflective insulation sheet material, as claimed in claim 1 or claim 2, wherein said moisture absorbent material consists of kraft paper or 20 an absorbent fibreboard.

4. A reflective insulation sheet material, as claimed in claim 1 or claim 2, wherein said moisture absorbent material consists of chemically treated flame retardant kraft paper. 25

5. A reflective insulation sheet material, as claimed in any one of claims 1-4, wherein said sheet of metal comprises a layer of metal foil.

6. A reflective insulation sheet material, as claimed in claim 5, wherein said foil 30 is a single layer of aluminium foil.

7. A reflective insulation sheet material, as claimed in claim 6, wherein said aluminium foil layer is punctured with small holes to allow moisture vapour to pass equally in both directions. <"■% £ *'i t ' J:' ■ > '■ o /> TO OCT 1936 v % ^ ■ 6702ICS2.096/CW/iv , ' \ 248 28 6 -7-

8. A reflective insulation sheet material, as claimed in any one of claims 1 to 7, wherein said coating is adapted to allow the passage of water vapour therethrough whilst acting as a barrier to liquid water and wind driven rain.

9. A reflective insulation sheet material, as claimed in claim 8, wherein said coating is a synthetic polymer having substantial moisture vapour permeability.

10. A reflective insulation sheet material, as claimed in claim 9, wherein said 10 coating is also a flame retardant coating.

11. A reflective insulation sheet material, as claimed in any one of claims 1-10, wherein a reinforcing mesh is bonded to said second surface or to a surface between said second surface and the sheet of moisture absorbent material.

12. A building containing one or more layers of a reflective insulation sheet material, as claimed in any one of claims 1-11.

13. A flame retardant reflective foil laminate material substantially as herein

14. A reflective insulation sheet material, substantially as herein descried with reference to anyone of the accompanying drawings. 5 15 20 described. 25 30 fey Building Products Group Limited 35 ■J — otj 10 nnt mac w