A batt for an insulation panel and an insulation panel

Abstract

A batt for an insulation panel to provide a low carbon, recyclable alternative to traditional insulation such as fibreglass. The batt comprises spaced flat insulating layers 3 forming side. At least one of these is metallised. The layers are separated by an open cellular layer 2 to define a plurality of cells, which are closed by the first and second layers to define walls of the cells. Additional layers may be provided for example to enhance noise attenuation, moisture proofing, or fire resistance.

Description

[0001] A Batt for an Insulation Panel and an Insulation Panel

[0002] The present invention relates to a batt for an insulation panel and an insulation panel.

[0003] In particular, it is designed as an insulation panel for use in buildings. Conventional insulation in buildings uses insulation batts which are large sheets of fibreglass, mineral wool, polyisocyanurate or extruded or expanded polystyrene. These are placed in cavities, for example in wall, floor or roof panels or joists in order to insulate a building.

[0004] While these materials have excellent insulating properties, they do have some drawbacks. They require high levels of energy to produce as the rock or glass has to be in a molten state to produce the fibres. Further, the fibres are a potential health hazard meaning that precautions are required during installation. The fibres are also not readily recyclable.

[0005] While the invention is primarily intended for construction, it also has application in other areas such as packaging, aeronautics, shipping, transport (e.g. containers requiring refrigeration) power generation / heat distribution, food and beverage, IT (e.g. computing farms or data centres).

[0006] US 2019 / 0048579 discloses an insulation batt in which the conventional fibreglass material is contained by a stiffening layer which may be formed of corrugated cardboard. This suffers from the above problems associated with fibre glass as well as introducing additional complexity.

[0007] A product made by Actis under the name Hybris discloses a honeycomb structure with multiple layers of undulating oil based material separated by flat layers. This provides a lightweight insulation batt. The present invention aims to provide an improved batt.

[0008] According to a first aspect of the present invention, there is provided a batt for an insulation panel according to claim 1 .

[0009] In contrast to US 2019 / 0048579, the batt uses metallised layer and open cellular layer rather than a mineral wool / fibreglass fibrous layer. This avoids the hazard and cost of manufacture associated with the prior art. Further, its carbon footprint is significantly

[0010] 17015683.EAM.EAM reduced as it requires significantly less energy to produce, can be made from recycled material and can, itself, be recycled.

[0011] In Hybris, the walls of the cellular layer run lengthways along the batt. In the present invention they run perpendicular to this. Placing the side walls perpendicular to the cellular structure allows the creation of small, enclosed cells, creating an improved thermal resistance by allowing the cells to be of a size that inhibits the movement of air, rendering the air to be an excellent insulating medium. By contrast, in Hybris there are channels running the length of the batt resulting in significant air movement within the batt.

[0012] In addition the structural integrity of the batt is enhanced meaning that the same structural performance can be achieved with less material. This reduces the weight and cost of the batt and improves its insulation properties as there is less material forming potential conductive paths across the batt.

[0013] The batt provides low cost, lightweight and efficient insulation as the cellular layer creates an air gap between the two flat insulating layers while the metallised layer reflects heat or coolth. The cellular layer creates a thermal bridge across the batt. However as the flat layers are insulating layers, this mitigates the effect of the small amount of heat conducted through the cellular layer.

[0014] The batt preferably has a U value of less than 0.6 W / m2K and preferably less than 0.5 W / m2K. The U value is a well-known indication heat loss through the material. This is obtained by dividing the temperature difference inside and outside of the batt by the rate of heat transfer through the batt. This is measured using the British standard heat flow method.

[0015] At least one of the first and second flat layers preferably has a thermal conductivity of less than 0.05W / mK and preferably less than 0.04 W / mK. This low thermal conductivity in the flat layers mitigates the effect of the small amount of heat conducted through the cellular layer.

[0016] The flat layers may be of any suitable insulating material. However, at least one of the first and second flat layers preferably comprises a cork layer. Not only is cork an excellent insulator (with a thermal conductivity of 0.038W / mK) it is also fire resistant and has good

[0017] 17015683.EAM.EAM sound absorption properties. Alternatively or additionally the insulating material may include cellulose or bamboo fleece.

[0018] To further reduce the carbon footprint of the batt, at least one of the first and second flat layers is preferably a non-carbon based insulating material.

[0019] The metallised layer may be a metal foil which may be used in its own or as part of a laminate. Alternatively, it may be a metal coated substrate. The metal may be a metal such as copper, titanium, silver or gold. The material can be selected depending on the required use of the batt to give greater heat or thermal protection. Aluminium offers a good balance between cost and performance. It is also readily recyclable. Aluminium foil reflects about 95% of the infrared heat that hits its surface and blocks the flow of radiation, making it useful in preventing heat loss. Aluminium foil has unique properties due to the fact that it is extremely thin and very shiny. It may be beneficial to use different foils on the two sides. For example, gold can be used on the hot side and aluminium on the cold side.

[0020] One or both flat layers may be metal foil. These may be adhered to the open cellular layer and just provided on the main faces. Alternatively, the open cellular layer may be fully surrounded on all sides by the metal foil. This can be done by attaching the foil separately to all sides or wrapping the batt in the foil.

[0021] If the batt is to be used in an environment in which it will be exposed to moisture, it is preferably wrapped in a moisture proof film. The batt could be wrapped in the foil and the moisture proof or resistant film. However, in this case, the metal foil may be confined to the main faces of the batt as there is no need for it to fully surround the batt.

[0022] The film can provide a gas tight seal for the batt. This improves the insulation properties and allows the batt to be filled with a gas such as carbon dioxide. This can be beneficial as it provides carbon capture. CO2 is heavier than air and more viscous so it increases the thermal resistance of the batt thereby improving thermal efficiency. In the event of a fire, the CO2 helps to suffocate the fire.

[0023] Alternatively, the internal space of the batt is at a pressure lower than atmospheric pressure. This creates a partial vacuum which can enhance the insulation performance of the batt.

[0024] 17015683.EAM.EAM The batt may also contain sodium bicarbonate. When this burns it gives off CO2 which again will act as a fire suppressant.

[0025] The batt is preferably configured such that there is no air path across the depth of the batt which is greater than 45mm preferably 25mm, more preferably 23mm and most preferably 20mm. Ensuring that any path across the depth of the panel is smaller than 45mm, reduces the air convecting thereby ensuring that the insulating properties of the panel are maintained. The smaller this dimension is, the greater the reduction in convention.

[0026] In plan, the internal walls of the cells preferably fit within a circle with a diameter of 30mm, preferably 25mm and more preferably 20mm.

[0027] The open cellular layer may be a cementitious material, or an amalgam of recycled materials to create a material or product, comprising a minimum of 70% recycled material. The open cellular layer is preferably a fibrous card layer. This may be one or more of cardboard or cardboard-like material such as a natural fibrous material made, for example, of cellulose, hemicellulose, lignin cereal stem or straw, wood fibre and / or bamboo. These can form a honeycomb structure which improves the rigidity of the panel. Such honeycomb structures are known in packaging but have fibrous outer layers. By replacing these with foil, the heat transfer by conduction is greatly reduced leading to an efficiency improvement by a factor of around 3 of 4.

[0028] Once heated in a fire, many thermoplastics can generate dripping flame. These dripped plastics can flow like a liquid fuel and form a pool fire. The dripping of thermoplastic fuels is a significant fire hazard even acting as an accelerant. Cellulose, cellulose based products and metal or metallised products do not burn in this way. Cellulose fibers also have a good fire resistance.

[0029] The walls of the cells may have a metal lining e.g. a metal foil. This may be of the same type that is used for the flat layer(s). This creates a cellular structure in which the metal lining reflects heat internally within the cells which enhances the insulation properties. The foil is a thin layer such any conductive effect that it creates across the batt is more than offset by the internal heat reflection.

[0030] 17015683. EAM. EAM The metal foil may be single metal layer. Alternatively, it is a laminate of at least one metal layer and a cellulose layer.

[0031] The wall thickness of the material forming the open cellular layer has to strike a balance between structural rigidity and thermal conductivity. The fact that the walls of the cellular layer run perpendicular to the side walls provides excellent structural integrity. This allows the walls of the cellular to be particularly thin. This reduces the width of the batt and reduces the potential thermal bridges across the batt. The walls of the cellular layer are preferably less than 3mm, more preferably less than 02 mm and most preferably less than 1 mm thick. If the walls are laminates, this represents the total thickness of all of the layers. When a foil is used, this will be 6 microns to 160 microns thick. The walls may be made by bonding rows of folded strips together. In this case the walls of the cellular layer (other than the outermost walls of the outermost cells) are twice the thickness of the thickness of the folded strips.

[0032] All of the materials are preferably recyclable.

[0033] The invention also extends to an insulation panel formed of at least one batt according to the first aspect of the invention arranged on top of one another.

[0034] The batts may be directly adjacent to one another. Alternatively adjacent batts may be separated by spacers. This provides a way of creating air gaps between adjacent layers which enhances the insulation of the panel at very little additional cost. Also, it allows batts to be produced with a fixed thickness. In this case, the batts can be mass produced in various standard thicknesses. Alternatively or additionally when a panel of a certain thickness is required, a number of fixed thickness panels can be stacked together, and spacers can be selected to give the required panel thickness. This way, the batts themselves do not need to be bespoke for each panel.

[0035] The spacers may be made of any suitable material such as wood. However, preferably the spacers are formed as an open cellular layer, for example a laminated fibrous card structure comprising first and second spaced flat card layers separated by an undulating layer extending between the first and second flat layers. These can be made of the same material as the batts. This is economic and easy to assemble.

[0036] 17015683.EAM.EAM The moisture proof or resistant film may be wrapped around individual batts. However, for a panel, the moisture proof film may be wrapped around more than one batt.

[0037] The batts may be arranged with their cellular layers laterally offset from one another. This creates a “tongue and groove” joint at the edge of the panel to allow adjacent panels to be interlocked.

[0038] An example of a batt and panel in accordance with the present invention will now be described with reference to the accompanying drawings, in which:

[0039] Fig. 1 is an exploded perspective view of part of a batt;

[0040] Fig. 2 is a schematic cross-section through part of a batt;

[0041] Fig. 3 is a view similar to Fig. 2 of a first panel;

[0042] Fig. 4 is a view similar to Fig. 3 of a second panel;

[0043] Fig. 5 is a view similar to Fig. 1 showing a third panel;

[0044] Fig. 6 is a view similar to Fig. 1 showing a fourth panel; and

[0045] Fig. 7 is a partial perspective view showing an alternative batt.

[0046] The batt 1 shown in Fig. 1 is made up of a honeycomb layer 2 bounded by two flat sheets 3. The honeycomb layer may consist of a cementitious material, or an amalgam of recycled materials or may be a cardboard or cardboard-like material such as a natural fibrous material made, for example, of cellulose, hemicellulose, lignin cereal stem or straw, wood fibre and / or bamboo.

[0047] At least one of the flat layers 3 are made of metal foil such as an aluminium or other suitable foil.

[0048] The flat layers 3 are bonded to the honeycomb structure 2 and the honeycomb structure 2 may be wrapped in foil which forms the two flat layers 3. This structure may be wrapped

[0049] 17015683.EAM.EAM with a moisture proof / resistant film 4, for example, of cellulose. This can create a gas tight environment within the batt. In this case, gaps may be filled with CO2. This is injected via a gas inlet indicated by arrow 5 in the bottom corner of the batt which displaces air out through vent 6 at the opposite corner of the batt. The arrow 5 and vent 6 are then sealed to form a gas tight panel. The honeycomb structure 2 is gas permeable to allow the gas replacement. The foil may be provided with gas permeable micropores or small holes such that do not affect the thermal heat transfer which accelerate this gas transfer.

[0050] The batt may contain sodium bicarbonate. This can be incorporated into the pulp processing, or be added later, for example, by being adhered to the inner face of the foil 3, or scattered / sprayed into the assembly of the honeycomb layer 2 and one foil layer 3 before the other foil layer 3 is put in place. The sodium bicarbonate may partially or fully fill each cell. These higher amounts of sodium bicarbonate can be used where increased fire resistance is of greater importance.

[0051] The layer structure of the completed batt is shown in Fig. 3 where the batt comprises the honeycomb layer 2 surrounded by foil and wrapped in moisture proof coating 4. This can be used on its own or built up into panels as shown, for example, in Figs. 3 and 4.

[0052] Fig. 3 shows a structure in which batts 1 are essentially as shown in Fig. 2 stacked directly on top of one another. In this case, two batts share a central foil layer 3 and moisture proof film 4 is applied once the two batts have been assembled together. A similar panel could be implemented with two batts each of which have foil layer 3 such that there is a double layer of foil 3 at the centre of the panel shown in Fig. 3. Alternatively or additionally, the batts could be wrapped with the moisture proof film prior to being assembled together in which case there would be layers of moisture proof film 4 at the centre of the panel in Fig.

[0053] 3.

[0054] Fig. 4 is a different design of panel. In this case two complete batts as shown in Fig. 2 have been assembled together and are separated by spacers 7. The spacers may be made of the same material as the honeycomb structure 2. As will be appreciated from Fig. 4, the thickness of the spaces can be determined in order to allow the desired panel thickness to be achieved. As shown in Fig. 4, the individual batts are wrapped in a moisture proof film. Alternatively, the moisture proof film could be applied after the batts are assembled together and the two film layers 4 at the centre of Fig. 4 would be omitted.

[0055] 17015683.EAM.EAM Depending upon the thickness of the panel, more than two layers can be assembled together using a combination of any of the above techniques optionally using spacers 7 in order to achieve the desired thickness.

[0056] As shown for example in Fig. 4 the maximum depth X of the air gap within the panel is small enough so that convection of air across the depth of the batt 1 is prevented or reduced to an acceptable degree. In order to achieve this, X (the maximum depth of the air gap) is less than 45mm, preferably less than 25 mm, more preferably less than 23 mm and most preferably less than 20 mm. The thickness of the spacers 7 should also be chosen to ensure that the air gap between the batts 1 does not exceed these numbers.

[0057] A further example is shown in Fig. 5. This comprises ten layers of honeycomb structures 2 separated by foil layers 3. The central layers are offset from the outer ones to create a tongue and grove joint at the edge of the panel to interlock with adjacent panels. The whole structure may be wrapped in a film layer or chemically or heat bonded. Alternatively individual layers or sub-units may be wrapped in film. One or more of the layers (e.g. the central layers) may be filled with a gas as described above. Alternatively, one or more of the layers may be partially evacuated.

[0058] A further example is shown in Fig. 6. This is made up of three batts each having three honeycomb layers 2 alternating with four foil layers 3 (one of which is not visible in the rearmost batt). These are separated by structural sheets 10 of metal, timber or the like.

[0059] Although these other layers can be included, the nature of the cellular material provides the function usually provided by fibreglass or mineral wool polystyrene or polyurethane thereby allowing these to be eliminated.

[0060] A batt surrounded by a wooden outer layer or metal creates a composite insulated panel which may be suitable for use in construction, shipping, aviation, transport.

[0061] Fig. 7 shows an alternative construction of the honeycomb layer 2. In this example, the strips of material forming the honeycomb structure are formed of a laminate of an inner layer 20 of card or the like bounded on both sides by a metal layer 21 . The walls of the cell (other than the outermost wall of the outermost cells) are therefore twice as thick as the

[0062] 17015683. EAM. EAM strips of material. This may be a metal coating but is preferably a metal foil attached to the inner layer before the honeycomb structure is formed. As is apparent from Fig. 7, all of the cells are lined with metal such that a significant amount of heat is reflected between the walls. Fig .7 also shows an optional sidewall 22 which may have the same properties as the foil 3 and may even be a continuation of the foal 3 around the sides of the batt.

[0063] This design allows a great deal of flexibility in designing a batt that can easily optimised for any given circumstance. The easily changeable variables available to designer include varying the thickness of the honeycomb, the number of honeycombs, the use of an air gap, the use of fire retardant materials, the selection of different metal layers and the ability to partially evacuate or change the gas within the batt.

[0064] 17015683. EAM. EAM

Claims

CLAIMS:1 . A batt for an insulation panel comprising: first and second spaced flat insulating layers forming side walls of the batt, at least one of which is metallised, the layers being separated by an open cellular layer formed of walls each with a top edge in contact with the first flat layer and a bottom edge in contact with the second flat layer, the direction between the top and bottom edges of the walls being walls being perpendicular to first and second flat layers to define a plurality of open cells, the open cells being closed by the first and second spaced flat layers to define opposing walls of the cells.

2. A batt according to claim 1 , wherein the batt has a U value of less than 0.6W / m2K and preferably less than 0.5 W / m2K.

3. A batt according to claim 1 or claim 2, wherein at least one of the first and second flat layers has a thermal conductivity of less than 0.05W / mK and preferably less than 0.04 W / mK.

4. A batt according to any preceding claim, wherein at least one of the first and second flat layers comprises a cork layer.

5. A batt according to any preceding claim, wherein at least one of the first and second flat layers is a non-carbon based insulating material.

6. A batt according to any preceding claim, wherein both flat layers are a metallised.

7. A batt according to any preceding claim, wherein the flat layers are adhered to the open cellular layer.

8. A batt according to claim 6, wherein the open cellular layer is fully surrounded on all sides by the metallised layer.

9. A batt according to any preceding claim, wherein the metallised layer is aluminium.17015683.EAM.EAM10. A batt according to any preceding claim wrapped in a moisture proof or resistant film.

11. A batt according to claim 10, wherein the film provides a gas tight seal for the batt.

12. A batt according to claim 11 , wherein the batt is filled with carbon dioxide.

13. A batt according to claim 11 , wherein the internal space of the batt is at a pressure lower than atmospheric pressure.

14. A batt according to any preceding claim wherein the batt contains sodium bicarbonate.

15. A batt according to any preceding claim, wherein the batt is configured such that there is no air path across the depth of the batt which is greater than 45mm preferably 25mm, more preferably 23mm and most preferably 20mm.

16. A batt according to any preceding claim, wherein the open cellular layer is a cardboard or cardboard-like material.

17. A batt according to claim 16, wherein walls are made from strips of card.

18. A batt according to any preceding claim, wherein the open cellular layer forms a honeycomb structure.

19. A batt according to any preceding claim wherein the walls of the cells have a metallised lining.

20. A batt according to claim 19, wherein the metallised lining is a metal foil.21 . A batt according to any preceding claim, wherein the metallised lining is a laminate of at least one metal foil and a cellulose layer.

22. A batt according to any preceding claim, wherein the walls of the cellular layer are less than 3mm, preferably less than 2 mm and more preferably less than 1 mm thick.17015683.EAM.EAM23. A batt according to any preceding claim, wherein all of the materials are recyclable.

24. An insulation panel formed of at least one batt according to any of claims 1 to 23 arranged on top of one another.

25. An insulation panel according to claim 24 wherein adjacent batts are separated by spacers.

26. An insulation panel according to claim 24 or claim 25 wherein spacers are formed of a laminated fibrous card structure comprising first and second spaced flat card layers separated by an undulating layer extending between the first and second flat layers.

27. An insulation panel according to any of claims 24 to 26 when dependent on claim any of claims 6 to 8, wherein the moisture proof or resistant film is wrapped around more than one batt.

28. An insulation panel according to any of claims 24 to 27, wherein the batts are arranged with their cellular layers laterally offset from one another.17015683. EAM. EAM

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