Mineral fibre insulation board

Abstract

 A mineral fibre board having at least two resilient edges in order to prevent any small gaps in the joints between two adjacent boards when these are installed. The purpose of the invention is to improve the effect of the insulation layer and thereby either reducing the heat loss to a minimum in order to comply with new standards for low energy consumption buildings or to improve the fire properties of a fire protection insulation layer on e.g. steel constructions. The invention also concerns a method for producing the mineral fibre board by mechanical compression by rollers.

Description

[0001] The invention concerns a mineral fibre board of relatively high density for heat, sound or fire insulation. The board has at least two resilient minor side surfaces in order to prevent any small gaps in the joints between two adjacent boards. The purpose of the invention is to improve the effect of the insulation layer and thereby either reducing the heat loss to a minimum in order to comply with new standards for low energy consumption buildings or to improve the fire properties of a fire protection insulation layer on e.g. steel constructions. The invention also concerns a method for producing the mineral fibre board and a method for installing the boards.

[0002] It is known to manufacture and use mineral wool insulation boards with at least one resilient edge for e.g. between rafter insulation in buildings. Methods for manufacturing such a board has been described in DE 32 03 622 and in US 5,213,885. The purpose has been to make the insulation adjust easily to differences in the distances between rafters or beams in order to avoid cutting the board into the correct size at the building site. This will save time and reduce the insulation workers exposure to airborne mineral fibres considerably. Mineral wool insulation for this purpose would typically have densities in the range 20 - 35 kg/m³.

[0003] For some purposes e.g. external façade insulation or fire protection of steel constructions, higher densities of the insulation boards are used compared to standard building insulation, e.g. insulation between the rafters. This higher density gives a higher strength and mechanical stability of the insulation board, and it is prevented that the insulation could buckle out from the surface to which it is attached in the area between the fasteners.

[0004] The increased focus on high energy efficient insulation of buildings due to the increased costs for energy and concerns about environmental issues has revealed that it is not enough to increase the thickness and the insulation properties of the insulation layer. It is also necessary to optimise the way the insulation is installed. It is essential for an effective insulation to minimise cold bridges, e.g. the fasteners for the insulation, and to avoid any gaps between the insulation boards. According to ISO 6946 (1997) it is necessary to compensate for possible gaps between the insulation boards by using a thicker insulation layer. This will obviously increase the use of insulation material thereby increasing the costs of the building without gaining a better overall heat insulation.

[0005] Until now there are only two ways to avoid gaps between the insulation boards. The first is to have more than one layer of insulation installed so that the spaces between the boards in the e.g. two layers of boards do not overlap. This method will make the insulation more time consuming to install. The second method is to give the edges of the boards a shape or profile which will prevent an open access to the insulated surface along a straight line perpendicular to the surface against which the insulation is placed. This shape or profile could be groove and tongue like. This method will make each insulation board more expensive to produce, primarily because the production will have a higher waste of mineral wool.

[0006] The present invention has solved the above mentioned problems by making at least two of the minor side surfaces on a high density mineral fibre insulation board resilient, i.e. more elastically compressible than the rest of the board. This has not been done before for mineral fibre insulation densities considerably higher than densities used for standard building insulation, e.g. between rafter insulation below the roof of a building. It has furthermore been found that it is possible to manufacture such boards.

[0007] It has not been obvious to make resilient minor side surfaces in mineral fibre insulation boards for e.g. façade insulation, external roof insulation, fire and heat insulation for marine purposes since it has been essential to have a hard and non-compressible insulation board for these purposes. The specific need for a hard, stable and non-compressible insulation board for a number of purposes has been the main reason for manufacturing these boards at higher densities and thereby higher costs than what would typically be used for insulation inside buildings, e.g. between rafter insulation.

[0008] By resilient minor side surfaces according to the invention minor side surfaces are understood, which are easily compressible by hand, and which are elastically compressible in such a way that removing the compression will make the minor side surface of the board regain substantially its original dimension, however minor deviations from its original dimension should be expected. The rest of the board away from the resilient surfaces has a higher stiffness. The stiffness may be defined according to EN826. Preferably, the whole minor surface should be substantially equally resilient.

[0009] In the manufacturing it is more difficult to make resilient minor side surfaces when the density of the mineral fibre insulation board is increased. A higher force on the rollers compressing the minor side surfaces of the insulation board is needed. This will make it more difficult to let the board or stack of boards pass a station for manufacturing of resilient minor side surfaces. This problem has been solved by the inventive method also claimed. The method is to let one board or a stack of boards pass two zones i.e. two compression stations with rollers on one side of the conveyor and a smooth conveyor surface on the opposite side of the rollers for holding the stack of boards in position. Due to the high density of the boards a high compression force by the rollers is necessary, and therefore the smooth conveyor surface is necessary for securing a well-defined position of the board or stack of boards on the main conveyor band on which the board or stack of boards is moved. The well-defined position of the board or stack of boards is important for obtaining a specific depth of the resilient zone.

[0010] The high compression force by the rollers will often make boards bend. This problem may be solved by letting only one board pass the station at a time and supporting the board on its top major surface while passing the zones (the same zone could be passed more than once). This support could be in the form of a conveyor band covering the majority of the top surface. The support could also be in the form of a smooth surface. This support will prevent the board from bending due to the compression force. Any bending of the board during the compression will mean that the resilient zone will not get the specified depth. Furthermore, bending may cause de-lamination of the board, especially when the board is a dual density board.

[0011] The inventive mineral fibre insulation board will have the advantage that the resilient minor side surfaces will compensate for the tolerances of the boards. These tolerances are often in the millimetre range, and are present in both the width and length of the board and in the angles of the board resulting in deviations from a purely rectangular box shape. The tolerances are due to the fast cutting out the boards from the mineral fibre web moving on the conveyor line. The tolerances will often be in the range up to 5 mm and sometimes even up to 8 mm. This means in practice that there might be difference in the width of a board of 5 mm from one end to the other in the length direction. These tolerances will lead to small gaps between a numbers of the boards on a façade when traditional boards without resilient minor side surfaces are used. The resilient minor side surfaces will make it possible to press the boards together by hand when installing the boards and by compressing the minor side surfaces slightly the elastically compressible zone will fill out any gaps between the boards.

[0012] Due to these tolerances the resilient zone do not need to extend for a distance into the insulation board measured perpendicularly to the minor surface of no more than 50 mm, preferably no more than 30, and even more preferably no more than 20 mm, along the entire length, or the major length, of said minor surface.

[0013] Also when installing insulation boards on a non planar surface the resilient minor side surfaces will help to avoid that two boards which are bended relative to each other (meaning that there is an angle between the planes of the major surfaces of the two boards larger than 0 degrees) will only touch each other along one thin line, resulting in a poor insulation along this line. A non planar surface could be the case when renovating the facades of old buildings.

[0014] There are different methods for fastening the type of insulation boards described by the invention. One possibility is mechanical fixings like steel pins which in the case of external wall insulation may be hammer driven or fastened in drilled holes. In the case of fire insulation of metal constructions the steel pins may be stud welded through the insulation board as described in WO 03/086697. Some kind of head for holding the insulation is placed on the pin before or after fixation of the pin.

[0015] The inventive mineral fibre insulation board will be especially advantages when fasteners placed between two neighbouring boards are applied. It will be easy to push the two boards closely together so that the elastically compressible zone will close any gap around the fastener and thereby avoiding that the fastener may create a small air gap between the two insulation boards, which otherwise often would be the case, because the boards due to the fastener cannot be pushed closely together. The same will be the case when fasteners for the external wall cladding are placed between the insulation boards.

[0016] For several purposes it may be advantageous to make the inventive mineral fibre insulation board from a dual density or triple density mineral fibre product. A dual density insulation board will have two closely connected layers of mineral fibres where the density of the one layer is different from the density of the other. Typically the layer with the highest density will make up the smallest fraction of the total thickness of the insulation board. This would be beneficial in the case of building façade insulation where a higher density of the outer layer of the insulation would make the insulation layer more resistant to mechanical damages during installation of the outer visible surface layer on the facade. If the outer layer is a render layer applied directly to the surface of the mineral fibre insulation layer a high insulation density in the surface will be preferable.

[0017] For especially roof insulation triple density as described in WO0073600 is also relevant for this invention

[0018] For manufacturing a mineral fibre board with elastically compressible minor side surface or edge surfaces it must be realised that mineral fibre insulation comprises a large number of individual fibres having different lengths and diameters. For providing a stable mineral fibre board a binder, e.g. in the form of drops of a thermosetting resin, is added to the mineral fibres. Said binder is cured in a curing oven and will thereafter make the fibres stick to each other at the points where the fibres are in contact with each other. A method for making one or more minor side surface surfaces of this mineral fibre insulation board elastically compressible is to compress one or more rollers a distance into the minor side surface or edge surface. This compression by the roller will break some of the points of binding in the mineral fibre board and thereby make the edge portion of the mineral fibre board softer and more elastically compressible than the rest of the board. The diameter of the compression applying roller(s) must be relatively small in order to concentrate the compression forces in the desired region. The diameter is usually 200 - 500 mm. The rollers are pressed a distance of 15 - 50 mm, preferably 20 - 30 mm into the edge. The numbers of rollers would often be 1 - 7, preferably 2-4.

[0019] For boards of a high density the first roller will be pressed a shorter distance into the board than the following rollers. Usually there will be an increase of the distance by which the roller is pressed into the board from roller to roller, also when several rollers are applied. The distances will be dependent on the density of the board and if it is a dual density or mono density board.

[0020] The strength and the mechanical stability of the mineral fibre board are not only related to the density of the board but also to the binder content. Therefore, the elasticity of the edge portions should be seen in relation to the overall elasticity of the board. The binder content of the board according to the invention is at least 2 %, preferably at least 3 %, and even more preferably at least 4 %.

[0021] The fibre orientation will usually be substantially parallel to the major surfaces of the board when boards of one mono density are applied. If the board is a dual density the fibre orientation will be more complex.

[0022] The invention concerns a mineral fibre insulation board for heat, sound or fire insulation comprising mineral fibres and a binder, said board having two major surfaces being approximately parallel to each other, and having four minor surfaces forming the side surfaces of the insulation board, where at least two of the minor surfaces each represents a surface of a resilient zone of the board covering substantially the surface of the resilient zone which zone goes a distance from the minor surface into the insulation board, where said resilient zone having sufficient elastic properties to prevent substantially any gaps to neighbouring boards when compressed against these during installation and in that the board has a density being sufficiently high to apply the board for purposes such as external wall insulation or fire insulation of steel constructions. By resilient is basically meant that it is easily compressed by hands during installation. The inner portion of the board away from any of the surfaces is substantially stiff and not resilient. The density of the board is more than 60 kg/m³, preferably at least 70 kg/m³, and even more preferably at least 80 kg/m³. The resilient zone along at least two of the edges (i.e. the minor surfaces) has a depth of at least 5 mm, preferably at least 8 mm over the majority of the resilient zone measured from the outer surface of the edge (i.e. the minor surfaces). There may also be a transition zone when going from the resilient zone to the stiff part of the board, where the flexibility is gradually reduced. The resilient zone extending for a distance into the insulation board measured perpendicularly to said minor surface of no more than 50 mm, preferably no more than 30, and even more preferably no more than 20 mm, along the entire length, or the major length, of said minor surface. For a number of purposes the insulation board may comprise at least two different layers of mineral fibre having different densities. This is also known as a dual density board. Preferably, two minor surfaces with a resilient zone have one corner in common, i.e. this is two minor surfaces being perpendicular to each other.

[0023] Furthermore the invention concerns an insulating construction comprising an inner surface against which one layer of insulation boards is installed and fastened by fastening means and an outer covering layer characterised in that the insulation layer comprises one layer of the insulation boards described above. In this construction there will be no gaps between the insulation boards. The insulation boards for this construction may be fastened by mechanical means. The fastening means may be placed along parts of the edges of the insulation boards. The outer covering layer for the construction is usually selected from the group of: metal foil, render, wood, eternit, compressed mineral fibre boards, paint or fleece, e.g. made from glass fibres. Other outer coverings may also be applied An open space where air may circulate between the insulation layer and the outer covering layer is often applied in order to ventilate the construction and remove moisture. The inner surface of this construction is often the façade of a building or the inner surface is a steel construction, e.g. a load carrying steel construction which needs to be fire protected.

[0024] The invention also concerns a method for producing a mineral fibre insulation board for heat, sound or fire insulation comprising mineral fibres and a binder, said board having two major surfaces being approximately parallel to each other, and having four minor surfaces (edges) where at least two minor surfaces (edges) represents a surface of a resilient zone of the board, this resilient zone goes a distance into the board where said mineral fibre insulation having a density of at least 60 kg/m³ and the method comprises the following steps: 1) Mixing mineral fibres and a binder into a web 2) Curing the binder 3) Providing at least two of the four minor surfaces of the board with a resilient zone by a mechanical treatment comprising that the boards passes a zone where rollers compresses the minor surface to make the board more resilient in that zone. Due to the high density often only one board passes the said zone with rollers at a time, and often the board is supported on the majority of its top and bottom surface while passing the zone with rollers. Typically, the rollers will extend different distances into the minor surface in order to gradually compress the minor surface and thereby forming a more homogenous resilient zone.

[0025] Finally, the invention concerns a method of installing mineral fibre insulation for heat, sound or fire insulation where the boards have at least two resilient edges and said boards have a density of at least 60 kg/m³ and in that any gaps between the boards are avoided by pressing the boards together so that said resilient edges are compressed by hand and therefore closes any gaps between two boards and in that only one layer of insulation boards are installed on the surface.

[0026] In a first embodiment of the invention the mineral fibre insulation board is made for being applied for heat insulation of building facades. The density of the board is approximately 60 kg/m³, preferably more than 60 kg/m³, and even more preferably more than 70 kg/m³. The board has a length of 400 - 1000 mm, preferably 500 - 700 mm and even more preferably approximately 600 mm. The board has a height of 600 - 2000 mm, preferably 800 - 1500 mm and even more preferably 1000 - 1200 mm. The board has a thickness of 100 - 400 mm, preferably 150 - 300 mm and even more preferably approximately 200 mm. The board has two edges which are made resilient into a depth of 5 - 15 mm, preferably 8 - 13 mm and even more preferably 10 - 12 mm. These two resilient edges have one corner in common.

[0027] In a further embodiment of the invention a dual density mineral fibre insulation board is used. This board will have an average density and all dimensions as described in the previous embodiment. But this board will have a top layer where the density is higher than in the lower layer of the board. The top layer would typically have a thickness of 8 - 20 mm, preferably 10 - 15 mm. The density of the top layer will be a factor of 1.5 - 3, preferably a factor of 2 higher than the density of the lower layer.

[0028] In a further embodiment of the invention the mineral fibre insulation board is made for being applied for fire insulation of metal constructions, e.g. steel or aluminium constructions, such as the load-bearing steel constructions in buildings or ship bulkheads and decks on ships e.g. on the lower side of decks, including the girders.

[0029] With the existing products without resilient edges it is necessary to cut the bats into the exact size in order to avoid small gaps between the bats. This will take longer time and, in the case of a fire differences in the thermal expansions of the materials may form small gaps between the bats. Also sintering of the mineral fibre insulation material may cause small gaps. Such gaps will reduce the time it takes the heat and eventually the fire on a ship to spread from one deck to another or in a building the time it takes the load bearing steel construction to reach a temperature where it looses its mechanical strength.

[0030] A fire insulation board according to the invention will have at least two resilient edges giving an elastically compressible zone along a region of the edge, which due to its elasticity will regain its original shape after compression. The compression of this zone means that the risk of gaps occurring during a fire is considerably reduced.

[0031] When applying the idea of one or more resilient edges for fire insulation on metal constructions, the mineral wool would typically have a higher density compared to heat insulation in a building. The density of the mineral wool board according to this embodiment would typically be in the range of more than 60 to 150 kg/m³, preferably in the range of 70 to 140 kg/m³, and even more preferably in the range of 80 to 130 kg/m³.

[0032] A preferred embodiment for manufacturing the mineral fibre insulation board according to the invention is to let a stack of 4 - 8 boards pass a first zone with 2 - 4 rollers on one side of the conveyor and a smooth conveyor surface on the opposite side of the rollers for holding the stack of boards in position. This is necessary due to the high density of the boards. The distance between the rollers and the opposite smooth surface must be adjusted so that the rollers will compress the edges of the boards the necessary distance, e.g. 20 mm giving a resilient depth of the surface of approximately 10 - 12 mm. As the two resilient edges on the inventive insulation board preferably should have a common corner to facilitate easy installation, the stack of boards is turned 90 degrees after the first compression. Then the stack will pass a second zone with 2 ― 4 rollers on one side of the conveyor and a smooth conveyor surface on the opposite side of the rollers. A third and a fourth zone could also be applied if more than two resilient edges on the boards are needed. Instead of the 2 ― 4 different zones, the stack of boards could pass the same zone more than one time after being rotated. This would reduce the necessary equipment on the factory line.

[0033] Another preferred embodiment for manufacturing the mineral fibre insulation board according to the invention is to let one board pass a first zone with 2 - 4 rollers on one side of the conveyor and a smooth conveyor surface on the opposite side of the rollers. Then the board is turned 90 degrees and following this the board will pass a second zone with 2 - 4 rollers on one side of the conveyor and a smooth conveyor surface on the opposite side of the rollers. While passing the first zone and the second zone the board is being supported on its top major surface. This support could be in the form of a conveyor band covering the majority of the top surface preventing the board from bending due to the compression force. Also in this embodiment the more than two zones may be needed, and the board could pass the same zone more than one time.

[0034] In the following the invention is described further with reference to the figures.

Figure 1

An insulation board with two resilient edges marked.

Figure 2

Four boards without resilient edges mounted on a facade

Figure 3

Four boards without resilient edges mounted on a non-planar facade

Figure 4

Four boards with resilient edges mounted on a facade

Figure 5

A stack of boards passing a compression station seen from top.

Figure 6

A stack of boards passing a compression station seen from the side.

[0035] The mineral fibre insulation board 1 in figure 1 has two resilient edges 2 meeting in the upper left corner 3. This makes it possible to install the insulation in an easy way so that all connections between boards can be made involving at least one resilient edge.

[0036] Figure 2 illustrates the result of installing boards 1 without resilient edges. Due to the inaccuracy of cutting out the boards different gaps between the installed boards will occur. If the edge are not strictly perpendicular to the major surfaces, a V-shaped gap 4 may be the result. The open side of the V may be on both sides of the insulation 4, 5. If the board shape deviates from a rectangular box shape several open gaps may occur between the boards 6.

[0037] Figure 3 illustrates the result of installing boards 1 without resilient edges when the wall surface is non planar. V-shaped gaps 7 will be the result even if the shape of the boards is perfect.

[0038] Figure 4 illustrates equivalent situations as in figure 2 and 3, but with use of the new board with resilient edges. In this case there are no gaps between the boards.

[0039] Figure 5 shows the compression station from above and figure 6 shows it from a side view. The stack of boards 22, which also could be one single board 1, is moved on the conveyor (not shown) along the factory line. The rollers 20 will compress one edge slightly in a local zone. The opposite conveyor 21 formed by a moving band 23 and at least two rollers 24, keeps the stack of boards 22 in the right position. The first roller 20 which is being passed will often extend a shorter distance into the stack of boards 22 than the following rollers 20' and 20". It is important that the whole minor surface is compressed in this process.

[0040] In an example of the invention the mineral fibre insulation board is made for being applied for heat insulation of building facades. The density of the board is approximately 60 kg/m³, preferably more than 60 kg/m³, it has a length of 600 mm a height of 1000 mm and a thickness of 200 mm. The board has two edges which are made resilient into a depth 10 ― 12 mm. These two resilient edges have one corner in common.

Claims

1. A mineral fibre insulation board comprising mineral fibres and a binder, said board having two major surfaces being approximately parallel to each other and four minor surfaces forming the side surfaces of the insulation board, where at least two of the minor surfaces each represents a surface of a zone of the board being resilient to a greater extent than the remaining part of the board and extending a distance into the insulation board, characterised in said zone being resilient to such an extent as to prevent substantially any gaps to neighbouring boards when compressed against these during installation and in said board having a density of more than 60 kg/m³, preferably at least 70 kg/m³, and even more preferably at least 80 kg/m³.

2. A mineral fibre insulation board according to claim 1, said greater resiliency being such that the zone is compressible by hand.

3. A mineral fibre insulation board according to claim 1 or 2, characterised in that said zone extending for a distance into the insulation board measured perpendicularly to said minor surface of at least 5 mm, preferably at least 8 mm.

4. A mineral fibre insulation board according to claim 1, 2 or 3, characterised in that said zone extending for a distance into the insulation board measured perpendicularly to said minor surface of no more than 50 mm, preferably no more than 30, and even more preferably no more than 20 mm, along the entire length, or the major length, of said minor surface.

5. A mineral fibre insulation board according to claim 1, 2, 3 or 4 characterised in that the insulation board comprises at least two layers of mineral fibre insulation having different densities and extending parallel with said major surface.

6. A mineral fibre insulation board according to claim 1, 2, 3, 4 or 5 characterised in that only two minor surfaces are provided with said zone said two surfaces having one corner in common, e.g. they are perpendicular to each other.

7. An insulating construction comprising an inner surface against which one layer of insulation boards is installed and fastened by fastening means and an outer covering layer characterised in that the insulation layer comprises one layer of insulation boards according to any of the claims 1 - 6.

8. An insulating construction according to claim 7 characterised in that the insulation boards are fastened by mechanical means.

9. An insulating construction according to claim 8 characterised in that the fastening means is placed along parts of the edges of the insulation boards.

10. An insulating construction according to any of claims 7- 9 characterised in that the outer covering layer is selected from the group of: metal foil, render, wood, eternit, compressed mineral fibre boards, paint or fleece

11. An insulating construction according to any of the claims 7 - 10 characterised in that there is an open space where air may circulate between the insulation layer and the outer covering layer.

12. An insulating construction according to any of the claims 7-11 characterised in that the inner surface is the façade of a building.

13. An insulating construction according to any of the claims 7- 11 characterised in that the inner surface is a steel construction, e.g. a load carrying steel construction which needs to be fire protected.

14. A method for producing a mineral fibre insulation board for heat, sound or fire insulation comprising mineral fibres and a binder, said board having two major surfaces being approximately parallel to each other, and having four minor surfaces where at least two minor surfaces represents a surface of a resilient zone of the board characterised in that said mineral fibre insulation having a density of at least 60 kg/m³ and the method comprises the following steps

- mixing mineral fibres and a binder into a web

- curing the binder

- providing at least two of the four minor surfaces of the board with a resilient zone by a mechanical treatment comprising that the boards passes a zone where rollers compresses the minor surface to make the board more resilient in that zone.

15. Method according to Claim 13 characterised in that only one board passes the said zone with rollers at a time.

16. Method according to Claim 13 or 14 characterised in that the board is supported on the majority of its top surface while passing the zone with rollers.

17. Method according to Claim 13, 14 or 15 characterised in that more than one roller is applied and in that the rollers extend different distances into the minor surface of the board e.g. so that the first roller 20 extend a shorter distance into the board than the following roller 20'.

18. Method of installing mineral fibre insulation for heat, sound or fire insulation where the boards have at least two resilient edges and characterised in that said boards have a density of at least 60 kg/m³ and in that any gaps between the boards are avoided by pressing the boards together so that said resilient edges are compressed by hand and therefore closes any gaps between two boards and in that only one layer of insulation boards are installed on the surface.

Drawing