EP2941512A1

EP2941512A1 - Rigid insulating panel

Info

Publication number: EP2941512A1
Application number: EP13869579.6A
Authority: EP
Inventors: Dorte Bartnik JOHANSSON; Kristian Skovgaard Jorgensen; Jesper Rene Rasmussen
Original assignee: Rockwool International AS
Current assignee: Rockwool AS
Priority date: 2012-12-31
Filing date: 2013-12-23
Publication date: 2015-11-11
Also published as: WO2014102713A1; EP2941512A4

Abstract

The invention relates to a rigid insulating panel comprising a core plate, and two outer plates disposed at opposite faces of the core plate, wherein: the core plate is formed from polymeric foam composite material comprising a polymeric foam and man-made vitreous fibres produced with a cascade spinner or a spinning cup, wherein at least 50% by weight of the man- made vitreous fibres present in the foam composite material have a length of less than 100 micrometres; and each outer layer comprises man-made vitreous fibres and binder and has a density of at least 300kg/m3, such as at least 450 kg/m3, such as around 500 kg/m3.

Description

RIGID INSULATING PANEL

This invention relates to rigid insulating panels that have a variety of applications in buildings.

Background to the Invention

Rigid insulating panels are used for a variety of different purposes in buildings, where structural integrity and a high level of thermal insulation are important properties. For example, fagade boards need to be effective insulators, but also need high strength in order to deal with the high wind loads that can be exerted on building fagades. Fire resistance is also an important property and it is also desirable to reduce the density of such rigid insulating panels as much as possible to ensure that installation is as simple as possible.

Achieving all of these properties in the same insulating panel is challenging.

Rigid insulating panels can also be used in window and door openings in order to minimise thermal bridging. In such circumstances, rigidity, compressive and bending strength, and resistance to compression are particularly important, because the insulating panel needs to be strong enough to support a window or door frame.

By "resistance to compression", it is meant that a high level of pressure is required to compress a product by a given amount. For a given material, this is related to the "compression modulus of elasticity", which can be measured according to European standard EN 826: 1996.

High density man-made vitreous fibre boards are often used as rigid insulating panels, in particular as fagade boards. They have good insulating properties and excellent fire properties and can be constructed so that they have excellent bending and compressive strength, but it would be desirable to reduce the density of such boards, in order to improve ease of installation. However, decreasing the density of man-made vitreous fibre boards, whilst advantageous in terms of cost and insulating properties, results in a decrease in rigidity and compressive strength, which is unacceptable in insulating elements for use as fagade boards, or which have to support window or door frames. Foam materials are often used where low density and good thermal insulation are desired. However, polymeric foam can have relatively poor fire resistance, making it unsuitable for use in many circumstances. The compressive strength, bending strength and resistance to compression of foam is also generally worse than that of high density mineral fibre boards, which limits the use of foam in circumstances where sufficient strength and rigidity is needed for support of, for example, a window frame or a door frame.

Using foam and high density mineral fibre material together carries the risk of giving rise to a product having inadequate fire resistance and strength, due to the presence of foam, or having a density that is not low enough to provide any practical advantage as compared with high density mineral fibre boards.

Therefore, an object of the invention is to provide a rigid insulating board with good insulating properties, good fire resistance, low density and good bending strength and compressive strength, so that the panels can be used in circumstances where support of another element, such as a door or a window frame, is required.

Summary of the Invention

Therefore, the invention provides a rigid insulating panel comprising a core plate, and two outer plates disposed at opposite faces of the core plate, wherein:

the core plate is formed from polymeric foam composite material comprising a polymeric foam and man-made vitreous fibres produced with a cascade spinner or a spinning cup, wherein at least 50% by weight of the man- made vitreous fibres present in the foam composite material have a length of less than 100 micrometres; and each outer layer comprises man-made vitreous fibres and binder and has a density of at least 300kg/m³, such as at least 450 kg/m³, such as around 500 kg/m³ If a very high strength is needed the density may be up to 1200 kg/m³. The rigid insulating panel of the invention has an excellent combination of properties. The inventors realised that the potential negative impact of polymeric foam on the properties of the insulating panel can be minimised by the use of a specific foam composite material and its positioning in the panel as a plate in between two outer plates, with the outer plates each being formed from high density man-made vitreous fibre material.

The particular foam composite material that is used can include a relatively high level of man-made vitreous fibres, which allows it to have good fire resistance, good compressive strength and resistance to compression. Whilst its fire resistance is not as good as that of a high density man-made vitreous fibre boards, the positioning of the foam composite in the core of the rigid panel ensures that the overall fire properties of the product are good.

Furthermore, whilst the bending strength of the polymeric foam composite is inferior to that of a high density man-made vitreous fibre board, this disadvantage is negated by the positioning of a high density man-made vitreous fibre board on either face of the foam composite plate.

In this way, a reduction in the density of the rigid panel is achieved, together with good fire resistance, high rigidity and strength and good insulating properties.

The rigid insulating panel of the invention has also been found to be particularly suitable for construction of a window mounting collar as described in our earlier application EP 12187703.9. Therefore, the invention also provides a window mounting collar comprising at least one a rigid insulating panel as defined in claim 1. Detailed Description of the Invention

The invention is described in more detail below, with reference to the drawings. Figure 1 shows a rigid insulating panel according to the invention.

Figure 2 is an environmental scanning electron microscope image of a polyurethane foam composite that can be used in the invention

Figure 3 shows a window mounting collar according to the invention.

Figure 4 shows a window mounting system including a window mounting collar formed from rigid insulating panels of the invention.

Figure 1 shows a rigid insulating panel 1 , comprising a core plate 2, and two outer plates 3, 4 disposed at opposite faces of the core plate 2. The panel 1 shown in the drawing is rectangular, but could be cut to any other shape if desired.

The overall density of the rigid insulating panel 1 is generally in the range 250- 800 kg/m³. Typically, the thickness of the rigid insulating panel is from 10mm to 50mm, preferably from 15mm to 40mm, more preferably from 20mm to 35mm. However thicknesses of the rigid insulating panel in the range of 250-400mm or even 500mm is also a possibility, in which case the panel may constitute a wall element for a house.

The rigid insulating panel of the invention can be used, for example, in a window mounting collar, as described below, as a thermally insulating support within a window opening, as a thermally insulating support within a door opening, as a loft hatch, or as a fagade board, or even as a wall element as mentioned above.

Outer Plates

In order that the rigid insulating panel has sufficient bending strength, rigidity and fire resistance, the outer plates 3, 4 each comprise man-made vitreous fibres and binder and each have a density of at least 300 kg/m³. The man-made vitreous fibres in the outer plates can be any suitable fibres such as glass fibres, ceramic fibres or slag fibres, but are preferably stone fibres. In a more preferred embodiment, the outer plates have a density of at least 450 kg/m³ or at least 480 kg/m³, such as around 500 kg/m³. The density of the outer plates may also be substantially higher, such as around 600 kg/m³, or even higher, such as 1200 kg/m³, depending on the circumstances. Preferably, the outer plates have a bending strength of at least 7 N/m²

In a particular embodiment, at least one, preferably both, of the outer plates is produced according to the method set out in International Application PCT/EP201 1/069777. Such plates have a particularly high level of strength.

In order to have good strength, preferably, each outer plate has a thickness of at least 3 mm, more preferably at least 5 mm and most preferably at least 10 mm. However, in order to keep the overall density and weight of the thermal insulating element to a minimum it is preferred that each outer plate has a thickness of less than 30 mm, more preferably less than 20 mm.

The outer plates can be affixed to the insulating layer, for example by use of an adhesive. However, it has been found that it is not necessary to use an adhesive if the outer plates are positioned during formation of the polymeric foam composite material. By avoiding the use of adhesive the rigid insulating panel is particularly well suited for automatic production on a production line. Preferably, there is an intrinsic bond between the outer plates and the core plate and no additional fixing means is present.

Core Plate

The core plate 2 is formed from a polymeric foam composite material as described below. The core plate typically has a thickness of at least 3mm, preferably at least 5 mm and more preferably at least 10 mm. The thickness is usually less than 30 mm, preferably less than 20 mm. In certain constructions the core plate may however be much thicker, such as up to 450mm, e.g. for wall elements. Polymeric Foam Composite Material

The invention makes use of the polymeric foam composite material described in our earlier application filed on 18 August 201 1 and having the application number EP 11 177971.6 and in our international application PCT/EP2012/066196 filed on 20 August 2012. The disclosure of those applications is incorporated herein by reference.

The polymeric foam composite material used in the present invention can be produced from a foamable composition comprising a foam pre-cursor and man- made vitreous fibres, wherein at least 50% by weight of the man-made vitreous fibres have a length of less than 100 micrometres.

The weight percentage of fibres in the polymeric foam composite material or in the foamable composition above or below a given fibre length is measured with a sieving method. A representative sample of the man-made vitreous fibres is placed on a wire mesh screen of a suitable mesh size (the mesh size being the length and width of a square mesh) in a vibrating apparatus. The mesh size can be tested with a scanning electron microscope according to DIN ISO3310. The upper end of the apparatus is sealed with a lid and vibration is carried out until essentially no further fibres fall through the mesh (approximately 30 mins). If the percentage of fibres above and below a number of different lengths needs to be established, it is possible to place several screens with incrementally increasing mesh sizes on top of one another. The fibres remaining on each screen are then weighed.

According to the invention, the man-made vitreous fibres present in the polymeric foam composite must have at least 50% by weight of the fibres with a length less than 100 micrometres as measured by the method above.

By reducing the length of man-made vitreous fibres that are present in the foamable composition and in the polymeric foam composite, a larger quantity of fibres can be included in the foamable composition before an unacceptably high viscosity is reached. As a result, the compressive strength, fire resistance, and in particular the compression modulus of elasticity of the resulting foam can be improved. Previously, it had been thought that ground fibres having such a low length would simply act as a filler, increasing the density of the foam. However, by using mineral fibres with such a high proportion of short fibres, far higher levels of fibres can be incorporated into the foam precursor and the resulting foam. The result of this is that significant increases in the compressive strength and, in particular, the compression modulus of elasticity of the foam can be achieved. Preferably, the length distribution of the man-made vitreous fibres present in the polymeric foam composite or foamable composition is such that at least 50% by weight of the man-made vitreous fibres have a length of less than 75 micrometres, more preferably less than 65 micrometres. Preferably, at least 60% by weight of the man-made vitreous fibres present in the polymeric foam composite or foamable composition have a length less than 100 micrometres, more preferably less than 75 micrometres and most preferably less than 65 micrometres. Generally, the presence of longer man-made vitreous fibres in the polymeric foam composite or foamable composition is found to be a disadvantage in terms of the viscosity of the foamable composition and the ease of mixing. Therefore, it is preferred that at least 80%, or even 85 or 90% of the man-made vitreous fibres present in the polymeric foam composite or foamable composition have a length less than 125 micrometres. Similarly, it is preferred that at least 95%, more preferably at least 97% or 99% by weight of the man-made vitreous fibres present in the polymeric foam composite or foamable composition have a length less than 250 micrometres. The greatest compressive strength can be achieved when at least 90% by weight of the fibres have a length less than 100 micrometers and at least 75% of the fibres by weight have a length less than 65 micrometers. Man-made vitreous fibres having the length distribution discussed above have been found generally to sit within the walls of the cells of the foam composite, without penetrating the cells to a significant extent. Therefore, it is believed that a greater percentage by weight of the fibres in the composite contribute to increasing the strength of the composite rather than merely increasing its density.

It is also preferred that at least some of the fibres present in the foam composite material, for example at least 0.5% or at least 1 % by weight, have a length less than 10 micrometers. These very short fibres are thought to be able to act as nucleating agents in the foam formation process. The action of very short fibres as nucleating agents can favour the production of a foam with numerous small cells rather than fewer large cells.

The fibres present in the polymeric foam composite or in the foamable composition can be any type of man-made vitreous fibres, but are preferably stone fibres. In general, stone fibres have a content by weight of oxides as follows:

Si0₂ 25 to 50%, preferably 38 to 48%

Al₂0₃ 12 to 30%, preferably 15 to 28%

Ti02 up to 2%

Fe₂0₃ 2 to 12%

CaO 5 to 30%, preferably 5 to 18%

MgO up to 15% preferably 1 to 8%

Na₂0 up to 15%

K₂0 up to 15%

P₂0₅ up to 3%

MnO up to 3%

B₂0₃ up to 3%.

These values are all quoted as oxides, with iron expressed as Fe₂0₃, as is conventional. An advantage of using fibres of this composition in the polymeric foam composite material, especially in the context of polyurethane foams, is that the significant level of iron and alumina in the fibres can act as a catalyst in formation of the foam. This effect is particularly relevant when at least some of the iron in the fibres is present as ferric iron, as is usual and/or when the level of Al₂0₃ is particularly high such as 15 to 28% or 18 to 23%.

An alternative stone wool composition useful in the invention, has oxide contents by weight in the following ranges:

Si0₂ 37 to 42%

CaO + MgO 34 to 39%

Fe₂0₃ up to 1 %

Na₂0 + K₂0 up to 3%

Again, the high level of alumina in fibres of this composition can act as a catalyst in the formation of a polyurethane foam. Whilst stone fibres are preferred, the use of glass fibres, slag fibres and ceramic fibres is also possible. The man-made vitreous fibres present in the polymeric foam composite and foamable composition are discontinuous fibres. The term "discontinuous man- made vitreous fibres" is well understood by those skilled in the art. Discontinuous man-made vitreous fibres are, for example, those produced by internal or external centrifugation, for example with a cascade spinner or a spinning cup. Traditionally, fibres produced by these methods have been used for insulation, whilst continuous glass fibres have been used for reinforcement in composites. Continuous fibres (e.g. continuous E glass fibres) are known to be stronger than discontinuous fibres produced by cascade spinning or with a spinning cup (see "Impact of Drawing Stress on the Tensile Strength of Oxide Glass Fibres", J. Am. Ceram. Soc, 93 [10] 3236-3243 (2010)). Nevertheless, it has been found that foam composites comprising short, discontinuous fibres have a compressive strength that is at least comparable with foam composites comprising continuous glass fibres of a similar length. This unexpected level of strength is combined with good fire resistance, a high level of thermal insulation and cost efficient production.

In order to achieve the required length distribution of the fibres, it will usually be necessary for the fibres to be processed further after production with a cascade spinner or a spinning cup. The further processing will usually involve grinding or milling of the fibres for a sufficient time for the required length distribution to be achieved. Usually, the fibres present in the polymeric foam composite and foamable composition have an average diameter of from 2 to 7 micrometres. Preferably, the fibres have an average diameter of from 2 to 6 micrometres, more preferably the fibres have an average diameter of from 3 to 6 micrometres. Thin fibres as preferred in the invention are believed to provide a higher level of thermal insulation to the composite than thicker fibres, but without a significant reduction in strength as compared with thicker fibres as might be expected. The average fibre diameter is determined for a representative sample by measuring the diameter of at least 200 individual fibres by means of the intercept method and scanning electron microscope or optical microscope (1000x magnification).

The foamable composition that can be used to produce the polymeric foam composite comprises a foam precursor and man-made vitreous fibres. The foam precursor is a material that either polymerises (often with another material) to form a polymeric foam or is a polymer that can be expanded with a blowing agent to form a polymeric foam. The composition can be any composition capable of producing a foam on addition of a further component or upon a further processing step being carried out.

Preferred foamable compositions are those capable of producing polyurethane foams. Polyurethane foams are produced by the reaction of the polyol with an isocyanate in the presence of a blowing agent. Therefore, in one embodiment, the foamable composition comprises, in addition to the man-made vitreous fibres, a polyol as the foam precursor. In another embodiment, the foamable composition comprises, in addition to the man-made vitreous fibres, an isocyanate as the foam precursor. In another embodiment, the composition comprises a mixture of an isocyanate and a polyol as the foam precursor.

If the foam precursor is a polyol, then foaming can be induced by adding a further component comprising an isocyanate. If the foam precursor is an isocyanate, foam formation can be induced by the addition of a further component comprising a polyol.

Suitable polyols for use either as the foam precursor or to be added as a further component to the foamable composition to induce foam formation are commercially available polyol mixtures from, for example, Bayer Material Science, BASF or DOW Chemicals. Commercially available polyol compositions are often supplied as a pre-mixed component that comprises polyol and any or all of catalyst(s), flame retardant(s), surfactants and water, the latter which can act as a chemical blowing agent in the foam formation process. Generally it comprises all of these. Such a pre-formed blend of polyol with additives is commonly known as a pre-polyol.

The isocyanate for use either as the foam precursor or to be added as a further component to the foamable composition to induce foam formation is selected on the basis of the density and strength required in the foam composite as well as on the basis of toxicity. It can, for example, be selected from methylene polymethylene polyphenol isocyanates (PMDI), methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI), PMDI or MDI being preferred. One particularly suitable example is diphenylmethane-4, 4' -diisocyanate. Other suitable isocyanates are commercially available from, for example, Bayer Material Science, BASF or DOW Chemicals.

In order to form a foam composite, a blowing agent is required. The blowing agent can be a chemical blowing agent or a physical blowing agent. In some embodiments, the foamable composition comprises a blowing agent. Alternatively, the blowing agent can be added to the foamable composition together with a further component that induces foam formation. In the context of polyurethane foam composites, in a preferred embodiment, the blowing agent is water. Water acts as a chemical blowing agent, reacting with the isocyanate to form C0₂, which acts as the blowing gas.

When the foam-precursor is a polyol, in one embodiment, the foamable composition comprises water as a blowing agent. The water is usually present in such a foamable composition in an amount from 0.3 to 2 % by weight of the foamable composition.

As an alternative, or in addition, a physical blowing agent, such as liquid C0₂ or liquid nitrogen could be included in the foamable composition or added to the foamable composition as part of the further component that induces foam formation.

The foamable composition, in an alternative embodiment, is suitable for forming a phenolic foam. Phenolic foams are formed by a reaction between a phenol and an aldehyde in the presence of an acid or a base. A surfactant and a blowing agent are generally also present to form the foam. Therefore, the foamable composition could comprise, in addition to the man-made vitreous fibres, a phenol and an aldehyde (the foam precursor), a blowing agent and a surfactant. Alternatively, the foamable composition could comprise as the foam precursor, a phenol but no aldehyde, or an aldehyde but no phenol. Whilst foamable compositions suitable for forming polyurethane or phenolic foams are preferred, it is also possible to use foamable compositions suitable for forming polyisocyanurate, expanded polystyrene and extruded polystyrene foams. In an alternative embodiment, the polyurethane foam composite is especially a polyisocyanurate foam composite, where the blowing agent is preferably pentane. Pentane has the advantage over other blowing agents that it is more environmentally friendly and cost effective than for instance HFC blowing agents. Pentane can be c-pentane, i-pentane, or n-pentane or a mixture of two or more of these. The choice between c-pentane, i-pentane and n-pentane is dependent on the production method. They are quite different in boiling point, initial thermal conductivity, aged thermal conductivity and price. The preferred pentane in this invention is n-pentane based on the price and aged thermal conductivity.

The foamable composition that can be used to make the foam composite used in the invention can contain additives in addition to the foam precursor and the man-made vitreous fibres. When it is desired to include additives in the foam composite, as an alternative to including the additives in the foamable composition comprising man-made vitreous fibres, the additive can be included with a further component that is added to the foamable composition to induce foam formation.

As an additive, it is possible for the composition or the foam composite to comprise a fire retardant such as expandable powdered graphite, aluminium trihydrate or magnesium hydroxide. The amount of fire retardant in the composition is preferably from 3 to 20% by weight, more preferably from 5 to 15% by weight and most preferably from 8 to 12 % by weight. The total quantity of fire retardant present in the polymeric foam composite material is preferably from 1 to 10%, more preferably from 2 to 8% and most preferably from 3 to 7 % by weight. Alternatively, or in addition, the foamable composition or foam composite can comprise a flame retardant such as nitrogen- or phosphorus-containing polymers.

The fibres used in the polymeric foam composite can be treated with binder, which, as a result, can be included in the composition and the resulting foam composite as an additive if it is chemically compatible with the composition. The fibres used usually contain less than 10% binder based on the weight of the fibres and binder. The binder is usually present in the foamable composition at a level less than 5% based on the total weight of the foamable composition. The foam composite usually contains less than 5% binder, more usually less than 2.5% binder. In a preferred embodiment, the man-made vitreous fibres used are not treated with binder. In some circumstances, it is advantageous, before mixing the man-made vitreous fibres into the foamable composition, to treat the fibres with a surfactant, usually a cationic surfactant. The surfactant could, alternatively, be added to the composition as a separate component. The presence of a surfactant, in particular a cationic surfactant, in the composition and as a result in the polymeric foam composite material has been found to provide easier mixing and, therefore, a more homogeneous distribution of fibres within the foamable composition and the resulting foam.

One advantage of the described polymeric foam composite is that it is possible to incorporate larger percentages of fibres into the foamable composition, and therefore into the resulting foam, than would be the case with longer fibres. This allows higher levels of fire resistance and compressive strength to be achieved. Preferably, the composition comprises at least 15% by weight, more preferably at least 20% by weight, most preferably at least 35% by weight of man-made vitreous fibres. The polymeric foam composite material itself preferably comprises at least 10% by weight, more preferably at least 15% by weight, most preferably at least 20% by weight of man-made vitreous fibres.

Usually the foamable composition comprises less than 85% by weight, preferably less than 80%, more preferably less than 75% by weight man-made vitreous fibres. The resulting foam composite usually contains less than 80% by weight, preferably less than 60%, more preferably less than 55% by weight man- made vitreous fibres. The polymeric foam composite used in the invention comprises a polymeric foam and man-made vitreous fibres. The foam composite can be formed from the foamable composition as described above. It is preferred that the polymeric foam is a polyurethane foam or a phenolic foam. Polyurethane foams are most preferred due to their low curing time. The first step in the production of the polymeric foam composite material is to form the foamable composition comprising the foam precursor and the mineral fibres. The fibres can be mixed into the foam precursor by a mechanical mixing method such as use of a rotary mixer or simply by stirring. Additives as discussed above can be added to the foamable composition.

Once the fibres and foam precursor have been mixed, the formation of a foam can then be induced. The manner in which the foam is formed depends on the type of foam to be formed and is known to the person skilled in the art for each type of polymeric foam. In this respect, reference is made to "Handbook of Polymeric Foams and Foam Technology" by Klempner et al.

For example, in the case of a polyurethane foam, the man-made vitreous fibres can be mixed with a polyol as the foam precursor. The foamable composition usually also comprises water as a chemical blowing agent. Then foaming can be induced by the addition of an isocyanate.

In the case where a further component is added to the foamable composition to induce foaming, this can be carried out in a high pressure mixing head as commercially available.

In one embodiment, foam formation is induced by the addition of a further component and the further component comprises further man-made vitreous fibres, wherein at least 50% by weight of the further man-made vitreous fibres have a length of less than 100 micrometres. Including man-made vitreous fibres in both the foamable composition and the further component can increase the overall quantity of fibres in the foam composite, by circumventing the practical limitation on the quantity of fibres that can be included in the foamable composition itself.

For example in the context of polyurethane foam composites a foamable composition could comprise a polyol, man-made vitreous fibres and water. Then foaming could be induced by the addition, as the further component, of a mixture of isocyanate and further man-made vitreous fibres, wherein at least 50% of the man-made vitreous fibres have a length of less than 100 micrometers.

In essentially the same process, the mixture of isocyanate and man-made vitreous fibres could constitute the foamable composition, and the mixture of polyol, water and man-made vitreous fibres could constitute the further component.

The quantity of man-made vitreous fibres in the further component is preferably at least 10 % by weight, based on the weight of the further component. More preferably the quantity is at least 20% or at least 30% based on the weight of the further component. Usually, the further component comprises less than 80% by weight, preferably less than 60%, more preferably less than 55% by weight man- made vitreous fibres.

The polymeric foam composite is the material that provides compressive strength and resistance to compression to the thermal insulating element. Therefore, preferably the polymeric foam composite has a compressive strength of at least 1500 kPa and a compression modulus of elasticity of at least 60,000 kPa as measured according to European Standard EN 826:1996.

The following are examples of the polymeric foam composite materials as used in the invention as compared with other polymeric foam composite materials. Example 1 (comparative)

100.0 g of a commercially available composition of diphenylmethane-4,4'- diisocyanate and isomers and homologues of higher functionality, and 100.0 g of a commercially available polyol formulation were mixed by propellers for 20 seconds at 3000 rpm. The material was then placed in a mold to foam, which took about 3 min. The following day, the sample was weighed to determine its density and the compression strength and compression modulus of elasticity were measured according to European Standard EN 826:1996. Compressive strength: 1100 kPa

Compression modulus of elasticity: 32000 kPa

Example 2

100.0 g of the same commercially available polyol formulation as used in Example 1 was mixed with 200.0 g ground stone wool fibres, over 50% of which have a length less than 64 micrometers, for 10 seconds. Then 100.0 g of the commercially available composition of diphenylmethane-4,4' -diisocyanate was added and the mixture was mixed by propellers for 20 seconds at 3000 rpm. The material was then placed in a mold to foam, which took about 3 min. The following day, the sample was weighed to determine its density and the compression strength and compression modulus of elasticity were measured according to European Standard EN 826:1996.

Compressive strength: 1750 kPa

Compression modulus of elasticity: 95000 kPa

Example 3 (comparative)

100.0 g of the same commercially available polyol formulation as used in Examples 1 and 2 was mixed for 10 seconds with 50.0 g stone fibres having a different chemical composition from those used in Example 2 and having an average length of 300 micrometers. 100.0 g of the commercially available composition of diphenylmethane-4,4' -diisocyanate was added. The mixture was then mixed by propellers for 20 seconds at 3000 rpm. The material was placed in a mold to foam, which takes about 3 min. The following day, the sample was weighed to determine its density and the compression strength and compression modulus of elasticity were measured according to European Standard EN 826:1996.

Compressive strength: 934 kPa

Compression modulus of elasticity: 45000 kPa Example 4

Example 3 was repeated, but the fibres were ground such that greater than 50% of the fibres had a length less than 64 micrometers. Following this grinding it became possible to mix 200g of the fibres with the polyol mixture.

Compressive strength: 1785 kPa

Compression modulus of elasticity: 115000 kPa. Example 5

Small flame tests were carried out according to ISO/DIS 1 1925-2 to establish the fire resistance of polymeric foam composites as used in the invention compared with the fire resistance of composites comprising quartz sand rather than fibres according to the invention. The foam used was polyurethane foam. The fibres used had a composition within the following ranges.

Si0₂ 38 to 48wt%

Al₂0₃ 17 to 23wt%

Ti02 up to 2wt%

Fe₂0₃ 2 to 12wt%

Ca0 5 to 18wt%

Mg0 4 to 10wt%

Na₂0 up to 15wt%

K₂0 up to 15wt%

P₂0₅ up to 3wt%

MnO up to 3wt%

B₂0₃ up to 3wt%

The quartz sand used had a particle size up to 2mm. In each composite tested, expanding graphite was included as a fire retardant. The test involved measuring the height of a flame from each composite under controlled conditions. The results were as follows:

Fibre Content Sand Content Graphite Content Flame height (cm) (wt%) (wt%) (wt%)

25 0 8 12-17

25 0 10 7

31 0 10 5

0 25 8 22

0 25 10 1 1

0 31 10 12

Figure 2 is an environmental scanning electron microscope image of a polyurethane foam composite material as used according to the invention, in which the fibres have a length distribution such that 95% by weight of the fibres have a length below 100 micrometers and 75% by weight of the fibres have a length below 63 micrometers. The composite contains 45% fibres by weight of the composite. The instrument used was ESEM, XL 30 TMP (W), FEI/Philips incl. X-ray microanalysis system EDAX. The sample was analysed in low vacuum and mixed mode (BSE/SE).

The image shows the cellular structure of the foam and demonstrates that the man-made vitreous fibres generally sit in the walls of the cells of the foam without penetrating into the cells themselves to a significant extent. Window Mounting Collar

Figure 3 demonstrates the use of rigid insulating panels according to the invention in a window mounting collar as described in our earlier application EP 12187703.9. The window mounting collar is formed from the rigid insulating panels of the invention and has at least one inside face, at least one outside face, a first open end and a second open end.

The mounting collar allows a window to be installed such that it is the window mounting collar that is attached to the building fagade, rather than the window frame itself. This reduces the degree of thermal bridging. Furthermore, window frame can be set away from the plane of the face of the building fagade, so as to reduce further the possibility of thermal bridging and make it possible to install the window mounting collar and new window frame prior to removal of any existing window frame. This means that the window openings can remain sealed during the entire installation process, in particular where external thermal insulation is being installed and a new window frame is being installed so that it is flush with the new external wall insulation.

In Figure 3, a window mounting collar 5 is shown before installation on a building fagade. The mounting collar 5 comprises two side boards 6, an upper cross board 7 and a lower cross board 8, each having an inside face 6a, 7a, 8a and an outside face 6b, 7b, 8b, wherein each side board 6 is joined orthogonally to the upper and lower cross boards 7, 8. The mounting collar has a first open end 9, which, when installed, faces the exterior face of the building fagade. The second open end 10 of the mounting collar 5 receives a window frame, which can be installed either before the mounting collar is affixed to the building fagade or after the mounting collar has been affixed to the building fagade.

The two side boards 6, the upper cross board 7 and the lower cross board 8 are each rigid insulating panels according to the invention, having a core plate, and two outer plates disposed at opposite faces of the core plate.

Attached to the mounting collar 5, on its outside faces 6b, 7b, 8b, are brackets 1 1. In the embodiment shown, the brackets 11 are L-shaped brackets, which are positioned on the outside faces of the mounting collar adjacent to its first open end 9.

Figure 4 shows the mounting collar 5 in place on a building fagade 12, as part of a complete window mounting system. In general, and with reference to Figures 3 and 4, the window mounting system comprises:

a building fagade 12 having an interior face and an exterior face and comprising a window opening; and

a window mounting collar 5 formed from the rigid insulating panels of the invention, the mounting collar having at least one inside face 6a, 7a, 8a, at least one outside face 6b, 7b, 8b, a first open end 9 and a second open end 10. The window mounting collar 5 is affixed to the exterior face of the building fagade 12 so as to surround the window opening and extend outwards from the exterior face of the fagade, such that the first end 9 of the mounting collar is proximal to the building fagade and the second end 10 of the mounting collar is distal from the building fagade. In the embodiment shown, brackets 1 1 affix the mounting collar 5 to the exterior face of the building fagade 12, although alternative fixing means can be used.

The system further comprises a window frame 13 arranged in the mounting collar 5 such that the window frame is separated from the plane of the exterior face of the building fagade 12 by at least 10mm. The separation to be considered is the smallest separation between the inner face of the window frame 13 and the plane of the exterior face of the fagade 12. Where the collar does not extend away from the fagade in a direction perpendicular to the exterior face of the fagade, it is the component of the separation that is perpendicular to the exterior face of the fagade 12 that should be considered.

Preferably, the separation is larger, for example at least 20mm, at least 30mm, at least 50mm, at least 75mm or at least 100mm. When the window frame 12 is mounted in the window mounting collar 5 before the collar is affixed to the exterior face of the building fagade 12, this separation can be ensured by mounting the window frame 13 in the window mounting collar 5 at a distance of at least 10mm, preferably at least 20mm, at least 30mm, at least 50mm, at least 75mm or most preferably at least 100mm from the first end 9 of the mounting collar.

In the particular embodiment shown, the window frame 13 surrounds a window sash 14 and window panes 15. The precise form of the window itself is not crucial, however. External wall insulation 16 (not shown on one side of the mounting collar) can be positioned around the outside of the mounting collar 5 and affixed to the building fagade 12. Usually, as shown, the external wall insulation 16 has the same depth as the mounting collar 5, so the window frame 13 is arranged to be flush with the outer surface of the external wall insulation 16.

Claims

1. A rigid insulating panel comprising a core plate, and two outer plates disposed at opposite faces of the core plate, wherein:

the core plate is formed from polymeric foam composite material comprising a polymeric foam and man-made vitreous fibres produced with a cascade spinner or a spinning cup, wherein at least 50% by weight of the man- made vitreous fibres present in the foam composite material have a length of less than 100 micrometres; and

each outer layer comprises man-made vitreous fibres and binder and has a density of at least 300kg/m³, such as at least 450 kg/m³, such as around 500 kg/m³

2. A panel according to claim 1 , wherein at least 60% by weight of the man- made vitreous fibres present in the polymeric foam composite material have a length less than 65 micrometers.

3. A panel according to any preceding claim, wherein at least 80% by weight of the man-made vitreous fibres present in the polymeric foam composite material have a length less than 125 micrometers.

4. A panel according to any preceding claim, wherein at least 95% by weight of the man-made vitreous fibres present in the polymeric foam composite material have a length less than 250 micrometers.

5. A panel according to any preceding claim, wherein the man-made vitreous fibres present in the foam composite material have an average diameter of from 2 to 6, preferably from 3 to 6 micrometers.

6. A panel according to any preceding claim, wherein the man-made vitreous fibres have a content of oxides as follows:

Si0₂ 25 to 50wt%, preferably 38 to 48wt%

Al₂0₃ 12 to 30wt%, preferably 15 to 28wt%, more preferably 17 to 23wt% Ti0₂ up to 2wt%

Fe₂0₃ 2 to 12wt%

CaO 5 to 30wt%, preferably 5 to 18wt%

MgO up to 15wt%, preferably 4 to 10wt%

Na₂0 up to 15wt%

K₂0 up to 15wt%

P₂0₅ up to 3wt%

MnO up to 3wt%

B₂0₃ up to 3wt%.

7. A panel according to any preceding claim, wherein the polymeric foam is a polyurethane foam.

8. A panel according to any preceding claim, wherein the polymeric foam composite material comprises at least 10% by weight, preferably at least 15% by weight, more preferably at least 20% by weight of man-made vitreous fibres.

9. A panel according to any preceding claim, wherein the polymeric foam composite material comprises less than 80% by weight, preferably less than 60%, more preferably less than 55% by weight of man-made vitreous fibres.

10. A panel according to any preceding claim, wherein the polymeric foam composite further comprises an additive selected from fire retardants, such as expandable powdered graphite, and surfactants, in particular cationic surfactants.

1 1. A panel according to any preceding claim, wherein the outer plates are joined to the core plate without the use of an adhesive.

12. A window mounting collar comprising at least one a rigid insulating panel according to any preceding claim.

13. A window mounting collar according to claim 12, having at least one inside face, at least one outside face, a first open end and a second open end.

14. A window mounting collar according to claim 13, comprising two side boards, an upper cross board and a lower cross board, each having an inside face and an outside face, wherein each side board is joined orthogonally to the upper and lower cross boards and wherein the two side boards, the upper cross board and the lower cross board are each rigid insulating panels according to any of claims 1 to 1 1.