Mineral wool product with a coating layer

Abstract

The present invention relates to a mineral wool product comprising a first mineral wool substrate comprising mineral fibers and having a first major surface and an opposed second major surface; and a coating layer, formed directly on at least one of the first major surface or the second major surface by application and curing of a coating mixture. The coating mixture comprises (i) a particulate precursor material comprising aluminum and silicon and at least a first precursor selected from ground mineral wool, ground mineral fibers, metakaolin, slag, fly ash, silica-based minerals, or any mixtures thereof; and (ii) about 10 wt.% to about 70 wt.% of an activator, calculated from the total weight of the applied coating mixture. The invention relates also to the use of the coating mixture for manufacturing of a mineral wool product.

Description

[0001] MINERAL WOOL PRODUCT WITH A COATING LAYER

[0002] FIELD

[0003]

[0001] The present invention relates to a mineral wool product with a coating layer and to a use of a coating mixture according to the preambles of the enclosed independent claims.

[0004] BACKGROUND

[0005]

[0002] Mineral wool products are well known and have been used extensively in the building industry for insulation, both thermal and acoustic, and for fire protection. The mineral wool products are commonly provided in the form of batts or boards.

[0006]

[0003] Mineral wool products generally comprise man-made vitreous fibers (MMVF), i.e. mineral fibers, which are bound together by a polymeric binder composition. Mineral wool products comprise, for example, different types of slag wool, rock wool, stone wool, and the like. A general process of making mineral wool products includes preparing a molten mineral melt, fiberizing the mineral melt via internal or external centrifugation to form a plurality of mineral wool fibers, attenuating the mineral wool fibers with a gas stream, and collecting the mineral wool fibers in the form of a web. A binder or sizing composition is typically applied to the mineral wool fibers when entrained in the gas stream, or onto the web. The collected fiber web may be consolidated by cross-lapping or by other consolidation methods. The fiber web is then cured, for example by passing the consolidated fiber web through a curing oven. The cured fiber web may be cut into mineral wool products of desired sizes and dimensions.

[0007]

[0004] A certain amount of mineral wool / mineral fiber waste is generated in the manufacturing process of mineral wool products in form of rejected products and / or excess fiber material generated during product shaping and / or cutting. Mineral wool waste is generated also during installation and at the end of a mineral wool product’s life cycle, when the mineral wool products are uninstalled during demolition of building constructions. The growing awareness of sustainability and circular economy has increased the need and interest of collecting the waste formed during installation as well as at the end of the product’s life cycle. Simultaneously, there is a growing need to find further uses for the formed and / or collected mineral wool and mineral fiber waste.

[0005] Mineral wool fibers are intrinsically non-combustible, but the binder compositions used therewith are organic and, in particular applications, such as fire doors, it would be desirable to improve the fire resistance of mineral wool products. There have been attempts to improve the fire resistance of mineral wool products, for example, by applying on the mineral wool products a layer of organic intumescent paint. However, such paints may react prematurely to fire and create excessive heat and smoke. Such paints may also melt when exposed to heat and create a sticky material. Organic intumescent paints may also contain compounds and substances that create an occupational hazard during application of the paint and may require additional protection.

[0008]

[0006] For some applications two mineral wool slabs or batts are adhered together or a facing is adhered on the surface of the mineral wool slabs or batts. The adhesives used do not always have the same fire-resistance properties as the mineral wool product itself. Thus, the used adhesive may lower the fire resistance of otherwise non-combustible mineral wool product.

[0009]

[0007] Consequently, there is a need not only to reuse or recycle the mineral wool waste, but also to develop mineral wool products with good, or even improved, fire resistance properties.

[0010] SUMMARY

[0011]

[0008] An object of the present invention is to minimize or even totally eliminate the disadvantages existing in the prior art.

[0012]

[0009] Another object of the present invention is to provide a mineral wool product with good, or even improved, fire resistance properties.

[0013]

[0010] Yet another object of the present invention is to provide a new way of adhering two mineral wool substrates together or adhering a facing to a mineral wool substrate.

[0014]

[0011] The invention is defined in the characterizing parts of the enclosed independent claims. Some preferable embodiments of the invention are defined in the dependent claims. All described features apply to all aspects of the invention, both the product and use, whenever applicable, even if it is not necessarily always stated so.

[0015]

[0012] A typical mineral wool product according to the present invention comprises:

[0016] - a first mineral wool substrate comprising mineral fibers and having a first major surface and an opposed second major surface; and

[0017] - a coating layer, formed directly on at least one of the first major surface or the second major surface by application and curing of a coating mixture comprising:

[0018] (i) a particulate precursor material comprising aluminum and silicon and at least a first precursor selected from ground mineral wool, ground mineral fibers, metakaolin, slag, fly ash, silica-based minerals, or any mixtures thereof; and

[0019] (ii) about 10 wt.% to about 70 wt.% of an activator, calculated from the total weight of the applied coating mixture.

[0020]

[0013] Typical use of a coating mixture according to the present invention is for manufacturing of a mineral wool product comprising a first mineral wool substrate comprising mineral fibers, the coating mixture comprising:

[0021] (i) a particulate precursor material comprising aluminum and silica and at least a first precursor selected from ground mineral fibers, metakaolin, slag, fly ash, silica-based minerals, or any mixtures thereof; and

[0022] (ii) about 10 wt.% to about 70 wt.% of an activator, calculated from the total weight of the applied coating mixture

[0023]

[0014] The general inventive concepts are based on the development of a novel fire-resistant coating layer for mineral wool products, for providing exceptional fire resistance and / or bonding properties for adhesion of facings or the like. The coating layer is formed from a cured coating mixture comprising a particulate precursor material comprising a first precursor comprising aluminum and / or silicon, wherein the at least first precursor is selected from ground mineral wool, ground mineral fibers, metakaolin, slag, fly ash, silica-based minerals, or any mixtures thereof. The coating mixture further comprises about 10 wt.% to about 70 wt.% of an activator, calculated from the total weight of the applied coating mixture.

[0015] Other aspects and features of the general inventive concepts will become more readily apparent to those of ordinary skill in the art upon review of the following description and the various exemplary embodiments, in conjunction with the accompanying figures.

[0024] BRIEF DESCRIPTION OF THE DRAWINGS

[0025]

[0016] The general inventive concepts, as well as some embodiments and advantages thereof, are described below in greater detail, schematically and by way of example, with reference to the drawings in which:

[0026]

[0017] FIG. 1 graphically illustrates a fire curve representing the time delay for each mineral wool product sample to reach a particular temperature.

[0027]

[0018] FIG. 2 graphically illustrates a fire curve representing the time delay for each mineral wool product sample to reach a particular temperature.

[0028]

[0019] FIG. 3 graphically illustrates the results of adhesion testing for mineral wool slabs produced and faced with both a glass fiber mat (GM) and a spun-bond polyethylene fiber facer (PE).

[0029] DETAILED DESCRIPTION

[0030]

[0020] Now it has been found that a coating layer can be directly formed on a mineral wool substrate by application and curing of a coating mixture comprising a particulate precursor material and an activator. The coating layer can be formed in a straightforward manner by using conventional coating techniques. The chemical reactions needed for obtaining the final coating layer can take place on the surface of the mineral wool substrate and the applied coating mixture remains on the surface of the mineral wool substrate and is attached to it with an appropriate strength. The present invention does not require any complicated formation of a separate coating layer that is attached to the substrate after its formation. The direct forming of the coating layer is advantageous, as it reduces the risks of coating layer damage and the preparation steps needed. Furthermore, the direct forming of the coating layer on the surface of the mineral wool substrate is advantageous when substrates with irregular surface structure are coated. The formed coating layer has advantageous fire protection properties, as it has a low content of organic components, if any at all. The formed coating layer may be even free of organic components. The present invention is thus able to achieve improved fire protection for the mineral wool product comprising or consisting of a mineral wool substrate coated with the coating layer.

[0021] The coating mixture for the coating layer comprises a particulate precursor material and an activator. The particulate precursor material comprises at least aluminum and silica. Presence of these elements enable the formation of inorganic alumino-silicate noncrystalline polymer network in the coating layer when the precursor material is activated in the presence of the activator and water. The formed coating layer thus comprises geopolymer or geopolymer-like material. It is assumed that the inorganic alumino-silicate non-crystalline polymer network is formed from particulate precursor material, when it is dissolved, or at least partially dissolved in the presence of the activator and the inorganic polymerization is initiated.

[0031]

[0022] The particulate precursor material comprises at least a first precursor, which comprises aluminum and / or silicon. If the first precursor(s) comprise(s) aluminum and silicon, the particulate precursor material may consist solely of the first precursor(s). If the first precursor comprises aluminum or silicon, then the particulate precursor material comprises further components, for example, co-precursors that provide the presence of both aluminum and silicon in the particulate precursor material.

[0032]

[0023] The first precursor is selected from ground mineral wool, ground mineral fibers, metakaolin, slag, fly ash, silica-based minerals, or any mixtures thereof. Silica-based minerals may be, for example, microsilica, fumed silica or any of their mixtures. Preferably, the particulate precursor material comprises or consists of waste-based and / or recycled first precursor, such as ground mineral fibers, ground mineral wool, slag, fly ash or any mixtures thereof. This means that the coating layer may be formed totally or at least partly from the said recycled and / or waste material. According to one preferable embodiment, the particulate precursor material comprises or consists of waste and / or recycled mineral wool and / or mineral fibers. In the present context waste or recycled mineral wool or waste or recycled mineral fibers encompass any of waste or recycled mineral wool or mineral fibers, such as rock wool, stone wool, slag wool, glass fibers, ceramic fibers, and the corresponding mineral fibers, preferably rock wool, stone wool, slag wool. In general, utilizing waste-based material as the particulate precursor material, such as waste mineral wool or fly ash, diverts waste away from landfills and provides access to sustainable and non-conventional raw materials for the construction industry in the future.

[0024] According to one preferable embodiment, the particulate precursor comprises a first precursor, which comprises or consists of ground mineral wool and / or ground mineral fibers. The ground mineral wool and ground mineral fibers preferably comprise both aluminum oxide and silicon dioxide, which makes them especially suitable as particulate precursor material. For example, the ground mineral wool or the ground mineral fibers may preferably comprise 35 - 53 weight-%, preferably 37 - 52 weight-%, of SiCh, and / or 12 - 27 weight- %, preferably 13 - 25 weight-%, of AI2O3, calculated from total weight of inorganic oxides present in the mineral wool / mineral fibers. Alternatively, the ground mineral wool or the ground mineral fibers may be ground mineral wool or the ground mineral fibers may be ground glass wool or ground glass fibers and comprise 50 - 75 weight-%, preferably 53 - 60 weight-%, of SiCh, and / or 0.5 - 16 weight-%, preferably 2 - 10 weight-%, of AI2O3, calculated from total weight of inorganic oxides present in the mineral wool / mineral fibers.

[0033]

[0025] The mineral wool and / or mineral fibers are ground or milled by using any suitable milling or grinding device to form the first precursor. In case the mineral wool or the mineral fibers comprises organic material, such as a binder or sizing composition, the grinding or milling process may include a removal step for removing or limiting the amount of organic material present in the ground mineral wool or fibers, used as the first precursor. For example, the ground mineral wool or ground mineral fibers preferably include less than 10 wt.% of organic material, including no greater than 8 wt.%, no greater than 6 wt.%, no greater than 5.5 wt.%, no greater than 5 wt.%, no greater than 3 wt.%, or no greater than 1 wt.% of organic material, based on the total weight of the first precursor. Furthermore, if the mineral wool, which is ground and used as first precursor, is obtained as a waste, e.g., construction and / or demolition waste, the mineral wool can undergo further separation process(es), before or after grinding, to remove any unwanted components from the waste mineral wool which is used as the first precursor.

[0034]

[0026] The particulate precursor material, especially the first precursor in the particulate precursor material, may have, for example, an average particle size D90 <250 pm, preferably <200 pm. The average particle size D90 for the particulate precursor material and for the first precursor may be 20 - 250 pm, preferably 30 - 200 pm.

[0027] The coating mixture further comprises an activator. The activator may be in form of a particulate solid material, an aqueous slurry or an aqueous solution. The particulate precursor material is mixed with the activator in order to initiate the desired reaction for formation of the inorganic alumino-silicate non-crystalline polymer network. The activator is preferably in form of slurry or solution, dissolving the particulate precursor material. Alternatively, water can be added to the coating mixture for dissolving the particulate precursor material and activating the activator. The activator may be an alkali-activator or an acid activator. The activator preferably has enough basic or acidic groups to initiate sufficient polymerization reaction within the coating mixture to provide coating layer with appropriate strength. The alkali-activator may be selected from one or more of alkali hydroxides, alkali silicates, alkali aluminates, alkali sulfates, alkali carbonates or any mixtures thereof. Preferably the alkali-activator may be selected from one or more of alkali hydroxides, alkali silicates, alkali aluminates, alkali sulfates, or any mixtures thereof. Exemplary alkali hydroxide activators include sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, and mixtures thereof. Exemplary alkali silicate activators include sodium silicate, water glass, and any mixtures thereof. Exemplary aluminate activators include sodium aluminate. The acid-activator may be selected from phosphonic acid, phosphoric acid, carboxylic acid, and any mixture thereof.

[0035]

[0028] According to one embodiment the coating mixture may have a solid content of 20 - 85 wt.%, for example 25 - 75 wt.% or 30 - 50 wt.%. This means that the coating mixture may contain 15 - 80 wt.% of water, for example 25 - 75 wt.% or 50 - 80 wt.% of water. The solid content of the coating mixture is suitable for application with various different application methods and devices. For example, the coating mixture can be distributed or applied on the surface of mineral wool substrate by spraying or coating.

[0036]

[0029] Preferably the coating mixture is free of other solvents than water.

[0037]

[0030] The coating mixture may be applied to the mineral wool product in a foamed or nonfoamed form.

[0038]

[0031] According to one embodiment the coating mixture may comprise (i) 30 - 90 wt.%, preferably 35 - 85 wt.%, more preferably 45 - 80 wt.% or 50 - 75 wt.% or 55 - 70 wt.%, of the precursor material, and (ii) 10 - 70 wt.%, preferably 15 - 65 wt.%, more preferably 20 - 55 wt.% or 25 - 50 wt.% or 30 - 45 wt.%, of the activator, calculated from the total weight of the applied coating mixture. This kind of a coating mixture provides a non-foamed coating layer or a dense coating. The non-foamed coating layer is effective as an adhesive between the mineral wool substrate and a facing or as an adhesive between two mineral wool substrates. The non-foamed coating is suitable also for providing a fire-resistant or protective coating layer on the surface of the substrate. The density of a non-foamed coating may be 1200 - 2200 kg / m3, preferably 1500 - 2000 kg / m3or 1600 - 1900 kg / m3.

[0039]

[0032] According to one embodiment, the coating layer may be a foamed layer, comprising closed gas-filled pores, wherein the coating mixture comprises a foaming agent. The gas phase in the closed gas filled pores may comprise from 10 to 80 volume-%, preferably from 15 to 70 volume-%, of the total coating layer volume (the rest is the solids of the coating layer). The foamed layer is obtained by foaming the coating mixture, applying the foamed coating mixture directly on the mineral wool substrate and curing the coating mixture. Alternatively, the foaming may be achieved after the application of the coating mixture directly on the mineral wool substrate. The gas-filled pores of the coating layer contain gas which have been present during the foaming, such as air or hydrogen. The foaming agent can be at least one surfactant composition, an aluminum powder or any of their mixtures. The used surfactant composition may comprise one or more surfactants and optionally water. The foaming agent, such as surfactant, may change the surface tension properties of the coating mixture so that gas bubbles, formed during mixing or agitation of the foaming agent into the coating mixture, are trapped within the coating layer during application and curing of the coating layer. Alternatively, or in addition, the coating mixture may comprise a foaming agent, such as aluminum powder, which can react with the other components of the coating mixture, such as water, under formation of gas, which becomes trapped within the coating layer during application and curing of the coating layer.

[0040]

[0033] When the coating layer is a foamed layer, the coating mixture may comprises (i) 30 - 90 wt.%, preferably 35 - 85 wt.%, more preferably 45 - 80 wt.% or 50 - 75 wt.% or 55 - 73 wt.%, of the precursor material, and (ii) 10 - 70 wt.%, preferably 15 - 65 wt.%, more preferably 20 - 55 wt.% or 25 - 50 wt.% or 27 - 45 wt.%, of the activator, wherein amounts of (i) the precursor material and (ii) the activator are calculated from the total weight of the coating mixture. The coating mixture further comprises 0.05 - 50 wt.%, preferably 0.1 - 40 wt.%, more preferably 0.2 - 30 wt.% or 0.5 - 20 wt.%, of the foaming agent, based on total weight of (i) the precursor material and (ii) the activator. The amount of the foaming agent may be selected on basis of the foaming agent used and / or the foaming degree desired. For example, lower amounts of foaming agent are needed when aluminum powder is used as the foaming agent.

[0041]

[0034] According to one preferable embodiment of the coating mixture is free of foaming agent.

[0042]

[0035] The particulate precursor material of the coating mixture may further comprise at least one co-precursor, which is different from the first precursor. The first precursor may be mixed or blended with one or more co-precursors comprising additional raw materials to obtain a desired chemical composition for the particulate precursor material, to tailor the properties of the coating mixture and obtain the desired coating layer. The co-precursor(s) may be used especially to adjust the amount of the elements aluminum and / or silicon in the particulate precursor material. Preferably the co-precursor may be selected from calcium- based minerals, such as gypsum, kaolinite, calcinated clay, or any of their mixtures; phosphate-based minerals; or any mixtures thereof.

[0043]

[0036] When the first precursor comprises or consists of ground mineral wool, ground mineral fibers or their mixtures, the particulate precursor material may comprise 0.5 - 100 wt.%, preferably 0.5 - 99.9 wt.%, of the first precursor, and between 0 - 99.5 wt.%, preferably 0.1 - 99.5 wt.%, of one or more co-precursors. According to one embodiment the particulate precursor material may comprise 5 - 85 wt.%, preferably 10 - 75 wt.% or 15 - 65 wt.% or 20 - 50 wt.%, of the first precursor, and 15 - 95 wt.%, preferably 25 - 90 wt.% or 35 - 85 wt.% or 50 - 80 wt.%, of one or more co-precursors, including all endpoints, subranges, and combinations therebetween.

[0044]

[0037] The coating mixture may further comprise one or more additives selected from curing accelerators, colorants, hydrophobing agents, anti-cracking agents, intumescent agents, processing aids, surfactants, rheology modifiers, pH adjusters, reinforcement materials, and UV stabilizers. Curing accelerators may be selected from calcium-containing compounds, such as calcium hydroxide. Colorants may be selected from inorganic pigments, for example titanium dioxide (white), iron oxide (red), chromium oxide (green). Use of colorants makes it possible to provide visually attractive and distinguishable coating layers. Hydrophobing agents may include silicone. Anti-cracking agents may include glycerol. Intumescent agents may include expendable graphite.

[0045]

[0038] The coating mixture is applied as foamed or non-foamed directly to at least one major surface of a first mineral wool substrate, such as a slab or batt. The direct application means that the coating mixture comes into direct contact with the surface of the mineral wool substrate at the time of the application and that the final coating layer is cured and formed on the surface of the mineral wool substrate. The coating mixture can be applied to one or both major surfaces of the mineral wool substrate using any one of a variety of coating methods. The coating layer may be formed directly on the major surface of the substrate by applying the coating mixture by a roller, by brushing, spraying, dipping, or by spin coating, flow coating, by curtain coating or by mechanical vibration-assisted coating. Other coating methods known and used in the art may be employed and are contemplated within the subject disclosure.

[0046]

[0039] After application of the coating mixture on the mineral wool substrate, the formed coating layer is subjected to curing, for example, sent through a curing oven with an elevated temperature, or cured at room temperature. Curing ensures the formation of the desired inorganic alumino-silicate non-crystalline polymer network. The curing may be performed by using any conventional curing method. According to one preferable embodiment, after application of the coating mixture directly on the major surface of the mineral wool substrate, the obtained coated mineral wool product may be subjected to curing in an oven. The temperature of the curing oven may be in a range of 30 - 60 °C, preferably from 35 - 50 °C or 35 - 45 °C. The curing time may be 1 - 48 hours, typically from 6 hours to about 24 hours. The result is a hardened coating layer with fire-resistant properties on at least one the major surface of the mineral wool product.

[0047]

[0040] The cured coating layer may have a layer weight in a range of 0.2 - 100 kg / m2, preferably 0.5 - 80 kg / m2, more preferably 0.8 - 65 kg / m2or 1 - 50 kg / m2or 1.75 - 40 kg / m2, including all endpoints and subranges therebetween. The weight of the coating layer may be freely selected depending on the intended end-use of the mineral wool product.

[0048]

[0041] The cured coating layer may have a thickness of no greater than 10 mm, preferably no greater than 5 mm. For example, the cured coating layer may have the thickness in a range of 0.1 - 10 mm, preferably 0.1 - 8 mm, more preferably 0.25 - 6 mm or 0.2 - 4.5 mm. The thickness of the cured coating layer may be, for example, 0.75 - 5 mm, preferably 1 - 4 mm, including all endpoints and subranges therebetween. The direct forming of the coating layer on the surface of mineral wool product makes it possible to easily and effectively produce thin coating layers. This is beneficial for adhesion of a facing or for adhering two substrates together or when used as a fire-resistant or protective layer. Among other advantages, the thin layer does not increase the final weight of the mineral wool product.

[0049]

[0042] The mineral wool product with the coating layer provides an increased fire protection, compared to a mineral wool product coated with a conventional commercial fire paint based on organic polymer. For instance, when comparing an exemplary commercial fire paint coated mineral wool board with a similar mineral wool board with the coating layer according to an embodiment of the present invention, the commercial fire paint coated mineral wool board demonstrated an average fire performance (50 mm) at 60 minutes of 115 °C, while the mineral wool board with the coating layer according to one embodiment of the invention demonstrated an average fire performance (50 mm) at 60 minutes of 90 °C. Thus, it was seen that the fire-resistant coating layer extended the time it takes for the mineral wool board to reach its maximum temperature. The fire-resistant coating layer of the present invention may provide the benefit that it is non-combustible and it does not create smoke when exposed to fire. The coating layer of the present invention may provide effective fire protection up to 1,100 °C for at least 1.5 hours, or at least 2 hours, or even for at least 2.5 hours.

[0050]

[0043] According to another embodiment of the present invention, the coating layer can function as an adhesive or as an adhesive layer. It is possible to adhere, for example, a facing material to the first and / or second major surface of the mineral wool substrate by using the coating mixture. This is advantageous, as it does not only provide the necessary bonding for adhering the facing, but also increases or at least maintains the fire resistance properties of the obtained mineral wool product. Preferably, at least one facing material is adhered to the first major surface and / or the second major surface of the first mineral wool substrate with the coating layer. It was surprisingly found that the coating mixture, when applied to a surface of either a facing material or a mineral wool substrate, is capable of functioning as an adhesive layer or glue to secure the facing material to the substrate, once the coating mixture is cured and the coating layer is formed.

[0051]

[0044] The facing material may be selected from a fiberglass facing; nonwoven facing, such as nonwoven glass fiber mat or nonwoven polyester fiber mat; Kraft facing; or synthetic organic polymer facing, such as a polyethylene facing or a polypropylene facing. Preferably the facing material is an inorganic facing, such as fiberglass facing or nonwoven glass fiber mat. The facing may be in form of a scrim or a foil.

[0052]

[0045] The coating mixture can be used to adhere a fiberglass facing to the at least one major surface of the first mineral wool substrate with a median force peel strength of at least 30 N / m, at least 40 N / m or at least 50 N / m. According to one embodiment the fiberglass facing is adhered to the major surface of the first mineral wool substrate with a median force peel strength of at least 50 N / m, preferably at least 55 N / m, at least 60 N / m, at least 65 N / m, or at least 70 N / m. The median force peel strength described herein is determined as follows: The coating of a faced specimen, size 300 mm x 150 mm x 50 mm, is removed from its base material, using IJF6 / 500 Intelli-Jack 6 kN testing machine with 500N load cell and a 90° specimen holder, at a constant speed of 50 mm / min over a length of 40 mm, during which time the force required to remove the coating from the substrate was recorded. The final result is the median value divided by the width of the coating material.

[0053]

[0046] Alternatively, the coating mixture can be used to adhere a synthetic organic polymer facing to the at least one major surface of the first mineral wool substrate with a median force peel strength of at least 15 N / m. According to one embodiment the synthetic organic polymer facing, such as polyethylene facing, is adhered to the major surface of the first mineral wool substrate with a median force peel strength of at least 15 N / m, preferably at least 17 N / m, at least 20 N / m, or at least 25 N / m. The median force peel strength is determined as described above.

[0054]

[0047] According to one embodiment of the present invention the mineral wool product comprises a first mineral wool substrate comprising mineral fibers and having a first major surface and an opposed second major surface, and a second mineral wool substrate comprising mineral fibers and having a first major surface and an opposed second major surface. The coating layer is arranged between the major surfaces of the first and the second mineral wool substrates, wherein the coating layer adheres the first and the second mineral wool substrates together. For example, the coating mixture may be directly applied on the first or second maj or surface of the first mineral wool substrate, e.g. by spraying or vibration- assisted coating, and the first or second major surface of the second mineral wool substrate is then arranged on top of the coating mixture, whereafter the coating layer between the substrates is formed by curing and the substrates are adhered into a single mineral wool product. In general, the coating layer between the large surfaces of the first and the second mineral wool substrate achieves a strong and fire-resistant adhesion of the substrates.

[0055]

[0048] According to one embodiment of the present invention, the mineral wool product with the fire-resistant coating layer may be used in the production of a sandwich panel, for example, for use as a fire door. A sandwich panel comprises two mineral wool slabs (substrates) with the fire-resistant coating layer in between the slabs (substrates). Conventionally, prior the present invention, the fire door manufacturers had to increase the thickness of mineral wool slabs to fulfill the required fire safety standards. This naturally increased the cost, the material needed to manufacture such slabs as well the fire door weight. However, now it may be possible to reduce the slab thickness, fire door weight and the manufacturing costs by forming the fire-resistant coating layer between the mineral wool slabs as described above.

[0056]

[0049] The first mineral wool substrate suitable for the present invention comprises mineral fibers and has a first major surface and an opposed second major surface. The first and second major surfaces are typically parallel. The first mineral wool substrate is produced by using any conventional manufacturing processes known to those of ordinary skill in the art. In general, a process of making a mineral wool product includes a step of preparing a molten mineral melt. The molten mineral melt may be obtained by melting a variety of raw materials including, but not limited to, slags, various rocks and minerals, glass, and any combinations thereof. The used raw materials may comprise basalt, bauxite, dolomite, peridotite, diabase, gabbro, limestone, nepheline, syenite, silica sand, granite, clay, feldspar, phosphate-smelter slag, copper slag, blast furnace slag, or any of their mixtures. The raw materials are melted in a furnace, such as a cupola furnace or an electric furnace, to produce the molten mineral melt. The molten mineral melt is then fiberized using well-known internal or external centrifugation techniques to form a plurality of mineral wool fibers. The plurality of mineral wool fibers may be attenuated, for example, by a heated gas stream, and deposited or otherwise collected in the form of a mineral wool web. A binder composition may be applied to the mineral wool fibers when entrained in the heated gas stream or may be applied onto the mineral wool web. The binder composition may comprise a thermosetting resin. Exemplary binder compositions include, but are not limited to, carbohydrate-based binders, phenol-formaldehyde binders, urea-formaldehyde binders, melamine binders, and acrylic binders. In certain embodiments, the binder composition is a polyol-based binder and is substantially free of formaldehyde. In certain embodiments, the binder composition is a phenol-formaldehyde binder. The mineral wool substrate comprises 85 - 99.9 weight-%, preferably 90 - 99.5 weight-% of mineral fibers and 0.1 - 15 weight-%, preferably 0.5 - 10 weight-%, of binder. The mineral wool web may be consolidated by cross-lapping or another consolidation method, such as horizontal or vertical compression. After cross-lapping or other consolidation, the mineral wool web is cured in a conventional curing oven. After curing the mineral wool web is cut into mineral wool products of desired sizes and dimensions. The obtained mineral wool product may be, for example, a mineral wool slab, mineral wool board, mineral wool insulation batt, etc.

[0057]

[0050] The description above for the first mineral wool substrate fully applies to the second mineral wool substrate. The second mineral wool substrate comprises mineral fibers and may be produced with any of the methods described above. According to one embodiment of the invention, the second mineral wool substrate may be identical with the first mineral wool substrate. Alternatively, the second mineral wool substrate may be different form the first mineral wool substrate. The second mineral wool substrate may, for example, comprise mineral fibers that have different chemical composition and / or physical properties than the mineral fibers of the first mineral wool substrate.

[0058]

[0051] It is possible that the mineral wool product may be formed entirely of one type of mineral fibers, or it may be formed of a combination of two or more types of mineral fibers. For example, the mineral wool products may be formed of combinations of various types of different mineral fibers or various combinations of different mineral fibers and / or natural fibers depending on the desired application. Preferably the mineral wool substrate consists of mineral fibers.

[0059]

[0052] The coating layer may function as a fire-resistant layer, providing a hard fire- retardant surface for the mineral wool product. The coating layer may function as a protective layer, for example protecting the mineral wool product from impregnation of applied adhesives. Further, the coating layer may function as a strengthening layer, for improving the characteristics of hard mineral wool products. It is also possible that the coating layer functions as an adhesive, for example for attaching two mineral wool slabs together.

[0060]

[0053] According to one embodiment of the present invention, a facing material is adhered on the coating layer with an adhesive. The facing material may be a scrim, such a foil scrim kraft facing; a nonwoven facing, such as a nonwoven glass fiber mat or nonwoven polyester fiber mat; a composite facing, such as an all-service jacket facing; or a synthetic organic polymer facing, such as a polyethylene facing or a polypropylene facing. To adhere the at least one facing material to the surface of the coating layer, an adhesive or glue is applied to the surface of either the facing material itself or to the coating layer intended to receive the facing material.

[0061]

[0054] According to one embodiment of the present invention, the mineral wool product with the coating layer can be used for a bonded roof system. Bonded roof systems are formed using a facing material that is bonded using an adhesive, such as a polyurethane, to a mineral wool substrate. The coating layer, formed on a major surface of a mineral wool substrate by direct application prior to applying the adhesive, improves the adhesion between the mineral wool substrate and the adhesive. The coating layer may also function as a protective layer preventing the adhesive from penetrating into the mineral wool substrate. The bonded roof systems formed using a coated mineral wool substrate, i.e. mineral wool product, of the present invention may have a median force peel strength of at least 475 Newtons, including, for example, at least 485 Newtons, at least 500 Newtons, at least 525 Newtons, at least 550 Newtons, and at least 575 Newtons. The median force peel strength is determined in the same manner as described above, but using a 180° specimen holder.

[0055] In addition to good or improved fire resistance, the coating layer may also provide the mineral wool substrate with a hard surface layer that remains rigid even after exposure to a fire or high temperatures. To measure surface rigidity, the coating layer point load may be measured before and after exposure to fire, in accordance with EN 12430-04. An unbumed fire-resistant coating layer demonstrates typically a point load of at least 400 Newtons, including for example, at least 425 Newtons, at least 450 Newtons, at least 475 Newtons, at least 500 Newtons, at least 525 Newtons, and at least 550 Newtons. A burned fire-resistant coating layer which has been exposed to fire for at least 60 minutes demonstrates typically a point load of at least 300 Newtons, including for example, at least 325 Newtons, at least 350 Newtons, at least 375 Newtons, at least 400 Newtons, at least 425 Newtons, and at least 450 Newtons.

[0062]

[0056] According to one embodiment of the invention, the mineral wool product with the coating layer may further be a hard board product. Hard board products are mineral wool slabs (substrates) coated with the coating layer that provide a high compressive strength to the slab. Accordingly, the coating layer disclosed herein may be directly applied to a mineral wool substrate and cured to achieve a hard board product. In such embodiments, the coating layer may include reinforcement fibers, such as inorganic fibers (i.e., glass fibers), synthetic organic polymer fibers, and the like. The obtained hard board product, where the coating layer is optionally reinforced by fibers, may exhibit a depression of no greater than 5 mm under 1800 N pressure, including for example, a depression of no greater than 4 mm, no greater than 3.5 mm, no greater than 3 mm, no greater than 2.5 mm, and no greater than 2 mm.

[0063]

[0057] According to one embodiment, the coating layer is free of reinforcement fibers, such as inorganic fibers (i.e., glass fibers), synthetic organic polymer fibers, and the like.

[0064]

[0058] The mineral wool product described herein may be used to provide insulation, such as thermal insulation, acoustic insulation, and / or fire protection material to residential buildings or commercial buildings. In certain embodiments, the mineral wool insulation is suitable for use as a safing insulation and has a melting point of at least 1093 °C. In certain embodiments, the mineral wool insulation is suitable for use as a curtain wall insulation in a perimeter fire containment system. In certain embodiments, the mineral wool insulation is suitable for use as a pipe insulation.

[0065]

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which these exemplary embodiments belong. The terminology used in the description herein is for describing exemplary embodiments only and is not intended to be limiting of the exemplary embodiments. Accordingly, the general inventive concepts are not intended to be limited to the specific embodiments illustrated herein. Although other methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are described herein.

[0066]

[0060] As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Conversely, any reference to plural items shall, where appropriate, include the singular.

[0067]

[0061] Unless otherwise indicated, all numbers expressing quantities of ingredients, chemical and molecular properties, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present exemplary embodiments. At the very least, each numerical parameter should be construed in light of the number of significant digits and ordinary rounding approaches.

[0068]

[0062] Unless otherwise indicated, any element, property, feature, or combination of elements, properties, and features, may be used in any embodiment disclosed herein, regardless of whether the element, property, feature, or combination of elements, properties, and features was explicitly disclosed in the embodiment. It will be readily understood that features described in relation to any particular aspect described herein may be applicable to other aspects described herein provided the features are compatible with that aspect.

[0063] All ranges and parameters, including but not limited to percentages, parts, and ratios, disclosed herein are understood to encompass any and all sub-ranges assumed and subsumed therein, and every number between the endpoints. For example, a stated range of “1 to 10” should be considered to include any and all subranges between (and inclusive of) the minimum value of 1 and the maximum value of 10; that is, all subranges beginning with a minimum value of 1 or more (e.g., 1 to 6.1), and ending with a maximum value of 10 or less (e.g., 2.3 to 9.4, 3 to 8, 4 to 7), and finally to each number 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 contained within the range.

[0069]

[0064] The mineral wool product and corresponding use of the coating mixture of the present disclosure can comprise, consist of, or consist essentially of the essential elements and limitations of the disclosure as described herein, as well as any additional or optional ingredients, components, or limitations described herein or otherwise useful in mineral wool product applications.

[0070]

[0065] To the extent that the terms “include,” “includes,” or “including” are used in the specification or the claims, they are intended to be inclusive in a manner similar to the term “comprising” as that term is interpreted when employed as a transitional word in a claim. Furthermore, to the extent that the term "or" is employed (e.g., A or B), it is intended to mean “A or B or both A and B .” When it is intended to indicate “only A or B but not both,” then the term “only A or B but not both” will be employed. Thus, use of the term “or” herein is the inclusive, and not the exclusive use.

[0071] EXPERIMENTAL

[0072]

[0066] Some embodiments of the present invention are disclosed in the following nonlimiting examples.

[0073] Example 1

[0074]

[0067] Mineral wool slabs were produced and used to form a sandwich panel with a fire- resistant coating layer applied between two slabs as follows.

[0075]

[0068] A slab with a thickness of 60 mm, density 100 kg / m3, was cut to obtain two 30 mm thick slabs with identical major surface area than the original slab. Fire-resistant coating mixtures were synthesized by using microsilica or fumed silica and / or alumina, and / or metakaolin as particulate precursor material mixed with activator selected from aqueous solution of NaOH or water glass to obtain the stoichiometry described in Table 1. Examples 1, 2 and 4 comprise metakaolin. The coating mixture was spread directly onto the surface of one of the slabs and another slab was placed over it to create the sandwich panel. The sandwich panel was placed at 40 °C for 24 hours for curing the coating layer between the slabs.

[0076]

[0069] Reference sandwich panel sample 1 was formed without any coating between the slabs.

[0077]

[0070] The sandwich panel samples, 300 mm x 150 mm x 60 mm, were placed in a mineral wool frame of same wool quality and thickness, and installed in a vertical gas furnace with an opening of 490 mm x 415 mm, to be subjected to fire testing. The temperature curve of the test furnace was followed in accordance with EN 1363-1. Four thermocouples were placed on the cold side of the sandwich panel specimen to measure the temperature increase.

[0078]

[0071] The obtained results for the four sandwich panel samples 1 to 4 and for the reference sample 1 are illustrated Figure 1. Table 1 the shows obtained results for the four sandwich panel samples 1 to 4 in comparison to the reference sample, i.e. how much the time to reach the defined temperature is prolonged. Table 1 shows also how much lower (in degrees °C) the temperature is after 60 minutes, in comparison to the reference sample.

[0079]

[0072] It can be seen from the results of Figure 1 and Table 1 that all sandwich panel samples 1 to 4 demonstrated positive impact to the temperature raise. Despite very different stoichiometry of the applied coating mixture, all four coating layers exhibited good efficacy. Table 1 Stochiometry of tested coating mixtures and results of Example 1

[0080] Example 2

[0081]

[0073] One major surface of a mineral wool slab, thickness 60 mm, density 100 kg / m3, was directly coated with a coating mixture. The coating mixture comprised 51 wt.% of ground mineral wool as the first precursor, 15 wt.% of NaOH as the activator, and 22 wt.% of water. The ground mineral wool comprised alumina and silicon, and thus the particulate precursor material consisted of the first precursor, i.e. ground mineral wool. The coating mixture further comprised 12 wt.% of an intumescent additive (UltraCarb® LH15). The coated mineral wool slab was placed at 50 °C for 24 hours for curing the coating layer. The final coating weight was of 3.9 kg / m2. The coated mineral wool slab is denoted as Sample A.

[0082]

[0074] A comparative reference sample was prepared in the same manner but without the fire-resistant coating.

[0083]

[0075] Sample A and the reference sample, both 600 mm x 460 mm x 60 mm, were then subjected to fire testing in a vertical gas furnace, opening 490 mm x 415 mm. The temperature curve of the test furnace was followed in accordance with EN 1363-1. The coating layer side of Sample A was the side exposed to the fire.

[0084]

[0076] The obtained results are illustrated in Figure 2. It can be seen that the fire (temperature) curve of Sample A exhibits first a mild peak up to 75 °C. This can be attributed to the evaporation of water present in the coating layer. The mild peak is followed by a period about 15 min where the temperature decreased and then started to rise again. Nevertheless, Sample A demonstrated a clear delay in the temperature increase compared to the comparative reference example. At 40 minutes, the difference in temperature (delta T) between Sample A and the comparative reference is 70 °C and at 140 °C, the time difference is 12 minutes.

[0085] Example 3- Adhesion Testing

[0086]

[0077] Two set of mineral wool slabs were produced with facing material. In the first set the facing material was a glass fiber mat (GM) and in the second set the facing material was a spun-bond polyethylene fiber facing (PE). Both sets comprised test samples (GM1, PEI) where the facing material was adhered to the mineral wool slab with the coating layer, and reference samples where the facing material was adhered to the mineral wool slab with a conventional organic glue (refGM, refPE). Three parallel samples were prepared for the test samples and for the reference samples.

[0087]

[0078] A coating mixture comprising 57 wt.% ground stone wool waste as the first precursor, 17 wt.% of NaOH as the activator and 26 wt.% of water was mixed and applied to the surface of the facing material with a brush. The ground stone wool comprised alumina and silicon, and thus the particulate precursor material consisted of the first precursor, i.e. ground mineral wool. The facing material was then placed on the major surface of the mineral wool slab, and the faced slabs were placed at 40 °C for 24 hours for curing the coating layer. The total weight of the coating layer varied between 0.5 kg / m2to 1 kg / m2. The cured test samples were then subjected to a peel strength test where the facing material was removed from its substrate, 50 mm (Z) x 150 mm (Y) x 300 mm (X), at a constant speed of 50 mm / min over 40 mm length, during which the force values required to remove the facing material from the substrate were recorded.

[0088]

[0079] The results are illustrated in Figure 3. It can be seen that test samples GM1 and PEI where the facing material is adhered to the mineral wool substrate with the coating layer, demonstrated a peel strength between the facing material and the mineral wool substrate with a median force comparable to the one obtained when using a conventional organic glue when applied to a fiberglass facing material or a spun-bond polyethylene facing, reference samples refGM, refPE.

[0089] Example 4- Point Load

[0080] To measure surface rigidity of the coating layer, the coating layer point load was measured before and after exposure to fire. To measure point load in accordance with EN 12430-04, the coating layer was separated from the mineral wool substrate (both for the unbumed and burned sample). The separated coating layer was placed on top of an unburned, dense and hard mineral wool substrate. The coating layer was then subjected to the application of a concentrated load. The load at failure is used to calculate the point load strength index. The unburned coating layer formed in accordance with the present inventive concepts had a point load of about 530 Newton. For the burned sample of the same coating the point load was about 360 Newtons. Although it seems on basis of these results that the burned material might have a lower compressive strength, it still shows strength which is sufficient and improved over conventional organic paints.

[0090]

[0081] The scope of the general inventive concepts presented herein are not intended to be limited to the particular exemplary embodiments shown and described herein. From the disclosure given, those skilled in the art will not only understand the general inventive concepts and their attendant advantages, but will also find apparent various changes and modifications to the devices and systems disclosed. It is sought, therefore, to cover all such changes and modifications as fall within the spirit and scope of the general inventive concepts, as described and / or claimed herein, and any equivalents thereof.

Claims

CLAIMS1. A mineral wool product comprising:- a first mineral wool substrate comprising mineral fibers and having a first major surface and an opposed second major surface; and- a coating layer, formed directly on at least one of the first major surface or the second major surface of the first mineral wool substrate by application and curing of a coating mixture comprising:(i) a particulate precursor material comprising aluminum and silicon, wherein the particulate precursor comprises at least a first precursor selected from ground mineral wool, ground mineral fibers, metakaolin, slag, fly ash, silica-based minerals, or any mixtures thereof; and(ii) about 10 wt.% to about 70 wt.% of an activator, calculated from the total weight of the applied coating mixture.

2. The mineral wool product of claim 1, wherein the coating mixture comprises(i) 30 - 90 wt.%, preferably 35 - 85 wt.%, more preferably 45 - 80 wt.% or 50 - 75 wt.% or 55 - 70 wt.%, of the precursor material;(ii) 10 - 70 wt.%, preferably 15 - 65 wt.%, more preferably 20 - 55 wt.% or 25 - 50 wt.% or 30 - 45 wt.%, of the activator; calculated from the total weight of the applied coating mixture.

3. The mineral wool product of claim 1 or 2, wherein the coating layer is a foamed layer comprising closed gas-filled pores, wherein the coating mixture further comprises a foaming agent, such as at least one surfactant composition, an aluminum powder or any of their mixture.

4. The mineral wool product of claim 3, wherein the coating mixture comprises(i) 30 - 90 wt.%, preferably 35 - 85 wt.%, more preferably 45 - 80 wt.% or 50 - 75 wt.% or 55 - 73 wt.%, of the precursor material;(ii) 10 - 70 wt.%, preferably 15 - 65 wt.%, more preferably 20 - 55 wt.% or 25 - 50 wt.% or 27 - 45 wt.%, of the activator;(i) and (ii) calculated from the total weight of the coating mixture; and(iii) 0.05 - 50 wt.%, preferably 0.1 - 40 wt.%, more preferably 0.2 - 30 wt.% or 0.5 - 20 wt.%, of the foaming agent, based on total weight of (i) and (ii).

5. The mineral wool product of any one of claims 1 to 4, wherein the precursor material further comprises at least one co-precursor, which is different from the first precursor, and preferably selected from calcium-based minerals, such as gypsum, kaolinite, calcinated clay; phosphate-based minerals; or any mixture thereof.

6. The mineral wool product of claim 5, wherein the precursor material comprises- 0.5 - 99.9 wt.%, preferably 5 - 85 wt.%, more preferably 10 - 75 wt.% or 15 - 65 wt.% or 20 - 50 wt.%, of the first precursor, and- 0.1 - 99.5 wt.%, preferably 15 - 95 wt.%, more preferably 25 - 90 wt.% or 35 - 85 wt.% or 50 - 80 wt.%, of the co-precursor.

7. The mineral wool product of any one of claims 1 to 6, wherein the activator is- an alkali-activator, preferably selected from one or more of an alkali hydroxide, alkali silicate, alkali aluminate, alkali sulfate, alkali carbonate, or any mixtures thereof; or- an acid-activator, preferably selected from phosphonic acid, phosphoric acid, carboxylic acid, or any mixture thereof.

8. The mineral wool product of any one of claims 1 to 7, wherein the formation of the coating layer is achieved by application of the coating mixture by a roller, by brushing, spraying, dipping, or by spin coating, flow coating, by curtain coating or by mechanical vibration- assisted coating.

9. The mineral wool product of any one of claims 1 to 8, wherein the cured coating layer has- a layer weight in a range of 0.2 - 100 kg / m2, preferably 0.5 - 80 kg / m2, more preferably 0.8 - 65 kg / m2or 1 - 50 kg / m2or 1.75 - 40 kg / m2; and / or- a thickness of no greater than 10 mm, preferably 0.1 - 8 mm, more preferably 0.25 - 6 mm.

10. The mineral wool product of any one of claims 1 to 9, wherein a facing material is adhered on the coating layer with an adhesive.

11. The mineral wool product according to any one of claims 1 to 10, wherein at least one facing material is adhered with the coating layer to the first major surface and / or the second major surface of the first mineral wool substrate.

12. The mineral wool product of claim 10 or 11, wherein the facing material is selected from a fiberglass facing, nonwoven facing, Kraft facing or synthetic organic polymer facing.

13. The mineral wool product of any one of claims 1 to 12, wherein the mineral wool product comprises a second mineral wool substrate comprising mineral fibers and having a first major surface and an opposed second major surface, wherein a coating layer is arranged between the major surfaces of the first and the second mineral wool substrates for adhering the mineral wool substrates together.

14. Use of a coating mixture for manufacturing of a mineral wool product comprising a first mineral wool substrate comprising mineral fibers, the coating mixture comprising:(i) a particulate precursor material comprising aluminum and silicon, wherein the particulate precursor comprises at least a first precursor selected from ground mineral wool, ground mineral fibers, metakaolin, slag, fly ash, silica-based minerals, or any mixtures thereof; and(ii) about 10 wt.% to about 70 wt.% of an activator, calculated from the total weight of the applied coating mixture15. Use according to claim 14, wherein the coating mixture is used to provide- a fire-resistant coating layer or a protective coating layer on a surface of the mineral wool substrate, or- an adhesive layer between the first mineral wool substrate and a second mineral wool substrate and / or between the first mineral wool substrate a facing material.

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