WO2025046040A1

WO2025046040A1 - Mineral wool binder based on phenol formaldehyde resin and carbohydrate

Info

Publication number: WO2025046040A1
Application number: PCT/EP2024/074234
Authority: WO
Inventors: Thomas Hjelmgaard; Martin Spangsberg Holm; Josefine OEGAARD SVENDSEN; Lars Naerum; Freek VAN DER EERDEN
Original assignee: Rockwool A/S
Priority date: 2023-09-01
Filing date: 2024-08-29
Publication date: 2025-03-06

Abstract

The invention is directed to an aqueous binder composition for mineral wool fibres made of a mixture of I) a phenol-urea-formaldehyde binder (PUF binder), and II) a carbohydrate binder comprising a component (a) in the form of one or more carbohydrates and a component (b) in the form of: (bi) one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof, wherein component (a) is present in an amount of at least 20 % by weight based on the binder component solids. The aqueous binder composition is suitable for producing a mineral fibre product by contacting mineral fibres with the aqueous binder composition and curing the binder.

Description

Postfach 860624 81633 München ROCKWOOL A/S August 29, 2024 Hovedgaden 584 M/ROCK-180-PC 2640 Hedehusene DENMARK _______________________________________________________________ Mineral wool binder based on phenol formaldehyde resin and carbohydrate ________________________________________________________________ Description Field of the Invention The present invention relates to an aqueous binder composition comprising a mixture of a phenol-urea-formaldehyde binder and a carbohydrate binder, a method of producing a mineral wool product with the aqueous binder composition, and the mineral wool product prepared by the method. Background of the Invention Mineral wool products generally comprise man-made vitreous fibres (MMVF) such as, e.g., glass fibre, ceramic fibres, basalt fibres, slag wool, mineral wool and stone wool (rock wool), which are bonded together by a cured thermoset polymeric binder material. For use as thermal or acoustical insulation products, bonded mineral fibre mats are generally produced by converting a melt made of suitable raw materials to fibres in a conventional manner, for instance by internal centrifugation (spinning cup process) or by external centrifuging (cascade rotor process). The fibres are blown into a forming or spinning chamber and, while airborne and still hot, are sprayed with a binder solution and randomly deposited as a mat or web onto a travelling conveyor. The fibre mat is then transferred to a curing oven where heated air is blown through the mat to cure the binder and rigidly bond the mineral fibres together. Phenolic binders, in particular phenol-formaldehyde resole resins are frequently used in the manufacture of mineral fibre insulation materials, such as insulative batts for walls, roof boards, ceiling tiles, insulative coverings for pipes, and the like. Typically, when a phenol-formaldehyde resole resin is used as a binder, a significant amount of formaldehyde is released into the environment during processing, in particular during application of the binder on mineral fibres in a spinning chamber and curing. Formaldehyde can also be released subsequently from the cured resin. Such formaldehyde emissions are undesirable, particularly in enclosed spaces, because it is hazardous to human health, and to the environment. Formaldehyde has been classified as carcinogenic to humans by The International Agency for Research on Cancer (IARC) of the World Health Organization (WHO); see the IARC Monograph on Formaldehyde, Volume 88 (2006). It is therefore desirable to reduce the release of formaldehyde into the environment. Various techniques have been used to reduce the formaldehyde emission from formaldehyde-based resins. In particular, various formaldehyde scavengers have been used for that purpose. For instance, urea acts as a formaldehyde scavenger both at, and subsequent to, the manufacture of bonded mineral fibre products. Urea is typically added directly to the phenol-formaldehyde resin to produce a urea-modified phenol-formaldehyde resole resin also called phenol-urea- formaldehyde resole resin. To obtain a typical urea-modified resole binder resin, a mixture of phenol and formaldehyde is reacted with a suitable catalyst in one or more steps. The reaction conditions, temperature, amount of catalyst, etc. are adjusted to favour phenol methylation reaction over condensation reactions. Urea is then added before or after inactivating the resin just prior to use of the resin. Such a resin is typically referred to as a PUF resin, or PUF binder. For instance, US-A-4339361 discloses phenol-formaldehyde resole resins which are suitable for use in binder systems for bonding mineral fibre products and which are extended with an amide or amine such as urea and a sugar as inexpensive extenders. The sugar component may be selected from mono- and oligosaccharides and water-soluble polysaccharides. Modification of phenol-urea-formaldehyde binders with ammonia as a formaldehyde scavenger is also a known method to reduce the formaldehyde emission of the binders during use. On the other hand, the modification with ammonia increases the ammonia emission of these systems. This is a particular problem when such binders are applied to mineral fibres in a spinning chamber. As mentioned above, mineral fibres when produced are blown into such a spinning chamber and are still hot. Under these conditions, the volatiles present in the uncured binders will be evaporated during application. As a result, a relative high ammonia emission is caused when such binders are applied on the mineral fibres in the spinning chamber which is highly undesirable. Such ammonia emissions are likewise undesirable, particularly in enclosed spaces, because it is hazardous to human health, and to the environment. Various techniques have been used for lowering both the formaldehyde and the ammonia emissions from formaldehyde-based resins. In particular, sugar components have been used for this purpose, as sugar will react with ammonia in the phenol-formaldehyde resin in a Maillard reaction during curing thus significantly repressing the ammonia emission. For instance, WO96/26164 describes a phenol-formaldehyde resin composition for use as a binder in mineral wool products wherein the emission of phenol is reduced by using stoichiometric excess of formaldehyde over phenol, wherein the emission of the excess formaldehyde is reduced by adding ammonia as a formaldehyde scavenger and wherein the emission of ammonia is reduced by reacting the ammonia with a sugar compound. The sugar compound may be selected from monosaccharides, disaccharides and polysaccharides. WO2012/076462 relates to a method of reducing the formaldehyde emission of a mineral fibre product bonded with a urea-modified phenol-formaldehyde resol resin-type binder where dextrose is added to the uncured binder composition functioning as a formaldehyde scavenger. US2014/0113123 relates to a lignin based binder comprising lignosulfonic acid salt, thermosetting resin chosen from phenolic resin or urea formaldehyde resin, a curing catalyst and an oligosaccharide as a filler. The lignosulfonic acid salt replaces in part the thermosetting resin thereby reducing the content of free formaldehyde. WO2016/10244 A1 relates to an aqueous binder composition for mineral fibres comprising a component (i) in form of one or more carbohydrates, a component (ii) in form of one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof. This aqueous binder composition is a formaldehyde free binder having a formaldehyde product emissions below the limits mentioned below, when tested according to the ISO 16000:2021 standard. US-A-2010/0075146 relates to a sizing composition for mineral fibres aimed at reducing undesirable emissions which comprises phenol-urea-formaldehyde resin and a catalyst made of a mixture of ammonium sulfamate and ammonium sulfate. The sizing is extended with saccharide as inexpensive extender. The saccharide component may be sugar cane or beet molasses. Such binders based on phenol-formaldehyde resole resins making use of formaldehyde scavengers, such as urea or ammonia, as well as sugar as an ammonia scavenger exhibit favourable lower formaldehyde emissions and ammonia emissions compared to conventional phenolic binders. However, compared to the known conventional phenolic binders mentioned above there are still some drawbacks in terms of the curing temperatures being higher and the mechanical properties being at best equal to or lower than that of conventional phenolics binders. Phenol-formaldehyde binders with carbohydrates can show in its cured state a higher solubility and higher water absorption which are undesirable properties as it impairs it use in certain application fields. Accordingly, there is still a need to provide an aqueous binder composition based on phenol-formaldehyde type binder suitable for bonding mineral fibres to prepare mineral fibre products, wherein the binder composition generates only small amount of harmful gases during processing. In particular, the ammonia, formaldehyde and phenol emissions shall be reduced and kept low. At the same time mineral fibre products resulting from applying the binder to mineral fibres and curing shall have very good long term mechanical properties and a satisfactory low water uptake (or water absorption) and a low solubility. Summary of the Invention Accordingly, it was an object of the present invention to provide an aqueous binder composition suitable for bonding mineral fibres which overcomes or alleviates the drawbacks of the prior art discussed above. Specifically, it was an object of the present invention to provide a phenol-urea- formaldehyde based binder for mineral fibres having a reduced ammonia emission during processing of the binder while the formaldehyde and phenol emissions are still kept low, in particular during application of the binder on mineral fibres in a spinning chamber where the temperature of the fibres is still elevated. At the same time the binder in the cured state should show satisfactory properties with respect to mechanical strength, solubility and water absorption. The inventors surprisingly found that the object can be solved by providing a binder composition made of a mixture of phenol-urea-formaldehyde type binder (PUF binder) and a particular carbohydrate binder. In accordance with a first aspect of the present invention, there is provided an aqueous binder composition in particular for mineral fibres made of a mixture of I) a phenol-urea-formaldehyde binder (PUF binder), and II) a carbohydrate binder comprising: a component (a) in the form of one or more carbohydrates; a component (b) in the form of: (bi) one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof, wherein component (a) is present in an amount of at least 20 % by weight based on the binder component solids. The present inventors have surprisingly found that the mixed binder as described herein provides improved mechanical properties as compared to both the pure PUF binder and the pure carbohydrate binder. In particular, the addition of the particular carbohydrate binder to the PUF binder can not only reduce the ammonia emission but also the formaldehyde and phenol emissions during processing, in particular during application of the binder on mineral fibres in a spinning chamber. In PUF binders modified with ammonia as formaldehyde scavenger, the addition of the carbohydrate binder does not only result in a drastic reduction of ammonia emission but also significantly reduces formaldehyde and phenol emissions. In general, the reduction in ammonia emission is proportional to the substitution level, whereas the reduction in formaldehyde and phenol emissions are even more pronounced A PUF binder not including ammonia as a formaldehyde scavenger removes most of the ammonia emission but also results in a very high formaldehyde emission. This formaldehyde emission in an ammonia free PUF binder can then be strongly decreased by partial substitution with the carbohydrate binder. As a result, the inventive mixture of PUF binder (Component (I)) and carbohydrate binder (Component (II)) can reduce the ammonia, formaldehyde and phenol emissions as compared to a pure PUF binder. This opens for the possibility of partial or complete removal of ammonia from the aqueous binder composition described herein. The inventive mixed binders usually retain the mechanical strength compared to pure PUF or are at a comparable level and in most cases even significantly improve the mechanical strength when compared to pure carbohydrate binders. Especially the aged mechanical strength is generally significantly improved compared to both pure PUF binder and carbohydrate binders. When starting from the carbohydrate binder, the addition of the PUF binder also results in significant improvements as compared to the pure carbohydrate binder. As discussed above, drawbacks of pure carbohydrate binders are a relatively high water uptake in the cured state. However, even small amounts of PUF binder mixed into a carbohydrate binder result, after curing, in an insoluble binder with lowered water uptake. Without being bound by theory, this indicates that the PUF binder is very efficient as crosslinker for carbohydrate binders. The improvements described for the mixed binders are to such an extent that they generally cannot be explained by additive effects but shows a synergistic interaction between the two binder systems mixed. Further advantages and features of the present invention will emerge from the description of preferred embodiments as well as from the drawing, which shows: Fig.1 shows a comparison between the invention and prior art of unaged and aged mechanical strengths of composite bars, where composite bars bonded by pure PUF binder is depictured as (A) in the graph, composite bars bonded by three different mixtures of binders as described herein are depictured as Ex.1-3, composite bars bonded by pure carbohydrate binder is depictured as (C2), composite bars bonded by a prior art carbohydrate binder (D1-D3), and composite bars bonded by dextrose alone is depictured as (B). Fig.2 shows a comparison of simulated spinning chamber emissions of a pure PUF binder (A), the carbohydrate binder in three different mixtures of binders as described herein (Ex.1 – 3) and a pure carbohydrate binder (C2). Description of the preferred embodiments The present invention is directed to an aqueous binder composition for mineral fibres made of a mixture of I) a phenol-urea-formaldehyde binder (PUF binder), and II) a carbohydrate binder comprising: a component (a) in the form of one or more carbohydrates; a component (b) in the form of: (bi) one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof, wherein component (a) is present in an amount of at least 20 % by weight based on the binder component solids. The aqueous binder composition of the present invention is a mixed binder composition obtainable by mixing two stand-alone binders, namely a phenol-urea- formaldehyde binder and a carbohydrate binder. Here, the phenol-urea- formaldehyde binder is also called PUF binder which is a common designation for such binder systems. Stand-alone binders are generally complete binders which can be used as such a binder. In a preferred embodiment, the aqueous binder composition of the present invention is a mixed binder composition obtainable by in-line mixing of - a stand-alone phenol-urea-formaldehyde binder (PUF), - component (a) in the form of one or more carbohydrates, - component (b) in the form of: (bi) one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof, - optionally component (bii) in the form of one or more compounds selected from hypophosphorous acid, derivatives of hypophosphorous acid or any salt thereof, - optionally ammonia - optionally urea - optionally silane - water. In a preferred alternative embodiment, the aqueous binder composition of the present invention is a mixed binder composition obtainable by in-line mixing of - a phenol-urea-formaldehyde resin, - ammonia - ammonium sulfate - component (a) in the form of one or more carbohydrates, - component (b) in the form of: (bi) one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof, - optionally component (bii) in the form of one or more compounds selected from hypophosphorous acid, derivatives of hypophosphorous acid or any salt thereof - optionally urea - optionally silane - water. The in-line mixing is preferably performed using static mixers. Alternatively, the in-line mixing is performed via fixed installations through which the mixture has to flow, whereby mixing is carried out as a result of the flowing through. The aqueous binder composition of the present invention as well as both the PUF binder and the carbohydrate- binder are particularly suitable as a binder for mineral fibres in order to produce mineral fibre products. The binder composition of the present invention is an aqueous binder composition, i.e. the binder composition contains water. Usually, both the PUF binder and the carbohydrate binder are aqueous binders. Water can be added to the mixture, if necessary, for instance, in order to adjust the desired properties such as viscosity. Component (I) - PUF binder Phenol-urea-formaldehyde binders (PUF binders) which are based on a phenol- urea-formaldehyde resin (PUF resin) are well-known to the skilled person and have a broad range of applications, for instance as a binder for mineral fibres in the production of mineral fibre products. In accordance with the present invention, the nature of the PUF binder is not critical, and any PUF binder known in the art may be used. A PUF binder which is a mixture of phenol formaldehyde binder (PF binder) and urea formaldehyde binder (UF binder) may be also used. Starting materials for preparing a PUF binder based on PUF resin are generally phenol, urea, formaldehyde and a base as a catalyst. Optionally further materials can be used in the reaction, such as formaldehyde scavengers such as ammonia, and hardening agents such as ammonia salts, such as ammonium sulfate. Formaldehyde can be introduced into the reaction, for instance, as an aqueous solution (formalin) or in form of para-formaldehyde. The base used in the process of preparing the PUF resin or binder can include at least one basic alkali metal or alkaline earth metal compound or amine catalyst, such as triethyl amine (TEA). Examples of alkali metal bases which can be used include the hydroxides of sodium, potassium and lithium. Examples of alkaline earth metal bases which can be used include the oxides and hydroxides of calcium, barium and strontium, such as calcium oxide and calcium hydroxide. The PUF binder used for the aqueous binder composition described herein is typically a phenol-urea-formaldehyde resole binder. Resole resins or resole-type binders, respectively are obtained by use of a stoichiometric excess of formaldehyde with respect to phenol, i.e. the molar ratio of aldehyde to phenol is greater than 1. Specific examples of suitable PUF resol resins or binders are, for instance, those disclosed in EP-A-148050, EP-A-810981, CA-A-1001788 and US-A-5371140; the emulsifiable phenolic resins disclosed in EP-A-1084167; the overcondensed phenolic resins disclosed in WO 99/03906 and WO 2009/136106. The production of PUF binders or PUF resins, respectively, typically involves the reaction of phenol and formaldehyde in aqueous alkaline solutions to prepare phenol formaldehyde resins. Urea can be introduced during or after the resin preparation to achieve the phenol-urea-formaldehyde resin. In a preferred embodiment, the molar ratio of phenol to formaldehyde used for preparing the PUF binder is from 1:2.5 to 1:6; preferably from 1:3 to 1:5. In a preferred embodiment, the amount of urea used for preparing the PUF binder is from 20 to 60 % by weight, preferably 30 to 50 % by weight, based on total weight of phenol, formaldehyde and urea used for preparing the PUF binder. More specifically, an exothermic condensation reaction of the phenol and the aldehyde is initiated after mixing the phenol and the aldehyde by addition of the base in aqueous solution. For example, an aqueous mixture of phenol and formaldehyde can be maintained at a first temperature of, for instance, 40 to 50°C, as the basic catalyst is added. The temperature can then be permitted to rise to a second reaction temperature of, for instance, 60 to 90°C. In an alternative embodiment, the aqueous mixture of phenol and formaldehyde can be heated in the presence of a base with a continuous heating rate of, e.g., 0.5°C/min to 1.5°C/min, such as about 1°C/min, up to an end temperature of e.g.60°C to 90°C, e.g. about 84°C, and maintained at the end temperature for a certain time. Preferably, the reaction of phenol and formaldehyde is carried out for a sufficient reaction time and at a suitable temperature to provide a resin, preferably a resol resin, having an acid tolerance of < 8, preferably within the range of 0.5 to 7, more preferably 3 to 5. Acid tolerance is a measure of the reaction degree. A method for its determination is given in the experimental part below. The degree of conversion of phenol is preferably > 95%, more preferably > 97%. The urea may be added to the resin, in particular the resol resin, during its preparation or in a post-reaction step. The PUF resin or PUF binder can be a PUF resin or PUF binder which is modified with ammonia. Alternatively, the PUF resin or PUF binder can be a PUF resin or PUF binder which is not modified with ammonia. As mentioned, ammonia can serve as a formaldehyde scavenger. It is preferred that the PUF binder is modified with ammonia. The modification of the PUF resin or PUF binder with ammonia is carried out by addition of ammonia, for instance as a gas but usually in form of an aqueous solution of ammonia, to the reaction material or PUF resin, preferably after the formation of the phenol-urea- formaldehyde resin or phenol-urea-formaldehyde resole resin. It should be noted that ammonia here only means ammonia as such, i.e. it does not include ammonium salts, which may be added as additives. This applies also to the following indications as to the suitable amounts. In a preferred embodiment, the amount of ammonia is 0 to 6 % by weight, more preferably 0 to 4 % by weight, more preferably 0 to 3 % by weight, based on the binder component solids of the PUF binder. As mentioned, the PUF binder is more preferably modified with ammonia and in that case, a suitable lower limit of ammonia may be, for instance, at least 0.1 % by weight, based on the binder component solids of the PUF binder. Thus in the case of modification with ammonia, the amount of ammonia may be for instance 0.1 to 6 % by weight, preferably 0,5 to 4 % by weight, more preferably 1 to 3 %, based on the binder component solids of the PUF binder. The binder component solids of the PUF binder is defined below with respect to the description of the mixture. The aqueous composition obtained containing the PUF resin, preferably PUF resole resin, can be used as the PUF binder for the aqueous binder composition of the present invention. Optionally, water may be added to adjust the viscosity of the PUF binder. Moreover, additives can be optionally added to the PUF binder. A hardening agent may be added to the reaction mixture such as ammonium sulphate or an acid such as sulfuric acid. Component (II) – Carbohydrate binder The second binder making part of the aqueous binder composition described herein is a carbohydrate binder comprising - a component (a) in the form of one or more carbohydrates and - a component (b) in the form of: (bi) one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof. The carbohydrate binder is usually an aqueous binder. The binder can contain one or more carbohydrates. Moreover, the carbohydrate binder is a formaldehyde-free binder as no formaldehyde is added. For the purpose of the present application, the term “formaldehyde-free” is also defined to characterize a mineral wool product with cured binder where the emission is below 5 μg/m²/h of formaldehyde from the mineral wool product, preferably below 3 μg/m²/h. Preferably, the test is carried out in accordance with ISO 16000:2021 for testing aldehyde emissions. Component (a) of the binder Component (a) is in the form of one or more carbohydrates. Starch may be used as a raw material for various carbohydrates such as glucose syrups and dextrose. Depending on the reaction conditions employed in the hydrolysis of starch, a variety of mixtures of dextrose and intermediates is obtained which may be characterized by their DE number, DE is an abbreviation for Dextrose Equivalent and is defined as the content of reducing sugars, determined by the method specified in International Standard ISO 5377-1981 I. This method measures reducing end groups and attaches a DE of 100 to pure dextrose and a DE of 0 to pure starch. In a preferred embodiment, the carbohydrate is selected from sucrose, reducing sugars, in particular dextrose, polycarbohydrates, and mixtures thereof, preferably dextrins and maltodextrins, more preferably glucose syrups, and more preferably glucose syrups with a dextrose equivalent value of DE = 30 to 100, such as DE = 50 to 100, such as DE = 60 to 100, such as DE = 85 to 100, such as DE = 95 to 100. The term “dextrose” as used in this application is defined to encompass glucose and the hydrates thereof such as D-glucose. In a preferred embodiment, the carbohydrate is having a DE value of 60 to 100, in particular 85 to 100, more particular 95 to 100. In a preferred embodiment, the carbohydrate is a dextrose having a DE value of 85 to 100. In a further preferred embodiment, the carbohydrate is selected from hexoses, in particular allose, altrose, glucose, mannose, gulose, idose, galactose, talose, psicose, fructose, sorbose and/or tagatose; and/or pentoses, in particular arabinose, lyxose, ribose, xylose, ribulose and/or xylulose; and/or tetroses, in particular erythrose, threose, and/or erythrulose. In a further preferred embodiment, the carbohydrate is selected from a hexose such as fructose, and/or a pentose such as xylose. The carbohydrate binder component (a) is present in an amount of at least 20 % by weight based on the binder component solids. In a preferred embodiment, the component (a) is present in an amount of between 20 to 90 % by weight of binder component solids, more preferably in an amount of between 40 to 90 % by weight of binder component solids, most preferably in an amount of between 60 to 80 % by weight of binder component solids. Since the carbohydrates of component (a) are comparatively inexpensive compounds and are produced from renewable materials, the inclusion of high amounts of component (a) in the carbohydrate binder allows for an ecological and economic advantageous production of the binder. Component (b) of the binder Component (b) of the binder is in the form of: (bi) one or more compounds selected from one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof, and alternatively (bii) one or more compounds selected from hypophosphorous acid, derivatives of hypophosphorous acid or any salt thereof. In a preferred embodiment, the proportion of component (b) of the aqueous carbohydrate binder composition is within the range of 1 to 15 wt%, in particular 1-12 wt%, more particular 2-10 wt% based on binder component solids. Component (bi) of component (b) In one embodiment of the invention, component (bi) is in the form of one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof. Sulfamic acid is a non-toxic compound having the formula

Sulfamic acid and many of its salts are storage stable non-volatile compounds and are available at a comparatively low price. In a preferred embodiment, component (bi) is selected from the group consisting of sulfamic acid and any salt thereof, such as ammonium sulfamate, calcium sulfamate, sodium sulfamate, potassium sulfamate, magnesium sulfamate, cobalt sulfamate, nickel sulfamate, N-cyclohexyl sulfamic acid and any salt thereof, such as sodium N- cyclohexyl sulfamate. In a preferred embodiment, the proportion of component (bi) of the aqueous carbohydrate binder composition is within the range of 0.5-20 wt%, in particular 1-15 wt%, more particular 1-10 wt% such as 2-10 wt%, most particular 1-5 wt% based on binder component solids. In a preferred embodiment, component (bi) is sulfamic acid. In a particular preferred embodiment, component (bi) is ammonium sulfamate. In another preferred embodiment, the component (bi) is in form of N-cyclohexyl sulfamic acid and any salt thereof. The proportion of component (bi) in form of N- cyclohexyl sulfamic acid and any salt thereof is within the range of 0.5-20% by weight, in particular 1-15% by weight, more particular 1-10% such as 2-10 %, most particular 1-5 % by weight based on the mass of binder component solids. An advantage of the binder component (bi) is that it helps lowers the curing temperature and the reaction loss during curing. A lower reaction loss will result in lower emissions. Furthermore, it has a comparatively low price and being easy to handle. Component (bii) of component (b) In an embodiment of the invention, component (b) of the carbohydrate binder further comprises a component (bii) in the form of one or more compounds selected from hypophosphorous acid, derivatives of hypophosphorous acid or any salt thereof. Hypophosphorous acid, H³PO² (or H²PO(OH)), is a mineral acid having the formula

component (bii) is hypophosphorous acid. In a further preferred embodiment, component (bii) is ammonium hypophosphite or sodium hypophosphite. In a preferred embodiment, component (b) is a mixture of component (bi) and (bii), i.e. a mixture of sulfamic acid, derivatives of sulfamic acid or any salts thereof and hypophosphorous acid, derivatives of hypophosphorous acid or any salts thereof. In a preferred embodiment, the proportion (binder component solids) of component (bii) of the aqueous carbohydrate binder composition is within the range 0.25 to 10 wt%, in particular 0.5 to 7.5 wt%, more particular 0.5 to 5 wt% based on binder component solids. It has surprisingly been shown that by adding a mineral acid such as hypophosphorous acid to the aqueous binder composition, the mechanical properties of the aqueous carbohydrate composition can be strongly improved. Component (bii) can be used as the single component in component (b) of the carbohydrate binder part of the inventive aqueous binder composition. However, a disadvantage of using only component (bii) in the carbohydrate binder part of the aqueous binder composition as described herein is the comparatively high price. The present inventors have found that by including component (b) as a mixture of component (bi) and component (bii) to the aqueous binder composition, both the unaged and aged mechanical strength of the aqueous binder composition described herein can be strongly improved. In a further preferred embodiment, the ratio of component (bi) to component (bii) is ≥1:1, more preferably between 3:1 and 5:1, most preferably 4:1 in the aqueous binder composition. In particular, the present inventors have found that the addition of component (bii), i.e. hypophosphorous acid, derivatives of hypophosphorous acid or any salt thereof in a ratio of 4:1 of component (bi) to component (bii) nearly doubles the aged mechanical strength compared to only including component (bi), i.e. sulfamic acid, derivatives of sulfamic acid or any salts thereof in the aqueous binder composition according to the invention. Further, the temperature of curing onset and curing endset of the aqueous binder of the present invention can be reduced by including a mixture of component (bi) and component (bii) in the aqueous binder as compared to only adding component (bi). In a preferred embodiment, the carbohydrate binder composition further comprises a component (c) in the form of ammonia. The amount of ammonia is preferably present in an amount of 0.01 to 2 % by weight, more preferably 0.01 to 1 % by weight based on the binder component solids. In an alternative embodiment component (c) is preferably in the form of an ammonium salt. Without wishing to be bound by any theory, it is assumed that ammonia crosslinks strongly with the aldehyde groups of the carbohydrate thus resulting in the inventive mixture of the PUF binder and carbohydrate binder can reduce both the ammonia and formaldehyde emission as compared to pure PUF binder. In a further preferred embodiment, the aqueous carbohydrate binder composition further comprises a component (d) in the form of urea. The amount of urea is preferably present in an amount of 0.5 to 6 % by weight, more preferably 1 to 5 % by weight, most preferably 2 to 4 % by weight, based on the weight of binder component solids. The inclusion of urea in the binder described herein improves the fire resistance and anti-punking properties of the inventive binder. Final binder composition - mixing of component (I) and component (II) In accordance with the present invention the carbohydrate binder composition for mineral fibres is based on the combination of a carbohydrate component (a) and a component (b) selected from one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof, and optionally one or more compounds selected from hypophosphorous acid, derivatives of hypophosphorous acid or any salt thereof, or any mixture thereof. It is highly surprising that by the combination of these two components (a) and (b), binder compositions can be prepared which are suitable for bonding mineral fibres. Both these components have a comparatively low price and are easy to handle. The aqueous binder composition of the present invention can be obtained e.g. by adding the carbohydrate binder (component (II)) to the phenol-urea-formaldehyde binder (component (I)) or vice versa and, if necessary, mixing the mixture obtained with a mixing device. Common mixing devices such as mixing tanks or static mixers can be used. In order to obtain the aqueous binder composition of the invention, it is preferred that the PUF binder and the carbohydrate binder are mixed in a ratio such that the proportion by weight B, based on the combined weight of A+B, is in the range of 20 to 95% by weight, more preferably 25 to 95% by weight, wherein B is the weight of the binder solids of the carbohydrate binder (component II) and A is the weight of the binder solids of the PUF binder (component (I)). More preferably, the proportion by weight B, based on the combined weight A+B, may for example be suitably in the range of 25 to 90% by weight of the binder solids. The present invention can also be used to improve the characteristics of the PUF binder or the carbohydrate binder depending on whether the PUF binder or the carbohydrate binder is the main component of the aqueous binder composition of the invention. Thus, in case the PUF binder is the main component of the aqueous binder composition of the invention, the proportion by weight B, based on the combined weight A+B, is preferably in the range of 5 to 50% by weight, more preferably 10 to 45% by weight, even more preferably 15 to 40 % by weight or 20 to 40 % by weight or 25 to 40 % by weight of binder solids. As can be seen from the experimental part below and figure 2, even low proportions of the carbohydrate binder (component II) mixed into the PUF binder (component (I)) result in a significant reduction of ammonia and especially a significantly high reduction of formaldehyde and phenol emissions in a PUF binder modified with ammonia. A significant reduction of formaldehyde emission in a PUF binder not modified with ammonia as compared to the pure binder is also obtained. In case the carbohydrate binder is the main component of the aqueous binder composition of the invention, the proportion wherein the proportion by weight B, based on the combined weight of A+B, is preferably in the range of 50 to 95% by weight, more preferably 55 to 90% by weight, more preferably 60 to 80% by weight. In other words, the proportion by weight A, based on the combined weight of A+B, is preferably in the range of 5 to 50% by weight, more preferably 10 to 45% by weight, most preferably 20 to 40% by weight. As can be seen in the experimental part below, even low proportions of the PUF binder mixed into the carbohydrate binder result in a reduction in water absorption in a resulting binder as compared to the carbohydrate binder itself. Moreover, the inventive aqueous binder composition described herein as compared to both the pure PUF binder and the pure carbohydrate binder result in very good mechanical strengths of mineral fibre products produced with the inventive binder. From figure 1 it can be seen that both the unaged (top two curves) and aged (lower two curves) mechanical strengths of mineral fibre products produced with the inventive binder (depictured as Ex.1 (25:75), Ex 2. (50:50) and 3 (75:25)) in general are higher than that of the prior art carbohydrate binder (depictured as D1-D3) and pure dextrose (depictured as (B)). Though, the experimental part and figure 1 show a slight decrease in unaged mechanical strengths when compared to the pure PUF binder (depictured as (A)), the aged mechanical strengths are generally significantly improved. The binders described herein can be of any pH. Preferably, the binders have a pH of 6-11, preferably a pH of 7-11. In a particular preferred embodiment, the binders have a pH of 7-10. Accordingly, the binder of the present invention is not strongly acidic and thus not strongly corrosive. In the context of the present invention, the “binder component solids” and the "binder solids” are defined as follows. Binder component solids content - definition The content by weight of each of the components in a given binder solution before curing is based on the anhydrous mass of the components, i.e. without solvents, in particular water. The following formula can be used:

In case of calculating the binder component solids of dextrose only, the binder component A will be dextrose. In case of calculating the binder component solids content of a carbohydrate mixture in any of the given binders comprising carbohydrate, A can be e.g. dextrose and B can be e.g. fructose. In case of a PUF binder, formaldehyde and, if used, ammonia are also considered as components of the binder. While these starting materials are volatiles, they are reacted at least in part during the preparation of the PUF resin. Binder solids – definition and procedure The content by weight of binder after curing is termed “binder solids”. Disc-shaped stone wool samples (diameter: 5 cm; height 1 cm) were cut out of stone wool and heat-treated at 590 °C for at least 30 minutes to remove all organics. The solids of a binder were measured by distributing a sample of the binder (approx.2 g) onto a heat treated stone wool disc in a tin foil container. The tin foil container containing the stone wool disc was weighed before and directly after addition of the binder. Two such binder loaded stone wool discs in tin foil containers were produced and they were then heated for 1 h at 200 °C. After cooling and storing at room temperature for 10 minutes, the samples were weighed and the binder solids were calculated as an average of the two results and afterwards the binder solids content is expressed in weight percent. Reaction loss - definition The reaction loss is defined as the difference between the binder component solids content and the binder solids. Additives The aqueous binder composition of the present invention may further comprise one of more additives. The aqueous binder composition of the present invention may comprise one or more additives selected from a group of mineral oils, silicone and/or silane. Preferably the one or more additives may comprise silane, one or more hydrophobic agents such as silicone and/or one or more mineral oil(s). These additives may be hydrophobic components such as one or more reactive or non-reactive silicones and may be added to the binder composition. Preferably, the one or more silicone reactive or non-reactive silicone compounds is selected from the group consisting of silicone constituted of a main chain composed of organosiloxane residues, especially diphenylsiloxane residues, alkylsiloxane residues, preferably dimethylsiloxane residues, bearing at least one hydroxyl, carboxyl or anhydride, amine, epoxy or vinyl functional group capable of reacting with at least one of the constituents of the binder composition and is preferably present in an amount of 0.1-15 weight-%, preferably from 0.1-10 weight-%, more preferably 0.3-8 weight-%, based on the binder solids. The addition of silicones may be omitted if producing a hydrophilic mineral wool product such as horticultural growing media, mineral wool products for infiltration and water buffering or shock absorbing pads for sports fields, arenas or playgrounds. Hardeners, such as silanes, are preferably present in an amount of 0.01 to 5 % by weight, preferably from 0.05 to 1 % by weight, more preferably 0.1 to 0.8 % by weight, based on the binder solids. Preferably, the one or more silane is an amino- functional silane such as Dynasylan®HYDROSIL 1151 from Evonik Industries. As mentioned above, one or more mineral oil(s) may be added to the aqueous binder composition. The additives can be added before or after mixing of the final binder. A method of producing a mineral fibre product The present invention is also directed to a method of producing a bonded mineral fibre product which comprises the steps of contacting mineral fibres with an aqueous binder composition as described herein, and curing the binder. The aqueous binder composition has been described above. All indications discussed above for the aqueous binder composition of course also apply to the aqueous binder composition used in the method of the present invention. The mineral fibres employed may be for instance any of man-made vitreous fibres (MMVF), glass fibres or glass wool, ceramic fibres, basalt fibres, slag fibres, stone fibres or stone wool and others. The mineral fibres are preferably of the types generally known as rock, stone or slag fibres, most preferably stone fibres. These fibres may be present as a wool product, e.g. like a stone wool product. The man-made vitreous fibres can have any suitable oxide composition. In the below, the iron oxide may be a mixture of FeO and Fe2O3 but is quoted herein as Fe²O³. Stone fibres commonly comprise the following oxides, in percent by weight: SiO²: 30 to 51 Al²O³: 12 to 25 CaO: 8 to 30 MgO: 2 to 25 Fe2O3: 2 to 15 Na2O+K2O: not more than 10 CaO+MgO: 10 to 30 In preferred embodiments, the man-made vitreous fibres have the following levels of elements, calculated as oxides in wt%: SiO2: at least 30, 32, 35 or 37; not more than 51, 48, 45 or 43 Al2O3: at least 12, 16 or 17; not more than 30, 27 or 25 CaO: at least 8 or 10; not more than 30, 25 or 20 MgO: at least 2 or 5; not more than 25, 20 or 15 FeO (including Fe²O³): at least 4 or 5; not more than 15, 12 or 10 FeO+MgO: at least 10, 12 or 15; not more than 30, 25 or 20 Na²O+K²O: zero or at least 1; not more than 10 CaO+MgO: at least 10 or 15; not more than 30 or 25 TiO²: zero or at least 1; not more than 6, 4 or 2 TiO2+FeO: at least 4 or 6; not more than 18 or 12 B²O³: zero or at least 1; not more than 5 or 3 P²O⁵: zero or at least 1; not more than 8 or 5 Others: zero or at least 1; not more than 8 or 5 Glass fibres commonly comprise the following oxides, in percent by weight: SiO2 50 to 70 Al2O3 10 to 30 CaO not more than 27 MgO not more than 12 Glass fibres can also contain the following oxides, in percent by weight: Na²O+K²O 8 to 18, in particular Na²O+K²O greater than CaO+MgO, and B²O³ 3 to 12. Some glass fibre compositions can contain Al2O3 less than 2%. Man-made vitreous fibres can be made from a mineral melt. A mineral melt is provided in a conventional manner by providing mineral materials and melting them in a furnace. This furnace can be any of the types of furnaces known for production of mineral melts for man-made vitreouos fibres, for instance a shaft furnace such as a cupola furnace, a tank furnace, a submerged electrical furnace, or a cyclone furnace. Any suitable method may be employed to form man-made vitreous fibres from the mineral melt by fiberization. The fiberization can be by a spinning cup process in which melt is centrifugally extruded through orifices in the walls of a rotating cup (spinning cup, also known as internal centrifugation). Alternatively the fiberization can be by centrifugal fiberization by projecting the melt onto and spinning off the outer surface of one fiberizing rotor, or off a cascade of a plurality of fiberizing rotors, which rotate about a substantially horizontal axis (cascade spinner). The melt is thus formed into a cloud of fibres entrained in air and the fibres are collected as a web on a conveyor and carried away from the fiberizing apparatus. The web of fibres is then consolidated, which can involve cross-lapping and/or longitudinal compression and/or vertical compression and/or winding around a mandrel to produce a cylindrical product for pipe insulation. Other consolidation processes may also be performed. The step of contacting the mineral fibres with the aqueous binder composition can be effected by applying the aqueous binder composition on the mineral fibres with conventional means, for instance by spraying. The binder composition is applied to the fibres preferably when they are a cloud entrained in air. Alternatively, it can be applied after collection on the conveyor but this is less preferred. After consolidation the consolidated web of fibres is passed into a curing device to cure the binder. The curing process may commence immediately after application of the binder to the fibres. The curing is defined as a process whereby the binder composition undergoes a physical and/or chemical reaction which in case of a chemical reaction usually increases the molecular weight of the compounds in the binder composition and thereby increases the viscosity of the binder composition, usually until the binder composition reaches a solid state. The cured binder composition binds the fibres to form a structurally coherent matrix of fibres. In one embodiment the curing process comprises drying by pressure. The pressure may be applied by blowing air or gas through/over the mixture of mineral fibres and binder. In one embodiment the curing process comprises a drying process. In one embodiment the curing process comprises drying by pressure. The pressure may be applied by blowing air or gas to the mixture of mineral fibres and binder. The blowing process may be accompanied by heating or cooling or it may be at ambient temperature. In one embodiment, the curing takes place in a curing device such as in a conventional curing oven or a heat press. The curing of a binder composition in contact with the mineral fibres in a heat press has the particular advantage that it enables the production of high-density products. The curing of the aqueous binder composition which is in contact with the mineral fibres can be carried out within a wide temperature range. In one embodiment, the curing is carried out at temperatures from 180 to 360°C, preferably at temperatures from 200 to 275°C, more preferably at temperatures from 220 to 250°C. In one embodiment, the curing takes place for a time of 30 seconds to 20 minutes, such as 1 to 15 minutes, such as 2 to 10 minutes. In a typical embodiment, curing takes place at a temperature of 150 to 250 °C for a time of 30 seconds to 20 minutes. An additional advantage of the binders described herein is that they have a comparatively high curing speed at a low curing temperature. The higher curing speed of the binders described herein when compared to previously known carbohydrate binders allows the increase of the production capacity of a plant producing bonded mineral fibre products. At the same time, the low curing temperatures required for the binders described herein as compared to carbohydrate binders save energy in the production process and limit the emission of volatile compounds in the production process. In a preferred embodiment, the aqueous binder composition is applied in the close vicinity of the fibre forming apparatus, such as a cascade spinning apparatus or a cup spinning apparatus, in either case immediately after the fibre formation. Thus, the aqueous binder composition is preferably applied to the mineral fibres formed in the spinning chamber, preferably by spraying. The fibres with applied binder are thereafter usually conveyed onto a conveyor belt as a web, such as a collected web. The web, such as a collected web may be subjected to longitudinal or length compression after the fibre formation and before substantial curing has taken place. In a preferred embodiment, the method of producing a bonded mineral fibre product comprises the steps of: - making a melt of raw materials, - fiberizing the melt by means of a fibre forming apparatus to form mineral fibres, wherein the mineral fibers formed are preferably directed into a spinning chamber, - providing the mineral fibres in the form of a collected web, - applying the aqueous binder composition on the mineral fibres before, during or after the provision of the collected web to form a mixture of mineral fibres and binder composition, wherein the aqueous binder composition is preferably applied by spraying before the provision of the collected web, preferably in the spinning chamber, - curing the binder composition mixed with the mineral fibres. There are various types of centrifugal spinners used as a fibre forming apparatus for fiberizing mineral melts. A conventional centrifugal spinner is a cascade spinner which comprises a sequence of a top (or first) rotor and a subsequent (or second) rotor and optionally other subsequent rotors (such as third and fourth rotors). Each rotor rotates about a different substantially horizontal axis with a rotational direction opposite to the rotational direction of the or each adjacent rotor in the sequence. The different horizontal axes are arranged such that melt which is poured on to the top rotor is thrown in sequence on to the peripheral surface of the or each subsequent rotor, and fibres are thrown off the or each subsequent rotor, and optionally also off the top rotor. In one embodiment, a cascade spinner or other spinner is arranged to fiberize the melt and the fibres are entrained in air as a cloud of the fibres. Many fibre forming apparatuses comprise a disc or cup that spins around a substantially vertical axis. It is then conventional to arrange several of these spinners in-line, i.e. substantially in the first direction, for instance as described in GB-A-926,749, US-A-3,824,086 and WO-A-83/03092. There is usually a stream of air associated with the one or each fiberizing rotor whereby the fibres are entrained in this air as they are formed off the surface of the rotor. In one embodiment, the aqueous binder composition of the invention and/or additives are added to the cloud of fibres by known means. The amount of binder and/or additive may be the same for each spinner or it may be different. In one embodiment, the aqueous binder composition of the invention and/or additives are added to the cloud of fibres by known means. The amount of binder and/or additive may be the same for each spinner or it may be different. As used herein, the term "collected web" is intended to include any mineral fibres that have been collected together on a surface, i.e. they are no longer entrained in air, e.g. the fiberized mineral fibres, granulate, tufts or recycled web waste. The collected web could be a primary web that has been formed by collection of fibres on a conveyor belt and provided as a starting material without having been cross- lapped or otherwise consolidated. Alternatively, the collected web could be a secondary web that has been formed by cross-lapping or otherwise consolidating a primary web. Preferably, the collected web is a primary web. Mineral fibre product The present invention is also directed to a mineral fibre product comprising mineral fibres bound by a binder resulting from the curing of an aqueous binder composition of the invention. The mineral fibre product of the invention is preferably obtainable by the method according to the invention. The aqueous binder composition and the method have been described above. All indications discussed above for the aqueous binder composition and the method such as the mineral fibres also apply to the mineral fibre product of the present invention. In a preferred embodiment, the density of the mineral fibre product is in the range of 10-1200 kg/m³, such as 30-800 kg/m³, such as 40-600 kg/m³, such as 50-250 kg/m³, such as 60-200 kg/m³. In a preferred embodiment, the mineral fibre product as described herein is an insulation product, such as a thermal or acoustical insulation product, in particular having a density of 10 to 200 kg/m³. In an alternative embodiment, the mineral fibre product as described herein is a facade panel, in particular having a density of 1000-1200 kg/m³. In a preferred embodiment, the loss on ignition (LOI) of the mineral fiber product as described herein is within the range of 0.1 to 15.0 %, such as 0.3 to 10.0 %, such as 0.5 to 8.0 %, such as 0.7 to 6.0 % by weight. The mineral fibre product can be in any conventional configuration, for instance a mat or slab, and can be cut and/or shaped (e.g. into pipe sections) before, during or after curing of the binder. As can be seen from the experimental part below (Table 1-5), the accumulated formaldehyde emission from cured composite bars (simulating mineral wool products) is greatly reduced by using the aqueous binder mixture of PUF binder (component (I)) and carbohydrate binder (component (II)) when compared to a pure PUF binder. The accumulated formaldehyde emission of the cured composite bars bonded with the mixed aqueous binder as described herein is equal to or below 1 µg/g binder solids, preferably below 0.5 µg/g binder solids, for composite bars cured at 225°C. Even a low amount of the carbohydrate binder (component (II)) mixed with the PUF binder (component (I)) will result in a significant reduction of the accumulated formaldehyde emissions from the composite bars with cured mixed aqueous binder as described herein. A skilled person would expect that a mineral wool product bonded with a cured mixture of PUF binder (component (I)) and carbohydrate binder (component (II)) would result in a product formaldehyde emission which is reduced according to a linear regression, or in other words, a 10% reduction in formaldehyde emissions from a cured mineral wool product bonded with the aqueous binder as described herein is to be expected, where 10% PUF binder (component (I)) is replaced by 10% carbohydrate binder (component (II)). However, surprisingly it has been shown that the actual formaldehyde emission reduction demonstrated for cured composite bars being bonded by the inventive aqueous binder mixture is significantly larger than expected. Thus this aqueous mixed binder system seems to have a synergistic effect on lowering the formaldehyde emission from cured mineral wool products bonded with the inventive mixed aqueous binder as described herein. We obtain formaldehyde emissions from the cured composite bars bonded with the mixed PUF binder (component (I)) and carbohydrate binder (component (II)) which is being comparable (in the same order) to the formaldehyde free composite bars made with the commercial binder (C2). This indicates that we can obtain mineral wool products bonded with the cured inventive binder having formaldehyde emission values which can meet the standard for formaldehyde free mineral wool products (ISO 16000), even though we apply the inventive mixed aqueous PUF binder (component (I)) with carbohydrate binder (component (II)) as described herein to the mineral wool products. Applications The present invention is also directed to the use of an aqueous binder composition for the production of a mineral fibre product. The present invention is also directed to the use of an aqueous binder composition for lowering the formaldehyde and/or ammonia and/or phenol emissions during production of a mineral fibre product. The use is preferably carried out in a method as described above. The present invention is also directed to the use of an aqueous binder composition for lowering the formaldehyde emissions of a cured mineral fibre product. The use is preferably carried out in a method as described above. The present invention is also directed to a method of reducing the formaldehyde emission and/or the ammonia and/or phenol emission during application of a phenol-urea-formaldehyde binder (PUF binder) on mineral fibres in a spinning chamber, said method comprising the step of - adding a carbohydrate binder to the PUF binder to obtain an aqueous binder composition, wherein the carbohydrate binder comprises a component (a) in the form of one or more carbohydrates, and a component (b) in the form of: (bi) one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof, wherein component (a) is present in the aqueous binder composition in an amount of at least 20 % by weight based on the binder component solids, and - applying the resulting aqueous binder composition instead of the PUF binder on the mineral fibres, preferably in the spinning chamber. In a preferred embodiment, the method of reducing formaldehyde emission and/or ammonia and/or phenol emission during application of a phenol-urea- formaldehyde binder (PUF binder) on mineral fibres in a spinning chamber, said method comprising the step of - adding a carbohydrate binder to the PUF binder to obtain an aqueous binder composition, wherein the carbohydrate binder comprises a component (a) in the form of one or more carbohydrates, and a component (b) in the form of: (bi) one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof, and (bii) one or more compounds selected from hypophosphorous acid, derivatives of hypophosphorous acid or any salts thereof, wherein component (a) is present in the aqueous binder composition in an amount of at least 20 % by weight based on the binder component solids, and - applying the resulting aqueous binder composition instead of the PUF binder on the mineral fibres, preferably in the spinning chamber. The method of reducing the formaldehyde emission and/or the ammonia emission and /or phenol emission is preferably a method of producing a mineral fibre product as described herein. The aqueous binder composition, the method and the mineral fibre product have been described above. The present invention is also directed to a method of reducing the formaldehyde emission in a mineral fibre product. In particular, the present invention is directed to a method of reducing the formaldehyde emission in a mineral fibre product, prepared with a phenol-urea- formaldehyde binder (PUF binder), said method comprising the steps of - adding a carbohydrate binder to the PUF binder to obtain an aqueous binder composition, wherein the carbohydrate binder comprises a component (a) in the form of one or more carbohydrates, and a component (b) in the form of: (bi) one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof, and (bii) one or more compounds selected from hypophosphorous acid, derivatives of hypophosphorous acid or any salt thereof, wherein component (a) is present in the aqueous binder composition in an amount of at least 20 % by weight based on the binder component solids, - applying the resulting aqueous binder composition onto the mineral fibres, preferably in the spinning chamber, and - curing the aqueous binder composition. The method and the mineral fibre product have been described above. Examples In the following examples, several binders were prepared and compared to binders according to the prior art. Experimental methods and definitions General experimental methods 75 % aq. glucose syrup with a DE-value of 95 to less than 100 (C*sweet D 02767 ex Cargill) was supplied by Cargill. 40% silane (Momentive Silquest® VS-142, aminoalkylsilane hydrolyzate in water) was supplied by Momentive. 28% aq. ammonia, 50% aq. hypophosphorous acid, and all other components were obtained in high purity from Sigma-Aldrich or TCI. All components for which a concentration is not detailed above were assumed completely pure and anhydrous for simplicity. Measurements of pH were performed using a Mettler Toledo SevenCompactTM S220 pH meter equipped with a Mettler Toledo InLab® Expert Pro-ISM pH electrode and temperature probe. Crude stone shots (predominantly rounded particles which have the same melt composition as the stone wool fibers) formed during the cascade spinning process of a stone melt in the production of stone wool fibers were obtained from a ROCKWOOL factory in the Netherlands. Cleaned and sifted stone shots appropriate for the manufacture of composite bars were produced from these crude stone shots by ProChem GmbH, Germany. In brief, the stone shots were heat treated overnight at 590 °C to remove any trace organics. After cooling, the stone shots were sifted through 0.50 mm and 0.25 mm sieves. The coarse and fine fractions were discarded, and the remaining stone shots were washed thoroughly several times in demineralized water. The sifted and cleaned stone shots were dried and where then stored in a closed bag until use. In the following stone shots obtained are simply termed shots. FUNKTION heat resistant silicone forms for manufacture of bars (4×5 slots per form; slot top dimension: length = 5.6 cm, width = 2.5 cm; slot bottom dimension: length = 5.3 cm, width = 2.2 cm; slot height = 1.1 cm) were obtained from F&H of Scandinavia A/S. Three-point bending tests were recorded on a Bent Tram SUT 3000/520 test machine (test speed: 10.0 mm/min; rupture level: 50 N; nominal strength: 30 N/mm2; support distance: 40 mm; max deflection 20 mm; nominal E-modulus 10000 N/mm2). The bars were placed with the “top face” up (i.e. the face with the dimensions length = 5.6 cm, width = 2.5 cm) in the machine. New tin foil containers for use in measurement of binder solids and of loss of ignition of composite bars were heat-treated at 590 °C for 15 minutes prior to use to remove all organics. An open-end, heated tube oven apparatus was used for the generation of simulated spinning chamber emissions. The emissions generated from binder samples placed within the tube oven at a given temperature were measured by drawing a constant flow of air across the sample through heated tubes to a MKS 2030 FTIR gas analyzer. Series 2000 Multigas Analyzer software (version 10.4) was used to analyze the spectral data. An Agilent 1260 HPLC with Infinity mass spectrometer equipped with a Zorbax SB C-18 column (2.1x50 mm, 1.8 micron, P.N 827700-902) and a Zorbax SB C- 18 guard column (4.6x5 mm, 1.8 micron, P.N 820750-902) was used to analyze samples for measurements of accumulated formaldehyde emissions, using as solvent A: H2O (0.1% formic acid) and solvent B: acetonitrile. Gradient: 65% A (0- 1 min), 65%→20% A (1-9 min), 20%→65% A (9-11 min). Steel sample holders (which can hold a volume slightly larger than the composite bars) for suspending the samples over a DNPH solution in 100 mL blue cap bottles were heat-treated at 590 °C for 15 minutes prior to use to remove all organics. Binder component solids content – definition The content by weight of each of the components in a given binder solution before curing is based on the anhydrous mass of the components, i.e. without solvents, in particular water. The following formula can be used: ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ( ^^) + ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ( ^^) + ⋯ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ (%) = ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ℎ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ( ^^) ^{× 100%} In case of calculating the binder component solids of dextrose only, the binder component A will be dextrose. In case of calculating the binder component solids content of a carbohydrate mixture in any of the given binders comprising carbohydrate, A can be e.g. dextrose and B can be e.g. fructose. In case of a PUF binder, for example, formaldehyde and ammonia are also considered as components of the binder. While these starting materials are volatiles, they are reacted at least in part during the preparation of the PUF resin. Binder solids – definition and procedure The content of binder after curing is termed “binder solids”. Disc-shaped stone wool samples (diameter: 5 cm; height 1 cm) were cut out of stone wool and heat-treated at 590 °C for at least 30 minutes to remove all organics. The solids of the binder mixture (see below for mixing examples) were measured by distributing a sample of the binder mixture (approx.2 g) onto a heat treated stone wool disc in a tin foil container. The tin foil container containing the stone wool disc was weighed before and directly after addition of the binder mixture. Two such binder mixture loaded stone wool discs in tin foil containers were produced and they were then heated for 1 h at 200 °C (comparative binder A), 1 h at 225 °C (comparative binder A, comparative binder B and comparative binders C) or 2 h at 225 °C (comparative binder B and comparative binders C). After cooling and storing at room temperature for 10 minutes, the samples were weighed and the binder solids were calculated as an average of the two results, and afterwards the binder solids content is expressed in weight percent. Reaction loss - definition The reaction loss is defined as the difference between the binder component solids content and the binder solids. Manufacture of composite bars (comparative binders A, B and C) A 17.5% binder solids solution was obtained as described in the examples below. A sample of the binder solution (70.1 g) was added to shots (460.0 g) in a mixing bowl at room temperature. The resulting mixture was then mixed for approx.2-5 minutes using a mixing machine. The resulting mixture was then filled into 16 slots in a heat resistant silicone form for making bars. During the manufacture of each composite bar, the mixtures placed in the slots were pressed as required and then evened out with a plastic spatula to generate an even bar surface. Composite bars made using comparative binder A were cured for 1 h at 200 °C or 225 °C, while composite bars made using comparative binder B or comparative binders C were cured for 2 h at 225 °C, while bars made with comparative binders D were cured for 1 h at 200 °C or 225 °C. After cooling to room temperature, the composite bars were stored in a climate chamber at 22 °C / 50% rh. Manufacture of composite bars (comparative binders D) A 17.5% binder mixture comprising comparative binder A : comparative binder B in proportions of 75:25, 50:50 or 25:75 was obtained as described in the examples below. A sample of the binder mixture (70.1 g) was added to shots (460.0 g) in a mixing bowl at room temperature. The resulting mixture was then mixed for approx.2-5 minutes using a mixing machine. The resulting mixture was then filled into 16 slots in a heat resistant silicone form for making bars. During the manufacture of each composite bar, the mixtures placed in the slots were pressed as required and then evened out with a plastic spatula to generate an even bar surface. Bars made using binder mixtures comprising comparative binder A : comparative binder B in a proportion of 75:25 were cured for 1 h at 200 °C, while bars made using binder mixtures comprising comparative binder A : comparative binder B in proportions of 50:50 or 25:75 were cured for 1 h at 225 °C. After cooling to room temperature, the composite bars were stored in a climate chamber at 22 °C / 50% rh. Manufacture of composite bars (binder compositions as described herein) A 17.5% binder mixture comprising comparative binder A : comparative binder C in proportions of 75:25, 50:50, 25:75 or 10:90 was obtained as described in the examples below. A sample of the binder mixture (70.1 g) was added to shots (460.0 g) in a mixing bowl at room temperature. The resulting mixture was then mixed for approx.2-5 minutes using a mixing machine. The resulting mixture was then filled into 16 slots in a heat resistant silicone form for making bars. During the manufacture of each composite bar, the mixtures placed in the slots were pressed as required and then evened out with a plastic spatula to generate an even bar surface. Bars made using binder mixtures comprising comparative binder A : comparative binder C in a proportion of 75:25 were cured for 1 h at 200 °C or 225°C, while bars made using binder mixtures comprising comparative binder A : comparative binder C in proportions of 50:50 or 25:75 were cured for 1 h at 225 °C. Bars made using binder mixtures comprising comparative binder A : comparative binder C in a proportion of 10:90 were cured for 2 h at 225 °C. After cooling to room temperature, the composite bars were stored in a climate chamber at 22 °C / 50% rh. Ageing treatment of composite bars Ageing treatment of composite bars was performed by subjecting the bars to autoclave treatment (15 min / 120 °C / 1.2 bar) or water bath treatment (3 h / 80 °C) followed by cooling to room temperature. After initial drying at ambient conditions for one day, the composite bars were stored in a climate chamber at 22 °C / 50% rh. Measurement of mechanical strengths of composite bars The maximum load force required to break composite bars was recorded in a three-point bending test. For each data point, an average value was calculated on the basis of four bars that had been subjected to identical treatment. The composite bars were stored in a climate chamber at 22 °C / 50% rh for at least three days prior to measuring the maximum load force. Measurement of loss of ignition (LOI) of composite bars The loss of ignition (LOI) of the composite bars was measured in small tin foil containers by treatment at 590 °C. The tin foil container was weighed and four bars (usually after being broken in the three-point bending test) were placed into the tin foil container. The ensemble was weighed and was then heat-treated at 590 °C for 30 minutes. After cooling to room temperature, the weight was recorded again and the loss of ignition (LOI) was calculated using the following formula:

Water absorption measurements The water absorption of the binders was measured by weighing three bars and then submerging the bars in water (approx.250 mL) in a beaker (565 mL, bottom Ø = 9.5 cm; top Ø = 10.5 cm; height = 7.5 cm) for 24 h. The bars were placed next to each other on the bottom of the beaker with the “top face” down (i.e. the face with the dimensions length = 5.6 cm, width = 2.5 cm). After the designated amount of time, the bars were lifted up one by one and allowed to drip off for one minute. The bars were held (gently) with the length side almost vertical so that the droplets would drip from a corner of the bar. The bars were then weighed and the water absorption was calculated using the following formula: ^^ ^^ ^^ ^^ℎ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ( ^^) − ^^ ^^ ^^ ^^ℎ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ( ^^) ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^. (%) = ^^ ^^ ^^ ^^ℎ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ( ^^) ^{× 100%} Curing characteristics – DMA (dynamic mechanical analysis) measurements A 17.5% binder solids binder solution was obtained as described above. Cut and weighed glass Whatman™ glass microfiber fi lters (GF/B, 150 mm Ø, cat. no. 1821150) (2.5×1 cm) were submerged into the 17.5% binder solution for 10 seconds. The resulting binder-soaked fi lter was then dried in a “sandwich” consisting of (1) a 0.60 kg 8×8×1 cm metal plate, (2) four layers of standard fi lter papers, (3) the binder soaked glass microfiber fi lter, (4) four layers of standard fi lter papers, and (5) a 0.60 kg 8 ×8×1 cm metal plate for approximately 2×2 minutes by applying a weight of 3.21 kg on top of the “sandwich”. In a typical experiment, the cut Whatman™ glass microfiber fi lter would weigh 0.035 g before application of the binder and 0.125 g after application and drying. The DMA measurements were acquired on a Mettler Toledo DMA 1 calibrated against a certi fied thermometer at ambient temperature and the melting points of certi fied indium and tin. The apparatus was operated in single canti lever bending mode; ti tanium clamps; clamp distance 1.0 cm; temperature segment type; temperature range 40 -280 °C; heating rate 3 °C / min; displacement 20 μm; frequency 1 Hz; single frequency osci llation mode. Curing onset and endset were evaluated using STARe software Version 12.00. Measurements of simulated spinning chamber emissions of ammonia and formaldehyde A 17.5% binder mixture was obtained in an analogous manner to the procedures described in the examples below. Immediately prior to commencing each emission measurement, approximately 0.70 g of the binder mixture was distributed evenly on binder-free stone wool samples in a small ceramic crucible. Background ammonia and formaldehyde emissions were obtained by starting the emission measurements in the oven heated to 95 °C a few minutes before inserting the sample. The sample was then loaded into the tube oven and a temperature probe was inserted close to the sample to measure the actual temperature. Gas phase emissions IR spectra were then recorded with a 5 second sample frequency during a period of about 1 hour at 95 °C. The recorded individual ammonia and formaldehyde concentration time series obtained from the start of the measurement to the disappearance of the signal from water evaporation (generally about 40 minutes) were integrated to yield the simulated spinning chamber emissions of ammonia, formaldehyde and phenol. Three measurements were performed for each binder composition and the emission results were averaged. The results are given in Table 1-1, 1-2, 1-3 and 1-4 as relative emission indexes compared to comparative binder A (index 100). Measurement of accumulated formaldehyde emissions from cured binders Accumulated formaldehyde emissions from cured composite bars were determined by HPLC-MS of dinitrophenyl hydrazine (DNPH) derivatized formaldehyde. The detection was made by mass spectrometry. The specific mass of DNPH formaldehyde 209 m/z was monitored in selected ion monitoring mode and measured. The composite bars, i.e. one whole bar, was placed in the holder after noting the weight of the bar. The samples were then placed in 100 mL blue cap bottles containing 10 mL DNPH solution (obtained from 400 mg dinitrophenyl hydrazine, 50 mg conc. sulfuric acid, and acetonitrile to 1000 mL total volume). The bottles were closed tightly and sealed with parafilm. Enough such samples were produced to allow for three measurements after 7 days, 14 days and 28 days (thus nine samples in total per binder). The setup also comprised blanks that served to obtain background measurements which were deducted from the actual sample measurements. After the designated amount of time, 1.00 mL of the DNPH solution was collected and passed through a 0.22 µ syringe filter. The samples were then analyzed by HPLC (each sample was determined twice) and the amount of formaldehyde captured was determined using a calibration curve obtained from an aldehyde/ketone DNPH stock standard-13 (Sigma-Aldrich ERA028) in acetonitrile. The data was converted into µg formaldehyde / g binder solids using the measured sample weights in combination with loss on ignition measurements obtained on unused composite bars. The measurements are given in the Table 1-5 in absolute numbers. Comparative binder compositions from the prior art Comparative binder A (phenol-formaldehyde resin modified with urea, a PUF- resol) A phenol-formaldehyde resin is prepared by reacting 37% aq. formaldehyde (606 g) and phenol (189 g) in the presence of 46% aq. potassium hydroxide (25.5 g) at a reaction temperature of 84°C preceded by a heating rate of approximately 1°C per minute. The reaction is continued at 84 °C until the acid tolerance of the resin is 4 and most of the phenol is converted. Urea (241 g) is then added and the mixture is cooled. The acid tolerance (AT) expresses the number of times a given volume of a binder can be diluted with acid without the mixture becoming cloudy (the binder precipitates). Sulfuric acid is used to determine the stop criterion in a binder production and an acid tolerance lower than 4 indicates the end of the binder reaction. To measure the AT, a titrant is produced from diluting 2.5 ML conc. sulfuric acid (>99 %) with 1 L ion exchanged water. 5 mL of the binder to be investigated is then titrated at room temperature with this titrant while keeping the binder in motion by manually shaking it; if preferred, use a magnetic stirrer and a magnetic stick. Titration is continued until a slight cloud appears in the binder, which does not disappear when the binder is shaken. The acid tolerance (AT) is calculated by dividing the amount of acid used for the titration (mL) with the amount of sample (mL): AT = (Used titration volume (mL)) / (Sample volume (mL)) Using a portion of the urea-modified phenol-formaldehyde resin obtained (100.0 g), a binder is made by addition of 28% aq. ammonia (7.47 g) and ammonium sulfate (1.20 g) followed by water (100.9 g). The binder solids were then measured as described above: 22.0% for 1 h at 200 °C (thus 30.2% reaction loss); 21.1% for 1 h at 225 °C (thus 33.0% reaction loss). The mixture was then diluted with the required amount of water and 4% Momentive VS-142 silane (17.5% final binder solids solution, 0.2% silane of binder solids; final pH 9.6). Comparative binder B (carbohydrate binder) A mixture of 75% aq. glucose syrup (130.0 g) in water (133.5 g) was stirred at room temperature unti l a clear solution was obtained (pH 3.9). The binder solids were measured as described above: 22.2% for 1 h at 225 °C (thus 40.0% reaction loss); 21.2% for 2 h at 225 °C (thus 42.7% reaction loss). The mixture was then di luted with the required amount of water and 4% Momentive VS-142 si lane (17.5% final binder solids solution, 0.2% si lane of binder solids; final pH 8.5-9.2). Comparative binders C (carbohydrate binder), example C1 A mixture of 75% aq. glucose syrup (86.6 g), ammonium sulfamate (3.25 g) and urea (3.25 g) in water (151.8 g) was stirred at room temperature unti l a clear solution was obtained.28% aq. ammonia (0.05 g) was then added dropwise to pH 7.2. The binder solids were measured as described above: 19.0% for 1 h at 225 °C (thus 34.9% reaction loss); 17.8% for 2 h at 225 °C (thus 39.0% reaction loss). The mixture was then di luted with the required amount of water and 4% Momentive VS -142 si lane (17.5% final binder solids solution, 0.2% si lane of binder solids; final pH 7.0-7.2). Comparative binders C (carbohydrate binder), example C2 A mixture of 75% aq. glucose syrup (173.2 g), ammonium sulfamate (5.20 g), 50% aq. hypophosphorous acid (2.60 g) and urea (6.50 g) in water (303.5 g) was stirred at room temperature until a clear solution was obtained.28% aq. ammonia (1.81 g) was then added dropwise to pH 7.3. The binder solids were measured as described above: 18.8% for 1 h at 225 °C (thus 35.4% reaction loss); 17.9% for 2 h at 225 °C (thus 38.5% reaction loss). The mixture was then diluted with the required amount of water and 4% Momentive VS-142 silane (17.5% final binder solids solution, 0.2% silane of binder solids; final pH 7.2). Comparative binder C, example C2, corresponds to the commercial binder described in WO2016/102444. Comparative binders C (carbohydrate binder), example C3 A mixture of 75% aq. glucose syrup (86.6 g), ammonium sulfamate (1.30 g), 50% aq. hypophosphorous acid (2.60 g) and urea (3.25 g) in water (151.8 g) was stirred at room temperature until a clear solution was obtained.28% aq. ammonia (1.90 g) was then added dropwise to pH 7.9. The binder solids were measured as described above: 18.6% for 1 h at 225 °C (thus 35.5% reaction loss); 18.0% for 2 h at 225 °C (thus 37.6% reaction loss). The mixture was then diluted with the required amount of water and 4% Momentive VS-142 silane (17.5% final binder solids solution, 0.2% silane of binder solids; final pH 7.7-7.9). Comparative binders C (carbohydrate binder), example C4 A mixture of 75% aq. glucose syrup (86.6 g), aq. 50% hypophosphorous acid (3.90 g) and urea (3.25 g) in water (151.8 g) was stirred at room temperature unti l a clear solution was obtained. 28% aq. ammonia (3.07 g) was then added dropwise to pH 7.2. The binder solids were measured as described above: 18.3% for 1 h at 225 °C (thus 35.9% reaction loss); 17.3% for 2 h at 225 °C (thus 39.4% reaction loss). The mixture was then diluted with the required amount of water and 4% Momentive VS-142 silane (17.5% final binder solids solution, 0.2% silane of binder solids; final pH 6.6-7.2). Comparative binders D (binder mixtures with comparative binder A : comparative binder B proportions of 75:25, 50:50 or 25:75), examples D1-D3 To comparative binder A (17.5% binder solids measured at 225 °C / 1 h) stirred at room temperature was added comparative binder B (17.5% binder solids measured at 225 °C / 1 h). The comparative binders were mixed in in the desired proportions (A:B 75:25, 50:50 or 25:75) on a scale resulting in 80 g final binder mixture. After stirring for 1-2 minutes further, the resulting mixtures (pH 9.1-9.4) were used in the subsequent experiments. Binder compositions as described herein General binder example (binder mixtures with comparative binder A : comparative binder C proportions of 75:25, 50:50, 25:75 or 10:90), examples 1-7 To comparative binder A (17.5% binder solids measured at 225 °C / 1 h) stirred at room temperature was added comparative binder C (17.5% binder solids measured at 225 °C / 1 h). The comparative binders were mixed in in the desired proportions (A:C 75:25, 50:50, 25:75 or 10:90) on a scale resulting in 80 g final binder mixture. After stirring for 1-2 minutes further, the resulting mixtures (pH 8.7- 9.7) were used in the subsequent experiments. The compositions of the comparative binders and the inventive binders as well as the results achieved by the test procedures are shown in the following Tables 1-1 to 1-4. The cured compositions of the comparative binders and the inventive binders as well as the results achieved by the test procedures are shown in the following Table 1-5. TABLE 1-1: Binder compositions according to the prior art Example A B C1 C2 C3 C4 Binder composition Binder component solids Formaldehyde 32.0 - - - - - Phenol 27.0 - - - - - Potassium hydroxide 1.7 - - - - - Urea 34.4 - - - - - Ammonia 3.2 - - - - - Ammonium sulfate 1.8 - - - - - Glucose syrup - 100.0 90.9 90.6 91.1 91.5 Ammonium sulfamate - - 4.5 3.6 1.8 - Hypophosphorous acid - - - 0.9 1.8 2.7 Urea - - 4.5 4.5 4.6 4.6 Ammonia - - 0.02 0.4 0.7 1.2 Other additives ^[a] Silane 0.2 0.2 0.2 0.2 0.2 0.2 Binder properties pH of binder mixture 9.6 8.5-9.2 7.0-7.2 7.2-7.3 7.7-7.9 6.6-7.2 Reaction loss, 1h / 200C (%) 30.2 - - - - - Reaction loss, 1h / 225C (%) 33.0 40.0 34.9 35.4 35.5 35.9 Reaction loss, 2h / 225C (%) - 42.7 39.0 38.5 37.5 39.4 Curing onset (°C) 155 - - 165 - - Curing endset (°C) 172 - - 185 - - Binder mixing and bar manufacture Binder solids (%) 17.5 17.5 17.5 17.5 17.5 17.5 Curing time (h) and temperature (°C) 1/200 2/225 2/225 2/225 2/225 2/225 Bar properties Mechanical strength, unaged (kN) 0.55 0.30 - 0.42 - - Mechanical strength, AC aged (kN) 0.19 0.08 - 0.16 - - Mechanical strength, WB aged (kN) 0.19 0.07 - 0.16 - - LOI, unaged (%) 2.58 2.61 - 2.56 - - Bar weight (g per bar) 25.3 23.8 - 24.3 - - Water absorption, 24 h (%) 10 18 - 25 - - Simulated spinning chamber emissions Relative ammonia emission index 100 - - 2 - - Relative formaldehyde emission 100 - - 0 - - index Rela [^a]tive phenol emission index 100 - - 0 - - Of binder solids. TABLE 1-2: Binder compositions according to the prior art using comparative binders A and B Example A D1 D2 D3 B Binder composition Binder composition ^[a] A 100 75 50 25 - B - 25 50 75 100 C1 - - - - - C2 - - - - - C3 - - - - - C4 - - - - - Binder component solids Formaldehyde 32.0 23.3 15.1 7.4 - Phenol 27.0 19.7 12.7 6.2 - Potassium hydroxide 1.7 1.2 0.8 0.4 - Urea 34.4 25.1 16.2 7.9 - Ammonia 3.2 2.3 1.5 0.7 - Ammonium sulfate 1.8 1.3 0.9 0.4 - Glucose syrup - 27.1 52.7 77.0 100.0 Ammonium sulfamate - - - - - Hypophosphorous acid - - - - - Urea - - - - - Ammonia - - - - - Other additives ^[b] Silane 0.2 0.2 0.2 0.2 0.2 Binder properties pH of binder mixture 9.6 9.4 9.3 9.1 8.5-9.2 Reaction loss, 1h / 200C (%) 30.2 - - - - Reaction loss, 1h / 225C (%) 33.0 - - - 40.0 Reaction loss, 2h / 225C (%) - - - - 42.7 Curing onset (°C) 155 - 165 - 221 Curing endset (°C) 172 - 186 - 239 Binder mixing and bar manufacture Binder solids (%) 17.5 17.5 17.5 17.5 17.5 Curing time (h) and temperature (°C) 1/200 1/200 1/225 1/225 2/225 Bar properties Mechanical strength, unaged (kN) 0.55 0.42 0.45 0.39 0.30 Mechanical strength, AC aged (kN) 0.19 0.19 0.18 0.15 0.08 Mechanical strength, WB aged (kN) 0.19 0.15 0.20 0.14 0.07 LOI, unaged (%) 2.58 2.66 2.67 2.66 2.61 Bar weight (g per bar) 25.3 25.4 25.3 25.3 23.8 Water absorption, 24 h (%) 10 20 21 18 18 Simulated spinning chamber emissions Relative ammonia emission index 100 - 65 - - Relative formaldehyde emission index 100 - 89 - - Rela [^a]tive phenol emission index lids measured at 225 °C for 1 h. ^[ 100 - 51 - - Binder so ^b] Of binder solids. TABLE 1-3: Binder mixtures obtained using comparative binders A and C2 Example A 1 2 D2 3 D3 4 C2 Binder composition Binder composition ^[a] A 100 75 50 50 25 25 10 - B - - - 50 - 75 - - C1 - - - - - - - - C2 - 25 50 - 75 - 90 100 C3 - - - - - - - - C4 - - - - - - - - Binder component solids Formaldehyde 32.0 23.8 15.7 15.1 6.8 7.4 3.1 - Phenol 27.0 20.0 13.2 12.7 6.6 6.2 2.6 - Potassium hydroxide 1.7 1.2 0.8 0.8 0.4 0.4 0.2 - Urea 34.4 25.6 16.9 16.2 8.4 7.9 3.3 - Ammonia 3.2 2.4 1.6 1.5 0.8 0.7 0.3 - Ammonium sulfate 1.8 1.4 0.9 0.9 0.4 0.4 0.2 - Glucose syrup - 23.3 46.1 52.7 68.5 77.0 81.8 90.6 Ammonium sulfamate - 0.9 1.8 - 2.7 - 3.3 3.6 Hypophosphorous acid - 0.2 0.5 - 0.7 - 0.8 0.9 Urea - 1.2 2.3 - 3.4 - 4.1 4.5 Ammonia - 0.1 0.2 - 0.3 - 0.3 0.4 Other additives ^[b] Silane 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Binder properties pH of binder mixture 9.6 9.7 9.4-9.6 9.3 9.1-9.2 9.1 9.0 7.2-7.3 Reaction loss, 1h / 30.2 - - - - - - - 200C (%) Reaction loss, 1h / 33.0 - - - - - - 35.4 225C (%) Reaction loss, 2h / - - - - - - - 38.5 225C (%) Curing onset (°C) 155 152 153 165 159 - - 165 Curing endset (°C) 172 170 176 186 185 - - 185 Binder mixing and bar manufacture Binder solids (%) 17.5 17.5 17.5 17.5 17.5 17.5 17.5 17.5 Curing time (h) and 1/200 1/200 1/225 1/225 1/225 1/225 2/225 2/225 temperature (°C) Bar properties Mechanical strength, 0.55 0.53 0.48 0.45 0.48 0.39 0.58 0.42 unaged (kN) Mechanical strength, 0.19 0.22 0.22 0.18 0.21 0.15 0.21 0.16 AC aged (kN) Mechanical strength, 0.19 0.21 0.26 0.20 0.25 0.14 0.16 0.16 WB aged (kN) LOI, unaged (%) 2.58 2.61 2.50 2.67 2.54 2.66 2.54 2.56 Bar weight (g per bar) 25.3 25.6 24.9 25.3 25.5 25.3 25.9 24.3 Water absorption, 24 h 10 20 20 21 22 18 22 25 (%) Simulated spinning chamber emissions Relative ammonia 100 73 50 65 26 - - 2 emission index Relative formaldehyde 100 7 6 89 5 - - 0 emission index Relative phenol 100 30 24 51 11 - - 0 e ^[am ] ission index Binder solids measured at 225 °C for 1 h. ^[b] Of binder solids.

TABLE 1-4: Binder mixtures obtained

binders A and

Example A 5 2 6 7 C2 Binder composition Binder composition ^[a] A 100 50 50 50 50 - B - - - - - - C1 - 50 - - - - C2 - - 50 - - 100 C3 - - - 50 - - C4 - - - - 50 - Binder component solids Formaldehyde 32.0 15.8 15.7 15.7 15.6 - Phenol 27.0 13.3 13.2 13.2 13.2 - Potassium hydroxide 1.7 0.8 0.8 0.8 0.8 - Urea 34.4 17.0 16.9 16.9 16.8 - Ammonia 3.2 1.6 1.6 1.6 1.5 - Ammonium sulfate 1.8 0.9 0.9 0.9 0.9 - Glucose syrup - 46.1 46.1 46.4 46.7 90.6 Ammonium sulfamate - 2.3 1.8 0.9 - 3.6 Hypophosphorous acid - - 0.5 0.9 1.4 0.9 Urea - 2.3 2.3 2.3 2.3 4.5 Ammonia - 0.01 0.2 0.4 0.6 0.4 Other additives ^[b] Silane 0.2 0.2 0.2 0.2 0.2 0.2 Binder properties pH of binder mixture 9.6 9.3 9.3-9.6 9.3 9.2 7.2-7.3 Reaction loss, 1h / 200C (%) 30.2 - - - - - Reaction loss, 1h / 225C (%) 33.0 - - - - 35.4 Reaction loss, 2h / 225C (%) - - - - - 38.5 Curing onset (°C) 155 157 153 154 155 165 Curing endset (°C) 172 182 176 176 176 185 Binder mixing and bar manufacture Binder solids (%) 17.5 17.5 17.5 17.5 17.5 17.5 Curing time (h) and temperature (°C) 1/200 1/225 1/225 1/225 1/225 2/225 Bar properties Mechanical strength, unaged (kN) 0.55 0.42 0.47 0.49 0.45 0.42 Mechanical strength, AC aged (kN) 0.19 0.12 0.22 0.18 0.18 0.16 Mechanical strength, WB aged (kN) 0.19 0.13 0.26 0.20 0.17 0.16 LOI, unaged (%) 2.58 2.60 2.50 2.58 2.53 2.56 Bar weight (g per bar) 25.3 25.5 24.9 27.1 25.7 24.3 Water absorption, 24 h (%) 10 22 20 20 21 25 Simulated spinning chamber emissions Relative ammonia emission index 100 - 50 - - 2 Relative formaldehyde emission 100 - 6 - - 0 index Relative phenol emission index 100 - 24 - - 0 ^[a] Binder solids measured at 225 °C for 1 h. ^[b] Of binder solids. TABLE 1-5: Formaldehyde emissions from cured composite bars obtained using mixtures of comparative binders A and C2 Example A 1 2 3 C2 Binder composition Binder composition ^[a] A 100 75 50 25 - C₂ - 25 50 75 100 Binder mixing and bar manufacture B_{inder solids (%)} ^{17.5 17.5 17.5 17.5 17.5} Curing time (h) and temp. (°C) 1/225 1/225 1/225 1/225 2/225 Accumulated formaldehyde emissions D_{ay 7 (µg/g binder solids)} ^{4.0 0.6 0.2 0.4 0.3} D_{ay 14 (µg/g binder solids)} ^{6.5 0.6 0.2 0.5 0.5} D_{ay 28 (µg/g binder solids)} ^{9.5 0.6 0.2 0.5 0.9} Binder solids measured at 225 °C for 1 h.

Items Item 1. An aqueous binder composition for mineral fibres made of a mixture of I) a phenol-urea-formaldehyde binder (PUF binder), and II) a carbohydrate binder comprising: a component (a) in the form of one or more carbohydrates; a component (b) in the form of: (bi) one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof, or (bii) one or more compounds selected from hypophosphorous acid, derivatives of hypophosphorous acid or any salt thereof, or (biii) a mixture of (bi) and (bii), wherein component (a) is present in an amount of at least 20 % by weight based on the binder component solids. Item 1a.) An aqueous binder composition for mineral fibres made of a mixture of I) a phenol-urea-formaldehyde binder (PUF binder), and II) a carbohydrate binder comprising: a component (a) in the form of one or more carbohydrates; a component (b) in the form of: (bii) one or more compounds selected from hypophosphorous acid, derivatives of hypophosphorous acid or any salt thereof, wherein component (a) is present in an amount of at least 20 % by weight based on the binder component solids. Item 2. The aqueous binder composition according to item 1 or 1a.), wherein the PUF binder and the carbohydrate binder are mixed in a ratio such that the proportion by weight B, based on the combined weight of A+B, is in the range of 20 to 95% by weight, wherein B is the weight of the binder solids of the carbohydrate binder and A is the weight of the binder solids of the PUF binder. Item 3. The aqueous binder composition according to item 2, wherein the proportion by weight B, based on the combined weight of A+B, is in the range of 25 to 90%. Item 4. The aqueous binder composition according to item 2 or 3, wherein the proportion by weight A, based on the combined weight of A+B, is in the range of 5 to 50% by weight, preferably 10 to 45% by weight, more preferably 20 to 40 % by weight, or wherein the proportion by weight B, based on the combined weight of A+B, is in the range of 50 to 95% by weight, preferably 55 to 90% by weight, more preferably 60 to 80% by weight. Item 5. The aqueous binder composition according to any of the preceding items, wherein the PUF binder (component (I)) is a phenol-urea- formaldehyde resole binder. Item 6. The aqueous binder composition according to any of the preceding items, wherein with respect to the starting materials phenol, formaldehyde and urea for preparing the PUF binder the molar ratio of phenol to formaldehyde is from 1:2.5 to 1:6; preferably from 1:3 to 1:5, and/or the amount of urea is from 20 to 60% by weight, preferably 30 to 50% by weight, based on total weight of phenol, formaldehyde and urea. Item 7. The aqueous binder composition according to any of the preceding items, wherein the PUF binder is modified with ammonia or is not modified with ammonia, wherein the amount of ammonia is preferably 0 to 6% by weight, more preferably 0 to 4% by weight, more preferably 0 to 3% by weight of the PUF binder component solids. Item 8. The aqueous binder composition according to any of the preceding items, wherein the PUF binder is modified with ammonia, wherein the amount of ammonia is preferably 0.1 to 6% by weight, more preferably 0.5 to 4% by weight, most preferably 1 to 3% by weight of the PUF binder component solids. Item 9. An aqueous binder composition according to any of the preceding items, wherein component (a) is one or more carbohydrates having a DE value of 60 to 100, in particular 85 to 100, more particular 95 to 100. Item 10. An aqueous binder composition according to any preceding items, wherein the component (a) is a glucose syrup having a DE of 60 to 100, in particular of 85 to 100, more particular 95 to 99. Item 11. An aqueous binder composition according to any of the preceding items, wherein the component (a) is dextrose having a DE of 85 to 100. Item 12. An aqueous binder composition according to any of the preceding items, wherein the component (a) is a hexose, such as fructose, and/or a pentose such as xylose. Item 13. An aqueous binder composition according to any of the preceding items wherein component (a) is present in an amount of at least 20% to 90% by weight of binder component solids, more preferably 40 to 90 % by weight of binder component solids, most preferably 60 to 80% by weight of binder component solids. Item 14. An aqueous binder composition according to any of the preceding items, wherein component (bi) is selected from the group consisting of sulfamic acid and any salt thereof, such as ammonium sulfamate, calcium sulfamate, sodium sulfamate, potassium sulfamate, magnesium sulfamate, cobalt sulfamate, nickel sulfamate, N-cyclohexyl sulfamic acid and any salt thereof, such as sodium N-cyclohexyl sulfamate. Item 15. An aqueous binder composition according to any of the preceding items, wherein the component (bii) is selected from the group consisting of hypophosphorous acid and any salt thereof, such as ammonium hypophosphite or sodium hypophosphite. Item 16. An aqueous binder composition according to any of the preceding items, wherein the mass ratio of component (bi) to component (bii) is preferably ≥1:1, more preferably between 3:1 to 5:1, most preferably 4:1. Item 17. An aqueous binder composition according to any one of the preceding items wherein the proportion of component (b) is within the range of 1 to 15 wt%, in particular 1-12 wt%, more particular 2-10 wt% based on binder component solids. Item 18. An aqueous binder composition according to any of the preceding items, wherein the carbohydrate binder (component (II)) further comprises a component (c) in the form of ammonia, wherein the amount of ammonia is preferably 0.01 to 2 % by weight, more preferably 0.01 to 1 % by weight based on binder component solids. Item 19. An aqueous binder composition according to any of the preceding items, wherein the carbohydrate binder (component (II)) further comprises a component (d) in the form of urea, wherein the amount of urea is preferably 0.5 to 6 % by weight, more preferably 1 to 5 % by weight, more preferably 2 to 4 % by weight based on binder component solids. Item 20. An aqueous binder composition according to any one of the preceding items, wherein the binder composition further comprises an additive selected from a group of mineral oils, silicone and/or silane. Item 21. A method of producing a bonded mineral fibre product which comprises the step of contacting the mineral fibres with an aqueous binder composition according to any of the claims 1 to 20. Item 22. The method of producing a bonded mineral fibre product according to item 21 wherein the method comprises the steps of: - making a melt of raw materials, - fiberizing the melt by means of a fibre forming apparatus to form mineral fibres, wherein the mineral fibres formed are preferably directed into a spinning chamber, - providing the mineral fibres in the form of a collected web, - applying the aqueous binder composition on the mineral fibres before, during or after the provision of the collected web to form a mixture of mineral fibres and binder composition, wherein the aqueous binder composition is preferably applied by spraying before the provision of the collected web, preferably in the spinning chamber - curing the binder composition mixed with the mineral fibres. Item 23. The method of producing a mineral fibre product according to items 21 or 22, wherein the curing is carried out at temperatures from 180-360 °C, preferably 200-275 °C, more preferably 220-250 °C. Item 24. A mineral fibre product comprising mineral fibres bound by a binder resulting from the curing of an aqueous binder composition according to any of the items 1 to 20. Item 25. A mineral fibre product obtainable by a method according to any one of items 21 to 23. Item 26. Use of an aqueous binder composition according to any of the items 1 to 20 for the production of a mineral fibre product. Item 27. Use of an aqueous binder composition according to any of the items 1- 20 for lowering the formaldehyde and/or ammonia and/or phenol emissions during production of a mineral fibre product. Item 28. A method of reducing the formaldehyde emission and/or the ammonia and/or phenol emission during application of a phenol-urea- formaldehyde binder (PUF binder) on mineral fibres in a spinning chamber, said method comprising the step of - adding a carbohydrate binder to the PUF binder to obtain an aqueous binder composition, wherein the carbohydrate binder comprises a component (a) in the form of one or more carbohydrates, and a component (b) in the form of: (bi) one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof, or (bii) one or more compounds selected from hypophosphorous derivatives of hypophosphorous acid or any salt thereof, or (biii) a mixture of (bi) and (bii), wherein component (a) is present in the aqueous binder composition in an amount of at least 20 % by weight based on the binder component solids, and - applying the resulting aqueous binder composition instead of the PUF binder on the mineral fibres, preferably in the spinning chamber, wherein the method is preferably a method according to any one of items 21-23. Item 29. Use of an aqueous binder composition according to any of the items 1- 20 for lowering the formaldehyde emissions of a cured mineral fibre product. Item 30. A method of reducing the formaldehyde emission in a mineral fibre product, prepared with a phenol-urea-formaldehyde binder (PUF binder), said method comprising the steps of - adding a carbohydrate binder to the PUF binder to obtain an aqueous binder composition, wherein the carbohydrate binder comprises a component (a) in the form of one or more carbohydrates, and a component (b) in the form of: (bi) one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof, and (bii) one or more compounds selected from hypophosphorous acid, derivatives of hypophosphorous acid or any salt thereof, wherein component (a) is present in the aqueous binder composition in an amount of at least 20 % by weight based on the binder component solids, - applying the resulting aqueous binder composition onto the mineral fibres, preferably in the spinning chamber, and - curing the aqueous binder composition.

Claims

Claims 1. An aqueous binder composition for mineral fibres comprising a mixture of I) a phenol-urea-formaldehyde binder (PUF binder), and II) a carbohydrate binder comprising: a component (a) in the form of one or more carbohydrates; a component (b) in the form of: (bi) one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof, wherein component (a) is present in an amount of at least 20 % by weight based on the binder component solids.

2. The aqueous binder composition according to claim 1, wherein component (b) of the carbohydrate binder further comprises a component (bii) in the form of one or more compounds selected from hypophosphorous acid, derivatives of hypophosphorous acid or any salt thereof.

3. The aqueous binder composition according to claim 1, wherein the PUF binder and the carbohydrate binder are mixed in a ratio such that the proportion by weight B, based on the combined weight of A+B, is in the range of 20 to 95% by weight, wherein B is the weight of the binder solids of the carbohydrate binder and A is the weight of the binder solids of the PUF binder.

4. The aqueous binder composition according to claim 2, wherein the proportion by weight B, based on the combined weight of A+B, is in the range of 25 to 90%.

5. The aqueous binder composition according to claim 2 or 3, wherein the proportion by weight A, based on the combined weight of A+B, is in the range of 5 to 50% by weight, preferably 10 to 45% by weight, more preferably 20 to 40 % by weight, or wherein the proportion by weight B, based on the combined weight of A+B, is in the range of 50 to 95% by weight, preferably 55 to 90% by weight, more preferably 60 to 80% by weight.

6. The aqueous binder composition according to any of the preceding claims, wherein with respect to the starting materials phenol, formaldehyde and urea for preparing the PUF binder the molar ratio of phenol to formaldehyde is from 1:2.5 to 1:6; preferably from 1:3 to 1:5, and/or the amount of urea is from 20 to 60% by weight, preferably 30 to 50% by weight, based on total weight of phenol, formaldehyde and urea.

7. The aqueous binder composition according to any of the preceding claims, wherein the PUF binder is modified with ammonia wherein the amount of ammonia is preferably 0.1 to 6% by weight, more preferably 0.5 to 4% by weight, most preferably 1 to 3% by weight of the PUF binder component solids.

8. An aqueous binder composition according to any of the preceding claims, wherein component (a) is one or more carbohydrates having a DE value of 60 to 100, in particular 85 to 100, more particular 95 to 100.

9. An aqueous binder composition according to any preceding claims, wherein the component (a) is a glucose syrup having a DE of 60 to 100, in particular of 85 to 100, more particular 95 to 99.

10. An aqueous binder composition according to any of the preceding claims, wherein the component (a) is dextrose having a DE of 85 to 100.

11. An aqueous binder composition according to any of the preceding claims, wherein the component (a) is a hexose, such as fructose, and/or a pentose such as xylose.

12. An aqueous binder composition according to any of the preceding claims wherein component (a) is present in an amount of at least 20% to 90% by weight of binder component solids, more preferably 40 to 90 % by weight of binder component solids, most preferably 60 to 80% by weight of binder component solids.

13. An aqueous binder composition according to any of the preceding claims, wherein component (bi) is selected from the group consisting of ammonium sulfamate, calcium sulfamate, sodium sulfamate, potassium sulfamate, magnesium sulfamate, cobalt sulfamate, nickel sulfamate, N-cyclohexyl sulfamic acid and any salt thereof, such as sodium N-cyclohexyl sulfamate, or combinations thereof.

14. An aqueous binder composition according to any of the preceding claims, wherein the component (bii) is selected from the group consisting ammonium hypophosphite or sodium hypophosphite, or combinations thereof.

15. An aqueous binder composition according to any of the preceding claims, wherein the component (bi) is within the range of 0.5 to 20 wt%, in particular 1 to 15 wt%, more particular 1 to 5 wt% based on binder component solids of the carbohydrate binder (component II).

16. An aqueous binder composition according to any of the preceding claims wherein the component (b) is a mixture of (bi) and (bii).

17. An aqueous binder composition according to any of the preceding claims, wherein the mass ratio of component (bi) to component (bii) is preferably ≥1:1, more preferably between 3:1 to 5:1, most preferably 4:1.

18. An aqueous binder composition according to any one of the preceding claims wherein the proportion of component (b) is within the range of 1 to 15 wt%, in particular 1-12 wt%, more particular 2-10 wt% based on binder component solids of the carbohydrate binder (component (II)).

19. An aqueous binder composition according to any of the preceding claims, wherein the carbohydrate binder (component (II)) further comprises a component (c) in the form of ammonia, wherein the amount of ammonia is preferably 0.01 to 2 % by weight, more preferably 0.01 to 1 % by weight based on binder component solids.

20. An aqueous binder composition according to any of the preceding claims, wherein the carbohydrate binder (component (II)) further comprises a component (d) in the form of urea, wherein the amount of urea is preferably 0.5 to 6 % by weight, more preferably 1 to 5 % by weight, more preferably 2 to 4 % by weight based on binder component solids.

21. An aqueous binder composition according to any one of the preceding claims, wherein the binder composition further comprises an additive selected from a group of mineral oils, silicone and/or silane.

22. A method of producing a bonded mineral fibre product which comprises the step of contacting the mineral fibres with an aqueous binder composition according to any of the claims 1 to 21.

23. The method of producing a bonded mineral fibre product according to claim 22 wherein the method comprises the steps of: - making a melt of raw materials, - fiberizing the melt by means of a fibre forming apparatus to form mineral fibres, wherein the mineral fibres formed are preferably directed into a spinning chamber, - providing the mineral fibres in the form of a collected web, - applying the aqueous binder composition on the mineral fibres before, during or after the provision of the collected web to form a mixture of mineral fibres and binder composition, wherein the aqueous binder composition is preferably applied by spraying before the provision of the collected web, preferably in the spinning chamber - curing the binder composition mixed with the mineral fibres.

24. The method of producing a mineral fibre product according to claims 21 or 22, wherein the curing is carried out at temperatures from 180-360 °C, preferably 200-275 °C, more preferably 220-250 °C.

25. A mineral fibre product comprising mineral fibres bound by a binder resulting from the curing of an aqueous binder composition according to any of the claims 1 to 21.

26. A mineral fibre product obtainable by a method according to any one of claims 22 to 24.

27. Use of an aqueous binder composition according to any of the claims 1 to 21 for the production of a mineral fibre product.

28. Use of an aqueous binder composition according to any of the claims 1-21 for lowering the formaldehyde and/or ammonia and/or phenol emissions during production of a mineral fibre product.

29. A method of reducing the formaldehyde emission and/or the ammonia and/or phenol emission during application of a phenol-urea-formaldehyde binder (PUF binder) on mineral fibres in a spinning chamber, said method comprising the step of - adding a carbohydrate binder to the PUF binder to obtain an aqueous binder composition, wherein the carbohydrate binder comprises a component (a) in the form of one or more carbohydrates, and a component (b) in the form of: (bi) one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof, and (bii) one or more compounds selected from hypophosphorous acid, derivatives of hypophosphorous acid or any salt thereof, wherein component (a) is present in the aqueous binder composition in an amount of at least 20 % by weight based on the binder component solids, and - applying the resulting aqueous binder composition onto the mineral fibres in the spinning chamber.