Method for reducing the formaldehyde emission of a mineral fiber product based on a phenol-urea-formaldehyde binder

Abstract

The invention relates to a method of reducing a formaldehyde emission of a mineral fiber product including a phenol-urea-formaldehyde binder, said method comprising the steps of I) providing an aqueous binder composition which is a mixture of i) a phenol -urea-formaldehyde binder (PUF binder) and ii) a carbohydrate binder comprising a component a) in form of one or more carbohydrates; II) applying the aqueous binder composition to mineral fibers and III) curing the binder composition mixed with the mineral fibers at a temperature in the range of 220 to 280 °C, preferably 240 to 280 °C, more preferably 245 to 265 °C and even more preferably 255 to 265 °C to form the mineral fiber product, wherein component a) is present in an amount of at least 20% by weight of the binder components solids of the carbohydrate binder, wherein the curing is carried out in a curing oven through which the binder composition mixed with the mineral fibers is conveyed in form of a collected web, wherein the production rate of cured mineral fiber product from the curing oven is 2.5 to 50 t / h.

Description

[0001] M / ROCK-202-PC

[0002] Method for reducing the formaldehyde emission of a mineral fiber product based on a phenol-urea-formaldehyde binder

[0003] Description

[0004] Field of the Invention

[0005] The present invention relates to a method of reducing a formaldehyde emission of a mineral fiber product including a phenol-urea-formaldehyde binder and a carbohydrate binder, a mineral fiber product obtainable by the method, and the use of a carbohydrate binder as a formaldehyde scavenger for reducing the formaldehyde emission of a mineral fiber product. The present invention relates further to an aqueous binder composition which is a mixture of a phenol-urea-formaldehyde binder and a carbohydrate binder.

[0006] Background of the Invention

[0007] Mineral wool products generally comprise man-made vitreous fibers (MMVF) such as, e.g., glass fiber, ceramic fibers, basalt fibers, 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 fiber mats are generally produced by converting a melt made of suitable raw materials to fibers in a conventional manner, for instance by internal centrifugation (spinning cup process) or by external centrifuging (cascade rotor process). The fibers 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 fiber 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 fibers together.

[0008] Phenolic binders, in particular phenol-formaldehyde resole resins are frequently used in the manufacture of mineral fiber insulation materials, such as insulative batts for walls, roof boards, ceiling tiles, insulative coverings for pipes, and the like.M / ROCK-202-PC

[0009] 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 fibers in a spinning chamber and curing. Moreover, a particular concern is formaldehyde released from the cured resin in the mineral fiber product since these products in use are usually located near living spaces of the consumer where no safety measurements can be made. 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 from the mineral fiber product into the environment.

[0010] 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 fiber 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.

[0011] For instance, US-A-4339361 discloses phenol-formaldehyde resole resins which are suitable for use in binder systems for bonding mineral fiber 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.

[0012] 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. Such ammonia emissions are likewise undesirable, particularly in enclosed spaces, because it is hazardous to human health, and to the environment.

[0013] Various techniques have been used for lowering both the formaldehyde and the ammonia emissions from formaldehyde-based resins. In particular, sugar has been used for this purpose.M / ROCK-202-PC

[0014] 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.

[0015] WO2012 / 076462 relates to a method of reducing the formaldehyde emission of a mineral fiber 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.

[0016] 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.

[0017] US-A-2010 / 0075146 relates to a sizing composition which comprises phenol-urea-formaldehyde resin and a catalyst made of a mixture of ammonium sulfamate and ammonium sulfate. The sizing may be extended with saccharide as inexpensive extender. The saccharide component may be sugar cane or beet molasses.

[0018] 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 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 view of formaldehyde emission from the mineral fiber products 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.

[0019] WO2019 / 185762 Al relates to a method of manufacturing a composite product such as mineral fibers, comprising the application of an aqueous binder composition consisting of reducing sugar reactants, nitrogen -containing reactants and a resin.

[0020] In view of the cited prior art, there is still a need to provide an aqueous binder composition based on phenol-formaldehyde type binder suitable for bonding mineral fibers to prepare mineral fiberM / ROCK-202-PC

[0021] products, generating only small amounts of harmful gases after curing. In particular, the formaldehyde emissions of the mineral fiber product shall be reduced and kept low. At the same time mineral fiber products resulting from applying the binder to mineral fibers and curing shall have very good long term mechanical properties and a satisfactory low water uptake (or water absorption) and a low solubility.

[0022] Summary of the Invention

[0023] Accordingly, it was an object of the present invention to provide a method of reducing a formaldehyde emission of a mineral fiber product including a phenol-urea-formaldehyde binder which overcomes or alleviates the drawbacks of the prior art discussed above. At the same time the binder in the cured state should show satisfactory properties with respect to mechanical strength, solubility and water absorption.

[0024] 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, wherein the formaldehyde emission of the bonded mineral fiber product after curing can be reduced significantly when cured at a relative high temperature. In addition, the mixed aqueous binder composition provides in any case a reduction of formaldehyde emission as compared to pure PUF binders which cannot be explained by a mere dilution effect, i.e. by carbohydrates merely acting as a diluent or extender.

[0025] In accordance with a first aspect of the present invention, there is provided a method of reducing a formaldehyde emission of a mineral fiber product including a phenol-urea-formaldehyde binder, said method comprising the steps of

[0026] I) providing an aqueous binder composition which is a mixture of

[0027] i) a phenol-urea-formaldehyde binder (PUF binder) and

[0028] ii) a carbohydrate binder comprising a component a) in form of one or more carbohydrates,

[0029] II) applying the aqueous binder composition to mineral fibers and

[0030] III) curing the binder composition mixed with the mineral fibers at a temperature in the range of 220 to 280 °C, preferably 240 to 280 °C, more preferably 245 to 265 °C and even more preferably 255 to 265 °C to form the mineral fiber product,M / ROCK-202-PC

[0031] wherein component a) is present in an amount of at least 20% by weight of the binder components solids of the carbohydrate binder,

[0032] wherein it is preferred that the curing is carried out in a curing oven through which the binder composition mixed with the mineral fibers is conveyed in form of a collected web, wherein the production rate of cured mineral fiber product from the curing oven is 2.5 to 50 t / h, preferably 5 to 35 t / h, more preferably 5 to 25 t / h.

[0033] Accordingly, in a preferred embodiment the invention is directed to a method of reducing a formaldehyde emission of a mineral fiber product including a phenol-urea-formaldehyde binder, said method comprising the steps of

[0034] I) providing an aqueous binder composition which is a mixture of

[0035] i) a phenol-urea-formaldehyde binder (PUF binder) and

[0036] ii) a carbohydrate binder comprising a component a) in form of one or more carbohydrates,

[0037] II) applying the aqueous binder composition to mineral fibers and

[0038] III) curing the binder composition mixed with the mineral fibers at a temperature in the range of 220 to 280 °C, preferably 240 to 280 °C, more preferably 245 to 265 °C and even more preferably 255 to 265 °C to form the mineral fiber product,

[0039] wherein component a) is present in an amount of at least 20% by weight of the binder components solids of the carbohydrate binder,

[0040] wherein the curing is carried out in a curing oven through which the binder composition mixed with the mineral fibers is conveyed in form of a collected web, wherein the production rate of cured mineral fiber product from the curing oven is 2.5 to 50 t / h, preferably 5 to 35 t / h, more preferably 5 to 25 t / h.

[0041] The present inventors have surprisingly found that the inventive method provides mineral fiber products having significantly reduced formaldehyde emissions. In addition, the mixed binder as described herein provides improved mechanical properties of the mineral fiber product as compared to both the pure PUF binder and the pure carbohydrate binder.M / ROCK-202-PC

[0042] The inventive mixed binders usually retain the mechanical strength compared to pure PUF or are at a comparable level. Especially the aged mechanical strength is generally significantly improved compared to carbohydrate binders.

[0043] 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.

[0044] The improvements described for the mixed 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 binders, in particular when cured at a temperature in the range of 220 to 280 °C, preferably 240 to 280 °C, more preferably 245 to 265 °C and even more preferably 255 to 265 °C, according to the present invention.

[0045] Further advantages and features of the present invention will emerge from the description of preferred embodiments.

[0046] Description of the preferred embodiments

[0047] The present invention is directed to a method of reducing a formaldehyde emission of a mineral fiber product including a phenol-urea-formaldehyde binder, said method comprising the steps of I) providing an aqueous binder composition which is a mixture of

[0048] i) a phenol-urea-formaldehyde binder (PUF binder) and

[0049] ii) a carbohydrate binder comprising a component a) in form of one or more carbohydrates,

[0050] II) applying the aqueous binder composition to mineral fibers and

[0051] III) curing the binder composition mixed with the mineral fibers at a temperature in the range of 220 to 280 °C, preferably 240 to 280 °C, more preferably 245 to 265 °C and even more preferably 255 to 265 °C to form the mineral fiber product,M / ROCK-202-PC

[0052] wherein component a) is present in an amount of at least 20% by weight of the binder components solids of the carbohydrate binder,

[0053] wherein it is preferred that the curing is carried out in a curing oven through which the binder composition mixed with the mineral fibers is conveyed in form of a collected web, wherein the production rate of cured mineral fiber product from the curing oven is 2.5 to 50 t / h, preferably 5 to 35 t / h, more preferably 5 to 25 t / h.

[0054] The carbohydrate binder comprising a component a) in form of one or more carbohydrates can be added to the phenol-urea-formaldehyde binder (PUF binder) during and / or after preparation of the PUF binder, preferably after preparation of the PUF binder. It goes without saying that the addition is effected before curing of the aqueous binder composition applied to the mineral fibers.

[0055] In a preferred embodiment, 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.

[0056] In a preferred embodiment the one or more carbohydrates of the carbohydrate binder comprises a component a) comprises glucose (also termed dextrose) and / or glucose syrup in an amount of 60 to 100% by weight, preferably 80 to 100% by weight, more preferably 100% by weight of the binder component solids of the carbohydrate binder; wherein the component a) preferably has a DE value of 60 to 100, in particular of 85 to less than 100, more particular 95 to 99.

[0057] In a particularly preferred embodiment, the carbohydrate binder comprises component a) in form of one or more carbohydrates and at least one of a component b) in form of one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof, and a component c) in the form of one or more compounds selected from hypophosphorous acid, derivatives of hypophosphorous acid or any salt thereof, wherein it is particular preferred that the carbohydrate binder comprises component a) and component b) or comprises component a) and component c) or comprises component a), component b) and component c).

[0058] In a further preferred embodiment, the aqueous binder composition of the present invention is a mixed binder composition obtainable by mixing, preferably in-line mixing of

[0059] a stand-alone phenol-urea-formaldehyde binder (PUF),M / ROCK-202-PC

[0060] a carbohydrate binder comprising a component a) in the form of one or more carbohydrates,

[0061] component b) in the form of one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof,

[0062] optionally component c) in the form of one or more compounds selected from hypophosphorous acid, derivatives of hypophosphorous acid or any salt thereof, optionally ammonia

[0063] optionally urea

[0064] optionally silane

[0065] water.

[0066] In a further preferred embodiment, the aqueous binder composition of the present invention is a mixed binder composition obtainable by mixing, preferably in-line mixing of

[0067] a phenol-urea-formaldehyde resin,

[0068] ammonia

[0069] ammonium sulfate

[0070] component a) in the form of one or more carbohydrates,

[0071] component b) in the form of one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof,

[0072] optionally component c) in the form of one or more compounds selected from hypophosphorous acid, derivatives of hypophosphorous acid or any salt thereof optionally urea

[0073] optionally silane

[0074] water.

[0075] 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.

[0076] The aqueous binder composition used in the present invention as well as the PUF binder are particularly suitable as a binder for mineral fibers in order to produce mineral fiber products. Preferably, also the carbohydrate binder is particularly suitable as a binder for mineral fibers in order to produce mineral fiber products.

[0077] 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 areM / ROCK-202-PC

[0078] aqueous binders. Water can be added to the mixture, if necessary, for instance, in order to adjust the desired properties such as viscosity.

[0079] Aqueous binder composition

[0080] Component (i) - PUF binder

[0081] 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 fibers in the production of mineral fiber products.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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. The PUF binder is usually an aqueous PUF binder.

[0086] 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.M / ROCK-202-PC

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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 l°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.

[0091] 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.

[0092] The degree of conversion of phenol is preferably > 95%, more preferably > 97%.

[0093] The urea may be added to the resin, in particular the resol resin, during its preparation or in a post-reaction step.

[0094] 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.

[0095] 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 ammoniaM / ROCK-202-PC

[0096] 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.

[0097] 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.

[0098] 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.

[0099] In a further preferred embodiment, the PUF binder further comprises ammonium sulfate, wherein the amount of ammonium sulfate is preferably 1.5 to 4.4% by weight, more preferably 1.8 to 2.6% by weight, based on binder component solids of the PUF binder.

[0100] 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.

[0101] 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.

[0102] Component fii-) - Carbohydrate binder

[0103] 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

[0104] The carbohydrate binder is usually an aqueous binder. The binder can contain one or more carbohydrates. The carbohydrate binder is usually a formaldehyde-free binder, in particular no formaldehyde or reaction products thereof are included in the binder.

[0105] Component a-) of the carbohydrate binderM / ROCK-202-PC

[0106] Component a) is in the form of one or more carbohydrates.

[0107] 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.

[0108] In a preferred embodiment, the one or more carbohydrates has a DE value of 60 to 100, in particular 85 to 100, more particular 95 to 100, wherein the one or more carbohydrates are preferably selected from glucose and / or glucose syrup having a DE value of 60 to 100, in particular of 85 to less than 100, more particular 95 to 99.

[0109] In a preferred embodiment, the one or more carbohydrates of component a) are selected from sucrose, reducing sugars, in particular dextrose (glucose), 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.

[0110] In a preferred embodiment, the one or more carbohydrates have a DE value of 60 to 100, in particular 85 to 100, more particular 95 to 100.

[0111] In a preferred embodiment, the one or more carbohydrates is glucose and / or a glucose syrup, preferably having a DE value of 85 to 100 or less than 100, respectively.

[0112] In a further preferred embodiment, the one or more carbohydrates of component a) comprise or consist of glucose syrup, one or more hexoses, such as dextrose or fructose, one or more pentoses, such as xylose, or a mixture thereof.

[0113] In a further preferred embodiment, the carbohydrate is selected from hexoses, in particular a Hose, altrose, glucose, mannose, gulose, idose, galactose, talose, psicose, fructose, sorbose and / orM / ROCK-202-PC

[0114] tagatose; and / or pentoses, in particular arabinose, lyxose, ribose, xylose, ribulose and / or xylulose; and / or tetroses, in particular erythrose, threose, and / or erythrulose.

[0115] In a further preferred embodiment, the carbohydrate is selected from a hexose such as fructose, and / or a pentose such as xylose.

[0116] In a further preferred embodiment of the inventive method, the component a) is present in an amount of 20 to 100 % by weight, preferably 30 to 95% by weight, more preferably 40 to 90% by weight, more preferably 60 to 80% by weight, of the binder components solids of the carbohydrate binder.

[0117] In a preferred embodiment, the one or more carbohydrates (component a) of the carbohydrate binder comprises glucose and / or glucose syrup in an amount of 60 to 100% by weight, preferably 80 to 100% by weight, more preferably 100% by weight, based on the binder component solids of the carbohydrate binder; wherein component a) preferably has a DE value of 60 to 100, in particular of 85 to less than 100, more particular 95 to 99.

[0118] In this embodiment glucose and / or glucose syrup may be added to the binder composition during and / or after preparation of the PUF binder or binder composition, respectively.

[0119] 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.

[0120] Optional component bl of carbohydrate binder

[0121] In a preferred embodiment, the carbohydrate binder further comprises a component b) in 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:

[0122]

[0123] M / ROCK-202-PC

[0124] 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 b) 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, or combinations thereof.

[0125] Derivatives of sulfamic acid are e.g. O-substituted and / or N-substituted sulfamic acid compounds. In these derivatives the hydrogen positioned on the nitrogen and / or oxygen of the sulfamic acid is replaced with other groups, in particular organic groups. Either one or two or all three hydrogen atoms on the sulfamic acid molecule may be replaced with different or the same groups. Such organic groups may be selected from alkyl, preferably Ci to Cs alkyl, more preferably Ci to C4 alkyl; cycloalkyl, preferably C3 to C12 cycloalkyl, more preferably Cs to Cs cycloalkyl in particular cyclohexyl; aryl or alkaryl, such as phenyl, or heteroaryl. These organic groups may be substituted with one or more functional groups such as halogen, e.g. chlorine or bromine, hydroxyl, and alkyloxy.

[0126] In a preferred embodiment, the proportion of component b), if present, is within the range of 0.5 to 20% by weight, in particular 1 to 15% by weight, more particular 1 to 10% by weight such as 2 to 10% by weight, most particular 1 to 5% by weight, based on binder component solids of the carbohydrate binder.

[0127] In a preferred embodiment, component b) is sulfamic acid.

[0128] In a particular preferred embodiment, component b) is ammonium sulfamate.

[0129] In another preferred embodiment, the component b) is in form of N-cyclohexyl sulfamic acid and any salt thereof. The proportion of component b) in form of N-cyclohexyl sulfamic acid and any salt thereof is within the range of 0.5 to 20% by weight, in particular 1 to 15% by weight, more particular 1 to 10% such as 2 to 10 %, most particular 1 to 5 % by weight, based on the mass of binder component solids of the carbohydrate binder.

[0130] An advantage of the binder component b) 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.M / ROCK-202-PC

[0131] Optional component cl of the carbohydrate binder

[0132] In an embodiment of the invention, the carbohydrate binder further comprises a component c) in the form of one or more compounds selected from hypophosphorous acid, derivatives of hypophosphorous acid or any salt thereof. An example of a derivative of the hypophosphorous acid is an ester of the hypophosphorous acid.

[0133] Hypophosphorous acid, H3PO2 (or H2PO(OH)), is a mineral acid having the formula

[0134]

[0135] In a preferred embodiment, component c) is hypophosphorous acid.

[0136] In a further preferred embodiment, component c) is ammonium hypophosphite and / or sodium hypophosphite.

[0137] In a preferred embodiment, the carbohydrate binder comprises component b) or component c) and preferably both component b) and component c), i.e. a combination of sulfamic acid, derivatives of sulfamic acid or any salts thereof and hypophosphorous acid, derivatives of hypophosphorous acid or any salts thereof.

[0138] In a preferred embodiment, the proportion (binder component solids) of component c) of the carbohydrate binder is within the range 0.25 to 10% by weight, in particular 0.5 to 7.5% by weight, more particular 0.5 to 5% by weight based on binder component solids of the carbohydrate binder.

[0139] It has surprisingly been shown that by adding component c) such as hypophosphorous acid, the mechanical properties of the aqueous carbohydrate composition can be strongly improved.

[0140] Component c) can be used as the single component of the carbohydrate binder part of the inventive aqueous binder composition. However, a disadvantage of using only component c) in the carbohydrate binder part of the aqueous binder composition as described herein is the comparatively high price.M / ROCK-202-PC

[0141] The present inventors have found that by including a combination of component b) and component c) to the carbohydrate binder, both the unaged and aged mechanical strength of the aqueous binder composition described herein can be strongly improved.

[0142] In a further preferred embodiment, the ratio of component b) to component c) is >1:1, more preferably between 3:1 and 5:1, most preferably about 4:1 (3.5-4.5:1) in the carbohydrate binder or aqueous binder composition, respectively.

[0143] In particular, the present inventors have found that the addition of component c), i.e. hypophosphorous acid, derivatives of hypophosphorous acid or any salt thereof in a ratio of about 4:1 (3.5-4.5:1) of component b) to component c) nearly doubles the aged mechanical strength compared to only including component b), i.e. sulfamic acid, derivatives of sulfamic acid or any salts thereof in the aqueous binder composition according to the invention.

[0144] In another preferred embodiment the total amount of component b) and component c) is preferably within the range of 1 to 15% by weight, in particular 1 to 12% by weight, more particular 2 to 10% by weight, based on binder component solids of the carbohydrate binder.

[0145] 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 b) and component c) in the aqueous binder as compared to only adding component b).

[0146] Optional further components of the carbohydrate binder

[0147] In a preferred embodiment, the carbohydrate binder composition further comprises a component d) in the form of ammonia and / or an ammonium salt, preferably ammonia. The amount of ammonia and / or ammonium salt, preferably ammonia, is preferably in the range of 0.01 to 2 % by weight, more preferably 0.01 to 1 % by weight, based on the binder component solids of the carbohydrate binder.

[0148] In a further preferred embodiment, the aqueous carbohydrate binder composition further comprises a component e) in the form of urea. The amount of urea is preferably present in an amount of 0.5 to 10 % by weight, more preferably 1 to 7 % by weight, most preferably 2 to 6 % by weight, based on the weight of binder component solids.

[0149] The inclusion of urea in the binder described herein improves the fire resistance and anti-punking properties of the inventive binder.M / ROCK-202-PC

[0150] Final binder composition - mixing of component (i) and component (ii-)

[0151] The carbohydrate binder comprising a component a) in form of one or more carbohydrates can be added to the phenol-urea-formaldehyde binder (PUF binder) during and / or after preparation of the PUF binder, preferably after preparation of the PUF binder. It goes without saying that the addition is effected before curing of the aqueous binder composition applied to the mineral fibers.

[0152] In a preferred embodiment, 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.

[0153] In a particularly preferred embodiment of the present invention, the carbohydrate binder comprises 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 fibers. Both these components have a comparatively low price and are easy to handle.

[0154] 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.

[0155] 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 94% by weight, more preferably 25 to 95% by weight, more preferably 35 to 85% by weight, even more preferably 40 to 80% 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.

[0156] 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.M / ROCK-202-PC

[0157] 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.

[0158] 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 6 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.

[0159] 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 94% 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 6 to 50% by weight, more preferably 10 to 45% by weight, most preferably 20 to 40% by weight.

[0160] 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.

[0161] 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 fiber products produced with the inventive binder. The binders described herein can be of any pH. Preferably, the aqueous binder composition used in the invention has a pH of 6-11, preferably a pH of 7-11. In a particular preferred embodiment, the binders have a pH of 7-10.

[0162] Accordingly, the binder used in the present invention is not strongly acidic and thus not strongly corrosive.

[0163] In the context of the present invention, the "binder component solids" and the "binder solids" are defined as follows.

[0164] Binder component solids content - definitionM / ROCK-202-PC

[0165] 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:

[0166]

[0167] In case of calculating the binder component solids of dextrose only, the binder component A will be dextrose.

[0168] 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.

[0169] 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.

[0170] Binder solids - definition and procedure

[0171] The content by weight of binder after curing is termed "binder solids".

[0172] 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.

[0173] Reaction loss - definition

[0174] The reaction loss is defined as the difference between the binder component solids content and the binder solids.M / ROCK-202-PC

[0175] Optional additives of the aqueous binder composition

[0176] The aqueous binder composition used in the present invention may further comprise one of more additives.

[0177] 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.

[0178] 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).

[0179] 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.

[0180] 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.

[0181] 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.

[0182] As mentioned above, one or more mineral oil(s) may be added to the aqueous binder composition.

[0183] The additives can be added before or after mixing of the final binder.M / ROCK-202-PC

[0184] The method steps of the invention

[0185] The method of the present invention comprises as step I) providing an aqueous binder composition which is a mixture of

[0186] i) a phenol-urea-formaldehyde binder (PUF binder) and

[0187] ii) a carbohydrate binder comprising a component a) in form of one or more carbohydrates.

[0188] The details of the aqueous binder composition have been described above.

[0189] According to step II) of the inventive method, the aqueous binder composition is applied to mineral fibers.

[0190] The mineral fibers employed may be for instance any of man-made vitreous fibers (MMVF), glass fibers or glass wool, ceramic fibers, basalt fibers, slag fibers, stone fibers or stone wool and others. The mineral fibers are preferably of the types generally known as rock, stone or slag fibers, most preferably stone fibers. These fibers may be present as a wool product, e.g. like a stone wool product.

[0191] The man-made vitreous fibers can have any suitable oxide composition.

[0192] In the below, the iron oxide may be a mixture of FeO and Fe?O3 but is quoted herein as Fe20s.

[0193] Stone fibers commonly comprise the following oxides, in percent by weight:

[0194] SiCh: 30 to 51

[0195] AI2O3 : 12 to 25

[0196] CaO: 8 to 30

[0197] MgO: 2 to 25

[0198] Fe20s: 2 to 15

[0199] Na2O+K2O: not more than 10

[0200] CaO+MgO: 10 to 30

[0201] In preferred embodiments, the man-made vitreous fibers have the following levels of elements, calculated as oxides in wt%:

[0202] SiCh: at least 30, 32, 35 or 37; not more than 51, 48, 45 or 43

[0203] AI2O3: at least 12, 16 or 17; not more than 30, 27 or 25

[0204] CaO: at least 8 or 10; not more than 30, 25 or 20

[0205] MgO: at least 2 or 5; not more than 25, 20 or 15M / ROCK-202-PC

[0206] FeO (including Fe20s): at least 4 or 5; not more than 15, 12 or 10

[0207] FeO+MgO: at least 10, 12 or 15; not more than 30, 25 or 20

[0208] Na2O+K2O: zero or at least 1; not more than 10

[0209] CaO+MgO: at least 10 or 15; not more than 30 or 25

[0210] TiCh: zero or at least 1; not more than 6, 4 or 2

[0211] TiCh+FeO: at least 4 or 6; not more than 18 or 12

[0212] B2O3: zero or at least 1; not more than 5 or 3

[0213] P2O5: zero or at least 1; not more than 8 or 5

[0214] Others: zero or at least 1; not more than 8 or 5

[0215] Glass fibers commonly comprise the following oxides, in percent by weight:

[0216] SiO2 50 to 70

[0217] AI2O3 10 to 30

[0218] CaO not more than 27

[0219] MgO not more than 12

[0220] Glass fibers can also contain the following oxides, in percent by weight:

[0221] Na2O+K2O 8 to 18, in particular Na2O+K2O greater than CaO+MgO, and

[0222] B2O3 3 to 12.

[0223] Some glass fiber compositions can contain AI2O3 less than 2%.

[0224] Man-made vitreous fibers 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 vitreous fibers, for instance a shaft furnace such as a cupola furnace, a tank furnace, a submerged electrical furnace, or a cyclone furnace.

[0225] Any suitable method may be employed to form man-made vitreous fibers 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).

[0226] The melt is thus formed into a cloud of fibers entrained in air and the fibers are collected as a web on a conveyor and carried away from the fiberizing apparatus. The web of fibers is thenM / ROCK-202-PC

[0227] 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.

[0228] The application of the aqueous binder composition to the mineral fibers may be achieved through conventional means, for instance by spraying.

[0229] In a preferred embodiment, the aqueous binder composition is applied to the mineral fibers by spraying, wherein the aqueous binder composition is preferably sprayed on the mineral fibers in a spinning chamber, in which the mineral fibers are formed.

[0230] In a preferred embodiment, the aqueous binder composition is applied to the mineral fibers in the close vicinity of a fiber forming apparatus, such as a cascade spinning apparatus ora cup spinning apparatus, in either case immediately after the fiber formation. Thus, the aqueous binder composition is preferably applied to the mineral fibers formed in the spinning chamber, preferably by spraying. The fibers 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 fiber formation and before substantial curing has taken place.

[0231] In a preferred embodiment, the method of producing a bonded mineral fiber product comprises the steps of:

[0232] making a melt of raw materials,

[0233] fiberizing the melt by means of a fiber forming apparatus to form mineral fibers, wherein the mineral fibers formed are preferably directed into a spinning chamber,

[0234] providing the mineral fibers in the form of a collected web,

[0235] applying the aqueous binder composition to the mineral fibers before, during or after the provision of the collected web to form a mixture of mineral fibers 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,

[0236] curing the binder composition mixed with the mineral fibers.

[0237] There are various types of centrifugal spinners used as a fiber forming apparatus for fiberizing mineral melts.

[0238] 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 asM / ROCK-202-PC

[0239] 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 fibers are thrown off the or each subsequent rotor, and optionally also off the top rotor.

[0240] In one embodiment, a cascade spinner or other spinner is arranged to fiberize the melt, and the fibers are entrained in air as a cloud of the fibers.

[0241] Many fiber 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.

[0242] There is usually a stream of air associated with the one or each fiberizing rotor whereby the fibers are entrained in this air as they are formed off the surface of the rotor.

[0243] In one embodiment, the aqueous binder composition of the invention and / or additives are added to the cloud of fibers by known means. The amount of binder and / or additive may be the same for each spinner or it may be different.

[0244] In one embodiment, the aqueous binder composition of the invention and / or additives are added to the cloud of fibers by known means. The amount of binder and / or additive may be the same for each spinner or it may be different.

[0245] As used herein, the term "collected web" is intended to include any mineral fibers that have been collected together on a surface, i.e. they are no longer entrained in air, e.g. the fiberized mineral fibers, granulate, tufts or recycled web waste. The collected web could be a primary web that has been formed by collection of fibers on a conveyor belt and provided as a starting material without having been cross-lapped or otherwise consolidated.

[0246] Alternatively, the collected web could be a secondary web that has been formed by cross-lapping or otherwise consolidating a primary web.

[0247] Preferably, the collected web is a primary web.

[0248] The binder composition is applied to the fibers preferably when they are a cloud entrained in air. Alternatively, it can be applied after collection on the conveyor, but this is less preferred.M / ROCK-202-PC

[0249] The collected web is also often subjected to a consolidation operation before curing.

[0250] According to step III) of the inventive method, the binder composition mixed with the mineral fibers is cured to form the mineral fiber product.

[0251] The curing process may commence immediately after application of the binder composition to the mineral fibers. 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 mineral fibers to form a structurally coherent matrix of fibers.

[0252] 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 fibers and binder.

[0253] 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 fibers and binder. The blowing process may be accompanied by heating or cooling, or it may be at ambient temperature.

[0254] In a preferred embodiment, the curing takes place in a curing device such as in a conventional curing oven or a heat press.

[0255] The curing of a binder composition in contact with the mineral fibers in a heat press has the particular advantage that it enables the production of high-density products.

[0256] In a particularly preferred embodiment, the curing is carried out in a curing oven through which the binder composition mixed with the mineral fibers is conveyed, which is preferably in form of a collected web. The collected web has been discussed above so that reference is made thereto.

[0257] The curing of the aqueous binder composition which is applied to the mineral fibers is carried out at temperatures temperature in the range of 220 to 280 °C, preferably 240 to 280 °C, more preferably 242 to 275 °C, more preferably 245 to 265 °C and even more preferably 255 to 265°C.

[0258] The temperature at which the curing is effected in the curing oven preferably refers to the temperature of hot air entering the curing oven to heat the curing oven.M / ROCK-202-PC

[0259] In one embodiment, the curing takes place for a time of 30 seconds to 30 minutes, such as 1 to 15 minutes, such as 2 to 10 minutes.

[0260] In a typical embodiment, curing takes place at a temperature of 240 to 280 °C for a time of 30 seconds to 30 minutes.

[0261] In a preferred embodiment the collected web enters the curing oven through an opening inlet.

[0262] In a preferred embodiment, the curing oven includes a cabinet with an inlet opening for the collected web at one end of the cabinet and an outlet for the collected web at the opposed end of the cabinet and an air permeable conveyor on which the collected web is conveyed through the cabinet, wherein heated air is preferably introduced in the cabinet for curing.

[0263] In a preferred embodiment, the height of the inlet opening of the curing oven is in the range of 20 to 400 mm preferably in the range of 30 to 250 mm, more preferably 40 to 200 mm.

[0264] In a preferred embodiment the length of the curing oven in the conveying direction is preferably in the range of 5 to 70 m.

[0265] In a preferred embodiment the production rate of cured mineral fiber product from the curing oven is 2.5 to 50 t / h, preferably 5 to 35 t / h, more preferably 5 to 25 t / h.

[0266] An additional advantage of the binder compositions described herein is that they have a comparatively high curing speed at a low curing temperature.

[0267] 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 mineral fiber products.

[0268] In a preferred embodiment of the method the mineral fibers of the mineral fiber product have a median diameter of not more than 5 pm, such as 1 to 5 pm, preferably 3 to 5 pm or 1 to 2.5 pm, more preferably 1.5 to 2.3 pm.

[0269] In a preferred embodiment of the method the mineral fibers of the mineral fiber product have a median length of 100 to 3000 pm, preferably 1800 to 3000 pm or 100 to 300 pm, more preferably 150 to 250 pm.M / ROCK-202-PC

[0270] In a preferred embodiment of the method the mineral fibers have a median length of 100 to 300 pm, a median diameter of not more than 2.5 pm, preferably 1 to 2.5 pm, and wherein the ratio of the median fiber length to median fiber diameter is 25 to 500, preferably 100 to 300.

[0271] In an alternative preferred embodiment of the method the mineral fibers have a median length of 1800 to 3000 pm, a median diameter of 3 to 5 pm, and wherein the ratio of the median fiber length to median fiber diameter is 600 to 800.

[0272] Mineral fiber product

[0273] The present invention is also directed to a mineral fiber product comprising mineral fibers bound by a binder obtainable by the method according to the invention, wherein it is preferred that the mineral fibers have a median diameter of not more than 5 pm, such as 1 to 5 pm, preferably 3 to 5 pm or 1 to 2.5 pm, more preferably 1.5 to 2.3 pm.

[0274] In a preferred embodiment, the invention relates to a mineral fiber product comprising mineral fibers bound by a binder obtainable by a method according to the invention as described, wherein the mineral fibers have a median diameter of not more than 2.5 pm, preferably 1 to 2.5 pm, more preferably 1.5 to 2.3 pm.

[0275] The mineral fibers preferably have a median diameter of not more than 5 pm, such as 1 to 5 pm. In one embodiment, the median diameter is preferably 3 to 5 pm. In a preferred embodiment, the median diameter of the mineral fibers is less than 2.5 pm, preferably 1 to 2.5 pm, more preferably 1.5 to 2.3 pm.

[0276] In a preferred embodiment, the mineral fibers have a median length of 100 to 3000 pm, preferably 1800 to 3000 pm or 100 to 300 pm, more preferably 150 to 250 pm.

[0277] In a preferred embodiment, the mineral fibers of the mineral fiber product have a median length of 100 to 300 pm, preferably 150 to 250 pm, and a median diameter of 1 to 2.5 pm, preferably 1.5 to 2.3 pm, wherein the ratio of the median fiber length to median fiber diameter is preferably 25 to 500, preferably 100 to 300.

[0278] Without wishing to be limited by theory, it is thought that such combination of the median length of the mineral fibers, the median diameter of the mineral fibers result in improved properties of aM / ROCK-202-PC

[0279] mineral fiber substrate made from mineral fibers, wherein it is preferred that the ratio of the median fiber length to median diameter is as indicated above.

[0280] In another embodiment, the mineral fibers have a median length of 1800 to 3000 pm, a median diameter of 3 to 5 pm, wherein the ratio of the median fiber length to median fiber diameter is generally in the range of 600 to 800.

[0281] The median diameter of the mineral fibers can be obtained automatically using a scanning electron microscope (SEM) to measure the diameter of the fibers and counting the number of fibers in the sample.

[0282] The median length of the fibers can be obtained by the following method which is more precise than other measurement techniques and minimizes breaking of fibers. The process can be automated without introducing errors. Approximately 2 mg of mineral fibers is extracted from a sample which does not contain any binder. Typically, the binder is removed by heating to 590°C for at least 20 minutes. The mineral fibers are dispersed on to a glass platelet using an implosion initiated by vacuum. Pictures of the dispersed wool fibers are then acquired by optical microscopy in transmission mode. Prior to thresholding, the image is convolved with a neighborhood Gaussian filter to reduce the background noise and to bring uniformity along the fiber intensity values.

[0283] Thresholding is then performed: high gray-scale values correspond to fibers and low gray values are associated with the background or to residual noise. Isolated clustering of pixels of less than a few pixels or with an eccentricity of less than 0.5, that is, particles with roughly a circular shape, are removed as they correspond to either noise or shots. The medial axis of the fibers is then obtained through a skeleton algorithm. At this point, fibers are represented by only one pixel in width. To measure the length of each fiber, one should be able to differentiate one fiber from another including in the case where fibers cross. A score function is thus used to evaluate the probability of two segments of fibers belonging to the same fiber. The score function uses the angle difference and the distance between two segments. The score function is also used to reconstruct fibers that have been broken down to fiber segments during the thresholding step. Once each fiber is identified, the number of pixels representing it is counted and converted to the length in micrometers as the resolution of the images is known. If a fiber is crossing the border of the image, it is discarded.

[0284] The length of individual fibers is then established by measuring these parameters in the image. The median length of fibers in the sample is then calculated. At least 200 fibers should be measured, such as 250 fibers.M / ROCK-202-PC

[0285] All indications discussed above for the method also apply to the mineral fiber product of the present invention and vice versa.

[0286] In a preferred embodiment, the density of the mineral fiber 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.

[0287] In a preferred embodiment, the mineral fiber 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.

[0288] In an alternative embodiment, the mineral fiber product as described herein is a facade panel, in particular having a density of 1000-1200 kg / m3.

[0289] 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.

[0290] The mineral fiber 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.

[0291] In a particularly preferred embodiment, the mineral fiber product has a formaldehyde concentration after 28 days in a test chamber, according to EN16516:2017+Al:2020, of less than 60 pg / m3, preferably less than 40 pg / m3, more preferably less than 20 pg / m3, most preferably less than 10 pg / m3.

[0292] The formaldehyde concentration also called emission concentration Ca of formaldehyde is defined, measured and calculated according the standard EN16516:2017+Al:2020. Long term emissions shall be tested after 28 days after installation of the mineral fiber product in a test chamber.

[0293] The area specific emission rate SERA is defined, measured and calculated according to the standard EN16516:2017+Al:2020. Long term emissions shall be tested at 28 days after installation of the mineral fiber product in the test-chamber.M / ROCK-202-PC

[0294] 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 -mineral fiber product, when mixed aqueous binder and cured as described herein.

[0295] 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)).

[0296] However, surprisingly it has been shown that the actual formaldehyde emission reduction demonstrated for the cured mineral fiber product being bonded by the inventive aqueous binder mixture is significantly larger than expected. Thus, this aqueous mixed binder system in combination with the claimed curing temperature range 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.

[0297] In a further preferred embodiment, the mineral fiber product has a reduced concentration of formaldehyde after 28 days in a test chamber, according to EN16516:2017+Al:2020, by at least 25%, preferably by at least 35%, more preferably by at least 50%, with respect to a mineral fiber product based on pure phenol-urea-formaldehyde binder (PUF binder).

[0298] The reduced concentration of formaldehyde of the mineral fiber product can be calculated based on the formaldehyde concentration after 28 days in a test chamber, according to EN16516:2017+Al:2020. The reduction refers to the formaldehyde concentration after 28 days in a test chamber, according to EN16516:2017+Al:2020, of a mineral fiber product based on pure PUF binder, wherein the formaldehyde concentration of this binder is set to 100%. The curing temperature for the produced mineral fiber products based on pure PUF binder and the mixture of PUF binder and carbohydrate binder is the same, such as 260°C. For example, a mineral fiber product having a reduced concentration of formaldehyde by 25% therefore means that the concentration of formaldehyde is 75% as compared to that of the mineral fiber products based on pure PUF binder set to 100%.

[0299] 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 binderM / ROCK-202-PC

[0300] (component (i)) with carbohydrate binder (component (ii)) as described herein to the mineral wool products.

[0301] The reduction of formaldehyde emissions in a mineral fiber product also refers to a method of reducing a formaldehyde emission in a mineral fiber product, as described above.

[0302] Applications

[0303] The invention also relates to the use of a carbohydrate binder comprising a component a) in form of one or more carbohydrates as a formaldehyde scavenger for reducing the formaldehyde emission of a mineral fiber product based on a phenol-urea-formaldehyde binder (PUF binder) by adding the carbohydrate binder to the PUF binder to provide a mixture thereof as an aqueous binder composition, applying the aqueous binder composition to mineral fibers and curing the binder composition mixed with the mineral fibers at a temperature in the range of 220 to 280 °C, preferably 240 to 280 °C, more preferably 245 to 265 °C and even more preferably 255 to 265 °C to form the mineral fiber product, wherein component a) is present in an amount of at least 20% by weight of the binder components solids of the carbohydrate binder.

[0304] The use is preferably carried out in a method as described above.

[0305] Aqueous binder composition

[0306] The present invention is also directed to an aqueous binder composition which is a mixture of i) a phenol-urea-formaldehyde binder (PUF binder) and

[0307] ii) a carbohydrate binder comprising a component a) in form of one or more carbohydrates,

[0308] wherein component a) is present in an amount of at least 20% by weight of the binder components solids of the carbohydrate binder.

[0309] The aqueous binder composition has been described in detail above. Reference is made to all aspects described for the aqueous binder composition provided in step I) of the method according to the invention as disclosed above.

[0310] In a preferred embodiment, the PUF binder of the aqueous binder composition further comprises ammonium sulfate.M / ROCK-202-PC

[0311] In a preferred embodiment, the one or more carbohydrates of component a) comprise or consist of glucose syrup, one or more hexoses, such as dextrose or fructose, one or more pentoses, such as xylose, or a mixture thereof.

[0312] In a preferred embodiment, component a) is present in an amount of 20 to 100 % by weight, preferably 30 to 95% by weight, more preferably 40 to 90% by weight, more preferably 60 to 80% by weight, of the binder components solids of the carbohydrate binder in the aqueous binder composition.

[0313] In a preferred embodiment, the carbohydrate binder of the aqueous binder composition further comprises a component d) in the form of ammonia.

[0314] In a preferred embodiment, the aqueous binder composition further comprises a silane, preferably in an amount of 0.01 to 5%, based on the binder solids of the aqueous binder composition.

[0315] In a preferred embodiment, the carbohydrate binder of the aqueous binder composition further comprises a component c) in the form of one or more compounds selected from hypophosphorous acid, derivatives of hypophosphorous acid or any salt thereof, wherein the one or more compounds are preferably selected from ammonium hypophosphite and / or sodium hypophosphite.

[0316] In a preferred embodiment, the aqueous binder composition further comprises an additive selected from silicone and / or mineral oils.

[0317] The present invention is also directed to a mineral fiber product comprising mineral fibers bound by a cured aqueous binder composition according to the invention.

[0318] Examples

[0319] In the following examples, several binders which fall under the definition of the present invention were prepared and compared to binders according to the prior art.M / ROCK-202-PC

[0320] Experimental methods and definitions

[0321] Genera! experimental methods

[0322] 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.

[0323] 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.

[0324] 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.

[0325] FUNKTION heat resistant silicone forms for manufacture of bars (4x5 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.

[0326] 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.

[0327] 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.M / ROCK-202-PC

[0328] 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.

[0329] Binder component solids content - definition

[0330] 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:

[0331]

[0332] 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.

[0333] Binder solids - definition and procedure

[0334] The content of binder after curing is termed "binder solids".

[0335] 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 binder C) or 2 h at 225 °C (comparative binder B and comparative binder C). After cooling and storing at room temperatureM / ROCK-202-PC

[0336] for 10 minutes, the samples were weighed, and the binder solids were calculated as an average of the two results.

[0337] Reaction loss - definition

[0338] The reaction loss is defined as the difference between the binder component solids content and the binder solids.

[0339] Manufacture of composite bars (comparative binders A, B and C)

[0340] 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 binder C were cured for 2 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.

[0341] Manufacture of composite bars (binders D)

[0342] A 17.5% binder mixture comprising comparative binder A: comparative binder C in proportions of 85:15, 75:25, 60:40, 50:50, 40:60 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. The composite bars were then cured for 1 h at 200 °C. After cooling to room temperature, the composite bars were stored in a climate chamber at 22 °C / 50% rh.

[0343] Manufacture of composite bars (binder compositions according to the present invention)

[0344] A 17.5% binder mixture comprising comparative binder A: comparative binder B in proportions of 85:15, 75:25, 60:40, 50:50, 40:60 or 25:75 was obtained as described in the examples below. AM / ROCK-202-PC

[0345] 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. The composite bars were then 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.

[0346] Ageing treatment of composite bars

[0347] 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.

[0348] Measurement of mechanical strengths of composite bars

[0349] 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.

[0350] Measurement of loss of ignition (LOI) of composite bars

[0351] 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:

[0352] LOI (%)

[0353] Weight of bars before heat treatment (g) — Weight of bars after heat treatment g) Weight of bars before heat treatment g) x 100%M / ROCK-202-PC

[0354] Water absorption measurements

[0355] 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 0 = 9.5 cm; top 0 = 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:

[0356] Water abs. (%)

[0357] Weight of bars after water treatment (jg) — Weight of bars before water treatment (jg)

[0358] Weight of bars before water treatment g) x 100%

[0359] Curing characteristics - DMA (dynamic mechanical analysis) measurements

[0360] A 17.5% binder solids binder solution was obtained as described above. Cut and weighed glass Whatman™ glass microfiber filters (GF / B, 150 mm 0, cat. no. 1821 150) (2.5x1 cm) were submerged into the 17.5% binder solution for 10 seconds. The resulting binder-soaked filter was then dried in a "sandwich" consisting of (1) a 0.60 kg 8x8x1 cm metal plate, (2) four layers of standard filter papers, (3) the binder soaked glass microfiber filter, (4) four layers of standard filter papers, and (5) a 0.60 kg 8x8x1 cm metal plate for approximately 2x2 minutes by applying a weight of 3.21 kg on top of the "sandwich". In a typical experiment, the cut Whatman™ glass microfiber filter would weigh 0.035 g before application of the binder and 0.125 g after application and drying.

[0361] The DMA measurements were acquired on a Mettler Toledo DMA 1 calibrated against a certified thermometer at ambient temperature and the melting points of certified indium and tin. The apparatus was operated in single cantilever bending mode; titanium clamps; clamp distance 1.0 cm; temperature segment type; temperature range 40-280 °C; heating rate 3 °C / min; displacement 20 pm; frequency 1 Hz; single frequency oscillation mode. Curing onset and endset were evaluated using STARe software Version 12.00.M / ROCK-202-PC

[0362] Manufacture of stone wool products

[0363] Binder mixtures were obtained as described in the examples below (scaled up). Alternatively, the components could be mixed in an in-line fashion. The binder mixtures were diluted as appropriate with water and dosed to the cascade spinner. To decrease dust from the resulting stone wool product, impregnation oil (for example Process oil 815, Brenntag), was added in an amount that corresponds to approx. 0.1-0.2% of the stone wool. The stone wool product was then cured with air heated to the temperatures detailed in the tables by conveying it through a curing oven (line trials of Tables 1-7 to 1-10).

[0364] Measurement of accumulated formaldehyde emissions from cured binders

[0365] Accumulated formaldehyde emissions from cured composite bars and stone wool products 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.

[0366] Stone wool samples were obtained from factories in line trials. The samples were packed in airtight plastic bags immediately after production and were opened only just before setting up the experiments.

[0367] The maximum amount of wool product that could be placed into the steel sample holders was weighed off (approx. 3-4 g). The samples were then placed in 100 mL blue cap bottles containing 5 mL DNPH solution (obtained from 400 mg dinitrophenyl hydrazine, 50 mg cone, sulfuric acid, and acetonitrile to 1000 mL total volume) for stone wool samples. The bottles were closed tightly and sealed with parafilm.

[0368] 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.

[0369] After the designated amount of time, 1.00 mL of the DNPH solution was collected and passed through a 0.22 p 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.M / ROCK-202-PC

[0370] The data was converted into pg formaldehyde / g binder solids using the measured sample weights in combination with loss on ignition measurements obtained on unused stone wool samples.

[0371] The measurements are given in the tables both in absolute numbers and in relative index values compared to those of comparative binder A (index 100). Indexes equal to or above those of comparative binder A (>100), indexes in the range <100 to > 50, indexes in the range <50 to >25, indexes in the range <25 to >10 and indexes <10 can be considered as particular grades of quality.

[0372] Measurement of emission concentration Ca and specific emission rateSERA, formaldehyde

[0373] The emission concentration Ca of formaldehyde and specific emission rate SERA of formaldehyde from stone wool products were measured at Eurofins Product Testing Denmark A / S, Denmark. The following standards were complied with: EN 16516:2017+Al:2020 (test chamber, European reference room and expression of results), ISO 16000-3 (determination of aldehydes), ISO 16000-6 (determination of VOC, SVOC and WOC), ISO-16000-9 (determination of VOCs), ISO 16000-11 (sampling, storage of samples and preparation of test specimens), and ISO-16000-33 (determination of phthalates).

[0374] The measurements are given in the tables both in absolute numbers and in relative index values compared to those of comparative binder A (index 100). Indexes equal to or above those of comparative binder A (>100), indexes in the range <100 to > 50, indexes in the range <50 to >25, indexes in the range <25 to >10 and indexes <10 can be considered as particular grades of quality.

[0375] Comparative binder compositions from the prior art

[0376] Comparative binder A (phenoi-formaidehyde resin modified with urea, a PUF-resoi)

[0377] 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.

[0378] 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 toM / ROCK-202-PC

[0379] 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.

[0380] The acid tolerance (AT) is calculated by dividing the amount of acid used for the titration (mL) with the amount of sample (mL):

[0381] AT = (Used titration volume (mL)) / (Sample volume (mL))

[0382] 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).

[0383] Comparative binder B (carbohydrate binder)

[0384] N 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).

[0385] Comparative binder C (carbohydrate binder) [Dextrose alone]

[0386] mixture of 75% aq. glucose syrup (130.0 g) in water (133.5 g) was stirred at room temperature until 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 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 8.5-9.2).M / ROCK-202-PC

[0387] Binder compositions according to the present invention

[0388] Binders D (binder mixtures with comparative binder A : comparative binder C proportions of 85:15, 75:25, 60:40, 50:50, 40:60 or 25:75), examples DI -D6

[0389] 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 85:15, 75:25, 60:40, 50:50, 40:60 or 25:75) on a scale resulting in 80 g final binder mixture. After stirring for 1-2 minutes further, the resulting mixtures (pH 9.1-9.9) were used in the subsequent experiments.

[0390] Genera! binder example (binder mixtures with comparative binder A: comparative binder B proportions of 85:15, 75:25, 60:40, 50:50, 40:60 or 25:75), examples 1-6

[0391] 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 85:15, 75:25, 60:40, 50:50, 40:60 or 25:75) on a scale resulting in 80 g final binder mixture. After stirring for 1-2 minutes further, the resulting mixtures (pH 8.7-9.9) were used in the subsequent experiments.

[0392] 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 1-10.

[0393] TABLE 1-1: Binder compositions according to the prior art

[0394]

[0395] M / ROCK-202-PC

[0396]

[0397] [a]Of binder solids.M / ROCK-202-PC

[0398] TABLE 1-2: Binder compositions and properties of binder mixtures obtained using comparative

[0399]

[0400]

[0401] [a]Binder solids measured at 225 °C for 1 h.[b]of binder solids.M / ROCK-202-PC

[0402] TABLE 1-3: Binder compositions and properties of binder mixtures obtained using comparative

[0403]

[0404]

[0405] [a]Binder solids measured at 225 °C for 1 h.[b]of binder solids.M / ROCK-202-PC

[0406] TABLE 1-4: Properties from cured composite bars obtained using mixtures of comparative

[0407]

[0408]

[0409] [a]Binder solids measured at 225 °C for 1 h.M / ROCK-202-PC

[0410] TABLE 1-5: Properties from cured composite bars obtained using mixtures of comparative

[0411]

[0412]

[0413] [a]Binder solids measured at 225 °C for 1 h.M / ROCK-202-PC

[0414] TABLE 1-6: Properties from cured composite bars obtained using mixtures of comparative

[0415]

[0416]

[0417] [a]Binder solids measured at 225 °C for 1 h.M / ROCK-202-PC

[0418] TABLE 1-7: Formaldehyde emissions in cured stone wool products obtained using mixtures of comparative binders A and B

[0419]

[0420] M / ROCK-202-PC

[0421]

[0422] [a]Binder solids measured at 225 °C for 1 h.[b]1 bar, 121±2°C, 95±5 % RH.[c]70±2°C, 95±5 % RH.M / ROCK-202-PC

[0423] TABLE 1-8: Formaldehyde emissions in cured stone wool products obtained using mixtures of comparative binders A and B

[0424]

[0425] M / ROCK-202-PC

[0426]

[0427] M Binder solids measured at 225 °C for 1 h.

[0428]

[0429] 1 bar, 121±2°C, 95±5 % RH.[c]70±2°C, 95±5 % RH.M / ROCK-202-PC

[0430] TABLE 1-9: Formaldehyde emissions in cured stone wool products obtained using mixtures of comparative binders A, B and C

[0431]

[0432] M / ROCK-202-PC

[0433]

[0434] [a]Binder solids measured at 225 °C for 1 h.[b]1 bar, 121±2°C, 95±5 % RH.[c]70±2°C, 95±5 % RH.M / ROCK-202-PC

[0435] TABLE 1-10: Formaldehyde emissions in cured stone wool products obtained using mixtures of comparative binders A and B

[0436]

[0437] [a]Binder solids measured at 225 °C for 1 h.

[0438] The following observations can be made from the results present above.

[0439] The decrease in formaldehyde emissions from cured mineral fiber binders of the invention is greater than the substitution degree of the PUF binder with the carbohydrate binder.

Claims

M / ROCK-202-PCClaims1. A method of reducing a formaldehyde emission of a mineral fiber product including a phenol-urea-formaldehyde binder, said method comprising the steps ofI) providing an aqueous binder composition which is a mixture ofi) a phenol-urea-formaldehyde binder (PUF binder) andii) a carbohydrate binder comprising a component a) in form of one or more carbohydrates,II) applying the aqueous binder composition to mineral fibers andIII) curing the binder composition mixed with the mineral fibers at a temperature in the range of 220 to 280 °C, preferably 240 to 280 °C, more preferably 245 to 265 °C and even more preferably 255 to 265 °C to form the mineral fiber product, wherein component a) is present in an amount of at least 20% by weight of the binder components solids of the carbohydrate binder,wherein the curing is carried out in a curing oven through which the binder composition mixed with the mineral fibers is conveyed in form of a collected web, wherein the production rate of cured mineral fiber product from the curing oven is 2.5 to 50 t / h.

2. The method according to claim 1, wherein the mineral fiber product has a formaldehyde concentration after 28 days in a test chamber, according to EN16516:2017+Al:2020, of less than 60 pg / m3, preferably less than 40 pg / m3, more preferably less than 20 pg / m3, most preferably less than 10 pg / m3.

3. The method according to any of the preceding claims, wherein the mineral fiber product has a reduced concentration of formaldehyde after 28 days in a test chamber, according to EN16516:2017+Al:2020, by at least 25%, preferably by at least 35%, more preferably by at least 50%, with respect to a mineral fiber product based on pure phenol-urea-formaldehyde binder (PUF binder).

4. The method according to any of the preceding claims, wherein the carbohydrate binder further comprises a component b) in form of one or more compounds selected from sulfamic acid, derivatives of sulfamic acid or any salt thereof, wherein the one or more compounds are preferably selected from 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.M / ROCK-202-PC5. The method according to any of the preceding claims, wherein the carbohydrate preparation further comprises a component c) in the form of one or more compounds selected from hypophosphorous acid, derivatives of hypophosphorous acid or any salt thereof, wherein the one or more compounds are preferably selected from ammonium hypophosphite and / or sodium hypophosphite.

6. The method according to any of the preceding claims, wherein the PUF binder and the carbohydrate binder are mixed in a ratio such that the proportion by weight of B, based on the combined weight of A+B, is in the range of 20 to 94% by weight, preferably in the range of 25 to 90% by weight, more preferably 35 to 85% by weight, even more preferably 40 to 80% 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.

7. The method according to claim 6, wherein the proportion by weight of A, based on the combined weight of A+B, is in the range of 6 to 50% by weight, preferably 10 to 45% by weight, more preferably 20 to 40 % by weight, and / or wherein the proportion by weight of B, based on the combined weight of A+B, is in the range of 50 to 94% by weight, preferably 55 to 90% by weight, more preferably 60 to 80% by weight.

8. The method 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.

9. The method 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.

10. The method according to any of the preceding claims, wherein the PUF binder further comprises ammonium sulfate, wherein the amount of ammonium sulfate is preferably 1.5 to 4.4% by weight, more preferably 1.8 to 2.6% by weight, based on binder component solids of the PUF binder.

11. The method according to any of the preceding claims, wherein the component a) in form of one or more carbohydrates has a DE value of 60 to 100, in particular 85 to 100,M / ROCK-202-PCmore particular 95 to 100, wherein the one or more carbohydrates are preferably selected from glucose and / or glucose syrup having a DE value of 60 to 100, in particular of 85 to less than 100, more particular 95 to 99.

12. The method according to any of the preceding claims, wherein the one or more carbohydrates of component a) comprise or consist of glucose syrup, one or more hexoses, such as dextrose or fructose, one or more pentoses, such as xylose, or a mixture thereof.

13. The method according to any of the preceding claims, wherein the component a) is present in an amount of 20 to 100 % by weight, preferably 30 to 95% by weight, more preferably 40 to 90% by weight, more preferably 60 to 80% by weight, of the binder components solids of the carbohydrate binder.

14. The method according to any of the preceding claims 4 to 13, wherein the amount of component b) is within the range of 0.5 to 20% by weight, in particular 1 to 15% by weight, more particular 1 to 5% by weight, based on the binder component solids of the carbohydrate binder.

15. A method according to any of the preceding claims 5 to 14, wherein component b) and component c) are comprised in the carbohydrate binder, whereinthe mass ratio of component b) to component c) is preferably >1:1, more preferably between 3:1 to 5:1, most preferably 4:1, and / orwherein the total amount of component b) and component c) is preferably within the range of 1 to 15% by weight, in particular 1 to 12% by weight, more particular 2 to 10% by weight, based on binder component solids of the carbohydrate binder.

16. A method according to any of the preceding claims,wherein the carbohydrate binder further comprises a component d) 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 of the carbohydrate binder, and / orwherein the carbohydrate binder further comprises a component e) in the form of urea, wherein the amount of urea is preferably 0.5 to 10% by weight, more preferably 1 to 7% by weight, more preferably 2 to 6% by weight, based on binder component solids of the carbohydrate binder, and / orM / ROCK-202-PCwherein the aqueous binder composition further comprises one or more additives selected from a mineral oil, a silicone and a silane.

17. A method according to any of the preceding claims,wherein the mineral fibers have a median diameter of not more than 5 pm, preferably 1 to 5 pm, preferably 3 to 5 pm or 1 to 2.5 pm, more preferably 1.5 to 2.3 pm, and / or wherein the mineral fibers have a median length of 100 to 3000 pm, preferably 1800 to 3000 pm or 100 to 300 pm, more preferably 150 to 250 pm.

18. A method according to any of the preceding claims, wherein the production rate of cured mineral fiber product from the curing oven is 5 to 35 t / h, more preferably 5 to 25 t / h.

19. A method according to any of the preceding claims, wherein the height of the inlet opening of the curing oven is in the range of 20 to 400 mm preferably in the range of 30 to 250 mm, more preferably 40 to 200 mm.

20. A method according to any of any of the preceding claims, wherein the length of the curing oven in the conveying direction is preferably in the range of 5 to 70 m.

21. A method according to any of the preceding claims, wherein the curing oven includes a cabinet with an inlet opening for the collected web at one end of the cabinet and an outlet for the collected web at the opposed end of the cabinet and an air permeable conveyor on which the collected web is conveyed through the cabinet, wherein heated air is preferably introduced in the cabinet for curing.

22. The process according to any of the preceding claims,wherein the aqueous binder composition is applied to the mineral fibers by spraying, wherein the aqueous binder composition is preferably spayed on the mineral fibers in a spinning chamber, in which the mineral fibers are formed.

23. A mineral fiber product comprising mineral fibers bound by a binder obtainable by a method according to any of the previous claims, wherein the mineral fibers have a median diameter of not more than 2.5 pm, preferably 1 to 2.5 pm, more preferably 1.5 to 2.3 pm.M / ROCK-202-PC24. A mineral fiber product according to claim 23, wherein the mineral fibers have a median length of 100 to 3000 pm, preferably 1800 to 3000 pm or 100 to 300 pm, more preferably 150 to 250 pm.

25. A mineral fiber product according to claim 23 or 24,wherein the mineral fibers have a median length of 100 to 300 pm, a median diameter of not more than 2.5 pm, preferably 1 to 2.5 pm, and wherein the ratio of the median fiber length to median fiber diameter is 25 to 500.

26. A mineral fiber product according to any of claims 23 to 25,wherein the mineral fiber product has a formaldehyde concentration after 28 days in a test chamber, according to EN16516:2017+Al:2020, of less than 60 pg / m3, preferably less than 40 pg / m3, more preferably less than 20 pg / m3, most preferably less than 10 pg / m3, and / orwherein the mineral fiber product has a reduced concentration of formaldehyde after 28 days in a test chamber, according to EN16516:2017+Al:2020, by at least 25%, preferably by at least 35%, more preferably by at least 50%, with respect to a mineral fiber product based on pure phenol-urea-formaldehyde binder (PUF binder).

27. Use of a carbohydrate binder comprising a component a) in form of one or more carbohydrates as a formaldehyde scavenger for reducing the formaldehyde emission of a mineral fiber product based on a phenol-urea-formaldehyde binder (PUF binder) by adding the carbohydrate binder to the PUF binder to provide a mixture thereof as an aqueous binder composition, applying the aqueous binder composition to mineral fibers and curing the binder composition mixed with the mineral fibers at a temperature in the range of 220 to 280 °C, preferably 240 to 280 °C, more preferably 245 to 265 °C and even more preferably 255 to 265 °C to form the mineral fiber product, wherein component a) is present in an amount of at least 20% by weight of the binder components solids of the carbohydrate binder.

28. The use according to claim U in a method according to any one of claims 1 to 22.

29. An aqueous binder composition which is a mixture ofi) a phenol-urea-formaldehyde binder (PUF binder) andii) a carbohydrate binder comprising a component a) in form of one or more carbohydrates,M / ROCK-202-PCwherein component a) is present in an amount of at least 20% by weight of the binder components solids of the carbohydrate binder.

30. The aqueous binder composition of claim 29, wherein the PUF binder further comprises ammonium sulfate.

31. The aqueous binder composition according to claim 29 or claim 30, wherein the one or more carbohydrates of component a) comprise or consist of glucose syrup, one or more hexoses, such as dextrose or fructose, one or more pentoses, such as xylose, or a mixture thereof.

32. The aqueous binder composition according to any of claims 29 to 31, wherein the component a) is present in an amount of 20 to 100 % by weight, preferably 30 to 95% by weight, more preferably 40 to 90% by weight, more preferably 60 to 80% by weight, of the binder components solids of the carbohydrate binder.

33. The aqueous binder composition according to any of claims 29 to 32, wherein the carbohydrate binder further comprises a component d) in the form of ammonia.

34. The aqueous binder composition according to any of claims 29 to 33, wherein the aqueous binder composition further comprises a silane, preferably in an amount of 0.01 to 5%, based on the binder solids.

35. The aqueous binder composition according to any of claims 29 to 34, wherein the carbohydrate binder further comprises a component c) in the form of one or more compounds selected from hypophosphorous acid, derivatives of hypop hosphorous acid or any salt thereof, wherein the one or more compounds are preferably selected from ammonium hypophosphite and / or sodium hypophosphite.

36. The aqueous binder composition according to any of claims 29 to 35, wherein the aqueous binder composition further comprises an additive selected from silicone and / or mineral oils.

37. A mineral fiber product comprising mineral fibers bound by a cured aqueous binder composition, wherein the aqueous binder composition is according to any of claims 29

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