Method for recycling mineral fibres of a material

Abstract

The present invention relates to a method comprising a step of contacting a material with at least one polyol, for a time and at a temperature sufficient to decompose a binder. The invention also relates to the use of a polyol to decompose the binder contained in a material that is in the form of a web, blanket or felt and contains mineral fibres and a binder comprising at least one thermoset resin.

Description

[0001] Description

[0002] Title: Process for recycling mineral fibers from a material

[0003] TECHNICAL FIELD

[0004] The present invention relates to the field of materials in the form of a veil, mattress or felt of mineral fibers bonded by a binder comprising at least one thermoset resin. The invention relates more particularly to a method comprising a step consisting of bringing said material into contact with at least one polyol, for a time and at a temperature sufficient to decompose said binder. It also relates to the use of a polyol for decomposing the binder contained in a material in the form of a veil, mattress or containing mineral fibers and a binder comprising at least one thermoset resin.

[0005] BACKGROUND OF THE INVENTION

[0006] The use of mineral fiber-based materials, particularly glass wool and fiberglass veils, has become widespread in the construction industry, particularly to meet regulatory requirements aimed at reducing the energy consumption of buildings and their environmental impact. Mineral wool-based materials are used as thermal or acoustic insulation, while mineral fiber veils can be used, among other things, as wall coverings, surfacing materials, or as a support layer for thermal or acoustic insulation products. Alternatively, mineral fiber veils can be used to manufacture shingles or waterproofing membranes for terraces or bituminous roofs.

[0007] Mineral wool blankets used as insulation have a certain lifespan and it may be necessary to change the substrate on which they are applied, particularly in the context of the renovation or transformation of a building or to replace them with more efficient insulating materials; this may also be the case for production waste (such as cutting waste).

[0008] Mineral fiber veils, for their part, generate waste, particularly at the end of production (cutting waste), during a manufacturing cycle or during transitions in their production process (non-compliant veils, typically the first and last veils in the cycle). Currently, these materials are landfilled or destroyed by combustion. It is also possible to remelt the glass. In the latter case, the resulting glass must then undergo a fiberizing step if it is to be reused. Furthermore, all these materials contain, in addition to mineral fibers, a binder intended to ensure the cohesion of the fibers between them and to give the material the desired mechanical properties. In the case of remelting the glass, it is therefore necessary to first remove the binder by combustion or pyrolysis.In the case of urea-formaldehyde or phenol-urea-formaldehyde binders, the combustion and pyrolysis processes generate pollutants such as nitrogen gases and / or sulfur oxides (SOx) that must be reprocessed. Their burial also poses a risk of soil pollution.

[0009] These processes therefore have a significant environmental and economic impact, particularly given their energy footprint. It would therefore be desirable to have a more environmentally friendly process for recycling these sails, i.e. for recovering the glass fibers they contain.

[0010] In this context, the inventors have developed a simple process for breaking down the binder by glycolysis, while preserving the structure of the fibers. The process according to the invention thus makes it possible to recycle these materials under economically acceptable conditions that are more environmentally favorable than current solutions.

[0011] It has already been suggested to use glycols in the recycling of polyurethane resins. Such a process comprises a step of contacting a polyether triol with a polyurethane resin, in the presence of an organic acid and a radical initiator, and then with diethylene glycol at 205-220°C (US2019 / 0359788). Alternatively, it has been proposed to use an oligomer of ethylene glycol or propylene glycol, such as diethylene glycol, in the presence of a catalyst which can be diethanolamine (KM Zia et al., Reactive & Functional Polymers 67 (2007) 675-692) or sodium hydroxide (D. Simon et al., Waste Management 76 (2018) 147-171).

[0012] To the Applicant's knowledge, it has never yet been suggested to apply a glycolysis process to the recycling of mineral fiber-based materials. Furthermore, with regard to urea-formaldehyde-based resins, which are commonly used in fiberglass webs, it has at most been proposed to subject wood panels comprising them to a solvolysis process in the presence of hydrochloric acid (M. Liu et al., Journal of Hazardous Materials, 355 (2018) 96-103; A. Nuryawan et al., Heliyon 6 (2020) e03936, 1-6). However, this acid hydrolysis requires corrosive reagents that generate polluting effluents.

[0013] SUMMARY OF THE INVENTION

[0014] The present invention thus relates to a method for recycling a material in the form of a veil, mattress or felt of mineral fibers glued with a binder comprising at least one thermoset resin, said method comprising a step consisting of bringing said material into contact with at least one polyol, for a time and at a temperature sufficient to decompose said binder and where the binder comprises:

[0015] - a urea-formaldehyde resin or a melamine-formaldehyde resin, or

[0016] - the product of the reaction between compounds comprising:

[0017] • at least one saccharide chosen from monosaccharides, disaccharides, oligosaccharides, polysaccharides and their mixtures, and / or

[0018] • at least one polycarboxylic acid chosen from monomeric and polymeric carboxylic acids, their anhydrides and their mixtures.

[0019] It also relates to the use of a polyol for decomposing the binder contained in a material in the form of a veil, a mattress or containing mineral fibers and a binder comprising at least one thermoset resin. Where said binder is as defined above.

[0020] DETAILED DESCRIPTION

[0021] The present invention relates to a method for recycling a material originating, for example, from the collection of renovation or demolition site waste or factory waste or waste from a production line. By "recycling" is meant a method for treating the material to recover the mineral fibers it contains and possibly reuse them in the manufacture of a new material.

[0022] This material can be a veil of mineral fibers or a mattress or mineral wool felt.

[0023] In the context of this description, "mineral wool" means a mass of tangled discontinuous mineral fibers of varying length. The air pockets present between the fibers give the material formed from mineral wool thermal and / or acoustic insulation properties. These are therefore insulating materials. "Insulating material" means a material that limits the heat exchange between two surfaces that it separates and that is characterized by a thermal conductivity λ of less than 0.05 W / mK and generally greater than 0.02 W / mK. It is in the form of a mattress or felt whose nominal thickness is generally between 10 and 400 mm, for example between 15 and 350 mm, preferably between 20 and 300 mm. Its density is preferably between 2 and 220 kg / m 3 , in particular from 5 to 180 kg / m 3 , preferably between 10 and 100 kg / m 3 and more preferably between 10 and 60 kg / m 3Mineral fibers typically make up 80 to 99% of the weight of mineral wool material.

[0024] By "nominal thickness" is meant the thickness of the mattresses or felts as they are marketed, in compressed form or not.

[0025] The manufacture of mineral wool insulation products generally includes a step of manufacturing the wool itself, which can be implemented by different processes, for example according to the known technique of fiberizing by internal or external centrifugation. Centrifugation consists of introducing the molten mineral material (glass or rock) into a centrifugal device comprising a multitude of small orifices, the material being projected towards the peripheral wall of the device under the action of centrifugal force and escaping in the form of filaments. At the outlet of the centrifugal device, the filaments are stretched and carried towards a receiving member by a gas current having a high temperature and speed, to form a sheet of fibers (or mineral wool).

[0026] To ensure the assembly of the fibers together and allow the sheet to have cohesion, a sizing composition in the form of an aqueous solution containing a thermosetting resin is sprayed onto the fibers, on the path from the outlet of the centrifugal device to the receiving member. The sheet of fibers coated with the sizing is then subjected to a heat treatment, at a temperature generally above 100°C, in order to carry out the polycondensation of the resin and thus obtain a thermal and / or acoustic insulation product having specific properties, in particular dimensional stability, tensile strength, thickness recovery after compression and a uniform color.

[0027] By "mineral fiber veil" is meant, in the context of this description, a non-woven material based on mineral fibers, the thickness of which is generally less than or equal to 2 mm, preferably less than or equal to 1 mm and generally between 250 and 500 pm or between 700 and 1000 pm. Its surface mass is generally between 20 and 500 g / m 2 , preferably 30 to 250 g / m 2 , for example from 35 to 110 g / m 2 or 150 to 250 g / m 2 .

[0028] The mineral fibers may be filaments or yarns composed of a multitude of filaments and assemblies of such yarns. Thus, according to a first embodiment, the mineral fiber veil is composed of mineral filaments of length up to 150 mm, preferably from 1 to 100 mm and advantageously from 2 to 50 mm, and having a diameter which may vary to a large extent, for example from 5 to 30 μm.

[0029] According to a second embodiment, the mineral fiber veil is composed of mineral yarns. The mineral yarns may be yarns composed of a multitude of mineral filaments (or base yarns) or assemblies of these base yarns into rovings. The aforementioned yarns may be untwisted yarns or twisted yarns (or textile yarns), preferably untwisted. The mineral yarns, in particular glass yarns, are generally cut to a length of up to 100 mm, preferably between 6 and 40 mm, in particular between 10 and 35 mm. The diameter of the glass filaments constituting the yarns may vary widely, for example between 5 and 30 μm. Similarly, wide variations may occur in the linear density of the yarn, which may range from 34 to 1500 tex. The glass constituting the filaments may be of any type, for example C, E, R, ECR or AR (alkali resistant). C and E glass are preferred.

[0030] In one embodiment, the nonwoven web may further be reinforced by a network of mineral yarns, in particular glass yarns with or without twist, preferably arranged parallel to each other. Each yarn is composed of a multitude of very fine filaments. These mineral yarns are generally deposited on the web conveyor device in the direction of advancement of the web and distributed over all or part of the width of the mat. They are preferably deposited between two layers of mineral fibers.

[0031] In one embodiment, the non-woven web therefore comprises mineral threads, in particular glass threads, arranged parallel to each other, and preferably in the machine direction, between two layers of randomly arranged mineral fibers.

[0032] Mineral fiber veils can be manufactured using known processes operating by dry or wet method.

[0033] In the dry process, molten material from a furnace is fed to a set of spinnerets from which filaments flow by gravity and are drawn by a gas flow. The filaments are collected on a conveyor where they intertwine.

[0034] On the upper face of the material thus formed, a sizing composition containing at least one thermosetting resin is applied using a suitable device, most often operating by curtain deposition, and the excess sizing composition is removed by suction at the opposite face. The material then enters a hot air oven whose temperature is adapted to remove the water and crosslink the resin in a fairly short time, then the veil of mineral fibers formed is collected and rolled up.

[0035] In the wet process, the veil is obtained from an aqueous dispersion of chopped mineral fibers which is deposited by means of a forming head on a conveyor equipped with perforations and the water is extracted through the conveyor by means of a suction box. The chopped fibers remaining on the conveyor form a veil which is treated under the same conditions as those described for the dry process.

[0036] The mineral fibers making up mineral wool or mineral fiber fleece can be made of glass or rock fibers or a mixture of glass and rock fibers.

[0037] Glass fibers can be of any type.

[0038] These may thus be biosoluble fibers as described in application WO2022 / 229571A1, having the following composition:

[0039] SiOz: 50 to 75%, preferably 60 to 70%

[0040] NaIO: 10 to 25%, preferably 10 to 20%

[0041] CaO: 5 to 15%, preferably 5 to 10%

[0042] MgO: 1 to 10%, preferably 2 to 5%

[0043] CaO and MgO together preferably representing 5 to 20%

[0044] B2O3: 0 to 10%, preferably 2 to 8%

[0045] AI2O3: from 0 to 8%, preferably from 1 to 6%

[0046] K2O: 0 to 5%, preferably 0.5 to 2%

[0047] Na2O and K2O together preferably representing 12 to 20%

[0048] Iron oxide: from 0 to 3%, preferably less than 2%, more preferably less than 1%, other oxide(s): from 0 to 5% by cumulative weight, preferably less than 3% by cumulative weight, the remainder being made up of unavoidable impurities.

[0049] Alternatively, the glass fibers may be high alumina fibers, typically having the following composition:

[0050] SiO2: 30 to 50%, preferably 35 to 45%,

[0051] Na2O: from 0 to 20%, preferably from 0.4 to 7%,

[0052] CaO: 6 to 35%, preferably 12 to 25%,

[0053] MgO: 1 to 15%, preferably 5 to 13%,

[0054] CaO+MgO: from 11 to 40% cumulative, AI2O3: from 10 to 27%

[0055] K2O: from 0 to 15%, preferably from 0 to 1%,

[0056] Iron oxide: from 0.5 to 15%, preferably from 3 to 12%, other oxide(s): from 0 to 5% cumulative, preferably less than 3%, the remainder being made up of unavoidable impurities,

[0057] Apart from the mineral fibres, the material used according to the invention contains a binder itself comprising at least one thermoset resin, i.e. a crosslinked, insoluble and infusible polymer system. The binder can be obtained by curing a sizing composition, which consists of an aqueous solution containing a mixture of organic and possibly inorganic compounds (sometimes referred to as "resin") capable of reacting with each other at high temperature.

[0058] However, it is preferred that the mineral fiber-based material be free of phenolic resin (novolac or resol resin). Alternatively or additionally, it is preferred that this material be free of polyurethane resin.

[0059] In one embodiment of the invention, the binder comprises a urea-formaldehyde resin or a melamine-formaldehyde resin, preferably a urea-formaldehyde resin.

[0060] This embodiment is particularly well suited to mineral fiber sails.

[0061] In another embodiment of the invention, the thermoset resin is the product of the reaction between compounds comprising:

[0062] - at least one saccharide chosen from monosaccharides, disaccharides, oligosaccharides, polysaccharides and their mixtures, hereinafter referred to as “the saccharide”, and / or

[0063] - at least one polycarboxylic acid chosen from monomeric and polymeric carboxylic acids, their anhydrides and their mixtures, hereinafter referred to as “polycarboxylic acid”.

[0064] Thus, in a first embodiment, the binder may comprise the product of the reaction of a polycarboxylic acid with a co-reactant chosen from: at least one saccharide chosen from monosaccharides, disaccharides, oligosaccharides, polysaccharides and mixtures thereof; at least one alkanolamine; at least one polyol other than a saccharide; at least one polyamine; and mixtures thereof.

[0065] The polycarboxylic acids used in this embodiment are preferably monomeric polycarboxylic acids, generally having a molar mass less than or equal to 1000. In other words, this term does not encompass polymers obtained by polymerization of monomeric carboxylic acids.

[0066] Polycarboxylic acids chosen from the group consisting of dicarboxylic acids, tricarboxylic acids and tetracarboxylic acids will preferably be used.

[0067] The dicarboxylic acids are for example chosen from the group formed by oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, malic acid, tartaric acid, tartronic acid, aspartic acid, glutamic acid, fumaric acid, itaconic acid, maleic acid, traumatic acid, camphoric acid, phthalic acid, tetrahydrophthalic acid, chlorendic acid, isophthalic acid, terephthalic acid, mesaconic acid and citraconic acid. Tricarboxylic acids are, for example, selected from the group consisting of citric acid, tricarballylic acid, 1,2,4-butanetricarboxylic acid, aconitic acid, hemimellitic acid, trimellitic acid and trimesic acid. Tetracarboxylic acids are, for example, 1,2,3,4-butanetetracarboxylic acid and pyromellitic acid.

[0068] The particularly preferred monomeric polycarboxylic acid is citric acid.

[0069] Alternatively, the polycarboxylic acids used in this embodiment of the present invention may be polymeric polycarboxylic acids, generally having a molar mass greater than 1000, such as homopolymers of acrylic, methacrylic, crotonic, isocrotonic, maleic, cinnamic, itaconic, 2-methylmaleic or 2-methylitaconic acid. Examples of anhydrides of these acids are succinic, glutaric, trimellitic, maleic, itaconic, phthalic, tetrahydrophthalic, acrylic and methacrylic anhydrides. Mention may also be made of copolymers of these acids or anhydrides with each other and / or with a vinyl comonomer. In an embodiment particularly suitable for mineral wool-based insulating materials, the co-reactant used with the aforementioned acids is a saccharide chosen from monosaccharides, disaccharides, oligosaccharides, polysaccharides and mixtures thereof.

[0070] The monosaccharide may be selected from monosaccharides containing 3 to 8 carbon atoms, preferably 5 to 7 carbon atoms. Preferred monosaccharides are hexoses such as glucose, mannose, galactose, psicose and fructose, and pentoses such as xylose, arabinose, ribose, ribulose, lyxose and xylulose.

[0071] The disaccharides may be chosen from sucrose, lactose and maltose, preferably sucrose.

[0072] For the purposes of this description, the term "oligosaccharides" means compounds containing from 3 to 8 monosaccharide units in the form of aldoses and / or ketoses, such as raffinose, manninotriose, stachyose and verbascose.

[0073] Examples of polysaccharides are arabinan, galactan, glucan, manan, and xylan.

[0074] Oligo- and polysaccharides (optionally mixed with mono- and / or disaccharides) may alternatively be extracted from plants. In particular, starch hydrolysates (including dextrins and glucose syrups) and cellulose and / or hemicellulose hydrolysates may be mentioned, in particular hydrolysates of bagasse or sugar cane molasses or beet molasses. The starch itself may be extracted from plants chosen from vegetables, legumes, fruits and seeds, in particular rice, peas, potatoes, cassava, sweet potatoes, wheat, maize, rye, rice, barley, millet, oats, sorghum, chestnuts or hazelnuts.

[0075] The saccharides used in the manufacture of the binder can be chosen from reducing sugars, non-reducing sugars and hydrogenated sugars.

[0076] The term "hydrogenated sugar" means all the products resulting from the reduction of a saccharide chosen from monosaccharides, disaccharides, oligosaccharides and polysaccharides and mixtures of these products. Hydrogenated sugars are also called sugar alcohols, alditols or polyols. They can be obtained by catalytic hydrogenation of saccharides. The hydrogenation can be carried out by known methods operating under conditions of high hydrogen pressure and temperature, in the presence of a catalyst chosen from the elements of groups IB, MB, IVB, VI, VII and VIII of the periodic table of elements, preferably from the group comprising nickel, platinum, palladium, cobalt, molybdenum and mixtures thereof. The preferred catalyst is Raney nickel.

[0077] The hydrogenated sugar(s) are advantageously chosen from the group consisting of erythritol, arabitol, xylitol, sorbitol, mannitol, iditol, maltitol, isomaltitol, lactitol, cellobitol, palatinitol, maltotritol, and the hydrogenation products of starch hydrolysates or hydrolysates of lignocellulosic materials, in particular hemicellulose, in particular xylans and xyloglucans.

[0078] Particular preference will be given to using a hydrogenated sugar chosen from the group formed by maltitol, xylitol, sorbitol and the hydrogenation products of starch hydrolysates or lignocellulosic materials.

[0079] The reducing sugars are preferably selected from monosaccharides such as glucose, galactose, mannose and fructose, disaccharides such as lactose, maltose, isomaltose, cellobiose and mixtures thereof, as well as the starch or lignocellulosic material hydrolysates described above. Glucose, xylose and mixtures thereof, in particular glucose, will preferably be used.

[0080] The non-reducing sugars are preferably disaccharides such as trehalose, isotrehaloses, sucrose, isosucroses and mixtures thereof. Sucrose is particularly preferred.

[0081] In a preferred embodiment of the invention, the thermoset resin is the product of the reaction between said at least one saccharide and said at least one polycarboxylic acid, preferably between at least one hydrogenated sugar and said at least one polycarboxylic acid. In this case, the polycarboxylic acid is a monomeric acid, preferably citric acid, or a polymeric acid, preferably polyacrylic acid. Thermosetting resins for mineral wool based on saccharides and polycarboxylic acids are described in detail in international applications WO2009 / 080938, WO2010 / 029266, WO2013 / 014399, WO2013 / 021112 and WO2015 / 132518 in the name of the Applicant. It is preferred to use bio-sourced reagents comprising at least 70% by weight, preferably at least 80%, and ideally at least 90% by weight of hydrogenated sugars and citric acid.Instead of or in addition to a saccharide, at least one alkanolamine may be used as a co-reactant with the aforementioned polycarboxylic acids or their anhydrides. Binders based on these acids and alkanolamines include those comprising the addition / elimination products of aliphatic and / or aromatic polycarboxylic acid anhydrides with alkanolamines such as diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, methyldiethanolamine, ethyldiethanolamine, n-butyldiethanolamine, methyldiisopropanolamine, ethylisopropanolamine, ethyldiisopropanolamine, 3-amino-1,2-propanediol, 2-amino-1,3-propanediol and tris(hydroxymethyl)aminomethane, preferably diethanolamine. These binders are described in particular in applications W02004 / 007615 and W02006 / 0061249.

[0082] Examples of polyols (other than hydrogenated sugars) used as co-reactants with the acids described above are alkylene glycols, in particular ethylene glycol, glycerol, pentaerythritol, trimethylolpropane, resorcinol, catechol, pyrogallol, 1,4-cyclohexanediol, and addition polymers comprising at least two hydroxyl groups, such as poly(vinyl alcohol). As binders based on carboxylic polymers and polyols, mention may be made of those described in application US2004 / 002567.

[0083] Other co-reactants include polyamines such as diethylenetriamine, triethylenetetramine or tetraethylenepentamine. Binders based on polycarboxylic acids and polyamines are described in particular in application US 2007 / 0173588.

[0084] In another embodiment of the invention, the thermoset resin is the product of the reaction of at least one saccharide as described above with a co-reactant other than a polycarboxylic acid or in addition to said polycarboxylic acid.

[0085] In the case in particular where the saccharide comprises a reducing sugar, for example glucose or xylose, preferably glucose, at least one co-reactant is preferably used, chosen from nitrogenous or amino compounds, in particular ammonia; a primary or secondary amine, linear, branched or cyclic (optionally heterocyclic); a protein, a peptide or an amino acid; an amino-amide; or an ammonium salt of a monomeric or polymeric carboxylic acid, such as citric acid, of a mineral acid, such as sulfuric or phosphoric acid, or of an organophosphonic or organosulfonic acid; and mixtures thereof. Such binders based on Maillard reagents are known, for example, from applications WO2007 / 014236, WO2009 / 019232 and WO2012 / 037451.

[0086] The binder present in the mineral fiber-based material comprises from 15% to 100% by weight, preferably from 50 to 95% by weight, and more preferably from 75 to 90% by weight, of thermoset resin such as those described above.

[0087] The other constituents of the binder may be derived from the sizing composition or from the reaction between components of the sizing composition and at least one of the constituents of the resin described above and / or produced by heating components of the sizing composition. The sizing composition may comprise at least one component chosen from: a catalyst, which may in particular be chosen from Lewis bases and acids, such as clays, colloidal or non-colloidal silica, amines, quaternary amines, metal oxides (including ZnO and CaO), metal sulfates, metal chlorides, urea sulfates, urea chlorides and silicate-based catalysts, or a compound containing phosphorus, for example an alkali metal hypophosphite salt, an alkali metal phosphite, an alkali metal polyphosphate, an alkali metal hydrogen phosphate, a phosphoric acid or an alkylphosphonic acid,the alkali metal being advantageously sodium or potassium, or a compound containing fluorine and boron, for example tetrafluoroboric acid or a salt of this acid, in particular an alkali metal tetrafluoroborate such as sodium or potassium, an alkaline earth metal tetrafluoroborate such as calcium or magnesium, a zinc tetrafluoroborate and an ammonium tetrafluoroborate, preferably sodium hypophosphite, sodium phosphite and mixtures of these compounds; a silane, in particular an aminosilane; an oil; urea; glycerol; a silicone; an “extender” chosen for example from lignin derivatives such as ammonium lignosulfonate (ASL) or sodium lignosulfonate and animal or vegetable proteins; a pH adjuster; a flame retardant; a surfactant; a rheology modifier; an antifoaming agent; and mixtures thereof. The sizing composition also contains water.

[0088] In addition, the sizing composition used for the manufacture of the binder may contain at least one polysaccharide, as described in application WO2016 / 00106, such as an optionally modified starch or a dextrin (WO2022 / 106789) or one or more ethylene-vinyl acetate copolymers, as described in application WO2018 / 138429, or one or more latexes. In the case where it constitutes a web of mineral fibers, the material used according to the invention advantageously contains from 60 to 95% by weight of mineral fibers and preferably from 65 to 90% by weight of mineral fibers, for example from 75 to 85% by weight of mineral fibers, relative to the dry weight of the web. It advantageously contains from 5 to 40% by weight of binder, preferably from 10 to 35% by weight of binder, for example from 15 to 25% by weight of binder, relative to the dry weight of the web. In one embodiment of the invention, the weight ratio of fibers to binder is from 3:1 to 5:1.

[0089] In the case where this material is a felt or a mineral wool mattress, mineral fibers represent 80 to 99% of the weight of the material.

[0090] When the binder consists solely of combustible organic components, this binder content is identical to what is usually referred to in the technical field of glass textiles as loss on ignition (LOI). The binder may, however, contain a certain fraction of mineral components, for example mineral particulate fillers. This fraction generally does not exceed 20% by weight of the binder. When the binder contains such a mineral filler, its loss on ignition (LOI) will therefore be lower than the binder content of the non-woven web of mineral fibres.

[0091] In the method according to the present invention, a material comprising a binder as described above is reacted with at least one polyol, which may for example be chosen from: linear diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 2-methyl-1,2-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,10-decanediol, 1,12-dodecanediol; cyclic diols such as 1,4-cyclohexanedimethanol, 1,6-cyclohexanedimethanol, 1,4-cyclohexanediol; triols such as glycerol, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanetriol, erythritol, pentaerythritol;polyalkylene glycols, comprising homopolymers and copolymers resulting from the reaction of alkylene oxides, in particular ethylene oxide and / or propylene oxide, and water, sugar(s) and / or polyol(s) as defined above, said polyalkylene glycols preferably having a number-average molecular mass ranging from 50 to 10,000 g / mol, in particular from 60 to 5,000 g / mol and in particular from 100 to 600 g / mol, such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol; polyglycerols, preferably having a number average molecular weight ranging from 50 to 10,000 g / mol, such as glycerol ethoxylate and propoxylate, polyglycerol-3 (glycerol trimer) and decaglycerol; and mixtures thereof.;

[0092] According to the invention, it is preferred not to use glycerol. More particularly, the polyol is advantageously chosen from polyalkylene glycols, preferably having a number-average molecular mass ranging from 50 to 10,000 g / mol, in particular from 60 to 5,000 g / mol and in particular from 100 to 600 g / mol, such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, more preferably diethylene glycol.

[0093] The insulating material may be brought into contact with the polyol by any means enabling the entire material to be treated to be brought into contact with the polyol, and in particular by dipping, spraying or coating, preferably by immersing the material in a solution containing, or consisting of, the polyol. The polyol may optionally be mixed with an organic solvent and / or water, although it is preferred not to use organic solvents. Furthermore, in a preferred embodiment, this solution does not comprise an amine, an alkali hydroxide, an alkali acetate and / or an organometallic compound. The material is brought into contact with the polyol at a temperature and for a time sufficient to decompose the binder, which a person skilled in the art can easily adjust.It can thus be carried out at a temperature of 25 to 250 °C and is preferably carried out at a temperature of 100 to 230 °C, for example 140 to 160 °C or 200 to 220 °C, for a period of time ranging for example from 1 h to 24 h, preferably from 2 h to 15 h. The duration of the reaction will generally be longer the lower the temperature.

[0094] The method according to the invention may further comprise steps of recovering the material treated with the polyol, washing, preferably with water or with an aqueous solution, and drying, in order to obtain mineral fibers. These mineral fibers can then be reused in the manufacture of a new material, possibly after carding.

[0095] EXAMPLES

[0096] The following examples illustrate the invention without, however, limiting it.

[0097] Example 1: Decomposition of a urea-formaldehyde resin binder General protocol

[0098] A glass veil is cut into pieces of approximately 2x2 cm. The pieces are then immersed in a flask containing diethylene glycol, in a proportion of 2 to 5% w / v of veil in the solvent. The mixture is heated in an oil bath at 150 or 210°C for 4 hours, under atmospheric pressure. The fibers are then recovered by filtration under reduced pressure, then rinsed with water. If they are to be reused, the fibers are generally not dried. Alternatively, the fibers can be dried by rinsing with acetone and then drying at room temperature.

[0099] Measurement of the quantity of binder by “loss on ignition”

[0100] The recycled fibers as described above (0.5 to 1.0 g) are subjected to pyrolysis at 550 °C for 1 h in air. The quantity of residual binder after glycolysis is assimilated to the mass lost by pyrolysis. It is calculated as follows:

[0101] [Chem 1]

[0102] Final LAW (100

[0103] The initial LOI of the veil is determined in the same way.

[0104] Tests were carried out on a sample of a non-woven web having a thickness of 330 pm and a surface mass of 35 g / m 2 , comprising glass fibers and a urea-formaldehyde resin binder.

[0105] The results of these tests are presented in the Table below:

[0106] [Table 1]

[0107] These tests show that glycols allow effective solvolysis of urea-formaldehyde type binders.

[0108] Furthermore, the fibers could be easily disentangled. Their general appearance was evaluated after treatment using a scanning electron microscope: no fiber degradation or residual binder was observed. Using this technique, the diameter of the initial fibers was estimated at 13.6 ± 1.5 pm, while that of the fibers after solvolysis was estimated at 14.0 ± 1.2 pm. The solvolysis process using glycols therefore does not lead to glass dissolution.

[0109] The sails shown in the table below were made: [Table 2]

[0110] The so-called "recycled" fibers are produced by solvolysis in diethylene glycol at 150 °C as presented above. Cohesive webs have been obtained with up to 20% by mass of recycled fibers compared to the total mass of fibers in the web. Although a slight loss in tensile strength of the webs tends to be observed with increasing recycled fiber content in the web, this is due to a lower LOI (and therefore binder content) for these webs. Indeed, the tensile strength to LOI ratio of the webs is substantially constant regardless of the recycled fiber content used.

Claims

Claims 1. Method for recycling a material in the form of a veil, mattress or felt of mineral fibers glued with a binder comprising at least one thermoset resin, said method comprising a step consisting of bringing said material into contact with at least one polyol, for a time and at a temperature sufficient to decompose said binder and where the binder comprises: - a urea-formaldehyde resin or a melamine-formaldehyde resin, or - the product of the reaction between compounds comprising: • at least one saccharide chosen from monosaccharides, disaccharides, oligosaccharides, polysaccharides and their mixtures, and / or • at least one polycarboxylic acid chosen from monomeric and polymeric carboxylic acids, their anhydrides and their mixtures.

2. Method according to claim 1, characterized in that the binder comprises a urea-formaldehyde resin.

3. Method according to claim 1, characterized in that the binder is the product of the reaction of said at least one polycarboxylic acid with a co-reactant chosen from: at least one saccharide chosen from monosaccharides, disaccharides, oligosaccharides, polysaccharides and their mixtures; at least one alkanolamine; at least one polyol other than a saccharide; at least one polyamine; and their mixtures, preferably the binder is the product of the reaction between said at least one saccharide and said at least one polycarboxylic acid, more preferably between at least one hydrogenated sugar and said at least one polycarboxylic acid.

4. Method according to claim 3, characterized in that the polycarboxylic acid is a monomeric acid, preferably citric acid, or a polymeric acid, preferably polyacrylic acid.

5. Method according to claim 1, characterized in that the saccharide is a reducing sugar and the binder is the product of the reaction of said at least one saccharide with at least one co-reactant chosen from: nitrogenous or amino compounds, in particular ammonia; a primary or secondary amine, linear, branched or cyclic (optionally heterocyclic); a protein, a peptide or an amino acid; an amino-amide; or an ammonium salt of an acid monomeric or polymeric carboxylic acid, such as citric acid, of a mineral acid, such as sulfuric or phosphoric acid, or of an organophosphonic or organosulfonic acid; and mixtures thereof.

6. Method according to claim 5, characterized in that the reducing sugar is chosen from glucose, xylose and their mixtures, preferably glucose.

7. Process according to any one of claims 1 to 6, characterized in that the polyol is chosen from: linear diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 2-methyl-1,2-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,10-decanediol, 1,12-dodecanediol; cyclic diols such as 1,4-cyclohexanedimethanol, 1,6-cyclohexanedimethanol, 1,4-cyclohexanediol; triols such as glycerol, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanetriol, erythritol, pentaerythritol;polyalkylene glycols, comprising homopolymers and copolymers resulting from the reaction of alkylene oxides, in particular ethylene oxide and / or propylene oxide, and water, sugar(s) and / or polyol(s) as defined above, said polyalkylene glycols, preferably having a number-average molecular weight ranging from 50 to 10,000 g / mol, in particular from 60 to 5,000 g / mol and in particular from 100 to 600 g / mol, such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol; polyglycerols, preferably having a number-average molecular weight ranging from 50 to 10,000 g / mol, such as glycerol ethoxylate and propoxylate, polyglycerol-3 (glycerol trimer) and decaglycerol; and mixtures thereof.; 8. Method according to any one of claims 1 to 7, characterized in that the contacting of the material and the polyol is carried out by immersing the material in a solution containing, or consisting of, the polyol, preferably at a temperature of 25 to 250°C, more preferably of 100 to 230°C.

9. Method according to any one of claims 1 to 8, characterized in that the material is a veil of mineral fibers and the mineral fibers represent from 60 to 95% of the weight of the material.

10. Method according to any one of claims 1 to 8, characterized in that the material is a felt or a mineral wool mat and the mineral fibers represent from 80 to 99% of the weight of the material.

11. Method according to claim 10, characterized in that it further comprises steps of recovering the material treated with the polyol, washing, preferably with water or with an aqueous solution, and drying, in order to obtain mineral fibers.

12. Use of a polyol as defined in any one of claims 1 or 7 for decomposing the binder contained in a material in the form of a veil, a mattress or containing mineral fibers and a binder comprising at least one thermoset resin chosen from - a urea-formaldehyde resin or a melamine-formaldehyde resin, or - the product of the reaction between compounds comprising: • at least one saccharide chosen from monosaccharides, disaccharides, oligosaccharides, polysaccharides and their mixtures, and / or • at least one polycarboxylic acid chosen from monomeric and polymeric carboxylic acids, their anhydrides and their mixtures.

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