Process for recycling mineral fibers from an insulating material

Abstract

The present invention relates to a method for recycling an insulating material in the form of a mineral wool mat or felt containing mineral fibers which represent from 80 to 99% of the weight of the insulating material and a binder comprising at least one thermoset resin, said method comprising a step of bringing said insulating material into contact with at least one amine in liquid or gaseous form, for a time sufficient to decompose said binder. It also relates to the use of an amine for decomposing the binder contained in an insulating material in the form of a mat or felt containing mineral fibers which represent from 80 to 99% of the weight of the insulating material and a binder comprising at least one thermoset resin.

Description

Title of the invention: Process for recycling mineral fibers from an insulating material Technical field

[0001] The present invention relates to the field of thermal insulation products based on mineral wool, in particular glass or rock, and a binder comprising at least one thermoset resin.

[0002] The invention relates more particularly to a method for recycling an insulating material in the form of a mineral wool mattress or felt containing mineral fibers which represent from 80 to 99% of the weight of the insulating material and a binder comprising at least one thermoset resin, said method comprising a step of bringing said insulating material into contact with at least one amine in liquid or gaseous form, for a time sufficient to decompose said binder. BACKGROUND OF THE INVENTION

[0003] 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 drawn and driven towards a receiving member by a gas current having a high temperature and speed, to form a sheet of fibers (or mineral wool).

[0004] To ensure the assembly of the fibers together and to 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.

[0005] The most commonly used thermosetting resins are phenolic resins belonging to the resol family. In addition to their good ability to crosslink under the aforementioned thermal conditions, these resins are soluble in water, have a good affinity for mineral fibers, especially glass, and are relatively inexpensive.

[0006] Other sizing compositions are based on the use of a monomeric or polymeric polycarboxylic acid, and / or a saccharide, which may be a reducing or non-reducing sugar.

[0007] As indicated above, after application to the mineral fibers and hardening, the sizing composition forms a binder intended to ensure the cohesion of the fibers between them and to give the insulating product thus obtained the desired mechanical properties.

[0008] The insulating materials obtained have a certain lifespan and it may be necessary to remove them from 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. Currently, insulating materials are landfilled or incinerated, and more rarely recycled. Recycling generally involves melting the material in a furnace at very high temperatures in order to vaporize all the residues present, including the binder. The product obtained must then be subjected to a fiberizing step if the glass it contains is to be reused. This recycling process has a significant environmental impact, particularly given its energy balance.

[0009] There therefore remains a need for a more environmentally friendly process for recycling mineral wool-based insulating materials.

[0010] In this context, the inventors have developed a simple process for decomposing the binder by aminolysis at a moderate temperature, while preserving the structure of the fibers, so that it is no longer necessary to implement the melting and fiberizing steps used until now. The process according to the invention thus makes it possible to recycle insulating materials under economically acceptable and more environmentally favorable conditions, since the energy balance of the process is improved compared to current recycling processes.

[0011] It has already been suggested in application US 2019 / 0241713 to recycle a composite material based on a matrix formed from a phenolic resin incorporating glass fiber reinforcements. In this process, the composite material is subjected to an aminolysis step making it possible to recover, on the one hand, monomers or oligomers capable of reforming a resin and, on the other hand, the mineral fibers. However, it is not suggested that this process could be applied to products other than these composites, which are in the form of laminates formed from a stack of glass fiber fabrics impregnated with phenolic resin essentially intended for the manufacture of aeronautical or automotive parts, and in particular that this process could be used in the recycling of materials containing mainly mineral fibers in the form of wool, such as insulating materials. Furthermore, the inventors discovered that this aminolysis process has a universal character, in the sense that it can be applied to insulating materials containing all types of binders, which was not foreseeable in view of document US2019 / 0241713 which suggests that the described process is not even effective on all types of phenolic resin. Summary of the invention

[0012] The present invention thus relates to a method for recycling an insulating material in the form of a mineral wool mattress or felt containing mineral fibers which represent from 80 to 99% of the weight of the insulating material and a binder comprising at least one thermoset resin, said method comprising a step consisting of bringing said insulating material into contact with at least one amine in liquid or gaseous form, for a time sufficient to decompose said binder.

[0013] It also relates to the use of an amine to decompose the binder contained in an insulating material in the form of a mineral wool mattress or felt containing mineral fibers which represent from 80 to 99% of the weight of the insulating material and a binder comprising at least one thermoset resin. DETAILED DESCRIPTION

[0014] In the remainder of this description, the expression "between" must be understood as including the limits cited.

[0015] The present invention relates to a method for recycling an insulating material, originating for example from the collection of renovation or demolition site waste or factory waste.

[0016] By "insulating material" is meant a material limiting the heat exchange between two surfaces that it separates and which is characterized by a thermal conductivity X 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 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 5 and 220 kg / m3, more preferably between 10 and 180 kg / m3

[0017] The insulating material according to the present invention comprises glass wool, i.e. entangled mineral fibers, as well as a binder. More specifically, the mineral fibers represent from 80 to 99% of the weight of the insulating material. They may be glass or rock fibers or a mixture of glass and rock fibers.

[0018] Glass fibers can be of any type.

[0019] It may thus be biosoluble fibers such as described in application WO2022 / 229571A1, having the following composition:

[0020] SiO2: between 50 and 75%, preferably between 60 and 70%

[0021] Na2O: between 10 and 25%, preferably between 10 and 20%

[0022] CaO: between 5 and 15%, preferably between 5 and 10%

[0023] MgO: between 1 and 10%, preferably between 2 and 5%

[0024] CaO and MgO together preferably representing between 5 and 20%

[0025] B2O3: between 0 and 10%, preferably between 2 and 8%

[0026] A12O3: between 0 and 8%, preferably between 1 and 6%

[0027] K2O: between 0 and 5%, preferably between 0.5 and 2%

[0028] Na2O and K2O together preferably representing between 12 and 20%

[0029] Iron oxide: between 0 and 3%, preferably less than 2%, more preferably less than 1%,

[0030] other oxide(s): between 0 and 5% by weight in total, preferably less than 3% in total,

[0031] the remainder being made up of unavoidable impurities.

[0032] Alternatively, the glass fibers may be high alumina fibers, typically having the following composition:

[0033] SiO2: between 30 and 50%, preferably between 35 and 45%,

[0034] Na2O: between 0 and 20%, preferably between 0.4 and 7%,

[0035] CaO: between 6 and 35%, preferably between 12 and 25%,

[0036] MgO: between 1 and 15%, preferably between 5 and 13%,

[0037] CaO+MgO: between 11 and 40% cumulative,

[0038] A12O3: between 10 and 27%,

[0039] K2O: between 0 and 15%, preferably between 0 and 1%,

[0040] Iron oxide: between 0.5 and 15%, preferably between 3 and 12%,

[0041] other oxide(s): between 0 and 5% cumulative, preferably less than 3%,

[0042] the remainder being made up of unavoidable impurities,

[0043] Apart from the mineral fibres, the insulating material used according to the invention contains a binder 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 suitable for being sprayed onto the mineral fibres and containing a mixture of organic and possibly inorganic compounds (sometimes referred to as "resin") capable of reacting with each other at high temperature.

[0044] In one embodiment of the invention, the thermoset resin is a phenolic resin.

[0045] The phenolic resins usable according to the present invention include both novolac resins and resols, both of which are obtained by reaction of formaldehyde, and optionally another aldehyde, with phenol and optionally o-, p- and / or m-cresol.

[0046] Resols are prepared using excess formaldehyde under basic conditions, with the formaldehyde / phenol molar ratio typically ranging from 2 to 4, with each phenol molecule potentially reacting with three formaldehyde molecules. They contain numerous methylol functions carried by an aromatic ring, which constitute the sites of crosslinking by dehydration / formaldehyde release. These resins are essentially composed of phenol / formaldehyde condensates (PF), residual phenol and residual formaldehyde.

[0047] Novolac resins, on the other hand, are obtained by acid catalysis, using a substoichiometric amount of formaldehyde. Novolac resins require the use of a crosslinker, such as a polyamine, to form a thermoset resin.

[0048] According to the invention, it is preferred to use phenolic resins of the resol type, optionally modified with an amine, preferably a monoalkanolamine, and in particular monoethanolamine. This alkanolamine reacts according to the Mannich reaction with phenol / formaldehyde (PF) condensates, phenol and formaldehyde to form phenol / formaldehyde / amine (PFA) condensates. This amine phenolic resin consists essentially of phenol-formaldehyde condensates and phenol-formaldehyde-amine condensates. Resins of this type are notably described in application WO2008 / 043961.

[0049] In another embodiment of the invention, the thermoset resin is the product of the reaction between compounds comprising:

[0050] - at least one saccharide chosen from monosaccharides, disaccharides, oli saccharides, polysaccharides and mixtures thereof, hereinafter referred to as "the saccharide", and / or

[0051] - at least one polycarboxylic acid chosen from monocarboxylic acids meric and polymeric, their anhydrides and their mixtures, hereinafter referred to as "polycarboxylic acid".

[0052] Thus, in a first embodiment, the binder may comprise the product of the reaction of the 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.

[0053] 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 include polymers obtained by polymerization of monomeric carboxylic acids.

[0054] Polycarboxylic acids chosen from the group consisting of dicarboxylic acids, tricarboxylic acids and tetracarboxylic acids will preferably be used. boxylic.

[0055] 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.

[0056] The particularly preferred polycarboxylic acid is citric acid.

[0057] 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.

[0058] Preferably, the co-reactant used with the aforementioned acids is a saccharide chosen from monosaccharides, disaccharides, oligosaccharides, polysaccharides and mixtures thereof.

[0059] The monosaccharide may be chosen 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, as well as pentoses such as xylose, arabinose, ribose, ribulose, lyxose and xylulose.

[0060] The disaccharides may be chosen from sucrose, lactose and maltose, preferably sucrose.

[0061] By "oligosaccharides" is meant in the context of this description compounds containing from 3 to 8 monosaccharide units in the form of aldoses and / or ketoses, such as raffinose, manninotriose, stachyose and verbascose.

[0062] Examples of polysaccharides are arabinan, galactan, glucan, manan and xylan.

[0063] The 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) may be mentioned, as well as cellulose and / or hemicellulose hydrolysates, 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, corn, rye, rice, barley, millet, oats, sorghum, chestnuts or hazelnuts.

[0064] The saccharides used in the manufacture of the binder can be chosen from reducing sugars, non-reducing sugars and hydrogenated sugars.

[0065] By "hydrogenated sugar" is meant 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.

[0066] 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.

[0067] 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.

[0068] The reducing sugars are preferably chosen 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.

[0069] The non-reducing sugars are preferably diholosides such as trehalose, isotrehaloses, sucrose, isosucroses and mixtures thereof. Sucrose is particularly preferred.

[0070] 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. 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.

[0071] 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. As binders based on these acids and alkanolamines, mention may in particular be made of 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 notably described in applications WO2004 / 007615 and WO2006 / 0061249.

[0072] Examples of polyols (other than hydrogenated sugars) used as coreactants 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.

[0073] Other co-reactants that may be mentioned include polyamines such as diethylenetriamine, triethylenetetramine or tetraethylenepentamine. Binders based on polycarboxylic acids and polyamines are described in particular in application US 2007 / 0173588.

[0074] 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.

[0075] 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 a 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.

[0076] Constituents other than those mentioned above may also be present in the binder. They may be derived from the sizing composition or from the reaction between components of the sizing composition and at least one of the coreactants described above and / or produced by heating components of the sizing composition. The sizing composition may in fact comprise at least one component chosen from: water; 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 (such as 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 advantageously being 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; and mixtures thereof.

[0077] In the method according to the present invention, an insulating material comprising a binder as described previously is reacted with at least one amine.

[0078] The amine that can be used in the process according to the invention can be in liquid or gaseous form. It comprises at least one compound chosen from: ammonia; hydrazine; a primary or secondary hydrocarbon mono- or diamine, saturated or unsaturated, linear, branched or cyclic, optionally aromatic, the hydrocarbon chain of which contains from 1 to 20 carbon atoms and can optionally be substituted by at least one hydroxyl group and / or interrupted by at least one oxygen atom; and mixtures thereof.

[0079] Examples of monoamines are: ethylamine, propylamine, n-butylamine, sec-butylamine, 2-isobutylamine, tert-butylamine, pentylamine, hexylamine, tert-octylamine, cyclohexylamine, isophorylamine, benzylamine (aniline), xy-lylamine, tolylamine, aminoethanol, aminopropanol, and mixtures thereof.

[0080] As diamines, the following can be used: l-amino-3-aminomethyl-3,5,5-trimethyl cyclohexane (IPDA), bis-(4-aminocyclohexyl)-methane, bis-(4-amino-3-methylcyclohexyl)methane, 1,6-diamino hexane, 2-methyl penta-methylene diamine, ethylene diamine, 1,2- and 1,3-propanediamines, 2-methyl-1,2-propanediamine, 2,2-dimethyl-1,3-propanediamine, 1,3- and 1,4-butanediamines, 1,3- and 1,5-pentanediamines, 2-methyl-1,5-pentanediamine, 1,6-hexanediamine, 2,5-dimethyl-2,5-hexanediamine, 2,2,4- or 2,4,4-trimethyl-1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 2,4- and 2,6-hexahydrotoluylenediamines, 2,4'- and 4,4'-diamino-dicyclohexylmethanes, 1,3- and 1,4-cyclohexanediamines, 1,3- or 1,4-bis(methylamino)-cyclohexane, 1,8-p-menthanediamine, phenylenediamine, 2,4- and 2,6-toluylenediamines, 2,3- and 3,4-toluylenediamines, o-, m- or p-xylylenediamines, 2,4'- and 4,4'-diaminodiphenylmethanes, guanidine, N-(2-aminoethyl)-1,3-propanediamine, benzidine, N,N'-di-(2-aminoethyl)piperazine and mixtures thereof.

[0081] The diamine may also be a polyetheramine. A polyetheramine is a polyamine comprising ether bonds (-O-), more particularly ethylene oxide (-O-CH2-CH2) and / or propylene oxide (-O-CH2-CHCH3-) units.

[0082] Examples of polyetheramines are the compounds marketed by Hunstmann under the reference Jeffamine®, in particular the Jeffamine® D, ED and EDR series. These series include in particular the following references Jeffamine®D-230, Jeffamine® D-400, Jeffamine® D-2000, Jeffamine® D-4000, Jeffamine® ED-600, Jeffamine® ED-900, Jeffamine® ED-2003, Jeffamine® EDR-148, Jeffamine® EDR-176.

[0083] According to the invention, it is preferred to use a monoamine, in particular aminopropanol.

[0084] In this description, the term "amine" refers to both a single amine and a mixture of amines.

[0085] The insulating material may be brought into contact with the amine by any means enabling the entire material to be treated to be brought into contact with the amine and in particular, in the case where the amine is in the gaseous phase, by passing the amine into a container containing the material and, in the case where the amine is in the liquid phase, by dipping, spraying or coating, preferably by immersing the insulating material in a solution containing, or consisting of, the amine. When the amine is in the liquid phase, it may optionally be mixed with an organic solvent and / or water, although it is preferred not to use organic solvents. The contacting of the insulating material with the amine can be carried out at a temperature of -20 to 250°C and is preferably carried out at the boiling temperature of the amine, for a period ranging for example from 1h to 48h, preferably from 2h to 30h.

[0086] The method according to the invention may further comprise steps of recovering the material treated with the amine, washing, preferably with water or with an aqueous solution, and drying, in order to obtain mineral fibers, which may then be reused in the manufacture of an insulating material, possibly after carding.

[0087] The reaction product is then washed with water and dried to recover the fibers which can be reused in the manufacture of a new insulating material, possibly after a carding step. FIGURES

[0088] [Fig. 1] represents the evolution of the appearance of a sample of glass wool containing a binder based on phenolic resin, after hydrolysis (water) or aminolysis (ethylene diamine).

[0089] [Fig.2] illustrates the results of mechanical tests carried out on a sample of canvas glass containing a phenolic resin binder, before and after aminolysis.

[0090] [Fig.3] illustrates the results of mechanical tests carried out on a sample of canvas glass containing a polyester-based binder, before and after aminolysis.

[0091] [Fig.4] represents the evolution of the appearance of a glass wool sample, containing a binder based on Maillard reagents, after aminolysis (3-amino-1-propanol).

[0092] [Fig.5] illustrates the results of mechanical tests carried out on a sample of canvas glass containing a binder based on saccharide and ammonium salt of inorganic acid, and after aminolysis.

[0093] [Fig.6] illustrates the variation in appearance and diameter of a glass fiber subjected to a aminolysis process. EXAMPLES

[0094] The following examples illustrate the invention without, however, limiting it.

[0095] EXAMPLE 1: Decomposition of a phenolic resin-based binder

[0096] Tests were carried out on a glass wool sample comprising biosoluble glass fibres and a phenolic resin binder as described in patent application WO2008 / 043961. Approximately 2g of this sample was placed in a flask and covered with 55g of ethylenediamine which was refluxed (130°C) for approximately 24h. For comparison, another identical sample was placed in refluxing water (100°C) for approximately 24h. After 24h, the samples were washed with water and dried by vacuum filtration. Photographs of the treated and untreated samples are shown in [Fig.l]. As can be seen from this figure, the treated sample by aminolysis appears whiter, due to the decomposition of the phenolic resin that gave it an initial yellow appearance. In contrast, the sample treated by hydrolysis remains yellow-orange, suggesting that hydrolysis is not sufficient to decompose the binder. Scanning electron microscope (SEM) analysis also observed that the hydrolyzed sample still has traces of binder between the fibers, identified by a circle, while no binder was identified between the fibers treated by aminolysis, which appear disentangled.

[0097] To confirm these observations, a tensile test was carried out on samples treated by aminolysis, on the one hand, and untreated, on the other hand. To do this, a test piece was taken from a sample of glass cloth coated with the binder described above, then the test piece was suspended from an aluminum rod in a reactor in which the amine was refluxed. After aminolysis, the test piece was dried and then subjected to a tensile test carried out at 1 mm / min on a Shimadzu EZ LX tensile bench with an ION force sensor. The same test was carried out on untreated test pieces taken from the same sample.

[0098] As illustrated in [Fig.2], the force required to separate the fibers was very low, which reflected sliding of the fibers over each other. The breaking stress and Young's modulus of the treated sample were also very low.

[0099] EXAMPLE 2: Decomposition of a polyester-based binder

[0100] A tensile test identical to that described in Example 1 was carried out on a sample of glass wool comprising glass fibers and a polyester-based binder resulting from the reaction of citric acid with sugars as described in patent application WO2013 / 014399, respectively subjected to an aminolysis process or not().

[0101] The results of the tensile test carried out are presented in [Fig.3].

[0102] As can be seen from this Figure, the force required to separate the glass fibers is very low, reflecting degradation of the polyester-based binder. The breaking stress and Young's modulus of the treated sample were also very low.

[0103] EXAMPLE 3: Decomposition of a binder based on Maillard reagents

[0104] Tests were carried out on glass wool comprising fibers of glass and a plant-based binder (Ecose® from KNAUF) comprising a thermoset resin prepared by the Maillard reaction between a saccharide and an amino compound. A sample of approximately 2g was placed in a flask and covered with 55g of aminopropanol, which was refluxed (185°C) for approximately 24 hours. After 24 hours, the sample was washed with water and dried by vacuum filtration. A photograph of the treated sample is shown in [Fig.4]. As can be seen from this figure, aminolysis made the sample whiter, due to the decomposition of the Maillard reaction products that gave it an initial brown appearance.

[0105] Additional tests were carried out by replacing the aminopropanol with ethylene diamine, on the one hand, and the glass fibers with rock fibers, on the other hand: the same observations could be made.

[0106] EXAMPLE 4: Decomposition of a binder based on sucrose and ammonium salt of inorganic acid

[0107] A tensile test was carried out on a test piece from a glass wool sample comprising a self-crosslinked sugar-based binder, resulting from the reaction of sucrose with ammonium sulfate, in a sucrose / ammonium sulfate ratio of 85 / 15.

[0108] The conditions of the test described in Example 1 were modified so as to subject the sample to aminolysis using aminopropanol vapors and not by immersion in diethylamine. To do this, a small amount of amine was placed at the bottom of a flask above which the sample was suspended using a metal wire. The strain / stress curves obtained are illustrated in [Fig.5]. As shown in this Figure, the test piece exhibits no mechanical resistance after aminolysis, which reflects the effectiveness of this treatment in breaking down the binder tested. The breaking stress and Young's modulus of the treated sample were also very low.

[0109] EXAMPLE 5: Decomposition of a binder based on poly(furfuryl alcohol)

[0110] A sample of glass wool comprising a binder based on poly(furfuryl alcohol) from sugarcane bagasse (Biorez® from TransFuran Chemical) and high alumina glass fibers.

[0111] Approximately 2g of this sample was immersed in a flask containing aminopropanol which was refluxed for approximately 24 hours. Photographs of the sample were taken before and after treatment: a change in color of the sample was observed which highlighted the degradation of the binder.

[0112] EXAMPLE 6: Evaluation of the preservation of fiber quality

[0113] The impact of aminolysis treatment on fiber quality was evaluated using glass fibers and high alumina (HA) fibers, respectively.

[0114] To do this, glass fibers as described in WO2005 / 033032, approximately 500-600 μm in diameter and 4 cm in length, were immersed in refluxing ethylene diamine for 24 hours. The general appearance of the fibers before and after treatment was observed and their average diameter was measured: no modification was observed.

[0115] The THA fibers were subjected to an aminolysis treatment using aminopropanol in which they were partially immersed, in order to simultaneously evaluate the effect of liquid and gaseous aminopropanol. The diameter of the fibers was measured before and after treatment. It was observed that the diameter of the immersed part of the fiber, subjected to liquid aminopropanol, had decreased by 5% during the aminolysis treatment. On the contrary, the diameter of the emerged fiber part, treated by aminopropanol vapors, was unchanged. This example thus demonstrates that vapor-phase aminolysis preserves fiber quality better than liquid-phase aminolysis. It is thus possible to reuse the fibers in the manufacture of a new glass wool product.

Claims

Claims

1. A method of recycling an insulating material in the form of a mineral wool mattress or felt containing mineral fibers which represent from 80 to 99% of the weight of the insulating material and a binder comprising at least one thermoset resin, said method comprising a step of bringing said insulating material into contact with at least one amine in liquid or gaseous form, for a time sufficient to decompose said binder.

2. Method according to claim 1, characterized in that the binder comprises a phenolic resin optionally modified with an amine, in particular an aminated phenolic resin consisting essentially of phenol-formaldehyde condensates and phenol-formaldehyde-amine condensates.

3. Method according to claim 1, characterized in that the binder comprises the product of the reaction between compounds comprising: - at least one saccharide chosen from monosaccharides, disaccharides, oligosaccharides, polysaccharides and mixtures thereof, and / or - at least one polycarboxylic acid chosen from monomeric and polymeric carboxylic acids, or an anhydride of such an acid.

4. Method according to claim 3, 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 mixtures thereof; at least one alkanolamine; at least one polyol other than a saccharide; at least one polyamine; and mixtures thereof, 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.

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

6. Method according to claim 3, characterized in that the saccharide is a reducing sugar and the binder is the product of the reaction of said at least a 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 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.

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

8. Process according to any one of claims 1 to 7, characterized in that the amine in liquid or gaseous form is chosen from: ammonia; hydrazine; a primary or secondary hydrocarbon mono- or diamine, saturated or unsaturated, linear, branched or cyclic, optionally aromatic, the hydrocarbon chain of which contains from 1 to 20 carbon atoms and may optionally be substituted by at least one hydroxyl group and / or interrupted by at least one oxygen atom; and mixtures thereof.

9. Method according to any one of claims 1 to 8, characterized in that the contacting of the insulating material and the amine is carried out by immersing the insulating material in a solution containing, or consisting of, the amine, preferably at the boiling temperature of the amine.

10. Method according to any one of claims 1 to 8, characterized in that the amine is in gaseous form and the contacting of the insulating material and the amine is preferably carried out by passing the amine into a container containing the insulating material.

11. A method according to any one of claims 1 to 10, characterized in that it further comprises steps of recovering the material treated with the amine, washing, preferably with water or with an aqueous solution, and drying, in order to obtain mineral fibers.

12. Method according to claim 11, characterized in that the recovered mineral fibers are reused in the manufacture of an insulating material, possibly after carding.

13. Use of an amine as defined in claim 1 or 8 for decomposing the binder contained in an insulating material in the form of a mineral wool mat or felt containing fibers minerals which represent 80 to 99% of the weight of the insulating material and a binder comprising at least one thermoset resin.

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