Soundproofing product

Abstract

The present invention relates to a method for producing a fibre-based soundproofing product, which comprises: - providing fibres; - applying a binder composition comprising raw materials necessary for forming an infusible binder to the fibres in order to form an assembly of glued fibres; and - heating the assembly of glued fibres to a temperature that allows the evaporation of the water and the formation of an infusible binder, wherein a film-forming agent is applied to the fibres before, simultaneously with or after the binder composition. The invention also relates to a soundproofing product comprising an assembly of fibres bound by an infusible binder and by a film-forming agent.

Description

[0001] Description

[0002] Title: ACOUSTIC INSULATION PRODUCT

[0003] The present invention relates to the field of acoustic insulation products. More particularly, the present invention relates to a method for manufacturing an acoustic insulation product comprising in particular the application of a binder and a film-forming agent to fibers. It also relates to the acoustic insulation product obtainable by such a method, which comprises an assembly of fibers bound by an infusible binder and by a film-forming agent.

[0004] TECHNOLOGICAL BACKGROUND

[0005] Noise affects everyone. It's everywhere: in the street, on construction sites, in train stations or airports, but also in our homes. This phenomenon, particularly familiar to city dwellers, can lead to a number of pathologies such as sleep disorders, stress, or loss of concentration. Acoustic comfort is an essential element of quality of life. To best meet this expectation, the Applicant has been conducting research and development efforts in this area for many years.

[0006] In particular, it has developed products for acoustic insulation based on bonded mineral wool, generally presented in the form of mattresses, sails, slabs, or panels. These products find their application in the acoustic insulation of walls, partitions, metal cladding, pitched roofs, warm roofs, waterproof roofs, ceilings, floors and floors, or even in air conditioning and air ducts. These products can also be used in the transport sector.

[0007] The acoustic properties of a mineral wool product are closely linked to its microstructure. It is possible to act on various parameters, such as fiber density and diameter, to improve the acoustic properties. These parameters have a particular impact on the specific air resistance, which is a key parameter controlling sound absorption. Despite the improvements made to date, mineral wool products maintain low values ​​of specific air resistance, especially those with low density.

[0008] There is therefore a real need to provide a mineral wool product with improved sound insulation properties. In particular, it would be advantageous to have a product with an improved specific air flow resistance (abbreviated AFR), in order to obtain better sound absorption performance, and / or with an acoustically identical performance at reduced thickness or density.

[0009] SUMMARY OF THE INVENTION

[0010] In this context, the inventors discovered that the addition of a film-forming agent, before, simultaneously with, or after the addition of the binder composition used to glue the fibers, made it possible to significantly improve the specific resistance to the passage of air, and therefore the acoustic properties of the product. This development is particularly advantageous for the manufacture of lightweight products, having a low density, and of low thickness.

[0011] Thus, the present invention relates to a method for manufacturing a fiber-based acoustic insulation product comprising:

[0012] - the supply of fibers;

[0013] - applying to the fibers a binder composition comprising raw materials necessary for the formation of an infusible binder (and typically water), to form an assembly of glued fibers; and

[0014] - heating the assembly of glued fibers, to a temperature allowing the formation of an infusible binder (and typically the evaporation of water), in which a film-forming agent is applied to the fibers before, simultaneously with or after said binder composition.

[0015] In some embodiments, the film-forming agent is selected from polyvinyl alcohol, polyethylene, polyacrylate, polyacrylic acid, starch, cellulose and its derivatives, polyvinyl butyral, polyvinyl acetate, polyvinylpyrrolidone, chitosan, polypeptides, polysorbates, fatty acids, polyamino acids, glycol esters, glycerol esters, sorbitan esters, and a mixture of at least two thereof. Preferably, the film-forming agent is polyvinyl alcohol.

[0016] In certain embodiments, the mass ratio of the amount of film-forming agent to the amount of fibers is between 0.005 and 0.2, preferably between 0.005 and 0.1, or even between 0.005 and 0.06, or even between 0.005 and 0.03.

[0017] In some embodiments, the mass ratio of the amount of said raw materials required for forming an infusible binder (included in the binder composition) to the amount of fibers is between 0.005 and 0.2, preferably between 0.01 and 0.15, or even between 0.01 and 0.1, or even between 0.02 and 0.07. In some embodiments, the mass ratio of the amount of said raw materials required for forming an infusible binder to the amount of film-forming agent is between 0.1 and 4, preferably between 0.1 and 3, or even 0.1 and 1.5, in particular between 0.1 and 1, for example between 0.4 and 1.

[0018] In some embodiments, the film-forming agent is applied to the fibers after said binder composition and preferably before the step of heating the sized fiber assembly. In some embodiments, said binder composition comprises a polyol and a polycarboxylic acid, an ester, anhydride, or salt thereof, or an oligoester thereof. The polyol is preferably a sugar, or even a reducing sugar, a non-reducing sugar, a hydrogenated sugar, or a mixture thereof.

[0019] In certain embodiments, the film-forming agent has a glass transition temperature of less than or equal to 140°C, preferably between -50°C and 140°C, or even between -50°C and 45°C.

[0020] In some embodiments, the fibers are mineral fibers optionally mixed with thermoplastic fibers.

[0021] In some embodiments, the fiber assembly is a mineral wool, including a glass wool or a rock wool.

[0022] In some embodiments, said binder composition and the film-forming agent, in the form of an aqueous composition, are applied by spraying.

[0023] In certain embodiments, the heating step is carried out at a temperature greater than or equal to 100°C, preferably greater than or equal to 120°C, or even greater than or equal to 140°C, and generally less than 250°C.

[0024] The present invention also relates to an acoustic insulating product comprising an assembly of fibers bound by an infusible binder and by a film-forming agent, in which the mass ratio of the quantity of film-forming agent to the quantity of fibers is advantageously between 0.005 and 0.2. Preferably, said film-forming agent is polyvinyl alcohol.

[0025] DETAILED DESCRIPTION

[0026] The method according to the invention comprises providing fibers. Said fibers may be mineral fibers, organic fibers or a mixture thereof. Organic fibers include in particular natural organic fibers such as wood fibers and synthetic organic fibers, such as thermoplastic fibers. In a particular embodiment, the fibers comprise (preferably consist of) mineral fibers. In such an embodiment, the mineral fibers represent at least 10%, for example at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 80%, or at least 90%, and preferably at most 99.5%, of the total weight of fibers.

[0027] In a particular embodiment, the fibers are mineral fibers mixed with thermoplastic fibers.

[0028] Preferably, the fibers are mineral fibers, in particular mineral wool fibers, more particularly glass wool or rock wool fibers. By "mineral wool fibers", "glass wool fibers" and "rock wool fibers" is meant fibers suitable, in particular in terms of diameter and length, for the formation of mineral, glass and rock wool respectively.

[0029] Preferably, the assembly of fibers is a mineral wool, in particular a glass or rock wool.

[0030] When the fiber assembly is glass wool, it advantageously has a micronaire of between 9 and 26 L / min. Preferably, said micronaire is between 12 and 24 L / min, or even between 14 and 20 L / min.

[0031] The micronaire is representative of the fineness of the fibers in the glass wool. The micronaire measurement accounts for the specific surface area by measuring the aerodynamic pressure drop when a given quantity of fibers extracted from an unsized mat is subjected to a given pressure of a gas - generally air or nitrogen. This measurement is common in mineral fiber production units, it is carried out according to the DIN 53941 or ASTM D 1448 standard and uses a device called a "micronaire device".

[0032] When the assembly of fibers is rock wool, it advantageously has a fasonaire of at least 100, or even at least 200, for example between 200 and 300. Preferably, said fasonaire is between 200 and 290, or even between 200 and 280, or even between 200 and 270.

[0033] The fasonaire is representative of the fineness of rock fibers. The fasonaire measurement is a determination of the fiber fineness index by a method similar to that of the micronaire according to the standards ASTM-D-1448 or DIN 53941. The fasonaire is equal to the pressure drop or difference in flow rate of a gas stream passing through a test piece consisting of a tuft of mineral fibers of given mass (equal to 5 g for the measurements according to the invention). The tuft of fibers, free of binder or any other non-fibrous component, is compressed in a cylindrical chamber of predetermined volume. With the gas flow rate kept constant, the pressure drop across the test piece is measured using a water column graduated in conventional units called fasonaires. The fasonaire is thus expressed in millimeters of water column per 5 g (mass of the test piece).

[0034] When the fibers are synthetic fibers, such as thermoplastic fibers, these preferably have a Dtex of 1 to 20 and a length of 3 to 25 mm.

[0035] The method according to the invention comprises the application to the fibers of:

[0036] (i) a binder composition comprising raw materials necessary for the formation of an infusible binder, and

[0037] (ii) a film-forming agent.

[0038] Said film-forming agent is applied before, simultaneously with or after said binder composition.

[0039] The film-forming agent is preferably distinct from the raw materials of said binder composition. In particular, the film-forming agent is advantageously a chemical compound different from the chemical compounds that constitute the raw materials of the binder composition. It is preferred that said raw materials of said binder composition do not comprise a component that is a film-forming agent.

[0040] The binder composition is typically an aqueous composition which therefore includes water and raw materials necessary for the formation of an infusible binder.

[0041] The raw materials required for the formation of an infusible binder, in the field of fiber binders, are well known to those skilled in the art.

[0042] In one embodiment, the raw materials of the binder composition comprise:

[0043] - a polyol and a polycarboxylic acid, an ester, anhydride, or salt of this acid, or

[0044] - an oligoester thereof.

[0045] In such an embodiment, the polyol advantageously represents 10 to 80% of the weight of the mixture consisting of the polyol and the polycarboxylic acid, preferably at least 20%, in particular 20 to 90%, advantageously at least 30%, and better still from 30 to 80%.

[0046] “Polyol” refers to any organic compound having at least two -OH functions. It is preferred that the polyol is not PVA. More generally, it is preferred that the polyol is not a film-forming polyol. Advantageously, the polyol is a sugar, which is preferably selected from a reducing sugar, a non-reducing sugar, a hydrogenated sugar, and a mixture thereof. In the present application, the term “sugar” has a broader meaning than usual, since it encompasses not only sugars in the strict sense, i.e. reducing sugars or carbohydrates of formula Cn(H2O)p where p = n (monosaccharides) or p = n-1 (oligo- and polysaccharides) having at least one aldehyde or ketone group (reducing group), but also the hydrogenation products of these sugars, called hydrogenated sugars.The term sugar also includes non-reducing sugars consisting of several carbohydrate units whose carbons carrying the hemiacetalic hydroxyl are involved in the osidic bonds linking the units together.

[0047] The reducing sugars are preferably selected from monosaccharides such as glucose, galactose, mannose and fructose, disaccharides such as lactose, maltose, isomaltose and cellobiose, and the starch or lignocellulosic hydrolysates described above. In some embodiments, the sugar is glucose and fructose, particularly glucose.

[0048] Non-reducing sugars are preferably disaccharides such as trehalose, isotrehaloses, sucrose and isosucroses. Sucrose is particularly preferred.

[0049] By "hydrogenated sugar" is meant in the present invention a product 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. In certain embodiments, the hydrogenated sugar has a number average molar mass of less than 100,000 g / mol, preferably less than 50,000 g / mol, advantageously less than 5,000 g / mol, and better still greater than 180 g / mol.

[0050] The hydrogenation of the saccharide can be carried out by known methods operating under conditions of high hydrogen pressure and temperature, in the presence of a catalyst selected from the elements of groups IB, IIB, 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. The hydrogenation transforms the sugar or mixture of sugars (starch hydrolyzate) into polyols or sugar alcohols.

[0051] The hydrogenated sugar(s) are preferably selected from the group consisting of erythritol, arabitol, xylitol, sorbitol, mannitol, iditol, maltitol, isomaltitol, lactitol, cellobitol, palatinitol, maltotritol, and hydrogenation products of starch hydrolysates or hydrolysates of lignocellulosic materials, in particular hemicellulose, in particular xylans and xyloglucans. Starch hydrolysates are products obtained by enzymatic and / or acid hydrolysis of starch. The degree of hydrolysis is generally characterized by the dextrose equivalent (DE), defined by the following relationship: DE = 100 x (number of glycosidic bonds broken / number of glycosidic bonds in the initial starch).

[0052] Preferred starch hydrolysates have, before the hydrogenation step, a DE of between 5 and 99, and advantageously between 10 and 80.

[0053] In a particular embodiment, the sugar is a hydrogenated sugar selected from the group consisting of maltitol, xylitol, sorbitol and the hydrogenation products of starch hydrolysates or lignocellulosic materials.

[0054] By “polycarboxylic acid” is meant an organic acid comprising at least two carboxylic functions, preferably at most 300, advantageously at most 70, and better still at most 15 carboxylic functions.

[0055] The polycarboxylic acid may be a monomeric (i.e. non-polymeric) or polymeric acid. It has a number-average molar mass generally less than or equal to 50,000 g / mol, preferably less than or equal to 10,000 g / mol and advantageously less than or equal to 5,000 g / mol.

[0056] The non-polymeric polycarboxylic acid may in particular be an alicyclic acid, branched or not, saturated or unsaturated, a cyclic acid or an aromatic acid.

[0057] The non-polymeric polycarboxylic acid may be a dicarboxylic acid, for example 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 and its derivatives, in particular containing at least one boron or chlorine atom, tetrahydrophthalic acid and its derivatives, in particular containing at least one chlorine atom such as chlorendic acid, isophthalic acid, terephthalic acid, mesaconic acid and citraconic acid; a tricarboxylic acid, for example citric acid, tricarballylic acid, 1,2,4-butanetricarboxylic acid, aconitic acid, hemimellitic acid, trimellitic acid and trimesic acid;a tetracarboxylic acid, for example 1,2,3,4-butanetetracarboxylic acid and pyromellitic acid, preferably the non-polymeric polycarboxylic acid is citric acid.;

[0058] Examples of polymeric polycarboxylic acids include homopolymers of unsaturated carboxylic acids such as (meth)acrylic acid, crotonic acid, isocrotonic acid, maleic acid, cinnamic acid, 2-methylmaleic acid, fumaric acid, itaconic acid, 2-methylitaconic acid, α,β-methyleneglutaric acid and unsaturated dicarboxylic acid monoesters, such as C1-C10 alkyl maleates and fumarates, and copolymers of at least one aforementioned unsaturated carboxylic acid and at least one vinyl monomer such as styrene substituted or not by alkyl, hydroxyl or sulfonyl groups, or by a halogen atom, (meth)acrylonitrile, (meth)acrylamide or not by C1-C10 alkyl groups, alkyl (meth)acrylates, in particular methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate and isobutyl (meth)acrylate, glycidyl (meth)acrylate,butadiene and a vinyl ester, especially vinyl acetate.,

[0059] In certain embodiments, the binder composition comprises at least one non-polymeric polycarboxylic acid having a number-average molar mass less than or equal to 1000 g / mol, preferably less than or equal to 750 g / mol and advantageously less than or equal to 500 g / mol, optionally in admixture with at least one polymeric acid.

[0060] In a preferred embodiment, the polycarboxylic acid is citric acid.

[0061] In some embodiments, the raw materials of the binder composition comprise an oligomeric ester (also referred to as an "oligoester") of a polyol (especially a sugar) and a polycarboxylic acid (or an ester, anhydride, or salt thereof). In such an embodiment, the binder composition preferably comprises at least 80% by weight, more preferably at least 85% by weight, or even at least 90% by weight, based on its total solids content, of oligomeric ester.

[0062] These oligomeric esters, which can be obtained by polycondensation of polyol and polycarboxylic acid, have the advantage of significantly limiting the emissions of volatile acid components at the chimney of a curing oven. Oligomeric esters are water-soluble and stable in water at room temperature, form infinitely pumpable and dilutable aqueous solutions and, at the concentrations commonly used for binder compositions, have viscosities that are perfectly compatible with a conventional spray sizing system using nozzles (spray crown).

[0063] Polycondensation is generally carried out by mixing the above-mentioned reagents, in an essentially anhydrous medium (e.g. less than 2% water, preferably less than 1% water in the mixture), in the presence of an esterification catalyst (e.g. sulfuric acid, hydrochloric acid, para-toluenesulfonic acid, trifluoromethanesulfonic acid, trifluoroacetic acid, Lewis acids commonly used for the catalysis of esterification reactions, sodium hypophosphite, hypophosphorous acid, or a mixture thereof) and at a temperature between 105°C and 170°C, or even between 120 and 150°C. The binder composition may then be formed by adding water, either directly to the mixture comprising the freshly formed oligomeric ester or to a previously stored concentrated aqueous solution of the oligomeric ester, in an amount to achieve a viscosity suitable for application to the fibers.When the raw materials of the binder composition comprise the oligomeric ester, it is preferable that the binder composition comprises less than 20% by weight, or even less than 10% by weight, and in particular less than 5% by weight, based on the total solids content, of free residual polycarboxylic acid.

[0064] In some embodiments, the raw materials of the binder composition comprise a polyol and a polyaldehyde. By "polyaldehyde" is meant an aldehyde comprising at least two aldehyde functionalities. Preferably, the polyaldehyde is a non-polymeric dialdehyde, for example glyoxal, glutaraldehyde, 1,6-hexanedial or 1,4-terephthalic dialdehyde.

[0065] To improve the stability and / or prevent pre-gelling of a sizing composition comprising a polyaldehyde, the aldehyde functions of the polyaldehyde are advantageously blocked to prevent reaction with the constituents present in the sizing composition before the mineral wool enters the oven. Examples of agents that allow the blocking of aldehyde functions include urea and cyclic ureas.

[0066] In some embodiments, the raw materials of the binder composition comprise a reducing or non-reducing (preferably reducing) sugar and a nitrogen compound. The nitrogen compound is in particular an ammonium salt of an inorganic acid (e.g., phosphoric, sulfuric, nitric, or carbonic acid) or a polyamine. The term "polyamine" means an organic compound having at least two amine functions, such as a diamine, triamine, or tetraamine. The amine functions may be primary, secondary, tertiary, and quaternary amine functions. Examples of polyamines include 1,6-diaminohexane, 1,5-diamino-2-methylpentane, diethylenetriamine, 1-piperazineethaneamine, bis(hexamethylene)triamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine (PEI), polyvinylamine, a polyetheramine, or polylysine.In a particular embodiment, the polyamine is of formula H2N-R-NH2 where R is alkyl, cycloalkyl, heteroalkyl, or cycloheteroalkyl, each of which is optionally substituted. The mass ratio of reducing or non-reducing sugar to nitrogen compound is preferably between 2 and 15.

[0067] In some embodiments, the raw materials of the binder composition comprise a furfuryl alcohol oligomer (also called poly(furfuryl alcohol) or more generally furan resin), and optionally a reducing or non-reducing sugar (or a mixture of the two sugars). Generally, when a sugar is present, the proportions are as follows: 40 to 95% by weight of furan resin and 5 to 60% by weight of reducing and / or non-reducing sugar, based on the total dry weight of the binder composition.

[0068] In some embodiments, the raw materials of the binder composition comprise a phenolic resin. Phenolic resin (also referred to as "resol") is a thermosetting resin typically obtained by condensation of phenol and formaldehyde, and optionally in the presence of other components, in particular to adjust the properties of the resin. These components may, for example, be glycine, urea, an amine, or an amino alcohol. Alternatively, the aforementioned components may be added as raw materials to the binder composition comprising the phenolic resin (i.e., after formation of said phenolic resin).

[0069] In some embodiments, the raw materials of the binder composition comprise:

[0070] - a lignin, and

[0071] - a reactive component chosen from a sugar, a polycarboxylic acid (preferably non-polymeric), an aldehyde and a ketone. The aldehyde may in particular be a compound of formula RC(O)H where R represents a hydrocarbon radical, linear, branched or cyclic, saturated or unsaturated, a radical containing one or more aromatic rings consisting of 5 or 6 carbon atoms, a radical containing one or more aromatic heterocycles containing 4 or 5 carbon atoms and an oxygen, nitrogen or sulfur atom, the radical R possibly containing other functional groups, in particular hydroxyl or alkoxy, in particular methoxy.

[0072] The ketone may in particular be a compound of formula RC(O)-R' where R is as defined above for the aldehyde and R' is a C1-C10 alkyl.

[0073] The lignin may be chosen from alkaline lignins (also called Kraft lignins), lignosulfonates (e.g. ammonium lignosulfonates, or an alkali or alkaline earth metal salt of lignosulfonic acid), organosolv lignins, sodium lignins, lignins from biorefining processes of lignocellulosic raw materials or a mixture thereof.

[0074] Lignin generally represents 10 to 90% (for example, 20 to 80% or 30 to 70%) of the weight of the mixture consisting of lignin and said reactive component.

[0075] In some embodiments, the raw materials of the binder composition comprise an acrylic resin. In some embodiments, the raw materials of the binder composition comprise an alkyd resin.

[0076] In some embodiments, the raw materials of the binder composition comprise a polyurethane resin. The polyurethane resin is typically obtained from a polyol and a polyisocyanate.

[0077] In some embodiments, the raw materials of the binder composition comprise a urea-formaldehyde resin. The urea-formaldehyde resin is a thermosetting resin typically obtained by condensation of urea and formaldehyde.

[0078] In addition to the raw materials necessary for the formation of an infusible binder, the binder composition may further comprise one or more additives and / or fillers. These additives and / or fillers are chosen from those conventionally used commonly in the technical field of fiber-based insulation products. These additives and / or fillers may be chosen, for example, from anti-dust additives, silicones, coupling agents (e.g., a silane) and “extenders”. An “extender” is an organic filler that is soluble or dispersible in the binder composition, which in particular makes it possible to reduce the cost thereof.

[0079] The binder composition may further comprise a catalyst, acid or basic, which has the function in particular of adjusting the temperature at which crosslinking begins.

[0080] The catalyst may be selected from Lewis bases and acids, such as clays, colloidal or non-colloidal silica, organic amines, quaternary amines, metal oxides, metal sulfates, metal chlorides, urea sulfates, urea chlorides, and silicate catalysts. The catalyst may also be a phosphorus-containing compound, 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. Preferably, the alkali metal is sodium or potassium.The catalyst may also be a compound containing fluorine and boron, for example tetrafluoroboric acid or a salt thereof, including 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, the catalyst is sodium hypophosphite, sodium phosphite, and mixtures of these compounds. The amount of catalyst introduced into the binder composition may be up to 20% of the weight of the hydrogenated sugar and the polyfunctional crosslinking agent, preferably up to 10%, and advantageously is at least 1%.

[0081] In the present application, additives, fillers and catalysts are not included in said raw materials necessary for the formation of an infusible binder. Said raw materials necessary for the formation of an infusible binder include the compounds which react together to form the polymer network. Although a portion of the film-forming agent may, in certain cases (for example, this may occur when the film-forming agent is applied simultaneously or immediately after the application of said raw materials), during the implementation of the process, react with said raw materials necessary for the formation of an infusible binder, it is not included in said raw materials necessary for the formation of an infusible binder.

[0082] The weight content of raw materials necessary for the formation of an infusible binder (in solids) in the binder composition is generally between 1 and 25%, preferably between 2 and 15%, or even between 2 and 10%, or even between 2 and 8% (i.e. relative to the total weight of the composition).

[0083] The proportion of additives, fillers and catalysts is generally low compared to said raw materials. Thus, the solids content by weight of the binder composition is generally of the same order as the solids content by weight of raw materials necessary for the formation of an infusible binder. In certain embodiments, the solids content by weight of the binder composition is between 1 and 25%, preferably between 2 and 15%, or even between 2 and 10%, or even between 2 and 8% (i.e. relative to the total weight of the composition).

[0084] In the process according to the invention, the mass ratio of the quantity of said raw materials necessary for the formation of an infusible binder to the quantity of fibers is advantageously between 0.005 and 0.2, preferably between 0.01 and 0.15, or even between 0.01 and 0.1, or even between 0.02 and 0.07.

[0085] By "film-forming agent" is meant a compound having a minimum film formation temperature (MFFT), the latter generally being less than or equal to 100°C, advantageously less than or equal to 90°C, preferably less than or equal to 70°C, better still less than or equal to 30°C, or even less than or equal to 20°C, or even less than or equal to 10°C and in particular less than or equal to 0°C. The MFFT is determined according to the standards ASTM D 2354 and ISO 2115. The MFFT is given here for atmospheric pressure (i.e. 1 bar).

[0086] The glass transition temperature (Tg) of the film-forming agent is advantageously less than or equal to 140°C, for example between -50°C and 140°C, between -40°C and 120°C, between -20°C and 100°C, or between 0°C and 80°C. Preferably, the Tg of the film-forming agent is less than 90°C, for example between 5°C and 90°C, between 10°C and 80°C, between 15°C and 60°C or between 20°C and 50°C. In certain embodiments, the Tg of the film-forming agent is less than or equal to 45°C, preferably between -50°C and 45°C, or even between -20°C and 45°C.

[0087] The glass transition temperature can be measured by differential scanning calorimetry (DSC).

[0088] The film-forming agent is typically an organic polymer. When the film-forming agent is an organic polymer, the molecular weight thereof is not particularly limited. The weight-average molecular weight (generally determined by light scattering) may, for example, be between 1,000 and 200,000 g / mol, preferably between 5,000 and 100,000 g / mol, or even between 10,000 and 80,000 g / mol.

[0089] Examples of film-forming agents include polyvinyl alcohol (PVA), polyethylene, polyacrylate, polyacrylic acid, starch, cellulose and its derivatives, polyvinyl butyral (PVB), polyvinyl acetate, polyvinylpyrrolidone (PVP), chitosan, polypeptides, polysorbates, fatty acids (eg a compound of formula RC(O)OM + where R is an aliphatic chain having 4 to 36 carbon atoms and M +is a cation (especially an alkali metal or an ammonium), polyamino acids, glycol esters, glycerol esters, sorbitan esters, or a mixture of at least two of these.

[0090] In some embodiments, the film-forming agent is a polyhydroxylated organic polymer.

[0091] Preferably, the film-forming agent is PVA.

[0092] PVA can be obtained in particular by partial or total hydrolysis of a polyvinyl acetate or a polyvinyl butyral.

[0093] The polyacrylate may in particular be a polyacrylate salt (in particular an alkali metal polyacrylate, such as sodium polyacrylate) and an alkyl polyacrylate (e.g. polymethyl acrylate). The film-forming agent may be applied to the fibers in solid or liquid form, pure or diluted. When in solid form, the film-forming agent may be in the form of fibers.

[0094] Preferably, it is applied in the form of a liquid composition (typically an aqueous solution) comprising the film-forming agent.

[0095] When in the form of a composition, the composition comprising the film-forming agent may comprise additives, in particular surfactants or complexing agents.

[0096] When it is in the form of a composition, the weight content of film-forming agent (in dry extract) in the composition is generally between 1 and 25%, preferably between 2 and 15%, or even between 2 and 10%, or even between 2 and 8% (i.e. relative to the total weight of the composition).

[0097] In the method according to the invention, the mass ratio of the quantity of film-forming agent to the quantity of fibers is advantageously between 0.005 and 0.2, for example between 0.01 and 0.15, between 0.01 and 0.1, or between 0.02 and 0.07. Preferably, the mass ratio of the quantity of film-forming agent to the quantity of fibers is between 0.005 and 0.1, or even between 0.005 and 0.06, or even between 0.005 and 0.03.

[0098] The mass ratio of the quantity of said raw materials necessary for the formation of an infusible binder to the quantity of film-forming agent is advantageously between 0.1 and 4, preferably between 0.1 and 3, or even 0.1 and 1.5, in particular between 0.1 and 1, for example between 0.4 and 1.

[0099] Unless otherwise indicated, the mass ratios are expressed in this application on the basis of the masses in dry extract (or equivalently “in solids”), e.g. dry extract in film-forming agent, dry extract in raw materials, etc.

[0100] Said raw materials necessary for the formation of an infusible binder generally comprise at least two different types of functions, these functions being reactive with each other (for example, COOH and OH). These reactive functions typically react with each other during the formation of the infusible binder.

[0101] The film-forming agent generally comprises functions which are reactive (under the conditions of implementation of the process) with respect to certain functions of said raw materials necessary for the formation of an infusible binder (for example, the film-forming agent may comprise OH functions). For the sake of conciseness and clarity, we will call:

[0102] - Fl, the functions of said raw materials necessary for the formation of an infusible binder with which the functions of the film-forming agent are reactive,

[0103] - F2, the functions of the film-forming agent reactive with the Fl functions; - F3, the functions of said raw materials necessary for the formation of an infusible binder which are reactive with the Fl functions.

[0104] Functions F2 and F3 can be the same or different.

[0105] The molar ratio Fl / (F2+F3) is:

[0106] - advantageously less than or equal to 0.7, or even less than or equal to 0.5, or even less than or equal to 0.45, and

[0107] - advantageously greater than 0.05, preferably greater than 0.1.

[0108] For example, the molar ratio Fl / (F2+F3) can be between 0.05 and 0.7, or even between 0.1 and 0.45.

[0109] The molar ratio Fl / F3 is:

[0110] - advantageously less than or equal to 2, preferably less than or equal to 1.5, or even less than or equal to 1, and

[0111] - advantageously greater than 0.1, preferably greater than 0.3, or even greater than 0.5.

[0112] For example, the Fl / F3 molar ratio can be between 0.1 and 1.5, preferably between 0.3 and 1.5, or even between 0.5 and 1.

[0113] In a particular embodiment, said raw materials comprise -OH and -COOH functions, and the film-forming agent comprises -OH functions. In such an embodiment, the COOH / OH molar ratio (i.e. "F1 / (F2+F3)") is advantageously between 0.05 and 0.7, preferably between 0.1 and 0.45.

[0114] The preparation of the binder composition is generally carried out by simply mixing said raw materials (and any additives, fillers, catalysts) with the solvent, which is typically water. When the film-forming agent is used in the form of a composition, the preparation of the composition comprising the film-forming agent is generally carried out by simply mixing the film-forming agent (and any additives) with the solvent, which is typically water.

[0115] The method according to the invention comprises a step of forming a film after application of the film-forming agent.

[0116] The film-forming agent is applied to the fibers before, simultaneously with, or after said binder composition (preferably, before or after said binder composition). In a particular embodiment, the binder composition and the film-forming agent are applied simultaneously. In such an embodiment, the binder composition and the film-forming agent may advantageously form a single composition comprising both:

[0117] - the raw materials necessary for the formation of an infusible binder,

[0118] - the film-forming agent, and

[0119] - any additives, fillers, and / or catalysts mentioned above.

[0120] When they form a single composition, the weight content of solid matter in said single composition is between 2 and 50%, preferably between 4 and 30%, or even between 4 and 20%, or even between 4 and 16% (i.e. relative to the total weight of the composition).

[0121] Preferably, the binder composition and the film-forming agent are applied to the fibers successively. More particularly, the film-forming agent is applied to the fibers after said binder composition and preferably before the step of heating the assembly of glued fibers. The application of the binder composition and the film-forming agent can be done by any means known to those skilled in the art. For example, the application can be done by spraying or by roller, preferably by spraying. The spraying is generally carried out by means of nozzles (spray rings). When the two compositions are applied one after the other, a double spray ring can in particular be used.

[0122] The formed bonded fiber assembly is heated to a temperature allowing the formation of an infusible binder (and typically the evaporation of water). When the film-forming agent is applied to the fibers before this heating step, the heating temperature is preferably such that it further allows the formation of a film of the film-forming agent. When the film-forming agent is applied to the fibers before the heating step, a sublimation step may be carried out after application of the film-forming agent to the fibers and before the heating step. This sublimation step is carried out under conditions allowing the formation of the film of the film-forming agent.

[0123] It is understood that said evaporation of water during the heating step refers to the elimination of water from the binder composition, as well as that of the film-forming agent when the latter comprises water (for example if it is applied to the fibers, in the form of an aqueous composition, before the heating step).

[0124] Preferably, the heating step is carried out at a temperature greater than or equal to 100°C, preferably greater than or equal to 120°C, or even greater than or equal to 140°C, and generally less than 250°C. In a particular embodiment, the film-forming agent is applied to the fibers after the step of heating the assembly of glued fibers. In such an embodiment, the method according to the invention advantageously comprises a step of film formation after application of the film-forming agent. This film formation can be carried out by sublimation or preferably by a second heating step at a temperature greater than the MFFT of the film-forming agent.

[0125] The method according to the invention makes it possible to form an acoustic insulation product comprising an assembly of fibers linked together by an infusible binder and by a film-forming agent.

[0126] Thus, an object of the present invention is an acoustic insulation product obtainable by the method according to the invention.

[0127] More particularly, the present invention relates to an acoustic insulating product comprising an assembly of fibers bound by an infusible binder and by a film-forming agent.

[0128] By "film-forming agent" is meant a film-forming agent as defined above, which has been subjected to a treatment allowing the formation of a film. Typically, the formation of the film occurs by heating the film-forming agent to a temperature above the MFFT (defined above). In the acoustic insulation product according to the invention, the film-forming agent is typically in the form of microfilms or micro-membranes between the fibers. The film-forming agent is not bound (in particular by covalent bonds) to the infusible binder and is therefore not part of it. The film-forming agent is distinct from the infusible binder.

[0129] It is understood that the various aspects, particular and preferred modes described above for the method of the invention also apply to the acoustic insulation product of the invention.

[0130] In particular, the materials constituting the film-forming agent are the same as those described for the film-forming agent. Thus, preferably, the film-forming agent is PVA.

[0131] In particular, in the acoustic insulation product according to the invention, the mass ratio of the quantity of infusible binder to the quantity of fibers is advantageously between 0.005 and 0.2, preferably between 0.01 and 0.15, or even between 0.01 and 0.1, or even between 0.02 and 0.07.

[0132] In particular, in the acoustic insulation product according to the invention, the mass ratio of the quantity of film-forming agent to the quantity of fibers is advantageously between 0.005 and 0.2, for example between 0.01 and 0.15, between 0.01 and 0.1, or between 0.02 and 0.07. Preferably, the mass ratio of the quantity of film-forming agent to the quantity of fibers is between 0.005 and 0.1, or even between 0.005 and 0.06, or even between 0.005 and 0.03.

[0133] The fibers generally represent at least 60%, advantageously at least 70%, preferably at least 80%, or even at least 90% of the total weight of the acoustic insulation product.

[0134] The density of the sound insulation product is advantageously at least 5 kg / m 3 , generally it ranges from 5 to 200 kg / m 3 , or from 10 to 150 kg / m 3 .

[0135] In some embodiments, the density of the acoustic insulation product ranges from 5 to 100 kg / m 3, for example from 5 to 50 kg / m 3 .

[0136] In some embodiments, the density of the acoustic insulation product is at least 30 kg / m 3 , generally at least 40 kg / m 3 , preferably at least 45 kg / m 3 , or at least 50 kg / m 3 . In some embodiments, the density of the acoustic insulation product ranges from 50 to 200 kg / m 3 , for example 100 to 200 kg / m 3 .

[0137] Density is defined and determined in accordance with European standard EN1602.

[0138] The sound insulation product advantageously has a Young's modulus that is at least 1.2 times higher, preferably at least 1.5 times higher, or even at least 2 times higher than the Young's modulus of a product not comprising a film-forming agent but which is otherwise essentially identical. When the fiber assembly of the sound insulation product is glass wool, the sound insulation product advantageously has a Young's modulus of at least 5 kPa, generally ranging from 5 to 5000 kPa (for example from 5 to 2000 kPa, from 5 to 1000 kPa, or from 10 to 500 kPa), or from 50 to 2000 kPa, measured for a micronaire of 15 L / min and a density of 40 kg / m2.

[0139] In some embodiments, the fiber assembly of the acoustic insulation product is glass wool and the Young's modulus of the acoustic insulation product is at least 10 kPa, generally at least 20 kPa, preferably at least 50 kPa, or even at least 100 kPa, or even at least 500 kPa, measured for a micronaire of 15 L / min and a density of 40 kg / m2.

[0140] In some embodiments, the fiber assembly of the acoustic insulation product is glass wool and the Young's modulus of the acoustic insulation product ranges from 200 to 5000 kPa, for example from 500 to 5000 kPa, or from 1000 to 5000 kPa, measured for a micronaire of 15 L / min and a density of 40 kg / m2.

[0141] Young's modulus is determined in accordance with ISO 18437-5.

[0142] In some embodiments, the acoustic insulation product has a damping factor (also referred to as "delta tangent") that is at least 1.2 times greater, preferably at least 1.5 times greater, or even at least 2 times greater than the damping factor of a product not comprising a film-formed agent but otherwise substantially the same.

[0143] When the fiber assembly of the acoustic insulation product is glass wool, the acoustic insulation product advantageously has a damping factor of between 0.02 and 0.2, for example between 0.04 and 0.15, or even between 0.05 and 0.1, or even between 0.07 and 0.09, measured for a micronaire of 15 L / min and a density of 40 kg / m2.

[0144] The damping factor is determined in accordance with ISO 18437-5.

[0145] In some embodiments, the acoustic insulation product has a specific air-flow resistivity (AFR) that is at least 1.2 times greater, preferably at least 1.5 times greater, or even at least 2 times greater than the AFR of a product not comprising a film-forming agent but which is otherwise essentially identical.

[0146] When the fiber assembly of the acoustic insulation product is glass wool, the acoustic insulation product advantageously has an AFR of at least 60 kN.s.rrr 4 , preferably at least 70 kN.s.rrr 4 , better still at least 80 kN.s.rrr 4 , or even at least 90 kN.s.rrr 4 , or even at least 100 kN.s.rrr 4 , for example at least 110 kN.s.rrr 4 , in particular at least 120 kN.s.rrr 4 , measured for a micronaire of 15 L / min and a density of 40 kg / m2.

[0147] AFR is determined in accordance with ISO 9053.

[0148] In some embodiments, the sound insulation product has a tortuosity that is at least 1.2 times greater, preferably at least 1.5 times greater, or even at least 2 times greater than the tortuosity of a product not comprising a film-forming agent but which is otherwise essentially identical. When the fiber assembly of the sound insulation product is a glass wool, the sound insulation product advantageously has a tortuosity of at least 1.2, preferably at least 1.3, more preferably at least 1.4, or even at least 1.5, or even at least 1.6, for example at least 1.8, in particular at least 2, measured for a micronaire of 15 L / min and a density of 40 kg / m2.

[0149] Tortuosity is determined in accordance with ASTM E2611-19.

[0150] The dimensions of the acoustic insulation product are not limiting. In certain embodiments, the acoustic insulation product has a thickness of 5 to 200 mm, preferably 10 to 100 mm, or even 10 to 50 mm.

[0151] In some embodiments, the acoustic insulation product has a thickness of 0.1 to 5 mm, for example 0.5 to 2 mm.

[0152] The thickness of the acoustic insulation product is determined in accordance with standard NF EN 823. In certain embodiments, the acoustic insulation product has a weight of at least 25 g / m 2 , preferably at least 100 g / m 2 .

[0153] The sound insulation product can be used in particular for the sound insulation of walls, partitions, metal cladding, sloping roofs, warm roofs, waterproof roofs, ceilings, floors and floors, or in air conditioning and air ducts.

[0154] It can also be used in vehicles, particularly as a replacement for polyurethane foams traditionally used in this field.

[0155] Depending on the application, sound insulation products can come in different forms. Typically, sound insulation products come in the form of panels, fleeces, tiles, or mattresses.

[0156] In this application, a range defined with the expression "between (X) and (Y)" includes the lower (X) and upper (Y) limits, and is equivalent to "from (X) to (Y)".

[0157] The following examples illustrate the present invention, in a non-limiting manner.

[0158] EXAMPLES

[0159] Example 1

[0160] The glass mats were prepared as follows: the glass fibers were impregnated in an aqueous solution containing the raw materials of the binder (hydrogenated sugar and citric acid), a catalyst, silane and the film-forming agent (PVA obtained by partial hydrolysis of polyvinyl acetate), in a 20*20 cm mold. The samples were cured with thickness adjustment by compression at 200 °C for 40 min in an oven.

[0161] The different masses and results are detailed in Table 1.

[0162] In samples 1 and 2, the PVA used has a weight average molar mass (Mw) of 145 to 186 kg / mol with 98% hydrolysis rate. In sample 3, the PVA used has a weight average molar mass (Mw) of 85 to 124 kg / mol with 98% hydrolysis rate. In sample 4, the PVA used has a weight average molar mass (Mw) of 146 to 166 kg / mol with 98% hydrolysis rate.

[0163] The hydrolysis rate of PVA is expressed relative to poly(vinyl acetate).

[0164] Density was determined in accordance with European standard EN1602. AFR was determined in accordance with ISO 9053, based on 5 samples of 40 mm diameter.

[0165] Tortuosity was determined in accordance with ASTM E2611-19. Young's modulus was determined in accordance with ISO 18437-5.

[0166] The damping factor was determined in accordance with ISO 18437-5.

[0167] Table 1

[0168] *Dry extract: 20% by weight; **PVA dry extract: 15% by weight; ***PVA dry extract: 1% by weight PAF=loss on ignition Example 2

[0169] A protocol similar to that of Example 1 was implemented, with a different binder (phenolic resin).

[0170] The different masses and results are detailed in Table 2.

[0171] In sample 5, the PVA used has a weight-average molar mass (Mw) of 3–98 kg / mol with 98% hydrolysis rate. Table 2

[0172] *Resin dry extract = 60%, **PVA dry extract = 5%

[0173] Example 3 A protocol similar to that of Example 1 was implemented, in order to prepare a low density glass mat (binder: hydrogenated sugar and citric acid).

[0174] The different masses and results are detailed in Table 3.

[0175] In sample 6, the PVA used has a weight average molar mass (Mw) of 145–186 kg / mol with 98% hydrolysis rate.

[0176] Table 3

[0177] *Solid extract: 20% by weight; **Solid extract: 1% by weight The results in Tables 1 to 3 show that the presence of a film-forming agent (here, PVA), in a low content (here, 2-5% by weight) makes it possible to improve the acoustic properties of the glass fiber mat. It should be noted in particular that the AFR is 1.8 to 2.1 times higher when 2-5% by weight of film-forming agent is present, in addition to the conventional binder (Table 1).

[0178] Interestingly, comparisons 1 and 2 show that the conventional binder, on its own, has very little impact on the acoustic properties of the resulting product. Indeed, the product obtained after a calcination step, which removes the binder, has an AFR and tortuosity close to those of the product before calcination. At lower density (Table 3), an improvement was also observed: in particular, sample 6 has an AFR 1.4 times higher than the corresponding calcined product (i.e. without binder and film-forming agent).

[0179] Tables 1 to 3 also show that mechanical properties are maintained or improved.

Claims

CLAIMS 1. Method for manufacturing a fiber-based acoustic insulation product comprising: - the supply of fibers; - the application to the fibers of a binder composition comprising raw materials necessary for the formation of an infusible binder, to form an assembly of glued fibers; and - heating the assembly of glued fibers, to a temperature allowing the evaporation of water and the formation of an infusible binder, in which a film-forming agent is applied to the fibers before, simultaneously with or after said binder composition.

2. The method of claim 1, wherein the film-forming agent is selected from polyvinyl alcohol, polyethylene, polyacrylate, polyacrylic acid, starch, cellulose and its derivatives, polyvinyl butyral, polyvinyl acetate, polyvinylpyrrolidone, chitosan, polypeptides, polysorbates, fatty acids, polyamino acids, glycol esters, glycerol esters, sorbitan esters, and a mixture of at least two of these.

3. A method according to claim 1 or 2, wherein the film-forming agent is polyvinyl alcohol.

4. Method according to any one of the preceding claims, in which the mass ratio of the quantity of film-forming agent to the quantity of fibers is between 0.005 and 0.2, preferably between 0.005 and 0.1, or even between 0.005 and 0.06, or even between 0.005 and 0.

03.

5. Method according to any one of the preceding claims, in which the mass ratio of the quantity of said raw materials necessary for the formation of an infusible binder to the quantity of fibers is between 0.005 and 0.2, preferably between 0.01 and 0.15, or even between 0.01 and 0.1, or even between 0.02 and 0.

07.

6. Method according to any one of the preceding claims, in which the mass ratio of the quantity of said raw materials necessary for the formation of an infusible binder to the quantity of film-forming agent is between 0.1 and 4, preferably between 0.1 and 3, or even 0.1 and 1.5, in particular between 0.1 and 1, for example between 0.4 and 1.

7. A method according to any one of the preceding claims, wherein the film-forming agent is applied to the fibers after said binder composition and preferably before the step of heating the assembly of sized fibers.

8. A method according to any one of the preceding claims, wherein said binder composition comprises a polyol and a polycarboxylic acid, an ester, anhydride, or salt thereof, or an oligoester thereof, the polyol preferably being a sugar, more preferably a reducing sugar, a non-reducing sugar, a hydrogenated sugar, or a mixture thereof.

9. Method according to any one of the preceding claims, in which the film-forming agent has a glass transition temperature of less than or equal to 140°C, preferably between -50°C and 140°C, preferably between -50°C and 45°C.

10. Method according to any one of the preceding claims, in which the fibers are mineral fibers optionally mixed with thermoplastic fibers.

11. Method according to any one of the preceding claims, in which the assembly of fibers is a mineral wool, in particular a glass wool or a rock wool.

12. A method according to any preceding claim, wherein said binder composition and film-forming agent, in the form of an aqueous composition, are applied by spraying.

13. Method according to any one of the preceding claims, in which the heating step is carried out at a temperature greater than or equal to 100°C, preferably greater than or equal to 120°C, or even greater than or equal to 140°C, and generally less than 250°C.

14. Method according to any one of the preceding claims, in which: - when the film-forming agent is applied to the fibres before said heating step, the heating temperature is such that it also allows the formation of a film of the film-forming agent, - when the film-forming agent is applied to the fibers after said step of heating the assembly of glued fibers, the method comprises a step of forming a film after application of the film-forming agent.

15. Acoustic insulating product comprising an assembly of fibers bound by an infusible binder and by a film-forming agent, in which the mass ratio of the quantity of film-forming agent to the quantity of fibers is advantageously between 0.005 and 0.

2.

16. Acoustic insulating product according to claim 15, in which the film-forming agent is polyvinyl alcohol. Tl

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