ADHESIVE COMPOSITION BASED ON FURAN RESIN, REDUCING SUGAR AND / OR NON-REDUCING SUGAR

Description

[0001] The present invention relates to the field of bonding for thermal and / or acoustic insulation products based on mineral wool, in particular glass or rock wool, and a formaldehyde-free organic binder.

[0002] The invention relates more particularly to a sizing composition capable of crosslinking to form said organic binder, which contains an aqueous solution of furan resin and reducing sugar and / or non-reducing sugar. It also relates to a process for manufacturing insulation products based on mineral or organic fibers bound by a binder using the aforementioned sizing composition, as well as the insulating products obtained by such a process.

[0003] The production of mineral wool insulation products generally includes a step of manufacturing the wool itself, which can be carried out using different processes, for example using the known technique of internal or external centrifugal fiberization.

[0004] Internal centrifugation, more commonly used to manufacture glass wool, consists of introducing the molten mineral material into a centrifugal device comprising a multitude of small orifices, the material being projected towards the peripheral wall of the device under the action of centrifugal force and escaping in the form of filaments. At the outlet of the centrifugal device, the filaments are stretched and carried towards a receiving organ by a gas current having a high temperature and speed, to form a sheet of fibers (or mineral wool).

[0005] External centrifugation consists of pouring the molten material onto the external peripheral surface of rotating members called rotors, from which the molten material is ejected under the action of centrifugal force. Means of gas flow drawing and collection on a receiving member are also provided.

[0006] To ensure the assembly of the fibers together and allow the sheet to have cohesion, a sizing composition 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 subjected to a heat treatment, at a temperature generally above 100°C, in order to carry out the crosslinking 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.

[0007] The sizing composition to be sprayed onto the mineral wool is generally in the form of an aqueous solution containing the thermosetting resin and additives such as a resin crosslinking catalyst, an adhesion-promoting silane, an anti-dust mineral oil, etc. The sizing composition is most often applied to the fibers by spraying.

[0008] The properties of the sizing composition depend largely on the characteristics of the resin. From an application point of view, it is necessary that the sizing composition has good sprayability and can be deposited on the surface of the fibers in order to effectively bond them.

[0009] The resin must be stable for a given period of time before being used to form the sizing composition, which composition is generally prepared at the time of use by mixing the resin and the additives mentioned above.

[0010] From a regulatory perspective, it is necessary that the resin is not harmful, that is to say that it contains - and generates during the gluing stage or subsequently - as few compounds as possible that could harm human health or the environment.

[0011] The most commonly used thermosetting resins for the manufacture of mineral wool insulation products are formaldehyde-based resins (urea-formaldehyde, phenol-formaldehyde, melamine-formaldehyde). These resins are inexpensive, water-soluble, and capable of crosslinking under the aforementioned thermal conditions. However, they may still contain a certain proportion of free formaldehyde, the harmful effects of which have been proven by toxicological studies. These resins are then treated with urea to fix this free formaldehyde in the form of non-volatile condensates. However, these condensates are unstable under the temperature conditions to which the glass fiber mats are subjected.They can decompose into formaldehyde and ammonia (itself a product of urea degradation) which are released into the processing atmosphere and must then be subject to capture procedures to reduce their impact on the environment. Solutions for replacing formaldehyde-based resins in sizing compositions have therefore been developed, as in application FR 3 019 815 A1, which describes sizing compositions based on non-reducing saccharides and hydrogenated saccharides.

[0012] "Furanic" or "polyfuranic" resins derived from plant-based biomass are one of the solutions used. These furanic resins, initially known in foundries to ensure the setting in the mold of molding sands, are conventionally used as binders for mineral fibers for the manufacture of mineral wool-based insulation products (see for example WO 93 / 25490, WO 94 / 26676, WO 94 / 26677, WO 94 / 26798). The furanic resins described in these documents are mixtures of monomers, oligomers and polymers obtained by polycondensation in an acid medium of monomers with a "furan" core and possibly other comonomers such as anhydrides, aldehydes, ketones, urea, phenol, etc.

[0013] Two furan resins are described in more detail in particular in WO 94 / 26677 as being commercial products, namely the products Farez™< M (QO Chemicals), a furfuryl alcohol and formaldehyde-urea resin containing 6% residual furfuryl alcohol and also 0.4 to 1.1% formaldehyde, and Quacorr™< 1300 (QO Chemicals), a resin obtained by polycondensation of furfuryl alcohol having a residual furfuryl alcohol content of between 2% and 18%.

[0014] Another commercially available furan resin is BioRez™ resin (TransFurans Chemicals, Belgium) obtained by polycondensation of furfuryl alcohol in the presence of an acid catalyst. It has an acid pH between approximately 4.5 and 5.5, a low furfuryl alcohol content (less than 1% of the commercial aqueous composition) and a viscosity at 25°C of less than 1000 mPa.s at 75% dry extract. This resin has a low residual furfuryl alcohol content, but an acid catalyst is still required to activate its polycondensation.

[0015] In application WO 2018 / 167429 A1, a concentrated solution of poly(furfuryl alcohol) for sizing organic or mineral fibers, stable during storage, is described.

[0016] However, all these furan resins are expensive, making the sizing compositions sprayed onto the fibers and containing these resins very expensive.

[0017] The Applicant therefore sought a bio-sourced, low-harm, inexpensive sizing composition, while retaining good mechanical properties and good crosslinking ability.

[0018] The idea behind the present invention is to replace a portion of the furan resins with a less expensive compound in known sizing compositions. It has been found that 5% to 60% by weight of at least one reducing sugar and / or at least one non-reducing sugar in a sizing composition comprising 40% to 95% by weight of furan resin, relative to the total dry weight of the composition, makes it possible to reduce the costs of said sizing composition while retaining good mechanical properties and good crosslinking ability.

[0019] Indeed, it was surprisingly found by the inventors that at least one sugar chosen from reducing sugars, non-reducing sugars, and mixtures thereof, and in the proportion indicated above, reacted with furan resin, unlike other compounds such as a hydrogenated sugar.

[0020] Furthermore, the Applicant has found that the presence of an acid and / or a base is not necessary in a sizing composition as defined above, to form the polymer network which constitutes the final binder. The sizing composition according to the present invention has the advantage of crosslinking, even in the absence of acid and / or base.

[0021] Thus, the present application more specifically relates to an aqueous sizing composition for mineral or organic fibers comprising: from 40% to 95% by weight of furan resin, and from 5% to 60% by weight of at least one reducing sugar and / or at least one non-reducing sugar, said sizing composition having a dry matter content of between 0.5% and 50% by weight.

[0022] Preferably, the sizing composition comprises from 10% to 50% by weight of at least one reducing sugar and / or at least one non-reducing sugar and preferably from 20% to 40% by weight, and more preferably from 20% to 30% relative to the total dry weight of the composition.

[0023] Preferably, the sizing composition comprises from 50% to 90% by weight of furan resin and preferably from 60% to 80% by weight, and more preferably from 70% to 80% relative to the total dry weight of the composition.

[0024] The furan resins according to the invention are well known as binders for glass fibers and are described in the aforementioned patent applications: WO 93 / 25490, WO 94 / 26676, WO 94 / 26677, WO 94 / 26798. According to a preferred embodiment of the invention, the furan resin is a furfuryl alcohol resin, called poly(furfuryl alcohol). Poly(furfuryl alcohol) denotes a self-condensation product of furfuryl alcohol in the form of oligomers comprising at least two furan units, where appropriate a mixture of oligomers of variable molecular weight. When the furan resin is a poly(furfuryl alcohol), the residual content of monomeric furfuryl alcohol in the sizing composition according to the invention is preferably as low as possible. Furfuryl alcohol (CAS number 98-00-0) is indeed a volatile organic compound (VOC) considered harmful by skin contact, inhalation and ingestion.The volatility, flammability and toxicity of furfuryl alcohol require precautions for use. Thus, the sizing composition of the present invention may contain less than 1.5% by weight, more preferably less than 1.0% by weight and ideally less than 0.1% by weight of furfuryl alcohol.

[0025] The reducing sugar of the sizing composition according to the present invention is a monosaccharide, an oligosaccharide, a polysaccharide or a mixture of these compounds.

[0026] Examples of monosaccharides include glucose, galactose, mannose, and fructose.

[0027] By "oligosaccharide" is meant a saccharide containing 2 to 10 monosaccharide units, preferably at most 5.

[0028] Examples of oligosaccharides include lactose, maltose, isomaltose, and cellobiose.

[0029] The polysaccharides in accordance with the invention are chosen from polysaccharides having a number-average molar mass of less than 100,000, preferably less than 50,000 and advantageously less than 10,000.

[0030] As an example of a preferred polysaccharide, mention may be made of dextrins. Dextrins are compounds corresponding to the general formula (C 6 H 10 O 5 ) n obtained by partial hydrolysis of starch. The methods for preparing dextrins are known. For example, dextrins can be prepared by heating or dry drying a starch, generally in the presence of an acid catalyst, which leads to the breakdown of the amylose and amylopectin molecules that constitute said starch into products of lower molar mass. Dextrins can also be obtained by treating the starch enzymatically with one or more amylases, in particular microbial amylases, capable of hydrolyzing the bonds in the starch. The nature of the treatment (chemical or enzymatic) and the hydrolysis conditions have a direct impact on the average molar mass and the molar mass distribution of the dextrin.

[0031] The dextrins according to the present invention have a dextrose equivalent DE (Dextrose Equivalent in English) greater than 5, preferably greater than 30, and more preferably greater than 50.

[0032] Conventionally, the dextrose equivalent DE is defined by the following relationship: DE = 100 × nombre de liaisons glycosidiques rompues nombre de liaisons glycosidiques dans l ′ amidon initial

[0033] The dextrins in accordance with the invention may be obtained from starch or starch derivatives of various plant origin, for example from tubers such as potato, cassava, maranta and sweet potato, from seeds such as wheat, corn, rye, rice, barley, millet, oats and sorghum, from fruits such as chestnut, sweet chestnut and hazelnut, or from legumes such as pea and bean.

[0034] Preferably, the reducing sugar is chosen from glucose, polysaccharides composed mainly (i.e. more than 50% by weight) of glucose units and mixtures of these compounds.

[0035] Preferably, the reducing sugar is glucose or maltose, and advantageously glucose.

[0036] The non-reducing sugar according to the present invention designates a saccharide consisting of several saccharide units of which carbon 1 bearing the hemiacetal OH group is engaged in a bond. A non-reducing sugar within the meaning of the invention has no reducing action on copper-alkaline solutions.

[0037] The non-reducing sugar of the sizing composition according to the present invention is a non-reducing oligosaccharide containing at most 10 saccharide units.

[0038] Examples of such non-reducing sugars include disaccharides such as trehalose, isotrehaloses, sucrose, and isosucroses; trisaccharides such as melezitose, gentianose, raffinose, erlose, and umbelliferose; tetrasaccharides such as stachyose; and pentasaccharides such as verbascose.

[0039] Sucrose and trehalose are preferred, and sucrose is even better.

[0040] In a preferred embodiment, the sizing composition is free of hydrogenated sugars. By "hydrogenated sugar" is meant all the products resulting from the reduction, in any manner whatsoever, of a sugar chosen from monosaccharides, oligosaccharides, linear, branched or cyclic polysaccharides, and mixtures of these products.

[0041] In a preferred embodiment, the sizing composition is formaldehyde-free, thus providing an alternative to resol-based sizing compositions, as explained above. In the present application, the term "formaldehyde-free" means a quantity of formaldehyde of less than 2000 ppm in a sizing composition according to the invention.

[0042] The sizing composition is an aqueous composition which has a dry matter content of between 0.5% and 50% by weight, preferably between 2% and 30% by weight, and more preferably between 4% and 25% by weight; the furan resin and the reducing sugar and / or the non-reducing sugar together advantageously representing at least 50% by weight, preferably at least 75% by weight of the dry matter of the sizing composition.

[0043] The sizing composition according to the invention may further comprise the following additives in the following proportions calculated on the basis of 100 parts by weight of reducing sugar and / or non-reducing sugar and furan resin: 0 to 5 parts of silane, in particular aminosilane or epoxysilane, 0 to 25 parts of oil, preferably 4 to 20 parts 0 to 10 parts of a hydrophobic agent, in particular a silicone, and 0 to 30 parts of urea, preferably 0 to 20 parts.

[0044] These additives are normally added when diluting the composition, but in principle there is nothing to prevent them from being added to the concentrated composition, which then simply needs to be diluted with water.

[0045] The role of additives is known and briefly recalled: silane is a coupling agent between the fibers and the binder, and also plays the role of anti-aging agent; oils and in particular mineral oils are anti-dust agents, silicones are hydrophobic agents; urea plays the role of plasticizer and prevents pre-gelling of the sizing composition.

[0046] From 0 to 20 parts of polyol may also be added to the sizing composition as an additive, said polyol may in this case be chosen from glycerol, a glycol such as ethylene glycol, propylene glycol, butylene glycol and poly(alkylene) glycols based on these glycols, or homopolymers and copolymers of vinyl alcohol. Said polyols may also act as a plasticizer and make it possible to avoid pre-gelling of the sizing composition.

[0047] The additives advantageously represent at least 5% by weight, preferably at least 10% by weight of the dry matter of the sizing composition.

[0048] The pH of the aqueous sizing composition according to the invention may be between 3.0 and 10.0, preferably between 4.0 and 9.0, in particular between 4.5 and 8.5 and ideally between 5.0 and 7.0.

[0049] The pH of the aqueous sizing composition can be adjusted by simply adding an organic base, for example by adding an aqueous ammonia solution (NH 4 OH) or an amine, for example a primary or secondary amine. Preferably, ammonia and / or primary or secondary amines are used. In an advantageous embodiment, the amine is a polyamine preferably comprising 2 to 5 primary / secondary amine functions, or an amine polymer such as polyethyleneimine.

[0050] The Applicant was surprised to find that the addition of such a base to the sizing composition had no influence on the crosslinking speed of the furan resin with the reducing sugar and / or the non-reducing sugar and did not modify the mechanical properties of said composition. However, an increase in pH makes it possible to slow down or even stop the increase in viscosity and to transport the resin (formed of furan resin and at least one reducing sugar and / or one non-reducing sugar) in concentrated form at room temperature and then to store it for several weeks in a non-refrigerated environment.

[0051] The viscosity of the solution can vary within wide limits. The Brookfield viscosity of solutions of furan resin and reducing sugar and / or non-reducing sugar is measured at 25°C using a Brookfield viscometer (according to the method described in ASTM D2983), after adjustment of the dry matter content, by removal or addition of water, up to 50% by weight, preferably up to 30% by weight. Under these conditions it is preferably between 1 and 1000 mPa.s, more preferably between 2 and 500 mPa.s, in particular between 3 and 100 mPa.s.

[0052] The dilutability, or "dilutability," of a concentrated resin solution is defined as the volume of deionized water that can be added to a unit volume of the aqueous resin solution at a given temperature before permanent cloudiness occurs. A resin is generally considered suitable for use as a size when its dilutability is 1000% or greater at 20°C.

[0053] The aqueous solution of furan resin and reducing sugar and / or non-reducing sugar advantageously has a dilutability greater than 1000%, preferably greater than 2000%.

[0054] In a preferred embodiment, and as explained above, the sizing composition is free of base and / or acid such as an organic polycarboxylic acid, or a metal salt of an inorganic acid, or an ammonium salt of an inorganic acid, or a hypophosphorous acid, or phosphoric acid. Indeed, it has been surprisingly found by the inventors that a reducing sugar and / or a non-reducing sugar does not need acid to react with the furan resin in the sizing composition according to the invention.

[0055] The invention also relates to a method for manufacturing an insulation product based on mineral or organic fibers bound by an organic binder, comprising the following steps: (a) applying a sizing composition as described above to mineral or organic fibers, (b) forming an assembly of mineral or organic fibers, (c) heating the assembly of mineral or organic fibers until said sizing composition hardens.

[0056] In a preferred embodiment of the method of the invention, step (a) of applying the sizing solution to the mineral or organic fibers may be carried out by spraying using spray nozzles. The application of the sizing composition preferably precedes step (b) of assembly, during which the sized fibers are gathered, for example in a mold or on a conveyor before being heated consecutively or extemporaneously to crosslink and harden the binder.

[0057] The sizing composition according to the invention can be used to bind mineral or organic fibers, preferably mineral fibers, and even more preferably mineral wool.

[0058] Organic fibers can be natural, artificial (i.e., natural fibers that have undergone chemical modification), or synthetic fibers.

[0059] The mineral fibers are in particular glass fibers, in particular E, C, R or AR (alkali-resistant) glass, or rock fibers, in particular basalt (or wollastonite). These fibers may be fibers containing more than 96% by weight of silica and ceramic fibers based on at least one oxide, nitride or carbide of metal or metalloid, or a mixture of these compounds, in particular at least one oxide, nitride or carbide of aluminum, zirconium, titanium, boron or yttrium. And more particularly, the mineral fibers according to the invention are aluminosilicate glass fibers, in particular aluminosilicate glass fibers comprising aluminum oxide, Al 2 O 3 , in a mass fraction of between 14% and 28%.

[0060] The fibers can be assembled, in flexible mattresses, for example in mineral wool mattresses such as glass wool or rock wool mattresses, rollable and compressible or foldable, in fiber plates or panels, denser and more rigid than rollable mattresses, in molded fiber-based products, for example linings for conduits or pipes, in woven or non-woven textiles, such as non-woven mats of glass or organic fibers.

[0061] Step (c) of heating the fiber assembly is preferably carried out at a temperature of between 100°C and 250°C for a period of between 1 minute and 10 minutes, preferably in a thermo-regulated enclosure, such as a forced-air oven into which hot gases of controlled temperature are introduced into one or more compartments, a microwave oven, or a heating mold with fluid circulation or heating resistance.

[0062] In a preferred embodiment of the method according to the invention, the fibers are mineral fibers and the assembly of mineral fibers exhibits, after the hardening step (c), a loss by combustion (LOI, from the English loss on ignition ) between 1% and 20%, preferably between 1% and 7% by weight.

[0063] The invention also relates to an insulating product, in particular an acoustic and / or thermal insulation product based on mineral or organic fibers bound by an organic binder, obtained by a method as described above. The insulating product obtained then comprises mineral or organic fibers and a binder obtained by curing a sizing composition comprising an aqueous solution of furan resin and reducing sugar and / or non-reducing sugar (as described above). The insulating product according to the invention has a tensile strength and a thickness recovery after compression equivalent to those of an insulating product obtained according to the prior art, that is to say equivalent to an insulating product comprising mineral or organic fibers and a binder obtained by curing a sizing composition comprising a furan resin alone (without sugar(s)).

[0064] Preferably, the mineral or organic fiber-based products according to the invention are mineral wool-based products which can also be used in soilless cultivation. Examples Example 1 :

[0065] Aqueous sizing compositions are prepared comprising as furan resin a furfuryl alcohol resin, called poly(furfuryl alcohol) (BioRez ™< (TransFurans Chemicals, Belgium)) with glucose (D-(+)-Glucose ≥ 99.5% from Sigma Aldrich). The aqueous sizing compositions below have a dry matter content of 20% by weight. The amount, i.e. the weight percentage of the poly(furfuryl alcohol) and that of the glucose, relative to the total dry weight of the composition, is varied with a step of 10% as indicated in Table 1. [Table 1] Sample Name Percentage of poly(furfuryl alcohol) Glucose percentage PFA_G_1 100 0 PFA_G_2 90 10 PFA_G_3 80 20 PFA_G_4 70 30 PFA_G_5 60 40 PFA_G_6 50 50 PFA_G_7 40 60 PFA_G_8 30 70 PFA_G_9 20 80 PFA_G_10 10 90 PFA_G_11 0 100

[0066] Two series of glass cloths are impregnated with these aqueous sizing compositions, then the cloths are passed over a suction device to remove the excess solution. The impregnated glass cloths are then cured in a thermostatically controlled oven at 220°C. After 90 seconds and 120 seconds of curing, a sample is subjected to a determination of the tensile strength. For this purpose, the cloths are cut into strips (300 mm x 50 mm) and their ends are inserted into the jaws of a tensile testing machine. The tensile testing machine used is an MTS, the load cell is 2 kN and the jaws use pneumatic clamping.

[0067] Table 2 shows the maximum tensile strength achieved for two curing times (90 seconds and 120 seconds) at a temperature of 220°C of glass fiber fabrics impregnated with a sizing composition according to Table 1. [Table 2] Sample Name Cooking time Maximum tensile force (N) PFA_G_1 90 s 96, 7 PFA_G_1 120 s 92,9 PFA_G_2 90 s 98,3 PFA_G_2 120 s 92,7 PFA_G_3 90 s 92,8 PFA_G_3 120 s 93,4 PFA_G_4 90 s 91,8 PFA_G_4 120 s 89,0 PFA_G_5 90 s 83,6 PFA_G_5 120 s 85,8 PFA_G_6 90 s 76,6 PFA_G_6 120 s 82,5 PFA_G_7 90 s 75,8 PFA_G_7 120 s 72,0 PFA_G_8 90 s 66,6 PFA_G_8 120 s 62,3 PFA_G_9 90 s 48,2 PFA_G_9 120 s 54,6 PFA_G_10 90 s Too weak to be measured PFA_G_10 120 s 26,8 PFA_G_11 90 s Too weak to be measured PFA_G_11 120 s Too weak to be measured

[0068] It can be seen that the samples prepared according to the invention (PFA_G_2 to PFA_G_7) comprising from 10% to 60% by weight of glucose have satisfactory tensile strengths compared to that of the reference sample which comprises 100% by weight of poly(furfuryl alcohol). On the other hand, the mechanical tensile properties of the samples (PFA_G_8 to PFA_G_11) comprising from 70% to 100% by weight of glucose decrease and even become very low since measurements cannot be carried out on the samples comprising respectively 90% and 100% of glucose (PFA_G_10 and PFA_G_11). Example 2 :

[0069] Aqueous sizing compositions are prepared comprising 60% by weight of poly(furfuryl alcohol) as furan resin ((BioRez ™< (TransFurans Chemicals, Belgium)) and 40% by weight of different sugars, relative to the total dry weight of the composition: reducing sugars such as fructose (D-(-)-fructose from Sigma Aldrich) and maltodextrin ((DE 16.5-19.5) Maldex ®< Tereos Syral), non-reducing sugar such as sucrose (D(+)-Sucrose from Sigma Aldrich) and hydrogenated sugar such as sorbitol (D-sorbitol from Sigma Aldrich). The aqueous sizing compositions below have a dry matter content of 20% by weight. The description of the solutions is presented in Table 3. [Table 3] Sample Name Sugar used Percentage of poly(furfuryl alcohol) Percentage of sugar used PFA_S_1 fructose 60 40 PFA_S_2 maltodextrin (DE 16.5-19.5) 60 40 PFA_S_3 sucrose 60 40 PFA_S_4 sorbitol 60 40

[0070] Table 4 below shows the maximum tensile strength achieved (measured according to the method described in Example 1) for two curing times at a temperature of 220°C of impregnated glass fiber fabrics (such as those described in Example 1) with a sizing composition according to Table 3. [Table 4] Cooking time Maximum tensile force (N) PFA_S_1 90 s 87,7 PFA_S_1 120 s 85,2 PFA_S_2 90 s 108,4 PFA_S_2 120 s 111,7 PFA_S_3 90 s 91,8 PFA_S_3 120 s 92,5 PFA_S_4 120 s 50,1 PFA_S_4 300 s 67,1

[0071] It is found that the samples prepared according to the invention with fructose, maltodextrin and sucrose have satisfactory tensile strengths. On the other hand, the use of sorbitol significantly reduces the tensile mechanical properties of the sizing composition, even with a longer cooking time (300 seconds). Example 3 :

[0072] Aqueous sizing compositions are prepared comprising the constituents listed in Table 5 expressed in parts by weight (as a percentage by weight relative to the total dry weight of the composition). [Table 5] Sample Name Reducing sugar used Percentage of: poly(furfuryl alcohol) (1)< (furan resin) Percentage of sugar used PFA_P_1 - 100 0 PFA_P_2 glucose (2)< 80 20 PFA_P_3 glucose (2)< 60 40 (1)< BioRez ™< (TransFurans Chemicals, Belgium) (2)< D-glucose hydrate

[0073] The sizing compositions are prepared by introducing the constituents into a container containing water, under vigorous stirring. The sizing compositions below have a dry matter content of 5% by weight.

[0074] Bonding compositions are used to form glass wool insulation products.

[0075] Glass wool is manufactured by the internal centrifugation technique in which the molten glass composition is transformed into fibers by means of a tool called a centrifugation plate, comprising a basket forming the receiving chamber for the molten composition and a peripheral strip pierced with a multitude of orifices: the plate is rotated around its vertically arranged axis of symmetry, the composition is ejected through the orifices under the effect of centrifugal force and the material escaping from the orifices is drawn into fibers with the assistance of a current of drawing gas. The fineness of the glass fibers, measured by their micronaire value under the conditions described in patent application FR 2 840071, is equal to 15.8 l / min. There is a correspondence relationship between the micronaire value and the average diameter of the fibers.

[0076] Conventionally, a sizing spray crown is placed below the fiberizing plate so as to evenly distribute the sizing composition over the newly formed glass wool.

[0077] The mineral wool thus bonded is collected on a 2.40 m wide belt conveyor, equipped with internal suction boxes which retain the mineral wool in the form of a felt or a sheet on the surface of the conveyor. The conveyor then circulates in an oven maintained at 240°C where the bonding constituents polymerize to form a binder. The resulting insulation product has a density equal to 17.5 kg / m 3< , a thickness of approximately 80 mm immediately after manufacture and a loss on ignition equal to 4.7%.

[0078] In this example, the tensile strength is measured, according to ASTM C 686-71T, on a specimen stamped from the insulation product. The specimen has the shape of a torus, 122 mm long, 46 mm wide, with a radius of curvature of the outer edge cut equal to 38 mm and a radius of curvature of the inner edge cut equal to 12.5 mm.

[0079] The sample is placed between two cylindrical mandrels of a testing machine, one of which is mobile and moves at a constant speed. The breaking force F of the sample is measured and the tensile strength RT is calculated, defined by the ratio of the breaking force F (in Newtons) to the mass of the sample (in Newtons / gram). The tensile strength is measured immediately after manufacture (initial tensile strength).

[0080] The "thickness recovery" indicates the compression elasticity of the final product. To measure it, a compression pressure is applied for a given time such that the thickness is reduced to 1 / 4.8 of its initial value. After releasing this compression pressure, the thickness is measured again. The thickness recovery is the ratio of the thickness measured after releasing the compression pressure to the initial thickness.

[0081] The properties of insulation products are given in the table [Table 6] Sample Name Tensile strength (N / g) Thickness recovery (cm) PFA_P_1 4,09 107,95 PFA_P_2 4,36 108,55 PFA_P_3 3,53 110,31

[0082] It can be seen that the insulating products prepared in accordance with the invention (PFA_P_2 and PFA_P_3) have a tensile strength and thickness recovery equivalent to those of the reference sample (PFA_P_1). Example 4

[0083] The procedure is as described in Example 3, but using dextrose as the reducing sugar. Tables 7 and 8 specify the weight fractions of the sizing compositions used and the mechanical properties of the mineral wool samples obtained. [Table 7] Sample Name Reducing sugar used Percentage of: poly(furfuryl alcohol) (1)< (furan resin) Percentage of sugar used PFA_P_4 - 100 0 PFA_P_5 dextrose (2)< 60 40 (1)< BioRez ™< (TransFurans Chemicals, Belgium) (2)< dextrose monohydrate from Roquette [Table 8] Sample Name Tensile strength (N / g) Thickness recovery (cm) PFA_P_4 4,45 105,66 PFA_P_5 4,06 108,11

[0084] It can be seen that the insulating product prepared in accordance with the invention (PFA_P_5) has a tensile strength and thickness recovery equivalent to that of the reference sample (PFA_P_4).

Claims

1. Aqueous binding composition for mineral or organic fibres comprising: - from 40 to 95 wt% of furan resin, and - from 5 to 60 wt% of at least one reducing sugar and / or of at least one non-reducing sugar, relative to the total dry weight of the composition, said binding composition having a dry matter content between 0.5 to 50 wt%.

2. Binding composition according to Claim 1, characterized in that the furan resin is a furfuryl alcohol resin, called poly(furfuryl alcohol).

3. Binding composition according to Claim 1 or 2, characterized in that it comprises from 10 to 50 wt% of at least one reducing sugar and / or of at least one non-reducing sugar and preferably from 20 to 40 wt%, and more preferably from 20 to 30 wt% relative to the total dry weight of the composition.

4. Binding composition according to any one of the preceding Claims 1 to 3, characterized in that the reducing sugar is glucose, galactose, mannose, fructose, lactose, maltose, isomaltose, cellobiose or a dextrin, preferably glucose and maltose, and advantageously glucose.

5. Binding composition according to Claim 4, characterized in that the dextrin has a dextrose equivalent (DE) above 5, preferably above 30, and more preferably above 50.

6. Binding composition according to any one of the preceding Claims 1 to 3, characterized in that the non-reducing sugar is trehalose, an isotrehalose, sucrose, an isosucrose, melezitose, gentianose, raffinose, erlose, umbelliferose, stachyose or verbascose, preferably sucrose and trehalose, and advantageously sucrose.

7. Binding composition according to any one of the preceding claims, characterized in that it is free from hydrogenated sugars.

8. Binding composition according to claim 1, characterized in that it has a dry matter content between 2 and 30 wt%, preferably between 4 and 25 wt%; the furan resin and the reducing sugar and / or non-reducing sugar together advantageously representing at least 50 wt%, preferably at least 75 wt% of the dry matter of the binding composition.

9. Binding composition according to any one of the preceding claims, characterized in that it has a pH between 3.0 and 10.0, preferably between 4.0 and 9.0, in particular between 4.5 and 8.5 and ideally between 5.0 and 7.0.

10. Binding composition according to any one of the preceding claims, characterized in that it further comprises the additives given hereunder in the following proportions calculated on the basis of 100 parts by weight of reducing sugar and / or of non-reducing sugar and of furan resin: - 0 to 5 parts of silane, in particular aminosilane or an epoxysilane, - 0 to 25 parts of oil, preferably 4 to 20 parts, - 0 to 10 parts of a hydrophobic agent, in particular a silicone, and - 0 to 30 parts of urea, preferably from 0 to 20 parts.

11. Method for making an insulation product based on mineral or organic fibres bound with an organic binder, comprising the following steps: (a) applying a binding composition according to any one of the preceding claims on mineral or organic fibres, (b) forming an assembly of mineral or organic fibres, (c) heating the assembly of mineral or organic fibres until said binding composition hardens.

12. Method according to the preceding claim, such that said binding composition in step a) is applied on the mineral or organic fibres by spraying by means of spraying nozzles.

13. Method according to either one of Claims 11 or 12, characterized in that the assembly of mineral or organic fibres is a blanket of fibres, a board or a panel of fibres, a fibre-based moulded product, or a woven or non-woven textile.

14. Method according to any one of Claims 11 to 13, characterized in that step (c) comprises heating said assembly of fibres at a temperature between 100°C and 250°C for a time between 1 and 10 minutes, preferably in a temperature-controlled enclosure.

15. Method according to any one of claims 11 to 14, characterized in that the fibres are mineral fibres and the assembly of mineral fibres has, after the curing step (c), a loss on ignition (LOI) between 1 and 20 wt%, preferably between 1 and 7 wt%.

16. Insulating product based on mineral or organic fibres bound with an organic binder, obtained by a method according to any one of Claims 11 to 15.