Resin and sizing composition comprising same

Abstract

The invention relates to a resin based on hemicellulose-lignin complexes, intended to form part of a sizing composition for mineral fibres. This resin is obtained by condensation of a hemicellulose-lignin complex with formaldehyde and optionally an amine compound and / or phenol. The invention also relates to the sizing composition for mineral fibres containing same and to the insulating products resulting therefrom.

Description

[0001] Resin and gluing composition comprising it

[0002] TECHNICAL FIELD

[0003] The invention relates to a resin based on hemicellulose-lignin complexes, intended for use in the formulation of a sizing composition for mineral fibers. This resin is obtained by the condensation of a hemicellulose-lignin complex with formaldehyde and optionally an amine compound and / or phenol. The invention also relates to the mineral fiber sizing composition containing the resin and to the resulting insulating products.

[0004] BACKGROUND OF THE INVENTION

[0005] Mineral fiber insulation products typically consist of a web or mat of rock or glass fibers bonded together with a sizing compound containing a thermosetting resin. The web or mat of fibers coated with the sizing compound is then subjected to heat treatment (generally at a temperature above 100°C) to induce polycondensation of the resin and obtain a thermal and / or acoustic insulation product with specific properties.

[0006] The sizing composition consists of resin and standard additives, carried in water to allow for easy application to the fibers, most often by spraying. From a regulatory standpoint, the resin must be considered non-polluting, meaning that it must contain—and generate during the sizing process or subsequently—as few compounds as possible that are considered harmful to human health or the environment.

[0007] The most commonly used thermosetting resins are phenolic resins belonging to the resol family. Besides their good crosslinking ability in alkaline environments under the aforementioned thermal conditions, these resins are highly soluble in water, have a good affinity for mineral fibers, particularly glass, and are relatively inexpensive. These resins are generally obtained by the condensation of phenol and formaldehyde in the presence of a basic catalyst, at a formaldehyde / phenol molar ratio typically greater than 1, in order to promote the reaction between phenol and formaldehyde and to reduce the residual phenol content in the resin. However, the residual formaldehyde and phenol content in the resin remains high.

[0008] To reduce the amount of residual formaldehyde, the Applicant proposed improved resol resins, the preparation process of which includes an additional reaction step consisting of reacting resols composed essentially of phenol / formaldehyde condensates, phenol, and formaldehyde with an amine compound, namely an alkanolamine such as monoethanolamine (W02008 / 043960, W02008 / 043961) or, alternatively, glycine (EP 2 609 129). These amine compounds react via the Mannich reaction with the phenol / formaldehyde (PF) condensates and with residual phenol and formaldehyde to form phenol / formaldehyde / amine (PFA) condensates.

[0009] Although these resins meet current regulatory requirements for formaldehyde emissions and phenol content, further progress still needs to be made to reduce the environmental impact of the production of insulating products, particularly glass wool.

[0010] One approach explored to achieve this goal is to substitute a portion of the phenol with lignin in resol resins. Lignin, a by-product of the paper industry rich in phenolic polymers, has a low carbon footprint and is readily available at a moderate cost. However, incorporating lignin into a resol resin generally requires prior activation (W02023 / 055303), which complicates the resin preparation process. Furthermore, it has been observed that substituting a significant fraction of the phenol with lignin in the previously described amino resols results in reduced resin dilubility.

[0011] Nevertheless, the need remains for a resol-type resin with a lower environmental impact than current resol resins, without negatively affecting the resin's production costs or properties, particularly its dilubility (or water tolerance) and the tensile strength of the insulating product. In this context, the inventors have developed a resin meeting the aforementioned needs, the synthesis of which involves a hemicellulose-lignin complex. Such a complex has already been described as usable in the manufacture of packaging films (US-9,243,078). However, to the Applicant's knowledge, its use as a substitute for all or part of the phenol in the manufacture of resol resins has never been suggested.

[0012] SUMMARY OF THE INVENTION

[0013] The present invention thus relates to a resin obtained from a reaction mixture comprising:

[0014] (a) a lignin-hemicellulose complex, in particular derived from wood,

[0015] (b) formaldehyde,

[0016] (c) possibly, phenol,

[0017] (d) optionally, an amino compound selected from an alkanolamine and glycine.

[0018] Another object of the invention is a process for preparing this resin, comprising the successive steps of:

[0019] - a first condensation of the lignin-hemicellulose complex, and possibly phenol, with formaldehyde, in the presence of a basic catalyst, at a temperature of 50 to 100°C,

[0020] - a second condensation with an amine compound chosen from an alkanolamine and glycine, according to the Mannich reaction, at a temperature of 50 to 75°C, preferably 55 to 65°C,

[0021] - the cooling of the reaction medium, and

[0022] - possibly, the addition of urea.

[0023] The invention also relates to an aqueous sizing composition for mineral fibers comprising said resin and optionally sizing additives.

[0024] Its purpose is also the use of this gluing composition to glue mineral fibers, preferably glass wool or rock wool fibers, in order to form thermal and / or acoustic insulation products.

[0025] The invention also relates to an insulation product, in particular thermal and / or acoustic, comprising mineral fibers, preferably glass wool or rock wool fibers, and a binder that can be obtained by baking this gluing composition.

[0026] The resin according to the invention has a lower environmental impact than prior art phenolic resins. Furthermore, it has been observed to possess high and stable dilutability over time, even at high phenol substitution rates. In addition, the resulting insulation products exhibit mechanical properties comparable to those of products obtained using known resol resins.

[0027] DETAILED DESCRIPTION

[0028] In the remainder of this description, the expression "between" is understood as referring to a range of values ​​including the limits mentioned.

[0029] The invention relates to a resol-type resin obtained from a reaction mixture comprising a lignin-hemicellulose complex (LCC). In this description, "lignin-hemicellulose complex" or "LCC" refers to a mixture of polymers, in particular block copolymers, each containing lignin and hemicellulose linked by covalent bonds. Specifically, the lignin and hemicellulose in the lignin-hemicellulose complex may be linked by at least one benzyl ether, benzyl ester, phenyl glycosidic, ferulate ester, and / or diferulate ester bond. "Hemicellulose" refers to at least one polysaccharide selected from: lexylane, xyloglucan, mannan, arabinoglucuronoxylan, glucuronoxylan, glucomannan, galactoglucomannan, and mixtures thereof.The term "lignin" refers both to lignin itself and to sulfonated lignin obtained, in particular, from a wood delignification process, especially in the manufacture of paper pulp using a sulfate (alkaline), such as the kraft process, or a bisulfite (neutral or acidic). Although lignin is naturally bound to hemicellulose in nature and after the aforementioned treatments, it differs from the hemicellulose-lignin complex used according to the invention by several characteristics, in particular its molar mass and the amount of neutral monosaccharides and Klason lignin it contains. "Klason lignin" refers to the amount of lignin insoluble in sulfuric acid, determined according to TAPPI T222-om 02 or ASTM D1106. This includes the residue obtained after removing carbohydrates by treating wood powder with 72% sulfuric acid at 30°C for 4 hours, then with 3% acid under reflux for 2 hours.

[0030] The hemicellulose-lignin complex used according to the invention thus generally has a weight average molecular mass (Mw) greater than 20,000 Da, preferably greater than 25,000 Da or even greater than 30,000 Da and up to 250,000 Da, as measured at 25°C by size exclusion chromatography (SEC) on three 300 x 8 mm columns in series containing porous particles (particle size: 10 pm, pore size: 300, 1000 and 1000 Angstrom) of modified acrylic copolymer (PSS SUPREMA, Agilent Technologies France), after dissolution in 10 mM of a 2 mg / mL NaOH solution, the eluent being the same solution injected at a rate of 1 mL / min, using pullulan standards.

[0031] Furthermore, in one embodiment of the invention, the hemicellulose-lignin complex contains:

[0032] an amount of neutral monosaccharides, determined by chromatography after acid hydrolysis, which is greater than 5% by weight, preferably greater than 10% by weight, or even greater than 15% by weight, relative to the dry weight of the hemicellulose-lignin complex, and / or

[0033] - an amount of Klason lignin, determined after acid hydrolysis, which is less than 60% by weight, preferably less than 50% by weight and more preferably less than 40% by weight, relative to the dry weight of the hemicellulose-lignin complex, and / or

[0034] - a lignin / neutral monosaccharide weight ratio, determined by chromatography after acid hydrolysis, between 1.5 and 5, and / or - a quantity of phenolic groups carried by an aromatic ring, as determined by 31P NMR, which is less than 4 mmol / g, preferably less than 3 mmol / g, or even less than 2 mmol / g, or even less than 1 mmol / g, relative to the dry weight of the hemicellulose-lignin complex, and / or

[0035] - a quantity of mannose, determined by chromatography after acid hydrolysis, which is greater than 10% by weight, preferably greater than 20% by weight, more preferably greater than 30% by weight, or even greater than 40% by weight, relative to the total dry weight of neutral monosaccharides in the hemicellulose-lignin complex.

[0036] The acid hydrolysis implemented in the above methods is generally carried out using sulfuric acid, for example according to SCAN-CM 71:09 2009. The chromatographic methods used to measure the quantity of the above constituents may be chosen, in particular, from a high-performance anion-exchange chromatography method with a pulsed amperometric detector (HPAE-PAD) or a gas chromatography method as described in TAPPI T249-cm 00. Analytical methods usable for characterizing the hemicellulose-lignin complex according to the invention are described, in particular, in A. Abadessa et al., BioRessources (2018) 13(4), 7606-7627, in B. Asikanius et al., Carbohydrate Polymer Technologies and Applications (2024) 8, 100591 and in US patent 9,243,078.The hemicellulose-lignin complex used according to the invention preferably has the characteristics described above as measured according to at least one of these methods.

[0037] Such a hemicellulose-lignin complex is notably available commercially from the company ECOHELIX under the trade name Woodmer® Pulp or from the company KEMIRA under the reference FennoSize® EE 450.

[0038] Alternatively, the hemicellulose-lignin complex used according to the invention can be prepared by various processes from effluents of the paper industry, in particular from by-products of pulp manufacturing. These by-products can thus be derived from different wood sources, preferably from hardwoods (including eucalyptus, acacia, or beech) and softwoods such as spruce (trees of the genus Picea) or pine (trees of the genus Pinus). According to the invention, a hemicellulose-lignin complex derived from softwoods is preferred.

[0039] In a preferred embodiment of the invention, the lignin-hemicellulose complex is obtained by a process comprising the steps of:

[0040] (a) recovery of the liquor obtained in a wood treatment process selected from: a Kraft pre-hydrolysis process, a neutral sulfite scavenger (NSSC) process, a bisulfite process or a hydrothermal treatment (PHL), (b) ultrafiltration of the liquor,

[0041] (c) oxidation followed by radical polymerization of the hemicellulose contained in the liquid,

[0042] (d) removal of unpolymerized hemicellulose.

[0043] Step (a) consists of recovering the liquor obtained as a by-product during conventional pulp manufacturing processes, such as the Kraft process, the bisulfite process, or the neutral sulfite process (NSSC), or the liquor obtained after hydrothermal treatment of wood chips. In the Kraft process, the liquor is obtained after acid pre-hydrolysis of wood chips at 150–170°C. Alternatively, it may be the black liquor. In the bisulfite process, the liquor may also be obtained after hydrothermal treatment of wood chips. Alternatively, it may be the product of alkaline extraction at 110–140°C carried out (usually in the presence of calcium and / or magnesium) downstream of the kiln. The liquor from the neutral sulfite process (NSSC) is typically the exhausted liquor obtained after treating wood biomass with sodium sulfite and carbonate.For its part, the hydrothermal treatment can be, in particular, a thermomechanical treatment (TMP) or a chemical-thermomechanical treatment (CTMP). All these processes are implemented in a conventional manner for those skilled in the art. According to the invention, it is preferable to use the pre-hydrolysate obtained from a paper pulp manufacturing process, that is to say, a liquor obtained after hydrolysis of wood chips at 150-170°C. The liquor can be subjected to a filtration step in order to clarify it.

[0044] It is then subjected to an ultrafiltration step (b), for example using a membrane having a cut-off threshold of 1,000 to 15,000 Da, preferably 1,000 to 5,000 Da. The retentate is then recovered and its pH can be adjusted if necessary between 3 and 10, preferably between 5 and 7. This retentate contains hemicellulose bearing aromatic groups from the constituent monomers of lignin, namely p-coumaryl alcohol, coniferyl alcohol and synapyl alcohol, as well as hemicellulose lacking such aromatic groups.

[0045] This retentate is then subjected to an oxidation step (c). Oxidation can be carried out by chemical and / or enzymatic oxidation, preferably by enzymatic oxidation, notably using an oxidoreductase such as a peroxidase (associated with hydrogen peroxide) or a laccase (in the presence of oxygen), more preferably using a laccase. The enzyme may optionally be immobilized on a support. The enzyme is typically used at a temperature of 20–80°C, preferably 30–60°C, in an amount ranging, for example, from 13 to 14 U / g. This step leads to the formation of free radicals resulting in radical polymerization of the hemicellulose bearing aromatic groups to form a network referred to here as the hemicellulose-lignin complex.

[0046] The unpolymerized hemicellulose is then separated from the hemicellulose-lignin complex by any suitable technique, in particular by filtration, for example by tangential ultrafiltration using a membrane having a cutoff threshold of 30,000 Da, or by chromatography, in particular size exclusion chromatography (SEC).

[0047] This process, when applied to a liquor obtained from the Kraft prehydrolysis process, in particular, yields a lignin-hemicellulose complex comprising an anionic polymer in the form of block copolymers. The hemicellulose-lignin complex is used according to the invention in the manufacture of a resin. To this end, it is reacted with formaldehyde, optionally phenol, and optionally an amino compound selected from an alkanolamine and glycine, preferably glycine.

[0048] In a preferred embodiment, the resin is prepared according to a process comprising the following successive steps:

[0049] - a first condensation of the lignin-hemicellulose complex, and possibly phenol, with formaldehyde, in the presence of a basic catalyst, at a temperature ranging from 50 to 100°C,

[0050] - a second condensation with an amine compound chosen from an alkanolamine and glycine, according to the Mannich reaction, at a temperature of 50 to 75°C,

[0051] - the cooling of the reaction medium, and

[0052] - possibly, the addition of urea.

[0053] The first step of this process consists of the initial condensation of formaldehyde with the hemicellulose-lignin complex and optionally with phenol, in the presence of a basic catalyst. The catalyst can be chosen from those known to those skilled in the art, for example, triethylamine, lime, and hydroxides of alkali or alkaline earth metals, such as sodium, potassium, calcium, or barium hydroxides. Sodium hydroxide is preferred. In this step, either formaldehyde or a formaldehyde precursor such as paraformaldehyde can be used in the preparation of the reaction mixture. When phenol is present, the weight ratio of the hemicellulose-lignin complex to the mixture of hemicellulose-lignin complex and phenol is advantageously between 20% and 90%, preferably between 30% and 80%, and more preferably between 45% and 70%.In addition, the weight ratio of the amount of formaldehyde involved to the total amount of hemicellulose-lignin complex and phenol (when present) is advantageously between 1:1 and 1:12, preferably between 1:1.5 and 1:8. The first condensation reaction is carried out at a temperature ranging from 50 to 100°C, preferably from 55 to 75°C and more preferably from 60 to 70°C.

[0054] Following this initial condensation step, a second condensation is carried out with an amino compound, which is an alkanolamine or glycine, preferably glycine. This is done by adding the amino compound to the reaction mixture resulting from the first condensation, generally in a gradual manner to avoid any unwanted reaction with the hemicellulose-lignin complex, any phenol present, and formaldehyde (exothermic reaction). The amino compound can be added at a rate of 0.5 to 20% by weight per minute of the total amount of amino compound, preferably 1 to 10%, and advantageously 2.8 to 4%. The mass ratio of the amino compound to the mixture of hemicellulose-lignin complex and phenol is generally 0.1:1 to 0.5:1, preferably 0.1:1 to 0.3:1.

[0055] The temperature at the time of addition of the amine compound is kept constant during the second condensation with the compound, while ensuring that the water dilubility of the resin remains at least 1000%. To achieve this, the amine compound can be introduced at a temperature ranging from 50 to 75°C, preferably from 55 to 65°C. Maintaining the aforementioned temperature allows the amine compound to react with almost all of the formaldehyde present in the reaction medium and consequently reduces the free formaldehyde content in the final resin to a value of no more than 0.5% of the total resin weight, preferably no more than 0.3%, and advantageously no more than 0.1%. Maintaining the temperature mentioned above also reduces the free phenol content in the resin.

[0056] After the addition of the amine compound, the temperature is maintained constant for a further 10 to 180 minutes, preferably at least 30 minutes and advantageously 60 to 120 minutes, in order to continue the condensation reaction of the amine compound with the other reactants and to further reduce the amount of free formaldehyde and phenol, the water dilubility of the resin, measured at 20°C, being maintained at least equal to 1000%. The reaction medium is then cooled, for example to a temperature of about 20 to 25°C, preferably gradually at less than 2°C per minute, typically over a period of about 30 to 40 minutes.

[0057] This yields a resin with a water dilutability, measured at 20°C, of ​​at least 1000%, preferably at least 2000%, as measured in distilled water. Its viscosity is advantageously between 500 and 1500 mPa·s, preferably between 700 and 1000 mPa·s, as measured in the examples below.

[0058] The pH of the resin thus obtained is generally between 7.5 and 10, particularly between 8.0 and 9.5.

[0059] Up to 25% by weight, preferably between 10% and 20% by weight, of urea can then be added to the resulting resin. These quantities are expressed relative to the total dry weight of the resin and urea. The urea acts as a solubilizing agent and also helps to reduce the cost of the sizing compositions and the resulting products. Alternatively, urea derivatives, such as ethylene urea and 1,2-(hydroxyethyl)-2-imidazolidinone, can be used. However, it has been shown that the addition of urea or its derivatives is not essential and that the resin maintains stable dilubility over time even in the absence of these solubilizers.

[0060] The invention also relates to a gluing composition applicable to mineral fibers, preferably mineral wool fibers, in particular glass wool or rock wool fibers, as well as insulating products obtained from these glued fibers.

[0061] The sizing composition is an aqueous composition comprising the resin according to the present invention and optionally sizing additives. In cases where an amine compound has been used in the synthesis of the resin, as described above, it is preferable that the sizing composition also contain at least one compound containing at least one hydroxyl or amine functional group.

[0062] The aforementioned compound acts as a crosslinking agent; it is capable of reacting with the carboxyl groups of amine residues when the latter is used in resin synthesis, to form covalent bonds that contribute to the densification of the polymer network at the fiber junction points. Preferably, the aforementioned compound contains at least two hydroxyl and / or amine functional groups.

[0063] The crosslinking agent is preferably chosen from among saccharides, advantageously oligosaccharides containing up to 10 monosaccharide units, and even better monosaccharides, and primary or secondary amines. Preferably, glucose, hydrogenated sugars such as sorbitol or maltitol, glucose syrups, maltodextrins, urea, or a mixture of glucose and urea are chosen.

[0064] The quantity of crosslinking agent in the sizing composition varies, when present, from 1 to 40 parts by weight per 100 parts by weight of resin and said crosslinking agent, calculated on the basis of dry weight, preferably 10 to 30 parts.

[0065] Since the resin according to the invention has a very low free formaldehyde content, less than 0.5%, it is not necessary to add urea as an agent to trap formaldehyde in the sizing composition, unless it is necessary to control the gel time of the sizing composition in order to avoid possible pre-gelling problems.

[0066] The quantity of urea is at most equal to 25 parts by weight for 100 parts by weight of resin and urea, calculated on the basis of dry weight, and preferably does not exceed 10 parts.

[0067] In general, the gluing composition according to the invention may further include the following additives, per 100 parts by weight of resin and urea, where applicable, calculated on the basis of dry weight:

[0068] - 0 to 5 parts of ammonium sulfate and / or ammonium sulfamate, generally less than 3 parts,

[0069] - 0 to 2 parts silane, in particular an aminosilane,

[0070] - 0 to 20 parts oil, generally 6 to 15 parts,

[0071] - a silicone oil emulsion.

[0072] The role of the additives is well-established and briefly summarized: ammonium sulfate and ammonium sulfamate act as polycondensation catalysts (in the hot oven) after the sizing composition has been sprayed onto the fibers; silane acts as a coupling agent between the fibers and the resin, and also serves as an anti-aging agent; the oils act as dust suppressants and hydrophobic agents. Water can be added to the sizing composition before use to adjust its viscosity according to the intended application method, which is preferably spraying. Ideally, the sizing composition has a dry matter content of between 5 and 15% by weight.

[0073] After spraying the sizing composition onto the mineral fibers, the resulting product is heat-treated, typically in an oven, to evaporate the water and harden the resin to form an infusible binder.

[0074] This yields a thermal and / or acoustic insulation product, such as a mineral fiber veil or a mineral wool mat, advantageously a glass wool mat. This product advantageously exhibits a fire resistance loss of between 0.1% and 20%, preferably between 0.5% and 10%, and more preferably between 1% and 7% by weight.

[0075] The following examples illustrate the invention without limiting it.

[0076] EXAMPLES

[0077] The following analysis methods are used in the examples:

[0078] Viscosity: Viscosity was measured at 20°C, using a Brookfield DV2T viscometer equipped with an SC4-21 spindle.

[0079] Quantity of free phenol in the resin: it is measured by gas chromatography using a capillary column (stationary phase: Stabilwax® marketed by REZTK), an injector with flow divider ("split injector"), a flame ionization detector (FID) and a data acquisition system (Chemstation marketed by Agilent),

[0080] Quantity of free formaldehyde in the resin: Approximately 1 g of resin according to the invention is taken from a 100 mL volumetric flask, and the mass m taken is precisely recorded. The flask is then filled to the mark with distilled water. The free formaldehyde content is determined using a LANGE DR6000 colorimeter equipped with an LCK 325 formaldehyde quantification kit, following the supplier's instructions. The measurement is performed on 1 mL of the sample taken from the preparation flask. The result A obtained by the colorimeter is given in mg / L. The free formaldehyde content is calculated as follows:

[0081] % of free formaldehyde = (A x 0.1 ) / m x 100

[0082] The free formaldehyde content is given as a percentage of the sample, expressed to ± 0.01%. Any result below 0.01% is noted as < 0.01%.

[0083] Dilubility: The dilubility over time (or water tolerance) of the different resins according to the invention is evaluated as follows: 10 mL of the resin is poured into a 250 mL Erlenmeyer flask. 10 mL of water is added, the mixture is shaken, and the appearance of cloudiness is checked. When the solution remains clear after 30 seconds, another 10 mL of water is added, the mixture is shaken, and the clarity of the solution is again assessed. This cycle is repeated until a permanent cloudiness appears. The dilubility is calculated as follows:

[0084] Dilubility = (number of additions + 1) x 100

[0085] The resin is considered to have a dilubility of 2000% and to be infinitely dilutable when 19 times 10 mL of water have been added without the appearance of a cloudiness.

[0086] Tensile strength (Fmax): Fiberglass fabrics are impregnated in a bath of sizing compound pre-diluted in water to deposit approximately 8% binder onto the fibers, relative to the combined weight of the binder and fiberglass. The impregnated fabrics are baked for 120 seconds in a ventilated oven set at 215°C. For each test, the baked fabrics are cut into rectangular strips, which are then tested on an Instron 5960 series tensile testing machine, with the tensile direction at a 45° angle to the warp and weft. This measures the tensile strength (Fmax) of the binder joints.

[0087]

[0088] Synthesis of resins according to the invention

[0089] Three glycine-modified phenol-formaldehyde (P / F) resins were prepared in which phenol (P) was substituted in varying proportions with an LCC (Woodmer® Pulp from ECOHELIX), as shown in Table 1 below: Table 1

[0090]

[0091] The process for preparing these resins is detailed below.

[0092] Example 1A

[0093] A 100-milliliter reactor equipped with a condenser and a stirring system was loaded at 45°C with 28.7 g of LCC (47% concentration), 31.5 g of phenol (99% purity), 18.9 g of water, and 29.1 g (96% purity) of paraformaldehyde. The paraformaldehyde / phenol / LCC mass ratio was then 1.00:1.12:0.48.

[0094] 6.3 g of 50% dry matter sodium hydroxide were added at a constant rate to the medium for 30 minutes while the temperature was maintained at 45°C. The mixture was heated to 70°C with stirring for 2 hours, during which time the condensation reaction occurred. The temperature was then lowered to 60°C for 30 minutes, and simultaneously, glycine (98% purity) was introduced into the reaction mixture at a mass ratio of Glycine / (Phenol + LCC) of 0.235. The temperature was maintained at 60°C for 90 minutes, and then the mixture was cooled to approximately 20°C.

[0095] The resulting resin is clear, has a dry extract of 59%, a pH of 8.2, a viscosity of 800 mPa·s, and a dilubility in water at 20°C greater than 2000% in distilled water and in water containing 3% NaCl. The resin has a phenol content of 0.08% and a formaldehyde content of 0.19%.

[0096] Example 1B

[0097] A 2-liter reactor equipped with a condenser and stirring system was loaded at 45°C with 625 g of LCC (40% concentration), 250 g of phenol (99% purity), and 220 g of paraformaldehyde (96% purity). The paraformaldehyde / phenol / LCC mass ratio was 1.00:1.17:1.18. 67.9 g of 50% dry matter sodium hydroxide were added at a constant rate over 30 minutes while the temperature was maintained at 45°C. The mixture was then heated to 70°C with stirring for 2 hours, during which time the condensation reaction occurred. Next, the temperature was lowered to 60 °C for 30 minutes and simultaneously glycine (purity: 98%) was introduced into the reaction mixture at a mass ratio Glycine / (Phenol + LCC) of 0.118. The temperature was maintained at 60 °C for 90 minutes, then the mixture was cooled to about 20 °C.

[0098] The resulting resin is clear, has a dry extract of 57%, a pH of 9.4, a viscosity of 1010 mPa·s, and a dilubility in water at 20°C greater than 2000% in distilled water and in water containing 3% or 6% NaCl. The resin has a phenol content of 0.23% and a formaldehyde content of 0.06%. Furthermore, Resin 1B is observed to be stable in water containing 6% NaCl, as it retains a dilubility in water at 20°C greater than 2000% after 60 days of storage at 14°C.

[0099] Example 1 BC (comparative)

[0100] A 2-liter reactor equipped with a condenser and stirring system was loaded at 45°C with 570 g of phenol (purity: 99%), 469 g of paraformaldehyde (purity: 96%), and 550 g of water. The paraformaldehyde / phenol mass ratio was then 1.00:1.25. 79.9 g of 50% dry matter sodium hydroxide were added at a constant rate to the mixture for 30 minutes while the temperature was maintained at 45°C. The mixture was heated to 70°C with stirring for 2 hours, during which time the condensation reaction occurred. The temperature was then lowered to 60°C for 30 minutes, and simultaneously, glycine (purity: 98%) was introduced into the reaction mixture at a glycine / phenol mass ratio of 0.235. The temperature was maintained at 60°C for 90 minutes, then the mixture was cooled to approximately 20°C.

[0101] The resulting resin is clear, has a dry extract of 54%, a pH of 8.7, a viscosity of 74 mPa·s, and a water dilubility at 20°C greater than 2000% in distilled water and in water containing 3% or 6% NaCl. The resin has a phenol content of 0.02% and a formaldehyde content of 0.57%. The water dilubility at 20°C of this comparative resin (1B-C) dropped to 1500% after 60 days of storage at 14°C.

[0102] Example 1C

[0103] A 2-liter reactor equipped with a condenser and stirring system was loaded at 45°C with 875 g of LCC (40% concentration), 150 g of phenol (99% purity), and 148 g of paraformaldehyde (96% purity). The paraformaldehyde / phenol / LCC mass ratio was then 1.00:1.05:2.46. 67.3 g of 50% dry matter sodium hydroxide were added at a constant rate to the mixture over 30 minutes while the temperature was maintained at 45°C. The mixture was then heated to 70°C with stirring for 2 hours, during which time the condensation reaction occurred. Next, the temperature was lowered to 60 °C for 30 minutes and simultaneously glycine (purity: 98%) was introduced into the reaction mixture at a mass ratio Glycine / (Phenol + LCC) of 0.118. The temperature was maintained at 60 °C for 90 minutes, then the mixture was cooled to about 20 °C.

[0104] The resulting resin is clear, has a dry extract of 52%, a pH of 9.4, a viscosity of 825 mPa·s, and a water dilutability at 20°C greater than 2000% in distilled water and in water containing 3% or 6% NaCl. The resin has a phenol content of 0.11% and a formaldehyde content of 0.09%.

[0105]

[0106] Comparative study of the mechanical properties of resins

[0107] 75 parts of the resin from Example 1B were mixed with 25 parts of urea to obtain a resin designated hereafter as 1BU25. The viscosity of this resin was 257 mPa·s at pH 9.5. The dilubility in distilled water, 3% NaCl, and 6% NaCl was greater than 2000%. The dry matter content was 61%. The free phenol content was 0.21% and the free formaldehyde content was 0.05%.

[0108] The resin was stable for up to 2 weeks without a significant increase in its viscosity, while maintaining infinite dilubility in water with 3% NaCl added.

[0109] We then evaluated the mechanical properties of resins 1B and 1BU25, by comparison with the comparative resin prepared in Example 1, before and after the addition of 25 parts of urea for 100 parts of resin (respectively, resins 1 BC and 1B-CU25).

[0110] The results are presented in Table 2 below.

[0111] Table 2

[0112]

[0113] The mechanical properties of these resins were similar; the tensile strength and Young's modulus determined on resin-impregnated fiberglass fabrics were not significantly different.

[0114] Example 3: Preparing a sizing composition

[0115] The following sizing composition is prepared, in weight proportions relative to the dry extract:

[0116] - 75 parts of the resin from Example 1 B

[0117] - 25 parts of urea

[0118] - 9.1 parts of oil (Hydrowas 88®)

[0119] - 3 parts of ammonium sulfate

[0120] - 0.5 part of silane (gamma-aminopropyltriethoxysilane).

[0121] Example 4: Manufacturing and evaluating the properties of insulation products

[0122] Glass wool was manufactured in a pilot plant operating by internal centrifugation, and the sizing composition described in Example 3 was sprayed onto the glass fibers as they exited the fiber-pulling unit at a rate of 4.7% by dry weight of the sizing composition relative to the weight of the fibers. The sizing-coated fibers were collected on a conveyor belt where they formed a glass wool mat, which was then subjected to heat treatment in an oven to achieve a minimum core temperature of 200°C.

[0123] This resulted in a fiberglass mat that could be used as thermal insulation.

[0124] This mattress has been subjected to a series of tests designed to evaluate its mechanical properties, described below.

[0125] Tensile strength:

[0126] Tensile strength is measured using a mechanical test according to ASTM C686-71 T. A series of samples is stamped. Each sample is a ring with a length of 122 mm, a width of 46 mm, a radius of curvature of 38 mm on the outer edge, and a radius of curvature of 12.5 mm on the inner edge. The sample is placed between two cylindrical mandrels of a testing machine, one of which is mobile and moves at a constant speed. Tensile strength is the ratio of the breaking force F, measured in Newtons, to the mass M of the sample. The unit of tensile strength is the Newton-gram, or N·g. -1 .

[0127] Thickness increase:

[0128] The recovery in thickness after compression is evaluated in accordance with the standard NF EN 13162. It is considered satisfactory if it is between 95% and 115%.

[0129] Flexural strength:

[0130] Flexural strength is determined according to the ACERMI standard test for a 35 cm overhang under its own weight in a cantilevered position. The insulating product must exhibit a deflection of less than 120 mm in this test.

[0131] The results of these tests are presented in the table below.

[0132] Table 3

[0133]

[0134] As can be seen from this table, the products according to the invention exhibit the properties expected for an insulating product based on mineral wool.

Claims

Demands 1. Resin obtained from a reaction mixture comprising or consisting of: (a) a lignin-hemicellulose complex derived from wood, (b) formaldehyde, (c) possibly, phenol, (d) optionally, an amino compound selected from an alkanolamine and glycine.

2. Resin according to claim 1, characterized in that the lignin-hemicellulose complex is obtained by a process comprising the steps of: (a) recovery of the liquor obtained in a wood treatment process selected from: a Kraft pre-hydrolysis process, a neutral sulfite scavenger (NSSC) process, a bisulfite process or a hydrothermal treatment (PHL), (b) ultrafiltration of the liquor, (c) oxidation followed by radical polymerization of the hemicellulose contained in the liquid, (d) removal of unpolymerized hemicellulose.

3. Resin according to claim 2, characterized in that the oxidation is carried out by chemical and / or enzymatic oxidation, preferably by enzymatic oxidation, more preferably using a laccase.

4. Resin according to any one of claims 1 to 3, characterized in that the lignin and hemicellulose are linked, in the lignin-hemicellulose complex, by at least one benzyl ether, benzyl ester, phenyl glycosidic, ferulate ester and / or diferulate ester bond.

5. Resin according to any one of claims 1 to 4, characterized in that the hemicellulose-lignin complex contains: an amount of neutral monosaccharides, determined by chromatography after acid hydrolysis, which is greater than 5% by weight, preferably greater than 10% by weight, or even greater than 15% by weight, relative to the dry weight of the hemicellulose-lignin complex, and / or - an amount of Klason lignin, determined after acid hydrolysis, which is less than 60% by weight, preferably less than 50% by weight and more preferably less than 40% by weight, relative to the dry weight of the hemicellulose-lignin complex, and / or - a lignin / neutral monosaccharide weight ratio, determined by chromatography after acid hydrolysis, between 1.5 and 5, and / or - a quantity of phenolic groups carried by an aromatic ring, as determined by 31 P NMR, which is less than 4 mmol / g, preferably less than 3 mmol / g, or even less than 2 mmol / g, relative to the dry weight of the hemicellulose-lignin complex, and / or - a quantity of mannose, determined by chromatography after acid hydrolysis, which is greater than 10% by weight, preferably greater than 20% by weight, more preferably greater than 30% by weight, or even greater than 40% by weight, relative to the total dry weight of neutral monosaccharides in the hemicellulose-lignin complex.

6. A method for preparing the resin according to any one of claims 1 to 5, comprising the successive steps of: - a first condensation of the lignin-hemicellulose complex and possibly phenol, with formaldehyde, in the presence of a basic catalyst, at a temperature of 50 to 100°C, - a second condensation with an amine compound chosen from an alkanolamine and glycine, according to the Mannich reaction, at a temperature of 50 to 75°C, - the cooling of the reaction medium, and - possibly, the addition of urea.

7. A process according to claim 6, characterized in that, when phenol is present, the weight ratio of the hemicellulose-lignin complex to the mixture of hemicellulose-lignin complex and phenol is between 20% and 90%, preferably between 30% and 80%, more preferably between 45% and 70%.

8. A process according to any one of claims 6 to 7, characterized in that the mass ratio of the amino compound to the mixture of lignin-hemicellulose complex and phenol ranges from 0.1 / 1 to 0.5 / 1, preferably from 0.1 / 1 to 0.3 / 1.

9. Water-based sizing composition for mineral fibers, comprising a resin according to any one of claims 1 to 5 and optionally sizing additives.

10. Use of the gluing composition according to claim 9 for gluing mineral fibers, preferably glass wool or rock wool fibers, in order to form thermal and / or acoustic insulation products.

11. Insulation product, in particular thermal and / or acoustic, comprising mineral fibers, preferably glass wool or rock wool fibers, and a binder that can be obtained by baking the gluing composition according to claim 9.

Images