Binder composition free of phenol compounds

Abstract

To provide a binder composition that does not contain phenolic compounds. [Solution] A method for producing a binder composition without using a compound selected from the class of phenols is disclosed. This method comprises (i) heating an aqueous composition containing lignin and lignin oligomers at a temperature of 50 to 95°C for 0.25 to 5 hours in the presence of a catalyst, and (ii) mixing a crosslinking agent with the aqueous composition from (i) and heating the mixture at a temperature of 60 to 95°C to polymerize the lignin, lignin oligomers and crosslinking agent until a binder composition having a predetermined viscosity is formed, wherein the molar ratio of the crosslinking agent to the lignin and lignin oligomers is 0.5 to 1.8.

Description

Technical Field

[0001] The present invention relates to a method for producing a binder composition. Furthermore, the present invention relates to a binder composition, an adhesive composition, and the use of the binder composition and the adhesive composition.

Background Art

[0002] Lignin is a natural polymer that can be extracted from, for example, trees. The use of lignin as a component in adhesives instead of synthetic materials has been studied for the purpose of developing more environmentally friendly adhesive compositions. In particular, the ability to replace synthetic phenol derived from fossil resources in final phenolic resins such as phenol formaldehyde resins has been the subject of research.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the present inventor recognized the need for a method that provides a phenol-free binder composition for further uses.

Means for Solving the Problems

[0006] A method for producing a binder composition without using a compound selected from the class of phenols is disclosed. This method is (i) A step of heating an aqueous composition containing lignin having a weight-average molecular weight (Mw) of 2700 to 9000 g / mol and a lignin oligomer having a weight-average molecular weight (Mw) of 800 to 2500 g / mol at a temperature of 50 to 95°C for 0.25 to 5 hours in the presence of a catalyst, (ii) The process may include the step of mixing a crosslinking agent with the aqueous composition from (i) until a binder composition having a predetermined viscosity is formed, and heating the mixture at a temperature of 60 to 95°C to polymerize the lignin, lignin oligomer, and crosslinking agent, wherein the molar ratio of the crosslinking agent to the lignin and lignin oligomer is 0.5 to 1.8.

[0007] Furthermore, binder compositions that can be obtained by methods defined herein are disclosed.

[0008] Furthermore, an adhesive composition comprising a binder composition is disclosed.

[0009] Furthermore, the use of binder compositions in impregnation applications for the manufacture of laminates, shuttering films, mineral wool, nonwoven fiber products, molded fiber products, or extruded fiber products is disclosed for gluing wood products or laminated wood products or wood panels. [Modes for carrying out the invention]

[0010] A method for producing a binder composition without using a compound selected from the class of phenols is disclosed. This method is (i) A step of heating an aqueous composition containing lignin having a weight-average molecular weight (Mw) of 2700 to 9000 g / mol and a lignin oligomer having a weight-average molecular weight (Mw) of 800 to 2500 g / mol at a temperature of 50 to 95°C for 0.25 to 5 hours in the presence of a catalyst, (ii) The process may include the step of mixing a crosslinking agent with the aqueous composition from (i) until a binder composition having a predetermined viscosity is formed, and heating the mixture at a temperature of 60 to 95°C to polymerize the lignin, lignin oligomer, and crosslinking agent, wherein the molar ratio of the crosslinking agent to the lignin and lignin oligomer is 0.5 to 1.8.

[0011] Furthermore, binder compositions that can be obtained by methods defined herein are disclosed.

[0012] In one embodiment, the amount of free crosslinking agent in the binder composition, such as free formaldehyde monomer, is at most 1% by mass, at most 0.5% by mass, at most 0.3% by mass, at most 0.1% by mass, or at most 0.06% by mass. The amount of free crosslinking agent, such as free formaldehyde, can be determined according to standard EN-ISO 11402 and the procedure for hydroxylamine hydrochloride, except that the sample is diluted with 20 ml of distilled water and 70 ml of 94% ethanol.

[0013] In one embodiment, the amount of free phenol in the binder composition is less than 0.01% by mass, as determined by gas chromatography-flame ionization detector (GC-FID) according to standard SFS-EN ISO 8974:2002, except that the alkaline sample solution is diluted before neutralization.

[0014] In one embodiment, the water miscibility (tolerance) of the binder composition is greater than 500%, greater than 700%, greater than 900%, or infinite, as determined according to the standard EN ISO 8989.

[0015] In one embodiment, the viscosity value of the binder composition increases by at most 400 cP / 7 days, at most 300 cP / 7 days, at most 200 cP / 7 days, or at most 100 cP / 7 days when stored at 25°C after its manufacture. The binder compositions disclosed herein have the further advantage of exhibiting good storage stability.

[0016] The inventor has surprisingly found that the specified amount of the crosslinking agent and the molar ratio of the crosslinking agent to the polymerization components, namely lignin and lignin oligomers, affect the properties of the produced binder composition such that a binder composition having the above properties can be prepared.

[0017] Furthermore, an adhesive composition containing the binder composition is disclosed.

[0018] Furthermore, the use of the binder composition in impregnation applications for the production of laminates, shutter films, mineral wool, non-woven fiber products, molded fiber products or extruded fiber products, or for gluing wood products or laminated wood products or wood panels is disclosed.

[0019] Products produced by using the binder composition disclosed herein can have one or more of the following properties: - The formaldehyde emission is 0.01 - 0.5 mg / l, or 0.1 - 0.3 mg / l when measured by the desiccator method EN ISO 12460-4. - The formaldehyde emission is 0.01 - 0.40 mg / m 2 *h, or 0.05 - 0.30 mg / m 2 *h, or 0.1 - 0.2 mg / m 2 *h when measured by the gas analysis EN ISO 12460-3. - It meets a minimum bonding class of 1 - 4 or 2 - 4 or 3 - 4 when measured by the bonding quality test methods EN314-1 and EN314-2.

[0020] The inventor has surprisingly found that a binder composition can be produced by the method disclosed herein without using a compound selected from the class of phenols.

[0021] Unless otherwise specified, the term "compound selected from the class of phenols" should be understood to mean fossil-based compounds of phenols in this specification. That is, phenols are compounds consisting of a single aromatic ring to which one or more hydroxyl (-OH) groups are attached.

[0022] Such compounds selected from the class of phenols can be, for example, phenol, cresol or resorcinol. Such phenols are toxic compounds. In one embodiment, the method includes the condition that a compound selected from the class of phenols is not used to produce the binder composition. The method disclosed herein has the further utility of providing a method for producing a binder composition that does not contain fossil-derived materials. Thus, the produced binder composition may not contain fossil-based phenol compounds. In particular, the polymerizable substances used in the method, namely lignin and lignin oligomers, are derived from biomass or living organisms. Thus, the binder composition disclosed herein may be prepared as a non-toxic binder composition. That is, a binder composition with a reduced proportion of toxic or harmful compounds may be prepared. The binder composition disclosed herein may be prepared as a 100% biological binder composition.

[0023] The total amount of the crosslinking agent used to produce the binder composition may be 3 to 8% by mass, or 4 to 8% by mass, or 4 to 7% by mass, or 5 to 7% by mass based on the total mass of the binder composition.

[0024] Unless otherwise specified, the "total mass" in this specification should be understood as the mass of both the dry matter and the liquid part, such as water, of the binder composition.

[0025] The method disclosed herein has the further utility of being able to reduce or minimize the amount of crosslinking agent such as formaldehyde without adversely affecting the properties of the formed binder composition.

[0026] The crosslinking agent may be an aldehyde such as formaldehyde or paraformaldehyde. In one embodiment, the aldehyde is prepared from biomethanol. Therefore, the aldehyde may be of bio-based origin. Alternatively, the aldehyde may be of fossil origin. In one embodiment, the aldehyde is prepared from methanol.

[0027] The molar ratio of the crosslinking agent to lignin and lignin oligomer may be 0.9 to 1.7, or 1.0 to 1.6, or 1.1 to 1.7, or 1.2 to 1.6. In this specification, the molar ratio (MR) is defined as follows: MR = n(Fa) / (n(Lolig)+n(L)) (In the formula, n = amount of substance in moles Fa = Crosslinking agent Lolig = Lignin oligomer L = lignin) It is calculated as follows.

[0028] The amount of substance in moles is as follows: n = M / m (In the formula, Molar mass of a substance in units of M = g / mol m = the mass of the substance in grams. It is calculated as follows.

[0029] In this specification, the following values ​​are used in the above calculations: M (oligomer) = 180 g / mol (estimated value based on literature and assumed chemical structure) M (Lignin) = 180 g / mol (Estimated value based on literature and assumed chemical structure)

[0030] The mass ratio of lignin oligomers to lignin is 0.05 to 1.0, or 0.1 to 0.43, or 0.15 to 0.33.

[0031] The mass ratio of the catalyst to lignin and lignin oligomers is 0.20–0.37, or 0.22–0.35, or 0.26–0.33. The molar ratio of the catalyst to lignin and lignin oligomers may be 1.0–1.7, or 1.1–1.6, or 1.2–1.5. The amount of catalyst may have a beneficial effect on the properties of the prepared binder composition.

[0032] The catalyst may contain an alkali metal or alkaline earth metal salt or hydroxide. In one embodiment, the catalyst is selected from the group consisting of sodium hydroxide, potassium hydroxide, barium hydroxide, and combinations thereof. In one embodiment, the catalyst is sodium hydroxide.

[0033] The aqueous composition of step (i) may contain, consist of, or essentially consist of lignin and lignin oligomers in the presence of a catalyst.

[0034] Step (i) may include heating an aqueous composition containing lignin and lignin oligomers in the presence of a catalyst at a temperature of 50–95°C, or 55–95°C, or 60–95°C, or 65–90°C, or 70–85°C. Step (i) may be continued for 0.25–5 hours, or 2.5–4 hours, or 0.25–3 hours, or 0.5–2 hours, or 0.75–1.5 hours. During step (i), the lignin and lignin oligomers used are dissolved in the aqueous composition.

[0035] The temperature can be controlled during the manufacture of the binder composition by cooling and / or heating the aqueous composition.

[0036] In one embodiment, step (i) includes mixing the lignin oligomer with the aqueous composition before the lignin is added thereto. In one embodiment, step (i) includes mixing the lignin and the lignin oligomer essentially simultaneously with the aqueous composition.

[0037] The aqueous composition of step (ii) may contain, consist of, or essentially consist of the aqueous composition of (i) and a crosslinking agent.

[0038] Step (ii) may include heating at a temperature of 60-95°C, 75-90°C, 70-80°C, or 70-90°C. The heating in step (ii) may be continued until a binder composition having a viscosity value of 200-1000 cP or 250-600 cP, as measured at 25°C, is formed. In one embodiment, step (ii) is continued until a binder composition having a viscosity value of 200-500 cP, 250-400 cP, or 300-350 cP is formed. In one embodiment, step (ii) is continued until a binder composition having a viscosity value of 500-1000 cP, 500-800 cP, 550-750 cP, or 600-700 cP is formed.

[0039] Viscosity can be measured at a temperature of 25°C using a rotational viscometer (Brookfield Digital Viscometer LVDV-II+Pro; cone spindle). In one embodiment, step (ii) is continued for 0.5 to 8 hours, or 1 to 6 hours, or 2 to 5 hours.

[0040] Step (ii) may include the stepwise addition of catalysts; that is, additional amounts of catalyst may be added during step (ii) in addition to those used in step (i). Stepwise addition of catalysts has the added benefit of allowing the polymerization of lignin, lignin oligomers and crosslinking agents in a controlled manner. In one embodiment, step (ii) includes stepwise addition of catalysts and heating the resulting aqueous composition to polymerize lignin, lignin oligomers and crosslinking agents in a controlled manner.

[0041] In the context of this specification, the term “lignin” may refer to lignin derived from any suitable lignin source. In one embodiment, the lignin is essentially pure lignin. The expression “essentially pure lignin” should be understood as at least 70% pure lignin, or at least 90% pure lignin, or at least 95% pure lignin, or at least 98% pure lignin. Essentially pure lignin may contain at most 30%, or at most 10%, or at most 5%, or at most 2% of other components and / or impurities. Examples of such other components include extracts and carbohydrates such as hemicellulose.

[0042] In one embodiment, the lignin oligomer is an essentially pure lignin oligomer. The expression "essentially pure lignin oligomer" should be understood as a lignin oligomer that is at least 70% pure, or at least 80% pure, or at least 90% pure, or at least 95% pure, or at least 98% pure. An essentially pure lignin oligomer may contain at most 30%, or at most 10%, or at most 5%, or at most 2% of other components and / or impurities.

[0043] Lignin may contain less than 30% by mass, or less than 10% by mass, or less than 5% by mass, or less than 3% by mass, or less than 2.5% by mass, or less than 2% by mass, of carbohydrates. Lignin oligomers may contain less than 30% by mass, or less than 10% by mass, or less than 5% by mass, or less than 3% by mass, or less than 2.5% by mass, or less than 2% by mass, of carbohydrates. The amount of carbohydrates present in lignin can be measured by high-performance anion exchange chromatography (HPAE-PAD) with a pulsed amperometric detector according to standard SCAN-CM71.

[0044] The ash content of lignin may be less than 7.5% by mass, less than 5% by mass, less than 3% by mass, or less than 1.5% by mass. The ash content of lignin oligomers may be less than 15% by mass, less than 10% by mass, or less than 5% by mass. The ash content can be determined by the following method: First, determine the dry solids content of the sample by baking it in an oven at 105°C for 3 hours. Preheat a ceramic crucible to 700°C for 1 hour, and weigh it after cooling. Weigh the sample (1.5g to 2.5g) into the ceramic crucible. Place the lipped crucible in a low-temperature oven. Increase the oven temperature: 20-200°C for 30 minutes → 200-600°C for 60 minutes → 600-700°C for 60 minutes. Continue burning at 700°C for 60 minutes without a lid. Cool the crucible in a desiccator, add a few drops of hydrogen peroxide (H2O2, 30%) to the sample, and burn it in a 700°C oven for 30 minutes. If black spots are still present in the ash, repeat the hydrogen peroxide treatment and combustion. Cool the crucible and weigh it. All weighing should be done to an accuracy of 0.1 mg after cooling in a desiccator.

[0045] Calculation of the result Ash content%=(100 ax 100) / (bxc) During the ceremony, a = mass of ash, g b = mass of the sample, g c = dry solid content of the sample, %

[0046] The ash content of a sample refers to the mass remaining after combustion and annealing of the sample, and is expressed as a percentage of the dry content of the sample.

[0047] The ash content of a sample refers to the mass remaining after combustion and annealing of the sample, and is expressed as a percentage of the dry content of the sample.

[0048] The lignin used to prepare the binder composition may be selected from the group consisting of kraft lignin, steam explosion lignin, biorefinery lignin, supercritical separation lignin, hydrolyzed lignin, flash precipitated lignin, biomass-derived lignin, lignin from the alkali pulping process, lignin from the soda process, lignin from organosolve pulping, lignin from the alkali process, lignin from the enzymatic hydrolysis process, and any combination thereof. In one embodiment, the lignin is wood-derived lignin. The lignin may be derived from conifers, deciduous trees, annuals, or any combination thereof.

[0049] In this specification, "Kraft lignin" should be understood as lignin derived from Kraft black liquor unless otherwise specified. Black liquor is an alkaline aqueous solution of lignin residue, hemicellulose, and inorganic chemicals used in the kraft pulping process. Black liquor from the pulping process contains components derived from different coniferous and deciduous tree species in varying proportions. Lignin can be separated from black liquor by different techniques, including precipitation and filtration. Lignin typically begins to precipitate at pH values ​​below 11-12. Different pH values ​​can be used to precipitate lignin fractions with different properties. These lignin fractions differ from each other in terms of molecular weight distribution, e.g., Mw and Mn, polydispersity, hemicellulose, and extract content. The molar mass of lignin precipitated at higher pH values ​​is higher than that of lignin precipitated at lower pH values. Furthermore, the molecular weight distribution of lignin fractions precipitated at lower pH values ​​is broader than that of lignin fractions precipitated at higher pH values. The precipitated lignin can be purified from inorganic impurities, hemicellulose, and wood extracts using an acidic washing process. Further purification can be achieved by filtration.

[0050] In this specification, the term “flash-precipitated lignin” should be understood as lignin precipitated from black liquor in a continuous process by using a carbon dioxide-based acidifying agent, preferably carbon dioxide, to lower the pH of the black liquor stream to the lignin precipitation level under the influence of an overpressure of 200–1000 kPa, and then suddenly releasing the pressure necessary for lignin precipitation. A method for producing flash-precipitated lignin is disclosed in patent application FI20106073. The residence time in the above method is less than 300 seconds. Flash-precipitated lignin particles having a particle size of less than 2 μm form aggregates that can be separated from the black liquor, for example, by filtration. An advantage of flash-precipitated lignin is its higher reactivity compared to ordinary Kraft lignin. Flash-precipitated lignin can be purified and / or activated as needed for further processing.

[0051] Lignin may also be derived from an alkaline process. The alkaline process begins with liquefying the biomass with a strong alkali, followed by a neutralization process. After alkaline treatment, lignin can be precipitated in the same manner as described above.

[0052] Lignin may also be induced from a steam explosion. Steam explosion is a pulping and extraction technique applicable to wood and other fibrous organic materials.

[0053] In this specification, "biorefinery lignin" should be understood, unless otherwise specified, as lignin that can be recovered from refining facilities or processes in which biomass is converted into fuels, chemicals, and other materials.

[0054] In this specification, "supercritical separated lignin" should be understood, unless otherwise specified, as lignin that can be recovered from biomass using supercritical fluid separation or extraction techniques. Supercritical conditions correspond to temperatures and pressures exceeding the critical point of a given substance. Under supercritical conditions, there are no distinct liquid and gas phases. Supercritical water or liquid extraction is a method of decomposing biomass using water or liquid under supercritical conditions and converting it into cellulose sugars. The water or liquid acting as a solvent extracts sugars from the cellulose plant material, leaving lignin as solid particles.

[0055] Lignin may be derived from a hydrolysis process. Lignin derived from a hydrolysis process can be recovered from paper pulp or wood chemical processes.

[0056] The lignin may be derived from the organosolve process. Organosolve is a pulping technique that uses organic solvents to solubilize lignin and hemicellulose.

[0057] In one embodiment, the lignin is made of coniferous kraft lignin. In one embodiment, the lignin is coniferous kraft lignin having a weight-average molecular weight (Mw) of 2700 to 9000 g / mol, or 3000 to 8000 g / mol, or 3500 to 7000 g / mol.

[0058] In one embodiment, the lignin has a weight-average molecular weight of 3000 to 8000 g / mol, or 3500 to 7000 g / mol. The lignin, for example Kraft lignin, may have a polydispersity index of 2.9 to 6.0, or 3.0 to 5.0, or 3.2 to 4.5.

[0059] In one embodiment, the lignin is a combination of coniferous lignin and broadleaf tree lignin. In one embodiment, at most 30% by mass, at most 25% by mass, at most 10% by mass, or at most 5% by mass of the lignin is derived from broadleaf trees.

[0060] The weight-average molecular weight can be determined by gel permeation chromatography (GPC) with a UV detector (280 nm) using the following method: Dissolve the sample in 0.1 M NaOH. Filter the sample solution through a 0.45 micron PTFE filter. Measurement is performed using PSS MCX pre-columns, 1000 Å and 100000 Å columns and a sulfonated styrene-divinylbenzene copolymer matrix in 0.1 M NaOH eluent (0.5 ml / min, T=30°C). The molecular weight distribution of the sample is calculated with respect to polystyrene sulfonate sodium standards (6 samples) Mw891~65400. The values ​​Mw (weight-average molecular weight) and Mn (number-average molecular weight), and polydispersity index (PDI, Mw / Mn) are reported based on two parallel measurements.

[0061] The amount of alkali-insoluble matter in coniferous kraft lignin may be less than 10%, less than 5%, or less than 0.5%. The amount of alkali-insoluble matter can be determined by the following method: First, determine the dry solid content of the sample by baking it in an oven at 105°C for 3 hours. Dissolve 100g of the sample in 277g of NaOH aqueous solution (pH 12-13) and mix at 50-60°C for 30 minutes. Filter the solution through a glass filter using a Buchner funnel. Wash the residue on the filter with 0.1M NaOH and finally wash with water. Dry the filter containing the residue in an oven and weigh it. Then calculate the amount of alkali-insoluble matter as follows: Alkali-insoluble matter, % = [Mass of filter (dry) including residue (g) - Mass of filter] / [Mass of sample (g) * Dry solids content of sample (%)]

[0062] The amounts of condensation groups and syringyl groups in coniferous kraft lignin may be less than 3.0 mmol / g, or 2.5 mmol / g, or less than 2.0 mmol / g, as determined by 31P NMR. The amount of aliphatic OH groups in coniferous kraft lignin may be less than 3.0 mmol / g, or less than 2.5 mmol / g, as determined by 31P NMR. The amount of guaiacyl OH in coniferous kraft lignin may be at least 1.5 mmol / g, as determined by 31P NMR.

[0063] Measurements performed by 31P NMR spectroscopy after phosphytylation can be used to quantify functional groups (aliphatic and phenolic hydroxyl groups, and carboxylic acid groups). Sample preparation and measurement are carried out according to the method of Granata and Argyropoulos (Granata, A., Argyropoulos, D., J. Agric. Food Chem. 1995, 43:1538-1544). Accurately weighed sample (approximately 25 mg) is dissolved in N,N-dimethylformamide and mixed with pyridine and the internal standard solution (ISTD) endo-N-hydroxy-5-norbornene-2,3-dicarboximide (e-HNDI). Phosphytylation reagent (200 μl) 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphopholane is slowly added, and finally 300 μl of CDCl3 is added. Perform the NMR measurement immediately after adding the reagent. Measure the spectrum using a spectrometer equipped with a probe head optimized for broadband detection.

[0064] In one embodiment, the lignin oligomer is a coniferous lignin oligomer having a weight-average molecular weight of 800 to 2500 g / mol. In another embodiment, the lignin oligomer has a weight-average molecular weight of 1200 to 2400 g / mol, or 1400 to 2300 g / mol. The oligomer lignin may have a polydispersity index of 2.8 to 1.0, or 2.6 to 1.3, or 2.4 to 1.5.

[0065] Lignin may be depolymerized to reduce the molecular weight of the polymer in order to form low molecular weight lignin oligomers. Activity and reactivity may be increased simultaneously.

[0066] Therefore, lignin oligomers can be produced by the decomposition of lignin by different techniques, such as thermochemical or enzymatic degradation. The aromaticity of polymeric lignin is well known, and breakdown strategies, such as thermal and hydrocracking treatments, including catalytic hydrothermal degradation, hydrogenation, hydrothermal quality improvement, and base-catalyzed degradation (BCD), are applicable in industry. Such strategies aim to reduce molecular complexity, increase the chemical reactivity of the degradation products, and increase the degrees of freedom in chemical reactions. However, in all cases, such simple monomer structures (e.g., benzene, phenol, catechol, and pyrogallol from lignin) are not the main products of the breakdown process. Generally, two fractions are formed: monomers and oligomers. By-products include, for example, formic acid, acetic acid, methanol, and carbon dioxide.

[0067] The base-catalyzed decomposition process (BCD) is a more selective cleavage process compared to other lignin decomposition processes and does not require additional hydrogen. Decomposition is based on the catalytic cleavage of aryl-aryl-ether bonds (α-O-4, β-O-4, 4-O-5) by a strong base (e.g., sodium hydroxide) in high-temperature compressed water (subcritical and near-critical conditions, T=250-350°C). Treatment under milder conditions is also applicable. The cleavage process can be implemented in batch reactors, continuous-stirred tank reactors (CSTRs), or plugged-flow reactors (PFRs). Process parameters (e.g., T, τ, p, t, additives, catalysts) can be adjusted to guide the reaction and cleavage of methyl-aryl-ether bonds. By adjusting these parameters, the yield of lignin oligomers and the weight-average molecular weight of the lignin oligomer fraction can be adjusted and optimized to desired levels. Downstream processes, such as precipitation, filtration, liquid / liquid extraction, and evaporation, are used to produce the oligomeric lignin fraction. The oligomer-rich phase is a solid substance.

[0068] The exact sequence of steps for combining and / or adding the components necessary for the manufacture of the binder composition may vary, for example, depending on the required properties of the binder composition to be formed. The selection of the sequence of steps for combining and / or adding the necessary components is within the knowledge of those skilled in the art, as specified herein. The exact amounts of the components used to manufacture the binder composition may vary, and the selection of different component amounts is within the knowledge of those skilled in the art, as specified herein.

[0069] Furthermore, adhesive compositions comprising a binder composition disclosed herein are disclosed. In addition to the binder composition, the adhesive composition may include one or more adhesive components selected from the group consisting of other binders, fillers, additives, catalysts, and fillers. A binder is a substance primarily responsible for polymer growth and crosslinking, and thus assisting in the curing of the polymer system. A filler is a substance that assists the binder by modifying its physical properties, for example, by binding moisture. Additives may be polymers or inorganic compounds that assist in properties such as filling, softening, cost reduction, moisture control, increased stiffness, and increased flexibility. A catalyst is a substance that generally increases and modulates the curing rate. In this specification, “substance” should be understood to include compounds or compositions. The binder composition can function in the adhesive composition as a binder, filler, additive, catalyst, and / or filler.

[0070] Binder compositions, like adhesive compositions, can be used to glue wood products. In one embodiment, the wood product is selected from the group consisting of wood boards, wood veneers, and wood rods.

[0071] The methods disclosed herein have the further advantage of enabling the production of binder compositions without using, for example, phenol or any other compound selected from the class of phenols. The methods disclosed herein have the further advantage of enabling the production of phenol-free binder compositions having properties suitable for industrial applications, such as weight-average molecular weight and viscosity.

[0072] Furthermore, the binder compositions disclosed herein have the additional benefit of providing water resistance, stable adhesion, and / or low formaldehyde emissions to the final product manufactured using the binder compositions. [Examples]

[0073] Next, we will discuss various embodiments in detail.

[0074] The following description discloses some embodiments in enough detail to enable those skilled in the art to utilize them based on this disclosure. Not all processes or features of the embodiments are disclosed in detail, as many of them are obvious to those skilled in the art based on this specification.

[0075] (Example 1) Preparation of binder composition In this example, a lignin-lignin oligomer-formaldehyde binder composition was prepared.

[0076] The following ingredients and quantities were used: Water I 100% 1025kg NaOH (Part I) 50% 400kg Kraft Lignin 66.3% (Mw=5100g / mol) 1050kg 97% lignin oligomer (Mw=1890g / mol) 180kg NaOH (Part II) 50% 160kg Formaldehyde 37.5% 630kg

[0077] The percentages of the components used in this example (relative to the total dry matter content) were as follows: NaOH 50% 8.1% Kraft Lignin 66.3% 20.2% Lignin oligomer 97% 5.1% Formaldehyde 37.5% 6.9%

[0078] The molar ratio of NaOH to lignin and lignin oligomers was 1.45. The molar ratio of formaldehyde to lignin and lignin oligomers was 1.63.

[0079] First, water and the first part of NaOH were mixed at room temperature, and heating was started. When the temperature reached 75°C, lignin oligomer and lignin were added to the aqueous composition. Mixing and heating were continued for about 30 minutes while maintaining the temperature at approximately 90°C. After that, the temperature of the aqueous composition was cooled to approximately 60°C, and formaldehyde was added.

[0080] The formed aqueous composition was mixed and heated for 30 minutes, a portion of the NaOH was added, and the mixing and heating were continued for another 30 minutes, with the last portion of the NaOH being added. The mixing and heating of the formed composition was continued for approximately 1 hour while maintaining the temperature at approximately 75°C. The viscosity of the formed composition was 570 cP (measured at 25°C).

[0081] The formed binder composition had the following measurement characteristics: Solids content, % 35.7 (3 hours at 105°C) pH 12.5 Viscosity, cp 620 (at 25°C, after 3 days) Alkalinity, % 5.55 Free formaldehyde, % 0.11

[0082] (Example 2) Preparation of binder composition In this example, a lignin-lignin oligomer-formaldehyde binder composition was prepared.

[0083] The following ingredients and quantities were used: Water I 100% 675kg NaOH (Part I) 50% 190kg Kraft Lignin 69.6% (Mw=3900g / mol) 655kg 97% lignin oligomer (Mw=2100g / mol) 120kg NaOH (Part II) 50% 135kg Formaldehyde 37.5% 330kg

[0084] The percentages (relative to total mass) of the components used in this example were as follows: NaOH) 50% 7.7% Kraft Lignin 66.3% 21.7% Lignin oligomer 97% 5.5% Formaldehyde 37.5% 5.9%

[0085] The molar ratio of NaOH to lignin and lignin oligomers was 1.3. The molar ratio of formaldehyde to lignin and lignin oligomers was 1.30.

[0086] First, water and the first part of NaOH were mixed at room temperature, and heating was started. When the temperature reached 75°C, lignin oligomer and lignin were added to the aqueous composition. Mixing and heating were continued for 30 minutes while maintaining the temperature at approximately 90°C. After that, the temperature of the aqueous composition was cooled to approximately 60°C, and formaldehyde was added.

[0087] The resulting aqueous composition was mixed and heated for 30 minutes, then a portion of NaOH I was added. Mixing and heating were continued for another 60 minutes, and then a portion of NaOH II was added. The resulting composition was mixed and heated for approximately 45 minutes while maintaining a temperature of approximately 70°C. The viscosity of the resulting composition was 720 cP (measured at 25°C).

[0088] The formed binder composition had the following measurement characteristics: Solids content, % 37.1 (3 hours at 105°C) pH 12.6 Viscosity, cp 860 (at 25°C, after 3 days) Alkalinity, % 5.7 Free formaldehyde, % 0.04

[0089] (Example 3) Manufacturing of plywood products An adhesive composition was prepared using the binder composition prepared in Example 2. The adhesive composition was prepared by mixing the binder composition with wheat flour and limestone (1:1) and forming it in a 6 mm FC at 25°C for 70-100 seconds to reach a target viscosity. 3% sodium carbonate was used as a solidifying agent in this adhesive composition.

[0090] Subsequently, the formed adhesive composition was used to manufacture plywood products using birch veneer. 1.5 mm thick birch veneers were bonded with the adhesive composition to form 4.5 mm thick plywood panels. The dry matter content of the adhesive composition was 35-50%. The wood veneers containing the adhesive composition were pressed using hot pressing technology at a temperature of 130-170°C. The adhesive composition was cured simultaneously. The adhesive composition was found to be suitable for gluing wood veneers and therefore for manufacturing plywood. The results showed that the gluing effect of the adhesive composition was sufficiently good for gluing wood veneers and met the requirements of bond class 3 according to EN314-1 and EN314-2 standards and formaldehyde emission class El as measured by EN ISO 12460-3.

[0091] [Table 1]

[0092] As technology advances, it will be apparent to those skilled in the art that the basic idea can be implemented in various ways. Therefore, the embodiments are not limited to the examples described above, but may instead be modified within the scope of the claims.

[0093] The embodiments described herein can be used in any combination with one another. Several embodiments may be combined to form further embodiments. The methods, binder compositions, adhesive compositions, or uses disclosed herein may include at least one of the embodiments described herein. It is understood that the benefits and advantages described herein may relate to one embodiment or to multiple embodiments. Embodiments are not limited to solving any or all of the problems described or having any or all of the benefits and advantages described. It is further understood that a reference to an “an” item refers to one or more of those items. In this specification, the term “including” is used to mean including a subsequent feature or action without precluding the presence of one or more additional features or actions.

Claims

1. A method for producing a binder composition without using a compound selected from the class of phenols, (i) A step of heating an aqueous composition containing lignin having a weight-average molecular weight (Mw) of 2700 to 9000 g / mol and a lignin oligomer having a weight-average molecular weight (Mw) of 800 to 2500 g / mol at a temperature of 50 to 95°C for 0.25 to 5 hours in the presence of a catalyst, (ii) A method comprising the steps of (ii) mixing a crosslinking agent with the aqueous composition from (i) until a binder composition having a predetermined viscosity is formed, and heating the mixture at a temperature of 60 to 95°C to polymerize the lignin, lignin oligomer and crosslinking agent, wherein the molar ratio of the crosslinking agent to the lignin and lignin oligomer is 0.5 to 1.

8.

2. The method according to claim 1, wherein the total amount of crosslinking agent used to produce the binder composition is 3 to 8% by mass, or 4 to 8% by mass, or 4 to 7% by mass, or 5 to 7% by mass, relative to the total mass of the binder composition.

3. The method according to claim 1 or 2, wherein the molar ratio of the crosslinking agent to lignin and lignin oligomer is 0.9 to 1.7, or 1.0 to 1.6, or 1.1 to 1.7, or 1.2 to 1.

6.

4. The method according to any one of claims 1 to 3, wherein the mass ratio of the catalyst to lignin and lignin oligomer is 0.20 to 0.37, or 0.22 to 0.35, or 0.26 to 0.

33.

5. The method according to any one of claims 1 to 4, wherein the mass ratio of the lignin oligomer to lignin is 0.05 to 1.0, or 0.1 to 0.43, or 0.15 to 0.

33.

6. The method according to any one of claims 1 to 5, wherein step (ii) includes heating at a temperature of 75 to 90°C, or 70 to 80°C, or 70 to 90°C.

7. The method according to any one of claims 1 to 6, wherein the lignin is coniferous kraft lignin having a weight-average molecular weight (Mw) of 2700 to 9000 g / mol, or 3000 to 8000 g / mol, or 3500 to 7000 g / mol.

8. The method according to any one of claims 1 to 7, wherein the crosslinking agent is an aldehyde prepared from biomethanol.

9. The method according to any one of claims 1 to 8, wherein the heating in step (ii) is continued until a binder composition having a viscosity value of 200 to 1000 cP or 250 to 600 cP, as measured at 25°C, is formed.

10. A binder composition that can be obtained by the method described in any one of claims 1 to 9.

11. An adhesive composition comprising the binder composition described in claim 10.

12. Use of the binder composition according to claim 10 for gluing wood products or laminated wood products or wood panels, and for impregnation applications in the manufacture of laminates, shutter films, mineral wool, nonwoven fiber products, molded fiber products or extruded fiber products.

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