Sustainable wood adhesive formulations

Abstract

A formulation comprising: at least one isocyanate compound; at least one bio-oil-based compound selected from the group consisting of triglyceride (TG)-based bio-oil compounds and esterified bio-based fatty acid compounds; optionally, a catalyst compound for promoting urea / polyurethane formation; the ratio of the TG-based bio-oil compound to the esterified fatty acid compound is from 60 / 40 to 0 / 100, preferably from 55 / 45 to 0 / 100, more preferably from 50 / 50 to 40 / 60, most preferably from 45 / 55 to 50 / 50, and the at least one isocyanate compound (a) is present in an amount of at least 90 wt%, based on 100 wt% of the total formulation.

Description

Technical Field

[0001] The present invention relates to a sustainable isocyanate-based formulation or composition suitable as a wood adhesive composition, which provides cohesive strength to wood particles, chips or fibers and can be used in the production of wood-based composite panels such as particleboard (PB), oriented strand board (OSB) and wood fiber insulation board (WFI).

[0002] The present invention also relates to a sustainable isocyanate-based formulation or composition comprising an isocyanate fraction and a substantial biobased fraction.

[0003] Specifically, the present invention provides an isocyanate-based formulation that is storage-stable over time and can contain up to 25 wt% of biobased compounds (based on the total weight of the formulation), the biobased compounds being selected from triglyceride-based biooils and / or esterified fatty acids.

[0004] The present invention also relates to a method for preparing the sustainable isocyanate formulation of the present invention, the use of the formulation as a wood adhesive, and a lignocellulosic body prepared using the wood adhesive. Background Art

[0005] Amino resins such as urea formaldehyde resin (UF) are the most widely used wood adhesives due to their low cost and fast curing speed, especially in the production of particleboard. However, in addition to environmental and health problems, these UF-based resins also undergo hydrolytic degradation in the presence of moisture and / or acid. This degradation is mainly due to the hydrolysis of aminoplastics and methylene bridges. Typically, isocyanates (such as methylene diphenyl diisocyanate (MDI)) are added to UF resins to improve the performance of UF resins in terms of hydrolytic stability and mechanical properties (such as minimum strength, modulus, compression hardness and thickness swelling rate) and formaldehyde release.

[0006] Isocyanate-based resins themselves are also widely used as wood adhesives, and nowadays biobased materials are commonly used in the market to improve the sustainability of the resins and reduce the environmental impact of the resins.

[0007] However, isocyanate-based resins show very poor miscibility characteristics when blended / mixed with biobased materials such as triglyceride-based biooil compounds. Therefore, the amount of biobased compounds in isocyanate-based resins is limited because phase separation may occur during the mixing process, resulting in regions rich in biooil.

[0008] Poor miscibility of the components can also lead to a decrease in the reaction performance and inconsistency of the adhesive, as well as a decrease in the degree of conversion / crosslinking. Phase separation also affects the kinetics of gluing.

[0009] To maximize the amount of bio - oil - based compounds and minimize the poorly miscible characteristics, several methods have been explored previously. Currently, there are partial solutions.

[0010] For example, surfactants such as silicone are used to improve miscibility. However, this solution is not preferred because it causes plasticization problems, surfactant escape (migration to the surface), coatability after production, and potential adhesion / peeling problems.

[0011] Another method is to apply specialized mixing structures (high - shear, ultrasonic mixing, etc.) and / or apply higher mixing energy to better uniformly mix isocyanate droplets with bio - oil - based compounds. This solution is also not preferred because it requires special mixing equipment / structures. Additionally, the pot life of the mixture may be limited.

[0012] Another method is to pre - polymerize isocyanate with isocyanate - reactive bio - components such as bio - based polyols. However, this leads to an increase in resin viscosity and makes it impossible to handle the adhesive smoothly. A lower viscosity means that the adhesive composition can be more simply transported, for example, by pump between containers or storage tanks, and is easier to apply on the surface to be bonded.

[0013] Therefore, it is necessary to develop a synthesis method to prepare an isocyanate - based adhesive with a significantly increased amount of bio - oil - based compounds, thereby avoiding the problem of poor miscibility and maintaining the shelf - life and adhesive properties of the isocyanate - based adhesive without bio - oil - based compounds. Summary of the Invention

[0014] The object of the present invention is to develop a synthesis method to provide an isocyanate - based resin used as a wood adhesive, wherein the resin contains a large amount of bio - oil - based compounds, especially the bio - oil - based compound content is 25 wt% or more based on the total weight of the resin.

[0015] The object of the present invention is to provide an adhesive formulation containing 10 - 25 wt% bio - oil - based compounds (based on the total weight of the resin), the formulation having stability and good processing properties and can be further processed into a wood - based material with good performance curves, especially when the wood - based material is required to have high mechanical load - bearing performance.

[0016] The present inventors have now surprisingly found that this objective can be achieved by a formulation comprising at least one isocyanate compound and up to 25 wt% of a bio-oil-based compound, wherein the bio-oil-based compound is selected from triglyceride (TG)-based bio-oil compounds and esterified fatty acid compounds, and wherein the ratio of the TG-based bio-oil compound to the esterified bio-based fatty acid compound is from 60 / 40 to 0 / 100, preferably from 55 / 45 to 0 / 100, more preferably from 50 / 50 to 40 / 60, and most preferably from 45 / 55 to 50 / 50. This formulation provides good miscibility of the bio-oil-based compound with the isocyanate compound and is stable over time (good shelf life), and the processing characteristics are comparable to those of an isocyanate-based wood adhesive formulation without the addition of a bio-oil-based compound, such as speed and characteristics of critical panels (adhesion strength, restricted swelling, etc.). A system with better miscibility and greater compatibility can improve the overall performance of this mixed adhesive system.

[0017] Accordingly, the present invention relates to isocyanate-based resins containing 10-25 wt% of a bio-oil-based compound, and to the use of these isocyanate-based resins as wood adhesive compositions, which provide cohesive strength to wood particles, chips or fibers and are capable of producing wood composite panels such as particle board (PB), oriented strand board (OSB) and wood fiber insulation board (WFI).

[0018] Definitions and Terms

[0019] In the context of the present invention, the following terms have the following meanings:

[0020] 1) The term "isocyanate index" or "NCO index" or "index" as used herein refers to the ratio between the NCO groups and the isocyanate-reactive hydrogen atoms in the formulation, expressed as a percentage:

[0021] [NCO]x100 (%)

[0022] [Active hydrogen]

[0023] In other words, the NCO-index represents the percentage between the amount of isocyanate actually applied in the formulation relative to the amount of isocyanate theoretically required for the reaction with the isocyanate-reactive hydrogen present in the formulation.

[0024] The NCO values shown in the examples were measured using a titration-based measurement method. The isocyanate reacts with an excess of di-n-butylamine to form urea. The unreacted amine is then titrated with standard nitric acid to the color change of the bromocresol green indicator or the potentiometric end point. The NCO percentage or NCO value is defined as the weight percentage of NCO groups present in the product.

[0025] In addition, it should be observed that the isocyanate index applied herein is considered from the perspective of the actual polymerization process for preparing materials comprising an isocyanate component and an isocyanate-reactive component. When calculating the isocyanate index, any isocyanate groups consumed in the initial steps of producing modified polyisocyanates (including derivatives of such isocyanates known in the art as prepolymers) are not considered, nor are any active hydrogens consumed in the initial steps (such as reacting with isocyanates to produce modified polyols or polyamines). Only the free isocyanate groups and free isocyanate-reactive hydrogens (including the reactive hydrogen of water if applied) present in the actual polymerization stage are considered.

[0026] 2) As used herein, the term "triglyceride" (TG) is defined as an ester derived from glycerol and three carboxylic acids having aliphatic chains with an even number of 4 - 28 carbon atoms per molecule. Carboxylic acids having aliphatic chains with an even number of 4 - 28 carbon atoms per molecule are commonly referred to as fatty acids. Triglycerides are typically formed from fatty acids having 16 or 18 carbon molecules on each aliphatic chain. Triglycerides that can be applied in the present invention can be vegetable oils. Vegetable oils can be partially or fully hydrogenated or used without hydrogenation. Examples of vegetable oils include, but are not limited to, soybean oil, rapeseed oil, sunflower oil, canola oil, safflower oil, herring oil, corn oil, olive oil, cocoa butter, linseed oil, cottonseed oil, peanut oil, palm oil, jatropha oil, algal oil, coconut oil, and mixtures thereof.

[0027] 3) The terms "modulus of elasticity" or "MOE" and "modulus of rupture" or "MOR" as used herein are in units of MPa and are measured in accordance with BS 310 (Determination of the modulus of elasticity in flexure and bending strength). The flexural modulus of elasticity and the flexural strength are measured by applying a load to the center of a test piece supported at two points. The modulus of elasticity is calculated by applying the slope of the linear region of the load-deflection curve; the calculated value is the apparent modulus rather than the true modulus because the test method includes shear and bending. The flexural strength of each test piece is calculated by determining the ratio of the bending moment M at the maximum load Fmax to the moment of inertia of the full cross-section.

[0028] 4) The "tensile strength" as used herein refers to the "internal bond (IB) strength", which is in units of MPa and is measured in accordance with BS 319 (Measurement of tensile strength perpendicular to the plane of the board). The test piece is placed under a uniformly distributed tensile force until it breaks, and the tensile resistance perpendicular to the surface of the test piece is determined. The tensile strength perpendicular to the plane of the wooden board is determined by the maximum load related to the surface area of the test piece.

[0029] 5) The term "thickness swelling rate" as used herein is expressed in % and is measured in accordance with BE EN 317 (Measurement of the swelling of thickness after soaking in water for a predetermined time). The thickness swelling rate is determined by measuring the increase in the thickness of the test piece after complete immersion in water.

[0030] 6) The term "pressure factor" as used herein is calculated in s / mm and refers to the time of the board in the press at a certain temperature and for a certain board thickness.

[0031] 7) The terms "isocyanate-reactive compound", "NCO-reactive compound", "isocyanate-reactive hydrogen atom", and "isocyanate-reactive group" as used herein refer to the active hydrogen atoms in the hydroxyl and amine groups present in isocyanate-reactive compounds. A compound having one hydroxyl group is considered to contain one reactive hydrogen, a compound having a primary amine group is considered to contain one reactive hydrogen, and a water molecule is considered to contain two reactive hydrogens.

[0032] 8) Unless otherwise specified, the term "average" as used herein refers to number average.

[0033] 9) The term "fatty acid" as used herein is a carboxylic acid having an aliphatic chain, which may be saturated or unsaturated. A "bio-based fatty acid" is a fatty acid derived from natural fatty acids. The fatty acids of the present invention preferably have an unbranched chain of 4-28 carbon atoms.

[0034] 10) The "esterified fatty acid" or "fatty acid ester" as used herein is a reaction product of a fatty acid and an alcohol. The "bio-based esterified fatty acid" as used herein is an esterified fatty acid derived from natural fatty acids. Examples of suitable esterified fatty acids are methyl linoleate (also known as methyl linoleate), which are common methyl esters produced by the reaction of soybean oil or canola oil with methanol. Another suitable example of an esterified fatty acid is rapeseed methyl ester (RME), which is a reaction product of the natural fatty acids in rapeseed oil and methanol. Detailed Description

[0035] The present invention will be described in connection with specific embodiments.

[0036] It should be noted that the term "comprising" as used in the claims should not be construed as being limited to the facilities listed subsequently; it does not exclude other elements or steps. Thus, the term "comprising" should be interpreted as specifying the presence of the stated features, steps, or components, but not excluding the presence or addition of one or more other features, steps, or components or combinations thereof. Thus, the scope of the expression "a compound comprising components X and Y" should not be limited to compounds consisting only of components X and Y. This means that for the present invention, the only relevant components of the compound are X and Y.

[0037] Throughout the specification, when reference is made to "an embodiment" or "embodiments", such reference means that at least one embodiment of the invention includes a particular feature related to the embodiment. Thus, the phrases "in one embodiment" or "in embodiments" that appear throughout this specification are not necessarily all referring to the same embodiment, but may be. Additionally, specific features or characteristics may be combined in any suitable manner in one or more embodiments, as will be apparent to those of ordinary skill in the art.

[0038] It is understood that although preferred embodiments and / or materials for providing embodiments of the invention have been discussed, various adjustments or changes can be made without departing from the scope and essence of the invention.

[0039] According to the present invention, a stable isocyanate-based formulation suitable for use as a wood adhesive is disclosed, wherein the formulation comprises up to 25 wt% of a bio-oil-based compound selected from triglyceride (TG)-based bio-oil compounds and esterified bio-based fatty acid compounds, and wherein the ratio of the TG-based bio-oil compound to the esterified fatty acid compound is less than 60 / 40, preferably from 55 / 45 to 0 / 100, more preferably from 40 / 60 to 50 / 50, and most preferably a ratio of 50 / 50.

[0040] Accordingly, the present invention provides a formulation comprising:

[0041] - at least one isocyanate compound; and

[0042] - at least one bio-oil-based compound selected from triglyceride (TG)-based bio-oil compounds and esterified bio-based fatty acid compounds, and

[0043] - optionally a catalyst for promoting urea / polyurethane formation,

[0044] - optionally additional auxiliary compounds and / or additives,

[0045] characterized in that the ratio of the TG-based bio-oil compound to the esterified fatty acid compound is less than 60 / 40, preferably from 55 / 45 to 0 / 100, more preferably from 40 / 60 to 50 / 50, and most preferably a ratio of 50 / 50.

[0046] According to some embodiments, based on the total weight of all bio-oil-based compounds in the formulation selected from triglyceride (TG)-based bio-oil compounds and esterified bio-based fatty acid compounds, the amount of the TG-based bio-oil compound in the formulation of the present invention is 0 - 60 wt%, preferably 0 - 55 wt%, more preferably 40 - 50 wt%.

[0047] According to some embodiments, based on the total weight of all bio-oil-based compounds selected from triglyceride (TG)-based bio-oil compounds and esterified bio-based fatty acid compounds in the formulation, the amount of TG-based bio-oil compounds in the formulation of the present invention is 10-55 wt%, preferably 20-55 wt%, more preferably 40-50 wt%.

[0048] According to some embodiments, based on the total weight of all bio-oil-based compounds selected from triglyceride (TG)-based bio-oil compounds and esterified bio-based fatty acid compounds in the formulation, the amount of TG-based bio-oil compounds in the formulation of the present invention is 50 wt%.

[0049] According to some embodiments, the formulation of the present invention contains only esterified bio-based fatty acid compounds and does not contain TG-based bio-oil compounds.

[0050] The formulation of the present invention is suitable for use as an adhesive and maintains processing performance, speed, and main panel characteristics (such as but not limited to bond strength, avoidance of swelling, moisture resistance, etc.).

[0051] The formulation of the present invention contains a large number of bio-based compounds derived from bio-oil, and due to the specific ratio of its TG-based bio-oil compounds to esterified fatty acid compounds, the formulation has stable characteristics, has the required viscosity characteristics (<150-160 mPa·s), and does not cause phase separation. Generally, a lower viscosity allows the adhesive formulation to be better distributed on wood.

[0052] Another characteristic of the formulation of the present invention is that it has a lower density compared to prior art isocyanate-based adhesives, resulting in a larger volume of adhesive being applied to wood when applied at a similar weight loading.

[0053] At least one isocyanate compound of the formulation of the present invention comprises at least one isocyanate. In one embodiment, the at least one isocyanate includes a polyisocyanate compound. Non-limiting examples of suitable polyisocyanates that can be used in the present invention can be any organic polyisocyanate compound or a mixture of organic polyisocyanate compounds, wherein the compounds preferably have at least two isocyanate groups. Non-limiting examples of organic polyisocyanates include diisocyanates (especially aromatic diisocyanates) and isocyanates with a higher functionality. Non-limiting examples of organic polyisocyanates that can be used in the formulation of the present invention include: aliphatic isocyanates such as hexamethylene diisocyanate; and aromatic isocyanates such as diphenylmethane diisocyanate (MDI) in its 2,4', 2,2' and 4,4' isomer forms and mixtures thereof (also referred to as pure MDI), mixtures of diphenylmethane diisocyanate (MDI) and their oligomers (referred to in the art as "crude" or polymeric MDI), meta- and para-phenylene diisocyanate, toluene-2,4- and toluene-2,6-diisocyanate in any suitable isomer mixture form (also referred to as toluene diisocyanate and called TDI, such as 2,4-TDI and 2,6-TDI), m-chlorobenzene-2,4-diisocyanate, naphthalene-1,5-diisocyanate, diphenylene-4,4'-diisocyanate, 4,4'-diisocyanate-3,3'-dimethyl-diphenyl, 3-methyl-diphenylmethane-4,4'-diisocyanate and diphenyl ether diisocyanate; and cycloaliphatic diisocyanates such as cyclohexane-2,4- and -2,3-diisocyanate, 1-methylcyclohexyl-2,4- and -2,6-diisocyanate and mixtures thereof, and bis-(isocyanatocyclohexyl)methane (e.g., 4,4'-diisocyanatodicyclohexylmethane (H12MDI)), triisocyanates such as 2,4,6-triisocyanatotoluene and 2,4,4-triisocyanatodiphenyl ether, isophorone diisocyanate (IPDI), butylene diisocyanate, trimethylhexamethylene diisocyanate, isocyanatomethyl-1,8-octane diisocyanate, tetramethylxylene diisocyanate (TMXDI), 1,4-cyclohexane diisocyanate (CDI) and toluidine diisocyanate (TODI).

[0054] In one embodiment, at least one isocyanate can be an emulsifiable polyisocyanate. Suitable emulsifiable isocyanates can be any of the emulsifiable MDIs, such as those disclosed in the following patent publications: EP 18061, EP 516361, GB 1523601, GB 1444933, GB 2018796, all of which are incorporated herein by reference. A class of suitable emulsifiable MDIs includes those products obtained by pre-reacting a polyisocyanate (especially polymeric MDI) with a small amount of an alkoxypolyalkylene glycol (such as an alkoxypolyalkylene glycol in which one diol - OH group is converted to an alkoxy group by reaction with a lower alcohol such as methanol and / or ethanol), and such products are mixtures of a polyisocyanate and a small amount of a non-ionic surfactant formed by the reaction between the polyisocyanate and the alkoxypolyalkylene glycol. The self-emulsifiable polyisocyanate can be based on any organic polyisocyanate, such as a low functionality MDI variant, such as uretonimine-modified MDI, but is preferably based on a mixture called polymethylene polyphenyl polyisocyanate or polymeric MDI. The alkoxypolyalkylene glycols that can react with the polyisocyanate to form a self-emulsifiable polyisocyanate include alkoxypolyethylene glycols, such as those having a molecular weight of 250 - 4000, especially 600 - 2000. The alkoxy group suitably contains 1 - 6 carbon atoms, and is preferably methoxypolyethylene glycol. Suitable emulsifiable polyisocyanates are commercially available from Huntsman under the trade names 1042, 2405, 2408 and 2419 ( is a trademark of Huntsman LLC).

[0055] In one embodiment, at least one isocyanate can be selected from 2,4'- 2,2'- and 4,4'-MDI isomers and their homopolymers or mixtures, mixtures of 2,4', 2,2' and 4,4'-methylenediphenyl diisocyanates and their oligomers. In one embodiment, at least one isocyanate is selected from 2,2'- or 4,4'-MDI, their homopolymers and mixtures, or mixtures of 2,2' and 4,4'-methylenediphenyl diisocyanates and their oligomers. In one embodiment, at least one isocyanate is selected from 4,4'-MDI or its homopolymer.

[0056] In the preferred polyisocyanate composition of the present invention, the polyisocyanate is an aromatic diisocyanate or a polyisocyanate with a higher functionality, in particular a crude mixture of methylene-bridged polyphenyl polyisocyanates containing diisocyanates, triisocyanates and polyisocyanates with a higher functionality. Methylene-bridged polyphenyl polyisocyanates (such as methylene diphenyl diisocyanate, abbreviated as MDI) are well-known in the art and have the general formula I, where n is one or more, and represents an average value greater than 1 in the crude mixture. They are prepared by the phosgenation reaction of the corresponding polyamine mixture obtained by the condensation of aniline and formaldehyde.

[0057]

[0058] Other suitable polyisocyanate compositions may include isocyanate-terminated prepolymers prepared by reacting an excess of diisocyanate or a polyisocyanate with a higher functionality with a hydroxyl-terminated polyester or a hydroxyl-terminated polyether, and products obtained by reacting an excess of diisocyanate or a polyisocyanate with a higher functionality with a monomeric polyol or a mixture of monomeric polyols (such as ethylene glycol, trimethylolpropane or butanediol). A preferred class of isocyanate-terminated prepolymers is isocyanate-terminated prepolymers of a crude mixture of methylene-bridged polyphenyl polyisocyanates containing diisocyanates, triisocyanates and polyisocyanates with a high functionality. The NCO content of the preferred prepolymers is 5-30%, preferably 10-28%, and particularly preferably 15-25 wt%. Their viscosity at 25 °C is 300-10,000 mPa·s, preferably 500-2,000 mPa·s.

[0059] The polyisocyanate mixture can be produced by any technique known in the art. The isomer content of diphenylmethane diisocyanate can be adjusted to the required range by techniques known in the art if necessary. One technique for changing the isomer content is to add monomeric MDI to an MDI mixture containing a higher amount of polymeric MDI than required.

[0060] In one embodiment, at least one isocyanate includes any suitable mixture of any of the above polyisocyanates, or any suitable mixture of one or more of the above polyisocyanates and an MDI-type polyisocyanate.

[0061] In some embodiments, based on 100 wt% of the total formulation, the amount of at least one isocyanate present can be at least 70 wt%. For example, based on the total weight (100 wt%) of the formulation, the amount of at least one isocyanate present in the formulation can be at least 75 wt%, such as at least 80 wt%, such as at least 85 wt%. For example, based on the total weight (100 wt%) of the formulation, the amount of at least one isocyanate present can be 70-90 wt%, such as 75-85 wt%, such as 75-80 wt%.

[0062] According to some embodiments, the triglyceride (TG)-based bio-oil compounds are selected from linseed oil, soybean oil, palm kernel oil, sunflower oil, corn oil, cottonseed oil, perilla oil, rapeseed oil, olive oil and / or canola oil, palm oil, coconut oil, rice bran oil, safflower oil, sesame oil, tall oil, and mixtures thereof.

[0063] Examples of bio-based fatty acids derived from bio-oil and suitable for preparing esterified fatty acid compounds are caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, myristoleic acid, palmitoleic acid, eleostearic acid, oleic acid, elaidic acid, isolenic acid, linoleic acid, elaidolinoleic acid, (α)-linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, docosahexaenoic acid.

[0064] According to a preferred embodiment, the bio-based fatty acids for preparing esterified fatty acid compounds include but are not limited to caprylic acid, capric acid, lauric acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, palmitoleic acid, linoleic acid, linolenic acid, oleic acid, erucic acid, and mixtures thereof. Preferred esterified fatty acid compounds are derived from linoleic acid, linolenic acid, and oleic acid.

[0065] Suitable examples of esterified bio-based fatty acid compounds are mixtures of methyl esters of saturated and unsaturated C16-C22 fatty acids derived from rapeseed oil, also known as rapeseed methyl ester (RME).

[0066] In some embodiments, the formulation may further comprise at least one additive selected from the group consisting of hardeners, surfactants, mold release agents, waxes, or pigments.

[0067] In some embodiments, based on the total weight (100 wt%) of the formulation, the amount of the additive present may be at least 0.01 wt%, such as at least 0.03 wt%, such as at least 0.1 wt%, preferably at least 0.3 wt%, preferably at least 1 wt%.

[0068] In one embodiment, the additive is a surfactant. Non-limiting examples of surfactants are silicones. Non-limiting examples of waxes are soft waxes or emulsifying waxes. Non-limiting examples of suitable pigments include titanium dioxide, zinc borate, oxalates, mica, perlite, clay, and silica.

[0069] According to some embodiments, the additive is a hardener, also known as a polyurethane-forming catalyst compound. Polyurethane-forming catalyst compounds suitable for use herein include, but are not limited to, metal salt catalysts such as organotin, and aliphatic and aromatic tertiary amine compounds such as triethylenediamine (TEDA), N-methylimidazole, 1,2-dimethylimidazole, N-methylmorpholine, N-ethylmorpholine, triethylamine, N,N'-dimethylpiperazine, 1,3,5-tris(dimethylaminopropyl)hexahydrotriazine, 2,4,6-tris(dimethylaminomethyl)phenol, N,N-dimethylcyclohexylamine, pentamethyldipropylenetriamine, N-methyl-N'-(2-dimethylamino)ethyl-piperazine, tributylamine, pentamethyldiethylenetriamine, hexamethyltriethylenetetramine, heptamethyltetraethylenepentamine, dimethylaminocyclohexylamine, pentamethyldipropylenetriamine, triethanolamine, dimethylethanolamine, bis(dimethylaminoethyl)ether, tris(3-dimethylamino)propylamine or its acid-capped derivatives, etc., and any mixtures thereof. The catalyst compound should be present in a catalytically effective amount.

[0070] The present invention also includes a method for preparing the above-mentioned formulation, the method comprising the step of mixing at least one isocyanate compound, at least one bio-oil-based compound selected from triglyceride (TG)-based bio-oil compounds and esterified fatty acid compounds, an optional catalyst for promoting urea / polyurethane formation, and an optional one of the above-mentioned other auxiliary compounds and / or additives, thereby obtaining the above-mentioned formulation.

[0071] The present invention also includes the use of the formulation or composition of the present invention as an adhesive. The formulation or composition is particularly suitable for use as an adhesive for materials containing lignocellulose (also referred to herein as "lignocellulosic materials").

[0072] Non-limiting examples of lignocellulosic materials include waste products such as wood wool, wood chips, wood fibers, wood shavings, wood veneer, wood hairs, cork, bark, sawdust, etc. in the wood processing industry, and other materials based on lignocellulose, such as paper, bagasse, straw, flax, sisal, bamboo, coconut fiber, hemp, rush, reed, rice husk, husk, grass, nut shell, etc. Additionally, the lignocellulosic material can be mixed with other particulate or fibrous materials, such as ground foam waste (e.g., ground polyurethane foam waste), mineral fillers, glass fibers, mica, rubber, textile waste such as plastic fibers and fabrics. The lignocellulosic material can be used in the form of granules, wood shavings or fragments, fibers, threads, spheres or powders. The lignocellulosic material preferably includes wood.

[0073] The present invention also includes using the formulation or composition of the present invention to bond at least one lignocellulose-containing product, also referred to herein as a "lignocellulosome". The formulation or composition of the present invention is also particularly suitable for repairing lignocellulosomes.

[0074] The present invention also includes a method for bonding lignocellulosic materials, the method comprising coating the lignocellulosic materials with the formulation or composition of the present invention and curing the formulation or composition.

[0075] The present invention also includes a substrate comprising the adhesive formulation or composition of the present invention.

[0076] The present invention also includes a lignocellulosic body prepared by applying the formulation or composition of the present invention.

[0077] The method for preparing the lignocellulosic body of the present invention can be carried out as follows: contacting the lignocellulosic materials with the formulation or composition of the present invention, for example, by mixing, spraying and / or applying the formulation or composition onto the lignocellulosic materials and pressing the lignin materials, the pressing being preferably by hot pressing, for example, at a temperature of 120 - 300 °C, preferably 140 - 270 °C and at a specific pressure of, for example, 2 - 6 MPa. The lignocellulosic materials treated with the formulation or composition of the present invention can be placed on a separator made of aluminum or steel, and the separator is used to send the raw materials to a press, where they are usually compressed to the desired degree at a temperature of 120 - 300 °C, preferably at a temperature of 140 - 270 °C. At the start of production, it may be helpful, but not necessary, to adjust the press plates by spraying an external release agent on the surface of the press plates or increasing the cycle time of the first ballast. Then the pre-adjusted press can be used multiple times in the method of the present invention without further treatment.

[0078] Non-limiting examples of lignocellulosic bodies include oriented strand board (OSB), structural composite lumber (SCL), wafer board, fiberboard, particle board, cardboard, medium density fiberboard (MDF), hard fiberboard (also known as high density fiberboard or HDF), plywood, pellet blocks and boards composed of a composite of strands and plywood.

[0079] The independent and dependent claims set forth specific and preferred features of the present invention. The features in the dependent claims can be appropriately combined with the features of the independent claims or other dependent claims.

[0080] In conjunction with the accompanying drawings that describe the principles of the present invention, the above and other features, characteristics and advantages of the present invention will become apparent through the detailed description.

[0081] Examples

[0082] Compounds Applied:

[0083] -MDI 1: PB PM 4350 is a polymeric methylene diphenyl diisocyanate (pMDI) with a viscosity of 205 mPa.s at 25 °C and an NCO value of 30.9% NCO.

[0084] -MDI 2: PB PM 4358 is a polymeric methylene diphenyl diisocyanate (pMDI) with a viscosity of 675 mPa.s at 25 °C and an NCO value of 30.5% NCO.

[0085] -MDI 3: OSB EFC 4362 is a prepolymerized MDI with a viscosity of 395 mPa.s at 25 °C and an NCO value of 27.3% NCO.

[0086] -Natural oil 1: AP-60 (Cargill) is a natural oil (rapeseed oil) based on refined plant triglycerides, containing oleic, linoleic, and linolenic fatty acids. The typical viscosity of Natural oil 1 is less than 50 mPa.s at 25 °C.

[0087] -Fatty acid ester 1: AP-406 (Cargill) is a vegetable oil methyl ester product based on oleic, linoleic, and linolenic fatty acids derived from rapeseed oil. The typical viscosity of Fatty acid ester 1 is less than 30 mPa.s at 25 °C.

[0088] -Natural oil 2: Agri-Pure (Cargill) is a natural oil (soybean oil) based on refined plant triglycerides. The typical viscosity of Natural oil 2 is less than 50 mPa.s at 25 °C.

[0089] Unless otherwise specified, all parts and all percentages in the following examples and throughout the specification are by weight parts or weight percentages, respectively. As applied herein, the term "natural oil" refers to the weight percentage of triglyceride (TG)-based bio-oil compounds in the formulation, and the term "fatty acid ester" refers to the esterified fatty acid compounds in the required formulation.

[0090] Binder Formulation

[0091] The isocyanate compound (MDI), triglyceride (TG)-based oil compound (natural oil), and esterified fatty acid (EFA) compound are mixed together at room temperature using a low-power mixer (Heidolph). The triglyceride (TG)-based oil compound (natural oil) and esterified fatty acid (EFA) compound can be premixed or added separately. If added separately, the esterified fatty acid (EFA) compound needs to be added to the MDI first and then added to the natural oil.

[0092] The mixtures were stored at room temperature, and the appearance was observed, and the NCO and viscosity were measured. Table 1 lists the formulations with different weight ratios of different compounds. Resins 1, 2, and 3 are prior art reference formulations without bio-based compounds. Resins showing obvious separation (without stable formation) are not within the required formulation range and are not suitable for use as adhesives.

[0093] Oriented Strand Board (OSB) made with the binder formulation of the present invention (Table 2)

[0094] Resins 1, 2, 7, 9, and 15 were applied as adhesive formulations to prepare OSB panels. Finally, after cooling and conditioning at 23 °C and 50% relative humidity, the panels were cut into 5 x 5 cm 2 samples for further characterization.

[0095] The two layers of the face and the core were adhesively bonded separately. The MDI loading for both layers was 3%. Laying was done manually. First, the adhesively bonded surface material was evenly distributed in a preformed mat mold, then the adhesively bonded chips were laid on the surface layer as evenly as possible, and then the second surface layer material was evenly distributed on the core layer. The preformed mat was manually "pre-pressed" by applying a metal plate. The target density of the panel was 650 kg / m 3 . The mold was removed, and three panels were placed in a press ( press). The panels were pressed at a high temperature (220 °C) for a certain period of time (pressure factor).

[0096] Finally, after cooling and conditioning at 23 °C and 50% relative humidity, the panels were cut into 5 x 5 cm 2 samples for further characterization.

[0097] The thickness swelling rate was measured according to standard BS 317. The internal bond strength IB V20 (dry strength) and V100 (wet strength) were measured according to standard BS 319. All the values described in Table 2 are the average results of 8 cut samples.

[0098] Particle board prepared with the binder formulation of the present invention (Table 3)

[0099] Resins 1, 3, 15, and 27 were applied as adhesive formulations to prepare particleboards. The particleboard (PB) is a three-layer board, where the surface layer (2) consists of very fine particles (final moisture content (MC) of 10 wt%), and the core layer (1) consists of larger wood chips (final MC of 5 wt%).

[0100] The skin and core layers are adhesively bonded separately. The MDI loading of both layers is 3%. Laying is done manually. First, the adhesively bonded surface layer material is evenly distributed in a pre-formed mat mold, then the adhesively bonded chip is laid on the surface layer as evenly as possible, and then the second surface layer material is evenly distributed on the core layer. The pre-formed mat is manually "pre-pressed" by applying a metal plate. The target density of the panel is 650 kg / m 3 . The mold is removed and three panels are placed in a press ( press). The panels are pressed at a high temperature (220 °C) for a certain period of time (pressure factor).

[0101] Finally, after cooling and conditioning at 23 °C and 50% relative humidity, the panels are cut into 5x5 cm 2 samples for further characterization.

[0102] The thickness swelling rate is measured according to standard BS 317. The internal bond strength IB V20 (dry strength) is measured according to standard BS 319. The modulus of elasticity (MOE) and modulus of rupture (MOR) are measured according to BS 310, and the surface soundness is measured according to BS 311. All values described in Table 3 are the average results of 8 cut samples.

[0103]

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[0105]

Claims

1. A formulation comprising the following compounds: a) at least one isocyanate compound, and b) at least one bio-oil-based compound selected from triglyceride (TG)-based bio-oil compounds and esterified bio-based fatty acid compounds, and c) optionally, a catalyst compound for promoting urea / polyurethane formation, d) optionally, additional auxiliary compounds and / or additives, characterized in that the ratio of the TG-based bio-oil compound to the esterified fatty acid compound is from 60 / 40 to 0 / 100, preferably from 55 / 45 to 0 / 100, more preferably from 50 / 50 to 40 / 60, most preferably from 45 / 55 to 50 / 50, and based on 100 wt% of the total formulation, the amount of at least one isocyanate compound (a) is at least 90 wt%.

2. The formulation of claim 1, wherein the triglyceride (TG)-based bio-oil compound is selected from linseed oil, soybean oil, palm kernel oil, sunflower oil, corn oil, cottonseed oil, perilla oil, rapeseed oil, olive oil and / or canola oil, palm oil, coconut oil, rice bran oil, safflower oil, sesame oil, tall oil, and mixtures thereof.

3. The formulation of any one of the preceding claims, wherein the bio-based fatty acid for preparing the esterified fatty acid compound is selected from caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, myristoleic acid, palmitoleic acid, thujic acid, oleic acid, elaidic acid, isolenic acid, linoleic acid, elaidic linoleic acid, (α)-linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, docosahexaenoic acid, and mixtures thereof.

4. The formulation of any one of the preceding claims, wherein the esterified fatty acid compound is selected from a mixture of methyl esters of saturated and unsaturated C16-C22 fatty acids derived from rapeseed oil.

5. The formulation of any one of the preceding claims, wherein based on 100 wt% of the total formulation, the amount of at least one bio-oil-based compound selected from triglyceride (TG)-based bio-oil compounds and esterified bio-based fatty acid compounds in the formulation is at least 10 wt%, preferably at least 20 wt%, more preferably at least 25 wt%, and most preferably at least 30 wt%.

6. The formulation of any one of the preceding claims, wherein based on 100 wt% of the total formulation, the amount of at least one isocyanate compound is at least 80 wt%, preferably at least 75 wt%, and most preferably at least 70 wt%.

7. The formulation of any one of the preceding claims, wherein the at least one isocyanate compound is selected from: hexamethylene diisocyanate, meta- and para-phenylene diisocyanate, toluene-2,4- and toluene-2,6-diisocyanate, diphenylmethane diisocyanate in its 2,4', 2,2' and 4,4' isomeric forms and mixtures thereof, mixtures of diphenylmethane diisocyanate and its oligomers, meta-chlorobenzene-2,4-diisocyanate, naphthalene-1,5-diisocyanate, diphenyl-4,4'-diisocyanate, 4,4'-diisocyanate-3,3'-dimethyl-diphenyl, 3-methyl-diphenylmethane-4,4'-diisocyanate, diphenyl ether diisocyanate, cyclohexane-2,4- and -2,3-diisocyanate, 1-methylcyclohexyl-2,4- and -2,6-diisocyanate, bis-(isocyanatocyclohexyl)methane, 2,4,6-triisocyanatotoluene, 2,4,4-triisocyanatodiphenyl ether, isophorone diisocyanate, butene diisocyanate, trimethylhexamethylene diisocyanate, isocyanatomethyl-1,8-octane diisocyanate, tetramethyldi-xylene diisocyanate, 1,4-cyclohexane diisocyanate, tolylene diisocyanate and mixtures thereof.

8. The formulation of any one of the preceding claims, wherein the at least one isocyanate compound is selected from isocyanate-terminated prepolymers prepared by reacting an excess of diisocyanate or a higher functionality polyisocyanate with a hydroxyl-terminated polyester or a hydroxyl-terminated polyether, and the NCO content of the isocyanate-terminated prepolymer is 5 - 30 wt%, preferably 10 - 28 wt%, particularly preferably 15 - 25 wt%.

9. The formulation of any one of the preceding claims, wherein the catalyst compound used is selected from at least one polyurethane catalyst, preferably selected from aliphatic and aromatic tertiary amines such as N,N-dimethylcyclohexylamine, organometallic compounds, especially tin compounds such as stannous octoate and dibutyltin dilaurate, and alkali metal salts.

10. The formulation of any one of the preceding claims, wherein the formulation comprises at least one additive selected from the following: hardeners, surfactants, release agents, waxes and pigments.

11. A process for preparing the formulation of any one of the preceding claims, wherein compounds a) and b) and optionally c) and / or d) are mixed at room temperature by mixing, simple shaking or slow stirring.

12. Use of the formulation of any one of claims 1 - 10 as an adhesive.

13. The use according to claim 12, for bonding at least one lignocellulosic body.

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