Waterborne adhesive composition comprising a thermosetting resin with improved stability

Abstract

The present invention relates to an aqueous adhesive composition comprising a thermosetting resin based on: - at least one aromatic compound A1 comprising at least one aromatic ring bearing at least two functional groups, one of which is an aldehyde or a hydroxymethyl functional group, the other functional group being an aldehyde or a hydroxymethyl functional group; - at least one aromatic polyphenol A2 comprising at least one aromatic ring bearing at least two hydroxyl functional groups in meta position relative to each other, at least two ortho positions of at least one hydroxyl functional group being unsubstituted; and, - at least one organic compound G selected from a monosaccharide G1 or an oligosaccharide G2. This adhesive composition can be used in particular for assembling wooden elements.

Description

Technical Field

[0001] The field of the present invention relates to aqueous adhesive compositions intended for bonding elements, their uses and methods for manufacturing such compositions, methods for assembling elements using these compositions, and components manufactured using these compositions. Background Technology

[0002] Phenolic plastics, or "phenolic resins" (abbreviated PF), are derived from formaldehyde and phenol. Because phenol is a molecule with several reactive sites, it ultimately forms a three-dimensional network. Phenolic plastics are particularly used as adhesives, for example, in the manufacture of pressed wood or composites reinforced with glass fibers, fabric fibers, etc.

[0003] In the wood industry, US2360376 describes a phenolic composition. This composition comprises a phenolic resin based on formaldehyde and phenol. The molar ratio of formaldehyde to phenol is in the range of 2 to 3.5. This composition is used in a method of bonding plywood articles comprising several wood-based panels. In this method, one or more panels are coated with a layer of the composition, the panels are bonded together through the layer of the composition, and the bonded panels are cured under pressure. The resulting bonded assembly exhibits high cohesion due to the excellent adhesive properties of the composition.

[0004] However, the use of formaldehyde (or formalin) (and in excess of phenol) results in the release of formaldehyde not only during pressure curing but also during the storage and use of the bonded components. However, due to recent changes in regulations relating to this type of compound (particularly European regulations), there is a desire to limit or even eliminate the use of formaldehyde or formaldehyde precursors as much as possible.

[0005] In its application WO2017 / 168109, the applicant proposed an aqueous adhesive composition for bonding wood, which comprises a thermosetting resin based on phloroglucinol and 5-(hydroxymethyl)furfural, has improved adhesive properties and is formaldehyde-free.

[0006] However, this new system has a unique characteristic of high reactivity. This reactivity results in a significant increase in viscosity once the water-based adhesive composition is formulated. This very reactivity makes it difficult to use when applications require these water-based adhesive compositions to be applied for tens of minutes or even hours. In other words, the bonding of wooden components can be completed in a very short time. Summary of the Invention

[0007] The object of the present invention is to provide an aqueous adhesive composition comprising a thermosetting resin, having improved adhesive properties, being formaldehyde-free, and providing a smaller viscosity variation than the adhesive composition in document WO2017 / 168109.

[0008] During its research, the applicant discovered a water-based adhesive composition that does not use free formaldehyde and whose viscosity changes very little over time, which makes it possible to achieve the above objectives.

[0009] Therefore, one aspect of the present invention relates to an aqueous adhesive composition comprising a thermosetting resin based on:

[0010] - At least one aromatic compound A1, said aromatic compound A1 comprising at least one aromatic ring having at least two functional groups, one of which is an aldehyde functional group or a hydroxymethyl functional group, and the other functional groups are aldehyde functional groups or hydroxymethyl functional groups.

[0011] - At least one aromatic polyphenol A2, said aromatic polyphenol A2 comprising at least one aromatic ring, said aromatic ring having at least two hydroxyl functional groups at the meta position relative to each other, and the two ortho positions of the at least one hydroxyl functional group being unsubstituted; and

[0012] - At least one organic compound G, said organic compound G being selected from monosaccharide G1 or oligosaccharide G2.

[0013] Another subject of the invention relates to the use of the aqueous adhesive composition according to the invention for bonding at least two cellulose elements (advantageously at least two wooden elements).

[0014] The present invention also relates to a method for bonding two cellulose elements (advantageously two wooden elements), wherein:

[0015] - Applying a layer of the aqueous adhesive composition as defined above to at least one of the elements, and

[0016] - Components are joined together by layers of an aqueous adhesive composition.

[0017] The present invention also relates to an adhesive assembly for two elements, comprising a layer of an aqueous adhesive composition as defined above for bonding at least one of the elements to the other.

[0018] The invention and its advantages will be readily understood from the following description. Detailed Implementation

[0019] Formulation of I-waterborne adhesive compositions

[0020] In this specification, unless otherwise expressly stated, all percentages (%) shown are by weight.

[0021] "Opposition relative to each other" is understood to mean that the functional groups under discussion are opposite to each other, that is, at positions 1 and 4 of the 6-membered aromatic ring. Similarly, "opposition relative to a functional group" is the position on the 6-membered aromatic ring that is opposite to the functional group.

[0022] The term "adjacent to a functional group" refers to the position occupied by an aromatic ring carbon that is immediately adjacent to the aromatic ring carbon containing the functional group. Similarly, "adjacent" relative to a functional group is the position on an aromatic ring adjacent to the functional group.

[0023] The term "meta-position relative to a functional group" refers to the position occupied by an aromatic ring carbon separated from the aromatic ring carbon containing the functional group by a single other carbon in the aromatic ring. Similarly, "meta-position relative to a functional group" is the position adjacent to the "ortho-functional group" on the aromatic ring containing that functional group.

[0024] "Meta relative to each other" is understood to mean that the functional group in question (e.g., the hydroxyl functional group in aromatic polyphenols) is carried by an aromatic ring carbon, which is separated from each other by a single other carbon in the aromatic ring.

[0025] The term "member" of a ring refers to the constituent atoms of the ring skeleton. Thus, for example, a benzene ring contains six members, each consisting of a carbon atom. In another example, a furan ring contains five members: four members each consisting of a carbon atom, and the remaining member consisting of an oxygen atom.

[0026] “CHO” represents the aldehyde functional group.

[0027] "CH2OH" represents the hydroxymethyl functional group.

[0028] In the context of this invention, "compound A1" means an aromatic compound as defined in Section I.1.

[0029] In the context of this invention, "compound A2" means the aromatic polyphenol-based compound defined in Section I.2.

[0030] In the context of this invention, "compound G" means an organic compound G selected from monosaccharide G1 or oligosaccharide G2 as defined in Section I.3.

[0031] In the context of this invention, "compound A3" means a compound based on aromatic hydrocarbons as defined in Section I.4.

[0032] The term "aromatic polyphenols" refers to aromatic compounds that contain at least one benzene ring with more than one hydroxyl functional group.

[0033] Within the context of this invention, the carbon products mentioned in the specification may be of fossil or bio-based origin. In the case of bio-based origin, they may be produced in whole or in part from biomass or obtained from renewable raw materials derived from biomass.

[0034] In the context of this invention, it may also be conceived that the carbonaceous products mentioned in the specification contain isotopes of certain chemical elements.

[0035] Furthermore, any numerical interval expressed as "between a and b" represents a range of values ​​from greater than a to less than b (i.e., excluding the endpoints a and b), while any numerical interval expressed as "from a to b" means a range of values ​​from a to b (i.e., including the strict endpoints a and b).

[0036] The statement “composition based” should be understood to mean that the composition comprises a mixture of the various basic components and / or reaction products used in the composition, fabric material or composite or finished product containing such composite, and that some of the basic components are intended or able to react with each other or with the surrounding chemicals in particular during the curing step.

[0037] Therefore, the aqueous adhesive composition according to the first embodiment of the present invention comprises at least one (i.e., one or more) thermosetting resin according to the present invention, which is itself based on at least one (i.e., one or more) aromatic compounds, at least one (i.e., one or more) aromatic polyphenols and based on at least one organic compound G selected from monosaccharide G1 or oligosaccharide G2, these components will be described in detail below.

[0038] I.1-Aromatic compound A1

[0039] The first essential component of the thermosetting resin according to a first embodiment of the present invention is an aromatic compound comprising at least one aromatic ring having at least two functional groups, one of which is an aldehyde functional group or a hydroxymethyl functional group, and the other functional groups are aldehyde functional groups or hydroxymethyl functional groups. Therefore, according to the present invention, the aromatic ring has a hydroxymethyl functional group, or a hydroxymethyl functional group and an aldehyde functional group. Therefore, the compound according to the present invention corresponds to general formula (I):

[0040] B-Ar-C(I)

[0041] Ar represents an aromatic ring, and B and C represent CHO or CH2OH, respectively.

[0042] The aromatic ring is advantageously a 5-membered or 6-membered ring, comprising a carbon atom as a member and optionally one or more heteroatoms, particularly nitrogen, oxygen, or sulfur atoms, optionally oxidized in the form of N-oxide or S-oxide. In an alternative form, the aromatic ring contains 0, 1, or 2 heteroatoms. The remainder of the aromatic ring may be substituted or unsubstituted.

[0043] The aromatic ring may have 0, 1 or 2 aldehyde functional groups, with 0 or 1 aldehyde functional group being advantageous.

[0044] The aromatic ring may have 1, 2 or 3 hydroxymethyl functional groups, and preferably 1 or 2 hydroxymethyl functional groups.

[0045] In addition, the aromatic ring can also have 0, 1 or 2 other functional groups, especially hydroxyl functional groups.

[0046] In embodiments where the aromatic ring is a 6-membered ring, B and the hydroxymethyl functional group are advantageously located in the meta or para position relative to each other.

[0047] In embodiments where the aromatic ring is a 5-membered ring, the ring may contain one or more heteroatoms, particularly nitrogen, oxygen, or sulfur atoms, optionally oxidized in the form of N-oxides or S-oxides. Advantageously, the aromatic ring contains one or two heteroatoms, preferably one heteroatom.

[0048] In this embodiment where the aromatic ring is a 5-membered ring, at least one of the following three conditions is met:

[0049] - The aromatic ring contains 0 or only one aldehyde functional group;

[0050] -The aromatic ring contains one or two hydroxymethyl functional groups;

[0051] - The aromatic ring contains one or two aldehyde functional groups.

[0052] Advantageously, apart from the aldehyde and hydroxymethyl functional groups, the rest of the aromatic ring is unsubstituted.

[0053] Advantageously, in the first case, the aromatic ring comprises:

[0054] - A single aldehyde functional group;

[0055] - A single hydroxymethyl functional group;

[0056] - Apart from the aldehyde and hydroxymethyl functional groups, the rest of the aromatic ring is unsubstituted.

[0057] Advantageously, in the second case, the aromatic ring comprises:

[0058] - Two hydroxymethyl functional groups;

[0059] - Apart from the hydroxymethyl functional group, the rest of the aromatic ring is unsubstituted.

[0060] Advantageously, in the third case, the aromatic ring comprises:

[0061] - Two aldehyde functional groups;

[0062] - Apart from the aldehyde functional group, the rest of the aromatic ring is unsubstituted.

[0063] Advantageously, aromatic compound A1 corresponds to general formula (II):

[0064]

[0065] Wherein, B and C represent CHO or CH2OH respectively, X represents O, NR1, NO, S, SO, SO2 or SR2R3, and R1, R2 and R3 each independently represent hydrogen or alkyl, aryl, arylalkyl, alkylaryl or cycloalkyl groups.

[0066] In the first alternative form, compound A1 has the general formula (II'):

[0067]

[0068] X and B are as defined above.

[0069] In a particularly advantageous embodiment, B represents CHO. In another embodiment, B represents CH2OH.

[0070] According to the preferred embodiment, X represents O.

[0071] In this embodiment, compound A1 has formula (IIa):

[0072]

[0073] B is as specified above.

[0074] And more specifically, it has formula (II'a1) or (II'a2):

[0075]

[0076] 5-(hydroxymethyl)furfural (II'a1) is a particularly suitable aldehyde because this organic compound can be readily derived from renewable resources. Specifically, it is particularly derived from the dehydration of certain sugars (e.g., fructose, glucose, sucrose, cellulose, and inulin).

[0077] In the second alternative form, compound A1 has the general formula (II”):

[0078]

[0079] B is as specified above.

[0080] And more specifically, it has formula (II”a1) or (II”a2):

[0081]

[0082] In another embodiment, X represents NR1 or NO, advantageously representing NR1. R1 is defined as above.

[0083] In its alternative form, compound A1 has formula (IIb):

[0084]

[0085] B is as specified above.

[0086] And more specifically, it has formula (II'b1) or (II'b2):

[0087]

[0088] R1 represents hydrogen, or an alkyl, aryl, arylalkyl, alkylaryl, or cycloalkyl group. Advantageously, R1 represents hydrogen or a C1-C6 alkyl group.

[0089] In another implementation, X represents S, SO, SO2, or SR2R3.

[0090] In this embodiment, compound A1 has the formula (IIc):

[0091] B is as specified above.

[0092]

[0093] Where X represents S, SR2R3, SO or SO2, R2 and R3 each independently represent hydrogen, or alkyl, aryl, arylalkyl, alkylaryl or cycloalkyl groups, and B is as defined above;

[0094] And more specifically, it has formula (II'c1) or (II'c2):

[0095]

[0096] Where X represents S, SR2R3, SO or SO2, and R2 and R3 each independently represent hydrogen, or alkyl, aryl, arylalkyl, alkylaryl or cycloalkyl groups.

[0097] Therefore, compound A1 can be:

[0098]

[0099] Advantageously, R2 and R3 each independently represent C1-C6 alkyl groups.

[0100] Compound A1 advantageously has the formula (II'c1) or (II'c2).

[0101] In another alternative form, the aromatic ring is a 6-membered ring that may contain 0, one, or several heteroatoms, particularly nitrogen heteroatoms, optionally oxidized in the form of N-oxides. In another alternative form, the aromatic ring contains 0, 1, or 2 heteroatoms.

[0102] B and the hydroxymethyl functional group are advantageously located in the meta or para position relative to each other.

[0103] The aromatic ring may have 0, 1 or 2 aldehyde functional groups, with 0 or 1 aldehyde functional group being advantageous.

[0104] The aromatic ring may have 1, 2 or 3 hydroxymethyl functional groups, and preferably 1 or 2 hydroxymethyl functional groups.

[0105] Advantageously, compound A1 has the general formula (III):

[0106]

[0107] Wherein D represents hydrogen, or an alkyl, aryl, arylalkyl, alkylaryl, or cycloalkyl, or hydroxyalkyl group. According to the present invention, p+n>1 and m<5.

[0108] Advantageously, the value of m is either 0 or 1.

[0109] Advantageously, D represents hydrogen or a hydroxymethyl group.

[0110] In an alternative form, n has a value of 1 and p has a value of 1.

[0111] In another alternative form, n has a value of 3 and p has a value of 0.

[0112] In another alternative form, n has a value of 2 and p has a value of 1.

[0113] In another alternative form, n has a value of 1 and p has a value of 2.

[0114] In another alternative form, n has a value of 0 and p has a value of 2.

[0115] In another alternative form, n has a value of 0 and p has a value of 3.

[0116] Preferably, the aromatic ring of aromatic compound A1 is a benzene ring. More preferably, the aldehyde is selected from 2-(hydroxymethyl)benzyl-1-carboxaldehyde, 3-(hydroxymethyl)benzyl-1-carboxaldehyde, 4-(hydroxymethyl)benzyl-1-carboxaldehyde, 1,2-(hydroxymethyl)benzene, 1,3-(hydroxymethyl)benzene, 1,4-(hydroxymethyl)benzene, 2-methoxybenzaldehyde, 3-methoxybenzaldehyde, 4-methoxybenzaldehyde, 2,6-dimethoxybenzaldehyde, 2,4,6-trimethoxybenzaldehyde, and mixtures of these compounds.

[0117] More preferably, the aromatic compound A1 used is 1-hydroxymethylbenzene-4-carboxaldehyde of formula (IIIa), 1,4-hydroxymethylbenzene of formula (IIIb), or terephthalic acid of formula (III'b):

[0118]

[0119] Preferably, when the thermosetting resin is based on polyphenols and one or more compounds of formula (I), the composition is formaldehyde-free.

[0120] When the thermosetting resin is based on polyphenols, one or more compounds of formula (I), and aldehydes, each aldehyde is preferably different from formaldehyde. The composition is then also formaldehyde-free.

[0121] In other words, and preferably, when an aldehyde is present, the aldehyde in the thermosetting resin, or each aldehyde, is different from formaldehyde.

[0122] Formaldehyde-free means that, by weight of total aldehydes, the formaldehyde content is less than or equal to 10%, preferably less than or equal to 5%, more preferably less than or equal to 2%, these percentages correspond to trace amounts that may be present in industrially used aldehydes.

[0123] I. 2-Aromatic polyphenols and / or aromatic monophenols-compound A2

[0124] According to a first embodiment of the invention, the second essential component of the thermosetting resin is an aromatic polyphenol A2 comprising one or more aromatic rings. The aromatic polyphenol comprises at least one aromatic ring having at least two hydroxyl functional groups at the meta position relative to each other, wherein the two ortho positions of the at least one hydroxyl functional group are unsubstituted.

[0125] According to one embodiment of the present invention, compound A2 may be a simple aromatic polyphenol molecule comprising one or more aromatic rings, at least one or even each of these aromatic rings having at least two hydroxyl functional groups at the meta position relative to each other, wherein the two adjacent positions of at least one hydroxyl functional group are unsubstituted.

[0126] According to another embodiment of the present invention, compound A2 may be a precondensation resin based on the following substances:

[0127] - At least one aromatic polyphenol comprising at least one aromatic ring having at least two hydroxyl functional groups at the meta position relative to each other, wherein the two ortho positions of the at least one hydroxyl functional group are unsubstituted; and

[0128] - At least one compound capable of reacting with the aromatic polyphenol and containing at least one aldehyde functional group, and / or at least one compound capable of reacting with the aromatic polyphenol and containing at least two hydroxymethyl functional groups attached to an aromatic ring.

[0129] This precondensation resin based on aromatic polyphenols conforms to the definition of compound A2 and, unlike the simple molecules described above, contains repeating units. Where appropriate, the repeating unit contains at least one aromatic ring with at least two hydroxyl functional groups at the meta position relative to each other.

[0130] In the following specific embodiments, the aromatic rings of aromatic polyphenols and / or aromatic monophenols are described. For clarity, "aromatic polyphenols" and / or "aromatic monophenols" are described herein in their simple molecular form. The aromatic polyphenol and / or aromatic monophenol can subsequently be condensed, and partially defines the repeating unit. The characteristics of the precondensed resin are then described in more detail.

[0131] Aromatic polyphenols A2

[0132] In a preferred embodiment, the aromatic ring of the aromatic polyphenol has three hydroxyl functional groups at the meta position relative to each other.

[0133] Preferably, the two adjacent positions of each hydroxyl functional group are unsubstituted. This should be understood to mean that the two carbon atoms flanking (in their adjacent positions) of the hydroxylated carbon atom (i.e., the carbon atom with the hydroxyl functional group) have simple hydrogen atoms.

[0134] More preferably, the remainder of the aromatic ring is unsubstituted. This should be understood to mean that the other carbon atoms in the remainder of the aromatic ring (other than those with hydroxyl functional groups) have simple hydrogen atoms.

[0135] In one embodiment, the aromatic polyphenol comprises several aromatic rings, at least two of which each have at least two hydroxyl functional groups at the meta position relative to each other, and the two ortho positions of at least one hydroxyl functional group in at least one aromatic ring are unsubstituted.

[0136] In a preferred embodiment, at least one aromatic ring of the aromatic polyphenol has three hydroxyl functional groups at the meta position relative to each other.

[0137] Preferably, at least two adjacent positions of each hydroxyl functional group of at least one aromatic ring are unsubstituted.

[0138] Even better, the two adjacent positions of each hydroxyl functional group in each aromatic ring are unsubstituted.

[0139] More preferably, the remainder of each aromatic ring is unsubstituted. This should be understood to mean that the other carbon atoms in the remainder of each aromatic ring (other than those with hydroxyl functional groups or groups that link the aromatic rings together) have simple hydrogen atoms.

[0140] Advantageously, an aromatic ring having at least two hydroxyl functional groups at the meta position relative to each other (with at least two ortho positions of at least one hydroxyl functional group being unsubstituted) is a benzene ring.

[0141] Advantageously, each aromatic ring of an aromatic polyphenol is a benzene ring.

[0142] As examples of aromatic polyphenols containing only one aromatic ring, resorcinol and phloroglucinol can be specifically mentioned, as hints, they have structural formulas (IV) and (V), respectively:

[0143]

[0144] For example, in the case of aromatic polyphenols containing several aromatic rings, at least two of these aromatic rings are the same or different, selected from those having the following general formula:

[0145]

[0146] Wherein, if there are multiple identical or different symbols Z1 and Z2 on the same aromatic ring, the symbols Z1 and Z2 represent atoms (e.g., carbon, sulfur, or oxygen) or linking groups, which by definition are at least divalent and link at least these two aromatic rings to the remainder of the aromatic polyphenol.

[0147] Another example of aromatic polyphenols is 2,2',4,4'-tetrahydroxydiphenyl sulfide having the following structural formula (VII):

[0148]

[0149] Another example of aromatic polyphenols is 2,2',4,4'-tetrahydroxybenzophenone, which has the following structural formula (VIII):

[0150]

[0151] Note that each compound VII and VIII is an aromatic polyphenol comprising two aromatic rings (which have the formula VI-c), wherein each aromatic ring has at least two (in this case, two) hydroxyl functional groups at the meta position relative to each other.

[0152] Note that in the case of aromatic polyphenols containing at least one aromatic ring according to formula VI-b, the two ortho positions of each hydroxyl functional group of at least one aromatic ring are unsubstituted. In the case of aromatic polyphenols containing several aromatic rings according to formula VI-b, the two ortho positions of each hydroxyl functional group of each aromatic ring are unsubstituted.

[0153] According to one embodiment of the invention, the aromatic polyphenol is selected from resorcinol (IV), phloroglucinol (V), 2,2',4,4'-tetrahydroxydiphenyl sulfide (VII), 2,2',4,4'-tetrahydroxybenzophenone (VIII), and mixtures of these compounds. In a particularly advantageous embodiment, the aromatic polyphenol is phloroglucinol.

[0154] In one embodiment, compound A2 comprises a precondensation resin based on aromatic polyphenols as described in any of these embodiments.

[0155] This precondensation resin is advantageously based on:

[0156] - At least one aromatic polyphenol as defined above, preferably selected from resorcinol (IV), phloroglucinol (V), 2,2',4,4'-tetrahydroxydiphenyl sulfide (VII), 2,2',4,4'-tetrahydroxybenzophenone (VIII), and mixtures thereof; and

[0157] - At least one compound capable of reacting with the aromatic polyphenol and containing at least one aldehyde functional group, and / or at least one compound capable of reacting with the aromatic polyphenol and containing at least two hydroxymethyl functional groups attached to an aromatic ring.

[0158] Compounds capable of reacting with the aromatic polyphenols may be: aromatic compounds as defined above in Section I.1, compounds having the formula Ar-(CHO)2 (where Ar is as defined above for aromatic compounds in Section I.1), or any other aldehyde. Advantageously, the compounds are selected from: aromatic compounds comprising an aromatic ring having at least two functional groups (one of which is a hydroxymethyl functional group and the other is an aldehyde functional group or a hydroxymethyl functional group), formaldehyde, furfural, 2,5-furandicarboxaldehyde, 1,4-benzenedialdehyde, 1,3-benzenedialdehyde, 1,2-benzenedialdehyde, and mixtures thereof. Very advantageously, when the compound is an aromatic compound comprising an aromatic ring having at least two functional groups (one of which is a hydroxymethyl functional group and the other is an aldehyde functional group or a hydroxymethyl functional group), the compound is selected from 5-(hydroxymethyl)furfural, 2,5-di(hydroxymethyl)furan, and mixtures thereof.

[0159] Therefore, in the precondensation resin based on aromatic polyphenols, the repeating unit corresponds to the characteristics of the aromatic polyphenols as defined above, wherein at least one unsubstituted carbon atom of the aromatic ring is attached to another unit.

[0160] Regardless of what compounds other than aromatic polyphenols (which are the basis of the precondensation resin) are, the precondensation resin does not contain free formaldehyde. This is because, even in the case where the precondensation resin is based on aromatic polyphenols and formaldehyde as described above, since the formaldehyde has already reacted with the aromatic polyphenols, the precondensation resin does not contain free formaldehyde that is readily capable of reacting with compound A1 according to the invention in subsequent steps.

[0161] Compound A2 may also comprise a mixture of free aromatic polyphenol molecules as described above and an aromatic polyphenol-based precondensation resin. In particular, compound A2 may also comprise a mixture of phloroglucinol and a phloroglucinol-based precondensation resin.

[0162] I.3-Compound I.3-Organic Compound G

[0163] According to a first embodiment of the present invention, the third essential component of the thermosetting resin is an organic compound G selected from monosaccharide G1 or oligosaccharide G2.

[0164] Advantageously, the organic compound G is a sugar. As is known to those skilled in the art, sugar is understood to mean a monosaccharide or oligosaccharide derivative in cyclic or open-chain form.

[0165] Oligosaccharides are understood to be oligomers formed by 2 to 10 monosaccharides through α or β glycosidic bonds.

[0166] Advantageously, the organic compound G is selected from the open-chain form of the monosaccharide G1.

[0167] Preferably, the monosaccharide G1 is selected from fructose, glucose, xylose, erythrose, and mixtures of these compounds.

[0168] Advantageously, oligosaccharide G2 is selected from oligosaccharides of sucrose, glucose, and fructose, as well as mixtures of these compounds.

[0169] I. 4-Aromatic compound A3 or phenol optionally substituted with a single alkyl group.

[0170] Advantageously, in a second embodiment of the invention, the aqueous adhesive composition further comprises: a phenol optionally substituted with a single alkyl group or a single alkenyl group, and / or at least one aromatic compound A3 comprising at least two aromatic rings with a single hydroxyl functional group, and it should be understood that at least one of the ortho or para positions of each aromatic ring is unsubstituted.

[0171] In this second embodiment of the invention, the fourth essential component of the thermosetting resin is a phenol optionally substituted with a single alkyl group or a single alkenyl group, and / or at least one aromatic compound A3. Aromatic compound A3 comprises at least two aromatic rings with a single hydroxyl functional group, and it should be understood that at least one of the ortho or para positions of each aromatic ring is unsubstituted.

[0172] Phenols optionally substituted with a single alkyl group or a single alkenyl group

[0173] Advantageously, the phenol optionally substituted with a single alkyl group is selected from phenol, o-cresol, m-cresol, p-cresol, or mixtures of these compounds.

[0174] Advantageously, phenols substituted with a single alkenyl group are coumarol of the following formula.

[0175]

[0176] Aromatic compound A3

[0177] In a preferred embodiment, the aromatic compound A3 corresponds to the general formula (X):

[0178]

[0179] Where Y1 represents an alkyl, aryl, arylalkyl, alkylaryl, cycloalkyl, or alkenyl group, which are substituted, and Y2 and Y3 are the same or different and represent H or an ether group.

[0180] Advantageously, Y2 and Y3 are ortho to the hydroxyl functional group and represent H or OY4, wherein Y4 represents an alkyl, aryl, arylalkyl, alkylaryl, cycloalkyl or alkenyl group, preferably CH3.

[0181] More preferably, the aromatic compound A3 comprises at least two aromatic rings with a single hydroxyl functional group, and it should be understood that one of the adjacent positions of each aromatic ring with a single hydroxyl functional group is unsubstituted.

[0182] Advantageously, the aromatic compound A3 is selected from bisphenol-A, lignin, or mixtures of these compounds.

[0183] I.5 - Preparation of Additive-Waterborne Adhesive Composition

[0184] The aqueous adhesive compositions according to the first and second embodiments of the present invention may, of course, contain all or some of the additives commonly used in aqueous adhesive compositions, such as those used in conventional phenolic plastic adhesives; for example, reference will be made to alkalis (such as ammonia, sodium hydroxide, potassium hydroxide, or ammonium hydroxide), dyes, fillers (such as carbon black or silica, chalk, olive oil, or any other natural filler), antioxidants or other stabilizers, and thickeners (such as carboxymethyl cellulose) or gelling agents (such as gelatin) (which enable the increase of the viscosity of the composition). Reference will also be made to additives that enable the modification of the resin's set time or gel time and open time. As those skilled in the art know, set time or gel time is the length of time during which the resin can be applied to its substrate, while open time is the length of time after the resin has been applied to its substrate that the resin can be kept in the open without adversely affecting the quality of subsequent bonding with a complementary substrate. The set time or gel time and open time depend particularly on temperature, pressure, or resin concentration.

[0185] Typically, during the preparation of the resin, the components of the thermosetting resin itself are mixed without a predetermined order. However, according to a first embodiment of the invention, it is advantageous to first mix water with sodium hydroxide, then with organic compound G, then with aromatic polyphenol A2, and then with aromatic compound A1. Alternatively, according to a first embodiment of the invention, it is advantageous to first mix water with sodium hydroxide, then with a phenol optionally substituted with a single alkyl group, and / or at least one aromatic compound A3, then with aromatic polyphenol A2, and then with aromatic compound A1.

[0186] The production of thermosetting resins can be carried out at a pH between 9 and 14, more preferably between 10 and 12.

[0187] Therefore, the thermosetting resin according to the first embodiment is obtained by mixing the following substances in an alkaline solvent:

[0188] -Aromatic compound A1,

[0189] -Aromatic polyphenols A2; and

[0190] - Organic compound G, wherein the organic compound G is selected from monosaccharide G1 or oligosaccharide G2;

[0191] The alkaline solvent preferably has a pH between 9 and 14, more preferably between 10 and 12.

[0192] Therefore, the thermosetting resin according to the second embodiment is obtained by mixing the following substances in an alkaline solvent:

[0193] -Aromatic compound A1,

[0194] -Aromatic polyphenols A2;

[0195] - Organic compound G, wherein organic compound G is selected from monosaccharide G1 or oligosaccharide G2; and

[0196] - Phenolic and / or aromatic compounds A3 that may be substituted with a single alkyl group or a single alkenyl group;

[0197] The alkaline solvent preferably has a pH between 9 and 14, more preferably between 10 and 12.

[0198] In some cases, such as at relatively high concentrations, those skilled in the art can find reasons to add thickeners (e.g., carboxymethyl cellulose) or gelling agents to limit the sedimentation of aromatic polyphenol A2.

[0199] In this embodiment, an amount of aromatic polyphenol A2 in molar quantity n2 and aromatic compound A1 in molar quantity n1 are mixed such that 0.3 ≤ (n2*N2) / (n1*N1) ≤ 3, preferably 0.5 < (n2*N2) / (n1*N1) ≤ 2.

[0200] The amount of organic compound G, of the monosaccharide G1 type (e.g., ketose (C6 fructose) or aldose (C4 erythrose, C5 xylose, C6 glucose)) or oligosaccharide G2 (e.g., sucrose) according to the reactivity desired by those skilled in the art, is adjusted. Typically, the weight ratio of compound G to polyphenol A2 is between 1% and 99% of aromatic compound A1, preferably between 30% and 90%, more preferably between 40% and 80%, and even more preferably between 50% and 70%.

[0201] The amount of the phenol or at least one aromatic compound A3, optionally substituted with a single alkyl group, according to the second embodiment of the invention is adjusted according to the target viscosity desired by those skilled in the art. Typically, the weight ratio of the phenol or at least one aromatic compound A3, optionally substituted with a single alkyl group, to the monophenol A2 is between 1% and 99% of the aromatic compound A1, preferably between 20% and 80%, more preferably between 30% and 70%, and even more preferably between 40% and 60%.

[0202] The concentration of the composition can be adjusted according to its specific application (open time, viscosity).

[0203] Advantageously, in the final adhesive composition thus prepared, the solid content of the thermosetting resin according to the invention ranges from 5% to 80% by weight, more preferably from 10% to 60% by weight, of the solids of the adhesive composition.

[0204] In cases where a higher viscosity is required for the final application of the adhesive composition, those skilled in the art can adjust the final viscosity characteristics of the adhesive composition by adding a thickener or any type of known filler (e.g., olive pit powder and / or chalk).

[0205] The composition can be used immediately or stored at ambient temperature (23°C) for a curing time, typically ranging from one to several hours or even several days, prior to final use. Those skilled in the art will determine the possible storage time based on the concentration of the composition.

[0206] Preferably, the water content of the aqueous adhesive composition ranges from 20% to 95% by weight, and more preferably from 40% to 90% by weight.

[0207] "Total solids content of the adhesive composition" is intended to refer to the ratio of the weight of the residue obtained after the adhesive composition has dried to the weight of the adhesive composition before drying.

[0208] "The solids content of the thermosetting resin" refers to the ratio of the weight of the thermosetting resin obtained after the adhesive composition has dried to the weight of the adhesive composition before drying.

[0209] The contents of these two solids were measured according to standard NF EN 827 (March 2006).

[0210] "Water content of an aqueous adhesive composition" is intended to refer to the weight of water as a percentage of the total weight of the adhesive composition.

[0211] II - Adhesive components of the present invention

[0212] II.1 - Definitions, Examples

[0213] As described above, the present invention also relates to the use of the above-described aqueous adhesive composition for bonding at least two cellulose elements (advantageously at least two wooden elements).

[0214] Therefore, the adhesive assembly of the two elements according to the invention comprises a layer of the aqueous adhesive composition as described above, which joins the two elements together.

[0215] In one implementation, both components are made of wood.

[0216] Wood is intended to refer to plant tissue produced by woody plants. Examples of plant tissue are tree trunks, branches, and roots. For example, woody plants that produce plant tissue include oak, chestnut, ash, walnut, beech, poplar, fir, pine, olive, alder, or birch.

[0217] Adhesives can also be used to bond components made of materials other than wood, such as plastic materials (e.g., thermosetting or thermoplastic materials), fabrics, mineral materials, or mixtures of these materials (including wood).

[0218] The term "component" is intended to refer to any integral piece or particle. Examples of wooden components are plywood pieces intended to form plywood assemblies, slats intended to form slatted assemblies, particles (such as chips, sawdust, powder, or flakes, whether or not the particles are oriented) used to form particleboard assemblies, fibers intended to form fiber assemblies (such as high-density fiberboard or medium-density fiberboard), and solid wood pieces (also known as logs) intended to form assemblies (such as furniture or frames).

[0219] Advantageously, the wooden components can be thin wood sheets, wood strips, wood fibers, wood particles, or mixtures of these compounds.

[0220] II.2 - Manufacturing of Adhesive Components

[0221] The adhesive assembly of the present invention can be prepared according to a method for bonding at least two cellulose elements (advantageously at least two wood elements), wherein:

[0222] - Applying a layer of the aqueous adhesive composition according to the invention to at least one of the elements, and

[0223] - Components are joined together by layers of an aqueous adhesive composition.

[0224] The step of applying the adhesive composition to one of the elements or the element can be carried out by any suitable method, especially by any known coating technique such as spraying, dipping, pressure injection or a combination of one or more of these techniques.

[0225] For example, for veneer wood chips, a content range of 50g.m is preferred. -2Up to 400g.m -2 70g.m -2 Up to 300g.m -2 Aqueous adhesive compositions. Those skilled in the art are able to adjust the weight of the aqueous adhesive composition per unit area to suit their wooden components and their own processes.

[0226] Following the application of the adhesive composition, a curing step is performed: depending on the target application, the bonded assembly is heated at a temperature ranging from 30°C to 250°C, preferably 50°C to 200°C, and most preferably 80°C to 160°C. The purpose of this heat treatment is to eliminate any solvents or water and to crosslink the thermosetting resin. Depending on the application, the heat treatment may be performed in two stages: the first heat treatment aims to eliminate any solvents or water, and the second heat treatment aims to complete the crosslinking of the thermosetting resin.

[0227] In the first embodiment, the elements bonded by the adhesive composition are subjected to a steam curing step, advantageously at a temperature of 100°C or higher.

[0228] In the second embodiment, the elements bonded by the adhesive composition are advantageously subjected to a curing step at a temperature of 80°C or higher by contact with the pressure plate of a curing press.

[0229] In the third embodiment, the elements bonded by the adhesive composition are subjected to a high-frequency curing step, advantageously in the range of 300 GHz to 300 MHz.

[0230] Preferably, the bonded assembly is held under pressure, for example, up to 18 kg·cm. -2 More preferably, the step of maintaining pressure is performed simultaneously with the heating step.

[0231] Depending on the circumstances, the duration of the heating and / or pressure holding steps can vary from minutes to hours, especially depending on the temperature / pressure pair used.

[0232] In one implementation, the two components to be assembled are made of wood.

[0233] Those skilled in the art know how to appropriately adjust the temperature and duration of the above heat treatment according to the specific implementation conditions of the invention, particularly based on the exact properties of the components. In particular, those skilled in the art have the advantage of observing the treatment temperature and time, as well as the weight of the aqueous adhesive composition per unit area, thereby finding, through successive approximations, the operating conditions for obtaining optimal adhesion and viscosity results for each specific embodiment of the invention.

[0234] III. Exemplary embodiments of the present invention and comparative tests

[0235] These tests show that the bonding performance of two wooden components using the aqueous adhesive composition according to the invention is equivalent to that of conventional formaldehyde-free adhesive compositions, and the reactivity (i.e., viscosity change at 20°C) of the aqueous adhesive composition according to the invention is lower.

[0236] To this end, thirteen aqueous adhesive compositions were prepared, seven according to the first embodiment of the invention (hereinafter referred to as C-2 to C-8), five according to the second embodiment of the invention (hereinafter referred to as F-1 to F-3, G-1 and S-1), and one not according to the invention (control composition, hereinafter referred to as C-1). Their formulations (expressed as weight percentages) are shown in Tables 1 and 2 below. The amounts listed in the tables are the amounts of the components in the dry state based on a total of 100 parts by weight of the aqueous adhesive composition (i.e., the components and water).

[0237] Adhesive composition C-1 is a control composition based on 5-(hydroxymethyl)furfural and phloroglucinol.

[0238] Adhesive compositions C-2 and C-7 are aqueous adhesive compositions based on 5-(hydroxymethyl)furfural, phloroglucinol and fructose according to a first embodiment of the present invention.

[0239] Adhesive composition C-3 is an aqueous adhesive composition based on 5-(hydroxymethyl)furfural, phloroglucinol and glucose according to a first embodiment of the present invention.

[0240] The adhesive composition C-4 is an aqueous adhesive composition based on 5-(hydroxymethyl)furfural, phloroglucinol and xylose according to a first embodiment of the present invention.

[0241] The adhesive composition C-5 is an aqueous adhesive composition based on 5-(hydroxymethyl)furfural, phloroglucinol and erythrose according to a first embodiment of the present invention.

[0242] Adhesive compositions C-6 and C-8 are aqueous adhesive compositions based on 5-(hydroxymethyl)furfural, phloroglucinol and sucrose according to a first embodiment of the present invention.

[0243] The adhesive composition F-1 is an aqueous adhesive composition based on 5-(hydroxymethyl)furfural, phloroglucinol, fructose and phenol according to a second embodiment of the present invention.

[0244] The adhesive composition F-2 is an aqueous adhesive composition based on 5-(hydroxymethyl)furfural, phloroglucinol, fructose and bisphenol-A according to a second embodiment of the present invention.

[0245] The adhesive composition F-3 is an aqueous adhesive composition based on 5-(hydroxymethyl)furfural, phloroglucinol, fructose and sodium lignin sulfonate according to a second embodiment of the present invention.

[0246] The adhesive composition G-1 is an aqueous adhesive composition based on 5-(hydroxymethyl)furfural, phloroglucinol, glucose and sodium lignin sulfonate according to a second embodiment of the present invention.

[0247] The adhesive composition S-1 is an aqueous adhesive composition based on 5-(hydroxymethyl)furfural, phloroglucinol, sucrose and sodium lignin sulfonate according to a second embodiment of the present invention.

[0248] Scheme for producing water-based adhesive compositions

[0249] Organic compound G, followed by aromatic compound A1 (e.g., 5-(hydroxymethyl)furfural) and sodium hydroxide, are introduced into a 250 ml round-bottom flask equipped with a mechanical stirring system. The mixture is stirred for 1 min to 60 min to homogenize it (e.g., at 250 rpm). Next, compound A2 (e.g., phloroglucinol) is added, and the mixture is stirred for, for example, 1 min to 60 min to homogenize it (e.g., at 250 rpm). This yields mixture 1 of the aqueous adhesive composition according to the first embodiment. To obtain mixture 2 of the aqueous adhesive composition according to the second embodiment, a phenol or at least one aromatic compound A3 (e.g., phenol and / or bisphenol A and / or sodium lignin sulfonate) optionally substituted with a single or unsubstituted alkyl group is then added. The mixture 1 or 2 thus formed is stirred for 1 min to 60 min at a temperature ranging from 20°C to 90°C. The previously described technical filler is added to the composition. Depending on the components added (which those skilled in the art know how to determine), stirring is carried out at ambient temperature for 5 min to 15 min. At the end of this period, the aqueous adhesive composition according to the first or second embodiment of the present invention is ready for use.

[0250] [Table 1]

[0251]

[0252]

[0253] 1) HMF (from Aldrich; purity > 99%);

[0254] 2) Phloroglucinol (from Alfa Aesar; purity 99%);

[0255] 3) 99% of the fructose comes from Aldrich;

[0256] 4) 99% of the glucose comes from Aldrich;

[0257] 5) 99% xylose, from Aldrich;

[0258] 6) 75% erythrose, from Aldrich;

[0259] 7) 99.5% sucrose, from Aldrich;

[0260] 8) Sodium hydroxide (from Aldrich; diluted to 30%);

[0261] 9) Olive pits, from Provencale;

[0262] 10) Chalk, from Lignoblast.

[0263] [Table 2]

[0264]

[0265]

[0266] 1) HMF (from Aldrich; purity > 99%);

[0267] 2) Phloroglucinol (from Alfa Aesar; purity 99%);

[0268] 3) 99% of the fructose comes from Aldrich;

[0269] 4) 99% of the glucose comes from Aldrich;

[0270] 5) 99.5% sucrose, from Aldrich;

[0271] 6) 99.5% phenol, from Aldrich;

[0272] 7) 99% of bisphenol A, from Aldrich;

[0273] 8) Lignin sulfonate lignin, from Aldrich;

[0274] 9) Sodium hydroxide (from Aldrich; diluted to 30%);

[0275] 10) Olive pits, from Provencale;

[0276] 11) Chalk, from Lignoblast.

[0277] Viscosity test

[0278] After preparing various aqueous adhesive compositions, the viscosity was measured at different time intervals. Using a Brookfield viscometer type and a spindle suitable for the target viscosity, the following procedure was used to measure the viscosity: the sample was transferred to a temperature-controlled chamber, up to approximately 150 ml (internal beaker graduations), while avoiding the formation of air bubbles, allowing the sample to self-regulate to the measurement temperature of 20°C within the indicated time (i.e., 1 to 20 minutes, depending on the initial temperature of the composition), a speed (e.g., 60 rpm) was selected and the spindle was rotated, allowing the spindle to stabilize (1 minute) before taking the first reading, and the result (viscosity in cP) was read on the digital display.

[0279] The results of the tests performed on the composition are summarized in Tables 3 and 4 below.

[0280] Scheme for producing test samples

[0281] The quality of the bond between wooden components is determined by a test in which the force required to separate the two wooden components from each other is measured by breaking the layer that joins the two components.

[0282] More specifically, each sample comprises three wooden elements, in this case made of wood with a density of 0.83 g / cm³. -3 The components, each made of beech wood, have a parallelepiped shape measuring 17cm x 17mm x 2.5mm. A layer of water-based adhesive composition is applied to one side of the first and third wooden components, covering their entire width. The three components are then joined together by applying layers of the composition to the first and third wooden components. Therefore, the total adhesive-coated surface area of ​​the sample formed from the three wooden components is 225cm². 2 The resulting sample composition was cured at 160°C for, for example, 300 seconds.

[0283] After curing, the specimen, consisting of three bonded elements, is placed in the jaws of a tensile testing machine and then stretched at a given temperature and a given rate (e.g., 1.5 mm / min and 20 °C in this case).

[0284] The specimens were cut according to standard NF EN 326.1 (1994) "Wood-based panels - sampling, cutting and inspection - Part 1: sampling and cutting of test specimens and expression of test results".

[0285] The adhesion level is characterized by measuring the "pull-out" strength (adhesive performance, in MPa) at which the three elements separate from each other by causing the adhesive layer to break. Any pull-out value greater than or equal to 1 MPa is considered good. Results are given on a basis of 100 relative to control composition C-1. A result greater than 60 is considered good because it represents a pull-out strength greater than 1 MPa.

[0286] The viscosity (in centipoise) of the adhesive compositions at 20°C was characterized over time. To evaluate the viscosity change of each composition over time, the results are given on a basis of 100 relative to each composition at time T0.

[0287] The results of the tests performed on the samples are summarized in Tables 3 and 4 below.

[0288] [Table 3]

[0289]

[0290]

[0291] [Table 4]

[0292]

[0293]

[0294] It was found that, similar to components made with composition C-1, components bonded with adhesive compositions C-2 to C-8 according to the first embodiment of the invention and adhesive compositions F-1 to F-3, G-1, and S-1 according to the second embodiment of the invention have a pull strength greater than 60. Therefore, they exhibit good or even superior bonding levels compared to the control composition C-1.

[0295] Regarding the viscosity characteristics of the adhesive compositions, it can be seen that the viscosity of composition C-1 changes very rapidly. At 20°C, the viscosity changes to 600% within 20 minutes. Regarding the viscosity characteristics of adhesive compositions C-2 to C-8 according to the first embodiment of the invention and adhesive compositions F-1 to F-3, G-1, and S-1 according to the second embodiment of the invention, the viscosity changes are observed to be slower than those of the control composition C-1. It takes more than 20 minutes, and even more than 40 minutes, to reach the 600% value.

[0296] It was found that components bonded with adhesive compositions C-2 to C-8 according to the first embodiment of the invention and adhesive compositions F-1 to F-3, G-1 and S-1 according to the second embodiment of the invention have a lower viscosity increase than control composition C-1. At the same time, surprisingly to those skilled in the art, compositions C-2 to C-4, C-7, G-1 and S-1 maintain good adhesion, and compositions C-5, C-6, C-8, F1, F-2 and F3 have improved adhesion.

[0297] IV – Other Exemplary Embodiments and Comparative Tests of the Invention

[0298] Three other aqueous adhesive compositions were prepared: one according to a first embodiment of the invention, one according to a second embodiment of the invention (hereinafter referred to as H-1 and I-1), and one not according to the invention (control composition, hereinafter referred to as C'-1). Their formulations (expressed as weight percentages) are shown in Tables 5 and 6 below. The amounts listed in the tables are the amounts of the components in a dry state based on a total of 100 parts by weight of the aqueous adhesive composition (i.e., the components and water).

[0299] The adhesive composition C'-1 is a control composition based on terephthalaldehyde and phloroglucinol.

[0300] The adhesive composition H-1 is an aqueous adhesive composition based on terephthalaldehyde, phloroglucinol and fructose according to a first embodiment of the present invention.

[0301] Adhesive composition I-1 is an aqueous adhesive composition based on terephthalaldehyde, phloroglucinol, fructose and phenol according to a second embodiment of the present invention.

[0302] The method for producing the adhesive composition is the same as described above.

[0303] [Table 5]

[0304] Adhesive composition C’-1 H-1 I-1 terephthalaldehyde (1) 13.6 10.4 10.4 Phloroglucinol (2) 18.2 18.2 9.1 Fructose (3) - 3.2 3.2 Phenol (4) - - 9.1 Sodium hydroxide (5) 7.6 7.6 7.6 resin water 61.5 61.5 61.5 Total solid weight of the adhesive composition 39.4 39.4 39.4 total 100 100 100

[0305] 1) 99% terephthalaldehyde (from Aldrich);

[0306] 2) Phloroglucinol (from Alfa Aesar; purity 99%);

[0307] 3) 99% of the fructose comes from Aldrich;

[0308] 4) 99.5% phenol, from Aldrich;

[0309] 5) Sodium hydroxide (from Aldrich; diluted to 30%).

[0310] After obtaining various water-based adhesive compositions, their viscosity was measured at 60°C at different time intervals according to the same scheme as described above.

[0311] The results of the tests performed on the composition are summarized in Table 6 below.

[0312] [Table 6]

[0313]

[0314]

[0315] Regarding the viscosity characteristics of the adhesive compositions, it can be seen that the viscosity of composition C'-1 changes very rapidly. At 60°C, the viscosity changes to 200% within 40 minutes. Regarding the viscosity characteristics of adhesive composition H-1 according to the first embodiment of the invention and adhesive composition I-1 according to the second embodiment of the invention, the viscosity changes are observed to be slower than those of the control composition C'-1. The 200% value is reached only after more than 70 minutes, and even more than 100 minutes.

[0316] In summary, the results of these various tests clearly demonstrate that the adhesive composition according to the invention constitutes an advantageous alternative to conventional adhesive compositions used in the absence of formaldehyde.

Claims

1. An aqueous adhesive composition, characterized in that, The aqueous adhesive composition comprises a thermosetting resin, the thermosetting resin being based on: - At least one aromatic compound A1, said aromatic compound A1 comprising at least one aromatic ring having at least two functional groups, one of which is an aldehyde functional group or a hydroxymethyl functional group, and the other functional groups are aldehyde functional groups or hydroxymethyl functional groups. - At least one aromatic polyphenol A2, said aromatic polyphenol A2 comprising at least one aromatic ring, said aromatic ring having at least two hydroxyl functional groups at the meta position relative to each other, wherein the two ortho positions of the at least one hydroxyl functional group are unsubstituted; and - At least one organic compound G, said organic compound G being selected from monosaccharide G1 or oligosaccharide G2. Among them, aromatic compound A1 corresponds to general formula (II): Where B and C represent CHO or CH2OH respectively, X represents O, NR1, S, SO or SO2, and R1 represents hydrogen or alkyl, aryl, arylalkyl, alkylaryl or cycloalkyl groups. Aromatic polyphenol A2 is selected from resorcinol, phloroglucinol, 2,2',4,4'-tetrahydroxydiphenyl sulfide, 2,2',4,4'-tetrahydroxybenzophenone, and mixtures of these compounds. Monosaccharide G1 is selected from fructose, xylose, erythrose, and mixtures of these compounds. Oligosaccharide G2 is sucrose. When organic compound G is selected from monosaccharide G1, the weight ratio of organic compound G to aromatic polyphenol A2 is between 1% and 23.7% of aromatic compound A1; when organic compound G is selected from oligosaccharide G2, the weight ratio of organic compound G to aromatic polyphenol A2 is between 1% and 40% of aromatic compound A1. The solid content of the thermosetting resin ranges from 10% by weight to 80% by weight of the solids in the water-based adhesive composition. The water content of the water-based adhesive composition ranges from 20% by weight to 95% by weight.

2. The composition of claim 1, further comprising: a phenol optionally substituted with a single alkyl group or a single alkenyl group, and / or at least one aromatic compound A3, said aromatic compound A3 comprising at least two aromatic rings having a single hydroxyl functional group, and it should be understood that at least one of the ortho or para positions of the hydroxyl group in each aromatic ring is unsubstituted.

3. The composition according to claim 2, wherein, The phenols optionally substituted with a single alkyl group are selected from phenol, o-cresol, m-cresol, p-cresol, or mixtures of these compounds.

4. The composition according to claim 2, wherein, Aromatic compound A3 corresponds to the general formula (X): Where Y1 represents an alkylene, arylene, arylalkylene, alkylarylene, cycloalkylene, or alkenylene group, which are substituted, and Y2 and Y3 are the same or different and represent H or an ether group.

5. The composition according to claim 4, wherein, Y2 and Y3 are adjacent to the hydroxyl functional group and represent H or OY4, where Y4 represents an alkyl, aryl, arylalkyl, alkylaryl, cycloalkyl, or alkenyl group.

6. The composition according to claim 4, wherein, Aromatic compound A3 contains at least two aromatic rings with a single hydroxyl functional group, and it should be understood that one of the adjacent positions of each aromatic ring with a single hydroxyl functional group is unsubstituted.

7. The composition according to claim 4, wherein, Aromatic compound A3 is selected from bisphenol A, lignin, or mixtures of these compounds.

8. The composition according to claim 2, wherein, Thermosetting resins are obtained by mixing the following substances in an alkaline solvent: - Aromatic compound A1; - Aromatic polyphenols A2; - Organic compound G, wherein organic compound G is selected from monosaccharide G1 or oligosaccharide G2; and - Phenols optionally substituted with a single alkyl group or a single alkenyl group, and / or aromatic compounds A3.

9. Use of the adhesive composition according to claim 1 for bonding at least two cellulose elements.

10. A method for bonding at least two cellulose elements, wherein: - Applying a layer of the aqueous adhesive composition according to claim 1 to at least one of the elements, and - Components are joined together by layers of an aqueous adhesive composition.

11. An adhesive assembly for two elements, the adhesive assembly comprising a layer of the aqueous adhesive composition according to claim 1, the layer bonding at least one element to the other.

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