Glue and method for manufacturing said glue

Abstract

A glue for lignocellulosic material, wherein said glue comprises at least two components, being -a first component which comprises a pre-reacted composition with at least reaction products of reducing sugars with a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides; -a second component comprising a second material, said second material comprising amine functional groups, for example said second material comprising amines and / or amides; wherein said glue comprises additives, and method for making such a glue.

Description

[0001] Glue and method for manufacturing said glue

[0002] This invention relates to a glue and a method for manufacturing such a glue. Said glue can be used for bonding plant particles together, for example for bonding (ligno)cellulosic materials, such as vegetable fibres and / or wood chips and / or wooden parts, to form boards. This glue can also be used to impregnate and / or coat paper. This glue can also be used for insulation material, for example for gluing mineral fibers, slag stone wool fibers, glass fibers, etc. This glue can be used to attach two objects to each other, for example two wood-based objects. For example said glue can be used to attach an edge tape to the edge of a wood-based panel or to attach a laminate, such as a high pressure laminate, to the surface of a wood-based board. Said glue can also be used to attach two wooden panels or two wood-based panels to each other. Said glue can thus be used for (ligno)cellulosic material. This invention thus also relates to a board comprising plant particles, such as vegetable fibres and / or wood chips and / or wood pieces, and a cured glue that bonds these plant particles to one another, wherein the cured glue is obtained by the curing of said glue. This invention also relates to a method for making such a board.

[0003] This glue can also be used for impregnating and / or coating sheets, for example papers, to form impregnated and / or coated sheets, such as impregnated and / or coated papers. A glue used for impregnating and / or coating a sheet can be indicated as a resin. A said sheet can be a paper, a textile, e.g. scrim or woven or non-woven, or a cardboard. Glue and resin are used interchangeably in this application. Such impregnated paper is extremely suitable for forming a laminate comprising a wood fiber board substrate (for example a MDF -medium density fiberboard- or an HDF -high density fiberboard- substrate) or a chipboard substrate and one or more impregnated papers bonded to this substrate, or for forming an HPL (high pressure laminate) or CPL (continuous pressure laminate) consisting of two or more bonded-together impregnated papers, or a HPL board (compact board) comprising at least 5, preferably at least 10, even more preferably at least 15, bonded-together impregnated papers or for forming a laminate comprising a thermoplastic based substrate, a mineral based substrate, or another substrate and one or more impregnated papers bonded to this substrate. This invention therefore also relates to an impregnated sheet, e.g. and impregnated paper, impregnated with the aforementioned glue.

[0004] This invention also relates to an object, such as a furniture, comprising at least two parts glued together by said glue.

[0005] This invention relates to boards comprising plant particles, for example lignocellulosic particles and / or cellulosic material. These plant particles can comprise one or more of the following materials: wood fibres, wood chips, wood shavings, wood layers, flax fibres, bamboo fibres, hemp fibres, other vegetable fibres, wood waste originating from e.g. the recycling of for example particle boards / wood fibreboards, etc. These cellulosic materials can be lignocellulosic materials. The boards are for example wood fibreboards, such as MDF and HDF, other wood-based boards such as particle boards, OSB (oriented strand board), multiplex boards. Such boards are also referred to as derived wood products or wood based panels or wood composites. The boards can also be non-wood- based fibreboards, such as flax boards, bamboo boards, hemp boards, etc. The above- mentioned boards may or may not comprise recycled material, such as recycled lignocellulosic material. For example, the cellulosic materials can comprise recycled materials originating from the recycling of for example particle boards, wood fibreboards or panels comprising such particle boards or wood fibreboards. This means that particle boards can comprise particles of recycled particle boards, or wood fibreboards can comprise particles of recycled wood fibreboards. The plant particles can thus also comprise non plant material such as glue residues, paint residues or impurities such as metal, plastic, etc.

[0006] The most common glue used in the production of such boards and the most common resin for impregnating paper, is an aminoplast polymer produced via a polycondensation reaction with formaldehyde, for example from urea and formaldehyde and converted to a urea formaldehyde resin (UF resin). Optionally, melamine is added and a melamine urea formaldehyde resin (MUF resin) is obtained, or melamine and phenol are added (MUPF resins: melamine urea phenol formaldehyde). Use can also be made of melamine formaldehyde resin (MF resin) or phenol formaldehyde resin (PF resin). The major advantages of such glues and resins, are their low cost -because of the use of generally available and inexpensive raw materials in their preparation and their high reactivity. Such glues and resins can emit formaldehyde during and after polymerisation under the influence of temperature, moisture, or pH modification. Efforts are increasingly being made in order to limit or even reduce to zero the emission of formaldehyde from boards. For this reason, formaldehyde-free glues for the production of the above-mentioned boards and formaldehyde-free resins for impregnating papers, have been and are being sought. Also the presence of melamine and / or phenol is not desirable.

[0007] A known formaldehyde-free glue for use in the production of derived wood products is composed of polymeric methylene diphenyl di-isocyanate (pMDI). An additional drawback is that this glue is based on fossil raw materials.

[0008] Bio-based glues for boards are already available, but the production of boards using these glues can be accompanied by drawbacks. Possible drawbacks include excessively low reactivity, uncontrolled / undesired prepolymerisation, limited adhesion strength, poor moistening properties, hydrolysis of the glue under the influence of water or high humidity. Examples of bio-based glues are glues based on lignin, plant flour such as soy flour, or sugars.

[0009] Bio-based glues based upon hyperbranched polyamides or comprising hyperbranched polyamides, the hyperbranched polyamides for example being hyperbranched polylysine, are known from WO 2023 / 218343 and WO 2023 / 148578. For these glues, a raw material comprising hyperbranched polyamides is used.

[0010] The present invention concerns in the first place an optimization of bio-based glues for lignocellulosic material, wherein in accordance with various embodiments, solutions are provided for the problems with such glues from the prior art.

[0011] Percentages and ratios are preferably dry matter weight percentages / ratios, unless otherwise indicated. According to a first aspect of the invention, the invention relates to a glue for cellulosic material, wherein said glue comprises at least two components, being

[0012] -a first component which comprises a pre-reacted composition with at least reaction products of reducing sugars with a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides;

[0013] -a second component comprising a second material, said second material comprising amine functional groups, for example said second material comprising amines and / or amides; wherein said glue comprises aldehydes, wherein the dry matter weight ratio of the aldehydes upon said reaction products is preferably between 0,1 and 3 wt%, more preferably between 0,2 and 2 wt%, for example 1 wt%.

[0014] According to a second aspect of the invention, which is optionally according the first aspect of the invention, the invention relates to a glue for cellulosic material, wherein said glue comprises at least two components, being

[0015] -a first component which comprises a pre-reacted composition with at least reaction products of reducing sugars with a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides;

[0016] -a second component comprising a second material, said second material comprising amine functional groups, for example said second material comprising amines and / or amides; wherein said glue comprises wetting agents, wherein the dry matter weight ratio of the wetting agents upon said reaction products is preferably between 0,1 and 2 wt%, more preferably between 0,2 and 0,5.

[0017] According to a third aspect of the invention, which is optionally according to the first and / or the second aspect of the invention, the invention relates to a glue for cellulosic material, wherein said glue comprises at least two components, being

[0018] -a first component which comprises a pre-reacted composition with at least reaction products of reducing sugars with a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides; -a second component comprising a second material, said second material comprising amine functional groups, for example said second material comprising amines and / or amides; wherein said glue comprises metal complexes, wherein the weight ratio of the dry matter weight metal complexes upon the dry matter weight glue is preferably between 0,1 and 2 wt%, more preferably between 0,2 and 0,5 wt%, and wherein preferably the metal complexes are chosen from the list: Zn(OAc)2, Mg(OH)2, Ca(OH)2, titanium acrylates, organozirconium compounds and ferric sulphate (iron(III) sulphate, F 62(804)3).

[0019] According to a fourth aspect of the invention, which is optionally according to the first and / or the second and / or the third aspect of the invention, the invention relates to a glue for cellulosic material, wherein said glue comprises at least two components, being -a first component which comprises a pre-reacted composition with at least reaction products of reducing sugars with a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides;

[0020] -a second component comprising a second material, said second material comprising amine functional groups, for example said second material comprising amines and / or amides; wherein the difference in acidity / alkalinity (pH) of the first component and the second component, is at most 1 pH, preferably at most 0,5 pH, most preferably at most 0,2 pH and wherein preferably the second component has a pH of between 9 and 11, more preferably of between 9,4 and 10,2, for example 9,8.

[0021] Preferably the acidity of the second component results from the manufacturing process of said second material. Further preferably, the acidity of the first component is adapted such that it complies with the acidity of the second component. With the acidity / alkalinity of the first component and the acidity / alkalinity of the second component are preferably indicated the acidity / alkalinity when adding said first component to the second component to form said glue.

[0022] According to a fifth aspect of the invention, which is optionally according to the first and / or the second and / or the third and / or the fourth aspect of the invention, the invention relates to a glue for cellulosic material, wherein said glue comprises at least two components, being

[0023] -a first component which comprises a pre-reacted composition with at least reaction products of reducing sugars with a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides;

[0024] -a second component comprising a second material, said second material comprising amine functional groups, for example said second material comprising amines and / or amides; wherein said glue comprises viscosity reducing agents, wherein the dry matter weight ratio of the viscosity reducing agents upon said reaction products is preferably between 0,1 and 2 wt%.

[0025] According to a sixth aspect of the invention, which is optionally according to the first and / or the second and / or the third and / or the fourth and / or the fifth aspect of the invention, the invention relates to a glue for cellulosic material, wherein said glue comprises at least two components, being

[0026] -a first component which comprises a pre-reacted composition with at least reaction products of reducing sugars with a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides;

[0027] -a second component comprising a second material, said second material comprising amine functional groups, for example said second material comprising amines and / or amides; wherein said glue comprises phosphates, wherein the dry matter weight ratio of said phosphates upon said reaction products is preferably between 0,1 and 2 wt%. Said phosphates preferably function as crosslinker.

[0028] According to a seventh aspect of the invention, which is optionally according to the first and / or the second and / or the third and / or the fourth and / or the fifth and / or sixth aspect of the invention, the invention relates to a glue for cellulosic material, wherein said glue comprises at least two components, being -a first component which comprises a pre-reacted composition with at least reaction products of reducing sugars with a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides;

[0029] -a second component comprising a second material, said second material comprising amine functional groups, for example said second material comprising amines and / or amides; wherein said glue comprises thickening agents, wherein said thickening agents are preferably carboxymethyl cellulose and / or gum. Preferably the dry matter weight glue comprises between 1 and 4 wt% of said thickening agents, preferably between 2 and 3 wt%, for example 2,5 wt%.

[0030] According to an eight aspect of the invention, which is optionally according to the first and / or the second and / or the third and / or the fourth and / or the fifth and / or sixth and / or seventh aspect of the invention, the invention relates to a glue for cellulosic material, wherein said glue comprises at least two components, being

[0031] -a first component which comprises a pre-reacted composition with at least reaction products of reducing sugars with a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides;

[0032] -a second component comprising a second material, said second material comprising amine functional groups, for example said second material comprising amines and / or amides; wherein said glue comprises surfactants, preferably chosen from the list of soaps, detergents, salts and alcohols. Preferably the dry matter weight glue comprises between 1 and 4 wt% of said surfactants, preferably between 2 and 3 wt%, for example 2,5 wt%.

[0033] According to an ninth aspect of the invention, which is optionally according to the first and / or the second and / or the third and / or the fourth and / or the fifth and / or sixth and / or seventh and / or eight aspect of the invention, the invention relates to a glue for cellulosic material, wherein said glue comprises at least two components, being

[0034] -a first component which comprises a pre-reacted composition with at least reaction products of reducing sugars with a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides; -a second component comprising a second material, said second material comprising amine functional groups, for example said second material comprising amines and / or amides; wherein said glue comprises acrylates, wherein said acrylates are preferably diacrylates, triacrylates or multi acrylates. Preferably the dry matter weight glue comprises between 2 and 15 wt% of acrylates, for example 5 wt% or 10 wt%.

[0035] Said glues, according to all the abovementioned aspects and according to all possible combinations of the abovementioned aspects, are very suitable for lignocellulosic material. For example said glues can be used to glue lignocellulosic particles, such as plant fibers, wood chips, wood shavings, etc. together, as such to form boards. Said glues can also be used to laminate different sheets, for example paper sheets, together to form laminates such as high pressure laminate (HPL) or compact board. During manufacturing of said boards and laminates, the glue cures (hardens). Said glues can also be used to glue mineral particles, such as MgO, together or mixtures of lignocellulosic particles and mineral particles. Said glue can also be used to impregnate / coat sheets, such as paper, textile, glass fibers sheets, cardboard. Said glue can also be used to glue different parts together, e.g. to glue parts of a furniture together.

[0036] For all the abovementioned aspects, said reaction products of the pre-reacted composition preferably comprise Maillard reaction products derived from the Maillard reaction between said amine functional groups, for example between the amine functional groups of the amines and / or amides, and the reducing sugars. Said reaction products are preferably obtained by mixing said first material with said reducing sugars and by adding heat, as such initiating the Maillard reaction. The Maillard reaction is the general term for a complex series of chemical reactions that occur between reducing sugars and amine functional groups. Reducing sugars are necessary for the Maillard reaction. To form said first component, carbohydrates are provided, said carbohydrates being reducing sugars and / or being converted to reducing sugars. For example, use may can be made of sucrose, which is for example converted to glucose and fructose. Sucrose is a widely occurring sugar and is a cheap bio-based source of carbohydrate. It is possible to provide invert sugar to form said first component. The carbohydrates used may also comprise only glucose or comprise only fructose. Of course other reducing sugars can be used.

[0037] For all the above-mentioned aspects, preferably said first material comprises amines and / or amides comprising said amine functional groups. The weight of said reaction products can be approximately the weight of said reducing sugars and said amines and / or amides. Therefore the above-mentioned dry matter weight ratio’s upon said reaction products, could also be indicated as the dry matter weight ratio’s upon said reducing sugars and said amines and / or amines of the first material. Further said first material could comprise at least 90 wt%, or at least 95 wt% amines and / or amides based on dry matter weight. Therefore the above-mentioned dry matter weight ratio’s upon said reaction products, could also be indicated as the dry matter weight ratio’s upon said reducing sugars and said first material, or upon said pre-reacted composition. Of course, during the formation of said pre-reacted composition, water can be released, such that most preferably said dry matter weight ratio is a dry matter weight ratio upon said reducing sugars and said first material or upon said reducing sugars and said amines and / or amines. The first material and the second material can or cannot have the same composition.

[0038] Said glue is made by combining materials. With based on dry matter weight glue is preferably indicated based on dry matter weight of the combined materials, before combining said materials to form said glue.

[0039] Preferably the dry matter weight ratio of the aldehydes upon said reducing sugars and said amines and / or amines of the first material, is between 0,1 and 3 wt%. Preferably the dry matter weight ratio of the aldehydes upon said reducing sugars and said first material, is between 0,1 and 3 wt%. Preferably the dry matter weight ratio of the aldehydes upon said pre-reacted composition, is between 0,1 and 3 wt%.

[0040] Preferably the dry matter weight ratio of the wetting agents upon said reducing sugars and said amines / amides of the first material, is preferably between 0,1 and 2 wt%. Preferably the dry matter weight ratio of the wetting agents upon said reducing sugars and said first material, is between 0,1 and 2 wt%. Preferably the dry matter weight ratio of the wetting agents upon said pre-reacted composition, is between 0,1 and 2 wt%. Preferably the dry matter weight ratio of the viscosity reducing agents upon said reducing sugars and said amines / amides of the first material is preferably between 0,1 and 2 wt%. Preferably the dry matter weight ratio of the viscosity reducing agents upon said reducing sugars and said first material is preferably between 0,1 and 2 wt%. Preferably the dry matter weight ratio of the viscosity reducing agents upon said reducing sugars and said pre-reacted composition is preferably between 0, 1 and 2 wt%.

[0041] Preferably the dry matter weight ratio of said phosphates upon said reducing sugars and said amines / amides of the first material is preferably between 0,1 and 2 wt%. Preferably the dry matter weight ratio of said phosphates upon said reducing sugars and said first material is preferably between 0,1 and 2 wt%. Preferably the dry matter weight ratio of said phosphates upon said reducing sugars and said pre-reacted composition is preferably between 0,1 and 2 wt%.

[0042] For all the above-mentioned aspects, the Maillard reaction can take place by means of heat. To form said pre-reacted composition, preferably heat is added, such that the reducing sugars and the amines and / or amines, react well with each other. By having said pre-reacted composition, and preferably by having said Maillard reaction products, curing times of the glue can be shortened and / or the reactivity of the glue can be higher. The result is that with such glue, boards and laminates can made in a fast manner. By adding said second component to the first component, further amine functional groups are present in the glue, such that the glue is further curable.

[0043] For all the above-mentioned aspects, this first component can only comprise said prereacted composition, but can also comprise other compounds. For example the first component can comprise said aldehydes and / or wetting agents and / or metal complexes and / or said viscosity reducing agents and / or said phosphates. For example the first component comprises said aldehydes. For example the first component comprises said aldehydes and said viscosity reducing agents. For example said first component comprises said aldehydes, said wetting agents and said viscosity reducing agents. For example said first component comprises said aldehydes and said phosphates. Preferably, if said first component comprises one or more of said other compounds, these other compounds are added to the pre-reacted composition to form said first component, and this after the complete formation of said reaction products of the pre-reacted composition. For example first the pre-reacted composition is made with the aid of heat, then said pre-reacted composition is cooled, after which said other compounds are added to said pre-reacted composition to form said first component. In this manner, undesirable pre-reactions of said other compounds with the reducing sugars and / or amine functional groups can be avoided, such that said other compounds are only active when desired, e.g. are only active when curing said glue.

[0044] For all the above-mentioned aspects, for formation of the pre-reacted composition, preferably the dry weight ratio of amines and / or amides upon reducing sugars is between 3:100 and 35: 100, preferably between 6:100 and 25:100, for example is 9:100. With such a ratio, a good balance is obtained between said reaction products and amines and / or amides of the second component, such that curing can take place in a fast manner and still a sufficiently dense cured network is obtained.

[0045] For all the above-mentioned aspects, if, to form said pre-reacted composition, sucrose is used as a raw material, then preferably additives such as an acid or salts of an acid, for example chloric acid (such as HC1) or salts of a hypochlorous acid (such as NaOCl), are added so that sucrose is satisfactorily converted to glucose and fructose. Alternatively or in addition, use can be made of an enzyme to covert the sucrose. This conversion can be done before adding the first material to the sucrose to form said pre-reacted composition, but can also be done during or after adding of said first material.

[0046] For all the above-mentioned aspects, if said second component comprises amines, said amines are preferably diamines, such as hexamethylenediamine (HDMA). If said second component comprises amides, said amides preferably comprise polyamides, such as hyperbranched polyamides. Said first material can also comprise abovementioned amines and amides. Said first material and said second material can or cannot have the same composition. For all the above-mentioned aspects, preferably both said first component and said second component are aqueous solutions, e.g. are thus water-based.

[0047] In the first aspect of the invention, said aldehydes enhance the crosslinking of the glue and / or enlarge the amount of advanced glycation products. Said advanced glycation products are a type of Maillard reaction products. The result is that with this glue stronger and stiffer board material can be obtained. A board material made with this glue therefore can have the desired tensile strength, bending strength and E-modulus. With the aid of this glue, one can choose to manufacture boards with better properties, in comparison with boards manufactured with existing glues based on carbohydrates and amines and / or amides. However, one can also choose to use less glue, than with boards manufactured with existing glues based on carbohydrates and amines and / or amines, to obtain similar properties. By means of said aldehydes, one can also choose to lower the content of the first material and / or the second material in the glue. Good results are obtained for a first and second material comprising amines and / or amides, when the percentage by weight of amines and / or amides upon the total weight of amines and / or amides and carbohydrates is at least 15.

[0048] As already indicated, said aldehydes are preferably part of the first component. However said aldehydes can also form a separate component or are part of a separate component, or can be part of the second component. If said aldehydes are a separate component, said aldehydes are preferably only added shortly before using said glue, for example at most 12h before using this glue. This way, relatively high amounts of aldehydes, for example a glue with up to 1 or 2 wt% of aldehydes, can be used without having unwanted precuring of the glue.

[0049] For all the above mentioned aspects of the invention, in a preferred embodiment, said first material at least comprises amides and / or said second material at least comprises amides, wherein said amides comprise, and preferably are, polyamides obtained by polymerization of amino acids, and wherein more preferably the polyamides comprise or consist of hyperbranched polyamides. Said pre-reacted composition then preferably comprises at least reaction products of amides with reducing sugars. It has been found that with such polyamides, the aldehydes significantly enhance the crosslinking during curing of said glue. Also such polyamides can be bio-based.

[0050] For all the above-mentioned aspects, said hyperbranched polyamides (highly branched polyamides) are highly branched three-dimensional macromolecules. High / strong branching means that the polyamides are not linear and it also means that there is a significant number of branchings. This signifies that more than 3, preferably more than 5 and even more preferably more than 10 branchings are present in the polyamide macromolecule. Said hyperbranched polyamides are preferably based on amino acids, for example polycondensed amino acids, wherein these amino acids are for example produced with the aid of bacteria. These are then bio-based hyperbranched polyamides. In order to form these hyperbranched polyamides, it is possible to choose to block no or virtually no groups or positions of the amino acids. It is thus possible to choose to not block the a position and / or the a position of the amino acids. Bacteria, such as Corynebacterium (Gram-positive) or Escherichia coli (Gram-negative), can by fermentation convert amino acids chemically in a directed manner for example mainly to lysine and a proportion of glutamine. When the hyperbranched polyamides are based on polycondensed amino acids, it is not necessary that these are only based on one type of amino acid. When use is made of bacteria that for example form mainly lysine and a small proportion of other amino acids such as glutamine, both the lysine and the glutamine may be used for the production of the hyperbranched polyamides, so that an additional purification step of the amino acids is superfluous and the production of the hyperbranched polyamides can take place in an ecological manner. If the amino acids substantially comprise lysine or for example comprise at least 80 weight percentage, preferably at least 90 weight percentage, of lysine, said hyperbranched polyamides can be indicated as hyperbranched polylysine. The hyperbranched polyamides can also be hyperbranched polyarginine, hyperbranched polyglutamine, hyperbranched polyasparagine, hyperbranched polyhistidine. The hyperbranched polyamides can also be obtained from mixtures of amino acids, wherein said amino acids are preferably chosen from the list of lysine, arginine, glutamine, asparagine and histidine. If said hyperbranched polyamides do not comprise a dominant amino acid, said hyperbranched polyamides could be indicated as hyperbranched poly amino acids. Most preferably said first material and / or said second material comprises hyperbranched polylysine. More preferably the dry matter weight of said first material and / or said second material comprises at least 90 wt% of hyperbranched polylysine, most preferably at least 95 wt% of hyperbranched polylysine. Said hyperbranched polylysine can have a degree of branching of between 0,1 and 0,6, for example of between 0,25 and 0,4, for example 0,23 or 0,26 or 0,27 or 0,29 or 0,31 or 0,35 or 0,45 or 0,50 or 0,55. The degree of branching can be measured by H-NMR spectroscopy.

[0051] For all the above-mentioned aspects, the first and the second material preferably comprise at least 90 wt% of polyamides obtained by polymerisation of amino acids, for example obtained by polymerisation of amino acids which comprise at least 90 wt% of lysine. Said polyamides can thus be polylysine. Said polylysine can or cannot be hyperbranched. For example said polyamides can comprise at least 80 wt% of hyperbranched polylysine.

[0052] For all the above-mentioned aspects, said hyperbranched polyamides can have a sufficiently high number average molecular weight, and this while still being in a dissolved form in the first material and / or the second material. For example said hyperbranched polyamides can have a number average molecular weight of at least 5000 g / mol. For example the hyperbranched polyamides have a number average molecular weight of between 5000 and 50000 g / mol, or for example between 10000 and 25000 g / mol. The reactivity of the hyperbranched polyamides is optimal if the number average molecular weight is greater than 5000 g / mol, and the gluing can be carried out quite favourably when the number average molecular weight is less than 50000 g / mol. Preferably, 90 wt% of the hyperbranched polyamides, even more preferably 95 wt%, and most preferably 99 wt%, have a molecular weight that is greater than 20000 g / mol. This also allows favourable production of board material. The number average molecular weight of hyperbranched polyamides can be determined for example by low angle laser light scattering (LALLS). Alternatively or additionally, the number average molecular weight can be determined by gel permeation chromatography (GPC). For all the above-mentioned aspects, another benefit of such polyamides, especially said hyperbranched polyamides, is that said molecules are capable of adhering to formaldehyde, for example binding it chemically via addition reactions, which allows any emission of formaldehyde from boards comprising said glue to be kept extremely low. Plant particles comprise a certain amount of formaldehyde and / or comprise functional groups which can be converted to formaldehyde during pressing, recycled plant particles can comprise higher amounts of formaldehyde. For forming the board material, one can for example use plant particles comprising recycled content, such as for example recycled refined particle boards. These recycled refined particle boards may comprise a certain amount of formaldehyde. The use of hyperbranched polyamides ensures that even when one works with recycled material, the emission of formaldehyde is not too high.

[0053] For all the above-mentioned aspects, said first material and / or said second material can be obtained from polymerisation of a fermentation broth comprising amino acids, and said first material and / or second material can further comprises one or more components of the following list:

[0054] -a carbon source, such as carbohydrates;

[0055] -a nitrogen source, such as com steep liquor, yeast extract, tryptone, peptone, soybean cake hydrolysate, casein hydrolysate and / or urea;

[0056] -dry cellular matter, for example remnants of micro-organisms;

[0057] -salts, such as potassium salts or magnesium salts or phosphate salts;

[0058] -enzymes excreted by micro-organisms during fermentation;

[0059] -catalysts, such as lewis acids, lewis bases, Bronsted acids or Bronsted bases.

[0060] For all the above-mentioned aspects, said hyperbranched polyamides of said first and / or second material can have incorporated crosslinkers, preferably crosslinkers chosen from the list of crosslinkers with at least one alcohol end group and / or cross linkers with at least one amine end group and / or trifunctional crosslinkers. Such hyperbranched polyamides then do not only comprise amino acids, but also crosslinkers. For all the above mentioned aspects, in a very preferred embodiment, the reducing sugars comprise glucose and / or fructose, and preferably are a mixture of glucose and fructose. For example invert sugar can be used as a material to form said pre-reacted composition. For example sucrose can be used as a material to form said pre-reacted composition, wherein before and / or during and / or after adding said sucrose to said first material, said sucrose is inverted to glucose and fructose, and this for example with the aid of acids. If sucrose is used, then preferably at least 95 wt% of the sucrose gets inverted to glucose and fructose, more preferably at least 99 wt%. To form said pre-reacted composition, preferably a third material comprising carbohydrates is mixed with said first material. Said third material preferably comprises, initially and / or by inversion, at least 95 wt% of reducing sugars. It has been found that, if non-reducing sugars are used, the inversion is crucial to obtain a glue with the desired characteristics.

[0061] In a very preferred embodiment of the first aspect of the invention, the aldehydes are chosen from the list of: glyoxal, glutaraldehyde, succinaldehyde, malondialdehyde, or mixtures thereof. Glyoxal is the most preferred aldehyde, since this aldehyde has high reactivity and enhances crosslinking of the glue the most. Glyoxal is very good activator of the pre-reacted composition. Preferably said aldehydes consist of glyoxal.

[0062] According to all the aspects of the invention, in a very preferred embodiment, said first material and said second material comprise amines and / or amides, and wherein preferably one, two or all the following features are present:

[0063] -the first material and the second material substantially have the same composition. For example said first material and said second material are taken from the same raw material / batch;

[0064] -for the pre-reacted composition, the weight ratio of amines and / or amines, upon the reducing sugars, is between 4 and 30 wt%, preferably being between 5 and 25 wt%, for example is 6 wt% or 9 wt%;

[0065] -for the glue, the weight ratio of reducing sugars upon amines and / or amides is between 50:50 and 90:10, for example between 55:45 and 80:20, preferably between 60:40 and 70:30. For example the weight ratio of reducing sugars upon amines and / or amides can be 59:41 or 58:42 or 61 :39 or 62:38. For all the above-mentioned aspects, most preferably said first material and said second material are obtained from the same raw material or of similar raw material. For example said first material and said second material can be obtained from the same batch. For example said raw material can comprise hyperbranched polyamides obtained by polymerisation of amino acids chosen from the list of: arginine, glutamine, histidine and lysine. This means preferably that a part of said raw material is provided to form said first material and that another part of said raw material is provided to form said second material.

[0066] Said wetting agents of the second aspect of the invention, enhance the application of said glue upon the (ligno)cellulosic material. For example, for lignocellulosic particles such as wood fibers or wood chips, said glue can more easily be homogeneously spread upon said lignocellulosic particles. Further, with the aid of said wetting agents, cold tack is improved, such that a nice coherent cake comprising lignocellulosic material and said glue can be formed, wherein said cake can be well pressed to form boards. Further also for laminates, said cold tack can be beneficial, for example when forming stacks of glue- coated / glue-impregnated sheets, e.g. paper sheets.

[0067] As already indicated, said wetting agents can be part of the first component. However said wetting agents can also form a separate component or are part of a separate component, or can be part of the second component. Preferably, said first component comprises said wetting agents. In the latter embodiment, said wetting agents are preferably added to the pre-reacted composition to form said first component, and this after the complete formation of said reaction products. For example first the pre-reacted composition is made with the aid of heat, then said pre-reacted composition is cooled, after which said wetting agents are added to said pre-reacted composition to form said first component. Surprisingly, it has been found, that a very stable first component is formed with a good shelf life, and that this glue has excellent wetting characteristics for lignocellulosic material. Preferably, for the second aspect of the invention, the wetting agents are chosen from the list of: glycerol, sulphates -such as sodium lauryl sulphate-, propylene glycol, and mixtures thereof. Glycerol has been found to be a very suitable wetting agent, which does not negatively influence the shelf life of the glue. Preferably said wetting agents consist of glycerol.

[0068] The metal complexes, according to the third aspect of the invention, are preferably chosen from the list: Zn(0Ac)2, Mg(0H)2, Ca(0H)2, titanium acrylates, organozirconium compounds, ferric sulphate or mixtures thereof. The above-mentioned metal complexes are highly suitable for enhancing the crosslinking of the glue, during curing of the glue. Preferably said metal complexes consist of one of the molecules of the abovementioned list.

[0069] The phosphates of the sixth aspect of the invention can consist of disodium hydrogen phosphate.

[0070] In specific embodiments, for all the abovementioned aspects, the glue comprises two- functional epoxides and / or multifunctional epoxides. Said epoxides can be part of the first component and be added to said pre-reacted composition for forming said first component, after complete formation of said pre-reacted composition. However said epoxides are preferably a separate component of the glue and are preferably added after adding said first component to said second component. The reactivity of the glue is more controllable with two-functional epoxides. The reactivity of the glue can be higher with multifunctional epoxides. Said epoxides can comprise trimethylolpropane triglycidyl ether (CAS number 30499-70-8). These epoxides can for example comprise one or more oxirane end groups and preferably comprise two or more oxirane end groups, such as trioxirane. These epoxides may for example be created via bio-based routes from lignin or aniline, such as glycerol diglycidyl ether, and / or ethylene glycol diglycidyl ether. These epoxides may for example comprise diglycidyl ether of vanillyl alcohol and / or phloroglucinol tris epoxy. It is only when pressure and temperature are added in the press for curing said glue, that the epoxide becomes active. If said epoxides, such as two- functional or multifunctional epoxides are present, then preferably the dry matter weight ratio of the epoxides upon said reaction products of the pre-reacted composition, is preferably between 0,1 and 5 wt%, for example 2 wt%, 3 wt% or 4 wt%, and / or wherein the dry matter weight ratio of the epoxides upon said reducing sugars and said amines / amides of the first material, is preferably between 0,1 and 5 wt%, for example 2 wt%, 3 wt% or 4 wt%, and / or wherein the dry matter weight ratio of the epoxides upon said reducing sugars and said first material, is between 0,1 and 2 wt%, for example 2 wt%, 3 wt% or 4 wt%,. These epoxides enhance the crosslinking of the glue and are especially beneficial for forming board material, since said board material can be faster cured. Said epoxides can also enhance the water resistant properties. Said epoxides, for example the two-functional epoxides, can enlarge the molecular weight of the formed products during pressing, such that molecules with larger backbones are formed.

[0071] According to the fourth aspect of the invention, the difference in acidity / alkalinity (pH) of the first component and the second component, is at most 1 pH, preferably at most 0,5 pH, most preferably at most 0,2 pH and wherein preferably the second component has a pH of between 9 and 11, more preferably between 9,4 and 10,2, for example 9,8. The benefit of the first component and the second component having approximately the same acidity, is that after adding the first component and the second component together to form the glue, the glue can remain stable for a longer time, for example can remain stable for at least 6h, preferably at least 12h, more preferably at least 24h. Also mixing of said components is more easily. The second component can for example comprise a water based dispersion of hyperbranched polyamides, said hyperbranched polyamides being obtained by polymerisation of amino acids. Such a water-based dispersion of hyperbranched polyamides can be slightly alkaline, for example can have a pH of between 8 and 11. Preferably it is the second component which determines the acidity and the first component is tailormade to have the approximately same acidity as the second component.

[0072] Furter preferably, the first component comprises bases, for example potassium carbonate (K2CO3), and wherein preferably the dry matter weight ratio of bases upon said reaction products is preferably between 0,5 and 10 wt%, for example between 1 wt% and 5 wt%, for example 2,5 wt% or 4 wt% or 6 wt%. For example the dry matter weight ratio of bases upon said first material (or upon said reducing sugars and said amines and / or amides of the first material) is between 0,5 and 10 wt%, for example between 1 wt% and 5 wt%, for example 2,5 wt% or 4 wt% or 6 wt%. Said pre-reacted composition is for example slightly acidic. By adding said bases, the first component can have approximately the same acidity as the second component. These bases can be added to the pre-reacted composition after forming said pre-reacted composition. This to bring the first component to the desired acidity. Said bases can also be added before or during forming of the pre-reacted composition and this to speed up the formation of the prereacted composition.

[0073] According to the fifth aspect, the glue comprises viscosity reducing agents. Said viscosity reducing agents improve the wettability of the lignocellulosic material. Especially in manufacturing processes where the lignocellulosic material has a low amount of water when applying the glue upon the lignocellulosic material, for example during gluing of wood chips, said viscosity reducing agents ensure that the glue gets evenly spread upon the lignocellulosic material.

[0074] Said viscosity reducing agents are chosen from the list of amino acids, sulphites, sulphates and sulphonates and mixtures thereof. For example said viscosity reducing agents can comprise sodium sulphite or sodium sulphate or sodium dodecyl sulphonate. Said viscosity reducing agents can consist of sodium sulphite or sodium sulphate or sodium dodecyl sulphonate. Most preferably said viscosity reducing agents comprise or consist of amino acids such as L-lysine or L-arginine. The amino acids can also comprise B-aniline. When between 0, 1 and 1 wt% of amino acids upon said reaction products of the pre-reacted composition are added (or upon the first material or upon the reducing sugars and the amines and / or amides of the first material), a viscosity reduction of the glue of between 5 and 30% can be obtained. Preferably said amino acids are added after forming the pre-reacted composition to form the first component.

[0075] In a very preferred embodiment, the glue is a glue according the first aspect and according to the fifth aspect. The glue then has good wetting abilities and crosslinking abilities. Here said glue is further preferably according to the fourth embodiment, such that the first and the second component can be well mixed in a stable manner. Additionally said glue is also according to the third aspect and / or the second aspect and / or the sixth aspect.

[0076] In another preferred embodiment, the glue is according to the first aspect and according to the second aspect. The glue then has good wetting abilities and crosslinking abilities. Here said glue is also preferably according to the fourth aspect, such that the first and the second component can be well mixed in a stable manner. Additionally said glue is also according to the third aspect and / or the fourth aspect and / or the sixth aspect.

[0077] In an embodiment, the glue is according to the second aspect and / or the fifth aspect. The glue has then good wetting abilities. Here said glue is also preferably according to the fourth embodiment, such that the first and the second component can be well mixed in a stable manner. Additionally said glue is also according to the third aspect.

[0078] The thickening agents of the seventh aspect ensure that said glue can has the desired viscosity, e.g. a sufficient high viscosity. For certain applications, it is desired that glue has a higher viscosity, for example a viscosity of at least 20 mPa s, at 20°C and 1.013 bar, preferably at least 40 mPa s, more preferably at least 50 mPa s, more preferably at least 100 mPa s, more preferably at least 500 mPa s, more preferably at least 1000 mPa s, most preferably at least 2000 mPa s. The latter is beneficial if the glue is used as a so- called wood glue to glue wood containing objects to each other, or to glue a HPL to a substrate such as particle board substrate or a wood fiberboard substrate. If such glue is used to glue a HPL to a said substrate, said substrate can comprise a glue according to one or more of the other described aspects and also said HPL can comprise a glue according to one or more of the other described aspects. As such it is possible to use only or substantially bio-based glues for wood based panels, for example for furniture. If said thickening agents are present, then preferably no viscosity reducing agents are present and the glue is not according to the fifth aspect.

[0079] The surfactants of the eight aspect of the invention ensure that said glue forms a nice film when being applied. For certain applications, it is desired that the glue can easily be evenly applied. The latter is beneficial if the glue is used as a so-called wood glue to glue wood containing objects to each other, or to glue a HPL to a substrate such as particle board substrate or a wood fiberboard substrate. If such glue is used to glue a HPL to a said substrate, said substrate can comprise a glue according to one or more of the other described aspects and also said HPL can comprise a glue according to one or more of the other described aspects. As such it is possible to use only or substantially bio-based glues for wood based panels, for example for furniture. Preferably said glue according to the eighth aspect is also according to the seventh aspect, such that is has the desired viscosity and forms a good film.

[0080] The acrylates of the ninth aspect of the invention are excellent crosslinkers. They are for example excellent crosslinkers with amines through the Michael addition reaction. The acrylates are preferably diacrylates, triacrylates or multi acrylates, this being molecules with two acrylate side chains, three acrylate side chains or more acrylate side chains. These acrylates can be small molecules, such as for example an aromatic with acrylate side chains, or an oligomer with acrylate side chains or a polymer with acrylate side chains. Such acrylates can take up between 3 and 15 wt% of the total dry matter weight of the glue, for example 5 wt% or 10 wt%. Surprisingly it was found that acrylates are excellent crosslinkers for said glue, such that curing of said glue can be accelerated and strong materials are obtained, for example strong laminates or strong wood-based boards. Said acrylates are also homogeneously spread in said glue, such that said acrylates can well perform its crosslinking function during curing of said glue.

[0081] Said glue, according to all the above mentioned aspects or combination of aspects, can comprise further additives for enhancing water resistance and / or fire resistance and / or antistatic properties. For example said further additives are preferably chosen from the list of

[0082] -a silicon containing compound, such as fumed silica or silanes or polysiloxanes;

[0083] -a metallic soap;

[0084] -a thermoplastic material;

[0085] -inorganic fillers such as CaCCh, talc, vermiculite;

[0086] -moisture absorbing material; -thermo-initiator;

[0087] -epoxy;

[0088] -zero-poisson’s ratio material;

[0089] -wax, for example wax emulsions.

[0090] Preferably said further additives are present in amount of between 1% and 15% by weight based upon the dry matter weight of the glue. Wax, more in particular wax emulsions, are very sufficient to provide the glue with water resistant properties. Said wax emulsion can have a HLB value of between 10 and 11. The wax emulsion can be a wax emulsion in water or a wax emulsion in oil. The wax can comprise one or more of the list of: paraffin wax, carnauba wax, bee wax, candelilla wax or rice bran wax.

[0091] According to first variants of the first and / or second and / or third and / or fourth and / or fifth and / or sixth and / or seventh and / or eight and / or ninth aspect of the invention, the first component, instead of comprising said pre-reacted composition, the first component comprises reducing sugars, e.g. for example only comprises above-mentioned third material such as invert sugar, and said second component comprises amines and / or amines. Said amines and / or amides of the second component preferably being all the amines and / or amides of the glue. Said amines and / or amines of the second component preferably being polyamides obtained by polymerisation of amino acids, such as (hyperbranched) polylysine. For said glue, the first component and the second component and possible other compounds can be added to each other and stored together. However it is also possible that said first component and the second component and possible other compounds are only added to other shortly before using said glue, for example at most 12h before using said glue. Said additional features of above-mentioned first and / or second and / or third and / or fourth and / or fifth and / or sixth and / or seventh and / or eight and / or ninth aspect of the invention, are also beneficial for a glue which does not make use of a said pre-reacted composition. Said pre-reacted composition, thus firstly reacting reducing sugars with some of the amines and / or amides, such that the glue already comprises said reaction products, is optional for these variants. For example the aldehydes will also enhance crosslinking. The wetting agents will enhance wetting of the lignocellulosic material. The viscosity reducing agents will improve the pumpability of the glue. The metal complexes will enhance the crosslinking during curing of the glue. Said phosphates will also enhance the crosslinking. Said thickening agents can provide the glue with the desired viscosity. Said surfactants can enhance the ease of application of the glue. The acrylates will enhance crosslinking of the glue. By having said first component and said second component at comparable acidity, mixing of said components and reaction between said components is enhanced.

[0092] For said above-mentioned variants, one or more of the following features are preferably present:

[0093] -the glue comprises aldehydes and the dry matter weight ratio of the aldehydes upon the glue is between 0,05 and 1,5 wt%;

[0094] -the glue comprises wetting agents and the dry matter weight ratio of the wetting agents upon the glue is between 0,05 and 1,5 wt%;

[0095] -the glue comprises viscosity reducing agents and the dry matter weight ratio of the viscosity reducing agents upon the glue is between 0,05 and 1,5 wt%;

[0096] -the glue comprises phosphates and the dry matter weight ratio of said phosphates upon said glue is preferably between 0,05 and 1,5 wt%;

[0097] -the glue comprises thickening agents and the dry matter weight ratio of said thickening agents upon the glue is preferably between 1 and 4 wt%, preferably between 2 and 3 wt%, for example 2,5 wt%;

[0098] -the glue comprises surfactants and the dry matter weight surfactants upon the glue is preferably between 1 and 4 wt% of said surfactants, preferably between 2 and 3 wt%, for example 2,5 wt%.

[0099] -the glue comprises acrylates and the dry matter weight glue comprises between 2 and 15 wt% of acrylates, for example 5 wt% or 10 wt%.

[0100] According to second variants of the first and / or second and / or third and / or fourth and / or fifth and / or sixth and / or seventh and / or eight and / or ninth aspect of the invention, said second component is optional. Here the glue, upon curing, will have a less dense network. For some embodiments, this can be preferred. Said additional features of above- mentioned first and / or second and / or third and / or fourth and / or fifth and / or sixth and / or seventh and / or eight and / or ninth aspect of the invention, are also beneficial for a glue which does not make use of said second component. For example the aldehydes will also enhance crosslinking. The wetting agents will enhance wetting of the lignocellulosic material. The viscosity reducing agents will improve the pumpability of the glue. The metal complexes will enhance the crosslinking during curing of the glue. Said phosphates will also enhance the crosslinking. Said thickening agents can provide the glue with the desired viscosity. Said surfactants can enhance the ease of application of the glue. The acrylates will enhance crosslinking of the glue.

[0101] For said above-mentioned second variants, one or more of the following features are preferably present:

[0102] -the glue comprises aldehydes and the dry matter weight ratio of the aldehydes upon the glue is between 0,05 and 1,5 wt%;

[0103] -the glue comprises wetting agents and the dry matter weight ratio of the wetting agents upon the glue is between 0,05 and 1,5 wt%;

[0104] -the glue comprises viscosity reducing agents and the dry matter weight ratio of the viscosity reducing agents upon the glue is between 0,05 and 1,5 wt%;

[0105] -the glue comprises phosphates and the dry matter weight ratio of said phosphates upon said glue is preferably between 0,05 and 1,5 wt%;

[0106] -the glue comprises thickening agents and the dry matter weight ratio of said thickening agents upon the glue is preferably between 1 and 4 wt%, preferably between 2 and 3 wt%, for example 2,5 wt%;

[0107] -the glue comprises surfactants and the dry matter weight surfactants upon the glue is preferably between 1 and 4 wt% of said surfactants, preferably between 2 and 3 wt%, for example 2,5 wt%.

[0108] -the glue comprises acrylates and the dry matter weight glue comprises between 2 and 15 wt% of acrylates, for example 5 wt% or 10 wt%.

[0109] The invention, according to a tenth aspect, relates to a method for producing a glue, preferably a glue for cellulosic material, wherein materials of said glue are provided, said materials at least comprising a first material comprising amine functional groups, for example comprising amines and / or amides, a second material comprising amine functional groups, for example comprising amines and / or amides, and a third material comprising carbohydrates, with said first material and said second material having or not having substantially the same composition; and wherein the method at least comprises the following steps:

[0110] -forming a first component by at least reacting the third material with the first material, said carbohydrates of the third material comprising reducing sugars and / or comprising non-reducing sugars which are invertable, such that the first component comprises a prereacted composition with reaction products of the first material and reducing sugars;

[0111] -adding a second component to the first component, said second component comprising the second material; wherein the materials further comprise one or more additives chosen from the list of: -aldehydes, for example chosen from the list of: glyoxal, glutaraldehyde, succinaldehyde and malondialdehyde;

[0112] - wetting agents, for example chosen from the list of: glycerol, sulphates -such as sodium lauryl sulphate-, propylene glycol;

[0113] -metal complexes, for example chosen from the list of: Zn(OAc)2, Mg(0H)2, Ca(OH)2, titanium acrylates, organozirconium compounds, ferric sulphate;

[0114] -bases, for example potassium carbonate (K2CO3);

[0115] -viscosity reducing agents, for example chosen from the list of: amino acids, sulphites, sulphates and sulphonates;

[0116] -phosphates, such as di sodium hydrogen phosphate;

[0117] -thickening agents, wherein said thickening agents are preferably carboxymethyl cellulose and / or gum;

[0118] -surfactants, preferably chosen from the list of: soaps, detergents, salts and alcohols;

[0119] -acrylates, wherein said acrylates are preferably diacrylates, triacrylates or multi acrylates.

[0120] With this method a glue according to the first aspect can be made. Said additives then at least comprise aldehydes. Also with this method a glue according to the second aspect can be made. Said additives then at least comprise wetting agents. This method is also suitable to make a glue according to the third aspect. Then said additives at least comprise metal complexes. With this method a glue according to the fourth aspect can be made. Then the additives preferably comprise bases. It is also possible to make a glue according to the fifth aspect with this method. Then the additives at least comprise viscosity reducing agents. With this method a glue according to the sixth aspect can be made. Then the additives at least comprise phosphates. With this method a glue according to the seventh aspect can be made. Then the additives at least comprise thickening agents. With this method a glue according to the eight aspect can be made. Then the additives at least comprise surfactants. Also with this method a glue according to the ninth aspect can be made. Then the additives at least comprise acrylates.

[0121] This method is thus suitable for forming a glue according to the first and / or second and / or third and / or fourth and / or fifth and / or sixth and / or seventh and / or eight and / or ninth aspect of the invention. All the benefits and / or specific features of said glues according to the first and / or second and / or third and / or fourth and / or fifth and / or sixth and / or seventh and / or eight and / or ninth aspect of the invention, thus apply mutatis mutandis for the tenth aspect of the invention and vice versa.

[0122] The following combinations of additives are very preferred embodiments:

[0123] 1) aldehydes, preferably glyoxal, and wetting agents, preferably glycerol;

[0124] 2) aldehydes, preferably glyoxal, and viscosity reducing agents, preferably amino acids;

[0125] 3) wetting agents and metal complexes;

[0126] 4) viscosity reducing agents and metal complexes;

[0127] 5) bases and aldehydes, preferably glyoxal;

[0128] 6) aldehydes, preferably glyoxal, and wetting agents, preferably glycerol, and bases;

[0129] 7) aldehydes, preferably glyoxal, and viscosity reducing agents, preferably amino acids, and bases;

[0130] 8) aldehydes, preferably glyoxal, and wetting agents, preferably glycerol, and metal complexes and optionally bases;

[0131] 9) aldehydes, preferably glyoxal, and viscosity reducing agents, preferably amino acids, and metal complexes and optionally bases;

[0132] 10) aldehydes, preferably glyoxal, and phosphates;

[0133] 11) all the abovementioned additives, except that if use is made of viscosity reducing agents, preferably no use is made of thickening agents and vice versa; 12) acrylates and wetting agents;

[0134] 13) thickening agents and surfactants;

[0135] 14) aldehydes, preferably glyoxal, and acrylates and wetting agents.

[0136] By having already said reaction products, said glue can be cured in a faster manner and / or less of the second material is needed to obtain board material and / or laminates.

[0137] Among others, said aldehydes enhance crosslinking of the glue. Said wetting agents and / or viscosity reducing agents enhance the wetting abilities of the glue such that the glue can be more easily homogeneously spread upon the lignocellulosic material. Said metal complexes and / or said phosphates enhance crosslinking. Said bases can ensure that the first component and the second component have a similar acidity, such that they are well mixable and form a stable glue. Said acrylates enhance crosslinking. Further benefits / embodiments are described in the abovementioned aspects of glues according to the invention.

[0138] In a very preferred embodiment at least one of said one or more additives is added when forming the first component, preferably is added in a dry matter weight ratio upon said pre-reacted composition of between 0,1 and 2 wt%. The result is a first component comprising at least one of said one or more additives. For example the result is a first component comprising said pre-reacted composition and further aldehydes and / or wetting agents and / or bases and / or said viscosity reducing. For example the result is a first component further comprising aldehydes and wetting agents, or further comprising aldehydes and viscosity reducing agents. Said first component and said second component can be stored separately and have a good shelf life.

[0139] Further preferably, said at least one of said one or more additives which is added when forming the first component, is added after forming said pre-reacted composition, and wherein preferably said pre-reacted composition is substantially free from unreacted amine functional groups. This way undesired curing of the glue, before said glue is being used for (ligno)cellulosic material, is avoided. For example, first said first material and said third material are added together and preferably heated to start the reaction between reducing sugars and the amine functional groups. The result is, among others, Maillard reaction products. Then said pre-reacted composition is optionally cooled down. Then said at least one of said one or more additives is added to the pre-reacted composition. If different types of additives are present in the first component, these can be all added at the same time or they can added separately. The result is then the first component, said first component comprising the pre-reacted composition and the said additives. To glue said (ligno)cellulosic material, the first component and the second component are preferably added together and then applied to the (ligno)cellulosic material.

[0140] In a very preferred embodiment,

[0141] -the third material comprises at least 90 wt% of reducing sugars, preferably at least 95 wt%, more preferably at least 99 wt%, wherein said third material is for example invert sugar, or

[0142] -the third material comprises non-reducing sugars which are converted into reducing sugars before or during forming of the pre-reacted composition, for example the third material is sucrose which is inverted with the aid of acids, wherein preferably at least 95 wt% of the non-reducing sugars are inverted, preferably at least 99 wt%.

[0143] If the third material comprises or is non-reducing sugars, such as sucrose, then preferably acids or enzymes are added to said third material, before adding said third material to the first material. In this manner reducing sugars are already present when adding said first and said third material together, such that the formation of said reaction products can be done a good manner.

[0144] In a very preferred embodiment the difference in acidity / alkalinity (pH) of the first component and the second component, is at most 1 pH, preferably at most 0,5 pH, most preferably at most 0,2 pH and wherein preferably the acidity of the first component is adapted to the acidity of the second component by adding bases when forming the first component. For example the second material can be a water-based dispersion / solution of hyperbranched polyamides, such as hyperbranched polylysine, obtained by polymerisation of amino acids, for example amino acids chosen from the list of lysine, arginine, glutamine and histidine. Such second material is typically slightly alkaline, for example has a pH of between 9 and 11, such as 9,2 or 9,8 or 10,2. The first component can comprise a pre-reacted composition comprising reaction products between the first material and the third material, said first material being similar to the second material and said third material comprising glucose and / or fructose. Such a pre-reacted composition is typically slightly acid. By adding bases to form said first component, said first component can have an acidity similar to the acidity of the second component. If said first and second component have a similar acidity, then these can be mixed and remain stable, e.g. have a good shelf life, for at least 6h, preferably at least 12h, more preferably at least 24h.

[0145] Preferably, the dry matter weight ratio of the first material upon the dry matter weight of the third material, is between 4 and 30 wt%, preferably being between 5 and 25 wt%, is for example 6 wt% or 9 wt%.

[0146] Preferably, for the glue, the weight ratio of the dry matter weight of the third material upon the dry matter weight of the first and second material, is between 50:50 and 80:20, preferably between 60:40 and 70:30.

[0147] In a very preferred embodiment, the dry matter weight ratio of the first material upon the dry matter weight of the third material, is between 4 and 30 wt%, preferably being between 5 and 25 wt%, is for example 6 wt% or 9 wt%, and the weight ratio of the dry matter weight of the third material upon the dry matter weight of the first and second material, is between 50:50 and 80:20, preferably between 60:40 and 70:30. It has been found that with such composition the glue, upon curing, can form a very dense and strong network. The more of said second material is present, the stronger the glue. For example if said glue is used for forming a resin-treated sheet that is provided to be attached to a wood based substrate by lamination by heat and pressure, than one can choose for a less dense network, for example a weight ratio of the dry matter weight of the third material upon the dry matter weight of the first and second material, of between 70:30 and 80:20, such that the resin has sufficient time to flow deeply into the wood based substrate during said lamination, e.g. during the curing of said resin. The invention, according to an eleventh aspect, relates to a board material comprising plant particles, such as vegetable fibres and / or wood chips and / or wood pieces, and a cured glue that bonds these plant particles to one another, wherein the cured glue is obtained by curing a glue according to the first aspect and / or the second aspect and / or the third aspect and / or the fourth aspect and / or the fifth aspect and / or the sixth aspect and / or seventh aspect and / or eight aspect and / or ninth aspect, and / or is obtained by curing a glue made by a method according to the tenth aspect.

[0148] According to a first variant of the eleventh aspect, said plant particles can be completely or at least partially replaced by alternative particles, for example particles which are less prone to swelling, for example ceramic particles, plastic particles or metallic particles. For example the weight ratio alternative particles:plant particles can be between 1 :2 and 1 :20, for example can be 1 :4 or 1:8 or 1 : 12. A first example of such a first variant, is a board material wherein all the plant particles are replaced by a mineral, for example by mineral fibers. Said mineral can be magnesium oxide. A second example of such a first variant, is a board material wherein the plant particles are partially replaced by a mineral, for example by mineral fibers. Said board material can comprise a combination of magnesium oxide and wood fibers, with the weight ratio MgO:wood fibers is for example between 30:70 and 50:50, such as between 35:65 and 45:55.

[0149] According to a twelfth aspect, the invention relates to a laminate comprising at least two sheets and at least a cured resin to bond said sheets to each other, wherein the cured resin is obtained by curing a glue according to the first aspect and / or the second aspect and / or the third aspect and / or the fourth aspect and / or the fifth aspect and / or the sixth aspect and / or the seventh aspect and / or the eight aspect and / or the ninth aspect, and / or is obtained by curing a glue made by a method according to the tenth aspect. Said sheets can be chosen from the list of: paper, cardboard, textile and glass fiber sheets.

[0150] The invention, according to the thirteenth aspect, also relates to a resin-treated sheet comprising a sheet comprising a resin / glue according to the first aspect and / or the second aspect and / or the third aspect and / or the fourth aspect and / or the fifth aspect and / or the sixth aspect and / or the seventh aspect and / or the eight aspect and / or the ninth aspect, and / or is obtained by curing a glue made by a method according to the tenth aspect. Said resin-treated sheet can be resin-impregnated sheet and / or a resin-coated sheet. Said sheet can be chosen from the list of: paper, cardboard, textile and glass fiber sheets.

[0151] For all the abovementioned aspects, the cellulosic material can be paper and / or can be plant particles. Plant particles, such as for example wood chips, wood shavings, wood layers, wood fibres or other vegetable fibres, are provided with a said glue according to the invention, i.e. glued, by for example atomizing / spraying / pouring glue onto these plant particles. For this purpose, the plant particles can be located in an air flow or a mixer in order to glue the plant particles as homogeneously as possible by means of atomization and / or mechanical friction. After this, the glued plant particles are pressed together, for example in a continuous press or a discontinuous press, under a specified pressure, for example a pressure of between 2 and 6 N / mm2, preferably between 2 and 4 N / mm2, at a specified temperature, for example a temperature of between 160°C and 245°C, preferably between 200°C and 245°C, and for a specified time, for example at least 4 sec per mm of board thickness. The glue will bond to the plant particles and undergo curing in order to obtain a solid board. If the cellulosic material is a paper, said glue can also be indicated as a resin. A said paper can be impregnated and / or coated with said resin.

[0152] The invention also relates to a glue made by combining reducing sugars with at least a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides, wherein said glue comprises thickening agents, wherein said thickening agents are preferably carboxymethyl cellulose and / or gum. By using thickening agents, said glue can have the desired viscosity, e.g. a sufficient high viscosity. For certain applications, it is desired that glue has a higher viscosity, for example a viscosity of at least 20 mPa.s, at 20°C and 1.013 bar, preferably at least 40 mPa s, more preferably at least 50 mPa s, more preferably at least 100 mPa s, more preferably at least 500 mPa s, more preferably at least 1000 mPa s, most preferably at least 2000 mPa s. The latter is beneficial if the glue is used as a so-called wood glue to glue wood containing objects to each other, or to glue a HPL to a substrate such as particle board substrate or a wood fiberboard substrate. If such glue is used to glue a HPL to a said substrate, said substrate can comprise a glue according to another aspect as described in this application and also said HPL can comprise a glue according to another aspect described in this application. As such it is possible to use only or substantially biobased glues for wood based panels, for example for furniture.

[0153] Preferably, the dry matter weight glue comprises between 1 and 4 wt% of said thickening agents, preferably between 2 and 3 wt%, for example 2,5 wt%.

[0154] Said glue can or cannot be a glue comprising at least two components, said two components for example being

[0155] -a first component which comprises a pre-reacted composition with at least reaction products of reducing sugars with a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides;

[0156] -a second component comprising a second material, said second material comprising amine functional groups, for example said second material comprising amines and / or amides; wherein said thickening agents form part of said first component and / or second component, or wherein said thickening agents form a third component. Such a glue is a glue according to the seventh aspect of the invention.

[0157] Said amines and / or amides can be amines and / or amides such as indicated in previous aspects. Said reducing sugars can be reducing sugars as indicated in previous aspects.

[0158] The invention also relates to a glue made by combining reducing sugars with at least a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides, wherein said glue comprises surfactants, preferably chosen from the list of: soaps, detergents, salts and alcohols. By using surfactants, said glue forms a nice film when being applied. For certain applications, it is desired that the glue can easily be evenly applied. The latter is beneficial if the glue is used as a so-called wood glue to glue wood containing objects to each other, or to glue a HPL to a substrate such as particle board substrate or a wood fiberboard substrate. If such glue is used to glue a HPL to a said substrate, said substrate can comprise a glue according to another aspect as described in this application and also said HPL can comprise a glue according to another aspect described in this application. As such it is possible to use only or substantially bio-based glues for wood based panels, for example for furniture. Preferably said glue also comprises a said thickening agent.

[0159] Preferably, the dry matter weight glue comprises between 1 and 4 wt% of said surfactants, preferably between 2 and 3 wt%, for example 2,5 wt%.

[0160] Said glue can or cannot be a glue comprising at least two components, said two components for example being

[0161] -a first component which comprises a pre-reacted composition with at least reaction products of reducing sugars with a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides;

[0162] -a second component comprising a second material, said second material comprising amine functional groups, for example said second material comprising amines and / or amides; wherein said surfactants form part of said first component and / or second component, or wherein said surfactants form a third component. Such a glue is a glue according to the eighth aspect of the invention.

[0163] Said amines and / or amides can be amines and / or amides such as indicated in previous aspects. Said reducing sugars can be reducing sugars as indicated in previous aspects.

[0164] The invention also relates to a method to attach to a first and a second object to each other, wherein at least said first object comprises wood components, wherein a glue comprising a said thickening agent and / or a said surfactant as described above is used, wherein preferably said first object and second object are respectively:

[0165] -a wood-based board and a high pressure laminate (HPL);

[0166] -a first wood-based panel and a second wood-based panel;

[0167] -a first wooden panel and a second wooden panel. Preferably said first object is a wood-based board, such as a particle board or a wood fiber board, and wherein said second object is a HPL, wherein said HPL is glued to a surface or to an edge of said wood-based board panel with said glue, wherein before glueing said HPL to said wood-based board, a primer is applied to said surface or edge, wherein said primer preferably has a different composition than said glue. This primer ensures that a sufficient thick glue layer can be formed upon the wood-based board, such that sufficient glue is present to attach the HPL to the wood-based panel. Alternatively, said glue can be applied to the HPL, after which the HPL is attached to the wood-based board. The use of a primer becomes redundant since the glue can more easily form a nice glue layer upon the HPL. Also alternatively, said glue can firstly be applied upon the wood-based board and cured, after which a layer of said glue can be further applied upon the wood-based board. By first curing said firstly applied glue, it is ensured that a sufficient thick layer of glue can be formed upon the wood-based board to attach the HPL to the wood-based board.

[0168] The invention, according to the fourteenth aspect, also relates to a glue made by combining reducing sugars with at least a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides, wherein said glue comprises acrylates, wherein said acrylates are preferably diacrylates, triacrylates or multi acrylates. Examples of possible acrylates are diacrylates, triacrylates or multi acrylates, this being molecules with two acrylate side chains, three acrylate side chains or more acrylate side chains. This acrylates can be small molecules, such as for example an aromatic with acrylate side chains, or an oligomer with acrylate side chains or a polymer with acrylate side chains. Such acrylates can take up between 3 and 15 wt% of the total dry matter weight of the glue, for example 5 wt% or 10 wt%. Surprisingly it was found that acrylates are excellent crosslinkers for said glue, such that curing of said glue can be accelerated and strong materials are obtained, for example strong laminates or strong wood-based boards. Said acrylates are also homogeneously spread in said glue, such that said acrylates can well perform its crosslinking function during curing of said glue. Said amines and / or amides can be amines and / or amides such as indicated in previous aspects. Said reducing sugars can be reducing sugars as indicated in previous aspects.

[0169] The invention also relates to the following list of items:

[0170] 1.- A glue for cellulosic material, wherein said glue is made by combining reducing sugars with a least a first material, said first material comprising amine functional groups, such as polyamides obtained by polymerization of amino acids, characterized in that said glue comprises aldehydes, wherein the dry matter weight ratio of the aldehydes upon said sugars and first material is preferably between 0,1 and 3 wt%.

[0171] 2.- The glue according to item 1, wherein said first material at least comprises amides, wherein said amides comprise, and preferably are, polyamides obtained by polymerization of amino acids, and wherein more preferably the polyamides are or comprise hyperbranched polyamides. The amides can be (hyperbranched) polylysine.

[0172] 3.- The glue according to any of the preceding items, wherein the reducing sugars comprise glucose and / or fructose, and preferably are a mixture of glucose and fructose.

[0173] 4.- The glue according to any of the preceding items, wherein the aldehydes are chosen from the list of: glyoxal, glutaraldehyde, succinaldehyde, malondialdehyde.

[0174] 5.- The glue according to any of the preceding items 2 to 5, wherein the weight ratio of reducing sugars upon amides is between 50:50 and 80:20, preferably between 60:40 and 70:30.

[0175] 6.- A glue for cellulosic material, optionally according to any of the preceding items 1 to 5, wherein said glue is made by combining reducing sugars with a least a first material, said first material comprising amine functional groups, such as polyamides obtained by polymerization of amino acids, characterized in that said glue comprises wetting agents, wherein the dry matter weight ratio of the wetting agents upon said reducing sugars and first material is preferably between 0,1 and 2 wt%. 7. - The glue according to item 6, wherein the wetting agents are chosen from the list of: glycerol, sulphates -such as sodium lauryl sulphate-, propylene glycol.

[0176] 8.- The glue according to item 6 or 7, wherein said first material at least comprises amides, wherein said amides comprise, and preferably are, polyamides obtained by polymerization of amino acids, and wherein more preferably the polyamides are hyperbranched polyamides. The amides can be (hyperbranched) polylysine.

[0177] 9.- The glue according to any of the preceding items 6 to 8, wherein the reducing sugars comprise glucose and / or fructose, and preferably are a mixture of glucose and fructose.

[0178] 10.- The glue according to any of the preceding items 7 to 9, wherein the weight ratio of reducing sugars upon amides is between 50:50 and 80:20, preferably between 60:40 and 70:30.

[0179] 11.- A glue for cellulosic material, optionally according to any of the preceding items 1 to 10, wherein said glue is made by combining reducing sugars with a least a first material, said first material comprising amine functional groups, such as polyamides obtained by polymerization of amino acids, characterized in that said glue comprises metal complexes, wherein the weight ratio of the dry matter weight metal complexes upon the dry matter weight reducing sugars and first material is preferably between 0,1 and 2 wt%, and wherein preferably the metal complexes are chosen from the list: Zn(OAc)2, Mg(OH)2, Ca(OH)2, titanium acrylates, organozirconium compounds, ferric sulphate.

[0180] 12.- The glue according to item 11, wherein said first material at least comprises amides and, wherein said amides comprise, and preferably are, polyamides obtained by polymerization of amino acids, and wherein more preferably the polyamides are hyperbranched polyamides. The amides can be (hyperbranched) polylysine. 13.- The glue according to any of the preceding items 11 to 12, wherein the reducing sugars comprise glucose and / or fructose, and preferably are a mixture of glucose and fructose.

[0181] 14.- The glue according to any of the preceding items 12 to 13, wherein the weight ratio of reducing sugars upon amides is between 50:50 and 80:20, preferably between 60:40 and 70:30.

[0182] 15.- A glue for cellulosic material, optionally according to any of the preceding items 1 to 14, wherein said glue is made by combining reducing sugars with a least a first material, said first material comprising amine functional groups, such as polyamides obtained by polymerization of amino acids, characterized in that said glue comprises viscosity reducing agents, wherein the dry matter weight ratio of the viscosity reducing agents upon the reducing sugars and the first material is preferably between 0,1 and 2 wt%.

[0183] 16.- The glue according to item 15, wherein the viscosity reducing agents are chosen from the list of: amino acids, sulphites, sulphates and sulphonates.

[0184] 17.- The glue according to any of the preceding items 15 to 16, wherein said first material at least comprises amides, wherein said amides comprise, and preferably are, polyamides obtained by polymerization of amino acids, and wherein more preferably the polyamides are hyperbranched polyamides. The amides can be (hyperbranched) polylysine.

[0185] 18.- The glue according to any of the preceding items 15 to 17, wherein the reducing sugars comprise glucose and / or fructose, and preferably are a mixture of glucose and fructose.

[0186] 19.- The glue according to any of the preceding items 16 to 18, wherein the weight ratio of reducing sugars upon amides is between 50:50 and 80:20, preferably between 60:40 and 70:30. 20.- A glue for cellulosic material, optionally according to any of the preceding items 1 to 19, wherein said glue is made by combining reducing sugars with a least a first material, said first material comprising amine functional groups, such as polyamides obtained by polymerization of amino acids, characterized in that said glue comprises phosphates, wherein the dry matter weight ratio of said phosphates upon reducing sugars and first material is preferably between 0,1 and 2 wt%.

[0187] 21.- The glue according to item 20, wherein said first material at least comprises amides, wherein said amides comprise, and preferably are, polyamides obtained by polymerization of amino acids, and wherein more preferably the polyamides are hyperbranched polyamides. The amides can be (hyperbranched) polylysine.

[0188] 22.- The glue according to item 20 or 21, wherein the reducing sugars comprise glucose and / or fructose, and preferably are a mixture of glucose and fructose.

[0189] 23.- The glue according to any of the preceding items 20 to 22, wherein the phosphates are disodium hydrogen phosphate.

[0190] 24.- The glue according to any of the preceding items 21 to 23, wherein the weight ratio of reducing sugars upon amides is between 50:50 and 80:20, preferably between 60:40 and 70:30.

[0191] 25.- A glue for cellulosic material, optionally according to any of the preceding items

[0192] 1 to 24, wherein said glue comprises at least two components, being

[0193] -a first component which comprises a pre-reacted composition with at least reaction products of reducing sugars with a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides;

[0194] -a second component comprising a second material, said second material comprising amine functional groups, for example said second material comprising amines and / or amides; characterized in that said glue comprises thickening agents, wherein said thickening agents are preferably carboxymethyl cellulose and / or gum.

[0195] 26.- The glue according to item 25, wherein the dry matter weight glue comprises between 1 and 4 wt% of said thickening agents, preferably between 2 and 3 wt%, for example 2,5 wt%.

[0196] 27.- A glue for cellulosic material, optionally according to any of the preceding items

[0197] 1 to 26, wherein said glue comprises at least two components, being

[0198] -a first component which comprises a pre-reacted composition with at least reaction products of reducing sugars with a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides;

[0199] -a second component comprising a second material, said second material comprising amine functional groups, for example said second material comprising amines and / or amides; characterized in that said glue comprises surfactants, preferably chosen from the list of: soaps, detergents, salts and alcohols.

[0200] 28.- The glue according to item 27, wherein the dry matter weight glue comprises between 1 and 4 wt% of said surfactants, preferably between 2 and 3 wt%, for example 2,5 wt%.

[0201] 29.- A glue for cellulosic material, optionally according to any of the preceding items

[0202] 1 to 28, wherein said glue comprises at least two components, being

[0203] -a first component which comprises a pre-reacted composition with at least reaction products of reducing sugars with a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides;

[0204] -a second component comprising a second material, said second material comprising amine functional groups, for example said second material comprising amines and / or amides; characterized in that said glue comprises acrylates, wherein said acrylates are preferably diacrylates, triacrylates or multi acrylates. 30.- The glue according to item 29, wherein the dry matter glue comprises between 2 and 15 wt% of acrylates, for example 5 wt% or 10 wt%.

[0205] 31.- The glue according to any of the preceding items, wherein instead of cellulosic material, said glue is used for insulation material.

[0206] Instead of cellulosic material, said glues according to the invention can be used for insulation materials, such as glass wool, rock wool, etc.

[0207] In order to better explain the features of the invention, several preferred embodiments are described below as examples that by no means limit the scope of the invention.

[0208] To demonstrate beneficial features of said embodiments, several tests were performed.

[0209] Test series 1

[0210] Test series 1 was performed to illustrate the effect of wetting agents and the effect of viscosity reducing agents.

[0211] To have a reference board material, firstly a reference glue was made with the following raw materials: invert sugar and a dispersion of hyperbranched polylysine. Said glue was made with the following ratios of said raw materials, namely the ratio of invert sugar to dry matter weight hyperbranched polylysine was 61 :39. Said glue was made as follows: -a first component was made by adding the invert sugar to a part of the dispersion of the hyperbranched polylysine, namely in a ratio of dry matter weight polylysine to invert sugar of 6:100. Then heating was performed to form a said pre-reacted composition comprising Maillard reaction products resulting from the reaction between said reducing sugars and said hyperbranched polylysine;

[0212] -to form said glue, the rest of said dispersion of hyperbranched polylysine was added to the first component, as such forming said glue. This reference glue was provided upon wood chips to form a cake and said cake was pressed in a pressing device to form a particle board material.

[0213] Further, glues according to the invention were made and said glues were provided upon wood chips to form cakes which were pressed in a pressing device to form particle board material.

[0214] For the above, the same raw materials, e.g. the invert sugar, the dispersion of hyperbranched polylysine were used. Further similar conditions, e.g. the heating to form the pre-reacted composition, the ratios of dry matter weight polylysine to invert sugar, the pressing conditions, etc. were used such to be able to compare said glues according to the invention to the reference glue.

[0215] A first example of such glue according to the invention was made as follows:

[0216] -a first component was made by adding the invert sugar to a part of the dispersion of the hyperbranched polylysine, namely in a ratio of dry matter weight polylysine to invert sugar of 6:100. Then heating was performed to form a said pre-reacted composition comprising Maillard reaction products resulting from the reaction between said reducing sugars and said hyperbranched polylysine. Said pre-reacted composition was cooled and based upon the dry matter weight of invert sugar and hyperbranched polylysine which formed said pre-reacted composition, 0,5 wt% of monomer L-lysine was added, as such forming the first component. L-lysine reduces the viscosity of said first component;

[0217] -to form said glue, the rest of said dispersion of hyperbranched polylysine was added to the first component, as such forming said glue.

[0218] A second example of a glue according to the invention was made as follows:

[0219] -a first component was made by adding the invert sugar to a part of the dispersion of the hyperbranched polylysine, namely in a ratio of dry matter weight polylysine to invert sugar of 6:100. Then heating was performed to form a said pre-reacted composition comprising Maillard reaction products resulting from the reaction between said reducing sugars and said hyperbranched polylysine. Said pre-reacted composition was cooled and based upon the dry matter weight of invert sugar and hyperbranched polylysine which formed said pre-reacted composition, 1 wt% of glycerol was added, as such forming the first component;

[0220] -to form said glue, the rest of said dispersion of hyperbranched polylysine was added to the first component, as such forming said glue.

[0221] It was observed that the with abovementioned examples of glues according to the invention, a more coherent cake was formed, which could be pressed in a better manner, resulting in particle board material with improved characteristics, in comparison with a cake made with the reference glue.

[0222] Test series 2

[0223] Test series 2 was performed to illustrate the effect of a first component and a second component having approximately the same the acidity.

[0224] The same reference glue as in test 1 was made. Also the same invert sugar and the same dispersion of hyperbranched polylysine was used, with the same ratio’s. Said first component of said reference glue has a pH of 7,5.

[0225] Said dispersion of hyperbranched polylysine has a pH of 9,8, such that the second component has an acidity of 9,8 pH.

[0226] An example of a glue according to the invention was made as follows:

[0227] -a first component was made by adding the invert sugar to a part of the dispersion of the hyperbranched polylysine, namely in a ratio of dry matter weight polylysine to invert sugar of 6:100. Then heating was performed to form a said pre-reacted composition comprising Maillard reaction products resulting from the reaction between said reducing sugars and said hyperbranched polylysine. Said pre-reacted composition was cooled and had a pH of 7,5. K2CO3 was added until a pH of 9,2 was reached;

[0228] -to form said glue, the rest of said dispersion of hyperbranched polylysine was added to the first component, as such forming said glue. It was observed that mixing of the first component and the second component to form said glue according to the invention, was easier and required less shear than mixing of the first component and the second component to form the reference glue. Further said glue according to the invention had a longer shelf life than the reference glue.

[0229] Test series 3

[0230] Test series 3 was performed to illustrate the effect of the amount of aldehydes.

[0231] Different types of glues were tested of which 4 are discussed in more detail below:

[0232] Said 4 glues were made with invert sugar and with a dispersion comprising hyperbranched polylysine (HBPL) as used in the abovementioned test. Also the same ratios were used for said invert sugar and hyperbranched polylysine. Further K2CO3, an epoxide (tri-oxirane) and glycerol / glyoxal was used to form said glues.

[0233] Said glues were made as follows:

[0234] -a first component was made by adding the invert sugar to a part of the dispersion of the hyperbranched polylysine, namely in a ratio of dry matter weight polylysine to invert sugar of 6:100. Then heating was performed to form a said pre-reacted composition comprising Maillard reaction products resulting from the reaction between said reducing sugars and said hyperbranched polylysine. Said pre-reacted composition was cooled and K2CO3, an epoxide and glycerol / glyoxal was added, to form said first component;

[0235] -to form said glue, the rest of said dispersion of hyperbranched polylysine was added to the first component, as such forming said glue.

[0236] These glues were provided upon wood chips to form a cake and said cake was pressed in a pressing device to form a particle board material. Similar pressing conditions were used and similar wood chips.

[0237] For said glues, different amounts of glycerol and / or glyoxal were used, resulting in the following: wt% are upon dry matter weight invert sugar and all HBPL unless otherwise indicated. The transverse tensile strength is in accordance with E319.

[0238] The bending strength is in accordance with EN 310.

[0239] The modulus of elasticity is in accordance with EN 310.

[0240] With the aid of glyoxal, a higher tensile strength could be obtained.

[0241] Observations when performing said third series of test could be summarized as follows: -with glyoxal pressing times could be reduced;

[0242] -the obtained board material could have better technical characteristics;

[0243] -with glyoxal a good coherent cake can be formed, even when no glycerol is used.

[0244] Test series 4

[0245] Test series 4 was performed to illustrate the effect of the amount of phosphates.

[0246] Different types of glues were tested of which 4 are discussed in more detail below:

[0247] Said 4 glues were made with invert sugar and with a dispersion comprising hyperbranched polylysine (HBPL) as used in the abovementioned test. Also the same ratios were used for said invert sugar and hyperbranched polylysine. Further K2CO3, an epoxide (tri-oxirane), glycerol / di sodium hydrogen phosphate was used to form said glues.

[0248] Said glues were made as follows:

[0249] -a first component was made by adding the invert sugar to a part of the dispersion of the hyperbranched polylysine, namely in a ratio of dry matter weight polylysine to invert sugar of 6:100. Then heating was performed to form a said pre-reacted composition comprising Maillard reaction products resulting from the reaction between said reducing sugars and said hyperbranched polylysine. Said pre-reacted composition was cooled and K2CO3, an epoxide and glycerol / disodium hydrogen phosphate was added, to form said first component; -to form said glue, the rest of said dispersion of hyperbranched polylysine was added to the first component, as such forming said glue.

[0250] These glues were provided upon wood chips to form a cake and said cake was pressed in a pressing device to form a particle board material. Similar pressing conditions were used and similar wood chips.

[0251] For said glues, different amounts of disodium hydrogen phosphate were used, resulting in the following: wt% are upon dry matter weight invert sugar and all HBPL unless otherwise indicated

[0252] The transverse tensile strength is in accordance with E319.

[0253] The bending strength is in accordance with EN 310.

[0254] The modulus of elasticity is in accordance with EN 310. Observations when performing said fourth series of tests could be summarized as follows: crosslinking of the glue is improved when using disodium hydrogen phosphate. Test series 5

[0255] Test series 5 was performed to illustrate the effect of the amount of acrylates.

[0256] Different types of glues were tested of which 2 are discussed in more detail below:

[0257] Said 2 glues were made with invert sugar and with a dispersion comprising hyperbranched polylysine (HBPL) as used in the abovementioned test. Also the same ratios were used for said invert sugar and hyperbranched polylysine. Further K2CO3, an acrylate and glyoxal was used to form said glues. The acrylate is an unsaturated polyester acrylate with free di- and tri-acrylates.

[0258] Said glues were made as follows:

[0259] -a first component was made by adding the invert sugar to a part of the dispersion of the hyperbranched polylysine, namely in a ratio of dry matter weight polylysine to invert sugar of 6:100. Then heating was performed to form a said pre-reacted composition comprising Maillard reaction products resulting from the reaction between said reducing sugars and said hyperbranched polylysine. Said pre-reacted composition was cooled and K2CO3, the acrylate and glyoxal was added, to form said first component;

[0260] -to form said glue, the rest of said dispersion of hyperbranched polylysine was added to the first component, as such forming said glue.

[0261] These glues were provided upon wood chips to form a cake and said cake was pressed in a pressing device to form a particle board material. Similar pressing conditions were used and similar wood chips.

[0262] For said glues, different amounts of acrylate were used, resulting in the following: wt% are upon dry matter weight invert sugar and all HBPL unless otherwise indicated The transverse tensile strength is in accordance with E319.

[0263] The bending strength is in accordance with EN 310.

[0264] The modulus of elasticity is in accordance with EN 310.

[0265] Observations when performing said fifth series of tests could be summarized as follows: crosslinking of the glue is improved when using acrylates.

Claims

1. Claims1.- A glue for cellulosic material, wherein said glue comprises at least two components, being-a first component which comprises a pre-reacted composition with at least reaction products of reducing sugars with a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides;-a second component comprising a second material, said second material comprising amine functional groups, for example said second material comprising amines and / or amides; characterized in that said glue comprises aldehydes, wherein the dry matter weight ratio of the aldehydes upon said reaction products is preferably between 0,1 and 3 wt%.2.- The glue according to claim 1, wherein said first material at least comprises amides and / or wherein said second material at least comprises amides, wherein said amides comprise, and preferably are, polyamides obtained by polymerization of amino acids, and wherein more preferably the polyamides comprise or consist of hyperbranched polyamides.3.- The glue according to any of the preceding claims, wherein the reducing sugars comprise glucose and / or fructose, and preferably are a mixture of glucose and fructose.4.- The glue according to any of the preceding claims, wherein the aldehydes are chosen from the list of: glyoxal, glutaraldehyde, succinaldehyde, malondialdehyde.5.- The glue according to any of the preceding claims, wherein said first material and said second material comprise amines and / or amides, and wherein preferably one, two or all the following features are present:-the first material and the second material substantially have the same composition;-for the pre-reacted composition, the dry matter weight ratio of amines and / or amines upon the reducing sugars, is between 4 and 30 wt%, preferably being between 5 and 25 wt%;-for the glue, the weight ratio of reducing sugars upon amines and / or amides is between 50:50 and 90: 10, for example between 55:45 and 80:20, preferably between 60:40 and 70:30.6.- A glue for cellulosic material, optionally according to any of the preceding claims1 to 5, wherein said glue comprises at least two components, being-a first component which comprises a pre-reacted composition with at least reaction products of reducing sugars with a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides;-a second component comprising a second material, said second material comprising amine functional groups, for example said second material comprising amines and / or amides; characterized in that said glue comprises wetting agents, wherein the dry matter weight ratio of the wetting agents upon said reaction products is preferably between 0,1 and 2 wt%.

7. - The glue according to claim 6, wherein the wetting agents are chosen from the list of: glycerol, sulphates -such as sodium lauryl sulphate-, propylene glycol.8.- The glue according to claim 6 or 7, wherein said first material at least comprises amides and / or wherein said second material at least comprises amides, wherein said amides comprise, and preferably are, polyamides obtained by polymerization of amino acids, and wherein more preferably the polyamides comprise or consist of hyperbranched polyamides.9.- The glue according to any of the preceding claims 6 to 8, wherein the reducing sugars comprise glucose and / or fructose, and preferably are a mixture of glucose and fructose.10.- The glue according to any of the preceding claims 6 to 9, wherein said first material and said second material comprise amines and / or amides, and wherein preferably one, two or all the following features are present:-the first material and the second material substantially have the same composition;-for the pre-reacted composition, the dry matter weight ratio of amines and / or amides upon the reducing sugars, is between 4 and 30 wt%, preferably being between 5 and 25 wt%;-for the glue, the weight ratio of reducing sugars upon amines and / or amides is between 50:50 and 90: 10, for example between 55:45 and 80:20, preferably between 60:40 and 70:30.11.- A glue for cellulosic material, optionally according to any of the preceding claims1 to 10, wherein said glue comprises at least two components, being-a first component which comprises a pre-reacted composition with at least reaction products of reducing sugars with a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides;-a second component comprising a second material, said second material comprising amine functional groups, for example said second material comprising amines and / or amides; characterized in that said glue comprises metal complexes, wherein the weight ratio of the dry matter weight metal complexes upon the dry matter weight glue is preferably between 0, 1 and 2 wt%, and wherein preferably the metal complexes are chosen from the list: Zn(OAc)2, Mg(OH)2, Ca(OH)2, titanium acrylates, organozirconium compounds, ferric sulphate.12.- The glue according to claim 11, wherein said first material at least comprises amides and / or wherein said second material at least comprises amides, wherein said amides comprise, and preferably are, polyamides obtained by polymerization of amino acids, and wherein more preferably the polyamides comprise or consist of hyperbranched polyamides.13.- The glue according to any of the preceding claims 11 to 12, wherein the reducing sugars comprise glucose and / or fructose, and preferably are a mixture of glucose and fructose.14.- The glue according to any of the preceding claims 11 to 13, wherein said first material and said second material comprise amines and / or amides, and wherein preferably one, two or all the following features are present:-the first material and the second material substantially have the same composition;-for the pre-reacted composition, the dry matter weight ratio of amines and / or amides upon the reducing sugars, is between 4 and 30 wt%, preferably being between 5 and 25 wt%;-for the glue, the weight ratio of reducing sugars upon amines and / or amides is between 50:50 and 90:10, for example between 55:45 and 80:20, preferably between 60:40 and 70:30.15.- A glue for cellulosic material, optionally according to any of the preceding claims1 to 14, wherein said glue comprises at least two components, being-a first component which comprises a pre-reacted composition with at least reaction products of reducing sugars with a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides;-a second component comprising a second material, said second material comprising amine functional groups, for example said second material comprising amines and / or amides; characterized in that the difference in acidity of the first component and the second component, is at most 1 pH, preferably at most 0,5 pH, most preferably at most 0,2 pH and wherein preferably the second component has a pH of between 9 and 11, more preferably of between 9,4 and 10,2.

16. The glue according to claim 15, wherein the first component comprises bases, for example potassium carbonate (K2CO3), and wherein preferably the dry matter weight ratio of bases upon said reaction products is preferably between 0,5 and 10 wt%, for example between 1 wt% and 5 wt%, for example 4 wt% or 6 wt%.17.- The glue according to any of the preceding claims 15 to 16, wherein said first material at least comprises amides and / or wherein said second material at least comprises amides, wherein said amides comprise, and preferably are, polyamides obtained by polymerization of amino acids, and wherein more preferably the polyamides comprise or consist of hyperbranched polyamides.18.- The glue according to any of the preceding claims 15 to 17, wherein the reducing sugars comprise glucose and / or fructose, and preferably are a mixture of glucose and fructose.19.- The glue according to any of the preceding claims 15 to 18, wherein said first material and said second material comprise amines and / or amides, and wherein preferably one, two or all the following features are present:-the first material and the second material substantially have the same composition;-for the pre-reacted composition, the dry matter weight ratio of amines and / or amides upon the reducing sugars, is between 4 and 30 wt%, preferably being between 5 and 25 wt%;-for the glue, the weight ratio of reducing sugars upon amines and / or amides is between 50:50 and 90:10, for example between 55:45 and 80:20, preferably between 60:40 and 70:30.20.- A glue for cellulosic material, optionally according to any of the preceding claims 1 to 19, wherein said glue comprises at least two components, being-a first component which comprises a pre-reacted with at least reaction products of reducing sugars with a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides;-a second component comprising a second material, said second material comprising amine functional groups, for example said second material comprising amines and / or amides;characterized in that said glue comprises viscosity reducing agents, wherein the dry matter weight ratio of the viscosity reducing agents upon said reaction products is preferably between 0,1 and 2 wt%.21 The glue according to claim 20, wherein the viscosity reducing agents are chosen from the list of: amino acids, sulphites, sulphates and sulphonates.22.- The glue according to any of the preceding claims 20 to 21, wherein said first material at least comprises amides and / or wherein said second material at least comprises amides, wherein said amides comprise, and preferably are, polyamides obtained by polymerization of amino acids, and wherein more preferably the polyamides comprise or consist of hyperbranched polyamides.23.- The glue according to any of the preceding claims 20 to 22, wherein the reducing sugars comprise glucose and / or fructose, and preferably are a mixture of glucose and fructose.24.- The glue according to any of the preceding claims 20 to 23, wherein said first material and said second material comprise amines and / or amides, and wherein preferably one, two or all the following features are present:-the first material and the second material substantially have the same composition;-for the pre-reacted composition, the dry matter weight ratio of amines and / or amines upon the reducing sugars, is between 4 and 30 wt%, preferably being between 5 and 25 wt%;-for the glue, the weight ratio of reducing sugars upon amines and / or amides is between 50:50 and 90:10, for example between 55:45 and 80:20, preferably between 60:40 and 70:30.25.- A glue for cellulosic material, optionally according to any of the preceding claims1 to 24, wherein said glue comprises at least two components, being-a first component which comprises a pre-reacted composition with at least reaction products of reducing sugars with a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides;-a second component comprising a second material, said second material comprising amine functional groups, for example said second material comprising amines and / or amides; characterized in that said glue comprises phosphates, wherein the dry matter weight ratio of said phosphates upon said reaction products is preferably between 0,1 and 2 wt%.26.- The glue according to claim 25, wherein said first material at least comprises amides and / or wherein said second material at least comprises amides, wherein said amides comprise, and preferably are, polyamides obtained by polymerization of amino acids, and wherein more preferably the polyamides comprise or consist of hyperbranched polyamides.27.- The glue according to claim 25 or 26, wherein the reducing sugars comprise glucose and / or fructose, and preferably are a mixture of glucose and fructose.28.- The glue according to any of the preceding claims 25 to 27, wherein the phosphates are disodium hydrogen phosphate.29.- The glue according to any of the preceding claims 25 to 28, wherein said first material and said second material comprise amines and / or amides, and wherein preferably one, two or all the following features are present:-the first material and the second material substantially have the same composition;-for the pre-reacted composition, the dry matter weight ratio of amines and / or amides upon the reducing sugars, is between 4 and 30 wt%, preferably being between 5 and 25 wt%;-for the glue, the weight ratio of reducing sugars upon amines and / or amides is between 50:50 and 90:10, for example between 55:45 and 80:20, preferably between 60:40 and 70:30.30.- A method for producing a glue, wherein materials of said glue are provided, said materials at least comprising a first material comprising amine functional groups, for example comprising amines and / or amides, a second material comprising amine functional groups, for example comprising amines and / or amides and a third material, with said first material and said second material having or not having substantially the same composition; and wherein the method at least comprises the following steps:-forming a first component by at least reacting the third material with the first material, said third material comprising reducing sugars and / or comprising non-reducing sugars which are invertable, such that said first component comprises a pre-reacted composition with reaction products of the first material and reducing sugars;-adding a second component to the first component, said second component comprising, and preferably consisting of, the second material; characterized in that the materials further comprise one or more additives chosen from the list of:-aldehydes, for example chosen from the list of: glyoxal, glutaraldehyde, succinaldehyde and malondialdehyde;-wetting agents, for example chosen from the list of: glycerol, sulphates -such as sodium lauryl sulphate-, propylene glycol;-metal complexes, for example chosen from the list of: Zn(OAc)2, Mg(OH)2, Ca(OH)2, titanium acrylates, organozirconium compounds, ferric sulphate;-bases, for example potassium carbonate (K2CO3);-viscosity reducing agents, for example chosen from the list of: amino acids, sulphites, sulphates and sulphonates;-phosphates, such as disodium hydrogen phosphate;-thickening agents, wherein said thickening agents are preferably carboxymethyl cellulose and / or gum;-surfactants, preferably chosen from the list of: soaps, detergents, salts and alcohols;-acrylates, wherein said acrylates are preferably diacrylates, triacrylates or multi acrylates.31.- The method according to claim 30, wherein at least one of said one or more additives is added when forming the first component, preferably is added in a dry matter weight ratio upon said pre-reacted composition of between 0,1 and 2 wt%.32.- The method according to claim 30 or 31, wherein said at least one of said one or more additives which is added when forming the first component, is added after forming said pre-reacted composition, and wherein preferably said pre-reacted composition is substantially free from unreacted amine functional groups.33.- The method according to any of the preceding claims 30 to 32, wherein-the third material comprises at least 90 wt% of reducing sugars, preferably at least 95 wt%, more preferably at least 99 wt%, wherein said third material is for example invert sugar; or-wherein said third material comprises non-reducing sugars which are converted into to reducing sugars before or during forming of the pre-reacted composition, for example the third material is sucrose which gets inverted with the aid of acids.34.- The method according to any of the preceding claims 30 to 33, wherein the difference in acidity of the first component and the second component, is at most 1 pH, preferably at most 0,5 pH, most preferably at most 0,2 pH and wherein preferably the acidity of the first component is adapted to the acidity of the second component by adding bases when forming the first component.35.- The method according to any of the preceding claims 30 to 34, wherein the dry matter weight ratio of the first material upon the third material, is between 4 and 30 wt%, preferably being between 5 and 25 wt%.36.- The method according to any of the preceding claims 30 to 35, wherein, for the glue, the dry matter weight ratio of the third material upon the sum of the weight of the first and second material, is between 50:50 and 90: 10, for example between 55:45 and 80:20, preferably between 60:40 and 70:30.37.- A board material comprising plant particles, such as vegetable fibres and / or wood chips and / or wood pieces, and a cured glue that bonds these plant particles to one another, characterized in that the cured glue is obtained by curing a glue according to any of the preceding claims 1 to 29 and / or is obtained by curing a glue made by a method according to any of the preceding claims 30 to 36.38.- A laminate comprising at least two sheets and at least a cured resin to bond said sheets to each other, characterized in that the cured resin is obtained by curing a glue according to any of the preceding claims 1 to 29 and / or is obtained by curing a glue made by a method according to any of the preceding claims 30 to 36.39.- A resin-treated sheet comprising a sheet and at least one resin, wherein said resin is a glue according to any of the preceding claims 1 to 29 and / or is a glue made by a method according to any of the preceding claims 30 to 36.40.- A glue for cellulosic material, optionally according to any of the preceding claims 1 to 29, wherein said glue is made by combining reducing sugars with at least a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides, characterized in that said glue comprises thickening agents, wherein said thickening agents are preferably carboxymethyl cellulose and / or gum.41.- The glue according to claim 40, wherein the dry matter weight glue comprises between 1 and 4 wt% of said thickening agents, preferably between 2 and 3 wt%, for example 2,5 wt%.42.- A glue for cellulosic material, optionally according to any of the preceding claims 1 to 29 and / or according to claim 40 and 41, wherein said glue is made by combining reducing sugars with at least a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides, characterized in that said glue comprises surfactants, preferably chosen from the list of soaps, detergents, salts and alcohols.43.- The glue according to claim 42, wherein the dry matter weight glue comprises between 1 and 4 wt% of said surfactants, preferably between 2 and 3 wt%, for example 2,5 wt%.44.- A method to attach to a first and a second object to each other, wherein at least said first object comprises wood components, wherein a glue according to any of the preceding claims 40 to 43 is used, wherein preferably said first object and second object are respectively:-a wood-based board and a high pressure laminate (HPL); or-a first wood-based panel and a second wood-based panel; or -a first wooden panel and a second wooden panel.45.- Method according to claim 44, wherein said first object is a wood-based board, such as a particle board or a wood fiber board, and wherein said second object is a HPL, wherein said HPL is glued to a surface or to an edge of said wood-based board panel with said glue, wherein before glueing said HPL to said wood-based board, a primer is applied to said surface or edge, wherein said primer preferably has a different composition than said glue.46.- A glue for cellulosic material, optionally according to any of the preceding claims 1 to 29 and / or any of the preceding claims 40 to 43, wherein said glue is made by combining reducing sugars with at least a first material, said first material comprising amine functional groups, for example said first material comprising amines and / or amides, characterized in that said glue comprises acrylates, wherein said acrylates are preferably diacrylates, triacrylates or multi acrylates.47.- The glue according to claim 46, wherein the dry matter weight glue comprises between 2 and 15 wt% of acrylates, for example 5 wt% or 10 wt%.48.- A board material comprising plant particles, such as vegetable fibres and / or wood chips and / or wood pieces, and a cured glue that bonds these plant particles to one another,characterized in that the cured glue is obtained by curing a glue according to claim 46 or 47.49.- A laminate comprising at least two sheets and at least a cured resin to bond said sheets to each other, characterized in that the cured resin is obtained by curing a glue according to claim 46 or 47.50.- A resin-treated sheet comprising a sheet and at least one resin, wherein said resin is a glue according to claim 46 or 47.

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