Glue and method for manufacturing raw materials for said glue

Abstract

Method for manufacturing a raw material of a glue, wherein said raw material comprises hyperbranched polyamides. Glue comprising said raw material and board comprising said glue and a laminate comprising said glue.

Description

[0001] Glue and method for manufacturing raw materials for said glue

[0002] This invention relates to a method for manufacturing a raw material of a glue, wherein said raw material comprises hyperbranched polyamides. Said glue therefore comprises hyperbranched polyamides. This glue can be used for bonding plant particles together, for example for bonding cellulose-containing materials, such as vegetable fibres and / or wood chips and / or wooden parts, to form boards. This invention thus also relates to a board comprising cellulose-containing materials, 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. This glue may 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 an MDF / HDF / chipboard substrate and one or more impregnated papers bonded to this substrate, or for forming an HPL (high pressure laminate) consisting of two or more bonded-together impregnated papers, or an 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. an impregnated paper, impregnated with the aforementioned glue. This glue can also be used for bonding vegetable fibers and / or glass fibers and / or other fibers together to form insulation.

[0003] This invention relates to boards comprising plant particles, for example lignocellulose particles and / or cellulose-containing 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 cellulose-containing materials can therefore for example be lignocellulose-containing materials. The boards are for example wood fibreboards, such as MDF -medium density fibreboard- and HDF -high density fibreboard-, 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 be partially or completely formed from recycled material, such as recycled lignocellulose-containing material. For example, the cellulose-containing 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.

[0004] 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 resin for impregnating papers, have been and are being sought. Also the presence of melamine and / or phenol are not desirable. A known formaldehyde-free glue for use in the production of wood based boards is composed of polymeric methylene diphenyl di-isocyanate (pMDI). The handling of this type of glue demands particular personal protection, due to the possible release of isocyanate monomers. An additional drawback is that this glue is based on fossil raw materials.

[0005] 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.

[0006] 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, WO 2023 / 148578 and WO 2008 / 068180. For these glues, hyperbranched polyamides are used. A drawback is the production cost, and the presence of other unwanted components in addition to said hyperbranched polyamides and / or the low uniformity of the formed hyperbranched polyamides. Said other components and / or the low uniformity can negatively influence further processing steps when forming boards comprising this glue.

[0007] The present invention concerns in the first place an alternative method for manufacturing a raw material comprising hyperbranched polyamides, wherein in accordance with various embodiments, solutions are provided for the problems with such raw material from the prior art. The present invention also concerns glues comprising said raw material, boards comprising said glues and resin impregnated sheets, such as resin impregnated papers, comprising said glues.

[0008] 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 method for manufacturing a raw material, said raw material preferably being used to form a glue, wherein said raw material comprises hyperbranched polyamides, wherein said method at least comprises the steps of

[0009] -providing a base material comprising amino acids;

[0010] -polymerizing said amino acids into hyperbranched polyamides;

[0011] -adding catalysts to promote said polymerisation of amino acids into hyperbranched polyamides; wherein said catalysts at least comprise one or more catalysts chosen from the list of Lewis acids, Lewis bases, Bronsted acids or Bronsted bases.

[0012] Such a raw material comprising hyperbranched polyamides is very suitable for manufacturing a glue, however said raw material can also be used for other applications, for example in cosmetics and / or pharmaceutical applications. Preferably said method is for manufacturing a raw material of a glue.

[0013] Said polymerisation of said amino acids into hyperbranched polyamides, can be the result of one or more of the following polymerisation reactions:

[0014] -polycondensation;

[0015] -polyaddition;

[0016] -step-growth reactions;

[0017] -cyclo-addition reactions;

[0018] -self-condensing polymerisation;

[0019] -ring-opening multibranching polymerisation;

[0020] Preferably said polymerisation is substantially a polycondensation reaction.

[0021] 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 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 (Gramnegative), 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 other amino acids, e.g. 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. Therefore a hyperbranched polylysine according to the invention does not necessarily consists of lysine. 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 comprises less of 50 weight percentage of each one of the abovementioned amino acids, said hyperbranched polyamides could be indicated as hyperbranched poly amino acids.

[0022] Said raw material of the invention is very suitable to be used for a glue that bonds plant particles together to form boards, not only for its binding capacities, but also since hyperbranched polyamides are capable of adhering to formaldehyde, for example binding it chemically via addition reactions, which allows any emission of formaldehyde from the boards to be kept extremely low. Plant particles comprise a certain amount of formaldehyde, recycled plant particles can comprise higher amounts of formaldehyde. In forming the boards, 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, among others possibly due to the resins used for the initial production of the product. The use of hyperbranched polyamides ensures that even when one works with recycled material, the emission of formaldehyde is not too high.

[0023] Surprisingly it has been found that by choosing specific catalysts, the rate of the polymerisation is not only increased, but also the formed raw material is more suitable to be used as a glue for forming boards comprising plant particles and / or for forming resin impregnated papers. For example if the catalysts comprise Lewis acids and / or Bronsted acids, said raw material preferably comprises said Lewis acids and / or Bronsted acids, and said Lewis acids and / or Bronsted acids contribute to the desired acidity of the glue. It has been found that if the catalysts comprise Lewis acids and / or Bronsted acids, said raw material is particularly useful for forming boards comprising glue with said raw material. For manufacturing said boards, a said glue is applied to plant particles, wherein said plant particles provided with said glue are pressed into a board-shaped material in order to thus form boards. It has been found that pressing conditions can be similar to pressing conditions using a ureaformaldehyde glue, meaning that production speed is not limited by said glue comprising raw material according to the invention.

[0024] By using said catalysts, the formed hyperbranched polyamides can have a sufficiently high number average molecular weight, and this while still being in a dissolved form in the raw material. Also the uniformity of said formed hyperbranched polyamides can be increased. Further the viscosity of the raw material can be controlled in a better manner. 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 the boards. 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). When the raw material is for example used to impregnate papers or other carrier layers, then the number average molecular weight can be between 1000 and 5000 g / mol.

[0025] By using said catalysts, the uniformity of said formed hyperbranched polyamides can be increased and / or the viscosity of the raw material can be controlled in a better manner.

[0026] In a preferred embodiment, said catalysts at least comprise one Lewis acid, said Lewis acid preferably being a butoxide or an acetate, such as tin butoxide or titanium butoxide or zinc acetate. With tin butoxide is preferably indicated Sn(OtBu)4. With titanium butoxide is preferably indicated Ti(OBu)4. Titanium butoxide is most preferred. The Lewis acid can also be sulphur trioxide. The Lewis acid can be added in one step, e.g. at one specific time interval, for example before polymerisation, or at the start of polymerisation, or at a specific moment / time interval during polymerisation. The Lewis acid can also be added in two or more steps, for example at two or more time intervals. For example a part of said catalysts can be added before polymerisation or at the start of polymerisation and another part of said catalysts can be added during polymerisation. Said zinc acetate can be added in the form of its dihydrate -Zn(CH3CO2)2 2H2O-. Preferably said Lewis acid is not a Bronsted acid.

[0027] In a very preferred embodiment, said catalysts at least comprise two types of Lewis acids, said Lewis acids preferably being a stronger Lewis acid, such as titanium butoxide or tin butoxide, and a weaker Lewis acid, such as zinc acetate. For example it has been found that the raw material is very suitable for a glue for bonding plant particles to form a board, when during the method firstly zinc acetate is added and at a later time during the method, titanium butoxide or tin butoxide is added. By adding titanium butoxide or tin butoxide at a later time, for example during the melt phase, it can be ensured that the formed hyperbranched polyamides have a good solubility. Further it can be ensured that no or less water is present when adding said titanium butoxide or tin butoxide, such that it can perform its function in a good manner. One of said Lewis acids can also be sulphur trioxide. Preferably at least one of said two Lewis acids is not a Bronsted acid, and more preferably both of said two Lewis acids are not Bronsted acids. If a Bronsted acid is used, then preferably this Bronsted acid is added during polymerisation, but not at the start of polymerisation, thus after a certain period / time during polymerisation.

[0028] Further preferably, a first Lewis acid of said two types of Lewis acids is added to said base material before polymerisation of said amino acids into hyperbranched polyamides or is added during polymerisation of said amino acids into hyperbranched polyamides, wherein a second Lewis acid of said two types of Lewis acids is added at a later time then said first Lewis acid and is added during polymerisation of said amino acids into hyperbranched polyamides.

[0029] In another embodiment, said catalysts at least comprise two types of catalysts, of which one is Lewis acid and of which the other is not a Lewis acid, for example is a strong base. An example is where said catalysts comprise titanium butoxide or tin butoxide and a strong base, such as potassium hydroxide. Then preferably during the method firstly titanium butoxide or tin butoxide is added and at a later time during the method the strong base is added. By adding the strong base at a later time, polymerisation can be better controlled, such that the formed hyperbranched polyamides are the desired hyperbranched polyamides and the method can be performed more uniformly, thus allowing to form a very uniform raw material. One of said Lewis acids can also be sulphur trioxide. Another example is where said catalysts comprise zin acetate and a strong base, such as potassium hydroxide. Then preferably during the method firstly zinc acetate is added and at a later time during the method the strong base is added.

[0030] In a very preferred embodiment, adding said catalysts is done in a molar ratio of catalysts upon amino acids of between 0,01% and 10%, preferably of between 0,05% and 0,1%. It has been found that said amounts not only enhance the polymerisation of amino acids into the desired hyperbranched polyamides, but that said amounts of catalysts also enhance the characteristics of the glue, e.g. enhance the curing of the glue comprising said raw material, such that said glue is very well suited for bonding plant particles into a board. Preferably said catalysts are not removed, or at least not removed completely, after said polymerisation, such that the raw material comprises said catalysts. No additional costs need to be made to remove said catalysts and / or said catalysts can also perform a catalyst function in the glue.

[0031] Preferably, adding said catalysts is done in a weight ratio of catalysts upon amino acids of between 0,015% and 15%, more preferably 0,06% and 1,5%. Adding said catalysts is preferably done in a weight ratio of catalysts upon dry weight base material of between 0,005% and 8%, more preferably between 0,07% and 1%, for example 0,15%. Said base material can comprise between 50 and 90 weight percentage of amino acids.

[0032] In a very preferred embodiment, said catalysts at least comprise catalysts comprising a metal ion. Said catalysts can be indicated as metal catalysts. The metal catalysts are preferably metal acetates and / or metal butoxides. The addition of a metal catalyst is promoting a faster polycondensation, leading to a better three-dimensional network and improving solubility of the hyperbranched polyamides, such that glues comprising said raw material have an improved performance. More preferably said catalysts are Lewis acids comprising a metal ion chosen from the list of zinc and tin and titanium, wherein most preferably said Lewis acids are not Bronsted acids.

[0033] The invention, according to a second aspect, relates to a method for manufacturing a raw material, said raw material preferably being used to form a glue, wherein said raw material comprises hyperbranched polyamides, wherein said method at least comprises the steps of:

[0034] -providing a base material comprising amino acids;

[0035] -polymerizing said amino acids into hyperbranched polyamides;

[0036] -adding crosslinkers to said base material and / or during polymerisation of said amino acids into hyperbranched polyamides; wherein said crosslinkers at least comprise one or more 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 a raw material comprising hyperbranched polyamides is very suitable for manufacturing a glue, however said raw material can also be used for other applications, for example in cosmetics and / or pharmaceutical applications. Preferably said method is for manufacturing a raw material of a glue.

[0037] Surprisingly it has been found that by using these specific type of crosslinkers, hyperbranched polyamides with the desired characteristics can be obtained. Said crosslinkers ensure polymerisation having a diverse polycondensation reaction. The crosslinkers are preferably incorporated in the formed hyperbranched polyamides during polymerisation, and said hyperbranched polyamides are well soluble, such that the formed raw material is very well suited to be used as an ingredient of a glue that is suitable for bonding plant particles together to form boards. With the aid of said crosslinkers, dense hyperbranched polyamides with an irregular structure are obtained. Said hyperbranched polyamides show high level of terminal end group functionality, such that the raw material is very reactive and suitable to use as an ingredient for a glue.

[0038] In very preferred embodiment, this second aspect of the invention is also according to the first aspect of the invention, meaning that not only said crosslinkers are added, but also said catalysts as described in the first aspect of the invention are added, e.g. catalysts such Lewis acids, Lewis bases, Bronsted acids, Bronsted bases and / or strong bases. Thus the method can also be according the first aspect of the invention and all the specific and / or preferred embodiments of this first aspect of the invention. The combination of said crosslinkers and said catalysts not only improves polymerisation of said amino acids into the desired hyperbranched polyamides, but surprisingly a glue comprising said raw material has superior properties.

[0039] In a very preferred embodiment said crosslinkers at least comprise one crosslinker with one or more alcohol end groups, said crosslinker preferably being glycerol or a polyol, such as pentaerytritol - C(CH2OH)4-. Preferably said crosslinker at least comprises three or more alcohol end groups, since more alcohol end groups ensure a better incorporation of said crosslinker into the formed hyperbranched polyamides. In a specific embodiment, said crosslinkers at least comprise one crosslinker with one or more amine end groups, such as triethanolamine (TEA) or triethylenetetramine (TETA) or tetraethylenepentamine (TEPA) or diethylenetriamine (DETA) or 4-(aminomethyl)octane-l,8-diamine (hexatran) or tri ethylamine. Preferably said crosslinker has two or more amine end groups, which ensures a good incorporation of said crosslinker into the formed hyperbranched polyamides.

[0040] In a very preferred embodiment said crosslinkers also promote branch formation. Said crosslinkers can also enhance the start of polymerisation, and can thus be indicated as starting molecules. For this, the crosslinkers preferably have 3 or more valent functional amine groups or alcohol groups or carboxyl groups. Said crosslinkers that promote branch formation are preferably trifunctional crosslinkers. During polymerisation of said amino acids into hyperbranched polyamides, these molecules ensure a strong three- dimensional network of the formed hyperbranched polyamides. This improves the solubility of the formed hyperbranched polyamides. An example is triethanolamine (TEA). For example use can be made of zinc acetate according to first aspect of the invention and TEA. TEA is preferably added before polymerisation or at the start of polymerisation, such that the amino acids, such as lysine, can start polycondensation at three places. Zinc acetate and / or a strong base can be added at the start or in a later stage of the polymerisation.

[0041] Preferably the crosslinkers are added to the base material before or at the start of polymerizing said amino acids into hyperbranched polyamides. By having said crosslinkers already at the start of polymerisation, it can be ensured that said crosslinkers are well incorporated in the formed hyperbranched polyamides, such that the hyperbranched polyamides of the raw material have the desired characteristics.

[0042] As already indicated, said method according to the second aspect of the invention is preferably also according to the first aspect of the invention. If the latter is the case, said crosslinkers are preferably at least partially added before the addition of said catalysts, more preferably wherein all of said crosslinkers are added before the addition of said catalysts, wherein more preferably the catalysts are added during polymerisation of said amino acids into hyperbranched polyamides. Polymerisation is done in controlled manner and undesirable prepolymerisation is avoided. Said catalysts can be added all at the same time, or at two or more time intervals.

[0043] Preferably the crosslinkers are incorporated into the formed hyperbranched polyamides during polymerisation of said amino acids into hyperbranched polyamides. The hyperbranched polyamides then do not consist of amino acids, but comprises at least amino acids and crosslinkers.

[0044] Adding said crosslinkers is preferably done in a molar ratio of crosslinkers upon amino acids of between 0,1% and 10%, more preferably between 0,25% and 1%. It has been found that said amount of crosslinkers does not negatively influence the polymerisation speed and also said amount of crosslinkers ensures that the formed hyperbranched polyamides have the desired solubility and the desired characteristics for a glue comprising said raw material.

[0045] Preferably adding said crosslinkers is done in a weight ratio of crosslinkers upon amino acids of between 0,09% and 10%, more preferably between 0,23% and 1%. For example adding said crosslinkers is done in a weight ratio of crosslinkers upon dry weight base material of between 0,02% and 8%, for example between 0,5% and 1%.

[0046] In a specific embodiment, the hyperbranched polyamides have a number average molecular weight of between 500 and 100000 g / mol, for example between 5000 and 50000 g / mol, or for example between 10000 and 25000 g / mol. The reactivity of the hyperbranched polyamides, when the raw material is for example used to glue plant particles together, 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 the boards. The number average molecular weight of hyperbranched polyamides can be determined for example by low angle laser light scattering (LALLS). Alternatively or additionally, the average molecular weight can be determined by gel permeation chromatography (GPC). By making use of these crosslinkers, said high molecular weight and a dense, but well three-dimensional distributed polymer can be obtained in a faster manner without compromising the solubility of the polymer. When the raw material is for example used to impregnate papers or other carrier layers, then the number average molecular weight can be between 1000 and 5000 g / mol.

[0047] In a very preferred embodiment according to the first aspect of the invention and / or according to the second aspect of the invention, said amino acids of the base material are chosen from the list of: lysine, arginine, glutamine, asparagine, histidine.

[0048] Preferably, according to the first aspect of the invention and / or according to the second aspect of the invention, said amino acids of the base material comprise at least 90 wt% of lysine, more preferably at least 90 wt% of L-lysine or L-Lysine monohydrate. Said amino acids for example comprise at least 95 wt% or at least 99 wt% of lysine. The formed hyperbranched polyamides can then be indicated as hyperbranched polylysine. Therefore a hyperbranched polylysine according to the invention does not necessarily consists of lysine. Lysine can be produced with the aid of micro-organism, such that said base material can be bio-based. For example use can be made of Corynebacterium (Gram-positive), for example Corynebacterium glutamicum, or Escherichia coli (Gramnegative), to produce L-lysine. Small amounts of other amino acids, such as glutamine and / or histidine, can be present in the base material.

[0049] Preferably said base material is the result of a fermentation process by lysine producing micro-organisms, such as Corynebacterium glutamicum, or Escherichia coli. For said micro-organisms to produce lysine, at least a carbon source and a nitrogen source is provided. Said carbon source can be saccharides, for example glucose, fructose, sucrose, blackstrap molasses, beet molasses, starch hydrolysates, cellulose, hemicellulose and / or lignin. As nitrogen source can be used corn steep liquor, yeast extract, tryptone, peptone, soybean cake hydrolysate, casein hydrolysate and / or urea. As an alternative nitrogen source or in addition, an ammonia source can be used. For example mixtures of ammonium salts, such as ammonium sulphate or diammonium phosphate, can be used or ammonium nitrate, ammonium phosphate, ammonium chloride, ammonium acetate, amino acid mixtures and ammonium carbonate. Ammonium sulphate can be obtained as a byproduct in manure processing or after stripping of ammonia-containing gases. In other words, the production of amino acids such as lysine can completely or substantially take place based on bio-based materials and / or waste materials. Often, some vitamins are also added for having a good L-lysine fermentation with for example C. glutamicum. Biotin, thiamine, HC1 salts, pantothenic acids, Ca-salts and / or nicotinamide can also be added. It has been found that high yields of L-lysine fermentation are obtained when using beet melasse and / or Com steep liquor, as such resulting a base material that is very useful for producing hyperbranched polylysine. Preferably the corn is steeped with sulphur dioxide, for example up to two days. This leads to a base material with a high sulphur content, for example of about 4 wt%. Such an amount of sulphur leads to a good production of hyperbranched polylysine, and further a glue comprising said base material is very suitable for bonding plant particles together.

[0050] The base material provided in the invention according to the first and / or the second aspect, can comprise sulphur, more preferably comprises between 2 wt% and 5 wt% of sulphur, for example 4 wt%, based upon dry matter.

[0051] Preferably said base material is the result of a fermentation process by lysine producing micro-organisms, such as Corynebacterium glutamicum, or Escherichia coli. More preferably the base material is a fermentation broth, or the result of a fermentation broth that has undergone a dewatering step to obtain a percentage of dry matter of between 30 and 70 weight percentage. The result of the fermentation process is preferably a fermentation broth comprising:

[0052] -L-lysine and optionally other amino acids, for example between 80 and 120 g / liter of L- lysine

[0053] -dry cellular matter, for example between 10 and 40 grams / liter;

[0054] -carbohydrates;

[0055] -salts, such as potassium salts or magnesium salts;

[0056] -optionally enzymes excreted by the micro-organisms during fermentation. For the method according to the first and / or the second aspect of the invention use can made of this fermentation broth as base material, and this without any intermediate purification steps. This means that dry matter, which is not L-lysine, is not removed or hardly removed from the fermentation broth. Optionally one or more dewatering steps can be performed before using this fermentation broth to produce hyperbranched polylysine. Optionally one or more filtration steps can be performed, for example a microfiltration step, before using this fermentation broth to produce hyperbranched polylysine. The benefit of not (completely) removing said dry cellular matter and / or said carbohydrates, is that the base material then comprises said dry cellular matter and / or said carbohydrates, such that said dry cellular matter and / or said carbohydrates can contribute to characteristics of a glue comprising said raw material formed from said base material. For example carbohydrates and / or dry cellular matter can be incorporated in formed hyperbranched polylysine and as such enhance the solubility of said hyperbranched polylysine. In the raw material, said carbohydrates and / or dry cellular matter can be present alongside the formed hyperbranched polyamides. When using the raw material for a glue, said carbohydrates and / or dry cellular matter can react with said hyperbranched polyamides and contribute to the adhesive characteristics of said glue. Preferably the micro-organisms have been inactivated before using this fermentation broth as base material. This can for example be done by heat treatment and / or the addition of acid. Said carbohydrates can comprise saccharides, for example glucose, fructose, sucrose, starch.

[0057] In a very preferred embodiment said fermentation broth comprises at least 60 wt% of amino acids based on dry weight, preferably at least 70 wt%, for example 75 wt% and 80 wt%. More preferably said base material comprises at least 60 wt% of amino acids based on dry weight, preferably at least 70 wt%, for example 75 wt% and 80 wt%. The result is a raw material with a sufficiently high amount of hyperbranched polyamides.

[0058] In a very preferred embodiment the fermentation broth, in addition to said amino acids, further comprises one or more of the following list:

[0059] -a carbon source; -a nitrogen source, such as ammonium sulphate;

[0060] -micro-organisms, preferably remnants of micro-organisms;

[0061] -salts, such as potassium salts or magnesium salts;

[0062] -ammonium

[0063] -enzymes; and wherein preferably the fermentation broth is in liquid form and comprises between 50 and 250 grams / liter of amino acids and between 5 and 100 grams / liter of other dry matter from the said list, and wherein more preferably the fermentation broth comprises between 80 and 120 grams / liter of amino acids and between 10 and 40 grams / liter of other dry matter from the said list. The carbon source can comprise saccharides. For example the carbon source can be glucose, fructose, sucrose, blackstrap molasses, beet molasses, starch hydrolysate or combinations of the above.

[0064] Preferably at least one of said carbon source and / or at least one of said nitrogen source are incorporated in said formed hyperbranched polyamides.

[0065] Preferably, the fermentation broth is an aqueous fermentation broth that comprises between 10 and 70 weight percentage of water, and wherein preferably said fermentation broth has undergone a dewatering step to obtain said percentage of water. Dewatering can for example be done by filtration and / or centrifugation and / or concentration.

[0066] In alternative embodiment, instead of using the fermentation broth as a base material, the cell mass can be separated from the L-lysine and optionally other amino-acids, for example by centrifugation followed by microfiltration and / or for example by recovering said L-lysine an optionally other amino-acids during an ion-exchange step. The result is a liquid L-lysine freebase concentrate. In this alternative embodiment the base material is said liquid L-lysine freebase concentrate.

[0067] In a very preferred embodiment according to the first aspect and / or the second aspect of the invention, the polymerisation of said amino acids into hyperbranched polyamides comprises at least a heating reaction that is preferably performed in batch, and is preferably a heating reaction, wherein by addition of heat, polymerisation of said amino acids is obtained, wherein said base material is an aqueous material and the polymerisation of said amino acids into hyperbranched polyamides preferably at least comprises the following consecutive steps:

[0068] -a first step in which the base material is brought into a vessel;

[0069] -a second step in which said base material is heated to boiling;

[0070] -a third step wherein the temperature is increased to a reaction temperature in which polymerisation takes place, for example a reaction temperature of between 105°C to 260°C, preferably at most 240°C. Preferably during this third step, distillation takes place and this more preferably until all water is distilled and the amino acids or amino acid polymers are in a melt phase.

[0071] This is a batch process which allows to produce raw material within certain characteristics range. A glue comprising said raw material having said characteristics range, preferably results in a glue with the desired characteristics. Preferably the temperature inside said vessel does not exceed 200°C.

[0072] Further preferably the polymerisation of said amino acids into hyperbranched polyamides comprises at least the said first, second and third step and wherein said polymerisation further comprises:

[0073] -a fourth step wherein the temperature is further increased, preferably stepwise, to preferably between 160°C and 220°C, more preferably to between 180 °C and 215°C, most preferably at most 200°C, for example to 195 °C;

[0074] -a fifth step wherein the heating and / or the polymerisation is stopped;

[0075] -an optional sixth step wherein water is added until a solution is obtained of between 50 and 70% solids, more preferably a solution of between 55 and 65% solids.

[0076] With the aid of all said steps, uniform hyperbranched polyamides can be obtained, e.g. a uniform hyperbranched polyamides solution can be obtained.

[0077] Further, in a preferred embodiment, the method comprises said step of adding crosslinkers wherein said crosslinkers are preferably added at least partially during the first step or during the second step or during the third step. In a very preferred embodiment said crosslinkers are added in said first step, such that the crosslinkers get well incorporated into the formed hyperbranched polyamides.

[0078] Further, in a preferred embodiment, the method comprises said step of adding catalysts wherein said catalysts are preferably added at least partially during the first step or during the second step or during the third step. In a very preferred embodiment said catalysts are added in said first step and / or in said second step, such that the catalysts are present when polymerisation starts.

[0079] Further in a very preferred embodiment, the method comprises said step of adding crosslinkers wherein said crosslinkers are preferably added at least partially during the first step or during the second step or during the third step, wherein the method comprises said step of adding catalysts wherein said catalysts are preferably added at least partially during the first step or during the second step or during the third step, and wherein more preferably said crosslinkers are added before adding said catalysts. In a particularly preferred embodiment said crosslinkers are added in said first step and said catalysts are added in said first and / or in said second step. Preferably all the crosslinkers are added before addition of said catalysts starts. Of course, embodiments wherein said crosslinkers and catalysts are added (partially) simultaneously to said vessel are possible. In a specific embodiment at least two types of catalysts are used and said two types of catalysts are added to said vessel at different times. The latter allows a very controlled steering of said polymerisation reaction, such that the formed hyperbranched polyamides of different batches can be very similar.

[0080] Preferably the polymerisation of said amino acids in said vessel takes place in an inert atmosphere. With an inert atmosphere is indicated that no oxygen or hardly any oxygen is present. Use can be made of for example nitrogen gas or argon gas, preferably use is made of argon gas.

[0081] In another preferred embodiment according to the first and / or the second aspect of the invention, the polymerisation of said amino acids into hyperbranched polyamides is done by extrusion, preferably by reactive extrusion. With reactive extrusion (REX), the base material, and said possible crosslinkers and / or catalysts, are placed in an extruder. By means of extrusion, hyperbranched polyamides can be formed in a rapid and efficient manner. This because not only heat aids with said polymerisation, but also shearing forces aid with said polymerisation. The advantage of an extruder is that the temperature and / or pressure in the various zones of the extruder can be optimized. In extrusion, one can also simply add said other components such as said crosslinkers and / or catalysts, in order to accelerate and / or control the polycondensation, and this at the desired time / moment. For example one can easily add between 0,05 and 2 wt% of butoxides, such as Ti(OBu)4. It is also possible to easily carry out degassing using an extruder. The degree of polymerisation of the obtained hyperbranched polyamides can thus also be kept sufficiently homogeneous. This is also a stable process, so that hyperbranched polyamides can be produced in a uniform manner. The production conditions can also be adapted to the desired hyperbranched polyamides to be obtained. Preferably the average temperature in said extruder, during extrusion, is higher than 230°C, preferably between 245°C and 270°C, such as 250°C or 260 °C. By means of extrusion, customized hyperbranched polyamides can also be formed. Preferably said crosslinkers are added (partially) simultaneously with said base material to the extruder. Said catalysts can be added at a later time to the extruder then the base material and / or (partially) simultaneously with the base material. If use is made of at least two type of catalysts, said catalysts can be added to the extruder at different times.

[0082] Preferably REX makes use of a twin screw extruder e.g. an extruder with two screw. With the aid of a twin screw extruder excellent shearing forces are present. Preferably the twin screw extruder has different zones, e.g. a zone for transport, a zone for mixing, a zone for polymerisation, etc.

[0083] Preferably REX makes use of at least one screw, preferably two screws in the form a twin screw extruder, wherein each screw comprises a shaft and screw elements attached to said shaft. A said screw preferably has differently shaped screw elements, said differently shaped screw elements preferably falling together with said different zones as indicated for the twin screw extruder. Said screw elements are then adapted to the function they have to perform, e.g. transporting, mixing, polymerisation. Preferably the polymerisation of said amino acids in said extruder takes place in an inert atmosphere. With an inert atmosphere is indicated that no oxygen or hardly any oxygen is present. Use can be made of nitrogen gas or argon gas, preferably use is made of argon gas. With the aid of an inert atmosphere, oxidative degradation can be avoided.

[0084] When use is made of REX, use can be made of a said lysine freebase as base material. However it is also possible to make use of a said fermentation broth. If use is made of a said fermentation broth, said fermentation broth is preferably evaporated under high pressure to obtain a fermentation broth melt, wherein said fermentation broth melt is then fed to the extruder.

[0085] The result of REX can be hyperbranched polylysine which is soluble in water up to 60 wt%. Said dissolved hyperbranched polylysine in water for example having an acidity of between pH 11 and pH 12.

[0086] In a specific embodiment according to the first and / or the second aspect of invention, the polymerisation of said amino acids into hyperbranched polyamides is done in two subsequent phases, said phases comprising extrusion, preferably reactive extrusion, and comprising a heating reaction, preferably in batch. Said extrusion can comprise the characteristics as described above and said heating reaction can comprise the characteristics as described above.

[0087] For example said polymerisation of said amino acids into hyperbranched polyamides can firstly comprise said heating reaction, subsequently followed by said extrusion. Said heating reaction can be as described above and then preferably at least comprises said first step, said second step and said third step. In said heating step said base material is used. Preferably said polymerisation is sufficiently low, such that it makes sense to further polymerise by extrusion. Therefore said heating reaction can only comprise said first, second and third step. For example the obtained polyamides can for example not be hyperbranched yet and / or the number average molecular weight can be low, for example lower than 20000 g / mol or lower than 10000 g / mol or lower than 5000 g / mol. Of course embodiments also having said fourth step, or also having said fourth and fifth step, or also having said fourth, fifth and sixth step can be present. The result of said heating reaction is an intermediate product comprising polyamides and optionally amino acids. Said intermediate product than is added to the extruder and further polymerized. In this example said crosslinkers and / or catalysts can be added at different times. In a first option said crosslinkers can already be added during said heating reaction and said catalysts can only be added to said extrusion. In a second option said crosslinkers and catalysts can already be added during said heating reaction and further catalysts can be added to said extrusion.

[0088] In another example polymerisation of said amino acids into hyperbranched polyamides can firstly comprise said extrusion, subsequently followed by said heating reaction. Said extrusion can be described as above, wherein preferably said polymerisation is sufficiently low, such that it makes sense to further polymerise by a heating reaction. For example the obtained polyamides can for example not be hyperbranched yet and / or the number average molecular weight can be low, for example lower than 20000 g / mol or lower than 10000 g / mol or lower than 5000 g / mol. The results is an intermediate product, wherein this intermediate product is added to a said vessel to perform said heating reaction as described above, wherein said intermediate product then serves as a base material. Preferably said heating reaction comprises at least said first, second and third step and more preferably also said other subsequent steps. In this example said crosslinkers and / or catalysts can be added at different times. In a first option said crosslinkers can already be added during said extrusion and said catalysts can only be added to said heating reaction. In a second option said crosslinkers and catalysts can already be added during said extrusion and further catalysts can be added to said heating reaction.

[0089] Preferably, according to the first and / or the second aspect of the invention, after the step of polymerizing said amino acids into hyperbranched polyamides, water is added for dissolving the hyperbranched polyamides. In this way a raw material is formed that can be immediately used as a component of glue. In addition to adding said water, amino acids, such as lysine, glutamine, histidine, asparagine, can be added. By adding said amino acids, the viscosity of the raw material is reduced, and this without compromising upon the adhesive strength of the glue, such that a glue with the desired viscosity can be obtained.

[0090] According to a first variant of the first and / or the second aspect of the invention. The base material is a said fermentation broth and no said crosslinkers and no said catalysts are added to form said raw material.

[0091] The invention, according to a third aspect of the invention, relates to a glue for bonding plant material, e.g. plant particles, such as vegetable fibres and / or wood chips and / or wood pieces, into boards, wherein the glue comprises at least a first raw material comprising hyperbranched polyamides. Said plant particles can be lignocellulosic material.

[0092] Said first raw material can be obtained from polymerisation of a fermentation broth comprising amino acids, and said first raw material can further comprises one or more components of the following list:

[0093] -a carbon source, such as carbohydrates;

[0094] -a nitrogen source, such as com steep liquor, yeast extract, tryptone, peptone, soybean cake hydrolysate, casein hydrolysate and / or urea;

[0095] -dry cellular matter, for example remnants of micro-organisms;

[0096] -salts, such as potassium salts or magnesium salts;

[0097] -enzymes excreted by micro-organisms during fermentation;

[0098] -catalysts, such as lewis acids, lewis bases, Bronsted acids or Bronsted bases.

[0099] Said hyperbranched polyamides of said raw material can have incorporated 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.

[0100] The benefit of having one or more components of the abovementioned list is that said components can contribute to the desired characteristics of the glue. For example said carbon source, for example carbohydrates such as glucose, fructose, sucrose and starch, can react with the hyperbranched polyamides and as such enhance the adhesive characteristics of the glue. Said catalysts can catalyse the curing of the glue. Said one or more components can also give the glue the desired viscosity and / or acidity. For example if said raw material comprises Lewis acids, said Lewis acids can give the glue the desired acidity.

[0101] Hyperbranched polyamides with said incorporated crosslinkers have a good solubility in water, such that a glue comprising said raw material can be easily applied to plant particles, for example can be applied in a liquid state to said plant particles.

[0102] In a very preferred embodiment of the third aspect of the invention, said raw material is obtained from a method according to the first and / or the second aspect of the invention.

[0103] In a preferred embodiment the glue, in addition to said first raw material, comprises one or more additional raw materials of the following list:

[0104] -crosslinkers, wherein these crosslinkers are preferably selected from the group comprising polyketones, polyesters, isocyanate dispersions, a-dicarbonyls, epoxides, glyoxal and other aldehydes;

[0105] -a carbohydrate-containing material;

[0106] -additives, preferably chosen from the list of bases, salts, metal-containing components, thickeners;

[0107] -a denaturated and / or fermented flour.

[0108] If one or more additional raw materials are present, said glue is then a combination of said first raw material and a said additional raw material or a combination of said first raw material and said additional raw materials. Said first raw material and at least one of said additional raw materials can be mixed together before adding it to said plant particles for bonding of said plant particles. Said glue can be a one-component glue, which means that all of said raw materials are combined and stored together before using said glue or said glue can be a two-component glue or a multi-component glue wherein said raw materials are only mixed together shortly before using said glue or during bonding of said plant particles. Said glue can also comprise a so-called prereact or prereacted composition, wherein said prereact or prereacted composition at least comprises reaction products of the hyperbranched polyamides of the first raw material and carbohydrates of the carbohydrate-containing material.

[0109] Preferably said hyperbranched polyamides of the first raw material 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 the boards. 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).

[0110] Different options for said glue are possible. Here below three possible options are further explained, however this is a non-exhaustive list.

[0111] In a first option said glue is a combination of said first raw material and one or more crosslinkers, preferably selected from the list of polyketones, polyesters, isocyanate dispersions, a-dicarbonyls, epoxides, glyoxal and other aldehydes. Excellent results are achieved with the aid of epoxides, such as diepoxides or triepoxides or polyepoxides or a combination of various aforementioned epoxides. These epoxides, for example the diepoxides or the triepoxides, may for example comprise one or more oxirane end groups and preferably comprise two or more oxirane end groups. Examples are diglycidyl ethers or triglycidyl ethers. 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 known that epoxides react with amines. The weight ratio of crosslinkers to hyperbranched polyamides is further preferably between 0,02 and 0,15. It is thus for example possible for there to be between 3 and 6 percent by weight of epoxides in relation to hyperbranched polyamides. A higher proportion of crosslinkers contributes to the water resistance of the glue and thus of the board comprising this glue. The content of the crosslinkers must also not be too high, as this may lead to prepolymerization of the glue, prior to the pressing of the board. This weight ratio ensures optimal technical characteristics, more particularly a better tensile strength, flexural strength and compressive strength and a better water resistance. Such boards are therefore not only suitable for applications in dry indoor environments (service class 1) but are also very suitable in more moist spaces, such as interior spaces such as bathrooms (service class 2).

[0112] Preferably, for this first option, the glue is added to plant particles for bonding of said plant particles in a weight ratio of hyperbranched polyamides to plant particles between 0,03 and 0,15. Also preferably, the weight ratio of crosslinkers to hyperbranched polyamides is between 0,02 and 0,15. Preferably, the glue comprises water as solvent and thus forms an aqueous solution which, preferably, comprises between 50 and 70 percent by weight of hyperbranched polyamides. For the latter, said raw material preferably comprises a least 70 percent by weight of hyperbranched polyamides. Preferably said glue has a viscosity of at most 20 000 mPa.s, preferably at most 2000 mPa.s, at 20°C and 1.013 bar.

[0113] In a second option said glue is a combination of said first raw material and at least a second raw material which is a carbohydrate-containing material. Said carbohydrate- containing material preferably comprises reducing sugars, therefore inducing Maillard reactions creating Amadori and / or Heyn’s reactants. Optionally said glue further comprises one or more of the above-mentioned abovementioned crosslinkers of the first option. Said second raw material can comprise carbohydrates as described for the glue of WO 2023 / 218343 and the amount of carbohydrates and hyperbranched polyamides and / or the possible additives and / or the possible crosslinkers can also be as described in WO 2023 / 218343. The specific features relating to the glue, and more specifically related to the crosslinkers, additives and carbohydrates, as described in WO 2023 / 218343 are hereby incorporated by reference.

[0114] Preferably, for this second option, the glue comprises additives such as bases and / or salts. Preferably said bases are K2CO3. Preferably the bases make up between 0,5 and 20 wt% based on dry matter content of the glue, for example between 1 and 20 wt%, for example between 2 and 6 wt% or between 3 and 5 wt%. The glue is preferably added to plant particles for bonding of said plant particles in a weight ratio of said salts relative to the plant particles of 0,01 and 1, for example between 0,02 and 0,2, or between 0,1 and 1, or between 0, 1 and 0,2. The salts of a hypochlorous acid preferably make up between 0, 1 and 20 wt% based on dry matter content of the glue, for example between 0,2 and 10 wt%, for example between 1 and 20 wt%.

[0115] The additives preferably comprise crosslinkers chosen from the group comprising: a- hydroxyaldehydes, glyceraldehyde and a-dicarbonyls. The percentage by weight of said crosslinkers relative to plant particles is the preferably between 0,02 and 0,16, preferably between 0,04 and 0,08. Said crosslinkers preferably make up between 0,3 and 3 wt% based on dry matter content of the glue. The additives can also comprise amine crosslinking agents, wherein preferably these amine crosslinking agents are selected from the group comprising polyketones, polyesters, isocyanate dispersions, epoxides, glyoxal and other dialdehydes. The additives can also comprise metal-containing components, for example metal oxides and / or metal hydroxides and / or metal salts. The weight ratio of said amine crosslinking agents to hyperbranched polyamides is preferably between 0,02 and 0,15.

[0116] Preferably, for this second option, the dry weight of the first raw material to the total dry weight of the glue is between 15% and 40%, for example about 30%. The second raw material preferably takes up between 50% and 85% of the total dry matter weight of the glue. Said glue is formed by combining said first raw material, said second raw material and optional other components as described for example in this description -e.g. additives and crosslinkers-. Said first raw material preferably comprises between 50 and 70 wt% of dry matter. Preferably said second material comprises between 50 and 70 wt% of dry matter. In this way the glue can be easily applied to plant particles, such as wood chips or wood fibers, to form a board. If the second raw material is invert sugar, no said other components, such as additives and crosslinkers, are needed, however these can of course be added.

[0117] For said second option, use can be made of a prereact when bonding said plant particles together with said glue. Firstly a said second raw material comprising said carbohydrates and a portion of said first raw material are combined and heated to form a prereact. When said prereact is formed, the remaining portion of said first material is added to the prereact, as such forming a glue that can be added to the plant particles. In this manner a very reactive glue is formed. If one or more of abovementioned additives are present, these can be added prior to or during formation of the prereact or after formation of the prereact. Surprisingly, for the second option, it has been found that when the second material comprises at least 50 wt% of invert sugar based upon the total weight of carbohydrates, preferably at least 80 wt% and most preferably at least 95 wt%, a very reactive glue can be made and this even without the need of abovementioned prereact.

[0118] In a third option said glue is a combination of said first raw material and at least a second raw material which comprises an at least partially denaturated and / or fermented flour. Optionally said glue further comprises one or more of the above-mentioned additives and / or one or more of the abovementioned crosslinkers. For example said second raw material is a denatured flour, wherein this denatured flour is preferably obtained by denaturation under the influence of heat and / or acidity and / or enzymes and / or the addition of chemicals, wherein these chemicals are preferably selected from the group comprising: urea, guanidine, sulphates, sulfoxides, sulfonates, propylene glycol. The second raw material can also be a fermented flour, wherein this fermented flour is preferably fermented by at least the addition of an amount of already-fermented flour. The second raw material can also be a flour that has undergone both denaturation and fermentation, wherein fermentation has preferably taken place first, followed by denaturation. The dry matter of the first raw material can take up between 10 and 45 wt% of the total weight of the dry matter glue. The dry matter of the second raw material can take up between 30 and 70 wt% of the total weight of the dry matter glue. The flour can for example be a soy flour, a lupine flour, a wheat flour, a canola flour, a pea flour and / or a guar flour.

[0119] Preferably, for the abovementioned three options but also for other options, said glue comprises crosslinkers and / or additives.

[0120] The crosslinkers are preferably selected from the group comprising polyketones, polyesters, isocyanate dispersions, a-dicarbonyls, epoxides, glyoxal and other aldehydes. With the aid of crosslinkers, curing of said glue can be enhanced, e.g. curing can take place with less energy and / or in a faster manner. The weight ratio of crosslinkers to hyperbranched polyamides is preferably between 0,02 and 0,15. It is thus for example possible for there to be between 3 and 6 percent by weight of crosslinkers, for example epoxides, in relation to hyperbranched polyamides. Excellent results are achieved with the aid of epoxides, such as diepoxides or triepoxides or polyepoxides or a combination of various aforementioned epoxides. Diglycidyl ethers and triglycidyl ethers are very suitable epoxides. These epoxides, for example the diepoxides or the triepoxides, may for example comprise one or more oxirane end groups and preferably comprise two or more oxirane end groups. 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 known that epoxides react with amines. However, it is exceptional here that, in the case of hyperbranched polyamides, epoxides can be added without pre-polymerization when the plant particles is being treated with glue, prior to the pressing of the board. The mixture has a shelf life of at least two hours without increase of viscosity. It is only when pressure and temperature are added in the press that the epoxide becomes active. This does not impede the pressing of the board and makes it possible to establish the bond between the plant particles in a highly satisfactory manner. These crosslinkers may have already been mixed with the first raw material of the used glue in advance and stored thus. However, the crosslinkers may also be combined with the first raw material of the used glue shortly before the treatment with glue. The glue used is then, for example, of two-component form, comprising a first component comprising the first raw material and a second component comprising crosslinkers, wherein these two components are combined only prior to the treatment with glue or during the treatment with glue of the plant particles. Said crosslinkers may also be considered separate ingredients, independently of the glue used, in the production of boards, wherein the glue used then forms, together with the crosslinkers, the glue based on hyperbranched polyamides that is present in the board.

[0121] The additives are preferably chosen from the list of bases, salts, metal-containing components, thickeners. The thickeners can be galactomannans or gelling agents.

[0122] In a very preferred embodiment the glue comprises water as solvent and thus forms an aqueous solution which, preferably, comprises between 20 and 70 percent by weight of hyperbranched polyamides.

[0123] In a very preferred embodiment, the glue, in addition to said first raw material, comprises at least a material comprising carbohydrates, said carbohydrates comprising invert sugar, wherein preferably the weight percentage of said invert sugar upon the total weight of said carbohydrates is at least 80 wt% preferably at least 90 wt% and more preferably at least 95 wt%. A glue according to the second option as described above, comprising such a high amount of invert sugar, shows superior characteristics and is very suitable for manufacturing a board.

[0124] Said glue, in addition to said first raw material, can comprise additives for enhancing water resistance, said additives preferably being chosen from the list of:

[0125] -a silicon containing compound, such as fumed silica or silanes or polysiloxanes;

[0126] -a metallic soap;

[0127] -a thermoplastic material;

[0128] -inorganic fillers such as CaCCh, talc, vermiculite;

[0129] -moisture absorbing material;

[0130] -thermo-initiator;

[0131] -epoxy;

[0132] -zero-poisson’s ratio material. Said thermoplastic material can be chosen from the list of: polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), polyethylene vinyl acetate (pEVA), polyvinyl alcohol (PVA), polybutylene succinate (PBS), polyvinyl chloride (PVC), polymethyl methacrylate (PMMA), polyurethane (PU), polypropylene (PP) and polyethylene (PE). Said metallic soaps preferably comprise an aliphatic chain comprising at least 8 carbons, more preferably at least 12 carbons and most preferably at least 16 carbons. More preferably said metallic soaps also comprise one, two or more shorter aliphatic chains, e.g. aliphatic chains with at most 6 carbons, preferably at most 4 carbons. Said metallic soaps can be obtained from animal fats or plant / vegetable fats. The metallic soaps are preferably zinc metallic soaps or calcium metallic soaps or magnesium metallic soaps. An example of possible metallic soaps is zinc stearate. Metallic soaps can contribute to the water resistance of a board comprising said glue, but can also enhance the soap resistance of a said board.

[0133] Preferably said additives are present in amount of between 1% and 25% by weight based upon the dry matter weight of the glue, preferably of between 5% and 15%.

[0134] Said plant particles can be coated plant particles, for example coated wood chips or coated wood fibers. With coated plant particles are indicated plant particles which have been coated with a coating material and which are preferably entirely encapsulated by said coating material. Said coating material can have water repellent properties to provide the board formed with said coated plant particles with additional water resistant / water repellent features. Said coating material can for example be chosen from the list of: pMDI coating, MDI coating, a coating comprising thermoplastic material, a coating comprising additives for enhancing water resistance as mentioned above, an acrylate, etc.

[0135] Said glue according to the third aspect of the invention can also be used as a resin to for example impregnate paper to form impregnated paper. For example such impregnated paper can be attached to a wood based substrate, such as a wood fibreboard or a particle board, to form a laminate, or to a thermoplastic based substrate or another type of substrate and / or said impregnated paper can be part of a high pressure laminate (HPL) or a continuous pressure laminate (CPL) or a compact board. High Pressure Laminates (HPL) are built up from several sheets, preferably resin-impregnated sheets, with a decor on top and optionally a protective layer. HPL is produced by pressing the various layers of the HPL together under temperature and pressure, which results in curing of the resin. When said HPL are produced in a continuous manner, these HPL can be indicated as CPL. Compact laminate is preferably constructed with layers of resin-impregnated kraft papers which are sandwiched between resin-impregnated decorative papers, e.g. printed papers and / or dyed papers and / or papers with a uniform colour, and which are optionally further sandwiched between protective layers, e.g. wear layers, such as resin- impregnated papers and / or lacquer layers and / or UV-cured layers. Said different layers are pressed together to form said compact laminate.

[0136] The invention according to a fourth aspect, relates to a resin for impregnating and / or coating a carrier layer, such as a paper or a textile layer or a cardboard, wherein the resin comprises at least a first raw material comprising hyperbranched polyamides, wherein said first raw material is preferably obtained from polymerisation of amino acids or a fermentation broth comprising amino acids. Said resin is preferably a glue according to the third aspect of the invention or according to the variant of the third aspect of the invention, hereafter disclosed.

[0137] The invention also relates to a material comprising at least one paper impregnated with a resin, wherein the resin is a resin according to the fourth aspect of the invention, wherein said material is preferably chosen from the list of a HPL, a CPL or a compact board. The invention for example relates to a laminate comprising two or more sheets, said laminate preferably comprising at least two or more paper sheets, and a cured glue that bonds at least two sheets of said two or more sheets to each other, wherein the cured glue is obtained by the curing of a glue according to the third aspect of the invention. Said glue according to the third aspect of the invention, can instead of being used for bonding only plant particles together, be used for bonding a mixture of plant particles and alternative particles together or can be used for bonding alternative particles together, wherein preferably said alternative particles are less prone to swelling. For example said alternative particles can be 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 is wherein all the plant particles are replaced by a mineral, for example by mineral fibers. Said mineral can be magnesium oxide. A second example is wherein the plant particles are partially replaced by a mineral, for example by mineral fibers. Said board then for example comprises a combination of magnesium oxide and wood fibers. The invention therefore also relates to boards which comprises said alternative particles and optionally plant particles.

[0138] In a variant of the third aspect of the invention, said glue comprises a raw material comprising hyperbranched polyamides, however said raw material is or is not obtained from a polymerisation of a fermentation broth comprising amino acids. In this variant said hyperbranched polyamides can be obtained from other sources than said fermentation broth and also said raw material can or cannot comprise one or more of the following list:

[0139] -a carbon source, such as carbohydrates;

[0140] -a nitrogen source, such as com steep liquor, yeast extract, tryptone, peptone, soybean cake hydrolysate, casein hydrolysate and / or urea;

[0141] -dry cellular matter, for example remnants of micro-organisms;

[0142] -salts, such as potassium salts or magnesium salts;

[0143] -enzymes excreted by micro-organisms during fermentation;

[0144] -catalysts, such as Lewis acids, Lewis bases, Bronsted acids or Bronsted bases; and / or wherein said hyperbranched polyamides of said raw material can or cannot have incorporated 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.

[0145] The preferred / specific features of the glue which do not relate to said raw material obtained from a polymerisation of a fermentation broth comprising amino acids, also apply to this variant. In this variant said raw material comprising hyperbranched polyamides can be from different sources.

[0146] The invention, according to a fifth aspect, 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 a glue that comprises a first raw material comprising hyperbranched polyamides, wherein said first raw material is a raw material obtained by a method according to first and / or the second aspect of the invention and / or said glue is a glue according to third aspect of the invention or according to the variant of the third aspect of the invention.

[0147] Surprisingly, it was found that a glue comprising a raw material according the first and / or the second aspect of the invention and / or a glue according to the third aspect of the invention or the variant of the third aspect of the invention, has particularly favourable adhesion strength and is highly suitable for bonding plant particles with one another to form boards. In addition, boards in accordance with the fifth aspect of the invention can show better technical properties than existing boards that are glued with existing aminoplast polymer glues, such as conventional urea formaldehyde glues. In this manner, greater stiffness (N / mm2) and transverse tensile strength (N / mm2) are obtained and / or greater water resistance. This therefore concerns highly stable, strong boards, which in addition retain at least the same water resistance as the above-mentioned existing boards.

[0148] For example, in a board wherein the dry matter weight ratio of the glue to plant particles, such as wood chips, is at least 8 wt% and which has a density greater than 700 kg / m3, at least the following values can be achieved:

[0149] Transverse tensile strength (in accordance with EN 319): 1,0 N / mm2

[0150] Bending strength (in accordance with EN 310): 16,0 N / mm2Young's Modulus (in accordance with EN 310): 3100 N / mm2Boiling test after 2 h (in accordance with EN 1087-1): 0.05 N / mm2transverse tensile strength

[0151] In addition, the production of boards in accordance with the fifth aspect of the invention can take place in a similar manner as the production of such boards with conventional urea formaldehyde glues (UF glues). One can then also switch to a glue that is a combination of at least the above-mentioned protein-containing fraction and the above- mentioned second fraction, and this without modifying the production process to an excessive degree. These boards are for example obtained by first providing the plant particles with the glue and then pressing these plant particles provided with the glue into a board-shaped material, wherein this board-shaped material for example is sawn into boards or already forms a board with the desired dimensions. The pressing preferably takes place at an elevated temperature, wherein this temperature can be increased to over 200°C.

[0152] During the production of these boards, the glue will undergo curing. Prior to addition of the glue to the plant particles, some fractions of the glue can already have partially reacted with each other, e.g. use can be made of a prereact, and this is in order to accelerate the curing. The curing preferably comprises polymerisation, but need not be limited to polymerisation.

[0153] This glue does not need to contain formaldehyde, and this glue preferably comprises no formaldehyde, so that this glue has no additional adverse effect on any emissions of formaldehyde.

[0154] This glue can be completely bio-based.

[0155] Preferably, use is made of only one first type of glues to form the boards, namely glues according to the (variant of the) third aspect of the invention, but the boards can also comprise other types of glues. In this manner, one can use a glue mixture comprising the first type of glue and one or more other types of glues, and / or the board can have multiple layers, wherein for a specified layer the first type of glue is used and for another specified layer another type of glue is used. Examples of other glues include conventional UF glues, MUF glues, MUPF glues, PF glues, pMDI glues, polyurethane glues, polyvinyl butyral glues, polyacrylate glues, etc. Polyurethane glues can be used for example in order to increase water resistance and / or flexibility. It is also possible for a board to be formed with various glues of the first type. In this manner, the board can have multiple layers, wherein various glues, including for example all glues comprising a said first raw material, are used for the various layers. The latter various glues can differ in a wide variety of ways. The following is a non-exhaustive list of possible differences, wherein these differences may be combined with one another provided that they do not conflict: dry matter content, additives -types and amounts-, any carbohydrates -types and amounts-, solvent used (water or solvent), etc.

[0156] In a specific embodiment, the board comprises one or more layers, wherein at least one above-mentioned layer comprises the above-mentioned plant particles and the above- mentioned glue, wherein in this layer, the dry matter weight ratio of the glue to plant particles is between 0.03 and 0.15, preferably less than 0.10. If the board comprises several layers, not all layers need comprise the same glue. Therefore, if the board comprises two outer cover layers and one or more central layers, the cover layers and the central layers can comprise another glue. The above-mentioned ratio is also determined by the type of board; for example, in three-layer particle boards comprising a central layer and two outer cover layers, the percentage by weight of glue with respect to plant particles in all layers is between 3% and 15%, wherein the percentages by weight for the cover layers are preferably higher than the percentage by weight of the central layer. In this manner, in the cover layers, the above-mentioned percentage by weight can be between 7 and 14, for example 6, 7, 8, 9, 10, 11 or 12. In the central layer, the above- mentioned percentage by weight can be between 3 and 10, for example 3, 4, 5, 6, 7 or 8. In MDF or HDF or OSB, this percentage by weight can be between 5 and 15, and therefore for example be 6, 7, 8, 9 or 10.

[0157] The plant particles, such as for example wood chips, wood shavings, wood layers, wood fibres or other vegetable fibres, are provided with glue, 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 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. This glue can be a one-component glue, wherein the glue is stored in its entirety and applied in its entirety to the plant particles. The glue can also be a two-component or multi-component glue, wherein the glue comprises two or multiple components that are stored separately, wherein these components are combined prior to gluing and thus applied as a single whole to the plant particles or wherein these components are applied without first being combined to the plant particles, and this process may or may not be simultaneous.

[0158] In a specific embodiment, wherein the board comprises one or more layers, these layers are pressed together, and at least one of the above-mentioned layers comprises the above- mentioned plant particles and the above-mentioned glue, wherein in this layer, the dry matter weight ratio of the glue to plant particles is between 0.03 and 0.15, preferably between 0.04 and 0.1. The board can for example be composed of three or more layers, with outer cover layers and one or more central layers, wherein at least one central layer comprises the above-mentioned plant particles and the above-mentioned glue, and wherein each of the cover layers comprises plant particles and a glue as described above, wherein the weight ratio of the glue to plant particles in the cover layers is greater than the weight ratio of the glue to plant particles in the last-mentioned central layer.

[0159] In a preferred embodiment, the pressing takes place at a temperature of between 150°C and 250°C, with a pressing force of between 1.5 and 5 N / mm2, with the pressing time being at least 3 sec per mm of board thickness. For example, depending on the pressing temperature and the pressing type, the time can be 3 to 7 sec per mm of board thickness. Either a continuous or a discontinuous press can be used. In pressing, the surfaces are preferably sprayed above and below with water, for example between 10 and 50 g / m2of water, in order to promote heat transfer to the middle of the board and shorten the total pressing time.

[0160] In a specific embodiment, the plant particles are covered with glue by injection, atomizing or friction between the plant particles or a combination of these techniques. In this manner, favourable gluing of the plant particles is achieved. This relates to similar or the same gluing that is applied when using common UF glues, with the result that an existing gluing step of an existing production process need not be altered or need be altered in only a slightly limited manner to the glue in accordance with the invention.

[0161] An alternative embodiment of the invention relates to a glue for the bonding of insulation materials, such as glass wool, rock wool, etc., for example to mats, wherein the glue is a glue as described above in the (variant of the) third aspect of the invention. The preferred embodiments of the glue as described above in the (variant of the) third aspect of the invention also apply to this alternative embodiment. By means of this glue, insulation material such as glass wool, rock wool, etc. is then formed. The invention also relates to an insulation material such as glass wool or rock wool comprising a glue as described above and also to a method for the preparation of an insulation material such as glass wool or rock wool, wherein a glue as described above is provided.

[0162] 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.

[0163] Example 1

[0164] A first example of a method according to the first and the second aspect of the invention is the following:

[0165] This first example is a method for manufacturing a raw material of a glue, wherein said raw material comprises hyperbranched polyamides. Said method at least comprises the following steps:

[0166] -provide a base material comprising amino acids. Said base material is a fermentation broth comprising L-lysine, wherein said fermentation broth comprises 50 weight percentage of dry matter. This fermentation broth is obtained with a Corynebacterium glutamicum. L-lysine preferably takes up at least 50 weight percentage of the total amount of dry matter. Further said dry matter comprises dry cellular matter, preferably remnants of Corynebacterium glutamicum, carbohydrates, salts -e.g. potassium salts or magnesium salts-, and optionally enzymes excreted by Corynebacterium glutamicum during the L-lysine fermentation. This fermentation broth is brought into a vessel that is heatable.

[0167] -add 0,15 wt% of zinc acetate to the fermentation broth in the vessel, based upon the dry matter weight of the fermentation broth. This means that if 2 kg of fermentation broth is provided, 1,5 g of zinc acetate is added.

[0168] -add 0,75 wt% of triethanolamine (TEA) to the fermentation broth in the vessel, based upon the dry matter weight of the fermentation broth. This means that if 2 kg of fermentation broth is provided, 7,5 g of TEA is added. TEA can be added in 85 wt% dispensed form. If this is the case 8,76 g of TEA dispension is added.

[0169] The vessel is heated up to 200°C and during this heating, polymerisation of the lysine into hyperbranched polylysine takes place and condensate water is formed. The hyperbranched polylysine at least comprises lysine. The fermentation broth can also comprise glutamine, such that the formed hyperbranched polylysine can comprise glutamine. Further said formed hyperbranched polylysine can also comprise incorporated TEA and incorporated carbohydrates / other components of the fermentation broth The condensate water is continuously removed during said heating. During the heating, mixing takes place, such that heat is well spread during the polymerisation reaction. For example mixing can take place with a stirrer which stirs at at least 80 rounds a minute. Here below possible parameters of the polymerisation reaction are shown.

[0170]

[0171] In minute 345, heating is stopped and water is added to dissolve all the formed hyperbranched polyamides. A total amount of about 730 ml water is added, of which a 70 ml of water disappears again trough vapor formation.

[0172] This raw material formed in example 1 can be used as such, as a component of a glue for bonding plant particles together for forming for example a particle board or a fiber board. For example this raw material can be a said first raw material of the third aspect of the invention.

[0173] Example 2

[0174] Example 2 relates to a glue according to the third aspect of the invention. Said glue comprises the raw material formed in example 1.

[0175] The glue comprises, based upon dry matter, 59 wt% of invert sugar, 32,3 wt% of said raw material of example 1, 6,0 wt% of K2CO3, 1,3 wt% of an epoxy crosslinker and 1,4 wt% of glycerol.

[0176] Example 3

[0177] With the glue of example 2, a particle board was manufactured. This particle board is a particle board according to the fifth aspect of the invention. This particle board is a one layer particle board with the following characteristics: The thickness is between 12 and 12,5 mm. The density is between 700 and 740 g / m2. Pressing time was between 6,8 and 7 mm / s and the pressing temperature was 200°C. The amount of glue is 7 wt% upon dry matter wood chips.

[0178] This board has a transverse tensile strength (in accordance with E319): 1,0 N / mm2Bending strength (in accordance with EN 310): 16 N / mm2

[0179] Modulus of elasticity (in accordance with EN 310): 3100 N / mm2

[0180] Example 4

[0181] With the glue of example 2, a particle board was manufactured. This particle board is a particle board according to the fifth aspect of the invention. This particle board is a three layered particle board with the following characteristics: The thickness is between 12 and 12,5 mm. The density is between 700 and 740 g / m2. Pressing time was between 6,8 and 7,5 mm / s and the pressing temperature was 200°C. This three layered particle board comprises, from top to bottom, a top covering layer, a middle layer and a bottom covering layer. The amount of glue for the middle layer is 6,5 wt% upon dry matter wood chips and the amount of glue for the top and bottom covering layers is 9 wt% upon dry matter wood chips. Similar results for the strength and elasticity as described in example 3, were obtained for this example 4.

Claims

Claims1 A method for manufacturing a raw material, wherein said raw material comprises hyperbranched polyamides, wherein said method at least comprises the steps of: -providing a base material comprising amino acids;-polymerizing said amino acids into hyperbranched polyamides;-adding catalysts to promote said polymerisation of amino acids into hyperbranched polyamides; characterized in that said catalysts at least comprise one or more catalysts chosen from the list of: Lewis acids, Lewis bases, Bronsted acids or Bronsted bases.2.- The method according to claim 1, wherein said catalysts at least comprise one Lewis acid, said Lewis acid preferably being a butoxide, such as titanium butoxide, or being an acetate, such as zinc acetate.3.- The method according to claim 1 or 2, wherein said catalysts at least comprise two types of Lewis acids, said Lewis acids preferably being a stronger Lewis acid, such as titanium butoxide, and a weaker Lewis acid, such as zinc acetate.4.- The method according to claim 3, wherein a first Lewis acid of said two types of Lewis acids is added to said base material before polymerisation of said amino acids into hyperbranched polyamides or is added during polymerisation of said amino acids into hyperbranched polyamides, wherein a second Lewis acid of said two types of Lewis acids is added at a later time then said first Lewis acid and is added during polymerisation of said amino acids into hyperbranched polyamides.5.- The method according to any of the preceding claims, wherein adding said catalysts is done in a molar ratio of catalysts upon amino acids of between 0,01% and 10%, preferably of between 0,05% and 0,1%.

6. The method according any of the preceding claims, wherein adding said catalysts is done in a weight ratio of catalysts upon amino acids of between 0,015% and 15%.7.- The method according to any of the preceding claims, wherein said catalysts at least comprise catalysts comprising a metal ion, preferably comprise Lewis acids comprising a metal ion.8.- A method for manufacturing a raw material, optionally according to any of the preceding claims 1 to 7, wherein said raw material comprises hyperbranched polyamides, wherein said method at least comprises the steps of:-providing a base material comprising amino acids;-polymerizing said amino acids into hyperbranched polyamides;-adding crosslinkers to said base material and / or during polymerisation of said amino acids into hyperbranched polyamides; characterized in that said crosslinkers at least comprise one or more crosslinkers chosen from the list of: crosslinkers with at least one alcohol end group and / or crosslinkers with at least one amine end group and / or trifunctional crosslinkers.9.- The method according to claim 8, wherein said crosslinkers at least comprise one crosslinker with one or more alcohol end groups, said crosslinker preferably being glycerol or a polyol, such as pentaerytritol.10.- The method according to claim 8 or 9, wherein said crosslinkers at least comprise one crosslinker with one or more amine end groups, such as triethanolamine (TEA) or tri ethylenetetramine (TETA) or tetraethylenepentamine (TEPA) or diethylenetriamine (DETA) or 4-(aminomethyl)octane-l,8-diamine.11.- The method according to any of the claims 8 to 10, wherein the crosslinkers are added to the base material before or at the start of polymerizing said amino acids into hyperbranched polyamides.12.- The method according to any of the claims 1 to 7 and according to any of the claims 8 to 11, wherein the crosslinkers are at least partially added before the addition of said catalysts, wherein preferably the catalysts are added during polymerisation of said amino acids into hyperbranched polyamides.13.- The method according to any of the claims 8 to 12, wherein the crosslinkers are incorporated into the formed hyperbranched polyamides during polymerisation of said amino acids into hyperbranched polyamides.14.- The method according any of the claims 8 to 13, wherein adding said crosslinkers is done in a molar ratio of crosslinkers upon amino acids of between 0,1% and 10%, more preferably between 0,25% and 1%.

15. -The method according any of the preceding claims 8 to 14, wherein adding said crosslinkers is done in a weight ratio of crosslinkers upon amino acids of between 0,1% and 10%.16.- The method according any of the preceding claims, wherein the said amino acids are chosen from the list of: lysine, arginine, glutamine, asparagine, histidine.17.- The method according to any of the preceding claims, wherein the said amino acids at least comprise 90 wt% of lysine, preferably at least 90 wt% of L-lysine.18.- The method according to any of the preceding claims, wherein the said base material is a fermentation broth.19.- The method according to claim 18, wherein said fermentation broth comprises at least 50 wt% of amino acids based on dry weight, preferably at least 60 wt%, more preferably at least 70 wt%.20.- The method according to claim 18 or 19, wherein the fermentation broth further comprises one or more of the following list:-a carbon source, such as a carbohydrate;-a nitrogen source;-micro-organisms, preferably remnants of micro-organisms;-salts, such as potassium salts or magnesium salts;-ammonium;-enzymes; and wherein preferably the fermentation broth is in liquid form and comprises for example between 50 and 250 grams / liter of amino acids and between 5 and 100 grams / liter of other dry matter from the said list, and wherein more preferably the fermentation broth comprises between 80 and 120 grams / liter of amino acids and between 10 and 40 grams / liter of other dry matter from the said list.21.- The method according to claim 20, wherein the at least one of said carbon source and / or at least one of said nitrogen source are incorporated in said formed hyperbranched polyamides.22.- The method according to any of the preceding claims 18 to 21, wherein the fermentation broth is an aqueous fermentation broth that comprises between 30 and 70 weight percentage of dry matter, and wherein preferably said fermentation broth has undergone a dewatering step to obtain said percentage of dry matter.23.- The method according to any of the preceding claims 18 to 22, wherein the fermentation broth is an aqueous fermentation broth obtained by microfiltration.24.- The method according to any of the preceding claims, wherein the polymerisation of said amino acids into hyperbranched polyamides is at least a heating reaction that is preferably performed in batch, wherein by addition of heat, polymerisation of said amino acids is obtained, wherein said base material is an aqueous material and the polymerisation of said amino acids into hyperbranched polyamides preferably at least comprises the following consecutive steps:-a first step in which the base material is brought into a vessel;-a second step in which said base material is heated to boiling;-a third step wherein the temperature is increased to a reaction temperature at which polymerisation into hyperbranched polyamides takes place, for example a reaction temperature of between 105°C to 260°C.25.- The method according to claim 24, wherein the polymerisation of said amino acids into hyperbranched polyamides further comprises:-a fourth step wherein the temperature is further increased, preferably stepwise, to preferably between 160°C and 220°C, more preferably between 180 °C and 215°C, most preferably at most 200°C;-a fifth step wherein the heating and / or the polymerisation is stopped;-an optional sixth step wherein water is added until a solution is obtained of between 50 wt% and 70 wt% solids, more preferably a solution of between 55 wt% and 65 wt% solids.26.- The method according to claim 24 or 25 and according to any of the claims 8 to 15, wherein the method comprises said step of adding crosslinkers wherein said crosslinkers are preferably added at least partially during the first step or during the second step or during the third step.27.- The method according to claim 24 or 25 or 26 and according to any of the claims 1 to 7, wherein the method comprises said step of adding catalysts wherein said catalysts are preferably added at least partially during the first step or during the second step or during the third step.28.- The method according to claim 24 or 25 and according to any of the claims 1 to 7 and according to any of claims 8 to 15, wherein the method comprises said step of adding crosslinkers wherein said crosslinkers are preferably added at least partially during the first step or during the second step or during the third step, wherein the method comprises said step of adding catalysts wherein said catalysts are preferably added at least partially during the first step or during the second step or during the third step, andwherein more preferably said crosslinkers are at least partially added before adding said catalysts.

29. The method according to any of the preceding claims 24 to 28, wherein the polymerisation of said amino acids in said vessel takes place in an inert atmosphere.30.- The method according to any of the preceding claims 1 to 23, wherein the polymerisation of said amino acids into hyperbranched polyamides is done by extrusion, preferably by reactive extrusion.

31. The method according to any of the preceding claims 1 to 23, wherein the polymerisation of said amino acids into hyperbranched polyamides is done in two subsequent phases, said phases comprising extrusion, preferably reactive extrusion, and comprising a heating reaction, preferably in batch.

32. The method according to any of the preceding claims, wherein after the step of polymerizing said amino acids into hyperbranched polyamides, water is added for dissolving the hyperbranched polyamides.

33. A glue for bonding of plant material, e.g. plant particles, such as vegetable fibres and / or wood chips and / or wood pieces, into boards, wherein the glue comprises at least a first raw material comprising hyperbranched polyamides, characterized in that said first raw material is obtained from polymerisation of a fermentation broth comprising amino acids, wherein said first raw material further comprises one or more components of the following list:-a carbon source, such as carbohydrates;-a nitrogen source-dry cellular matter, for example remnants of micro-organisms-salts, such as potassium salts or magnesium salts;-enzymes excreted by micro-organisms during fermentation; and / orwherein said hyperbranched polyamides of said first raw material have incorporated 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.

34. A glue for bonding of plant material, e.g. plant particles, such as vegetable fibres and / or wood chips and / or wood pieces, into boards, optionally according to claim 33, wherein the glue comprises at least a first raw material comprising hyperbranched polyamides, wherein the first raw material is a raw material obtained from a method according to any of the claims 1 to 32.

35. The glue according to claim 33 or 34, wherein the glue, in addition to said first raw material, comprises one or more additional raw materials of the following list: -crosslinkers, wherein these crosslinkers are preferably selected from the group comprising polyketones, polyesters, isocyanate dispersions, a-dicarbonyls, epoxides, glyoxal and other aldehydes;-a carbohydrate-containing material;-additives, preferably chosen from the list of bases, salts, metal-containing components, thickeners;-a denaturated and / or fermented flour.

36. The glue according to any of the claims 33 to 35, wherein the glue, in addition to said first raw material, comprises at least a material comprising carbohydrates and / or comprising reaction products between carbohydrates and the first raw material, said carbohydrates comprising invert sugar, wherein preferably the weight percentage of said invert sugar upon the total weight of carbohydrates is at least 80 wt% preferably at least 90 wt%.

37. The glue according to any of the claims 33 to 36, wherein the glue, in addition to said first raw material, comprises additives for enhancing water resistance, said additives being chosen from the list of:-a silicon containing compound, such as fumed silica or silanes or polysiloxanes;-a metallic soap;-a thermoplastic material;-inorganic fillers such as CaCCh, talc, vermiculite;-moisture absorbing material;-thermo-initiator;-epoxy;-zero-poisson’s ratio material.

38. 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 a glue that comprises a first raw material comprising hyperbranched polyamides, characterized in that said first raw material is a raw material obtained by a method according to any of the preceding claims 1 to 30 and / or said glue is a glue according to any of the preceding claims 31 to 37.

39. A laminate comprising two or more sheets, said laminate preferably comprising at least two or more paper sheets, and a cured glue that bonds at least two sheets of said two or more sheets to each other, wherein the cured glue is obtained by the curing of a glue that comprises a first raw material comprising hyperbranched polyamides, characterized in that said first raw material is a raw material obtained by a method according to any of the preceding claims 1 to 30 and / or said glue is a glue according to any of the preceding claims 31 to 37.