New latent hardeners and pu compositions containing them

Abstract

The present invention is directed to a latent hardener, preferably an aldimine or oxazolidine, which is obtainable by a process comprising the reaction of hydroxymethylfurfural or a derivative thereof and at least one amine A having at least one amino group and a process for the preparation of a latent hardener comprising reacting hydroxymethylfurfural or a derivative thereof and at least one amine A having at least one amino group. Furthermore, the present invention is directed to the use of the compounds according to the present invention as a hardener, in particular to a method comprising latently hardening compositions containing a prepolymer selected from the group consisting of an epoxy compound, an acrylate compound, an isocyanate compound, or an anhydride compound with at least one latent hardener according to the present invention.

Description

[0001] New latent hardeners and PU compositions containing them

[0002] The present invention is directed to latent hardener, preferably an aldimine or an oxazolidine which is obtainable by a process comprising the reaction of hydroxymethylfurfural or a derivative thereof and at least one amine A having at least one amino group and a process for the preparation of a latent hardener comprising reacting hydroxymethylfurfural or a derivative thereof and at least one amine A having at least one amino group. Furthermore, the present invention is directed to the use of the latent hardener according to the present invention as a hardener, in particular to a method comprising latently hardening compositions containing a prepolymer selected from the group consisting of an isocyanate compound, an epoxy compound, an acrylate compound, or an anhydride compound with at least one latent hardener according to the present invention.

[0003] Typically, adhesives and sealants, in particular adhesives and sealants based on polyurethanes are cured via the reaction of the terminal reactive groups, for example isocyanate groups of the polyurethane isocyanate prepolymer, with moisture. The problem is the side product, carbon dioxide, produced in the reaction of water and isocyanate, which results in bubble formation and pin-holing defects that can compromise the integrity and adhesion strength of the finished product.

[0004] An effective way to eliminate gassing and get bubble free films as well as to improve the cure performance is to introduce a latent hardener. Latent hardeners are chemically blocked amines which are activated by moisture, thereby releasing the curing agent. The free amine represents a fast reaction partner for the prepolymer, suppressing the direct reaction with moisture and thus formation of CO2. Especially suitable as latent hardeners are substances containing imine or oxazolidine moieties. Many monomers and prepolymers can be cured or cross-linked by amines. Examples of such amine-curable materials include the various acrylates, epoxides, urethanes, anhydrides and the like.

[0005] Commercially available latent aldimine hardeners have found use in elastic sealants and adhesives but have serious disadvantages. Due to the blocking agent used, volatile aldehydes are formed which are responsible for VOC emissions and odor. The strong odors are particularly disturbing. Examples of commercially available aldimines are for example disclosed in US 3932357, US 4469831 , or US 6136942. The use of oxazolidines as latent hardener is for example disclosed in WO 2020 / 126841 .

[0006] To avoid these disadvantages, in particular the strong odors, hardeners that consist of aliphatic imines derived from fatty acid esters were developed. They are described for example in: W02004 / 013088, EP 1775284, or EP 1384735. Aromatic aldimines and their use as latent hardeners are disclosed in WO 2017 / 108827. However, the syntheses disclosed in the state of the art are complicated and also the stability of the compositions disclosed is not sufficient for many applications. Accordingly, it was an objective to provide compounds which can be used as latent hardeners for adhesives without releasing odorous side products and which have an improved storage stability.

[0007] According to the present invention, this objective is solved by a latent hardener, in particular an aldimine or oxazolidine which is obtainable by a process comprising the reaction of hy- droxym ethylfurfural or a derivative thereof and at least one amine A having at least one amino group.

[0008] According to a further embodiment, the present invention is directed to the latent hardener, wherein the hardener is an aldimine or oxazolidine.

[0009] It has been surprisingly found that the latent hardeners, in particular the aldimines and oxazoli- dines according to the present invention can be easily prepared from readily available starting materials. Furthermore, the latent hardeners according to the present invention are stable under inert atmosphere at room temperature for a sufficient time. It has been found that the aldimines with hydroxyl group or with urethane or ether rests are very stable even without inert atmosphere. Aldimines with ester groups are stable up to certain extent and the storage stability of a composition comprising the aldimine according to the present invention and reactive components is also sufficiently storage stable for the application as an adhesive or sealant. Surprisingly, largely bubble-free curing without emission and odor can be achieved using these latent hardeners.

[0010] A substance or composition is referred to as “storage-stable” or “storable” when it can be stored at room temperature in a suitable container over a prolonged period, typically over at least 3 months to up to 6 months or more, without any change in its application or use properties to a degree of relevance for the use thereof as a result of the storage.

[0011] According to the present invention, the latent hardener is obtainable by a process comprising the reaction of hydroxym ethylfurfural or a derivative thereof and at least one amine A having at least one amino group. Advantageously, 5-Hydroxymethylfurfural (HMF) is a bio-based monomer.

[0012] Suitable amines A are in principle known to the person skilled in the art. Preferred amines A for the preparation of aldimines are for example aliphatic or cycloaliphatic primary mono-, di- or triamines, especially hexamethylene-1 ,6-diamine, isophoronediamine, a,uj-polyoxypropylenedia- mines having an average molecular weight in the range from 200 to 4000 g / mol, a,uj-polyoxypro- pylene-oxyethylenediamines having an average molecular weight in the range from 200 to 4000 g / mol, or glycerol or trimethylolpropane-started amines such as tris(uj-polyoxypropyleneamine) having an average molecular weight in the range from 300 to 5000 g / mol.

[0013] According to a further embodiment, the present invention is also directed to the aldimine as disclosed above, wherein the amine A has 1 to 4 or preferably 2 to 3 amino groups. Suitable amines for the preparation of aldimines may have a molecular weight of up to 6000 g / mol, preferably in the range of from 30 to 5000 g / mol, more preferable in the range of from 100 to 2000 g / mol, in particular in the range of from 200 to 1000 g / mol.

[0014] Preferably, aliphatic amines such as aliphatic amines with 1 to 4 amino groups, in particular mono-, di-or triamines are used. Therefore, according to a further embodiment, the present invention is also directed to the aldimine as disclosed above, wherein the amine is an aliphatic amine. Suitable amines are for example aliphatic polyamines such as ethylenediamine, 1 ,2- and

[0015] 1 .3-propanediamine, 2-methyl-1 ,2-propanediamine, 2,2-dimethyl-1 ,3-propanediamine, 1 ,3- and

[0016] 1 .4-butanediamine, 1 ,3- and 1 ,5-pentanediamine, 1 ,6-hexanediamine, 2,2,4- and 2,4,4-trime- thylhexamethylenediamine and mixtures thereof, 1 ,7-heptanediamine, 1 ,8-octanediamine, 4- aminomethyl-1 ,8-octanediamine, 1 ,9-nonanediamine, 1 ,10-decanediamine, 1 ,11-undecanedia- mine, 1 ,12-dodecanediamine, methylbis(3-aminopropyl)amine, 1 ,5-diamino-2-methylpentane (MPMD), 1 ,3-diaminopentane (DAMP), p-xylenediamine, m-xylenediamine, o-xylanediamine,

[0017] 2.5-dimethyl-1 ,6-hexamethylenediamine, cycloaliphatic polyamines such as 1 ,2-, 1 ,3- and 1 ,4- diaminocyclohexane, bis(4-aminocyclohexyl)methane, bis(4-amino-3-methylcyclohexyl)me- thane, bis(4-amino-3-ethylcyclohexyl)methane, bis(4-amino-3,5-dimethylcyclohexyl)methane, 1- amino-3-aminomethyl-3,5,5-trimethylcyclohexane (=isophoronediamine or I PDA), 2- and 4-me- thyl-1 ,3-diaminocyclohexane and mixtures thereof, 1 ,3- and 1 ,4-bis(aminomethyl)cyclohexane,

[0018] 1 -cyclohexylamino-3-aminopropane, 2,5(2,6)-bis(aminomethyl)bicyclo[2.2.1 Jheptane (N BDA), 3(4),8(9)bis(aminomethyl)tricyclo[5.2.1 ,0<2,6> Jdecane, 1 ,4-diamino-2,2,6-trimethylcyclohexane (TMCDA), 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, 1 ,3- and 1 ,4-xylylenedi- amine, aliphatic polyamines containing ether groups such as bis(2-aminoethyl)ether, 4,7-dioxa- decane-1 ,10-diamine, 4,9-dioxadodecane-1 ,12-diamine and higher oligomers thereof, 1 ,8-dia- mino- -menthane, 4,4’-diaminodicyclohexylmethane, tris(2-aminoethyl)amine, 4,7,10-trioxa- 1 ,13- tridecanediamine; polyoxyalkylene-polyamines having in theory two or three amino groups, obtainable for example under the name Jeffamine® (manufactured by Huntsman Chemicals) such as JEFFAMINE® diamines (D-230, D-400, D-2000, D-4000), JEFFAMINE® ED Series (ED-600, ED-900, ED-2003), JEFFAMINE® THF Series (THF-100, THF-170), JEFFAMINE® T Series (T-403, T-3000, T-5000), Jeffamine EDR series such as JEFFAMINE® EDR-148 or JEFFAMINE® EDR-176 and also mixtures of the aforementioned polyamines. Suitable are also monoamines with a molecular weight of up to 6000 g / mol, preferably in the range of from 30 to 5000 g / mol, more preferable in the range of from 100 to 2000 g / mol, in particular in the range of from 200 to 1000 g / mol. Preferable monoamines are ethylamine, propylamine, n- butylamine, t-butylamine, hexylamine, octylamine, tridecylamine, dodecylamine, 2-phenylethyla- mine, benzylamine, furfurylamine, 2-ethylhexylamine and Jeffamine M series such as JEFFAMINE® M-600, M-2005, M-1000, M-2070, M-2095 and M-3085. According to a further embodiment, mixtures of two or more amines A can be used.

[0019] Preferable are also amino alcohols with a molecular weight of up to 6000 g / mol, preferably in the range of from 30 to 5000 g / mol, more preferable in the range of from 50 to 2000 g / mol, in particular in the range of from 100 to 1000 g / mol. Preferable amino alcohols are ethanolamine, 3-amino-1 -propanol, 4-amino-1 -butanol, 5-amino-1 -pentanol, isopropanolamine, 2-(2-aminoeth- oxy)ethanol, aminomethylpropanol, 2-amino-3-methylbutan-1-ol, 2-amino-2-methyl-1 -propanol, 3-amino-1 ,2-propanediol, serinol, 2-amino-2-methyl-1 ,3-propanediol, 2-amino-2-ethyl-1 ,3-pro- panediol, 6-amino-2-hydroxymethyl hexan-1-ol.

[0020] Also cycloaliphatic or aromatic amines may be used according to the present invention. Suitable amines are for example 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane (isophoronediamine or I PDA), 1 ,8-diamino- / j-menthane, 1 ,2-diaminocyclohexane, 1 ,3-diaminocyclohexane, 1 ,4-diaminocyclohexane and 4,4’-diaminodicyclohexylmethane. Also aromatic amines such as naphthalene diamines, for example 1 ,5-diaminonaphthalene, methylene diphenyl diamines such as 4,4’-diaminodiphenylmethane, toluenediamines such as 2,4-diaminotoluene and 2,6-dia- minotoluene, p-phenylenediamine, o-phenylenediamine, m-phenylenediamine. According to a further embodiment, mixtures of two or more amines A can be used.

[0021] Preferred amines A for the preparation of oxazolidines are for example aliphatic or cycloaliphatic P-aminoalcohol having an average molecular weight in the range from 50 to 1000 g / mol. Suitable aminoalcohols are in principle known to the person skilled in the art. Suitable amino alcohols may be selected from the group of N-methylethanolamine, N-ethylethanolamine, N-n-propylethanola- mine, N-isopropylethanolamine, N-n-butylethanolamine, N-isobutylethanolamine, N-2-butyleth- anolamine, N-tert-butylethanolamine, N-n-hexylethanolamine, N-isohexylethanolamine, N-(2- ethylhexyl)ethanolamine, N-cyclohexylethanolamine or N-benzylethanolamine, especially N- methylethanolamine, N-ethylethanolamine, N-n-butylethanolamine or N-benzylethanolamine. Particular preference is given to N-n-butylethanolamine. Preferably diethanol amine or 2-(methyl- amino)ethan-1-ol may be used in the context of the present invention.

[0022] According to a further embodiment, the present invention is also directed to the oxazolidine as disclosed above, wherein the amine A is a p-aminoalcohol.

[0023] According to the present invention, derivatives of hydroxymethylfurfural may be used, such as for example ethers, esters and urethanes of hydroxymethylfurfural. In the context of the invention, ethers, esters or urethanes of hydroxymethylfurfural are understood to be derivatives wherein the hydroxy group of the hydroxymethylfurfural has reacted to form an ether group, ester group or urethane group.

[0024] According to a further embodiment, the present invention is also directed to the latent hardener as disclosed above, wherein the derivative of hydroxy methylfurfural is selected from the group consisting of ethers, esters and urethanes.

[0025] Suitable compounds and reaction conditions for forming the derivatives of hydroxymethylfurfural are in principle known to the person skilled in the art. Preferably, the ethers, esters and urethanes of hydroxy methylfurfural have linear or branched C1-C36 alkyl chains and may have further functional groups such as for example one or more OH or NH2 groups. Suitable are also compounds having one or more SH groups or double bonds, in particular curable double bonds. Also aromatic compounds with or without functional groups can be used according to the present invention.

[0026] According to a further embodiment, the present invention is also directed to the latent hardener as disclosed above, wherein the derivative of hydroxym ethylfurfural is selected from the group consisting of ethers, esters and urethanes having linear or branched C4-C36 alkyl chains, optionally having one or more OH or NH2 end groups.

[0027] According to a further embodiment, the present invention is also directed to the latent hardener as disclosed above, wherein the latent hardener has the general formula (I), in particular (I*): wherein

[0028] A is selected from the group consisting of -O-, -O(CO)-, and -O(CO)NH- groups,

[0029] R° is H or a linear or branched or cyclic alkylene chain or arylalkyl residue, preferably having 2 to 300 carbon atoms, more preferable alkyl or cycloalkyl or arylalkyl residue having 1 to 40 C atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen and optionally one or more functional groups and

[0030] R is a linear or branched or cyclic alkylene chain, preferably having 2 to 300 carbon atoms, more preferable having 2 to 40 carbon atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen, or for a singly or multiply unsaturated linear or branched or cyclic hydrocarbon chain, preferably having 2 to 16 carbon atom, and n is 2, 3, 4, 5, or 6, preferably 2, 3 or 4, more preferably 2 or 3, in particular 2.

[0031] According to a further embodiment, R may contain aromatic groups. Furthermore, R can be the -N-N- rest, obtained in the reaction of hydroxymethylfurfural or derivative of hydroxymethylfurfural with hydrazine.

[0032] The present invention is also directed to compounds having one aldimine group and optionally further reactive functional groups. According to a further embodiment, the present invention is also directed to the latent hardener as disclosed above, wherein the latent hardener has the general formula (II): wherein

[0033] A is selected from the group consisting of -O-, -O(CO)-, and -O(CO)NH- groups, R° is H or a linear or branched or cyclic alkylene chain or arylalkyl residue, preferably having 2 to 300 carbon atoms, more preferable alkyl or cycloalkyl or arylalkyl residue having 1 to 40 C atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen and optionally one or more functional groups and

[0034] X is a linear or branched or cyclic alkylene chain, having 2 to 40 carbon atoms, optionally having one or more reactive functional groups, preferable hydroxyl group or amino group, more preferable hydroxyl group, if desired having at least one heteroatom, in particular having at least one ether oxygen, or for a singly or multiply unsaturated linear or branched or cyclic hydrocarbon chain having 2 to 16 carbon atom.

[0035] According to a further embodiment, the present invention is also directed to the latent hardener as disclosed above, wherein the latent hardener has the general formula (III): wherein

[0036] A is selected from the group consisting of -O-, -O(CO)-, and -O(CO)NH- groups,

[0037] R° is H or a linear or branched or cyclic alkylene chain or arylalkyl residue, preferably having 2 to 300 carbon atoms, more preferable alkyl or cycloalkyl or arylalkyl residue having 1 to 40 C atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen and optionally one or more functional groups and

[0038] R1is an alkyl or cycloalkyl or arylalkyl radical, preferably having 1 to 8 carbon atoms, and may have at least one ether oxygen and / or further functional groups such as for example one or more OH or NH2 groups.

[0039] According to a further embodiment, the present invention is also directed to the latent hardener as disclosed above, wherein the latent hardener has the general formula (IV), preferably (IV*): wherein

[0040] A is selected from the group consisting of -O-, -O(CO)-, and -O(CO)NH- groups,

[0041] R1is an alkyl or cycloalkyl or arylalkyl radical, preferably having 1 to 8 carbon atoms, and may have at least one ether oxygen and / or further functional groups such as for example one or more OH or NH2 groups and

[0042] R is a linear or branched or cyclic alkylene chain, preferably having 2 to 300 carbon atoms, more preferable having 2 to 40 carbon atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen, or for a singly or multiply unsaturated linear or branched or cyclic hydrocarbon chain preferably having 2 to 16 carbon atom, and n is 2, 3, 4, 5, or 6, preferably 2, 3 or 4, more preferably 2 or 3, in particular 2.

[0043] R can be also rest containing one or more aromatic groups (for example obtained in the reaction with 4,4'-diphenylmethane diisocyanate or toluene-2,4-diisocyanate).

[0044] According to preferred embodiments, the latent hardener according to the present invention may have the general formula (la), (lb), (Ic) or (Id), preferably formula (la*), (lb*), (lc*) or (Id*). wherein

[0045] R stands for a linear or branched or cyclic alkylene chain, preferably having 2 to 300 carbon atoms, more preferable having 2 to 40 carbon atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen, or for a singly or multiply unsaturated linear or branched or cyclic hydrocarbon chain preferably having 2 to 16 carbon atoms, and R2, R3, R4independently is an alkyl or cycloalkyl or arylalkyl residue having 1 to 40 C atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen and optionally one or more functional groups. According to a further embodiment, R may contain aromatic groups and n is 2, 3, 4, 5, or 6, preferably 2, 3 or 4, more preferably 2 or 3, in particular 2.

[0046] Preferably R1, R2, R3, R4are independently linear or branched C1-C36 alkyl chains and may have further heteroatoms and / or functional groups, preferably one or more OH or NH2 groups.

[0047] R may for example be an alkyl residue or a branched residue with 2-40 C atoms, cycloalkyl residue with 6-40 C atoms, a polypropylene oxide (PPO) chain with a molecular weight Mw of from 200 to 5000 g / mol, a polyethylene oxide (PEO) chain with a molecular weight Mw of from 200 to 5000 g / mol, a PPO-PEO chain with a molecular weight Mw of from 200 to 5000 g / mol.

[0048] According to preferred embodiments, the latent hardener according to the present invention may have the general formula (Ila), (lib), (He) or (lid).

[0049] (Hd), wherein X stands for a linear or branched or cyclic alkylene chain, preferably having 2 to 300 carbon atoms, more preferable having 2 to 40 carbon atoms, having one or more reactive functional groups, preferable hydroxyl group, if desired having at least one heteroatom, in particular having at least one ether oxygen, or for a singly or multiply unsaturated linear or branched or cyclic hydrocarbon chain or a residue comprising aromatic groups, preferably having 2 to 16 carbon atoms, and

[0050] R2, R3, R4independently is an alkyl or cycloalkyl or arylalkyl residue having 1 to 40 C atoms and optionally one or more functional groups. Preferably R2, R3, R4independently linear or branched C1-C36 alkyl chains and may have further heteroatoms and / or functional groups, preferably one or more OH or NH2 groups.

[0051] X is a linear or branched or cyclic alkylene chain, preferably having 2 to 300 carbon atoms, more preferable having 2 to 40 carbon atoms, optionally having one or more reactive functional groups, preferable hydroxyl group or amino group, more preferable hydroxyl group, if desired having at least one heteroatom, in particular having at least one ether oxygen, or for a singly or multiply unsaturated linear or branched or cyclic hydrocarbon chain preferably having 2 to 16 carbon atoms.

[0052] X may for example be an alkyl residue with 2-40 C atoms, cycloalkyl residue with 6-40 C atoms, a PPO chain with a molecular weight Mw of from 200 to 5000 g / mol, a PEO chain with a molecular weight Mw of from 200 to 5000 g / mol, a PPO-PEO chain with a molecular weight Mw of from 200 to 5000 g / mol.

[0053] According to a further embodiment, the latent hardener according to the present invention may have the general formula (Illa), (I I lb), (I I Ic) or (Hid). wherein R1, R2, R3, R4independently is an alkyl or cycloalkyl or arylalkyl residue having 1 to 40 C atoms and optionally one or more functional groups. Preferably R1, R2, R3, R4independently linear or branched C1-C36 alkyl chains and may have further heteroatoms and / or functional groups, preferably one or more OH or NH2 groups.

[0054] According to a further embodiment, the latent hardener according to the present invention may have the general formula (IVa), (IVb), or (IVc), in particular (IVa*), (IVb*) or IVc*). wherein

[0055] R stands for a linear or branched or cyclic alkylene chain, preferably having 2 to 300 carbon atoms, more preferable having 1 to 40 carbon atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen, or for a singly or multiply unsaturated linear or branched or cyclic hydrocarbon chain preferably having 2 to 16 carbon atoms, according to a further embodiment, R may contain aromatic groups, and

[0056] R1independently is an alkyl or cycloalkyl or arylalkyl residue having 1 to 40 C atoms and optionally one or more functional groups, and n is 2, 3, 4, 5, or 6, preferably 2, 3 or 4, more preferably 2 or 3, in particular 2.

[0057] Preferably R1independently linear or branched C1-C36 alkyl chains and may have further heteroatoms and / or functional groups, preferably one or more OH or NH2 groups.

[0058] According to a further aspect, the present invention is directed to a process for the preparation of a latent hardener comprising step (i)

[0059] (i) reacting hydroxymethylfurfural or a derivative thereof and at least one amine A having at least one amino group.

[0060] According to the present invention, amine A comprises at least one amine group. According to the present invention, it is possible to use a monoamine in the process according to the invention and prepare a compound having one aldimine group. It is also possible to use an amine A having two or more amino groups thus resulting in a product having two or more aldimine groups. Suitable reaction conditions for the reaction according to step (i) are in principle known to the person skilled in the art. According to the present invention, it is possible to prepare the latent hardener according to the invention by first reacting the hydroxymethylfurfural with the at least one amine A to obtain a hydroxymethylfurfural derivative (HD1) with free OH groups which may then be reacted with a suitable compound with functional groups reactive to the free OH groups to form the latent hardener, in particular the oxazolidine or the aldimine or in an alternative embodiment, react hydroxymethylfurfural with a compound (01) having functional groups reactive towards OH groups to obtain a hydroxym ethylfurfural derivative (HD2) with a functionalized OH group which in turn is reacted with the amine A to obtain the latent hardener.

[0061] According to one embodiment, the present invention is also directed to the process as disclosed above, wherein the process comprises steps (i’) and (ii’)

[0062] (i’) reacting hydroxy methylfurfural and at least one amine A having at least one amino group to obtain a hydroxym ethylfurfural derivative (HD1) with free OH groups,

[0063] (ii’) reacting the hydroxymethylfurfural derivative (HD1) with a compound (C1) having functional groups reactive towards OH groups to obtain an aldimine.

[0064] Suitable reaction conditions are in principle known to the person skilled in the art. Step (i’) can for example be carried out at a temperature in the range from room temperature to 120°C, for example under solvent free conditions or in solution, preferable under the solvent free conditions, applying continuous vacuum in bulk reaction to remove water formed in this reaction.

[0065] Step (ii’) can for example be carried out using various conditions depending on the substituent. For example, the reaction with an isocyanate can be done at a temperature in the range of from 40-120° C in bulk or in solution, preferably in bulk. Optionally, a catalyst may be used, in particular a catalyst for the reaction of isocyanate with an alcohol can be used.

[0066] According to a further embodiment, the present invention is also directed to the process as disclosed above, wherein step (i) comprises steps (i.1) and (i.2)

[0067] (1.1) reacting hydroxy methylfurfural with a compound (C1) having functional groups reactive towards OH groups to obtain a hydroxymethylfurfural derivative (HD2) with a functionalized OH group,

[0068] (1.2) reacting the hydroxymethylfurfural derivative (HD2) obtained in step (i.1) with at least one amine A having at least one amino group to obtain an aldimine.

[0069] Suitable reaction conditions are in principle known to the person skilled in the art. In step (i.1) ester containing derivative can be prepared by reacting hydroxy methylfurfural with an acylchloride for example carried out in solution at RT using base as a catalyst, followed by the evaporation of the solvent. For the preparation of an ether, it is possible to react HMF with, for example, a monoalcohol, using a heterogeneous catalyst for etherification reaction in bulk at a temperature of about 100°C. The catalyst can be removed by filtration.

[0070] For the formation of a urethane, it is possible to react a mono- or polyisocyanate (aliphatic or aromatic) in solution at a temperature in the range from room temperature to 80°C and the solvent can be removed at the end of the reaction.

[0071] Step (i.2) can for example be carried out at a temperature in the range from room temperature to 120°C, for example under solvent free conditions or in solution, preferable under the solvent free conditions, applying continuous vacuum in bulk reaction to remove water formed in this reaction.

[0072] According to a further embodiment, the present invention is also directed to the process as disclosed above, wherein step (i) comprises steps (i.a) and (i.b)

[0073] (i.a) reacting hydroxy methylfurfural with a compound (C1) having functional groups reactive towards OH groups to obtain a hydroxymethylfurfural derivative (HD2) with a functionalized OH group,

[0074] (i.b) reacting the hydroxym ethylfurfural derivative (HD2) obtained in step (i.1 ) with at least one amine A having at least one amino group to obtain an oxazolidine.

[0075] Suitable reaction conditions are in principle known to the person skilled in the art. According to step (i.a), the ester containing derivative can be prepared by reacting hydroxy methylfurfural with an acylchloride for example carried out in solution at RT using base as a catalyst, followed by the evaporation of the solvent. For the preparation of an ether, it is possible to react HMF with for example a monoalcohol, using a heterogeneous catalyst for etherification reaction in bulk at a temperature of about 100°C. The catalyst can be removed by filtration. For the formation of a urethane, it is possible to react a mono- or polyisocyanate (aliphatic or aromatic) in solution at a temperature in the range from room temperature to 80°C and the solvent can be removed at the end of the reaction.

[0076] Step (i.b) can for example be carried out at a temperature in the range of from 40-120 °C in bulk (or in solution), applying vacuum to remove water. Suitable solvents are in principle known to the person skilled in the art.

[0077] Suitable compounds (C1) are for example acids and derivatives thereof such as acetic acid, propionic acid, butyric acid, valeric acid, 2-ethylhexanoic acid, i-nonanoic acid, isononanoic acid, caproic acid, caprylic acid, capric acid, lauric acid, palmitic acid, stearic acid, oleic acid, linoleic acid, acetyl chloride, propionyl chloride, butyryl chloride, benzoyl chloride, valeryl chloride, caproyl chloride, stearyl chloride, palmitoyl chloride, lauroyl chloride, oleoyl chloride, linoleoyl chloride, methyl acetate, methyl propionate, methyl butyrate, methyl valerate, methyl hexanoate, methyl benzoate, methyl salicylate, methyl laurate, methyl stearate, methyl oleate, methyl linoleate, tridecanoic acid, myristic acid, pentadecanoic acid, margaric acid, stearic acid, nonadecanoic acid, arachidic acid, palmitoleic acid, oleic acid, erucic acid, linoleic acid, eleostearic acid, arachidonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1 ,12-dodecanedioic acid, maleic acid, fumaric acid, hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, 3,6,9-trioxaundecanedioic acid and similar derivatives of polyethylene glycol, dehydrogenated ricinoleic acids, and also fatty acids from the industrial saponification of natural oils and fats such as, for example, rapeseed oil, sunflower oil, linseed oil, olive oil, coconut oil, oil palm kernel oil and oil palm oil.

[0078] Furthermore, in the context of the present invention, also compounds (C1 ) may be used having one functional group reactive towards OH groups such as for example mono-isocyanates such as phenyl isocyanate, p-tolylisocyanate, n-hexylisocyanate, butylisocyanate, n-dodecylisocya- nate, m-tolylisocyanate.

[0079] Suitable alcohols as compound C1 are for example mono-alcohols such as methanol, ethanol, propanol, butanol, hexan-1-ol, octan-1-ol, decan-1 -ol, dodecan-1-ol.

[0080] Furthermore, in the context of the present invention, suitable compounds (C1) are for example also difunctional or higher functional acids, esters, acid chlorides, or also diols and isocyanates such as di-carboxylicacids, for example adipic acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, sebacic acid, malonic acid, glutaric acid, azelaic acid, dodecanedioic acid, maleic acid, fumaric acid, itaconic acid, tri-carboxylic acids such as citric acid, di-acyl chlorides, for example phthaloyl chloride, succinyl chloride, adipoyl chloride, sebacoyl chloride, glutaroyl chloride, malonyl chloride, suberoyl chloride, azelaoyl chloride, dodecanedioyl dichloride, isophthaloyl chloride, terephthaloyl chloride, itaconyl chloride, maleoyl chloride, diols such as ethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, trimethylene glycol, decanediol, dodecanediol, 1 ,4-cyclohexanedimethanol, polyethylene glycol (PEG). Also diisocyantes may be used in the context of the present invention such as for example toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), methylenediphenyl diisocyanate (MDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate, naphthalene diisocyanate (NDI), polymethylene polyphenyl isocyanate (PMDI), dicyclohexylmethane diisocyanate (HMDI), trimethylhexamethylene diisocyanate (TMHDI), tetramethylxylene diisocyanate (TMXDI), 4,4'-methylenebis(cyclohexyl isocyanate) (H 12MDI). Furthermore, trimers of TDI, MDI, HDI may be used.

[0081] According to the present invention, it is also possible to prepare a latent hardener having two or more oxazolidine groups. It is for example possible to react hydroxy methylfurfural with a suitable compound having two or more functional groups reactive towards OH groups and then prepare the respective oxazolidine.

[0082] Therefore, according to a further embodiment, the present invention is also directed to a process as disclosed above, wherein step (i) comprises steps (i.X) and (i.Y): (i.X) reacting hydroxymethylfurfural with a compound (C2) having ate least two functional groups reactive towards OH groups to obtain a hydroxy methylfurfural derivative (HD3) with a functionalized OH group,

[0083] (i.Y) reacting the hydroxymethylfurfural derivative (HD3) obtained in step (i.X) with at least one amine A having at least one amino group to obtain an oxazolidine.

[0084] Suitable reaction conditions are in principle known to the person skilled in the art. In step (i.X) ester containing derivative can be prepared by reacting hydroxymethylfurfural with two or higher functional acylchloride for example carried out in solution at RT using base as a catalyst, followed by the evaporation of the solvent.

[0085] For the preparation of an ether, it is possible to react HMF with a two- or higher functional alcohol, using a heterogeneous catalyst for etherification reaction in bulk at a temperature of about 100°C. The catalyst can be removed by filtration.

[0086] For the formation of a urethane, it is possible to react two or higher functional isocyanate (aliphatic or aromatic) in solution at a temperature in the range from room temperature to 80°C and the solvent can be removed at the end of the reaction.

[0087] Step (i.Y) can for example be carried out at a temperature in the range from room temperature to 120°C, for example under solvent free conditions or in solution, preferable under the solvent free conditions, applying continuous vacuum in bulk reaction to remove water formed in this reaction.

[0088] Suitable compounds (C2) are for example difunctional or higher functional acids, esters, acid chlorides, or also diols and isocyanates such as di-carboxylicacids, for example adipic acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, sebacic acid, malonic acid, glutaric acid, azelaic acid, dodecanedioic acid, maleic acid, fumaric acid, itaconic acid, tri-carbox- ylic acids such as citric acid, di-acyl chlorides, for example phthaloyl chloride, succinyl chloride, adipoyl chloride, sebacoyl chloride, glutaroyl chloride, malonyl chloride, suberoyl chloride, azelaoyl chloride, dodecanedioyl dichloride, isophthaloyl chloride, terephthaloyl chloride, ita- conyl chloride, maleoyl chloride, diols such as ethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, trimethylene glycol, decanediol, dodecanediol, 1 ,4-cyclohexanedimethanol, polyethylene glycol (PEG). Also diisocyantes may be used in the context of the present invention such as for example toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), methylenediphenyl diisocyanate (MDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate, naphthalene diisocyanate (NDI), polymethylene polyphenyl isocyanate (PM DI), dicyclohexylmethane diisocyanate (HMDI), trimethylhexamethylene diisocyanate (TMHDI), tetramethylxylene diisocyanate (TMXDI), 4,4'-meth- ylenebis(cyclohexyl isocyanate) (H12MDI). Furthermore, trimers of TDI, MDI, HDI may be used.

[0089] It has been found that the latent hardeners according to the present invention are particularly suitable as hardeners for compositions containing reactive monomers or prepolymers such as monomers or prepolymers comprising isocyanate groups, epoxy groups, acrylate groups, or anhydride groups. Also prepolymers comprising modified isocyanate groups may be used.

[0090] Therefore, according to a further aspect, the present invention is directed to a composition comprising

[0091] (a) at least one latent hardener according to the present invention, and

[0092] (b) at least one monomer or prepolymer selected from the group consisting of an isocyanate compound, epoxy compound, an acrylate compound, or an anhydride compound.

[0093] According to the present invention, the amounts of the latent hardener and the monomer or prepolymer in the composition may vary in broad ranges. Suitable amounts are in principle known to the person skilled in the art. The composition may for example comprise the monomer or prepolymer in an amount of at least 70% by weight, preferably at least 80% by weight and in particular at least 90% by weight based on the weight of the composition. The composition may comprise the latent hardener, in particular the aldimine or the oxazolidine in an amount of from 0.5 to 30 wt%, more preferable in the range from 1 to 20 wt%, even more preferable in the range from 1 to 15 wt% and the most preferable in the range from 3 to 10 wt%.

[0094] Suitable monomers or prepolymers are in particular monomers and prepolymers having isocyanate groups. In the context of the invention, the isocyanate-terminated prepolymer preferably is the reaction product of diisocyanates with compounds that have at least two isocyanate-reactive groups and optionally with compounds having one isocyanate-reactive group, with the diisocyanate being used in excess. Suitable monomers and prepolymers are in principle known to the person skilled in the art.

[0095] All aliphatic, cycloaliphatic, and aromatic difunctional isocyanates known from the prior art and any mixtures thereof may be used as the diisocyanates for the production of the isocyanate- containing prepolymer. Isocyanate-reactive compounds having at least two isocyanate-reactive groups used for the production of the isocyanate-containing prepolymer may be any compounds having at least two isocyanate-reactive groups. Preference is given to using polyesterols, polyetherols or polyether-polyesterols that may be obtained, for example, by alkoxylation of polyesters, in particular polyesterols.

[0096] According to a further embodiment, the present invention is also directed to the composition as disclosed above, wherein the composition comprises at least one polyurethane polymer containing isocyanate groups.

[0097] A suitable polyurethane polymer containing isocyanate groups is especially obtained from the reaction of at least one polyol with at least one polyisocyanate. The reaction is preferably conducted with exclusion of moisture at a temperature in the range from 50 to 160 °C, optionally in the presence of suitable catalysts. The NCO / OH ratio is preferably in the range froml . 1 .3 / 1 to 2.5 / 1 . The polyisocyanate remaining after the conversion of the OH groups in the reaction mixture, especially monomeric diisocyanate, can be removed, especially by means of distillation, which is preferable in the case of a high NCO / OH ratio. The polyurethane polymer obtained preferably has a content of free isocyanate groups in the range from 0.5% to 10% by weight, especially 1 % to 5% by weight, more preferably 1 % to 3% by weight. The polyurethane polymer can optionally be prepared with additional use of plasticizers or solvents, in which case the plasticizers or solvents used do not contain any groups reactive toward isocyanates.

[0098] The polyurethane prepolymer typically is prepared using commercially customary polyisocyanates. Examples that may be mentioned include the following polyisocyanates, which are very well known within polyurethane chemistry, such as: 2,4- and 2,6-tolylene diisocyanate (TDI) and any desired mixtures of these isomers, 4,4'-diphenylmethane diisocyanate (MDI), the position- ally isomeric diphenylmethane diisocyanates, 1 ,3- and 1 ,4-phenylene diisocyanate, 2,3,5,6-tet- ramethyl-1 ,4-diisocyanatobenzene, 1 ,6-hexamethylene diisocyanate (HDI), 2-methylpentameth- ylene 1 ,5-diisocyanate, 2,2,4- and 2, 4, 4-trimethyl-1 ,6-hexamethylene diisocyanate (TMDI), dodecamethylene 1 ,12-diisocyanate, cyclohexane 1 ,3- and 1 ,4-diisocyanate and any desired mixtures of these isomers, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate or IPDI), perhydro-2,4'- and -4,4'-diphenylmethane diisocyanate (HMDI), 1 ,4- diisocyanato-2,2,6-trimethylcyclohexane (TMCDI), m- and p-xylylene diisocyanate (XDI), tetramethylxylylene 1 ,3- and 1 ,4-diisocyanate (TMXDI), 1 ,3- and 1 ,4-bis(isocyanatomethyl)cyclohex- ane, and also oligomers and polymers of the aforementioned isocyanates, and also any desired mixtures of the aforementioned isocyanates. Particular preference is given to MDI, TDI, HDI and IPDI.

[0099] Suitable polyols are commercial polyols or mixtures thereof.

[0100] In addition, the composition according to the invention may comprise further additives, depending on the application of the composition, such as for example surface-active substances, for example mold-release agents and / or defoamers, inhibitors such as diglycol bis(chloroformate) or orthophosphoric acid, plasticizers, inorganic and / or organic fillers such as sand, kaolin, chalk, barium sulfate, silica, and carbon black, oxidation stabilizers, melt auxiliaries such as thermoplastic polymers, dyes and pigments, stabilizers, for example against hydrolysis, light, heat or discoloration, emulsifiers, flame retardants, aging stabilizers, and adhesion promoters, and also catalysts typically used in polyurethane chemistry .

[0101] According to a further embodiment, the present invention is also directed to the composition as disclosed above, wherein the composition additionally comprises at least one further constituent selected from catalysts, fillers, plasticizers and solvents.

[0102] Suitable catalysts are especially catalysts for the hydrolysis of the aldimine groups, especially organic acids, especially carboxylic acids such as 2-ethylhexanoic acid, lauric acid, stearic acid, isostearic acid, acetic acid, oleic acid, neodecanoic acid, benzoic acid, salicylic acid or 2-nitro- benzoic acid, organic carboxylic anhydrides such as phthalic anhydride, hexahydrophthalic anhydride or methylhexahydrophthalic anhydride, silyl esters of carboxylic acids, organic sulfonic acids such as methanesulfonic acid, p-toluenesulfonic acid or 4-dodecylbenzenesulfonic acid, sulfonic esters, other organic or inorganic acids, or mixtures of the aforementioned acids and acid esters. Particular preference is given to carboxylic acids, especially aromatic carboxylic acids such as benzoic acid, or salicylic acid.

[0103] Suitable catalysts are additionally catalysts for the acceleration of the reaction of isocyanate groups, especially organotin(IV) compounds such as, in particular, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, dibutyltin diacetylacetonate, dimethyltin dilaurate, dioctyltin diacetate, dioctyltin dilaurate or dioctyltin diacetylacetonate, complexes of bismuth(lll) or zirco- nium(IV), especially with ligands selected from alkoxides, carboxylates, 1 ,3-diketonates, ox- inate, 1 ,3-ketoesterates and 1 ,3-ketoamidates, or compounds containing tertiary amino groups, such as, in particular, catalysts customary in polyurethane chemistry, for example 1 ,4-diazabicy- clo[2.2.2]octane (DABCO) or dimethylcyclohexylamin.

[0104] Also especially suitable are combinations of different catalysts.

[0105] Suitable fillers are especially ground or precipitated calcium carbonates, optionally coated with fatty acids, especially stearates, or barytes, quartz flours, quartz sands, dolomites, wollastonites, kaolins, calcined kaolins, sheet silicates such as mica or talc, zeolites, aluminum hydroxides, magnesium hydroxides, silicas including finely divided silicas from pyrolysis processes, cements, gypsums, fly ashes, industrially produced carbon blacks, graphite, metal powders, for example of aluminum, copper, iron, silver or steel, PVC powders or hollow beads.

[0106] Suitable plasticizers are especially carboxylic esters such as phthalates, especially diisononyl phthalate (DINP), diisodecyl phthalate (DIDP) or di(2-propylheptyl) phthalate (DPHP), hydrogenated phthalates, especially hydrogenated diisononyl phthalate (DINCH), terephthalates, especially dioctyl terephthalate, trimellitates, adipates, especially dioctyl adipate, azelates, sebacates, benzoates, glycol ethers, glycol esters, organic phosphoric or sulfonic esters, polybutenes, polyisobutenes, or plasticizers derived from natural fats or oils, especially epoxidized soybean oil or linseed oil.

[0107] Suitable solvents are especially acetone, methyl ethyl ketone, methyl n-propyl ketone, diisobutyl ketone, methyl isobutyl ketone, methyl n-amyl ketone, methyl isoamyl ketone, acetylacetone, mesityl oxide, cyclohexanone, methylcyclohexanone, ethyl acetate, propyl acetate, butyl acetate, n-butyl propionate, diethyl malonate, 1 -methoxy-2-propyl acetate, ethyl 3-ethoxypropio- nate, diisopropyl ether, diethyl ether, dibutyl ether, diethylene glycol diethyl ether, ethylene glycol diethyl ether, ethylene glycol monopropyl ether, ethylene glycol mono-2-ethylhexyl ether, THF, DMF, toluene, xylene, heptane, octane, naphtha, white spirit, petroleum ether or benzine, especially Solvesso™ products (from Exxon), and also methylene chloride, propylene carbonate, butyrolactone, N-methylpyrrolidone or N-ethylpyrrolidone. The composition may comprise further additives commonly used for polyurethane compositions such as for example inorganic or organic pigments, fibers, dyes, desiccants, adhesion promoters, further latent hardeners or crosslinkers, rheology modifiers, flame-retardant substances, additives, especially wetting agents, leveling agents, defoamers, deaerators, stabilizers against oxidation, heat, light or UV radiation, or biocides, or further substances customarily used in moisture-curing compositions.

[0108] The composition is preferably produced with exclusion of moisture and stored at ambient temperature in moisture-tight containers. The composition can be formulated such that it has a pasty consistency with structurally viscous properties.

[0109] The composition is preferably applied at ambient temperature, especially in the range from about 0 to 50° C, preferably in the range from 5 to 40°C. The composition is preferably likewise cured at ambient temperature.

[0110] The composition is preferably used as an adhesive or a sealant or a coating. It has been found that the curing time can be improved using the latent hardeners according to the present invention. It has also been found that the aldimines according to the present invention also improve the stability of prepolymers and no additional plasticizer has to be used. In many cases, the latent hardeners according to the present invention can be used as curing agents without further acid.

[0111] The composition is especially suitable as an adhesive and / or sealant for bonding and sealing applications, especially in the construction and manufacturing industries. As a coating, the composition is suitable for protection of floors or walls. It can also be used for repair purposes as seal or coating. Furthermore, the composition can be used for preparing elastomers or foams. In principle, it is also possible to include the latent hardener according to the present invention in a composition, for example a foam composition which may not react in the preparation process but only be activated at a later stage of the use of the foam.

[0112] According to a further embodiment, the present invention is therefor also directed to the composition as disclosed above, wherein the composition is an adhesive or a sealant or a composition for preparing a coating, an elastomer or a foam.

[0113] According to a further aspect, the present invention is directed to a method comprising latently hardening compositions containing a prepolymer selected from the group consisting of an epoxy compound, an acrylate compound, an isocyanate compound, or an anhydride compound with at least one latent hardener, preferably at least one aldimine or oxazolidine, according to the present invention.

[0114] Furthermore, the present invention is directed to a method comprising latently hardening compositions containing compounds with isocyanate groups or epoxy groups with at least one latent hardener, preferably at least one aldimine or oxazolidine according to the present invention. According to a further aspect, the present invention is directed to the use of a latent hardener, preferably an aldimine or an oxazolidine according to the present invention in a composition which comprise components that are reactive toward amines.

[0115] According to a further embodiment, the present invention is also directed to the use of a latent hardener, preferably an aldimine or an oxazolidine in a composition which comprise components that are reactive toward amine, characterized in that the components that are reactive toward amines are isocyanates.

[0116] The aldimines and oxazolidines according to the present invention can be used as latent hardener, for example to produce hardened epoxy resins, or hardened polyurethanes, such as moldings, composite materials, foams, or adhesives. Thus, according to a further embodiment, the present invention is also directed to the use of a latent hardener according to the present invention, in particular an aldimine or oxazolidine according to the present invention, in a composition which comprise components that are reactive toward amine, characterized in that the composition is used as an adhesive, sealant, coating, foam or covering.

[0117] The composition is especially suitable as an adhesive and / or sealant for bonding and sealing applications, especially in the construction and manufacturing industries or in cosumer articles or in motor-vehicle construction, especially for parquet bonding, installable component bonding, cavity sealing, assembly, module bonding, chassis bonding, glass bonding, join sealing or anchoring. Elastic bonds in motor vehicle construction are especially the attachment of parts such as plastic covers, battery elements, decorative strips, flanges, fenders, drivers' cabins or other installable components to the painted chassis of a motor vehicle, or the bonding of glass panes into the chassis, where the motor vehicles are especially automobiles, trucks, buses, rail vehicles or ships.

[0118] The composition is especially suitable as a sealant for the elastic sealing of all kinds of joins, seams or cavities especially of joins in construction such as dilatation joins or connection joins between components. A sealant having elastomeric properties is particularly suitable especially for the sealing of dilatation joins in built structures.

[0119] As a coating, the composition is suitable for protection of floors or walls, especially as coating of balconies, terraces, open spaces, bridges, parking decks, or for sealing of roofs, especially flat roofs or slightly inclined roof areas or roof gardens, or in the interior of buildings for water sealing, for example beneath tiles or ceramic plates in wet cells or kitchens, or as floorcovering in kitchens, industrial halls or fabrication spaces, or as seal in collection tanks, channels, shafts or wastewater treatment plants, or protection of surfaces as varnish or seal, or as potting compound for cavity sealing, as seam seal or as protective coating for pipes, for example.

[0120] It can also be used for repair purposes as seal or coating, for example of leaking roof membranes or floor coverings that are no longer fit for purpose, or more particularly as repair compound for highly reactive spray seals. The composition can be formulated such that it has a pasty consistency with structurally viscous properties. A composition of this kind is applied by means of a suitable device, for example from standard commercial cartridges or vats or hobbocks, for example in the form of a bead, which may have an essentially round or triangular cross-sectional area.

[0121] The composition can also be formulated such that it is fluid and “self-leveling” or only slightly thixotropic and can be poured out for application. As a coating, it can subsequently be distributed, for example, over an area down to the desired layer thickness, for example by means of a roller, a slide bar, a notched trowel or a palette knife. In one operation, typically a layer thickness in the range from 0.5 to 3 mm, especially 1 .0 to 2.5 mm, is applied.

[0122] The composition can also be used as a cast elastomer for different applications.

[0123] Furthermore, the composition according to the present invention may also be used as a drying agent.

[0124] Suitable substrates which can be bonded or sealed or coated with the composition are especially glass, glass ceramic, concrete, mortar, fiber cement, especially fiber cement boards, brick, tile, gypsum, especially gypsum boards, or natural stone such as granite or marble; repair or leveling compounds based on PCC (polymer-modified cement mortar) or ECC (epoxy resin- modified cement mortar); metals or alloys, such as aluminum, copper, iron, steel, nonferrous metals, including surface-finished metals, or alloys such as galvanized or chromed metals; asphalt or bitumen; leather, textiles, paper, wood, woodbase materials bonded with resins such as phenolic, melamine or epoxy resins, resin-textile composites or further polymer composites; plastics such as rigid and flexible PVC, polycarbonate, polystyrene, polyester, polyamide, PM MA, ABS, SAN, epoxy resins, phenolic resins, PUR, POM, thermoplastic elastomers (TPE, especially TPU), expanded thermoplastic elastomers, TPO, PE, PP, EPM or EPDM, in each case untreated or surface-treated, for example by means of plasma, corona or flames; fiber-re- inforced plastics, such as carbon fiber-reinforced plastics (CFP), glass fiber-reinforced plastics (GFP) and sheet molding compounds (SMC); insulation foams, especially made of EPS, XPS, PUR, PIR, rockwool, glass wool or foamed glass; coated or painted substrates, especially painted tiles, coated concrete, powder-coated metals or alloys or painted metal sheets; paints or varnishes, especially automotive topcoats.

[0125] If required, the substrates can be pretreated prior to application, especially by physical and / or chemical cleaning methods or the application of an activator or a primer. It is possible to bond and / or seal two identical or two different substrates.

[0126] The application and curing of the composition afford an article bonded or sealed or coated with the composition. This article may be a built structure or a part thereof, especially a built structure in civil engineering above or below ground, a bridge, a roof, a staircase or a facade, or it may be an industrial good or a consumer good, especially a window, a pipe, a rotor blade of a wind turbine, a domestic appliance or a mode of transport such as, in particular, an automobile, a bus, a truck, a rail vehicle, a ship, an aircraft or a helicopter, or an installable component thereof.

[0127] The composition of the invention has advantageous properties. It is particularly storage-stable with exclusion of moisture, even in the case of highly reactive aromatic isocyanate groups such as those of MDL It has a comparatively long open time which enables seamless leveling of the material applied or positioning or readjustment of the objects bonded therewith over a prolonged period after application, which is important, for example, in the case of coatings over a large area or long sealing strips, or in the case of bonding of large or complex objects. The curing proceeds rapidly, in a blister-free manner and without troublesome odor emissions, giving rise to a cured material having good strength, extensibility and elasticity which does not tend to have problems with plasticizer migration such as bleeding, substrate discoloration or stress-cracking in the substrate.

[0128] Compositions comprising the aldimines or oxazolidines according to the present invention as latent hardeners show very good adhesion and a rapid increase in viscosity, which results in very good initial strength in the adhesive bond. The compositions according to the invention also show good adhesion and strength in the cured adhesive bond, and very good hydrolysis resistance without formation of odorous side products or bubble formation.

[0129] Further embodiments of the present invention can be found in the claims and the examples. It will be appreciated that the features of the subject matter / processes / uses according to the invention that are mentioned above and elucidated below are usable not only in the combination specified in each case but also in other combinations without departing from the scope of the invention. For example, the combination of a preferred feature with a particularly preferred feature or of a feature not characterized further with a particularly preferred feature etc. is thus also encompassed implicitly even if this combination is not mentioned explicitly.

[0130] Illustrative embodiments of the present invention are listed below, but these do not restrict the present invention. In particular, the present invention also encompasses those embodiments which result from the dependency references and hence combinations specified hereinafter.

[0131] 1 . A latent hardener based on hydroxy methylfurfural which is obtainable by a process comprising the reaction of hydroxymethylfurfural or a derivative thereof and at least one amine A having at least one amino group.

[0132] 2. The latent hardener according to embodiment 1 , wherein the hardener is an aldimine or oxazolidine.

[0133] 3. The latent hardener according to embodiment 1 or 2, wherein the amine A has 1 to 4 amino groups, in particular 1 or 2 amino groups. 4. The latent hardener according to any one of embodiments 1 to 3, wherein the amine is an aliphatic amine.

[0134] 5. The latent hardener according to any one of embodiments 1 to 4, wherein the derivative of hydroxymethylfurfural is selected from the group consisting of ethers, esters and urethanes.

[0135] 6. The latent hardener according to any one of embodiments 1 to 5, wherein the latent hardener has the general formula (I): wherein A is selected from the group consisting of -O-, -O(CO)-, and -O(CO)NH- groups, R° is H or a linear or branched or cyclic alkylene chain or arylalkyl residue, preferably having 2 to 300 carbon atoms, more preferable alkyl or cycloalkyl or arylalkyl residue having 1 to 40 C atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen, and optionally one or more functional groups and

[0136] R is a linear or branched or cyclic alkylene chain, preferably having 2 to 300 carbon atoms, more preferable having 2 to 40 carbon atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen, or for a singly or multiply unsaturated linear or branched or cyclic hydrocarbon chain, preferably having 2 to 16 carbon atom, and n is 2, 3, 4, 5, or 6, preferably 2, 3 or 4, more preferably 2 or 3, in particular 2.

[0137] 7. The latent hardener according to any one of embodiments 1 to 6, wherein the latent hardener has the general formula (I*): wherein

[0138] A is selected from the group consisting of -O-, -O(CO)-, and -O(CO)NH- groups,

[0139] R° is H or a linear or branched or cyclic alkylene chain or arylalkyl residue, preferably having 2 to 300 carbon atoms, more preferable alkyl or cycloalkyl or arylalkyl residue having 1 to 40 C atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen and optionally one or more functional groups and

[0140] R is a linear or branched or cyclic alkylene chain, preferably having 2 to 300 carbon atoms, more preferable having 2 to 40 carbon atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen, or for a singly or multiply unsaturated linear or branched or cyclic hydrocarbon chain, preferably having 2 to 16 carbon atom. 8. The latent hardener according to any one of embodiments 1 to 5, wherein the latent hardener has the general formula (II): wherein A is selected from the group consisting of -O-, -O(CO)-, and -O(CO)NH- groups, R1is an alkyl or cycloalkyl or arylalkyl radical, preferably having 1 to 8 carbon atoms, and may have at least one ether oxygen and / or further functional groups such as for example one or more OH or NH2 groups and

[0141] R is a linear or branched or cyclic alkylene chain, preferably having 2 to 300 carbon atoms, more preferable having 2 to 40 carbon atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen, or for a singly or multiply unsaturated linear or branched or cyclic hydrocarbon chain preferably having 2 to 16 carbon atom, and n is 2, 3, 4, 5, or 6, preferably 2, 3 or 4, more preferably 2 or 3, in particular 2.

[0142] 9. The latent hardener according to any one of embodiments 1 to 5, wherein the latent hardener has the general formula (II): wherein A is selected from the group consisting of -O-, -O(CO)-, and -O(CO)NH- groups, R° is H or a linear or branched or cyclic alkylene chain or arylalkyl residue, preferably having 2 to 300 carbon atoms, more preferable alkyl or cycloalkyl or arylalkyl residue having 1 to 40 C atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen and optionally one or more functional groups and

[0143] R1is an alkyl or cycloalkyl or arylalkyl radical, preferably having 1 to 8 carbon atoms, and may have at least one ether oxygen and / or further functional groups such as for example one or more OH or NH2 groups

[0144] 10. The latent hardener according to any one of embodiments 1 to 9, wherein the derivative of hydroxymethylfurfural is selected from the group consisting of ethers, esters and urethanes having linear or branched C4-C36 alkyl chains, optionally having one or more OH or NH2 end groups.

[0145] 11. A process for the preparation of a latent hardener comprising step (i) (i) reacting hydroxymethylfurfural or a derivative thereof and at least one amine A having at least one amino group.

[0146] 12. The process according to embodiment 11 , wherein the process comprises steps (i’) and (ii’)

[0147] (i’) reacting hydroxymethylfurfural and at least one amine A having at least one amino group to obtain a hydroxym ethylfurfural derivative (HD1) with free OH groups,

[0148] (ii’) reacting the hydroxym ethylfurfural derivative (HD1) with a compound (C1) having functional groups reactive towards OH groups to obtain an aldimine.

[0149] 13. The process according to embodiment 11 , wherein step (i) comprises steps (i.1) and (i.2)

[0150] (1.1) reacting hydroxy methylfurfural with a compound (01) having functional groups reactive towards OH groups to obtain a hydroxymethylfurfural derivative (HD2) with a functionalized OH group,

[0151] (1.2) reacting the hydroxym ethylfurfural derivative (HD2) obtained in step (i.1) with at least one amine A having at least one amino group to obtain an aldimine.

[0152] 14. The process according to embodiment 11 , wherein step (i) comprises steps (i.a) and (i.b) (i.a) reacting hydroxy methylfurfural with a compound (C1) having functional groups reactive towards OH groups to obtain a hydroxymethylfurfural derivative (HD2) with a functionalized OH group,

[0153] (i.b) reacting the hydroxym ethylfurfural derivative (HD2) obtained in step (i.1) with at least one amine A having at least one amino group to obtain an oxazolidine.

[0154] 15. The process according to embodiment 11 , wherein step (i) comprises steps (i.X) and (i.Y): (i.X) reacting hydroxy methylfurfural with a compound (02) having at least two functional groups reactive towards OH groups to obtain a hydroxy methylfurfural derivative (HD3) with a functionalized OH group,

[0155] (i.Y) reacting the hydroxymethylfurfural derivative (HD3) obtained in step (i.X) with at least one amine A having at least one amino group to obtain an oxazolidine.

[0156] 16. A composition comprising

[0157] (a) at least one latent hardener according to any one of embodiments 1 to 10, and

[0158] (b) at least one monomer or prepolymer selected from the group consisting of an epoxy compound, an acrylate compound, an isocyanate compound, or an anhydride compound.

[0159] 17. A composition comprising

[0160] (a) at least one latent hardener based on hydroxymethylfurfural which is obtainable by a process comprising the reaction of hydroxymethylfurfural or a derivative thereof and at least one amine A having at least one amino group, and (b) at least one monomer or prepolymer selected from the group consisting of an epoxy compound, an acrylate compound, an isocyanate compound, or an anhydride compound.

[0161] 18. The composition according to embodiment 17, wherein the hardener is an aldimine or ox- azolidine.

[0162] 19. The composition according to embodiment 17 or 18, wherein the amine A has 1 to 4 amino groups, in particular 1 or 2 amino groups.

[0163] 20. The composition according to any one of embodiments 17 to 19, wherein the amine is an aliphatic amine.

[0164] 21 . The composition according to any one of embodiments 17 to 20, wherein the derivative of hydroxymethylfurfural is selected from the group consisting of ethers, esters and urethanes.

[0165] 22. The composition according to any one of embodiments 17 to 21 , wherein the latent hardener has the general formula (I): wherein A is selected from the group consisting of -O-, -O(CO)-, and -O(CO)NH- groups, R° is H or a linear or branched or cyclic alkylene chain or arylalkyl residue, preferably having 2 to 300 carbon atoms, more preferable alkyl or cycloalkyl or arylalkyl residue having 1 to 40 C atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen, and optionally one or more functional groups and

[0166] R is a linear or branched or cyclic alkylene chain, preferably having 2 to 300 carbon atoms, more preferable having 2 to 40 carbon atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen, or for a singly or multiply unsaturated linear or branched or cyclic hydrocarbon chain, preferably having 2 to 16 carbon atom, and n is 2, 3, 4, 5, or 6, preferably 2, 3 or 4, more preferably 2 or 3, in particular 2.

[0167] 23. The composition according to any one of embodiments 17 to 22, wherein the latent hardener has the general formula (I*): wherein

[0168] A is selected from the group consisting of -O-, -O(CO)-, and -O(CO)NH- groups,

[0169] R° is H or a linear or branched or cyclic alkylene chain or arylalkyl residue, preferably having 2 to 300 carbon atoms, more preferable alkyl or cycloalkyl or arylalkyl residue having 1 to 40 C atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen and optionally one or more functional groups and

[0170] R is a linear or branched or cyclic alkylene chain, preferably having 2 to 300 carbon atoms, more preferable having 2 to 40 carbon atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen, or for a singly or multiply unsaturated linear or branched or cyclic hydrocarbon chain, preferably having 2 to 16 carbon atom. The composition according to any one of embodiments 17 to 21 , wherein the latent hardener has the general formula (II): wherein A is selected from the group consisting of -O-, -O(CO)-, and -O(CO)NH- groups, R1is an alkyl or cycloalkyl or arylalkyl radical, preferably having 1 to 8 carbon atoms, and may have at least one ether oxygen and / or further functional groups such as for example one or more OH or NH2 groups and

[0171] R is a linear or branched or cyclic alkylene chain, preferably having 2 to 300 carbon atoms, more preferable having 2 to 40 carbon atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen, or for a singly or multiply unsaturated linear or branched or cyclic hydrocarbon chain preferably having 2 to 16 carbon atom, and n is 2, 3, 4, 5, or 6, preferably 2, 3 or 4, more preferably 2 or 3, in particular 2. The composition according to any one of embodiments 17 to 21 , wherein the latent hardener has the general formula (II): wherein A is selected from the group consisting of -O-, -O(CO)-, and -O(CO)NH- groups, R° is H or a linear or branched or cyclic alkylene chain or arylalkyl residue, preferably having 2 to 300 carbon atoms, more preferable alkyl or cycloalkyl or arylalkyl residue having 1 to 40 C atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen and optionally one or more functional groups and R1is an alkyl or cycloalkyl or arylalkyl radical, preferably having 1 to 8 carbon atoms, and may have at least one ether oxygen and / or further functional groups such as for example one or more OH or NH2 groups

[0172] 26. The composition according to any one of embodiments 16 to 25, wherein the composition comprises at least one polyurethane polymer containing isocyanate groups.

[0173] 27. The composition according to any one of embodiments 16 to 26, wherein the composition additionally comprises at least one further constituent selected from catalysts, fillers, plasticizers and solvents.

[0174] 28. The composition according to any one of embodiments 16 to 27, wherein the composition is an adhesive or a sealant or a composition for preparing a coating, an elastomer or a foam.

[0175] 29. A method comprising latently hardening compositions containing a prepolymer selected from the group consisting of an epoxy compound, an acrylate compound, an isocyanate compound, or an anhydride compound with at least one latent hardener according to any one of embodiments 1 to 10.

[0176] 30. A method comprising latently hardening compositions containing compounds with isocyanate groups or epoxy groups with at least one latent hardener according to any one of embodiments 1 to 10.

[0177] 31 . A method comprising latently hardening compositions containing compounds with isocyanate groups or epoxy groups with at least one latent hardener based on hydroxymethylfurfural which is obtainable by a process comprising the reaction of hydroxym ethylfurfural or a derivative thereof and at least one amine A having at least one amino group.

[0178] 32. The method according to embodiment 31 , wherein the hardener is an aldimine or oxazoli- dine.

[0179] 33. The method according to embodiment 31 or 32, wherein the amine A has 1 to 4 amino groups, in particular 1 or 2 amino groups.

[0180] 34. The method according to any one of embodiments 31 to 33, wherein the amine is an aliphatic amine.

[0181] 35. The method according to any one of embodiments 31 to 34, wherein the derivative of hydroxymethylfurfural is selected from the group consisting of ethers, esters and urethanes.

[0182] 36. The method according to any one of embodiments 31 to 35, wherein the latent hardener has the general formula (I): wherein A is selected from the group consisting of -O-, -O(CO)-, and -O(CO)NH- groups, R° is H or a linear or branched or cyclic alkylene chain or arylalkyl residue, preferably having 2 to 300 carbon atoms, more preferable alkyl or cycloalkyl or arylalkyl residue having 1 to 40 C atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen, and optionally one or more functional groups and

[0183] R is a linear or branched or cyclic alkylene chain, preferably having 2 to 300 carbon atoms, more preferable having 2 to 40 carbon atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen, or for a singly or multiply unsaturated linear or branched or cyclic hydrocarbon chain, preferably having 2 to 16 carbon atom, and n is 2, 3, 4, 5, or 6, preferably 2, 3 or 4, more preferably 2 or 3, in particular 2.

[0184] 37. The method according to any one of embodiments 31 to 36, wherein the latent hardener has the general formula (I*): wherein

[0185] A is selected from the group consisting of -O-, -O(CO)-, and -O(CO)NH- groups,

[0186] R° is H or a linear or branched or cyclic alkylene chain or arylalkyl residue, preferably having 2 to 300 carbon atoms, more preferable alkyl or cycloalkyl or arylalkyl residue having 1 to 40 C atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen and optionally one or more functional groups and

[0187] R is a linear or branched or cyclic alkylene chain, preferably having 2 to 300 carbon atoms, more preferable having 2 to 40 carbon atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen, or for a singly or multiply unsaturated linear or branched or cyclic hydrocarbon chain, preferably having 2 to 16 carbon atom.

[0188] 38. The method according to any one of embodiments 31 to 35, wherein the latent hardener has the general formula (II): wherein A is selected from the group consisting of -O-, -O(CO)-, and -O(CO)NH- groups, R1is an alkyl or cycloalkyl or arylalkyl radical, preferably having 1 to 8 carbon atoms, and may have at least one ether oxygen and / or further functional groups such as for example one or more OH or NH2 groups and

[0189] R is a linear or branched or cyclic alkylene chain, preferably having 2 to 300 carbon atoms, more preferable having 2 to 40 carbon atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen, or for a singly or multiply unsaturated linear or branched or cyclic hydrocarbon chain preferably having 2 to 16 carbon atom, and n is 2, 3, 4, 5, or 6, preferably 2, 3 or 4, more preferably 2 or 3, in particular 2.

[0190] 39. The method according to any one of embodiments 31 to 35, wherein the latent hardener has the general formula (II): wherein A is selected from the group consisting of -O-, -O(CO)-, and -O(CO)NH- groups, R° is H or a linear or branched or cyclic alkylene chain or arylalkyl residue, preferably having 2 to 300 carbon atoms, more preferable alkyl or cycloalkyl or arylalkyl residue having 1 to 40 C atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen and optionally one or more functional groups and

[0191] R1is an alkyl or cycloalkyl or arylalkyl radical, preferably having 1 to 8 carbon atoms, and may have at least one ether oxygen and / or further functional groups such as for example one or more OH or NH2 groups

[0192] 40. The use of a latent hardener according to any one of embodiments 1 to 10 in a composition which comprises components that are reactive toward amines.

[0193] 41 . The use of latent hardener according to embodiment 40, characterized in that the components that are reactive toward amines are isocyanates.

[0194] 42. The use of a latent hardener according to embodiment 40 or 41 , characterized in that the composition is used as an adhesive, sealant, foam, coating or covering.

[0195] The present invention can be further explained and illustrated on the basis of the following examples. However, it will be understood that these examples are included merely for purposes of illustration and are not intended to limit the scope of the invention in any way. Examples

[0196] I. Materials used

[0197] 5-hydroxymethylfurfural (HMF, 98%) was procured from Manchester Organics and utilized without further purification.

[0198] Lauroyl chloride (98%), lauric acid(>98%), 1 -dodecanol (>98%), n-hexylisocyanate (97%), Dibutyltin dilaurate (DBTL, 95%), p-tolylisocyanate (99%), 1 ,4-Diazabicyclo[2.2.2]octane (DABCO, >99%) diisodecyl phthalate, Jeffamine D230 (Mn~230), Jeffamine T403 (Mn~440), isophorone diamine (IPDA, >99%), 1 ,5-Diamino-2-methylpentane (99%), 2-ethylhexyla- mine (98%), diethanolamine (>98%), N-methylethanolamine (>98%), benzoic acid (> 99.5%), bisphenol A diglycidyl ether (DGEBA) and 3-hydroxy-2,2-di methyl propanal were sourced from Merck and used without purification.

[0199] N,N'-Dicyclohexylcarbodiimide (DCC, >98%), 4-Dimethylaminopyridine (DMAP, >99%), n- dodecylisocyanate (>98%), and 2-ethylhexanoyl chloride (>98%) were obtained from TCI Europe and used as received.

[0200] Ethyl acetate, chloroform, dichloromethane, tetra hydrofuran, and pyridine were procured from Biosolve B.V. and used without further purification.

[0201] Vestamin A139 was supplied by Evonik. Zeolite , hydrogen was purchased from Thermo Scientific.

[0202] Methylene diphenyl diisocyanate (MDI, Lupranat ME), Lupranol 1005 / 1 (polypropylene glycol with an average molecular weight of 4000 and OH number of 28 mg KOH / g) and Lupranol 2095 (trifunctional high reactive polyether polyol which contains primary hydroxyl groups and with OH number of 35 mg KOH / g) were obtained from BASF (Germany) and used as received.

[0203] The amine functionalities of Jeffamine D230 and Jeffamine T403 were determined to be 1.4 and 2.2 through titrimetric1H NMR analysis.

[0204] II. Methods

[0205] The1H NMR spectra were recorded on Bruker UltraShield (400 MHz) using CD2CI2, CDCI3 or DMSO-de as the solvents. The experimental free isocyanate content of the prepolymer was determined by using a Metrohm 916 Ti-Touch titrator according to the ASTM D5155- 19 standard method.

[0206] The synthesized isocyanate prepolymers were poured into PTFE molds and cured at 23 °C and 65% relative humidity for 1 week. The skin-forming time of these films, with a thickness of approximately 1.5 mm, was determined by the duration until the applied layer no longer left any residues on a piece of paper.

[0207] Mechanical characterizations (tensile tests) were performed on Zwick / Roell Intelligent testing with 200 N load cell using dumbbell-shaped specimens (effective length: 12 mm, width: 2 mm, and measured thickness around 1.5 mm) with a strain rate of 50 mm / min after 1 week of curing at 23 °C and 65% relative humidity.

[0208] Bubble formation was assessed qualitatively on the basis of the quantity of bubbles which occurred in the course of curing (at 23 °C and 65% relative humidity) of the films.

[0209] The odor was assessed on the cast films by smelling with the nose at a distance of 10 cm, first on the composition applied immediately beforehand and a second time 7 days thereafter on the composition cured at 23 °C and 65% relative humidity.

[0210] III. Synthesis

[0211] 1. Synthesis of aldehydes

[0212] 1.1 Aldehyde A1

[0213] 5-hydroxymethylfurfural (HMF, 50.0 g, 396.5 mmol) was dissolved in chloroform (300 ml) and pyridine (40 ml) under argon in a three-neck round-bottom flask. After purging with argon for 30 min, lauroyl chloride (86.7 g, 396.5 mmol) was added, and the mixture was allowed to mix for 24 hours at room temperature. After completion of the reaction, the product was extracted twice with 1 M HCI (100 ml) and once with de-ionized water (100 ml). Organic layer was dried over magnesium sulphate (MgSC ) and then filtered. Finally, the aldehyde A1 was obtained as a white powder with melting point of 55 °C after evaporation of chloroform using rotary evaporator.1H NMR (400 MHz, CDCh) 5 9.64 (s, 1 H), 7.21 (d, J = 3.6 Hz, 1 H), 6.58 (d, J = 3.6 Hz, 1 H), 5.13 (s, 2H), 2.35 (t, J = 7.5 Hz, 2H), 1.63 (p, J = 7.1 Hz, 2H), 1.26 (m, 16H), 0.88 (t, J = 6.8 Hz, 3H).

[0214] 1.2 Aldehyde A1

[0215] 5-hydroxymethylfurfural (HMF, 2.5 g, 20.0 mmol), lauric acid (2.0 g, 10.0 mmol), 4-Dime- thylaminopyridine (DMAP, 110 mg) was dissolved in anhydrous dichloromethane (20 ml) under argon in a three-neck round-bottom flask. After purging with argon for 30 min, the reaction temperature was lowered to 0°C. N,N'-Dicyclohexylcarbodiimide (DCC, 2.3 g, 11.0 mmol) was added at this temperature and the mixture was allowed to mix for 5 minutes at 0 °C. Later on, the temperature was raised to room temperature and the mixture was allowed to mix for 3 hours at room temperature. The precipitated dicyclohexylurea (DCU) and excess HMF was removed by passing the dichloromethane solution from silica plug. Finally, the aldehyde A1 was obtained as a white powder after evaporation of dichloromethane using rotary evaporator.1H NMR (400 MHz, CDCI3) 5 9.64 (s, 1 H), 7.21 (d, J = 3.5 Hz, 1 H), 6.58 (d, J = 3.5 Hz, 1 H), 5.13 (s, 2H), 2.35 (t, J = 7.5 Hz, 2H), 1.64 (p, J = 7.1 Hz, 2H), 1.26 (m, 16H), 0.88 (t, J = 6.8 Hz, 3H). Aldehyde A2

[0216] 5-hydroxymethylfurfural (HMF, 10.0 g, 79.3 mmol) was dissolved in chloroform (300 ml) and pyridine (10 ml) under argon in a three-neck round-bottom flask. After purging with argon for 30 min, 2-ethylhexanoyl chloride (12.9 g, 79.3 mmol) was added, and the mixture was allowed to mix for 24 hours at room temperature. After completion of the reaction, the product was extracted twice with 1 M HCI (100 ml) and once with de-ionized water (100 ml). Organic layer was dried over magnesium sulphate (MgSO i) and then filtered. Finally, the aldehyde A2 was obtained as a yellow liquid, which could be used as a plasticizer for the reference iso-prepolymers. ,1H NMR (400 MHz, CDCh) 5 9.63 (s, 1 H), 7.20 (d, J = 3.5 Hz, 1 H), 6.57 (d, J = 3.6 Hz, 1 H), 5.14 (s, 2H), 2.32 (m, 1 H), 1.69 - 1.39 (m, 4H), 1.35 - 1.12 (m, 4H), 0.85 (m, 6H). Aldehyde A3

[0217] Beta-H-zeolites (5.1 g) were placed in a Schlenk flask and activated upon heating to 2000C for 2 hours under vacuum. After reducing the temperature to 100 °C, 1 -dodecanol (18.6 g, 100 mmol) and 5-hydroxymethylfurfural (HMF, 12.6 g, 100 mmol) were added to the mixture and the mixture was allowed to mix at this temperature under vacuum for 12 hours. Finally, the product was filtrated through a silica plug using ethyl acetate (EA) and the Aldehyde A3 was obtained as a yellow powder after evaporation of EA using rotary evaporator.1H NMR (400 MHz, CDCh) 5 9.62 (s, 1 H), 7.21 (d, J = 3.5 Hz, 1 H), 6.52 (d, J = 3.5 Hz, 1 H), 4.53 (s, 2H), 3.51 (t, J = 6.7 Hz, 2H), 1.64 - 1.57 (m, 2H), 1.27 (m, 18H), 0.88 (t, J = 6.8 Hz, 3H). Aldehyde A4

[0218] 5-hydroxymethylfurfural (HMF, 4.96 g, 39.3 mmol), n-hexylisocyanate (5.00 g, 39.3 mmol) were dissolved in 25 ml TH F in a 50 ml round bottom flask. Following that, Dibutyltin dilaurate catalyst (DBTL, 621 mg, 0.98 mmol) was added under argon. The mixture was allowed to mix at room temperature under argon for 12 hours. Finally, the product was filtrated through a silica plug using ethyl acetate (EA). After removal of EA using rotary evaporator, the solid mixture was recrystallized from cold isopropanol. The aldehyde A4 was obtained as a yellow powder after drying the crystals in a vacuum oven at 40 °C overnight.1H NMR (400 MHz, CDCh) 6 7.20 (d, J = 3.6 Hz, 1 H), 6.58 (d, J = 3.6 Hz, 1 H), 5.11 (s, 2H), 4.75 (s, 1 H), 3.18 (q, J = 6.7 Hz, 2H), 1.52 - 1.44 (m, 2H), 1.29 (s, 6H), 0.92 - 0.84 (m, 3H). Aldehyde A5 5-hydroxymethylfurfural (HMF, 3.00 g, 23.8 mmol), n-dodecylisocyanate (5.03 g, 23.8 mmol) were dissolved in 25 ml TH F in a 50 ml round bottom flask. Following that, Dibutyltin dilaurate catalyst (DBTL, 376 mg, 0.59 mmol) was added under argon. The mixture was allowed to mix at room temperature under argon for 12 hours. Finally, the product was filtrated through a silica plug using ethyl acetate (EA). After removal of EA using rotary evaporator, the solid mixture was recrystallized from cold isopropanol. The aldehyde A5 was obtained as a yellow powder after drying the crystals in a vacuum oven at 40 °C overnight. 1H NMR (400 MHz, CDCI3) 5 9.63 (s, 1 H), 7.20 (d, J = 3.5 Hz, 1 H), 6.58 (d, J = 3.5 Hz, 1 H), 5.11 (s, 2H), 4.76 (s, 1 H), 3.18 (q, J = 6.7 Hz, 2H), 1.48 (q, J = 7.1 Hz, 2H), 1.27 (d, J = 9.1 Hz, 18H), 0.88 (t, J = 6.8 Hz, 3H).

[0219] 1.7 Aldehyde A5

[0220] 5-hydroxymethylfurfural (HMF, 3.00 g, 23.8 mmol), n-dodecylisocyanate (5.03 g, 23.8 mmol) were mixed at room temperature in a 50 ml round bottom flask and heated to 50 °C until a homogeneous mixture was obtained. Following that, Dibutyltin dilaurate catalyst (DBTL, 50 mg, 0.079 mmol) was added. The mixture was allowed to stir at this temperature under argon for 10 minutes. Finally, the resulting product aldehyde A5 was obtained as a yellow powder.1H NMR (400 MHz, CDCI3) 5 9.63 (s, 1 H), 7.20 (d, J = 3.5 Hz, 1 H), 6.58 (d, J = 3.6 Hz, 1 H), 5.11 (s, 2H), 4.75 (s, 1 H), 3.18 (q, J = 6.7 Hz, 2H), 1.48 (q, J = 7.1 Hz, 2H), 1 .35 - 1 .14 (m, 18H), 0.88 (t, J = 6.7 Hz, 3H).

[0221] 1.8 Aldehyde A6

[0222] 5-hydroxymethylfurfural (HMF, 5.00 g, 39.6 mmol), p-tolyl isocyanate (5.00 g, 39.6 mmol) were dissolved in 25 ml TH F in a 50 ml round bottom flask. Following that, Dibutyltin dilaurate catalyst (DBTL, 626 mg, 0.99 mmol) was added under argon. The mixture was allowed to mix at room temperature under argon for 12 hours. Finally, the product was filtrated through a silica plug using ethyl acetate (EA). After removal of EA using rotary evaporator, the solid mixture was recrystallized from isopropanol. The aldehyde A6 was obtained as a yellow powder after drying the crystals in a vacuum oven at 40 °C overnight.1H NMR (400 MHz, CDCI3) 5 9.64 (s, 1 H), 7.24 (m, 2H), 7.21 (d, J= 3.6 Hz, 1 H), 7.11 (d, J= 8.1 Hz, 2H), 6.67 (s, 1 H), 6.63 (d, J= 3.6 Hz, 1 H), 5.21 (s, 2H), 2.30 (s, 3H).

[0223] 2. Synthesis of Aldimines:

[0224] The amine functionalities of Jeffamine D230 and Jeffamine T403 were determined to be 1.4 and 2.2 through titrimetric1H NMR analysis. These values were used to calculate the amount reactants in following reactions.

[0225] 2.1 Aldimine ALDI Aldehyde A1 (2.0 g, 6.5 mmol) was mixed with Jeffamine D230 (0.88 g). The mixture was rotavapped at 60°C at 15 mbar for 2 hours. The obtained liquid was further dried at 40 °C in vacuum oven overnight. Finally, Aldimine ALD1 was obtained as a light-brown liquid.1H NMR (400 MHz, CDCI3) 58.14 - 7.99 (m, 2H), 6.69 (m, 2H), 6.46 (m, 2H), 5.08 (s, 4H), 3.99 - 2.87 (m, 13H), 2.32 (t, J = 7.6 Hz, 4H), 1.61 (p, J = 7.3 Hz, 4H), 1.34 - 0.99 (m, 45H), 0.88 (t, J = 6.7 Hz, 6H).

[0226] 2.2 Aldimine ALD2

[0227] Aldehyde A3 (5.46 g, 0.019 mol) was mixed with Jeffamine D230 (2.51 g). The mixture was rotavapped at 60°C at 15 mbar for 2 hours. The obtained liquid was further dried at 40 °C in vacuum oven overnight. Finally, Aldimine ALD2 was obtained as a honey-colored liquid. 1H NMR (400 MHz, CDCI3) 5 8.18 - 7.95 (m, 2H), 6.69 (m, 2H), 6.38 (m, 2H), 4.48 (s, 4H), 3.72 - 2.94 (m, 17H), 1.58 (m, 4H), 1.39 - 0.95 (m, 49H), 0.88 (t, J = 6.8 Hz, 6H).

[0228] 2.3 Aldimine ALD3

[0229] Aldehyde A5 (3.40 g, 10.1 mmol) was mixed with Jeffamine D230 (1.36 g). The mixture was rotavapped at 60°C at 15 mbar for 2 hours. The obtained liquid was further dried at 40 °C in vacuum oven overnight. Finally, Aldimine ALD3 was obtained as a honey-colored viscous liquid.1H NMR (400 MHz, CDCI3) 5 8.10 - 7.98 (m, 2H), 6.67 (m, 2H), 6.45 (m, 2H), 5.06 (s, 4H), 4.80 (s, 2H), 3.67 - 3.24 (m, 13H), 3.15 (m, 4H), 1.51 - 1.43 (m, 4H), 1.34 - 0.96 (m, 49H), 0.87 (t, J = 6.8 Hz, 6H).

[0230] 2.4 Aldimine ALD3

[0231] 5-hydroxymethylfurfural (HMF, 3.00 g, 23.8 mmol), n-dodecylisocyanate (5.03 g, 23.8 mmol) were mixed at room temperature in a 50 ml round bottom flask and heated to 50 °C until a homogeneous mixture was obtained. Following that, DBTL (50 mg, 0.079 mmol) was added. The mixture was allowed to stir at this temperature under argon for 10 minutes. After the reaction of isocyanate and HMF was completed, Jeffamine D230 (3.90 g) was introduced and the reaction mixture was thoroughly homogenized and subjected to rotary evaporation for 3 hours at 15 mbar and a temperature of 60°C. Aldimine ALD3 was obtained as a honey-colored viscous liquid.1H NMR (400 MHz, CDCI3) 5 8.10 - 7.98 (m, 2H), 6.67 (m, 2H), 6.45 (m, 2H), 5.06 (s, 4H), 4.80 (s, 2H), 3.67 - 3.24 (m, 13H), 3.15 (m, 4H), 1.51 - 1 .43 (m, 4H), 1 .34 - 0.96 (m, 49H), 0.87 (t, J = 6.8 Hz, 6H).

[0232] 2.5 Aldimine ALD4

[0233] Aldehyde A4 (2.0 g, 7.9 mmol) was mixed with Jeffamine D230 (1 .07 g). The mixture was rotavapped at 60°C at 15 mbar for 2 hours. The obtained liquid was further dried at 40 °C in vacuum oven overnight. Finally, Aldimine ALD4 was obtained as a honey-colored viscous liquid.1H NMR (400 MHz, CDCI3) 5 8.31 - 7.83 (m, 2H), 6.68 (m, 2H), 6.46 (m, 2H), 5.06 (m, 4H), 4.82 (s, 2H), 3.77 - 3.28 (m, 13H), 3.16 (m, 4H), 1.47 (m, 4H), 1.36 - 0.98 (m, 25H), 0.92 - 0.83 (m, 6H).

[0234] 2.6 Aldimine ALD5

[0235] Aldehyde A6 (5.22 g, 0.020 mmol) was mixed with Jeffamine D230 (2.72 g). The mixture was rotavapped at 60°C at 15 mbar for 2 hours. The obtained liquid was further dried at 40 °C in vacuum oven overnight. Finally, Aldimine ALD5 was obtained as a honey-colored viscous liquid.1H NMR (400 MHz, CDCI3) 5 8.18 - 7.95 (m, 2H), 7.26 (m, 4H), 7.14 - 6.99 (m, 4H), 6.67 (m, 2H), 6.46 (m, 2H), 5.18 - 4.79 (m, 4H), 3.67 - 3.04 (m, 13H), 2.34 - 2.18 (m, 6H), 1.29 - 0.85 (m, 13H).

[0236] 2.7 Aldimine ALD5

[0237] 5-hydroxymethylfurfural (HMF, 2.00 grams, 15.9 mmol) was mixed with Jeffamine D230 (2.15 g). The mixture was rotavapped at 60°C at 15 mbar for 2 hours. Further, p-tolylisocy- anate (2.11 grams, 15.9 mmol) was added to the mixture. Finally, the mixture was stirred at 60 °C under argon for 6 hours to yield ALD5 as a dark brown viscous liquid.1H NMR (400 MHz, CDCI3) 5 8.23 - 7.91 (m, 2H), 7.26 (m, 4H), 7.07 (m, 4H), 6.76 - 6.53 (m, 2H), 6.55 - 6.24 (m, 2H), 5.33 - 4.49 (m, 4H), 3.89 - 3.13 (m, 13H), 2.38 - 2.11 (m, 6H), 1.38 - 0.77 (m, 13H).

[0238] 2.8 Aldimine ALD6

[0239] Aldehyde A1 (2.0 g, 6.5 mmol) was mixed with Jeffamine T403 (1 .30 g). The mixture was rotavapped at 60 °C at 15 mbar for 2 hours. The obtained liquid was further dried at 40 °C in vacuum oven overnight. Finally, Aldimine ALD6 was obtained as a light brown-liquid.1H NMR (400 MHz, CDCI3) 58.15 - 7.92 (m, 3H), 6.69 (m, 3H), 6.46 (m, 3H), 5.08 (s, 6H), 3.97 - 2.82 (m, 31 H), 2.31 (m, 6H), 1 .61 (p, J = 7.4, 7.0 Hz, 6H), 1 .47 - 0.71 (m, 79H).

[0240] 2.8 Aldimine ALD7

[0241] Aldehyde A1 (2.0 g, 6.5 mmol) was mixed with isophorone diamine (0.55 g, 3.24 mmol). The mixture was rotavapped at 60°C at 15 mbar for 2 hours. The obtained liquid was further dried at 40 °C in vacuum oven overnight. Finally, Aldimine ALD7 was obtained as a brownliquid.1H NMR (400 MHz, CDCI3) 5 8.21 - 7.84 (m, 2H), 6.76 - 6.60 (m, 2H), 6.46 (m, 2H), 5.08 (m, 4H), 3.79 - 3.19 (m, 3H), 2.32 (m, 4H), 1.73 (s, 3H), 1.61 (m, 4H), 1.48 (m, 3H), 1.26 (m, 32H), 1.19 (s, 2H), 1.10 (s, 3H), 0.97 (m, 4H), 0.88 (t, J = 6.8 Hz, 6H).

[0242] 2.10 Aldimine ALD8

[0243] Aldehyde A1 (4.89 g, 15.9 mmol) was mixed with 1 ,5-Diamino-2-methylpentane (0.92 g, 7.9 mmol). The mixture was rotavapped at 60°C at 15 mbar for 2 hours. The obtained liquid was further dried at 40 °C in vacuum oven overnight. Finally, Aldimine ALD8 was obtained as a yellowish powder with a melting point of 45 °C.1H NMR (400 MHz, CDCh) 5 8.03 (d, J = 13.6 Hz, 2H), 6.68 (t, J = 3.7 Hz, 2H), 6.47 (d, J = 3.4 Hz, 2H), 5.08 (s, 4H), 3.57 (tq, J = 11 .6, 7.0, 6.1 Hz, 3H), 3.32 (dd, J = 11 .5, 7.3 Hz, 1 H), 2.32 (t, J = 7.5 Hz, 4H), 1 .97 (dt, J = 13.5, 7.5 Hz, 1 H), 1.78 (m, 2H), 1.61 (p, J = 7.0 Hz, 4H), 1.53 - 1.39 (m, 1 H), 1.26 (m, 34H), 0.93 (d, J = 6.6 Hz, 3H), 0.88 (t, J = 6.7 Hz, 6H).

[0244] 2.11 Aldimine ALD9

[0245] 5-hydroxymethylfurfural (HMF, 2.0 g, 15.9 mmol) was mixed with Jeffamine D230 (2.15 g). The mixture was rotavapped at 60°C at 15 mbar for 2 hours. The obtained liquid was further dried at 40 °C in vacuum oven overnight. Finally, Aldimine ALD9 was obtained as a darkbrown viscous liquid.1H NMR (400 MHz, CDCI3)5 8.25 - 7.67 (m, 2H), 6.85 - 6.57 (m, 2H),

[0246] 6.36 (m, 2H), 4.79 - 4.45 (m, 4H), 3.84 - 2.97 (m, 13H), 1.34 - 0.86 (m, 13H).

[0247] 2.12 Aldimine ALD10

[0248] 5-hydroxymethylfurfural (HMF, 2.0 g, 15.9 mmol) was mixed with 1 ,5-Diamino-2-methylpen- tane ( 0.92 g, 7.9 mmol). The mixture was rotavapped at 60°C at 0 bar for 2 hours. The obtained liquid was further dried at 40 °C in vacuum oven overnight. Finally, Aldimine ALD10 was obtained as a dark-brown viscous liquid.1H NMR (400 MHz, DMSO-de) 5 8.08 (d, J = 8.3 Hz, 2H), 6.80 (t, J = 3.4 Hz, 2H), 6.40 (d, J = 3.7 Hz, 2H), 5.36 (s, 2H), 4.43 (s, 4H), 3.47 (dtd, J = 13.1 , 7.0, 6.3, 3.3 Hz, 3H), 3.36 - 3.25 (m, 1 H), 1.83 - 1 .70 (m, 1 H), 1 .69 - 1.53 (m, 2H), 1.41 (ddd, J = 13.3, 10.8, 5.5 Hz, 1 H), 1.15 (dddd, J = 13.3, 10.3, 8.0, 5.4 Hz, 1 H), 0.88 (d, J = 6.7 Hz, 3H).

[0249] 2.13 Aldimine ALD11

[0250] 5-hydroxymethylfurfural (HMF, 0.82 g, 6.5 mmol) was mixed with Jeffamine T403 (1 .30 g). The mixture was rotavapped at 60°C at 15 mbar for 2 hours. The obtained liquid was further dried at 40 °C in vacuum oven overnight. Finally, Aldimine ALD11 was obtained as a brown, viscous-liquid.1H NMR (400 MHz, DMSO-ofe) 5 8.05 (m, 3H), 6.79 (m, 3H), 6.39 (m, 3H),

[0251] 5.37 (s, 3H), 4.43 (s, 6H), 3.64 - 3.01 (m, 31 H), 1 .37 - 0.60 (m, 31 H).

[0252] 2.14 Aldimine ALD12:

[0253] 5-hydroxymethylfurfural (HMF, 3.0 g, 23.8 mmol) was mixed with 2-ethylhexylamine (3.1 g, 23.8 mmol). The mixture was rotavapped at 60°C at 15 mbar for 2 hours. The obtained liquid was further dried at 40 °C in vacuum oven overnight.1H NMR (400 MHz, - CD2CI2) 5 8.00 (s, 1 H), 6.66 (d, J = 3.3 Hz, 1 H), 6.35 (d, J = 3.3 Hz, 1 H), 4.61 (s, 2H), 3.52 - 3.38 (m, 2H), 1.70 - 1 .58 (m, 1 H), 1 .44 - 1 .21 (m, 8H), 0.89 (t, J = 7.4 Hz, 6H).

[0254] 2.15 ALDR1 Benzaldehyde (2.0 g, 18.8 mmol) was mixed with Jeffamine D230 (2.55 g). The mixture was rotavapped at 60°C at 15 mbar for 2 hours. The obtained liquid was further dried at 40 °C in vacuum oven overnight. Finally, ALDR1 was obtained as a yellow-colored liquid.1H NMR (400 MHz, CDCI3) 5 8.36 - 8.19 (m, 1 H), 7.79 - 7.67 (m, 2H), 7.39 (dq, J = 5.3, 2.3 Hz, 3H), 3.73 - 2.98 (m, 7H), 1 .34 - 0.90 (m, 5H).

[0255] 2.16 Aldimine ALDR2

[0256] The structure of ALDR2 corresponds to the structure obtained from the example Polyal- dimine PA1 of US 2008 / 0114146 A1. This structure ALDR2 was prepared according to the following modified procedure: 3-hydroxy-2,2-di methyl propanal (0.72 g, 7.1 mmoles) was mixed with Jeffamine D230 (0.95 g). The mixture was rotavapped at 60 °C at 15 mbar for 2 hours. The liquid obtained was subsequently subjected to a reaction with lauroyl chloride (0.78 g, 3.6 mmoles) in a mixture chloroform and pyridine, at room temperature for 12 h. After evaporation of the solvents, the obtained liquid was dried at 40 °C in vacuum oven overnight.1H NMR (400 MHz, CDCI3) 5 7.55 (s, 2H), 4.16 - 3.85 (m, 4H), 3.61 - 3.05 (m, 13H), 2.29 (t, J= 7.5 Hz, 4H), 1.61 (p, 7.3 Hz, 4H), 1.27 (m, 32H), 1.16 - 0.99 (m, 25H),

[0257] 0.88 (t, J= 6.7 Hz, 6H).

[0258] 2.17 Aldimine ALDR3: Vestamin A139 (commercially available from Evonik).

[0259] 3. Synthesis of Oxazolidines:

[0260] 3.1 Oxazolidine Ox-R

[0261] Reference oxazolidine was prepared according to example Oxazolidine B-1 from US 11 ,535,694 B2. 63.09 g of diethanolamine was weighed in a round-bottom flask. To this flask, 64.95 g of benzaldehyde and 0.50 g of salicylic acid were added. Subsequently, the reaction mixture was thoroughly mixed at a temperature of 80 °C while maintaining a vacuum to remove formed water for 24 h. Furthermore, the mixture was purified by vacuum distillation, resulting in the formation of a clear liquid.1H NMR (400 MHz, CDCI3) 5 7.50 - 7.42 (m, 2H), 7.41 - 7.30 (m, 3H), 5.01 (s, 1 H), 4.14 - 3.99 (m, 2H), 3.64 (m, 1 H), 3.58 - 3.49 (m, 1 H), 3.37 (m, 1 H), 2.85 (s, 1 H), 2.84 - 2.71 (m, 2H), 2.57 (m, 1 H).

[0262] 3.2 Oxazolidine Ox-1

[0263] Diethanolamine (2.39 grams, 22.7 mmol) and 5-hydroxymethylfurfural (2.86 grams, 22.7 mmol) were placed in a 50 ml round bottom flask and mixed until homogeneity at 60 °C. The mixture was rotavapped at 60 °C at 15 mbar for 2 hours. The obtained liquid was further dried at 40 °C in vacuum oven overnight. Finally, Ox-1 was obtained as a brown-liquid.1H NMR (400 MHz, Chloroform-d) 5 6.35 (d, J = 3.2 Hz, 1 H), 6.23 (d, J = 3.2 Hz, 1 H), 5.12 (s, 1 H), 4.56 (s, 2H), 4.11 - 3.95 (m, 2H), 3.70 - 3.51 (m, 2H), 3.37 (ddd, J = 9.7, 6.8, 4.7 Hz, 1 H), 2.93 - 2.57 (m, 5H).

[0264] 3.3 Oxazolidine Ox-2

[0265] N-methylethanolamine (1 .28 g, 17.0 mmol) and aldehyde A1 (5.00 grams, 17.0 mmol) were placed in a 50 ml round bottom flask and mixed until homogeneity at 60 °C. The mixture was rotavapped at 60 °C at 15 mbar for 2 hours. The obtained liquid was further dried at 40 °C in vacuum oven overnight. Finally, Ox-2 was obtained as a yellow-liquid.1H NMR (400 MHz, Chloroform-o) 5 6.41 - 6.32 (m, 2H), 5.04 (s, 2H), 4.89 (s, 1 H), 4.11 - 3.96 (m, 2H), 3.33 (ddd, 10.3, 6.6, 4.2 Hz, 1 H), 2.74 (m, 1 H), 2.42 (s, 3H), 2.31 (t, 7.6 Hz, 2H),

[0266] 1.60 (m, 2H), 1.26 (m, 16H), 0.98 - 0.73 (m, 3H).

[0267] 3.4 Oxazolidine Ox-3

[0268] Diethanolamine (2.39 grams, 22.7 mmol) and aldehyde A1 (6.69 grams, 22.7 mmol) were placed in a 50 ml round bottom flask and mixed until homogeneity at 60 °C. The mixture was rotavapped at 60 °C at 15 mbar for 2 hours. The obtained liquid was further dried at 40 °C in vacuum oven overnight. Finally, Ox-3 was obtained as a yellow-liquid.1H NMR (400 MHz, Chloroform-d) 5 6.35 (q, J = 3.3 Hz, 2H), 5.18 (s, 1 H), 5.03 (s, 2H), 4.11 - 3.96 (m, 2H), 3.68 - 3.56 (m, 2H), 3.37 (ddd, J = 9.8, 6.9, 5.1 Hz, 1 H), 2.91 - 2.79 (m, 2H), 2.70 (m, 1 H), 2.52 - 2.45 (s, 1 H), 2.32 (t, J = 7.6 Hz, 2H), 1.61 (p, J = 7.3 Hz, 2H), 1.26 (t, 16H), 0.92 - 0.84 (m, 3H).

[0269] 3.5 Oxazolidine Ox-4

[0270] Diethanolamine (2.39 grams, 22.7 mmol) and aldehyde A4 (7.74 grams, 22.7 mmol) were placed in a 50 ml round bottom flask and mixed until homogeneity at 60 °C. The mixture was rotavapped at 60 °C at 15 mbar for 2 hours. The obtained liquid was further dried at 40 °C in vacuum oven overnight. Finally, Ox-4 was obtained as a yellow-liquid.1H NMR (400 MHz, CDCI3) 5 6.35 (m, 2H), 5.15 (s, 1 H), 5.00 (s, 2H), 4.78 (s, 1 H), 4.11 - 3.95 (m, 2H), 3.69 - 3.51 (m, 2H), 3.37 (m, 1 H), 3.16 (q, J = 6.7 Hz, 2H), 2.85 - 2.77 (m, 2H), 2.69 (m, 1 H), 1 .46 (q, J = 7.1 Hz, 2H), 1 .28 (m, 7H), 0.92 - 0.83 (m, 3H).

[0271] 4. Synthesis of iso-prepolymers

[0272] 4.1 Reference prepolymer

[0273] Lupranol 2095 (25.85 g) and Lupranol 1005 / 1 (12.95 g) were mixed in the presence of 56 mg of DABCO. The mixture was heated to 80°C under argon flow. Subsequently, a mixture of aldehyde A1 (4.13 g) and MDI (6.2 g) was added. The reaction was kept stirring for 3 hours. Experimental NCO content (2.34 %) was in line with the theoretical NCO content (2.30 %).

[0274] 4.2 Prepolymers with aldimines

[0275] Lupranol 2095 (25.85 g) and Lupranol 1005 / 1 (12.95 g) were mixed in the presence of 56 mg of DABCO. The mixture was heated to 80°C under argon flow. Subsequently, aldimine (with 0.0134 mol total imine groups) and MDI (6.2 g) were added to the mixture. The reaction was kept stirring for 3 hours. The amount of used aldimine was enough to reduce NCO content of the prepolymer by 50%.

[0276] Table with raw materials used

[0277] PP11 : As additional comparative example, Aldimine ALDR2 was utilized. However, employing the aforementioned formulation and 5.15 g of Aldimine ALDR2 led to the prepolymer undergoing gelation within a mere 15 minutes.

[0278] 4.3 Prepolymers with oxazolidines

[0279] Lupranol 2095 (24 g) and Lupranol 1005 / 1 (12.95 g) were mixed in the presence of 56 mg of DABCO. The mixture was heated to 80°C under argon flow. Above it, a mixture of oxa- zolidine (x g), diisodecyl phthalate ((6-x) g) and MDI (6.2 g) was added. The reaction was kept stirring for 2.5 hours. The amount of used oxazolidine was enough to reduce NCO content of the prepolymer by 50%.

[0280] Table with raw materials used

[0281] 5. Curing of prepolymers

[0282] For uncatalyzed systems, isocyanate prepolymer (4 g) was added into an oven-dried PTFE mold and evacuated for 3 minutes to remove the bubbles appearing due to viscosity. Following that, the polymers were conditioned at 65% relative humidity for 1 week.

[0283] For catalyzed systems, isocyanate prepolymer (4 g) was added into an oven-dried PTFE mold. Above it, 1 ml of benzoic acid solution in THF (26 mg / ml) was added and well-stirred till homogeneity (0.65 wt% of benzoic acid). Following that, the mixtures were conditioned at 23 °C and 65% relative humidity for one week.

[0284] 6. Curing DGEBA epoxy monomer with aldimines

[0285] Aldimine ALD1 (4.14 g) and DGEBA (1.95 g) were thoroughly mixed until a homogeneous mixture was achieved in a Teflon-mold. The resulting mixture was then subjected to curing at a temperature of 80 °C, within a highly humid environment (relative humidity> 95%), for one week.

[0286] 7. Results

[0287] The results are summarized in tables 1 to 4.

[0288] Table 1

[0289] Table 2 Table 3

[0290] The results show that the compositions of the invention of examples 1-9 show good storage stability, have good reactivity (skin-forming time) and cure without bubbles. They do not give off a nuisance odor, either during application or later, and in the cured state possess good mechanical properties. The latter depend greatly on the aldimine used (or on its parent polyamine) as clearly shown by the differences between the examples. In addition, it can be seen from the table above that aldimine ALD1 and ALD6 in Examples 1-4 (PP 4 and 5) do not require the use of catalyst and led to blister free curing.

[0291] Table 4 The results show that the compositions of the invention of examples 10-12 show good storage stability, have good reactivity (skin-forming time) and cure without bubbles. They do not give off a nuisance odor, either during application or later, and in the cured state possess good mechanical properties. The latter depend greatly on the oxazolidine used (or on its parent amino alcohol) as clearly shown by the differences between the examples. In addition, it can be seen from the table above that oxazolidine Ox-3 in Example 10 (PP 13) does not require the use of catalyst and led to blister free curing.

[0292] Latent curing of epoxy monomer:

[0293] The results show that aldimines can be also used to cure epoxy monomers and the compositions of the invention of Example 13 show good storage stability and does not give off a nuisance odor, either during application or later. In addition, it can be seen from the table above that aldimine ALD1 do not require the use of catalyst.

[0294] Literature cited:

[0295] US 3932357

[0296] US 4469831

[0297] US 6136942

[0298] WO 2020 / 126841

[0299] W02004 / 013088

[0300] EP 1775284

[0301] EP 1384735

[0302] WO 2017 / 108827

Claims

Claims1 . A latent hardener based on hydroxymethylfurfural which is obtainable by a process comprising the reaction of hydroxymethylfurfural or a derivative thereof and at least one amine A having at least one amino group.

2. The latent hardener according to claim 1 , wherein the hardener is an aldimine or oxazoli- dine.

3. The latent hardener according to claim 1 or 2, wherein the amine A has 1 to 4 amino groups.

4. The latent hardener according to any one of claims 1 to 3, wherein the amine is an aliphatic amine.

5. The latent hardener according to any one of claims 1 to 4, wherein the derivative of hy- droxym ethylfurfural is selected from the group consisting of ethers, esters and urethanes.

6. The latent hardener according to any one of claims 1 to 5, wherein the latent hardener has the general formula (I):wherein A is selected from the group consisting of -O-, -O(CO)-, and -O(CO)NH- groups, R° is H or a linear or branched or cyclic alkylene chain or arylalkyl residue, preferably having 2 to 300 carbon atoms, more preferable alkyl or cycloalkyl or arylalkyl residue having 1 to 40 C atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen, and optionally one or more functional groups andR is a linear or branched or cyclic alkylene chain, preferably having 2 to 300 carbon atoms, more preferable having 2 to 40 carbon atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen, or for a singly or multiply unsaturated linear or branched or cyclic hydrocarbon chain, preferably having 2 to 16 carbon atom, and n is 2, 3, 4, 5, or 6, preferably 2, 3 or 4, more preferably 2 or 3, in particular 2.

7. The latent hardener according to any one of claims 1 to 6, wherein the latent hardener has the general formula (I*):whereinA is selected from the group consisting of -O-, -O(CO)-, and -O(CO)NH- groups,R° is H or a linear or branched or cyclic alkylene chain or arylalkyl residue, preferably having 2 to 300 carbon atoms, more preferable alkyl or cycloalkyl or arylalkyl residue having 1 to 40 C atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen and optionally one or more functional groups andR is a linear or branched or cyclic alkylene chain, preferably having 2 to 300 carbon atoms, more preferable having 2 to 40 carbon atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen, or for a singly or multiply unsaturated linear or branched or cyclic hydrocarbon chain, preferably having 2 to 16 carbon atom.

8. The latent hardener according to any one of claims 1 to 5, wherein the latent hardener has the general formula (II):wherein A is selected from the group consisting of -O-, -O(CO)-, and -O(CO)NH- groups, R1is an alkyl or cycloalkyl or arylalkyl radical, preferably having 1 to 8 carbon atoms, and may have at least one ether oxygen and / or further functional groups such as for example one or more OH or NH2 groups andR is a linear or branched or cyclic alkylene chain, preferably having 2 to 300 carbon atoms, more preferable having 2 to 40 carbon atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen, or for a singly or multiply unsaturated linear or branched or cyclic hydrocarbon chain preferably having 2 to 16 carbon atom, and n is 2, 3, 4, 5, or 6, preferably 2, 3 or 4, more preferably 2 or 3, in particular 2.

9. The latent hardener according to any one of claims 1 to 5, wherein the latent hardener has the general formula (II):wherein A is selected from the group consisting of -O-, -O(CO)-, and -O(CO)NH- groups,R° is H or a linear or branched or cyclic alkylene chain or arylalkyl residue, preferably having 2 to 300 carbon atoms, more preferable alkyl or cycloalkyl or arylalkyl residue having 1 to 40 C atoms, if desired having at least one heteroatom, in particular having at least one ether oxygen and optionally one or more functional groups andR1is an alkyl or cycloalkyl or arylalkyl radical, preferably having 1 to 8 carbon atoms, and may have at least one ether oxygen and / or further functional groups such as for example one or more OH or NH2 groups10. The latent hardener according to any one of claims 1 to 9, wherein the derivative of hy- droxym ethylfurfural is selected from the group consisting of ethers, esters and urethanes having linear or branched C4-C36 alkyl chains, optionally having one or more OH or NH2 end groups.

11. A process for the preparation of a latent hardener comprising step (i)(i) reacting hydroxymethylfurfural or a derivative thereof and at least one amine A having at least one amino group.

12. The process according to claim 11 , wherein the process comprises steps (i’) and (ii’)(i’) reacting hydroxy methylfurfural and at least one amine A having at least one amino group to obtain a hydroxy methylfurfural derivative (HD1) with free OH groups,(ii’) reacting the hydroxymethylfurfural derivative (HD1 ) with a compound (C1) having functional groups reactive towards OH groups to obtain an aldimine.

13. The process according to claim 11 , wherein step (i) comprises steps (i.1) and (i.2)(1.1 ) reacting hydroxymethylfurfural with a compound (C1) having functional groups reactive towards OH groups to obtain a hydroxymethylfurfural derivative (HD2) with a functionalized OH group,(1.2) reacting the hydroxymethylfurfural derivative (HD2) obtained in step (i.1) with at least one amine A having at least one amino group to obtain an aldimine.

14. The process according to claim 11 , wherein step (i) comprises steps (i.a) and (i.b)(i.a) reacting hydroxymethylfurfural with a compound (C1 ) having functional groups reactive towards OH groups to obtain a hydroxymethylfurfural derivative (HD2) with a functionalized OH group,(i.b) reacting the hydroxymethylfurfural derivative (HD2) obtained in step (i.1) with at least one amine A having at least one amino group to obtain an oxazolidine.

15. The process according to claim 11 , wherein step (i) comprises steps (i.X) and (i.Y):(i.X) reacting hydroxymethylfurfural with a compound (C2) having at least two functional groups reactive towards OH groups to obtain a hydroxymethylfurfural derivative (HD3) with a functionalized OH group,(i.Y) reacting the hydroxymethylfurfural derivative (HD3) obtained in step (i.X) with at least one amine A having at least one amino group to obtain an oxazolidine.

16. A composition comprising(a) at least one latent hardener according to any one of claims 1 to 10, and(b) at least one monomer or prepolymer selected from the group consisting of an epoxy compound, an acrylate compound, an isocyanate compound, or an anhydride compound.

17. The composition as claimed in claim 16, wherein the composition comprises at least one polyurethane polymer containing isocyanate groups.

18. The composition according to claim 16 or 17, wherein the composition additionally comprises at least one further constituent selected from catalysts, fillers, plasticizers and solvents.

19. The composition according to any one of claims 16 to 18, wherein the composition is an adhesive or a sealant or a composition for preparing a coating, an elastomer or a foam.

20. A method comprising latently hardening compositions containing a prepolymer selected from the group consisting of an epoxy compound, an acrylate compound, an isocyanate compound, or an anhydride compound with at least one latent hardener according to any one of claims 1 to 10.21 . A method comprising latently hardening compositions containing compounds with isocyanate groups or epoxy groups with at least one latent hardener according to any one of claims 1 to 10.

22. The use of a latent hardener according to any one of claims 1 to 10 in a composition which comprises components that are reactive toward amines.

23. The use of latent hardener according to claim 22, characterized in that the components that are reactive toward amines are isocyanates.

24. The use of a latent hardener according to claim 22 or 23, characterized in that the composition is used as an adhesive, sealant, foam, coating or covering.

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