Crosslinkers

Abstract

Crosslinkers C for organic polymers R having functional groups Z, synthesised by reaction of a cyclic organic compound A having at least two, and up to four hydrogen atoms substituted by reactive atoms or functional groups V, with compounds B comprising the following parts: a functional group WB which is able to chemically bond to the cyclic organic compound A by reacting with one of the substituents V in a condensation reaction, and an at least divalent group G connected to W with a chemical bond, which group G carries at least one functional group Y that can react with functional groups Z of said organic polymer R or of an inorganic material, and an at least difunctional compound D which has at least two functional groups WD, individually referred to as WDj where j is an integer number being at least two, which groups WD can react with one of the substituents V of compound A in a condensation reaction.

Description

223080W0 Crosslinkers Field of the Invention The invention relates to crosslinkers C based on cyclic organic compounds, hereinafter referred to as "cyclic organic compounds A". The invention also relates to crosslinkable compositions comprising the crosslinkers C in combination with organic polymers which are selected from the group consisting of binder resins for coating compositions, thermoset plastic materials, natural and synthetic rubbers, organic natural and synthetic fibres, textiles made therefrom, nonwoven materials such as felts, spunbond, or paper, cardboard based on synthetic or natural organic polymers. The crosslinkers C can also be used in combination with inorganic materials such as glass, ceramics, stone, concrete, which have hydroxyl groups, or acid or basic sites on their surface or within pores which react with the crosslinkers C under modification of external and internal surfaces. Background of the Invention In the US patent 3,062,774 A, a composition of matter is disclosed which, according to claim 1, comprises the polymer of at least one polymerisable monomer referred to as a "triazinylvinyl" monomer of formula (i)wherein n is an integer having a value of at least 1 and not more than 3, R' is a radical selected from the class consisting of hydrogen and aliphatic, cycloaliphatic and aromatic hydrocarbon radicals having no more than fourteen carbon atoms therein, Y represents a monovalent radical, R" is a radical selected from the class consisting of hydrogen, halogen, and aliphatic, cycloaliphatic and aromatic hydrocarbon radicals having no more than six carbon atomstherein, and m is selected from the values of 0 and 1. Y can be hydrogen and alkyl, aryl, aralkyl, alkaryl, cycloaliphatic and heterocyclic groups and their chloro, fluoro, alkoxy, aryloxy, acyloxy derivatives, such as methyl, ethyl, propyl, isopropyl, butyl, octyl, decyl, cholorethyl, fluoropropyl, cyclohexyl, cyclopentyl, phenyl, chlorophenyl, fluorophenyl, xenyl, naphthyl, tolyl, isopropyl, phenyl, benzyl, phenethyl, phenyl, propyl, acetoxy, benzyl, ethoxy propyl, methyl naphthyl, vinyl, allyl, methallyl, allyl phenyl, etc., radicals. Y can also be hydroxyl and the alkoxy and aryloxy radicals derived from aliphatic, cycloaliphatic, aromatic and heterocyclic hydroxy compounds such as methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, decyl alcohol, phenol, the o-, m-, and p-cresols, the xylenols, naphthols, ethylene glycol, methyl glycol ether, butyl glycol ether, glycerine, pentaerythritol, hydroxy naphthalene, hydroxy pyridine, as well as the alkoxy and aryloxy radicals of hydroxy acids and esters, such as lactic acids, ethyl lactate, salicyclic acid, methyl salicylate; and in addition Y can be an amino group, NH2, or the radical of a mono- or disubstituted amino group, for example, the radicals derived from ethyl amine, methyl amine, butyl amine, nonyl amine, dimethyl amine, aniline, naphthyl amine, ethanol amine, diethanolamine, disopropanol amine, methyl aniline, piperidine, aminopyridine, hydrazine, symmetrical dimethyl hydrazine, unsymmetrical dimethyl hydrazine, as well as the radicals of the amino-acids, amino-amides, amino-nitriles,the radicals of semicarbazide and substituted semicarbazides, the guanazo radical, the radicals of urea and substituted ureas, radicals of aminoaryl sulphonamides, radicals of acyl hydrazine and substituted hydrazines, radicals of alkylene amines, the polymerizable radical of the arcylic, methacrylic, chloracrylic ester or amide of amine alcohols or dialcohols and diamines, the radicals of polymerisable aminated or hydroxylated alkylene aryl compounds, the radicals of malonic and substituted malonic esters, nitrites and amides. Homopolymers of the said triazinylvinyl monomers and copolymers with other olefinically unsaturated monomers such as styrene, acrylonitrile, ethyl methacrylate, and unsaturated alkyd resins made from polyhydric alcohols and alpha,beta-unsaturated polycarboxylic acids are also disclosed. Copolymers based on these triazinylvinyl monomers have high heat resistance, and good solvent resistance, see col.4, lines 19 to 36.In the US patent 5,807,929 A, a prepolymer is disclosed which, according to claim 1, has the formula (ii)wherein A is an n-functional anchor having n-functional nucleophilic sites, n is at least 2, L is a divalent bridge, and Z is selected from the group consisting of hydrogen, hydrocarbyl, hydrocarbyloxy, hydrocarbylthio, amido, sulphonamido, hydrocarbylamino, cyclic amino, amino, acyl, halogen and imido represented by formula (iii)wherein R1, R2, R3and R4are independently selected from hydrogen, an alkyl group having from one to twelve carbon atoms, an alkenyl group having from one to twelve carbon atoms,an alkoxy group having from one to six carbon atoms, an aryl group having from six to twenty carbon atoms, or an aralkyl group having from seven to twenty carbon atoms, and R1and R2can form together a methylene group -CH2-, or R2and R4can form together an aliphatic bridge having up to six carbon atoms which may be substituted by one or more alkyl groups having from one to twelve carbon atoms, alkoxy groups having from one to six carbon atoms, aryl groups having from six to twenty carbon atoms or aralkyl groups having from seven to twenty carbon atoms, and K is selected from the group consisting of a single bond, a divalent methylene group and a double bond, provided that K is only a double bond when R2and R4form together an aromatic ring. These prepolymers are obtained from the reaction of an imide of a dicarboxylic acid and cyanuric chloride, or from the reaction of melamine and the anhydride of a dicarboxylic acid, wherein the dicarboxylic acids include succinic acid, glutaric acid, phthalic acid, tetrahydrophthalic acid, and hexahydrophthalic acid. The same acids are also mentioned as basis for the imides. These prepolymers are useful as crosslinking agents for functional resins having active hydrogen groups (in carboxyl, hydroxyl, thiol, sulphon- amide, amido, primary amino, secondary amino, or imino groups), or epoxy groups. Crosslinking is achieved by ring-opening of the cyclic imido group, see col.7, lines 54 to 67. In the patent application US 2005 / 0075465 A1, a process is disclosed for crosslinking an organic polymer by reacting a monomer, oligomer and / or polymer with a crosslinking agent, characterized in that the crosslinking agent is of the formula I' or I"in which R' is H, C1- C12alkyl; C5- C12cycloalkyl; C2- C18alkyl which is interrupted by one or moregroup of formula II or IIIR2and R3each are - Y-T; R4is C1- C8alkyl; or phenyl; R5is C1- C12alkyl; C5- C12cycloalkyl; or C2- C18alkyl which is interrupted by one or more -O-; R6is H; OH; C1- C12alkyl; C5- C12cycloalkyl; - O - Y - T; R'6is - H; - OH; C1- C12alkyl; C5- C12cycloalkyl; - O -Y- O - CO - O - R22; R7is - H; - OH; C1- C12alkyl; C5- C12cycloalkyl; phenyl; - O - R10; - O - CO - R11; - NR12- C(O) -R11; - S - R4; R'7is - H; - O - H; C1- C12alkyl; C5- C12cycloalkyl; phenyl; OR'10; R8and R9independently are - H or C1- C12alkyl or C7- C12aralkyl; R10is C1- C12alkyl; C2- C10alkenyl; C5- C12cycloalkyl; - Y - T; or a group of the formula VR'10is C1- C12alkyl; C2- C10alkenyl; C5- C12cycloalkyl; - Y - O - CO - O - R22; R11is C1- C12alkyl; C5- C12cycloalkyl; C2- C6alkenyl; C1- C12alkoxy; R12is - H; C1- C12alkyl; C5- C12cycloalkyl; R13is C1- C18alkyl; phenyl; C7- C12alkylphenyl; benzyl; R17is H, C1- C8alkyl; C2- C8alkyl substituted by OH; C5- C12cycloalkyl; or is (CH2CH2O)m-H, wherein m ranges from 2 to 9; R21is -Y-T; and when R' is the groupR21is H or - Y - T; R22is phenyl or naphthyl, or phenyl or naphthyl each of which is substituted by C1- C18alkyl, C5- C12cycloalkyl, phenyl; R23is - H or - Y - O - CO - O -R22; R24is H or - CO - O - R22; T is - OH or - O - CO - CH=CH2or - O - CO- C(CH3)=CH2; Y is C1-C12alkylene; C3- C12alkylene substituted by OH, or - O - R13; C4- C12alkylene interrupted by - O - ; and T is linked to a primary carbon atom; Z' is C1- C12alkylene; C2- C12alkylene interrupted by - O -; - O -(C2-C12alkylene )- O -; - S -(C2- C12alkylene)- S -; Z" is C1- C12alkylene; C2- C12alkylene interrupted by - O -. The functional groups active as crosslinking sites are R2, R3, each standing for - Y - T, and R21, standing for - H or - Y - T; where T is either a hydroxyl group, or a (meth)acryloyl group. At least two of the carbon atoms of the triazine ring are chemically bound to an aromatic nucleus; see structure of I' and I". According to paragraph

[0076] , the "monomer, oligomer or polymer crosslinked by the instant process contains functional groups reactable with the compound of present formula I' selected from carboxylic, ester (including carbonate), amide, carbamate, anhydride, epoxy, isocyanate and / or reactive ethylenic double bonds. According to paragraph

[0118] , "important monomers or oligomers reactive with a hydroxyfunctional crosslinking agent [according to the invention of this said US patent application] and to be used in the instant process are oligomeric or polymeric isocyanates, isocyanurates or melamines. Examples include commercially available isocyanates, e.g. Basonat® (BASF AG), Desmodur® (Bayer AG), Tolonate® (Rhodia Syntech GmbH, Germany) etc., as well as melamines, e.g. Setamine ® (Akzo Nobel Resins BV), Cymel® (Cytec Industries Inc.), Maprenal® (Vianova Resins GmbH)". These latter are the chemicals usually described as crosslinkers, therefore, the commonly characterisation of "resin" and "crosslinker" is simply inverted herein. This can be seen, e. g., in Examples B1 and B2 where the compound according to formula I, here described as "multi-hydroxyl functional UV absorber", is admixed to a polyol component, and an isocyanate component is then added to the polyol composition to yield a clear coat formulation which is cured after application to aluminium panels. In the journal article "Circular Linkage of intramolecular multi-hydrogen bonding frameworks through nucleophilic substitutions of beta-dicarbonyls onto cyanuric chloride and subsequent tautomerisation" by Ayano Awatani and Masaaki Suzuki, RSC Adv., 2020, vol.10, pages 39033 to 39036, nucleophilic substitution of beta-dicarbonyl compounds such as malonic diethylesterand Meldrum's acid (2,2-dimethyl1,3-dioxane-4,6-dione) onto cyanuric acid is described. There is no suggestion to replace CH-acidic beta-dicarbonyl compounds at least partially by monofunctional and / or difunctional compounds having amino groups -NH2, imino groups - NH -, hydroxyl groups -OH or thiol groups -SH in the reaction with cyanuric trichloride. Object of the Invention It was the object of the invention to provide a crosslinker system that does not lead to the emission of undesirable volatile compounds, such as volatile diisocyanates, formaldehyde, or blocking agents, under conservation of the attractive properties of fast curing, and good mechanical stability of the coating film or other crosslinked compositions produced therewith. The crosslinker molecules provided by this invention are symbolised by the letter C. Summary of the Invention In the experiments on which the present invention is based, it has been found that certain derivatives of cyclic organic compounds A having at least five, and not more than six ring atoms in a ring, also including annealed ring systems comprising these cyclic organic compounds A, and having at least two, and up to four, preferably up to three hydrogen atoms bound to carbon atoms in the ring substituted by reactive atoms or reactive functional groups V, hereinafter referred to individually as V1, V2, (and if present, V3, and if present, V4), which can be the same, or can be different from each other, can be reacted with compounds B of the formula WB- G (- Y)nwhere n is at least one, and not more than three, preferably one or two, to form an intermediate product I. The compounds B comprise the following parts: afunctional group WB which is able to react with one of V1, V2, (and if present, V3, and ifpresent, V4), and a group G which is connected to WBwith a chemical bond. The group G is also connected with n functional groups Y by a chemical bond each, which functional groups Y can react with functional groups Z of an organic polymer R or with hydroxyl groups in inorganic materials. The functional groups Z may be hydroxyl groups, amino or imino groups, or acid groups, particularly carboxylic acid groups. The intermediate product I having remaining functional groups V, which can also be namedin the nomenclature used here as I' - V, in the case of one remaining functional group V in one molecule of I, or Im(- V)min the case of m remaining functional groups V in one molecule of I, is reacted in a second step with at least one of the organic compounds of groups D and M, or mixtures of these, wherein the compounds D have at least two, and preferably not more than three, functional groups WD, and wherein the compounds M have not more than one functional group WM. The compounds D can be represented by WD- Dk+1(- WD)k, where k is at least one, and preferably, not more than two, and Dk+1is an organic group having a valence of k+1. The compounds M can be represented by WM- M' wherein M' is a monovalent organic group. In the metathesis reaction of at least one of the organic compounds of groups D and M with the intermediate product I having remaining functional groups V, condensates V-WDand V-WM, respectively, are formed, together with molecules I' - D" - I', in the case that a com- pound D having two functional groups WDis used, or D"' (- I' )3, in the case that a compound D has three functional groups WDis used; or together with molecules I' - M' in the case that a compound M with one functional group WMis used. It goes without saying that the condensates V-WB, V-WDand V-WMwhich are formally formed in the metathesis reactions described here may immediately react with catalysts used, or solvents, such as water, or other reactants, and cannot always be isolated and identified. In a preferred embodiment, cyclic organic compounds A [having, in the case exemplified in the formula 1 infra, three reactive groups V, individually referred to as V1, V2and V3] can be reacted with [in the case exemplified in the formula 1 infra, two molecules of] compounds B [in this formula 1, individually referred to as B1= WB1- G1Y12 and B2= WB2- G2Y22, each of the compounds B having one reactive group WB, individually referred to as WB1, and WB2, and two reactive functional groups Y each, individually referred to as Y11and Y12of B1, and Y21andY22of B2] wherein the amount of substance of compound B is selected so that the amount of substance n(W) of functional groups WBof compound B is smaller than the amount of substance n(V) of functional groups V in compound AN, n(WB) < n(V). In the case considered here, this leads to an intermediate product I of the general formula 1 infra, where the simplecase is shown with one molecule of A being a trifunctional compound having three reactive groups V per molecule, having reacted with two molecules of B, each having one functional group WB, and where A"' stands for the residue of molecule A from which the three substituents V1, V2and V3have been removed:(Formula 1) . In this formula 1, the symbols "- V2- W2-" and "- V1- W1-" shall mean a chemical bond between the residues of molecules A and G1and A and G2. This intermediate product I exemplified by formula 1, which has, in the general case, at least a part of the substituents V in a molecule of A left unreacted, is then reacted with any one, or both of, - a monofunctional organic compound M which has exactly one functional group WM, which groups WMcan react with a substituent V (the substituent V3of this formula 1) to form a condensate V-WM, and - an at least difunctional compound D which has at least two functional groups WDjwhere j is an integer number and at least two, which groups WDjcan react with a substituent V (the substituent V3of this formula 1) to form a condensate V-WD, in a condensation reaction involving, when using M, one molecule of the compound M, and one molecule of the intermediate product I, or, when using D, one molecule of the compound D and at least two molecules of the intermediate product I, to form the crosslinker C. The at least difunctional compound D is chosen from molecules that carry at least two functional groups WDjwhich are each separated from the other functional groups by a spacer which is preferably an organic group, as detailed hereinafter. The symbols - Vk- Wk- stand here for a single bond if a condensate VkWkis formed in a condensation reaction, where k stands for 1 or 2.It is also possible, within the scope of the invention, to react the cyclic organic compounds A with at least one of compounds D and M in a first reaction step, and react the intermediate product formed therein, referred to as I2, with compound B in the second step. Another process variant comprises reaction of the cyclic organic compounds A with at least one of compounds D and M in a first reaction step, leaving a part of the substituents V originally present in A unreacted, reaction of this intermediate I3 with compound B to form a further intermediate I4, again leaving a part of the substituents V originally present in I3 unreacted, and finally, reacting I4 with a further portion of at least one of compounds D and M to prepare the crosslinker C, in which, preferably, no unreacted groups V persist. The functionality and the viscosity of the crosslinker C can be optimised in these different process variations according to the intended application, by variation of the reaction sequence and the stoichiometry in each reaction step. The crosslinker C based on the said cyclic organic compound A can be used in crosslinkable compositions. These crosslinkable compositions comprise the crosslinker A and organic polymers that have functional groups able to react with the functional groups of crosslinker A, or inorganic materials such as glass, ceramics, stone, concrete, which have hydroxyl groups, or acid or basic sites on their surface or within pores which react with the crosslinkers C under modification of external and internal surfaces. These organic polymers can be binder resins, in the case of coating or adhesive compositions, or can be elastomeric polymers used in the preparation of rubber articles, particularly engineered rubber goods, or natural or synthetic fibres such as cellulose fibres, also in the form of paper, cardboard, or engineered wood materials, or textiles such as woven, non-woven, or felt materials. Although more than three hydrogen atoms of the cyclic organic compounds A may be substituted by reactive atoms or reactive functional groups V, it has been found in the investigations upon which this invention is based, that five or more reactive atoms or reactive functional groups V in the crosslinkers C do not lead to a relevant increase in crosslinking density. Detailed Description of the Preferred EmbodimentsCyclic organic compounds A For easier understanding, a cyclic organic compound A having one of its hydrogen atoms connected to a carbon atom substituted by a monovalent functional group V is represented as V1- A' or as A'- V; a cyclic organic compound A having two of its hydrogen atoms substituted by functional groups is represented as V1- A" - V2, or as A" V2, where V stands for any one of V1and V2; a cyclic organic compound A having three of its hydrogen atoms substituted by three functional groups V is represented as A"' V3, where V stands for any one of V1and V2and V3. The individual reactive atoms or reactive functional groups V1and V2(and V3and V4if they exist) may be the same, or may be different in each case. The monovalent functional groups V are preferably halogen atoms and other functional groups which react with C-H-acidic compounds under formation of chemical bonds such as acid chlorides, particularly carboxylic acid chlorides, and sulphonyl chlorides, and particularly preferred, fluorine, chlorine, and bromine atoms. Cyclic organic compounds A comprise the families of "azoles" AN5 with nitrogen-atom containing five-membered rings or and the families of "azines" AN6 with nitrogen-atom containing six-membered rings, together hereinafter referred to as "aza-cyclic compounds AN", both containing nitrogen ring atoms, particularly derivatives thereof having functional groups which are amino groups (melamines and guanamines), reaction products thereof with aldehydes, or isocyanate groups in isocyanate trimers, which have been used as crosslinkers. Derivatives of compounds AN6 have also been described as herbicides (e.g., Simazine® which is a 1-chloro-3,5-bis-ethylamino-2,4,6-triazine, and Atrazine® which is a 1-chloro-3-ethyl- amino-5-isopropylamino-2.4.6-triazine), as optical brighteners such as bis-triazinylamino- stilbene disulphonic acids, and as building block in reactive dyes (Procion® family of dyes). Further cyclic organic compounds A include annealed or condensed aromatic, pseudoaromatic, or fully or partially hydrogenated ring systems where azoles AN5 and azines AN6 are condensed with carbocyclic groups, or other azacyclic or oxacyclic groups orthiacyclic groups, to form, e.g., quinoline, isoquinoline, cinnoline, phthalazine, quinazoline, pteridine, benzoxazole, and benzothiazole, and at least partially hydrogenated derivatives thereof. Other cyclic organic compounds are oxacyclic compounds, particularly furan derivatives, carbocyclic compounds based on benzene, condensed ring systems whereof at least one ring has a heteroatom, such as quinoxaline, and mixed heteroaromatic bodies such as oxazines, thiazines, oxazoles and thiazoles. It is also possible to use such heterocyclic organic compounds A that have two or more different heteroatoms in their ring system, whereof preferably at least one is a nitrogen atom, such as oxazoles, thiazoles, oxazines and thiazines. The preferred cyclic organic compounds A used in this invention are derived from the family of "azoles" AN5 with nitrogen-atom containing five-membered rings or and the familiy of "azines" AN6 with nitrogen-atom containing six-membered rings. Preferred azines AN6 may have from one to four carbon atoms in the heterocyclic ring, individually referred to as pyridine, or hydrogenation products thereof, particularly including piperidine, and as diazines, triazines and tetrazines having from two to four nitrogen atoms in the heterocyclic ring. The multiply unsaturated diazines of aromatic nature are pyridazine (nitrogen atoms are in the 1- and 2-position), pyrimidine (nitrogen atoms are in the 1- and 3- position), and pyrazine (nitrogen atoms are in the 1- and 4-position), and the multiply unsaturated tetrazines of aromatic nature may have nitrogen atoms in the 1-, 2-, 4-, and 5- position). A preferred class of azines AN6 having three nitrogen atoms in a six-membered ring are the saturated triazines where each nitrogen atom in the ring is bound to two carbon atoms in the ring (IUPAC name: 1,3,5-triazinanes) and also unsaturated compounds having at least one unsaturation in the ring structure, which have at least two reactive groups V bound to a carbon atom which is a member of the ring structure. Other preferred compounds AN6 are derived from diazines, such as 3,6-dichloro-4-chlorocarbonyl pyridazine, 1,4-dichloro-6- chlorocarbonyl phthalazine, 1,4-dichloro-6-chlorosulfonyl phthalazine, 2,4,5- and 2,4,6- trichloropyrimidine, their fluoro analogues 2,4,5- and 2,4,6-trifluoropyrimidine, 2,4,5,6- tetrachloropyrimidine, 2,4,6-trifluoro-5-chloropyrimidine, 2,4,6-trichloro-5-cyanopyrimidine,2,6-dichloro-5-chlorocarbonyl pyrimidine, 2,3-dichloroquinoxaline, 2,3-dichloro-6- chlorocarbonyl quinoxaline, 2,3-dichloro-6-chlorosulfonyl quinoxaline, and 4,7,8- trichlorocinnoline. Chloro substituents V in these compounds can also be replaced by fluoro substituents, or chlorocarbonyl substituents to increase the reactivity. Bromo substituents may also be used, but are less preferred. A particularly preferred compound AN6 is 2,4,6-trichloro-1,3,5-triazine, also referred to as cyanuric chloride (CC) or cyanuric trichloride (CTC), or trichlorotriazine (TCT), as shown in Formula 2: (Formula 2)and also its fluoro analogue, 2,4,6-trifluoro-1,3,5-triazine. By reacting a multifunctional reactive azine AN6 such as cyanuric chloride with a compound B having an active hydrogen atom of an acidic methine C-H group, or of an acidic methylene CH2group, where the activation results from electron-withdrawing groups in alpha-position to the carbon atom of the methine or methylene group, it is possible to replace one, two, or all three of the groups V, here chlorine atoms, by other substituents groups G-Yn, as explained supra. In the same way, it is possible, according to the invention, to react less than three substituents V with compound B, and in a second step, to react the resulting intermediate product with compound D, wherein the amount of substance of compound B is selected so that the amount of substance n(WB) of functional groups WBof compound B is smaller than the amount of substance n(V) of functional groups V in compound A, and wherein the amount of substance of compound D is selected so that the amount of substance n(WD) of functional groups WDof compound D is equal to, or greater than n(V) - n(WB).It is also possible to use 2,4-dichloro-1,3,5-triazine as azine AN6, where the carbon atom in the 6-position carries an amino group, or an alkyl or aryl group (these latter chlorinated compounds can be derived from alkanoguanamines, such as acetoguanamine or caprinogunamine, or from aromatic guanamines such as benzoguanamine. Among the azines AN6 having two heteroatoms, pyrimidine derivatives such as 2,4,6- trichloropyrimidine and 2,4,5,6-tetrachloropyrimidine, and pyridazine derivatives such as 3,4,5- and 3,4,6-trichloropyridazine are preferred. The reactivity of the chloride groups directly attached to the ring can be improved by introduction of a carbonylchloride group of formula 3: (Formula 3)represented herein by the symbolic formula -C(O)Cl, such as in 4,6-dichloropyridazine-3- carboxylic acid chloride or 3,6-dichloropyridazine-4-carboxylic acid chloride. The acylchloride group bound to a ring atom can react as substituent V, and will also enhance the activity of a chlorine atom bound to a ring atom as substituent V. Among the azines AN6 having only one heteroatom, 2,6-pyridine dicarbonyldichloride, 2- and 6-chloronicotinoylchloride and 2,6- and 4,6-dichloronicotinoylchloride are mentioned. Further, annealed azines AN6, such as quinoxalines, also referred to as benzopyrazines, or annealed azoles AN5, such as benzopyrazole derivatives, may be used. Some of the azines AN6 mentioned have been known as intermediates for the synthesis of reactive dyes. It is further possible to use azoles AN5 as heterocyclic compounds, these can be selected from the group consisting of pyrrole, pyrazole, imidazole, annealed or other multicyclic aromatic compounds having any of these as part of their molecules, and also their hydrogenated derivatives such as pyrroline, pyrazoline, imidazoline, pyrrolidine, pyrazolidine, and imidazolidine. Among the preferred azoles AN5 with activated halogen substituents, mention is made of 2,3,4,5-tetrachloropyrrole, and the compounds having more than one nitrogen ring atomwhere the chloro substituents are more activated, such as those derived from pyrazole and imidazole, e.g. 4,5-dichloroimidazole, and 3,5,7-trichloroindazole (=3,5,7-trichlorobenzo- pyrazole). Those aromatic or heterocyclic compounds with less activated halogen substituents V can also be used for the purpose of this invention if more reactive substituents are chosen, alone, or in combination with chloride substituents, a particularly preferred such substituent V is a carbonylchloride substituent, -C(O)Cl. Examples of these include 3,5-pyrazole dicarboxylic acid dichloride, and 4,5-imidazole dicarboxylic acid dichloride. It is further possible to use annealed or other multicyclic aromatic compounds having any of the mononuclear compounds mentioned supra as part of their molecules, and also their hydrogenated derivatives such as piperidine, or hydropyrazines, hydropyrimidines, and hydropyridazines. Besides symmetric triazines, also 1,2,4-triazines or their derivatives can be used as azines AN6. Those other aromatic or heterocyclic compounds with less activated halogen substituents V can also be used for the purpose of this invention if more reactive substituents are chosen, alone, or in combination with chloride substituents, a particularly preferred such substituent V is a carbonylchloride substituent, -C(O)Cl. Organic Compounds B The compounds B have the formula WB- G (- Y)iwhere i is an integer number, and is at least one, preferably one or two, and comprise the following constituents: | - one functional group WBwhich is the hydrogen atom of a methine group - C-H, or of | a methylene group >CH2, activated by a neighbouring electron-withdrawing group, commonly referred to as an "acidic CH group", able to react once with one of the substituents V1, V2, (and, if present V3and, if present V4) in the cyclic organic compound A in a condensation reaction, - one at least divalent group G connected to WBwith a chemical bond, wherein the at least divalent group G is selected from the trivalent groups methanetriyl >CH -, 1,1,1- ethane-triyl >C(CH3)- , 1,1,1-propanetriyl >C (-CH2-CH3) , 2-oxo-propane-1,1,1-triyl>C(-CO-CH3)-, 1,1,1-butane-triyl, 2-oxo-butane-1,1,1-triyl, 2-methylpropane-1,1,1-triyl,1,1,1-pentane triyl, cyanmethantriyl >C(CN)-, and the divalent groups 2-oxopropane- 1,1-diyl, 2-oxobutane-1,1-diyl, 2-oxopentane-1,1-diyl, 2,4-dioxopentane-3,3-diyl, and 3- oxobutyronitrile-2,2-diyl, - at least two functional groups Y connected to the at least divalent group G, which groups Y are different from WB, and which can react with functional hydroxyl groups Z of an organic polymer R or of an inorganic material, and wherein the functional groups Y are selected from the group consisting of carboxylic acid alkylester groups, acid groups, acid anhydride groups, alkyl carbodiimide groups, cycloalkyl carbodiimide groups, epoxide groups, aziridine groups, beta-hydroxyalkylamide groups, and groups having a carbon-carbon double bond, which carbon-carbon double bonds are optionally activated by electronegative groups. Organic compounds M Compounds M are described by formula M' - WM, where M' is a monovalent linear or branched aliphatic, or cycloaliphatic monovalent group having from one to twenty carbon atoms, connected to a divalent atom or group of atoms selected from oxygen -O-, sulphur -S-, an alkylimino -N(M°)- group, where M° is a monovalent linear or branched aliphatic, or cycloaliphatic monovalent group having from one to twenty carbon atoms, equal to, or different from M', and an imino group -NH-, where one or more nonsubsequent methylene groups may be replaced by -O- or -N(alk)- groups, where "alk" stands for aliphatic groups having from one to six carbon atoms, the functional group WMbeing the hydrogen atom of a functional group selected from the group consisting of hydroxyl groups -OH, amino groups -NH2, imino groups >NH, and thiol groups -SH. The organic compound M, if present, is preferably selected from the group consisting of methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, iso-butanol, tert-butanol, n-hexanol, 2-ethylhexanol, 2- methoxyethanol, poly(oxy-1,2-ethanediyl), -alpha-methyl-omega-hydroxy with degrees of polymerisation from 2 to 40, and mixtures of these. Particularly preferred are n-butanol, n- hexanol, and 2-ethylhexanol. Organic Compounds DPreferred compounds D comprise an aliphatic linear or branched chain having at least two, and preferably up to forty, particularly preferred, up to twenty, consecutive methylene groups -CH2- which may optionally carry substituents which may be chloro -Cl, replacing one or both of the hydrogen atoms of the methylene group, or be branched, or where further optionally, nonadjacent CH2or CHR groups may be replaced by an ether group, - O -, or an imine group, > NH or >N - R, where R may be an alkyl group of from one to four carbon atoms. The structure of the compounds D that have two or more than two functional monovalent groups WDjbound to its skeleton part is, in the case of a difunctional compound D, represented by the formula WD1- D" - WD2, and in the case of a trifunctional compound, represented by the formula 4 (Formula 4),wherein the amount of substance of compound D is selected so that the amount of substance n(WD) of functional groups WDof compound D is equal to, or greater than n(V) - n(WB). WDstands for The reaction product of two molecules of the intermediate product I with one molecule of a difunctional compound D will therefore be a crosslinker molecule C according to formula 5: Y21- G2- W2- V2- A"' - V3- WD1- D" - WD2- V3- A"' - V2- W2- G2- Y21| | | | Y22V1V1Y22| | Y11- G1- W1W1- G1- Y11| | Y12Y12(Formula 5) where -Vi - Wj - stands for a single bond in the case of a condensation step as explained supra. With the exception of groups WD, the remaining part of the molecule of D is non-reactive, or much less reactive under the circumstances of this reaction, such as, in the case of a difunctional compound D, preferably an aliphatic divalent group - (CH2)m- having at least two carbon atoms, preferably, at least four carbon atoms, most preferred, at least six carbon atoms, and not more than forty carbon atoms, which groups can optionally be branched, and wherein further optionally, one or more than one of the non-adjacent - CH2- groups can bereplaced by a tertiary amine group > N - alk, or by an ether group - O -, where the sterical hindrance is reduced due to the presence of this divalent group which is also referred to as spacer group, and therefore, a higher crosslinking efficiency is achieved. In Formula 5, a compound D has been used which has two functional groups WD, which have both reacted with a functional group V3of two different molecules of A. The first step of the reaction of a molecule of a di-substituted compound A = V2- A" - V1with a first molecule of compound B which has the structure B1= WB1- B1' = WB1- G1( -Y1i)n, where n is 1 or 2, is a condensation reaction where, in a first step, a condensate V1WB1is formed by replacing one substituent V1of A, and a chemical bond is formed between A and the first molecule B1= WB1- G1( -Y1i)nof the class of compounds B, where i assumes integer values from 1 to n, n being the number of functional groups Y1iin B1: V2- A" - V1+ WB1- G1(-Y1i)n-> V2- A" - G1(-Y1i)n+ V1WB1. The second step can then be a reaction of the product of the first step which obeys the formula V2- A" - G1(-Y1i)n- either with a second molecule B2= WB2- G2( -Y2j)mof class B where j assumes integer values from 1 to m, m being the number of functional groups Y2in B2, under formation of a condensate V2WB2: (Y1i-)n- G1- A" - V2+ WB2- G2(-Y2j)n-> (Y1i-)n- G1- A" - G2(-Y2j)m+ V2WB2, - or with a molecule D2= WD2,1- D"2- WD2,2of the class of compounds D, where D"2is used to represent the remainder of molecule D when both functional groups WD2,1and WD2,2have been removed:If the second step is the reaction with a further molecule of class B, viz., B2, a third step can be added with D3replacing substituent V3, etc. In the formula 6 infra, a cyclic organic compound A is shown whereof two substituents, labelled V1and V2, have been replaced by reaction with two molecules of class B, viz., B1and B2, and substituent V3has been replaced by reaction with one molecule of D, labelled D3here. As this compound D3is difunctional, having two functional groups referred to as WD3,1andWD3,2, one of these two (WD3,1in formula 6) having reacted with substituent V3 in a condensation reaction under formation of a chemical bond between D and the cyclic organic compound A, liberating the condensate V3- WD3,1, and forming WD3,2- D"3- as substituent on the cyclic organic compound A. This group enables binding of the reaction product of the cyclic compound A under consideration to bind to a further molecule of A. The linking groups G in the formulae of the products supra have been marked as G1if replacing substituent V1, and as G2if replacing substituent V2. The crosslinker molecule C has, therefore, two functional groups G-Yn, here referred to as G1-Ynand G2-Ym, where any Gkwith k assuming integer values of from 1 to 2, may have one or more than one functional groups Y, preferably two as shown in formula 6. The crosslinker C performs its function by participating in chemical bonds formed from reaction of the functional groups Y of the crosslinker C and the functional groups Z of the organic polymer R which has a plurality of functional groups Z bound to atoms o which are within the polymer chain repesented by "--" (particular elements of a polymer chain) or "--~" (longer part of a polymer chain) of the organic polymer R:In this figure of Formula 6, the representations of the organic polymer molecules are put in bold characters, and those of the crosslinker molecules are in normal characters to facilitate the interpretation of this figure. The crosslinker C in the figure 6 supra is based on a cyclic organic compound A which has been reacted with a first compound B1of the class B, where B1has the structure B1= W1- G1( Y1)2, under reaction of its functional group WB1with a functional group V1of the cyclic organic compound A to form a chemical bond between amolecule A where one of its functional groups V1has been replaced in a condensation reaction by the group - G1( Y1)2having two functional groups Y11and Y12according to the structure (Formula 7)and while the functional group Y11of B1is in the immediate neighbourhood of a functional group Z of the binder and thus prone to react, the functional group Y12is not in the immediate neighbourhood of a functional group Z of the binder, and is therefore not likely to react. The cyclic organic compound A has further been reacted with a second compound B2of the class B under reaction of its functional group WB2with the functional group V2of the cyclic organic compound A to form a chemical bond between A and the group - G2- (Y2)2, the structure of which is analogous to that of formula 5, with the first index 1 being replaced by the index 2, and where both functional groups Y21and Y22are able to react each with a functional group Z of the organic polymer R to form chemical bonds. In this figure 6, the substituent V3has been replaced by reaction with a molecule D under consumption of its functional group WD31, and the other functional group of D, viz., WD32is ready to chemically bind to another of the cyclic organic compounds A by reaction with one of its functional groups V of the other cyclic organic compound A. As all three substituents V1, V2, and V3of A have been replaced in this figure 6, the residue of the cyclic organic compound A in formula 6 is now represented by A"'. Functional Groups WDin Compounds D Functional groups WDof compounds D are selected from the group consisting of hydroxyl groups -OH, amino groups -NH2, imino groups >NH, and thiol groups -SH. Preferred compounds D having a functionality of two are selected from the group consisting of aliphatic diamines having from two to forty carbon atoms such as ethylene diamine, 1,2- and 1,3-diaminopropane, 1,3- and 1,4-diaminobutane, 1,3- and 1,5-diaminopentane, 2-methyl- 1,5-diaminopentane, 4-methylpentane-1,4-diamine, 3-methylpentane-1,4-diamine, 1,6- diaminohexane, 1,4-diaminocyclohexane, 2,2,4-triethylpentane-1,4-diamine, isophorone diamine (IUPAC name: 3-(aminomethyl)-3,5,5-trimethylcyclohexane-1-amine), 1,2- and 1,4- diaminocyclohexane, meta-xylylenediamine (IUPAC name: 1,1'-(1,3-phenylene)di(methan-amine)), and fatty acid dimer diamines, which can be prepared in a two-step reaction from diamines, such as ethylene diamine and two molecules of unsaturated fatty acids whereby a fatty acid diamine is formed, which is then converted to a diaminodiamide by addition of two molecules of 2-aminoethanethiol in a so-called photo-induced thiol-ene reaction, or from reaction of allylamine with an unsaturated fatty acid in the presence of dicyclohexylcarbo- diimide and 4-dimethylaminopyridine to form a fatty acid N-allylamide which is then converted to a diaminodiamide in the same way by addition of two molecules of 2- aminoethanethiol. The use of multiply unsaturated fatty acids also allows to synthesise triamines or higher amines. Other useful compounds D are polyetherdiamines based on oligomeric or polymeric oxyethylene or oxypropylene molecules having amino end groups, commercially available under the brand name "Jeffamine", and oxyamines such as ethanolamine, propanolamine, and 2-(2-aminoethoxy)ethan-1-ol. For transesterification crosslinking with a hydroxy-functional organic polymer R, an ester- functional crosslinker C is needed where the alcohol component of the ester is sufficiently volatile to be removed from the coating film under curing conditions. Crosslinkers C having at least two ester groups which can be used as crosslinkers can be prepared by reacting esters of multifunctional carboxylic acids having, in addition, a functional group WBcapable of reacting with at least one, preferably two, of the substituents V1, V2, and V3of the cyclic organic compound A. These esters of multifunctional carboxylic acids can be represented by the formula Be = WB- G Y2; in the case of dimethylmalonate, Be = H - (CH) [C(O)-O-CH3]2, where WB= H-, G = - (CH) <, and Y = - [C(O)-O-CH3]. These esters with an acidic CH group include malonic diesters, such as dialkyl malonates and 2-alkylmalonates with a linear or branched alkyl group preferably having from one to eight carbon atoms in the 2-position, and the ester groups being independently selected from the group consisting of the lower alkyl groups methyl, ethyl, n-propyl, isopropyl, n-butyl, sec- butyl, isobutyl, n-pentyl, n-hexyl, n-octyl, and 2-ethylhexyl. Higher reactivity with the cyclicorganic compound A can be provided by additional activation of the acid hydrogen atom, such as in 2-nitromalonic esters, 2-nitrosuccinic esters, or by replacing one carboxylate functional group of malonic esters by a nitrile group, -CN. It was further found in the investigations underlying the present invention that amines having both primary and secondary amino groups in their molecules can be used as compounds B if their primary amino groups are blocked by reaction with carbonyl-functional organic groups, preferably with aliphatic ketones, in other words, the groups Y of these compounds B are ketimine groups in this case. In this way, it is possible to react, e. g., one mole of a trifunctional azine AN6, such as CTC or 2,4-6-trichloropyrimidine, with less than three moles of the bisketimine of an alkylenetriamine, such as these made from diethylenetriamine (IUPAC name : N1-(2-aminoethyl)ethane-1,2-diamine), N1-(3-aminopropyl)propane-1,3-diamine, N1-(4- aminobutyl)butane -1,4-diamine, or N-(6-aminohexyl)hexane-1,6-diamine, with aliphatic ketones, preferably, acetone, methylethyl ketone, or methylisobutyl ketone. These intermediate products are reacted as described supra with a compound D to obtain a precursor for a crosslinker C, whereof the primary amino groups can be restored by addition of a stoichiometric portion of water, under elimination of the ketone. For example, the crosslinker C produced by this reaction has a total of eight primary amino groups, when using two moles of compound A, four moles of compound B and one mole of a difunctional compound D, where the two sub-units have four primary amino groups which are separated by the spacer which is a part of compound D. Such crosslinkers can be used with epoxy resins, or in the synthesis of polyureas by reaction with multifunctional isocyanates. The choice of the functional groups Y in the compounds B which become the functional groups of the crosslinker molecule C based on the cyclic organic compound A has to be made according to the functional groups Z present in the organic polymer R, or to the nature of rercative groups of the inorganic materials used. Reaction of the crosslinker C with hydroxy-functional organic polymers R (in this case, Z = - OH) is possible via a metathesis reaction, preferably by transesterification if C has estergroups as functional groups, under liberation of a volatile low-molar mass hydroxy-functional compound, or by a condensation reaction with a crosslinker C having acid functional groups, preferably under liberation of water as condensate, or by an addition reaction with a crosslinker C having acid anhydride functional groups, or by an addition reaction with a crosslinker C having isocyanate functional groups where no compounds are split off in the curing reaction. In a preferred embodiment, at least two of the functional groups Y1, Y2, ... and Ypin the crosslinker C based on the cyclic organic compound A, where p is the number of functional groups Ykin the crosslinker molecule C, k being an integer number assuming values from 1 to p, are capable of reacting with a functional group Z of the organic polymer R under formation of an addition or condensation product and formation of a chemical bond preferably selected from the group consisting of carbon-carbon bonds, carbon-nitrogen bonds, and carbon-oxygen bonds. It is noted that a value for p of exactly 2 can already suffice to effect crosslinking as the number of reactive groups Z in a organic polymer molecule or of an inorganic material is usually higher than two. It is also possible, but less preferred, to form carbon-sulphur bonds, carbon-phosphorus bonds, or carbon-silicon bonds. Preferably, the substituents V, for example, in the case of using a triazine as the azacyclic compound AN6, V1, V2, and V3, are selected from the group consisting of halogens F, Cl, Br, and I, and most preferred, Cl. It is also preferred to use carbonyl chloride groups, also referred to as carboxylic acid chloride groups, -C(O)-Cl, as substituents V. In the combination with an epoxy-functional organic polymer R, reaction of the crosslinker C is possible by addition and ring opening of the epoxide group with a crosslinker C having acid functional groups, amino functional groups, or phenol functional groups. One of the inverse reactions is the reaction of an epoxy-functional crosslinker C, such as triglycidyl isocyanurate, with an acid-functional organic polymer. Some of these reactions have already been described in the prior art, particularly transetherification in the case of hydroxy-functional binders together with amino resinsderived from melamine or guanamines, or the reaction of an epoxy-functional azine crosslinker, such as triglycidyl isocyanurate, with an acid-functional organic polymer. The use of a crosslinker C based on a cyclic organic compound A having at least two functional groups which are ester groups as crosslinker for hydroxy-functional organic polymers or other hydroxy-functional polymers has not been disclosed before. The reaction product of 2,4,6-trichloro-1,3,5-triazine and diethylmalonate has been described in an article "Circular linkage of intramolecular multi-hydrogen bonding frameworks through nucleophilic substitutions of b-dicarbonyls onto cyanuric chloride and subsequent tautomerisation" by Ayano Awatani and Masaaki Suzukiby, published in RSC Adv., 2020, 10, 39033. The use of this reaction product as crosslinker has neither been disclosed, nor has it been made obvious. Preferred Embodiments Particularly preferred crosslinkers C according to the invention are reaction products of 2,4,6- trichloro-1,3,5-triazine (cyanuric trichloride, CTC) with dimethyl malonate, dimethyl 2- methylmalonate, diethyl 2-methylmalonate, dimethyl 2-ethylmalonate, diethyl 2- ethylmalonate, dimethyl 2-hydroxymalonate, diethyl 2-hydroxymalonate, all in a molar ratio of n(ester) / n(CTC) < 3 mol, where in a further step, the intermediate product having unreacted chloro groups in each triazine molecule, being reacted with a compound D according to the invention, where the use of 1,2-diaminoethane, 1,4-diaminobutane, 1,6- diaminohexane, isophorone diamine, meta-xylylene diamine, oxyamines such as ethanolamine, propanolamine, and 2-(2-aminoethoxy)ethan-1-ol, and polyetherdiamines based on oligo-ethylene glycol, oligo-propylene glycol, and oligo-1,4-butylene glycol, all with terminal primary amino groups, and also fatty acid dimer diamines as mentioned supra is preferred. The following embodiments have been found useful for the purpose of the invention: Embodiment1. A crosslinker C obtainable by reaction of- a cyclic organic compound A which is selected from the group consisting of azacyclic organic compounds AN having five (AN5) or six (AN6) atoms in one ring, whereof at least one is a nitrogen atom, and at least two are carbon atoms, having at least two, and up to four, preferably two or three, substituents V bound to different ring atoms which are reactive atoms or functional groups, hereinafter referred to individually as V1, V2, (and, if present V3and, if present V4), which substituents V can be the same, or can be different from each other, and are selected from the group consisting of halogen atoms -F, -Cl, -Br, and from halocarbonyl groups -C(O)- Hal, where -Hal is selected from the group consisting of halogen atoms -F, -Cl, and -Br, - compounds B comprising the following parts: one atom or functional group WBwhich is able to react once with one of V1, V2, (and, if present V3and, if present V4) in a metathesis or condensation reaction; and one at least divalent group G connected to WBwith a chemical bond, wherein the at least divalent group G is selected from the trivalent groups of 1,1,1- alkyltriyls, preferably methanetriyl >C(H)-, 1,1,1-ethanetriyl >C(CH3)-, 1,1,1-propanetriyl >C(CH2-CH3)-, 1,1,1-butanetriyl >C(CH2-CH2-CH3)-, 1,1,1-pentanetriyl >C(CH2-CH2-CH2- CH3)-, 2-oxoalkyl-1,1,1-triyls, preferably 2-oxopropane-1,1,1-triyl >C(CO-CH3)-, cyanomethan- triyl >C(CN)-, and from the divalent groups 2-oxoalkane-1,1-diyls, preferably 2-oxopropane- 1,1-diyl, 2-oxobutane-1,1-diyl, 2-oxopentane-1,1-diyl, and 2,4-dioxopentane-3,3-diyl, and 3- oxobutyronitril-2,2-diyl, and which group G carries at least one, preferably one or two, functional groups Y that can react with functional hydroxyl groups Z of an organic polymer R or of an inorganic material, wherein the group WBof compound B is one hydrogen atom of an acidic methine group CH or acidic methylene group CH2, and wherein the groups Y of compound B are selected from the group consisting of carboxylic acid alkylester groups -C(O)- O-R; acid groups -C(O)-O-H; epoxide groups; aziridine groups; beta-hydroxyalkylamide groups -C(O)-N(H)-CH2-CH2-OH; acid anhydride groups -C(O)-O-(C)-O-Ri; alkyl carbodiimide groups -N=C=N-Rii, cycloalkyl carbodiimide groups -N=C=N-Riii, where any ofR, Ri, and Riiare, independently of each other, alkyl groups having from one to six carbon atoms, and Riiiare cycloalkyl groups having from five to eight carbon atoms; groups having a carbon-carbon double bond, optionally activated by electronegative groups,- an at least difunctional compound D which has at least two functional groups WD, individually referred to as WDjwhere j is an integer number being at least two, which groups WDare selected from the group consisting of a hydrogen atom from amino groups -NH2, imino groups -NH-, hydroxyl groups -OH, and thiol groups -SH, with at least one amino group or at least one hydroxyl group being present in compound D, and which can react with one of the substituents V of compound A in a metathesis or condensation reaction, wherein the compound D has the structure Dn(WDj)nwhere Dnstands for a n-valent organic group which has the structural formula X1-E2-X2for n=2, and X1-E3-X3for n=3, where X1, X2, and X3| X2are all divalent groups, selected, independently of each other, from an oxy group or ether group -O-, an imino group -N(H)- or >N(R"), , an amino group, or a sulfide group of thio group -S-, and E2is a divalent linear or branched or cyclic aliphatic group having from two to forty carbon atoms where one or more of phenylene groups -(C6H4)-, methylmethylene groups >C(CH3)-H, ether groups -O-, imino groups -NH-, or alkylimino groups >N–R" may be inserted into the aliphatic chain, where R" may be any alkyl group having at least one carbon atom, and up to twenty carbon atoms, and where none of ether groups-O-, imino groups -NH-, and alkylimino groups >N–R may follow directly in sequence, and wherein E3 is atrivalent branched or cyclic aliphatic group having from two to forty carbon atoms where one or more of phenylene groups -(C6H4)-, alkylmethylene groups >C(R)-H, ether groups -O-, imino groups -NH-, or alkylimino groups >N–R' may be inserted into the aliphatic chain, where R and R' may be, independently of each other, any alkyl group having at least one carbon atom, and up to twenty carbon atoms, and where none of ether groups-O-, imino groups -NH-, and alkylimino groups >N–R' may follow directly in sequence, and wherein - the amount of substance of compound B is selected so that the amount of substance n(WB) of functional groups WBof compound B is smaller than the amount of substance n(V) of functional groups V in compound A, and wherein the amount of substance of compound D is selected so that the amount of substance n(WD) of functional groups WDof compound D is equal to, or lower than n(V) - n(WB).Embodiment 2. The crosslinker C of embodiment 1 wherein the ratio n(WB) / n(V) of the amount of substance n(WB) of functional groups WBof compound B and the amount of substance n(V) of functional groups V in compound A is: 0.1 mol / mol # n(WB) / n(V) # 0.9 mol / mol; preferably 0.2 mol / mol # n(WB) / n(V) # 0.8 mol / mol; and particularly preferred, 0.3 mol / mol# 0.7 mol / mol. Embodiment 3. The crosslinker C of any one of embodiment 1 and embodiment 2 wherein the cyclic organic compound A is selected from the group consisting of - azacyclic organic compound AN5 having one nitrogen atom in a ring, and all other ring atoms are carbon atoms, - azacyclic organic compounds AN5 having two nitrogen atoms in a ring which are preferably located in positions 1 and 2, or in positions 1 and 3, and all other ring atoms are carbon atoms, and - azacyclic organic compounds AN5 having three nitrogen atoms in a ring which are preferably located in positions 1, 2, and 3, or in positions 1, 2, and 4, and all other ring atoms are carbon atoms, and the azacyclic organic compounds AN6 are selected from the group consisting of - azacyclic organic compounds AN6 having one nitrogen atom in a ring, and all other ring atoms are carbon atoms, - azacyclic organic compounds AN6 having two nitrogen atoms in a ring which are preferably located in positions 1 and 2, or 1 and 3, or 1 and 4, and all other ring atoms are carbon atoms, - azacyclic organic compounds AN6 having three nitrogen atoms in a ring which are preferably located in the 1, 3, and 5 positions, and all other ring atoms are carbon atoms, and - azacyclic organic compounds AN6 having four nitrogen atoms in a ring which are preferably located in positions 1, 2, 4, and 5, and all other ring atoms are carbon atoms. Embodiment 4. The crosslinker C of any one of embodiments 1, and 2, and 3, wherein the substituents V are the same, or are different from each other, and are selected from thegroup consisting of -Cl, and chlorocarbonyl groups -C(O)- Cl. Embodiment 5. The crosslinker C of any one of embodiments 1, and 2, and 3, and 4, wherein the group WBof compound B is a hydrogen atom of an acidic methine group CH or of an acidic methylene group CH2,activated by neighbouring electronegative groups which are preferably carbonyl, carboxyl, cyano, trifluoromethyl, sulphonyl, or nitro groups. Embodiment 6. The crosslinker C of any one of embodiments 1, and 2, and 3, and 4, and 5, wherein the at least divalent group G is selected from the trivalent groups methanetriyl >C(H)-, 1,1,1-ethanetriyl >C(CH3)-, 1,1,1-propanetriyl >C(CH2-CH3)-, 1,1,1-butanetriyl >C(CH2- CH2-CH3)-, 1,1,1-pentanetriyl >C(CH2-CH2-CH2-CH3)-, cyanomethantriyl >C(CN)-, and 2- oxopropane-1,1,1-triyl >C(CO-CH3)-, and from the divalent groups 2-oxopropane-1,1-diyl, 2- oxobutane-1,1-diyl, 2-oxopentane-1,1-diyl, 2,4-dioxopentane-3,3-diyl, and 3-oxobutyronitril- 2,2-diyl. Embodiment 7. The crosslinker C of one of embodiments 1, and 2, and 3, and 4, and 5, and 6, wherein the groups Y of compounds B are preferably selected from the group consisting of carboxylic acid alkylester groups C(O)-O-Alk, where Alk- is the alkyl group of the alkylester and is selected from the group consisting of methyl, ethyl, isopropyl, n-propyl, n-butyl, sec-butyl, iso-butyl and tert-butyl groups. Embodiment 8. The crosslinkers C of any one of embodiments 1, and 2, and 3, and 4, and 5, and 6, and 7, wherein the groups WDof compound D are, independently of each other, a hydrogen atom from the group consisting of hydroxyl groups -OH, and amino groups -NH2. Embodiment 9. The crosslinkers C of any one of embodiments 1, and 2, and 3, and 4, and 5, and 6, and 7, and 8, wherein the cyclic organic compound A is trichlorocyanuric acid (cyanuric trichloride or 2,4,6-trichloro-1,3,5-triazine), the compound B is selected from the group consisting of diethyl malonate, diethyl-2-methylmalonate, diethyl-2-ethylmalonate, diethyl-2-hydroxymalonate, diethyl-3-hydroxyglutarate, and the corresponding dimethylesters, and the compound D is selected from the group consisting of 1,2-dihydroxyethane (ethylene glycol), 1,2-dihydroxypropane, 1,3-dihydroxypropane, 1,4-diyhdroxybutane, 1,6- dihydroxyhexane, oligomeric or polymeric ethylene glycols or propylene glycols, or copolymers thereof, 1,2-diaminoethane, 1,4-diaminobutane, 1,6-diaminohexane, isophoronediamine (IPDA, 3-aminomethyl-3,5,5-trimethylcyclohexane-1-amine), meta- xylylenediamine (MXDA, 1,1'-(1,3-phenylene)di(methanamine)), oligomeric and polymeric 2- aminopropoxy-(propoxy)i-propane-2-amines where i can assume integer values from 1 to 80, and where propoxy and propane may also be replaced by ethoxy and ethane groups, and 2- (2-aminoethoxy)ethanol, and mixtures of these. Embodiment 10. A process for preparing the crosslinker C of any one of embodiments 1, and 2, and 3, and 4, and 5, and 6, and 7, and 8, and 9, wherein - in a first step, a cyclic organic compound A as defined in embodiment 1 is reacted with compounds B as defined in embodiment 1 under formation of an intermediate product I, wherein - the amount of substance of compound B is selected so that the amount of substance n(WB) of functional groups WBof compound B is smaller than the amount of substance n(V) of functional groups V in compound A, and wherein the reaction is - a condensation reaction under formation of a condensate VWBand formation of a chemical bond between the atoms of A and B that were carrying the groups V and WB, and - wherein, in a second step, the product I of the first reaction step is reacted with an at least difunctional compound D as defined in embodiment 1 which has at least two functional groups WDjwhere j is an integer number and at least two, which groups WDjcan react with one of the substituents V in an addition or condensation reaction to form the crosslinker C, wherein the amount of substance of compound D is selected so that the amount of substance n(WD) of functional groups WDof compound D is equal to, or greater than n(V) - n(WB). Embodiment 11. The process of embodiment 10 wherein the ratioof the amount of substance n(WB) of functional groups WBof compound B and the amount of substance n(V) of functional groups V in compound A is:0.5 mol / mol # n(WB) / n(V) # 0.9 mol / mol; preferably 0.60.8 mol / mol; and particularly preferred, 0.65 mol / mol # n(WB) / n(V) # 0.75 mol / mol. Embodiment 12. The crosslinker of any one of embodiments 1, and 2, and 3, and 4, and 5, and 6, and 7, and 8, and 9, wherein at least a part of the compound D is replaced by a monofunctional compound M having the structure WM- M’, where WMis the hydrogen atom of groups selected from the group consisting of a hydroxyl group -OH, a thiol group -SH, an amino group -NH2, and an imino group >N-H, and where -M’ is -X4-E4, where X4 are divalent groups, selected from an oxy group or ether group -O-, an imino group -N(H)- or >N(R"'), an amino group, or a sulfide group of thio group -S-, and E4is a monovalent linear or branched or cyclic aliphatic group having from two to forty carbon atoms where one or more of phenylene groups -(C6H4)-, methylmethylene groups >C(CH3)-H, ether groups -O-, imino groups -NH-, or alkylimino groups >N–R"' may be inserted into the aliphatic chain, where R"' and Rivmay, independent from each other, be any alkyl group having at least one carbon atom, and up to twenty carbon atoms, and where none of ether groups-O-, imino groups -NH-, and alkylimino groups >N–Rivmay follow directly in sequence wherein the amount of M is chosen such that the amount of substance of functional groups WMis at least 0.1 × ( n(V) - n(WB) ), and not more than 0.9 × ( n(V)- n(WB) ). Embodiment 13. A process for preparing the crosslinker C of one of embodiments 1, and 2, and 3, and 4, and 5, and 6, and 7, and 8, and 9, and 12, wherein - in a first step, a cyclic organic compound A as defined hereinbefore is reacted with - compounds D as defined hereinbefore under formation of an intermediate product I2, wherein - the amount of substance of compound D is selected so that the amount of substance n(WD) of functional groups WDof compound D is smaller than the amount of substance n(V) of functional groups V in compound A, and wherein the reaction is - a condensation reaction under formation of a condensate VWDand formation of a chemical bond between the atoms of A and D that were carrying the groups V and WD, and- wherein, in a second step, the product I2 of the first reaction step is reacted with a compound B as defined hereinbefore to form the crosslinker C, wherein the amount of substance of compound B is selected so that the amount of substance n(WB) of functional groups WBof compound B is at least equal to n(V) - n(WD). Embodiment 14. The process of embodiment 13, wherein at least a part of the compound D is replaced by a monofunctional compound M having the structure WM- M’, where M’ is selected from alkyl groups having from one to twenty carbon atoms, and WMis selected from the group consisting of hydroxyl groups -OH, amino groups -NH2, imino groups >NH, and thiol groups -SH, and wherein the amount of M is chosen such that the amount of substance of functional groups WMis at least 0.1 × ( n(V) - n(WB) ), and not more than 0.9 × ( n(V) - n(WB) ). Embodiment 15. A process for preparing the crosslinker C of one of embodiments 1, and 2, and 3, and 4, and 5, and 6, and 7, and 8, and 8, and 9, and 12, wherein - in a first step, a cyclic organic compound A as defined in embodiment 1 is reacted with - compounds D as defined in embodiment 1, wherein at least a part of the compound D may be replaced by a monofunctional compound M having the structure WM- M’, where M’ is selected from alkyl groups having from one to twenty carbon atoms, and WMis selected from the group consisting of hydroxyl groups -OH, amino groups -NH2, imino groups >NH, and thiol groups -SH, under formation of an intermediate product I3, - wherein the amount of substance of compounds D and M is selected so that the sum n(WD) + n(WM) of the amount of substance n(WD) of functional groups WDof compound D andthe amount of substance n(WM) of functional groups WMof compound M is smaller than theamount of substance n(V) of functional groups V in compound A, and wherein the reaction is a condensation reaction under formation of condensate VWDand VWMand formation of a chemical bond between the atoms of A and one or more of D and M that were carrying the groups V and WD, and / or WM, and - in a second step, the product I3 of the first reaction step is reacted with a compound Bas defined in embodiment 1, wherein the amount of substance of compound B is selected so that the amount of substance n(WB) of functional groups WBof compound B is less than the remaining amount of substance n(V) of functional groups V in the product I3 of the first reaction step, to form an intermediate product I4, and - in a third step, the intermediate product I4 is reacted with a further portion of a compound D, wherein at least a part of the compound D may be replaced by the said monofunctional compound M, to form a crosslinker C, wherein the amount of substance of compounds D and / or M is selected so that the sum n(WD) + n(WM) of the amount of substance n(WD) of functional groups WDof compound D and the amount of substance n(WM) of functional groups WMof compound M is equal to, or up to 50 % higher than, the remaining amount of substance n(V) of functional groups V in the product I4 of the second reaction step. Embodiment 16. A method of use of the crosslinker C of one of embodiments 1, and 2, and 3, and 4, and 5, and 6, and 7, and 8, and 9, and 10, and 13, or made by the process of one of embodiments 10, and 11, and 13, and 14, and 15, together with - organic polymers which are selected from the group consisting of binder resins for coating compositions, elastomeric materials, organic natural or synthetic fibres, textiles made therefrom, nonwoven materials such as felts, spunbond, or paper, cardboard based on synthetic or natural organic polymers, where the crosslinkers react with functional groups present in the organic polymer to improve the physical, mechanical or chemical properties , or modify surface or adhesion properties, and / or - inorganic materials such as glass, ceramics, stone, concrete, which have hydroxyl groups, or acid or basic sites on their surface or within pores which react with the crosslinkers C under modification of external and internal surfaces, which method comprises mixing the crosslinker C with one or more of the said organic polymers and / or inorganic materials, and wherein the functional groups Z of the said organic polymers are selected from the group consisting of hydroxy groups, amino groups, imino groups, and thiol groups. Embodiment 17. The method of use of embodiment 16 wherein the crosslinker C is usedtogether with an organic polymer R by mixing the crosslinker C with the organic polymer R to obtain a coating composition or a moulding composition. Embodiment 18. The method of use of embodiment 17 comprising applying the coating composition, optionally in the presence of a catalyst, to a surface of textiles, nonwoven materials such as felts, spunbond, paper, or cardboard based on synthetic or natural organic polymers, inorganic materials such as glass, ceramics, stone, concrete, or coated metal sheets which have hydroxyl groups, or acid or basic sites on their surface or within pores, followed by a drying step at room temperature (25 °C) or elevated temperature, or impregnating porous material with the said mixture, also followed by a drying step. Embodiment 19. The method of use of embodiment 17 wherein the crosslinker C is separately mixed and compounded with an elastomeric material, and this compound is added during the compounding process of rubber compounds. Use of the Crosslinkers It has been found in the experiments underlying the present invention that the crosslinkers according to the present invention can be used together with organic polymers, particularly with binder resins for coating compositions where they are used in the so-called one pack systems to react with the binder resins upon heating, and formation of a three-dimensionally crosslinked coating film, with rubber materials in the compounding process to enhance the curing or vulcanisation speed, improve the chemical and physical properties, particularly the mechanical properties such as stiffness and resilience, of the vulcanised rubber, and increase the adhesion of the vulcanised rubber to steel and textile fibres, with organic natural or synthetic fibres, textiles made therefrom, nonwoven materials such as felts, spunbond, or paper, or cardboard based on synthetic or natural organic polymers, where the crosslinkers react with functional groups present in the organic polymer to improve the mechanical, chemical and thermal stability, and reduce the humidity or water solvent uptake, or modify surface properties. Inorganic materials such as glass, ceramics, stone, concrete, or coated metal sheets which havehydroxyl groups, or acid or basic sites on their surface or within pores which react with the crosslinkers C under modification of external and internal surfaces. The crosslinkers C can also be used in the preparation of thermoset plastic materials, for improvement of the wet strength of paper and cardboard, for textile finishing, for surface modification of fibres, films, and fabrics, as vulcanisation agent, accelerant, or additive in rubber materials, for impregnation of decor films, and of porous materials such as wood, stone, concrete, ceramics, leather, felts, non-wovens, and fibre board. For coating purposes, or other surface modification, it suffices to apply the crosslinkers C together with an appropriate binder material, optionally in the presence of appropriate catalysts such as transesterification catalysts, which may comprise transition metal salts, acids, or basic cata- lysts, to a surface, and drying at room temperature or elevated temperature. For porous materials, it is recommended to impregnate these under application of reduced pressure. The invention is further illustrated by the following examples which shall not be construed to limit the scope of the invention. Examples SI units are used throughout the examples. The following symbols are used: M molar mass of a chemical compound; M = m / n where m is the mass of the compound, and n is the amount of substance of the compound, in a sample or portion wBis the mass fraction of a substance B in a mixed phase, wB= mB / mÓwhere mBis the mass of compound B in the mixed phase, andis the total mass of the mixed phase Example 1 A solution of 27.7 g (0.15 mol) of cyanuric chloride (M = 184.404 g / mol) in 200 mL of 1,4- dioxane was prepared at room temperature (23 °C) and cooled upon complete dissolution to a temperature below 7 °C. Then, 48.1 g (0.3 mol) of diethylmalonate were added under stirring, followed by dropwise addition of 24 g of an aqueous solution of sodium hydroxide having a mass fraction of solute of 50 % (corresponding to an amount of substance of NaOHof 0.3 mol) in a way that a temperature of 7 °C was not exceeded. After complete addition, the reaction mixture was heated to 40 °C and maintained at this temperature for two hours under continued stirring. Thereafter, the mixture was cooled again to a temperature below 7 °C, and 4.5 g (0.075 mol) of ethylenediamine were added dropwise under continued stirring in a way that the temperature did not exceed 7 °C. Subsequently, 12 g of an aqueous solution of sodium hydroxide (as supra; 0.15 mol) were slowly added, keeping the temperature below 7 °C. The reaction mixture was then heated to 40 °C and kept at this temperature for two hours under continued stirring. The mixture was then heated to 60 °C and maintained for one further hour at this temperature before it was cooled down to 30 °C. Thereafter, 160 g of water were added, and the pH was adjusted to 7.3 by dropwise addition of an aqueous solution of hydrochloric acid (having mass fraction of solute of 32 %). Water and dioxane were removed in vacuo, and 78 g of a yellow crude product (including salt) were dissolved in a mixture of 250 g of butyl acetate and 500 g of distilled water at 90 °C. The organic phase was separated and washed twice with distilled water at 90 °C. The combined aqueous phases were washed once with 100 g of butyl acetate at 90 °C. The solvent of the organic phase was removed in vacuo, and 43 g of the yellow product were isolated. The product is a viscous fluid at 80 °C, but solidifies at room temperature (23 °C). Example 2 A solution of 27.7 g (0.15 mol) of cyanuric chloride in 200 mL of 1,4-dioxane was prepared at room temperature (23 °C) and cooled upon complete dissolution to a temperature below 7 °C. Then, 48.1 g (0.3 mol) of diethylmalonate were added under stirring, followed by dropwise addition of 24 g of an aqueous solution of sodium hydroxide having a mass fraction of solute of 50 % (corresponding to an amount of substance of NaOH of 0.3 mol) in a way that a temperature of 7 °C was not exceeded. After complete addition, the reaction mixture was heated to 40 °C and maintained at this temperature for two hours under continued stirring. Thereafter, the mixture was cooled again to a temperature below 7 °C, and 8.7 g (0.075 mol) of 1,6-diaminohexane (hexamethylenediamine) was added dropwise under continued stirring in a way that the temperature did not exceed 7 °C. Subsequently, 12 g of an aqueous solution of sodium hydroxide (as supra; 0.15 mol) were slowly added, keeping the temperature below7°C. After this, the reaction mixture was heated to 40 °C and kept at this temperature for thirty minutes. The mixture was then heated to 60 °C and maintained for one hour at this temperature before it was cooled down to 30 °C. Thereafter, 160 g of water were added and the pH was adjusted to 7.3 by dropwise addition of an aqueous solution of hydrochloric acid (having mass fraction of solute of 32 %). Water and dioxane were removed in vacuo, and 78 g of a yellow crude product (including salt) were dissolved in 250 g of butyl acetate and 500 g of distilled water at 90 °C. The organic phase was separated and washed twice with distilled water at 90 °C. The combined aqueous phases were washed once with 100 g of butyl acetate at 90 °C. Afterwards, the solvent of the organic phase was removed in vacuo, and 45 g of the yellow product were isolated. In a hot state the product is a viscous fluid but solidifies at room temperature (23 °C). Example 3 A solution of 27.7 g (0.15 mol) of cyanuric chloride in 200 mL of 1,4-dioxane was prepared at room temperature (23 °C) and cooled upon complete dissolution to a temperature below 10 °C. Then, 48.1 g (0.3 mol) of diethylmalonate were added under stirring, followed by dropwise addition of 24 g of an aqueous solution of sodium hydroxide having a mass fraction of solute of 50 % (corresponding to an amount of substance of NaOH of 0.3 mol) in a way that a temperature of 10 °C was not exceeded. After complete addition, the reaction mixture was heated to 40 °C and maintained at this temperature for two hours under continued stirring. Thereafter, the mixture was cooled again to a temperature below 7 °C, and 12 g of an aqueous solution of sodium hydroxide (as supra; 0.15 mol) were slowly added, keeping the temperature below 7°C. Subsequently, 16.1 g (0.15 mol) of 2-(2-aminoethoxy)ethanol were added dropwise under continued stirring in a way that the temperature did not exceed 10 °C. After this, the reaction mixture was heated to 40 °C and kept at this temperature for two hours under continued stirring. The mixture was heated to 60 °C and maintained for one hour at this temperature before it was cooled down to 30 °C. Thereafter, 160 g of water were added and the pH was adjusted to 7.3 by dropwise addition of an aqueous solution of hydrochloric acid having a mass fraction of solute of 32 %. Water and dioxane were removed in vacuo, and the yellow crude product (including salt) was dissolved in 250 g of butyl acetate and 500 g ofdistilled water at 90 °C. The organic phase was separated and washed twice with distilled water at 90 °C. The combined aqueous phases were washed once with 100 g of butyl acetate at 90 °C. The organic phases were combined, and the solvent was removed in vacuo. Finally, 49 g of a yellow product were isolated. The product is a viscous fluid at room temperature (23 °C), but starts to crystallise after resting a few days, and solidifies at room temperature after several weeks of storage. Example 4 A solution of 27.7 g (0.15 mol) of cyanuric chloride in 200 mL of 1,4-dioxane was prepared at room temperature (23 °C). Then, 14.5 g (0.195 mol) of n-butanol were added under stirring, followed by dropwise addition of 24 g of an aqueous solution of sodium hydroxide having a mass fraction of solute of 50 % (corresponding to an amount of substance of NaOH of 0.3 mol) at room temperature (23 °C). The reaction mixture was then heated to 40 °C and maintained at this temperature for two hours under continued stirring. Thereafter, the mixture was cooled to 30 °C and 40.8 g (0.255 mol) of diethylmalonate and 40 ml of 1,4-dioxan were added. Subsequently, 12 g of an aqueous solution of sodium hydroxide having a mass fraction of solute of 50 % (corresponding to an amount of substance of NaOH of 0.15 mol) were added dropwise, keeping the temperature below 30 °C. The mixture was heated on 40 °C and maintained for 120 min at this temperature. Thereafter, 160 g of water were added and the pH was adjusted to 7.0 by adding an aqueous solution of hydrochloric acid having a mass fraction of solute of 32 %. Water and dioxan were removed by distillation under reduced pressure, and the crude product (including salt) was dissolved in a mixture of 250 g of butyl acetate and 500 g of distilled water at 90 °C. The organic phase was separated and washed twice with distilled water at 90 °C. The combined aqueous phase was washed once with 100 g of butyl acetate at 90 °C. The organic phases were combined, and the solvent was removed by distillation under reduced pressure. Finally, 43 g of a slightly yellow liquid was isolated. Example 5 A solution of 27.7 g (0.15 mol) of cyanuric chloride in 200 mL of 1,4-dioxane was prepared at room temperature (23 °C). Then, 14.5 g (0.195 mol) of n-butanol were added, followed by thedropwise addition of 24 g of an aqueous solution of sodium hydroxide having a mass fraction of solute of 50 % (corresponding to an amount of substance of NaOH of 0.3 mol) at romm temperature (23 °C). The reaction mixture was then heated to 40 °C and was maintained at this temperature for 120 min. After cooling down to 30 °C, 40.8 g (0.255 mol) of diethylmalonate and 40 ml 1,4-dioxan were added. Subsequently, 12 g of an aqueous solution of sodium hydroxide having a mass fraction of solute of 50 % (corresponding to an amount of substance of NaOH of 0.15 mol) were added dropwise, keeping the temperature below 30 °C. The mixture was then heated to 40 °C and maintained for 120 min at this temperature.16.1 g (0.15 mol) of 2-(2-aminoethoxy)-ethanol was then added dropwise under continued stirring in a way that the temperature did not exceed 30 °C. Then, the reaction mixture was heated to 60 °C and kept at this temperature for 60 min. Thereafter, 160 g of water were added, and the pH was adjusted to 7.0 by adding an aqueous solution of hydrochloric acid having a mass fraction of solute of 32 %. Water and dioxan were removed by distillation under reduced pressure, and the crude product (including salt) was dissolved in a mixture of 250 g of butyl acetate and 500 g of distilled water at 90 °C. The organic phase was separated and washed twice with distilled water at 90 °C. The combined aqueous phase was washed once with 100 g of butyl acetate at 90 °C. The organic phases were combined, and the solvent was removed by distillation under reduced pressure. Finally, 48 g of a slightly yellow liquid was isolated. Application Tests Materials used: Crosslinker Resins: - Maprenal® BF 892 (comparative resin; Prefere Melamines GmbH; highly reactive n- butylated benzoguanamine formaldehyde resin, mass fraction of resin 68 % in n- butanol as solvent) - Product of Example 1 (formaldehyde free; undiluted) - Product of Example 2 (formaldehyde free; undiluted) - Product of Example 3 (formaldehyde free; undiluted) Binder Resin: Dynapol® LH 818 (hydroxy-functional polyester resin; Evonik Industries AG; data as published in January 2021: glass transition temperature 30 °C [determined by DynamicScanning Calorimetry]; hydroxyl value 20 mg / g [DIN EN ISO 4629-2]; acid value 1 mg / g [DIN EN ISO 2114]; molar mass 6000 g / mol [calculated from hydroxyl and acid values]; dissolved in a mixture of solvent naphtha 150 and solvent naphtha 200, undisclosed mass ratio; mass fraction of solids 50 %; data taken from data sheet of supplier) Crosslinker resin solutions were prepared by separately dissolving the resins of examples 1, 2, and 3 in a mixture (hereinafter referred to as "solvent mixture") of n-butanol (1 kg), Solvent Naphtha 150 (2 kg; mixed aromatic hydrocarbons as supplied by Dana Lubricants Factory LLC, composed of C9- to C11- aromatic hydrocarbons, predominantly C10-aromatic hydrocarbons; distillation temperature range from 180 °C to 185 °C according to ASTM D86) and Solvent Naphtha 100 (2.6 kg; mixed aromatic hydrocarbons as supplied by Dana Lubricants Factory LLC, composition as mass fractions: 1,2,4-trimethyl benzene [20 % to 45 %], 1,3,5-trimethyl benzene [8 % to 15 %], mixed ethyltoluenes [25 % to 35 %]; sum of mass fractions of C9- aromatic hydrocarbons is 90 %; distillation temperature range from 158 °C to 165 °C according to ASTM D86) to a mass fraction of solids to 50 %. A volume containing 3.75 g of dissolved crosslinker each was used in the preparation of the varnish. 7.5 g of the crosslinker solutions (comprising 3.75 g of crosslinker) were admixed to 30 g of the binder resin solution (comprising 15 g of polyester resin) in each case to prepare the varnish. For the comparative example, 5.2 g of the solution of the comparative crosslinker (comprising 3.75 g of crosslinker) was diluted with 2 g of the solvent mixture as described supra, and then admixed to 30 g of the binder resin solution (comprising 15 g of polyester resin) to prepare the comparative varnish. These varnishes were applied onto a tin plate using a doctor blade in a wet thickness of 50 µm. The drying conditions were: 8 min at room temperature (23 °C), and forced drying for 10 min at 180 °C or for 10 min at 200 °C, respectively. Up to 3 substrates were coated for each experiment.The following results were found: Dry Film Thickness, forced drying at 180 °C Crosslinker Panel 1 Panel 2 Panel 3 comparison (BF 892) 11 µm 11 µm 12 µm Product of Example 1 11 µm 11 µm 11 µm Product of Example 2 11 µm 12 µm 12 µm Product of Example 3 11 µm 12 µm 11 µm Dry Film Thickness, forced drying at 200 °C Crosslinker Panel 1 Panel 2 Panel 3 comparison (BF 892) 10 µm 11 µm 11 µm Product of Example 1 11 µm 11 µm 12 µm Product of Example 2 11 µm 12 µm 10 µm Product of Example 3 12 µm 12 µm 11 µm Pendulum Hardness, measured at room temperature (23 °C) after resting for 24 h, according to DIN EN ISO 1522 with a König pendulum at a room temperature of (23 ± 2) °C and a relative humidity of (50 ± 5) % Crosslinker forced drying at 180 °C forced drying at 200 °C comparison (BF 892) 209 s 222 s Product of Example 1 206 s 171 s Product of Example 2 210 s 204 s Product of Example 3 215 s 220 s Optical Appearance Crosslinker forced drying at 180 °C forced drying at 200 °C comparison (BF 892) smooth smoothProduct of Example 1 smooth smooth Product of Example 2 smooth rough Product of Example 3 smooth smooth Solvent Resistance Test (Coil Coated Metals - Test methods Part 11: DIN EN 13523 - 11: 2019- 12; solvent: methylethyl ketone; dry film thickness: see tables supra; Rating: = number of double-rubs without delamination) Crosslinker forced drying at 180 °C forced drying at 200 °C comparison (BF 892) > 50 > 50 Product of Example 1 > 50 > 50 Product of Example 2 > 50 40 Product of Example 3 > 50 > 50 Wedge Bend - Test The test was conducted with the "Bend and Impact Tester, Model 471" of Erichsen GmbH & Co. KG, 58652 Hemer, Germany. Test principle: A bent coated sheet metal panel is subjected to a prescribed impact force thus causing the cylindrical fold in the panel to be squeezed into a conical shape. The test permits to determine the bending radius at which failure of the coating first occurs. Design and function: The Bend and Impact Tester, model 471, consists of 2 vertical tubes which guide a (2300 ± 100) g impact tool with a (650 ± 5) mm drop, and a special-design anvil for placing the test panel. A 5 mm diameter rod mandrel for bending the coated panel is also mounted on the base plate of the instrument. Test procedure: The coated sheet metal panel (50 mm × 140 mm) is bent by 180° over the mandrel with the coating outside. The impact tool is attached to the top between the holding pins and the panel is placed over the anvil with one side touching the stop plate. Then the impact tool is released. Evaluation: A solution is prepared from 100 g of copper sulphate (CuSO4A 5 H2O), 50 g of citricacid, 0.5 ml of sulphuric acid (concentrated, density: 1840 kg / m3) in 1 litre of distilled water.The test panel is submerged in this solution for five minutes, and then rinsed under running water. Any failures in the coating become visible in the form of lines or dots of corrosion. Crosslinker forced drying at 180 °C forced drying at 200 °C panels panels avg 1 2 3 avg 1 2 3 comparison (BF 892) 24 20 25 26 20 16 25 20 Product of Example 1 14 15 14 13 7 0 15 7 Product of Example 2 2 2 2 2 2 2 2 2 Product of Example 3 0 0 0 0 0 0 0 0 In the table, the length of the failure line is indicated in mm, starting from the buckling point (maximum fold). The shorter the line, the better the formative qualities (elasticity, adhesion to the substrate) of the coating. "avg" means: average value of all three panels. Erichsen Cupping Test; according to DIN EN ISO 20482, ("cupping index" in mm as stated in the table is the average of three tests of the depth of indentation when the first crack appears) Crosslinker forced drying at 180 °C forced drying at 200 °C comparison (BF 892) 10.3 9.6 Product of Example 1 10.0 9.3 Product of Example 2 9.6 9.4 Product of Example 3 9.1 8.6 Metal fracture was observed for all samples when the first crack appears Sterilisation Resistance (90 min; 119 °C) - Optical Evaluation Optical appearance of the surface is described infraEvaluation of the effect of sterilisation: Rank Explanation 1 no difference No distinction between test area and surrounding area, no optical differences 2 slight differences Differences between test area and surrounding area; visual in different view angles, e.g. discolouration, changes in gloss; no changes of the surface structure, e.g. swelling, fracture, bubble formation 3 significant differences The test area shows a remarkable difference to the surrounding area. Visual in all view angles, e.g. discolouration, changes of gloss and / or slight changes of the surface structure, e.g. swelling, fracture, bubble formation, but test area is basically undamaged 4 marked differences The surface structure or the colour / gloss has enormously changed or the surface material delaminated in parts or completely; the structure of the testing area has clearly changed. 5 The test area was changed completely or is destroyed Sodium Chloride Solution (mass fraction of solute: 3 %) Crosslinker forced drying at 180 °C forced drying at 200 °C comparison (BF 892) 1 1 Product of Example 1 1 2 Product of Example 2 1 1 Product of Example 3 1 1 Acetic Acid Solution (mass fraction of solute: 3 %) Crosslinker forced drying at 180 °C forced drying at 200 °C comparison (BF 892) 1 2 Product of Example 1 3 3 Product of Example 2 2 2 Product of Example 3 3 3Sterilisation Resistance (90 min; 119 °C) - Adhesion Legend: Adhesion was tested by the Cross-Cut Test according to ISO 2409, with a multi-cut blade, spacing 1 mm; classification of results according to table 1 of the standard: 0 cut edges are completely smooth, none of the squares is detached 1 small flakes of the coating may be detached at the intersections; affected area not more than 5 % 2 coating has flaked along the edges or intersections, affected area is between 5 % and 15 % Sodium Chloride Solution (mass fraction of solute: 3 %) Crosslinker forced drying at 180 °C forced drying at 200 °C comparison (BF 892) 0 0 Product of Example 1 0 0 Product of Example 2 0 0 Product of Example 3 0 0 Acetic Acid Solution (mass fraction of solute: 3 %) Crosslinker forced drying at 180 °C forced drying at 200 °C comparison (BF 892) 0 0 Product of Example 1 0 0 Product of Example 2 0 0 Product of Example 3 0 0 As can be seen by comparison with the reference example using a commercial benzoguanamine-formaldehyde resin, the test values for the samples using the crosslinkers according to the invention are on par with those found for the commercial crosslinker. No formaldehyde was cleaved off the coating samples where the crosslinkers according to the invention were used.Evaluation of the effect of sterilisation: Rank Explanation 1 no difference No distinction between test area and surrounding area, no optical differences 2 slight differences Differences between test area and surrounding area; visual in different view angles, e.g. discolouration, changes in gloss; no changes of the surface structure, e.g. swelling, fracture, bubble formation 3 significant differences The test area shows a remarkable difference to the surrounding area. Visual in all view angles, e.g. discolouration, changes of gloss and / or slight changes of the surface structure, e.g. swelling, fracture, bubble formation, but test area is basically undamaged 4 marked differences The surface structure or the colour / gloss has enormously changed or the surface material delaminated in parts or completely; the structure of the testing area has clearly changed. 5 The test area was changed completely or is destroyed Sodium Chloride Solution (mass fraction of solute: 3 %) Crosslinker forced drying at 180 °C forced drying at 200 °C comparison (BF 892) 1 1 Product of Example 1 1 2 Product of Example 2 1 1 Product of Example 3 1 1 Acetic Acid Solution (mass fraction of solute: 3 %) Crosslinker forced drying at 180 °C forced drying at 200 °C comparison (BF 892) 1 2 Product of Example 1 3 3 Product of Example 2 2 2 Product of Example 3 3 3Sterilisation Resistance (90 min; 119 °C) - Adhesion Legend: Adhesion was tested by the Cross-Cut Test according to ISO 2409, with a multi-cut blade, spacing 1 mm; classification of results according to table 1 of the standard: 0 cut edges are completely smooth, none of the squares is detached 1 small flakes of the coating may be detached at the intersections; affected area not more than 5 % 2 coating has flaked along the edges or intersections, affected area is between 5 % and 15 % Sodium Chloride Solution (mass fraction of solute: 3 %) Crosslinker forced drying at 180 °C forced drying at 200 °C comparison (BF 892) 0 0 Product of Example 1 0 0 Product of Example 2 0 0 Product of Example 3 0 0 Acetic Acid Solution (mass fraction of solute: 3 %) Crosslinker forced drying at 180 °C forced drying at 200 °C comparison (BF 892) 0 0 Product of Example 1 0 0 Product of Example 2 0 0 Product of Example 3 0 0 As can be seen by comparison with the reference example using a commercial benzoguanamine-formaldehyde resin, the test values for the samples using the crosslinkers according to the invention are on par with those found for the commercial crosslinker. No formaldehyde was cleaved off the coating samples where the crosslinkers according to the invention were used.

Claims

223080W0 Claims 1. A crosslinker C obtainable by reaction of - a cyclic organic compound A which is selected from the group consisting of azacyclic organic compounds AN having five (AN5) or six (AN6) atoms in one ring, whereof at least one is a nitrogen atom, and at least two are carbon atoms, having at least two, and up to four, preferably two or three, substituents V bound to different ring atoms which are reactive atoms or functional groups, hereinafter referred to individually as V1, V2, (and, if present V3and, if present V4), which substituents V can be the same, or can be different from each other, and are selected from the group consisting of halogen atoms -F, -Cl, -Br, and from halocarbonyl groups -C(O)- Hal, where -Hal is selected from the group consisting of halogen atoms -F, -Cl, and -Br, - compounds B comprising the following parts: one atom or functional group WBwhich is able to react once with one of V1, V2, (and, if present V3and, if present V4) in a metathesis or condensation reaction; and one at least divalent group G connected to WBwith a chemical bond, wherein the at least divalent group G is selected from the trivalent groups of 1,1,1- alkyltriyls, preferably methanetriyl >C(H)-, 1,1,1-ethanetriyl >C(CH3)-, 1,1,1-propanetriyl >C(CH2-CH3)-, 1,1,1-butanetriyl >C(CH2-CH2-CH3)-, 1,1,1-pentanetriyl >C(CH2-CH2-CH2- CH3)-, 2-oxoalkyl-1,1,1-triyls, preferably 2-oxopropane-1,1,1-triyl >C(CO-CH3)-, cyanomethan- triyl >C(CN)-, and from the divalent groups 2-oxoalkane-1,1-diyls, preferably 2-oxopropane- 1,1-diyl, 2-oxobutane-1,1-diyl, 2-oxopentane-1,1-diyl, and 2,4-dioxopentane-3,3-diyl, and 3- oxobutyronitril-2,2-diyl, and which group G carries at least one, preferably one or two, functional groups Y that can react with functional hydroxyl groups Z of an organic polymer R or of an inorganic material, wherein the group WBof compound B is one hydrogen atom of an acidic methine group CH or acidic methylene group CH2, and wherein the groups Y of compound B are selected from the group consisting of carboxylic acid alkylester groups -C(O)- O-R; acid groups -C(O)-O-H; epoxide groups; aziridine groups; beta-hydroxyalkylamide groups -C(O)-N(H)-CH2-CH2-OH; acid anhydride groups -C(O)-O-(C)-O-Ri; alkylcarbodiimide groups -N=C=N-Rii, cycloalkyl carbodiimide groups -N=C=N-Riii, where any of R, Ri, and Riiare, independently of each other, alkyl groups having from one to six carbon atoms, and Riiiare cycloalkyl groups having from five to eight carbon atoms; groups having a carbon-carbon double bond, optionally activated by electronegative groups, - an at least difunctional compound D which has at least two functional groups WD, individually referred to as WDjwhere j is an integer number being at least two, which groups WDare selected from the group consisting of a hydrogen atom from amino groups -NH2, imino groups -NH-, hydroxyl groups -OH, and thiol groups -SH, with at least one amino group or at least one hydroxyl group being present in compound D, and which can react with one of the substituents V of compound A in a metathesis or condensation reaction, wherein the compound D has the structure Dn(WDj)nwhere Dnstands for a n-valent organic group which has the structural formula X1-E2-X2for n=2, and X1-E3-X3for n=3, where X1, X2, and X3| X2are all divalent groups, selected, independently of each other, from an oxy group or ether group -O-, an imino group -N(H)- or >N(R"), , an amino group, or a sulfide group of thio group -S-, and E2is a divalent linear or branched or cyclic aliphatic group having from two to forty carbon atoms where one or more of phenylene groups -(C6H4)-, methylmethylene groups >C(CH3)-H, ether groups -O-, imino groups -NH-, or alkylimino groups >N–R" may be inserted into the aliphatic chain, where R" may be any alkyl group having at least one carbon atom, and up to twenty carbon atoms, and where none of ether groups-O-, imino groups -NH-, and alkylimino groups >N–R may follow directly in sequence, and wherein E3is a trivalent branched or cyclic aliphatic group having from two to forty carbon atoms where one or more of phenylene groups -(C6H4)-, alkylmethylene groups >C(R)-H, ether groups -O-, imino groups -NH-, or alkylimino groups >N–R' may be inserted into the aliphatic chain, where R and R' may be, independently of each other, any alkyl group having at least one carbon atom, and up to twenty carbon atoms, and where none of ether groups-O-, imino groups -NH-, and alkylimino groups >N–R' may follow directly in sequence, and wherein - the amount of substance of compound B is selected so that the amount of substance n(WB) of functional groups WBof compound B is smaller than the amount of substance n(V) of functional groups V in compound A, and wherein the amount of substance of compound D isselected so that the amount of substance n(WD) of functional groups WDof compound D is equal to, or lower than n(V) - n(WB).

2. The crosslinker C of claim 1 wherein the ratio n(WB) / of the amount of substance n(WB) of functional groups WBof compound B and the amount of substance n(V) of functional groups V in compound A is: 0.1 mol / mol # n(WB) / n(V) # 0.9 mol / mol; preferably 0.2 mol / mol # n(WB) / n(V) # 0.8 mol / mol; and particularly preferred, 0.3 mol / mol# 0.7 mol / mol.

3. The crosslinker C of any one of claim 1 and claim 2 wherein the cyclic organic compound A is selected from the group consisting of - azacyclic organic compound AN5 having one nitrogen atom in a ring, and all other ring atoms are carbon atoms, - azacyclic organic compounds AN5 having two nitrogen atoms in a ring which are preferably located in positions 1 and 2, or in positions 1 and 3, and all other ring atoms are carbon atoms, and - azacyclic organic compounds AN5 having three nitrogen atoms in a ring which are preferably located in positions 1, 2, and 3, or in positions 1, 2, and 4, and all other ring atoms are carbon atoms, and the azacyclic organic compounds AN6 are selected from the group consisting of - azacyclic organic compounds AN6 having one nitrogen atom in a ring, and all other ring atoms are carbon atoms, - azacyclic organic compounds AN6 having two nitrogen atoms in a ring which are preferably located in positions 1 and 2, or 1 and 3, or 1 and 4, and all other ring atoms are carbon atoms, - azacyclic organic compounds AN6 having three nitrogen atoms in a ring which are preferably located in the 1, 3, and 5 positions, and all other ring atoms are carbon atoms, and - azacyclic organic compounds AN6 having four nitrogen atoms in a ring which are preferably located in positions 1, 2, 4, and 5, and all other ring atoms are carbon atoms.

4. The crosslinker C of any one of claims 1, and 2, and 3, wherein the substituents V are the same, or are different from each other, and are selected from the group consisting of -Cl, and chlorocarbonyl groups -C(O)- Cl.

5. The crosslinker C of any one of claims 1, and 2, and 3, and 4, wherein the group WBof compound B is a hydrogen atom of an acidic methine group CH or of an acidic methylene group CH2,activated by neighbouring electronegative groups which are preferably carbonyl, carboxyl, cyano, trifluoromethyl, sulphonyl, or nitro groups.

6. The crosslinker C of any one of claims 1, and 2, and 3, and 4, and 5, wherein the at least divalent group G is selected from the trivalent groups methanetriyl >C(H)-, 1,1,1-ethanetriyl >C(CH3)-, 1,1,1-propanetriyl >C(CH2-CH3)-, 1,1,1-butanetriyl >C(CH2-CH2-CH3)-, 1,1,1- pentanetriyl >C(CH2-CH2-CH2-CH3)-, cyanomethantriyl >C(CN)-, and 2-oxopropane-1,1,1- triyl >C(CO-CH3)-, and from the divalent groups 2-oxopropane-1,1-diyl, 2-oxobutane-1,1-diyl, 2-oxopentane-1,1-diyl, 2,4-dioxopentane-3,3-diyl, and 3-oxobutyronitril-2,2-diyl.

7. The crosslinker C of one of claims 1, and 2, and 3, and 4, and 5, and 6, wherein the groups Y of compounds B are preferably selected from the group consisting of carboxylic acid alkylester groups C(O)-O-Alk, where Alk- is the alkyl group of the alkylester and is selected from the group consisting of methyl, ethyl, isopropyl, n-propyl, n-butyl, sec-butyl, iso-butyl and tert-butyl groups.

8. The crosslinkers C of any one of claims 1, and 2, and 3, and 4, and 5, and 6, and 7, wherein the groups WDof compound D are, independently of each other, a hydrogen atom from the group consisting of hydroxyl groups -OH, and amino groups -NH2.

9. The crosslinkers C of any one of claims 1, and 2, and 3, and 4, and 5, and 6, and 7, and 8, wherein the cyclic organic compound A is trichlorocyanuric acid (cyanuric trichloride or 2,4,6-trichloro-1,3,5-triazine), the compound B is selected from the group consisting of diethylmalonate, diethyl-2-methylmalonate, diethyl-2-ethylmalonate, diethyl-2-hydroxymalonate, diethyl-3-hydroxyglutarate, and the corresponding dimethyl esters, and the compound D is selected from the group consisting of 1,2-dihydroxyethane (ethylene glycol), 1,2- dihydroxypropane, 1,3-dihydroxypropane, 1,4-diyhdroxybutane, 1,6-dihydroxyhexane, oligomeric or polymeric ethylene glycols or propylene glycols, or copolymers thereof, 1,2- diaminoethane, 1,4-diaminobutane, 1,6-diaminohexane, isophoronediamine (IPDA, 3- aminomethyl-3,5,5-trimethylcyclohexane-1-amine), meta-xylylenediamine (MXDA, 1,1'-(1,3- phenylene)di(methanamine)), oligomeric and polymeric 2-aminopropoxy-(propoxy)i-propane- 2-amines where i can assume integer values from 1 to 80, and where propoxy and propane may also be replaced by ethoxy and ethane groups, and 2-(2-aminoethoxy)ethanol, and mixtures of these.

10. A process for preparing the crosslinker C of any one of claims 1, and 2, and 3, and 4, and 5, and 6, and 7, and 8, and 9, wherein - in a first step, a cyclic organic compound A as defined in claim 1 is reacted with compounds B as defined in claim 1 under formation of an intermediate product I, wherein - the amount of substance of compound B is selected so that the amount of substance n(WB) of functional groups WBof compound B is smaller than the amount of substance n(V) of functional groups V in compound A, and wherein the reaction is - a condensation reaction under formation of a condensate VWBand formation of a chemical bond between the atoms of A and B that were carrying the groups V and WB, and - wherein, in a second step, the product I of the first reaction step is reacted with an at least difunctional compound D as defined in claim 1 which has at least two functional groups WDjwhere j is an integer number and at least two, which groups WDjcan react with one of the substituents V in an addition or condensation reaction to form the crosslinker C, wherein the amount of substance of compound D is selected so that the amount of substance n(WD) of functional groups WDof compound D is equal to, or greater than n(V) - n(WB).

11. The process of claim 10 wherein the ratio n(WB) / n(V) of the amount of substancen(WB) of functional groups WBof compound B and the amount of substance n(V) of functional groups V in compound A is: 0.5 mol / mol # n(WB) / n(V) # 0.9 mol / mol; preferably 0.60.8 mol / mol; and particularly preferred, 0.65 mol / mol# 0.75 mol / mol.

12. The crosslinker of any one of claims 1, and 2, and 3, and 4, and 5, and 6, and 7, and 8, and 9, wherein at least a part of the compound D is replaced by a monofunctional compound M having the structure WM- M’, where WMis the hydrogen atom of groups selected from the group consisting of a hydroxyl group -OH, a thiol group -SH, an amino group -NH2, and an imino group >N-H, and where -M’ is -X4-E4, where X4 are divalent groups, selected from an oxy group or ether group -O-, an imino group -N(H)- or >N(R"'), an amino group, or a sulfide group of thio group -S-, and E4is a monovalent linear or branched or cyclic aliphatic group having from two to forty carbon atoms where one or more of phenylene groups -(C6H4)-, methylmethylene groups >C(CH3)-H, ether groups -O-, imino groups -NH-, or alkylimino groups >N–R"' may be inserted into the aliphatic chain, where R"' and Rivmay, independent from each other, be any alkyl group having at least one carbon atom, and up to twenty carbon atoms, and where none of ether groups-O-, imino groups -NH-, and alkylimino groups >N–Rivmay follow directly in sequence wherein the amount of M is chosen such that the amount of substance of functional groups WMis at least 0.1 × ( n(V) - n(WB) ), and not more than 0.9 × ( n(V)- n(WB) ).

13. A process for preparing the crosslinker C of one of claims 1, and 2, and 3, and 4, and 5, and 6, and 7, and 8, and 9, and 12, wherein - in a first step, a cyclic organic compound A as defined hereinbefore is reacted with - compounds D as defined hereinbefore under formation of an intermediate product I2, wherein - the amount of substance of compound D is selected so that the amount of substance n(WD) of functional groups WDof compound D is smaller than the amount of substance n(V) of functional groups V in compound A, and wherein the reaction is- a condensation reaction under formation of a condensate VWDand formation of a chemical bond between the atoms of A and D that were carrying the groups V and WD, and - wherein, in a second step, the product I2 of the first reaction step is reacted with a compound B as defined hereinbefore to form the crosslinker C, wherein the amount of substance of compound B is selected so that the amount of substance n(WB) of functional groups WBof compound B is at least equal to n(V) - n(WD).

14. The process of claim 13, wherein at least a part of the compound D is replaced by a monofunctional compound M having the structure WM- M’, where M’ is selected from alkyl groups having from one to twenty carbon atoms, and WMis selected from the group consisting of hydroxyl groups -OH, amino groups -NH2, imino groups >NH, and thiol groups -SH, and wherein the amount of M is chosen such that the amount of substance of functional groups WMis at least 0.1 × ( n(V) - n(WB) ), and not more than 0.9 × ( n(V) - n(WB) ).

15. A process for preparing the crosslinker C of one of claims 1, and 2, and 3, and 4, and 5, and 6, and 7, and 8, and 8, and 9, and 12, wherein - in a first step, a cyclic organic compound A as defined in claim 1 is reacted with - compounds D as defined in claim 1, wherein at least a part of the compound D may be replaced by a monofunctional compound M having the structure WM- M’, where M’ is selected from alkyl groups having from one to twenty carbon atoms, and WMis selected from the group consisting of hydroxyl groups -OH, amino groups -NH2, imino groups >NH, and thiol groups -SH, under formation of an intermediate product I3, - wherein the amount of substance of compounds D and M is selected so that the sum n(WD) + n(WM) of the amount of substance n(WD) of functional groups WDof compound D and the amount of substance n(WM) of functional groups WMof compound M is smaller than the amount of substance n(V) of functional groups V in compound A, and wherein the reaction is a condensation reaction under formation of condensate VWDand VWMand formation of a chemical bond between the atoms of A and one or more of D and M that were carrying the groups V and WD, and / or WM, and- in a second step, the product I3 of the first reaction step is reacted with a compound B as defined in claim 1, wherein the amount of substance of compound B is selected so that the amount of substance n(WB) of functional groups WBof compound B is less than the remaining amount of substance n(V) of functional groups V in the product I3 of the first reaction step, to form an intermediate product I4, and - in a third step, the intermediate product I4 is reacted with a further portion of a compound D, wherein at least a part of the compound D may be replaced by the said monofunctional compound M, to form a crosslinker C, wherein the amount of substance of compounds D and / or M is selected so that the sum n(WD) + n(WM) of the amount of substance n(WD) of functional groups WDof compound D and the amount of substance n(WM) of functional groups WMof compound M is equal to, or up to 50 % higher than, the remaining amount of substance n(V) of functional groups V in the product I4 of the second reaction step.

16. A method of use of the crosslinker C of one of claims 1, and 2, and 3, and 4, and 5, and 6, and 7, and 8, and 9, and 10, and 13, or made by the process of one of claims 10, and 11, and 13, and 14, and 15, together with - organic polymers which are selected from the group consisting of binder resins for coating compositions, elastomeric materials, organic natural or synthetic fibres, textiles made therefrom, nonwoven materials such as felts, spunbond, or paper, cardboard based on synthetic or natural organic polymers, where the crosslinkers react with functional groups present in the organic polymer to improve the physical, mechanical or chemical properties , or modify surface or adhesion properties, and / or - inorganic materials such as glass, ceramics, stone, concrete, which have hydroxyl groups, or acid or basic sites on their surface or within pores which react with the crosslinkers C under modification of external and internal surfaces, which method comprises mixing the crosslinker C with one or more of the said organic polymers and / or inorganic materials, and wherein the functional groups Z of the said organic polymers are selected from the group consisting of hydroxy groups, amino groups, imino groups, and thiol groups.

17. The method of use of claim 16 wherein the crosslinker C is used together with an organic polymer R by mixing the crosslinker C with the organic polymer R to obtain a coating composition or a moulding composition.

18. The method of use of claim 17 comprising applying the coating composition, optionally in the presence of a catalyst, to a surface of textiles, nonwoven materials such as felts, spunbond, paper, or cardboard based on synthetic or natural organic polymers, inorganic materials such as glass, ceramics, stone, concrete, or coated metal sheets which have hydroxyl groups, or acid or basic sites on their surface or within pores, followed by a drying step at room temperature (25 °C) or elevated temperature, or impregnating porous material with the said mixture, also followed by a drying step.

19. The method of use of claim 17 wherein the crosslinker C is separately mixed and compounded with an elastomeric material, and this compound is added during the compounding process of rubber compounds.

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