Two-component coating system

Abstract

The present invention relates to a two-component coating system, the two-component coating system comprising a first component and a second component, each of the first component and the second component being separate and different from each other, wherein the first component comprises a carboxylic acid-functional polymer dissolved and / or dispersed in an aqueous medium, and the second component comprises a polyaziridine compound having: a) 2 to 6 of the following structural units (A): wherein m is an integer from 1 to 8; and both R' and R” are H; b) one or more linking chains, each of these linking chains linking two of the structural units A; c) one or more linking groups, each of the linking groups linking two of the structural units A; and d) a molecular weight in the range from 840 daltons to 5000 daltons, wherein the molecular weight is measured using MALDI-TOF mass spectrometry.

Description

[0001] The present invention relates to a two-component coating system, which comprises a first component and a second component, each of the first component and the second component being separate and different from each other, wherein the first component comprises a carboxylic acid-functional polymer dissolved and / or dispersed in an aqueous medium, and the second component comprises a polyaziridine compound, wherein the first component and the second component are stored separately because the crosslinking reaction between the crosslinking agent and the polymer to be crosslinked can start immediately after mixing the aqueous composition of the crosslinking agent and the polymer to be crosslinked.

[0002] For many years, there has been an increasing demand for coatings with improved resistance properties such as stain resistance and solvent resistance, improved mechanical properties and improved adhesion strength. One or more of these properties can be enhanced to a higher level by means of crosslinking. Many crosslinking mechanisms have been developed over the years, and for aqueous dispersions, the most useful crosslinking mechanisms include isocyanate crosslinking of hydroxy-functional dispersions, the reaction between carbodiimide and carboxylic acid, epoxy crosslinking, and crosslinking using aziridine-based crosslinking agents.

[0003] US-A-5133997 describes a coating composition comprising an aqueous dispersion of a linear aliphatic polyurethane resin, an anionic surfactant, and a crosslinking agent capable of promoting the curing of the resin. Trimethylolpropane tris(2-methyl-1-aziridinepropionate), CAS number 64265-57-2, a polyfunctional aziridine crosslinking agent, is used as the crosslinking agent, which is well known and highly active for crosslinking carboxylic acid-functional polymers. However, this crosslinking agent has an adverse genotoxic profile. There is a need in the industry to improve the safety, health and environmental profiles of adhesives, inks and coatings, and the substances used in the preparation of adhesives, inks and coatings. Genotoxicity describes the property of a chemical or physical agent that causes any type of DNA damage, which may not always result in transmissible mutations. Mutagenicity refers to the induction of permanent transmissible DNA changes (either as DNA composition or chromosomal structure), which are maintained during somatic cell division and passed on to progeny in germ cells. Genotoxicity should not be confused with mutagenicity. All mutagens are genotoxic, while not all genotoxic substances are mutagenic.

[0004] The object of the present invention is to provide a two-component coating system, which comprises a first component and a second component, each of the first component and the second component being separate and different from each other, wherein the first component comprises a carboxylic acid-functional polymer dissolved and / or dispersed in an aqueous medium, and the second component comprises a compound having at least two aziridinyl groups, which compound has reduced genotoxicity compared to trimethylolpropane tris(2-methyl-1-aziridinepropionate) and has good crosslinking efficiency. The compound having at least two aziridinyl groups is also referred to herein as a polyaziridine compound.

[0005] This object has surprisingly been achieved by providing a two-component coating system, which comprises a first component and a second component, each of the first component and the second component being separate and different from each other, wherein

[0006] the first component comprises a carboxylic acid-functional polymer dissolved and / or, preferably, dispersed in an aqueous medium, and

[0007] the second component comprises a polyaziridine compound having:

[0008] a) 2 to 6 of the following structural units (A):

[0009]

[0010] wherein

[0011] m is an integer from 1 to 6, and

[0012] both R' and R” are H;

[0013] b) one or more linking chains, each of which linking two of the structural units A;

[0014] c) one or more linking groups, each of which linking two of the structural units A, and wherein the linking group preferably consists of at least one functional group selected from: aliphatic hydrocarbon functional group, cycloaliphatic hydrocarbon functional group, aromatic hydrocarbon functional group, isocyanurate functional group, iminodioxazine dione functional group, ether functional group, ester functional group, amide functional group, carbonate functional group, carbamate functional group, urea functional group, biuret functional group, urethane functional group, uretidione functional group, and any combination thereof; and

[0015] d) a molecular weight in the range from 840 daltons to 5000 daltons.

[0016] It has surprisingly been found that these polyaziridine compounds have reduced genotoxicity compared to trimethylolpropane tris(2-methyl-1-aziridinepropionate). The polyaziridine compounds according to the invention show only weakly positive induced genotoxicity, or even they do not show genotoxicity, i.e., they show a genotoxicity level comparable to the naturally occurring background.

[0017] Genotoxicity can be measured by the assay (Toxys, Leiden, the Netherlands) as further described herein. The assay can be applied to pure substances or to compositions which are the direct products obtained in the preparation of the polyaziridine compounds according to the invention. Positive induced genotoxicity means that the induction levels of the biomarkers Bscl2-GFP and Rtkn-GFP are equal to or higher than 2-fold at at least one of 10%, 25% and 50% cytotoxicity in the absence or presence of the metabolic system rat S9 liver extract. Weakly positive induced genotoxicity means that the induction levels of the biomarkers Bscl2-GFP and Rtkn-GFP are higher than 1.5-fold and lower than 2-fold (but lower than 2-fold at 10%, 25% and 50% cytotoxicity) at at least one of 10%, 25% and 50% cytotoxicity in the absence or presence of the metabolic system based on rat S9 liver extract (aroclor 1254-induced rats, Moltox, Boone, NC, USA). Genotoxicity comparable to the naturally occurring background means that the induction levels of the biomarkers Bscl2-GFP and Rtkn-GFP are less than or equal to 1.5-fold at 10%, 25% and 50% cytotoxicity in the absence and presence of the metabolic system based on rat S9 liver extract (aroclor 1254-induced rats, Moltox, Boone, NC, USA). Preferably, the induction levels of the genotoxicity reporter genes Bscl2-GFP and Rtkn-GFP are less than or equal to 1.5-fold at 10%, 25% and 50% cytotoxicity in the absence and presence of the metabolic system based on rat S9 liver extract (aroclor 1254-induced rats, Moltox, Boone, NC, USA). Substances showing induction levels less than or equal to 1.5-fold at 10%, 25% and 50% cytotoxicity in the absence and presence of the metabolic system based on rat S9 liver extract (aroclor 1254-induced rats, Moltox, Boone, NC, USA) are not genotoxic.

[0018] US-A-3523750 describes a method for modifying protein substrates such as wool with polyaziridine compounds. US-A-5258481 describes multifunctional water-dispersible crosslinking agents which are oligomeric materials containing carbodiimide functional groups and reactive functional groups different from the carbodiimide functional groups. US-A-5359005 describes one-pack coating compositions which comprise at least one polymer and / or oligomer having a molecular weight of at least about 100 and bearing at least two aziridine moieties, at least two carbodiimide moieties, or a combination thereof; and at least one polymer and / or oligomer bearing at least two covalently blocked carboxylic acid moieties.

[0019] For all upper and / or lower boundaries of any range given herein, unless specifically indicated otherwise, the boundary values are included within the given range. Thus, when it is said from x to y, it means including x and y as well as all intermediate values.

[0020] In this specification, the term "coating composition" encompasses paints, coatings, varnishes, adhesive and ink compositions, but is not limited to this list. The term "aliphatic hydrocarbon group" means an optionally branched alkyl, alkenyl and alkynyl group. The term "alicyclic hydrocarbon group" means a cycloalkyl and cycloalkenyl group optionally substituted with at least one aliphatic hydrocarbon group. The term "aromatic hydrocarbon group" means a benzene ring optionally substituted with at least one aliphatic hydrocarbon group. These optional aliphatic hydrocarbon group substituents are preferably alkyl groups. Examples of alicyclic hydrocarbon groups having 7 carbon atoms are cycloheptyl and methyl-substituted cyclohexyl. Examples of aromatic hydrocarbon groups having 7 carbon atoms are methyl-substituted phenyl. Examples of aromatic hydrocarbon groups having 8 carbon atoms are xylenyl and ethyl-substituted phenyl.

[0021] The crosslinking efficiency of the crosslinking agent can be evaluated by assessing the chemical resistance defined and determined as described below.

[0022] Although the structural units (A) in the polyaziridine compound present in the second component of the two-component coating system can independently have different m, R' and / or R", the structural units (A) present in the polyaziridine compound are preferably identical to each other.

[0023] The polyaziridine compound present in the second component of the two-component coating system is usually obtained in the form of a composition in which, in addition to the polyaziridine compound, there may also be present remaining starting materials, by-products and / or solvents used in the preparation of the polyaziridine compound. The composition may contain only one polyaziridine compound as defined in the present invention, but may also contain more than one polyaziridine compound as defined in the present invention. For example, when a mixture of polyisocyanates is used as the starting material, a mixture of polyaziridine compounds is obtained.

[0024] The urethane aziridine compound present in the second component of the two-component coating system contains 2 to 6 structural units (A), preferably 2 to 4 structural units (A), more preferably 2 or 3 structural units (A). m is an integer from 1 to 6, preferably m is from 1 to 4, more preferably m is 1 or 2, and most preferably m is 1.

[0025] The molecular weight of the polyaziridine compound present in the second component of the two-component coating system is from 840 to 5000 daltons. The molecular weight of the polyaziridine compound present in the second component of the two-component coating system is preferably at most 3800 daltons, more preferably at most 3600 daltons, more preferably at most 3000 daltons, more preferably at most 1600 daltons, and even more preferably at most 1200 daltons. The molecular weight of the polyaziridine compound present in the second component of the two-component coating system is preferably at least 890 daltons, more preferably at least 940 daltons, and most preferably at least 1000 daltons. As used herein, the molecular weight of the polyaziridine compound is the calculated molecular weight. The calculated molecular weight is obtained by adding the atomic masses of all the atoms present in the structural formula of the polyaziridine compound. If the polyaziridine compound is present in a composition containing more than one polyaziridine compound according to the present invention, for example when one or more of the starting materials used to prepare the polyaziridine compound are mixtures, then the molecular weight calculation can be performed for each compound present individually in the composition. The molecular weight of the polyaziridine compound present in the second component of the two-component coating system can be measured using MALDI-TOF mass spectrometry as described in the following experimental section.

[0026] The polyaziridine compound present in the second component of the two-component coating system contains one or more linking chains, where each of these linking chains links two in structural unit A. The linking chains present in the polyaziridine compound preferably consist of 4 to 300 atoms, more preferably 5 to 250 atoms, more preferably 6 to 100 atoms, and most preferably 6 to 20 atoms. The atoms of the linking chain are preferably C and optionally N, O, S, and / or P, preferably C and optionally N and / or O. The linking chain is preferably a collection of covalently linked atoms consisting of i) carbon atoms, ii) carbon and nitrogen atoms, or iii) carbon, oxygen, and nitrogen atoms.

[0027] The linking chain is defined as the shortest continuous chain of atoms that links two structural units A. The following figure shows the linking chain between two structural units A of an example of a polyaziridine compound according to the present invention.

[0028]

[0029] Any two of the structural units A present in the polyaziridine compound present in the second component of the two-component coating system are linked via a linking chain as defined herein. Thus, each structural unit A present in the polyaziridine compound present in the second component of the two-component coating system is linked to each other structural unit A via a linking chain as defined herein. In the case where the polyaziridine compound present in the second component of the two-component coating system has two structural units A, the polyaziridine compound has one such linking chain linking the two structural units. In the case where the polyaziridine compound present in the second component of the two-component coating system has three structural units A, the polyaziridine compound has three linking chains, where each of the three linking chains links a structural unit A to another structural unit A, i.e., the first structural unit A is linked to the second structural unit A via a linking chain, and both the first and second structural units A are independently linked to the third structural unit A via their respective linking chains.

[0030] The following drawings illustrate, for an example of a polyaziridine compound having three structural units A, three linking chains, where each of the three linking chains links two structural units A.

[0031]

[0032] A polyaziridine compound having more than two structural units A present in the second component of the two-component coating system has a number of linking chains according to the following equation:

[0033] LC = {(AN - 1)×AN)} / 2, where LC = the number of linking chains in the polyaziridine compound, and AN = the number of structural units A in the polyaziridine compound. Thus, for example, if there are 5 structural units A in the polyaziridine compound, then AN = 5; this means there are {(5 - 1)×5} / 2 = 10 linking chains.

[0034] Preferably, the number of consecutive C atoms and optional O atoms between the N atom of the carbamate group in structural unit A and the next N atom (which is present in the linking chain or is the N atom of the carbamate group of another structural unit A) is at most 9, as shown, for example, in the following polyaziridine compounds according to the invention.

[0035]

[0036] The polyaziridine compound present in the second component of the two-component coating system contains one or more linking groups, where each of these linking groups links two in structural unit A, and the linking group preferably consists of at least one functional group selected from the group consisting of: aliphatic hydrocarbon functional groups (preferably containing 1 to 8 carbon atoms), alicyclic hydrocarbon functional groups (preferably containing 4 to 10 carbon atoms), aromatic hydrocarbon functional groups (preferably containing 6 to 12 carbon atoms), isocyanurate functional groups, iminooxadiazinedione functional groups, ether functional groups, ester functional groups, amide functional groups, carbonate functional groups, urethane functional groups, urea functional groups, biuret functional groups, urethane functional groups, uredione functional groups, and any combination thereof. More preferably, the linking group is an array of contiguous functional groups, where each functional group is selected from the group consisting of: aliphatic hydrocarbon functional groups (preferably containing 1 to 8 carbon atoms), alicyclic hydrocarbon functional groups (preferably containing 4 to 10 carbon atoms), aromatic hydrocarbon functional groups (preferably containing 6 to 12 carbon atoms), isocyanurate functional groups, iminooxadiazinedione functional groups, ether functional groups, ester functional groups, amide functional groups, carbonate functional groups, urethane functional groups, urea functional groups, biuret functional groups, urethane functional groups, or uredione functional groups.

[0037] The following figure shows in bold the linking groups for the following examples of polyaziridine compounds present in the second component of the two-component coating system. In this example, the linking group linking two structural units A consists of the following array of contiguous functional groups: alicyclic hydrocarbon functional group 1 (cyclic C 9 H 16 ), aliphatic hydrocarbon functional group 2 (CH 2 ), isocyanurate 3 (cyclic C 3 N 3 O 3 ), aliphatic hydrocarbon functional group 4 (CH 2 ), and alicyclic hydrocarbon functional group 5 (cyclic C 9 H 16 ) and.

[0038]

[0039] Any two of the structural units A present in the polyaziridine compound present in the second component of the two-component coating system are preferably linked via a linking group as defined herein. Thus, each structural unit A present in the polyaziridine compound present in the second component of the two-component coating system is preferably linked to each other structural unit A using a linking group as defined in the present invention. In the case where the polyaziridine compound according to the present invention has two structural units A, the polyaziridine compound has one such linking group linking the two structural units. In the case where the polyaziridine compound according to the present invention has three structural units A, the polyaziridine compound has three such linking groups, each of the three linking groups linking a structural unit A to another structural unit A.

[0040] Preferably, the linking group consists of at least one functional group selected from the group consisting of: aliphatic hydrocarbon functional groups (preferably containing 1 to 8 carbon atoms), cycloaliphatic hydrocarbon functional groups (preferably containing 4 to 10 carbon atoms), aromatic hydrocarbon functional groups (preferably containing 6 to 12 carbon atoms), isocyanurate functional groups, iminooxadiazinedione functional groups, urethane functional groups, urea functional groups, biuret functional groups, and any combination thereof. The linking group preferably contains an isocyanurate functional group, an iminooxadiazinedione functional group, a biuret functional group, a urethane functional group or a uretdione functional group. More preferably, the linking group contains an isocyanurate functional group or an iminooxadiazinedione functional group. For clarity, the polyaziridine compound can be obtained from the reaction product of one or more suitable compounds B with a hybrid isocyanurate (such as an HDI / IPDI isocyanurate), thereby producing a polyaziridine compound having a linking group consisting of an array of the following consecutive functional groups: straight-chain C 6 H 12 (i.e., an aliphatic hydrocarbon functional group having 6 carbon atoms), an isocyanurate functional group (cyclic C 3 N 3 O 3 ) and

[0041]

[0042] (i.e., a cycloaliphatic hydrocarbon functional group having 9 carbon atoms and an aliphatic hydrocarbon functional group having 1 carbon atom).

[0043] The term "aliphatic hydrocarbon functional group" refers to optionally branched alkyl, alkenyl, and alkynyl groups. Although any optional side chains of C atoms are part of the linking group, they are not part of the linking chain. The term "alicyclic hydrocarbon functional group" refers to cycloalkyl and cycloalkenyl groups optionally substituted by at least one aliphatic hydrocarbon group. Although any optional aliphatic hydrocarbon group substituents are part of the linking group, they are not part of the linking chain. The optional aliphatic hydrocarbon group substituents are preferably alkyl groups. The term "aromatic hydrocarbon functional group" refers to a benzene ring optionally substituted by at least one aliphatic hydrocarbon group. The optional aliphatic hydrocarbon group substituents are preferably alkyl groups. Although any optional aliphatic hydrocarbon group substituents are part of the linking group, they are not part of the linking chain.

[0044] On the linking group, one or more substituents may be present as side groups on the linking group, as shown in bold in the following polyaziridine compounds, for example. These side groups are not part of the linking group.

[0045]

[0046] The side groups preferably contain wherein X, R 7 , R 8 , n', and R 10 are as described below. In one embodiment of the invention, the polyaziridine compound comprises one or more linking groups, wherein each of these linking groups links two in structural unit A, and wherein the linking group consists of: (i) at least two aliphatic hydrocarbon functional groups or at least two alicyclic hydrocarbon functional groups, and (ii) an isocyanurate functional group or an iminooxadiazinedione functional group, and wherein side groups are present on the linking group, and wherein the side groups have the following structural formula:

[0047]

[0048] n' is the number of repeating units and is an integer from 1 to 50, preferably 2 to 30, more preferably 5 to 20.

[0049] X is O or NH, preferably X is O,

[0050] In each repeating unit, R 7 and R 8 are independently H or CH 3 ,

[0051] R 9 is an aliphatic hydrocarbon group preferably containing 1 to 8 carbon atoms, or an alicyclic hydrocarbon group preferably containing 4 to 10 carbon atoms, and

[0052] R 10contains at most 20 carbon atoms and is an aliphatic, cycloaliphatic or aromatic hydrocarbon group, or a combination thereof. In a preferred embodiment, R 7 and R 8 one of which is H and the other R 7 or R 8 is CH 3 . In another more preferred embodiment, R 7 and R 8 are H. R 10 is preferably an aliphatic hydrocarbon group containing 1 to 20 carbon atoms (preferably CH 3 ), a cycloaliphatic hydrocarbon group containing 5 to 20 carbon atoms, or an aromatic hydrocarbon group containing 6 to 20 carbon atoms. The presence of the side group results in a decrease in the viscosity of the polyaziridine compound and thus easier miscibility with the polymer to be crosslinked. In this embodiment, the polyaziridine compound preferably contains 2 structural units A. In this embodiment, the linking group preferably consists of an array of the following consecutive functional groups: a first cycloaliphatic hydrocarbon functional group, an isocyanurate functional group or an iminodioxazine dione functional group, and a second cycloaliphatic hydrocarbon functional group, and R 9 is a cycloaliphatic hydrocarbon group, wherein the first cycloaliphatic hydrocarbon functional group and the second cycloaliphatic hydrocarbon functional group are the same as R 9 . More preferably, the linking group consists of an array of the following consecutive functional groups: a first aliphatic hydrocarbon functional group, an isocyanurate functional group or an iminodioxazine dione functional group and a second aliphatic hydrocarbon functional group, and R 9 is an aliphatic hydrocarbon functional group, wherein the first aliphatic hydrocarbon functional group and the second aliphatic hydrocarbon functional group are the same as R 9 .

[0053] In a preferred embodiment, the polyaziridine compound according to the present invention contains polyoxyethylene (-O-CH2-CH2-) x groups and / or polyoxypropylene (-O-CHCH3-CH2-) x groups in an amount preferably of at least 0.1 wt%, more preferably at least 6 wt%, more preferably at least 10 wt% and preferably less than 45 wt%, more preferably less than 25 wt%, most preferably less than 16 wt% based on the polyaziridine compound. Preferably, the polyaziridine compound contains polyoxyethylene (-O-CH2-CH2-) x groups in an amount preferably of at least 0.1 wt%, more preferably at least 6 wt%, more preferably at least 10 wt% and preferably less than 45 wt%, more preferably less than 45 wt% and most preferably less than 16 wt% based on the polyaziridine compound. Containing polyoxyethylene (-O-CH2-CH2-) xThe polyaziridine compound of the group is preferably at least the reaction product of compound (B), a polyisocyanate, and an alkoxypoly(ethylene glycol) (preferably methoxypoly(ethylene glycol) (MPEG)) and / or poly(ethylene glycol). The reaction product can be obtained by reacting at least compound B, a polyisocyanate, and an alkoxypoly(ethylene glycol) and / or poly(ethylene glycol), and compound B has the following structural formula

[0054]

[0055] wherein R' and R” are as defined above. The reaction product can also be obtained by reacting a polyisocyanate with an alkoxypoly(ethylene glycol) and / or poly(ethylene glycol) and reacting the compound thus obtained with compound (B). The reaction product can also be obtained by reacting compound (B) with a polyisocyanate and reacting the compound thus obtained with an alkoxypoly(ethylene glycol) and / or poly(ethylene glycol). In the polyaziridine compound as defined above, the number average molecular weight M n is higher than 2200 daltons, preferably M n The amount of the alkoxypoly(ethylene glycol) (preferably methoxypoly(ethylene glycol) (MPEG)) and / or poly(ethylene glycol) (PEG) chain with a molecular weight higher than 1600 daltons is preferably less than 35% by weight, more preferably less than 15% by weight, still more preferably less than 5% by weight, and most preferably 0% by weight. The M of the methoxypoly(ethylene glycol) (MPEG) and / or poly(ethylene glycol) (PEG) chain present in the polyaziridine compound n is preferably lower than 1100 daltons, more preferably lower than 770 daltons, and most preferably lower than 570 daltons.

[0056] The isocyanurate functional group is defined as

[0057] The iminooxadiazinedione functional group is defined as

[0058] The urethane functional group is defined as

[0059] The uretdione functional group is defined as

[0060] The biuret functional group is defined as

[0061] In a preferred embodiment of the present invention, the linking group present in the polyaziridine compound present in the second component of the two-component coating system consists of the following functional groups: (i) at least one aliphatic hydrocarbon functional group and / or at least one cycloaliphatic hydrocarbon functional group; (ii) and an isocyanurate functional group or an iminodioxazine dione functional group or a urethane functional group or a uretidione functional group; and (iii) optionally at least one aromatic hydrocarbon functional group. Preferably, the linking group present in the polyaziridine compound present in the second component of the two-component coating system consists of the following functional groups: (i) at least one aliphatic hydrocarbon functional group and / or at least one cycloaliphatic hydrocarbon functional group; and (ii) an isocyanurate functional group or an iminodioxazine dione functional group; and (iii) optionally at least one aromatic hydrocarbon functional group. A very suitable way to obtain such polyaziridine compounds is to react a compound B having the following structural formula with a polyisocyanate having aliphatic reactivity:

[0062]

[0063] The term "aliphatic-reactive polyisocyanate" refers to a compound in which all isocyanate groups are directly bonded to an aliphatic or cycloaliphatic hydrocarbon group, regardless of whether an aromatic hydrocarbon group is also present. The aliphatic-reactive polyisocyanate can be a mixture of aliphatic-reactive polyisocyanates. When compared to similar compounds based on aromatic-reactive polyisocyanates, compounds based on aliphatic-reactive polyisocyanates have a reduced tendency to yellow over time. The term "aromatic-reactive polyisocyanate" is intended to mean a compound in which all isocyanate groups are directly bonded to a benzene or naphthalene group, regardless of whether an aliphatic or cycloaliphatic group is also present. Preferred aliphatic-reactive polyisocyanates are 1,5-pentamethylene diisocyanate PDI, 1,6-hexamethylene diisocyanate HDI, isophorone diisocyanate IPDI, 4,4'-dicyclohexylmethane diisocyanate H12MDI, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, tetramethylxylene diisocyanate TMXDI (all isomers) and higher molecular weight variants such as, for example, their isocyanurates or iminooxadiazinediones. More preferred aliphatic-reactive polyisocyanates are the isocyanurates or iminooxadiazinediones of 1,5-pentamethylene diisocyanate PDI, 1,6-hexamethylene diisocyanate HDI, isophorone diisocyanate IPDI, 4,4'-dicyclohexylmethane diisocyanate H12MDI, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, tetramethylxylene diisocyanate TMXDI. In this embodiment, preferably, the linking group consists of an array of the following consecutive functional groups: an aliphatic hydrocarbon functional group, an aromatic hydrocarbon functional group, and an aliphatic hydrocarbon functional group (for example, when preparing a polyaziridine compound using TMXDI), or the linking group consists of an array of the following consecutive functional groups: a cycloaliphatic hydrocarbon functional group, an aliphatic hydrocarbon functional group, and a cycloaliphatic hydrocarbon functional group (for example, when preparing a polyaziridine compound using H12MDI), or more preferably, the linking group consists of an array of the following consecutive functional groups: an aliphatic hydrocarbon functional group, an isocyanurate functional group or an iminooxadiazinedione functional group, and an aliphatic hydrocarbon functional group. Most preferably, in this embodiment, the linking group consists of an array of the following consecutive functional groups: an aliphatic hydrocarbon functional group, an isocyanurate functional group, and an aliphatic hydrocarbon functional group (for example, when preparing a polyaziridine compound using the isocyanurate of 1,6-hexamethylene diisocyanate and / or the isocyanurate of 1,5-pentamethylene diisocyanate).

[0064] The polyaziridine compound present in the second component of the two-component coating system preferably contains at least 5% by weight, more preferably at least 5.5% by weight, more preferably at least 6% by weight, more preferably at least 9% by weight, more preferably at least 12% by weight and preferably less than 25% by weight, preferably less than 20% by weight of urethane bonds. The aziridine equivalent weight of the polyaziridine compound present in the second component of the two-component coating system (the molecular weight of the polyaziridine compound divided by the number of aziridine groups present in the polyaziridine compound) is preferably at least 200 daltons, more preferably at least 230 daltons and even more preferably at least 260 daltons, and preferably at most 2500 daltons, more preferably at most 1000 daltons and even more preferably at most 500 daltons.

[0065] If desired, the polyaziridine compound can be stabilized with an amine, preferably 0.1% to 5% by weight, more preferably 0.1% to 2.5% by weight, most preferably 0.1% to 1% by weight of a secondary or tertiary amine. Preferred amines include ammonia, dimethylethanolamine, diisopropylamine, isopropanolamine, diethylethanolamine, N,N-dimethylisopropanolamine, 3-dimethylamino-1-propanol, 2-[2-(dimethylamino)ethoxy]ethanol, N-ethy morpholine and dimethylbenzylamine triethylamine. Alternatively, an alkaline hydroxide such as, for example, NaOH, LiOH, KOH and combinations of amines with alkaline hydroxides can be used.

[0066] The polyaziridine compound present in the second component of the two-component coating system is preferably obtained by reacting at least one polyisocyanate with a compound B having the following structural formula:

[0067]

[0068] wherein R' and R” are as defined above, wherein the molar ratio of compound B to the polyisocyanate is from 2 to 6, more preferably from 2 to 4, most preferably from 2 to 3, and wherein m is as defined above. The reaction of the polyisocyanate with compound B can be carried out by bringing an equal amount of the polyisocyanate into contact with compound B at a temperature in the range from 0 °C to 110 °C, more suitably from 20 °C to 110 °C, more suitably from 40 °C to 95 °C, even more suitably from 60 °C to 85 °C, in the presence of, for example, a tin catalyst (such as dibutyltin dilaurate) or a bismuth catalyst (such as bismuth neodecanoate). A solvent can be used, such as dimethylformamide DMF, acetone and / or methyl ethyl ketone. The polyisocyanate contains at least 2 isocyanate groups, preferably on average at least 2.5 isocyanate groups, more preferably on average at least 2.8 isocyanate groups. A mixture of polyisocyanates can also be used as starting material. Preferred polyisocyanates are polyisocyanates having aliphatic reactivity. The term "polyisocyanate having aliphatic reactivity" refers to a compound in which all isocyanate groups are directly bonded to an aliphatic or cycloaliphatic hydrocarbon group, regardless of whether aromatic hydrocarbon groups are also present. The polyisocyanate having aliphatic reactivity can be a mixture of polyisocyanates having aliphatic reactivity. Preferred polyisocyanates having aliphatic reactivity are 1,5-pentamethylene diisocyanate PDI, 1,6-hexamethylene diisocyanate HDI, isophorone diisocyanate IPDI, 4,4'-dicyclohexylmethane diisocyanate H12MDI, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, p-tetramethylxylene diisocyanate (p-TMXDI) and its meta isomer, and higher molecular weight variants, such as their isocyanurates or iminooxadiazinediones or urethanes or uretidiones. More preferred polyisocyanates having aliphatic reactivity are 1,5-pentamethylene diisocyanate PDI, 1,6-hexamethylene diisocyanate HDI, isophorone diisocyanate IPDI, 4,4'-dicyclohexylmethane diisocyanate H12MDI, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, the isocyanurates or iminooxadiazinediones of tetramethylxylene diisocyanate TMXDI. Even more preferred polyisocyanates having aliphatic reactivity are the isocyanurates or iminooxadiazinediones of 1,6-hexamethylene diisocyanate, the isocyanurates or iminooxadiazinediones of 1,5-pentamethylene diisocyanate, the isocyanurates or iminooxadiazinediones of IPDI. A suitable HDI-containing iminooxadiazinedione trimer is N3900. A suitable HDI-containing urethane is XP2860. Suitable uretdiones containing HDI are those available from Covestro N3400. Suitable HDI-based isocyanurate trimers can be obtained, for example, from Covestro( N3600), Vencorex (Tolonate TM HDT LV), Asahi Kasei (Duranate TM TPA-100), Evonik( HT 2500 / LV) and Tosoh( HXR LV). Compound B is preferably 1-(2-hydroxyethyl)ethylenimine (CAS No. 1072-52-2).

[0069] The polyaziridine compound present in the second component of the two-component coating system is preferably obtained by a method comprising at least the following step (i):

[0070] (i) Reacting compound B with a polyisocyanate.

[0071] The reaction of compound B with the polyisocyanate (step (i)) can be carried out, for example, by contacting an equal amount of the polyisocyanate with the adduct in the presence of, for example, a tin catalyst (such as dibutyltin dilaurate) at atmospheric pressure at a temperature in the range from 20 °C to 110 °C, more suitably from 40 °C to 95 °C.

[0072] Examples of preferred polyaziridine compounds according to the invention are

[0073]

[0074] Another aspect of the present invention is a two-component coating system, the two-component coating system comprising a first component and a second component, each of the first component and the second component being separate and different from each other, wherein the first component comprises a carboxylic acid functional polymer dissolved and / or dispersed, preferably dispersed, in an aqueous medium, and wherein the second component is a crosslinker composition, the crosslinker composition comprising at least one polyaziridine compound as defined herein and further comprising at least one additional component, such as the remaining starting materials, by-products, and / or solvents used to prepare the polyaziridine compounds according to the present invention. The crosslinker composition may comprise only one polyaziridine compound according to the present invention, but may also contain more than one polyaziridine compound according to the present invention. For example, when a mixture of polyisocyanates is used as the starting material for preparing polyaziridines, a mixture of polyaziridine compounds is obtained. After the polyaziridine compounds have been obtained, the polyaziridine compounds may be separated, the reaction products may be used without further purification, or the solvents used to prepare the polyaziridine compounds may be removed from the composition obtained in the preparation of the polyaziridine compounds according to the present invention. The amount of polyaziridine compound in the crosslinker composition is generally at least 10% by weight, often generally at least 15% by weight and most commonly at least 25% by weight, relative to the total amount of the composition. The amount of polyaziridine compound as defined in the present invention present in the crosslinker composition is preferably at least 60% by weight, more preferably at least 80% by weight, and most preferably at least 99% by weight, relative to the total amount of the crosslinker composition. The molecular weight of the polyaziridine compound in the crosslinker composition ranges from 840 daltons to 5000 daltons. The preferred molecular weight is as described above, and the molecular weight of the polyaziridine compound is determined using MALDI-TOF-MS as described in the experimental section below. MALDI-TOF-MS refers to matrix-assisted laser desorption ionization time-of-flight mass spectrometry.

[0075] Relative to the total weight of the crosslinker composition, the amount of aziridine-functional molecules having a molecular weight of less than 250 daltons, more preferably less than 350 daltons, even more preferably less than 450 daltons, even more preferably less than 550 daltons and even more preferably less than 820 daltons present in the crosslinker composition is preferably less than 1.5% by weight, more preferably less than 1% by weight, even more preferably less than 0.5% by weight, and most preferably less than 0.1% by weight, wherein the molecular weight is determined using LC-MS as described in the following experimental section.

[0076] The average number of aziridine groups having the structural formula (C) in each aziridine-group-containing molecule in the crosslinker composition

[0077]

[0078] Preferably at least 1.8, more preferably at least 2, even more preferably at least 2.2 and preferably less than 10, more preferably less than 6 and most preferably less than 4. Most preferably, the average number of aziridinyl groups in each aziridinyl group-containing molecule in the crosslinking agent composition is from 2.2 to 3. The calculated average amount of urethane bonds is at least 5% by weight, more preferably at least 5.5% by weight, more preferably at least 6% by weight, more preferably at least 9% by weight, more preferably at least 12% by weight, and preferably less than 25% by weight, preferably less than 20% by weight, relative to the total weight of the polyaziridine compound present in the crosslinking agent composition.

[0079] In view of the potential water sensitivity of the polyaziridine compound as defined herein, the crosslinking agent composition preferably does not contain a large amount of water, and more preferably does not contain water. Not containing a large amount of water means less than 15% by weight, preferably less than 5% by weight, more preferably less than 1% by weight and most preferably less than 0.1% by weight. In view of the potential water sensitivity of the polyaziridine compound as defined herein, water is preferably not deliberately added to the composition (i.e., a small amount of water may be present in the compounds used to prepare the polyaziridine compound according to the present invention).

[0080] The polyaziridine compound according to the present invention preferably has a Brookfield viscosity at 25 °C of at least 10,000 mPa·s, more preferably at least 20,000 mPa·s, more preferably at least 50,000 mPa·s, and preferably at most 1,000,000 mPa·s, more preferably at most 500,000 mPa·s, even more preferably at most 200,000 mPa·s at 25 °C. As used herein, the Brookfield viscosity is determined according to ISO2555-89. In an alternative embodiment, the viscosity of the polyaziridine is measured at 25 °C with a Brookfield having spindle S63 in 80% solids in dimethylformamide (DMF). The viscosity measured according to this method is preferably in the range of 300 mPa·s to 20,000 mPa·s, more preferably in the range of 500 mPa·s to 12,000 mPa·s, and most preferably in the range of 700 mPa·s to 3,000 mPa·s.

[0081] The carboxylic acid functional polymer present in the first component of the two-component coating system contains carboxylic acid groups and / or carboxylate groups, and the carboxylic acid groups and / or carboxylate groups preferably do not contain covalent bonds that prevent these groups from undergoing chemical reactions with the aziridine moieties present in the polyaziridine compound. As used herein, the amount of carboxylic acid groups present in the carboxylic acid functional polymer is the total amount of deprotonated and protonated carboxylic acid groups present in the polymer to be crosslinked, i.e., in the carboxylic acid functional polymer. Thus, the amount of carboxylic acid groups present in the carboxylic acid functional polymer is the total amount of carboxylate groups and carboxylic acid groups present in the carboxylic acid functional polymer. The polymer to be crosslinked preferably contains at least partially base-neutralized carboxylate groups. Preferably, at least part of the base is a volatile base. Preferably, at least a portion of the carboxylic acid groups present in the crosslinkable carboxylic acid functional polymer undergoes deprotonation to obtain carboxylate groups. Deprotonation is achieved by neutralizing the carboxylic acid functional polymer with a base. Examples of suitable bases are ammonia, secondary amines, tertiary amines, LiOH, NaOH, and / or KOH. Examples of secondary and tertiary amines are as described above. The preferred base is a tertiary amine. Preferred tertiary amines are as described above. Most preferred is triethylamine. Before combination with the second component, the pH of the first component is preferably at least 7, more preferably at least 7.5, even more preferably at least 8, and even more preferably at least 8.5.

[0082] Non-limiting examples of crosslinkable carboxylic acid functional polymers are vinyl polymers (such as styrene-acrylic acid), (meth)acrylic acid copolymers, vinyl acetate (co)polymers (such as vinyl acetate-vinyl chloride-ethylene polymers), polyurethanes, condensation polymers (such as polyesters, polyamides, polycarbonates), and hybrids of any of these polymers, wherein at least one of the two polymers has a carboxylic acid functionality. The carboxylic acid functional polymer is preferably selected from the group consisting of: polyesters, polycarbonates, polyamides, vinyl polymers, polyacrylates, polymethacrylates, poly(acrylate-copoly-methacrylate), polyurethanes, poly(urethane-copoly-acrylate), poly(urethane-copoly-methacrylate), poly(urethane-copoly-acrylate-copoly-methacrylate), polyureas, and mixtures thereof. Preferably, the vinyl polymer means a polymer containing reaction residues of styrene with acrylate and / or methacrylate. In one embodiment of the present invention, the preferred crosslinkable carboxylic acid functional polymers are selected from the group consisting of: vinyl polymers, polyacrylates, polymethacrylates, poly(acrylate-copoly-methacrylate), and mixtures thereof. In another embodiment, the carboxylic acid functional polymer is selected from the group consisting of: polyurethanes, poly(urethane-copoly-acrylate), poly(urethane-copoly-methacrylate), poly(urethane-copoly-acrylate-copoly-methacrylate), polyureas, and mixtures thereof.

[0083] The present invention also relates to a coating composition which is obtained by mixing the first component and the second component of a two-component coating system just before applying the coating composition, wherein the coating composition contains amounts of aziridinyl groups Q and carboxylic acid groups such that the stoichiometric amount (SA) of aziridinyl groups Q on the carboxylic acid groups is preferably from 0.1 to 2.0, more preferably from 0.2 to 1.5, even more preferably from 0.25 to 0.95, and most preferably from 0.3 to 0.8. The pH of the coating composition is preferably at least 7.5, more preferably at least 8, even more preferably at least 8.5, and most preferably at least 9.

[0084] The present invention also relates to a substrate having a coating, wherein the coating is obtained by: (i) applying the coating composition as described above to the substrate, and (ii) drying the coating composition by evaporating the volatile matter. The drying of the coating composition is preferably carried out at a temperature below 160°C, preferably at a temperature below 90°C, more preferably at a temperature below 50°C, and most preferably at ambient temperature. The coating composition according to the present invention can be applied to any kind of substrate, such as wood, leather, concrete, textiles, plastics, vinyl floors, glass, metals, ceramics, paper, wood-plastic composites, glass fiber reinforcements. The thickness of the dry coating on the substrate is preferably from 1 μm to 200 μm, more preferably from 5 μm to 150 μm, and most preferably from 15 μm to 90 μm. In the case where the coating composition is an ink composition, the thickness of the dry ink is preferably from 0.005 μm to 35 μm, more preferably from 0.05 μm to 25 μm, and most preferably from 4 μm to 15 μm.

[0085] Another aspect of the present invention is a polyaziridine compound having:

[0086] a) 2 to 6 of the following structural units (A):

[0087]

[0088] wherein

[0089] m is an integer from 1 to 6, preferably m is 1; and

[0090] both R' and R” are H,

[0091] b) one or more linking groups, wherein each of these linking groups links two of the structural units A, and wherein the linking groups consist of: (i) at least two aliphatic hydrocarbon functional groups or at least two alicyclic hydrocarbon functional groups, and (ii) an isocyanurate functional group or an iminooxadiazinedione functional group, and wherein side groups are present on the linking groups, and wherein the side groups have the following structural formula:

[0092]

[0093] n' is the number of repeating units and is an integer from 1 to 50, preferably from 2 to 30, more preferably from 5 to 20.

[0094] X is O or NH, preferably X is O,

[0095] In each repeating unit, R 7 and R 8 are independently H or CH 3 ,

[0096] R 9 is an aliphatic hydrocarbon group preferably having 1 to 8 carbon atoms, or an alicyclic hydrocarbon group preferably having 4 to 10 carbon atoms, and

[0097] R 10 contains at most 20 carbon atoms and is an aliphatic, alicyclic or aromatic hydrocarbon group, or a combination thereof, and

[0098] c) a molecular weight in the range of 840 to 5000 daltons.

[0099] The presence of the side groups results in a decrease in the viscosity of the polyaziridine compound and thus easier miscibility with the polymer to be crosslinked. In a preferred embodiment, one of R 7 and R 8 is H and the other R 7 or R 8 is CH 3 . In another more preferred embodiment, R 7 and R 8 are H. R 10 is preferably an aliphatic hydrocarbon group having 1 to 20 carbon atoms (preferably CH 3 ), an alicyclic hydrocarbon group having 5 to 20 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms. The polyaziridine compound preferably contains 2 structural units, and the linking group preferably consists of an array of the following consecutive functional groups: a first alicyclic hydrocarbon functional group, an isocyanurate functional group or an iminooxadiazinedione functional group, and a second alicyclic hydrocarbon functional group, and R 9 is an alicyclic hydrocarbon group, wherein the first alicyclic hydrocarbon functional group and the second alicyclic hydrocarbon functional group are the same as R 9 , more preferably, the linking group consists of an array of the following consecutive functional groups: a first aliphatic hydrocarbon functional group, an isocyanurate functional group or an iminooxadiazinedione functional group and a second aliphatic hydrocarbon functional group, and R 9 is an aliphatic hydrocarbon functional group, wherein the first aliphatic hydrocarbon functional group and the second aliphatic hydrocarbon functional group are the same as R9 is the same. Preferably, the polyaziridine compound contains polyoxyethylene (-O-CH2-CH2-) in an amount of preferably at least 0.1% by weight, more preferably at least 6% by weight, still more preferably at least 10% by weight and preferably less than 45% by weight, more preferably less than 25% by weight, most preferably less than 16% by weight, based on the polyaziridine compound x groups and / or polyoxypropylene (-O-CHCH3-CH2-) x groups. Preferably, the polyaziridine compound contains polyoxyethylene (-O-CH2-CH2-) in an amount of preferably at least 0.1% by weight, more preferably at least 6% by weight, still more preferably at least 10% by weight and preferably less than 45% by weight, more preferably less than 45% by weight and most preferably less than 16% by weight, based on the polyaziridine compound x groups. The polyaziridine compound containing polyoxyethylene (-O-CH2-CH2-) x groups is preferably at least a reaction product of compound (B), a polyisocyanate and an alkoxypoly(ethylene glycol) (preferably methoxypoly(ethylene glycol) (MPEG)) and / or poly(ethylene glycol). The reaction product can be obtained by reacting at least compound B, a polyisocyanate and an alkoxypoly(ethylene glycol) and / or poly(ethylene glycol), and the compound B has the following structural formula

[0100]

[0101] wherein R' and R” are as defined above. The reaction product can also be obtained by reacting a polyisocyanate with an alkoxypoly(ethylene glycol) and / or poly(ethylene glycol) and reacting the compound thus obtained with compound (B). The reaction product can also be obtained by reacting compound (B) with a polyisocyanate and reacting the compound thus obtained with an alkoxypoly(ethylene glycol) and / or poly(ethylene glycol). In the polyaziridine compound as defined above, the amount of the alkoxypoly(ethylene glycol) (preferably methoxypoly(ethylene glycol) (MPEG)) and / or poly(ethylene glycol) (PEG) chain having an average molecular weight higher than 2200 daltons, preferably higher than 1600 daltons, is preferably less than 35% by weight, more preferably less than 15% by weight, more preferably less than 5% by weight, and most preferably 0% by weight. The average molecular weight of the methoxypoly(ethylene glycol) (MPEG) and / or poly(ethylene glycol) (PEG) chain present in the polyaziridine compound is preferably lower than 1100 daltons, more preferably lower than 770 daltons, and most preferably lower than 570 daltons. The average molecular weight is determined by multiplying the OH functionality of the polyol by the equivalent weight of the polyol. The OH functionality of the polyol is given by the supplier of the polyol. In the case where the polyol is a diol, the OH functionality is 2. The equivalent weight of the polyol is calculated by dividing 56100 by the OH value of the polyol. The OH value of the polyol is measured by titrating a known mass of the polyol according to ISO 14900 (2017) and is expressed as mg KOH / g polyol.

[0102] The present invention will now be illustrated by reference to the following examples. All parts, percentages, and ratios are by weight unless otherwise indicated.

[0103] AV determination

[0104] The acid value (AV) based on solid matter of the sample was determined based on the ASTM D1639-90 (1996)e1 standard. In this process, the sample dissolved in a good solvent was titrated with a potassium hydroxide alcohol solution (KOH) of known concentration. According to the following formula, the difference in titration volume between the sample and the blank is a measure of the acid value based on solids: AV = [(Vblank - Vsample) * N KOH * 56.1] / (W * S / 100), where AV is the acid value based on solids in mg KOH / g solid material, Vblank is the volume of the KOH solution used in the blank, Vsample is the volume of the KOH solution used in the sample, N KOHis the normality of the KOH solution, W is the sample weight in grams, and S is the solids content of the sample in %. The measurements are performed in duplicate using a potentiometric endpoint on a Metrohm 702SM Titrino titrator (the measurement results are accepted if the difference between duplicate runs is < 0.1 mg KOH / g of solid matter).

[0105] Chemical resistance

[0106] Chemical resistance tests based on the DIN 68861-1:2011-01 standard.

[0107] Unless otherwise stated, the chemical resistance tests are as follows:

[0108] Compared to the carboxylic acid functional groups, the coating composition consists of 0.9 stoichiometric amount (SA) of total carboxylic acid-reactive functional groups (such as aziridine). The coating composition is processed as described in the examples and then cast using a wire bar coater at a wet layer thickness of 100 μm. After casting, the film is dried at 25 °C for 1 hour and then annealed at 50 °C for 16 hours. Subsequently, a piece of absorbent cotton is soaked in ethanol:demineralized water (by weight) at a ratio of 1:1 and placed on the film for 60 minutes (unless otherwise stated). After removing the absorbent cotton and allowing it to recover overnight, the spots are scored according to the following grades:

[0109] 1 Complete coating degradation

[0110] 2 Structural damage to the coating

[0111] 3 Severe markings on the coating, visible from multiple directions

[0112] 4 Slight markings on the coating, visible from a specific angle

[0113] 5 No markings or gloss changes observed

[0114] Viscosity measurement:

[0115] The apparent viscosity is determined according to ISO 2555:2018. The measurements are performed at 23 °C on a Brookfield DVE-LV viscometer (single cylinder geometry) at 60 rpm. Select the spindle from S62, S63, or S64, using the smallest numbered spindle (i.e., the largest spindle) that gives a torque reading between 10% and 100%.

[0116] Analysis of the low molecular weight fraction by LC-MS

[0117] LC system: Agilent 1290 Infinity II; Detector No. 1: Agilent 1290 Infinity IIPDA; Detector No. 2: Agilent iFunnel 6550 Q-TOF-MS.

[0118] The LC-MS analysis of the low molecular weight fraction was performed using the following procedure. A methanol solution of approximately 100 mg / kg of the material was prepared gravimetrically and stirred. 0.5 μl of this solution was injected into a UPLC equipped with ESI-TOF-MS detection. The column used was a 100×2.1 mm, 1.8 μm, Waters HSS T3 C18 operating at 40 °C. The flow rate was 0.5 ml / min. -1 . The solvents used were 10 mM NH 3 adjusted to pH 9.0 with NH 4 CH 3 COO aqueous solution (eluent A), acetonitrile (B), and THF (C). Two binary gradients were applied, one from 80 / 20 A / B to 1 / 99 A / B over 10 minutes and the other from 1 / 99 A / B to 1 / 49 / 50 A / B / C over 5 minutes, after which the starting conditions (80 / 20 A / B) were applied. Assuming that all components have a linear MS response over all response ranges and that the ionization efficiency of all components is equal, the total ion current signal was integrated. In the case of co-elution, the extracted ion chromatogram for that particular species was integrated. The integrated signal for a particular low molecular weight peak was divided by the total integrated sample signal to yield the fraction of that low molecular weight substance.

[0119] MALDI-ToF-MS

[0120] All MALDI-ToF-MS spectra were acquired using a Bruker Ultraflextreme MALDI-ToF mass spectrometer. The instrument was equipped with a Nd:YAG laser emitting at 1064 nm and a collision cell (not used for these samples). Using the reflector, spectra were acquired in positive ion mode in the highest resolution mode providing accurate mass (range 60 - 7000 m / z). Mass calibration was performed using cesium triiodide (range 0.3 - 3.5 kDa) (calibration method: IAV molecular characterization, code MC-MS-05). The laser energy was 20%. The sample was dissolved in THF at approximately 50 mg / mL. The matrix used was: DCTB (trans-2-[3-(4-tert-butylphenyl)-2-methyl-2-propenylidene]malononitrile), CAS number 300364-84-5. The matrix solution was prepared by dissolving 20 mg in 1 mL of THF.

[0121] Sodium iodide was used as the salt (NaI, CAS number 7681-82-5); 10 mg was dissolved in 1 ml of THF, and one drop of MeOH was added. Sample:matrix:salt ratio = 10:200:10 (μl). After mixing, 0.5 μL was spotted onto a MALDI plate and air-dried. The peaks measured in the MALDI spectrum are the sodium adducts of the polyaziridine compounds, and in the context of this specification, the molecular weight (MW) of the polyaziridine compound corresponds to MW = observed [M + M 阳离子 – M 阳离子 , where observed [M + M 阳离子 is the MALDI-TOF MS peak, and M 阳离子 is the exact mass of the cation used to prepare the adduct (in this case, M 阳离子 of sodium = 23.0 Da). The polyaziridine compound can be identified by comparing the MW with the exact molecular mass of the theoretical structure (i.e., the sum of the non-isotopic average atomic masses of its constituent atoms) using a maximum deviation of 0.6 Da.

[0122] Synthesis of P1 of Waterborne Polyurethane

[0123] A 1-liter flask (equipped with a thermometer and overhead stirrer) was charged with 29.9 grams of dimethylolpropionic acid, 282.1 grams of a polypropylene glycol having a calculated average molecular weight (M) of 2000 Da and an OH value of 56 ± 2 mg KOH / g, 166.5 grams of a polypropylene glycol having a calculated average molecular weight (M) of 1000 Da and an OH value of 112 ± 2 mg KOH / g, and 262.8 grams of isophorone diisocyanate (the average molecular weight of each of the polyols was calculated from its OH value according to the equation: M = 2 * 56100 / [OH value in mg KOH / g polypropylene glycol). The reaction mixture was placed under N 2Under an atmosphere, it was heated to 50 °C, and then 0.07 g of dibutyltin dilaurate was added to the reaction mixture. An exothermic reaction was observed; however, in order to keep the reaction temperature from exceeding 97 °C, appropriate measures were needed. The reaction was maintained at 95 °C for one hour. As determined according to ISO 14896 Method A (2009), the NCO content of the resulting polyurethane P1' on a solids basis was 7.00% (theoretically 7.44%), and the acid value of polyurethane P1' was 16.1 ± 1 mg KOH / g of polyurethane P1'. The polyurethane P1' was cooled to 60 °C, and 18.7 g of triethylamine was added, and the resulting mixture was stirred for 30 minutes. Subsequently, an aqueous dispersion of polyurethane P1' (the aqueous dispersion of polyurethane P1' is further referred to as P1) was prepared as follows: The mixture of polyurethane P1' and triethylamine thus prepared was fed into a mixture of 1100 g of demineralized water, 19.5 g of nonylphenol ethoxylate (9 ethoxylate groups), and 4.0 g of triethylamine at room temperature over a period of 60 minutes. After the feeding was completed, the mixture was stirred for an additional 5 minutes, and then 111.2 g of hydrazine (16 wt% aqueous solution) was added to the mixture. The aqueous dispersion of polyurethane P1' thus prepared was stirred for an additional 1 h to obtain P1.

[0124] Preparation Example 2: Synthesis of Waterborne Acrylic Polymer A1

[0125] In a 2 L four-necked flask equipped with a thermometer and an overhead stirrer, sodium dodecyl sulfate (30% solids in aqueous solution, 18.6 g of the solution) and demineralized water (711 g) were charged. The reactor phase was placed under an N 2 atmosphere and heated to 82 °C. A mixture of demineralized water (112 g), sodium dodecyl sulfate (30% solids in water, 37.2 g of the solution), methyl methacrylate (209.3 g), n-butyl acrylate (453.56 g), and methacrylic acid (34.88 g) was placed in a large feed funnel and emulsified with an overhead stirrer (monomer feed). Ammonium persulfate (1.75 g) was dissolved in demineralized water (89.61 g) and placed in a small feed funnel (initiator feed). Ammonium persulfate (1.75 g) was dissolved in demineralized water (10.5 g), and this solution was added to the reactor phase. Immediately thereafter, 5 vol% of the monomer feed was added to the reactor phase. Then the reaction mixture was allowed to exotherm to 85 °C and held at 85 °C for 5 minutes. Then, the remaining monomer feed and initiator feed were fed into the reaction mixture over 90 minutes while maintaining the temperature at 85 °C. After the feeding was completed, the monomer feed funnel was rinsed with demineralized water (18.9 g), and the reaction temperature was maintained at 85 °C for 45 minutes. Subsequently, the mixture was cooled to room temperature, adjusted to pH = 7.2 with an ammonia solution (6.25 wt% in demineralized water), and adjusted to 40% solids with additional demineralized water.

[0126] Genotoxicity Test

[0127] By The genotoxicity of the examples and comparative examples was evaluated by the Toxys test (Toxys, Leiden, the Netherlands). The ToxTracker test is a set of several validated green fluorescent protein (GFP)-based mouse embryonic stem (mES) reporter gene cell lines that can be used to identify the biological activity and potential carcinogenic properties of newly developed compounds in a single test. This method uses a two-step approach.

[0128] In the first step, dose range finding was performed using wild-type mES cells (strain B4418). Twenty different concentrations of each compound were tested, starting with 10 mM in DMSO as the highest concentration and 19 consecutive two-fold dilutions.

[0129] Next, the genotoxicity of the examples and comparative examples was evaluated using specific genes linked to reporter genes for the detection of DNA damage; the specific genes being the Bscl2 (as elucidated by US9695481B2 and EP2616484B1) and Rtkn (Hendriks et al., Toxicol. Sci. 2015, 150, 190 - 203) biomarkers. Genotoxicity was evaluated at 10%, 25% and 50% cytotoxicity in the absence and presence of a metabolic system based on rat S9 liver extract (aroclor1254-induced rats, Moltox, Boone, NC, USA). Independent cell lines were seeded into 96-well cell culture plates and fresh ES cell medium containing the diluted test substance was added to the cells 24 hours after the cells were seeded into the 96-well plates. For each compound tested, five concentrations were tested at two-fold dilutions. The highest sample concentration would induce significant cytotoxicity (50 - 70%). In the case of no or low cytotoxicity, 10 mM or the maximum soluble mixture concentration was used as the maximum test concentration. Cytotoxicity was determined by cell counting using a Guava easyCyte 10HT flow cytometer (Millipore) after 24 hours of exposure.

[0130] The GFP reporter gene induction was always compared to vehicle control treatment. For a given compound, the DMSO concentration in all wells was similar and never exceeded 1%. All compounds were tested in at least three completely independent replicate experiments. All experiments included a positive control treatment with cisplatin (DNA damage). Metabolism was evaluated by addition of S9 liver extract. Cells were exposed to five concentrations of the test compound for 3 h in the presence of S9 and the required cofactors (RegenSys A+B, Moltox, Boone, NC, USA). After washing, the cells were incubated in fresh ES cell medium for 24 h. After 24 h of exposure, GFP reporter gene induction was determined using a Guava easyCyte 10HT flow cytometer (Millipore). GFP expression was determined only in intact single cells. The mean GFP fluorescence and cell concentration in each well were measured and used for cytotoxicity assessment. Data were analyzed using ToxPlot software (Toxys, Leiden, the Netherlands). The reported induction levels were at the compound concentrations that induced 10%, 25% and 50% cytotoxicity after 3 h of exposure in the presence of S9 rat liver extract and a 24 h recovery or alternatively after 24 h of exposure in the absence of S9 rat liver extract.

[0131] The positive induction level of the biomarker was defined as equal to or higher than 2-fold induction at at least one of 10%, 25% and 50% cytotoxicity in the absence or presence of the metabolic system rat S9 liver extract; weak positive induction was defined as higher than 1.5-fold and lower than 2-fold induction (but lower than 2-fold at 10%, 25% and 50% cytotoxicity) at at least one of 10%, 25% and 50% cytotoxicity in the absence or presence of the metabolic system rat S9 liver extract, and negative induction was defined as lower than or equal to 1.5-fold induction at 10%, 25% and 50% cytotoxicity in the absence or presence of the metabolic system based on rat S9 liver extract.

[0132] Components and Abbreviations Used:

[0133] Dimethylformamide (CAS number 68-12-2) was obtained from cros Organics (a subsidiary of Thermo Fisher Scientific).

[0134] Di(propylene glycol) dimethyl ether (Proglyde DMM, CAS number 111109-77-4) was obtained from Dow Inc

[0135] Trimethylolpropane tris(2-methyl-1-aziridinepropionate), CAS No. 64265-57-2, CX-100 was obtained from DSM.

[0136] Pentaerythritol tris(3-(1-aziridinyl)propionate), CAS No. 57116-45-7 was obtained from ABCR.

[0137] IPDI (5-isocyanato-1-(isocyanatomethyl)-1,3,3-trimethylcyclohexane, I, isophorone diisocyanate, CAS No. 4098-71-9) was obtained from Covestro.

[0138] Methoxypolyethylene glycol with a number-average molecular weight of 1000 Da (CAS No. 9004-74-4) was obtained from Tokyo Chemical Industry Co., Ltd.

[0139] T 1890 / 100, an isocyanurate based on isophorone diisocyanate (CAS No. 67873-91-0) was obtained from Evonik.

[0140] N3600 was obtained from Covestro.

[0141] 1-Methyl-2-propyl acetate (propylene glycol methyl ether acetate, CAS No. 108-65-6) was obtained from Shell Chemicals.

[0142] 1-(2-Hydroxyethyl)ethylenediamine) (CAS No. 1072-52-2) was obtained from Tokyo Chemical Industry Co., Ltd.

[0143] XTJ-436 (CAS No. 118270-87-4) was obtained from Huntsman.

[0144] Bismuth neodecanoate (CAS No. 34364-26-6) was obtained from TIB chemicals AG (Mannheim, Germany).

[0145] Hydrazine (16% aqueous solution, CAS No. 302-01-2) was obtained from Honeywell.

[0146] Dimethylolpropionic acid (DMPA, CAS No. 4767-03-7) was obtained from Perstop Polyols.

[0147] Triethylamine (TEA, CAS No. 121-44-8) was obtained from Arkema

[0148] 1-Propanol (CAS No. 71-23-8) was obtained from Sigma-Aldrich.

[0149] Tin 2-ethylhexanoate (CAS No. 301-10-0) was obtained from Sigma-Aldrich.

[0150] Dibutyltin dilaurate (CAS No. 77-58-7) was obtained from Sigma-Aldrich.

[0151] D3403 was obtained from Evonik.

[0152] Polypropylene glycol with a number average molecular weight of 1000 Da and a number average molecular weight of 2000 Da was obtained from BASF.

[0153] 3-Methyl-1-phenyl-2-phospholene 1-oxide (CAS No. 707-61-9) was obtained from Sigma-Aldrich.

[0154] 1-Butanol (CAS No. 71-36-3) was obtained from Sigma-Aldrich.

[0155] Sodium dodecyl sulfate (30% aqueous solution, CAS No. 73296-89-6) was obtained from BASF.

[0156] Methyl methacrylate (CAS No. 80-62-6) was obtained from Lucite Int.

[0157] n-Butyl acrylate (CAS No. 141-32-2) was obtained from Dow Chemical.

[0158] Methacrylic acid (CAS No. 79-41-4) was obtained from Lucite Int.

[0159] Ammonium persulfate (CAS No. 7727-54-0) was obtained from United Initiators.

[0160] Ammonia (25% aqueous solution, CAS No. 1336-21-6) was obtained from Merck.

[0161] Comparative Example 1

[0162] Comparative Example 1 is trimethylolpropane tris(2-methyl-1-aziridinepropionate), CAS No. 64265-57-2, obtained from DSM. The chemical structure is shown below.

[0163]

[0164] For reference, based on the procedure from the DIN 68861-1:2011-01 standard, a spot test on the coated surface was used to evaluate the performance of trimethylolpropane tris(2-methyl-1-aziridinepropionate) as a crosslinking agent. For these tests, 0.23 parts of the compound were mixed with 0.60 parts of Proglyde TM DMM (dipropylene glycol dimethyl ether, a mixture of isomers), and incubated at 80 °C for 10 minutes with regular stirring. Subsequently, 0.56 parts of the resulting solution were added to 20 parts of P1 with continuous stirring, and the resulting mixture was further stirred for 30 minutes. Then, the coating composition was filtered and applied to a Leneta test card (Test C1-1) using a 100 μm wire bar coater. The film was dried at 25 °C for 16 hours, then annealed at 50 °C for 1 hour, and further dried at 25 °C for 24 hours. Subsequently, a piece of cotton wool was dipped into 1:1 EtOH:demineralized water and placed on the film for various time intervals. After removing the EtOH and allowing to recover for 60 minutes, the following results were obtained (rating 1 indicates complete degradation of the film, 5 indicates no visible damage):

[0165] Ethanol spot test

[0166]

[0167] Genotoxicity test

[0168]

[0169]

[0170] The genotoxicity test results showed that the crosslinking agent of Comparative Example 1 was genotoxic.

[0171] Example 1

[0172] 3.83 grams of 1-(2-hydroxyethyl)ethylenediamine) (CAS No. 1072-52-2, obtained from Tokyo Chemical Industry), 12.21 grams of poly(ethylene glycol) monomethyl ether with an average Mn of 1000 Da, and 126 grams of dimethylformamide were charged into a reaction flask equipped with a thermometer. The mixture was stirred with a mechanical overhead stirrer under a nitrogen atmosphere and heated to 50 °C, after which 0.12 grams of bismuth neodecanoate was added to the flask, and a mixture of 15.00 grams T 1890 / 100 in 63 grams of dimethylformamide was fed into the reaction flask over 30 minutes. After that, the mixture was further heated to 80 °C. Samples were taken at regular intervals, and the reaction progress was monitored using a Bruker Alpha FT-IR spectrometer until in the 2200 - 2300 cm-1 Observation was continued until no NCO stretching change was observed. Subsequently, 0.36 g of 1-butanol was added to the mixture, and the reaction was further continued until the above NCO stretching peak completely disappeared. The solvent was removed under vacuum to obtain an opaque waxy solid. The calculated molecular weights of the theoretical main components were 927.62 Da (three aziridines), 1797.12 (two aziridines, 21 EG repeating units), and 1841.15 Da (two aziridines, 22 EG repeating units), and the chemical structures are shown below.

[0173]

[0174] The molecular weight was confirmed by Maldi-TOF-MS: calculated [M+Na+] = 950.62 Da; observed [M+Na+] = 950.52 Da.

[0175]

[0176] The molecular weight was confirmed by Maldi-TOF-MS: calculated [M+Na+] = 1820.12 Da; observed [M+Na+] = 1820.15 Da.

[0177]

[0178] The molecular weight was confirmed by Maldi-TOF-MS: calculated [M+Na+] = 1864.15 Da; observed [M+Na+] = 1864.20 Da.

[0179] The following components below 820 Da were detected and quantitatively probed by LC-MS:

[0180]

[0181] Present in the composition at 0.04 wt%

[0182] The performance of the synthesized compound as a crosslinking agent was evaluated using spot tests on coated surfaces based on procedures from the DIN 68861-1:2011-01 standard. For these tests, 0.75 parts of the composition were mixed with 0.75 parts of 1-methoxy-2-propyl acetate and incubated at 80 °C for 10 minutes with regular stirring. Subsequently, 1.5 parts of the resulting solution were added to 10 parts of P1 with continuous stirring, and the resulting mixture was further stirred for 30 minutes. Then, the coating composition was filtered and applied to a Leneta test card using a 100 μm wire bar coater (Test 1-1). As a reference, a film was also cast from the same composition lacking the crosslinking agent (Test 1-2). The film was dried at 25 °C for 16 hours, then annealed at 50 °C for 1 hour, and further dried at 25 °C for 24 hours. Subsequently, a piece of cotton wool was immersed in 1:1 EtOH:demineralized water and placed on the film for various time intervals. After removing the EtOH and allowing 60 minutes for recovery, the following results were obtained (rating 1 indicates complete degradation of the film and 5 indicates no visible damage):

[0183] Ethanol spot test

[0184]

[0185] For further performance testing, 1.0 part of the composition was mixed with 1.0 part of 1-methoxy-2-propyl acetate and incubated at 80 °C for 10 minutes with regular stirring. Subsequently, 1.5 parts of the resulting solution were added to 10.5 parts of A1 with continuous stirring, and the resulting mixture was further stirred for 30 minutes. Then, the coating composition was filtered and applied to a Leneta test card using a 100 μm wire bar coater (Test 1-3). As a reference, a film was also cast from the same composition lacking the crosslinking agent (Blank 1-4). The film was dried at 25 °C for 16 hours, then annealed at 50 °C for 1 hour, and further dried at 25 °C for 24 hours. Subsequently, a piece of cotton wool was immersed in 1:1 EtOH:demineralized water and placed on the film for various time intervals. After removing the EtOH and allowing 60 minutes for recovery, the following results were obtained (rating 1 indicates complete degradation of the film and 5 indicates no visible damage):

[0186]

[0187] Genotoxicity test

[0188]

[0189]

[0190] The genotoxicity test results indicate that the crosslinker composition of Example 1 is non-genotoxic.

[0191] Comparative Example 2

[0192] Charge 15.0 g of Desmodur N 3600 and 75 g of dimethylformamide into a reaction flask equipped with a thermometer. Stir the mixture with a mechanical overhead stirrer under a nitrogen atmosphere. Then heat the mixture to 50 °C, after which 6.80 g of 1-(2-hydroxyethyl)ethylenediamine is added. After 15 minutes, 0.03 g of bismuth neodecanoate is charged into the reaction flask, and then it is further heated to 60 °C. Samples are taken at regular intervals and the reaction progress is monitored using a Bruker Alpha FT-IR spectrometer until no NCO stretch is observed at 2200 - 2300 cm -1 −1. The solvent is removed under vacuum to obtain a clear, slightly yellow, highly viscous liquid. The calculated molecular weight of the theoretical main component is 765.47 Da, and the chemical structure is shown below.

[0193]

[0194] The molecular weight was confirmed by Maldi-TOF-MS: calculated [M+K+] = 804.43 Da; observed [M+K+] = 804.27 Da.

[0195] Genotoxicity test

[0196]

[0197] The genotoxicity test results indicate that the reaction product of Comparative Example 2 is genotoxic.

[0198] Example 2

[0199] Charge 3.83 g of 1-(2-hydroxyethyl)ethyleneimine (Cas No. 1072-52-2, obtained from Tokyo Chemical Industry), 12.27 g of XTJ-436 (Cas No. 118270-87-4, obtained from Huntsman) and 126 g of dimethylformamide into a reaction flask equipped with a thermometer. Stir the mixture with a mechanical overhead stirrer under a nitrogen atmosphere and heat it to 50 °C, after which 0.10 g of bismuth neodecanoate is added to the flask, and 15.00 g of The mixture of T1890 / 100 in 95 g of dimethylformamide was fed into the reaction flask within 30 minutes. After that, the mixture was further heated to 80 °C. Samples were taken at regular intervals and the reaction progress was monitored using a Bruker Alpha FT-IR spectrometer until no NCO stretching change was observed at 2200 - 2300 cm -1 −1. Subsequently, 0.36 g of 1-butanol was added to the mixture, and the reaction was further carried out until the above-mentioned NCO stretching peak completely disappeared. The solvent was removed under vacuum to obtain an opaque waxy solid. The calculated molecular weights of the theoretical main components were 927.62 Da (three aziridines), 1814.29 Da (two aziridines, 13 PO repeating units), and 1827.33 Da (two aziridines, 14 PO repeating units), and the chemical structures are shown below.

[0200]

[0201] The molecular weight was confirmed by Maldi-TOF-MS: calculated [M+Na+] = 950.62 Da; observed [M+Na+] = 950.52 Da.

[0202]

[0203] The molecular weight was confirmed by Maldi-TOF-MS: calculated [M+Na+] = 1837.28 Da; observed [M+Na+] = 1837.15 Da.

[0204]

[0205] The molecular weight was confirmed by Maldi-TOF-MS: calculated [M+Na+] = 1895.32 Da; observed [M+Na+] = 1895.15 Da.

[0206] The following components below 820 Da were detected and quantified by LC-MS:

[0207]

[0208] It was present in the composition at 0.10 wt%.

[0209] The performance of the synthesized compound as a crosslinking agent was evaluated using spot tests on coated surfaces based on the procedures from the DIN 68861-1:2011-01 standard. For these tests, 1.03 parts of the composition were mixed with 0.26 parts of dimethylformamide and incubated at 80 °C for 10 minutes with regular stirring. Subsequently, 1.29 parts of the resulting solution were added to 15 parts of P1 under continuous stirring, and the resulting mixture was further stirred for 30 minutes. Then, the coating composition was filtered and applied to a Leneta test card using a 100 μm wire bar coater (Test 2-1). As a reference, a film was also cast from the same composition lacking the crosslinking agent (Test 2-2). The film was dried at 25 °C for 16 hours, then annealed at 50 °C for 1 hour, and further dried at 25 °C for 24 hours. Subsequently, a piece of cotton wool was immersed in 1:1 EtOH:demineralized water and placed on the film for various time intervals. After removing the EtOH and allowing to recover for 60 minutes, the following results were obtained (rating 1 indicates complete degradation of the film, 5 indicates no visible damage):

[0210] Ethanol spot test

[0211]

[0212] For further performance testing, 1.45 parts of the composition were mixed with 0.39 parts of dimethylformamide and incubated at 80 °C for 10 minutes with regular stirring. Subsequently, 1.84 parts of the resulting solution were added to 10.5 parts of A1 under continuous stirring, and the resulting mixture was further stirred for 30 minutes. Then, the coating composition was filtered and applied to a Leneta test card using a 100 μm wire bar coater (Test 2-3). As a reference, a film was also cast from the same composition lacking the crosslinking agent (Blank 2-4). The film was dried at 25 °C for 16 hours, then annealed at 50 °C for 1 hour, and further dried at 25 °C for 24 hours. Subsequently, a piece of cotton wool was immersed in 1:1 EtOH:demineralized water and placed on the film for various time intervals. After removing the EtOH and allowing to recover for 60 minutes, the following results were obtained (rating 1 indicates complete degradation of the film, 5 indicates no visible damage):

[0213]

[0214] Genotoxicity test

[0215]

[0216]

[0217] The genotoxicity test results showed that the crosslinking agent composition of Example 2 had only weakly positive induced genotoxicity.

[0218] Comparative Example 3

[0219] Comparative Example 3 is pentaerythritol tris(3-(1-aziridinyl)propionate), CAS number 57116-45-7, obtained from ABCR. The chemical structure is shown below.

[0220]

[0221] Genotoxicity testing

[0222]

[0223] The genotoxicity test results showed that the crosslinking agent of Comparative Example 3 was genotoxic.

[0224] Comparative Example 4 (Example 5 US-A-5258481)

[0225] Under a nitrogen atmosphere, at 20 - 25 °C, while stirring, 21.3 g (0.354 mol) of 1-propanol was added to 78.7 g of isophorone diisocyanate (IPDI) and 0.01 g of tin 2-ethylhexanoate over a 6-hour period. After standing overnight, 196.3 g (0.883 mol) of IPDI, 74.1 g (0.0628 mol) of Tegomer D3403, and 2.4 g of 3-methyl-1-phenyl-2-phospholene-1-oxide were added. The mixture was heated to 150 °C while stirring. The mixture was maintained at 150 °C until the NCO content was 7.0 wt%. The mixture was cooled to 80 °C, and 333 g of methoxypropyl acetate was added. A solution of isocyanate-functional polycarbodiimide with a solids content of 50.6 wt% and an NCO content of 7.0 wt% based on solids was obtained.

[0226] To 100 g of this isocyanate-functional polycarbodiimide, 7.0 g of 1-(2-hydroxyethyl)ethylenimine (0.08 mol) was added. One drop of dibutyltin dilaurate was added. The mixture was heated to 80 °C while stirring. The mixture was held at 80 °C for 1 hour. FTIR showed a small amount of residual isocyanate signal, which disappeared after a few days. The solution was further diluted with 8.0 g of methoxypropyl acetate to obtain a yellow solution with a solids content of 50.4 wt%. This aziridine-functional carbodiimide contained 3.2 meq of acid-reactive groups (i.e., aziridine and carbodiimide functionality) per gram of solid. The general structure of this carbodiimide is depicted below.

[0227]

[0228] where a, b, and c represent repeating units.

[0229] The Tonghua structure was confirmed by MALDI-TOF-MS, as shown in the following examples:

[0230]

[0231] The molecular weight was confirmed by Maldi-TOF-MS: calculated [M+Na+] = 2043.34 Da; observed [M+Na+] = 2043.32 Da.

[0232] Results of genotoxicity tests:

[0233]

[0234] The results of genotoxicity tests indicated that the crosslinking agent of Comparative Example 4 was genotoxic.

Claims

1. A two-component coating system, the two-component coating system comprising a first component and a second component, each of the first component and the second component being separate and different from each other, wherein the first component comprises a carboxylic acid-functional polymer dissolved and / or dispersed in an aqueous medium, wherein the carboxylic acid-functional polymer comprises carboxylic acid groups and / or carboxylate groups, and the second component comprises a polyaziridine compound having: a) 2 to 6 of the following structural units (A): wherein m is an integer from 1 to 6, and both R' and R” are H; b) one or more linking chains, each of the linking chains linking two of the structural units (A), wherein the linking chain is the shortest continuous chain of atoms linking two structural units (A); c) one or more linking groups, each of the linking groups linking two of the structural units (A), and wherein the linking group consists of: (i) at least two aliphatic hydrocarbon functional groups or at least two cycloaliphatic hydrocarbon functional groups and (ii) an isocyanurate functional group or an iminodioxazine dione functional group, and wherein side groups are present on the linking group, wherein the side group has the following structural formula: n' is the number of repeating units and is an integer from 1 to 50, X is O or NH, In each repeating unit, R 7 and R 8 are independently H or CH 3 , R 9 is an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, and R 10 containing at most 20 carbon atoms and being an aliphatic, alicyclic or aromatic hydrocarbon group, or a combination thereof; and d) a molecular weight in the range of 840 daltons to 5000 daltons, wherein the molecular weight is determined using MALDI-TOF mass spectrometry.

2. The two-component coating system according to claim 1, wherein m is 1.

3. The two-component coating system according to claim 1 or 2, wherein the polyaziridine compound contains 2 or 3 structural units (A).

4. The two-component coating system according to claim 1 or 2, wherein the linking chain consists of 4 to 300 atoms, and the linking chain is a collection of covalently linked atoms, the collection of atoms consisting of i) carbon atoms, ii) carbon and nitrogen atoms, or iii) carbon, oxygen and nitrogen atoms.

5. The two-component coating system according to claim 1 or 2, wherein the number of consecutive C atoms and optionally O atoms between the N atom of the urethane group in the structural unit (A) and the next N atom, the next N atom either being in the linking chain or the N atom of the urethane group of another structural unit (A), is at most 9.

6. The two-component coating system according to claim 1 or 2, wherein the molecular weight of the polyaziridine compound is from 840 daltons to 3800 daltons.

7. The two-component coating system according to claim 1 or 2, wherein X is O and R 7 and R 8 is H.

8. The two-component coating system according to claim 1 or 2, wherein the polyaziridine compound contains 2 structural units (A).

9. The two-component coating system according to claim 8, wherein the linking group consists of the following array of consecutive functional groups consisting of: a first aliphatic hydrocarbon functional group, an isocyanurate functional group or an iminodioxadione functional group, and a second aliphatic hydrocarbon functional group, and R 9 is an aliphatic hydrocarbon group, wherein the first aliphatic hydrocarbon functional group and the second aliphatic hydrocarbon functional group are the same as R 9 is the same.

10. The two-component coating system according to claim 1 or 2, wherein the polyaziridine compound contains at least 0.1% by weight of polyoxyethylene groups relative to the amount of the polyaziridine compound.

11. The two-component coating system according to claim 1 or 2, wherein the polyaziridine compound is obtained by reacting at least a polyisocyanate with a compound B having the following structural formula: wherein the molar ratio of the compound B to the polyisocyanate is from 2 to 6, and wherein m, R' and R” are as defined in claim 1 or 2.

12. The two-component coating system according to claim 11, wherein the polyisocyanate is a polyisocyanate having aliphatic reactivity, wherein all isocyanate groups are directly bonded to an aliphatic or cycloaliphatic hydrocarbon group, regardless of whether an aromatic hydrocarbon group is also present.

13. The two-component coating system according to claim 1 or 2, wherein the second component is a crosslinker composition, the crosslinker composition comprising at least one polyaziridine compound as defined in any one of the preceding claims, and further comprising at least one additional component.

14. The two-component coating system according to claim 13, wherein, relative to the total weight of the crosslinker composition, the amount of aziridine-functional molecules having a molecular weight lower than 820 daltons is less than 1.5% by weight, wherein the molecular weight is determined using LC-MS, and wherein the crosslinker composition contains less than 5% by weight of water.

15. A substrate having a coating, the coating being obtained by: (i) applying a coating composition obtained by mixing the first and second components of the two-component coating system according to any one of the preceding claims to the substrate, and (ii) drying the coating composition by evaporating the volatile matter.

16. A polyaziridine compound having: a) 2 to 6 of the following structural units (A): where m is an integer from 1 to 6; and both R' and R” are H, b) one or more linking chains, each of which linking two of the structural units (A), wherein the linking chain is the shortest continuous chain of atoms linking two structural units (A); c) one or more linking groups, each of which linking two of the structural units (A), and wherein the linking group consists of the following components: (i) at least two aliphatic hydrocarbon functional groups or at least two cycloaliphatic hydrocarbon functional groups, and (ii) an isocyanurate functional group or an iminooxadiazinedione functional group, and wherein side groups are present on the linking group, the side groups having the following structural formula: n' is the number of repeating units and is an integer from 1 to 50, X is O or NH, In each repeating unit, R 7 and R 8 are independently H or CH 3 , R 9 is an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, and R 10 containing at most 20 carbon atoms and being an aliphatic, alicyclic or aromatic hydrocarbon group, or a combination thereof, and d) a molecular weight in the range from 840 daltons to 5000 daltons, wherein the molecular weight is measured using MALDI-TOF mass spectrometry.

17. The polyaziridine compound according to claim 16, wherein X is O, and R 7 and R 8 are independently H.

18. The polyaziridine compound according to claim 16 or claim 17, wherein the polyaziridine compound contains 2 structural units (A).

19. The polyaziridine compound according to claim 16 or claim 17, wherein the linking group consists of an array of the following consecutive functional groups components: A first aliphatic hydrocarbon functional group, an isocyanurate functional group or an iminooxadiazinedione functional group, and a second aliphatic hydrocarbon functional group, and R 9 is an aliphatic hydrocarbon group, wherein the first aliphatic hydrocarbon functional group and the second aliphatic hydrocarbon functional group are the same as R 9 is the same.

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