Polynitrogen aziridine compound

Abstract

The present invention relates to a polyaziridine compound having: a) 2 to 6 of the following structural units (A), where R', R'' are as defined herein and m is an integer from 1 to 6; b) one or more linking chains, where each of these linking chains links two of the structural units A; and c) a molecular weight of from 840 daltons to 5000 daltons. The polyaziridine compound can be used, for example, to crosslink a carboxylic acid functional polymer that is, for example, dissolved and / or dispersed in an aqueous medium.

Description

[0001] The present invention relates to compounds having at least two aziridinyl groups, which can be used for crosslinking carboxylic acid functional polymers that are soluble and / or dispersible in an aqueous medium, for example.

[0002] For many years, there has been an increasing demand for coatings with improved 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 crosslinking. Many crosslinking mechanisms have been studied over the years, and for aqueous dispersions, the most useful ones include isocyanate crosslinking of hydroxyl-functional dispersions, the reaction between carbodiimides and carboxylic acids, epoxy crosslinking, and crosslinking using aziridinyl crosslinkers.

[0003] US-A-5133997 describes a coating composition comprising an aqueous dispersion of a linear aliphatic polyurethane resin, an anionic surfactant, and a crosslinker capable of promoting the curing of the resin. Trimethylolpropane tris(2-methyl-1-aziridinepropionate), CAS No. 64265-57-2, is a polyfunctional aziridine crosslinker used as a crosslinker and is well known to be very active in crosslinking carboxylic acid functional polymers. However, this crosslinker has an adverse genotoxicity profile. US-A-2015118501 relates to an anti-fog coating composition comprising an aqueous polymer dispersion and a crosslinker such as an aziridine crosslinker; in Preparation Example 4, a polyfunctional aziridine crosslinker is prepared by Michael addition of ethoxylated trimethylolpropane triacrylate and 2-methylaziridine. US-A-3763132 relates to a curable composition comprising a carboxyl-containing polymer and an aziridine, such as an adduct of acrylimide and trimethylolpropane trimethacrylate that can be used in coating applications. There is a need in the industry to improve the safety, health, and environmental characteristics of adhesives, inks, and coatings, as well as the substances used to prepare adhesives, inks, and coatings. Genotoxicity describes the property of any type of DNA damage caused by chemical or physical agents, which may not always result in transmissible mutations. Mutagenicity refers to the induction of permanent transmissible DNA changes (such as DNA composition or chromosome structure) that are retained during somatic cell division and passed on to the offspring of germ cells. Genotoxicity should not be confused with mutagenicity. All mutagens are genotoxic, but not all genotoxic substances are mutagenic.

[0004] The object of the present invention is to provide a compound having at least two aziridinyl groups, which 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 further referred to herein as a polyaziridine compound.

[0005] This object is surprisingly achieved by providing a polyaziridine compound having:

[0006] a) From 2 to less than 6 structural units (A):

[0007]

[0008] where

[0009] m is an integer from 1 to 6; and

[0010] R’ and R” are according to (1) or (2):

[0011] (1) R’ = H or an aliphatic hydrocarbon group having 1 to 14 carbon atoms, and

[0012] R” = H, an aliphatic hydrocarbon group having 1 - 14 carbon atoms, an alicyclic hydrocarbon group having 5 - 12 carbon atoms, an aromatic hydrocarbon group having 6 - 12 carbon atoms,

[0013] CH2 - O - (C = O) - R”’, CH2 - O - R”” or CH2 -

[0014] (OCR””’HCR””’H) n -OR”””, where R”’ is an aliphatic hydrocarbon group having 1 to 14 carbon atoms, R”” is an aliphatic hydrocarbon group having 1 to 14 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, n

[0015] is from 1 to 35, R””’ is independently H or an aliphatic hydrocarbon group having 1 to 14 carbon atoms, and R””” is an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and

[0016] wherein R’ or R” is not H;

[0017] (2) R’ and R” together form a saturated alicyclic hydrocarbon group having 5 to 8 carbon atoms;

[0018] b) One or more linking chains, where each of these linking chains links two of the structural units A; and

[0019] c) A molecular weight in the range of 840 daltons to 5000 daltons.

[0020] Surprisingly, it has been found that, compared to trimethylolpropane tris(2 - methyl - 1 - aziridinepropionate), the polyaziridine compounds of the present invention have reduced genotoxicity. The polyaziridine compounds according to the present invention only show a weakly positive induced genotoxicity, or even they do not show genotoxicity, i.e., they show a genotoxicity level comparable to the naturally occurring background.

[0021] Genotoxicity can be measured by the assay (Toxys, Leiden, Netherlands). The assay can be used for pure substances or for compositions that are compositions of the direct products obtained in the preparation of the polyaziridine compounds of the present invention. Positive induced genotoxicity means that in the absence or presence of a metabolic system of rat S9 liver extract, 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. Weakly positive induced genotoxicity means that in the absence or presence of a metabolic system based on rat S9 liver extract (aroclor1254-induced rats, Moltox, Boone, NC, USA), 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. Genotoxicity equivalent to the naturally occurring background means that in the absence or presence of a metabolic system based on rat S9 liver extract (aroclor1254-induced rats, Moltox, Boone, NC, USA), 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. Substances that show induction levels less than or equal to 1.5-fold 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) are not genotoxic.

[0022] The crosslinking efficiency of the crosslinker can be evaluated by assessing the chemical resistance defined and determined as described below.

[0023] For all upper and / or lower boundaries of any range given herein, unless otherwise specifically indicated, 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.

[0024] In this specification, the term "coating composition" includes paints, coatings, varnishes, adhesives, and ink compositions, but is not limited to this listing. "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 dimethylphenyl and ethyl-substituted phenyl.

[0025] Although the structural unit (A) present in the polyaziridine compound of the present invention may independently have different R', R" and / or m, the structural unit (A) present in the polyaziridine compound is preferably the same as each other.

[0026] The polyaziridine compounds of the present invention are generally obtained in the form of a composition, in which, in addition to the polyaziridine compound, there may be remaining starting materials, by-products and / or solvents in the preparation of the polyaziridine compound. The composition may contain only one polyaziridine compound according to the present invention, but may also contain more than one polyaziridine compound according to the present invention. When a mixture of polyisocyanates is used as the starting material, a mixture of polyaziridine compounds can be obtained, for example.

[0027] The urethane aziridine compound according to the present invention 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.

[0028] Preferably, R' and R" are according to (1) or (2):

[0029] (1) R' = H or an alkyl group containing 1 to 14 carbon atoms, preferably 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and

[0030] R" = H, an aliphatic hydrocarbon group containing 1 to 4 carbon atoms, CH2-O-(C=O)-

[0031] R"', CH2-O-R"" or CH2-(OCR"'HCR"'H) n -OR""", where R"' is an alkyl group containing 1 to 14 carbon atoms, preferably an alkyl group containing 3 to 12 carbon atoms, more preferably a branched alkyl group containing 3 to 12 carbon atoms, such as neopentyl or neodecyl, most preferably R"' is a branched C9 alkyl group, and R"" is an alkyl group containing 1 to 14 carbon atoms, such as ethyl, butyl, 2-ethylhexyl, n is from 1 to 35, preferably n is from 6 to 20, R""" is independently H or methyl, and R"""" is an alkyl group containing 1 to 4 carbon atoms, and

[0032] wherein R' or R" is not H;

[0033] (2) R' and R" form part of a saturated alicyclic hydrocarbon group containing 5 to 8 carbon atoms.

[0034] More preferably, R' = H and R'' = an aliphatic hydrocarbon group having 1 to 14 carbon atoms, an alicyclic hydrocarbon group having 5 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 12 carbon atoms, CH2-O-(C=O)-R''', CH2-O-R'', or CH2-(OCR'''HCR'''H) n -OR'''', where R''' is an aliphatic hydrocarbon group having 1 to 14 carbon atoms, R'' is an aliphatic hydrocarbon group having 1 to 14 carbon atoms or an aromatic group having 6 to 12 carbon atoms, n is from 1 to 35, R''' is independently H or an aliphatic hydrocarbon group having 1 to 14 carbon atoms, and R'''' is an aliphatic hydrocarbon group having 1 to 4 carbon atoms. More preferably, R' is H and R'' = an alkyl group having 1 to 4 carbon atoms, CH2-O-(C=O)-R''', CH2-O-R'', or CH2-(OCH2CH2) n -OCH3, where R'' is an alkyl group having 3 - 12 carbon atoms, R'' is an alkyl group having 1 - 14 carbon atoms. More preferably, R' is H and R'' = an alkyl group having 1 to 4 carbon atoms, CH2-O-(C=O)-R''', CH2-O-R'', or CH2-(OCH2CH2) n -OCH3 where R''' is preferably an alkyl group having 3 to 12 carbon atoms, more preferably a branched alkyl group having 3 to 12 carbon atoms, such as neopentyl or neodecyl. Most preferably, R''' is a branched C9 alkyl group. R'' is preferably an alkyl group having 2 to 14 carbon atoms. Non-limiting examples of R'' are butyl and 2-ethylhexyl.

[0035] The molecular weight of the polyaziridine compound according to the present invention is from 840 to 5000 daltons. The molecular weight of the polyaziridine compound according to the present invention 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 1400 daltons. The molecular weight of the polyaziridine compound according to the present invention 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 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 starting materials for preparing the polyaziridine compound are mixtures, the molecular weight calculation can be performed for each compound present separately in the composition. The molecular weight of the polyaziridine compound according to the present invention can be measured using MALDI-TOF mass spectrometry as described in the experimental section below.

[0036] The polyaziridine compound according to the invention comprises one or more linking chains, where each of these linking chains links two in the 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 covalently linked set of atoms consisting of i) carbon atoms, ii) carbon and nitrogen atoms, or iii) carbon, oxygen, and nitrogen atoms.

[0037] The linking chain is defined as the shortest chain of consecutive atoms that links two structural units A. For an example of the polyaziridine compound according to the invention, the following figure shows the linking chain between two structural units A.

[0038]

[0039] Any two structural units A present in the polyaziridine compound of the invention are linked by a linking chain as defined herein. Thus, each structural unit A present in the polyaziridine compound of the invention is linked to each other structural unit A by a linking chain as defined herein. In the case where the polyaziridine compound according to the invention has two structural units A, the polyaziridine compound has one such linking chain that links these two structural units. In the case where the polyaziridine compound according to the invention has three structural units A, the polyaziridine compound has three linking chains, where each of the three linking chains links one structural unit A to another structural unit A, i.e., the first structural unit A is linked to the second structural unit A by a linking chain, and both the first and second structural units A are independently linked to the third structural unit A by their respective linking chains.

[0040] The following figure shows 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.

[0041]

[0042] The polyaziridine compound according to the invention having more than two structural units A has a plurality of linking chains according to the following equation:

[0043] LC = {(AN - 1) x AN)} / 2, where LC = the number of linking chains and AN = the number of structural units A in the polyaziridine compound. So for example if there are 5 structural units A in the polyaziridine compound, then AN = 5; this means there are {(5 - 1) x 5} / 2 = 10 linking chains.

[0044] 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 present in the linking chain or the N atom of the carbamate group in another structural unit A is at most 9, as shown by the polyaziridine compounds of the present invention below.

[0045]

[0046] The polyaziridine compound preferably contains one or more linking groups, where each linking group connects two structural units A, and where each linking group includes at least one functional group selected from the following: 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, ether functional groups, ester functional groups, amide functional groups, carbonate functional groups, carbamate functional groups, urea functional groups, biuret functional groups, urethane functional groups, uredione functional groups, and any combination thereof. More preferably, the linking group is a series of consecutive functional groups, where each functional group is selected from 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, ether functional groups, ester functional groups, amide functional groups, carbonate functional groups, carbamate functional groups, urea functional groups, biuret functional groups, urethane functional groups, uredione functional groups.

[0047] The figure below shows the linking group of an example of a polyaziridine compound according to the present invention. In this example, the linking group connecting two structural units A consists of the following group of consecutive functional groups: aliphatic hydrocarbon functional group 1 (linear C6H 12 ), isocyanurate functional group 2 (cyclic C3N3O3), and aliphatic hydrocarbon functional group 3 (linear C6H 12 ).

[0048]

[0049] The figure below shows in bold the linking group of the following example of a polyaziridine compound of the present invention. In this example, the linking group connecting two structural units A is the following group of consecutive functional groups: aliphatic hydrocarbon functional group 1 (linear C6H 12 ), isocyanurate 2 (cyclic C3N3O3), and aliphatic hydrocarbon functional group 3 (linear C6H 12 ).

[0050]

[0051] Any two structural units A present in the polyaziridine compound of the present invention are preferably connected by a linking group as defined herein. Thus, each structural unit A present in the polyaziridine compound of the present invention is preferably connected to each other structural unit A by 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 to connect 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, where each of the three linking groups connects one structural unit A to another structural unit A.

[0052] The following figure shows an example of a polyaziridine compound having, for example, three structural units A (three linking groups), where each of the three linking groups connects two structural units A. One linking group consists of the following group of consecutive functional groups: aliphatic hydrocarbon functional group 1 (linear C6H 12 ), isocyanurate 2 (cyclic C3N3O3), and aliphatic hydrocarbon functional group 3 (linear C6H 12 ) to connect the structural units A labeled A1 and A2. For the connection between the structural units A labeled A1 and A3, the linking group consists of the following group of consecutive functional groups: aliphatic hydrocarbon functional group 1 (linear C6H 12 ), isocyanurate 2 (cyclic C3N3O3), and aliphatic hydrocarbon functional group 4 (linear C6H 12 ), while for the connection between the structural units A labeled A2 and A3, the linking group consists of the following group of consecutive functional groups: aliphatic hydrocarbon functional group 3 (linear C6H 12 ), isocyanurate 2 (cyclic C3N3O3), and aliphatic hydrocarbon functional group 4 (linear C6H 12 ).

[0053]

[0054] Preferably, the linking group includes at least one functional group selected from aliphatic hydrocarbon functional groups (preferably having 1 to 8 carbon atoms), alicyclic hydrocarbon functional groups (preferably having 4 to 10 carbon atoms), aromatic hydrocarbon functional groups (preferably having 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 and a hybrid isocyanurate such as HDI / IPDI isocyanurate, resulting in a polyaziridine compound having a linking group composed of an array of consecutive functional groups: linear C6H 12 (i.e., an aliphatic hydrocarbon functional group having 6 carbon atoms), an isocyanurate functional group (cyclic C3N3O3), and

[0055]

[0056] (i.e., an alicyclic hydrocarbon functional group having 9 carbon atoms and an aliphatic hydrocarbon functional group having 1 carbon atom).

[0057] The term "aliphatic hydrocarbon functional group" refers to an optionally branched alkyl, alkenyl, and alkynyl group. Although the optional branches 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 a cycloalkyl and cycloalkenyl group optionally substituted by at least one aliphatic hydrocarbon group. Although the optional aliphatic hydrocarbon group substituent is part of the linking group, it is not part of the linking chain. The optional aliphatic hydrocarbon group substituent is preferably an alkyl group. 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 substituent is preferably an alkyl group. Although the optional aliphatic hydrocarbon group substituent is part of the linking group, it is not part of the linking chain.

[0058] On the linking group, one or more substituents can be present as side groups on the linking group, for example, shown in bold in the following polyaziridine compounds. These side groups do not belong to the linking group.

[0059]

[0060] The side group preferably contains wherein X, R7, R8, n', and R 10As described below. In one embodiment of the present invention, the polyaziridine compound contains one or more linking groups, wherein each of these linking groups connects two in structural unit A, and the linking group is composed 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 the side groups have the following structural formula:

[0061]

[0062] 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.

[0063] X is O or NH, preferably X is O,

[0064] R7 and R8 are independently H or CH3 in each repeating unit,

[0065] R9 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

[0066] R 10 contains at most 20 carbon atoms and is an aliphatic, alicyclic or aromatic hydrocarbon group or a combination thereof. In a preferred embodiment, one of R7 and R8 is H and the other R7 or R8 is CH3. In another more preferred embodiment, R7 and R8 are H. R 10 is preferably an aliphatic hydrocarbon group containing 1 to 20 carbon atoms (preferably CH3), an alicyclic hydrocarbon group containing 5 to 20 carbon atoms or an aromatic hydrocarbon group containing 6 to 20 carbon atoms. The presence of the side groups results in a decrease in the viscosity of the polyaziridine compound, and thus it is more easily miscible with the polymer to be crosslinked. In this embodiment, the polyaziridine compound preferably contains 2 structural units A. In this embodiment, the linking group is preferably composed of the following group of consecutive functional groups: a first cycloaliphatic hydrocarbon functional group, an isocyanurate functional group or an iminooxadiazinedione functional group, and a second cycloaliphatic hydrocarbon functional group, and R9 is a cycloaliphatic hydrocarbon group, wherein the first cycloaliphatic hydrocarbon functional group and the second cycloaliphatic hydrocarbon functional group are the same as R9, more preferably the linking group is composed of the following group of 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 R9 is an aliphatic hydrocarbon group, wherein the first cycloaliphatic hydrocarbon functional group and the second aliphatic hydrocarbon functional group are the same as R9.

[0067] In a preferred embodiment, the polyaziridine compound according to the present invention contains a polyoxyethylene (-O-CH2-CH2-) x group and / or a polyoxypropylene (-O-CHCH3-CH2-) xa group, the amount of the group is preferably at least 0.1% by weight, more preferably at least 6% by weight, still more preferably at least 10% by weight, preferably less than 45% by weight, more preferably less than 25% by weight and most preferably less than 16% by weight relative to the amount of the polyaziridine compound. Preferably, the polyaziridine compound contains polyoxyethylene (-O-CH2-CH2-) x a group, preferably at least 0.1% by weight, more preferably at least 6% by weight, still more preferably at least 10% by weight, preferably less than 45% by weight, more preferably less than 25% by weight, most preferably less than 16% by weight relative to the content of the polyaziridine compound. Containing polyoxyethylene (-O-CH2-CH2-) x The polyaziridine compound containing the group 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 with an isocyanate and an alkoxypoly(ethylene glycol) and / or poly(ethylene glycol). Compound B has the following structural formula:

[0068]

[0069] 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 resulting compound with compound (B). The reaction product can also be obtained by reacting compound B with a polyisocyanate and reacting the resulting compound 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, still 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 of a diol polyol, the OH functionality is 2. The equivalent weight of the polyol is calculated by dividing 56100 by the OH number 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.

[0070] The isocyanurate functional group is defined as

[0071] The iminooxadiazinedione functional group is defined as

[0072] The urethane functional group is defined as

[0073] The uredione functional group is defined as

[0074] The biuret functional group is defined as

[0075] In a preferred embodiment of the present invention, the linking group present in the polyaziridine compound of the present invention 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 iminooxadiazinedione functional group or a urethane functional group or a uredione functional group and (iii) optionally at least one aromatic hydrocarbon functional group. Preferably, the linking group present in the polyaziridine compound of the present invention 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 iminooxadiazinedione functional group and (iii) optionally at least one aromatic hydrocarbon functional group. A very suitable method for obtaining such a polyaziridine compound is to react compound B with a polyisocyanate compound having aliphatic reactivity, and compound B has the following structural formula:

[0076]

[0077] The term "aliphatically reactive polyisocyanate" is intended to denote compounds in which all isocyanate groups are bonded directly to aliphatic or cycloaliphatic hydrocarbon radicals, regardless of whether aromatic hydrocarbon radicals are also present. The aliphatically reactive polyisocyanate can be a mixture of aliphatically reactive polyisocyanates. Compounds based on aliphatically reactive polyisocyanates have a reduced tendency to yellow over time compared to similar compounds based on aromatically reactive polyisocyanates. The term "aromaticaly reactive polyisocyanate" is intended to denote compounds in which all isocyanate groups are bonded directly to benzene or naphthalene groups, whether or not aliphatic or cycloaliphatic groups are also present. Preferred aliphatically 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 their isocyanurates or iminooxadiazinediones. More preferred aliphatically 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, the linking group preferably consists of the following consecutive functional groups: aliphatic hydrocarbon functional groups, aromatic hydrocarbon functional groups and aliphatic hydrocarbon functional groups (e.g. when preparing polyaziridine compounds using TMXDI), or the linking group consists of the following consecutive functional groups: cycloaliphatic hydrocarbon functional groups, aliphatic hydrocarbon functional groups and cycloaliphatic hydrocarbon functional groups (e.g. when preparing polyaziridine compounds using H12MDI), or more preferably, the linking group consists of the following consecutive functional groups: aliphatic hydrocarbon functional groups, isocyanurate functional groups or iminooxadiazinedione functional groups and aliphatic hydrocarbon functional groups. Most preferably, in this embodiment, the linking group consists of an array of the following consecutive functional groups: aliphatic hydrocarbon functional groups, isocyanurate functional groups and aliphatic hydrocarbon functional groups (e.g. when using the isocyanurate of 1,6-hexamethylene diisocyanate and / or the isocyanurate of 1,5-pentamethylene diisocyanate for preparing polyaziridine compounds).

[0078] The polyaziridine compound according to the present invention 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 polyaziridine compound according to the present invention preferably has an aziridine equivalent weight (the molecular weight of the polyaziridine compound divided by the number of aziridine groups present in the polyaziridine compound) of at least 250 daltons, more preferably at least 280 daltons, even more preferably at least 320 daltons, preferably at most 2500 daltons, more preferably at most 1000 daltons, even more preferably at most 500 daltons.

[0079] 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-ethylmorpholine, dimethylbenzylamine, and triethylamine. Alternatively, alkali metal hydroxides such as NaOH, LiOH, KOH, and combinations of amines and alkali metal hydroxides can be used.

[0080] The polyaziridine compound according to the present invention is preferably obtained by reacting at least one polyisocyanate with a compound B having the following structural formula:

[0081]

[0082] wherein R’, R” and m and their preferred definitions are as above, wherein the molar ratio of compound B to the polyisocyanate is from 2 to 6, more preferably from 2.1 to 5, most preferably from 2.4 to 3. Most preferably, m = 1. 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 in the presence of, for example, a tin catalyst such as dibutyltin dilaurate or a bismuth catalyst such as bismuth neodecanoate at a temperature in the range of 0 to 110 °C, more suitably 20 to 110 °C, more suitably 40 °C to 95 °C, and even more suitably 60 to 85 °C. Solvents such as dimethylformamide DMF, acetone and / or methyl ethyl ketone can be used. 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 a raw material. Preferred polyisocyanates are polyisocyanates having aliphatic reactivity. The term "polyisocyanate having aliphatic reactivity" is intended to mean 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 iminooxadiazinedione trimer containing HDI is N3900, available from Covestro. A suitable urethane containing HDI is XP2860, available from Covestro. A suitable uretidione containing HDI is N3400, available from Covestro. 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 ( HT2500 / LV) and Tosoh ( HXRLV). Methods for preparing compound (B) and derivatives are known in the art. For example, the synthesis of 1-(aziridin-1-yl)propan-2-ol is described by A. Baklien, M. V. Leeding, J. Kolm Aust. J. Chem. 1968, 21, 1557-1570.

[0083] Compound B is preferably obtained by reacting at least one non-OH-functional monocyclic epoxide compound with ethyleneimine. The non-OH-functional monocyclic epoxide can be a mixture of different non-OH-functional monocyclic epoxides. Non-limiting examples of non-OH-functional monocyclic epoxides are propylene oxide, 2-ethyloxirane, n-butyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, 4-tert-butylphenyl 2,3-epoxypropyl ether (= tert-butylphenyl glycidyl ether), cresyl glycidyl ether (ortho or para) and glycidyl neodecanoate. The non-OH-functional monocyclic epoxide is preferably selected from propylene oxide (CAS No. 75-56-9), 2-ethyloxirane (CAS No. 106-88-7), n-butyl glycidyl ether (CAS No. 2426-08-6), 2-ethylhexyl glycidyl ether (CAS No. 2461-15-6), glycidyl neodecanoate (CAS No. 26761-45-5) and any mixture thereof. More preferably, the non-OH-functional monocyclic epoxide is selected from propylene oxide (CAS No. 75-56-9), 2-ethyloxirane (CAS No. 106-88-7), n-butyl glycidyl ether (CAS No. 2426-08-6), 2-ethylhexyl glycidyl ether (CAS No. 2461-15-6), glycidyl neodecanoate (CAS No. 26761-45-5) and any mixture thereof. Most preferably, the non-OH-functional monocyclic epoxide compound is selected from n-butyl glycidyl ether, 2-ethylhexyl glycidyl ether, glycidyl neodecanoate and any mixture thereof.

[0084] The polyaziridine compound according to the present invention is preferably obtained by a method comprising at least the following steps (i) and (ii):

[0085] (i) Reacting ethyleneimine with at least one non-OH-functional monocyclic epoxide compound to obtain compound B, and

[0086] (ii) React compound B with a polyisocyanate.

[0087] Step (i) can be carried out, for example, by bringing 1 equivalent of an epoxide into contact with 1 equivalent of aziridine at atmospheric pressure at a temperature of from -10°C to 60°C, more suitably from -5°C to 50°C, and even more suitably from 0°C to 40°C. The reaction of the adduct (compound (B)) obtained in step (i) with a polyisocyanate (step (ii)) can be carried out, for example, by bringing an equal amount of polyisocyanate into contact with the adduct at atmospheric pressure at a temperature of from 20°C to 110°C, more suitably from 40°C to 95°C, in the presence of a tin catalyst such as dibutyltin dilaurate.

[0088] Examples of preferred polyaziridine compounds according to the invention are

[0089]

[0090]

[0091] Another aspect of the invention is a crosslinking agent composition which comprises at least one polyaziridine compound as defined above and further comprises at least one additional component, such as the remaining starting materials, by-products and / or solvents used for the preparation of said compound. The crosslinking agent composition according to the invention may comprise only one polyaziridine compound according to the invention, but may also comprise more than one polyaziridine compound according to the invention. For example, when a mixture of polyisocyanates is used as a starting material for the preparation of polyaziridines, a mixture of polyaziridine compounds is obtained. After obtaining the polyaziridine compounds according to the invention, the polyaziridine compounds according to the invention can be separated, the reaction products can be used without further purification, or the solvents used for the preparation of the polyaziridine compounds according to the invention can be removed from the composition obtained from the preparation of the polyaziridine compounds according to the invention. The amount of the polyaziridine compounds according to the invention in the crosslinking agent composition is generally at least 10% by weight, usually at least 15% by weight and most usually at least 25% by weight, based on the total amount of the composition. The amount of the polyaziridine compounds according to the invention in the crosslinking agent composition is preferably at least 60% by weight, more preferably at least 80% by weight and most preferably at least 99% by weight, based on the total amount of the composition. The molecular weight of the polyaziridine compounds in the crosslinking agent composition is in the range of from 840 daltons to 5000 daltons. The preferred molecular weight is as described above, and the molecular weight of the polyaziridine compounds is determined by 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.

[0092] The amount of aziridine-functional molecules having a molecular weight lower than 250 Daltons, more preferably lower than 350 Daltons, even more preferably lower than 450 Daltons, even more preferably lower than 550 Daltons, and even more preferably lower than 820 Daltons, present in the crosslinking agent composition according to the invention, is preferably lower than 1.5% by weight, more preferably lower than 1% by weight, more preferably lower than 0.5% by weight, and most preferably lower than 0.1% by weight, relative to the total weight of the crosslinking agent composition, where the molecular weight is determined using LC-MS as described in the experimental section below.

[0093] The average number of aziridine groups having the structural formula (C) per aziridine-group-containing molecule in the crosslinking agent composition is preferably at least 1.8, more preferably at least 2, more preferably at least 2.2, and preferably less than 10, more preferably less than 6, and most preferably less than 4,

[0094]

[0095] Most preferably, the average number of aziridine groups having the structural formula (C) per aziridine-group-containing molecule in the 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 of urethane bonds, relative to the total weight of the polyaziridine compound according to the invention present in the crosslinking agent composition.

[0096] In view of the potential water sensitivity of the polyaziridine compound according to the invention, the crosslinking agent composition preferably contains no substantial amount of water, more preferably no water. Containing no substantial 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 according to the invention, 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 invention).

[0097] The polyaziridine compound according to the 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 ISO 2555-89. In an alternative embodiment, the viscosity of the polyaziridine is measured with a Brookfield with rotor S63 at 25 °C in a solution of 80% solids in dimethylformamide (DMF). The viscosity measured according to this method is preferably in the range of 300 to 20,000 mPas, more preferably in the range of 500 to 12,000 mPas, most preferably in the range of 700 to 3000 mPas.

[0098] The polyaziridine compound according to the invention or a crosslinking agent composition comprising at least one polyaziridine compound as defined above can advantageously be used as a crosslinking agent for crosslinking carboxylic acid functional polymers dissolved and / or dispersed, preferably dispersed, in an aqueous solution.

[0099] Another aspect of the invention is a two-component coating system which comprises a first component and a second component, 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 comprises a polyaziridine compound as defined above or wherein the second component is a crosslinking agent composition as defined above, wherein the first and second components are stored separately because the crosslinking reaction of the crosslinking agent with the polymer to be crosslinked may start immediately after mixing the aqueous compositions of the crosslinking agent and the polymer to be crosslinked. Immediately before applying the coating composition, the first component and the second component of the two-component system are mixed to obtain a coating composition comprising aziridine groups Q and carboxylic acid groups. Before mixing 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, even more preferably at least 8.5.

[0100] The carboxylic acid functional polymer present in the first component of the two-component coating system contains carboxylic acid groups and / or carboxylic acid ester groups, which preferably do not contain covalent bonds that prevent the chemical reaction of these groups 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., the carboxylic acid functional polymer. Thus, the amount of carboxylic acid groups present in the carboxylic acid functional polymer is the total amount of carboxylic acid ester groups and carboxylic acid groups present in the carboxylic acid functional polymer. The polymer to be crosslinked preferably contains at least partially base-neutralized carboxylic acid groups. Preferably, at least part of the base is a volatile base. Preferably, at least a part of the carboxylic acid groups present in the carboxylic acid functional polymer to be crosslinked is deprotonated to obtain carboxylic acid 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 were described above. The preferred base is a tertiary amine. Preferred tertiary amines are as described above. Most preferred is triethylamine.

[0101] Non-limiting examples of crosslinkable carboxylic acid-functional polymers are vinyl polymers such as styrene-acrylics, (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 functional group. The carboxylic acid-functional polymer is preferably selected from polyesters, polycarbonates, polyamides, vinyl polymers, polyacrylates, polymethacrylates, poly(acrylate-co-methacrylate), polyurethanes, poly(urethane-co-acrylate), poly(urethane-co-methacrylate), poly(urethane-co-acrylate-co-methacrylate), polyureas, and mixtures thereof. Preferably, the vinyl polymer refers to a polymer containing reaction residues of styrene and acrylate and / or methacrylate. In one embodiment of the present invention, the preferred crosslinkable carboxylic acid-functional polymer is selected from vinyl polymers, polyacrylates, polymethacrylates, poly(acrylate-co-methacrylate), and mixtures thereof. In another embodiment, the carboxylic acid-functional polymer is selected from polyurethanes, poly(urethane-co-acrylate), poly(urethane-co-methacrylate), poly(urethane-co-acrylate-co-methacrylate), polyureas, and mixtures thereof. The present invention also relates to a coating composition obtained by mixing a first component and a second component of a two-component coating system immediately before applying the coating composition, wherein the coating composition contains aziridine groups Q and carboxylic acid groups, and the amounts of the aziridine groups Q and carboxylic acid groups are such that the stoichiometric amount (SA) of aziridine group Q on the carboxylic acid group is preferably from 0.1 to 2.0, more preferably from 0.2 to 1.5, further 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, still more preferably at least 8.5, and even more preferably at least 9.

[0102] The present invention also relates to a substrate having a coating, which is obtained by (i) applying the coating composition as described above to the substrate and (ii) drying the coating composition by evaporation of 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 of 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, and glass fiber reinforcements. The thickness of the dry coating on the substrate is preferably 1 - 200 μm, more preferably 5 - 150 μm, and most preferably 15 - 90 μm. In the case where the coating composition is an ink composition, the thickness of the dry ink is preferably 0.005 to 35 μm, more preferably 0.05 to 25 μm, and most preferably 4 to 15 μm.

[0103] The present invention will now be illustrated by reference to the following examples. Unless otherwise stated, all parts, percentages, and ratios are by weight.

[0104] AV determination

[0105] The solid acid value (AV) of the sample was determined according to standard ASTM D1639 - 90(1996)e1. In this process, the sample dissolved in a good solvent was titrated with an alcoholic potassium hydroxide solution of known concentration (KOH). The difference in the titration volume between the sample and the blank was a measure of the solid acid value, according to the following formula: AV = [(Vblank – Vsample)*N KOH *56.1] / (W*S / 100), where AV is the solid acid value in mg KOH / g of 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 KOH is the normality of the KOH solution, W is the sample weight in grams, and S is the solid content of the sample in %. The measurement was repeated twice using a potentiometric end point on a Metrohm 702SM Titrino titrator (the measurement was accepted if the difference between the two results was < 0.1 mg KOH / g of solid material).

[0106] Chemical resistance

[0107] Chemical resistance test based on standard DIN 68861 - 1:2011 - 01.

[0108] Unless otherwise stated, the chemical resistance test was as follows:

[0109] Compared to the carboxylic acid functional group, the coating composition consists of 0.9 stoichiometry (SA) of total carboxylic acid-reactive functional groups (e.g., aziridine). The coating composition is treated 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 1:1 ethanol:softened water (by weight) and placed on the film for 60 minutes (unless otherwise stated). The absorbent cotton is removed and the film is left overnight. After that, the spots are scored according to the following grades:

[0110] 1 The coating is completely degraded;

[0111] 2 The coating structure is damaged;

[0112] 3 Severe marks on the coating, visible from multiple directions;

[0113] 4 Slight marks on the coating, visible from a specific angle;

[0114] 5 No marks or gloss changes are observed.

[0115] Viscosity measurement:

[0116] The apparent viscosity is determined according to ISO 2555:2018. The measurement is carried out at 23 °C on a Brookfield DVE-LV viscometer (single cylinder geometry) at 60 rpm. The rotor is selected from S62, S63 or S64, and the smallest numbered rotor (i.e., the largest rotor) that produces 10% and 100% torque readings is used.

[0117] Low molecular weight fraction of LC-MS

[0118] LC system: Agilent 1290 Infinity II; Detector #1: Agilent 1290 Infinity IIPDA; Detector #2: Agilent iFunnel 6550 Q-TOF-MS.

[0119] The following procedure is used for LC-MS analysis of the low molecular weight fraction. A solution of ~100 mg / kg substance is prepared gravimetrically in methanol and stirred. 0.5 μl of this solution is injected into a UPLC equipped with an ESI-TOF-MS detector. The column used is 100 x 2.1 mm, 1.8 um, Waters HSS T3 C18, operating at 40 °C. The flow rate is 0.5 ml.min -1。The solvents used were 10 mM NH4CH3COO aqueous solution (eluent A) adjusted to pH 9.0 with NH3, acetonitrile (B), and THF (C). Two binary gradients were applied, from 80 / 20 A / B to 1 / 99 A / B in 10 minutes and from 1 / 99 A / B to 1 / 49 / 50 A / B / C in 5 minutes, followed by the starting condition (80 / 20 A / B). Assuming that all components have a linear MS response over all response ranges and that the ionization efficiency of all components is the same, the total ion current signal was integrated. In the case of co-elution, the extracted ion chromatogram of that particular species was integrated. The integrated signal of a specific low molecular weight peak was divided by the total integrated sample signal to obtain the fraction of that low molecular weight substance.

[0120] MALDI-ToF-MS

[0121] All MALDI-ToF-MS spectra were obtained using a Bruker Ultraflextreme MALDI-ToF mass spectrometer. The instrument was equipped with a Nd:YAG laser with an emission wavelength of 1064 nm and a collision cell (not used for these samples). Spectra were acquired in positive ion mode using the reflector and 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 a concentration of 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.

[0122] Sodium iodide was used as the salt (NaI, CAS number 7681-82-5); 10 mg was dissolved in 1 ml of THF and 1 drop of MeOH was added. The ratio of sample:matrix:salt was 10:200:10 (μl). After mixing, 0.5 μL was spotted on the MALDI plate and allowed to air dry. The peaks measured in the MALDI spectrum were the sodium adducts of the polyaziridine compounds. 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-TOFMS peak and M 阳离子 is the accurate mass of the cation used to form the adduct (in this case, the M of sodium 阳离子= 23.0 Da). The polyaziridine compounds 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), with a maximum deviation of 0.6 Da.

[0123] Synthesis of Aqueous Polyurethane P1

[0124] Charge a 1 L flask (equipped with a thermometer and an overhead stirrer) with 29.9 g of dimethylolpropionic acid, 282.1 g of polypropylene glycol (calculated average molecular weight (M) of 2000 Da, OH value of 56 ± 2 mg KOH / g of polypropylene glycol), 166.5 g of polypropylene glycol (calculated average molecular weight (M) of 1000 Da, OH value of 112 ± 2 mg KOH / g of polypropylene glycol), and 262.8 g of isophorone diisocyanate (the average molecular weight of each polyol is calculated from its OH value according to the formula: M = 2 * 56100 / [OH-value, mg KOH / g of polypropylene glycol). Place the reaction mixture under an N2 atmosphere and heat it to 50 °C, and then add 0.07 g of dibutyltin dilaurate to the reaction mixture. An exothermic reaction is observed; however, appropriate measures are taken to keep the reaction temperature from exceeding 97 °C. The reaction is maintained at 95 °C for 1 hour. The NCO content of the resulting polyurethane P1’ is determined to be 7.00% (theoretical value is 7.44%) according to ISO 14896 Method A (2009), and the acid value of polyurethane P1’ is 16.1 ± 1 mg KOH / g of polyurethane P1’. Cool the polyurethane P1’ to 60 °C and add 18.7 g of triethylamine, and stir the resulting mixture for 30 minutes. Subsequently, the aqueous dispersion of polyurethane P1’ (the aqueous dispersion of polyurethane P1’ is further referred to as P1) is prepared as follows: Add the mixture of the thus-prepared polyurethane P1’ and triethylamine to a mixture of 1100 g of softened 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 is completed, stir the mixture for another 5 minutes, and then add 111.2 g of hydrazine (16 wt% aqueous solution) to the mixture. Stir the aqueous dispersion of the thus-prepared polyurethane P1’ for another 1 hour to obtain P1.

[0125] Genotoxicity testing

[0126] By the assay (Toxys, Leiden, the Netherlands) evaluate the genotoxicity of the examples and comparative examples. The ToxTracker assay is a set of validated green fluorescent protein (GFP)-based mouse embryonic stem (mES) reporter cell lines that can be used to identify the biological reactivity and potential carcinogenic properties of newly developed compounds in a single test. This method uses a two-step approach.

[0127] 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.

[0128] Next, the genotoxicity of the examples and comparative examples of DNA damage was evaluated using specific genes related to the reporter gene; namely, the Bscl2 (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 in 96-well cell culture plates. Twenty-four hours after seeding the cells in the 96-well plates, fresh ES cell medium containing the diluted test article was added to the cells. For each compound tested, five concentrations were tested at two-fold dilutions. The highest sample concentration caused significant cytotoxicity (50 - 70%). In the absence or low cytotoxicity, 10 mM or the maximum soluble mixture concentration was used as the maximum test concentration. Cytotoxicity was determined by cell counting after 24 hours of exposure using a Guava easyCyte 10HT flow cytometer (Millipore).

[0129] Induction of the GFP reporter gene was always compared to a vector control treatment. For a given compound, the DMSO concentration was similar in all wells and never exceeded 1%. All compounds were tested in at least 3 completely independent replicates. All experiments included a positive reference 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, cells were cultured for 24 h in fresh ES cell medium. Induction of the GFP reporter gene was determined 24 h after exposure 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 for cytotoxicity assessment. Data were analyzed using ToxPlot software (Toxys Leiden the Netherlands). The reported induction levels were the compound concentrations inducing 10%, 25% and 50% cytotoxicity after 3 h exposure and 24 h recovery in the presence of S9 rat liver extract or after 24 h exposure in the absence of S9 rat liver.

[0130] Positive induction levels of biomarkers were 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; negative induction was defined as lower than or equal to 1.5-fold induction at at least one of 10%, 25% and 50% cytotoxicity in the absence and presence of the metabolic system based on rat S9 liver extract.

[0131] Components and Abbreviations Used:

[0132] Dimethylformamide (CAS No. 68-12-2) was purchased from Acros Organics (a division of Thermo Fisher Scientific).

[0133] Di(propylene glycol) dimethyl ether (Proglyde DMM, CAS No. 111109-77-4) was purchased from Dow Inc.

[0134] Trimethylolpropane tris(2-methyl-1-aziridinepropionate), CAS No. 64265-57-2, CX-100 was purchased from DSM.

[0135] Pentaerythritol tris(3-(1-aziridinyl)propionate), CAS No. 57116-45-7, was purchased from ABCR.

[0136] Potassium carbonate (CAS No. 584-08-7) was purchased from Alfa Aesar (a division of Thermo Fisher Scientific).

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

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

[0139] n-Butyl glycidyl ether (CAS No. 2426-08-6) was purchased from Alfa Aesar (a division of Thermo Fisher Scientific).

[0140] N3600 and N3900 were purchased from Covestro.

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

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

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

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

[0145] Ethylenimine (CAS No. 151-56-4) was purchased from Menadiona S.L. (Palafolls, Spain).

[0146] Cardura E10P (CAS No. 26761-45-5), purchased from Hexion Inc.

[0147] H12MDI (4,4'-methylenebis(phenyl isocyanate), W, CAS No. 101-66-8), purchased from Covestro.

[0148] Hydrazine (16% aqueous solution, CAS No. 302-01-2), purchased from Honeywell.

[0149] Dimethylolpropionic acid (DMPA, CAS No. 4767-03-7), purchased from Perstop Polyols.

[0150] Triethylamine (TEA, CAS No. 121-44-8), purchased from Arkema

[0151] 1-Propanol (CAS No. 71-23-8), purchased from Sigma-Aldrich.

[0152] Tin 2-ethylhexanoate (CAS No. 301-10-0), purchased from Sigma-Aldrich.

[0153] Dibutyltin dilaurate (CAS No. 77-58-7), purchased from Sigma-Aldrich.

[0154] D3403, purchased from Evonik.

[0155] Polypropylene glycol, number average molecular weight of 1000 Da and number average molecular weight of 2000 Da, obtained from BASF.

[0156] 3-Methyl-1-phenyl-2-phospha-1-oxide (CAS No. 707-61-9), purchased from Sigma-Aldrich.

[0157] Sodium lauryl sulfate (30% aqueous solution, CAS No. 73296-89-6), purchased from BASF.

[0158] Methyl methacrylate (CAS No. 80-62-6), purchased from Lucite Int.

[0159] n-Butyl acrylate (CAS No. 141-32-2), purchased from Dow Chemical.

[0160] Methacrylic acid (CAS No..79-41-4), purchased from Lucite Int.

[0161] Ammonium persulfate (CAS No. 7727-54-0), purchased from United Initiators.

[0162] Ammonia (25% aqueous solution, CAS No. 1336-21-6), purchased from Merck.

[0163] 1-Butanol (CAS No. 71-36-3), purchased from Sigma-Aldrich.

[0164] Comparative Example 1

[0165] Comparative Example 1 is CX-100, trimethylolpropane tris(2-methyl-1-aziridinepropionate), purchased from DSM. The chemical structure is shown below.

[0166]

[0167] For reference, the performance of trimethylolpropane tris(2-methyl-1-aziridinepropionate) as a crosslinking agent was evaluated by spot tests performed on the coating surface according to the procedure of DIN68861-1:2011-01 standard. For these tests, 0.23 parts of the compound was mixed with 0.60 parts of Proglyde TM DMM (dipropylene glycol dimethyl ether, isomer mixture) and incubated with regular stirring at 80 °C for 10 minutes. Subsequently, 0.56 parts of the resulting solution was added to 20 parts of P1 with continuous stirring, and the resulting mixture was further stirred for 30 minutes. After that, the coating composition was filtered and applied to a Leneta test card (Test C1-1) using a 100 μm wire applicator. The film was dried at 25 °C for 16 hours, then annealed at 50 °C for 1 hour, and then dried at 25 °C for 24 hours. Subsequently, a piece of absorbent cotton was soaked in 1:1 EtOH:softened water and placed on the film for different times. After removing the EtOH and allowing it to recover for 60 minutes, the following results were obtained (1 point indicates complete degradation of the film, 10 points indicates no visible damage):

[0168] Ethanol spot test

[0169]

[0170] Genotoxicity test

[0171]

[0172] The genotoxicity test results showed that the crosslinking agent of Comparative Example 1 was genotoxic.

[0173] Comparative Example 2

[0174] 15.0 g of Desmodur N 3600 and 75 g 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. The mixture was then heated to 50 °C, and 6.80 g of 1-(2-hydroxyethyl)ethylenimine was added. After 15 minutes, 0.03 g of bismuth neodecanoate was charged into the reaction flask, and it was further heated to 60 °C. Samples were taken regularly and the reaction progress was monitored using a Bruker Alpha FT-IR spectrometer until no NCO-stretching was observed at 2200 - 2300 cm -1 No NCO-stretching was observed. The solvent was removed in vacuo to give a clear, slightly yellow, highly viscous liquid. The calculated molecular weight of the theoretical main component was 765.47 Da, and the chemical structure is shown below:

[0175]

[0176] The molecular weight was confirmed by Maldi-TOF-MS: calculated [M+K+] = 804.43 Da; found [M+K+] = 804.27 Da.

[0177] Genotoxicity test

[0178]

[0179] The genotoxicity test results showed that the crosslinking agent of Comparative Example 2 was genotoxic.

[0180] Comparative Example 3

[0181] 2.60 g of 1-(aziridin-1-yl)propan-2-ol, 0.02 g of bismuth neodecanoate and 32 g 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. Then a solution of 5.00 g of Desmodur N 3600 in 32 g of dimethylformamide was added dropwise to the reaction flask over 15 minutes, and the mixture was further heated to 70 °C. Samples were taken regularly and the reaction progress was monitored using a Bruker Alpha FT-IR spectrometer until no NCO-stretching was observed at 2200 - 2300 cm -1 No NCO-stretching was observed. The solvent was removed in vacuo to give an opaque, highly viscous liquid. The calculated molecular weight of the theoretical main component was 807.52 Da, and the chemical structure is shown below:

[0182]

[0183] The molecular weight was confirmed by Maldi-TOF-MS: calculated [M+Na+] = 830.52 Da; found [M+Na+] = 830.47 Da.

[0184] Genotoxicity test

[0185]

[0186] The genotoxicity test results showed that the crosslinking agent of Comparative Example 3 had genotoxicity.

[0187] Example 1

[0188] A round-bottomed flask equipped with a condenser was placed under a N2 atmosphere and charged with etheylene imine (50.0 g), n-butyl glycidyl ether (108.0 g) and K2CO3 (5.00 g) and heated to 40 °C within 30 minutes. Then the mixture was stirred at T = 40 °C for 48 hours. After filtration, the excess EI was removed under vacuum and then further purified by vacuum distillation to obtain a colorless low-viscosity liquid.

[0189] 3.45 g of the obtained material (1-(aziridin-1-yl)-3-butoxypropan-2-ol) was charged into a reaction flask equipped with a thermometer together with 0.02 g of bismuth neodecanoate and 15 g of dimethylformamide. The mixture was stirred with a mechanical stirrer at the upper part under a nitrogen atmosphere and heated to 50 °C. Then 4.00 g of a solution of N 3600 in 8 g of dimethylformamide was added dropwise to the reaction flask over 45 minutes while maintaining the reaction temperature constant at 50 °C. Samples were taken regularly and the reaction progress was monitored using a BrukerAlpha FT-IR spectrometer until no change in the NCO-stretching was observed at 2200 - 2300 cm -1 Subsequently, 0.13 g of 1-butanol was added to the mixture and the reaction was further continued until the above-mentioned NCO-stretching peak completely disappeared. The solution was concentrated in vacuo to a 25 wt% solution, yielding a slightly viscous liquid.

[0190] The calculated theoretical molecular weight of the main component was 1023.69 Da and the chemical structure was as shown below:

[0191]

[0192] The molecular weight was confirmed by Maldi-TOF-MS: calculated value [M+Na+] = 1046.69 Da; measured value [M+Na+] = 1046.72 Da.

[0193] The following components with a mass below 840 Da were determined and quantified by LC-MS:

[0194] The amount present in the composition was 0.48 wt% and

[0195] the amount present was below 0.01 wt%.

[0196] According to the procedure of standard DIN 68861-1:2011-01, the performance of the synthetic compound as a crosslinking agent was evaluated using a dot test on the coated surface. For these tests, 1.4 parts of the crosslinking agent solution were added to 10 parts of P1 with continuous stirring, and the resulting mixture was further stirred for 30 minutes. After that, 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 without 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 then dried at 25 °C for 24 hours. Subsequently, a piece of absorbent cotton was soaked in 1:1 EtOH:softened water and placed on the film for different times. After removing the EtOH and allowing it to recover for 60 minutes, the following results were obtained (1 point indicates complete degradation of the film, and 5 points indicates no visible damage):

[0197] Ethanol dot test

[0198]

[0199] Genotoxicity test

[0200]

[0201] The genotoxicity test results showed that the crosslinking agent composition of Example 1 was non-genotoxic.

[0202] Comparative Example 4:

[0203] 1.00 g of 4,4'-methylenebis(cyclohexyl isocyanate) and 4.8 g 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. 0.02 g of bismuth neodecanoate was added to the solution. Then, a solution of 1.21 g of 1-(aziridin-1-yl)-3-butoxypropan-2-ol in 2.28 g of dimethylformamide was added dropwise to the reaction flask over 15 minutes, and then the mixture was further heated to 80 °C. Samples were taken regularly and the reaction progress was monitored using a Bruker Alpha FT-IR spectrometer until no change in the NCO-stretching was observed at 2200 - 2300 cm -1 Subsequently, 0.05 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 evaporated under vacuum to obtain a highly viscous opaque liquid. The calculated theoretical molecular weight of the main component was 608.45 Da, and the chemical structure is shown below:

[0204]

[0205] The molecular weight was confirmed by Maldi-TOF-MS: calculated value [M+Na+] = 631.45 Da; measured value [M+Na+] = 631.45 Da.

[0206] Genotoxicity test

[0207]

[0208] The genotoxicity test results showed that the crosslinking agent composition of Comparative Example 4 had genotoxicity.

[0209] Example 2

[0210] A round-bottomed flask equipped with a condenser was placed under a N2 atmosphere and charged with ethyleneimine (50.0 g), n-butyl glycidyl ether (108.0 g), and K2CO3 (5.00 g) and heated to 40 °C within 30 minutes. Then the mixture was stirred at T = 40 °C for 48 hours. After filtration, the excess EI was removed under vacuum, and then further purified by vacuum distillation to obtain a colorless low-viscosity liquid.

[0211] 0.67 g of the obtained material (1-(aziridin-1-yl)-3-butoxypropan-2-ol), 0.54 g of poly(ethylene glycol) monomethyl ether with an average Mn of 500 Da, and 2.28 g of dimethylformamide were charged into a feed funnel. The mixture was added to a reaction flask equipped with a thermometer within 15 minutes and charged with 1.00 g N 3600, 4.54 g of DMF, and 0.02 g of bismuth neodecanoate at 50 °C while stirring the mixture under a nitrogen atmosphere with an upper mechanical stirrer. After the feeding was completed, the mixture was further heated to 80 °C. Samples were taken regularly and the reaction progress was monitored using a Bruker Alpha FT-IR spectrometer until no change in the NCO-stretching was observed at 2200 - 2300 cm -1 Subsequently, 0.03 g of 1-butanol was added to the mixture, and then the reaction was further continued until the above NCO-stretching peak completely disappeared. The solution was concentrated to a 25 wt% solution under vacuum to produce a slightly viscous liquid.

[0212] The calculated molecular weights of the theoretical main components were 1023.69 Da (3 aziridines), 1322.84 Da (2 aziridines, 10 EG repeating units), and 1366.87 Da (2 aziridines, 11 EG repeating units), respectively.

[0213]

[0214] The molecular weight was confirmed by Maldi-TOF-MS: calculated value [M+Na+] = 1046.69 Da; measured value [M+Na+] = 1046.16 Da.

[0215]

[0216] The molecular weight was confirmed by Maldi-TOF-MS: calculated value [M+Na+] = 1345.84 Da; measured value [M+Na+] = 1345.31 Da.

[0217]

[0218] The molecular weight was confirmed by Maldi-TOF-MS: calculated value [M+Na+] = 1389.87 Da; measured value [M+Na+] = 1389.52 Da.

[0219] The following components with a mass below 820 Da were determined and quantified by LC-MS:

[0220] The amount present in the composition is less than 0.01% by weight, and

[0221] The amount of is less than 0.01% by weight.

[0222] According to the procedure of standard DIN 68861-1:2011-01, the performance of the synthetic compound as a crosslinking agent was evaluated using a spot test on a coated surface. For these tests, 2.4 parts of the crosslinking agent solution were added to 10 parts of P1 and with continuous stirring, and the resulting mixture was further stirred for 30 minutes. After that, 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 then dried at 25 °C for 24 hours. Subsequently, a piece of absorbent cotton was soaked in 1:1 EtOH:softened water and placed on the film for different times. After removing the EtOH and allowing it to recover for 60 minutes, the following results were obtained (1 point indicates complete degradation of the film, and 5 points indicates no visible damage):

[0223] Ethanol spot test samples 30 minutes 240 minutes Test 2-1 3 3

[0224] Test 2-2 1 1

[0225] Genotoxicity test

[0226]

[0227] The genotoxicity test results showed that the crosslinking agent composition of Example 2 is non-genotoxic.

[0228] Example 3

[0229] A round-bottom flask equipped with a condenser was placed under a nitrogen atmosphere and charged with ethylenimine (40.0 g), Cardura E10P (151.5 g), and K2CO3 (4.00 g) and heated to 40 °C. Thereafter, the mixture was stirred at T = 40 °C for 48 hours. After filtration Vacuum The excess EI was removed and then further purified by vacuum distillation to obtain a colorless, low-viscosity liquid.

[0230] 1.35 g of the obtained material (3-(aziridin-1-yl)-2-hydroxypropyl neodecanoate) was charged into a feed funnel together with 2.40 g of dimethylformamide. The mixture was added to a reaction flask equipped with a thermometer within 15 minutes and charged with 1.00 g N 3600, 4.80 g of DMF, and 0.02 g of bismuth neodecanoate while stirring the mixture with a mechanical top stirrer under a nitrogen atmosphere. After the feeding was completed, the mixture was further heated to 80 °C. Samples were taken regularly and the reaction progress was monitored using a Bruker Alpha FT-IR spectrometer until no change in the NCO-stretch was observed at 2200 - 2300 cm -1 Subsequently, 0.03 g of 1-butanol was added to the mixture and then further reacted until the above NCO-stretch peak completely disappeared. The solution was concentrated in vacuo to a 25 wt% solution, yielding a slightly viscous liquid.

[0231] The calculated molecular weight of the theoretical main component is 1317.91 Da, and the chemical structure is as follows:

[0232]

[0233] The molecular weight was confirmed by Maldi-TOF-MS: calculated value [M+Na+] = 1340.91 Da; measured value [M+Na+] = 1340.88 Da.

[0234] The following components with a mass below 820 Da were determined and quantified by LC-MS:

[0235] The amount present in the composition is below 0.01 wt%, and

[0236] the amount present is 0.07 wt%.

[0237] According to the procedure of standard DIN 68861-1:2011-01, the performance of the synthetic compound as a crosslinking agent was evaluated using a spot test on the coated surface. For these tests, 2.0 parts of the crosslinking agent solution was added to 10 parts of P1 and with continuous stirring, and the resulting mixture was further stirred for 30 minutes. After that, the coating composition was filtered and applied to a Leneta test card using a 100 μm wire bar coater (Test 3-1). As a reference, a film was also cast from the same composition lacking the crosslinking agent (Test 3-2). The film was dried at 25 °C for 16 hours, then annealed at 50 °C for 1 hour and dried at 25 °C for 24 hours. Subsequently, a piece of absorbent cotton was soaked in 1:1 EtOH:softened water and placed on the film for different times. After removing the EtOH and allowing to recover for 60 minutes, the following results were obtained (1 point indicates complete degradation of the film and 5 points indicates no visible damage):

[0238] Ethanol spot test

[0239]

[0240] Genotoxicity test

[0241]

[0242] The genotoxicity test results showed that the crosslinking agent composition of Example 3 was non-genotoxic.

[0243] Example 4

[0244] A round-bottomed flask equipped with a condenser was placed under a N2 atmosphere and charged with ethyleneimine (50.0 g), n-butyl glycidyl ether (108.0 g) and K2CO3 (5.00 g) and heated to 40 °C within 30 minutes. Then the mixture was stirred at T = 40 °C for 48 hours. After filtration, the excess EI was removed in vacuo and subsequently further purified by vacuum distillation to obtain a colorless low-viscosity liquid.

[0245] 3.37 g of the resulting material (1-(aziridin-1-yl)-3-butoxypropan-2-ol) was charged into a feed flask together with 5.4 g XTJ-436 (CAS No. 118270-87-4, purchased from Huntsman) and 30 g of dimethylformamide. The mixture was added to a reaction flask equipped with a thermometer within 15 minutes and charged with 5.00 g N 3600, 40 g of DMF and 0.12 g of bismuth neodecanoate at 50 °C while stirring the mixture under a nitrogen atmosphere with an overhead mechanical stirrer. After the feeding was completed, the mixture was further heated to 80 °C. Samples were taken regularly and the reaction progress was monitored using a Bruker Alpha FT-IR spectrometer until in the range of 2200 - 2300 cm-1 No change in NCO-stretching was observed. Subsequently, 0.16 g of 1-butanol was added to the mixture, and the reaction was further continued until the above NCO-stretching peak completely disappeared. The solution was concentrated in vacuo to a 25 wt% solution, yielding a slightly viscous liquid.

[0246] The calculated molecular weights of the theoretical main components were 1023.69 Da (3 aziridines), 1824.30 Da (2 aziridines, 13 PO repeat units), and 1882.34 Da (2 aziridines, 14 PO repeat units), respectively.

[0247]

[0248] The molecular weight was confirmed by Maldi-TOF-MS: calculated value [M+Na+] = 1046.69 Da; measured value [M+Na+] = 1046.71 Da.

[0249]

[0250] The molecular weight was confirmed by Maldi-TOF-MS: calculated value [M+Na+] = 1847.29 Da; measured value [M+Na+] = 1847.40 Da.

[0251]

[0252] The molecular weight was confirmed by Maldi-TOF-MS: calculated value [M+Na+] = 1905.33 Da; measured value [M+Na+] = 1905.44 Da.

[0253] The following components with a mass below 820 Da were determined and quantified by LC-MS:

[0254] present in the composition in an amount below 0.01 wt%, and

[0255] present in an amount below 0.01 wt%.

[0256] According to the procedure of standard DIN 68861-1:2011-01, the performance of synthetic compounds as crosslinking agents was evaluated using spot tests on coated surfaces. For these tests, 1.0 part of the crosslinking agent solution was added to 15 parts of P1 and with continuous stirring, and the resulting mixture was further stirred for 30 minutes. After that, the coating composition was filtered and applied to a Leneta test card (Test 4-1) using a 100 μm wire rod applicator. As a reference, a film was also cast from the same composition lacking the crosslinking agent (Test 4-2). The film was dried at 25 °C for 16 hours, then annealed at 50 °C for 1 hour, and then dried at 25 °C for 24 hours. Subsequently, a piece of absorbent cotton was soaked in 1:1 EtOH:softened water and placed on the film for different times. After removing the EtOH and allowing 60 minutes for recovery, the following results were obtained (1 point indicates complete degradation of the film, 5 points indicates no visible damage):

[0257] Ethanol spot test

[0258]

[0259] The following synthetic aqueous acrylic adhesive was prepared.

[0260] Sodium dodecyl sulfate (solid in 30% water, 18.6 g solution) and softened water (711 g) were charged into a 2 L four-necked flask equipped with a thermometer and an overhead stirrer. The reactor was placed under a N2 atmosphere and heated to 82 °C. A mixture of softened water (112 g), sodium dodecyl sulfate (solid in 30% water, 37.2 g solution), methyl methacrylate (174.41 g), n-butyl acrylate (488.44 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 softened water (89.61 g) and placed in a small feed funnel (initiator feed). Ammonium persulfate (1.75 g) was dissolved in softened water (10.5 g), and this solution was added to the reactor phase. Subsequently, 5 vol% of the monomer feed was immediately added to the reactor phase. Then the reaction mixture exothermed to 85 °C and was 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 complete, the monomer feed funnel was rinsed with softened water (18.9 g), and the reaction temperature was held at 85 °C for 45 minutes. Subsequently, the mixture was cooled to room temperature and adjusted to pH = 7.2 with ammonia solution (6.25 wt.% in softened water), and further adjusted to 40% solids with additional softened water.

[0261] For further spot testing, the performance of the synthetic compound as a crosslinking agent was evaluated using spot testing on the coating surface according to the procedure of standard DIN 68861-1:2011-01. In these tests, 1.1 parts of the crosslinking agent solution were added to 15 parts of the above acrylic binder while stirring continuously, and the resulting mixture was further stirred for 30 minutes. Thereafter, the coating composition was filtered and applied to a Leneta test card (Test 4-3) using a 100 μm wire rod applicator. As a reference, a film was also cast from the same composition without the crosslinking agent (Test 4-4). The film was dried at 25 °C for 16 hours, then annealed at 50 °C for 1 hour and dried again at 25 °C for 24 hours. Subsequently, a piece of absorbent cotton was soaked in 1:1 EtOH:softened water and placed on the film for different times. After removing the EtOH and allowing to recover for 60 minutes, the following results were obtained (1 point indicates complete degradation of the film and 5 points indicates no visible damage): Ethanol spot test

[0262]

[0263] Genotoxicity test

[0264]

[0265] The genotoxicity test results showed that the crosslinking agent composition of Example 4 was non-genotoxic.

[0266] Example 5

[0267] A round-bottomed flask equipped with a condenser was placed under a N2 atmosphere and charged with ethyleneimine (50.0 g), n-butyl glycidyl ether (108.0 g) and K2CO3 (5.00 g) and heated to 40 °C within 30 minutes. The mixture was then stirred at T = 40 °C for 48 hours. After filtration, the excess EI was removed in vacuo and then further purified by vacuum distillation to obtain a colorless low-viscosity liquid.

[0268] 1-(Aziridin-1-yl)-3-butoxypropan-2-ol) was charged into a reaction flask equipped with a thermometer together with 0.02 g of bismuth neodecanoate and 32 g of dimethylformamide. The mixture was stirred with an overhead mechanical stirrer under a nitrogen atmosphere and heated to 50 °C. Then 6.30 g of a solution of N 3900 in 34 g of dimethylformamide was added dropwise to the reaction flask within 15 minutes while maintaining the reaction temperature constant at 50 °C. Samples were taken periodically and the reaction progress was monitored using a Bruker Alpha FT-IR spectrometer until at 2200-2300 cm -1No change in the NCO-stretching was observed. Subsequently, 0.21 g of 1-butanol was added to the mixture and the reaction was further continued until the above NCO-stretching peak completely disappeared. The solution was concentrated in vacuo to a 25 wt% solution, yielding a slightly viscous liquid.

[0269] The calculated theoretical molecular weight of the main component is 1023.69 Da and the chemical structure is as follows:

[0270]

[0271] The molecular weight was confirmed by Maldi-TOF-MS: calculated value [M+Na+] = 1046.69 Da;; found value [M+Na+] = 1046.73 Da.

[0272] The following components with a mass below 820 Da were determined and quantified by LC-MS:

[0273] was present in the composition in an amount of 0.07 wt% and

[0274] was present in an amount below 0.01 wt% and

[0275] was present in an amount below 0.01 wt%.

[0276] According to the procedure of standard DIN 68861-1:2011-01, the performance of the synthetic compound as a crosslinker was evaluated using a dot test on a coated surface. For these tests, 1.4 parts of the crosslinker solution were added to 10 parts of P1 and stirred continuously, and the resulting mixture was further stirred for 30 minutes. After that, the coating composition was filtered and applied to a Leneta test card (Test 5-1) using a 100 μm wire-wound applicator. As a reference, a film was also cast from the same composition lacking the crosslinker (Test 5-2). The films were dried at 25 °C for 16 h, then annealed at 50 °C for 1 h and then dried at 25 °C for 24 h. Subsequently, a piece of absorbent cotton was soaked in 1:1 EtOH:softened water and placed on the film for different times. After removing the EtOH and allowing to recover for 60 minutes, the following results were obtained (1 point indicates complete degradation of the film and 5 points indicates no visible damage):

[0277] Ethanol dot test

[0278]

[0279] Genotoxicity test

[0280]

[0281]

[0282] The results of genotoxicity tests indicate that the crosslinking agent composition of Example 5 is non-genotoxic.

[0283] Comparative Example 5

[0284] Comparative Example 5 is pentaerythritol tris(3-(1-aziridinyl)propionate) obtained from ABCR, CAS No. 57116-45-7. The chemical structure is shown below:

[0285]

[0286] Genotoxicity test

[0287]

[0288] The results of genotoxicity tests indicate that the crosslinking agent of Comparative Example 5 is genotoxic.

Claims

1. A polyaziridine compound having: a) 2 to 6 of the following structural units (A): where m is an integer from 1 to 6; and R' and R'' are according to (1) or (2): (1) R' = H or an aliphatic hydrocarbon group having 1 to 14 carbon atoms, and R” = an alicyclic hydrocarbon group having 5 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 12 carbon atoms, CH2-O-(C=O)-R”’, CH2-O-R”” or CH2-(OCR””’HCR””’H) n -OR”””, where R”’ is an aliphatic hydrocarbon group having 1 to 14 carbon atoms, R”” is an aliphatic hydrocarbon group having 1 to 14 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, n is from 1 to 35, R””’ is independently H or an aliphatic hydrocarbon group having 1 to 14 carbon atoms, and R””” is an aliphatic hydrocarbon group having 1 to 4 carbon atoms; and (2) R' and R'' together form a saturated alicyclic hydrocarbon group having 5 to 8 carbon atoms; b) one or more linking chains, where each of these linking chains links two of the structural units A, the linking chain being defined as the shortest chain of contiguous atoms that links two structural units A, and where the linking chain is a set of covalently linked atoms, the set of atoms consisting of i) carbon atoms, ii) carbon and nitrogen atoms, or iii) carbon, oxygen and nitrogen atoms; c) a molecular weight in the range of 840 to 5000 daltons, where the molecular weight is determined using MALDI-TOF mass spectrometry; and d) one or more linking groups, where each of these linking groups links two of the structural units A, where the linking group includes at least one functional group selected from the following: aliphatic hydrocarbon functional group, alicyclic hydrocarbon functional group, isocyanurate functional group, iminodioxadione functional group, and any combination thereof.

2. The polyaziridine compound according to claim 1, wherein m is 1; R' and R'' are according to (1) or (2): (1) R' = H or an alkyl group having 1 to 2 carbon atoms, and R'' = CH2-O-(C=O)-R''', CH2-O-R'', or CH2- (OCR””’HCR””’H) n -OR””” wherein R”’ is an alkyl group having 1 to 14 carbon atoms, R”” is an alkyl group having 1 - 14 carbon atoms, n is from 1 to 35, R””’ is independently H or methyl and R””” is an alkyl group having 1 - 4 carbon atoms; and (2) R' and R'' form part of a saturated alicyclic hydrocarbon group having 5 to 8 carbon atoms.

3. The polyaziridine compound according to any one of claims 1 to 2, wherein R' = H, and R” = an alicyclic hydrocarbon group having 5 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 12 carbon atoms, CH2-O-(C=O)-R”’, CH2-O-R”” or CH2-(OCR””’HCR””’H) n -OR”””, where R”’ is an aliphatic hydrocarbon group having 1 to 14 carbon atoms, and R”” is an aliphatic hydrocarbon group having 1 to 14 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, and n is from 1 to 35 R''' is independently H or an aliphatic hydrocarbon group having 1 to 14 carbon atoms and R''' is an aliphatic hydrocarbon group having 1 to 4 carbon atoms.

4. The polyaziridine compound according to any one of claims 1 to 2, wherein R’ is H and R” = CH2-O-(C=O)-R”’, CH2-O-R”” or CH2-(OCH2CH2) n -OCH3, where R”’ is an alkyl group having 3 to 12 carbon atoms and R”” is an alkyl group having 1 to 14 carbon atoms.

5. The polyaziridine compound according to any one of claims 1 to 2, wherein the polyaziridine compound contains 2 or 3 structural units (A).

6. The polyaziridine compound according to any one of claims 1 to 2, wherein the linking chain consists of 4 to 300 atoms.

7. The polyaziridine compound according to any one of claims 1 to 2, wherein the polyaziridine compound has a molecular weight of 840 to 3800 daltons, where the molecular weight is determined using MALDI-TOF mass spectrometry.

8. The polyaziridine compound according to any one of claims 1 to 2, characterized in that, The linking group of the polyaziridine compound consists of at least one functional group selected from the following: aliphatic hydrocarbon functional group, isocyanurate functional group, iminodioxadione functional group, and any combination thereof.

9. The polyaziridine compound according to any one of claims 1 to 2, wherein the polyaziridine compound comprises one or more linking groups, each of these linking groups linking 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 cycloaliphatic 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 the side groups have the following structural formula: n' is the number of repeating units and is an integer from 1 to 50, X is O or NH, R7 and R8 are independently H or CH3 in each repeating unit, R9 is an aliphatic hydrocarbon group, or a cycloaliphatic hydrocarbon group, and R 10 contains at most 20 carbon atoms and is an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, or a combination thereof.

10. The polyaziridine compound according to claim 9, wherein X is O and R7 and R8 are H.

11. The polyaziridine compound according to claim 9, wherein the polyaziridine compound contains 2 structural units (A).

12. The polyaziridine compound according to claim 11, wherein 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 R9 is an aliphatic hydrocarbon group, wherein the first aliphatic hydrocarbon functional group, the second aliphatic hydrocarbon functional group and R9 are the same.

13. A crosslinking agent composition comprising at least one polyaziridine compound according to any one of claims 1 to 12 and further comprising at least one additional component.

14. The crosslinking agent composition according to claim 13, wherein An aziridine-functional molecule having a molecular weight of less than 820 daltons, in an amount less than 1.5% by weight relative to the total weight of the crosslinking agent composition, wherein the molecular weight is determined using LC-MS.

15. The crosslinking agent composition according to claim 13 or 14, wherein the crosslinking agent composition comprises less than 5% by weight of water.

16. Use of the polyaziridine compound according to any one of claims 1 to 12 or the crosslinking agent composition according to any one of claims 13 to 15 for crosslinking a carboxylic acid-functional polymer dissolved and / or dispersed in an aqueous medium, wherein the carboxylic acid-functional polymer contains carboxylic acid groups and / or carboxylic acid ester groups.

17. A two-component coating system comprising a first component and a second component, the first component and the second component being separate and different from each other, and wherein the first component comprises a dissolved and / or dispersed carboxylic acid-functional polymer, wherein the carboxylic acid-functional polymer contains carboxylic acid groups and / or carboxylic acid ester groups, and the second component comprises a polyaziridine compound according to any one of claims 1 to 12 or the second component is a crosslinking agent composition according to any one of claims 13 to 15.

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