TWO-COMPONENT COATING SYSTEM

Abstract

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

##STR00001##

Claims

1. A two-component coating system comprising a first component and a second component each of which is separate and distinct from each other, wherein the first component comprises a carboxylic acid functional polymer dissolved and/or dispersed in an aqueous medium, whereby the carboxylic acid functional polymer contains carboxylic acid groups and/or carboxylate groups, and the second component comprises a multi-aziridine compound having: a) from 2 to 6 of the following structural units (A): ##STR00037## whereby m is an integer from 1 to 6, and R′ and R″ are both H; b) one or more linking chains wherein each one of these linking chains links two of the structural units A, whereby a linking chain is the shortest chain of consecutive atoms that links two structural units A; c) one or more connecting groups whereby each one of the connecting groups connects two of the structural units A and whereby the connecting groups consist of at least one functionality selected from aliphatic hydrocarbon functionality, cycloaliphatic hydrocarbon functionality, aromatic hydrocarbon functionality, isocyanurate functionality, iminooxadiazindione functionality, ether functionality, ester functionality, amide functionality, carbonate functionality, urethane functionality, urea functionality, biuret functionality, allophanate functionality, uretdione functionality and any combination thereof; and d) a molecular weight in the range from 840 Daltons to 5000 Daltons, wherein the molecular weight is determined using MALDI-TOF mass spectrometry as described in the description.

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

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

4. The two-component coating system according to claim 1, wherein the linking chains consist of from 4 to 300 atoms, more preferably from 5 to 250 and most preferably from 6 to 100 atoms and the linking chains are a collection of atoms covalently connected which collection of atoms consists of i) carbon atoms, ii) carbon and nitrogen atoms, or iii) carbon, oxygen and nitrogen atoms.

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

6. The two-component coating system according to claim 1, wherein the multi-aziridine compound has a molecular weight of from 840 to 3800 Daltons.

7. The two-component coating system according to claim 1, wherein the connecting groups of the multi-aziridine compound consist of at least one functionality selected from: aliphatic hydrocarbon functionality, cycloaliphatic hydrocarbon functionality, aromatic hydrocarbon functionality, isocyanurate functionality, iminooxadiazindione functionality, urethane functionality, urea functionality, biuret functionality and any combination thereof.

8. The two-component coating system according to claim 1, wherein the multi-aziridine compound comprises one or more connecting groups wherein each one of these connecting groups connects two of the structural units A, wherein the connecting groups consist of (i) at least two aliphatic hydrocarbon functionality or at least two cycloaliphatic hydrocarbon functionality and (ii) an isocyanurate functionality or an iminooxadiazindione functionality, and wherein a pendant group is present on a connecting group, whereby the pendant group has the following structural formula: ##STR00038## 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. X is O or NH, R.sub.7 and R.sub.8 are independently H or CH.sub.3 in each repeating unit, R.sub.9 is an aliphatic hydrocarbon group, preferably containing from 1 to 8 carbon atoms, or a cycloaliphatic hydrocarbon group, preferably containing from 4 to 10 carbon atoms, and R.sub.10 contains at most 20 carbon atoms and is an aliphatic, cycloaliphatic or aromatic hydrocarbon group or a combination thereof.

9. The two-component coating system according to claim 8, wherein X is O and R.sub.7 and R.sub.8 are H.

10. The two-component coating system according to claim 8, wherein the multi-aziridine compound contains 2 structural units (A).

11. The two-component coating system according to claim 10, wherein the connecting group consists of the array of the following consecutive functionalities: a first aliphatic hydrocarbon functionality, an isocyanurate functionality or an iminooxadiazindione functionality, and a second aliphatic hydrocarbon functionality, and R.sub.9 is an aliphatic hydrocarbon group, whereby the first and second aliphatic hydrocarbon functionality and R.sub.9 are identical.

12. The two-component coating system according to claim 1, wherein the multi-aziridine compound contains polyoxyethylene (—O—CH2-CH2-).sub.x group(s) in an amount of at least 0.1 wt. %, preferably at least 6 wt. %, more preferably at least 10 wt. % and in an amount of less than 45 wt. %, more preferably less than 25 wt. % and most preferably less than 16 wt. %, relative to the multi-aziridine compound.

13. The two-component coating system according to claim 1, wherein the multi-aziridine compound is obtained by reacting at least a polyisocyanate and a compound B with the following structural formula: ##STR00039## whereby the molar ratio of compound B to polyisocyanate is from 2 to 6, more preferably from 2 to 4 and most preferably from 2 to 3, and whereby m, R′, and R″, are defined in previous claims.

14. The two-component coating system according to claim 13, wherein the polyisocyanate is a polyisocyanate with aliphatic reactivity in which all of the isocyanate groups are directly bonded to aliphatic or cycloaliphatic hydrocarbon groups, irrespective of whether aromatic hydrocarbon groups are also present.

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

16. The two-component coating system according to claim 15, wherein the amount of aziridine functional molecules having a molecular weight lower than 820 Daltons is lower than 1.5 wt. %, preferably lower than 1 wt. %, relative to the total weight of the crosslinker composition, whereby the molecular weight is determined using LC-MS as described in the description, and wherein the crosslinker composition contains less than 5 wt. % of water.

17. A substrate having a coating obtained by (i) applying a coating composition obtained by mixing the first and second component of the two-component system according to claim 1 to a substrate and (ii) drying the coating composition by evaporation of volatiles.

18. A multi-aziridine compound having: a) from 2 to 6 of the following structural units (A): ##STR00040## whereby m is an integer from 1 to 6; and R′ and R″ are both H, b) one or more connecting groups wherein each one of these connecting groups connects two of the structural units A and wherein the connecting groups consist of (i) at least two aliphatic hydrocarbon functionality or at least two cycloaliphatic hydrocarbon functionality and (ii) an isocyanurate functionality or an iminooxadiazindione functionality, and wherein a pendant group is present on a connecting group, whereby the pendant group has the following structural formula: ##STR00041## 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, X is O or NH, R.sub.7 and R.sub.8 are independently H or CH.sub.3 in each repeating unit, R.sub.9 is an aliphatic hydrocarbon group, preferably containing from 1 to 8 carbon atoms, or a cycloaliphatic hydrocarbon group, preferably containing from 4 to 10 carbon atoms, and R.sub.10 contains at most 20 carbon atoms and is an aliphatic, cycloaliphatic or aromatic hydrocarbon group or a combination thereof, and c) a molecular weight in the range from 840 Daltons to 5000 Daltons, wherein the molecular weight is measured using MALDI-TOF mass spectrometry.

19. The multi-aziridine compound according to claim 18, wherein X is O and R.sub.7 and R.sub.8 are independently H.

20. The multi-aziridine compound according to claim 18, wherein the multi-aziridine compound contains 2 structural units (A).

21. The multi-aziridine compound according to claim 18, wherein the connecting group consists of the array of the following consecutive functionalities: a first aliphatic hydrocarbon functionality, an isocyanurate functionality or an iminooxadiazindione functionality, and a second aliphatic hydrocarbon functionality, and R.sub.9 is an aliphatic hydrocarbon group, whereby the first and second aliphatic hydrocarbon functionality and R.sub.9 are identical.

Description

PREPARATIVE EXAMPLE 2: SYNTHESIS OF WATERBORNE ACRYLIC POLYMER A1

[0088] A 2 L four-necked flask equipped with a thermometer and overhead stirrer was charged with sodium lauryl sulphate (30% solids in water, 18.6 grams of solution) and demineralized water (711 grams). The reactor phase was placed under N.sub.2 atmosphere and heated to 82° C. A mixture of demineralized water (112 grams), sodium lauryl sulphate (30% solids in water, 37.2 grams of solution), methyl methacrylate (209.3 grams), n-butyl acrylate (453.56 grams) and methacrylic acid (34.88 grams) was placed in a large feeding funnel and emulsified with an overhead stirrer (monomer feed). Ammonium persulphate (1.75 grams) was dissolved in demineralized water (89.61 grams) and placed in a small feeding funnel (initiator feed). Ammonium persulphate (1.75 grams) was dissolved in demineralized water (10.5 grams), and this solution was added to the reactor phase. Immediately afterwards, 5% by volume of the monomer feed was added to the reactor phase. The reaction mixture then exothermed to 85° C. and was kept at 85° C. for 5 minutes. Then, the residual monomer feed and the initiator feed were fed to the reaction mixture over 90 minutes, maintaining a temperature of 85° C. After completion of the feeds, the monomer feed funnel was rinsed with demineralized water (18.9 grams) and reaction temperature maintained at 85° C. for 45 minutes. Subsequently, the mixture was cooled to room temperature and brought to pH=7.2 with ammonia solution (6.25 wt. % in demineralized water), and brought to 40% solids with further demineralized water.

Genotoxicity Testing

[0089] Genotoxicity of examples and comparatives was evaluated by the ToxTracker® assay (Toxys, Leiden, the Netherlands). The ToxTracker assay is a panel of several 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 methodology uses a two step-approach.

[0090] In the first step a dose range finding was performed using wild-type mES cells (strain B4418). 20 different concentrations for each compound was tested, starting at 10 mM in DMSO as highest concentration and nineteen consecutive 2-fold dilutions.

[0091] Next, genotoxicity of examples and comparatives was evaluated using specific genes linked to reporter genes for the detection of DNA damage; i.e. Bscl2 (as elucidated by U.S. Pat. No. 9,695,481B2 and EP2616484B1) and Rtkn (Hendriks et. al. Toxicol. Sci. 2015, 150, 190-203) biomarkers.

[0092] Genotoxicity was evaluated at 10, 25 and 50% cytotoxicity in absence and presence of rat S9 liver extract-based metabolizing systems (aroclor1254-induced rats, Moltox, Boone, N.C., USA). The independent cell lines were seeded in 96-well cell culture plates, 24 h after seeding the cells in the 96-well plates, fresh ES cell medium containing the diluted test substance was added to the cells. For each tested compound, five concentrations are tested in 2-fold dilutions. The highest sample concentration will induce significant cytotoxicity (50-70%). In case of no or low cytotoxicity, 10 mM or the maximum soluble mixture concentration is used as maximum test concentration. Cytotoxicity is determined by cell count after 24 h exposure using a Guava easyCyte 10HT flow cytometer (Millipore).

[0093] GFP reporter induction is always compared to a vehicle control treatment. DMSO concentration is similar in all wells for a particular compound and never exceeds 1%. All compounds were tested in at least three completely independent repeat experiments. Positive reference treatment with cisplatin (DNA damage) were included in all experiments. Metabolic was evaluated by addition of S9 liver extract. Cells are exposed to five concentrations of the test compound in the presence of S9 and required co-factors (RegenSysA+B, Moltox, Boone, N.C., USA) for 3 h. After washing, cells are incubated for 24 h in fresh ES cell medium. Induction of the GFP reporters is determined after 24 h exposure using a Guava easyCyte 10HT flow cytometer (Millipore). Only GFP expression in intact single cells is determined. Mean GFP fluorescence and cell concentrations in each well is measured, which is used for cytotoxicity assessment. Data was analyzed using ToxPlot software (Toxys, Leiden, the Netherlands). The induction levels reported are at compound concentrations that induce 10%, 25% and 50% cytotoxicity after 3 h exposure in the presence of S9 rat liver extract and 24 h recovery or alternatively after 24 h exposure when not in the presence of S9 rat liver extract.

[0094] A positive induction level of the biomarkers is defined as equal to or higher than a 2-fold induction at at least one of 10, 25 and 50% cytotoxicity in the absence or presence of the metabolizing system rat S9 liver extract; a weakly positive induction as higher than 1.5-fold and lower than 2-fold induction at at least one of 10, 25 and 50% cytotoxicity (but lower than 2-fold at 10, 25 and 50% cytotoxicity) in the absence or presence of the metabolizing system rat S9 liver extract and a negative as lower than or equal to a 1.5-fold induction at 10, 25 and 50% cytotoxicity in the absence and presence of rat S9 liver extract-based metabolizing systems.

Components and Abbreviations Used:

[0095] Dimethylformamide (CAS No. 68-12-2) was obtained from Acros Organics (a division of Thermo Fisher Scientific).

[0096] Di(propylene glycol) dimethyl ether (Proglyde DMM, CAS No. 111109-77-4) was obtained from Dow Inc

[0097] Trimethylolpropane tris(2-methyl-1-aziridinepropionate), CAS No. 64265-57-2, CX-100 was obtained from DSM.

[0098] Pentaerythritol tris(3-(1-aziridinyl)propionate), CAS number 57116-45-7 was obtained from ABCR.

[0099] IPDI (5-isocyanato-1-(isocyanatomethyl)-1,3,3-trimethylcyclohexane, Desmodur® I, isophorone diisocyanate, CAS No. 4098-71-9) was obtained from Covestro.

[0100] Polyethylene Glycol Monomethyl Ether (CAS No. 9004-74-4) with a number average molecular weight of 1000 Da was obtained from Tokyo Chemical Industry Co., Ltd.

[0101] Vestanat® T 1890/100, an isophorone diisocyanate based isocyanurate (CAS No. 67873-91-0) was obtained from Evonik.

[0102] Desmodur® N3600 was obtained from Covestro.

[0103] 1-methoxy-2-propanol acetate (propylene glycol methyl ether acetate, CAS No. 108-65-6) was obtained from Shell Chemicals.

[0104] 1-(2-hydroxyethyl)ethyleneimine) (CAS No. 1072-52-2) was obtained from Tokyo Chemical Industry Co., Ltd.

[0105] Jeffamine® XTJ-436 (CAS No. 118270-87-4) was obtained from Huntsman

[0106] Bismuth neodecanoate (CAS No. 34364-26-6) obtained from TIB chemicals AG (Mannheim, Germany).

[0107] Hydrazine (16% solution in water, CAS No. 302-01-2) was obtained from Honeywell.

[0108] Dimethylol propionic acid (DMPA, CAS No. 4767-03-7) was obtained from Perstop Polyols.

[0109] Triethylamine (TEA, CAS No. 121-44-8) was obtained from Arkema

[0110] 1-propanol (CAS No. 71-23-8) was obtained from Sigma-Aldrich.

[0111] Tin 2-ethylhexanoate (CAS No. 301-10-0) was obtained from Sigma-Aldrich.

[0112] Dibutyltindilaurate (CAS No. 77-58-7) was obtained from Sigma-Aldrich.

[0113] Tegomer® D3403 was obtained from Evonik.

[0114] Polypropyleneglycol with a number average molecular weight of 1000 Da and with a number average molecular weight of 2000 Da was obtained from BASF.

[0115] 3-Methyl-1-phenyl-2-phospholene-1-oxide (CAS No. 707-61-9) was obtained from Sigma-Aldrich.

[0116] 1-Butanol (CAS No. 71-36-3) was obtained from Sigma-Aldrich.

[0117] Sodium lauryl sulphate (30% solution in water, CAS No. 73296-89-6) was obtained from BASF.

[0118] Methyl methacrylate (CAS No. 80-62-6) was obtained from Lucite Int.

[0119] n-Butyl acrylate (CAS No. 141-32-2) was obtained from Dow Chemical.

[0120] Methacrylic acid (CAS No. 79-41-4) was obtained from Lucite Int.

[0121] Ammonium persulphate (CAS No. 7727-54-0) was obtained from United Initiators.

[0122] Ammonia (25% solution in water, CAS No. 1336-21-6) was obtained from Merck

COMPARATIVE EXAMPLE 1

[0123] Comparative Example 1 is trimethylolpropane tris(2-methyl-1-aziridinepropionate), CAS number 64265-57-2 obtained from DSM. Chemical structure is shown below.

##STR00024##

[0124] For reference, the performance of trimethylolpropane tris(2-methyl-1-aziridinepropionate) as a crosslinker was assessed using spot tests on coating surfaces, based on procedures from the DIN 68861-1:2011-01 standard. For these tests, 0.23 parts of the compound were mixed with 0.60 parts of Proglyde™ DMM (dipropylene glycol dimethyl ether, mixture of isomers) and incubated at 80° C. for 10 minutes under regular agitation. Subsequently, 0.56 parts of the resulting solution were added to 20 parts of P1 under continuous stirring, and the resulting mixture was further stirred for 30 minutes. Afterwards, this coating composition was filtered and applied to Leneta test cards using 100 μm wire rod applicators (Test C1-1). The films were dried for 16 hours at 25° C., then annealed at 50° C. for 1 hour and further dried for 24 hours at 25° C. Subsequently, a piece of cotton wool was soaked in 1:1 EtOH:demineralized water and placed on the film for various timespans. After removal of the EtOH and 60 minutes recovery, the following results were obtained (a score of 1 indicates complete degradation of the film, 5 indicates no damage visible):

[0125] Ethanol Spot Test

TABLE-US-00001 Sample 30 min 60 min 120 min 300 min Test C1-1 4 4 3 3

[0126] Genotoxicity Test

TABLE-US-00002 Without S9 rat liver extract With S9 rat liver extract concentration Bscl 2 Rtkn Bscl 2 Rtkn .fwdarw. 10 25 50 10 25 50 10 25 50 10 25 50 Comp. Ex. 1 1.2 1.5 2.0 1.4 2.0 3.2 1.7 2.3 2.1 3.0 4.3 3.4

[0127] The genotoxicity test results shows that the crosslinker of Comparative Example 1 is genotoxic.

EXAMPLE 1

[0128] 3.83 grams of 1-(2-hydroxyethyl)ethyleneimine) (Cas No. 1072-52-2, obtained from Tokyo Chemical Industry), 12.21 grams of a poly(ethylene glycol) monomethyl ether with an average Mn of 1000 Da and 126 grams of dimethylformamide were charged to a reaction flask equipped with a thermometer. The mixture was stirred with a mechanical upper stirrer under a nitrogen atmosphere and heated to 50° C., after which 0.12 grams of bismuth neodecanoate was added to the flask and a mixture of 15.00 grams of Vestanat® T 1890/100 in 63 grams of dimethylformamide was fed in 30 minutes to a reaction flask. After this, the mixture was heated further to 80° C. Samples were taken at regular intervals and the reaction progress was monitored using a Bruker Alpha FT-IR spectrometer until no change in NCO-stretch at 2200-2300 cm.sup.−1 was observed. Subsequently, 0.36 grams of 1-butanol were added to the mixture, followed by further reaction to complete disappearance the aforementioned NCO-stretch peak. The solvent was removed in vacuo to obtain an opaque waxy solid. The calculated molecular weights of the theoretical main components were 927.62 Da (three aziridines), 1797.12 (two aziridines, 21 EG repeating units) and 1841.15 Da (two aziridines, 22 EG repeating units) chemical structures are shown below.

##STR00025##

[0129] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+Na+]=950.62 Da; Obs. [M+Na+]=950.52 Da.

##STR00026##

[0130] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+Na+]=1820.12 Da; Obs. [M+Na+]=1820.15 Da.

##STR00027##

[0131] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+Na+]=1864.15 Da; Obs. [M+Na+]=1864.20 Da.

[0132] The following components with a mass below 820 Da were detected by LC-MS and quantified:

##STR00028##

was present in the composition at 0.04 wt %

[0133] Performance of the synthesized compound as a crosslinker was assessed using spot tests on coating surfaces, based on procedures from the DIN 68861-1:2011-01 standard. For these tests, 0.75 parts of the composition were mixed with 0.75 parts of 1-methoxy-2-propyl acetate and incubated at 80° C. for 10 minutes under regular agitation. Subsequently, 1.5 parts of the resulting solution were added to 10 parts of P1 under continuous stirring, and the resulting mixture was further stirred for 30 minutes. Afterwards, this coating composition was filtered and applied to Leneta test cards using 100 μm wire rod applicators (Test 1-1). For reference, films were also cast from the same composition lacking a crosslinker (Test 1-2). The films were dried for 16 hours at 25° C., then annealed at 50° C. for 1 hour and further dried fo 24 hours at 25° C. Subsequently, a piece of cotton wool was soaked in 1:1 EtOH:demineralized water and placed on the film for various timespans. After removal of the EtOH and 60 minutes recovery, the following results were obtained (a score of 1 indicates complete degradation of the film, 5 indicates no damage visible):

[0134] Ethanol Spot Test

TABLE-US-00003 Sample 30 min 240 min Test 1-1 4 4 Test 1-2 1 1

[0135] For further performance tests, 1.0 parts of the composition were mixed with 1.0 parts of 1-methoxy-2-propyl acetate and incubated at 80° C. for 10 minutes under regular agitation. Subsequently, 1.5 parts of the resulting solution were added to 10.5 parts of A1 under continuous stirring, and the resulting mixture was further stirred for 30 minutes. Afterwards, this coating composition was filtered and applied to Leneta test cards using 100 μm wire rod applicators (Test 1-3). For reference, films were also cast from the same composition lacking a crosslinker (Blank 1-4). The films were dried for 16 hours at 25° C., then annealed at 50° C. for 1 hour and further dried fo 24 hours at 25° C. Subsequently, a piece of cotton wool was soaked in 1:1 EtOH:demineralized water and placed on the film for various timespans. After removal of the EtOH and 60 minutes recovery, the following results were obtained (a score of 1 indicates complete degradation of the film, 5 indicates no damage visible):

TABLE-US-00004 Sample 60 min 240 min Test 1-3 3 3 Blank 1-4 1 1

Genotoxicity Test

[0136]

TABLE-US-00005 Without S9 rat liver extract With S9 rat liver extract concentration Bscl 2 Rtkn Bscl 2 Rtkn .fwdarw. 10 25 50 10 25 50 10 25 50 10 25 50 Ex. 1 1.2 1.3 1.3 1.2 1.1 1.0 1.2 1.3 1.3 1.3 1.1 1.3

[0137] The genotoxicity test results show that the crosslinker composition of Example 1 is non-genotoxic.

COMPARATIVE EXAMPLE 2

[0138] 15.0 grams of Desmodur N 3600 and 75 grams of dimethylformamide were charged to a reaction flask equipped with a thermometer. The mixture was stirred with a mechanical upper stirrer under a nitrogen atmosphere. The mixture was than heated to 50° C., whereafter 6.80 grams of 1-(2-hydroxyethyl)ethyleneimine was added. 15 minutes later 0.03 grams of bismuth neodecanoate was charged to the reaction flask, which was then heated further to 60° C. Samples were taken at regular intervals and the reaction progress was monitored using a Bruker Alpha FT-IR spectrometer until no NCO-stretch at 2200-2300 cm.sup.−1 was observed. The solvent was removed in vacuo to obtain a clear, slightly yellowish highly viscous liquid. The calculated molecular weight of the theoretical main component was 765.47 Da, chemical structure is shown below.

##STR00029##

[0139] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+K+]=804.43 Da; Obs. [M+K+]=804.27 Da.

Genotoxicity Test

[0140]

TABLE-US-00006 Without S9 rat liver extract With S9 rat liver extract concentration Bscl 2 Rtkn Bscl 2 Rtkn .fwdarw. 10 25 50 10 25 50 10 25 50 10 25 50 Comp. Ex. 2 1.1 1.3 1.4 1.7 2.4 2.8 1.4 1.9 1.9 2.0 3.4 3.0

[0141] The genotoxicity test results show that the reaction product of Comp Ex 2 is genotoxic.

EXAMPLE 2

[0142] 3.83 grams of 1-(2-hydroxyethyl)ethyleneimine) (Cas No. 1072-52-2, obtained from Tokyo Chemical Industry), 12.27 grams of Jeffamine® XTJ-436 (CAS number 118270-87-4, obtained from Huntsman) and 126 grams of dimethylformamide were charged to a reaction flask equipped with a thermometer. The mixture was stirred with a mechanical upper stirrer under a nitrogen atmosphere and heated to 50° C., after which 0.10 grams of bismuth neodecanoate was added to the flask and a mixture of 15.00 grams of Vestanat® T 1890/100 in 95 grams of dimethylformamide was fed in 30 minutes to a reaction flask. After this, the mixture was heated further to 80° C. Samples were taken at regular intervals and the reaction progress was monitored using a Bruker Alpha FT-IR spectrometer until no change in NCO-stretch at 2200-2300 cm.sup.−1 was observed. Subsequently, 0.36 grams of 1-butanol were added to the mixture, followed by further reaction to complete disappearance the aforementioned NCO-stretch peak. The solvent was removed in vacuo to obtain an opaque waxy solid. The calculated molecular weights of the theoretical main components were 927.62 Da (three aziridines), 1814.29 Da (two aziridines, 13 PO repeating units) and 1827.33 Da (two aziridines, 14P0 repeating units) chemical structures are shown below.

##STR00030##

[0143] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+Na+]=950.62 Da; Obs. [M+Na+]=950.52 Da.

##STR00031##

[0144] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+Na+]=1837.28 Da; Obs. [M+Na+]=1837.15 Da.

##STR00032##

[0145] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+Na+]=1895.32 Da; Obs. [M+Na+]=1895.15 Da.

[0146] The following components with a mass below 820 Da were detected by LC-MS and quantified:

##STR00033##

was present in the composition at 0.10 wt %.

[0147] Performance of the synthesized compound as a crosslinker was assessed using spot tests on coating surfaces, based on procedures from the DIN 68861-1:2011-01 standard. For these tests, 1.03 parts of the composition were mixed with 0.26 parts of dimethylformamide and incubated at 80° C. for 10 minutes under regular agitation. Subsequently, 1.29 parts of the resulting solution were added to 15 parts of P1 under continuous stirring, and the resulting mixture was further stirred for 30 minutes. Afterwards, this coating composition was filtered and applied to Leneta test cards using 100 μm wire rod applicators (Test 2-1). For reference, films were also cast from the same composition lacking a crosslinker (Test 2-2). The films were dried for 16 hours at 25° C., then annealed at 50° C. for 1 hour and further dried fo 24 hours at 25° C. Subsequently, a piece of cotton wool was soaked in 1:1 EtOH:demineralized water and placed on the film for various timespans. After removal of the EtOH and 60 minutes recovery, the following results were obtained (a score of 1 indicates complete degradation of the film, 5 indicates no damage visible):

[0148] Ethanol Spot Test

TABLE-US-00007 Sample 30 min 240 min Test 2-1 4 3 Test 2-2 1 1

[0149] For further performance tests, 1.45 parts of the composition were mixed with 0.39 parts of dimethylformamide and incubated at 80° C. for 10 minutes under regular agitation. Subsequently, 1.84 parts of the resulting solution were added to 10.5 parts of A1 under continuous stirring, and the resulting mixture was further stirred for 30 minutes. Afterwards, this coating composition was filtered and applied to Leneta test cards using 100 μm wire rod applicators (Test 2-3). For reference, films were also cast from the same composition lacking a crosslinker (Blank 2-4). The films were dried for 16 hours at 25° C., then annealed at 50° C. for 1 hour and further dried fo 24 hours at 25° C. Subsequently, a piece of cotton wool was soaked in 1:1 EtOH:demineralized water and placed on the film for various timespans. After removal of the EtOH and 60 minutes recovery, the following results were obtained (a score of 1 indicates complete degradation of the film, 5 indicates no damage visible):

TABLE-US-00008 Sample 60 min 240 min Test 2-3 3 3 Blank 2-4 1 1

Genotoxicity Test

[0150]

TABLE-US-00009 Without S9 rat liver extract With S9 rat liver extract concentration Bscl 2 Rtkn Bscl 2 Rtkn .fwdarw. 10 25 50 10 25 50 10 25 50 10 25 50 Ex. 2 1.2 1.5 1.6 1.4 1.3 1.2 1.1 1.6 1.7 1.4 1.3 1.2

[0151] The genotoxicity test results show that the crosslinker composition of Example 2 only has weakly positive induced genotoxicity.

COMPARATIVE EXAMPLE 3

[0152] Comparative Example 3 is pentaerythritol tris(3-(1-aziridinyl)propionate), CAS number 57116-45-7, obtained from ABCR. Chemical structure is shown below.

##STR00034##

Genotoxicity Test

[0153]

TABLE-US-00010 Without S9 rat liver extract With S9 rat liver extract concentration Bscl 2 Rtkn Bscl 2 Rtkn .fwdarw. 10 25 50 10 25 50 10 25 50 10 25 50 Comp. Ex. 3 1.2 1.4 2.1 1.2 1.7 3.5 1.1 1.5 2.3 1.3 2.1 4.3

[0154] The genotoxicity test results show that the crosslinker of Comparative Example 3 is genotoxic.

COMPARATIVE EXAMPLE 4 (EXAMPLE 5 U.S. Pat. No. 5,258,481)

[0155] Under a nitrogen atmosphere, 21.3 g (0.354 mole) of 1-propanol was added over a period of 6 hours to 78.7 g Isophorone diisocyanate (IPDI) and 0.01 g tin 2-ethyl hexanoate at 20-25° C., while stirring. After standing overnight, 196.3 g (0.883 mole) IPDI, 74.1 g (0.0628 mole) Tegomer D3403 and 2.4 g 3-Methyl-1-phenyl-2-phospholene-1-oxide were added. The mixture was heated while stirring to 150° C. The mixture was kept at 150° C. until NCO content was 7.0 wt %. Mixture was cooled to 80° C. and 333 g methoxypropyl acetate was added. A solution of isocyanate functional polycarbodiimide was obtained with a solid content of 50.6 wt % and an NCO content of 7.0 wt % on solids.

[0156] To 100 g of this isocyanate functional polycarbodiimide was added 7.0 g 1-(2-hydroxyethyl)ethyleneimine (0.08 mole). One drop of dibutyltin dilaurate was added. The mixture was heated to 80° C. while stirring. The mixture was kept at 80° C. for 1 hour. FTIR showed a small remaining isocyanate signal, which disappeared after a few days. The solution was further diluted with 8.0 g methoxypropyl acetate, resulting in a yellow solution with a solid content of 50.4 wt %. This aziridine functional carbodiimide contains 3.2 meq acid reactive groups (i.e aziridine and carbodiimide functionality) per gram solids. The generalized structure of this carbodiimide is depicted below.

##STR00035##

in which a, b and c indicates repeating units.

[0157] This generalized structure was confirmed by MALDI-TOF-MS, an example is shown below:

##STR00036##

[0158] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+Na+]=2043.34 Da; Obs. [M+Na+]=2043.32 Da.

Genotoxicity Test Results:

[0159]

TABLE-US-00011 Without S9 rat liver extract With S9 rat liver extract concentration Bscl 2 Rtkn Bscl 2 Rtkn .fwdarw. 10 25 50 10 25 50 10 25 50 10 25 50 Comp. Ex. 4 1.3 1.5 1.6 1.2 1.9 1.9 1.2 1.4 1.5 2.0 2.0 1.8

[0160] The genotoxicity test results demonstrate that the crosslinker of comparative example 4 is genotoxic.