MULTI-AZIRIDINE COMPOUND

Abstract

The present invention relates to a multi-aziridine compound having: ⋅a) from 2 to 6 of the following structural units (A): whereby R.sub.1 is H, R.sub.2 and R.sub.4 are independently chosen from H or an aliphatic hydrocarbon group containing from 1-4 carbon atoms, R.sub.3 is an aliphatic hydrocarbon group containing from 1-4 carbon atoms, R′═H or an aliphatic hydrocarbon group containing from 1 to 4 carbon atoms; R″ and R′″ are independently chosen from an aliphatic hydrocarbon group containing from 1 to 4 carbon atoms, a cycloaliphatic hydrocarbon group containing from 4 to 12 carbon atoms or an aromatic hydrocarbon group containing from 6 to 12 carbon atoms, b) one or more linking chains wherein each one of these linking chains links two of the structural units A; and c) a molecular weight in the range from 600 Daltons to 5000 Daltons.

##STR00001##

Claims

1. A multi-aziridine compound having: a) from 2 to 6 of the following structural units (A): ##STR00050## whereby R.sub.1 is H, R.sub.2 and R.sub.4 are independently chosen from H or an aliphatic hydrocarbon group containing from 1 to 4 carbon atoms, R.sub.3 is an aliphatic hydrocarbon group containing from 1 to 4 carbon atoms, R′═H or an aliphatic hydrocarbon group containing from 1 to 4 carbon atoms; R″ and R′″ are independently chosen from an aliphatic hydrocarbon group containing from 1 to 4 carbon atoms, a cycloaliphatic hydrocarbon group containing from 4 to 12 carbon atoms or an aromatic hydrocarbon group containing from 6 to 12 carbon atoms, whereby R′ (in case different than H) and R″ may be part of the same saturated cycloaliphatic hydrocarbon group containing from 4 to 8 carbon atoms, optionally containing heteroatoms, whereby R″ and R′″ may be part of the same saturated cycloaliphatic hydrocarbon group containing from 4 to 8 carbon atoms, optionally containing heteroatoms, b) one or more linking chains wherein each one of these linking chains links two of the structural units A; and c) a molecular weight in the range from 600 Daltons to 5000 Daltons, wherein the molecular weight is determined using MALDI-TOF mass spectrometry according to the description.

2. The multi-aziridine compound according to claim 1, wherein R.sub.2 is H, R.sub.3 is CH.sub.3 and R.sub.4 is H.

3. The multi-aziridine compound according to claim 1, wherein R.sub.2 is H, R.sub.3 is CH.sub.3 and R.sub.4 is CH.sub.3.

4. The multi-aziridine compound according to claim 1, wherein R′═H; R″ and R′″ are an aliphatic hydrocarbon group containing from 1 to 4 carbon atoms.

5. The multi-aziridine compound according to claim 1, wherein R′═H; R″ and R′″ are an aliphatic hydrocarbon group containing from 1 to 2 carbon atoms.

6. The multi-aziridine compound according to claim 1, wherein R′═H; R″ and R′″ are CH.sub.3.

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

8. The multi-aziridine compound 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.

9. The multi-aziridine compound according to claim 1, wherein the multi-aziridine compound has a molecular weight of from 840 to 3800 Daltons, whereby the molecular weight is determined using MALDI-TOF mass spectrometry according to the description.

10. The multi-aziridine compound 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, 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.

11. The multi-aziridine compound according to claim 10, 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.

12. The multi-aziridine compound 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: ##STR00051## 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.

13. The multi-aziridine compound according to claim 12, wherein X is O and R.sub.7 and R.sub.8 are H.

14. The multi-aziridine compound according to claim 12, wherein the multi-aziridine compound contains 2 structural units (A).

15. The multi-aziridine compound according to claim 14, 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.

16. The multi-aziridine compound 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.

17. The multi-aziridine compound 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: ##STR00052## 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 R′, R″, R′″, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are defined.

18. The multi-aziridine compound according to claim 17, wherein the polyisocyanate is a polyisocyanate with aliphatic reactivity.

19. The multi-aziridine compound according to claim 17, wherein compound B is obtained by reacting at least a non-OH functional monoepoxide compound with an aziridine compound with the following structural formula: ##STR00053## whereby R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are defined.

20. The multi-aziridine compound according to claim 19, wherein the non-OH functional monoepoxide compound is 2,2-dimethyloxirane (CAS number 558-30-5).

21. A crosslinker composition comprising at least one multi-aziridine compound according to claim 1 and further comprising at least one additional component.

22. The crosslinker composition according to claim 21, wherein the molecular weight of the multi-aziridine compounds present in the crosslinker composition is in the range from 600 Daltons to 5000 Daltons, whereby the molecular weight is determined using MALDI-TOF mass spectrometry according to the description.

23. The crosslinker composition according to claim 21, wherein the amount of aziridinyl group functional molecules having a molecular weight lower than 580 Daltons is lower than 5 wt. %, preferably lower than 2 wt. %, more preferably lower than 1 wt. %, more preferably lower than 0.5 wt. % and most preferably lower than 0.1 wt. %, relative to the total weight of the crosslinker composition, whereby the molecular weight is determined using LC-MS as described in the description.

24. The crosslinker composition according to claim 21, wherein the crosslinker composition contains less than 5 wt. % of water.

25. Use of the multi-aziridine compound according to claim 1 or the crosslinker composition for crosslinking 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.

26. A two-component coating system comprising a first component and a second component each of which is separate and distinct from each other and wherein the first component comprises a carboxylic acid functional polymer dissolved and/or dispersed, preferably 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 according to claim 1 or the crosslinker composition.

Description

EXAMPLE 1

[0103] A round bottom flask equipped with a condensor was placed under a N.sub.2 atmosphere and charged with propylene imine (10.02 gram), isobutylene oxide (10.04 gram) and K.sub.2CO.sub.3 (0.50 gram) and heated to 55° C., after which the mixture was stirred for 96 h at T=55° C. After filtration the excess of PI was removed in vacuo, followed by further purification via vacuum distillation, resulting in a colorless low viscous liquid.

[0104] 5.78 grams of the resulting material (2-methyl-1-(2-methylaziridin-1-yl)propan-2-ol) was charged to a feeding funnel together with 7.91 grams of dimethylformamide. This mixture was fed in 15 minutes to a reaction flask equipped with a thermometer and filled with a mixture of 9.00 grams of Desmodur® N 3600, 37.29 grams of DMF and 0.02 grams of bismuth neodecanoate that was heated to 50° C., while the mixture was stirred with a mechanical upper stirrer under a nitrogen atmosphere. After the feed was completed, 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, 0.29 grams of 1-butanol were added to the mixture, followed by further reaction to complete disappearance of aforementioned NCO-stretch peak. Concentration of the solution in vacuo to a 25 wt % solution yielded a slightly viscous liquid.

[0105] The calculated molecular weight of the theoretical main component was 891.62 Da, chemical structure is shown below.

##STR00026##

[0106] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+Na+]=914.62 Da; Obs. [M+Na+]=914.67 Da.

[0107] The following components with a mass below 580 Da were determined by LC-MS and quantified:

##STR00027##

was present in the composition at less than 0.01 wt % and

##STR00028##

was present at less than 0.01 wt. %.

[0108] 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, 1.4 parts of the crosslinker 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 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):

TABLE-US-00003 Sample 60 min 240 min Test 1-1 3 3 Test 1-2 1 1

[0109] Genotoxicity Test

TABLE-US-00004 Without S9 rat liver extract With S9 rat liver extract Bscl 2 Rtkn Bscl 2 Rtkn concentration .fwdarw. 10 25 50 10 25 50 10 25 50 10 25 50 Ex. 1 1.1 1.0 1.3 1.1 1.1 1.3 1.1 1.2 1.6 1.0 1.1 1.3

[0110] The genotoxicity test results show that the crosslinker composition of Example 1 only has weakly positive induced genotoxicity.

EXAMPLE 2

[0111] The (2-methyl-1-(2-methylaziridin-1-yl)propan-2-ol) intermediate was synthesized as described in Example 1.

[0112] 11.46 grams of the material (2-methyl-1-(2-methylaziridin-1-yl)propan-2-ol) was charged to a feeding funnel together with 25.2 grams of dimethylformamide. This mixture was fed in 30 minutes to a reaction flask equipped with a thermometer and filled with a mixture of 22.8 grams of Desmodur® N 3600, 72.0 grams of DMF and 0.002 grams of bismuth neodecanoate that was heated to 50° C., while the mixture was stirred with a mechanical upper stirrer under a nitrogen atmosphere. After the feed was completed, a mixture of 12.9 grams of a poly(ethylene glycol) monomethyl ether with an average Mn of 500 Da and 39.6 grams of DMF was added to the reaction mixture and stirred at 50° C. for 2 hours. Samples were taken at regular intervals and the reaction progress was monitored using a BrukerAlpha FT-IR spectrometer until no change in NCO-stretch at 2200-2300 cm.sup.−1 was observed. Subsequently, 0.48 grams of 1-butanol and 4.8 grams of DMF were added to the mixture, followed by further reaction to complete disappearance of aforementioned NCO-stretch peak. The reaction product was a slightly viscous 25 wt % solution of the crosslinker in DMF.

[0113] The calculated molecular weights of the theoretical main components were 891.62 Da (three aziridines), 1190.76 Da (two aziridines, 9 EG repeating units), 1234.79 Da (two aziridines, 10 EG repeating units) and 1278.81 Da (two aziridines, 11 EG repeating units), chemical structures are shown below.

##STR00029##

[0114] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+Na+]=914.62 Da; Obs. [M+Na+]=914.47 Da.

##STR00030##

[0115] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+Na+]=1213.76 Da; Obs. [M+Na+]=1213.59 Da.

##STR00031##

[0116] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+Na+]=1257.79 Da; Obs. [M+Na+]=1257.63 Da.

##STR00032##

[0117] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+Na+]=1301.81 Da; Obs. [M+Na+]=1301.67 Da.

[0118] The following components with a mass below 580 Da were determined by LC-MS and quantified:

##STR00033##

was present in the composition at less than 0.01 wt % and

##STR00034##

was present at less than 0.01 wt. %.

[0119] 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, 0.8 parts of the crosslinker 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 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):

TABLE-US-00005 Sample 60 min 240 min Test 2-1 4 3 Test 2-2 1 1

[0120] A waterborne acrylic binder was synthesized as follows.

[0121] 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 (174.41 grams), n-butyl acrylate (488.44 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.

[0122] For further spot tests, 1.6 parts of the crosslinker solution were added to 15 parts of the waterborne polyacrylate binder described above 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 (Test 2-4). The films were dried for 1 hour at 25° C., then annealed at 50° C. for 16 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):

TABLE-US-00006 Sample 60 min 240 min Test 2-3 3 3 Test 2-4 1 1

[0123] Genotoxicity Test

TABLE-US-00007 Without S9 rat liver extract With S9 rat liver extract Bscl 2 Rtkn Bscl 2 Rtkn concentration .fwdarw. 10 25 50 10 25 50 10 25 50 10 25 50 Ex. 2 1.1 1.4 1.7 1.1 1.1 1.1 1.1 1.5 1.6 1.1 1.1 1.1

[0124] The genotoxicity test results show that the crosslinker composition of Example 2 only has weakly positive induced genotoxicity.

EXAMPLE 3

[0125] A round bottom flask equipped with a condensor was placed under a N.sub.2 atmosphere and charged with propylene imine (25.2 gram), 2-methyl-2-vinyloxirane (24.7 gram) and K.sub.2CO.sub.3 (2.00 gram) and heated to 70° C., after which the mixture was stirred for 90 h at T=70° C. After filtration the excess of PI was removed in vacuo, followed by further purification via vacuum distillation, resulting in a colorless low viscous liquid.

[0126] 3.30 grams of the resulting material (2-methyl-1-(2-methylaziridin-1-yl)but-3-en-2-ol) was charged to a feeding funnel together with 11.0 grams of dimethylformamide. This mixture was fed in 15 minutes to a reaction flask equipped with a thermometer and filled with a mixture of 6.00 grams of Desmodur® N 3600, 22.0 grams of DMF and 0.12 grams of bismuth neodecanoate that was heated to 50° C., while the mixture was stirred with a mechanical upper stirrer under a nitrogen atmosphere. After the feed was completed, a mixture of 3.24 grams of a poly(ethylene glycol) monomethyl ether with an average Mn of 500 Da and 5.5 grams of DMF was added to the reaction mixture and stirred at 50° C. for 2 hours. 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, 0.19 grams of 1-butanol was added to the mixture, followed by further reaction to complete disappearance of aforementioned NCO-stretch peak. The reaction product was a slightly viscous 25 wt % solution of the crosslinker in DMF.

[0127] The calculated molecular weights of the theoretical main components were 941.63 Da (three aziridines), 1214.76 Da (two aziridines, 9 EG repeating units), 1258.79 Da (two aziridines, 10 EG repeating units) and 1302.81 Da (two aziridines, 11 EG repeating units), chemical structures are shown below.

##STR00035##

[0128] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+Na+]=950.61 Da; Obs. [M+Na+]=950.47 Da.

##STR00036##

[0129] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+Na+]=1237.76 Da; Obs. [M+Na+]=1237.56 Da.

##STR00037##

[0130] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+Na+]=1281.79 Da; Obs. [M+Na+]=1281.59 Da.

##STR00038##

[0131] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+Na+]=1325.81 Da; Obs. [M+Na+]=1325.61 Da.

[0132] The following components with a mass below 580 Da were determined by LC-MS and quantified:

##STR00039##

was present in the composition at less than 0.01 wt % and

##STR00040##

was present at less than 0.01 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, 1.1 parts of the crosslinker 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 3-1). For reference, films were also cast from the same composition lacking a crosslinker (Test 3-2). 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):

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

[0134] Genotoxicity Test

TABLE-US-00009 Without S9 rat liver extract With S9 rat liver extract Bscl 2 Rtkn Bscl 2 Rtkn concentration .fwdarw. 10 25 50 10 25 50 10 25 50 10 25 50 Ex. 3 1.1 1.4 1.7 1.0 1.1 1.2 1.1 1.6 1.9 1.3 1.3 1.5

[0135] The genotoxicity test results show that the crosslinker composition of Example 3 only has weakly positive induced genotoxicity.

EXAMPLE 4

[0136] The 2-methyl-1-(2-methylaziridin-1-yl)but-3-en-2-ol intermediate was synthesized as described in Example 3.

[0137] 3.30 grams of 2-methyl-1-(2-methylaziridin-1-yl)but-3-en-2-ol was charged to a feeding funnel together with 13.75 grams of dimethylformamide. This mixture was fed in 15 minutes to a reaction flask equipped with a thermometer and filled with a mixture of 6.00 grams of Desmodur® N 3600, 27.5 grams of DMF and 0.12 grams of bismuth neodecanoate that was heated to 50° C., while the mixture was stirred with a mechanical upper stirrer under a nitrogen atmosphere. After the feed was completed, a mixture of 6.52 grams of Jeffamine® XTJ-436 (CAS number 118270-87-4, obtained from Huntsman) and 6.88 grams of DMF was added to the reaction mixture and stirred at 50° C. for 2 hours. 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, 0.19 grams of 1-butanol was added to the mixture, followed by further reaction to complete disappearance of aforementioned NCO-stretch peak. The reaction product was a slightly viscous 25 wt % solution of the crosslinker in DMF.

[0138] The calculated molecular weights of the theoretical main components were 941.63 Da (three aziridines), 1644.16 Da (two aziridines, 11 PG repeating units), 1702.20 Da (two aziridines, 12 PG repeating units) and 1760.24 Da (two aziridines, 13 PG repeating units), chemical structures are shown below.

##STR00041##

[0139] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+Na+]=950.61 Da; Obs. [M+Na+]=950.49 Da.

##STR00042##

[0140] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+Na+]=1667.16 Da; Obs. [M+Na+]=1666.97 Da.

##STR00043##

[0141] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+Na+]=1725.20 Da; Obs. [M+Na+]=1725.01 Da.

##STR00044##

[0142] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+Na+]=1783.24 Da; Obs. [M+Na+]=1783.08 Da.

[0143] The following components with a mass below 580 Da were determined by LC-MS and quantified:

##STR00045##

was present in the composition at less than 0.01 wt % and

##STR00046##

was present at less than 0.01 wt. %.

[0144] 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, 1.4 parts of the crosslinker 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 4-1). For reference, films were also cast from the same composition lacking a crosslinker (Test 4-2). The films were dried for 16 hours at 25° C., then annealed at 50° C. for 1 hour and further dried of 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-00010 Sample 60 min 240 min Test 4-1 3 3 Test 4-2 1 1

[0145] Genotoxicity Test

TABLE-US-00011 Without S9 rat liver extract With S9 rat liver extract Bscl 2 Rtkn Bscl 2 Rtkn concentration .fwdarw. 10 25 50 10 25 50 10 25 50 10 25 50 Ex. 4 1.1 1.1 1.1 1.0 1.1 1.2 1.0 1.1 1.4 1.0 1.0 1.0

[0146] The genotoxicity test results show that the crosslinker composition of Example 4 is non-genotoxic.

EXAMPLE 5

[0147] The 2-methyl-1-(2-methylaziridin-1-yl)but-3-en-2-ol intermediate was synthesized as described in Example 3.

[0148] 5.09 grams of 2-methyl-1-(2-methylaziridin-1-yl)but-3-en-2-ol was charged to a feeding funnel together with 25.50 grams of dimethylformamide. This mixture was fed in 15 minutes to a reaction flask equipped with a thermometer and filled with a mixture of 7.00 grams of Desmodur® N 3900, 35.0 grams of DMF and 0.02 grams of bismuth neodecanoate that was heated to 50° C., while the mixture was stirred with a mechanical upper stirrer under a nitrogen atmosphere. After the feed was completed, the reaction mixture was stirred at 50° C. for 2 hours. Samples were taken at regular intervals and the reaction progress was monitored using a BrukerAlpha FT-IR spectrometer until no change in NCO-stretch at 2200-2300 cm.sup.−1 was observed. Subsequently, 0.23 grams of 1-butanol in 3.5 grams of DMF was added to the mixture, followed by further reaction to complete disappearance of aforementioned NCO-stretch peak. The reaction product was a slightly viscous 15 wt % solution of the crosslinker in DMF.

[0149] The calculated molecular weight of the theoretical main components was 941.63 Da, chemical structure is shown below.

##STR00047##

[0150] Molecular weight was confirmed by Maldi-TOF-MS: Calcd. [M+Na+]=950.61 Da; Obs. [M+Na+]=950.71 Da.

[0151] The following components with a mass below 580 Da were determined by LC-MS and quantified:

##STR00048##

was present in the composition at 0.011 wt % and

##STR00049##

was present at less than 0.01 wt. %.

[0152] 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, 0.7 parts of the crosslinker 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 5-1). For reference, films were also cast from the same composition lacking a crosslinker (Test 5-2). The films were dried for 16 hours at 25° C., then annealed at 50° C. for 1 hour and further dried of 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-00012 Sample 60 min 240 min Test 5-1 5 5 Test 5-2 1 1

[0153] A waterborne acrylic binder was synthesized as follows.

[0154] 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 (174.41 grams), n-butyl acrylate (488.44 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.

[0155] For further spot tests, 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, 1.3 parts of the crosslinker solution were added to 20 parts of the acrylic binder described above 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 5-3). For reference, films were also cast from the same composition lacking a crosslinker (Test 5-4). The films were dried for 16 hours at 25° C., then annealed at 50° C. for 1 hour and further dried of 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-00013 Sample 60 min 240 min Test 5-3 4 4 Test 5-4 1 1

[0156] Genotoxicity Test

TABLE-US-00014 Without S9 rat liver extract With S9 rat liver extract Bscl 2 Rtkn Bscl 2 Rtkn concentration .fwdarw. 10 25 50 10 25 50 10 25 50 10 25 50 Ex. 5 1.3 1.5 1.7 1.0 1.0 1.1 1.2 1.4 1.7 1.1 1.3 1.4

[0157] The genotoxicity test results show that the crosslinker composition of Example 5 only has weakly positive induced genotoxicity.