Polyaspartic acid ester compositions which contain polyaspartic acid esters with primary amino groups and small amounts of fumaric acid dialkyl esters

Abstract

The present invention relates to polyaspartic acid ester compositions which contain polyaspartic acid esters with primary amino groups and small amounts of fumaric acid dialkyl esters, to a method for preparing same and the use thereof as a reactive component for polyisocyanates in two-component polyurethane systems.

Claims

1. A polyaspartic ester composition comprising one or more polyaspartic esters of the general formula (I) ##STR00021## in which X is an m-valent organic radical, optionally containing one or more heteroatoms obtained by removing the primary amino groups from a corresponding polyamine that has (cyclo)aliphatically or araliphatically attached amino groups and is in the molecular weight range from 60 to 6000 g/mol, and which comprises further functional groups that are reactive toward isocyanate groups and/or inert at temperatures of up to 100° C., R1 and R2 are identical or different organic radicals each having 1 to 18 carbon atoms, m is an integer >1, and one or more polyaspartic esters having a primary amino group that are of the general formula (II) ##STR00022## in which n is m−1, X and radicals R1 and R2 have the meanings defined for the polyaspartic esters of the general formula (I), wherein a proportion of the polyaspartic esters of the general formula (II) corresponds to from 4% to 15% of a total GC surface area of the composition measured by gas chromatogram as area-%, wherein the total GC surface area is a sum of the individual surface areas of the polyaspartic esters of the general formulas (I) and (II) and is equal to 100%, and wherein the composition comprises dialkyl fumarate in a proportion of 0.01 to 1% by weight.

2. A process for producing the polyaspartic ester composition of claim 1 comprising: combining one or more polyaspartic esters of the general formula (I) ##STR00023## in which X is an m-valent organic radical, optionally containing one or more heteroatoms obtained by removing the primary amino groups from a corresponding polyamine that has (cyclo)aliphatically or araliphatically attached amino groups and is in the molecular weight range from 60 to 6000 g/mol, and which comprises further functional groups that are reactive toward isocyanate groups and/or inert at temperatures of up to 100° C., R1 and R2 are identical or different organic radicals, preferably identical or different alkyl radicals each having 1 to 18 carbon atoms, m is an integer >1, with one or more polyaspartic esters having a primary amino group that are of the general formula (II) ##STR00024## in which n is m−1, X and radicals R1 and R2 have the meanings defined for the polyaspartic esters of the general formula (I), produced by reacting polyamines of the general formula (III), ##STR00025## in which X and m have the meaning defined for the polyaspartic esters of the general formula (I), with compounds of the general formula (IV)
R1OOC—CH═CH—COOR2  (IV), in which the radicals R1 and R2 have the meaning defined for the polyaspartic esters of the general formula (I); and removing an unreacted proportion of the compound of the general formula (IV) by distillation, wherein the polyaspartic ester composition comprises a proportion of the polyaspartic ester of the general formula (II) of 4% to 15% of a total GC surface area measured by gas chromatogram as area-%, wherein the total GC surface area is a sum of the individual surface areas of the polyaspartic esters of the general formulas (I) and (II) and is equal to 100%, and wherein the composition comprises dialkyl fumarate in a proportion of 0.01 to 1% by weight.

3. A two-component polyurethane system, comprising the polyaspartic ester composition of claim 1 and a reactive component that is reactive towards the polyaspartic ester composition of claim 1.

4. A substrate coated with a polyaspartic ester composition as claimed in claim 1.

5. A prepolymer, comprising a reaction product of the polyaspartic ester composition of claim 1 with a reactive component that is reactive towards the polyaspartic ester composition of claim 1.

6. The polyaspartic ester composition of claim 1, wherein the composition has a platinum-cobalt color index of 5≤25.

Description

DETAILED DESCRIPTION

(1) Preference is given to the polyaspartic ester compositions according to the invention in which R1 and R2 are identical or different alkyl radicals each having 1 to 18 carbon atoms, preferably identical or different alkyl radicals each having 1 to 8 carbon atoms and most preferably in each case alkyl radicals such as methyl, ethyl, propyl, isopropyl, butyl or isobutyl radicals. Very particular preference is given to ethyl.

(2) Polyaspartic ester compositions according to the invention are those in which X is organic radicals obtained by removing the primary amino groups from a corresponding (cyclo)aliphatically or araliphatically attached polyamine having primary amino groups, selected from the following group: all known polyamines having primary amino groups that conform to the general formula (III). Examples include the following compounds: ethylenediamine, 1,2-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 2,5-diamino-2,5-dimethylhexane, 1,5-diamino-2-methylpentane (Dytek®A, DuPont), 1,6-diaminohexane, 2,2,4- and/or 2,4,4-trimethyl-1,6-diaminohexane, 1,11-diaminoundecane, 1,12-diaminododecane or triaminononane, etheramines such as 4,9-dioxadodecane-1,12-diamine, 4,7,10-trioxatridecane-1,13-diamine or higher-molecular-weight polyether polyamines having aliphatically attached primary amino groups, for example those marketed under the Jeffamine® name by Huntsman. Also employable are aliphatic polycyclic polyamines such as tricyclodecanebismethylamine (TCD diamine) or bis(aminomethyl)norbornanes, amino-functional siloxanes, for example diaminopropylsiloxane G10 DAS (from Momentive), oleoalkyl-based amines, for example Fentamine from Solvay, dimeric fatty acid diamines such as Priamine from Croda.

(3) Preference is given to the polyaspartic ester compositions according to the invention in which X is organic radicals obtained by removing the primary amino groups from one of the polyamines of the general formula (III) in which m=2 and X is a cyclic hydrocarbon radical containing at least one cyclic carbon ring. Examples of diamines usable with particular preference are 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane (IPDA), 2,4- and/or 2,6-hexahydrotolylenediamine (H6-TDA), isopropyl-2,4-diaminocyclohexane and/or isopropyl-2,6-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 2,4′-, and/or 4,4′-diaminodicyclohexylmethane, 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane (Laromin® C 260, BASF AG), the isomeric diaminodicyclohexylmethanes substituted in the ring with a methyl group (═C-monomethyl-diaminodicyclohexylmethanes), 3(4)-aminomethyl-1-methylcyclohexylamine (AMCA), and also araliphatic diamines such as 1,3-bis(aminomethyl)benzene or m-xylylenediamine.

(4) Likewise preferred are the polyaspartic ester compositions according to the invention in which X is organic radicals obtained by removing the primary amino groups from one of the polyamines of the general formula (III) selected from the following group: polyether polyamines having aliphatically attached primary amino groups, 1,2-diaminopropane, 1,4-diaminobutane, 1,6-diaminohexane, 1,5-diamino-2-methylpentane, 2,5-diamino-2,5-dimethylhexane, 2,2,4- and/or 2,4,4-trimethyl-1,6-diaminohexane, 1,11-diaminoundecane, 1,12-diaminododecane, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane, 2,4- and/or 2,6-hexahydrotolylenediamine, 1,5-diaminopentane, 2,4′- and/or 4,4′-diaminodicyclohexylmethane or 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane.

(5) Particular preference is given to 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, 1,5-diaminopentane, 2,4′- and/or 4,4′-diaminodicyclohexylmethane, 1,5-diamino-2-methylpentane, and very particular preference to the use of 2,4′- and/or 4,4′-diaminodicyclohexylmethane.

(6) Particular preference is given to the polyaspartic ester compositions according to the invention in which X is organic radicals obtained by removing the primary amino groups from one of the polyamines of the general formula (III) selected from the following group: polyether polyamines having aliphatically attached primary amino groups, 1,2-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,5-diamino-2-methylpentane, 2,5-diamino-2,5-dimethylhexane, 2,2,4- and/or 2,4,4-trimethyl-1,6-diaminohexane, 1,11-diaminoundecane, 1,12-diaminododecane, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane, 2,4- and/or 2,6-hexahydrotolylenediamine, 2,4′- and/or 4,4′-diaminodicyclohexylmethane or 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane.

(7) Most preferred are the polyaspartic ester compositions according to the invention in which X is organic radicals obtained by removing the primary amino groups from one of the polyamines of the general formula (III) selected from the following group: 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, 2,4′- and/or 4,4′-diaminodicyclohexylmethane, 1,5-diamino-2-methylpentane.

(8) Preferably, m is an integer >1 and is more preferably 2.

(9) Preference is given to the polyaspartic ester compositions according to the invention containing a proportion of 1% to 20%, preferably 4% to 20%, more preferably up to 4% to 15%, of the GC surface area (measured as area-% in the gas chromatogram) of the compound of the general (II) corresponds, wherein the sum of the GC surface areas of the two compounds of the general formula (I) and (II) is 100%.

(10) Preference is given to the polyaspartic ester compositions according to the invention containing a proportion of 0.01 to 3% by weight, preferably 0.01 to 1% by weight, more preferably 0.01 to 0.1% by weight, of dialkyl fumarate.

(11) Preference is likewise given to the polyaspartic ester compositions according to the invention containing a proportion of 0.01 to 0.99% by weight of dialkyl fumarate.

(12) The present invention particularly preferably provides a composition comprising one or more polyaspartic esters of the general formula (I),

(13) in which

(14) X is an m-valent organic radical optionally containing one or more heteroatoms, as obtained by removing primary amino groups from polyether polyamines having aliphatically attached primary amino groups, 1,2-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,5-diamino-2-methylpentane, 2,5-diamino-2,5-dimethylhexane, 2,2,4- and/or 2,4,4-trimethyl-1,6-diaminohexane, 1,11-diaminoundecane, 1,12-diaminododecane, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane, 2,4- and/or 2,6-hexahydrotolylenediamine, 2,4′- and/or 4,4′-diaminodicyclohexylmethane or 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, R1 and R2 are identical or different alkyl radicals each having 1 to 8 carbon atoms, m is an integer >1, and
one or more polyaspartic esters having a primary amino group that are of the general formula (II), in which n is m−1, X and radicals R1 and R2 have the meanings defined above,

(15) characterized in that the proportion of the compound of the general formula (II) corresponds to from 4% to 20% of the GC surface area (measured as area-% in the gas chromatogram), wherein the sum of the GC surface areas of the two compounds of the general formula (I) and (II) is 100% and dialkyl fumarate is present in a proportion of 0.01 to 1% by weight.

(16) The present invention most preferably provides a composition comprising one or more polyaspartic esters of the general formula (I), in which X is an m-valent organic radical as can be obtained by removing primary amino groups from 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, 2,4′- and/or 4,4′-diaminodicyclohexylmethane, 1,5-diamino-2-methylpentane, R1 and R2 are identical or different alkyl radicals selected from the group consisting of methyl, ethyl, propyl, isopropyl, butyl or isobutyl radicals, m is 2,
and
one or more polyaspartic esters having primary amino groups of the general formula (II), in which n is m−1, X and radicals R1 and R2 have the meanings defined above,

(17) characterized in that the proportion of the compound of the general formula (II) corresponds to from 4% to 15% of the GC surface area (measured as area-% in the gas chromatogram), wherein the sum of the GC surface areas of the two compounds of the general formula (I) and (II) is 100% and dialkyl fumarate is present in a proportion of 0.01 to 0.1% by weight.

(18) The present invention particularly preferably further provides a composition comprising one or more polyaspartic esters of the general formula

(19) (I),

(20) in which

(21) X is an m-valent organic radical as can be obtained by removing primary amino groups from 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, 2,4′- and/or 4,4′-diaminodicyclohexylmethane, R1 and R2 are ethyl radicals, m is 2,
and
one or more polyaspartic esters having a primary amino group that are of the general formula (II), in which n is m−1, X and radicals R1 and R2 have the meanings defined above,

(22) characterized in that the proportion of the compound of the general formula (II) corresponds to from 4% to 15% of the GC surface area (measured as area-% in the gas chromatogram), the proportion of the two compounds of the general formula (I) and (II), wherein the sum of the GC surface areas of the two compounds of the general formula (I) and (II) is 100% and dialkyl fumarate is present in a proportion of 0.01 to 0.1% by weight.

(23) The present invention particularly preferably further provides a composition comprising one or more polyaspartic esters of the general formula (I)

(24) ##STR00003##
in which X is an m-valent organic radical, optionally containing one or more heteroatoms, as can be obtained by removing the primary amino groups from a corresponding polyamine that has (cyclo)aliphatically or araliphatically attached amino groups and is in the molecular weight range from 60 to 6000 g/mol, and which may contain further functional groups that are reactive toward isocyanate groups and/or inert at temperatures of up to 100° C., R1 and R2 are identical or different organic radicals each having 1 to 18 carbon atoms, m is an integer >1,
and
one or more polyaspartic esters having primary amino groups of the general formula (II)

(25) ##STR00004##
in which n is m−1, X and radicals R1 and R2 have the meanings defined above,

(26) characterized in that the proportion of the compound of the general formula (II) corresponds to from 4% to 15% of the GC surface area (measured as area-% in the gas chromatogram), wherein the sum of the GC surface areas of the two compounds of the general formula (I) and (II) is 100% and dialkyl fumarate is present in a proportion of 0.01 to 1% by weight.

(27) The present invention particularly preferably further provides a composition comprising one or more polyaspartic esters of the general formula (I)

(28) ##STR00005##
in which X is an m-valent organic radical, optionally containing one or more heteroatoms, as can be obtained by removing the primary amino groups from a corresponding polyamine that has (cyclo)aliphatically or araliphatically attached amino groups and is in the molecular weight range from 60 to 6000 g/mol, and which may contain further functional groups that are reactive toward isocyanate groups and/or inert at temperatures of up to 100° C., R1 and R2 are identical or different organic radicals each having 1 to 18 carbon atoms, m is an integer >1,
and
one or more polyaspartic esters having primary amino groups of the general formula (II)

(29) ##STR00006##
in which n is m−1, X and radicals R1 and R2 have the meanings defined above,

(30) characterized in that the proportion of the compound of the general formula (II) corresponds to from 4% to 15% of the GC surface area (measured as area-% in the gas chromatogram), the proportion of the two compounds of the general formula (I) and (II), wherein the sum of the GC surface areas of the two compounds of the general formula (I) and (II) is 100% and dialkyl fumarate is present in a proportion of 0.01 to 0.99% by weight.

(31) Preference is given to polyaspartic ester compositions according to the invention that have a platinum-cobalt color index of ≤100, more preferably ≤50. The platinum-cobalt color index is measured in accordance with DIN EN ISO 6271:2016-05.

(32) The invention further provides a process for producing the composition comprising one or more polyaspartic esters of the general formula (I)

(33) ##STR00007##
in which X is an m-valent organic radical, optionally containing one or more heteroatoms, as can be obtained by removing the primary amino groups from a corresponding polyamine that has (cyclo)aliphatically or araliphatically attached amino groups and is in the molecular weight range from 60 to 6000 g/mol, and which may contain further functional groups that are reactive toward isocyanate groups and/or inert at temperatures of up to 100° C., R1 and R2 are identical or different organic radicals, preferably identical or different alkyl radicals each having 1 to 18 carbon atoms, and most preferably identical or different alkyl radicals each having 1 to 8 carbon atoms, m is an integer >1,
and
one or more polyaspartic esters having a primary amino group that are of the general formula (II)

(34) ##STR00008##
in which n is m−1, X and radicals R1 and R2 have the meanings defined above,
produced by reacting polyamines of the general formula (III),

(35) ##STR00009##
in which X and m have the meaning defined above,
with compounds of the general formula (IV)
R1OOC—CH═CH—COOR2  (IV),
in which the radicals R1 and R2 have the meaning defined above,
and removal by distillation of the unreacted proportion of the compound of the general formula (IV),

(36) characterized in that the resulting polyaspartic ester composition contains a proportion of the compound of the general formula (II) of from 1% to 20% of the GC surface area (measured as area-% in the gas chromatogram), which corresponds to the proportion of the two compounds of the general formula (I) and (II), wherein the sum of the GC surface areas of the two compounds of the general formula (I) and (II) is 100%, and dialkyl fumarate in a proportion of 0.01 to 3% by weight.

(37) The present invention preferably further provides the process disclosed above for producing the composition comprising one or more polyaspartic esters of the general formula (I), in which X is an m-valent organic radical, optionally containing one or more heteroatoms, as obtained by removing primary amino groups from polyether polyamines having aliphatically attached primary amino groups, 1,2-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,5-diamino-2-methylpentane, 2,5-diamino-2,5-dimethylhexane, 2,2,4- and/or 2,4,4-trimethyl-1,6-diaminohexane, 1,11-diaminoundecane, 1,12-diaminododecane, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane, 2,4- and/or 2,6-hexahydrotolylenediamine, 2,4′- and/or 4,4′-diamino-dicyclohexylmethane or 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, R1 and R2 are identical or different alkyl radicals each having 1 to 8 carbon atoms, m is an integer >1,
and
one or more polyaspartic esters having a primary amino group that are of the general formula (II), in which n is m−1, X and radicals R1 and R2 have the meanings defined above,

(38) produced by reacting polyamines of the general formula (III), in which X and m have the meaning defined above, with compounds of the general formula (IV), in which the radicals R1 and R2 have the meaning defined above

(39) and removal by distillation of the unreacted proportion of the compound of the general formula (IV),

(40) characterized in that the resulting polyaspartic ester composition contains a proportion of the compound of the general formula (II) of from 4% to 20% of the GC surface area (measured as area-% in the gas chromatogram), which corresponds to the proportion of the two compounds of the general formula (I) and (II), wherein the sum of the GC surface areas of the two compounds of the general formula (I) and (II) is 100%, and dialkyl fumarate in a proportion of 0.01 to 1% by weight.

(41) The present invention preferably further provides the process disclosed above for producing the composition comprising one or more polyaspartic esters of the general formula (I), in which X is an m-valent organic radical as can be obtained by removing primary amino groups from 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, 2,4′- and/or 4,4′-diaminodicyclohexylmethane, 1,5-diamino-2-methylpentane, R1 and R2 are identical or different alkyl radicals selected from the group consisting of methyl, ethyl, propyl, isopropyl, butyl or isobutyl radicals, m is 2,
and
one or more polyaspartic esters having a primary amino group that are of the general formula (II), in which n is m−1, X and radicals R1 and R2 have the meanings defined above,

(42) produced by reacting polyamines of the general formula (III), in which X and m have the meaning defined above, with compounds of the general formula (IV), in which the radicals R1 and R2 have the meaning defined above

(43) and removal by distillation of the unreacted proportion of the compound of the general formula (IV),

(44) characterized in that the resulting polyaspartic ester composition contains a proportion of the compound of the general formula (II) of from 4% to 15% of the GC surface area (measured as area-% in the gas chromatogram), which corresponds to the proportion of the two compounds of the general formula (I) and (II), wherein the sum of the GC surface areas of the two compounds of the general formula (I) and (II) is 100%, and dialkyl fumarate in a proportion of 0.01 to 0.1% by weight.

(45) The invention preferably further provides a process for producing the composition comprising one or more polyaspartic esters of the general formula (I)

(46) ##STR00010##
in which X is an m-valent organic radical, optionally containing one or more heteroatoms, as can be obtained by removing the primary amino groups from a corresponding polyamine that has (cyclo)aliphatically or araliphatically attached amino groups and is in the molecular weight range from 60 to 6000 g/mol, and which may contain further functional groups that are reactive toward isocyanate groups and/or inert at temperatures of up to 100° C., R1 and R2 are identical or different organic radicals, preferably identical or different alkyl radicals each having 1 to 18 carbon atoms, and most preferably identical or different alkyl radicals each having 1 to 8 carbon atoms, m is an integer >1,
and
one or more polyaspartic esters having a primary amino group that are of the general formula (II)

(47) ##STR00011##
in which n is m−1, X and radicals R1 and R2 have the meanings defined above,
produced by reacting polyamines of the general formula (III),

(48) ##STR00012##
in which X and m have the meaning defined above,
with compounds of the general formula (IV)
R1OOC—CH═CH—COOR2  (IV),
in which the radicals R1 and R2 have the meaning defined above,

(49) and removal by distillation of the unreacted proportion of the compound of the general formula (IV),

(50) characterized in that the resulting polyaspartic ester composition contains a proportion of the compound of the general formula (II) of from 4% to 15% of the GC surface area (measured as area-% in the gas chromatogram), which corresponds to the proportion of the two compounds of the general formula (I) and (II), wherein the sum of the GC surface areas of the two compounds of the general formula (I) and (II) is 100%, and dialkyl fumarate in a proportion of 0.01 to 1% by weight.

(51) The invention preferably further provides a process for producing the composition comprising one or more polyaspartic esters of the general formula (I)

(52) ##STR00013##
in which X is an m-valent organic radical, optionally containing one or more heteroatoms, as can be obtained by removing the primary amino groups from a corresponding polyamine that has (cyclo)aliphatically or araliphatically attached amino groups and is in the molecular weight range from 60 to 6000 g/mol, and which may contain further functional groups that are reactive toward isocyanate groups and/or inert at temperatures of up to 100° C., R1 and R2 are identical or different organic radicals, preferably identical or different alkyl radicals each having 1 to 18 carbon atoms, and most preferably identical or different alkyl radicals each having 1 to 8 carbon atoms, m is an integer >1,
and
one or more polyaspartic esters having a primary amino group that are of the general formula (II)

(53) ##STR00014##
in which n is m−1, X and radicals R1 and R2 have the meanings defined above,
produced by reacting polyamines of the general formula (III),

(54) ##STR00015##
in which X and m have the meaning defined above,
with compounds of the general formula (IV)
R1OOC—CH═CH—COOR2  (IV),
in which the radicals R1 and R2 have the meaning defined above,

(55) and removal by distillation of the unreacted proportion of the compound of the general formula (IV),

(56) characterized in that the resulting polyaspartic ester composition contains a proportion of the compound of the general formula (II) of 4% to 15% of the GC surface area (measured as area-% in the gas chromatogram), wherein the sum of the GC surface areas of the two compounds of the general formula (I) and (II) is 100%, and contains dialkyl fumarate in a proportion of 0.01 to 0.99% by weight.

(57) The present invention preferably further provides the process disclosed above for producing the composition comprising one or more polyaspartic esters of the general formula (I), in which X is an m-valent organic radical, as can be obtained by removing primary amino groups from 2,4′- and/or 4,4′-diaminodicyclohexylmethane, R1 and R2 are ethyl radicals, m is 2,
and
one or more polyaspartic esters having a primary amino group that are of the general formula (II), in which n is m−1, X and radicals R1 and R2 have the meanings defined above,

(58) produced by reacting polyamines of the general formula (III), in which X and m have the meaning defined above, with compounds of the general formula (IV), in which the radicals R1 and R2 have the meaning defined above

(59) and removal by distillation of the unreacted proportion of the compound of the general formula (IV),

(60) characterized in that the resulting polyaspartic ester composition contains a proportion of the compound of the general formula (II) of 4% to 15% of the GC surface area (measured as area-% in the gas chromatogram), corresponds, wherein the sum of the GC surface areas of the two compounds of the general formula (I) and (II) is 100%, and dialkyl fumarate in a proportion of 0.01 to 0.1% by weight.

(61) The present invention further provides a composition comprising one or more polyaspartic esters of the general formula (I)

(62) ##STR00016##
in which X is an m-valent organic radical, optionally containing one or more heteroatoms, as can be obtained by removing the primary amino groups from a corresponding polyamine that has (cyclo)aliphatically or araliphatically attached amino groups and is in the molecular weight range from 60 to 6000 g/mol, and which may contain further functional groups that are reactive toward isocyanate groups and/or inert at temperatures of up to 100° C., R1 and R2 are identical or different organic radicals each having 1 to 18 carbon atoms, m is an integer >1,
and
one or more polyaspartic esters having a primary amino group that are of the general formula (II)

(63) ##STR00017##
in which n is m−1, X and radicals R1 and R2 have the meanings defined above,

(64) characterized in that the proportion of the compound of the general formula (II) corresponds to from 1% to 20% of the GC surface area (measured as area-% in the gas chromatogram), the proportion of the two compounds of the general formula (I) and (II), wherein the sum of the GC surface areas of the two compounds of the general formula (I) and (II) is 100% and dialkyl fumarate is present in a proportion of 0.01 to 3% by weight.

(65) Preference is given to the polyaspartic ester compositions according to the invention containing a proportion of 1% to 20%, preferably 4% to 20%, more preferably up to 4% to 15%, of the GC surface area (measured as area-% in the gas chromatogram) of the two compounds of the general formula (II) and (III) corresponds, wherein the sum of the GC surface areas of the two compounds of the general formula (I) and (II) is 100%.

(66) The present invention particularly preferably and further provides a composition comprising one or more polyaspartic esters of the general formula (I),

(67) in which

(68) X is an m-valent organic radical optionally containing one or more heteroatoms, as obtained by removing primary amino groups from polyether polyamines having aliphatically attached primary amino groups, 1,2-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,5-diamino-2-methylpentane, 2,5-diamino-2,5-dimethylhexane, 2,2,4- and/or 2,4,4-trimethyl-1,6-diaminohexane, 1,11-diaminoundecane, 1,12-diaminododecane, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane, 2,4- and/or 2,6-hexahydrotolylenediamine, 2,4′- and/or 4,4′-diaminodicyclohexylmethane or 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, R1 and R2 are identical or different alkyl radicals each having 1 to 8 carbon atoms, m is an integer >1,
and
one or more polyaspartic esters having primary amino groups of the general formula (II), in which n is m−1, X and radicals R1 and R2 have the meanings defined above,

(69) characterized in that the proportion of the compound of the general formula (II) corresponds to from 4% to 20% of the GC surface area (measured as area-% in the gas chromatogram), the proportion of the two compounds of the general formula (I) and (II), wherein the sum of the GC surface areas of the two compounds of the general formula (I) and (II) is 100% and dialkyl fumarate is present in a proportion of 0.01 to 1% by weight.

(70) The present invention most preferably and further provides a composition comprising one or more polyaspartic esters of the general formula (I), in which X is an m-valent organic radical as can be obtained by removing primary amino groups from 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, 2,4′- and/or 4,4′-diaminodicyclohexylmethane, 1,5-diamino-2-methylpentane, R1 and R2 are identical or different alkyl radicals selected from the group consisting of methyl, ethyl, propyl, isopropyl, butyl or isobutyl radicals, m is 2,
and
one or more polyaspartic esters having primary amino groups of the general formula (II), in which n is m−1, X and radicals R1 and R2 have the meanings defined above,

(71) characterized in that the proportion of the compound of the general formula (II) corresponds to from 4% to 15% of the GC surface area (measured as area-% in the gas chromatogram), the proportion of the two compounds of the general formula (I) and (II), wherein the sum of the GC surface areas of the two compounds of the general formula (I) and (II) is 100% and dialkyl fumarate is present in a proportion of 0.01 to 0.1% by weight.

(72) The present invention particularly preferably further provides a composition comprising one or more polyaspartic esters of the general formula

(73) (I),

(74) in which

(75) X is an m-valent organic radical as can be obtained by removing primary amino groups from 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, 2,4′- and/or 4,4′-diaminodicyclohexylmethane, R1 and R2 are ethyl radicals, m is 2,
and
one or more polyaspartic esters having a primary amino group that are of the general formula (II), in which n is m−1, X and radicals R1 and R2 have the meanings defined above,

(76) characterized in that the proportion of the compound of the general formula (II) corresponds to from 4% to 15% of the GC surface area (measured as area-% in the gas chromatogram), the proportion of the two compounds of the general formula (I) and (II), wherein the sum of the GC surface areas of the two compounds of the general formula (I) and (II) is 100% and dialkyl fumarate is present in a proportion of 0.01 to 0.1% by weight.

(77) The invention further provides a process for producing the composition comprising one or more polyaspartic esters of the general formula (I)

(78) ##STR00018##
in which X is an m-valent organic radical, optionally containing one or more heteroatoms, as can be obtained by removing the primary amino groups from a corresponding polyamine that has (cyclo)aliphatically or araliphatically attached amino groups and is in the molecular weight range from 60 to 6000 g/mol, and which may contain further functional groups that are reactive toward isocyanate groups and/or inert at temperatures of up to 100° C., R1 and R2 are identical or different organic radicals, preferably identical or different alkyl radicals each having 1 to 18 carbon atoms, and most preferably identical or different alkyl radicals each having 1 to 8 carbon atoms, m is an integer >1,
and
one or more polyaspartic esters having a primary amino group that are of the general formula (II)

(79) ##STR00019##
in which n is m−1, X and radicals R1 and R2 have the meanings defined above,
produced by reacting polyamines of the general formula (III),

(80) ##STR00020##
in which X and m have the meaning defined above,
with compounds of the general formula (IV)
R1OOC—CH═CH—COOR2  (IV),
in which the radicals R1 and R2 have the meaning defined above,

(81) characterized in that the resulting polyaspartic ester composition contains a proportion of the compound of the general formula (II) of from 1% to 20% of the GC surface area (measured as area-% in the gas chromatogram), which corresponds to the proportion of the two compounds of the general formula (I) and (II), wherein the sum of the GC surface areas of the two compounds of the general formula (I) and (II) is 100%, and dialkyl fumarate in a proportion of 0.01 to 3% by weight.

(82) The present invention preferably further provides the process disclosed above for producing the composition comprising one or more polyaspartic esters of the general formula (I), in which X is an m-valent organic radical, optionally containing one or more heteroatoms, as obtained by removing primary amino groups from polyether polyamines having aliphatically attached primary amino groups, 1,2-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,5-diamino-2-methylpentane, 2,5-diamino-2,5-dimethylhexane, 2,2,4- and/or 2,4,4-trimethyl-1,6-diaminohexane, 1,11-diaminoundecane, 1,12-diaminododecane, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane, 2,4- and/or 2,6-hexahydrotolylenediamine, 2,4′- and/or 4,4′-diaminodicyclohexylmethane or 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, R1 and R2 are identical or different alkyl radicals each having 1 to 8 carbon atoms, m is an integer >1,
and
one or more polyaspartic esters having a primary amino group that are of the general formula (II), in which n is m−1, X and radicals R1 and R2 have the meanings defined above,

(83) produced by reacting polyamines of the general formula (III), in which X and m have the meaning defined above, with compounds of the general formula (IV), in which the radicals R1 and R2 have the meaning defined above,

(84) characterized in that the resulting polyaspartic ester composition contains a proportion of the compound of the general formula (II) of from 4% to 20% of the GC surface area (measured as area-% in the gas chromatogram), which corresponds to the proportion of the two compounds of the general formula (I) and (II), wherein the sum of the GC surface areas of the two compounds of the general formula (I) and (II) is 100%, and dialkyl fumarate in a proportion of 0.01 to 1% by weight.

(85) The present invention preferably further provides the process disclosed above for producing the composition comprising one or more polyaspartic esters of the general formula (I), in which X is an m-valent organic radical, as can be obtained by removing primary amino groups from 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, 2,4′- and/or 4,4′-diaminodicyclohexylmethane, 1,5-diamino-2-methylpentane, R1 and R2 are identical or different alkyl radicals selected from the group consisting of methyl, ethyl, propyl, isopropyl, butyl or isobutyl radicals, m is 2,
and
one or more polyaspartic esters having a primary amino group that are of the general formula (II), in which n is m−1, X and radicals R1 and R2 have the meanings defined above,

(86) produced by reacting polyamines of the general formula (III), in which X and m have the meaning defined above, with compounds of the general formula (IV), in which the radicals R1 and R2 have the meaning defined above,

(87) characterized in that the resulting polyaspartic ester composition contains a proportion of the compound of the general formula (II) of from 4% to 15% of the GC surface area (measured as area-% in the gas chromatogram), which corresponds to the proportion of the two compounds of the general formula (I) and (II), wherein the sum of the GC surface areas of the two compounds of the general formula (I) and (II) is 100%, and dialkyl fumarate in a proportion of 0.01 to 0.1% by weight.

(88) The present invention preferably further provides the process disclosed above for producing the composition comprising one or more polyaspartic esters of the general formula (I), in which X is an m-valent organic radical as can be obtained by removing primary amino groups from 2,4′- and/or 4,4′-diaminodicyclohexylmethane, R1 and R2 are ethyl radicals, m is 2,
and
one or more polyaspartic esters having a primary amino group that are of the general formula (II), in which n is m−1, X and radicals R1 and R2 have the meanings defined above,

(89) produced by reacting polyamines of the general formula (III), in which X and m have the meaning defined above, with compounds of the general formula (IV), in which the radicals R1 and R2 have the meaning defined above,

(90) characterized in that the resulting polyaspartic ester composition contains a proportion of the compound of the general formula (II) of 4% to 15% of the GC surface area (measured as area-% in the gas chromatogram) that corresponds to the proportion of the two compounds of the general formula (I) and (II), wherein the sum of the GC surface areas of the two compounds of the general formula (I) and (II) is 100%, and dialkyl fumarate in a proportion of 0.01 to 0.1% by weight.

(91) The process according to the invention for producing the composition comprising polyaspartic esters of the general formula (I) and one or more polyaspartic esters having primary amino groups of the general formula (II) is preferably carried out in two steps. In the first step, the compounds of the general formula (III) and (IV) are reacted at temperatures between 0° C. and 100° C., preferably 20 to 80° C., and more preferably 20 to 60° C., in a ratio of equivalents of primary amino groups in the compounds of the general formula (III) to C═C double bond equivalents in the compounds of the general formula (IV) of 1:1.2 to 1.2:1, but preferably 1:1.05 to 1.05:1, until the residual content of compounds of the general formula (IV) is from 2 to 15% by weight, preferably from 3 to 10% by weight.

(92) In the second step, the unreacted fraction of the compounds of the general formula (IV) is removed by distillation.

(93) Suitable conditions during the distillation are a pressure range between 0.01 and 2 mbar and a temperature of the bottom outflow on exiting the distillation apparatus of ≤170° C. and ≥ the temperature resulting from the following formula (V):
T(bottom outflow)=27×ln(p)+150  (V) where T(bottom outflow) is the temperature of the bottom outflow in ° C. and p is the pressure in the distillation apparatus in mbar.

(94) Maintaining this pressure range ensures not only that moderate temperatures in the bottom outflow are sufficient for depletion of the dialkyl fumarate content to the desired degree, but that the process remains usable on an industrial scale. At lower pressure, the gas density becomes too low and the necessary equipment items consequently so large that the process becomes disadvantageous from an economic viewpoint.

(95) The temperature of the bottom outflow is preferably ≤170° C., but at least 20 K above the temperature resulting from formula (V); more preferably it is between 20 K and 40 K above the temperature resulting from formula (V), but not above 170° C.

(96) Compounds of the general formula (III) that are used in the process according to the invention are all known polyamines having primary amino groups that conform to the general formula (III). Examples include the following compounds: ethylenediamine, 1,2-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 2,5-diamino-2,5-dimethylhexane, 1,5-diamino-2-methylpentane (Dytek®A, DuPont), 1,6-diaminohexane, 2,2,4- and/or 2,4,4-trimethyl-1,6-diaminohexane, 1,11-diaminoundecane, 1,12-diaminododecane or triaminononane, etheramines such as 4,9-dioxadodecane-1,12-diamine, 4,7,10-trioxatridecane-1,13-diamine, or higher-molecular-weight polyether polyamines having aliphatically attached primary amino groups, for example those marketed under the Jeffamine® name by Huntsman. Also employable are aliphatic polycyclic polyamines such as tricyclodecanebismethylamine (TCD diamine) or bis(aminomethyl)norbornanes, amino-functional siloxanes, for example diaminopropylsiloxane G10 DAS (from Momentive), oleoalkyl-based amines, for example Fentamine from Solvay, dimeric fatty acid diamines such as Priamine from Croda.

(97) In the process according to the invention, preference is given to the use of polyamines of the general formula (III), in which m=2 and X is a cyclic hydrocarbon radical having at least one cyclic carbon ring. Examples of diamines that are usable with particular preference are 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane (IPDA), 2,4- and/or 2,6-hexahydrotolylenediamine (H6-TDA), isopropyl-2,4-diaminocyclohexane, and/or isopropyl-2,6-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 2,4′-, and/or 4,4′-diaminodicyclohexylmethane, 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane (Laromin® C 260, BASF AG), the isomeric diaminodicyclohexylmethanes substituted in the ring with a methyl group (═C-monomethyl-diaminodicyclohexylmethanes), 3(4)-aminomethyl-1-methylcyclohexylamine (AMCA), and also araliphatic diamines such as 1,3-bis(aminomethyl)benzene or m-xylylenediamine. In the process according to the invention, preference is also given to the use of polyamines of the general formula (III) selected from the following group: polyether polyamines having aliphatically attached primary amino groups, 1,2-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,5-diamino-2-methylpentane, 2,5-diamino-2,5-dimethylhexane, 2,2,4- and/or 2,4,4-trimethyl-1,6-diaminohexane, 1,11-diaminoundecane, 1,12-diaminododecane, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane, 2,4- and/or 2,6-hexahydrotolylenediamine, 2,4′- and/or 4,4′-diaminodicyclohexylmethane or 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane. Particular preference is given to 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, 2,4′- and/or 4,4′-diaminodicyclohexylmethane, 1,5-diamino-2-methylpentane, and very particular preference to the use of 2,4′- and/or 4,4′-diaminodicyclohexylmethane.

(98) Particular preference is given to the polyaspartic ester compositions according to the invention in which X is organic radicals obtained by removing the primary amino groups from one of the polyamines of the general formula (III) selected from the following group: polyether polyamines having aliphatically attached primary amino groups, 1,2-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,5-diamino-2-methylpentane, 2,5-diamino-2,5-dimethylhexane, 2,2,4- and/or 2,4,4-trimethyl-1,6-diaminohexane, 1,11-diaminoundecane, 1,12-diaminododecane, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane, 2,4- and/or 2,6-hexahydrotolylenediamine, 2,4′- and/or 4,4′-diaminodicyclohexylmethane or 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane.

(99) Most preferred are the polyaspartic ester compositions according to the invention in which X is organic radicals obtained by removing the primary amino groups from one of the polyamines of the general formula (III) selected from the following group: 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, 2,4′- and/or 4,4′-diaminodicyclohexylmethane, 1,5-diamino-2-methylpentane.

(100) Preferred compounds of the general formula (IV) that are used in the process according to the invention are maleic or fumaric esters of the general formula (IV) in which R1 and R2 are identical or different organic radicals each having 1 to 18 carbon atoms. Preferably, R1 and R2 are independently linear or branched alkyl radicals having 1 to 8 carbon atoms. Examples of compounds of the general formula (IV) are the following compounds: dimethyl maleate, diethyl maleate, di-n-propyl or diisopropyl maleate, di-n-butyl maleate, di-2-ethylhexyl maleate or the corresponding fumaric esters. Particular preference is given to diethyl maleate.

(101) The polyaspartic ester compositions according to the invention are valuable reaction partners for polyisocyanates in low-solvent or solvent-free two-component polyurethane systems.

(102) The invention thus also provides for the use of the polyaspartic ester compositions according to the invention as a reactive component in two-component polyurethane systems or in the production of prepolymers. The two-component (2K) polyurethane systems comprising the polyaspartic ester compositions according to the invention may then be used as coating compositions in the production of coatings.

(103) In addition to the components essential to the invention, the coating compositions essential to the invention may also employ auxiliaries customary in coating technology such as inorganic or organic pigments, other organic light stabilizers, free-radical scavengers, coatings additives such as dispersants, leveling agents, thickeners, defoaming agents and other auxiliaries, bonding agents, fungicides, bactericides, stabilizers or inhibitors and catalysts.

(104) The coating compositions according to the invention are preferably used in the fields of OEM finishing of automobiles, refinishing of automobiles, coatings for large vehicles, coatings for plastics, general industrial coatings, coatings for floors and/or for wood/furniture.

(105) The invention accordingly also further provides coated substrates obtainable using the polyaspartic ester compositions according to the invention.

EXPERIMENTAL

(106) Raw Materials:

(107) Vestamin PACM: a mixture of 2,4- and 4,4′-diaminodicyclohexylmethane, manufacturer: Evonik

(108) Desmodur N 3600: a low-viscosity HDI trimer containing approx. 23% NCO and ≤0.25% free HDI, manufacturer: Covestro

(109) Desmodur N 3900: a low-viscosity HDI trimer containing approx. 23.5% NCO and ≤0.25% free HDI, manufacturer: Covestro

(110) Byk 331: polyether-modified polydimethylsiloxane surface additive, manufacturer: Byk

(111) Tinuvin 292: a mixture of bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate and methyl 1,2,2,6,6-pentamethyl-4-piperidylsebacate, a light stabilizer from BASF

(112) Tinuvin 384-2: benzenepropanoic acid, 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy, C.sub.7-C.sub.9 branched and linear alkyl esters, a light stabilizer from BASF

(113) Methods:

(114) Diethyl fumarate contents were quantitatively determined using a GC method with internal standard. An Agilent 6890 gas chromatograph with a standard GC capillary (100% polysiloxane phase) and FID detector were used. The injector temperature (split outlet) was 180° C.; helium was used as the carrier gas. The quantitation limit of this method was 300 ppm.

(115) GC-MS analyses were carried out using an Agilent 6890 gas chromatograph and Agilent 5973 mass spectrum detector with standard ionization (electron impact) at 70 eV, a standard GC capillary (100% polysiloxane phase) and split injection at an injector temperature of 250° C. Evaluation of the gas chromatograms was in area-%.

(116) All viscosity measurements were carried out using a Physica MCR 51 rheometer from Anton Paar Germany GmbH (DE) in accordance with DIN EN ISO 3219:1994-10.

(117) NCO contents were determined titrimetrically in accordance with DIN EN ISO 11909:2007-05.

(118) Hazen color index values were determined on a Lico 400 colorimeter from Hach Lange GmbH,

(119) Düsseldorf in accordance with DIN EN ISO 6271:2016-05

(120) Amine values were determined titrimetrically in accordance with EN ISO 9702:1998 (perchloric acid method) with the exception that the results were expressed as the amine value. The amine value in mg KOH/g was calculated according to the following equation:

(121) $\mathrm{Amine}\mathrm{value}=\frac{\left(a-b\right)\times 5.61}{W}$
a=volume of perchloric acid consumed in the main test, in milliliters, c=0.1 mol/l;
b=volume of perchloric acid consumed in the blank test, in milliliters, c=0.1 mol/l;
W=weight of sample, in grams

(122) Flow times were determined in accordance with DIN EN ISO 2431:2012-03, with the exception that a DIN 4 flow cup was used. The pot life was defined as the time corresponding to twice the flow time.

(123) Drying determinations were carried out in accordance with DIN EN ISO 9117-5:2012-11.

(124) For the determination of reactivity, the following gel-time measurement method was developed: The feedstocks (total amount 10 g) were weighed into a beaker and mixed for 15 seconds at 3000 rpm in a Speedmixer. Then, using a bent paperclip or a disposable pipette, the time taken for the mixture to be drawn into threads or to become solid was determined with a stopwatch.

Example 1 (Comparative Example)

(125) Polyaspartic ester commercially available from Covestro under the name Desmophen NH 1420.

(126) Material data:

(127) TABLE-US-00001 Monoamine of the formula (II) (GC-MS): 4.0% Diethyl fumarate (GC) 2.9% by weight Viscosity 1220 mPas Color index 27 APHA Amine value 201 mg KOH/g

Example 2 (Comparative Example)

(128) 341.8 g of Vestamin PACM was initially charged at 23° C. under dry nitrogen, with stirring. To this was added dropwise 839.4 g of diethyl maleate, ensuring that the temperature did not rise above 60° C. At the end of the addition, the temperature was adjusted to 45° C. and the mixture was stirred for one hour at 45° C. The mixture was then stored at 23° C. for 8 weeks. The content of diethyl fumarate after storage was 0.04% by weight. A light-colored product was obtained that had the following material data:

(129) TABLE-US-00002 Monoamine of the formula (II) (GC-MS): 65.8% Diethyl fumarate (GC) 0.04% by weight Viscosity 690 mPas Color index 16 APHA Amine value 293 mg KOH/g

Example 3 (Comparative Example)

(130) 341.8 g of Vestamin PACM was initially charged at 23° C. under dry nitrogen, with stirring. To this was added dropwise 1678.8 g of diethyl maleate, ensuring that the temperature did not rise above 60° C. At the end of the addition, the temperature was adjusted to 45° C. and the mixture was stirred for one hour at 45° C. The mixture was then stored at 23° C. for 24 hours. The content of diethyl fumarate after storage was 11.5% by weight. Diethyl fumarate was then distilled off at 120° C. and 0.2 mbar. A light-colored product was obtained that had the following material data:

(131) TABLE-US-00003 Monoamine of the formula (II) (GC-MS): 25.4% Diethyl fumarate (GC) 0.05% by weight Viscosity 1330 mPas Color index 8 APHA Amine value 224 mg KOH/g

Example 4

(132) 341.8 g of P Vestamin PACM was initially charged at 23° C. under dry nitrogen, with stirring. To this was added dropwise 1678.8 g of diethyl maleate, ensuring that the temperature did not rise above 60° C. At the end of the addition, the temperature was adjusted to 45° C. and the mixture was stirred for 2 hours at 45° C. The mixture was then stored at 23° C. for 7 weeks. The content of diethyl fumarate after storage was 2.7% by weight. Diethyl fumarate was then distilled off at 120° C. and 0.2 mbar. A light-colored product was obtained that had the following material data:

(133) TABLE-US-00004 Monoamine of the formula (II) (GC-MS): 5.3% Diethyl fumarate (GC) 0.08% by weight Viscosity 1810 mPas Color index 19 APHA Amine value 203 mg KOH/g

Example 5

(134) 341.8 g of Vestamin PACM was initially charged at 23° C. under dry nitrogen, with stirring. To this was added dropwise 1678.8 g of diethyl maleate, ensuring that the temperature did not rise above 60° C. At the end of the addition, the temperature was adjusted to 45° C. and the mixture was stirred for two hours at 45° C. The mixture was then stored at 23° C. for 30 hours. The content of after storage was 8.62% by weight. Diethyl fumarate was then distilled off at 120° C. and 0.2 mbar. A light-colored product was obtained that had the following material data:

(135) TABLE-US-00005 Monoamine of the formula (II) (GC-MS): 13.2% Diethyl fumarate (GC) <0.03% by weight Viscosity 1650 mPas Color index 5 APHA Amine value 213 mg KOH/g

Example 6

(136) 341.8 g of Vestamin PACM was initially charged at 23° C. under dry nitrogen, with stirring. To this was added dropwise 1678.8 g of diethyl maleate, ensuring that the temperature did not rise above 60° C. At the end of the addition, the temperature was adjusted to 45° C. and the mixture was stirred for one hour at 45° C. The mixture was then stored at 23° C. for 24 hours. The content of diethyl fumarate after storage was 8.85% by weight. Diethyl fumarate was then distilled off at 120° C. and 0.2 mbar. A light-colored product was obtained that had the following material data:

(137) TABLE-US-00006 Monoamine of the formula (II) (GC-MS): 14.1% Diethyl fumarate (GC) 0.08% by weight Viscosity 1630 mPas Color index 5 APHA Amine value 214 mg KOH/g

(138) Before performance testing, the reactivity of selected polyaspartic esters was determined by the gel-time measurement method described above.

(139) TABLE-US-00007 TABLE 1 Determination of reactivity by the gel-time measurement method Desmodur Desmodur Desmodur Desmodur Desmodur Feedstock N 3600 N 3600 N 3600 N 3600 N 3600 Sample 4.18 4.88 4.22 4.18 4.18 weight Feedstock Example 1 Example 2 Example 3 Example 5 Example 6 Sample 5.82 5.11 5.78 5.82 5.82 weight Time until: sample can 37 min n.d.* 5 min 49 min 52 min be drawn into threads the sample 65 min n.d.* 7 min 88 min 92 min is solid *Gelation of sample in Speedmixer

(140) It can be seen from table 1 that the inventive composition comprising polyaspartic esters from examples 5 and 6, despite having a higher content of polyaspartic esters having primary amino groups compared to the commercially available product, does not show a shortened gel time and is therefore suitable for coatings.

(141) Testing in Coatings

(142) Inventive polyaspartic ester compositions from examples 1 and 5 were tested in coating formulations.

(143) Preparation of a Coating Base

(144) To the amount of component A shown in table 2 were added the additives and the amount of butyl acetate shown in the table, and the mixture was stirred thoroughly.

(145) Preparation of the Hardener Solution

(146) To the amount of component B shown in table 2 was added the amount of butyl acetate shown in the table, and the mixture was stirred thoroughly.

(147) Mixing of the coating base with the hardener and application:

(148) The coating base described above and the hardener were combined and mixed thoroughly. The mixtures were then each applied with an air gun to coil-coating sheet precoated with black basecoat, flashed off for 10 min at room temperature, and then dried at room temperature and at 60° C. Brilliant, high-gloss coatings with a layer thickness of 50 μm were obtained.

(149) An overview of the coating properties determined for the coatings is shown in table 3.

(150) TABLE-US-00008 TABLE 2 Composition of the coating bases Example 7 Example 8 Example 9 Temperature: 24° C. (inventive) (inventive) (comparative) Air humidity: 48% Component A Example 5 43.77 Example 4 45.25 Example 1 47.24 Byk 331 (10% in BA) 0.08 0.08 0.08 Tinuvin 292 (50% in BA) 0.16 0.17 0.16 Tinuvin 384-2 (50% in BA) 0.33 0.33 0.33 Butyl acetate 21.34 20.00 16.19 Component B Desmodur N 3900 (100%) 29.75 29.42 30.65 Butyl acetate 1.57 1.75 2.35

(151) TABLE-US-00009 TABLE 3 Coating properties of coatings Temperature: 24° C. Example 7 Example 8 Example 9 Relative humidity: 48% Solids content in %   73.4   74.9   81.1 at spray viscosity (calc.) Flow time DIN 4 mm 0 h 17 16 17 (sec)  5′ 18 17 18 10′ 19 18 20 15′ 21 19 24 20′ 23 20 27 25′ 27 22 31 30′ 32 25 40 Drying (min) T 1 13 12 15 RT T 3 27 25 30 T 4 40 40 45 Layer thickness (μm) about 50 about 50 about 50 Drying (min) T 1 immediately immediately immediately 30′-60° C. T 3 15 15 20 T 4 27 25 30 Layer thickness (μm) about 50 about 50 about 50

(152) Comparison of the coating properties shown in table 3 for the comparison coating (example 9) with those of the inventive coatings (examples 7 and 8) demonstrates that the inventive coatings dry more rapidly while having an unchanged pot life.