EP3927757A1

EP3927757A1 - Novel two-component outer coating containing polyaspartic acid esters

Info

Publication number: EP3927757A1
Application number: EP20705080.8A
Authority: EP
Inventors: Dorota Greszta-Franz; Jan Weikard; Matthias Wintermantel; Robert Reyer; Thomas SCHÜTTLER
Original assignee: Covestro Intellectual Property GmbH and Co KG
Current assignee: Covestro Deutschland AG
Priority date: 2019-02-22
Filing date: 2020-02-20
Publication date: 2021-12-29
Also published as: JP2022521250A; KR20210131331A; CN113412293B; US20220145121A1; WO2020169701A1; CN113412293A; EP3699218A1

Abstract

The invention relates to two-component outer coating systems containing polyaspartic acid ester with only small amounts of fumaric acid diakly ester, to a method for the production thereof and to the use thereof for producing coatings, in particular for protecting against corrosion, and to the use in the field of general industrial coating or in the field of ACE (Agriculture, Construction and Earth moving equipment) and to substrates coated therewith.

Description

New two-component top coating systems containing polyaspartic acid esters

The present invention relates to two-component top coating systems containing polyaspartic acid esters with only small amounts of fumaric acid dialkyl ester, a process for their production and their use for producing coatings, in particular for corrosion protection, and for use in the field of ACE (Agriculture, Construction and Earth moving equipment) and substrates coated therewith.

Two-component (2K) coating compositions which contain a polyisocyanate component as a binder in combination with a reactive component which is reactive toward isocyanate groups, in particular a polyhydroxyl component, have been known for a long time. They are suitable for the production of high-quality coatings that can be made hard, elastic, abrasion and solvent-resistant and, above all, weather-resistant.

Within this two-component polyurethane coating technology, certain secondary polyamines containing ester groups have recently become established, the so-called polyaspartic acid esters or polyaspartates, which, in combination with lacquer polyisocyanates, are particularly suitable as binders in low-solvent or solvent-free (high solids) coating materials and a rapid curing of the coatings at low temperatures.

The use of such polyaspartic acid esters in top coatings enables, in addition to the aforementioned rapid curing of these coatings, a reduced layer structure, which is very attractive for use in the area of top coatings. In the area of corrosion protection and ACE (Agriculture, Construction and Earth moving equipment), however, the conventional polyaspartate-based top coatings have not yet been able to establish themselves because of their loss of gloss. For a long time there has therefore been a desire in the market for pigmented top coatings based on polyaspartate which have improved gloss stability.

The use of polyaspartic acid esters alone or in a mixture with other components which are reactive towards isocyanate groups in 2K coating agents is described, for example, in EP0403921, EP0639628, EP0667362, EP0689881, US5214086, EP0699696, EP0596360, EP0893458, DE047018151, EP0893458, DE019701501, DE0470181535

US5243012 described.

The production of amino-functional aspartic acid esters is known per se. The synthesis takes place via an addition of primary polyamines to an activated carbon double bond of vinylogous carbonyl compounds, as contained, for example, in maleic or fumaric acid esters, which is sufficiently described in the literature (Hauben Weyl, Meth. D. Org. Chemie Vol. 11/1 , 272 (1957), Usp. Khim. 1969, 38, 1933). This reaction can lead to the formation of a polyaspartic acid ester with primary amino groups as a by-product if only one amino group of the polyamine has reacted with the double bond of the vinylogous carbonyl compounds. In the commercially available polyaspartic acid esters, maleic acid ester is used as the vinylogous carbonyl compound. During the production of a polyaspartic acid ester based on maleic acid ester, a retro-Michael addition can take place as a further undesired side reaction in which dialkyl fumarate is formed by elimination of the polyamine as a secondary component. A typical production process for a polyaspartic acid ester therefore requires a storage time of 4-6 weeks after most of the starting materials have reacted with one another. During this time, the so-called ripening of the product takes place, which manifests itself through stabilization of the viscosity. Because the conversion continues to rise within this time, the content of dialkyl fumarate also falls. This storage over several weeks leads to considerable logistics costs within production. Although the product is only delivered to the customer after storage, it still contains substantial amounts of dialkyl fumarate, which can cause severe sensitization. The polyaspartic acid esters produced in this way usually still contain residues of 3 to 20 percent by weight of fumaric acid ester after ripening.

The object of the present invention was to provide a coating composition based on polyaspartic acid esters for producing gloss-stable pigmented top coatings.

It was surprisingly found that this object can be achieved by coating compositions based on polyaspartic acid esters with a greatly reduced content of dialkyl fumarate. The content of fumaric acid dialkyl ester in the polyaspartic acid ester component is, according to the invention, 0.01 to 1.2% by weight, preferably 0.01 to 1% by weight, particularly preferably 0.01 to 0.1% by weight, and can be determined by a special Distillation process can be reduced to these values.

A theoretical possibility of working up polyaspartic acid esters by distillation is mentioned, for example, in EP0403921. This disclosure does not give any examples or method of distillation. In addition, there is no indication in EP0403921 that polyaspartic acid esters with a maximum fumaric acid dialkyl ester content of 1.2% by weight should be used in the production of pigmented top coatings, and even less that this leads to an improvement in the gloss stability of these coatings. In comparative example III, DE102006002153 likewise describes a polyaspartic acid ester which is freed from dialkyl fumarate by distillation. Here, too, the use of polyaspartic acid esters with a reduced content of fumaric acid dialkyl ester according to the invention for the production of pigmented top coatings or the effect that can be achieved thereby is neither mentioned nor suggested.

WO2018 / 074884 and WO2018 / 074885, which had not yet been published at the time the present invention was applied for a patent, likewise describe the distillation of polyaspartic acid esters, WO2018074884 also describes their use in coating compositions. Neither of the two documents describes pigmented top coatings based on these purified esters.

The present invention relates to two-component coating compositions (2K coating agents) containing a) at least one component A containing polyaspartic acid ester,

b) at least one polyisocyanate component B

c) if appropriate, one or more components C which are different from A and which are reactive towards isocyanate groups,

d) at least one inorganic and / or organic pigment, preferably in a proportion of at least 3% by weight (> 3% by weight), based on the total weight of the two-component composition (component Dl), and

if necessary further auxiliaries and additives (component D2).

In the context of the present invention, components A containing polyaspartic acid esters are compositions containing one or more polyaspartic acid esters of the general formula (I)

(I),

in which

X is a mivalent organic radical, optionally containing one or more heteroatoms, such as that obtained by removing the primary amino groups from a corresponding polyamine having (cyclo) aliphatically or araliphatically bound primary amino groups of the molecular weight range 60 to 6000 g / mol can be obtained, and which can contain further functional groups which are reactive towards isocyanate groups and / or which are inert at temperatures up to 100 ° C,

RI and R2 for identical or different organic radicals, each with 1 to 18

Carbon atoms, m stands for an integer> 1,

and

optionally one or more polyaspartic acid esters with a primary amino group of the general formula (II)

in which

n stands for m-1,

X, radicals RI and R2 have the meanings given above, characterized in that, in component A, fumaric acid dialkyl ester is based in an amount of 0.01 to 1.2% by weight (> 0.01 to <1.2% by weight) based on the total weight of component A.

Components A containing polyaspartic acid esters are preferred, compositions containing one or more polyaspartic acid esters of the general formulas (I) and optionally (II) in which RI and R2 are identical or different alkyl radicals with 1 to 18 carbon atoms each, preferably identical or different alkyl radicals with 1 to 8 carbon atoms and very particularly preferably each alkyl radicals such as methyl, ethyl, propyl, iso-propyl, butyl or iso-butyl radicals. Most preferred is ethyl.

Polyaspartic acid ester-containing components A are compositions containing one or more polyaspartic acid esters of the general formulas (I) and optionally (II), in which X stands for organic radicals which are formed by removing the primary amino groups from a corresponding (cyclo) aliphatically or araliphatically bonded one polyamine containing primary amino groups are obtained, selected from the following group: all known polyamines with primary amino groups which correspond to the general formula (III). Exemplary the following compounds may be mentioned: ethylenediamine, 1,2-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 2,5-diamino-2,5-dimethylhexane, 1,5-diamino-2-methylpentane (Dytek® A, Fa Invista), 1,6-diaminohexane, 2,2,4- and / or 2,4,4-trimethyl-1,6-diaminohexane, 1,11-diaminoundecane, 1,12-diaminododecane or triaminononane, ether amines , such as 4,9-dioxadodecane-l, 12-diamine, 4,7,10-trioxatridecane-l, 13-diamine, or higher molecular weight polyether polyamines with aliphatically bonded, primary amino groups, such as those from the company under the name Jeffamin® Huntsman to be evicted. It is also possible to use aliphatic polycyclic polyamines, such as tricyclodecane dismethylamine (TCD diamine) or bis (aminomethyl) norbornane, amino-functional siloxanes, for example diaminopropylsiloxane G10 DAS (from Momentive), fatty alkyl-based amines such as, for example, fentamines from Solvay, dimer fatty acid diamines such as, for example, Priamine from Croda.

Components A containing polyaspartic acid esters are preferred, compositions containing one or more polyaspartic acid esters of the general formula (I) and optionally (II) in which X represents organic radicals obtained by removing the primary amino groups from one of the polyamines of the general formula (III) , where m = 2 and X stands for a cyclic hydrocarbon radical with at least one cyclic carbon ring. Examples of diamines that can be used with particular preference are l-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'-diamino-dicyclohexylmethane, 3,3'-dimethyl- 4,4'-diamino-dicyclohexylmethane (Faromin® C 260, from BASF AG), the isomeric diaminodicyclohexylmethane (= C-monomethyl-diaminodicyclohexy imethane), 3 (4) -aminomethyl-1-methylcyclohexylamine ( AMCA) and araliphatic diamines, such as 1,3-bis (aminomethyl) benzene or m-xylylenediamine.

Also preferred are polyaspartic acid ester-containing components A compositions containing one or more polyaspartic acid esters of the general formula (I) and optionally (II) in which X stands for organic radicals obtained by removing the primary amino groups from one of the polyamines of the general formula (III) is selected from the group: polyether polyamines with aliphatically bound 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-diaminounodecane, 1,2-diaminododecane, 1-amino-3, 3, 5-trimethyl-5 -aminomethylcyclohexane, 2,4- and / or 2,6-hexahydrotoluylenediamine, 1,5-diaminopentane, 2,4'- and / or 4,4'-diamino-dicyclohexylmethane or 3,3'-dimethyl-4,4 '-diamino-dicyclohexylmethane. 3,3'-Dimethyl-4,4'-diamino-dicyclohexyl methane, 1,5-diaminopentane, 2,4'- and / or 4,4'- are particularly preferred Diaminodicyclohexylmethane, 1,5-diamino-2-methylpentane and the use of 2,4'- and / or 4,4'-diaminodicyclohexylmethane is very particularly preferred.

Particularly preferred are polyaspartic acid ester-containing components A compositions containing one or more polyaspartic acid esters of the general formulas (I) and optionally (II) in which X stands for organic radicals obtained by removing the primary amino groups from one of the polyamines of the general formula (III) is obtained, selected from the group: polyether polyamines with aliphatically bonded 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-l, 6-diaminohexane, 1,11-diaminounodecane, 1,12-diaminododecane, l-amino-3, 3,5-trimethyl-5-aminomethylcyclohexane, 2,4- and / or 2,6-hexahydrotoluylenediamine, 2,4'- and / or 4,4'-diamino-dicyclohexylmethane or 3,3'-dimethyl-4,4 'diamino-dicyclohexylmethane.

Components A containing polyaspartic acid esters are very particularly preferred. Compositions containing one or more polyaspartic acid esters of the general formulas (I) and optionally (II) in which X stands for organic radicals which are obtained by removing the primary amino groups from one of the polyamines of the general formula (III ) is obtained, selected from the group: 3,3'-dimethyl-4,4'diaminodicyclohexylmethane, 2,4'- and / or 4,4'-diaminodicyclohexylmethane, 1,5-diamino-2-methylpentane.

Index m stands for an integer> 1 and preferably for 2.

If the polyaspartic acid ester-containing component A contains one or more polyaspartic acid esters of the general formula (II), this / these is / are in a proportion of> 0%, preferably at least 0.1% (> 0.1%), particularly preferably at least 1% (> 1%), very particularly preferably at least 4% (> 4%), and preferably of a maximum of 20% (<20%), particularly preferably a maximum of 15% (<15%) of the GC surface (measured as area % in the gas chromatogram), the sum of the GC surfaces of the compounds of the two general formulas (I) and (II) being 100%. The specified upper and lower limits can be combined as required. All possible combinations are considered disclosed.

Components A containing polyaspartic acid esters are preferred, compositions containing one or more polyaspartic acid esters of the general formulas (I) and, if appropriate, formula (II), in a proportion of 0.01 to 1.2% by weight (> 0.01 to <1, 2% by weight), preferably 0.01 to 1% by weight (> 0.01 to <1% by weight), particularly preferably 0.01 to 0.1% by weight (> 0.01 to <0.1% by weight), based on the total weight of component A, of dialkyl fumarate. Particularly preferred are polyaspartic acid esters dialtige components A compositions containing one or more polyaspartic acid esters of the general formula (I),

in which

X stands for an m-valent organic radical, optionally containing one or more fletero atoms, as obtained by removing primary amino groups from polyether polyamines with aliphatically bonded 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-diaminounodecane, 1,12-diaminododecane, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane, 2,4- and / or 2,6-flexahydrotoluylenediamine, 2,4'- and / or 4, 4'-diamino-dicyclohexyl methane or 3,3'-dimethyl-4,4'-diamino-dicyclohexyl methane is obtained,

RI and R2 stand for identical or different alkyl radicals each with 1 to 8 carbon atoms,

m stands for an integer> 1,

and

one or more polyaspartic acid esters with a primary amino group of the general formula (P),

in which

n stands for m-1,

X, radicals RI and R2 have the abovementioned meanings, characterized in that the proportion of compounds of the general formula (II)> 0%, preferably at least 0.1% (> 0.1%), particularly preferably at least 1% ( > 1%), very particularly preferably at least 4% (> 4%) of the GC surface (measured as% area in the gas chromatogram), the sum of the GC surfaces of the compounds of the two general formulas (I) and (II) 100%, and in component A dialkyl fumarate is present in an amount of 0.01 to 1.2% by weight (> 0.01 to <1.2% by weight), based on the total weight of component A.

An alternative, particularly preferred embodiment corresponds to that described above, but the component A containing polyaspartic acid ester does not contain any polyaspartic acid esters with a primary amino group of the general formula (II). Components A containing polyaspartic acid esters are very particularly preferred. Compositions comprising one or more polyaspartic acid esters of the general formula (I) in which

X stands for an m-valent organic radical, as it is obtained by removing primary amino groups from 3,3‘-dimethyl

4,4'diaminodicyclohexylmethane, 2,4‘- and / or 4,4‘-

Diaminodicyclohexylmethane, l, 5-diamino-2-methylpentane can be obtained,

RI and R2 for identical or different alkyl radicals selected from the group

Methyl, ethyl, propyl, iso-propyl, butyl or iso-butyl radicals, m stands for 2,

and

in which

n stands for m-1,

X, radicals RI and R2 have the abovementioned meanings, characterized in that the proportion of compounds of the general formula (II)> 0%, preferably at least 0.1% (> 0.1%), particularly preferably at least 1% ( > 1%), very particularly preferably at least 4% (> 4%) of the GC surface (measured as% area in the gas chromatogram), the sum of the GC surfaces of the compounds of the two general formulas (I) and (II) Is 100% and in component A fumaric acid dialkyl ester in an amount of 0.01 to 1 wt .-% (> 0.01 to <1 wt .-%), based on the total weight of component A, are present.

An alternative, very particularly preferred embodiment corresponds to that described above, but the component A containing no polyaspartic acid esters with a primary amino group of the general formula (II).

Most preferred are polyaspartic acid ester-containing components A compositions containing one or more polyaspartic acid esters of the general formula (I),

in which

X stands for an m-valent organic radical, as obtained by removing primary amino groups from 3,3'-dimethyl-4,4'diamino- dicyclohexylmethane, 2,4'- and / or 4,4'-diaminodicyclohexylmethane can be obtained,

RI and R2 stand for ethyl residues,

m stands for 2,

and

one or more polyaspartic acid esters with a primary amino group of the general formula

(P),

in which

n stands for m-1,

X, radicals RI and R2 have the abovementioned meanings, characterized in that the proportion of compounds of the general formula (II)> 0%, preferably at least 0.1% (> 0.1%), particularly preferably at least 1% ( > 1%), very particularly preferably at least 4% (> 4%) of the GC surface (measured as area% in the gas chromatogram), the sum of the GC surfaces of the compounds of the two general formulas (I) and (II) Is 100% and in component A fumaric acid dialkyl ester in an amount of 0.01 to 0.1 wt .-% (> 0.01 to <0.1 wt .-%), based on the total weight of component A, are present.

An alternative, most preferred embodiment corresponds to that described above, except that the polyaspartic acid ester-containing component A does not contain any polyaspartic acid esters having a primary amino group of the general formula (II).

Components A containing polyaspartic acid esters are preferred. Compositions containing one or more polyaspartic acid esters of the general formula (I) and, if appropriate, formula (II) which have a platinum-cobalt color number <100, particularly preferably <50. The platinum-cobalt color number is measured in accordance with DIN EN ISO 6271: 2016-05.

Components A containing polyaspartic acid esters and containing one or more polyaspartic acid esters of the general formula (I) and formula (II) can be produced by the following process:

Implementation of polyamines of the general formula (III),

(III), where X

represents an m-valent organic radical, optionally containing one or more heteroatoms, as can be obtained by removing the primary amino groups from a polyamine having (cyclo) aliphatically or araliphatically bonded primary amino groups and having a molecular weight range of 60 to 6000 g / mol, and which can contain further functional groups which are reactive towards isocyanate groups and / or which are inert at temperatures up to 100 ° C., m is an integer> 1, preferably 2, with compounds of the general formula (IV)

R1 OOC-CH = CH-COOR2

(IV),

where RI and R2

for identical or different organic radicals, preferably for identical or different alkyl radicals with 1 to 18 carbon atoms each, particularly preferably for identical or different alkyl radicals with 1 to 8 carbon atoms each, very particularly preferably for each alkyl radicals such as methyl, ethyl, propyl , iso-propyl, butyl or iso-butyl radicals and most preferably represent ethyl, and removal of the unreacted portion of the compound of the general formula (IV) by distillation.

The above-described process for preparing the polyaspartic acid ester-containing components A, comprising one or more polyaspartic acid esters of the general formula (I) and formula (II), is preferably carried out in two steps. In the first step, the compounds of general formula (III) and (IV) at temperatures between 0 ° C and 100 ° C, preferably 20 ° to 80 ° C and particularly preferably 20 ° to 60 ° C, in a ratio of the equivalents of primary amino groups of the compounds of the general formula (III) to the C = C double bond equivalents of the compounds of the general formula (IV) from 1: 1.2 to 1.2: 1, but preferably 1: 1.05 to 1.05: 1 up to a residual content of compounds of General formula (IV) from 2 to 15 percent by weight, preferably from 3 to 10 percent by weight.

In the second step, the unreacted portion of the compounds of the general formula (IV) is removed by distillation. Polyaspartic acid ester-containing components A which only contain polyaspartic acid esters of the general formula (I), but not of the formula (II), can be prepared analogously, but working with an excess of compounds of the general formula IV, ie in a ratio of Equivalents of the primary amino groups of the compounds of the general formula (III) to the C =C double bond equivalents of the compounds of the general formula (IV) of 1:10, preferably 1: 5, particularly preferably 1: 2.

Suitable conditions during the distillation are a pressure range between 0.01 and 2 mbar and a temperature of the bottom outlet at the outlet from the distillation apparatus is <170 ° C and> the temperature that results from the following formula (V):

T (sump drain) = 27 x ln (p) + 150 (V) where T (sump drain) is the temperature of the sump drain in ° C and

p for the pressure in the distillation apparatus in mbar

stand.

Maintaining this pressure range ensures that, on the one hand, moderate temperatures in the bottom outlet are sufficient to deplete the dialkyl fumarate to the desired extent and, on the other hand, the process can still be used on an industrial scale. If the pressure is lower, the gas density becomes too low and the equipment required is therefore so large that the process is disadvantageous from an economic point of view.

The temperature of the bottom outflow is preferably <170 ° C., but at least 20 K above the temperature resulting from the formula (V), particularly preferably it is between 20 K and 40 K above the temperature resulting from the formula ( V) does not give above 170 ° C.

Compounds of the general formula (III) which are used in the process described above are all known polyamines with primary amino groups which correspond to the general formula (III). The following compounds may be mentioned as examples: ethylenediamine, 1,2-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 2,5-diamino-2,5-dimethylhexane, 1,5-diamino-2-methylpentane (Dytek ®A, Invista), 1,6-diaminohexane, 2,2,4- and / or 2,4,4-trimethyl-l, 6-diaminohexane, 1.1 l-diaminoundecane, l, 12-diaminododecane or triaminononane , Etheramines, such as, for example, 4,9-dioxadodecane-l, 12-diamine, 4,7,10-trioxatridecane-l, 13-diamine, or higher molecular weight polyether polyamines with aliphatically bonded primary amino groups, such as those for example under the name Jeffamin® from by Huntsman. Aliphatic polycyclic polyamines, such as tricyclodecane dismethylamine, can also be used (TCD-diamine) or bis (aminomethyl) norbornane, amino-functional siloxanes, for example diaminopropylsiloxane G10 DAS (from Momentive), fatty alkyl-based amines, such as, for example, fentamines from Solvay, dimer fatty acid diamines such as, for example, Priamine from Croda.

In the process described above, preference is given to using 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 which can be used with particular preference are l-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 '-diamino-dicyclohexylmethane (Laromin® C 260, BASF AG), the isomeric diaminodicyclohexylmethane (= C-monomethyl-diaminodicyclohexylmethane) having a methyl group as a core substituent, 3 (4) -

Aminomethyl-1-methylcyclohexylamine (AMCA) and araliphatic diamines, e.g. 1,3-bis (aminomethyl) benzene or m-xylylenediamine.

Polyamines of the general formula (III) are also preferably used in the process according to the invention, selected from the group: polyether polyamines with aliphatically bound 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-diaminounodecane, 1,12-diaminododecane, 1-amino

3.3.5-trimethyl-5-aminomethylcyclohexane, 2,4- and / or 2,6-hexahydrotoluenediamine, 2,4'- and / or 4,4'-diamino-dicyclohexylmethane or 3,3'-dimethyl-4,4 '-diamino-dicyclohexylmethane. 3,3'-dimethyl-4,4'-diamino-dicyclohexylmethane, 2,4'- and / or 4,4'-diaminodicyclohexylmethane, 1,5-diamino-2-methylpentane are particularly preferred and their use is very particularly preferred of 2,4- and / or 4,4'-diaminodicyclohexyl methane.

Polyamines of the general formula (III) are particularly preferably used in the process according to the invention, selected from the group: polyether polyamines with aliphatically bound 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

3.3.5-trimethyl-5-aminomethylcyclohexane, 2,4- and / or 2,6-hexahydrotoluenediamine, 2,4'- and / or 4,4'-diamino-dicyclohexylmethane or 3,3'-dimethyl-4,4 'diamino-dicyclohexylmethane. Polyamines of the general formula (III) are very particularly preferably used in the process according to the invention, selected from the group 3,3'-dimethyl-4,4'diaminodicyclohexylmethane, 2,4'- and / or 4,4'-diaminodicyclohexylmethane, l, 5-diamino-2-methylpentane.

Preferred compounds of the general formula (IV) which are used in the process described above are maleic or fumaric acid esters of the general formula (IV) in which RI and R2 are identical or different organic radicals each having 1 to 18 carbon atoms. RI and R2 are preferably, independently of one another, linear or branched alkyl radicals having 1 to 8 carbon atoms, particularly preferably in each case alkyl radicals such as methyl, ethyl, propyl, isopropyl, butyl or isobutyl radicals and very particularly preferred for ethyl.

The following compounds may be mentioned as examples of compounds of the general formula (IV): maleic acid dimethyl ester, diethyl ester, di-n or isopropyl ester, di-n-butyl ester, di-2-ethyl-hexyl ester or the corresponding fumaric acid ester. Maleic acid diethyl ester is very particularly preferred.

The two-component coating compositions according to the invention contain at least one polyisocyanate component B.

Suitable polyisocyanate components B are organic polyisocyanates with an average NCO functionality of at least 2 and a molecular weight of at least 140 g / mol. Unmodified organic polyisocyanates with a molecular weight of 140 to 300 g / mol, paint polyisocyanates with a molecular weight in the range of 300 to 1000 g / mol, and NCO prepolymers containing more than 400 g / mol of urethane, urea and / or allophanate groups are particularly suitable. mol lying molecular weight or mixtures thereof.

For the purposes of the invention, the term “paint polyisocyanates” is to be understood as meaning compounds or mixtures of compounds which can be obtained from simple polyisocyanates by known oligomerization reactions. Suitable oligomerization reactions are e.g. carbodiimidization, dimerization, trimerization, biuretization, urea formation, urethanization, allophanatization and / or cyclization with the formation of oxadiazine structures. In the case of oligomerization, several of the reactions mentioned can take place simultaneously or in succession.

The "paint polyisocyanates" are preferably biuret polyisocyanates, isocyanurate group-containing polyisocyanates, isocyanurate and uretdione group-containing polyisocyanate mixtures, urethane and / or allophanate group-containing polyisocyanates or isocyanurate and allophanate group-containing polyisocyanates based on simple organic isocyanate groups. Also suitable as polyisocyanate component B are the isocyanate group-containing prepolymers based on simple organic polyisocyanates and / or based on paint polyisocyanates on the one hand and organic polyhydroxy compounds with a molecular weight of over 300 g / mol on the other. While the varnish polyisocyanates containing urethane groups are derivatives of low molecular weight polyols in the molecular weight range from 62 to 300 g / mol, suitable polyols are, for example, ethylene glycol, propylene glycol, trimethylolpropane, glycerol or mixtures of these alcohols, and prepolymer polyhydroxy compounds containing isocyanate groups are prepared using a over 300 g / mol, preferably over 400 g / mol, particularly preferably a molecular weight between 400 and 8000 g / mol, are used. Such polyhydroxyl compounds are in particular those which have 2 to 6, preferably 2 to 3, hydroxyl groups per molecule and are selected from the group consisting of ether, ester, thioether, carbonate and polyacrylate polyols and mixtures of such polyols.

In the preparation of the prepolymers containing isocyanate groups, the higher molecular weight polyols mentioned can also be used in mixtures with the lower molecular weight polyols mentioned, so that mixtures of low molecular weight, urethane group containing paint polyisocyanates and higher molecular weight NCO prepolymers, which are also suitable as inventive polyisocyanate component b) result directly .

To prepare the prepolymers containing isocyanate groups or their mixtures with the paint polyisocyanates, simple organic polyisocyanates of the type mentioned below by way of example or paint polyisocyanates with the higher molecular weight hydroxyl compounds or mixtures thereof with low molecular weight polyhydroxyl compounds of the type mentioned by way of example are used, while maintaining an NCO / OH equivalent ratio of 1.1: 1 to 40 : 1, preferably 2: 1 to 25: 1 converted with urethane and / or allophanate formation. If necessary, when using an excess of distillable simple organic polyisocyanate, this can be removed by distillation following the reaction, so that NCO prepolymers containing monomer-free isocyanate groups are present, which can also be used as polyisocyanate component b).

Examples of suitable simple organic polyisocyanates are 1,4-diisocyanatobutane, 1,5-diisocyanatopentane, 1,6-diisocyanatohexane (HDI), 1,5-diisocyanato-2,2-dimethylpentane, 2,2,4- and 2, 4,4-trimethyl-1,6-diisocyanatohexane, tetramethylxylylene diisocyanate (TMXDI) 1- isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), 1- isocyanato-1-methyl-4- (3) -isocyanatomethylcyclohexane, dicyclohexylmethane-2,4'- and / or 4,4'-diisocyanate, 1,10-diisocyanatodecane, 1,12-diisocyanatododecane, cyclohexane 1,3- and -1,4- diisocyanate, xylylene diisocyanate isomers, triisocyanatononane (TIN), naphthylene-1,5-diisocyanate, 2,4-diisocyanatoluene or its mixtures with 2,6-diisocyanatotoluene with preferably, based on mixtures, up to 35% by weight 2.6 -Diisocyanatotoluene, 2,2'-, 2,4'-, 4,4'-, diisocyanatodiphenyl methane or technical polyisocyanate mixtures of the diphenylmethane series, or any mixtures of the polyisocyanates mentioned.

Preference is given here to aliphatic, cycloaliphatic or araliphatic polyisocyanates selected from the group 1,4-diisocyanatobutane, 1,5-diisocyanatopentane, 1,6-diisocyanatohexane (HDI), 1,5-diisocyanato-2,2-dimethylpentane, 2,2 , 4- or 2,4,4-trimethyl-l, 6- diisocyanatohexane, tetramethylxylylene diisocyanate (TMXDI), l-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), l-isocyanato-l- methyl 4- (3) -isocyanatomethylcyclohexane, dicyclohexylmethane-2,4'- and / or 4,4'-diisocyanate, 1,10-diisocyanatodecane, 1,12-diisocyanatododecane, cyclohexane-1,3- and -1,4 diisocyanate, xylylene diisocyanate isomers, triisocyanatononane (TIN), or any mixtures of such polyisocyanates, are used.

In principle, it is of course also possible to use mixtures of different polyisocyanate components of the aforementioned type.

In addition to the component A containing polyaspartic acid ester, the two-component composition according to the invention can contain further components which are reactive toward isocyanate groups (components C).

This can be, for example, low molecular weight polyols in the molecular weight range from 62 to 300 g / mol, for example ethylene glycol, propylene glycol, trimethylolpropane, glycerol or mixtures of these alcohols, or polyhydroxy compounds one over 300 g / mol, preferably over 400 g / mol, particularly preferably one between 400 and 8000 g / mol lying molecular weight. Such polyhydroxyl compounds are in particular those which have 2 to 6, preferably 2 to 3, hydroxyl groups per molecule and are selected from the group consisting of ether, ester, thioether, carbonate and polyacrylate polyols and mixtures of such polyols.

The two-component composition according to the invention furthermore contains at least one inorganic and / or organic pigment (component Dl), such as, for example, titanium dioxide, zinc oxide, iron oxides, chromium oxides or carbon black. The proportion of pigments in the composition is preferably at least 3% by weight (> 3% by weight), particularly preferably 5 to 40% by weight (> 5 to <40% by weight), very particularly preferably 10 to 35% by weight (> 5 to <40% by weight), based on the total weight of the two-component composition.

A detailed overview of pigments for coatings is given in the "Textbook of Lacquers and Coatings, Volume II, Pigments, Lüllstoffe, Larbstoffe", H. Kittel, Verlag W.A. Colomb in Heenemann GmbH, Berlin-Ober Schwandorf, 1974, pp. 17-265.

In addition, the composition according to the invention can contain further auxiliaries and additives typical for coating technology with polyisocyanate polyaddition compounds, in particular for polyurethane compounds (component D2):

Examples are catalysts / activators such as, for example, titanium, zirconium, bismuth, tin and / or iron-containing catalysts, as described, for example, in WO 05058996. It is also possible to add amines or amidines. The proportion of crosslinking catalyst in the composition is preferably 0.001 to 5% by weight (> 0.001 to <5% by weight), preferably 0.005 to 2% by weight (> 0.005 to <2% by weight), particularly preferred 0.01 to 1% by weight (> 0.01 to <1% by weight), based on the total weight of the two-component

Composition.

Examples of other suitable auxiliaries and additives D2 are paint additives such as light stabilizers such as UV absorbers and sterically hindered amines (HALS), furthermore stabilizers, defoaming agents, anti-cratering agents and / or wetting agents, leveling agents, film-forming auxiliaries, reactive thinners, biocides, solvents or substances for rheology control. The use of light stabilizers, in particular UV absorbers, such as substituted benzotriazoles, S-phenyltriazines or oxalanilides and sterically hindered amines, in particular with 2, 2,6,6-tetramethylpiperidyl structures - referred to as HALS - is described by way of example in A. Valet , Light stabilizers for paints, Vincentz Verlag, Hanover, 1996.

Stabilizers such as radical scavengers and other polymerization inhibitors such as sterically hindered phenols stabilize paint components during storage and are intended to prevent discoloration during curing. Wetting and leveling agents improve surface wetting and / or the flow of paints. Examples are fluorosurfactants, silicone surfactants and special polyacrylates. Rheology-controlling additives are important in order to control the properties of the two-component system during application and in the flow phase on the substrate and are known, for example, from patent specifications WO 9422968, EP0276501, EP0249201 or WO 9712945. Furthermore, water scavenger, such as Triethyl orthoformate, toluenesulfoisocyanate, monooxazolidines or molecular sieves, and anti-hydrolysis agents, such as, for example, carbodiimides, can be used. The proportion of paint additives in the composition is preferably 0.5 to 15% by weight (> 0.5 to <15% by weight), preferably 1 to 10% by weight (> 1 to <10% by weight) ), particularly preferably 2 to 7% by weight (> 2 to <7% by weight), based on the total weight of the two-component composition. A detailed overview of paint additives can be found in the "Textbook of paints and coatings, Volume III, solvents, plasticizers, additives, intermediate products", H. Kittel, Verlag WA Colomb in Heenemann GmbH, Berlin-Oberschwandorf, 1976, p. 237- 398

Further auxiliaries and additives D2 are fillers. Suitable fillers are, for example, heavy spar, chalk or talc. Furthermore, fillers with a barrier effect can be used, e.g. Platelet-shaped sheet silicates or sheet aluminosilicates, graphite, aluminum flakes or barrier pigments such as iron mica and nanofillers such as e.g. Clays and aluminum silicates. The fillers can be used alone or in combination. The proportion of filler in the coating is preferably 1 to 30% by weight (> 1 to <30% by weight), preferably 3 to 20% by weight (> 3 to <20% by weight), particularly preferred 5 to 15% by weight (> 5 to <15% by weight), based on the total weight of the two-component composition. A detailed overview of fillers for coatings is given in the "Textbook of Lacquers and Coatings, Volume II, Pigments, Fillers, Dyes", H. Kittel, Verlag W.A. Colomb in Heenemann GmbH, Berlin-Oberschwandorf, 1974, pp. 17-265.

Solvents are also considered auxiliaries and additives D2. The solvent can be an organic solvent or a mixture of organic solvents or water or a mixture of organic solvent (s) and water. Suitable solvents are to be used in a manner known to the person skilled in the art, tailored to the composition and the application method. Solvents should dissolve the components used and promote their mixing and avoid incompatibilities. Furthermore, during application and curing, they should leave the coating in a manner matched to the crosslinking reaction taking place, so that a solvent-free coating with the best possible appearance and without defects such as pits or pinholes is created. Solvents that are used in two-component technology are particularly suitable. Examples of organic solvents are ketones such as acetone, methyl ethyl ketone or hexanone, esters such as ethyl acetate, butyl acetate, methoxyproyl acetate, substituted glycols and other ethers, aromatics such as xylene or solvent naphtha such as from Exxon-Chemie and mixtures of the solvents mentioned. If the NCO-reactive part of the composition is in the form of an aqueous dispersion, water is also suitable as a solvent or diluent. If present, the proportion of solvent in the composition is preferably 0.5 to 40% by weight (> 0.5 to <40% by weight), preferably 1 to 30% by weight (> 1 to <30% by weight), particularly preferably 2 to 25% by weight (> 2 to <25% by weight), based on the total weight of the two-component composition.

The ratio of the polyisocyanate component B to the polyaspartic acid ester-containing component A in the composition, based on the amounts of moles of the polyisocyanate groups to the NCO-reactive groups, is preferably from 0.5 to 1.0 to 3.0 to 1.0. A ratio of 0.9 to 1.0 to 1.5 to 1.0 is particularly preferred. A ratio of 1.05 to 1.0 to 1.25 to 1.0 is very particularly preferred.

The two-component composition according to the invention is preferably not a foamable or foam-forming composition. The composition is preferably not radically polymerizable, especially not photo-polymerizable, i. the composition does not harden through radical processes, in particular not through radical polymerization processes which are initiated by actinic radiation.

The two-component coating composition according to the invention is produced by methods known per se in the technology of lacquers and coatings.

An isocyanate-reactive (R) and an isocyanate-containing component (H) are first produced separately by mixing the respective isocyanate-reactive components A and C, or by mixing the respective polyisocyanate components B. The auxiliaries and additives D1 and D2 are preferably added to the isocyanate-reactive component R. The components R and H produced in this way are only mixed immediately before or during application. If mixing takes place before application, it must be ensured that the reaction of the components starts after mixing. Depending on the choice of components and additives, the reaction will take place at different speeds. The processing time within which the composition must be applied, also referred to as the pot life and defined as the time from the mixing of the components to doubling the initial viscosity and / or the flow time (determined in accordance with DIN EN ISO 2431: 2012-03, but using a DIN 4 flow cup), then takes between 1 minute and 24 hours, usually in the range of 10 minutes to 8 hours, depending on the selection of the components. The pot life is determined by methods known to those skilled in the art.

In a preferred embodiment, the isocyanate-reactive components are mixed, optionally accompanied by or followed by dispersion, and then rubbed. The latter can be done using a bead mill, for example. The grinding can be followed by a sieving step. The invention also relates to a method for coating a substrate, which comprises at least the following steps: i) applying the two-component coating described above

composition on at least a portion of a substrate to be coated and ii) curing the coating composition from step i).

Further objects of the present invention are therefore the use of the two-component coating compositions according to the invention for producing coatings on substrates, the above-described process for coating a substrate, and the coated substrates themselves obtainable in this way.

The substrates can already be completely or partially coated with one or more layers of lacquer. These lacquer layers can still be uncured or moist, partially cured or fully cured, and the further lacquer layers on the substrate are preferably partially or fully cured. Examples of lacquer layers are primers, primers, fillers, fillers, base lacquers or substrates that have already been completely lacquered, which are coated again after any pretreatment such as sanding or plasma activation.

The two-component coating compositions are used in particular to produce coatings for corrosion protection, general industrial painting and for use in the ACE (Agriculture, Construction and Earth moving equipment) sector. The coatings are preferably top coatings.

Further, preferred objects of the present invention are therefore the use of the above-described two-component coating compositions for producing top coatings on substrates, the above-described method for coating substrates with these top coatings, and the coated substrates themselves obtainable in this way.

Another subject is the use of top coatings in the field of corrosion protection, general industrial painting or as ACE coatings.

The coating composition can be applied by conventional application methods. Examples of application methods are brushing, brushing, roller application, knife coating, dipping and spraying; spray application is preferred. After the application, after an optional flash-off time, the curing or drying of the inventive compounds follows Composition on the substrate or object. This takes place according to the methods customary in coating technology either under ambient conditions with regard to temperature and humidity or under forced conditions, for example by increasing the temperature in ovens, using radiation such as infrared, near-infrared or microwave radiation, and using dehumidified and / or heated air or others Gases. It is preferable to forego the use of devices for forced curing. The applied coating composition is cured, for example, at temperatures from -20 to 100 ° C, preferably from -10 to 80 ° C, more preferably from 0 to 60 ° C and most preferably from 10 to 40 ° C. Although not preferred, lower cure temperatures can also be used but will result in longer cure times.

It is also possible, although not preferred, to cure the composition at higher temperatures, for example 80 to 160 ° C. or higher. After the first coating has hardened, a further coating can be applied and also hardened.

Another object of the invention is the use of the two-component coating compositions for the production of gloss-stable coatings.

Experimental part

Raw materials and substrates:

PACM 20: a mixture of 2,4 and 4,4'-diaminodicyclohexyl methane, manufactured by Evonik

Desmodur N 3600: a low-viscosity HDI trimer with approx. 23% NCO and <0.25% free HDI, manufacturer Covestro

Desmodur XP 2489: an aliphatic polyisocyanate based on HDI and isophorone diisocyanate trimer with approx. 21% NCO, manufacturer Covestro

UOP F powder: molecular sieve, Honeywell UOP, USA

Byk A 530: Defoamer, Byk-Chemie GmbH, Germany

Disperbyk 163: Dispersant, Byk-Chemie GmbH, Germany

Titanium dioxide R-KB-4: pigment, various suppliers

Chromium oxide green GN: pigment, various suppliers

Iron oxide yellow 415: pigment, various suppliers

Heucophos® ZPA: Corrosion protection pigment, Heubach GmbH, Germany

Barite EWO: barite filler, Sachtleben, Germany

Microtalc IT Extra: Talc filler, Mondo Minerals, the Netherlands

CAB-O-SIL TS 720: Rheology additive, Cabot Airgel, Germany

Tinuvin 292: light stabilizer, BASF, Germany

Solvent: Solvesso 100, 1-methoxy-2-propyl acetate (MPA) and butyl acetate (BA), Azelis, Germany

Methods:

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

GC-MS measurements were made with a 6890 gas chromatograph and mass spectrum detector 5973 from Agilent with standard ionization (electron impact) with 70 eV, a standard GC capillary (100% polysiloxane phase) and split injection at 250.degree Injector temperature carried out. The% areas of the gas chromatogram were evaluated. All viscosity measurements were carried out with a Physica MCR 51 rheometer from Anton Paar Germany GmbH (Germany) according to DIN EN ISO 3219: 1994-10 at 23 ° C.

The Hazen color numbers were determined on a LICO 400 color measuring device from Hach Fange GmbH (Germany) in accordance with DIN EN ISO 6271: 2016-05.

The amine numbers were determined titrimetrically in accordance with EN ISO 9702: 1998 (perchloric acid method) with the exception that the results were given as amine numbers. The amine number in mg KOH / g was calculated using the following equation:

(a-b) x 5.61

Amine number = - - a: the consumption, in milliliters, of perchloric acid, concentration c = 0.1 mol / 1 (included in the factor 5.61), in the main experiment;

b: the consumption, in milliliters, of perchloric acid, concentration c = 0.1 mol / 1 (included in the factor 5.61), in the blank test;

E: the weight, in grams.

The flow times were determined according to 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 it took for the viscosity to double.

The drying was determined in accordance with DIN EN ISO 9117-5: 2012-11 on glass.

Weathering took place in accordance with DIN EN ISO 16474/2: 2014-03, method A, cycle 1 (102: 18) or DIN EN ISO 16474/3: 2014-03 method C, cycle 4 (UVB). Single-layer top coats were tested on unsanded aluminum.

The gloss values were determined using a reflectometer in accordance with the DIN EN ISO 2813: 2015-02 standard.

The pendulum hardness was measured in accordance with DIN EN ISO 1522: 2007-04 using a König pendulum on glass. The spray application was carried out with a spray gun of the type SATAjet RP 3000 with a SATA spray nozzle 1.6 mm at a pressure of approx. 2.1 to 2.2 bar. It was painted in the existing room climate (slight fluctuations in temperature and humidity possible).

Salt spray test was carried out in accordance with DIN EN ISO 9227: 2012-09 using the NSS method on samples scratched in accordance with ISO 17872. One-layer and two-layer top coatings were applied to a steel sheet (blasted SA 2Vi). The blistering was assessed in accordance with DIN EN ISO 4628-2: 2016-07 (n / a = no change / leaf = amount of bubbles / size = bubble size). The delamination and corrosion were assessed according to ISO 4628-8: 2012-3.

The condensation test was carried out in accordance with DIN EN ISO 6270-2: 2005-09. The evaluation of the bubble formation was carried out according to DIN EN ISO 4628-2: 2016-07 (n / a = no change / sheet = amount of bubbles / size = bubble size)

Cross-cut test was carried out in accordance with DIN EN ISO 2409: 2006-13.

The front pull test was carried out according to DIN EN ISO 4624: 2016-08 procedure B.

The tensile stress and the type of break were determined according to the following criteria:

A cohesive break in the substrate;

A / B adhesion break between substrate and first coating;

B cohesive failure in the first coating;

B / C Adhesion break between first and second coating; judged.

Manufacture of pigmented top coats

The top coats were produced at room temperature by placing the constituents of component 1 in a cooled vessel (double-walled vessel with external cooling by cold tap water) and predispersing them at approx. 600-800 rpm with a dissolver and then grinding them in a bead mill and then sifted. Component 1 was processed after one day of maturation.

Component 2 was then added with slow stirring (approx. 600-800 rpm) and then at 2000 rpm for 1 minute (coatings 1) or 2800 rpm. dispersed for 30 minutes (Coatings 2). Single-layer construction

The top coatings used were applied with the spray application described to a sheet steel (blasted SA 2Vi) or a sanded aluminum plate and applied at 23 ° C / 50% rel. Humidity dried.

Two-layer construction

A 1K PUR zinc dust basecoat based on the standard formulation from Covestro Deutschland AG with the designation RR 5280 was applied to a sheet steel (blasted SA 2Vi) using the spray application described. After this base coat had dried, the top coat was also applied with the described spray application and applied at 23 ° C / 50% rel. Humidity dried.

Polyaspartic acid ester PAS 1

Commercially available polyaspartic acid ester from Covestro under the name Desmophen NH 1420.

Characteristics:

Monoamines of the formula (II) (GC-MS): 4.0%

Diethyl fumarate (GC) 2.9 percent by weight

Viscosity 1220 mPas

Color number 27 APHA

Amine number 201 mg KOH / g

Polyaspartic acid ester PAS 2

341.8 g of PACM 20 were initially introduced at 23 ° C. under dry nitrogen and stirring. 560.0 g of diethyl maleate were added dropwise in such a way that the temperature did not rise above 60.degree. After the addition had ended, the temperature was adjusted to 45 ° C. and the batch was stirred at 45 ° C. for 2 hours. The batch was then stored at 23 ° C. for 7 weeks. The diethyl fumarate content after storage was 3.0 percent by weight. Diethyl fumarate was then distilled off at 120 ° C. and 0.2 mbar. A light-colored product was obtained with the following characteristics:

Monoamines of the formula (II) (GC-MS): 4.2%

Diethyl fumarate (GC) 0.05 percent by weight

Viscosity 1860 mPas

Color number 19 APHA

Amine number 203 mg KOH / g Polyaspartic acid ester PAS 3

341.8 g of PACM 20 were initially introduced at 23 ° C. under dry nitrogen and stirring. 560.0 g of diethyl maleate were added dropwise in such a way that the temperature did not rise above 60.degree. After the addition had ended, the temperature was adjusted to 45 ° C. and the batch was stirred at 45 ° C. for 2 hours. The batch was then stored at 23 ° C. for 9 weeks. The diethyl fumarate content after storage was 2.7 percent by weight. Diethyl fumarate was then distilled off at 120 ° C. and 0.2 mbar. A light-colored product was obtained with the following characteristics:

Monoamines of the formula (II) (GC-MS) 5.3%

Diethyl fumarate (GC) 0.09 percent by weight

Viscosity 1810 mPas

Color number 27 APHA

Amine number 206 mg KOH / g

Polyaspartic acid ester PAS 4

341.8 g of PACM 20 were initially introduced at 23 ° C. under dry nitrogen with stirring. 567.6 g of diethyl maleate were added dropwise in such a way that the temperature did not rise above 60.degree. After the addition had ended, the temperature was adjusted to 45 ° C. and the batch was stirred at 45 ° C. for two hours. The batch was then stored at 23 ° C. for 30 hours. The diethyl fumarate content 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 with the following characteristics:

Monoamines of the formula (II) (GC-MS): 13.2%

Diethyl fumarate (component A, GC) <0.03% by weight

Viscosity 1650 mPas

Color number 5 APHA

Amine number 213 mg KOH / g

Polyaspartic acid ester PAS 5

341.8 g of PACM 20 were initially introduced at 23 ° C. under dry nitrogen with stirring. To this, 1678.8 g of diethyl maleate were added dropwise in such a way that the temperature did not rise above 60.degree. After the addition had ended, the temperature was adjusted to 45 ° C. and the batch was stirred at 45 ° C. for one hour. The batch was then stored at 23 ° C. for 24 hours. Diethyl fumarate was then distilled off at 120 ° C. and 0.2 mbar. A light-colored product was obtained with the following characteristics: Monoamines of the formula (II) (GC-MS): 9.3%

Diethyl fumarate (component A, GC) 0.07% by weight

Viscosity 1710 mPas

Color number 21 APF1A

Amine number 209 mg KOFl / g

The polyaspartic acid esters PAS 1, 2, 3 and PAS 5 were formulated into topcoats as shown in Tables 1 and 7.

Table 1. Composition of the top coats 1

The pot life and drying of the top coats from Examples 1 to 8 are summarized in Tables 2 and 3.

5

Table 2. Drying and pot life of the top coats from Examples 1 to 6.

Table 3. Drying and pot life of the top coats from Examples 7 and 8.

As can be seen from Table 2, the coating compositions according to the invention have faster drying and at the same time a longer pot life in comparison to the coating composition based on conventional polyaspartic esters. The coating compositions according to the invention shown in Table 3 also have a longer pot life with constant rapid drying.

The cured top coatings from Examples 4, 5, 7, and 8 were also subjected to weathering. The results are shown in Tables 4-6. Table 4. UV-B test of the coatings from Examples 4 and 5.

Table 5. Xenon test of the coatings from Examples 4 and 5.

Table 6. Xenon test of the coatings from Examples 7 and 8.

As the weathering results show, the coating compositions according to the invention show a slower decrease in gloss and a higher or at least as high residual gloss compared to the coating composition based on conventional polyaspartic esters. Table 7. Composition of the top coats 2

Table 8. Drying and pot life of the top coats from Examples 9 to 14.

Table 8 confirms that the coating compositions according to the invention are not only distinguished by good chemical resistance but also by faster drying and at the same time a longer pot life compared to the coating composition based on conventional polyaspartic esters.

The cured coatings 9 to 14 were then subjected to both a condensation water test and a salt spray test.

Table 9. Salt spray test and condensation test of the top coatings from Examples 9 to 11 (structure: one-layer on steel, blasted Sa 2 1/2).

Table 10. Salt spray test and condensation test of the top coatings from Examples 12 to 14 (construction: two-layer on steel, blasted Sa 2 1/2).

These results show that the coating compositions according to the invention contribute to obtaining resistant corrosion protection formulations.

The cured coatings 9 to 14 were then exposed to weathering.

Table 11. UV-A and UV-B tests of the coatings from Examples 9 to 11. Table 12. UV-A and UV-B tests of the coatings from Examples 12 to 14.

The top coatings 2 based on coating compositions according to the invention are also characterized by a slower decrease in gloss and a higher or at least equal residual gloss compared to the top coatings 2 based on conventional polyaspartic esters.

Claims

1. Two-component coating compositions (2K coating agents), containing a) at least one component A containing polyaspartic acid ester,

b) at least one polyisocyanate component B

d) at least one inorganic and / or organic pigment, preferably in a proportion of at least 3% by weight, based on the total weight of the two-component composition (component Dl) and

optionally containing further auxiliaries and additives (component D2), component A corresponding to compositions

one or more polyaspartic acid esters of the general formula (I)

(I),

in which

X represents an m-valent organic radical, optionally containing one or more heteroatoms, as obtained by removing the primary amino groups from a corresponding polyamine having (cyclo) aliphatically or araliphatically bound primary amino groups and having a molecular weight range of 60 to 6000 g / mol can, and the further, isocyanate-reactive and / or at temperatures up to 100 ° C inert functional groups can contain,

R1 and R2 stand for identical or different organic radicals, each with 1 to 18 carbon atoms,

m stands for an integer> 1,

and optionally one or more polyaspartic acid esters with a primary amino group of the general formula (II)

in which

n stands for m-1,

X, radicals RI and R2 have the meanings given above,

characterized in that dialkyl fumarate is present in component A in an amount of 0.01 to 1.2% by weight, based on the total weight of component A.

2. Two-component coating compositions (2K coating agents) according to

Claim 1, characterized in that fumaric acid dialkyl ester is present in component A in an amount of 0.01 to 1% by weight, based on the total weight of component A.

3. Two-component coating compositions (2K coating agents) according to

Claim 1, characterized in that dialkyl fumarate is present in component A in an amount of 0.01 to 0.1% by weight, based on the total weight of component A.

4. Two-component coating compositions (2K coating agents) according to one of claims 1 to 3, wherein the polyaspartic acid ester-containing component A does not contain any compounds of the formula II.

5. Two-component coating compositions (2K coating agents) according to one of claims 1 to 3, wherein the polyaspartic acid ester-containing component A contains compounds of the formula II.

6. Two-component coating compositions (2K coating agents) according to one of claims 1 to 3 or 5, wherein the polyaspartic acid ester-containing component A contains one or more compounds of the formula II and the proportion of the compound (s) of the formula II is at least 0.1% GC surface area (measured as area% in the gas chromatogram), the sum of the GC surface areas of the compounds of the two general formulas (I) and (II) being 100%.

7. Two-component coating compositions (2K coating agents) according to one of claims 1 to 3 or 5, wherein the polyaspartic acid ester-containing component A contains one or more compounds of the formula II and the proportion of the compound (s) of the formula II is at least 1% of the GC surface (measured as area% in the gas chromatogram), the sum of the GC surfaces of the compounds of the two general formulas (I) and (II) being 100%.

8. Two-component coating compositions (2K coating agents) according to any one of claims 5 to 7, the proportion of the compound (s) of the formula II being a maximum of 20% of the GC surface.

9. A method for producing a coating on a substrate, comprising at least the following steps:

i) applying a two-component coating composition according to any one of claims 1 to 8 to at least part of a substrate to be coated and ii) curing the coating composition from step i).

10. Substrates coated with a coating obtainable by a method according to claim 9.

11. A method for producing a coating on a substrate according to claim 9, or substrates coated with a coating according to claim 10, characterized in that the coating is a top coating.

12. Use of a two-component coating composition (2K-

Coating agent) according to one of claims 1 to 8 for the production of coatings, or method for producing a coating on a substrate according to claim 9 or 11, or substrates coated with a coating according to claim 10 or 11, wherein the coatings are in the area of corrosion protection or the general industrial coatings or ACE coatings (Agriculture, Construction and Earth moving equipment).

13. Use of a two-component coating composition (2K-

Coating agent) according to one of claims 1 to 8 for the production of gloss-stable coatings.