EP2598549A1 - High-functionality polyisocyanates having urethane groups - Google Patents

Abstract

The present invention relates to novel polyisocyanates which comprise urethane groups and which are based on aliphatic and/or cycloaliphatic diisocyanates, and their use.

Description

 Highly functional urethane-containing polyisocyanates

The present invention relates to novel urethane group-containing polyisocyanates based on aliphatic and / or cycloaliphatic diisocyanates and their use.

EP1091991 B1 describes two-component polyurethane mixtures with a highly functional, preferably at least four-functional, polyisocyanate as the A component and a polyol as the B component. The B component may also contain low molecular weight di- to penta-alcohols.

Polyisocyanate and polyol are used only in an NCO: OH ratio of 0.6 to 1.4: 1, since the mixtures are coating compositions for coatings in which substantially all reactive groups are to be reacted after curing.

EP 1497351 B1 describes the preparation of highly functional polyisocyanates by trimerization of a mixture comprising aliphatic diisocyanates and uretdiones. Alcohols are not present.

EP 1061091 A describes at least difunctional polyisocyanates with allophanate groups by reaction of polyisocyanates with a monoalcohol and optionally higher-functional diols or polyols. The disadvantage of this is that no more than two polyisocyanates can be linked together by means of an allophanate bond and thereby you limited functionality of the resulting products.

EP 620237 A2 describes prepolymers of diisocyanates and polyols. Reaction with higher-functional polyisocyanates is not disclosed.

The disadvantage of this is that the NCO functionality of the resulting products is not higher than the OH functionality of the polyols used. DE-OS 2305695 describes prepolymers of diisocyanates and low molecular weight polyols having 2 to 4 hydroxyl groups.

Reaction with higher functional polyisocyanates is not disclosed. The object of the present invention was to provide novel polyisocyanates having a high functionality for paints, especially for clearcoats, which have a high hardness and / or scratch resistance, in particular already when cured at low temperatures and / or in bicomponent. Component polyurethane coatings show accelerated drying and / or improved sulfuric acid resistance.

The object is achieved by highly functional urethane-containing polyisocyanates obtainable by

 - Implementation of at least one tertiary di- or Trialkanolamins (A) with

 at least one polyisocyanate (B) having a functionality of more than 2, which has at least one isocyanurate, biuret, uretdione and / or allophanate group and is composed of aliphatic and / or cycloaliphatic isocyanates,

under reaction conditions under which urethane groups are formed between (A) and (B), with the proviso that

 - The molar ratio of NCO groups to OH groups between (B) and (A) is at least 3: 1. The compound (A) may be a tertiary dialkanolamine or a trialkanolamine.

In the context of this document, a trialkanolamine is understood to mean the reaction product of ammonia with propylene oxide and / or ethylene oxide, preferably propylene oxide or ethylene oxide, particularly preferably ethylene oxide.

Preferred trialkanolamines (A) are those of the formula

wherein η, ο, ρ independently of one another each represent an integer from 1 to 5, preferably 1 to 3, particularly preferably 1 to 2 and very particularly preferably 1 and each X, for i = 1 to n, 1 to o and 1 to p can be independently selected from the group -CH ₂ -CH ₂ -0-, -CH ₂ -CH (CH ₃ ) -O- and -CH (CH ₃ ) -CH ₂ -O- and preferably -CH ₂ -CH ₂ -0- means.

In a preferred embodiment, the trialkanolamine (A) is 5- [bis (2'-hydroxyethyl) amino] -3-oxa-pentane-1-ol, triethanolamine or tripropanolamine, more preferably triethanolamine. In the context of this document, a tertiary dialkanolamine is understood to mean the reaction product of a primary amine with propylene oxide and / or ethylene oxide, preferably propylene oxide or ethylene oxide, particularly preferably ethylene oxide. Preferred tertiary dialkanolamines are

wherein R ^{1 is} a straight or branched Ci to C 20 alkyl group, an optionally substituted C 5 to C 12 cycloalkyl group, an optionally substituted C ₇ - to Cio-aralkyl group, or an optionally substituted C6-Ci2-aryl group, q and r is independently of one another in each case an integer from 1 to 5, preferably 1 to 3, particularly preferably 1 to 2 and very particularly preferably 1, and each X, for i = 1 to q and 1 to r can be selected independently of one another the group -CH ₂ -CH ₂ -O-, -CH ₂ -CH (CH ₃ ) -O- and -CH (CH ₃ ) -CH ₂ -O- and preferably -CH ₂ -CH ₂ -O-. Therein a straight-chain or branched C 1 - to C 20 -alkyl group mean, for example, methyl,

Ethyl, propyl, isopropyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, 2,4,4-trimethylpentyl, decyl, 1, 1-dimethylpropyl , 1, 1-dimethylbutyl or 1, 1, 3,3-tetramethylbutyl, an optionally substituted C5 to C12-cycloalkyl group, cyclopentyl, cyclohexyl, cyclooctyl, cyclododecyl, methylcyclopentyl, dimethylcyclopentyl, methylcyclohexyl, dimethylcyclohexyl, diethylcyclohexyl, butylcyclohexyl , Methoxycyclohexyl,

Dimethoxycyclohexyl, diethoxycyclohexyl, butylthiocyclohexyl, chlorocyclohexyl, dichlorocyclohexyl, dichlorocyclopentyl and a saturated or unsaturated bicyclic system such as norbornyl or norbornenyl, an optionally substituted C ₇ to C 10 aralkyl group, for example benzyl,

1-phenylethyl, 2-phenylethyl, α, α-dimethylbenzyl, benzhydryl, p-tolylmethyl, 1- (p-butylphenyl) -ethyl, o-, m- or p-chlorobenzyl, 2,4-dichlorobenzyl, o-, m or p-methoxybenzyl or o-, m- or p-ethoxybenzyl, an optionally substituted C6-Ci2-aryl group, for example phenyl, 2-, 3- or 4-methylphenyl, α-naphthyl or ß-naphthyl.

Among these radicals, R ¹ is preferably a C 5 - to C 12 -cycloalkyl or C ¹ - to C 20 -alkyl, more preferably C 5 - to C 6 -cycloalkyl or C 1 - to C 10 -alkyl, very particularly preferably C 1 - to C 12 -alkyl and in particular C 1 - to C 4 -alkyl.

Preferred for R ¹ are methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, phenyl, α- or ß-naphthyl, benzyl , Cyclopentyl or cyclohexyl.

Particularly preferred radicals R ¹ are methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, 2-ethylhexyl, cyclopentyl or cyclohexyl. Very particular preference is given to methyl, ethyl, n-propyl, isopropyl and n-butyl.

Examples of tertiary dialkanolamines N-ethyldiethanolamine, N-methyldiethanolamine, N-butyldiethanolamine, N-cyclopentyldiethanolamine, N-cyclohexyldiethanolamine, N-ethyldipropanolamine, N-methyldipropanolamine and N-butyldipropanolamine.

Preference is given to N-ethyldiethanolamine, N-methyldiethanolamine and N-butyldiethanolamine, particularly preferably N-ethyldiethanolamine and N-methyldiethanolamine.

It is optionally possible to use at least one diol (A1) and / or polyol (A2) in addition to the compound (A), for example in amounts such that up to 70% of the total amount of hydroxyl groups used is selected from the diol (A1 ) and / or polyol (A2), for example 10 to 70%, preferably 15 to 55% and particularly preferably 20 to 40%.

Polyols (A2) have a functionality of at least 3, for example 3 to 6, preferably 3 to 4, particularly preferably 3 or 4 and very particularly preferably 3.

Examples of polyols (A2) are trimethylolbutane, trimethylolpropane, trimethylolethane, pentaerythritol, glycerol, ditrimethylolpropane, dipentaerythritol, sorbitol, mannitol, diglycerol, threitol, erythritol, adonite (ribitol), arabitol (lyxite), xylitol, dulcitol (galactitol), Maltitol and isomalt.

Preference is given to polyols having a functionality between 3 and 4, particularly preferably those having a functionality of 3.

Preferred polyols are trimethylolpropane, trimethylolethane, pentaerythritol, glycerol, ditrimethylolpropane and dipentaerythritol, particular preference is given to trimethylolpropane, pentaerythritol and glycerol, very particular preference to trimethylolpropane and glycerol. Examples of diols (A1) are aliphatic diols which have from 2 to 20, preferably 2 to 12, carbon atoms, more preferably 1, 2-ethanediol, 2,2-dimethyl-1,2-ethanediol, 1,2-propanediol, 1, 3-propanediol, 2,2-dimethyl-1, 3-propanediol, 2-methyl-1,3-propanediol, 2-ethyl-1,3-propanediol, 2-ethyl-2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1, 2-butanediol, 1, 3-butanediol, 1, 4-butanediol, 3-methylpentan-1, 5-diol, 1, 6-hexanediol, 2- Ethyl 1,3-hexanediol, 2-propyl-1,3-heptanediol, 1,8-octanediol, 2,4-diethyloctane-1,3-diol, 1,10-decanediol, or cycloaliphatic diols which are six to 20 carbon atoms, preferably bis (4-hydroxycyclohexane) isopropylidene, tetramethylcyclobutanediol, 1, 2-, 1, 3- or 1, 4-cyclohexanediol, cyclooctanediol, norbornanediol, 2,2-bis (4-hydroxycyclohexyl) propane, 1 , 1, 1, 2, 1, 3 and 1, 4-cyclohexanedimethanol.

Among these, the aliphatic diols are preferred, preferably 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,4-butanediol, 1,6 Hexanediol, 2-ethyl-1,3-hexanediol and 2-propyl-1,3-heptanediol, more preferably 2,2-dimethyl-1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 2 Ethyl-1, 3-hexanediol and 2-propyl-1, 3-heptanediol, most preferably 1, 4-butanediol and 1, 6-hexanediol.

It is a preferred embodiment of the present invention to use the polyol (A2) in alkoxylated form.

An alkoxylated polyol is understood to mean a polyol which is formally reacted with one or more identical or different alkylene oxides on at least one hydroxy group. Suitable alkylene oxides for such an alkoxylation are, for example, ethylene oxide, propylene oxide, n-butylene oxide, isobutylene oxide, vinyl oxirane and / or styrene oxide.

The alkylene oxide chain may preferably be composed of ethylene oxide, propylene oxide and / or butylene oxide units. Such a chain may be composed of a species of alkylene oxide or a mixture of alkylene oxides. When a mixture is used, the different alkylene oxide units may be random or block or blocks of individual species. Preferred as the alkylene oxide is ethylene oxide, propylene oxide or a mixture thereof, particularly preferably either ethylene oxide or propylene oxide and most preferably ethylene oxide.

The number of alkylene oxide units in the chain is, for example, 1 to 10, preferably 1 to 5, particularly preferably 1 to 4 and in particular 1 to 3, based on the particular hydroxyl groups of the polyol.

Particular preference is given to alkoxylated polyols of the formulas (IIa) to (IIc)

(IIa) (IIb) (Nc)

wherein

R ^{2 is} hydrogen or C 1 -C 6 -alkyl, k, I, m, q independently of one another are each an integer from 1 to 10, preferably 1 to 5, particularly preferably 1 to 4 and very particularly preferably 1 to 3 and each X, for i = 1 to k, 1 to 1, 1 to m and 1 to q can be selected independently of one another from the group -CH ₂ -CH ₂ -0-, -CH ₂ -CH (CH ₃ ) -0- , -CH (CH ₃ ) -CH ₂ -O-, -CH ₂ -C (CH ₃ ) ₂ -O-, - C (CH ₃ ) ₂ -CH ₂ -O-, -CH ₂ -CHVin-O- , -CHVin-CH ₂ -0-, -CH ₂ -CHPh-O- and -CHPh-CH ₂ -O-, preferably from the group -CH ₂ -CH ₂ -O-, -CH ₂ -CH (CH ₃ ) -O- and -CH (CH ₃ ) -CH ₂ -O-, and more preferably -CH ₂ -CH ₂ -O-, wherein Ph is phenyl and Vin is vinyl.

These are preferably one to five times, more preferably one to four times and very particularly preferably one to three times ethoxylated, propoxylated or mixed ethoxylated and propoxylated and in particular exclusively ethoxylated or especially unalkoxylated glycerol, trimethylolpropane, trimethylolethane or pentaerythritol.

The ratio of diols (A1) to polyols (A2) is preferably from 10:90 to 90:10 (based on the molar amounts of diol and polyol), particularly preferably from 20:80 to 80:20, very particularly preferably from 30 : 70 to 70:30 and especially from 40:60 to 60:40.

The polyisocyanate (B) has a functionality of more than 2, preferably at least 2.2, particularly preferably at least 2.4, very particularly preferably at least 2.8 and in particular at least 3. The polyisocyanates (B) are composed of aliphatic and / or or cycloaliphatic, preferably either aliphatic or cycloaliphatic diisocyanates.

The diisocyanates are preferably isocyanates having 4 to 20 C atoms. Examples of customary diisocyanates are aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate (1,6-diisocyanatohexane), octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate, derivatives of lysine diisocyanate, trimethylhexane diisocyanate or tetramethylhexane diisocyanate, cycloaliphatic diisocyanates such as 1, 4-, 1, 3 or 1, 2-diisocyanatocyclohexane, 4,4'- or 2,4'- Di (isocyanatocyclohexyl) methane, 1-isocyanato-3,3,5-trimethyl-5- (isocyanatomethyl) cyclohexane (isophorone diisocyanate), 1, 3- or 1, 4-bis (isocyanatomethyl) cyclohexane or 2,4-, or 2 , 6- diisocyanato-1-methylcyclohexane and 3 (or 4), 8 (or 9) -bis (isocyanatomethyl) - tricyclo [5.2.1 .0 ^{2 6} ] decane isomer mixtures.

Preferred diisocyanates are 1,6-hexamethylene diisocyanate, isophorone diisocyanate and / or 4,4'- or 2,4'-di (isocyanatocyclohexyl) methane, particular preference is given to 1,6-hexamethylene diisocyanate and / or isophorone diisocyanate and very particular preference to 1,6 -Hexamethylendiisocyanat.

There may also be mixtures of said diisocyanates.

Suitable polyisocyanates are polyisocyanates containing isocyanurate groups, uretdione diisocyanates, polyisocyanates containing biuret groups, polyisocyanates containing urethane and / or allophanate groups of linear or branched C 4 -C 20 -alkylene diisocyanates or cycloaliphatic diisocyanates having a total of 6 to 20 carbon atoms or mixtures thereof ,

The usable polyisocyanates preferably have a content of isocyanate groups (calculated as NCO, molecular weight = 42 g / mol) of 10 to 60% by weight, based on the diisocyanate and polyisocyanate (mixture), preferably 12 to 50% by weight and especially preferably 12 to 40% by weight.

Particularly preferred are hexamethylene diisocyanate, 1, 3-bis (isocyanatomethyl) cyclohexane, isophorone diisocyanate and di (isocyanatocyclohexyl) methane or its polyisocyanates, very particularly preferably isophorone diisocyanate and hexamethylene diisocyanate or their polyisocyanates, particularly preferably hexamethylene diisocyanate or its polyisocyanates.

Also preferred are 1) isocyanurate-containing polyisocyanates of aliphatic and / or cycloaliphatic diisocyanates. Particular preference is given here to the corresponding aliphatic and / or cycloaliphatic isocyanato-isocyanurates and in particular those based on hexamethylene diisocyanate and / or isophorone diisocyanate. The isocyanurates present are, in particular, tris-isocyanatoalkyl or trisisocyanatocycloalkyl isocyanurates, which are cyclic trimers of the diisocyanates, or mixtures with their higher homologs having more than one isocyanurate ring. The isocyanato-isocyanurates generally have an NCO content of 10 to 30 wt .-%, in particular 15 to 25 wt .-% and an average NCO functionality of 2.6 to 4.5.

2) uretdione diisocyanates having aliphatically and / or cycloaliphatically bonded isocyanate groups and in particular those of hexamethylene diisocyanate or isophorone diisocyanate naturally derived. Uretdione diisocyanates are cyclic dimerization products of diisocyanates.

The uretdione diisocyanates can be used as polyisocyanates (B) in admixture with other polyisocyanates, in particular those mentioned under 1).

3) biuret polyisocyanates having cycloaliphatic or aliphatic bound isocyanate groups, in particular tris (6-isocyanatohexyl) biuret or mixtures thereof with its higher homologs. These biuret polyisocyanates generally have an NCO content of 18 to 22 wt .-% and an average NCO

Functionality from 2.8 to 4.5.

4) polyisocyanates containing urethane and / or allophanate groups with aliphatically or cycloaliphatically bonded isocyanate groups, as obtained, for example, by reacting excess amounts of hexamethylene diisocyanate or isophorone diisocyanate with monohydric or polyhydric alcohols, e.g. Methanol, ethanol, / so-propanol, n-propanol, n-butanol, / so-butanol, se / butanol, ferf-butanol, n-hexanol, n-heptanol, n-octanol, n-decanol, n-dodecanol (Lauryl alcohol), 2-ethylhexanol, n-pentanol, stearyl alcohol, cetyl alcohol, lauryl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 1, 3-propanediol monomethyl ether, cyclopentanol, cyclohexanol, cyclooctanol, cyclododecanol, or mixtures thereof can be obtained. These urethane and / or allophanate-containing polyisocyanates generally have an NCO content of 12 to 20 wt .-% and an average NCO functionality of 2.5 to 4.5. The polyisocyanates can be used in a mixture, if appropriate also in a mixture with diisocyanates.

To prepare the highly functional urethane group-containing polyisocyanates, polyisocyanate (B) and compound (A) are reacted with or without solvent under urethanization conditions.

"Urethanization conditions" means that the reaction conditions are selected so that at least partially urethane groups are formed by reaction of the isocyanate group-containing component (B) and the hydroxyl-containing component (A).

The temperature in this reaction is generally up to 150 ° C., preferably up to 120 ° C., more preferably below 100 ° C. and very particularly preferably below 90 ° C., and is usually carried out in the presence of at least one catalyst which contains the urethanization catalyzed reaction. The reaction can also be carried out in the absence of a catalyst. In general, the temperature of the reaction should be at least 20 ° C, preferably at least 30, more preferably at least 40 and most preferably at least 50 ° C.

Catalysts are in this case those compounds which, owing to their presence in a starting material mixture, lead to a higher proportion of urethane group-containing reaction products than the same starting material mixture in their absence under the same reaction conditions.

These are, for example, organic amines, in particular tertiary aliphatic, cycloaliphatic or aromatic amines, and / or Lewis-acidic organic metal compounds. As Lewis acidic organic metal compounds are e.g. Tin compounds, such as tin (II) salts of organic carboxylic acids, e.g. Tin (II) diacetate, stannous (II) dioctoate, stannous (II) bis (ethylhexanoate) and stannous (II) dilaurate and the dialkyltin (IV) salts of organic carboxylic acids, e.g. Dimethyltin diacetate, dibutyltin diacetate, dibutyltin dibutyrate, dibutyltin bis (2-ethylhexanoate), dibutyltin dilaurate, dibutyltin maleate, dioctyltin dilaurate and dioctyltin diacetate. In addition, zinc (II) salts can be used, such as zinc (II) dioctoate. Metal complexes such as acetylacetonates of iron, titanium, aluminum, zirconium, manganese, nickel, zinc and cobalt are also possible. Other metal catalysts are described by Blank et al. in Progress in Organic Coatings, 1999, Vol. 35, pages 19-29.

Preferred Lewis-acidic organic metal compounds are dimethyltin diacetate, dibutyltin dibutyrate, dibutyltin bis (2-ethylhexanoate), dibutyltin dilaurate, dioctyltin dilaurate, zinc (II) dioctoate, zirconium acetylacetonate and zirconium-2, 2,6,6-tetramethyl-3,5-heptanedionate. Also bismuth and cobalt catalysts and cesium salts can be used as catalysts. Suitable cesium salts are those compounds in which the following anions are used: F - C, CIO ^" , CIO ₃ -, CI0 ₄ -, Br, J, J0 ₃ -, CN, OCN, N0 ₂ -, N0 ₃ -, HC0 ₃ -, C0 ₃ 2-, S ² -, SH-, HSO ₃ -, S0 ₃ ^{2 "} , HS0 ₄ -, S0 ₄ ^2" , S ₂ 0 ₂ ² -, S ₂ 0 ₄ ² -, S ₂ 0 ₅ ² -, S ₂ 0 ₆ ² -, S ₂ 0 ₇ ^{2 "} , S ₂ 0 ₈ ² -, H ₂ P0 ₂ -, H ₂ P0 ₄ -, HP0 ₄ ² -, P0 ₄ ^{3 "} , P ₂ 0 ₇ ^4" , (OC _n H _{2n +} i) -, (C _n H _2n -i0 ₂ ) -, (C _n H _2n - ₃ 0 ₂ ) - and (C _{n +} iH _2n - ₂ 0 ₄ ) ² -, where n is the numbers 1 to 20.

Cesium carboxylates in which the anion is the formula are preferred

(C _n H _2n -i0 ₂ ) - as well as (C _n + iH _2n - ₂ 0 ₄ ) ² - with n equal to 1 to 20, obeys. Particularly preferred cesium salts have as anions monocarboxylates of the general formula

(C _n H _2n -i0 ₂ ) -, where n is the numbers 1 to 20. Particular mention should be made here of formate, acetate, propionate, hexanoate and 2-ethylhexanoate.

Furthermore, the following can be used as catalysts: Organic metal salts of the formula (A) _n -R-O-CO-O ^{e M®} according to US Pat. No. 3,817,939, in which

A is a hydroxyl group or a hydrogen atom, n is a number from 1 to 3,

 R is a polyfunctional linear or branched, aliphatic or aromatic hydrocarbon radical and

M ^® in cation, for example an alkali metal cation or a quaternary ammonium cation, such as tetraalkylammonium, and

 - Quaternary hydroxyalkylammonium compounds of the formula

R ²⁴ , R ²⁵ , R ²⁶ N ^® -CH ₂ -CH (OH) -R ^{27 ®} 0- (CO) -R ²⁸ as a catalyst according to DE-A-26 31 733 (US-A-4 040 992) the definitions given there for the radicals.

Quaternary ammonium salts are particularly suitable as catalysts for the process

With

^Y® = carboxylate (R ¹³ COO), fluoride (F), carbonate (R ¹³ O (CO) O) or hydroxide (OH), as for Y ^" = OH ^" in US Patent 4,324,879 and in German Offenlegungsschriften 2,806,731 and 2,901,479.

The radical ^Y.sup.- is preferably a carboxylate, carbonate or hydroxide and particularly preferably a carboxylate or hydroxide.

R ¹³ is hydrogen, C 1 to C 20 alkyl, CQ to C 12 -Al 1 or C ₇ to C 20 arylalkyl, each of which may optionally be substituted.

Preferably, R ^{13 is} hydrogen or C ¹ to C 6 alkyl.

Preferred quaternary ammonium salts are those in which the radicals R ⁹ to R ^{12 represent} identical or different alkyl groups having 1 to 20, preferably 1 to 4, carbon atoms, which are optionally substituted by hydroxyl or phenyl groups. Two of the radicals R ⁹ to R ¹² may also together with the nitrogen atom and optionally a further nitrogen or oxygen atom form a heterocyclic, five-, six- or seven-membered ring. The radicals R ⁹ to R ¹¹ may in any case also represent ethylene radicals which together with the quaternary nitrogen atom and another tertiary nitrogen atom form a bicyclic triethylenediamine structure, provided that the radical R ¹² then represents a hydroxyalkyl group having 2 to 4 carbon atoms, in which the hydro xyl group is preferably located in the 2-position to the quaternary nitrogen atom. The hydroxy-substituted radical or the hydroxy-substituted radicals may also contain other substituents, for example C 1 -C 4 -alkyloxy substituents. The ammonium ions may also be part of a mono- or poly-ring system, for example derived from piperazine, morpholine, piperidine, pyrrolidine, quinuclidine or di-azabicyclo [2.2.2] octane.

Examples of groups having from 1 to 20 carbon atoms R ⁹ to R ¹² are independently of one another methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl , 2,4,4-trimethylpentyl, nonyl, isononyl, decyl, dodecyl, tetradecyl, heptadyl, octadecyl, 1,1-dimethylpropyl, 1,1-dimethylbutyl, 1,1,3,3-tetramethylbutyl, benzyl , 1 - phenylethyl, 2-phenylethyl, α, α-dimethylbenzyl, benzhydryl, p-tolylmethyl, 1- (p-butylphenyl) ethyl, p-chlorobenzyl, 2,4-dichlorobenzyl, p-methoxybenzyl, m-ethoxybenzyl, 2 Cyanoethyl, 2-cyanopropyl, 2-methoxycarbonethyl, 2-ethoxycarbonylethyl, 2-butoxycarbonylpropyl, 1, 2-di- (methoxycarbonyl) -ethyl, 2-methoxyethyl, 2-ethoxyethyl, 2-butoxyethyl, diethoxymethyl, diethoxyethyl, chloromethyl, 2-chloroethyl, trichloromethyl, trifluoromethyl, 1,1-dimethyl-2-chloroethyl, 2-methoxyisopropyl, 2-ethoxyethyl, 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 4-hydroxybutyl, 6-hydroxyhexyl, 2-hydroxy 2,2-dimethy ethyl, 2-phenoxyethyl, 2-phenoxypropyl, 3-phenoxypropyl, 4-phenoxybutyl, 6-phenoxyhexyl, 2-methoxyethyl, 2-methoxypropyl, 3-methoxypropyl, 4-methoxybutyl, 6-methoxyhexyl, 2-ethoxyethyl, 2-ethoxypropyl, 3-ethoxypropyl, 4-ethoxybutyl, 6-ethoxyhexyl, phenyl, tolyl, xylyl, α-naphthyl, β-naphthyl, 4-diphenylyl, chlorophenyl, dichlorophenyl, trichlorophenyl, difluorophenyl, methylphenyl, dimethylphenyl, trimethylphenyl, ethylphenyl, diethylphenyl, etc -Propylphenyl, tert-butylphenyl, dodecylphenyl, methoxyphenyl, dimethoxyphenyl, methylnaphthyl, isopropylnaphthyl, chloronaphthyl, 2,6-dimethylphenyl, 2,4,6-trimethylphenyl, 2,6-dimethoxyphenyl, 2,6-dichlorophenyl, cyclopentyl, cyclohexyl , Cyclooctyl, cyclododecyl, methylcyclopentyl, dimethylcyclopentyl, methylcyclohexyl, dimethylcyclohexyl, diethylcyclohexyl, butylcyclohexyl, chlorocyclohexyl, dichlorocyclohexyl, dichlorocyclopentyl, norbornyl or norbornenyl.

Preferred are independently of one another the radicals R ⁹ to R ¹² Ci to C4-alkyl. R ¹² may additionally be benzyl or a remainder of the formula

R 'CH;

OH in which R ¹⁴ and R ¹⁵ independently of one another may be hydrogen or C 1 to C ₄ -alkyl.

Particularly preferred radicals R ⁹ to R ¹² are independently methyl, ethyl and n-butyl and for R ¹² additionally benzyl, 2-hydroxyethyl and 2-hydroxypropyl. The following catalysts may preferably be used for the process according to the invention:

Quaternary ammonium hydroxides, preferably N, N, N-trimethyl-N-benzylammonium hydroxide and N, N, N-trimethyl-N- (2-hydroxypropyl) -ammonium hydroxide, according to DE-A-38 06 276.

Hydroxyalkyl-substituted quaternary ammonium hydroxides according to EP-A-10 589 (US Pat. No. 4,324,879).

Organic metal salts of the formula No. 3,817,939, in which A, a hydroxyl group or a hydrogen atom, n is a number from 1 to 3, R is a polyfunctional linear or branched, aliphatic or aromatic hydrocarbon radical and M is a cation of a strong base, for example an alkali metal cation or a quaternary ammonium cation, such as tetraalkylammonium.

Preferred catalysts are zinc (II) salts, among them especially zinc acetylacetonate.

Also preferred is dibutyltin dilaurate.

Depending on the activity, the catalyst is normally used in amounts of from 0.001 to 10 mol% with respect to isocyanate groups used, preferably from 0.5 to 8, more preferably from 1 to 7 and very particularly preferably from 2 to 5 mol%. The polyisocyanate (B) is used in at least a threefold excess of the NCO groups based on the hydroxy groups in the compound (A), preferably in an at least 4-fold excess, more preferably at least 5 and most preferably at least 6-fold Excess. The unreacted portion of polyisocyanate (B) can either be separated or preferably remain in the reaction mixture.

The reaction is preferably carried out without solvent, but can also be carried out in the presence of at least one solvent. Likewise, the reaction mixture obtained can be formulated in a solvent after completion of the reaction.

Suitable solvents are those which have no isocyanate-reactive groups and in which the polyisocyanates at least 10% by weight, preferably at least 25, more preferably at least 50, most preferably at least 75, in particular at least 90 and especially are soluble to at least 95% by weight. Examples of such solvents are aromatic (including alkylated benzenes and naphthalenes) and / or (cyclo) aliphatic hydrocarbons and mixtures thereof, chlorinated hydrocarbons, ketones, esters, alkoxylated Alkansäurealkylester, ethers, respectively mixtures of solvents.

Preferred aromatic hydrocarbon mixtures are those which comprise predominantly aromatic C ₇ - to C ₄ -hydrocarbons and may have a boiling range of from 10 to 300 ° C., particular preference is given to toluene, o-, m- or p-xylene, trimethylbenzene isomers, tetramethylbenzene isomers, Ethylbenzene, cumene, tetrahydronaphthalene and mixtures containing such.

Examples of these are the Solvesso® grades from ExxonMobil Chemical, in particular Solvesso® 100 (CAS No. 64742-95-6, predominantly Cg and Cio-aromatics, boiling range about 154-178 ° C.), 150 (boiling range approx 182-207 ° C) and 200

(CAS No. 64742-94-5), as well as Shell's Shellsol® brands, Caromax® (e.g., Caromax® 18) from Petrochem Carless, and Hydrosol from DHC (e.g., as Hydrosol® A 170). Hydrocarbon mixtures of paraffins, cycloparaffins and aromatics are also known under the designations crystal oil (for example crystal oil 30, boiling range about 158-198 ° C. or crystal oil 60: CAS No. 64742-82-1), white spirit (for example likewise CAS No. 64742). 82-1) or solvent naphtha (light: boiling range about 155-180 ° C, heavy: boiling range about 225-300 ° C) commercially available. The aromatic content of such hydrocarbon mixtures is generally more than 90% by weight, preferably more than 95, more preferably more than 98, and very preferably more than 99% by weight. It may be useful to use hydrocarbon mixtures with a particularly reduced content of naphthalene.

(Cyclo) aliphatic hydrocarbons are, for example, decalin, alkylated decalin and isomer mixtures of straight-chain or branched alkanes and / or cycloalkanes. The content of aliphatic hydrocarbons is generally less than 5, preferably less than 2.5 and more preferably less than 1% by weight.

Examples of esters are n-butyl acetate, ethyl acetate, 1-methoxypropyl acetate-2 and 2-methoxyethyl acetate.

Ethers are, for example, tetrahydrofuran (THF), dioxane and the dimethyl, ethyl or n-butyl ethers of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol or tripropylene glycol.

Examples of ketones are acetone, diethyl ketone, ethyl methyl ketone, isobutyl methyl ketone, methyl amyl ketone and tert-butyl methyl ketone. It is a preferred embodiment of the present invention to formulate the high-functionality polyisocyanates according to the invention with a solvent. A preferred solvent is n-butyl acetate. The concentration of the polyisocyanate according to the invention in the solution should be at least 50% by weight, preferably at least 60% by weight and more preferably at least 70% by weight.

The urethane-containing high-functionality polyisocyanates according to the invention generally have an NCO functionality of more than 2, preferably at least 3, more preferably at least 4, very preferably at least 5 and in particular more than 6.

The urethane-containing high-functionality polyisocyanate according to the invention generally have a number-average molecular weight Mn of from 1,000 to 20,000, preferably from 1,200 to 10,000 and more preferably from 1,500 to 5,000 g / mol and a weight-average molecular weight Mw of from 1,000 to 50,000 and preferably from 1,500 to 30,000. The molecular weights can be determined by gel permeation chromatography with a suitable polymer standard and tetrahydrofuran or dimethylformamide as eluent. The high-functionality urethane group-containing polyisocyanates according to the invention are used, for example, in two-component polyurethane coatings containing at least one component which contain at least two isocyanate-reactive groups (binders). For this purpose, the high-functionality urethane group-containing polyisocyanates according to the invention can be used alone or in admixture with other polyisocyanates (C) as crosslinking component.

Such other polyisocyanates (C) are obtainable by oligomerization of monomeric isocyanates. The monomeric isocyanates used for this purpose can be aromatic, aliphatic or cycloaliphatic, preferably aliphatic or cycloaliphatic, which in this document is referred to briefly as (cyclo) aliphatic, particularly preferred are aliphatic isocyanates.

Aromatic isocyanates are those which contain at least one aromatic ring system, ie both purely aromatic and also araliphatic compounds.

Cycloaliphatic isocyanates are those which contain at least one cycloaliphatic ring system. Aliphatic isocyanates are those which contain exclusively straight or branched chains, ie acyclic compounds. The monomeric isocyanates are preferably diisocyanates which carry exactly two isocyanate groups. In principle, however, it may also be monoisocyanates with an isocyanate group. In principle, higher isocyanates having an average of more than 2 isocyanate groups are also considered. Triisocyanates such as triisocyanatononane, 2,4,6-triisocyanatotoluene, triphenylmethane triisocyanate or 2,4,4'-triisocyanatodiphenyl ether or the mixtures of di-, tri- and higher polyisocyanates suitable for example by phosgenation of corresponding aniline / formaldehyde are suitable for this purpose Condensates are obtained and represent methylene bridged polyphenyl polyisocyanates.

These monomeric isocyanates have no significant reaction products of the isocyanate groups with itself. The monomeric isocyanates are preferably isocyanates having 4 to 20 carbon atoms. Examples of customary diisocyanates are aliphatic diisocyanates such as tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, hexamethylene diisocyanate (1,6-diisocyanatohexane), octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate, derivatives of lysine diisocyanate, trimethylhexane diisocyanate or tetra methylhexane diisocyanate, cycloaliphatic diisocyanates such as 1, 4, 1, 3 or 1, 2

Diisocyanatocyclohexane, 4,4'- or 2,4'-di (isocyanatocyclohexyl) methane, 1-isocyanato-3,3,5-trimethyl-5- (isocyanatomethyl) cyclohexane (isophorone diisocyanate), 1, 3 or 1, 4 Bis (isocyanatomethyl) cyclohexane or 2,4- or 2,6-diisocyanato-1-methylcyclohexane and also 3 (or 4), 8 (or 9) -bis (isocyanatomethyl) -tricyclo [5.2.1.0 ^{2 6} ] decane -lsomerengemische, and aromatic diisocyanates such as 2,4- or 2,6-toluene diisocyanate and their isomer mixtures, m- or p-xylylene diisocyanate, 2,4'- or 4,4'-diisocyanatodiphenylmethane and their isomer mixtures, 1, 3 or 1 , 4-phenylenediisocyanate, 1-chloro-2,4-phenylenediisocyanate, 1,5-naphthylenediisocyanate, diphenyl-4,4'-diisocyanate, 4,4'-diisocyanato-3,3'-dimethyldiphenyl, 3-methyldi-phenylmethane 4,4'-diisocyanate, tetramethylxylylene diisocyanate, 1,4-diisocyanatobenzene or diphenyl ether-4,4'-diisocyanate.

Particularly preferred are 1, 6-hexamethylene diisocyanate, 1, 3-bis (isocyanatomethyl) cyclohexane, isophorone diisocyanate and 4,4'- or 2,4'-di (isocyanatocyclohexyl) methane, most preferably isophorone diisocyanate and 1, 6- Hexamethylene diisocyanate, particularly preferred is 1, 6-hexamethylene diisocyanate.

There may also be mixtures of said isocyanates.

Isophorone diisocyanate is usually present as a mixture, namely of the cis and trans isomers, generally in the ratio of about 60:40 to 80:20 (w / w), preferably in the ratio of about 70:30 to 75 : 25 and most preferably in the ratio of about 75:25. Dicyclohexylmethane-4,4'-diisocyanate may also be present as a mixture of the different cis and trans isomers.

It is possible to use both those diisocyanates which are obtained by phosgenation of the corresponding amines and those which, without the use of phosgene, ie. H. after phosgene-free process, are produced. According to EP-A-0 126 299 (US Pat. No. 4,596,678), EP-A-126 300 (US Pat. No. 4,596,679) and EP-A-355 443 (US Pat. No. 5,087,739), for example, (cyclo) aliphatic diisocyanates, eg such as 1, 6-hexamethylene diisocyanate (HDI), isomeric aliphatic diisocyanates having 6 carbon atoms in the alkylene radical, 4,4'- or 2,4'-di (isocyanatocyclohexyl) methane and 1-isocyanato-3-isocyanato-methyl-3,5, 5-trimethylcyclohexane (isophorone diisocyanate or IPDI) are prepared by reacting the (cyclo) aliphatic diamines with, for example, urea and alcohols to give (cyclo) aliphatic biscarbamic esters and their thermal cleavage into the corresponding diisocyanates and alcohols. The synthesis is usually carried out continuously in a cyclic process and, if appropriate, in the presence of N-unsubstituted carbamic acid esters, dialkyl carbonates and other by-products recycled from the reaction process. Thus obtained diisocyanates generally have a very low or even non-measurable proportion of chlorinated compounds, which is advantageous, for example, in applications in the electronics industry. In one embodiment, the isocyanates used have a total content of hydrolyzable chlorine of less than 200 ppm, preferably less than 120 ppm, more preferably less than 80 ppm, even more preferably less than 50 ppm, in particular less than 15 ppm and especially less than 10 ppm. This can be measured, for example, by ASTM D4663-98. Of course, it is also possible to use monomeric isocyanates having a higher chlorine content, for example up to 500 ppm.

Of course, mixtures of such monomeric isocyanates, which have been obtained by reacting the (cyclo) aliphatic diamines with, for example, urea and alcohols and cleavage of the resulting (cyclo) aliphatic biscarbamic acid esters, with such diisocyanates, which have been obtained by phosgenation of the corresponding amines, be used.

The polyisocyanates (C) to which the monomeric isocyanates can be oligomerized are generally characterized as follows:

The average NCO functionality of such compounds is generally at least 1.8, and may be up to 8, preferably 2 to 5 and more preferably 2.4 to 4.

The content of isocyanate groups after the oligomerization, calculated as NCO = 42 g / mol, is, unless stated otherwise, usually from 5 to 25% by weight.

The polyisocyanates (C) are preferably the following compounds: Isocyanurate group-containing polyisocyanates of aromatic, aliphatic and / or cycloaliphatic diisocyanates. Particular preference is given here to the corresponding aliphatic and / or cycloaliphatic isocyanato-isocyanurates and in particular those based on hexamethylene diisocyanate and isophorone diisocyanate. The isocyanurates present are in particular tris-isocyanatoalkyl or tris-isocyanatocycloalkyl isocyanurates, which are cyclic trimers of the diisocyanates, or mixtures with their higher homologs containing more than one isocyanurate ring. The isocyanato-isocyanurates generally have an NCO content of 10 to 30 wt .-%, in particular 15 to 25 wt .-% and an average NCO functionality of 2.6 to 8.

Uretdione group-containing polyisocyanates having aromatically, aliphatically and / or cyclo-aliphatically bonded isocyanate groups, preferably aliphatically and / or cycloaliphatically bonded and in particular those derived from hexamethylene diisocyanate or isophorone diisocyanate. Uretdione diisocyanates are cyclic dimerization products of diisocyanates.

 The polyisocyanates containing uretdione groups are obtained in the context of this invention in a mixture with other polyisocyanates, in particular those mentioned under 1). For this purpose, the diisocyanates can be reacted under reaction conditions under which both uretdione groups and the other polyisocyanates are formed, or first the uretdione groups formed and these are then reacted to the other polyisocyanates or the diisocyanates first to the other polyisocyanates and these then to uretdione groups-containing Products are implemented.

Biuret group-containing polyisocyanates with aromatic, cycloaliphatic or aliphatic bound, preferably cycloaliphatic or aliphatic bound isocyanate groups, in particular tris (6-isocyanatohexyl) biuret or mixtures thereof with its higher homologs. These biuret polyisocyanates generally have an NCO content of 18 to 22 wt .-% and an average NCO functionality of 2.8 to 6 on.

Urethane and / or allophanate groups containing polyisocyanates having aromatically, a-aliphatically or cycloaliphatically bonded, preferably aliphatically or cycloaliphatically bonded isocyanate groups, as for example by reacting excess amounts of diisocyanate, for example hexamethylene diisocyanate or isophorone diisocyanate, with mono- or polyhydric alcohols. These urethane and / or allophanate-containing polyisocyanates generally have an NCO content of 12 to 24 wt .-% and an average NCO functionality of 2.5 to 4.5. Such urethane and / or allophanate groups containing polyisocyanates can uncatalyzed or preferably in the presence of catalysts such as ammonium carboxylates or Hydroxides, or Allophanatisierungskatalysatoren, eg Zn (II) compounds, each in the presence of mono-, di- or polyhydric, preferably monohydric alcohols produced.

Oxadiazintriongruppen containing polyisocyanates, preferably derived from hexamethylene diisocyanate or isophorone diisocyanate. Such oxadiazinetrione-containing polyisocyanates are accessible from diisocyanate and carbon dioxide.

Iminooxadiazindiongruppen containing polyisocyanates, preferably derived from hexamethylene diisocyanate or isophorone diisocyanate. Such iminooxadiazine-dione-containing polyisocyanates can be prepared from diisocyanates by means of special catalysts.

7) Uretonimine-modified polyisocyanates.

8) carbodiimide-modified polyisocyanates.

9) Hyperbranched polyisocyanates, as are known, for example, from DE-A1 10013186 or DE-A1 10013187.

10) polyurethane-polyisocyanate prepolymers of di- and / or polyisocyanates with alcohols.

1 1) polyurea-polyisocyanate prepolymers. 12) The polyisocyanates 1) -1 1), preferably 1), 3), 4) and 6) may after their preparation in biuret or urethane / allophanate groups having polyisocyanates having aromatic, cycloaliphatic or aliphatic bound, preferably (cyclo ) aliphatically bound isocyanate groups. The formation of biuret groups takes place, for example, by addition of water or reaction with amines. The formation of urethane and / or allophanate groups by reaction with mono-, di- or polyhydric, preferably monohydric alcohols, optionally in the presence of suitable catalysts. These biuret or urethane / allophanate groups containing polyisocyanates generally have an NCO content of 18 to 22 wt .-% and an average NCO functionality of 2.8 to 6 on.

13) Hydrophilically modified polyisocyanates, ie polyisocyanates which, in addition to the groups described under 1 -12, contain those which formally arise by adding molecules having NCO-reactive groups and hydrophilizing groups to the isocyanate groups of the above molecules. The latter are nonionic groups such as alkyl polyethylene oxide and / or ionic, which are derived from phosphoric acid, phosphonic acid, sulfuric acid or sulfonic acid, or their salts. 14) Modified polyisocyanates for dual-cure applications, ie polyisocyanates which contain, in addition to the groups described under 1-12, those which formally form by addition of molecules with NCO-reactive groups and UV- or actinic radiation-crosslinkable groups to the isocyanate groups of the above molecules , These molecules are, for example, hydroxyalkyl (meth) acrylates and other hydroxyl groups.

Vinyl compounds.

The diisocyanates or polyisocyanates listed above may also be present at least partially in blocked form.

Linking classes of compounds are described in D.A. Wieks, Z.W. Wieks, Progress in Organic Coatings, 36, 148-172 (1999), 41, 1-83 (2001) and 43, 131-140 (2001).

Examples of classes of compounds used for blocking are phenols, imidazoles, triazoles, pyrazoles, oximes, N-hydroxyimides, hydroxybenzoic acid esters, secondary amines, lactams, CH-acidic cyclic ketones, malonic esters or alkyl acetoacetates.

In a preferred embodiment of the present invention, the polyisocyanate (C) is selected from the group consisting of isocyanurates, biurets, urethanes and allophanates, preferably from the group consisting of isocyanurates, urethanes and allophanates, particularly preferably from the group consisting of isocyanurates and allophanates, in particular is an isocyanurate group-containing polyisocyanate.

In a particularly preferred embodiment, the polyisocyanate (C) is isocyanurate group-containing polyisocyanates of 1,6-hexamethylene diisocyanate.

In a further particularly preferred embodiment, the polyisocyanate is a mixture of isocyanurate-containing polyisocyanates of 1,6-hexamethylene diisocyanate and of isophorone diisocyanate.

In a particularly preferred embodiment, the polyisocyanate (C) is a mixture comprising low-viscosity polyisocyanates, preferably polyisocyanates containing isocyanurate groups, having a viscosity of 600-1500 mPa * s, in particular less than 1200 mPa * s, low-viscosity urethanes and / or allophanates having a viscosity of 200-1600 mPa * s, in particular 600-1500 mPa * s, and / or iminooxadiazinedione-containing polyisocyanates.

In this document, the viscosity at 23 ° C according to DIN EN ISO 3219 / A.3 is given in a cone-plate system with a rate gradient of 1000 s ¹ , unless otherwise noted. The high-functionality urethane group-containing polyisocyanates according to the invention may optionally be used in admixture with other polyisocyanates (C) as crosslinker components with at least one binder in polyurethane coatings. As a rule, for polyisocyanate compositions, ie the sum of the isocyanate-containing compounds,

50 to 100% by weight of the highly functional urethane group-containing polyisocyanates according to the invention, preferably 50 to 90% by weight and more preferably 60 to 80% by weight, and 0 to 50% by weight of other polyisocyanates (C), preferably 10 to 50, particularly preferably 20 to 40% by weight %, with the proviso that the sum is always 100% by weight. The binders may be, for example, polyacrylate polyols, polyester polyols, polyether polyols, polyurethane polyols; polyurea; Polyesterpolyacrylatpolyole; Polyester polyurethane polyols; Polyurethane polyacrylate polyols, polyurethane modified alkyd resins; Fatty acid-modified polyester polyurethane polyols, copolymers with allyl ethers, graft polymers of the substance groups mentioned with e.g. different Glasübergangstempera- ren, and mixtures of said binders act. Preference is given to polyacrylate polyols, polyester polyols and polyether polyols.

Preferred OH numbers, measured according to DIN 53240-2, are 40-350 mg KOH / g solid resin for polyester, preferably 80-180 mg KOH / g solid resin, and 15-250 mg KOH / g solid resin for polyacrylate, preferably 80 -160 mg KOH / g.

In addition, the binders may have an acid number according to DIN EN ISO 3682 up to 200 mg KOH / g, preferably up to 150 and particularly preferably up to 100 mg KOH / g. Polyacrylate polyols preferably have a molecular weight M _n of at least 1000, particularly preferably at least 2000 and very particularly preferably at least 5000 g / mol. The molecular weight M _n may in principle be unlimited upwards, preferably up to 200,000, particularly preferably up to 100,000, very particularly preferably up to 80,000 and in particular up to 50,000 g / mol.

The latter can be, for example, monoesters of α, β-unsaturated carboxylic acids, such as acrylic acid, methacrylic acid (referred to in this document as "(meth) acrylic acid"), with di- or polyols, which preferably have 2 to 20 C atoms and have at least two hydroxyl groups, such as ethylene glycol, diethylene glycol, triethylene glycol, 1, 2-propylene glycol, 1, 3-propylene glycol, 1, 1 - dimethyl-1, 2-ethanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, tripropylene glycol, 1, 4-butanediol, 1,5-pentanediol, neopentyl glycol, hydroxypivalic acid neopentyl glycol ester, 2-ethyl-1,3-propanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3 Propanediol, 1,6-hexanediol, 2-methyl-1,5-pentanediol, 2-ethyl-1,4-butanediol, 2-ethyl-1,3-hexanediol, 2,4-diethyl-octane-1,3 diol, 2,2-bis (4-hydroxycyclohexyl) propane, 1, 1, 1, 2, 1, 3- and 1, 4-bis (hydroxymethyl) cyclohexane, 1, 2, 1, 3 or 1,4-cyclohexanediol, glycerol, trimethylolethane, trimethylolpropane, trimethylolbutane, pentaerythritol, ditrimethylolpropane, dipentaerythritol, sorbitol, mannitol, diglycerol, threitol, erythritol, adonite (ribitol), arabitol (lyxite), xylitol, dulcitol (galactitol), maltitol , Isomalt, poly-THF having a molecular weight between 162 and 4500, preferably 250 to 2000, poly-1,3-propanediol or polypropylene glycol having a molecular weight between 134 and 2000 or polyethylene glycol having a molecular weight between 238 and 2000. Preference is given to 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2 or 3

Hydroxypropyl acrylate, 1,4-butanediol monoacrylate or 3- (acryloyloxy) -2-hydroxypropyl acrylate and more preferably 2-hydroxyethyl acrylate and / or 2-hydroxyethyl methacrylate.

The hydroxyl-containing monomers are used in the copolymerization in admixture with other polymerizable, preferably free-radically polymerizable monomers, preferably those which contain more than 50% by weight of C 1 -C 20, preferably C 1 -C ₄ -alkyl (meth) acrylate , (Meth) acrylic acid, vinylaromatics having up to 20 carbon atoms, vinyl esters of carboxylic acids containing up to 20 carbon atoms, vinyl halides, non-aromatic hydrocarbons having 4 to 8 carbon atoms and 1 or 2 double bonds, unsaturated nitriles and mixtures thereof , Particular preference is given to the polymers which consist of more than 60% by weight of C 1 -C 10 -alkyl (meth) acrylates, styrene and derivatives thereof, vinylimidazole or mixtures thereof.

In addition, the polymers may contain hydroxy-functional monomers corresponding to the above hydroxy group content and optionally further monomers, e.g.

 (Meth) acrylic acid glycidyl epoxyesters, ethylenically unsaturated acids, in particular carboxylic acids, acid anhydrides or acid amides.

Other polymers are e.g. Polyesterols, as obtainable by condensation of polycarboxylic acids, in particular dicarboxylic acids with polyols, in particular diols. In order to ensure a functionality of the polyester polyol which is suitable for the polymerization, triols, tetrols, etc., as well as triacids, etc. are also used in some cases.

Polyesterpolyols are known, for example, from Ullmanns Encyklopadie der technischen Chemie, 4th Edition, Volume 19, pages 62 to 65. Preference is given to using polyesterpolyols which are obtained by reacting dihydric alcohols with dibasic carboxylic acids. Instead of the free polycarboxylic acids, it is also possible to use the corresponding polycarboxylic acid anhydrides or corresponding polycarboxylic acid esters of lower alcohols or mixtures thereof to prepare the polyesterpolyols. The polycarboxylic acids may be aliphatic, cycloaliphatic, aromatic or heterocyclic and may optionally be substituted, for example by halogen atoms, and / or unsaturated. Examples include: Oxalic acid, maleic acid, fumaric acid, succinic acid, glutaric acid, adipic acid, sebacic acid, dodecanedioic acid, o-phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, azelaic acid, 1,4-cyclohexanedicarboxylic acid or tetrahydrophthalic acid, suberic acid, azelaic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrachlorophthalic anhydride, Endomethylenetetrahydrophthalic anhydride, glutaric anhydride, maleic anhydride, dimer fatty acids, their isomers and hydrogenation products as well as ves resterable derivatives such as anhydrides or dialkyl esters, for example Ci-C4-alkyl esters, preferably methyl, ethyl or n-butyl esters, of the acids mentioned are used. Preference is given to dicarboxylic acids of the general formula HOOC- (CH 2) _y -COOH, where y is a number from 1 to 20, preferably an even number from 2 to 20, particularly preferably succinic acid, adipic acid, sebacic acid and dodecanedicarboxylic acid.

Suitable polyhydric alcohols for preparing the polyesterols are 1, 2-propanediol, ethylene glycol, 2,2-dimethyl-1,2-ethanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1, 4-butanediol, 3-methylpentane-1, 5-diol, 2-ethylhexane-1,3-diol, 2,4-diethyloctane-1,3-diol, 1,6-hexanediol, poly-THF having a molecular weight between 162 and 4500, preferably 250 to 2000, poly-1,3-propanediol having a molecular weight between 134 and 1 178, poly-1,2-propanediol having a molecular weight between 134 and 898, polyethylene glycol having a molecular weight between 106 and 458, Neopentyl glycol, hydroxypivalic acid neopentyl glycol ester, 2-ethyl-1,3-propanediol, 2-methyl-1,3-propanediol, 2,2-bis (4-hydroxycyclohexyl) propane, 1, 1, 1, 2, 1, 3 and 1, 4-cyclohexanedimethanol, 1, 2-, 1, 3- or 1, 4-cyclohexanediol, trimethylolbutane, trimethylolpropane, trimethylolethane, neopentyl glycol, pentaerythritol, glycerol, ditrimethylolpropane, dipentaeythritol, sorbitol, mannitol, diglycerol, Threit , Erythritol, adonite (ribitol), Arabitol (lyxite), xylitol, dulcitol (galactitol), maltitol or isomalt, which may optionally be alkoxylated as described above.

Alcohols of the general formula HO- (CH 2) _x -OH, where x is a number from 1 to 20, preferably an even number from 2 to 20, are preferred. Preferred are ethylene glycol, butane-1, 4-diol, hexane-1, 6-diol, octane-1, 8-diol and dodecane-1, 12-diol. Further preferred is neopentyl glycol. Also suitable are polycarbonate diols, as can be obtained, for example, by reacting phosgene with an excess of the low molecular weight alcohols mentioned as synthesis components for the polyester polyols.

Also suitable are lactone-based polyesterdiols, which are homopolymers or mixed polymers of lactones, preferably terminal hydroxyl-containing addition products of lactones onto suitable difunctional starter molecules. Preferred lactones are those which are derived from compounds of the general formula HO- (CH 2) z -COOH, where z is a number from 1 to 20 and an H atom of a methylene unit is also denoted by a d- to C ₄ - Alkyl radical may be substituted. Examples are ε-caprolactone, β-propiolactone, gamma-butyrolactone and / or methyl-ε-caprolactone, 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid or pivalolactone, and mixtures thereof. Suitable starter components are, for example, those mentioned above as constituent components for the polyesterpolyols. dermolekularen dihydric alcohols. The corresponding polymers of ε-caprolactone are particularly preferred. Lower polyester diols or polyether diols can also be used as starters for the preparation of the lactone polymers. Instead of the polymers of lactones, it is also possible to use the corresponding, chemically equivalent polycondensates of the hydroxycarboxylic acids corresponding to the lactones.

Also suitable as polymers are polyetherols which are prepared by addition of ethylene oxide, propylene oxide or butylene oxide to H-active components. Likewise, polycondensates of butanediol are suitable.

Furthermore, it is possible to use hydroxy-functional carboxylic acids, for example dimethylolpropionic acid or dimethylolbutanoic acid.

The polymers may of course also be compounds with primary secondary amino groups.

Polyisocyanate composition and binder are prepared in a molar ratio of isocyanate groups to isocyanate-reactive groups of 0.1: 1 to 10: 1, preferably 0.2: 1 to 5: 1, particularly preferably 0.3: 1 to 3, for the preparation of the polyurethane coatings. 1, very particularly preferably 0.5: 1 to 2: 1, in particular 0.8: 1 to 1, 2: 1 and especially 0.9: 1 to 1, 1: 1 mixed together, where appropriate, further typical of the paint Components can be mixed and applied to the substrate.

Subsequently, the paint mixture is cured under suitable conditions. Depending on the application, this can be done, for example, at 100 to 140 ° C, for example, in paints in OEM applications, or in a lower temperature range of, for example, 20 to 80 ° C.

Depending on the temperature, this usually requires no more than 12 hours, preferably up to 8 hours, more preferably up to 6, very preferably up to 4 and in particular up to 3 hours.

Furthermore, coating compositions may contain 0 to 10% by weight of at least one UV stabilizer.

Suitable stabilizers include typical UV absorbers such as oxanilides, triazines and benzotriazole (the latter being available as Tinuvin® grades from Ciba Specialty Chemicals) and benzophenones. These may additionally 0 to 5% by weight of suitable radical scavengers, for example sterically hindered amines such as 2,2,6,6-tetramethylpiperidine, 2,6-di-tert-butylpiperidine or derivatives thereof, for. B. bis (2,2,6,6-tetra-methyl-4-piperidyl) sebacinate included. Furthermore, coating compositions may furthermore contain 0 to 10% by weight of further typical coatings additives. As further paint typical additives, for example, antioxidants, activators (accelerators), fillers, pigments, dyes, antistatic agents, flame retardants, thickeners, thixotropic agents, surface-active agents, viscosity modifiers, plasticizers or chelating agents can be used. Suitable thickeners besides free-radically (co) polymerized (co) polymers, customary organic and inorganic thickeners such as hydroxymethylcellulose or bentonite.

As chelating agents, e.g. Ethylenediamine and their salts and ß-diketones are used.

Suitable fillers include silicates, e.g. For example, by hydrolysis of silicon tetrachloride available silicates such as Aerosil® the Fa. Degussa, silica, talc, aluminum silicates, magnesium silicates, calcium carbonate, etc. The substrates are coated by conventional methods known in the art, wherein at least one coating composition on the substrate to be coated in the desired strength and the optional volatile constituents of the coating composition, optionally with heating, removed. If desired, this process can be repeated one or more times. The application to the substrate can in a known manner, for. Example by spraying, filling, doctoring, brushing, rolling, rolling, pouring, laminating, injection molding or coextrusion.

The thickness of such a layer to be hardened may be from 0.1 μm to several mm, preferably from 1 to 2000 μm, more preferably from 5 to 200 μm, very particularly preferably from 5 to 60 μm (based on the paint in the state in which Solvent is removed from the paint).

Furthermore, substrates coated with a lacquer containing the urethane-containing polyisocyanates according to the invention are also an object of the present invention.

Particularly suitable are such polyurethane coatings for applications in which a particularly high application safety, outdoor weather resistance, appearance, solvent, chemical and water resistance are required. The resulting two-component coating compositions and paint formulations are suitable in principle for coating substrates such as wood, wood veneer, paper, cardboard, textile, film, leather, fleece, plastic surfaces, glass, ceramics, mineral building materials, such as ment-shaped blocks and fiber cement boards or metals, which may be optionally pre-coated or pretreated. However, they are particularly preferably suitable for coating plastic surfaces and metallic substrates. These coating compositions are preferably used as clearcoats, basecoats and topcoats, primers and fillers; they are particularly suitable as a topcoat, preferably as a clearcoat, owing to their high scratch resistance, in particular in coatings on (large) vehicles and aircraft and in automotive coatings as an OEM and refinish application. It is an advantage of the urethane group-containing polyisocyanates according to the invention that they give high scratch resistance and clear elasticity in clearcoats. In addition, the products of the invention usually give a lower viscosity.

Examples:

Polyisocyanate A:

 Basonat® HI 100 from BASF SE, HDI isocyanurate with an NCO content of 22.2% and a viscosity of 3500 mPa * s at 23 ° C, functionality of about 3.4. Hazen color number:

 Method for determining the yellowing of technical fluids according to DIN ISO 6271. As standard, an acidic solution of potassium hexachloroplatinate is used.

Comparative Example 1

Basonat® Hl 100 from BASF SE: HDI isocyanurate with an NCO content of 22.2% and a viscosity of 2800 mPa * s at 23 ° C.

Comparative Example 2:

 Desmodur® N3790 from Bayer AG: HDI isocyanurate (90% in butyl acetate) with an NCO content of 17.8% and a viscosity of 2150 mPa * s at 23 ° C.

Example 1 :

 300.00 g (0.524 mol) of polyisocyanate A and 13.00 g (0.087 mol) of triethanolamine in 134.1 g of butyl acetate were mixed. The solution was biphasic at room temperature and had an NCO content of 15.0%. The solution became homogeneous after increasing the temperature of

Room temperature to 60 ° C. The mixture was reacted with the addition of dibutyltin dilaurate catalyst. After 1 hour at 60 ° C, the NCO content was 12.1%. The approach then became cooled and filtered through Seitz filter T5500. The corresponding product had a viscosity of 440 mPas at 23 ° C and a color number of 21 Hazen.

Example 2:

360.99 g (0.630 mol) of polyisocyanate A and 10.43 g (0.070 mol) of triethanolamine in 159.2 g of butyl acetate were mixed. The solution was biphasic at room temperature and had an NCO content of 14.5%. The solution was homogeneous after raising the temperature from room temperature to 60 ° C. The mixture was reacted with the addition of dibutyltin dilaurate catalyst. After 1.5 hours at 60 ° C., the NCO content was 12.2%. The reaction was then cooled and filtered through Seitz T5500 filter. The corresponding product had a viscosity of 320 mPas at 23 ° C and a color number of 23 Hazen.

Example 3:

 343.80 g (0.600 mol) of polyisocyanate A and 7.45 g (0.050 mol) of triethanolamine in 150.54 g of butyl acetate were mixed. The solution was biphasic at room temperature and had an NCO content of 15.5%. The solution became homogeneous as the temperature rose from room temperature to 60 ° C. The mixture was reacted with the addition of dibutyltin dilaurate catalyst. After 3 hours at 60 ° C, the NCO content was 13.5%. The reaction was then cooled and filtered through Seitz T5500 filter. The corresponding product had a viscosity of 120 mPas at 23 ° C. and a color number of 21 Hazen.

Example 4:

 343.80 g (0.600 mol) of polyisocyanate A were mixed in 153.5 g of butyl acetate and 5.40 g of 1,4-butanediol (0.060 mol) and 8.94 g (0.060 mol) of triethanolamine were added. The solution was cloudy at room temperature and had an NCO content of 14.8%. The solution became transparent after raising the temperature from room temperature to 60 ° C. The mixture was reacted with the addition of dibutyltin dilaurate catalyst. After 2.5 hours at 60 ° C, the NCO content was 1 1, 8%. The reaction was then cooled and filtered through Seitz T5500 filter. The corresponding product had a viscosity of 370 mPas at 23 ° C and a color number of 28 Hazen.

Application testing:

The inventive and comparative polyisocyanates were reacted with acrylic acid-free, hydroxy-functional polyacrylate polyols (Joncryl® 922, BASF, solid content = 80% in butyl acetate, OH number = 143 mg KOH / g corresponding to a stoichiometric NCO / OH ratio of 1: 1 mixed with butyl acetate to an application viscosity of 20 s (DIN 53 21 1, beaker 4 mm outlet nozzle). film thickness of 200 μιη applied to metal sheets. The clearcoats thus contained were cured after 10 minutes of aeration time at room temperature or for the determination of scratch resistance and acid resistance at 60 ° C. over a period of 30 minutes. Before the tests, the paint films were stored for 24 h at 23 ± 2 ° C and 50 ± 10% humidity.

Test methods:

 The gel time is considered to be the time between paint formulation and complete gelation of the paint.

 To determine the drying speed of the paint surface, the paint was touched after application at regular intervals with a cotton ball. The test is terminated as soon as cotton fibers no longer adhere to the paint surface.

The pendulum hardness was determined to König (EN ISO 1522). The cross hatch was determined according to EN ISO 2409. The marks are between 0 (very good adhesion) and 5 (very bad adhesion).

To determine the scratch resistance of the paint, the surface is scratched with a corundum particle-containing abrasive fleece under a weight of 500 g. The damage is determined by the gloss value of the paint. The reflow is determined by annealing at the temperature indicated in the table for the period specified in the table after scratching over 50 double strokes.

The sulfuric acid resistance (ethene test) was tested according to EN ISO 2812-1 (method 3) in the temperature range of 35-75 ° C:

Using a pipette, a 25 μΓΤΐ drop of 1% sulfuric acid was added to a cured coating at a given temperature (30 minutes at 80 or 130 ° C) on a gradient oven tray and heated in the gradient oven at 35-75 ° C for 30 minutes. The sheet was then washed off with water and dried. Indicated is the lowest temperature at which it was apparent that there was an etching on the paint.

With 80 ° C or 130 ° C in the table, the temperature of the curing of the paint is designated. nb stands for non-specific measured values.

Claims

claims

Highly functional urethane group-containing polyisocyanates obtainable by

 - Implementation of at least one tertiary di- or Trialkanolamins (A) with

 at least one polyisocyanate (B) having a functionality of more than 2, which has at least one isocyanurate, biuret, uretdione and / or allophanate group and is composed of aliphatic and / or cycloaliphatic isocyanates,

 under reaction conditions under which urethane groups are formed between (A) and (B), with the proviso that

 - The molar ratio of NCO groups to OH groups between (B) and (A) is at least 3: 1.

Highly functional urethane-containing polyisocyanates according to Claim 1, characterized in that the polyisocyanate (B) is isocyanurate-group-containing polyisocyanates based on 1,6-hexamethylene diisocyanate having a viscosity of 600-3000 mPa * s.

Highly functional urethane-containing polyisocyanates according to claim 1, characterized in that the trialkanolamine (A) is selected from the group consisting of 5- [bis (2'-hydroxyethyl) amino] -3-oxa-pentane-1-ol, triethanolamine, tripropanol - min, N-ethyldiethanolamine, N-methyldiethanolamine and N-butyldiethanolamine.

High-functionality urethane-containing polyisocyanates according to Claim 3, characterized in that the trialkanolamine (A) is triethanolamine.

High-functionality urethane-containing polyisocyanates according to Claim 1, characterized in that, in addition to the compound (A), 10 to 70% of the total amount of hydroxyl groups used originates from a diol (A1) and / or polyol (A2).

Use of high-functionality urethane-containing polyisocyanates according to one of the preceding claims in two-component coating compositions.

Two-component coating compositions containing

 at least one highly functional urethane group-containing polyisocyanate according to any one of claims 1 to 6,

 at least one compound having at least 2 isocyanate-reactive groups,

- Optional solvents, pigments, additives and / or thickeners. A process for the preparation of polyurethane coatings, which comprises reacting a highly functional urethane polyisocyanate according to any one of claims 1 to 6 with at least one binder containing isocyanate-reactive groups.

A process for the preparation of polyurethane paints, characterized in that one has a high-functionality urethane polyisocyanate according to any one of claims 1 to 6 with at least one binder selected from the group consisting of polyacrylate, polyester, polyether, polyurethane polyols, polyurea polyols, polyetherols, polycarbonates, Polyesterpolyacrylatpolyolen , Polyester polyurethane polyols, polyurethane polyacrylate polyols, polyurethane-modified alkyd resins, fatty acid-modified polyester polyurethane polyols, copolymers with allyl ethers and co- or graft polymers from the substance groups mentioned.

Use of highly functional urethane-containing polyisocyanates according to any one of claims 1 to 6 as a curing agent in polyurethane coatings.

Use of highly functional urethane-containing polyisocyanates according to any one of claims 1 to 6 as a curing agent in refinish, wood or Großfahrzeug- coatings.

Use of high-functionality urethane-containing polyisocyanates according to any one of claims 1 to 6 as hardeners in paints, adhesives and Dichtungsmas sen.