Polyisocyanate mixture

Abstract

The invention relates to a polyisocyanate mixture, to a method for the production thereof, and to the use of the polyisocyanate mixture. The invention also relates to a composition containing the polyisocyanate mixture, a method for producing a coating on a substrate, and to the coated substrate.

Description

[0001] Polyisocyanate mixture

[0002] The invention relates to a polyisocyanate mixture, a process for its preparation, and the use of the polyisocyanate mixture. Further subjects of the invention are a composition containing the polyisocyanate mixture, a process for producing a coating on a substrate, and the coated substrate.

[0003] Solvent-free two-component (2K) polyurethane, polyurea, and polythiourethane coatings can be applied in virtually any desired thickness, unlike solvent-based paints. Today, they are primarily used in the construction industry for producing thick coatings, for example, for coating surfaces subject to high mechanical or chemical stress, such as industrial floors, traffic areas, parking decks, for balcony sealing, and also for corrosion protection.

[0004] For outdoor applications, highly elastic crack-bridging coatings that exhibit high stability against weather exposure, especially against UV radiation, are of particular interest.

[0005] Solvent-free two-component coatings absolutely require liquid, low-viscosity reactants. While a range of suitable polyols, polyamines, and polythiols with sufficiently low viscosity are available, such as polyether polyols, slightly branched polyester polyols, polyetheramines, or polyaspartic acid esters, oligomeric polyisocyanates based on linear aliphatic diisocyanates, particularly polyisocyanates of hexamethylene diisocyanate (1,6-diisocyanatohexane, HDI), are preferably used as crosslinking components for the production of elastic coatings.

[0006] HDI polyisocyanates, such as the HDI derivatives known as paint polyisocyanates with uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure, are characterized by low viscosities even in solvent-free form and are known to produce highly weather-resistant, flexible paint films.

[0007] Despite the high quality level already achieved by 2K polyurethane or polyurea coatings, there is a constant interest in the market for coating systems with ever-improving properties, in particular improved elasticity, which, for example, enable the formulation of floor coatings with high walking comfort.

[0008] The trend toward more sustainable products has led to increasing demand for bio-based raw materials in recent years, including in the polyurethane sector. This prompted the development of polyisocyanate crosslinkers based on 1,5-diisocyanatopentane (hereinafter also referred to as pentamethylene diisocyanate or PDI), which is accessible from biomass (see, for example, EP-A 3 271 432 and WO 2016 / 169810). PUR coatings and adhesives produced using bio-based PDI polyisocyanates exhibit a similar level of properties to those crosslinked with comparable petrochemical-based HDI polyisocyanates, and are even superior in some applications.

[0009] A serious disadvantage of PDI polyisocyanates, however, is the fact that they exhibit higher viscosities than corresponding HDI derivatives with a comparable oligomer distribution (M. Widemann et al., ACS Sustainable Chem. Eng. 2018, 6, 9753-9759; DOI: http: / / dx.doi.org / 10.1021 / acssuschemeng.8b00758), and their processing generally requires larger quantities of organic solvents. However, especially for the production of sustainable, thick-film coatings, coating systems with the lowest possible content of volatile organic components, preferably solvent-free, are desired.

[0010] Particularly for applications in the construction sector, for example for floor coating or balcony sealing, there was therefore a need for sustainable polyisocyanate mixtures that have sufficiently low viscosities to enable them to be processed in low-solvent or solvent-free form.

[0011] The object of the present invention was therefore to provide sustainable polyisocyanate mixtures which have sufficiently low viscosities to enable them to be processed in low-solvent, preferably solvent-free form, and which lead to coatings with improved elasticity.

[0012] Taking this need into account, the present invention relates to a polyisocyanate mixture containing at least one polyisocyanate M) of the general formula (I) in which

[0013] R represents a linear or branched, saturated or unsaturated aliphatic and / or saturated or unsaturated cycloaliphatic radical having (6 to 22) - p carbon atoms, each of which may optionally be substituted, R' and R" independently represent hydrogen or an aliphatic radical having 1 to 10 carbon atoms, where at least one of the radicals R' and R" represents hydrogen, n represents an integer from 1 to 12, m represents an integer from 1 to 10 and p represents 0 or 1, and at least one polyisocyanate N) different from polyisocyanate M) with uretdione, isocyanurate, iminooxadiazinedione, urethane, allophanate, biuret and / or oxadiazinetrione structure, which carry aliphatically, cycloaliphatically, araliphatically and / or aromatically bound isocyanate groups, where the polyisocyanates are in a Weight ratio of M) to N) of 40 : 60 to 90 : 10.

[0014] The invention also relates to a process for the preparation of the polyisocyanate mixtures according to the invention, characterized in that at least one polyisocyanate M) of the general formula (I) in which

[0015] R represents a linear or branched, saturated or unsaturated aliphatic and / or saturated or unsaturated cycloaliphatic radical having (6 to 22) - p carbon atoms, each of which may optionally be substituted,

[0016] R' and R" independently of one another represent hydrogen or an aliphatic radical having 1 to 10 carbon atoms, where at least one of the radicals R' and R" represents hydrogen, n represents an integer from 1 to 12, m represents an integer from 1 to 10 and p represents 0 or 1 with at least one polyisocyanate N) different from polyisocyanate M) having a uretdione, isocyanurate, iminooxadiazinedione, urethane, allophanate, biuret and / or oxadiazinetrione structure which carries aliphatically, cycloaliphatically, araliphatically and / or aromatically bound isocyanate groups, so that the polyisocyanates M) and N) are mixed in a weight ratio to one another of 40:60 to 90:10, preferably of 40:60 to 85:15 and particularly preferably of 50:50 to 80 : 20, are present.

[0017] According to the invention, the terms "comprising" and "containing" preferably mean "consisting essentially of" and particularly preferably "consisting of." The further embodiments mentioned in the claims and in the description can be combined as desired, unless the context clearly indicates otherwise.

[0018] "At least one," as used herein, refers to 1 or more, for example, 2, 3, 4, 5, 6, 7, 8, 9, or more. In the context of components of the compounds described herein, this statement does not refer to the absolute amount of molecules, but rather to the type of component. "At least one polyisocyanate" therefore means, for example, that only one type of polyisocyanate or several different types of polyisocyanates may be present, without specifying the amount of the individual components.

[0019] Numerical values ​​stated without decimal places refer to the full specified value with one decimal place. For example, "99%" stands for "99.0%."

[0020] Numerical ranges specified in the format "in / from x to y" include the specified values. If multiple preferred numerical ranges are specified in this format, it is understood that all ranges resulting from the combination of the different endpoints are also included.

[0021] For the purposes of this document, the term "aliphatic" is defined as non-aromatic hydrocarbon groups that are saturated or unsaturated.

[0022] Here, the term "araliphatic" is defined as aliphatic hydrocarbon radicals that are saturated or unsaturated and have at least one aromatic substituent.

[0023] For the purposes of this document, the term "alicyclic" or "cycloaliphatic" is defined as optionally substituted, carbocyclic, or heterocyclic compounds or moieties that are not aromatic (such as cycloalkanes, cycloalkenes, or oxa-, thia-, aza-, or thiazacycloalkanes). Specific examples include cyclohexyl groups, cyclopentyl groups, and their N- or O-heterocyclic derivatives, such as pyrimidine, pyrazine, tetrahydropyran, or tetrahydrofuran.

[0024] In the event that the groups or compounds are disclosed as "optionally substituted" or "substituted," suitable substituents are -F, -Cl, -Br, -I, -OH, -OCH3, OCH2CH3, -O-isopropyl or -on-propyl, -OCF3, -CF3, -S-C1-6-alkyl, and / or (optionally via an attached heteroatom) a linear or branched, aliphatic and / or alicyclic structural unit having 1 to 12 carbon atoms, each acting as a replacement for a carbon-bonded hydrogen atom of the molecule in question. Preferred substituents are halogen (especially -F, -Cl), C1-6-alkoxy (especially methoxy and ethoxy), hydroxy, trifluoromethyl, and trifluoromethoxy, each acting as a replacement for a carbon-bonded hydrogen atom of the molecule in question.

[0025] The general term “polyurethanes” is used below as a synonym for the multitude of different polymers with, for example, urethane, urea and / or thiourethane structures, which can be produced from polyisocyanates and H-acidic compounds, such as polyols, polyamines and / or polythiols.

[0026] The polyisocyanate mixture according to the invention represents a physical mixture and thus differs from a polyisocyanate produced purely chemically in a direct way, for example with regard to the oligomer distribution which can be determined by gel permeation chromatography according to DIN EN ISO 13885-1:2021-11.

[0027] In a first preferred embodiment of the polyisocyanate mixture according to the invention, the polyisocyanates M) and N) are present in a weight ratio to one another of 40:60 to 85:15, preferably 50:50 to 80:20.

[0028] In a further preferred embodiment, the polyisocyanate mixture according to the invention has, in each case based on the solvent-free solid resin, color numbers of less than 100 APHA, preferably of less than 80 APHA, particularly preferably of less than 60 APHA, and / or an NCO content of 6.8 to 19.6 wt.%, preferably 6.8 to 19.2 wt.%, particularly preferably 7.0 to 18.8 wt.%, and / or a residual monomer content measured by gas chromatography with an internal standard according to DIN EN ISO 10283:2007-11 of less than 0.14 wt.%, preferably less than 0.12 wt.% and particularly preferably less than 0.10 wt.%.

[0029] In a further preferred embodiment, the polyisocyanate mixture according to the invention has a shear strength according to DIN EN ISO 3219:1994-10 at a shear rate of 250 s -1 measured viscosity at 23°C of less than 3000 mPas, preferably less than 2000 mPas and particularly preferably less than 1500 mPas.

[0030] The at least one polyisocyanate M) is mixed with the at least one polyisocyanate N) such that the polyisocyanate mixture according to the invention is obtained and the polyisocyanates M) and N) are present in the above-mentioned weight ratio to one another. By suitable choice of the mixing ratios within the stated limits, properties such as viscosity, NCO content and functionality of the process products according to the invention can be specifically adjusted. Mixing is carried out by any desired methods and in any desired sequence, at a temperature of 0 to 60°C, preferably 10 to 50°C, particularly preferably 20 to 40°C, optionally under an inert gas atmosphere, preferably with exclusion of moisture. The process according to the invention is preferably carried out solvent-free. If appropriate, however, suitable solvents which are reactive towards the groups of the starting polyisocyanates

[0031] M) and N) inert solvents are used. Suitable solvents for this purpose include those made from fossil raw materials or from renewable raw materials, in particular the conventional paint solvents known per se, such as:Ethyl acetate, butyl acetate, ethylene glycol monomethyl or ethyl ether acetate, 1-methoxypropyl-2-acetate, 3-methoxy-n-butyl acetate, ethyl(-)-L-lactate, acetone, 2-butanone, 4-methyl-2-pentanone, cyclohexanone, dihydrolevoglucosenone, toluene, xylene, chlorobenzene, white spirit, higher substituted aromatics, such as those sold under the names Solventnaphtha, Solvesso®, Isopar®, Nappar®, Varsol® (ExxonMobil Chemical Central Europe, Cologne, DE) and Shellsol® (Shell Deutschland Oil GmbH, Hamburg, DE), but also solvents such as dimethylfuran, 2-methyltetrahydrofuran, dimethylisosorbide (DMI), γ-valerolactone, propylene glycol diacetate, diethylene glycol dimethyl ether, Dipropylene glycol dimethyl ether, diethylene glycol ethyl and butyl ether acetate, N-methylpyrrolidone and N-methylcaprolactam, or any mixtures of such solvents.

[0032] In a preferred embodiment of the process according to the invention, 40 to 90 parts by weight, particularly preferably 40 to 85 parts by weight, very particularly preferably 50 to 80 parts by weight of the polyisocyanate M) and 10 to 60 parts by weight, preferably 15 to 60 parts by weight, very particularly preferably 20 to 80 parts by weight of the polyisocyanate N) are mixed. When one or more solvents are used, these can be present either in the at least one polyisocyanate M) and / or in the at least one polyisocyanate

[0033] N), preferably in the at least one polyisocyanate N) already before mixing begins. However, in the process according to the invention, they can also be added after completion or at any time during the actual mixing process.

[0034] If at all, solvents are used in the process according to the invention in an amount of up to 40 wt.%, preferably 30 wt.%, particularly preferably 20 wt.%, based on the sum of polyisocyanate M), polyisocyanate N) and solvent.

[0035] The polyisocyanates M) and N) are further described below and preferred embodiments are mentioned.

[0036] Polyisocyanate M)

[0037] The polyisocyanate M) is a special PDI allophanate polyisocyanate and is described by the general formula (I). A general formula (I) of the at least one polyisocyanate M) is preferred. in which

[0038] R represents a linear or branched, saturated or unsaturated aliphatic and / or saturated or unsaturated cycloaliphatic radical having (8 to 20) - p, particularly preferably having (10 to 18) - p and very particularly preferably having (12 to 14) - p carbon atoms, which may optionally be substituted,

[0039] R' and R" independently of one another represent hydrogen or an aliphatic radical having 1 to 10 carbon atoms, where at least one of the radicals R' and R" represents hydrogen, n represents an integer from 1 to 12, m represents an integer from 1 to 7, particularly preferably an integer from 2 to 5 and most particularly preferably an integer from 2 to 4, and p represents 0 or 1.

[0040] The 1,5-diisocyanatopentane (here also referred to as pentamethylene diisocyanate or PDI) used to produce the polyisocyanate M) can be produced in various ways, for example by phosgenation in the liquid or gas phase or by a phosgene-free route, such as by thermal urethane cleavage, starting from 1,5-diaminopentane preferably obtained biotechnologically by decarboxylation of the naturally occurring amino acid lysine.

[0041] A further preferred embodiment relates to a process for the preparation of the polyisocyanate M) by reacting 1,5-diisocyanatopentane with at least one alcohol B) of the general formula (II) which

[0042] R represents a linear or branched, saturated or unsaturated aliphatic and / or saturated or unsaturated cycloaliphatic radical with (6 to 22) - p

[0043] carbon atoms, each of which may optionally be substituted,

[0044] R' and R“ independently represent hydrogen or an aliphatic radical with 1 to

[0045] 10 carbon atoms, where at least one of the radicals R' and R“ is

[0046] stands for hydrogen, m stands for an integer from 1 to 10 and p stands for 0 or 1.

[0047] Preference is given to 1,5-diisocyanatopentane with at least one alcohol B) of the general

[0048] Formula (II) is implemented, which

[0049] R represents a linear or branched, saturated or unsaturated aliphatic and / or saturated or unsaturated cycloaliphatic radical having (6 to 22) - p carbon atoms, each of which may optionally be substituted,

[0050] R' and R" independently of one another represent hydrogen or an aliphatic radical having 1 to 10 carbon atoms, where at least one of the radicals R' and R" represents hydrogen, m represents an integer from 1 to 10 and p represents 0 or 1.

[0051] As alcoholic component B) in the production of the polyisocyanate M) at least one alcohol of the general formula (II) is used, used in which

[0052] R represents a linear or branched, saturated or unsaturated aliphatic and / or saturated or unsaturated cycloaliphatic radical having (6 to 22) - p, preferably having (8 to 20) - p, particularly preferably having (10 to 18) - p and very particularly preferably having (12 to 14) - p carbon atoms, which may in each case be optionally substituted,

[0053] R' and R" independently of one another represent hydrogen or an aliphatic radical having 1 to 10 carbon atoms, where at least one of the radicals R' and R" represents hydrogen, and m represents an integer from 1 to 10, preferably an integer from 1 to 7, more preferably an integer from 2 to 5 and most preferably an integer from 2 to 4, and p represents 0 or 1.

[0054] These alcohols are, for example, the known alkoxylation products of fatty alcohols of the general formula (III)

[0055] R 1 -OH (Hi), in which

[0056] R 1represents a linear or branched, saturated or unsaturated aliphatic and / or saturated or unsaturated cycloaliphatic radical having 6 to 22, preferably 8 to 20, particularly preferably 10 to 18, very particularly preferably 12 to 14 carbon atoms, each of which may optionally be substituted, and / or fatty acids of the general formula (IV)

[0057] R 2 -COOH (IV), in which

[0058] R 2 represents a linear or branched, saturated or unsaturated aliphatic and / or saturated or unsaturated cycloaliphatic radical having 5 to 21, preferably 7 to 19, particularly preferably 9 to 17, very particularly preferably 11 to 13 carbon atoms, which may in each case be optionally substituted.

[0059] In the above-mentioned fatty alcohols of the general formula (III), in the general formula (I) and the general formula (II) p stands for 0 and R 1for R, including the preferences mentioned for R 1 . Likewise, residues R 1 and also R are examples of suitable, preferred and particularly preferred radicals derived from the fatty alcohols mentioned below as examples of suitable, preferred and particularly preferred.

[0060] For the above-mentioned fatty acids of the general formula (IV), in the general formula (I) and the general formula (II) p stands for 1 and R 2 for R, including the preferences mentioned for R 2 . Likewise, residues R 2 and also R are mentioned as examples of suitable, preferred and particularly preferred radicals derived from the fatty acids mentioned below as examples of suitable, preferred and particularly preferred.

[0061] Fatty alcohols suitable for alkoxylation are, for example, 1-hexanol (caproic alcohol), 1-heptanol (enanth alcohol), 1-octanol (caprylic alcohol), 1-nonyl alcohol (pelargon alcohol), 1-decanol (capric alcohol), 1-dodecanol (lauryl alcohol), 1-tetradecanol (myristyl alcohol), 1-hexadecanol (cetyl alcohol), 1-heptadecanol (margaryl alcohol), 1-octadecanol (stearyl alcohol), 1-eicosanol (arachidyl alcohol), 1-docosanol (behenyl alcohol), 1-tetracosanol (lignoceryl alcohol), 1-hexacosanol (ceryl alcohol), 1-octacosanol (montanyl alcohol), 1-triacontanol (melissyl alcohol), c / s-9-hexadecen-1-ol (palmitoleyl alcohol), c / s-9-octadecen-1-ol (oleyl alcohol), trans-9-octadecen-1-ol (elaidyl alcohol), c / s-11-octadecen-1-ol, c / s,c / s-9,12-octadecadien-1-ol (linoleyl alcohol) and 6,9,12-octadecatrien-1-ol (γ-linolenyl alcohol). Suitable fatty acids include, for example, hexanoic acid (caproic acid), heptanoic acid (enanthic acid), octanoic acid (caprylic acid), nonanoic acid (pelargonic acid), decanoic acid (capric acid).Undecanoic acid, dodecanoic acid (lauric acid), tridecanoic acid, tetradecanoic acid (myristic acid), pentadecanoic acid, hexadecanoic acid (palmitic acid), heptadecanoic acid (margaric acid), octadecanoic acid (stearic acid), nonadecanoic acid, eicosanoic / icosanoic acid (arachidic acid), heneicosanoic acid and docosanoic acid (behenic acid), c / s-9-octadecenoic acid (oleic acid) and c / s-13-docosenoic acid (erucic acid).

[0062] Preferred fatty alcohols and fatty acids are those produced using vegetable and animal oils and fats.

[0063] Particularly preferred fatty alcohols for preparing the alcoholic component B) are 1-decanol, 1-dodecanol, 1-tetradecanol, and 1-octadecanol, very particularly preferably 1-dodecanol and 1-tetradecanol. Particularly preferred fatty acids are decanoic acid, dodecanoic acid, tetradecanoic acid, and hexadecanoic acid, very particularly preferably dodecanoic acid and tetradecanoic acid. For preparing the alcoholic component B) by alkoxylation of the fatty alcohols and / or fatty acids mentioned, any alkylene oxides having 2 to 12 carbon atoms, such as ethylene oxide, propylene oxide, 1,2-epoxybutane, 1,2-epoxyhexane, 1,2-epoxyoctane, or 1,2-epoxydodecane, are suitable; these can be used in any order or as a mixture in the alkoxylation reaction. Preferred alkylene oxides are those having 2 to 4 carbon atoms. Particularly preferred alkylene oxides for the preparation of the alcoholic component B) are ethylene oxide and propylene oxide.

[0064] The number of carbon atoms of the radicals R' or R" in the general formula (I) results from the alkylene oxides mentioned above as examples and with preference. Thus, R' and R" in the general formula (I) and / or formula (II) independently of one another represent hydrogen or an aliphatic radical having preferably 1 to 2 carbon atoms, where at least one of the radicals R' and R" represents hydrogen.

[0065] Suitable alcoholic components B) for preparing the polyisocyanates M) are, in particular, alkoxylation products of the fatty acids and / or fatty alcohols mentioned, which have an average of 1 to 10, preferably 1 to 7, particularly preferably 2 to 5, and most preferably 2 to 4 alkylene oxide units. The numbers and numerical ranges mentioned above as averages result in the inventive and preferred integers m in the general formula (I) and the general formula (II).

[0066] In a further preferred embodiment, alkoxylation products containing an average of 1 to 10, preferably 1 to 7, particularly preferably 2 to 5, and most particularly preferably 2 to 4, alkylene oxide units are used as alcoholic component B), the alkylene oxide units preferably comprising or consisting of ethylene oxide and / or propylene oxide units. The numbers and numerical ranges mentioned above as statistical averages result in the inventive and preferred integers m in general formula (I) and general formula (II).

[0067] The alcoholic components B) preferably have a pH, measured on a 1% solution of the respective alcoholic component B) in water, of 4.0 to 8.0, preferably of 4.5 to 7.5, particularly preferably of 5.0 to 7.0 and / or total contents of alkali cations of at most 100 ppm, preferably of 1 to 70 ppm, particularly preferably of 2 to 50 ppm.

[0068] If necessary, component B) may contain, in addition to the alkoxylation products of fatty alcohols and / or fatty acids mentioned, other alcoholic compounds in minor amounts.

[0069] These include, for example, monoalcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, the isomeric pentanoyl, hexanoyl, octanols and nonanols, n-decanol, n-dodecanol, n-tetradecanol, n-hexadecanol, n-octadecanol, cyclohexanol, the isomeric methylcyclohexanols, hydroxymethylcyclohexane, 3-methyl-3-hydroxymethyloxetane, benzyl alcohol, phenol, the isomeric cresols, octylphenols, nonylphenols and naphthols, furfuryl alcohol and tetrahydrofurfuryl alcohol, unbranched aliphatic diols such as. B. 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol and 1,8-octanediol, cycloaliphatic diols, such as B. 1,2- and 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 4,4'-(1-methylethylidene)-biscyclohexanol, triols such as B. 1,2,3-propanetriol, 1,1,1-trimethylolethane, 1,2,6-hexanetriol, 1,1,1-trimethylolpropane, and 1,3,5-tris(2-hydroxyethyl)isocyanurate, tetrafunctional alcohols, such as B.B. 2,2-bis(hydroxymethyl)-1,3-propanediol or any mixtures of such alcohols.

[0070] If at all, these further alcoholic compounds are used to produce the polyisocyanate M) in amounts of not more than 25% by weight, preferably not more than 20% by weight, particularly preferably not more than 15% by weight, based on the amount of alkoxylation products of fatty alcohols and / or fatty acids used.

[0071] To prepare the polyisocyanate M), 1,5-diisocyanatopentane is reacted with at least one alcoholic component B), preferably at temperatures of 40 to 200 °C, particularly preferably 60 to 180 °C, and / or maintaining an equivalent ratio of isocyanate groups to isocyanate-reactive groups of preferably 4:1 to 50:1, particularly preferably 5:1 to 30:1, very particularly preferably 10:1 to 25:1, to form allophanate polyisocyanates.

[0072] The process for preparing the polyisocyanate M) can be carried out uncatalyzed as a thermally induced allophanatization. However, suitable catalysts are preferably used to accelerate the allophanatization reaction. These catalysts are the customary known allophanatization catalysts, for example metal carboxylates, metal chelates, or tertiary amines of the type described in GB-A-0994890 (page 2, lines 73 to 87), alkylating agents of the type described in US-A-3,769,318 (column 6, lines 5 to 49), or strong acids, as described by way of example in EP-A-0 000 194 (page 13, line 27 to page 14, lines 1 to 18).

[0073] Suitable allophanatization catalysts are in particular zinc compounds, such as zinc (II) stearate, zinc (II) n-octanoate, zinc (II) 2-ethyl-1-hexanoate, zinc (II) naphthenate or zinc (II) acetylacetonate, tin compounds, such as tin (II) n-octanoate, tin (II) 2-ethyl-1-hexanoate, tin (II) laurate, dibutyltin oxide, dibutyltin dichloride, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dimaleate or dioctyltin diacetate, zirconium compounds, such as. B. Zirconium (IV) 2-ethyl-1-hexanoate, zirconium (IV) neodecanoate, zirconium (IV) naphthenate or zirconium (IV) acetylacetonate, aluminum tri(ethylacetoacetate), iron (III) chloride, potassium octoate, manganese, cobalt or nickel compounds and strong acids, such as B. trifluoroacetic acid, sulfuric acid, hydrogen chloride, hydrogen bromide, phosphoric acid or perchloric acid, or any mixtures of these catalysts.

[0074] Suitable, albeit less preferred, catalysts for the preparation of polyisocyanate M) are also those compounds that, in addition to the allophanatization reaction, also catalyze the trimerization of isocyanate groups to form isocyanurate structures. Such catalysts are described, for example, in EP-A-0 649 866, page 4, line 7 to page 5, line 15.

[0075] Preferred catalysts for preparing the polyisocyanate M) are zinc and / or zirconium compounds of the abovementioned type. Very particular preference is given to using at least zinc(II)n-octanoate, zinc(II)2-ethyl-1-hexanoate and / or zinc(II)stearate, zirconium(IV)n-octanoate, zirconium(IV)2-ethyl-1-hexanoate and / or zirconium(IV)neodecanoate.

[0076] These catalysts are used in the preparation of the polyisocyanate M), if at all, preferably in an amount of 0.001 to 5 wt.%, particularly preferably 0.005 to 1 wt.%, based on the total weight of the reactants A) and B), and can be added both before the start of the reaction and at any time during the reaction.

[0077] Lead octoate is preferably not used as a catalyst in the preparation of the polyisocyanates M), and thus a polyisocyanate mixture according to the invention is preferred which is free from catalytic amounts, particularly preferably free from detectable amounts of lead octoate. The polyisocyanate M) is preferably prepared solvent-free. However, suitable solvents that are inert toward the reactive groups of the starting components can also be used if desired. Suitable solvents include, for example, the solvents described above as suitable solvents for the process according to the invention or any mixtures of such solvents.

[0078] In one possible embodiment, in the preparation of the polyisocyanate M), the PDI is initially charged at a temperature between 20 and 100°C - optionally under an inert gas, such as nitrogen, and optionally in the presence of a suitable solvent of the type mentioned. The alcoholic component B) is then added in the amount stated above, and the reaction temperature for the urethanization is adjusted, if appropriate by a suitable measure (heating or cooling), to a temperature of 30 to 120°C, preferably 50 to 100°C. Following the urethanization reaction, i.e. when the NCO content theoretically corresponding to complete conversion of isocyanate and hydroxyl groups has been reached, the allophanatization can be started, for example without the addition of a catalyst, by heating the reaction mixture to a temperature of 140 to 200°C.However, suitable catalysts of the above-mentioned type are preferably used to accelerate the allophanatization reaction, temperatures in the range from 60 to 140°C, preferably 80 to 120°C, generally being sufficient, depending on the type and amount of catalyst used.

[0079] In another possible embodiment of the process for preparing the polyisocyanate M), the optionally used catalyst is admixed to the PDI and / or the alcoholic component B) before the start of the actual reaction. In this case, the intermediately formed urethane groups spontaneously react further to form the desired allophanate structure. In this type of single-stage reaction, the PDI, optionally containing the catalyst, is initially introduced - optionally under an inert gas such as nitrogen, and optionally in the presence of a suitable solvent of the type mentioned - generally at temperatures optimal for allophanatization in the range of 60 to 140°C, preferably 80 to 120°C, and reacted with the alcoholic component B), optionally containing the catalyst.

[0080] However, it is also possible to add the catalyst to the reaction mixture at any time during the urethanization reaction. In this embodiment of the process, a temperature in the range of 30 to 120°C, preferably 50 to 100°C, is generally set for the pure urethanization reaction, which takes place before the catalyst addition. After adding a suitable catalyst, the allophanatization reaction is finally carried out at temperatures of generally 60 to 140°C, preferably 80 to 120°C.

[0081] The progress of the reaction in the process for preparing the polyisocyanate M) can be monitored, for example, by titrimetric determination of the NCO content in accordance with DIN EN ISO 11909:2007-05. Once the desired NCO content has been reached, preferably when the degree of allophanatization (i.e. the percentage of urethane groups converted to allophanate groups, which form intermediately from the hydroxyl groups of component B), which can be calculated from the NCO content, of the reaction mixture is at least 80%, particularly preferably at least 90%, and very particularly preferably when the NCO content corresponding to complete allophanatization has been reached or fallen below, the reaction is terminated. In the case of a purely thermal reaction, this can be achieved, for example, by cooling the reaction mixture to room temperature.However, with the preferred use of an allophanatization catalyst of the type mentioned, the reaction is generally stopped by adding suitable catalyst poisons, for example acids such as phosphoric acid, or acid chlorides such as benzoyl chloride or isophthaloyl dichloride.

[0082] The reaction mixture is then preferably freed from volatile constituents (excess PDI, any solvents used and, if no catalyst poison is used, any active catalyst) by thin-film distillation in a high vacuum, for example at a pressure of less than 1.0 mbar, preferably less than 0.5 mbar, particularly preferably less than 0.2 mbar, under the gentlest possible conditions, for example at a temperature of 100 to 200 °C, preferably 120 to 180 °C.

[0083] The resulting distillates, which contain, in addition to the unreacted PDI and any solvents used, if no catalyst poison is used, possibly active catalyst, can be used without any problem for further allophanatization in the process for the production of the polyisocyanate M).

[0084] In a further embodiment of the process for preparing the polyisocyanate M), the volatile components mentioned are separated from the oligomerization product by extraction with suitable solvents inert to isocyanate groups, for example aliphatic or cycloaliphatic hydrocarbons such as pentane, hexane, heptane, cyclopentane or cyclohexane.

[0085] Regardless of the type of process for their preparation, the polyisocyanates M) are clear, virtually colorless polyisocyanates which, in each case based on the solvent-free solid resin, have color numbers of less than 100 APHA, preferably of less than 80 APHA, particularly preferably of less than 60 APHA, and / or an NCO content of 6.0 to 18.0 wt.%, preferably 8.0 to 16.0 wt.%, particularly preferably 10.0 to 15.0 wt.%, and / or a residual monomer content of less than 0.14 wt.%, preferably less than 0.12 wt.% and particularly preferably less than 0.10 wt.%, measured by gas chromatography with an internal standard in accordance with DIN EN ISO 10283:2007-11.

[0086] The viscosities of the polyisocyanates M) measured according to DIN EN ISO 3219:1994-10 at a shear rate of 250 s-1 at 23°C are preferably less than 500 mPas, particularly preferably less than 400 mPas, most preferably less than 300 mPas.

[0087] Polyisocyanate N)

[0088] Polyisocyanates N) for the polyisocyanate mixture according to the invention and the process according to the invention are any polyisocyanates having a uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure prepared by modifying simple aliphatic, cycloaliphatic, araliphatic and / or aromatic diisocyanates and / or triisocyanates, as described, for example, in J. Prakt. Chem. 336 (1994) 185 - 200, in DE-A 1 670 666, DE-A 1 954 093, DE-A 2 414 413, DE-A 2 452 532, DE-A 2 641 380, DE-A 3 700 209, DE-A 3 900 053 and DE-A 3 928 503 or in EP-A 0 336 205, EP-A 0 339 396 EP-A 0 798 299, EP-A 0 962 454, EP-A 0 962 455, EP-A 2 785 760, EP-A 2 883 895, EP-A 3 107 922, EP-A 3 107 948 and EP-A 3 337 836 or any mixtures of such polyisocyanates.

[0089] Suitable diisocyanates and triisocyanates A) are any diisocyanates and triisocyanates which can be obtained in various ways, for example by phosgenation of the corresponding diamines or triamines, which can be produced using fossil raw materials or else from renewable raw materials, optionally with a mass balance, in the liquid or gas phase or by a phosgene-free route, such as by thermal urethane cleavage, preferably those in the molecular weight range 140 to 400 with aliphatically, cycloaliphatically, araliphatically and / or aromatically bound isocyanate groups, such as, for example, B. 1,4-diisocyanatobutane, 1,5-diisocyanatopentane (PDI), 1,6-diisocyanatohexane (HDI), 2-methyl-1,5-diisocyanatopentane, 1,5-diisocyanato-2,2-dimethylpentane, 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanatohexane, 1,8-diisocyanatooctane, 1,9-diisocyanatononane, 1,10-diisocyanatodecane, 1,3- and 1,4-diisocyanatocyclohexane, 1,3- and 1,4-bis-(isocyanatomethyl)-cyclohexane,1-lsocyanato-3,3,5-trimethyl-5- isocyanatomethylcyclohexan (Isophorondiisocyanat, IPDI), 2,4’- und 4,4'-Diiso- cyanatodicyclohexylmethan (H12-MDI), 4,4'-Diisocyanato-3,3'-dimethyldicyclohexylmethan, 4,4'-Diisocyanato-3,3',5,5'-tetramethyldicyclohexylmethan, 4,4'-Diisocyanato-1 ,T- bi(cyclohexyl), 4,4'-Diisocyanato-3,3'-dimethyl-1 ,1'-bi(cyclohexyl), 4,4'-Diisocyanato-2,2',5,5'- tetra-methyl-1 ,1'-bi(cyclohexyl), 1 ,8-Diisocyanato-p-menthan, 1 ,3-Diisocyanatoadamantan, 1 ,3-Dimethyl-5,7-diisocyanatoadamantan, 1-lsocyanato-1-methyl-4(3)isocyanato- methylcyclohexan, Bis-(isocyanatomethyl)-norbornan (NBDI), 4-lsocyanatomethyl-1 ,8- octandiisocyanat (Triisocyanatononan; TIN), 1 ,3- und 1 ,4-Bis(isocyanatomethyl)benzol (Xylylendiisocyanat, XDI), 1 ,3- und 1 ,4-Bis-(2-isocyanato-prop-2-yl)-benzol (TMXDI), 1 ,3- Bis(isocyanatomethyl)-4-methylbenzol, 1 ,3-Bis(isocyanatomethyl)-4-ethylbenzol, 1 ,3- Bis(isocyanatomethyl)-5-methylbenzol, 1 ,3-Bis(isocyanatomethyl)-4,5-dimethylbenzol, 1 ,4-bis(isocyanatomethyl)-2,5-dimethylbenzene, 1,4-bis(isocyanatomethyl)-2,3,5,6-tetramethylbenzene, 1,3-bis(isocyanatomethyl)-5-tert-butylbenzene, 1,3-bis(isocyanatomethyl)-4-chlorobenzene, 1,3-bis(isocyanatomethyl)-4,5-dichlorobenzene, 1,3-bis(isocyanatomethyl)-2,4,5,6-tetrachlorobenzene, 1,4-bis(isocyanatomethyl)-2,3,5,6-tetrachlorobenzene, 1,4-bis(isocyanatomethyl)-2,3,5,6-tetrabromobenzene, 1,4-bis(2-isocyanatoethyl)benzene and 1,4-bis(isocyanatomethyl)naphthalene, 1,2-, 1 ,3- and 1 ,4-diisocyanatobenzene,

[0090] (phenylene diisocyanate), 2,4- and 2,6-diisocyanatotoluene (TDI), 2,3,5,6-tetramethyl-1,4-diisocyanatobenzene, the isomeric diethylphenylene diisocyanates,

[0091] Diisopropylphenylene diisocyanates, diisododecylphenylene diisocyanates and

[0092] Biphenyl diisocyanates, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, 2,2'-, 2,4'- and 4,4'-diisocyanatodiphenylmethane (MDI), 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 4,4'-diisocyanatodiphenylethane, 1 ,5-Diisocyanatonaphthalene (naphthylene diisocyanate, NDI), diphenyl ether diisocyanate, ethylene glycol diphenyl ether diisocyanate,

[0093] Diethylene glycol diphenyl ether diisocyanate, 1,3-propylene glycol diphenyl ether diisocyanate, benzophenone diisocyanate, triisocyanatobenzene, 2,4,6-triisocyanatotoluene,

[0094] Trimethylbenzene triisocyanate, diphenylmethane-2,4,4'-triisocyanate, 3-methyldiphenylmethane-4,6,4'-triisocyanate, the isomeric naphthalene triisocyanates and methylnaphthalene diisocyanates, triphenylmethane triisocyanate, 2,4-diisocyanato-1-[(5-isocyanato-2-methylphenyl)methyl]benzene or mixtures of at least two such diisocyanates and triisocyanates.

[0095] If appropriate, monoisocyanates, especially those in the molecular weight range from 99 to 300, such as n-butyl isocyanate, n-amyl isocyanate, n-hexyl isocyanate, n-heptyl isocyanate, n-octyl isocyanate, undecyl isocyanate, dodecyl isocyanate, tetradecyl isocyanate, cetyl isocyanate, stearyl isocyanate, cyclopentyl isocyanate, cyclohexyl isocyanate, 3- or 4-methylcyclohexyl isocyanate, benzyl isocyanate, phenyl isocyanate, or naphthyl isocyanate, may also be used in minor amounts when modifying the above-mentioned diisocyanates and / or triisocyanates to polyisocyanates N). If used at all, monoisocyanates are used in amounts of up to 30% by weight, preferably up to 20% by weight, particularly preferably up to 10% by weight, based on the total amount of mono-, di-, and triisocyanates.

[0096] In the preparation of polyisocyanates N), the actual modification reaction is generally followed by a further process step for separating the unreacted excess monomeric diisocyanates and / or triisocyanates and, if appropriate, monoisocyanates. This monomer separation is carried out by conventional methods, preferably by thin-film distillation under vacuum or by extraction with suitable solvents inert toward isocyanate groups, for example, aliphatic or cycloaliphatic hydrocarbons such as pentane, hexane, heptane, cyclopentane, or cyclohexane.

[0097] In a further preferred embodiment, the polyisocyanate N) has aliphatically, araliphatically and / or cycloaliphatically bound isocyanate groups, preferably based on 1,5-diisocyanatopentane, 1,6-diisocyanatohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, 1,3-bis(isocyanatomethyl)benzene, bis(isocyanatomethyl)norbornane and / or 4,4'-diisocyanatodicyclohexylmethane and particularly preferably contains at least isocyanurate structures based on 1,5-diisocyanatopentane, 1,6-diisocyanatohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, 1,3-bis(isocyanatomethyl)benzene, bis(isocyanatomethyl)norbornane and / or 4,4'-diisocyanatodicyclohexylmethane and very particularly preferably contains isocyanurate structures based on 1,5-diisocyanatopentane, 1,6-diisocyanatohexane and / or 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane.

[0098] Preferably, polyisocyanates of the type mentioned which have an isocyanate group content of 6.0 to 26.0 wt. %, preferably 8.0 to 25.0 wt. %, particularly preferably 10.0 to 24.0 wt. %, and a monomeric diisocyanate content of less than 0.14 wt. %, preferably less than 0.12 wt. %, particularly preferably less than 0.10 wt. % are used as polyisocyanate N) in the polyisocyanate mixture according to the invention. For the alternative, optional case in which triisocyanates and / or monoisocyanates were used to prepare the polyisocyanates N), the above-mentioned residual monomer contents of less than 0.14 wt. %, preferably less than 0.12 wt. %, particularly preferably less than 0.10 wt. % are based on the sum of all residual contents of all diisocyanates, triisocyanates and monoisocyanates used.The NCO contents are determined according to DIN EN ISO 11909:2007-05, the residual monomer contents according to DIN EN ISO 10283:2007-11 using gas chromatography with an internal standard.

[0099] Particularly preferred polyisocyanates N) for the polyisocyanate mixture according to the invention are those of the type mentioned with exclusively aliphatically and / or cycloaliphatically bound isocyanate groups.

[0100] Very particularly preferred polyisocyanates N) are polyisocyanates containing at least isocyanurate structures based on 1,5-diisocyanatopentane, 1,6-diisocyanatohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, 1,3-bis(isocyanatomethyl)benzene, bis(isocyanatomethyl)norbornane and / or 4,4'-diisocyanatodicyclohexylmethane and most preferably polyisocyanates containing at least isocyanurate structures based on 1,5-diisocyanatopentane or isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane.

[0101] Polyisocyanate mixture and further objects of the invention:

[0102] The polyisocyanate mixtures according to the invention are completely crystallization-stable and remain completely clear and free of turbidity even at 5°C and after four weeks of storage. Although they are preferably used solvent-free, they can also be diluted without turbidity if necessary with conventional solvents, for example the aforementioned isocyanate-inert solvents that may be used in the process according to the invention.

[0103] The polyisocyanate mixtures according to the invention represent valuable starting materials for the production of polyurethane plastics by the isocyanate polyaddition process. Therefore, a further subject of the invention is the use of the polyisocyanate mixture according to the invention or of the polyisocyanate mixture obtainable or produced, preferably produced directly, by the process according to the invention as a starting component in the production of polyurethane plastics, polyurea plastics and / or polythiourethane plastics, preferably for producing a coating on a substrate, wherein the substrate is preferably a mineral or metallic substrate, plastic or wood.

[0104] The polyisocyanate mixtures according to the invention are outstandingly suitable as curing agents for plastics. Therefore, a composition comprising either at least one polyisocyanate mixture according to the invention and at least one binder reactive toward isocyanate groups, or comprising at least one polyisocyanate mixture according to the invention, obtainable or prepared by the process according to the invention, and at least one binder reactive toward isocyanate groups, is a further subject of the present invention.

[0105] In a preferred embodiment, the composition according to the invention contains the at least one binder reactive toward isocyanate groups in a component 1) and the at least one polyisocyanate mixture according to the invention in a component 2) or the at least one polyisocyanate mixture obtainable or prepared by the process according to the invention in a component 2). Such a composition is also referred to below as a two-component system.

[0106] In this case or alternatively, it is further preferred that the at least one binder reactive towards isocyanate groups is a polyhydroxyl compound, a

[0107] Polyamine compound and / or a polythiol. Suitable polyhydroxyl compounds for the composition according to the invention are preferably polyester polyols, polyether polyols, polycarbonate polyols, polyester carbonate polyols, castor oil, blends of castor oil with ketone / formaldehyde condensates of the type described in GBPS 1 182 884 or EP-A 364 738, or any mixtures of such polyhydroxyl compounds.

[0108] Polyester polyols suitable as binders reactive towards isocyanate groups are, for example, those having an average molecular weight, calculable from functionality and hydroxyl number, of 200 to 3000, preferably 250 to 2500, with a hydroxyl group content of 1 to 21% by weight, preferably 2 to 18% by weight, as can be prepared in a manner known per se by reacting polyhydric alcohols with substoichiometric amounts of polybasic carboxylic acids, corresponding carboxylic anhydrides, corresponding polycarboxylic acid esters of lower alcohols or lactones.

[0109] Polyhydric alcohols suitable for producing these polyester polyols are, in particular, those in the molecular weight range 62 to 400, such as, for example, 1,2-ethanediol, 1,2- and 1,3-propanediol, the isomeric butanediols, pentanediols, hexanediols, heptanediols and octanediols, 1,2- and 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 4,4'-(1-methylethylidene)biscyclohexanol, 1,2,3-propanetriol, 1,1,1-trimethylolethane, 1,2,6-hexanetriol, 1,1,1-trimethylolpropane, 2,2-bis(hydroxymethyl)-1,3-propanediol or 1,3,5-tris(2-hydroxyethyl)isocyanurate.

[0110] The acids or acid derivatives used to produce the polyester polyols can be aliphatic, cycloaliphatic, and / or heteroaromatic in nature and can optionally be substituted, e.g., by halogen atoms, and / or unsaturated. Examples of suitable acids include polybasic carboxylic acids with a molecular weight range of 118 to 300 or their derivatives, such as succinic acid, adipic acid, sebacic acid, phthalic acid, isophthalic acid, trimellitic acid, phthalic anhydride, tetrahydrophthalic acid, maleic acid, maleic anhydride, dimeric and trimeric fatty acids, dimethyl terephthalate, and terephthalic acid bisglycol ester.

[0111] Any mixtures of these starting compounds mentioned as examples can also be used to produce the polyester polyols.

[0112] However, a type of polyester polyol preferably used as a polyhydroxyl compound is one that can be prepared in a conventional manner from lactones and simple polyhydric alcohols, such as those exemplified above, as starter molecules by ring opening. Suitable lactones for the preparation of these polyester polyols include, for example, β-propiolactone, γ-butyrolactone, γ- and δ-valerolactone, ε-caprolactone, 3,5,5- and 3,3,5-trimethylcaprolactone, or any mixtures of such lactones. Preparation generally takes place in the presence of catalysts such as Lewis or Brønsted acids, organic tin or titanium compounds at temperatures of 20 to 200°C, preferably 50 to 160°C.

[0113] Suitable binders reactive toward isocyanate groups include polyether polyols with an average molecular weight, calculated from functionality and hydroxyl number, of 200 to 6000, preferably 250 to 4000, and a hydroxyl group content of 0.6 to 34 wt. %, preferably 1 to 27 wt. %, as are obtainable in a conventional manner by alkoxylation of suitable starter molecules. To produce these polyether polyols, any polyhydric alcohols, for example those in the molecular weight range of 62 to 400, as described above for the production of polyester polyols, can be used as starter molecules.

[0114] Alkylene oxides suitable for the alkoxylation reaction are, in particular, ethylene oxide and propylene oxide, which can be used in any order or in a mixture in the alkoxylation reaction.

[0115] The polyether polyols preferably used as polyhydroxyl compounds for the compositions according to the invention are those whose alkylene oxide units consist of at least 80 mol%, but preferably exclusively, of propylene oxide units.

[0116] Suitable polyhydroxyl compounds of the polycarbonate type which are reactive towards isocyanate groups for the compositions according to the invention are, in particular, the polycarbonate diols which are known per se and which can be prepared, for example, by reacting dihydric alcohols, for example those exemplified above in the list of polyhydric alcohols in the molecular weight range 62 to 400, with diaryl carbonates, such as, for example, diphenyl carbonate, or phosgene.

[0117] Suitable polyhydroxyl compounds of the polyester carbonate type are in particular the diols containing ester groups and carbonate groups, which are known per se and which can be obtained, for example, according to the teaching of DE-AS 1 770 245 by reacting dihydric alcohols with lactones of the type mentioned above as examples, in particular s-caprolactone, and subsequently reacting the resulting polyester diols with diphenyl carbonate.

[0118] If desired, the polyhydroxyl compounds may further comprise up to 50% by weight, preferably up to 20% by weight, based on the total amount of polyhydroxyl compounds, of simple polyhydric alcohols, optionally containing ether oxygen, in the molecular weight range from 62 to 400, for the targeted adjustment of the viscosity of the compositions according to the invention. These are, for example, representatives of the type mentioned above in the list of polyhydric alcohols which are liquid at room temperature, in particular having a viscosity at 23 °C of less than 500 mPas, such as, for example, 1,2-ethanediol, 1,2- and 1,3-propanediol or 1,4-butanediol, but also simple ether alcohols, such as, for example, diethylene glycol or dipropylene glycol.

[0119] Particularly preferred polyhydroxy compounds for the compositions according to the invention are those that are in solvent-free form, have an average OH functionality of 2 to 4, and a viscosity at 23°C of less than 30,000 mPas, preferably less than 10,000 mPas. Solvent-free polyether polyols, castor oil, blends of castor oil with ketone / formaldehyde condensates, or any mixtures of such polyhydroxy compounds are very particularly preferred.

[0120] It is particularly preferred in the composition according to the invention that the at least one binder reactive towards isocyanate groups comprises at least one hydroxy-functional compound having a hydroxyl group content of > 2.0 wt.%, preferably > 3.0 wt.% and particularly preferably > 3.5 wt.%, based on the solids content of the binder reactive towards isocyanate groups.

[0121] Suitable binders which are reactive towards isocyanate groups for the composition according to the invention are also polyamine compounds, such as polyaspartic acid ester derivatives or polyamines whose amino groups are present in blocked form, such as polyketimines, polyaldimines or oxazolanes, and which, under the influence of moisture, release amino groups and, in the case of oxazolanes, also hydroxyl groups, which react by crosslinking with the isocyanate groups of the polyisocyanate mixtures according to the invention.

[0122] Preferred polyamine compounds for the compositions according to the invention are polyaspartic acid esters of the formula (V) in which

[0123] X represents an n-valent radical which is inert towards isocyanate groups and which is obtained by removing the primary amino groups from an organic amine having a molecular weight range of 60 to 6000 and having n primary aliphatically and / or cycloaliphatically bound amino groups, which optionally contains one or more heteroatoms and / or further functional groups which are reactive towards isocyanate groups and / or inert at temperatures up to 100 °C, R 1 and R 2 represent identical or different organic radicals with 1 to 18 carbon atoms and n represents an integer > 1.

[0124] The preparation of such polyaspartic acid esters is known in principle and can be carried out, for example, as described in EP-A 0 403 921, EP-A 0 689 881 or EP-A 0 816 326, by reaction of a component of the formula (VI) containing primary amino groups in which

[0125] X represents an n-valent radical which is inert towards isocyanate groups, as obtained by removing the primary amino groups from an organic amine of the molecular weight range 60 to 6000 having n primary aliphatically and / or cycloaliphatically bound amino groups, which optionally contains one or more heteroatoms and / or further functional groups which are reactive towards isocyanate groups and / or inert at temperatures up to 100 °C, and n represents an integer > 1, with fumaric acid esters and / or maleic acid esters of the formula (VII)

[0126] R 1 OOC - CH=CH-COOR 2 ( V ||), in which R 1 and R 2 represent identical or different organic radicals with 1 to 18 carbon atoms.

[0127] Suitable amines for the preparation of polyaspartic acid esters are, for example, difunctional amines, ie those of formula (VI) in which n is 2, such as ethylenediamine,

[0128] 1,2-Diaminopropane, 1,4-Diaminobutane, 1,5-Diaminopentane, 1,5-Diamino-2-methylpentane (Dytek® A from DuPont), 1,6-Diaminohexane, 2,5-Diamino-2,5-dimethylhexane, 2,2,4- and / or 2,4,4-Trimethyl-1,6-diaminohexane, 1,11-Diaminoundecane, 1,12-Diaminododecane, 1-Amino-3,3,5-trimethyl-5-aminomethylcyclohexane (IPDA), 1,3-Diamino-2- and / or -4-methylcyclohexane, Isopropyl-2,4- and / or 2,6-diaminocyclohexane, 1,3-Bis-(aminomethyl)-cyclohexane, 2,4'- and / or 4,4'-Diamino-dicyclohexylmethane, 3,3'-Dimethyl-4,4'-diamino-dicyclohexylmethane (Laromin® C 260; BASF SE, Ludwigshafen, DE), the isomeric diaminodicyclohexylmethanes containing a methyl group as core substituent (C-Monomethyl-diaminodicyclohexylmethane), 3(4)-Aminomethyl-1-methylcyclohexylamine and

[0129] 1,3-Bis-(aminomethyl)-benzene. Suitable tri- or higher-functional amines for preparing the polyaspartic acid esters are those of the formula (VI) in which n is an integer > 3, such as, for example, 4-aminomethyl-1,8-octanediamine, 2,2',2"-triaminotriethylamine, 1,3,5-tris-(aminomethyl)-2,4,6-triethylbenzene, tris-1,1,1-aminoethylethane, 1,2,3-triaminopropane, tris-(3-aminopropyl)-amine and N,N,N',N'-tetrakis-(2-aminoethyl)-ethylenediamine.

[0130] Suitable amines (VI) for the preparation of aspartic acid esters or polyaspartic acid esters are in principle also monoamines (n = 1) and diamines (n = 2) which contain further groups which are reactive towards isocyanates in the temperature range from 20 to 200°C, for example amino alcohols, such as 2-aminoethanol, the isomeric aminopropanols and -butanols, 3-amino-1,2-propanediol and 1,3-diamino-2-propanol.

[0131] Low molecular weight polyether polyamines with aliphatically bound primary amino groups, such as those sold under the name Jeffamin® (Huntsman Performance Products, The Woodlands, Texas, USA), are also in principle suitable amino components for the production of suitable polyaspartic acid esters.

[0132] However, preferred amino-functional reactants for the polyisocyanate mixtures according to the invention are polyaspartic acid esters of the formula (VI) in which n is 2, in particular aliphatic and / or cycloaliphatic diamines of the type mentioned above. Very particularly preferred polyaspartic acid esters are those based on 1,5-diamino-2-methylpentane, 2,4'- and / or 4,4'-diamino-dicyclohexylmethane and / or 3,3'-dimethyl-4,4'-diamino-dicyclohexylmethane.

[0133] In the production of aspartic acid esters or polyaspartic acid esters, fumaric acid diesters or maleic acid diesters of the formula (VII) are used, in which the radicals R 1 and R 2 represent identical or different radicals and are organic radicals having 1 to 18, preferably 1 to 9, particularly preferably 1 to 4, carbon atoms.

[0134] Preferably, maleic acid esters of formula (VII) are used, in which the radicals R 1 and R 2 represent identical or different radicals and denote a methyl, ethyl, n-butyl, or 2-ethylhexyl radical. Polyaspartic acid esters particularly preferred as reactants for the polyisocyanate mixtures according to the invention are those prepared using diethyl maleate and having a fumaric acid diester content of less than 0.1% by weight.

[0135] The preparation of the aspartic acid esters or polyaspartic acid esters can be carried out in solution, but is preferably carried out solvent-free. In both cases, an equimolar reaction of the amine (VI) with the fumaric acid diester and / or maleic acid diester (VII) is preferably carried out. To specifically vary application properties, the equivalence ratio of maleic acid ester and / or fumaric acid ester (VII) to amino groups of component (VI) can be varied from 1.2:1 to 1:2. If mixtures of aspartic acid esters or polyaspartic acid esters are used in the coating composition according to the invention, the polyaspartic acid esters can be prepared separately or in a single reaction vessel.

[0136] The composition according to the invention may optionally also contain, as binders reactive towards isocyanate groups, compounds which contain at least two structural elements of the formula (VIII) These compounds, which are referred to as polyaldimines or polyketimines in the context of the present invention, generally have molecular weights of 112 to 6500, preferably of 140 to 2500, particularly preferably of 140 to 458.

[0137] The preferred polyaldimines or polyketimines optionally used in the compositions according to the invention include compounds of the formula (IX) in which

[0138] R 3 and R 4 represent identical or different radicals and denote hydrogen or inert organic radicals, such as hydrocarbon radicals having up to 8 carbon atoms, in particular alkyl radicals having 1 to 8 carbon atoms, and where the radicals R 5 and R 6 may also form a 5- or 6-membered cycloaliphatic ring together with the carbon atom, with the proviso that the radicals R 3 and R 4do not simultaneously represent hydrogen, and

[0139] X has the meaning given above in the description of the amines and m is an integer > 2.

[0140] Particularly preferred are compounds of formula (IX) in which all radicals R 3 represent hydrogen, the radicals R 4 represent hydrocarbon radicals with up to 8 carbon atoms and m = 2. The aldehydes or ketones used for the preparation of the polyaldimines or polyketimines correspond to those of the formula (X) in which R 3 and R 4 have the meaning given above and preferably have a molecular weight of 58 to 198 (ketones) or 44 to 128 (aldehydes).

[0141] Suitable aldehydes for preparing the polyaldimines optionally used in the compositions according to the invention are, for example, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, trimethylacetate aldehyde, 2,2-dimethylpropanal, 2-ethylhexanal, 3-cyclohexane-1-carboxaldehyde, hexanal, heptanal, octanal, valeraldehyde, benzaldehyde, tetrahydrobenzaldehyde, hexahydrobenzaldehyde, propargylaldehyde, p-toluylaldehyde, phenylethanal, 2-methylpentanal, 3-methylpentanal, 4-methylpentanal and / or sorbaldehyde.

[0142] Particularly preferred are n-butyraldehyde, isobutyraldehyde, trimethylacetaldehyde, 2-ethylhexanal and hexahydrobenzaldehyde.

[0143] Suitable ketones for preparing the polyketimines optionally used in the compositions according to the invention are, for example, acetone, methyl ethyl ketone, methyl propyl ketone, methyl isopropyl ketone, methyl butyl ketone, methyl isobutyl ketone, methyl tert-butyl ketone, methyl n-amyl ketone, methyl isoamyl ketone, methyl heptyl ketone, methyl undecyl ketone, diethyl ketone, ethyl butyl ketone, ethyl amyl ketone, diisopropyl ketone, diisobutyl ketone, cyclohexanone, cyclopentanone, methylcyclohexanone, isophorone, 5-methyl-3-heptanone, 1-phenyl-2-propanone, acetophenone, methyl nonyl ketone, dinonyl ketone and / or 3,3,5-trimethylcyclohexanone.

[0144] Particularly preferred are cyclopentanone, cyclohexanone, methylcyclopentanone, methylcyclohexanone, 3,3,5-trimethylcyclopentanone, cyclobutanone, methylcyclobutanone, acetone, methyl ethyl ketone, methyl isobutyl ketone.

[0145] Of course, any mixtures of different ketones or aldehydes and also mixtures of ketones with aldehydes can be used to achieve special properties.

[0146] The polyamines used to prepare the polyaldimines or polyketimines optionally used in the compositions according to the invention as reactants for the polyisocyanate mixtures according to the invention are the amines of the general formula (VI) already explicitly described above in connection with the preparation of the polyaspartic acid esters, in which n is an integer > 2, or any mixtures of such polyamines. The preferred polyamine for preparing the polyaldimines or polyketimines is 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane (IPDA). Very particular preference is given to the polyaldimine obtainable by reacting IPDA with isobutyraldehyde.

[0147] The polyaldimines or polyketimines are prepared by conventional methods by reacting the starting components while maintaining a stoichiometric ratio of amino groups to aldehyde or keto groups of 1:1 to 1:1.5. If necessary, catalytic amounts of acidic substances such as p-toluenesulfonic acid, hydrogen chloride, sulfuric acid, or aluminum chloride can be used to accelerate the reaction.

[0148] The reaction generally takes place within a temperature range of 20 to 180°C, optionally using an entraining agent (e.g., toluene, xylene, cyclohexane, and gentian) to remove the water of reaction, until the calculated amount of water (1 mol of water per mol of primary amino group) has been eliminated or until no more water is eliminated. The phases are then separated, or the entraining agent and any unreacted reactants are removed by distillation. The products thus obtained can be used in the compositions of the invention without further purification.

[0149] The polyisocyanate mixtures according to the invention can also be combined in the compositions according to the invention with compounds which have at least one thiol group.

[0150] These are, for example, the polythiols known from EP-A 3 872 108, such as simple alkanethiols, polythiols containing thioether groups, polyetherthiols, polyesterthiols, aromatic thio compounds and / or mercapto alcohols.

[0151] In a further preferred embodiment, the composition according to the invention is a coating composition which can optionally contain auxiliaries and additives customary in coating technology, such as, for example, fillers, pigments, plasticizers, curing catalysts, UV protectants, antioxidants, microbicides, algicides, water scavengers, thixotropic agents, wetting agents, flow control agents, matting agents, anti-slip agents, deaerating agents or extenders. The auxiliaries and additives are mixed into component 1) and / or 2) depending on the requirements of the problems to be solved by the application of the coating and their compatibility. For example, water-containing or strongly alkaline additives should not be mixed into component 2) but rather into component 1). Suitable fillers are, for example, stone or plastic granules, glass beads, sand or cork, which may optionally be added in amounts of up to 800 wt.-% based on the composition according to the invention consisting of the individual components 1) and 2).

[0152] Suitable pigments include, for example, titanium dioxide, zinc oxide, iron oxides, chromium oxides, and carbon black. A detailed overview of pigments for paints is provided in "Textbook of Paints and Coatings, Volume 5: Pigments, Fillers, and Colorimetry," H. Kittel, J. Spille, S. Hirzel Verlag GmbH, 2002. The pigments mentioned as examples can be used, if at all, in amounts of up to 100 wt.% based on the composition according to the invention consisting of the individual components 1) and 2).

[0153] Plasticizers can also be used to adjust the viscosity of the ready-to-use coating compositions. Suitable examples include phthalic, adipic, or phosphoric esters of C4-C1g-alkanols and / or vinyl esters of alkarylsulfonic acids, which, if used at all, are used in amounts of up to 30% by weight, based on the composition according to the invention consisting of the individual components 1) and 2).

[0154] Other auxiliaries and additives optionally used in the coating compositions according to the invention include, for example, UV protectants, antioxidants, microbicides, algicides, water scavengers, thixotropic agents, wetting agents, leveling agents, matting agents, anti-slip agents, deaerating agents, or extenders. Such auxiliaries and additives are described, for example, in "Textbook of Paints and Coatings Volume 4: Solvents, Plasticizers and Additives," H. Kittel, M. Ortelt, S. Hirzel Verlag GmbH, 2007. Desiccants acting as water scavengers are described in more detail, for example, in "Kunststoff Handbuch 7, Polyurethane," Carl-Hanser-Verlag, Munich - Vienna, 1983, p. 545. The total amount of such further auxiliaries and additives is generally 0 to 25 wt. %, based on the inventive composition consisting of the individual components 1) and 2).

[0155] The coating compositions according to the invention are prepared by mixing the individual components, for example using the known dissolvers or vacuum dissolvers, which are often preferred in order to achieve extensive degassing of the coating agents.

[0156] The coating compositions according to the invention are preferably used solvent-free. If necessary, however, they can of course also be diluted with suitable solvents that are inert toward the reactive groups present in the composition, for example to reduce viscosity. Suitable solvents for this purpose are, in particular, the conventional paint solvents, which, as described above, can also be used in the process according to the invention if necessary.

[0157] In general, the coating materials formulated with the polyisocyanate mixtures according to the invention possess good coating properties even when dried at room temperature. However, the compositions according to the invention can also be dried under less demanding conditions at elevated temperatures or by baking at temperatures up to 260 °C.

[0158] To control the curing rate, suitable catalysts can be used in the formulation of the coating agents, for example the catalysts commonly used in isocyanate chemistry, such as tertiary amines such as triethylamine, pyridine, methylpyridine, benzyldimethylamine, N,N-endoethylenepiperazine, N-methylpiperidine, pentamethyldiethylenetriamine, N,N-dimethylaminocyclohexane, N,N'-dimethylpiperazine or metal salts such as iron(III) chloride, zinc chloride, zinc 2-ethylcaproate, tin(II) octanoate, tin(II) ethylcaproate, dibutyltin(IV) dilaurate, bismuth(III) 2-ethylhexanoate, bismuth(III) octoate or molybdenum glycolate.

[0159] The polyisocyanate mixtures according to the invention are also suitable as crosslinking components for binders dissolved or dispersed in water, or for binder components containing isocyanate-reactive groups, particularly alcoholic hydroxyl groups, in the production of aqueous two-component polyurethane systems. Due to their low viscosity, they can be used either as such, i.e., in hydrophobic form, or in hydrophilically modified form by known processes, e.g., according to EP-B 0 540 985, EP-B 0 959 087, or EP-B 1 287 052.

[0160] According to a preferred embodiment, the isocyanate groups of the polyisocyanate mixtures according to the invention can be partially or completely reacted with at least one blocking agent.

[0161] These blocking agents are, in particular, blocking agents known per se from polyurethane chemistry, such as, for example, malonic acid diethyl ester, acetoacetic ester, activated cyclic ketones, such as, for example, cyclopentanone-2-carboxymethyl ester and -carboxyethyl ester, acetone oxime, butanone oxime, s-caprolactam, 3,5-dimethylpyrazole, 1,2,4-triazole, dimethyl-1,2,4-triazole, imidazole, diisopropylamine, benzyl-tert-butylamine or any mixtures of these blocking agents.

[0162] In blocked form, the polyisocyanate mixtures according to the invention can also be used in combination with the above-mentioned coating binders or coating binder components in one-component polyurethane stoving systems. In all coating combinations, the polyisocyanate mixtures according to the invention and the reactant are present in amounts such that 0.5 to 3, preferably 0.6 to 2.0, particularly preferably 0.8 to 1.6, optionally blocked, isocyanate-reactive groups are present for each optionally blocked isocyanate group. If desired, the polyisocyanate mixtures according to the invention can also be admixed in minor amounts to non-functional coating binders to achieve very specific properties, for example, as an additive to improve adhesion.

[0163] Any substrates can be considered as substrates for the coatings formulated using the polyisocyanate mixtures according to the invention,

[0164] The invention further provides a process for producing a coating on a substrate, comprising the following steps: a) providing an optionally pretreated substrate; b) applying at least one composition according to the invention; and c) curing the composition, optionally with the addition of heat.

[0165] Further objects of the invention are thus coating compositions containing the polyisocyanate mixtures according to the invention, as well as a coated substrate, obtainable or produced by the process according to the invention,

[0166] The two-component polyurethane, polyurea, and polythiourethane coating compositions according to the invention are suitable for coating any substrate, such as metal, wood, glass, stone, ceramic materials, concrete, rigid and flexible plastics, textiles, leather, and paper, which can optionally be provided with conventional primers prior to coating. They can be applied, particularly in solvent-free form, in high layer thicknesses of, for example, up to 5 mm using conventional methods such as spraying, rolling, doctor blades, or spatulas.

[0167] They cure even at room temperature without bubbles to form light- and weather-resistant paint films that are characterized by high hardness and excellent abrasion resistance while also exhibiting high elasticity and tear resistance.

[0168] The coating compositions according to the invention are particularly suitable for coating mineral substrates, for example for producing highly abrasion-resistant floor or balcony coatings, as liquid plastic for roof sealing or concrete renovation or also as binders for decorative gravel mortar.

[0169] In addition to the described use for producing coatings on any substrates, the coating compositions according to the invention can also be used very advantageously as solvent-free two-component polyurethane, polyurea and / or polythiourethane coating compositions, for example, for producing lightfast casting compounds.

[0170] The coating compositions according to the invention can be present, for example, as a two-component system comprising a crosslinker component containing at least one polyisocyanate mixture according to the invention and a binder component containing at least one paint binder or a paint binder component containing groups reactive toward isocyanate groups, or as a one-component system containing at least one polyisocyanate mixture according to the invention in blocked form. Such systems are also subject of the present invention.

[0171] In addition to the preferred use as crosslinking components for solvent-based or aqueous and preferably solvent-free two-component polyurethane, polyurea and / or polythiourethane coatings, the polyisocyanate mixtures according to the invention are outstandingly suitable as crosslinking agents for solvent-free or solvent-based adhesive binders or aqueous dispersion adhesives, or also as a building component for the production of lightfast compact or foamed polyurethane moldings.

[0172] Therefore, a further subject matter of the invention are polyurethanes, polyureas and / or polythiourethanes, obtainable or prepared by reacting at least one polyisocyanate mixture according to the invention with at least one hydroxy-, amino- and / or thiofunctional component.

[0173] The features identified as preferred for the process according to the invention or the polyisocyanate mixture according to the invention are also preferred for the further subject matters of the invention.

[0174] The following examples serve to illustrate the present invention, but should in no way be understood as a limitation of the scope of protection.

[0175] Examples

[0176] Unless otherwise stated, all percentages are based on weight.

[0177] The NCO content was determined titrimetrically according to DIN EN ISO 11909:2007-05.

[0178] All viscosity measurements were carried out using a Physica MCR 51 rheometer from Anton Paar Germany GmbH (DE) according to DIN EN ISO 3219:1994-10 at a shear rate of 250 s' 1 .

[0179] The residual monomer contents were measured according to DIN EN ISO 10283:2007-11 using gas chromatography with an internal standard.

[0180] The sodium and potassium cation levels were determined by inductively coupled plasma atomic emission spectrometry (ICP-OES) according to DIN EN ISO 11885:2009-09 after microwave digestion. The detection limit for this method is <1 ppm.

[0181] The platinum-cobalt color number was measured spectrophotometrically according to DIN EN ISO 6271-2:2005-03 using a LICO 400 spectrophotometer from Lange, Germany.

[0182] The contents (mol-%) of the allophanate, urethane and optionally isocyanurate and / or uretdione structures present in the polyisocyanates according to the invention were determined from the integrals of proton-decoupled 13C NMR spectra (recorded on a Bruker DPX-400) are calculated and refer to the sum of allophanate, urethane, isocyanurate, and / or uretdione structures present. For PDI and HDI polyisocyanates dissolved in CDCh, the individual structural elements exhibit the following chemical shifts (in ppm): allophanate: 155.7 and 153.8; urethane: 156.3; isocyanurate: 148.4; uretdione: 157.1.

[0183] Shore hardness was measured according to DIN 53505 using a Zwick 3100 Shore hardness tester (Zwick, Germany).

[0184] The tear resistance of the resulting coatings was determined on free films according to DIN ISO 34-1. Elongation and stress at break were also determined on free films according to DIN EN ISO 527-1.

[0185] Output connections

[0186] Polyisocyanate M1)

[0187] 1234 g (8.0 mol) of PDI were initially charged at 95°C under dry nitrogen and with stirring, and 0.16 g of zinc(II)-2-ethyl-1-hexanoate was added as a catalyst. Over a period of approximately 45 minutes, 309 g (1.0 mol) of a statistically triethoxylated lauryl alcohol (OH number: 181.8 mg KOH / g, Na content: 28 mg / kg, K content: < 1 mg / kg) were added dropwise, with the temperature of the mixture rising to 100°C due to the exothermic reaction. The reaction mixture was then further stirred at 100°C until the NCO content had dropped to 35.6% after approximately 1 hour. The catalyst was deactivated by adding 0.16 g of orthophosphoric acid, and the unreacted monomeric PDI was separated in a thin-film evaporator at a temperature of 130°C and a pressure of 0.1 mbar. This yielded 723 g of a virtually colorless, clear polyisocyanate mixture with the following characteristics and composition:

[0188] NCO content: 14.1% monomeric PDI: 0.03%

[0189] Viscosity (23°C): 290 mPas

[0190] Color number (APHA): 21 Hazen

[0191] Composition: Allophanate: 70.3 mol-%

[0192] Urethane: 4.2 mol%

[0193] Isocyanurate: 24.9 mol%

[0194] Uretdione: 0.6 mol%

[0195] Polyisocyanate N1)

[0196] PDI polyisocyanate containing isocyanurate groups, prepared by catalytic trimerization of PDI according to the process described in WO 2016 / 146579 for polyisocyanate component A2). The reaction was deactivated at an NCO content of the crude mixture of 36.7% by adding an equimolar amount of dibutyl phosphate, based on the amount of catalyst used, and stirring for 30 minutes at 80°C. Unreacted PDI was then removed by thin-film distillation at a temperature of 140°C and a pressure of 0.5 mbar.

[0197] NCO content: 21.8% monomeric PDI: 0.09%

[0198] Viscosity (23 °C): 9850 mPas

[0199] Color number (Hazen): 34

[0200] Polyisocyanate N2)

[0201] HDI polyisocyanate containing isocyanurate groups, prepared by catalytic trimerization of HDI based on Example 11 of EP-A 330 966, with the modification that 2-ethylhexanol was used as the catalyst solvent instead of 2-ethyl-1,3-hexanediol, and the reaction was stopped at an NCO content of the crude mixture of 42.5% by adding dibutyl phosphate. Unreacted HDI was then separated by thin-film distillation at a temperature of 130°C and a pressure of 0.2 mbar. The product had the following characteristics and composition:

[0202] NCO content: 22.9% monomeric HDI: 0.08%

[0203] Viscosity (23°C): 1210 mPas

[0204] Color number (Hazen): 10

[0205] Polyisocyanate N3)

[0206] Polyisocyanate, prepared according to Comparative Example 2a of WO 2018 / 153801, by trimerization of HDI using a 20% solution of 5-azoniaspiro[4.5]decanium hydrogen difluoride in 2-ethylhexanol as catalyst, stopping the reaction at an NCO content of the crude mixture of 44.8% by adding an amount equivalent to the amount of catalyst of a 70% solution of dodecylbenzenesulfonic acid in isopropanol, and subsequently separating the unreacted HDI by thin-film distillation at a temperature of 130°C and a pressure of 0.2 mbar. The product had the following characteristics and composition:

[0207] NCO content: 23.5% monomeric HDI: 0.06%

[0208] Viscosity (23°C): 720 mPas

[0209] Color number (Hazen): 38

[0210] Polyol component 1

[0211] Mixture of 75 mol% castor oil and 25 mol% of a cyclohexanone-formaldehyde condensation product with a viscosity at 23 °C of approx. 3500 mPas and an OH content of 4.7%.

[0212] Polyol component 2

[0213] Polyether polyol produced by propoxylation of TMP with an average molecular weight of 450, a viscosity at 23 °C of approximately 600 mPas and an OH content of 11.7%.

[0214] Polyamine component 1

[0215] Polyaspartic acid ester, prepared according to EP-B 0 403 921 (Polyaspartic acid ester I)) by reacting 2 mol of diethyl maleate with 1 mol of 4,4'-diaminodicyclohexylmethane, with a viscosity at 23 °C of approximately 1000 mPas and an equivalent weight of 276 g / eq. (Preparation of polyisocyanate mixture 1)

[0216] 80 parts by weight of polyisocyanate M1) were homogeneously mixed with 20 parts by weight of polyisocyanate N1) at 50°C by stirring. After cooling to room temperature, a polyisocyanate mixture 1 according to the invention was obtained with the following characteristics:

[0217] NCO content: 15.6% monomeric PDI: 0.04%

[0218] Viscosity (23°C): 510 mPas

[0219] Color number (Hazen): 25

[0220] Example 2 (Preparation of polyisocyanate mixture 2)

[0221] 50 parts by weight of polyisocyanate M1) were mixed homogeneously with 50 parts by weight of polyisocyanate N1) at 50°C by stirring. After cooling to room temperature, a polyisocyanate mixture 2 according to the invention was obtained with the following characteristics:

[0222] NCO content: 18.0% monomeric PDI: 0.06%

[0223] Viscosity (23°C): 1300 mPas

[0224] Color number (Hazen): 28

[0225] (Production of polyisocyanate mixture 3)

[0226] 75 parts by weight of polyisocyanate M1) were mixed homogeneously with 25 parts by weight of polyisocyanate N1) at 50°C by stirring. After cooling to room temperature, a polyisocyanate mixture 3 according to the invention was obtained with the following characteristics:

[0227] NCO content: 16.0% monomeric PDI: 0.05%

[0228] Viscosity (23°C): 570 mPas

[0229] Color number (Hazen): 22

[0230] Example 4 (Preparation of polyisocyanate mixture 4)

[0231] 75 parts by weight of polyisocyanate M1) were mixed homogeneously with 25 parts by weight of polyisocyanate N3) at 50°C by stirring. After cooling to room temperature, a polyisocyanate mixture 4 according to the invention was obtained with the following characteristics:

[0232] NCO content: 16.5% monomeric PDI: 0.04%

[0233] Viscosity (23°C): 400 mPas

[0234] Color number (Hazen): 25

[0235] Example 5 (coating composition according to the invention, processing time)

[0236] 60.8 parts by weight of polyol component 1 and 39.2 parts by weight of polyisocyanate mixture 2 (corresponding to an equivalent ratio of NCO:OH = 1:1) were homogenized to form a clear coat using a DAC 150 FVZ speed mixer (Hauschild, Germany) for 1 minute at 3500 μl / min. The initial viscosity of the clear coat at 23 °C was 2310 mPas. To determine the processing time, the viscosity was measured again at intervals of 1 minute. After 20 minutes, the intrinsic viscosity of 10,000 mPas, above which application by roller is no longer possible, was exceeded.

[0237] Example 6 (Comparison, processing time)

[0238] 65.2 parts by weight of polyol component 1 and 34.8 parts by weight of polyisocyanate 1 (corresponding to an equivalent ratio of NCO:OH = 1:1) were homogenized to form a clear coat using a DAC 150 FVZ speed mixer (Hauschild, Germany) for 1 minute at 3500 ll / min. The initial viscosity of the clear coat at 23 °C was 4720 mPas. To determine the processing time, the viscosity was measured again at intervals of 1 minute. After 11 minutes, the intrinsic viscosity of 10,000 mPas, above which application by roller is no longer possible, was exceeded.

[0239] The comparison of Examples 5 and 6 shows that the processing time of the coating composition according to the invention (Example 5) at 23°C is almost twice as long as that of the comparison coating from Example 6.

[0240] Example 7 (coating composition and coating according to the invention)

[0241] From 32.6 parts by weight of polyol component 1, 38.0 parts by weight of barite EWG (Deutsche Barytindustrie, Bad Lauterberg, Germany), 0.01 part by weight of dioctyltin(IV) neodecanoate (TIB KAT 318, TIB Chemicals AG, Mannheim, Germany) as catalyst, 0.15 parts by weight of a commercially available defoamer TEGO AIREX 944 (Evonik Operations GmbH, Essen, Germany) as filler, 3.3 parts by weight of Finma-Sorb 430PR (Finma GmbH, Rosbach vor der Höhe, Germany) as desiccant, 0.8 parts by weight of Disperbyk 2205 (BYK-Chemie GmbH, Wesel, Germany) as dispersing additive and 0.8 parts by weight of Tioxide TR-81 (Huntsman Pigments Division, Billingham, UK), 0.06 parts by weight of Bayferrox 920, 0.03 parts by weight of Bayferrox 222, and 0.09 parts by weight of Bayferrox® 318 M (each from LANXESS Deutschland GmbH, Cologne, Germany) as pigments using a dissolver. Subsequently, 24.3 parts by weight of-parts of polyisocyanate mixture 1 (corresponding to an equivalent ratio of NCO:OH = 1:1) were added and mixed for 5 minutes in a dissolver. The resulting solvent-free coating composition according to the invention was poured onto a polypropylene plate and spread to a layer thickness of approximately 1 mm.

[0242] After 24 hours of curing at room temperature and subsequent three days of storage at 50°C, the coating was peeled off the substrate. The following properties were found on the free film:

[0243] Shore A / D hardness: 71 / 22

[0244] Tensile strength: 1.8 N / mm 2

[0245] Tear resistance: 2.4 N / mm

[0246] Example 8 (coating composition and coating according to the invention)

[0247] 78.2 parts by weight of the base coating described in Example 7 were mixed with 21.8 parts by weight of Polyisocyanate Mixture 2 (corresponding to an equivalent ratio of NCO:OH = 1:1) and mixed for 5 minutes in a dissolver. The resulting coating composition was applied to a polypropylene plate and cured as described in Example 7. The following properties were found on the free film:

[0248] Shore A / D hardness: 72 / 28

[0249] Tensile strength: 3.5 N / mm 2

[0250] Tear resistance: 3.4 N / mm

[0251] Example 9 (Comparison)

[0252] 81.3 parts by weight of the base coating described in Example 7 were mixed with 18.7 parts by weight of polyisocyanate N1) (corresponding to an equivalent ratio of NCO:OH = 1:1) and mixed for 5 minutes in a dissolver. The resulting coating composition was also applied to a polypropylene plate and cured as described above. The following properties were found for the free film:

[0253] Shore A / D hardness: 89 / 43

[0254] Tensile strength: 7.2 N / mm 2

[0255] Tear resistance: 8.2 N / mm

[0256] A comparison of Examples 7 to 9 shows that the coating compositions according to the invention according to Examples 7 and 8 result in films with lower Shore A / D hardness while still maintaining acceptable strengths for floor coatings, which translates into improved walking comfort. Example 10 (Coating composition and coating according to the invention)

[0257] From 26.1 parts by weight of polyol component 1 and 8.7 parts by weight of polyol component 2, 27.8 parts by weight of barite EWG (Deutsche Barytindustrie, Bad Lauterberg, DE), 0.02 parts by weight of dioctyltin(IV) neodecanoate (TIB KAT 318, TIB Chemicals AG, Mannheim, DE) as catalyst, 0.15 parts by weight of a commercially available defoamer TEGO AIREX 944 (Evonik Operations GmbH, Essen, DE) as filler, 3.5 parts by weight of Finma-Sorb 430PR (Finma GmbH, Rosbach vor der Höhe, DE) as desiccant, 0.3 parts by weight of Disperbyk2205 (BYK-Chemie GmbH, Wesel, DE) as dispersing additive and 2.1 parts by weight A solvent-free base coat was formulated using a dissolver from 0.06 parts by weight of Bayferrox 920, 0.03 parts by weight of Bayferrox 222 and 0.10 parts by weight of Bayferrox® 318 M (each from LANXESS Deutschland GmbH, Cologne, DE) as pigments.

[0258] Subsequently, 30.9 parts by weight of polyisocyanate mixture 2 (corresponding to an equivalent ratio of NCO:OH = 1:1) were added and mixed for 5 minutes in a dissolver. The resulting solvent-free coating composition according to the invention was applied to a polypropylene plate and cured as described in Example 7. The following properties were found for the free film:

[0259] Shore A / D hardness: 80 / 34

[0260] Tensile strength: 6.0 N / mm 2

[0261] Tear resistance: 6.0 N / mm

[0262] Example 11 (Comparison)

[0263] 74.0 parts by weight of the base coating described in Example 10 were mixed with 26.0 parts by weight of polyisocyanate N2) (corresponding to an equivalent ratio of NCO:OH = 1:1) and mixed for 5 minutes in a dissolver. The resulting coating composition was applied to a polypropylene plate and cured as described in Example 7. The following properties were found for the free film:

[0264] Shore A / D hardness: 90 / 46

[0265] Tensile strength: 11.1 N / mm 2

[0266] Tear resistance: 17.2 N / mm

[0267] A comparison of Examples 10 and 11 shows that the inventive polyisocyanate mixture 2 based on PDI results in coatings with lower Shore A / D hardnesses compared to an HDI polyisocyanate of similar viscosity (Polyisocyanate N2), which translates into improved walking comfort, particularly when used as a floor coating. Example 12 (inventive coating composition, processing time, and coating)

[0268] 54.2 parts by weight of polyamine component 1 and 45.8 parts by weight of polyisocyanate mixture 2 (corresponding to an equivalent ratio of NCO:NH = 1:1) were homogenized to form a clearcoat using a SpeedMixer DAC 150 FVZ (Hauschild, Germany) for 1 minute at 3500 ll / min. The initial viscosity of the clearcoat at 23 °C was 2200 mPas. To determine the processing time, the viscosity was measured again at intervals of 1 minute. After 22 minutes, the intrinsic viscosity of 10,000 mPas, above which application by roller is no longer possible, was exceeded.

[0269] The resulting clear coat was applied to a polypropylene plate immediately after preparation and cured as described in Example 7. The following properties were found on the smooth, free film:

[0270] Shore A / D hardness: 97 / 72

[0271] Tensile strength: 40 N / mm 2

[0272] Tear resistance: 3.4 N / mm

[0273] Example 13 (Comparison, processing time)

[0274] 58.9 parts by weight of polyamine component 1 and 41.1 parts by weight of polyisocyanate N1 (corresponding to an equivalent ratio of NCO:NH = 1:1) were homogenized to form a clear coat using a DAC 150 FVZ speed mixer (Hauschild, Germany) for 1 minute at 3500 ll / min. The initial viscosity of the clear coat at 23 °C was 5860 mPas. To determine the processing time, the viscosity was measured again at intervals of 1 minute. After 5 minutes, the intrinsic viscosity of 10000 mPas, above which application by roller is no longer possible, was exceeded.

[0275] Due to the very short processing time, it was not possible to produce a smooth, free film.

[0276] The comparison of Examples 12 and 13 shows that the processing time of the coating composition according to the invention (Example 12) at 23°C is more than four times longer than that of the comparative coating from Example 13.

Claims

1. Polyisocyanate mixture containing at least one polyisocyanate M) of the general formula (I) in which R represents a linear or branched, saturated or unsaturated aliphatic and / or saturated or unsaturated cycloaliphatic radical having (6 to 22) - p carbon atoms, each of which may optionally be substituted, R' and R" independently of one another represent hydrogen or an aliphatic radical having 1 to 10 carbon atoms, where at least one of the radicals R' and R" represents hydrogen, n represents an integer from 1 to 12, m represents an integer from 1 to 10 and p represents 0 or 1 and at least one polyisocyanate N) different from polyisocyanate M) having a uretdione, isocyanurate, iminooxadiazinedione, urethane, allophanate, biuret and / or oxadiazinetrione structure which carries aliphatically, cycloaliphatically, araliphatically and / or aromatically bound isocyanate groups, where the polyisocyanates are present in a weight ratio of M) to N) of 40:60 to 90:

10.

2. Polyisocyanate mixture according to claim 1, characterized in that the polyisocyanates M) and N) are present in a weight ratio to one another of 40:60 to 85:15 and preferably of 50:50 to 80:

20.

3. Polyisocyanate mixture according to claim 1 or 2, characterized in that it has an NCO content determined according to DIN EN ISO 11909:2007-05 of 6.8 to 19.6 wt.%, preferably 6.8 to 19.2 wt.%, particularly preferably 7.0 to 18.8 wt.%.

4. Polyisocyanate mixture according to one of claims 1 to 3, characterized in that the polyisocyanate N) has aliphatically, araliphatically and / or cycloaliphatically bound isocyanate groups, preferably based on 1,5-diisocyanatopentane, 1,6-diisocyanatohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, 1,3-bis(isocyanatomethyl)benzene, bis- (isocyanatomethyl)norbornane and / or 4,4'-diisocyanatodicyclohexylmethane and particularly preferably at least isocyanurate structures based on 1,5-diisocyanatopentane, 1,6-diisocyanatohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, 1,3-bis(isocyanatomethyl)benzene, bis- (isocyanatomethyl)norbornane and / or 4,4'-diisocyanatodicyclohexylmethane and very particularly preferably contains isocyanurate structures based on 1,5-diisocyanatopentane, 1,6-diisocyanatohexane and / or 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane.

5. Polyisocyanate mixture according to one of claims 1 to 4 having a shear rate of 250 s according to DIN EN ISO 3219:1994-10 -1 measured viscosity at 23°C of less than 3000 mPas, preferably less than 2000 mPas and particularly preferably less than 1500 mPas.

6. A process for the preparation of a polyisocyanate mixture, characterized in that at least one polyisocyanate M) of the general formula (I) in which R represents a linear or branched, saturated or unsaturated aliphatic and / or saturated or unsaturated cycloaliphatic radical having (6 to 22) - p carbon atoms, each of which may optionally be substituted, R' and R" independently of one another represent hydrogen or an aliphatic radical having 1 to 10 carbon atoms, where at least one of the radicals R' and R" represents hydrogen, n represents an integer from 1 to 12, m represents an integer from 1 to 10 and p represents 0 or 1 with at least one polyisocyanate N) different from polyisocyanate M) having a uretdione, isocyanurate, iminooxadiazinedione, urethane, allophanate, biuret and / or oxadiazinetrione structure which carries aliphatically, cycloaliphatically, araliphatically and / or aromatically bound isocyanate groups, so that the polyisocyanates M) and N) are present in a weight ratio to one another of 40:60 to 90:10, preferably of 40:60 to 85:15 and particularly preferably of 50:50 to 80:

20.

7. Use of the polyisocyanate mixture according to one of claims 1 to 5 or of the polyisocyanate mixture obtainable or produced, preferably directly produced, by the process according to claim 6 as a starting component in the production of polyurethane plastics, polyurea plastics and / or polythiourethane plastics.

8. Composition comprising either at least one polyisocyanate mixture according to one of claims 1 to 5 and at least one binder reactive towards isocyanate groups or comprising at least one polyisocyanate mixture obtainable or prepared by a process according to claim 6 and at least one binder reactive towards isocyanate groups.

9. Composition according to claim 8, characterized in that it contains the at least one binder reactive towards isocyanate groups in a component 1) and the at least one polyisocyanate mixture according to one of claims 1 to 5 in a component 2) or the at least one polyisocyanate mixture, obtainable or produced by a process according to claim 6, in a component 2) and / or that the at least one binder reactive towards isocyanate groups is a polyhydroxyl compound, preferably a polyester polyol, polyether polyol, polycarbonate polyol, castor oil or a mixture of castor oil with ketone / formaldehyde condensates and particularly preferably a solvent-free polyether polyol, castor oil, mixtures of castor oil with ketone / formaldehyde condensates or any mixtures of the aforementioned.

10. Composition according to claim 8 or 9, characterized in that the at least one binder reactive towards isocyanate groups comprises at least one polyhydroxyl compound having a hydroxyl group content of > 2.0 wt.%, preferably > 3.0 wt.% and particularly preferably > 3.5 wt.%, based on the solids content of the binder reactive towards isocyanate groups.

11. Composition according to claim 8, characterized in that it contains the at least one binder reactive towards isocyanate groups in a component 1) and the at least one polyisocyanate mixture according to one of claims 1 to 5 in a component 2) or the at least one polyisocyanate mixture obtainable or prepared by a process according to claim 6 in a component 2) and / or that the at least one binder reactive towards isocyanate groups is a polyamine compound, preferably a polyaspartic acid ester of the formula (V) (V) is in which X represents an n-valent radical which is inert towards isocyanate groups, as obtained by removing the primary amino groups from an organic amine of the molecular weight range 60 to 6000 having n primary aliphatically and / or cycloaliphatically bound amino groups, which optionally contains one or more heteroatoms and / or further functional groups which are reactive towards isocyanate groups and / or inert at temperatures up to 100°C, R 1 and R 2 represent identical or different organic radicals having 1 to 18 carbon atoms and n represents an integer > 1. and particularly preferably a polyaspartic acid ester based on 1,5-diamino-2-methylpentane, 2,4'- and / or 4,4'-diaminodicyclohexylmethane and / or 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane and diethyl maleate, which has a fumaric acid diester content of less than 0.1% by weight.

12. Composition according to one of claims 8 to 11, characterized in that it is a coating composition which optionally contains one or more auxiliaries and additives.

13. A method for producing a coating on a substrate, comprising the following steps: a) providing an optionally pretreated substrate; b) applying at least one composition according to one of claims 8 to 12; c) curing the composition, optionally with the addition of heat.

14. A process for producing a coating according to claim 13, characterized in that the coating is a floor or balcony coating or a roof waterproofing.

15. A coated substrate obtainable or produced by a process according to one of the Claims 13 and 14, wherein the optionally pretreated substrate is preferably a mineral or metallic substrate, plastic or wood and is preferably a mineral substrate.

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