Polyisocyanate mixtures

Abstract

The invention relates to polyisocyanate mixtures, to a method for the production thereof and to the use thereof as starting components in the production of polyurethane plastics. The invention further relates to a coating composition containing said polyisocyanate mixture and to a substrate coated with said coating composition.

Description

[0001] The present invention relates to polyisocyanate mixtures and processes for their production. The present invention further relates to the use of said polyisocyanate mixtures, coating compositions comprising said polyisocyanate mixtures and substrates coated with said coating compositions.

[0002] Two-component polyurethane coatings (2K-PUR) have become important for many different applications due to their excellent technical properties. The crosslinker component for lightfast, non-yellowing 2K-PUR coatings and coatings is usually a polyisocyanate based on linear aliphatic or cycloaliphatic diisocyanates.

[0003] At present, polyisocyanates based on 1,6-hexane diisocyanate (hereinafter also referred to as HDI) are used in most applications of 2K-PUR coatings. Even at low temperatures, these give elastic coatings with good resistance to chemical and mechanical stress.

[0004] In recent years, the trend towards more sustainable products has also led to an increased demand for bio-based raw materials in the polyurethane field. This is the reason for the development of polyisocyanate crosslinkers based on 1,5-pentane diisocyanate (hereinafter also referred to as PDI) obtainable from biomass (see, for example, EP-A 3271432 and WO 2016 / 169810). PUR coatings and adhesives produced using bio-based PDI polyisocyanates are similar in terms of property level to those crosslinked with comparable petrochemical-based HDI polyisocyanates and are even superior to these in some application areas.

[0005] However, a serious disadvantage of PDI polyisocyanates is that, compared to the corresponding HDI derivatives, they exhibit higher viscosities at comparable oligomer distributions (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 a larger amount of organic solvents. However, precisely in sustainable coating and adhesive systems, it is desirable for the proportion of volatile organic components to be as low as possible.

[0006] US2012 / 0016073 describes a process for producing a low-viscosity urethane polyisocyanate based on a monohydric alcohol containing ether or polyether groups, which can be used as a reactive diluent for higher-viscosity polyisocyanates. Polymeric methylene diisocyanates having 2 to 6 methylene units are generally mentioned as suitable starting diisocyanates for this process, where HDI is the preferred starting diisocyanate. The production of this HDI urethane polyisocyanate mandatorily requires a complex catalyst system, which consists of a bismuth compound, preferably bismuth tricarboxylate, and alkali metal salts and alkaline earth metal salts as cocatalysts. However, bismuth catalysts have the common drawback that, during long-term storage, especially when exposed to sunlight, they decompose, which usually leads to brown discoloration in the polyisocyanate or even the precipitation of black particles (D. Guhl, FAPU 49, 30–33 (2008), DOI: 10-1386-08-EPJ-2-2008-d.indd).

[0007] In Polymers 2021, 13, 1255 (DOI: https: / / doi.org / 10.3390 / polym13081255), Caillol et al. described a commercial product Tolonate from Vencorex, which is produced as a partially bio-based polyisocyanate with a urethane structure based on HDI and ethoxylated palmitic acid TM XFLO 100 as a constituent component of thermosetting polyurethanes. The above-mentioned drawbacks apply to the production of this product.

[0008] Furthermore, in the case of HDI urethanes, even low residual amounts of carbamate structures that may still be present due to incomplete urethanization can also cause turbidity in the product.

[0009] The prior art also does not describe any hint regarding the possible use of PDI to produce the corresponding urethanes.

[0010] Therefore, there is still a need to provide a low-viscosity urethane polyisocyanate that remains completely clear and free of turbidity even during long-term storage, regardless of the catalyst used and regardless of the residual carbamate content.

[0011] The object of the present invention is to provide a low-viscosity urethane polyisocyanate that remains completely clear and free of turbidity even during long-term storage, regardless of the catalyst used and regardless of the residual carbamate content.

[0012] In view of this need, the present invention provides a polyisocyanate mixture containing at least one polyisocyanate of general formula (I)

[0013]

[0014] wherein

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

[0016] R' and R" independently of one another represent hydrogen or an aliphatic group having 1 to 10 carbon atoms, where at least one of the groups R' and R" represents hydrogen,

[0017] n is an integer from 1 to 12,

[0018] m is an integer from 1 to 10, and

[0019] p is 0 or 1.

[0020] The subject of the present invention is also a process for producing a polyisocyanate mixture according to the invention by reacting the following components,

[0021] A) a diisocyanate component containing at least 1,5-pentane diisocyanate with

[0022] B) at least one alcohol of the general formula (II)

[0023]

[0024] wherein

[0025] R represents a straight-chain or branched, saturated or unsaturated aliphatic group and / or a saturated or unsaturated cycloaliphatic group having (6 to 22)-p carbon atoms, which is optionally substituted in each case,

[0026] R' and R" independently of one another represent hydrogen or an aliphatic group having 1 to 10 carbon atoms, where at least one of the groups R' and R" represents hydrogen,

[0027] m is an integer from 1 to 10, and

[0028] p is 0 or 1.

[0029] It has now surprisingly been found that PDI can be very easily converted into a low-viscosity, light-colored urethane polyisocyanate with ethoxylated fatty alcohols and / or fatty acids, even when using known urethanization catalysts such as zinc or zirconium catalysts. A particular advantage of using PDI lies in the fact that, compared to similarly produced HDI derivatives, PDI urethane polyisocyanates have significantly higher crystallization stability even in the case of incomplete urethanization, and the PDI polyisocyanates according to the invention remain completely clear and free of turbidity even at higher residual carbamate contents.

[0030] According to the invention, the terms "comprising" and "containing" are preferably understood to mean "consisting essentially of", and particularly preferably "consisting of". Further embodiments mentioned in the claims and the description can be combined as required, provided that the context does not clearly indicate the contrary.

[0031] As used herein, "at least one" means 1 or more, for example 2, 3, 4, 5, 6, 7, 8, 9 or more. With regard to the components of the compounds described herein, this value does not refer to the absolute number of molecules, but to the nature of the components. "At least one polyisocyanate" is thus understood to mean, for example, that it can contain only one type of polyisocyanate or more than one different type of polyisocyanate, rather than specifying the amounts of the individual compounds.

[0032] In the present context, the polyisocyanate mixture according to the invention containing at least one polyisocyanate of the general formula (I) is understood to mean that it generally contains not only the compound of the general formula (I) where n = 1, but also one or more compounds of the formula (I) where n = 2 to 12, which are preferably formed from PDI and an alcohol of the general formula (II), and can contain and preferably contain other oligomers, such as PDI isocyanurates, which are usually based on PDI.

[0033] Particularly preferably, the polyisocyanate mixture according to the invention contains a proportion of urethane structure greater than 60 mol%, preferably greater than 65 mol%, particularly preferably greater than 70 mol%, and even more preferably greater than 75 mol% as determined by NMR spectroscopy, based on the total molar proportion of urethane, isocyanurate, carbamate and uretidione structures.

[0034] The numerical values given herein without decimal places refer in each case to the complete value given with one decimal place. Thus, for example, "99%" represents "99.0%".

[0035] Numerical ranges given in the format "x to y" include the stated values. If multiple preferred numerical ranges are given in this format, it is understood that all ranges obtained by combination of the various endpoints are also included.

[0036] The term "aliphatic" is defined herein to mean a saturated or unsaturated non-aromatic hydrocarbon group.

[0037] The term "araliphatic" is defined herein to mean an aliphatic hydrocarbon group that is saturated or unsaturated and has at least one aromatic substituent.

[0038] The term "alicyclic" or "cycloaliphatic" is defined herein to mean a non-aromatic optionally substituted carbocyclic or heterocyclic compound or unit (e.g., cycloalkane, cycloalkene or oxacycloalkane, thioxacycloalkane, azacycloalkane or thiazacycloalkane). Specific examples are cyclohexyl, cyclopentyl and their N- or O-heterocyclic derivatives, such as pyrimidine, pyrazine, tetrahydropyran or tetrahydrofuran.

[0039] Where a group or compound is disclosed as "optionally substituted" or "substituted", suitable substituents are -F, -Cl, -Br, -I, -OH, -OCH3, -OCH2CH3, -O-isopropyl or -O-n-propyl, -OCF3, -CF3, -S-C 1-6 -alkyl and / or (optionally via a side heteroatom) a straight-chain or branched aliphatic and / or alicyclic structural unit having 1 to 12 carbon atoms, which in each case serves as a replacement for the carbon-bonded hydrogen atoms of the corresponding molecule. Preferred substituents are halogen (especially -F, -Cl), C 1-6 alkoxy (especially methoxy and ethoxy), hydroxy, trifluoromethyl and trifluoromethoxy, which in each case serve as a replacement for the carbon-bonded hydrogen atoms of the corresponding molecule.

[0040] In a first preferred embodiment, the polyisocyanate mixture according to the invention has an NCO content of from 6.0% to 18.0% by weight, preferably from 8.0% to 16.0% by weight, particularly preferably from 10.0% to 15.0% by weight, based on the total weight of the polyisocyanate mixture and / or a residual monomer content of less than 0.14% by weight, preferably less than 0.12% by weight, particularly preferably less than 0.10% by weight, based on the total weight of the polyisocyanate mixture, measured by gas chromatography using an internal standard in accordance with DIN EN ISO 10283:2007-11.

[0041] In another preferred embodiment, the polyisocyanate mixture according to the invention has a viscosity of less than 500 mPas, preferably less than 400 mPas, particularly preferably less than 300 mPas, measured at 23 °C at a shear rate of 250 s -1 in accordance with DIN EN ISO 3219:1994-10.

[0042] Preferably of the general formula (I)

[0043]

[0044] wherein

[0045] R represents a straight-chain or branched, saturated or unsaturated aliphatic group and / or a saturated or unsaturated alicyclic group having (8 to 20) -C, particularly preferably having (10 to 18) -C, very particularly preferably having (12 to 14) -C carbon atoms, which may optionally be substituted,

[0046] R' and R" each independently represent hydrogen or an aliphatic group having 1 to 10 carbon atoms, where at least one of the groups R' and R" represents hydrogen,

[0047] n is an integer from 1 to 12,

[0048] m is an integer from 1 to 7, particularly preferably an integer from 2 to 5, very particularly preferably an integer from 2 to 4, and

[0049] p is 0 or 1.

[0050] The diisocyanate component A) for producing the polyisocyanate mixture according to the invention contains at least 1,5-pentane diisocyanate (also referred to herein as pentamethylene diisocyanate or PDI), which can be obtained by various routes, for example by phosgenation in the liquid or gas phase or by a phosgene-free route, for example by thermal carbamate cleavage starting from 1,5-diaminopentane (which is preferably obtained by biotechnological means by decarboxylation of the naturally occurring amino acid lysine).

[0051] In addition to 1,5-pentane diisocyanate, other diisocyanates having aliphatic, cycloaliphatic, araliphatic and / or aromatic-bonded isocyanate groups can optionally be used jointly in the diisocyanate component A), which can likewise be obtained by phosgenation or by a phosgene-free route. These are in particular those in the molecular weight range from 140 to 400, such as 1,4-butane diisocyanate, 1,6-hexane diisocyanate (HDI), 2-methyl-1,5-pentane diisocyanate, 1,5-diisocyanato-2,2-dimethylpentane, 2,2,4- or 2,4,4-trimethyl-1,6-hexane diisocyanate, 1,10-decane diisocyanate, 1,3- and 1,4-cyclohexane diisocyanate, 2,4- and 2,6-diisocyanato-1-methylcyclohexane, 1,3- and 1,4-bis(isocyanatomethyl)cyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), 4,4'-dicyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate, 1-isocyanato-1-methyl-4(3) isocyanatomethylcyclohexane, bis(isocyanatomethyl)norbornane, 1,3- and 1,4-bis(isocyanatomethyl)benzene (XDI), 1,3- and 1,4-bis(2-isocyanatopropan-2-yl)benzene (TMXDI), 2,4- and 2,6-toluene diisocyanate (TDI), 2,4'- and 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate or any desired mixture of such diisocyanates.

[0052] These diisocyanates optionally used jointly in the diisocyanate component A) during the production of the polyisocyanate mixture according to the invention, if any, are used in an amount of at most 40% by weight, preferably at most 30% by weight, particularly preferably at most 20% by weight, very particularly preferably at most 10% by weight, based on the total amount of diisocyanates used.

[0053] In another preferred embodiment, the diisocyanate component A) is based on the diisocyanate component A) and contains at least 60% by weight, preferably at least 70% by weight, particularly preferably at least 80% by weight, very particularly preferably at least 90% by weight of 1,5-pentamethylene diisocyanate and optionally at most 40% by weight, preferably at most 30% by weight, particularly preferably at most 20% by weight, very particularly preferably at most 10% by weight of other diisocyanates having aliphatic, cycloaliphatic, araliphatic and / or aromatic-bonded isocyanate groups.

[0054] Another preferred embodiment relates to a process for producing a polyisocyanate mixture, preferably a polyisocyanate mixture according to the invention, by reacting the following components

[0055] A) at least 1,5 - pentane diisocyanate and

[0056] B) at least one alcohol of general formula (II)

[0057]

[0058] wherein

[0059] R represents a straight-chain or branched, saturated or unsaturated aliphatic group and / or a saturated or unsaturated cycloaliphatic group having (6 to 22)-p carbon atoms, which may optionally be substituted in each case,

[0060] R’ and R” independently of one another represent hydrogen or an aliphatic group having 1 to 10 carbon atoms, where at least one of the groups R’ and R” represents hydrogen,

[0061] m is an integer from 1 to 10, and

[0062] p is 0 or 1.

[0063] The alcohol component B) used in the process according to the invention is at least one alcohol of general formula (II)

[0064]

[0065] wherein

[0066] R represents a straight-chain or branched, saturated or unsaturated aliphatic group and / or a saturated or unsaturated cycloaliphatic group having (6 to 22)-p, preferably having (8 to 20)-p, particularly preferably having (10 to 18)-p, very particularly preferably having (12 to 14)-p carbon atoms, which may optionally be substituted in each case,

[0067] R’ and R” independently of one another represent hydrogen or an aliphatic group having 1 to 10 carbon atoms, where at least one of the groups R’ and R” represents hydrogen, and

[0068] m is an integer from 1 to 10, preferably an integer from 1 to 7, particularly preferably an integer from 2 to 5, very particularly preferably an integer from 2 to 4, and

[0069] p is 0 or 1.

[0070] These alcohols are, for example, known alkoxylation products of fatty alcohols of general formula (III) and / or fatty acids of general formula (IV)

[0071] R 1 -OH(III),

[0072] wherein

[0073] R 1represents a straight-chain or branched, saturated or unsaturated aliphatic group and / or a saturated or unsaturated alicyclic group having 6 to 22, preferably 8 to 20, particularly preferably 10 to 18, very particularly preferably 12 to 14 carbon atoms, which may in each case be optionally substituted,

[0074] R 2 -COOH(IV)

[0075] wherein

[0076] R 2 represents a straight-chain or branched, saturated or unsaturated aliphatic group and / or a saturated or unsaturated alicyclic group 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.

[0077] For the fatty alcohols of the above general formula (III), in the general formulas (I) and (II), p is 0, and R 1 represents R, including the preferred options of R mentioned above 1 For example, suitable, preferred and particularly preferred groups R 1 and R also include groups derived from the fatty alcohols mentioned below as suitable, preferred and particularly preferred, for example.

[0078] For the fatty alcohols of the above general formula (IV), in the general formulas (I) and (II), p is 1, and R 2 represents R, including the preferred options of R mentioned above 2 For example, suitable, preferred and particularly preferred groups R 2 and R also include groups derived from the fatty acids mentioned below as suitable, preferred and particularly preferred, for example.

[0079] Fatty alcohols suitable for alkoxylation include, for example, 1-hexanol (hexanol), 1-heptanol (heptanol), 1-octanol (octanol), 1-nonanol (nonanol), 1-decanol (decanol), 1-dodecanol (lauryl alcohol), 1-tetradecanol (myristyl alcohol), 1-hexadecanol (cetyl alcohol), 1-heptadecanol (heptadecanol), 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), cis-9-hexadecen-1-ol (palmityl alcohol), cis-9-octadecen-1-ol (oleyl alcohol), trans-9-octadecen-1-ol (elaidic alcohol), cis-11-octadecen-1-ol, cis,cis-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 acid (arachidic acid), heneicosanoic acid and docosanoic acid (behenic acid), cis-9-octadecenoic acid (oleic acid) and cis-13-docosenoic acid (erucic acid).

[0080] Fatty alcohols and fatty acids made from vegetable and animal oils and fats are preferred.

[0081] Particularly preferred fatty alcohols for the production of the alcohol component B) include 1-decanol, 1-dodecanol, 1-tetradecanol and 1-octadecanol, very particularly preferred are 1-dodecanol and 1-tetradecanol. Particularly preferred fatty acids include decanoic acid, dodecanoic acid, tetradecanoic acid and hexadecanoic acid, very preferably dodecanoic acid and tetradecanoic acid. Compounds suitable for the alkoxylation of the listed fatty alcohols and / or fatty acids for the production of the alcohol component B) include any desired alkylene oxide 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, which can be used in any desired order or as a mixture for the alkoxylation reaction. Preferred alkylene oxides are those having 2 to 4 carbon atoms. Particularly preferred alkylene oxides for the production of the alcohol component B) are ethylene oxide and propylene oxide.

[0082] The number of carbon atoms of the group R' or R'' in the general formula (I) is derived from the alkylene oxides mentioned above as examples and as preferred. Thus, R' and R'' in the general formula (I) and / or formula (II) independently of one another represent hydrogen or an aliphatic group having preferably 1 to 2 carbon atoms, where at least one of the groups R' and R'' represents hydrogen.

[0083] Suitable alcohol component B) for producing the polyisocyanate mixture according to the invention particularly includes alkoxylation products of the listed fatty acids and / or fatty alcohols which statistically average 1 to 10, preferably 1 to 7, particularly preferably 2 to 5, very particularly preferably 2 to 4 alkylene oxide units. The preferred integer m according to the invention in general formula (I) and general formula (II) is derived from the values and value ranges listed above as statistical averages.

[0084] In another preferred embodiment, alcohol component B) is selected from alkoxylation products which statistically average 1 to 10, preferably 1 to 7, particularly preferably 2 to 5, very particularly preferably 2 to 4 alkylene oxide units, where the alkylene oxide units preferably comprise ethylene oxide and / or propylene oxide units or consist of ethylene oxide and / or propylene oxide units. The preferred integer m according to the invention in general formula (I) and general formula (II) is derived from the values and value ranges listed above as statistical averages.

[0085] Alcohol component B) preferably has a pH value measured in a 1% aqueous solution of the respective alcohol component B) of 4.0 to 8.0, preferably 4.5 to 7.5, particularly preferably 5.0 to 7.0, and / or a total content of alkali metal cations of at most 100 ppm, preferably 1 to 70 ppm, particularly preferably 2 to 50 ppm.

[0086] In addition to the listed alkoxylation products of fatty alcohols and / or fatty acids, component B) may optionally contain minor amounts of other alcohol compounds.

[0087] These are, for example, monohydric alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, isopentyl alcohol, hexanol, octanol and nonanol, n-decanol, n-dodecanol, n-tetradecanol, n-hexadecanol, n-octadecanol, cyclohexanol, isomethylcyclohexanol, hydroxymethylcyclohexane, 3-methyl-3-hydroxymethyloxetane, benzyl alcohol, phenol, isocresol, octylphenol, nonylphenol and naphthol, furfuryl alcohol and tetrahydrofurfuryl alcohol, unbranched aliphatic diols such as 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol and 1,8-octanediol, alicyclic diols such as 1,2- and 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 4,4'-(1-methylidene)biscyclohexanol, triols such as 1,2,3-propanetriol, 1,1,1-trimethylol ethane, 1,2,6-hexanetriol, 1,1,1-trimethylol propane and 1,3,5-tris(2-hydroxyethyl)isocyanurate, tetrafunctional alcohols such as 2,2-bis(hydroxymethyl)-1,3-propanediol or any desired mixture of these alcohols.

[0088] If any, these other alcohol compounds are used in an amount of at most 25% by weight, preferably at most 20% by weight, particularly preferably at most 15% by weight, based on the amount of the alkoxylation product based on fatty alcohols and / or fatty acids, in the process according to the invention.

[0089] For carrying out the process according to the invention, a diisocyanate component A) containing at least 1,5-pentane diisocyanate is reacted with at least one alcohol component B), preferably at a temperature of from 40 °C to 200 °C, particularly preferably from 60 °C to 180 °C, and / or while maintaining an equivalent ratio of isocyanate groups to isocyanate-reactive groups of preferably from 4:1 to 50:1, particularly preferably from 5:1 to 30:1, very particularly preferably from 10:1 to 25:1, to provide a urethane group-containing polyisocyanate.

[0090] The process according to the invention can be carried out as a thermally induced urethanation without catalysis. However, it is preferred to use a suitable catalyst to accelerate the urethanation reaction. These are the conventionally known urethanation catalysts, such as 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-3769318 (column 6, lines 5 to 49), or strong acids such as those described in, for example, EP-A-0000194 (page 13, line 27 to page 14, lines 1 to 18).

[0091] Suitable urethanation catalysts include in particular zinc compounds, such as zinc(II) stearate, zinc(II) octoate, zinc(II) 2-ethylhexanoate, zinc(II) naphthenate or zinc(II) acetylacetonate, tin compounds such as tin(II) octoate, tin(II) 2-ethylhexanoate, tin(II) laurate, dibutyltin oxide, dibutyltin dichloride, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dimaleate or dioctyltin diacetate, zirconium compounds such as zirconium(IV) 2-ethylhexanoate, zirconium(IV) neodecanoate, zirconium(IV) naphthenate or zirconium(IV) acetylacetonate, tris(ethylacetoacetato)aluminium, iron(III) chloride, potassium octoate, manganese, cobalt or nickel compounds, and strong acids such as trifluoroacetic acid, sulfuric acid, hydrogen chloride, hydrogen bromide, phosphoric acid or perchloric acid, or any desired mixture of these catalysts.

[0092] Suitable (although less preferred) catalysts for the process according to the invention are also compounds which, in addition to the urethanation reaction, catalyse the trimerization of isocyanate groups to form isocyanurate structures. Such catalysts are described, for example, in EP-A-0649866, page 4, line 7 to page 5, line 15.

[0093] Preferred catalysts for the process according to the invention are zinc and / or zirconium compounds of the above type. Very particularly preferably, at least zinc(II) octoate, zinc(II) 2-ethylhexanoate and / or zinc(II) stearate, zirconium(IV) octoate, zirconium(IV) 2-ethylhexanoate and / or zirconium(IV) neodecanoate are used.

[0094] If present, these catalysts are preferably used in an amount of 0.001% to 5% by weight, particularly preferably 0.005% to 1% by weight, based on the weight of the co-reactants A) and B), in the process according to the invention and can be added before the start of the reaction or at various times during the reaction.

[0095] Preferably, the process according to the invention does not use lead octoate as a catalyst, and accordingly, a polyisocyanate mixture according to the invention that preferably contains no catalytic amount, particularly preferably no detectable amount, of lead octoate is preferred.

[0096] The process according to the invention is preferably carried out without solvents. However, suitable solvents that are inert towards the reactive groups of the starting components can optionally be used in combination. Suitable solvents are, for example, conventional coating solvents known per se, such as ethyl acetate, butyl acetate, ethylene glycol monomethyl or monoethyl ether acetate, 1-methoxy-2-propyl acetate, 3-methoxy-n-butyl acetate, acetone, 2-butanone, 4-methyl-2-pentanone, cyclohexanone, toluene, xylene, chlorobenzene, petroleum solvents (Testbenzin), relatively highly substituted aromatic hydrocarbons, such as can be obtained, for example, under the name of (ExxonMobil Chemical Central Europe, DE) and (Shell Deutschland Oil GmbH, Hamburg, DE), and solvents such as 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 desired mixture of these solvents.

[0097] In a possible embodiment, in the process according to the invention, the starting component A) containing at least PDI is initially charged at a temperature between 20 °C and 100 °C, optionally under an inert gas, such as nitrogen, and optionally in the presence of a suitable solvent of the listed type. Subsequently, the alcohol component B) is added in the amounts mentioned above, and the reaction temperature for urethanization is optionally adjusted to a temperature of 30 °C to 120 °C, preferably 50 °C to 100 °C, by suitable measures (heating or cooling). After the urethanization reaction, i.e., when the NCO content theoretically corresponding to the complete conversion of isocyanate groups and hydroxyl groups is reached, the allophanation can be started, for example, by heating the reaction mixture to a temperature of 140 °C to 200 °C without adding a catalyst. However, it is preferred to use a suitable catalyst of the above-mentioned type to accelerate the allophanation reaction, and a temperature of 60 °C to 140 °C, preferably 80 °C to 120 °C, is usually sufficient depending on the type and amount of the catalyst used.

[0098] In another possible embodiment of the process according to the invention, the catalyst optionally used in common has been incorporated into the starting component A) containing at least PDI and / or the alcohol component B) before the actual reaction starts. In this case, the urethane groups formed as intermediates undergo a spontaneous further reaction to provide the desired allophanate structure. In this type of one-step reaction mode, optionally under an inert gas, such as nitrogen, and optionally in the presence of a suitable solvent of the listed type, the starting component A) optionally containing the catalyst is initially charged at a temperature optimal for allophanation, usually 60 °C to 140 °C, preferably 80 °C to 120 °C, and reacted with the alcohol component B) optionally containing the catalyst.

[0099] However, it is also possible to add the catalyst to the reaction mixture at any desired time during the urethanization reaction. In this embodiment of the process according to the invention, a temperature of 30 °C to 120 °C, preferably 50 °C to 100 °C, is usually established for the pure urethanization reaction carried out before the addition of the catalyst. After adding the suitable catalyst, the allophanation reaction is finally carried out at a temperature usually of 60 °C to 140 °C, preferably 80 °C to 120 °C.

[0100] In the process according to the invention, the progress of the reaction can be monitored, for example, by titrimetric determination of the NCO content in accordance with DIN EN ISO 11909:2007-05. When the target NCO content is reached, preferably when the degree of urethane formation in the reaction mixture (i.e., the percentage of the urethane groups formed between the hydroxyl groups of component B, which can be calculated from the NCO content) that have been converted into urethane groups is at least 80%, particularly preferably at least 90%, and very particularly preferably when the NCO content corresponding to complete urethane formation is reached or fallen below, the reaction is terminated. In the case of a pure thermal reaction mode, this can be achieved, for example, by cooling the reaction mixture to room temperature. However, in the case of preferably jointly using urethane formation catalysts of the type listed, the reaction is generally terminated by adding a suitable catalyst poison, such as an acid, like phosphoric acid, or an acyl chloride, like benzoyl chloride or isophthaloyl chloride.

[0101] The reaction mixture is preferably subsequently freed of volatile components (excess monomeric diisocyanate, optionally jointly used solvents, and optionally active catalysts in the case of not using a catalyst poison) by thin-film distillation under high vacuum, for example, at a pressure below 1.0 mbar, preferably below 0.5 mbar, more preferably below 0.2 mbar, under as mild conditions as possible, for example, at a temperature of 100 to 200 °C, preferably 120 to 180 °C.

[0102] The resulting distillate, which contains not only unconverted monomeric starting diisocyanate and optionally jointly used solvents but also optionally active catalysts (in the case of not using a catalyst poison), can be readily used for re-urethane formation in the process according to the invention.

[0103] In another embodiment of the process according to the invention, the listed volatile components are separated from the oligomeric product by extraction with a suitable solvent that is inert to isocyanate groups, such as an aliphatic or cycloaliphatic hydrocarbon, like pentane, hexane, heptane, cyclopentane, or cyclohexane.

[0104] Regardless of the type of post-treatment, the product obtained by the process according to the invention is a clear, almost colorless polyisocyanate mixture, which in each case has a color value of less than 100 APHA, preferably less than 80 APHA, particularly preferably less than 60 APHA, and / or an NCO content of 6.0% to 18.0% by weight, preferably 8.0% to 16.0% by weight, particularly preferably 10.0% to 15.0% by weight, and / or a residual monomer content determined by gas chromatography in accordance with DIN EN ISO 10283:2007-11 using an internal standard of less than 0.14% by weight, preferably less than 0.12% by weight, particularly preferably less than 0.10% by weight, based on the solvent-free solid resin.

[0105] Measured at a shear rate of DIN EN ISO 3219:1994-10 at 23 °C for 250 s, the viscosity of the polyisocyanate mixture according to the invention is preferably less than 500 mPas, particularly preferably less than 400 mPas, and very particularly preferably less than 300 mPas. -1 The polyisocyanate mixture according to the invention is completely crystal-stable and remains completely clear and free of turbidity even after storage at 5 °C for 4 weeks.

[0106] In another preferred embodiment, the polyisocyanate mixture according to the invention has a residual carbamate content of less than 20 mol%, preferably less than 15 mol%, particularly preferably less than 10 mol%, which is calculated by integration of the proton-decoupled

[0107] C-NMR spectrum and is based on the sum of all urethane, carbamate, isocyanurate and / or uretidione structures present in the polyisocyanate mixture according to the invention. 13 In this context, the "polyisocyanate mixture" according to the invention refers to a mixture of oligomers obtained by statistical distribution, and thus the polyisocyanate mixture according to the invention can also be referred to as the polyisocyanate according to the invention. Accordingly, in another embodiment, the invention relates to a polyisocyanate of the general formula (I)

[0108] wherein

[0109]

[0110] R represents a straight-chain or branched, saturated or unsaturated aliphatic group and / or a saturated or unsaturated cycloaliphatic group having (6 to 22)-p carbon atoms, which may optionally be substituted,

[0111] R' and R" independently of one another represent hydrogen or an aliphatic group having 1 to 10 carbon atoms, where at least one of the groups R' and R" represents hydrogen,

[0112] n is an integer from 1 to 12,

[0113] m is an integer from 1 to 10, and

[0114] p is 0 or 1.

[0115] In another embodiment, the invention relates to a process for producing a polyisocyanate, preferably a polyisocyanate according to the invention, by reacting the following components

[0116] A) a diisocyanate component containing at least 1,5-pentane diisocyanate with

[0117] B) at least one alcohol of the general formula (II)

[0118] ​

[0119]

[0120] wherein

[0121] R represents a straight-chain or branched, saturated or unsaturated aliphatic group and / or a saturated or unsaturated cycloaliphatic group having (6 to 22)-p carbon atoms, which may in each case be optionally substituted,

[0122] R' and R" independently of one another represent hydrogen or an aliphatic group having 1 to 10 carbon atoms, where at least one of the groups R' and R" represents hydrogen,

[0123] m is an integer from 1 to 10, and

[0124] p is 0 or 1.

[0125] The same preferred embodiments as in the other subjects of the present invention apply in the above two embodiments.

[0126] Since the polyisocyanate mixtures according to the invention mainly contain urethane structures as structural units, they can also be described synonymously as urethane polyisocyanates according to the invention or PDI-based urethane polyisocyanates according to the invention. The polyisocyanate mixtures according to the invention represent valuable starting materials for the production of polyurethane plastics by isocyanate polyaddition. Another subject of the present invention is therefore the use of the polyisocyanate mixtures according to the invention as starting components in the production of polyurethane plastics.

[0127] The polyisocyanate mixtures according to the invention are particularly suitable as curing agents for two-component polyurethane coatings, where conventional polyether polyols, polyester polyols, polycarbonate polyols and / or polyacrylate polyols are present as co-reactants of the polyisocyanate as the hydroxy-functional component. The preferred hydroxy-functional component is polyacrylate polyol, i.e. a polymer or copolymer of an alkyl (meth)acrylate optionally with styrene or other copolymerizable ethylenically unsaturated monomers.

[0128] They can be used as the sole crosslinking agent component, or, due to their low viscosity, can also be used particularly advantageously as reactive diluents for higher-viscosity polyisocyanates, especially those having a uretdione, isocyanurate, iminooxadiazinedione, carbamate, urethane, biuret and / or oxadiazinetrione structure with aliphatic, cycloaliphatic, araliphatic and / or aromatic-bonded isocyanate groups, preferably those based on PDI. Another subject of the present invention is the use of the polyisocyanate mixtures according to the invention for diluting higher-viscosity polyisocyanates, preferably higher-viscosity polyisocyanates based on 1,5-pentane diisocyanate, while maintaining reactivity.

[0129] Another subject of the invention is also the use of a polyisocyanate mixture according to the invention in admixture with polyisocyanates having a uretdione, isocyanurate, iminooxadiazinedione, carbamate, urethane, biuret and / or oxadiazinetrione structure with aliphatic, cycloaliphatic, araliphatic and / or aromatic-bonded isocyanate groups, preferably those based on 1,5-pentane diisocyanate. This has the advantage of further improving processability and at the same time being able to replace fossil raw materials. The subject of the invention is thus also the above-mentioned admixture of a polyisocyanate mixture according to the invention and polyisocyanates having a uretdione, isocyanurate, iminooxadiazinedione, carbamate, urethane, biuret and / or oxadiazinetrione structure with aliphatic, cycloaliphatic, araliphatic and / or aromatic-bonded isocyanate groups, preferably those based on 1,5-pentane diisocyanate.

[0130] Although the urethane polyisocyanates according to the invention or the polyisocyanate mixtures according to the invention can be used solvent-free due to their low viscosity, they can also be diluted with conventional solvents, if desired, such as the above-mentioned solvents which are inert to isocyanates and which are optionally used together in the process according to the invention, without turbidity. Usually, coating compositions formulated with the polyisocyanates according to the invention have good coating-technical properties even when dried at room temperature, and in said coating compositions, auxiliaries and additives conventional in the coating industry, such as flow control auxiliaries, color pigments, fillers or matting agents, can optionally be incorporated. However, they can of course also be dried under forced conditions at elevated temperatures or by baking at temperatures of up to 260 °C.

[0131] To control the curing rate, suitable catalysts can be used together during the formulation of the coating composition, such as catalysts conventional in isocyanate chemistry, such as tertiary amines, such as triethylamine, pyridine, methylpyridine, benzyldimethylamine, N,N'-diethylethylenediamine, N-methylpiperidine, pentamethyldiethylenetriamine, N,N-dimethylaminocyclohexane, N,N'-dimethylpiperazine or metal salts, such as iron(III) chloride, zinc chloride, zinc 2-ethylhexanoate, tin(II) octoate, tin(II) ethylhexanoate, dibutyltin(IV) dilaurate, bismuth(III) 2-ethylhexanoate, bismuth(III) octoate or molybdenum glycolate.

[0132] The urethane polyisocyanates according to the invention are also suitable as crosslinking agent components for binders or binder components which are present in dissolved or dispersed form in water and have groups reactive toward isocyanate groups, in particular alcoholic hydroxyl groups, in the production of aqueous two-component polyurethane systems. Due to their low viscosity, they can be used as such, i.e. in hydrophobic form, or in hydrophilically modified form by known methods, for example according to EP-B 0540985, EP-B 0959087 or EP-B1287052.

[0133] The urethane polyisocyanates according to the invention can also be combined with polyamines, such as the polyaspartic acid derivatives obtainable by reaction of diamines with fumaric acid esters or maleic acid esters, known from EP-B0403921, or polyamines in which the amino groups are in blocked form, such as polyketimines, polyaldimines or oxazolanes. Under the influence of moisture, free amino groups are generated from these blocked amino groups and, in the case of oxazolanes, also free hydroxyl groups, which react with the isocyanate groups of the polyisocyanates according to the invention during the crosslinking process.

[0134] The urethane polyisocyanates according to the invention can also be combined with compounds containing at least one thiol group.

[0135] These include, for example, the polythiols known from EP-A 3872108, such as simple alkylthiols, polythiols containing thioether groups, polyether thiols, polyester thiols, aromatic thio compounds and / or mercapto alcohols.

[0136] In a preferred embodiment, the isocyanate groups of the urethane polyisocyanates according to the invention can react partially or completely with at least one blocking agent.

[0137] These blocking agents are in particular the blocking agents known per se in polyurethane chemistry, such as diethyl malonate, acetoacetates, activated cyclic ketones such as cyclopentanone-2-carboxymethyl ester and carboxyethyl ester, acetone oxime, butanone oxime, ε-caprolactam, 3,5-dimethylpyrazole, 1,2,4-triazole, dimethyl-1,2,4-triazole, imidazole, diisopropylamine, benzyl tert-butylamine or any desired mixture of these blocking agents.

[0138] In blocked form, the polyisocyanates according to the invention can also be combined with the abovementioned coating binders or coating binder components for one-component PUR baking paint systems.

[0139] In all coating combinations, the amounts of the polyisocyanates and co-reactants according to the invention are such that for each optionally blocked isocyanate group, there are 0.5 to 3, preferably 0.6 to 2.0, particularly preferably 0.8 to 1.6 optionally blocked isocyanate-reactive groups. However, the urethane polyisocyanates according to the invention can optionally be admixed in minor amounts with non-functional coating binders to achieve very specific properties, for example as an additive for improving adhesion.

[0140] Substrates for coatings formulated with the polyisocyanates according to the invention that can be considered include any desired substrate, such as metals, woods, glasses, stones, ceramic materials, concretes, rigid and soft plastics, textiles, leathers, and papers, which can also optionally be provided with conventional primers before coating.

[0141] Another subject of the invention is thus a coating composition containing a urethane polyisocyanate according to the invention and a substrate at least partially coated with a polyurethane, polyurea, and / or polythiourethane according to the invention and / or at least one polyisocyanate mixture according to the invention and / or at least one coating composition according to the invention.

[0142] The coating composition according to the invention can be, for example, in the form of 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 coating binder or coating binder component having groups reactive towards isocyanate groups, or in the form of a one-component system containing at least one polyisocyanate mixture according to the invention in blocked form. These systems are also the subject of the invention.

[0143] In addition to its preferred use as a crosslinker component for solvent-free, solvent-containing, or aqueous 2K PUR coatings, the polyisocyanates according to the invention are also very suitable as crosslinkers for solvent-free or solvent-containing adhesive binders or aqueous dispersion adhesives, or as a constituent component for producing lightfast dense or foamed polyurethane moldings.

[0144] Another subject of the invention is thus polyurethanes, polyureas, and / or polythiourethanes obtainable or producible by the reaction of at least one polyisocyanate mixture according to the invention with at least one hydroxy-functional, amino-functional, and / or thio-functional component.

[0145] Features designated as preferred for the method according to the invention or the polyisocyanate mixture according to the invention are also preferred for the other subjects of the invention.

[0146] The following examples are used to illustrate the invention but should in no way be construed as imposing any limitation on the scope of protection. Examples

[0147] Unless otherwise specified, all percentage data are based on weight.

[0148] The NCO content is determined by titration according to DIN EN ISO 11909:2007-05.

[0149] All viscosity measurements are 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 -1.

[0150] The residual monomer content is measured by gas chromatography using an internal standard according to DIN EN ISO 10283:2007-11.

[0151] The contents of sodium and potassium cations are determined by inductively coupled plasma atomic emission spectrometry (ICP-OES) according to DIN EN ISO 11885:2009-09 after microwave digestion. The detection limit of this method is <1 ppm.

[0152] The platinum-cobalt color value is measured by spectrophotometry using a Lico 400 spectrophotometer from Lange, DE according to DIN EN ISO 6271-2:2005-03.

[0153] The content (mol%) of allophanate, carbamate and optionally isocyanurate and / or uretdione structures present in the polyisocyanate according to the invention is calculated by integration of the proton-decoupled 13 C-NMR spectrum (recorded on a Bruker DPX-400 instrument) and is based on the sum of the allophanate, carbamate, isocyanurate structures and / or uretdione structures present. In the case of PDI and HDI polyisocyanates dissolved in CDCl3, the individual structural units have the following chemical shifts (in ppm): allophanate: 155.7 and 153.8; carbamate 156.3; isocyanurate: 148.4; uretdione: 157.1.

[0154] Example 1 (of the present invention)

[0155] At a temperature of 80 °C under dry nitrogen, 1234 g (8.0 moles) of pentamethylene diisocyanate (PDI) and 341 g (1.0 mole) were added to a statistically average ethoxylated lauryl alcohol four times (OH value: 164.4 mg KOH / g, Na content: 34 mg / kg, K content: <1 mg / kg) and stirred for 3 hours until an NCO content of 40.0% was reached, which corresponds to complete carbamation. Then the reaction mixture was heated to 95 °C and 0.16 g of zinc(II) 2-ethylhexanoate was added as a urethane-forming catalyst. Due to the onset of the exothermic reaction, the temperature of the mixture rose to 106 °C. After a reaction time of about 30 minutes, the exotherm subsided again. The NCO content of the reaction mixture was 37.1%. The catalyst was deactivated by adding 0.16 g of orthophosphoric acid, and the unreacted monomer PDI was separated in a thin-film evaporator at a temperature of 130 °C and a pressure of 0.1 mbar. This gave 679 g of an almost colorless, clear urethane polyisocyanate with the following characteristics:

[0156] NCO content: 12.6%

[0157] Monomer PDI: 0.04%

[0158] Viscosity (23 °C): 175 mPas

[0159] Color value (APHA): 15 Hazen

[0160] Composition: Urethane: 82.6 mol%

[0161] Carbamate: 9.4 mol%

[0162] Isocyanurate: 7.6 mol%

[0163] Uretdione: 0.4 mol%

[0164] Example 2 (The present invention)

[0165] 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-ethylhexanoate as catalyst was added. 341 g (1.0 mol) of the statistically average lauryl alcohol ethoxylated four times used in Example 1 were added dropwise over a period of about 45 minutes, during which the temperature of the mixture rose to 100 °C due to the onset of the exothermic reaction. Subsequently, the reaction mixture was stirred at 100 °C until the NCO content dropped to 37.2% after about 1 hour. The catalyst was deactivated by adding 0.16 g of orthophosphoric acid, and the unreacted monomer PDI was separated off in a thin-film evaporator at a temperature of 130 °C and a pressure of 0.1 mbar. This gave 666 g of an almost colorless, clear polyisocyanate mixture having the following characteristic data and composition:

[0166] NCO content: 12.4%

[0167] Monomer PDI: 0.03%

[0168] Viscosity (23 °C): 164 mPas

[0169] Color value (APHA): 21 Hazen

[0170] Composition: Urethane: 83.0 mol%

[0171] Carbamate: 9.1 mol%

[0172] Isocyanurate: 7.5 mol%

[0173] Uretdione: 0.4 mol%

[0174] Example 3 (Comparative)

[0175] 341 g (1.0 mol) of the statistically average lauryl alcohol ethoxylated four times used in Example 1 were added to 1344 g (8.0 mol) of hexamethylene diisocyanate (HDI) at 80 °C under dry nitrogen, and the mixture was stirred for 3 hours until an NCO content of 37.4% was reached, which corresponds to complete carbamoylation. The reaction mixture was then heated to 95 °C and 0.17 g of zinc(II) 2-ethylhexanoate was added as urethane-forming catalyst. Due to the onset of the exothermic reaction, the temperature of the mixture rose to 104 °C. After a reaction time of about 30 minutes, the exotherm subsided again. The NCO content of the reaction mixture was 34.7%. The catalyst was deactivated by adding 0.17 g of orthophosphoric acid, and the unreacted monomer PDI was separated off in a thin-film evaporator at a temperature of 130 °C and a pressure of 0.1 mbar. This gave 715 g of an almost colorless urethane polyisocyanate having the following characteristic data:

[0176] NCO content: 12.3%

[0177] Monomeric HDI: 0.01%

[0178] Viscosity (23 °C): 148 mPas

[0179] Color value (APHA): 25 Hazen

[0180] Composition: Urethane: 83.3 mol%

[0181] Carbamate: 9.5 mol%

[0182] Isocyanurate: 6.6 mol%

[0183] Uretdione: 0.6 mol%

[0184] The PDI urethane polyisocyanate of the present invention from Examples 1 and 2 and a comparative HDI-based polyisocyanate were stored at room temperature for 4 weeks. The PDI polyisocyanate remained completely clear, while the HDI polyisocyanate showed visible turbidity after only one day. A distinct sediment formed after 4 weeks. This comparison shows a significantly improved crystallization stability of the PDI product compared to a comparably formed HDI derivative.

[0185] Example 4 (The present invention)

[0186] 987 g (6.4 mol) of PDI and 267 g (1.6 mol) of HDI were initially charged under dry nitrogen and stirring at a temperature of 80 °C, and 0.16 g of zinc(II) 2-ethylhexanoate as a catalyst was added. 341 g (1.0 mol) of the statistically average ethoxylated lauryl alcohol used in Example 1 was added dropwise over a period of about 30 minutes, whereupon the temperature of the mixture rose to 102 °C due to the onset of the exothermic reaction. Subsequently, the reaction mixture was further stirred at 100 °C until the NCO content dropped to 36.1% after about 1.5 hours. The catalyst was deactivated by adding 0.16 g of orthophosphoric acid, and the unreacted monomeric diisocyanates were separated off in a thin-film evaporator at a temperature of 130 °C and a pressure of 0.1 mbar. This gave 677 g of an almost colorless, clear polyisocyanate mixture having the following characteristic data and composition:

[0187] NCO content: 13.5%

[0188] Monomeric PDI: 0.01%

[0189] Monomeric HDI: 0.01%

[0190] Viscosity (23 °C): 245 mPas

[0191] Color value (APHA): 30 Hazen

[0192] Composition: Urethane: 72.7 mol%

[0193] Carbamate: 6.1 mol%

[0194] Isocyanurate: 20.7 mol%

[0195] Uretdione: 0.5 mol%

[0196] Example 5 (The present invention)

[0197] Initially, 1234 g (8.0 mol) of PDI was charged at a temperature of 95 °C under dry nitrogen and stirring, and 0.32 g of zirconium(IV) 2-ethylhexanoate as a catalyst was added. 341 g (1.0 mol) of the statistically average ethoxylated lauryl alcohol used in Example 1 was added dropwise over a period of about 45 minutes, during which the temperature of the mixture rose to 107 °C due to the start of the exothermic reaction. Subsequently, the reaction mixture was further stirred at 100 °C until the NCO content dropped to 37.1% after about 1.5 hours. The catalyst was deactivated by adding 0.32 g of orthophosphoric acid, and the unreacted monomer PDI was separated in a thin-film evaporator at a temperature of 130 °C and a pressure of 0.1 mbar. This gave 658 g of an almost colorless, clear polyisocyanate mixture having the following characteristic data and composition:

[0198] NCO content: 12.2%

[0199] Monomer PDI: 0.03%

[0200] Viscosity (23 °C): 150 mPas

[0201] Color value (APHA): 15 Hazen

[0202] Composition: Urethane: 88.1 mol%

[0203] Carbamate: 6.6 mol%

[0204] Isocyanurate: 4.8 mol%

[0205] Uretdione: 0.5 mol%

[0206] Examples 6 to 13 (The present invention)

[0207] By the method described in Example 2, PDI was reacted with lauryl alcohol ethoxylates having different degrees of ethoxylation at different NCO:OH equivalent ratios under the catalysis of zinc octoate, and post-treatment was carried out by thin-film distillation. The following table shows the reaction batches and the composition and characteristic data of the urethane group-containing polyisocyanates obtained after thin-film distillation.

[0208]

[0209]

Claims

1. A polyisocyanate mixture comprising at least one polyisocyanate of the general formula (I) wherein R represents a straight-chain or branched, saturated or unsaturated aliphatic group and / or a saturated or unsaturated cycloaliphatic group having (6 to 22)-p carbon atoms, which may in each case be optionally substituted, R' and R" independently of one another represent hydrogen or an aliphatic group having 1 to 10 carbon atoms, where at least one of the groups R' and R" represents hydrogen, n is an integer from 1 to 12, m is an integer from 1 to 10, and p is 0 or 1.

2. The polyisocyanate mixture according to claim 1, having an NCO content of from 6.0% to 18.0% by weight, preferably from 8.0% to 16.0% by weight, particularly preferably from 10.0% to 15.0% by weight, based on the total weight of the polyisocyanate mixture, and / or a residual monomer content of less than 0.14% by weight, preferably less than 0.12% by weight, particularly preferably less than 0.10% by weight, based on the total weight of the polyisocyanate mixture, measured by gas chromatography using an internal standard according to DIN EN ISO 10283:2007-11.

3. The polyisocyanate mixture according to claim 1 or 2, having a viscosity measured at 23 °C at a shear rate of 250 s -1 according to DIN EN ISO 3219:1994-10 of less than 500 mPas, preferably less than 400 mPas, particularly preferably less than 300 mPas. -1 ​ 4. A process for producing a polyisocyanate mixture according to any one of claims 1 to 3, characterized in that React the following components A) a diisocyanate component containing at least 1,5-pentane diisocyanate with B) at least one alcohol of the general formula (II) wherein R represents a straight-chain or branched, saturated or unsaturated aliphatic group and / or a saturated or unsaturated cycloaliphatic group having (6 to 22)-p carbon atoms, which may in each case be optionally substituted, R' and R" independently of one another represent hydrogen or an aliphatic group having 1 to 10 carbon atoms, where at least one of the groups R' and R" represents hydrogen, n is an integer from 1 to 12, m is an integer from 1 to 10, and p represents 0 or 1.

5. The method according to claim 4, wherein 1,5-Pentamethylene diisocyanate and, based on the diisocyanate component A), up to 40% by weight of other diisocyanates optionally having aliphatic, cycloaliphatic, araliphatic and / or aromatic-bonded isocyanate groups are used as the diisocyanate component A).

6. The method according to claim 4 or 5, characterized in that As the alcohol component B), an alkoxylation product of a fatty alcohol of the general formula (III) R 1 -OH(III), wherein R 1 represents a straight-chain or branched, saturated or unsaturated aliphatic group and / or a saturated or unsaturated alicyclic group having 6 to 22, preferably 8 to 20, particularly preferably 10 to 18, very particularly preferably 12 to 14 carbon atoms, which may in each case be optionally substituted, and / or an alkoxylation product of a fatty acid of the general formula (IV) R 2 -COOH (IV), wherein R 2 represents a straight-chain or branched, saturated or unsaturated aliphatic group and / or a saturated or unsaturated alicyclic group having 5 to 21, preferably 7 to 19, particularly preferably 9 to 17, very particularly preferably 11 to 13 carbon atoms, which may optionally be substituted in each case.

7. The method according to any one of claims 4 to 6, characterized in that The alcohol component B) used includes alkoxylation products of 1-decanol, 1-dodecanol, 1-tetradecanol, 1-octadecanol, decanoic acid, dodecanoic acid, tetradecanoic acid and / or hexadecanoic acid.

8. The method according to any one of claims 4 to 7, characterized in that The alcohol component B) includes alkoxylation products having on statistical average from 1 to 10, preferably from 1 to 7, particularly preferably from 2 to 5, very particularly preferably from 2 to 4 alkylene oxide units, where the alkylene oxide units preferably comprise ethylene oxide and / or propylene oxide units or consist of ethylene oxide and / or propylene oxide units.

9. The method according to any one of claims 4 to 8, characterized in that React a diisocyanate component A) containing at least 1,5-pentane diisocyanate with at least one alcohol component B) at a temperature of from 40°C to 200°C, preferably from 60°C to 180°C, and / or while maintaining an equivalent ratio of isocyanate groups to isocyanate-reactive groups of from 4:1 to 50:1, preferably from 5:1 to 30:1, to provide a urethane polyisocyanate.

10. The method according to any one of claims 4 to 9, characterized in that React a diisocyanate component A) containing at least 1,5-pentane diisocyanate with at least one alcohol component B) in the presence of at least one urethane-formation catalyst, preferably at least zinc(II) octoate, zinc(II) 2-ethylhexanoate and / or zinc(II) stearate, zirconium(IV) octoate, zirconium(IV) 2-ethylhexanoate and / or zirconium(IV) neodecanoate.

11. Use of the polyisocyanate mixture according to any one of claims 1 to 3 as a starting component in the production of polyurethane plastics.

12. Use of the polyisocyanate mixture according to any one of claims 1 to 3 for blending with polyisocyanates having a uretdione, isocyanurate, iminooxadiazinedione, carbamate, urethane, biuret and / or oxadiazinetrione structure with aliphatic, cycloaliphatic, araliphatic and / or aromatic-bonded isocyanate groups, preferably those based on 1,5-pentane diisocyanate.

13. Use of the polyisocyanate mixture according to any one of claims 1 to 3 for diluting higher-viscosity polyisocyanates, preferably higher-viscosity polyisocyanates based on 1,5-pentane diisocyanate, while maintaining reactivity.

14. Polyurethanes, polyureas and / or polythiourethanes obtainable or producible by reacting at least one polyisocyanate mixture according to any one of claims 1 to 3 with at least one hydroxy-functional, amino-functional and / or thio-functional component.

15. A coating composition containing at least one polyisocyanate mixture according to any one of claims 1 to 3, wherein the at least one polyisocyanate mixture according to any one of claims 1 to 3 is preferably present in admixture with polyisocyanates having a uretdione, isocyanurate, iminooxadiazinedione, carbamate, urethane, biuret and / or oxadiazinetrione structure with aliphatic, cycloaliphatic, araliphatic and / or aromatic-bonded isocyanate groups, preferably those based on 1,5-pentane diisocyanate.

16. A substrate at least partially coated with at least one polyisocyanate mixture according to any one of claims 1 to 3 and / or at least one polyurethane, polyurea and / or polythiourethane according to claim 14 and / or at least one coating composition according to claim 15.

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