Preparation of blocked hardeners based on partially organic polyisocyanates and their use in 1K PUR baking enamels.

Abstract

The present invention relates to a method for producing an isocyanate-containing polymerizable composition comprising: a polymerizable composition for producing an isocyanate-containing polymerizable composition, the polymerizable composition comprising ... 1 Group (where R 1 is selected from H or OH, N being linked to other atoms of the compound via two single or double bonds, characterized in that the former is formed from at least one polyisocyanate based on 1,5-pentamethylene diisocyanate, which to a maximum of 51% by weight or more has a content of isocyanurate trimers of 60% or less by area, determined by gel permeation chromatography according to DIN 55672-1:2007-08, based on the total weight of the polyisocyanate based on 1,5-pentamethylene diisocyanate, and the remaining proportions up to 100% by weight of the total amount of polyisocyanates contained in the former comprise or consist of at least one aliphatic or cycloaliphatic polyisocyanate. The invention also relates to the use of this polyisocyanate composition for producing a one-component system, and to a one-component system containing this polyisocyanate composition and at least one polyol. Furthermore, the present invention relates to a method for producing a coating on a substrate, in which the one-component system according to the present invention is applied to the substrate and cured at a temperature in the range of 80° C. to 300° C., and to the coating thus produced. Finally, the present invention relates to a composite consisting of a coating according to the present invention and a substrate having a surface made of a metal and / or plastic material.

Description

[Technical field]

[0001] The present invention relates to a method for producing an isocyanate-containing polymerizable composition comprising: a polymerizable composition for producing an isocyanate-containing polymerizable composition, the polymerizable composition comprising ... 1 Group (where R 1 is selected from H or OH, N being linked to other atoms of the compound via two single or double bonds, characterized in that the former is formed from at least one polyisocyanate based on pentamethylene 1,5-diisocyanate, which to an extent of 51% by weight or more has a content of isocyanurate trimers of 60% by area or less, determined by gel permeation chromatography according to DIN 55672-1:2007-08, based on the total weight of polyisocyanates based on pentamethylene 1,5-diisocyanate, and the remainder up to 100% by weight of the total amount of polyisocyanates present in the former comprises or consists of at least one aliphatic or cycloaliphatic polyisocyanate. The invention further relates to the use of this polyisocyanate composition for producing a one-component system, and to a one-component system comprising this polyisocyanate composition and at least one polyol. Furthermore, the present invention relates to a method for producing a coating on a substrate, in which the one-component system according to the present invention is applied to the substrate and cured at a temperature in the range of 80° C. to 300° C., and to the coating thus produced. Finally, the present invention relates to a composite consisting of a coating according to the present invention and a substrate having a metal and / or plastic surface. [Background technology]

[0002] Coatings based on polyisocyanate compositions are known and commercially available.Typical of these are HDI (hexamethylene 1,6-diisocyanate)-based compositions (e.g., based on Desmodur® N3300, available from Covestro AG), in which isocyanate groups are blocked, for example, with N-containing azole compounds, in order to improve the storage stability and handling of coating systems.However, such products show relatively low hardness as well as low weathering stability. Summary of the Invention

[0003] It was therefore an object of the present invention to provide a polyisocyanate composition having partially blocked isocyanate groups which overcomes the above mentioned drawbacks.

[0004] The inventors of the present invention have surprisingly found that this is at least one isocyanate group-reactive compound, which comprises at least one NR 1 Group (where R 1 It has been found that this can be achieved using the specific polyisocyanate compositions of the present invention based on PDI (pentamethylene 1,5-diisocyanate) blocked with at least one isocyanate group-reactive compound containing (N is selected from H or OH, N is attached to other atoms of the compound via two single or double bonds). Thus, more sustainable compositions are also provided.

[0005] This is particularly surprising, since, for PDI-based compositions blocked with CH-acidic reagents, the introduction of WO 2017 / 021150 states that it is assumed that disadvantages are to be expected in the case of the additional use of oximes or 3,5-dimethylpyrazoles in PDI-based polyisocyanates.Furthermore, the present compositions are advantageous in that, in contrast to the compositions described in the aforementioned documents, no crystallization inhibitors are required.

[0006] Thus, in a first aspect, the present invention provides a composition comprising an isocyanate group-containing forming component, the isocyanate groups of which have reacted with at least one isocyanate group-reactive compound to an extent of 50% or more, preferably 60% or more, more preferably 70% or more, most preferably 80% or more, 90% or more or 95% or more, and the isocyanate group-reactive compound is at least one NR 1 Group (where R 1 is selected from H or OH, N being linked to other atoms of the compound via two single or double bonds, characterized in that the former is formed to an extent of 51% by weight or more from at least one polyisocyanate based on pentamethylene 1,5-diisocyanate, which has a content of isocyanurate trimers of 60% by area or less, determined by gel permeation chromatography in accordance with DIN 55672-1:2007-08, based on the total weight of polyisocyanates based on pentamethylene 1,5-diisocyanate, and the remainder up to 100% by weight of the total amount of polyisocyanates present in the former comprises or consists of at least one aliphatic or cycloaliphatic polyisocyanate.

[0007] In a second aspect, the present invention relates to the use of the polyisocyanate composition according to the invention for producing one-component systems, in particular one-component coating systems.

[0008] In a third aspect, the present invention relates to a one-component system comprising at least one polyisocyanate composition according to the invention, at least one polyol and optionally further additives.

[0009] In a fourth aspect, the present invention relates to a method for producing a coating on a substrate, in which the one-component system of the present invention is applied to the substrate and cured at a temperature in the range of 80°C to 300°C, preferably in the range of 90°C to 250°C.

[0010] In a fifth aspect, the present invention relates to a coating produced or producible by the method according to the invention.

[0011] Finally, the invention relates in a sixth aspect to a composite consisting of a coating according to the invention and a substrate having a metal and / or plastic surface.

[0012] According to the invention, a trimer structure is understood to mean the following isocyanurate structural units which are formed from diisocyanates and which are randomly linked to one another according to an oligomeric distribution:

[0013] [ka] The specification of the content of isocyanurate trimers as a weight percentage based on the total weight of the respective polyisocyanate refers, according to the present invention, to compounds in the polyisocyanate composition that contain exactly one isocyanurate group and three isocyanate groups. The content of isocyanurate trimers is determined as area percent (area%) by gel permeation chromatography (GPC) according to DIN 55672-1:2007-08.

[0014] In a first preferred embodiment, the forming components consist of at least one polyisocyanate based on pentamethylene 1,5-diisocyanate, which has a content of isocyanurate trimers of 60% or less by area, based on the total weight of the polyisocyanate based on pentamethylene 1,5-diisocyanate, to an extent of at least 60% by weight, preferably to an extent of at least 70% by weight, particularly preferably to an extent of at least 80% by weight, which offers the advantage, inter alia, that the storage stability can be further increased.

[0015] This further has the advantage that the proportion of bio-origin in the polyisocyanate composition according to the invention can be increased even further, so that in this case it is very particularly preferred if the forming components consist to the extent of 100% by weight of at least one polyisocyanate based on pentamethylene 1,5-diisocyanate.

[0016] In a further preferred embodiment, the content of isocyanurate trimers is ≧36% to ≦56% by area, preferably ≧38% to ≦51% by area, based on the total weight of the pentamethylene 1,5-diisocyanate-based polyisocyanate.

[0017] According to a further preferred embodiment, the remainder up to 100% by weight of the total amount present in the forming components consists of at least one aliphatic or cycloaliphatic polyisocyanate, at least 5% by weight, preferably at least 10% by weight, particularly preferably at least 15% by weight.

[0018] Polyisocyanates based on pentamethylene 1,5-diisocyanate are obtained by modification of pentamethylene 1,5-diisocyanate (PDI) and are any desired oligomeric polyisocyanates having uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structures, or any desired mixtures of such polyisocyanates. These polyisocyanates are prepared by processes known per se for isocyanate oligomerization, for example described in J.Prakt.Chem.336(1994)185-200 and EP 0798299, by reacting some of the isocyanate groups of PDI to form polyisocyanate molecules consisting of at least two diisocyanate molecules, generally followed by distillation or extraction removal of the unreacted monomeric PDI.

[0019] The PDI used to prepare the polyisocyanates based on pentamethylene 1,5-diisocyanate is obtained in various ways, for example by phosgenation in the liquid or gas phase, or by a phosgene-free route, for example by thermal urethane cleavage proceeding from 1,5-diaminopentane, preferably obtained by biotechnology, via decarboxylation of the natural amino acid lysine.

[0020] The trimerization reaction is preferably terminated after the desired isocyanurate trimer content is reached, since the content of isocyanurate trimer can be adjusted by appropriate reaction regime.This can be achieved, for example, by cooling the reaction mixture to room temperature.However, the reaction is generally terminated by adding one or more catalyst poisons known to those skilled in the art, and optionally subsequently heating the reaction mixture for a short time, for example to a temperature above 80°C.

[0021] Aliphatic or cycloaliphatic polyisocyanates different from the polyisocyanates based on pentamethylene 1,5-diisocyanate can be obtained by modification of suitable monomeric diisocyanates to any desired oligomeric polyisocyanates having uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structures, or any desired mixtures of such polyisocyanates. These polyisocyanates are prepared by reacting part of the isocyanate groups of monomeric diisocyanates to form polyisocyanate molecules consisting of at least two diisocyanate molecules, generally followed by distillation or extraction to remove the unreacted monomeric diisocyanates, by methods known per se for isocyanate oligomerization, as described, for example, in J.Prakt.Chem.336(1994)185-200.

[0022] Suitable monomeric diisocyanates are in particular those in the molecular weight range from 140 to 400, such as 1,4-diisocyanatobutane, hexamethylene 1,6-diisocyanate (HDI), 2-methyl-1,5-diisocyanatopentane, 1,5-diisocyanato-2,2-dimethylpentane, 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanatohexane, 1,10-diisocyanatodecane, 1,3- and 1,4-diisocyanatocyclohexane, 2,4- and 2,6-diisocyanato-1-methylcyclohexane, 1,3- and 1,4-diisocyanatobutane, hexamethylene 1,6-diisocyanatobutane ..., hexamethylene 1,6-diisocyanatobutane, hexamethylene 1,6-diisocyanatobutane, hexamethylene 1,6-diisocyanatobutane, hexamethylene 1,6-diisocyanatobutane, hexamethylene 1,6-diisocyanatobutane, hexamethylene 1,6-diisocyanatobutane, hexamethylene 1,6-diisocyanatobutane, hexamethylene 1,6-diisocyanato Bis(isocyanatomethyl)cyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), 4,4'-diisocyanatodicyclohexylmethane, 2,4'-diisocyanatodicyclohexylmethane, 1-isocyanato-1-methyl-4(3)-isocyanatomethylcyclohexane, bis(isocyanatomethyl)norbornane, 1,3- and 1,4-bis(isocyanatomethyl)benzene (XDI) or any desired mixture of such diisocyanates. It is generally preferred that the residual monomer content of the monomeric diisocyanates in the polyisocyanate composition according to the invention is less than 0.5% by weight, particularly preferably less than 0.3% by weight. The residual monomer content can be determined, for example, by gas chromatography according to DIN EN ISO 10283:2006-04.

[0023] It is further preferred that the remainder up to 100% by weight of the total amount of polyisocyanates present in the forming components consists of at least one aliphatic polyisocyanate.

[0024] In a preferred embodiment, the at least one isocyanate group-reactive compound is selected from N-containing azole compounds, oximes, amines or lactams or mixtures thereof; more preferably, the compound is selected from pyrazoles, ketoximes, secondary amines or lactams or mixtures thereof; particularly preferably, the compound is selected from 3,5-dimethylpyrazole, 3,5-diisopropylpyrazole, 3,5-di-tert-butylpyrazole, 3,5-diphenylpyrazole, butanone oxime, 2-pentanone oxime, cyclohexanone oxime, 4-methyl-2-pentanone oxime, diisopropylamine, N-benzyl-tert-butylamine or ε-caprolactam or mixtures thereof; most preferably, the compound is 3,5-dimethylpyrazole or butanone oxime.

[0025] Alternatively or additionally, the at least one isocyanate group-reactive compound is a piperidone compound of the general formula (1)

[0026] [ka] (In the formula, R 1 ~R 4 Each of the groups is an alkyl group having 1 to 4 carbon atoms, and R 1 ~R 4 may be identical or different, R 5 ~R 8 Each of the groups is an alkyl group having 1 to 4 carbon atoms or hydrogen, and R 5 ~R 8 may be the same or different here) It is preferable that it is not.

[0027] Alternatively or additionally, it is preferred that the at least one isocyanate group-reactive compound is not a piperidone-based compound of EP 3950759.

[0028] Subsequent deblocking of the blocking groups formed from these compounds is carried out at temperatures between 80°C and 300°C.

[0029] In addition to the isocyanate group-containing formers and the blocking compounds, the polyisocyanate compositions according to the invention may also comprise further compounds.

[0030] In general, the polyisocyanate compositions according to the invention may be present without solvent, although it is possible for one or more solvents to be present which are inert towards the reactive groups of the components used.

[0031] Suitable solvents are, for example, conventional coating solvents known per se, such as, for example, 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, volatile oils, such as, for example, solvent naphtha, relatively highly substituted aromatics such as those commercialized under the names Solvesso®, Isopar®, Nappar®, Varsol® (ExxonMobil Chemical Central Europe, Cologne, Germany) and Shellsol® (Shell Deutschland Oil GmbH, Hamburg, Germany), as well as solvents such as propylene glycol diacetate, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, diethylene glycol ethyl and butyl ether acetates, N-methylpyrrolidone and N-methylcaprolactam, or any desired mixtures of such solvents.

[0032] In a further preferred embodiment, the polyisocyanate composition according to the invention comprises at least one organic solvent, preferably solvent naphtha, for example solvent naphtha 100, methoxypropyl acetate, butyl acetate, xylene and mixtures thereof, particularly preferably solvent naphtha 100, methoxypropyl acetate and mixtures thereof.

[0033] By choosing the amount of solvent, the solids content of the polyisocyanate compositions according to the invention can be varied within wide limits in the case of the preferred combination of organic solvents, in which case it is very particularly preferred for the polyisocyanate compositions according to the invention to have a solids content of ≧10% by weight and ≦95% by weight, preferably ≧25% by weight and ≦85% by weight.

[0034] The polyisocyanate composition according to the invention is obtainable by reacting the isocyanate groups of the polyisocyanate present in the isocyanate group-containing forming component with at least one of the reactive compounds described above.

[0035] This reaction converts the isocyanate groups of the polyisocyanate into a stable adduct that produces a storage stable mixture with the polyol at room temperature. At temperatures above 80°C, the blocking agent releases isocyanate groups for crosslinking with the polyol component.

[0036] The polyisocyanate compositions according to the invention are therefore very suitable for producing one-component systems, such uses being therefore further provided by the invention, for which purpose the polyisocyanate compositions according to the invention are mixed with the further compounds described below.

[0037] The present invention further provides a one-component system comprising at least one polyisocyanate composition according to the invention, at least one polyol and, optionally, further additives. The one-component system according to the invention is advantageously distinguished by high hardness and weathering stability compared to conventional blocked one-component systems.

[0038] Suitable polyols are, for example, polyether polyols, polyester polyols, polycarbonate polyols or polyacrylate polyols.

[0039] The optional additives present may be, for example, those known to the person skilled in the art: cobinders, drying agents, fillers, cosolvents, colour or effect pigments, coating additives such as thickeners, matting agents, light stabilizers, dispersants, thickeners, defoamers and other additives such as adhesives, fungicides, bactericides, stabilizers or inhibitors, and catalysts or emulsifiers.

[0040] The invention further provides a method for producing a coating on a substrate, which comprises applying a one-component system according to the invention to the substrate and curing at a temperature between 80°C and 300°C.

[0041] The one-component system according to the present invention can be applied on any desired substrate by known methods, such as spraying, painting, flow coating, or with the aid of roller or doctor blade.Examples of suitable substrates include metal, glass, stone, ceramic material, concrete, plastic, composite material, textile, leather or paper, and may be provided with a conventional primer before coating.Particularly preferred substrates are those with metal and / or plastic surface.

[0042] Therefore, the present invention further provides a coating produced or producible by the method according to the present invention.

[0043] As well as the coating itself, the present invention further provides a composite comprising a coating according to the invention and a substrate having a metal and / or plastic surface.

[0044] The present invention relates in particular to the following embodiments: 1. According to a first embodiment, the present invention provides a composition comprising an isocyanate group-containing forming component, the isocyanate groups of which have reacted to an extent of 50% or more with at least one isocyanate group-reactive compound, the isocyanate group-reactive compound being at least one NR 1 Group (where R 1 is selected from H or OH, N being linked to other atoms of the compound via two single or double bonds, characterized in that the former is formed to an extent of 51% by weight or more from at least one polyisocyanate based on pentamethylene 1,5-diisocyanate, which has a content of isocyanurate trimers of 60% by area or less, determined by gel permeation chromatography in accordance with DIN 55672-1:2007-08, based on the total weight of polyisocyanates based on pentamethylene 1,5-diisocyanate, and the remainder up to 100% by weight of the total amount of polyisocyanates present in the former comprises or consists of at least one aliphatic or cycloaliphatic polyisocyanate.

[0045] 2. The polyisocyanate composition according to embodiment 1, characterized in that the forming component is formed to an extent of at least 60% by weight from at least one polyisocyanate based on pentamethylene 1,5-diisocyanate, which has a content of isocyanurate trimers of 60% or less by area, based on the total weight of the polyisocyanate based on pentamethylene 1,5-diisocyanate.

[0046] 3. The polyisocyanate composition according to embodiment 1 or 2, characterized in that the content of isocyanurate trimers is 36% by area or more and 56% by area or less, based on the total weight of the polyisocyanate based on pentamethylene 1,5-diisocyanate.

[0047] 4. The polyisocyanate composition according to any one of the preceding claims, characterized in that the remainder to 100% by weight of the total amount of polyisocyanates present in the forming components consists of aliphatic or cycloaliphatic polyisocyanates to the extent of at least 5% by weight.

[0048] 5. At least one isocyanate group-reactive compound is a piperidone compound represented by the general formula (1)

[0049] [ka] (In the formula, R 1 ~R 4 Each of the groups is an alkyl group having 1 to 4 carbon atoms, and R 1 ~R 4 may be identical or different, R 5 ~R 8 Each of the groups is an alkyl group having 1 to 4 carbon atoms or hydrogen, and R 5 ~R 8 may be the same or different here) 5. The polyisocyanate composition according to any one of the preceding claims, wherein the polyisocyanate composition is not:

[0050] 6. Polyisocyanate composition according to any of the preceding claims, characterized in that at least one isocyanate group-reactive compound is selected from N-containing azole compounds, oximes, amines or lactams or mixtures thereof.

[0051] 7. Polyisocyanate composition according to any of the preceding claims, characterized in that at least one isocyanate group-reactive compound is selected from pyrazoles, ketoximes, secondary amines or lactams or mixtures thereof.

[0052] 8. Polyisocyanate composition according to any of the preceding claims, characterized in that the at least one isocyanate group-reactive compound is selected from 3,5-dimethylpyrazole, 3,5-diisopropylpyrazole, 3,5-di-tert-butylpyrazole, 3,5-diphenylpyrazole, butanone oxime, 2-pentanone oxime, cyclohexanone oxime, 4-methyl-2-pentanone oxime, diisopropylamine, N-benzyl-tert-butylamine, ε-caprolactam or mixtures thereof.

[0053] 9. The polyisocyanate composition according to any one of the preceding embodiments, characterized in that the remainder to 100% by weight of the total amount of polyisocyanates present in the forming components consists of at least one aliphatic polyisocyanate.

[0054] 10. The polyisocyanate composition according to any one of the preceding embodiments, wherein the polyisocyanate composition comprises at least one organic solvent.

[0055] 11. Use of the polyisocyanate composition according to any of embodiments 1 to 10 for producing a one-component system.

[0056] 12. A one-component system comprising at least one polyisocyanate composition according to any of embodiments 1 to 10, at least one polyol and optionally further additives.

[0057] 13. A method for producing a coating on a substrate, comprising applying the one-component system according to embodiment 12 to the substrate and curing at a temperature ranging from 80°C to 300°C.

[0058] 14. A coating produced or producible by the method of embodiment 13.

[0059] 15. A composite comprising a coating according to embodiment 14 and a substrate having a metal and / or plastic surface.

[0060] The present invention is explained in more detail below using examples which should not be construed as limiting.

[0061] [Example] Unless otherwise stated, all percentages are by weight.

[0062] The NCO content was determined by titration in accordance with DIN EN ISO 11909:2007-05.

[0063] All viscosity measurements were carried out on an MCR302 from Anton Paar Germany GmbH (Germany) according to DIN EN ISO 3219:1994-10.

[0064] The color numbers were measured spectrophotometrically according to DIN EN 1557:1996 using a LICO 690 spectrocolorimeter from Lange, Germany.

[0065] The solvent and water resistance was determined in accordance with DIN EN ISO 4628-1:2016-07.

[0066] The non-volatile fraction (NVF) is determined in accordance with DIN EN ISO 3251:2019.

[0067] Determination of renewable fractions by isotopic analysis was performed according to ASTM-D6866-20.

[0068] List of product names and abbreviations Covestro Products Desmodur® N 3300 100% Aliphatic Polyisocyanates (HDI Isocyanurates) in the as-supplied form NCO content: 21.8% Viscosity: Approximately 3000 mPas at 23°C Desmodur® eco N 7300 100% Aliphatic Polyisocyanate (PDI Isocyanurate) in the as-supplied form NCO content: 21.75% Viscosity: Approximately 9500 mPas at 23°C Uralac® SN844 S2G3-60ND 60% saturated polyester in as-supplied form in 150ND solvent naphtha / butyl glycol (30 / 10) OHN: 30-35mg KOH / g Viscosity: 2.8-3.2 Pas at 23°C Dimethylpyrazole was obtained from Wacker Chemie AG (Germany).

[0069] Acetylacetone was obtained from Daicel Chemical Industries, Ltd. (Japan).

[0070] Hydrazine hydrate was obtained from Merck KGaA Germany.

[0071] · Solvent naphtha 100 was obtained from Brenntag GmbH.

[0072] Methoxypropyl acetate was obtained from OQema GmbH.

[0073] Solvent naphtha 150 ND was obtained from DHC.

[0074] Butyl glycol was obtained from Brenntag GmbH.

[0075] · Kronos 2360 (titanium dioxide) was obtained from Kronos.

[0076] Dibutyltin dilaurate was obtained from DB Becker Co Inc.

[0077] ·Urad dd27 ND (acrylate polymer as surface additive) was obtained from Synres BV.

[0078] [Comparative Example 1] (Comparative Example) To 260 g of acetylacetone, first add the appropriate amount of solvent. Nitrogen is introduced and the mixture is heated to 70° C. 130 g of hydrazine hydrate are added dropwise over 30 minutes. During the exothermic reaction, the reaction temperature rises to 95-98° C. The reaction temperature is increased to 150° C. during the separation of water until the separation is complete. The reaction is cooled to 73° C. and 501 g of Desmodur N® 3300 are metered in portions. The reaction temperature is increased to 90° C. The mixture is stirred until a theoretical NCO content of 0.0% by weight is reached.

[0079] After cooling to room temperature, the characteristic data viscosity, color number and non-volatile fraction are determined: Viscosity: 4300mPas at 23℃ Number of colors: 100Hz or less Non-volatile fraction: 75±2% Blocked NCO content: 10.5% Renewable fraction: 0% [Example 1] (Example according to the present invention) 501 g of Desmodur® eco N 7300 are first added under nitrogen with the appropriate amount of solvent and heated to 50° C. Then 249 g of dimethylpyrazole are metered in portionwise over 2 hours and the mixture is stirred at 70° C. until the solids are dissolved and a theoretical NCO content of 0.0% by weight is reached.

[0080] After cooling to room temperature, the characteristic data viscosity, color number and non-volatile fraction are determined: Viscosity: 8500mPas at 23℃ Number of colors: 100Hz or less Non-volatile fraction: 75±2% Blocked NCO content: 10.9% Renewable fraction: 32% Coating Testing: Unless otherwise stated, all percentages are by weight.

[0081] The König pendulum damping was determined in accordance with DIN 53157, ISO 1522.

[0082] Gloss measurements are performed in accordance with NEN-EN 13523-2:2014, ISO 2813.

[0083] The T-bend test was performed according to NEN-EN 13523-7:2014.

[0084] Pencil hardness was measured according to NEN-EN 13523-4:2014.

[0085] The colour of the weathered coatings was determined according to DIN EN ISO 11664 (part 4).

[0086] Accelerated weathering is carried out in accordance with DIN EN ISO 16474-2, method A, cycle number 1 (xenon).

[0087] [Example of use] (according to the present invention) To investigate the coating properties, formulations were prepared based on the heat-activatable curing agents from Comparative Example 1 and Example 1 and in each case Uralac® SN844 S2G3 60 ND with an NCO:OH ratio of 1:1. The solvent used was a mixture of Solvent Naphtha 150 ND and Butyl Glycol in a ratio of 3:1. The details of the coating formulations are listed in Table 1.

[0088] These coating formulations were applied to aluminum substrates using a doctor blade and baked at a peak metal temperature of 241° C. Layer thicknesses were 20-22 μm in all cases.

[0089] [Table 1]

[0090] [Table 2]

[0091] Both materials show comparable properties in terms of flexibility. In terms of hardness and weathering stability, the formulation based on Example 1 according to the invention shows better properties.

Claims

1. The composition comprises an isocyanate group-containing forming component, wherein the isocyanate groups have reacted to a degree of 50% or more with at least one isocyanate group-reactive compound, and the isocyanate group-reactive compound is at least one N—R １ group (where R １ is selected from H or OH, and N is linked to other atoms of the compound via two single or double bonds, characterized in that the former is formed to an extent of 51% by weight or more from at least one polyisocyanate based on pentamethylene 1,5-diisocyanate, which has a content of isocyanurate trimers of 60% by area or less, determined by gel permeation chromatography in accordance with DIN 55672-1:2007-08, based on the total weight of polyisocyanates based on pentamethylene 1,5-diisocyanate, and the remainder up to 100% by weight of the total amount of polyisocyanates present in the former comprises or consists of at least one aliphatic or cycloaliphatic polyisocyanate.

2. 2. The polyisocyanate composition according to claim 1, characterized in that the forming component is formed from at least one polyisocyanate based on pentamethylene 1,5-diisocyanate, which to an extent of at least 60% by weight has a content of isocyanurate trimers of not more than 60% by area, based on the total weight of the polyisocyanate based on pentamethylene 1,5-diisocyanate.

3. 2. The polyisocyanate composition according to claim 1, wherein the content of the isocyanurate trimer is 36% by area or more and 56% by area or less based on the total weight of the pentamethylene 1,5-diisocyanate-based polyisocyanate.

4. 2. The polyisocyanate composition according to claim 1, characterized in that the remainder to 100% by weight of the total amount of polyisocyanates present in the forming components consists of aliphatic or cycloaliphatic polyisocyanates to an extent of at least 5% by weight.

5. 2. The polyisocyanate composition according to claim 1, characterized in that the at least one isocyanate group-reactive compound is selected from N-containing azole compounds, oximes, amines or lactams or mixtures thereof.

6. 2. The polyisocyanate composition of claim 1, wherein the at least one isocyanate group-reactive compound is selected from pyrazoles, ketoximes, secondary amines or lactams or mixtures thereof.

7. 2. The polyisocyanate composition according to claim 1, characterized in that the at least one isocyanate group-reactive compound is selected from 3,5-dimethylpyrazole, 3,5-diisopropylpyrazole, 3,5-di-tert-butylpyrazole, 3,5-diphenylpyrazole, butanone oxime, 2-pentanone oxime, cyclohexanone oxime, 4-methyl-2-pentanone oxime, diisopropylamine, N-benzyl-tert-butylamine, ε-caprolactam, or mixtures thereof.

8. 2. The polyisocyanate composition of claim 1, wherein the remainder up to 100% by weight of the total amount of polyisocyanates present in said forming components consists of at least one aliphatic polyisocyanate.

9. The polyisocyanate composition of claim 1, wherein the polyisocyanate composition comprises at least one organic solvent.

10. 10. Use of the polyisocyanate composition according to any one of claims 1 to 9 for the preparation of a one-component system.

11. 10. A one-component system comprising at least one polyisocyanate composition according to any one of claims 1 to 9 and at least one polyol, and optionally further additives.

12. A method for producing a coating on a substrate, comprising applying the one-component system of claim 11 to the substrate and curing at a temperature in the range of 80°C to 300°C.

13. 13. A coating produced or producible by the method of claim 12.

14. 14. A composite comprising the coating of claim 13 and a substrate having a metal and / or plastic surface.