Alicyclic Aljimine Mixture

Abstract

The present invention describes a mixture of aldimine isomers of formulas (Ia), (Ib), and (Ic), in which the ratio of trans,trans-isomer (Ia) to the sum of cis,trans-isomer (Ib) and cis,cis-isomer (Ic) in the mixture is between (5 / 95) and (30 / 70), and its use as a latent curing agent for moisture-cured isocyanate-functional polyurethane compositions. The aldimine isomer mixture of the present invention enables polyurethane compositions with extremely low isophorone diisocyanate monomer content to cure rapidly and provide elastomeric materials with low surface tack and good mechanical properties, particularly in terms of high tensile strength and modulus at high elongation, and excellent stability even under outdoor weather conditions and high UV loads. Such compositions are particularly suitable as elastic adhesives and / or sealants or elastomeric coatings for outdoor applications, such as roofs, floors, or marine applications.

Description

[Technical Field]

[0001] The present invention relates to aldimines and their use as latent curing agents for moisture-cure polyurethanes, particularly for coatings, sealants, and adhesives. [Background technology]

[0002] Aldimines and their use in moisture-cured polyurethane compositions are well known. Aldimines function as so-called latent curing agents or blocked amines. When they come into contact with moisture, they react with isocyanate groups to improve the curing performance of moisture-cured polyurethane compositions, particularly by preventing the formation of bubbles caused by the excessive release of carbon dioxide from the reaction of water with isocyanate groups. Particularly preferred are aldimines that are liquid at room temperature, because they allow for easy handling without solvents.

[0003] In exterior coating, sealing, and adhesive applications, moisture-curing polyurethane compositions typically contain isocyanate-functional polymers based on aliphatic diisocyanates, especially cycloaliphatic isophorone diisocyanate, because they offer particularly good UV resistance. When combined with a latent curing agent, such compositions cure rapidly to form elastomeric materials. However, they often have surfaces that remain somewhat tacky and / or have limited mechanical performance in terms of tensile strength and modulus, are prone to attracting dirt, and / or are prone to degradation under outdoor weather conditions, such as standing water and UV exposure. These effects are particularly pronounced in compositions with relatively low isocyanate content, such as low-modulus sealants and adhesives or coatings based on monomer-reduced polymers. Monomeric isophorone diisocyanate, like other low-molecular-weight isocyanates, is a toxic and volatile molecule, posing a potential health hazard to applicators. Therefore, it is also advantageous from an EH&S point of view to remove it from the isocyanate-functional polymer, for example by distillation.

[0004] The negative effects of low isocyanate content can be mitigated by adding non-monomeric isocyanates, such as isophorone diisocyanate oligomers; however, these also act as crosslinkers, imparting undesirable stiffness and loss of elongation to the cured composition.

[0005] EP 2,132,247 discloses polyurethane compositions based on alicyclic dialdimines from alicyclic isocyanates and polyamines, and ether-aldehydes or ester-aldehydes, but the dialdimine A-4 in the examples is derived from solid bis(4-aminocyclohexyl)methane. U.S. Pat. No. 5,466,771 describes coating compositions based on aldimines from allophanate-containing polyisocyanate oligomers and polyamines, and aliphatic aldehydes, but the aldimine 1 in the examples is derived from bis(4-aminocyclohexyl)methane. The isomeric composition of these aldimines is not specified.

[0006] U.S. Pat. No. 4,020,104 and German Patent No. 4,334,790 describe processes for obtaining the target molecule trans,trans-bis(4-aminocyclohexyl)methane by isomerization and crystallization of the corresponding benzaldimine followed by hydrolysis to separate it from its cis,trans- and cis,cis-isomers. Pure trans,trans-4,4'-di(benzylideneamino)dicyclohexylmethane has a high melting point of 148-150°C. Summary of the Invention [Problem to be solved by the invention]

[0007] The object of the present invention is to overcome the drawbacks of state-of-the-art elastic moisture-cured polyurethane compositions, in particular those having a low isocyanate content, in particular a low content of isophorone diisocyanate monomer, but still limited mechanical properties, in particular tensile strength, elongation, and / or modulus. [Means for solving the problem]

[0008] Surprisingly, this objective is achieved by a mixture of isomers of cycloaliphatic aldimines of formulae (Ia), (Ib), and (Ic), in which the ratio of the trans,trans-isomer (Ia) to the sum of the cis,trans-isomer (Ib) and the cis,cis-isomer (Ic) is in the range of (5 / 95) to (30 / 70), as set forth in claim 1. The aldimine mixture of the present invention is particularly easy to prepare and can be processed without the need for a melting step or the use of solvents, since the cycloaliphatic amine mixture from which the aldimine is derived, and the aldimine mixture itself, are liquid at room temperature. In contrast, mixtures of isomers of benzaldimines of bis(4-aminocyclohexyl)methane are both solid at room temperature and have high melting points. The aldimine isomer mixture of the present invention imparts improved mechanical strength to elastomeric coatings, sealants, or adhesives, especially those based on isophorone diisocyanate. Surprisingly, the tensile strength and / or modulus obtained with the mixtures of aldimine isomers of the present invention are significantly higher than those obtained with aldimines of the same isomers in a different isomeric ratio, in which the trans,trans-isomer of formula (Ia) is more abundant. This is most surprising, since the symmetrical, geometrically elongated trans,trans-isomer would be expected to give polymers with higher strength due to particularly strong hard segment stacking.

[0009] The aldimine isomeric mixture of the present invention makes it possible to formulate moisture-cured polyurethane compositions based on isophorone diisocyanate having a content of less than 0.1% by weight of isophorone diisocyanate monomer, which upon curing form elastomeric materials with low surface tack and good mechanical strength with very high elongation at break. Such compositions are particularly suitable for applications exposed to outdoor weather conditions, such as elastomeric coatings for exterior floors or roofs, or elastomeric adhesives or sealants for heavy UV load applications, such as seam sealants for high-rise facades or deck caulking on ships or boats.

[0010] The aldimine isomer mixture of the present invention has additional advantageous properties: it exhibits good shelf-life stability in isocyanate-functional compositions and allows for low-viscosity compositions that are easy to apply and have sufficient open time to allow precise positioning and application to large surfaces. Nevertheless, the cure process proceeds rapidly, whereby the compositions quickly become largely tack-free and exhibit a rapid onset of mechanical strength and elasticity.

[0011] Further aspects of the invention are set out in the other independent claims. Preferred aspects of the invention are set out in the dependent claims. DETAILED DESCRIPTION OF THE INVENTION

[0012] The subject of the present invention is a mixture of isomers of aldimines of formulae (Ia), (Ib) and (Ic) [ka] wherein each Y is independently a monovalent, linear or branched C3-C alkyl group which may contain ether, ester, tertiary amine, amide, urethane, and / or urea groups. 20 an alkyl, cycloalkyl or arylalkyl group of the formula: A mixture of aldimine isomers, characterized in that the ratio of the trans,trans-isomer (Ia) to the sum of the cis,trans-isomer (Ib) and the cis,cis-isomer (Ic) is within the range of (5 / 95) to (30 / 70).

[0013] As used herein, the term "moisture-curing" refers to compositions that cure when exposed to moisture.

[0014] In this document, the terms "shelf life stability" and "storage stability" refer to the ability of a composition to be stored at room temperature in a suitable moisture-proof container for a period of time, typically several months, without significant change in application performance or end-use performance.

[0015] In this document, the term "molecular weight" refers to the molar mass (g / mol) of a molecule or a portion of a molecule. The term "average molecular weight" refers to the number average molecular weight (M n It is measured by means of gel permeation chromatography (GPC) against polystyrene as standard, in particular with tetrahydrofuran as mobile phase and a refractive index detector.

[0016] In this document, the term "NCO-content" refers to the content of isocyanate groups (in % by weight).

[0017] In this document, the term "wt. %" refers to the mass fraction of a composition component based on the total composition, unless otherwise specified. The terms "weight" and "mass" are used synonymously in this document.

[0018] In this document, "room temperature" refers to a temperature of 23°C.

[0019] All industry codes and standards referenced in this document refer to the latest editions in effect at the time of original filing.

[0020] Preferred are mixtures of aldimine isomers, in which the ratio of trans,trans-isomer (Ia) to the sum of cis,trans-isomer (Ib) and cis,cis-isomer (Ic) is in the range of (15 / 85) to (25 / 75).

[0021] Such mixtures are readily available from mixtures of 4,4'-methylene-bis(cyclohexylamine) isomers having a trans,trans-isomer content in the range of 15-25%, which are liquid at room temperature, such as Amicure® PACM or Vestamin® PACM (Evonik), or Wanamine® H 12 It is commercially available as MDA (manufactured by Wanhua Chem.).

[0022] Y is preferably a branched C3-C7 alkyl, more preferably isopropyl or hept-3-yl, especially isopropyl. Such aldimine isomeric mixtures allow for moisture-curing polyurethane compositions, starting from common aldehydes, that are readily available at low cost and have particularly fast-curing properties.

[0023] More preferably, Y is a group of formula (II): [ka] (In the formula, R 1 and R 2 are the same or different and are C1-C4 alkyl or together form C4-C6 alkylene, and R 5 is H or a C1-C group which may contain one or more ether groups 17 (It is alkyl).

[0024] Such aldimine isomeric mixtures are low in odor and allow for moisture-cured polyurethane compositions with particularly good storage stability, even when they are based on highly reactive aromatic isocyanates such as diphenylmethane diisocyanate (MDI) or toluene diisocyanate (TDI).

[0025] R 1 and R 2 Preferably, both are methyl.

[0026] R 5 is preferably methyl, ethyl, pentyl, heptyl, nonyl, or undecyl.

[0027] R 1 and R 2 are both methyl, and R 5 Most preferably, R is methyl or undecyl. Such isomeric mixtures of aldimines are readily obtainable starting from low-cost aldehydes obtained by esterifying hydroxypivalaldehyde with carboxylic acids such as acetic acid or lauric acid. 5 In the case of R = methyl, after curing, a particularly high modulus and a particularly dry surface can be obtained. 5 In the case of =undecyl, compositions with particularly low odor are possible.

[0028] It is most preferred that Y is a group of formula (III): [ka] (In the formula, R 1 and R 2 are the same or different and are C1-C4 alkyl or together form C4-C6 alkylene, and R 3 and R 4 are the same or different and are C1-C8 alkyl optionally containing ether oxygen, or taken together form C4-C6 alkylene optionally containing ether oxygen).

[0029] Such aldimine isomer mixtures allow for moisture-cure polyurethane compositions with low odor and fast cure performance, which are primarily based on cycloaliphatic isocyanates such as isophorone diisocyanate (IPDI) or perhydro-4,4'- or 2,4'-diphenylmethane diisocyanate (H 12 It is particularly suitable for use in compositions based on methyl methyl ether (MDI or HMDI).

[0030] R 1 and R 2 Preferably, both are methyl.

[0031] Preferably, R 3 and R 4 are both methoxyethyl groups or together form a 3-oxa-1,5-pentylene or 2,4-dimethyl-3-oxa-1,5-pentylene group, which is 3 and R 4 together with the nitrogen atom to which it is attached to form a morpholine or 2,6-dimethylmorpholine ring.

[0032] R 3 and R 4 Most preferably, together form a 3-oxa-1,5-pentylene group, which is part of a morpholine ring.

[0033] R 1 and R 2 are both methyl, and R 3 and R 4 Most preferably, these aldimine isomers are combined to form a 3-oxa-1,5-pentylene group, which is part of the morpholine ring. This mixture of aldimine isomers is liquid at room temperature, making it particularly easy to manufacture and process. It allows for moisture-cured polyurethane compositions based primarily on cycloaliphatic isocyanates to be produced that are particularly low in odor, have particularly good shelf-life stability, rapid cure, and high mechanical strength and elasticity.

[0034] Preferably, Y is selected from the group consisting of branched C3-C7 alkyl, a group of formula (II), and a group of formula (III).

[0035] It is preferred that Y is the same substituent in formulae (Ia), (Ib) and (Ic).

[0036] The mixture of isomers of isomeric aldimines of formulae (Ia), (Ib), and (Ic) of the present invention is preferably prepared by a condensation reaction between a mixture of isomers of amines of formulae (IVa), (IVb), and (IVc), in which the ratio of trans,trans-isomers to the sum of cis,trans-isomers and cis,cis-isomers is in the range of (5 / 95) to (30 / 70), and at least one aldehyde of formula (V): [ka] [In formula (V), Y has the meaning explained above].

[0037] The stoichiometric ratio between the aldehyde of formula (V) and the amine groups of the mixture of isomers of amines of formulas (IVa), (IVb) and (IVc) is preferably at least 1, with the aim of converting all the amine groups.

[0038] The condensation reaction is preferably carried out at a temperature in the range of 15 to 120° C., preferably 20 to 100° C. The water released by the condensation reaction is preferably removed from the reaction product, for example as an azeotrope with a suitable solvent, or preferably by distillation without using a solvent.

[0039] The condensation reaction is preferably carried out in the absence of a solvent and the water is removed from the reaction product by vacuum distillation, which can be used as the mixture of aldimine isomers of the present invention without further purification.

[0040] The mixture of isomers of amines of formulae (IVa), (IVb) and (IVc) having a ratio of trans,trans-isomer to the sum of cis,trans-isomer and cis,cis-isomers ranging from (5 / 95) to (30 / 70) is preferably a grade of 4,4'-methylene-bis(cyclohexylamine) having a trans,trans-isomer content ranging from 15 to 25%, which is liquid at room temperature, such as Amicure® PACM or Vestamin® PACM (Evonik) or Wanamine® H 12 It is commercially available as MDA (manufactured by Wanhua Chem.).

[0041] Preferred aldehydes of formula (V) are isobutyraldehyde, 2-ethylhexanal, 2,2-dimethyl-3-di(methoxyethyl)aminopropanal, 2,2-dimethyl-3-(N-2,6-dimethylmorpholino)propanal, 2,2-dimethyl-3-(N-morpholino)propanal, 2,2-dimethyl-3-acetoxypropanal, or 2,2-dimethyl-3-lauroyloxypropanal.

[0042] Particularly preferred are aldehydes selected from the group consisting of isobutyraldehyde, 2,2-dimethyl-3-(N-morpholino)propanal, 2,2-dimethyl-3-(N-(2,6-dimethyl)morpholino)propanal, 2,2-dimethyl-3-acetoxypropanal, and 2,2-dimethyl-3-lauroyloxypropanal. Most preferred is 2,2-dimethyl-3-(N-morpholino)propanal.

[0043] Particularly preferred are mixtures of isomers of aldimines of the invention selected from the group consisting of N,N'-bis(isobutylidene)-4,4'-methylene-bis(cyclohexylamine), N,N'-bis(2,2-dimethyl-3-(N-morpholino)propylidene)-4,4'-methylene-bis-(cyclohexylamine), N,N'-bis(2,2-dimethyl-3-(N-(2,6-dimethyl)morpholino)propylidene)-4,4'-methylene-bis(cyclohexylamine), N,N'-bis(2,2-dimethyl-3-acetoxypropylidene)-4,4'-methylene-bis(cyclohexylamine), and N,N'-bis(2,2-dimethyl-3-lauroyloxypropylidene)-4,4'-methylene-bis(cyclohexylamine). Most preferred is N,N'-bis(2,2-dimethyl-3-(N-morpholino)propylidene)-4,4'-methylene-bis(cyclohexylamine).

[0044] The mixture of aldimine isomers of the present invention may contain minor amounts of aldimines of formula (VI): [ka] (wherein Y has the meaning previously explained).

[0045] The mixture of isomeric aldimines of the invention may further contain proportions of the corresponding 2,4'- and / or 2,2'-isomers, in particular the 2,4'-isomers of the formula: [ka] (wherein Y has the meaning explained above). The ratio of the sum of the 2,4'- and 2,2'-isomers to the mixture of isomers of the aldimine of the present invention (i.e., the 4,4'-isomer) is preferably less than 20 / 80, in particular 10 / 90 or less. In a preferred embodiment, it is in the range of (0 / 100) to (2 / 98). Furthermore, in a particularly preferred embodiment, it is in the range of (5 / 95) to (10 / 90).

[0046] A further object of the present invention is the use of the mixture of isomers of aldimines of formulae (Ia), (Ib) and (Ic) according to the invention as latent curing agents for moisture-cured polyurethane compositions.

[0047] Such moisture-curing polyurethane compositions preferably include polyisocyanates and / or isocyanate-functional polymers based on commercially available diisocyanate monomers, such as diphenylmethane diisocyanate (MDI), in particular 4,4'-diphenylmethane diisocyanate, which may contain some 2,4'- and / or 2,2'-diphenylmethane diisocyanate, toluene diisocyanate (TDI), preferably, which may contain some 2,6-toluene diisocyanate. 2,4-toluene diisocyanate, 1,4-phenylene diisocyanate (PDI), naphthalene-1,5-diisocyanate (NDI), 1,6-hexane diisocyanate (HDI), 2,2(4),4-trimethyl-1,6-hexamethylene diisocyanate (TMDI), cyclohexane-1,3- or -1,4-diisocyanate, isophorone diisocyanate (IPDI), methyl-diisocyanatocyclohexane (H6TDI or HTDI), perhydro-4,4'-diphenylmethane diisocyanate (H 12 MDI or HMDI), 1,3- or 1,4-bis(isocyanatomethyl)cyclohexane, m- or p-xylene diisocyanate (XDI), or m-tetramethylxylene diisocyanate (TMXDI).

[0048] Among them, MDI, TDI, HDI, or IPDI is preferred.

[0049] MDI or TDI are particularly preferred in combination with the mixture of aldimine isomers of the present invention, where Y is a group of formula (II).

[0050] IPDI is particularly preferred in combination with the mixture of isomeric aldimines of the present invention, where Y is a group of formula (III) or is a branched C3-C7 alkyl.

[0051] It is preferred to use mixtures of isomers of aldimines of formulae (Ia), (Ib) and (Ic) according to the invention in combination with at least one further aldimine of formula (VII): [ka] (In the formula, n is 2 or 3; A is the residue of a diamine or triamine after removal of the amine groups, wherein the diamine or triamine is selected from the group consisting of hexane-1,6-diamine, 2-methylpentane-1,5-diamine, 3-aminomethyl-3,5,5-trimethylcyclohexylamine (isophoronediamine), 4(2)-methylcyclohexane-1,3-diamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)benzene, 1,2-diaminocyclohexane, an average molecular weight M in the range of 200 to 4,000 g / mol; n and an average molecular weight M in the range of 380 to 5,000 g / mol. n Polyoxypropylene triamine having the formula and Y has the meaning previously explained).

[0052] It is preferred that Y is the same substituent in formulae (Ia), (Ib) and (Ic) and in formula (VII).

[0053] Particularly preferred is a combination with an aldimine of formula (VII) where A is the residue after removal of the amine group of 3-aminomethyl-3,5,5-trimethylcyclohexylamine and Y is isopropyl in formulas (Ia), (Ib), (Ic) and (VII). Such mixtures are particularly preferred for use in primers, paints or varnishes.

[0054] Further particularly preferred is the combination with an aldimine of formula (VII), in which A is the residue of 3-aminomethyl-3,5,5-trimethylcyclohexylamine after removal of the amine group, and Y is a radical of formula (III) in formulas (Ia), (Ib), (Ic) and (VII), preferably in which R 1 and R 2 are both methyl, and R 3 and R 4 together form a 3-oxa-1,5-pentylene group. Such mixtures are particularly preferred for use in elastomeric adhesives, sealants, or coatings, especially those based on isophorone diisocyanate.

[0055] Preferably, the weight ratio between the mixture of isomers of aldimines of formulae (Ia), (Ib), and (Ic) of the present invention and the aldimine of formula (VII) is within the range of (10 / 90) to (80 / 20), preferably (20 / 80) to (75 / 25), more preferably (30 / 70) to (70 / 30), and most preferably (40 / 60) to (60 / 40). Such a mixture can be used as a latent curing agent, particularly with low viscosity and low solidification temperature, to produce low-cost moisture-cured polyurethane compositions with high tensile strength and / or modulus, which are significantly higher than those obtained when the aldimine of formula (VII) is used alone.

[0056] A further subject of the present invention is a moisture-curing polyurethane composition comprising: - an isocyanate-functional polymer obtained by reacting at least one polyisocyanate and / or at least one diisocyanate monomer with at least one polyol, and - mixtures of isomers of aldimines of formulae (Ia), (Ib) and (Ic) according to the invention.

[0057] Preferably, the polyisocyanate is an oligomeric or polymeric derivative of at least one diisocyanate monomer, preferably selected from the group consisting of MDI, TDI, HDI, and IPDI.

[0058] Among them, preferred are carbodiimides or uretonimines of MDI, polymeric MDI, oligomeric TDI, biurets or isocyanurates or uretdiones or iminooxadiazinediones or allophanates of HDI, isocyanurates of IPDI, or mixed isocyanurates based on TDI and HDI.

[0059] Preferably, the isocyanate-functional polymer obtained by reaction of at least one diisocyanate monomer with at least one polyol has an NCO-content in the range of 1 to 10% by weight, preferably 1.5 to 8% by weight.

[0060] The isocyanate-functional polymer has an average molecular weight M in the range of 800 to 15,000 g / mol, preferably 1,000 to 12,000 g / mol. n It is preferred that the ion exchange resin has the following structure:

[0061] The diisocyanate monomer for the isocyanate-functional polymer is preferably selected from the group consisting of: 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,3,5,6- Tetramethyl-1,4-diisocyanatobenzene, naphthalene-1,5-diisocyanate, 3,3'-dimethyl-4,4'-diisocyanatodiphenyl, 1,4-tetramethylene diisocyanate, 2-methylpentamethylene-1,5-diisocyanate, 1,6-hexamethylene diisocyanate (HDI), 2,2(4),4-trimethyl-1,6-hexamethylene diisocyanate, 1,10-decamethylene diisocyanate, 1,12-diisocyanate Decamethylene diisocyanate, lysine diisocyanate, lysine ester diisocyanate, cyclohexane-1,3-diisocyanate, cyclohexane-1,4-diisocyanate, 1-methyl-2,4-diisocyanatocyclohexane, 1-methyl-2,6-diisocyanatocyclohexane, isophorone diisocyanate (IPDI), perhydro-4,4'-diphenylmethane diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane cyclohexane, 1,4-bis-(isocyanatomethyl)cyclohexane, m-xylylene diisocyanate, p-xylylene diisocyanate, tetramethyl-1,3-xylylene diisocyanate, tetramethyl-1,3-xylylene diisocyanate, bis-(1-isocyanato-1-methylethyl)naphthalene, and 3,6-bis-(9-isocyanatononyl)-4,5-di(1-heptenyl)cyclohexene (dimer acid diisocyanate).

[0062] Among these, preferred are diphenylmethane diisocyanate (MDI), particularly 4,4'-diphenylmethane diisocyanate, or a mixture thereof with 2,4'-diphenylmethane diisocyanate and / or 2,2'-diphenylmethane diisocyanate, TDI, particularly 2,4-toluene diisocyanate, or a mixture thereof with 2,6-toluene diisocyanate, HDI, or IPDI.

[0063] Particularly preferred is IPDI. In such compositions, the mixture of aldimine isomers according to the invention is capable of rapid curing to non-tacky, elastic materials having particularly good mechanical properties, in particular in terms of tensile strength, elongation and / or modulus.

[0064] The aldimine isomer mixture of the present invention is particularly useful in IPDI-based polyurethane compositions containing less than 0.2 wt. % isophorone diisocyanate monomer, particularly less than 0.1 wt. % isophorone diisocyanate monomer, based on the total composition. Such IPDI-based polyurethane compositions with low monomer content, when prepared without aldimine or using other types of aldimines, tend to cure slowly or insufficiently, resulting in sticky surfaces and poor mechanical strength and durability. The aldimine mixture of the present invention can largely overcome these drawbacks.

[0065] The polyol is preferably selected from the group consisting of polyether polyols, polyester polyols, polycarbonate polyols, and polyacrylate polyols.

[0066] The isocyanate-functional polymer is preferably a liquid at room temperature.

[0067] A low viscosity is preferable, and a cone-plate viscometer (cone diameter: 25 mm, cone angle: 1°, cone-plate distance: 0.05 mm, shear rate: 10 s -1Preferably, the isocyanate-functional polymer has a viscosity, measured at 20°C, of ​​less than 50 Pa·s, more preferably less than 30 Pa·s, especially less than 20 Pa·s.

[0068] The polyol is preferably a polyether polyol or a mixture of at least one polyether polyol with at least one further polyol selected from polyester polyols, polycarbonate polyols, and polyacrylate polyols.

[0069] Preferably, the polyether polyol has repeating units selected from 1,2-ethyleneoxy, 1,2-propyleneoxy, 1,3-propyleneoxy, 1,2-butyleneoxy, and 1,4-butyleneoxy. Particularly preferred are 1,2-propyleneoxy units, optionally incorporating some 1,2-ethyleneoxy units at the chain ends. Even more particularly preferred are 1,4-butyleneoxy units.

[0070] Preferred are polyether polyols having an unsaturation content of less than 0.02 mEq / g, preferably less than 0.01 mEq / g.

[0071] Preferred are polyoxypropylene diols or triols, optionally ethylene oxide-endcapped, having an OH number in the range of 10 to 250 mg KOH / g, preferably 20 to 125 mg KOH / g.

[0072] Preferably, the polyol has an average OH functionality in the range of 1.7-3.

[0073] Particularly preferred are optionally ethylene oxide-endcapped ethylene glycol esters having an average molecular weight M in the range of 450 to 12,000 g / mol, preferably 1,000 to 6,000 g / mol. n It is a polyoxypropylene diol having the formula:

[0074] Particularly preferred are further optionally ethylene oxide-endblocked copolymers having an average molecular weight M in the range of 3,000 to 8,000 g / mol. n It is a polyoxypropylene triol started with trimethylolpropane or glycerin, having the formula:

[0075] Preference is further given to hydroxybenzoates having an OH number in the range of 50 to 180 mg KOH / g and an average molecular weight M in the range of 650 to 2,000 g / mol. n The poly(oxy-1,4-butylene)diol has the formula:

[0076] Particularly preferred isocyanate-functional polymers have an NCO-content in the range of 5-6% by weight, an OH number in the range of 110-115 mg KOH / g and an average molecular weight M of about 1,000 g / mol. n It is obtained from a polyoxypropylene diol having the formula:

[0077] Another particularly preferred isocyanate-functional polymer has an NCO-content in the range of 1.7 to 2% by weight, an OH number in the range of 26 to 30 mg KOH / g and an average molecular weight M of about 4,000 g / mol. n It is obtained from a polyoxypropylene diol having the formula:

[0078] Another particularly preferred isocyanate-functional polymer has an NCO-content in the range of 1.7 to 2.5 wt. %, is optionally ethylene oxide-endblocked, an OH number in the range of 26 to 37 mg KOH / g, and an average molecular weight M in the range of 4,500 to 6,000 g / mol. n It is obtained from polyoxypropylene triol having the formula:

[0079] Another particularly preferred isocyanate-functional polymer is one obtained from a poly(oxy-1,4-butylene)diol having an NCO-content in the range of 2.8 to 7.7% by weight and an OH value in the range of 55 to 175 mg KOH / g.

[0080] Preferably, the isocyanate-functional polymer has an NCO-content in the range of 1 to 10% by weight and is obtained from at least one polyether polyol.

[0081] The isocyanate-functional polymer is preferably prepared by combining at least one diisocyanate monomer with at least one polyol in an NCO / OH molar ratio of at least 1.3, preferably at least 1.5, more preferably at least 1.8, in the absence of moisture, at a temperature in the range of 20 to 160°C, preferably 40 to 140°C, optionally in the presence of a suitable catalyst.

[0082] Particularly preferred isocyanate-functional polymers have a diisocyanate monomer content of less than 0.5 wt.%, preferably less than 0.3 wt.%, and more preferably less than 0.2 wt.%, based on the total polymer. Such low-monomer isocyanate-functional polymers allow for the formulation of curable compositions having a total diisocyanate monomer content of less than 0.1 wt.%, based on the total composition, that are safe and can be used without special protective measures or hazard labeling.

[0083] For such polymers, it is preferred to carry out the reaction at an NCO / OH molar ratio of at least 3 / 1, followed by a distillation process to remove most of the remaining diisocyanate monomer.

[0084] The NCO / OH molar ratio is preferably within the range of 3 / 1 to 10 / 1, more preferably 3 / 1 to 8 / 1.

[0085] After reaction, the remaining diisocyanate monomer is removed from the reaction mixture using a distillation process, preferably thin film or short path distillation under vacuum.

[0086] Particularly preferred is a multi-stage process in which the diisocyanate monomer is removed in a short-path evaporator at a jacket temperature in the range of 120-200°C, preferably 140-180°C, and a pressure of 0.001-0.5 mbar.

[0087] The reaction of the diisocyanate monomer with the polyol, as well as the removal of any remaining diisocyanate monomer, is preferably carried out in the absence of a solvent or entrainer.

[0088] Preferred such low monomer content isocyanate functional polymers are those based on isophorone diisocyanate.

[0089] Particularly preferred are low-monomer isocyanate-functional polymers having a content of isophorone diisocyanate monomer of less than 0.3% by weight, preferably less than 0.2% by weight, based on the total composition, and an NCO content in the range of 1 to 8% by weight, which are obtained by reacting isophorone diisocyanate with at least one polyether polyol having an OH number in the range of 13 to 180 mg KOH / g, in an NCO / OH molar ratio in the range of 3 / 1 to 10 / 1, followed by removal of most of the isophorone diisocyanate monomer by a distillation process.

[0090] The polyurethane composition may include one or more isocyanate-functional polymers, especially one or more of the polymers of the preferred embodiments.

[0091] Preferably, the moisture-cured polyurethane composition contains less than 0.1% by weight of diisocyanate monomers based on the total composition, allowing safe use by the applicator without special protective measures and without the need for hazard labeling.

[0092] Preferably, the polyurethane composition comprises at least one further component selected from the group consisting of a latent curing agent different from the aldimine of formula (I), an oligomeric polyisocyanate, a filler, a plasticizer, a catalyst, and a stabilizer.

[0093] Preferred such latent hardeners are aldimines other than oxazolidines, bis-oxazolidines, or mixtures of isomers of aldimines of the present invention.

[0094] Preferred aldimines which are different from the aldimines of formula (I) are the aldimines of formula (VII).

[0095] It is preferred that Y is the same substituent in formulae (Ia), (Ib) and (Ic) and in formula (VII).

[0096] Preferably, the polyurethane composition further comprises at least one aldimine of formula (VIIa): [ka] where Y has the meaning previously explained. This aldimine is obtained from isophoronediamine and allows for particularly low-cost compositions with low viscosity and good mechanical properties.

[0097] Preferably, the weight ratio between the mixture of isomers of aldimines of formulae (Ia), (Ib), and (Ic) of the present invention and the aldimine of formula (VIIa) is in the range of (10 / 90) to (80 / 20), preferably (20 / 80) to (75 / 25). Such compositions exhibit improved mechanical strength compared to the use of aldimine of formula (VIIa) alone.

[0098] Preferably, the polyurethane composition further comprises at least one aldimine of formula (VIIb): [ka] [Wherein, T is the average molecular weight M in the range of 380 to 500 g / mol] n and Y has the meaning previously explained.

[0099] Preferably, the weight ratio between the mixture of isomers of aldimines of formulae (Ia), (Ib) and (Ic) of the present invention and the aldimine of formula (VIIb) is within the range of (30 / 70) to (80 / 20), preferably (40 / 60) to (70 / 30).

[0100] In a particularly preferred embodiment of the present invention, the composition comprises at least one aldimine of formula (VIIa) and at least one aldimine of formula (VIIb). Preferably, the weight ratio between the mixture of isomers of aldimines of formulae (Ia), (Ib), and (Ic) of the present invention, the aldimine of formula (VIIa), and the aldimine of formula (VIIb) is in the range of (15-45) / (20-50) / (20-50), where the sum of the three numbers is equal to 100.

[0101] The polyurethane composition preferably further comprises at least one oligomeric diisocyanate, preferably an oligomer of HDI and / or IPDI, particularly an isocyanurate of isophorone diisocyanate. Such oligomeric diisocyanates can help achieve high strength. However, their use is somewhat limited because using too much can dramatically increase stiffness while simultaneously reducing elongation and making the overall composition brittle.

[0102] Suitable fillers are: ground or precipitated calcium carbonate (chalk) (optionally surface-coated with a fatty acid such as stearate), barium sulfate (baryte), slate, silicates (quartz), magnesiosilicates (talc) or alumosilicates (clay, kaolin), dolomite, mica, glass bubbles, silicic acid, especially highly dispersed silicic acid from pyrolysis processes (fumed silica), carbon black, microspheres, pigments, especially titanium dioxide or iron oxide, or flame-retardant fillers such as aluminum hydroxide, especially aluminum trihydroxide (ATH), magnesium dihydroxide, antimony trioxide, antimony pentoxide, boric acid, zinc borate, zinc phosphate, melamine borate, melamine cyanurate, ethylenediamine phosphate, ammonium polyphosphate, dimelamine orthophosphate, dimelamine pyrophosphate, hexabromocyclododecane, decabromodiphenyl oxide, and tris(bromoneopentyl)phosphate.

[0103] Preferred fillers are chalk, barytes, fumed silica and / or ATH.

[0104] Suitable plasticizers are: phthalates, in particular diisononyl phthalate (DINP) or diisodecyl phthalate (DIDP), hydrogenated phthalates, in particular hydrogenated DINP (which is diisononyl-1,2-cyclohexanedicarboxylate (DINCH)), terephthalates, in particular bis(2-ethylhexyl) terephthalate or diisononyl terephthalate, hydrogenated terephthalates, in particular bis(2-ethylhexyl)-1,4-cyclohexanedicarboxylate, trimellitates, adipates, in particular dioctyl adipate (DOA), azelates, sebacates, citrates, benzoates, glycol ethers, glycol esters, organic sulfonates or phosphates, in particular diphenylcresyl phosphate (DPK), polybutene, polyisobutene, or plasticizers derived from natural fats or oils, such as epoxidized soybean or linseed oil.

[0105] Suitable catalysts for accelerating the hydrolysis of aldimines are acid catalysts, in particular carboxylic acids or sulfonic acids, preferably aromatic carboxylic acids such as benzoic acid or salicylic acid.

[0106] Suitable catalysts for accelerating the reaction of isocyanate groups are metal catalysts, preferably dialkyltin complexes, in particular dibutyltin or dioctyltin carboxylates or acetoacetonates, such as dibutyltin dilaurate (DBTDL), DBT(acac)2 or DOTDL, or amine catalysts, preferably tertiary amino ethers, in particular 2,2'-dimorpholinodiethyl ether (DMDEE).

[0107] Preferred stabilizers are UV stabilizers and / or heat stabilizers, especially UV absorbers such as 2-cyano-3,3-diphenylacrylic acid ethyl ester, or hindered amine light stabilizers (HALS), such as bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate.

[0108] The polyurethane composition may further include the following components: - other isocyanate-functional polyurethane polymers; isocyanate-functional compounds obtained from small diols, such as 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol or diethylene glycol, in particular from 1,4-butanediol; organic solvents, in particular acetone, methyl ethyl ketone, methyl n-propyl ketone, diisobutyl ketone, methyl isobutyl ketone, methyl n-amyl ketone, methyl isoamyl ketone, acetylacetone, mesityl oxide, cyclohexanone, methylcyclohexanone, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, tert-butyl acetate, 1-methoxy-2-propyl acetate, n-butyl propionate, ethyl-3-ethoxy propionate, diethyl malonate, diisopropyl ether, dibutyl ether, ethylene glycol diethyl ether, ethylene glycol monopropyl ether, ethylene glycol mono-2 -ethylhexyl ether, diethylene glycol diethyl ether, propylal, butyral, 2-ethylhexylal, dioxolane, glycerol formal, 2,5,7,10-tetraoxaundecane (TOU), toluene, xylene, heptane, octane, diisopropylnaphthalene, petroleum fractions such as naphtha, white spirit, or petroleum ethers such as Solvesso™ solvents (manufactured by Exxon), hydrogenated naphtha, methylene chloride, propylene carbonate, dimethyl carbonate, butyrolactone, N-methyl-pyrrolidone, N-ethyl-pyrrolidone, p-chlorobenzotrifluoride, or benzotrifluoride; fibres, in particular glass, carbon, metal, ceramic or plastic fibres, in particular polyamide or polyethylene fibres, or natural fibres, such as wool, cellulose, hemp or sisal; - nanofillers such as graphene or carbon nanotubes; - dye; desiccants, in particular molecular sieves, calcium oxide, highly reactive isocyanates such as p-tosylisocyanate, monooxazolidines such as Incozol® 2 (Incorez), or orthoformates; adhesion promoters, in particular organoalkoxysilanes such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, (meth)acrylosilanes, anhydridosilanes, carbamatosilanes, alkylsilanes or iminosilanes, or their oligomers or titanates; thickening agents, such as bentonite, derivatives of castor oil, hydrogenated castor oil, polyamides, polyamide waxes, polyurethanes, urea compounds, fumed silica, cellulose ethers or hydrophobically modified polyoxyethylene; - natural resins, fats or oils, such as rosin, shellac, linseed oil, castor oil or soybean oil; non-reactive polymers, in particular homopolymers or copolymers of unsaturated monomers, in particular ethylene, propylene, butylene, isobutylene, isoprene, vinyl acetate or alkyl (meth)acrylates, preferably polyethylene (PE), polypropylene (PP), polyisobutylene, ethylene-vinyl acetate copolymer (EVA) or atactic poly-α-olefins (APAO); Additives such as wetting agents, flow promoters, levelling agents, antifoaming agents, defoamers, stabilizers, antioxidants or biocides.

[0109] The composition preferably contains the isocyanate-functional polymer in an amount ranging from 15 to 80% by weight, particularly from 20 to 50% by weight, based on the total composition.

[0110] The composition preferably contains a mixture of isomers of aldimines of formulae (Ia), (Ib) and (Ic) of the present invention in an amount ranging from 0.5 to 25% by weight, preferably from 1 to 20% by weight, based on the total composition.

[0111] The composition preferably contains an amount of aldimine such that the ratio of the total number of aldimine groups to the total number of isocyanate groups is in the range of 0.3-1, preferably 0.4-1, more preferably 0.5-1.

[0112] The composition preferably contains a plasticizer in an amount ranging from 0 to 40% by weight, preferably from 10 to 30% by weight, based on the total composition.

[0113] The composition preferably contains a filler in an amount ranging from 0 to 80% by weight, preferably from 20 to 60% by weight, based on the total composition.

[0114] In a preferred embodiment of the present invention, the composition further comprises at least one flame-retardant component, preferably a flame-retardant filler and / or a flame-retardant plasticizer. Such compositions are particularly preferred as coatings for waterproofing buildings, especially roofs.

[0115] A preferred flame-retardant filler is aluminum trihydroxide (ATH). A preferred flame-retardant plasticizer is diphenylcresyl phosphate (DPK).

[0116] Particularly preferred compositions include at least one trimer of 1,6-hexamethylene diisocyanate or isophorone diisocyanate and at least one aluminum trihydroxide filler. Such compositions are particularly preferred as coatings for waterproofing buildings.

[0117] In one embodiment of the present invention, the composition preferably contains a small amount of a volatile organic solvent having a boiling point of less than 200° C. at atmospheric pressure. Preferably, it contains 200 g or less of a volatile organic solvent having a boiling point of less than 200° C. at atmospheric pressure, more preferably 150 g or less of such an organic solvent per liter of the total composition. Such a composition is particularly suitable as a coating, particularly for waterproofing buildings, or as an exterior flooring material.

[0118] In a further embodiment of the invention, the composition preferably comprises an even lower amount of a volatile organic solvent having a boiling point at atmospheric pressure below 200° C., preferably less than 10% by weight, more preferably less than 5% by weight, and most preferably less than 1% by weight, based on the total composition. Such compositions are particularly suitable as adhesives, joint fillers, or exterior flooring materials.

[0119] In a further embodiment of the present invention, the composition contains a large amount of a volatile organic solvent, preferably in the range of 20 to 98% by weight, more preferably 30 to 80% by weight, based on the total composition. Such compositions are particularly suitable as primers or coatings, particularly paints or varnishes. They contain, in particular, a mixture of isomers of the aldimine of the present invention, in which Y is a branched C3-C7 alkyl, preferably isopropyl. This allows for particularly rapid curing.

[0120] The moisture-cure polyurethane composition is preferably formulated as a single-pack composition prepared as a macroscopically homogeneous fluid or paste by mixing all components under moisture exclusion and stored at ambient temperature in a moisture-tight container. Suitable moisture-tight containers are preferably made of optionally coated metal or plastic. They are preferably buckets, barrels, hob, bags, sausages, cartridges, cans, bottles, or cylinders. With proper packaging and storage, the one-component moisture-cure polyurethane composition exhibits good shelf-life stability.

[0121] The moisture-curing polyurethane composition can also be formulated as a two-pack composition, in which the curing agent and isocyanate components are stored separately in separate containers and mixed immediately before or during application. The isocyanate component includes all components having isocyanate groups and, optionally, additional components that do not react with isocyanate groups, and the curing agent component includes isocyanate-reactive components and, optionally, additional components. Preferably, the curing agent component includes a polyol and / or a chain extender, and the isocyanate component includes a polyisocyanate. The aldimine isomer mixture of the present invention can be part of the curing agent and / or the isocyanate component, but is preferably part of the curing agent component.

[0122] Suitable polyols are: polyether polyols, preferably those mentioned above, polyester polyols, polycarbonate polyols, copolymers of polyether, polyester and / or polycarbonate polyols, poly(meth)acrylate polyols, polybutadiene polyols, natural oil-based polyols, or fatty acid or dimer fatty acid-based polyols. Preferred chain extenders are: 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, or diethylene glycol.

[0123] The curing process begins when the moisture-curing composition is applied and comes into contact with moisture, particularly atmospheric moisture. During curing, isocyanate groups react with hydrolyzed aldimine groups under the influence of moisture. Additional isocyanate groups, particularly those present in excess relative to the aldimine groups, react with each other under the influence of moisture. As a result of these reactions, the composition cures to form an elastic material. During the curing reaction, an aldehyde of formula (V) is released.

[0124] Depending on the substituent Y, the aldehyde may be volatile and evaporate from the applied composition within a period of time, or it may have low volatility and some or most of it may remain in the cured composition.

[0125] Another subject of the invention is a cured composition, which is obtained from a moisture-cured polyurethane composition after it has been contacted with moisture.

[0126] The moisture for curing the composition is preferably atmospheric moisture that has penetrated into the composition from the surrounding air via a diffusion process. Upon curing, a thin skin of cured composition initially forms on the surface of the applied composition, which continuously increases in thickness as the curing process progresses until all of the applied composition is cured. Additional moisture contributing to the curing process may come from the substrate to which the composition is applied and / or from water-containing or water-releasing accelerator ingredients that are mixed into the composition or sprayed or brushed onto the surface of the applied composition before or during application.

[0127] The moisture-cured polyurethane composition is preferably applied under ambient conditions, preferably in the temperature range of -10 to 50°C, more preferably -5 to 45°C, especially 0 to 40°C.

[0128] Curing of the composition is also preferably carried out at ambient conditions.

[0129] The moisture-cure polyurethane composition has sufficient open time to allow precise positioning and application to large surfaces and rapid cure progression whereby the composition is quickly tack-free and exhibits a rapid onset of mechanical strength and elasticity.

[0130] "Open time" is the time interval during which the applied composition can be processed or reprocessed without any adverse effects. It ends when the viscosity of the composition increases too much as a result of curing, or at the latest when a skin forms on the surface. The time until a skin forms on the surface is called the "skin formation time" or "skinning time."

[0131] The moisture-curing polyurethane composition is preferably used as an elastic adhesive and / or sealant, as an elastic coating, or as a primer, paint, or varnish.

[0132] As an elastic adhesive and / or sealant, the composition is particularly suitable for use in the construction or manufacturing industry or in vehicle manufacturing, in particular for gluing, assembling or bonding modules, or as a sealant and caulking of joints or cavities, for example for high-rise facades or ship decks exposed to particularly high UV loads.

[0133] As elastic coatings, the compositions are particularly suitable for sealing and protecting buildings or parts of buildings, such as footbridges, balconies, terraces, roofs, especially flat or slightly sloped roofs, roof gardens, or inside buildings, under ceramic tiles in wet rooms or kitchens, or in cesspits, trenches, shafts, silos, tanks or wastewater treatment plants.

[0134] It can also be used for repair purposes, especially for damaged roofing membranes, flooring, or sprayed membranes.

[0135] As a primer, the composition typically contains more than 50% by weight of a volatile organic solvent and is preferably a one- or two-component composition, which is particularly suitable for pretreating a substrate to enhance the strength and adhesion of a subsequent layer, particularly a coating, sealant, or adhesive.

[0136] As a paint or varnish, the composition typically contains more than 20% by weight of a volatile organic solvent and is preferably a two-component composition, which is particularly suitable for coating substrates with a highly aesthetic, hard, tough, scratch-resistant, abrasion-resistant, and chemical-resistant finish.

[0137] The moisture-cure polyurethane composition may be formulated so that it has a paste-like consistency with pseudoplastic properties, and is preferably applied in the form of beads having, for example, a round or triangular cross-sectional shape from a cartridge, barrel, or hob.

[0138] The moisture-curing polyurethane composition may be further formulated so that it has a fluid consistency with self-leveling properties, possibly with slight thixotropy. Such compositions may be applied by spraying or pouring onto flat or slightly inclined surfaces. To form a smooth coating, the composition may then be spread to the desired layer thickness, optionally using a suitable tool such as a squeegee, toothed trowel, spatula, roller, brush, or drawdown bar. Typically, a layer thickness of 0.5 to 3 mm, preferably 0.5 to 2 mm, is applied in one step.

[0139] Furthermore, suitable substrates to which the composition may typically be applied include, among others: - concrete, lightweight concrete, mortar, cement, fibre cement, brick, adobe, tile, slate, gypsum, gypsum panels or natural stone, such as granite or marble; - glass or glass ceramic; - repair or levelling compounds based on PCC (polymer modified cement) or ECC (epoxy modified cement); - Metals and alloys, for example aluminium, copper, iron, steel, non-ferrous metals (including surface-finished metals and alloys, for example galvanised or chrome-plated metals); - Asphalt; - Asphalt felt; - plastics, such as rigid or flexible PVC, polycarbonate, polystyrene, polyester, polyamide, PMMA, ABS, SAN, epoxide resins, phenolic resins, PUR, POM, TPO, PE, PP, EPM or EPDM (in untreated form or with a surface treatment by means of plasma, corona or flame); - fiber-reinforced plastics, such as carbon fiber-reinforced plastics, glass fiber-reinforced plastics, or sheet moulding compounds; - wood or plywood, paper, paperboard, wood materials glued together with organic resins, resin-fabric composites or so-called polymer composites; - Heat insulating foams, especially those made from EPS, XPS, PUR, PIR, rock wool, glass wool or foam glass; - Coated substrates, such as varnished tiles, painted concrete, coated metals or varnished metal sheets.

[0140] These substrates are optionally pretreated before the composition is applied, in particular by physical and / or chemical cleaning processes or by applying an activator or primer.

[0141] It is possible to bond or seal two identical substrates or two different substrates.

[0142] Another subject of the present invention is an elastomeric coating, adhesive, or sealant comprising a cured composition as described above.

[0143] Another subject of the invention is a primer, paint or varnish comprising a cured composition as described above.

[0144] The elastic adhesive or sealant is preferably used to provide elastic bonding, preferably by a method comprising the steps of: (i) a moisture-curable polyurethane composition, - applied onto a first substrate and, during the open time of the composition, contacting the composition with a second substrate; or - onto a first substrate and onto a second substrate and laminating the two substrates together during the open time of the composition; or - application between two substrates, (ii) subsequently curing the composition by contact with moisture.

[0145] For this method, it is preferred that the composition have a paste-like consistency and a volatile organic solvent content of less than 5% by weight.

[0146] The elastomeric coating or sealant may further be used by a method of making an elastomeric coating and / or sealant, comprising the steps of: (i) applying a moisture-curable polyurethane composition onto a substrate; (ii) curing the composition by contact with moisture.

[0147] For this method, it is preferred that the composition have a liquid, low viscosity consistency.

[0148] In a preferred embodiment, the elastic coating is part of a floor system, in particular an outdoor floor system, preferably a balcony, terrace, footbridge or staircase.

[0149] In another preferred embodiment, the resilient coating is part of a resilient waterproofing system.

[0150] The elastomeric coating preferably comprises a combination of at least one oligomeric polyisocyanate and an isocyanate-functional polymer having an NCO-functionality not exceeding two.

[0151] Another subject of the invention is a waterproofing system and / or floor system, comprising: - optionally a primer, - optionally a primer layer, and - one or more layers of the moisture-cured polyurethane composition of the present invention, optionally combined with a fiber-reinforced mesh or sprinkled with decorative flakes or silica sand.

[0152] The moisture-curing polyurethane composition of the present invention is therefore preferably applied by pouring it onto the substrate (optionally coated with a primer and / or undercoat layer) and then spreading it evenly, in particular with a squeegee, toothed trowel, spatula, roller or brush, to the desired layer thickness, typically a dry film thickness in the range of 0.05 to 3 mm, in particular a dry film thickness in the range of 0.1 to 1.5 mm.

[0153] In the case of waterproofing systems, a fiber-reinforced mesh is preferably used in combination with the moisture-cure polyurethane composition of the present invention. The fiber-reinforced mesh is preferably submerged in a first layer of the moisture-cure polyurethane composition of the present invention while the composition remains liquid by completely incorporating the mesh into the liquid layer, preferably with a roller or brush. After the composition incorporating the fiber-reinforced mesh has cured, a subsequent layer of the moisture-cure polyurethane composition of the present invention is preferably applied, optionally followed by a topcoat.

[0154] Preferably, the fiber reinforced mesh is a non-woven fiberglass mesh.

[0155] The fiber-reinforced mesh acts as a reinforcement for the waterproofing system, improving its strength and durability. The randomly oriented fibers within the nonwoven fiber mesh provide omnidirectional strength to the coating, while allowing the latter to remain highly elastic, improving strength, tear resistance, and puncture resistance. The nonwoven glass fiber mesh is particularly easy to handle and can easily conform to any surface shape. It is important that the liquid composition completely wets and penetrates the mesh, completely incorporating it into the coating.

[0156] In the case of floor systems, the moisture-curing polyurethane composition of the present invention can be used in combination with decorative flakes or silica sand. The decorative flakes or silica sand are preferably sprinkled into a still-liquid base coat, which is then overcoated with the moisture-curing polyurethane composition of the present invention as a top coat. Such top coats are preferably free of fillers and pigments and have a clear, transparent appearance.

[0157] The described uses result in an article bonded, sealed and / or coated with the composition of the invention, which article is preferably a building or infrastructure or part thereof, preferably a bridge, roof, balcony, terrace, staircase or facade, or it is an industrial or consumer product or part thereof, in particular a window, pipe, household machine, car, bus, truck, rail vehicle, ship, aircraft or helicopter.

[0158] The moisture-cured polyurethane composition described herein has numerous advantages. It is easy to apply and cures rapidly to form a strong, preferably elastic, material. The cured material has excellent mechanical properties, particularly high tensile strength and high elongation at break, combined with a relatively high modulus. It allows for compositions with a very low content of diisocyanate monomers, which is safe for users and the environment, and which are very stable to UV and water attack. The use of a mixture of aldimine isomers according to the present invention makes it possible to surpass the properties of reference compositions containing other aldimines. [Example]

[0159] The following examples illustrate the present invention without, however, limiting it.

[0160] "Normal climate" means a temperature of 23±1°C and a relative humidity of 50±5%, abbreviated as "NC".

[0161] Unless otherwise stated, chemicals were purchased from Sigma-Aldrich Chemie GmbH and used as received.

[0162] Amines used: Vestamine® PACM: 4,4'-methylene-bis(cyclohexylamine), a mixture of isomers containing approximately 20% trans,trans-isomer, liquid at room temperature, solidifies at approximately 15°C (manufactured by Evonik) Dicykan®: 4,4'-methylene-bis(cyclohexylamine), a mixture of isomers containing approximately 50% trans,trans-isomer, solid at room temperature, solidifies at approximately 38°C (manufactured by BASF) IPDA: 3-aminomethyl-3,5,5-trimethylcyclohexylamine (Vestamin® IPD, manufactured by Evonik) Jeffamine® T-403: Polyoxypropylene triamine with an average molecular weight of about 440 g / mol (manufactured by Huntsman).

[0163] Preparation of aldimines: The amine content (total content of free amino and aldimino groups) of the prepared aldimines was determined by titration (using 0.1 N HClO4 in acetic acid, crystal violet indicator) and is expressed in mmol N / g.

[0164] The viscosity was measured using a Rheotec RC30 cone-plate viscometer with an automatic temperature control mechanism (cone diameter: 50 mm, cone angle: 1°, cone-plate distance: 0.05 mm, shear rate: 10 s -1 ) was used for measurement.

[0165] Aldimine A1: a mixture of isomers of N,N'-bis(2,2-dimethyl-3-(N-morpholino)propylidene)-4,4'-methylene-bis(cyclohexylamine) with a ratio of trans,trans-isomer to the sum of cis,trans-isomer and cis,cis-isomer of about 20 / 80 210.4 g (1 mol) of Vestamine® PACM was placed in a round-bottom flask under a nitrogen atmosphere. Then, with good stirring, 359.5 g (2.1 mol) of 2,2-dimethyl-3-(N-morpholino)propanal was added, followed by removal of volatile components at 80°C under a vacuum of 10 mbar. The product thus obtained was a clear, yellow liquid with a viscosity of 13.9 Pa·s at 20°C and an amine content of 7.68 mmol N / g (which corresponds to a calculated aldimine equivalent of approximately 267 g / Eq).

[0166] Aldimine A2: a mixture of isomers of N,N'-bis(isobutylidene)-4,4'-methylene-bis(cyclohexylamine) with a ratio of trans,trans-isomer to the sum of cis,trans-isomer and cis,cis-isomer of about 20 / 80 42.1 g (0.20 mol) of Vestamine® PACM was placed in a round-bottom flask under a nitrogen atmosphere. 30.3 g (0.42 mol) of isobutyraldehyde was then slowly added using a dropping funnel with water bath cooling and good stirring, followed by removal of volatile components at 80°C under a vacuum of 10 mbar. The product thus obtained was a clear, colorless liquid with a viscosity of 138 mPa·s at 20°C (83 mPa·s at 25°C) and an amine content of 6.13 mmol N / g (which corresponds to a calculated aldimine equivalent of approximately 163 g / Eq).

[0167] Aldimine A3: a mixture of isomers of N,N'-bis(2,2-dimethyl-3-acetoxypropylidene)-4,4'-methylene-bis(cyclohexylamine) with a ratio of trans,trans-isomer to the sum of cis,trans-isomer and cis,cis-isomer of about 20 / 80 42.1 g (0.20 mol) of Vestamine® PACM was placed in a round-bottom flask under a nitrogen atmosphere. 60.6 g (0.42 mol) of 2,2-dimethyl-3-acetoxypropanal was then added with good stirring, followed by removal of volatile components at 80°C under a vacuum of 10 mbar. The product thus obtained was a clear, yellow liquid with a viscosity of 1.9 Pa·s at 20°C and an amine content of 4.19 mmol N / g (which corresponds to a calculated aldimine equivalent of approximately 239 g / Eq).

[0168] Aldimine A4: a mixture of isomers of N,N'-bis(2,2-dimethyl-3-lauroyloxypropylidene)-4,4'-methylene-bis(cyclohexylamine) with a ratio of trans,trans-isomer to the sum of cis,trans-isomer and cis,cis-isomer of about 20 / 80 42.1 g (0.20 mol) of Vestamine® PACM was placed in a round-bottom flask under a nitrogen atmosphere. 119.5 g (0.42 mol) of 2,2-dimethyl-3-lauroyloxypropanal was then added with good stirring, followed by removal of volatile components at 80°C under a vacuum of 10 mbar. The product thus obtained was a clear, yellow liquid with a viscosity of 468 mPa·s at 20°C and an amine content of 2.59 mmol N / g (which corresponds to a calculated aldimine equivalent of approximately 386 g / Eq).

[0169] Aldimine B1: a mixture of isomers of N,N'-bis(2,2-dimethyl-3-(N-morpholino)propylidene)-4,4'-methylene-bis(cyclohexylamine) having a ratio of trans,trans-isomer to the sum of cis,trans-isomer and cis,cis-isomer of about 50 / 50 210.4 g (1 mol) Dicykan® was melted at 60°C and placed in a round-bottom flask under a nitrogen atmosphere. Then, with good stirring, 359.5 g (2.1 mol) of 2,2-dimethyl-3-(N-morpholino)propanal was added, followed by removal of volatile components at 80°C under a vacuum of 10 mbar. The product thus obtained was a brown liquid with a viscosity of 13.9 Pa·s at 20°C, but solidified upon storage at room temperature and had an amine content of 7.68 mmol N / g (which corresponds to a calculated aldimine equivalent of approximately 267 g / Eq).

[0170] Aldimine B2: a mixture of isomers of N,N'-bis(isobutylidene)-4,4'-methylene-bis(cyclohexylamine) having an approximately 50 / 50 ratio of trans,trans-isomer to the sum of cis,trans-isomer and cis,cis-isomer 42.1 g (0.20 mol) Dicykan® was melted at 60°C and placed in a round-bottom flask under a nitrogen atmosphere. 30.3 g (0.42 mol) of isobutyraldehyde was then added via a dropping funnel with water bath cooling and good stirring, followed by removal of volatile components at 80°C under a vacuum of 10 mbar. The product thus obtained was a clear, brown liquid with a viscosity of 150 mPa·s at 20°C (100 mPa·s at 25°C), which gradually solidified upon storage at room temperature and had an amine content of mmol N / g (which corresponds to a calculated aldimine equivalent of approximately 163 g / Eq).

[0171] Aldimine B3: a mixture of isomers of N,N'-bis(2,2-dimethyl-3-acetoxypropylidene)-4,4'-methylene-bis(cyclohexylamine) having an approximately 50 / 50 ratio of trans,trans-isomer to the sum of cis,trans-isomer and cis,cis-isomer 42.1 g (0.20 mol) Dicykan® was melted at 60°C and placed in a round-bottom flask under a nitrogen atmosphere. 60.6 g (0.42 mol) of 2,2-dimethyl-3-acetoxypropanal was then added with good stirring, followed by removal of volatile components at 80°C under a vacuum of 10 mbar. The product thus obtained was a clear, brown liquid with a viscosity of 2.7 Pa·s at 20°C and an amine content of 4.26 mmol N / g (which corresponds to a calculated aldimine equivalent of approximately 235 g / Eq).

[0172] Aldimine B4: a mixture of isomers of N,N'-bis(2,2-dimethyl-3-lauroyloxypropylidene)-4,4'-methylene-bis(cyclohexylamine) having an approximately 50 / 50 ratio of trans,trans-isomer to the sum of cis,trans-isomer and cis,cis-isomer 42.1 g (0.20 mol) Dicykan® was melted at 60° C. and placed in a round-bottom flask under a nitrogen atmosphere. 119.5 g (0.42 mol) of 2,2-dimethyl-3-lauroyloxypropanal was then added with good stirring, followed by removal of volatile components at 80° C. under a vacuum of 10 mbar. The product thus obtained was a clear, brown liquid with a viscosity of 518 mPa·s at 20° C. and an amine content of 2.59 mmol N / g (which corresponds to a calculated aldimine equivalent of approximately 386 g / Eq).

[0173] Aldimine B5: a mixture of isomers of N,N'-bis(benzylidene)-4,4'-methylene-bis(cyclohexylamine) with a ratio of trans,trans-isomer to the sum of cis,trans-isomer and cis,cis-isomer of about 20 / 80 42.1 g (0.20 mol) of Vestamine® PACM was placed in a round-bottom flask under a nitrogen atmosphere. 44.6 g (0.42 mol) of benzaldehyde was then added with good stirring, followed by removal of volatile components at 80° C. under a vacuum of 10 mbar. The product thus obtained was a yellow solid with an amine content of 5.02 mmol N / g (calculated to an aldimine equivalent of approximately 199 g / Eq). The solid product had a melting point above 80° C.

[0174] Aldimine B6: a mixture of isomers of N,N'-bis(benzylidene)-4,4'-methylene-bis(cyclohexylamine) having an approximately 50 / 50 ratio of trans,trans-isomer to the sum of cis,trans-isomer and cis,cis-isomer 42.1 g (0.20 mol) Dicykan® was melted at 60° C. and placed in a round-bottom flask under a nitrogen atmosphere. 44.6 g (0.42 mol) of benzaldehyde was then added with good stirring, followed by removal of volatile components at 80° C. under a vacuum of 10 mbar. The product thus obtained was a yellow solid with an amine content of 5.03 mmol N / g (calculated to an aldimine equivalent of approximately 199 g / Eq). The solid product had a melting point above 100° C.

[0175] Aldimine D1: N,N'-bis(2,2-dimethyl-3-(N-morpholino)propylidene)-3-aminomethyl-3,5,5-trimethylcyclohexylamine 170.3 g (1 mol) of IPDA was placed in a round-bottom flask under a nitrogen atmosphere. Then, with good stirring, 359.5 g (2.1 mol) of 2,2-dimethyl-3-(N-morpholino)propanal was added, followed by removal of volatile components at 80°C under a vacuum of 10 mbar. The product thus obtained was an almost colorless liquid with an amine content of 8.25 mmol N / g (which corresponds to a calculated aldimine equivalent of approximately 247 g / Eq).

[0176] Aldimine D2: N,N',N"-tris(2,2-dimethyl-3-(N-morpholino)propylidene)polyoxypropylenetriamine 157.1 g (1 mol N) of Jeffamine® T-403 was placed in a round-bottom flask under a nitrogen atmosphere. Then, with good stirring, 179.8 g (1.05 mol) of 2,2-dimethyl-3-(N-morpholino)propanal was added, followed by removal of volatile components at 80° C. under a vacuum of 10 mbar. The product thus obtained was an almost colorless liquid with an amine content of 6.44 mmol N / g (which corresponds to a calculated aldimine equivalent of approximately 320 g / Eq).

[0177] Aldimines A1 to A4 are mixtures of isomeric aldimines according to the invention. Aldimines B1 to B6 as well as D1 and D2 are reference substances.

[0178] [Table 1]

[0179] Preparation of isocyanate-functional polyurethane polymers: The content of diisocyanate monomers was measured after derivatization with N-propyl-4-nitrobenzylamine using HPLC (detection: photodiode array, mobile phase: 0.04 M sodium acetate / acetonitrile).

[0180] The viscosity was measured using a Rheotec RC30 cone-plate viscometer with an automatic temperature control mechanism (cone diameter: 25 mm, cone angle: 1°, cone-plate distance: 0.05 mm, shear rate: 10 s -1 ) was used for measurement.

[0181] Polymer P1: 590 g of polyoxypropylene diol (Acclaim® 4200, OH value 28.5 mg KOH / g, manufactured by Covestro), 1180 g of ethylene oxide-capped polyoxypropylene triol (Caradol® MD34-02, OH value 35.0 mg KOH / g, manufactured by Shell), and 230 g of isophorone diisocyanate (Vestanat® IPDI, manufactured by Evonik) were reacted according to known procedures at 80° C. The polymer thus obtained had an NCO content of 2.1% by weight, a viscosity (20° C.) of 22.5 Pa·s, and a content of isophorone diisocyanate monomer of about 2% by weight.

[0182] Polymer P2: 780 g of ethylene oxide-capped polyoxypropylene triol (Desmophen® 5031 BT, OH value 28.0 mg KOH / g, manufactured by Covestro) and 220 g of isophorone diisocyanate (Vestanat® IPDI, manufactured by Evonik) were reacted at 80°C according to known procedures to form a mixture having an NCO content of 6.4 wt.% and an isophorone diisocyanate monomer content of about 12 wt.%. The volatile components (especially mostly isophorone diisocyanate monomer) were then removed from the mixture by distillation in a short-path evaporator (jacket temperature 160°C, 0.1-0.005 mbar). The polymer thus obtained had an NCO content of 1.9 wt.%, a viscosity of 10 Pa·s (at 20°C), and an isophorone diisocyanate monomer content of about 0.02 wt.%.

[0183] Polymer P3: 818 g of polyoxypropylene diol (Acclaim® 4200, OH value 28.5 mg KOH / g, manufactured by Covestro) and 182 g of isophorone diisocyanate (Vestanat® IPDI, manufactured by Evonik) were reacted at 80°C according to known procedures to form a mixture with an NCO content of 5.1% by weight and a content of approximately 9% by weight of isophorone diisocyanate monomer. The volatile components (in particular, mostly isophorone diisocyanate monomer) were then removed from the mixture by distillation in a short-path evaporator (jacket temperature 160°C, 0.1-0.005 mbar). The polymer thus obtained had an NCO content of 1.9% by weight, a viscosity of 6.5 Pa·s (at 20°C), and a content of approximately 0.03% by weight of isophorone diisocyanate monomer.

[0184] Polymer P4: 600 g of polyoxypropylene diol (Voranol® 1010L, OH value 112 mg KOH / g, Dow) and 400 g of isophorone diisocyanate (Vestanat® IPDI, Evonik) were reacted at 80°C according to known procedures to form a mixture with an NCO content of 10% by weight and an isophorone diisocyanate monomer content of about 13% by weight. The volatile components (especially mostly isophorone diisocyanate monomer) were then removed from the mixture by distillation in a short-path evaporator (jacket temperature 160°C, 0.1-0.005 mbar). The polymer thus obtained had an NCO content of 5.5% by weight, a viscosity of 21.8 Pa·s (at 20°C), and an isophorone diisocyanate monomer content of about 0.03% by weight.

[0185] Moisture-curable polyurethane composition: Compositions C1~C10: Each composition was prepared by mixing the components shown in Table 2 in the prescribed amounts (parts by weight) in a centrifugal mixer (SpeedMixer™ DAC150, manufactured by FlackTek Inc.) under moisture exclusion conditions, and stored in a moisture-tight container. Solid aldimines were melted at 60°C before use.

[0186] The compositions were tested as follows.

[0187] The viscosity was measured after 1 day of storage in a moisture-tight container under standard climatic conditions ("1 day NC") and again after 7 days of storage in a moisture-tight container in an oven at 60°C ("7 days 60°C") using a thermostatically controlled cone-plate viscometer, Rheotec RC30 (cone diameter: 25 mm, cone angle: 1°, cone-plate distance: 0.05 mm, shear rate: 10 s -1 ) at 20° C. A small increase is an indication of good storage stability.

[0188] The skinning time (skin formation time) was measured under standard climatic conditions by applying a few grams of the composition to a paperboard in a layer approximately 2 mm thick, and then gently touching the surface with an LDPE pipette at intervals until no polymer residue adhered to the pipette when so touched.

[0189] The Shore A hardness was determined in accordance with DIN 53505 using cylindrical specimens 20 mm in diameter and 5 mm thick stored under standard climatic conditions for 7 days.

[0190] To measure the mechanical properties, the compositions were cast onto PTFE-coated foils in layers approximately 2 mm thick and stored under standard climatic conditions for 7 days. Dumbbell-shaped test specimens with a total length of 75 mm, a central (bridge) length of 30 mm, and a central width of 4 mm were then punched out of the cured films. The tensile strength, elongation (at break), and E-modulus 5% (from 0.5 to 5% elongation) were determined using the test specimens in accordance with DIN EN 53504 at a crosshead speed of 200 mm / min.

[0191] The cured films of all compositions were homogeneous and bubble-free.

[0192] The test results are shown in Table 2.

[0193] Reference examples are marked with "(Ref.)".

[0194] [Table 2-1]

[0195] [Table 2-2]

[0196] Moisture-cure polyurethane adhesive: Compositions C11-C14: Each composition was prepared by mixing the components shown in Table 3 in the amounts (parts by weight) indicated in Table 3 in a planetary mixer under vacuum and in the absence of moisture, and then stored in a moisture-tight container. Solid aldimine B1 was melted before addition.

[0197] A thickening paste was prepared by placing 300 g of diisodecyl phthalate and 48 g of 4,4'-diphenylmethane diisocyanate (Desmodur® 44 MC L, manufactured by Covestro) in a vacuum mixer, heating the mixture to 40°C, and then adding 27 g of monobutylamine dropwise under vigorous stirring. The paste thus obtained was further stirred under vacuum and allowed to cool for 1 hour.

[0198] The compositions were tested as follows.

[0199] The skinning time (time to skin formation) and Shore A hardness were measured as described for composition C1.

[0200] To measure the mechanical properties, each composition was pressed between two pieces of wax-coated transfer paper to form a 2 mm thick film, which was then stored under standard climatic conditions. After removing the wax-coated paper, dumbbell-shaped specimens were punched out of the cured film and tested for tensile strength, elongation, and E-modulus 5% as described for composition C1.

[0201] The cured films of all adhesives were homogeneous and bubble-free.

[0202] The test results are shown in Table 3.

[0203] Reference examples are marked with "(Ref.)".

[0204] [Table 3]

[0205] Moisture-cure polyurethane coating: Compositions C15-C17: Each composition was prepared by mixing the components shown in Table 4 in the prescribed amounts (parts by weight) in a centrifugal mixer under moisture exclusion and stored in a moisture-tight container. Prior to use, solid aldimine B1 was melted at 60°C, while salicylic acid was dissolved in 1-methoxy-2-propyl acetate.

[0206] The compositions were tested as follows.

[0207] The viscosity was measured at 20°C using a Rotothinner type viscometer (with spherical spindle DV2011, 500 rpm) once after storage in a moisture-tight container at standard climatic conditions for 1 day ("1 day NC") and again after storage in a moisture-tight container in an oven at 40°C for 21 days ("21 days 40°C").

[0208] Cure speed ("BK Dry Time") was measured at 20°C / 45% relative humidity using a Beck-Koller Dry Time Recorder according to ASTM D5895.

[0209] Two-layer cured films were prepared for each coating to measure mechanical properties. To prepare the films, an 800 μm thick first layer was applied using a drawdown bar and cured for 24 hours at standard climatic conditions (NC). A 400 μm thick second layer was then applied at a 90° angle and cured again for 24 hours at NC. The two-layer films were then placed in a 60°C oven for 72 hours. After a further 24 hours at NC, 100 mm long, 25 mm wide plate specimens were punched from the films, and their tensile strength, elongation at break, and Young's modulus were measured according to BS EN ISO 527-3 at a crosshead speed of 180 mm / min.

[0210] The cured films of all coatings were homogeneous and bubble-free.

[0211] The results are shown in Table 4.

[0212] Reference examples are marked with "(Ref.)".

[0213] [Table 4] The present disclosure includes the following inventive aspects: <Aspect 1> A mixture of isomers of aldimines of formula (Ia), (Ib) and (Ic) [ka] wherein each Y is independently a monovalent, linear or branched C alkyl group which may contain ether, ester, tertiary amine, amide, urethane and / or urea groups. 3 ~C 20 an alkyl, cycloalkyl or arylalkyl group of the formula: a ratio of the trans,trans-isomer (Ia) to the sum of the cis,trans-isomer (Ib) and the cis,cis-isomer (Ic) being within the range of (5 / 95) to (30 / 70); A mixture of isomeric aldimines. <Aspect 2> A mixture of aldimine isomers according to aspect 1, wherein the ratio of the trans,trans-isomer (Ia) to the sum of the cis,trans-isomer (Ib) and the cis,cis-isomer (Ic) is within the range of (15 / 85) to (25 / 75). <Aspect 3> Y is a branched C 3 ~C 7 A mixture of isomers of aldimines according to aspect 1 or 2, which is alkyl, more preferably isopropyl or hept-3-yl, especially isopropyl. <Aspect 4> A mixture of isomers of aldimines according to embodiment 1 or 2, wherein Y is a group of formula (II):

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Claims

1. A mixture of isomers of aldimines of formula (Ia), (Ib) and (Ic) 【Chemistry 1】 wherein each Y is independently a monovalent, linear or branched C alkyl group which may contain ether, ester, tertiary amine, amide, urethane and / or urea groups. ３ ~C ２０ wherein the alkyl, cycloalkyl or arylalkyl group is the ratio of the trans,trans-isomer (Ia) to the sum of the cis,trans-isomer (Ib) and the cis,cis-isomer (Ic) is in the range of (5 / 95) to (30 / 70); A mixture of isomeric aldimines.

2. 2. The mixture of aldimine isomers according to claim 1, wherein the ratio of the trans,trans-isomer (Ia) to the sum of the cis,trans-isomer (Ib) and the cis,cis-isomer (Ic) is within the range of (15 / 85) to (25 / 75).

3. Y is a branched C ３ ~C ７ A mixture of isomers of aldimines according to claim 1 or 2, wherein the aldimine is alkyl, more preferably isopropyl or hept-3-yl, especially isopropyl.

4. 3. A mixture of aldimine isomers according to claim 1 or 2, wherein Y is a group of formula (II): 【Chemistry 2】 (In the formula, R １ and R ２ are the same or different, and C １ ~C ４ alkyl or together C ４ ~C ６ forming an alkylene, and R ５ is H or C which may contain one or more ether groups １ ~C １７ alkyl).

5. 3. A mixture of aldimine isomers according to claim 1 or 2, wherein Y is a group of formula (III): 【Transformation 3】 (In the formula, R １ and R ２ are the same or different, and C １ ~C ４ alkyl or together C ４ ~C ６ forming an alkylene, and R ３ and R ４ are the same or different and may contain ether oxygen; １ ~C ８ C which may be alkyl or, together with an ether oxygen, ４ ~C ６ forming an alkylene).

6. R １ and R ２ are both methyl, and R ３ and R ４ 6. The mixture of aldimine isomers according to claim 5, wherein:

7. Use of a mixture of aldimine isomers according to any one of claims 1 to 6 as a latent curing agent for moisture-cured polyurethane compositions.

8. 8. The use according to claim 7, wherein the mixture of aldimine isomers is used in combination with at least one further aldimine of formula (VII): 【Chemistry 4】 (In the formula, n is 2 or 3; A is the residue of a diamine or triamine after removal of the amine group, wherein the diamine or triamine is selected from the group consisting of hexane-1,6-diamine, 2-methylpentane-1,5-diamine, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, 4(2)-methylcyclohexane-1,3-diamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)benzene, 1,2-diaminocyclohexane, an average molecular weight M in the range of 200 to 4,000 g / mol, ｎ and an average molecular weight M in the range of 380 to 5,000 g / mol. ｎ and Y is the same substituent in formulae (Ia), (Ib), and (Ic) and in formula (VII).

9. A moisture-cure polyurethane composition comprising: - an isocyanate-functional polymer obtained by reacting at least one polyisocyanate and / or at least one diisocyanate monomer with at least one polyol, and A mixture of isomers of aldimines according to any one of claims 1 to 6.

10. 10. The composition of claim 9, comprising an isocyanate-functional polymer having an NCO-content in the range of 1 to 10% by weight derived from at least one polyether polyol.

11. 11. The composition of claim 9 or 10, comprising less than 0.1% by weight of the diisocyanate monomer, based on the total composition.

12. A cured composition obtained after contacting the composition according to any one of claims 9 to 11 with moisture.

13. 13. An elastic coating, adhesive, or sealant comprising the cured composition of claim 12.

14. A primer, paint, or varnish comprising the cured composition of claim 12.

15. Waterproofing or flooring systems, including: - optionally a primer undercoat layer, - optionally a primer layer, and - one or more layers of the composition according to any one of claims 10 to 12, optionally combined with a fiber reinforced mesh or sprinkled with decorative flakes or silica sand.

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