Curable composition having an aldehyde-functional polymer

Abstract

The invention relates to a curable composition comprising: - a first component containing at least one aldehyde-group-containing polymer having a hydrocarbon, polyether or polyester backbone; and - a second component containing at least one compound having two or more thiol groups. The composition cures in ambient conditions, irrespective of humidity, rapidly and without problems to form a resilient polymer having high strength and ductility, good adhesion properties and good stability with respect to heat and water. The composition is particularly suitable for use as a resilient adhesive, sealant or coating having a high level of robustness during production, storage, processing and use.

Description

[0001] CURABLE COMPOSITION WITH ALDEHYDE FUNCTIONAL

[0002] POLYMER

[0003] Technical area

[0004] The invention relates to reactive polymer compositions and their use as room temperature curable elastic adhesives, sealants or coatings.

[0005] State of the art

[0006] Reactive polymer compositions that cure at room temperature and can be used as adhesives, sealants, or coatings with elastic properties are well known. Polyurethane systems, which cure through the reaction of isocyanate groups with polyols and / or moisture, forming particularly highly elastic polymers, are widely used. The formulation, manufacture, and use of polyurethane systems pose a number of challenges in practice. These systems usually contain significant amounts of monomeric diisocyanates, which can irritate the eyes, skin, and mucous membranes. The moisture sensitivity of the isocyanate groups can lead to premature crosslinking reactions associated with increased viscosity and even gelling, thus impairing shelf life and storage stability.In one-component systems, the water required for curing must penetrate from the outside in the form of atmospheric moisture, making application in thick layers or between moisture-proof substrates difficult. Two-component systems with a polyol and an isocyanate component pose the problem that the isocyanate groups can react not only with the hydroxyl groups of the polyols but also with any water present, which can lead to blistering and incompletely crosslinked polymers.

[0007] Reactive polymer compositions based on silane-functional polymers or silicones are also widely used. These polymer systems cure through hydrolysis and condensation of silane groups, releasing alcohols, especially methanol or ethanol, or oximes, which are toxic and cause emissions. Furthermore, they usually contain high amounts of low-molecular-weight silanes, which are also harmful to health. Due to the moisture sensitivity of the silane groups, these polymer systems are also challenging to manufacture and use and do not always produce the desired results.

[0008] Polym.Chem., 2019, 10, 279, describes the crosslinking of mercapto-containing silicones with aldehydes such as benzaldehyde or terephthaldehyde. Such polysiloxane-chain-containing polymer systems are not paintable and have poor compatibility with many ingredients and substrates. They are therefore only suitable for special applications.

[0009] US 3,392,148 describes room temperature solid polyurethanes with aldehyde end groups and their curing by heating in the presence of an acid catalyst.

[0010] US 2023 / 044535 describes polyimines from the reaction of poly(urethane)aldehydes and polyetheramines and their use in moisture-curing polyurethane compositions.

[0011] Description of the invention

[0012] The object of the present invention is to provide a novel, room temperature curable polymer composition which is suitable as an elastic adhesive, sealant or coating and overcomes the disadvantages of the known polymer systems.

[0013] This object is achieved with a curable composition as described in claim 1. The composition comprises a first component containing at least one aldehyde-containing polymer with a hydrocarbon, polyether, or polyester backbone and a second component containing at least one compound with two or more thiol groups. The composition according to the invention has several surprising and advantageous properties compared to prior art polymer systems.

[0014] The composition is not sensitive to moisture and allows for a high degree of formulation freedom, as additives commonly used in curable compositions can be used in both components without causing problems with the storage stability of the respective component. Furthermore, the composition is easily processable under ambient conditions, typically requiring hardly any organic solvents for dissolving or diluting, and no water for emulsifying or dispersing components. The composition cures surprisingly quickly and smoothly under ambient conditions, regardless of humidity, without causing any emissions. Furthermore, curing is highly controllable using commercially available acids such as toluenesulfonic acid or dodecylbenzenesulfonic acid, eliminating the need for metal-containing catalysts.Upon curing, a non-sticky, elastic polymer with high strength and extensibility, good tear resistance, and good adhesion properties is formed. Surprisingly, the inventive composition containing a polymer containing aldehyde groups and a thiol as a curing agent exhibits significantly better properties compared to a reverse system with a polymer containing mercapto groups and an aldehyde as a curing agent. This is not apparent from the prior art.

[0015] In a preferred embodiment of the invention, the composition contains at least one filler selected from aluminum oxide, aluminum hydroxide, zinc oxide, and zinc hydroxide, especially aluminum hydroxide. Such a composition exhibits particularly high strength with high extensibility and surprisingly good stability to heat and moisture after curing.

[0016] The curable composition is particularly suitable for use as an elastic adhesive, sealant or coating.

[0017] Further aspects of the invention are the subject of further independent claims. Particularly preferred embodiments of the invention are the subject of the dependent claims.

[0018] Ways to implement the invention

[0019] The invention relates to a curable composition comprising

[0020] - a first component containing at least one aldehyde group-containing polymer with a hydrocarbon, polyether or polyester backbone, and

[0021] - a second component containing at least one compound with two or more thiol groups. The term "molecular weight" refers to the molar mass (in grams per mole) of a molecule. The term "average molecular weight" refers to the number average molecular weight M na polydisperse mixture of oligomeric or polymeric molecules. It is determined by gel permeation chromatography (GPC) using polystyrene as a standard.

[0022] Substance names beginning with “poly” such as polymercaptan, polyaldehyde, polyisocyanate or polyol refer to substances that formally contain two or more of the functional groups mentioned in their name per molecule.

[0023] A composition is described as “storage-stable” if it can be stored at room temperature in a suitable container for a prolonged period, typically for at least 3 months up to 6 months or more, without its application or use properties being changed by storage to an extent relevant to its use.

[0024] A “filler” is a powdery substance that is solid at room temperature and is not soluble in the curable composition.

[0025] “Room temperature” is defined as a temperature of 23 °C.

[0026] All industry standards and norms mentioned in this document refer to the versions valid at the time of filing the initial application. Percentages by weight (wt%) refer to the mass fraction of a component of a composition or molecule relative to the entire composition or molecule, unless otherwise specified. The terms "mass" and "weight" are used synonymously in this document.

[0027] The first and second components of the curable composition are individually stable and are stored in separate containers until they are mixed together shortly before or during application.

[0028] The aldehyde-containing polymer is preferably liquid at room temperature. In particular, it has a viscosity at 20 °C of 0.5 to 1,000 Pa s, preferably 1 to 500 Pa s, in particular 2 to 200 Pa s, measured using a cone-plate viscometer with a cone diameter of 10 mm, a cone angle of 1°, a cone-tip-to-plate distance of 0.05 mm, and a shear rate of 10 s -1 Such polymers are easy to handle at ambient temperatures even without the addition of solvents or thinners.

[0029] The aldehyde group-containing polymer has a hydrocarbon, polyether or polyester backbone.

[0030] Particularly suitable as a hydrocarbon backbone are hydrocarbon chains or hydrocarbon chains substituted with acrylate groups. Hydrocarbon chains, especially polybutadiene chains, are preferred.

[0031] Poly(oxyalkylene) chains are particularly suitable as polyether backbones. Preferred poly(oxyalkylenes) are poly(oxyethylene), poly(oxy-1,2-propylene), poly(oxy-1,3-propylene), poly(oxy-1,4-butylene), poly(oxy-1,2-butylene) or a mixture of these poly(oxyalkylenes). Of these, preference is given to poly(oxy-1,2-propylene), poly(oxy-1,3-propylene) or poly(oxy-1,4-butylene), in particular poly(oxy-1,2-propylene), where a poly(oxy-1,2-propylene) backbone can contain 0 to 20% by weight of poly(oxyethylene) units, based on the poly(oxyalkylene) backbone, in particular at the chain ends.

[0032] Polyester chains derived from lactones or from di- or tricarboxylic acids and di- or tricarboxylic acids, as well as chains containing triglycerides, are particularly suitable as polyester backbones.

[0033] Preferred di- or tricarboxylic acids are selected from succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, hexahydrophthalic acid, dimer fatty acids and trimer fatty acids.

[0034] Preferred diols or triols are selected from 1,2-ethanediol, diethylene glycol, 1,2-propanediol, dipropylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, trimethylolpropane, glycerin, castor oil, dimer fatty alcohols, and trimer fatty alcohols. Polyester chains containing esters of dimer fatty acids, trimer fatty acids, adipic acid, and / or terephthalic acid, in particular esters of dimer or trimer fatty acids, are particularly preferred.

[0035] Also particularly preferred are polyester chains containing triglycerides, in particular derived from castor oil, derivatives of castor oil or vegetable oils.

[0036] Preferred are aldehyde group-containing polymers with a polyether or polyester backbone.

[0037] Particularly preferred are aldehyde-containing polymers with a polyether backbone. Such polymers are easily accessible, comparatively low-viscosity, and enable high extensibility of the cured composition. Also particularly preferred are aldehyde-containing polymers with a polyester backbone containing esters of di- or trimer fatty acids or triglycerides. Such polymers are particularly sustainable.

[0038] Preferably, the aldehyde group-containing polymer has an average molecular weight M nfrom 500 to 20,000 g / mol, preferably 1,000 to 15,000 g / mol, particularly preferably 2,000 to 10,000 g / mol, in particular 3,000 to 8,000 g / mol. This enables cured compositions with high extensibility, strength, and durability.

[0039] The aldehyde group-containing polymer preferably has an average aldehyde equivalent weight of 250 to 6,000 g / eq, preferably 500 to 5,000 g / eq, particularly preferably 800 to 4,000 g / mol, in particular 1,500 to 3,000 g / eq.

[0040] The aldehyde group-containing polymer preferably has an average aldehyde functionality of 1.6 to 6, preferably 1.7 to 4, particularly preferably 1.8 to 3.

[0041] Preferably, the aldehyde groups of the aldehyde-containing polymer are each bonded to an aromatic or heteroaromatic ring. This enables particularly reliable and rapid curing.

[0042] Preferably, the aldehyde groups are bonded to a furan ring, benzene ring, or naphthalene backbone. A particularly preferred aldehyde-containing polymer is a urethane-containing polymer that is liquid at room temperature and has an average aldehyde functionality of 1.7 to 4, especially 1.8 to 3, and an average molecular weight M n from 1,000 to 20,000 g / mol, preferably 2,000 to 10,000 g / mol, in particular 3,000 to 8,000 g / mol, measured by gel permeation chromatography (GPC) against polystyrene as standard.

[0043] Preferably, the aldehyde-containing polymer is a reaction product of at least one hydroxyaldehyde with at least one isocyanate-containing polymer. The isocyanate-containing polymer has a hydrocarbon, polyether, or polyester backbone. In particular, the isocyanate-containing polymer is derived from a polyol selected from hydrocarbon polyols, polyether polyols, polyester polyols, and polyether-polyester polyols.

[0044] Preferably, the isocyanate group-containing polymer is liquid at room temperature, in particular with a viscosity at 20 °C of 0.2 to 500 Pa s, preferably 0.5 to 300 Pa s, in particular 1 to 150 Pa s, measured using a cone-plate viscometer with a cone diameter of 10 mm, a cone angle of 1 °, a cone tip-plate distance of 0.05 mm and a shear rate of 10 s -1 .

[0045] The isocyanate group-containing polymer preferably has an NCO content of 0.5 to 8.4% by weight, preferably 0.7 to 5.5% by weight, in particular 1 to 3.5% by weight.

[0046] The hydroxyaldehyde and the isocyanate-containing polymer are preferably reacted in an OH / NCO ratio of 1 / 1 to 1.2 / 1 at a temperature of 40 to 140 °C, preferably 60 to 120 °C, optionally in the presence of a suitable catalyst. A preferred hydroxyaldehyde is a hydroxyaldehyde with a molecular weight of 60 to 500 g / mol and at least one aldehyde group bonded to an aromatic carbon atom. The hydroxyl group of the hydroxyaldehyde is preferably bonded to an aliphatic carbon atom.

[0047] Preferably, the hydroxyaldehyde is selected from the group consisting of 5-hydroxymethylfurfural, 2-(2-hydroxyethoxy)benzaldehyde, higher ethoxylated 2-hydroxybenzaldehyde, 3-(2-hydroxyethoxy)benzaldehyde, higher ethoxylated 3-hydroxybenzaldehyde, 4-(2-hydroxyethoxy)benzaldehyde, higher ethoxylated 4-hydroxybenzaldehyde, 4-(2-hydroxyethoxy)-3-methoxybenzaldehyde, higher ethoxylated 4-hydroxy-3-methoxybenzaldehyde, propoxylated 2-hydroxybenzaldehyde, propoxylated 3-hydroxybenzaldehyde, propoxylated 4-hydroxybenzaldehyde, propoxylated 4-hydroxy-3-methoxybenzaldehyde, 4,4'-(2-hydroxypropane-1,3-diyl)-bis(oxy)-bis(benzaldehyde) and 4,4'-(2-hydroxypropane-1 ,3-diyl)-bis(oxy)-bis(3-methoxybenzaldehyde).

[0048] Preferred among these are 5-hydroxymethylfurfural, 2-(2-hydroxyethoxy)benzaldehyde, 3-(2-hydroxyethoxy)benzaldehyde, 4-(2-hydroxyethoxy)benzaldehyde, or 4-(2-hydroxyethoxy)-3-methoxybenzaldehyde, especially 5-hydroxymethylfurfural or 3-(2-hydroxyethoxy)benzaldehyde. These hydroxyaldehydes are accessible by simple processes and enable the production of aldehyde-containing polymers with easily manageable viscosity.

[0049] Particularly suitable as isocyanate group-containing polymers are reaction products of polyols with diisocyanates, in particular in a molar NCO / OH ratio of 1.5 / 1 to 10 / 1, preferably of 3 / 1 to 7 / 1, wherein unreacted monomeric diisocyanates have optionally been removed from the polymer.

[0050] Particularly suitable diisocyanates are 1,6-hexane diisocyanate (HDI), 2,2(4),4-trimethyl-1,6-hexane diisocyanate (TMDI), 1-methyl-2,4(6)-diisocyanatocyclohexane (HeTDI), isophorone diisocyanate (IPDI), 4,4'-diisocyanatodicyclohexylmethane (H12MDI), 4(2),4'-diphenylmethane diisocyanate (MDI), or 2,4(6)-toluene diisocyanate (TDI). HDI, IPDI, TDI, or MDI are preferred. IPDI is particularly preferred.

[0051] Suitable polyols are polyols with a hydrocarbon, polyether or polyester backbone, in particular

[0052] - Polyether polyols, in particular polyoxyalkylene diols or polyoxyalkylene triols, in particular polymerization products of ethylene oxide or 1,2-propylene oxide or 1,2- or 2,3-butylene oxide or oxetane or tetrahydrofuran, or mixtures thereof, which may be polymerized with the aid of a starter molecule having two or more active hydrogen atoms.

[0053] Preferred polyether polyols are polyoxypropylene diols or polyoxypropylene triols, or ethylene oxide-terminated (EO-endcapped) polyoxypropylene diols or triols. The latter are polyoxyethylene-polyoxypropylene mixed polyols, which are obtained in particular by further alkoxylating polyoxypropylene diols or triols with ethylene oxide after completion of the polypropoxylation reaction, thus ultimately exhibiting primary hydroxyl groups.

[0054] Preferred polyether polyols have a degree of unsaturation of less than 0.02 mEq / g, in particular less than 0.01 mEq / g.

[0055] - Polyester polyols from the polycondensation of dicarboxylic acids with di- or trihydric alcohols, in particular dimer fatty acid-based polyester polyols, as are commercially available, for example, from Cargill.

[0056] - Polyhydroxyfunctional fats or oils, in particular natural fats or oils, such as castor oil, derivatives of castor oil or vegetable oil-based polyols, such as those available under the trade name Sovermol® (from BASF).

[0057] - Polyetherpolyesterpolyols.

[0058] - Polyhydrocarbon polyols, such as in particular polybutadiene polyols.

[0059] Polyols that are liquid at room temperature are preferred.

[0060] Preferred are polyols with an OH number of 9 to 115 mg KOH / g, preferably 14 to 60 mg KOH / g, in particular 18 to 40 mg KOH / g. Particular preference is given to polyether polyols, dimer fatty acid-based polyester polyols, or polyhydroxy-functional fats or oils. Most preferred are polyether polyols, in particular polyoxypropylene diols, polyoxypropylene triols, ethylene oxide-terminated polyoxypropylene diols, or ethylene oxide-terminated polyoxypropylene triols.

[0061] The second component of the curable composition contains at least one compound with two or more thiol groups.

[0062] Preferably, the compound having two or more thiol groups has 2 to 10, preferably 2 to 6, in particular 2 to 4, thiol groups.

[0063] Preferably, the compound having two or more thiol groups has a thiol equivalent weight of 65 to 800 g / eq, preferably 65 to 400 g / eq, in particular 80 to 300 g / eq.

[0064] Preferably, the compound having two or more thiol groups has a molecular weight of 130 to 1,600 g / mol, in particular 130 to 1,000 g / mol.

[0065] Preferably, the compound having two or more thiol groups is liquid at room temperature. In particular, it has a viscosity at 20 °C of 0.01 to 50 Pa s, preferably 0.05 to 20 Pa s, particularly preferably 0.05 to 10 Pa s, in particular 0.05 to 5 Pa s, measured using a cone-plate viscometer with a cone diameter of 50 mm, a cone angle of 1 °, a cone tip-to-plate distance of 0.05 mm, and a shear rate of 10 s'. 1 , for viscosities of more than 1 Pa s with a cone diameter of 10 mm. Such compounds are easy to handle at ambient temperatures, even without the addition of solvents or thinners.

[0066] A suitable compound with two or more thiol groups is a polymercaptan such as in particular 1,8-dimercaptooctane, 1,10-dimercaptodecane, 1,5-dimercapto-3-oxapentane, 1,8-dimercapto-3,6-dioxaoctane (DMDO), 1,5-dimercapto-3-thiapentane, 1,9-dimercapto-3,7-dithianonane, 1,2-dimercaptomethyl-4,5-dimethylbenzene, 1,3-dimercaptobenzene, 1,4-dimercaptobenzene, 1,3,5-trimercaptobenzene, 1,5-dimercaptonaphthalene, bis(4-mercaptophenyl)thiamethane, 1,2-ethanediol di(2-mercaptoacetate), 1 ,4-Butanediol-di(2-mercaptoacetate), 1, 1, 1-Trimethylolpropane-tris(2-mercaptoacetate), Pentaerythritol-tetrakis(2-mercaptoacetate), 1,2-Ethanediol-di(3-mercaptopropionate) (GDMP), 1,4-Butanediol-di(3-mercaptopropionate), 1 ,1,1-Tri-methylolpropane tris(3-mercaptopropionate) (TMPMP), pentaerythritol tetrakis(3-mercaptopropionate) (PETMP), 3-mercapto-2-hydroxypropyl ether of propoxylated pentaerythritol, tris(2-(3-mercaptopropionyloxy)ethyl) isocyanurate or mercapto group-containing Polysulfide polymers.

[0067] Preferably, the compound having two or more thiol groups is selected from the group consisting of 1,8-dimercapto-3,6-dioxaoctane, 1,2-ethanediol di(2-mercaptoacetate), 1,4-butanediol di(2-mercaptoacetate), 1,1,1-trimethylolpropane tris(2-mercaptoacetate), pentaerythritol tetrakis(2-mercaptoacetate), 1,2-ethanediol di(3-mercaptopropionate), 1,4-butanediol di(3-mercaptopropionate), 1,1,1-trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), 3-mercapto-2-hydroxypropyl ether of propoxylated pentaerythritol with an average Thiol equivalent weight of 180 to 400 g / eq, tris(2-(3-mercaptopropionyloxy)ethyl)isocyanurate and mercapto group-containing polysulfide polymers with an average thiol equivalent weight of 250 to 800 g / eq.

[0068] Of these, compounds with a thiol equivalent weight of 80 to 300 g / eq are preferred.

[0069] A commercial 3-mercapto-2-hydroxypropyl ether of propoxylated pentaerythritol is, for example, Capcure® 3-800 (from Huntsman).

[0070] Polysulfide polymers containing mercapto groups are commercially available, for example, under the trade name Thiokol® from Toray Fine Chemicals.

[0071] Preferred is a combination of an aldehyde group-containing polymer with an average molecular weight M n of at least 1,000 g / mol, preferably at least 2,000 g / mol, and a polymercaptan with a thiol equivalent weight of 80 to 300 g / eq. Such a curable composition enables high extensibility with high strength. In the curable composition, the ratio of the number of thiol groups to the number of aldehyde groups is in the range of 1.5 to 4, preferably 1.7 to 3, in particular 1.8 to 2.5. This enables rapid and trouble-free curing to an elastic, non-sticky polymer.

[0072] In a preferred aspect of the invention, the curable composition contains at least one filler selected from aluminum oxide, aluminum hydroxide, zinc oxide, and zinc hydroxide. Such compositions exhibit reliable and rapid curing and, after curing, particularly high mechanical strength and ductility, as well as surprisingly good stability to heat and moisture, particularly compared to conventional fillers such as kaolin, quartz flour, or calcium carbonate (chalk).

[0073] Aluminum oxide or aluminum hydroxide, especially aluminum hydroxide, is preferred. Aluminum hydroxide is also called aluminum trihydrate (ATH). It also increases thermal conductivity and acts as a flame retardant, making such a composition suitable for applications with increased thermal conductivity or flame retardancy requirements.

[0074] The curable composition preferably contains, based on the total composition, a content of aluminum oxide, aluminum hydroxide, zinc oxide and / or zinc hydroxide of 10 to 90% by weight, preferably 20 to 80% by weight, in particular 25 to 70% by weight.

[0075] The composition preferably contains as catalyst at least one inorganic or organic acid or a compound hydrolyzable to an acid, in particular an organic carboxylic acid such as acetic acid, benzoic acid, salicylic acid, 2-nitrobenzoic acid or lactic acid, or an organic sulfonic acid such as methanesulfonic acid, p-toluenesulfonic acid or p-dodecylbenzenesulfonic acid, or a sulfonic acid ester, phosphoric acid or a phosphoric acid ester, or phosphoic acid or a phosphonic acid ester. Such a composition cures quickly and smoothly and enables cured compositions with good resistance to heat and moisture. The curable composition may additionally contain other components, in particular

[0076] - adhesion promoters, in particular titanates or organoalkoxysilanes such as mercaptosilanes, epoxysilanes, vinylsilanes, (meth)acrylsilanes, carbamatosilanes, alkylsilanes, S-(alkylcarbonyl)mercaptosilanes or oligomeric forms of these silanes;

[0077] - other fillers, in particular ground or precipitated calcium carbonates, which may be coated with fatty acids, in particular stearates, barytes (heavy spars), quartz flours, quartz sands, dolomites, wollastonites, kaolins, calcined kaolins, layered silicates such as mica or talc, zeolites, magnesium hydroxides, silicas including highly dispersed silicas from pyrolysis processes, industrially produced carbon blacks, graphite, ground fillers from agricultural sources such as olive kernel flour or nutshell flour, metal powders, for example of aluminum, copper, iron, silver or steel, PVC powder or hollow spheres;

[0078] - pigments, in particular titanium dioxide, chromium oxide, iron oxides or organic pigments;

[0079] - Plasticizers, in particular phthalates, in particular diisononyl phthalate (DINP), diisodecyl phthalate (DIDP) or di(2-propylheptyl) phthalate (DPHP), hydrogenated phthalates, in particular diisononyl 1,2-cyclohexanedicarboxylate (DINCH), terephthalates, in particular bis(2-ethylhexyl)terephthalate or diisononyl terephthalate (DINT), hydrogenated terephthalates, in particular bis(2-ethylhexyl)1,4-cyclohexanedicarboxylate or diisononyl 1,4-cyclohexanedicarboxylate, isophthalates, trimellitates, adipates, in particular dioctyl adipate (DOA), azelates, sebacates, benzoates, glycol ethers, glycol esters, plasticizers with polyether structure, in particular polypropylene oxide monols, diols or triols, or polypropylene oxide monols, diols or triols with blocked hydroxyl groups, in particular in the form of acetate groups, as well as organic sulfonates or phosphates, in particular diphenyl cresyl phosphate (DPK), polybutenes, polyisobutenes or plasticizers derived from natural fats or oils,in particular epoxidized soy or linseed oil, in particular phthalates, hydrogenated phthalates, adipates or plasticizers with a polyether structure; - fibers, in particular glass fibers, carbon fibers, metal fibers, ceramic fibers, hemp fibers, cellulose fibers or plastic fibers such as polyamide fibers or polyethylene fibers;,

[0080] - Nanofillers such as graphene or carbon nanotubes;

[0081] - dyes;

[0082] - solvents;

[0083] - Modifiers such as hydrocarbon resins, natural or synthetic waxes or bitumen;

[0084] - Rheology modifiers, in particular urea compounds, layered silicates such as bentonites, derivatives of castor oil, hydrogenated castor oil, polyamides, polyurethanes, fumed silicas or hydrophobically modified polyoxyethylenes;

[0085] - drying agents, in particular molecular sieves, calcium oxide, mono-oxazolidines such as Incozol® 2 (from Incorez) or orthoformic acid esters;

[0086] - non-reactive thermoplastic polymers, such as homo- or copolymers of unsaturated monomers, in particular from the group comprising ethylene, propylene, butylene, isobutylene, isoprene, vinyl acetate and alkyl (meth)acrylates, in particular polyethylenes (PE), polypropylenes (PP), polyisobutylenes, ethylene-vinyl acetate copolymers (EVA) and atactic poly-α-olefins (APAO);

[0087] - flame-retardant substances, in particular the fillers already mentioned, aluminium hydroxide or magnesium hydroxide, organic phosphoric acid esters, ammonium polyphosphates, melamine or derivatives thereof, boron compounds or antimony compounds;

[0088] - Additives, in particular wetting agents, flow control agents, defoamers, deaerators, stabilizers against oxidation, heat, light or UV radiation or biocides; as well as other substances commonly used in curable compositions.

[0089] Such additives can be present as part of the first or second component. Substances reactive with mercapto groups are preferably part of the first component, while substances reactive with aldehyde groups are preferably part of the second component. The composition preferably contains at least one mercaptosilane, such as in particular 3-mercaptopropyltrimethoxysilane or 3-mercaptopropyltriethoxysilane, as an adhesion promoter. The mercaptosilane is preferably part of the second component. This enables compositions with particularly good adhesion properties.

[0090] The composition preferably contains at least one plasticizer, in particular selected from DINP, DIDP, DPHP, DINCH, bis(2-ethylhexyl)terephthalate, DINT, bis(2-ethylhexyl)-1,4-cyclohexanedicarboxylate, diisononyl-1,4-cyclohexanedicarboxylate, DOA, polypropylene oxide monols, polypropylene oxide diols, polypropylene oxide triols, polypropylene oxide monol acetates, polypropylene oxide diol diacetates, polypropylene oxide triol triacetates and DPK.

[0091] The composition preferably contains, based on the total composition, 5 to 80% by weight, preferably 10 to 60% by weight, in particular 10 to 40% by weight, of plasticizer.

[0092] In a preferred embodiment of the invention, the curable composition contains fillers and plasticizers, in particular based on the total composition 20 to 90% by weight, in particular 30 to 80% by weight, of fillers and 5 to 60% by weight of plasticizer.

[0093] Preferably, the curable composition contains, based on the total composition

[0094] - 5 to 99% by weight, preferably 5 to 90% by weight, in particular 10 to 70% by weight, of the sum of aldehyde group-containing polymers and compounds having two or more thiol groups,

[0095] - 0 to 60% by weight, preferably 10 to 60% by weight, 10 to 40% by weight, plasticizer,

[0096] - 0 to 90% by weight, preferably 20 to 90% by weight, in particular 30 to 80% by weight, fillers,

[0097] - and optionally other substances. In a preferred embodiment, the curable composition contains at least one ground filler from an agricultural source, in particular a lignin-containing granulate such as olive kernel flour. This enables cured compositions with very high mechanical strength and surprisingly good stability to heat and moisture.

[0098] The curable composition preferably contains less than 10% by weight, more preferably less than 5% by weight, and especially less than 1% by weight, of volatile organic solvents with a boiling point at atmospheric pressure of less than 250°C, based on the total composition. Such a composition causes particularly low emissions.

[0099] The curable composition is preferably not water-based. It is preferably largely free of water or contains only a low water content, in particular less than 10% by weight, preferably less than 5% by weight, especially less than 2% by weight, of water based on the total composition. Such a composition cures rapidly regardless of ambient humidity, can be used in thick layers and / or between waterproof substrates, and exhibits hardly any shrinkage during curing.

[0100] The curable composition preferably contains less than 10% by weight, more preferably less than 5% by weight, and most preferably less than 1% by weight, of silicone compounds. Such a composition is easily paintable and exhibits particularly good adhesion properties.

[0101] The consistency of the first and second components of the curable composition is suitably such that the components can be easily mixed together under ambient conditions using simple methods. Liquid or pasty components are particularly suitable for this purpose.

[0102] The first and second components of the curable composition are prepared separately. The components of each component are mixed together to create a macroscopically homogeneous mass. Each component is stored in a separate container. Suitable containers include a drum, container, hobbock, bucket, canister, can, bag, tubular bag, cartridge, or tube. The components are stable in storage.

[0103] To apply the curable composition, the two components and any other components present are mixed together shortly before or during application.

[0104] The mixing ratio is selected such that the ratio of the number of thiol groups to the number of aldehyde groups is within the preferred range. In parts by weight, the mixing ratio between the first and second components is typically in the range of approximately 100:1 to 1:10, preferably 50:1 to 1:5, in particular 10:1 to 1:2.

[0105] If the components are mixed together prior to application, care must be taken to ensure that not too much time elapses between mixing the components and application, as otherwise the onset of reaction and the associated increase in viscosity may lead to problems such as insufficient flow or slow or incomplete adhesion to the substrate. In particular, the open time of the composition during application should not be exceeded.

[0106] The “open time” is the period of time between the mixing of the components and the end of a state of the composition suitable for processing.

[0107] Mixing is preferably carried out at ambient temperature, in particular at a temperature in the range of -5 to 50°C, in particular 0 to 40°C.

[0108] When the two components are mixed, the composition begins to cure through a chemical reaction. The aldehyde groups react with the thiol groups, primarily forming thioacetal groups. As a result of these crosslinking reactions, the composition cures into a non-sticky, elastic polymer.

[0109] Curing preferably takes place at ambient temperature, in particular at a temperature in the range of -5 to 50°C, in particular 0 to 40°C.

[0110] Another object of the invention is the cured composition obtained from the curable composition after mixing the two components.

[0111] Preferably, the cured composition is elastic and has high strength and high extensibility.

[0112] Preferably, the cured composition has a tensile strength, determined according to DIN EN 53504 as described in the examples, of at least 1 MPa, preferably at least 1.5 MPa.

[0113] The cured composition preferably has an elongation at break, determined according to DIN EN 53504 as described in the examples, of at least 50%, preferably at least 100%, in particular at least 150%.

[0114] The cured composition preferably has a Shore A hardness, determined according to DIN 53505 as described in the examples, in the range from 10 to 90, preferably 20 to 85, in particular 30 to 80.

[0115] Furthermore, the cured composition exhibits good heat and water resistance. Preferably, the cured composition exhibits high strength with high elongation even after storage for 7 days at 100°C or at 70°C and 100% relative humidity, and the Shore A hardness remains within the preferred range.

[0116] Furthermore, the cured composition has good adhesion properties on common substrates such as glass, aluminum, concrete or wood.

[0117] The curable composition is suitable for a variety of applications. It can be used, in particular, as an adhesive, sealant, coating, casting resin, or filler. The invention further relates to the use of the curable composition as an elastic adhesive, elastic sealant, or elastic coating, wherein the first and second components, and any additional components present, are mixed together, and the mixed composition is applied in the liquid state to at least one substrate.

[0118] Suitable substrates include:

[0119] - Glass, glass ceramics, concrete, mortar, cement screed, fiber cement, brick, tile, plaster or natural stones such as granite or marble;

[0120] - Repair or levelling compounds based on PCC (polymer-modified cement mortar) or ECO (epoxy resin-modified cement mortar);

[0121] - Metals or alloys such as aluminum, iron, steel, copper, other non-ferrous metals, including surface-treated metals or alloys such as galvanized or chrome-plated metals;

[0122] - asphalt or bitumen;

[0123] - leather, textiles, paper, wood, wood materials bonded with resins, for example phenolic, melamine or epoxy resins, resin-textile composites or other so-called polymer composites;

[0124] - Plastics such as rigid and soft PVC, polycarbonate, polystyrene, polyester, polyamide, PMMA, ABS, SAN, epoxy resins, phenolic resins, PUR, POM, TPO, PE, PP, EPM or EPDM, each untreated or surface-treated, for example by means of plasma, corona or flames;

[0125] - Fiber-reinforced plastics, such as carbon fiber-reinforced plastics (CFRP), glass fiber-reinforced plastics (GRP), natural fiber-reinforced plastics (NFRP) and sheet molding compounds (SMC);

[0126] - insulating foams, in particular made of EPS, XPS, PUR, PIR, rock wool, glass wool, aerogel or foamed glass (foam glass);

[0127] - coated or painted substrates, in particular painted tiles, painted concrete, powder-coated metals or alloys or painted sheets;

[0128] - Coatings, paints, or varnishes. The substrates may be pretreated before application if necessary, in particular by physical and / or chemical cleaning processes or the application of an activator or primer.

[0129] Two similar or two different substrates can be bonded and / or sealed.

[0130] An article is obtained from the use of the curable composition. The article is in particular bonded, sealed, or coated with the composition. This article may be a building or a part thereof, in particular a building or civil engineering structure, a bridge, a roof, a staircase, or a facade, or it may be an industrial or consumer good, in particular a window, a pipe, a rotor blade of a wind turbine, a household appliance, or a means of transport, such as in particular an automobile, a bus, a truck, a rail vehicle, a ship, an aircraft, or a helicopter, or an attachment thereof.

[0131] Examples

[0132] The following are exemplary embodiments intended to further illustrate the described invention. Of course, the invention is not limited to these described exemplary embodiments.

[0133] The “standard climate” (“NK”) is defined as a temperature of 23±1 °C and a relative humidity of 50±5%.

[0134] Unless otherwise stated, the chemicals used were from Sigma-Aldrich Chemie GmbH.

[0135] Description of the measurement methods:

[0136] The viscosity was measured on a thermostatted cone-plate viscometer Rheotec RC30 (cone diameter 50 mm, cone angle 1 °, cone tip-plate distance 0.05 mm, shear rate 10 s' 1 ) were measured. Viscosities of less than 100 mPa-s were measured at a shear rate of 100 s _1 Viscosities of more than 500 Pa s were measured at a shear rate of 2 s -1 measured.

[0137] Infrared spectra (FT-IR) were measured on undiluted films on a Thermo Scientific Nicolet iS5 FT-IR instrument equipped with a horizontal diamond crystal ATR measurement unit. The absorption bands are given in wavenumbers (cm -1) is indicated.

[0138] Production of polymers containing isocyanate groups:

[0139] Polymer P-1 :

[0140] 780 g of ethylene oxide-terminated polyoxypropylenetriol (Desmophen® 5031 BT, OH number 28.0 mg KOH / g, OH functionality approx. 2.3, from Covestro) and 303 g of isophorone diisocyanate (Vestanat® IPDI, from Evonik) were reacted at 80 °C according to a known method to form a reaction mixture with an NCO content of 9.1 wt%. Subsequently, the volatile components, in particular unreacted isophorone diisocyanate, were removed by distillation in a short-path evaporator (jacket temperature 160 °C, pressure 0.1 to 0.005 mbar), whereby a polymer with an NCO content of 1.84 wt.%, a viscosity of 8.2 Pa s at 20 °C and a content of monomeric isophorone diisocyanate of 0.02 wt.% was obtained.

[0141] Polymer P-2:

[0142] 818 g of polyoxypropylene diol (Acclaim® 4200, OH number 28.5 mg KOH / g, from Covestro) and 227 g of isophorone diisocyanate (Vestanat® IPDI, from Evonik) were reacted at 80 °C using a known method to form a reaction mixture with an NCO content of 6.6% by weight. The volatile components, particularly unreacted isophorone diisocyanate, were then removed by distillation in a short-path evaporator (jacket temperature 160 °C, pressure 0.1 to 0.005 mbar), yielding a polymer with an NCO content of 1.91% by weight, a viscosity of 6.5 Pa s at 20 °C, and a monomeric isophorone diisocyanate content of 0.03% by weight.

[0143] Polymer P-3:

[0144] 725 g of ethylene oxide-terminated polyoxypropylenetriol (Desmophen® 5031 BT, OH number 28.0 mg KOH / g, OH functionality approx. 2.3, from Covestro) and 275 g of 4,4'-diphenylmethane diisocyanate (Desmodur® 44 MC L, from Covestro) were reacted at 80 °C according to a known method to form a reaction mixture with an NCO content of 7.6 wt%. Subsequently, the volatile components, in particular unreacted 4,4'-diphenylmethane diisocyanate, were removed by distillation in a short-path evaporator (jacket temperature 180 °C, pressure 0.1 to 0.005 mbar, condensation temperature 47 °C), whereby a polymer with an NCO content of 1.68 wt.%, a viscosity of 19 Pa s at 20 °C and a content of monomeric 4,4'-diphenylmethane diisocyanate of 0.04 wt.% was obtained.

[0145] Polymer P-4:

[0146] 727.0 g of polyoxypropylenediol (Acclaim® 4200, OH number 28 mg KOH / g, from Covestro) and 273.0 g of 4,4'-diphenylmethane diisocyanate (Desmodur® 44 MC L, from Covestro) were reacted at 80 °C according to a known method to form a reaction mixture with an NCO content of 7.6% by weight. Subsequently, the volatile components, in particular unreacted 4,4'-diphenylmethane diisocyanate, were removed by distillation in a short-path evaporator (jacket temperature 180 °C, pressure 0.1 to 0.005 mbar, condensation temperature 47 °C), whereby a polymer with an NCO content of 1.7 wt.%, a viscosity of 15.2 Pa s at 20 °C and a content of monomeric 4,4'-diphenylmethane diisocyanate of 0.08 wt.% was obtained.

[0147] Polymer P-5:

[0148] 600 g of polyoxypropylene diol (Voranol® 1010 L, OH number 112 mg KOH / g, from Dow) and 533.3 g of isophorone diisocyanate (Vestanat® IPDI, from Evonik) were reacted at 80 °C using a known method to form a reaction mixture with an NCO content of 15.6% by weight. The volatile components, particularly unreacted isophorone diisocyanate, were then removed by distillation in a short-path evaporator (jacket temperature 160 °C, pressure 0.1 to 0.005 mbar), yielding a polymer with an NCO content of 5.18% by weight, a viscosity of 21.8 Pa s at 20 °C, and a monomeric isophorone diisocyanate content of 0.03% by weight.

[0149] Production of aldehyde group-containing polymers:

[0150] Polymers A-1 to A-6: The amounts of the isocyanate-containing polymers specified in Table 1 were reacted with the specified amounts of the corresponding hydroxyaldehyde in the presence of 0.02 wt. % dibutyltin dilaurate at 110 °C under exclusion of moisture until no isocyanate groups were detectable by IR spectroscopy. For the polymers with aromatic isocyanate groups P-3 and P-4, the reaction was carried out without dibutyltin dilaurate and at 80 °C.

[0151] The properties of polymers A-1 to A-6 are given in Table 1. The average molecular weight M of polymer A-1 was n by gel permeation chromatography (GPC) against polystyrene (474 ​​to 2,520,000 g / mol) as a standard with tetrahydrofuran as the mobile phase and a refractive index detector. The average molecular weight M n was 6,100 g / mol.

[0152] Table 1: Preparation and properties of polymers A-1 to A-6, amounts in parts by weight.

[0153] 1 4,4'-(2-Hydroxypropane-1,3-diyl)-bis(oxy)-bis(3-methoxybenzaldehyde), prepared from 2 mol vanillin and 1 mol epichlorohydrin

[0154] Compounds with thiol groups used:

[0155] GDMP ethylene glycol di(3-mercaptopropionate), 123.5 g / eq SH

[0156] (Thiocure® GDMP, from Bruno Bock GmbH) TMPMP 1,1,1-Trimethylolpropane-tris(3-mercaptopropionate), 138 g / eq SH (Thiocure® TMPMP, from Bruno Bock GmbH)

[0157] PETMP Pentaerythritol tetrakis (3-mercaptopropionate), 127 g / eq SH (Thiocure® PETMP, from Bruno Bock GmbH)

[0158] DMDO 1,8-Dimercapto-3,6-dioxaoctane, 91 g / eq SH

[0159] Capcure® 3-800 3-mercapto-2-hydroxypropyl ether of propoxylated pentaerythritol, approx. 267 g / eq SH (from Huntsman)

[0160] Thiokol® LP-33 linear polysulfide polymer with mercapto end groups, 574 g / eq SH (from Toray Fine Chemicals)

[0161] Thiokol® LP-2 linear polysulfide polymer with mercapto end groups, 1886 g / eq SH (from Toray Fine Chemicals)

[0162] Polymer SH-1 Mercapto group-containing polymer from the reaction of Polymer P-1 and 2-thioethanol, approx. 2307 g / eq SH, prepared as described below

[0163] Mercaptosilane 3-Mercaptopropyltrimethoxysilane

[0164] Polymer SH-1 :

[0165] 250.0 g of polymer P-1 with an NCO content of 1.84 wt.%, prepared as described above, were reacted with 8.8 g of 2-mercaptoethanol in the presence of 1.0 g of dibutyltin dilaurate at 80 °C under exclusion of moisture until no isocyanate groups were detectable by IR spectroscopy. The resulting polymer had a theoretical mercapto equivalent weight of 2307 g / eq. Preparation of curable compositions:

[0166] Examples Z-1 to Z-21

[0167] For each example, the ingredients of the first component (K1) listed in Tables 2 to 6 were mixed in the specified amounts (in parts by weight) using a centrifugal mixer (SpeedMixer™ DAC 150, FlackTek Inc.) and stored in a sealed container.

[0168] The ingredients of the second component (K2) listed in Tables 2 to 5 were also processed and stored. Aluminum hydroxide (Martinal® OL-104, from Martinswerk) was used as the "ATH."

[0169] Monarch® 570 (from Cabot) was used as the soot.

[0170] Satintone® W (from BASF) was used as "calcined kaolin".

[0171] A grain size of 0 to 75 pm was used as "quartz flour".

[0172] Omyacarb® 5 GU (from Omya) was used as the “chalk”.

[0173] Dried, ground olive kernel shells from the extraction of olive oil with a particle size of < 100 pm (from Micronizados Vegetales SL) were used as "olive kernel flour".

[0174] The two components of each composition were then processed into a homogeneous liquid using the centrifugal mixer and immediately tested as follows:

[0175] The setting time was determined by moving a freshly mixed amount of approximately 3 g with a spatula at regular intervals in a standard climate until the mass gelled.

[0176] To determine the mechanical properties, the mixed composition was applied to a 2 mm thick film on a silicone-coated release paper. This film was stored for 7 days under standard conditions. Several dumbbell-shaped test specimens with a length of 75 mm, a web length of 30 mm, and a web width of 4 mm were punched out of the film and tested according to DIN EN 53504 at a tensile speed of 200 mm / min for tensile strength, elongation at break, 5% elastic modulus (at 0.5-5% elongation), and 50% elastic modulus (at 0.5-50% elongation). Furthermore, several test specimens were punched out to determine tear propagation resistance and tested according to DIN ISO 34-1, Method B (angular test specimen) at a tensile speed of 500 mm / min. These results are designated "7d NK."

[0177] To determine heat and hydrolysis stability, additional dumbbell-shaped test specimens were stored for 7 days at 70 °C and 100% relative humidity in some examples after 7 days of curing under standard conditions, followed by 24 hours of storage under standard conditions. The tensile strength, elongation at break, 5% elastic modulus, and 50% elastic modulus were determined. These results are marked with the suffix "+7d 70 / 100." Shore A hardness was determined according to DIN 53505 on test specimens cured for 7 days under standard conditions. These results are marked with the suffix "7d NK." To determine heat and hydrolysis stability, additional Shore A test specimens were cured for 7 days under standard conditions, either for an additional 7 days at 70 °C and 100% relative humidity, or for an additional 7 days in a convection oven at 100 °C. After cooling to room temperature, the Shore A hardness was determined as described. These results are indicated with the suffix "+7d 70 / 100" or "+7d 70 / 100" respectively."+7d 100°C".

[0178] As a measure of the strength of an adhesive bond, the tensile shear strength of some compositions on glass was determined. For this purpose, composites were produced by bonding two glass plates degreased with isopropanol and pretreated with Sika® Aktivator-205 (from Sika Switzerland) in such a way that the overlapping adhesive bond had dimensions of 12 x 25 mm and a thickness of 4 mm, and the glass plates protruded at the ends. After storing the composites for 7 days in a standard atmosphere, the tensile shear strength was tested according to DIN EN 1465 at a tensile speed of 20 mm / min. The fracture pattern was then assessed for AF (adhesive failure) or CF (cohesive failure). Without further information, the fracture pattern shown in the table was observed over 90 to 100% of the fracture surface.

[0179] The results are shown in Tables 2 to 6.

[0180] The examples marked "(Ref.)" are comparative examples not according to the invention.

[0181] When the examples according to the invention were cured for 7 days under standard conditions, a non-sticky, elastic material was formed.

[0182] Table 2: Composition and properties of Z-1 to Z-6.

[0183] 1 p-Dodecylbenzenesulfonic acid

[0184] Table 3: Composition and properties of 7.-7 to Z-11.

[0185] 1 p-Dodecylbenzenesulfonic acid

[0186] “nb” stands for “not determined”

[0187]

[0188] Table 4: Composition and properties of Z-1 and Z-12 to Z-15.

[0189] 1 p-Dodecylbenzenesulfonic acid

[0190] “nb” stands for “not determined”

[0191] Table 5: Composition and properties of Z-4 and Z-16 to Z-18.

[0192] 1 p-Dodecylbenzenesulfonic acid

[0193] 2 sticky surface

[0194] Table 6: Composition and properties of Z-19 to Z-21.

[0195] 1 dissolved in heated diisodecyl phthalate

[0196] 2 p-Dodecylbenzenesulfonic acid

[0197] 3 sticky surface

[0198] 4 not measurable (decomposed)

[0199] 5 not measurable (no hardening, crumbly mass)

Claims

Patent claims: 1 . Curable composition comprising - a first component containing at least one aldehyde group-containing polymer with a hydrocarbon, polyether or polyester backbone, and - a second component containing at least one compound having two or more thiol groups.

2. Composition according to claim 1, characterized in that the aldehyde group-containing polymer is liquid at room temperature.

3. Composition according to one of claims 1 or 2, characterized in that the aldehyde group-containing polymer has an average molecular weight M n from 500 to 20,000 g / mol, preferably 1,000 to 15,000 g / mol, particularly preferably 2,000 to 10,000 g / mol, in particular 3,000 to 8,000 g / mol, determined by gel permeation chromatography against polystyrene as standard.

4. Composition according to one of claims 1 to 3, characterized in that the aldehyde group-containing polymer has an average aldehyde functionality of 1 .6 to 6, preferably 1 .7 to 4, particularly preferably 1 .8 to 3.

5. Composition according to one of claims 1 to 4, characterized in that the aldehyde groups of the aldehyde group-containing polymer are each bonded to an aromatic or heteroaromatic ring.

6. Composition according to one of claims 1 to 5, characterized in that the aldehyde group-containing polymer is a reaction product from the reaction of at least one hydroxyaldehyde with at least one isocyanate group-containing polymer.

7. Composition according to one of claims 1 to 6, characterized in that the compound having two or more thiol groups has 2 to 10, preferably 2 to 6, in particular 2 to 4, thiol groups.

8. Composition according to one of claims 1 to 7, characterized in that the compound having two or more thiol groups has a thiol equivalent weight of 65 to 800 g / eq, preferably 65 to 400 g / eq, in particular 80 to 300 g / eq.

9. Composition according to one of claims 1 to 8, characterized in that the compound having two or more thiol groups is selected from the group consisting of 1,8-dimercapto-3,6-dioxaoctane, 1,2-ethanediol di(2-mercaptoacetate), 1,4-butanediol di(2-mercaptoacetate), 1,1,1-trimethylolpropane tris(2-mercaptoacetate), pentaerythritol tetrakis(2-mercaptoacetate), 1,2-ethanediol di(3-mercaptopropionate), 1,4-butanediol di(3-mercaptopropionate), 1,1,1-trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), 3-mercapto-2-hydroxypro- pyl ethers of propoxylated pentaerythritol with an average thiol equivalent weight of 180 to 400 g / eq, tris(2-(3-mercaptopropionyloxy)ethyl)isocyanurate and mercapto group-containing polysulfide polymers with an average thiol equivalent weight of 250 to 800 g / eq.

10. Composition according to one of claims 1 to 9, characterized in that the ratio of the number of thiol groups to the number of aldehyde groups is in the range from 1.5 to 4, preferably 1.7 to 3, in particular 1.8 to 2.

5.

11. Composition according to one of claims 1 to 10, characterized in that at least one filler selected from aluminum oxide, aluminum hydroxide, zinc oxide and zinc hydroxide is contained, wherein the filler is a powdery substance which is solid at room temperature and is not soluble in the curable composition.

12. Composition according to one of claims 1 to 11, characterized in that at least one inorganic or organic acid or a compound hydrolyzable to an acid is present as catalyst.

13. Composition according to one of claims 1 to 12, characterized in that at least one mercaptosilane is contained as adhesion promoter.

14. Cured composition obtained from the curable composition according to any one of claims 1 to 13 after mixing the components.

15. Use of the composition according to any one of claims 1 to 13 as an elastic adhesive, elastic sealant or elastic coating, wherein the first and the second and optionally present further components are mixed together and the mixed composition is applied in the liquid state to at least one substrate.

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