Hardening components

Abstract

The present invention relates to a curable composition comprising a polymer having at least two isocyanate-reactive groups that can react with an isocyanate group, wherein at least one of these isocyanate-reactive groups is a CH-acidic group; a polyfunctional isocyanate having at least one isocyanate group; and an alkaline earth metal organyl catalyst.

Description

Technical Field

[0001] Adhesives form the backbone of modern joining processes and techniques. They are highly efficient as they can bond a very wide variety of materials by mechanical attachment even with a small application amount. Among countless different types of adhesives and bonding techniques, polyurethane-based adhesives are particularly suitable for numerous applications and, due to their chemical structure, are suitable for numerous different forms of adhesives, such as reactive hot melt adhesives, two-component adhesives or dispersion adhesives.

[0002] Similar to other reactive adhesive systems such as epoxy or silicone adhesives, polyurethane-based adhesives typically form very stable joints with high durability that can withstand any external environment (weather resistance, heat and cold, humidity, etc.), making them suitable for the most in-demand applications.

[0003] However, considering sustainability, there is a discussion about the joined components (bonded products) being recycled again at the end of their life cycle or being separable for repair purposes without causing significant damage to the components in, for example, electronic devices such as mobile phones or displays. For such recycling or separation, the adhesive had to be separable on demand (abbreviated as De-Bonding on Demand, DoD).

[0004] A common technique for de-bonding on demand is the introduction of temperature, which consequently affects the adhesive and / or cohesive forces. Various approaches exist in this regard, for example, by adding a non-reactively incorporated resin to the adhesive formulation, which "softens" the adhesive at temperatures above its softening point, thereby reducing its cohesive force (International Publication 2016 / 000222). However, this technique has disadvantages because the non-reactively incorporated polymer typically results in lower cohesive forces of the adhesive, even at lower temperatures during the phase / period of use. These can impair chemical resistance, lead to washing away, or cause undesirable migration.

[0005] Macromolecules, 2018, 51(3), pages 660-669 describes a reaction product of acetoacetoxyacrylate ester as a CH-acidic component with isocyanate for obtaining a thermally unstable radiation-crosslinkable crosslinking agent that enables the separation of radiation-curable adhesives on demand (by the action of heat). Malonate is also suitable as a CH-acidic component for the reaction with isocyanate, for example, in the form of a malonate-containing polyester as described in U.S. Patent No. 4,006,122.

[0006] The use of malonate-containing polyester for the manufacture of thermally stable adhesive systems is described in European Patent Application Publication No. 3636687. In this document, a blend of malonate-containing polyester and isocyanate-terminated polyester is prepared and subsequently analyzed for heat resistance. The reaction between the malonate-containing polyester and the isocyanate was carried out using zinc(II) acetylacetonate as a catalyst.

[0007] U.S. Patent Application Publication No. 2018 / 282575 discloses a curable coating composition comprising a polymer containing at least two active methylene functional groups; a polyisocyanate crosslinking agent; and a transition metal catalyst (barium sulfate and magnesium silica hydrate). Substrates at least partially coated with these coating compositions are further disclosed.

[0008] U.S. Patent No. 4,006,122 discloses a poly(esteramide) obtained by heating a hydroxyl-containing or hydroxyl-free polyester of malonic acid together with an organic polyisocyanate in the presence of a basic catalyst (calcium acetate). Crosslinking of the polyester occurs through the reaction of the isocyanate with the active hydrogen of the CH2 group of the malonate, generating an amide bond.

[0009] U.S. Patent No. 5,714,563 discloses a curable composition comprising an acetacetate-functional compound and a polyisocyanate-functional compound in the presence of calcium oxide.

[0010] Compared to the reaction between hydroxyl compounds and isocyanates, the relatively inert reactivity of CH-acidic compounds with isocyanates was a disadvantage in all the described reactions. In some cases, complete conversion was not achieved, or a catalyst or equimolar amounts of highly reactive reagents, such as sodium hydride or elemental sodium, had to be used to achieve complete conversion. This led to serious safety concerns and could cause many side reactions, such as hydrolysis of ester bonds.

[0011] Therefore, the object of the present invention was to provide a reaction system that ensures a rapid reaction with the highest possible selectivity for the target product and low safety concerns regarding the CH-acidic component and isocyanate.

[0012] The purpose of this is, a) A polymer having at least two isocyanate-reactive groups, wherein at least one of these isocyanate-reactive groups is a CH-acidic group, b) A polyfunctional isocyanate having at least one isocyanate group, c) At least one alkaline earth metal organyl catalyst in an amount of 0.005 mol% to 15 mol% based on the total molar amount of CH-acidic groups of polymer a), wherein the organyl is selected from the group consisting of alkoxides, 1,3-diketone-based complexes, or mixtures thereof, d) Optionally add further additives, polymers, fillers and It contains, The amounts of polymer a) and polyfunctional isocyanate b) used are selected in a curable composition such that the molar ratio of isocyanate reactive groups of polymer a) to isocyanate groups of polyfunctional isocyanate b) is 10:1 to 1:10.

[0013] In the context of the present invention, the term "isocyanate-reactive group" means several reactive groups that can react with an isocyanate group (NCO group).

[0014] Therefore, one aspect of the present invention is a composition as defined in the claims and the following description.

[0015] Another aspect of the present invention is a method for preparing a composition according to the present invention as defined in the claims and the following description.

[0016] Yet another aspect of the present invention is the use of the compositions according to the present invention for bonding substrates and as adhesives / sealants or coating materials.

[0017] The composition according to the present invention can achieve complete reaction and curing between isocyanate and CH-acidic component, has the advantage of not requiring the use of a catalyst where safety is of paramount importance, and the resulting cured system is preferably peelable at a temperature of less than 250°C.

[0018] The curable compositions according to the present invention, the methods for preparing them according to the present invention, and the uses of the curable compositions according to the present invention are described below as examples, without the intention to limit the present invention to these exemplary embodiments.

[0019] Where numbers are expressed as percentages below, they are weight percentages unless otherwise specified. Where average values, such as molar mass averages, are specified below, they are numerical averages unless otherwise specified. Where material properties, such as viscosity, are specified below, they are material properties at 25°C unless otherwise specified.

[0020] Component a) Component a) is a polymer a) having at least two isocyanate-reactive groups that can react with an NCO group (isocyanate group), and at least one of these isocyanate-reactive groups is a CH-acidic group.

[0021] According to the present invention, polymer a) corresponds to a polymer prepared by polymerizing a monomer composition comprising at least one CH-acidic compound, as described below, or is the product of a resulting reaction between a CH-acidic compound and an OH- and / or NH-functional polymer, as described below.

[0022] In the context of the present invention, a CH-acid compound should be understood to mean a compound that can release at least one proton from a carbon atom by a strong base. Preferably, the pKa (acid strength) of the CH-acid compound is in the range of 5 to 20.

[0023] In addition to the protons of the CH-acidic groups that can be released for reaction with the polyfunctional isocyanate b), the CH-acidic compounds preferably also have at least one further functional group that can be used for the covalent bonding of the CH-acidic compounds to polymers or functional molecules.

[0024] The CH-acidic compounds are preferably selected from the group consisting of malonic esters, acetoacetic esters, nitro compounds, nitriles, lactones or mixtures thereof. Usually, the released protons are in the alpha position of at least one functional group such as ketones, aldehydes, nitriles, nitro, esters, halides or sulfur. Preferably, the released protons are in the alpha position of at least two such functional groups.

[0025] The CH-acidic compounds are particularly preferably also malonic esters, acetoacetic esters and mixtures thereof.

[0026] Polymer a) contains at least one CH-acidic group, preferably two or more CH-acidic groups. These can be arranged at the chain ends of the polymer, within the polymer chain or both at the chain ends and within the polymer chain. More preferably, polymer a) contains between 2 and 30 covalently bonded CH-acidic groups.

[0027] However, polymer a) can also contain free OH groups. These free OH groups can arise, for example, by incorporating / copolymerizing polyglycols, preferably polyethylene glycol (PEG), OH-functional polybutadiene, polyesters, polyacrylates or hexanediol. These free OH groups can also react with isocyanates.

[0028] Polymer a) can also contain free NH groups. These free NH groups can arise, for example, from the incorporation / copolymerization of amine-terminated polyethers (Jeffamines) or polyamides. These free NH groups can also react with isocyanates.

[0029] An exemplary preparation of polymer a) is described in patent application EP3636687A1. The preparation is preferably carried out by melt condensation of an OH- and / or NH-functional polymer with a CH-acidic compound, typically involving the removal of a leaving group to effect the formation of a covalent bond between the CH-acidic compound and the OH- and / or NH-functional polymer.

[0030] The OH- or NH-functional polymer used can be any known corresponding polymer. OH-functional compounds in the context of the present invention are preferably OH-functional or OH-terminated polymers, such as polyesters, polybutadienes, polyethylene glycols or polypropylene glycols and mixtures thereof, poly-THF, polylactic acid, poly(meth)acrylates and non-polymeric compounds, such as ethylene glycol, propane-1,2-diol, trimethylene glycol, neopentyl glycol, butanediol, pentanediol, hexanediol or corresponding higher carbon analogs, glycerol, trimethylolpropane, pentaerythritol, cyclic alcohols, such as cyclohexanedimethanol or dicyclohexanediol and mixtures thereof. The OH-functional polymer is particularly preferably an OH-functional or OH-terminated polymer, and very particularly preferably an OH-terminated polymer.

[0031] NH-functional polymers within the context of the present invention are preferably polyesteramines or amine-terminated polyamides.

[0032] Polymer a) is preferably selected from the group consisting of polyester, polyether, poly(meth)acrylate, polybutadiene or mixtures thereof; more preferably polyester, polyether or mixtures thereof; even more preferably polyester or mixtures thereof.

[0033] The polymer a) of the curable composition is preferably a polymer having a number-average molecular weight of 500 to 50,000 g / mol according to DIN 55672-1, or a mixture thereof. In the present invention, the number-average molecular weight of polymer a) is determined by gel permeation chromatography (GPC) using a polystyrene calibration standard according to DIN 55672-1.

[0034] component b) Component b) is a polyfunctional isocyanate having at least one isocyanate group (NCO group).

[0035] Component b) of the curable composition is a polyfunctional isocyanate having at least one NCO group. Preferably, the polyfunctional isocyanate b) is selected from the group consisting of diisocyanates, triisocyanates, isocyanates-(meth)acrylates, isocyanatosilanes, or mixtures thereof.

[0036] Preferred isocyanatosilanes are 3-(trimethoxysilyl)propyl isocyanate and 3-(triethoxysilyl)propyl isocyanate.

[0037] In the context of the present invention, polyfunctional isocyanates may be compounds having at least one isocyanate group and further polymerizable functional groups, as well as compounds having at least two isocyanate groups. Polyfunctional isocyanates are preferably di- or triisocyanates, such as diphenylmethane-2,2'-diisocyanate, diphenylmethane-2,4'-diisocyanate, diphenylmethane-4,4'-diisocyanate, torylene-2,4-diisocyanate, torylene-2,6-diisocyanate, isophorone diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, as well as derivatives formed therefrom such as uretdione and isocyanurates, or mixtures thereof. Particularly preferred, the polyfunctional isocyanate is a diisocyanate, most preferably diphenylmethane-2,2'-diisocyanate.

[0038] According to the present invention, the amount of polymer a) and the amount of polyfunctional isocyanate b) used in the curable composition according to the present invention are selected such that the molar ratio of isocyanate-reactive groups of polymer a) to isocyanate groups of polyfunctional isocyanate b) is 10:1 to 1:10, preferably 8:1 to 1:8, and more preferably 5:1 to 1:5.

[0039] Ingredient c) Component c) is at least one alkaline earth metal organyl catalyst.

[0040] The composition according to the present invention contains at least one alkaline earth metal organyl catalyst in an amount of 0.005 mol% to 15 mol%, preferably 0.01 mol% to 10 mol%, more preferably 0.02 mol% to 5 mol%, and even more preferably 0.05 mol% to 3 mol%, based on the molar amount of CH-acidic groups of polymer a), wherein the organyl is selected from the group consisting of alkoxides, 1,3-diketone-based complexes, or mixtures thereof.

[0041] The alkaline earth metal organil catalyst c) is preferably selected from the group consisting of calcium, magnesium, or strontium organils or mixtures thereof, and more preferably selected from the group consisting of calcium alkoxides, magnesium alkoxides, strontium alkoxides, complexes of 1,3-diketones with calcium, magnesium, or strontium, or mixtures thereof.

[0042] Preferred complexes based on 1,3-diketones are acetylacetonate and its derivatives. More preferably, the complexes based on 1,3-diketones are selected from the group consisting of acetylacetonate, 2,2,6,6-tetramethyl-3,5-heptanedione, or mixtures thereof.

[0043] Particularly preferred alkoxides are selected from the group consisting of methoxides, ethoxides, propoxides, butoxides, 1,2-ethylene glycol alkoxides, propane-1,2-diol alkoxides, propane-1,3-diol alkoxides, butane-1,2-diol alkoxides, butane-1,3-diol alkoxides, butane-1,4-diol alkoxides, butane-2,3-diol alkoxides, and neopentyl alkoxides or mixtures thereof.

[0044] The most preferred alkaline earth metal organyl catalyst c) is selected from the group consisting of calcium methoxide, magnesium methoxide, strontium methoxide, calcium ethoxide, magnesium ethoxide, strontium ethoxide, magnesium acetylacetonate, calcium acetylacetonate, strontium acetylacetonate, bis(2,2,6,6-tetramethyl-3,5-heptanedionato)calcium, bis(2,2,6,6-tetramethyl-3,5-heptanedionato)magnesium, bis(2,2,6,6-tetramethyl-3,5-heptanedionato)strontium, strontium isopropoxide, or mixtures thereof.

[0045] Optional component d) Component d) corresponds to further additives, polymers, and / or fillers.

[0046] The curable composition according to the present invention may consist of components a), b), and c); however, it may also contain further components. In particular, not only further polymers, but also additives and / or fillers may be present in the curable composition.

[0047] "Further polymer" refers to a polymer different from polymer a). It is preferable to add a further OH- or NH-functional polymer that does not contain CH-acid functional groups, which can ensure curing by polyfunctional isocyanate and, if necessary, adjust thermal stability.

[0048] Furthermore, up to 50% by weight, preferably 5 to 40% by weight, of the total weight of the curable composition may be added, particularly additives, which ensure, for example, improved hydrolysis stability. These additives may be, for example, non-functionalized polymers, such as thermoplastic polyurethane (TPU) and / or polyacrylate and / or ethylene-vinyl acetate copolymer (EVA); pigments or fillers, such as talc, silicon dioxide, titanium dioxide, barium sulfate, calcium carbonate, carbon black, or colored pigments; tackifiers, such as rosin, hydrocarbon resins, phenolic resins, and aging stabilizers and auxiliary agents.

[0049] Method for preparing a curable composition There are various methods for preparing curable compositions. The most common method is mixing.

[0050] Mixing is preferably carried out at a temperature above room temperature, preferably above 30°C, more preferably between 50 and 130°C, and most preferably between 70 and 110°C. Depending on the properties of the adhesive being manufactured, mixing may be carried out in a molten material, a solvent, or water.

[0051] It may be advantageous to carry out the mixing under a protective gas atmosphere, for example, preferably under an inert gas or nitrogen atmosphere. This can help avoid undesirable reactions.

[0052] The mixing is preferably carried out for 0.1 to 360 minutes, more preferably for 15 to 180 minutes.

[0053] Use of the curable composition according to the present invention The compositions according to the present invention can be used to bond substrates, and preferably as adhesives, sealants, or coating materials. The bonds preferably include bonds that are separable (peelable) after curing by heat treatment at a temperature of 50 to 250°C, more preferably 90 to 200°C, even more preferably 110 to 190°C, and most preferably 110 to 170°C.

[0054] The compositions according to the present invention are particularly suitable for the manufacture of bonding parts for various substrates, such as plastics, fiber-reinforced plastics, metals, various types of wood, glass, glass-ceramics, concrete, mortar, brick, stone, foam, paper, and cardboard, and especially for bonding metal substrates, textiles, and various plastics.

[0055] The nature and degree of bonding are not limited. Preferably, the bonding is used in the wood and furniture industry (e.g., assembly bonding and lamination of decorative films to fiberboard), the automotive and transportation sector (e.g., door side components, interior roof linings, sheet manufacturing, retainer bonds, lamination of films or textiles to assembly bonds, and manufacturing of sandwich elements), the electronics industry, the construction industry (e.g., manufacturing of panels and doors), the shoe industry, the graphics industry and the textile industry, and in window structures (e.g., profile exteriors). Furthermore, the compositions according to the present invention are suitable as sealants and coating materials in the packaging industry.

[0056] The compositions according to the present invention are suitable for use in both one-component and two-component systems.

[0057] In the case of a one-component adhesive, the mixture is typically prepared at a much earlier time, unrelated to the application of the adhesive. After application of the adhesive according to the present invention, it hardens, for example, by moisture or by a heat-induced reaction of co-reactants present in the adhesive. In the case of a two-component adhesive, the mixture is prepared immediately before application of the adhesive.

[0058] The adhesive formulations (compositions) according to the present invention can be applied by all known methods, such as extruders, beads, nozzles, spreading, dipping, injecting, pouring, rolling, spraying, printing, wiping, washing, rolling, centrifugal separation, and powder (electrostatic). [Examples]

[0059] Preferred embodiments and examples should be construed as explanatory disclosures only, and not as limiting in any way.

[0060] The subject matter of the present invention will be described in more detail in the following embodiments, without the intention that the subject matter of the present invention is limited thereto.

[0061] Test method: 1.ATR infrared spectroscopy The decrease in free isocyanates was qualitatively analyzed using ATR-IR (Alpha II, Bruker) in samples collected throughout the reaction process.

[0062] 2.Molecular weight distribution The number-average molecular weight of the polyesters used in the examples is determined by gel permeation chromatography in tetrahydrofuran as the eluent and polystyrene for calibration, according to DIN 55672-1.

[0063] Catalyst evaluation: General Procedure: A specified amount of catalyst, followed by dimethyl malonate, was packed into a Radleys® 20 mL reaction tube at room temperature. The reaction tube was purged with nitrogen, and then a specified amount of phenyl isocyanate was added. The mixture was then stirred for the specified time and temperature, and the residual NCO was analyzed after the reaction time was complete. Qualitative ATR-IR measurement was used to evaluate the catalyst activity as follows:

[0064] [Table 1]

[0065] [Table 2]

[0066] Conclusion: Some catalysts were found not to react despite a large molar excess of dimethylmalonate relative to the isocyanate. Some catalysts exhibited temperature-dependent activity, for example, in test series 1-5, 1-6, or 1-10. Catalysts in test series 1-1, 1-2, 1-3, and 1-7 showed excellent activity at all temperatures under given conditions.

[0067] [Table 3]

[0068] Conclusion: In the second test series, the significantly lower excess amount of malonate relative to isocyanate and the resulting low catalytic load led to the finding that only catalysts from test series 2-1 and 2-5 exhibited high activity across the entire temperature range. Catalysts from test series 2-2, 2-3, 2-4, and 2-6 were temperature-dependent, while catalyst 2-7 showed no activity.

[0069] [Table 4]

[0070] Conclusion: At substantially equimolar ratios and lower catalyst amounts of 2 mol%, at higher temperatures, only the catalysts from Test Series 3-4 exhibited very high activity, while all other candidates showed a considerable amount of residual isocyanate. At low temperatures, none of the catalysts achieved a complete reaction. This indicates that the calcium methoxide of the catalyst has significantly higher activity compared to the other catalysts.

[0071] [Table 5]

[0072] Conclusion: As further representative examples of alkaline earth metal catalysts, both calcium acetylacetonate and strontium isopropoxide clearly exhibit higher reactivity than comparable alkali metal catalysts (Test Series 3).

[0073] [Table 6]

[0074] Conclusion: Even with inherently unreactive systems such as aliphatic isocyanates, alkaline earth metal catalysts, particularly alkaline earth metal alkoxides, exhibit significantly higher reactivity compared to other catalysts.

[0075] Test 6: Preparation of reaction adducts between phenyl isocyanate and dimethyl malonate Weigh the catalyst (5 mol%), 1.19 g of phenyl isocyanate (10 mmol), and 1.32 g of dimethyl malonate (10 mmol) into a 20 mL reaction tube under nitrogen. Then, heat the mixture under reflux at 70°C for 2 hours.

[0076] Analysis using ATR-IR showed no residual NCO band, which means that the complete reaction of phenyl isocyanate was confirmed.

[0077] Unpurified reaction mixture 11H NMR analysis reveals both the desired product and side reactions such as trimerized phenyl isocyanate. The proportion of unreacted dimethylmalonate compared to the product indicates the selectivity of the reaction, and it is, of course, desirable that the proportion of remaining dimethylmalonate be minimized.

[0078] [Table 7]

[0079] Conclusion: Alkaline earth metal alkoxides exhibit considerably high selectivity in the reaction of CH-acidic compounds with isocyanates for the desired target product, and therefore clearly result in fewer isocyanate side reactions.

[0080] Test Series 7: Reaction of malonic acid ester-containing polyester with diphenylmethane-4,4'-diisocyanate (MDI) Polyester used, prepared in accordance with prior art (European Patent Application Publication No. 3636687): P1: A linear hexanediol adipate with a malonate-terminated group and a number-average molecular weight of 4000 g / mol; functional value = 2, equivalent to 2000 mg / mmol of malonate. P2: A linear hexanediol malonate with a malonate-terminated group and a number-average molecular weight of 2100 g / mol; average functional value of approximately 10, equivalent to 210 mg / mmol of malonate.

[0081] Composition 1: 50 g of polyester P1 (25 mmol malonate) was melted at 90°C in a 100 mL round-bottom flask equipped with a mechanical stirrer. Then, 25 mg of Ca(OMe)2 (1 mol% relative to malonate) and 2.5 g of diphenylmethane-4,4'-diisocyanate (NCO2 20 mmol) were added under nitrogen as catalysts, and the mixture was stirred for 3 hours. Analysis by ATR-IR showed no residual isocyanate groups. A thermoplastic material was obtained. Molar ratio of CH-acidic groups in polymer a) to isocyanate groups in polyfunctional isocyanate b): 1.25:1

[0082] Composition 2: 50 g of polyester P1 (25 mmol malonate) was melted at 90°C in a 100 mL round-bottom flask equipped with a mechanical stirrer. Then, 51 mg of Sr(OiPr)2 (1 mol% relative to malonate) and 2.5 g of diphenylmethane 4,4'-diisocyanate (NCO2 20 mmol) were added under nitrogen as catalysts, and the mixture was stirred for 3 hours. Analysis by ATR-IR showed no residual isocyanate groups. A thermoplastic material was obtained. Molar ratio of CH-acidic groups in polymer a) to isocyanate groups in polyfunctional isocyanate b): 1.25:1

[0083] Composition 3: 42 g of polyester P2 (200 mmol of malonate) was melted at 90°C in a 100 mL round-bottom flask equipped with a mechanical stirrer. Then, 204 mg of Ca(OMe)2 (1 mol% relative to malonate) and 7.5 g of diphenylmethane-4,4'-diisocyanate (60 mmol of NCO, 30% NCO relative to malonate) were added as catalysts, and the mixture was stirred at 90°C for 1 hour. Analysis by ATR-IR showed no residual isocyanate groups. A highly crosslinked, insoluble material was obtained. Melting tests in an oven showed that the material could be melted at approximately 150°C. Molar ratio of CH-acidic groups in polymer a) to isocyanate groups in polyfunctional isocyanate b): 3.3:1

[0084] Conclusion: The reaction between CH-acidic groups and isocyanates functions well even in polymer systems, and it is clear that it is possible to obtain both thermoplastic systems through chain extension and thermosetting systems through crosslinking.

[0085] In the case of thermosetting systems, it was found that the system can be remelted due to the thermally unstable reaction products. This is possible, if any, in conventional thermosetting systems only at extremely high temperatures.

Claims

1. a) A polymer having at least two isocyanate-reactive groups, wherein at least one of these isocyanate-reactive groups is a CH-acidic group, b) A polyfunctional isocyanate having at least one isocyanate group, c) A catalyst comprising at least one alkaline earth metal organyl catalyst in an amount of 0.005 mol% to 15 mol% based on the molar amount of CH-acidic groups of polymer a), wherein the organyl is selected from the group consisting of alkoxides, 1,3-diketone-based complexes, or mixtures thereof, d) Optionally add further additives, polymers, fillers and It contains, A curable composition in which the amount of polymer a) and the amount of polyfunctional isocyanate b) used are selected such that the molar ratio of isocyanate-reactive groups of polymer a) to isocyanate groups of polyfunctional isocyanate b) is 10:1 to 1:

10.

2. The curable composition according to claim 1, characterized in that the alkaline earth metal organil catalyst is calcium organil, magnesium organil, or strontium organil, or a mixture thereof.

3. The curable composition according to claim 2, characterized in that the alkaline earth metal organyl catalyst is selected from the group consisting of calcium alkoxide, magnesium alkoxide, strontium alkoxide, a complex of 1,3-diketone with calcium, magnesium, or strontium, or a mixture thereof.

4. The curable composition according to any one of claims 1 to 3, characterized in that the polyfunctional isocyanate b) is selected from the group consisting of diisocyanate, triisocyanate, isocyanate-(meth)acrylate, isocyanatosilane, or mixtures thereof.

5. The curable composition according to any one of claims 1 to 4, characterized in that the polymer a) has a number-average molecular weight of 500 to 50,000 g / mol according to DIN 55672-1.

6. The curable composition according to any one of claims 1 to 5, characterized in that the CH-acidic group in polymer a) is at least one covalently bonded malonic acid ester or acetoacetate ester.

7. The curable composition according to any one of claims 1 to 6, characterized in that the polymer a) contains 2 to 30 covalently bonded CH-acidic groups, preferably malonic acid esters, acetoacetic acid esters, or mixtures thereof.

8. The curable composition according to any one of claims 1 to 7, characterized in that the polymer a) is selected from the group consisting of polyester, polyether, poly(meth)acrylate, OH-functional polybutadiene, or mixtures thereof.

9. The curable composition according to any one of claims 1 to 8, characterized in that the molar ratio of isocyanate-reactive groups of polymer a) to isocyanate groups of polyfunctional isocyanate b) is 8:1 to 1:8, more preferably 5:1 to 1:

5.

10. The curable composition according to any one of claims 1 to 9, characterized in that the catalyst c) is used in an amount of 0.01 mol% to 10 mol%, preferably 0.02 mol% to 5 mol%, and more preferably 0.05 mol% to 3 mol%, based on the molar amount of CH-acidic groups of polymer a).

11. A method for preparing a curable composition according to any one of claims 1 to 10, characterized in that the mixing is carried out at a temperature of room temperature or higher, preferably above 30°C, more preferably between 50 and 130°C, and most preferably between 70 and 110°C.

12. The method according to claim 11, characterized in that the mixing is carried out over a period of 0.1 to 360 minutes, preferably 15 to 180 minutes.

13. A sealing and adhesive compound and a coating material containing the curable composition according to any one of claims 1 to 10.

14. Use of the curable composition according to any one of claims 1 to 10, preferably as an adhesive, sealant, or coating material for bonding substrates.

15. The use according to claim 14, characterized in that the bond includes a bond that can be separated by heat treatment at a temperature of 50 to 250°C, preferably 110 to 190°C.

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