Mercapto-functional adduct of trimercaptan and isocyanate-group-containing polymer

Abstract

The invention relates to a mercapto-functional adduct from the reaction of at least one mercaptan M having at least three mercapto groups with at least one isocyanate-group-containing polymer having an average molecular weight Mn of at least 1000 g / mol in a ratio of the number of mercapto groups to the number of isocyanate groups at the start of the reaction of at least 4. The adduct makes it possible to produce epoxy resin adhesives with good workability, rapid curing, good adhesion properties and a surprising combination of high strength and high impact resistance.

Description

[0001] MERCAPTO-FUNCTIONAL ADDUCT OF TRIMERCAPTAN AND ISOCYANAT GROUP-CONTAINING POLYMER

[0002] Technical field

[0003] The invention relates to mercapto-functional adducts from the reaction of polymercaptans with isocyanate group-containing polymers and their use in curable compositions, in particular in adhesives, sealants and coatings.

[0004] State of the art

[0005] Polymercaptans are known as hardeners in curable compositions, especially in room temperature curable epoxy resin adhesives, where they enable particularly fast curing.

[0006] Epoxy adhesives offer high bond strength on various substrates. However, they are typically not very elastic and have low impact resistance. For applications requiring high impact strength or where strong vibrations and movements occur, conventional epoxy adhesives are often too brittle. For such applications, so-called impact-modified (toughened) epoxy products have been developed, for example, for bonding in vehicle bodies requiring high crash resistance. In these products, the cured adhesive contains finely dispersed, flexible polymers bonded to the epoxy matrix as an impact modifier or toughener. These polymers absorb mechanical energy during a crash and can thus significantly reduce crack propagation in the adhesive.For example, functionalized liquid rubber such as ATBN (amine-terminated butadiene-acrylonitrile copolymer) or ETBN (epoxy-terminated butadiene-acrylonitrile copolymer) is known as a toughener, but these are highly viscous and expensive and have disadvantages in terms of low-temperature flexibility.

[0007] US 2021 / 0198537 describes metals bonded using a toughened epoxy resin adhesive. Among the impact modifiers (tougheners) described are polyurethanes, particularly isocyanate-containing polymers, which are blocked with an epoxy resin or with cardanol. Such adhesives exhibit high low-temperature flexibility. However, the epoxy-blocked tougheners are very viscous, and in the case of cardanol-blocked tougheners, cardanol is released during curing, which can have an undesirable softening effect in the cured adhesive and migrate out of the adhesive. US 3,114,734 describes the reaction of dimercaptans with isocyanate-containing polymers and the curing of the resulting adducts by oxidation.

[0008] US 7'847'034 describes the reaction of a dimercaptan with isocyanate group-containing polymers and its use in epoxy resin adhesives.

[0009] Description of the invention

[0010] The object of the present invention is to provide a hardener that can be used as an impact modifier for epoxy resin adhesives and that overcomes the disadvantages of the prior art with regard to high viscosity and released releasers.

[0011] Surprisingly, this problem is solved with a mercapto-functional adduct as described in claim 1. The adduct is obtained from the reaction of at least one mercaptan M with at least three mercapto groups with an isocyanate-containing polymer.

[0012] The adduct according to the invention can be produced in a simple process from readily available, inexpensive raw materials. It is stable during storage and is liquid and low-viscosity, particularly at room temperature. This makes it especially easy to use as a hardener and / or impact modifier for epoxy resin compositions, as well as a hardener for compositions containing other reactive groups that are reactive towards mercapto groups, such as, in particular, isocyanate groups, acrylate groups, or aromatic aldehyde groups.

[0013] The adduct according to the invention is particularly suitable as a component of a hardener for epoxy resins. The adduct enables good processability, rapid curing, and a surprising combination of high strength and high impact resistance. In particular, it allows for epoxy resin adhesives with surprisingly high impact resistance without significant reductions in curing speed, final hardness, tensile strength, modulus of elasticity, or adhesion properties. Compared to corresponding adducts with dimercaptan instead of mercaptan M, the adduct according to the invention offers significantly higher strength.

[0014] Further aspects of the invention are the subject of further independent claims. Particularly preferred embodiments of the invention are the subject of dependent claims. Ways of carrying out the invention

[0015] The invention relates to a mercapto-functional adduct resulting from the implementation of

[0016] - at least one mercaptan M with at least three mercapto groups with

[0017] - at least one isocyanate-containing polymer with an average molecular weight M n of at least 1,000 g / mol, in a ratio of the number of mercapto groups to the number of isocyanate groups at the start of the reaction of at least 4.

[0018] The term "molecular weight" refers to the molar mass (in grams per mole) of a molecule. The "mean molecular weight" is the number-average molecular weight M. n It is defined as a polydisperse mixture of oligomeric or polymeric molecules. It is determined by gel permeation chromatography (GPC) against polystyrene as a standard.

[0019] The "NCO content" refers to the percentage of isocyanate groups by weight. The "mercapto equivalent weight" refers to the mass of a compound or composition containing mercapto groups that contains one mole equivalent of mercapto groups. It is expressed in the unit "g / eq".

[0020] An adduct or composition is described as "storage-stable" if it can be stored at room temperature in a suitable container for an extended period, typically at least 3 months up to 6 months or more, without its application or performance characteristics being altered by storage to an extent relevant to its use. Substance names beginning with "poly," such as polyaldehyde, polyisocyanate, polyol, polyepoxide, or polyamine, denote substances that formally contain two or more of the functional groups appearing in their name per molecule.

[0021] A "primary amine group" is an amine group that is bonded to a single organic residue and carries two hydrogen atoms; a "secondary amine group" is an amine group that is bonded to two organic residues, which may also be part of a ring together, and carries one hydrogen atom; and a "tertiary amine group" is an amine group that is bonded to three organic residues, which may also be part of one or more rings in pairs or groups of three, and carries no hydrogen atom.

[0022] The hydrogen atoms of primary and secondary amine groups are referred to as "hydrogen amines." The "hydrogen amine equivalent weight" is the mass of an amine or an amine-containing composition that contains one molecular equivalent of hydrogen amines. It is expressed in the unit "g / eq".

[0023] The term "epoxide equivalent weight" refers to the mass of an epoxy compound or composition containing one mole equivalent of epoxy groups. It is expressed in the unit "g / eq".

[0024] A temperature of 23 °C is referred to as "room temperature".

[0025] All industry standards and norms mentioned in the document refer to the versions valid at the time of the initial application.

[0026] Weight percent (wt%) denotes 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 total reaction product from the reaction of mercaptan M with the isocyanate-containing polymer is referred to in this document as the mercapto-functional adduct. It typically contains a mixture of mercapto-functional polymer and unreacted mercaptan M.

[0028] The mercapto-functional adduct according to the invention is in particular free of isocyanate groups.

[0029] The mercapto-functional adduct according to the invention is stable in storage.

[0030] In the case of a mercaptan M with three mercapto groups and a linear isocyanate group-containing polymer, the adduct according to the invention contains, in addition to unreacted mercaptan M, mainly the following adduct molecules of formula (I) and (II), where P represents the remainder of the isocyanate group-containing polymer after removal of two isocyanate groups and E represents the remainder of the mercaptan M after removal of the three mercapto groups.

[0031] An adduct molecule of formula (I) is also called a "monoadduct". It contains only one P residue. An adduct molecule of formula (II) is also called a "diadduct". It contains two P residues. Additionally, the adduct also contains more highly adducted components in which more than two P residues are adducted via mercaptan M.

[0032] A high ratio of the number of mercapto groups to the number of isocyanate groups corresponds to a high excess of mercaptan M and favors a high content of monoadduct of formula (I) and a comparatively high content of unreacted mercaptan M.

[0033] A lower ratio of the number of mercapto groups to the number of isocyanate groups corresponds to a lower excess of mercaptan M and favors a higher content of more highly adducted components and a lower content of unreacted mercaptan M.

[0034] Preferably, the ratio of the number of mercapto groups to the number of isocyanate groups at the beginning of the reaction is in the range of 4 to 30, preferably 4.5 to 20, more preferably 5 to 10, and particularly 6 to 9. Such an adduct is particularly suitable for the uses described.

[0035] In the case of a mercaptan M with three mercapto groups, the ratio is preferably between 5 and 10. This typically corresponds to a ratio of the number of trimercaptan molecules to the number of isocyanate groups of 1.7 to 3.3.

[0036] In the case of a mercaptan M with four mercapto groups, the ratio of the number of mercapto groups to the number of isocyanate groups is preferably between 5 and 15, particularly between 6.7 and 13. This typically corresponds to a ratio of the number of tetramercaptan molecules to the number of isocyanate groups of 1.3 to 3.8, particularly between 1.7 and 3.3.

[0037] Preferably, the mercaptan M has three or four, in particular three, mercapto groups. Preferably, the mercaptan M has a mercapto equivalent weight of 45 to 400 g / eq, in particular 100 to 300 g / eq.

[0038] Preferably, the mercaptan M is free of hydroxyl groups.

[0039] Bevorzugt ist das Mercaptan M ausgewählt ist aus der Liste bestehend aus Glycerol- tris(2-mercaptoacetat), Glycerol-tris(3-mercaptopropionat), Glycerol-tris(3- mercaptobutylat), 1 , 1 , 1 -T rimethylolpropan-tris(2-mercaptoacetat), 1 ,1 ,1- T rimethylolpropan-tris(3-mercaptopropionat), 1 , 1 , 1 -T rimethylolpropan-tris(3- mercaptobutyrat), Pentaerythritol-tris(2-mercaptoacetat), Pentaerythritol-tris(3- mercaptopropionat), Pentaerythritol-tris(3-mercaptobutyrat), Pentaerythritol-tetrakis(2- mercaptoacetat), Pentaerythritol-tetrakis(3-mercaptopropionat), Pentaerythritol- tetrakis(3-mercaptobutyrat), 3-Mercapto-2-hydroxypropylether von propoxyliertem Pentaerythritol mit einem mittleren Mercapto-Equivalentgewicht von 180 bis 400 g / eq, bevorzugt 180 bis 300 g / eq, Tris(2-(2-mercaptoacetyloxy)ethyl)isocyanurat, Tris(2-(3- mercaptopropionyloxy)ethyl)isocyanurat und Tris(2-(3- mercaptobutanoyloxy)ethyl)isocyanurat.

[0040] Preferred of these are glycerol tris(3-mercaptopropionate), 1,1,1-trimethylolpropane tris(2-mercaptoacetate), 1,1,1-trimethylolpropane tris(3-mercaptopropionate) or 1,1,1-trimethylolpropane tris(3-mercaptobutyrate), in particular trimethylolpropane tris(3-mercaptopropionate).

[0041] Preferably, the isocyanate-containing polymer has a medium molecular weight M n from 1,000 to 15,000 g / mol, especially 1,500 to 10,000 g / mol.

[0042] Preferably, the isocyanate-containing polymer has an NCO content of 1 to 9 wt%, more preferably 1.5 to 6.5 wt%. The NCO content is determined in particular by reacting the isocyanate groups with an excess of dibutylamine and back-titration of the unreacted dibutylamine with aqueous hydrochloric acid.

[0043] Preferably, the isocyanate-containing polymer has an average isocyanate functionality of 1.5 to 4, particularly preferably 1.7 to 3, and especially 1.8 to 2.0. Preferably, the isocyanate-containing polymer has an average isocyanate functionality of 1.7 to 3, particularly 1.8 to 2.0, and an NCO content of 1.5 to 6.5 wt%.

[0044] Preferably, the isocyanate group-containing polymer contains a polyether, polyester or hydrocarbon backbone, particularly preferably a polyether or a hydrocarbon backbone, most preferably a polyether backbone.

[0045] A polyether backbone is preferably a poly(oxy-1,4-butylene) or a poly(oxy-1,3-propylene) or a poly(oxy-1,2-propylene) backbone, wherein a poly(oxy-1,2-propylene) backbone may additionally contain oxy-1,2-ethylene units, particularly at the chain ends.

[0046] Preferably, the isocyanate-containing polymer is liquid at room temperature, particularly with a viscosity at 20 °C of 0.2 to 500 Pa s, preferably 0.5 to 300 Pa s, particularly 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. -1 .

[0047] Preferably, the isocyanate group-containing polymer is a reaction product of at least one monomeric diisocyanate with at least one polymeric polyol in a molar NCO / OH ratio of at least 1.5, preferably at least 1.8, preferably under exclusion of moisture at 20 to 160 °C, in particular 40 to 140 °C, optionally in the presence of a suitable catalyst.

[0048] A molar NCO / OH ratio of 1.5 / 1 to 10 / 1 is preferred, preferably 1.8 / 1 to 7 / 1, wherein unreacted monomeric diisocyanates have optionally been removed from the polymer.

[0049] In a preferred embodiment of the invention, the molar NCO / OH ratio is in the range of 1.5 / 1 to 2.5 / 1, particularly 1.8 / 1 to 2.2 / 1. In this case, unreacted monomeric diisocyanates are preferably not removed from the polymer. Such an adduct according to the invention typically contains approximately 0.7 to 5 wt% reaction products of monomeric diisocyanate and mercaptan M. In a further preferred embodiment of the invention, the molar NCO / OH ratio is in the range of 3 / 1 to 10 / 1, particularly 4 / 1 to 8 / 1. In this case, unreacted monomeric diisocyanates are preferably removed from the resulting polymer by a suitable separation process, in particular by distillation, particularly to a content of less than 0.5 wt%, preferably less than 0.2 wt%, based on the isocyanate-containing polymer.Preferably, the monomeric diisocyanate is removed from the obtained polymer by thin-film distillation or short-path distillation under vacuum.

[0050] The content of monomeric diisocyanate is preferably determined by HPLC chromatography after prior derivatization using N-propyl-4-nitrobencylamine with 0.04 M sodium acetate / acetonitrile as mobile phase and detection using a photodiode array.

[0051] Such an isocyanate-containing polymer has a particularly narrow molecular weight distribution and a particularly low viscosity. It enables adducts according to the invention with a particularly low content of reaction products of monomeric diisocyanate and mercaptan M, wherein such an adduct enables epoxy resin products with particularly high strength and / or elongation.

[0052] Preferably, the monomeric diisocyanate is selected from the list consisting of 1,6-hexane diisocyanate (HDI), 2,2(4),4-trimethyl-1,6-hexane diisocyanate (TMDI), 1-methyl-2,4(6)-diisocyanatocyclohexane, isophorone diisocyanate (IPDI), 4,4'-diisocyano-natodicyclohexylmethane, 4(2),4'-diphenylmethane diisocyanate (MDI) and 2,4(6)-toluene diisocyanate (TDI).

[0053] HDI, IPDI or MDI is particularly preferred, especially IPDI or MDI.

[0054] The polymeric polyols are preferred

[0055] - Polyether polyols, in particular polyoxyalkylene diols or polyoxyalkylene triols, in particular polymerization products of 1,2-propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, oxetane or tetrahydrofuran, optionally using ethylene oxide, wherein these are optionally polymerized by means of a starter molecule with two or more active hydrogen atoms.

[0056] Preferred polyether polyols are poly(oxy-1,4-butylene)diols, also called polytetrahydrofurans, poly(oxy-1,3-propylene)diols, poly(oxy-1,2-propylene)diols, poly(oxy-1,2-propylene)triols, or ethylene oxide-terminated (EO-endcapped) poly(oxy-

[0057] 1,2-propylene)diols or triols. The latter are obtained by further alkoxylation of poly(oxy-1,2-propylene)diols or triols with ethylene oxide after completion of the polypropoxylation reaction, thereby ultimately exhibiting primary hydroxyl groups. They contain, in particular, up to 25 wt% oxy-

[0058] 1,2-ethylene units based on the total polyol.

[0059] Preferred polyether polyols have a degree of unsaturation of less than 0.02 mEq / g, in particular less than 0.01 mEq / g.

[0060] - Polyester polyols from the polycondensation of dicarboxylic acids with di- or trihydric alcohols, in particular adipic acid, sebacic acid, dodecanedicarboxylic acid or a dimer fatty acid, with di- and / or trioyls such as in particular 1,6-hexanediol, neopentyl glycol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, trimethylolpropane, glycerol or castor oil.

[0061] - Polyhydroxy functional fats or oils, especially 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).

[0062] - Polyetherpolyesterpolyols.

[0063] - Polyhydrocarbon polyols, especially hydrogenated polybutadiene polyols.

[0064] Liquid polymeric polyols at room temperature are preferred.

[0065] Preferably, the polymeric polyol has an OH number of 12 to 175 mg KOH / g, preferably 18 to 120 mg KOH / g, in particular 25 to 60 mg KOH / g.

[0066] Preferably the polymeric polyol is selected from the list consisting of polyether polyols, polyester polyols and hydrocarbon polyols.

[0067] Polyether polyols or polyhydrocarbon polyols, especially polyether polyols, are preferred.

[0068] Particularly preferred are poly(oxy-1,4-butylene)diols, poly(oxy-1,3-propylene)diols, poly(oxy-1,2-propylene)diols, poly(oxy-1,2-propylene)triols or ethylene oxide-terminated (EO-endcapped) poly(oxy-1,2-propylene)diols or triols.

[0069] The reaction of mercaptan M with the isocyanate group-containing polymer to form the adduct according to the invention preferably takes place at a temperature of 10 to 100 °C, in particular 15 to 80 °C, preferably in the presence of a basic catalyst such as triethylamine.

[0070] Preferably, the mercaptan M is initially added, and the isocyanate-containing polymer is slowly added with thorough stirring. Alternatively, the mercaptan M and the isocyanate-containing polymer can be mixed, followed by the addition of a basic catalyst. Furthermore, the reaction to form the adduct can be carried out in a continuous process.

[0071] The reaction is complete when the reaction product is free of isocyanate groups. The decrease in the isocyanate group content can be monitored, in particular, by titrimetric analysis or infrared spectroscopy.

[0072] Preferably, the process is carried out without the use of organic solvents.

[0073] The reaction yields the mercapto-functional adduct according to the invention. As already mentioned, it contains a mixture of unreacted mercaptan M and adducted molecules in which mercaptan M is adducted to isocyanate groups via thiourethane bonds.

[0074] The type of isocyanate-containing polymer used and the ratio of the number of mercapto groups to the number of isocyanate groups primarily determine the composition of the resulting adduct. An isocyanate-containing polymer with an isocyanate functionality greater than two leads to a high mercapto functionality of the adduct. Furthermore, an isocyanate-containing polymer with a broad molar mass distribution and a high content of monomeric diisocyanates yields an adduct with a different composition than an isocyanate-containing polymer with a narrow molar mass distribution and a low content of monomeric diisocyanates. The properties of the adduct according to the invention can thus be specifically influenced by varying the mercaptan M, the isocyanate-containing polymer used, and the stoichiometric ratio during the reaction.

[0075] Surprisingly, it has been shown that an adduct starting from a mercaptan M with at least three mercapto groups, when used in epoxy resin compositions, enables particularly high strength and impact resistance. Preferably, the adduct according to the invention contains less than 5 parts by weight, preferably less than 1 part by weight, and in particular less than 0.5 parts by weight, of volatile organic solvents with a boiling point at atmospheric pressure of less than 250 °C, based on 100 parts by weight of reaction product from mercaptan M and isocyanate-containing polymer. Such an adduct causes particularly low emissions.

[0076] Preferably, the adduct is liquid and low-viscosity at room temperature. In particular, the adduct has a viscosity at 20 °C of 1 to 500 Pa s, preferably 2 to 3000 Pa s, and more specifically 3 to 250 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. -1 .

[0077] Preferably, the adduct according to the invention has an average mercapto equivalent weight of 150 to 1,500 g / eq, in particular 200 to 1,000 g / eq. The mercapto equivalent weight can be calculated from the mercapto equivalent weight of the mercaptan M used and the NCO content of the isocyanate-containing polymer, or it can be determined using a suitable analytical method.

[0078] The mercapto-functional adduct according to the invention is advantageously usable for curing compounds with at least two reactive groups that are reactive towards mercapto groups.

[0079] The mercapto-functional adduct according to the invention can be further used by hardening it with the aid of a suitable catalyst under oxidation and formation of disulfide groups.

[0080] Another object of the invention is the use of the mercapto-functional adduct according to the invention as a hardener in a hardenable composition containing reactive groups selected from epoxide group, isocyanate group, aldehyde group, vinyl group, allyl group, acrylate group and methacrylate group.

[0081] Aromatic aldehyde groups bonded to an aromatic or heteroaromatic carbon atom are preferred as the aldehyde group. Polyaldehydes with two or more aldehyde groups, such as terephthalaldehyde, isophthalaldehyde, or phthalaldehyde, or reaction products of polyisocyanates, especially isocyanate-containing polymers, with hydroxyaldehydes, such as 5-hydroxymethylfurfural, ethoxylated salicylaldehyde, particularly 2-(2-hydroxyethoxy)benzaldehyde, or ethoxylated vanillin, particularly 4-(2-hydroxyethoxy)-3-methoxybenzaldehyde, are preferred. Such curable compositions cure with the adduct according to the invention in the presence of an acidic catalyst, such as p-dodecylbenzenesulfonic acid, forming a solid polymer with the formation of thioacetal groups.

[0082] The adduct according to the invention is particularly preferably used in a curable composition containing epoxy groups. It enables the production of flexible or impact-modified epoxy resin products with good processability at ambient temperatures, rapid curing, and high final hardness and strength.

[0083] Another object of the invention is therefore an epoxy resin composition comprising at least one epoxy resin and at least one hardener for epoxy resins containing at least one mercapto-functional adduct as described above.

[0084] A suitable epoxy resin is obtained in particular from the reaction of epichlorohydrin with polyols, polyphenols or amines, or from the oxidation of olefins.

[0085] Aromatic epoxy resins are preferred, especially the glycidyl ethers of

[0086] - Bisphenol A, bisphenol F, or bisphenol A / F, where A stands for acetone and F for formaldehyde, which served as starting materials for the production of these bisphenols. In the case of bisphenol F, positional isomers may also be present, in particular derived from 2,4'- or 2,2'-hydroxyphenylmethane.

[0087] - Dihydroxybenzene derivatives such as resorcinol, hydroquinone or pyrocatechol,

[0088] - other bisphenols or polyphenols such as bis(4-hydroxy-3-methylphenyl)methane, 2,2-bis(4-hydroxy-3-methylphenyl)propane (bisphenol C), bis(3,5-dimethyl-4-hydroxyphenyl)methane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-tert.butylphenyl)propan, 2,2- Bis(4-hydroxyphenyl)butan (Bisphenol B), 3,3-Bis(4-hydroxyphenyl)pentan, 3,4- Bis(4-hydroxyphenyl)hexan, 4,4-Bis(4-hydroxyphenyl)heptan, 2,4-Bis(4- hydroxyphenyl)-2-methylbutan, 2,4-Bis(3,5-dimethyl-4-hydroxyphenyl)-2- methylbutan, 1 ,1-Bis(4-hydroxyphenyl)cyclohexan (Bisphenol Z), 1 ,1-Bis(4- hydroxyphenyl)-3,3,5-trimethylcyclohexan (Bisphenol TMC), 1 ,1 -Bis(4- hydroxyphenyl)-1-phenylethan, 1 ,4-Bis[2-(4-hydroxyphenyl)-2-propyl]benzol (Bisphenol P), 1 ,3-Bis[2-(4-hydroxyphenyl)-2-propyl]benzol (Bisphenol M), 4,4'- Dihydroxydiphenyl (DOD), 4,4'-Dihydroxybenzophenon, Bis(2-hydroxynaphth-1- yl)methan, Bis(4-hydroxynaphth-1-yl)methan, 1 ,5-Dihydroxynaphthalin, Tris(4- hydroxyphenyl)methan, 1 ,1 ,2,2-Tetrakis(4-hydroxyphenyl)ethan, Bis(4- hydroxyphenyl)ether oder Bis(4-hydroxyphenyl)sulfon,.

[0089] - Novolaks, which are in particular condensation products of phenol or cresols with formaldehyde or paraformaldehyde or acetaldehyde or crotonaldehyde or isobutyraldehyde or 2-ethylhexanal or benzaldehyde or furfural,

[0090] - aromatic amines, such as aniline, toluidine, 4-aminophenol, 4,4'-methylenediphenyldiamine, 4,4'-methylenediphenyldi-(N-methyl)amine, 4,4'-[1,4-phenylene-bis(1-methylethylidene)]bisaniline (Bisaniline P) or 4,4'-[1,3-phenylene-bis(1-methylethylidene)]bisaniline (Bisaniline M).

[0091] Other suitable epoxy resins are aliphatic or cycloaliphatic polyepoxides, in particular

[0092] - Glycidyl ethers of saturated or unsaturated, branched or unbranched, cyclic or open-chain di-, tri- or tetrafunctional C2 to Cso alcohols, in particular ethylene glycol, propylene glycol, butylene glycol, hexanediol, octanediol, polypropylene glycols, dimethylolcyclohexane, neopentyl glycol, dibromoneopentyl glycol, castor oil, trimethylolpropane, trimethylolethane, pentaerythrole, sorbitol or glycerol, or alkoxylated glycerol or alkoxylated trimethylolpropane;

[0093] - a hydrogenated bisphenol A, F or A / F liquid resin, or the glycidylation products of hydrogenated bisphenol A, F or A / F;

[0094] - an N-glycidyl derivative of amides or heterocyclic nitrogenous bases, such as triglycidyl cyanurate or triglycidyl isocyanurate, or reaction products of epichlorohydrin with hydantoin.

[0095] - Epoxy resins produced by the oxidation of olefins, such as vinylcyclohexene, dicyclopentadiene, cyclohexadiene, cyclododecadiene, cyclododecatriene, isoprene, 1,5-hexadiene, butadiene, polybutadiene, or divinylbenzene. Other suitable epoxy resins are those produced by reacting bio-based hydroxy-functional raw materials with epichlorohydrin, especially vanillin-based epoxy resins such as diglycidyl ethers of vanillin alcohol, or glycerol-based epoxy resins.

[0096] Preferably, the epoxy resin is a liquid resin or a mixture containing two or more liquid epoxy resins.

[0097] The term "epoxy liquid resin" refers to a technical polyepoxide with a glass transition temperature below 25°C.

[0098] If necessary, additional amounts of epoxy resin may be used.

[0099] Preferred epoxy resins are aromatic liquid epoxy resins, in particular bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, or phenol-formaldehyde novolac glycidyl ether, or mixtures thereof, especially a mixture of bisphenol A diglycidyl ether and bisphenol F diglycidyl ether. Such epoxy resins are highly reactive, hydrophobic, and exhibit a low viscosity for epoxy resins. They offer good processability, rapid curing, and high adhesive strength. Aromatic liquid epoxy resins with an average epoxy equivalent weight of 150 to 250 g / eq are preferred.

[0100] In addition to the epoxy resin, at least one epoxy group-containing reactive diluent may be included.

[0101] Suitable for this purpose are, in particular, 1,4-butanediol diglycidyl ethers, 1,6-hexanediol diglycidyl ethers, trimethylolpropane di- or triglycidyl ethers, phenylglycidyl ethers, cresyl glycidyl ethers, guaiacol glycidyl ethers, 4-methoxyphenyl glycidyl ethers, pn-butylphenyl glycidyl ethers, p-tert-butylphenyl glycidyl ethers, 4-nonylphenyl glycidyl ethers, 4-dodecylphenyl glycidyl ethers, cardanol glycidyl ethers, benzyl glycidyl ethers, allyl glycidyl ethers, butyl glycidyl ethers, hexyl glycidyl ethers, 2-ethylhexyl glycidyl ethers, or glycidyl ethers of natural alcohols such as, in particular, Cs to C10 or C2 to C14 or C13 to Cis alkylglycidyl ethers.

[0102] Preferred reactive diluents include 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether or p-tert-butylphenyl glycidyl ether.

[0103] The hardener for epoxy resins contains the mercapto-functional adduct according to the invention. Additionally, the hardener preferably contains at least one polyamine with at least three hydrogen amines. Such a hardener enables the production of flexible or impact-modified epoxy resin products of very high strength.

[0104] Suitable polyamines with at least three hydrogen amines are commercially available polyamines with aliphatic amine groups, such as those commonly used for curing epoxy resins, including in particular 1,5-diamino-2-methylpentane (MPMD), 1,6-hexanediamine, 2,2(4),4-trimethyl-1,6-hexanediamine (TMD), 2-butyl-2-ethyl-1,5-pentanediamine (C11-neodiamine), isophoronediamine (IPDA), 1,3-bis(aminomethyl)benzene (MXDA), 1,4-bis(aminomethyl)benzene, 2,5-bis(aminomethyl)furan, 2,5-bis(aminomethyl)tetrahydrofuran, 1,3-bis(aminomethyl)cyclohexane (BAC), and 1,4-bis(aminomethyl)cyclohexane. Bis(4-aminocyclohexyl)methane, 1,2-diaminocyclohexane (DACH), 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 2(4)-methyl-1,3-diaminocyclohexane (MCDA), 2,5(2,6)-bis(aminome- thyl)bicyclo[2.2.1]heptane (NBDA), N-benzyl-1,2-ethanediamine, N-furfuryl-1,2-ethanediamine, N-tetrahydrofurfuryl-1,2-ethanediamine, diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA),Dipropylene triamine (DPTA), N-(2-aminoethyl)-1,3-propanediamine (N3-amine), N,N'-bis(3-aminopropyl)1,2-ethanediamine (N4-amine), bis(1,6-hexylene)triamine (BHMT), N-3-benzylaminopropyl-N'-3-aminopropyl-1,2-ethanediamine,, 3-(3-(Dimethylamino)propylamino)propylamine (DMAPAPA), polyetheramines such as bis(2-aminoethyl)ether, 3,6-dioxaoctane-1,8-diamine, 4,7-dioxadecane-1,10-diamine, 4,7-dioxadecane-2,9-diamine, 4,9-dioxadodecane-1,12-diamine, 5,8-dioxadodecane-3,10-diamine, 4,7,10-Trioxatridecan-1,13-diamine or the poly(oxy-1,2-propylene)di- or -triamines available from Huntsman as Jeffamine® D-230, D-400 or T-403, as well as corresponding types from BASF or Nitroil, phenalkamines or -amides, which are reaction products of cardanol with aldehydes, especially formaldehyde, and polyamines, amine-functional adducts of the aforementioned amines with epoxides, as well as a combination of two or more of these amines.

[0105] Preferred compounds include IPDA, MXDA, BAC, N-benzyl-1,2-ethanediamine, N-3-benzyl-aminopropyl-N'-3-aminopropyl-1,2-ethanediamine, polyetheramines, phenalkamines, or an amine-functional adduct of N-benzyl-1,2-ethanediamine with an epoxy resin, in particular a bisphenol A diglycidly ether. The epoxy resin composition may contain further components, in particular

[0106] - other amines, in particular amines with two hydrogen amines such as N,N'-dibenzyl-1,2-ethanediamine, monoamines such as benzylamine or furfurylamine, polyamidoamines such as reaction products of dimer fatty acids with DETA, TETA or TEPA, Mannich bases or aromatic polyamines such as 4(2),4'-diaminodiphenylmethane or 2,4(6)-toluenediamine,

[0107] - compounds containing other mercapto groups, in particular dimercaptans, mercaptan-terminated polysulfide polymers, mercaptan-terminated polyoxyalkylene ethers or polyesters of thiocarboxylic acids,

[0108] - further impact modifiers with epoxy groups or amine groups, such as in particular amine-functional butadienes or reaction products of hydrophobic polyols or isocyanate-containing polymers with epoxy resins, or impact modifiers in the form of isocyanate-containing polymers with blocked isocyanate groups, in particular with cardanol-blocked isocyanate groups,

[0109] - other reactive diluents, in particular epoxidized soybean oil or linseed oil, compounds containing acetoacetate groups, butyrolactone, carbonates, aldehydes, isocyanates or silicones containing reactive groups,

[0110] - Accelerators for curing, in particular phenols, phenol resins or Mannich bases such as especially 2,4,6-tris(dimethylaminomethyl)phenol, organic carboxylic acids such as salicylic acid or 2-nitrobenzoic acid, organic sulfonic acids such as methanesulfonic acid, p-toluenesulfonic acid or 4-dodecylbenzenesulfonic acid, nitrates such as especially calcium nitrate, tertiary amines, imidazoles, ammonium salts, amidines or guanidines,

[0111] - Fillers, in particular ground or precipitated calcium carbonate, optionally coated with fatty acids, in particular stearates, barite, talc, quartz flour, quartz sand, silicon carbide, micaceous iron oxide, dolomite, wollastonite, kaolin, mica (potassium aluminum silicate), molecular sieves, aluminum oxide, zinc oxide, aluminum hydroxide, magnesium hydroxide, silica, pyrogenic silica, cement, gypsum, fly ash, carbon black, graphite, ground fillers from agricultural sources such as in particular olive kernel flour or nutshell flour, hollow spheres, in particular glass spheres, metal powders such as aluminum, copper, iron, zinc, silver or steel, or PVC powder, - Pigments, such as in particular titanium dioxides, iron oxides, chromium(III) oxides, organic pigments, carbon black or corrosion protection pigments such as in particular phosphates, orthophosphates or polyphosphates, which contain as a counterion in particular chromium, zinc, aluminum, calcium, strontium or a combination of these metals,

[0112] - surface-active additives, in particular defoamers, deaerators, wetting agents, dispersants, leveling agents or dispersed paraffin waxes,

[0113] - Solvents or thinners, such as in particular benzyl alcohol, styrenized phenol, 2-phenoxyethanol, 2-benzyloxyethanol, aromatic hydrocarbon resins containing phenol groups, diisopropylnaphthalene, isopropyl biphenyls, cardanol or phenol-formaldehyde novolacs,

[0114] - Polymers, in particular polyamides, polysulfides, polyvinyl formal (PVF), polyvinyl butyral (PVB), polyurethanes (PUR), polymers with carboxyl groups, polyamides, butadiene-acrylonitrile copolymers, styrene-acrylonitrile copolymers, butadiene-styrene copolymers, homo- or copolymers of unsaturated monomers, in particular from the group comprising ethylene, propylene, butylene, isobutylene, isoprene, vinyl acetate or alkyl (meth)acrylates, in particular chlorosulfonated polyethylenes or fluorine-containing polymers or sulfonamide-modified melamines,

[0115] - Fibers, especially glass fibers, carbon fibers, metal fibers, ceramic fibers or plastic fibers such as polyamide fibers or polyethylene fibers,

[0116] - Nanofillers, especially carbon nanotubes,

[0117] - Rheology modifiers, especially thickeners or anti-settling agents,

[0118] - Adhesion improvers, especially organoalkoxysilanes,

[0119] - Flame-retardant substances, in particular the fillers already mentioned: aluminum hydroxide or magnesium hydroxide, antimony trioxide, antimony pentoxide, boric acid (B(OH)s), zinc borate, zinc phosphate, melamine borate, melamine cyanurate, ammonium polyphosphate, melamine phosphate, melamine pyrophosphate, polybrominated diphenyl oxides or diphenyl ethers, phosphates such as, in particular, diphenylcresyl phosphate, resorcinol bis(diphenyl phosphate), resorcinol diphosphate oligomer, tetraphenylresorcinol diphosphite, ethylenediamine diphosphate, bisphenol A bis(diphenyl phosphate), Tris(chloroethyl) phosphate, Tris(chloropropyl) phosphate,

[0120] Tris(dichloroisopropyl)phosphate, Tris[3-bromo-2,2-bis(bromomethyl)propyl]phosphate, Tetrabromobisphenol-A, Bis(2,3-dibromopropyl ether) of bisphenol A, brominated epoxy resins, ethylene bis(tetrabromophthalimide), ethylene bis(dibromonorbornane dicarboximide), 1,2-bis(tribromophenoxy)ethane, Tris(2,3-dibromopropyl)isocyanurate, Tribromophenol, Hexabromocyclododecane, Bis(hexachlorocyclopentadieno)cyclooctane or chlorinated paraffins, or

[0121] - Stabilisers against oxidation, heat, light or UV radiation or biocides.

[0122] Preferably, the epoxy resin composition contains less than 5 wt%, in particular less than 1 wt%, organic solvents with a boiling point at normal pressure of less than 250 °C based on the total epoxy resin composition.

[0123] Preferably, the epoxy resin composition contains less than 5% by weight of water based on the total epoxy resin composition.

[0124] Preferably, the molar ratio of the sum of hydrogen amines and mercapto groups to the epoxy groups in the epoxy resin composition is in the range of 0.5 to 1.5, in particular 0.8 to 1.2.

[0125] Preferably, the mercapto-functional adduct according to the invention is present in the epoxy resin composition in such an amount that the weight ratio between the mercapto-functional adduct and epoxy resins is in the range of 5 / 95 to 70 / 30, preferably 7 / 93 to 50 / 50, and particularly 10 / 90 to 35 / 65. Such an epoxy resin composition has high hardness, high strength, and good impact strength.

[0126] Preferably, the epoxy resin composition comprises a resin component and a hardener component, each of which is independently stable and stored in separate containers. To use the epoxy resin composition, the resin and hardener components are mixed together shortly before or during application, at which point the curing process begins.

[0127] The resin component comprises at least one epoxy resin, optionally at least one epoxy-group-containing reactive diluent, and optionally further components reactive with hydrogen amines or mercapto groups. The hardener component comprises the mercapto-functional adduct according to the invention and optionally further components reactive with epoxy groups, such as, in particular, at least one polyamine with at least three hydrogen amines. Further components of the epoxy resin composition, such as, in particular, fillers, pigments, accelerators, or surfactant additives, can be present as components of the resin component or the hardener component, or as components of both.

[0128] The resin and hardener components of the epoxy resin composition are stored in separate containers.

[0129] Suitable containers for storing the resin or hardener components include, in particular, a drum, a pail, a bag, a bucket, a can, a cartridge, or a tube. The components are storable, meaning they can be stored for several months up to a year or longer before use without their respective properties changing to an extent relevant to their application.

[0130] The resin and hardener components are mixed shortly before or during application. The mixing ratio is preferably chosen such that the molar ratio of the epoxy-reactive groups to the epoxy groups is in the range of 0.5 to 1.5, particularly 0.8 to 1.2. In parts by weight, the mixing ratio between the resin and hardener components is typically in the range of 1:2 to 20:1.

[0131] The components are mixed using a suitable method, in particular a static mixer or a dynamic mixer. Mixing can be continuous or batch-wise.

[0132] Mixing and application can take place at ambient temperature, which is typically in the range of 5 to 45 °C, preferably 10 to 35 °C.

[0133] If the components are mixed before application, care must be taken to ensure that not too much time elapses between mixing the components and the application, and that the application takes place within the pot life.

[0134] The curing of the epoxy resin composition begins with the mixing of the ingredients or components through a chemical reaction. The mercapto groups of the adduct according to the invention, the hydrogen amines of any amines present, and any other groups reactive towards epoxy groups react with the epoxy groups, causing their rings to open. As a result primarily of these reactions, the composition polymerizes and thus cures.

[0135] The curing process typically extends over several hours to several days. The duration depends, among other things, on the temperature, the reactivity of the components, their stoichiometry, and any accelerators used.

[0136] The curing can take place at ambient conditions, in particular at 5 to 45 °C, preferably at 10 to 35 °C, or it can be accelerated and / or completed by heating, in particular by heating to a temperature of 50 to 130 °C, preferably 70 to 120 °C, preferably for 5 minutes to 24 hours, particularly for 30 minutes to 4 hours.

[0137] The epoxy resin composition is preferably applied to at least one substrate.

[0138] Suitable substrates include, in particular,

[0139] - Glass, glass ceramics, concrete, mortar, cement screed, fiber cement, brick, tile, gypsum or natural stones such as granite or marble;

[0140] - Repair or leveling compounds based on PCC (polymer-modified cement mortar) or ECO (epoxy resin-modified cement mortar);

[0141] - Metals or alloys such as aluminium, iron, steel, copper, other non-ferrous metals, including surface-treated metals or alloys such as galvanised or chromium-plated metals;

[0142] - Asphalt or bitumen;

[0143] - Leather, textiles, paper, wood, with resins, for example phenolic, melamine or epoxy resins, bonded wood-based materials, resin-textile composites or other so-called polymer composites;

[0144] - Plastics such as rigid and flexible PVC, polycarbonate, polystyrene, polyester, polyamide, PMMA, ABS, SAN, epoxy resins, phenolic resins, PUR, POM, TPO, PE, PP, EPM or EPDM, either untreated or surface-treated, for example by means of plasma, corona or flames;

[0145] - Fiber-reinforced plastics, such as carbon fiber-reinforced plastics (CFRP), glass fiber-reinforced plastics (GFRP), natural fiber-reinforced plastics (NFRP) and sheet molding compounds (SMC); - Insulating materials, in particular foams, especially made of EPS, XPS, PUR, PIR, aerogel or foamed glass (foamglas), or fibers made of rock wool or glass wool,

[0146] - coated or painted substrates, in particular painted tiles, painted concrete, powder-coated metals or alloys or painted sheets;

[0147] - Coatings, paints or varnishes.

[0148] The substrates can be pretreated before application if necessary, in particular by physical and / or chemical cleaning processes or by applying an activator or a primer.

[0149] Two identical or two different substrates can be bonded and / or sealed.

[0150] The application and curing process yields the hardened epoxy resin composition. This is characterized by high hardness and high strength, combined with high impact resistance or high flexibility.

[0151] The epoxy resin composition is suitable for a wide variety of uses. It is particularly suitable as an adhesive, casting resin, coating, or filler.

[0152] The epoxy resin composition is particularly suitable as an adhesive.

[0153] Such an epoxy resin adhesive is particularly suitable for bonding applications where high strength and high impact resistance or crash resistance are required.

[0154] The epoxy resin adhesive preferably has a paste-like consistency.

[0155] Preferably, the adhesive can be applied from a dual cartridge with separate chambers for the resin and hardener components using an attached static mixer. It is advantageous if the adhesive has a low viscosity. Furthermore, such an adhesive preferably has a mixing ratio by volume of 1:1 between the resin and hardener components. Such an adhesive is particularly easy to process using a dual cartridge and attached static mixer.

[0156] The adduct according to the invention enables epoxy resin compositions, in particular epoxy resin adhesives, with very good processability, fast curing, good adhesion properties and a surprising combination of high final strength and high impact strength or flexibility.

[0157] Examples

[0158] The following are exemplary embodiments intended to further illustrate the described invention. Of course, the invention is not limited to these described embodiments.

[0159] A temperature of 23±1 °C and a relative humidity of 50±5% are referred to as "standard climate" ("NC").

[0160] Unless otherwise stated, the chemicals used were from Sigma-Aldrich Chemie GmbH.

[0161] Description of the measurement methods:

[0162] Viscosity was measured on a thermostatically controlled cone-plate viscometer Rheotec RC30 (cone diameter 10 mm, cone angle 1°, cone tip-plate distance 0.05 mm, shear rate 10 s'). 1 ) measured.

[0163] Infrared spectra (FT-IR) were measured as undiluted films on a Thermo Scientific Nicolet iS5 FT-IR instrument equipped with a horizontal ATR measuring unit with a diamond crystal. The absorption bands are given in wavenumbers (cm⁻¹). -1 ).

[0164] The content of monomeric diisocyanate was determined by HPLC (detection via photodiode array; 0.04 M sodium acetate / acetonitrile as mobile phase) after prior derivation using N-propyl-4-nitrobencylamine.

[0165] Substances used and abbreviations:

[0166] TMPMP: 1,1,1-Trimethylolpropane tris(3-mercaptopropionate) technical grade, 138 g / eq SH (Thiocure® TMPMP, from Bruno Bock GmbH)

[0167] GDMP: Ethylene glycol di(3-mercaptopropionate) technical grade, 123.5 g / eq SH (Thiocure® GDMP, from Bruno Bock GmbH)

[0168] DMDO: 1,8-dimercapto-3,6-dioxaoctane, 182.3 g / mol, 91.1 g / eq SH

[0169] BADGE: Bisphenol A diglycidyl ether (Araldite® GY-250, EEW 188 g / eq, from Huntsman)

[0170] K54: 2,4,6-Tris(dimethylaminomethyl)phenol (Ancamine® K54, from Evonik)

[0171] MXDA: 1,3-Bis(aminomethyl)benzene, AHEW 34 g / eq (from Mitsubishi Gas Chem.) Production of isocvanate group-containing polymers:

[0172] Polymer P1 :

[0173] 600 g of polyoxypropylenediol (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 according to a known procedure to form a reaction mixture with an NCO content of 15.6 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), yielding a polymer with a viscosity at 20 °C of 10.7 Pa s, an NCO content of 5.0 wt%, and a monomeric isophorone diisocyanate content of 0.03 wt%.

[0174] Polymer P2:

[0175] 600 g of polyoxypropylenediol (Voranol® 1010 L, OH number 112 mg KOH / g, from Dow) and 266.6 g of isophorone diisocyanate (Vestanat® IPDI, from Evonik) were reacted at 80 °C according to a known procedure to form a reaction mixture with a viscosity at 20 °C of 26.5 Pa s and an NCO content of 5.1 wt%.

[0176] Polymer P3:

[0177] 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 procedure 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), yielding a polymer with a viscosity at 20 °C of 16.4 Pa s, an NCO content of 1.8 wt%, and a monomeric isophorone diisocyanate content of 0.02 wt%.

[0178] Polymer P4:

[0179] 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 procedure 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), yielding a polymer with a viscosity at 20 °C of 25.1 Pa s, an NCO content of 1.6 wt% and a content of monomeric 4,4'-diphenylmethane diisocyanate of 0.04 wt%.

[0180] Production of mercapto-functional adducts:

[0181] Adducts S1 to S3 and R1 to R2:

[0182] The amount (in grams) of the specified polymercaptan given in Table 1 was reacted in the presence of 2 drops of triethylamine at room temperature, excluding moisture, with the specified amount (in grams) of the specified isocyanate-containing polymer until no more isocyanate groups could be detected by IR spectroscopy.

[0183] The properties of the adducts are given in Table 1. Adducts R1 and R2, designated '(Ref.)', serve as comparative examples. They are each prepared with a dimercaptan.

[0184]

[0185] Table 1: Mercapto-functional adducts S1 to S3 and R1 to R2.

[0186] 1 Ratio of the number of mercapto groups to the number of isocyanate groups

[0187] 2 Ratio of the number of mercaptan molecules to the number of isocyanate groups

[0188] 3 calculated

[0189] Use in epoxy resin compositions:

[0190] Compositions Z1 to Z4:

[0191] For each composition, the amount of bisphenol A diglycidyl ether (in parts by weight) specified in Table 2 was used as the resin component. Furthermore, the ingredients of the hardener component listed in Table 2 were mixed in the specified amounts (in parts by weight) and stored in a dry place.

[0192] Subsequently, the two components of each composition were processed into a homogeneous liquid using a centrifugal mixer and immediately tested as follows:

[0193] The gelling time was determined by stirring a freshly mixed quantity of approximately 3 g at regular intervals with a spatula under standard climate conditions until the mixture gelled.

[0194] To determine the mechanical properties, the mixed composition was applied to a silicone-coated release paper to form a film 2 mm thick, this was stored for 7 days under standard climate conditions, some dumbbell-shaped test specimens (length 75 mm, web length 30 mm, web width 4 mm) were punched out of the film and these were tested according to DIN EN 53504 at a tensile speed of 200 mm / min for tensile strength, elongation at break and modulus of elasticity 5% (at 0.5-5%).

[0195] Furthermore, some test specimens were punched out to determine the tear strength and tested according to DIN ISO 34-1 , method B (angled test specimen) at a tensile speed of 500 mm / min.

[0196] The Shore A hardness was determined according to DIN 53505 on test specimens cured for 7 days under standard climate conditions. These results are marked with the suffix "7d NK". To determine heat and hydrolysis stability, further Shore A test specimens were cured for 7 days under standard climate conditions and then either stored for an additional 7 days at 70 °C and 100% relative humidity, or stored for an additional 7 days in a convection oven at 100 °C. After cooling to room temperature, the Shore A hardness was determined in each case as described above. These results are marked with the suffix "+7d 70 / 100" and "+7d 100°C", respectively.

[0197] The results are given in Table 2. The compositions marked "(Ref.)" are comparative examples.

[0198]

[0199] Table 2: Composition and properties of Z1 to Z4.

[0200] Compositions Z5 to Z7: For each composition, the amount of bisphenol A diglycidyl ether (in parts by weight) specified in Table 3 was used as the resin component. Furthermore, the ingredients of the hardener component listed in Table 3 were mixed in the specified amounts (in parts by weight) and stored in a dry place.

[0201] Subsequently, the two components of each composition were processed into a homogeneous liquid using a centrifugal mixer and immediately tested as follows:

[0202] The gel time was tested as specified for composition Z1. The mechanical properties were determined by curing the mixed composition in a silicone mold for 24 hours under standard climate conditions, followed by 24 hours at 80 °C, and then for 3 days under standard climate conditions, to form dumbbell-shaped test specimens (thickness 2 mm, length 75 mm, web length 30 mm, web width 4 mm). The cured test specimens were removed from the mold, and the tensile strength, elongation at break, and modulus of elasticity (1% at 0.5 to 0.1% elongation) were measured according to EN ISO 527 at a tensile speed of 10 mm / min.

[0203] The Shore D hardness was determined according to DIN 53505 on cylindrical test specimens (diameter 20 mm, thickness 5 mm), whereby the hardness was measured after 1 day (24h) and after 2 days of storage in standard climate.

[0204] The results are shown in Table 3.

[0205] The compounds marked with "(Ref.)" are comparative examples.

[0206] Table 3: Composition and properties of Z5 to Z7.

[0207] "nb" stands for "not determined"

[0208] Table 3 shows that the composition Z5 according to the invention exhibited a high elongation at break of 13% with high tensile strength and a high modulus of elasticity. The comparative composition Z6, while exhibiting very high elongation, had undesirably low hardness (Shore D) and a low modulus of elasticity. The comparative composition Z7, with a lower content of adduct R1, did exhibit a high modulus of elasticity, but its elongation at break was significantly lower than that of Z5. Compositions Z8 to Z9: (epoxy resin adhesives)

[0209] A resin component was prepared by mixing the following ingredients in the specified amounts (in parts by weight, wt) and storing them under exclusion of moisture: 40 wt bisphenol A diglycidyl ether (Epikote® 828 LVEL, from Westlake Epoxy), 16 wt bisphenol F diglycidyl ether (Epikote® 862, from Westlake Epoxy), 6 wt butanediol diglycidyl ether (Araldite® DY-D, from Huntsman), 20 wt reaction product U1, prepared as described below, 1 wt 3-glycidoxypropyltrimethoxysilane, 12 wt fillers, and 5 wt pyrogenic silica.

[0210] The reaction product U1 was prepared by reacting 5687 g of polyetherdiol (Acclaim® 4200, OH number 28 mg KOH / g, from Covestro) and 712 g of 4,4'-diphenylmethane diisocyanate (Desmodur® 44 MC L, from Covestro) at 80 °C until a constant NCO content of 1.9 wt.% was reached, followed by reaction with Cardanol (Cardolite® NC-700, from Cardolite) for 2 h at 80 °C until no isocyanate groups were detectable by FT-IR.

[0211] Furthermore, one hardener component each was prepared by mixing the following ingredients in the specified amounts (in parts by weight, wt) and storing them under exclusion of moisture: 14 wt modified polyamine (Ancamine® 2712M, AHEW 95 g / eq, from Evonik), 6 wt polyetheramine (Jeffamine® D-230, AHEW 60 g / eq, from Huntsman), 6 wt phenalkamine (Cardolite® LITE 2002, AHEW 104 g / eq, from Cardolite), 5 wt 2,4,6-tris(dimethylaminomethyl)phenol (Ancamine® K54, from Evonik), 44 wt fillers, 6 wt pigments, 4 wt pyrogenic silica, and 15 wt of the adduct or a commercial amine-functional butadiene-acrylonitrile copolymer (Hypro® 1300X16) listed in Table 4. ATBN, AHEW 900 g / eq, from Huntsman), is listed as "ATBN" in Table 4.

[0212] The two components of each composition were then mixed to form a homogeneous liquid using a centrifugal mixer in the mixing ratio specified in Table 4. This liquid was then immediately tested as follows: As a measure of the curing rate, the tensile shear strength on steel was determined by applying the adhesive between two steel plates on a bonding surface of 12.5 x 25 mm with an adhesive thickness of 0.3 mm. After a curing time of 5 hours under standard climatic conditions, the tensile shear strength was determined according to DIN EN 1465 at a tensile rate of 10 mm / min. The mechanical properties tensile strength, elongation at break, and modulus of elasticity were determined as described for composition Z5, with curing taking place over 7 days under standard climatic conditions, a layer thickness of 1 mm on the test specimens, a tensile rate of 2 mm / min, and a modulus of elasticity of 0.25% (at 0.05 to 0.25% elongation).

[0213] The dynamic resistance was determined in an impact peel test according to ISO 11343 as a measure of impact toughness. For this test, specimens were produced with two bonded, electrolytically zinc-plated DC04 steel plates measuring 90 x 20 x 0.8 mm, with a bonding area of ​​20 x 30 mm and an adhesive thickness of 0.3 mm. These plates were cured for 7 days under standard climatic conditions. The impact peel resistance was measured at an impact velocity of 2 m / s.

[0214] The results are shown in Table 4.

[0215] The composition Z9, marked "(Ref.)", is a comparative example.

[0216]

[0217] Table 4: Composition and properties of Z8 to Z9.

[0218] 1 Resin component / hardener component (weight)

[0219] Table 4 shows that the adhesive according to the invention, composition Z8, exhibited good processability (low viscosity of the hardener component), very rapid curing and good adhesion (tensile shear strength of more than 3 MPa after only 5 hours under standard climatic conditions), high strength (tensile strength and modulus of elasticity), and very high impact strength (impact peel). In comparison, the reference composition Z9 (Ref.) with a commercially available amine-functional ATBN showed higher viscosity and slower curing with slightly lower strength and similar impact strength.

[0220] Use in compositions containing aldehyde groups:

[0221] Compositions Z10 to Z11:

[0222] For each composition, the ingredients of the first component K1, listed in Table 5, were mixed in the specified quantities (in parts by weight) using a centrifugal mixer and stored in a sealed container. Similarly, the ingredients of the second component K2, listed in Table 4, were processed and stored. Subsequently, the two components of each composition were blended into a homogeneous liquid using the centrifugal mixer and immediately tested as follows:

[0223] Gel time, tensile strength, elongation at break, modulus of elasticity 5% and Shore A were tested as described for composition Z1.

[0224] The tensile shear strength on glass was determined as a measure of the bond strength. For this purpose, composite specimens were produced by bonding two glass plates, degreased with isopropanol and pretreated with Sika® Aktivator-205 (from Sika Switzerland), such that the overlapping adhesive joint had dimensions of 12 x 25 mm and a thickness of 4 mm, with the glass plates protruding at the ends. After storage of the composite specimens for 7 days under standard climatic conditions, the tensile shear strength was tested according to DIN EN 1465 at a tensile rate of 20 mm / min. Subsequently, the fracture pattern was assessed, where "CF" stands for cohesive failure covering 90 to 100% of the fracture surface. The results are given in Table 5.

[0225]

[0226] Table 5: Composition and properties of Z10 to Z11.

[0227] 1Aldehyde equivalent weight 2400 g / eq, from the reaction of 500 g of polymer P3 with 27.7 g of 5-hydroxymethylfurfural in the presence of 0.1 g of dibutyltin dilaurate at 110 °C, until no isocyanate groups were detectable by IR spectroscopy

[0228] 2 Martinal® OL-104 (from Martinswerk)

[0229] 3 Monarch® 570 (by Cabot)

Claims

Patent claims:

1. Mercapto-functional adduct from the implementation of - at least one mercaptan M with at least three mercapto groups, with - at least one isocyanate-containing polymer with an average molecular weight M n of at least 1,000 g / mol, in a ratio of the number of mercapto groups to the number of isocyanate groups at the start of the reaction of at least 4.

2. Adduct according to claim 1, characterized in that the ratio of the number of mercapto groups to the number of isocyanate groups at the beginning of the reaction is in the range of 4 to 30, preferably 4.5 to 20, more preferably 5 to 10, in particular 6 to 9.

3. Adduct according to one of claims 1 or 2, characterized in that the mercaptan M has three or four, in particular three, mercapto groups.

4. Adduct according to any one of claims 1 to 3, characterized in that the mercaptan M has a mercapto equivalent weight of 45 to 400 g / eq, preferably 100 to 300 g / eq, wherein the mercaptan M is in particular selected from the list consisting of glycerol tris(2-mercaptoacetate), glycerol tris(3-mercaptopropionate), glycerol tris(3-mercaptobutyrate), 1,1,1-trimethylolpropane tris(2-mercaptoacetate), 1,1,1-trimethylolpropane tris(3-mercaptopropionate), 1,1,1-trimethylolpropane tris(3-mercaptobutyrate), pentaerythritol tris(2-mercaptoacetate), pentaerythritol tris(3- mercaptopropionate), pentaerythritol tris(3-mercaptobutyrate), pentaerythritol tetrakis(2-mercaptoacetate), pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), 3-mercapto-2-hydroxypropyl ether of propoxylated pentaerythritol with a medium Mercapto equivalent weight from 180 to 400 g / eq, Tris(2-(2-mercaptoacetyloxy)ethyl)isocyanurate,Tris(2-(3-mercaptopropionyloxy)ethyl)isocyanurate and Tris(2-(3-mercaptobutanoyloxy)ethyl)isocyanurate., 5. Adduct according to any one of claims 1 to 4, characterized in that the mercaptan M is glycerol tris(3-mercaptopropionate), 1,1,1-trimethylolpropane tris(2- mercaptoacetate), 1,1,1-Trimethylolpropane-tris(2-mercaptopropionate) or 1,1,1-Trimethylolpropane-tris(3-mercaptobutyrate), in particular 1,1,1-Trimethylolpropane-tris(2-mercaptopropionate).

6. Adduct according to any one of claims 1 to 5, characterized in that the isocyanate group-containing polymer has an NCO content of 1 to 9 wt%, preferably 1.5 to 6.5 wt%.

7. Adduct according to any one of claims 1 to 6, characterized in that the isocyanate group-containing polymer is a reaction product of at least one monomeric diisocyanate with at least one polymeric polyol in a molar NCO / OH ratio of at least 1.5, preferably at least 1.

8.

8. Adduct according to claim 7, characterized in that the polymeric polyol is selected from the list consisting of polyether polyols, polyester polyols and hydrocarbon polyols.

9. Adduct according to one of claims 1 to 8, characterized in that the adduct contains, based on 100 parts by weight of reaction product of mercaptan M and isocyanate group-containing polymer, less than 5 parts by weight, preferably less than 1 part by weight, in particular less than 0.5 parts by weight, organic solvents with a boiling point at normal pressure of less than 250 °C.

10. Adduct according to any one of claims 1 to 9, characterized in that the adduct has a viscosity at 20 °C of 1 to 500 Pa s, preferably 2 to 300 Pa s, in particular 3 to 250 Pa s, measured by means of 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 .

11. Adduct according to any one of claims 1 to 10, characterized in that the adduct has a mean mercapto equivalent weight of 150 to 1,500 g / eq, preferably 200 to 1,000 g / eq.

12. Use of the adduct according to any one of claims 1 to 11 as a hardener in a hardenable composition containing reactive groups selected from Epoxy group, isocyanate group, aldehyde group, vinyl group, allyl group, acrylate group and methacrylate group.

13. Epoxy resin composition comprising at least one epoxy resin and at least one hardener for epoxy resins, comprising at least one adduct according to any one of claims 1 to 11.

14. Epoxy resin composition according to claim 13, characterized in that the hardener additionally contains at least one polyamine with at least 3 hydrogen amines.

15. Epoxy resin composition according to one of claims 13 or 14, characterized in that the weight ratio between the mercaptofunctional adduct and epoxy resins is in the range of 5 / 95 to 70 / 30, preferably 7 / 93 to 50 / 50, in particular 10 / 90 to 35 / 65.

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