Polymer having aldehyde groups

Abstract

The invention relates to a non-ionic aldehyde-functional polymer with end groups of formula (I) and an average content of aldehyde groups of 0.15 to 1.2 meq / g. The polymer is suitable for cross-linking compounds with reactive groups such as more particularly cyanoacetate groups, acetoacetate groups or malonate groups at ambient temperatures. It permits a particularly long processing time with fast curing and elastic products that have particularly high tensile strength and tear propagation resistance at high extensibility. It is therefore suitable as a component of elastic adhesives, sealants or coatings that are largely free of toxic ingredients, have low sensitivity to moisture and blistering, have particularly good processability and are particularly robust and durable.

Description

[0001] POLYMER CONTAINING ALDEHYDE GROUPS

[0002] Technical area

[0003] The invention relates to polymers containing aldehyde groups and their use for curing compounds with reactive groups such as, in particular, cyanoacetate, acetoacetate or malonate groups, as well as room temperature-curable adhesives, sealants or coatings made therefrom.

[0004] State of the art

[0005] Reactive polymer compositions that cure at room temperature and can be used as adhesives, sealants, or coatings with elastic properties are well known. Polyurethane systems, which cure through the reaction of isocyanate groups with polyols and / or moisture, forming particularly highly elastic polymers, are widely used. However, these systems are susceptible to blistering caused by excessive moisture during curing, and the polyisocyanates used are usually toxic compounds. Reactive polymer compositions based on silane-functional polymers (SMP / STP) and silicones are also widespread. During their curing, alcohols, especially methanol or ethanol, or oximes are released, which are toxic and cause VOC emissions. Furthermore, they usually contain high amounts of low-molecular-weight silanes, which are also harmful to health.Water-based polymer systems are also known, which are mostly based on acrylate or polyurethane dispersions. These cure via water evaporation and coalescence and are largely free of chemical reactive groups. However, they can only be used in relatively thin layers and only between open-pore substrates; the curing rate is highly dependent on the ambient humidity, and they exhibit high shrinkage. After curing, there is increased sensitivity to water due to the surfactants they contain, which are necessary for the production and stability of the dispersion, which can lead to reduced durability, particularly in outdoor applications. Description of the invention.

[0006] The object of the present invention is to provide a functional polymer which can be crosslinked together with compounds having suitable reactive groups and enables room temperature curable compositions with elastic properties which overcome the disadvantages of the prior art.

[0007] Surprisingly, this object is achieved with a nonionic aldehyde-functional polymer as described in claim 1. The aldehyde-functional polymer according to the invention with end groups of formula (I) is not sensitive to moisture and blistering, poses little toxicological risk, requires no hazard labeling, and can be handled without special precautions. The polymer according to the invention is particularly suitable for crosslinking compounds with reactive groups, such as, in particular, cyanoacetate groups, 1,3-ketoester groups, or malonate groups. Such a polymer system is readily processable without the need for organic solvents for dissolving or diluting components, or water for emulsifying or dispersing components.It cures surprisingly quickly and smoothly under ambient conditions, regardless of humidity, without causing emissions. The curing rate is highly controllable with common catalysts, especially non-metallic bases such as tertiary amines, amidines, or guanidines. Curing produces a non-sticky, elastic polymer with high strength and ductility and good resistance to heat and water.

[0008] The polymer according to the invention enables particularly high-quality elastic adhesives, sealants, or coatings that overcome the disadvantages of the prior art with regard to toxic ingredients, sensitivity to moisture, and stability and robustness after curing. Further aspects of the invention are the subject of further independent claims. Particularly preferred embodiments of the invention are the subject of the dependent claims. Ways of carrying out the invention

[0009] The invention relates to a non-ionic aldehyde-functional polymer having end groups of the formula (I) and an average content of aldehyde groups of 0.15 to 1.2 meq / g, preferably 0.2 to 0.75 meq / g, particularly preferably 0.2 to 0.7 meq / g, in particular 0.3 to 0.6 meq / g, where

[0010] R represents a divalent organic radical having 1 to 15 C atoms and D represents a divalent hydrocarbon radical having 4 to 15 C atoms.

[0011] "Nonionic" refers to a polymer which has a content of ionic groups of less than 0.05% by weight, in particular less than 0.01% by weight, based on the polymer, wherein the ionic groups are in particular selected from carboxylate groups, ammonium groups and sulfonate groups.

[0012] “Room temperature” is defined as a temperature of 23 °C.

[0013] A dashed line in the formulas in this document represents the bond between a substituent and the corresponding molecular residue. The term "molecular weight" refers to the molar mass (in grams per mole) of a molecule. The term "average molecular weight" refers to the number average molecular weight (M n) of a polydisperse mixture of oligomeric or polymeric molecules. It is determined by gel permeation chromatography (GPC) using polystyrene as a standard.

[0014] Substance names beginning with "poly," such as polyol, polyisocyanate, polycyanoacetate, or polyacetoacetate, refer to substances that formally contain two or more of the functional groups mentioned in their name per molecule. A substance or composition is described as "storage-stable" if it can be stored at room temperature in a suitable container for an extended period, typically for at least three months up to six months or more, without its application or use properties changing to an extent relevant to its intended use.

[0015] All industry standards and norms mentioned in this document refer to the versions valid at the time of filing the initial application. Percentages by weight (wt%) refer to the mass fraction of a component of a composition or molecule relative to the entire composition or molecule, unless otherwise specified. The terms "mass" and "weight" are used synonymously in this document.

[0016] Preferably, the aldehyde-functional polymer has an average molecular weight M n from 1,500 to 20,000 g / mol, preferably 2,500 to 15,000 g / mol, in particular 3,500 to 8,000 g / mol, measured by gel permeation chromatography (GPC) against polystyrene as standard.

[0017] Preferably, the average aldehyde functionality of the aldehyde-functional polymer is 1.8 to 4, preferably 2.0 to 3, in particular 2.2 to 3.0.

[0018] The aldehyde-functional polymer preferably contains less than 20% by weight, in particular less than 15% by weight, of oxyethylene units based on the total polymer. Such a polymer is particularly resistant to moisture.

[0019] Preferably, R in formula (I) represents a linear or branched alkylene radical, cycloalkylene radical, arylalkylene radical or aryl radical, which may also contain oxygen and / or nitrogen atoms.

[0020] In particular, the radical R is selected from the group consisting of methylene, 1,2-propanediyl, 2-methyl-1,2-propanediyl, 1,4-butanediyl, 2-oxa-1,4-butanediyl, 3-oxa-1,5-pentanediyl,

[0021]

[0022] Particularly preferred is Such polymers are derived from 5-hydroxymethylfurfural, which is available from renewable raw materials. These polymers are particularly low-viscosity and enable curable compositions with high strength, elongation, tear resistance, and resistance to heat and water.

[0023] Preferably, D in the formula (I) represents the divalent radical of 1,6-hexanediamine, 2,2(4),4-trimethyl-1,6-hexanediamine, 1-methyl-2,4(6)-diaminocyclohexane, isophoronediamine, 4,4'-diaminodicyclohexylmethane, 4(2),4'-diphenylmethanediamine or 2,4(6)-toluenediamine after removal of the two amino groups.

[0024] Particularly preferably, D represents the divalent radical of 1,6-hexanediamine or isophoronediamine after removal of the two amino groups, in particular the radical of isophoronediamine after removal of the two amino groups. Such an aldehyde-functional polymer has a particularly low viscosity.

[0025] Preferably, R in the end groups of formula (I) and in the compounds of formula (II) represents the same radical.

[0026] Preferably, the aldehyde-functional polymer has a polymer backbone containing poly(oxyalkylene) units and / or polyester units.

[0027] In particular, the aldehyde-functional polymer has a poly(oxyalkylene) backbone.

[0028] Preferred poly(oxyalkylene) is poly(oxy-1,2-propylene), a mixed poly(oxy-1,2-propylene)(oxyethylene), poly(oxy-1,3-propylene), poly(oxy-1,4-butylene), poly(oxy-1,2-butylene) or a mixed form of these poly(oxyalkylenes).

[0029] Of these, preference is given to poly(oxy-1,2-propylene), poly(oxy-1,3-propylene) or poly(oxy-1,4-butylene), in particular poly(oxy-1,2-propylene), which can contain 0 to 25% by weight, preferably 0 to 20% by weight, of poly(oxyethylene) units based on the poly(oxyalkylene) backbone, in particular at the chain ends. Aldehyde-functional polymers with such a backbone have low viscosity and are therefore particularly easy to handle and particularly hydrophobic. They enable compositions with particularly good processability, high extensibility and good water resistance. Preferred polymer backbones containing polyester units are esters of dicarboxylic acids and di- or triols, and also triglycerides, in particular esters of dimer fatty acids or derived from castor oil, derivatives of castor oil or vegetable oils.

[0030] The aldehyde-functional polymer preferably has a content of compounds of the formula (II) of less than 1% by weight, preferably less than 0.5% by weight, in particular less than 0.2% by weight, based on the polymer, where R and D have the meanings already mentioned. Such an aldehyde-functional polymer surprisingly enables a particularly long processing time with rapid curing and a particularly high tensile strength and tear propagation resistance with high extensibility, making such polymer systems particularly easy to process and particularly robust and durable.

[0031] Particularly preferably, the aldehyde-functional polymer has a poly(oxyalkylene) backbone, R represents and D stands for the remainder of

[0032] Isophorone diisocyanate after removal of the two isocyanate groups.

[0033] The aldehyde-functional polymer is preferably largely free of acid groups. It preferably has an acid group content of less than 0.1% by weight, based on the polymer. Such a polymer is particularly hydrophobic and enables cured compositions with good water resistance.

[0034] The aldehyde-functional polymer is preferably liquid at room temperature. In particular, it has a sufficiently low viscosity to be flowable even without significant heating and thus easy to convey, fill, and compound. The aldehyde-functional polymer preferably has a viscosity at 20 °C of 1 to 500 Pa s, preferably 2 to 200 Pa s, in particular 5 to 100 Pa s, measured using a cone-plate viscometer with a cone diameter of 10 mm, a cone angle of 1°, a cone tip-to-plate distance of 0.05 mm, and a shear rate of 10 s. -1 .

[0035] Preferably, the aldehyde-functional polymer is a reaction product of at least one hydroxyaldehyde of the formula HO-R-CHO with at least one polymer containing isocyanate groups.

[0036] Preferably, the reaction is carried out in an OH / NCO ratio of at least 1 at a temperature of 40 to 140 °C, preferably 60 to 120 °C, optionally in the presence of a suitable catalyst and optionally in the presence of a plasticizer.

[0037] Preferably, the aldehyde-functional polymer is free of isocyanate groups.

[0038] Particularly suitable as hydroxyaldehyde are 2-hydroxyacetaldehyde, 3-hydroxybutanal, 3-hydroxypivalaldehyde, 5-hydroxypentanal, 2-(2-hydroxyethoxy)acetaldehyde, 3-(2-hydroxyethoxy)propanal, 5-hydroxymethylfurfural, alkoxylated o-, m- or p-hydroxybenzaldehyde or alkoxylated vanillin, where "alkoxylated" preferably stands for (singly or multiply) "ethoxylated" or "propoxylated", as well as 4,4'-(2-hydroxypropane-1,3-diyl)-bis(oxy)-bis(benzaldehyde) or 4,4'-(2-hydroxypropane-1,3-diyl)-bis(oxy)-bis(3-methoxybenzaldehyde).

[0039] Preferred are 5-hydroxymethylfurfural, ethoxylated salicylaldehyde, especially 2-(2-hydroxyethoxy)benzaldehyde, or ethoxylated vanillin, especially 4-(2-hydroxyethoxy)-3-methoxybenzaldehyde. These hydroxyaldehydes are accessible by simple processes and enable low-viscosity aldehyde-functional polymers.

[0040] 5-Hydroxymethylfurfural is particularly preferred. This hydroxyaldehyde is accessible from renewable starting materials and enables particularly low-viscosity polymers. The isocyanate-containing polymer preferably has a monomeric diisocyanate content of the formula OCN-D-NCO of less than 0.5% by weight, preferably less than 0.2% by weight, in particular less than 0.1% by weight, based on the isocyanate-containing polymer. Such a polymer enables a particularly low content of compounds of formula (II).

[0041] A particularly suitable polymer containing isocyanate groups for the reaction with the hydroxyaldehyde of the formula HO-R-CHO is a reaction product of at least one monomeric diisocyanate of the formula OCN-D-NCO with at least one polymeric polyol in an NCO / OH ratio in the range from 3 / 1 to 10 / 1 and subsequent removal of the monomeric diisocyanate by means of a suitable separation process to a content of less than 0.5% by weight, preferably less than 0.2% by weight, in particular less than 0.1% by weight, based on the polymer.

[0042] The isocyanate group-containing polymer preferably has an NCO content of 0.6 to 6% by weight, particularly preferably 0.9 to 3.5% by weight, in particular 1.3 to 2.7% by weight, based on the polymer.

[0043] The isocyanate group-containing polymer preferably has an average NCO functionality of 1.8 to 4, preferably 2 to 3, in particular 2.2 to 3.0.

[0044] Particularly suitable diisocyanates of the formula OCN-D-NCO are 1,6-hexane diisocyanate (HDI), 2,2(4),4-trimethyl-1,6-hexane diisocyanate (TMDI), 1-methyl-2,4(6)-diisocyanatocyclohexane (HeTDI), isophorone diisocyanate (IPDI), 4,4'-diisocyanatodicyclohexylmethane (H12MDI), 4(2),4'-diphenylmethane diisocyanate (MDI), or 2,4(6)-toluene diisocyanate (TDI). HDI or IPDI are preferred, with IPDI being particularly preferred.

[0045] Preferred polymeric polyols are polymers with an OH number in the range of 9 to 114 mg KOH / g, preferably 12 to 57 mg KOH / g, in particular 18 to 45 mg KOH / g, and a polymer backbone containing poly(oxyalkylene) units and / or polyester units. Particular preference is given to poly(oxyalkylene) polyols, castor oil, hydroxy-functional castor oil derivatives, hydroxylated vegetable oils, or dimer- or trimer-fatty acid-based polyester polyols, or polyols with poly(oxyalkylene) and polyester units.

[0046] Poly(oxyalkylene) polyols are most preferred.

[0047] Preferred poly(oxyalkylene)polyols, also called polyetherpolyols, are in particular polymerization products of ethylene oxide or 1,2-propylene oxide or 1,2- or 2,3-butylene oxide or oxetane or tetrahydrofuran, or mixtures thereof, where these can be polymerized with the aid of a starter molecule having two or more active hydrogen atoms, in particular a starter molecule such as water, ammonia or a compound having several OH or NH groups such as, for example, 1,2-ethanediol, 1,2- or 1,3-propanediol, neopentyl glycol, diethylene glycol, triethylene glycol, the isomeric dipropylene glycols or tripropylene glycols, the isomeric butanediols, pentanediols, hexanediols, heptanediols, octanediols, nonanediols, decanediols, undecanediols, 1,3- or 1 ,4-cyclohexanedimethanol, bisphenol A, hydrogenated bisphenol A, 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, glycerol or aniline, or mixtures of the aforementioned compounds.

[0048] Particularly preferred are poly(oxy-1,2-propylene)diols, poly(oxy-1,2-propylene)triols, or so-called ethylene oxide-terminated (EO-endcapped or EO-tipped) poly(oxy-1,2-propylene)diols or triols. The latter are polyoxyethylene-polyoxypropylene mixed polyols, which are obtained in particular by further alkoxylating polyoxypropylenediols or triols after completion of the propoxylation reaction with ethylene oxide, thus ultimately exhibiting primary hydroxyl groups.

[0049] Also particularly preferred are poly(oxy-1,3-propylene)diols or poly(oxy-1,4-butylene)diols.

[0050] Polyols with a degree of unsaturation of less than 0.02 meq / g, especially less than 0.01 meq / g, are preferred. Compounds of formula (II) are formed from the reaction of the monomeric diisocyanates present in the isocyanate-containing polymer with the hydroxyaldehyde of the formula HO-R-CHO. A low content of monomeric diisocyanate in the isocyanate-containing polymer enables the advantageous low content of compounds of formula (II) of less than 1% by weight, preferably less than 0.5% by weight, especially less than 0.2% by weight, based on the polymer.

[0051] The aldehyde-functional polymer according to the invention is particularly advantageous for curing compounds with at least two aldehyde-reactive groups, resulting in cured compositions with elastic properties. The low content of compounds of formula (II) enables a particularly long processing time with rapid curing and particularly high tensile strength and tear propagation resistance with high extensibility.

[0052] A further object of the invention is thus the use of the aldehyde-functional polymer for curing at least one compound V having at least two reactive groups reactive towards aldehydes.

[0053] These reactive groups are preferably selected from cyanoacetate groups, 1,3-ketoester groups and malonate groups.

[0054] Preferably, compound V is liquid at room temperature. In particular, it has a viscosity at 20 °C of 0.1 to 100 Pa s, preferably 0.2 to 50 Pa s, in particular 0.5 to 20 Pa s, measured using a cone-plate viscometer with a cone diameter of 10 mm, a cone angle of 1°, a cone tip-to-plate distance of 0.05 mm, and a shear rate of 10 s -1 , for viscosities of less than 1 Pa s with a cone diameter of 50 mm. Such a combination enables curable compositions that are easy to process at ambient temperature and without the addition of solvents or thinners.

[0055] Compound V preferably has two to four of the reactive groups mentioned. Compound V preferably has only a low water content, in particular at most 10% by weight of water based on compound V. Such a non-aqueous compound enables cured compositions with particularly high weathering stability.

[0056] Curing preferably takes place at ambient temperature, in particular at a temperature in the range of -5 to 50°C, preferably 0 to 40°C.

[0057] Compound V particularly preferably contains at least two cyanoacetate groups. This results in cured compositions with particularly good mechanical properties, in particular with high extensibility and tear resistance.

[0058] For curing at least one compound V having cyanoacetate groups, the aldehyde-functional polymer is preferably used in an amount such that the ratio of the number of cyanoacetate groups to the number of aldehyde groups is in the range from 0.7 to 1.5, preferably 0.8 to 1.2, in particular 0.9 to 1.1. Particularly suitable compounds V with cyanoacetate groups are selected from 1,2-ethanediol bis(cyanoacetate), 1,2-propanediol bis(cyanoacetate), 1,3-propanediol bis(cyanoacetate), 1,4-butanediol bis(cyanoacetate), 1,6-hexanediol bis(cyanoacetate), 1,4-cyclohexanedimethanol bis(cyanoacetate), dipropylene glycol bis(cyanoacetate), 1,1,1-trimethylolpropane tris(cyanoacetate), glycerol tris(cyanoacetate), propoxylated 1,1,1-trimethylolpropane tris(cyanoacetate) with medium molecular weight M n from 500 to 2,000 g / mol, poly(oxy-1,2-propylene)diol bis(cyanoacetate) with medium molecular weight M nfrom 2,000 to 10,000 g / mol, poly(oxy-1,2-propylene)triol tris(cyanoacetate) with medium molecular weight M n from 2,000 to 10,000 g / mol, poly(oxy-1,2-propylene)diol bis(cyanoacetate) containing ethylene oxide units with an average molecular weight M n from 2,000 to 10,000 g / mol, poly(oxy-1,2-propylene)triol tris(cyanoacetate) containing ethylene oxide units with an average molecular weight M n from 2,000 to 10,000 g / mol, dimer fatty acid-based polyesterdiol bis(cyanoacetate) with medium molecular weight M n from 1,000 to 4,000 g / mol and trimer fatty acid-based polyester triol tris(cyanoacetate) with medium molecular weight M n from 1,000 to 4,000 g / mol. Such compounds V containing cyanoacetate groups are obtained in particular from the transesterification of at least one cyanoacetate of the formula (III)

[0059] OXC") <3R 1 , where R 1represents C1-6 alkyl, with at least one polyfunctional alcohol to release and remove the alcohol of formula R 1 -OH.

[0060] Preferably R 1 stands for methyl, ethyl or tert. butyl, in particular for ethyl.

[0061] Furthermore, the compound V preferably has at least two 1,3-ketoester groups, preferably at least two 1,3-ketoester groups of the formula (IV), in particular at least two acetoacetate groups.

[0062] Y E ”

[0063] In formula (IV) R 2 represents a monovalent hydrocarbon radical having 1 to 6 C atoms, preferably methyl, ethyl, propyl, isopropyl, butyl or phenyl, in particular methyl.

[0064] For curing at least one compound V having 1,3-ketoester groups, the aldehyde-functional polymer is preferably used in an amount such that the ratio of the number of 1,3-ketoester groups to the number of aldehyde groups is in the range from 0.5 to 2.5, particularly preferably 0.8 to 2.2, in particular 1 to 2.

[0065] Particularly suitable compounds V with 1,3-ketoester groups are selected from 1,2-ethanediol bis(acetoacetate), 1,2-propanediol bis(acetoacetate), 1,3-propanediol bis(acetoacetate), 1,4-butanediol bis(acetoacetate), 1,6-hexanediol bis(acetoacetate), 1,4-cyclohexanedimethanol bis(acetoacetate), dipropylene glycol bis(acetoacetate), 1,1,1-trimethylolpropane tris(acetoacetate), glycerol tris(acetoacetate), propoxylated 1,1,1-trimethylolpropane tris(acetoacetate) with medium molecular weight M n from 500 to 2,000 g / mol, poly(oxy-1,2-propylene)diol bis(acetoacetate) with medium molecular weight M nfrom 600 to 10,000 g / mol, poly(oxy-1,2-propylene)triol- tris(acetoacetate) with medium molecular weight M n from 2,000 to 10,000 g / mol, ethylene oxide unit-containing poly(oxy-1,2-propylene)triol-tris(acetoacetate) with an average molecular weight Mn of 2,000 to 10,000 g / mol, dimer fatty acid-based polyesterdiol-bis(acetoacetate) and trimer fatty acid-based polyestertriol-tris(acetoacetate).

[0066] Such compounds V with 1,3-ketoester groups are obtained in particular from the transesterification of at least one 1,3-ketoester of the formula (V),

[0067] OOA

[0068] R 4 O X ^ / ^R 3 (V) where R 3 for a monovalent hydrocarbon radical with 1 to 6 C atoms and R 4 are C1-6 alkyl, with at least one polyfunctional alcohol to release and remove the alcohol of formula R 4 OH.

[0069] Preference is given to R3 where R is methyl, ethyl, propyl, isopropyl, butyl or phenyl, preferably methyl or phenyl, in particular methyl, and R 4 for methyl, ethyl or tert. butyl, especially for ethyl.

[0070] Compounds V containing 1,3-ketoester groups are further obtained by reacting diketene or the adduct of diketene with acetone (= 2,2,6-trimethyl-4H-1,3-dioxin-4-one) with at least one polyfunctional alcohol, acetone being released in the case of the acetone-diketene adduct.

[0071] Furthermore, the compound V preferably has at least two malonate groups, OO in particular malonate groups of the formula

[0072] For curing at least one compound V having malonate groups, the aldehyde-functional polymer is preferably used in an amount such that the ratio of the number of malonate groups to the number of aldehyde groups is in the range from 0.5 to 2.5, particularly preferably 0.8 to 2.2, in particular 1 to 2. Particularly suitable compounds V with malonate groups are selected from 1,2-ethanediol bis(ethylmalonate), 1,2-propanediol bis(ethylmalonate), 1,3-propanediol bis(ethylmalonate), 1,4-butanediol bis(ethylmalonate), 1,6-hexanediol bis(ethylmalonate), 1,4-cyclohexanedimethanol bis(ethylmalonate), diethylene glycol bis(ethylmalonate), dipropylene glycol bis(ethylmalonate), glycerol tris(ethylmalonate), 1,1,1-trimethylolpropane tris(ethylmalonate), dimer fatty acid diol bis(ethylmalonate), trimer fatty acid triol tris(ethylmalonate), castor oil tris(ethylmalonate), poly(oxy-1 ,2-propylene)diol bis(ethylmalonate) with an average molecular weight M nfrom 500 to 2,000 g / mol, propoxylated 1,1,1-trimethylolpropane with three ethyl malonate end groups and an average molecular weight M n from 650 to 2,500 g / mol, corresponding oligomeric compounds of these reaction products and polyesterdiols containing malonate groups from the reaction of diols such as 1,6-hexanediol or 1,4-cyclohexanedimethanol with malonic acid or diethyl malonate and optionally further dicarboxylic acids or their esters, such as in particular adipic acid or diethyl adipic acid or dimer fatty acids. Suitable compounds V containing malonate groups are obtained in particular from the reaction of at least one polyfunctional alcohol with malonic acid or at least one malonate of the formula (VI), where R 5 and R 6 each represent an alkyl radical having 1 to 6 C atoms. R is preferably 5 and R 6 each represents methyl, ethyl or isopropyl, in particular ethyl.

[0073] Preferred malonates of formula (VI) are dimethyl malonate, diethyl malonate, diisopropyl malonate, butylethyl malonate, tert-butylethyl malonate, or di-tert-butyl malonate. Particular preference is given to dimethyl malonate, diethyl malonate, or diisopropyl malonate, especially diethyl malonate.

[0074] Suitable polyfunctional alcohols for the reaction with cyanoacetates of the formula (III) or 1,3-ketoesters of the formula (V) or malonates of the formula (VI) are commercially available compounds or polymers having two or more OH groups, such as in particular 1,2-ethanediol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol, dipropylene glycol, 1,1,1-trimethylolpropane, glycerol, ethoxylated or in particular propoxylated glycerol, ethoxylated or in particular propoxylated 1,1,1-trimethylolpropane, castor oil, ethoxylated or in particular propoxylated castor oil, ketone resin-modified Castor oil, poly(oxy-1,2-propylene)diols or triols, ethylene oxide endcapped poly(oxy-1,2-propylene)diols or triols, dimer fatty acid diols or trimer fatty acid triols or dimer- or trimer fatty acid-based polyester diols or triols.

[0075] Compounds V containing malonate groups are also available from the reaction of malonic acid with polyfunctional alcohols containing an excess of OH groups. The stoichiometry in the reaction is preferably in the range of 2.2 to 3.5, preferably 2.3 to 3.3, molar equivalents of OH groups of the polyfunctional alcohol per mole of malonic acid. Other dicarboxylic acids, such as adipic acid, can also be used in this reaction.

[0076] Also possible are compounds V with mixed reactive groups, for example a compound V with at least one cyanoacetate group and at least one acetoacetate group, or with at least one cyanoacetate group and at least one malonate group, or with at least one acetoacetate group and at least one malonate group.

[0077] Preferably, the aldehyde-functional polymer is used for curing at least one compound V as a component of a two-component composition, wherein the first component contains the aldehyde-functional polymer according to the invention and the second component contains the compound V, wherein the first and the second component are storage-stable on their own and are stored in separate containers until they are mixed together shortly before or during application.

[0078] The two-component composition may additionally contain further constituents, in particular fillers, fibers, nanofillers such as graphene or carbon nanotubes, dyes, pigments, plasticizers, solvents, rheology modifiers, adhesion promoters such as in particular titanates or organoalkoxysilanes, catalysts, in particular non-metallic bases such as tertiary amines, amidines or guanidines or basic salts such as in particular potassium acetate, potassium benzoate, potassium carbonate or sodium acetate, in particular as an aqueous solution, or flame-retardant substances, additives such as in particular wetting agents, flow agents, defoamers, deaerators or stabilizers against oxidation, heat, light or UV radiation, or other substances commonly used in curable compositions.

[0079] Such additives can be present as part of the first or second component. Substances reactive with aldehyde groups are preferably part of the second component.

[0080] The composition preferably additionally contains at least one further component selected from plasticizers, fillers, and catalysts. In particular, it contains several such further components.

[0081] The composition preferably contains less than 10% by weight, more preferably less than 5% by weight, and in particular less than 1% by weight, of volatile organic solvents with a boiling point at atmospheric pressure of less than 250°C, based on the total composition. Such a composition causes particularly low emissions.

[0082] The consistency of the first and second components is suitably such that the components can be easily mixed together under ambient conditions using simple methods. Liquid or pasty components are particularly suitable for this purpose.

[0083] For use, the two components and any additional components present are mixed together shortly before or during application. The mixing ratio is selected so that the ratio of the reactive groups is within a suitable range. In parts by weight, the mixing ratio between the first and second components is typically in the range of approximately 100:1 to 1:5, in particular 50:1 to 1:2.

[0084] If the components are mixed together before application, care must be taken to ensure that not too much time passes between mixing the components and application, as otherwise the onset of the reaction and the associated increase in viscosity may lead to problems such as insufficient flow or slow or incomplete adhesion to the substrate.

[0085] The processing time is the time between mixing the components and the end of the composition's processing state. A long processing time with subsequent rapid curing is particularly advantageous.

[0086] Mixing and curing preferably take place at ambient temperature.

[0087] When the two components are mixed, the composition begins to harden through the chemical reaction that begins. The aldehyde groups react primarily with the existing reactive groups of compound V, causing the composition to ultimately harden into a solid, polymeric material.

[0088] In the case of cyanoacetate groups as reactive groups of compound V, it can be assumed that the curing reaction produces structural units of the

[0089] formula be formed.

[0090] In the case of 1,3-ketoester groups as reactive groups of compound V, it can be assumed that the curing reaction produces structural units of the

[0091] formula are formed, whereby an additional 1,3-ketoester group, if present, can add to the resulting C=C double bond and thus increase the crosslinking density.

[0092] In the case of malonate groups as reactive groups of compound V, it can be assumed that the curing reaction produces structural units of the formula are formed, whereby an additional malonate group, if present, can add to the resulting C=C double bond and thus increase the crosslinking density

[0093] In particular, curing produces an elastic material with a tensile strength of at least 1 MPa, preferably at least 2 MPa, and an elongation at break of at least 50%, preferably at least 100%, particularly preferably at least 200%, in particular at least 400%, determined according to DIN EN 53504 at a tensile speed of 200 mm / min.

[0094] The aldehyde-functional polymer according to the invention with end groups of formula (I) enables a particularly long processing time with rapid curing and a particularly high tensile strength and tear propagation resistance with high extensibility, whereby such polymer systems are particularly easy to process and particularly robust and durable.

[0095] The aldehyde-functional polymer according to the invention is particularly suitable as a component of elastic adhesives, sealants or coatings which are largely free of toxic ingredients, are not very sensitive to moisture and have a high resistance and robustness after curing.

[0096] Examples

[0097] The following are exemplary embodiments intended to further illustrate the described invention. Of course, the invention is not limited to these described exemplary embodiments.

[0098] The “standard climate” (“NK”) is defined as a temperature of 23±1 °C and a relative humidity of 50±5%.

[0099] Unless otherwise stated, the chemicals used were from Sigma-Aldrich Chemie GmbH. Description of the measurement methods:

[0100] 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-nitrobenzylamine.

[0101] The viscosity was measured on a thermostatted cone-plate viscometer Rheotec RC30 (cone diameter 10 mm, cone angle 1 °, cone tip-plate distance 0.05 mm, shear rate 10 s -1 ) were measured. Viscosities of less than 1 Pa s were measured with a cone diameter of 50 mm.

[0102] Infrared spectra (FT-IR) were measured on undiluted films on a Thermo Scientific Nicolet iS5 FT-IR instrument equipped with a horizontal diamond crystal ATR measurement unit. The absorption bands are given in wavenumbers (cm -1 ) is indicated.

[0103] Production of polymers containing isocyanate groups:

[0104] Polymer NCO-1 :

[0105] 780 g of ethylene oxide-terminated polyoxypropylenetriol (Desmophen® 5031 BT, OH number 28.0 mg KOH / g, from Covestro) and 303 g of isophorone diisocyanate (Vestanat® IPDI, from Evonik) were reacted at 80 °C using a known method to form a reaction mixture with an NCO content of 9.1% by weight. The volatile components, particularly unreacted isophorone diisocyanate, were then removed by distillation in a short-path evaporator (jacket temperature 160 °C, pressure 0.1 to 0.005 mbar), yielding a polymer with an NCO content of 1.84% by weight and a monomeric isophorone diisocyanate content of 0.02% by weight.

[0106] Polymer NCO-2:

[0107] 894.5 g of ethylene oxide-terminated polyoxypropylenetriol (Desmophen® 5031 BT, OH number 28.0 mg KOH / g, from Covestro) and 102.0 g of isophorone diisocyanate (Vestanat® IPDI, from Evonik) were reacted in the presence of 0.01 g of dibutyltin dilaurate according to a known method at 80 °C to form a polymer with an NCO content of 1.83 wt.% and a monomeric isophorone diisocyanate content of 1.4 wt.%. Polymer NCO-3:

[0108] 590 g of polyoxypropylenediol (Acclaim® 4200, OH number 28 mg KOH / g, from Covestro), 1180 g of ethylene oxide-terminated polyoxypropylenetriol (Caradol® MD34-02, OH number 35 mg KOH / g, from Shell) and 230 g of isophorone diisocyanate (Vestanat® I PDI, from Evonik) were reacted at 80 °C according to a known method to form a polymer with an NCO content of 2.1% by weight and a content of monomeric isophorone diisocyanate of 1.3% by weight.

[0109] Polymer NCO-4:

[0110] 818 g of polyoxypropylene diol (Acclaim® 4200, OH number 28.5 mg KOH / g, from Covestro) and 227 g of isophorone diisocyanate (Vestanat® I PDI, from Evonik) were reacted at 80 °C using a known method to form a reaction mixture with an NCO content of 6.6% by weight. The volatile components, particularly unreacted isophorone diisocyanate, were then removed by distillation in a short-path evaporator (jacket temperature 160 °C, pressure 0.1 to 0.005 mbar), yielding a polymer with an NCO content of 1.91% by weight and a monomeric isophorone diisocyanate content of 0.03% by weight.

[0111] Polymer NCO-5:

[0112] 600 g of polyoxypropylene diol (Voranol® 1010 L, OH number 112 mg KOH / g, from Dow) and 533.3 g of isophorone diisocyanate (Vestanat® I PDI, from Evonik) were reacted at 80 °C using a known method to form a reaction mixture with an NCO content of 15.6% by weight. The volatile components, particularly unreacted isophorone diisocyanate, were then removed by distillation in a short-path evaporator (jacket temperature 160 °C, pressure 0.1 to 0.005 mbar), yielding a polymer with an NCO content of 5.18% by weight and a monomeric isophorone diisocyanate content of 0.03% by weight.

[0113] Polymer NCO-6:

[0114] 150 g of polyoxypropylene diol (Voranol® P400, OH number 263 mg KOH / g, from Dow) and 156.4 g of isophorone diisocyanate (Vestanat® I PDI, from Evonik) were reacted at 80 °C using a known method to form a reaction mixture with an NCO content of 9.65 wt.% and a monomeric isophorone diisocyanate content of > 1 wt.%. Preparation of aldehyde-functional polymers:

[0115] Polymers A-1 to A-8:

[0116] For each of the compounds, the amounts (in parts by weight) of the corresponding isocyanate group-containing polymer specified in Table 1 were reacted with the specified amount (in parts by weight) of the corresponding hydroxy-functional aldehyde in the presence of 0.02 wt% dibutyltin dilaurate under exclusion of moisture at 110 °C until no more isocyanate groups were detectable by IR spectroscopy.

[0117]

[0118] Table 1: Preparation and properties of polymers A-1 to A-8.

[0119] 1 4,4'-(2-Hydroxypropane-1,3-diyl)-bis(oxy)-bis(3-methoxybenzaldehyde), prepared from 2 mol vanillin and 1 mol epichlorohydrin

[0120] The average molecular weight M n by gel permeation chromatography (GPC) against polystyrene (474 ​​to 2,520,000 g / mol) as a standard with tetrahydrofuran as the mobile phase and a refractive index detector. The average molecular weight M n was 6,100 g / mol.

[0121] Polymer A-8, designated "(Ref.)," is a comparative example with an average aldehyde group content of 1.07 meq / g, thus outside the claimed range. It was glassy solid at room temperature and was therefore not used to produce a curable composition. Preparation of compounds with at least two reactive groups:

[0122] Compound V-1 : (with cyanoacetate groups)

[0123] 50.0 g of trimethylolpropane-initiated poly(oxy-1,2-propylene)triol (Desmophen® 4011 T, OH number 550 mg KOH / g, from Covestro) were treated with 61.0 g of ethyl cyanoacetate and 0.1 g of tetra-n-butyl titanate (Tyzor® TnBT, from Dorf Ketal) and reacted under vacuum and with distillative removal of ethanol at a temperature of 140 °C. A clear, colorless liquid with a viscosity at 20 °C of 1.72 Pa s, a cyanoacetate functionality of 3, and a calculated cyanoacetate equivalent weight of 169 g / eq was obtained.

[0124] Compound V-2: (with acetoacetate groups)

[0125] 50.0 g of trimethylolpropane-initiated poly(oxy-1,2-propylene)triol (Desmophen® 4011 T, OH number 550 mg KOH / g, from Covestro) were treated with 67.0 g of ethyl acetoacetate and 0.1 g of tetra-n-butyl titanate (Tyzor® TnBT, from Dorf Ketal) and reacted under vacuum and with distillative removal of ethanol at a temperature of 140 °C. A clear, colorless liquid with a viscosity at 20 °C of 0.8 Pa s, an acetoacetate functionality of 3, and a calculated acetoacetate equivalent weight of 186 g / eq was obtained.

[0126] Compound V-3: (with malonate groups)

[0127] 123.4 g of trimethylolpropane-initiated poly(oxy-1,2-propylene)triol (Desmophen® 4011 T, OH number 550 mg KOH / g, from Covestro) were mixed with 192.2 g of diethyl malonate and 0.3 g of tetra-n-butyl titanate (Tyzor® TnBT, from Dorf Ketal) and reacted under vacuum and with distillative removal of ethanol at a temperature of 140 °C. A clear, colorless liquid was obtained with a viscosity at 20 °C of 7.3 Pa s, an estimated malonate functionality of approximately 3, and an estimated malonate equivalent weight of approximately 217 g / eq.

[0128] Production of curable compositions:

[0129] Compositions Z-1 to Z-10

[0130] For each example, the ingredients of the first component (K1) listed in Tables 2 and 3 were mixed in the specified amounts (in parts by weight) using a centrifugal mixer (Speed ​​Mixer™ DAC 150, FlackTek Inc.) and stored in a sealed container.

[0131] Likewise, the ingredients of the second component (K2) listed in Tables 2 and 3 were processed and stored.

[0132] Socal® U1S2 (from Imerys), a precipitated and stearate-coated calcium carbonate, was used as "CaCOs precipitated".

[0133] Monarch® 570 (from Cabot) was used as the soot.

[0134] The two components of each composition were then processed into a homogeneous liquid using the centrifugal mixer and immediately tested as follows:

[0135] The setting time was determined by stirring a freshly mixed amount of approximately 3 g in standard conditions with a spatula at regular intervals until this was no longer possible due to the gelling of the mass.

[0136] To determine the mechanical properties, the mixed composition was applied to a silicone-coated release paper to form a 2 mm thick film. This film was cured for 7 days under standard climate conditions. Several dumbbell-shaped test specimens with a length of 75 mm, a web length of 30 mm and a web width of 4 mm were punched out of the film and these were tested according to DIN EN 53504 at a tensile speed of 200 mm / min for tensile strength, elongation at break, Young's modulus 5% (at 0.5-5% elongation) and Young's modulus 50% (at 0.5-50% elongation). Furthermore, some test specimens were punched out to determine the tear propagation resistance and tested according to DIN ISO 34-1, method B (angular test specimen) at a tensile speed of 500 mm / min. 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".For some compounds, the Shore A hardness was also determined after 1 day, 2 days, and 4 days of curing and designated accordingly. To determine heat and water resistance, additional Shore A test specimens for some compounds were either stored for an additional 7 days in a convection oven at 100°C or stored for an additional 7 days at 70°C and 100% relative humidity. After cooling to room temperature, the Shore A hardness was determined as described. These results are designated "+7d 100°C" or "+7d 70 / 100."

[0137] Upon curing, a non-sticky, elastic material was formed. The results are shown in Tables 2 and 3.

[0138] Table 2: Composition and properties of Z-1 to Z-3.

[0139] 1 2,2'-Bis(dimethylamino)diethyl ether

[0140] 22,2'-Dimorpholinodiethyl ether

[0141] From Table 2 it can be seen that the composition Z-1 with polymer A-1 with only 0.04 wt% compound of formula (II) has a longer processing time with rapid curing and a higher tensile strength and tear propagation resistance with high extensibility, compared to the compositions Z-2 and Z-3 with the polymers A-2 and A-3, which have a high content of compound of formula (II) with 2.8 and 2.6 wt% respectively.

[0142] Table 3: Composition and properties of Z-4 to Z-10.

[0143] "nb" stands for "not determined"

[0144] 1 2,2'-Bis(dimethylamino)diethyl ether

[0145] 2 2,2'-Dimorpholinodiethyl ether

[0146] 3 1,8-Diazabicyclo[5.4.0]undec-7-ene (Lupragen® N700, from BASF)

Claims

Patent claims: 1 . Nonionic aldehyde-functional polymer with end groups of formula (I) and an average content of aldehyde groups of 0.15 to 1.2 meq / g, preferably 0.2 to 0.75 meq / g, particularly preferably 0.2 to 0.7 meq / g, in particular 0.3 to 0.6 meq / g, where R represents a divalent organic radical having 1 to 15 C atoms and D represents a divalent hydrocarbon radical having 4 to 15 C atoms.

2. Aldehyde-functional polymer according to claim 1, characterized in that the average molecular weight M n 1,500 to 20,000 g / mol, preferably 2,500 to 15,000 g / mol, in particular 3,500 to 8,000 g / mol, measured by gel permeation chromatography (GPC) against polystyrene as standard.

3. Aldehyde-functional polymer according to one of claims 1 or 2, characterized in that the average aldehyde functionality is 1.8 to 4, preferably 2.0 to 3, in particular 2.2 to 3.

0.

4. Aldehyde-functional polymer according to one of claims 1 to 3, characterized in that R represents a linear or branched alkylene radical, cycloalkylene radical, arylalkylene radical or aryl radical, which may also contain oxygen and / or nitrogen atoms.

5. Aldehyde-functional polymer according to one of claims 1 to 4, characterized in that D is the divalent radical of 1,6-hexanediamine, 2,2(4),4-trimethyl-1,6-hexanediamine, 1-methyl-2,4(6)-diaminocyclohexane, isophoronediamine, 4,4'-diaminodicyclohexylmethane, 4(2),4'-diphenyl- methanediamine or 2,4(6)-toluenediamine after removal of the two amino groups, preferably the residue of 1,6-hexanediamine or isophoronediamine after removal of the two amino groups.

6. Aldehyde-functional polymer according to one of claims 1 to 5, characterized in that it has a polymer backbone containing poly(oxyalkylene) units and / or polyester units.

7. Aldehyde-functional polymer according to one of claims 1 to 6, characterized in that it contains compounds of formula (II) of less than 1% by weight based on the polymer.

8. Aldehyde-functional polymer according to one of claims 1 to 7, characterized in that it has a content of acid groups of less than 0.1% by weight based on the polymer.

9. Aldehyde-functional polymer according to one of claims 1 to 8, characterized in that it has a viscosity at 20 °C of 1 to 500 Pa s, preferably 2 to 200 Pa s, in particular 5 to 100 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-to-plate distance of 0.05 mm, and a shear rate of 10 s -1 .

10. Aldehyde-functional polymer according to one of claims 1 to 9, characterized in that it is a reaction product of at least one hydroxyaldehyde of the formula HO-R-CHO with at least one polymer containing isocyanate groups.

11. Aldehyde-functional polymer according to claim 10, characterized in that the isocyanate group-containing polymer is a reaction product of at least one monomeric diisocyanate of the formula OCN-D-NCO with at least one polymeric polyol in an NCO / OH ratio in the range from 3 / 1 to 10 / 1 and subsequent removal of the monomeric diisocyanate by means of a suitable separation process down to a content of less than 0.5% by weight, based on the polymer containing isocyanate groups. Aldehyde-functional polymer according to claim 11, characterized in that the polymeric polyol is a polymer with an OH number in the range from 9 to 114 mg KOH / g, preferably 12 to 57 mg KOH / g, in particular 18 to 45 mg KOH / g, and a polymer backbone containing poly(oxyalkylene) units and / or polyester units. Use of the aldehyde-functional polymer according to any one of claims 1 to 12 for curing at least one compound V having at least two reactive groups reactive towards aldehydes.Use according to claim 13, characterized in that curing takes place at ambient temperature, in particular at a temperature in the range from -5 to 50°C, preferably 0 to 40°C. Use according to one of claims 13 to 14, characterized in that upon curing, an elastic material is obtained having a tensile strength of at least 1 MPa, preferably at least 2 MPa, in particular at least 3 MPa, and an elongation at break of at least 50%, preferably at least 100%, particularly preferably at least 200%, in particular at least 400%, determined according to DIN EN 53504 at a tensile speed of 200 mm / min.

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