NCO-terminated prepolymers for coating applications

Abstract

The present invention relates to NCO-terminated prepolymers for coating applications, a method for preparing the NCO-terminated prepolymers of the present invention, and the use of the NCO-terminated prepolymers of the present invention.The present invention further relates to a two-component system comprising component A) which comprises at least the NCO-terminated prepolymers of the present invention, and component B) which comprises at least one compound which comprises at least one Zerewitinoff-active group.Furthermore, the present invention relates to a method for curing the composition on a substrate and to the cured article.

Description

[Technical field]

[0001] The present invention relates to NCO-terminated prepolymers for coating applications, to a method for preparing the NCO-terminated prepolymers of the present invention, and to the use of the NCO-terminated prepolymers of the present invention.The present invention further relates to a two-component system comprising component A) which comprises at least the NCO-terminated prepolymers of the present invention, and component B) which comprises at least one compound which comprises at least one Zerewitinoff active group.Furthermore, the present invention relates to a method for curing the composition on a substrate and to a cured article. [Background technology]

[0002] It is known that NCO-terminated prepolymers can be used as a curing component in polyurethane coatings or coating systems. These prepolymers are generally obtained by reacting a polyol with a diisocyanate or polyisocyanate. As a curing component, the prepolymer then reacts with a further polyol, such as a polyacrylate polyol, in the coating or coating system to give the corresponding polyurethane. Depending on the desired application, such as an original equipment manufacturer (OEM) coating process, or manual coating applications in the refinishing field, the requirements for the applied coating composition can vary significantly.

[0003] WO2016 / 116376A1 describes isocyanate-functional polyester prepolymers from a combination of branched polyesters and caprolactone polyesters that have stable crystallization and high elasticity at temperatures above 5°C while having low viscosity. However, these prepolymers do not produce suitable coatings when cured with standard commercially available polyols. In particular, these formulations do not dry and have limited solvent resistance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2016 / 116376 Summary of the Invention [Problem to be solved by the invention]

[0005] It was therefore an object of the present invention to provide NCO-terminated prepolymers that allow the formulation of curable compositions with standard commercially available polyols as binders while maintaining the excellent physical and chemical properties of the resulting coatings. [Means for solving the problem]

[0006] The inventors have surprisingly found that the following aspects of the invention are able to overcome the above mentioned drawbacks: The present invention relates to a compound represented by the general formula (I) [ka] wherein P, Q and p are defined as follows: P each independently represents at least one organic radical obtained by removing a hydroxyl group from a polyol unit; Q each independently represents at least one organic radical obtained by removing an isocyanate group from a monomeric diisocyanate unit and / or at least one organic radical obtained by removing an isocyanate group from a uretdione unit having two isocyanate groups; and p each independently is a number equal to or greater than 2.0, and Here, the NCO-terminated prepolymer is an NCO content of 6.5% by weight or more and 12.0% by weight or less, based on the total solids content of the NCO-terminated prepolymer; and a content of not more than 17% by weight of oligomers having a number average molecular weight of not more than 1000 g / mol, based on the total solids content of the NCO-terminated prepolymer; and a monomeric diisocyanate content of less than 0.5% by weight, based on the total solids content of the NCO-terminated prepolymer; and Polydispersity of 2.0 or greater have The present invention relates to NCO-terminated prepolymers, preferably for manual coating applications, having the formula:

[0007] In the present invention, any numerical range recited herein is intended to include all subranges subsumed therein. For example, a range of "1 to 10" is intended to include all subranges between (and including) the recited minimum value of 1 and the recited maximum value of 10, i.e., having a minimum value of 1 or more and a maximum value of 10 or less.

[0008] In the present invention, "unit" means that the structural unit present in the general formula (I) is derived from the reactive compound described below. For example, when a diisocyanate is converted with a diol or polyol, one isocyanate group and one hydroxyl group form a urethane group. However, the remaining compound used, such as the six methyl groups of hexamethylene diisocyanate, remains unchanged. Therefore, "unit" in the present invention is understood to mean both the part of the compound that does not participate in the reaction, and the functional group, such as the hydroxyl group or isocyanate group, that undergoes the reaction to form the urethane group shown in the general formula (I). In the present invention, the corresponding unit is always derived from the compound used in the synthesis.

[0009] In the present invention, "independently of each other" means that, if the corresponding unit is present more than once in the general formula (I), the units are equal or different and are selected from the group of possible units. According to the present invention, it is also possible to have a mixture of compounds of the general formula (I) and the different possible units present in the individual molecules.

[0010] The prepolymers of the present invention having the general formula (I) are NCO-terminated. In the present invention, the term "NCO-terminated" means that the functional end groups present are essentially isocyanate groups. In this regard, the term "essentially" means that preferably at least 80 mol%, more preferably at least 90 mol%, and most preferably 99 or more to 100 mol% of the functional end groups present in the NCO-terminated prepolymer are isocyanate groups, also referred to herein as NCO groups.

[0011] In the present invention, the term "polymer" refers to a compound formed during a chemical reaction by linking together several monomers (i.e. more than two monomers) of the same or different types through covalent bonds, and the resulting polymers may differ in their degree of polymerization, molecular weight distribution, and chain length. Thus, a polymer according to the present invention is a compound that comprises at least one repeating unit in its molecular structure, which is incorporated into the polymer structure during the polymer synthesis by repeatedly linking monomers through covalent bonds to form said polymer structure.

[0012] The term "polymer" includes homopolymers, copolymers, block copolymers and oligomers.

[0013] In the present invention, a "prepolymer" is a polymer having reactive groups. Similar to the definition of the term "polymer", the molecular structure of a prepolymer is formed by repeatedly linking more than two monomers of the same or different types. A prepolymer can participate in the subsequent formation of a polymer having a higher molecular weight than said prepolymer. The term "prepolymer" encompasses a polymer that can react chemically through at least one of its reactive groups to form a repeat unit of a (preferably crosslinked) polymer. Thus, the term "prepolymer" also encompasses self-crosslinking polymers having at least two different types of reactive groups, said groups being capable of chemically reacting between themselves so that the prepolymer molecules can be crosslinked. The number average molecular weight is preferably at least 900 g / mol, more preferably at least 1,000 g / mol.

[0014] According to the present invention, unless otherwise specified, the average molecular weight is defined as the number average molecular weight Mn. As the molecular weight of the polymer, the number average molecular weight Mn is applied. Mn is determined by gel permeation chromatography (GPC) in tetrahydrofuran as solvent at 23°C. The measurement is carried out as described in DIN 55672-1:2016-03 "Gelpermeationschromatographie, Teil 1-Tetrahydrofuran als Elutionsmittel".

[0015] According to the present invention, the content of oligomers with a number average molecular weight of 1000 g / mol or less is determined using the GPC method described above. The percentage is obtained from the area % chromatogram, which is determined with software support and is approximately equal to the weight % percentage.

[0016] The content of monomeric diisocyanates, determined by gas chromatography using an internal standard in accordance with DIN EN ISO 10283:2007-11, is preferably less than 0.3% by weight, based on the total solids content of the NCO-terminated prepolymer.

[0017] The NCO content was determined by titration according to DIN EN ISO 11909:2007-05.

[0018] According to the present invention, the polydispersity is determined in accordance with DIN 55672-1:2016-03.

[0019] An "organic compound" contains at least one moiety that contains a carbon-hydrogen covalent bond.

[0020] According to the present invention, the term "aliphatic" is defined as a non-aromatic hydrocarbyl group that is saturated or unsaturated.

[0021] According to the present invention, the term "araliphatic" is defined as a hydrocarbyl moiety composed of non-aromatic, and saturated or unsaturated hydrocarbyl groups, directly bonded to an aromatic moiety.

[0022] According to the present invention, the term "alicyclic" or "cycloaliphatic" refers to optionally substituted carbocyclic or heterocyclic compounds or moieties that are non-aromatic (e.g., cycloalkanes, cycloalkenes or oxa-, thia-, aza- or thiazacycloalkanes). Particular examples are the cyclohexyl group, the cyclopentyl group, and their N- or O-heterocyclic derivatives, such as, for example, pyrimidine, pyrazine, tetrahydropyran or tetrahydrofuran.

[0023] According to the present invention, the term "polyol unit P" can include other intramolecular functional groups, such as, for example, urethane groups. Regardless of these intramolecular functional groups that may optionally be present, all "polyol units P" meet the definition of the general formula (I) of the present invention. These intramolecular functional groups can be formed, for example, by possible chain extension during the prepolymer synthesis.

[0024] According to the present invention, the NCO-terminated prepolymers having the general formula (I) contain urethane groups as intramolecular functional groups and are essentially free of other functional groups derived from NCO groups, such as, for example, isocyanurate groups. "Essentially" in this respect means that other functional groups than urethane groups are present only in very small amounts, such as are unavoidable, for example, during synthesis. Preferably, such other functional groups are present only in an amount of 5 mol % or less, more preferably 2 mol % or less, most preferably 0.5 mol % or less, based on the amount of urethane groups of the NCO-terminated prepolymer. The same definitions and preferred embodiments apply to the NCO-terminated prepolymers obtained or obtainable by the method of the present invention.

[0025] The mol% content of the urethane group in the general formula (I) and the mol% content of the other intramolecular functional groups not essentially contained therein, such as the "isocyanurate group", are determined by proton decoupling. 13 Calculated from the integration of the C-NMR spectrum. In the case of an NCO-terminated prepolymer based on 1,6-diisocyanatohexane (HDI) dissolved in CDCl3, the individual structural elements have the following chemical shifts (ppm): isocyanurate: 148.4 and urethane: 156.3.

[0026] In a first preferred embodiment, the NCO-terminated prepolymer of the present invention having general formula (I) is characterized in that the content of oligomers having a number average molecular weight of 1000 g / mol or less is 0.5% to 17% by weight, preferably 1.0% to 14% by weight, most preferably 1.5% to 10% by weight, based on the total solid content of the NCO-terminated prepolymer, which has the advantage that the solvent and chemical resistance of the cured composition is further increased.

[0027] In a preferred embodiment, the inventive NCO-terminated prepolymer having general formula (I) is characterized in that the NCO-terminated prepolymer has an NCO content of ≧7.5% to ≦11.0% by weight, which has the advantage that the number of reactive groups is minimized while the hardness of the coating is still sufficient.

[0028] In principle, the NCO-terminated prepolymer of the present invention having the general formula (I) can have any molecular weight known to a person skilled in the art. In a preferred embodiment, the NCO-terminated prepolymer of the present invention having the general formula (I) is characterized in that the NCO-terminated prepolymer has a number average molecular weight Mn of 1700 g / mol or more, preferably 1700 g / mol to 3500 g / mol or less, more preferably 1700 g / mol to 3100 g / mol or less. The average molecular weight Mn is determined as described above.

[0029] In a preferred embodiment, the inventive NCO-terminated prepolymers having general formula (I) are characterized in that they have an average NCO functionality of greater than 2.0, preferably greater than 2.7. The functionality is calculated using the following formula:

[0030]

number

[0031] Typically, the units Q in the inventive NCO-terminated prepolymers having general formula (I) are at least one aliphatic, cycloaliphatic, araliphatic and / or aromatic radical obtained by removal of an isocyanate group from a monomeric diisocyanate unit and / or at least one organic radical obtained by removal of an isocyanate group from a uretdione unit having two isocyanate groups.

[0032] Suitable monomeric diisocyanates OCN-Q-NCO have aliphatically, cycloaliphatically, araliphatically and / or aromatically bound isocyanate groups. The monomeric diisocyanates can be prepared by any desired method, for example by phosgenation, or by a phosgene-free route, for example by urethane cleavage.

[0033] For example, these monomeric diisocyanates (hereinafter also referred to as starting diisocyanates) have a molecular weight range of 168 to 400 g / mol, such as 1,4-butane diisocyanate, 1,5-diisocyanatopentane (PDI), 1,5-diisocyanato-2,2-dimethyl-pentane, 1,6-diisocyanatohexane (HDI), 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanatohexane, 1,8-diisocyanatohexane, 1,5-diisocyanatohexane, 1,6-diisocyanatohexane, 1,8-diisocyanatohexane, 1,5-diisocyanatohexane, 1,5-diisocyanatohexane, 1,6-diisocyanatohexane, 1,6-diisocyanatohexane, 1,8-diisocyanatohexane, 1,5-diisocyanatohexane, 1,5-diisocyanatohexane, 1,6-diisocyanatohexane, 1,6-diisocyanatohexane, 1,8-diisocyanatohexane, 1,5-diisocyanatohexane, 1,5-diisocyanatohexane, 1,6-diisocyanatohexane, 1,6-diisocyanatohexane, 1,6-diisocyanatohexane, 1,8-diisocyanatohexane, 1,6 ... Anatooctane, 1,9-diisocyanato-nonane, 1,10-diisocyanatodecane, 1,3- and 1,4-diisocyanatocyclohexane, 1,4-diisocyanato-3,3,5-trimethylcyclohexane, 1,3-diisocyanato-2-methylcyclohexane, 1,3-diisocyanato-4-methylcyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate;IPDI), 1-isocyanato-1-methyl-4(3)-isocyanatomethylcyclohexane, 2,4'- and 4,4'-diisocyanatodicyclohexylmethane (H12-MDI), 1,3- and 1,4-bis(isocyanatomethyl)cyclohexane, 4,4'-diisocyanato-3,3'-dimethyldicyclohexylmethane, 4,4'-diisocyanato-3,3',5,5'-tetramethyldicyclo-hexylmethane, 4,4'-diisocyanato-1,1'-bi(cyclohexyl), 4,4'-diisocyanato-3,3'-dimethyl-1,1'-bi(cyclohexyl), 4,4'-diisocyanato-2,2',5,5'-tetra-methyl-1,1'-bi(cyclohexyl), 1,8-diisocyanato-p-methane, 1,3-diisocyanatoadamantane, 1,3-dimethyl-5,7-diisocyanatoadamantane, 1,3- and 1,4-bis(isocyanatomethyl)benzene (XDI), 1,3- and 1,4-bis(1-isocyanato-1-methylethyl)benzene (TMXDI), bis(4-(1-isocyanato-1-methylethyl)phenyl)carbonate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4- and 2,6-toluylene diisocyanate and any mixtures of such diisocyanates, diphenylmethane-2,4'- and / or -4,4'-diisocyanate and naphthylene-1,5-diisocyanate and any mixtures of such diisocyanates. Other suitable diisocyanates can also be found, for example, in Justus Liebig's Annalen der Chemie, 562, 1949, 75-136.

[0034] Additionally or alternatively, OCN-Q-NCO is at least one uretdione polyisocyanate having two isocyanate groups.

[0035] Suitable uretdione units having two isocyanate groups are typically obtained by dimerizing the monomeric diisocyanates described herein or their polyisocyanates, optionally in the presence of a catalyst, by methods known in the art. Examples of optional dimerization catalysts are trialkylphosphines, aminophosphines and aminopyridines, such as dimethylaminopyridines and tris(dimethylamino)phosphine, as well as any other dimerization catalyst known to those skilled in the art. The outcome of the dimerization reaction depends, in a manner known to those skilled in the art, on the catalyst used, the process conditions and the diisocyanate used. In particular, it is possible to form products containing, on average, two or more uretdione groups per molecule, the number of uretdione groups being subject to a distribution. The uretdione units preferably contain, on average, 1 to 10 uretdione groups. Preferred uretdione units are prepared from the catalytic dimerization of PDI, HDI and / or IPDI.

[0036] In a preferred embodiment, the NCO-terminated prepolymers having general formula (I) of the present invention are characterized in that Q is independently at least one aliphatic and / or cycloaliphatic radical obtained by removal of an isocyanate group from a diisocyanate, preferably selected from the group consisting of 1,5-diisocyanatopentane, 1,6-diisocyanatohexane, isophorone diisocyanate, 2,4'- and 4,4'-diisocyanatodicyclohexylmethane, 1,3- and 1,4-bis-isocyanatomethylcyclohexane, 1,3- and 1,4-xylylene diisocyanate and mixtures selected from the aforementioned, more preferably selected from the group consisting of 1,5-diisocyanatopentane, 1,6-diisocyanatohexane and / or isophorone diisocyanate.

[0037] In general, the units P in the inventive NCO-terminated prepolymers having the general formula (I) are at least one alkyl radical obtained by removing a hydroxyl group from a polyol, preferably selected from the group consisting of polyether polyols, polyester polyols, polyurethane polyols, polysiloxane polyols, polycarbonate polyols, polybutadiene polyols, polyacrylate polyols, polymethacrylate polyols, copolymers of polyacrylate polyols and polymethacrylate polyols and mixtures thereof, more preferably selected from the group consisting of polyether polyols, polyester polyols, polyurethane polyols, polysiloxane polyols, polyacrylate polyols and mixtures thereof. In principle, these polyols are known to those skilled in the art.

[0038] Polyester polyol P(OH) p are obtained in a manner known per se by reacting a polyhydric alcohol, for example one of those mentioned above having 2 to 14 carbon atoms, with a stoichiometric or less amount of a polycarboxylic acid, a corresponding carboxylic acid anhydride, a corresponding polycarboxylic acid anhydride, a lower alcohol or a lactone.

[0039] The acids or acid derivatives used in the preparation of the polyester polyols may be aliphatic, cycloaliphatic and / or aromatic, and may be optionally substituted, for example by halogen atoms, and / or unsaturated. Examples of suitable acids are polybasic carboxylic acids or derivatives thereof having a molecular weight of 118 to 300 g / mol, such as succinic acid, adipic acid, sebacic acid, phthalic acid, isophthalic acid, trimellitic acid, phthalic anhydride, tetrahydrophthalic acid, maleic acid, maleic anhydride, dimeric and trimeric fatty acids, dimethyl terephthalate and bisglycol terephthalic acid esters.

[0040] Any desired mixtures of these starting compounds mentioned by way of example can also be used for the preparation of the polyester polyols.

[0041] The types of polyester polyols preferably used as polyol units P are those which can be prepared in a manner known per se from lactones and simple polyhydric alcohols, such as, for example, those mentioned above as starter molecules under ring opening. Suitable lactones for preparing these polyester polyols include β-propiolactone, γ-butyrolactone, δ-valerolactone, ε-caprolactone, 3,5,5- and 3,3,5-trimethylcaprolactone, or any mixture of such lactones.

[0042] Polyol P(OH) p Suitable polyhydroxyl compounds of the polycarbonate type as polyols are in particular the polycarbonate polyols known per se and which can be prepared, for example, by reacting dihydric alcohols, for example those mentioned above in the list of polyhydric alcohols having a molecular weight of 62 to 400 g / mol, with diaryl carbonates, for example diphenyl carbonate, dialkyl carbonates, for example dimethyl carbonate, or phosgene.

[0043] Polyol P(OH) p Polyhydroxyl compounds of the polyestercarbonate type which are suitable as such are in particular diols which contain ester and carbonate groups and which are known per se and can be obtained, for example according to the teaching of DE-A 1 770 245 or WO 03 / 002630, by reacting dihydric alcohols, for example with lactones of the abovementioned type, in particular ε-caprolactone, and subsequently reacting the polyesterdiols obtained with diphenyl carbonate or dimethyl carbonate.

[0044] Polyol P(OH) pSuitable polyether polyols as are in particular those having an average molecular weight, which can be calculated from the functionality and the hydroxyl number, of 800 to 3000 g / mol, preferably 900 to 2000 g / mol, more preferably 900 to 1500 g / mol, which can be obtained in a manner known per se by alkoxylation of suitable starter molecules. To prepare these polyether polyols, any desired polyhydric alcohol can be used as starter molecule, for example the simple polyhydric alcohols having 2 to 14 carbon atoms mentioned above. Suitable alkyl oxides for the alkoxylation reaction are in particular ethylene oxide and propylene oxide, which can be used in any desired order or in a mixture in the alkoxylation reaction.

[0045] Suitable polyether polyols P(OH) p is also a polyoxytetramethylene glycol known per se by polymerization of tetrahydrofuran.

[0046] Suitable polyester polyols P(OH) p can also be prepared by polycondensation of an aliphatic dicarboxylic acid and / or anhydride with an excess of a polyfunctional alcohol, having a number average molecular weight of 800-3000 g / mol, preferably 900-2000 g / mol, more preferably 900-1500 g / mol, wherein the polyfunctional alcohol is a branched aliphatic diol to the extent of at least 30% by weight, based on the total amount of polyfunctional alcohol used.

[0047] Polyester polyols of this kind are known. They can be prepared in a manner known per se, for example as described in Gubbels, E. et al., 2018, Polyesters.In: Ullmann's Encyclopedia of Industrial Chemistry: Wiley-VCH Verlag GmbH & Co. KGaA, URL: https: / / doi.org / 10.1002 / 14356007.a21_227.pub2. If necessary, catalytic amounts of standard esterification catalysts, such as acids, bases or transition metal compounds, for example titanium tetrabutoxide, can be used. The esterification reaction is generally carried out in a temperature range of about 80 to 260 ° C, preferably 100 to 230 ° C, until the desired values ​​of the hydroxyl number and acid number are obtained.

[0048] Starting compounds for the preparation of polyester polyols are any desired linear aliphatic or cycloaliphatic, saturated or unsaturated dicarboxylic acids or anhydrides having 4 to 12 carbon atoms, preferably 4 to 6 carbon atoms, and polyhydric aliphatic or cycloaliphatic alcohols, preferably diols and triols having 2 to 18 carbon atoms, preferably 2 to 6 carbon atoms.

[0049] Suitable dicarboxylic acids or anhydrides for the preparation of the polyester polyols are, for example, succinic acid, succinic anhydride, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, tetrahydrophthalic acid and tetrahydrophthalic anhydride, which can be used alone or in any desired mixture with one another.

[0050] Suitable polyfunctional alcohols for the preparation of polyester polyols are, for example, ethane-1,2-diol, propane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, heptane-1,7-diol, octane-1,8-diol, nonane-1,9-diol, decane-1,10-diol, dodecane-1,12-diol, cyclohexane-1,2- and -1,4-diol, cyclohexane-1,4-dimethanol, 4,4'-(1-methylethylidene)biscyclohexanol, propane-1,2,3-triol (glycerol), 1,1,1-trimethylolethane, hexane-1,2,6-triol, 1,1,1-trimethylolpropane, 2,2-bis(hydroxymethyl)propane-1,3-diol, diols, low molecular weight polyether diols such as diethylene glycol and dipropylene glycol, and branched aliphatic diols such as propane-1,2-diol, butane-1,3-diol, 2-methylpropanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), hexane-1,2-diol, 2-methylpentane-2,4-diol, 3-methylpentane-1,5-diol, 2-ethylhexane-1,3-diol, octane-1,2-diol, 2,2,4-trimethylpentane-1,5-diol, 2-butyl-2-ethylpropane-1,3-diol, 2,2,4- and / or 2,4,4-trimethylhexanediol, decane-1,2-diol or any desired mixture of such alcohols. According to the present invention, the polyfunctional alcohol is a branched aliphatic diol of the type mentioned to the extent of at least 30% by weight, preferably at least 35% by weight, more preferably at least 40% by weight, based on the total amount of polyfunctional alcohol used.

[0051] The starter molecules used for the ring-opening polymerization can be, for example, the di- or trifunctional alcohols mentioned above as suitable starter compounds for the preparation of other suitable polyester polyols or any desired mixtures of these alcohols.

[0052] The preparation of ε-caprolactone polyester polyols by ring-opening polymerization is generally carried out in the presence of a catalyst, such as a Lewis or Bronsted acid, an organotin or titanium compound, at temperatures between 20 and 200°C, preferably between 50 and 200°C.

[0053] Preferred polyester polyols are those prepared using butane-1,4-diol, diethylene glycol, neopentyl glycol, hexane-1,6-diol, glycerol and / or 1,1,1-trimethylolpropane as starter molecules.

[0054] In a preferred embodiment, the NCO-terminated prepolymer having general formula (I) of the present invention is characterized in that each P in general formula (I) is independently at least one organic radical obtained by removing a hydroxyl group from a polyol having an average molecular weight of 800 g / mol to 3000 g / mol and an OH functionality of more than 2 to 3, preferably an average molecular weight of 900 g / mol to 2000 g / mol and an OH functionality of more than 2 to 3, more preferably an average molecular weight of 900 g / mol to 1500 g / mol and an OH functionality of more than 2 to 3. More preferably, each P in general formula (I) is independently at least one polyol unit having an average molecular weight of 800 g / mol to 3000 g / mol and an OH functionality of more than 2 to less than 3, preferably an average molecular weight of 900 g / mol to 2000 g / mol and an OH functionality of more than 2 to less than 3, more preferably an average molecular weight of 900 g / mol to 1500 g / mol and an OH functionality of more than 2 to less than 3.

[0055] It is further preferred that P in the general formula (I) is at least one organic radical obtained by removing a hydroxyl group from a polyester polyol having an average molecular weight of 800 g / mol to 3000 g / mol and an OH functionality of more than 2 to 3, preferably an average molecular weight of 900 g / mol to 2000 g / mol and an OH functionality of more than 2 to 3, and more preferably an average molecular weight of 900 g / mol to 1500 g / mol and an OH functionality of more than 2 to 3.

[0056] In a preferred embodiment, the NCO-terminated prepolymer of the present invention having general formula (I) is characterized in that p's are each independently a number equal to or greater than 2 and less than 4.5, preferably greater than 2 and less than 3.

[0057] In principle, the NCO-terminated prepolymers of the invention can contain or be diluted with a solvent that is inert towards isocyanate groups, but this is not essential. Suitable solvents are, for example, ethyl acetate, butyl acetate, ethylene glycol monomethyl or monoethyl ether acetate, 1-methoxyprop-2-yl acetate, 3-methoxy-n-butyl acetate, acetone, 2-butanone, 4-methyl-2-pentanone, cyclohexanone, toluene, xylene, chlorobenzene, white spirit, more highly substituted aromatic compounds such as, for example, Solventnaphtha, Solvesso®, Isopar®, Nappar®, Varsol® (ExxonMobil Chemical Central Europe, Cologne, Germany) and Shellsol® (Shell Deutschland Oil). GmbH, Hamburg, Germany), as well as solvents such as propylene glycol diacetate, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, diethylene glycol ethyl and butyl ether acetate, N-methylpyrrolidine and N-methylcaprolactam, or any desired mixtures of such solvents.

[0058] The present invention further relates to a method for preparing an inventive NCO-terminated prepolymer having the general formula (I), comprising the following steps: a) adding at least one polyol having a hydroxyl group functionality of ≧2 to less than 3 and a polydispersity of ≧1.5 to a heated excess of at least one monomeric diisocyanate and / or at least one uretdione having two isocyanate groups in a ratio of NCO:OH groups of 4:1 to 20:1 to form urethane groups; b) removing excess monomeric diisocyanate by distillation to less than 0.5 wt. %, preferably less than 0.3 wt. %, more preferably less than 0.1 wt. %, based on the total solids content of the NCO-terminated prepolymer, to obtain an NCO-terminated prepolymer; and c) optionally adding at least one solvent which is inert towards isocyanate groups The present invention relates to a method comprising the steps of:

[0059] The at least one polyol and the at least one monomeric diisocyanate and / or the at least one uretdione having two isocyanate groups used in the process of the present invention follow the same definitions and preferred embodiments outlined above in the description and claims of the NCO-terminated prepolymers of the present invention, unless expressly indicated to the contrary.

[0060] The polydispersity of the polyols applied in the process of the present invention can be determined according to DIN 55672-1:2016-03.

[0061] At least one monomeric diisocyanate and / or at least one uretdione having two isocyanate groups is reacted with at least one polyol at a temperature preferably between 20 and 200°C, preferably between 40 and 160°C, more preferably between 60 and 140°C.

[0062] In a preferred embodiment of the method of the present invention, the at least one polyol has an average molecular weight of 800 g / mol to 3000 g / mol, preferably 900 g / mol to 2000 g / mol, most preferably 900 g / mol to 1500 g / mol. This has the advantage that the content of oligomers having a number average molecular weight of 1000 g / mol or less in the NCO-terminated prepolymer of the present invention can be further reduced to 17% by weight or less, more preferably 0.5% by weight to 17% by weight or less, even more preferably 1.0% by weight to 14% by weight or less, most preferably 1.5% by weight to 10% by weight or less, based on the total solids content of the NCO-terminated prepolymer.

[0063] In general, it is possible to directly use a polyol already having such a specified minimum average molecular weight or, if the polyol to be used has a lower average molecular weight, it is possible to purify it, preferably in a distillation step, before the addition in step a) to increase the average molecular weight to the value mentioned in the preceding paragraph.

[0064] Alternatively or additionally, it is preferred to carry out step b) of the process of the invention at a higher temperature than is required for the removal of the excess monomeric diisocyanate, in order to further reduce the content of oligomers with a number average molecular weight of less than or equal to 1000 g / mol to less than or equal to 17% by weight, more preferably from 0.5% to 17% by weight, even more preferably from 1.0% to 14% by weight, most preferably from 1.5% to 10% by weight, based on the total solids content of the NCO-terminated prepolymer. Said higher temperature depends on the type of monomer to be removed and can be determined by the skilled person by simple experiments without undue burden, for example by taking the thin film evaporation temperature of the monomeric diisocyanate to be removed and increasing this temperature by at least 10° C. but not more than 200° C.

[0065] The process of the invention can be carried out without catalysis. However, if necessary, suitable catalysts can be used to accelerate the urethanization reaction. These are conventional catalysts known from polyurethane chemistry, such as tertiary amines, such as triethylamine, tributylamine, dimethylbenzylamine, diethylbenzylamine, pyridine, methylpyridine, dicyclohexylmethylamine, dimethylcyclohexylamine, N,N,N',N'-tetramethyldiaminodiethyl ether, bis(dimethylaminopropyl)urea, N-methyl- / N-ethylmorpholine, N-cocomorpholine, N-cyclohexylmorpholine, N,N,N',N'-tetramethylethylenediamine, N,N, N',N'-Tetramethyl-1,3-butanediamine, N,N,N',N'-Tetramethyl-1,6-hexanediamine, pentamethyldiethylenetriamine, N-Methylpiperidine, N-Dimethylaminoethylpiperidine, N,N'-Dimethylpiperazine, N-Methyl-N'-dimethylaminopiperazine, 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU), 1,2-Dimethylimidazole, 2-Methylimidazole, N,N-Dimethylimidazole-β-phenylethylamine, 1,4-Diazabicyclo[2.2.2]octane, bis(N,N-dimethylaminoethyl)adipate; alkanolamine compounds, such as triethanolamine, triisopropanolamine, N-methyl- and N-ethyldiethanol, dimethylaminoethanol, 2-(N,N-dimethylaminoethoxy)ethanol, N,N',N''-tris(dialkylaminoalkyl)hexahydrotriazines, such as N,N',N''-tris(dimethylaminopropyl)-s-hexahydrotriazine and / or bis(dimethylaminoethyl)ether; metal salts, such as inorganic and / or organic compounds of iron, lead, bismuth, zinc and / or tin in the normal oxidation states, such as iron(II) chloride, iron(III) chloride, bismuth(III), bismuth 2-ethylhexanoate ( III), bismuth(III) octanoate, bismuth(III) neodecanoate, zinc chloride, zinc 2-ethylcaproate, tin(II) octanoate, tin(II) ethylcaproate, tin(II) palmitate, dibutyltin(IV) dilaurate (DBTL), dibutyltin(IV) dichloride or lead octanoate; for example, 2,3-dimethyl-3,4,5,6-tetrahydropyrimidine; tetraalkylammonium hydroxides, for example, tetramethylammonium hydroxide; alkali metal hydroxides, for example, sodium hydroxide, and alkali metal alkoxides, for example, sodium methoxide and potassium isopropoxide, as well as alkali metal salts of long-chain fatty acids having 10 to 20 carbon atoms and optionally a side chain OH group.

[0066] These catalysts are preferably used in the process of the present invention in an amount of from 0.001 to 5% by weight, more preferably from 0.005 to 1% by weight, based on the total weight of all co-reactants, if at all, and may be added before the start of the reaction or at any time during the reaction.

[0067] The progress of the reaction in the process of the invention can be monitored by determining the NCO content by titration means, for example according to DIN EN ISO 11909:2007-05. Once the desired NCO content has been reached, preferably when an NCO content theoretically corresponding to complete conversion of isocyanate and hydroxyl groups has been reached in the reaction mixture, any urethanization catalyst used is deactivated, preferably by addition of a suitable catalyst poison.

[0068] Such catalyst poisons are, for example, inorganic acids such as hydrochloric acid, phosphorous acid or phosphoric acid, acid chlorides such as acetyl chloride, benzoyl chloride or isophthaloyl chloride, sulfonic acids and sulfonate esters such as methanesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid, perfluorobutanesulfonic acid, dodecylbenzenesulfonic acid, methyl and ethyl p-toluenesulfonate, mono- and dialkyl phosphates such as monotridecyl phosphate, dibutyl phosphate and dioctyl phosphate, and silylation acids such as trimethylsilyl methanesulfonate, trimethylsilyl trifluoromethanesulfonate, tris(trimethylsilyl)phosphate and diethyltrimethylsilyl phosphate.

[0069] The amount of catalyst poison required for catalyst deactivation is guided by the amount of catalyst used. Generally, an equivalent amount of catalyst poison is used based on the amount of urethanization catalyst used at the beginning. However, when catalyst losses occurring during the reaction are taken into account, even 20-80 equivalent % of catalyst poison, based on the amount of catalyst initially used, may be sufficient to stop the reaction.

[0070] The process of the present invention is preferably carried out without solvent. However, if necessary, suitable solvents inert to the reactive groups of the starting components can also be used. Suitable solvents are, for example, ethyl acetate, butyl acetate, ethylene glycol monomethyl or monoethyl ether acetate, 1-methoxyprop-2-yl acetate, 3-methoxy-n-butyl acetate, acetone, 2-butanone, 4-methyl-2-pentanone, cyclohexanone, toluene, cyclohexanone, xylene, chlorobenzene, white spirit, more highly substituted aromatic compounds, such as, for example, Solventnaphtha, Solvesso, R , Isopar R , Nappar R , Varsol R (ExxonMobil Chemical Central Europe, Cologne, Germany) and Shellsol R (Shell Deutschland Oil GmbH, Hamburg, Germany), as well as propylene glycol diacetate, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, diethylene glycol ethyl and butyl ether acetates, N-methylpyrrolidone and N-methylcaprolactam, or any desired mixtures of such solvents.

[0071] Independently of the optional use of a solvent in step a) or b), the method of the invention comprises the addition of at least one solvent inert towards isocyanate groups to reach a preferred viscosity of less than 2000 mPas at 23° C. measured according to DIN EN ISO 3219:1994-10 in optional step c). Such optional solvent is preferably selected from the list above. If step c) is carried out, a suitable solvent is preferably added in an amount to achieve a solids content of more than 50% by weight, more preferably more than 80% by weight, most preferably more than 95% by weight.

[0072] The present invention further relates to a compound represented by the general formula (I) [ka] wherein P, Q and p are defined as follows: P each independently represents at least one organic radical obtained by removing a hydroxyl group from a polyol unit; Q each independently represents at least one organic radical obtained by removing an isocyanate group from a monomeric diisocyanate unit and / or at least one organic radical obtained by removing an isocyanate group from a uretdione unit having two isocyanate groups; and p each independently is a number equal to or greater than 2.0, and Here, the NCO-terminated prepolymer is an NCO content of 6.5% by weight or more and 12.0% by weight or less, based on the total solids content of the NCO-terminated prepolymer; and a content of not more than 17% by weight of oligomers having a number average molecular weight of not more than 1000 g / mol, based on the total solids content of the NCO-terminated prepolymer; and Contains less than 0.5% by weight of monomeric diisocyanates, based on the total solids content of the NCO-terminated prepolymer and Here, P is at least one polyester polyol unit A) prepared from an aliphatic dicarboxylic acid and / or anhydride and an excess of a polyfunctional alcohol, the polyfunctional alcohol being a branched aliphatic diol to the extent of at least 30% by weight, based on the total amount of the polyfunctional alcohol, with an average functionality of 1.9 to 2.3 and a number average molecular weight of 300 to 3000 g / mol; and B) at least one polycaprolactone polyester unit with an average functionality of 2.0 to 3.0 and a number average molecular weight of 176 to 2000 g / mol; Does not contain a mixture of Here, the polyester unit A) is 15% by weight to 70% by weight in the total amount of the polyester units A) and B) in the NCO-terminated prepolymer. The present invention relates to NCO-terminated prepolymers, preferably for manual coating applications, having the formula:

[0073] With respect to this embodiment, it is further preferred that P does not contain polycaprolactone polyester units with an average functionality of 2.0 to 3.0 and a number average molecular weight of 176 to 2000 g / mol.

[0074] All embodiments and preferences disclosed herein for the other aspects of the invention can be combined with the two preceding aspects, but the preferred polyols P(OH) p may be combined, except that the components are selected from those disclosed such that mixtures of polyester units A) and B) are excluded, and that the polydispersity of the NCO-terminated prepolymers of the present invention may be less than 2.0, but is preferably greater than or equal to 2.0.

[0075] The present invention therefore further relates to a method for preparing an inventive NCO-terminated prepolymer having the general formula (I), comprising the following steps: a) adding at least one polyol having a hydroxyl functionality of ≥2 but <3 to a heated excess of at least one monomeric diisocyanate and / or at least one uretdione having two isocyanate groups, with an NCO:OH group ratio of 4:1 to 20:1, to form urethane groups; b) removing excess monomeric diisocyanate by distillation down to less than 0.5 wt. %, preferably less than 0.3 wt. %, more preferably less than <0.1 wt. %, based on the total solids content of the NCO-terminated prepolymer, to obtain the NCO-terminated prepolymer. and c) optionally adding at least one solvent Including, wherein at least one polyol is at least one polyester polyol unit A) prepared from an aliphatic dicarboxylic acid and / or anhydride and an excess of a polyfunctional alcohol, the polyfunctional alcohol being a branched aliphatic diol to the extent of at least 30% by weight, based on the total amount of the polyfunctional alcohol, with an average functionality of 1.9 to 2.3 and a number average molecular weight of 300 to 3000 g / mol; and B) at least one polycaprolactone polyester unit with an average functionality of 2.0 to 3.0 and a number average molecular weight of 176 to 2000 g / mol; Does not contain a mixture of Here, the polyester unit A) in the total amount of the polyester units A) and B) is 15% by weight to 70% by weight in the NCO-terminated prepolymer. It concerns the method.

[0076] It is further preferred for this method that at least one polyol is completely free of polycaprolactone polyester units with an average functionality of 2.0 to 3.0 and a number average molecular weight of 176 to 2000 g / mol.

[0077] The at least one polyol and the at least one monomeric diisocyanate and / or the at least one uretdione having two isocyanate groups used in the process of the present invention follow the same definitions and preferred embodiments as outlined above in the description, aspects and claims of the NCO-terminated prepolymers of the present invention, unless expressly indicated to the contrary.

[0078] The special physicochemical properties of the NCO-terminated prepolymers of the present invention make them particularly suitable for use in curable compositions for coatings, adhesives and / or sealants, which are a further aspect of the present invention.

[0079] The present invention further relates to a two-component system comprising or consisting of component A) which comprises at least one NCO-terminated prepolymer according to the invention and component B) which comprises at least one compound which contains at least one Zerewitinoff-active group.

[0080] Suitable compounds containing at least one Zerewitinoff-active group are, for example, conventional polymeric polyether polyols, polyester polyols, polycarbonate polyols and / or polyacrylate polyols known from polyurethane chemistry, which usually have a number-average molecular weight of 200 to 22 000, preferably 250 to 18 000, particularly preferably 250 to 12 000. An extensive overview of suitable polymeric polyols can be found, for example, in N. Adam et al.: "Polyurethanes", Ullmann's Encyclopedia of Industrial Chemistry, Electronic Release, 7th edition, chapters 3.2-3.4, Wiley-VCH, Weinheim 2005.

[0081] As an alternative to the abovementioned hydroxy-functional compounds, polyamines, such as the polyaspartic acid derivatives known from EP-B 0 403 921, or polyamines in which the amino groups are present in blocked form, such as polyketimines, polyaldimines or oxazolanes, are also suitable as isocyanate-reactive binders. Free amino groups are formed from these blocked amino groups under the influence of moisture and, in the case of oxazolanes, free hydroxyl groups are also formed which react with the isocyanate groups of the polyisocyanates to crosslink.

[0082] In a preferred embodiment, the at least one compound comprising at least one Zerewitinoff active group is selected from polyester polyols, polyether polyols, polyurethane polyols, polyacrylate polyols, polymethacrylate polyols, polycarbonate polyols and mixtures thereof.

[0083] In another preferred embodiment, said component B) comprises less than 5% by weight, preferably less than 2% by weight, more preferably less than 1% by weight of a solvent. This has the advantage of further improving the economic and operational safety characteristics, since volatile organic emissions are significantly reduced without adversely affecting the performance of the two-component system of the present invention. Suitable solvents can be selected from the solvents commonly used for such two-component systems, for example from the list described above for the NCO-terminated prepolymer of the present invention and the method of the present invention.

[0084] If appropriate, further auxiliary agents and additives that are customary in the coating field can be added to the spray system.Examples of suitable auxiliary agents and additives are leveling agents, color pigments, filler materials, matting agents, inorganic or organic pigments, light stabilizers, lacquer additives such as dispersants, leveling agents, thickeners, defoamers and other auxiliary agents, adhesives, fungicides, bactericides, stabilizers or inhibitors and catalysts or emulsifiers.

[0085] In order to control the curing rate, it is possible to use suitable catalysts in the formulation of the coating composition, for example the urethanization catalysts customary in isocyanate chemistry as already mentioned above, for example as catalysts for the preparation of the NCO-terminated prepolymers of the invention. If catalysts are used in the two-component systems of the invention, they are preferably contained in compound B).

[0086] In all the above mentioned uses for the NCO-terminated prepolymers of the invention, they can be used alone or in blends with optional further polyisocyanates having aliphatically, cycloaliphatically, araliphatically and / or aromatically bound isocyanate groups, for example to increase the crosslink density, more preferably as isocyanate components, as described by Laas et al., J. Prakt. Chem. 336, 1994, 185-200, DE-A 1 670 666, DE-A 3 700 209, DE-A 3 900 053, EP-A 0 330 966, EP-A 0 336 205, EP-A 0 339 396 and EP-A 0 798. 299, can be used in blends with known paint polyisocyanates having uretdione, isocyanurate, iminooxadiazinedione, urethane, allophanate, biurethane and / or oxadiazinetrione structures.

[0087] In the inventive two-component systems for polyurethane and / or polyurea paints and coatings, which comprise the inventive NCO-terminated prepolymers as a component of the crosslinker component or consist of a crosslinker component for polyols, polythiols and / or polyamines, the co-reactant is conventionally present in an amount such that there are 0.5 to 3, preferably 0.6 to 2.0, more preferably 0.8 to 1.6 Zerewitinoff-active groups (also referred to herein as isocyanate-reactive groups) per isocyanate group.

[0088] The present invention further comprises the steps of: i) applying at least one two-component system of the invention onto at least one substrate or into a cavity, and ii) exposing the deposited composition to a temperature of from 0 to 120° C., preferably from 20 to 90° C., more preferably from 20 to 60° C., to cure the deposited cured composition. The present invention relates to a method for curing a composition on a substrate or within a cavity, comprising:

[0089] It is preferred to mix component A) and component B) of the two-component system to obtain a mixture immediately before applying the two-component system on at least one substrate or in a cavity, which means that said mixture is preferably applied in step i). When the deposited composition is cured, the cured composition forms a solid on the substrate or in the cavity. If the system is deposited on at least one substrate, such a solid is preferably a coating or an adhesive. If it is an adhesive, it is preferred to add a second substrate in a further step between steps i) and ii) or to directly add such a second substrate in step i). If the system is deposited in a cavity, such a solid is preferably a sealant or a foam.

[0090] Suitable substrates for the coatings, adhesives and / or sealants formulated using the NCO-terminated prepolymers of the invention or the two-component systems of the invention include any desired substrate, such as metal, wood, glass, stone, ceramic materials, concrete, rigid and flexible plastics, textiles, leather, and paper, which may optionally be coated with a conventional primer prior to coating.

[0091] The present invention further relates to a cured article obtainable or obtained by the method of the present invention for curing a composition on a substrate or in a cavity. In one preferred embodiment, the cured composition is a refinish coating and the substrate is a refinish substrate. In this embodiment, the cured composition is preferably an automotive refinish coating and the substrate is a refinish automotive substrate. In another preferred embodiment, the cured composition is an architect's interior foam or sealant.

[0092] A further aspect of the present invention is the use of either the inventive NCO-terminated prepolymers or the inventive two-component systems for coatings, adhesives and / or sealants, in particular in automotive refinishing applications, or in particular for foams and / or sealants in the building industry.

[0093] The present invention relates in particular to the following embodiments: According to a first aspect, the present invention relates to a compound of general formula (I) [ka] wherein P, Q and p are defined as follows: P each independently at least one organic radical obtained by removing a hydroxyl group from a polyol unit having an average molecular weight of ≧800 g / mol to ≦3000 g / mol and an OH functionality of ≧2 to ≦3; Q each independently represents at least one aliphatic and / or cycloaliphatic radical obtained by removing an isocyanate group from a diisocyanate, and p each independently is a number equal to or greater than 2.0, and Here, the NCO-terminated prepolymer is an NCO content of 6.5% by weight or more and 12.0% by weight or less, based on the total solids content of the NCO-terminated prepolymer; and a content of not more than 17% by weight of oligomers having a number average molecular weight of not more than 1000 g / mol, based on the total solids content of the NCO-terminated prepolymer; and a monomeric diisocyanate content of less than <0.5% by weight, based on the total solids content of the NCO-terminated prepolymer; and Polydispersity of 2.0 or greater have The present invention relates to an NCO-terminated prepolymer for coating applications having the formula:

[0094] According to a second aspect, the present invention relates to the NCO-terminated prepolymer according to the first aspect, characterized in that the content of oligomers having a number average molecular weight of 1000 g / mol or less is 0.5% by weight or more and 17% by weight or less, preferably 1.0% by weight or more and 14% by weight or less, and most preferably 1.5% by weight or more and 10% by weight or less, based on the total solid content of the NCO-terminated prepolymer.

[0095] According to a third aspect, the present invention relates to an NCO-terminated prepolymer according to the first or second aspect, characterized in that the NCO-terminated prepolymer has an NCO content of 7.5% by weight or more and 11.0% by weight or less.

[0096] According to a fourth aspect, the present invention relates to an NCO-terminated prepolymer according to any one of the preceding aspects, characterized in that the NCO-terminated prepolymer has a number average molecular weight Mn of 1700 g / mol or more, preferably 1700 g / mol to 3500 g / mol or less, more preferably 1700 g / mol to 3100 g / mol or less.

[0097] According to a fifth aspect, the present invention relates to an NCO-terminated prepolymer according to any one of the preceding aspects, characterized in that the NCO-terminated prepolymer has an average NCO functionality of more than 2.0, preferably more than 2.7.

[0098] According to a sixth aspect, the invention relates to an NCO-terminated prepolymer according to any one of the preceding aspects, characterized in that Q in general formula (I) is each independently at least one aliphatic and / or cycloaliphatic radical obtained by removal of an isocyanate group from a diisocyanate selected from the group consisting of 1,5-diisocyanatopentane, 1,6-diisocyanatohexane, isophorone diisocyanate, 2,4'- and 4,4'-diisocyanatodicyclohexylmethane, 1,3- and 1,4-bis-isocyanatomethylcyclohexane, 1,3- and 1,4-xylylene diisocyanate, and mixtures selected from the aforementioned, preferably from a diisocyanate selected from the group consisting of 1,5-diisocyanatopentane, 1,6-diisocyanatohexane and / or isophorone diisocyanate.

[0099] According to a seventh aspect, the present invention relates to an NCO-terminated prepolymer according to any one of the preceding aspects, characterized in that in general formula (I) P is each independently at least one polyol unit having an average molecular weight of ≧900 g / mol to ≦2000 g / mol and an OH functionality of ≧2 to ≦3, more preferably an average molecular weight of ≧900 g / mol to ≦1500 g / mol and an OH functionality of ≧2 to ≦3.

[0100] According to an eighth aspect, the present invention relates to an NCO-terminated prepolymer according to any one of the first to sixth aspects, characterized in that in general formula (I), P is independently at least one polyester polyol unit having an average molecular weight of 800 g / mol to 3000 g / mol and an OH functionality of more than 2 and less than 3, preferably an average molecular weight of 900 g / mol to 2000 g / mol and an OH functionality of more than 2 and less than 3, more preferably an average molecular weight of 900 g / mol to 1500 g / mol and an OH functionality of more than 2 and less than 3.

[0101] According to a ninth aspect, the present invention relates to an NCO-terminated prepolymer according to any one of the preceding aspects, characterized in that p in general formula (I) is, independently of each other, a number equal to or larger than 2 and smaller than 4.5, preferably greater than 2 and smaller than 3.

[0102] According to a tenth aspect, the present invention provides a method for producing a pharmaceutical composition comprising the steps of: a) adding at least one polyol having a hydroxyl group functionality of ≧2 to less than 3 and a polydispersity of ≧1.5 to a heated excess of at least one monomeric diisocyanate in a ratio of NCO:OH groups of 4:1 to 20:1 to form urethane groups; b) removing excess monomeric diisocyanate by distillation down to less than 0.5 wt.%, preferably less than 0.3 wt.%, more preferably less than <0.1 wt.%, based on the total solids content of the NCO-terminated prepolymer, to obtain the NCO-terminated prepolymer; and c) optionally adding at least one solvent which is inert towards isocyanate groups. The present invention relates to a method for producing an NCO-terminated prepolymer according to any one of aspects 1 to 9, comprising:

[0103] According to an eleventh aspect, the present invention relates to the method according to the tenth aspect, characterized in that at least one polyol has an average molecular weight of 800 g / mol or more and 3000 g / mol or less, preferably 900 g / mol or more and 2000 g / mol or less, more preferably 900 g / mol or more and 1500 g / mol or less.

[0104] According to a twelfth aspect, the present invention relates to the use of an NCO-terminated prepolymer according to any one of the aspects 1 to 9 or obtainable by the method according to the tenth or eleventh aspect, in a curable composition for a coating, adhesive and / or sealant.

[0105] According to a thirteenth aspect, the present invention relates to a two-component system comprising component A) which comprises at least one NCO-terminated prepolymer according to any one of aspects 1 to 9, and component B) which comprises at least one compound which comprises at least one Zerewitinoff-active group.

[0106] According to a fourteenth aspect, the invention relates to a two-component system according to aspect 13, characterized in that component B) comprises less than 5% by weight, preferably less than 2% by weight, more preferably less than 1% by weight of organic solvents.

[0107] According to a fifteenth aspect, the present invention provides a method for producing a pharmaceutical composition comprising the steps of: i) applying at least one two-component system according to the thirteenth or fourteenth aspect onto at least one substrate; and ii) exposing the deposited composition to a temperature of from 0 to 120° C., preferably from 20 to 90° C., more preferably from 20 to 60° C., to cure the deposited cured composition. The present invention relates to a method for curing a composition on a substrate, comprising:

[0108] According to a sixteenth aspect, the present invention relates to a cured article obtainable or obtained, preferably directly obtained, by the method according to the fifteenth aspect.

[0109] The present invention will be described with reference to examples which should not be construed as limiting. EXAMPLES

[0110] Working Example: All percentages are by weight unless otherwise stated.

[0111] The NCO content was determined by titration according to DIN EN ISO 11909:2007-05.

[0112] The residual monomer content was determined by gas chromatography with an internal standard in accordance with DIN EN ISO 10283:2007-11.

[0113] All viscosity measurements were performed using a Physica MCR 51 rheometer from Anton Paar Germany GmbH (Germany) at a shear rate of 250 s according to DIN EN ISO 3219:1994-10.

[0114] The number average molecular weights reported for the starting polyols were calculated from the OH number and OH functionality, respectively.

[0115] The content of oligomers with a number average molecular weight below 1000 g / mol is given as the number average molecular weight Mn determined by gel permeation chromatography (GPC at 23 °C) in tetrahydrofuran as solvent. The measurement is carried out as described in DIN 55672-1:2016-03: "Gel permeations chromatographie, Teil 1-Tetrahydrofuran als Elutionsmittel" (SECurity GPC-System from PSS Polymer Service, flow rate 1,0 ml / min; column: 2 x PSS SDV linear M, 8 x 300 mm, 5 μm; RID-detector). Samples of polystyrene standards of known molecular weight were used for calibration. The calculation of the number average molecular weight was carried out by the software. The baseline values ​​and the evaluation thresholds were determined according to DIN 55672-1 mentioned above.

[0116] The NCO functionality is calculated using the following formula:

[0117]

number

[0118] The polydispersity is determined in accordance with DIN 55672-1:2016-03.

[0119] Polyols: Polyester polyol 1: 19.0 parts by weight of trimethylolpropane, 13.8 parts by weight of neopentyl glycol, 23.1 parts by weight of 1,3-butane-1,3-diol, and 56.3 parts by weight of isophthalic acid were weighed into a flask and heated gradually to 200° C. at standard pressure with stirring, during which about 12.2 parts by weight of water were distilled off. The removal of water was complete after about 20 hours. The polyester polyol thus obtained had the following characteristic data: OH value 264mgKOH / g OH functionality 2.7 Acid value 4.2mgKOH / g Polydispersity 1.9 Average molecular weight 988g / mol Viscosity (75℃) 22400mPas

[0120] Polyester polyol 2: 17.2 parts by weight of neopentyl glycol, 13.3 parts by weight of butane-1,4-diol, 17.5 parts by weight of hexane-1,6-diol, 4.4 parts by weight of 2,2,4-trimethylpentane-1,3-diol, 4.4 parts by weight of 2-butyl-2-ethylpropane-1,3-diol and 43.2 parts by weight of adipic acid were weighed into a flask and heated gradually to 200° C. at standard pressure with stirring in the presence of 25 ppm of tin(II) chloride as a catalyst, during which about 5 parts by weight of water were distilled. After the removal of water was complete, a vacuum (15 mbar) was gradually applied over a period of about 4 hours, and the reaction was completed under these conditions within about 15 hours. The polyester polyol thus obtained had the following characteristic data: OH value 260mgKOH / g OH functionality 2.0 Acid value 0.2mg KOH / g Polydispersity 2.0 Average molecular weight 431g / mol Viscosity (25℃) 810mPas

[0121] Polyester polyol 3: ε-caprolactone polyesters using hexane-1,6-diol as starting material OH value 172mgKOH / g OH functionality 2.0 Acid value: 0.02mgKOH / g Polydispersity 1.3 Average molecular weight 650g / mol Viscosity (50℃) 80mPas

[0122] Desmophen 1110 BD: Linear polypropylene ether polyol, Covestro Deutschland AG OH value 112mgKOH / g OH functionality 2.0 Acid value: less than 0.1mgKOH / g Polydispersity 1.1 Viscosity (25℃) 140mPas

[0123] NCO-terminated prepolymer: Example 1 (Invention) 1640 g of hexamethylene diisocyanate (HDI) was heated under nitrogen to a temperature of 100° C. 1382 g of polyester polyol with a functionality of 2.7 and Mn of 988 g / mol was preheated to 80° C. and then added to the mixture via a dropping funnel over 2 hours. The mixture was stirred for another 2 hours until the NCO content indicated complete conversion. The excess HDI was subsequently removed by thin-film evaporation at a temperature of 115° C. and a pressure of 0.06 mbar. The resulting product was a slightly yellow, transparent NCO-terminated prepolymer with the following analytical characteristics: A content of 17% by weight of oligomers having a number average molecular weight of less than or equal to 1000 g / mol, based on the total solids content of the NCO-terminated prepolymer. Mn 1700g / mol NCO content 10.8% Polydispersity 2.0 Viscosity (80℃) 8800mPas Residual monomer 0.16% The prepolymer was dissolved in methoxypropyl acetate (MPA) at 30%.

[0124] Example 2 (Invention) 750 g of polyester polyol with functionality 2.7 and Mn 988 g / mol were purified by thin film evaporation at 195° C. and a pressure of 0.07 mbar.

[0125] 1630 g of hexamethylene diisocyanate (HDI) was heated to a temperature of 100° C. under nitrogen. 442 g of predistilled polyester polyol 1 (Mn of 1110 g / mol) was preheated to 80° C. and then added to the mixture via a dropping funnel over 4 hours. The mixture was stirred for another 2 hours until the NCO content indicated complete conversion. The excess HDI was subsequently removed by thin-film evaporation at a temperature of 115° C. and a pressure of 0.02 mbar. The resulting product was a slightly yellow, transparent NCO-terminated prepolymer with the following analytical characteristics: A content of 3% by weight of oligomers having a number average molecular weight of less than or equal to 1000 g / mol, based on the total solids content of the NCO-terminated prepolymer. Mn 2700g / mol NCO content 9.2% Polydispersity 2.6 Viscosity (80℃) 42100mPas Residual monomer 0.06%

[0126] The prepolymer was dissolved in methoxypropyl acetate (MPA) at 35%.

[0127] Example 3 (Invention) 750 g of polyester polyol with functionality 2.7 and Mn 988 g / mol were purified by thin film evaporation at 195° C. and a pressure of 0.07 mbar.

[0128] 1580 g of isophorone diisocyanate (IPDI) was heated to a temperature of 100° C. under nitrogen. 390 g of predistilled polyester polyol 1 (Mn of 1110 g / mol) was preheated to 80° C. and then added to the mixture via a dropping funnel over 6 hours. The mixture was stirred for an additional hour until the NCO content indicated complete conversion. The excess IPDI was subsequently removed by thin-film evaporation at a temperature of 180° C. and a pressure of 0.02 mbar. The resulting product was a yellow, transparent, NCO-terminated prepolymer with the following analytical characteristics: A content of 3% by weight of oligomers having a number average molecular weight of less than or equal to 1000 g / mol, based on the total solids content of the NCO-terminated prepolymer. Mn 3100g / mol NCO content 7.6% Polydispersity 3.3 Viscosity at 35% EA (23℃) 980mPas Residual monomer 0.24% The prepolymer was dissolved in ethyl acetate (EA) at 35%.

[0129] Example 4 (Comparison) 920 g of isophorone diisocyanate (IPDI) was heated under nitrogen to a temperature of 100° C. 600 g of polyether polyol Desmophen 1110 BD (Mn of 1002 g / mol) was added to the mixture via a dropping funnel over 6 hours. The mixture was stirred until the NCO content indicated complete conversion. The excess IPDI was subsequently removed by thin film evaporation at a temperature of 180° C. and a pressure of 0.02 mbar. The resulting product was a yellow, transparent NCO-terminated prepolymer with the following analytical characteristics: A content of 1.6% by weight of oligomers having a number average molecular weight of less than or equal to 1000 g / mol, based on the total solids content of the NCO-terminated prepolymer. Mn 2073g / mol NCO content 4.9% Polydispersity 1.28 Viscosity (23℃) 12300mPas Residual monomer 0.05%

[0130] Example 5 (Comparison) 300 g of hexamethylene diisocyanate (HDI) were heated to a temperature of 100° C. under nitrogen. 277 g of polyether polyol Desmophen 1110 BD (Mn of 1002 g / mol) were added to the mixture via a dropping funnel over 6 hours. The mixture was stirred until the NCO content indicated complete conversion. The excess HDI was subsequently removed by thin film evaporation at a temperature of 115° C. and a pressure of 0.03 mbar. The resulting product was a colorless, transparent NCO-terminated prepolymer with the following analytical characteristics: 1.0% by weight of oligomers having a number average molecular weight of less than or equal to 1000 g / mol, based on the total solids content of the NCO-terminated prepolymer. Mn 2772g / mol NCO content 4.4% Polydispersity 1.43 Viscosity (23℃) 2080mPas Residual monomer 0.02%

[0131] Example 6 (Comparative Example, Example 2 according to WO2016 / 116376) 1260 g of hexamethylene diisocyanate (HDI) were introduced under dry nitrogen with stirring at a temperature of 100° C. and 215 g of polyester polyol 2 were added over a period of 90 minutes. After the addition was complete, the reaction mixture was further stirred at 110° C. until an NCO content of 39.8%, corresponding to complete urethanization, was reached after about 3 hours. The unconverted monomeric HDI was removed on a thin-film evaporator at a temperature of 130° C. and a pressure of 0.1 mbar. This gave 382 g of a clear, colorless prepolymer having the following characteristics: A content of 28.0% by weight of oligomers having a number average molecular weight of less than or equal to 1000 g / mol, based on the total solids content of the NCO-terminated prepolymer. Mn 1163g / mol NCO content 10.7% Polydispersity 1.5 Viscosity (23℃) 3220mPas Residual monomer 0.03%

[0132] Example 7 (Comparative Example, Example 3 according to WO2016 / 116376) 1260 g of hexamethylene diisocyanate (HDI) were introduced under dry nitrogen with stirring at a temperature of 100° C. and 325 g of polyester polyol 3 were added over a period of 90 minutes. After the addition was complete, the reaction mixture was further stirred at 110° C. until an NCO content of 37.1%, corresponding to complete urethanization, was reached after about 3 hours.

[0133] The unconverted monomeric HDI was removed on a thin-film evaporator at a temperature of 130° C. and a pressure of 0.1 mbar. This gave 480 g of initially colorless, transparent prepolymer, which was cloudy and solidified after a few hours at room temperature. The semi-crystalline product had the following properties: A content of 7.1% by weight of oligomers having a number average molecular weight of less than or equal to 1000 g / mol, based on the total solids content of the NCO-terminated prepolymer. Mn 1599g / mol NCO content 8.3% Polydispersity 1.2 Viscosity (23℃) 1810mPas Residual monomer 0.02%

[0134] Application test: BYK 310 silicone-containing surface additive from BYK-Chemie GmbH (Germany) Dibutyltin dilaurate (DBTL), ADDOCAT® 201, Lanxess Deutschland GmbH, Germany Setalux® DA 665 BA acrylic polyol, OH content 4.6%, Allnex, Germany Desmophen® 650 MPA branched, hydroxyl-containing polyester, OH content 5.3%, Covestro Deutschland AG, Germany Desmophen® 2488 branched polyester polyol, OH content 16%, Covestro Deutschland AG, Germany Setalux® DA 870 acrylic polyol, OH content 4.2%, Allnex, Germany Anhydrous 1-methoxypropyl-2-acetate (MPA) was obtained from Azelis, Germany. Toluene was obtained from Azelis, Germany.

[0135] Component A: The polyols listed are combined with 0.1% Byk 310 and 0.03% catalyst DBTL and diluted with MPA.

[0136] Component B: NCO-terminated prepolymers of Examples 1-7. Formulation: Components A and B are combined in a 1:1 ratio to give a final solids content of 50%. The mixture is stirred by hand and then applied to the substrate. For glass plate application, the formulation is applied using a coating knife. The dry coating thickness is approximately 50 μm. The coating is then cured at 60° C. for 30 minutes. The coated glass plate is used for chemical testing and pendulum hardness experiments. Visual observations of the coating are also recorded.

[0137] Pendulum hardness: The pendulum damping according to Koenig was measured on a glass plate in accordance with DIN EN ISO 1522:2007-04 and is reported in Table 1 in seconds.

[0138] To test the coatings for solvent resistance, a small amount of each of the solvents xylene, 1-methoxypropyl-2-acetate, ethyl acetate and acetone was placed in a test tube and a cotton wool pad was placed at the opening to create a solvent-saturated atmosphere in the test tube. The test tube was then brought to the surface of the coating on the glass plate with the cotton pad and held there for 1 or 5 minutes. After wiping off the solvent, the film was examined and rated for destruction / softening / loss of adhesion (0: no change, 5: film completely dissolved). The five ratings reported in Table 1 are for four solvents in the order xylene (Xy), 1-methoxypropyl-2-acetate (MPA), ethyl acetate (EA) and acetone (Ac), indicated by four consecutive numbers. These were measured according to DIN EN ISO 4628-1:2016-07.

[0139] Table 1: Coating formulation overview and measured properties [Table 1] *For these examples, after 5 minutes the film is completely dissolved, therefore the values ​​given are determined after 1 minute of testing.

[0140] Discussion of the results in Table 1: As can be seen from the results, the NCO-terminated prepolymers of the invention make it possible to obtain coatings from formulations containing standard commercially available polyols. In contrast, the comparative formulations do not dry and result in sticky and soft coatings with insufficient hardness and limited solvent resistance.

Claims

1. General formula (I) 【Chemistry 1】 [In the formula, P, Q, and p are defined as follows] P independently comprises at least one organic radical obtained by removing a hydroxyl group from a polyol unit having an average molecular weight of 800 g / mol or more and 3000 g / mol or less and an OH functional value greater than 2 to less than 3. Q. Each independently, at least one aliphatic and / or cyclic aliphatic radical obtained by removing an isocyanate group from a diisocyanate, and p, each independently, is a number greater than or equal to 2.0, and Here, the NCO-terminated prepolymer is Based on the total solids content of the NCO-terminated prepolymer, the NCO content is 6.5% by weight or more and 12.0% by weight or less, and Based on the total solids content of the NCO-terminated prepolymer, the content of oligomers having a number average molecular weight of 1000 g / mol or less is 17% by weight or less, and Based on the total solids content of the NCO-terminated prepolymer, the monomer diisocyanate content is less than 0.5% by weight, and 2.0 or higher polydispersity [Having] NCO-terminated prepolymers for coating applications.

2. The NCO-terminated prepolymer according to claim 1, characterized in that the content of oligomers having a number average molecular weight of 1000 g / mol or less is 0.5% by weight or more to 17% by weight or less, preferably 1.0% by weight or more to 14% by weight or less, and most preferably 1.5% by weight or more to 10% by weight or less, based on the total solids content of the NCO-terminated prepolymer.

3. The NCO-terminated prepolymer according to claim 1, characterized in that the NCO-terminated prepolymer has an NCO content of 7.5% by weight or more and 11.0% by weight or less.

4. The NCO-terminated prepolymer according to claim 1, characterized in that the NCO-terminated prepolymer has a number average molecular weight Mn of 1700 g / mol or more, preferably 1700 g / mol or more to 3500 g / mol or less, and more preferably 1700 g / mol or more to 3100 g / mol or less.

5. The NCO-terminated prepolymer according to claim 1, characterized in that the NCO-terminated prepolymer has an average NCO functional value greater than 2.0, preferably greater than 2.

7.

6. The NCO-terminated prepolymer according to claim 1, wherein Q in general formula (I) is independently at least one aliphatic and / or cyclic aliphatic radical obtained by removing an isocyanate group from a diisocyanate, and is selected from the group consisting of 1,5-diisocyanatopentane, 1,6-diisocyanatohexane, isophorone diisocyanate, 2,4'- and 4,4'-diisocyanatodicyclohexylmethane, 1,3- and 1,4-bis-isocyanatomethylcyclohexane, 1,3- and 1,4-xylylene diisocyanate and mixtures selected from the above, preferably selected from the group consisting of 1,5-diisocyanatopentane, 1,6-diisocyanatohexane and / or isophorone diisocyanate.

7. The NCO-terminated prepolymer according to claim 1, characterized in that P in general formula (I) is independently at least one polyol unit having an average molecular weight of 900 g / mol or more and 2000 g / mol or less and an OH functional value greater than 2 and less than 3, more preferably an average molecular weight of 900 g / mol or more and 1500 g / mol or less and an OH functional value greater than 2 and less than 3.

8. The NCO-terminated prepolymer according to claim 1, characterized in that each p in general formula (I) is independently a number between 2 and less than 4.5, preferably greater than 2 and less than 3.

9. A method for preparing an NCO-terminated prepolymer according to any one of claims 1 to 8, comprising the following steps: a) Adding at least one polyol having a hydroxyl group functional value of 2 or more but less than 3 and polydispersity of 1.5 or more to a heated excess of at least one monomer diisocyanate, b) A step of removing excess monomer diisocyanate by distillation to reduce it to less than 0.5% by weight, preferably less than 0.3% by weight, and more preferably less than 0.1% by weight, based on the total solids content of the NCO-terminated prepolymer, to obtain an NCO-terminated prepolymer, and c) The method comprising optionally adding at least one solvent that is inert to the isocyanate group.

10. The method according to claim 9, characterized in that at least one polyol has an average molecular weight of 800 g / mol or more and 3000 g / mol or less, preferably 900 g / mol or more and 2000 g / mol or less, and more preferably 900 g / mol or more and 1500 g / mol or less.

11. Use of the NCO-terminated prepolymer according to any one of claims 1 to 8 in a curable composition for coatings, adhesives and / or sealants.

12. A two-component system comprising: component A) comprising at least one NCO-terminated prepolymer as described in any one of claims 1 to 8; and component B) comprising at least one compound comprising at least one tserevichnov active group.

13. The two-component system according to claim 12, characterized in that component B) contains less than 5% by weight, preferably less than 2% by weight, and more preferably less than 1% by weight of an organic solvent.

14. A method for curing a composition on a substrate, comprising the following steps i) A step of coating at least one two-component system according to claim 12 onto at least one substrate; and ii) A step of curing the deposited cured composition by exposing it to a temperature of 0 to 120°C, preferably 20 to 90°C, more preferably 20 to 60°C. The method, including the method described above.

15. A cured article that can be obtained, or is obtained, preferably directly, by the method of claim 14.

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