Isocyanate-terminated prepolymers for coating applications

Abstract

The present application relates to an isocyanate-terminated prepolymer obtained by reaction of (I) at least one polyol with (II) a stoichiometric excess of at least one monomeric diisocyanate, wherein the isocyanate-terminated prepolymer has i. a functional group equivalent weight FGEW equal to or greater than 560 g / mol, ii. a content of residual unreacted monomeric diisocyanate less than 0.2% by weight.

Description

[Technical field]

[0001] The present invention relates to isocyanate-terminated prepolymers, a method for producing the isocyanate-terminated prepolymers, and uses of the isocyanate-terminated prepolymers, for example for coating applications. The present invention further relates to a two-component system comprising component A) which comprises at least an isocyanate-terminated prepolymer and component B) which comprises at least one compound which comprises at least one Zerewitinoff active group. [Background technology]

[0002] It is known that isocyanate-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. The coating system can be used, for example, in the coating process of an original equipment manufacturer (OEM), or in manual coating applications in the refinishing field.

[0003] One problem, particularly in manual applications using isocyanate-terminated prepolymers, e.g. in the refinishing field, is that care must be taken to ensure that the coater is not exposed to the isocyanate-terminated prepolymers, as these can cause skin sensitization, e.g., they can cause allergic skin reactions. Thus, to remedy such skin sensitization problems, expensive handling systems and / or protective measures must be used during use of the prepolymers.

[0004] Skin sensitization data for commercial products are available from the Safety Data Sheets (SDS) that accompany each product. SDSs that comply with the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) are preferred. Some isocyanate-terminated prepolymers can cause allergic reactions with the skin upon contact with them, and therefore the SDSs for isocyanate-terminated prepolymers have H317 as a GHS hazard label. Summary of the Invention [Problem to be solved by the invention]

[0005] It is an object of the present invention to provide isocyanate-terminated prepolymers that have reduced or no skin sensitization potential.

[0006] Here, an isocyanate-terminated prepolymer having no skin sensitization potential refers to a compound that is evaluated to have an average reduction rate of lysine of 1.00% or less in a modified peptide binding assay (DPRA).

[0007] The peptide binding affinity test (DPRA) is designed to mimic the covalent binding of electrophilic chemicals to nucleophilic centers in skin proteins by quantifying the reactivity of chemicals to model synthetic peptides containing either cysteine ​​or lysine. The inventors surprisingly found a correlation between a negative local lymph node assay (LLNA) and a lysine depletion rate of 1.00% or less in the DPRA test, and thus a lysine depletion rate of 1.00% or less in the DPRA test reflects non-skin sensitization. In the present invention, the peptide depletion rate in the DPRA is performed using lysine as the peptide. The lysine % depletion value is used herein to classify a substance as a potential skin sensitizer or non-skin sensitizer. [Means for solving the problem]

[0008] The objective is surprisingly (I) a stoichiometric excess of at least one polyol (II) with at least one monomeric diisocyanate An isocyanate-terminated prepolymer obtained or obtainable by reaction wherein the isocyanate-terminated prepolymer is i. has a functional group equivalent weight (FGEW) of 560 g / mol or more; ii. having a residual unreacted monomeric diisocyanate content of less than 0.2% by weight, based on the total solids content of the isocyanate-terminated prepolymer; This was accomplished by providing an isocyanate-terminated prepolymer.

[0009] The advantage of the isocyanate-terminated prepolymers according to the invention is that the work safety of workers who use the isocyanate-terminated prepolymers according to the invention is improved. Furthermore, safety signs and related risk phrases may be less stringent compared to isocyanate-terminated prepolymers not according to the invention, with the result that the safety measures and protection regulations for using the isocyanate-terminated prepolymers according to the invention are less stringent. Considering the reduced skin sensitization of the NCO-terminated prepolymers according to the invention, these prepolymers can be advantageously used in manual applications, such as manual coating applications, or in foaming agents or sealants in the building industry.

[0010] The prepolymer containing free isocyanate groups is obtained or can be obtained by reacting at least one polyol with at least one monomeric diisocyanate, where the at least one monomeric diisocyanate is used in an amount such that the NCO groups are present in molar excess relative to the hydroxyl groups of the at least one polyol in order to obtain a prepolymer containing free isocyanate groups.

[0011] As used herein, "NCO" refers to the isocyanate group -N=C=O. As used herein, "NCO- or isocyanate-terminated" refers to a prepolymer containing at least one free NCO group at one of its termini.

[0012] In this specification, the term "functional group equivalent weight (FGEW)" refers to the number average molecular weight per isocyanate functional group, and is the number average molecular weight (M n ) divided by the average number of isocyanate groups per molecule (NCO functionality).

[0013] The isocyanate-terminated prepolymer has a functional group equivalent FGEW of 560 g / mol or more, preferably 600 g / mol or more, more preferably 650 g / mol or more, more preferably 700 g / mol or more, even more preferably 800 g / mol or more, even more preferably 1000 g / mol or more. This has the advantage that the work safety of the worker using the isocyanate-terminated prepolymer according to the present invention is further improved. From the viewpoint of skin sensitization, there is no preferred upper limit of FGEW. Considering the applicability in, for example, coating, adhesive, foam or sealant applications, the isocyanate-terminated prepolymer preferably has a functional group equivalent FGEW of 10000 g / mol or less, preferably 4000 g / mol or less, more preferably 2000 g / mol or less.

[0014] The isocyanate-terminated prepolymers according to the invention have a content of residual unreacted monomeric diisocyanates of less than 0.2% by weight, preferably less than 0.1% by weight, based on the total solids content of the isocyanate-terminated prepolymer, which has the advantage that the work safety of workers using the isocyanate-terminated prepolymers according to the invention is further improved.

[0015] The isocyanate-terminated prepolymer of the present invention has a number average molecular weight M of preferably 1100 to 160000 g / mol, preferably 1100 to 64000 g / mol, more preferably 1100 to 32000 g / mol.n has.

[0016] According to the present invention, unless otherwise stated, the average molecular weight is the number average molecular weight M n The molecular weight of a polymer is defined as the number average molecular weight M n applies. M n is determined by gel permeation chromatography (GPC) at 23 °C in tetrahydrofuran as solvent. The measurement is carried out as described in DIN 55672-1 (the version of DIN used was the version 03-2016): "Gel permeations chromatographie, Teil 1-Tetrahydrofuran als Elutionsmittel" (SECurity GPC-system from PSS Polymer Service, flow rate 1.0 ml / min; column: 2 × PSS SDV linear M, 8 × 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 Teil 1 mentioned above.

[0017] The isocyanate-terminated prepolymers according to the invention preferably have a content of less than or equal to 15% by weight of oligomers with 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.

[0018] The isocyanate-terminated prepolymer contains urethane and / or allophanate groups, and may optionally contain functional groups selected from the group consisting of urea groups, biuret groups, uretdione groups, carbodiimide groups, uretonimine groups, isocyanurate groups, and any combination thereof.

[0019] The isocyanate-terminated prepolymer according to the present invention preferably comprises (I) at least one polyol, and (II) at least one monomeric diisocyanate is the reaction product of Here, the at least one monomeric diisocyanate and the at least one polyol are used in amounts such that the NCO / OH equivalent ratio is from 1.5:1 to 25:1, preferably from 2:1 to 20:1.

[0020] The at least one polyol contains one or more hydroxyl groups per molecule and can be any suitable polyol for obtaining an isocyanate-terminated prepolymer according to the present invention. The at least one polyol may comprise an individual polyol or a mixture of two or more polyols.

[0021] At least one polyol preferably has an average number average molecular weight M of 60 to 20000 g / mol, preferably 60 to 8000 g / mol, more preferably 60 to 4000 g / mol. n When one individual polyol is applied, the individual polyol preferably has a number average molecular weight M of 60 to 20000 g / mol, preferably 60 to 8000 g / mol, more preferably 60 to 4000 g / mol. n When a mixture of two or more polyols is applied, the mixture of polyols preferably has a number average molecular weight M of 60 to 20000 g / mol, preferably 60 to 8000 g / mol, more preferably 60 to 4000 g / mol. n has.

[0022] At least one polyol preferably has an average OH functionality of 2 to 8, preferably 2 to 6, more preferably 2 to 4. If one individual polyol is applied, the individual polyol preferably has an OH functionality of 2 to 8, preferably 2 to 6, more preferably 2 to 4. If a mixture of two or more polyols is applied, the mixture of polyols preferably has an average OH functionality of 2 to 8, preferably 2 to 6, more preferably 2 to 4. The concept of OH functionality is well known to those skilled in the art. It indicates the number of OH groups (hydroxyl groups) present on average per molecule. Pure diols have an OH functionality of 2.0. The OH functionality of a polyol is given by the polyol supplier and can be determined by the functionality of the components used to prepare the polyol.

[0023] The at least one polyol is preferably selected from the group consisting of polyester polyols, polyether polyols, polyether polyester polyols, polycarbonate polyols, polyether polycarbonate polyols, polyether polyester polycarbonate polyols and mixtures thereof. In principle, these polyols are known to those skilled in the art.

[0024] The polyester polyols are obtained in a manner known per se by reacting a polyhydric alcohol, for example a polyhydric alcohol having 2 to 14 carbon atoms, with a substoichiometric amount of a polycarboxylic acid, the corresponding carboxylic acid anhydride, the corresponding polycarboxylic acid anhydride lower alcohol or a lactone.

[0025] The acids or acid derivatives used in the preparation of the polyester polyols may be aliphatic, cycloaliphatic and / or aromatic, may be optionally substituted, for example by halogen atoms, and / or may be 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.

[0026] Any desired mixtures of these starting compounds mentioned by way of example can also be used for the preparation of the polyester polyols.

[0027] Preferred polyester polyols are polycaprolactone polyols.

[0028] Suitable polyhydroxyl compounds of the polycarbonate type are polycarbonate polyols known per se and can be prepared, for example, by reacting dihydric alcohols having a molecular weight range of 62 to 400 g / mol with diaryl carbonates, for example diphenyl carbonate, dialkyl carbonates, for example dimethyl carbonate, or phosgene.

[0029] Suitable polyether polyols are in particular those obtainable 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 simple polyhydric alcohols having 2 to 14 carbon atoms. Aliphatic and / or aromatic amines are also suitable starter molecules. 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.

[0030] Suitable polyether polyols are also the polyoxytetramethylene glycols which are known per se by polymerization of tetrahydrofuran.

[0031] Suitable polyether polyester polyols are, for example, those obtained by addition of an epoxy to the esterification product of an aromatic dicarboxylic acid derivative and a difunctional or higher functional alcohol.

[0032] The at least one polyol is preferably selected from the group consisting of polyester polyols, polyether polyols, and mixtures thereof. The at least one monomeric diisocyanate can be any suitable diisocyanate, meaning that any compound containing two isocyanate groups is within the scope of the present invention. Aliphatic, cycloaliphatic or aromatic diisocyanates can in principle be used. Examples of aromatic diisocyanates are toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, polymeric or oligomeric diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, and mixtures thereof. Aliphatic and cycloaliphatic diisocyanates and mixtures thereof are preferred.

[0033] The at least one monomeric diisocyanate is preferably an aliphatic diisocyanate and / or a cycloaliphatic diisocyanate. Thus, the isocyanate-terminated prepolymer is preferably (I) a stoichiometric excess of at least one polyol (II) with at least one monomeric aliphatic diisocyanate and / or at least one monomeric cycloaliphatic diisocyanate It is obtained or obtainable by reaction.

[0034] Aliphatic diisocyanates are compounds in which two isocyanate groups are directly bonded to an aliphatic hydrocarbon group, whether or not aromatic groups are present in the compound. The term "aliphatic hydrocarbon group" refers to optionally branched alkyl, alkenyl and alkynyl groups. Alicyclic diisocyanates are compounds in which one or more isocyanate groups are directly bonded to an alicyclic hydrocarbon group, whether or not aromatic groups are present in the compound. The term "alicyclic hydrocarbon group" refers to cycloalkyl and cycloalkenyl groups that may be substituted with at least one aliphatic hydrocarbon group.

[0035] The aliphatic diisocyanate is preferably selected from the group consisting of 1,5-diisocyanatopentane, 1,6-diisocyanatohexane, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 1,3-xylylene diisocyanate, 1,3-tetramethylxylene diisocyanate, and mixtures thereof. More preferably, the aliphatic diisocyanate is selected from the group consisting of 1,5-diisocyanatopentane, 1,6-diisocyanatohexane, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and mixtures thereof.

[0036] The alicyclic diisocyanate is preferably isophorone diisocyanate (IPDI), 1-isocyanato-4-[(4-isocyanatocyclohexyl)methyl]cyclohexane (H 12 MDI), 1,3-bis(isocyanatomethyl)cyclohexane, and mixtures thereof.

[0037] More preferably, the diisocyanate is selected from the group consisting of 1,5-diisocyanatopentane, 1,6-diisocyanatohexane, isophorone diisocyanate, and mixtures thereof.

[0038] In principle, although this is not necessary, the NCO-terminated prepolymers of the invention can be diluted with solvents which are inert towards the isocyanate groups and preferably also towards other reactive groups of the starting components. 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 those commercially available under the names Solventnaphtha, Solvesso®, Isopar®, Nappar®, Varsol® (ExxonMobil Chemical Central Europe, Cologne, Germany) and Shellsol® (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 mixture of such solvents.

[0039] The present invention further comprises the steps of: a) mixing at least one polyol with an excess of at least one monomeric diisocyanate at a temperature suitable to form urethane groups; b) optionally, partial or complete allophanatization of the urethane groups by further reaction with at least one monomeric diisocyanate, which may be different from (a), optionally in the presence of a catalyst; c) removing excess monomeric diisocyanate, if present, by distillation down to less than 0.2 wt. %, preferably less than 0.1 wt. %, based on the total solids content of the NCO-terminated prepolymer to obtain an isocyanate-terminated prepolymer; and d) optionally adding at least one solvent which is inert towards isocyanate groups. The present invention relates to a process for preparing the NCO-terminated prepolymer of the present invention, comprising:

[0040] Preferably, the method of the present invention comprises the following steps: a) mixing at least one polyol with an excess of at least one monomeric diisocyanate; b) partial or complete allophanatization of the urethane groups by further reaction with at least one monomeric diisocyanate, which may be different from (a); c) removing excess monomeric diisocyanates, if present, by distillation down to less than 0.2% by weight, preferably less than 0.1% by weight, based on the NCO-terminated prepolymer, to obtain an isocyanate-terminated prepolymer; and d) optionally adding at least one solvent which is inert towards isocyanate groups. Includes.

[0041] The at least one monomeric diisocyanate is preferably reacted with the at least one polyol at a temperature of 20 to 200° C., preferably 40 to 160° C., more preferably 60 to 140° C. Preferably, in step a) the at least one polyol is added to a heated excess of the at least one monomeric diisocyanate.

[0042] The process of the present invention can be carried out without catalysis. However, if necessary, a suitable catalyst can be used to promote the urethanization reaction and, if present, the allophanatization reaction. When (cyclo)aliphatic diisocyanates are used, step b) is preferably carried out in the presence of a catalyst.

[0043] Suitable catalysts for accelerating the urethanization reaction 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, Amines, 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-ethyldiethanolamine, 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, metals in the normal oxidation state, such as iron(II) chloride, iron(III) chloride, bismuth(III), bismuth(II) 2-ethylhexanoate. I), bismuth(III) octanoate, bismuth(III) neodecanoate, zinc chloride, zinc(II) 2-ethylcaproate, tin(II) octanoate, tin(II) ethylcaproate, tin(II) palmitate, dibutyltin(IV) dilaurate (DBTL), dibutyltin(IV) dichloride or lead octanoate; amidines such as 2,3-dimethyl-3,4,5,6-tetrahydropyrimidine; tetraalkylammonium hydroxides such as tetramethylammonium hydroxide; alkali metal hydroxides such as sodium hydroxide, and alkali metal alkoxides such as 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. Suitable catalysts for promoting the allophanatization reaction are known in the art, for example based on Zn or Zr, for example zirconium octanoate or zinc(II) ethylhexanoate.

[0044] 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.

[0045] 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 an NCO content theoretically corresponding to complete conversion of isocyanate and hydroxyl groups in the reaction mixture, any urethanization catalyst used is preferably deactivated by addition of a suitable catalyst poison.

[0046] 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 p-toluenesulfonate 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.

[0047] The amount of catalyst poison required to deactivate the catalyst is guided by the amount of catalyst used. In general, an equivalent amount of catalyst poison is used based on the amount of urethanization catalyst used at the beginning. However, when the catalyst loss occurring during the reaction is taken into account, even 20-80 equivalent % of catalyst poison, based on the amount of catalyst initially used, may be enough to stop the reaction.

[0048] The process of the 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, conventional paint solvents known per se, such as 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 Solventnaphtha, Solvesso®, Isopar®, Nappar®, Varsol® (ExxonMobil Chemical Central Europe, Cologne, Germany) and Shellsol® (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 acetate, N-methylpyrrolidone and N-methylcaprolactam, or any desired mixtures of such solvents.

[0049] Independently of the optional use of a solvent in step a) or b), the method of the present invention comprises an optional step d) of adding at least one solvent inert towards isocyanate groups so as to reach a preferred viscosity of less than 2000 mPas at 23° C., measured according to DIN EN ISO 3219:1994-10. Such optional solvent is preferably selected from the list above. When step d) 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.

[0050] The NCO-terminated prepolymers of the present invention are particularly suitable for use in curable compositions for coatings, adhesives, sealants and / or foam systems, which are further aspects of the present invention. Since the NCO-terminated prepolymers of the present invention have reduced or no skin sensitization, the NCO-terminated prepolymers can be very advantageously applied to reduce and / or avoid any concerns of skin sensitization effects for people who may be exposed to said isocyanate-terminated prepolymers. Thus, the NCO-terminated prepolymers of the present invention can be very advantageously applied in particular to curable compositions for coatings, adhesives, sealants and / or foam systems that are applied manually. All the embodiments described or preferred for one subject of the present invention, such as the NCO-terminated prepolymers of the present invention, can also be freely combined with the embodiments described or preferred for other subject of the present invention, such as the subject of the use of the present invention, unless an obvious contrary indication is given. The present invention further relates to the use of an average depletion value of lysine in a modified peptide binding assay (DPRA) to determine the skin sensitization potential of isocyanate-terminated prepolymers, preferably an average depletion value of lysine of 1.00% or less in the assay reflects reduced or no skin sensitization potential.

[0051] A preferred coating system is a refinish coating system, especially an automotive refinish coating system.

[0052] The sealant and / or foam system is very suitably applicable in the building industry, for example for insulation purposes and / or for filling cavities.

[0053] The present invention further relates to coating, adhesive, sealant or foam systems, especially for manual application, which comprise the isocyanate-terminated prepolymers of the present invention.

[0054] The present invention further relates to a moisture-curing one-component system comprising at least one isocyanate-terminated prepolymer according to the present invention, in particular a moisture-curing one-component coating, adhesive, sealant or foam system comprising at least one isocyanate-terminated prepolymer according to the present invention, more particularly a one-component foam system, in particular a one-component foam system for applications in the building industry, in particular for manual application in the building industry.

[0055] The present invention further relates to a two-component system comprising component A) which comprises at least one isocyanate-terminated prepolymer according to the invention and component B) which comprises at least one compound which comprises at least one Zerewitinoff-active group. The two-component system is in particular a two-component coating system, a two-component adhesive system, a two-component sealant system or a two-component foam system, in particular for manual application. In a preferred embodiment, the two-component system is a sealant system or adhesive system, in particular for manual application in the building industry. In another preferred embodiment, the two-component system is a refinish coating system, in particular an automotive refinish system.

[0056] 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.

[0057] 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 diisocyanates to crosslink.

[0058] 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.

[0059] Said component B) preferably contains less than 5% by weight, preferably less than 2% by weight, more preferably less than 1% by weight of solvent, which 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.

[0060] If appropriate, further auxiliaries and additives that are customary in the field of coatings, adhesives, sealants or foams can be added to the system.Examples of suitable auxiliaries and additives are leveling auxiliaries, color pigments, filler materials, matting agents, inorganic or organic pigments, light stabilizers, lacquer additives such as dispersants, leveling agents, thickeners, defoamers and other auxiliaries, adhesives, fungicides, bactericides, stabilizers or inhibitors and catalysts or emulsifiers.

[0061] The present invention further comprises the steps of: i) applying at least one moisture-curing one-component system of the present invention onto at least one substrate or into a cavity; and ii) exposing the deposited composition to a temperature of 0 to 120° C., preferably 20 to 90° C., more preferably 20 to 60° C., to cure the deposited composition. The present invention relates to a method for curing a moisture curable one-component system on a substrate or within a cavity, comprising:

[0062] The present invention further comprises the steps of: i. mixing components A) and B) of a two-component system to obtain a mixture immediately before applying the two-component system onto at least one substrate or into a cavity; ii. applying the mixture onto at least one substrate or into a cavity; and iii. exposing the deposited composition to a temperature of 0-120° C., preferably 20-90° C., more preferably 20-60° C., to cure the deposited composition. The present invention relates to a method for curing a two-component system on a substrate or within a cavity, comprising:

[0063] When the deposited composition is cured, the cured composition forms a solid on the substrate or in the cavity. When the system is deposited on at least one substrate, such a solid is preferably a coating or an adhesive. When it is an adhesive, it is preferred to add a second substrate in a further step between step i. and step ii. or between step ii. and step iii, or to add such a second substrate directly in step i. or step ii. When the system is deposited in a cavity, such a solid is preferably a sealant or a foam.

[0064] Suitable substrates for the coatings, adhesives and / or sealants formulated using the NCO-terminated prepolymers of the invention or the moisture-curable one-component systems 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 can optionally be coated with a conventional primer prior to coating.

[0065] The present invention further relates to a cured article obtainable or obtained by the inventive method for curing a moisture-curable one- or two-component 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.

[0066] A further aspect of the present invention is the use of either the inventive NCO-terminated prepolymers or the inventive moisture-curing one-component systems or the inventive two-component systems for coatings, in particular in automotive refinishing applications, or for foams and / or sealants, in particular in the building industry.

[0067] The present invention relates in particular to the following embodiments: According to a first embodiment, the present invention provides a method for producing a method for manufacturing a semiconductor device comprising the steps of: (I) a stoichiometric excess of at least one polyol (II) with at least one monomeric diisocyanate Regarding the isocyanate-terminated prepolymer obtained by the reaction, Here, the isocyanate-terminated prepolymer is i. Functional group equivalent weight (FGEW) of 560 g / mol or more; ii. Residual unreacted monomeric diisocyanate content less than 0.2% by weight has.

[0068] According to a second embodiment, the present invention relates to an isocyanate-terminated prepolymer according to the first embodiment, wherein the isocyanate-terminated prepolymer has a functional group equivalent weight FGEW of 600 g / mol or more, preferably 650 g / mol or more, more preferably 700 g / mol or more, even more preferably 800 g / mol or more, even more preferably 1000 g / mol or more.

[0069] According to a third embodiment, the present invention relates to an isocyanate-terminated prepolymer according to the first or second embodiment, wherein the isocyanate-terminated prepolymer has a functional group equivalent weight FGEW of less than or equal to 10000 g / mol, preferably less than or equal to 4000 g / mol, more preferably less than or equal to 2000 g / mol.

[0070] According to a fourth embodiment, the present invention relates to an isocyanate-terminated prepolymer according to any one of the preceding embodiments, wherein the at least one polyol has an average number average molecular weight Mn of 60 to 20000 g / mol, preferably 60 to 8000 g / mol, more preferably 60 to 4000 g / mol.

[0071] According to a fifth embodiment, the present invention relates to an isocyanate-terminated prepolymer according to any one of the preceding embodiments, wherein the at least one polyol is selected from the group consisting of polyester polyols, polyether polyols, polyether polyester polyols, polycarbonate polyols, polyether polycarbonate polyols, polyether polyester polycarbonate polyols, and mixtures thereof.

[0072] According to a sixth embodiment, the present invention relates to an isocyanate-terminated prepolymer according to any one of the preceding embodiments, wherein the at least one polyol has an average OH functionality of 2 to 8, preferably 2 to 6, more preferably 2 to 4.

[0073] According to a seventh embodiment, the present invention relates to an isocyanate-terminated prepolymer according to any one of the preceding embodiments, wherein the isocyanate-terminated prepolymer has a content of monomeric diisocyanates of less than 0.1% by weight.

[0074] According to an eighth embodiment, the present invention relates to an isocyanate-terminated prepolymer according to any one of the preceding embodiments, wherein the isocyanate-terminated prepolymer contains urethane and / or allophanate groups, and optionally contains functional groups selected from the group consisting of urea groups, biuret groups, uretdione groups, carbodiimide groups, uretonimine groups, isocyanurate groups, and any combination thereof.

[0075] According to a ninth embodiment, the present invention relates to an isocyanate-terminated prepolymer according to any one of the preceding embodiments, wherein the isocyanate-terminated prepolymer comprises (I) at least one polyol, and (II) at least one monomeric diisocyanate wherein the at least one monomeric diisocyanate and the at least one polyol are used in amounts such that the NCO / OH equivalent ratio is from 1.5:1 to 25:1, preferably from 2:1 to 20:1.

[0076] According to a tenth embodiment, the present invention relates to an isocyanate-terminated prepolymer according to any one of the preceding embodiments, wherein at least one monomeric diisocyanate is an aliphatic and / or cycloaliphatic diisocyanate.

[0077] According to an eleventh embodiment, the present invention relates to an isocyanate-terminated prepolymer according to the tenth embodiment, wherein the aliphatic diisocyanate is selected from the group consisting of 1,5-diisocyanatopentane, 1,6-diisocyanatohexane, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and mixtures thereof.

[0078] According to a twelfth embodiment, the present invention relates to an isocyanate-terminated prepolymer according to the tenth or eleventh embodiment, wherein the cycloaliphatic diisocyanate is selected from the group consisting of isophorone diisocyanate, 1-isocyanato-4-[(4-isocyanatocyclohexyl)methyl]cyclohexane (H12MDI), 1,3-bis(isocyanatomethyl)cyclohexane, and mixtures thereof.

[0079] According to a thirteenth embodiment, the present invention relates to an isocyanate-terminated prepolymer according to any one of the preceding embodiments, wherein the diisocyanate is selected from the group consisting of 1,5-diisocyanatopentane, 1,6-diisocyanatohexane, isophorone diisocyanate, and mixtures thereof.

[0080] According to a fourteenth embodiment, the present invention relates to a method for producing a pharmaceutical composition comprising the steps of: a) mixing at least one polyol with an excess of at least one monomeric diisocyanate; b) optionally, partial or complete allophanatization of the urethane groups by further reaction with at least one monomeric diisocyanate, which may be different from (a), c) removing excess monomeric diisocyanates, if present, by distillation down to less than 0.2% by weight, preferably less than 0.1% by weight, based on the NCO-terminated prepolymer, to obtain an isocyanate-terminated prepolymer; and d) optionally adding at least one solvent which is inert towards isocyanate groups. The present invention relates to a method for preparing an isocyanate-terminated prepolymer according to any one of the preceding embodiments, comprising:

[0081] According to a fifteenth embodiment, the present invention relates to a method for producing a pharmaceutical composition comprising the steps of: a) mixing at least one polyol with an excess of at least one monomeric diisocyanate; b) partial or complete allophanatization of the urethane groups by further reaction with at least one monomeric diisocyanate, which may be different from (a); c) removing excess monomeric diisocyanates, if present, by distillation down to less than 0.2% by weight, preferably less than 0.1% by weight, based on the NCO-terminated prepolymer, to obtain an isocyanate-terminated prepolymer; and d) optionally adding at least one solvent which is inert towards isocyanate groups. The present invention relates to a method according to a fourteenth embodiment, comprising:

[0082] According to a sixteenth embodiment, the present invention relates to the use of an isocyanate-terminated prepolymer according to any one of the first to thirteenth embodiments or obtainable by the method according to the fourteenth or fifteenth embodiments as an isocyanate-terminated prepolymer having reduced or no skin sensitization.

[0083] According to a seventeenth embodiment, the present invention relates to the use of an isocyanate-terminated prepolymer according to any one of the first to thirteenth embodiments or obtainable by the method according to the fourteenth or fifteenth embodiments in a curable composition for a coating, adhesive, sealant and / or foam system, in particular for a manually applied system.

[0084] According to an eighteenth embodiment, the present invention relates to the use according to the seventeenth embodiment for reducing skin sensitization of coating, adhesive, sealant and / or foam systems, in particular for reducing skin sensitization of manually applied coating, adhesive, sealant and / or foam systems.

[0085] According to a nineteenth embodiment, the present invention relates to the use according to embodiment seventeen or eighteen, wherein the coating system is a refinish coating system, in particular an automotive refinish coating system.

[0086] According to a twentieth embodiment, the present invention relates to the use according to the seventeenth or eighteenth embodiment, wherein the curable composition is applied in a sealant and / or foam system, in particular a sealant and / or foam system applied in the building industry.

[0087] According to a twenty-first embodiment, the present invention relates to a coating, adhesive, sealant or foam system, in particular for manual application, comprising an isocyanate-terminated prepolymer obtainable by a process according to any one of the first to thirteenth embodiments or according to the fourteenth or fifteenth embodiment.

[0088] According to a twenty-second embodiment, the present invention relates to a two-component system comprising component A) which comprises at least one isocyanate-terminated prepolymer according to any one of embodiments 1 to 13 or obtained by the method according to embodiment 14 or 15, and component B) which comprises at least one compound which comprises at least one Zerewitinoff-active group.

[0089] According to a twenty-third embodiment, the present invention relates to a two-component system according to embodiment 22, characterized in that the two-component system is a coating system, a sealant system, a foam system or an adhesive system, in particular for manual application.

[0090] According to a twenty-fourth embodiment, the invention relates to the two-component system according to embodiment 22, characterized in that the two-component system is a refinish coating system, in particular an automotive refinish system.

[0091] According to a twenty-fifth embodiment, the present invention relates to a moisture-curing one-component system comprising at least one isocyanate-terminated prepolymer according to any one of the embodiments 1 to 13 or obtainable by a process according to the embodiment 14 or 15.

[0092] According to a twenty-sixth embodiment, the present invention relates to a moisture-curing one-component system according to embodiment twenty-five, wherein the one-component system is a one-component foam system, in particular a one-component foam system for applications in the building industry.

[0093] The present invention is illustrated with reference to examples which should not be construed as limiting. All percentages are by weight unless otherwise stated. EXAMPLES

[0094] Examples and Comparative Experiments Raw materials used Desmodur® H (monomer aliphatic diisocyanate), Covestro Germany. Desmodur® I (monomer aliphatic diisocyanate), Covestro Germany. Desmodur® 2460 MDI (monomer aromatic diisocyanate), Covestro Germany. Desmodur® T 80 (monomeric aromatic diisocyanate), Covestro Germany. 2-Ethylhexanol was obtained from Sigma Aldrich. · Octa-Soligen® Zirconium-18 (zirconium octoate) was obtained from Borchers. Zinc(II)-ethylhexanoate was obtained from abcr GmbH. Isophthalic acid chloride was obtained from Acros Organics. Dibutyl phosphate was obtained from Acros Organics.

[0095] Polyol types: Polyol 1 Polyether polyols based on propylene oxide and propylene glycol. OH functionality: F=2 M n = 200g / mol Polyol 2 Linear polyether polyols based on propylene oxide and propylene glycol. OH functionality: F=2 M n =431g / mol Polyol 3 Linear polyether polyols based on propylene oxide and propylene glycol. OH functionality: F=2 M n = 1000g / mol Polyol 4 A polyester polyol based on monoethylene glycol and phthalic anhydride. OH functionality: F=2 M n =390g / mol Polyol 5 Linear polyether polyols based on propylene oxide and propylene glycol. OH functionality: F=2 M n =2000g / mol Polyol 6 Diethylene glycol-based polycaprolactone from Ingevity OH functionality: F=2 M n =830g / mol Polyol 7 A linear polyester polyol based on adipic acid, phthalic anhydride, diethylene glycol and monoethylene glycol. Low molecular weight oligomers were removed by distillation at 195 °C and a pressure of 0.2-0.5 mbar. OH functionality: F=2 M n =571g / mol Polyol 8 A linear polyester polyol based on neopentyl glycol, monoethylene glycol and adipic acid. OH functionality: F=2 M n =500g / mol Polyol 9 A linear polyester polyol based on diethylene glycol, 1,4-butanediol, monoethylene glycol and adipic acid. OH functionality: F=2 M n =2120g / mol Polyol 10 Butanediol-based polycaprolactone from Ingevity OH functionality: F=2 M n = 400g / mol Polyol 11 A branched polyester based on trimethylolpropane, neopentyl glycol, 1,3-butanediol and isophthalic acid. Low molecular weight oligomers were removed by distillation at 195°C. OH functionality: F=3.4 M n =740g / mol Polyol 12 Trimethylolpropane-based polycaprolactone obtained from Ingevity. OH functionality: F=3 M n =2000g / mol Polyol 13 A branched polyether based on glycerol and propylene oxide. OH functionality: F=3 M n =714g / mol Polyol 14 Linear polyether polyols based on propylene glycol and propylene oxide. OH functionality: F=2 M n= 1000g / mol

[0096] method All percentages are by weight unless otherwise stated. The NCO content was determined by titration according to DIN EN ISO 11909:2007-05.

[0097] The residual diisocyanate monomer content was determined by gas chromatography with an internal standard in accordance with DIN EN ISO 10283:2007-11.

[0098] All viscosity measurements were performed using a Physica MCR 51 rheometer from Anton Paar Germany GmbH (Germany) according to DIN EN ISO 3219:1994-10 at a shear rate of 250 s-1.

[0099] The content of oligomers with a number average molecular weight of ≦1000 g / mol is 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 × PSS SDV linear M, 8 × 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.

[0100] Functional group equivalent weight (FGEW) refers to the number average molecular weight per isocyanate functional group, and is the number average molecular weight (M n) divided by the average number of isocyanate groups per molecule (NCO functionality).

[0101] The NCO functionality of the prepared urethane prepolymer is equal to the OH functionality of the polyol used as raw material.

[0102] The OH functionality of the polyol is provided by the polyol supplier and can be determined by the functionality of the components used to prepare the polyol.

[0103] NCO functionality F of the prepared allophanate prepolymer allophanate teeth, 13 Polyol functionality F in relation to the allophanate content of the respective prepolymers as determined by C NMR polyol It is calculated by:

[0104]

number

[0105] Analysis of the allophanate content of the prepared prepolymers showed that 13 C NMR of the allophanate moiety in CDCl3. 13 The C NMR shifts are found at δ1=153.8 ppm and δ2=155.7 ppm in a 1:1 ratio for 100% allophanate production. However, during the synthesis of allophanate, not all urethane groups are converted to allophanate moieties. Here, the content of allophanate in the prepolymer can be calculated by the ratio of the integrals of δ1 and δ2.

[0106] The modified peptide binding assay (modified DPRA assay) was performed according to OECD guideline 442C (OECD (2021), Test No. 442C: Chemical skin sensitization assay: Assays addressing adverse outcome pathway key events for covalent binding to proteins, OECD Chemicals Testing Guidelines Section 4, OECD Publishing, Paris, https: / / doi.org / 10.1787 / 9789264229709-en). Only lysine reduction was tested. This test determines the reduction rate of a synthetic peptide containing lysine due to reaction with a potential skin sensitizer. Lysine reduction in percent is the loss of lysine-containing peptides, as determined by HPLC / UV, compared to a control.

[0107] For the present invention, potential skin sensitizers are low-monomer isocyanate-terminated prepolymers or diisocyanates, which may be present in low-monomer isocyanate-terminated prepolymers as residual diisocyanates after thin film distillation.

[0108] The method "Local Lymph Node Assay" (LLNA) is specified in the EPA guideline OPPTS 870.2600, Skin Sensitization, March 2003; updated OECD TG 429 for the evaluation of skin sensitization, 2010.

[0109] A modified local lymph node assay (IMDS) will be performed on 24 female NMRI mice (6 animals / test article group and 6 control animals) to determine the specific (sensitizing) or non-specific (irritating) irritant potential of the test article, and a concurrent positive group of 6 animals treated with alpha-hexylcinnamaldehyde will be examined.

[0110] Modifications in the IMDS (Integrated Model for Differentiation of Skin reactions) compared to the classical LLNA refer to the measurement of cell proliferation by cell counting instead of radioactive labeling. In addition, acute inflammatory skin reactions (ear swelling I ear weight) are determined to distinguish between specific and nonspecific activation of immune-competent cells in the draining lymph nodes, as also recommended in the update of OECD TG 429.

[0111] Route of Administration and Dosage: The test substance in the formulation or the vehicle is applied epicutaneously to the dorsal part of both ears of the animals, and this treatment is repeated for three consecutive days (d1, d2 and d3). The dose is 25 μl / ear.

[0112] autopsy: The animals are anesthetized by carbon dioxide inhalation and sacrificed one day after the last application (day 4). The appropriate organs are then removed. The lymphatic organs (auricular lymph nodes) are transferred to physiological saline (PBS).

[0113] Calculation of metrics: Determination of weights and cell numbers is carried out by appropriate laboratory procedures. The so-called stimulation (or LLN-) index is calculated by dividing the weight or absolute number of cell numbers of lymph nodes treated with a substance by those treated with vehicle.

[0114] Before the first treatment and before sacrifice, the thickness of both ear pinnae of the animals is measured using a spring-loaded micrometer. The corresponding index is calculated by dividing the ear thickness of the substance-treated ear by the ear thickness of the vehicle-treated ear.

[0115] On the fourth day of the test, the ears of the sacrificed animals are weighed by taking a piece of each ear with a punch, 8 mm in diameter, and the corresponding index is calculated by dividing the weight of the ear treated with the substance by the weight of the ear treated with the vehicle.

[0116] A compound has a negative local lymph node assay (LLNA) if it has a stimulation index (SI value) of less than 3. Compounds with an SI value of less than 3 are considered negative for skin sensitization.

[0117] A correlation between a negative local lymph node assay (LLNA) and a negative modified peptide binding assay (DPRA) has been found, details of which are shown in Table 3.

[0118] Working Example Method for synthesizing urethane prepolymers A 5-15-fold excess of monomeric diisocyanates is heated to 70°C-100°C under nitrogen. The respective polyols, preheated to 60°C-80°C as required, are added continuously under stirring to the monomeric diisocyanates via a dropping funnel. The mixture is stirred at 70°C-100°C until the NCO content indicates complete urethanization. The excess monomeric diisocyanates are subsequently removed by thin-film evaporation at temperatures between 110°C-185°C and pressures between 0.2-0.5 mbar. The resulting products are NCO-terminated urethane prepolymers with analytical properties as listed in Tables 1a and 1b.

[0119] Method for synthesizing allophanate prepolymers A 5-15-fold excess of monomeric aliphatic or cycloaliphatic diisocyanate is heated to 100 °C under nitrogen. The respective polyol is preheated to 80 °C as required and added under stirring to the monomeric diisocyanate via a dropping funnel. The mixture is stirred at 100 °C until the NCO content indicates complete urethanization. To drive the allophanatization, 100 ppm of catalyst is added to the mixture as a 10 w% solution in 2-ethylhexanol. The mixture is stirred at 90 °C to 110 °C until the final NCO content is reached. Subsequently, an equimolar amount of a terminator is added as a 10 w% solution in 2-ethylhexanol. The excess monomeric diisocyanate is then removed by thin-film evaporation at temperatures of 115 °C to 120 °C and pressures of 0.2 to 0.5 mbar. The resulting product is an NCO-terminated allophanate prepolymer with analytical characteristics as listed in Table 2.

[0120] A modified peptide binding assay (DPRA) was performed with the prepolymers synthesized as described above. The average lysine reduction rates obtained are listed in Tables 1a, 1b and 2.

[0121] Table 1a: Comparative Experiments A-G: NCO-terminated urethane prepolymer [Table 1a] TIFF2025508155000003.tif209166

[0122] Table 1b: Examples 1 to 7: NCO-terminated urethane prepolymer [Table 1b] TIFF2025508155000005.tif204169

[0123] Comparative experiments A-G show an average lysine reduction rate of more than 1, leading to the conclusion that prepolymers with functional group equivalent weight (FGEW) less than 560 g / mol or prepolymers with a monomeric diisocyanate content of more than 0.2% (see comparative example G) independently of the FGEW cause an average lysine reduction rate of more than 1 in the modified peptide binding test described. Examples 1-7 of the invention with an FGEW of more than 560 g / mol and a monomeric diisocyanate content of less than 0.2% show an average lysine reduction rate of less than 1. Table 1b also shows that this behavior is independent of the type of diisocyanate used.

[0124] Table 2: Comparative Experiments HJ and Examples 8-10: NCO-Terminated Allophanate Prepolymers [Table 2]

[0125] Comparative experiments H-J show an average lysine reduction of more than 1, leading to the conclusion that prepolymers with a functional group equivalent weight (FGEW) of less than 560 g / mol cause an average lysine reduction of more than 1 in the described peptide binding test. Examples 8-10 of the invention, with an FGEW of more than 560 g / mol and a monomeric diisocyanate content of less than 0.2%, show an average lysine reduction of less than 1.

[0126] Table 3: Correlation of LLNA and DPRA results [Table 3]

[0127] Comparative experiments B, C and E show a lysine mean reduction rate of more than 1 and a positive LLNA result, leading to the conclusion that a correlation can be found between the positive results of both skin sensitization tests. Examples 4 to 7 of the present invention show a lysine mean reduction rate of less than or equal to 1 and a negative LLNA result, again showing a positive correlation between the negative results of both skin sensitization tests.

Claims

1. (I) A stoichiometric excess of at least one polyol (II) An isocyanate-terminated prepolymer obtained by reaction with at least one monomer diisocyanate, wherein the isocyanate-terminated prepolymer is i. Functional group equivalents of 560 g / mol or more FGEW, ii. The isocyanate-terminated prepolymer having a content of less than 0.2% by weight of residual unreacted monomer diisocyanate.

2. The isocyanate-terminated prepolymer according to claim 1, wherein the isocyanate-terminated prepolymer has a functional group equivalent FGEW of 600 g / mol or more.

3. The isocyanate-terminated prepolymer according to claim 1, wherein the isocyanate-terminated prepolymer has a functional group equivalent FGEW of 10,000 g / mol or less.

4. At least one polyol has an average number-average molecular weight M of 60 to 20,000 g / mol. ｎ The isocyanate-terminated prepolymer according to claim 1, having the following characteristics.

5. The isocyanate-terminated prepolymer according to claim 1, wherein the isocyanate-terminated prepolymer contains a urethane group and / or an allophanate group.

6. Isocyanate-terminated prepolymers (I) at least one polyol, and (II) A reaction product of at least one monomer diisocyanate, Here, at least one monomer diisocyanate and at least one polyol are used in amounts such that the NCO / OH equivalent ratio is 1.5:1 to 25:

1. The isocyanate-terminated prepolymer according to claim 1.

7. The isocyanate-terminated prepolymer according to claim 1, wherein at least one monomer diisocyanate is an aliphatic diisocyanate and / or an alicyclic diisocyanate.

8. The following steps: a) A step of mixing at least one polyol with an excess of at least one monomer diisocyanate, and c) If present, the process of removing excess monomer diisocyanate from the NCO-terminated prepolymer by distillation to reduce it to less than 0.2% by weight to obtain an isocyanate-terminated prepolymer. A method for preparing an isocyanate-terminated prepolymer according to any one of claims 1 to 7, comprising:

9. The following steps: a) A step of mixing at least one polyol with an excess of at least one monomer diisocyanate, b) A step of partially or completely allophanating the urethane group by further reaction with at least one monomer diisocyanate (which may be different from (a)), and c) If present, the process of removing excess monomer diisocyanate from the NCO-terminated prepolymer by distillation to reduce it to less than 0.2% by weight to obtain an isocyanate-terminated prepolymer. The method according to claim 8, including the method described in claim 8.

10. Use of the isocyanate-terminated prepolymer according to any one of claims 1 to 7 as an isocyanate-terminated prepolymer with reduced or no skin sensitization properties.

11. Use of an isocyanate-terminated prepolymer according to any one of claims 1 to 7 in a curable composition for coating systems, adhesive systems, sealant systems and / or foam systems.

12. The use according to claim 11 for reducing skin sensitization of coating systems, adhesive systems, sealant systems and / or foam systems.

13. A coating, adhesive, sealant, or foam system comprising an isocyanate-terminated prepolymer according to any one of claims 1 to 7.

14. A two-component system comprising: component A) comprising at least one isocyanate-terminated prepolymer as described in any one of claims 1 to 7; and component B) comprising at least one compound comprising at least one tserevichnov active group.

15. A moisture-curable one-component system comprising at least one isocyanate-terminated prepolymer as described in any one of claims 1 to 7.