EP3568423A1

EP3568423A1 - Low-solvent coating systems for textiles

Info

Publication number: EP3568423A1
Application number: EP18700873.5A
Authority: EP
Inventors: Jürgen Köcher; Rafael LANGER
Original assignee: Covestro Deutschland AG
Current assignee: Covestro Deutschland AG
Priority date: 2017-01-13
Filing date: 2018-01-10
Publication date: 2019-11-20
Also published as: US20190359850A1; WO2018130586A1; CN110382583A; JP2020506256A

Abstract

The invention relates to a coating composition for elastic coating of textile materials, containing at least one immobilized, isocyanate-terminated prepolymer (component A), wherein the isocyanate-terminated prepolymer is produced from a polyol component a) and from an araliphatic isocyanate component b), and the end-positioned isocyanate groups are blocked with N-alkyl benzylamines and/or partially with N-alkyl benzylamines and partially with 3,5-dimethyl pyrazole, at least one polyamine (component B) and < 30 wt%, based on the total mass the of coating composition of at least one organic solvent. The invention further relates to a method for coating substrates with the coating composition according to the invention, to the substrate which can be obtained thereby, and to the use of the coating composition according to the invention for producing elastic coatings or elastic films.

Description

Low-solvent coating systems for textiles

The present invention relates to a special, low-solvent coating composition for the elastic coating of textile materials comprising component A), at least one blocked, isocyanate-terminated prepolymer and component B) at least one polyamine. The invention further provides a process for coating substrates, in particular textiles, with the coating composition according to the invention, and the coated substrate obtainable thereby, and also the use of the coating composition according to the invention for the production of elastic coatings or elastic films. Low-solvent coating compositions for textiles based on polyurethane ureas are generally known and described, for example, in DE 2 902 090 A1. The coating systems comprise 2 constituents, a ketoxime-blocked polyisocyanate and a compound which has two amino groups which react with one another at temperatures above 120 ° C. At these temperatures, the ketoxime groups are split off and the NCO groups released and are available for reaction with the amine component. The described systems furthermore have good storage stability at ambient temperatures. From the coating compositions elastic films can be obtained which have good mechanical stability. In film formation, however, ketoximes, such as butanone oxime, are liberated. Butanonoxime is currently thought to be a substance hazardous to health. Currently, evaluations are being conducted on this substance to assess the toxicology of the substance. Depending on the outcome of these studies, there may be some changes in the use of this product in some areas, either through the requirement for additional control measures or the desire to substitute this product. Therefore, there is always a need for alternative, low-solvent coating compositions which are storage stable at ambient temperature and which do not release ketoximes when crosslinked or reacted and film-formed. However, the coatings obtained should nevertheless have the advantageous properties of the systems known in the art.

In DE 3434881 and EP 0787754 solid blocked polyisocyanates are described as curing agents for powder coatings, wherein, inter alia, aralkyl-substituted secondary amines such as tert-butylbenzylamine are mentioned as blocking agents. Such paints cure even at less than 170 ° C and show no tendency to discoloration even when baked, overburning or weathering. As blocking agents for polyisocyanates in thermosetting liquid paint applications, such amines, especially N-tert-butyl-N-benzylamine, described in the patents EP 1375550, EP 1375551 and EP 1375552. Dimethylpyrazoles are also known as blocking agents for polyisocyanates (D.A Wieks and Zeno W. Wieks, Jr., Progress in Organic Coatings 43 (2001), 131-140; DA Wieks and Zeno W. Wieks, Jr., Progress in Organic Coatings 36 (1987). 1999), 148 - 172).

The blocking agents described have not hitherto been used for producing elastic textile coatings. When blocking the known low-solvent coating compositions for textiles based on polyurethane ureas (for example, according to DE 2 902 090 A1), the problem arises that, in the case of an exchange of the blocking agent of ketoximes, for example tert-butylbenzylamine or 3,5 -Dimethylpyrazol not have sufficient storage stability at room temperature (Potlife or pot life) more. This means that after mixing the two components, the viscosity increases so fast that processing after a short time, in many cases within an hour, at room temperature is no longer possible.

It was therefore an object of the present invention to provide for textile coating suitable, low-solvent coating compositions which are storage stable at ambient temperature and do not release ketoximes in the coating process. In addition, the films obtained from corresponding coating compositions should have good elastic and mechanical properties.

This object is achieved according to the invention by a coating composition for the elastic coating of textile materials containing at least one blocked isocyanate-terminated prepolymer (component A), wherein the isocyanate-terminated prepolymer is prepared from a polyol component a) and an araliphatic isocyanate component b), and the terminal isocyanate groups are blocked with N-alkylbenzylamines or partially with N-alkylbenzylamines and in some cases with 3,5-dimethylpyrazole, at least one polyamine (component B) and <30% by weight, preferably <25% by weight , or preferably <20 wt .-%, based on the total mass of the coating composition, of at least one organic solvent.

The araliphatic isocyanate component b) preferably has at least two isocyanate groups. In the context of the invention, araliphatic isocyanate component b) is understood to mean that the isocyanate component b) has at least one aliphatic carbon atom and at least one aromatic hydrocarbon group. Preferably, at least one of the at least two terminal isocyanate groups of the araliphatic isocyanate component b) is bonded to an aliphatic carbon atom. Further preferably, at least two of the at least two isocyanate groups of the araliphatic isocyanate component b) are each bonded to an aliphatic carbon atom. Preferred polyisocyanates for the preparation of the prepolymer component A are those which have bound the isocyanate group to an aliphatic carbon atom, the isocyanate alkyl groups of which are preferably linked to one another via an aromatic radical. Preferred polyisocyanates of this type are tetramethylxylylene diisocyanate (m- and / or p-TMXDI). Particularly preferably, the prepolymers A contain xylylene diisocyanate (m- and / or p-XDI).

In a preferred embodiment of the coating composition, the terminal isocyanate groups of the isocyanate-terminated prepolymer are selected from the group consisting of m-tetramethylxylylene diisocyanate (m-TMXDI), p-tetramethylxylylene diisocyanate (p-TMXDI), m-xylylene diisocyanate (m-XDI), p-xylylene diisocyanate ( p-XDI) or a mixture of at least two thereof. The terminal isocyanate groups of the isocyanate-terminated prepolymer preferably consist of xylylene diisocyanate (m- and / or p-XDI).

It has surprisingly been found that the low-solvent coating compositions according to the invention are suitable for the coating of textiles and form elastic films with good mechanical properties without the release of ketotoxins. In particular, the coating compositions according to the invention also have a sufficiently long shelf life at room temperature prior to processing. This is not the case when prepolymers based purely on aromatic polyisocyanates or containing a high proportion of aromatic polyisocyanates are used.

The coating composition contains a blocked, isocyanate-terminated prepolymer (component A) wherein the isocyanate-terminated prepolymer is prepared from a polyol component a) and an isocyanate component b) and the terminal isocyanate groups with N-alkylbenzylamines or partially with N-alkyl benzylamines and partially blocked with 3,5-dimethylpyrazole.

The coating composition preferably contains from 30 to 95% by weight and more preferably from 50 to 95% by weight of component A), based on the total weight of the coating composition.

The polyol component a) used to prepare the prepolymer component A) preferably comprises at least one polyol preferably selected from the group consisting of polyether polyols, polyester polyols, polycarbonate polyols, polyether carbonate polyols and polyester carbonate polyols or a mixture of at least two thereof. The number average molecular weight M _{n of} the at least one polyol is preferably in a range from 300 to 8000 g / mol, or preferably in a range from 400 to 7000 g / mol, or preferably in a range from 500 to 6000 g / mol. Preferably, the at least one polyol has an average functionality of hydroxyl groups in a range of 1.5 to 4.0, or preferably in a range of 1.8 to 3.5, or preferably in a range of 2.0 to 3.0. The expression "polymeric" polyols, such as polyether polyols or polyester polyols, means here in particular that the polyols mentioned above have at least two, preferably at least three, interconnected repeat units of the same or alternating structural units Gel permeation chromatography (GPC) in tetrahydrofuran at 23 ° C. The procedure according to DIN 55672-1 is "gel permeation chromatography, Part 1 - tetrahydrofuran as eluent" (SECurity GPC system from PSS Polymer Service, flow rate 1.0 ml / min; : 2 * PSS SDV linear M, 8x300 mm, 5 μπι; RID detector) .The polystyrene samples of known molecular weight are used for the calibration.The calculation of the number-average molecular weight is software-based.basic points and evaluation limits are determined in accordance with DIN 55672 Part 1.

By varying the number average molecular weights and the functionality of the polyols, the properties of the resulting films, such as elasticity, moduli, melting temperature and water swelling can be influenced.

Compounds suitable as polyol component a) are preferably selected from the group consisting of bifunctional polypropylene oxide ethers based on bisphenol A, bifunctional polypropylene oxide ethers based on propylene glycol, trifunctional polyethers of propylene oxide and ethylene oxide based on glycerol or a mixture of at least two thereof. As a polyol component for the preparation of the polyurethane prepolymers, polyhydric polyether polyols known per se from polyurethane chemistry can be used which are obtainable in a manner known per se by alkoxylation of suitable starter molecules.

Suitable starter molecules are, for example, simple polyols such as ethylene glycol, 1,2- and 1,3-propylene glycol and 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 2-ethylhexanediol-1,3-glycerol, trimethylolpropane , Pentaerythritol, sorbitol and low molecular weight, hydroxyl-containing esters of such polyols with aliphatic or aromatic dicarboxylic acids, and low molecular weight ethoxylation or propoxylation of such simple polyols or any mixtures of at least two such modified or unmodified alcohols, water, organic polyamines having at least two NH bonds or any mixtures of at least two such starter molecules. Also suitable are aromatic hydroxy compounds such as bisphenol A. Suitable for the alkoxylation are cyclic ethers such as tetrahydrofuran and / or alkylene oxides such as ethylene oxide, propylene oxide, butylene oxides, styrene oxide or epichlorohydrin, in particular ethylene oxide and / or propylene oxide, in any order or can also be used in a mixture of at least two of them in the alkoxylation. Trade names of suitable polyether polyols made up of repeating propylene oxide and / or ethylene oxide units are, for example Desmophen ^® -, Acclaim ^® -, Arcol ^® -, Baycoll ^® -, Bayfill ^® -, Bayflex ^® - Baygal ^® -, PET ^® - and polyethers polyols of Covestro AG (such. as Desmophen 3600Z ^®, ^® Desmophen 1900U, Acclaim ^® polyol 2200 Acclaim ^® polyol 40001, Arcol ^® polyol 1004 Arcol ^® polyol 1010 Arcol ^® polyol 1030 Arcol polyol ^® 1070, Baycoll BD ^® 1110 Bayfill VPPU ^® 0789, Baygal ^® K55, PET ^® 1004 polyether ^® S180). Other suitable homo- polyethylene oxides are the BASF SE example Pluriol ^® E-marks suitable homo- Pol propylene oxides are, for example Pluriol ^® P brands from BASF SE, suitable mixed copolymers of ethylene oxide and propylene oxide such as the Pluronic ^® PE or PLURIOL ^® RPE brands of BASF SE.

Suitable polyester polyols are, for example, the known polycondensates of di- and optionally tri- and tetraols and di- and optionally tri- and tetracarboxylic acids or hydroxycarboxylic acids or lactones. Instead of the free polycarboxylic acids, it is also possible to use the corresponding polycarboxylic acid anhydrides or corresponding polycarboxylic acid esters of lower alcohols for the preparation of the polyesters or mixtures of at least two thereof.

Examples of suitable diols are ethylene glycol, butylene glycol, diethylene glycol, triethylene glycol, polyalkylene glycols such as polyethylene glycol, furthermore 1,2-propanediol, 1,3-propanediol, butanediol (1,3), butanediol (1,4), hexanediol ( 1, 6) and isomers, neopentyl glycol or hydroxyphenic acid neopentyl glycol esters or mixtures of at least two thereof. In addition, it is also possible to use polyols, such as trimethylolpropane, glycerol, erythritol, pentaerythritol, trimethylolbenzene or trishydroxyethyl isocyanurate, or mixtures of at least two thereof.

As dicarboxylic acids, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, cyclohexanedicarboxylic acid, adipic acid, azelaic acid, sebacic acid, glutaric acid, tetrachlorophthalic acid, maleic acid, fumaric acid, itaconic acid, malonic acid, suberic acid, 2-methylsuccinic acid, 3,3-diethylglutaric acid and / or 2,2 Dimethyl succinic acid or mixtures of at least two thereof. The acid source used may also be the corresponding anhydrides.

If the average functionality of the polyol to be esterified is greater than 2, monocarboxylic acids, such as benzoic acid and hexanecarboxylic acid may additionally be used.

Hydroxycarboxylic acids which can be used as reactants in the preparation of a polyesterpolyol having terminal hydroxyl groups are, for example, hydroxycaproic acid, hydroxybutyric acid, hydroxydecanoic acid, hydroxystearic acid and the like, and also mix at least two of them. Suitable lactones are caprolactone, butyrolactone and homologs. Preference is given to caprolactone.

Preferred polycarbonate polyols are those which are obtainable, for example, by reaction of carbonic acid derivatives, such as diphenyl carbonate, dimethyl carbonate, diethyl carbonate or phosgene, with polyols, preferably diols. Examples of such diols are ethylene glycol, 1,2- and 1,3-propanediol, 1,3- and 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol, 1,4-bishydroxymethylcyclohexane, 2 Methyl-1,3-propanediol, 2,2,4-trimethylpentane-1,3-diol, di-, tri- or tetraethylene glycol, dipropylene glycol, polypropylene glycols, dibutylene glycol, polybutylene glycols, bisphenol A, tetrabromobisphenol A but also lactone modified diols or mixtures of at least two of these in question. As polyols for the preparation of the polycarbonate polyols and polyester polyols or polyether polyols can be used.

Preferably, the diol component for the preparation of the polycarbonate polyols contains 40 to 100% by weight of hexanediol, preferably 1,6-hexanediol and / or hexanediol derivatives, preferably those which in addition to terminal OH groups ether or ester groups, for example products by Reaction of 1 mole of hexanediol with at least 1 mole, preferably 1 to 2 moles of caprolactone or by etherification of hexanediol with itself to di- or trihexylenglycol were obtained. Polyether-polycarbonate diols can also be used. The hydroxyl polycarbonates should be substantially linear. However, they may optionally be easily branched by the incorporation of polyfunctional components, especially low molecular weight polyols. Glycerol, trimethylolpropane, hexanetriol-1,2,6, butanetriol-1,2,4, trimethylolpropane, pentaerythritol, quinitol, mannitol, sorbitol, methyl glycoside or 1,3,4,6-dianhydrohexitols are suitable for this purpose, for example. Preference is given to those polycarbonates based on 1,6-hexanediol, as well as modifying co-diols such. As butane-1,4-diol or ε-caprolactone. Further preferred polycarbonate diols are those based on mixtures of 1,6-hexanediol and 1,4-butanediol. Examples of polycarbonate polyols are found, for example, in US Pat. As in EP 1359177 A. For example, as polycarbonate diols Desmophen ^® C types of Covestro AG can be used, such as. B. Desmophen ^® C 1100 or Desmophen ^® C 2200th

In particular, the abovementioned polyether carbonate polyols, polycarbonate polyols and / or polyetherestercarbonate polyols can be obtained by reacting alkylene oxides, preferably ethylene oxide, propylene oxide or mixtures thereof, optionally further co-monomers with CO ₂ in the presence of a further H-functional initiator compound and using catalysts , These catalysts comprise double metal cyanide catalysts (DMC catalysts) and / or metal complex catalysts, for example based on the metals zinc and / or cobalt, for example zinc glutarate catalysts (described, for example, in MH Chistholm et al., Macromolecules 2002, 35, 6494), so-called zinc diiminate catalysts (described, for example, in SD Allen, J. Am. Chem. Soc. 2002, 124, 14284) and so-called cobalt-salen Catalysts (described for example in US 7,304,172 B2, US 2012/0165549 AI) and / or manganese-salen complexes. An overview of the known catalysts for the copolymerization of alkylene oxides and CO2 are, for example, Chemical Communications 47 (2011) 141-163. By using different catalyst systems, reaction conditions and / or reaction sequences, the formation of random, alternating, blocky or gradient polyethercarbonate polyols, polycarbonate polyols and / or polyetherestercarbonate polyols takes place.

The polyol component a) preferably has at least two different polyols. The at least two different polyols may differ in at least one of the following properties: i) their molecular mass;

I I) their OH functionality;

III) the structure of their repeat units;

IV) their amount in the mixture of at least two polyols;

V) all of the aforementioned properties. In a preferred embodiment of the coating composition, the polyol component a) comprises at least two different polyols, a first polyol and at least one further polyol. Preferably, the polyol component a) comprises the first polyol in an amount in a range of 0.1 to 50% by weight, or preferably in a range of 1 to 30% by weight, or preferably in a range of 5 to 20% by weight. -% on. Preferably, the polyol component comprises all other polyols in an amount ranging from 50 to 99 wt%, or in a range of 60 to 95 wt%, or preferably in a range of 70 to 90 wt%. Each of the at least two polyols is preferably selected from the group of polyols previously mentioned in connection with the polyol component a).

Suitable araliphatic starting diisocyanates for the preparation of the polyisocyanate components A) are any diisocyanates whose isocyanate groups are bonded via optionally branched aliphatic radicals to an optionally further substituted aromatic such. B. 1,3-bis (isocyanatomethyl) benzene (m-xylylene diisocyanate, m-XDI), l, 4-bis (isocyanatomethyl) benzene (p-xylylene diisocyanate, p-XDI), l, 3-bis (2-isocyanatopropane 2-yl) benzene (m-tetramethylxylylene diisocyanate, m-TMXDI), 1,4-bis (2-isocyanatopropan-2-yl) benzene (p-tetramethylxylylene diisocyanate, p-TMXDI), l, 3-bis ( isocyanatomethyl) -4-methylbenzene, 1,3-bis (isocyanatomethyl) -4-ethylbenzene, 1,3-bis (isocyanatomethyl) -5-methylbenzene, 1,3-bis (isocyanato- methyl) -4,5- dimethylbenzene, 1,4-bis (isocyanatomethyl) -2,5-dimethylbenzene, 1,4-bis (isocyanato-methyl) -2,3,5,6-tetramethylbenzene, 1,3-bis (isocyanatomethyl) -5-tert .-Butylbenzene, 1,3-bis (isocyanatomethyl) -4-chlorobenzene, 1,3-bis (isocyanatomethyl) -4,5-dichlorobenzene, 1,3-bis (isocyanato) methyl) -2,4,5,6-tetrachlorobenzene, 1,4-bis (isocyanatomethyl) -2,3,5,6-tetrachlorberizole, 1,4-bis- (isocyanatomethyl) -2,3,5,6- Tetrabromobenzene, 1, 4-bis (2-isocyanatoethyl) benzene, 1, 4-bis (isocyanatomethyl) naphthalene and any mixtures of these diisocyanates.

The abovementioned starting diisocyanates can also be reacted as polyisocyanates for the reaction with the selected polyols to give the prepolymers.

The polyisocyanate component prepared from said araliphatic diisocyanates is preferably uretdione, isocyanurate, iminooxadiazinedione, urethane, allophanate, biuret and / or oxadiazinetrione-containing polyisocyanates based on araliphatic diisocyanates which are present at 23 ° C in solid form or have a viscosity of more than 150,000 mPas, and their content of isocyanate groups of 10 to 22 wt .-% and of monomeric araliphatic diisocyanates is less than 1.0 wt .-%.

The preparation of the polyisocyanate components A) from said araliphatic diisocyanates can be prepared by the usual methods for the oligomerization of diisocyanates, as described, for. In Laos et al., J. Prakt. Chem. 336, 1994, 185-200, followed by separation of the unreacted monomeric diisocyanates by distillation or extraction. Concrete examples of low-monomer polyisocyanates of araliphatic diisocyanates can be found, for example, in JP-A 2005161691, JP-A 2005162271 and EP-A 0 081 713.

Preferred polyisocyanates A) are those with uretdione, allophanate, isocyanurate, iminooxadiazinedione and / or biuret structure. Preference is given to the preparation of the prepolymers by reacting the polyols with araliphatic starting diisocyanates, as mentioned above. The prepolymers can be freed from monomeric starting diisocyanates by thin-layer distillation. The direct reaction of the prepolymers without prior thin film distillation is preferred.

Particularly preferably, the araliphatic starting diisocyanates are those of the type described above based on xylylene diisocyanate (m-XDI, p-XDI) and / or tetramethylxylylene diisocyanate (m- and p-TMXDI). Very particular preference is given to xylylene diisocyanate (m- or p-XDI).

For the preparation of the araliphatic starting diisocyanates may by any method, for. Example, by phosgenation in the liquid phase or gas phase or on phosgene-free path, for example by urethane cleavage.

In addition to the components a) and b), it is also possible to use further isocyanate-reactive compounds for the preparation of the prepolymers. For example, at least some low molecular weight polyols can also be used for the preparation of the isocyanate-containing prepolymers. Suitable low molecular weight polyols are short-chain, ie containing 2 to 20 carbon atoms, aliphatic, araliphatic or cycloaliphatic diols or triols. Examples of diols are ethylene glycol, diethylene glycol, triethylglycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 2-ethyl-2-butylpropanediol, trimethylpentanediol, positionally isomeric diethyloctanediols , 1,3-butylene glycol, cyclohexanediol, 1,4-cyclohexanedimethanol, 1,6-hexanediol, 1,2- and 1,4-cyclohexanediol, hydrogenated bisphenol A (2,2-bis (4-hydroxycyclohexyl) propane) , 2,2-Dimethyl-3-hydroxypropionic acid (2,2-dimethyl-3-hydroxypropyl ester). Preference is given to 1,4-butanediol, 1,4-cyclohexanedimethanol and 1,6-hexanediol or mixtures of at least two thereof. Examples of suitable triols are trimethylolethane, trimethylolpropane or glycerol, preference is given to trimethylolpropane.

Furthermore, in addition to the short-chain diols, it is also possible to use low molecular weight amines or amino alcohols. Such compounds are di- or polyamines, as well as hydrazides, e.g. Hydrazine, 1,2-ethylenediamine, 1,2- and 1,3-diaminopropane, 1,4-diaminobutane, 1,6-diaminohexane, isophoronediamine, isomer mixture of 2,2,4- and 2,4,4-trimethylhexamethylenediamine, 2-methylpentamethylenediamine, diethylenetriamine, 1,3- and 1,4-xylylenediamine, α, α, α ', α'-tetramethyl-1,3- and 1,4-diaminodicyclohexylmethane, dimethyl ethylenediamine , Hydrazine, adipic dihydrazide, 1,4-bis (aminomethyl) cyclohexane, 4,4'-diamino-3,3'-dimethyldicyclohexylmethane and other (G-C4) di- and tetraalkyldicyclohexylmethanes, eg 4,4'-diamino-3,5-diethyl-3 ', 5'-diisopropyldicyclohexylmethane or mixtures of at least two thereof. As diamines or amino alcohols are generally suitable low molecular weight diamines or amino alcohols containing active hydrogen with respect to NCO groups of different reactivity, such as compounds which in addition to a primary amino group also secondary amino groups or in addition to an amino group (primary or secondary) also OH Groups. Examples of these are primary and secondary amines, preferably selected from the group consisting of 3-amino-1-methylaminopropane, 3-amino-1-ethylaminopropane, 3-amino-1-cyclohexylaminopropane, 3-amino-1-methylaminobutane, furthermore amino alcohols, such as N-aminoethylethanolamine, ethanolamine, 3-aminopropanol, neopentanolamine and diethanolamine or mixtures of at least two thereof. Diethanolamine is preferably used.

Furthermore, it is also possible to use monofunctional compounds which are reactive with NCO groups, such as monoamines, in particular mono-secondary amines or monoalcohols. Examples of these are ethanol, n-butanol, ethylene glycol monobutyl ether, 2-ethylhexanol, 1-octanol, 1-dodecanol, 1-hexadecanol, methylamine, ethylamine, propylamine, butylamine, octylamine, laurylamine, stearylamine, isononyloxypropylamine, dimethylamine, Diethylamine, dipropyla- min, dibutylamine, N-methylaminopropylamine, diethyl (methyl) aminopropylamine, Μο ΐιοϋη, piperidine and suitable substituted derivatives thereof or mixtures of at least two from the list of the aforementioned compounds.

The isocyanate-terminated prepolymer is prepared by reacting components a) and b) and optionally other isocyanate-reactive components with one another, preferably by reacting components a) and b) with one another.

In the preparation of the prepolymer, the polyol component a) may be initially charged and then the isocyanate component b) may be added or else be proceeded in the reverse order. The reaction is preferably carried out at temperatures in a range of 23 and 120 ° C, or preferably in a range of 50 to 100 ° C. The temperature guide can be varied before and after the addition of the individual components in this area. The reaction can be carried out with the addition of common solvents or in bulk, preferably in bulk. The reaction can be carried out without catalyst, but also in the presence of catalysts which accelerate the formation of urethanes from isocyanates and polyol components.

To accelerate the reaction, it is possible, for example, to use customary catalysts known from polyurethane chemistry as component C) in the coating composition. Examples may be mentioned here tert. Amines, such as B. triethylamine, tributylamine, dimethylbenzylamine, diethylbenzylamine, pyridine, methylpyridine, dicyclohexylmethylamine, dimethylcyclohexylamine, Ν, Ν, Ν ', Ν'-tetramethyldiaminodiethylether, bis (dimethylaminopropyl) - urea, N-methyl or N-ethylmorpholine, N- Cocomorpholine, N-cyclohexylmorpholine, N, N, N ', N'-tetramethylethylenediamine, N, N, N', N'-tetramethyl-1,3-butanediamine, Ν, Ν, Ν ', Ν'-tetramethyl-1, 6-hexanediamine, pentamethyldiethylenetriamine, N-methylpiperidine, N-dimethylaminoethylpiperidine, Ν, Ν'-dimethylpiperazine, N-methyl-N'-dimethylaminopiperazine, 1,8-diazabicyclo (5.4.0) undecene-7 (DBU) , 1,2-dimethylimidazole, 2-methylimidazole, N, N-dimethylimidazole-.beta.-phenylethylamine, 1,4-diazabicyclo- (2,2,2) -octane, bis- (N, N-dimethylaminoethyl) adipate; Alkanolamine compounds, such as. Triethanolamine, triisopropanolamine, N-methyl- and N-ethyl-diethanolamine, dimethylaminoethanol, 2- (N, N-dimethylaminoethoxy) ethanol, N, N ', N "-tris- (dialkylaminoalkyl) hexahydrotriazines, eg N, N' , N "-tris- (dimethylaminopropyl) -s-hexahydrotriazine and / or bis (dimethylaminoethyl) ether; Metal salts, such as. As inorganic and / or organic compounds of iron, lead, bismuth, zinc, and / or tin in the usual Oxidati- onsstafen of the metal, for example, iron (II) chloride, iron (III) chloride, bismuth (III) - bismuth (III) 2-ethylhexanoate, bismuth (III) octoate, bismuth (III) neodecanoate, zinc chloride, zinc 2- ethyl caproate, stannous octoate, stannous ethyl caproate, stannous palmitate, dibutyltin (IV) dilaiate (DBTL), dibutyltin (IV) dichloride or lead octoate; Amidines, such as. For example, 2,3-dimethyl-3,4,5,6-tetrahydropyrimidine; Tetraalkylammoniumhydroxide, such as. Tetramethylammonium hydroxide; Alkali hydroxides, such as. For example, sodium hydroxide and alkali metal such as. As sodium methylate and potassium isopropylate, and alkali metal salts of long-chain fatty acids having 10 to 20 carbon atoms and optionally pendant OH groups.

Preferably used catalysts C) are tertiary amines, bismuth and tin compounds of the type mentioned.

The catalysts mentioned by way of example can be used in the preparation of the coating composition according to the invention individually or in the form of any mixtures with one another and optionally in amounts of 0.01 to 5.0 wt .-%, preferably 0.1 to 2 wt .-%, calculated as the total amount of catalysts used, based on the total amount of the starting compounds used.

The terminal isocyanate groups of the prepolymers are blocked with N-alkyl-benzylamine or partially with N-alkyl-benzylamine and partially with 3,5-dimethylpyrazole (DMP), preferably exclusively with N-alkyl-benzylamine.

Suitable blocking agents are N-alkyl-benzylamines according to the definition as described in paragraph [0014] and [0015] of DE 102004057916. Very particular preference is given from this class of derivatives to N-benzyl-tert-butylamine. Mixtures of these benzylamine-based blocking agents with 3,5-dimethylpyrazole are also possible.

In a preferred embodiment of the coating composition, the terminal isocyanate groups of the prepolymer are blocked with N-tert-butylbenzylamine.

For blocking, the isocyanate-terminated prepolymers are completely or partially reacted with the blocking agents. The blocking agent is preferably used in the amount such that the equivalents of isocyanate blocking suitable groups of the blocking agent at least 30 mol .-%, or preferably at least 50 mol .-%, or preferably at least 95 mol .-%, of the amount of corresponding blocking isocyanate groups. A slight excess of blocking agent may be useful to ensure complete reaction of all isocyanate groups. As a rule, the excess is not more than 20 mol%, preferably not more than 15 mol%, or preferably not more than 10 mol%, based on the total content of the isocyanate groups to be blocked. Most preferably, the amount of NCO blocking suitable th groups of the blocking agent therefore at 95 mol .-% to 110 mol .-%, based on the amount of isocyanate groups to be blocked of the polyurethane prepolymer.

The blocking of the terminal isocyanate groups with DMP and secondary N-alkylbenzylamines is advantageously carried out at temperatures of 23 ° C to 100 ° C, or preferably at temperatures of 40 to 90 ° C. The blocking agents are preferably first added to the prepolymer in pure form. As the reaction proceeds, a large increase in viscosity may occur depending on the structure of the prepolymer. In this case, common solvents can then be added to limit the increase in viscosity.

The viscosity of the resulting blocked prepolymers is preferably <200,000 mPas, or preferably <150,000 mPas, or preferably <110,000 mPas. The viscosity can also be adjusted by adding organic solvents, wherein <30 wt .-%, preferably <20 wt .-%, or preferably <10 wt .-%, or preferably <6 wt .-% of organic solvent, be used based on the total mass of prepolymer and solvent.

The coating composition further contains component B), at least one polyamine. Polyamines according to the invention are understood as meaning those amines which have at least two amino groups.

In a preferred embodiment of the coating composition, component B) comprises at least one diamine, or component B) consists exclusively of one or more diamines. Such polyamines may contain either primary or secondary amino groups or mixtures of these.

Examples of suitable polyamines are: hydrazides, for example hydrazine, 1,2-ethylenediamine, 1,2- and 1,3-diaminopropane, 1,4-diaminobutane, 1,6-diaminohexane, isophoronediamine, isomer mixtures of 2, 2,4- and 2,4,4-trimethylhexamethylenediamine, 2-methylpentamethylenediamine, diethylenetriamine, 1,3- and 1,4-xylylenediamine, α, α, α ', α'-tetramethyl-1,3- and -1, 4-xylylenediamine and 4,4-diaminodicyclohexylmethane, dimethylethylenediamine, hydrazine, adipic dihydrazide, 1,4-bis (aminomethyl) cyclohexane, 4,4'-diamino-3,3'-dimethyldicyclohexylmethane and other (Ci-C4) -Di - And Tetraalkyldicyclohe- xylmethane, for example, 4,4'-diamino-3,5-diethyl-3 ', 5'-diisopropyldicyclohexylmethan, 4,4'-diamino-3,3'5,5'-tetramethyldicyclohexylmethane or mixtures of at least two hereof. Also suitable as suitable polyamines are low molecular weight diamines or amino alcohols which contain active hydrogen with NCO groups of different reactivity, such as compounds which, in addition to a primary amino group, also have secondary amino groups or OH groups in addition to an amino group (primary or secondary). Examples of these are primary and secondary amines, such as 3-amino-1-methylaminopropane, 3-amino-1-one Ethylaminopropane, 3-amino-1-cyclohexylaminopropane, 3-amino-1-methylaminobutane, furthermore amino alcohols, such as N-aminoethylethanolamine, ethanolamine, 3-aminopropanol, neopentanolamine and preferably diethanolamine or mixtures of at least two thereof.

Suitable polyamines are also secondary polyamines which have ester groups, the so-called polyaspartates. Polyaspartates are available by reacting primary polyamines with maleates or fumarates. The primary polyamines may in particular be selected from the group consisting of ethylenediamine, 1,2- and 1,3-propanediamine, 2-methyl-1,2-propanediamine, 2,2-dimethyl-1,3-propanediamine, 1, 3- and 1,4-butanediamine, 1,3- and 1,5-pentanediamine, 2-methyl-1,5-pentanediamine, 1,6-hexanediamine, 2,5-dimethyl-2,5-hexanediamine, 2, 2,4- and / or 2,4,4-trimethyl-l, 6-hexanediamine, 1 J-heptanediamine, 1, 8-octanediamine, 1,9-nonanediamine, 1,1 O-decanediamine, 1,11-undecanediamine , 1,12-dodecanediamine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 2,4- and / or 2,6-hexahydrotoluenediamine, 2,4'- and / or 4,4'-diaminodicyclohexylmethane , 3,3'-Dialkyl-4,4'-diamino-dicyclohexylmethanes (such as 3,3'-dimethyl-4,4'-diamino-dicyclohexylmethane and 3,3'-diethyl-4,4'-diamino-dicyclohexyl - methane), 4,4'-diamino-3,3 ', 5,5'-tetramethyl-dicyclohexylmethane, 1,3- and / or 1,4-cyclohexanediamine, 1, 3-bis (methylamino) -cyclohexane, 1 , 8-p-methanediamine, hydrazine, hydrazides of semicarbazido carboxylic acid, bis-hydra zide, bissemicarbazide, phenylenediamine, 2,4- and 2,6-toluenediamine, 2,3- and 3,4-toluenediamine, 2,4 · and / or 4,41-diaminodiphenylmethane, more highly functionalized polyphenylpolymethylpolyamines obtainable from the aniline / Formaldehyde condensation reaction, N, N, N-tris- (2-aminoethyl) -amine, guanidine, melamine, N- (2-aminoethyl) -1,3-propanediamine, 3,3-diaminobenzidine, polyox propyleneamines, polyoxyethyleneamines, mixed propylene oxide / ethylene oxide diamines (such as 3,3 · - [1,2-ethanediylbis (oxy)] bis (1-propanamine)), 2,4-bis- (4-aminobenzyl) -aniline, and mixtures of at least two it. Preferred primary polyamines are 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane (isophorone diamine or IPDA), bis (4-aminocyclohexyl) methane, bis (4-amino-3-methylcyclohexyl) -methane, 1 , 6-diamino-hexane, 2-methylpentamethylenediamine, ethylenediamine and 3,3 · - [1,2-ethanediylbis (oxy)] bis (1-propanamine).

Suitable polyaspartates and their preparation are described, for example, in patent applications US2005 / 0159560 A1, EP0403921 A1, EP0470461 A1 and in US Pat. Nos. 5,126,170, 5,214,086, 5,236,741, 5,243,012, 5,364,955, 5,412,056, 5,623,045, 5,736,604, 6, 183,870, 6,355,829, 6,458,293 and 6,482,333 and in published European patent application 667,362. Furthermore, aspartates are known which include aldimine groups (see US Pat. Nos. 5,489,704, 5,559,204 and 5,847,195). Secondary aspartic acid amide esters are known from US Pat. No. 6,005,062. Component B) preferably comprises 4,4'-diaminocyclohexylmethane, 4,4'-diamino-3,3'-dimethyldicyclohexylmethane and 4,4'-diamino-3,3'5,5'-tetramethyldicyclohexylmetlian, or mixtures of at least two thereof ,

In a preferred embodiment of the coating composition, the ratio of the isocyanate groups in component b) to hydroxyl groups in component a) is> 1.5: 1, or preferably> 1.8: 1, or preferably> 1.9: 1.

The polyol component a) preferably comprises or consists of a mixture of at least two polyol components, where the individual polyols may consist of polyether polyols, polyester polyols, polycarbonate polyols, polyether carbonate polyols, polyester carbonate polyols and polyetheresterocarbonate polyols preferably selected from the polyols described above. The number-average molecular weights M _{n of} the polyols are preferably in the range from 500 to 6000 g mol, the average OH functionality preferably in the range 1.8 to 3.5, particularly preferably in a range from 2.0 to 3.0.

The coating composition preferably contains from 5 to 50% by weight or preferably from 5 to 30% by weight of component B), based on the total weight of the coating composition.

In a preferred embodiment of the coating composition, the coating composition contains <30% by weight, preferably <15% by weight, or preferably <10% by weight, based on the total composition of coating composition, of at least one organic solvent C. Therefore, the coating composition be referred to as low in solvents. Suitable organic solvents are all solvents customary in the textile industry; esters, alcohols, ketones, for example butyl acetate, methoxypropyl acetate, methyl ethyl ketone or mixtures of at least two of these solvents are particularly suitable. Particularly preferred is methoxypropyl acetate.

The organic solvent can be added together with component A), component B), but also separately before, during or after the mixing of A) and B). The organic solvent is preferably introduced into the composition together with component A). Alternatively, the solvent is preferably added after mixing components A) and B).

In a preferred embodiment, the coating composition does not comprise water. In the coating composition according to the invention, the weight ratio of component A) to component B) is preferably <10: 4, particularly preferably <10: 3.5 and very particularly preferably <10: 3. In a preferred embodiment of the coating composition, component b) has an average NCO functionality in a range from 1.5 to 4.0, preferably in a range from 1.8 to 3.8 or preferably in a range from 2.0 to 3.5 on.

In a preferred embodiment of the coating composition, the weight ratio of component A) to component B) is <10: 3, or preferably <10: 2 or preferably <10: 1.5.

The ratio of component A) to component B) is preferably selected so that amine groups to blocked NCO groups in an equivalent ratio of 0.8 to 1.1, more preferably from 0.9 to 1.05 and most preferably from 0.95 to 1.0 are present. The coating compositions according to the invention may further comprise the auxiliaries and additives known per se in textile coating processing, such as, for example, As pigments, UV stabilizers, antioxidants, fillers, blowing agents, matting agents, handle additives, antifoaming agents, light stabilizers, plasticizers and / or flow control agents. These auxiliaries and additives are preferably present in a concentration <15% by weight, more preferably 0.01% to 10% by weight, based on the total weight of the coating composition.

The coating composition preferably comprises 30 to 95% by weight of component A), 2 to 50% by weight of component B), 0 to 15% by weight of component C) and 0 to 15% by weight of auxiliary and additives, wherein the components A), B), C) and the auxiliaries and additives to 100 wt .-% complement. The coating composition is preferably prepared by mixing all components at 20 to 30 ° C for 20 to 50 minutes. In particular, the components A) and B) are advantageously first stored separately and mixed only as soon as possible before the application or processing of the coating composition.

The coating composition preferably has a viscosity immediately after the mixing of the components, which still makes it possible to process the coating composition by the common methods used in the textile industry, in particular by knife coating. The viscosity of the coating composition may also be influenced by auxiliaries and additives, such as those mentioned above.

The coating composition should still be processable for at least 4 hours after mixing.

Another object of the invention is a method for coating substrates, wherein the coating composition according to the invention applied to a substrate and in a Temperature in a range of 90 to 200 ° C, preferably in a range of 110 to 180 ° C, or preferably in a range of 130 to 170 ° C is crosslinked. The crosslinking takes place by reaction of the components A) and B) with each other, in particular triggered by the effect of temperature. The blocked polyisocyanate A) initially passes at least partially into an unblocked form as a result of the action of temperature, and the blocked polyisocyanate A) particularly preferably passes completely into an unblocked form. The deblocked isocyanate groups can then react with the amino groups of component B) with crosslinking.

Crosslinking is particularly preferably carried out using temperature profiles in which the temperature is increased stepwise in the specified temperature range over the course of the crosslinking time.

The crosslinking time under the influence of temperature is altogether preferably from 1 to 15 minutes, particularly preferably from 2 to 10 minutes and very particularly preferably from 2 to 5 minutes.

The coating compositions according to the invention can be applied to the substrate in one or more layers.

The coating composition can be mixed with the usual coating or coating equipment, for example a squeegee, e.g. As a doctor blade, rollers or other devices are applied to the substrate. Also printing, spraying is possible. Preferably, the application is carried out by doctoring. The application can be done on one or both sides. The order can be made directly or via a transfer coating, preferably via transfer coating.

In the process according to the invention, amounts of from 100 to 1000 g / m ² are preferably applied to the substrate.

Suitable substrates are preferably textile materials, surface substrates of metal, glass, ceramic, concrete, natural stone, leather, natural fibers, and plastics such as PVC, polyolefins, polyurethane or the like. Three-dimensional structures are also suitable as carrier materials. The substrate is particularly preferably a textile material or leather, very particularly preferably a textile material.

In a preferred embodiment of the method, the substrate is a textile material.

For the purposes of the present invention, textile materials are, for example, fabrics, fabrics, bonded and unbonded nonwovens. The textile materials may be composed of synthetic, natural fibers and / or mixtures thereof. In principle, textiles made of any desired fibers are suitable for the process according to the invention. By the invention In accordance with the coating composition, the substrates may be treated in all conventional manners, preferably by coating or bonding the fibers together or substrates to each other.

The coated textile substrates can be surface-treated before, during or after the application of the coating composition according to the invention, eg. B. by pre-coating, grinding, velorizing, roughening and / or tumbling.

In the textile coating, a multi-layer construction is often used. The coating then preferably consists of at least two layers, which are generally referred to as dashes. The uppermost, the air-facing layer is referred to as the top coat. The lowermost side facing the substrate, which joins the top coat or further layers of the multi-layer structure to the textile, is also referred to as an adhesive line. In between, one or more layers can be applied, which are generally referred to as intermediate streaks.

By means of the coating method according to the invention, it is possible in connection with textile materials to produce toppings, intermediate lines and even adhesive lines. Especially suitable is the process for producing intermediate strokes. The intermediate strokes can be in a compact or foamed form. Foaming agents can be used to produce foamed intermediate streaks. Suitable propellants are known from the prior art. In particular, it is also particularly advantageous for the compositions according to the invention that they can be used to produce thick layers with only one or very few lines.

Likewise provided by the invention is a coated substrate obtainable by the process according to the invention.

Because of the outstanding performance properties, the coating compositions according to the invention or the layers or bonds produced from them are preferably suitable for coating or producing substrates selected from the group consisting of outerwear, artificial leather articles, such as shoes, furniture upholstery materials, automotive interior trim materials and sporting goods or Combinations of at least two of these. This list is merely illustrative and not limiting. Furthermore, the use of the coating composition according to the invention for the production of elastic coatings or elastic films is the subject of the invention. Elastic films and coatings in the sense of this invention preferably have an elongation at break of> 200%, preferably of> 300%, or preferably of> 400%), and / or a tensile strength of> 2 MPa or preferably of> 3 MPa and a 100% modulus of> 0.2 MPa or preferably> 0.3 MPa. Another object of the invention is an elastic film comprising a coating composition according to the invention preferably prepared by the process according to the invention, wherein the elastic film has an elongation at break of>200%>,preferably> 300%, or preferably> 400%), and / or a Breaking stress of> 2 MPa, or preferably> 3 MPa.

In a preferred embodiment of the elastic film, the film has a 100% modulus of> 0.2 MPa, or preferably of> 0.3 MPa.

The elastic films or coatings preferably have a swellability in water of <50%), more preferably <30% and most preferably <10%.

To determine the degree of swelling, the free films were swollen in ethyl acetate at room temperature for 24 h and the volume change of the film piece after swelling was determined by means of a ruler.

For this purpose, a 0.1 to 0.2 mm thick film was punched out in a size of 50 * 20 mm and stored for 2 hours in ethyl acetate at room temperature. The calculation of the volume swelling was made assuming that the change in all the dimensions is proportional to each other.

The stated physical properties are determined as described in the method section.

The present invention will be illustrated by way of examples, which are not to be construed as limiting.

Experimental part:

methods:

All percentages are by weight unless stated otherwise. The NCO contents were determined titrimetrically in accordance with DIN EN ISO 11909.

All viscosity measurements were carried out with a Physica MCR 51 Rheometer from Anton Paar GmbH (DE) according to DIN EN ISO 3219. The measurements of the 100% modules, the breaking stress and the elongation at rupture were carried out according to DIN 53504.

The number average molecular weight M _n was determined by gel permeation chromatography (GPC) in tetrahydrofuran at 23 ° C. The procedure was according to DIN 55672-1: "Gel Permeation Chromatography, Part 1 - Tetrahydrofuran as Eluent" (SECurity GPC system from PSS Polymer Service, flow rate 1.0 ml / min, columns: 2xPSS SDV linear M, 8 × 300 mm, 5 μm RID detector). In this case, polystyrene samples of known molecular weight were used for calibration. The calculation of the number average molecular weight was software-based. Baseline points and evaluation limits were determined in accordance with DIN 55672 Part 1.

Description of the raw materials:

All starting materials mentioned below are products of Covestro Deutschland AG. Polyol 1: Trifunctional polyether of propylene oxide and ethylene oxide, started on glycerol, number average molecular weight M _n = 6000 g / mol

Polyol 2: difunctional polypropylene oxide ether, started with bisphenol A, number average molecular weight M _n = 560 g / mol

Polyol 3: Trifunctional polypropylene oxide ether started with glycerine and started with glycerol, number average molecular weight M _n = 3005 g / mol

Polyol 4: Difunctional polypropylene oxide ether, started with 1,2-propylene glycol, number average molecular weight M _n = 2000 g / mol

Polyol 5: Difunctional polyester polyol of adipic acid and 1,6-hexanediol and neopentyl glycol, number average molecular weight M _n = 2000 g / mol Polyol 6: Difunctional polypropylene oxide ether, started with 1,2-propylene glycol, number average molecular weight M _n = 1000 g / mol

Polyol 7: Difunctional polyester polyol of adipic acid and 1,6-hexanediol and neopentyl glycol, number average molecular weight M _n = 1700 g / mol

Polyisocyanate 1: meta-xylylene diisocyanate (XDI) Polyisoc anate 2: 4,4'-methylene bis (phenyl isocyanate), pure 4,4'-isomer (MDI)

Polyisocyanate 3: Toluylene diisocyanate (20% 2,6-tolylene diisocyanate and 80% 2,4-toluene diisocyanate)

Polyisocyanate 4: Toluylene diisocyanate (100% 2,4-tolylene diisocyanate) Polyisocyanate 5: Hexamethylene 1,6-diisocyanate (HDI) Polyisocyanate 6: Isophorone diisocyanate (IPDI)

Diamine 1: 4,4'-diamino-3,3'-dimethiyldicycloxylmxylamine (Laromin C 260, BASF, Germany) diamine 2: 4,4'-diaminodicycloliexylmetlian

N -Benzyl tert -butylamine (BEBA): The material was purchased from Vertellus, Indianapolis, USA. 1-Methoxy-2-propylacetate (MPA)

All other starting materials were purchased from Sigma Aldrich and used without further purification unless otherwise specified in the specific case.

General procedure for the inventive and noninventive Examples 1 to 4 with the compositions as indicated in Table 1:

The respective polyol mixture was stirred in a dehydration step at a pressure of 10 mbar for 1 h at 100 ° C to remove excess water from the mixture. When the mixture contained 1,4-butanediol, this component was added to the polyol mixture only after the dehydration step. The polyol mixture was then adjusted to 65 ° C. and the amounts of Vulkanox BHT and triphenylphosphine indicated in Table 1 were added and this mixture was homogenized by stirring at 65 ° C. for 10 minutes. Within 1 min, the diisocyanates indicated in Table 1 were then added at this temperature (in the case of mixtures of diisocyanates, first the polyisocyanate 2, then the polyisocyanate 3). A slightly exothermic reaction was noted which heated the mixture to a maximum of 75 ° C. The temperature was allowed to fall back to 65 ° C and the reaction mixture was stirred at 65 ° C until the content of free NCO groups had fallen to the theoretical content. At a temperature of 65 to 70 ° C then a stoichiometric amount of N-benzyl-tert-butylamine, which corresponds to the NCO content determined in the reaction mixture, was added within about 1 min. A slight exothermic reaction was noted as the temperature of the reaction mixture increased up to a maximum of 5 ° C. If the viscosity of the reaction mixture increased too much, MPA was added during the reaction. The mixture was stirred until the NCO content had dropped to zero according to IR spectroscopy (band at 2260 cm ^-1 ) or determined by NCO titration If appropriate, the reaction mixture was diluted after completion of the reaction by addition of some MPA.

The reaction with DMP proceeded in a similar manner, except that the DMP was added as a solid at 65 ° C after about 15 minutes of theoretical countercurrent NCO. It was allowed to react at this temperature as described for the other blocking agent until the NCO content dropped to zero. Depending on the change in the viscosity of the reaction mixture was diluted during the reaction or after completion of the reaction with the amount of MPA shown in Table 1.

Synthesis of Aliphatic Prepolymers Blocked with BEBA. Comparative Example 5: A mixture of 774.0 g of Polyol 1 and 48.0 g of Polyol 2 was stirred at 100 ° C and a reduced pressure of 10 mbar for 1 hour to remove excess water. Thereafter, 46.6 g of HDI were first added to this mixture at 75 ° C. within 1 to 2 minutes, followed immediately by 64.6 g of IPDI. The mixture was stirred at 75 ° C. for 5 h and at 85 ° C. for 9 h. The titrated NCO value showed that the reaction of the NCO groups with the OH groups was complete. At a temperature of 65-70 ° C then a stoichiometric amount of N-benzyl-tert-butylamine (93.7 g), which corresponds to the determined in the reaction mixture NCO content, added dropwise within about 15 min. A slight exothermic reaction was noted as the temperature of the reaction mixture increased up to a maximum of 5 ° C. The mixture was stirred for 3.5 hours until the NCO content had fallen to zero according to IR spectroscopy (band at 2260 cm ^-1 ), the batch was diluted with 55 g of MPA and a clear viscous liquid was obtained RT, the batch was crystallized and no longer suitable for film production.The storage stability of this blocked prepolymer was severely limited and only took a few minutes.

Comparative Example 6:

A mixture of 439.0 g of polyol 6 and 219.0 g of polyol 2 was stirred at 100 ° C and a reduced pressure of 10 mbar for 1 h to remove excess water. Thereafter, to this mixture was added at 65 ° C within 1 to 2 minutes 184.8g HDI. The mixture was stirred at 65-70 ° C. for 3 h and at 80 ° C. for 11 h. The titrated NCO value showed that the reaction of the NCO groups with the OH groups was complete.

At a temperature of 65-70 ° C then a stoichiometric amount of N-benzyl-tert-butylamine (93.7 g), which corresponds to the determined in the reaction mixture NCO content, added dropwise within about 15 min. After addition of this amine, 55 g of MPA were added at the same temperature. A slight exothermic reaction was noted as the temperature of the reaction mixture increased up to a maximum of 85 ° C. The heating bath was removed and stirred for 30 minutes, in which the free isocyanate groups reacted with the secondary amine groups. After 1 h, the temperature had dropped to 70 ° C and an incipient cloudiness was observed. After a further 2 h of stirring, the batch was no longer stirrable. After cooling to room temperature, the reaction mixture was through-hardened. The reaction product was no longer stirrable and only still poorly soluble in solvents. For a film production, this approach was only partially suitable.

The two preceding comparative examples 5 and 6 with aliphatic diisocyanates show that these prepolymers solidify very quickly after blocking with N-benzyl-tert-butylamine. For the production of films with aliphatic diamines, such approaches can not be used in contrast to the inventive prepolymers.

General regulation for the investigation of the pot life

The prepolymers of Examples 1 to 4 and Comparative Examples 1 to 4 were mixed in a plastic vessel with respect to the blocked amounts of NCO stoichiometric amounts of diamine 1 and 1 min. Mixed at Speed mixer at 3500 U / min. At very high processing viscosity, as in Examples 2 to 4 and the corresponding Comparative Examples 2 to 4, the amounts of MPA indicated in Table 2 were added. The mixture is stored at RT and the viscosity development of the reaction mixture is measured after the times given in Table 2.

The prepolymers prepared with m-XDI as the diisocyanate component show no significant reaction when stored at room temperature in admixture with an aliphatic diamine. Such mixtures can be easily processed over a working day at any time. The mixture has a sufficient pot life.

Those prepolymers made with aromatic diisocyanates (MDI or TDI or mixtures thereof) react well with the aliphatic amine after their contact at room temperature. The viscosity of these mixtures doubles up to threefold within one working day; after standing for one day, the mixtures are solid. Such mixtures can not be processed during a working day. The pot life is significantly shorter.

Film preparation from the prepolymers according to the invention (with XDI as Diisocyanatkompo- nente) and the diamine 1 as component B).

The inventive prepolymers of Examples 1 to 4 were reacted with the stoichiometric amount of diamine 1, 3% BYK 9565 (additive for PU-based synthetic leather, BYK Chemie GmbH, DE) and 0.5% Acronal L 700 (acrylic resin in 50% ethyl acetate, plasticizer for coatings, BASF, DE) and stirred for 3 minutes under vacuum. Supermatt on BOR release paper is a wet film layer of 300 μπι geräkelt.

The film was dried with the following parameters in a convection oven:

1 minute 90 ° C, within 1 minute to 130 ° C, heat for 1 minute 130 ° C, within 2 minutes to 160 ° C, 5 min 160 ° C.

Tensile tests to determine the breaking stress and breaking elongation of the obtained elastic films were carried out in accordance with DIN 53504. Table 3: Tensile tests:

The inventive prepolymer of Example 1 was blended with the stoichiometric amount of diamine 2 and formulated, curled and cured to film as described above. The tensile test of the resulting film gave the following results.

Table 4: Tensile tests

The results show that the inventive prepolymers with m-XDI as diisocyanate components give elastic films when crosslinked with an aliphatic diamine. The prepolymers of Comparative Examples Ibis 4 were not investigated because the reaction of the blocked isocyanate groups with the aliphatic diamine started already uncontrollably at ambient temperatures and due to the short pot life no technically utilizable formulations were obtained. Results from the viscosity measurements or also called investigations on pot life, as listed in Table 2 to Comparative Examples 1 to 4 and Examples 1 to 4 according to the invention are shown graphically in Figures 1 to 8. In detail shows

FIG. 1 is a bar graph of the viscosity increase of Comparative Example 1 over a period of 3 hours;

Figure 2 is a bar graph of the viscosity increase of Example 1 over a period of 24 hours;

FIG. 3 is a bar graph of the viscosity increase of Comparative Example 2 over a period of 7 hours;

Figure 4 is a bar graph of the viscosity increase of Example 2 over a period of 24 hours;

FIG. 5 is a bar graph of the viscosity increase of Comparative Example 3 over a period of 7 hours;

FIG. 6: a bar graph relating to the viscosity increase of example 3 over a time span of 24 hours;

FIG. 7 is a bar graph of the viscosity increase of Comparative Example 4 over a period of 7 hours; FIG. 8: a bar graph relating to the viscosity increase of Example 4 over a period of 24 hours.

FIG. 1 illustrates the development of the viscosity of the mixture from Comparative Example 1 after addition of the amounts of diamine as indicated in Table 2 to the prepolymer prepared from aromatic polyisocyanates as component b) over 3 hours. It can be seen that within the first 3 hours an increase of the viscosity of about 47,300 MPa to a value above 100,000 MPa is observed, which represents a doubling of the viscosity values. Therefore, after 7 hours, this mixture was no longer processable, since it was completely solid, as can be seen from the values in Table 2.

FIG. 2 shows the viscosity development of Inventive Example 1 from Table 2 after the addition of the diamine. Here it can be clearly seen on the bars at the times 0, 1, 2, 3, 7 and 24 hours that the viscosity changes only very moderately, namely by no more than 15% of the value at time t = 0 over this period and a workability over 24 h is guaranteed.

FIG. 3 illustrates the evolution of the viscosity of the mixture from Comparative Example 2 after addition of the amounts of diamine as indicated in Table 2 to the prepolymer prepared from aromatic polyisocyanates as component b) over 7 hours. It can be seen that within the first 3 hours, the viscosity has risen from about 21,000 MPas to a value above 80,000 MPas, which is a quadrupling of the viscosity values. Therefore, after 24 hours, this mixture was no longer processable, since it was completely solid, as can be seen from the values in Table 2.

FIG. 4 shows the viscosity development of Inventive Example 2 from Table 2 after the addition of the diamine. Here it can be clearly seen on the bars at the times 0, 1, 2, 3, 7 and 24 hours that the viscosity changes only very moderately, namely by no more than 15% of the value at time t = 0 over this period and a processability over 24 h is guaranteed.

FIG. 5 illustrates the evolution of the viscosity of the mixture from Comparative Example 3 after addition of the amounts of diamine as indicated in Table 2 to the prepolymer prepared from aromatic polyisocyanates as component b) over 7 hours. It can be seen that within the first 3 hours, the viscosity has risen from about 64,000 MPas to a value above 240,000 MPas, which is a quadruplication of the viscosity values. Therefore, after 24 hours, this mixture was no longer processable, since it was completely solid, as can be seen from the values in Table 2.

FIG. 6 shows the viscosity development of Inventive Example 3 from Table 2 after the addition of the diamine. Here it can be clearly seen on the bars at the times 0, 1, 2, 3, 7 and 24 hours that the viscosity changes only very moderately, namely by no more than 15% of the value at time t = 0 over this period and a workability over 24 h is guaranteed. FIG. 7 illustrates the evolution of the viscosity of the mixture of Comparative Example 4 after addition of the amounts of diamine as indicated in Table 2 to the prepolymer prepared from aromatic polyisocyanates as component b) over 7 hours. It can be seen that within the first 3 hours, the viscosity has risen from about 14,000 MPas to a value above 38,000 MPas, which is more than a tripling of the viscosity values. Therefore, after 24 hours, this mixture was no longer processable, since it was completely solid, as can be seen from the values in Table 2.

FIG. 8 shows the viscosity development of Inventive Example 4 from Table 2 after the addition of the diamine. Here it can be clearly seen on the bars at the times 0, 1, 2, 3, 7 and 24 hours that the viscosity is only very moderate, namely not more than 15% of the value at time t = 0 over this Period changes and a workability over 24 h is guaranteed.

From the results of the experiments as shown in Table 2 and in Figures 1 to 8, it can be read that by the use of araliphatic isocyanates as component b) for preparing the coating composition according to the invention compared to aromatic isocyanates for the preparation of coating compositions with otherwise identical components a pot life extension of at least 100%, more preferably 300%, more preferably of 500%, based on the pot life with the respective comparable aromatic isocyanate is made possible.

Claims

Claims 1. A coating composition for the elastic coating of textile materials comprising

at least one blocked, isocyanate-terminated prepolymer (component A), wherein the isocyanate-terminated prepolymer is prepared from a polyol component a) and an araliphatic isocyanate component b), and the terminal isocyanate groups with N-alkyl-benzylamines or partially with N-alkyl-benzylamines and partially blocked with 3,5-dimethylpyrazole,

at least one polyamine (component B) and

<30 wt .-%, based on the total mass of the coating composition of at least one organic solvent.

2. The coating composition according to claim 1, wherein the terminal isocyanate groups of the isocyanate-terminated prepolymer consist of tetramethylxylylene diisocyanate (m- or p-TMXDI) or xylylene diisocyanate (m- or p-XDI) or a mixture thereof, preferably of xylylene diisocyanate (m- or p-XDI). XDI).

3. The coating composition according to any one of claims 1 or 2, wherein the polyol component a) contains at least two different polyols, a first and at least one further polyol,

4. The coating composition according to any one of claims 1 to 3, wherein the terminal isocyanate groups of the prepolymer are blocked with N-tert-butylbenzylamine.

5. The coating composition according to any one of claims 1 to 4, wherein the component B) comprises at least one diamine or consists exclusively of one or more diamines.

6. The coating composition according to any one of claims 1 to 5, wherein the ratio of the isocyanate groups in component b) to hydroxyl groups in component a) is> 1.5: 1.

7. The coating composition according to any one of claims 1 to 6, wherein the coating composition contains <10 wt .-%, based on the total composition coating composition, of at least one organic solvent.

The coating composition of any of claims 1 to 7, wherein component b) has an average NCO functionality in a range of 1.5 to 4.0.

9. The coating composition according to any one of claims 1 to 8, wherein the weight ratio of component A) to component B) is <10: 3.

A process for coating substrates, wherein a coating composition according to claims 1 to 9 is applied to a substrate and crosslinked at a temperature in a range of 90 to 200 ° C.

11. The method according to claim 10, characterized in that the substrate is a textile material.

12. A coated substrate obtainable by a process according to claim 10 or 11.

13. A use of a coating composition according to any one of claims 1 to 9 for the preparation of elastic coatings or elastic films.

14. An elastic film comprising a coating composition according to any one of claims 1 to 9 or prepared according to any one of claims 10 or 11, wherein the elastic film has an elongation at break of> 200% and / or a breaking stress of> 2 MPa.

15. The elastic film according to claim 14, wherein the elastic film has a 100% modulus of> 0.2 MPa.