HK1088024B - Hydrophilized blocked polyisocyanates - Google Patents

Description

Hydrophilized blocked polyisocyanates

The invention relates to novel hydrophilicized blocked polyisocyanates, to a process for their preparation and to their use.

The procedure for blocking polyisocyanates for the temporary protection of the isocyanate groups has been known for a long time and is described, for example, in Houben Weyl's Methoden der organischen Chemie XIV/2, pages 61 to 70. Curable compositions containing blocked polyisocyanates are useful, for example, in polyurethane coatings.

Suitable blocking agents in principle are outlined, for example, in Progress in Organic Coatings 1975, 3, pages 73-79, 1981, 9, pages 3-28, and 1999, 36, pages 148-172 of Wicks et al.

Hydrophilicized blocked polyisocyanates are generally used in aqueous coating agents, the preparation of which is described, for example, in DE-A245639 and DE-A2853937.

The disadvantage of the use of hydrophilicized blocked polyisocyanates of the prior art is that a certain amount of blocking agent remains in the coating film formed after deblocking or crosslinking and adversely affects its properties. The properties of one-component coating films, such as scratch resistance and acid resistance, are inferior to so-called two-component (2K) polyurethane coatings, since blocking agents remain (e.g.T.Engbert, E.K ö nig, E.J hunens, Farbe & Lack, Curt R.Vincentz Press, Hannover 10/1995). Both the decomposition of the blocking agent and its escape from the coating film in gaseous form can lead to the formation of bubbles in the coating. From the economic and work hygiene point of view, it may also be necessary, if desired, to subsequently calcine the liberated blocking agent.

In general, in systems containing hydrophilicized blocked polyisocyanates of the prior art, the baking temperatures are from 150 to 170 ℃.

Recently, it has been found that predominantly diethyl maleate-blocked polyisocyanates can be used in aqueous 1K coating systems having lower baking temperatures of from 90 to 120 ℃ (for example EP-A0947531). Unlike blocking with, for example, N-heterocyclic compounds (e.g.caprolactam or dimethylpyrazole or butanone oxime), the blocking agents here do not decompose completely, but rather transesterify on diethyl maleate-blocked isocyanates with elimination of ethanol.

It has now been found that the blocking of hydrophilicized polyisocyanates with CH-acidic cyclic ketones gives products which react without decomposition of the blocking agent, i.e.without bleeding, and which have crosslinking temperatures of less than 150 ℃. Furthermore, these hydrophilicized blocked polyisocyanates can also be combined with other aqueous binders.

The invention relates to polyisocyanates having

i) Nonionically hydrophilicizing groups based on polyalkylene oxide polyethers having at least 30% by weight of ethylene oxide units and/or

ii) ionically or potentially ionically hydrophilicizing groups which, upon interaction with water, form a pH-dependent dissociation equilibrium and are therefore neutral or positively or negatively charged depending on the pH, and

iii) at least one structural unit of the formula (1),

wherein the content of the first and second substances,

x is an electron-withdrawing group,

R¹，R²independently of one another, is a hydrogen atom, a saturated or unsaturated aliphatic or cycloaliphatic radical, an optionally substituted aromatic radical or araliphatic radical and each contains up to 12 carbon atoms, and

n is an integer of 0 to 5.

The present invention also relates to a process for preparing the polyisocyanates according to the invention, in which the following are reacted with one another:

A) one or more organic polyisocyanates, and

B) one or more organic compounds having at least one isocyanate-reactive group comprising

b1) Nonionic hydrophilicizing groups based on polyalkylene oxide polyethers and containing at least 30% by weight of ethylene oxide units,

and/or

b2) Ionically or potentially ionically hydrophilicized groups which, upon interaction with water, form a pH-dependent dissociation equilibrium and are therefore neutral or positively or negatively charged depending on the pH,

C) a blocking agent comprising at least one CH-acidic cyclic ketone or ketones having the general formula (2),

wherein the content of the first and second substances,

x is an electron-withdrawing group,

R¹，R²independently of one another, is a hydrogen atom, a saturated or unsaturated aliphatic or cycloaliphatic radical, an optionally substituted aromatic radical or araliphatic radical and each contains up to 12 carbon atoms, and

n is an integer of 0 to 5,

and

D) optionally one or more (cyclo) aliphatic mono-or polyamines of up to 400 molecular weight groups and having 1 to 4 amino groups and optionally one or more polyols of up to 400 molecular weight groups and having 1 to 4 hydroxyl groups, if appropriate also amino alcohols,

and the reaction is carried out in the presence of:

E) one or more catalysts selected from the group consisting of,

F) if desired auxiliaries and additives, and

G) optionally a solvent.

To obtain the polyisocyanates according to the invention, all compounds having organic isocyanate groups, preferably aliphatic, cycloaliphatic, aromatic or heterocyclic polyisocyanates having an NCO functionality of 2 or more, are used as component A) alone or in any mixture with one another.

The compounds of component A) preferably have an average NCO functionality of 2.0 to 5.0, preferably 2.3 to 4.5, an isocyanate group content of 5.0 to 27.0% by weight, preferably 14.0 to 24.0% by weight, and a diisocyanate monomer content of preferably less than 1% by weight, preferably less than 0.5% by weight.

Diisocyanates suitable for preparing the compounds of component A) are diisocyanates or triisocyanates having a molecular weight of 140 to 400 which are obtainable by phosgenation or by phosgene-free processes, for example by thermal decomposition of urethanes, and which carry aliphatically, cycloaliphatically, araliphatically and/or aromatically attached isocyanate groups, for example 1, 4-diisocyanatobutane, 1, 5-diisocyanatopentane, 1, 6-diisocyanatohexane (HDI), 2-methyl-1, 5-diisocyanatopentane, 1, 5-diisocyanato-2, 2-dimethylpentane, 2, 2, 4-or 2, 4, 4-trimethyl-1, 6-diisocyanatohexane, 1, 10-diisocyanatodecane, 1, 3-and 1, 4-diisocyanatocyclohexane, 1, 3-and 1, 4-bis (isocyanatomethyl) cyclohexane, 1-isocyanato-3, 3, 5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), 4, 4 '-diisocyanatodicyclohexylmethane (Desmodur ® W, Bayer AG, Levokusen), 4-isocyanatomethyl-1, 8-octyl diisocyanate (triisocyanatononane, TIN), omega' -diisocyanato-1, 3-dimethylcyclohexane (H6XDI), 1-isocyanato-1-methyl-3-isocyanatomethylcyclohexane, 1-isocyanato-1-methyl-4-isocyanatomethylcyclohexane, bis (isocyanatomethyl) norbornane, 1, 5-naphthalene diisocyanate, 1, 3-and 1, 4-bis- (2-isocyanato-2-propyl) benzene (TMXDI), 2, 4-and 2, 6-diisocyanatotoluene (TDI) especially the 2, 4 and 2, 6-isomers and technical grade mixtures of these two isomers, 2, 4 'and 4, 4' -diisocyanatodiphenylmethane (MDI), 1, 5-diisocyanatonaphthalene, 1, 3-bis (isocyanatomethyl) benzene (XDI) and any mixtures of the compounds mentioned.

Suitable compounds for use as component A) are polyisocyanates which are obtained by reaction of di-or triisocyanates themselves with isocyanate groups, such as uretdiones (uretdiones) or carbodiimide compounds or such as isocyanurates or iminooxadiazinediones (iminooxadiazinediones), which are formed by reaction of three isocyanate groups. Likewise, the polyisocyanates may contain monomeric di-and/or triisocyanates and/or oligomeric isocyanates having biuret, allophanate and acylurea structural units, monomeric di-and triisocyanates with low monomer content or partial modification, and any mixtures of the polyisocyanates mentioned. Also very suitable are polyisocyanate prepolymers having an average of more than one isocyanate group per molecule. They are obtained by pre-reacting a molar excess of, for example, one of the polyisocyanates mentioned above with an organic material having at least two active hydrogen atoms per molecule, for example in the form of hydroxyl groups.

Particularly preferred polyisocyanates of component A) are those which contain uretdione, isocyanurate, acylurea, biuret, allophanate or iminooxadiazinedione and/or oxadiazinetrione structures (see also J.Prakt. chem.336(1994) page 185-200) and those which are based on the abovementioned diisocyanates, in particular aliphatic and/or cycloaliphatic diisocyanates.

Very particularly preferred for use in component A) are polyisocyanates or polyisocyanate mixtures of the above-mentioned kind having exclusively aliphatically and/or cycloaliphatically attached isocyanate groups, in particular based on 1, 6-Hexamethylene Diisocyanate (HDI), isophorone diisocyanate (IPDI) and/or 4, 4' -diisocyanatodicyclohexylmethane.

Suitable compounds of component B) are compounds which are hydrophilicized nonionically (type B1) and/or ionically or potentially ionically (type B2) and have groups which are reactive toward isocyanates, and which can be used individually or in any desired mixtures with one another.

Nonionically hydrophilicizing compounds b1) are, for example, monopolyalkylene oxide polyether alcohols having a number average of from 5 to 70, preferably from 7 to 55, ethylene oxide units per molecule and containing at least 30% by weight of ethylene oxide units, such as are obtainable in a known manner by alkoxylation of suitable starter molecules (as described, for example, in Ullmanns Encyclopadie dertechnischen Chemie, 4 th edition, volume 19, Chemie Press, Weinheim, pages 31 to 38).

Suitable starter molecules are, for example, saturated monoalcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, the various isomeric pentanols, hexanols, octanols and nonanols, n-alcohol, n-dodecanol, n-tetradecanol, n-hexadecanol, n-octadecanol, cyclohexanol, the various isomeric methylcyclohexanols or hydroxymethylcyclohexane, 3-ethyl-3-hydroxymethyloxetane or tetrahydrofurfuryl alcohol; diethylene glycol monoalkyl ethers such as diethylene glycol monobutyl ether; unsaturated alcohols such as allyl alcohol, 1, 1-dimethylallyl alcohol or oleyl alcohol, aromatic alcohols such as phenol, the isomeric cresols or methoxyphenols, arylaliphatic alcohols such as benzyl alcohol, anisyl alcohol or cinnamyl alcohol; secondary monoamines such as dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, bis- (2-ethylhexyl) amine, N-methylcyclohexylamine and N-ethylcyclohexylamine or dicyclohexylamine and heterocyclic secondary amines such as morpholine, pyrrolidine, piperidine or 1H-pyrazole.

Preferred starter molecules are saturated monoalcohols and also diethylene glycol monoalkyl ethers. Particular preference is given to using diethylene glycol monobutyl ether as starter molecule.

Alkylene oxides which are particularly suitable for the alkoxylation reaction are ethylene oxide and propylene oxide, which can be used in any order or else in a mixture in the alkoxylation reaction.

Preferred so-called polyalkylene oxide polyether alcohols are pure polyethylene glycol polyethers or mixtures of polyalkylene oxide polyethers, and whose alkylene oxide units consist of at least 30 mol%, preferably at least 40 mol%, of ethylene oxide units.

Particularly preferred nonionically hydrophilicizing compounds b1) are monofunctional mixed polyalkylene oxide polyethers which have at least 40 mol% ethylene oxide units and a maximum of 60 mol% propylene oxide units.

Ionically or potentially ionically hydrophilicizing compounds B2) of component B) are to be understood as meaning all those having at least one isocyanate-reactive group and at least one functionality (e.g. -COOY, -SO)₃Y，-PO(OY)₂(Y＝H，NH₄ ⁺Metal cations), -NR₂，-NR₃ ⁺(R ═ H, alkyl, aryl)) and which, upon interaction with aqueous media, give rise to a dissociation equilibrium which may be determined by pH and may therefore be negatively, positively or neutrally charged.

Preferred compounds are mono-or di-hydroxy functional carboxylic, sulfonic or phosphonic acids, mono-or di-amino functional carboxylic, sulfonic or phosphonic acids, which may be present as internal salts (zwitterions, betaines, ylium salts) or as metal or ammonium salts. Examples of ionically or potentially ionically hydrophilicizing compounds are dimethylolpropionic acid, hydroxypivalic acid, dihydropivalic acid,N- (2-aminoethyl) -beta-alanine, 2- (2-aminoethylamino) ethanesulfonic acid, ethylenediamine propanesulfonic acid or ethylenediamine butanesulfonic acid, 1, 2-or 1, 3-propanediamine-beta-ethanesulfonic acid, lysine, 3, 5-diaminobenzoic acid, hydrophilizing agents as in example 1 of EP-A0916647 and alkali metal salts and/or ammonium salts thereof; addition product of sodium bisulfite to butene-2-diol-1, 4-, addition product of alcohol-1, 4-polyether sulfonate, 2-butanediol and NaHSO₃(for example of the formula I-III described in DE-A2446440, pages 5 to 9) and compounds which contain structural units which can be converted into cationic groups, such as amine-based structural units, for example N-methyldiethanolamine, as hydrophilic structural components. It is additionally possible to use CAPS (cyclohexylaminopropanesulfonic acid), as component B2, in component B), as employed in WO 01/88006.

Ionically or potentially ionically hydrophilicizing compounds which are particularly preferably used in component b2) are N- (2-aminoethyl) - β -alanine, 2- (2-aminoethylamino) ethanesulfonic acid, dimethylolpropionic acid, hydrophilicizing agents as in example 1 of EP-A0916647, and also metal or ammonium salts thereof.

Component B) is preferably a composition composed of nonionically and ionically or potentially ionically hydrophilicizing compounds of the above-mentioned type, particularly preferably a combination of nonionically and anionically hydrophilicizing compounds.

Used as blocking agents in component C) are CH-acidic cyclic ketones of the formula (2),

wherein the content of the first and second substances,

x represents an electron-withdrawing group,

R¹，R²independently of one another, is a hydrogen atom, a saturated or unsaturated aliphatic or cycloaliphatic radical, an optionally substituted aromatic radical or araliphatic radical and each contains up to 12 carbon atoms, and

n is an integer of 0 to 5.

The electron-withdrawing groups X may be all those substituents which, for example, by meso and/or inductive effects, lead to CH acidity from the alpha-hydrogen. These groups may be, for example, ester groups, sulfoxide groups, sulfone groups, nitro groups, phosphonate groups, nitrile groups, isonitrile groups or carbonyl groups. Preferred are nitrile groups and ester groups, particularly preferred are methyl carboxylate and ethyl carboxylate groups.

Also suitable are compounds of the general formula (2) which optionally contain heteroatoms such as oxygen, sulfur or nitrogen atoms in the ring. Of these, the structural form of the lactone is preferred.

Preferred active ring systems of formula (2) are 5(n ═ 1) and 6(n ═ 2) membered rings.

Preferred compounds of the general formula (2) are cyclopentanone-2-carboxymethylester and cyclopentanone-2-carboxyethylester, cyclopentanone-2-carbonitrile, cyclohexanone-2-carboxymethylester and cyclohexanone-2-carboxyethylester or cyclopentanone-2-carbonylmethane. Particular preference is given to cyclopentanone-2-carboxymethylester and cyclopentanone-2-carboxyethylester and cyclopentanone-2-carboxymethylester and cyclopentanone-2-carboxyethylester.

It is clear that those CH-acidic cyclic ketones mentioned in component C) can be used in admixture with one another and optionally with other blocking agents. Further suitable blocking agents are, for example, alcohols, lactams, oximes, malonates, alkyl acetoacetates, triazoles, phenols, imidazoles, pyrazoles and amines, such as butanone oxime, diisopropylamine, 1, 2, 4-triazole, dimethyl-1, 2, 4-triazole, imidazole, diethyl malonate, ethyl acetoacetate, acetoxime, 3, 5-dimethylpyrazole, epsilon-caprolactam, N-methylbenzylamine, N-ethylbenzylamine, N- (iso) propylbenzylamine, N-N-butylbenzylamine, N-isobutylbenzylamine, N-tert-butylbenzylamine or 1, 1-dimethylbenzylamine, N-alkyl-N-1, 1-dimethylmethylaniline, adducts of benzylamine on compounds having an activated double bond, such as malonates, N-dimethylaminopropylbenzylamine and other tertiary amino-containing and optionally substituted benzylamines and/or dibenzyls Amines or any mixture of these blocking agents. If used predominantly in combination, the amount of further blocking agents in component C) other than CH-acidic cyclic ketones can be up to 80% by weight, preferably up to 60% by weight, very particularly preferably up to 20% by weight, based on the total component C).

It is particularly preferred to use exclusively cyclopentanone-2-carboxyethyl ester as component C).

At least 50% by weight, preferably at least 60% by weight and very preferably at least 70% by weight of the isocyanate groups of the polyisocyanates according to the invention are present in blocked form by the compounds of component C).

As component D), it is possible to use other mono-, di-, tri-and/or tetrafunctional components which are reactive toward isocyanates, alone or in a mixture with one another. They may be mono-, di-, tri-and/or tetra-amino-or hydroxy-functional substances having a molecular weight of not more than 400g/mol, such as ethylenediamine, 1, 2-or 1, 3-diaminopropane, 1, 3-, 1, 4-and 1, 6-diaminohexane, 1, 3-diamino-2, 2-dimethylpropane, 1-amino-3, 3, 5-trimethyl-5-aminoethylcyclohexane (IPDA), 4, 4 ' -diaminodicyclohexylmethane, 2, 4-and 2, 6-diamino-1-methylcyclohexane, 4, 4 ' -diamino-3, 3 ' -dimethyldicyclohexylmethane, 1, 4-bis- (2-amino-prop-2-yl) -cyclohexane, ethylene glycol, propylene glycol, 1, 4-butanediol, 1, 6-hexanediol, glycerol, trimethylolethane, trimethylolpropane, the various isomeric hexanetriols, pentaerythritol or any desired mixtures of these compounds.

As compounds of component E) there may be used, alone or in any mixture, all compounds known to the skilled worker in NCO-blocking catalysis. Suitable preference is given to alkali metal bases and alkaline earth metal bases, such as powdered sodium carbonate (soda) or trisodium phosphate, metal salts, in particular carbonates of the second subgroup, in particular zinc, and tertiary amines, such as DABCO (1, 4-diazabicyclo [2.2.2] octane).

Preferred compounds which can be used in component E) are sodium carbonate, potassium carbonate or zinc salts, in particular zinc 2-ethylhexanoate.

As component F) which may be used if desired, auxiliaries or additives or mixtures thereof may be included. Compounds suitable for F) are, for example, antioxidants such as 2, 6-di-tert-butyl-4-methylphenol, UV absorbers of the 2-hydroxyphenylbenzotriazole type or light stabilizers of the HALS compound type or other commercially available stabilizers, such as those described in "Lichtschuttmitt fur Lacke" (A.Valet, Vincentz Press, Hannover, 1996) and "Stabilization of polymeric Materials" (H.Zweifel, Springer Press, Berlin, 1997, appendix 3, page 181-.

Suitable as organic solvents G) are the customary coating solvents, such as ethyl acetate, butyl acetate, 1-methoxypropyl-2-acetate, 3-methoxy-n-butyl acetate, acetone, 2-butanone, 4-methyl-2-pentanone, cyclohexanone, toluene, xylene, chlorobenzene or mineral spirits. Especially mixtures containing aromatic compounds of higher degree of substitution, such as those sold under the trade name Solvent Naphtha, Solvent so^®(Exxon Chemicals，Houston，USA)，Cypar^®(Shell Chemicals，Eschborn，DE)，Cyclo Sol^®(ShellChemicals，Eschborn，DE)，Tolu Sol^®(Shell Chemicals，Eschborn，DE)，Shellsol^®(Shell Chemicals, Eschborn, DE) are also suitable. Other solvents are, for example, carbonates such as dimethyl carbonate, diethyl carbonate, 1, 2-ethylene carbonate and 1, 2-propylene carbonate, lactones such as beta-propiolactone, gamma-butyrolactone, epsilon-caprolactone, epsilon-methylhexalactone, propylene diacetate, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, diethylene glycol ethyl acetate and-butyl ether acetate, N-methylpyrrolidone and N-methylcaprolactam or mixtures of any of these solvents. Preferred solvents are acetone, 2-butanone, 1-methoxypropyl-2-acetate, xylene, toluene, mixtures containing important aromatic compounds of higher degree of substitution, such as those commercially available under the trade names Solvent Naphtha, Solvent sso^®(Exxon Chemicals，Houston，USA)，Cypar^®(ShellChemicals，Eschborn，DE)，Cyclo Sol^®(Shell Chemicals，Eschborn，DE)，Tolu Sol^®(Shell Chemicals，Eschborn，DE)，Shellsol^®(Shell Chemicals, Eschborn, DE), and N-methylpyrrolidone. Particular preference is given to acetone, 2-butanone and N-methylpyrrolidone.

The process of the invention is preferably carried out at a temperature of from 15 ℃ to 140 ℃, particularly preferably from 40 to 90 ℃.

In the process of the invention, the components A), B), C) and, if desired, D) can be reacted with one another in any desired sequence in the presence of the catalyst E) and, if desired, also in the presence of the component F) and, if desired, in the solvent G).

In a preferred embodiment of the invention, B) contains not only nonionic (corresponding to B1)) but also ionically or potentially ionically (corresponding to B2)) hydrophilicizing compounds and the preparation of the polyisocyanates according to the invention is carried out in such a way that A) is first mixed with compounds of the B1) type and, if desired, components D), F) and G). The reaction mixture is subsequently reacted with a blocking agent C) in the presence of a catalyst E), and then with a compound of type b 2).

In another preferred embodiment of the invention, B) contains compounds according to B1) and B2), the latter containing at least one hydroxyl group as isocyanate-reactive group and no amino function. The polyisocyanates according to the invention are prepared by mixing A) with hydrophilicizing compounds b1) and b2) and, if desired, components D), F) and G). The reaction mixture is subsequently reacted with a blocking agent C) in the presence of a catalyst E).

In the process of the invention, preferably from 40 to 80% by weight of component A), from 1 to 40% by weight of component B), from 15 to 60% by weight of component C) and from 0 to 30% by weight of component D) are used, where the sum of A to D) amounts to 100% by weight.

In the process of the invention, more preferably from 45 to 75% by weight of component A), from 1 to 35% by weight of component B), from 20 to 50% by weight of component C) and from 0 to 20% by weight of component D) are used, where the sum of A to D) amounts to 100% by weight.

In the process of the invention, it is very particularly preferred to use from 50 to 70% by weight of component A), from 3 to 30% by weight of component B), from 25 to 45% by weight of component C) and from 0 to 10% by weight of component D), where the sum of A to D) amounts to 100% by weight.

The hydrophilicized blocked polyisocyanates may optionally also contain stabilizers and further auxiliaries E) and optionally organic solvents F). The stabilizers and/or auxiliaries E) are used in amounts of from 0 to 25% by weight, preferably from 0 to 15% by weight, particularly preferably from 0 to 5% by weight, based on the reaction products of A) to D), and the organic solvents F) are used in amounts of from 0 to 30% by weight, preferably from 0 to 20% by weight, particularly preferably from 0 to 10% by weight.

It is particularly preferred not to use solvent G).

The polyisocyanates according to the invention can be used, for example, for the production of paints, coatings, sizes, adhesives and moldings.

A further subject matter of the present invention is aqueous solutions or dispersions of the polyisocyanates according to the invention and a process for their preparation, in which the hydrophilic polyisocyanates according to the invention are mixed with water or aqueous solvents.

The aqueous systems of the blocked polyisocyanates have a solids content of from 10 to 70% by weight, preferably from 20 to 60% by weight and particularly preferably from 25 to 50% by weight, and the amount of organic solvent G) optionally contained is less than 15% by weight, preferably less than 10% by weight and particularly preferably less than 5% by weight. The organic solvent G) optionally contained can be removed, for example, by distillation.

Finally, the invention relates to a coating composition comprising, and to a method for producing such a coating agent,

a) one or more polyisocyanates of the invention,

b) one or more film-forming resins selected from the group consisting of,

c) optionally a catalyst, which is added to the reaction mixture,

d) optionally, a solvent, water,

e) if desired, auxiliaries and additives, which are,

in this process the components a) to e) can be mixed with one another in any desired order.

Suitable as film-forming resins b) are functionalized polymers which are dispersible, emulsifiable, soluble or dispersible in water. Examples are polyester polymers or polyester polymers containing epoxy groups, polyurethanes, acrylic polymers, vinyl polymers such as polyvinyl acetate, polyurethane dispersions, polyacrylate dispersions, polyurethane polyacrylate hybrid dispersions, polyvinyl ether or polyvinyl ester dispersions, polystyrene or polyacrylonitrile dispersions, which can be used in mixtures, also in mixtures with other blocked polyisocyanates and amino crosslinker resins, such as melamine resins. The solids content of the film-forming resins is preferably from 10 to 100% by weight, particularly preferably from 30 to 100% by weight.

The film-forming resins b) may have NCO-reactive groups, such as carboxylic acid groups or alcohol groups, and may therefore be crosslinked together with the polyisocyanates of the invention. If the film-forming resin does not contain NCO-reactive groups, the binder or size or coating agent may not be reactive with the substrate to which it is applied.

Suitable catalysts c) for crosslinking are all catalysts known to the person skilled in the art in the field of isocyanate addition reactions, such as dibutyltin Dilaurate (DBTL), triethylamine, 1, 4-diazabicyclo- [2, 2, 2] -octane, dibutyltin dioctoate or dibutyltin dilaurate. Preference is given to dibutyltin dilaurate.

These catalysts c) are generally used in amounts of from 0 to 5% by weight, preferably from 0.05 to 2% by weight, particularly preferably from 0.1 to 1.5% by weight, based on the total amount of coating agent.

Another subject of the invention is a coating obtainable from the coating composition of the invention.

The coating composition of the present invention may be applied to the substrate by any method, such as dipping, spraying, roll coating, flow coating.

Suitable substrates for coating are, for example, metals, wood, glass fibers, carbon fibers, stone, ceramic minerals, concrete, various plastics, textiles, leather, paper, hard fibers, straw or asphalt, where appropriate also a primer is applied before coating with the coating compositions according to the invention. Preferred substrates are plastics, glass fibres, carbon fibres, metals, textiles and leather.

The coating composition of the invention is preferably cured in a baking time of 15 to 30 minutes and at a temperature of 100 to 200 ℃, preferably 110 to 180 ℃. The baking time depends in particular on the amount of catalyst used. The baking is preferably carried out at a temperature of 110-140 c within 30 minutes.

Examples

All percentages in the following examples are by weight (wt%).

The NCO content was determined by titration in accordance with DIN EN ISO 11909 (titration with dibutylamine).

Example 1

21.9g of a monofunctional Polyether starting from N-butanol and based on ethylene oxide/propylene oxide (approximately 85: 15), having an average molar mass of 2250(OHZ ═ 25) (Polyether LB 25, Bayer AG, Leverkusen, DE), 125.5g of a polyisocyanate containing isocyanate groups and based on 1, 6-diisocyanatohexane (HDI) having an NCO content of 21.8% (HDI-polyisocyanate with isocyanurate structure, viscosity 3200mPas, Desmodur ® N3300, Bayer AG, Leverkusen) and 0.25g of zinc ethylhexanoate were added and heated to 50 ℃ with stirring. 75.8g of cyclopentanone-2-carboxyethyl ester are then added over the course of 30 minutes. After the addition, stirring is carried out for a further 20 minutes at 50 ℃ and 7.0g of an adduct of hydrazine with a molecular weight of 236, consisting of 1 mol of hydrazine hydrate and 2 mol of propylene carbonate, are weighed in and stirred until the theoretical NCO value is reached. A solution consisting of 17.4g of AAS solution (Bayer AG, DE, Leverkusen, 45% strength aqueous solution of the sodium salt of 2- (2-aminoethylamino) ethanesulfonic acid, Bayer AG, Leverkusen, DE) and 121.9g of water is then metered in over 10 minutes and the reaction mixture is stirred for a further 5 minutes. Dispersion was achieved by adding 420.8g of water (T ═ 60 ℃) over 10 minutes. Stirring for 2h to obtain a dispersion with a solid content of 30.0%.

Example 2

21.9g of a monofunctional Polyether starting from n-butanol and based on ethylene oxide/propylene oxide (approx.85: 15) having an average molar mass of 2250(OHZ ═ 25) of Polyether LB 25, Bayer AG, Leverkusen, DE) (125.5 g of an NCO content of 21.8% (HDI-polyisocyanate with isocyanurate structure, viscosity of 3200mPas, Desmodur) were added^®N3300, Bayer AG, Leverkusen) based on 1, 6-diisocyanatohexane (HDI) and 0.15g of zinc ethylhexanoate and heated to 50 ℃ with stirring. 75.8g of cyclopentanone-2-carboxyethyl ester are then added over the course of 30 minutes. After the addition, stirring is carried out for a further 20 minutes at 50 ℃ and 7.0g of an adduct of hydrazine with a molecular weight of 236, consisting of 1 mol of hydrazine hydrate and 2 mol of propylene carbonate, are weighed in and stirred until the theoretical NCO value is reached. A solution consisting of 18.3g of AAS solution (Bayer AG, DE, Leverkusen, 45% strength aqueous solution of the sodium salt of 2- (2-aminoethylamino) ethanesulfonic acid, Bayer AG, Leverkusen, DE) and 146.0g of water is then metered in over the course of 10 minutes, and the reaction mixture is stirred for a further 5 minutes. Dispersion was achieved by adding 400.0g of water (T ═ 60 ℃) over 10 minutes. Stirring for 2h to obtain a dispersion with a solid content of 30.0%.

Example 3

21.3g of a monofunctional Polyether starting from N-butanol and based on ethylene oxide/propylene oxide (approx.85: 15) having an average molar mass of 2250(OHZ ═ 25) (Polyether LB 25, Bayer AG, Leverkusen, DE), 121.6g of an isocyanate group-containing polyisocyanate having an isocyanurate structure, having an HDI polyisocyanate viscosity of 3200mPas, Desmodur ® N3300, Bayer AG, Leverkusen) and based on 1, 6-diisocyanatohexane (HDI), and 0.12g of zinc ethylhexanoate were added and heated to 50 ℃ with stirring. 73.4g of cyclopentanone-2-carboxyethyl ester were then added over 30 minutes. After the addition, stirring is carried out for a further 20 minutes at 50 ℃ and 7.0g of an adduct of hydrazine with a molecular weight of 236, consisting of 1 mol of hydrazine hydrate and 2 mol of propylene carbonate, are weighed in and stirred until the theoretical NCO value is reached. A solution of 15.5g of the hydrophilizing agent KV1386 (40% aqueous sodium salt of N- (2-aminoethyl) -beta-alanine, BASF AG, Ludwigshafen, DE) and 108.4g of water is then metered in over the course of 10 minutes, and the reaction mixture is stirred for a further 5 minutes. Dispersion was achieved by adding 417.2g of water (T ═ 60 ℃) over 10 minutes. Stirring for 2h to obtain a dispersion with a solid content of 30.0%.

Example 4

23.6g of a monofunctional Polyether starting from n-butanol and based on ethylene oxide/propylene oxide (approximately 85: 15), having an average molar mass of 2250(OHZ ═ 25) (Polyether LB 25, Bayer AG, Leverkusen, DE), 18.9g of a Polyether sulfonate (OHZ ═ 263, polypropylene oxide diol, average molecular weight: 426g/mol, Bayer AG, DE) were added, 135.1g of an HDI polyisocyanate having an NCO content of 21.8% (HDI polyisocyanate having an isocyanurate structure, viscosity of 3200mPas, Desmodur^®N3300, Bayer AG, levikusen) based on 1, 6-diisocyanatohexane (HDI) and 0.28g of zinc ethylhexanoate and heated to 50 ℃ with stirring. 81.6g of cyclopentanone-2-carboxyethyl ester are then added over the course of 30 minutes. After the addition, stirring is carried out for a further 20 minutes at 50 ℃ and 7.0g of an adduct of hydrazine with a molecular weight of 236, consisting of 1 mol of hydrazine hydrate and 2 mol of propylene carbonate, are weighed in and stirred until the theoretical NCO value is reached. Dispersion was achieved by adding 622.4g of water (T ═ 60 ℃) over 10 minutes. Stirring was continued for 2h to give a dispersion with a solids content of 29.9%.

Example 5

25.3g of a monofunctional Polyether starting from n-butanol and based on ethylene oxide/propylene oxide (approx.85: 15), having an average molar mass of 2250(OHZ ═ 25) (Polyether LB 25, Bayer AG, Leverkusen, DE), 6.4g of dimethylolpropionic acid, 144.8g of an NCO content of 21.8% (HDI-polyisocyanate with isocyanurate structure, viscosity of 3200mPas, Desmodur)^®N3300, Bayer AG, Leverkusen) based on 1, 6-diisocyanatohexane (HDI) and 0.29g of zinc ethylhexanoate and heated to 50 ℃ with stirring. 87.4g of cyclopentanone-2-carboxyethyl ester are then added over the course of 30 minutes. After the addition, stirring is carried out for a further 20 minutes at 50 ℃ and 8.1g of an adduct of hydrazine with a molecular weight of 236, consisting of 1 mol of hydrazine hydrate and 2 mol of propylene carbonate, are weighed in and stirred until the theoretical NCO value is reached. 4.6g of triethylamine are then added and stirred for a further 10 minutes at 50 ℃. Dispersion was achieved by adding 634.4g of water (T ═ 60 ℃) over 10 minutes. Stirring for 2h to obtain a dispersion with a solid content of 30.0%.

Example 6

67.7g (0.35 equivalent) of an HDI polyisocyanate having an NCO content of 21.8% (HDI polyisocyanate having isocyanurate structure, viscosity 3200mPas, Desmodur) were introduced with mechanical stirring^®N3300, Bayer AG, Leverkusen) based on 1, 6-diisocyanatohexane (HDI) and 34mg of zinc 2-ethylhexanoate (Octa-Soligen)^®Zink, Borchers Gmb H, Monheim, DE) was placed in a 250mL three-necked flask and dissolved in 20.5g (80% solids) of methoxypropyl acetate. To this solution, 40.5g (0.259 eq) of cyclopentanone-2-carboxyethyl ester were carefully added dropwise while stirring was continued so that the reaction temperature did not exceed 40 ℃. After the desired NCO value (2.97%) had been reached, 20.1g (0.091 eq) of CAPS (cyclohexylaminopropanesulfonic acid, Raschig, DE) and 11.6g (0.091 eq) of dimethylcyclohexylamine were added and stirred at 80 ℃ until a clear solution was obtained, the system was adjusted to a solids content of 70% with methoxypropyl acetate before dispersing was carried out. The hydrophilicized polyisocyanates thus obtained are dispersed in water to form a stable 40%The dispersion of (4).

The mechanical properties of the hydrophilicized blocked polyisocyanates according to the invention are determined on free films. To produce free films, hydrophilicized blocked polyisocyanates are mixed with the film-forming resins. The mixture is prepared from 60 wt% Baybond^®PU 401 (anionic-nonionic PUR dispersion with a solids content of 40%, average particle diameter of 100-300nm, Bayer AG, DE (film-forming resin)) and 40% by weight of the hydrophilicized blocked polyisocyanates according to the invention.

The free film is prepared from the mixture by the following method: in a stretch film-making machine consisting of two precisely adjustable-spacing burnishing rolls, a release paper is inserted before the back roll. The spacing between the sheet and the front roller is adjusted with a feeler gauge. This spacing corresponds to the film thickness (wet) of the resulting coating, and the desired thickness of each coating can be adjusted. It is also possible to apply the coating in a plurality of layers in succession. For the application of the individual layers, the product (previously prepared as an aqueous preparation by adjusting the viscosity to 4500mPas by adding ammonia/polyacrylic acid) was poured into the gap between the paper and the front roller, and the release paper was pulled vertically downwards, while the corresponding film was also formed on the paper. If multiple layers are applied, each layer is dried and the paper is re-inserted.

The 100% modulus was determined on films according to DIN 53504, resulting in a thickness of > 100. mu.m.

The mean particle size (in number average) of the PUR dispersions was determined by means of laser coherence spectroscopy (apparatus: Malvern Zetasizer 1000, Malverr Inst. Limited).

	Mixture 1	Mixture 2
			Film-forming resin 2): part of curing agent 1): preparation of parts average particle size dry condition mixture tensile test: 0 value 100% modulus [ MPa ]]Tensile strength [ MPa ]]Elongation at break [% ]]	Baybond ® PU 40160% by weight of the dispersion of example 1 (inventive) 40% by weight of 156nm10 min, 1) to 2) being added at 125 ℃; stirring at room temperature for 5 minutes 0.65.51140	Baybond ® PU 40177% by weight of the dispersion of example 2 (inventive) 23% by weight of 159nm10 min, 1) to 2) being added at 125 ℃; stirring at room temperature for 5 minutes 2.830.01150

Drying at 25 ℃ for 24h and films similarly prepared from mixtures 1 and 2 were very sticky and their mechanical properties were not measurable. The film test results shown in table 1 show that the film was already crosslinked at the lower drying temperature of 125 c.

Claims (7)

1. A polyisocyanate having

i) Nonionic hydrophilicizing groups based on polyalkylene oxide polyethers having at least 30% by weight of ethylene oxide units, and/or

ii) ionically or potentially ionically hydrophilicizing groups comprising: -COOY, -SO₃Y，-PO(OY)₂，-NR₂，-NR₃ ⁺Wherein Y is H, NH₄ ⁺Metal cations, R ═ H, alkyl groups, aryl groups, which, upon interaction with water, form a pH-dependent dissociation equilibrium,and therefore will be neutral or positively or negatively charged depending on the pH, and

iii) at least one structural unit of the formula (1),

wherein the content of the first and second substances,

x is an ester group, a sulfoxide group, a sulfone group, a nitro group, a phosphonate group, a nitrile group, an isonitrile group or a carbonyl group,

R¹，R²independently of one another, are a hydrogen atom, a saturated or unsaturated aliphatic or cycloaliphatic radical, an aromatic or araliphatic radical which is optionally substituted, and which each contain up to 12 carbon atoms, and

n is an integer of 0 to 5.

2. A process for preparing the polyisocyanates according to claim 1, in which the following are reacted with one another:

A) one or more organic polyisocyanates, and

B) one or more organic compounds having at least one isocyanate-reactive group comprising

b1) Based on nonionic hydrophilicizing groups of polyalkylene oxide polyethers which contain at least 30% by weight of ethylene oxide units,

and/or

b2) Ionically or potentially ionically hydrophilizing groups comprising: -COOY, -SO3Y, -PO (OY)₂，-NR₂，-NR₃ ⁺Wherein Y is H, NH₄ ⁺Metal cations, R ═ H, alkyl groups, aryl groups, which, upon interaction with water, form a pH-dependent dissociation equilibrium and are therefore neutral or positively or negatively charged depending on the pH,

C) one or more blocking agents containing at least one CH-acidic cyclic ketone having the general formula (2),

wherein the content of the first and second substances,

x is an ester group, a sulfoxide group, a sulfone group, a nitro group, a phosphonate group, a nitrile group, an isonitrile group or a carbonyl group,

R¹，R²independently of one another, is a hydrogen atom, a saturated or unsaturated aliphatic or cycloaliphatic radical, an optionally substituted aromatic radical or araliphatic radical and each of which contains up to 12 carbon atoms, and

n is an integer of 0 to 5,

and

D) optionally one or more aliphatic or cycloaliphatic mono-or polyamines having 1 to 4 amino groups in the molecular weight range up to 400 and optionally one or more polyols having 1 to 4 hydroxyl groups in the molecular weight range up to 400 and, where appropriate, amino alcohols,

and the reaction is carried out in the presence of

E) One or more catalysts selected from the group consisting of,

F) if desired auxiliaries and additives, and

G) optionally a solvent.

3. Use of the polyisocyanates according to claim 1 for the production of paints, coatings, sizes, adhesives and moldings.

4. An aqueous solution or dispersion of the polyisocyanate of claim 1.

5. A coating composition comprising:

a) one or more polyisocyanates according to claim 1,

b) one or more film-forming resins selected from the group consisting of,

c) optionally a catalyst, which is added to the reaction mixture,

d) optionally a solvent, and

e) optionally auxiliaries and additives.

6. A coating obtained from the coating composition of claim 5.

7. A substrate coated with the coating of claim 6.