CA2230827A1 - Dispersions comprising polyurethanes having carbonyl groups in keto function - Google Patents

Abstract

The invention concerns aqueous dispersions containing a polyurethane (A), containing structural units derived from compounds of formula (I), in which the substituents have the following meanings: R1, R2, R3 each designate hydrogen, C1-C24 alkyl or C6 - C24 alkenyl; R4 designates hydrogen; R5, R6 a) together designate C4-C10 alkane-diyl, b) each designate C2-C10 alkyl, C5-C8 cycloalkyl or C7-C20 aralkyl, c) each designate a hydroxyl-terminated poly(C2C4 alkylene oxide), or d) designate an R5 or R6 group with the meaning given in (a) to (c) and the other group designating hydrogen or a group of formula (II), in which X designates C2-C6 alkane-diyl; and R7 has the same meaning as R5 or R6 with the exception that R7 is not a group of formula II, R5 and R6 carrying a total of between 2 and 5 hydroxyl groups bonded to aliphatic carbon atoms; and R5 and/or R6 optionally carrying 1 or 2 aromatically bonded hydroxyl groups or 1 nitrile, tertiary amino, carboxylic acid or sulphonic acid group which are optionally present in the form of their salts.

Description

0050/41;229 Dispersions comprising polyurethanes having carbonyl groups in keto function The present invention relates to aqueous dispersions comprising a polyurethane (A) including structural units derived from compoùnds of the formula (I) R1R2CH - C CR3R4 - C NRsR6 Il 11 O O

where R1, R2 ,and R3 are each hyclrogen, C1-C24-alkyl or C6-C24-alkenyl, R4 is hydrogen, R5 and R6 a) together ar~e C4-C10-a1k~ne~iyl, ~) are each C2--C10-alkyl, C5-C8-cycloalkyl or C7-C20-aralk:yl, c) are each a :hydroxyl-terminated poly(C2-C4-alkylene oxide), or d) one radical, R5 or R6, is as defined under (a) to ~c) and the other radical is hydrogen or is of the formula II

RlR2CH C CR3R4 - C 1 X II
11 ll O O

where 45 X is C2-C6-alkanediyl and R7 is as defined for Rs or R6 but is not of the formula II, and - Rs and R6 carry a tota~l of 2-5 hydroxyls attached to an aliphatic carbons [sic~, and - R5 and/or R6 may carry 1 or 2 hydroxyls attached to aromatic structures or may carry one nitrile, tertiary amino, carboxyl or sulfo group in free or salt form.

Aqueous dispersions compri~ing polyurethanes are widely known ~cf. D. G. Oertel ~Kunststoff Handbuch 7", 2nd Edition, 1983, 15 Carl Hanser Verlag, Municlh, Vienna, pp. 24-25 and 571-574). Also known is the use of the polyurethane dispersions as coating compositions, for example as paints or printing inks.

Processing, economics and the desired properties of the 20 subsequent coatings have combined to impose on the polyurethane dispersions a range of re~quirements which have not yet been fully met.

25 The service properties of surface coatings are frequently subject to the following requirem,ents:

- The coating materials should be able to be stored for a prolonged period without any change in their properties (eg.
rheological properties) or in the properties of the coatings produced using them.

- The coating materials should feature minimized amounts of so]vents, leveling agents or other volatile organic constituents, so as to in; ize the emissions of organic compounds when the cc,ating materials are applied and dried.

- Fo]lowing application, to the workpiece the coating material should rapidly dry or cure so that it can be used or processed further after just a short time.

- The coating materials should show little or no foaming tendency when being processed.

' 0050/41;229 In the case of high-quality coatings and surfaces of polyurethane coating materials, a combination of the following requirements applies:

5 - smooth surface and high gloss - resistance to moisture, water vapor and chemicals, such a~
di;Lute alkalis and ac:ids, and to organic solvents and surfactants - stability toward mechanical stresses such as impact or abrasion 15 - freedom from inherent: color and defects such as bubbles or cracks - in the case of wood substrates, the coating materials should alLow the visible structure of the wood to emerge more st:rongly (bringing out the grain).

The development of coatings having such a combination of propert:ies is made all the more difficult since the individual 25 perfornnance properties appear to be based on divergent structural propert;ies. Whereas a pre!requisite of abrasion resistance is a certain level of hardness, impact strength necessitates a certain elastic:ity. Moreover, a glossy surface requires the coating material to level well, which generally implies the use of 30 volati]Le organic compouncls as leveling agents.

In part;icular, the coating materials should be able to be proces-;ed by as wide a range as possible of customary techniques.
The dil-ferent techniques, of varying complexity (where the 35 complexity correlates wit:h the quality of the resulting coatinqs), are required so as to be able with maximum economic efficiency to produce coatings meeting a defined level of quality; indeed, increased complexity and effort often appear to be jus1;ified only if matc:hed by corresponding quality. On the 40 other hand, it is logistically complex for the coatings processor to stock a different raw material for each processing technique.
Among ~;uch techniques, the following are particularly important:

The te<hnique of cold CUI. ing (curing of the coating at room 45 temperature) with a one-component coating system is the least complex and should satisi-y average quality requirements.

- ' 0050/4~229 The technique of cold curing with a two-component coating system which, since it requires the processor to mix the system and then gives a mixture of only limited pot life, is associated with greater effort on his part, is intended to satisfy heightened 5 quality requirements.

The stoving technique (curing at usually 100-160~C) is suitable for the production of coatings of the highest quality.

Normally, the surface properties of printing inks are subject to the same requirements as already stated for the other coating materials. In addition, it is important that they fulfill further, specific requirements:
- high proportion of solids, especially pigments, in order to minimize drying times, and - good leveling even on nonpolar substrates such as poLyethylene and polypropylene.

Requirements which should be met by articles printed with the inks, especially those articles made of nonpolar plastics, are:
good ink adhesion to the substrate, especially under the inEluence of water - resistance of the inks to customary solvents, fats, oils, su:rfactants, aqueous solutions, acids and alkalis - good fastness properlies.

This set of requirements also gives rise in some cases to 35 conflic:ting aims, and the prior art printing inks fail to resolve this conflict fully. For instance, it is known that the leveling of printing inks can be improved by adding surfactant, but that the applied inks are of cleficient water resistance. By adding solvent: it is likewise possible to improve the wettability, but 40 this limits the ecological advantages of the water-based inks.

Polyurethane dispersions which can be used as one-component system~; for coating various substrates are described in 45 EP-B-0 332 326. In addition to a water-dispersible polyurethane with a molecular weight of more than 2000 which carries carbonyl groups in keto or aldehycle function, they include a further component which carries hydrazine or hydrazone groups, or else s the po]yurethane carries not only the keto or aldehyde carbonyl groups but hydrazine and/or hydrazone groups as well. To introduce the carbonyl ~t:ructural unit into the polyurethane it is recommended that the latter is prepared using monomers such as 5 dihydroxyacetone, the Mic:hael adduct of diacetoneacrylamide with diamine or alkanolamine, or the Michael adduct of 2 mol of diacetoneacrylamide with 2 mol of diamine.

A disadvantage of the dicipersions prepared using 10 dihydroxyacetone, however, is that they produce brown films.

Said document also proposes incorporating keto groups into the polyurethane by using monomers such as the Michael adduct of 15 diacetoneacrylamide and diethanolamine. Although such monomers can indeed be processed 21S one-component systems which lead by cold curing to coatings having satisfactory properties, they are not suitable as a component of two-component systems for producing coatings havinq a superior level of properties. Nor 20 does processing by stoving produce coatings which meet exacting requir~sments .

In addition, aqueous dispersions comprising a water-disp~rsible, carbonyl-containing polyurethane and a polyhydrazide are known 25 from DE-A-3 837 519, in which the carbonyl function enters the polyurethane through the use, during preparation, of carbonyl-containing mono- or polyalcohols, examples being hydroxyacetone, hydroxybenzaldehyde, acetoin, benzoin, adducts of diepoxides and ketocarboxylic acids, and ketocarboxylic esters 30 having at least one hydroxyl. Said document also recommends the use of these dispersions as a coating material or printing ink.

The dispersions which comprise polyurethanes prepared from polyhydroxycarbonyl compounds do not give full satisfaction when 35 shelf life is at a premium.

The mechanical properties and solvent resistance of coatings produced from dispersions comprising a polyurethane which has been prepared from the abovementioned monohydroxycarbonyl 40 compounds are as yet not entirely satisfactory. Moreover, these dispersions have a tendency to form coagulum.

EP-A-0 646 609 likewise recommends the use of polyurethane 45 dispersions as printing inks. Its polyurethanes have terminal hydrazine functional groups and can be dispersed in water owing to the presence of ionic and polyalkylene oxide groups.

JP-A-7'i-98913 discloses polyurethane rubbers which are prepared using amides formed from an alkanolamine and acetic acid (H3CCOC'H2CON(CH2CH2OH)2 or H3CCOCH2CONHC(CH2CH2OH)2C2H5) and an aluminum or iron acetoacetate complex as chain extender.

It is an object of the pr-esent invention, therefore, to provide aqueou~; coating materials with all-round high performance which do not have the deficienc:ies of the prior art and whose proces-;ing to give strong, ~lossy coatings requires the use of lO little or no volatile leveling assistants. In particular, the coatin(~ materials should be able to be employed with maximum flexibility; in other words, the level of properties of the coatin~3s, which can be at:tained using them by various processing techniques, should not be inferior to that of the prior art.

A further object is to provide printing inks which are free from the de~Eiciencies of the prior art and can be used to produce printed substrates, espec:ially nonpolar printed substrates, on 20 which 1:he ink adheres firmly.

We have found that these objects are achieved by the dispersions described above.

25 The dispersions comprise a polyurethane (A) which includes structural units derived from compounds of the formula (I) RlR2CH C CR3R4 --C NRsR6 O O

35 where R1, R2 and R3 are each hydrogen, C1-C24-alkyl or C6-C24-alkenyl, 40 R4 is hydrogen, R5 and R6 generally:

a) together are C4-C10-alkanediyl, preferably butane-1,4-diyl or pentane-1,5-diyl, b) are each C2-C10-alkyl, preferably C2- or C3-alkyl, or are C5-C8-cycloalkyl, preferably cyclopentyl or cyclohexyl, or are C7-C20-aralkyl, preferably benzyl, or are of the formula II

RlR2CH C CR3R4 - C - 1 - X II
Il 11 where 15 X is C2-C6-alkanediyl a.nd R7 i8 as defined for RS or R6 but i8 not of the formula II, c) ar~e each a hydroxyl-terminated poly(C2-C4-alkylene oxide), preferably of the fo:rmula III, I
-ICHz- CH - 0 - H III
\ / n 30 where R8 is hydrogen, methyl ,and/or ethyl and n is 1 to 10, where - Rs and R6 together carry 2 to 5 hydroxyl~ attached to an aliphatic carbon, an,d - R5 and/or R6 may carry 1 or 2 hydroxyls attached to aromatic structures or may carry 1 nitrile, tertiary amino, carboxyl or sulfo group in fr,ee or salt form.

~ 0050/4~229 CA 02230827 1998-03-19 In view of the desired crosslinking density and the mechanical propert:ies dependent thereon, the carbonyl content of the structural elements in the polyurethane which are derived from the compounds of the formula (I) is chosen such that there are in 5 genera]. from 3 to 140 mmol, preferably from 6 to 100 mmol, particularly preferably from 10 to 90 mmol of these groups per 100 g of polyurethane.

The novel aqueous disper~iions are usually prepared by I. preparing a polyurethane by reacting a) polyfunctional isocyanates of 4 to 30 carbons, b) polyols of which bl) 10-100 mol%, based on the overall amount of polyols (b), have a molecular weight of 500-5000, and b2) 0-90 mol%, based on the overall amount of polyol~
~b), are diiunctional and have a molecular weight of 62-500 g/mol, c) compounds of the formula I and/or condensation products which carry alcc,holic hydroxyls and include structural elements derived~ from compounds of the formula (I) (condensates I), d) if desired, furt.her polyfunctional compounds which are different from t.he monomers (b) and (c) and have reactive groups selected from alcoholic hydroxyl, primary amino and secondary amino, and ~5 e) monomers which a~re different from (a), (b), (c) and (d), have at least one isocyanate group or at least one isocyanato-react:ive group and, moreover, carry at least one hydrophilic or potentially hydrophilic group which renders the polyurethane dispersible in water, II. di.spersing the polyurethane resulting from step I in water.

45 Suitable monomers (a) are the polisocyanates customarily employed in polyurethane chemistry.

~ 0050/4b229 Particular mention may be made of diisocyanates X(NC0)2 in which X
is a C4-Cl2 aliphatic, a (6-Cl5 cycloaliphatic or aromatic or a C7-Cl5 araliphatic hydrocarbon radical. Examples of such diisocyanates are tetramethylene, hexamethylene and 5 dodecamethylene diisocyan,ate, 1,4-diisocyanatocyclohexane, l-isocyanato-3,5,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI), 2,2-bis(4-isocyanatocyclohexyl)propane, trimethylhexane diisocyanate, 1,4-diisocy~anatobenzene, 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, 4,4~-diisocyanatodiphenylmethane, 10 tetramethylxylylene diisocyanate (TMXDI), 2,4~-diisocyanatodiphenylmethane, p-xylylene diisocyanate, the isomers of bis(4-isocyanatocyclohexyl)methane, such as the trans/t:rans, the cis/cis and the cis/trans isomers, and mixtures consist:ing of these compounds, especially the mixtures of the 15 respect:ive structural isomers of diisocyanatotoluene and diisocyanatodiphenylmethclne, and in particular the mixture consist:ing of 80 mol% 2~4 diisocyanatotoluene [sicl and 20 mol%
2,6-di:Lsocyanatotoluene. Particular advantage is also possessed by mixlures of aromatic isocyanates, such as 2,4 diisocyanato-20 toluene [sic] and/or 2,6--diisocyanatotoluene, with aliphatic or cycloa:Liphatic isocyanates, such as hexamethylene diisocyanate or IPDI, I?referably in an aliphatic to aromatic ratio of from 4:1 to 1:4.

25 Isocyanates suitable for use as compounds (a) include those which in add:ition to the free isocyanate groups carry further, masked isocyanate groups, for example uretdione or carbodiimide groups.

30 If desired, it is also possible at the same time to use isocyanates having only one isocyanate group, generally in a proporl~ion of not more than 10 mol~ based on the overall molar amount of monomers. The rnonoisocyanates will normally carry furthe:r functional group-;, such as olefinic or carbonyl groups, 35 and wiLl serve to introduce into the polyurethane functional groups which make it possible for the polyurethane to undergo dispersion, crosslinking or further, polymer-analogous reactions.
Monome:rs suitable for th:is purpose are those such as isopropenyl-a,~-dimethylbenzyl isocyanate (TMI).

To prepare polyurethanes with a certain degree of branching or crosslinking, it is poss:ible, for example, to use trifunctional and tetrafunctional isocyanates, which are obtained, for example, by brimging together difunctional isocyanates in a reaction in 45 which some of their isocyanate groups are derivatized to form allophanate, biuret or isocyanurate groups. Examples of ~ ' 0050/46229 commerc:ial compounds are the isocyanurate or the biuret of hexamet:hylene diisocyanat:e.

Examples of other suitable polyisocyanates, of higher 5 functionality, are polyisocyanates which contain urethane groups and are based on 2,4- ancl/or 2,6-diisocyanatotoluene, isophorone diisocyanate or tetramethylene diisocyanate on the one hand and on low molecular mass polyhydroxy compounds, such as trimethylolpropane, on the other.

~or good film formation and elasticity, polyols Ib) of ideal suitab.ility are high molecular mass polyols, preferably diols (bl), ,having a molecular weight of about 500-5000 g/mol, 15 preferably about 1000-3000 g/mol.

The polyols (bl) are especially polyesterpolyols as known, for example, from Ull ~nnfi Encyklopadie der technischen Chemie, 4th Edition, Volume 19, pp. l52-65, preferably those obtained by 20 reacting dihydric alcoho.ls with dibasic carboxylic acids. Instead of the free polycarboxyl.ic acids it is also possible to employ their anhydrides or este:rs with lower alcohols, or mixtures thereof, in order to pre]pare the polyesterpolyols. The polycarboxylic acids may be aliphatic, cycloaliphatic, 25 araliphatic, aromatic or heterocyclic and may be unsaturated and/or substituted, for ~example by halogens. Examples of such compounds are suberic, azelaic, phthalic and isophthalic acids, phthalic, tetrahydrophthalic, hexahydrophthalic, tetrachlorophthalic, en~ sthylenetetrahydrophthalic and glutaric 30 anhydrides, maleic acid, maleic anhydride, fumaric acid and dimeric fatty acids. Preferred dicarboxylic acids are those of the formula HOOC-(CH2)y~COOH in which y is 1-20, preferably an even n.umber from 2 to 20, examples being succinic, adipic, dodeca.nedicarboxylic and sebacic acids.

Exampl.es of polyhydric alcohols are ethylene glycol, propane-1,2-diol, propane-1,3-diol, butane-1,3-diol, butene-1,4-diol, butyne-1,4-diol, pentane-1,5-diol, neopen,tylglycol, bis(hydroxymethyl)cyclohexanes such as 40 1,4-bi.s(hydroxymethyl)cyclohexane, 2-methylpropane-1,3-diol, methyl.pentanediols, and also diethylene, triethylene, tetraethylene, polyethylene, dipropylene, polypropylene, dibutylene and polybutylene glycols. Preference is given to neopentylglycol and to a.lcohols of the formula HO-(CH2)X-OH in 45 which x is 1-20, prefera.bly an even number from 2 to 20, examples being e!thylene glycol, butane-1,4-diol, hexane-1,6-diol, octane-1,8-diol and dodecane-1,12-diol.

Also suitable are polycarbonatediols as can be obtained, for 5 example, by reacting phoEgene with an excess of the low molecular mass a]cohols mentioned as synthesis components for the polyest:erpolyols.

10 Suitability extends to lactone-based polyesterdiols, which are homo- or copolymers of lactones, preferably hydroxyl-terminated adduct-; of lactones with suitable difunctional starter molecules.
SuitabLe lactones are preferably those derived from compounds of the formula H0-(CH2)z-COOH in which z is 1-20, examples being 15 ~-caprc,lactone, ~-propiolactone, y-butyrolactone andtor methyl--~-caprolactone and mixtures thereof. Examples of suitable starter components are the low molecular mass diols mentioned as synthe~3is components for the polyesterpolyols. The corresponding polymers of E-caprolactone are particularly preferred. Lower 20 polyeslterdiols or polyetherdiols can also be used a~ starters for preparing the lactone po:Lymers. Instead of the polymers of lactones it is also poss:ible to employ the corresponding, chemically equivalent po:Lycondensation products of the hydroxycarboxylic acids corresponding to the lactones.

The polyesterols may also be prepared from minor amounts of monofunctional and/or poLyfunctional monomers.

Further suitable monomer~3 (bl) are polyetherdiols. They are 30 obtainable, in particula:r, by polymerizing ethylene oxide, propyl,ene oxide, butylene oxide, tetrahydrofuran, styrene oxide or epichlorohydrin with itself, for example, in the presence of BF3, or by subjecting these compounds, alone or in a mixture or in succession, to addition reaction with starting components 35 containing reactive hydrogens, such as alcohols or amines, for example water, ethylene glycol, propane-1,2-diol, propane-1,3-diol, 1,2-bis(4-hydroxydiphenyl)propane or aniline.
Particular preference is given to polytetrahydrofuran with a molecular weight ranging from 240 to 5000 and especially from 500 40 to 4500.

Likewise suitable are polyhydroxy olefins, preferably those having 2 terminal hydroxyls, for example a-w-dihydroxypolybutadiene [sic], a-w-dihydroxypolymethacrylic 45 [sic] esters or a-w-dihydroxypolyacrylic [sic] esters, as monomers (bl). Such compounds are known, for example, from EP-A-0 622 378.

~ CA 02230827 1998-03-19 ~ 0050/46229 Other ~;uitable polyols are polyacetals, polysiloxanes and alkyd resins.

The po:lyols may also be employed as mixtures in any desired 5 proportions.

The ha:rdness and modulus of elasticity of the polyurethanes can be increased if the polyols (b) employed include not only polyols lO (bl) but also low molecu:Lar mass diols (b2) having a molecular weight of about 62-500 g,~mol, preferably 62-200 g~mol.

The compounds used as monomers (b2) are in particular the synthesis components of the short-chain alkanediols mentioned for 15 the preparation of polyesterpolyols, with preference being given to neopentylglycol and to the unbranched diols having 2, 4, 6, 8, 10 or 12 carbons.

Based on the overall amount of polyols (b) the proportion of 20 polyols ~bl) is preferably 10-100 mol% and that of monomers (b2) is preferably 0-90 mol%. The ratio of the polyols (bl) to the monomers (b2) is preferably from 0.2:1 to 5:1, particularly preferably from 0.5:1 to 2:1.

25 Compounds particularly suitable as components (c) are those of the formula (I), which are obtainable by subjecting a diketene of the formula ~IV) O

l l IV
R1 ~ ~ ~ R3 to an addition reaction with an alkanolamine of the formula (V) H - N V

0050/4~229 In the diketenes of the formula ~IV) and the amines of the formula, (V), Rl, R2, R3 and R4 and R5, R6 and R7, respectively, are as defi.ned for the formula (I).

5 It is preferred to employ a diketene in which Rl, R2 and R3 are hydrogen or in which one of Rl and R2 is hydrogen and the other is, li~;e R3, linear, saturated and unsubstituted hexadecyl.

lO Partic-llarly preferred amines are monoaminopolyols with two aliphat:ically attached hydroxyls, such as l-amino-2,3-propanediol, 2-amino-l,3-propanediol, 2-amino-2-methyl-1,3-propanediol, 2-amino-2-ethyl-1,3-propclnediol, 15 2-amino-l-phenyl-l,3-propanediol, diethanolamine, diisopropanolamine, 3-(2--hydroxyethylamino)propanol and N-(3-hydroxypropyl)-3-hydroxy-2,2-dimethyl-l-aminopropane.

Also suitable are monoaminopolyols having more than 2 20 alipha1:ically attached hydroxyl~, such as tris(hydroxymethyl)methylamine) [sic], 2-[tri:i(hydroxymethyl)me1:hylamino]ethanesulfonic acid, 3-[tris(hydroxymethyl)methylamino]propanesulfonic acid, N-[tri:3[hydroxymethyl)methyl]glycine [sicl, 25 tris(3-hydroxypropyl)methylamine, glucamine and N-(2-hydroxyethyl)glucam:ine, or diaminodiols, such as N,N'-b:is~2-hydroxyethyl)ethylenediamine, reaction products of a diprimary polyetherdiamine and, per mole of polyetherdiamine, 2 mol of ethylene, propy:Lene and/or butylene oxide, the 30 condit:ions for reaction of the polyetherdiamine with the alkylene oxide being selected so ilS to give with high selectivity the N,N'-b.is~hydrooxyalkylam:ine) [sicl derivative havin~ two secondi~ry aminos. Examples of the polyetherdiamines are 4,7-dioxadecane-l,lO-diamine, 4,ll-dioxatetradecane-l,l4-~; ~ m ine, 35 a-~2-~ ;n~ ~thylethyl)-~-~2-aminomethylethoxy)polyloxy(methyl-l,2-eth~neAiyl)] having an MW of 200-3000, and ~-(3-aminopropyl)-~-~3-aminopropoxy)poly[oxy~l,4-butanediyl)]
having an MW of 300-3000.

40 Use may likewise be made of monoaminopolyols having only one aliphatically attached hydroxyl, such as ethanolamine, N-methylethanolamine, N-~ethylethanolamine, N-butylethanolamine, N-cyclohexylethanolamine, N-tert-butylethanolamine, leucinol, isoleu,-inol, valinol, prolinol, hydroxyethylaniline, 45 2-(hyd:roxymethyl)-piperildine, 3-~hydroxymethyl)piperidine, 2-(2-hydroxyethyl)piperi,dine, 2-amino-2-phenylethanol, 2-amino-l-phenylethanol, ephedrine, p-hydroxyephedrine, norephedrine, adrenaline, noradrenaline, serine, isoserine, phenylserine, 1,2-dipheny:1-2-aminoethanol, 3-amino-1-propanol, 2-amino-1-propanol, 2-amino-2-methyl-1-propanol, isopropanolamine, N-ethyl.isopropanolamine, 5 2-amino-3-phenylpropanol, 4-amino-1-butanol, 2-amino-1-butanol, 2-aminoisobutanol, neopentanolamine, 2-amino-1-pentanol, 5-amino-1-pentanol, 2-ethy1-2-butyl-5-aminopentanol, 6-amino-1-hexanol, 2-amino-1-hexanol, 2-(2-aminoethoxy)ethanol, 3-(aminomethyl)-3,5,5-trimethylcyclohexanol, 10 2-aminobenzylalcohol, 3-aminobenzylalcohol, 2-amino-5-methylbenzylalcohol, 2-amino-3-methylbenzylalcohol, 3-amino-2-methylbenzylalcohol, 3-amino-4-methylbenzylalcohol, 3-A i n - ?thylbenzylalcohol, 1-aminoethyl-4-hydroxybenzylalcohol, 2-(4-am,inophenyl)ethanol, 2-(2-aminophenyl)ethanol, 15 1-(3-am~inophenyl)ethanol, serine [sicl, homoserine, threonine, ethanolamineacetic acid, 4-amino-3-hydroxybutyric acid, N-(2-hydroxyethyl)glycinenitrile, 4-(2-hydroxyethyl)piperazine and l-amino-4-(2-hydroxyethyl)piperazine, 2-hydrazinoethanol or diaminc,monools, such as N-(2-aminoethyl)ethanolamine, 20 1-[2-(2-hydroxyethoxy)ethyl]piperazine, and 1,3-dia~ino-2-propanol.

Preference is given to the use of compounds of the formula (I) prepared from monoamino monoalcohols or polyamino monoalcohols, 25 based on the amounts of all monomers (c), in amounts of not more than SCI mol%, particularly preferably not more than 20 mol%.

Those monomers (c) comprising mono- or polyamino monoalcohols, 30 employed in minor amounts, serve, for example, to control the viscosi.ty during polyurethane synthesis.

Preferred adducts of the formula I are those of the diketene in which ~1, R2 and R3 are hydrogen with the compounds (Ia).
Compounds of the formula (I) can, for example, be prepared-in the fashion described for the acetoacetamide derivatives in DE 11 4L2 859 or GB 715,896.

g~ Also suitable as components (c) are condensation products comprising structural elements derived from compounds of the formula (I) (condensates I), such as carbonyl-containing polyest:erpolyols having 2L molecular weight of 300-5000, and which are obt:ainable, for examE~le, by polycondensation of x) compounds of the formula I in which the sum of the hydroxyls which are attached to aliphatic carbons and are carried by su~bstituents Rs and R6 and, if appropriate, R7 together is 2 (compounds Ia) and y) if desired, dioils other than the compounds (Ia), having a molecular weight of 62-500 g/mol (diols y) 10 Z) with dicarboxylic acids, the moLar ratio of the sum of the compounds (Ia) and the diols (y) to the dicarboxylic acids being from 2:1 to 1.05:1.

15 Preferred diols (y) and preferred dicarboxylic acids (z) are those compoundfi also used to synthesize the polyesterdiols (bl).

To prepare the condensates (I) it is likewise possible, preferably in minor amounts, to employ monofunctional and~or more 20 than difunctional alcohoLs or carboxylic acids. The preparation of such condensates (I) is known, for example, from US 5,321,118.

The monomers (d), which are different from components (b) and 25 diols ~c), serve generally for crosslinking or chain extension.
In general they are tri- or higher-functional nonaromatic alcohols, amines with 2 or more primary and/or secondary aminos, and compounds which carry not only one or more alcoholic hydroxyls but also one or more primary and/or secondary aminos.

Examples of trihydric and higher-functional alcohols which can be used to establish a certain degree of crosslinking or branching are trimethylolpropane, glycerol and sucrose.

35 Others which come into consideration are monoalcohols which as well as the hydroxyl carry a further isocyanate-reactive group, such as one or more primary and/or secondary aminos; one example is monoethanolamine.

40 Polyamines, with 2 or more primary and/or secondary aminos, are used in particular when chain extension or crosslinking is to take place in the presence of water, since amines generally react faster with isocyanates than do alcohols or water. This is frequently necessary when the desire is for aqueous dispersions 45 of crosslinked polyurethanes or of polyurethanes of high molecular weight. In such cases a procedure is followed in which isocyanato-containing prepolymers are prepared, are dispersed rapidly in water and then crosslinked or chain-extended by adding compounds having two or more isocyanate-reactive amino groups.

Amines suitable for this purpose are generally polyfunctional and 5 from the molecular weight: range from 32 to 500 g/mol, preferably from 6() to 300 g/mol, ancl contain at least two primary, two secondary or one primary and one secondary amino group. Examples are diamines, such as diaminoethane, diaminopropanes, ~;A inohutane5~ diaminohexanes, piperazine, 10 2,5-dimethylpiperazine, amino-3-aminomethyl-3,5,5-trimethylcyclohexane (isophoronediamine, IPDA), 4,4'-d:iaminodicyclohexylMethane, 1,4-diaminocyclohexane, aminoelhylethanolamine, hydrazine or hydrazine hydrate, or triamines, such as diethylenetriamine or 15 1,8-diamino-4-aminomethyloctane.

The amines may also be employed in blocked form, for example in the fo:rm of the corresponding ketimines (see eg. CA-l 129 128), 20 ketazimes (cf. eg. US-A ~1,269,748) or amine salts (see US-A 4,292,226). In addition, oxazolidines as used, for example, in US-,~ 4,192,937 constitute masked polyamines, which for preparing the novel polyurethanes can be employed for chain extending the prepolymer<;. When such masked polyamines are used, 25 they are generally mixed with the prepolymers in the absence of water to form a mixture which is subsequently combined with the dispersion water or with part of the dispersion water, such that the ap~propriate polyamines are released by hydrolysis.

30 The polyurethanes preferably contain no polyamine or l-10 mol%, particularly preferably 4-8 mol%, based on the overall amount of compon,ents (b), (c) and (d), of a polyamine having at least 2 isocyanate-reactive amino groups, as monomers (d).

35 Furthermore, for chain termination, use may also be made, in minor amounts, ie. preferably in amounts of less than lO mol%, based ,on components (b) ,and (d), of monoalcohols. Their function is generally similar to that of the monoisocyanates, ie.
principally to functionalize the polyurethane with free-radically 40 polymerizable C=C double bonds.

Furthermore, for chain termination, use may also be made, in minor amounts, ie. preferably in amounts of less than 10 mol~, based on components (b) and (d), of monoalcohols. Their function 45 is generally similar to that of the monoisocyanates, ie.

principally to functionalize the polyurethane with free-radically polymerizable C=C double bonds lsic].

To give the polyurethanes dispersibility in water, they are 5 genera.lly composed not only of components (a) - (d) but also of monome:rs le), different from components (a) - (d), which carry at least one isocyanate group or at least one isocyanato-reactive group and, in addition, at least one hydrophilic group or a group which ,can be converted to hydrophilic groups. In the text below lO the te:rm "hydrophilic groups or potentially hydrophilic groups"
is abb.reviated to "(potentially) hydrophilic groups". The (potentially) hydrophilic groups react with isocyanates substantially more slowly than the functional groups of the monomers used to synthes.ize the polymer main chain.

The proportion of components having (potentially) hydrophilic groups among the total amount of components (a) - (e) is generally such that the molar amount of (potentially) hydrophilic 20 groups, based on the amount by weight of all monomers (a) to (e), is from 30 to 1000 mmol/kg, preferably from 50 to 500 mmol/kg and, with particular preference, from 80 to 400 mmol/kg.

The (potentially) hydrophilic groups may comprise nonionic or, 25 preferably, (potentially) ionic hydrophilic groups.

Suitable nonionic hydrophilic groups are, in particular, polyethylene glycol ethers comprising preferably 5-100, particularly preferably 10-80, ethylene oxide repeating units.
30 The content of polyethylene oxide units is generally from 0 to 10% by weight, preferably from 0 to 6% by weight, based on the amount by weight of all monomers (a) to (e).

Preferred monomers containing nonionic hydrophilic groups are the 35 reaction products of a polyethylene glycol and a diisocyanate ~ which carry a terminally etherified polyethylene glycol radical.
Diisocyanates of this kind and methods of preparing them are indicated in US 3,905,929 and 3,920,598.

Ionic hydrophilic groups are, in particular, anionic groups such as sulfonato, carboxylato and phosphato, in the form of their alkali. metal or ammonium salts, and also cationic groups, such as ammoni.um groups, especially protonated tertiary amino groups or 45 quaternary ammonium groups.

Potentially ionic hydroph.ilic groups are, in particular, those which by simple neutralization, hydrolysis or quaternization reactions can be converted into the abovementioned ionic hydrophilic groups, examples therefore being carboxyl, tertiary 5 amino or anhydride groups.

(Potentially) ionic monomers (e) are described at length, for example, in Ull ?nn~ Encyklopadie der technischen Chemie, 4th Edition, Volume 19, pp. 311-313 and DE-A-14 95 745.

Of particular significance in practice as ~potentially) cationic monomers (e) are especially monomers containing tertiary amino groups, examples being tris(hydroxyalkyl)amines, 15 N,N'-bis(hydroxyalkyl)alkylamines, N-hydroxyalkyldialkylamines, tris(amlinoalkyl)amines, N,N~-bis(aminoalkyl)alkylamines and N-aminoalkyldialkylamines, in which each alkyl and alkanediyl indepen.dently is a C2-C6 moiety. Others which come into consideration are polyethers which have tertiary nitrogens and 20 prefera.bly two terminal hydroxyls, as can be obtained, for example, by alkoxylating amines which have two hydrogens attached to the amine nitrogen, for example methylamine, aniline or N,N'-di.methylhydrazine, in a manner known per se. Polyethers of this ki.nd generally have a molecular weight of 500-6000 g/mol.

These t.ertiary amines are converted into the ammonium salts either with acids, preferably strong mineral acids such as phosphoric, sulfuric or hydrohalic acids or strong organic acids, or by reaction with suitable quaternizing agents, such as 30 Cl-C6-alkyl halides, for example bromides or chlorides.

Suitable monomers containing (potentially) anionic groups are, customarily, aliphatic, cycloaliphatic, araliphatic or aromatic carboxylic and sulfonic acids which carry at least one alcoholic 35 hydroxyl or at least one primary or secondary amino group.
Preference is given to dihydroxyalkylcarboxylic acids, especially of 3 to 10 carbons, as are described inter alia in US-A 3,412,054. Particula.r preference is given to compounds of the formula 0050/4~229 CA 02230827 1998-03-19 COOH
I

HO - Ra - C - Rb - OH

RC

10 in which Ra and Rb are each C1-C4-alkanediyl, and Rc i8 Cl-C4-alkyl, and especially to dimethylolpropionic acid ~DMPA).

Appropriate dihydroxysulfonic acids and dihydroxyphosphonic acids 15 such as 2,3-dihydroxypropanephosphonic acid are also suitable.

Suitab:ility extends to dihydroxy compounds having a molecular weight of 500-10,000 g/mol and at least 2 carboxylate groups, which are known from DE-A 39 11 827. They can be obtained by 20 reacting dihydroxy compounds with tetracarboxylic dianhydrides, such a3 pyromellitic dianhydride or cyclopentanetetracarboxylic dianhydride, in a molar ratio of 2:1 to 1.05:1 in a polyaddition reaction. Particularly suitable dihydroxy compounds are the monomers (b2) mentioned as chain extenders and also the polyols 25 (bl).

Suitable monomers (e) containing isocyanate-reactive amino groups are aminocarboxylic acids such as lysine, ~-alanine, the adducts of aliphatic diprimary diamines with a,~-unsaturated carboxylic 30 acids that are indicated in DE-A 20 34 479, such as N-(2-aminoethyl)-2-aminoethanecarboxylic acid, and also the corres]ponding N-aminoalkylaminoalkylcarboxylic acids where the alkanediyls are of 2 to 6 carbons.

35 Where monomers having potentially ionic groups are employed, they can be converted into the ionic form prior to, during or, preferably, after the isocyanate polyaddition, since the ionic monomers are frequently difficult to dissolve in the reaction mixture. With particular preference, the carboxylate groups are 40 in the form of their salts, with an alkali metal ion or ammonium ion as counterion.

In the field of polyurethane chemistry it i~ generally known how 45 the molecular weight of the polyurethanes can be adjusted by choosing the proportions of mutually reactive monomers and the arithmetic mean of the number of reactive functional groups per molecu.le.

Normally, components (a)~ (b), (c), (d) and (e) and their 5 respective molar quantities are chosen such that the ratio A:B
between A) th.e molar quantity of isocyanate groups and B) th,e sum of the molar quantities of hydroxyl and of functional groups able to react with isocyanates in an addition reaction is from 0.5:1 to 2:1, preferably from 0.8:1 to 1.5:1, 15 particularly preferably from 0.9:1 to 1.2:1 and, with very particular preference, as close as possible to 1:1.

In addition to components (a), (b), ~c), (d) and (e) use is made of monomers having only one reactive group, in general in amounts 20 up to 15 mol~, preferably up to 8 mol%, based on the overall amount of components (a) - (e).

The polyaddition reaction of components (a) - (e) is generally 25 carried out at from 20 to 180~C, preferably from 50 to 150~C, under atmospheric or autogenous pressure.

The reaction time necessary may extend from a few minutes to several hours. It is known in the field of polyurethane chemistry 30 how the reaction time can be influenced by a variety of parameters such as temperature, monomer concentration and monomer reactivity.

The reaction of the diisocyanates can be accelerated using the 35 customary catalysts, such as dibutyltin dilaurate, tin(II) octoat.e and diazabicyclo[2.2.2]octane.

Suitable polymerization apparatus comprises stirred vessels, especi.ally if solvents are used to provide for low viscosity and 40 good h,eat dissipation. For reaction in the absence of solvents, the usually high viscosities and usually short reaction times render the use of extrud.ers, especially self-cleaning multiscrew extrud~ers, particularly suitable.

The di.spersions are usua.lly prepared by one of the following techni.ques:

- ' 0050/46229 In accordance with the acetone technique, an anionic polyurethane is prepared from components (a) - (e) in a water-miscible solvent which boils below 100~C at atmospheric pressure. A sufficient amount of water is added to form a dispersion in which water is 5 the coherent phase.

The prepolymer mixing tec:hnique differs from the acetone technique in that the initial product prepared is not a fully reacted (potentially) anionic polyurethane but a prepolymer which 10 carries isocyanate groups. In this case components (a) - (d) are chosen so that the above--defined ratio A:B is more than from 1.0 to 3, preferably from 1.()5 to 1.5. The prepolymer is first dispersed in water and then either crosslinked by reacting the isocyanate groups with amines having more than 2 15 isocyanate-reactive amino groups or chain-extended using amines having 2 isocyanate-reaclive amino groups. Chain extension also takes place if no amine :is added. In this case, isocyanate groups are hydrolyzed to amino groups which react, extending the chain, with remaining isocyanate groups of the prepolymers.

In a particularly preferred variant of the acetone and of the prepolymer mixing technique, the prepolymer is prepared in 2 steps, in the first of wllich components ~c) and, if used, (b2) 25 and some of component (a~ are first reacted with one another until virtually all of the isocyanate groups of component (a) have b,een reacted. The progress of this reaction can be found by measuring the NCO value, ie. by detel ining the number of remainin~ NCO groups. In the subsequent step, the residual 30 compon,ents may be reacted with one another to form a prepolymer and, whether this is done or not, are added to the reaction mixtur,e formed from (a), (c) and, if used, (b2), and the reaction is continued.

35 Where a solvent was used in preparing the polyurethane, the majority of the solvent is usually removed from the dispersion by, for example, carrying out distillation under reduced pressure. The dispersion3 preferably have a solvent content of less than 10% by weight, and with particular preference are free 40 from solvents.

The dispersions generally have a solids content of from lO to 75%
by weight, preferably from 20 to 65% by weight, and a viscosity of from lO to 500 mPas (measured at 20~C at a shear rate of 45 250 s~

' 0050/46229 CA 02230827 1998-03-19 Normal:ly, the novel aqueous dispersions are virtually free from polyvalent metal ions.

Hydrophobic auxiliaries, which may be difficult to disperse 5 homogeneously in the finished dispersion, such as, for example, phenol condensation resins of aldehydes and phenol and/or phenol deriva-tives, or epoxy resins and other polymers mentioned, for example, in DE-A-39 03 5:38, 43 09 079 and 40 24 567, which are used im polyurethane dispersions as adhesion promoters, for 10 example, can be added to the polyurethane or to the prepolymer even before dispersion in accordance with the methods described in the two abovementioned documents. Examples of suitable hydrophobic auxiliaries are specified in DE-A-39 03 538, 40 24 567 and 43 09 079.

In a variant of the present invention, the novel polyurethane dispersions are modified with free-radically polymerizable monomers having a C=C do~ble bond but being devoid of isocyanate 20 groups or isocyanato-reactive groups (monomers f). These monomers comprise, in particular, the monomers normally employed in the preparation of emulsion polymerizations [sic].

Examples of suitable monomers (f) are Cl-C6-alkyl (meth)acrylates 25 and also lauryl acrylate and ~utanediol diacrylate, or carbonyl-cont~ining compounds, for example methyl vinyl ketone, (meth)acrolein, crotonaldehyde, diacetone(meth)acrylamide or diacetone (meth)acrylate.

30 Examples of other monomers are vinyl esters of C2-C20 carboxylic acids, such as vinyl laurate, stearate, acetate and propionate, vinyl-aromatic compounds of up to 20 carbons, such as styrene and vinyltoluene, ethylenically unsaturated nitriles, such as acrylonitrile and methacrylonitrile, ethylenically unsaturated 35 amides, such as acrylamide and methacrylamide, vinyl halides such as vinyl chloride, and vinylidene chloride, and C2-C~ aliphatic hydrocarbons with 1 or 2 C=C double bonds, such as butadiene and ethylene.

40 The monomer (f) can be added during the synthesis of the polyurethane (A), prior to its dispersion or to the aqueous dispersion containing the polyurethane (A), and can be free-radically polymerized by conventional methods, adding free-radical initiators to the mixture of polyurethane dispersion 45 and monomer (f). It can also be metered as a feed stream into an initiator-containing polyurethane dispersion.

If it is desired to graft the polymer formed from monomer (f) onto the polyurethane, it is advisable to employ monomers containing a free-radically polymerizable C=C double bond when synthesizing the polyurethane.

To crosslink the polyurethane (A), the aqueous dispersion normally has added to it a crosslinker (B) containing functional substituents which react in addition or condensation with the structu~ral units derived from compounds of the formula (I).
10 Example~s of such crosslinkers (B) are compounds having at least one alclehyde group or at least two functional substituents selected from the group consisting of primary amino, secondary amino, hydrazine group, hydrazide group, aminooxy group, isocyanate group, N-methylol group and blocked isocyanate group.

Examples of suitable polyamines are nonpolymeric amines, such as ethylenediamine, diethylenetriamine, triethylenetetramine, propylenediamine, butylenediamine, 1,6-hexanediamine, 20 1,12-dodecanediamine, cyclohexylenediamine, piperazine, 2-methylpiperazine, isophoronediamine, phenylenediamine, tolylenediamine, xylylenediamine, 4,4'-diaminodiphenylmethane, menthanediamine and m-xylenediamine. The reactive amino compound can also be a polymer, for example an amino-containing acrylic, 25 polyest:er or polyurethaneiresin, an amino-containing polypropylene oxide (Jeffamines), or a polyethyleneimine.

These amines can also be employed in blocked form, ie. in the form oi their aldimines or ketimines. These blocked amines are 30 known and are described, for example, by K.J. Kim and R.C. Williams in "Proceedings of the annual Water-Borne and Higher Solids Symposium, New Orleans, 57, (1993)" and by B. Vogt:-Birnbrich in ~Prc,ceedings of the 21st International Conference in Organic Coatings, Athens, 55, (1995)" and in 35 EP-A-5'i2 469 and EP-A-584 818. Preference is given to the use of amines blocked with aromatic aldehydes such as benzaldehyde.

Examples of suitable polyhydrazides are dicarboxylic acid dihydrazides, as are described, for example, in EP-A-442 652 on 40 page 1], line 52 to page 12, line 1. These are derived preferably from dicarboxylic acid~ which also form the basis for the polyest:erdiols which can be employed as component (bl).
Furthermore, the corresponding polyhydrazone derivatives can also be usecl, for example those derived from acetone or butanone.

~ ' 0050~46229 Further suitable polyhydrazides of heightened water-solubility are described, for example, in EP-A-629 657.

Furthe:r suitable crosslinkers (B) are polyisocyanates which have 5 a crosslinking effect through transimination. Such compounds are described, for example, in DE-A-41 21 946.

Crosslinkers containing aminooxy groups, which may also be used 10 in the form of their salts, are known, for example, from EP-A-516 074 and from DE--A-42 19 384.

Another crosslinking option is to add mono- or polyfunctional aldehydes, which may, if desired, also be protected, to the novel 15 dispersion.

Examples of suitable monoaldehydes are compounds of the formula X-R9-C]~O where R9 is Cl-C6-alkanediyl and X is hydrogen or hydroxycarbonyl. Preferred aldehydes are formaldehyde, 20 acetaldehyde and benzaldehyde.

Suitable polyfunctional aldehydes are low molecular mass compounds, especially aliphatic aldehydes of the formula OCH-(CH2)n-CHO where n is an integer from 0 to 8, preferably 0 to 25 4, such as glyoxal or glutaraldehyde.

Oligomers, polymers and copolymers of ethylenically unsaturated, free-radically polymerizable aldehydes can also be used as 30 crosslinking component. Suitable examples are acrolein, methacrolein, formylstyrene and hydroxymethylfurfuryl (meth)acrylate. If not sufficiently soluble, such crosslinking components can be dispersed in the aqueous phase of the dispersion and participate in film formation when the dispersion 35 is used as a binder. Preference is given to oligomeric or polymeric crosslinking components of this kind, with a weight-average molecular weight of 1000-500,000.

Derivatives with protected aldehyde groups are understood as 40 being those whose reactivity is comparable with that of the free aldehyde groups themselves. Suitable examples are acetals, mercapltals and mercaptols, dioxolanes and dithiolanes. Preference is given to acetal and dioxolane groups formed from the reaction of aldlehyde groups with C1-C4-alkanols or with C2-C3-alkanediols.

Examples of unsaturated monomers with protected aldehyde functions are diethoxypropyl acrylate and methacrylate, and acryloyl- or methacryloyloxypropyl-1,3-dioxolane.

5 Further suitable aldehyde derivatives are aldimine compounds which are obtained by reacting a substituted or unsubstituted aromat:ic or heteroaromatic aldehyde with a mono- or polyfunctional primary amine. Such compounds are part of general knowledge and are described, for example, in EP 552 469 A3 and in 10 US-A-5,451,653.

Crossl.inking may also take place by way of Michael acceptorR, suitab.1e compounds of thiR type being generally known and 15 descri~bed in DE-A-42 37 492.

Crosslinking by Michael addition is generally carried out in the presen,ce of a catalyst which is suitably a Lewis or Bronstedt base as described in DE-A-42 37 492.

The amounts of components (A) and (~) are preferably chosen such that the molar ratio of the carbonyl groups of structural units derived from compounds o~ the formula (I) to the functional substituents of compounds ~B) is from 0.1:1 to 10:1, preferably 25 from 1.5:1 to 0.5:1.

Further suitable crosslinkers ~B) are amino resins, for example melamine-formaldehyde condensation products as described in D.H. Solomon, The Chemistry of Organic Film polymers, p. 235 ff., 30 John Wiley & Sons, New York, 1967. These are preferably melamine-formaldehyde condensation resins having a molecular weight of preferably 250-1000, particularly preferably their partially or completely etherified derivatives. The degree of etherification is preferably at least 45% based on the maximum 35 possible. The melamine-formaldehyde condensation products are etherified with C1-C4 monoalcohols, for example with methanol, ethanol, propanol or preferably butanol, and/or with monoethers of diols having a total of 2 to 7 carbons.

However, the melamine-formaldehyde condensation products can also be replaced in part by other crosslinking amino resins, as are described, for example, in Methoden der organischen Chemie (Houben-Weyl), vol. 14/2, part 2, 4th edition, Georg Thieme 45 Verlag, Stuttgart, 1963, p. 319 ff.

' 0050/46229 Further crosslinking options arise with polyisocyanates.
Particularly suitable isocyanate compounds are the generally known and commercially available high-solids isocyanates, hydrophilicized and/or blocked isocyanates (cf. DE-A-42 16 536).

Suitable isocyanates are those listed as monomers ~a) which are used to synthesize the polyurethane. Among these, particular preference is given to the polyfunctional isocyanates having more than 2 isocyanate groups.

Examples of suitable blocking agents for the isocyanates are alcohols and oximes, for example acetone oxime or methyl ethyl ketoxime.

other possible crosslinkers (B) are polymeric resins which carry oxime-blocked isocyanate groups, as are described in DE-A-42 37 030, DE-A-33 45 448, W0 93/01245 and US-A-5,358,997.

20 The crosslinking of polyurethanes (A) present in the novel aqueous dispersion with a polyisocyanate takes place usually in the presence of a basic catalyst such as tertiary alkylamine.

With the exception of the nonblocked isocyanates and the 25 aldi~ines, the novel dispersions are generally mixed with the crosslinker at any desired moment prior to processing. It is likewise possible to add the crosslinker to the polyurethane (A) even prior to its dispersion in water.

The novel dispersions may additionally comprise further water-emulsifiable or water-dispersible resins, such as polymer, polyurethane, polyester, epoxy or alkyd resins, and commercially customary auxiliaries and additives, such as blowing agents, 35 antifoams, emulsifiers, thickeners, leveling agents and thixotropic agents, and colorants such as dyes and pigments.

Novel dispersions where the crosslinker (B) i8 a compound containing aldehyde-, primary or secondary amino-, hydrazine-, 40 aminoxy-, hydrazide- or ketoxime-blocked isocyanate groups or is an amino resin constitute systems referred to as one-component systems, since they can be processed within any desired period of time following their preparation.

45 Novel dispersions to which a compound with nonblocked isocyanate groups has been added as crosslinker (B) are referred to as two-component systems, since mixing is customarily carried out by the dispersion user owing to the limited period of time within which the corresponding mixture is to be processed (about 8 hours).

5 The coating compositions prepared in this way are generally applied to the substrate workpiece by the techniques customary in the paint industry, ie. for example by rolling, spraying, spreading, pouring and dipping.

Subsequent drying or curing of the coating material can be carried out either by cold curing (ie. at 0-80~C, preferably room temperature) or by stoving (ie. normally at 80-280~C).

15 Crosslinkers particularly suitable for cold curing are those containing aldehyde, aldimine, primary or secondary amino, hydrazine, aminoxy or hydrazide groups.

It is supposed that the polyaddition or polycondensation reaction 20 Isic] w~hich bring about crosslinking in these systems take place only wh.en a large proportion of the water has evaporated. The coating compositions therefore constitute a one-component system comprising binder and crosslinker.

25 Cold cu.ring can also be carried out in the presence of crossli.nkers (B) containing free isocyanate groups. In the case of this kind of processing, application of the novel dispersion to the workpiece should take place within a period of no more than ak,out 8 hours after the time of mixing with the crosslinker.

Cold cu.ring can likewise be carried out when the crosslinkers (B) used contain (hetero)aromatic aldimine groups. In this case, dependi.ng on composition, the shelf life of the novel dispersions 35 ranges from one hour to several weeks.

Where t.he coating is to be processed by stoving, particularly suitabl.e crosslinkers are the abovementioned amino resins, blockedl and unblocked polyisocyanates and Michael acceptors.
Even wh~en a crosslinker is absent, a certain degree of crossli.nking of the polyu.rethane does take place under stoving conditi.ons. This is especially the case when crosslinking takes place i.n the presence of the Lewis or Bronstedt bases described 45 in DE~ 42 37 492, such as tertiary amines, for example l~8-diazabicyclo[5.4.o]undec-7-ene ~DBU).

' 0050/46229 CA 02230827 1998-03-19 The novel coating compositions are particularly suitable for coating wood, metal, plastics, paper, leather and textiles, for producing moldings and printing inks, and as adhesives.

5 A feature of the novel dispersions is that even those comprising relatively little or no leveling agent can be processed to give high-quality coating finishes.

10 Furthe:rmore, the novel dispersions can be processed both as one-and as two-component syslems by the techniques of both cold curing and stoving. This is advantageous for processors who employ 2 or more of this total of 4 processing variants, since for different techniques it is necessary to stock only a small 15 number of polyurethane dispersions.

Moreover, aqueous dispersions comprising the polyurethane (A) are outstandingly suitable for the production of printing inks.

20 These ]printing inks are preferably composed as follows:

(I) 15 - 30% by weight of a binder consisting essentially of the polyurethane (A) and the crosslinker (B) (II) ? - 15% by weight of a pigment (III) 2 - 5% by weight of an alcohol suitable as solvent 30 (IV) 4.5 - 10% by weight of customary additives (V) 45 - 70% by weight of water.

35 As crosslinkers (B) use is preferably made of the polyhydrazides, described in more detail above, in the abovementioned proportions.

The customary additives are auxiliaries and adjuvants generally 40 employed in printing inks, ie. waxes, antifoams, dispersants, wettin,~ agents and microcides [sic], for example.

Otherwise, the components (ii) [sic] to (v) [sic] employed in the printing inks are those generally employed in such inks, which are known, for example, from Ullmann~s Encyclopedia of Industrial ~ OOSO/46229 Chemistry, 5th edition, Volume A22; 1993 VCH Publishers, Inc.;
pp. 14:3-155.

These printing inks are particularly suitable for printing 5 polymer filma, such as polyethylene or polypropylene films, having a surface tension of from 30 to 50, preferably from 35 to 40, particularly preferably from 37 to 39 (in mN/m, measured with water at 23~C). Printing can be done by the customary techniques (cf. loc. cit. pp. 145 and 146).

The polymer films with the abovementioned surface tensions are commercially available films which have been corona treated.

15 In combination with the recl ?n~ed substrates, these printing inks exhibit favorable wetting properties. The printed films are resistant to customary mechanical stresses and solvents.

Abbreviations and trade names:

ADDH: Adipic dihydrazide Basonat~ PLR 8878: Water-emulsifiable isocyanate crosslinker from BASF
Basophob~ WE: Polyethylene wax dispersion from BASF

Basoplast~ 20 conc.: Diketene of stearic acid from BASF

BD-1,4: 1,4-Butanediol from BASF

BHAA: Adduct of 1 mol of diethanolamine and 1 mol of diketene DAAM: Diacetoneacrylamide DBU: 1,8-Diazabicyclo[5.4.0]undec-7-ene DETA: N-(2-Aminoethyl)-1,2-ethanediamine from BASF

DMEA: 2-Dimethylaminoethanol from BASF

DMPA: Dimethylolpropionic acid from Angu~ Chemie SC: Solids content in % by weight, measured after distillation IPDI: Vestanat IPDI from Huls/Isophorone diisocyanate Luhydr~n(19 A 848 S: Aqueous, autocrosslinking polymer dispersion from BASF

10 MEK: Methyl ethyl ketone MW: Molecular weight Neutral.l: Neutralizing agent for the ionic groups of polyurethane Neutra.1.2: As Neutral.l 20 NMP: N-Methylpyrrolidone NCD: Theoretical crosslinking density from the reaction of ADDH with incorporated BHAA ~in mmol/kg solids) 25 PD-1,3: 1,3-Propanediol Pluriol~ P 600: Polypropylene glycol from BASF

30 P-THF 2000: Polytetrahydrofuran 2000 from BASF

PUD: Polyurethane dispersion TEA: Triethylamine TMP: Trimethylolpropane VCD: Theoretical crosslinking density from the reaction of DETA with isocyanate groups (in mmol/kg solids) Wacobl.au~ 9A 918 018: Blue pigment paste from BASF ~+E.

~ 0050/46229 Examples Synthesis examples for compounds of the formula I
s Compound Ia 168.14 g of diketene (2 mol ) were added over the course of one hour at 25~C to an initial charge of 231.3 g (2.22 mol) of 10 diethanolamine, 1000 ml of tetrahydrofuran and 25 g of pyridine.
The excess diethanolamine and the pyridine were separated off by the ad~dition of ion exchanger (Lewatit) [sic] lOOGl, strongly acidic) and filtration. Following the addition of 2.7 g of triphenylphosphine to the degassed clear solution, the solvent 15 was removed on a rotary evaporator. 341.09 g of a pale yellow liquid (90.14% of theory) were isolated. The analytical data ( 13C-and 1H-NMR) indicate a purity of more than 95%. No starting compounds were detected in the product, but triphenylphosphine oxide is present.

Compound Ib 599.4 g (7.129 mol) of diketene were added over the course of 90 minutes at 25~C to an initial charge of 749.5 g (7.129 mol) of 25 diethanolamine and 1250 ml of tetrahydrofuran. The tetrahydrofuran was subsequently removed by distillation. A
viscous, pale yellow oil was isolated, which weighed 1354.4 g (theory 1348.9 g). The 13C- and 1H-NMR spectra confirm the structure of the product and indicate a purity of at least 95%.
30 No starting material was detected.

Compound Ic 35 Using the procedure described for compound Ib, 261 g (3.105 mol) of diketene were reacted with 326.4 g (3.104 mol) of diethano~ ine in 1000 ml of acetone; however, the reaction was carried out at 15~C and the diketene was added over the course of 15 minutes. After removal of the acetone, 596.9 g (theory 40 587.4 g) of a pale yellow-orange oil of low viscosity were isolated. The NMR spectra confirmed the structure of the product.
No starting material was detected.

Compound Id 565.4 g (6.726 mol) of diketene were added over the course of 2 hours at 15~C to an initial charge of 707.2 g ~6.726 mol) of 5 diethanola,mine and 848.4 g of methyl ethyl ketone. Subsequently, the solution was warmed to 40~C, 996.79 g (4.484 mol) of isophorone diisocyanate and 0.5 ml of dibutyltin dilaurate, as a 50% strength solution in xylene, were added, and the mixture was reacted at B5~C for 4 hours. The decrease in the isocyanate lO content was monitored by infrared spectroscopy (isocyanate signal at about 2270 cm~

Compound Ie Using the procedure described for compound Ib, 1614 g (19.2 mol) of diketene were reacted with 2018.6 g (19.2 mol) of diethanolamine in 2422 g of THF. In this case, the initial charge of TH~ and diethanolamine was cooled to 0~C and the addition of 20 diketene was made over about 2 h 30 min. Subsequently, the majori.ty of the solvent was removed by distillation under reduced pressure. The desired product, which still contained solvent residu.es, was isolated in the form of a pale yellow oil with a viscosity of 2400 mPa.s.
Synthesis Examples for polyurethane dispersions with carbonyl groups Compou.nd II

In a first stage, Pluriol P 600 was aminated: 150 ml/h of Pluriol P 600 were reacted continuously with 450 ml/h of ammonia in a 1.2 1 tubular reactor containing 500 ml of catalyst consisting of 35 50% Ni.O, 20% Cuo and 30% ZrO2. The reaction t~ ~rature in the reactc,r was 20~-215~C, the pressure was 200 bar and the amount of hydrogen was 50 l/h. The highly volatile constituents (water, ammoni.a) were distilled off at 1-3 mbar at a liquid-phase temperatùre of up to 100~C. The product is characterized by the 40 following parameters: total amine number: 174.1 mg of KOH/G
[sic]; tertiary amine number: 1.3 mg of KOH/G [sic]; secondary amine number: 6.3 mg of KOH/g; hydroxyl number: 30.2 mg of KOH/g, and wa,ter content 0.06% by weight.

45 In a Piecond stage, 2040 g of the above polyetheramine were charged to a 10 1 stirred vessel. The contents of the reactor were rendered inert by multiple evacuation and flushing with nitrogen. Then 500 g of propylene oxide were metered in at 105~C.
Following an after-reaction phase (to constant pressure), the vessel was evacuated for about 20 minutes in order to remove any readily volatile constituents. There was no need for further 5 working up. The resulting polyetheraminopolyol had the following charac1eristics: hydroxyl number: 291 mg of KOH/g; amine number:
147 mg of KOH/g; tertiary amine number: 36.3 mg of KOH/g;
secondary amine number: 102.9 mg of KOH/g; water content 0.12% by weight;; density 1000 g/cm3; pH 11.4, and viscosity 326 mPa.s.

In the last stage, 2640 g of the propoxylated polyetheramine and 300 g of tetrahydrofuran were combined and cooled, and 523.7 g (6.23 mol) of diketene were added with vigorous stirring over the course of 4 hours at 0-15~C. After the end of this addition, the 15 product was stirred at room t~ erature for 1 h and then the solven1t was removed under reduced pressure to give a pale orange oil wh:ich still contained solvent residues.

20 Compound III
105.14 g (1 mol) of diethanolamine were added to an initial charge at 40~C of 512 g (1 mol) of Basoplast 20 conc. and 500 g of toluene. At the end of the addition, the toluene was removed by 25 distilLation at 90-95~C, to give a pale brownish solid. IR
analysis confirmed the disappearance of the diketene structure.

Dispersion 1 30 110.4 g of isophorone diisocyanate (0.497 mol) and 0.07 g of dibutyLtin dilaurate as a 50% strength solution in xylene were added to an initial charge of 133.3 g of polytetrahydrofuran (MW
2000; 0.067 mol), 13,9 g (0.073 mol) of the compound Ia, 10.7 g of dimethylolpropionic acid (0.08 mol), 21 g of 1,4-butanediol 35 (0.23 mol) and 43.3 g of methyl ethyl ketone, and the mixture was reacted at 90~C for 2.5 hours. The resulting prepolymer was then diluted with 200 g of acetone and neutralized with 6.5 g of triethylamine (0.063 mol~. Before neutralization the isocyanate contenlt was 0.92 g/100 g (theoretically 0.68%). By adding 500 g 40 of fully deionized water and a solution of 3 g of diethy:Lenetriamine (0.029 mol) in 16.7 g of water followed by removaL of the acetone, an opalescent dispersion with a solids content of 37.5% and a p~I of 7.8 was obtained. The theoretical conten1t of keto groups is 245, and the theoretical salt content 45 is 214 mmol~kg solids.

' 0050/46229 Dispersion la: Polyurethane dispersion with carbonyl groups and adipic dihydrazide as crosslinker 0.82 g of adipic dihydrazide was added to 100 g of dispersion 1 5 (molar ratio of hydrazide to carbonyl groups of 1:1).

Dispersion lb: Polyurethane dispersion with carbonyl groups and polyet:hyleneimine as crosslinker 0.44 g of polyethyleneimine Polymin~ G10 was added as a 20%
strength aqueous solution to 100 g of dispersion 1 (ratio of amino to keto groups of about 1:1).

15 Dispersion 2: As dispersion 1 with direct addition of adipic acid dihydrazide Following the preparation procedure of dispersion 1, the dispersion was prepared from 400 g of polytetrahydrofuran 2000, 20 41.8 g of the compound Ia, 32.19 g of dimethylolpropionic acid, 63.08 g 1,4-butanediol, 331.23 g of isophorone diisocyanate, 19.43 g of triethylamine and 8.94 g of diethylenetriamine.
24.38 g of adipic dihydrazide (78.5% pure) were added prior to the distillative removal of the acetone. An opalescent dispersion 25 with a solids content of 36.6 and a pH of 7.8 was obtained.

Dispersion 3: As dispersion 2 with addition of adipic dihydrazide after distillation Dispersion 3 was prepared as for dispersion 2 but using compound Ib instead of compound Ia and adding the adipic dihydrazide prior to the distillative removal of the acetone.

35 An opalescent dispersion with a solids content of 36.4% and a pH
of 7.~ was produced.

Dispersion 4: polyurethane dispersion with carbonyl groups 317.8'l g of isophorone diisocyanate (1.43 mol) and 0.2 g of dibutyltin dilaurate as a 50% strength solution in xylene were added at 59~C to an initial charge of 400 g of polytetrahyrofuran (0.2 mol), 81.7 g of the compound Ia (0.43 mol), 32.19 g of 45 dimethylpropionic acid (0.24 mol), 38.75 g of 1,4-butanediol (0.43 mol) and 130 g of methyl ethyl ketone. The mixture wa~
reacted at 92~C for 5 hours. It was then diluted with 600 g of acetone and neutralized with 19.43 g of triethylamine (0.19 mol).
The isocyanate content prior to neutralization was 0.87 g/100 g (theore.tically 0.68%). Addition of 1350 g of fully deionized water, 8.94 g of a solution of diethylenetrialnine (0.086 mol) in 5 50 g of water, subsequent removal of the acetone and addition, after t:he end of distillation, of 44.16 g of adipic dihydrazide (84.7% pure, 0.215 mol) gave an opalescent dispersion with a solids content of 40% and a pH of 8.1. The theoretical content of keto groups is 478, and the theoretical salt content is 10 214 mmol/kg solids. The molar ratio of hydrazide groups to keto groups is 1:1.

Dispersion 4a Dispersion 4a was prepared as for dispersion 4 but with no ADDH
being added. In addition, it was mixed with 0.5% by weight, based on solids, of DBU.

20 Dispersion 5: Polyurethane dispersion with carbonyl groups 517.96 g of isophorone diisocyanate (2.33 mol) and 0.2 g of dibutyLtin dilaurate as a 50% strength solution in xylene were added at 65~C to an initial charge of 400 g of polytetrahydrofuran 25 (0.2 mol), 10.2 g of the compound Ib (0.58 mol), 46.95 g of dimethylolpropionic acid (0.35 mol), 90.12 g of 1,4-but~neA;ol (1 mol~ and 250 g of methyl ethyl ketone. The mixture was reacted at 91~C for 6 hours. It was then diluted with 700 g of acetone and neutra:Lized with 28.33 g of triethylcunine (0.28 mol). The 30 isocyanate content prior to neutralization was 0.90 g/100 g (theoretically 0.79%). Addition of 1800 g of fully deionized water, 13.76 g of diethylenetriamine (0.13 mol) as a solution in 50 g o:E water, subsequent removal of the acetone and addition, following the end of distillation, of 59.57 g of adipic acid 35 dihydrazide (84.7% pure, 0.29 mol) gave an opalescent dispersion having a solids content of 41% and a pH of 7.8. The theoretical content of keto groups is 480, while the theoretical salt content is 232 mmolJkg solids.

40 Comparison Example 1 (V): Polyurethane dispersion without carbonyl groups Following the procedure for dispersion 1, 400 g of 45 polytetrahydrofuran (0.2 mol), 32.1 g of dimethylolpropionic acid (0.24 mol), 90.1 g of butanediol (1 mol) and 348.2 g of isophoxone diisocyanate (1.565 mol) were reacted with 0.2 g of dibutyltin dilaurate solution in 160 [lacuna] of methyl ethyl ketone. After dilution with 600 g of acetone, an isocyanate content of 0.8 g/100 g was measured (theoretically 0.64%). The product was neutralized with 19.4 g of triethylamine (0.192 mol), dispersed with 1500 g of fully deionized water and crosslinked 5 with 8.6 g of triethylenediamine (0.083 g 1 8iC]) dissolved in 50 g of water, to give a polyurethane dispersion having an opalescent appearance, solids content of 37.5% and a pH of 7.9.
The th,eoretical salt content is 214 mmol~kg solids.

10 Comparison Example 2 (V): Example 8 of EP-A-332 326 was repeated without addition of adipic dihydrazide Instead of NHP, methyl ethyl ketone and acetone were used as 15 solvents, since for comparison purposes the dispersion is to be solvent-free.

The reactive keto compound was first of all prepared from 21.75 g of diethanolamine ( a . 207 mol) and 35.05 g of diacetoneacrylamide 20 (0.207 mol) in 35.05 g of methyl ethyl ketone.

In the subsequent synthesis of the prepolymer, the product Capa 210 was used to replace Oxyflex S 1063-120, since no closer specification of the composition of this polyester was given.
25 Capa 210 is a polycaprolactone from Interox having a molecular weight of 1000 g/mol (example 910 g/mol). The prepolymer was prepared without catalyst from 400 g of Capa 210 (0.4 mol), the adduct solution (0.207 mol), 51.18 g of DMPA (0.389 mol) and 437.93 g of isophorone diisocyanate (1.97 mol) in 201 g of methyl 30 ethyl ketone and after 4!; minutes at 90~C and cooling to 35~C had an iso,-yanate content of 6.88 g/100 g (theoretically 6.83~).
Neutralization was carried out with 40 g of triethylamine (0.395 mol) and dispersion with 1480 g of fully deionized water, the prepolymer being chain-extended with 45.3 g of hydrazine 35 hydrate (0.906 mol) dissolved in 92 g of water. Distillation of the solvents gave a milky white, slightly opalescent dispersion with a solids content of 38.3% and a pH of 8.1. The theoretical content of salt groups is 377, while the theoretical content of keto groups is 201 mmol/kg solids.

The dispersion had a strong odor of its own and, in the course of distillation and subsequent treatment, showed an increased tenden,-y to foam.

Comparison Example 2a (V): Treatment of the dispersion from Comparison Example 2 (V) with adipic dihydrazide 0.67 g of adipic dihydrazide was added to 100 g of the dispersion from C~ -rison Example ~ (molar ratio of hydrazide groups to keto groups of 1:1).

5 C.I~Prison Example 3 (V): Preparation of a PUD from a diethanolamine/diacetoneacrylamide adduct 23.13 g of diethanolamine (0.22 mol) and 37.23 g of 10 diacetoneacrylamide (0.22 mol) were reacted under nitrogen at 85~C
for 7 h in 40 g of methyl ethyl ketone. This solution was used without: further treatment.

Following the procedure for preparing dispersion 1, a prepolymer 15 was prepared from 400 g of polytetrahydrofuran (0.2 mol), 60.36 g of the adduct of diethanolamine and diacetoneacrylamide (0.22 mol), 32.19 g of dimethylolpropionic acid (0.24 mol), 57.68 g of butanediol (0.64 mol) and 317.89 g of isophorone diisocyanate (1.43 mol) in 130 g of methyl ethyl ketone using 20 0.2 g of dibutyltin dilaurate solution. Following dilution with 600 g of acetone, the isocyanate content was 0.88 g/100 g (theoretically 0.68%). The product was subsequently neutralized with 1'3.43 g of triethylamine and dispersed by adding 1500 g of fully deionized water. For crosslinking, 8.94 g of 25 diethylenetriamine were added as well. Removal of the solvents left a white dispersion with many inhomogeneities. Some of the polyurethane settled out overnight. The theoretical content of keto groups is 245, while the theoretical salt content is 214 mmol/kg solids.

Comparison Example 4 (V): Preparation of a PUD from dihydroxyacetone Following the procedure for preparing dispersion 1, a prepolymer 35 was prepared from 400 g of polytetrahydrofuran ~0.2 mol), 19.82 g of dihydroxyacetone (0.22 mol), 32.19 g of dimethylolpropionic acid (().24 mol), 69.39 g of butanediol (0.77 mol) and 346.79 g of isophorone diisocyanate ~1.56 mol) in 130 g of methyl ethyl ketone using 0.2 g of dibutyltin dilaurate solution (reaction 40 time: 4 h). The prepolymer solution was brown in color. Following dilution with 600 g of ac:etone, the isocyanate content was 0.79 g~'100 g (theoretically 0.68%). The product was neutralized with 1'1.43 g of triethylamine (0.19 mol) and dispersed with 1500 g of fully deionized water. Subsecluently, 8.94 g of 45 diethylenetri~ine dissolved in 50 g of water were added. Removal of the solvents gave a yellowish white dispersion with a solids conten1: of 37.1~ and a pE~ of 8.1. The theoretical content of keto groups is 245, while the theoretical salt content is 214 mmol/kg solids. Application of the composition by knife coating to a glass plate in a dry-film thickness of about 50 ~m gave a yellowish film with an orange peel structure.

Comparison Example 5 (v):

An attempt was made to prepare, from an adduct of diethanolamine lO and diacetoneacrylamide, a dispersion with a theoretically calculated keto group content of 335 mmol/kg solids from the following components for prepolymer synthesis: a preadduct of 34.7 g of diethanolamine and 55.85 g of diacetoneacrylamide was reacted at 85~C for 7 h in 60 g of N-methylpyrrolidone. 400 g of a 15 polyesterdiol of adipic acid, isophthalic acid and 1,6-hexanediol having a MW of 2000 ~Lupraphen~ VP 9206 from BASF AG), 40.24 g of dimethylolpropionic acid, 57.68 g of 1,4-butanediol, 90 g of methyl ethyl ketone, 362.35 g of isophorone diisocyanate and 0.2 g of dibutyltin dilaurate solution were added. After 2 h at 20 91~C, the prepolymer gelled. For this reason the r. ~-ning components (600 g of acetone, 24.3 g of triethylamine, 1550 g of fully deionized water and 8.8 g of diethylenetriamine) were not added.

25 Comparison Example 6 (V): Preparation of a PUD from diacetone alcohol 400 g of polytetrahydrofuran (0.2 mol), 32.19 g of dimethylolpropionic acid (0.24 mol), 81.11 g of butanediol 30 (o.9 mol), 13.42 g of TMP and 393.47 g of isophorone diisocyanate (1.77 mol) in 160 g of acetone with 0.2 g of dibutyltin dilaurate solution were first of all reacted in a 4 1 pressure vessel under autogenous pressure at 86~C. Then 34.35 parts of diacetone alcohol (0.3 mol) were added and the reaction was continued at 118~C for 3 35 hours. Following dilution with 600 g of acetone the isocyanate value was 0.81 g/100 g (theoretically 0.64%). For neutralization, 19.43 g of triethylamine (0.192 mol) were added. The dispersion was formed by adding 1650 parts of fully deionized water, after which crosslinking was carried out with 8.94 g of 40 diethylenetriamine (0.09 mol) dissolved in 50 g of water. Removal of the acetone gave a slightly opalescent, milky white dispersion with a solids content of 37.4% and a pH of 7.9. The theoretical content of keto groups is 308, while the theoretical salt content is 197 mmol/kg solids. Application of the composition by knife 45 coating to a glass plate in a dry-film thickness of about 50 ~m without film-forming auxiliaries gave a film with numerous stress cracks directed from the side toward the center. Butylglycol of neutral pH was slowly applied dropwise; coagulum formed after only the first few drops.

The dispersions of Examples 6 to 10 and of Comparison Examples 5 7(V) to lO~V) were prepared using the monomers indicated in Table 1 and by the method indicated in Example 3.

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Dispersion 11 Dispersion 11 was prepared in the same way as dispersion 6 but 5 without adding ADDH.
Solids content: 39.6 ph [sic:~: 7.9 10 Dispersion lla Disper~ion lla was prepared by mixing dispersion 11 with 0.5% by weight, based on solid resin, of DBU.

15 Dispersion llb Dispersion llb was prepared by mixing 100 parts of dispersion 11 with 2 45 parts of adipic acid dihydrazide (molar ratio of hydrazide groups to carbonyl groups of 1:1).

Dispersion 12 Dispersion 12 was prepared like dispersion 11 25 Solids content: 40.8%
pH: 7.9.

Dispersion 12a 30 Dispersion 12a was prepared by mixing 100 parts of dispersion 12 with 2.52 parts of adipic acid dihydrazide (molar ratio of hydrazide groups to carbonyl groups of 1:1).

35 Dispersion 13 Using the procedure indicated in the case of Example 3, a disper~ion was prepared from the following componentR: 678.4 g of compound II, 53.65 g of DMPA, 87.42 g of 1,4-butanediol, 537.97 g 40 of IPDI, 40.48 g of TEA and 17.2 g of DETA. The product was an opalescent dispersion having a solids content of 23.9% and a pH
of 8.4. The theoretical content of keto groups is 952, while the theoretical salt content is 228 mmol/kg solids.

~ 0050/46229 Dispersion 13a To 100 parts of dispersion 13 there were added 1.96 parts of adipic acid dihydrazide (molar ratio of hydrazide groups to 5 carbonyl groups of 1:1).

Dispersion 14 Using the procedure indicated in the case of Example 3, a dispersion was prepared from the following components: 400 g of polytetrahydrofuran 2000, 368.33 g of compound III, 83.16 g of DMPA, 36 05 g of 1,4-butanediol, 455.72 g of IPDI, 50.19 g of TEA
and 17.2 g of DETA. The product was an opalescent dispersion 15 having a solids content of 24.9% and a pH of 8Ø The theoretical content of keto groups is 400, while the theoretical salt content is 352 mmol/kg solids.

A. Performance tests as coating materials The results of the tests of performance as coating materials are reproduced in Tables 2a, 2b, 2c, 3, 4 and 5.

B. Preparation and performance testing of printing inks The dispersions of Table 6 were mixed with the amounts stated therein of pigments and other auxiliaries, by stirring the following components into the dispersion in the following 30 sequence:

1. a solution of ammonia and water 2. a solution of Basophob and the re!~;ning water 3. isopropanol 4. p:igment paste After optional storage the printing inks were applied to Corona-treated polyethylene with a surface tension of 38 mN/m by knife coating, then subjected to forced drying at 90~C or at 60~C
for 2 minutes. The dry-film thickness was s6 ~m.
The results of the tests of performance for printing inks are given in Table 7.

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N g~ ~ ~ r1 r l a ~ 0050/46229 Table 2b Test results of the films prepared in accordance with e) Disper- Swelling THFAV THF Swelling AV ethanol ~ion ethanol (50%) (50%) 1 881 % 18.6 % 767 % 14.2 %
la 401 % 4.0 % 222 % 0.4 %
lb 610 % 6.7 % 166 % 1.3 %
l(V) dissolved / dissolved 2(V) highly / 952% 15.9%
swollen*
152a(V) highly / 1011% 20.0%
swollen*
4 488 % 6.0 % 196 % 1.9 %
295 % 0.0 % 179 % 0.0 %
*very tacky Table 2c Steam test f) 25DigpersionVisual - Nail Visual - 1 h* Nail immed.* hardness - hardness - 1 h immed.* *

1~ 2 3 2 2 l(V) 3 5 3 2 2(V) 5 5 5 2 2atV) 5 5 5 2 ~ 3 5 1 2 35 .; 3 5 2 ~i 4 5 4 3 6a 2 2 1 2 6b 4 5 2 2 l;!a 1 2 13a 2 4 * 0 = best score, 5 = worst score ~ ' 0050/46229 These results show that even without crosslinkers the novel carbonyl-containing dispersion has improved resistance properties. Moreover, the addition of crosslinker in the case of the comparison product does not improve the resistance.

Table 3 Test results of the surfaces prepared in accordance with b) 10Dispersion 112 lla llb Acetone testl) l number ] ( j ) 60~C 50 50 > 100 70~C 60 > 100 80~C 75 15 90~C > 100 Pendu:Lum hardne~sl) [number] (c) 60~C 126 123 70~C 126 131 124 20 80~C 124 128 135 90~C 114 122 137 Erichsen indentationl ) 25[mm] (i) 60~C > 10 > lO > 10 70~C > 10 > 10 > 10 80~C > 10 > 10 > 10 90~C > 10 > 10 > 10 30Crosshatchl) lscore*] (h) 60~C 1 0 - 1 1 70~C 1 0 - 1 l 80~C 0 - 1 0 - l 0 - 1 Abrasion [mg] (g) 23.9 / 23.6 25.8 / 24.5 26 / 24.7 * 0 = best score, 5 = worst score 0 l) Films drawn out on gradient oven panels; 2) flash rusting The results from Tab. 3 show that, using a catalytic amount of a basic catalyst, the results obtained are c. p~rable with those obtained with a stoichiometric amount of crosslinker. The 45 addition of both DBU ~dispersion lla) and ADDH (dispersion llb) prevents flash rusting.

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strength 2 49.2 2.0 5.0 5.0 38.8 25 ~l 45.0 2.0 5.0 5.0 43.0 25 li 46.3 2.0 5.0 5.0 41.7 25 7 47 2.0 5.0 5.0 41 25 ~3 46.5 2.0 5.0 5.0 41.5 25 ~3 q9.2 2.0 5.0 5.0 38.8 25 46.2 2.0 5.0 5.0 41.8 25 7 (v) 39.1 2.0 5.0 5.0 38.9 25 25 8 (V) 41.6 2.0 5.0 5.0 46.4 25 9 (V) 42.7 2.0 5.0 5.0 45.3 25 10 (V) 52.6 2.() 5.0 5.0 35.4 25 -~n ~ 8 8 8 8 8 8 8 r ~
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Test methods 5 a) Film formation on glass The dispersions without additives were knife-coated onto glass plates in a dry-film thickness of about 50 ~m and were dried under standard conditions. After drying, the films were assessed visually. If defects were present in the film (inhomogeneities~ stress cracks, clouding, orange peel structure, craters, etc.) then the amount of butylglycol added to the dispersion~ wa~ just that which gave a film surface which after drying was clear, glossy and free from defects. The amount of butylglycol required is indicated as the solvent de an~ in % by weight.

b) Film formation on panels The dispersions were drawn using a film-drawing frame onto standard metal panels or onto gradient oven panels with a wet-film thickness of generally 150-200 ~m, dried at room temperature for 10 minutes, and then stoved.

c) The surface hardness (Pd hardness) was determined in accordance with DIN 53157 using a Ronig apparatu~. Table 1 indicates the number of strokes. The measurements were made at various times, indicated in Table 2a, following the application of the dispersions by knife coating.
d) Film thickness: determined in accordance with DIN 50 982 e) Swelling experiments So as to obtain comparable results, 5% by weight of butylglycol was added to all of the dispersions in order to improve film formation. ~ilms about 2 mm thick were cast.
After 10 days, film pieces were subjected to swelling in tetrahydrofuran (THF) or 50% strength ethanol for 24 h. After redrying, the leaching lo~s (AV) and swelling value were determined.

CA 02230827 l998-03-l9 f) Steam test The steam test was carried out in accordance with DIN 68860B
on two-coat systems on wood. Visual assessment and testing of the nail hardness were carried out immediately (imm.) and again after one hour.

g) Abrasion testing:

50 g of dispersion with a determined quantity of butylglycol added were stirred for 5 to 10 min using a Dispermat, left to stand for 1 day, and applied with a 200 ~m wire doctor to Abraser glass plates. After conditioning for 1 day at room temperature, for 16 hours at 60~C and for at least 48 hours in a controlled-climate chamber, abrasion testing was carried out as follows using the Taber Abraser instrument model 503:
grindstone CS 10; load 2 xl kg; 1000 revolutions with 80%
suction.
h) Crosshatch: testing was in accordance with DIN 53 151 i) Erichsen indentation: testing was in accordance with ISO 1520 j) Acetone/MEK test: an iron panel of grade St 1405 was coated with the formulation or dispersion to be tested. After drying, a plug of cotton soaked in acetone was rubbed backward and forward over a selected site of the coated panel under slight pressure (1 xforward, 1 xbackward comprises 1 double stroke DS). The test is carried out for 50 - 100 Dss.
Where the film has not been worn away after that, it is regarded as being crosslinked or fully cured.

35 k) Sulfuric acid test 28% strength: this was carried out as described by Dr. Kurt Herberts (DKH), Wuppertal, as follows:
a small plug of cotton which had been soaked in the above acid was placed on the test specimen. After 4 hours at 60~C
in a convection oven, the sample was then assessed in accordance with DIN 53 230 Tab. 1 with a score from 0 to 5 (0 = very good, 5 = poor).

1) Sulfuric acid test 38% strength and sodium hydroxide solution test 1 and 5% strength: the test was carried out as for method i), with storage being at room temperature for 24 hours.

m) Viscosity:

The flow time was determined in accordance with DIN 53 211 using a DIN 4 cup.

n) Adhesive strength:

The adhesive strength was assessed via the Tesa tear-off method, in %. In this test a strip of adhesive tape of 20 - 25 mm in width (Tesafilm 104 - Beiersdorf AG) was stuck to the print to be tested, pressed down uniformly and pulled off sharply. Testing was carried out firstly after drying and secondly after storage in water.

o) Wet-wiping strength:

The print was placed while still wet on a smooth, Rolid substrate. Under slight pressure, it was wiped with a soft moist paper cloth 50 times in the same direction. An assessment was made visually of whether and to what extent the paper had become colored and/or the print had been wiped off from the substrate.

p) Wet-rub creasing resistance:

Testing was carried out following the testing of wet adhesion by subjecting a knife-coated film to circular rubbing 20 times "under water" against an identical film.
q) Wet adhesion:

The dried, knife-coated film was placed in a bucket of water.
~y gentle rubbing of the coating "in water" using the thumb, an assessment was made of whether the wet coating could be rubbed off from the substrate or not. Testing was carried out after 30 minutes and 24 hours of storage in water.
40 r) Gloss: the gloss was assessed visually.
s) Leveling: the leveling was assessed visually.

Claims (13)

We claim:

1. An aqueous dispersion comprising a polyurethane (A) including structural units derived from compounds of the formula (I) where R1, R2 and R3 are each hydrogen, C1-C24-alkyl or C6-C24-alkenyl, R4 is hydrogen, R5 and R6 a) together are C4-C10-alkanediyl, b) are each C2-C10-alkyl, C5-C8-cycloalkyl or C7-C20-aralkyl, c) are each a hydroxyl-terminated poly(C2-C4-alkylene oxide), or d) one radical, R5 or R6, is as defined under (a) to (c) and the other radical is hydrogen or is of the formula II

where X is C2-C6-alkanediyl and R7 is as defined for R5 or R6 but is not of the formula II, and - R5 and R6 in each of the cases (a) to (d) carry a total of 2-5 hydroxyls attached to aliphatic carbons, and - R5 and/or R6 may carry 1 or 2 hydroxyls attached to aromatic structures or may carry one nitrile, tertiary amino, carboxyl or sulfo group in free or salt form.

2. A dispersion as claimed in claim 1, comprising structural units derived from compounds of the formula I where the sum of the hydroxyls which are attached to aliphatic carbons and carried in total by R5 and R6 is 2 (compounds Ia).

3. A dispersion as claimed in claim 1 or 2, wherein the carbonyl content of the structural units in the polyurethane that are derived from compounds of the formula (I) is from 3 to 140 mmol per 100 g of polyurethane (A).

4. A process for preparing a dispersion as claimed in any of claims 1 to 3, comprising the steps of I. preparing a polyurethane or isocyanato-containing polyurethane prepolymer by reacting a) polyfunctional isocyanates of 4 to 30 carbons, b) polyols of which b1) 10-100 mol%, based on the overall amount of polyols (b), have a molecular weight of 500-5000, and b2) 0-90 mol%, based on the overall amount of polyols (b), are difunctional and have a molecular weight of 62-500 g/mol, c) compounds of the formula I and/or condensation products which carry alcoholic hydroxyls and include structural elements derived from compounds of the formula (I) (condensates I), d) if desired, further polyfunctional compounds which are different from the monomers (b) and (c) and have reactive groups selected from alcoholic hydroxyl, primary amino and secondary amino, and e) monomers which are different from (a), (b), (c) and (d), have at least one isocyanate group or at least one isocyanato-reactive group and, moreover, carry at least one hydrophilic or potentially hydrophilic group which renders the polyurethane dispersible in water, II. dispersing the polyurethane or isocyanato-containing polyurethane prepolymer resulting from step I in water.

5. A process for preparing a dispersion as claimed in either of claims 2 and 3, which comprises employing as condensates (I) a carbonyl-containing polyesterpolyol having a molecular weight of from 300 to 5000 which is obtainable by polycondensation of x) compounds of the formula I in which the sum of the hydroxyls which are attached to aliphatic carbons and are carried jointly by substituents R5 and R6 is 2 (compounds Ia) and y) if desired, diols other than the compounds (Ia), having a molecular weight of 62-500 g/mol (diols y) z) with dicarboxylic acids, the molar ratio of the sum of the compounds (Ia) and the diols (y) to the dicarboxylic acids being from 2:1 to 1.05:1.

6. An aqueous dispersion as claimed in claim 1, comprising in addition to the polyurethane (A) a crosslinker (B) having at least one aldehyde group or at least 2 functional substituents selected from a group consisting of primary amino, secondary amino, hydrazine group, hydrazide group, isocyanate group, blocked isocyanate group, N-methylol group and aminooxy group.

7. A dispersion as claimed in claim 6, wherein the amounts of components (A) and (B) are chosen such that the molar ratio of the carbonyl groups of the structural elements derived from the compounds of formula (I) to the functional substituents of the crosslinker (B) is from 0.5:1 to 5:1.

8. A dispersion as claimed in any of claims 1 - 7, comprising (I) 15 - 30% by weight of a binder consisting essentially of the polyurethane (A) and the crosslinking agent (B) (II) 7 - 15% by weight of a pigment (III) 2 - 5% by weight of an alcohol suitable as solvent (IV) 4.5 - 10% by weight of customary additives (V) 45 - 70% by weight of water.

9. A dispersion as claimed in claim 8, comprising polyhydrazides as crosslinker (B).

10. A method of coating wood, glass, plastic, leather, paper or metal, which comprises applying a dispersion as claimed in any of claims 6 to 9 to one of said substrates and drying this coating.

11. A method of printing paper or metal foils or polymer films, which comprises printing it with a dispersion obtained in claim 8 or 9.

12. A method as claimed in claim 11, wherein the substrate printed is a polymer film with a surface tension of from 30 to 50 mN/m.

13. An article obtainable by a method as claimed in any of claims 10 to 12.