DE19816527A1 - Latent crosslinking aqueous dispersion comprising carbodiimide containing polyurethane - Google Patents

Abstract

A latent cross-linking aqueous polyurethane dispersion (PD) contains (I) a dispersed phase containing (Ia) a polyurethane having hydrophilic groups to effect dispersibility in water in addition to carbodiimide groups and no carboxyl groups or (Ib) a physical mixture of (Ibi) a polyurethane having hydrophilic groups to effect dispersibility in water and no carbodiimide or carboxyl groups and (Ibii) a carbodiimide containing no hydrophilic groups (II) a dispersed phase containing a polymer containing carboxyl groups but no carbodiimide groups. Also claimed are articles of wood, metal, textiles, leather or plastic that have been bonded, impregnated or coated using the dispersion (PD).

Description

Containing latent crosslinking aqueous polyurethane dispersions

• I. a disperse phase (P. I) containing a polyurethane (a), that in addition to hydrophilic groups that disperse the water effectability, carries carbodiimide groups and im carries essentially no carboxyl groups and
• II. A disperse phase (P. II) containing another polymer, which carries essentially no carbodiimide groups.

Furthermore, the invention relates to the use of the Invention appropriate aqueous dispersions as impregnating agents, Coating agent or glue as well as using the impregnated, coated or glued objects.

Aqueous dispersions in dispersed form a polyurethane included are generally known. So that coatings that the polyurethane, especially good mechanical These dispersions have properties Crosslinker component too. It is particularly desirable that the First crosslinkers the molecular weight build-up of the polyurethane causes when the polyurethane dispersion after application to the workpiece to be coated is already filmed. Under these You may get films that have a particularly high cohesion have, because then the polymer molecules of a dispersion particle with the polymer molecules of another neighboring one Dispersion particles can be linked via a covalent bond can.

A particularly good cohesion of the films is, for example, on the Adhesive area especially necessary if the adhesive adhesive mechanically loaded under the influence of heat.

To get adhesive bonds, even under these conditions still have sufficient strength, z. B. in the EP-A-206059 recommended the dispersions shortly before their Processing as an adhesive as a crosslinker a water emulsifiable Add polyisocyanate.  

The disadvantage of these two-component systems, however, is that that the pot life, d. H. the period in which these systems post their mixing can be processed, is narrowly limited. There the two-component system does not last for a longer period can be stored away and the processor has a specific one Amount of adhesive that he processes within a working cycle can, must produce, is the workload for the Processors of the adhesives in two-component systems One-component systems increased.

From US 4977219 and 5 117 059 mixtures of an aqueous gene dispersion of a carbodiimide known, the dispersion stabilized with the help of usual surface-active substances and an aqueous dispersion of an emulsion polymer with carboxylate groups.

US 5574083 relates to a mixture of an aqueous dispersion of carbodiimides, the dispersion by hydrophilic polyal kylene oxide residues that carry the carbodiimides is stabilized. These dispersions are combined with aqueous dispersions Emulsion polymers mixed with carboxylate groups.

EP-A-792908 contains mixtures of an aqueous dispersion of a carboxyl group-bearing polyurethane and an aqueous Dispersion of a carbodiimide known, the dispersion with Is stabilized using conventional surface-active substances.

According to the teaching of the 4 aforementioned documents, the carbo effect diimide an increase in the molecular weight of the carboxyl groups polymers with which they are mixed. The firmness of bonds produced with these dispersions in particular in the warmth, however, leaves something to be desired. Still is the pot life of such mixtures is limited.

The unpublished German patent application 197 33 044.4 relates to aqueous dispersions of a polyurethane, the Carbodii mid-groups.

The object of the present invention was therefore a further one-component polyurethane dispersion available do not have the disadvantages of the prior art having. In particular, they are said to have good storage stability exhibit and the production of heat-resistant bonds enable.  

Accordingly, the aqueous dispersions defined at the outset found.

The disperse phase (P. I) generally contains 0.01 to 1 5 contain, preferably 0.1 to 0.5, particularly preferably 0.15 to 0.4 mol of carbodiimide groups per kg to build up the Polyurethanes (a) monomers used.

Suitable polyurethanes (a) are, for example, in EP-A-792908 described.

Basically, all polyurethanes (a) come into consideration as hydrophilic poly urethanes, in the construction of which monomers with carbodiimide structural units are preferably used. The Carbodii mid structural units are preferably introduced into the polyurethane (a) via polyisocyanates (a1.1) containing one or more of the carbodiimide structural units. Such polyiso cyanates (a1.1) preferably obey general formula I.

in which n is a number from 1 to 20, preferably 2 to 10.

In general, the polyurethanes (a) are made up of

• a1) diisocyanates, the
  • a1.1) contain carbodiimide structural units and
    if applicable,
  • a1.2) which are free from carbodiimide structural units,
• a2) Diols, of which
  • a2.1) 10 to 100 mol%, based on the total amount of diols (b), have a molecular weight of 500 to 5000, and
  • a2.2) 0 to 90 mol%, based on the total amount of diols (a2), have a molecular weight of 60 to 500 g / mol,
• a3) with monomers different from monomers (a1) and (a2) at least one isocyanate group or at least one group reactive towards isocyanate groups which is above at least one hydrophilic group or one poten tially hydrophilic group, which causes the water disper yawability of the polyurethanes is effected,
• a4) optionally further of the monomers (a1) to (a3) various multivalent compounds with reactive Groups that are alcoholic hydroxyl groups, primary or secondary amino groups or isocyanate groups acts and
• a5) optionally different from the monomers (a1) to (a4) monovalent compounds with a reactive group, which is an alcoholic hydroxyl group, a primary or secondary amino group or an isocyanate group acts.

Suitable diisocyanatocarbodiimides (a1.1) are, for example, those of the general formula (II)

OCN- (R ¹ -N = C = N) _m -R ¹ -NCO (II)

in R ¹ for a divalent hydrocarbon radical which may have urethane, ester and / or ether groups, such as the terminal polymer by removing the isocyanate groups from a simple organic isocyanate or a urethane group and optionally containing ether or ester groups Isocyanate groups, is obtained, and when there are several R ¹ radicals in the same molecule, different R ¹ radicals corresponding to the definition mentioned can also be present at the same time
m stands for a whole or (on statistical average) fractional number from 1 to 20, preferably from 2 to 10.

The R ¹ radicals are preferably derived from the abstraction of the isocyanate groups from monomers (a1.2), which are the diisocyanates which are customarily used in polyurethane chemistry.

Particularly worth mentioning as monomers (a1.2) are diisocyanates X (NCO) ₂ , where X is an aliphatic hydrocarbon radical having 4 to 12 carbon atoms, a cycloaliphatic or aromatic hydrocarbon radical having 6 to 15 carbon atoms or an araliphatic hydrocarbon radical having 7 to 15 carbons atoms of matter stands. Examples of such diisocyanates are tetra methylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 1,4-diisocyanatocyclohexane, 1-isocyanato-3,5,5-tri methyl-5-isocyanatomethylcyclohexane (IPDI), 2,2-bis (4-iso cyanatocyclohexyl) propane, trimethylhexane diisocyanate, 1,4-diiso cyanatobenzene, 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, 4,4'-diisocyanato-diphenylmethane, 2,4'-diisocyanato-diphenylmethane, p-xylylene diisocyanate, tetramethylxylylene diisocyanate (TMXDI ), the isomers of bis (4-isocyanatocyclohexyl) methane (HMDI) such as the trans / trans, the cis / cis and the cis / trans isomer and mixtures consisting of these compounds. The carbodiimides of TMXDI are particularly preferred, especially those of the general formula I.

The radicals R ¹ , which are obtained by abstraction of the isocyanate groups from a urethane group, optionally ether or ester groups and terminal prepolymer containing isocyanate groups, are preferably those which consist of the diols (a2) and the diisocyanates (a1.2 ) are built up.

The preparation of the monomers (a1.1) is known per se and is e.g. B. in US 2 840 589, 2 941 966 EP-A-628 541 and by P.W. Campbell and K.C. Smeltz in Journal of Organic Chemistry, 28, 2069 (1963). Particularly gentle and free of side products can also be diisocyanatocarbodiimides Heterogeneous catalysis according to the German disclosure document Produce 25 04 400 and 25 52 350. Carbodiimidization of Diisocyanates in the presence of very small amounts of phospholine oxide with subsequent blocking of the catalyst Acid chlorides are described in DE-OS 26 53 120.

In general, the diisoocyanates (a1.2) except for the manufacture the diisocyanates (a1.1) are also used directly to build up the polyure thane contained in polyurethane dispersions according to the invention are used because there is often more to build the polyurethanes Isocyanate is needed as to introduce the carbodiimide Groups is required.  

For the structure of the polyurethanes, one can use compounds (a1.2) in addition to the aforementioned also use isocyanates which in addition to free isocyanate groups further blocked isocyanate groups, e.g. B. Wear uretdione groups.

With regard to good film formation and elasticity come as diols (a2) primarily higher molecular weight diols (a2.1) into consideration, the a molecular weight of about 500 to 5000, preferably about Have 1000 to 3000 g / mol.

The diols (a2.1) are in particular polyester polyols which, for. B. from Ullmann's Encyclopedia of Industrial Chemistry, 4th Edition, Volume 19, pp 62 to 65 are known. Polyester polyols are preferably used, which are obtained by reacting dihydric alcohols with dihydric carboxylic acids. Instead of the free polycarboxylic acids, the corresponding polycarboxylic acid anhydrides or corresponding polycarboxylic acid esters of lower alcohols or their mixtures can also be used to prepare the polyester polyols. The polycarboxylic acids can be aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic and optionally - e.g. B. by halogen atoms, substituted and / or unsaturated. Examples include: suberic acid, azelaic acid, phthalic acid, isophthalic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrachlorophthalic anhydride, endomethylene tetrahydrophthalic anhydride, glutaric anhydride, maleic acid, maleic acid, fatty acid, maleic acid, maleic acid, fatty acid, maleic acid, maleic acid, maleic acid, fatty acid, maleic acid, maleic acid, fatty acid, maleic acid, maleic acid, fatty acid, maleic acid, maleic acid, fatty acid, maleic acid, maleic acid, fatty acid, maleic acid, maleic acid, fatty acid, maleic acid, maleic acid, fatty acid, maleic acid, maleic acid, fatty acid, maleic acid, maleic acid, fatty acid, maleic acid, in, in. Preferred are dicarboxylic acids of the general formula HOOC- (CH ₂ ) _y -COOH, where y is a number from 1 to 20, preferably an even number from 2 to 20, e.g. B. succinic acid, adipic acid, sebacic acid and dodecanedicarboxylic acid.

As polyhydric alcohols such. B. 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, neopentyl glycol, bis (hydroxy methyl) cyclohexanes such as 1,4-bis (hydroxymethyl) cyclohexane, 2-methyl propane-1,3-diol, methyl pentanediols, also diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, Polypropylene glycol, dibutylene glycol and poly butylene glycols into consideration. Alcohols of the general formula HO- (CH ₂ ) _x -OH are preferred, where x is a number from 1 to 20, before being an even number from 2 to 20. Examples include ethylene glycol, butane-1,4-diol, hexane-1,6-diol, octane-1,8-diol and dodecane-1,12-diol. Neopentyl glycol is also preferred.

Also come polycarbonate diols, such as z. B. by Implementation of phosgene with an excess of that as a build-up components for the low molecular weight polyester polyols Alcohols can be obtained.

Lactone-based polyester diols are also suitable, these being homopolymers or copolymers of lactones, preferably end products which contain hydroxyl groups and which are lactone addition products onto suitable difunctional starter molecules. Suitable lactones are preferably those which are derived from compounds of the general formula HO- (CH ₂ ) _z -COOH, where z is a number from 1 to 20 and an H atom of a methylene unit is also by a C ₁ - bis C ₄ alkyl radical may be substituted.

Examples are epsilon-caprolactone, beta-propiolactone, gamma-Bu tyrolactone and / or methyl epsilon caprolactone and their Mixtures. Suitable starter components are e.g. B. the above mentioned as a structural component for the polyester polyols molecular dihydric alcohols. The corresponding polymer Sates of epsilon caprolactone are particularly preferred. Also lower polyester diols or polyether diols can be used as starters Production of the lactone polymers can be used. Instead of Polymers of lactones can also contain the corresponding chemically equivalent polycondensates of the lactones corresponding hydroxycarboxylic acids can be used.

In addition, the monomers (a2.1) are polyether diols. They are in particular by polymerization of ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide or epichlorohydrin with themselves, for. B. in the presence of BF ₃ or by addition of these compounds, optionally in a mixture or in succession, to starting components with reactive hydrogen atoms, such as alcohols or amines, for. B. water, ethylene glycol, propane-1,2-diol, propane-1,3-diol, 1,2-bis (4-hydroxydi phenyl) propane or aniline available. Polytetrahydrofuran with a molecular weight of 240 to 5000, and especially 500 to 4500, is particularly preferred.

Polyhydroxyolefins are also suitable, preferably those with 2 terminal hydroxyl groups, e.g. B. alpha, omega dihydroxypoly butadiene, alpha, omega-dihydroxypolymethacrylic ester or alpha, omega-dihydroxypolyacrylic esters as monomers (a2.1). Such Compounds are known for example from EP-A-0622378. Other suitable polyols are polyacetals, polysiloxanes and Alkyd resins.  

The polyols can also be used as mixtures in a ratio of 0.1: 1 to 1: 9 can be used.

The hardness and elastic modulus of the polyurethanes can be increase if as the diols (a2) in addition to the diols (a2.1) still lower molecular diols (a2.2) with a molecular weight of about 62 to 500, preferably from 62 to 200 g / mol, are used.

The structural components of the. Are used as monomers (a2.2) for the production of polyester polyols called short-chain Alkanediols used, the unbranched diols with 2 to 12 carbon atoms and an even number of carbon atoms as well Pentane-1,5-diol and neopentyl glycol are preferred.

The proportion of the diols is preferably (a2.1), based on the Total amount of diols (a2) 10 to 100 mol% and the proportion of Monomers (a2.2), based on the total amount of diols (a2) 0 to 90 mol%. The ratio of the diols is particularly preferably (a2.1) to the monomers (a2.2) 0.1: 1 to 5: 1, especially before increases 0.2: 1 to 2: 1.

In order to achieve the water dispersibility of the polyurethanes, In addition to components (a1) and (2), the polyurethanes are made of from the components (a1) and (a2) different monomers (a3) which at least one isocyanate group or at least one opposite Isocyanate group reactive group and moreover at least a hydrophilic group or a group that is in a hydro let phile group convince, carry, built. Hereinafter Text becomes the term "hydrophilic groups or potentially hydrophilic groups "with" (potentially) hydrophilic groups " abbreviated. The (potentially) hydrophilic groups react with Isocyanates much slower than the functional groups of the monomers that are used to build the main polymer chain.

The proportion of components with (potentially) hydrophilic groups on the total amount of components (a1), (a2), (a3), (a4) and (a5) is generally dimensioned so that the molar amount of (Potentially) hydrophilic groups, based on the amount by weight of all monomers (a1) to (a5), 30 to 1000, preferably 50 to 500 and is particularly preferably 80 to 300 mmol / kg.

The (potentially) hydrophilic groups can be non-ionic or preferably around (potentially) ionic hydrophilic group pen act.  

Particularly suitable nonionic hydrophilic groups are poly (C ₁ -C ₄ -alkylene) glycol ethers composed of preferably 5 to 100, preferably 10 to 80, repeating ethylene oxide units. The content of polyethylene oxide units is generally 0 to 10, preferably 0 to 6% by weight, based on the amount by weight of all monomers (a1) to (a5).

Preferred monomers with nonionic hydrophilic groups are Polyethylene oxide diols, polyethylene oxide monools and the reaction products from a polyethylene glycol and a diisocyanate, the carry a terminally etherified polyethylene glycol residue. Derar term diisocyanates and processes for their preparation are in the patents US 3 905 929 and US 3 920 598.

Ionic hydrophilic groups are mainly anionic groups such as the sulfonate, carboxylate and phosphate groups in the form their alkali metal or ammonium salts and cationic groups such as ammonium groups, especially protonated tertiary Amino groups or quaternary ammonium groups.

Potentially ionic hydrophilic groups are primarily those that by simple neutralization or hydrolysis reactions convert the above-mentioned ionic hydrophilic groups leave, e.g. B. carboxylic acid groups.

(Potentially) ionic monomers (a3) are e.g. B. in Ullmanns Encyclopedia of Technical Chemistry, 4th Edition, Volume 19, Pp. 311-313 and for example in DE-A 14 95 745 in detail described.

Above all, as (potentially) cationic monomers (a3) Monomers with tertiary amino groups of particularly practical Meaning, for example: tris (hydroxyalkyl) amines, N, N'-bis (hydroxyalkyl) alkylamines, N-hydroxyalkyl dialkylamines, Tris (aminoalkyl) amines, N, N'-bis (aminoalkyl) alkylamines, N-ami noalkyl-dialkylamine, the alkyl radicals and alkanediyl unit ten of these tertiary amines independently 1 to 6 carbon atoms exist.

These tertiary amines are either with acids, preferably strong mineral acids such as phosphoric acid, sulfuric acid, halogenic acids or strong organic acids or by reaction with suitable quaternizing agents such as C ₁ - to C ₆ -alkyl halides or benzyl halides, for. B. bromides or chlorides in the ammonium salts.

Suitable monomers with (potentially) anionic groups are usually aliphatic, cycloaliphatic, araliphatic or aromatic carboxylic acids and sulfonic acids which carry at least one alcoholic hydroxyl group or at least one primary or secondary amino group. Dihydroxyalkylcarboxylic acids are preferred, especially those with 3 to 10 carbon atoms, as are also described in US Pat. No. 3,412,054. In particular, compounds of the general formula (III)

in which R ¹ and R ^{2 is} a C ₁ - to C ₄ -alkanediyl unit and R ^{3 is} a C ₁ - to C ₄ -alkyl unit and especially dimethylol propionic acid (DMPA) is preferred.

Corresponding dihydroxysulfonic acids and Dihydroxyphosphonic acids such as 2,3-dihydroxypropanephosphonic acid.

Otherwise, dihydroxyl compounds with one molecule are suitable Lar weight over 500 to 10,000 g / mol with at least 2 carboxylate groups known from DE-A 39 11 827. you are through Implementation of dihydroxyl compounds with tetracarboxylic acid dianhy three such as pyromellitic dianhydride or cyclopentantetracarbon acid dianhydride in a molar ratio of 2: 1 to 1.05: 1 in one Polyaddition reaction available. As dihydroxyl compounds are in particular the monomers (b2) listed as chain extenders as well as the diols (b1).

As monomers (a3) with amino groups reactive towards isocyanates Pen come aminocarboxylic acids such as lysine, ß-alanine or those in the DE-A-20 34 479 adducts of aliphatic diprimaries Diamines on α, β-unsaturated carboxylic or sulfonic acids in Consideration.

Such compounds obey, for example, the formula (IV)

H ₂ NR ⁴ -NH-R ⁵ -X (IV)

in the
R ⁴ and R ⁵ independently of one another for a C ₁ - to C ₆ -alkanediyl unit, preferably ethylene
and X represents COOH or SO ₃ H.

Particularly preferred compounds of formula (IV) are N- (2-aminoethyl) -2-aminoethane carboxylic acid and the N- (2-amino ethyl) -2-aminoethanesulfonic acid or the corresponding alkali salts, Na being particularly preferred as the counter ion.

The adducts of the abovementioned are also particularly preferred aliphatic diprimary diamines on 2-acrylamido-2-methylpropane sulfonic acid as z. B. in DE patent specification 19 54 090 are described.

If monomers with potentially ionic groups are used can be converted into the ionic form before, during, but preferably after the isocyanate polyaddition, because the ionic monomers in the reaction mixture often only difficult to solve. The sulfonate or Carboxylate groups in the form of their salts with an alkali ion or an ammonium ion as a counter ion.

In the case of the use of monomers (a3) with carboxyl groups or those groups which can be transferred into the carboxyl groups after the dispersion of the polyurethanes by hydrolysis reactions or protonation of carboxylate groups, the pH of the aqueous dispersion according to the invention is adjusted so basic that in essentially no more carboxyl groups are present but these are practically completely neutralized. This is generally the case with pH << pKs, the following applies:
pH = pKs-log c _acid / c _salt .

The monomers (a4) which differ from the monomers (a1) to (a3) these are generally used for networking or chains renewal. There are generally no more than two-valued ones phenolic alcohols, amines with 2 or more primary and / or secondary amino groups as well as compounds in addition to one or several alcoholic hydroxyl groups one or more primary and / or wear secondary amino groups.

Alcohols with a higher valence than 2, for adjustment a certain degree of branching or networking can, for. B. trimethylolpropane, glycerin or sugar.  

Also suitable are monoalcohols which, in addition to the hydroxyl Group carry another isocyanate-reactive group such as monoalcohols with one or more primary and / or secondary amino groups, e.g. B. Monoethanolamine.

Polyamines with 2 or more primary and / or secondary amino groups pen are mainly used when the chain extension or crosslinking should take place in the presence of water, since Amines usually faster than alcohols or water with Isocya naten react. This is often necessary when watery Dispersions of cross-linked polyurethanes or with polyurethanes high molecular weight may be desired. In such cases, this is how it is done before preparing prepolymers with isocyanate groups, these quickly dispersed in water and then by adding Compounds with several isocyanate-reactive amino groups extended or networked.

Suitable amines are generally polyfunctional amines of the molecular weight range from 32 to 500 g / mol, preferably from 60 to 300 g / mol, which selected at least two amino groups from the group of primary and secondary amino groups Examples of this are diamines such as diaminoethane and diamino propanes, diaminobutanes, diaminohexanes, piperazine, 2,5-dimethyl piperazine, amino-3-aminomethyl-3,5,5-trimethyl-cyclohexane (Iso phorondiamine, IPDA), 4,4'-diaminodicyclohexylmethane, 1,4-diamino cyclohexane, aminoethylethanolamine, hydrazine, hydrazine hydrate or Triamines such as diethylenetriamine or 1,8-diamino-4-aminomethyl octane.

The amines can also be in blocked form, e.g. B. in the form of ent speaking ketimines (see e.g. CA-A-1 129 128), ketazines (cf. e.g. B. US-A 4 269 748) or amine salts (see US-A 4 292 226) be used. Also oxazolidines, as for example in of US-A 4 192 937 are capped polyamines represents the production of the polyurethanes of the invention can be used to extend the chain of the prepolymers. When using such capped polyamines, they become generally with the prepolymers in the absence of water mixed and then this mixture with the Dispersionswas water or part of the dispersion water mixed so that the corresponding polyamines are released hydrolytically.

Mixtures of di- and triamines are preferably used, mixtures of isophoronediamine (IPDA) and Diethylene triamine (DETA).  

The polyurethanes preferably contain 1 to 30, especially preferably 4 to 25 mol%, based on the total amount of the compo nenten (b) and (d) of a polyamine with at least 2 opposite Isocyanate-reactive amino groups as monomers (d).

Alcohols with a higher valence than 2, for adjustment a certain degree of branching or networking can, for. B. trimethylolpropane, glycerin or sugar.

For the same purpose, monomers (a4) can also be higher than divalent isocyanates are used. Commercial verb Examples are the isocyanurate or the biuret of the Hexamethylene diisocyanate.

Monomers (a5), which may also be used, are mono isocyanates, monoalcohols and mono-primary and secondary amines. in the in general, their proportion is at most 10 mol%, based on the total molar amount of monomers. This monofunctional connection gene usually carry other functional groups such as olefi African groups or carbonyl groups and serve to introduce functional groups in the polyurethane that the dispersion or the crosslinking or further polymer-analogous implementation of the Allow polyurethane. Monomers such as Isopropenyl-alpha, alpha-dimethylbenzyl isocyanate (TMI) and esters of acrylic or methacrylic acid such as hydroxyethyl acrylate or Hydroxyethyl methacrylate.

In the field of polyurethane chemistry, it is well known how the molecular weight of the polyurethanes by choosing the proportions of the mutually reactive monomers and the arithmetic mean the number of reactive functional groups per molecule can be adjusted.

Normally, components (a1) to (a5) and their respective molar amounts are chosen so that the ratio A: B with

• A) the molar amount of isocyanate groups and
• B) the sum of the molar amount of the hydroxyl groups and the Molar amount of the functional groups with isocyanates in can react to an addition reaction.

0.5: 1 to 2: 1, preferably 0.8: 1 to 1.5, particularly preferably 0.9: 1 to 1.2: 1. That is very particularly preferred Ratio A: B as close as possible to 1: 1.  

The monomers (a1) to (a5) used bear on average usually 1.5 to 2.5, preferably 1.9 to 2.1, particularly preferably 2.0 isocyanate groups or functional groups with Isocyanates can react in an addition reaction.

The polyaddition of components (a1) to (a5) generally takes place mean at reaction temperatures of 20 to 180 ° C, preferred 50 to 150 ° C under normal pressure or under autogenous pressure.

The required response times can be a few minutes extend to a few hours. It is in the field of Polyurethane chemistry is known as the reaction time through a Variety of parameters such as temperature, concentration of the Monomers, reactivity of the monomers is affected.

To accelerate the reaction of the diisocyanates, the usual Chen catalysts such as dibutyltin dilaurate, stannous octoate or Diazabicyclo- (2,2,2) octane can also be used.

Stirred tanks are suitable as polymerization apparatus especially when using solvents ensures low viscosity and good heat dissipation is.

Preferred solvents are infinitely miscible with water, have a boiling point at normal pressure of 40 to 100 ° C and do not react or react only slowly with the monomers.

Most often the dispersions are made according to one of the following Process made:

After the "acetone process" is in a miscible with water and at normal pressure below 100 ° C boiling solvent from the Components (a1) to (a3) made an ionic polyurethane. So much water is added until a dispersion forms, in which water is the coherent phase.

The "prepolymer mixing process" differs from acetone proceed in that not a fully reacted (potentially) ioni cal polyurethane, but first a prepolymer that carries isocyanate groups. The components are here chosen so that the defined ratio A: B is greater than 1.0 to 3, preferably 1.05 to 1.5. The prepolymer comes first dispersed in water and then optionally by reak tion of the isocyanate groups with amines that are more than 2 opposite Wear isocyanate-reactive amino groups, crosslinked or with amino NEN which carry 2 amino groups reactive towards isocyanates,  chain extended. A chain extension also takes place if no amine is added. In this case, isocyanate groups hydrolyzed to amino groups, with those still remaining Isocyanate groups of the prepolymers with chain extension react.

Usually, if in the manufacture of the polyurethane a solvent was used, most of the Solvent removed from the dispersion, for example by Distillation under reduced pressure. Preferably, the Dispersions have a solvent content of less than 10% by weight and are particularly preferably free of solvents.

The dispersions generally have a solids content of 10 to 75, preferably 20 to 65% by weight and a viscosity of 10 to 500 m Pas (measured at a temperature of 20 ° C. and a shear rate of 250 s ^-1 ).

Hydrophobic aids that can be difficult to homogenize to be distributed in the finished dispersion, for example Phenol condensation resins made from aldehydes and phenol or phenol derivatives or epoxy resins and other z. B. in DE-A-39 03 538, 43 09 079 and 40 24 567 polymers mentioned in polyurethane dispersions serve, for example, as adhesion improvers, can be described according to the two fonts mentioned above The methods already mentioned are the polyurethane or the prepolymer be added to the dispersion.

As a polymer (P) contained in the disperse phase (P. II), virtually all film-forming polymers come in Consider carboxyl groups.

Those aqueous dispersions according to the invention in which phase (P. II) is essentially formed from are particularly preferred

• IIa) a polyurethane (b), the carboxyl groups and im carries essentially no carbodiimide groups or
• IIb) a polymer (c) which is derived from
  • c1) 30 to 99.9% by weight of main monomers selected from C ₁ to C ₂₀ alkyl (meth) acrylates, vinyl esters of carboxylic acids containing up to 20 C atoms, vinyl aromatics with up to 20 C atoms, ethylenically unsaturated nitriles , Vinyl halides and aliphatic hydrocarbons with 2 to 8 carbon atoms and 1 or 2 double bonds,
  • c2) 0.01 to 20 wt .-% of a carboxylic acid with an olefinic double bond and
  • c3) of (c1) and (c2) different radically polymerizable monomers or
• IIc) a water-soluble or water-dispersible polyester, which carries carboxyl groups (polymer d)

In connection with the polymers (c) is (meth) acrylic ver shortening for methacrylic or acrylic.

The polyurethanes (b) preferably contain 0.01 to 1, preferably 0.1 to 0.5, mol of carboxyl groups per kg of polyurethane (b). The number of carboxyl groups in the polyurethane (b) and that of the carbodiimide structural units in the polyurethane (a) is particularly preferably largely equivalent
The polyurethanes (b) are generally and preferably composed of

• b1) Diisocyanates that are free of carbodiimide structure units
• b2) diols, of which
  • b2.1) 10 to 100 mol%, based on the total amount of diols (b2), have a molecular weight of 500 to 5000, and
  • b2.2) 0 to 90 mol%, based on the total amount of diols (b2), have a molecular weight of 60 to 500 g / mol,
• b3) with monomers different from the monomers (b1) and (b2) at least one isocyanate group or at least one group reactive towards isocyanate groups which is above at least one hydrophilic group or one poten tiell hydrophilic group wear, causing the water dispersibility of the polyurethanes is effected, it at least in part of the monomers (b3) in the hy drophilic group or potentially hydrophilic group by one Carboxyl group or a potential carboxyl group, which is able after the dispersion of the polyure thans spontaneously into an acidic watery environment React carboxyl group.  
• b4) optionally further of the monomers (b1) to (b2) various multivalent compounds with reactive Groups that are alcoholic hydroxyl groups, primary or secondary amino groups or isocyanate groups acts and
• b5) optionally different from the monomers (b1) to (b4) monovalent compounds with a reactive group, which is an alcoholic hydroxyl group, a primary or secondary amino group or an isocyanate group acts.

As structural components (b1), there are in particular those as (a1.2) considered connections as structural components (b2) those as (a2), as structural components (b3) as (a3), as Auf Building components come (b4) as (a4), and as building components come (b5) the compounds referred to as (a5). Both However, structural components (b3) differ from those as (a3) designated the peculiarity that at least some of the monomers (b3) in the hydrophilic group or potentially hydrophilic group around a carboxyl group or a potential carboxyl group that is able to, after the Dispersion of the polyurethane spontaneously in an aqueous environment to react with a carboxyl group.

Among potential carboxyl groups are z. B. as salts lying carboxylate groups, at least partially in water protonated, to understand and, for example, carboxylic acid anhydride groups that are hydrolyzed in water. The desired ratio of carboxyl groups to carboxylates can be adjust particularly easily after dispersion by: specifically changes the pH of the dispersion, e.g. B. as in the DE-A-43 00 162 is described, or by going before the dispergy tion and after the structure of the polyurethane (b) alkali or acid admits.

Such dispersions according to the invention are preferred, the Phase (P. I) is essentially formed from a polyurethane (a), the structure of the hydrophilic groups Component (a3) is sulfonate groups, and the phase (P. II) is essentially formed from a polyurethane (b), where the hydrophilic group of the structural component (b3) carboxyl groups mixed with sulfonate groups which partly in the form of their ammonium or alkali salts, acts.  

The polymers (c) are preferably composed of the following monomers built up.

As monomers (c1) are z. B. (meth) acrylic acid alkyl ester with a C ₁ -C ₁₀ alkyl radical, such as methyl methacrylate, methyl acrylate, n-butyl acrylate, ethyl acrylate and 2-ethylhexyl acrylate.

In particular, mixtures of the (meth) acrylic acid alkyl esters suitable.

Vinyl esters of carboxylic acids with 1 to 20 carbon atoms are e.g. B. Vinyl laurate, stearate, vinyl propionate and vinyl acetate.

As vinyl aromatic compounds come vinyl toluene, alpha and p-methylstyrene, alpha-butylstyrene, 4-n-butylstyrene, 4-n-decyl styrene and preferably styrene.

Examples of nitriles are acrylonitrile and methacrylonitrile.

The vinyl halides are substituted with chlorine, fluorine or bromine ethylenically unsaturated compounds, preferably vinyl chloride and Vinylidene chloride.

As non-aromatic hydrocarbons with 2 to 8 carbon atoms and one or two olefinic double bonds are butadiene, iso pren, and chloroprene, as well as ethylene, propylene and isobutylene called.

The main monomers (c1) are also preferably mixed used.

Vinyl aromatic compounds such as styrene are e.g. B. often mixed with C ₁ -C ₂₀ alkyl (meth) acrylates, in particular with C ₁ -C ₈ alkyl (meth) acrylates, or non-aromatic hydrocarbons such as isoprene or preferably butadiene.

Monomers (c2) are preferably (meth) acrylic acid or Maleic acid into consideration.

As monomers (c3) z. B. into consideration: esters of acrylic and Methacrylic acid of alcohols with 1 to 20 carbon atoms, which besides that Oxygen atom in the alcohol group at least one more Contain heteroatom and / or an aliphatic or aromatic ring such as 2-ethoxyethyl acrylate, 2-butoxy ethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethyl aminoethyl (meth) acrylate, (meth) acrylic acid aryl, alkaryl or Cycloalkyl esters, such as cyclohexyl (meth) acrylate, phenyl  ethyl (meth) acrylate, phenylpropyl (meth) acrylate or acrylic acid esters of heterocyclic alcohols such as furfuryl (meth) acrylate called.

In addition, monomers with amino or amide groups such as (meth) acrylamide, and their derivatives substituted on the nitrogen with C ₁ -C ₄ -alkyl, are also suitable as monomer (c3).

Of importance as monomers (c3) are especially hydroxyfunctional monomers, e.g. B. (meth) acrylic acid-C ₁ -C ₁₅ alkyl esters which are substituted by one or two hydroxyl groups. Of particular importance as hydroxy-functional comonomers are (meth) acrylic acid-C ₂ -C ₈ -hydroxyalkyl esters, such as n-hydroxyethyl, n-hydroxypropyl or n-hydroxybutyl (meth) acrylate.

The polymer (c) is produced by free radicals Polymerization. Suitable polymerization methods, such as substance, Solution, suspension or emulsion polymerization are that Known specialist.

The copolymer is preferably obtained by solution polymerization with subsequent dispersion in water or especially preferably produced by emulsion polymerization.

The comonomers can be used as usual in emulsion polymerization in the presence of a water-soluble initiator and an emulga tors are polymerized at preferably 30 to 95 ° C.

Suitable initiators are e.g. B. sodium, potassium and ammonium persulfate, tert-butyl hydroperoxides, water-soluble azo compound gene or redox initiators.

As emulsifiers z. B. Alkaline salts of longer chain fat acids, alkyl sulfates, alkyl sulfonates, alkylated aryl sulfonates or alkylated biphenyl ether sulfonates. Furthermore come as Emulsifiers Reaction products of alkylene oxides, in particular Ethylene or propylene oxide with fatty alcohols, acids or Phenol, or alkylphenols into consideration.

In the case of aqueous secondary dispersions, the copolymer first by solution polymerization in an organic Solvent produced and then with the addition of Salt formers, e.g. B. from ammonia to carboxylic acid groups tendency copolymers, in water without using a Emulsifier or dispersing agent dispersed. The organic solvents can be distilled off. The  The preparation of aqueous secondary dispersions is known to the person skilled in the art known and z. B. described in DE-A-37 20 860.

The regulator can be used to adjust the molecular weight be used. Are suitable for. B. -SH containing verb such as mercaptoethanol, mercaptopropanol, thiophenol, thio glycerin, thioglycolic acid ethyl ester, thioglycolic acid methyl ester and tert-dodecyl mercaptan, they can e.g. B. in amounts from 0 to 0.5 wt .-%, based on the copolymer, additionally used become.

The type and amount of the comonomers is preferably chosen so that that the copolymer obtained has a glass transition temperature of -60 and + 140 ° C, preferably -60 and + 100 ° C. The glass transition temperature of the copolymer is determined by differential thermal analysis or differential scanning calorimetry according to ASTM 3418/82.

The number average molecular weight M _n is preferably 10 ³ to 5.10 ⁶ , particularly preferably 10 ⁵ to 2.10 ⁶ (determined by gel permeation chromatography with polystyrene as standard).

The water-dispersible polyesters that carry carboxyl groups (Polymer d) are, for example, from Encyclopedia of polymer science and engineering, John Wiley & Sons, second edition, volume 12, pages 300 to 313.

Suitable are, for example, polyesters made from compounds of general formula (II) and the structural components of the polyester polyols, which are used to build the polyurethanes (a) (Assembly component a2.1) are manufactured.

The dispersions according to the invention are particularly simple by using dispersions containing the disperse phases (I) and (II) contain separately, and then manufacture them mixed together. The mixing is not critical and can For example, be made so that a dispersion in the other stirs. Mixing can be any Time before they are applied.

The polyurethane dispersions according to the invention can be further water emulsifiable or dispersible resins, such as polyurethanes, Polyester, epoxy or alkyd resins as well as commercially available auxiliary and additives such as blowing agents, defoamers, emulsifiers, ver thickeners and thixotropic agents, colorants such as dyes and contain pigments. Usually contain the fiction  according to dispersions, however, no effective amounts of melamine, Kaolin or flame retardant.

They are suitable, for example, for gluing or coating different substrates such as wood, metal, plastics, Paper, leather or textile, for the impregnation of textiles as well as for the production of moldings and printing inks.

The processing of the polyurethane dispersions according to the invention can be according to those in the adhesive, leather or paint industry generally customary procedures take place, i.e. by the Disperses onto the substrate, rolls or doctored and then dries.

In the case of processing as an adhesive, they are coated Workpieces either before drying the dispersion film or preferred after drying with another workpiece assembled using pressure.

You get particularly strong adhesive bonds if you Workpieces provided with a dried adhesive film are immediately before, during or after the assembly a temperature of about 50 to 100 ° C warmed.

Draw the adhesive composites produced using these methods are characterized in particular by the fact that they are stable in storage and bonds with you with a high heat resistance have it made.

Experimental part Abbreviations

Tl = parts
CDI = carbodiimide groups
OHZ = hydroxyl number
TDI = tolylene diisocyanate
HDI = hexamethylene diisocyanate
DBTL = dibutyltin dilaurate
DMPA = dimethylol propionic acid
Demineralized water = deionized water
RT = room temperature

In the examples, the carbodiimide of the following formula was used

where n is about 4 on average.

The viscosities of the dispersions were measured at a temperature of 20 ° C and a shear rate of 250 s-1 with a rota tion rheometer with concentric cylinders (spindle diameter 38.7 mm, cup diameter: 42.0 mm).

The particle size of the latex particles was determined indirectly via turbidity Measurements determined. For this purpose, the turbidity of a dispersion was measured a solids content of 0.01 wt .-% relative to dest. Water at a layer thickness of 2.5 cm and determined at room temperature.

Determination of the K value

The K value is a measure of the molecular weight of a polymer and was determined using the method described in Kirk-Othmer, Encyclopedia of Chemical Technology, 3rd Edition, Verlag John Wiley & Sons, Inc., volume 23, p. 967 is described.
A Preparation of the dispersions
A1 Preparation of the starting dispersions
A1.1 Preparation of the Initial Dispersions of Type (I)

Dispersion I.1: dispersion with carbodiimide

542.9 g of a polyester composed of adipic acid, neopentylgylcol and hexanediol (OHZ = 56), 0.1 g of DBTL and 36.6 g of 1,4-butanediol were dissolved in 92.2 g of acetone with 58.6 g of TDI at 65 for 1 h ° C implemented. Then 88.3 g of an NCO term. Carbodiimids with 8% NCO and 15% CDI in 100 g acetone were added. After 10 minutes, 56.5 g of HDI were metered in and the mixture was stirred at 65 ° C. for 153 minutes. It was diluted with 756 g of acetone and cooled to 50 ° C. The NCO content is 0.38%. It was chain extended with 33.8 g of a 50% aqueous solution of the aminoethylaminoethanesulfonic acid Na salt and dispersed with 1200 g of DI water. The acetone was distilled off in vacuo at temperatures up to 43 ° C. and the solids content was adjusted to 40%.
Analysis values: LD: 69 Visc .: 32 mPas K value: 51 pH: 8.8.

Dispersion I.2: dispersion with carbodiimide

563.2 g of a polyester composed of adipic acid, neopentylgylcol and hexanediol (OHZ = 56), 0.1 g of DBTL and 38 g of 1,4-butanediol were reacted in 91.4 g of acetone with 63.4 g of TDI at 62 ° C. for 1 hour. Then 57.3 g of an NCO-terminated carbodiimide with 8% NCO and 15% CDI in 100 g of acetone were added, after 10 minutes 61.2 g of HDI were added and the mixture was stirred at 65 ° C. for 139 minutes. It was diluted with 756 g of acetone and cooled to 50 ° C. The NCO content was 0.41%. The chain was extended with 33.8 g of a 50% strength solution of the aminoethyl-aminoethanesulfonic acid Na salt and dispersed with 1200 g of demineralized water. The acetone is distilled off in vacuo at temperatures up to 43 ° C. and the solids content is adjusted to 40%.
Analysis values: LD: 78 Visc .: 46 mPas K value: 58 pH: 8.3.

Dispersion I.3: dispersion with carbodiimide

552.6 g of a polyester composed of adipic acid, neopentylgylcol and hexanediol (OHZ = 56), 0.1 g of DBTL and 37.3 g of 1,4-butanediol were mixed in 91.4 g of acetone with 60.9 g of TDI at 65 ° C. for 1 h implemented. Then 73.5 g of an NCO term carbodiimide with 8% NCO and 15% CDI in 100 g of acetone were added. After 10 minutes, 58.8 g of HDI were metered in and the mixture was stirred at 65 ° C. for 140 minutes. It was diluted with 756 g of acetone and cooled to 50 ° C. The NCO content was 0.41%. It was chain extended with 33.8 g of a 50% solution of the aminoethylaminoethanesulfonic acid sodium salt and dispersed with 1200 g of demineralized water. The acetone was distilled off in vacuo at temperatures up to 43 ° C. and the solids content was adjusted to 40%.
Analysis values: LD: 80 Visc .: 50 mPas K value: 53 pH: 7.8.

Dispersion I.4 (for comparison): dispersion with carbodiimide after Dispersion before distillation

600.6 g of a polyester composed of adipic acid, neopentylgylcol and hexanediol (OHZ = 56), 0.15 g of DBTL and 40.5 g of 1,4-butanediol were dissolved in 91.4 g of acetone with 72.2 g of TDI at 65 for 1 h ° C implemented. 69.8 g of HDI were then metered in and the mixture was stirred at 65 ° C. for 199 min, diluted with 100 g of acetone. It was diluted with 765.8 g acetone and cooled to 50 ° C. The NCO content was 0.41%. It was chain extended with 33.8 g of a 50% solution of the aminoethylaminoethanesulfonic acid sodium salt and dispersed with 1200 g of demineralized water. Then 50 g of an NCO term. Carbodiimids with 8% NCO and 15% CDI in 100 g acetone were added. The acetone was distilled off in vacuo at temperatures up to 43 ° C. and the solids content was adjusted to 40%.
Analysis values: LD: 73.4 Visc .: 25 mPas K value: 59 pH: 7.0.

A1.2 Preparation of the initial dispersions of type (II) Dispersion II.1: dispersion with carboxylic acid

515.5 g of a polyester composed of adipic acid, neopentylgylcol and hexanediol (OHZ = 56), 0.5 g of DBTL, 34.5 g of DMPA and 34.8 g of 1,4-butane diol are mixed in 92% of 187.3 g of acetone with 3 g of TDI reacted for 1 h at 65 ° C. Then 89.2 g of HDI were added and the mixture was stirred at 65 ° C. for 177 min. It was diluted with 749.3 g of acetone and cooled to 30 ° C. The NCO content was 0.91%. The chain was lengthened with 67.6 g of a 50% strength solution of the aminoethylaminoethanesulfonic acid Na salt and dispersed with 1200 g of demineralized water. The acetone was distilled off in vacuo at temperatures up to 43 ° C. and the solids content was adjusted to 40%.
Analysis values: LD: 84 Visc .: 179 mPas K value: 40 pH: 5.9.

Dispersion II.2

Dispersion of butyl acrylate, acrylonitrile and acrylic acid with the Trade names Acronal® A 378.

A1.3 Production of a Dispersion of the Prior Art Type 3 without caboxyl or carbodiimide groups Dispersion III.1 without carbodiimide and without DMPA

588.7 g of a polyester of adipic acid, neopentylgylcol and hexanediol (OHZ = 56), 0.1 g DBTL, and 39.7 g 1,4-butanediol were added in 189.7 g acetone with 74.4 g TDI for 1 h 65 ° C implemented. Then 71.9 g of HDI were added and the mixture was stirred at 65 ° C. for 155 min. It is diluted with 757.5 g of acetone and cooled to 30 ° C. The NCO content was 0.65%. 50.7 g of a 50% strength solution of the aminoethyl-aminoethanesulfonic acid Na salt were chain-extended and dispersed with 1200 g of demineralized water. The acetone was distilled off in vacuo at temperatures up to 43 ° C. and the solids content was adjusted to 40%.
Analysis values: LD: 67 Visc .: 27 mPas K value: 52.2 pH: 7.9.

A.2 Preparation of the latently crosslinking dispersions and Comparative examples

The dispersions are subjected to hard fiber / PVC bonding and the heat resistance is determined.
Dispersion I.1-II.1: 50 parts of dispersion I.1 were mixed with 50 parts of dispersion II.1.
Dispersion I.1-II.1: 50 parts of dispersion I.2 were mixed with 50 parts of dispersion II.1.
Dispersion I.2-II.2: 45 parts of dispersion I.2 was mixed with 60 parts of dispersion II.2.
Dispersion I.3-II.1: 50 parts of dispersion I.3 were mixed with 50 parts of dispersion II.1.
Dispersion I.4-II.1 (V): 250 parts of dispersion 5 were mixed with 299 parts of dispersion II.1.
Dispersion III.1 isocyanate: Dispersion III.1 was mixed with 7.5% Desmodur® DA, an aliphatic polyisocyanate

B. Carrying out the application tests Static peel strength in heat-hard fiber / soft PVC

The dispersions are made with Collacral VL® to approx. 300 mPas thickened.

B.1 Preparation of the test specimens The tests were carried out according to the following test instructions

Equipment:
2 mm wire squeegee
Circulating air drying cabinet
Timepiece
heated press
Knife for cutting out the test strips
300 g weights
Substrate:
Hardboard / PVC film, type: Benecke 577 / E28
Dimension:
200 × 200 mm
Bonding area:
200 × 170 mm (divided into 5 test strips of 30 mm)
assignment
2 mm wire doctor blade on hardboard in the longitudinal direction
Drying:
3 min at 60 ° C
Gluing method:
Hot pressing at 80 ° C only PVC side
Pressure:
0.1 N / mm ²

Pressing time:
30 s
Sample storage:
1 day at RT
Test load:
300 g per 30 mm wide test strip
Peel angle:
180 °
Number of samples:
1 plate is 5 samples

B.2 Stress test and evaluation The tests were carried out according to the following test instructions

After the glue application, drying and pressing are made of the surface thus produced, 30 mm wide strips with 10 mm Cut space. Only the film is through separates, the hardboard remains undamaged. The 10 mm wide th intermediate strips are removed and the 30 mm wide Test strips clamped at 300 g weight.

The test begins at 40 ° C. After every 30 minutes the Temperature increased by 10 ° C. In the heating phase, the 15 minutes the test strips are not loaded.

Assessment of the fracture pattern

K = separation in the adhesive layer without detachment from a material (cohesive break)
C = test results.

The test results are summarized in Table 1.

Table 1

Claims (10)

1. Containing latent crosslinking aqueous polyurethane dispersions

• I. a disperse phase (P. I) containing a polyurethane (a) which, in addition to hydrophilic groups which bring about water-dispersibility, bears carbodiimide groups and essentially bears no carboxyl groups and
• II. A disperse phase (P. II) containing another polymer which carries carboxyl groups and essentially no carbodiimide groups.

2. Aqueous dispersions according to claim 1, wherein the carbodi Imide structural units introduced into the polyurethane (a) are about polyisocyanates (a1) containing one or more of the carbodiimide structural units. 3. Aqueous dispersions according to claim 1 or 2, wherein the carbodiimide structural units are introduced into the polyurethane (a) via polyisocyanates (a1) of the general formula I.
in which n is a number from 1 to 20. 4. Aqueous dispersions according to claims 1 to 3, wherein the phase (P. I) is essentially formed from a polyurethane than (a), which is composed of

• a1) diisocyanates, the
  • a1.1) contain carbodiimide structural units and
    if applicable,
  • a1.2) which are free from carbodiimide structural units,
• a2) Diols, of which
  • a2.1) 10 to 100 mol%, based on the total amount of diols (b), have a molecular weight of 500 to 5000, and
  • a2.2) 0 to 90 mol%, based on the total amount of diols (a2), have a molecular weight of 60 to 500 g / mol,
• a3) monomers different from the monomers (a1) and (a2) with at least one isocyanate group or at least one group which is reactive toward isocyanate groups and which, moreover, carry at least one hydrophilic group or a potentially hydrophilic group, thereby causing the water-dispersibility of the polyurethanes,
• a4) optionally further polyvalent compounds with reactive groups different from the monomers (a1) to (a3), which are alcoholic hydroxyl groups, primary or secondary amino groups or isocyanate groups and
• a5) if appropriate from the monomers (a1) to (a4) ver different monovalent compounds having a reactive group which is an alcoholic hydroxyl group, a primary or secondary amino group or an isocyanate group.

5. Aqueous dispersions according to claims 1 to 4, wherein the phase (P. I) is essentially formed from

• IIa) a polyurethane (b) which carries carboxyl groups and essentially no carbodiimide groups or
• IIb) a polymer (c) which is derived from
  • c1) 30 to 99.9% by weight of main monomers selected from C ₁ to C ₂₀ alkyl (meth) acrylates, vinyl esters of carboxylic acids containing up to 20 C atoms, vinyl aromatics with up to 20 C atoms, ethylenically unsaturated nitriles , Vinyl halides and aliphatic hydrocarbons with 2 to 8 carbon atoms and 1 or 2 double bonds,
  • c2) 0.01 to 20 wt .-% of a carboxylic acid with an olefinic double bond and
  • c3) of (c1) and (c2) different radically polymerizable monomers or
• IIc) a water-soluble or water-dispersible polyester which carries carboxyl groups (polymer d)

6. Aqueous dispersions according to claim 5, wherein the polyurethane (b) is composed of

• b1) Diisocyanates that are free of carbodiimide structure units
• b2) diols, of which
  • b2.1) 10 to 100 mol%, based on the total amount of diols (b2), have a molecular weight of 500 to 5000, and
  • b2.2) 0 to 90 mol%, based on the total amount of diols (b2), have a molecular weight of 60 to 500 g / mol,
• b3) Monomers different from the monomers (b1) and (b2) with at least one isocyanate group or at least one group which is reactive toward isocyanate groups and which also carry at least one hydrophilic group or a potentially hydrophilic group, thereby causing the water-dispersibility of the polyurethanes, at least some of the monomers (b3) in the hydrophilic group or potentially hydrophilic group are a carboxyl group or a potential carboxyl group.
• b4) optionally further polyvalent compounds with reactive groups which differ from the monomers (b1) to (b2) and which are alcoholic hydroxyl groups, primary or secondary amino groups or isocyanate groups and
• b5) optionally monohydric compounds which differ from the monomers (b1) to (b4) and have a reactive group which is an alcoholic hydroxyl group, a primary or secondary amino group or an isocyanate group.

7. Aqueous dispersions according to claim 5, wherein the phase (P. I) is essentially formed from a polyurethane (a), whose structural component (a3) carries sulfonate groups, and wherein the phase (P. II) is essentially formed from a poly urethane (b), its structural component (b3) carboxyl groups carries, some in the form of their ammonium or alkali salts available. 8. Aqueous dispersions according to claim 5, wherein the phase (P. II) is essentially formed from a polymer (c) which is derived from C ₁ - to C ₂₀ -alkyl (meth) acrylates and optionally acrylonitrile as monomers ( c1) and (meth) acrylic acid as monomer (c2). 9. Use of the dispersions according to claims 1 to 8 as Impregnating agent, coating agent or adhesive. 10. Objects made of wood, metal, textile, leather or plastic, which with an aqueous dispersion according to claims 1 to 8 are glued, impregnated or coated.