DE102008000270A1 - Producing aqueous dispersions of polyadducts comprises reacting starting compounds in a high-boiling water-miscible solvent, dispersing the resulting solution in water and removing the solvent - Google Patents

Abstract

Producing aqueous dispersions of polyadducts from mutually reactive starting compounds comprises reacting the starting compounds in a water-miscible solvent with a boiling point above 100[deg] C, dispersing the resulting solution in water and removing the solvent to leave less than 0.5 wt.% in the dispersion. An independent claim is also included for dispersions produced as above.

Description

• I) die Ausgangsverbindungen werden in einem mit Wasser mischbaren Lösemittel mit einem Siedepunkt größer 100°C bei 1 bar (im Nachfolgenden hochsiedendes Lösemittel genannt) oder in einem Lösmittelgemisch, welches ein hochsiedendes Lösemittel enthält, zum Polyaddukt oder einer Vorstufe davon umgesetzt,
• II) die erhaltene Lösung wird in Wasser dispergiert wird und gegebenenfalls werden weitere Umsetzungen zum Polyaddukt durchgeführt und
• III) das hochsiedende Lösemittel wird zu einem beliebigen Zeitpunkt nach der Dispergierung in Wasser bis auf einen Gehalt kleiner 0,5 Gew.-%, bezogen auf die Dispersion des Polyaddukts, entfernt.

The present invention relates to a process for the preparation of aqueous dispersions of polyadducts from mutually reactive starting compounds, which comprises the following process steps:

• I) the starting compounds are reacted in a water-miscible solvent having a boiling point greater than 100 ° C. at 1 bar (hereinafter referred to as high-boiling solvent) or in a solvent mixture which contains a high-boiling solvent to give the polyadduct or a precursor thereof,
• II) the resulting solution is dispersed in water and optionally further reactions to the polyadduct are carried out and
• III) the high-boiling solvent is removed at any time after the dispersion in water to a content of less than 0.5 wt .-%, based on the dispersion of the polyadduct removed.

to Preparation of aqueous polyurethane dispersions Starting compounds (polyisocyanates and polyalcohols) usually first in an organic solvent with each other implemented. For the organic solvents used can it be z. For example, low-boiling solvents such as acetone or methyl ethyl ketone. In alternative methods, in Solvents with a boiling point above 100 ° C worked at 1 bar or it will be high and low boiling solvents used together.

The product obtained is dispersed in water, if necessary then more conversions, z. B. for chain extension or networking. From the dispersion can low-boiling solvents (boiling point at 1 bar less 100 ° C) are easily separated by distillation. Solvents with a boiling point at 1 bar above 100 ° C remain in the dispersion and later in filming the dispersion removed along with the water.

in principle it is desired that the aqueous dispersions already completely free of organic solvents are.

Out the aqueous polyurethane dispersions are dried Polyurethane films produced. Depending on the purpose and composition the polyurethane is z. As to adhesive films or Protective coatings. The polyurethane films are intended for the purpose of use as good as possible application Have properties. Also is for many applications of Meaning that the application properties soon are fully formed after the preparation of the polyurethane film.

Methods for removing ionic constituents from water are described, for. In EP-A 571 069 and WO 2005/047342 described. In M. C Wilkinson et. al., The British Polymer Journal, 13, 82 ff. (1981) and SM Ahmed et. al., J. Coll. Interf. Sci., 73, 388 ff. (1980) Detailed information on the microfiltration (diafiltration) of polymer dispersions can be found.

task Therefore, the present invention was a process for production of polyadduct dispersions, in particular polyurethane dispersions, which are as solvent-free as possible and in the later use good performance properties to have.

Accordingly, became Found the initially defined method. Were also found Polyadduct dispersions obtained by this method are and the use of these polyadduct dispersions.

To the polyadduct

Under The term polyadduct is used to describe polymers formed by adduct formation be formed by reactive starting compounds, without water or other compounds splitting off.

polyadducts are z. As polyureas, which by reaction of polyisocyanates arise with amino compounds, or polyurethanes, which by Implementation of polyisocyanates and polyalcohols arise.

Under Polyurethane is to be understood below as a polyadduct, which is at least 60% by weight, in particular at least 80% by weight consists of polyisocyanates and polyalcohols.

Prefers If the polyadducts are polyurethanes.

• a) Diisocyanaten,
• b) Diolen, von denen
• b₁₎ 10 bis 100 mol-%, bezogen auf die Gesamtmenge der Diole (b), ein Molekulargewicht von 500 bis 5000 aufweisen, und
• b₂₎ 0 bis 90 mol-%, bezogen auf die Gesamtmenge der Diole (b), ein Molekulargewicht von 60 bis 500 g/mol aufweisen,
• c) von den Monomeren (a) und (b) verschiedene Monomere mit wenigstens einer Isocyanatgruppe oder wenigstens einer gegenüber Isocyanatgruppen reaktiven Gruppe, die darüber hinaus wenigstens eine hydrophile Gruppe oder eine potentiell hydrophile Gruppe tragen, wodurch die Wasserdispergierbarkeit der Polyurethane bewirkt wird,
• d) gegebenenfalls weiteren von den Monomeren (a) bis (c) verschiedenen mehrwertigen Verbindungen mit reaktiven Gruppen, bei denen es sich um alkoholische Hydroxylgruppen, primäre oder sekundäre Aminogruppen oder Isocyanatgruppen handelt und
• e) gegebenenfalls von den Monomeren (a) bis (d) verschiedenen einwertigen Verbindungen mit einer reaktiven Gruppe, bei der es sich um eine alkoholische Hydroxylgruppe, eine primäre oder sekundäre Aminogruppe oder eine Isocyanatgruppe handelt.

Suitable polyurethanes are preferably composed of the following starting compounds (also referred to below as monomers):

• a) diisocyanates,
• b) Diols, of which
• b ₁₎ 10 to 100 mol%, based on the total amount of diols (b), have a molecular weight of 500 to 5000, and
• b ₂₎ 0 to 90 mol%, based on the total amount of diols (b), have a molecular weight of 60 to 500 g / mol,
• c) monomers other than monomers (a) and (b) having at least one isocyanate group or at least one isocyanate group-reactive group further having at least one hydrophilic group or a potentially hydrophilic group, thereby effecting water-dispersibility of the polyurethanes;
• d) optionally other polyfunctional compounds other than the monomers (a) to (c), having reactive groups which are alcoholic hydroxyl groups, primary or secondary amino groups or isocyanate groups, and
• e) optionally monovalent compounds other than the monomers (a) to (d), having a reactive group which is an alcoholic hydroxyl group, a primary or secondary amino group or an isocyanate group.

Particular mention may be made as monomers (a) diisocyanates X (NCO) ₂ , wherein 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 carbon atoms. Examples of such diisocyanates are tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 1,4-diisocyanatocyclohexane, 1-isocyanato-3,5,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI), 2,2-bis (4-isocyanatocyclohexyl) propane, trimethylhexane diisocyanate, 1,4-diisocyanatobenzene, 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, 4,4'-diisocyanato-diphenylmethane, 2,4'-diisocyanato-diphenylmethane, p-xylylene diisocyanate, tetramethylxylylene diisocyanate (TMXDI), the isomers of the bis- (4-isocyanatocyclohexyl) methane (HMDI) as the trans / trans, the cis / cis and the cis / trans isomers and mixtures consisting of these compounds.

such Diisocyanates are commercially available.

When Mixtures of these isocyanates are especially the mixtures of the respective Structured isomers of diisocyanatotoluene and diisocyanato-diphenylmethane Of importance, in particular, the mixture of 80 mol% 2,4-diisocyanatotoluene and 20 mol% of 2,6-diisocyanatotoluene. Furthermore, the Mixtures of aromatic isocyanates such as 2,4 diisocyanatotoluene and / or 2,6-diisocyanatotoluene with aliphatic or cycloaliphatic Isocyanates such as hexamethylene diisocyanate or IPDI particularly advantageous, wherein the preferred mixing ratio of the aliphatic to aromatic isocyanates is 4: 1 to 1: 4.

To the Construction of the polyurethanes can be considered as compounds except the above also use isocyanates, in addition to the free Isocyanate groups further capped isocyanate groups, eg. B. wear uretdione groups.

in the With regard to good film formation and elasticity come as Diols (b) predominantly higher molecular weight diols (b1) into consideration, which has a molecular weight of about 500 to 5,000, preferably from about 1000 to 3000 g / mol.

The diols (b1) are in particular polyester polyols, the z. B. off Ullmanns Encyklopadie der technischen Chemie, 4th Edition, Volume 19, pp. 62 to 65 are known. Preference is given to using polyesterpolyols which are obtained by reacting dihydric alcohols with dibasic carboxylic acids. Instead of the free polycarboxylic acids, it is also possible to use the corresponding polycarboxylic acid anhydrides or corresponding polycarboxylic acid esters of lower alcohols or mixtures thereof to prepare the polyesterpolyols. The polycarboxylic acids may be aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic and optionally, for. B. by halogen atoms, substituted and / or unsaturated. Examples of these are: suberic acid, azelaic acid, phthalic acid, isophthalic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrachlorophthalic anhydride, endomethylenetetrahydrophthalic anhydride, glutaric anhydride, maleic acid, maleic anhydride, fumaric acid, dimer fatty acids. Preferred are dicarboxylic acids of the general For mel HOOC- (CH ₂ ) _y -COOH, where y is a number from 1 to 20, preferably an even number from 2 to 20, z. Succinic acid, adipic acid, sebacic acid and dodecanedicarboxylic acid.

As polyhydric alcohols come z. As 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 (hydroxymethyl) cyclohexanes such as 1,4-bis (hydroxymethyl) cyclohexane, 2-methylpropane-1,3-diol, methylpentanediols, furthermore diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, Dibutylene glycol and polybutylene glycols into consideration. Alcohols of the general formula HO- (CH ₂ ) _x -OH, where x is a number from 1 to 20, preferably an even number from 2 to 20, are preferred. Examples of these are ethylene glycol, butane-1,4-diol, hexane-1,6-diol, octane-1,8-diol and dodecane-1,12-diol. Further preferred is neopentyl glycol.

Further also come polycarbonate diols, as z. B. by implementation of Phosgene with an excess of as building components obtained for the polyester polyols mentioned low molecular weight alcohols can be considered.

Also suitable are lactone-based polyesterdiols, which are homopolymers or copolymers of lactones, preferably terminal hydroxyl-containing addition products of lactones 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 denoted by a C ₁ - to C _4- alkyl radical may be substituted. Examples are e-caprolactone, β-propiolactone, g-butyrolactone and / or methyl-e-caprolactone and mixtures thereof. Suitable starter components are for. As the above-mentioned as a structural component for the polyester polyols low molecular weight dihydric alcohols. The corresponding polymers of e-caprolactone are particularly preferred. Lower polyester diols or polyether diols can also be used as starters for the preparation of the lactone polymers. Instead of the polymers of lactones, it is also possible to use the corresponding, chemically equivalent polycondensates of the hydroxycarboxylic acids corresponding to the lactones.

In addition, suitable monomers (b1) are polyether diols. They are in particular by polymerization of ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide or epichlorohydrin with itself, z. B. in the presence of BF ₃ or by addition of these compounds, optionally in admixture or in succession, to starting components with reactive hydrogen atoms, such as alcohols or amines, for. For example, water, ethylene glycol, propane-1,2-diol, propane-1,3-diol, 1,2-bis (4-hydroxydiphenyl) propane or aniline available. Particularly preferred is polytetrahydrofuran having a molecular weight of 240 to 5000, and especially 500 to 4500.

Also suitable are polyhydroxyolefins, preferably those having 2 terminal hydroxyl groups, for. B. a, -w-dihydroxypolybutadiene, a, -w-Dihydroxypolymethacrylester or a, -w-Dihydroxypolyacrylester as monomers (c1). Such compounds are for example from the EP-A 0622378 known. Further suitable polyols are polyacetals, polysiloxanes and alkyd resins.

The Polyols can also be used as mixtures in proportion 0.1: 1 to 1: 9 are used.

The Hardness and the modulus of elasticity of the polyurethanes can be raised when as diols (b) next to the diols (b1) still low molecular weight diols (b2) with a molecular weight from about 60 to 500, preferably from 62 to 200 g / mol become.

When Monomers (b2) are mainly the building components of the the production of polyester polyols called short-chain alkanediols used, wherein the unbranched diols having 2 to 12 carbon atoms and an even number of C atoms and pentane-1,5-diol and Neopentyl glycol are preferred.

Prefers is the proportion of the diols (b1), based on the total amount the diols (b) 10 to 100 mol% and the proportion of the monomers (b2), based on the total amount of diols (b) 0 to 90 mol%. Especially the ratio of the diols (b1) is preferably to the monomers (b2) 0.1: 1 to 5: 1, more preferably 0.2: 1 to 2: 1.

In order to achieve the water-dispersibility of the polyurethanes, the polyurethanes, in addition to the components (a), (b) and, if appropriate, (d) are monomers (c) which are different from components (a), (b) and (d) and which are at least one Isocyanate group or at least one isocyanate-reactive group and moreover at least one hydrophilic group or a group which can be transformed into a hydro phile group, carry, built. In the following text, the term "hydrophilic groups or potentially hydrophilic groups" is abbreviated to "(potentially) hydrophilic groups". The (potentially) hydrophilic groups react much more slowly with isocyanates than the functional groups of the monomers which serve to build up the polymer main chain.

Of the Proportion of components with (potentially) hydrophilic groups on the Total amount of components (a), (b), (c), (d) and (e) is generally such that the molar amount of the (potentially) hydrophilic groups, based on the amount by weight of all monomers (a) to (e), 30 to 1000, preferably 50 to 500 and particularly preferably 80 to 300 mmol / kg is.

at the (potentially) hydrophilic groups may be nonionic or preferably (ionic) hydrophilic groups.

When Nonionic hydrophilic groups are especially polyethylene glycol ethers preferably from 5 to 100, preferably from 10 to 80 ethylene oxide repeating units, into consideration. The content of polyethylene oxide units is in general 0 to 10, preferably 0 to 6 wt .-%, based on the Weight of all monomers (a) to (e).

Preferred monomers having nonionic hydrophilic groups are polyethylene oxide diols, polyethylene oxide monools and the reaction products of a polyethylene glycol and a diisocyanate which carry a terminally etherified polyethylene glycol radical. Such diisocyanates and processes for their preparation are in the patents US-A 3,905,929 and US-A 3,920,598 specified.

Ionian hydrophilic groups are especially anionic groups such as the sulfonate, the carboxylate and phosphate groups in the form of their alkali metal or ammonium salts and cationic groups such as ammonium groups, in particular protonated tertiary amino groups or quaternary Ammonium groups.

Potentially ionic hydrophilic groups are especially those that are characterized by simple neutralization, hydrolysis or quaternization reactions into the above-mentioned ionic hydrophilic groups leave, so z. As carboxylic acid groups or tertiary Amino groups.

(Potentially) ionic monomers (c) are e.g. In Ullmann's Encyclopedia of Industrial Chemistry, 4th Edition, Volume 19, pp. 311-313 and for example in the DE-A 14 95 745 described in detail.

When (potential) cationic monomers (c) are especially monomers with tertiary amino groups of particular practical importance, for example: tris- (hydroxyalkyl) -amines, N, N'-bis (hydroxyalkyl) -alkylamines, N-hydroxyalkyl-dialkylamines, tris (aminoalkyl) -amines, N, N'-bis (aminoalkyl) -alkylamines, N-aminoalkyl-dialkylamines, wherein the alkyl radicals and alkanediyl units of these tertiary amines independently 1 to 6 carbon atoms. Furthermore come tertiary Nitrogen-containing polyether having preferably two terminal Hydroxyl groups, as z. By alkoxylation of two amine nitrogens bound hydrogen atoms containing amines, z. Methylamine, Aniline or N, N'-dimethylhydrazine, in per se Way in consideration. Such polyethers generally have a lying between 500 and 6000 g / mol Mol. Weight on.

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

in welcher R¹ und R² für eine C₁- bis C₄-Alkandiyl-Einheit und R³ für eine C₁- bis C₄-Alkyl-Einheit steht und vor allem Dimethylolpropionsäure (DMPA) bevorzugt.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. Preference is given to dihydroxyalkylcarboxylic acids, especially having 3 to 10 carbon atoms, as they are also in the US-A 3 412 054 are described. In particular, compounds of the general formula (c ₁ )

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 before dimethylolpropionic acid (DMPA).

Farther Suitable dihydroxysulfonic acids and dihydroxyphosphonic acids are suitable such as 2,3-dihydroxypropanephosphonic acid.

Otherwise suitable are dihydroxyl compounds having a molecular weight above 500 to 10,000 g / mol with at least 2 carboxylate groups, which from the DE-A 39 11 827 are known. They are obtainable by reacting dihydroxyl compounds with tetracarboxylic dianhydrides such as pyromellitic dianhydride or cyclopentanetetracarboxylic dianhydride in a molar ratio of 2: 1 to 1.05: 1 in a polyaddition reaction. Particularly suitable dihydroxyl compounds are the monomers (b2) listed as chain extenders and also the diols (b1).

As monomers (c) with isocyanate-reactive amino groups are aminocarboxylic acids such as lysine, β-alanine or in the DE-A 20 34 479 mentioned adducts of aliphatic diprimary diamines to a, β-unsaturated carboxylic or sulfonic acids into consideration.

Such compounds obey, for example, the formula (c ₂ ) H ₂ NR ⁴ -NH-R ⁵ -X (c2) in the
- R ⁴ and R ^{5 are} independently a C ₁ - to C ₆ alkanediyl moiety, preferably ethylene
and X is COOH or SO ₃ H.

Particularly preferred compounds of the formula (c ₂ ) are N- (2-aminoethyl) -2-aminoethanecarboxylic acid and N- (2-aminoethyl) -2-aminoethanesulfonic acid or the corresponding alkali metal salts, Na being particularly preferred as the counterion.

Also particularly preferred are the adducts of the abovementioned aliphatic diprimary diamines with 2-acrylamido-2-methylpropanesulfonic acid, as described, for example, in US Pat. B. in the DE Patent 19 54 090 are described.

Provided Monomers can be used with potentially ionic groups their transfer into the ionic form before, during, however, preferably after the isocyanate polyaddition, since the ionic monomers are often in the reaction mixture difficult to solve. Particularly preferably, the sulfonate or carboxylate groups in the form of their salts with an alkali metal ion or an ammonium ion as Ge genion before.

The Monomers (d) other than the monomers (a) to (c) and which are optionally also constituents of the polyurethane, generally serve for crosslinking or chain extension. It are generally more than dihydric non-phenolic alcohols, Amines with 2 or more primary and / or secondary Amino groups and compounds in addition to one or more alcoholic Hydroxyl groups one or more primary and / or secondary Wear amino groups.

alcohols with a value higher than 2, which is used for setting can serve a certain degree of branching or cross-linking, are z. B. trimethylolpropane, glycerol or sugar.

Further Monoalcohols come into consideration, in addition to the hydroxyl group a carry further isocyanate-reactive group 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 are mainly used when the chain extension or crosslinking in the presence of water, since amines usually faster than alcohols or water with isocyanates react. This is often required when watery Dispersions of crosslinked polyurethanes or polyurethanes with high molecular weight are desired. In such cases one proceeds in such a way that prepolymers with isocyanate groups prepared, this dispersed rapidly in water and then by adding compounds with more than isocyanates chain-extended or crosslinked reactive amino groups.

Suitable amines for this purpose are generally polyfunctional amines of the molecular weight range of From 32 to 500 g / mol, preferably from 60 to 300 g / mol, containing at least two amino groups selected from the group of primary and secondary amino groups. Examples of these are diamines such as diaminoethane, diaminopropanes, diaminobutanes, diaminohexanes, piperazine, 2,5-dimethylpiperazine, amino-3-aminomethyl-3,5,5-trimethyl-cyclohexane (isophoronediamine, IPDA), 4,4'-diaminodicyclohexylmethane, 1 , 4-diaminocyclohexane, aminoethylethanolamine, hydrazine, hydrazine hydrate or triamines such as diethylenetriamine or 1,8-diamino-4-aminomethyloctane.

The amines may also be in blocked form, for. In the form of the corresponding ketimines (see eg. CA-A 1 129 128 ), Ketazines (cf., for example, the US-A 4,269,748 ) or amine salts (s. US-A 4,292,226 ) are used. Oxazolidines, as used for example in the US-A 4,192,937 are used represent blocked polyamines, which can be used for the preparation of polyurethanes according to the invention for chain extension of the prepolymers. When using such capped polyamines they are generally mixed with the prepolymers in the absence of water and this mixture is then mixed with the dispersion water or a part of the dispersion water, so that the corresponding polyamines are hydrolytically released.

Prefers For example, mixtures of di- and triamines are used, more preferred Mixtures of isophorone diamine (IPDA) and diethylenetriamine (DETA).

The Polyurethanes preferably contain 1 to 30, more preferably 4 to 25 mol%, based on the total amount of components (b) and (d) a polyamine having at least 2 versus isocyanates reactive amino groups as monomers (d).

alcohols with a value higher than 2, which is used for setting can serve a certain degree of branching or cross-linking, are z. B. trimethylolpropane, glycerol or sugar.

For the same purpose may also be higher as monomers (d) be used as divalent isocyanates. commercial Compounds are for example the isocyanurate or the biuret hexamethylene diisocyanate.

monomers (e), which are optionally used, are monoisocyanates, Monoalcohols and monoprimary and secondary amines. In general, their proportion is at most 10 mol%, based on the total molar amount of monomers. These monofunctional compounds usually carry other functional groups such as olefinic Groups or carbonyl groups and are for introduction of functional groups in the polyurethane, which means the dispersion or the crosslinking or further polymer-analogous reaction of the polyurethane enable. Suitable monomers for this purpose such as isopropenyl-a, a-dimethylbenzyl isocyanate (TMI) and esters of Acrylic or methacrylic acid such as hydroxyethyl acrylate or Hydroxyethyl methacrylate.

On The field of polyurethane chemistry is well known as the Molecular weight of the polyurethanes by choosing the proportions of each other reactive monomers and the arithmetic mean of the number of adjusted reactive functional groups per molecule can be.

• A) der Molmenge an Isocyanatgruppen und
• B) der Summe aus der Molmenge der funktionellen Gruppen, die mit Isocyanaten in einer Additionsreaktion reagieren können

Normally, the components (a) to (e) 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 functional groups which can react with isocyanates in 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. Most preferably, the ratio A: B as close as possible to 1: 1.

The used monomers (a) to (e) usually carry on average 1.5 to 2.5, preferably 1.9 to 2.1, more preferably 2.0 isocyanate groups or functional groups that react with isocyanates in an addition reaction can react.

To the manufacturing process

Process step I)

The Reaction of the starting compounds of the polyadducts or of the polyurethane, is according to the invention in a water-miscible, preferably infinitely miscible solvent with a Boiling point greater than 100 ° C at 1 bar (short high-boiling solvent) or in a solvent mixture, which contains a high-boiling solvent, performed.

in the In the case of the solvent mixtures, preference is given to those which at least 5 wt .-%, in particular at least 10 wt .-%, but also at least 25 wt .-% or at least 50 wt .-% from the high-boiling Solvents exist.

In In a particular embodiment, the reaction is in a solvent mixture containing more than 75% by weight consists of the high-boiling solvent or only in the high boiling solvent (100 wt .-%) made.

When high-boiling solvents include N-methylpyrrolidone (NMP), Dimethylformamide, dimethylacetamide, ethers of ethylene and propylene glycol, in particular dipropylene glycol methyl ether or alkylpyrrolidones in Consideration.

at the mixtures of high-boiling solvents with others Solvents (boiling point below 100 ° C, at 1 bar), are in particular mixtures with acetone or methyl ketone.

Especially The reaction of the starting compounds in NMP is preferably carried out or mixtures of NMP with other solvents, in particular with acetone.

Of the Solvent content is preferably 5 to 95 Wt .-%, particularly preferably 20 to 95 wt .-% based on the total Reaction mixture, which corresponds to a content of starting compounds, or after the reaction, a content of the polyadduct or a Prepolymers thereof of 5 to 95 wt .-% and 5 to 80 wt .-%.

in the Process step I) can all desired starting compounds a) to e) are converted to the polyurethane.

The Polyaddition to produce the polyurethane is preferably carried out at reaction temperatures of 20 to 180 ° C, preferably 50 up to 150 ° C under normal pressure or under autogenous pressure.

The required reaction times are generally from 1 to 20 Hours, in particular in the range of 1.5 to 10 hours. It is in the field of polyurethane chemistry known as the reaction time through a variety of parameters such as temperature, concentration of monomers, Reactivity of the monomers is influenced.

When Polymerization apparatuses come in particular stirred tank into consideration.

In an alternative manufacturing method (also prepolymer mixing method called) the implementation is carried out in two stages. at This method is in step I) first a prepolymer prepared carrying isocyanate groups. The components are hereby preferably chosen so that the definition Ratio A: B greater than 1.0 to 3, preferably 1.05 to 2.0. The prepolymer becomes first dispersed in water and then optionally by Reaction of the isocyanate groups with amines that are more than 2 opposite Isocyanates carry reactive amino groups, crosslinked or with amines, which carry 2 isocyanate-reactive amino groups, chain extended. A chain extension finds even if no amine is added. In this case will be Isocyanate groups hydrolyzed to amino groups, with the remaining Isocyanate groups of the prepolymers with chain extension react.

Process step II

The in I) is dispersed in water. water can be stirred into the solution, it can but also presented water and the solution stirred become.

you receives a dispersion of the polyadduct, or polyurethane, or a prepolymer thereof in a mixture of water and the solvent or solvent mixture.

in the If a polyurethane prepolymer is used, the reaction takes place the remaining isocyanate groups preferably as described above.

Low boiling solvents, if used, are from the Dispersion preferably by distillation at reduced pressure away.

Process step III

To dispersing in water also becomes the high-boiling solvent largely removed. This can be done at any time after dispersion happen.

in the Case of the prepolymer is the removal of the high-boiling Solvent preferably after the complete Reaction to the polyadduct, or polyurethane.

at Co-use of low-boiling solvents is preferred first remove the low-boiling solvent.

In front the removal of the high-boiling solvent the content of the high-boiling solvent in general at least 0.5, in particular at least 1 or else at least 2 Wt .-%, but also z. B. at least 10 wt .-% based on the total Dispersion of polyadduct, water and solvent, the content is generally not greater than 50% by weight or as 40% by weight, based on the total dispersion of polyadduct, Water and solvents.

The removal of the high-boiling solvent is preferably carried out by the method of microfiltration, also called diafiltration or ultrafiltration. This process is described for removing ionic constituents from water, also from polymer dispersions, e.g. In M. C Wilkinson et. al., The British Polymer Journal, 13, 82 ff. (1981) and SM Ahmed et. al., J. Coll. Interf. Sci., 73, 388 ff. (1980) ,

at The microfiltration will pressurize water through the water Polymer dispersion passed. An overpressure of 0.1 to 1 bar is generally sufficient. The microfiltration may be at Room temperature to be performed. After passing through a membrane which is impermeable to the dispersion particles is the water containing the constituents to be removed, removed (eluate). Water is passed through the dispersion as long as until the desired degree of purity of the retained Polymer dispersion (retentate) is reached. Ultimately, the Method on the exchange of dispersion water with its dissolved Ingredients to the freshly supplied water (serum exchange).

The finally obtained according to process step III aqueous Dispersions of the polyadducts, in particular of the polyurethanes contain less than 0.5% by weight, especially less than 0.2% by weight, especially preferably less than 0.1 or less than 0.05 wt .-%, based on the entire dispersion, the high-boiling solvent.

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

The Polyadduct dispersions, in particular polyurethane dispersions are suitable as binders for adhesives, coating compositions, Paints or impregnating agents.

The Adhesives, coating agents, lacquers or impregnating agents may consist solely of the polyurethane dispersion or contain further ingredients.

she may be commercial auxiliaries and additives such as propellants, defoamers, emulsifiers, thickeners and thixotropic agents, colorants such as dyes and pigments, containing tackifying resins (tackifiers).

The dispersions of the invention are suitable for coating articles of metal, plastic, paper, textile, leather or wood, by applying them by the commonly used methods, ie, for. B. by spraying or knife coating in the form of a film on these objects and the dispersion dries.

The aqueous dispersions are characterized by their freedom from solvents and also by improved performance properties. Movies from the polymer dispersions dry very quickly and have a lot quickly the desired application properties, z. B. hardness and elasticity. Surprisingly the properties are permanently better after drying is complete and have a level without carrying out the invention Procedure is not reached.

example

A commercial polyurethane dispersion (Astacin Finish PF ^® from BASF AG) with a polymer content of 37 wt .-% and a content of 4.0 wt .-% NMP is diluted with water to 19.4 wt .-% solids content diluted.

250 g of this dispersion are in the diafiltration cell (Amicon stirred cell 8400, Fa. Amicon) and at 21 ° C is with stirring (500 rpm) and with slight overpressure (0.2 bar) demineralized water passed through the dispersion. The Eluate is after passing through the polycarbonate sieve filter membrane (Nucleopore, 0.1 μm, D = 76 mm) at the bottom of the apparatus collected and the NMP content determined. The total amount of eluate is 1240 g for 30 hours. The NMP content of the retentate (diafiltered PU dispersion) is less than 0.05% by weight, determined by GC analysis.

From of the diafiltered dispersion were on a glass plate films poured with a dry thickness of 1.0 mm; also from the starting dispersion.

17 Hours after pouring the films had dried so far that they could be pulled off the glass plate. From the movies strips measuring 15x40 mm were cut out. Each six strips were placed on top of each other and on a device of type BE 62 from Bareiss Prüfgerätebau GmbH the Shore A hardness is determined according to ASTM D 2240. Every measurement returns the average of five individual measurements.

The example was repeated. (Examples 1 and 2) Table: ShoreA hardnesses measured at defined time intervals Time after pouring the films in hours Product with NMP content of 4% by weight (Astacin Finish PF for comparison) example 1 Example 2 17.5 51 87.8 84.4 18.5 51 86.8 78.8 19.5 60 85 77.6 20.5 65.2 87 81.6 21.5 63.6 88.6 80.6 40.5 69.2 82.6 79 41.5 69.2 86.2 81.6 42.5 70.2 85 83.2 43.5 70.2 86 77.2 44.5 71.4 88.8 78 45.5 66.6 85 81 64.5 64.4 89.6 88 65.5 68.2 89.8 85.8 71.5 69.6 89.4 87.8 136.5 67.4 90.2 88.2 140.5 68.8 88.6 89.2

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - EP 571069 A [0006]
• WO 2005/047342 [0006]
• - EP 0622378 A [0024]
• - US 3905929 A [0033]
• - US 3920598 A [0033]
• - DE 1495745 A [0036]
• - US 3412054 A [0039]
• - DE 3911827 A [0041]
• - DE 2034479 [0042]
• - DE 1954090 [0045]
• - CA 1129128 A [0052]
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Cited non-patent literature

• In M. C Wilkinson et. al., The British Polymer Journal, 13, 82 et seq. (1981) [0006]
• - SM Ahmed et. al., J. Coll. Interf. Sci., 73, 388 ff. (1980) [0006]
• - Ullmanns Encyklopadie der technischen Chemie, 4th Edition, Volume 19, pp. 62 to 65 [0019]
• Ullmanns Encyklopadie der technischen Chemie, 4th Edition, Volume 19, pp. 311-313 [0036]
• - M. C Wilkinson et. al., The British Polymer Journal, 13, 82 et seq. (1981) [0082]
• - SM Ahmed et. al., J. Coll. Interf. Sci., 73, 388 et seq. (1980) [0082]

Claims (7)

Process for the preparation of aqueous dispersions of polyadducts from mutually reactive starting compounds, characterized in that I) the starting compounds in a water-miscible solvent having a boiling point greater than 100 ° C at 1 bar (hereinafter referred to as high-boiling solvent) or in a solvent mixture, which II) the resulting solution is dispersed in water and optionally further reactions to the polyadduct are carried out and III) the high-boiling solvent at any time after dispersion in water to a content less than 0.5 wt .-%, based on the dispersion of the polyadduct is removed. Process according to claim 1, characterized in that they are polyadducts which are at least 60% by weight of polyisocyanates and polyalcohols (starting compounds) consist (in the following called polyurethanes). A method according to claim 1 or 2, characterized in that it is the high-boiling solvent in process step a) is N-methylpyrrolidone. Method according to one of the claims 1 or 2, characterized in that the high-boiling solvent is removed by ultrafiltration. Method according to one of the claims 1 or 2, characterized in that the high-boiling solvent to a residual content less than 0.2 wt .-%, based on the dispersion of the polyadduct, is removed. Aqueous dispersions of polyadducts, obtainable by a method according to of claims 1 to 5. Use of the aqueous dispersions according to claim 6 as a binder in adhesives, coating compositions, paints or Impregnation agents.