DE2344135C2 - Process for the continuous production of aqueous polyurethane dispersions - Google Patents

Description

The term "polyurethane dispersions" includes both aqueous dispersions and suspensions of to understand pure polyurethanes as well as polyurethane ureas. Such polyurethane urea dispersions are described, for example, in Applied Chem. 82 (1970), p. 53 and in Angew. macromol. Chem. 26 (1972), p.85.

The production of disperse polyurethanes and polyurethane ureas is done according to an older one Proposal by the applicant (see. DE-OS 23 11 635) so that one an NCO prepolymer, a chain extender and a liquid aqueous phase in a Introduces zone of high turbulence and allows the polyaddition and formation of a disperse phase to take place there A zone of high turbulence is understood to be a space through which - with intensive mixing - at least 300 parts by volume of liquid per part by volume of the

Room and per hour.

The conventional device for generating a zone of high turbulence consists in a stirred tank with Stirrers and possibly baffles. For the discontinuous production of dispersions and suspensions

ίο is mainly with such mixing units worked

Mixing reactors are more suitable, as they are in the DE-OS 22 60 870 or gyroscopic homogenizers as described in DE-OS 2311635. These Machines have the advantage that they enable continuous production.

However, all previously used Vc. 'Directions for the production of dispersions and suspensions - mainly based on polyurethane and polyurethane hammer Substance base - has the disadvantage that for the Mixing of the starting components mechanically moved units are used. This remains their throughput to 300 to 10,000 parts by volume of liquid per part by volume of the room and per hour limited and their mixing power limited to the range of 10- 'to 25 watts / cm ³

It has now been found, surprisingly, that polyurethanes and polyurethane ureas are used as Produce dispersion or suspension continuously can if one is a liquid or in an organic Solvent-dissolved prepolymer having terminal isocyanate groups, which is produced by reaction of Di- or polyisocyanates with compounds having at least two active hydrogen atoms with one Molecular weight of 400 to 10,000 has been obtained by countercurrent injection with water, optionally with the use of emulsifiers or other suitable auxiliaries, mixed and optionally before, during or after the mixing

Chain extender adds.

The fact that liquids can be intensively mixed with one another by countercurrent injection, is known. The mixing of liquid components is based on the principle of countercurrent injection With the help of countercurrent injection machines, such as those used in the manufacture of polyurethane foams. As from the literature, e.g. B. in high Polymers, Vol. XVI, Polyurethanes, Chemistry and Technology, written by Saunders-Frisch, Intenscien ce Publishers, New York, London, Volume II, 1964, p 195, and from specialist literature, e.g. B. Leaflet Order No .: DU 5726 from 1.8.1965, Bayer Leverkusen, "Moltropren atomizing machines type" HK ", or" Mobay Equipment Report "No. 3, Mobay Chemical Company, Penn Lincoln Parkway West, Pittsburgh, Pennsylvania, and in particular also from "Kunststoff-Handbuch", Volume VII, "Polyurethane", Carl-Hanser-Verlag Munich (1966), pages 149 ff., Can be seen such countercurrent injection machines have long been: be known state of the art.

The advantage of using such countercurrent injection machines in the production of polyurethane dispersions is, in particular, that the per part of the volume of the room and per unit of time mixed volume of liquid is significantly larger than with the previously used mixing units. For example, a machine mixes the Type HK 15, which is described in more detail in Example 1,

with a mixing chamber volume of 0.5 cm * and a discharge of 180 kg / hour 360,000 parts by volume of the room and per hour, assuming 1 g / cm ³ as the mean density of the discharged material. A machine of the HK100 type with a mixing chamber volume of 1 cm ³ and an output of 20 kg per minute or a machine of the type HK1000 with a mixing chamber volume of 5 cm ³ and an output of 100 kg per minute mix in the same way 1 200 000 Volumenteiie per Volumenteiie of the room and per hour. -

While the mixing performance in the intensively stirred stirred vessel generally 10-t to 10- ³ watts / cm ³ and the specific mixing power of Kreiselhomogenisiermaschinen 25 watts / cm does not exceed ^3, z achieved. B. a machine of the HK100 type with a mixing chamber volume of 1 cm ³ and an output of 20 kg per unit, which is operated with 150 atmospheric pressure, a mixing power of about 5000 watts / cm ³ with 100% mixing. Even with a mixing efficiency of only 10%, the mixing power would still be approx. 500 watt / cm ³ .

The high mixing performance achieved using the countercurrent injection principle during mixing liquid components achieved with the help of HK machines surpasses all of the production methods so far processes used by dispersions and suspensions.

Another advantage is that the zone is higher Turbulence only an extremely small mixing space is used, which in contrast to the usual-. Mixing units are particularly easy to clean.

The fact is that only an extremely small mixing space is used as the zone of high turbulence which, in contrast to the usual mixing units, is particularly easy to clean

The fact that polyurethane dispersions can be produced in such countercurrent injection machines, is surprising in that so far such machines have not been used for the production of polymer dispersions in Water were used because difficulties such as coagulum formation and nozzle clogging were expected had to be when liquids with such different viscosities as described below The invention explained are used to be mixed with a high flow rate. In contrast it was surprisingly found that even with a viscosity ratio of the two liquids to be mixed of more than 1:20 and up to 1: 1500 perfect dispersion occurs without coagulum formation. With coagulum formation, in particular, also had to be expected, since it belongs to the known state of the art that polymer or plastic dispersions when exposed to high shear forces coagulate.

The present invention thus provides a process for the continuous production of aqueous polyurethane spursions by mixing one liquid or one containing terminal isocyanate groups dissolved in an organic solvent Prepolymers with at least two NCO groups in the molecule, which are produced by reacting di- or polyisocyanates with compounds with at least two active Hydrogen atoms with a molecular weight of 400 to 10,000 has been obtained with water and optionally with the addition of chain extenders with at least two isocyanate-reactive groups with a molecular weight weight from 18 to 400 before, during or after the mixing of the prepolymer with the aqueous phase or of only one isocyanate-reactive group and ionic centers send connections as well as possibly under Use of 0.01 to 40% by weight, based on the aqueous phase, of an emulsifier, laminate, ionic or hydrophilic polyurethane, characterized in that the mixing of the

IH gang components according to the countercurrent injection process, with at least one of the to mixing components are compressed to a pre-pressure of 20 to 500 atmospheres and through a nozzle in the Mixing chamber with the other component or components

is mixed.

The present invention also relates to the use of those produced by this process aqueous polyurethane dispersions for the production of polyurethane powders.

According to the invention, prepolymers containing terminal isocyanate groups and having at least 2 NCO groups per molecule. Reaction products of di- or polyisocyanates with compounds with at least two active hydrogen atoms with one Molecular weight from 4CG to 10,000 dies means that at least 2 moles of NCO groups must be present per mole of active hydrogen during the reaction. Such prepolymers are known for their production

jo treatment is generally used polyols of the appropriate molecular weight with excess di- or Polyisocyanates around.

The polyols have a molecular weight of from 400 to 10,000, preferably from 500 to 4000, and from 2 to 8

Hydroxyl groups, preferably 2 hydroxyl groups,

per molecule. Preference is given to using polyester

Polyethers, polythioethers, polyacetals, polycarbonates

and polyester amides of the type known per se.

Examples of suitable polyesters are implementation

products of polyhydric, preferably dihydric and optionally additionally trihydric alcohols with polyhydric, preferably dihydric Carboxylic acids. Instead of the free polycarboxylic acids, the corresponding polycarboxylic acid anhy dride or corresponding polycarboxylic acid esters of lower alcohols or mixtures thereof can be used to produce the polyesters. The polycarboxylic acids can be aliphatic, cycloaliphatic ^ aromatic and / or heterocyclic in nature and

so if necessary, e.g. B. substituted by halogen atoms and / or unsaturated. Examples are called: succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, Trimellitic acid, phthalic anhydride, tetrahydroph thalic anhydride, hexahydrophthalic anhydride, te- trachlorophthalic anhydride, endomethylenetetrahydrophthalic anhydride, glutaric anhydride, maleic acid, maleic anhydride, fumaric acid, dimers and trimeric fatty acids, such as oleic acid, optionally in Mixture with monomeric fatty acids, dimethyl terephthalate and bis-glycol terephthalate Als polyhydric alcohols come e.g. B. ethylene glycol, propylene glycol-1,2 and -1,3, butylene glycol-1,4 and -23, 1,6-kexanediol, 1,8-octanediol, neopentyl glycol, 1,4-bis- (hydroxymethyl) cyclohexane, 2-methyl-1,3-propanediol, Glycerol, trimethylolpropane, hexanetriol-1,2,6, butanetriol-1,2,4, trimethylolethane, pentaerythritol, quinitol, mannitol and sorbitol as well as methyl glycoside are possible.

The polyacetals are ζ. B. from glycols, such as Diethylene glycol, triethylene glycol, 4,4'-dioxyethyldiphenyldimethylmethane and hexanediol and formaldehyde preparable compounds in question. Also through Polymerization of cyclic acetals can be used to produce suitable polyacetals.

Polycarbonates containing hydroxyl groups are those of the type known per se. B. by reacting diols such as propanediol-13, butanediol-1,4 and / or hexanediol-1,6, diethylene glycol, triethylene glycol and tetraethylene glycol with diaryl carbonates, £. B. diphenyl carbonate, with dialkyl carbonates such as diethyl carbonate, or phosgene can be prepared.

The polyester amides and polyamides include, for. B. those of polyvalent saturated and unsaturated Carboxylic acids or their anhydrides and polyvalent saturated and unsaturated amino alcohols, Diamines, polyamines and their mixtures are obtained, mainly linear condensates.

Also already urethane or substance groups containing polyhydroxy compounds and optionally modified natural polyols, such as castor oil, Carbohydrates, and starches, are usable. Also adducts of alkylene oxides with phenol-formaldehyde resins or urea-formaldehyde resins are used as polyol components for prepolymers applicable. J

Representatives of these compounds to be used according to the invention are, for. B. in High Polymers, Vol. XVI, "Polyurethanes, Chemistry and Technology," written by Saunders-Frisch, Interscience Publishers, New York, London, Volume I, 1962, pages 32-42 and pages 44-54, and Volume II, 1964, pages 5-6 and 198 and 199, as well as in "Kunststoff-Handbuch", Volume VII, Vieweg-Höchtlen, Carl-Hanser-Verlag Munich, 1966, z. B. on on pages 45-71.

As di- or polyisocyanates for converting the polyols into prepolymers containing isocyanate groups come aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic polyisocyanates into consideration (cf. Ann. 562, pages 75-136), for example ethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,12-dodecane diisocyanate, Cyclobutane-13-diisocyanate, cyclohexane-13- and -1,4-diisocyanate and any mixtures of these isomers, l-isocyanato-S ^ -trimethyl-S-isocyanatomethylcyclohexane, 2,4- and 2,6-hexahydrotolylene diisocyanate as well as any mixtures of these isomers, hexahydro-13- and / or-1,4-phenylene diisocyanate, perhydro-2,4'- and / or -4,4'-diisocyanate, 13- and 1,4-phenylene diisocyanate, 2,4- and 2,6-toluylene diisocyanate and any mixtures of these isomeric, diphenylmethane-2,4'- and / or ^^ '- diisocyanate, naphthylene-1,5-diisocyanate, Tripheny] methane-4,4 ', 4 "-triisocyanate, polyphenylpolymethylene polyisocyanate, obtained by aniline-formaldehyde condensation and subsequent phosgenation according to GB-PS 8 74 430 and 8 48671, perchlorinated aryl polyisocyanates (cf. DE-AS 1157601), polyisocyanates containing carbodiimide groups (cf. DE-PS 10 92 007), diisocyanates according to US-PS 34 92 330, polyisocyanates containing allophanate groups (cf. GB-PS 9 94 890, BE-PS 7 61 626 and NL patent application 7102 524), isocyanurate groups containing Pclyisocyanate (see. DE-PS 10 22 789, 12 22 067 and 10 27 394 and DE-OS 19 29 034 and 20 04 048), polyisocyanates containing urethane groups (cf. BE-PS 7 52 261 and US-PS 33 94 164), acylated Polyisocyanates containing urea groups (see DE-PS 12 30 778), polyisocyanates containing biuret groups (see DE-PS 1101394, GB-PS 8 89 050 and FR-PS 7 017 514), polyisocyanates produced by telomerization reactions (see BE-PS 7 23 640), Polyisocyanates containing ester groups (cf. GB-PS 9 56 474 and 10 72 956, US-PS 35 67 763 and DE-PS 12 31688 and reaction products of the polyisocyanates mentioned with acetals (see DE-PS 10 72 385).

ίο The production of the isocyanate groups Prepolymers made from polyols and isocyanates are known (see R. Vieweg, A. Höchtlen, Kunststoff-Handbuch, Volume VII, Polyurethane, Carl-Hanser-Verlag Munich, 1966, pages 84-85).

It may be advantageous to use di- and polyisocyanates which have been cationically or anionically modified by suitable compounds. Such compounds suitable for ionic modification are described in DE-OS 1,770,068, for example. The ionic modification can also be carried out on the prepolymers (solutions) during or after their preparation. The production of ionically modified prepolymers can, for example, also be carried out in such a way that polyols containing tertiary nitrogen atoms, in particular polyhydroxyl polyethers, are used to produce the prepolymers, which before or after the reaction with the polyisocyanate is converted into compounds containing = N® = groups by a quaternizing agent . Ionic modified NCO prepolymers obtainable according to DE-PS 12 82 962 can also be used in the process according to the invention. In the process according to the invention, ionically modified NCO prepolymers can be used which have an ionic group content, in particular of = N® =, —COO ^e - or —SO ₃ ^e - of 2 to 200 milliequivalents per 100 g.

Also nonionically modified prepolymers, as they are for the production of polyurethane dispersions according to DE-OS 21 41 805, 21 41 807, 23 14 513 or 23 14 512 3 can be used according to the invention will. Mixtures of the propellants mentioned can also be used.

For the process according to the invention, prepolymers are preferably used whose viscosity is the processing temperature is below 2000 cP, preferably between 50 and 150OcP, since it is for a Processing in countercurrent injection machines are particularly suitable. It therefore makes sense to use Prepolymers with higher viscosity at room temperature either by dissolving them in suitable solvents in low viscosity To transfer prepolymer solutions or the prepolymers directly in a suitable solvent or the prepolymers before processing in the countercurrent injection machines to higher temperatures up to 150 ° C, preferably between 80 to 130 ° C, to thereby heat the to achieve the desired reduction in viscosity below 2000 cP. Preferably in the invention Process used NCO prepolymers which have two terminal isocyanate groups.

Suitable solvents are those with the isocyanate groups of the prepolymers and the Chain lengthening agents little or no

b5 respond. Suitable solvents are ketones, such as Acetone, methyl ethyl ketone and diisopropyl ketone, also ethers such as diethyl ether, dioxane and tetrahydrofuran, tert-alcohols, such as tert-butanol, esters, such as methyl

tat, ethyl acetate and glycol monomethyl ether acetate, Nitriles, such as acetonitrile and benzonitrile, and also hydrocarbons, such as benzene, toluene and xylene, and halogenated hydrocarbons such as chloroform, methylene chloride, carbon tetrachloride, 1,2-dichloroethane, trichloroethane, tetrachlorethylene and chlorobenzene. As a solvent, slightly with the Prepolymers react, for example formamide. Dimethylformamide. Understood dimethylacetamide and dimethylacetamide.

The prepolymers do not have to be truly molecularly dissolved in the solvents mentioned, but can also include colloidal solutions, plastisols or stable dispersions of the prepolymer in the solvent Act. Preferably, water-miscible solvents with one below 100 ° C. are used

35

40

Chain extenders for NCO prepolymers are compounds that contain at least 2 groups which are reactive towards isocyanate groups and have a molecular weight of 18 to 400. These compounds react with the NCO groups of the prepolymer and build through linkage several NCO prepolymer molecules high molecular weight Polyurethanes or polyurethane ureas. The chain extension reaction is also known. Particularly suitable known chain extenders are: water, aliphatic, cycloaliphatic or aromatic diols or amino alcohols with OH or OH and NH groups and aliphatic, cycloaliphatic or aromatic amines, including the Hydrazine. Examples of such chain extenders are:

Ethylene glycol, diethylene glycol,

1 ricinyicügiyiCöi, rFOpänuiöl-l, z,

Propanediol-ΙΛ dipropylene glycol, Thiodiglycol, butanediol-1.2, -13, -23 and -1.4,

3-chloropropanediol-1 2nd pentanediol-1,5,

2-methylpentanediol-2,4,3-methylpentanediol-2,4,

2J2-dimethylpropanediol-13. Butene-2-diol-1,4,

Butyne-2-diol-1.4, hexanediol-2,5, Cyclohexanediols, 1,6-hexanediol, N-methyldiethanolamine, N-ethyldiethanolamine, Diethanolamine, diisopropanolamine, N, N'-bis- {3-aminopropy]) - ethylenediamine, N, N'-bis (2-aminopropyl) ethylenediamine, N, N'-bis (2-aminoethyl) ethylenediamine, N, N'-bis (2-aminopropyl) -ethylenediamine, N, N'-bis- {2-aminoethyl) -ethylenediamine,

4,4'-dimethylaminodiphenylmethane,

4,4'-dimethylamino-33'-dimethyldiphenylmethane,

Hexanetriol, glycerine, triethanolamine, Trimethylolpropane, pentaerythritol, Tris (hydroxyalkyl) phosphites, glucose,

2,2-bis (p-hydroxyphenyl) propane,

4,4'-diaminodiphenylmethane.

2,4- or 2,6-diaminotoluene

or adducts (molecular weights in the

Usually from 200 to 1500) of alkylene oxides,

such as ethylene oxide, propylene oxide or butylene oxide,

of such low molecular weight compounds

active hydrogen atoms or water.

Preferred chain extenders to be used in the process according to the invention are, in addition to es always present water such compounds that are compared to isocyanate groups Water significantly increased responsiveness

so

55

60 have, especially diamines, such as. B. Ethylenediamine, Hexamethylenediamine, 2,4-diaminotoluene, 4,4'-diaminodiphenylmethane or 33,5-trimethyl-5-aminomelhylcyclohexylamine. If desired, if the The aim is to produce dispersions of crosslinked polyurethanes, including tri- and higher-functional ones Chain extenders are also used, as described, for example, in DE-PS 12 82 962 is.

In the process according to the invention it is also possible to use chain extenders which contain ionic groups and which either preferably have 2 or more than isocyanate groups have reactive groups, preferably amino groups, and ionic centers, or else Compounds that have only one opposite isocyanate group pCn rCoiMiGnSiaitigC wPUppC, VGrZügS ^ VCiSC CitiC ΛΛιιιίϊΐΟ- group, and have ionic centers and the used exclusively for the purpose of incorporating ionic groups. When using the latter Compounds monofunctional with respect to isocyanate groups are recommended to avoid a Chain termination the simultaneous use of an at least trifunctional component. examples for such ionic compounds are the alkali or ammonium salts of

1. aliphatic, cycloaliphatic ^ aromatic and heterocyclic mono- and dia.ninocarboxylic acids, such as glycine α- and ^ -alanine, 5-aminocaproic acid. 4-aminobutyric acid, the isomeric mono- and diaminobenzoic acids, the isomeric mono- and diaminonaphthoic acids, lysine and ornithine. Lysine and N- (2-aminoethyl) -2-aminopropionic acid are particularly preferred:

2. aliphatic, cycloaliphatic ^ aromatic and heterocyclic mono- and diaminosulfonic acids, such as

Taurine, methyitaurine, sulfanilic acid,

2,4-diaminobenzenesulfonic acid,

2-aminodiphenylaminosulfonic acid, 2-aminobenzene-N-methanesulfonic acid, 4,4'-diaminodiphenyl-disulfonic acid-2,2 ', 2,4-diaminotoluenesulfonic acid-5,

Naphthylamine-1-sulfonic acid and Aminomethanesulfonic acid. Are particularly preferred N- (2-aminoethyl) -2-aminoethanesulfonic acid, N- (2-aminoethyl) -l-aminomethanesulfonic acid, N- (2-aminoethyl) -3-aminopropanesulfonic acid

and N- (2-aminoethyl) -4-aminobutanesulfonic acid.

3. aminophosphoric acids and aminophosphonic acids,

how

Colamine phosphoric acid, NH ₂ -CH ₂ -CH ₂ OPO ₃ H ₂ , Aminomethylene phosphoric acid,

NH ₂ -CH ₂ -PO ₃ H ₂ ,

Aminopropane phosphoric acid, NH ₂ -CH ₂ -CH ₂ -CH ₂ -PO ₃ H ₂ ,

4-aminobenzenephosphonic acid, 4-aminophenylmethanophosphonic acid, 3-aminomethylbenzenesophosphonic acid, 2-aminobenzoiphosphonic acid, 4-methylaminobenzenephosphonic acid, 4-amino-2-hydroxybenzene-phosphonic acid, 5-aminonaphtha) in-2-phosphonic acid,

Phosphorous acid monor {2-aminomethyl) -

isopropyl ester,

Phosphoric acid mono- (2-methylamino) ethyl ester, phosphoric acid (2-amino-2-carboxy) ethyl ester
and phosphoric acid bis-aminoethyl ester;
4. Addition products of unsaturated acids, such as acylic acid, methacrylic acid, vinyl sulfonic acid and styrene sulfonic acid, addition products of unsaturated nitriles and esters such as acrylonitrile and methyl methacrylate, addition products of the reaction products of olefins with sulfur trioxide, such as carbyl sulfone, 1,3-sultones, such as from cyclic sulfates, such as glycol sulfate, to aliphatic, cycloaliphatic, aromatic and heteroaromatic amines, such as 1,2-ethylenediamine, 1,6-hexamethylenediamine, the isomeric phenylenediamines, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylene hexamine, optionally alkylated hydrazines and ammonia.

Instead of the salts mentioned, the corresponding acids can also be used in the process according to the invention are used, preferably at the same time in the method according to the invention corresponding amount of a suitable base is used to convert the acid groups into the appropriate transferring salty groups.

Instead of the aforementioned anionic groups or containing groups which can be converted into anionic groups In the process according to the invention, compounds can also contain cationic groups or in cationic groups Groups convertible and containing isocyanate-reactive groups Connections are also used. Such compounds are in particular tertiary nitrogen having chain extenders, such as N-methyldiethanoiaitiiti, N-Eihyldipröpariolarnin or the corresponding Ammonium salts.

The amount of ionic groups or ionic groups to be used in the process according to the invention Compounds containing groups which can be converted into groups (ionically modified polyisocyanates, ionically modified higher molecular weight compounds with isocyanate-reactive groups and / or the last-mentioned low molecular weight compounds with ionic groups) is chosen so that in the ultimately obtained dispersed polyurethanes 0 to 200 and preferably 2 to 100 milliequivalents per 100 g of polyurethane are present.

The countercurrent injection machines suitable for the process according to the invention are preferably apparatuses without stirrers which have a mixing chamber, preferably with a volume of 0.5 to 5 cm ³ , which is preferably provided with two injection nozzles and an outlet opening for the mixture One of the components to be mixed is compressed to a pre-pressure of 20 to 500, preferably from 50 to 250 atmospheres and mixed with the other component or components through a nozzle in the mixing chamber 2000 cP, each of the components to be mixed in the process according to the invention is pressed into the mixing chamber through a separate nozzle claimed A device can be used in which the low-viscosity component is injected into a high-viscosity component flowing out of a channel. Countercurrent injection apparatuses which are suitable for the process according to the invention and have at least two injection nozzles are cited in the parts of the literature cited at the outset. These mixing units suitable for the process according to the invention have a mixing output of 50 to 5000 watts / cm ³ with a maximum output of 3 to 200 kg per minute and a chamber volume of 0.5 to 5 cm ³ .

When carrying out the process according to the invention, the components are separated from one The reservoir is guided to the mixing chamber under pressure, preferably via multi-cylinder piston pumps.

The process is carried out at a temperature at which the components are liquid and their viscosity is preferably less than 200 ocP; Temperatures in the range from 0 to 150 ^° C. are preferred. Prepolymers which are too viscous at low temperatures can be brought to the desired viscosity by heating or adjusted to processable viscosities by using a relatively small amount of solvent.

In the event that the components only at increased If the temperature has the required viscosity, storage tanks, pump units and lines are used heated.

The prepolymer (solution) and the liquid phase can of course be at different temperatures be promoted and mixed.

The increased temperature naturally accelerates the process before, during or after the mixing or Polyaddition reaction taking place in emulsification.

It has been found to be advantageous for mixing by countercurrent injection that the aqueous phase emulsifiers or auxiliaries which reduce the emulsifiability of the prepolymer or the prepolymer solution increase in the liquid phase, adds. These are connections that go to Manufacture of oil-in-water emulsions and water-in-oil emulsions can be used, as well as around anion-active, cation-active, ampholytic and non-ionic compounds, as they are in Römpps Chemie-Lexikon, 7th edition, Franckh'sche Verlagshandlung, W. Keller & Co, Stuttgart, 1973, pages 1009-1013, and in Kirk-Othmer, Bad. 8, pages 117-154, and Ullmann Vol. 1, pages 717-724.

Together with or instead of the emulsifiers, so-called laminators (see BE-PS 7 18 029) or ionic or hydrophilic polyurethanes, which are optionally present dispersed in water, used will. Such polyurethane dispersions are, for. B. in DE-OS 14 95 745, 14 95 847 and 17 70 068 or the US-PS 34 79 310 described.

The emulsifiers or the additives mentioned are in the aqueous phase in a concentration of Contain 0.01 to 40 wt .-%, preferably a concentration of 0.1 to 10 wt .-% is used

The molar amount of chain extender generally corresponds to the molar amount of existing NGO groups; the molar ratio of NCO:

[H] * - is preferably 1 ([H] * = molar concentration of NCO reactive groups). Smaller amounts of chain extender can also be used (NCP: [H] / t> 1), but also larger amounts up to about

NCO: [H] / c ratio = 1.8, preferably 1.5; Then it will be the molecular weight of the polyurethanes or polyurethane ureas is lower and thus their melting point lower.

The chain extender can be added before, during or after the mixing of the prepolymer or the dissolved prepolymer with the aqueous phase. Should the chain extension center! before are added to the mixture, it is advantageous to dissolve or emulsify it in the aqueous phase. If the addition takes place during mixing, it is advisable to use a 3-component mixing chamber, into which the optionally dissolved prepolymer, the aqueous phase and the chain extender are injected simultaneously. In all cases, the material applied from the mixing chamber! to carry out the chain extension reaction stirred and - if the components are mixed at an elevated temperature - while cooling to room temperature.

Is carried out with the aid of solvent, whose presence in the final dispersion or suspension is undesirable so it is advantageous to the organic solvent at 20 to 10O ⁰ C, preferably distill off at 40 to 70 ° C, at reduced pressure. Another method is to blow out the solvent with air or nitrogen.

The prepolymers used in the process according to the invention preferably have an NCO content of 1 to 15% by weight, in particular 1 to 5% by weight. The prepolymers are processed either in bulk or in the form of solutions in the solvents already mentioned, the solutions having a solids content of at least 50, preferably at least 70% by weight. When working without solvent preferably aimed viscosity range of 50 to 2000 can, especially from 300 to 1500 cps by heating the prepolymers to a maximum of 150 ⁰ C, preferably at 80 to 130 ⁰ C, are set. In the process according to the invention, the amount of water is chosen so that 15 to 55 percent, preferably 20 to 40 percent, aqueous dispersion is obtained.

The dispersions produced by the process according to the invention can be suitable for the production of polyurethane (urea) powders. The powder is obtained by separating the liquid phase from the solid phase, e.g. B. by decanting, filtering or centrifuging, and the resulting solid is dried in a suitable manner, optionally with mechanical agitation, optionally under reduced pressure and optionally with the addition of auxiliaries which accelerate the drying. Depending on the size of the polyurethane (urea) particles in the dispersion, very fine to coarse powders are obtained.

As aqueous dispersions, the products of the process are also particularly suitable for coating and impregnation of paper, textiles, leather, fleece, wood and metals and as adhesion promoters, adhesives, binders or Laminating agent suitable Furthermore, dipping articles, foams according to the latex foam whipping process, by adding electrolyte coagulates can be obtained, which in the usual way on the mixing roller are further processed.

The dispersions can be blended with polymer or copolymer dispersions of the same charge will. Fillers, plasticizers, pigments, carbon black, aluminum, clay, asbestos and tar dispersions can be incorporated.

The dispersions generally flare immediately to form stable foils and plastic coatings. From dispersions of uncrosslinked polyurethanes can in the presence of polyfunctional, crosslinking substances such as formaldehyde or Formaldehyde-releasing substances or substances that react like formaldehyde, such as carbamide or phenolic resins, blocked polyisocyanates and polyepoxides

ίο networked coatings are obtained.

example 1

A countercurrent injection mixing unit is used, as described in principle in "Kunststoff-Handbuch", Volume VI, "Polyurethane", Carl-Hanser-Verlag Munich (1966), pages 180 ff. The unit has a mixing chamber volume of 0.5 cm ³ and has a maximum discharge rate of 15 kg / min. One such machine is under the

Designation HK i5 (Maschinenfabrik Hennecke) available in stores. The selected nozzle diameter correspond to the specified pressure, viscosity and quantity ratios.

A prepolymer with an NCO content of 3.1 percent by weight, made from 1.8 moles of hexamethylene diisocyanate and 1 mole of a mixed polyester of adipic acid, 1,6-hexanediol and neopentyl glycol with an average molecular weight of 1700, is applied over this HK 15 at a pressure of 200 atmospheres , with a 6.7% solution of an ethoxylated nonylphenol (30MoI ethylene oxide / mole nonylphenol) in water, which was also injected with a nozzle pressure of 200 atmospheres. The prepolymer is at a temperature of 110 to 120 ⁰ C and a

Viscosity of about 1450 cP, the aqueous solution with a temperature of 25 ° C and a viscosity of 2 to 3 cP processed. The components are in a weight ratio of prepolymer: aqueous solution = 1: 2 in the mixing chamber promoted.

After discharging with stirring, the mixture has 90% of the calculated NCO content equivalent amount of a 1 η solution of N- (2-aminoethyl) -2-aminoethanesulfonic acid Sodium chain-extended in water. After a few hours of stirring while cooling to room temperature and diluting with With water, a finely divided stable dispersion with a solids content of 17.5% is obtained.

Example 2

a prepolymer with 3.1 wt 1.8 moles of hexamethylene diisocyanate and 1 mole of a mixed polyester of adipic acid, 1,6-hexanediol and Medium molecular weight neopentyl glycol

of 1700, with a 5% strength anionic aqueous dispersion also compressed to 200 atmospheres of a polyurethane urea which, according to the teaching of US Pat. No. 3,479,310, consists of 209 g of an adipic acid-hexanedioI-neopentyl glycol mixed ester (medium molecular

weight 1700), 38 g of 1,6-diisocyanatohexane, 13.8 g of a 43% strength aqueous solution of N- {2-aminoethyl) -2-aminoethanesulfonic acid sodium salt, 1.9 g of 1,2-diaminoethane and 330 g of water prepared and then diluted with water to a solids content of 5%, mixed. The prepolymer has a temperature of 110 to 120 ⁰ C, a viscosity of about 1450 cP; the aqueous dispersion has a temperature of 25 ° C. and a viscosity of approx. 1 cP. the

Components become prepolymer in weight ratio : aqueous dispersion = 1: 2 conveyed into the mixing chamber.

After being poured out with stirring, the mixture has 80% of the calculated NCO content equivalent amount of a 1 η solution of N- (2-aminoethyl) -2-aminoethanesulfonic acid Sodium in water cat-elongated. After a few hours stir in Cooling to room temperature and dilution with water gives a finely divided, redispersible Suspension with a solids content of 27.4%.

Example 3

A prepolymer with 2.8% by weight of NCO, produced from 1.8 mol of hexamethylene diisocyanate and 1 mol of a mixed polyester from adipic acid, hexanediol, b and Neopentyigiykoi with a miuierei'i molecular weight of 1700, a 5% solution of the ethoxylated nonylphenol used in Example 1 in water and an aqueous solution of N- (2-Aminoethy!) -2-aminoethanesulfonic acid sodium and ethylenediamine mixed. The two chain extenders are contained in the aqueous solution in a molar ratio of 1: 1. The prepolymer has a temperature of 110 to 120 ° C and a viscosity of about 145OcP, the aqueous solution of the chain extender has a temperature of 25 ^C Z and a viscosity of about 1 cP, and the aqueous solution of ethoxylated nonylphenol having a temperature of 25 ° C and a viscosity of approx. 2.5 cP.

The components are in a weight ratio of prepolymer: solution of chain extenders = 1: 0.25 and prepolymer: solution of the ethoxylated nonylphenol =! : 1.2 dosed into the mixing chamber, where the concentration of the Ketienverläp.gerungsmittel in the aqueous solution is chosen so that it is 80% equivalent to the NCO content of the prepolymer.

After discharge, the mixture is stirred for a few hours while cooling to room temperature and filtered through a sieve with a pore size of 0.1 mm. The filtrate forms a finely divided, redispersible suspension with a solids content of 31.4%.

Example 4

A HK 100 (this machine the HK 15 corresponds with the difference that the chamber volume is 1 ^cm3, and the maximum discharge rate at 100 kg / min. Total mixture is) are each charged with 100 atm nozzle pressure, a prepolymer with 3.2 wt. -% NCO, prepared from 1.8 mol of Haxamethylene diisocyanate and 1 mol of a mixed polyester of adipic acid, 1,6-hexanediol and neopentyigiykoi with an average molecular weight of 1700, mixed with a 3% solution of the ethoxylated nonylphenol used in Example 1 in water. The prepolymer has a temperature of 95 to 115 ° C. and a viscosity of approx. 1650 cP, the aqueous solution has a temperature of 25 ° C. and a viscosity of approx. 2 cP. The components are fed into the mixing chamber in a prepolymer: aqueous solution weight ratio of 2: 3

Immediately after the mixing of the theory, with respect to the chain-extended Gcsamtisocyanatrncnge 80%, with a 40% aqueous solution of N- (2-aminoethyl) ^-2-r aminoethansuIf onsaurem sodium is used. A dispersion of 40% is obtained

Solids content that is diluted to 30% solids with water and is stable. The dispersion is finely divided, the particle diameter is approx. 230 μm.

Example 5

A 70% acetone solution of a prepolymer with an NCO content of 1.6% by weight is mixed with a 1% aqueous solution of an ethoxylated nonylphenol via an HK 15 with 80 atmospheric nozzle pressure each. The prepolymer was prepared from 1,8MoI hexamethylene diisocyanate and 1 mole of a polyester of adipic acid and 1,4-butanediol having an average molecular weight of 2250. The prepolymer solution has a temperature of 45 to 5O ⁰ C and a viscosity of about 40OcP; the aqueous solution has a temperature of 25 ° C. and a viscosity of approx. 1 cP. The components are in a weight ratio of prepolymer solution: aqueous solution . * O: "j: - k4: rAlnmmor" m γψαΛΪ ic "

SU I Ig - 1 * I, CJ III UIt. tVl 13V ·! (IVU 11 Il U ^ i Viil ^ vuuju

After discharge, the mixture becomes 85% of the calculated NCO content with stirring equivalent amount of a 1 n-propylenediamine solution in water. After a few hours The suspension obtained is stirred while cooling to room temperature by decanting water and acetone freed and the residue dried in a vacuum of 12 Torr over a desiccant. That so obtained thermoplastic polyurethane urine powder has a high proportion of fines and has a melting range of 140 to 160 ° C.

Example 6

An acetone prepolymer solution and a 10.7% solution of 1,2-propylenediamine in water mixed together.

The acetone prepolymer solution is prepared as follows:

9500 g of a He -andiolpolycarbonates with a Molecular weight of 1870 are dewatered at 120 ° C / 15 Torr. At 106 ° C., 1510 g of hexamethylene diisocyanate are added to, holds 1 hour at 100 ° C and allowed to cool to 60 ° C in the course of a further hour. Now you add 80 g of N-methyldiethanolamine dissolved in 705 g of acetone are added. holds approx. 3 hours at 60 ° C and dilutes with a further 2000 g of acetone. The next day is heated to 55 ° C and quaternized with 6.2 mol of dimethyl sulfate, dissolved in 8420 g of acetone (45 min. at 50 ° C.).

22,340 g of a 50% strength solution of a weakly cationic prepolymer are obtained. NCO = 1.42% by weight.
η 25 ⁰ C = 182 ep.
τ / 50 "C = 125 ep.

The temperature of the components is 25 ° C. The components are prepoly in the weight ratio mer solution: diamine solution as 1: 1 in the mixing chamber mer promoted. A sedimenting « Suspension which, after decanting and drying, eir thermoplastic polyurethane urea powder of Melting point 140 to 146 ° C results.

Example 7

Repetition of example 6, the aqueous diamine solution being 6%, based on total solids 15%, cationic polyurethane dispersion, that is, according to the teaching of US Pat. No. 3,479,310 from 9700 (7 mol) of a tetraethylene glycol-1,6-hexanediol poly carbonate (molar ratio 5: 2), 1800 g of 1,6-diisocyanate

tohexane, 214 g of N-methyldiethanolamine, 214 g of dimethyl sulfate, 25 g of hydrazine hydrate, 58 g of 1,6-diaminohexane, 400 g of 20% phosphoric acid, 200 g of 30% formaldehyde and 24,000 grams of water was prepared and then diluted to 15% solids with water (mean particle size 144 πιμ), are added. That Polyurethane urea powder obtained from the batch is somewhat finer, with the same melting point. The mean particle diameter is 43 μm.

Claims (6)

Patent claims: 1. Process for the continuous production of aqueous polyurethane dispersions by mixing a liquid? or a prepolymer which is dissolved in an organic solvent and has terminal isocyanate groups and has at least two NCO groups in the molecule, which through Reaction of di- or polyisocyanates with compounds with at least two active hydrogen atoms with a molecular weight of 400 to 10,000 has been obtained, with water and optionally with the addition of chain extenders having at least two isocyanate-reactive groups with one Molecular weight from 18 to 400 before, during or after the mixing of the prepolymer with the aqueous phase or of only one isocyanate-reactive group and compounds containing ionic centers as well optionally with the use of from 0.01 to 40% by weight, based on the aqueous phase, of one Emulsifier, laminator, ionic or hydrophilic polyurethane, characterized in that that the mixing of the starting components by the countercurrent injection process performs, with at least one of the components to be mixed on a pre-pressure of 20 is compressed to 500 atmospheres and mixed with the other components through a nozzle in the mixing chamber. 2. The method according to claim 1, characterized in that there is such a liquid prepolymer having terminal isocyanate groups used, the viscosity of which is between 50 and 2000 cP at the processing temperature. 3. Process according to Claims 1 and 2, characterized in that there are ionic groups having prepolymers is used. 4. Process according to Claims 1 to 3, characterized in that chain extenders containing ionic groups are used. 5. Process according to claims 1 to 4, characterized in that the mixing is carried out in a countercurrent injection apparatus, the mixing chamber of which has a volume of 0.5 to 5 cm ³ . 6. Use of the aqueous polyurethane dispersions prepared according to claims 1 to 5 for Manufacture of polyurethane powders.