DE2344135A1 - PROCESS FOR THE CONTINUOUS PRODUCTION OF POLYURETHANE DISPERSIONS - Google Patents

Description

Bayer Aktiengesellschaft

Central area of patents, trademarks and licenses

509 Leverkusen, Bayerwerk

3 AUG. 1 1973

Wr / Seh-b

Process for the continuous production of polyurethane dispersions

The present invention relates to a new continuous one Process for the preparation of aqueous polyurethane dispersions. Under the term "polyurethane dispersions" are here both aqueous dispersions or suspensions of pure polyurethanes and of polyurethane ureas to understand.

Such polyurethane urea dispersions are, for example described in Angew. Chem. 8 £ (1970) 53 and in Angew. macromol. Chem. 2-6 (1972) 85.

Die-production of disperse polyurethanes and polyurethane ureas happens according to an older proposal (German patent application P 23 11 635.0) so that the for this Systems required starting components are introduced into a zone of high turbulence and there the polyaddition and formation of a disperse phase take place. As a zone of high turbulence, a space is understood through which - with intensive mixing - at least 300 parts by volume of liquid per part by volume of the room and per hour.

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B 0 9 B 1 1/0 Π B Π

The conventional device for creating a zone of high turbulence consists of a stirred tank with a stirrer and possibly a baffle. For discontinuous The production of dispersions and bus boarding is mainly done with such mixing units.

Are suitable for better mixing reactors as t in the German patent application 22 60 870.4 or Kreiselhoraogeiiinatoren, as described in the German patent application P 23 11 t> 55.Q. These machines have the advantage that they enable continuous production.

However, all devices used to date for the production of dispersions and suspensions - mainly on polyurethane and Polyurethane urea base - has the disadvantage that mechanically agitated for mixing the starting components Aggregates are used. This keeps your throughput at 300-10,000 parts by volume of liquid per part by volume of the Space and per hour and their mixing performance is limited to the

-1 3

richly limited by 10 to 25 watts / cm.

It has now surprisingly been found that polyurethane (ureas) can be produced continuously as a dispersion or suspension can if you have a liquid prepolymer or a prepolymer solution by countercurrent injection with a liquid phase, if necessary

using emulsifiers or other suitable auxiliary

■ if applicable
medium, mixed and / before, during or after mixing a chain extender.

The fact that fluids can be obtained by countercurrent injection can mix intensively with each other is known. On the Mixing is based on the principle of counter-current injection liquid components with the help of counter-current injection

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.5.

Machines such as those used in the production of polyurethane foams. As from the literature, e.g. Ii. in High Polymers, Vol. WI, "Polyurethanes, Chemistry and Technology", written by Saunders-I'Yiseh, Interscience Publishers, New York, London, Volume II, 1904, Seile 195, and from the specialist literature, -a. B. Leaflet Order No. 1) 1) 572G from 1.8.1965, Bayer Leverkusen, "Moltopren Verdüsimgsmaschinen Typ" IIK ", or" Mobay Equipment Report "No. 3, Mobay Chemical Company, Penn Lincoln Parkway West, Pittburgh , Pennsylvania and in particular also from "Kunststoff-Handbuch", Volume VII, "Polyurethane", Carl-Hanser-Verlag Munich (1966), pages 149 ff., Such countercurrent ektionsmasehinen have long been known prior art.

The advantage of using such countercurrent injection machines in the production of polyurethane dispersions consists in particular in the fact that the per part by volume of the room and fluid volumes mixed per unit of time is larger than with the previously used mixing units. For example, a machine of the type HK 15 (more details Description see example 1) with a mixing chamber volume of 0.5 cm and an output of 180 kg / hour 360,000 parts by volume per part by volume of the room and per hour, if you consider the mean density of the discharged Material assumes 1 g / cm. A machine of the type HK 100 with a

3
Mixing chamber volume of 1 cm and a discharge of 20 kg per minute or a machine of the type HK 1000 with a mixing chamber

3
Volumes of 5 cm and an output of 100 kg per minute mix in the same way 1,200,000 parts by volume per part by volume of the room and per hour.

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During the mixing in the intensely stirred kettle in general IO -10 'Walt / on' and the ijpevdelle iVlisch power of KreiHrlhomogriiisioruiiisc-hmen 25 vVaU / c-m " nic.hi exceeds, scored / .. H. a machine of the type IlK 100 mil ei.nc.-tn mixed chamber volume of 1 CMn "and an Austraq» on 20 kg per minute, which with 150 aiii form a mixing performance of c-n. 5000 vVatf / em 'at 100% Mixing. Even with a mixing efficiency of only 10%, the misalignment would still amount to approx. 500 watts / cm ".

The high Mischleisi ung, the liquid using the Gegenslrorninjektionsprin- / Aps when mixing components with the aid of HK-machines is achieved, which all exceed previously for the preparation of dispersions and suspensions methods employed.

Another advantage is that the zone of high turbulence is only an extreme small mixing room is used, which in contrast to the usual mixing units is particularly easy to clean.

The fact that polyurethane dispersions in such countercurrent injection machines can be produced, is surprising insofar as such machines have not been used to date. Position / polymer dispersions in water were used because of difficulties such as coagulum formation and nozzle clogging Was to be expected when liquids with such different viscosity, as explained in accordance with below Invention are used, are mixed with a high flow rate. In contrast, it was surprisingly found that even with a viscosity ratio of more than 1: and up to 1: 1500, perfect dispersion without coagulum formation entry. Coagulate formation had to be expected in particular, since it is part of the known state of the art that

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l'olyiner or plastic dispersions when exposed to coagulate high shear forces.

The present invention is thus a Process for the continuous production of aqueous polyurethane dispersions by mixing a liquid one or one dissolved in an organic solvent isoeyanate-terminated prepolymers with water and, if necessary, chain extenders with at least two isocyanate-reactive groups Groups, if necessary with the use of emulsifiers and / or other auxiliaries, thereby kermselehnet, that the mixing of the starting components takes place according to the reverse injection method.

The present invention also relates to the use of the polyurethane dispersions thus accessible for Manufacture of polyurethane powders.

For the purposes of the invention, prepolymers are reaction products of di- or Polyisocyanates with compounds with at least two active hydrogen atoms from a molecular weight of approx. 400 to 10,000, the at least 2 NCO groups per molecule. This means that in the reaction per mole of active hydrogen at least 2 moles ! TCO groups must be available.

Such prepolymers are known. To their production sets in general, polyols of the appropriate molecular weight are used with excess di- or polyisocyanates.

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Particularly suitable polyols have a molecular weight of 400 to 10,000, preferably 500 to 4000 and 2 to 3 hydroxyl groups, preferably 2 hydroxyl groups per molecule. Preference is given to using polyesters, polyethers, polythioethers, polyacetals, polycarbonates and polyesteramides of the type known per se as polyols. Examples of suitable polyesters are conversion products of polyvalent, preferably dihydric and optionally additionally trihydric alcohols with polybasic, preferably dibasic carboxylic acids. In addition to the free polycarboxylic acids, it is also possible to use the corresponding polyenic anhydrides or corresponding polycarboxylic acid esters of lower alcohols or mixtures thereof for the production of the polyesters. DLe polycarboxylic acids can be aliphatic, cycloaliphatic! -, aromatic and / or heterocyclic in nature and, if necessary, z. B. substituted by Ilalogenatome and / or unsaturated. Examples are: succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, trimellitic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrachlorophthalic anhydride, trachlorophthalic anhydride, trimachlorophthalic anhydride, detrachlorophthalic anhydride, detrachlorophthalic anhydride, detrachlorophthalic anhydric acid, maleic anhydrophic anhydride, maleic anhydride, and maleic anhydride, such as Mixture with monomeric fatty acids, dimethyl terephthalate, bis-glycol terephthalate. As polyhydric alcohols such. B. Ethylene glycol, propylene glycol (1, 2) and - (1,3), butylene glycol (l, 4) and - (2, 3), hexanediol (1, 6), octanediol-d, 8) , Neopentyl glycol, cyclohexanedimethanol (1,4-bis-hydroxymethylcyclohexane), 2-methyl-1,3-propanediol, glycerine, trimethylolpropane, hexanetriol- (1, 2, 6), butanetriol- (1, 2, 4), trimethylolethane, Pentaerythritol, quinitol, mannitol and sorbitol, methyl glycoside in question.

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

Polycarbonates containing hydroxyl groups are those of the type known per se. B. by implementing Diols such as propanediol (1, 3), butanediol (1, 4), and / or hexanediol (1, 6), Diethylene glycol, triethylene glycol, tetraethylene glycol with diaryl carbonates, E.g. diphenyl carbonate can be produced with dialkyl carbonates such as diethyl carbonate or phosgene.

The polyester amides and polyamides include, for. B. the multi-valued ones saturated and unsaturated carboxylic acids or their anhydrides and polyvalent saturated and unsaturated amino alcohols, Predominantly linear condensates obtained from diamines, polyamines and their mixtures.

Also polyhydroxyl compounds already containing urethane or urea groups and optionally modified natural polyols, such as castor oil, carbohydrates, starch, can be used. Also addition products of alkylene oxides to phenol-formaldehyde resins or to urea -iOrmaldehydharze are used as a polyol component for. Prepolymers can be used.

Representatives of these compounds to be used according to the invention are z. 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, and in the Kunststoff-Handbuch

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Volume VII, Vieweg-IIöchtlen, Carl-Hanser-Verlag Munich, 1966, z. B, adf on pages 45-71.

Suitable di- or polyisocyanates for converting the polyols to the prepolymers containing isocyanate groups are aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic polyisocyanates (cf. Ann. 562, pages 75-136), for example ethylene diisocyanate, 1,4-tetramethylene diisocyanate , 1,6-hexamethylene diisocyanate, 1,12-dodecane diisocyanate, cyclobutane-1,3-diisocyanate, cyclohexane-1,3 and 1,4-diisocyanate and any mixtures of these isomers, l-isocyanato-3, 3, 5- trimethyl —S-isocyanatomethylcyclohexane, 2,4- and 2,6-hexahydrotolylene diisocyanate and any mixtures of these isomers, hexahydro-1,3 and / or 1,4-phenylene diisocyanate, perhydro-2,4 'and / or 4, 4 ' -diisocyanate, 1, 3- and 1, 4-phenylene diisocyanate, 2, 4- and 2, 6-tolylene diisocyanate and any mixtures of these isomers, diphenylmethane-2, 4 ^S - and / or -4, 4' - diisocyanate, naphthylene-1,5-diisocyanate, triphenylmethane-4, 4 ', -4 "-triisocyanate, polyphenyl-polymethylene-polyisocyanate nate (obtained by aniline-formaldehyde condensation and subsequent phosgenation according to British patents 874 430 and 848 671), perchlorinated aryl polyisocyanates (cf. German interpretation document 1.157. 601), polyisocyanates containing carbodiimide groups (cf. German patent specification 1,092,007), diisocyanates, according to US patent specification 3,492,330, polyisocyanates containing allophanate groups (cf. British patent specification 994.890, Belgian patent specification 761.626 and Dutch patent application 7.102.524) Polyisocyanates containing isocyanurate groups ('German patent specifications

1,022,789, 1,222,067 and 1,027,394; German disclosure documents 1.929.034 and 2.004.048), polyisocyanates containing urethane groups

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(see Belgian patent 752,261; US patent 3,394,164), acylated Polyisocyanates containing urea groups (cf. German Patent 1.230.778), polyisocyanates containing biuret groups (cf. German patent specification 1.101. 394, British Patent 889,050; French patent 7,017,514), by telomerization reactions produced polyisocyanates (cf. Belgian patent specification 723,640), polyisocyanates containing ester groups (cf. British patents 956,474 and 1,072,956; U.S. Patent 3,567,763; German patent specification 1,231. 688), reaction products of the above-mentioned isocyanates with acetals (cf. German patent specification 1,072,385).

The preparation of prepolymers containing isocyanate groups from the polyols and isocyanates is 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, for example, in DOS 1,770,06S. The ionic modification can also be carried out on the prepolymers (solutions) during or after their preparation. The preparation of ionically modified prepolymers can, for example, also be carried out in such a way that polyols containing tertiary nitrogen atoms, in particular polyhydroxy polyethers, are used for the preparation of the prepolymers, which before or after the reaction with the polyisocyanate is converted into ^{compounds containing = ¥ +} = groups by a quaternizing agent will. Ionically modified HC0 prepolymers obtainable according to German patent specification 1 282 962 can also be

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• 40.

inventive method are used. In the process according to the invention, ionically modified NGO prepolymers can be used which have an ionic group content, in particular of = N ⁺ =, -OOCf or -SO ₅ ", of about 2 to about 200 milliequivalents per 100 g.

Even non-ionically modified prepolymers, such as those used for Production of polyurethane dispersions according to DOS 2 141 805 » DOS 2 141 ÖO7, German patent application P 23 14 513.3 or German patent application P 23 14 512.2 are used, can be used according to the invention. It can also Mixtures of the above prepolymers are used.

For the process according to the invention, prepolymers are preferably used whose viscosity at the processing temperature is below 2000 cP, preferably between 50 and 1500 cP, since they are particularly suitable for processing in countercurrent injection machines. It therefore makes sense to convert prepolymers with a higher viscosity at room temperature either by dissolving them in suitable solvents into low-viscosity prepolymer solutions, or to produce the prepolymers directly in a suitable solvent, or else to convert the prepolymers to higher temperatures of up to 150 before processing in countercurrent machines ⁰ G, preferably 80 - 130 ⁰ C to heat to thereby achieve the desired Viskositätserniedrxgung below 2000 cP. In the process according to the invention, preference is given to using NGO prepolymers which have two terminal isocyanate groups.

As a solvent, sdbhe come with the isocyanate groups the prepolymers and the chain extenders do not

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or react little. Suitable solvents for the purposes of the invention are ketones such as B. acetone, methyl ethyl ketone, diisopropyl ketone, also ethers such as diethyl ether, dioxane, tetrahydrofuran, tert. Alcohols such as tert-butanol, esters such as methyl acetate, ethyl acetate, glycol monomethyl ether acetate, Nitriles such as acetonitrile, benzonitrile and hydrocarbons such as benzene, toluene, xylene and halogenated hydrocarbons such as chloroform, methylene chloride, carbon tetrachloride, 1,2-dichloroethane, trichloroethane, tetrachlorethylene, chlorobenzene. as Solvents which react slightly with the prepolymers are, for example, formamide, dimethylformamide, dimethylacetamide, dimethyls ulf oxide understood.

The prepolymers do not have to be genuine in the solvents mentioned be molecularly dissolved, but it can also be colloidal solutions,

Plastisols or stable dispersions of the prepolymer in the solvent .handeln. Water-miscible solvents with a boiling point ^{below 100 ° C. are preferably used.}

Chain extenders for HCO prepolymers are compounds those per molecule preferably 2 versus isocyanate groups have reactive G groups and a molecular weight of 18 - approx. 400. These connections respond with the NCO groups of the prepolymer and build high molecular weight polyurethanes by linking several NCO prepolymer molecules 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

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the hydrazines Examples of such KeUenverlängerer are: ethylene glycol, diethylene glycol, triethylene glycol, propane-l, 2-diol _3-propane l, 3-diol, dipropylene glycol, thiodiglycol, butane-1, 2, -1,3, -2, 3 and -1, 4, 3-chloropi'opanediol-1, 2, I'eniandiol-1, 5, 2- \ Tethy3penlandiol-2, 4, 3 -Me thy Ip ent an diol-2,4, 2, 2- Dimetrylpropanediol-1,3, butan-2-diol-1,4, butyn-2-diol-1,4, llexanediol-2 _J 5, cyclohexanediols, hexanediol-1,6, N-methyl-diethanolaniin, N -ethyl- diethanolamine, dietianolamine, diisopropanolamine, N ₁ N '-bis- (3-aminopi-opyl) -ethylenediamine, N, N' - bis- (2-aminopropyl) -ethylenediamine, N ₃ N '~ bis- (2-aminoethyl) -äthy] enediamine, N, N '-Bis- (2-arninopropyl) - t ethylene diamine, N ₃ N ³ - bis (2-aminoethyl) -äthylendiamiji, 4 ₃ 4' -Dimethylaniino-diphenylmelhan, 4, 4 ' - Dirnethylaniino-3, 3 'dimethyl-diphenyl-methylene, Ilexantriol, glycerin, triethanolamine, trimethyloljropane, pentaerythritol, tris- (hydroxy-alkyl) -phosphite, glucose, bisphenol A, 4, 4' - diamino-diphenyl-methane, 2, 4- or 2,6-diaminotoluene or adducts (molecular weights generally from 200 to 1,500) of alkylene oxides such as ethylene oxide, propylene oxide or butylene oxide with such low molecular weight compounds with active hydrogen atoms or with water. Preferred chain-lengthening agents to be used in the process according to the invention are, in addition to the water that is always present, those compounds which have a significantly increased readiness to react with isocyanate groups compared to water, in particular diamines, such as, for example, ethylenediamine, hexamethylenediamine, 2,4-diaminotoluene, 4,4 '-Diaminodiphenylmethane or S ^ jS-irimethyl-S-aminomethylcyclohexylamine. If desired, if the aim is to produce dispersions of crosslinked polyurethanes, trifunctional and higher-functionality chain extenders can also be used, as is described, for example, in German Patent 1,282,962.

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In the method according to the invention can, too. Ionic Group-containing compounds init used, the either preferably 2 or more than isoeyanate groups reactive groups preferably have amino groups and ionic centers and therefore act as ionic chain oxidizers can be designated or also compounds which only have one isocyanate-reactive group Group, preferably amino group, and ionic centers and which are used exclusively for the purpose of incorporating ionic groups. When using the latter compounds monofunctional with respect to isocyanate groups To avoid chain termination, it is advisable to use at least one trifunctional at the same time Components, examples of such ionic compounds are the JSlcall or ammonium salts of

1. aliphatic, cycloaliphatic !!, aromatic and heterocyclic Mono- and diaminocarboxylic acids, such as glycine ° C- and ß-alanine, 6-aminocaproic acid, 4-aminobutyric acid, the isomers. Mono- and diaminobenzoic acids, the isomeric mono- and diaminonaphthoic acids, lysine, ornithine, etc. Lysine and M- (2-aminoethyl) -2-aminopropionic acid are particularly preferred;

2. aliphatic, cycloaliphatic, aromatic and heterocyclic mono- and Diam'mosulfonsäuren such as taurine, methyl taurine, sulfanilic acid, 2, 4-diaminobenzenesulphonic acid, 2-amino-diphenylaminosulfonsäure, 2-amino-benzene-N-methanesulfonic acid, 4, 4 '-Diaminodiphenyl -disulfonic acid- (2, 2 '), 2, 4-diaminotoluenesulfonic acid- (5), naphthylamine-1-sulfonic acid, aminomethanesulfonic acid, etc. Particularly preferred are U- (2- aminoethyl) -2-aminoethanesulfonic acid, Έ- (2-aminoethyl) ) -1-aminomethanesulfonic acid , ti- (2-aminoethyl) -5-an] iiiopropanesulfonic acid and Ii- (2-aminoethyl) -4-aminobutanesulfonic acid,

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Ά, Nmiiiophosphorsäureii and aminophosphonic acids such as colaine

phosphoric NIl ₀ CH ₀ -C] O I _0] ¹ ₀ OH, aminomethylenephosphonic MII ₁₁ -C-Il ₀ -I ¹ O, Jl _0, aminopropane phosphoric acid NI i _{0 0} -CII -CFI -CH 'O ^1' 11 . ,, 4-Aminoberr / .olphosphonic acid, 4-Amino-phenylmelhanphosphonsäure, 'λ- Aminoniethyl-benzene-phosphonic acid, 2-aminobenzenephosphonic acid, 4- -Vifhylaminobenzenephosphonic acid, 4-Amino-2-hydroxybenzenphosphonic acid, 5-Amino-naphthalen-2 Phosphorous acid, phosphorous acid aono- (2-aminomet.hyl) isopropyl ester, phosphoric acid mono- (2-methylamino-ethyl ester}, phosphoric acid (2-am ino-2-carboxyethyl ester), phosphoric acid-his -aminoethyl ester;

4. addition products of unsaturated acids such as acrylic acid, ■ Methacrylic acid, vinyl sulfonic acid, styrene sulfonic acid, den Addition products of unsaturated nitriles and esters such as acrylonitrile and methyl methacrylate, the addition products of the reaction products of olefins with. Sulfur trioxide such as carbyl sulfate, of sultones such as 1,3-propane sultone, of 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, tetraethylene pentamine, pentaethylene hexamine, optionally alkylated hydrazines and ammonia.

Instead of the salts mentioned, the corresponding. Acids are used in the process according to the invention, preferably at the same time in the process according to the invention Method an appropriate amount of a suitable base is used to convert the acid groups into the appropriate Convict saxz-like groups.

Instead of the aforementioned anionic groups or in anionic Groups can be converted to groups containing compounds

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Processes according to the invention also include cationic groups bsw. groups which can be converted into cationic groups and groups which are reactive toward isocyanate groups Connections are not used. Such connections and in particular chain extenders containing tertiary nitrogen, such as If-Me thy 1-diäthanoiainin, H-ethyl-dipropanolamine bsw. the corresponding ammonium salts.

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

In the countercurrent injection machines suitable for the method according to the invention it is preferably a stirrer-free apparatus that has a mixing chamber, preferably of the volume have 0.5-5 cm, which preferably have two injection nozzles and an outlet opening for the mixture is provided. In the countercurrent injection process, at least one of the components to be mixed is poured onto one Form pressure of 20-500, preferably 50-250 atmospheric pressure and compressed through a nozzle in the mixing chamber with the or the mixed with other components. In general, especially when components to be mixed are present with a viscosity of less than 2000 cP, each of those in the method according to the invention will Components to be mixed are pressed into the mixing chamber through a separate nozzle. When a component is present

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with a viscosity above 2000 cP, however, also, for example, a countercurrent injection device of the type claimed in German patent specification 1 114 313 " Device are used at v / elcher the low-viscosity component in the out of a channel flowing, highly viscous component is injected. At least two suitable for the process according to the invention Countercurrent injection apparatuses having injection nozzles are cited in the literature references cited at the outset. These mixing units suitable for the process according to the invention have a mixing capacity of 50-5000 watts / cm with a maximum discharge rate of 3 - 200 kg per minute and a comb erv ο ium en of 0.5-5 cm * 'on.

When performing the inventive method the components are separated from a storage container under pressure, preferably using multi-cylinder piston pumps led to the mixing chamber.

The process is carried out at a temperature at which the components are liquid and their viscosity is preferably less than 2000 cP; Temperatures in the range from 0 to 150 ^° C. are preferred. Prepolymers that 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 are only required at elevated temperature Have viscosity, storage tanks, pump units and lines are heated.

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Prepolymerl-l.ösuri.ii) and liquid phase can of course be added different temperatures are conveyed and mixed. The increased temperature accelerates !, naturally the one before, during or n: u.h the mixture i »/ w. Emulsification subsequent polyaddition reaction.

It has been found to be advantageous for mixing by counter siromirjection that emulsifiers or auxiliaries which increase the emulsifiability of the prepolymer (Losuna) in the liquid phase are added to the liquid phase. These are compounds that are used to produce oil -in-water-emulsions and water-in-oil emulsions are used as well as anion-active, kauonakn'vt, ampholytic and non-ionic compounds, as they are in Römpps Chemie-Lexikon, 7th edition, Frackh 'see Verlagshandlung, W. Keller & Co., Stuttgart, 1973, pages 1009-11) 13, as well as in Kirk-Othmer Vol. B, pages 117-154 and Ul! Mann Hd. 1, pages 717-724.

Together with or instead of the emulsifiers, so-called laminators (cf. Belgian patent 718 029) or ionic or hydrophilic polyurethanes, which are optionally present dispersed in water, can be used. Such polyurethane dispersions are for example in German Offenlegungsschriften 1 495 745, 1 495 847 and 1,770,066 or U.S. Patent 3,479,310.

The emulsifiers or additives are in the liquid phase in one Contains a concentration of 0.01 to 40% by weight, with is preferred a concentration of 0.1-10 wt.% worked.

The molar amount of chain extender generally corresponds to the amount of NCO groups present; the molar ratio of NCO: [ll]

r ι Κ

is preferably 1 {{.Ely = molar concentration of liCO-reactive

Groups). You can also use smaller amounts of chain extender

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use (N'CO: / ίί /> 1), approximately up to the ratio NCO: f ^ J _K ~ 1 » ' ^ύ > preferably 1.5, then the molecular weight of the polyurethanes or lOlyurethanursfofte is lower and thus their melting point is lower.

The /, ", gaue nasty chain lengthener can take place before, during or after the mixing of the! YepulymeH solution) and the liquid phase to dissolve or emulsify in the aqueous phase In all cases, the etra-ene material from the mixed container is used to carry out the chain-lengthening reaction and, if the components are mixed at elevated temperature, stirred while cooling to room temperature

Is worked with the help of solvents, their presence undesirable in the finished dispersion or suspension is so is. it is advisable to keep the organic solvent at 20-100.degree preferably 40-70 ° C., to be distilled off at reduced pressure. Another method is the solvent with air or nitrogen blown out.

The prepolymers used in the process according to the invention preferably have an NGO content of 1-15 percent by weight, in particular 1-5 percent by weight . The prepolymers are processed either in bulk or in the form of solutions in the solvents already mentioned above , the solutions having a solids content of at least 50, preferably at least 70 percent by weight. When working without a solvent can

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-preferably the desired viscosity range of 50-2000, in particular 300-1500 cP by heating the prepolymer to a maximum of 150 G ⁰ is preferably set to 80 to 130 ⁰ C. In the process according to the invention, the amount of water is chosen so that 15-55, preferably 20-40 percent aqueous dispersions are obtained.

Suspensions produced according to the inventive method can be used to obtain polyurethane (urea) powders be. The powder is obtained by removing the liquid phase from the solid suspension phase, for. B. by decanting, filtering, centrifuging separated off and the solid obtained in this way is dried in a suitable manner, if appropriate with mechanical agitation, if appropriate under reduced Printing, possibly with the addition of auxiliaries that accelerate drying. Depending on the size of the polyurethane (urea) particles in the suspension one finest to coarse powder.

The products of the process are in particular as aqueous dispersions also for coating and impregnating paper, [textiles, leather,

Nonwovens, wood and metals and as adhesion promoters, adhesives, binders or Laminating agent suitable. Furthermore, dipping articles can be made using the latex foam whipping process by adding electrolytes Coagulates are obtained, which are further processed in the usual way on the mixing roller.

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

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The dispersions can generally be converted directly into insulating films ; Plastic coverings. Au. «Dispersions unvenii'izi ¹ ] · Polynrei'iane can in the presence of polyfunctional, \ ernet ;! acting substances like i ^ orinaldeliy · '. or formaldehyde-releasing or how ormaldehyde refi ^ ie fc tidea substances such as carbamide or plienolli resin, disguised polyisocyanates, polyepoxides are negated.

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Example 1: * (jrt.

Iin the following example, an injection Misehaggregat is used, as in "Kunststoff-Handbuch", Volume VII, "Polyurethane", Carl-Hanser-Verlag, Munich (1966), pages is described in principle in 130 ff.. The unit has an I-iischkaini-aervolunien of 0.5 crp /, it has a discharge capacity of a maximum of 15 kg / Μη, a machine of this type is commercially available under the designation HK 15 ('naeciiLnenfa.br ± k Hennecke) .

A prepolymer with a KCO content of 3.1 percent by weight, produced from 1.8 mol of hexamethylene diisocyanate and 1 Hol of a mixed polyester of adipic acid, 1,6-hexanediol, and ueopentyl glycol with an average molecular weight of 1700, is applied over this HK 1 b at a nozzle pressure of 200 atmospheres. with a 6.7 following solution of an ethoxylated Honylphenol (30 Hol ethylene oxide / mol nonylphenol) in water, which was also compressed to a pressure of 200 atmospheres *) "?" mixed. The Prepolyuer is at a lemperatur of 110 - 12O processed ° C and a viscosity of about 1450 cps, the aqueous solution having a temperature of 25 ⁰ C and a viscosity of 2-3 cP. The components are fed into the mixing chamber in a weight ratio of prepolymer: aqueous solution = 1: 2.

The mixture is after discharging with stirring at 90% of the calculated NCO content equivalent amount of a 1 η solution of N- (2-aminoethyl) -2-aminoäthansulfonsaurem Sodium prolonged in water. After a few hours of stirring while cooling to room temperature and Thinning with water gives a finely divided, stable dispersion with a solids content of 17.5%.

* The selected nozzle diameters naturally correspond to the specified pressure, viscosity and quantity ratios.

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A repolymer with 3.1 '/ NGO, produced from 1.8 mol of hexamethylene diisocyanate and 1 mol of a mixed polyester of adipic acid, 1,6-hexanediol, neopentyl glycol with an average molecular weight of 1700, with a 5' / 'also strength to 200 atm compressed anionic aqueous dispersion of a polyurethane urea "mixed the prepolymer has a temperature of 110 -. 120 ⁰ C, a viscosity of about 1450 cps, the aqueous dispersion has a temperature of 25 ⁰ O and line viscosity of The components are conveyed into the mixing chamber in a weight ratio of prepolymer: aqueous dispersion = 1: 2.

After discharging, with stirring, the mixture is mixed with 80% of the amount of a 1 η solution equivalent to the calculated NCO content extended by N- (2-aminoethyl) -2-aminoäthansulfon acid sodium in water. After a few hours of stirring while cooling at room temperature and diluting with water, a finely divided, redispersible suspension with a solids content of 27.4%.

* The anionic polyurethane dispersion was prepared according to the teaching of American patent specification 3,479,310 from 209 pounds of an adipic acid-hexanediol-neopentyl glycol disehester (average molecular weight 1700), 38 g 1,6-diisocyanatohexane, 13.8 g of a 43 ', Sigen aqueous solution of if- (2-aminoethyl) -2-aminoethanesulfonic acid liatric salt, 1.9 g of 1,2-diaminoethane and 530 g of water. The dispersion was then diluted with water to a solids content of 5%.

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Example 3:

I fro a UK 15 mis. 3 metering units and a 3-component mixer, a prepolymer with 2, H "fo NCX>, produced from 1.8 moles of Ifexameihylenendiisoeyanat and 1 mole of a mixed polyester of adipic acid, hexanediol-1, 6, neopentyl glycol with / 200 atm voru mean molecular weight 1700, a 5 ^ solution of the above ethoxylated nonylphenol in water and an aqueous solution of IT- (2-aminoethyl) -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 110-12O ⁰ C, a viscosity of approx. 145OcP, the aqueous solution of the chain extender has a [temperature of 25 ⁰ C and a viscosity of about 1 cP, and the aqueous solution of ethoxylated nonylphenol having a! Temperature of 25 ⁰ C and a viscosity of about 2.5 cP.

The components are in the prepolymer: solution by weight ratio Chain extender = 1: 0.25 and prepolymer: solution of the ethoxylated Nonylphenols · - 1: 1, 2 dosed into the mixing chamber, with the concentration of the extender in the aqueous solution is chosen so that it is 80% equivalent to the NCO content of the prepolymer.

After discharging, the mixture is stirred for a few hours while cooling to room temperature and passed through a sieve filtered from 0.1 mm lorry width. The ITiltrate forms a finely divided, redispersible suspension from the residual substance content 31.4, ^.

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Example 4:

Via an HK 100 (this machine corresponds to the above HK 15 with the difference that the chamber volume is 1 cm and the maximum discharge rate is 100 kg / min. total mixture), a prepolymer with 3.2 % NCO- , prepared from 1.8 mol of hexamethylene diisocyanate and 1 mol of a mixed polyester of adipic acid, 1,6-hexanediol, neopentyl glycol with an average molecular weight of 1700, mixed with a 3% solution of the above ethoxylated honylphenol in water. The prepolymer has a temperature from 95 to 115 ° 0, a viscosity of about 165OcP, the aqueous solution has a temperature of 25 ⁰ C and a viscosity of about 2 cP. The components are fed into the mixing chamber in a prepolymer: aqueous solution weight ratio of 2: 3.

Immediately after mixing, 80% of theory is used for the Total amount of isocyanate chain-extended, with a 40% aqueous Solution of N- (2-aminoethyl) -2-aminoäthansulfonsaurem sodium used will. A dispersion of 40% solids is obtained is diluted to 30% solids with water and is stable. The dispersion is finely divided, the particle diameter is approx. 230

Example 5:

3e
A 70% acetone solution of a prepolymer with an NCO content of 1.6% with a 1% strength is dispensed via an HK 15 with an initial pressure of 80 atmospheres

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mixed aqueous solution of a älhoxylierter Nouylphenol. The prepolymer was made from 1, B mol of hexamelhylene diisocyanal and 1 mol of oinos polyester from adipic acid and mutanediol-1,4 with an average molecular weight of 2250. The prepolymer solution has. a temperature of 45-50 ° C., a viscosity of approx. 400 cP, the aqueous solution has a temperature of 25 ^° C. and a viscosity of approx. 1 et. The components are injected into the mixing chamber in a weight ratio of prepolymer solution: aqueous solution = 1: 1.8.

After discharge, the mixture is extended with stirring with 85% of the amount of a 1 η propylenediamine solution in water equivalent to the calculated NOO-CehnH. After a few hours of stirring while cooling to room temperature, the resulting suspension is freed from water and acetone by decanting and the residue is dried in a vacuum of 12 torr over a desiccant. The thermoplastic polyurethane-urea powder thus obtained has a high fines content and has a Schiae laber calibration 140-160 ⁰ G.

Example 6;

Via an HK 100, 100 air nozzles are used to pre-press an acetone Prepolymer solution and a 10.7% solution of 1,2-propylenediamine mixed together in water.

The acetone prepolymer solution is prepared as follows:

9,500 g of a hexanediol polycarbonate with a molecular weight of 1870 are at 120 C / 15 Torr dehydrated. At 106 ° C., 1.510 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 N-methyldiethanolamine dissolved in 750 g of acetone, lasts about 3 hours.

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at 60 C and diluted with a further 2,000 g of acetone. The next day, the mixture is heated to 55 ° C. and quaternized with 6.2 ml of dimethyl sulfate dissolved in 8.420 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%

r ^ ²⁵ = 182 cp

n ⁵⁰ = 125 cp

The temperature of the components is 25 C. The components are in the weight ratio prepolymer solution: diamine solution as 1: 1 in the Mixing chamber promoted. A sedimenting suspension is discharged which, after decanting and drying, forms a thermoplastic polyurethane urea powder with a melting point of 140-146 ° C.

Example 7:

Repetition of example β, the aqueous diamine solution being 6% based on total solids of a 15%, cationic polyurethane dispersion can be added. The polyurethane urea powder obtained from the batch is somewhat more finely divided with the same melting point. The mean particle diameter is 43 u.

* The cationic polyurethane dispersion was prepared according to the teaching of American patent specification 3,479,310 from 9700 g (7 mol) of a tetraethylene glycol-1,6-hexanediol polycarbonate (molar ratio 5: 2), 1800 g 1,6-diisocyanatohexane, 214 g II -Methyl diethanolamine, 214 g dimethyl sulfate, 25 g hydrazine hydrate, 58 g 1,6-diaminohexane, 400 g 20% phosphoric acid, 200 g 30% formaldehyde and 24,000 g water. The dispersion was then diluted to 15 ° / ° pesticide with water. The mean particle size is 144 μm.

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Claims (6)

Patent claims: " Process for the continuous production of aqueous Polyurethane dispersions by mixing a liquid or one dissolved in an organic solvent prepolymers containing terminal isocyanate groups with water and optionally chain extenders with at least two isocyanate-reactive groups Groups, optionally with the use of emulsifiers and / or other auxiliaries, characterized in that that the mixing of the starting componentη takes place according to the countercurrent injection process. 2. The method according to claim 1, characterized in that that prepolymers or prepolymer solutions are used whose viscosity is between 50 and 2000 cP. 3. The method according to claim 1 to 2, characterized in that one uses prepolymers containing ionic groups. 4. The method according to claim 1 to 3, characterized in that chain extenders containing ionic groups are used begins. 5. The method according to claim 1 to 4 »characterized in that the components are mixed in a countercurrent injection apparatus, at least one of the components being compressed to a pre-pressure of 20-500 atm and through a nozzle with the or the remaining components in mixed in a mixing chamber with a volume of 0.5-5 cm. Le A 15 220 - 27 - 509811/0950 23U135 6. Use of the accessible according to claims 1 to 5 Dispersions for the production of polyurethane powders. Le A 15 220 - 28 - 509811/0950