EP0000381B1 - Process for the preparation of isocyanate polyaddition products containing lateral hydroxyl groups and products obtained by this process - Google Patents

Description

The present invention relates to a new process for the preparation of new isocyanate polyaddition products having pendant hydroxyl groups and to the compounds obtainable by this process.

The process according to the invention is based on the principle of reacting reactive systems containing isocyanate groups and oxazolidine groups with water, the chain extension reaction taking place essentially with the formation of urea groups from the isocyanate groups and the amino groups hydrolytically released from the oxazolidines, while the hydrolytic cleavage of the oxazolidine groups also takes place comparatively inert hydroxyl groups do not participate in the reaction and are present laterally in the process products.

The principle of crosslinking reactive systems containing isocyanate groups and oxazolidine groups under the influence of moisture is already known from numerous publications (cf., for example, DE-A 1 952 091.1, 952 092.2018 233, 2 446 438.2 458 588 and US ―A 3 661 923.3 743 626, 3 864 335 or 4 002 601). The compositions of these publications are generally systems which are stable in the absence of moisture and have oxazolidines and isocyanates which, under the influence of atmospheric moisture, i.e. react under the influence of traces of water to form high-molecular, cross-linked structures. Due to the slow entry of water in the form of atmospheric humidity, both the amino groups and the hydroxyl groups of the hydrolytically split oxazolidine react with the isocyanate groups. This therefore leads less to chain extension reactions than to real crosslinking of the polyisocyanate component, with virtually no pendant hydroxyl groups being present in the resulting process products. Any references to the method according to the invention described below cannot be found in the publications mentioned.

• a) im wesentlichen lineare Präpolymere, welche endständig sowohl Isocyanatgruppen als auch Oxazolidingruppen oder
• b) ein im wesentlichen lineare NCO-Präpolymere und Bis-oxazolidine aufweisendes Gemisch durch Vermischen mit Wasser kettenverlängert, wobei die Wassermenge so bemessen wird, daß pro Mol an im Reaktionsgemisch vorliegenden Oxazolidingruppen mindestens 1 Mol Wasser vorliegt.

The present invention relates to a process for the preparation of essentially linear isocyanate polyadducts with pendant hydroxyl groups by reacting reactive systems containing free isocyanate groups and oxazolidine groups with water, characterized in that

• a) essentially linear prepolymers which are terminal both isocyanate groups and oxazolidine groups or
• b) a mixture comprising essentially linear NCO prepolymers and bis-oxazolidines is chain-extended by mixing with water, the amount of water being such that at least 1 mol of water is present per mol of oxazolidine groups present in the reaction mixture.

The present invention in particular also relates to an embodiment of this method in which prepolymers which are hydrophilically modified and / or contain an external emulsifier and a preponderant excess of water with respect to the chain extension reaction are used, so that an aqueous dispersion or solution of the polyadducts is obtained directly.

The process according to the invention for the first time opens up a possibility of producing predominantly linear polyurethanes which are therefore soluble in common solvents and which have pendant hydroxyl groups and are therefore accessible to a subsequent crosslinking reaction, for example with organic polyisocyanates. Because of their linear structure, the process products according to the invention can be converted without difficulty into aqueous dispersions or solutions, with the simultaneous incorporation of hydrophilic groups and / or with the use of external emulsifiers, from which it is then also possible to subsequently produce simply crosslinkable fabrics.

Starting materials for the process according to the invention are essentially linear prepolymers which have a statistical average of 1.8 to 2.2, preferably 2, terminal isocyanate groups and which generally have an average molecular weight of 500 to 10,000, preferably 800 to 4,000.

The NCO prepolymers are prepared by known methods of polyurethane chemistry by reacting excess amounts of organic polyisocyanates, preferably diisocyanates, with suitable, preferably difunctional, compounds having groups which are reactive toward isocyanate groups. Starting materials for the preparation of the NCO prepolymers are accordingly.

wobei Q für einen aliphatischen Kohlenwasserstoffrest mit 4 bis 12 Kohlenstoffatomen, einen cycloaliphatischen Kohlenwasserstoffrest mit 6 bis 15 Kohlenstoffatomen, einen aromatischen Kohlenwasserstoffrest mit 6 bis 15 Kohlenstoffatomen oder einen araliphatischen Kohlenwasserstoffrest mit 7 bis 15 Kohlenstoffatomen bedeutet. Beispiele derartiger bevorzugt einzusetzender Diisocyanate sind Tetramethylendiisocyanat, Hexamethylendiisocyanat, Dodecamethylendiisocyanat. 1,4 - Diisocyanato - cyclohexan, 1 - Isocyanato - 3,3,5 - trimethyl - 5 - isocyanatomethylcyclohexan, 4,4' - Diisocyanatodicyclohexylmethan, 4,4' - Dilsocyanato - -dicyclohexylpropan - (2,2), 1,4 - Diisocyanatobenzol, 2,4 - Diisocyanatotoluol, 2,6 - Diisocyanatotoluol, 4,4' - Diisocyanatodiphenylmethan, 4,4' - Diisocyanato - diphenylpropan - (2,2), p - Xylylen - diisocyanat oder α, a, a', α' - Tetramethyl - m - oder p - xylylen - diisocyanat, sowie aus diesen Verbindungen bestehende Gemische.1. any organic polyisocyanates, preferably diisocyanates of the formula

wherein Q represents an aliphatic hydrocarbon group having 4 to 12 carbon atoms, a cycloaliphatic hydrocarbon group having 6 to 15 carbon atoms, an aromatic hydrocarbon group having 6 to 15 carbon atoms or an araliphatic hydrocarbon group having 7 to 15 carbon atoms. Examples of such preferred diisocyanates are Tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate. 1,4 - diisocyanato - cyclohexane, 1 - isocyanato - 3,3,5 - trimethyl - 5 - isocyanatomethylcyclohexane, 4,4 '- diisocyanatodicyclohexylmethane, 4,4' - dilsocyanato - dicyclohexylpropane - (2,2), 1,4 - diisocyanatobenzene, 2,4 - diisocyanatotoluene, 2,6 - diisocyanatotoluene, 4,4 '- diisocyanatodiphenylmethane, 4,4' - diisocyanato - diphenylpropane - (2,2), p - xylylene - diisocyanate or α, a, a ', α '- Tetramethyl - m - or p - xylylene diisocyanate, as well as mixtures consisting of these compounds.

It is of course also possible to use the polyfunctional polyisocyanates known per se in polyurethane chemistry, or else modified polyisocyanates containing, for example, carbodiimide groups, allophanate groups, isocyanurate groups, urethane groups and / or biuret groups.

2. Any organic compounds with at least two groups that are reactive toward isocyanate groups, in particular a total of two amino groups, thiol groups, carboxyl groups and / or hydroxyl-containing organic compounds of the molecular weight range 62-10,000, preferably 1,000 to 6,000. The corresponding dihydroxy compounds are preferably used. The use of tri-functional or higher-functional compounds in the sense of the isocyanate polyaddition reaction in small proportions to achieve a certain degree of branching is possible, as is the possible use of tri- or higher-functional polyisocyanates already mentioned for the same purpose.

• Bernsteinsäure, Adipinsäure, Korksäure, Azelainsäure, Sebacinsäure, Phthalsäure, Isophthalsäure, Trimellitsäure, Phthalsäureanhydrid, Tetrahydrophthalsäureanhydrid, Hexahydrophthalsäureanhydrid, Tetrachlorphthalsäureanhydrid, Endomethylentetrahydro,phthalsäureanhydrid, Glutarsäureanhydrid, Maleinsäure, Maleinsäureanhydrid, Fumarsäure, dimere und trimere Fettsäuren wie Ölsäure, gegebenenfalls in Mischung mit monomeren Fettsäuren, Terephthalsäuredimethylester, Terephthalsäure - bis - glykolester. Als mehrwertige Alkohole kommen z.B. Äthylenglykol, Propylenglykol - (1,2) und - (1,3), Butylenglykol - (1,4) und - (2,3), Hexandiol - (1,6), Octandiol - (1,8), Neopentylglykol - Cyclohexandimethanol - (1,4 - Bis - hydroxymethyicyclohexan), 2 - Methyl - 1,3 - propandiol, Glycerin, Trimethylolpropan, Hexantriol - (1,2,6), Butantriol - (1,2,4), Trimethyloläthan, Pentaerythrit, Chinit, Mannit und Sorbit, Methylglykosid, ferner Diäthylenglykol, Triäthylenglykol, Tetraäthylenglykol, Polyäthylenglykole, Dipropylenglykol, Polypropylenglykole, Dibutylenglykol und Polybutylenglykole in Frage. Die Polyester können anteilig endständige Carboxylgruppen aufweisen. Auch Polyester aus Lactonen, z.B. _E-Caprolacton oder Hydroxycarbonsäuren, z.B. co-Hydroxycapronsäure, sind einsetzbar.

Hydroxyl compounds which are preferably used are the hydroxypolyesters, hydroxypolyethers, hydroxypolythioethers, hydroxypolyacetals, hydroxypolycarbonates and / or hydroxypolyesteramides known per se in polyurethane chemistry. The polyesters containing hydroxyl groups are, for example, reaction 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 anhydrides or corresponding polycarboxylic esters of lower alcohols or mixtures thereof can also be used to produce the polyesters. The polycarboxylic acids can be aliphatic, cycloaliphatic, aromatic and / or heterocyclic in nature and optionally substituted, for example by halogen atoms, and / or unsaturated. Examples include:

• Succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, trimellitic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrachlorophthalic anhydride, oleic acid, fatty acid maleinic acid, phthalic anhydride, phthalic acid fatty acid mixture, maleic acid, fatty acid malic acid, Dimethyl terephthalate, bis-glycol ester. Examples of polyhydric alcohols include ethylene glycol, propylene glycol - (1,2) and - (1,3), butylene glycol - (1,4) and - (2,3), hexanediol - (1,6), octanediol - (1, 8), neopentyl glycol - cyclohexanedimethanol - (1,4 - bis - hydroxymethyicyclohexane), 2 - methyl - 1,3 - propanediol, glycerin, trimethylolpropane, hexanetriol - (1,2,6), butanetriol - (1,2,4) , Trimethylolethane, pentaerythritol, quinite, mannitol and sorbitol, methylglycoside, also diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycols, dipropylene glycol, polypropylene glycols, dibutylene glycol and polybutylene glycols in question. The polyesters may have a proportion of terminal carboxyl groups. Polyesters of lactones, for example _E- caprolactone or hydroxycarboxylic acids, for example co-hydroxycaproic acid, can also be used.

The polyethers which are preferred according to the invention and preferably have two hydroxyl groups are those of the type known per se and are, for example, polymerized by themselves with epoxides such as ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide or epichlorohydrin, for example in the presence of BF ₃ , or by addition of these epoxides, optionally in a mixture or in succession, to starting components with reactive hydrogen atoms such as alcohols and amines, for example water, ethylene glycol, propylene glycol - (1,3) or - (1,2), 4,4 '- dihydroxy-diphenylpropane, Aniline.

Polyethers modified by vinyl polymers, e.g. by polymerization of styrene or acrylonitrile in the presence of polyethers (American patents 3,383,351, 3,304,273, 3,523,093, 3,110,695, German patent 1,152,536) are also suitable. The proportionally higher-functionality polyethers to be used, if appropriate, are formed in an analogous manner by known alkoxylation of higher-functionality starter molecules, e.g. Ammonia, ethanolamine, ethylenediamine or sucrose.

Among the polythioethers, the condensation products of thiodiglycol with itself and / or with other glycols, dicarboxylic acids, formaldehyde, aminocarboxylic acids or amino alcohols should be mentioned in particular. Depending on the CO components, the products are polythio ether, polythio ether ester, polythio ether ester amide.

As polyacetals e.g. the compounds which can be prepared from glycols, such as diethylene glycol, triethylene glycol, 4,4'-diethoxy-diphenyldimethylmethane, hexanediol and formaldehyde. Polyacetals suitable according to the invention can also be prepared by polymerizing cyclic acetals.

Suitable polycarbonates containing hydroxyl groups are those of the type known per se. which, for example, by reacting diols such as propanediol - (1,3), butanediol - (1,4) and / or Hexanediol - (1,6), diethylene glycol, triethylene glycol, tetraethylene glycol with diaryl carbonates, for example diphenyl carbonate, or phosgene, can be prepared.

The polyester amides and polyamides include e.g. the predominantly linear condensates obtained from polyvalent saturated and unsaturated carboxylic acids or their anhydrides and polyvalent saturated and unsaturated amino alcohols, diamines, polyamines and their mixtures. Polyhydroxyl compounds already containing urethane or urea groups can also be used.

Low molecular weight polyols can also be used, e.g. Ethanediol, 1,2-and 1,3-propanediol, 1,4-and 1,3-butanediol, pentanediols, hexanediols, trimethylolpropane, hexanetriols, glycerol and pentaerythritol.

Representatives of the polyisocyanate and hydroxyl compounds mentioned to be used in the process according to the invention are e.g. 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 11, 1964, Pages 6-6 and 198-199, as well as in the plastic manual, volume VII, Vieweg-Höchtlen, Carl-Hanser-Verlag, Munich, 1966, e.g. on pages 45 to 71, described.

If in the inventive method according to the above. In a particular embodiment, hydrophilically modified prepolymers are to be used, they are produced by known processes of the prior art, for example in accordance with DT-OSs 1 495 745, 1 495 847, 2 446 440, 2 340 · 512, US Pat 310, GB-PS'en 1 158 088 or 1 076 688 described methods. This means that in the preparation of the prepolymers, in addition to the starting materials already mentioned by way of example, chemically fixed hydrophilic groups, preferably in the sense of the isocyanate addition reaction, having mono- and in particular difunctional structural components of those exemplified in the abovementioned. References related to the preparation of aqueous polyurethane dispersions or solutions, i.e. for example, diisocyanates, diamines or dihydroxy compounds or diisocyanates or glycols containing ionic or potential ionic groups or polyethylene oxide units can also be used.

The preferred hydrophilically modified structural components include in particular the sulfonate group-containing aliphatic diols according to DE-A 2 446 440, the cationic or also anionic internal emulsifiers which can be incorporated according to German patent application P 26 51 506.0 and also the monofunctional incorporable polyethers described in this patent application.

In the preparation of the NCO prepolymers according to known principles of the prior art, the reactants are generally used in such proportions that a ratio of isocyanate groups to hydrogen atoms reactive towards NCO, preferably from hydroxyl groups, from 1.05 to 10, preferably from 1.1 to 3 correspond.

The order in which the individual reactants are added is largely arbitrary. You can either mix the hydroxyl compounds and add the polyisocyanate, or you can gradually add the mixture of hydroxyl compounds or the individual hydroxyl compounds to the polyisocyanate component.

The NCO prepolymers are preferably produced in the melt at 30 to 190 ° C., preferably at 50 to 120 ° C. The prepolymers could of course also be produced in the presence of organic solvents.

Suitable solvents, e.g. in an amount up to 25% by weight, based on the solid, could be used e.g. Acetone, methyl ethyl ketone, ethyl acetate, dimethylformamide or cyclohexanone.

• a) eine mittlere NCO-Funktionalität von 1,8 bis 2,2, vorzugsweise 2,
• b) einen Gehalt an kationischen oder anionischen eingebauten Gruppen von 0 bis 100, vorzugsweise 0,1 bis 100 und insbesondere 0,5 bis 50 Milli-Äquivalent pro 100 g Feststoff,
• c) einen Gehalt an seitenständig, endständig und/oder innerhalb der Hauptkette eingebauten, innerhalb eines Polyäthersegments vorliegenden Äthylenoxid-Einheiten von 0 bis 30, vorzugsweise 0,5 bis 30 und insbesondere 1 bis 20 Gew.-%, bezogen auf das Gesamtgewicht des Präpolymeren und
• d) ein mittleres Molekulargewicht von 500 bis 10.000, vorzugsweise 800 bis 4.000 aufweisen.

The nature and proportions of the starting materials used in the preparation of the NCO prepolymers are preferably chosen so that the NCO prepolymers

• a) an average NCO functionality of 1.8 to 2.2, preferably 2,
• b) a content of cationic or anionic built-in groups of 0 to 100, preferably 0.1 to 100 and in particular 0.5 to 50 milliequivalents per 100 g of solid,
• c) a content of laterally, terminally and / or within the main chain, within a polyether segment present ethylene oxide units of 0 to 30, preferably 0.5 to 30 and in particular 1 to 20 wt .-%, based on the total weight of the prepolymer and
• d) have an average molecular weight of 500 to 10,000, preferably 800 to 4,000.

As already stated, the preferred NCO prepolymers include those which are either ionic groups of the type mentioned under b), ie in particular -COO-, -S03 or = N ⁺ =, or nonionic groups of the type mentioned under c) or both have ionic as well as nonionic groups of the type mentioned. However, it is also possible to use NCO prepolymers in the process according to the invention, in the production of which none of the hydrophilic structural components mentioned have been used, in which the content of the groups mentioned above under b) or c) is therefore 0.

If such NCO prepolymers are used, which, moreover, have the properties mentioned under a) and d) above, the preparation of aqueous dispersions or solutions of the process products according to the invention is only effective when carrying out the process according to the invention possible if external emulsifiers are also used. Suitable such emulsifiers are described, for example, by R. Heusch in "Emulsions", Ullmann, Volume 10, pages 449-473, Weinheim 1975. Both ionic emulsifiers such as alkali and ammonium salts of long-chain fatty acids or long-chain aryl (alkyl) sulfonic acids are suitable, as are nonionic emulsifiers such as ethoxylated alkylbenzenes with an average molecular weight of 500 to 10,000.

These external emulsifiers are thoroughly mixed with the NCO prepolymers before the process according to the invention is carried out. They are generally used in amounts of 1 to 30, preferably 5 to 20,% by weight, based on the weight of the NCO prepolymer. It is also possible to increase the hydrophilicity of the hydrophilic modified NCO prepolymers by using such external emulsifiers, although this is generally not necessary.

As already explained, the incorporation of hydrophilic groups or the use of external emulsifiers is not absolutely necessary when carrying out the process according to the invention, but generally only takes place if the process products according to the invention are to be obtained in the form of aqueous dispersions or solutions. It is therefore entirely conceivable to carry out the process according to the invention, for example in the solvent mentioned above by way of example, in which case solutions of the process products according to the invention are obtained in these solvents.

aufweisen, wobei

• R, und R₂ für gleiche oder verschiedene Reste stehen und Wasserstoff, aliphatische Kohlenwasserstoffreste mit 1-4 Kohlenstoffatomen, cycloaliphatische Kohlenwasserstoffreste mit 5-7 Kohlenstoffatomen oder aromatische Kohlenwasserstoffreste mit 6-10 Kohlenstoffatomen bedeuten bzw. zusammen mit dem Ring-Kohlenstoffatom gemeinsam einen 5- oder 6-gliedrigen cycloaliphatischen Kohlenwasserstoff-Ring bilden können,
• X für einen Rest der Formel
  
  steht, wobei R₃ und R₄ für gleiche oder verschiedene Reste stehen und C1-C4-Alkylreste, vorzugsweise jedoch Wasserstoff bedeuten und m 2 oder 3 bedeuten,
• Y für einen Rest der Formel
  
  steht, in welcher R₃ und R₄ die bereits genannte Bedeutung haben und n für eine ganze Zahl von 2 bis 6 steht.

The above-mentioned NCO prepolymers with 1.8-2.2, preferably 2, terminal isocyanate groups are preferably used in the process according to the invention in a mixture with bisoxazolidines. "Bisoxazolidines" are to be understood here as meaning any organic compounds which have 2 oxazolidine groups which form a hydroxyl and a secondary amino group under the influence of water and are otherwise inert under the conditions of the process according to the invention. The preferred bisoxazolidines include those which have 2 groups of the formula

have, where

• R and R _{2 represent} identical or different radicals and represent hydrogen, aliphatic hydrocarbon radicals with 1-4 carbon atoms, cycloaliphatic hydrocarbon radicals with 5-7 carbon atoms or aromatic hydrocarbon radicals with 6-10 carbon atoms or together with the ring carbon atom together represent a 5- or can form 6-membered cycloaliphatic hydrocarbon ring,
• X for a residue of the formula
  
  where R ₃ and R _{4 are the} same or different radicals and are C1-C4-alkyl radicals, but are preferably hydrogen and m are 2 or 3,
• Y for a residue of the formula
  
  stands in which R ₃ and R _{4 have} the meaning already mentioned and n stands for an integer from 2 to 6.

verknüpft sind, wobei

• A und A' für gleiche oder verschiedene Reste stehen und ―COO― oder ―OCO―NH― bedeuten und
• Z für einen zweiwertigen aliphatischen Kohlenwasserstoffrest mit 2-14 Kohlenstoffatomen, einen zweiwertigen cycloaliphatischen Kohlenwasserstoffrest mit 5-14 Kohlenstoffatomen oder einen Arylenrest mit 6-15 Kohlenstoffatomen steht.

The particularly preferred bisoxazolidines include those in which 2 radicals of the above formula have a divalent radical of the formula

are linked, whereby

• A and A 'represent the same or different radicals and mean ―COO― or ―OCO ― NH― and
• Z represents a divalent aliphatic hydrocarbon radical with 2-14 carbon atoms, a divalent cycloaliphatic hydrocarbon radical with 5-14 carbon atoms or an arylene radical with 6-15 carbon atoms.

In the process according to the invention, either mixtures of the exemplified NCO prepolymers with the exemplified bisoxazolidines or predominantly linear isocanate groups and prepolymers containing oxazolidine groups are used.

in welcher

• R_1' R₂, X und Y die bereits genannte Bedeutung haben, hergestellt werden.

These latter prepolymers can be obtained in a simple manner by reacting the predominantly difunctional NCO prepolymers mentioned above with hydroxyl-containing oxazolidines of the formula

in which

• R _{1 '} R ₂ , X and Y have the meaning already mentioned, are produced.

In this preparation of the prepolymers containing isocyanate groups and oxazolidines, the reactants are preferably used in proportions such that 0.37-0.53, preferably 0.4-0.51 mol, hydroxyl groups of the hydroxyoxyzolidine are present in each mole of isocyanate groups in the NCO prepolymer. Reaction mixtures are obtained on these which have about 0.6-1.1, preferably about 0.65-1.05, oxazoline groups per remaining isocyanate group. Since the monohydroxyoxazolidines are monofunctional compounds, there is no appreciable increase in molecular size in this reaction. The reaction products, like the NCO prepolymers used as starting materials, are therefore essentially linear compounds.

Both the hydroxyoxazolidines and the bisoxazolidines mentioned are compounds known from the literature (see, for example, the references mentioned at the beginning with regard to the moisture-curing oxazolidine compositions of the prior art). Bisoxazolidines or hydroxyoxazolidines to be used with particular preference are the corresponding compounds mentioned in US Pat. No. 4,002,601 and DE-A 2,446,438.

eignen sich insbesondere nachstehend aufgeführte Aldehyde und Ketone:

• Formaldehyd, Acetaldehyd, Propionaldehyd, Butyraldehyd, Isobutyraldehyd, Benzaldehyd, Tetrahydrobenzaldehyd, Aceton, Methyläthylketon, Methylpropylketon, Methylisopropylketon, Diäthylketon, Methylbutylketon, Methylisobutylketon, Methyl-t-butylketon, Diisobutylketon, Cyclopentanon und Cyclohexanon. Bevorzugt einzusetzende Carbonylverbindungen sind entsprechend der vorstehenden Definition der bevorzugten Reste R₁ und R₂ Formaldehyd sowie die genannten aliphatischen Aldehyde bzw. Ketone.

The N-hydroxyalkyl oxazolidines are prepared by methods known from the literature, a ketone or an aldehyde being condensed with a bis- (hydroxyalkyl) amine with cyclizing dehydration, and the water of reaction being removed azeotropically by an inert entrainer or by the excess carbonyl compound becomes.
As carbonyl compounds

Aldehydes and ketones listed below are particularly suitable:

• Formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, benzaldehyde, tetrahydrobenzaldehyde, acetone, methyl ethyl ketone, methyl propyl ketone, methyl isopropyl ketone, diethyl ketone, methyl butyl ketone, methyl isobutyl ketone, methyl t-butyl ketone and cyclohexo ketone, diisobutyl ketone. According to the above definition of the preferred radicals R ₁ and R ₂ , carbonyl compounds to be used with preference are formaldehyde and the aliphatic aldehydes or ketones mentioned.

eignen sich besonders Bis-(2-hydroxyäthyl)-amin und Bis-(2-hydroxypropyl)-amin. Im Prinzip ebenso geeignet sind jedoch auch beispielsweise Bis-(2-hydroxybutyt)-amin, Bis-(2-hydroxyhexyl)-amin, Bis-(3-hydroxyhexyl)-amin, oder N-(2-hydroxypropyl)-N-(6-hydroxyhexyl)-amin.As bis (hydroxyalkyl) amines

Bis- (2-hydroxyethyl) amine and bis- (2-hydroxypropyl) amine are particularly suitable. In principle, however, bis- (2-hydroxybutyt) amine, bis- (2-hydroxyhexyl) amine, bis- (3-hydroxyhexyl) amine, or N- (2-hydroxypropyl) -N- ( 6-hydroxyhexyl) amine.

(in der Z die oben angegebene Bedeutung besitzt) z.B. Hexamethylendiisocyanat. 3,3,5-Trimethyl-5-isocyanatomethyl-cyclohexylisocyanat (IPDI), 4,4'-Diisocyanato-dicyclohexylmethan, 2,4- und 2,6-Diisocyanatotoluol oder 4,4'-Diisocyanatodiphenytmethan herstellen. Auch die Umsetzung mit Dicarbonsäuren, aliphatischer, cycloaliphatischer oder aromatischer Natur der Formel

führt zu efindungsgemäß einsetzbaren, Estergruppen aufweisenden Bisoxazolidinen.Starting from the hydroxyoxazolidines described above, the bisoxazolidines to be used according to the invention, preferably having urethane groups, can be reacted with diisocyanates of the formula

(in which Z has the meaning given above), for example hexamethylene diisocyanate. Prepare 3,3,5-trimethyl-5-isocyanatomethyl-cyclohexyl isocyanate (IPDI), 4,4'-diisocyanatodicyclohexyl methane, 2,4- and 2,6-diisocyanatotoluene or 4,4'-diisocyanatodiphenytmethane. Also the reaction with dicarboxylic acids, aliphatic, cycloaliphatic or aromatic in nature of the formula

leads to bisoxazolidines containing ester groups which can be used according to the invention.

In addition to the dicarboxylic acids, their bishlorides can also be used with the elimination of HCl or the bis-esters thereof with the elimination of alcohol. In addition, it is possible to implement the OH group with stoichiometric amounts of hydroxycarboxylic acids or the corresponding lactones before these dimerization reactions. Here comes the use of e.g. Hydroxypropionic acid, hydroxybutyric acid, hydroxycaproic acid etc., or their lactones in question. However, this additional modification is less preferred.

• a) die beispielhaft genannten Oxazolidin- und Isocyanatgruppen aufweisenden Präpolymeren oder
• b) Gemische der beispielhaft genannten NCO-Präpolymeren mit den beispielhaft genannten Bisoxazolidinen, in welchen die Mengenverhältnisse der Komponenten im allgemeinen so gewählt sind, daß für jedes Mol Isocyanatgruppen 0,6 bis 1,1, vorzugsweise 0,65 bis 1,05, Mol Oxazolidingruppen vorliegen,

mit Wasser vermischt. Hierbei wird das Wasser nicht wie in den eingangs genannten Vorveröffentlichungen in Form von Luftfeuchtigkeit sondern in flüssiger Form eingesetzt. Wesentlich ist hierbei, daß die Wassermenge so bemessen wird, daß sie mindestens zur Hydrolyse der Oxazolidingruppen ausreicht, d.h. daß pro Mol Oxazolidingruppen mindestens 1 Mol Wasser zum Einsatz gelangt. Im allgemeinen wird man jedoch stets einen mindestens 100%igen Überschuß über diese Menge an Wasser einsetzen, selbst wenn nicht die Herstellung von wäßrigen Dispersionen oder Lösungen der erfindungsgemäßen Verfahrensprodukte sondern beispielsweise deren Lösungen in organischen Lösungsmitteln hergestellt werden sollen. Durch den Zusatz des Wassers in flüssiger Form und durch die genannte Wassermenge wird eine Additionsreaktion zwischen den Isocyanatgruppen und den aus den Oxazolidingruppen hydrolytisch gebildeten Hydroxylgruppen weitgehend ausgeschlossen, da selbst bei Verwendung eines Oxazolidin-Unterschusses bezogen auf Isocyanatgruppen dann stets eine Kettenverlängerungsreaktion zwischen den Isocyanatgruppen und dem überschüssig vorliegenden Wasser im Vergleich zur Additionsreaktion zwischen Isocyanatgruppen und Hydroxylgruppen vorrangig abläuft. Bei der Herstellung von wäßrigen Lösungen bzw. Dispersionen bei der Durchführung des erfindungsgemäßen Verfahrens wird das Wasser im allgemeinen in Mengen von 40 bis 900, vorzugsweise 55 bis 230 Gew.-%, bezogen auf Oxazolidin- und Isocyanatgruppen aufweisendes Reaktivsystem eingesetzt.When carrying out the method according to the invention

• a) the prepolymers containing the exemplified oxazolidine and isocyanate groups or
• b) Mixtures of the exemplified NCO prepolymers with the exemplified bisoxazolidines, in which the proportions of the components are generally chosen so that for every mole of isocyanate groups 0.6 to 1.1, preferably 0.65 to 1.05, mol Oxazolidine groups are present,

mixed with water. Here, the water is not used in the form of atmospheric moisture, as in the previous publications mentioned at the beginning, but in liquid form. It is important here that the amount of water is such that it is at least sufficient for the hydrolysis of the oxazolidine groups, ie that at least 1 mole of water is used per mole of oxazoline groups. In general, however, an at least 100% excess over this amount of water will always be used, even if it is not the production of aqueous dispersions or solutions of the process products according to the invention but, for example, that their solutions are to be prepared in organic solvents. By adding the water in liquid form and by the amount of water mentioned, an addition reaction between the isocyanate groups and the hydroxyl groups formed hydrolytically from the oxazolidine groups is largely ruled out, since even when using an oxazolidine deficit based on isocyanate groups, a chain extension reaction between the isocyanate groups and the excess water in comparison to the addition reaction between isocyanate groups and hydroxyl groups takes place primarily. In the preparation of aqueous solutions or dispersions when carrying out the process according to the invention, the water is generally used in amounts of 40 to 900, preferably 55 to 230,% by weight, based on the reactive system containing oxazolidine and isocyanate groups.

• Das Isocyanatgruppen und Oxazolidingruppen aufweisende Reaktivgemisch wird in einem geeigneten Lösungsmittel, welches vorzugsweise mit Wasser mischbar sein sollte, zu einer 5 bis 95, vorzugsweise 20 bis 70 gew.-%igen Lösung gelöst. Zu dieser Lösung wird dann unter Rühren das Wasser als solches oder im Gemisch mit mit Wasser mischbarem Lösungsmittel zugesetzt. Die Temperatur hierbei liegt im allgemeinen zwischen 0 und 80°C. Es bildet sich dann sofort eine Lösung des erfindungsgemäßen Verfahrensprodukts in dem Lösungsmittel bzw. Lösungsmittel/Wasser-Gemisch. Geeignete Lösungsmittel sind beispielsweise Dimethylformamid, Dimethylsulfoxid, Aceton, Methyläthylketon oder aber auch Gemische von beispielsweise tertiären Alkoholen wie tert.-Butanol mit aromatischen Lösungsmitteln wie z.B. Toluol.

In the preparation of solutions of the process products according to the invention in organic solvents, the procedure for carrying out the process according to the invention is generally as follows:

• The reactive mixture containing isocyanate groups and oxazolidine groups is dissolved in a suitable solvent, which should preferably be miscible with water, to give a 5 to 95, preferably 20 to 70% by weight solution. The water as such or in a mixture with water-miscible solvent is then added to this solution with stirring. The temperature here is generally between 0 and 80 ° C. A solution of the process product according to the invention is then immediately formed in the solvent or solvent / water mixture. Suitable solvents are, for example, dimethylformamide, dimethyl sulfoxide, acetone, methyl ethyl ketone or else mixtures of, for example, tertiary alcohols such as tert-butanol with aromatic solvents such as toluene.

In the particularly preferred embodiment of the process according to the invention with simultaneous production of aqueous dispersions or solutions of the process products according to the invention in water, either the hydrophilically modified as stated or a reactive system containing an external emulsifier, in particular if it is a liquid, is directly mixed with the water stirred, or one proceeds according to the principle set out above with the use of an auxiliary solvent, the auxiliary solvent advantageously being a water-miscible solvent having a boiling point below 100 ° C., which can be removed by distillation after the reaction according to the invention has taken place. In this production of aqueous dispersions or solutions, the dispersion or dissolution of the prepolymers and their chain extension take place practically simultaneously. A decisive advantage over the previously known methods of the prior art for the solvent-free or low-solvent production of aqueous polyurethane dispersions is that an intimate mixing with the chain extender takes place even before being brought together with water, or chemical fixation even before being brought together with water the chain-extending group (oxazolidine group) takes place, so that the chain extension leads to particularly homogeneous products. The process according to the invention is particularly suitable for the production of aqueous dispersions or solutions, which have a solids content of 10 to 70, preferably 30 to 65 wt .-%.

The particles of the discontinuous phase in the dispersions generally have a diameter of 50 to 1000 nm. The preparation of sols with an average particle diameter of the discontinuous phase of about 1-50 nm or clear, aqueous solutions in which the solid is present in molecularly disperse form or at most in the form of associates is also possible according to the invention.

Whether solutions or dispersions of the polyurethanes in water are obtained in the process according to the invention depends above all on the molecular weight and the hydrophilicity of the dissolved or dispersed particles, which in turn depends on the suitable choice of type and quantitative ratio of the starting materials, in particular in the preparation of the NCO prepolymers , can be adjusted according to the known principles of polyurethane chemistry. For example, the use of an NCO prepolymer with a mean NCO functionality slightly below 2 leads to the polyaddition reaction being terminated before excessively high molecular weights are reached. The polyurethanes produced by the process according to the invention and present in aqueous dispersion or solution are on a par with the known polyurethanes produced in organic solvents. Films made from them have excellent mechanical strength and hydrolysis resistance and can be used for a wide variety of applications.

Because of the pendant hydroxyl groups incorporated in the process products according to the invention, these can be crosslinked after shaping, for example by evaporation of the solvent or water after a chemically or thermally activatable crosslinking agent has been added to the solution or the dispersion. Suitable crosslinking agents are e.g. Polyisocyanates with blocked isocyanate groups or melamine resins which are reactive towards hydroxyl groups. Even if the process products according to the invention are not chemically crosslinked via the pendant hydroxyl groups, these can be advantageous since they often increase the physical affinity of the process products according to the invention for substrates which are coated with the compounds according to the invention.

All parts mentioned in the following examples are parts by weight.

example 1

eingerührt und die Mischung anschließend unter kräftigem Rühren mit 5060 Teilen entionten Wassers versetzt. Die entstandene wäßrige Dispersion hatte einen Feststoffgehalt von 30% und eine Viskosität von 14 Sekunden (Fordbecher, 4 mm). Sie zeigte im durchscheinenden Licht einen Tyndall-Effekt. Die Dispersion trocknet zu einem klaren, farblosen und klebfreien Film auf, der folgende mechanische Daten besitzt:

• Zugfestigkeit: 37,2 MPa
• Bruchdehnung: 620%

1237.5 parts of a polybutylene adipate (MW = 2250) and 191.3 parts of a four-propoxylated adduct of 2-butenediol-1,4 and sodium bisulfite (MW = 425), hereinafter referred to as "adduct", were at 120 ° C in Water jet vacuum dewatered 488.4 parts of 1-isocyanato-3-isocyanatomethyl-3,3,5-trimethylcyclohexane were added to this mixture at 70 ° C. and the mixture was stirred after raising the temperature to 100 ° C. until the NCO content of Melt was 5.3%. After cooling to 60 ° C, 437.4 parts of a bisoxazolidine of the formula

stirred in and then mixed with vigorous stirring with 5060 parts of deionized water. The resulting aqueous dispersion had a solids content of 30% and a viscosity of 14 seconds (Ford cup, 4 mm). It showed a Tyndall effect in the translucent light. The dispersion dries to a clear, colorless and tack-free film, which has the following mechanical data:

• Tensile strength: 37.2 MPa
• Elongation at break: 620%

• Zugfestigkeit: 45,3 MPa
• Bruckdehnung: 410%

330 parts of the dispersion were mixed with 15 parts of a hexamethyl / butyloxymethylmelamine and cast into a film. After drying, the film was heated to 130 ° C for 20 minutes. The mechanical values measured on this film were:

• Tensile strength: 45.3 MPa
• Elongation at break: 410%

The film was not sticky after moistening with toluene and acetone and did not dissolve in hot DMF.

Example 2

versetzt. Unter kräftigem Rühren wurden 5100 Teilen entionten Wassers zugegeben. Die entstandene Dispersion hatte einen Festkörpergehalt von 30% und eine Viskosität von 18 Sekunden (Fordbecher, 4 mm). Sie zeigte im durchscheinenden Licht einen Tyndall-Effekt.The NCO prepolymer from Example 1 was at 60 ° C with 361.8 parts of a bisoxazolidine of the formula

transferred. 5100 parts of deionized water were added with vigorous stirring. The resulting one Dispersion had a solids content of 30% and a viscosity of 18 seconds (Ford cup, 4 mm). It showed a Tyndall effect in the translucent light.

The dispersion dries to a clear, colorless and tack-free film which, after the water has been completely removed, has a Shore A hardness of 78. After heating to 130 ° C. for 20 minutes, the hardness had risen to 85 (Shore-A) and the film was only swellable in hot DMF, but no longer soluble.

Example 3

eingerührt und die Mischung anschließend unter kräftigem Rühren mit 4070 Teilen entionten Wassers versetzt. Die entstandene wäßrige Dispersion hatte einen Feststoffgehalt von 30% und eine Viskosität von 15 Sekunden (Fordbecher, 4 mm). Die Dispersion zeigte im durchscheinenden Licht einen Tyndall-Effekt. Die Dispersion trocknete nach dem Vergießen zu einem klaren, harten Film auf, der jedoch mit dem Fingernagel leicht zu ritzen war. Die Bleistifthärte betrug HB-H. Nach 20-minütigem Erhitzen auf 130°C war die die auf 3 H angestiegen.600 parts of a polyethylene diol phthalate (MW = 2000) and 525 parts of a polyethylene diol phthalate adipate (MW = 1750) and 170.4 parts of the adduct described in Example 1 were dewatered at 120 ° C. in a water jet vacuum. 285.6 parts of hexamethylene diisocyanate were added to this mixture at 70 ° C., and the mixture was stirred after the temperature had been raised to 100 ° C. until the NCO content of the melt was 4.8%. After cooling to 80 ° C 209 parts of an oxazolidine of the formula

stirred in and the mixture then mixed with vigorous stirring with 4070 parts of deionized water. The resulting aqueous dispersion had a solids content of 30% and a viscosity of 15 seconds (Ford cup, 4 mm). The dispersion showed a Tyndall effect in the translucent light. After pouring, the dispersion dried into a clear, hard film, which was easy to scratch with a fingernail. The pencil hardness was HB-H. After heating at 130 ° C. for 20 minutes, the temperature had risen to 3 hours.

Example 4

eingerührt und die Mischung anschließend unter kräftigem Rühren mit 2230 Teilen entionten Wassers versetzt. Es entstand eine wäßrige Dispersion mit einem Feststoffgehalt von 40% und einer Viskosität von 20 Sekunden (Fordbecher, 4 mm). Die Disperion zeigte im durchscheinenden Licht einen Tyndall-Effekt.300 parts of a Polyäthandiolphthalats (MW = 2000) and 612.5 parts of a Polyäthandiolphthaladadipates (MW = 1750) as well as 13.4 parts of 1,1, 1-trishydroxymethylpropane and 148.8 parts of the adduct described in Example 1 were at 120 ° C in Water jet vacuum drained. 285.6 parts of hexamethylene diisocyanate were added to this mixture at 70 ° C. and the mixture was stirred after the temperature had been raised to 100 ° C. until the NCO content of the melt was 4.3%. After cooling to 80 ° C, 252.7 parts of an oxazolidine of the formula

stirred in and then mixed with vigorous stirring with 2230 parts of deionized water. The result was an aqueous dispersion with a solids content of 40% and a viscosity of 20 seconds (Ford cup, 4 mm). The dispersion showed a Tyndall effect in the translucent light.

Example 5

eingerührt und die Mischung anschließend unter kräftigem Rühren mit 6160 Teilen entionten Wassers versetzt. Die entstandene Dispersion hatte einen Festkörpergehalt von 30%. Die Dispersion zeigte im durchscheinenden Licht einen Tyndall-Effekt.1000 parts of an ethanediol / 1,4-butanediol / diethylene glycol polyadipate (MW = 2000) and 1100 parts of an adduct from stoichiometric amounts (i) of a polyether alcohol started on n-butanol and consisting of 83% ethylene oxide and 17% propylene oxide (MW = 1900), ( ii) hexamethylene diisocyanate and (iii) diethanolamine were dewatered at 120 ° C. in a water jet vacuum. 369.2 parts of hexamethylene diisocyanate were added to this mixture and, after the temperature had been raised to 100 ° C., the mixture was stirred until the NCO content of the melt was 4.1%. After cooling to 30 ° C, 358.2 parts of an oxazolidine of the formula

stirred in and then mixed with vigorous stirring with 6160 parts of deionized water. The resulting dispersion had a solids content of 30%. The dispersion showed a Tyndall effect in the translucent light.

Example 6

eingerührt und die Mischung anschließend unter kräfigem Rühren mit 3320 Teilen entionten Wassers versetzt. Die entstandene Dispersion hatte einen Festkörpergehalt von 40% und eine Viskosität von 18 Sekunden (Fordbecher, 4 mm). Sie zeigte im durchscheinenden Licht einen Tyndall-Effekt. Die Dispersion trocknet zu einem klaren, farblosen und elastischen Film auf, der folgende mechanische Daten besitzt:

• Zugfestigkeit: 28,6 MPa
• Bruckdehnung: 930%

1192.5 parts of a polybutanediol adipate (MW = 2250) and 137.5 parts of a propylene oxide polyether (MW = 550) started on bisphenol A and 85.5 parts of one started on n-butanol Polyether alcohol consisting of 85% ethylene oxide and 15% propylene oxide and 85.2 parts of the adduct described in Example 1 were dewatered at 120 ° C. in a water jet vacuum. 488.4 parts of 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane were added to this mixture at 70 ° C., and the mixture was stirred after the temperature had been raised to 100 ° C. until the NCO content was 5.0 % amounted to. After cooling to 60 ° C, 437.4 parts of a bisoxazolidine of the formula

stirred in and then mixed with vigorous stirring with 3320 parts of deionized water. The resulting dispersion had a solids content of 40% and a viscosity of 18 seconds (Ford cup, 4 mm). It showed a Tyndall effect in the translucent light. The dispersion dries to a clear, colorless and elastic film, which has the following mechanical data:

• Tensile strength: 28.6 MPa
• Elongation at break: 930%

• Zugfestigkeit: 41,7 MPa
• Bruchdehnung: 430%

250 parts of the dispersion were mixed with 20 parts of a butanone-capped triisocyanatohexylbiuret. After a film had dried on, it was heated to 160 ° C. for 30 minutes. The mechanical data measured on this film were:

• Tensile strength: 41.7 MPa
• Elongation at break: 430%

Example 7

eingerührt und die Mischung anschließend unter kräftigem Rühren mit einer Mischung aus 2260 Teilen entionten Wassers und 76 Teilen Äthylenglykolmonoäthylester versetzt. Es bildete sich eine Dispersion mit einem Festkörpergehalt von 40%. Sie zeigte im durchscheinenden Licht einen Tyndall-Effekt.500 parts of a polyethylene phthalate (MW = 2000) and 332 parts of a polypropylene glycol ether (MW = 550) started on bisphenol A, as well as 13.4 parts / trishydroxymethyl propane and 104 parts of the adduct described in Example 1 were dewatered at 120 ° C. in a water jet vacuum. 320 parts of hexane diisocyanate were added to this mixture at 70 ° C. and the mixture was stirred after the temperature had been raised to 100 ° C. until the NCO content was 4.7%. After cooling to 40 ° C, 246 parts of an oxazolidine of the formula

stirred in and then mixed with vigorous stirring with a mixture of 2260 parts of deionized water and 76 parts of ethylene glycol monoethyl ester. A dispersion with a solids content of 40% was formed. It showed a Tyndall effect in the translucent light.

Example 8

und 84 Teilen Äthylenglykolmonoäthyläther wurden unter kräftigem Rühren 2500 Teile entionten Wassers zugesetzt. Es entstand eine Dispersion mit einem Festkörpergehalt von 38%. Sie zeigte im durchscheinenden Licht einen Tyndall-Effekt. Nach dem Ausgießen und Auftrocknen bildete sich ein klarer zäher Film, der hohe Härte besäß.552 parts of a polypropylene glycol ether (MW = 550) started on bisphenol A were dewatered at 120 ° C. in a water jet vacuum and mixed at 70 ° C. with 320 parts of hexane diisocyanate. After the temperature had been raised to 100 ° C., the mixture was stirred until the NCO content was 8.7%. The mixture was cooled to 50 ° C and 238 parts of an adduct of 20 moles of ethylene oxide with 1 mole of iso-nonylphenol were dissolved in it. After adding 320 parts of an oxazolidine of the formula

and 84 parts of ethylene glycol monoethyl ether, 2500 parts of deionized water were added with vigorous stirring. A dispersion with a solids content of 38% was formed. It showed a Tyndall effect in the translucent light. After pouring out and drying, a clear, tough film was formed which was extremely hard.

Example 9

12 Stunden lang gerührt. Darauf wurden 105 Teile Äthylenglykolmonoäthyläther zugesetzt und bei 50°C 1590 Teile entionten Wassers eingerührt. Die entstandene Dispersion hatte einen Festkörpergehalt von 40% und zeigte im durchscheinenden Licht einen Tyndall-Effekt. Sie trocknete zu einem klaren zähen und glänzenden Film auf.556 parts of a polypropylene glycol ether (MW = 550) started on bisphenol A and 93.6 parts of the adduct described in Example 1 were dewatered at 120 ° C. in a water jet vacuum. 320 parts of hexane diisocyanate were added to this mixture at 70 ° C. and the mixture was stirred after the temperature had been raised to 100 ° C. until the NCO content was 6.3%. At 70 ° C after mixing with 80 parts of an oxazolidine of the formula

Stirred for 12 hours. 105 parts of ethylene glycol monoethyl ether were then added and 1590 parts of deionized water were stirred in at 50.degree. The resulting dispersion had a solids content of 40% and showed a Tyndall effect in the translucent light. It dried into a clear, tough and shiny film.

Claims (2)

1. Process for the preparation of substantially linear isocyanate polyaddition products containing hydroxyl groups in side-chains by the reaction of reactive systems which contain free isocyanate groups and oxazolidine groups with water, characterised in that

a) substantially linear prepolymers which have both isocyanate end groups and oxazolidine end groups or

b) a mixture containing substantially linear isocyanate prepolymers and bis-oxazolidines are chain lengthened by mixing with water, using a quantity of water calculated to provide at least 1 mol of water per mol of oxazolidine groups present in the reaction mixture.

2. Process according to claim 1, characterised in that the prepolymers used are hydrophilically modified and/or contains an external emulsifier and water is used in a large excess in the chain- lengthening reaction so that the polyaddition products are directly obtained as an aqueous dispersion or solution.