DE2427274A1 - Microporous polyurethane coatings - prepd by coagulating polyurethane contg anionic and or cationic polyurethanes - Google Patents

Abstract

A process for prepg. microporous, steam permeable coatings and surfaces esp. textile coatings or adhesives and films, by coagulating hygroscopic polyurethane-(urea) solns. is claimed in which cationic and/or anionic polyurethane (urea) suspensions are added to the solns. before coagulation. The coatings have better resistance to hydrolysis and less water absorption.

Description

Process for the production of microporous sheets The present The invention relates to an improved method for producing microporous sheet-like structures through coagulation of polyurethane or polyurea solutions.

The improvement is achieved by ate in the solutions before the Cationic and / or anionic polyurethane (urea) e suspended in coagulation will.

A whole series of processes is already known in order to Water vapor permeable coatings made from solutions of polyurethanes (e.g. in dimethylformamide) by coagulation with non-solvents (e.g. water). The desired The microporous structure of the polymers should be very specific by adhering to them and specified conditions can be achieved during the coagulation process.

The use of polyurethane or polyurethane urea solutions in highly polar solvents such as dimethylformamide or dimethylacetamide (if necessary using other polymers such as polyvinyl chloride or polyacrylonitrile) for the production of films, coatings aif fabrics or as binder for nonwovens, the solvent being treated with water, glycerine or other liquids are removed with the aforementioned highly polar solvents miscible, but incompatible with the polyurethanes, is used for the first time in the German No. 888,766. There is already the use of others Solvents which are generally nonsolvents for the polyurethane (e.g. Methylene chloride, acetone or benzene).

In a number of later publications, special steps were taken specified in order to process products with a greater or lesser degree of certainty microporous structure to arrive. For example, the German patent specification 1 110 607 proposed for the coagulation of polyether-based polyurethanes, hygroscopic Polyurethane.

solutions (e.g. dimethylformamide serves as a solvent) the Effect of an atmosphere containing water vapor, possibly in circulation expose to which a relative humidity of 15 to 100% at a temperature of the dry thermometer from 10 to 38 0C. Because of the absorption of water due to the hygroscopicity of the solvent, the polyurethane starts out of solution falling out from the surface, probably preforming the microporous ones Structure. When inserting the films or coatings pregelled in this way The hygroscopic solvent is removed from the water with coagulation of the solution Film completely removed.

The working method according to DAS 1 110 607 requires one in its humidity precisely conditioned atmosphere and long exposure time in this humid atmosphere. However, the results are technically hardly reproducible, even if only Polyether urethanes are processed.

If the pre-gelation is omitted by the action of the above-described humid atmosphere, 90 are either transparent and impermeable or coarse-pored, Inhomogeneous films obtained which are unusable for the intended purpose.

The German Offenlegungsschrift 1 444 163 gives a somewhat modified one Process on: By adding smaller amounts of nonsolvents (e.g. water) the polyurethane solution is only in the state of beginning phase separation, i.e. brought into a slightly cloudy, dispersion-like form before (after painting in surface form) directly, i.e. without pre-gelling in a humid atmosphere, by immersion is coagulated into the nonsolvent.

When working according to DOS 1 444 163 it is difficult to get the right amount to meet nonsolvents for the preparation of the colloidal dispersions. The process also uses raw materials in an unstable state: the The properties of the dispersion change over time and as a function of temperature and moisture, the elastomer dispersions in a pasty, no more pass smoothly deformable state.

Another method is described in German Offenlegungsschrift 1 444 165 indicated, according to which the polymer solution without pre-gelation by direct coagulation in a mixture of nonsolvent and solvent (e.g.

Dimethylformamide / H20 in a mixing ratio between 10:90 and 95: 5) should be transferred into microporous films.

The procedure according to DOS 1 444 165 requires extended coagulation times, especially for baths with a lot of solvents, because the polyurethane only coagulates slowly. Thus, the capacity of a given production facility is greatly reduced.

According to another variant, which is in the Belgian patent specification 624 250 is described, one adds so much non-solvent to the polyurethane solution that that the polymer separates out as a gel. Only then is this gel applied a substrate and coagulates with nonsolvent (water) to form a microporous Structure. However, with this procedure it is technically difficult to separate the gel and to process into a homogeneous coating.

In the German Auslegeschrift 1 238 206 it is stated that a direct coagulation of elastomer solutions then leads to microporous structures, if you put the coated substrates in baths which are close to the boiling point the bath liquid are heated, e.g. in hot water of 950, coagulated.

Somewhat improved results are obtained, albeit with the pre-gelation takes place at elevated temperature. For example, DOS 2 025 616 describes a method for the production of microporous fabrics in which a thin layer of the Polyurethane solution in a water vapor atmosphere with at least 50% relative humidity exposes at temperatures above 65 0C, then in aqueous coagulation baths most of the solvent is removed and then dried.

According to DOS 2 125 908, a layer of a polyurethane solution is applied Water vapor with a temperature between 10100 and 1900C passed until the content the organic solvent layer decreased to less than 50% by weight and the layer changed into a solid, mechanically stable microporous sheet-like structure is. This method has the particular advantage that in a short time and in one In a single process step, a microporous end product is made from a polyurethane solution arises.

The broad state of the art just described suggests that it should in principle be possible under any process conditions (temperature , Solvent-precipitant ratio, pre-gelation time, coagulation bath) Polyurethane solutions through coagulation films or coatings with a microporous structure In practice, however, it turned out that all of the processes mentioned only with very little certainty and only when using very specific ones Polymer solutions yield useful end products, especially when the process can be transferred from the laboratory to large-scale production should. Even minor changes in the chemical structure of the polyurethane can result often with otherwise completely identical process conditions to homogeneous, transparent ones and fabrics impermeable to water vapor0 Proven to be particularly sensitive In this regard, the higher molecular weight used to build up the polyurethane terminal hydroxyl groups containing polyester or

Polyether. In many cases, even using different ones Batches of the same starting materials, once microporous and once homogeneous process products. Even usable basic types of polyesters or polyethers must therefore be part of the batch tested and selected in batches for the coagulability of the finished polyurethane solution as criteria for qualification of the starting components however, the usual parameters such as molecular weight, OH number, etc. cannot be used, because often apparently completely identical products with very different coagulation behavior the polyurethane solution. It therefore requires production on a trial basis in each case of elastomer solutions and their coagulation on a pilot plant scale, to the special In case of necessary procedural conditions, usually to be observed within very narrow limits to find. However, many approaches only lead to partially microporous ones in each case or transparent foils.

An explanation for these surprising effects could not yet be found being found. Despite many efforts, it was not possible to find any interfering components to discover in the raw materials or elastomer solutions that cause coagulation to become microporous Hinder products.

It has also been proposed many times to improve the polymer solutions to add certain coagulation auxiliaries to the coagulability. So describe the DAS 1 270 276, the DOS 1 694 171 and the DOS 1 769 277 methods of manufacture water-vapor-permeable sheet-like structure in which solutions of 90 to 70 parts by weight of NCO-group-free polyurethanes or polyureas and 10 to 30 parts by weight of high molecular weight, essentially linear, cationic polyurethanes, the 0.5 contain up to 2.0 wt .-% quaternary ammonium nitrogen atoms, optionally after Gelation in moist air with water or a mixture of water and solvent be coagulated. In addition to the cationic polyurethanes, these solutions can be used as additional coagulation regulators also contain anionic tannins.

The use of such previously known coagulation aids Although it brings noticeable improvements in terms of the coagulability of the polyurethane solutions, especially for approaches on a laboratory scale. When transferring to the production scale but the difficulties outlined above remain. The coagulability is so different from batch to batch of the polyurethane that each elastomer solution continues must first be examined with great effort for their usability before use got to.

The use of an anionic tanning agent is particularly problematic, for example a sulfonic acid phenol-formaldehyde condensate. The coagulation Although certain polyurethanes are favored, technically serious ones occur Disadvantages on. This is how most of the tanning agent, which is usually present as an alkali salt, is used in the coagulation bath, which in many cases contains dimethylformamide and water, for washed out for the most part. With simultaneous use of cationic Polyurethanes are also partially washed out, i.e. they bleed out, so that High molecular weight impurities gradually arise under the production conditions, which can cause damage to the still soft porous surface structure. The dissolved, larger part of the tanning agent causes difficulties in recovery (Distillation) of the organic solvent diluted with water, (e.g. DMF) because the precipitated tannin is separated from the solvent before it is distilled must become.

Another disadvantage is that the low in the microporous film the remaining amount of phenol-formaldehyde condensate is sufficient to cause a significant deterioration to effect the light stability. In addition, the so coagulated are microporous Flat structures have a harder grip, which is generally undesirable.

Surprisingly, it has now been found that the coagulation without the disadvantages mentioned of the use of tannin are significantly improved and more economical can be carried out if the polyurethane solutions to be coagulated are certain cationic or anionic polyurethane urea suspensions alone or preferably simultaneously contain cationic and anionic polyurethane (urea) s in salt form.

It succeeds in this way, not even the coagulation previously to regulate processable polyurethane solutions so that fabrics with more satisfactory Microporosity arise.

The present invention is therefore a method for Production of microporous, water-vapor-permeable flat structures by coagulation of hygroscopic polyurethane (urea) solutions, which is characterized is that the polyurethane (urea) solutions before coagulation suspensions of cationic and / or anionic polyurethane (ureas) s are added.

Combinations with as low a value as possible are particularly advantageous Content of ionic groups and the largest possible amount of separately produced nonionic polyurethane (ureas). The sum of the cationic and anionic Groups is, based on 100 g of microporous PUR fabric, between 0.30-0.0001, preferably between 0.05-0.005 ion equivalents. The equivalent ratio between cationic and anionic groups is preferably between 20: 1 and 1:20, especially preferably between 10: 1 and 1: 2.

A particular advantage of the inventive use of mixed Dispersions compared to the known use of cationic polyurethanes as Coagulation regulators is that the total ion content is coagulation regulating with the same Effect can be kept much lower. The manufactured according to the invention Films and coatings therefore have increased resistance to hydrolysis. The swelling in water is also far with the same number of ionic groups lower when the film contains both cationic and anionic polyurethanes.

The nonionic polyurethanes used in the process according to the invention a large number of compounds accessible by the most varied of methods are suitable, which, however, all contain the typical urethane grouping (cf. Ullmann, Enzyklopädie der technical chemistry, 4th edition, volume 14, p.

338 to 363). For example, polyurethanes in the narrower sense can be used, which from higher molecular weight polyhydroxyl compounds, dialcohols and diisocyanates are accessible by single or multi-stage processes (via NCO pre-adducts).

For example, polyesters or polyethers can be used with an excess reacted on diisocyanates to form NCO pre-adducts and these then with diol compounds such as 1,4-butanediol, N-methyl-diethanolamine, hydroquinone bis (hydroxyethyl ether) or Terephthalic acid bis-hydroxyethyl ester in equivalent or slightly lower amounts Quantities are chain-extended, both in the melt and in solvents can work. But you can also use the components directly in a one-step process convert to the elastomer and then dissolve it in highly polar solvents.

Polyurethane ureas, as used as "components", are also particularly suitable a "in the German Auslegeschrift 1 270 276. For their production leaves higher molecular weight, essentially linear polyhydroxyl compounds with terminal hydroxyl groups with a molecular weight between 400 and 5000 and optionally further low molecular weight dialcohols, amino alcohols or diamines with an excess of diisocyanates initially to a pre-adduct with terminal Isocyanate groups react and then sets this with water or with bifunctional Compounds that have at least one of their isocyanate-reactive compounds Contain hydrogen atoms bonded to nitrogen atoms. Because of the compared significantly higher reactivity and conversion rate of these chain extenders to diols the reaction is preferred in highly polar, water-soluble solvents with a Boiling point carried out above 1000C.

The production of such polyurethane (urea) s and their solutions is for example in the German patents 888 766, 1 123 467, 1 150 517, 1 154 937, the German Auslegeschriften 1 161 007, 1 183 196, 1 186 618, the Belgian Patents 649 619, 646 637, 658 363, 664 344, 664 346, 666 208, the French U.S. Patents 1,380,082, 1,371,391, 1,383,077 and U.S. Patents 2,929 803, 2 929 804, 3 040 003.

Higher molecular weight, essentially linear polyhydroxyl compounds with terminal hydroxyl groups, which are used in the manufacture of elastomeric polyurethanes are suitable, for example, polyesters, polyesteramides, polyethers, polyacetals, polycarbonates or poly-N-alkyl urethanes or their mixtures, including those with ester, ether, Amide, urethane or N-alkyl urethane groups with molecular weights between 400 and 5000 and melting points of preferably +60 to -500C.

Particular mention should be made of polyesters made from adipic acid and dialcohols or mixtures of dialcohols, e.g. ethylene glycol, propylene glycol, 1,4-butanediol, 2,2-Dimethylpropanediol-1,3, hexanediol-1,6 or bishydroxymethylcyclohexane.

Diols or mixtures of diols with five or more are preferred C atoms because of the good resistance to hydrolysis of the polyesters made from them. Polyesters obtained by condensation of caprolactone and amines or diols such as hexanediol-l, 6 with narrow molecular weight distribution are also suitable. Particularly good microporous films with excellent surface properties and good water vapor permeability are derived from mixed polyesters made from 90 - 60 wt .-% adipic acid and 10 to 40 wt .-% terephthalic acid and a diol, preferably Ethylene glycol, 1,4-butanediol neopentyl glycol and / or 1,6-hexanediol, produced have been.

The polyurethanes can be particularly resistant to hydrolysis Achieve if one uses dihydroxypolycarbonates as higher molecular weight polyhydroxyl compounds based on 1,6-hexanediol or mixed polycarbonates are used in their production in small amounts (up to about 20 mol%) dicarboxylic acids, preferably adipic acid, are added became. Mixtures of the compounds mentioned can also be used.

Excellent hydrolysis-resistant polyurethane ureas can also be used obtained from polyethers, preferably from polytetramethylene ether diols, which may be can also be used as mixed polyethers.

Suitable higher molecular weight polyhydroxyl compounds are also graft polymers from partially saponified ethylene-vinyl ester copolymers and vinyl compounds, as described in DBP 1 225 381.

The graft polymers consist of 10 to 70%, preferably 15 to 60%, of a vinyl ester originally containing 25 to 75%, saponified to 10 to 80% Ethylene vinyl ester copolymer and 30 to 90% vinyl chloride polymer together. The preparation of such polymers is described, for example, in the French patent 1 409 527.

In the preparation of the graft polymers can optionally also minor amounts of other monomers, such as vinyl esters, «, ß-unsaturated mono- and / or dicarboxylic acids having 3 to 4 carbon atoms including their derivatives, such as e.g. Oxyalkylacrlate (-methacrylate) or maleic acid half esters have also been used be. These monomers or their mixtures with one another can contain up to 40% Make up% of the monomer mixture to be grafted on. The production of these graft polymers is described, for example, in French patent specification 1,436,267.

Suitable diisocyanates, if appropriate in a mixture, are aliphatic, cycloaliphatic, araliphatic and aromatic diisocyanates or heterocyclic ones Diisocyanates. Particular mention may be made of diisocyanates with a symmetrical structure, e.g. Diphenylmethane-4,4'-diisocyanate, diphenyldimethylmethane -4,4'-diisocyanate, 2,2-6,6'-tetramethyldiphenylmethane diisocyanate, diphenyl-4,4 "-diisocyanate, diphenyl ether-4,4t-diisocyanate or their alkyl, alkoxyl or halogen-substituted derivatives, also toluene-2,4- respectively.

2,6-diisocyanate or its technical mixtures, diisopropyl-phenylene-diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate or a, a, afa'-tetramethyl-p-xylylene diisocyanate or their other alkyl or halogen substitution products, dimeric toluene-2,4-diisocyanate, Bis (3-methyl-4-isocyanatophenyl) urea or naphthylene-1,5-diisocyanate. (Cyclo) aliphatic diisocyanates, such as hexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, Dicyclohexylmethane-4,4'-diisocyanate, 1-isocyanato-5-isocyanatomethyl-3,5,5-trimethylcyclohexane or 2,2,4-trimethylhexane-1,6-diisocyanate give very little discoloration on exposure to light Products.

Diphenylmethane-4,4'-diisocyanate, the isomeric Tolylene diisocyanate, p-phenylene diisocyanate and - if necessary in part - Hexamethylene diisocyanate or dicyclohexylmethane-4,4'-diisocyanate are used.

The higher molecular weight polyhydroxyl compounds are mixed with the diisocyanates approximately in a molar ratio of 1: 1.25 to 1: 6.0, optionally in several stages in the melt or in solvents inert towards isocyanates, such as tetrahydrofuran, Dioxane or chlorobenzene or dimethylformamide, at temperatures from about 20 to 1300e, preferably 40 to 1000C, implemented.

One keeps such reaction times that an essentially linear one Pre-adduct with terminal -NCO groups is obtained, which in the implementation with approximately equivalent amounts of bifunctional chain extenders essentially linear, in polar solvents soluble elastomeric polyurethane or a Polyurethane urea yields.

As mentioned above, together with the higher molecular weight polyhydroxyl compounds also low molecular weight diols (molecular weight preferably below 250), e.g. ethylene glycol, 1,4-butanediol, bis-N, N- (B-hydroxyethyl) -methylamine, bis-N, N - (- hydroxypropyl) -methylamine, N, N'-bis-hydroxysthylpiperazine or hydroquinone bis (- hydroxyethyl ether) is also used will. The amount of low molecular weight diols is preferably such that 0.1 to 4 moles of OH groups per mole of OH groups of the higher molecular weight polyhydroxyl compound of the low molecular weight diol are present, increase diols with tertiary nitrogen at the same time the dyeability, improve the lightfastness and create the point of attack for further follow-up treatments, e.g. cross-linking with strongly alkylating agents Links.

The NCO group content of the pre-adducts (calculated on the solvent-free pre-adduct) is of crucial importance for the properties of the polyurethane ureas obtained from them. It must be at least 0.75 wt .-% and should preferably be between about 1.0 and about 7.6% by weight, especially between about 1.5 and 5.5% by weight, so that the polyurethane ureas sufficiently high melting points, tensile strengths, elongation at break and stress values exhibit. The NCO content is in the pall of the chain extension reaction with water preferably higher, e.g.

between 3.5 and 7.6 percent by weight, as part of the NCO groups is first saponified to amino groups.

The chain extenders should have a molecular weight of 18 to about 500, preferably from 32 to 350, and can optionally be mixed or can be used in stages. In addition to water and the above-mentioned low molecular weight diols, for example ethylenediamine, 1,2- or 1,5-propylenediamine, 1,4-tetramethylenediamine, 1,6-hexamethylenediamine, 2,2,4-trimethylhexanediamine -1.6, 1-methylcyclohexane-2,4-diamine, 4,49-diaminodicyclohexylmethane, bis (-aminopropyl ) -methylamine, N, N-bis (aminopropyl) -piperazine, araliphatic diamines such as 195-tetrahydronaphthalene, or aromatic diprimary amines, such as 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, l-methyl-2,4-diaminobenzene or araliphatic diprimary diamkines, such as m-xylylenediamine, p-xylylenediamine, a, a, a ', a'-tetramethyl-p-xylylenediamine or 1,3-bis (ß-aminoi8o-propyl) -benzene, Hydrazine compounds, such as carbodihydrazide, adipic acid dihydrazide, succinic acid dihydrazide, Glutaric acid dihydrazide, pimelic acid dihydrazide, hydracrylic acid dihydrazide, terephthalic acid dihydrazide, Isophthalic acid dihydrazide, ß-semicarbazido-ethane-carbazine ester, ß-aminoethyl-semicarbazide, ß-Semicarbazido-propionic acid hydrazide, 4-semicarbazido-benzoic acid hydrazide, also Hydrazine hydrate or N, N'-diaminopiperazine. These chain extenders can can be used individually, in a mixture or together with water. It can too (preferably less than 30 mol percent) secondary diamines9, preferably with symmetrical structure, such as piperazine or 2,5-dimethylpiperazine can be used.

When using chain extension mixtures, it usually increases the solubility of the polyurethane ureas and the melting point of the elastomers decreases away. Preferred chain extenders are 1,4-butanediol, ethylenediamine, m-xylylenediamine, hydrazine, carbodihydrazide, aliphatic dicarboxylic acid hydrazides used like glutaric acid dihydrazide and water0 The implementation the NCO-7or adducts with the chain extenders takes place in highly polar, water-soluble, Solvents boiling above 130 ° C. Mention should be made of amide or sulfoxide groups Solvents with the ability to form strong hydrogen bonds "for example Dimethylformamide N-methylpyrroli.don1 diethylformamide, dimethylacetamide, formylmorpholine, Hexamethylphosphoramide, dimethyl sulfoxide, tetramethylurea or their mixtures.

The technically preferred solvent is dimethylformamide.

To a certain extent, the (aagg n of the chemical composition of the polyurethane) is around 35% by weight of the amount of solvent1 can be less polar solvents, which are not suitable for the polyurethaneureas alone dissolve, can be added to the highly polar solvents, e.g. tetrahydrofuran, Dioxane, acetone or glycol monomethyl ether acetate. The concentration of the elastomer solutions should preferably be about 5 to 33% by weight, especially 15 to 27% by weight, where the viscosities are preferably between 1 and 1000 poise, especially between 50 and 800 poise / 250C.

Other suitable polyurethane elastomers are also those that Conversion of bis-chlorocarbonic acid esters and diamines or from bis-carbonic acid chlorides and diamines are obtained (wherein preferably each of the components is a higher molecular weight compound with a molecular weight of about 400 to 5000). Reaction products of higher molecular weight bis-chloroformic acid esters may be mentioned by way of example of polyhydroxy-oil compounds with diamines and reaction products of higher molecular weight Compounds with amino end groups (made e.g. from polyhydroxyl compounds, Diisocyanates and chain extension with noticeably excess amounts of compounds with terminal NH2 groups) and bis-acid chlorides or bischloroformic acid esters. Such connections are z. Tie U.S. Patents 2,929 801, 2 929 802, 2 962 470, 2 957 852. Segmented ones are also suitable Polyester or polyether elastomers, such as those in the French Patents 1,354,55 and 1,359,090 and in Belgian patent 574,385 to be discribed.

According to the invention suitable cationic polyurethanes are z, B. after the DAS 1 270 276 obtained if at least one component in the construction of the polyurethane with one or more basic tertiary nitrogen atoms is also used and the basic tertiary nitrogen atoms of the polyurethane with alkylating agents or inorganic or organic acids are reacted. It is basically there no matter from which point of the polyurethane macromolecule the basic ones are Nitrogen atoms are located.

Conversely, you can also use polyurethanes with reactive, for quaternizing React capable halogen atoms with tertiary amines. Furthermore, cationic Manufacture of polyurethane with chain-building quaternization by e.g. from optionally higher molecular weight diols and isocyanates with reactive halogen atoms or diisocyanates and halogen alcohols producing dihalo urethanes and this reacts with ditertiary amines. Conversely, one can make connections with two Isocyanate groups and tertiary amino alcohols produce ditertiary diaminourethanes and react them with reactive dihalogen compounds. Of course the cationic polyurethane mass can also consist of a cationic salt-like starting component, about a quaternized basic polyether or a quaternary nitrogen containing Isocyanate can be produced. These manufacturing methods are e.g.

in the German Auslegeschriften 1 184 946, 1 178 586 and 1 179 363, der U.S. Patents 3,686,108 and Belgian Patents 653 223, 658 026, 636 799.

There are also those suitable for building up the salt-like polyurethanes Starting materials listed.

The aqueous dispersions or colloidal solutions of these cationic Polyurethanes have particle sizes between approximately 0.10 and 100 µm. You can organic solvents also contain, for example, acetone or dimethylformamide. So you need that to produce the disDersion in accordance with the German interpretations 1 184 946, 1 178 586 and Belgian patent 653 223, respectively cannot be removed from the dispersion formed and, moreover, can also be high-boiling Use solvents such as dimethylformamide when preparing the dispersion.

Cationic polyurethanes are preferred for the process according to the invention, those made from higher molecular weight polyhydrocyl compounds with a molecular weight of 500 to 5000, Polyisocyanates, a basic chain extender with tertiary, preferably aliphatic substituted nitrogen atoms, such as 0B. N-Nethyl diethanolamine, N, N-bis (aminopropyl) methylamine, and optionally further non-basic chain extenders, such as preferably Dialcohols or diamines, water hydrazine or substituted uydrazines, are made. The polyurethane composition preferably contains 2 to 12% N-methyl diethanolamine. The tertiary nitrogen built into the polyurethane mass as a result 10 to 100% with an alkylating agent such as dimethyl sulfate, Methyl chloromethyl ether, diethyl sulfate or bromoethanol, quaternized and optionally the remaining tertiary nitrogen partially or completely with an acid such as hydrochloric acid, Lactic acid or acetic acid, neutralized in the presence of water.

Preferably find, at least partially, bi- or trifunctional Alkylating agents such as dibromobutane, p-xylylene dichloride, 1,3-dimethyl-4,6-bis-chloromethylbenzene, Methylene-bisbromoacetamide, trimethylolpropane-tris-chloroacetic acid ester and bi- or trifunctional acids with PK values below 4, such as phosphoric acid or sulfuric acid, each used as an aqueous solution, this initially being predominantly monofunctional react and then have a crosslinking function in the finished microporous fabric Exercise The cationic polyurethanes are generally used during their manufacture or then dispersed in water. For the purpose of later networking, the dispersed polyurethanes, of course, also incorporated e.g. methylol ether groups contain.

A suitable cationic dispersion in a dimethylformamide-water mixture can be made, for example, as follows: A hydroxyl-terminated polyester is reacted with a diisocyanate to form a prepolymer, with dimethylformamide diluted and further reacted with N-methyldiethanolamine. Then takes place the quaternization with dichlorodurene (1,4-bis (chloromethyl) benzene) and the addition of phosphoric acid and a mixture of equal amounts of dimethylformamide and water0 the The production of anionic polyurethane dispersions can be carried out according to known methods Procedure. Suitable anionic polyurethanes are, for example, in DAS 1 237 306, the DOS 1 570-556, the DÜS 1 720 639 and the DOS 1 495 847. It is used, analogously to the preparation of cationic dispersions, in addition to the usual glycols or diamines compounds which either have anionic groups contain or groups that are subsequently converted into anionic groups permit.

Such compounds are, for example, hydroxy and mercapto acids, such as Glyceric acid, citric acid or uric acid, amino acids such as diaminonaphthoic acid, Hydroxy and carboxysulfonic acids such as 2-hydroxyethanesulfonic acid or p-sulfobenzoic acid, also aminosulfonic acids such as hydrazine disulfonic acid, 2,4-diaminotoluenesulfonic acid- (5) or Aminoäthylaminoäthansulfonsäure, derivatives of phosphinic acid, phosphonous acids, Phosphonic acids and phosphoric acids, esters of phosphorous and phosphoric acid and their thio analogs, e.g. phosphoric acid bis-propylene glycol esters, and also hydrazinedicarboxylic acids and diamino-amide-carboxylic acids or their salts, such as sodium phthalate-bis-N, N (r-aminopropyl) amide.

You can also use in the preparation of the anionic dispersions Polyurethanes with free hydroxyl and / or amino groups go out and these with aliphatic or aromatic aldehydes and simultaneously or subsequently with a metal sulfite, metal hydrosulfite, metal amino carboxylate or metal amino sulfate realize. Finally, another option is to use polyurethanes with free Hydroxyl and / or amino groups with cyclic compounds with 3-7 ring members implement the salt-like groups or groups capable of salt formation after the ring opening (see DAS 1 237 306). These include in particular sultones, such as 1,3-propane sultone, 1,4-butanesultone or 1,8-naphthsultone, and lactones such as β-propiolactone or t -butyrolactone as well as dicarboxylic anhydrides, e.g. succinic anhydride, For cationic or anionic polyurethanes suitable for the process according to the invention can also be built up according to DOS 1,770,068 via a formaldehyde polycondensation will.

It uses higher molecular weight polyisocyanates with an excess to compounds with terminal methylol groups (e.g. amine-formaldehyde resins or Phenol-formaldehyde resins), disperses the reaction product containing methylol groups in water and finally cross-linked by heat treatment with the formation of methylene bridges.

It is also possible in the process according to the invention as coagulation regulators Use products as described in German Offenlegungsschrift No. 1 953 345, 1 953 348 and 1 953 349. These are aqueous dispersions of ionic emulsion polymers produced by free radical emulsion polymerization of olefinically unsaturated monomers in the presence of cationic or anionic Oligo- or polyurethanes are produced.

Particularly preferred according to the invention are those cationic or anionic polyurethanes that already have chemical crosslinking points at the time of their use and not afterwards like the dispersions described at the outset network.

The production of such crosslinked polyurethane particles is not Subject of the present invention. You can according to various, the specialist methods known in principle are carried out.

In general, crosslinked polyurethane particles can be used both as a suspension in suitable organic solvents or in water or even without assistance of a liquid medium. You can also use any of these procedures through the choice of suitable reaction components come directly to crosslinked particles or initially produce predominantly linear thermoplastic particles and then network them.

To prepare a suspension in an organic medium, selects you generally have such a solvent in which one or the other several of the reactants dissolve, but not the high molecular weight reaction product. In the course of the reaction in such a medium, the solution initially formed goes gradually into a suspension, this process being expediently carried out Stirring is supported. It is essential that the networking process only takes place after training the disperse phase begins, otherwise swelling occurs. You can also do that Use solvents which are still uncrosslinked but already high molecular Dissolve polyurethane in the heat, but not at room temperature. The suspension can then obtained from the solution by cooling with stirring.

The same effect can also be achieved by adding a non-solvent, however, the nonsolvent should be miscible with the solvent. Training a disperse phase with the desired particle size can be added by adding more suitable Dispersants are influenced.

For the production of finely divided polyurethanes in aqueous media are a variety of procedures are known. So you can for example the solution of a polyurethane in a water-immiscible solvent Disperse in water using an emulsifier and add the organic solution remove by distillation. A particularly preferred method is ionic and / or hydrophilically modified polyurethanes with or without solvents with water to mix, depending on the constitution and the reaction conditions Form polyurethane suspensions. A particularly preferred variant of this Process consists in using isocyanate or terminated polyurethane prepolymers Use methylol groups, using very high percentage solutions or can also work completely solvent-free. The coarse emulsions formed primarily go through reaction of the isocyanate groups with water or in the aqueous phase dissolved diamines or polyamines with chain extension and crosslinking in high molecular weight Polyurethane-urea suspensions over. The chain extension of methylol groups containing prepolymers can, for example, by heating or lowering the pH value can be achieved.

Also by injecting high molecular weight polyurethanes or their reactive ones Suitable suspensions can be made up of precursors in water or organic nonsolvents produce.

In principle, they are all used for the production of polyurethane dispersions or latices proposed methods for the production of polyurethane suspensions suitable, provided that care is taken that these suspensions do not settle through sedimentation or shear forces coalesce. This means that a not yet sufficiently high molecular weight Primary suspension should be kept moving until the dispersed Particles have become tack-free. To crosslink the dispersed particles can you either start from more than bifunctional starting materials, e.g. branched polyesters or polyethers, triisocyanates or triols at the Use the structure of the polyurethane (also) or an initially linear one, i.e. a bifunctional one NCO prepolymer made from components with higher functional amines into one implement cross-linked polyurethane urea. But you can also choose from purely bifunctional Components build up cross-linked particles by working under conditions that Cause branching, e.g. by adding catalysts, which trimerize the isocyanate or the formation of allophanate resp.

Favor biuret structures. In the presence of water and / or diamines often leads to the use of the existing hydroxyl or Amine compounds more than equivalent amounts of isocyanate to a crosslinking.

Linear high molecular weight polyurethanes can also be in the form of a suspension are subsequently crosslinked in a liquid medium or in powder form, e.g. by treatment with polyisocyanates or formaldehyde or formaldehyde-releasing Links. Products containing basic groups can, for example are crosslinked with polyfunctional quaternizing agents or acids, products, containing acidic groups with metal oxides or polyamines. For networking Polyurethanes which contain unsaturated double bonds are suitable, for example the known radical formers or sulfur, polymercaptans and others for Reaction with double bonds enabled at least bifunctional agents.

The solvent-free production of cross-linked polyurethane particles succeeds, for example, by pulverizing polyurethane elastomers, e.g. in a baffle plate grinder. It is particularly advantageous to use the elastomer directly in the To pulverize after its production, if it is already tack-free but has not yet fully reacted, so that it can be broken up without great expenditure of energy succeed.

A detailed description of the preparation of crosslinked ionic Polyurethane suspension can be found, for example, in German Auslegeschriften No. 1 495 745 (U.S. Patent 3,479,310), 1,282,962 (Canadian Patent No. 837,174), and 1,694,129 (British Patent No. 1 158 088) and German Offenlegungsschriften No. 1 595 687 (US Patent 3,714,095), 1,694,148 (U.S. Patent 3,622,527), 1,729,201 (British Patent No. 1 175,339) and 1,770,068 (U.S. Patent No. 3,756,992).

The special importance of chemically crosslinked ionic polyurethane suspensions for the process according to the invention is that it, as surprisingly has been found, in very many cases, it is possible to use such cationic or anionic ones Suspensions alone to produce satisfactory microporous sheet-like structures. The Ionic However, polyurethane suspensions must meet the following criteria: a) the suspension must sediment but be redispersible; b) particle size: 0.8 - 100 / u, preferably 2 - 50 c) the polyurethane must be chemically as extensive be networked so that it does not dissolve even in boiling DMF.

The advantage of this variant of the method according to the invention lies easy processing, since only a single coagulation regulator is added needs to become. For certain types of elastomers (when using carbodihydrazide as an Eette extender), however, the addition of cationic resp.

anionic suspensions alone are not sufficient in some cases (see example 3 *).

The use of combinations is therefore preferred according to the invention from cationic and anionic polyurethane dispersions. On the one hand, these lead to a bigger one Production security (especially in large-scale Scale), on the other hand, as discussed at the beginning, with a -related to polyurethane solids- A smaller amount of ionic groups will suffice. Furthermore In this case, dispersions other than those mentioned above can also be used Criteria must meet (e.g. those with a smaller particle size that are chemically are essentially uncrosslinked and are therefore still soluble in DMF).

The formulation of the elastomer solution can be in several ways take place. In many cases it is useful to use the nonionic elastomer solution and these one after the other with the cationic and / or anionic dispersion to mix homogeneously in any order with vigorous stirring, although Care must be taken that when using purely aqueous ionic polyurethane dispersions this beforehand with a water-miscible solvent such as dimethylformamide or dimethyl sulfoxide, must be added to the addition to the elastomer solution avoid local coagulation. It is also possible to do the opposite to mix charged dispersions very intensively, the precipitated polyurethane (urea) salt to remove the low molecular weight ionic constituents on a suction filter, then taken up in an organic solvent and the gel obtained as a Stir coagulation aid into the non-ionic elastomer solution. When applied In the last-mentioned method, the coagulation bath does not contain any low molecular weight Compounds, which is beneficial for the recovery of the organic solvent is.

You can also use cationic or anionic polyurethane (urea powders go out. The powders are made into a paste with a solvent as described above and then stirred into the elastomer solution in gel form, creating a suspension.

In a special embodiment of the method according to the invention, the cell stabilizers and cell regulators used are polyurethane (ureas) containing polysiloxane groups or ionic polyurethane (urea) dispersions which form the structural unit contain. In the formula> 2, preferably a number between 5 and 100, Z = C1-C5-alkyl- 'C6 C15-aryl, siloxyl or siloxanyl radicals, preferably a methyl group, or where the groups Z can all be the same or else different, but preferably only one of the substituents Z connected to a Si atom is the group represents, R = an alkylene radical optionally containing heteroatoms and Y = -NH-, -0- or -S- The siloxane group content of the microporous polyurethane film is preferably 0.1 to 20 wt , 5% by weight.

It is essential that the siloxane groups have carbon bridges, for example according to the formula are chemically built into the polyurethane.

Such polyurethane-polysiloxanes are in the German Auslegeschriften 1 114 632, 1 190 176 and 1 248 287. Base product for their manufacture are organo-polysiloxanes which have at least one, preferably two, bonded to silicon. carbofunctional groups with isocyanate-reactive hydrogen atoms contain. the carbofunctional groups are preferably aliphatic, optionally containing heteroatoms, hydrocarbon radicals with 1 to 6 carbon atoms, the at least one hydroxyl, carboxyl, mercapto or primary or secondary Have amino group.

The organopolysiloxanes can be obtained by known processes. For example the particularly suitable hydroxymethylpolysiloxanes can be obtained by direct reaction of bromomethylpolysiloxanes with alcoholic potassium hydroxide solution. 4-aminobutylpolysiloxanes are produced via the hydrogenation of the easily accessible nitriles, corresponding Carboxyl derivatives by saponification of the cyanoalkyl silicon compounds. Aminomethylsiloxanes are by amination of the halomethylsilicon compounds with ammonia or primary amines obtained.

In many cases, the functional groups are initially attached to low molecular weight Siloxanes introduced; the products obtained in this way are then used by the well-known Equilibration reaction converted into higher molecular weight polysiloxanes.

Polysiloxanes with at least 2, preferably 5-100, siloxane groups are preferred and with a molecular weight of 194 to 20,000, preferably between 500 and 6,000. Aqueous polyurethane-polysiloxane dispersions can also consist of polyfunctional Organo-polysiloxanes are produced.

Such organo-polysiloxanes are for example in the French Patent specification 1 291 937 and in the German Auslegeschrift 1 114 632 described.

The polymer solutions can also without affecting the coagulation behavior is adversely affected, contains additives, e.g. polyvinyl chloride and its copolymers, Polyacrylonitrile and its copolymers, carboxymethyl cellulose, polyalkyl (meth) acrylates, Emulsifiers, optical brighteners, antioxidants, special light protection agents such as N, N-dialkyl hydrazides, crosslinking substances such as paraformaldehyde, melamine hexamethylol ether or other formaldehyde derivatives, polyisocyanates, quaternizing agents or polyaziridine ureas and dyes, suitably insoluble pigments.

Although not essential, an additional influence can be used on the coagulability of the polyurethane solutions by adding nonsolvents, preferably water, are applied to the coagulable polyurethane systems.

The highest possible amount of non-solvent is reached when the polyurethane begins to fail. Also by using the ionic polyurethane dispersions nonsolvents (water) can be brought into the system. In this case, too you can also add nonsolvents. Generally this will be nonsolvent not in pure form but added in a mixture with solvent, e.g. in the form a dimethylformamide / water mixture. The total content of the coagulable mixture of nonsolvents should be about 9 percent by weight, preferably 6 percent by weight, generally do not exceed.

The use of the additives according to the invention in particular together with the polyurethane-polysiloxanes described above, however, has the great advantage that on an accurate dosage of the amount of nonsolvent, for example in the case of pre-gelation on a movable surface by means of water vapor, like them was necessary in the process of the prior art can be dispensed with. The composition of the coagulation bath is also of minor importance Meaning. In this way, products with excellent properties are also obtained if polyurethane solutions with the coagulation regulators according to the invention without the addition of nonsolvents be coagulated directly in water.

For the continuous production of microporous fabrics one brings the mixture of polyurethane solution, cationic and / or anionic Polyurethane dispersion or optionally polyurethane polysiloxane on a porous or non-porous substrate, e.g. by brushing on, pouring on or squeegeeing the applied layer, if necessary, a treatment room with a water vapor atmosphere happen, whereby gelation occurs to a film and then passes the material through Coagulation, washing and post-treatment baths, the last of which is an alcohol bath can be.

The microporous sheet-like structure is then dried.

The applied layer thickness depends on the desired final thickness the microporous fabrics. Usually layer thicknesses of the applied Polyurethane mixtures from 0.5 to 1.5 mm are sufficient. A porous substrate you will choose if these are coated directly with the polyurethane compound target. As porous substrates zoBo fabrics, knitted fabrics, fleeces or felts can be mentioned. However, random fiber fleeces with the polymer solution mixtures can also be microporous be bound.

A non-porous substrate, e.g. a glass plate, a metal tape (possibly with structured surface) or one with plastics, e.g. perfluoropolyethylene, coated fabric sheet is used when porous polyurethane films are desired which are removed by the reverse process and transferred to other water-vapor-permeable Transfer substrates, e.g.

should be glued on. Suitable substrates are, for example, Split leather, cardboard, paper or woven and non-woven textile fabrics.

The determination of the water vapor permeability in the examples was carried out by the method of I UP 15, given in "Das Leder", 1961, pp. 86-88, which describes the water vapor permeability in delivers (measurement at normal pressure and a relative humidity of 65% at 20UC). The tear strength, elongation at break and the moduli and other elasticity values on the microporous films were determined in the manner known per se.

The strength values of the microporous films are naturally in general the lower, the greater the water vapor permeability is0 Even with the same The respective strength properties still depend decisively on water vapor permeability on the quality and uniformity of the microporous structure, which is caused by the applied coagulation process is determined. There is a special value in the The method according to the invention is that uniformly microporous films with good Surface, temperature resistance, high strength values and against others Process significantly improved abrasion properties with high permeability can be obtained, while at the same time dispensing with a defined nonsolvent additive the procedure can be shortened in terms of time.

The following examples and comparative examples illustrate the advantages of the method according to the invention.

1) Preparation of the elastomer solutions Product 1.1 A prepolymer from 1,240 parts by weight of polyester A and 310 parts by weight of 4,4'-diphenylmethane diisocyanate is diluted with a total of 4,700 parts by weight of dimethylformamide and with 50 parts by weight Carbodihydrazide reacted in 100 parts by weight of water. The 25% elastomer solution has a viscosity of about 25,000 - 50,000 cp at 25Or.

Polyester A: from adipic acid and ethylene glycol / 1,4-butanediol (molar ratio 1: 1); OH number 56, acid number 1.

Product 1.2 An elastomer granulate, which by melt phase polyaddition was produced at 110-140 ° C from the following components: 50 parts by weight polyester A 50 parts by weight of polyester B 48 parts by weight of 4,4'-diphenylmethane diisocyanate 13 parts by weight 1,4-Butanediol is dissolved in 25% strength at 50 ° C. in dimethylformamide. You get one homogeneous solution with a viscosity of 15,000 - 60,000 cp.

Polyester B: hexanediol-1,6-polycarbonate; OH number 56, acid number 1.

2) Preparation of the cationic polyurethane suspensions Product 2.1 900 parts by weight of polyester C are mixed with 231 parts by weight of tolylene diisocyanate at 70-75 ° C. (2,4- / 2,6-isomer mixture in the ratio 65/35) reacted for 2 hours and that Prepolymers diluted at 50 ° C. with 756 parts by weight of dimethylformamide. After that will be 91 parts by weight of N-methyldiethanolamine and, after a further 30 minutes, 24.5 parts by weight Dichlordurol added in 150 parts by weight of dimethylformamide. The Quaternization Reaction is finished after 1 hour at 500C.

Then 24 parts by weight of 90 goat phosphoric acid in 100 parts by weight Water, 880 parts by weight of dimethylformamide heated to 50 ° C. and 1070 parts by weight Water at 30 ° C. was added. After stirring for half an hour, the approx. 28% by weight Cool the dispersion containing solids.

Polyester C: from adipic acid / phthalic acid (molar ratio 1: 1) and ethylene glycol; OH number 62, acid number 1.

Product 2.2 960 parts by weight of polyester C become 228 at 100-1100C Parts by weight 1,6-hexamethylene diisocyanate reacted for 2 hours with stirring and on 50 ° C., then 28.4 parts by weight of N-methyldiethanolamine and after 30 minutes 29.6 parts by weight of dimethyl sulfate in 150 parts by weight of dimethyl formamide were added.

The prepolymer becomes 1096 parts by weight after a further 15 minutes Dimethylformamide diluted at 50 ° C and brought to room temperature. NCO content of Prepolymers: 2.56%.

The 50% prepolymer solution is mixed with vigorous stirring at 18-25 0C with 270 parts by weight of 18.1% aqueous diethylenetriamine solution with the addition of 2060 parts by weight of dimethylformamide / water (weight ratio: 55:45) reacted and stirred for a further 3 hours.

The sedimenting, but redispersible suspension consists of 27% by weight solids, 50% DMF and 23% water.

3) Production of anionic polyurethane suspensions Product 3.1 (Aliphatic type) 5200 parts by weight of a proprietary prepolymer solution of polyester C and 1,6-hexamethylene diisocyanate in dimethylformamide (NCO content = 3.72%) with vigorous stirring at 20 ° C. with 1403 parts by weight of a 23.8 show aqueous Solution of ß-Aminoäthyl-aminoäthansulfonsaurem sodium and 223 parts by weight of a 13% strength aqueous solution of diethylenetriamine in 1634 parts by weight of dimethylformamide-water mixture (Weight ratio 48/52) implemented.

The sedimenting, but redispersible suspension contains 35% Solid, 25% water and 40 5 'DMF.

Product 3.2 (Aromatic Type) 4,885 parts by weight of a 50% DMF prepolymer solution (NCO content 3.46%) from 8,000 parts by weight of polyester C and 2,400 parts by weight of tolylene diisocyanate (2,4-: 2,6- isomer mixture 80:20) are mixed with a 20% strength aqueous solution of 1 125 parts by weight of diethylenetriamine and 327 g of Aminoä (thylaminoäthansulfonsaurem sodium (Amine equivalent ratio 4: 1) in 1,620 parts by weight of dimethylformamide / water (weight ratio 32:68) to a sedimenting, but redispersible PUR suspension as in Product 3.1 described implemented. The suspension contains 35% solids, 40% DMF and 25% water.

4) Preparation of the polyurethane urea salts The cationic dispersion is presented at room temperature and the anionic suspension with vigorous stirring slowly entered. When the phases separate, the mixture is homogenized with dimethylformamide. After stirring for a further 1 hour, the polyurethane salt is added in approximately the same amount Methanol / water (ratio 1: 1) precipitated. The polyurethane salt is after complete Suck off precipitation (1-3 hours), washed several times with small portions of methanol and the moist filter cake was immediately taken up in dimethylformamide. The gel-like Polyurethane (urea) salt can be used directly as a coagulating aid at any point in time be suspended in a polyurethane elastomer solution.

Product 4.1 from cationic dispersion 2.2 and anionic suspension 3.1 Solid content 15% water content 7% content DMF / CH3OH 78% ion ratio Cations: Anions 5: 1 product 4.2 from cationic dispersion 2.2 and anionic Suspension 3.2 Solids content 11.5% Water content 6.5% DMF / CH3OH content 82.0% Ion ratio of cations: anions 3: 1 5) Production of the polyurethane (urea) polysiloxanes Product 5.1 Nonionic polysiloxane made from: 125.00 parts by weight polyester D 25.15 Parts by weight of hexamethylene diisocyanate 96.15 parts by weight of organofunctional siloxane (Formula I), OH content 2.7% by weight, M = 1250.

(39.1% by weight, based on total solids) 246.30 parts by weight of dimethylformamide (NCO: OH ratio - 1.00) The presented in a stirred tank, dehydrated polyester is at 1000C with hexamethylene diisocyanate for 30 minutes implemented. The NCO content is then 4.3% (theoretical 4.26%).

The total amount of organofunctional polysiloxane is also at 100 ° C stirred in and reacted for 3 hours. After half an hour the reaction mixture is gradually homogeneous.

NCO content of the reaction mixture: after 60 minutes 0.25% by weight, after 120 minutes 0.15% by weight, after 180 minutes 0.02% by weight.

After 3 hours, the reaction is practically complete.

It is then diluted with dimethylformamide in 3 portions (1: 2: 2) and stirred for 1 hour. DS viscosity of the fully reacted 50% solution is at 25 0C 5,000 cp to 10,000 cp.

PolyesterD: from hexanediol / neopentyl glycol (1: 1) and adipic acid (OH number 66, acid number 1).

Siloxane Product 5c2 Anionic polyurethane urea polysiloxane First, a 50,000 prepolymer solution (NCO content 3.8%) of 960 parts by weight of polyester D 300 parts by weight of 1,6-hexamethylene diisocyanate 60 parts by weight of organofunctional siloxane (formula I ), OH content 3.2% by weight, M = 1060, and 1320 parts by weight of dimethylformamide. This prepolymer is then mixed with vigorous stirring at 20 ° C. with 794 parts by weight of a 21.8 parts by weight of an aqueous solution of ß-Aminoäthylaminoäthansulfonsaurem sodium and 111 parts by weight of a 14.4% aqueous solution of diethylenetriamine in 770 parts by weight. Parts of dimethylformamide / water (ratio 57:43) extended.

Product 5.3 Cationic polysiloxane-polyurethane from 24.3 parts by weight Polyester C 6.08 parts by weight of hexamethylene diisocyanate 0.758 parts by weight of N-methyldiethanolamine 0.795 parts by weight of dimethyl sulfate and 13.6 parts by weight of organofunctional siloxane (Formula I), OH content: 2.7% by weight, M = 1250.

(29.9% by weight based on total solids).

The polyester is dehydrated for 30 minutes at 130 ° C under vacuum and then added the hexamethylene diisocyanate at 1000C.

After a reaction time of one hour at 100 ° C., the isocyanate content is 6.20% (theor. 6.05).

After cooling to 60 ° C., the methyl diethanolamine is stirred in and reacted for one hour at this temperature. Then with 18.4 parts by weight Diluted dimethylformamide and, after a further 10 minutes, the dimethyl sulfate dissolved in 1.2 parts of DMF.

This is followed by another addition of 12.4 parts of dimethylformamide at 600C. After reaching the theoretical isocyanate content (2.05) the organofunctional Stirred in siloxane and completely implemented at 60-70 ° C.

The viscosity of the finished solution is 4,300 cp. The solution can can be diluted with any amount of water.

6) Making the microporous films.

The polyurethane (urea) solution heated to 50-80 C (viscosity of the 22% solution at 250C: 10,000-30,000 cp) is mixed in portions with the coagulating aids added and evenly suspended by vigorous stirring. Before coagulation the formulation is degassed under vacuum until the air that has been stirred in is completely removed is.

The bubble-free formulation is placed on a glass plate or

a movable 2 m wide steel belt applied and with a doctor blade set to a thickness of about 1.5 mm. The coating is then through a Pre-gelation zone and there the action of moist air (30-70% relative Humidity: 50-980C). After that, the steel belt is placed in a water bath guided and thereby the film finally coagulated. The slide is washed and dried in a heating zone at approx. 1000C.

Using the same principle, a cotton fabric is used in Examples 6 * and 9 coated directly. The physical. Values relate onto the linerless microporous film.

The coagulated films or coatings have a thickness of 0.33 + 0.03 mm.

The results of the experiments are summarized in the following table.

Explanations: The examples marked with * are intended as comparative examples to grasp. The amounts given are parts by weight, based on solids.

Tanigan is a phenol-formaldehyde condensate with sodium sulfonate groups. “Loss of solids” means the amount of substance washed out during coagulation. "Area shrinkage" is the difference between the areas of the elastomer solution applied with a doctor blade and dried foil.

The buckling strength was determined on a Balli flexometer.

Wdd = water vapor permeability. Serial no. Elastomer ionic PUR PUR salt PUR poly tanigan solid Solution cationic anionic siloxane loss 100 wt. (%) Parts 1 * 1.1 25 pieces - - - - - 2.1 2 * 1.1 37 pieces - - - - - 2.1 3 * 1.1 - 37 parts 3.1 - - - - 4 * 1.1 25 pieces - - - 6 6.5 2.1 5 * 1.1 20 pieces - - - 5 16.5 2.1 1 1.1 25 parts 6 parts - - - 0.4 2.1 3.1 2 1.1 25 parts 6 parts - 0.6 parts - 0 2.1 3.1 5.1 3 1.1 25 parts 2.1 - - 6 parts 5.2 - 0 4 1.1 - 6 parts 3.1 - 25 parts 5.3 - 0 5 1.1 20 parts 5 parts 3.2 - - - 0.3 2.1 6 1.1 25 parts 6 parts 3.2 - - - 0.4 2.1 7 1.1 - - 25 parts - - 0.4 4.1 8 1.1 - - 25 parts - - 0.2 4.2 6 * 1.2 17 parts 2.1 - - - - 7.5 9 1.2 - - 17 Parts 4.1 - - 0.2 Area Tensile strength fracture Wdd Serial no. shrinkage fracture Elongation mg / cm2h Remarks (%) Balli-Flex. (kp / cm) (%) 1 * 41 - - - 0 homogeneous film 2 * 43 - - - 0 hompgene foil 3 * 40 - - - 0 homogeneous film 4 * 18 - - - 8 irregular surface 5 * 26 - - - 3 only partially microporous 1 11> 200 000 98 595 11 good pore structure 2 9> 200 000 122 520 15 uniformly fine-pored 3 10> 200 000 140 490 14 uniformly fine-pored 4 11> 200 000 119 515 12 uniformly fine-pored 5 12> 200 000 130 650 14 good pore structure 6 11> 200 000 117 610 17 good pore structure 7 9> 200 000 116 615 14 very good pore structure 8 8> 200 000 140 630 14 very good pore structure 6 * 15> 200 000 - - 7 irregular surface 9 8> 200 000 102 540 15 uniformly microporous Example 10 a) Production of a cationic, crosslinked polyurethane-urea suspension.

79.5 mol of polyester C are dewatered for 30 minutes in a vacuum at 130 ° C, then 1 hour at 100 ° C. with 138 mol of toluene diisocyanate (mixture of 2,4 / 2,6 isomers in a ratio of 65 to 35) and 177 mol of 1,6-hexamethylene diisocyanate and then stirred the product cooled to 60 0C. There is now a solution of 37.8 mol of N-methyl diethanolamine added in 13.5 kg of acetone, the mixture stirred for a further hour at 60 0C and diluted with 32 kg of acetone.

The prepolymer is stable on storage for a few days.

Before dispersing, the prepolymer is quaternized with 35 mol of dimethyl sulfate diluted to 50% with acetone. The NCO content is thereafter about 4.4 wt.

The dilute ionomer solution is stirred vigorously at 15 to 30 ° C reacted with an aqueous solution of diethylenetriamine (equivalent ratio NCO / NH2 = 1.10), then at bath temperatures of about 80 C while passing in Nitrogen distilled off the acetone.

The aqueous dispersion is after decanting off the serum with dimethylformamide added and the water partially removed by distillation in vacuo.

The resulting redispersible, cationic suspension has a mean particle size of about 10-20 / u.

and consists of 28.6% by weight solids, 43.9% by weight DMF and 27.5% by weight Water.

b) Preparation of an anionic, crosslinked polyurethane urea suspension.

Analogously to a), a 50% prepolymer (3.55% by weight NCO) is obtained 89.5 moles of polyester C and 250 moles of 1,6-hexamethylene diisocyanate with a mixture of diethylenetriamine and ß-aminoethylaminoethane sodium sulfonate at NCO / NH2 = 1.04 implemented (the equivalent ratio between triamine and diaminosulfonate is with 1: 2.

A storage-stable, redispersible, anionic dispersion is obtained from 28 wt .-% solids, 44.5 wt .-% DMF and 27.5 wt .-% water with an average Particle diameter of 5 - 10 / u.

c) Preparation of the elastomer solution.

By melt phase polyaddition at 110 to 140 C it becomes an elastomer granules made from the following components: 50 parts by weight polyester A 50 parts by weight Polyester B 48 parts by weight of 4> 4 -diphenylmethane diisocyanate 13 parts by weight of 124-butanediol That At 50 ° C., 25% of the elastomer is dissolved in dimethylformamide. A homogeneous one is obtained Solution with a viscosity of 15,000 to 60,000 cP.

d) Production of the microporous films.

The polyurethane urea solution, heated to 50 to 80 ° C., is added in portions the suspensions a) or b) are added and the mixture is homogenized by vigorous stirring. The solids ratio between nonionic elastomers and ionic polyurethane urea is 4 to 1.

Before coagulation, the very storage-stable formulation is placed in a vacuum degassed until the air that has been stirred in is completely removed.

The bubble-free formulation is placed on a glass plate or a movable one 2 meter wide steel strip applied and with a squeegee to a thickness of approx. 1.5 mm set. The coating is then passed through a pre-gel zone and there the action of moist air with 50% relative humidity Exposed to 60 ° C. The coated steel strip is then placed in a water bath and thereby the film finally coagulates. The foil is washed and in one Heating zone dried at approx. 1000C.

The coagulated films or coatings have a thickness of 0.33 + 0.03 mm.

With both crosslinked polyurethane urea suspensions a) and b) are Get microporous fabrics that when tested on the Balli-Flexometer a Have a buckling strength of more than 200,000. The water vapor permeability the cationically coagulated film is 6 mg / cm2.h, that of the anionically coagulated film Film at 2 mg / cm2.h The formulations according to Example 1.0 can be carried out in an analogous manner also applied to a textile substrate and then coagulated in a water bath will.

Claims (4)

Claims 1) Process for the production of microporous, water vapor permeable Flat structures through coagulation of hygroscopic polyurethane (urea) solutions, characterized in that the polyurethane (urea) solutions -before coagulation Suspensions of cationic and / or anionic polyurethane (ureas) s added will. 2) Method according to claim 1, characterized in that the polyurethane (urea) contain suspensions nonionic or ionic polyurethane-polysiloxanes. 3) Method according to claim 1 and 2, characterized in that cationic and anionic polyurethane dispersion before adding to the polyurethane (urea) solution are mixed together. 4) Method according to claim 1 and 2, characterized in that suspensions of cationic and / or anionic polyurethane (ureas) s are used, which a) sediment and are redispersible, b) a particle size of 0.8 - 100 / u and c) are insoluble in boiling DMF.