DE4013546A1 - USE OF ACETIC ACID ESTERS IN THE PRODUCTION OF POLYURETHANE DISPERSIONS - Google Patents

Abstract

The description relates to the use of propane diols and/or triol esterified with acetic acid as viscosity-regulating, non-reactive components in the production of storable aqueous polyurethane dispersions by processes known per se. The acetic acid esters are eminently suitable as replacements for the solvants used in the long-known processes.

Description

The invention relates to the use of esterified with acetic acid Propanediols and / or triols as viscosity regulating, non-re active component in the production of aqueous storage-stable Polyurethane dispersions by methods known per se.

The skilled person is familiar with aqueous polyurethane dispersions and processes their manufacture known from the prior art. Suitable Her adjusting methods for polyurethane dispersions are such. B. in D. Diete rich, Angew. Macromol. Chem. 98, p. 133 (1981), Ullmann, Encyklo Pedagogy of Technical Chemistry, 4th Edition, Volume 19, Verlag Chemie, Weinheim / Bergstraße 1974, pp. 311-313, Houben-Weyl, methods of or Ganische Chemie, Volume E 20 / Teil 1-3, pp. 1659-1663 and pp. 1671-1681 and in the Journal of Waterborne Coatings, August 1984, pp. 2 ff wrote. From the secondary literature mentioned in these articles The inclined expert can also face the corresponding one  Open up patent literature. They are also exemplary here Called DE 29 31 044 and DE 36 13 492.

Of particular importance are the so-called acetone Process and the prepolymer-ionomer mixing process. The one after these Processed polyurethane dispersions find a wide range Area of application, starting from household all-purpose adhesives (EP 3 54 471), as an aid for the textile and leather industry, for coatings such as e.g. B. Base coatings for metallic automotive paints (EP 89 497) for paper coating (DE 24 00 490, DE 24 57 972).

Methods for the production are known to the person skilled in the art from the patent literature of polyurethane dispersions e.g. B. from DE 15 95 602 known. A newer process for the production of polyurethane dispersions is in DE 36 03 996 and the state of the art specified therein, namely: DE-PS 8 80 485, DE-AS 10 44 404, US-PS 30 36 998, DE-PS 11 78 586, DE-PS 11 84 946, DE-AS 12 37 306, DE-AS 14 95 745 DE-OS 15 95 602, DE-OS 17 70 068, DE-OS 20 19 324, DE-OS 20 35 732, DE-OS 24 46 440, DE-OS 23 45 256, DE-OS 24 27 274, US-PS 34 79 310 and Angewandte Chemie 82, 53 (1970) and Angew. Macromol. Chem. 26.85 ff. (1972).

Of the processes mentioned, the "acetone process" in particular in analogy to the teaching of DE-OS 14 95 745 (= US-PS 34 79 310) or to DE-OS 14 95 847 (GB-PS 10 67 788) of importance. Here will generally a prepolymer with MCO end groups provides, which is then dissolved in an inert solvent is what the chain extension may be in solution to the higher molecular weight polyurethane.

The solvents used in the so-called acetone process additions of low boilers such. B. acetone u. a. necessary to  to lower the viscosity of the prepolymer and thus handle it to make bar, which makes a subsequent dispersion possible becomes. The disadvantage of such manufacturing processes is under consideration consideration of the mostly existing demand for solvents free products that a technically complex distillation step must be connected to the dispersion process to the low to remove boilers such as acetone at least predominantly. This means tet an additional process step, which is not the process only complicated, but also to make the product more expensive leads. This is not least because the preferred one Acetone cannot be easily recycled back into the process can, since anhydrous acetone is preferably used. Thus poses for the expert the question of whether and if so up to what amount of residual solvent is acceptable because of that Procedural effort depends. To meet the demand for a completely solvent-free product manufactured by this process a comparatively high effort is necessary.

The production of polyurethanes according to the prepolymer-ionomer mixture process generally leads to self-emulsifying high-molecular weight molecules ren polyurethanes. For example, a suitable polyol component with a suitable isocyanate component and one for Component capable of salt formation such as dimethylolpropionic acid and optionally a chain extender such as short chain di ole or diamines. The salt formation is said to be Component contained in an amount that the self-emuls Greedability of the resulting polyurethane prepolymer ensured is.

Almost all processes for the production of aqueous polyurethane disper sions have in common that before the final dispersion step of the self-dispersing polyurethane melt contains unreacted free isocyanate groups. These can be found at  or after the dispersing step for a further molecular gene weight gain, for example by chain extension with diamines, Diols or water can be used. So with the prepolymer ionomer Mixing process the resulting polyurethane prepolymer z. B. at the so-called two-reactor process at low temperatures in Water is stirred in so that the dispersing process is completed, before an appreciable isocyanate / water reaction can take place. In this manufacturing process, instead of the low-boiling orga African solvents high-boiling solvents, mostly N-methyl pyrrolidone. These solvents remain after the dis purging step in the polyurethane dispersion and usually show has a content of about 1 to 10% by weight.

In the melt emulsification process, however, the water becomes a polyure thanpolymer melt in the so-called one-reactor process give. This process, because of the high viscosity of the melt is usually carried out at 50 ° C to 70 ° C, however hitherto limited to polyurethane prepolymers whose isocyanate group pen are bound to tertiary carbon atoms. With a new kind of hot dispersion method according to the German application with the Case number P 40 11 430.9 this restriction is lifted. Also Low may also be used in these processes boilers such as acetone are removed by distillation, while optionally used high boilers such as N-methyl-pyrrolidone in the dispersion remain.

Suitable solutions for the production of polyurethane dispersions means are, for example, in DE 23 44 135 and in DE 34 38 563 called. These are connections or Classes of compounds that belong to the solvents in the narrower sense can be counted, d. H. they have undesirable properties on, are easily flammable, can be explosive Vapors develop, are carcinogenic or become suspect of it  tig and / or are not physiologically harmless. This applies ins special also for the z. B. in DE 34 38 563 preferred solution medium acetone and N-methyl-pyrrolidone. So z. B. in the for 1988 List valid in the Federal Republic of Germany for maximum ar workplace concentrations (MAK) for N-methyl-pyrrolidone a value of 100 ppm and for acetone of 1000 ppm. Furthermore can the solvents remaining in the polyurethane dispersion the application properties of the dispersion, for example adversely affect their storage stability and / or viscosity.

Against this technological background, the inventor Task to provide solvent substitutes instead of previously known solvents used in the manufacture of aqueous polyurethane dispersions by processes known per se can be used. These substitutes are said to be on the one hand both procedurally suitable, d. H. non-reactive and viscous regulate the crime, on the other hand, the aforementioned should not desired properties of the solvent in the substitute is not be present or significantly reduced.

The task was solved by using acetic acid esterified propanediols and / or triol as viscosity regulators de, non-reactive component in the manufacture of aqueous la gel-stable polyurethane dispersions according to known process ren.

Propanediols and triol esterified with acetic acid are known to the person skilled in the art known. They can be made theoretically or practically are by esterification of propanediols or triol with acetic acid re. Such esterification reactions are part of the basic knowledge of Chemist and are described in each textbook. The reaction is by catalysts e.g. B. proton donors favored. A return action (saponification) by shifting the chemical equilibrium  weight can be avoided by circles of water. From the propane diols Both 1,3-propanediol and 1,2-propanediol are the same moderately suitable. Propanetriol is also known as glycerin. Prefers are the products completely esterified with acetic acid. However esters are also suitable in which the acetic acid at least partly by other carboxylic acids with up to 6 carbon atoms each is replaced. Glycerin fully esterified with acetic acid also called glycerol triacetate or triazetin and is used in the sense of Invention preferred. This substance is commercially available and readily available in larger quantities.

The acetates mentioned are excellent substitutes for previously common and known solvents in the manufacture of aqueous polyurethane dispersions. You are opposite the reactants on which the polyurethane polymers are based are not reactive. Leave the propanediols and / or triol esterified with acetic acid yourself with no great difficulty instead of being from yourself known processes, in particular instead of those from the acetone, Melt emulsifying or prepolymer-ionomer mixing processes, known Use solvent. One advantage is that the Use of the esters mentioned as substitutes for the solvents the other process parameters were not changed or were not significantly changed Need to become. In preferred cases, the procedure is such that in the processes known per se, in particular in the prepolymer Ionomer mixing process, instead of the known high-boiling solution medium about the same amount of propane esterified with acetic acid diols and / or triol is used. Instead of the known low boiling solvent is used in the processes known per se, especially in the acetone process, about half to a third the amount of solvent used on the esters mentioned.

Glycerol triacetate or tri is particularly preferred as a substitute azetin. This substance is preferred, among other things, because it  is not a dangerous good, not a dangerous substance under the Chemicals Act and therefore does not need to be labeled in preparations. The known methods are through the use of triacetin instead the known solvents immediately and without major problems on the converting the method according to the invention, not least because because triazetin is available inexpensively in large quantities.

The starting point suitable for the production of polyurethane dispersions substances such as polyols, isocyanates, chain extenders, reactive components capable of salt formation as an internal emulsifier and Further auxiliary substances can be found in the patent mentioned above remove ten. Supplementary in this context is also the EP 3 54 471 and on DE 39 42 681 as well as on the already ge called German application P 40 11 430.9 pointed out.

Suitable polyols are, for example, polyester, polyacetals, poly carbonates, polyethers, polythioethers, polyamides and / or polyesters amides, which preferably each have an average of 2 to at most 4 hydroxyl have groups, the molecular weight between 300 and 20,000, preferably between 400 and 6000.

Polycarbonates are understood to mean polyesters that theoretically by esterifying the carbonic acid with di- or polyvalent alcohol fetch can be displayed, and at both ends of the chain have a hydroxyl group. The alcohols and ultimately the polycarbonate diols also have an aliphatic structure own construction. Suitable polyhydric alcohols can e.g. B. trivalent be like glycerin. However, divalent Al be kohole, especially if these are not less than four and have no more than ten carbon atoms. Cyclic and branched While alcohols are suitable, linear alcohols are often used prefers. The hydroxyl groups can be adjacent, e.g. B. in 1,2ths lung, or be arranged isolated. Mostly preferred  Diols with terminal OH groups. Suitable polycarbonate diols can a molecular weight of 500 to 8000, in particular from 800 to 2500 exhibit.

As polyethers such. B. the polymerization products of ethylene oxides, propylene oxide, butylene oxide and their mixing or graft polymerization products as well as condensation of more term alcohols or mixtures thereof and those by alkoxylie tion of polyhydric alcohols, amines, polyamines and amino alcohol fetch recovered polyether called. As polyethers are also in of said EP 3 54 471 described polytetrahydrofurans as well Suitable ethylene glycol-terminated polypropylene glycols.

As polyacetals such. B. from glycols such as diethylene glycol, Triethylene glycol, hexanediol and formaldehyde-producible verb in question. Also leave by polymerizing cyclic acetals produce suitable polyacetals.

Among the polythioethers are, in particular, the condensation pro products of thiodiglycol with itself and / or with other glyco len, dicarboxylic acids, formaldehyde, aminocarboxylic acids or aminoal alcohols listed. Depending on the co-components it is at the products around polythioethers, polythio mixed ethers, polythioethers esters, polythioether ester amides. Such polyhydroxyl compounds can also in alkylated form or in a mixture with alkylation means are applied.

These include the polyesters, polyester amides and polyamides polyvalent saturated and unsaturated carboxylic acids or their Anhydrides and polyhydric saturated and unsaturated alcohols, Amino alcohols, diamines, polyamines and their mixtures NEN, mostly linear condensates, e.g. B. Polyterephthalates. Also Lactone polyester e.g. B. caprolactone or from hydroxycarbon  acids can be used. The polyesters can be hydroxyl or carbo have xyl end groups. To build it as alcohol compo nente also higher molecular weight polymers or condensates, such as. B. Polyethers, polyacetals, polyoxymethylenes (with) can be used.

Polyhydro already containing urethane or urea groups xyl compounds and - optionally modified - natural Polyols such as castor oil can be used. Basically come too Polyhydroxyl compounds which have basic nitrogen atoms, in question, e.g. B. polyalkoxylated primary amines or polyesters or Polythioethers containing alkyl diethanolamine condensed. It is also possible to use polyols which are complete or partial ring opening of epoxidized triglycerides with primary or secondary hydroxyl compounds can be generated (DE 32 46 612), for example the reaction product of epoxidier soybean oil with methanol. Copolymers of the poly mentioned Hydroxyl compounds can be suitable, as can their analogs with preferably terminal amino or sulfide groups.

Suitable polyisocyanates are all multifunctional, aromatic and aliphatic isocyanates, such as. B. 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diiso cyanate, di- and tetraalkyldiphenylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, the Isomers of tolylene diisocyanate, optionally in a mixture, 1- Methyl-2,4-diisocyanato-cyclohexane, trimethylhexane diisocyanates such as 1,6-diisocyanato-2,2,4-trimethylhexane and 1,6-diisocyanato-2,4,4- trimethylhexane, chlorinated and brominated diisocyanates, phosphorus containing diisocyanates, 4,4'-diisocyanatophenylperfluoroethane, tetra methoxybutane-1,4-diisocyanate, hexane-1,6-diisocyanate, dicyclohexyl methane diisocyanate, cyclohexane-1,4-diisocyanate, ethylene diisocyanate, Bis-isocyanatoethyl phthalate, also polyisocyanates  reactive halogen atoms, such as 1-chloromethylphenyl-2,4-diiso cyanate, 1-bromomethylphenyl-2,6-diisocyanate, 3,3'-bis-chloromethyl ether 4,4'-diphenyl diisocyanate, tetramethylxylene diisocyanate, iso phorone diisocyanate. Sulfur-containing polyisocyanates are obtained from for example by reacting 2 mol of hexamethylene diisocyanate with 1 mol Thiodiglycol or dihydroxydihexyl sulfide. Other important Tues Isocyanates are 1,4-diisocyanatobutane, 1,2-diisocyanatododecane and Dimer fatty acid diisocyanate. Interest partially disguised Polyisocyanates, which form the formation of self-crosslinking polyurethanes enable z. B. dimeric tolylene diisocyanate, or with example partially phenols, tertiary butanol, phthalimide, caprolactam reacted polyisocyanates.

The aforementioned isocyanates can be used alone or as a mixture be set. The suitable multifunctionals preferably contain nelles isocyanates on average 2 to a maximum of 4 NCO groups. The men conditions on the polyol mixture and on the mixture of multifunctional iso cyanates are chosen so that a certain ratio of NCO reactive groups to NCO groups is present. So z. B. at the Production of the polyurethane prepolymers according to the prepolymer iono mer mixing process, the isocyanate component is always stoichiometric surplus.

To chain extenders with reactive hydrogen count atoms:

• - The usual saturated and unsaturated glycols, such as ethylene glycol or condensates of ethylene glycol, 1,3-butanediol, butane diol-1,4, butenediol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, hexanediol, bis-hydroxymethyl-cyclohexane, dioxyethoxy hydroquinone, terephthalic acid bis-glycol ester, succinic acid di-2-hydroxyethylamide, succinic acid di-N-methyl- (2-hydroxy ethyl) amide, 1,4-di (2-hydroxy-methyl-mercapto) -2,3,5,6-tetra  chlorobenzene, 2-methylene propanediol (1,3), 2-methyl propanediol (1.3);
• - Aliphatic, cycloaliphatic and aromatic diamines such as Ethylene diamine, hexamethylene diamine, 1,4-cyclohexylene diamine, pi perazin, N-methyl-propylenediamine, diaminodiphenyl sulfone, diami nodiphenyl ether, diaminodiphenyldimethylmethane, 2,4-diamino-6- phenyltriazine, isophoronediamine, dimer fatty acid diamine, hydrazine, Diaminodiphenylmethane or the isomers of phenylenediamine. Furthermore also carbohydrazides or hydrazides of dicarboxylic acids.
• - Amino alcohols such as ethanolamine, propanolamine, butanolamine, N-Me ethyl ethanolamine, N-methyl-isopropanolamine;
• - Aliphatic, cycloaliphatic, aromatic and heterocyclic Mono- and diaminocarboxylic acids such as glycine, 1- and 2-alanine, 6- Aminocaproic acid, 4-aminobutyric acid, the isomeric mono- and Diaminobenzoic acids, the isomeric mono- and diaminonaphthoic acid ren;
• - Water

It should be emphasized that not strictly between connections with reactive hydrogen atoms as a polyol component and so mentioned "chain extenders" can be distinguished because the transitions between the two classes of connections are fluid. Compounds that are not made up of multiple monomer units are, but have a relatively high molecular weight, such as. B. 3,3'-dibromo-4,4'-diaminodiphenylmethane, become the chain extender agents, but also pentaethylene glycol, although the latter, according to its composition, is actually a polyether diol is.  

Special chain extenders with at least one basic Nitrogen atoms are e.g. B. mono-, bis- or polyoxalkylated alipha tables, cycloaliphatic, aromatic or heterocyclic primary Amines, such as N-methyldiethanolamine, N-ethyl-diethanolamine, N-propyl diethanolamine, N-isopropyl-diethanolamine, N-butyl-diethanolamine, N-isobutyl-diethanolamine, N-oleyl-diethanolamine, N-stearyl-dietha nolamine, ethoxylated coconut fatty amine, N-allyl-diethanolamine, N-Me thyl-diisopropanolamine, N-ethyl-diisopropanolamine, N-propyl-diiso propanolamine, N-butyl-diisopropanolamine, N-cyclohexyl-diisopropanol amine, N, N-dioxethylaniline, N, N-dioxethyltoluidine, N, N-dioxethyl-1- aminopyridine, N, N'-dioxethyl-piperazine, dimethyl-bis-oxethylhydra zin, N, N'-bis (2-hydroxyethyl) -N, N'-diethyl-hexahydro-p-phenylenedi amine, N-12-hydroxyethyl-piperazine, polyalkoxylated amines such as oxy propylated methyl diethanolamine, also compounds such as N-Me thyl-N, N-bis-3-aminopropylamine, N- (3-aminopropyl) -N, N'-dimethylethy lendiamine, N- (3-aminopropyl) -N-methylethanolamine, N, N'-bis- (3-ami nopropyl) -N, N'-dimethylethylenediamine, N, N'-bis (3-aminopropyl) -pi perazin, N- (2-aminoethyl) piperazine, N, N'-bisoxyethyl-propylenedi amine, 2,6-diaminopyridine, diethanolamino-acetamide, diethanolamido propionamide, N, N-bis-oxyethyl-phenyl-thiosemicarbazide, N, N-bis-oxe thyl-methyl-semicarbazide, p, p′-bis-aminomethyl-dibenzylmethylamine, 2,6-diaminopyridine, 2-dimethylaminomethyl-2-methyl-propanediol-1,3.

Chain extenders with halogen atoms or R-SO ₂ O groups capable of quaternization are, for example, glycerol-1-chlorohydrin, glycerol monotosylate, pentaerythritol-bis-benzenesulfonate, glycerol-monomethanesulfonate, adducts of diethanolamine and chloromethylated aromatic isocyanates or aliphatic aromatic isocyanates such as N, N-bis-hydroxyethyl-N'-m-chloromethylphenylurea, N-hydroxyethyl-N'-chlorhexylurea, glycerol-mono-chloroethyl-ure than, bromoacetyl-dipropylenetriamine, chloroacetic acid diethanolamide. Particularly suitable chain extenders are short-chain diamines and / or dihydroxy compounds which are reactive toward isocyanates.

The so-called internal emulsifiers are known to those skilled in the art in aqueous solution known functional components capable of salt formation. For example, carboxylic acids, sulfonic acids or ammo are suitable nium compounds with 1 to 2 isocyanate-reactive groups pen. As such, dihydroxy or di can be used amino compounds that are an ionizable carboxylic acid, sulfonic acid or contain ammonium group. These connections can either can be used as such or they can be produced in situ will. In order to compounds containing ionizable carboxylic acid groups in The person skilled in the art can introduce the polyurethane into the polyols Add dihydroxycarboxylic acids that are not or only in the orderly measure of side reactions of the carboxyl groups with the iso cyanate groups are capable. A preferred dihydroxy carboxylic acid is, for example, dimethylol propionic acid.

In order to introduce sulfonic acid groups capable of salt formation, a diaminosulfonic acid can be added to the polyols. Examples are 2,4-diaminobenzenesulfonic acid but also the N- (omega-amino-al kan) -omega'-amino-alkanesulfonic acids as described in DE 20 35 732 are written.

If desired, the polyurethane prepolymers can at least par tially other reactive groups inserted instead of the NCO groups will. These can be, for example, alkoxysilane groups, mercapto groups and / or (meth) acrylic acid ester groups. Suitable Ver commitments to the introduction of these groups and corresponding procedures ren can z. B. DE-OS 36 29 237, DE-OS 36 01 189 and see DE-OS 32 45 563.  

The viscosity regulating properties of the ver Acetic esters can not only be used as viscosities kender effect in the manufacture of the polyurethane prepolymer, son also as long-term stability of the viscosity of the polyurethane disks express people. So z. B. polyurethane dispersions after the new hot dispersion method according to the German An notification with file number P 40 11 430.9 with the use of N-methyl-pyrrolidone were produced, depending on the recipe after 2 to 4 weeks thixotropic and thickened irreversibly after 3 to 6 weeks to puncture-resistant dispersions. With the 1: 1 replacement of N-methyl pyrrolidone by, for example, triazetine, are the polyurethane disks persions with otherwise the same recipe and the same procedure stable after 8 weeks and relatively low viscosity, so that they be can be used as intended. The same applies to some polyurethane dispersions made after the prepolymer ionomer Mixing processes with N-methyl-pyrrolidone were produced and after some time of storage thickened irreversibly. Here too leads a 1: 1 replacement by triazetin to a desired long-term sta the viscosity of the dispersion.

In addition, the acetic acid esters which can be used according to the invention are excellent as a plasticizer in aqueous polyurethane dispersions usable. The films formed from such dispersions tend the less brittleness, the higher the proportion of those mentioned Is acetic acid esters. The elasticity of the films can therefore be determined by the Content of the acetates mentioned are regulated. There is a significant advantage that no external plasticizers are supplied the must, but the one in the production of the polyurethane disperser Visions regulating component used simultaneously has the stated plasticizer properties when used.

The propanediols esterified with acetic acid and / or triol in as a surface treatment agent or as an adhesive  suitable polyurethane dispersions used. Those in the disper ions acetic acid esters used according to the invention can be the mentioned applications of the dispersions also favorably on the Affect film formation and can act as a coalescing agent. Surface treatment agents include coating means their application areas of paints and paints strokes range from hard surfaces to leather finishing compounds.

The invention is illustrated by the examples below tert.

Examples Definition and determination of the NCO value

The NCO value in a defined sample is a measure of the content on free, unreacted NCO groups in the isocyanate-containing Polymer solution or melt. The NCO value is generally in Percentage by weight - based on the analytical material available ben.

To determine the NCO value, between 0.5 and 1.0 g (accuracy down to 3 digits) of the NCO prepolymer is weighed into an Erlenmeyer flask and mixed with 50 ml toluene, 5 ml 0.5 normal toluene dibutylamine. Solution and 50 ml of isopropanol are added. After dissolving the NCO prepolymer, titrate against 0.5 normal aqueous hydrochloric acid in the presence of bromothymol blue (color change from blue to yellow). As a control, an NCO blank value (without NCO prepolymer sample) is determined. This results in the uncorrected NCO value:
% -NCO = blank value (ml) - consumption (ml) × 2.1 ′ / sample amount (g).

Production of the polyurethane dispersions after Prepolymer-ionomer mixing process Example 1

In a well-dried laboratory reactor made of glass with 3-stage noble steel MIG stirrers were at about 25 ° C 186.5 g glycerol × 7 EO × 81 PO (OHZ = 34), 47.7 g castor oil (OHZ = 158), 16.3 g 2,2-bis (hydroxy methyl) propanoic acid and 32.9 g of triacetin submitted and homogenized.

After the raw material has been released (water content <0.05% by weight if raw material drying must be carried out) 109.0 g of isophorone diisocyanate were added to the polyol mixture. After a short time After heating to 60 ° C., the reaction was carried out within 2.5 h to to a residual NCO content of 4.6% by weight (corrected value) leads.

30 minutes after the NCO value of 4.6% by weight was reached Add 13.1 g of N-methylmorpholine. After 15 minutes, an NCO Content of 4.2% by weight (corrected value) found. After another 15 Minutes, the addition of 569.0 g approx. 15 ° C cold demineralized water.

The fresh polyurethane, at around 38 ° C, was used to extend the chain dispersion heated to 60 ° C and at this temperature two more Stirred for hours, then cooled to 25 ° C and then bottled.

The white, stable, approx. 38.2% by weight aqueous polyurethane dispersion had a pH of 6.8 and a Brookfield viscosity of 50 mPa × s (at 25 ° C).  

Comparative Example 1

In a well-dried laboratory reactor made of glass with 3-stage noble steel MIG stirrers were at about 25 ° C 186.5 g glycerol × 7 EO × 81 PO (OHZ = 34), 47.7 g castor oil (OHZ = 158), 16.3 g 2,2-bis (hydroxyme thyl) propanoic acid and 32.9 g of N-methyl-pyrrolidone submitted and homo embarrassed.

After the raw material has been released (water content <0.05% by weight if raw material drying must be carried out) 109.0 g of isophorone diisocyanate were added to the polyol mixture. After a short time After heating to 60 ° C., the reaction was carried out within 2.5 h to to a residual NCO content of 4.6% by weight (corrected value) leads.

30 minutes after the NCO value of 4.6% by weight was reached Add 13.1 g of N-methylmorpholine. After 15 minutes, an NCO Content of 4.2% by weight (corrected value) found. After another 15 Minutes, the addition of 569.0 g approx. 15 ° C cold demineralized water.

The fresh polyurethane, at around 38 ° C, was used to extend the chain dispersion heated to 60 ° C and at this temperature two more Stirred for hours, then cooled to 25 ° C and then bottled.

The white, stable, approx. 38.2% by weight aqueous polyurethane dispersion had a pH of 7.1 and a Brookfield viscosity of 150 mPas (at 25 ° C).  

Example 2

In a well-dried 3-stage glass laboratory reactor Stainless steel MIG stirrers were made from 182.6 g polyester at approx. 25 ° C Adipic acid, isophthalic acid and diethylene glycol with an OH value of 59, 32.3 g soybean polyol (soybean oil polyepoxide ring-opened with methanol with the OHZ of 200), 30.0 g of 2,2-bis (hydroxymethyl) propanoic acid, 27.2 g N-methylmorpholine and 45.1 g of triacetin submitted and homogenized.

After release of raw materials (water content <0.05% by weight, if necessary the raw materials must be dried) 146.7 g of isophorone added diisocyanate to the raw material mixture. After rapid heating the reaction was brought to 80 ° C. in the course of 2.0 h until NCO content of 5.2 wt .-% (corrected value) carried out.

Subsequently, 528.7 g of approximately 60 ° C. became warm within 5 minutes demineralized water added to the dispersion preparation.

For chain extension, 3.3 g of glycerol × 7 EO × 81 PO (OHZ 34) added to the fresh, approx. 65 ° C warm polyurethane dispersion. To Stirring for 4 hours was cooled to 25 ° C and then bottled.

The white, stable, approx. 39.2% by weight aqueous polyurethane dispersion had a pH of 7.2 and a Brookfield viscosity of 13,200 mPa · s (at 20 ° C).  

Comparative Example 2

In a well-dried 3-stage glass laboratory reactor Stainless steel MIG stirrers were made from 182.6 g polyester at approx. 25 ° C Adipic acid, isophthalic acid and diethylene glycol with an OH value of 59, 32.3 g soybean polyol (soybean oil polyepoxide ring-opened with methanol with the OHZ of 200), 30.0 g of 2,2-bis (hydroxymethyl) propanoic acid 27.2 g N-methylmorpholine and 45.1 g of N-methyl-pyrrolidone submitted and homo embarrassed.

After release of raw materials (water content <0.05% by weight, if necessary the raw materials must be dried) 146.7 g of isophorone added diisocyanate to the raw material mixture. After rapid heating the reaction was brought to 80 ° C. in the course of 2.0 h until NCO content of 5.2 wt .-% (corrected value) carried out.

Subsequently, 528.7 g of approximately 60 ° C. became warm within 5 minutes demineralized water added to the dispersion preparation.

For chain extension, 3.3 g of glycerol × 7 EO × 81 PO (OHZ 34) added to the fresh, approx. 65 ° C warm polyurethane dispersion. To Stirring for 4 hours was cooled to 25 ° C and then bottled.

The white, stable, approx. 39.3% by weight aqueous polyurethane dispersion had a pH of 7.3 and a Brookfield viscosity of 1500 mPa · s (at 20 ° C).  

Example 3

In a well-dried 3-stage glass laboratory reactor Stainless steel MIG stirrers were made from 182.6 g polyester at approx. 25 ° C Adipic acid, isophthalic acid and diethylene glycol with an OH value of 59, 72.7 g soybean polyol (soybean oil poly opened with lead fatty acid epoxy with an OH value of 84.6), 30.0 g of 2,2-bis (hydroxymethyl) propane acid, 27.2 g of N-methylmorpholine and 45.1 g of triacetin and homogenized.

After release of raw materials (water content <0.05% by weight, if necessary the raw materials must be dried) 146.7 g of Isopho rondiisocyanate added to the raw material mixture. After a quick warm-up zen to 80 ° C, the reaction within 2.0 h to a Residual NCO content of 2.54 wt .-% (uncorrected value) carried out.

Then 592.0 g of about 15 ° C. became cold within 5 minutes demineralized water added for the preparation of the dispersion.

The fresh polyurethane, which was around 35 ° C warm, was used to extend the chain dispersion heated to 60 ° C and four hours at this temperature stirred, then cooled to 25 ° C and then bottled.

The white, stable, approx. 39.3% by weight aqueous polyurethane dispersion had a pH of 7.1 and a Brookfield viscosity of 300 mPa · s (at 20 ° C).  

Comparative Example 3

In a well-dried 3-stage glass laboratory reactor Stainless steel MIG stirrers were made from 182.6 g polyester at approx. 25 ° C Adipic acid, isophthalic acid and diethylene glycol with an OH value of 59, 72.7 g soybean polyol (soybean oil poly opened with lead fatty acid epoxy with an OH value of 84.6), 30.0 g of 2,2-bis (hydroxymethyl) propane acid, 27.2 g of N-methylmorpholine and 45.1 g of N-methylpyrrolidone placed and homogenized.

After release of raw materials (water content <0.05% by weight, if necessary the raw materials must be dried) 146.7 g of Isopho rondiisocyanate added to the raw material mixture. After a quick warm-up zen to 80 ° C, the reaction within 2.0 h to a Residual NCO content of 2.54 wt .-% (uncorrected value) carried out. Then 592.0 g of about 15 ° C. became cold within 5 minutes demineralized water added to the dispersion preparation.

The fresh polyurethane, which was around 35 ° C warm, was used to extend the chain dispersion heated to 60 ° C and four hours at this temperature stirred, then cooled to 25 ° C and then bottled.

The white, stable, approx. 39.5% by weight aqueous polyurethane dispersion had a pH of 7.2 and a Brookfield viscosity of 4500 mPa · s (at 20 ° C).

The above examples and comparative examples clearly show that triazetin is a suitable substitute for high-boiling solutions agents such as N-methyl-pyrrolidone in the manufacture of polyurethane dispersions after the prepolymer ionomer mixing process and this also applies if different polyol components are used the.  

Production of the polyurethane dispersions by the acetone process Example 4

In a well-dried 3-stage glass laboratory reactor Stainless steel MIG stirrers became 265.1 g polypropylene glycol at approx. 25 ° C (OHZ = 108), 0.27 g dibutyltin dilaurate and 87.0 g hexamethylene di submitted isocyanate.

After rapid heating to 70 ° C, the reaction within 5.0 h up to a residual NCO content of 6.4% by weight (corrected value) carried out.

After the NCO value of 6.5% by weight was reached, the addition of 17.8 g of 2,2-bis (hydroxymethyl) propanoic acid, 13.4 g of triethylamine and 30.0 g triacetin.

After a reaction time of 1.0 h at 70 ° C, an NCO content of Found 1.7% by weight (uncorrected value) and with the addition of 594.8 g of deionized water about 15 ° C cold started. The water- The addition was completed within 3 minutes.

The fresh polyurethane, which was around 35 ° C warm, was used to extend the chain dispersion heated to 50 ° C and at this temperature another Stirred for an hour, then cooled to 25 ° C and then bottled.

The white, stable, approx. 36.1% by weight aqueous polyurethane dispersion had a pH of 6.7 and a Brookfield viscosity of 190 mPas (at 25 ° C).  

Comparative Example 4

In a well-dried laboratory reactor made of glass with 3-stage noble Steel MIG stirrers were 265.1 g polypropylene glycol (OHZ = 108), 0.27 g dibutyltin dilaurate and 87.0 g hexamethylene diisocyanate submitted nat.

After rapid heating to 70 ° C, the reaction within 5.0 h up to a residual NCO content of 6.4% by weight (corrected value) carried out.

After the NCO value of 6.5% by weight was reached, the addition of 17.8 g of 2,2-bis (hydroxymethyl) propanoic acid, 13.4 g of triethylamine and 87.0 g acetone.

After a reaction time of 2.5 h at 67 ° C, an NCO content of 1.4% by weight (uncorrected value) was found and with the addition of 594.8 g of deionized water about 15 ° C cold started. The what water addition was completed within 3 minutes.

The fresh polyurethane, which was around 35 ° C warm, was used to extend the chain dispersion heated to 50 ° C and three more at this temperature Hours stirred.

Parallel to chain extension, the ver used acetone, mixed with water, distilled off.

After the end of distillation, 102.0 g of distillate were obtained, the fer termed polyurethane dispersion cooled to 25 ° C and then filled.

The white, stable, approx. 38.9% by weight aqueous polyurethane dispersion had a pH of 7.0 and a Brookfield viscosity of 850 mPas (at 20 ° C).  

Example 5

In a well-dried laboratory reactor made of glass with 3-stage noble Steel MIG stirrers were 239.3 g polytetrahydrofuran at approx. 25 ° C (OHZ = 55.8), 37.3 g of 2,2-bis (hydroxymethyl) propanoic acid, 117.19 g Isophorone diisocyanate and 20.0 g of triacetin submitted.

After rapid heating to 80 ° C, the reaction within 4.0 h  up to a residual NCO content of 2.8% by weight (uncorrected value) carried out.

After the NCO value had been reached, approx. 384.5 g were added. 15 ° C cold sodium hydroxide solution (5.6 g sodium hydroxide in 378.9 g completely salted water) started. The addition of the sodium hydroxide solution was within completed by 3 minutes.

Immediately after the sodium hydroxide solution had ended, 91.7 g of ammoni Acid solution (9.6 g 25.0% by weight ammonia in 82.1 g demineralized Water) for fresh polyurethane dispersion within 2 minutes given.

The fresh polyurethane, which was around 35 ° C warm, was used to extend the chain dispersion heated to 50 ° C and at this temperature two more Stirred for hours, then cooled to 25 ° C and then bottled. Before filling, the polyurethane dispersion was 20.0% by weight with 14.6 g aqueous sodium hydroxide solution adjusted to pH 6.8.

The white, stable, approx. 47.1% by weight aqueous polyurethane dispersion had a Brookfield viscosity of 730 mPas (at 25 ° C).  

Comparative Example 5

In a well-dried 3-stage glass laboratory reactor Stainless steel MIG stirrers were 239.3 g polytetrahydrofuran at about 25 ° C (OHZ = 55.8), 37.3 g of 2,2-bis (hydroxymethyl) propanoic acid, 117.19 g Isophorone diisocyanate and 43.0 g of acetone submitted.

After rapid heating to 67 ° C, the reaction was within 6.5 h up to a residual NCO content of 2.6% by weight (uncorrected value) carried out.

After the NCO value had been reached, approx. 15 ° C cold sodium hydroxide solution (5.6 g sodium hydroxide in 408.9 g completely salted water) started. The addition of the sodium hydroxide solution was within completed by 3 minutes.

Immediately after the sodium hydroxide solution had ended, 91.7 g of ammoni Acid solution (9.6 g 25.0% by weight ammonia in 82.1 g demineralized Water) for fresh polyurethane dispersion within 2 minutes given.

The fresh polyurethane, which was around 35 ° C warm, was used to extend the chain dispersion heated to 50 ° C and three more at this temperature Hours stirred.

Parallel to chain extension, the ver used acetone, mixed with water, distilled off.

After the end of distillation, 82.0 g of distillate were obtained, the finished Polyurethane dispersion cooled to 25 ° C and then bottled.

Before filling, the polyurethane dispersion was 20.0% by weight with 13.9 g aqueous sodium hydroxide solution adjusted to pH 6.8.

The white, stable, approx. 48.3% by weight aqueous polyurethane dispersion had a Brookfield viscosity of 2200 mPa · s (at 25 ° C).  

As is clear from the above examples and comparative examples triazetin is an excellent substitute for low-boiling solvents such as acetone in the so-called acetone Method. This also applies if different isocyanate components ten are used. Instead of that in the comparative examples Acetone used in the examples according to the invention only about half to a third of this amount of triazetin puts.  

Production of the polyurethane dispersions after Hot dispersion process Example 6

In a well-dried 3-stage glass laboratory reactor Stainless steel MIG stirrers were at about 25 ° C 186.5 g glycerol × 7 EO × 81 PO (OHZ = 34), 47.7 g castor oil (OHZ = 158), 16.3 g 2,2-bis (hydroxymethyl) propanoic acid, 13.1 g N-methylmorpholine and 32.9 g Triacetin submitted and homogenized.

After the raw material has been released (water content <0.05% by weight if a raw material drying must be carried out) were 99.1 g Isophorone diisocyanate added to the polyol mixture. Subsequently the reaction mixture was heated at a rate of 1 ° C per minute heated to the reaction temperature of 60 ° C. The following approx The reaction was 2.5 hours to a residual NCO content of 4.2 % By weight (corrected value).

15 minutes after reaching this NCO value took place within 10 minutes continuously adding 569.0 g of hot 60 ° C full desalinated water.

The fresh polyurethane, which was approx. 60 ° C warm, was used to extend the chain dispersion stirred at this temperature for two more hours finally cooled to 25 ° C and then bottled.

The white, storage-stable, approximately 38.2% by weight aqueous polyurethane dis persion had a pH of 6.8 and a Brookfield viscosity of 50 mPa × s (at 25 ° C).  

Comparative Example 6

In a well-dried 3-stage glass laboratory reactor Stainless steel MIG stirrers were at about 25 ° C 186.5 g glycerol × 7 EO × 81 PO (OHZ = 34), 47.7 g castor oil (OHZ = 158), 16.3 g 2,2-bis (hydroxymethyl) propanoic acid, 13.1 g N-methylmorpholine and 32.9 g N-methyl-pyrrolidone submitted and homogenized.

After the raw material has been released (water content <0.05% by weight if a raw material drying must be carried out) were 99.1 g Isophorone diisocyanate added to the polyol mixture. With an up heating rate of 1 ° C per minute, the reaction mixture on the Re action temperature of 60 ° C warmed. The following approx. 2.5 hours reaction to a residual NCO content of 4.2 wt .-% (corrected value).

15 minutes after reaching this NCO value took place within 10 minutes continuously adding 569.0 g of hot 60 ° C full desalinated water.

The fresh polyurethane, which was approx. 60 ° C warm, was used to extend the chain dispersion stirred at this temperature for two more hours finally cooled to 25 ° C and then bottled.

The white, about 38.2 wt .-% aqueous polyurethane dispersion had a pH of 6.9 and a Brookfield viscosity of 150 mPa · s (at 25 ° C).

This polyurethane dispersion thickened within about 2 weeks (approx. 60,000 mPa × s), but could be removed by shaking vigorously (Thixotropy) reduce its viscosity again (approx. 5000 mPa × s). After another 3 weeks, the polyurethane dispersion was insane Versibly thickened (puncture-proof).  

Example 6 and the related comparative example are from Recipe analogous to Example 1 and Comparative Example 1, were each not according to the prepolymer-ionomer mixing method, but according to the new hot dispersion method according to the German application the file number P 40 11 430.9. In contrast to the ver same example 6, in which the polyurethane dispersion after 3 weeks is irreversibly thickened in Example 6, in the N-methylmorpholine the polyurethane was replaced by the same amount of triazetin dispersion still low viscosity even after several weeks.  

Process changeover from the acetone process to the Prepolymer-ionomer mixing process Example 7

In a well-dried laboratory reactor made of glass with 3-stage noble Steel MIG stirrers were 265.1 g polypropylene glycol (OHZ = 108), 0.27 g dibutyltin dilaurate and 87.0 g hexamethylene diisocyanate submitted nat. After rapid heating to 70 ° C, the reaction within 5.0 h up to an NCO content of 6.4% by weight (corr value) carried out.

After the NCO value of 6.4% by weight had been reached, 17.8 g of 2,2-bis (hydroxymethyl) propanoic acid, 8.9 g of triethylamine and 30.0 g triacetin.

After a reaction time of 2.0 h at 70 ° C, an NCO content of Found 1.7% by weight (uncorrected value) and with the addition of 594.8 g of demineralized water about 15 ° C cold started. The water- The addition was completed within 3 minutes.

The fresh polyurethane, which was around 35 ° C warm, was used to extend the chain dispersion heated to 50 ° C and at this temperature another Stirred for an hour, then cooled to 25 ° C and then bottled. The white, about 36.4 wt .-% aqueous polyurethane dispersion had a pH of 6.7 and a Brookfield viscosity of 700 mPa · s (at 25 ° C).

When storing this polyurethane dispersion, it was found that they have a higher viscosity (approx. 2000 mPa × s) within 4-6 weeks assumed that, however, by shaking the ur previous value could be reduced (thixotropy). After total After 8-9 weeks the viscosity was still below 2500 mPa × s.  

Comparative Example 7a

In a well-dried laboratory reactor made of glass with 3-stage noble Steel MIG stirrers were 265.1 g polypropylene glycol (OHZ = 108), 0.27 g dibutyltin dilaurate and 87.0 g hexamethylene diisocyanate submitted nat.

After rapid heating to 70 ° C, the reaction within 5.0 h up to an NCO content of 6.4% by weight (corrected value) guided. After the NCO value of 6.4% by weight was reached, the Add 17.8 g of 2,2-bis (hydroxymethyl) propanoic acid, 8.9 g of triethyl amine and 30.0 g of N-methyl-pyrrolidone.

After a reaction time of 2.5 h at 70 ° C, an NCO content of 1.6% by weight (uncorrected value) was found and with the addition of 594.8 g of demineralized water about 15 ° C cold started. The what water addition was completed within 3 minutes.

The fresh polyurethane, which was around 35 ° C warm, was used to extend the chain dispersion heated to 50 ° C and at this temperature another Stirred for an hour, then cooled to 25 ° C and then bottled.

The white, about 37.8 wt .-% aqueous polyurethane dispersion had a pH of 6.9 and a Brookfield viscosity of 70 mPa × s (at 25 ° C).

When storing this polyurethane dispersion, it was found that they have a higher viscosity (approx. 10,000 mPa × s), which, however, by intensive shaking up the original value could be reduced (thixotropy). To however, this dispersion was irreversibly ver for a total of 4-5 weeks thick (puncture-proof).  

Comparative Example 7b

In a well-dried laboratory reactor made of glass with 3-stage noble Steel MIG stirrers were 265.1 g polypropylene glycol (OHZ = 108), 0.27 g dibutyltin dilaurate and 87.0 g hexamethylene diisocyanate submitted nat.

After rapid heating to 70 ° C, the reaction within 5.0 h up to a residual NCO content of 6.4% by weight (corrected value) carried out.

After the NCO value of 6.4% by weight had been reached, 17.8 g of 2,2-bis (hydroxymethyl) propanoic acid, 13.4 g of triethylamine and 80.0 g acetone.

After a reaction time of 2.5 h at 65 ° C, an NCO content of 1.5% by weight (uncorrected value) found. Parallel to the NCO / OH-Um this was used to dissolve the 2,2-bis (hydroxymethyl) propanoic acid / - Triethylamine salt required acetone continuously by application distilled off from vacuum.

After reaching the specified NCO value and after distilling About 90% of the acetone used was 594.8 g about 15 ° C cold demineralized water metered to the polymer melt. The water addition was completed within 3 minutes.

The fresh polyurethane, which was around 35 ° C warm, was used to extend the chain dispersion heated to 50 ° C and at this temperature another Stirred for an hour, then cooled to 25 ° C and then bottled.

The white, storage-stable, approx. 37.3% by weight aqueous polyurethane dis persion had a pH of 7.1 and a Brookfield viscosity of 40 mPa × s (at 25 ° C).  

The one prepared by the acetone method in Comparative Example 7b Polyurethane dispersion has very good application technology properties and is also stable in terms of viscosity. The Manufacturing process, however, involves the undesirable step the distillation. After the prepolymer-ionomer mixing process with N-methyl-pyrrolidone, as shown in Comparative Example 7a, who although also polyurethane dispersions with good application technical properties achieved, however, are subject to the be undesirable irreversible Verdic kung. The polyurethane dispersion desired as a product was therefore So far only in the storage-stable variant using the acetone process producible. On the basis of example 7, it is demonstrated that a 1: 1 Replacement of triazetin instead of N-methyl-pyrrolidone the prepoly mer ionomer mixing process leads to products that have the desired have application properties and at longer La only a relatively slight increase in viscosity to draw.

Claims (7)

1. Use of propanediols esterified with acetic acid and / or -triol as a viscosity-regulating, non-reactive component in the production of aqueous storage-stable polyurethane disks persions according to methods known per se. 2. Embodiment according to claim 1, characterized in that at the processes known per se, in particular in the acetone, Melt emulsifying or prepolymer-ionomer mixing processes using Acetic acid esterified propanediols and / or triol instead of known solvents can be used. 3. Embodiment according to one of the preceding claims, characterized characterized in that in the known methods, esp especially in the prepolymer-ionomer mixing process, instead of the be knew about the same amount of high-boiling solvent Use propane diols and / or triol esterified with acetic acid det. 4. Embodiment according to one of the preceding claims, characterized characterized in that in the known methods, esp especially in the acetone process, instead of the known low solvents about half to a third of their amount on propane diols and / or triol esterified with acetic acid is applied. 5. Use of propanediols esterified with acetic acid and / or -triol as a plasticizer and / or coalescing agent in aqueous Polyurethane dispersions.   6. Embodiment according to one of the preceding claims, characterized characterized in that the propanediols esterified with acetic acid and / or triol in as a surface treatment agent or as Suitable polyurethane dispersions can be used. 7. Embodiment according to one of the preceding claims, characterized characterized in that glycerol triacetate is used.