DE1942927B2 - PROCESS FOR THE PREPARATION OF Aqueous ANIONIC POLYURETHANE DIPERSIONS - Google Patents

Description

H, N - ZX - Z '- NH ₂

X =
or

-CH-

-N-

(at m = 0)

(at m = 1) SO ₃ Me
in which Z, Z 'are identical or different and are alkylene radicals,

X =

denotes, where Z, Z ', X together can represent a cycloalkylene radical, Y an alkylene, hydroxyalkylene or hydroxyetheralkylene radical, 40 Me = Li, Na, K, Rb, Cs, NH ₄ , NHR ₃ , NH ₂ R ₂ , ^{or the like} NH ₃ R 'and R' = alkyl (C ₁ -C ₄ ) can be used.

-CH-

—N—

(at m = 0)

(at m - 1)

The production of aqueous, emulsifier-free polyurethane dispersions by dispersing Polyurethane compositions containing salt groups in water are known. These contained in the polyurethanes and salt groups firmly bonded with them exert an emulsifier effect and allow the production of dispersions without the need for emulsifiers or other emulsifying aids during dispersion must be added.

Various processes have become known for introducing salt groups into polyurethanes. It is thus possible to introduce the salt groups into the polyurethane in the form of chain extenders containing salt groups and having reactive hydrogen atoms by reacting these chain extenders containing salt groups with pre-adducts containing isocyanate groups. The salts of diaminosulfonic acids which are used as alkali metal or ammonium salts have proven particularly suitable as chain lengthening agents containing salt groups. denote, where Z, Z ', X together can represent a cycloalkylene radical and Y an alkylene, hydroxyalkylene or hydroxyetheralkylene radical, Me = Li, Na, K, Rb, Cs, NH ₄ , NHR ₃ , NH ₂ R ₂ , NH ₃ R 'and R' = alkyl (C ₁ -C ₄ ).

The dispersions prepared with the salts of these technically easily accessible diaminosulfonic acids allow the production of lightfast and colorless films, threads, coatings, impregnations, Bondings and intermediate layers.

The invention accordingly provides a process for the production of aqueous, emulsifier-free, anionic polyurethane dispersions obtained by the isocyanate polyaddition process Polyurethanes with a content of 0.05% to 5% by weight of SOf groups (based on the dry Polyurethane) by reacting higher molecular weight polyhydroxy compounds with a Molecular weight of 300-20000, polyisocyanates, optionally with chain extenders with reactive hydrogen atoms to be used and alkali or ammonium salts of diaminosulfonic acids, and conversion into per se known manner in aqueous dispersions, the da-

is characterized in that as salts of diarcinosulfonic acids those of the general formula

H ₂ NZXZ-NH ₂

SO ₃ Me

in which Z, Z ', X, Y, Me have the meaning already mentioned, can be used.

The alkali or ammonium salts of the diaminosuric acid to be used according to the invention are e.g. by adding alkali hydrogen sulfites such as sodium bisulfite, ammonium bisulfite or alkali pyrosulfites, such as potassium pyrosulfite, unsaturated dinitriles, dinitrile epoxides or dinitrile-1-chloro-2-hydroxy-alkanes and subsequent hydrogenation of the dinitrilsulfonic acid salts obtained.

Dinitriles suitable for the process are, for example: 1,4 - dicyanobutene- (2) -, 1,4 - dicyanobutene- (l) -, 4-Cyclohexene-1,2-dinitrile, also AlIyI-bis- (2-cyano-ethyl) -amine, allyl- (2-hydroxypropyl) -ether-bis- (2-cyanoethyl) -amine, 1 -Chlor-2-hydroxypropyl - bis - (2 - cyanoethyl) amine and 1,2-epoxypropyl bis (2-cyanoethyl) amine of the structural formulas below

also dinitriles of the formula I or II

NC (CH ₂ ) ₂ -N- (CH ₂ J ₂ -CN CH ₂
CH

Il

CH ₂

NC (CH ₂ ) ₂ -N- (CH ₂ J ₂ -CN

CH-OH

CH ₂
0-CH ₂ -CH = CH ₂

NC (CH ₂ J ₂ - N- (CH ₂ J ₂ -CN CH-OH NC- (CH ₂ J ₂ -N- (CH ₂ J ₂ -CN CH ₂ CH-R O

CH ₂ CH-OH

CH ₂ -Cl (IJ

NC- (CH ₂ J ₂ -N- (CH ₂ J ₂ -CN CH ₂ CH-R O CH,

CH \

CH ₂ (IIJ

in which R = H, alkyl, (C ₁ -C ₄ ), phenyl which is obtained by adding 2 mol of acrylonitrile to amino alcohols of the formula

40 H ₂ N

CH-OH R

and subsequent reaction with epichlorohydrin can be prepared.

Examples of suitable diamino-sulfonic acids or salts are the following compounds:

50 1,6-hexanediaminosulfonic acid- (3) H ₂ N- (CH ₂ J ₂ -CH- (CH ₂ J ₃ -NH ₂ SO ₃ Na

NC (CH ₂ J ₂ -N- (CH ₂ ) ₂ -CN CH ₂

CH
\

O
CH ₂

60 N - (Propyl - sulfonic acid - (3) - N ₁ N - [bis - (3 - aminoproepyl)] - amine

H ₂ N- (CH ₂ J ₃ -N- (CH ₂ J ₃ -NH ₂ (CH ₂ J ₂ CH ₂ SO ₃ H

N- [Propyl-sulfonic acid- (3H2-hydroxypropyl) -ether] -N, N- [bis- (3-aminopropyl)] - amine

H ₂ N- (CH ₂ ),

N-CH ₂ -Ch-CH ₂ -O-CH ₂ -CH ₂ -CH ₂ -SO ₃ H

H ₂ N- (CH ₂ ) ₃ OH

N-ß-Hydroxy-propyl-S-sulfoiisäureJ-KN-Cbis-ß-amino-propyl-amine

H ₂ N- (CH ₂ );

N-CH ₂ -CH-CH ₂ -SO ₃ H H ₂ N- (CH ₂ ) ₃ OH

; i <[- (2-Hydroxy-propyl-3- ^t ', sulfonic acid ethyl ether) -N, N- [bis- (3-aminopropyl)] - amine

H ₂ N- (CH ₂ K

N-CH ₂ -CH ₂ -O-CH ₂ -CH-Ch ₇ -SO ₃ H

/ ί

H ₂ N- (CH ₂ J ₃ OH

As starting components for the preparation of the dispersions according to the invention, for. B. the in the French patent 14 16463 and in the Belgian patent 6 73 432 listed higher molecular weight Polyhydroxy compounds with a molecular weight of 300-20,000. Polyisocyanates and chain extenders having reactive hydrogen atoms can be used.

Substantially linear compounds are included as higher molecular weight polyhydroxy compounds a molecular weight of about 300-20,000, preferably 600-4000, in question. Preference is given to polyesters containing hydroxyl groups and polyacetals. Polylactones. Polycarbonates, polyethers and polyester amides. The hydroxyl number of these compounds is usually about 10-100, preferably 50-70. As a chain extender with reactive Hydrogen atoms may include glycols, diamines, amino alcohols, and water Question. These compounds can optionally be used together with the higher molecular weight polyhydroxy compounds can be used, these low molecular weight compounds usually having molecular weights to about 300. But it is also possible in the absence of this low molecular weight Connections to work.

To vary the water resistance, the grip, the surface and the gloss properties of the Process products obtained impregnations. Strokes. Coatings and bonds it is advantageous to use higher molecular weight polyhydroxy compounds, as well as carbon-functional polysiloxanes with reactive hydroxyl groups with a Molecular weight from about 300-20,000, preferably 600-4000, to be used proportionally if necessary.

Such carbon-functional polysiloxanes and their production are for example in the French Patent 12 91937, in the German Auslegeschrift 11 14 632 and in German patents 12 48 287 and 15 70 576.

All aromatic and aliphatic diisocyanates are suitable as polyisocyanates, and they are preferred for the production of polyurethane compositions that do not discolour in the presence of light, especially the aliphatic or cycloaliphatic diisocyanates, such as butane-1,4-diisocyanate, 1,6-hexane diisocyanate, isophorone diisocyanate. Diisocyanatocarboxylic acid esters, such as ethyl 2,6-diisocyanatohexanoate, Trimethyl hexane diisocyanate. Xylylene diisocyanate, dicyclohexylmethane diisocyanate. Cyclohexane diisocyanate- (1,4), 1-methyl-cyclohexane-2,4- and -2,6-diisocyanate, and mixtures thereof. As aromatic diisocyanates are 1,3- and 1,4-phenylene diisocyanate, Called 2,4- and 2,6-tolylene diisocyanate.

In the preparation of the aqueous, emulsifier-free polyurethane dispersion according to the invention, it is expedient initially from the higher molecular weight polyhydroxy compound with a molecular weight of 300-20,000, preferably 600-4000, the polyisocyanates and the low molecular weight chain extenders which may also be used reactive hydrogen atoms prepared a pre-adduct containing isocyanate groups and in organic solution with that optionally present in solution to be used according to the invention Reacted salt of diaminosulfonic acid. The resulting, predominantly linear or branched, High molecular weight, anionic polyurethanes are added to the aqueous phase by adding water transferred and the organic solvent removed at the same time or subsequently completely or partially.

In principle it is also possible to proceed in such a way that the salt of diaminosulfonic acid is in aqueous Submitted solution and stirred in the pre-adduct containing isocyanate groups. It is also possible, all the water together with the salt of the diaminosulfonic acid containing the isocyanate groups Add pre-adduct.

As a solvent for the isocyanate group-containing Pre-adduct are preferably low-boiling organic solvents such as acetone, tetrahydrofuran, Methyl ethyl ketone and tertiary butanol used, although it is also quite possible with Use water-immiscible, low-boiling solvents such as benzene and methylene chloride.

Low-boiling alcohols such as metha-

nol and ethanol or water, optionally with the addition of other organic solvents, can be used. The pre-adduct containing isocyanate groups is prepared in generally useful at higher temperatures, whereby selected when using aliphatic diisocyanates temperatures between 100 and 13O ⁰ C. When aromatic diisocyanates generally suffice 60-100 ⁰ C. In the production of the preadduct, the amount of polyisocyanate is that all reactive with isocyanate groups react preferentially selected; in addition, a small excess of diisocyanates can be used. In general, the ratio of the isocyanate groups to the isocyanate-reactive groups is not greater than 1.3 1.5.

After the melt has cooled, the pre-adduct is taken up with the organic solvent and at 20-80 ° C. with the diaminosulfonic acid salt which may be present in solution offset The pre-adduct can, if too high viscosities occur during its production, also below Addition of solvents such as acetone. Tetrahydrofuran or methyl ethyl ketone, optionally under Pressure, to be produced.

The proportion of sulfonate groups —SO ₃ in the poly urethane is 0.05 to 8, preferably 0.5 4 percent by weight. The amounts of diaminosulfonic acid to be used should be selected accordingly. The sulfonate group content can thus be varied within wide limits. However, it should not fall below the lower limit mentioned, since otherwise the stability of the dispersions which are built up according to the invention without the use of auxiliaries such as emulsifiers, dispersants or swelling agents is impaired.

For conversion into the aqueous phase, the organic solvents by distillation or blowing out, e.g. B. at temperatures between 30 and 80 C. removed. The solvent is preferably removed in vacuo.

In this way, aqueous dispersions can be obtained in the form of low to high viscosity, non-sedimenting ones Lactices with an average particle size between 0.02 and 1.0 μ, preferably 0.05-0.2 μ, and one Solids content, usually from 20-60%, is preserved.

The dispersions according to the invention are stable, can be stored and shipped and can be used at any later time Time to be processed form-giving.

The dispersions generally dry immediately at room temperature or higher temperatures to form stable foils and coatings. Higher temperatures are preferred. The dispersions according to the invention can still be crosslinked, for. B. by polyfunctional, crosslinking substances, such as formaldehyde or formaldehyde-releasing or with formaldehyde reacting substances, such as hexamethylolmelamine or carbamide resins, also blocked by phenolic resins Polyisocyanates or polyepoxides. This is then done with cross-linked coatings. Impregnations and Receive adhesive layers.

Dispersions according to the invention are mainly used as coatings and impregnations for different substrates like paper. Cardboard. Textiles. Leather, fleece. Wood and metals, as adhesion promoters. Binders and glue and for making threads. Films and transparencies used. The ones from the Molded articles, coatings and impregnations obtained from dispersions have good properties Water and oil resistance and prove to be above all against those according to the Belgian patent 6 73 432 using e.g. B. 2,4-diamino-benzenesulfonic acid manufactured products desirably to be colorless and lightfast.

The dispersions can with anionic polymer or copolymer dispersions, for example of vinyl chloride, ethylene, styrene, butadiene. Vinylidene chloride, vinyl acetate, acrylate and acrylonitrile be blended. Fillers can also be used. Plasticizers. Pigments. Carbon black, aluminum powder. Bronze powder. Volume-. Asbestos and tar disper

■ 5 sions are incorporated into the dispersions.

Preparation of the diaminosulfonic acids to be used according to the invention

A. Sodium 1,6-diaminohexane-3-sulfonate

The compound was according to the Dutch patent 6: 5 13 521 from butene-2-dinitril- (1,4) produced by the addition of sodium bisulfite and subsequent catalytic hydrogenation.

B. Sodium 3- [di- (3-aminopropyl-amino-2-hydroxy-propoxy] -propanesulfonate

171 g of allyl glycidyl ether are mixed with 123 g of iminodipropionitrile Heated to 95 C for 16 hours.

After distilling off the excess allyl glycidyl ether at a pressure of 1 Torr remains in quantitative yield [di- (2-cyanoethyl- (l) -amino-2-hydroxy-propyI] allyl ether (I) as a light yellow oil.

238 g of the unsaturated compound I are heated with 230 g of 40% strength sodium hydrogen sulfite solution to 50 ° C. for 8 hours and to 80 ° C. for a further 8 hours. The excess of I is extracted with benzene (2 × 250 ml) and d ^; e aqueous solution evaporated to dryness in a rotary evaporator in vacuo. 88% of the theory of sodium 3- [di- (2-cyanoethyl- (I) -amino-2-hydroxy-propoxy] -propanesulfonate (II)) are obtained as an ointment-like mass.

260 g of II are dissolved in 1000 ml of water and, after addition of 250 ml of liquid ammonia, hydrogenated in the presence of 50 g of Raney cobalt at 150 at and 90.degree. The hydrogenation is complete after 4 hours. After filtering off the catalyst, the aqueous solution is evaporated to dryness in a rotary evaporator under vacuum. It is sodium 3- [di- (3-aminop opyl- ^r (l) amino-2-hydroxy-propoxy] - propanesulfonate obtained as a highly viscous mass in quantitative yield.

H ₂ N- (CH ₂ ),

H ₂ N- (CH ₂

N-CH ₂ -CH-CH ₂ -O- (CH ₂ J ₃ -SO ₃ Na

OH

Examples example 1

250 g of adipic acid-ethylene glycol polyester (OH number 56) are dewatered at 120'C for 30 minutes and then reacted 2 hours 38 g of 1,6-hexane at 120 C ^c. This pre-adduct containing isocyanate groups is cooled to 55 ⁰ C and added with 650 ml acetone. To this ace-

609 584/453

tonic pre-adduct solution becomes a solution of 13.6 g of sodium 1,6-diaminohexane-3-sulfonate with rapid stirring (prepared according to A) added to 60 ml of water. Then 380 ml of water stirred in. The batch is then stirred until the streaks that initially appear have disappeared and the approach has become homogeneous. The acetone is distilled off at 55 ° C. in a water jet vacuum. The dispersion obtained has a solids content of 40.5% with a residual acetone content of 0.4% and dries at room temperature to form clear, colorless films with good elasticity and tensile strength on.

Example 2

425 g of adipic acid - 1,6 - hexanediol - neopentyl glycol polyester (Molar ratio 30:22:12; OH number 67) are dehydrated at 120 C for 30 minutes and then 2 hours with 68 g of 1,6-hexane diisocyanate implemented at 120 C. The pre-adduct containing isocyanate groups is cooled and mixed with 1500 ml of acetone added. 43.6 sodium 3- [di- (3-aminopropyl- (1) -amino - 2 - hydroxy - propoxy] - propanesulfonate (prepared according to B) in 120 ml of water. To Briefly stirring, 850 ml of water are added and the acetone is stripped off in vacuo. the The resulting dispersion has a solids content of 33.4% and dries with it to give clear, colorless films high tensile strength.

Example 3

25Og adipic acid ethylene glycol polyester (OH number 56) are dehydrated at 120 ° C. for 30 minutes and then with 41 g of methylcyclohexane diisocyanate isomer mixture (Isomization ratio of 2,4-diisocyanate: 2,6-diisocyanate 80:20) 2 hours at 120 C implemented. The prepolymer melt is cooled to 55 ° C. and taken up in 700 ml of acetone. A solution of 11.4 g of sodium 1,6-di is added to the acetone solution with rapid stirring aminohexane-3-sulfonate (prepared according to A) was added in 60 m of water. Then 380 ml of water stirred in and the acetone was distilled off at 55 ° C. in a water jet vacuum. The dispersion obtained with a solids content of 41.8% dries to form smooth and firm coatings.

_{| 0} example 4

The procedure is as in Example 3, except that 250 g of polypropylene glycol ether are used instead of the polyester (OH number 56) is used, and the prepolymer reaction is carried out at 130 ° C. instead of 120 ° C. A stable dispersion with a solids content of 39% is obtained when it dries up provides a soft, slightly sticky film

Example 5

314.8 g of the hydroxyl-containing, carbon-functional polysiloxane of the average formula

HOCH ₂ -Si (CH ₃ J ₂ -O- [Si (CH ₃ I ₂ O] ₁₂ -I

Ls _{i (CH} , _{) 2} _ _CH2 oH

with a content of 2.7% OH are after dehydration at 120 C at 90 C with 79 g of 1,6-hexane diisocyanate added and reacted at 100 ° C. for 2 hours. After cooling to 50 ° C the liquid reaction mass is taken up with 1000 ml of acetone and with a solution of 36.3 g Sodium 3 - [di - (3 - aminopropyl - (I) - amino - 2 - hydroxy - propoxy] - propanesulfonate (manufactured by

measure B) added to 160 ml of water. After stirring for a short time, 600 ml of water are stirred in and the acetone stripped off in vacuo. The dispersion obtained with a solids content of 40.5% dries to a waxy film.

Claims (1)

Patents claim: Process for the production of aqueous, emulsifier-free, anionic polyurethane dispersions by the isocyanate polyaddition process obtained polyurethanes with a content of 0.05-8 percent by weight of SOf groups (based on the dry polyurethane) by reacting higher molecular weight polyhydroxy compounds with a molecular weight of 300-20,000, polyisocyanates, optionally chain extenders to be used with reactive hydrogen atoms and alkali or ammonium salts of diaminosulfonic acids, and conversion to an known manner in aqueous dispersions, characterized in that as salts of diaminosulfonic acids those of the general formula NH ₂ -ZXZ ^- -NH ₂ (V) _1n
SO ₃ Me in which Z, Z 'are identical or different and are alkylene radicals and Suitable diaminosulfonic acids are, for example, those known from dye chemistry Compounds such as 2,4-diaminobenzenesulfonic acid and others. A process for the production of polyurethane dispersions on this basis is in the Belgian Patent 6 73 432 described. These aromatic diaminosulfonic acids, which are readily available in themselves, are mostly technical products, which usually have only moderate solubility in the solvents commonly used and especially the polyurethanes made from them are highly photosensitive and strong Give a tendency to yellowing. Polyurethane dispersions made from them discolor in light and provide non-light-resistant coatings, coatings and foils. For these reasons, there was the problem of easily reproducible and lightfast polyurethane dispersions from diaminosulfonic acids, which are economically viable, technically accessible and in high purity are physiologically flawless. It has now been found that easily reproducible and lightfast, emulsifier-free polyurethane dispersions Can be prepared by using the readily available anionic chain extenders Salts of diaminosulfonic acids of the general formula can be used