DE1942927A1 - Process for the production of anionic polyurethane dispersions - Google Patents

Description

FARBENFABRIKEN BAYER AG

LEVERKUSEN-Biyerwerk Wr / Tr patent department

2 AUG. 1969

Process for the preparation of anionic polyurethane dispersions

The production of aqueous, emulsifier-free polyurethane dispersions by dispersing polyurethane compositions containing salt groups in water is known. This in the Polyurethanes containing and firmly connected salt groups exert an emulsifier effect and allow Production of dispersions without emulsifiers or other emulsifying aids being added during dispersion have to.

There are various ways of introducing salt groups into polyurethanes Procedure became known. It is thus possible to contain the salt groups in the polyurethane in the form of salt groups Introduce chain extenders with reactive hydrogen atoms by containing these salt groups Chain extenders are reacted with pre-adducts containing isocyanate groups. Have yourself particularly as chain extenders containing salt groups the salts of. Diaminosulfonic acids proven to be suitable, which are used as alkali or ammonium salts »

MA AM®

Suitable diaminosulfonic acids are, for example, the compounds known from dye chemistry, such as 2,4- * diaminobenzenesulfonic acid, among others.

These aromatic diaminosulfonic acids, which are readily available per se, are mostly technical products, which are generally only moderate in the solvents usually used Solubility, and especially the polyurethanes made from them, have a high sensitivity to light and are strong Give a tendency to yellowing. Polyurethane dispersions made from them discolour when exposed to light and provide light ·? fake coverings, coatings and foils.

For these reasons there was the problem of being easily reproducible and lightfast polyurethane dispersions made from diaminosulfonic acids, which are economically viable, technically in high purity are accessible and physiologically sound.

It has now been found that easily reproducible and lightfast> emulsifier-free polyurethane dispersions ^ can be prepared by using the easily accessible salts of diaminosulfonic acids of the general form as anionic chain extenders. be used,

H ₂ NZX-Z'-NH ₂ m

in which Z, Z 'are identical or different and are alkylene radicals, and X = -CH- (m = 0) or

N (α = 1) mean * where

Z, Z ', X together can represent a cycloalkylene radical and Y is an alkylene-, hydroxyalkylene- or hyiroxyether-

alkylene radical and Le A 12 440 - 2. * '

1 0 9 8 1 0/2 1 0 1

Me = Li, Na, K, Rb, Cs, NH ₄ , NHR '_3> NH ₂ R' ₂ , NH ₃ R ¹ 1942927

R '= alkyl (C ₁ -C ₄ ) "mean.

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

The present invention accordingly provides a process for preparing aqueous / emulsifier, anionic polyurethane dispersions% of by the isocyanate polyaddition process resulting polyurethanes having a content of 0.05-8 wt. Of SO ₃ ^e groups (based on the dry Polyurethane) by reacting higher molecular weight polyhydroxy compounds with a molecular weight of 300-20,000, polyisocyanates, optionally with chain extenders to be used with reactive hydrogen atoms and alkali or ammonium salts of diaminosulfonic acids and conversion in a manner known per se into aqueous dispersions, characterized in that as salts of diaminosulfonic acids, those of the general formula

Z ¹ , X, Y , Me H ₂ N-Z-X-Z '-NH will. SO ₃ Me in the Z, thieves riding used

The alkali or ammonium salts of the diaminosulphonic acids to be used according to the invention are produced, for example, by the addition of alkali hydrogen sulphites, such as sodium bisulphite, ammonium bisulphite or Alkali pyrosulfites, such as potassium pyrosulfite, to unsaturated ones

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dinitriles, dinitrile epoxides or dinitrile-1-chloro-2-hydroxy-alkanes and subsequent hydrogenation of the dinitrilsulfonic acids Salts won.

Dinitriles suitable for the process are, for example: l, J | -Dieyant> uten- (2), 1,4-dicyanobutene- (1), 4-cyclohexene-1,2-dinitrile, allyl-bis- (2-cyano- ethyl) amine, allyl (2-hydroxypropyl) ether bis (2-cyanoethyl) -amine, l-chloro-2-hydroxypropyl-bis- (2-cyanoethyl) -amine, l-2 _J-bis Epoxipropyl - (2-cyano - ethyl) amine

NC (GH ₂ ) _a -N- (CH ₂ ) ₂ -CN NC (CH ₂ ) ₂ -N- (CH ₂ ) ₂ -CN CI

5H ₂ -. CH ₂

3H "CH-OH

CH ₂ CH ₂

0-CH ₂ -CH = CH ₂

NC (CH ₂ ) s N- (CH ₂ ) ₂ -CN NC ^ CH ₂ ) ₂ -N- (CH ₂ ) ₂ -CN CH ₂ CH ₂

CH-OH CHn.

CH ₂ -Cl.

Furthermore, dinitriles of the formula I or II

NC- _(CH2) SN (CHs) ₂ -CN NC- (CH _{2) 2} -N- (CH _{2) 2} -CN

CH ₂ CH ₂

CH-R CH-R

ι. I.

0 0

I I

CH ₂ CH ₂

CH-OH CH ^

I I

CH ₂ -Cl CH ₂ /

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

, CH ₂ ^ and subsequent reaction with Epichiorhydrin her-HoIi XJH-OH

can be asked.

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

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

SO ₃ Na

N- (3-propyl-sulfonic acid) rtN, N- / bis- (3-aminopropyl27-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- / 5-propyl-sulfonic acid- (2-hydroxypropyl) -ether7-N, N- / ice- (3-aminopropyl) 7-amine

H ₂ N- (CH ₂ J _9x

N-CH ₂ -CH-Ch ₂ -O-CH ₂ -CH ₂ -CH ₂ -SO ₃ H H ₂ N- (CH ₂ J ₃ '^

N- (2-Hydroxypropyl-3-sulfonic acid J-N, N- / Sis- (3-aminopropyl) 7-amine

H ₂ N- (CH ₂ J ₃ >.

N-CH ₂ -CH-CH ₂ -SO ₃ H H ₂ N- (CH ₂ J ₃ "^

N- (2-Hydroxypropyl-3-sulfonic acid ethyl ether) -N, N- / ~ bis- (3-aminopropyl27-aniiri ^

H ₂ N- (CH ₂ J ₃ ^

N-CH ₂ -CH ₂ -O-CH ₂ -CH-CHg-SO ₃ H

OH Ie A 12 440 - 5 -

10 9810/2101

As starting components for the production of the dispersions according to the invention, for example, those in French patent specification 1 416 463 and in Belgian patent specification 673 listed higher molecular weight polyhydroxyl compounds with a molecular weight of 300-20000, polyisocyanates and Chain extenders with reactive hydrogen atoms can be used.

The higher molecular weight polyhydroxyl compounds are essentially linear compounds with a molecular weight from about 300-20,000, preferably 600-4000, in question. Preferred are polyesters containing hydroxyl groups, polyacetals, polylactones, polycarbonates, polyethers and polyester amides. The hydroxyl number of these compounds is usually about 10-100, preferably 50-70. Chain extenders with reactive hydrogen atoms may be used Glycols, diamines, amino alcohols and water in question. These compounds can optionally be used together be used with the higher molecular weight polyhydroxyl compounds, these low molecular weight compounds in the Usually have molecular weights up to about 300. But it is also possible to work in the absence of these low molecular weight compounds.

To vary the water resistance, the grip, the surface and the gloss properties of the impregnations and coatings obtained from the process products, Coatings and adhesives, it is often advantageous higher molecular weight polyhydroxyl compounds with a molecular weight of 300-20,000, optionally carbon-functional Polysiloxanes with reactive hydroxyl groups with a molecular weight of about 300-20,000, preferably 600-4000, to be used proportionally if necessary.

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Such carbon-functional polysiloxanes and their production are for example in the French patent specification 1 291 937, in the German Auslegeschrift 1 114 632 and in the German patent applications F 46 173 IVd / 39c and F 47 968 IVc / 39b.

All aromatic and aliphatic diisocyanates are suitable as polyisocyanates; Polyurethane compositions that do not discolour in the light, especially the aliphatic or cycloaliphatic diisocyanates, such as butane / ^ diisocyanate ^ ljö-hexane diisocyanate, Isophorone diisocyanate, diisocyanatocarboxylic acid esters such as ethyl 2,6-diisoeyanato-hexanoate, Trimethyl hexane diisocyanate, xylylene diisocyanate, Dicyclohexylmethane diisocyanate, cyclohexane diisocyanate (1,4), l-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 production of the. aqueous, emulsifier-free polyurethane dispersions According to the invention, it is expedient to first select the higher molecular weight polyhydroxyl compound with a molecular weight from 300-20,000, preferably 600-4000, the polyisocyanates and the low molecular weight ones which may also be used Chain extenders with reactive hydrogen atoms produced a pre-adduct containing isocyanate groups and in organic solution with the salt which is optionally present in solution and to be used according to the invention Diaminosulfonic acid implemented. The emerging, mostly linear or branched, high molecular weight, anionic polyurethanes are made by adding water to the aqueous phase transferred and the organic solvent removed at the same time or subsequently completely or partially.

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In principle one can proceed in such a way that the salt the diaminosulfonic acid in aqueous solution and the isocyanate group-containing pre-adduct is stirred in. It it is also possible to combine all of the water with the salt of the diaminosulfonic acid with the pre-adduct containing isocyanate groups to add.

As' solvent for the isocyanate preadduct containing are preferably low-boiling organic solvent such as acetone, tetrahydrofuran, methyl ethyl ketone and ter- W tiäres butanol is used, and it is also quite possible to use water-immiscible, low boiling solvent such as benzene and methylene chloride.

As a solvent for the salt of diaminosulfonic acid, low-boiling alcohols such as methanol and ethanol or Water may be used with the addition of other organic solvents. The one containing isocyanate groups Pre-adduct is generally expediently prepared at higher temperatures, with the use of aliphatic Diisocyanate temperatures between 110 and 150 ° selected will. In the case of aromatic diisocyanates, it is generally sufficient 60-100 °. In the preparation of the pre-adduct Amount of polyisocyanate is preferably chosen so that all groups reactive with isocyanate groups react; about that In addition, a small excess of diisocyanates can be used. In general, the ratio of the isocyanate groups to the isocyanate-reactive groups no greater than 1.3-1.5.

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1942327

After the melt has cooled, the pre-adduct becomes with the organic Solvent added and at 20-80 ° with the optionally Diaminosulfonic acid salt present in solution is added. The pre-adduct can, if during its production Viscosities that are too high occur, even with the addition of solvents such as acetone, tetrahydrofuran or methyl ethyl ketone can optionally be prepared under pressure.

The proportion of sulfonate groups -S0 ₃ ^e in the polyurethane 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 removed by distillation or blowing out, e.g. at temperatures between 30 and 80 °. Preferably the solvent is removed in vacuo.

You can thus aqueous dispersions in the form of low to high viscosity, non-sedimenting latices with a medium Particle size between 0.02 and 1.0 u, preferably 0.05-0.2 u, and a solids content typically from 20-60 #.

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

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The dispersions generally dry at room temperature "". or higher temperatures directly to dimensionally stable films, and coatings on. Higher temperatures are preferred. The dispersions according to the invention come afterwards: are crosslinked, e.g. by polyfunctional, crosslinking agents Substances such as formaldehyde or formaldehyde releasing or how Formaldehyde reacting substances such as hexamethylolmelamine or carbamide resins, as well as phenolic resins, masked polyisocyanates or polyepoxides. Received impregnations and adhesive layers.

Dispersions according to the invention are mainly used as coatings and impregnations for a wide variety of sub-. strate such as paper, cardboard, textiles, leather, fleece, and wood Metals, used as adhesion promoters, binders and adhesives and for the production of threads, films and foils. The ones from the Molded articles, coatings and impregnations obtained from dispersions are characterized by good water and oil resistance and prove to be above all in accordance with the Belgian patent 673 432 using e.g. 2,4-diamino-benzenesulphonic acid desirably as colorless and lightfast.

The dispersions can be blended with anionic polymer or copolymer dispersions, for example of vinyl chloride, ethylene, styrene, butadiene, vinylidene chloride, vinyl acetate,! ■■■ acrylate and acrylonitrile. Fillers, plasticizers, pigments, powder, aluminum powder, bronze powder, clay, asbestos and ferric dispersions can also be incorporated into the dispersions.

Production of the diaminosulfonic acids to be used according to the invention '

A) Np.trium-1, o-diaminohexane-1-sulfonate. le A 12 440 \ -10-

109 8 10/2 101

The connection was made according to the Dutch patent specification 6,513,521 from butene-2-dinitrile 1,4 by addition of sodium bisulfite and subsequent catalytic hydrogenation.

B) Sodium 3- / 3-di- (3-aminopropyl) -amino-2-hydroxy-propox ^ 7-propanesulfonate.

171 g of allyl glycidyl ether are heated with 123 g iminodipropionitrile 16 hours at 95 ⁰ C. After the excess allyl glycidyl ether has been distilled off at a pressure of 1 Torr, 3-di- (2-cyanoethyl) -amino-2-hydroxy-propyl7-allyl ether (I) remains in quantitative yield as a pale 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 the aqueous solution is evaporated to dryness in a rotary evaporator in vacuo. There are 88 fo the theory of sodium 3 - ^ - di- (2-cyanoethyl) -amino-2-hydroxypropoxy_7-P ^r ° pansulfonat (II) obtained as an ointment-like mass.

260 g II are dissolved in 1000 ml of water and after addition of 250 ml of liquid ammonia in Gege Wart of 50 g of Raney cobalt at 150 at 90 ⁰ C and hydrogenated. 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. Sodium 3 ^ -di (3-aminopropyl) -amino-2-hydroxypropoxy_7-propanesulfonate is obtained in quantitative yield as a viscous mass.

H ₂ N- (CH ₂ ) ₃

/ N-CH ₂ -CH-CH ₂ -O- (CH ₂ ) 3 -H ₂ N- (CH ₂ ) 3 q _H

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Examples: Example It

250 g of adipic acid-ethylene glycol polyester (OH number 56) are dehydrated at 120 ° for 50 minutes and then reacted with 38 g of 1,6-hexane diisocyanate at 120 ° for 2 hours. This isocyanate groups containing pre-adduct is cooled to 55 ° and taken up with 650 ml of acetone. About this acetone pre-adduct solution a solution of 13.6 g is obtained with rapid stirring Sodium 1,6-diaminOhexane-3-sulfonate (prepared according to A) in Given 60 ml of water. Then 380 ml of water are stirred in. The batch is stirred until the streaks that initially appear have disappeared and the batch has become homogeneous is. The acetone is distilled off in a water jet vacuum at 55 °. 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.

Example 2;

425 g of adipic acid-1,6-hexanediol neopentyl glycol polyester (molar ratio 30:22 to 12; OH number 67) are dehydrated at 120 ° for 30 minutes and then reacted with 68 g of 1,6-hexane diisocyanate at 120 ° for 2 hours. The pre-adduct containing isocyanate groups is cooled and taken up in 1500 ml of acetone. 43 »6 sodium 3- / 3-di- (3-aminopropyl) -amino-2-hydroxy-propoxy_7-propanesulfonate (prepared according to B) in 120 ml of water are added to this pre-adduct solution. After brief stirring, 850 ml of water are added and the acetone is drawn off in vacuo. The dispersion obtained has a solids content of $ 33.4 and dries to give clear, colorless films with high tensile strength.

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η 1942827

Example 3;

250 g of adipic acid-ethylene glycol polyester (OH number 56) are dehydrated at 120 ° for 30 minutes and then mixed with 41 g of methyloyolohexane diisocyanate isomer mixture (isomer ratio of 2,4-diisocyanate: 2,6-diisocyanate 80; 20) for 2 hours 120 ° implemented. The prepolymer melt is cooled to 55 ° and taken up with 70 ml of acetone. A solution of 11.4 g of sodium 1,6-diaminohexari-3-sulfonate (prepared according to A) in 60 ml of water is added to the acetone solution with rapid stirring. Then 380 ml of water are stirred in and the acetone is distilled off in a water jet vacuum at 55 °. The dispersion obtained, with a solids content of 41.8%, dries to give smooth and firm coatings. .

Example 4;

The procedure is as in Example 3, however, instead of the polyester, 250 g of polypropylene glycol ether (OH number 56) are used , and the prepolymer reaction is carried out at 130 ° instead of 120 °. A stable dispersion with a pest body content of $ 39 is obtained, which upon drying provides a soft, slightly tacky film.

Example 5;

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

HOCH ₂ -Si (CH ₃ ) ₂ -0- / Si (CH ₃ ) ₂ o7i ₂ -Si (CH ₃ ) ₂ -CH ₂ OH

with a content of 2.7% OH are added after dewatering £> ei 120 ° at 90 °, with 79 g of 1,6-hexane diisocyanate and reacted at 100 ° for 2 hours for reaction. After cooling down

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if 1942S27

50 ⁰ C, the liquid reaction mass is taken up with 1000 ml of acetone and prepared with a solution of 36.5 g of sodium * -3- / 3 * di- (3-arainopropyl) -amino-2-hydroxy-propoxv.7-propanesulfonate ( according to B) added to 160 ml of water. After stirring for a short time, 600 ml of water are stirred in and the acetone is stripped off in vacuo. The dispersion obtained has a solids content of 4Q5 ia dries to a waxy film.

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Claims (2)

Claims l) Process for the preparation of aqueous, emulsifier-free, anionic polyurethane dispersions of polyurethanes obtained by the isocyanate polyaddition process with a content of 0.05-8 percent by weight of SO3 ⁸ groups (based on the dry polyurethane) by reacting higher molecular weight polyhydroxy compounds with a molecular weight of 300-20,000, polyisocyanates, optionally also to be used chain extenders with reactive hydrogen atoms and alkali or ammonium salts of diaminosulfonic acids and conversion in a manner known per se into aqueous dispersions, characterized in that the salts of diaminosulfonic acids are those of the general formula NH ₂ -ZX-Z'-NH ₂ SO _x Me, in which Z, Z ^{1 are} identical or different and are alkylene radicals and X = -CH- (m = 0) or N (m = 1), where Ζ, Ζ ', Χ together represent a cycloalkylene radical can and Y is an alkylene, hydroxyalkylene or hydroxyether alkylene radical and Me = Li, Na, K, Rb, Cs, NH ₄ , NHR ' ₃ , NH ₂ R' ₂ , NH ₃ R ¹ R ¹ = alkyl (C ₁ -C ₄ ), be used. 2. Polyurethane dispersions by the method according to claim 1. Le A 12 440 - 15 - 109810/2101