DE1179660B - Coating compositions which form highly elastic films, in particular rubber lacquers based on sulfur-containing polyurethanes - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school KI .: C 09 d

Number:
File number:
Registration date:
Display day:

German class: 22h-3

H 42344IV c / 22 h
April 19, 1961
October 15, 1964

It is known that from hydroxyl-containing polyesters and polyisocyanates, polyurethane coatings for Rubber coatings can be made. Such paints have because of the susceptibility to hydrolysis Ester groupings have only limited resistance to hydrolyzing agents. Also show Such rubber lacquers made from polyesters often have insufficient elasticity and poor adhesion and poor flow properties when applied to rubber surfaces.

For the production of polyurethanes, polythioethers containing hydroxyl groups have been used for a long time used by polycondensation of thiodialkylenes or by mixed condensation of glycols with thiodialkylenes in a ratio of 1: 1 to 1: 1.5 * 5 develop. The glycols used have a maximum of 6 carbon atoms. The one after this Polyurethane paints produced by processes do not show the susceptibility to hydrolysis as those made from hydroxyl groups Polyesters built up, but leave in terms of elasticity and flow properties to be desired. In addition, polythioethers containing hydroxyl groups are formed during the production By-products as a result of ring formation, which give the resulting products a bad odor.

In addition to polyesters, polysulphides, which are a multitude of these, are also used for the production of rubber varnishes contained by sulfur bridges. Such lacquer compositions only last one Elongation of about 100%.

It has now been found that coating compositions based on sulfur-containing polyurethanes are also improved mechanical properties, especially with good adhesion to rubber with high elasticity and good flow properties of the coatings, can be obtained by the fact that one for the production of sulfur-containing polyurethanes as polyisocyanate components, addition products of polyvalent isocyanates of a) dimeric or trimeric fatty alcohols and / or b) alcohols obtained by Guerbet condensation dimeric fatty alcohols have arisen, and / or c) etherification products of the aforementioned alcohols with thiodialkylenes, the molar ratio of polyhydric alcohol to thiodialkylene being approximately between 1: 0.9 and 1: 0.5 is used and / or that the alcohol component for the preparation of the sulfur-containing polyurethanes used the aforementioned etherification products with the proviso that at least one of the two components, d. H. So the alcohol or its ethereal product or the polyisocyanate contains sulfur.

Highly elastic film-forming coating agents,
in particular rubber lacquers based on
sulfur-containing polyurethanes

Applicant:

Henkel & Cie. G. m. B. H.,

Düsseldorf-Holthausen, Henkelstr. 67

Named as inventor:

Dr. Horst-Jürgen Krause,

Düsseldorf-Holthausen,

Dr. Manfred Dohr, Düsseldorf

The following are the two components for making the sulfur-containing compounds of the present invention Polyurethanes described:

A. The isocyanate component

The isocyanate components are the polyisocyanates, which are formed by the addition of di- or polyisocyanates to certain higher branched polyhydric alcohols are obtained.

Isocyanates known per se are used as di- or polyisocyanates, preferably aromatic diisocyanates, ζ. B. tolylene diisocyanate. In many cases, such aromatic diisocyanates are suitable for which the reactivity of the isocyanate groups is increased or decreased by substituents, z. B. the dianisidine diisocyanate and other aromatic diisocyanates, as described by W. S i e f k e η in Liebigs Annalen, Vol. 562 (1943), pp. 75 ff., Are described.

As branched higher polyhydric alcohols, dimeric and trimeric fatty alcohols or mixtures thereof can be used It is known that such fatty alcohols can be used by catalytic hydrogenation of dimers or trimeric fatty acids or their esters are obtained. You are also z. B. by dimerization accessible to unsaturated fatty alcohols. Since the fatty acids or fatty alcohols used as starting materials usually contain 18 carbon atoms, diols or triols with 36 or 54 carbon atoms. For the process according to the invention, commercially available technical Mixtures of these dimeric and trimeric fatty alcohols can be used. Such mixtures show im generally a content of about 80% of dimeric and about 20% of trimeric alcohols. Of course pure dimeric fatty alcohols can also be used

409 707/342

3 4

(for the production of the poly- sets to be used, the sulfur-containing isomers described above Fatty alcohols see U.S. Patent 2,347,562). to use cyanate component. Of course

Higher polyhydric alcohols can also include both the isocyanate component and

molecular branched triols in question, which from the alcohol component the thiodimers described above Contain fatty alcohols with the help of the so-called 5 ether grouping.

Guerbet condensation with leakage of water and mole- Furthermore, it is possible to use the invention

külver-doubling can be obtained. sulfur-containing alcohol component with a known

In addition, polyisocyanate components can be used as polyhydric alcohols for the th polyisocyanate component. In the end

Production of the polyisocyanate component Veräthe- one can also the sulfur-containing according to the invention tion products from the above-described polyisocyanate component with a different known

Alcohols and thiodialkylenes are used. React the th alcohol component.

Suitable thiodialkylenes are, for. B. thiodiglycol or those described above as the isocyanate component

other aliphatic thiodialkylenes, such as 3,3'-dihydroxy reaction products from di- or polyisocyanates

Dipropyl sulfide, 4,4'-dihydroxydibutyl sulfide or aro- and thioether alcohols can also be used as single-component aliphatic Thioether glycols such as 1,4 - (/ J-hymenene lacquers are used. The hardening takes place in

hydroxyethyl) phenylenedithioether. in this case by the action of water, preferably

The etherification of the above described several times in the form of steam or air humidity, in on

valued, branched alcohols with the thiodialkyl- in a known manner with the formation of urea-

Oiling takes place according to known, here not grouping.

claimed methods, for example by heating in 20 For the production of two-component paints

a higher-boiling solvent, which is equal to the alcohol component with at least the stoichio-

A metric amount of the isocyanate component is added early as an entrainer for the water produced,

serves, and with the addition of acidic catalysts, such as. However, an excess of isocyanate compo-

p-Toluenesulfonic acid, benzenesulfonic acid, phosphorus can be used. The isocyanate component

acid, zinc chloride or the like. The molar ratio of 25 is here generally in an indifferent

Alcohol to thiodialkylene is between 1: 0.5 and solvents, e.g. B. ethyl acetate, methylene chloride, ben-

1: 0.9. This means that the alcohol component is dissolved in zol, toluene, xylene, dioxane. The amount of

Excess is present. Solvent can vary significantly. The alcohol

The new thioether and isocyanate components obtained in this way become functional alcohols differ from known thioethers- 30 only shortly before the application of the coating alcohol by means of a lower content of sulfur. Depending on the isocyanate and a highly branched carbon structure. component, the pot life of the obtained On this configuration the thioether alcohols are coating agents at room temperature between one according to the inventor, the favorable properties half an hour and a few hours. For the production The isocyanate component of the polyairethane paints produced therefrom can also be added slowly to lead. Such thioether alcohols are preferably used or reactive aromatic isocyanates used, which has a molecular weight between about 1200 you can this isocyanate component by plant and 6000, preferably 1800 to 3000. tion of bisulfite or phenol or other easily ab-the latter if you mask them as starting materials for fissile compounds. Such mixtures the method according to the invention used, especially 40 have a considerably longer pot life. Partially highly elastic films. they can be stored for a long time at room temperature.

For the preparation of the polyisocyanate component, mixtures of this type are also known to be known as monomers the aforementioned di- or polyisocyanates are referred to as component paints. The hardening takes place in the described polyhydric alcohols or thio- in this case by the action of heat, ether alcohols or mixtures of these compounds implemented in a manner known per se, component being a small amount of a tertiary amine the proportions are chosen so that to be added as an accelerator, especially in the case of room one OH group preferably about two isocyanate temperature to shorten the curing time. Suitable meet groups. Accelerators are, for example, triethylamine, N-Me-

^ _. . "," 50 thylmorpholine, dimethylaminoethanol, tertiary amines B. The alcohol component

The coating compositions prepared according to the invention are preferably used as the alcohol component Above as starting materials for the production of the Iso- can with particularly good success for the painting cyanate component described di- and poly- of rubber are used. They form high alcohols or their glossy, very elastic and abrasion-resistant paint films described under c) above, ethereal products with thiodialkylenes are used. The highest strength for the production of the sulfur values according to the invention is achieved.

The elasticity and hardness of the paint film, the nents, there are several possibilities, since both the degree of crosslinking of the resulting sulfur-containing and sulfur-free polyisocyanates depends, among other things, on the polyurethane film that can be used by the mole. If the sulfur weight of the starting materials is used and the more free polyisocyanates are used, the higher molecular weight thioether alcohol component described is used as the alcohol component or the higher molecular weight thioether alcohol component described is varied to a lesser extent. If, on the other hand, the above mentioned _{4 TT are used} . ..., _It "written sulfur-containing polyisocyanate component, 6 _{5 A T} ^A :" f "^ L claimed production, a sulfur-free alcohol ^{component of the} thioether alcohols can also be used by known methods. In an analogous manner, in cases in a) In a reaction vessel with a reflux condenser, which contained a sulfur-free alcohol component. Water separator and stirrer were 744 g of one

dine fatty alcohol with 20% trimer content (OH- a 75% solution of the prepared according to B, a)

Number 199) mixed with 122 g of thiodiglycol (molar ratio of polyisocyanate by vigorous stirring.

1: 0.83) in the presence of 500 cm ³ of xylene as towing To this was still 0.25 cm ³ of a 10% ^en triethyl-

added medium with 5 g of p-toluenesulfonic acid as a catalyst in the amine solution in ethyl acetate as a catalyst. With

Nitrogen stream heated to boiling, whereby the stripes of the lacquer solution thus obtained were removed

cracked water was continually removed. After the tire rubbers have been coated with gasoline,

The elimination of water was complete, the reaction was cleaned. The painted rubber strips

mixture cooled. The catalyst was still using after evaporation of the solvent

alcoholic sodium methylate solution is neutralized and post-cured for 2 hours at 120 ⁰ C. After this

Fuller's earth added. The solution was then cured and obtained on the rubber surface

Stir again briefly heated and then dry, highly elastic and abrasion-resistant paint film,

filtered. Then the solvent in the water became solvent-resistant and insensitive

Distilled off jet vacuum. It left a yellow color against hydrolyzing agents. 20% sodium bicarbonate

colored viscous oil with the following key figures: alkali and 20% nitric acid caused after

OH number 61.2; Molecular weight 2019; Viscosity no change at 75 ⁰ C 15 24 hour exposure at 25 ° C

441.5 cP (measured in a Höppler viscometer). of the film.

b) In the apparatus described above, b) 6.05 g of the 612 g of dimeric fatty alcohol (with 25% trimer content; according to A, b) prepared thioether (OH number 96.5; OH number 206) were mixed with vigorous stirring 67 g of thiodiglycol (molar ratio molecular weight 1310) mixed with 15.2 g of a 75% solution 1: 0.55) in the presence of 2 g of p-toluenesulfonic acid and 20 of the polyisocyanate prepared according to B, a). 500 cm ^{3 of} xylene as an entrainer in a stream of nitrogen. In addition, 0.25 cm ³ of 10% strength triethyl was heated to the boil until the separation of water was complete. An amine solution in glacial acetic acid was added as a catalyst. With was. Subsequently, methylate solution purified with toluene was neutralized with alcoholic sodium, the resulting solution was neutralized, bleaching earth was added and tire rubber strips were coated. The lacquered rubber filtered. Were stripes After distilling off the solvent under 25 after evaporation of the solvent, a water jet vacuum a yellow viscous oil was post-cured for 2 hours at 12O ⁰ C. It was received a. Key figures: OH number 96.5; Molecular weight of dry, elastic and well adhering lacquer film 1310; Viscosity at 75 ^° C. 228 cP (measured in the obtained. The hydrolysis resistance and Wider-Höppler viscometer). Resistance to caustic soda and nitric acid

30 corresponds to the paint produced according to Example 1, a).

B. Production not claimed here _{c) 9 2 of the thioether according to A a)} nergeste iiten

the polyisocyanate component according to known (OH number 61.2; molecular weight 2019) were 19.7 g

Methods of the 75% polyisocyanate produced _{according to B> ^}

a) 34.8 g (0.2 mol) of toluene diisocyanate were mixed in the solution by vigorous stirring. 0.25 cm ^{3 of} 10% strength triethylamine solution in anhydrous dimeric fatty alcohol (with 20% triester as catalyst 203) - in 30 g of anhydrous solution, cleaned rubber strips were coated with ethyl acetate dissolved - used. These micro and, after evaporation of the solvent two hours research was post-cured for 1 hour for secondary reaction at 70 ° C at 120 ⁰ C. One obtained on the gumming heat. The approximately 75% solution of the dry, elastic and resistant polyisocyanate obtained in this way was used as an isocyanate component for a stable paint film.

used in the production of the coating agents. Based on d) With the isocyanate solution obtained according to B, c)

on the solids content contained the solution obtained were cleaned rubber strips of tire rubber 11.17% isocyanate groups. coated. The painted rubber strips were after

b) A Guerbet alcohol 45 was used for this reaction. Evaporation of the solvent at 100 ° C. for 2 hours was used, which had an OH number of 162 and was put in a drying cabinet with a bowl of water Reaction from a pure dimeric fatty alcohol with set up, hardened. After this treatment the OH number of 206 had been established. 69.3 g one receives a hochdes on the rubber surface Guerbet alcohol was in 35 g of anhydrous elastic, well-adhering and resistant Ethyl acetate dissolved and under nitrogen atmosphere 50 film.

Sphere with 35 parts by weight of toluene diisocyanate for another sample was still 1% of a 10% strength

Brought reaction. The solution was then a catalyst solution of dimethylaminoethanol in heated to 70 ° C. for a further 1 hour and contained about toluene added and the rubber strip 48 hours 75% solids with 8.05% isocyanate groups. at room temperature and 80% humidity

c) hardens to a solution of 8.4 g of toluene diisocyanate 55. It took about 7 days until it was completely dry (0.0482 mole) in 29 g of toluene was required under nitrogen.

atmosphere a solution of 50 g (0.0482 equivalents) Example 2
a thioether prepared analogously to A, a) from a technical dimeric fatty alcohol and thiodiglycol 10.9 g of the thioether alcohol prepared according to A, a) alcohols (OH number 54) in 29 g of toluene at a temperature of 60 were in 19.9 g Dissolved anhydrous toluene and added dropwise at a temperature of 6O ⁰ C with stirring. After 18.7 g of the polyisocyanate adduct according to B, a) (1.7 meq reaction, the solution was held for 1 hour at 6O ⁰ C. isocyanate per gram) and 0.1 g of N, N-dimethyl

ethanolamine added. With the varnish thus obtained

Example 1 solution were made after degreasing with toluene strips

Production of the coating agent ⁶ S natural rubber vulcanizate, nitrile rubber vulcanizate

⁶ (Perbunan), soft polyvinyl chloride, polyethylene

a) 9.2 g of the thioether terephthalate prepared according to A, a), with a flame-pretreated poly-

(OH number 61.2; molecular weight 2019) were coated with 15.2 g of ethylene and rawhide. After evaporation

of the solvent, the coatings were ^{cured at 100 °} C. for 2 hours. Glossy, firmly adhering and elastic coatings were obtained on all films.

Example 3

A paint mixture of the following composition, which is customary for vulcanized rubber, was produced:

2 g branched polyester made from adipic acid, triol and butylene glycol (Desmophen 1200, registered trademark),

10 g linear polyester made from adipic acid and ethylene glycol (Desmophen 2100, registered Trademark),

10.3 g of addition product of tolylene diisocyanate with trimethylolpropane in a ratio 3: 1 (Desmodur L, registered trademark),

17 g toluene, anhydrous,
0.25 g of dimethyl ethanolamine.

With this lacquer mixture, test strips were made

Natural rubber vulcanizate and commercially available nitrile rubber vulcanizate 100 χ 20 χ 1 mm in size. After the solvent has evaporated the strips were cured at 100 ° C. for 2 hours.

In addition, test strips made of the same materials measuring 70 45 χ 1 mm in the treated the same way.

For comparison, additional test strips were placed in the

ίο the same way with a paint mixture according to the example 1, a) coated.

The test strips obtained measuring 100 × 20 × 1 mm were tested in a tensile strength testing machine with a feed rate of 150 mm / min, stretched, until there were changes in the paint layer. The test strips measuring 70 χ 45 χ 1 mm was examined for permanent elasticity through buckling in a Bally flexometer. the Findings are summarized in the table below.

20 posed.

material Paint-
mixture
after
example Stress Finding Natural rubber vulcanizate
Nitrile rubber vulcanizate (Perbunan) 3
l, a)
3
l, a)
3
l, a)
3
l, a) 278% elongation
443 ° / ₀ elongation
3000 flexometer folds
3000 flexometer folds
323% elongation
323% elongation
3000 flexometer folds
3000 flexometer folds
70,000 flexometer kinks Removal of the paint
small transverse cracks
Removal of the paint
small cracks
Transverse cracks
small transverse cracks
Removal of the paint
Paint unchanged
small cracks

Material breakage was observed in some samples.

Claims (2)

Patent claims: 1. Coating compositions which form highly elastic films, in particular rubber lacquers, based on sulfur-containing polyurethanes, characterized in that that they contain such sulfur-containing polyurethanes for the preparation of which addition products are used as polyisocyanate components of polyvalent isocyanates a) dimeric or trimeric fatty alcohols and / or b) alcohols which have arisen from dimeric fatty alcohols by Guerbet condensation, and / or c) etherification products of the aforementioned alcohols with thiodialkylenes, the molar ratio from polyhydric alcohol to thiodialkylene is approximately between 1: 0.9 and 1: 0.5, has used, and / or that the alcohol component for the preparation of the sulfur-containing polyurethanes the aforementioned di- and polyalcohols (a and b) or their abovementioned etherification products (c) are used has with the proviso that at least one of the two components, i. H. so the alcohol or its etherification product or the polyisocyanate contains sulfur. 2. Coating agent according to claim 1, characterized in that thiodiglycol is used as thiodialkylene is used. Considered publications: German Patent No. 756 058; German Auslegeschriften Nos. 1 006 146, 1 050 474, 1040 230; French Patent No. 1,168,071; U.S. Patent No. 2,870,112; British Patent No. 769 091; Brochure from the paint factories Bayer Akt. Ges. Über Desmodur / Desmophen, 1956, p. 17. 409 707/342 10.64 © Bundesdruckerei Berlin