DE2252124A1 - DISULFIDES - Google Patents

Description

Badische Anilin- & Soda-Fabrik AG ooco-io /

ZZoZ 124

Our reference: O.Z. 29 478 Ze / UB

6700 Ludwigshafen, 19th 10th 1972

Disulfides

The invention relates to new disulfides, a process for their 'production and their use for vulcanizing rubber and synthetic rubber material.

One of the most important processing stages of rubber is As is well known, vulcanization, in which the rubber changes from the thermoplastic to the highly elastic state. It is given other physical properties, in particular better breaking strength, elongation at break, rebound resilience, Abrasion resistance, hardness and better resistance to solvents.

The implementation of the rubber with the vulcanizing agent, usually sulfur, decreases depending on the working conditions and the composition of the vulcanization mixture has a certain time course in which the properties develop and achieve their best values in a phase of optimum, only to return with longer vulcanization (over-vulcanization) to descend. A phase of the that is as insensitive as possible to fluctuations in the vulcanization temperature and duration Optimums (broad vulcanization plateau) is therefore a requirement of technology.

For vulcanization on an industrial scale is next an operationally reliable working method also the uniformity of the optimal property values to be achieved in each of the Pormartikel produced during operation, e.g. seals, shoe heels, as well as in each Part of a particularly large item, e.g. car tires, is important. By adding appropriate vulcanization auxiliaries, in particular vulcanization accelerators, to Vulcanization mixture and a suitable mixture composition can reduce the vulcanization time or one

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Lower vulcanization temperature can be made possible, but not all of the problems described in one for industrial operation can be solved in an economical manner.

A compound that has so far been able to solve this problem to a large extent is the well-known mercaptobenzothiazole and functional derivatives thereof, such as cyclohexylbenzothiazylsulfenamide.

However, these connections could not yet relate to all wishes the tension value, the strength, the elongation, the elasticity and the hardness, as well as the aging resistance to satisfy.

Ea new compounds of the formula I have now been found,

- N N-R

in the R one optionally in the 2-position by one Hydroxyl or oyanide group-substituted alkyl radical with 1 to 4 carbon atoms.

This new group of compounds also represents functional derivatives of the mercaptobenzothiazole mentioned, which are now surprisingly able to meet the above criteria in full.

The new compounds are prepared by known methods and are carried out in such a way that they are stoichiometric Quantities of mercaptobenzothiazole, a piperazine of the formula II

ΕΉ N - R II,

in which R has the same meaning as in formula I and brings sulfur dichloride to the reaction.

The initial product for the process according to the invention is this

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Mercaptobenzothiazole. The second starting product is composed of the piperazines substituted according to the above definition together, of which methylpiperazine, ethylpiperazine, propylpiperazine, Butylpiperazine and cyanoethyl and hydroxyethylpiperazine are to be mentioned separately. From a technical point of view, methyl, cyanoethyl or hydroxyethylpiperazine is of particular importance.

One molar equivalent of sulfur dichloride is added to these reactants present in a molar ratio. The reaction generally takes place without a solvent, but it is more advantageous to use solvents if they are inert towards the participants in the reaction, since this makes the removal of heat easier to handle. Expediently, such as a solvent whose boiling point is between 60 and 14O ⁰ C. Examples include chloroform, ethylene chloride, benzene, ethanol or tetrahydrofuran.

Specifically, one can, for example, proceed by suspending in the approximately five times the amount by weight of chloroform at ca, 20 to 30 ⁰ C. 1 part by weight of mercaptobenzothiazole and at the same temperature is added the equimolar amount of the piperazines as defined above and with stirring to a temperature between 0 and 10 ° C cools down. At the latter temperature, equimolecular amounts of sulfur dichloride are slowly added, for example dropwise. After about 1/2 to 2 hours of vigorous agitation, for example stirring, the solvent is distilled off under reduced pressure until a solid crystal mass appears. The crystal mass is taken up in a solvent such as benzene. Working up is then carried out in a manner known per se by washing out the benzene solution and drying. After removing the solvent, about 60 to 70 % of the theory of the desired disulfide are obtained.

The new substances allow the vulcanization of rubber in a wide range of applications in terms of working conditions and rubber goods in a simple and economical manner

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perform. For example, when using the invention Compounds that accelerate the vulcanization of natural rubber, fluctuations in the duration of the vulcanization or the temperature have a comparatively much broader effect compared to the previous state of the art Interval not or only slightly on the values of the various properties of the vulcanizates (broad vulcanization plateau). The N-substituted piperazyl-2-benzothiazolyl disulfides used in the vulcanization process can partially also improve the values of the various properties of the vulcanizates themselves, especially one achieve good aging resistance. Depending on the vulcanization conditions or the composition of the for this The substance mixture required for the process can be used in whole or in part as vulcanization accelerators, accelerator activators, Anti-aging and anti-fatigue agents and / or protective agents against atmospheric cracks are used.

A salient feature of the new substances according to the invention is that ^{very good crosslinking is achieved with them at temperatures of about 140 °} C. and more without auxiliary accelerators. At approx. 180 ^° G, a practically complete degree of crosslinking is achieved within a few minutes (approx. 1 to 4 minutes) with a good flow time, a very good plateau being obtained with little reversion.

This behavior of the new substances allows one thing above all very safe and fast processing process.

In general, the substances according to the invention are used in the vulcanization mixture in an amount of about 0.6 to 3, preferably 0.8 to 1.8 percent by weight on the amount of rubber by weight in the mixture.

The compounds according to the invention can be used for all types of rubber that can be sulfurized and vulcanized. But it can also be used during vulcanization with others Vulcanizing agents, e.g. thiuramdi- or tetrasulfides,

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be considered. In addition, synthetic rubbers, e.g. butyl rubber, ethylene-propylene rubber, Polymers based on butadiene styrene, butadiene acrylonitrile in the presence of the compounds according to the invention to be vulcanized.

In addition to the rubber, the vulcanizing agent and the inventive The material in the vulcanization mixture is usually the one depending on the intended use or processing Desired auxiliaries, e.g. blowing agents, reinforcing fillers, such as carbon black or silica, activating agents such as sink oxide or stearic acid, plasticizers such as mineral oils or Contain paraffins, substances which make them difficult to burn or which improve odor, or dyes. The invention Substances and other vulcanization accelerators, activator retarders, as well as anti-aging and / or anti-fatigue agents are used together in the composition will.

The vulcanization can be done in any way, for example in the multi-storey, autoclave, mouth, boiler or injection press with steam or hot air in the boiler or in continuous operation as with cable cores, in vulcanizing machines, as in the production of floor coverings, according to a Cold vulcanization process. In particular, all processing forms, machines, mixtures, temperatures, pressures and auxiliaries customary for vulcanizing natural rubber with sulfur can be used in vulcanization with the aid of the substances according to the invention. For more details on the composition of customary vulcanization mixtures to which the substances according to the invention are to be added, machines, types of processing, vulcanization conditions, reference is made to Gr. Alliger and IJ Sjothun, vulcanization of the elastomer (Reinhold Publishing Company, N Y. _0); A. Springer, Material Science (Fachbuchverlag Leipzig 1958); HJ; Stern, Rubber (Mac Laren & Sons Ltd., London) 1967, referenced, common vulcanization processes are also dealt with comprehensively in the rubber handbook by S. Boström Berliner Union, Stuttgart (1959).

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- b - O.Z. 29 476

The vulcanization can be for example carried out as follows: A Gemiach of natural rubber, sulfur, compound of the invention and optionally plasticizers, zinc oxide, and fillers, is vulcanized for 1 to 90 minutes at 120 to 25O ⁰ C in a press with steam and then the vulcanizate is the The press is removed and sent for further processing.

Vulcanization using the substances according to the invention is used for the production of a large number of rubber goods, in particular, all rubber products usually produced on the basis of natural rubber can be considered. E.g. can The following goods are produced in excellent quality: molded articles such as shoe heels, seals, cuffs, injection molded articles such as profiles, canning rings, sealing cords, tubular goods such as water hoses, sheet materials such as Sealing sheets, mats, floor coverings, conveyor belts, drive belts, rubber shoes, cables, foam and cellular rubber, hollow bodies such as seat cushions, hard rubber goods such as equipment linings or vehicle tires.

The parts given in the examples are parts by weight:

example 1 2-mercaptobenzothiazolyl-N-methyl-piperazyl-disulfide

170 parts of mercaptobenzothiazole are suspended in 750 parts of chloroform at 25 °; under stirring, at 25 C to N-methylpiperazine and cooled to 10 ⁰ C. At this temperature 103 parts of sulfur dichloride are added dropwise with stirring and cooling. After stirring for one hour at this temperature, the chloroform is i.Vac. distilled off, a yellow crystal mass being obtained. This is taken up in 500 parts of benzene, the benzene solution is washed twice with 500 parts of water each time and dried. After removing the benzene, 180 parts (= 63.4 ^ of theory) of 2-mercaptobenzothiazolyl-4'-methyl-piperazyl disulfide are obtained as yellow crystals.

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- Ύ - , (M = 297) 2 S. O.Z. 29 478 , 4 i> N 32, 2252124 , 1 io Ep. ' 114 - 11 5 ° C . 14.1 io 32, Analysis for G ₁₂ H ₁₅ N ₃ S ₃ 13.8 io 2-mercaptobenzothiazolyl-N'-hydroxyethyl piperazyl disulfide G H ber. 48.5 io 5, o io ■ found 48.9 io 5.3 io example

83.5 parts of mercaptobenzothiazole are suspended in 500 parts of chloroform. With stirring at room temperature 195 parts of N-hydroxyethyl piperazine were added, a clear solution being temporarily obtained. You cool down to approx. 10 G and at this temperature, while stirring and cooling, 51.5 parts of sulfur dichloride are added. The obtained clear The solution is stirred for 2 hours at 40 ° to 45 °, and the hydrochloride which has precipitated out after about 1 hour is dissolved in 250 parts of water taken up and the dried organic phase evaporated. 143 parts are obtained as residue (= 94.7 $ of theory) 2-mercaptobenzothiazolyl-N-hydroxyethyl-piperazyl-disulfide as a yellow, crystallizing melt which is obtained in crystallized form from 350 parts of benzene.

Ep. 131 - 133 ° G

G ₁₃ H ₁₇ ON ₃ S ₃ (M = 303)

G , 6 H 3 VJI 0 ok N 84 i> S. 7th Ber. 43 , 3 % 5.6 io 2 , 26 ok 13, ι Γ * 31, • VJl Found 51 $> 4.2% ,8th 10, 31, example

2-mercaptobenzothiazolyl-N-cyanoethyl-piperazyl-disulfide -

42 parts of mercaptobenzothiazole are suspended in 250 parts of chloroform. With stirring I04 parts of N-cyanoethyl-piperazine are added and the clear solution cooled to about 10 ⁰ G.

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While stirring and cooling 25.8 parts sulfur are added at 10 to 15 ° C and stirred for 3 hours at 40 to 45 ⁰ O. The precipitated hydrochloride is dissolved in 250 parts of water, the organic phase is separated off and, after drying, evaporated. The residue obtained is 82 parts (= 97.0 io of theory) of 2-mercaptobenzothiazolyl-li-cyanäth.ylpiperazyl disulfide as yellow crystals which are recrystallized from ethyl acetate.

Mp 122 -. 123.5 ⁰ O
^C 14 ^H 18 ^N 4 ^S 3 ^{(M = 538)}

G H N $ 6 S. , 4 Be r. 49.7 1 ° 5.3 $> 16, 28 , 2 Found 49.7% 4.7 % 15, 29 Example 4 The test mix x)
Smoked Sheets ' 100. HAF carbon black ^XX ^ 40 ZnO 5 Mineral oil plasticizers 3 sulfur 2

2 parts of N-Alkylpiperazyl-benzothiazolyl disulfide was added and tested this substance in Schwingelastometer (Viskotast Fa. Frank-Birkenau) at 140 ⁰ C and 180 ⁰ O.

Result s: 90 % 100 %
Vulcanization
min min 9 21 2 Shear modulus
at 100 %
Vulcanization.
mkp Incline
angle of
VuIk. Curve Tenn.
⁰ C Beginning
the
VuIk.
min 13, 0 4, 4th 0.94 79 ° HO 5.6 4, 0.69 87 ° 180 <1.0

x) thin rolled natural rubber
xx) according to ASTM "carbon black N 330"

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_ α _ 100 , 5 O.Z. 29 4γ8 - 40 , 5 2252124 Example 5 5 Me test report Smoked Sheets 3 HAP-RuS 1 ZnO 0 Mineral oil plasticizers Stearic acid sulfur

became A with 1.8 phr cyclohexyl-benzothiazylsulfenamide B with 1.8 phr N-methylpiperazyl-benzthiazolyl-disulfide

■ accelerates. The rubber technology test was obtained following physical data:

Vulcanization stress value

Strength kp / cm elongation fo elasticity Shore hardness ⁰ Sh

Aging voltage value

Strength kp / cm elongation%

Aging voltage value

Strength kp / cm elongation $

Compression set after

Method B 56 20.1 16.8

(30 OK deformation 24 hours at 70 ^° C)

It is clearly shown that the. Test substance provides better aging values and a better compression set.

A. B. 20 '/ 138 ⁰ G - 20 '/ 138 ⁰ G kp / cm 81 98 245 250 594 560 43 46 54 58 48 hours 100 ⁰ G A & hrs. 100 ⁰ G ρ
kp / cm 95 125. 190 206 463 440 100 hours 100 ⁰ G 100 hours 100 ⁰ G p
kp / cm 91 128 165 171 451 380

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Example 6

Use in styrene-butadiene rubber (SBR) a SBR 1500 ^x ^ 64.9 Carbon black N 220 26.0 zinc oxide 2.0 Stearic acid 1.3 Phenylbetanaphtylamine 0.6 aromatic emollient oil 3.2 sulfur 1.2 N-methylpiperazyl-benzo- thiazyl disulfide 0.8

100.0 The following results were achieved:

Scorch according to Mooney at 120 G ML-tj-min 16.5

Vulcanization 151 ° C / 3O min

Tension value 300 % strength elongation elasticity Shore hardness

x) degree of polymerization

Example 7 Application in nitrile rubber (NBR)

kp / cm 80 kp / cm 290 $> 600 K> 40 ° Shore A 59

Nitrile rubber 60.9 Carbon black N 330 (ASTM) 30.4 zinc oxide 1.8 Butyl phthalate 4.9 sulfur 1.2 N-methylpiperazyl-benzo-
thiazyl disulfide 0.8

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151 ° C / 30 min Example 8 Ö.Z. 29 47S 160 300 <fo 245 -M- 22W124 415 ML-tt- min 15 25th Mooney Scorch "at 1-20 * G A 68 vulcanization kp / cm Voltage value 0
kp / cm strength strain elasticity ° Saore Shore hardness

Butyl rubber 61.4 Carbon black IT 330 (ASTM) 31.0 zinc oxide 3.0 Stearic acid 0.4 Paraffin oil 1.8 sulfur 1.2 Tetramethylthiuram disulfide 0.6 N-methylpiperazyl-benzo- thiazyl disulfide 0.6

Scorch according to Mooney at 140 G Vulcanization 161 ° C / 3O min Tension value 300 fo Strength Elongation Elasticity Shore hardness

100.0

min

kp / cm ' ¹

kp / cm ^

Shore A

Example 9 Application in ethylene propylene rubber (EPDM)

Ethylene propylene rubber 45.0 Carbon black Έ 550 (ASTM) 36.0

Zinc oxide 2.2

175

660

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naphthenic emollient oil

Stearic acid

sulfur

Mercaptobenzothiazole

N-methylpiperazyl benzothlazyl disulfide

Dipentamethylene thiuram tetraulfide

Tellurium diethyl dithiocarbamate

Scorch according to Mooney at 160 ^° C

Vulcanization 158 ° C / 2O min. Tension value 200 i> strength

strain

elasticity

Shore hardness

o.z. 29 478 13.5 7.2 2252124 0.7 111 0.7 HO 0.7 300 0.5 40 0.35 75 0.35 100.00 ML-tp- min kp / cm kp / cm 96 ok ° Shore A

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Claims (4)

Claims 1. Compounds of formula I in the R one optionally in the 2-position Hydroxyl groups or cyano groups substituted alkyl radical with 1 to 4 carbon atoms. 2. Compound of the formula I in which R is a methyl group. 3. Process for the preparation of compounds according to Claims 1 or 2, characterized in that stoichiometric amounts of mercaptobenzothiazole, a piperazine of the formula II H-ITN-R (II), in which R has the same meaning as in formula I, and brings sulfur dichloride to the reaction. 4. Use of compounds according to claim 1 or ^, as a curing aid. Badische Anilin- & Soda-Fabrik AG- 409818/1190