DE1013866B - Vulcanization accelerator - Google Patents

Description

GERMAN

It has been found that very valuable vulcanizates are obtained if the vulcanization mixture is used 2,5-Dimercapto-1,3,4-thiadiazole of the formula

N—
HS-C

C-SH

Vulcanization accelerator

Applicant:

Aniline & Soda Factory in Baden
Aktiengesellschaft, Ludwigshafen / Rhein

or especially its derivatives in which one or both hydrogen atoms are substituted, or mixtures the same as an accelerator.

It is already known to vulcanize rubber using amine salts of 2-mercapto-5-thione-1,3,4-thiadiazolines arylated on the nitrogen atom. These are not actual vulcanization accelerators, but only activators that are used together with vulcanization accelerators and then increase the effect of the accelerator. These compounds differ from the 2, 5-dimercapto-l, 3, 4-thiadiazoles in that they have one less double bond in the ring and also one arylated ring nitrogen atom. The claimed compounds are excellent vulcanization accelerators even in the absence of activators. The rubber vulcanized with their help has tear strengths averaging about 245 to 270 kg / cm ² , while the known process only gives tear strengths between about 145 and 170 kg / cm ^2. Furthermore, the "plateau" of the 2,5-dimercapto-1,3,4-thiadiazoles is particularly good.

Particularly favorable substituents in the 2,5-Dimercapto-l, 3,4-thiadiazoles are in particular cycloalkyl radicals or straight-chain or branched alkyl radicals, which in turn can be substituted by halogen, oxy, carboxyl or amino groups. Also aralkyl radicals, z. B. styryl or benzyl, and their substitution products, heterocyclic radicals and unsubstituted or by oxy, amino, aliphatic, carboxyl, nitro, methoxy, acylamine, sulfonic acid or similar groups substituted aryl radicals can be present as substituents. It is particularly advantageous to use monosubstituted 2, 5-Dimercapto-l, 3, 4-thiadiazoles, which are used to increase their effectiveness in their organic or inorganic salts, e.g. B. in their Zn salts, or by means of oxidizing agents, e.g. B-. Hydrogen peroxide, Alkali hypochlorites, halogens or persulfates, in their disulfides or with the help of primary or secondary Can convert amines into their sulfenamides in the presence of the oxidizing agents mentioned.

For the preparation of salts of unsubstituted or monosubstituted dimercaptothiadiazoles, which is not claimed here one preferably starts from aliphatic, cycloaliphatic or aromatic primary or secondary amines or heterocyclic NH compounds. The salts are produced by reaction Equimolar amounts of a dimercaptothiadiazole and an amine in the melt, in aqueous solution or in Indifferent organic solvents at temperatures between -5 and 180 °. By application an excess of a reaction component can accelerate the reaction.

Dimercaptothiadiazole or his are used for the production of sulfenamidefc, which is also not claimed here Monosubstitution products or their disulfides with equimolar amounts of an amine and with oxidizing acting means around, z. B. with alkali hypochlorites, halogens or hydrogen peroxide. Such amines are z. B. primary amines, but preferably secondary amines. The reaction is carried out in aqueous medium with or without Addition of inert organic solvents carried out. She is already walking at normal temperature but can also be accelerated by heating.

Mercaptothiadiazole and its substitution products and especially the organic salts of the monosubstituted 2, 5-Dimercapto-l, 3,4-thiadiazoles are very fast-acting vulcanization accelerators. You will be the Vulcanization mixtures are added in amounts preferably from 0.7 to 2.5%, calculated on the raw rubber.

The mechanical values of the vulcanizates are very good. Particularly noteworthy are the excellent plateau, d. H. the mechanical constancy, which is largely constant despite the variation in the vulcanization temperature and duration Properties, and the good aging resistance of the vulcanizates, so that individual compounds at the same time Vulcanization accelerators and anti-aging agents for rubber are.

The following dimercaptothiadiazole derivatives were tested as vulcanization accelerators:

709 657/443

1 013 866 4th 3 . Table 2 Table 1

2-2'-dithio-bis- [5- (2-ethyl-n-hexyl) -mercapto-1,3,4-thiadiazole]. Yellowish oil.

2-2'-dithio-bis- (5-n-octylmercapto-1,3,4-thiadiazole). F = 74 °.

2-2'-dithio-bis- (5-benzylmercapto-1,3,4-thiadiazole). F = 90 to 91 °.

Cyclohexylamine salt of 2-benzylmercapto-5-mercapto-1, 3, 4-thiadiazoles. F = 111 °.

Cyclohexylamine salt of 2- (2-ethyl-n-hexyl) -mercap- ^X 5 to-5-mercapto-1,3,4-thiadiazole. F (thiadiazole) = 55 °.

Cyclohexylamine salt of 2-methylmercapto-5-mercapto-1, 3, 4-thiadiazoles. F = 45 to 48 °.

Cyclohexylamine salt of 2-p-ethylbenzylmercapto-5-mercapto-l, 3, 4-thiadiazoles. F (thiadiazole) = 135-136 °.

Cyclohexylamine salt of 2-p-isopropylbenzyl mercapto - 5 - mercapto -1,3,4-thiadiazoles. F. (Thiadiazole) = 114 °.

Dicyclohexylamine salt of 2-p-ethylbenzylmercapto-5-mercapto-l, 3, 4-thiadiazoles.

Dicyclohexylamine salt of 2-benzylmercapto-5-mercapto-1, 3, 4-thiadiazoles.

p-Amino-diphenylamine salt of 2- (2-ethyl-n-hexyl) -mercapto-5-mercapto-l, 3, 4-thiadiazoles.

Bis-p, p'-diamino-dicyclohexyl-methane salt of 2-benzylmercapto-5-mercapto-l, 3, 4-thiadiazoles.

A mixture of 100 parts of smoked sheet, 1.5 parts of stearic acid, 10.0 parts of zinc oxide, 3.0 parts of sulfur and 0.8 parts of one of the proposed accelerators were used.

The vulcanizates produced with the aid of the dimercaptothiadiazole derivatives mentioned were according to the conventional methods tested for their mechanical properties. The following table gives a summary of the test results.

Dimer heater module
300% Tear
strength Tear
strain Back
bulging
elasticity capto- thia-
diazole
derivatives No. from 6O7I33 ° 9 148 807 60 Table 1 6O7I33 ⁰ 10 165 792 62 1 6O7I33 ⁰ 13th 174 659 63 2 6O7I33 ⁰ 27 240 654 72 3 6O7I33 ⁰ 27 229 632 73 4th 6O7I33 ⁰ 25th 245 676 71 5 6O7I33 ⁰ 25th 272 710 71 6th 6O7I33 ⁰ 23 236 690 68 7th 607133 ° 21 239 730 68 8th 6O7I33 ⁰ 21 238 725 67 9 607133 ° 13th 209 816 62 10 6O7133 ⁰ 14th 198 800 65 11 12th

The following table shows the very good plateau of the new accelerators:

Vulcanization

25th Dimer heater Table 3 Tear
strength Tear
strain Back
bulging
elasticity capto- thia-
diazole
derivatives No. from 207111 ° module
300 ⁰ Z ₀ 170 870 58 Table 1 3O7III ° 234 854 59 4th 457111 ° 246 800 68 4th 607111 ° 8th 270 764 63 35 4 207133 ° 11 242 747 70 4th 407133 ° 13th 265 706 71 4th 607133 ° 16 240 654 72 4th 807133 ° 17th 214 640 70 40 4 22nd 4th 27 25th

Some of the new compounds can also be used as anti-aging agents. the The following table shows the test values of the vulcanizate produced with compound no. 12 in Table 1 compared to those of a mixture vulcanized with 2-mercaptobenzothiazole. The aging takes place through 14-day treatment with warm air at 70 °.

Tabel

Vulcanization accelerator heater module
300 »/" strength strain Small
strain elasticity hardness 2-mercapto-benzothiazole
unaged 607133 °
607133 °
6O7I33 ⁰
6O7I33 ⁰ 17th
22nd
14th
15th 189
19th
198
145 770
260
800
752 28
3
30th
10 66
62
65
54 40
40
40
35 2-mercapto-benzothiazole
aged No. 12 unaged
Aged No. 12

Claims (1)

PATENT CLAIM: Process for vulcanizing rubber, characterized in that 2, 5-dimercapto-l, 3,4-thiadiazole or its derivatives in which one or both of the hydrogen atoms are substituted as a vulcanization accelerator be used. References considered: U.S. Patent Nos. 2,378,269, 2,382,524. I 709.557 / 443 8.57