DD270302A5 - N, n'-substituted bis- (2,4-diamino-S-triazin-6-yl) tetra-sulfides and their disproportionation products, process for their preparation and their use in vulcanizable rubber mixtures - Google Patents

Abstract

The invention relates to a process for the preparation of N, N-substituted bis (2,4-diamino-s-triazin-6-yl) tetra-sulfides. According to the invention, compounds of the general formula are prepared in which: R1, R2 is H; R 2 is benzyl, R 2, R 3, R 4 is C 1 -C 8 -alkyl, allyl, C 3 -C 8 -cycloalkyl, the latter unsubstituted or substituted by 1 to 3 methyl groups, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl or R 3 and R 4 (together): C4-C6 alkylene, (CH2CHX) 2 Y with XH, CH3; YO, as well as their oligosulfidic disproportionation products, whose mean statistical chain length corresponds to S4. formula

Description

Field of application of the invention

The invention relates to a process for the preparation of N,N'-substituted Els-(2,4-diamino-s-triazin-6-yl)-tetrasulfides, processes for the preparation of their disproportionation products, the use of the tetrasulfides and the disproportionation products as crosslinking agents or vulcanization accelerators in rubber mixtures and vulcanizable rubber mixtures containing them.

The rubber mixtures according to the invention are used in tire construction, for the production of conveyor belts, V-belts, molded articles, hoses with and without inserts, roller rubber linings, linings, injection molded profiles, films, shoe soles and uppers, cables, etc.

Characteristics of the known state of the art

N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl) disulfides are known; they are described in German Patent 1669 954. They are prepared from the corresponding N,N'-substituted 2,4-diamino-6-mercaptotriazines by oxidation, for example, with iodine, sodium hypochlorite, or hydrogen peroxide. The best-known compound in this group is bis-(2-ethylamino-4-diethylamino-triazin-6-yl) disulfide. Disulphides of this group can be used as accelerators in rubber compounds.

The rubber processing industry has access to a wide range of accelerators (J. van Alphen, Rubber Chemicals [1977, pp. 1-46]), primarily for sulfur vulcanization, such as benzothiazolylsulfenamides, benzthiazolyl disulfide, and 2-mercaptobenzothiazole or their zinc salts. There are also a number of special compounds, such as thiuram disulfides and feroxides, which act as crosslinkers even without the addition of sulfur, but are often used as accelerators in combination with sulfur. The type of application depends on the desired effect.

Benzthiazolylsulfenamides are currently the most important in practical applications, especially in elastomers that are accessible to accelerated sulfur vulcanization.

However, due to new production processes and new articles and the need for constant rationalization in recent years, the requirements for the use of accelerators have changed to such an extent that it can now be difficult to meet the quality requirements for the vulcanization process and the properties of the vulcanizates with the accelerators or crosslinkers available today for accelerated sulfur vulcanization.

Another disadvantage of some conventional accelerators (e.g. some sulfonamides, thiurams) that can no longer be ignored today is that amines can be released during the vulcanization process, which—if they are nitrosatable—lead to the formation of nitrosamines in the vulcanizate, which—if they are toxic—may limit the possible applications of these accelerators in the long term.

A significant disadvantage of benzothiazolyl accelerators, especially benzothiazolyl sulfenamides, is their increasingly pronounced tendency toward reversion with increasing vulcanization temperature due to the inevitable overheating of the vulcanizates, especially when using rubbers that are already susceptible to reversion, such as natural rubber and polyisoprene, as well as their blends with synthetic rubbers. The same applies to all types of synthetic rubber, provided the reversion process is not masked by thermal crosslinking. Particularly with increasing vulcanization temperature, the reversion rate increases so sharply that, firstly, there is a noticeable reduction in crosslink density even with optimal vulcanization; secondly, the vulcanization optimum takes on the form of a peak instead of a plateau, making the reproducible maintenance of optimal vulcanizate properties extremely difficult; and thirdly, with the over-vulcanization that is often necessary, an unavoidable drop in crosslink density occurs, which, particularly in thick-walled rubber articles, leads to the loss of uniform crosslinking in the vulcanizate. As reversion increases, so does the performance of the vulcanizates, which manifests itself, for example, in reduced 300% modulus and abrasion resistance, etc.

To a certain extent, reducing the sulfur content and increasing the accelerator content, i.e., the use of so-called semi-EV systems (L. Bateman, 1963, "The Chemistry and Physics of Rubber-Like Substances," p. 522 ff.), leads to a mitigation of the described reversion effects. However, this mitigation of reversion is achieved by changing the crosslinking structure (ratio of -S _x -, -SS-, -S- bonds) in favor of monosulfidic crosslinking sites, which can adversely affect the vulcanizate properties. However, this measure becomes increasingly ineffective the higher the vulcanization temperature is set.

These disadvantages of benzothiazole accelerators limit their applicability with increasing vulcanization temperature and place certain limits on the rubber industry's efforts to increase productivity by using higher vulcanization temperatures.

Aim of the invention

The aim of the invention is to provide compounds that improve the vulcanization behavior of rubber compounds and impart better properties to their vulcanizates.

Explanation of the nature of the invention

The invention is based on the object of finding new compounds with the desired properties and processes for their preparation.

-3- 270 302

According to the invention, compounds of the general formula

^{R3 R4}

N 'N n «, Aj, S ₄ -Xh \ _r 2 (I) prepared, in which mean:

R',R ² r ² ,r ³ ,r ⁴ = H, R ² = Benzyl = Cj-Ce-alkyl, preferably Cj-C ₄ -alkyl, branched or unbranched, alkyl, C1-Ce-cycloalkyl, the latter unsubstituted or substituted by 1-3 methyl groups, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl or R'andR ⁴ (together): C<-C ₈ -alkylene,-(CH2-CHX)2 Ywith X = CH ₃ , H; Y = 0, S

The invention also relates to a process for preparing these compounds. The process for preparing the pure tetrasulfides with a linear S^Ke-te between the two substituted triazine residues is characterized in that an aqueous, alkaline solution of the corresponding N,N'*-substituted 2,4-diamino-6-mercaptotriazines is reacted in a two-phase system with a SiCl solution in an inert organic solvent in which the reaction product is insoluble or very sparingly soluble, at temperatures between -5°C and <+20°C, preferably +10 ^° C. Advantageously, an alkaline aqueous solution of the mercaptotriazine is prepared which contains at least the stoichiometric amount of alkali metal hydroxide required for the reaction, preferably a concentration of 1-20 mol%, based on the mercaptotriazine used.

This solution is treated with a solvent in which the final reaction product is insoluble or sparingly soluble, preferably with Cs-C8 alkanes, Cs- _C8 cycloalkanes, optionally substituted with 1 to 3 methyl groups, and mixtures thereof. This mixture is stirred vigorously and cooled, preferably to -10°C. A solution of _S2Cl2 in the solvent used is then added dropwise to this mixture with thorough cooling. _S2Cl2 is used in a ratio of at least 2 mol/ _mol mercaptotriazine:1 mol _S2Cl2 , but this ratio can also be ₂ :1.1-1.2, depending on the excess alkali. Under the given conditions _{, S2Cl2} acts exclusively as a _condenser .

The resulting product is separated by means of generally known methods and advantageously dried at temperatures up to +50°C under vacuum (10 Torr).

The application also relates to mixtures consisting of compounds of the general formula

^{R3 R4 R3 R4} R ¹ I \l I N |l ^{R1 x X} N

(N), in which R ¹ , R ² , R ³ and R ⁴ have the same meanings as in claim 1 and S _x corresponds to an average statistical chain length with x = 4.

These mixtures, also referred to in the following text as oligosulfurs or disproportionates because they are formed by disproportionation of compounds according to formula I, can be prepared in several ways.

The reaction conditions must be controlled so that no free sulfur is formed.

A process is characterized in that the isolated compound according to formula I is heated above its melting point, preferably by 20-50°C.

In another process, the compounds according to formula I are dissolved in an inert organic solvent and the disproportionation reaction is carried out in the temperature range between 2.0°C (allowing to stand at room temperature) and the boiling point of the solvent used.

A particularly elegant method consists in reacting an aqueous alkaline solution of the corresponding N,N'-substituted 2,4-diamino-6-mercaptotriazines in a two-phase system with a solution of S ₂ Cl ₂ in an inert organic solvent that dissolves the resulting tetrasulfide. The resulting tetrasulfide is then immediately disproportionated into the inventive mixture consisting of oligosulfides.

Chlorinated hydrocarbons, such as CH2Cl2 and CHCl3, are particularly suitable as solvents, but ethers, esters, aromatic hydrocarbons, and ketones are also suitable for the disproportionation reaction. They can be used if they form a two-phase mixture with water. The reaction conditions for preparing the disproportionates are otherwise identical to those for preparing compounds according to formula I.

-4- 270 302

The invention also relates to the use of the claimed compounds in vulcanizable rubber mixtures and to the rubber mixtures themselves containing the compounds according to the invention. The tetrasulfides according to the invention and their disproportionates prove to be significantly superior to the standard compounds used today when used as crosslinkers or vulcanization accelerators. Surprisingly, the N,N'-substituted B1s-(2,4-diaminno-s-triazin-6-yl)-tetrasulfides according to the invention and their disproportionation products prove to be compounds that impart to the rubber mixtures produced therewith extraordinarily high reversion stability even at high vulcanization temperatures—even with very strong overheating—because the reversion process otherwise usual when used with them either does not occur at all or, if it does, only to a small extent. The surprising fact that the crosslinking sites formed by the 1 N,N'-substituted bis-(2,4-diamino-s-triazin-6yl)-tetrasulfides claimed according to the invention or their disproportionates prove to be extremely reversion- and thermostable, leads, when used in rubber mixtures even at high vulcanization temperatures, to the fact that, on the one hand, a high level of performance of the vulcanizes is achieved after completion of the crosslinking reaction and, on the other hand, that the high level of performance is maintained for a long time even in the case of strong overheating.

These two effects taken together enable productivity increases in the rubber processing industry by raising the curing temperature without any loss of vulcanizate performance.

Even approximately the same reversion resistance cannot be achieved with commercially available polysulfides such as Robac® P25 (Robinson, dipentamethylene thiuram tetrasulfide) and Tetron®A (Du Pont, dipentamethylene thiuram hexasulfide) or with dibenzothiazolyl tetrasulfide.

The use of the N,N'-substituted bis-(2,4-diamin-s-triazin-6-yl)-tetrasulfides claimed according to the invention and their disproportionation products includes the rubber mixtures known from the prior art based on natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), isobutylene-isoprene rubber (IIR), ethylene-propylene-toluene polymer (EPDM), nitrile rubber (NBR), halogen-containing rubbers and also epoxidized natural rubbers (ENR) and their blends. The use of the N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)-tetrasulfides claimed according to the invention and their disproportionation products is of particular importance in the case of rubber types susceptible to reversion, such as natural rubber, isoprene and butadiene rubbers, as well as their blends with one another or with other rubbers.

The N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)-tetrasulfides claimed according to the invention and their disproportionation products are used as crosslinking agents in rubber mixtures in an amount of 0.2-15 parts, preferably 0.3-8 parts by weight, per 100 parts of rubber.

In accelerated sulfur vulcanization, the N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)-tetrasulfides claimed according to the invention or their disproportionation products are used as accelerators in amounts of 0.01-10 parts, preferably 0.1-5 parts, based on 100 parts of rubber, with sulfur dosages of 0.1-10 parts. A molar ratio of the accelerators according to the invention to sulfur (S ₈ ) of 1:0.5-1.5 is preferred. In order to achieve a certain range of variation in vulcanization kinetics, it may prove advantageous to use two or more N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)-tetrasulfides or their disproportionates in a mixture, whereby in order to comply with the above-mentioned application quantities, in particular the preferred accelerator/sulfur ratio, the substitution must be carried out on a molar basis. The same applies when using the N,N'-substituted bis-((2,4-diamino-s-triazin-6-yl)-tetrasulfides or their disproportionates as crosslinkers without sulfur.

Also for kinetic reasons, it may prove advantageous to use N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl) tetrasulfides or their disproportionation products in a mixture with conventional accelerators such as sulfenamides and thiurams. These measures occasionally compromise reversion resistance compared to N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl) tetrasulfide vulcanizates; however, partially replacing conventional accelerators with N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl) tetrasulfides or their disproportionates has a conversely positive effect on reversion behavior.

A further significant influence on the incubation time when using the compounds according to the invention in rubber mixtures can be achieved by combination with commercially available vulcanization retarders, such as Santoguard ® PVI (N-(cyclohexylthio)phthalimide), Vulkalent ® E (N-phenyl-N-(trichloromethylsulfenyl)benzenesulfonamide). Vulkalent ^In> E has proven to be the most effective retarder. With increasing Vulkalent ^(RI E) addition, there is a linear increase in the incubation time of N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)-tetrasulfides or mixtures containing their disproportionates.

When using N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl) tetrasulfides or their disproportionation products as crosslinkers, it has proven advantageous to maintain a molar ratio of N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl) tetrasulfides or their disproportionates to Vulkalent E of 1:0.5-1.5, preferably 0.8-1.2 parts per 100 parts of rubber.

Of greater importance is the use of retarders, particularly Vulkalent E, in accelerated sulfur vulcanization using N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl) tetrasulfides and their disproportionates, as well as mixtures thereof. In addition to the intended extension of the incubation time of the crosslinking reaction, a slight impairment of the crosslinking rate, which can be compensated by increasing the temperature, and a slight decrease in reversion resistance are occasionally observed. In this case, it has also been found to be advantageous to adjust the molar ratio of N,N'-substituted bis-(2,4-diamino-s-triazin-6yl)-tetrasulfides or their disproportionates to Vulkalent E to 1:0.5-1.5, preferably 1:0.8-1.2, the sulfur content being kept between 0.1-10 parts per thousand, preferably 0.5-8 parts per thousand, based on 100 parts of rubber, depending on the type of mixture.

-5- 270 302 ·- «

With these dosage guidelines, many of the vulcanization problems posed can be solved without causing a significant loss of vulcanization properties, which contradicts the essence of the invention.

Mixtures containing only silica or carbon black/silica blends with higher silica contents than 15 parts per cubic metre (10 parts per cubic metre) are difficult, if not impossible, to crosslink with conventional sulfur vulcanization systems. On the one hand, they are particularly susceptible to reversal, and on the other hand, they prevent the establishment of the crosslink density required by the finished product specifications. This is one of the reasons why silica is preferred for sole materials and, to date, relatively rarely used in dynamically stressed articles.

Surprisingly, with bis-(2,4-diamino-s-triazin-6-yl)-tetrasulfurs and their disproportionates, it is possible to practically eliminate reversion in mixtures containing black/white blends with silica contents of more than 15 parts per 100 parts of rubber and also with silica-filled mixtures both when used as accelerators and as crosslinkers (without sulfur) and at the same time to increase the pre-wetting density, which is expressed in a stress level that is high for silica mixtures.

A further application of the N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)-tetrasulfides and their disproportionation products is in the combined use with oligosulfidic organosilanes, for example [(HO) ₃ - Si - (OH ₂ ) _n -^2 ^s x ^or (RO) ₃ -Si(OH ₂ ) _{n -^} 3H with x = 2 - 6, R = C _{t -} Cp-Alkyl I, Cyclohexyl n = 2 or 3 respectively

with x = 2-6, preferably 3, preferably bis-(3-triethoxysilylpropyl)-tetrasulfide N,N'-substituted bis-(2,4-diaminno-s-triazin-6-yl)-tetrasulfides and their disproportionates can be used advantageously in sulfur-free organosilane crosslinking instead of the accelerators described in DE-PS 2536674, as well as in the sulfur vulcanization with organosilanes described in DE-PS 22 55 577 and also in the production of reversion-stable organosilane-containing rubber mixtures by building up equilibrium systems according to DE-PS 2848559.

This applies to carbon black-filled mixtures, as well as mixtures containing carbon black/silica blends, and mixtures composed solely of silica. The addition of mineral fillers also has no adverse effects on any of the aforementioned mixtures. In the presence of silica fillers or blends of carbon black with silica, rubber/filler bonds are formed (Kautschuk + Gummi, Kunststoffe, Issue 8, 1977, pp. 516-523, Issue 10, 1979, pp. 760-765, and Issue 4, 1981, pp. 280-284), or in the presence of carbon black, rubber/rubber bonds are formed.

The formation of rubber/rubber cross-links in the presence of carbon black or of rubber/filler cross-links in the presence of silica, as well as both types of bonds in the case of carbon black/silica blends of all ratios, is also possible when N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)-tetrasulfides or their disproportionates are used alone or in a mixture of several or in a mixture with conventional accelerators together with conventional sulfur donors such as sulfasane ^(RI R (morpholine disulfide).

The compound according to the invention is used in rubber mixtures which may contain other conventional components such as:

— common reinforcement systems, i.e. furnace black, channel black, flame black, thermal black, acetylene black, arc black, CK black, etc., as well as synthetic fillers such as silicas, silicates, aluminum oxide hydrates, calcium carbonates and natural fillers such as clays, siliceous chalks, chalks, talcs, etc., as well as silane-modified fillers and their blends in amounts of 5-300 parts per 100 parts of rubber, with particular preference given to silicas and silicates, — ZnO and stearic acid as vulcanization promoters in amounts of 0.5-10 parts of rubber, — commonly used anti-aging, ozone and fatigue agents such as IPPD, TMQ, as well as waxes as light stabilizers and their blends.

— any plasticizers such as aromatic, naphthenic, paraffinic, synthetic plasticizers and their blends, — optionally other silanes such as chloropropyltrialkoxysilanes, vinaltrialkoxysulanes, and aminoalkyltrialkoxysilanes and their blends in an amount of 0.1-15, preferably 1-10 parts per 100 parts of silane-containing fillers such as silicas, silicates, clays, etc.

— if necessary, dyes and processing aids in the usual dosage.

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The field of application of the N,N'-substituted bis-(2,4- ^dimethyl -3-trifluoro-4-yl)-1,2-dimethyl-2-ol tetrasulfides prepared according to the invention extends to rubber compounds as are commonly used in tire construction and to technical articles, such as compounds for conveyor belts, V-belts, molded articles, hoses with and without inserts, roller rubber linings, linings, injection molded profiles, free-hand tires, films, shoe soles and uppers, cables, solid rubber tires and their vulcanizates.

The following products are examples of compounds according to the invention:

A Bia-(2-ethylamlno-4-di-isopropylamlno-s-trlazin-6-yl)-tetraeulfide

B Ris-(2-n-butylamlno-4-diethylamlno-s-trlazin-6-yl)-tetrasulfide

C Bis-(2-isopropylamino-4-di-isopropylamino-s-triazin-6-yl)-tetrasulfide

D B!s-(2-ethylamino-4-di-isobutylamino-8-triazln-6-yl)-tetrasulfide

E '3is-(2-ethylamino-4-di-n-propylamino-s-triazin-6-yl)-tetrasulfide

F Bis-(2-n-propylamino-4-diethylamino-s-triazin-6-yl)-tetrasulfide

G Bis-(2-n-propylamino-4-di-n-propylamino-s-triazin-6-yl)-tetrasulfide

H 8is-(2-n-butylamlno-4-di-n-propylamino-s-triazin-6-yl)-tetrasulfide

I '?·!£ '2-ethylamino-4-di-n-butylamino-s-triazin-6-yl)-tetrasulfide

K 3iM?.-isopropylamino-4-di-isp'Opylamino-s-triazin-6-yl)-oligosulfide mixture

L Bis-(2-cyclohexylamino-4-dieuiylamino-s-triazin-6-yl) oligosulfide mixture

M Bis-(2-ethylamino-4-diethylamino-s-triazin-6-yl) oligosulfide mixture

Bis-(2-amino-4-diethylamino-s-triazine-6-y!l-oligosulfide mixture

Examples of implementation

The invention is explained in more detail below using some examples.

Example 1:

454 g of 2-ethylamino-4-diathylamino-6-mercaptotriazine are dissolved in sodium hydroxide solution prepared from 84 g NaOH + 1.5 liters of H _a O.

The solution is placed in a 4 liter 3-tube flask, then 1.5 liters of light petrol (bp 80-110°C) are added and the mixture is cooled to 0°C while stirring vigorously.

Now, within 20 minutes, a solution of 137 g of S ₂ CI ₂ in 100 ml of petrol is allowed to run in, taking care that the temperature does not exceed +5'C.

The tetrasulfide precipitates immediately. At the end of the reaction, the mixture is stirred for 5 ml, then filtered with suction and washed.

The snow-white fine powder is dried in vacuum/12 Torr at 40-45’C.

Quantity: 499.5g, corresponding to 97.1% of theory F. 149-150°C.

Analysis:

Bis-(2-ethylamino-4-diethylamino-s-triazin-6-yl)-tetrasulfide,

Molecular weight 516, CteH3 ₂ NtoS ₄ calc. C41.9 H6.2 N27.1 S24.8 found. C41.8 H6.5 N26.8 S24.8

TLC and HPLC analysis show that the product contains 97.1% linear tetrasulfide.

Example 2:

Dissolve 56.6 g of 2-ethylamino-4-dl-n-butylamino-6-mercaptotriazine in a solution of 8.8 g NaOH in 250 ml water. Add 250 ml of gasoline. Stir thoroughly and cool the mixture to +5°C. A solution of 13.5 g of S ₂ Cl ₂ in 30 ml of gasoline is then added. A white precipitate forms immediately. At the end of the reaction, work up as per Example 1. Amount: 56 g, corresponding to 89.2% of theory.

Analysis: C _2e H«NioS4 (molecular weight 628) calc. C 49.68 H7.64 N 22.29 S 20.38 found. 049.59 H7.59 N 22.18 S20.40

HPLC analysis: Purity > 96%.

Example 3:

107.6 g of 2-i-propylamino-4-diisopropylamino-6-mercaptotriazine is dissolved in sodium hydroxide solution, which is prepared from 17.6 g of NaCH in 600 ml of H ₂ O. 600 ml of methylene chloride is added.

At 0-5°C, a solution of 27g of S ₂ Cl ₂ in 50ml of CH ₂ Cl ₂ is added. At the end of the reaction, the organic phase is separated in a separatory funnel, dried, and evaporated in vacuo. An amorphous powder is obtained; softening point: 90°C.

Yield: 112.5g, corresponding to 94% of theory.

Analysis: C^H^NwS« (molecular weight 600)

-7- 270 302 calc. C48 H 7.33 N23.3 S21.3 found. C48.2 H7.36 N 23.01 S 20.95

Example 4:

Dissolve 45.4 g of 2-ethylamino-4-diethylamino-6-mercaptotriazine in sodium hydroxide solution, prepared from 8.8 g of NaOH and 200 ml of water. Add 200 ml of methylene chloride. The mixture is turbined and cooled to 0°C. Dissolve 14 g of S ₂ Cl ₂ in 50 ml of CH 2 Cl 2 and allow this solution to run into the mercaptochloride solution.

The reaction product dissolves in CH ₂ Cl ₂ . At the end of the reaction, the phases are separated, and the CH _; Cl _; solution is processed. This yields an amorphous powder with a softening point of approximately 110°C.

Quantity: 46.7g, corresponding to 90.5% of theory.

Analysis: C _lg H ₂₂ NioS ₄ (mol wt. 516) calc. N27.1 S24.8 found N26.8 S24.4

According to TLC analysis, a mixture of 4 oligosulfides was found, but no free sulfur.

Example 5:

50 g of bis(2-ethylamino-4-diethylamino-$-triazin-6-yl) tetrasulfide with a purity of 97.1% is placed in a round-bottom flask and heated in an oil bath at 160°C for 1 hour. Upon cooling, the melt solidifies amorphously. According to TLC analysis, the product contains approximately 50% of the starting material and three other oligosulfides.

Example 6:

Dissolve 70.25 g of 2-cyclohexaylamino-4-diethylamino-6-mercaptotriazine in 11 g of NaOH and 250 ml of water. Add 250 ml of chloroform. A solution of 16.8 g of S ₂ Cl ₂ in 30 ml of CHCl ₃ is added with vigorous stirring. At the end of the reaction, the phases are separated, and the chloroform layer is purified. 71.9 g of a white amorphous powder is obtained, corresponding to 92% of theory.

Analysis: ChH^N^S« (mol wt. 624) calcd. C50 H7.05 N22.4 S 20.51 found C49.1 H6.90 N21.8 S20

According to TLC analysis, the product consists of approximately 30% linear S ₄ product and 70% oligosulfides, but contains no free sulfur.

Examination standards

The physical tests were carried out at room temperature according to the following standard specifications:

measured in

Tensile strength, elongation at break, and stress value on 6mm thick DIN 53504 MPa Shore A hardness DIN 53 505 Firestone Ball Rebound AD 20245 % Reversion DE-PS2848 559 Incubation period; DIN 53 529 (min) Scorch time ASTMD 2084 (min)

The following names and abbreviations are used in the application examples, the meaning of which is given below.

RSS: Ribbed Smoked Sheet (natural rubber) carbon black, surface area (BET) 120 m ² /g (Degussa)

CORAX® N 220:

Naftolen®ZD: Hydrocarbon plasticizers Ingraplast® NS: Vulkanox®3010NA: Vulkanox®HS: Mesamoll®: Plasticizers made from naphthenic hydrocarbons: N-isopropyl-N'-phenyl-p-phenylenediamine, poly-2,2,4-trimethyl-1,2-dihydroquinoline, alkylsulfonic acid esters of phenol and cresol RobacF25 TetroneA protector* G 35: Dipentamethylenethiuram tetrasulfide Dipentamethylenethiuram hexasulfide Ozone protection wax Vulkacit*MOZ: Vulkacit® Mercapto: Vulkacit®Thiuram: Benzthiazolyl-2-morpholino-sulfenamide 2-mercaptobenzothiazole tetramethyl-thiuram monosulfide Vulkacit® CZ: Vulkalent® E: N-Cyxclohexyl-2-benzothiazolesulfenamide N-Phenyl-N-(trichloromethylsulfenyl)-benzenesulfonamide

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PVI: Ultrasil®VN3: Gran. V143: Vulcacite*NZ: N-Cyclohexylthiophthalamide precipitated silica (Degussa) granules Bis-(2-ethylamino-4-diethylamino-8-[(triazin-e-yl)-disulfide) Benzothiazyl-2-tert.-butyl-sulfenamide

Example 7i

Reversion stability of N 220-filled NR crosslinked with N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)-tetrasulfides (without sulfur)

RSS 1,ML4 = 70-80 100 CORAX N 220 50 ZnORS 5 Stearic acid 2 NaftoleneZD 3 Vulkanox4010NA 2.5 VulkanoxHS 1.5 Protector G 35 1 VulkacitMOZ 1.43 V143 — Santoguard PVI — B — D — Sulfur 1.5 Reversion:

^D max ^(max+öO ¹ )

D -D . 30.1 max min

2 3 4 100 100 100 50 50 50 5 5 5 2 2 2 3 3 3 2.5 2.5 2.5 1.5 1.5 1.5 1 1 1 — — — 1.29 — — 0.4 — __ — 3.34 — — — 4.10 1.5 8.6 2.3 2.1

at 170°C

Vulcanization temperature

RSS 1,ML4 = 70-80 CORAX N 220 ZnORS

Stearic acid

NaftolenZD Vulkanox4010NA VulkanoxHS Protector G 35

K

L

M

Reversion:

&max ^(max+öO')

100

2.5

1.5

3.84

100

2.5

1.5

3.62

100

2.5

1.5

4.0 max min (%) ,5 3.1

2.3 at 170°C

Vulcanization temperature

The N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)-oligosulfides according to the invention, when used as crosslinkers (without sulfur), prove to be extremely reversion-stable in carbon black-filled NR mixtures (mixtures 3-7) compared to a somi-EV system (mixture 1) or to a mixture containing bis-(2-ethylamine-4-diethylamine-s-triazin-6-yl)-disulfide (V143) (mixture 2).

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Example 8;

Reversion stability of N220-sclerosing acid-filled NR (without sulfur) cross-linked with N,N’-substituted bis-(2,4-diamino-8-triazine-6-yl)-tetrasulfides

8 9 10 11 12 RSS 1, ML (1+4) = 70-80 100 100 100 100 100 CORAX N 220 25 25 25 25 25 Ultra8ilVN3Gran. 25 25 25 25 25 ZnORS 5 5 5 5 5 Stearic acid 2 2 2 2 2 NaftoleneZD 3 3 3 3 3 Vulkanox 401 ONA 2.5 2.5 2.5 2.5 2.5 Vulkanox HS 1.5 1.5 1.5 1.5 1.5 ProtectorG35 1 1 1 1 1 VulcanoMoz 1.43 — — — — C — 3.48 — — — E — — 3.46 — — G — — — 3.62 — 1 — — — 3.78 Sulfur 1.5 — — — —

Reversion:

D - 0 , , “ , v max_____(max+60 ¹ )

- D .

max min (X) 47.1

1.8 2.4

3.3 6.2 at 170°C

Vulcanization temperature

13 14 15 RSS1,ML(1 + 4) = 70-80 100 100 100 CORAX N 220 25 25 25 UltrasilVN3Gran. 25 25 25 ZnORS 5 5 5 Stearic acid 2 2 2 NaftoleneZD 3 3 3 Vulkanox 401 ONA 2.5 2.5 2.5 Vulkanox HS 1.5 1.5 1.5 ProtectorG35 1 1 1 K 3.48 — — L — 3.62 — M Reversion: 3.0 Dfnax ^(max+60') - ^(%) 25 3.1 4.7 D - D . max mw

at 170°C

Volcanization temperature

Silica-containing NR mixtures exhibit particularly strong reversion phenomena, even when used with semi-EV systems (mixture 8). With the N,N'-substituted bis-(2,4-diamino-s-triazine-6α-tetra- or -oligosulfides used according to the invention as crosslinkers (mixtures 9-15), a virtually reversion-free state is achieved with otherwise identical mixture composition.

-10- 270 302

Example 8.

Reversal resistance of N 220 filled NR accelerated with N,N'-substituted Bls-(2,4-dlamlno-s-trlazln-6-yl)-tetrasulfides

16 17 18 19 20 RSS 1, MUI +4) = 70-80 100 100 100 100 100 CORAX N 220 50 50 50 50 50 ZnORS 5 5 5 5 5 Stearic acid 2 2 2 2 2 NaftoleneZD 3 3 3 3 3 Vulkanox4010NA 2.5 2.5 2.5 2.5 2.5 VulkanoxHS 1.5 1.5 1.5 1.5 1.5 ProtectorG35 1 1 1 1 1 Vulkacite MOZ 1.43 — — — — B — 1.66 — — — C — — 1.74 — — D — — — 1.76 — E — — — — 1..73 Sulfur 1.5 0.8 0.8 0.8 0.8 Reversion: D-D, max (max+60*) (Z) D-D. 31.9 0.4 0.0 0.0 1.3 max min at 170°C Vulcanization temperature Volcano satellite data at 170 ^° C, t95% Tensile strength 23.0 22.6 24.1 21.3 20.8 Voltage value 300% 9.6 10.9 10.9 10.5 9.1

Continuation (1)

Example 9:

Reversal resistance of N,N'-substituted bis-(2,4-dlamino-s-triazin-6-yl)-tetrasulfides accelerated by N 220-filled NR

21 22 23 24 RSS 1, ML (1+4) = 70-80 100 100 100 100 CORAX N 220 50 50 50 50 ZnORS 5 5 5 5 Stearic acid 2 2 2 2 NaftoleneZD 3 3 3 3 Vulkanox4010NA 2.5 2.5 2.5 2.5 VulkanoxHS 1.5 1.5 1.5 1.5 ProtectorG35 1 1 1 1 F 1.65 — — — G — 1.81 — — H — — 1.82 — I — — — 1.82 Sulfur reversion: 0.8 0.8 0.8 0.8 %ax ^(max+60 ¹ ) (7.) 1.3 2.0 1.2 2.1 D - D . max min at 170°C Vulcanization temperature Vulcanizate data at 170°C, 95% tensile strength 19.9 22.1 22.0 23.2 Voltage value 300% 10.4 10.8 11.9 10.5

-11- 270 302

Example 9:

Reversal resistance of N 220 filled NR accelerated with N,N'-substituted Bls-(2,4-diamlno-s-triazine-6-yl)-oligosulfides

26 28 27 RSS 1, (ML 1+4) = 70-80 100 100 100 CORAX N 220 60 60 60 ZnORS 5 6 6 Stearic acid 2 2 2 NaftoleneZD 3 3 3 Vulkanox4010NA 2.5 2.5 2.5 VulkanoxHS 1.5 1.5 1.5 ProtectorG35 1 1 1 K 1.74 — — L — 1.81 — M — — 1.5 Sulfur reversion: 0.8 0.8 0.8 ^D mux D(max+60') 0.4 1.5 5.2 D-D max min 170°C Vulcanization temperature Vulcanizate data at 170°C, 95% tensile strength 22.9 24.2 22.2 Voltage value 300% 10.3 10.0 10.6

With equimolar accelerator dosage, the amount of sulfur can be reduced in the case of N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)tetra- or oligosulfides. Nevertheless, higher 300% strain values are achieved. The mixtures prepared with N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)tetra- or oligosulfides (mixtures 17-27) prove to be extremely reversion-resistant against a semi-EV system (mixture 16).

Example 10:

Efficacy comparison of sulfonamide with N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)-tetrasulfide acceleration in N 220-filled NR at the same S _e dosage

RSS1 ML (1+4) = 70-80100

CORAX N 22050

ZnORS5

Stearic acid2

NaftolenZD3

ProtectorG351

Vulkanox4010NA2.5

VulkanoxHS1.5

Vulkacite MOZ 1.43

D—

Sulfur1.5

Reversion:

max (max.x+60 ¹ )

D “031.9 maximum)

100

S

2.6

1.5

1.76

1.5

5.1

12.8 at 170°C

Vulcanization temperature Vulcanizate data at 160°C, t95% stress value 300%, MPa 10.6

Shore A hardness 63

Example 9 showed the comparison of MOZ with N,N'-substituted bis(2,4-diamino-s-triazin-6-yl)tetrasulfides or their disproportionation products at different sulfur concentrations. However, if the sulfur concentration is kept constant at an equimolar amount of accelerator, the reversal ion difference remains, but the potential value 3G0% increases considerably.

-12- 270 302

Example 11: Comparison of the reversibility behavior of commercially available oligosulfides and dibenzthlazolyl tetrasulfide versus N,N'substituted bis-(2,4-dlamino-a-triazin-6-yl)-oligosulfide in N 220-filled NR.

30 31 32 33 RSS 1, ML (1+4)=70-80 100 100 100 100 CORAX N 220 50 50 50 50 ZnORS 5 5 5 5 Stearic acid 2 2 2 2 NaftoleneZD 3 3 3 3 Vulkanox4010NA 2.5 2.5 2.5 2.5 VulkanoxHS 1.5 1.5 1.5 1.5 ProtectorG35 1 1 1 1 RobacP25 1.12 — — — Tetrone A — 1.3 — — Dibenzothiazolyl tetrasulfide — — 1.15 — M — — — 1.5 Sulfur 0.8 0.8 0.8 0.8 Scorching time170 ^o C 1.4 1.9 2.7 3.1 (t10%), min Reversion:

^D max ^D (max+60')

D - D . max min 18.5 21.3 35.7 3.2 at 170°C Vulcanization temperature Vulcanizate data at 170°C, t 95% Tensile strength 23.1 21.2 18.9 23.6 Voltage value 300% 9.4 9.5 7.3 10.4

Commercially available oligosulfides (mixtures 30 and 31) as well as dibenzothiazolyl tetrasulfide (mixture 32) show several times higher reversion in NR than a Ν,Ν'-substituted bis-(2,4-diamino-s-triazine-6-yl-)-oligosulfide (mixture 33).

Example 12: Blend of N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl-)-tetrasulfide with sulfur donor in N 220-filled NR

RSS 1 ML (1+4) = 70-80 CORAX N 220 ZnORS Stearic acid NaftolenZD ProtectorG35 Vulkanox4010NA VulkanoxHS Vulkacit MOZ Sulfasan R

D Sulfur reversion: %ax ^(max+60*)

34 35 100 100 50 50 5 5 2 2 3 3 1 1 2.5 2.5 1.5 1.5 1.43 — — 0.7 — 1.76 1.5 (X) 30.6 2.1

max min at 170°C

Vulcanization temperature

Compared to conventional sulfenamide acceleration (mixture 34), the use of N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)tetrasulfide with Sulfasan R as sulfur donor (mixture 35) results in a clear reversion improvement.

-13- 270 302

Example 13: Blend of commercially available accelerators with N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)-tetrasulfide in N 220-filled NR

36 37 38 39 40 RSS 1, ML (1+4) = 70-80 100 100 100 100 100 CORAX N 220 50 50 50 50 50 ZnORS 5 5 5 5 5 Stearic acid 2 2 2 2 2 NaftoleneZD 3 3 3 3 3 Vulkanox 401 ONA 2.5 2.5 2.5 2.5 2.5 VulkanoxHS 1.5 1 fi 1.5 1.5 1.5 Protector 1 1 1 1 1 Vulkacite MOZ 1.43 0.71 1.5 — — Vulkacite DM — — — 1.56 0.78 B — 0.8 1.58 — 0.8 Sulfur 1.5 1.5 — 1.5 1.5 ^D max ^D (max+60') (X) 0-0. 28.7 16.8 5.7 31.2 16.1 max min

bel170 ^e C Vulcanization temperature Vulcanizate data at 170°C Tensile strength 300%, 195% 11.3 11.9 6.8 9.0 11.4 t95% + 90* 8.9 10.7 6.7 7.5 10.5

41 42 43 44 RSS 1, (ML 1+4) = 70-80 100 100 100 100 CORAX N 220 50 50 50 50 ZnORS 5 5 5 5 Stearic acid 2 2 2 2 NaphtoienZD 3 3 3 3 Vulkanox 4010 NA 2.5 2.5 2.5 2.5 Vulkanox HS 1.5 1.5 1.5 1.5 Protector G 35 1 1 1 1 Vulkacite DM 1.56 — — — Vulkacite Merkapto — 1.2 0.6 1.2 B 1.58 — 0.8 1.58 Sulfur — 1.5 1.5 - ^max ^D (max+60') D - D max min (X) 4.1 28.7 14.9 4.5

at 170°C vulcanization temperature Vulcanizate data at 170°C modulus 300% 195% 7.0 7.8 11.3 t95% + 80’ 6.9 6.5 10.8

5.9

5.9

The combination of commercially available accelerators with N,N'-substituted bis(2,4-diamino-s-triazin-6-yl)tetrasulfides (mixtures 37, 40, 41) leads to a clear improvement in reversion behavior compared to the use of the commercially available accelerators alone (mixtures 36, 39, 42). A further increase in reversion resistance can be achieved by eliminating the sulfur (mixtures 38, 41, 44).

Example 14: Blend of N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)-tetrasulfide with N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)-oligosulfide in N 220-filled NR.

45 46 47 48 RSS 1, ML (1+4) = 70-80 100 100 100 100 CORAX N 220 50 50 50 50 ZnORS 5 5 5 5 Stearic acid 2 2 2 2 NaftoleneZD 3 3 3 3 Vulkanox 4010 NA 2.5 2.5 2.5 2.5 VulkanoxHS 1.5 1.5 1.5 1.5

-14- 270 302

45 46 47 48 ProtectorG35 1 1 1 1 VulkacitMOZ 1.43 — — — M 1.5 — 0.75 B — — 1.66 0.83 Sulfur 1.5 0.8 0.8 0.8 ^D max ^Cmax+öO ¹ ) (%) 2.3 0.4 1.2 30.1

D-D .

max min bell 70 *C

Vulcanization temperature

The combined use of N,N'-substituted Bls-(2,4-diamino-s-triazol-e-yl)-tetrasulfides with different reversion resistance results in a value profile that lies between the pure substances (mixture 48).

Example 15: Reversion during acceleration with B in NR with carbon black/silica blend.

49 50 RSS1 ML (1+4) = 70-80 100 100 CORAX N 220 25 25 UltrasilVN3Gran. 25 25 ZnORS 5 5 Stearic acid 2 2 Naftolene 3 3 ProtectorG35 1 1 Vulkanox4010NA 2.5 2.5 VulkanoxHS 1.5 1.5 VulkacitMOZ 1.43 — B — 1.67 Sulfur 1.5 0.8 max ^D (max+60') (%) 10.8 46.7 0 - D . max min at 170°C

Vulcanization temperature f When the sulfenamide accelerator (mixture 49) is replaced by N,N'-substituted bis-(2,4-diamlno-s-trilazin-6-yl)tetrasulfide (mixture 50), the reversion drops drastically.

Example 16: N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)-tetra- and -oligosulfides in N 220-filled SBR

51 52 53 54 55 SBR 1500 100 100 100 100 100 CORAX N 220 50 50 50 50 50 ZnORS 5 5 5 5 5 Stearic acid 2 2 2 2 2 Naftolen ZD 3 3 3 3 3 ProtectorG35 1 1 1 1 1 Vulkanox4010NA 2.5 2.5 2.5 2.5 2.5 VulkanoxHS 1.5 1.5 1.5 1.5 1.5 ProtectorG35 1 1 1 1 1 VulkacitMOZ 1.43 — — — — B — 1.66 — — — F — — 1.58 — — K — — — 1.5 — M — — — — 1.5 Sulfur 1.5 1.5 1.5 1.5 1.5 max ^Cmax+öO') (%) 0 - D . 12.9 11.3 11.5 9.2 12.5

max min b8i170°C

Vulcanization temperature

-15- 270 302

51 52 53 54 55 Vulcanization date in 170°C, t95% Tensile strength 20.6 21.3 20.8 20.5 19.9 Voltage value 300% 10.0 11.6 12.2 12.1 12.3 Elongation at break 460 440 420 420 390 Shore hardness 61 63 63 63 64

At the same sulfur dosage, N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl-)-tetra- and -oligosulfides (mixture 52-55) in SBR1600 show a significantly higher stress value and slightly improved reversion properties against a conventional acceleration (mixture 51).

Example 17: N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl-)-tetra- or -oligosulfides in N 220-filled isoprene rubber

56 57 58 59 Polyisoprene 3,4 100 100 100 100 CORAX N 220 50 50 50 50 ZnORS 5 5 5 5 Stearic acid 2 2 2 2 NaftoleneZD 3 3 3 3 Vulkanox4010NA 2.5 2.5 2.5 2.5 VulkanoxHS 1.5 1.5 1.5 1.5 ProtectoO35 1 1 1 1 VulkacitMOZ 1.43 — — — B — 1.76 — — L — — 1.6 — M — — — 1.5 Sulfur 1.5 0.8 0.8 0.8 Reversion: ^D max ^Cmax+öO ¹ ) (7.) 21.0 2.1 0.0 0.0 0 - D . max mm at 170°C Vulcanization temperature Vulcanizate data at 170°C Voltage value 300% 195% 7.9 6.6 6.3 6.4 95% + 80' 6.2 6.8 6.3 7.1

In polyisoprene rubber, the use of N,N'-substituted bis-(2,4-d;amino-s-triazin-6-yl)tetra- or oligosulfides (compounds 57-59) compared to conventional accelerators (compound 56) also results in a significant improvement in reversion. This improvement is also reflected in the consistency of the vulcanizate data under significant overheating.

Example 18: N,N'-substituted bis-(2,4-diaminotriazin-6-yl)-tetra- and -oligosulfides in N 220-filled EPDM

60 61 62 BunaAP451 100 100 100 CORAX N 220 50 50 50 ZnORS 5 5 5 Stearic acid 2 2 2 Ingraplast NS 10 10 10 Volcanite Thiuram 1 — — Vulkacite Mercapto 0.5 — — B — 2.93 — M — — 2.5 Sulfur 1 1 1 ^D max ^D (max+60') ' (X) 3.3 0.0 0.0

D - D . max mm at 160°C

Vulcanization temperature

EPDM mixtures already highly reversion-resistant show a further reduction of the reversion to zero when conventional accelerator mixtures (mixture 60) are replaced by N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)tetra- or •oligosulfides (mixtures 61 and 62).

-16- 270302

Example 19: N,N'-substituted bis-(2,4-diamino-s-triazol-6-yl)-tetra and -olgosulfides in N 220-filled NBR

63 64 65 Perbunan N 3307 NS 100 100 100 CORAX N 220 60 60 60 ZnORS 5 5 5 Stearic acid 1 1 1 Paraffin solid 1 1 1 Mesamoll 10 10 10 VulkanoxHS 1.5 1.5 1.5 Vulkacite CZ 1.5 1.5 1.5 D — 1.76 — M — — 1.5 Sulfur 1.2 1.2 1.2 Reversion: D|nax ^(max+60') ' (X) 8.0 5.4 5.6 D-D. max min at 170°C Vulcanization temperature Vulcanizate data at 170°C, t95% Voltage value 300% 11.8 14.0 14.6 Shore hardness 68 69 69

At the same sulfur content, when compared to the reference mixture (mixture 63), when replaced by N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)-tetra- or oligosulfides (mixtures 64 and 65) in NBR, a strong increase in the stress value at 300% elongation occurs with a simultaneous reduction in the reversion.

Example 20: Reversion stability I of Ι,Ν'-substituted bis-(2,4-diamino-s-triazin-6-yl)-oligosulfides in N 220-filled BR

66 67 68 Buna CB 10 100 100 100 CORAX N 220 60 60 60 ZnORS 3 3 3 Stearic acid 2 2 2 NaftoleneZD 15 15 15 ProtectorG35 1 1 1 Vulkanox4010NA 1.5 1.5 1.5 Volcanite NZ 1.5 — — M — 1.5 — D — — 1.76 Sulfur 1.5 1.5 1.5

Reversion “0/ .znix max (max+60')

D - 0 .

max min at 170°C

Vulcanization temperature Vulcanizate data at 170°C

Stress value 300 %t 95% t95 + 75'

30.3 20.8 19.1 8.6 8.9 8.2 5.6 6.8 6.6

Due to the lower reversion of the M and D accelerated BR mixtures (mixtures 67 and 68), the drop in the voltage value of 300% at strong overheating is significantly reduced compared to the reference mixture (mixture 66).

Example 21: N,N'-substituted bis-(2,4-diari'.:.~5-s-triazin-6-yl-)-tetra- and -oligosulfides in N 220-filled NR-BR/blend

-17- 270 302

69 70 71 72 RSS1,ML(1+4) = 70-80 70 70 70 70 Buna CB 10 30 30 30 30 CORAX N 220 50 50 50 50 ZnORS 5 5 6 5 Stearic acid 2 2 2 2 NaftoleneZD 3 3 3 3 Vulkanox4010NA 2.5 2.5 2.5 2.5 VulkanoxHS 1.5 1.5 1.5 1.5 ProtectorG35 1 1 1 1 VulkacitMOZ 1.43 — — — C — 1.74 — — D — — 1.76 — M — — — 1.5 Sulfur 1.5 0.8 0.8 0.8 Reversion: %ax D(max+60') (%) 32.0 15.8 20.6 23.8

D-D .

max min bel170*C

Vulcanization temperature

Blends 70 to 72 show a significant reduction in reversion when using N,N'-substituted bis-(2,4-diaminos-triazin-6-yl)-tetra and oligosulfides against a semi-EV system (blend 69) in a blend of NR and polybutadiene.

Example 22: Crosslinking of 50% epoxy-coated natural rubber (ENR 50) with N 220 filling with N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)tetra- or oligosulfide

73 74 75 ENR 50 100 100 100 CORAX N 220 50 50 50 ZnORS 5 5 5 Stearic acid 2 2 2 VulkanoxHS 2 2 2 VulkacitMOZ 2.4 — Volcanite Thiuram 1.6 — — C — 4.6 — M — — 4.0 Sulfur reversion: 0.3 0.3 0.3 ^D max ^Cmax+öO') (%) 0.0 0.0 6.7 D - D . max m1n at 150°C Vulcanization temperature Vulcanization data at 150°C, 95% tensile strength 18.7 23.9 24.6 Voltage value 300% 18.0 18.4 18.9 Tear resistance 12 14 12 Shore hardness 75 76 78

At the same stress value at 300% elongation and considerably increased tensile strength, the replacement of a conventional accelerator (mixture 73) by N,N'-substituted bis-(2,4-diamino-s-triazine-6-yl)-tetra- or oligosulfides (mixtures 74 and 75) leads to an additional improvement in reversibility.

Example 23: Effect of Vulkalent E on sulfur-free NR crosslinking of N 220 and N 220/silica-filled NR with N,N'-substituted bis-(2,4-diamino-s-triazine-6-yl)-tetrasulfide

-18- 270 302

76 77 78 79 80 81 _t RSS 1,ML(1+4) = 70-80 100 100 100 100 100 100 CORAX N 220 50 50 50 25 25 25 UitrasilVN3Gran. — — — 25 25 25 ZnORS 5 5 5 5 5 5 Stearic acid 2 2 2 2 2 2 NaftoleneZD 3 3 3 3 3 3 Vulkanox4010NA 2.5 2.5 2.5 2.5 2.5 2.5 VulkanoxHS 1.5 1.5 1.5 1.5 1.5 1.5 Protector G 35 1 1 1 1 A 1 1 VulkacitMOZ 1.43 — — 1.43 — — C — 3.79 3.79 — 2.84 2.84 Vulkalent E — — 3.2 — — 2.4 Sulfur 1.5 — — 1.5 — — Reversion:

^D max ^Cmax+öO') _f “ ' k Λ

D - D . max min 32.5 4.1 4.5 47.8 5.4 5.5 at 170°C Vulcanization temperature ti170’C,(min) 4.2 2.8 4.6 4.7 3.0 4.7

In N 220 and N 220/silica filled and C cross-linked NR, the addition of Vulkalent E achieves the desired extension of the incubation time without impairing the reversion.

Example 24: Retarding effect of Vulkalent E on N,N'-substituted bis-(2,4-diamino-triazin-6-yl-)tetra- and oligosulfide vulcanized N 220/NR compounds

82 83 84 85 86 RSS1,ML4 = 70 —80 100 100 100 100 100 CORAX N 220 50 50 50 50 50 ZnORS 5 5 5 5 5 Stearic acid 2 2 2 2 2 NaftoleneZD 3 3 3 3 3 Vulkanox4010NA 2.5 2.5 2.5 2.5 2.5 VulkanoxHS 1.5 1.5 1.5 1.5 1.5 Protector G 35 1 1 1 1 1 VulkacitMOZ 1.43 — — — — B — 1.66 1.66 — — M — — — 1.55 1.55 Schwe'il 1.5 0.8 0.8 0.8 0.8 Vulkalent E — — 1.2 — 1.2 Ti (min 3.8 3.0 4.4 :’,9 4.1 at 170°C Vulcanizate data at 170°C, t95% Voltage value 300% 10.6 10.2 11.5 10.6 11.0

The addition of Vulkalent E in B and M accelerated mixtures (mixtures 84 and 86) leads to an increase in the incubation time ti above the level of the conventionally MOZ accelerated mixture (mixture 82).

Example 25: N,N'substituted bis-(2,4-diamino-s-triazin-6-yl-)-tetrasulfides with Vulkalent-E additive in N 220-filled NR in

Temperature dependence 87 88 89 RSS1M! (1+4) = 70-80 100 100 100 CORAX N 220 50 50 50 ZnORS 5 5 5 Stearic acid 2 2 2 Naftolen ZD 3 3 3 Protector G 35 1 1 1 Vulkanox4010NA 2.5 2.5 2.5 VulkanoxHS 1.5 1.5 1.5 VulkacitMOZ 1.43 — — B — 1.66 1.66 Vulkalent E — — 1.2

-19- 270 302

,_*1Ώ

Sulphur ^D max (Cmax+öO')

D - 0 .

max mm at 145°C, test temperature at 160°C test temperature at 170°C test temperature at 180°C test temperature

1.5 0.8 0.8 7.9 0.0 0.0 26.6 0.0 1.9 30.9 0.4 3.6 39.1 2.6 5.6

Example 25 shows a pronounced temperature sensitivity of the reversion in pure N,N'-substituted bis-(2,4-diamino-e-triazin-8-yl)-tetrasulfide acceleration (Mixture 88) as well as in the case of the addition of Vulkalent E (Mixture 89) compared to conventional acceleration (Mixture 87).

Example 26: Effect of Vulkalent E on N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl-)-tetrasulfide and oligosulfide cross-linked NR with N 220/silica

90 91 92 93 94 RSS1,ML (1+4) = 70-80 100 100 100 100 100 Ultrasil VN 3 Grams. 25 25 25 25 25 CORAX N 220 25 25 25 25 25 ZnORS 5 5 5 5 5 Stearic acid 2 2 2 2 2 NaftoleneZD 3 3 3 3 3 Vulkanox4010NA 2.5 2.5 2.5 2.5 2.5 VulkanoxHS 1.5 1.5 1.5 1.5 1.5 Protector G 35 1 1 1 1 1 Vulkacite MOZ 1.43 — — — — D — 3.5 3.5 — — M — — — 3.0 3.0 Vulkalent E — — 1.2 — 1.2 Sulfur 1.5 0.8 0.8 0.8 0.8 Scorch at 130 °C (min) 29.5 15.0 28.5 16.5 29.0 Scorch at 170°C (ml) 4.5 3.4 4.4 3.7 4.8

With Vulkalent E, a scorching behavior comparable to MOZ can be achieved when accelerated with N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)-tetra- or oligosulfides (mixtures 92 and 94).

Example 27: Simultaneous use of N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl-)-tetrasulfide and Si 69 with or without Vulkalent E in N 220/VN 3-filled NH

95 96 97 98 99 RSS1,ML(1 + 4) = 70-80 100 100 100 100 100 CORAX N 220 25 '25 25 25 25 Ultrasil VN 3 Grams. 25 25 25 25 25 SI69 3.75 3.75 3.75 3.75 3.75 ZnORS 5 5 5 5 5 Stearic acid 2 2 2 2 2 NaftoleneZD 3 3 3 3 3 Vulkanox4010NA 2.5 2.5 2.5 2.5 2.5 VulkanoxHS 1.5 1.5 1.5 1.5 1.5 ProtectorG35 1 1 1 1 1 Vulkacite MOZ 1.43 — — — — B — 2.2 2.2 1.66 1.66 Vulkalent E — — 1.6 — 1.2 Sulfur 1.5 — — 0.8 0.8 Reversion: ^D max ^D (max+60') (%) 0-0. 19.6 0.0 0.0 0.0 0.0 max min at UO’C Vulcanization temperature ti at 170°C (min) 4.6 4.2 5.7 4.2 5.2

When N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl-)-tetrasulfides and Si 69 are used together,

-20- 270 302 reversion-free mixtures, both with and without sulfur (mixtures 96 and 98), were obtained compared to conventional accelerators with silane (mixture 95). The addition of Vulkalent E also leads to an extension of the scorch time in this case without the recurrence of reversion (mixtures 97 and 99).

Example 28:

Crosslinking of N 220/silica-filled NR with N,N'-substituted bis-(2,4-diamino-triazin-6-yl)-tetrasulfide without sulfur

RSS1

CORAX N 220 Ultra VN 3 Grams

ZnORS Stearic acid NaftolenZD Vulkanox 401 ONA Vulkanox HS

ProtectorG35 VulkacitMOZ

D

Sulfur ^D max ^D (max+60') “ ——————

-D .

max min at 170°C vulcanization temperature vulcanizate data (t95%)bel170’C stress value 300%

100 100 100 25 25 25 25 25 25 5 5 5 2 2 2 3 3 3 2.5 2.5 2.5 1.5 1.5 1.5 1 1 1 1.43 — — — 2 3 1.5 — — 44.7 3.2 2.0 4.9 2.6 4.4

100 100 100 25 25 25 25 25 25 5 5 5 2 2 2 3 3 3 2.5 2.5 2.5 1.5 1.5 1,” 1 1 1 — — — 4 5 6 — — — 1.3 3.1 2.8 5.8 6.8 7.8

100

2.5

1.5

2.6

Sulfur-free crosslinking with N,N'-substituted bis-(2,4-diamino-triazin-6-yl)-tetrasulfide in natural rubber with carbon black and silica filling leads to a suppression of reversion and at the same time to a quantity-dependent increase in the stress value.

Example 29:

Crosslinking of silica-filled NR with N,N'-substituted bis-(2,4-diamino-triazin-6-yl)-tetrasulfide

RSS1 100 100 Ultra VN 3 grains 50 50 ZnORs 5 5 Stearic acid 2 2 NaftoleneZD 3 3 Vulkanox 4010NA 2.5 2.5 Vulkanox HS 1.5 1.5 Protector G 35 1 1 VulkacitMOZ 1.43 — D — 7 Sulfur 1.5 — ^D max ^D (max+60') I 33.0 2- 7.8

max min at 170°C

Vulcanization temperature

Vulcanizate data (t 95%) at 170°C

Voltage value 300% 2.7 4.3

Sulfur-free crosslinking with N,N'-substituted bis-(2,4-diamino-triazin-6-yl)-tetrasulfide leads to a significant reduction of reversion in silica-filled natural rubber and, at the same time, to an increase in the stress value at 300%.

Example 30:

Acceleration of N 220/silica-filled NR with N,N’-substituted bis-(2,4-diamino-triazin-6-yl)-tetrasulfide

RSS1 100 100 100 100 100 100 100 CORAX N 220 25 25 25 25 25 25 25 Ultra VN 3 grains 25 25 25 25 25 25 25 ZnORS 5 5 5 5 5 5 5 Stearic acid 2 2 2 2 2 2 2

-21- 270 302

Example 30:

NaftoleneZD 3 3 3 3 3 3 3 Vulkanox4010NA 2.6 2.5 2.5 2.6 2.5 2.5 2.5 VulkanoxHS 1.5 1.6 1.5 1.5 1.6 1.5 1.5 ProtectorG35 1 1 1 1 1 1 1 VulkacitMOZ 1.43 — — — — — B — 2 3 4 6 6 7 Sulfur 1.5 0.51 0.78 1.02 1.27 1.53 1.79 ^D max ^D (max+60') _v 44.7 3.2 1.7 0 0 0.8 1.7

-D .

max min bel17O°C

Vulcanization temperature Vulcanize data

1'95%) at 170 ^e C voltage value 300 %

3.6 3.5 5.5

7.0 8.3 9.2

9.8

Sulfur vulcanization with N,N'-substituted bis-(2,4-diamino-triezin-6-yl)-tetrasulfide of N 220/clealic acid-filled NR reduces the reversion to 0% and leads to a strong increase in the stress value.

Example 31:

Acceleration of silica-filled NR with N,N'-substituted bis-(2,4-diamino-triazi i-6-yl)-tetrasulfide

RSS1 Ultra VN 3Gran.

ZnORS Stearic acid NaftolenZD Vulkanox4010NA VulkanoxHS ProtectorG35 VulkacitMOZ B

Sulfur θ max ^D (max+60')

D - D . max mm at 170°C vulcanization temperature Vulcanizate data (t95%) at 170°C Stress value 300%

100 100 50 50 5 5 2 2 3 3 2.5 2.5 1.5 1.5 1 1 1.43 — — 7 1.5 1.79 ^% 33.0 4.5 2.7 5.3

The sulfur vulcanization with N,N'-substituted bis-(2,4-diamino-triazin-6-yl)-tetrasulfide of silica-filled NR is almost reversion-free and increases the stress value by 300%.

Example 32:

Acceleration of N 220/silica-filled NP with N,N'-substituted bis-(2,4-diamino-triazin-6-yl)-tetrasulfide in the presence of Si 69

RSS 100 100 100 CORAX N 220 25 25 25 Ultra VN 3 grains 25 25 25 Si69 3.75 3.75 3.75 ZnORS 5 5 5 Stearic acid 2 2 2 NaftoleneZD 3 3 3 Vulkanox4010NA 2.5 2.5 2.5 VulkanoxHS 1.5 1.5 1.5 ProtectorG35 1 1 1 Vulkacite MOZ 1.43 — — B — 2 3 Sulfur 1.5 0.49 0.74

Example 32:

¹³ max ^D (max+60 ¹ ) ________________________ a 18.1 0 0 D -D .

max mm at 170 ^e C

Vulcanization temperature

Volcanic saturation data (t 95%) at 170’C

-22- 270 302

Voltage value 100% 1.4 1.6 2.4 Voltage value 200% 3.5 4.6 7.3 Voltage value 300% 7.1 9.5 13.9

Acceleration with N,N'-substituted bis-(2,4-diaminnotriazin-6-yl)-tetrasulfide in the presence of Si 69 allows the reversion to be reduced to 0% with a simultaneous strong increase in the voltage values.

Example 33:

Acceleration of silica-filled NR with N,N'-substituted bis-(2,4-d1amino-triazin-6-yl)-tetrasulfide in the presence of Si 89

RSS1 100 100 100 100 Ultra VN 3 grains 50 50 50 50 SI69 7.5 7.5 7.5 7.5 ZnORS 5 5 5 5 Stearic acid 2 2 2 2 NaftoleneZD 3 3 3 3 Vulkanox4010NA 2.5 2.5 2.5 2.5 VulkanoxHS 1.5 1.5 1.5 1.5 ProtectorG35 1 1 1 1 VulkacitMOZ 1.43 — — — B — 2 3 4 Sulfur 1.5 0.49 0.74 0.99 ^max ^D (max+60 ¹ ) 16.6 D -D . ^% 0 0 0

max mm at 170’C

Vulcanization temperature VUkanisatdaten (t95%) at 170’C

Voltage value 100% 1.5 1.7 2.5 3.2 Voltage value 200% 3.4 4.3 6.6 8.3 Voltage value 300% 6.3 8.2 12.3 15.0

Even in the case of pure silica filling, NR is vulcanized in the presence of Si 69 with N,N'-substituted bis-(2,4-diamino-triazin-6-yl) tetrasulfide and sulfur without reversion, whereby at the same time the stress level is increased very strongly.

Example 34:

The sulfur-free crosslinking of N 220/silica-filled NR with N,N'-substituted B ^! s-'2,4-diamino-triazin-6-yl)· tetrasulfide in the presence of Si 69

RSS1 100 100 100 100 100 CORAX N 220 25 25 25 25 25 Ultra VN 3 grains 25 25 25 25 25 Si69 3.75 3.75 3.75 3.75 3.75 ZnORs 5 5 5 5 5 Stearic acid 2 2 2 2 2 NaftoleneZD 3 3 3 3 3 Vulkanox4010NA 2.5 2.5 2.5 2.5 2.5 VulkanoxHS 1.5 1.5 1.5 1.5 1.5 Protector G 35 1 1 1 1 1 VulkacitMOZ 1.43 — — — — D — 1 2 3 4 Sulfur 1.5 — — — —

Example 34: ^D max ⁰ (max+60 ¹ ) ,, -23- 270 302 18.1 0 0 0 0 D-0 . max mm bell 70°C Vulcanization temperature Vulcanize data (t95%) at 170°C modulus 200% 3.5 2.6 4.9 6.5 8.6 Voltage value 300% 7.1 5.8 10.2 12.9 16.0

The sulfur-free crosslinking of N,N'-substituted Bls-(2,4-diamlno-triaz ^! 6-yl)-tetrasulfide in natural rubber with carbon black and silica filling leads, even with the addition of Si 69, to a simultaneous prevention of reversion and a strong quantity-dependent increase in the stress value.

Example 35:

The sulfur-free crosslinking of cleavage acid-filled NR with I^,N'-substituted bis-(2,4-diamino-triazin-6-yl)-tetrasulfide in the presence of Si 69

RSS1 100 100 100 100 100 O'clock. 3 grains. 50 50 60 50 50 Si69 7.5 7.5 ’ ,d 7.5 7.5 ZnORS 5 6 6 5 5 Stearic acid 2 2 2 2 2 NaftoleneZD 3 3 3 3 3 Vulkanox4010NA 2.5 2.5 2.5 2.5 2.5 VulkanoxHS 1.5 1.5 1.5 1.5 1.5 ProtectorG 35 1 1 1 1 1 VulkacitMOZ 1.43 — — — — D — 1 2 3 4 Sulfur 1.5 — — — — D-D . , , _n ix max (max+60 ¹ ) 16.6 L 0 0 0 0 D~D . max min at 170 ^° C Vulcanization temperature Vulcanizate data (t 95%) at 170°C Voltage value 200% 3.4 2.8 3.9 ^- 5.0 7.6 Voltage value 300% 6.3 5.0 7.6 11.3 13.9

The crosslinking with N,N'-substituted bis-(2,4-diamino-triazin-6-yl)-tetrasulfide of natural rubber with pure silica filling in the presence of Si 69 also succeeds without reversion and simultaneously leads to a strong increase in the stress value.

Claims (10)

Patent claims: 1. Process for the preparation of N,N'-substituted bis-(2,4-diamino-s-triazin-6-yl)-tetrasulfides of the general formula (I) in which mean: R\R ² = H,R ² = benzyl, R ² , R ³ , R ⁴ = Ci-Ce-alkyl, C3- _C8- cycloalkyl, the latter unsubstituted or substituted with 1-3 methyl groups, 2-hydroxyethyl, 3-hydroxypropyl, -2-hydroxypropyl or R ³ and R ⁴ (together): C ₄ -C ₆ -alkylene,-(CH2-CHX) ₂ Y with X = H, CH ₃ , Y = / O, S, characterized in that an aqueous alkaline solution of the corresponding N,N'-substituted 2,4-diamino-6-mercaptotriazines is reacted in a two-phase system with a solution of S2-Cl2 in an inert organic solvent which does not dissolve or only slightly dissolves the resulting tetrasulfide. 2. A process for the preparation of the tetrasulfides according to claim 1, characterized in that the minimum stoichiometric amount of alkali hydroxide necessary for the reaction is used. 3. Process according to claim 1 and 2, characterized in that an excess of 1-20 mol%, based on the mercaptotriazine, is used. 4. Process according to claims 1 to 3, characterized in that sodium or potassium hydroxide is used and, as solvent, Cs-Cw alkanes or C ₆ -C ₈ cycloalkanes, optionally substituted with 1-3 methyl groups. 5. Vulcanizable mixtures based on one or more natural and/or synthetic rubbers (S) containing fillers, sulfur and other conventional constituents, characterized in that they contain 0.01-1 parts, preferably 0.1-5 parts, per 100 parts of rubber of the compounds according to claims 1-4 and mixtures thereof and/or mixtures with conventional accelerators, with sulfur dosages of 0.1-1 parts per 100 parts of rubber. 6. Vulcanizable mixtures according to claim 5, characterized in that they contain the retarder N-phenyl-N-(trichloromethylsulfonyl)-benzenesulfonamide and the compounds according to claims 1-4 or mixtures thereof in a molar ratio of 0.5-1.5:1, preferably 0.8-1.2:1, with a sulfur dosage of 0.1-10 parts by weight per 100 parts of rubber, preferably 0.58 part based on 100 parts of rubber. 7. Vulcanizable, sulfur-free mixtures based on one or more natural and/or synthetic rubbers containing fillers and other conventional constituents, characterized in that they contain 0.2-15 parts, preferably 0.3-8 parts, of the compounds or mixtures thereof according to claims 1-4 per 100 parts of rubber or mixtures with conventional accelerators. 8. Vulcanizable mixtures according to claim 7, characterized in that they contain the retarder M-phenyl-N-((rir,chloromethylsulfenyl)-benzenesulfonamide) and the compounds according to claims 1-4 or mixtures thereof in a molar ratio of 0.5-1.5:1, preferably 0.8-1.2:1, per 100 parts of rubber. 9. Vulcanizable mixtures according to claims 5 to 8, characterized in that they contain only silicas as fillers. 10. Vulcanizable mixtures according to claims 5 to 8, characterized in that they contain, as filler, in addition to carbon black, more than 15 parts of silica per 100 parts of rubber.