CS218183B1 - Organic vulcanization accelerators for isobutyl isoprene rubber, not harmful to health - Google Patents

Abstract

The invention belongs to the field of chemistry. It solves the elimination of the emission of harmful substances, especially carbon disulfide, during the processing of raw butyl rubber compounds. It consists in the fact that in a vulcanization system, usually containing sulfur and zinc oxide, a mixture of normal and basic zinc salts of Ο,Ο'-diesters of thiothiolphosphoric acid, especially 0-2-ethylhexyl-0-'-butyl ester of thiothiolphosphoric acid, together with 2,2'-dibenzothiazole disulfide are used as organic vulcanization accelerators. The invention can be used in rubber technology, especially in the production of air tubes for motor vehicles.

Description

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BACKGROUND OF THE INVENTION The present invention relates to the use of a mixture of normal and basic zinc salts of thionothiophosphoric acid, thionothiophosphoric acid 2,2'-dibenzothiazole disulfide and 2,2'-dibenzothiazole disulfide in an isobutylisoprene rubber sulfuric acid shortening system, abbreviated. referred to as butyl rubber.

Isobutyl isoprene rubber, abbreviated as " butyl rubber ", is found in all low gas permeability and good degradation resistance applications especially for automotive industry (bladders, mantle press membranes), construction (panel seals) ), production of cables (sheathing) and the like. As a result of the low insaturation required by zinc sulfur activated sulfur vulcanization, the presence of organic accelerators is present.

Conventionally used sulfur vulcanization systems containing, for example, tetramethylthiuram disulfide in combination with 2,2'-dibenzo-thiazole disulfide, provide the desired properties of the crude mixtures also with the respective vulcanizate, but in the processing process, for example mixing, extrusion and vulcanization. releases relatively high concentrations of chemical pollutants, polluting the environment of rubber plants. The main pollutant is carbon disulphide.

These disadvantages are overcome in practice by the use of a mixture of normal and basic zinc salts of thio-tertiophosphoric acid ma, Ο-diesters, in particular thionothiophosphoric acid 0-2-ethylhexyl-o-butyl ester together with 2.2. -dibenzotium, a bisulphide as an organic vulcanization accelerator, in a sulfur-free vulcanization system for isobutyl-zoprene rubber which does not release harmful substances.

The invention is based on the fact that it is not yet known that when used in the vulcanization of butyl rubber as the organic vulcanization accelerator, a mixture known as zinc salts Ο, Ο'-diesterkyl thionothiophosphoric acid and 2,2'-dibenzothiazole disulfide is used in vulcanizing systems that usually contain sulfur and zinc oxide, virtually releasing harmful substances is practiced. This is due to the appropriate structure of the zinc salt of thionothiophosphoric acid. Advantages of the use of the accelerator mixture according to the invention and the commonly used vulcanization system are illustrated in Tables 1 and 2, which contain the characteristics of rubber mixtures using vulcanization systems with 2,2 '-dibenzothiazole disulfide and tetramethylthiuram disulfide, with 2,2'-dibenzothiazole disulfide and O-2-ethylhexyl-O ' -butyl ester of thionothiophosphoric acid, respectively. only with tetramethyltriuram disulfide. or with thionothiophosphoric acid O-2-ethylhexyl O'-butyl ester.

Table 1

Zložkia vulk. system, mixture 1 mixture, 2 sulfur dsk *) 2,0 2,0 2,2, '- dibanzottiaizo] idiisulphide dsk 0,5 1,0 tetramethylthiuramdiisulphide dsk 1,0 mixture of normal and basic sulfuric acid 0-2-ethylhexyl -Ο'-butylasfer of thiophospholphosphoric acid dsk - 3.0 vulk. characteristics, Rheomete 100, 155 ° C - Ti, min, 4.3 4.3 - Tgo, min 30.5 33.5 - Rv, mim-1, 3.8 3.4 180 ° C: - T1 (min 1.9 1.7, - Tgo, min 7.2 7.6 - Rv, min-1 H8.8 16.9 physico-mechainic properties of vulkainizate - module M3O0, MFa 3.9 3.06 tensile strength MPa 10,3 12,7 - ductility,% 625 670 - hardness, ° Sh 58 46 - reflectance elasticity,% 17 16 - structure petty, k'N / m 26,04 26,35 restrained CS2 ·,% 0,23 100,000 parts by weight and 100 parts by weight of rubber From Table 1 it follows that although the vulcanization characteristics of the rubber compositions compared are very similar, there is a marked difference in the carbon disulphide released.

Table 2 shows the significant influence of Ο, Ο-diesters of thionothiophosphoric acid in the amount of carbon disulphide released compared to tetramethylthiuram disulphide.

Claims (2)

Use of a mixture of normal and basic zinc salts of thionothiophosphoric acid Ο, Ο'-diesters, in particular thionothiophosphoric acid 0-2-ethylhexyl-0'-butyl ester together with 2,2'-dibenzothiazole disulfide as organic non-release curing accelerators sulfur vulcanizone system for isobutylisoprene rubber.