SU938595A1 - Vulcanizable rubber stock - Google Patents

Abstract

VULCANIZABLE RUBBER MIXTURE based on synthetic rubber, including sulfur, carbon black and carbon dibasic dihydrazide, which, in order to improve the strength properties of thermo-oxidative aging of rubber from this mixture, additionally contains organic carboxylic acid of the general formula (ChopC). R, where R is alkyl, aryl, aralkyl, p 2t6, with the following ratio of components, weight, hours: Rubber 100 Sulfur 0.6-1.5 Soot., 40-45 Dihydrazide of two basic carboxylic acid 5-25 Carboxylic organic acid 5 -25

Description

The invention relates to vulcanizable rubber compounds based on synthetic rubbers and can be used in rubber engineering for the manufacture of parts resistant to oxidizing agents and high temperatures. A rubber compound based on synthetic rubbers is known, including a vulcanizing agent — sulfur, a filler — soot and a dihydrate of a two major organic carboxylic acid in the following ratio of ingredients, parts by weight: Ethylene propylene rubber 55–95 Butadiene nitrile rubber 5–45 Dihydrazil bipartite carbonaceous 555 12 Polytetrafluoroethylene 15-20 Metal oxides 8-12 Sulfur0.3-0.8 Peroxide4-10. Oligoether2-8 / Soot. 20-60 fl The main disadvantages of the known mixture are the low heat resistance of rubbers made of it when working under the conditions of oxidizing agents and high temperatures, and the composition is rather complicated. The aim of the invention is to increase the strength characteristics of vulcanizers in. the conditions of thermo-oxidative aging of rubber from this mixture and also the simplification of the composition of the rubber mixture. The goal is achieved by the vulcanizable rubber compound based on synthetic rubber, including sulfur, carbon black, and dibasic carboxylic acid dihydrazide, which contains a carboxylic organic acid of the general formula (nos) n, where R is alkyl, aryl, ara n, 2-6, at the following ratio of components, parts by weight: Rubber100 Sulfur 0.6-1.5 carbon black40-45 Dibasic carboxylic acid dihydrazide 5-25 Carboxylic organic acid 5-25 The positive effect of this mixture is due to the reaction of the condensation field between organic carboxylic acid th and dihydrazide organic dicarbonic acid vulcanization process of the rubber mixture according to the scheme /, K (HOOC; R + K- | -H2NHNC (0) (0 NHNH2- - C (0) NHNHC (0) -J (0) NHNHC (-H2 } tt 4H C {Oi- +2 (kni} H2Q, where ' is alkyl, aryl, aralkyl) n 2-6. The course of this reaction is proved by measuring the amount of water released during the vulcanization of rubber acid. The cyclization of the fragments proceeds and the formation of 1,3,4-bxadiazole systems. As digidraeidov dicarboxylic acids used dihydrazides of oxalic, malonic, glutaric, gtstsipinovoy, sebacic, azelaic, ierftsshevoy, tereftgshevoy, Adam coagulant, n-1,3-dicarboxylic, adamantane-1, 3-diacetic 1,1-diadamantil-3 3-dicarboxylic acids; as organic polycarboxylic acids - oxalic, malonic, - glutarric, adipic, sebacic, azelaic, isophthalic, terephthalic, adamantine: n-1,3-dicarboxylic, adamantane-1,3-diucetic, 1,1-diadmanthyl - dicarboxylic, trimetilitovuyu, pyromellitic, 1,1-dit adamantyl-3,3, 5,5-tetracarboxylic benzenepentacarboxylic, mellitic acids .. Instead of acids, you can use their anhydrides or acid halide. Examples 1-2. Preparation of the rubber mixture is carried out on laboratory rollers for 30 minutes, with the following component loading sequence: synthetic rubber, metal oxides, carbon black, sulfur, peroxide, dihydrazide, carboxylic acid. Vulcanization of the proposed and known mixtures is carried out in a press with electrical heating of the plates under the following conditions: I- for 60 minutes; P - at 165s for 60 minutes and for 60 minutes. Physicomechanical indicators are determined in accordance with the methods of GOST: 270-75 2b2-bSt 424: -63. The used dihydrazides are divided into the following groups: Td group dihydrazide acids: malonic, glutaric, adipic, sebacic, azelaic; groups 2D - dihydrazidfl acids: oxalic, adamantane-1,3-dicarboxylic, adamantane-1,3-daacetic, 1,1-diadamantyl-3,3-dicarboxylic; ; group-ZD-dihydrazide acids: isophthalic, tereftshevry. Used carboxylic acids: divided into the following groups: Group 1K-eshiphatic acids Group 2K-derivatives of adamantane Group ZK-derivatives of benzene The carboxylic acid – carboxylic acid hydrazide system is introduced into the mixture based on SKN-40 polar polyurethane (see Table 1, mixtures of 9-12) and saturated ethylenepro; Pilenovoi (SKEPM. tab. 2, mixtures 5-10). For comparison, rubber mixtures containing either only carboxylic acid were prepared (see Table 2, mixtures from Table 2, mixture 3, or only hydrazide (see Table 1, mixtures 2–4 and Table 2, mixture 3).

By a similar method, rubber mixtures containing polyhydrazide (the product of the reaction of polycondensation of carboxylic acid and hydrazide; see Table 1, mixture 8 and Table 2, mixture 4) and mixtures which do not contain the indicated compounds of compounds (see Table 1, mixture 1 and Table 2, mixture 1).

As can be seen from the table. 1 and 2, only with the joint introduction of a carboxylic acid and its hydrazide into a rubber mixture can vulcanizates with poEa strength characteristics be obtained under conditions of thermo-oxidative aging.

So the aging coefficients for durability "x rubbers" (see, table. 1, mixtures 9-12 and table. 2, mixtures

5-10) 1.5-2 times higher than that of the controls.

The proposed rubber compounds also have high initial strength characteristics. The hardening phenomenon of rubber is explained by the fact that under conditions of thermo-oxidative aging, there is a further interaction of dicarboxylic acids and their dihydrazides, and further thermo-oxidative heteropolycondensation of hydrazide fragments.

T: transfer them to an extremely stable 1,3, .4-oxydiazole system. In table. 3 shows the results

test of the rubber mixture and the proposed rubber mixtures. As a result of the introduction of polycarbonate acid and its dihydrazide into the rubber mixture, the initial strength characteristics increase 1.5 times and resistance to thermal-oxidative aging by a factor of 3-5. On the other hand, in addition to K1COKI strength

thermal aging indicators, the proposed rubber mixture does not contain a scarce and expensive product - polytetrafluoroethylene.

rubber from it on the basis of SKEP,

Control mixture

Ingredients

I: I: L: I:: IIII: I:: Dihydrazide: groups 1D groups 2D groups ZD Polycarbonate. Slots: groups 1K groups 2K groups LC Polyidrazides groups 1D 1K Resistance to rupture, Sha 13,813,612,3 Relative elongation,% Degree swelling in toluene for 24 hours, t 10,310,7102 Thermal aging at 150 ° C for 72 hours, K 0.750.830.73 0.400.620.7 Thermal aging at 150 ° C for 144 hours, K 0.20,310.26

table 2

Proposed Mixes

iU.TnE 5.5 -15.5 - 20 - 5.5 20 - 20 15 15 .614,614,213,913,114,213.9 02 85 8286 8388 84 96 100 99107 8991 83, 71,621,731,3 1,61,84 1,80 52 1, 1 1,501,31 1,421,52 1,63,340.18.1,10,96.1,200,700,96

Comparison of the proposed and well-known rubber compounds and rubbers of them

Table 3

Butadiene Nitrile Rubber

(SKN)

Ethylene Propylene Rubber (EPDM)

Polytetrafluoroethylene

Metal oxides

Oligoether

Sulfur

Peroxide

Soot

Dihydrazide

Polycarboxylic acid

Kaltaks

Stearin

Indicators of properties of tear resistance, MP

Relative elongation n gap,%

The degree of swelling in toluo

within 24 hours,%

Thermal aging coefficient:

K (125C, 72 hours).

K, (, 144 h) b

30 (5-45)

X

70 (55-95) 18 (15-20) 10 (8-12) 6 (2-8)

93

100

0.329

1.62 l, 0.310

Claims (1)

VULCANIZABLE RUBBER MIXTURE based on synthetic rubber, • including sulfur, soot and dihydrazide of dibasic carboxylic acid, characterized in that), in order to increase strength characteristics and conditions of thermooxidative aging of rubbers from this mixture, the latter additionally contains organic carboxylic acid of the general formula (HOOC ) _n R, where R is alkyl, aryl, aralkyl, η 2t6, in the following ratio of components, wt. Rubber 100 Sulfur 0.6-1.5 Soot 40-45 Dihydrazide two- main carbon howl acid 5-25 Carbonic organic acid 5-25 С0 СО 00 Си SB SI