SU678056A1 - Vulcanisable rubber mix - Google Patents

Description

(54) VOLKANIZABLE RUBBER MIXTURE

The invention relates to the rubber industry, in particular, it relates to the creation of durable, low-grade rubber vulcanizates based on graft copolymers for use in their electrical and cable industries. A vulcanizable rubber mixture based on a copolymer of ethylene propylene (rubber) with polyacrylamide is known, which includes a filler, for example, on the basis of a mixture of metal oxides kaolin l1. However, vulcanizates of a known rubber compound have a low npio4HocTbro and heat resistance. The purpose of the invention is to increase the strength and heat resistance of vulcanizates. This goal is achieved by those that, as a filler mixture, contains limestone to the composition, weight,% SiOg 0.02-0.65; AljOa 0.05-0.25; FejO 0.05-0.25, CaO 53.2-55.28; MgO 30.15-31.04; ZOZ 0.6-0.8, Impurities - the rest, Oxides, for example, Kjb, NajO, TiO ;, FeOV MpO, PgOg, cobalt oxides of sulfurous and phosphoric acid, and other inorganic compounds in an amount of from 15 up to 75 weight.h. per 100 weight parts copolymer. , Graft copolymer of ethylene-propylene rubber (EPA) with polyacrylamide (PAA) is obtained by copolymerization, EPA with acrylamide (AA) in toluene at 100 ° C for one hour in the presence of benzoyl peroxide. A graft copolymer containing 25 wt.% Grafted polyacrylamide is used to make rubber compounds. Example. Prepare a rubber mixture based on grafted EPA with PAA containing 2.0 parts by weight. dicumyl peroxide (MPC) and 30 weight parts. kaolin per 100 weight parts. rubber The mixture is prepared on laboratory rolls for 20 minutes at a temperature of 60 ° C, vulcanized at a temperature of 155 ° C for 40 minutes. Basic physical and mechanical properties of vulcanizates at Voltage at 300% - „nominal elongation, kg / cm Strength at break, kg / cm Elongation,% Residual elongation,%

Example 2. In Example 1, a rubber mixture was prepared based on the graft copolymer EPA with PAA. The mixture contains 2.0 weight.h. MPC and 30 weight.h. chalk per 100 weight.h. graft copolymer. The rubber mixture is vulcanized at 40 minutes.

Basic physical and mechanical parameters of volcanic eats :. Stress at 300% elongation, kg / cm 55.0 Strength at break, kg / cm85

Relative elongation,% 450 Residual elongation,% 25 Example 3. In Example 1, a rubber mixture is prepared based on

Stress at 300% elongation, kg / cm. Strength at break, kg / cm

Relative extension ,%

Residual elongation,% Elasticity on rebound,%

Resist the tear,

kg / cm Stress at 300% elongation, kg / cm 24 30 53 Strength 113 115 110 at break, kg / cm

grafted copolymer of EPA and PAA. The mixture contains 2.0 weight.h. MPC and 30 weight.h. limestone per 100 weight parts. copolymer. The choice of this filler is due to the fact that it contains a large number of various metal oxides that can interact with NHg, groups of grafted chains. The mixtures are vulcanized at 155 ° C for 40 minutes.

The main physicomechanical indicators of vulcanizates are given in table 1.

Table 2 shows an example of the rubber compounding, table 3 physical and mechanical properties of vulcanizates.

Table l

60 110

400 10

table 2

Table 60 52 60 55 74 110 100 105 85 100

Relative Note; The mixture is vulcanized. For comparison, the heat resistance properties of the vulcanizable rubber compound containing kaolin / n, 100 ° C for 96 h are given: Stress at 300% elongation, kg / cm Strength at break, kg / cm60 Relative tensile strength. % 350 Residual Elongation,% I 18 Thus, comparing the properties of known and proposed rubber compounds, it follows that the volcano nizata of the proposed rubber compounds have high strength properties and thermal stability, which makes it possible to recommend them for use in the electrical and machine-building industry, as well as in the production of rubber technical products.

Claims (1)

Continued table 3 -:. J at 15U s for 40 min. , Vulcanizable rubber compound based on a copolymer of ethylene-propylene rubber with polyacrylamide, comprising a filler, characterized in that, in order to increase the strength and heat resistance of vulcanizates, the filler mixture contains limestone, wt.% SiO20.020, 65; AlgO 0.05-0.25; Fe.O, 0.050, 25; CaO 53.2-55.28; MgO 30, 1531, 04; SOj 0.6-0.8, impurities rest, in an amount of from 15 to 75 weight.h. per 100 weight parts copolymer. Sources of information taken into account in the examination 1. Dontsov A.A. et al. The study of the vulcanization kinetics and the structure of heterogeneous rubbers with amides of acrylic and methacrylic acids. High Molecular Weight Compounds / 1, T (A) XVI, 1974, pp. 217-223.