RU2383562C2 - Method of preparing rubber mixture - Google Patents

Abstract

FIELD: chemistry. ^ SUBSTANCE: rubber mixture is obtained by adding ground up treated rubber crumb to a base rubber mixture. The base mixture used is frost-resistant B-14 butadiene-nitrile rubber mixture. The rubber crumb is further ground up and mechanically activated on a planetary mill. ^ EFFECT: simple process of making frost-resistant rubber articles with preservation of operational properties of the articles on the level of the base rubber mixture. ^ 3 tbl

Description

The invention relates to the rubber industry, to the production of composite materials for various purposes based on nitrile butadiene rubber using rubber crumb from waste tires and rubber products as a filler in order to develop the most efficient and minimally costly way of introducing it into new materials while maintaining the best performance properties matrices. It is known [1, 2] that by the time rubber products lose their performance, the polymer matrix itself undergoes relatively small structural changes.

Closest to the proposed invention is a method of processing rubber industry waste using modifying-regenerating compositions (MPC), which perform the functions of destructive agents, degradation activators and surface modifiers [3]. When choosing the components of the compositions, it was taken into account that the crumb contains a significant amount of active ingredients that did not react during vulcanization (including the main ones that provide highly elastic rubbers - vulcanizing agents) of the initial elastomer. Evaluation of the properties of tread rubbers containing crumb rubber treated with MPC showed that in terms of the set of properties they are practically not inferior to base rubber and correspond to standard indicators for this type of rubber.

The disadvantages of this method are to increase the material consumption of the manufacturing process of rubber compounds (MPC includes 2-4 additional ingredients) and the need for four additional process steps: 1) grinding waste, 2) preparation of MPC, 3) introduction of MPC in rubber crumb, 4) introduction MPC treated crumb rubber into the base rubber mixture.

The objective of the present invention is to reduce material consumption, simplify the manufacturing cycle of frost-resistant rubber products from base sealing rubber using mechanically activated rubber crumbs obtained from industrial rubber products as filler, while maintaining the operational properties of products at the level of products made from base rubber compounds. The frost-resistant butadiene-nitrile rubber mixture of industrial grade V-14 was chosen as the basic object of research. The composition of the mixture is presented in table 1.

Table 1 The composition of the rubber compound brand V-14 No. Ingredients m.ch. per 100 m.h. rubber one SKN-18, plastic 100.0 2 Sulfur 2.5 3 N, N-diphenylguanidine (DFG) 0.25 four Altax 2.7 5 Zinc white 7.5 6 Aldol-α-naphthylamine 4.0 7 Diafen FP 1,0 8 Paraoxineosone 1,0 9 Carbon black P803 130.0 10 Stearic acid 1,0 eleven Dibutyl phthalate 20,0 Total 269.95

Rubber crumb was obtained from technological (breakdown) waste products of the production of seals. The waste was crushed in a Fritch cutting mill; the size of the sieve used was 0.75 mm. Then the rubber crumb was subjected to mechanical activation at the AGO-2 planetary mill for 2 minutes, with a carrier speed of 890 rpm, a drum speed of 1820 rpm, acceleration of 600 m / s ² (60g), the ratio " crumb mass ”:“ mass of balls ”1:15. The raw rubber mixture was mixed with mechanically activated crumbs with a dispersion of 0.75 mm and a concentration of 20 wt.% Was carried out on rollers or a laboratory rubber mixer with Z-shaped blades. The resulting mixture was vulcanized on a vulcanizing press according to the standard for the rubber mixture B-14 mode.

Thus, the introduction of mechanically activated rubber chips does not require the introduction of additional ingredients in the rubber chips. During the mechanical activation of rubber crumb, the following occurs: firstly, the crumb of the rubber crumb and, most importantly, the activation of migration of the vulcanizing agent — sulfur, which did not react during vulcanization — to the surface of the rubber crumb. The reduction in the size of rubber crumb after mechanical activation is 4%. More developed vulcanization sulfide bonds appear in the system (46% more than when using unactivated chips, Table 2). The samples were tested that meet the requirements for frost-resistant sealing rubber: strength indicators according to GOST 270-75, frost resistance according to GOST 408-78, wear resistance to abrasion according to GOST 23509-79. This indicates effective co-vulcanization at the “rubber crumb - base rubber mixture” interface and contributes to an improvement in the performance of rubber filled with mechanically activated rubber crumb compared to rubber containing non-activated rubber crumb. At the same time, the strength properties remain at the level of the base rubber that does not contain rubber crumb, wear resistance during abrasion decreases, frost resistance increases (Table 3).

table 2 Sulfur content in rubber containing crumb rubber * Material Mas. total sulfur fraction Mas. free sulfur fraction Mac proportion of bound sulfur Bound sulfur / total sulfur,% Inactive crumb base rubber 0.506 0.056 0.450 50.6 Activated Crumb Base Rubber 0.641 0,021 0.620 96.7 * Tests conducted in accordance with GOST 28644-90.

Table 3 Properties of rubbers containing rubber crumb Properties Base tires V-14 without crumbs with inactive crumbs with activated crumb Conditional tensile strength, MPa 10.9 8.2 10,4 Relates. elongation at break,% 212 150 197 Coefficient of frost resistance at -45 ° С 0.96 0.58 0.98 Volumetric wear during abrasion, cm ³ 0,092 0,073 0.058

Feasibility

The use of the claimed invention, which is implemented on affordable and cheap equipment, makes it possible to rationally solve the problem of recycling rubber production waste, to reduce material consumption due to the use of mechanical activation of crumb rubber on a planetary mill before introduction into the base rubber compounds, which eliminates the introduction of additional chemical additives modifying the surface of the crumb rubber additives, and , accordingly, to exclude the operations of their preparation and introduction into the base rubber compounds, while rubber materials with high technical and operational properties.

Information sources

1. Ivanov S.R., Kruglova M.Yu., Platonova O.V., Oladov B.N. Current state of thermal methods for processing used tires and rubber waste. - M., 1985.

2. Smetanin V.I. Protecting the environment from production and consumption waste. - M .: Kolos, 2003 .-- 230 p.

3. Vashchenko Yu.N., Aleksandrov A.G., Sirchenko I.A., Zakharov Yu.I. Evaluation of the properties of elastomeric compositions containing modified rubber crumb / Rubber and rubber.- M .: 2001, No. 5, p.6-9.

Claims (1)

A method of producing a rubber mixture, including the introduction of processed crushed rubber crumbs from rubber waste into the base rubber mixture, characterized in that the base rubber compound is a frost-resistant butadiene-nitrile rubber mixture of grade B-14, and crumb is used as the processed rubber crumb, additionally subjected to grinding and mechanical activation on a planetary mill.