RU2548066C1 - Vulcanisable rubber mixture - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: rubber mixture contains the following, wt %: SKI-3 rubber 67.60-68.80, stearic acid 1.30-1.40, zinc oxide 3.30-3.50, sulphur gas 1.50-1.60, sulphenamide T 0.40-0.50, technical carbon N330 23.60-24.10, modifier - N-alkyl-4-nitroso-3-methyl-5-(2-naphthyl)-pyrazole 0.30-2.10. The alkyl is methyl or propyl or isopropyl. The modifier is obtained via catalytic step-by-step condensation of functionalised 1,3-diketone, amine and ketone.

EFFECT: invention improves the polymer-filler reaction and processing characteristics of vulcanised rubber.

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Description

The invention relates to the technology of rubber products, in particular to methods for volumetric modification of rubbers in order to transform the structure of the elastomeric composition at the stage of its manufacture to increase the effective life of the products by improving technical characteristics.

Rubber mixtures are known in which C-nitroso compounds are used - derivatives of p-phenylenediamine (PNDFA) having a promoting and stabilizing activity [Koshelev F.F., Kornev A.E., Bukanov A.M. General technology rubber. M .: Chemistry. 1978. 528 p.]. The use of PNDFA allows to obtain rubber with high resistance to thermal effects in a wide temperature range.

The disadvantage of using PNDFA and its derivatives is increased migration activity (especially when in contact with liquid aggressive media) and the presence of carcinogenic impurities.

A well-known rubber mixture containing as a modifier spatially hindered C-nitroso compounds [Lyubyashkin A.V., Goncharov E.V., Suboch G.A., Tovbis M.S. Sat tr Intl. Conf. “Technical chemistry. From theory to practice. ” Permian. 2008.V.3. S.218-219], which exhibit the properties of anti-fatigue agents and affect the vulcanization parameters of the vulcanization process.

The disadvantage of the used heterocyclic nitroso compounds is their limited solubility in the elastomeric matrix, leading to an inhomogeneous distribution in the volume of the composition.

The invention solves the problem of improving the technical characteristics of rubber products.

The technical result consists in increasing the strength of the vulcanizates and increasing the degree of polymer-filler interaction.

The specified technical result is achieved by the fact that a vulcanizable rubber mixture containing SKI-3 1,4-cis-isoprene rubber, stearic acid, zinc oxide, gas sulfur, sulfenamide T, carbon black N 330, a modifier, contains N-alkyl as a modifier -4-nitriso-3-methyl-5- (2-naphthyl) pyrazole, where alkyl is methyl, or propyl, or isopropyl, with the following components, wt.%:

Rubber SKI-3 67.60-68.80 Stearic acid 1.30-1.40 Zinc oxide 3.30-3.50 Sulfur gas 1.50-1.60 Sulfenamide T 0.40-0.50 Carbon black N 330 23.60-24.10 N-alkyl-4-nitriso-3-methyl-5- (2-naphthyl) pyrazole 0.30-2.10

The use of three-component condensation products of functionalized 1,3-diketone, amine and ketone, which have increased solubility in the matrix of the carbochain elastomer and do not migrate from the polymer matrix due to steric hindrances and significant molecular weight in rubber compounds, allows to obtain modified products with increased strength.

The invention is illustrated by the following examples.

Example 1

Л.The rubber mixture (without modifier) of the 1,4-cis-isoprene rubber SKI-3 (GOST 14924-75) - 68.99 wt.%, Stearic acid (GOST 6484-96) - 1.38 wt.%, Zinc oxide (GOST 10262-73) - 3.45 wt.%, Gas sulfur (GOST 127.1-93) - 1.55 wt.%, Sulfenamide T (TU 2491-277-00204168-96) - 0.48 wt.%, carbon black N 330 (TU 38.41558-97) - 24.15 wt.% is made on the basis of a roller mixer $$320\frac{160}{160}$$

L.

In the manufacture of the rubber mixture, the ingredients are introduced in the following order: SKI-3 rubber, stearic acid, zinc oxide, gas sulfur, carbon black N 330, sulfenamide T. The temperature of the mixture is 70 ° C. The total production time of the mixture is 20 minutes

Example 2

Obtaining a modified rubber compound by the method of the prototype differs from that presented in example 1 in that after the introduction of all the ingredients, a modifier is additionally introduced - 5-methyl-4-nitroso-3- (2-naphthyl) -1H-pyrazole in an amount of 0.69 wt. % obtained by the method [Lyubyashkin A.V., Goncharov E.V., Suboch G.A., Tovbis M.S. Sat tr Intl. Conf. “Technical chemistry. From theory to practice. ” Permian. 2008.V.3. S.218-219]. The temperature of the mixture is 70 ° C. The total production time of the mixture is 20 minutes

Example 3

Obtaining a modified rubber compound according to the present method differs from the prototype presented in example 2 in that 1,3-dimethyl-4-nitroso-3- (2-naphthyl) pyrazole obtained by the method [Lyubyashkin A.V. ., Zadov V.E., Sokolenko V.A., Tovbis M.S. Synthesis of alkyl substituted aminopyrazoles with a 2-naphthyl substituent. “News of higher educational institutions. Series: Chemistry and Chemical Technology. 2010.V. 53. Number 4. C.3-5], in an amount of 0.34 wt.%. The temperature of the mixture is 70 ° C. The total production time of the mixture is 20 minutes

Example 4

Obtaining a modified rubber compound according to the present method is analogous to example 3, and 1-propyl-3-methyl-4-nitroso-3- (2-naphthyl) pyrazole obtained by the method [Lyubyashkin A.V., Tovbis is additionally introduced as a modifier M.S. Synthesis of alkyl substituted nitrosopyrazoles with a 2-naphthyl substituent. “News of higher educational institutions. Series: Chemistry and Chemical Technology. 2008.V. 51. No. 11. S.50-52], in an amount of 1.03 wt.%. The temperature of the mixture is 70 ° C. The total production time of the mixture is 20 minutes

Example 5

Obtaining a modified rubber mixture according to the present method is analogous to example 3, and 1-isopropyl-3-methyl-4-nitroso-3- (2-naphthyl) -pyrazole obtained by the method [Lyubyashkin A.V., Tovbis is additionally introduced as a modifier M.S. Synthesis of alkyl substituted nitrosopyrazoles with a 2-naphthyl substituent. “News of higher educational institutions. Series: Chemistry and Chemical Technology. 2008.V. 51. No. 11. S.50-52], in an amount of 2.03 wt.%. The temperature of the mixture is 70 ° C. The total production time of the mixture is 20 minutes

Table 1 presents the compositions of the rubber compounds according to examples 1-5.

The effect of spatially hindered nitrosopyrazoles on the degree of interfacial interaction was evaluated by changing the content of the filler-bound rubber (carbon-rubber gel) using the method described in [Tokareva M.Yu., Alekseeva I.K., Kavun S.M., Lykin A .FROM. About the reasons for the change in the effectiveness of p-nitrosodiphenylamine and stabilizers of the class p-phenylenediamine in filled rubbers from SKI-3. Rubber and rubber. 1980. No. 11. S.13-19].

Table 2 presents the structural characteristics of rubber compounds. It can be seen that the mixture modified by the proposed method (according to examples 3, 4, 5) has a high content of carbon-rubber gel, which indicates an increased level of interaction of the polymer with the filler. The content of the rubber associated with the filler in the modified compositions increased by 2 ÷ 31% relative to the control mixture (example 1).

The addition of C-nitrosopyrazoles proposed for the modification of elastomeric compositions (according to Examples 3, 4, 5) provides the vulcanizates with an increase of 2–23% in the nominal stress at 300% elongation, which is directly proportional to the density of the vulcanization bonds.

An increase in the degree of polymer-filler interaction (expressed by the content of carbon-rubber gel) and the formation of a denser vulcanization network, reflected in an increase in conditional stress at 300% elongation, leads to a change in the strength of the compositions. Vulcanizates based on compositions modified with C-nitroso compounds (according to Examples 3, 4, 5) have a strength level greater by 3–19% relative to the sample without a modifier.

The addition of C-nitrosopyrazoles to the elastomeric composition (according to Examples 3, 4, 5) leads to an increase in the dynamic fatigue endurance of vulcanizates in the set deformation mode by 1–31% in comparison with an unmodified sample.

Table 1 The composition of the rubber compounds Rubber compound ingredients The content of ingredients, wt.% The rubber mixture according to example one 2 3 four 5 Synthetic rubber 1,4-cis-polyisoprene SKI-3 68,99 68.52 68.75 68.28 67.59 Stearic acid 1.38 1.37 1.38 1.36 1.35 Zinc oxide 3.45 3.43 3.44 3.42 3.38 Sulfur gas 1.55 1,54 1.55 1,52 1,52 Sulfenamide T 0.48 0.48 0.48 0.48 0.47 Carbon black N 330 24.15 23.97 24.06 23.91 23.66 3-methyl-4-nitroso-3- (2-naphthyl) -1H-pyrazole - 0.69 - - - 1,3-dimethyl-4-nitroso-3- (2-naphthyl) pyrazole - - 0.34 - - 1-propyl-3-methyl-4-nitroso-3- (2-naphthyl) pyrazole - - - 1,03 - 1-isopropyl-3-methyl-4-nitroso-3- (2-naphthyl) pyrazole - - - - 2.03

table 2 Structural and elastic-strength characteristics of experimental compositions vulcanized at 142 ° C Rubber compound ingredients The rubber mixture according to example one 2 3 four 5 The content of carbon-rubber gel,% 22.8 27.3 23.3 27.0 29.8 Conditional strength at 300% elongation, MPa 16,0 18.3 16.3 18.1 19.7 Conditional tensile strength, MPa 20.8 23.7 21.5 23,4 24.8 Dynamic fatigue endurance, thousand centners (strain 150%; amplitude 250 min ^-1 ) 12.1 13.3 15.8 14.2 12,2

Claims (1)

Vulcanizable rubber mixture containing SKI-4 1,4-cis-isoprene rubber, stearic acid, zinc oxide, gas sulfur, sulfenamide T, carbon black N 330, modifier, characterized in that it contains N-alkyl-4 as a modifier -nitroso-3-methyl-5- (2-naphthyl) -pyrazole, where alkyl is methyl, or propyl, or isopropyl in the following components, wt.%:
Rubber SKI-3 67.60-68.80 Stearic acid 1.30-1.40 Zinc oxide 3.30-3.50 Sulfur gas 1.50-1.60 Sulfenamide T 0.40-0.50 Carbon black N 330 23.60-24.10 N-alkyl-4-nitroso-3-methyl-5- (2-naphthyl) pyrazole 0.30-2.10