RU2218366C2 - Rubber mixture for carcass-cushion rubbers - Google Patents

Abstract

FIELD: rubber-processing industry; tire production. SUBSTANCE: the invention relates to the field of the rubber mixtures used for carcass-cushion rubbers production. The rubber mixtures used for the carcass-cushion rubbers contains (mass share): synthetic cis-1.4-polyizoprene with contents of links in a cis-position of no less than 96 % - 70-90, natural rubber - 10-30, a vulcanizing group - 4.5-6.0, the activator - zinc white - 1.0-5.0, dispersing agent - 2.0-4.0, plasticizers - 10.0-15.0, antiscorching - 0.3-0.6, filler - technical carbon - 50-70, rubber production wastes - 10-17. At that natural rubber is presented in an unplasticized state. Such mixture is prepared in a masticator. EFFECT: improved adhesiveness, cohesive strength of elastic - strength and dynamic parameters of rubbers. 2 tbl, 3 ex

Description

 The invention relates to the tire industry and for the development of rubber compounds for frame-belt rubber. The most important indicators of frame-belt rubber mixtures are cohesive strength, adhesiveness, and vulcanizates - fatigue-resistance properties, temperature resistance, resistance to thermal aging, high bond strength with cord, low hysteresis and maintaining the high level of the above indicators during the operation of tires. Previously, frame-belt rubber compounds were made on the basis of the combinations NK-BSK, NK-SKD-BSK [Penn B.C. Technology for processing synthetic rubbers. Mixing principles, processing technology and applications for synthetic rubbers of standard types. - M.: Chemistry, 1964. - 404 p.]. However, such combinations of rubbers do not provide the required set of properties and are not currently used. Rubber mixtures are also known for this purpose with a certain level of these indicators based on a combination of synthetic cis-1,4-polyisoprene (SKI-3) and natural rubber (NK), as well as mixtures based on each of these polymers [Kosso R.A. , Goncharova L.T. Composition and properties of belt rubber for lining steel cord tires of type R. / Tem. Review. - M.: TsNIITEneftekhim, 1991 - 64 p.].

 However, in the above cases, rubbers have a number of significant drawbacks: for example, in the manufacture of rubber compounds based on NK, mandatory preliminary plasticization of rubber is used. SKI-3 based rubber compounds have a very low cohesive strength, which makes it difficult to use in the formulation of frame-belt rubber. Rubber mixtures made on the basis of a combination of synthetic and natural polyisoprenes are most suitable for these purposes, although they also have a number of disadvantages: low cohesive strength of the crude mixtures, insufficient dynamic characteristics of the rubber, increased hysteresis, low bond strength with cord, and the need for binding preliminary mastication of rubber in the manufacture of rubber compounds.

 The closest technical solution is a rubber mixture (Technological regulations of OJSC YaShZ-465Sh-99 for the production of truck tires of diagonal design), which includes a combination of synthetic cis-1,4-polyisoprene (SKI-3) and natural rubber (NK), as well as a vulcanizing group, activator, dispersant, plasticizers, fillers, anti-scorching and rubber waste (table 1). However, this rubber mixture does not provide a high level of stickiness, cohesive strength, and the rubber based on it has an insufficient level of fatigue-resistance properties, resistance to heat aging, temperature resistance, bond strength with cord and increased relative hysteresis. To this it should be added that in the manufacture of the above mixture, natural rubber is used in the form of plastic compound, to obtain which it is necessary to carry out an additional technological operation - plasticization of the oil complex.

The objective of the invention is to improve the confection properties of mixtures (increase stickiness, cohesive strength), elastomeric and dynamic indicators of rubber, as well as reduce the cost of rubber compounds by eliminating the technological stage of plasticization of the NC and, ultimately, increase the operational characteristics of rubber. This problem is solved in that the rubber mixture for frame-belt rubber, including a combination of natural rubber NK and synthetic cis-1,4-polyisoprene SKI-3 with a cis position of at least 96%, the vulcanizing group, the activator is zinc white , dispersant, anti-scorching, plasticizers, filler - carbon black, rubber waste, contains natural rubber, presented in an unplasticized state, in the following ratio of ingredients, parts by weight per 100 parts by weight rubber:
Synthetic cis-1,4-polyisoprene SKI-3 with a cis position of at least 96% - 70 -90
Natural rubber NK - 10-30
Vulcanizing group - 4.5-6.0
Activator - zinc white - 1.0-5.0
Dispersant - 2.0-4.0
Plasticizers - 10.0-15.0
Anti-scoring - 0.3-0.6
Filler - carbon black - 50-70
Rubber Waste - 10-17
Along with rubbers, the inventive rubber composition contains the known and commonly used ingredients for tire rubbers: sulfur, sulfenamide "C" or "M", altax, captax, etc., united by the concept of a vulcanizing group; zinc white - activator, oleic or stearic acid - dispersant; petroleum bitumen, styrene-indene resin, rosin, protective wax, YaP-15U, PN-6Sh oil, etc. - plasticizers; phthalic anhydride, Santogard PVI - anti-scorching; carbon black with different dispersion, for example, of the following grades: P-514, P-234, N650, N339, etc. - filler, it is also possible to use modifiers (hexol, resorcinol-urotropin) to increase adhesion properties and also contain ingredients that reduce the cost of rubber - waste rubber production - finely ground rubber powder, crushed waste rubberized cord, crushed waste plastic film.

 As a result of the experiments, it was also found that the types of natural rubber: RSS 1, SVR-3L, SMR-5, etc., commonly used in the formulation of tire rubbers, in particular frame-belt, also do not affect the results of this invention.

 It should be noted that the main contribution to the formation of the properties of carcass-breaker rubbers in the invention is made by the presence in the formulation of unplasticized natural rubber, used in an amount of 10-30 parts by weight in combination with SKI-3. Non-plasticized NK rubber, which has not previously been subjected to any mechanical treatment, keeps its rubber structure unchanged, the natural components present in it are not destroyed, which, as you know, can have a positive effect on the properties of rubbers [Natural rubber / Ed. Roberts A. - M .: Mir - 1990, v. 1-2].

The effectiveness of the invention is illustrated by the following examples:
Example 1

The rubber mixture 1 (prototype) is prepared in a rubber mixer for 9 minutes (table. 1). The rubbers, activator, dispersant, anti-scorching, filler, plasticizers, rubber waste, vulcanizing group are sequentially loaded. Vulcanization is carried out at a temperature of 138 ^o C for 60 minutes

 Example 2

 Analogously to example 1, rubber mixtures of ciphers 2, 3, 4 are prepared. The vulcanization mode is the same.

 Example 3

 A mixture of cipher 5 is prepared as follows: unplasticized NK with highly dispersed carbon black is loaded into a rubber mixer, and then synthetic cis-1,4-polyisoprene and the remaining ingredients are added according to the recipe with a total mixing time of 9 minutes.

The vulcanization of the mixtures is carried out at a temperature of 138 ^o C for 60 minutes The test results of the mixtures and rubbers are presented in table 2.

 As follows from the data in Table 2, the use of unplasticized NK in the rubber compounds provides improved confection characteristics of the mixtures, the elastic-strength characteristics, the dynamic properties of the rubbers, the temperature resistance, the resistance to heat aging are significantly increased, the hysteresis losses are reduced, and the bond strength with the cord is increased. From the data of table 2 it also follows that the rubber mixture made according to example 3 (code 5), i.e. by mixing unplasticized nanocrystals with finely dispersed carbon black at the beginning of the mixing cycle, it also provides an increase in a number of physicomechanical parameters of rubbers and an improvement in the technological properties of mixtures.

 It should also be noted that when using non-plasticized natural rubber in frame-breaker mixtures in the claimed dosages from 10-30 wt. including the cost of rubbers is reduced due to the reduction of preparatory technological operations associated with the plasticization of NK, and the exclusion of expensive plasticizing additives. Ultimately, increasing the confection indicators of mixtures and the physicomechanical indices of rubbers provides higher performance characteristics of tires.

Claims (1)

Rubber mixture for frame-belt rubber, including a combination of natural rubber NK and synthetic cis-1,4-polyisoprene SKI-3 with a cis position of at least 96%, a vulcanizing group, an activator - zinc white, dispersant, anti-scorching, plasticizers , filler - carbon black, rubber waste, characterized in that natural rubber is presented in an unplasticized state in the following ratio of ingredients, parts by weight per 100 parts by weight rubber: Synthetic cis-1,4-polyisoprene SKI-3 with a cis position of at least 96% 70-90 Natural rubber NK 10-30 Vulcanizing group 4.5-6.0 Activator - white zinc 1.0-5.0 Dispersant 2.0-4.0 Plasticizers 10.0-15.0 Anti-scoring 0.3-0.6 Filler - carbon black 50-70 Rubber Wastes 10-17

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