Rubber compound for passenger car tire treads

Abstract

FIELD: rubber production.SUBSTANCE: rubber mixture based on a combination of natural, synthetic butadiene and oil-filled butadiene-styrene statistical rubbers with a high content of 1.2 links, containing carbon black and a silica filler can be used in the tire industry for the tread of passenger car tires with a road pattern. A rubber compound for the tread of summer passenger car tires containing 74÷80 pts. wt. of natural rubber, 10÷15 pts. wt. of butadiene rubber BR, 13÷15 pts. wt. of synthetic styrene-butadiene rubber with a high content of 1.2 units, oil-extended with the following ratio of components in pts. wt. per 100 pts. wt. of polymers: 47÷53 active grade carbon black, 30÷35 silica filler with a specific surface area of 175 m2 / g, 2.0÷4.5 processed distilled aromatic extract, 8÷12 terpene-phenolic resin, 0.5÷2.0 mixture of fatty acids and zinc salts, 0.5÷1.5 zinc soaps of fatty acids, 4.11÷4.8 Bis-(3-(triethoxysilyl)propyl)-polysulfide, 2.5÷3.0 zinc oxide, 2.0÷3.0 mixture of predominantly saturated fatty acids, 1.0÷1.5 (1,3-dimethylbutyl)-N-phenyl-n-phenylenediamine, 1.0÷1.5 mixtures of diaryl-p-phenylenediamine, predominantly ditolyl, 1.5÷3.0 microcrystalline wax, 1.5÷3.5 sulfur, 1.0÷1.8 N-T-butyl-2-benzothiazolesulfenamide, 0.1÷0.3 N-Cyclohexylthiophthalamide.EFFECT: increased grip on wet roads while maintaining low rolling resistance and wear resistance of the tire.1 cl, 1 dwg, 2 tbl, 2 ex

Description

[0001] The invention relates to a rubber compound based on a combination of natural and synthetic butadiene and oil-extended styrene-butadiene rubbers with a high content of 1.2 units, containing carbon black and a silica filler. The rubber compound is applicable in the tire industry for the tread of passenger car tires with a road pattern.

[0002] A technical solution is known (patent RU 2129131, priority date 08.11.1995), providing for the use of a rubber compound based on unsaturated rubbers, including butadiene rubber, as a tread for winter tires. The technical solution closest to the invention in terms of technical essence is (patent RU 2635803, published 16.11.2017), used for the tread of high-speed passenger car tires with improved grip properties. In rubber compounds of this type, solution-based styrene-butadiene rubber, cis-butadiene rubber on a neodymium catalyst, and a small proportion of natural rubber are used as the main polymer. The prototype was a rubber mixture with the following ratio of components in parts by mass per 100 parts by mass of polymers:

[0003] Solution-based styrene-butadiene rubber with added oil grade TDAE 95,0÷115 normalized for the content of polycyclic aromatic hydrocarbons - including styrene butadiene rubber 90,0÷88,0 TDAE oil 5,0÷27,0 Cis-butadiene rubber on neodymium 5,0÷10,0 catalyst Natural rubber grade STR 5,0÷8,0 Ground sulfur 1,4÷2,4 Vulcanizing group 3,0÷6,5 including zinc oxide 1,0÷2,5 N,N-Diphenylguanidine 1,0÷2,5 Stearic acid 1,0÷1,5 Silica filler with a specific surface area of ​​165 m2 / g 80,0÷85,0 Wax-based stabilizer 1,5÷2,5 microcrystalline Anti-aging agents 3,5÷5,0 including polymerized 2,2,4-trimethyl-1,2 dihydroquinoline 1,5÷2,5 N-(1, 3-dimethylbutyl)-N'-phenyl- n-phenylenediamine 2,0÷2,5 Technological additive based on a mixture fatty acid derivatives in the form of zinc soaps 2,0÷4,0 The coupling agent is bis-[3-(triethoxy) silylpropyl]-tetrasulfide 12,0÷16,0 Hydrocarbon maleated resin 2,5÷3,5 Plasticizer oil, normalized to content of polycyclic aromatic 6,0÷10,0 hydrocarbons

[0004] The rubber compound in the specified technical solution does not have sufficiently high grip properties on wet roads.

[0005] The prototype of the present invention of a rubber compound for the tread of passenger car tires based on a combination of rubbers is a technical solution protected by Russian patent No. 2635803, published on November 16, 2017.

[0006] The objective of this invention is to develop a rubber compound formulation for the tread of passenger car tires that provides better grip on wet roads while maintaining low rolling resistance and wear resistance of the tire.

[0007] In order to achieve the technical result, research work was carried out, an improved formula for the rubber compound was selected, the composition and optimal content of each ingredient in the rubber compound were selected empirically, allowing for the maximum achievement of the stated technical result.

[0008] A rubber compound for the tread of summer passenger car tires has been developed based on a combination of natural, synthetic butadiene SKD and oil-filled butadiene-styrene statistical rubber with a high content of 1.2 links, active grade carbon black, silica filler with a specific surface area of ​​175 m 2 / g, plasticizer from a mixture of processed distilled aromatic extract and terpene-phenolic resins, technological additives from a mixture of zinc soaps of fatty acids and a mixture of fatty acids and zinc salts, silane crosslinking agent from a mixture of bis(3-(triethoxysilyl)propyl)-polysulfide, vulcanization activators from a mixture of zinc oxide and a mixture of predominantly saturated fatty acids, antioxidants from a mixture of (1,3-dimethylbutyl)-N'-phenyl-n-phenylenediamine and a mixture of diaryl-p-phenylenediamine, predominantly ditolyl, such as tolylphenol and diphensil, microcrystalline wax, vulcanizing agent - sulfur, vulcanization accelerator from a mixture of N-Treatbutyl-2-benzothiazolesulfenamide, antiscorching agent N-Cyclohexylthiophthalamide in the following ratio of components in parts by weight per 100 parts by weight polymers:

[0009] Natural rubber 74÷80 Butadiene rubber SKD 10÷15 Synthetic butadiene-styrene statistical rubber high 1.2 link, oil-filled 13÷15

[0010] Filler:

[0011] Active grade carbon black 47÷53 Silica filler with a specific surface area of ​​175 m2 / g 30÷5

[0012] Plasticizer:

[0013] Processed distilled aromatic extract 2,0÷4,5 Terpene-phenolic resin 8÷12

[0014] Technological additive:

[0015] A mixture of fatty acids and zinc salts 0,5÷2,0 Zinc soaps of fatty acids 0,5÷1,5

[0016] Silane crosslinking agent:

[0017] Bis(3-(triethoxysilyl)propyl)-polysulfide 4,11÷4,8

[0018] Vulcanization activator:

[0019] Zinc oxide 2,5÷3,0 A mixture of predominantly saturated fatty acids 2,0÷3,0

[0020] Anti-aging agent:

[0021] (1,3-dimethylbutyl)-N'-phenyl-n-phenylenediamine 1,0÷1,5 A mixture of diaryl-p-phenylenediamine, predominantly digolyl 1,0÷1,5 microcrystalline wax 1,5÷3,0

[0022] Vulcanizing agent:

[0023] Sulfur 1,5÷3,5

[0024] Vulcanization accelerator:

[0025] N-Treatbutyl-2-benzothiazolesulfenamide 1,0÷1,8

[0026] Antiscorching:

[0027] N-Cyclohexylthiophthalamide 0,1÷0,3

[0028] Trial rubber compound samples were manufactured in three variants (a prototype and two experimental variants according to the present invention). Table 1 compares the compositions of the proposed rubber compound and the known one (prototype) using average component values.

[0029]

[0030] The use of natural rubber helps maintain elasticity and improve abrasion and tear resistance.

[0031] Rubbers based on a small proportion of cis-butadiene rubber, a linear structure and a high content of cis 1,4-units (96-98%) have the best combination of properties in terms of wear resistance and crack resistance.

[0032] The introduction of synthetic butadiene-styrene statistical with a high content of 1.2 links, oil-filled rubber provides rubber with strength indicators, improves the properties of wet adhesion while reducing rolling losses. The use of active grade carbon black improves mechanical properties.

[0033] The reinforcing filler used is silica filler with a specific surface area of ​​175 m 2 / g, which allows for dynamic material properties that cannot be achieved with carbon black. Improved material properties, such as lower rolling resistance and high traction, are particularly important for tread rubber compounds.

[0034] Increased dynamic properties are achieved by adding a silane crosslinking agent based on bis(3-(triethoxysilyl)propyl)-polysulfide to the rubber mixture.

[0035] Microcrystalline wax-based stabilizers and long-lasting antioxidants based on N-(1,3-dimethylbutyl)-N'-phenyl-n-phenylenediamine, a mixture of diaryl-p-phenylenediamine, predominantly ditolyl, are used as protection against fatigue properties, the effects of heat and ozone.

[0036] The introduction of processed distilled aromatic extract as a plasticizer ensures an increase in the plastic-elastic properties of the rubber compound.

[0037] The addition of terpene-phenolic resin ensures optimal technological and rheometric properties of rubber compounds, as well as the quality of profiled products. It improves the properties of rubber compounds and tire performance (wet grip).

[0038] Replacing the N,N-Diphenylguanidine accelerator with the N-T-butyl-2-benzothiazole sulfenamide vulcanization accelerator with a selected group of vulcanization activators (from a mixture of zinc oxide and a mixture of predominantly saturated fatty acids) while maintaining the sulfur vulcanizing agent, allows for the optimization of the vulcanization process of the rubber compound, providing increased strength, reduced heat generation, and good wear resistance.

[0039] To improve the technological properties of the rubber compound, technological additives from a mixture of zinc soaps of fatty acids and a mixture of fatty acids and zinc salts were introduced into the rubber compound.

[0040] The introduction of anti-scorching agent N-Cyclohexylthiophthalamide provides reliable protection of rubber from premature vulcanization.

[0041] The rubber compound of the present invention is designed for production on standard tire industry equipment using standard technologies.

[0042] The results of laboratory tests of the developed rubber compound variants and the prototype, carried out using standard test methods, are shown in Table 2, Fig. 1.

[0043] The test results of the prototype and samples of rubber compounds according to the present invention confirm that the developed rubber compound for the tread of passenger car tires achieves the stated technical result, namely, wet road grip while maintaining low rolling resistance and wear resistance of the tire.

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