Rubber mixture for production of rubber-metal products with increased weather resistance

Abstract

FIELD: rubber mixtures.SUBSTANCE: invention relates to a rubber mixture based on a combination of natural and chloroprene rubbers for the manufacture of rubber-metal products operating under conditions of exposure to atmospheric factors and intensive wear, used in the construction of machines, mechanisms of rolling stock, and technological equipment. The rubber mixture contains natural rubber, sulphur, stearic acid, N-cyclohexylbenzothiazole-2-sulfenamide, zinc oxide, N-Isopropyl-N'-Phenyl-p-Phenylenediamine, technical carbon P-514, chloroprene rubber of mercaptan regulation, magnesium oxide, 2,2,4-trimethyl-1,2-dihydroquinoline, protective wax, as well as an RFS system consisting of a silica filler with a specific surface area of 175, hexamethoxymethylmelamine and resorcinol-formaldehyde resin, in the following ratio of components, parts by weight:Chloroprene rubber with mercaptan regulation20.0-35.0 regulation20.0-35.0 Natural rubber 65.0-80.0 Natural rubber 65.0-80.0 Zinc oxide 5.0 Zinc oxide 5.0 Magnesium oxide 2.0 Magnesium oxide 2.0 Sulphur 2.0-2.5 2.0-2.5 N-cyclohexylbenzothiazole-2- sulfenamide3.0 sulfenamide3.0 Stearic acid 2.0 Stearic acid 2.0 N-Isopropyl-N'-Phenyl- p-Phenylenediamine2.0 p-Phenylenediamine2.0 2,2,4-trimethyl-1,2- dihydroquinoline 1.0 Protective wax 1.0 Carbon black P-51425.0-40.0 Carbon black P-51425.0-40.0 Silicic acid filler with specific surface area of 1755.0-15.0 specific surface area of 1755.0-15.0 Hexamethoxymethylmelamine3.0 Hexamethoxymethylmelamine3.0 Resorcinol-formaldehyde resin2.0 resin2.0EFFECT: increasing weather resistance and ensuring the “strength of the rubber-to-metal bond” parameter.1 cl, 2 tbl, 3 ex

Description

[0001] The proposed invention relates to the creation of a rubber mixture based on a combination of natural and chloroprene rubbers for the manufacture of rubber-metal products operating under conditions of exposure to atmospheric factors and intensive wear, used in the construction of machines, mechanisms of rolling stock, and technological equipment.

[0002] A known rubber mixture, adopted as a prototype, consists of natural rubber RSS-20 - 80.0 m.p., butadiene-styrene rubber SBR-1500 - 20.0 m.p., sulfur - 2.0 m.p., santocur (N-trebutylbenzothiazole-2-sulfenamide) - 0.6 m.p., zinc white - 5.0 m.p., stearic acid - 2.0 m.p., santhoflex 13 - 1.0 m.p., carbon black grades P514 - 65.0 m.p., paraffin oil Petrofin 2069 - 19.0 m.p. (O.M. Novopoltseva, V.F. Kablov, M.A. Krakshin “Materials and creation of formulations of rubber mixtures for the tire and rubber industry”, Volgograd, 2009. Table 2.16).

[0003] The disadvantage of the well-known rubber compound, which has high physical and mechanical properties, is its insufficient weather resistance and low efficiency of use in the construction of rubber-metal products.

[0004] The technical result consists in increasing weather resistance and ensuring the “strength of the rubber-metal bond” indicator.

[0005] The specified technical result is achieved by a rubber mixture for the production of rubber-metal products with increased weather resistance, containing natural rubber, sulfur, stearic acid, N-cyclohexylbenzothiazole-2-sulfenamide, zinc oxide, N-Isopropyl-N'-Phenyl-p-Phenylenediamine, technical carbon P-514, chloroprene rubber of mercaptan regulation, magnesium oxide, 2,2,4-trimethyl-1,2-dihydroquinoline, protective wax, as well as an RFS system consisting of a silica filler with a specific surface area of ​​175, hexamethoxymethylmelamine and resorcinol-formaldehyde resin, in the following ratio of components, parts by weight:

[0006] Mercaptan-regulated chloroprene rubber 20,0-35,0 Natural rubber 65,0-80,0 Zinc oxide 5,0 Magnesium oxide 2,0 Sulfur 2,0-2,5 N-cyclohexylbenzothiazole-2-sulfenamide 3,0 Stearic acid 2,0 N-Isopropyl-N'-Phenyl-p-Phenylenediamine 2,0 2,2,4-trimethyl-1,2-dihydroquinoline 1,0 Protective wax 1,0 Carbon black P-514 25,0-40,0 Silica filler with a specific surface area of ​​175 5,0-15,0 Hexamethoxymethylmelamine 3,0 Resorcinol formaldehyde resin 2,0

[0007] The use of natural rubber (RSS-1) in combination with chloroprene rubber of mercaptan regulation in combination with other ingredients, the introduction of magnesium oxide, 2,2,4-trimethyl-1,2-dihydroquinoline, protective wax, RFS system consisting of silica filler with a specific surface area of ​​175, hexamethoxymethylene melamine and resorcinol-formaldehyde resin in combination gives the desired result - increased weather resistance, ensuring the indicator of "strength of bond of rubber to metal" while maintaining high physical and mechanical properties.

[0008] Natural rubber is a natural product extracted from the sap of rubber-bearing plants. It is a high-molecular-weight diene hydrocarbon, a cis-polymer of isoprene. The key properties of natural rubber are its high strength and elasticity. RSS-1 (PT Perkebunan Nusantara) is a standard grade of natural rubber, distinguished from RSS-20 by its stable properties, higher strength and elasticity, and good crystallization ability. Mercaptan-regulated chloroprene rubber (Dalian Ftz Richon Intl Trade Co., Ltd) is a polymerization product of chloroprene. Due to its chemical structure—the presence of a chlorine atom in the molecule—this gives the rubber weather resistance, resistance to oxidation processes, and excellent adhesion to surfaces, including metal.

[0009] The rubber compound is vulcanized with sulfur (GOST 127.4-93), N-cyclohexylbenzothiazole-2-sulfenamide (Shenyang Sunnyjoint Chemicals Co., Ltd.), and zinc oxide (GOST 202-84). Magnesium oxide also acts as a vulcanizing agent and, additionally, as a hydrogen chloride scavenger and scorch retarder.

[0010] Zinc oxide (GOST 202-84) and stearic acid (GOST 6484-96) are used as activators of sulfur vulcanization.

[0011] To improve the bond strength of rubber with brass-plated steel, a modifying system (RFS system) has been introduced into its composition. It consists of a silica filler with a specific surface area of ​​175 (Quechen Silicon Chemical Co., Ltd.), resorcinol-formaldehyde resin (TU2221-020-08948815-2004) and hexamethoxymethylmelamine (SINO LEGEND (CHINA) CHEMICAL COMPANY LTD). The latter does not cause corrosion when in contact with zinc, bronze or steel coatings.

[0012] Carbon black P-514 (GOST 7885-86) acts as an active filler and gives the rubber compound optimal physical and mechanical properties and improved technological properties - calenderability, injection ability.

[0013] A combination of antioxidants was used as a stabilizing system: N-Isopropyl-N'-Phenyl-p-Phenylenediamine (Shenyang Sunnyjoint Chemicals Co., Ltd.), 2,2,4-trimethyl-1,2-dihydroquinoline (TU 2492-542-05763441-2013), protective wax (TU38.1011290-90).

[0014] The proposed composite material can use analogs of rubbers and ingredients produced by various companies.

[0015] The proposed rubber compound is manufactured under industrial conditions in a Banbury-type rubber mixer with intensive cooling. The initial temperature is 40±2°C. The rubbers are first decrystallized in a steam chamber.

[0016] Introduction of ingredients into the rubber mixer chamber is carried out in the following order:

[0017] 1. Add chloroprene and natural rubbers, stearic acid, N-cyclohexylbenzothiazole-2-sulfenamide, N-isopropyl-N'-phenyl-p-phenylenediamine, 2,2,4-trimethyl-1,2-dihydroquinoline, protective wax, magnesium oxide, resorcinol-formaldehyde resin, and silica filler. Mix for 2 minutes.

[0018] 2. Add technical carbon ½ P-514. Stir for 2-3 minutes.

[0019] 3. Add technical carbon ½ P-514. Stir for 1-2 minutes.

[0020] 4. Add sulfur and zinc oxide, hexamethoxymethylmelamine. Stir for 1 minute.

[0021] 5. Discharge the rubber mixture from the mixer for 1 minute.

[0022] 6. Mixing and plasticizing the rubber mixture on rollers with a gap between the rollers of 4-5 mm for 5 minutes.

[0023] 7. Cutting the rubber compound with a gap between the rollers of no more than 6 mm for 2 minutes.

[0024] Cooling the rubber mixture with sheets in a bath with artesian water at a temperature not exceeding 16 о WITH.

[0025] The invention is explained by examples of various combinations of components, the compositions of which are presented in Table 1.

[0026] Table 1

[0027] Name of materials Prototype Rubber compound according to the invention Option 1 Option 2 Option 3 Natural rubber RSS-20 80,0 - - - Styrene butadiene rubber (SBR 1500) 20,0 - - - Natural rubber RSS-1 - 80,0 70,0 65,0 Chloroprene rubber mercaptan regulation CAS 9010-98-4 - 20,0 30,0 35,0 Paraffin oil 19,0 - - - Zinc oxide 5,0 5,0 5,0 5,0 Magnesium oxide - 2,0 2,0 2,0 Sulfur - 2,0 2,5 2,4 N-cyclohexylbenzothiazole-2-sulfenamide 0,6 3,0 3,0 3,0 Stearic acid 2,0 2,0 2,0 2,0 N-Isopropyl-N'-Phenyl-p-Phenylenediamine 1,0 2,0 2,0 2,0 2,2,4-trimethyl-1,2-dihydroquinoline - 1,0 1,0 1,0 Protective wax 1,0 1,0 1,0 Carbon black P-514 65,0 40,0 25,0 40,0 Silica filler with a specific surface area of ​​175 - 5,0 15,0 15,0 Hexamethoxymethylmelamine - 3,0 3,0 3,0 Resorcinol formaldehyde resin - 2,0 2,0 2,0

[0028] Comparative technical characteristics of the prototype rubber compound and variants of the proposed rubber compound are presented in Table 2.

[0029] Table 2

[0030] Name of indicators Prototype Rubber compound according to the invention Test methods Option 1 Option 2 Option 3 Conditional strength, MPa 16,0 17,2 17,0 18,5 GOST 270-75 Relative elongation, % 550 330 450 400 GOST 270-75 Hardness, Shore A, conventional unit. 58 65 67 66 GOST 263-75 The bond strength of rubber to steel 3 at break, MPa 4,5 6,6 7,1 8,1 GOST 209-75 method B Resistance to ultraviolet aging: static tensile deformation of samples 20%, temperature (40±2) °C, irradiance 0.55 W / m2 at a wavelength of 340 nm, total time 72 hours (with cycles of “1 hour of darkening – 2 hours of light radiation”) Presence of cracks after a specified aging period upon visual inspection No cracks after a specified aging period upon visual inspection No cracks after a specified aging period upon visual inspection No cracks after a specified aging period upon visual inspection -

[0031] Analysis of the data in Table 1 shows that the proposed rubber compound formulation has better results in terms of key characteristics and indicators compared to the prototype: strength, relative elongation, strength of the rubber bond to steel 3 at breakaway, resistance to ultraviolet aging.