Anti-discoloration rubber composition for colored tires and preparation method thereof

Abstract

The present application relates to the technical field of colored tire rubber, and specifically discloses an anti-discoloration rubber composition for colored tires and its preparation method. An anti-discoloration rubber composition for colored tires is prepared by first preparing modified colored silica, then using solution-polymerized styrene-butadiene rubber, natural rubber, and EPDM as the rubber matrix, adding modified colored silica for coloring and reinforcement, and then adding polydicyclopentadiene resin, titanium dioxide, YDH-151 silane coupling agent, zinc oxide, stearic acid, sulfur and TBBS accelerator, protective wax, AFS / LG antioxidant, antistatic agent and other auxiliary agents to prepare the anti-discoloration rubber composition for colored tires. The anti-discoloration rubber composition for colored tires prepared in this application has the advantages of stable color, aging resistance, good tensile strength, strong wear resistance, and strong weather resistance.

Description

Technical Field

[0001] The present application relates to the technical field of colored tire rubber, and more specifically, to an anti-discoloration rubber composition for colored tires and a preparation method thereof. Background Art

[0002] Traditional tires are mostly black, which makes it difficult to meet users' demand for diverse colors. Therefore, many tire manufacturers have launched colored tires, which have attracted considerable market attention. Colored tires have changed the traditional black color trend and made tires more fashionable and personalized.

[0003] At present, there are three main production processes for colored tires: (1) spray painting process, which uses laser to spray colored paint on the surface of the vulcanized tire, but the color of the tire produced by this process disappears quickly after wear; (2) glue process, which is to apply colored film to the tire embryo and then vulcanize it, but this process is limited to the side of the tire; (3) full color process, which is to produce colorful tires by adding colorants to the tire rubber, but this process has the following problems: carbon black cannot be used, the coloring filler affects its durability, white carbon black is easy to agglomerate, processing is difficult, and the color changes due to aging resistance migration.

[0004] Therefore, there is still a need to further develop anti-discoloration rubber compositions for colored tires. Summary of the Invention

[0005] In order to further improve the anti-discoloration performance of colored tires while ensuring that the basic performance of the tires is not affected, the present application provides an anti-discoloration rubber composition for colored tires and a preparation method thereof.

[0006] In a first aspect, the present application provides an anti-discoloration rubber composition for colored tires, which adopts the following technical solution:

[0007] The invention discloses an anti-discoloration rubber composition for colored tires, comprising the following components in parts by weight: 20-30 parts of solution-polymerized styrene-butadiene rubber, 50-60 parts of natural rubber, 10-30 parts of EPDM rubber, 40-60 parts of modified colored silica, 12-15 parts of titanium dioxide, 3-5 parts of polydicyclopentadiene resin, 8-10 parts of YDH-151 silane coupling agent, 3-5 parts of zinc oxide, 2-3 parts of stearic acid, 1-2 parts of sulfur, 1-2 parts of TBBS accelerator, 2.5-4.5 parts of protective wax, 3-5 parts of AFS / LG antioxidant, and 1-2 parts of antistatic agent.

[0008] By adopting the above technical scheme, solution-polymerized styrene-butadiene rubber, natural rubber, and EPDM rubber are used as the rubber matrix, modified colored silica is added for coloring and reinforcement, and auxiliary agents such as polydicyclopentadiene resin, titanium dioxide, YDH-151 silane coupling agent, zinc oxide, stearic acid, sulfur and TBBS accelerator, protective wax, AFS / LG antioxidant, antistatic agent, etc. are added to prepare an anti-discoloration rubber composition for colored tires with excellent heat-oxidative aging resistance, ozone aging resistance, tensile properties, wear resistance, weather resistance and color stability.

[0009] Preferably, the modified colored silica is prepared by the following steps: S1, mixing a sulfuric acid solution and (3-mercaptopropyl)triethoxysilane, stirring and activating for 10-15 minutes; S2, slowly adding a water glass solution to S1 for reaction, and when the pH value of the system is 3-4, adding a colorant dispersion, and then adding the remaining water glass solution, and continuing to stir until the reaction system is converted into a gel; S3, pressing the formed gel, washing with water, drying, and crushing to obtain colored silica; S4, dispersing the colored silica in n-hexane by ultrasonic dispersion at 50-60°C to obtain a colored silica dispersion; at the same time, stirring and dissolving a homopolymer of 2-methyl-1,3-butadiene in n-hexane at 50-60°C to obtain a homopolymer solution; then mixing the two, stirring for 4-6 hours, adding a photoinitiator BDK, continuing to stir for 1-1.5 hours and then stopping, then volatilizing the solvent, and irradiating with an ultraviolet lamp for 30-40 minutes to obtain the modified colored silica.

[0010] By adopting the above technical solution, a colorant is added during the process of preparing white carbon black using sulfuric acid and water glass to improve the adsorption capacity of white carbon black for the colorant, and (3-mercaptopropyl)triethoxysilane is used to hydrophobically modify and disperse the generated white carbon black. At the same time, the reaction between the homopolymer of 2-methyl-1,3-butadiene and the mercapto group is utilized to wrap the white carbon black, thereby enhancing the stability of the colorant and preventing the color migration and discoloration caused by the antioxidant and protective wax to the colorant. Finally, the modified colored white carbon black is added to the rubber solution, and the white carbon black and rubber are connected through the homopolymer of 2-methyl-1,3-butadiene, thereby replacing carbon black to achieve a reinforcing effect on the rubber and enhance its mechanical properties.

[0011] Preferably, the concentration of the sulfuric acid solution is 0.4-0.5 mol / L, the modulus of the water glass solution is 3-3.5, and the concentration is 0.4-0.5 mol / L; and the concentration of the colorant dispersion is 0.3-0.5 g / L.

[0012] By adopting the above technical solution, the raw materials at this concentration can be used to form white carbon black powder with a smaller particle size and a larger specific surface area.

[0013] Preferably, the colorant in the colorant dispersion is an organic pigment, and the colorant dispersion further comprises a pigment synergist.

[0014] The colorant includes but is not limited to phthalocyanine blue, color red 144, and pigment yellow 183.

[0015] By adopting the above technical solution and using organic pigments as pigment colorants, the tinting strength between the organic pigments and the formed white carbon black can be enhanced.

[0016] Preferably, the usage ratio of the sulfuric acid solution, (3-mercaptopropyl)triethoxysilane, water glass solution, and colorant dispersion is (3-3.5) L: (0.2-0.4) g: (3-4) L: (1.5-2) L.

[0017] By adopting the above technical solution, the colored white carbon black prepared under this ratio has good dispersibility and stable coloring.

[0018] Preferably, the volume ratio of the colored silica dispersion to the homopolymer solution is (1-1.2):1.

[0019] Preferably, the concentration of the colored silica dispersion is 0.1-0.2 kg / L, and the concentration of the homopolymer solution is 0.05-0.08 g / L.

[0020] Preferably, the added amount of the photoinitiator BDK is 0.2-0.5% of the mass fraction of colored white carbon black.

[0021] By adopting the above technical solution, the homopolymer of 2-methyl-1,3-butadiene is reacted with thiol by an initiator to wrap the white carbon black and enhance the stability of the colorant.

[0022] In a second aspect, the present application provides a method for preparing the aforementioned anti-discoloration rubber composition for colored tires.

[0023] A method for preparing an anti-discoloration rubber composition for colored tires comprises the following steps: (1) mixing solution-polymerized styrene-butadiene rubber, natural rubber, ethylene propylene diene monomer rubber and cyclohexane to prepare a rubber solution; (2) adding modified colored silica to the rubber solution, mixing and dispersing the mixture uniformly, stirring and flocculating, and drying the solidified substance to obtain a masterbatch; (3) adding a mixture of the masterbatch, stearic acid, polydicyclopentadiene resin, titanium dioxide, zinc oxide, protective wax, AFS / LG antioxidant, antistatic agent and YDH-151 silane coupling agent to an internal mixer for mixing, and then adding sulfur and TBBS accelerator to an open mixer for mixing to obtain a rubber mixture; and (4) allowing the rubber mixture to stand for 7-8 hours and vulcanizing it on a flat vulcanizer to obtain the anti-discoloration rubber composition for colored tires.

[0024] The vulcanization conditions are a temperature of 145-150°C, a pressure of 8-10 MPa, and a vulcanization time of 25-30 minutes.

[0025] By adopting the above technical solution, the modified colored silica is first mixed with the rubber solution, which can enhance the dispersibility of the modified colored silica in the rubber.

[0026] In summary, this application has the following beneficial effects:

[0027] 1. This application adopts solution-polymerized styrene-butadiene rubber, natural rubber, and EPDM rubber as the rubber matrix, and coloring and reinforcing are performed by adding modified colored silica. By adding auxiliary agents such as polydicyclopentadiene resin, titanium dioxide, YDH-151 silane coupling agent, zinc oxide, stearic acid, sulfur and TBBS accelerator, protective wax, AFS / LG antioxidant, antistatic agent, etc., an anti-discoloration rubber composition for colored tires with excellent heat-oxidative aging resistance, ozone aging resistance, tensile properties, wear resistance, weather resistance and color stability is prepared.

[0028] 2. In the present application, the adsorption capacity of silica for the colorant is improved by adding a colorant during the preparation of silica using sulfuric acid and water glass, and (3-mercaptopropyl) triethoxysilane is used to hydrophobically modify and disperse the generated silica. At the same time, the reaction between the homopolymer of 2-methyl-1,3-butadiene and the mercapto group is utilized to wrap the silica, enhance the stability of the colorant, and prevent the color migration and discoloration caused by the antioxidant and protective wax to the colorant. Finally, the modified colored silica is added to the rubber solution, and the silica and rubber are connected through the homopolymer of 2-methyl-1,3-butadiene, thereby replacing carbon black to achieve a reinforcing effect on the rubber and enhance its mechanical properties.

[0029] 3. The anti-discoloration rubber composition prepared by the preparation method of the present application has stable color, aging resistance, good tensile properties, strong wear resistance, and excellent weather resistance, and can be used to prepare colored tires. DETAILED DESCRIPTION

[0030] The present application is further described in detail below with reference to the embodiments.

[0031] Unless otherwise specified, the raw materials used in the examples and comparative examples of the present application are all commercially available.

[0032] Example

[0033] Example 1

[0034] The anti-discoloration rubber composition for colored tires comprises the following components in parts by weight: 25 parts of solution-polymerized styrene-butadiene rubber, 55 parts of natural rubber, 20 parts of EPDM rubber, 55 parts of modified colored silica, 13 parts of titanium dioxide, 4 parts of polydicyclopentadiene resin, 9 parts of YDH-151 silane coupling agent, 4 parts of zinc oxide, 3 parts of stearic acid, 2 parts of sulfur and 2 parts of TBBS accelerator, 3 parts of protective wax, 4 parts of AFS / LG antioxidant, and 2 parts of HDC-305 antistatic agent.

[0035] The modified colored silica is prepared by the following steps:

[0036] S1, mix 2 L of 0.5 mol / L sulfuric acid solution and 0.3 g of (3-mercaptopropyl)triethoxysilane, and stir to activate for 15 min;

[0037] S2, slowly adding 3 L of a water glass solution with a modulus of 3.2 and a concentration of 0.5 mol / L to S1 for reaction. When the pH value of the system is 4, adding 2 L of a colorant dispersion with a concentration of 0.3 g / L, and then adding the remaining water glass solution, and continuing stirring until the reaction system is converted into a gel; the colorant in the colorant dispersion is phthalocyanine blue, and the colorant dispersion also contains a pigment synergist (purchased from Lubrizol).

[0038] S3, filtering the formed gel, washing with water, drying, and crushing to obtain colored white carbon black;

[0039] S4, dispersing colored silica in n-hexane by ultrasonic dispersion at 60°C to prepare a colored silica dispersion with a concentration of 0.1 kg / L; at the same time, dissolving a homopolymer of 2-methyl-1,3-butadiene in n-hexane by stirring at 60°C to prepare a homopolymer solution with a concentration of 0.05 g / L; then mixing the two in a volume ratio of 1:1, stirring for 5 hours, adding a photoinitiator BDK with a mass fraction of 0.3% of colored silica, continuing stirring for 1 minute and then stopping, then evaporating the solvent, and irradiating with a 365nm ultraviolet lamp for 30 minutes to obtain a modified colored silica.

[0040] The method for preparing the anti-discoloration rubber composition for colored tires comprises the following steps:

[0041] (1) mixing solution-polymerized styrene-butadiene rubber, natural rubber, EPDM rubber and cyclohexane (10 times the total mass of the rubber) to prepare a rubber solution;

[0042] (2) adding the modified colored silica to the rubber solution, mixing and dispersing the mixture uniformly, stirring and flocculating the mixture, and drying the coagulated solid to obtain a masterbatch;

[0043] (3) adding a mixture of masterbatch, stearic acid, polydicyclopentadiene resin, titanium dioxide, zinc oxide, protective wax, AFS / LG antioxidant, HDC-305 antistatic agent and YDH-151 silane coupling agent to an internal mixer for mixing, and then adding sulfur and TBBS accelerator to an open mixer for mixing to obtain a rubber compound;

[0044] (4) The rubber mixture was allowed to stand for 8 hours and then vulcanized on a flat vulcanizer at 148° C. and 9 MPa for 28 minutes to obtain an anti-discoloration rubber composition for colored tires.

[0045] Example 2

[0046] The anti-discoloration rubber composition for colored tires comprises the following components in parts by weight: 30 parts of solution-polymerized styrene-butadiene rubber, 60 parts of natural rubber, 10 parts of EPDM rubber, 40 parts of modified colored silica, 12 parts of titanium dioxide, 3 parts of polydicyclopentadiene resin, 8 parts of YDH-151 silane coupling agent, 3 parts of zinc oxide, 2 parts of stearic acid, 1 part of sulfur and 1 part of TBBS accelerator, 2.5 parts of protective wax, 3 parts of AFS / LG antioxidant, and 1 part of HDC-305 antistatic agent.

[0047] The modified colored silica is prepared by the following steps:

[0048] S1, mix 3 L of 0.4 mol / L sulfuric acid solution and 0.2 g of (3-mercaptopropyl)triethoxysilane, and stir to activate for 10 min;

[0049] S2, slowly adding 3 L of a water glass solution with a modulus of 3 and a concentration of 0.4 mol / L to S1 for reaction, when the pH value of the system is 3, adding 1.5 L of a colorant dispersion with a concentration of 0.3 g / L, and then adding the remaining water glass solution, and continuing to stir until the reaction system is converted into a gel; the colorant in the colorant dispersion is Color Red 144, and the colorant dispersion also contains a pigment synergist (purchased from Lubrizol).

[0050] S3, filtering the formed gel, washing with water, drying, and crushing to obtain colored white carbon black;

[0051] S4, dispersing colored silica in n-hexane by ultrasonic dispersion at 50°C to prepare a colored silica dispersion with a concentration of 0.1 kg / L; at the same time, dissolving a homopolymer of 2-methyl-1,3-butadiene in n-hexane by stirring at 50°C to prepare a homopolymer solution with a concentration of 0.05 g / L; then mixing the two in a volume ratio of 1.2:1, stirring for 4 hours, adding a photoinitiator BDK with a mass fraction of colored silica of 0.2%, continuing stirring for 1 hour and then stopping, then evaporating the solvent, and irradiating with a 365nm ultraviolet lamp for 30 minutes to obtain a modified colored silica.

[0052] The method for preparing the anti-discoloration rubber composition for colored tires comprises the following steps:

[0053] (2) mixing solution-polymerized styrene-butadiene rubber, natural rubber, EPDM rubber and cyclohexane (11 times the total mass of the rubber) to prepare a rubber solution;

[0054] (2) adding the modified colored silica to the rubber solution, mixing and dispersing the mixture uniformly, stirring and flocculating the mixture, and drying the coagulated solid to obtain a masterbatch;

[0055] (3) adding a mixture of masterbatch, stearic acid, polydicyclopentadiene resin, titanium dioxide, zinc oxide, protective wax, AFS / LG antioxidant, HDC-305 antistatic agent and YDH-151 silane coupling agent to an internal mixer for mixing, and then adding sulfur and TBBS accelerator to an open mixer for mixing to obtain a rubber compound;

[0056] (4) The rubber mixture was allowed to stand for 7 hours and vulcanized on a flat vulcanizer at 145° C. and 8 MPa for 30 minutes to obtain an anti-discoloration rubber composition for colored tires.

[0057] Example 3

[0058] The anti-discoloration rubber composition for colored tires comprises the following components in parts by weight: 20 parts of solution-polymerized styrene-butadiene rubber, 50 parts of natural rubber, 30 parts of EPDM rubber, 60 parts of modified colored silica, 15 parts of titanium dioxide, 5 parts of polydicyclopentadiene resin, 10 parts of YDH-151 silane coupling agent, 5 parts of zinc oxide, 3 parts of stearic acid, 2 parts of sulfur and 2 parts of TBBS accelerator, 4.5 parts of protective wax, 5 parts of AFS / LG antioxidant, and 2 parts of HDC-305 antistatic agent.

[0059] The modified colored silica is prepared by the following steps:

[0060] S1, mix 3.5 L of 0.5 mol / L sulfuric acid solution and 0.4 g of (3-mercaptopropyl)triethoxysilane, and stir to activate for 15 min;

[0061] S2, slowly adding 4 L of a water glass solution with a modulus of 3.5 and a concentration of 0.5 mol / L to S1 for reaction; when the pH value of the system is 4, adding 2 L of a colorant dispersion with a concentration of 0.5 g / L, and then adding the remaining water glass solution, and continuing stirring until the reaction system is converted into a gel; the colorant in the colorant dispersion is Pigment Yellow 183, and the colorant dispersion also contains a pigment synergist (purchased from Lubrizol).

[0062] S3, filtering the formed gel, washing with water, drying, and crushing to obtain colored white carbon black;

[0063] S4, dispersing colored silica in n-hexane by ultrasonic dispersion at 55°C to prepare a colored silica dispersion with a concentration of 0.15 kg / L; at the same time, dissolving a homopolymer of 2-methyl-1,3-butadiene in n-hexane by stirring at 55°C to prepare a homopolymer solution with a concentration of 0.07 g / L; then mixing the two in a volume ratio of 1.2:1, stirring for 6 hours, adding a photoinitiator BDK with a mass fraction of colored silica of 0.5%, continuing stirring for 1.5 hours and then stopping, then evaporating the solvent, and irradiating with a 365nm ultraviolet lamp for 40 minutes to obtain a modified colored silica.

[0064] The method for preparing the anti-discoloration rubber composition for colored tires comprises the following steps:

[0065] (3) mixing solution-polymerized styrene-butadiene rubber, natural rubber, EPDM rubber and cyclohexane (12 times the total mass of the rubber) to prepare a rubber solution;

[0066] (2) adding the modified colored silica to the rubber solution, mixing and dispersing the mixture uniformly, stirring and flocculating the mixture, and drying the coagulated solid to obtain a masterbatch;

[0067] (3) adding a mixture of masterbatch, stearic acid, polydicyclopentadiene resin, titanium dioxide, zinc oxide, protective wax, AFS / LG antioxidant, HDC-305 antistatic agent and YDH-151 silane coupling agent to an internal mixer for mixing, and then adding sulfur and TBBS accelerator to an open mixer for mixing to obtain a rubber compound;

[0068] (4) The rubber mixture was allowed to stand for 8 hours and vulcanized on a flat vulcanizer at 150° C. and 10 MPa for 25 minutes to obtain an anti-discoloration rubber composition for colored tires.

[0069] Comparative Example

[0070] Comparative Example 1

[0071] The same as Example 1, except that: white carbon black (the preparation process of white carbon black is the same as that of Example 1, except that no colorant dispersion is added) is used instead of modified colored white carbon black and is directly added to (2), that is: (2) white carbon black is added to the rubber solution, mixed and dispersed uniformly, stirred and flocculated, and the coagulated solid is dried to obtain a masterbatch;

[0072] At the same time, phthalocyanine blue and (3-mercaptopropyl) triethoxysilane are directly added to (3), that is: (3) a mixture of masterbatch, stearic acid, polydicyclopentadiene resin, titanium dioxide, phthalocyanine blue, (3-mercaptopropyl) triethoxysilane, zinc oxide, protective wax, AFS / LG antioxidant, HDC-305 antistatic agent and YDH-151 silane coupling agent is added to an internal mixer for mixing, and then put on an open mixer and added with sulfur and TBBS accelerator for mixing to obtain a mixed rubber.

[0073] Comparative Example 2

[0074] The same as Example 1, except that: no AFS / LG antioxidant and protective wax are added.

[0075] Comparative Example 3

[0076] The same as Example 1, except that the preparation process of the modified colored silica does not include S4, and the homopolymer of 2-methyl-1,3-butadiene is directly added to (3).

[0077] Performance testing

[0078] 1. The anti-discoloration rubber compositions for colored tires prepared using Examples 1-3 and Comparative Examples 1-3 were subjected to the following performance tests: a. Tensile properties: tensile strength, elongation at break, 100% modulus of elongation, and 300% modulus of elongation were tested according to the GB / T528-2009 test standard; b. Wear resistance: abrasion resistance was tested according to the GB / T 42122-2022 test standard; c. Heat aging resistance: tensile modulus tested according to the GB / T3512-2014 test standard under hot air aging (100°C x 48h); d. Ozone resistance: static ozone cracking resistance tested according to the GB / T7762-2014 test standard (40°C x 72h x 50pphm x 20%); e. Weather resistance: color change was observed after three months of storage according to the GB / T3511-2001 test standard. The test results are shown in Table 1.

[0079] Table 1. Performance test results

[0080]

[0081] As can be seen from Table 1, the anti-discoloration rubber compositions for colored tires prepared in Examples 1 to 3 have the best resistance to heat and oxygen aging, ozone aging, tensile properties, wear resistance, weather resistance and color stability. In combination with Comparative Examples 1 to 3, it can be seen that a colorant is added in advance during the preparation of silica, and (3-mercaptopropyl)triethoxysilane is used to disperse silica, while a homopolymer of 2-methyl-1,3-butadiene is used to wrap silica, thereby enhancing the stability of the colorant and preventing color migration and discoloration caused by antioxidants and protective wax. At the same time, the homopolymer of 2-methyl-1,3-butadiene connects silica and rubber, which can replace carbon black to achieve a reinforcement effect on the rubber and enhance its mechanical properties.

[0082] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, and such modifications shall be protected by the patent law as long as they are within the scope of protection claimed in the present application.

Claims

1. An anti-discoloration rubber composition for colored tires, characterized in that: The composition comprises the following parts by weight: 20-30 parts of solution-polymerized styrene-butadiene rubber, 50-60 parts of natural rubber, 10-30 parts of EPDM rubber, 40-60 parts of modified colored silica, 12-15 parts of titanium dioxide, 3-5 parts of polydicyclopentadiene resin, 8-10 parts of YDH-151 silane coupling agent, 3-5 parts of zinc oxide, 2-3 parts of stearic acid, 1-2 parts of sulfur, 1-2 parts of TBBS accelerator, 2.5-4.5 parts of protective wax, 3-5 parts of AFS / LG antioxidant, and 1-2 parts of antistatic agent, wherein the solution-polymerized styrene-butadiene rubber, natural rubber, and EPDM rubber are the rubber matrix; The modified colored silica is prepared by the following steps: S1, mixing a sulfuric acid solution and (3-mercaptopropyl) triethoxysilane, stirring and activating for 10-15 minutes; S2, slowly adding a water glass solution into S1 for reaction; when the pH value of the system is 3-4, adding a colorant dispersion, then adding the remaining water glass solution, and continuing to stir until the reaction system is converted into a gel; S3, filtering the formed gel, washing with water, drying, and crushing to obtain colored silica; S4, dispersing the colored silica in n-hexane at 50-60° C. and ultrasonically dispersing the colored silica to obtain a colored silica dispersion; and simultaneously adding 2-methyl- The homopolymer of 1,3-butadiene is dissolved in n-hexane with stirring at 50-60°C to obtain a homopolymer solution; the two are then mixed, stirred for 4-6 hours, and then a photoinitiator BDK is added, and the stirring is continued for 1-1.5 hours and then stopped, and then the solvent is evaporated, and the product is irradiated with an ultraviolet lamp for 30-40 minutes to obtain a modified colored silica; the homopolymer of 2-methyl-1,3-butadiene is reacted with a thiol group by the initiator to wrap the silica and enhance the stability of the colorant; the silica and rubber are connected by the homopolymer of 2-methyl-1,3-butadiene, thereby replacing carbon black to achieve a reinforcement effect on the rubber and enhance its mechanical properties.

2. The anti-discoloration rubber composition for colored tires according to claim 1, characterized in that: The composition is composed of 25 parts of solution-polymerized styrene-butadiene rubber, 55 parts of natural rubber, 20 parts of EPDM rubber, 55 parts of modified colored silica, 13 parts of titanium dioxide, 4 parts of polydicyclopentadiene resin, 9 parts of YDH-151 silane coupling agent, 4 parts of zinc oxide, 3 parts of stearic acid, 2 parts of sulfur and 2 parts of TBBS accelerator, 3 parts of protective wax, 4 parts of AFS / LG antioxidant, and 2 parts of HDC-305 antistatic agent.

3. The anti-discoloration rubber composition for colored tires according to claim 1, characterized in that: The concentration of the sulfuric acid solution is 0.4-0.5 mol / L, the modulus of the water glass solution is 3-3.5, and the concentration is 0.4-0.5 mol / L; the concentration of the colorant dispersion is 0.3-0.5 g / L.

4. The anti-discoloration rubber composition for colored tires according to claim 3, characterized in that: The colorant in the colorant dispersion is an organic pigment, and the colorant dispersion further contains a pigment synergist.

5. The anti-discoloration rubber composition for colored tires according to claim 4, characterized in that: The usage ratio of the sulfuric acid solution, (3-mercaptopropyl)triethoxysilane, water glass solution and colorant dispersion is (3-3.5) L: (0.2-0.4) g: (3-4) L: (1.5-2) L.

6. The anti-discoloration rubber composition for colored tires according to claim 5, characterized in that: The volume ratio of the colored silica dispersion to the homopolymer solution is (1-1.2):

1.

7. The anti-discoloration rubber composition for colored tires according to claim 6, characterized in that: The concentration of the colored silica dispersion is 0.1-0.2 kg / L, and the concentration of the homopolymer solution is 0.05-0.08 g / L.

8. The anti-discoloration rubber composition for colored tires according to claim 7, characterized in that: The added amount of the photoinitiator BDK is 0.2-0.5% of the mass fraction of the colored white carbon black.

9. A method for preparing the anti-discoloration rubber composition for colored tires according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) mixing solution-polymerized styrene-butadiene rubber, natural rubber, EPDM rubber and cyclohexane to prepare a rubber solution; (2) adding modified colored silica to the rubber solution, mixing and dispersing the mixture uniformly, stirring and flocculating, and drying the solidified solid to obtain a masterbatch; (3) adding a mixture of the masterbatch, stearic acid, polydicyclopentadiene resin, titanium dioxide, zinc oxide, protective wax, AFS / LG antioxidant, antistatic agent and YDH-151 silane coupling agent to an internal mixer for mixing, and then adding sulfur and TBBS accelerator to an open mixer for mixing to obtain a rubber mixture; (4) allowing the rubber mixture to stand for 7-8 hours and vulcanizing it on a flat vulcanizer to obtain an anti-discoloration rubber composition for colored tires.

10. The method for preparing the anti-discoloration rubber composition for colored tires according to claim 9, characterized in that: The vulcanization conditions are a temperature of 145-150°C, a pressure of 8-10 MPa, and a vulcanization time of 25-30 minutes.

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