Sidewall rubber composition for improving tire appearance, preparation method thereof, and tire

Abstract

The present application belongs to the field of rubber technology, and in particular relates to a sidewall rubber composition for improving the appearance of a tire, a preparation method thereof, and a tire; the sidewall rubber composition for improving the appearance of a tire provided in the present application can slow down the migration of antioxidants and protective wax to the sidewall surface of the tire, thereby solving the technical problem in the prior art that antioxidants and paraffin wax easily migrate to the sidewall surface of the tire.

Description

Technical Field

[0001] The present application belongs to the field of rubber technology, and in particular relates to a sidewall rubber composition for improving the appearance of a tire, a preparation method thereof, and a tire. Background Art

[0002] With the improvement of living standards, people's pursuit of vehicle tires is not limited to tire performance, but also requires the appearance of the tires to meet the requirements.

[0003] At present, the tire sidewall formula mainly consists of rubber compositions, reinforcing agents such as carbon black, vulcanizing agents such as sulfur, and anti-aging agents such as antioxidants and protective waxes; among them, the rubber composition includes natural rubber and butadiene rubber. However, when rubber compositions such as natural rubber and butadiene rubber are used together with anti-aging agents such as antioxidants and protective waxes, as time goes by, the antioxidants and protective waxes tend to migrate outward to the tire sidewall surface, and even migrate to the tire tread, resulting in discoloration of the tire sidewall and tread, affecting the appearance of the tire. Summary of the invention

[0004] In view of this, the present application provides a sidewall rubber composition for improving the appearance of a tire, a preparation method thereof, and a tire, which are used to solve the technical problem in the prior art that antioxidants and protective waxes easily migrate outward to the sidewall surface of the tire.

[0005] The first aspect of the present application provides a sidewall rubber composition for improving the appearance of a tire, wherein the sidewall rubber composition comprises, in parts by mass, 5 to 20 parts of syndiotactic polybutadiene resin, 30 to 110 parts by mass of a rubber composition, 43 to 56 parts by mass of a reinforcing agent, 0.5 to 2 parts by mass of a vulcanizing agent, 1.5 to 3.5 parts by mass of an anti-aging agent, and 10 to 22 parts by mass of an auxiliary agent;

[0006] The rubber composition comprises natural rubber and chloroprene rubber;

[0007] The anti-aging agent includes antioxidant and protective wax.

[0008] Preferably, the rubber composition comprises 10 to 30 parts by mass of natural rubber and 20 to 80 parts by mass of chloroprene rubber;

[0009] The anti-aging agent comprises 1.5 to 2.5 parts by weight of an antioxidant and 0.1 to 1 part by weight of a protective wax.

[0010] Preferably, the mass ratio of the OD type antioxidant to the DAPD type antioxidant in the antioxidant is 0-1.5:0-1.5.

[0011] Preferably, the reinforcing agent includes 8 to 16 parts by mass of white carbon black and 35 to 40 parts by mass of carbon black.

[0012] Preferably, the vulcanizing agent includes 0.5 to 2 parts by mass of sulfur.

[0013] Preferably, the auxiliary agent includes 0.8-1.6 parts by mass of a silane coupling agent, 4.5-5.5 parts by mass of zinc oxide, 1-2 parts by mass of stearic acid, 2-5 parts by mass of magnesium oxide, 2-6 parts by mass of a leveling agent, and 0.2-1.8 parts by mass of an accelerator.

[0014] Preferably, the natural rubber includes SMR20 natural rubber.

[0015] Preferably, the chloroprene rubber includes CR121 type chloroprene rubber and CR122 type chloroprene rubber.

[0016] Preferably, the syndiotactic polybutadiene resin has a crystallinity of 36% and a melting point of 126°C.

[0017] Preferably, the carbon black comprises N330 type carbon black, and the white carbon black comprises fumed silica A110 type.

[0018] Preferably, the accelerator is a CZ type accelerator.

[0019] Preferably, the protective wax includes FYT-502 protective wax.

[0020] Preferably, the silane coupling agent includes Si-69L type silane coupling agent.

[0021] Preferably, the homogenizer comprises a 40MS type homogenizer.

[0022] The second aspect of the present application provides a method for preparing a sidewall rubber composition for improving the appearance of a tire, the preparation method comprising the steps of:

[0023] Step S1, putting natural rubber, chloroprene rubber, syndiotactic polybutadiene resin, magnesium oxide, stearic acid, antioxidant, protective wax, homogenizer, carbon black, white carbon black, and silane coupling agent into an internal mixer for mixing, pressing a top bolt until the temperature of the rubber material reaches 120° C. to discharge the rubber, and obtain a masterbatch;

[0024] Step S2, putting a section of masterbatch, accelerator, sulfur and zinc oxide into an internal mixer for vulcanization, pressing the top bolt until the temperature of the rubber material reaches 105°C and then discharging the rubber.

[0025] Preferably, in step S1, the mixing rotor speed is 40 r / min, and the push bolt pressure is 5.0 N / cm 2 .

[0026] Preferably, in step S2, the mixing rotor speed is 20 r / min, and the push bolt pressure is 5.0 N / cm 2 .

[0027] A third aspect of the present application provides a tire, comprising a carcass, a tread, a bead, and a sidewall prepared from the above-mentioned sidewall rubber composition.

[0028] In summary, the present application provides a sidewall rubber composition for improving the appearance of a tire, a preparation method thereof, and a tire, the sidewall rubber composition comprising 5 to 20 syndiotactic polybutadiene resins, 30 to 110 parts by mass of a rubber composition, 43 to 56 parts by mass of a reinforcing agent, 0.5 to 2 parts by mass of a vulcanizing agent, 1.5 to 3.5 parts by mass of an anti-aging agent, and 10 to 22 parts by mass of an additive; wherein, 30 to 110 parts by mass of the rubber composition comprises natural rubber and chloroprene rubber, and 1.5 to 3.5 parts by mass of the anti-aging agent comprises an antioxidant and a protective wax, the two are used together to prepare a tire sidewall, and the tire is formed into a tire with a tire carcass, a tread, and a tire bead. After the tire is subjected to a high-speed and endurance test and stored for three months, the tire and the sidewall do not show any color change, which indicates that the sidewall rubber composition provided by the present application slows down the migration of the antioxidant and the protective wax to the tire sidewall surface, and the sidewall rubber composition for improving the appearance of the tire provided by the present application solves the technical problem in the prior art that antioxidants and paraffin wax easily migrate to the tire sidewall surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 A real picture of a tire composed of a sidewall rubber composition, a carcass, a tread and a bead provided in Example 2 of the present application;

[0031] Figure 2 A real picture of a tire composed of a sidewall rubber composition, a carcass, a tread and a bead provided in Comparative Example 1 of the present application;

[0032] Figure 3 for Figure 1 Black and white comparison of the color image shown;

[0033] Figure 4 for Figure 2 Black and white comparison of the color image shown. DETAILED DESCRIPTION

[0034] The present application provides a sidewall rubber composition for improving the appearance of a tire, a preparation method thereof, and a tire, which are used to solve the technical problem in the prior art that antioxidants and protective waxes easily migrate outward to the sidewall surface of the tire.

[0035] The technical solution of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0036] Example 1

[0037] Example 1 of the present application provides a sidewall rubber composition for improving the appearance of a tire, wherein the components of the sidewall rubber composition include syndiotactic polybutadiene resin, 30 to 110 parts by mass of a rubber composition, 43 to 56 parts by mass of a reinforcing agent, 0.5 to 2 parts by mass of a vulcanizing agent, 1.5 to 3.5 parts by mass of an antioxidant, and 0.8 to 1.6 parts by mass of a silane coupling agent, 4.5 to 5.5 parts by mass of zinc oxide, 1 to 2 parts by mass of stearic acid, 2 to 5 parts by mass of magnesium oxide, 2 to 6 parts by mass of a leveling agent, and 0.2 to 1.8 parts by mass of an accelerator and other additives; the sidewall rubber composition composed above is combined with a tire carcass, tread, and tire bead to form a tire, and after the tire is subjected to high-speed and endurance tests and stored for three months, the tire and the sidewall do not show any color change, which indicates that the sidewall rubber composition provided by the present application slows down the outward migration of the antioxidant and protective wax to the sidewall surface of the tire.

[0038] The chloroprene rubber component in the sidewall rubber composition is selected from the products CR1211 and CR1212 of Shanxi Huochang Changhua Synthetic Rubber Co., Ltd.; the chloroprene rubber has good mechanical properties, and as a component of the sidewall rubber composition, it can maintain the mechanical properties of the sidewall rubber such as hardness, tensile strength and elongation at break.

[0039] The isomeric polybutadiene resin in the sidewall rubber composition can maintain the hardness and modulus of the sidewall rubber, reduce heat generation, significantly improve the flex crack resistance of the rubber composition, and improve the processing performance of the rubber composition against roller sticking.

[0040] Example 2

[0041] Example 2 of the present application provides a method for preparing the sidewall rubber composition for improving the tire appearance described in Example 1, and the preparation method includes one-stage mixing and two-stage mixing.

[0042] The first-stage mixing preparation includes putting 20 parts by mass of natural rubber, 70 parts by mass of CR121 chloroprene rubber, 10 parts by mass of syndiotactic polybutadiene resin, 3 parts by mass of magnesium oxide, 1 part by mass of stearic acid, 1 part by mass of OD type antioxidant, 1 part by mass of DAPD type antioxidant, 1 part by mass of protective wax, and 6 parts by mass of homogenizer into a mixing chamber, setting the rotor speed to 40 r / min, and setting the upper push bolt pressure to 5.0 N / cm 2After pressing for 25 seconds, the plug is lifted and 40 parts by mass of carbon black N330 and 10 parts by mass of white carbon black are added. After pressing for 40 seconds, 1 part by mass of silane coupling agent is added. The plug is pressed again until the temperature of the rubber material reaches 120°C to discharge the rubber. When the discharged rubber is cooled to below 45°C through an extruder, the laminate is collected to obtain a masterbatch.

[0043] The two-stage mixing includes drying a masterbatch for 4 hours, and then putting it into an internal mixer together with 0.4 parts by mass of accelerator, 0.8 parts by mass of sulfur and 5 parts by mass of zinc oxide. The speed of the internal mixer is set to 20r / min, and the upper bolt is pressurized to 5N / cm 2 , press to 45 seconds, lift the bolt and keep still for 5 seconds, and then press to 105℃ to discharge the rubber. The discharged rubber is further re-refined in an open mixing mill and then the sheets are cooled to below 45℃ and the stacked sheets are collected to obtain the final rubber composition.

[0044] Example 3

[0045] Example 3 of the present application provides a method for preparing the sidewall rubber composition for improving the tire appearance described in Example 1, and the preparation method includes one-stage mixing and two-stage mixing.

[0046] The first-stage mixing preparation includes putting 20 parts by mass of natural rubber, 50 parts by mass of CR121 chloroprene rubber, 25 parts by mass of CR122 chloroprene rubber, 5 parts by mass of syndiotactic polybutadiene resin, 10 parts by mass of magnesium oxide, 1 part by mass of stearic acid, 1 part by mass of OD type antioxidant, 1 part by mass of DAPD type antioxidant, 1 part by mass of protective wax, and 6 parts by mass of homogenizer into a mixing chamber, setting the rotor speed to 40 r / min, and setting the upper bolt pressure to 5.0 N / cm 2 After pressing for 25 seconds, the plug is lifted and 45 parts by mass of carbon black N330 and 10 parts by mass of white carbon black are added. After pressing for 40 seconds, 1 part by mass of silane coupling agent is added. The plug is pressed again until the temperature of the rubber material reaches 120°C to discharge the rubber. When the discharged rubber is cooled to below 45°C through an extruder, the laminate is collected to obtain a masterbatch.

[0047] The two-stage mixing includes drying a masterbatch for 4 hours, and then putting it into an internal mixer together with 0.4 parts by mass of accelerator, 0.8 parts by mass of sulfur and 5 parts by mass of zinc oxide. The speed of the internal mixer is set to 20r / min, and the upper bolt is pressurized to 5N / cm 2 , press to 45 seconds, lift the bolt and keep still for 5 seconds, and then press to 105℃ to discharge the rubber. The discharged rubber is further re-refined in an open mixing mill and then the sheets are cooled to below 45℃ and the stacked sheets are collected to obtain the final rubber composition.

[0048] Comparative Example 1

[0049] Comparative Example 1 of the present application provides a method for preparing a sidewall rubber composition, which includes one-stage mixing and two-stage mixing.

[0050] The first-stage mixing preparation includes putting 45 parts by mass of natural rubber, 55 parts by mass of butadiene rubber, 6 parts by mass of naphthenic oil, 2 parts by mass of stearic acid, 3 parts by mass of 4020 antioxidant, 1.8 parts by mass of RD antioxidant, and 2 parts by mass of protective wax into the mixing chamber, setting the rotor speed to 40r / min, and setting the upper bolt pressure to 5.0N / cm 2 After pressing for 25 seconds, lift the plug and add 52 parts by mass of carbon black N330 and press for 40 seconds, then press the plug again until the temperature of the rubber compound reaches 120°C to discharge the rubber, and collect the laminated rubber when the discharged rubber is cooled to below 45°C through the extruder to obtain a masterbatch;

[0051] The two-stage mixing includes drying a masterbatch for 4 hours, and then putting it into an internal mixer together with 0.9 parts by mass of accelerator, 1.8 parts by mass of sulfur, and 3.5 parts by mass of zinc oxide. The internal mixer speed is set to 20r / min, and the upper bolt is pressurized to 5N / cm 2 , press to 45 seconds, lift the bolt and keep still for 5 seconds, and then press to 105℃ to discharge the rubber. The discharged rubber is further re-refined in an open mixing mill and then the sheets are cooled to below 45℃ and the stacked sheets are collected to obtain the final rubber composition.

[0052] Example 4

[0053] Embodiment 4 of the present application also provides a tire, which comprises a carcass, a tread, a bead and the sidewall described in Embodiment 2.

[0054] Among them, the tire preparation process is a conventional process and will not be described here.

[0055] Test Example 1

[0056] This test example is used to test the performance of the tire formed by the sidewall rubber composition provided in Example 2 and Comparative Example 1 and the carcass, tread and bead. The test includes first subjecting the tire to a high-speed and endurance test, and then performing an appearance comparison after storing the tire for three months. The appearance comparison results are shown in FIG. Figure 2 and 1 As shown, from Figure 1 It can be seen that in the tire composed of the sidewall, carcass, tread and bead provided in Comparative Example 1, after three months, the antioxidant and anti-wax agent obviously migrated from the inside of the tire to the tire surface, causing the tire to change color and affecting the appearance of the tire, while in the tire composed of the sidewall, carcass, tread and bead provided in Example 2, after three months, the appearance of the tire had almost no change, indicating that the antioxidant and anti-wax agent in the sidewall provided in Example 2 had almost no outward migration, and the tire appearance could be maintained for a long time. Compared with the tire composed of the sidewall rubber composition, carcass, tread and bead provided in Comparative Example 1, the sidewall rubber composition provided in Example 2 can improve the appearance of the tire.

[0057] Test Example 2

[0058] This Test Example 2 is used to test the mechanical properties of the sidewall rubber compositions provided by Examples 2-3 and Comparative Example 1, wherein the test items, test standards and test results are shown in Table 1.

[0059]

[0060] Table 1

[0061] It can be seen from Table 1 that the mechanical properties of the sidewall rubber compositions provided in Examples 2-3 of the present application are similar to those of the sidewall rubber compositions provided in Comparative Example 1, and the sidewall rubber composition provided in Comparative Example 1 is a commonly used sidewall rubber composition on the market. This shows that the mechanical properties of the sidewall rubber compositions provided in Examples 2-3 of the present application are close to those of the commonly used sidewall rubber compositions on the market, and can meet the mechanical property requirements of the sidewall rubber compositions.

[0062] In summary, it can be seen from Tests 1 and 2 of the present application that the sidewall rubber composition provided in Examples 2 and 3 of the present application, which uses natural rubber and chloroprene rubber, antioxidants and protective wax, can not only meet the mechanical property requirements of commercially available sidewall rubber compositions, but also slow down the outward migration of antioxidants and anti-wax components in the sidewall, thereby improving the appearance of the tire.

[0063] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A sidewall rubber composition for improving tire appearance, characterized in that: Calculated by weight, the sidewall rubber composition includes 20 parts by weight of natural rubber, 70 parts by weight of CR121 type chloroprene rubber, 10 parts by weight of syndiotactic polybutadiene resin, 43 to 56 parts by weight of reinforcing agent, 0.5 to 2 parts by weight of sulfur, 1.5 to 3.5 parts by weight of anti-aging agent and 10 to 22 parts by weight of auxiliary agent; The anti-aging agent includes an antioxidant and a protective wax; The antioxidant includes OD type antioxidant and DAPD type antioxidant.

2. A sidewall rubber composition for improving tire appearance according to claim 1, characterized in that: Calculated by weight, the anti-aging agent includes 1.5 to 2.5 parts by weight of antioxidant and 0.1 to 1 part by weight of protective wax.

3. The sidewall rubber composition for improving tire appearance according to claim 1, characterized in that: The mass ratio of the OD type antioxidant to the DAPD type antioxidant in the antioxidant is 0-1.5:0-1.

5.

4. The sidewall rubber composition for improving tire appearance according to claim 1, characterized in that: The auxiliary agent comprises 0.8-1.6 parts by mass of a silane coupling agent, 4.5-5.5 parts by mass of zinc oxide, 1-2 parts by mass of stearic acid, 2-5 parts by mass of magnesium oxide, 2-6 parts by mass of a homogenizing agent, and 0.2-1.8 parts by mass of an accelerator.

5. A sidewall rubber composition for improving tire appearance according to claim 4, characterized in that: The reinforcing agent includes 8 to 16 parts by mass of white carbon black and 35 to 40 parts by mass of carbon black.

6. The method for preparing a sidewall rubber composition for improving tire appearance according to claim 5, characterized in that: The preparation method comprises the steps of: Step S1, putting natural rubber, chloroprene rubber, syndiotactic polybutadiene resin, magnesium oxide, stearic acid, antioxidant, protective wax, homogenizer, carbon black, white carbon black, and silane coupling agent into an internal mixer for mixing, pressing a top bolt until the temperature of the rubber material reaches 120° C. to discharge the rubber, and obtain a masterbatch; Step S2, putting a section of masterbatch, accelerator, sulfur and zinc oxide into an internal mixer for vulcanization, pressing the top bolt until the temperature of the rubber material reaches 105°C and then discharging the rubber.

7. The method for preparing a sidewall rubber composition for improving tire appearance according to claim 6, characterized in that: In step S1, the mixing rotor speed is 40r / min, and the push bolt pressure is 5.0N / cm 2 .

8. The method for preparing a sidewall rubber composition for improving tire appearance according to claim 6, characterized in that: In step S2, the mixing rotor speed is 20r / min, and the push bolt pressure is 5.0N / cm 2 .

9. A tire, characterized in that: The invention comprises a carcass, a tread, a bead and a sidewall rubber composition prepared by the preparation method according to any one of claims 6 to 8.

Images