Process for preparing vinyl cage silsesquioxane modified styrene-butadiene rubber and use thereof

Abstract

Preparation method and application of vinyl cage type silsesquioxane modified butadiene styrene rubber, the invention belongs to the technical field of rubber material modification; cage type silsesquioxane modified butadiene styrene rubber is a modified polymer with organic and inorganic hybrid structure, has high glass transition temperature, heat resistance, cold resistance and excellent wet skid resistance; the vinyl cage type silsesquioxane has a Si-O-Si three-dimensional network structure, can make carbon black and white carbon black firmly adhere to the polymer matrix, reduce the frictional resistance between the tire and the ground, and has excellent wear resistance; the vinyl cage type silsesquioxane contains a large number of vinyl active groups, has good compatibility with other unsaturated rubbers, and can be organically combined with other auxiliary systems, and has good wet skid resistance and low-temperature resistance; the material can be applied in tire tread rubber to effectively improve the problems of automobile tire in low-temperature rainy and snowy weather, such as skid resistance, wear resistance and low-temperature easy tearing.

Description

Technical Field

[0001] The invention belongs to the technical field of rubber material modification, and in particular relates to the preparation of modified styrene-butadiene rubber and the application of the modified styrene-butadiene rubber in tire tread rubber. Background Art

[0002] With the rapid development of the automobile industry, family cars and cargo vehicles have become indispensable means of transportation in people's lives. Automobile tires are the most important parts of a car, and their quality directly affects the safety of drivers and passengers. Generally, automobile tires are composed of treads, sidewalls, cushion rubber, belt layers, cord layers, inner liners, and beads. The tread is the only part of the car that contacts the ground. Various performance of the car, such as driving and braking performance, anti-skid performance, wear resistance, low-temperature resistance, and operational stability, are completely achieved through the interaction between the tire and the ground. Therefore, the selection and preparation of tire tread rubber materials are extremely important, especially in rainy, snowy, and low-temperature weather conditions. The anti-skid and low-temperature resistance of the tire material are of paramount importance.

[0003] Styrene-butadiene rubber (SBR) is currently one of the primary raw materials for tire treads. However, SBR has low strength and relatively poor adhesion and elasticity, requiring the addition of highly active reinforcing agents for tire use. Reinforcing agents are typically carbon black and silica. While carbon black offers excellent reinforcement and improved wear resistance, it also results in poor wet skid resistance, high hysteresis loss, increased rolling resistance, high heat generation, and low elasticity. Increasing the amount of silica can improve wet skid resistance, but silica is difficult to disperse.

[0004] Since the promulgation of the EU tire labeling regulations, how to improve the wet grip of tire tread rubber without increasing rolling resistance has become an important issue in the design of high-performance tires. Dr. Zhang Lingyan of Double Coin Group Co., Ltd. (Tire Industry, 2013, 9 (33): 543-546) proposed that the higher the glass transition temperature (tg) of the rubber compound, the better its wet grip. In order to make the rubber compound have both excellent wet grip and low rolling resistance, this can be achieved by designing and modifying the molecular structure of the main raw materials of the rubber compound. He Hui et al. from the Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Nanjing University (Polymer Materials Science and Engineering, 2008.24 (4): 5-9) proposed to prepare functional coatings by utilizing the smooth, wear-resistant, and oxidation-resistant properties of cage-type silsesquioxane-modified polymers. Tangshan Sanyou Qi Wenling (Organic Silicone Materials, 2023, 37(2): 73~77) proposed that polysilsesquioxane itself has excellent advantages such as heat resistance, cold resistance, compatibility, and stability. Through molecular design, functionalized polysilsesquioxane can be synthesized in a targeted manner and applied in the fields of adsorption materials. Based on the various functions of silsesquioxane studied by the above personnel, the present inventors have conducted a lot of research on the application of cage-type silsesquioxane-modified styrene-butadiene rubber in automobile tire composite materials in response to the above reasons and the problems existing in styrene-butadiene rubber in tire tread rubber. It was found that vinyl cage-type silsesquioxane-modified styrene-butadiene rubber has excellent wet grip performance, wear resistance and low temperature resistance when used in tire tread rubber. Summary of the Invention

[0005] The present invention provides a method for preparing and applying vinyl cage silsesquioxane-modified styrene-butadiene rubber. The method comprises: first subjecting vinyl cage silsesquioxane to a halogenated addition reaction with a hydrogen halide, followed by graft polymerization with styrene-butadiene rubber via a Friedel-Crafts reaction in the presence of a catalyst, to obtain the modified styrene-butadiene rubber. This polymer, a modified organic-inorganic hybrid polymer, exhibits a high glass transition temperature and excellent wet grip. The vinyl cage silsesquioxane has a three-dimensional Si—O—Si network structure, which enables carbon black and white carbon black to adhere firmly to the polymer matrix, reducing frictional resistance between the tire and the ground, resulting in excellent wear resistance. The vinyl cage silsesquioxane contains a large number of vinyl reactive groups, exhibiting good compatibility with other unsaturated rubbers and can be organically combined with other additive systems to form a novel composite system. Studies have shown that it exhibits excellent wet skid resistance and low-temperature resistance. DETAILED DESCRIPTION

[0006] (1) The preparation method of the modified styrene-butadiene rubber is to firstly carry out a halogen addition reaction between vinyl cage silsesquioxane and hydrogen halide, and then carry out graft polymerization with styrene-butadiene rubber through Friedel-Crafts reaction, and the specific steps are as follows: 1) adding a certain proportion of solvent and styrene-butadiene rubber to a prefabricated mixing tank, stirring and mixing them thoroughly to prepare a styrene-butadiene rubber prefabricated liquid for use; 2) introducing nitrogen into the reactor to replace the air until the oxygen content is below 0.002%, and then adding solvent, catalyst, vinyl cage silsesquioxane in sequence, mixing them thoroughly, and then stirring the prefabricated liquid to obtain the styrene-butadiene rubber prefabricated liquid; Introduce hydrogen halide gas into the reactor, control the reactor temperature at 20°C-30°C and the ratio of the reactants, and continue the reaction for half an hour after the hydrogen halide gas is introduced; 3) increase the temperature of the reactor and control the temperature at 40°C-63°C, add the styrene-butadiene rubber preformed liquid and 1 / 2 part by mass of the catalyst to the reactor, allow to react for 1 hour, add the remaining catalyst to the reactor, continue the reaction for 3 hours, and after the reaction is completed, add a certain amount of water, wash, stand for separation, remove the solvent, and dry to obtain the modified styrene-butadiene rubber.

[0007] In step 1), in the preparation method of the modified styrene-butadiene rubber, the solvent is one or more of toluene, xylene, tetrahydrofuran, and cyclohexane, wherein the mass ratio of the solvent to the styrene-butadiene rubber is 5:1;

[0008] In step 1), the styrene-butadiene rubber is a high-binding styrene-butadiene rubber with a styrene binding degree of 40%;

[0009] In step 2), the vinyl cage silsesquioxane is one or more of tetravinyl cage silsesquioxane, hexavinyl cage silsesquioxane, octavinyl cage silsesquioxane, and decamethylene cage silsesquioxane;

[0010] In step 2), the mass ratio of the added solvent to the vinyl silsesquioxane is 5:1;

[0011] In step 2), the hydrogen halide gas is one of HBr and HCl; the amount of the hydrogen halide gas to the vinyl cage silsesquioxane is 1.01:1 (molar ratio);

[0012] In step 2), the catalyst is one or more of AICl3, FeCl3, SnCl4, and ZnCl2; the amount of the catalyst added is 0.01-0.2% of the mass of the reactants;

[0013] In step 3), the temperature of the reactor is controlled at 40°C to 63°C, preferably 55°C to 60°C.

[0014] (2) A method for preparing and applying vinyl cage silsesquioxane modified styrene-butadiene rubber, comprising the following steps:

[0015] Step 4) Mix 60-100 parts of modified styrene-butadiene rubber in an internal mixer for 30 seconds, add 10-40 parts of butadiene rubber and 15-40 parts of environmentally friendly aromatic oil in the internal mixer, mix for 180-300 seconds in the internal mixer to obtain oil-extended rubber, add tackifying resin, 5-20 parts of white carbon black, 20-50 parts of carbon black, 5-15 parts of silane coupling agent, 2-5 parts of zinc oxide, 0.5-3 parts of stearic acid, 5-15 parts of antioxidant in the internal mixer at 35-50°C, and mix for 300-360 seconds. seconds; then, 0.5-3 parts of a vulcanizing accelerator and 1-3 parts of a vulcanizing agent are added into an internal mixer and mixed for 100-180 seconds to obtain a first-stage rubber mix; the first-stage rubber mix is ​​subjected to open thinning on an open mixer for 3 times, the rubber is tapped left and right for 3 times, and the rubber is packaged 5 times. After the rubber is unrolled, the sheet is left to stand for 24 hours; the second-stage rubber mix that has been left to stand is vulcanized on a flat vulcanizer at 145°C±0.5°C and a pressure of 15 MPa to obtain a tread rubber composition composite material that is anti-skid, wear-resistant, and resistant to low temperatures.

[0016] The preparation methods of the embodiments and comparative examples are as follows:

[0017] (1) Preparation of modified styrene-butadiene rubber

[0018] Add 750 parts by weight of tetrahydrofuran solvent and 150 parts by weight of styrene-butadiene rubber with a 40% styrene content to a prefabricated mixing tank, mix thoroughly and wait for standby; introduce nitrogen into the reactor to replace the air until the oxygen content is below 0.002%, add 30 parts by weight of tetrahydrofuran into the reactor and start stirring, then add 6 parts by weight of octavinyl cage silsesquioxane and 0.006 parts by weight of aluminum chloride into the reactor, stir for 15 minutes, and then introduce hydrogen chloride gas into the reactor at a flow rate of 0.5 m³ / min. h and the reactor temperature is controlled at 25±5° C., and the amount of hydrogen chloride gas introduced is 5.74% of the total reactants. After the introduction of hydrogen chloride gas is completed, the reaction is continued for half an hour; the temperature of the reactor is increased to 50° C., 900 parts by weight of a premixed styrene-butadiene rubber prefabricated liquid and 0.78 parts by weight of aluminum trichloride are added to the reactor, and after reacting for 1 hour, 0.78 parts by weight of aluminum trichloride is added to the reactor, and the reaction is continued for 3 hours. A certain amount of deionized water is added for washing, the mixture is allowed to stand for separation, the solvent is removed, and the mixture is dried to obtain the modified styrene-butadiene rubber.

[0019] (II) Application examples of vinyl cage silsesquioxane modified styrene-butadiene rubber

[0020] Example 1: Preparation method and application of vinyl cage silsesquioxane modified styrene-butadiene rubber. The specific steps are as follows:

[0021] 80 parts by weight of the modified styrene-butadiene rubber prepared above were mixed in an internal mixer for 30 seconds, 20 parts by weight of butadiene rubber and 30 parts by weight of environmentally friendly aromatic oil were added in sequence and mixed for 300 seconds. At an initial temperature of 50°C, 5 parts by weight of tackifying resin, 10 parts by weight of white carbon black, 45 parts by weight of carbon black, 8 parts by weight of silane coupling agent, 3 parts by weight of zinc oxide, 5 parts by weight of antioxidant were added in sequence and mixed for 300 seconds. Then, 1.5 parts by weight of vulcanization accelerator, 10 parts by weight of sulfur were added in sequence and mixed for 300 seconds. The first-stage rubber mix is ​​refined on an open mixing mill, thinned 3 times, tapped 3 times, and packaged 5 times. The rubber mix is ​​then sheeted and allowed to stand for 24 hours to obtain a second-stage rubber mix. The second-stage rubber mix that has been allowed to stand is vulcanized on a flat vulcanizer at a temperature of 145°C ± 0.5°C and a pressure of 15 MPa to obtain a tread rubber composite material that is anti-skid, wear-resistant, and resistant to low temperatures.

[0022] Example 2: Application of vinyl cage silsesquioxane modified styrene-butadiene rubber. Based on Example 1, carbon black was changed to 40 parts by weight, white carbon black was changed to 15 parts by weight, and stearic acid was increased to 1 part by weight. Other formulas and processing conditions remained unchanged.

[0023] Example 3: Application of vinyl cage silsesquioxane modified styrene butadiene rubber. Based on Example 2, the modified styrene butadiene rubber is changed to 85 parts by weight, zinc oxide is changed to 3.1 parts by weight, the vulcanizing agent is changed to 2.3 parts by weight, and the vulcanization accelerator is changed to 1.6 parts by weight. Other formulas and processing conditions remain unchanged.

[0024] Comparative Example 1: 110 parts by weight of styrene-butadiene rubber (SBR1739), with a styrene binding degree of 40%, 20 parts by weight of butadiene rubber, 10 parts by weight of environmentally friendly aromatic oil, 5 parts by weight of adhesive resin, 45 parts by weight of carbon black, 10 parts by weight of white carbon black, 8 parts by weight of silane coupling agent, 3 parts by weight of zinc oxide, 5 parts by weight of antioxidant, 1.5 parts by weight of vulcanizing agent, and 2 parts by weight of vulcanizing agent. The mixing and processing conditions are the same as those in the embodiment.

[0025] Comparative Example 2: Based on Comparative Example 1, the amount of white carbon black was changed to 15 parts by weight, and stearic acid was added to 1 part by weight, while other formula designs and processing conditions remained unchanged.

[0026] The specific formulations of Examples 1-3 and Comparative Examples 1-2 are shown in Table 1.

[0027]

[0028] According to the above formula design and processing conditions, and in accordance with normal testing conditions, the results are shown in Table 2.

[0029]

[0030] Note: tanδ represents the loss factor. Usually, the tanδ value at 0℃ represents the wet grip of the rubber compound. The larger the value, the better the wet grip. The tanδ value at 60℃ represents the rolling resistance of the rubber compound. The smaller the value, the better and the lower the rolling resistance.

[0031] Based on the above results, it can be seen that the application of vinyl cage silsesquioxane modified styrene butadiene rubber in tire tread rubber can effectively improve the anti-skid performance and low-temperature resistance of the tire tread rubber, enhance the addition of wear-resistant agents, reduce the rolling resistance of the tread rubber, and significantly reduce wear. Example 2 is the best design application scheme, and the vehicle operation can maintain good safety performance in rainy and cold weather.

Claims

1. A method for preparing vinyl cage silsesquioxane modified styrene-butadiene rubber, characterized in that: Vinyl cage silsesquioxane is first subjected to a halogen addition reaction with hydrogen halide, and then grafted with styrene butadiene rubber through a Friedel-Crafts reaction. The specific steps are as follows: 1) a certain proportion of solvent and styrene butadiene rubber are added to a prefabricated mixing tank, and the mixture is fully stirred to prepare a styrene butadiene rubber prefabricated liquid for use; 2) nitrogen is introduced into a reactor to replace the air until the oxygen content is below 0.002%, and a solvent, a catalyst, and vinyl cage silsesquioxane are added in sequence. After thorough mixing, hydrogen halide gas is introduced into the reactor, and the reactor temperature and the ratio of the reactants are controlled at 20°C to 30°C. After the hydrogen halide gas is introduced, the reaction is continued for half an hour; 3) the reactor temperature is increased and controlled at 40°C to 63°C, the styrene butadiene rubber prefabricated liquid and 1 / 2 part by mass of the catalyst are added to the reactor, and the reaction is continued for 1 hour. The remaining catalyst is added to the reactor and the reaction is continued for 3 hours. After the reaction is completed, a certain amount of water is added, and the modified styrene butadiene rubber is obtained by washing, standing for separation, removing the solvent, and drying.

2. The method for preparing vinyl cage silsesquioxane modified styrene-butadiene rubber according to claim 1, wherein: The vinyl cage silsesquioxane is one or more of tetravinyl cage silsesquioxane, hexavinyl cage silsesquioxane, octavinyl cage silsesquioxane and decamethylene cage silsesquioxane.

3. The method for preparing vinyl cage silsesquioxane modified styrene-butadiene rubber according to claim 1, wherein: The solvent is one or more of toluene, xylene, tetrahydrofuran, and cyclohexane, wherein: in step 1), the solvent is mixed with styrene-butadiene rubber in a mass ratio of 5:1; and in step 2), the mass ratio of the solvent added to the reactor to the vinyl silsesquioxane is 5:

1.

4. The method for preparing vinyl cage silsesquioxane modified styrene-butadiene rubber according to claim 1, wherein: The hydrogen halide gas is one of HBr and HCl gases; the molar ratio of the hydrogen halide gas to the vinyl cage silsesquioxane is 1.01:

1.

5. The method for preparing vinyl cage silsesquioxane modified styrene-butadiene rubber according to claim 1, wherein: The catalyst is one or more of AlCl3, FeCl3, SnCl4, and ZnCl2; the amount of the catalyst added is 0.01-0.2% of the mass of the reactants.

6. The method for preparing vinyl cage silsesquioxane modified styrene-butadiene rubber according to claim 1, wherein: The modified styrene-butadiene rubber is a copolymer of styrene, butadiene and vinyl cage silsesquioxane; the bonding degree of styrene in the styrene-butadiene rubber is 40%, and the bonding degree of vinyl cage silsesquioxane and styrene is 8-10%.

Images