Rubber composition and application thereof, vulcanized rubber and preparation method and application thereof

Abstract

The invention relates to the field of material and rubber processing application, and discloses a rubber composition and application thereof, vulcanized rubber and a preparation method and application thereof. The rubber composition comprises 60-100 parts by mass of butadiene styrene rubber, 0-40 parts by mass of butadiene rubber, and relative to 100 parts by mass of rubber, 5-35 parts by mass of a plasticizer, 50-100 parts by mass of white carbon black, 4-10 parts by mass of a coupling agent, 2-8 parts by mass of a white carbon black dispersing agent, 0-30 parts by mass of carbon black, 2-5 parts by mass of an anti-aging agent, 3-5 parts by mass of a vulcanizing aid and 3-5 parts by mass of an activating agent. Wherein the styrene butadiene rubber is polar group modified styrene butadiene rubber, and the average number of polar groups contained in each molecular chain is not less than 3. When the vulcanized rubber prepared from the rubber composition is used in tires, the vulcanized rubber has good mechanical strength, low rolling resistance, high wet skid resistance and wear resistance.

Description

Technical Field

[0001] This invention relates to the fields of rubber materials and rubber processing applications, specifically to a rubber composition, a method for preparing vulcanized rubber, and the application of the vulcanized rubber, vulcanized rubber, or rubber composition prepared by the method in the manufacture of tires. Background Technology

[0002] With the worsening global energy crisis and environmental pollution, countries are paying increasing attention to energy conservation and environmental protection. To reduce fuel consumption and greenhouse gas emissions, the automotive industry is also moving towards energy conservation and environmental protection.

[0003] As a crucial safety component for vehicles, car tires are required to maintain good grip on the road surface while ensuring high mileage (tread wear resistance), especially good anti-skid performance on wet and icy roads. High-performance green tires, on the other hand, require low rolling resistance, good anti-skid performance, and excellent wear resistance.

[0004] Furthermore, due to the increasing severity of environmental problems and the depletion of petrochemical resources, bio-based oils have attracted attention as a substitute for petroleum-based processing oils in rubber composites. Aromatic oils, the most commonly used petroleum-based plasticizers in rubber, contain polycyclic aromatic hydrocarbons (PAHs) which have potential carcinogenicity. Additionally, to produce high-performance green tires, precipitated silica is already widely used in tire treads. When bio-based oils are added to tire treads as plasticizers, their polar groups can interact with the silane and silanol groups on the surface of precipitated silica, promoting the dispersion of precipitated silica in the rubber. Therefore, replacing petroleum mineral oils as plasticizers in rubber materials has become a future development trend. However, because bio-based oils have a certain degree of polarity, they have poor compatibility with non-polar rubbers such as natural rubber (NR) and styrene-butadiene rubber (SBR). Direct addition can lead to a significant decrease in the performance of vulcanized rubber, thus preventing their large-scale application in the rubber industry.

[0005] The paper "Rubber Industry" (2017, 64(12):729-73) investigated the effects of epoxidized soybean oil on the properties of silica-reinforced natural rubber composites. It found that when epoxidized soybean oil was added to the composite system via direct blending, the compatibility between the epoxidized soybean oil and the rubber matrix was poor, resulting in oil seepage. The tensile strength, heat generation properties, and rolling resistance of the vulcanized rubber were all significantly reduced. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned defects of the prior art and provide a rubber composition and its application with excellent mechanical properties, low heat generation, low rolling resistance, good anti-slip properties and wear resistance, as well as vulcanized rubber and its preparation method and application.

[0007] To achieve the above objectives, the first aspect of the present invention provides a rubber composition, wherein the rubber composition comprises 60-100 parts by weight of styrene-butadiene rubber, 0-40 parts by weight of butadiene rubber, and relative to 100 parts by weight of rubber, 5-35 parts by weight of plasticizer, 50-100 parts by weight of silica, 4-10 parts by weight of coupling agent, 2-8 parts by weight of silica dispersant, 0-30 parts by weight of carbon black, 2-5 parts by weight of antioxidant, 3-5 parts by weight of vulcanization aid, and 3-5 parts by weight of activator;

[0008] The styrene-butadiene rubber is a polar group modified styrene-butadiene rubber, and the average number of polar groups contained in each molecular chain is not less than 3.

[0009] A second aspect of the present invention provides a method for preparing vulcanized rubber from the above-described rubber composition, wherein the preparation method comprises the following steps:

[0010] (1) Plasticize styrene-butadiene rubber and optional butadiene rubber to obtain plasticized rubber, and then mix the plasticized rubber, silica, coupling agent, silica dispersant, carbon black, antioxidant and activator to obtain a first stage of masterbatch.

[0011] (2) The vulcanizing aid is mixed with the first stage masterbatch for a second time to obtain the final compound;

[0012] (3) The final rubber compound is vulcanized to obtain vulcanized rubber.

[0013] A third aspect of the present invention provides a vulcanized rubber prepared by the above method.

[0014] A fourth aspect of the present invention provides the use of the above-described rubber composition or vulcanized rubber in tires.

[0015] Through the above technical solutions, the rubber composition and its application, vulcanized rubber and its preparation method and application provided by the present invention achieve the following beneficial effects:

[0016] The rubber composition provided by this invention includes styrene-butadiene rubber modified with polar groups. When each molecular chain of the styrene-butadiene rubber contains a specific number of polar groups, it can effectively improve the compatibility of the styrene-butadiene rubber with plasticizers and other additives, especially with bio-based oils. This allows the vulcanized rubber prepared from the composition to have excellent mechanical strength. At the same time, the polar group-modified styrene-butadiene rubber has good affinity with silica. Preferably, a bio-based plasticizer is used as the plasticizer. The bio-based plasticizer can further modify the surface of silica, helping the silica to disperse well. As a result, the vulcanized rubber prepared from the composition can have excellent wear resistance, wet skid resistance, and low rolling resistance. Detailed Implementation

[0017] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0018] The first aspect of the present invention provides a rubber composition, wherein the rubber composition comprises: 60-100 parts by weight of styrene-butadiene rubber, 0-40 parts by weight of butadiene rubber, and relative to 100 parts by weight of rubber, 5-35 parts by weight of plasticizer, 50-100 parts by weight of silica, 4-10 parts by weight of coupling agent, 2-8 parts by weight of silica dispersant, 0-20 parts by weight of carbon black, 2-5 parts by weight of antioxidant, 3-6 parts by weight of vulcanization aid, and 3-5 parts by weight of activator;

[0019] The styrene-butadiene rubber is a polar group modified styrene-butadiene rubber, and the average number of polar groups contained in each molecular chain is not less than 3.

[0020] In this invention, the inventors discovered that when the molecular chain of styrene-butadiene rubber is modified by a certain number of polar groups, the compatibility of styrene-butadiene rubber with plasticizers and other additives, especially bio-based oils, can be effectively improved. This allows the plasticizer in the composition to modify the surface of silica without reducing the mechanical strength of the vulcanized rubber obtained therefrom. As a result, the vulcanized rubber obtained from this composition can have excellent mechanical strength, excellent wet skid resistance, low rolling resistance, and wear resistance.

[0021] In this invention, the average number of polar groups per molecular chain in the polar group-modified styrene-butadiene rubber is determined by the following method.

[0022] (1) The conversion rate of the polar modifier was determined using an Agilent 7890A gas chromatograph. The test conditions included: SPB-560m×0.32mm×1μm capillary column, column flow rate of 2mL / min, column temperature of 220℃, vaporization chamber temperature of 220℃, detection chamber temperature of 250℃, split ratio of 50:1, and injection volume of 0.3μL. The number-average molecular weight and molecular weight distribution were determined using a Waters Allion 2690 gel permeation chromatograph (GPC) with THF as the mobile phase, narrow-distribution polystyrene as the standard, and a temperature of 25℃.

[0023] (2) The average number of polar groups per molecular chain = amount of polar modifier × conversion rate of polar modifier ÷ relative molecular mass of polar modifier ÷ (amount of styrene + amount of butadiene) × number average molecular weight of rubber molecules.

[0024] In this invention, the content of vinyl groups in the polar group-modified styrene-butadiene rubber is 46-48 wt%, and the content of styrene is 20-21 wt%.

[0025] In this invention, the vinyl content and styrene content of the modified styrene-butadiene rubber were determined using an AVANCE DRX400MHz nuclear magnetic resonance spectrometer from Bruker GmbH, Switzerland, and the solvent was deuterated chloroform.

[0026] In this invention, the number-average molecular weight of the polar group-modified styrene-butadiene rubber is 180,000-200,000 g / mol.

[0027] Further, the rubber composition comprises 70-85 parts by weight of styrene-butadiene rubber, 15-30 parts by weight of butadiene rubber, and relative to 100 parts by weight of rubber, 15-25 parts by weight of plasticizer, 60-80 parts by weight of silica, 5-8 parts by weight of coupling agent, 3-6 parts by weight of silica dispersant, 5-20 parts by weight of carbon black, 2-5 parts by weight of antioxidant, 3-5 parts by weight of vulcanization aid, and 3-5 parts by weight of activator;

[0028] And / or, the styrene-butadiene rubber is a polar group modified styrene-butadiene rubber and the average number of functional groups per molecular chain is 5-15.

[0029] According to the present invention, the polar group is selected from at least one of carboxyl, amino, hydroxyl and siloxane groups.

[0030] In this invention, when styrene-butadiene rubber is modified with the aforementioned specific types of polar groups, its compatibility with bio-based oils and silica is significantly enhanced, allowing the bio-based oils and silica to be uniformly dispersed in the rubber matrix. The resulting vulcanizate exhibits excellent mechanical properties, low rolling resistance, and high anti-slip properties. Preferably, the polar groups are selected from at least one of carboxyl, amino, and hydroxyl groups.

[0031] In this invention, there is no particular limitation on the source of the polar group modified styrene-butadiene rubber; it can be commercially available or made in-house.

[0032] In one specific embodiment of the present invention, the polar group-modified styrene-butadiene rubber is prepared according to the following steps:

[0033] A polar modifier that provides polar groups is added to SSBR adhesive, and an initiator is added under heating conditions to carry out a polar modification reaction, thereby obtaining the polar group-modified styrene-butadiene rubber.

[0034] In this invention, the SSBR adhesive is derived from the process of synthesizing SSBR, or the SSBR adhesive is obtained by mixing SSBR with an organic solvent.

[0035] In this invention, there is no particular limitation on the type of organic solvent, which can be a conventional organic solvent in the art, such as cyclohexane and / or n-hexane.

[0036] In this invention, there is no particular limitation on the type of polar modifier that provides polar groups, as long as it can provide polar groups, such as at least one polar group selected from carboxyl, amino, hydroxyl and siloxane, such as at least one selected from 3-mercapto-1-propionic acid, 3-mercapto-1-propane and 3-mercapto-1-propanol.

[0037] In this invention, there is no particular limitation on the type of polar modifier, as long as the amount of polar modifier is sufficient to ensure that the average number of functional groups per molecular chain in the obtained polar group modified SSBR meets the range defined by this invention.

[0038] In this invention, there is no particular limitation on the type of initiator, which can be a conventional initiator in the art, such as azobisisobutyronitrile. There is also no particular limitation on the amount of initiator used, as long as it ensures sufficient reaction between the SSBR and the polar modifier, and that the average number of functional groups per molecular chain in the obtained polar group-modified SSBR meets the range defined in this invention.

[0039] In this invention, the heating conditions are not particularly limited, for example, they can be 60-85°C.

[0040] In this invention, there are no particular limitations on the conditions for polar modification, as long as the polar modifier can react with SSBR. For example, the pressure is 0.1-0.5 MPa and the time is 1-5 h.

[0041] According to the present invention, the content of the cis-1,4 structure in the cis-butadiene rubber is 90-99 wt%.

[0042] In a preferred embodiment of the present invention, the butadiene rubber is neodymium-based rare earth butadiene rubber, wherein the content of cis-1,4 structure is 98-99 wt%.

[0043] According to the present invention, the styrene-butadiene rubber is solution-polymerized styrene-butadiene rubber.

[0044] According to the present invention, the plasticizer is a bio-based plasticizer.

[0045] In this invention, to further enhance the compatibility between the plasticizer and the rubber matrix, and to promote the uniform dispersion of silica, a substance containing active groups that react with the polar groups modified styrene-butadiene rubber and silica is used as the plasticizer. Preferably, the plasticizer is selected from at least one of epoxidized soybean oil, epoxidized palm oil, epoxidized castor oil, epoxidized rapeseed oil, and epoxidized sunflower oil.

[0046] According to the present invention, the nitrogen adsorption specific surface area of ​​the silica is 100-220 m². 2 / g, preferably 140-180m 2 / g.

[0047] According to the present invention, the carbon black has an iodine absorption value of 70-150 g / kg and a DBP absorption value of 90 × 10⁻⁶ g / kg. -5 m 3 / kg-140×10 -5 m 3 / kg.

[0048] Furthermore, the carbon black has an iodine absorption value of 80-140 g / kg and a DBP absorption value of 100 × 10⁻⁶ g / kg. -5 m 3 / kg-130×10 -5 m 3 / kg.

[0049] According to the present invention, the coupling agent is a silane coupling agent, such as at least one selected from bis-[γ-(triethoxysilyl)propyl]tetrasulfide, bis-[triethoxysilyl)propyl]disulfide, dodecyltriethoxysilane, hexadecyltriethoxysilane, γ-thiomercaptopropyltrimethoxysilane, γ-ylmercaptopropyltriethoxysilane, silane coupling agent Si747, and silane coupling agent NXT.

[0050] According to the present invention, the silica dispersant is selected from polyethylene glycol and / or zinc soap salts.

[0051] According to the present invention, the antioxidant is selected from at least one of physical antioxidants, amine antioxidants, phenolic antioxidants, quinoline antioxidants and benzimidazole antioxidants.

[0052] According to the present invention, the activator is selected from a combination of metal oxides and fatty acids; preferably, the metal oxide is selected from zinc oxide and / or magnesium oxide; preferably, the fatty acid is selected from stearic acid.

[0053] In this invention, there is no particular limitation on the amount of metal oxide and fatty acid in the activator. For example, the amount of metal oxide is 2-3 parts by mass and the amount of fatty acid is 1-2 parts by mass.

[0054] According to the present invention, the vulcanization aid includes a vulcanizing agent and an accelerator.

[0055] In this invention, there is no particular limitation on the amount of vulcanizing agent and accelerator in the vulcanization aid. The amounts can be in accordance with conventional amounts in the art, for example, the amount of vulcanizing agent is 0.8-1.5 parts by weight and the amount of accelerator is 2.2-4.2 parts by weight.

[0056] According to the present invention, the vulcanizing agent is sulfur.

[0057] According to the present invention, the accelerator is at least one selected from sulfenamide accelerators, guanidine accelerators, and dithiocarbamate accelerators. In the present invention, when the accelerator is a combination of sulfenamide accelerators, guanidine accelerators, and dithiocarbamate accelerators, there is no particular limitation on the amount of each sulfenamide accelerator, guanidine accelerator, and dithiocarbamate accelerator; they can be used according to conventional amounts in the art. For example, the amount of sulfenamide accelerator is 1.7-2 parts by weight, the amount of guanidine accelerator is 0-2 parts by weight, and the amount of dithiocarbamate accelerator is 0-0.2 parts by weight.

[0058] In this invention, there is no particular limitation on the type of sulfenamide accelerator; conventional sulfenamide accelerators in the art, such as N-tert-butyl-2-benzothiazole sulfenamide, can be used. Similarly, there is no particular limitation on the specific type of guanidine accelerator; conventional guanidine accelerators in the art, such as diphenylguanidine, can be used. Furthermore, there is no particular limitation on the specific type of dithiocarbamate accelerator; conventional dithiocarbamate accelerators in the art, such as zinc dibenzyl dithiocarbamate, can be used.

[0059] A second aspect of the present invention provides a method for preparing vulcanized rubber from the above-described rubber composition, wherein the method comprises the following steps:

[0060] (1) Plasticize styrene-butadiene rubber and optional butadiene rubber to obtain plasticized rubber, and then mix the plasticized rubber, silica, coupling agent, silica dispersant, carbon black, antioxidant and activator to obtain a first stage of masterbatch.

[0061] (2) The vulcanizing aid is mixed with the first stage masterbatch for a second time to obtain the final compound;

[0062] (3) The final rubber compound is vulcanized to obtain vulcanized rubber.

[0063] In this invention, all substances involved in the second aspect have the same properties as the same substances in the first aspect of this invention. In order to avoid repetition, certain characteristics of substances (such as the optional types of substances) are not repeated in the second aspect of this invention. Those skilled in the art should not understand this as a limitation on the second aspect of this invention.

[0064] In this invention, there are no special requirements for the equipment used for plasticizing or mixing; conventional equipment in the field, such as an internal mixer, can be used.

[0065] According to the present invention, the plasticizing conditions include: plasticizing time of 0.5-2 min and plasticizing temperature of 60-100℃.

[0066] According to the present invention, the conditions for the first mixing include: a mixing time of 2-8 min, preferably 4-7 min; and a mixing temperature of 120-160°C, preferably 145-155°C.

[0067] According to the present invention, the conditions for the second mixing include: a mixing time of 4-7 min, preferably 4-5 min; and a mixing temperature not exceeding 120°C, preferably 90-110°C.

[0068] According to the present invention, the vulcanization conditions include: a vulcanization temperature of 150-170°C, a vulcanization pressure of 10-20 MPa, and a vulcanization time of 10-40 min.

[0069] In one specific embodiment of the present invention, the first mixing includes the following steps:

[0070] After the plasticized rubber, 50-80 wt% silica, and coupling agent are mixed in the first compounding I, the remaining silica, carbon black, plasticizer, silica dispersant, activator, and antioxidant are added and mixed in the first compounding II to obtain a masterbatch.

[0071] In this invention, the time for the first mixing I is 1-3 minutes, and the time for the first mixing II is 1-5 minutes.

[0072] In this invention, unless otherwise specified, all pressures used are gauge pressures.

[0073] A third aspect of the present invention provides a vulcanized rubber prepared by the above method.

[0074] A fourth aspect of the present invention provides the use of the above-described rubber composition or vulcanized rubber in tires.

[0075] The present invention will be described in detail below through examples. Unless otherwise specified, all raw materials used in the following examples are commercially available.

[0076] The equipment used for preparing vulcanized rubber in the following examples and comparative examples is shown in Table 1.

[0077] The testing instruments for the vulcanized rubbers prepared in the examples and comparative examples are shown in Table 2, and the testing conditions are shown in Table 3.

[0078] The raw materials used in the examples and comparative examples are as follows:

[0079] Rare earth butadiene rubber Nd40: The content of cis-1,4 structure accounts for 98.4 wt% of the total polymer weight, produced by Yanshan Petrochemical;

[0080] Silica: Nitrogen adsorption specific surface area is 170m² 2 / g of highly dispersible silica, commercially available;

[0081] Carbon black N134: Iodine absorption value 142 g / kg, DBP absorption value 127 × 10⁻⁶ g / kg -5 m 3 / kg, purchased commercially.

[0082] Table 1

[0083] Serial Number Equipment Name model Manufacturer 1 Internal mixer BR1600 British Farrell Company 2 open mill XK-160 Qingdao Xincheng Yiming Machinery Co., Ltd. 3 Flat vulcanizing machine XLB-D400*400*2 Shanghai No.1 Rubber Machinery Factory

[0084] Table 2

[0085] Serial Number Test Project Test instrument model Manufacturer 1 Tensile strength SHIMADZU AG-20KNG Multi-purpose tensile testing machine Shimadzu Corporation of Japan 2 Tear strength SHIMADZU AG-20KNG Multi-purpose tensile testing machine Shimadzu Corporation of Japan 3 DIN wear DIN Abrasion Testing Machine, GT-7021 High-speed rail instrument company 4 Dynamic mechanical properties Dynamic thermomechanical analyzer, EPLEXOR 500N GABO, Germany

[0086] Table 3

[0087]

[0088]

[0089] Preparation Example 1 – Polar Group Modified Styrene-Butadiene Rubber SSBR-1

[0090] (1) Under the protection of high-purity nitrogen, 2450g of mixed solvent (cyclohexane to n-hexane mass ratio of 82:18), 62.7g of styrene and 246.8g of butadiene were mixed, and then 2,2-bis(2-tetrahydrofuranyl)propane (the amount of 2,2-bis(2-tetrahydrofuranyl)propane was added (relative to the total weight of 1000g of mixed solvent, styrene and butadiene, the amount of 2,2-bis(2-tetrahydrofuranyl)propane was 300mg). 2mmol of n-butyllithium was added at 50°C to initiate the anionic polymerization reaction, and the reaction was carried out at 50°C for 60 minutes to obtain a glue containing olefin polymer.

[0091] (2) Add 0.9285g of 3-mercapto-1-propionic acid to the adhesive solution and immediately take a sample for mercapto test; then heat to 75℃ and add 6.5mg of azobisisobutyronitrile, and control the pressure at 0.2MPa for 3 hours to obtain modified olefin polymer adhesive solution, and take a sample for mercapto test to calculate the conversion rate of polar modifier. After the adhesive solution is condensed by water vapor, polar group modified solution styrene-butadiene rubber SSBR-1 is obtained.

[0092] According to tests and calculations, the styrene content in the polar group modified solution-polymerized styrene-butadiene rubber SSBR-1 is 20.3 wt%, the vinyl content is 46.4 wt%, the number average molecular weight is 187,000 g / mol, and the average number of carboxyl groups per molecular chain is 5.1.

[0093] Preparation Example 2 – Polar Group Modified Styrene-Butadiene Rubber SSBR-2

[0094] (1) Same as step (1) of preparation example 1;

[0095] (2) Add 1.5475g of 3-mercapto-1-propionic acid to the adhesive solution and immediately take a sample for mercapto test. Then heat to 75℃ and add 6.5mg of azobisisobutyronitrile. After reacting for 3 hours under pressure of 0.2MPa, a modified olefin polymer adhesive solution is obtained. Take a sample for mercapto test to calculate the conversion rate of polar modifier. After the adhesive solution is condensed by water vapor, polar group modified solution styrene-butadiene rubber SSBR-2 is obtained.

[0096] According to tests and calculations, the styrene content in the polar group modified solution-polymerized styrene-butadiene rubber SSBR-2 is 20.7 wt%, the vinyl content is 46.1 wt%, the number average molecular weight is 193,000 g / mol, and the average number of carboxyl groups per molecular chain is 8.5.

[0097] Preparation Example 3 – Polar Group Modified Styrene-Butadiene Rubber SSBR-3

[0098] (1) Same as step (1) of preparation example 1;

[0099] (2) Add 3.0950g of 3-mercapto-1-propionic acid to the adhesive solution and immediately take a sample for mercapto test. Then heat to 75℃ and add 6.5mg of azobisisobutyronitrile. After reacting for 3 hours under pressure of 0.2MPa, a modified olefin polymer adhesive solution is obtained. Take a sample for mercapto test to calculate the conversion rate of polar modifier. After the adhesive solution is condensed by water vapor, polar group modified solution styrene-butadiene rubber SSBR-3 is obtained.

[0100] According to tests and calculations, the styrene content in the polar group modified solution-polymerized styrene-butadiene rubber SSBR-3 is 20.5 wt%, the vinyl content is 46.7 wt%, the number average molecular weight is 186,000 g / mol, and the average number of carboxyl groups per molecular chain is 14.9.

[0101] Preparation Example 4 – Polar Group Modified Styrene-Butadiene Rubber SSBR-4

[0102] (1) Same as step (1) of preparation example 1;

[0103] (2) Add 1.5475g of 3-mercapto-1-propane to the adhesive solution and immediately take a sample for mercapto testing. Then heat to 75℃ and add 6.5mg of azobisisobutyronitrile. After reacting for 3 hours under pressure of 0.2MPa, a modified olefin polymer adhesive solution is obtained. Take a sample for mercapto testing to calculate the conversion rate of the polar modifier. After the adhesive solution is condensed by water vapor, polar group modified solution-polymerized styrene-butadiene rubber SSBR-4 is obtained.

[0104] According to tests and calculations, the styrene content in the polar group modified solution-polymerized styrene-butadiene rubber SSBR-4 is 20.3 wt%, the vinyl content is 46.7 wt%, the number average molecular weight is 186,000 g / mol, and the average number of amino groups per molecular chain is 8.2.

[0105] Preparation Example 5 – Polar Group Modified Styrene-Butadiene Rubber SSBR-5

[0106] (1) Same as step (1) of preparation example 1;

[0107] (2) Add 1.5475g of 3-mercapto-1-propanol to the adhesive solution and immediately take a sample for mercapto test. Then heat to 75℃ and add 6.5mg of azobisisobutyronitrile. After reacting for 3 hours under pressure of 0.2MPa, a modified olefin polymer adhesive solution is obtained. Take a sample for mercapto test to calculate the conversion rate of polar modifier. After the adhesive solution is condensed by water vapor, polar group modified solution styrene-butadiene rubber SSBR-5 is obtained.

[0108] According to tests and calculations, the styrene content in the polar group modified solution-polymerized styrene-butadiene rubber SSBR-5 is 20.1 wt%, the vinyl content is 47.2 wt%, the number average molecular weight is 196,000 g / mol, and the average number of hydroxyl groups per molecular chain is 8.3.

[0109] Comparative preparation example—unmodified styrene-butadiene rubber (SSBR)

[0110] Under high-purity nitrogen protection, 2450g of mixed solvent (cyclohexane to n-hexane mass ratio of 82:18), 62.7g of styrene and 246.8g of butadiene were mixed, and then 2,2-bis(2-tetrahydrofuranyl)propane (the amount of 2,2-bis(2-tetrahydrofuranyl)propane was added (300mg relative to the total amount of 1000g of mixed solvent, styrene and butadiene). 2mmol of n-butyllithium was added at 50°C to initiate anionic polymerization, and the reaction was carried out at 50°C for 60 minutes. The reaction was then completed to obtain a solution containing olefin polymer. After the solution was condensed by water vapor, solution-polymerized styrene-butadiene rubber (SSBR) was obtained.

[0111] Tests showed that the styrene content in solution-polymerized styrene-butadiene rubber (SSBR) was 20.3 wt%, the vinyl content was 47.1 wt%, and the number average molecular weight was 194,000 g / mol.

[0112] Example 1

[0113] The formulations of each component in the rubber composition S1 of Example 1 are shown in Table 4 (where the values ​​are parts by weight relative to 100 parts by weight of the base rubber, the same below). The specific method for preparing the vulcanized rubber S1 of Example 1 is as follows:

[0114] The internal mixer is set to an initial speed of 100 rpm and an initial mixing temperature of 60℃. The raw rubber is plasticized for 0.5 min. The stopper is lifted, and 3 / 4 of the silica and silane coupling agent are added and mixed for 2 min. The stopper is lifted again, and 1 / 4 of the silica, carbon black, plasticizer, silica dispersant, activator, and antioxidant are added. After the temperature rises to 150℃, the speed is varied and the temperature is kept constant at 150℃ for 5 min. The mixture is then discharged and left to stand for 4 h. The internal mixer is set to an initial speed of 60 rpm and an initial mixing temperature of 40℃. The vulcanizing agent, accelerator, and first-stage masterbatch are mixed for 4 min. The maximum mixing temperature is 100-110℃. The mixture is then discharged.

[0115] Vulcanized rubber S1 is obtained.

[0116] Example 2

[0117] Example 2 uses the same method as Example 1 to prepare vulcanized rubber, except that:

[0118] The rubber composition formulation in Example 2 differs from that in Example 1. The formulations of each component in rubber composition S2 are shown in Table 4.

[0119] Vulcanized rubber S2 is obtained.

[0120] Example 3

[0121] Example 3 uses the same method as Example 1 to prepare vulcanized rubber, except that:

[0122] The rubber composition formulation in Example 3 differs from that in Example 1. The formulations of each component in rubber composition S3 are shown in Table 4.

[0123] Vulcanized rubber S3 is obtained.

[0124] Example 4

[0125] Example 4 uses the same method as Example 1 to prepare vulcanized rubber, except that:

[0126] The rubber composition formulation in Example 4 differs from that in Example 1. The formulations of each component in rubber composition S4 are shown in Table 4.

[0127] Vulcanized rubber S4 is obtained.

[0128] Example 5

[0129] Example 5 uses the same method as Example 1 to prepare vulcanized rubber, except that:

[0130] The rubber composition formulation in Example 5 differs from that in Example 1. The formulations of each component in rubber composition S5 are shown in Table 4.

[0131] Vulcanized rubber S5 is obtained.

[0132] Example 6

[0133] Example 6 uses the same method as Example 1 to prepare vulcanized rubber, except that:

[0134] The rubber composition formulation in Example 6 differs from that in Example 1. The formulations of each component in rubber composition S6 are shown in Table 4.

[0135] Vulcanized rubber S6 was obtained.

[0136] Comparative Example 1

[0137] Comparative Example 1 used the same method as Example 1 to prepare vulcanized rubber, except that:

[0138] The rubber composition formulation in Comparative Example 1 differs from that in Example 1. The formulations of each component in rubber composition D1 are shown in Table 4.

[0139] Vulcanized rubber D1 is obtained.

[0140] Comparative Example 2

[0141] Comparative Example 2 used the same method as Example 1 to prepare vulcanized rubber, except that:

[0142] The rubber composition formulation in Comparative Example 2 differs from that in Example 1. The formulations of each component in rubber composition D2 are shown in Table 4.

[0143] Vulcanized rubber D2 is obtained.

[0144] Table 4

[0145] S1 S2 S3 S4 S5 S6 D1 D2 SSBR / / / / / 70 70 SSBR-1 / / 85 / / / / / SSBR-2 70 / / / / 70 / / SSBR-3 / 80 / / / / / / SSBR-4 / / / 60 / / / / SSBR-5 / / / / 100 / / / butadiene rubber 30 20 15 40 / 30 30 30 precipitate 80 60 70 100 50 80 80 80 carbon black 5 20 10 / 30 5 5 5 Epoxidized soybean oil 15 / 20 5 35 / 15 / Epoxidized palm oil / 25 / / / / / / soybean oil / / / / / 15 / / Environmentally friendly aromatic oil / / / / / / / 15 PEG4000 6 3 4.5 8 2 6 6 6 Si69 8 5 6 10 4 8 8 8 Zinc oxide 2 3 2 2 3 2 2 2 stearic acid 1 2 2 1 2 1 1 1 Protective wax 2 / 2 2 2 2 2 2 Anti-aging agent 4020 2 2 2 2 2 2 2 2 Anti-aging agent RD 1 / / 1 1 1 1 1 sulfur 0.8 1.5 0.8 0.8 1.5 0.8 0.8 0.8 Accelerator TBBS 2 1.7 2 2 1.7 2 2 2 Accelerator ZBEC 0.2 / 0.2 0.2 / 0.2 0.2 0.2 Accelerator D 2 1.8 / 2 1.8 2 2 2

[0146] Table 5

[0147] S1 S2 S3 S4 S5 S6 D1 D2 100% Modulus / MPa 4.2 3.9 3.9 4.7 4.0 4.4 4.0 4.9 Tensile strength / MPa 18.7 19.2 17.9 17.1 20.1 16.9 12.1 16.7 Elongation at break / % 327 334 305 276 308 259 221 273 Tear strength / kN / m 34 36 34 32 34 32 29 31 Tanδ(0℃) 0.377 0.423 0.465 0.317 0.729 0.359 0.322 0.330 Tanδ (60℃) 0.109 0.116 0.111 0.127 0.120 0.122 0.137 0.129 <![CDATA[DIN wear amount / mm 3 > 86 95 97 91 110 114 120 106

[0148] The results above show that the vulcanized rubber made from the rubber composition of the present invention, using bio-based oil as a plasticizer, exhibits significantly higher tensile strength, tear strength, and abrasion resistance than the comparative example. (1230751)

[0149] I91429BHY

[0150] The dynamic drag performance and anti-slip performance are also significantly improved compared with the comparative example.

[0151] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A rubber composition, characterized in that, The rubber composition comprises: 60-100 parts by weight of styrene-butadiene rubber, 0-40 parts by weight of butadiene rubber, 5-35 parts by weight of plasticizer relative to 100 parts by weight of rubber, 50-100 parts by weight of silica, 4-10 parts by weight of coupling agent, 2-8 parts by weight of silica dispersant, 0-30 parts by weight of carbon black, 2-5 parts by weight of antioxidant, 3-5 parts by weight of vulcanization aid, and 3-5 parts by weight of activator; The styrene-butadiene rubber is a polar group modified styrene-butadiene rubber; and the average number of polar groups contained in each molecular chain is not less than 3.

2. The rubber composition according to claim 1, wherein, The rubber composition comprises: 70-85 parts by weight of styrene-butadiene rubber, 15-30 parts by weight of butadiene rubber, 15-25 parts by weight of plasticizer relative to 100 parts by weight of rubber, 60-80 parts by weight of silica, 5-8 parts by weight of coupling agent, 3-6 parts by weight of silica dispersant, 5-20 parts by weight of carbon black, 2-5 parts by weight of antioxidant, 3-5 parts by weight of vulcanization aid, and 3-5 parts by weight of activator; And / or, the styrene-butadiene rubber is a polar group modified styrene-butadiene rubber and the average number of polar groups contained in each molecular chain is 5-15.

3. The rubber composition according to claim 1 or 2, wherein, The polar modifying group is selected from at least one of carboxyl, amino, hydroxyl and siloxane, preferably at least one of carboxyl, amino and hydroxyl.

4. The rubber composition according to any one of claims 1-3, wherein, The content of the cis-1,4 structure in the cis-butadiene rubber is 90-99 wt%. Preferably, the styrene-butadiene rubber is solution-polymerized styrene-butadiene rubber.

5. The rubber composition according to any one of claims 1-4, wherein, The plasticizer is a bio-based plasticizer, preferably selected from at least one of soybean oil, palm oil, castor oil, rapeseed oil, and sunflower seed oil; more preferably selected from at least one of epoxidized soybean oil, epoxidized palm oil, epoxidized castor oil, epoxidized rapeseed oil, and epoxidized sunflower seed oil.

6. The rubber composition according to any one of claims 1-5, wherein, The adsorption specific surface area of ​​nitrogen in the precipitated silica is 100-220 m². 2 / g.

7. The rubber composition according to any one of claims 1-6, wherein, The carbon black has an iodine absorption value of 70-150 g / kg and a DBP absorption value of 90 × 10⁻⁶ g / kg. -5 m 3 / kg-140×10 -5 m 3 / kg; Preferably, the coupling agent is a silane coupling agent; Preferably, the silica dispersant is selected from polyethylene glycol and / or zinc soap salts; Preferably, the antioxidant is selected from at least one of physical antioxidants, amine antioxidants, phenolic antioxidants, quinoline antioxidants, and benzimidazole antioxidants; Preferably, the activator is selected from a combination of metal oxides and fatty acids; Preferably, the metal oxide is selected from zinc oxide and / or magnesium oxide; Preferably, the fatty acid is selected from stearic acid; Preferably, the vulcanization aid includes a vulcanizing agent and an accelerator; Preferably, the vulcanizing agent is sulfur; Preferably, the accelerator is selected from at least one of sulfenamide accelerators, guanidine accelerators, and dithiocarbamate accelerators.

8. A method for preparing vulcanized rubber from the rubber composition according to any one of claims 1-7, characterized in that, The method includes the following steps: (1) Plasticize styrene-butadiene rubber and optional butadiene rubber to obtain plasticized rubber, and then mix the plasticized rubber, silica, coupling agent, silica dispersant, carbon black, antioxidant and activator to obtain a first stage of masterbatch. (2) The vulcanizing aid is mixed with the first stage masterbatch for a second time to obtain the final compound; (3) The final rubber compound is vulcanized to obtain vulcanized rubber.

9. The preparation method according to claim 8, wherein, The plasticizing conditions include: plasticizing time of 0.5-2 min and plasticizing temperature of 60-100℃; Preferably, the conditions for the first mixing include: a mixing time of 2-8 minutes and a mixing temperature of 120-160°C, preferably 145-155°C; Preferably, the conditions for the second mixing include: a mixing time of 4-7 min, more preferably 4-5 min; and a mixing temperature not exceeding 120°C, more preferably 90-110°C. Preferably, the vulcanization conditions include: a vulcanization temperature of 150-170℃, a vulcanization pressure of 10-20MPa, and a vulcanization time of 10-40min.

10. The preparation method according to claim 8 or 9, wherein, The first mixing includes the following steps: After the plasticized rubber, 50-80 wt% silica, and coupling agent are mixed in the first compounding I, the remaining silica, carbon black, plasticizer, silica dispersant, activator, and antioxidant are added and mixed in the first compounding II to obtain a masterbatch.

11. A vulcanized rubber prepared by any one of claims 8-10.

12. The use of the rubber composition according to any one of claims 1-7 or the vulcanized rubber according to claim 11 in a tire, preferably in the tire tread.

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