Rubber composition for tire sidewall, rubber compound for tire sidewall and preparation method of rubber compound

Abstract

The invention provides a rubber composition for a tire sidewall, a rubber compound for the tire sidewall and a preparation method of the rubber compound. The rubber composition comprises the following components in parts by weight: 100 parts of rubber, 30-70 parts of carbon black, 2-20 parts of an anti-aging agent, 1-15 parts of an active agent, 0.5-4 parts of a vulcanizing agent, 0.5-6 parts of an accelerant and 1-10 parts of an auxiliary agent, the anti-aging agent comprises a p-phenylenediamine anti-aging agent, the p-phenylenediamine anti-aging agent is an anti-aging agent A with a structure as shown in a formula I and / or an anti-aging agent B with a structure as shown in a formula II, and a rubber compound prepared from the rubber composition with the number being # imgabs0 # or above has excellent physical performance and anti-aging performance and is more suitable for tire sidewall production. Besides, toxicity detection is carried out on rubber residues, and high-toxicity quinonized products are not detected after detection, so that the rubber composition for the tire sidewall is environment-friendly and non-toxic, and has good environmental protection performance.

Description

Technical Field

[0001] The present invention relates to the field of rubber technology, and in particular to a rubber composition for tire sidewalls, a rubber compound for tire sidewalls and a preparation method thereof. Background Art

[0002] The sidewall of a tire is an important part of its structure and mechanical properties. It mainly bears the lateral force and impact force generated during the driving of the vehicle. Therefore, the sidewall needs to have good wear resistance, heat resistance, fatigue resistance, etc. The performance of the rubber composition used for the sidewall directly determines the performance of the tire.

[0003] Rubber aging is mainly caused by environmental factors such as oxygen, ozone, humidity, ultraviolet rays, heat, mechanical stress, etc., which lead to changes in rubber structure and degradation of physical properties, ultimately affecting the function and life of rubber products. The addition of antioxidants is an effective strategy to prevent rubber aging and extend its service life. They improve the fatigue resistance and aging resistance of rubber by inhibiting or slowing down the chemical changes of rubber under environmental and mechanical stress, such as oxidation and ozonation reactions.

[0004] Paraphenylenediamine antioxidants are widely used in tire manufacturing due to their excellent protective effect, especially in the sidewalls of giant engineering machinery tires, which are the parts of tires that are most susceptible to environmental factors and mechanical stress. However, during use, these antioxidants may interact with fillers such as carbon black, thereby affecting the dispersion of carbon black in the rubber matrix and reducing the processing performance of the rubber compound. Uniform dispersion of carbon black is essential to ensure the mechanical strength and wear resistance of the rubber composition, while uneven dispersion will lead to a decrease in mechanical properties and increase the failure rate and maintenance cost of the tire during use.

[0005] However, the most widely used antioxidant is p-phenylenediamine antioxidant, such as rubber antioxidant 4020, whose chemical name is N-(1,3-dimethylbutyl)-N'-phenyl p-phenylenediamine. It belongs to the same p-phenylenediamine antioxidant as antioxidants 4010NA and 4010, and is a highly effective rubber antioxidant. This type of p-phenylenediamine antioxidant may be converted into highly toxic quinone products during ozone aging in the natural environment. After the tire's life cycle ends, the antioxidant conversion products in the tire fragments have potential hazards to the aquatic environment and ecosystem, and may even affect human health.

[0006] Therefore, there is an urgent need to develop an environmentally friendly giant engineering machinery tire sidewall rubber composition. Summary of the invention

[0007] The main purpose of the present invention is to provide a rubber composition for tire sidewalls, a rubber compound for tire sidewalls and a preparation method thereof, so as to solve the problem that the p-phenylenediamine antioxidant in the rubber composition in the prior art undergoes ozone aging to generate highly toxic quinone products.

[0008] In order to achieve the above object, according to one aspect of the present invention, a rubber composition for tire sidewall is provided, which comprises, by weight: 100 parts of rubber, 30 to 70 parts of carbon black, 2 to 20 parts of antioxidant, 1 to 15 parts of activator, 0.5 to 4 parts of vulcanizer, 0.5 to 6 parts of accelerator and 1 to 10 parts of auxiliary agent; the antioxidant comprises a p-phenylenediamine antioxidant, the p-phenylenediamine antioxidant is an antioxidant A having a structure shown in formula I and / or an antioxidant B having a structure shown in formula II,

[0009] Furthermore, the rubber composition comprises, by weight: 100 parts of rubber, 35 to 60 parts of carbon black, 3 to 15 parts of antioxidant, 2 to 8 parts of activator, 1 to 3 parts of vulcanizing agent, 1 to 2.5 parts of accelerator and 3 to 8 parts of auxiliary agent; and / or the specific surface area of ​​carbon black is 20 to 400 m 2 / g, preferably 20 to 200 m 2 / g, more preferably 50 to 150 m 2 / g.

[0010] Furthermore, when the p-phenylenediamine antioxidant is a combination of antioxidant A and antioxidant B, the mass ratio of antioxidant A to antioxidant B is 1 to 5:1; and / or the antioxidant further includes protective wax and / or antioxidant RD.

[0011] Furthermore, the rubber is selected from any one or more of natural rubber, polyisoprene rubber and polybutadiene rubber; preferably, the rubber is a combination of natural rubber and polyisoprene rubber; preferably, the rubber is a combination of natural rubber and polybutadiene rubber; and / or, the molecular weight of the rubber is 1000 to 400 million, preferably 5000 to 300 million, and more preferably 10000 to 8 million.

[0012] Further, the auxiliary agent is a coupling agent and / or a softener; wherein the coupling agent is selected from any one or more of bis(triethoxypropylsilane)tetrasulfide, bis(triethoxypropylsilane)disulfide, 3-thiocyanatopropyl-triethoxysilane, γ-mercaptopropyl-trimethoxysilane, zirconate coupling agent, phthalate coupling agent and nitro coupling agent; and / or, based on 100 parts by weight of rubber, the amount of the coupling agent is 0 to 8 parts by weight, preferably 0 to 4 parts by weight; and / or, the softener is oil and / or resin; the oil is aromatic oil, the resin is a tackifying resin and / or a tear-resistant resin, preferably the tackifying resin is selected from any one or more of tert-butylphenolic resin, C5 petroleum resin and C9 petroleum resin, preferably the tear-resistant resin is rosin and / or C9 mixed resin and / or, based on 100 parts by weight of rubber, the amount of the softener is 0 to 20 parts by weight, preferably 0 to 10 parts by weight; and / or, the activator is zinc oxide and / or stearic acid; and / or, the vulcanizing agent is selected from any one or more of sulfur, a sulfur donor and a peroxide; and / or, the accelerator is selected from any one or more of a thiazole accelerator, a sulfonamide accelerator, a thiuram accelerator, a dithiocarbamate accelerator and a diphenylguanidine accelerator; preferably, the thiazole accelerator is accelerator DM, preferably, the sulfonamide accelerator is accelerator CZ and / or accelerator NS, preferably, the thiuram accelerator is accelerator TMTD, preferably, the dithiocarbamate accelerator is accelerator PX, and preferably, the diphenylguanidine accelerator is accelerator DPG.

[0013] According to another aspect of the present invention, there is provided a rubber compound for a tire sidewall, which is obtained by mixing a rubber composition, wherein the rubber composition is the rubber composition described above.

[0014] According to another aspect of the present invention, there is provided a method for preparing the above-mentioned rubber compound for tire sidewalls, the preparation method comprising: step S1, sequentially performing a first-stage mixing and a first batch of mixing of raw materials including a first rubber, a first carbon black, an activator, an antioxidant and an auxiliary agent to obtain a first-stage masterbatch; step S2, sequentially performing a second-stage mixing and a second batch of mixing of raw materials including a second rubber, a second carbon black and a first-stage masterbatch to obtain a second-stage masterbatch; and step S3, sequentially performing a final mixing and a third batch of mixing of raw materials including a second-stage masterbatch, a vulcanizing agent and an accelerator to obtain a rubber compound for tire sidewalls.

[0015] Furthermore, the above-mentioned step S1 includes: performing a first mixing of the first carbon black and the first rubber to obtain a first mixed material, and performing a first mixing and a first rubber discharge of a mixture including the first mixed material and an active agent, an antioxidant and an auxiliary agent in sequence to obtain a masterbatch; the first mixing time is 1 to 4 minutes, and / or the first mixing time is 2 to 6 minutes, and / or the temperature of the first rubber discharge is 140 to 160°C.

[0016] Further, the above step S2 includes: leaving one stage of masterbatch for 2 to 8 hours and then performing two-stage mixing; and / or, the time for the two-stage mixing is 2 to 6 minutes, and / or the temperature of the second batch of rubber is 140 to 160°C; and / or, in the above step S3, the second stage of masterbatch is left for 2 to 8 hours and then final mixing; and / or, the time for the final mixing is 2 to 6 minutes, and / or, the temperature of the third batch of rubber is 80 to 110°C; and / or, the mass ratio of the first carbon black to the second carbon black is 1 to 2:1, and / or, the first rubber is natural rubber, the second rubber is polyisoprene rubber and / or polybutadiene rubber, and the mass ratio of the first rubber to the second rubber is 1 to 4:1.

[0017] Further, in the above step S1, when the Mooney viscosity ML1+4@125°C of the first stage of masterbatch is 65-70, the first stage of masterbatch is subjected to the first stage of refining, and the time of the first stage of refining is 2-6 min; when the Mooney viscosity ML1+4@125°C of the first stage of masterbatch is 71-90, the first stage of masterbatch is subjected to the second stage of refining, and the time of the second stage of refining is 2-6 min; and / or, in the above step S2, when the Mooney viscosity ML1+4@125°C of the second stage of masterbatch is 55-65, the second stage of masterbatch is subjected to the second stage of refining, and the time of the second stage of refining is 2-6 min.

[0018] By applying the technical solution of the present invention, compared with the existing giant engineering machinery tire sidewall rubber composition, the p-phenylenediamine antioxidant in the tire sidewall rubber composition of the present application has good anti-aging performance and does not produce highly toxic quinone products. When the existing p-phenylenediamine antioxidant reacts with ozone, it is easy to generate p-benzoquinone on the benzene ring of p-phenylenediamine. This is because the remaining four positions on the benzene ring of p-phenylenediamine after the substitution of the amine group are in a relatively electron-rich activation state, and thus are easily oxidized by ozone or oxygen in the atmosphere to p-benzoquinone with higher toxicity. The present application uses the p-phenylenediamine antioxidant of the above structure, which can replace and end-cap the benzene ring of p-phenylenediamine so that there is no simultaneous exposure of the para position, thereby preventing the p-phenylenediamine antioxidant from being oxidized to generate p-benzoquinone. The antioxidant A of the structure shown in formula I and the antioxidant B of the structure shown in formula II have different substitution positions and different chain hydrocarbon groups or alicyclic hydrocarbon groups on the benzene ring of p-phenylenediamine. Through the synergistic effect of antioxidant A and antioxidant B, the risk of rubber spray bloom can be reduced, thereby further improving the ability of rubber to resist erosion by aging factors such as ultraviolet rays, oxygen and heat, thereby ensuring that the tire sidewall maintains good performance for a long time. The rubber compound prepared by the rubber composition composed of the above-mentioned weight range has excellent physical properties and aging resistance, and is more suitable for tire sidewall production. In addition, by carrying out toxicity detection on rubber residues, no highly toxic quinone products were detected after detection. Therefore, the rubber composition for tire sidewalls of the present application is environmentally friendly and non-toxic, and has good environmental performance. DETAILED DESCRIPTION

[0019] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0020] As analyzed in the background technology of the present application, there are problems in the prior art such as ozone aging of p-phenylenediamine antioxidants in rubber compositions to generate highly toxic quinone products. In order to solve the above problems, the present application provides a rubber composition for tire sidewalls, a rubber compound for tire sidewalls and a preparation method thereof.

[0021] In a typical embodiment of the present application, a rubber composition for a tire sidewall is provided, which comprises, by weight, 100 parts of rubber, 30 to 70 parts of carbon black, 2 to 20 parts of an antioxidant, 1 to 15 parts of an activator, 0.5 to 4 parts of a vulcanizing agent, 0.5 to 6 parts of an accelerator, and 1 to 10 parts of an auxiliary agent; the antioxidant comprises a p-phenylenediamine antioxidant, the p-phenylenediamine antioxidant being an antioxidant A having a structure shown in formula I and / or an antioxidant B having a structure shown in formula II,

[0022] Compared with the existing giant engineering machinery tire sidewall rubber composition, the p-phenylenediamine antioxidant in the tire sidewall rubber composition of the present application has good anti-aging performance and does not produce highly toxic quinone products. When the existing p-phenylenediamine antioxidant reacts with ozone, it is easy to generate p-benzoquinone on the benzene ring of p-phenylenediamine. This is because the remaining four positions on the benzene ring of p-phenylenediamine after the substitution of the amine group are in a relatively electron-rich activation state, and thus are easily oxidized by ozone or oxygen in the atmosphere to p-benzoquinone with higher toxicity. The present application uses the p-phenylenediamine antioxidant with the above structure, which can replace and end-cap the benzene ring of p-phenylenediamine so that there is no simultaneous exposure of the para position, thereby preventing the p-phenylenediamine antioxidant from being oxidized to generate p-benzoquinone. The antioxidant A of the structure shown in formula I and the antioxidant B of the structure shown in formula II have different substitution positions and different chain hydrocarbon groups or alicyclic hydrocarbon groups on the benzene ring of p-phenylenediamine. Through the synergistic effect of antioxidant A and antioxidant B, the risk of rubber spray bloom can be reduced, thereby further improving the ability of rubber to resist erosion by aging factors such as ultraviolet rays, oxygen and heat, thereby ensuring that the tire sidewall maintains good performance for a long time. The rubber compound prepared by the rubber composition composed of the above-mentioned weight range has excellent physical properties and aging resistance, and is more suitable for tire sidewall production. In addition, by carrying out toxicity detection on rubber residues, no highly toxic quinone products were detected after detection. Therefore, the rubber composition for tire sidewalls of the present application is environmentally friendly and non-toxic, and has good environmental performance.

[0023] In order to further improve the anti-aging performance and processing performance of the rubber composition and better apply it to the tire sidewall, in one embodiment of the present application, the rubber composition includes, by weight: 100 parts of rubber, 35-60 parts of carbon black, 3-15 parts of antioxidant, 2-8 parts of activator, 1-3 parts of vulcanizer, 1-2.5 parts of accelerator and 3-8 parts of auxiliary agent; and / or the specific surface area of ​​carbon black is 20-400m 2 / g, preferably 20 to 200 m 2 / g, more preferably 50 to 150 m 2 / g.

[0024] The specific surface area of ​​carbon black is preferably within the above range, which contributes to improving the fatigue resistance of the rubber composition for tire sidewalls.

[0025] In one embodiment of the present application, when the paraphenylenediamine antioxidant is a combination of antioxidant A and antioxidant B, the mass ratio of antioxidant A to antioxidant B is 1 to 5:1; and / or the antioxidant also includes protective wax and / or antioxidant RD.

[0026] It is preferred that the p-phenylenediamine antioxidant is a combination of antioxidant A and antioxidant B, and controlling the mass ratio of antioxidant A to antioxidant B within the above range helps to further improve the synergistic effect of antioxidant A and antioxidant B, thereby further improving the ability of rubber to resist erosion by aging factors such as ultraviolet rays, oxygen and heat, thereby ensuring that the tire can still maintain good performance after long-term use.

[0027] In one embodiment of the present application, the rubber is selected from any one or more of natural rubber, polyisoprene rubber and polybutadiene rubber; preferably, the rubber is a combination of natural rubber and polyisoprene rubber; preferably, the rubber is a combination of natural rubber and polybutadiene rubber; and / or, the molecular weight of the rubber is 1000 to 400 million, preferably 5000 to 300 million, and more preferably 10000 to 8 million.

[0028] The rubber is preferably a combination of natural rubber and polyisoprene rubber or a combination of natural rubber and polybutadiene rubber, which contributes to improving the strength and fatigue resistance of the rubber composition for tire sidewalls.

[0029] In one embodiment of the present application, the auxiliary agent is a coupling agent and / or a softener; wherein the coupling agent is selected from any one or more of bis(triethoxypropylsilane) tetrasulfide, bis(triethoxypropylsilane) disulfide, 3-thiocyanatopropyl-triethoxysilane, γ-mercaptopropyl-trimethoxysilane, zirconate coupling agent, phthalate coupling agent and nitro coupling agent; and / or, based on 100 parts by weight of rubber, the amount of the coupling agent is 0 to 8 parts by weight, preferably 0 to 4 parts by weight; and / or, the softener is oil and / or resin; the oil is aromatic oil, the resin is tackifying resin and / or tear-resistant resin, preferably the tackifying resin is selected from any one or more of tert-butylphenolic resin, C5 petroleum resin and C9 petroleum resin, and preferably the tear-resistant resin is rosin and / or C9 mixed resin; and / or, based on 100 parts by weight of rubber, the amount of softener is 0 to 20 parts by weight, preferably 0 to 10 parts by weight; and / or, the activator is zinc oxide and / or stearic acid; and / or, the vulcanizing agent is selected from any one or more of sulfur, sulfur donors and peroxides; and / or, the accelerator is selected from any one or more of thiazole accelerators, sulfonamide accelerators, thiuram accelerators, dithiocarbamate accelerators and diphenylguanidine accelerators; preferably, the thiazole accelerator is accelerator DM, preferably, the sulfonamide accelerator is accelerator CZ and / or accelerator NS, preferably, the thiuram accelerator is accelerator TMTD, preferably, the dithiocarbamate accelerator is accelerator PX, and preferably, the diphenylguanidine accelerator is accelerator DPG.

[0030] The type and amount of the coupling agent are preferably within the above ranges, which helps to reduce the melt viscosity of the rubber, thereby improving its fluidity, and further helping to improve the molding performance and processing performance of the rubber composition. The type and amount of the softener are preferably within the above ranges, which helps to adjust the softness of the rubber composition, thereby improving the processing performance of the rubber. The activator, accelerator and vulcanizing agent are preferably of the above types, which helps to accelerate the vulcanization reaction between the vulcanizing agent and the rubber molecules, forming a uniform and stable cross-linked structure, thereby helping to improve the hardness, wear resistance and tear strength of the rubber composition.

[0031] In another typical embodiment of the present application, a rubber compound for a tire sidewall is provided, which is obtained by mixing a rubber composition, and the rubber composition is the rubber composition mentioned above.

[0032] The rubber compound obtained by mixing the rubber composition is not only environmentally friendly, non-toxic and easy to process, but also has high hardness, wear resistance and tear strength, and is therefore more suitable for use on tire sidewalls.

[0033] In another typical embodiment of the present application, a method for preparing the above-mentioned rubber compound for tire sidewalls is provided, and the preparation method comprises: step S1, mixing and batching the raw materials including the first rubber, the first carbon black, the activator, the antioxidant and the auxiliary agent in a first stage, so as to obtain a first masterbatch; step S2, mixing and batching the raw materials including the second rubber, the second carbon black and the first masterbatch in a second stage, so as to obtain a second masterbatch; and step S3, mixing and batching the raw materials including the second masterbatch, the vulcanizing agent and the accelerator in a final stage, so as to obtain a rubber compound for tire sidewalls.

[0034] The present application adopts a multi-stage mixing process, and the antioxidant and part of the carbon black are added to the rubber for mixing separately, which can reduce the interference of the antioxidant on the dispersion of carbon black and improve the processing performance of the rubber. Through one-stage mixing, the first carbon black, activator, antioxidant and auxiliary agent are evenly dispersed in the first rubber to form a masterbatch with good dispersibility and plasticity, which is conducive to subsequent processing. The second carbon black and the second rubber are added to a masterbatch for two-stage mixing, which can further reduce the interference of the antioxidant on the dispersion of carbon black. Among them, the first rubber and the second rubber are added respectively for one-stage mixing and two-stage mixing, which helps carbon black to be better dispersed in the rubber. Adding vulcanizing agent and accelerator in the final mixing process can make the vulcanizing agent and accelerator fully and evenly dispersed, so as to improve the hardness, wear resistance and tear resistance of the tire sidewall mixed rubber.

[0035] In one embodiment of the present application, the above-mentioned step S1 includes: after a first mixing of the first carbon black and the first rubber, a first mixed material is obtained, and a mixture including the first mixed material, an activator, an antioxidant and an auxiliary agent is sequentially mixed and subjected to a first batch of rubber to obtain a masterbatch; the first mixing time is 1 to 4 minutes, and / or the mixing time is 2 to 6 minutes, and / or the temperature of the first batch of rubber is 140 to 160°C.

[0036] Preferably, before adding the activator, antioxidant and auxiliary agent, the first carbon black and the first rubber are first mixed and the first mixing time is controlled within the above range, which helps to improve the dispersibility of the carbon black, so that the carbon black is better dispersed in the rubber. Preferably, the time of a mixing stage and the temperature of the first rubber discharge are controlled within the above range, which helps to improve the dispersibility and plasticity of a masterbatch.

[0037] In one embodiment of the present application, the above-mentioned step S2 includes: parking a stage of masterbatch for 2 to 8 hours and then performing two-stage mixing; and / or, the time for the two-stage mixing is 2 to 8 minutes, and / or the temperature of the second row of rubber is 140 to 160°C; and / or, in the above-mentioned step S3, the second stage of masterbatch is parked for 2 to 8 hours and then final mixing is performed; and / or, the time for the final mixing is 2 to 6 minutes, and / or, the temperature of the third row of rubber is 80 to 110°C; and / or, the mass ratio of the first carbon black to the second carbon black is 1 to 2:1, and / or, the first rubber is natural rubber, the second rubber is polyisoprene rubber and / or polybutadiene rubber, and the mass ratio of the first rubber to the second rubber is 1 to 4:1.

[0038] It is preferred that the first stage of the masterbatch is parked for the above time before the second stage of mixing is carried out, and the mass ratio of the first carbon black to the second carbon black, the time of the second stage of mixing and the temperature of the second batch of rubber are controlled within the above range, which not only helps to better disperse the carbon black, but also helps to reduce the interference of the antioxidant on the dispersion of the carbon black, thereby improving the processing performance of the mixed rubber. It is preferred that the first rubber is natural rubber, the second rubber is polyisoprene rubber and / or polybutadiene rubber, and the mass ratio of the first rubber to the second rubber is controlled within the above range, which helps to improve the strength and fatigue resistance of the mixed rubber. It is preferred that the second stage of the masterbatch is parked for the above time before the final mixing is carried out, and the time of the final mixing and the temperature of the third batch of rubber are controlled within the above range, which helps to fully and evenly disperse the vulcanizer and the accelerator, thereby further improving the hardness, wear resistance and tear resistance of the mixed rubber.

[0039] In one embodiment of the present application, in the above step S1, when the Mooney viscosity ML1+4@125℃ of a masterbatch is 65-70, the first stage of refining is performed on the masterbatch, and the time of the first stage of refining is 2-6 min; when the Mooney viscosity ML1+4@125℃ of a masterbatch is 71-90, the second stage of refining is performed on the masterbatch, and the time of the second stage of refining is 2-6 min; and / or, in the above step S2, when the Mooney viscosity ML1+4@125℃ of the second stage of masterbatch is 55-65, the second stage of refining is performed on the second stage of masterbatch, and the time of the second stage of refining is 2-6 min.

[0040] By monitoring the Mooney viscosity of the first and second masterbatch and refining them when they are within the above range, it is helpful to adjust the viscosity of the rubber composition in time, so that it has good fluidity and plasticity in the subsequent mixing and molding process, and thus meet the production requirements of the tire sidewall. In particular, when the Mooney viscosity ML1+4@125℃ of the first masterbatch reaches 71-90, refining the first masterbatch in the second stage will help further improve the processing performance of the mixed rubber compared with the first stage refining.

[0041] The beneficial effects of the present application will be further illustrated below in conjunction with embodiments.

[0042] In Examples 1 to 2 and Comparative Example 1 of the present invention, the composition of the rubber composition in parts by weight is shown in Table 1. The rubber composition is used as a raw material to prepare a rubber compound using the following preparation method and apparatus:

[0043] 1. Raw materials and instruments

[0044] The first rubber is natural rubber (NR): STR20#, standard rubber.

[0045] The second rubber is polybutadiene rubber (BR): BR9000, China Petrochemical Corporation.

[0046] The first carbon black and the second carbon black: N330, Shanghai Cabot Co., Ltd.

[0047] Stearic acid: Tyco Brown Chemical (Zhangjiagang) Co., Ltd.

[0048] Zinc oxide: Shijiazhuang Hetong Chemical Co., Ltd.

[0049] Protective wax: Shandong Yanggu Huatai Chemical Co., Ltd.

[0050] Antioxidant RD: Kemai Chemical Co., Ltd.

[0051] Antioxidant 4020, Shandong Shengao Chemical Technology Co., Ltd.

[0052] Accelerator CZ: Shandong Shangshun Chemical Co., Ltd.

[0053] Sulfur: Chaoyang Tianming Industry and Trade Co., Ltd.

[0054] The chemical structure of antioxidant A is (Prepared with reference to Chinese patent application publication number CN113072741A).

[0055] The chemical structure of antioxidant B is (Prepared with reference to Chinese patent application publication number CN113072741A).

[0056] Coupling agent: bis(triethoxypropylsilane) disulfide, Nanjing Shuguang Silane Chemical Co., Ltd.

[0057] Internal mixer: specification model is XSM-1 / 10-120, manufacturer is Shanghai Kechuang Rubber & Plastic Machinery Equipment Co., Ltd.

[0058] Open mixer: After each discharge of the internal mixer, the sheets are unloaded through the open mixer. The specification model is 152.5*320, and the manufacturer is Guangdong Zhanjiang Machinery Factory.

[0059] 2. Preparation method

[0060] The first carbon black N330 was added to the natural rubber and mixed for 1 minute in the internal mixer to obtain the first mixed material. Stearic acid, zinc oxide, antioxidant and coupling agent bis(triethoxypropylsilane) disulfide were added to the first mixed material and mixed for 2 minutes and discharged for the first time at 150°C to obtain the first masterbatch. When the Mooney viscosity ML1+4@125°C of the first masterbatch was 65, the first masterbatch was remixed for 2 minutes. After the first masterbatch was parked for 4 hours, the second carbon black N330, polybutadiene rubber and the first masterbatch were mixed for 2 minutes and discharged for the second time at 150°C in the internal mixer to obtain the second masterbatch. When the Mooney viscosity ML1+4@125°C of the second masterbatch was 55, the second masterbatch was remixed for 2 minutes. After the second-stage masterbatch was left for 4 hours, the second-stage masterbatch, the vulcanizing agent and the accelerator were successively subjected to final mixing for 2 minutes and the third mixing at 100° C. in an internal mixer to obtain a mixed rubber.

[0061] Example 3

[0062] The difference from Example 1 is that the total weight parts of natural rubber and polybutadiene rubber is 100 parts, the mass ratio of natural rubber to polybutadiene rubber is 4:1, and finally a mixed rubber is obtained.

[0063] Example 4

[0064] The difference from Example 1 is that the first rubber and the second rubber are polybutadiene rubber, the total weight parts are 100 parts, the mass ratio of natural rubber to polybutadiene rubber is 5:1, and finally a mixed rubber is obtained.

[0065] Example 5

[0066] The difference from Example 1 is that the p-phenylenediamine antioxidant is a combination of antioxidant A and antioxidant B, the total weight parts are 3 parts, the mass ratio of antioxidant A to antioxidant B is 1:1, and finally a mixed rubber is obtained.

[0067] Example 6

[0068] The difference from Example 1 is that the p-phenylenediamine antioxidant is a combination of antioxidant A and antioxidant B, the total weight parts are 3 parts, the mass ratio of antioxidant A to antioxidant B is 5:1, and finally a mixed rubber is obtained.

[0069] Example 7

[0070] The difference from Example 1 is that the p-phenylenediamine antioxidant is a combination of antioxidant A and antioxidant B, the total weight parts are 3 parts, the mass ratio of antioxidant A to antioxidant B is 6:1, and finally a mixed rubber is obtained.

[0071] Example 8

[0072] The difference from Example 1 is that when the Mooney viscosity ML1+4@125°C of a masterbatch is 70, the masterbatch is first re-milled for 6 minutes to finally obtain a mixed rubber.

[0073] Example 9

[0074] The difference from Example 1 is that when the Mooney viscosity ML1+4@125°C of the first-stage masterbatch is 71, the first-stage masterbatch is subjected to second-stage refining for 6 minutes to finally obtain a mixed rubber.

[0075] Example 10

[0076] The difference from Example 1 is that when the Mooney viscosity ML1+4@125°C of the first-stage masterbatch is 90, the first-stage masterbatch is subjected to second-stage refining for 6 minutes to finally obtain a mixed rubber.

[0077] Embodiment 11

[0078] The difference from Example 1 is that when the Mooney viscosity ML1+4@125°C of the first-stage masterbatch is 100, the second-stage mixing is directly carried out for 6 minutes after being parked for 4 hours to finally obtain a mixed rubber.

[0079] Example 12

[0080] The difference from Example 1 is that when the Mooney viscosity ML1+4@125°C of the second-stage masterbatch is 65, the second-stage masterbatch is re-milled for 6 minutes to finally obtain a mixed rubber.

[0081] Example 13

[0082] The difference from Example 1 is that when the Mooney viscosity ML1+4@125°C of the second-stage masterbatch is 70, the final mixing is directly carried out for 6 minutes after being parked for 4 hours to obtain a mixed rubber.

[0083] Comparative Example 1

[0084] Carbon black N330 was added to natural rubber and polybutadiene rubber, mixed in an internal mixer for 1 minute, and then stearic acid, zinc oxide, antioxidant and additive were added and mixed for 2 minutes and discharged at 150°C to obtain a masterbatch. After the masterbatch was left for 4 hours, the accelerator and vulcanizer were added to the masterbatch, mixed in an internal mixer for 2 minutes, and then discharged to obtain a mixed rubber.

[0085] Test method:

[0086] Flat vulcanizing press: model specification is XLB-D600*600, manufacturer is Zhejiang Huzhou Dongfang Machinery Co., Ltd.

[0087] Mooney viscosity: Determined in accordance with “GB / T 1232.1-2016 Unvulcanized rubber using disc shear viscometer - Part 1: Determination of Mooney viscosity”.

[0088] Hardness: Determined in accordance with GB / T 531.1-2008 Test method for indentation hardness of vulcanized rubber or thermoplastic rubber Part 1: Shore durometer method (Shore hardness)

[0089] Tensile strength, elongation at break, and modulus of tensile stress: Determined in accordance with GB / T 528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber.

[0090] Tear strength: Determined in accordance with GB / T 529-2008 Determination of tear strength of vulcanized rubber or thermoplastic rubber (trouser-shaped, right-angled and crescent-shaped test specimens)

[0091] Rebound resilience: Determined in accordance with GB / T 1681-2009 Determination of rebound resilience of vulcanized rubber.

[0092] Compression heat generation: Determined in accordance with GB / T 1687.3-2016 Determination of temperature rise and fatigue resistance of vulcanized rubber in flexure test Part 3: Compression flexure test (constant strain type)

[0093] Hot air aging performance: According to GB / T 3512-2014 Hot air accelerated aging and heat resistance test for vulcanized rubber or thermoplastic rubber, the vulcanized rubber was aged in hot air at 100°C for 72h.

[0094] The mixed rubbers of the above embodiments and comparative examples were left standing for 4 hours and then vulcanized for 30 minutes at 150° C. using a flat vulcanizer to obtain vulcanized rubbers, which were then tested for performance. The test results are shown in Tables 2 and 3.

[0095] Table 1

[0096]

[0097]

[0098] Table 2

[0099]

[0100]

[0101] Table 3

[0102]

[0103] After aging, the vulcanized rubber of the above example was extracted, and the extract was detected by ultra-high performance liquid chromatography-high resolution tandem mass spectrometry (UPLC-HRMS / MS), and no quinone compounds were detected; while quinone compounds were detected in the vulcanized rubber of comparative example 1. Therefore, the p-phenylenediamine antioxidant in the rubber composition for tire sidewalls of the present invention does not produce highly toxic quinone products, and is environmentally friendly and non-toxic.

[0104] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0105] Compared with the existing giant engineering machinery tire sidewall rubber composition, the p-phenylenediamine antioxidant in the tire sidewall rubber composition of the present application has good anti-aging performance and does not produce highly toxic quinone products. When the existing p-phenylenediamine antioxidant reacts with ozone, it is easy to generate p-benzoquinone on the benzene ring of p-phenylenediamine. This is because the remaining four positions on the benzene ring of p-phenylenediamine after the substitution of the amine group are in a relatively electron-rich activation state, and thus are easily oxidized by ozone or oxygen in the atmosphere to p-benzoquinone with higher toxicity. The present application uses the p-phenylenediamine antioxidant with the above structure, which can replace and end-cap the benzene ring of p-phenylenediamine so that there is no simultaneous exposure of the para position, thereby preventing the p-phenylenediamine antioxidant from being oxidized to generate p-benzoquinone. The antioxidant A of the structure shown in formula I and the antioxidant B of the structure shown in formula II have different substitution positions and different chain hydrocarbon groups or alicyclic hydrocarbon groups on the benzene ring of p-phenylenediamine. Through the synergistic effect of antioxidant A and antioxidant B, the risk of rubber spray bloom can be reduced, thereby further improving the ability of rubber to resist erosion by aging factors such as ultraviolet rays, oxygen and heat, thereby ensuring that the tire sidewall maintains good performance for a long time. The rubber compound prepared by the rubber composition composed of the above-mentioned weight range has excellent physical properties and aging resistance, and is more suitable for tire sidewall production. In addition, by carrying out toxicity detection on rubber residues, no highly toxic quinone products were detected after detection. Therefore, the rubber composition for tire sidewalls of the present application is environmentally friendly and non-toxic, and has good environmental performance.

[0106] The above are only embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A rubber composition for tire sidewalls, characterized in that: In parts by weight, the rubber composition comprises: 100 parts of rubber; 30-70 parts of carbon black; 2 to 20 parts of antioxidant; 1 to 15 parts of active agent; 0.5 to 4 parts of vulcanizing agent; 0.5 to 6 parts of an accelerator; and 1 to 10 parts of additives; The antioxidant includes a p-phenylenediamine antioxidant, and the p-phenylenediamine antioxidant is an antioxidant A with a structure shown in formula I and / or an antioxidant B with a structure shown in formula II.

2. The rubber composition according to claim 1, characterized in that In parts by weight, the rubber composition comprises: 100 parts of the rubber; 35 to 60 parts of the carbon black; 3 to 15 parts of the antioxidant; 2 to 8 parts of the active agent; 1 to 3 parts of the vulcanizing agent; 1 to 2.5 parts of the accelerator; and 3 to 8 parts of the auxiliary agent; And / or, the specific surface area of ​​the carbon black is 20 to 400 m 2 / g, preferably 20 to 200 m 2 / g, more preferably 50 to 150 m 2 / g.

3. The rubber composition according to claim 1 or 2, characterized in that: When the p-phenylenediamine antioxidant is a combination of the antioxidant A and the antioxidant B, the mass ratio of the antioxidant A to the antioxidant B is 1 to 5:1; and / or the antioxidant further includes protective wax and / or antioxidant RD.

4. The rubber composition according to any one of claims 1 to 3, characterized in that The rubber is selected from any one or more of natural rubber, polyisoprene rubber and polybutadiene rubber; preferably, the rubber is a combination of natural rubber and polyisoprene rubber; preferably, the rubber is a combination of natural rubber and polybutadiene rubber; and / or, the molecular weight of the rubber is 1000 to 400 million, preferably 5000 to 300 million, and more preferably 10000 to 8 million.

5. The rubber composition according to any one of claims 1 to 4, characterized in that The auxiliary agent is a coupling agent and / or a softener; Wherein, the coupling agent is selected from any one or more of bis(triethoxypropylsilane)tetrasulfide, bis(triethoxypropylsilane)disulfide, 3-thiocyanatopropyl-triethoxysilane, γ-mercaptopropyl-trimethoxysilane, zirconate coupling agent, phthalate coupling agent and nitro coupling agent; and / or, based on 100 parts by weight of the rubber, the amount of the coupling agent is 0 to 8 parts by weight, preferably 0 to 4 parts by weight; And / or, the softener is oil and / or resin; the oil is aromatic oil, the resin is tackifying resin and / or tear-resistant resin, preferably the tackifying resin is selected from any one or more of tert-butyl phenolic resin, C5 petroleum resin and C9 petroleum resin, preferably the tear-resistant resin is rosin and / or C9 mixed resin; and / or, based on 100 parts by weight of the rubber, the amount of the softener is 0 to 20 parts by weight, preferably 0 to 10 parts by weight; And / or, the active agent is zinc oxide and / or stearic acid; And / or, the vulcanizing agent is selected from any one or more of sulfur, sulfur donors and peroxides; And / or, the accelerator is selected from any one or more of thiazole accelerators, sulfonamide accelerators, thiuram accelerators, dithiocarbamate accelerators and diphenylguanidine accelerators; preferably, the thiazole accelerator is accelerator DM, preferably, the sulfonamide accelerator is accelerator CZ and / or accelerator NS, preferably, the thiuram accelerator is accelerator TMTD, preferably, the dithiocarbamate accelerator is accelerator PX, and preferably, the diphenylguanidine accelerator is accelerator DPG.

6. A rubber compound for tire sidewalls, obtained by mixing a rubber composition, characterized in that: The rubber composition is the rubber composition according to any one of claims 1 to 5.

7. A method for preparing the rubber compound for tire sidewalls according to claim 6, characterized in that: The preparation method comprises: Step S1, sequentially performing a first mixing and a first rubber removal on raw materials including a first rubber, a first carbon black, an activator, an antioxidant and an auxiliary agent to obtain a masterbatch; Step S2, sequentially performing two-stage mixing and second-stage mixing of the raw materials including the second rubber, the second carbon black and the first-stage masterbatch to obtain a second-stage masterbatch; and Step S3, subjecting the raw materials including the second-stage masterbatch, the vulcanizing agent and the accelerator to final mixing and third mixing in sequence to obtain the mixed rubber for the tire sidewall.

8. The preparation method according to claim 7, characterized in that: The step S1 comprises: performing a first mixing on the first carbon black and the first rubber to obtain a first mixed material, and performing the first mixing and the first rubber removal on a mixture including the first mixed material, the activating agent, the antioxidant and the auxiliary agent in sequence to obtain the first masterbatch; The first mixing time is 1 to 4 minutes, and / or the first mixing time is 2 to 6 minutes, and / or the first debonding temperature is 140 to 160°C.

9. The preparation method according to claim 7 or 8, characterized in that: The step S2 comprises: placing the first batch of masterbatch for 2 to 8 hours before performing the second batch of mixing; and / or the second batch of masterbatch lasts for 2 to 6 minutes, and / or the temperature of the second batch of masterbatch is 140 to 160° C.; And / or, in the step S3, the second stage masterbatch is left for 2 to 8 hours before the final refining; and / or, the final refining time is 2 to 6 minutes, and / or, the temperature of the third batch of masterbatch is 80 to 110°C; And / or, the mass ratio of the first carbon black to the second carbon black is 1-2:1, and / or, the first rubber is natural rubber, the second rubber is polyisoprene rubber and / or polybutadiene rubber, and the mass ratio of the first rubber to the second rubber is 1-4:

1.

10. The preparation method according to any one of claims 7 to 9, characterized in that: In the step S1, when the Mooney viscosity ML1+4@125°C of the masterbatch is 65-70, the masterbatch is subjected to a first re-milling, and the time of the first re-milling is 2-6 minutes; When the Mooney viscosity ML1+4@125°C of the first stage masterbatch is 71 to 90, the first stage masterbatch is subjected to second-stage refining, and the second-stage refining time is 2 to 6 minutes; And / or, in the step S2, when the Mooney viscosity ML1+4@125°C of the second-stage masterbatch is 55-65, the second-stage masterbatch is subjected to a second-stage re-milling, and the time of the second-stage re-milling is 2-6 minutes.

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