Rubber master batch for conveyor belt cover rubber, preparation method of rubber master batch and rubber nano composite material

Abstract

The invention relates to a rubber master batch, in particular to a rubber master batch for conveyor belt cover rubber, a preparation method of the rubber master batch and a rubber nanocomposite. The wet mixing method provided by the invention comprises the following steps: modifying white carbon black by using fatty alcohol-polyoxyethylene ether and a silane coupling agent at the same time, mixing the modified white carbon black with rubber latex in a dispersion liquid, and carrying out film paving and air drying to obtain the rubber master batch. According to the rubber master batch obtained by the method, the white carbon black filler is uniformly dispersed in the master batch, so that the wear resistance and rolling resistance of the master batch can be effectively improved, and the rubber master batch can be used for preparing a rubber nano composite material with excellent wear resistance and rolling resistance. The technical problems that white carbon black is not uniformly dispersed and agglomerated and is lost when the masterbatch is prepared by adopting an existing wet-process mixing process are solved.

Description

Technical Field

[0001] The present invention relates to a rubber masterbatch, and more particularly, to a rubber masterbatch for conveyor belt cover rubber, its preparation method, and a rubber nanocomposite material. Background Art

[0002] Most rubber products mainly adopt dry mixing technology so far, that is, solid rubber, reinforcing fillers, softening oil, and various additives are dry mixed into a masterbatch in a mixer, then processed and formed, and finally vulcanized into rubber products. Dry mixing consumes a large amount of energy, pollutes the environment, and endangers the health of workers; there are also many disadvantages such as low intermittent production efficiency and different batch qualities. Therefore, improving the mixing method has always been the goal pursued by the rubber processing industry.

[0003] In the rubber industry, fillers are used to improve performance or reduce costs. Carbon black and silica are the most widely used fillers and are also commonly used reinforcing fillers in elastomer formulations. Compared with carbon black, silica is a reinforcing filler that does not rely on petroleum resources. It has a large number of highly polar silanol groups and a very high surface energy on its surface. Using silica instead of carbon black as the main reinforcing filler can significantly reduce the rolling resistance and improve the wet skid resistance. However, due to its low nanoscale size and high specific surface area, silica is easily aggregated into larger particles and agglomerated, resulting in poor compatibility between it and the rubber matrix.

[0004] To solve the problem of difficult dispersion of silica, the commonly used solution is to modify silica with a silane coupling agent, reduce the number of surface hydroxyl groups, and introduce reactive groups to enhance its interaction with the rubber matrix. Among them, coupling agents such as γ-glycidoxypropyltrimethoxysilane (KH560), KH560 octadecylamine (KH560ODA), bis(γ-triethoxysilylpropyl)tetrasulfide (Si69), γ-(methacryloyloxy)propyltrimethoxysilane (KH570) can modify fumed silica to prepare silica / NR composites modified with different silane coupling agents. The research results show that the above coupling agents have obvious modification effects on silica, the dispersion of silica is significantly improved, and the vulcanization properties, mechanical properties, and processing properties of the composites are all improved.

[0005] In recent years, there have also been reports on improving the dispersion performance of silica by adopting a wet mixing process. For the silica / rubber composite system, wet mixing usually adopts the method of emulsion blending. Specifically, it is to disperse silica in water and mix it with rubber latex, and then obtain a masterbatch through a flocculation process. However, when preparing high-loading silica composites by this method, too much silica will cause premature demulsification of the rubber latex, resulting in problems of silica loss and poor dispersion. Summary of the Invention

[0006] In order to solve the technical problems of uneven dispersion, agglomeration and loss of white carbon black existing in the preparation of masterbatch by the existing wet mixing process, the present invention provides a new wet mixing preparation method for rubber masterbatch. The wet mixing method provided by the present invention uses fatty alcohol polyoxyethylene ether and silane coupling agent to modify white carbon black at the same time, mixes the modified white carbon black dispersion liquid with rubber latex, and obtains rubber masterbatch by means of film laying and air drying. The rubber masterbatch obtained by this method has uniform dispersion of white carbon black filler in the masterbatch, can effectively improve the abrasion resistance and rolling resistance of the masterbatch, and can be used for the preparation of rubber nanocomposites with excellent abrasion resistance and rolling resistance.

[0007] One of the objects of the present invention is to provide a preparation method for rubber masterbatch. The preparation method includes the following steps:

[0008] Step 1: Add white carbon black and dispersion medium into a grinding device for grinding, and then add silane coupling agent and fatty alcohol polyoxyethylene ether into the grinding device to continue grinding to obtain a modified white carbon black slurry;

[0009] Step 2: Mix rubber with a solvent and dissolve to obtain a rubber solution;

[0010] Step 3: Mix the modified white carbon black slurry and the rubber solution under stirring conditions to obtain a masterbatch mixed slurry;

[0011] Step 4: Perform film laying and drying on the masterbatch mixed slurry to obtain the rubber masterbatch.

[0012] Silane coupling agent is the most commonly used surface modifier for white carbon black in industry. Its grafting effect on the surface of white carbon black nanoparticles can promote the attachment of white carbon black particles to the rubber matrix, thereby improving the mechanical properties of the composite material. Fatty alcohol polyoxyethylene ether acts on white carbon black, by reducing the hydroxyl density on the surface of white carbon black, changing it from hydrophilic to hydrophobic, thereby improving the compatibility between white carbon black and the rubber matrix and the dispersion of white carbon black in the rubber matrix.

[0013] In Step 1, "adding a silane coupling agent and fatty alcohol polyoxyethylene ether into the grinding equipment and continuing grinding" means that the white carbon black is modified by using a silane coupling agent and fatty alcohol polyoxyethylene ether simultaneously, which is a one-step modification method; it is different from the existing step-by-step two-step modification process of "first modifying the white carbon black with a silane coupling agent and then adding fatty alcohol polyoxyethylene ether to modify the white carbon black". According to the experimental results, compared with the existing step-by-step two-step modification method, the one-step modification method of "adding a silane coupling agent and fatty alcohol polyoxyethylene ether into the colloid mill and continuing grinding" in the present invention can obtain a rubber masterbatch with better dispersion of white carbon black and low loss of white carbon black. When AEO-9 and Si69 are used simultaneously, the coupling agent can be relatively stably dispersed in the solvent. Therefore, under certain conditions, the active sites that the dispersed coupling agent can contact with the white carbon black increase, and finally it is expected to obtain pre-modified white carbon black with excellent performance. In addition, AEO-9 can achieve chemical grafting by combining with the exposed hydroxyl groups on the surface of silica through its terminal hydroxyl groups, and at the same time, it can fully cover the surface of silica through the hydrogen bond interaction between the polyether structure and the hydroxyl groups on the surface of silica, significantly reducing the amount of exposed hydroxyl groups on the surface of silica, weakening the self-aggregation ability of silica, thereby reducing its particle size and improving its dispersion in the polymer.

[0014] Further experimental studies found that the change in the dosage ratio of the silane coupling agent and fatty alcohol polyoxyethylene ether will have an obvious impact on the dispersion of white carbon black. Specifically, compared with other dosage ratios of the silane coupling agent and fatty alcohol polyoxyethylene ether, when the weight ratio of the silane coupling agent and fatty alcohol polyoxyethylene ether is 9:1 - 15, the dispersion of white carbon black in the prepared rubber masterbatch is better; when the weight ratio of the silane coupling agent and fatty alcohol polyoxyethylene ether is 9:3 - 12, the dispersion of white carbon black in the prepared rubber masterbatch is further improved.

[0015] In addition, experimental studies found that too high a grinding temperature in Step 1 will affect the amount of white carbon black filler filled into the rubber, and thus lead to the loss of white carbon black filler. Therefore, to further reduce the loss of white carbon black filler in the rubber masterbatch, the present invention limits the grinding temperature in Step 1 to 5 - 30°C, preferably 5 - 10°C. In Step 3, the stirring speed is also an important parameter. Too low a stirring speed will cause uneven dispersion of white carbon black in the rubber, weakening the reinforcing effect on the rubber masterbatch and deteriorating the performance. Too high a stirring speed will cause the mixed liquid to overflow the container, resulting in losses. Therefore, the present invention limits the stirring speed in Step 3 to 1000 - 3000 r / min, preferably 1000 - 2000 r / min.

[0016] In Step 4, the masterbatch mixed slurry is not subjected to flocculation or steam azeotropic treatment, but directly undergoes "film laying and drying" to obtain the rubber masterbatch. The experimental results prove that, compared with directly performing "film laying and drying" on the "flocculation or steam azeotropic" masterbatch mixed slurry, it can reduce the loss of silica filler and prevent silica agglomeration, further improving the dispersion of silica.

[0017] The key step of the present invention lies in the thickness of the film laid during the film laying and drying in Step 4. If the film laying thickness is too thin, it is likely to cause the precipitation of silica filler or uneven dispersion of the filler in the rubber; if the film laying thickness is too thick, it will affect the drying efficiency and drying effect, resulting in a situation where the surface of the rubber masterbatch is dry while the inside is not dry, and there will be a small amount of agglomeration of silica in the rubber masterbatch. Therefore, the present invention limits the film laying thickness in Step 4 to 1 - 10 mm, preferably 3 - 5 mm.

[0018] The grinding equipment can be a colloid mill.

[0019] Among them, the present invention provides a specific solution: A method for preparing a rubber masterbatch, comprising:

[0020] Step 1: Add silica and a dispersion medium to a colloid mill and grind for 25 - 35 min, then add a silane coupling agent and fatty alcohol polyoxyethylene ether to the colloid mill and continue grinding for 25 - 35 min to obtain a modified silica slurry; control the grinding temperature at 5 - 10 °C;

[0021] Step 2: Mix rubber with a solvent and dissolve to obtain a rubber solution;

[0022] Step 3: Mix the modified silica slurry and the rubber solution under stirring conditions of 1000 - 2000 r / min for 25 - 35 min to obtain a masterbatch mixed slurry;

[0023] Step 4: Lay a film on the masterbatch mixed slurry, with the film laying thickness being 3 - 5 mm, and obtain the rubber masterbatch after blowing drying.

[0024] The second object of the present invention is to provide a rubber masterbatch. The rubber masterbatch is prepared by the preparation method described in the first object of the present invention.

[0025] Compared with the masterbatch prepared by the existing wet mixing process, for the rubber masterbatch obtained by the method of the present invention, the silica filler is evenly dispersed in the masterbatch, which can effectively improve the abrasion resistance and rolling resistance of the masterbatch, and can be used to prepare rubber nanocomposites with excellent abrasion resistance and rolling resistance.

[0026] The present invention also provides a rubber masterbatch for preparing a conveyor belt cover rubber with excellent abrasion resistance and rolling resistance performance. The rubber masterbatch that can be used for the conveyor belt cover rubber is prepared from raw materials including the following components by the preparation method described in one of the invention objects; the components and parts by weight are as follows:

[0027] 100 parts by weight of rubber;

[0028] 1000 - 2000 parts by weight of solvent, preferably 1250 - 1667 parts by weight;

[0029] 30 - 150 parts by weight of white carbon black, preferably 40 - 50 parts by weight;

[0030] 300 - 3000 parts by weight of dispersion medium, preferably 500 - 650 parts by weight;

[0031] 0.1 - 10 parts by weight of silane coupling agent, preferably 4 - 6 parts by weight;

[0032] 0.1 - 10 parts by weight of fatty alcohol polyoxyethylene ether, preferably 2 - 6 parts by weight;

[0033] The rubber is composed of cis - 1,4 - polybutadiene rubber and natural rubber; based on 100 parts by weight of rubber, 70 - 100 parts by weight of cis - 1,4 - polybutadiene rubber and 30 - 0 parts by weight of natural rubber; preferably, 80 - 90 parts by weight of cis - 1,4 - polybutadiene rubber and 20 - 10 parts by weight of natural rubber.

[0034] The solvent needs to be able to dissolve three substances: white carbon black, cis - 1,4 - polybutadiene rubber, and natural rubber, and at the same time needs to meet the requirements of strong volatility, low boiling point, and low toxicity. The solvent can be selected from any solvent that can meet the above requirements; preferably cyclohexane.

[0035] The dispersion medium needs to be able to dissolve three substances: white carbon black, cis - 1,4 - polybutadiene rubber, and natural rubber, and at the same time needs to meet the requirements of strong volatility, low boiling point, and low toxicity. The dispersion medium can be selected from any substance that can meet the above requirements; preferably cyclohexane. The dispersion medium and the solvent can be selected from the same substance; they can also be selected from different substances. In some embodiments disclosed in the present invention, both the dispersion medium and the solvent are selected as cyclohexane. Compared with other substances that can meet the conditions of "able to dissolve three substances: white carbon black, cis - 1,4 - polybutadiene rubber, and natural rubber, and at the same time having strong volatility, low boiling point, and low toxicity", choosing cyclohexane as the solvent and dispersion substance results in better dispersion of white carbon black in the obtained rubber masterbatch.

[0036] The silane coupling agent may be selected from one or more of bis(γ-triethoxysilylpropyl)tetrasulfide (Si69), bis(3-triethoxysilylpropyl)disulfide (Si75), γ-mercaptopropyltriethoxysilane (KH-580), and γ-mercaptopropyltrimethoxysilane (KH-590).

[0037] The fatty alcohol polyoxyethylene ether may be selected from one or more of AEO-3, AEO-5, AEO-7, AEO-9, and AEO-11.

[0038] A third object of the present invention is to provide a rubber nanocomposite. The rubber nanocomposite is prepared by mixing and kneading using the rubber masterbatch described in the second object of the present invention as the masterbatch.

[0039] Specifically, the present invention provides a rubber nanocomposite that can be used to prepare a conveyor belt cover rubber having excellent abrasion resistance and rolling resistance. The rubber nanocomposite that can be used for the conveyor belt cover rubber is prepared by mixing and kneading raw materials including the following components;

[0040] The components and parts by weight are as follows:

[0041] 100 parts by weight of the rubber masterbatch described in the second object of the present invention;

[0042] 1-5 parts by weight of a plasticizer;

[0043] 2-10 parts by weight of an activator;

[0044] 1-5 parts by weight of an antioxidant;

[0045] 0.5-3 parts by weight of sulfur;

[0046] 1-5 parts by weight of an accelerator.

[0047] The plasticizer may be any existing plasticizer used for preparing rubber materials. In the examples disclosed in the present invention, the plasticizer is paraffin wax.

[0048] The activator may be any existing activator used for preparing rubber materials. The activator may be one or more of zinc oxide, active zinc oxide, zinc carbonate, magnesium oxide, calcium oxide, lead monoxide, lead tetroxide, magnesium carbonate, basic lead carbonate, basic aluminum silicate, stannous chloride, cadmium oxide, calcium hydroxide, stearic acid, zinc stearate, lead stearate, oleic acid, lauric acid, zinc stearate, triethanolamine, diethylene glycol, poly-p-dinitrosobenzene, tetrachlorobenzoquinone, and trimethylolpropane trimethacrylate. In the examples disclosed in the present invention, based on 100 parts by weight of the raw rubber, the activator consists of 3 parts by weight of zinc oxide and 2 parts by weight of stearic acid.

[0049] The accelerator can be any existing accelerator used for preparing rubber materials. The accelerator can be one or more of dithiocarbamates, xanthates, thiurams, thiazoles, sulfenamides, guanidines, thioureas, aldehyde amines, and amine accelerators. In the disclosed embodiments of the present invention, based on 100 parts by weight of raw rubber, the accelerator is composed of 1.4 parts by weight of accelerator D (diphenylguanidine) and 1.4 parts by weight of accelerator NS (N-tert-butyl-2-benzothiazolesulfenamide).

[0050] The antioxidant can be any existing antioxidant used for preparing rubber materials. The antioxidant can be one or two or more of antioxidant 4010, antioxidant A, antioxidant D, antioxidant IPPD, antioxidant 6PPD, antioxidant 7PPD, antioxidant DTPD, antioxidant H, antioxidant DNP, antioxidant TPPD, antioxidant OPPD, antioxidant 4030, and antioxidant 8PPD. In the disclosed embodiments of the present invention, based on 100 parts by weight of raw rubber, the antioxidant is composed of 1 part by weight of antioxidant RD (2,2,4-trimethyl-1,2-dihydroquinoline polymer) and 2 parts by weight of 4010NA (N-cyclohexyl-N'-phenyl-p-phenylenediamine).

[0051] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0052] In the preparation method of the present invention, the modified silica slurry with the modifier well-dispersed is mixed with the rubber solution to form a uniform mixed slurry, and then the mixed slurry is dried by film laying to obtain a wet rubber masterbatch. Compared with the traditional dry mixing method, the preparation method of the present invention avoids problems such as dust generation, high energy consumption, and high cost during the dry mixing process. The overall process flow has low energy consumption, low cost, is green and environmentally friendly, and has high safety.

[0053] Compared with the existing wet mixing method, there is no need to add a flocculant, avoiding the damage of the flocculant to the uniform dispersion state of silica in the flocculation sedimentation method; there is no need to remove the solvent with steam, reducing the loss of the filler in the steam azeotrope.

[0054] By using Si69 and AEO-9 in combination and modifying silica simultaneously, the hydroxyl groups on the surface of silica are effectively reduced, making it change from hydrophilic to hydrophobic, thereby reducing the agglomeration of silica in rubber, increasing the compatibility between silica and rubber, and obtaining a wet rubber masterbatch with uniformly dispersed silica filler.

[0055] In the wet rubber masterbatch prepared by the present invention, the silica filler is uniformly dispersed in the rubber masterbatch, effectively improving the abrasion resistance and rolling resistance of the rubber masterbatch, and can be used for the preparation of rubber nanocomposites with excellent abrasion resistance and rolling resistance. The rubber masterbatch uses cis-butadiene rubber and natural rubber in combination to further improve the wear resistance and rolling resistance of the rubber masterbatch.

[0056] The rubber nanocomposite of the present invention is made from the above-mentioned silica-containing wet rubber masterbatch, and has excellent abrasion resistance and rolling resistance. It can be used for the cover rubber of conveyor belts, which is beneficial to enhancing the use effect of the rubber nanocomposite in the cover rubber of conveyor belts. Description of the Drawings

[0057] Figure 1 It is a transmission electron microscope image of the silica-containing wet rubber masterbatch prepared in Example 1;

[0058] Figure 2 It is a transmission electron microscope image of the silica-containing wet rubber masterbatch prepared in Example 2;

[0059] Figure 3 It is a transmission electron microscope image of the silica-containing wet rubber masterbatch prepared in Example 3;

[0060] Figure 4 It is a transmission electron microscope image of the silica-containing wet rubber masterbatch prepared in Example 4;

[0061] Figure 5 It is a transmission electron microscope image of the silica-containing wet rubber masterbatch prepared in Example 5;

[0062] Figure 6 It is a transmission electron microscope image of the silica-containing wet rubber masterbatch prepared in Example 6;

[0063] Figure 7 It is a transmission electron microscope image of the silica-containing wet rubber masterbatch prepared in Example 7;

[0064] Figure 8 It is a transmission electron microscope image of the silica-containing wet rubber masterbatch prepared in Example 8;

[0065] Figure 9 It is a transmission electron microscope image of the silica-containing wet rubber masterbatch prepared in Comparative Example 1;

[0066] Figure 10 It is a transmission electron microscope image of the silica-containing wet rubber masterbatch prepared in Comparative Example 2. Detailed Embodiments

[0067] The present invention will be specifically described below with reference to the specific drawings and embodiments. It is necessary to point out here that the following embodiments are only used for further illustration of the present invention and cannot be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art to the present invention based on the content of the present invention still fall within the protection scope of the present invention.

[0068] In the following embodiments and comparative examples, the sources of the main raw materials and main instruments used are as follows:

[0069] Silica: Rhodia Silica Co., Ltd., 1165;

[0070] Silane coupling agent Si69: Nanjing Nengde Chemical Co., Ltd., Si-69;

[0071] AEO-9: Shandong Yousuo Chemical Technology Co., Ltd., 03921400109;

[0072] Cyclohexane: Fuchen Chemical Co., Ltd.;

[0073] Butadiene rubber: BR9000;

[0074] Natural rubber: Linglong Tire Group, STR20;

[0075] Paraffin wax: Tianjin No. 1 Organic Chemical Plant;

[0076] Zinc oxide: Tianjin No. 1 Organic Chemical Plant;

[0077] Stearic acid: Tianjin No. 1 Organic Chemical Plant;

[0078] Antioxidant RD: Tianjin No. 1 Organic Chemical Plant;

[0079] Antioxidant 4010NA: Tianjin No. 1 Organic Chemical Plant;

[0080] Accelerator D: Tianjin No. 1 Organic Chemical Plant;

[0081] Accelerator NS: Tianjin No. 1 Organic Chemical Plant;

[0082] Sulfur: Shandong Tianshun Chemical Co., Ltd.;

[0083] Colloid mill: Shanghai Iken Machinery Co., Ltd., CM2000.

[0084] Example 1

[0085] A wet mixing preparation method of a silica-containing rubber masterbatch, the steps are as follows:

[0086] (1) By weight fraction, add silica and cyclohexane into container 1, add silane coupling agent Si69 and surfactant AEO-9 into container 2, pour the materials in container 1 into the colloid mill, grind for 30 minutes at 5 °C and 80 Hz, pour the materials in container 2 into the colloid mill, and continue to grind for 30 minutes at 5 °C and 80 Hz to obtain a modified silica slurry;

[0087] (2) Place the rubber in a cyclohexane solvent and perform mechanical stirring until the rubber is completely dissolved to obtain a rubber solution;

[0088] (3) Mix the modified silica slurry obtained in step (1) with the rubber solution obtained in step (2) under stirring at 2000 r / min for 30 minutes to obtain a masterbatch mixed slurry.

[0089] (4) Spread the masterbatch mixed slurry obtained in step (3) in portions to form a 3-mm film, and obtain a wet-mixed rubber masterbatch through air-blowing drying.

[0090] The transmission electron microscope (TEM) image of the prepared wet-mixed rubber masterbatch is as Figure 1 shown.

[0091] A preparation method of a rubber nanocomposite is as follows:

[0092] (5) Cut the wet-mixed rubber masterbatch obtained in step (4) into pieces and put them into an internal mixer at 150 °C for heat treatment for 5 minutes. After taking out the sheet and cooling, cut it and add it to the internal mixer. Then, add zinc oxide, stearic acid, paraffin wax, antioxidant RD, and antioxidant 4010NA to the internal mixer in sequence and mix for 2 minutes, and then take out. Transfer it to an open mill, add accelerator D, accelerator NS, and sulfur, and obtain a rubber mixture after mixing.

[0093] (6) Test the rubber mixture obtained in step (5) with a rotor rheometer to obtain its optimum cure time at 151 °C, and continue to prepare a rubber nanocomposite through flat vulcanization.

[0094] Among them, the dosage of each raw material is shown in Table 1. The transmission electron microscope (TEM) image of the prepared wet-mixed rubber masterbatch is as Figure 1 shown.

[0095] Example 2

[0096] The preparation method of the wet mixing of the silica-containing rubber masterbatch and the preparation method of the rubber nanocomposite in this example are the same as those in Example 1. Among them, the dosage of each raw material is shown in Table 1. The transmission electron microscope (TEM) image of the prepared wet-mixed rubber masterbatch is as Figure 2 shown.

[0097] Example 3

[0098] The preparation method of the wet mixing of the silica-containing rubber masterbatch and the preparation method of the rubber nanocomposite in this example are the same as those in Example 1. Among them, the dosage of each raw material is shown in Table 1. The transmission electron microscope (TEM) image of the prepared wet-mixed rubber masterbatch is as Figure 3 shown.

[0099] Example 4

[0100] The preparation method of the silica-containing rubber masterbatch by wet mixing and the preparation method of the rubber nanocomposite in this example are the same as those in Example 1. Among them, the dosages of each raw material are shown in Table 1. The transmission electron microscopy (TEM) image of the prepared wet-mixed rubber masterbatch is as Figure 4 shown.

[0101] Example 5

[0102] The preparation method of the silica-containing rubber masterbatch by wet mixing and the preparation method of the rubber nanocomposite in this example are the same as those in Example 1. Among them, the dosages of each raw material are shown in Table 1. The transmission electron microscopy (TEM) image of the prepared wet-mixed rubber masterbatch is as Figure 5 shown.

[0103] Example 6

[0104] The preparation method of the silica-containing rubber masterbatch by wet mixing and the preparation method of the rubber nanocomposite in this example are the same as those in Example 1 except that the film laying thickness is 5 mm.

[0105] Among them, the dosages of each raw material are shown in Table 1. The transmission electron microscopy (TEM) image of the prepared wet-mixed rubber masterbatch is as Figure 6 shown.

[0106] Example 7

[0107] The preparation method of the silica-containing rubber masterbatch by wet mixing and the preparation method of the rubber nanocomposite in this example are the same as those in Example 1 except that the film laying thickness is 10 mm.

[0108] Among them, the dosages of each raw material are shown in Table 1.

[0109] The transmission electron microscopy (TEM) image of the prepared wet-mixed rubber masterbatch is as Figure 7 shown.

[0110] Example 8

[0111] The preparation method of the silica-containing rubber masterbatch by wet mixing and the preparation method of the rubber nanocomposite in this example are the same as those in Example 1 except that the grinding temperature when preparing the modified silica slurry is 30 °C.

[0112] Among them, the dosages of each raw material are shown in Table 1.

[0113] The transmission electron microscopy (TEM) image of the prepared wet-mixed rubber masterbatch is as Figure 8 shown.

[0114] Comparative Example 1

[0115] The preparation method of the silica-containing rubber masterbatch by wet mixing and the preparation method of the rubber nanocomposite in this example are the same as those in Example 1, except that "the addition method of the silane coupling agent Si69 and the surface modifier AEO-9 is separate addition, and the time interval between the two additions is 30 min (that is, first add the silane coupling agent Si69 and grind for 30 min, then add the surface modifier AEO-9 and grind for 30 min)".

[0116] Among them, the dosages of each raw material are shown in Table 2.

[0117] The transmission electron microscope (TEM) image of the prepared wet-mixed rubber masterbatch is as Figure 9 shown.

[0118] Comparative Example 2

[0119] The preparation method of the silica-containing rubber masterbatch by wet mixing and the preparation method of the rubber nanocomposite in this example are the same as those in Example 1, except that "the method for removing the solvent from the masterbatch mixed slurry is azeotropic distillation with water vapor".

[0120] Among them, the dosages of each raw material are shown in Table 2.

[0121] The transmission electron microscope (TEM) image of the prepared wet-mixed rubber masterbatch is as Figure 10 shown.

[0122] Comparative Example 3

[0123] The preparation method of the silica-containing rubber masterbatch by wet mixing and the preparation method of the rubber nanocomposite in this example are the same as those in Example 1, except that "the stirring speed when mixing the silica slurry and the rubber solution is 500 r / min".

[0124] Among them, the dosages of each raw material are shown in Table 2.

[0125] Comparative Example 4

[0126] The preparation method of the silica-containing rubber masterbatch by wet mixing and the preparation method of the rubber nanocomposite in this example are the same as those in Example 1. Among them, the dosages of each raw material are shown in Table 2.

[0127] Comparative Example 5

[0128] The preparation method of the silica-containing rubber masterbatch by wet mixing and the preparation method of the rubber nanocomposite in this example are the same as those in Example 1. Among them, the dosages of each raw material are shown in Table 2.

[0129] Table 1

[0130]

[0131] Table 2

[0132]

[0133]

[0134] I. Morphology of Materials

[0135] Transmission electron microscope (TEM) images of the rubber masterbatches prepared in Examples 1-8 and Comparative Examples 1-2 are as Figures 1-10 shown. From the TEM images, the silica and rubber can be observed. Figure 9 、 10 The TEM images of show that the silica in the rubber masterbatches prepared by the wet method in Comparative Examples 1 and 2 is unevenly distributed in the colloidal material, and there is local agglomeration of silica. Figures 1-8 The TEM image of shows that the silica in the rubber masterbatch prepared by the wet method of the present invention has a good distribution state in the colloidal material and is evenly distributed in the colloidal material. It can be concluded that, compared with the wet methods of Comparative Examples 1 and 2, the silica in the rubber masterbatch prepared by the wet method of the present invention has better dispersibility in the colloidal material, and the wet method of the present invention improves the dispersion performance of silica in the colloidal material.

[0136] II. Performance Tests

[0137] The test items include minimum torque (ML, unit: dMm), maximum torque (MH, unit: dMm), scorch time (T10, unit: min), processing optimum cure time (T90, unit: min), Mooney viscosity (ML(1+4)100°C, unit: °), hardness of vulcanizate (unit: Shore A), tensile strength (unit: MPa), elongation at break (%), 100% modulus (unit: MPa), 300% modulus (unit: MPa), tear strength (unit: kN / m), DIN abrasion value (unit: mm3), rolling resistance factor (RRF, unit: MPa), and difference in storage modulus ΔG' (MPa).

[0138] Among them, the test standards for vulcanization characteristics such as ML, MH, T10, T90, and ML(1+4)100°C refer to GB / T9869-2014, the hardness test standard refers to GB / T531.1-2008, the test standards for tensile strength, elongation at break, 100% modulus, and 300% modulus refer to GB / T528-2009, the tear strength test standard refers to GB / T 529-2008, and the DIN abrasion performance test standard refers to GB / T9867-2008. The storage modulus G' is measured by a rubber processing analyzer RPA, and ΔG' is obtained by taking the difference of the storage modulus G'. The dynamic thermomechanical analyzer DMA is used to measure E' and E", and then according to the formula RRF = E" / E' 4 / 3The RRF was calculated. In the RPA test, the test conditions for the rubber compound were as follows: the test temperature was 60 °C, the scanning frequency was 1 Hz, and the strain scanning test range was a strain amplitude range of 0 to 200%; the test conditions for the vulcanizate were: the test temperature was 60 °C, the scanning frequency was 10 Hz, and the strain scanning test range was a strain amplitude range of 0 to 42%. The DMA test used a temperature scanning mode, with a temperature range of -20 to 100 °C, a pre-strain of 5%, a dynamic strain of 2%, 10 HZ, and 3 °C / min.

[0139] The test results are shown in Tables 3 and 4.

[0140] Table 3

[0141]

[0142] Table 4

[0143]

[0144]

[0145] From the data in Tables 3 and 4, it can be concluded that: compared with the rubber masterbatch prepared in Comparative Example 4, the Mooney viscosity and Shore hardness of the rubber masterbatch prepared in Example 1 decreased, while the tensile strength, elongation at break, 100% modulus, 300% modulus tear strength, DIN abrasion value, and rolling resistance factor increased; compared with the rubber masterbatch prepared in Comparative Example 5, the Mooney viscosity and Shore hardness of the rubber masterbatch prepared in Example 1 increased, while the tensile strength, elongation at break, 100% modulus, 300% modulus tear strength, DIN abrasion value, and rolling resistance factor decreased; this shows that using cis-butadiene rubber and natural rubber in a specific weight ratio can improve the disadvantages of poor mechanical properties of styrene-butadiene rubber and poor abrasion and rolling resistance properties of natural rubber, and a rubber masterbatch with good mechanical properties, rolling resistance properties, and wear resistance can be prepared by combining natural rubber and cis-butadiene rubber.

[0146] From the data in Table 3, it can be concluded that: compared with the rubber masterbatches prepared in Examples 1, 3, 4, and 5, the rubber masterbatch prepared in Example 2 has better mechanical properties, abrasion properties, and rolling resistance properties. This shows that the modification effect of AEO-9 and Si699 compounded and used in a specific weight ratio (about 1:3) on silica is better, and the properties of the prepared rubber masterbatch are also improved.

[0147] From the data in Table 3, it can be concluded that: compared with the rubber masterbatches prepared in Examples 6 and 7, the rubber masterbatch prepared in Example 2 has better mechanical properties, abrasion properties, and rolling resistance properties. This shows that during the film laying and drying process of the masterbatch mixed slurry, if the film laying thickness is too thick, it will instead cause the performance of the rubber masterbatch to deteriorate, and when the film thickness is about 3 mm, its performance is the best.

[0148] It can be concluded from the data in Table 3 that compared with the rubber masterbatch prepared in Example 8, the rubber masterbatch prepared in Example 2 has better mechanical properties, abrasion resistance and rolling resistance. This shows that too high grinding temperature of the colloid mill during the modification of silica will lead to deterioration of the properties of the rubber masterbatch, and the modification effect is better when the modification temperature is selected around 5°C.

[0149] It can be concluded from the data in Tables 3 and 4 that compared with the rubber masterbatch prepared in Comparative Example 2 (azeotropic method with water vapor), the rubber masterbatch prepared in Example 2 has better mechanical properties, abrasion resistance and rolling resistance. This shows that the effect of drying the mother rubber mixed slurry by film laying and air blowing is better, and the properties of the prepared rubber masterbatch phase are better.

[0150] It can be concluded from the data in Tables 3 and 4 that compared with the rubber masterbatch prepared in Comparative Example 3 (stirring speed of 500 r / min), the rubber masterbatch prepared in Example 2 has better mechanical properties, abrasion resistance and rolling resistance. This shows that low-speed stirring during the mixing of the silica slurry and the rubber solution results in poor filler reinforcement effect, and the properties of the prepared rubber masterbatch deteriorate.

Claims

1. A preparation method of rubber masterbatch, characterized in that, the preparation method includes the following steps: Step 1: Add silica and a dispersion medium into a grinding device for grinding, and then add a silane coupling agent and fatty alcohol polyoxyethylene ether and continue grinding to obtain a modified silica slurry; Step 2: Mix rubber with a solvent and dissolve to obtain a rubber solution; Step 3: Mix the modified silica slurry and the rubber solution under stirring conditions to obtain a masterbatch mixed slurry; Step 4: Spread and dry the masterbatch mixed slurry to obtain the rubber masterbatch.

2. The preparation method according to claim 1, characterized in that, in Step 1, the grinding temperature is 5-30°C, preferably 5-10°C.

3. The preparation method according to claim 1, characterized in that, in Step 3, the stirring speed is 1000-3000 r / min, preferably 1000-2000 r / min.

4. The preparation method according to claim 1, characterized in that, in Step 4, the spreading film thickness is 1-10 mm, preferably 3-5 mm.

5. The preparation method according to claim 1, characterized in that, the weight ratio of the silane coupling agent to the fatty alcohol polyoxyethylene ether is 9:1-15, preferably 9:3-12.

6. A rubber masterbatch, characterized in that, the rubber masterbatch is prepared by using the preparation method described in any one of claims 1-5.

7. The rubber masterbatch according to claim 6, characterized in that, the rubber masterbatch is prepared from raw materials including the following components; the components and parts by weight are as follows: 100 parts by weight of rubber; 1000-2000 parts by weight of solvent, preferably 1250-1667 parts by weight; 30-150 parts by weight of silica, preferably 40-50 parts by weight; 300-3000 parts by weight of dispersion medium, preferably 500-650 parts by weight; 0.1-10 parts by weight of silane coupling agent, preferably 4-6 parts by weight; 0.1-10 parts by weight of fatty alcohol polyoxyethylene ether, preferably 2-6 parts by weight; the rubber is composed of cis-butadiene rubber and natural rubber; based on 100 parts by weight of the total rubber weight, the cis-butadiene rubber is 70-100 parts by weight, and the natural rubber is 30-0 parts by weight; preferably, the cis-butadiene rubber is 80-90 parts by weight, and the natural rubber is 20-10 parts by weight.

8. The rubber masterbatch according to claim 7, characterized in that, the solvent is cyclohexane; or / and, the dispersion medium is cyclohexane; or / and, the silane coupling agent is selected from one or more of bis(γ-triethoxysilylpropyl)tetrasulfide, bis(3-triethoxysilylpropyl)disulfide, γ-mercaptopropyltriethoxysilane, and γ-mercaptopropyltrimethoxysilane; or / and, the fatty alcohol polyoxyethylene ether is selected from one or more of AEO-3, AEO-5, AEO-7, AEO-9, and AEO-11.

9. A rubber nanocomposite, characterized in that, the rubber nanocomposite is prepared by using the rubber masterbatch described in any one of claims 6-8 as the masterbatch for mixing.

10. The rubber nanocomposite according to claim 9, characterized in that, the raw materials for preparing the rubber nanocomposite further include the following components in parts by weight; based on 100 parts by weight of the rubber masterbatch: 1-5 parts by weight of plasticizer; 2-10 parts by weight of activator; 1-5 parts by weight of antioxidant; 0.5-3 parts by weight of sulfur; 1-5 parts by weight of accelerator.

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