Natural rubber / white carbon black masterbatch taking beta-type sepiolite as suspension stabilizer

Abstract

The invention discloses a natural rubber / white carbon black masterbatch taking beta-type sepiolite as a suspension stabilizer, and relates to a wet-process mixed rubber material. The preparation method comprises the following steps: firstly, carrying out high-speed stirring or ultrasonic mixing on unmodified or modified beta-type sepiolite serving as a suspension stabilizer and white carbon black aqueous slurry to prepare stable white carbon black slurry, then adding natural latex into the white carbon black slurry, and carrying out stirring, flocculation, dehydration and drying to obtain the natural rubber / white carbon black wet-process masterbatch. The method can be used for mixing white carbon black with high filling amount and high specific surface area with natural rubber, and the process is low in energy consumption and free of dust pollution; according to the method, the use of organic modification additives such as a surfactant is avoided, meanwhile, the loss amount of the white carbon black is small in the process, and the interface bonding effect between the white carbon black and the natural rubber is enhanced. The white carbon black in the master batch is uniformly distributed, and the tensile strength, stress at definite elongation, tear strength, dynamic mechanical properties and the like are obviously improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wet-mixed rubber materials, and particularly to a natural rubber / silica masterbatch with β-type sepiolite as a suspension stabilizer. Background Art

[0002] Among many basic raw materials for rubber, natural rubber is a widely used, sustainable and renewable material, which is prepared by processing the aqueous natural latex produced by the Hevea brasiliensis tree through methods such as flocculation and drying. However, due to the disadvantages of low modulus, poor abrasion resistance and durability of single natural rubber, it is usually necessary to add reinforcing fillers to endow it with high strength modulus, wear resistance and weather resistance and other excellent properties to meet the usage requirements in various application scenarios. Among them, silica, as a commonly used rubber reinforcing material, can not only improve the physical and mechanical properties of natural rubber composites, but also endow the rubber material with low rolling resistance and excellent wet skid resistance, and is an excellent material for preparing "green tires". In recent years, with the in-depth promotion of the concept of "green tires", the demand for high-performance natural rubber / silica composites has been increasing, and the consumption of silica has also been increasing. However, there are a large number of silanol groups on the surface of silica, which are hydrophilic and prone to self-aggregation, making it difficult to mix into the natural rubber matrix during the traditional dry mixing process, with poor dispersibility, often requiring multi-stage and long-time mixing, high energy consumption and dust pollution during the process; at the same time, under the long-term shearing action of natural rubber, the macromolecular chains of natural rubber are severely damaged, resulting in a decline in the dynamic and static mechanical properties of the composite material.

[0003] For natural rubber in its native state as an aqueous latex and silica with certain hydrophilicity, preparing natural rubber / silica composites by wet mixing is considered a production method that combines energy conservation, environmental protection, and the preparation of rubber composites with excellent physical properties. In the existing process of wet-preparing natural rubber / silica masterbatch, affected by the easy self-aggregation of silica particles, the prepared aqueous silica suspension is extremely prone to self-aggregation and sedimentation. During wet mixing, it is difficult to mix evenly with natural latex particles, resulting in partial loss of silica. This loss increases continuously with the increase in the amount of silica used, thus affecting the performance of the wet masterbatch. To address the above problems, previous studies mostly used high-speed grinding and surface-treated silica with an amphiphilic surfactant to prepare an aqueous silica suspension, and at the same time supplemented it with long-term mechanical stirring to ensure the uniformity and stability of the aqueous silica suspension for better use in the wet mixing of natural latex. Although such methods can obtain natural rubber / silica composites with uniformly dispersed silica, affected by the surfactant, the silane coupling effect between natural rubber and silica becomes weaker, reducing the interfacial bonding ability between rubber and filler; at the same time, the introduction of organic surfactants will also increase the treatment steps and costs of flocculation waste liquid; in addition, the process steps of high-speed grinding and long-term stirring are complex and energy consumption is high. Therefore, exploring a simple and efficient method for preparing aqueous suspensions to solve the interfacial bonding between natural rubber and silica and the problem of silica loss in the wet mixing process is a very meaningful task.

[0004] Sepiolite is a natural magnesium-rich hydrated silicate clay mineral with a special one-dimensional fibrous crystal morphology. Its crystal lattice is generally considered to be composed of Si-O tetrahedral sheets and Mg-O octahedral sheets, and at the same time has a 2:1 type banded structure parallel to the C axis. And the discontinuous octahedral sheets are connected to the reverse tetrahedral sheets through oxygen atoms to form alternating bonds. This alternating connection method enables sepiolite to form a large number of channel and tunnel pore structures and a rich surface of silanol groups (Si-OH), making it have excellent adsorption, reinforcement, and aqueous suspension stability. Sepiolite is mainly divided into two types: α-type (hydrothermal type) and β-type (sedimentary rock type). The sepiolite in China is mainly of the β-type, with relatively low crystal development and high associated mineral content. It is mainly distributed in places such as Xiangtan, Hunan, and its reserves account for about one-third of the world's reserves, but the development and utilization rate is relatively low, mainly developing low-value-added adsorption products and exporting ore raw materials.

[0005] In an aqueous phase system, sepiolite can not only stably suspend alone, but also stabilize the suspension state of other types of inorganic fillers without adding surfactants. Without adding suspension aids such as surfactants and surface activation treatment, sepiolite can stably disperse anisotropic inorganic fillers such as carbon nanotubes and graphene in the aqueous phase system under ultrasonic action, and then prepare uniform and stable buckypaper or conductive film materials that are both rigid and flexible. Using β-type sepiolite as an inorganic suspension stabilizer, a stable aqueous suspension of silica is first prepared. After mixing with natural latex, it is flocculated, dehydrated and dried to obtain a high-performance natural rubber / silica masterbatch.

[0006] The present invention aims to solve the problems of effective interfacial bonding between natural rubber and silica and reducing the loss of silica in the wet mixing process. Specifically, by using β-type sepiolite as an inorganic suspension stabilizer, without adding surfactants or undergoing complex surface activation treatment, the dispersion of silica in the aqueous suspension is effectively stabilized. In this way, silica can be more evenly combined with natural rubber during mixing, while reducing the loss of silica during the preparation process, and reducing energy consumption and environmental pollution, thereby preparing a high-performance natural rubber / silica composite material with excellent physical and mechanical properties. This method takes into account environmental protection and efficiency, meeting the current industrial requirements for high-performance sustainable materials. Summary of the Invention

[0007] In order to achieve the above invention purpose and address the above technical problems,

[0008] The present invention provides a natural rubber / silica masterbatch with β-type sepiolite as a suspension stabilizer, and the masterbatch is prepared by the following steps:

[0009] Preparation of A1 aqueous suspension of silica: Select unmodified or modified β-type sepiolite as a suspension stabilizer, mix it with silica and water, and prepare a uniform and stable aqueous suspension of silica under high-speed stirring or ultrasonic dispersion.

[0010] A2 Wet mixing: Add natural latex to the aqueous suspension of silica obtained in A1, and stir to obtain a mixed slurry of natural latex and aqueous suspension of silica.

[0011] A3 Flocculation, dehydration, and drying:

[0012] B1 Slowly add a flocculant to the mixed slurry in A2, stir and mix evenly, and let it stand for flocculation.

[0013] B2 Extrude and dehydrate the flocculated masterbatch in B1 through a kneader and rinse it. The obtained flocculation liquid can be recycled and reused.

[0014] B3 After crushing the extruded masterbatch in B2 through a cracker, dry it to obtain a natural rubber / silica masterbatch.

[0015] Preferably, the unmodified β-sepiolite in step A1 is β-sepiolite powder or suspension; the modified β-sepiolite is one or a mixture of several of β-sepiolite powder or suspension modified with silane coupling agent, β-sepiolite powder or suspension modified with quaternary ammonium salt.

[0016] Preferably, the silicon dioxide content of the precipitated silica in step A1 is 95% - 100%, and the nitrogen adsorption specific surface area (BET) is 100 m2 / g - 300 m2 / g.

[0017] Preferably, the speed of high-speed stirring in A1 is 1000 rpm - 20000 rpm; the energy required for ultrasonic dispersion per gram of precipitated silica suspension is 0.1 - 5 J / g.

[0018] Preferably, the β-sepiolite in A1 accounts for 0.2% - 2.0% of the total mass of the suspension, and the mass of precipitated silica accounts for 10% - 30% of the total mass of the suspension.

[0019] Preferably, the natural latex in A2 is a mixed solution of one or several of field natural latex, concentrated natural latex, and epoxidized natural latex with a solid content of 20% - 50%.

[0020] Preferably, based on 100 parts by mass of the dry rubber in the natural latex in A2, the total added mass of precipitated silica and β-sepiolite suspension stabilizer in the precipitated silica aqueous suspension is 10 parts - 120 parts.

[0021] Preferably, the stirring speed in A2 is 10 - 500 rpm, and the stirring time is 10 - 60 min.

[0022] Preferably, the flocculant added in A3 is one or several of formic acid, calcium chloride, methanol, and protease.

[0023] Preferably, the addition amount of the flocculant in B1 is 0 - 1.0% of the dry weight of the natural latex.

[0024] The mechanism of the present invention lies in:

[0025] As a one-dimensional fibrous rod-shaped structural material with special pore properties and surface activity, when the solid content of sepiolite of type β in the aqueous dispersion solution is greater than its rheological percolation threshold, the amount of sepiolite fibers is sufficient. With the assistance of weak chemical action, the dispersed rod-shaped fibers physically overlap with each other to form a stable three-dimensional network structure. After adding silica, the particles are restricted in the three-dimensional network constructed by sepiolite fibers and it is difficult to form sufficiently large sedimentable aggregated particles. That is, the "space-confined" sepiolite network structure enables the silica slurry to be stably suspended. After adding natural latex, the contact amount with silica increases. During demulsification, under the adsorption of sepiolite and silica, the rubber molecular chains can be more evenly wrapped, adsorbed or entangled between the filler particles to form a uniform and stable composite masterbatch. At the same time, less filler is lost, and a rubber composite material with uniformly dispersed silica is prepared. In addition, a large number of active groups are contained on the surface of sepiolite and it has an anisotropic fibrous rod shape, which can generate a strong interfacial bonding effect with natural rubber and produce a synergistic reinforcement effect when compounded with silica, and thus a natural rubber / silica masterbatch with excellent dynamic and static mechanical properties is obtained.

[0026] The beneficial effects brought by the technical solution provided in the embodiments of the present invention are as follows:

[0027] 1) In the present invention, inorganic sepiolite of type β is used as the stabilizer of the silica aqueous suspension, and the obtained silica suspension can remain stable without long-term stirring, reducing energy consumption;

[0028] 2) Using sepiolite of type β as the suspension stabilizer, there is no organic matter residue in the waste liquid after wet mixing, and the application treatment is simple;

[0029] 3) In the natural rubber / silica masterbatch prepared by applying this method, the silica is uniformly dispersed in the rubber matrix, and under the synergistic reinforcement of sepiolite, the dynamic and static mechanical properties of the obtained masterbatch are significantly improved;

[0030] 4) When applying this method to prepare the natural rubber / silica masterbatch, the production process and equipment of standard natural rubber can be directly applied, the process is simple, there is no dust pollution during the production process, and the energy consumption cost is low. Description of the Drawings

[0031] Figure 1 It is a flowchart of the embodiments of the present invention. Detailed Embodiments

[0032] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments. Of course, the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] In the examples, the field latex and concentrated natural latex were provided by the Rubber Research Institute of Chinese Academy of Tropical Agricultural Sciences, and the rest of the materials were commercially available.

[0034] Example 1

[0035] Based on 100 parts by weight (phr) of the dry rubber of natural latex, 46 phr of silica with a specific surface area of 175 m 2 / g, the silica content of the silica is 98%, and the powder was added to 288 phr of an aqueous solution containing 4 phr of β-sepiolite to prepare a silica suspension with a mass percentage content of 15%. Stir for 15 min at a rotation speed of 8000 rpm. Take 333.3 phr of concentrated natural latex diluted to a solid content of 30% and add it to the above silica suspension. Stir at a rotation speed of 200 rpm for 20 min, then add formic acid and stir for flocculation. After dehydration, washing, crushing and drying, a natural rubber / silica masterbatch containing 100 phr of rubber and 50 phr of filler was obtained. The above masterbatch was mixed with 4 phr of silane coupling agent (Si 69), 5 phr of zinc oxide, 2 phr of stearic acid, 2 phr of antioxidant 4020, 2 phr of accelerator CBS, 1 phr of accelerator DM and 2 phr of sulfur by a kneader and an open mill to obtain a natural rubber / silica blend. After standing for 12 h, the vulcanization curve was measured and vulcanized at 150 °C, and the dynamic and static mechanical properties were tested. The results are shown in Table 1.

[0036] Example 2

[0037] Based on 100 parts by weight (phr) of the dry rubber of natural latex, 47 phr of silica powder with a specific surface area of 175 m2 / g was added to 287 phr of an aqueous solution containing 3 phr of β-sepiolite to prepare a silica suspension with a mass percentage content of 15%. Stir for 15 min at a rotation speed of 8000 rpm. Take 333.3 phr of concentrated natural latex diluted to a solid content of 30% and add it to the above silica suspension. Stir at a rotation speed of 200 rpm for 20 min, then add formic acid and stir for flocculation. After dehydration, washing, crushing and drying, a natural rubber / silica masterbatch containing 100 phr of rubber and 50 phr of filler was obtained. The remaining steps were the same as in Example 1.

[0038] Example 3

[0039] Based on 100 parts per hundred rubber (phr) of the dry natural rubber latex, 45 phr of precipitated silica powder with a specific surface area of 175 m2 / g was added to 289 phr of an aqueous solution containing 5 phr of β-sepiolite to prepare a precipitated silica suspension with a mass percentage of 15%. Stir for 15 min at a rotation speed of 8000 rpm. Take 333.3 phr of concentrated natural rubber latex diluted to a solid content of 30% and add it to the above-mentioned precipitated silica suspension. Stir at a rotation speed of 200 rpm for 20 min, then add formic acid and stir for flocculation. After dehydration, rinsing, crushing, and drying, a natural rubber / precipitated silica masterbatch containing 100 phr of rubber and 50 phr of filler was obtained. The remaining steps were the same as in Example 1.

[0040] Example 4

[0041] Based on 100 parts per hundred rubber (phr) of the dry natural rubber latex, 47 phr of precipitated silica powder with a specific surface area of 200 m2 / g was added to 287 phr of an aqueous solution containing 3 phr of β-sepiolite to prepare a precipitated silica suspension with a mass percentage of 15%. Stir for 15 min at a rotation speed of 8000 rpm. Take 400 phr of fresh field natural rubber latex diluted to a solid content of 25% and add it to the above-mentioned precipitated silica suspension. Stir at a rotation speed of 200 rpm for 15 min, then add formic acid and stir for flocculation. After dehydration, rinsing, crushing, and drying, a natural rubber / precipitated silica masterbatch containing 100 phr of rubber and 50 phr of filler was obtained. The remaining steps were the same as in Example 1.

[0042] Example 5

[0043] Based on 100 parts per hundred rubber (phr) of the dry natural rubber latex, 46 phr of precipitated silica powder with a specific surface area of 200 m2 / g was added to 288 phr of an aqueous solution containing 4 phr of β-sepiolite to prepare a precipitated silica suspension with a mass percentage of 15%. Stir for 15 min at a rotation speed of 8000 rpm. Take 400 phr of fresh field natural rubber latex diluted to a solid content of 25% and add it to the above-mentioned precipitated silica suspension. Stir at a rotation speed of 200 rpm for 15 min, then add formic acid and stir for flocculation. After dehydration, rinsing, crushing, and drying, a natural rubber / precipitated silica masterbatch containing 100 phr of rubber and 50 phr of filler was obtained. The remaining steps were the same as in Example 1.

[0044] Example 6

[0045] Based on 100 parts by weight (phr) of the dry natural rubber latex, 45 phr of silica powder with a specific surface area of 200 m2 / g was added to 289 phr of an aqueous solution containing 5 phr of β-type sepiolite to prepare a silica suspension with a mass percentage content of 15%. Stir for 15 min at a speed of 8000 rpm. Take 400 phr of fresh field natural rubber latex diluted to a solid content of 25% and add it to the above silica suspension. Stir for 15 min at a speed of 200 rpm, then add formic acid and stir for flocculation. After dehydration, washing, crushing, and drying, a natural rubber / silica masterbatch containing 100 phr of rubber and 50 phr of filler is obtained. The remaining steps are the same as in Example 1.

[0046] Example 7

[0047] Based on 100 parts by weight (phr) of the dry natural rubber latex, 18 phr of silica powder with a specific surface area of 175 m2 / g was added to 182 phr of an aqueous solution containing 2 phr of β-type sepiolite to prepare a silica suspension with a mass percentage content of 10%. Stir for 15 min at a speed of 8000 rpm. Take 250 phr of concentrated natural rubber latex diluted to a solid content of 40% and add it to the above silica suspension. Stir for 20 min at a speed of 200 rpm, then add formic acid and stir for flocculation. After dehydration, washing, crushing, and drying, a natural rubber / silica masterbatch containing 100 phr of rubber and 20 phr of filler is obtained. The remaining steps are the same as in Example 1.

[0048] Example 8

[0049] Based on 100 parts by weight (phr) of the dry natural rubber latex, 27 phr of silica powder with a specific surface area of 175 m2 / g was added to 273 phr of an aqueous solution containing 3 phr of β-type sepiolite to prepare a silica suspension with a mass percentage content of 10%. Stir for 15 min at a speed of 8000 rpm. Take 250 phr of concentrated natural rubber latex diluted to a solid content of 40% and add it to the above silica suspension. Stir for 20 min at a speed of 200 rpm, then add formic acid and stir for flocculation. After dehydration, washing, crushing, and drying, a natural rubber / silica masterbatch containing 100 phr of rubber and 30 phr of filler is obtained. The remaining steps are the same as in Example 1.

[0050] Example 9

[0051] Based on 100 parts per hundred rubber (phr) of the dry natural rubber latex, 55 phr of white carbon black powder with a specific surface area of 175 m2 / g was added to 345 phr of an aqueous solution containing 5 phr of β-type sepiolite to prepare a white carbon black suspension with a mass percentage content of 15%. Stir for 15 min at a rotation speed of 8000 rpm. Take 333.3 phr of concentrated natural rubber latex diluted to a solid content of 30% and add it to the above white carbon black suspension. Stir for 20 min at a rotation speed of 200 rpm, then add formic acid and stir for flocculation. After dehydration, rinsing, crushing, and drying, a natural rubber / white carbon black masterbatch containing 100 phr of rubber and 60 phr of filler was obtained. The remaining steps are the same as in Example 1.

[0052] Comparative Example 1

[0053] Take 166.7 phr of concentrated natural rubber latex, add formic acid and stir for flocculation. After dehydration, crushing, and drying, 100 phr of natural rubber was obtained. Mix it with 50 phr of white carbon black powder with a specific surface area of 175 m2 / g, 4 phr of silane coupling agent (Si 69), 5 phr of zinc oxide, 2 phr of stearic acid, 2 phr of antioxidant 4020, 2 phr of accelerator CBS, 1 phr of accelerator DM, and 2 phr of sulfur through a kneader and an open mill to obtain a natural rubber / white carbon black blend. After standing for 12 h, measure the vulcanization curve and vulcanize at 150 °C, and test the dynamic and static mechanical properties. The results are shown in Table 1.

[0054] Comparative Example 2

[0055] Based on 100 parts per hundred rubber (phr) of the dry natural rubber latex, 50 phr of white carbon black powder with a specific surface area of 175 m2 / g was added to 284 phr of an aqueous solution to prepare a white carbon black suspension with a mass percentage content of 15%. Stir for 15 min at a rotation speed of 8000 rpm. Take 333.3 phr of concentrated natural rubber latex diluted to a solid content of 30% and add it to the above white carbon black suspension. Stir for 20 min at a rotation speed of 200 rpm, then add formic acid and stir for flocculation. After dehydration, rinsing, crushing, and drying, a natural rubber / white carbon black masterbatch containing 100 phr of rubber and 50 phr of filler was obtained. The remaining steps are the same as in Example 1.

[0056] Comparative Example 3

[0057] Based on 100 parts per hundred (phr) of the dry rubber mass of natural latex, 50 phr of silica powder with a specific surface area of 175 m2 / g and 1.5 phr of sodium dodecylbenzenesulfonate were added to 284 phr of an aqueous solution. After grinding in a ball mill for 2 h, a silica suspension with a mass percentage of 15% was obtained. 333.3 phr of concentrated natural latex diluted to a solid content of 30% was added to the above silica suspension, stirred at a speed of 200 rpm for 20 min, and then formic acid was added and stirred for flocculation. After dehydration, rinsing, crushing, and drying, a natural rubber / silica masterbatch containing 100 phr of rubber and 50 phr of filler was obtained. The remaining steps were the same as in Example 1.

[0058] Experimental tests:

[0059] 1. Tensile strength, modulus at a specified elongation, and elongation at break were tested according to Standard GB / T 528-2009;

[0060] 2. Tear strength was tested according to Standard GB / T 529-2008;

[0061] 3. DIN abrasion was tested according to Standard GB / T 9867-2008;

[0062] 4. For the dynamic mechanical property test, a temperature sweep was performed on the vulcanized rubber composite sample using a dynamic mechanical analyzer. The temperature range was -80 °C to +80 °C, the heating rate was 3 °C / min, the strain was 0.1%, and the frequency was 10 Hz;

[0063] 5. The filler loss rate was the percentage of the solid content after drying the remaining liquid after flocculation in wet mixing to the total amount of theoretical natural rubber and silica.

[0064] Table 1 Comparative data of the mechanical properties of the rubber compounds in the comparative examples and examples

[0065]

[0066]

[0067] As can be seen from Table 1, when the raw latex and silica have the same quality, during the wet preparation of natural rubber / silica masterbatch with β-type sepiolite as the suspension stabilizer, the loss rate of the filler is significantly lower than that of the existing wet mixing technology; at the same time, the dynamic and static mechanical properties of the obtained masterbatch, such as modulus at a specified elongation, tensile strength, tear strength, abrasion resistance, wet skid resistance, and rolling resistance, are better than those of the composites obtained by the existing wet mixing and traditional dry mixing. The method of wet mixing natural rubber / silica masterbatch with β-type sepiolite as the suspension stabilizer also has obvious process and performance advantages for fresh field natural latex and silica materials with a higher specific surface area.

[0068] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A natural rubber / white carbon black masterbatch with β-sepiolite as a suspension stabilizer, characterized in that: The masterbatch is made by the following steps: A1 Preparation of silica aqueous suspension: unmodified or modified β-sepiolite is selected as a suspension stabilizer, mixed with silica and water, and a uniform and stable silica aqueous suspension is prepared under high-speed stirring or ultrasonic dispersion; A2 wet mixing: adding natural rubber latex to the silica aqueous suspension obtained in A1, stirring to obtain a mixed slurry of natural rubber latex and silica aqueous suspension; A3 flocculation, dehydration and drying: B1 slowly adds flocculant to the mixed slurry of A2, stirs and mixes evenly, and allows to stand for flocculation; B2: The masterbatch after flocculation in B1 is squeezed, dehydrated and washed by a kneader, and the obtained flocculation liquid can be recycled and reused; B3: The masterbatch extruded in B2 is crushed by a rubber crusher and then dried to obtain a natural rubber / white carbon black masterbatch.

2. The natural rubber / white carbon black masterbatch according to claim 1, characterized in that: In step A1, the unmodified β-type sepiolite is β-type sepiolite powder or suspension; the modified β-type sepiolite is β-type sepiolite powder or suspension modified by silane coupling agent, β-type sepiolite powder or suspension modified by quaternary ammonium salt, or a mixture of several thereof.

3. The natural rubber / white carbon black masterbatch according to claim 1, characterized in that: The silica content of the white carbon black in step A1 is 95% to 100%, and the nitrogen adsorption specific surface area (BET) is 100 m 2 / g-300m 2 / g.

4. The natural rubber / white carbon black masterbatch according to claim 1, characterized in that: The speed of the high-speed stirring in A1 is 1000rpm-20000rpm; the energy required for ultrasonic dispersion of each gram of white carbon black suspension is 0.1-5J / g.

5. The natural rubber / white carbon black masterbatch according to claim 1, characterized in that: In the A1, the beta-type sepiolite accounts for 0.2% to 2.0% of the total mass of the suspension, and the mass of white carbon black accounts for 10% to 30% of the total mass of the suspension.

6. The natural rubber / white carbon black masterbatch according to claim 1, characterized in that: The natural latex in A2 is a mixture of one or more of field natural latex, concentrated natural latex, and epoxidized natural latex with a solid content of 20% to 50%.

7. The natural rubber / white carbon black masterbatch according to claim 1, characterized in that: The total mass of the added silica and β-type sepiolite suspension stabilizer in the silica aqueous phase suspension is 10 to 120 parts based on 100 parts of dry rubber in the natural rubber latex in A2.

8. The natural rubber / white carbon black masterbatch according to claim 1, characterized in that: The stirring speed in A2 is 10-500 rpm, and the stirring time is 10-60 min.

9. The natural rubber / white carbon black masterbatch according to claim 1, characterized in that: The flocculant added in A3 is one or more of formic acid, calcium chloride, methanol and protease.

10. The natural rubber / white carbon black masterbatch according to claim 1, characterized in that: The amount of the flocculant added in B1 is 0-1.0% of the dry weight of the natural rubber latex.

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