A method for preparing a rubber composition

Abstract

The application belongs to the field of rubber, and particularly discloses a preparation method of a rubber composition. The rubber composition is prepared by using a liquid-phase mixing method, so that reinforcing materials and additives in the rubber composition can be uniformly dispersed, and the rubber composition has good mechanical properties, high wear resistance, high wet grip performance, low rolling resistance, high safety and low cost.

Description

Technical Field

[0001] This invention belongs to the field of rubber, and specifically relates to a method for preparing a rubber composition. Background Technology

[0002] Traditional mixing methods involve using an internal mixer to break down rubber, reinforcing fillers, and additives into a uniformly dispersed mixture through shear forces. However, this method suffers from drawbacks such as high energy consumption, high pollution levels, and uneven dispersion.

[0003] The wet mixing process involves mixing filler emulsions and rubber emulsions using high-pressure spraying or similar methods before rubber coagulation. After dispersion in the liquid phase, the mixture undergoes coagulation and drying to obtain an elastomer composite material with reinforcing fillers. This composite material requires conventional mixing methods, where it is mixed with other additives under the shear force of an internal mixer to finally obtain the final compound rubber used in the production of semi-finished parts.

[0004] This wet mixing method does not fundamentally solve the problems of high energy consumption and high pollution in the rubber mixing process, and it also increases the number of steps and production costs.

[0005] Based on the above problems, this invention proposes a method for preparing a rubber composition. In this method, all or most of the fillers and additives required in rubber production are dispersed in water using a dispersant to form an emulsion. This emulsion is then liquid-phase mixed with the rubber emulsion, followed by coagulation, drying, and sheeting on an open mill to finally obtain the final rubber compound used for producing semi-finished parts. This rubber compounding technology can be integrated with rubber production, allowing for liquid-phase mixing of rubber with fillers and additives before coagulation. Following the normal rubber production steps, the final rubber compound is obtained, significantly reducing energy consumption in tire production, improving the performance of rubber composite materials, and being environmentally friendly and pollution-free, thus possessing significant application prospects. Summary of the Invention

[0006] In view of the drawbacks of the traditional rubber mixing methods mentioned above, such as high energy consumption, high pollution, and uneven dispersion, the present invention will provide a rubber composition and its preparation method.

[0007] To achieve the above objectives, the following technical solutions are specifically included:

[0008] A method for preparing a rubber composition, characterized in that the method comprises the following steps: S1, mixing and dispersing 10-150 parts of a mixture of silica and carbon black in any proportion, equivalent to 100 parts by weight of dry rubber in the final rubber compound, 1-30 parts of additive A, 1-80 parts of additive B, and 1-10 parts of dispersant with water in a certain proportion to obtain a mixture; S2, mixing the S1 mixture with a mixture of natural rubber latex, polybutadiene latex, and styrene-butadiene rubber latex in any proportion to obtain a mixture S2; S3, coagulating, dehydrating, and drying the mixture from step S2 to obtain rubber compound S3; S4, sheeting the rubber compound from step S3 using an open mill to obtain the final rubber compound. It is worth noting that the sulfur, accelerator, and scorch inhibitor in step S1 can also be added in step S4. Additive A includes: 0-20 parts silane coupling agent, 0.5-5 parts zinc oxide, 0.5-5 parts stearic acid, 0.3-8 parts antioxidant, and 0-3 parts protective wax. Additive B includes: 0-10 parts tackifying resin, 0-60 parts anti-slip resin, 0-20 parts tear-resistant resin, 0-40 parts processing oil, 0-10 parts cobalt salt, 0-5 parts binder, 0.5-8 parts sulfur, 0.5-5 parts accelerator, and 0.1-1 part scorching inhibitor.

[0009] The dispersant comprises one or more of the following chemical structural formulas in any proportion: (R1COO) x M, [R1O(R2O)] n -COO] x M, R1OSO3M, R1O(R2O) n -SO3M, R1SO4M, R1O(R2O) n -SO4M,C3H5O3H 3-x (COR1) x C6H 14 O6H 6-x (COR1) x R1COO(R2O) n , R1O(R2O) n H, R1SiOR2. Where R1 is a C5-C20 alkyl, cycloalkyl, aromatic, or substituted aromatic group. R2 is a C1-C8 alkyl group. M is a metallic element. n is an integer from 1 to 20. x is an integer from 1 to 3.

[0010] The uniform mixing and dispersion in step S1 can be achieved through high-speed emulsification or high-speed stirring.

[0011] The solid content of the natural rubber latex, polyisoprene latex, polybutadiene latex, and styrene-butadiene rubber latex is 5-80%.

[0012] In step S1, the solid content of the mixture is 5-60%. Preferably, the solid content of the mixture is 7-20%.

[0013] The rubber compound in step S4 can be mixed in an internal mixer and then sheeted out by a two-roll mill, or it can be sheeted out directly by a two-roll mill.

[0014] Compared with the prior art, the present invention has the following beneficial effects: the preparation method of the rubber composition of the present invention has low energy consumption and is environmentally friendly. The fillers and additives in the obtained rubber composition are evenly dispersed, and it has the characteristics of good mechanical properties, high wear resistance, high wet grip performance, low rolling resistance, high safety and low cost. Attached Figure Description Figure 1 This is a flowchart of the method for preparing rubber compositions. Detailed Implementation

[0015] To better illustrate the purpose, technical solution, and advantages of this invention, specific embodiments will be used to further explain the invention below. Unless otherwise specified, the test methods used in the embodiments and / or comparative examples are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available.

[0016] Natural rubber latex: purchased from Hainan Rubber Jinxiang Company;

[0017] Styrene-butadiene rubber latex: purchased from Daqing Petrochemical Company of China National Petroleum Corporation;

[0018] Silane coupling agent: Si69, commercially available;

[0019] Dispersants: Sodium oleate (commercially available); AEO-10 ​​(commercially available); Sodium alkylbenzene sulfonate (commercially available);

[0020] Carbon black: N330, commercially available;

[0021] Silica: 165MP, commercially available;

[0022] Slip-resistant resin: CSR6373, Shanghai Qixiang New Material Technology Co., Ltd.;

[0023] Tear-resistant resin: CSR200, Shanghai Qixiang New Material Technology Co., Ltd.;

[0024] Tackifying resin: K-22, Shanghai Qixiang New Material Technology Co., Ltd.;

[0025] Anti-aging agent 4020, commercially available;

[0026] Anti-aging agent RD, commercially available;

[0027] Protective wax, commercially available;

[0028] Sulfur, commercially available;

[0029] Accelerator: Vulcanization accelerator NS, commercially available;

[0030] Anti-scorching agent: CTP, commercially available.

[0031] Example 1

[0032] A method for preparing a rubber composition, characterized in that the method comprises the following steps: S1, 60 parts of carbon black N234 (equivalent to 100 parts by weight of dry rubber in the final compound), 9.5 parts of additive A, and 3.1 parts of additive B, mixed with water at a weight ratio of 1:10, are ground and emulsified at high speed using a grinding and emulsifying machine to prepare a mixture; S2, the mixture in S1 is mixed with a natural rubber latex with a solid content of 60% at a ratio of 1:4.3 to obtain a mixture S2; S3, the mixture in step S2 is coagulated, dehydrated, and dried to obtain a rubber compound S3; S4, the rubber compound in step S3 is sheeted using an open mill to obtain the final compound of the rubber composition. Additive A comprises: 3 parts zinc oxide, 2 parts stearic acid, 2 parts antioxidant 6PPD, 1.5 parts antioxidant RD, and 1 part protective wax. Additive B includes: 1.4 parts sulfur, 1.5 parts accelerator, and 0.2 parts scorch inhibitor.

[0033] The final rubber compound was vulcanized at 150°C and its mechanical properties were tested.

[0034] Comparative Example 1

[0035] The preparation method of the rubber composition of Comparative Example 1 includes the following steps: S1, 100 parts of natural rubber are added to a mixer according to the proportion, pressurized for 20-60 seconds, all carbon black, tackifying resin, zinc oxide, stearic acid and antioxidant are added by lifting the plug, pressurized for 20-60 seconds, lifted the plug for 5-35 seconds, pressurized to 130-170 degrees to discharge rubber, sheet out, and cool for 2-20 hours. The speed of the mixer is 30-70 rpm, and the pressure of the top plug is 60-120 Bar to obtain the first stage masterbatch.

[0036] S2. Add the first stage of masterbatch obtained in step S1 into a Banbury mixer, and simultaneously add some carbon black and silica or a mixture of both in any proportion. Pressurize for 30-80 seconds, lift the plug for 5-25 seconds, pressurize to 130-160 degrees Celsius, hold for 30-90 seconds, lift the plug for 5-25 seconds, pressurize to 130-160 degrees Celsius, hold for 30-90 seconds, lift the plug for 5-25 seconds, pressurize to 130-160 degrees Celsius to produce sheets, cool for 2-20 hours, the Banbury mixer speed is 30-70 rpm, and the top plug pressure is 60-120 Bar to obtain the second stage of masterbatch.

[0037] S3. Add the second stage of masterbatch obtained in step S2 into the internal mixer, along with sulfur, accelerator and anti-scorching agent. Pressurize for 20-50 seconds, lift the plug for 5-25 seconds, pressurize for 20-50 seconds, lift the plug for 5-25 seconds, pressurize for 20-50 seconds, lift the plug for 5-25 seconds, pressurize to 100-120 degrees, discharge the rubber, sheet it out and cool it. The speed of the internal mixer is 20-50 rpm and the pressure of the top plug is 120-160 Bar to obtain the final rubber.

[0038] Examples 2-7

[0039] The difference between Examples 2-7 and Example 1 is that the fillers and additives are dispersed in water using a dispersant, as detailed in Table 1.

[0040] Comparative Examples 2-4

[0041] The preparation methods of the rubber compositions in Comparative Examples 2-4 were the same as those in Comparative Example 1. The difference between Comparative Examples 1-4 and Examples 1-7 lies in the preparation methods of the rubber compositions. The rubber compositions in Examples 1-7 were prepared by liquid-phase mixing, while those in Comparative Examples 1-4 were prepared by internal mixer mixing.

[0042] Table 1

[0043]

[0044]

[0045] The rubber compositions prepared in the above examples and comparative examples were subjected to performance tests, and the test results are shown in Table 2.

[0046] The performance testing method is as follows:

[0047] (1) 300% elongation: Tested according to GB / T 528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber;

[0048] (2) Tensile strength: Tested according to GB T 528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber;

[0049] (3) Tear strength: Tested according to GB / T 529-2008 Determination of tear strength of vulcanized rubber or thermoplastic rubber (trouser-shaped, right-angled and crescent-shaped specimens);

[0050] (4) DIN abrasion: Tested according to GB / T 9867-2008 Determination of abrasion resistance of vulcanized rubber or thermoplastic rubber (rotary roller abrasion tester method);

[0051] (5) The wet performance index Tan0℃ (the larger the index, the larger the tanδ, and the better the wet grip performance): tested according to ECE R117 ANNEX5;

[0052] (6) Rolling resistance index Tan60℃ (the smaller the index, the smaller the tanδ, and the better the rolling resistance): Tested according to ISO28580-2018 (Chinese translation) Method for measuring rolling resistance of passenger car and truck tires.

[0053] Table 2

[0054]

[0055] As can be seen from Examples 2-7 and Comparative Examples 1-4, compared with Examples 2-7, Comparative Examples 1-4 adopted the traditional internal mixer mixing method, while the present invention uses the liquid phase mixing method, which can promote filler dispersion, improve the mechanical properties of rubber, reduce the filler Payne effect, reduce the hysteresis loss of rubber compound and improve the wet skid resistance of rubber compound.

[0056] As can be seen from Examples 1 and 2, dispersants can significantly promote the dispersion of additives, improve the mechanical properties of rubber, and reduce the hysteresis loss of rubber compounds.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a rubber composition, characterized in that... The preparation method of the rubber composition includes the following steps: S1, mixing 10-150 parts of a mixture of silica and carbon black in any proportion, equivalent to 100 parts by weight of dry rubber in the final rubber compound, 1-30 parts of additive A, 1-80 parts of additive B, and 0.2-10 parts of dispersant with water in a certain proportion to obtain a mixture; S2, mixing the S1 mixture with a mixture of natural rubber latex, polybutadiene latex, polyisoprene latex, and styrene-butadiene rubber latex in any proportion to obtain a mixture S2; S3, coagulating, dehydrating, and drying the mixture from step S2 to obtain rubber compound S3; S4, sheeting the rubber compound from step S3 using an open mill to obtain the final rubber compound of the rubber composition. It is worth noting that the sulfur, accelerator, and scorch inhibitor in step S1 can also be added in step S4. Additive A includes: 0-20 parts silane coupling agent, 0.5-5 parts zinc oxide, 0.5-5 parts stearic acid, 0.3-8 parts antioxidant, and 0-3 parts protective wax. Additive B includes: 0-10 parts tackifying resin, 0-60 parts anti-slip resin, 0-20 parts tear-resistant resin, 0-40 parts processing oil, 0-10 parts cobalt salt, 0-5 parts binder, 0.5-8 parts sulfur, 0.5-5 parts accelerator, and 0.1-1 part scorching inhibitor.

2. The rubber composition according to claim 1, characterized in that... The dispersant comprises one or more of the following chemical structural formulas in any proportion: (R1COO) x M, [R1O(R2O)] n -COO] x M, R1OSO3M, R1O(R2O) n -SO3M, R1SO4M, R1O(R2O) n -SO4M,C3H5O3H 3-x (COR1) x C6H 14 O6H 6-x (COR1) x R1COO(R2O) n , R1O(R2O) n H, R1SiOR2. Where R1 is a C5-C20 alkyl, cycloalkyl, aromatic, or substituted aromatic group. R2 is a C1-C8 alkyl group. M is a metallic element. n is an integer from 1 to 20. x is an integer from 1 to 3.

3. The method for preparing a rubber composition according to claim 1, characterized in that... The uniform mixing and dispersion in step S1 can be achieved through high-speed emulsification or high-speed stirring.

4. The method for preparing a rubber composition according to claim 1, characterized in that... In step S1, the silica, carbon black, dispersant, additive A, and additive B can be liquids, solid powders, or solid particles. Solid particles require pulverization before mixing and dispersing with water.

5. The method for preparing a rubber composition according to claim 1, characterized in that... The solid content of the natural rubber latex, polyisoprene latex, polybutadiene latex, and styrene-butadiene rubber latex is 5-80%.

6. The rubber composition according to claim 1, characterized in that... The solid content of the mixture in step S1 is 5-60%.

7. The rubber composition according to claim 1, characterized in that... The rubber compound in step S4 can be re-milled in an internal mixer and then sheeted out on a two-roll mill, or it can be sheeted out directly from the two-roll mill.

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