Dynamic cutting-resistant rubber composition and preparation method thereof

Abstract

The invention belongs to the technical field of rubber, and relates to a dynamic cutting-resistant rubber composition and a preparation method thereof, and the dynamic cutting-resistant rubber composition is prepared from the following raw materials in parts by weight: 100 parts of diene rubber, 5.0 to 150.0 parts of white carbon black, 0.25 to 37.5 parts of silane coupling agent M, 0 to 80.0 parts of carbon black, 0.5 to 6.0 parts of zinc oxide, 0.5 to 3.0 parts of stearic acid, 0.5 to 5.0 parts of anti-aging agent, 0.5 to 4.0 parts of protective wax, 0 to 40.0 parts of operating oil, 0.5 to 4.0 parts of sulfur and 0.5 to 4.0 parts of accelerant. The silane coupling agent M is used in the rubber composition, a flexible chain of the silane coupling agent M reduces the Tg point of a rubber material, and the dynamic cutting resistance of the formula at low temperature is improved, so that the use performance of a tire in a low-temperature environment is favorably improved; the invention also provides a preparation method of the dynamic cutting-resistant rubber, and a mixed rubber material with stable performance and good repeatability is prepared by using a specific mixing process and an open mixing technique.

Description

Technical Field

[0001] The invention belongs to the technical field of rubber, and relates to a rubber composition for tire tread rubber, and in particular to a dynamic cut-resistant rubber composition and a preparation method thereof. Background Art

[0002] With the development trend of greening and functionalization of the tire industry, reducing tire rolling resistance and improving tire anti-skid performance have become research hotspots in the rubber industry. Silica-filled rubber has low rolling resistance and anti-skid performance that carbon black does not have, so it has become another major rubber reinforcing agent after carbon black.

[0003] The dispersibility of white carbon black and the performance of its functions require the participation of silane coupling agents. Silane coupling agents modify the surface of white carbon black, play a bridging role between white carbon black and polymers, improve the filler network, and enhance the coupling effect between fillers and polymers, thereby enhancing the compatibility between fillers and polymers and improving the processing performance and mechanical properties of rubber products. Silane coupling agents have become a rapidly developing auxiliary agent after white carbon black became a rubber reinforcing agent. At present, the silane coupling agents mainly used in the tire industry are divided into traditional polysulfide silanes and new mercapto silanes. The focus is on improving the interaction with white carbon black and enhancing the interaction with polymers, so as to achieve the purpose of reducing rolling resistance and improving anti-skid performance. The optimization and improvement of other properties need to be achieved through other means.

[0004] There are many factors that affect the performance and service life of tire rubber products, including internal factors of the product and external environmental factors. On the one hand, the selection of raw rubber types and proportions, the use of functional additives, etc. during formula design will affect the performance of rubber tires and rubber products. On the other hand, the use environment will also affect the service life of tire rubber products. my country has a vast territory, and there are large differences in temperature and humidity between the north and south regions and the four seasons. After the northern region enters winter, the temperature is basically below 0℃, and after the southern region enters summer, the temperature is basically above 30℃. The high and low temperature characteristics of rubber will directly affect the performance and service life of tire rubber products, such as tread cracks caused by low temperature, irregular precipitation caused by the intensified movement of small molecules at high temperature (such as frost spraying and coloring), etc.

[0005] Under harsh usage conditions, such as use in low temperature areas, high speeds, large loads, and poor road conditions, the tires are severely punctured and cut, and are damaged quickly. The problems of cut resistance and tread chipping are more prominent. Therefore, providing a rubber composition with excellent dynamic cut resistance is of great significance for extending the service life of the tire. Summary of the invention

[0006] In view of the deficiencies in the prior art, the object of the present invention is to provide a dynamic cut-resistant rubber composition. The rubber composition of the present invention uses a silane coupling agent M, whose flexible chain reduces the Tg point of the rubber, and the dynamic cut resistance of the formula at low temperatures is improved, which will help to improve the performance of the tire in a low temperature environment; the present invention also provides a method for preparing the above-mentioned dynamic cut-resistant rubber, by using a specific mixing process and open mixing technique, a mixed rubber with stable performance and good repeatability is prepared.

[0007] The present invention is achieved through the following technical solutions:

[0008] A dynamic cut-resistant rubber composition, which is composed of the following raw materials in parts by weight:

[0009] 100 parts of diene rubber, 5.0-150.0 parts of white carbon black, 0.25-37.5 parts of silane coupling agent M, 0-80.0 parts of carbon black, 0.5-6.0 parts of zinc oxide, 0.5-3.0 parts of stearic acid, 0.5-5.0 parts of antioxidant, 0.5-4.0 parts of protective wax, 0-40.0 parts of operating oil, 0.5-4.0 parts of sulfur, and 0.5-4.0 parts of accelerator.

[0010] A further improvement of the present invention is:

[0011] The diene rubber has a dynamic cutting resistance mass source loss of 1-8 g.

[0012] The dynamic cutting resistance mass source loss of the diene rubber of the present invention is defined as:

[0013] The diene rubber can be one or a combination of two or more of natural rubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber, nitrile rubber, etc. The dynamic cutting resistance mass source loss data is obtained by mixing and vulcanizing the sample after mixing 100 parts of diene rubber, 3 parts of zinc oxide, 2 parts of stearic acid, 1.5 parts of sulfur and 1.5 parts of accelerator.

[0014]

[0015] The structural formula of the silane coupling agent M is as follows:

[0016]

[0017] Wherein, R1 is a methyl polymerized glycol ethoxy group with a molecular weight of 200 to 400 g / mol, R2 is an ethoxy group or a methyl polymerized glycol ethoxy group with a molecular weight of 200 to 400 g / mol, and X=2 to 6.

[0018] Furthermore, the diene rubber is one or a mixture of two or more of natural rubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber or nitrile rubber;

[0019] And / or, the protective wax is high temperature protective wax OK11018;

[0020] And / or, the antioxidant is an amine antioxidant 6PPD or a quinoline antioxidant TMQ;

[0021] And / or, the environmentally friendly oil is environmentally friendly aromatic oil E350;

[0022] And / or, the accelerator is a delayed-effect accelerator TBBS or a guanidine accelerator DPG;

[0023] And / or, the stearic acid is octadecanoyl stearic acid;

[0024] And / or, the white carbon black is highly dispersed white carbon black CSHD160;

[0025] And / or, the carbon black is medium-super wear-resistant furnace black N234;

[0026] Furthermore, the specific surface area of ​​the white carbon black is 10 to 500 m 2 / g.

[0027] Furthermore, the average particle size of the carbon black is 10 to 500 nm.

[0028] A further improvement of the present invention is:

[0029] A method for preparing a dynamic cut-resistant rubber composition, characterized in that it comprises the following steps:

[0030] One-stage mixing: Diene rubber, white carbon black, carbon black, silane coupling agent M, stearic acid, antioxidant 4020 and RD, and protective wax are put into an internal mixer according to the mass ratio for mixing. When the temperature reaches a certain temperature, the top bolt is raised, and environmentally friendly oil is put into the internal mixer to continue mixing. After the top bolt is raised and cleaned, the temperature is controlled and mixed. The discharge door is opened to discharge the rubber material, and the sheet is unloaded using the open mixer to obtain a first-stage mixed rubber;

[0031] Second stage mixing: put the first stage mixed rubber and zinc oxide into the internal mixer, after mixing, raise the top bolt to clean, continue to control the temperature and mix, raise the top bolt to clean, continue to mix, open the discharge door, discharge the rubber, use the open mixer to unload the sheet, and obtain the second stage mixed rubber;

[0032] Final refining: After the second-stage mixed rubber is put into the internal mixer with sulfur and accelerator for mixing, the top bolt is raised for cleaning and mixing is continued. After the weight is lifted, the temperature is controlled and mixed. Finally, the discharge door is opened to discharge the rubber material and the sheet is unloaded using the open mixer to obtain a dynamic cut-resistant rubber composition.

[0033] Furthermore, in one stage of mixing, the mixing speed is 75-85 rpm, and the time is 30-40 s; when the temperature is raised to 100-130°C, the top bolt is raised, and the mixing speed is continued to be 65-75 rpm, and the time is 35-45 s; the temperature-controlled mixing speed is 50-60 rpm, the temperature is 140-150°C, and the time is 50-70 s.

[0034] Furthermore, in the second stage mixing, the mixing speed is 40-50 rpm, and the time is 20-40 s; the temperature-controlled mixing speed is 60-70 rpm, the temperature is 135-145° C., and the time is 50-70 s; and the continued mixing time is 20-40 s.

[0035] Furthermore, in the final kneading, the kneading speed is 40-50 rpm, and the time is 20-40 s; the continued kneading time is 20-40 s; the temperature of the temperature-controlled kneading is 95-100° C., and the time is 20-40 s.

[0036] Furthermore, the process of unrolling the rubber sheet on the mixing mill is as follows: the speed ratio of the front and rear rollers of the mixing mill is set to 1:1.15-1.3, the temperature difference between the front and rear rollers is 5-15°C, the roller distance is set to 1.5mm, after the rubber material is wrapped around the roller, the left and right 3 / 4 cutters are used 5 times each to cut and remove the rubber material, the roller distance is set to 0.5mm, a thin pass of rubber material is added, and triangular packages and rolls are alternately made 5 times each, and finally the rolled rubber material is placed in the roller in a direction parallel to the axis of the roller for unrolling, so as to stabilize the orientation of the rubber material under the action of shear force, and the rubber sheet after unrolling is spread flat on a smooth and clean workbench to avoid uneven pulling deformation caused by the weight of the rubber material during hanging.

[0037] The beneficial effects of the present invention are:

[0038] The stearic acid and zinc oxide used in the present invention form an activation system in a sulfur vulcanization system, which mainly functions to activate the vulcanization system. The two interact with each other to generate zinc soap, thereby increasing the solubility of zinc oxide in rubber and reacting with an accelerator to form a complex with good solubility in rubber, thereby activating the accelerator and sulfur and improving the vulcanization efficiency. The antioxidant and protective wax used mainly function to increase the physical and chemical protection of rubber and prevent the rubber macromolecules from being damaged by aging due to physical and chemical factors. The operating oil used mainly functions to improve processability. The sulfur and accelerator used together form a sulfur vulcanization system.

[0039] The present invention adds a silane coupling agent M with a flexible macromolecular long-chain structure during the rubber processing process, and utilizes the characteristics of the flexible chain with good low-temperature softness and compliance to enable the rubber to obtain a low Tg point, and improve the dynamic cutting resistance of the formula at low temperatures, which will help to improve the performance of the tire in a low-temperature environment; at the same time, the macromolecular long-chain structure enhances the adsorption of small molecular substances, and can dynamically control the migration speed of protective wax, oil, etc., so that the migration and discoloration resistance of the rubber is improved, thereby improving the discoloration phenomenon of the rubber, which will help to improve the appearance of the tire.

[0040] The invention adopts a specific rubber compound mixing process and an open mixing method to ensure sufficient silanization reaction and prepare a mixed rubber compound with stable performance and good repeatability. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is the result of the discoloration resistance test. DETAILED DESCRIPTION

[0042] The present invention is described in detail below in conjunction with specific embodiments.

[0043] The rubber composition was prepared by mixing as follows:

[0044] One-stage mixing: put the raw rubber, white carbon black, carbon black, silane coupling agent M, stearic acid, antioxidant 4020 and RD, and protective wax into the internal mixer according to the mass ratio and mix them at 80rpm for 30-40s. When the mixing temperature reaches 120℃, raise the top bolt and put E350 into the internal mixer. Mix at 70rpm for 40s. After raising the top bolt and cleaning it, control the mixing temperature at 140-150℃ at 55rpm. Continue mixing for 60s, then open the discharge door, discharge the rubber, use the open mixer to unload the sheet, and set the front and rear roller speeds of the open mixer. The ratio is 1:1.15~1.3, the temperature difference between the front and rear rollers is 5~15℃, the roller distance is set to 1.5mm, after the rubber is wrapped around the roller, use the rubber cutting knife to cut 3 / 4 of the left and right for 5 times each, cut and remove the rubber, set the roller distance to 0.5mm, add a thin pass of rubber, alternately make triangle packages and roll them 5 times each, and finally put the rolled rubber into the roller in a direction parallel to the axis of the roller for unrolling, so as to stabilize the orientation of the rubber under the action of shear force. After unrolling, the rubber sheet is spread flat on a smooth and clean workbench to avoid uneven pulling and deformation caused by the weight of the rubber when hanging.

[0045] Second stage mixing: put the first stage mixed rubber and zinc oxide into the internal mixer, mix at 45rpm for 30s, raise the top bolt for cleaning, control the mixing temperature at 135-145℃ at 65rpm, mix for 60s, raise the top bolt for cleaning, continue mixing for 30s, open the discharge door, discharge the rubber, use the open mixer to unload the sheet, set the front and rear roller speed ratio of the open mixer to 1:1.15-1.3, the front and rear roller temperature difference to 5-15℃, and the roller distance to 1.5 mm, after the rubber is wrapped around the roller, use the rubber cutting knife to cut 3 / 4 of the left and right for 5 times each to cut and remove the rubber, set the roller distance to 0.5mm, add a thin pass of rubber, alternately make triangle packages and roll them 5 times each, and finally put the rolled rubber into the roller in a direction parallel to the axis of the roller for unrolling, so as to stabilize the orientation of the rubber under the action of shear force. After unrolling, lay the rubber flat on a smooth and clean workbench to avoid uneven pulling and deformation caused by the weight of the rubber when hanging.

[0046] Final refining: put the second-stage mixed rubber, sulfur and accelerator into the internal mixer, mix at a speed of 45rpm for 30s, raise the top bolt for cleaning and continue mixing for 30s, control the mixing temperature at 95-100℃ after lifting the weight, open the unloading door after continuing to mix for 30s, discharge the rubber, and use the open mixer to unload the rubber. Set the front and rear roller speed ratio of the open mixer to 1:1.15-1.3, the temperature difference between the front and rear rollers to 5-15℃, and the roller distance to 1.5mm. After the rubber is wrapped around the roller, use the rubber cutting knife to cut the left and right 3 / 4 cutters 5 times each to cut and remove the rubber, set the roller distance to 0.5mm, add the rubber thin pass, alternately make triangular packages and rolls 5 times each, and finally put the rolled rubber into the roller in a direction parallel to the roller axis for unloading, so as to stabilize the orientation of the rubber under the action of shear force. The rubber after unloading is spread flat on a smooth and clean workbench to avoid uneven pulling and deformation caused by the weight of the rubber when hanging.

[0047] The weight compositions of the rubber compositions are as follows:

[0048] Material Name Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Example 2 Example 3 Natural rubber 100 100 Butadiene rubber 30 30 Styrene Butadiene Rubber 96 100 96 100 Carbon Black N234 35 40 35 40 White carbon black CSHD160 80 15 10 80 15 10 Si69 6.4 1.2 0.8 Silane coupling agent M 6.4 1.2 0.8 E350 10.0 10.0 Zinc Oxide 3.0 3.0 5.0 3.0 3.0 5.0 Stearic acid 2.0 2.0 2.0 2.0 2.0 2.0 Antioxidant 6PPD 1.5 1.5 2.0 1.5 1.5 2.0 Antioxidant TMQ 1.0 1.0 1.0 1.0 1.0 1.0 Protective wax 1.0 1.0 1.5 1.0 1.0 1.5 S 1.5 1.1 1.4 1.5 1.1 1.4 Accelerator TBBS 1.5 1.4 1.2 1.5 1.4 1.2 DPG 2.0 2.0

[0049] The structural formula of the silane coupling agent M used in the embodiment is:

[0050]

[0051] Silane coupling agent M is a product sold by our company, product number: Qixiang si769;

[0052] The rubber compounds prepared by the comparative formulation and the embodiment formulation were tested according to the following standards:

[0053] Vulcanization performance test: Refer to GB / T 16584-1996 to test the vulcanization performance of the rubber compound;

[0054] Mechanical properties test: Tested according to GB / T528-2009.

[0055] Vulcanized rubber hardness: hardness test shall be carried out according to GBT531.1-2008.

[0056] Hot air aging test is based on GB / T 3512-2014 "Hot air accelerated aging of vulcanized rubber or thermoplastic rubber

[0057] Heat resistance test》Test conditions: 100℃×72h, 5 samples are used for each test, and the median value is taken as the test result.

[0058] DIN Abrasion: Abrasion test is conducted in accordance with GBT 9867-2008 “Determination of wear resistance of vulcanized rubber or thermoplastic rubber (rotating roller abrasion machine method)”.

[0059] DMA test: Dynamic mechanical analysis is used to test the vulcanized rubber. The test conditions are: the test mode is tensile mode, the dynamic strain is 0.25%, the static strain is 1%, and the heating rate is 3K / min. The smaller the 60℃ tanδ value, the lower the heat generation value of the tread rubber.

[0060] Cutting resistance test: Cutting loss test principle: Use a specially designed cutter head to repeatedly impact the rotating round rubber sample with a certain amount of energy. Simulate the tire hitting a sharp object with considerable force, the surface is cut, and simulate the tire tread on a rough and sharp road surface, cutting, tearing, and breaking caused by traction or braking. The cutting loss is expressed by the weight difference between the rubber sample before and after the test, and is implemented according to the enterprise standard. The speed is 720r / min, the impact frequency is 120 / min, and the test time is 10min. The lower the cutting loss value, the better the cutting resistance. Using a liquid nitrogen temperature control device, the test environment temperature is set to -20±3℃.

[0061] Discoloration resistance test: Wrap the tensile test piece with cellophane on top and bottom and then vulcanize it. Then place it in a 40℃ oven for 30 days and observe the color change of the film or cellophane. The difference in color change of the film surface or cellophane is used to measure the film's resistance to small molecule migration. The smaller the color change, the better the discoloration resistance.

[0062] The test results are shown in the following table and attached figure:

[0063]

[0064]

[0065] It can be seen from the comparative examples and the embodiments that the mechanical test results show that when the silane coupling agent M of the present invention is used, the 300% modulus stress is slightly decreased, the tensile strength is slightly increased, the loss factor tanδ at 60°C is significantly reduced, and the dynamic cutting resistance at low temperature is significantly improved.

[0066] The discoloration resistance test results are as follows Figure 1 As shown, in the formulation of oil-containing or oil-filled adhesive, by using the silane coupling agent M of the present invention, the degree of contamination of the film on the transparent glass paper is reduced, and the discoloration resistance of the film is improved.

[0067] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A dynamic cut-resistant rubber composition, characterized in that: It is composed of the following raw materials in parts by weight: 100 parts of diene rubber, 5.0-150.0 parts of white carbon black, 0.25-37.5 parts of silane coupling agent M, 0-80.0 parts of carbon black, 0.5-6.0 parts of zinc oxide, 0.5-3.0 parts of stearic acid, 0.5-5.0 parts of antioxidant, 0.5-4.0 parts of protective wax, 0-40.0 parts of operating oil, 0.5-4.0 parts of sulfur, and 0.5-4.0 parts of accelerator.

2. A dynamic cut-resistant rubber composition according to claim 1, characterized in that: The structural formula of the silane coupling agent M is as follows: Wherein, R1 is a methyl polymerized glycol ethoxy group with a molecular weight of 200 to 400 g / mol, R2 is an ethoxy group or a methyl polymerized glycol ethoxy group with a molecular weight of 200 to 400 g / mol, and X=2 to 6.

3. A dynamic cut-resistant rubber composition according to claim 1, characterized in that: The diene rubber has a dynamic cutting resistance mass source loss of 1-8 g.

4. A dynamic cut-resistant rubber composition according to claim 1, characterized in that: The diene rubber is one or a mixture of two or more of natural rubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber or nitrile rubber; And / or, the protective wax is high temperature protective wax OK11018; And / or, the antioxidant is an amine antioxidant 6PPD or a quinoline antioxidant TMQ; And / or, the environmentally friendly oil is environmentally friendly aromatic oil E350; And / or, the accelerator is a delayed-effect accelerator TBBS or a guanidine accelerator DPG; And / or, the stearic acid is octadecanoyl stearic acid; And / or, the white carbon black is highly dispersed white carbon black CSHD160; And / or, the carbon black is medium super wear-resistant furnace black N234.

5. The dynamic cut-resistant rubber composition according to claim 1, characterized in that: The specific surface area of ​​the white carbon black is 10 to 500 m 2 / g.

6. A dynamic cut-resistant rubber composition according to claim 1, characterized in that: The average particle size of the carbon black is 10 to 500 nm.

7. A method for preparing a dynamic cut-resistant rubber composition according to claims 1 to 6, characterized in that: The following steps are involved: One-stage mixing: Diene rubber, white carbon black, carbon black, silane coupling agent M, stearic acid, antioxidant 4020 and RD, and protective wax are put into an internal mixer according to the mass ratio for mixing. When the temperature reaches a certain temperature, the top bolt is raised, and environmentally friendly oil is put into the internal mixer to continue mixing. After the top bolt is raised and cleaned, the temperature is controlled and mixed. The discharge door is opened to discharge the rubber material, and the sheet is unloaded using the open mixer to obtain a first-stage mixed rubber; Second stage mixing: put the first stage mixed rubber and zinc oxide into the internal mixer, after mixing, raise the top bolt to clean, continue to control the temperature and mix, raise the top bolt to clean, continue to mix, open the discharge door, discharge the rubber, use the open mixer to unload the sheet, and obtain the second stage mixed rubber; Final refining: After the second-stage mixed rubber is put into the internal mixer with sulfur and accelerator for mixing, the top bolt is raised for cleaning and mixing is continued. After the weight is lifted, the temperature is controlled and mixed. Finally, the discharge door is opened to discharge the rubber material and the sheet is unloaded using the open mixer to obtain a dynamic cut-resistant rubber composition.

8. The method for preparing a dynamic cut-resistant rubber composition according to claim 7, characterized in that: In the first stage of mixing, the mixing speed is 75-85 rpm, and the time is 30-40 s; when the temperature is raised to 100-130°C, the top bolt is raised, and the mixing speed is continued at 65-75 rpm, and the time is 35-45 s; the temperature-controlled mixing speed is 50-60 rpm, the temperature is 140-150°C, and the time is 50-70 s.

9. The method for preparing a dynamic cut-resistant rubber composition according to claim 7, characterized in that: In the second stage mixing, the mixing speed is 40-50 rpm, and the time is 20-40 s; the temperature-controlled mixing speed is 60-70 rpm, the temperature is 135-145° C., and the time is 50-70 s; and the continued mixing time is 20-40 s.

10. The method for preparing a dynamic cut-resistant rubber composition according to claim 7, characterized in that: In the final kneading, the kneading speed is 40-50 rpm, and the time is 20-40 s; the continued kneading time is 20-40 s; the temperature of the temperature-controlled kneading is 95-100° C., and the time is 20-40 s.

11. The method for preparing a dynamic cut-resistant rubber composition according to claim 7, characterized in that: The process of unrolling the rubber sheet on the mixing mill is as follows: the speed ratio of the front and rear rollers of the mixing mill is set to 1:1.15-1.3, the temperature difference between the front and rear rollers is 5-15°C, the roller distance is set to 1.5mm, after the rubber material is wrapped around the roller, the left and right 3 / 4 cutters are used 5 times each to cut and remove the rubber material, the roller distance is set to 0.5mm, a thin pass of rubber material is added, and triangular wrapping and rolling are alternately performed 5 times each, and finally the rolled rubber material is placed in the roller in a direction parallel to the axis of the roller for unrolling, so as to stabilize the orientation of the rubber material under the action of shear force, and the rubber sheet after unrolling is spread flat on a smooth and clean workbench to avoid uneven pulling deformation caused by the weight of the rubber material when hanging.

Images