A tire tread rubber composition and a method for producing the same

Abstract

The application discloses a tire tread rubber composition and a preparation method thereof, and belongs to the technical field of tires. The tire tread rubber composition comprises the following raw material components in parts by weight: 45-60 parts of first rubber, 55-75 parts of second rubber, 25-35 parts of carbon black, 8-12 parts of modified alkyl phenolic resin, 5-8 parts of adhesive RA, 3-5 parts of antioxidant, 1-3 parts of vulcanizing agent, and 0.5-2 parts of accelerator; the first rubber is natural rubber SPR10 or natural rubber SVR3L; the second rubber is one or two of solution polymerized styrene butadiene rubber, isoprene rubber and brominated butyl rubber; and the weight ratio of the first rubber to the second rubber is (0.8-1):1. The tire tread rubber composition and the preparation method thereof introduce the modified alkyl phenolic resin into the rubber composition, enhance the adhesion between the rubber and the steel wire cord, avoid the occurrence of the blooming phenomenon, and improve the tire durability.

Description

Technical Field

[0001] This application relates to a tire tread rubber composition and its preparation method, belonging to the field of tire technology. Background Technology

[0002] With the rapid development of new energy vehicles, the tire industry, which supports them, is also facing increasingly stringent requirements for high performance. Despite the rapid pace of automotive upgrades and changes, cars still rely on rubber tires to handle driving and braking processes, and the lifespan of tires significantly impacts the user experience and the reputation of car brands.

[0003] All-steel radial truck tires with rigid belt layers, bead layers, and flexible carcasses have excellent performance. The carcass, as its main component, plays a role in bearing the internal pressure of the tire and buffering the impact and vibration of the road surface. Therefore, the carcass is required to have sufficiently high strength, which depends on the strength and density of the carcass steel cord and the adhesion performance between the tread and the steel cord. The carcass steel cord rubber compound must not only have sufficient strength itself, but also combine the hard steel cord with the soft rubber.

[0004] Currently, to improve the adhesion between the rubber compound and the steel cord, resorcinol or resorcinol-formaldehyde precondensation resin is usually added to the tire carcass compound. However, the addition of these rubber additives can cause blooming on the surface of the rubber compound. This is mainly due to the migration and precipitation of sulfur in the rubber composition on the rubber surface, which reduces the surface adhesion and tack retention rate of the rubber, resulting in poor durability of the finished tire and quality problems such as tire shoulder gaps and delamination. Summary of the Invention

[0005] To address the aforementioned issues, a tire tread rubber composition and its preparation method are provided. By introducing modified alkylphenol resin into the rubber composition, the adhesion between the rubber and the steel cord is enhanced, while blooming is avoided, thereby improving tire durability.

[0006] The technical solution adopted in this invention is as follows:

[0007] According to one aspect of this application, a tire tread rubber composition is provided, comprising, by weight, the following raw material components: 45-60 parts of a first rubber, 55-75 parts of a second rubber, 25-35 parts of carbon black, 8-12 parts of modified alkylphenol resin, 5-8 parts of adhesive RA, 3-5 parts of antioxidant, 1-3 parts of vulcanizing agent, and 0.5-2 parts of accelerator.

[0008] The first rubber is natural rubber SPR10 or natural rubber SVR3L, and the second rubber is one or two of solution-polymerized styrene-butadiene rubber, isoprene rubber, and brominated butyl rubber. The weight ratio of the first rubber to the second rubber is (0.8-1):1.

[0009] Optionally, the preparation method of the modified alkylphenol resin includes the following steps:

[0010] (1) Dissolve octylphenol in toluene, add acidic catalyst and formaldehyde solution in sequence, and stir at 80-100℃ for 2-4h to obtain the first alkylphenol resin. Then add alkaline catalyst and react the first alkylphenol resin with formaldehyde solution at 100-120℃ for 1-3h to obtain the second alkylphenol resin.

[0011] (2) Petroleum resin and acrylic acid are reacted at 190-200℃ for 2-3 hours, and then a second alkylphenol resin is added to the obtained reaction product and a Diels-Alder addition reaction is carried out at 180-230℃ to obtain a modified alkylphenol resin.

[0012] Optionally, the molecular weight of the modified alkylphenol resin is 40,000 to 60,000.

[0013] Optionally, in step (1), the molar ratio of octylphenol to formaldehyde solution is (0.7-0.8):1.

[0014] Optionally, the acidic catalyst is an HCl solution, and the amount added is 3-5% of the amount of octylphenol.

[0015] The alkaline catalyst is a NaOH solution, and the amount added is 5-8% of the amount of the first alkylphenol resin.

[0016] Optionally, in step (2), the molar ratio of petroleum resin to acrylic acid is (12-18):1.

[0017] Optionally, in step (2), the molar ratio of the second alkylphenol resin to the reaction product is (0.8-1.2):1.

[0018] Optionally, the antioxidant is antioxidant 3100 or antioxidant 6PPD;

[0019] The vulcanizing agent is sulfur, sulfur monochloride, or ethyl carbamate.

[0020] The accelerator is one or a mixture of two or more of the following: accelerator NS, accelerator DZ, and accelerator HMT.

[0021] According to another aspect of this application, a method for preparing a tire tread rubber composition as described in any of the preceding claims is provided, comprising the following steps:

[0022] S1. Premixing: Add the first rubber and the second rubber to the internal mixer, keep the roller in place, keep the roller in place, and mix again until the temperature reaches 160-170℃. Extrude the material to obtain the premixed rubber.

[0023] S2, First stage mixing: Add carbon black, modified alkylphenol resin, adhesive RA and premixed rubber to the internal mixer, keep it under pressure, keep it under lifting, and mix it under pressure again to 150-160℃, then extrude to obtain the first stage mixed rubber.

[0024] S3. Second stage mixing: Add the first stage compound, antioxidant, vulcanizing agent and accelerator to the internal mixer, press and hold, lift and hold, press and hold again, lift and hold again, and finally press and mix to 120-130℃, extrude and discharge to obtain the tire tread rubber composition.

[0025] Optionally, the pressure of the pressure roller is 0.4-0.8 MPa;

[0026] The rotor speed of the internal mixer is 15-55 r / min;

[0027] The holding time for the pressure point is 20-70 seconds, and the holding time for the teeto is 5-30 seconds.

[0028] Optionally, the processing interval between premixing and the first stage of mixing is 2-6 hours;

[0029] The processing interval between the first and second mixing stages is 4-8 hours.

[0030] The beneficial effects of this application include, but are not limited to:

[0031] 1. The tire tread rubber composition of this application, in which the first rubber and the second rubber work synergistically, can better balance the relationship between tire wear resistance, traction and rolling resistance, further improve tire service life and reduce raw material costs; the modified alkylphenol resin has a low free phenol content, which can reduce blooming phenomenon in the rubber compound during vulcanization, and has high bonding strength and good aging resistance; the interaction between the raw materials in the tread rubber composition of this application improves the viscoelasticity of the tire material and effectively improves tire durability.

[0032] 2. The tire tread rubber composition of this application, by adding modified alkylphenol resin, forms a resin protective layer between the steel cord and the rubber. This is caused by the polar migration of the modified alkylphenol resin in the rubber matrix. At the same time, more metal ion compound layers from the steel cord are also stacked here, causing factors that are beneficial to improving adhesion to accumulate here. The resin protective layer is embedded in the metal ion compound layer, which can bind the rubber and steel cord more firmly and enhance the adhesion between the two.

[0033] 3. In the preparation method of the tire tread rubber composition of this application, by optimizing the tread composition and content and improving the mixing process conditions and parameters, the tire adhesion strength and durability are improved while ensuring the tread's low rolling resistance, wet skid resistance and high wear resistance. This method can not only make full use of each raw material, but also has strong operability, high safety and is suitable for industrial promotion and application. Detailed Implementation

[0034] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0035] Unless otherwise specified in the examples, the procedures shall be performed under standard conditions or conditions recommended by the manufacturer. Raw materials or instruments whose manufacturers are not specified are all commercially available products.

[0036] Example 1

[0037] A method for preparing a tire tread rubber composition includes the following steps:

[0038] S1. Start premixing: Add 55 parts of natural rubber SPR10 and 65 parts of solution-polymerized styrene-butadiene rubber and isoprene rubber (weight ratio of 1:1) to an internal mixer (speed of 50 r / min). The pressure of the roller is 0.6 MPa. Hold the roller for 70 seconds and lift it for 30 seconds. Mix again until 162°C. Extrude the material to obtain the premixed rubber.

[0039] S2. After 4 hours, the first stage of mixing begins: 30 parts carbon black, 10 parts modified alkylphenol resin, 6 parts adhesive RA and the premixed rubber obtained in step S1 are added to an internal mixer (speed 55 r / min). The pressure of the roller is 0.6 MPa, the roller is held for 25 seconds, the roller is lifted for 5 seconds, and the mixture is mixed again at 155°C. The mixture is then extruded to obtain the first stage of mixed rubber.

[0040] S3. After 6 hours, the second stage of mixing begins: the first stage of compound obtained in step S2, 4 parts of antioxidant 3100, 2 parts of sulfur, and 1.2 parts of accelerator NS and accelerator DZ (the weight ratio of the two is 1:1) are added to the internal mixer (speed is 30 r / min). The pressure of the roller is 0.6 MPa. The roller is held for 40 seconds, lifted for 10 seconds, held for 50 seconds again, lifted for 15 seconds again, and finally mixed at 122°C. The mixture is then extruded to obtain the tire tread rubber composition.

[0041] The preparation method of modified alkylphenol resin includes the following steps:

[0042] (1) Dissolve octylphenol in toluene, and add 4% HCl solution and formaldehyde solution of octylphenol amount by amount in sequence. The molar ratio of octylphenol to formaldehyde solution is 0.75:1. Stir at 90℃ for 3h to obtain the first alkylphenol resin. Then add 7% NaOH solution of the first alkylphenol resin amount by amount and react the first alkylphenol resin with formaldehyde solution at 110℃ for 2h to obtain the second alkylphenol resin.

[0043] (2) Petroleum resin with a molar ratio of 15:1 and acrylic acid were reacted at 195°C for 2.5 h. Then, a second alkylphenol resin was added to the reaction product with a molar ratio of 1:1 to the reaction product. The reaction product was then subjected to a Diels-Alder addition reaction at 200°C to obtain a modified alkylphenol resin.

[0044] Example 2

[0045] A method for preparing a tire tread rubber composition includes the following steps:

[0046] S1. Start premixing: Add 45 parts of natural rubber SVR3L and 55 parts of isoprene rubber and brominated butyl rubber (weight ratio of 1:1) to a mixer (speed of 20 r / min). The pressure of the roller is 0.4 MPa. Hold the roller for 70 seconds and lift it for 30 seconds. Mix again until 160°C. Extrude the material to obtain the premixed rubber.

[0047] S2, 2 hours later, the first stage of mixing begins: 25 parts carbon black, 8 parts modified alkylphenol resin, 5 parts adhesive RA and the premixed rubber obtained in step S1 are added to an internal mixer (speed is 25 r / min). The pressure of the roller is 0.4 MPa, the roller is held for 25 seconds, the roller is lifted for 5 seconds, and the mixture is mixed again at 150°C. The mixture is then extruded to obtain the first stage of mixed rubber.

[0048] After S3 and 4 hours, the second stage of mixing begins: the first stage of compound obtained in step S2, 3 parts of antioxidant 6PPD, 1 part of urethane, and 0.5 parts of accelerator DZ and accelerator HMT (weight ratio of 1:1) are added to an internal mixer (speed of 15 r / min). The pressure of the roller is 0.4 MPa. The roller is held for 40 seconds, lifted for 10 seconds, held for 50 seconds again, lifted for 15 seconds again, and finally mixed at 120°C. The mixture is then extruded to obtain the tire tread rubber composition.

[0049] The preparation method of modified alkylphenol resin includes the following steps:

[0050] (1) Dissolve octylphenol in toluene, and add 3% HCl solution and formaldehyde solution of octylphenol amount by amount in sequence. The molar ratio of octylphenol to formaldehyde solution is 0.7:1. Stir at 80°C for 4 hours to obtain the first alkylphenol resin. Then add 5% NaOH solution of the first alkylphenol resin amount by amount and react the first alkylphenol resin with the formaldehyde solution at 100°C for 3 hours to obtain the second alkylphenol resin.

[0051] (2) Petroleum resin with a molar ratio of 12:1 and acrylic acid were reacted at 190°C for 3 hours. Then, a second alkylphenol resin was added to the reaction product with a molar ratio of 0.8:1 to the reaction product. The reaction product was then subjected to a Diels-Alder addition reaction at 180°C to obtain a modified alkylphenol resin.

[0052] Example 3

[0053] A method for preparing a tire tread rubber composition includes the following steps:

[0054] S1. Start premixing: Add 60 parts of natural rubber SPR10 and 75 parts of isoprene rubber to an internal mixer (speed is 45r / min). The pressure of the roller is 0.8MPa. Hold the roller for 70s and lift it for 30s. Mix again until 170℃. Extrude the material to obtain the premixed rubber.

[0055] S2. After 4 hours, the first stage of mixing begins: 35 parts carbon black, 12 parts modified alkylphenol resin, 8 parts adhesive RA and the premixed rubber obtained in step S1 are added to an internal mixer (speed 55 r / min). The pressure of the roller is 0.8 MPa, the roller is held for 25 seconds, the roller is lifted for 5 seconds, and the mixture is mixed again at 160°C. The mixture is then extruded to obtain the first stage of mixed rubber.

[0056] S3. After 6 hours, the second stage of mixing begins: the first stage of compound obtained in step S2, 5 parts of antioxidant 6PPD, 3 parts of sulfur monochloride and 2 parts of accelerator DZ are added to the internal mixer (speed is 25 r / min). The roller pressure is 0.8 MPa. The roller is held for 40 seconds, lifted for 10 seconds, then held for 50 seconds, lifted for 15 seconds, and finally mixed at 130°C. The mixture is then extruded to obtain the tire tread rubber composition.

[0057] The preparation method of modified alkylphenol resin includes the following steps:

[0058] (1) Dissolve octylphenol in toluene, and add 5% HCl solution and formaldehyde solution of octylphenol amount by amount in sequence. The molar ratio of octylphenol to formaldehyde solution is 0.8:1. Stir at 100℃ for 2 hours to obtain the first alkylphenol resin. Then add 8% NaOH solution of the first alkylphenol resin amount by amount and react the first alkylphenol resin with the formaldehyde solution at 120℃ for 1 hour to obtain the second alkylphenol resin.

[0059] (2) Petroleum resin with a molar ratio of 18:1 and acrylic acid were reacted at 200°C for 2 hours. Then, a second alkylphenol resin was added to the reaction product with a molar ratio of 1.2:1 to the reaction product. The reaction product was then subjected to a Diels-Alder addition reaction at 230°C to obtain a modified alkylphenol resin.

[0060] Comparative Example 1

[0061] The difference from Example 1 is that the modified alkylphenol resin is replaced with resorcinol-formaldehyde resin.

[0062] Comparative Example 2

[0063] The difference from Example 1 is that the solution-polymerized styrene-butadiene rubber and isoprene rubber in a weight ratio of 1:1 are replaced with cis-butadiene rubber.

[0064] Comparative Example 3

[0065] The difference from Example 1 is that the preparation method of the modified alkylphenol resin includes the following steps:

[0066] (1) Dissolve octylphenol in toluene, and add 4% sulfuric acid solution and formaldehyde solution in sequence, with the molar ratio of octylphenol to formaldehyde solution being 0.75:1. Stir at 90°C for 3 hours to obtain alkylphenol resin.

[0067] (2) Petroleum resin with a molar ratio of 15:1 and acrylic acid were reacted at 195°C for 2.5 h. Then, alkylphenol resin was added to the reaction product with a molar ratio of 1:1 to the reaction product. Diels-Alder addition reaction was carried out at 200°C to obtain modified alkylphenol resin.

[0068] Comparative Example 4

[0069] The difference from Example 1 is that a method for preparing a tire tread rubber composition includes the following steps:

[0070] S1. First stage premixing: Add 55 parts of natural rubber SPR10, 65 parts of solution-polymerized styrene-butadiene rubber, isoprene rubber (weight ratio of the two is 1:1), 30 parts of carbon black, 10 parts of modified alkylphenol resin, and 6 parts of adhesive RA to a mixer (speed is 50 r / min). The pressure of the roller is 0.6 MPa. The roller is held for 70 s and lifted for 30 s. The mixture is then pressed and mixed again at 162°C. The mixture is then extruded to obtain the first stage of compound.

[0071] S2. After 4 hours, the second stage of mixing begins: the first stage of compound obtained in step S1, 4 parts of antioxidant 3100, 2 parts of sulfur, and 1.2 parts of accelerator NS and accelerator DZ (weight ratio of 1:1) are added to an internal mixer (speed of 30 r / min). The roller pressure is 0.6 MPa. The roller is held for 40 seconds, lifted for 10 seconds, held for 50 seconds again, lifted for 15 seconds again, and finally mixed at 122°C. The mixture is then extruded to obtain the tire tread rubber composition.

[0072] Test case

[0073] Using 3+8×0.33HT steel cord as the matrix, the adhesion properties between it and the tread rubber compositions obtained in Examples 1-3 and Comparative Examples 1-4 were tested, and the results are shown in Table 1.

[0074] Table 1

[0075]

[0076] As can be seen from Table 1, the rubber composition prepared by the method of this application has stronger adhesion to steel cord and better tire aging resistance. Changing any of the following conditions, such as tread composition, content, mixing process conditions, and parameters, will affect the adhesion performance and durability of the tire.

[0077] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A tire tread rubber composition characterized by, By weight, it includes the following raw material components: 45-60 parts of primary rubber, 55-75 parts of secondary rubber, 25-35 parts of carbon black, 8-12 parts of modified alkylphenol resin, 5-8 parts of adhesive RA, 3-5 parts of antioxidant, 1-3 parts of vulcanizing agent, and 0.5-2 parts of accelerator. The first rubber is natural rubber SPR10 or natural rubber SVR3L, and the second rubber is one or two of solution-polymerized styrene-butadiene rubber, isoprene rubber, and brominated butyl rubber. The weight ratio of the first rubber to the second rubber is (0.8-1):

1. The preparation method of the modified alkylphenol resin includes the following steps: (1) Dissolve octylphenol in toluene, add acidic catalyst and formaldehyde solution in sequence, and stir at 80-100℃ for 2-4h to obtain the first alkylphenol resin. Then add alkaline catalyst and react the first alkylphenol resin with formaldehyde solution at 100-120℃ for 1-3h to obtain the second alkylphenol resin. (2) Petroleum resin and acrylic acid are reacted at 190-200℃ for 2-3 hours, and then a second alkylphenol resin is added to the obtained reaction product and a Diels-Alder addition reaction is carried out at 180-230℃ to obtain a modified alkylphenol resin.

2. The tire tread rubber composition according to claim 1, characterized in that, In step (1), the molar ratio of octylphenol to formaldehyde solution is (0.7-0.8):

1.

3. The tire tread rubber composition according to claim 1, characterized in that, The acidic catalyst is an HCl solution, and the amount added is 3-5% of the amount of octylphenol. The alkaline catalyst is a NaOH solution, and the amount added is 5-8% of the amount of the first alkylphenol resin.

4. The tire tread rubber composition according to claim 1, characterized in that, In step (2), the molar ratio of petroleum resin to acrylic acid is (12-18):

1.

5. The tire tread rubber composition according to claim 1, characterized in that, In step (2), the molar ratio of the second alkylphenol resin to the reaction product is (0.8-1.2):

1.

6. The tire tread rubber composition according to claim 1, characterized in that, The antioxidant is antioxidant 3100 or antioxidant 6PPD; The vulcanizing agent is sulfur, sulfur monochloride, or ethyl carbamate. The accelerator is one or a mixture of two or more of the following: accelerator NS, accelerator DZ, and accelerator HMT.

7. Process for the preparation of the tire tread rubber composition according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Premixing: Add the first rubber and the second rubber to the internal mixer, keep the roller in place, keep the roller in place, and mix again until the temperature reaches 160-170℃. Extrude the material to obtain the premixed rubber. S2, First stage mixing: Add carbon black, modified alkylphenol resin, adhesive RA and premixed rubber to the internal mixer, keep it under pressure, keep it under lifting, and mix it under pressure again to 150-160℃, then extrude to obtain the first stage mixed rubber. S3. Second stage mixing: Add the first stage compound, antioxidant, vulcanizing agent and accelerator to the internal mixer, press and hold, lift and hold, press and hold again, lift and hold again, and finally press and mix to 120-130℃, extrude and discharge to obtain the tire tread rubber composition.

8. The method of producing a tire tread rubber composition according to claim 7, characterized by, The pressure of the pressure roller is 0.4-0.8 MPa; The rotor speed of the internal mixer is 15-55 r / min; The holding time for the pressure point is 20-70 seconds, and the holding time for the teeto is 5-30 seconds.

9. The method of producing a tire tread rubber composition according to claim 7, characterized by, The processing interval between premixing and the first stage of mixing is 2-6 hours; The processing interval time between the first mixing and the second mixing is 4-8h.

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