阅读说明：本技术 一种低生热低成本轮胎橡胶组合物及其炼胶方法 (Low-heat-generation low-cost tire rubber composition and rubber mixing method thereof ) 是由 余本祎 史博 凌飞龙 于 2021-08-12 设计创作，主要内容包括：本发明公开了一种低生热低成本轮胎橡胶组合物,各原料的重量份数分别为：橡胶基体100份、炭黑-改性高岭土50份、硫磺粉1.5份、防护蜡1份、增塑剂A 3份、氧化锌3.5份、硬脂酸2份、防老剂RD 1.5份、硫化促进剂0.8份和防焦剂CTP 0.3份；其中,炭黑-改性高岭土中,炭黑与改性高岭土的重量比3～5:1。另外,本发明还提供该橡胶组合物的炼胶方法。本发明通过橡胶补强体系配方调整,在不降低产品性能前提下,可获得具有低生热特征的橡胶轮胎。(The invention discloses a low-heat-generation low-cost tire rubber composition, which comprises the following raw materials in parts by weight: 100 parts of a rubber matrix, 50 parts of carbon black-modified kaolin, 1.5 parts of sulfur powder, 1 part of protective wax, 3 parts of a plasticizer A, 3.5 parts of zinc oxide, 2 parts of stearic acid, 1.5 parts of an anti-aging agent RD, 0.8 part of a vulcanization accelerator and 0.3 part of a scorch retarder CTP; wherein in the carbon black-modified kaolin, the weight ratio of the carbon black to the modified kaolin is 3-5: 1. In addition, the invention also provides a rubber mixing method of the rubber composition. According to the invention, through the formula adjustment of the rubber reinforcing system, the rubber tire with the characteristic of low heat generation can be obtained on the premise of not reducing the product performance.)

1. A low-heat-generation low-cost tire rubber composition is characterized by comprising the following raw materials in parts by weight: 100 parts of a rubber matrix, 50 parts of carbon black-modified kaolin, 1.5 parts of sulfur powder, 1 part of protective wax, 3 parts of a plasticizer A, 3.5 parts of zinc oxide, 2 parts of stearic acid, 1.5 parts of an anti-aging agent RD, 0.8 part of a vulcanization accelerator and 0.3 part of a scorch retarder CTP; wherein in the carbon black-modified kaolin, the weight ratio of the carbon black to the modified kaolin is 3-5: 1.

2. The low heat generation and low cost tire rubber composition of claim 1, wherein the modified kaolin is modified by dry modification with a coupling agent or ball milling with a coupling agent.

3. The low-heat generation and low-cost tire rubber composition as claimed in claim 2, wherein the specific conditions for dry modification of the coupling agent are as follows: and dropwise adding a coupling agent into the kaolin, dispersing for 2-4 min in a high-speed dispersion machine with the rpm of more than 30000, and taking out for later use, wherein the dosage of the coupling agent is 2-6% of that of the kaolin.

4. The low heat generation and low cost tire rubber composition of claim 2, wherein the specific conditions for ball milling modification of the coupling agent are as follows: weighing kaolin and a coupling agent, placing the kaolin and the coupling agent in a ball milling tank, weighing 95% ethanol with 4 times of the dosage of the kaolin, pouring the ethanol into the ball milling tank, slightly shaking the mixture to preliminarily dissolve and mix the mixture, and finally placing alumina balls with 5 times of the dosage of the kaolin, wherein the ball milling speed is 40rpm/min, and the ball milling time is 5-7 hours; after the ball milling is finished, taking out a ball milling product, performing suction filtration and separation, washing the ball milling product for three times by using absolute ethyl alcohol with the dosage of 4 times of that of kaolin, and then putting the ball milling product into a vacuum drying oven to dry the ball milling product to constant weight at the temperature of 80 ℃; the dosage of the coupling agent is 2-4% of the concentration of the total solution.

5. The low heat generation and low cost tire rubber composition of claim 1, wherein the rubber matrix is selected from one or two of natural rubber, butadiene rubber, and solution polymerized styrene butadiene rubber.

6. A low heat generation, low cost tire rubber composition as in claim 1, wherein the carbon black is N234 or N660.

7. The low-heat-generation and low-cost tire rubber composition as claimed in claim 1, wherein the coupling agent used for modifying kaolin is one or a combination of gamma-aminopropyltriethoxysilane and chelating organoborate ester coupling agent, or other alkaline coupling agent.

8. A method for mixing rubber compositions for low heat generation and low cost tires as claimed in any one of claims 1 to 7, wherein the rubber matrix is plasticated in an open mill, and after coating the rollers, carbon black is added to produce a semi-finished rubber compound; sequentially adding zinc oxide, stearic acid, an anti-aging agent RD, a scorch retarder, protective wax and a plasticizer, plasticating until the materials are uniformly distributed, and then adding modified kaolin and sulfur; the cutting knife is placed at an angle of 45 degrees, and rubber tapping is carried out along the roller by the knife tip; performing thin-pass bubble removal on the rubber material by using a small roller spacing to obtain a smooth rubber sheet, and then beating a triangular bag for four times and rolling and compacting for four times to uniformly distribute the filler; and (3) increasing the roller spacing again, adjusting the proper thickness of the rubber material, taking out the rubber material, placing the rubber material on a table, standing for 8-72 hours, curing, and vulcanizing, wherein the vulcanization conditions are as follows: 151 ℃ for 40 min.

Technical Field

The invention relates to a low-heat-generation low-cost tire rubber composition and a rubber mixing method thereof, belonging to the technical field of rubber tire production.

Background

Rubber is a polymer with high elasticity, and usually needs to be reinforced and vulcanized to become a material with better service performance, such as rubber tires with the largest amount of rubber application market. Along with the development of the rubber tire industry, the carbon black industry also caters to the development concept of market 'green tires', and various types of carbon black such as high-structure carbon black, white carbon black, dual-phase carbon black and the like appear in succession, and one of the main purposes is to reduce the defect of high heat generation in the use process of the rubber tire by introducing new type of carbon black or reducing the using amount of the carbon black, and prolong the service life of the rubber tire.

From the upgrade analysis of the green tire industry in the future, the rubber tire is bound to accord with the development concepts of the 'double-carbon' background and the new energy electric vehicle industry, and the low rolling resistance, the high ground holding performance, the low carbon emission and the like are the development consensus of the tire industry, so that the new preparation process and the new formula of the rubber tire with high cost performance have important research and development values.

China is a big country of kaolin resources, but the kaolin has a small specific gravity when applied to the field of rubber, and only has the characteristic of reducing the cost in the traditional process, and the discussion of the kaolin on reducing the low rolling resistance of the rubber is continuously brought forward in recent years. For example, Wuming et al (Wuming, Yanfei, Li Xiao.) Kaolin wet modification and application thereof in tread rubber tire industry 2016, 36(12): 730-. However, compared with carbon black, the kaolin reinforced rubber has a weak interface bonding effect, and rubber molecular chains are easy to slip off under the action of external force, so that the tensile stress and tensile strength of the material are weak, which is also a modification and reinforcement direction that needs to be considered by many researchers in a rubber reinforcing system. The application of the synergistic effect of the nano kaolin, the carbon black and the white carbon black in the tires, the university of Chinese mining industry, 2016. the treated high-dispersion kaolin can effectively relieve clustered structures after agglomeration when being combined with the white carbon black or the carbon black, and promote dispersion of the nano kaolin and the carbon black, but the reactivity of the kaolin is still a certain difference from the high-dispersion kaolin and the white carbon black, and the plate-shaped structure of the kaolin in the tearing process ensures that the crack extending path is not as complicated as the carbon black or the white carbon black, and the tearing strength is reduced.

According to the analysis reported in the literature, kaolin and white carbon black are adopted to replace part of carbon black, a coupling agent is added to improve the binding capacity between the filler and the rubber matrix, and finally, the rubber product with high cost performance is obtained. Then, there is a few literature reports on how to select the coupling agent. Most fillers have active functional groups on the surface, such as kaolin, carbon black and the like, and the functional groups of surface hydroxyl and carboxyl are weakly acidic, so that the fillers are properly modified by selecting an alkaline coupling agent, and a good modification effect is easy to obtain.

Based on enterprise equipment and cost consideration, the invention provides a low-heat-generation and low-cost tire rubber composition and a rubber mixing method thereof on the premise of not increasing equipment, and a better bonding interface between kaolin and rubber is endowed by introducing a small amount of coupling agent. The introduction of the modified kaolin can not only reduce the binding sites of rubber and carbon black in a proper amount, but also enhance the mechanical property of rubber, and can greatly reduce the cost of rubber products.

Disclosure of Invention

The invention aims to provide a low-heat-generation and low-cost tire rubber composition and a rubber mixing method thereof, aiming at obtaining a rubber tire with low heat generation characteristic on the premise of not reducing the product performance by adjusting the formula of a rubber reinforcing system.

The purpose of the invention is realized by the following technical scheme:

a low-heat-generation low-cost tire rubber composition comprises the following raw materials in parts by weight: 100 parts of a rubber matrix, 50 parts of carbon black-modified kaolin, 1.5 parts of sulfur powder, 1 part of protective wax, 3 parts of a plasticizer A, 3.5 parts of zinc oxide, 2 parts of stearic acid, 1.5 parts of an anti-aging agent RD, 0.8 part of a vulcanization accelerator and 0.3 part of a scorch retarder CTP; wherein in the carbon black-modified kaolin, the weight ratio of the carbon black to the modified kaolin is 3-5: 1.

In the above, the modifying method of the modified kaolin adopts dry modification by a coupling agent or ball milling modification by a coupling agent.

In the above, the specific conditions for dry modification of the coupling agent are as follows: and dropwise adding a coupling agent into the kaolin, dispersing for 2-4 min in a high-speed dispersion machine with the rpm of more than 30000, and taking out for later use, wherein the dosage of the coupling agent is 2-6% of that of the kaolin.

The specific conditions for the ball milling modification of the coupling agent are as follows: weighing kaolin and a coupling agent, placing the kaolin and the coupling agent in a ball milling tank, weighing 95% ethanol with 4 times of the dosage of the kaolin, pouring the ethanol into the ball milling tank, slightly shaking the mixture to preliminarily dissolve and mix the mixture, and finally placing alumina balls with 5 times of the dosage of the kaolin, wherein the ball milling speed is 40rpm/min, and the ball milling time is 5-7 hours; after the ball milling is finished, taking out a ball milling product, performing suction filtration separation and washing with 4 times of anhydrous ethanol, and then putting the ball milling product into a vacuum drying oven to dry the ball milling product to constant weight at 80 ℃; the dosage of the coupling agent is 2-4% of the concentration of the total solution.

In the above, the rubber matrix is selected from one or two of natural rubber, butadiene rubber and solution polymerized styrene butadiene rubber.

In the invention, the coupling agent used for modifying the kaolin is one or a combination of two of gamma-aminopropyl triethoxysilane and chelating organic borate coupling agent, or other alkaline coupling agents. Generally, the mechanical property of rubber products can be improved by adopting the gamma-aminopropyltriethoxysilane and the alkaline silane coupling agent except the chelating organic borate coupling agent, and the combination of the kaolin and the rubber is improved under the action of the coupling agent, but the effect is not obvious. However, the inventor finds that when the gamma-aminopropyltriethoxysilane and the chelating organic borate coupling agent are combined in a ratio of 1:1, the obtained rubber product has obviously improved mechanical property, low rolling resistance and wear resistance compared with the single coupling agent. The gamma-aminopropyltriethoxysilane is compounded with chelating organic borate coupling agent to produce synergistic effect. Tests show that when the compound coupling agent is used, the low rolling resistance loss value of the rubber product is reduced by 30% compared with that of carbon black reinforced rubber, the tensile strength is improved by 10%, the elongation at break is improved by 20%, the cost is reduced by 10%, the synergistic effect of the compounding of the coupling agent is fully shown, and the effect is quite obvious.

In addition, the invention also provides a rubber mixing method of the rubber composition, which is characterized in that a rubber matrix is plasticated in an open mill, and after a roller is wrapped, carbon black is added to be uniformly fed to prepare a semi-finished rubber material; sequentially adding zinc oxide, stearic acid, an anti-aging agent RD, a scorch retarder, protective wax and a plasticizer, plasticating until the materials are uniformly distributed, and then adding modified kaolin and sulfur; the cutting knife is placed at an angle of 45 degrees, and rubber tapping is carried out along the roller by the knife tip; performing thin-pass bubble removal on the rubber material by using a small roller spacing to obtain a smooth rubber sheet, and then beating a triangular bag for four times and rolling and compacting for four times to uniformly distribute the filler; and (3) increasing the roller spacing again, adjusting the proper thickness of the rubber material, taking out the rubber material, placing the rubber material on a table, standing for 8-72 hours, curing, and vulcanizing, wherein the vulcanization conditions are as follows: 151 ℃ for 40 min.

The invention has the beneficial effects that: provides a carbon black-kaolin synergistic reinforced rubber combination system with low heat generation, high performance and low cost without large-scale production process or rubber tire formula adjustment. In particular, the performance of the rubber product is obviously enhanced by adopting the silane coupling agent and the chelating organic borate coupling agent to synergistically enhance compared with the effect of a single coupling agent.

Detailed Description

The following examples are further illustrative of the present invention and are not intended to limit the scope of the present invention.

Example 1:

75g of natural rubber and 25g of butadiene rubber are plasticated in an open mill, 41.65g of carbon black (N234), 1g of protective wax, 3g of plasticizer A, 3.5g of zinc oxide, 2g of stearic acid, 1.5g of antioxidant RD, 0.8g of vulcanization accelerator and 0.3g of anti-scorching agent are sequentially added after roller wrapping, and 8.35g of kaolin and 1.5g of sulfur are added after plastication is carried out to uniform distribution. The cutting knife is placed at an angle of 45 degrees, and rubber tapping is carried out along the roller by the knife tip; performing thin-pass bubble removal on the rubber material by using a small roller spacing to obtain a smooth rubber sheet, and then beating a triangular bag for four times and rolling and compacting for four times to uniformly distribute the filler; and (3) increasing the roller spacing again, adjusting the proper thickness of the sizing material, taking out, placing on a table, standing for 12 hours, curing, wherein the vulcanization conditions are as follows: 151 ℃ for 40 min.

Example 2:

0.344g of gamma-aminopropyltriethoxysilane is added dropwise to 8.35g of kaolin, dispersed in a high-speed dispersion machine at 34000rpm/min for 2min and then taken out for standby.

75g of natural rubber and 25g of butadiene rubber are plasticated in an open mill, 41.65g of carbon black (N234), 1g of protective wax, 3g of plasticizer A, 3.5g of zinc oxide, 2g of stearic acid, 1.5g of antioxidant RD, 0.8g of vulcanization accelerator and 0.3g of anti-scorching agent are sequentially added after roller wrapping, and after uniform distribution, 1.5g of modified kaolin and sulfur described in example 2 are added. The cutting knife is placed at an angle of 45 degrees, and rubber tapping is carried out along the roller by the knife tip; performing thin-pass bubble removal on the rubber material by using a small roller spacing to obtain a smooth rubber sheet, and then beating a triangular bag for four times and rolling and compacting for four times to uniformly distribute the filler; and (3) increasing the roller spacing again, adjusting the proper thickness of the sizing material, taking out, placing on a table, standing for 12 hours, curing, wherein the vulcanization conditions are as follows: 151 ℃ for 40 min.

Example 3. gamma. -aminopropyltriethoxysilane was used in an amount of 0.5g, and the remaining steps and procedure were the same as in example 2.

Example 4. gamma. -aminopropyltriethoxysilane 0.25g and chelating organoborate coupling agent 0.25g, the remaining steps and procedures were the same as in example 2.

Example 5

Preparing modified kaolin: weighing 8.35g of kaolin and 1.16g of gamma-aminopropyltriethoxysilane, placing the kaolin and the gamma-aminopropyltriethoxysilane in a ball milling tank, weighing 33.4g of 95% ethanol, pouring the 95% ethanol of the kaolin into the ball milling tank, slightly shaking to primarily dissolve and mix the kaolin, the coupling agent and the ethanol, finally placing alumina balls with 5 times of the kaolin, and carrying out ball milling for 7 hours at the ball milling speed of 40 rpm/min. After the ball milling is finished, taking out the ball-milled modified kaolin solution for centrifugal separation, washing the ball-milled modified kaolin solution for three times by using 33.4g of absolute ethyl alcohol, then putting the ball-milled modified kaolin solution into a vacuum drying oven, drying the ball-milled modified kaolin solution at the temperature of 80 ℃ until the weight is constant, and taking out the ball-milled modified kaolin solution for later use.

The rubber mixing process was the same as in example 2.

Example 6

Preparing modified kaolin: weighing 8.35g of kaolin, 0.86g of gamma-aminopropyltriethoxysilane and 0.86g of chelating organic borate coupling agent, placing the materials in a ball milling tank, weighing 33.4g of 95% ethanol, pouring the 95% ethanol of the kaolin into the ball milling tank, slightly shaking to preliminarily dissolve and mix the kaolin, the coupling agent and the ethanol, finally placing 5 times of kaolin-used alumina pellets, and carrying out ball milling for 7 hours at the ball milling speed of 40 rpm/min. After the ball milling is finished, taking out the ball-milled modified kaolin solution for centrifugal separation, washing the ball-milled modified kaolin solution for three times by using 33.4g of absolute ethyl alcohol, then putting the ball-milled modified kaolin solution into a vacuum drying oven, drying the ball-milled modified kaolin solution at the temperature of 80 ℃ until the weight is constant, and taking out the ball-milled modified kaolin solution for later use. The rubber mixing process was the same as in example 2.

Table 1 gives the basic formulations of examples 1-6 and blank 1.

Table 1 formulations of examples 1-6 and blank 1

Note: in examples 5 and 6, the number of the coupling agent was the amount of the coupling agent grafted on the surface of kaolin.

Table 2 shows the mechanical properties such as vulcanization rate index, degree of crosslinking, elongation at break, tensile strength, etc. of examples 1-6 and blank 1.

TABLE 2 associated Performance data for examples 1-6 and blank 1

As can be seen from table 2, example 1 is a resin without the addition of a coupling agent, carbon black: the performance data for kaolin =5:1 shows that the addition of kaolin reduces the rate of vulcanization, the degree of crosslinking, the 100% proof stress and the 300% proof stress, but increases both the tensile strength and the elongation at break. This is mainly due to the fact that kaolin has less abundant surface functional groups than carbon black, and has less bound gum content than carbon black,

example 2 is that gamma-aminopropyltriethoxysilane with 4% kaolin content is added, the vulcanization speed is accelerated, but the cross-linking degree tensile strength and the stress at definite elongation are superior to those of example 1, but the mechanical property reduction caused by partial replacement of carbon black by kaolin cannot be avoided, but the loss factor of the product at 60 ℃ is obviously reduced, which indicates that the introduction of the coupling agent improves the bonding condition between kaolin and rubber to a certain extent, and the specific expression is that the mechanical property is increased compared with that of example 1.

Example 3 was the addition of 6% kaolin amount of gamma-aminopropyltriethoxysilane, which resulted in faster cure, slightly lower cross-linking, tensile strength, elongation at break, but increased stress at elongation at break, yet still lower than 100% carbon black reinforced blank 1, and a loss factor at 60 ℃ inferior to that of example 2.

Example 4 in order to adjust the composition of the coupling agent based on example 2, 2% kaolin amount of gamma-aminopropyltriethoxysilane and 2% kaolin amount of chelating organic borate coupling agent were used. The data of the embodiment shows that the coupling agent composition is superior to blank sample 1 in all data, the mechanical property is greatly improved, the loss factor at 60 ℃ is obviously reduced, and the synergistic enhancement and the heat generation value reduction effects among the coupling agent compositions are shown.

Example 5 is the mechanical property data for a rubber article using ball-milled modified kaolin with a coupling agent amount of 2.7% in solution. From example 5, it can be seen that the ball-milled modified kaolin undergoes ball milling for 7 hours, the particle size is obviously reduced, the rubber is obviously reinforced, and the loss factor at 60 ℃ can be reduced.

Example 6 references the ball-milled modified kaolin clay after example 4 for reinforcement of rubber articles. From example 6, it can also be seen that the synergistic effect of the silane coupling agent and the chelating organoborate coupling agent after combined use is particularly a loss factor ratio which is a factor of greatly decreasing the loss factor at 60 ℃ by about 30%.

Table 3 relevant performance test data for examples 7-9 and blank 2

The invention also provides the reinforcement difference of different carbon black varieties to rubber. The formula adjustment and cost reduction in the actual production process of enterprises have certain reference value. Example 7/8/9 differs in that the carbon black: kaolin: the coupling agents (gamma-aminopropyltriethoxysilane) were 3:1:0.04, 3:1:0.06, 2:1:0.06, respectively.

Table 4 relevant performance test data for examples 7-9 and blank 2.

As can be seen from blank 2 of table 4, soft N660 has a reduced reinforcing effect on rubber compared to hard N234. When the modified kaolin replaces part of N660 carbon black, the change range of other mechanical properties is not large except that the vulcanization speed and the crosslinking density are obviously reduced, the formula not only can greatly reduce the product cost, but also does not obviously reduce various properties of the product, and the formula is suitable for reducing the product cost.