Application of silica in tire industry
Silica is an important reinforcing raw material in the rubber industry, and is also used in pesticides, feed, toothpaste and coatings. With the increasingly stringent requirements of environmental protection and energy saving in human society, the demand for radial tires that can reduce rolling resistance and save fuel and "green tires" with lower rolling resistance is developing rapidly. Therefore, the consumption and product variety of silica in the tire industry are also developing rapidly.

First, the application of silica in tires
In the tire industry, silica was mainly used in the belt layer of radial tires in the past to enhance the adhesion between steel wire and rubber. Some tire companies also use it for the tread of heavy-duty radial tires to improve the puncture resistance and collapse resistance of the tread. The dosage is small, generally 10 to 15 parts. In the past ten years, due to the increasingly strict requirements for environmental protection and energy saving in Europe and North America, the use of silica in tire treads can significantly reduce the rolling resistance of tires, while maintaining good ice-skid resistance and wet-skid resistance. properties, and its wear is only slightly reduced. In 1992, Michelin Company first launched the "green tire" reinforced with silica, its rolling resistance is reduced by about 30% compared with ordinary tires, and the effect of saving fuel and reducing automobile exhaust gas is remarkable. In addition, silica is also used in the tread compound of winter (snow) tires and high-performance tires. However, in foreign countries, the price of silica is equivalent to 140% of carbon black. In addition, the cost of adding coupling agent and rubber compound processing increases significantly, and the cost of tires increases significantly, and the antistatic performance of tires using silica alone is not good. . Therefore, in the production of tires with low rolling resistance, the combination of carbon black and silica is often used to achieve the best performance/cost effect.

At present, the amount of silica in the domestic tire industry is not much. It is mainly used in the tread compound of all-steel radial truck tires. Generally, 12 to 15 parts of silica are used. In the tread compound of semi-steel radial tires or light truck tires, silica is generally not used except for some foreign tire companies producing original tires for high- and mid-range cars.

In foreign countries, silica is mainly used in the manufacture of car "green tires" and winter tires. It has also begun to be applied in heavy-duty "green tires", all-weather tires and construction machinery tires. This article will focus on the application in the manufacture of "green tires".

People have three basic requirements for tires. One is to have higher grip (anti-slip) on wet roads or better traction to ensure the safety of vehicles and personnel; the other is to have low rolling resistance to save fuel and reduce exhaust emissions. General tire rolling resistance is reduced by 3% to 4%, the fuel consumption can be reduced by 1%. The rolling resistance based on the tread is about 50% of the car tire and 30% of the heavy duty tire, so reducing the rolling resistance of the tread is an important way to save fuel. The influence of various parts of the car and truck tires on the rolling resistance is shown in Figure 1; the third is good wear resistance and long service life. In order to obtain the above properties, the application of silica, especially high-dispersity silica, in tread rubber is essential.

In foreign countries, silica is currently mainly used in the tread of radial car tires. Among them, the tires with more use have lower rolling resistance and are called "green" tires, followed by the tread of radial truck tires to improve the tread. The puncture resistance and chipping resistance are excellent, and the dosage is less, generally 10 to 15 parts. As can be seen from Figure 1, in order to further reduce the rolling resistance of the tire, in addition to increasing the amount of silica in the tread compound, silica should also be used in other parts of the tire.