Main classification of new carbon black varieties for tires

The new carbon black varieties for tires mainly include low rolling resistance carbon black and high performance carbon black.

Low rolling resistance carbon black reduces tire rolling resistance, and the development of "green tires" is an inevitable trend in the development of today's tire products.

Cars bring great convenience to human life, and the car consumes a lot of oil and generates a lot of waste gas, which also brings huge pollution to human beings. Therefore, low rolling resistance tires, or "green tires" and "environmentally friendly tires", which are capable of further fuel saving on the basis of ensuring tire wear resistance and traction, are rapidly developed. The rolling resistance of tires has been listed in the European Union and the United States as the basis for the quality classification and fuel consumption limits of tires. China has also formulated and begun to implement national standards for automobile fuel consumption limits, so it is imperative to reduce tire rolling resistance.

The three factors affecting the fuel consumption of the car are the air resistance of the car body, the rolling resistance of the tire and the resistance of the engine power transmission. At a speed of 100 km per hour, the rolling resistance of the tire is three times the power transmission resistance, and the air resistance of the car body is 1 /2, that is, the rolling resistance of the tire accounts for more than 1/3 of the driving resistance of the car. Practice has shown that when the rolling resistance of a car tire is reduced by 7.3% or the rolling resistance of a truck tire is reduced by 3.6%, the fuel consumption of the automobile can be reduced by about 1%.

There are the following ways to reduce the rolling resistance of tires: the tubeless and ultra-flattening of radial tires; the use of solution-polymerized styrene-butadiene rubber; the use of highly dispersible white carbon black or low rolling resistance carbon black; the miniaturization and weight reduction of tires.

The rolling resistance of the tire comes from the rubber lag loss caused by the rolling deformation when the tire is running, the friction between the tire and the road surface, and the air resistance of the tire itself. Unless the road surface is particularly bad or the driving speed is too fast, the rubber compound hysteresis loss due to rolling deformation under normal conditions is a major factor affecting the rolling resistance of the tire.

While reducing the rolling resistance of the tire, it is necessary to take into account the comprehensive performance of the tire, so that the tire maintains good driving safety, that is, wet skid resistance, ice slip resistance or collective traction, and must be used for a long time. Life, ie wear resistance, puncture resistance and cutting, etc.

Among them, wear resistance is the main factor determining the service life.

Rubber is a typical viscoelastic material. When it is under alternating stress and strain, hysteresis and mechanical loss occur. Its dynamic modulus consists of two parts, namely elastic modulus and loss modulus. Loss modulus is used for To overcome the viscous drag, the ratio of loss modulus to elastic modulus is called loss factor or loss tangent (tan£) or "internal consumption". The larger the loss factor, the greater the heat build-up of the compound.

Studies have shown that when the tread rubber is at 20~0 °C, the tan £ is larger (that is, the low temperature rolling resistance is larger), the wet skid resistance is better; and at 50 to 70 ° C, the tan £ is smaller ( That is, when the tire is running at the tread temperature, the rolling resistance is small.

The traditional tread rubber carbon black varieties, when the particle size is small, the rubber has good wear resistance and wet skid resistance, and the hysteresis of the rubber compound is that the rolling resistance increases. When the particle size is large, the rubber has good elasticity, low heat generation, and reduced rolling resistance, but the wet skid resistance and wear resistance are decreased. The precipitated hydrated silica has similar reinforcing properties to carbon black, so it is also called white carbon black. White carbon black can make the tan£ and temperature of the tread rubber have a good correlation, that is, the tan£ is higher when the temperature is lower, the tan£ is lower when the temperature is lower, and the higher physical property can be imparted to the rubber compound. Mechanical behavior.伹 is due to the strong interaction between the silica particles, the silica is difficult to disperse, and the Mooney viscosity of the silica composite is large, the tensile stress is limited, and the mixing process is difficult. For this reason, until the emergence of new sulfur-containing silane coupling agents such as si69, France's Michelin was the first to produce "green tires" with low rolling resistance, good overall performance, and all-purpose white carbon black. Branded luxury car package. In order to solve the problem of poor dispersion of white carbon black, an easy-to-process bismuth-dispersible white carbon black has appeared. The rolling resistance of the silane-coupled silica tire in the tread rubber can be reduced by 30% compared with the conventional carbon black type, and the wet skid resistance is basically unchanged, but the abrasion resistance is reduced by about 7%. However, due to the white carbon black The mixing process is still more complicated than carbon black, requires more expensive coupling agents, has poor antistatic properties, and high price of silica itself. At present, white carbon black and carbon black are still used in combination. It has been reported that the use of 35 parts of silica and 25 parts of carbon black in the tread rubber formulation can reduce the rolling resistance by 18%, while the wet skid resistance and abrasion resistance maintain the level of all-purpose carbon black. In the tread rubber, white carbon black is mainly used in Western Europe. In 2006, the global high-dispersion white carbon black consumption was about 150,000 tons, and it continued to increase.

In order to meet the demand for carbon black in low rolling resistance tires, it is also to compete with "white carbon black". Several foreign carbon black manufacturers start from improving carbon black structure, widening the distribution of carbon black aggregates and increasing the surface activity of carbon black. We have developed a low rolling resistance carbon black series that can adapt to different types of tires of different specifications. Cabot has also developed a carbon black-silica black dual phase filler, or a series of "duplex carbon black". The low rolling resistance carbon black can be further classified into the following types.