What is the role of various indicators of silica in the application? Introduction: The main component of white carbon black is SiO2, which is named because it is white, and its main physical properties and uses are similar to carbon black.

According to the different production methods, silica can be divided into precipitated silica (precipitated hydrated silica), gel method silica and fumed silica (fumed silica). The production methods of the three products are different. The properties and uses are also very different.

The products introduced below are produced by the sulfuric acid precipitation method, that is, the precipitation method silica, and the white carbon blacks involved in the following are all precipitation method white carbon blacks.

 The role of various indicators of silica in application

1. Specific surface area

The size of the reinforcing effect of silica mainly depends on its specific surface area. Generally, as the specific surface area increases, various strength indicators of rubber products increase, but the resilience decreases, the tear strength decreases, and it is not wear-resistant. It is difficult to disperse during refining, high heat generation, high Mooney viscosity, and easy to scorch. Therefore, different formulations and different uses require different specific surface areas, and the specific surface area has a different impact on the physical and mechanical properties of vulcanized rubber.

2. Oil absorption value

The oil absorption value reflects the degree of structure, the oil absorption value is large, the structure degree is small, the tensile strength of the vulcanizate is generally large, the tensile strength and hardness are large, especially the wear resistance is small, but the elongation rate is low. .

3, 900 ℃ burning loss

The performance is that when there are too many hydroxyl groups on the surface, it is easy to cause the structure of the rubber composite material and make the material brittle. It affects the processing performance, and the vulcanized rubber is easy to fall off, and the surface hydroxyl group has a strong adsorption effect on the vulcanization accelerator, which prolongs the vulcanization time.

4. Heating loss at 105℃

It reflects the amount of free water in the voids of the particles. When it is too small, it will be difficult for the rubber compound to have a high degree of structure. If the heating loss is zero, the silica is useless. Generally, it is more appropriate to control it at about 6%.

5. PH value

Generally around 7, the PH value increases (the acidity decreases), and the vulcanization speed of the rubber compound is accelerated. ,

6. Soluble salts

The less the better, but the less, the higher the cost.