The specific gravity (density) of liquid injection silicone is affected by many factors. The following is a detailed explanation of these influencing factors:
1. The influence of raw materials
Silicone composition:
Liquid injection silicone is mainly composed of base polymer, filler, cross-linking agent, catalyst, etc. Among them, the type and content of the base polymer will directly affect the specific gravity of the silicone. Different types of polymers have different densities. Therefore, the choice of base polymer in the formula will significantly affect the specific gravity of the silicone.
Filler addition:
Fillers are commonly used additives in liquid injection silicone to adjust the properties of silicone, such as hardness, strength, wear resistance, etc. The type and amount of fillers added will directly affect the specific gravity of silicone. For example, adding high-density fillers (such as white carbon black) will increase the specific gravity of silicone, while adding low-density fillers (such as hollow glass microspheres) will reduce the specific gravity of silicone.
2. The influence of production process
Mixing process:
Mixing is a key step in the production process of liquid injection silicone. During the mixing process, the mixing uniformity of raw materials and temperature control will affect the specific gravity of silicone. If the mixing is not uniform, it may cause density differences inside the silicone, thus affecting its overall specific gravity.
Vulcanization conditions:
Vulcanization is an important part of the liquid injection silicone molding process. Vulcanization conditions (such as temperature, time, pressure, etc.) will affect the crosslinking density and internal structure of the silicone, thereby indirectly affecting its specific gravity. For example, increasing the vulcanization temperature or extending the vulcanization time may increase the crosslinking density of the silicone, thereby increasing its specific gravity.
3. The influence of other factors
Temperature:
Temperature is one of the important factors affecting the specific gravity of liquid injection silicone. As the temperature increases, the thermal motion of the silicone molecules intensifies, and the distance between molecules increases, which may cause the specific gravity of the silicone to decrease. However, during the vulcanization process, as the temperature increases, the crosslinking density of the silicone increases, which may increase its specific gravity. Therefore, the effect of temperature on the specific gravity of silicone is complex and needs to be considered comprehensively.
Pressure:
During the molding process of liquid injection silicone, the injection pressure affects the fluidity and filling of the silicone in the mold. Although the pressure itself does not directly change the specific gravity of the silicone, it indirectly affects its specific gravity by affecting the molding quality and internal structure of the silicone. For example, insufficient injection pressure may cause bubbles or defects inside the silicone, thereby reducing its specific gravity.
Humidity:
Humidity has little effect on the specific gravity of liquid injection silicone, but it still needs to be considered in some specific cases. For example, silicone stored in a humid environment may absorb moisture, resulting in an increase in specific gravity. However, this change is usually small, and the original specific gravity of the silicone can be restored by drying.
In summary, the specific gravity of liquid injection silicone is affected by raw materials, production process and many other factors. In practical applications, it is necessary to select appropriate raw materials and production processes according to specific needs and conditions to obtain liquid injection silicone products with ideal specific gravity.