With the product promotion of silicone sealant production process and the increasing market competition among companies, many manufacturers use white oil instead of dimethyl silicone oil as a plasticizer for silicone sealants in order to better control costs. Using a large amount of white oil instead of silicone oil in silicone sealants results in a significant reduction in many properties of silicone sealants, such as weather resistance, high and low temperature resistance, and the characteristics of super-performance silicone sealants. This greatly reduces the characteristics and service life of the original high-durability, super-performance silicone sealant. This type of white oil sealant is suitable for engineering projects. It has poor anti-aging properties and large shrinkage. It is very easy for the sealant to crack, become brittle and hard, which will affect the sealing performance and appearance of the curtain wall and even cause serious damage. engineering project accidents. Let's take a look at the role of silicone oil in silicone sealants.

The electrical properties of simethicone oil are good, especially the frequency factor is small in various frequency ranges. It has low interfacial tension and good shear resistance. According to the above good properties, simethicone is especially suitable for use as a plasticizer and diluent in silicone sealants.

In the use of silicone sealants, considering the needs of engineering construction, it is often necessary to adjust the viscosity of the sealant, reduce the viscosity of the adhesive, improve the fluidity of the engineering construction and the lubricity of the adherend, so dimethyl silicone oil is used etc. as plasticizers. At the same time, the addition of plasticizer can also improve the comprehensive performance of the cured adhesive layer, and improve the impact resistance and fatigue resistance of the bonded joint.

At the same time, the addition of plasticizers will also affect other properties of silicone sealants. Usually, with the expansion of the amount of plasticizer used, the tensile strength of silica gel will gradually decrease, and the elongation at break will gradually increase. The fundamental reason is not that the addition of reactive simethicone plasticizer reduces the number of connection points between polymer molecular chains, which leads to a decrease in cross-linking density, which ultimately leads to a decrease in tensile strength.

The reduction of the crosslink density reduces the rigidity of the three-dimensional structure, and the molecules are easy to slip, resulting in the expansion of the elongation at break. In addition, it is also seen that with the expansion of the amount of plasticizer used, the adhesive strength of silicone usually decreases. The fundamental reason is that the plasticizer is selected as a non-reactive plasticizer, which has a diluting effect on the active molecules of the silica gel, which will cause a decrease in the number of active groups in the unit volume.


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