How to improve the aging resistance of silica gel and the service life of the product?

Silicone, as a widely used polymer material in various fields, is highly favored due to its excellent temperature resistance, weather resistance, electrical insulation, and biocompatibility. However, when exposed to natural environments or specific working conditions for a long time, silicone also faces aging problems, manifested as increased hardness, decreased toughness, surface cracking, and even complete loss of performance. Therefore, it is of great significance to improve the aging resistance of silica gel and extend its service life to ensure product quality and reduce maintenance costs.

1、 Analysis of aging mechanism of silicone gel

The aging of silicone mainly comes from the following factors:

1. Thermal oxygen aging: High temperature and oxygen are the two main culprits that accelerate the aging of silicone gel. Under high temperature, the chemical bonds in silicone molecular chains are prone to breakage, leading to a decrease in material properties.
2. Photoaging: Ultraviolet radiation can damage the molecular structure of silicone surface, trigger photochemical reactions, and accelerate the material aging process.
3. Damp heat aging: The combined effect of moisture and high temperature can promote the internal hydrolysis reaction of silicone gel, leading to the deterioration of material properties.
4. Chemical erosion: Certain chemical substances, such as acids, bases, solvents, etc., can react with silica gel, causing structural damage.
5. Mechanical stress: Continuous mechanical stress can cause fatigue fracture of silicone molecular chains and accelerate aging.

2、 Strategies for improving the aging resistance of silica gel

1. Formula optimization
Adding antioxidants: By adding an appropriate amount of antioxidants to the silicone formula, free radicals can be effectively captured, the oxidation reaction rate can be slowed down, and the thermal oxidative stability of silicone can be improved.
Using light stabilizers: Adding UV absorbers or light shielding agents can effectively absorb or reflect UV rays, protecting silicone from the effects of photoaging.
Adjusting crosslinking density: Increasing the crosslinking density of silicone appropriately can improve its moisture and heat resistance and mechanical strength, but attention should be paid to avoiding excessive crosslinking that may cause material brittleness.
2. Raw material selection
Selecting high-quality base polymers: The quality of base polymers directly affects the performance and aging rate of silicone gel. The selection of basic polymers with high purity, low volatility and good stability is the basis for improving the aging resistance of silica gel.
Selection and surface treatment of fillers: Suitable fillers can not only reduce costs, but also slow down the aging process through physical barriers. Surface treatment of fillers, such as coupling agent treatment, can enhance the interfacial bonding between fillers and matrix, and improve overall performance.
3. Processing technology control
Temperature control: During the processing of silicone, strictly control the heating temperature and cooling rate to avoid prolonged exposure to high temperatures and reduce the risk of thermal oxidative aging.
Optimization of molding process: Adopting reasonable molding processes such as injection molding, extrusion molding, etc., to ensure uniform stress distribution inside silicone products and reduce aging acceleration caused by stress concentration.
Post treatment process: such as heat treatment, aging pretreatment, etc., can further stabilize the structure of silica gel and improve its aging resistance.
4. Surface treatment and coating
Surface coating: apply a protective layer with anti-aging performance on the surface of silicone products, such as silicone coating, polyurethane coating, etc., which can effectively isolate the direct erosion of silicone by external environmental factors.
Plasma treatment: the surface of silica gel is modified by plasma technology, which can enhance the hydrophobicity, wear resistance and anti-aging property of the surface.

3、 Methods to extend the service life of silicone products

1. Optimizing the usage environment
Avoid extreme environments: Try to avoid prolonged exposure of silicone products to high temperatures, strong ultraviolet radiation, high humidity, or corrosive environments.
Regular maintenance and inspection: Regularly inspect silicone products to promptly detect and address potential signs of aging, such as cracks, discoloration, etc.
2. Design optimization
Structural design: Reasonable structural design can reduce the mechanical stress experienced by silicone products during use and extend their service life.
Material selection matching: Select suitable silicone materials based on the application scenario, such as high-temperature resistant silicone, oil resistant silicone, etc., to ensure that the material performance meets the usage requirements.
3. User education and usage guidance
Provide user manual: Provide users with detailed usage and maintenance manuals to guide them in correctly installing, using, and maintaining silicone products.
Emphasize precautions: Emphasize avoiding improper operations such as excessive stretching, twisting, impact, etc. to reduce aging acceleration caused by human factors.

4、 Case analysis

Take the automobile sealing strip as an example. As an important part of the automobile, the aging resistance and service life of the silicone sealing strip are directly related to the sealing performance and driving safety of the automobile. By adopting high-purity basic polymers, adding special antioxidants and light stabilizers, optimizing the molding process and surface coating treatment and other measures, an auto parts enterprise has successfully improved the aging resistance of silicone sealing strips, enabling them to maintain excellent sealing performance and durability in harsh environments such as high temperature, high humidity, strong ultraviolet light, etc., greatly extending the service life of products, and winning high recognition in the market.