Characteristics and Applications of Silicone Sealing Rings

Silicone sealing rings are a type of sealing ring made from various silicone materials，which are used to secure annular covers, ensuring they fit within the gap between bearing rings or washers, preventing moisture or oil leakage.

Currently, they are primarily used for waterproof sealing and preservation in everyday items such as food containers, rice cookers, water dispensers, lunch boxes, insulated boxes, fresh-keeping containers, water cups, ovens, magnetized cups, and coffee pots. They are convenient, safe, and environmentally friendly, making them popular.

Today, let's learn about silicone sealing rings.

First, let's understand what silicone is.

Silicone is a highly active adsorbent material, an amorphous substance, and a type of rubber with the chemical formula mSiO₂nH₂O.

It is insoluble in water and all solvents, non-toxic and odorless, chemically stable, and unreactive with all substances except strong alkalis and hydrofluoric acid. Due to its unique properties, wide temperature resistance, and excellent chemical resistance, it is also referred to as a specialty rubber, along with fluororubber. Therefore, silicone is widely used in various seals to meet various sealing requirements in our machinery and daily lives.

So, what are the advantages of silicone seals compared to seals made of other materials?

1. Wide Temperature Resistance

(1). Heat resistance: Silicone seals offer significantly better heat resistance than ordinary rubber. They can withstand high temperatures without deformation or the production of harmful substances.

They can withstand nearly indefinite use at 150°C without performance degradation, can withstand continuous use for 10,000 hours at 200°C, and can even withstand use at 350°C for a period. They are widely used in applications requiring heat resistance, such as thermos seals.

(2).Cold Resistance: While ordinary rubber has a low temperature limit of -20°C to -30°C, silicone rubber maintains excellent elasticity at temperatures between -60°C and -70°C. Certain specially formulated silicone rubbers can even withstand extremely low temperatures, such as low-temperature seals, which can reach temperatures as low as 100°C.

2. Excellent Insulation

Silicone rubber has excellent electrical insulation properties, as well as excellent corona resistance (resistance to quality degradation) and arc resistance (resistance to deterioration caused by high-voltage arcs).

3. Hygroscopicity

Silicone rubber rings have a low surface energy, absorbing moisture from the environment and providing insulation.

4. Excellent Weather Resistance

Weather resistance refers to a series of aging phenomena caused by exposure to external conditions such as direct sunlight, temperature fluctuations, wind and rain, including fading, discoloration, cracking, chalking, and loss of strength. Ultraviolet radiation is the primary factor contributing to product aging.

The SI-O-S-I bond in silicone rubber is extremely stable to oxygen, ozone, and ultraviolet light, offering excellent resistance to ozone and oxidizing agents. Without any additives, it exhibits excellent weather resistance, resisting cracking even after prolonged outdoor use. Silicone rubber seals are generally believed to last for over 20 years outdoors.

5. Safe and Environmentally Friendly Materials

Silicone rubber has unique physiological properties: it is non-toxic, tasteless, and odorless, offering excellent freshness preservation. It is also less susceptible to external environmental influences and resists yellowing or fading over long-term use.

6. High Air Permeability and Gas Permeability

After reading about the advantages of silicone rubber seals, you might be curious about their drawbacks. So, what are the disadvantages of silicone seals?

1. Poor mechanical properties in terms of tensile strength and tear resistance

2. Poor water vapor resistance. They are not recommended for use at pressures exceeding 50 psi.

3. Silicone rubber has little resistance to alkanes, hydrogen, and aromatic oils. Silicone seals are not recommended for use in most concentrated solvents, oils, concentrated acids, and diluted caustic soda solutions.

4. They are relatively expensive compared to other silicone rubber products.

The above is an introduction to the performance characteristics of silicone seals. Silamine seals are made of food-grade silicone material, characterized by resistance to deformation and aging under extreme temperatures.

Due to their superior reliability, longevity, extreme temperature suitability, and stability, they are widely used and play a vital role in our daily lives, bringing us many conveniences.