Applications of silicone sealant

Silicone sealant, as a high-performance material based on siloxane polymers, boasts excellent weather resistance, temperature resistance (both high and low), electrical insulation properties, and flexibility. It has become an indispensable bonding and sealing solution in numerous industries. 

Its unique molecular structure gives it a service life of over 25 years, and it can withstand extreme temperature conditions ranging from -60℃ to 250℃. It plays a crucial role in various fields such as global construction, electronics, healthcare, and automobiles. 

01 Construction Field
Silicone sealant is the most widely used in the construction industry. Different types of silicone sealants each undertake their own specialized tasks. 

Silicone structural sealant is the "framework" of the curtain wall project. It is mainly used for the structural bonding between the glass and the aluminum secondary frame in concealed glass curtain walls or semi-concealed glass curtain walls. 

It needs to endure various stresses such as wind loads, self-weight, temperature changes for a long time, and at the same time resist environmental aging caused by ultraviolet rays, ozone, and moisture. The designed service life should be no less than 25 years. 

Silicone weatherproof sealant acts as the "outer layer" of the building, responsible for sealing various joints of the curtain walls, ensuring the water and air tightness of the structure. 

This type of adhesive needs to withstand changes in the width of the joint and aging caused by outdoor conditions. Its key indicators are high elasticity and resistance to aging. 

The special silicone sealant for roof skylights is designed for transparent and semi-transparent materials with high thermal expansion coefficients commonly found in building skylights. It can generate very low tensile and compressive stresses during the thermal expansion and contraction of the materials, preventing them from being pulled apart, thereby providing a long-lasting waterproof sealing effect. 

Special-purpose silicone sealants include fireproof sealants and mold-resistant sealants, etc. Fireproof sealants are used for fireproof sealing at each layer of curtain wall projects, as well as for fireproof sealing of various doors and windows. Mold-resistant sealants are commonly used for the installation of kitchen utensils and sanitary fixtures, as well as for waterproof and mold-resistant sealing. 

02 Industrial Manufacturing Field
In industrial production, silicone sealant demonstrates great flexibility in application. Industrial silicone sealant is mainly used in the industrial manufacturing field, such as mold manufacturing and plywood production. 

This type of silicone adhesive has excellent tensile, tear resistance and compression resistance properties, which can meet the requirements for material strength and durability in industrial manufacturing. 

The automotive powertrain sealant, such as LOCTITE® SI 5999 produced by Henkel, is a gray, thixotropic, de肟 type silicone paste-like sealant. It is used for the planar sealing design, maintenance, manufacturing and reconstruction of the automotive powertrain. 

It is non-corrosive and explosion-proof, and can dry on the surface within a few minutes. It is suitable for the demanding working environment of automotive power systems. 

The vehicle body repair sealant, such as TEROSON® SI 9140, is a one-component silicone sealant product used for emergency repairs of vehicles, such as sealing of joints and leakage points. 

It has a rapid eye-skin bonding time (5-7 minutes), excellent UV resistance, and can provide good adhesion for painted metals and bare metals, glass, and fully cured automotive paints. 

03 Electronic and Electrical Industry
The electronic and electrical industry has extremely strict requirements for silicone sealants. And silicone sealants have shone brightly in this field due to their unique electrical properties. 

Electronic silicone sealant is mainly used for sealing and protecting electronic products, such as the encapsulation of electronic components, the fixation and insulation of circuit boards, etc. 

It possesses excellent high-temperature resistance, chemical corrosion resistance and electrical insulation properties, which can effectively protect electronic products from the influence of the external environment. 

The adhesive silicone for fixing appliances is suitable for power supplies, electronic appliances, household appliances, air filters, electric ovens, microwave ovens, and other products. 

This type of silicone adhesive features a single-component formula, high strength, and rapid curing. It has excellent resistance to temperature extremes, a firm adhesive layer, outstanding electrical insulation properties, resistance to ultraviolet rays, resistance to electrical arcs and corona discharges, and resistance to impact. 

Outdoor electronic device sealants such as 599W electronic adhesive are single-component neutral silicone sealants, featuring excellent bonding, fixation and sealing capabilities. 

It has a bonding and sealing effect on small household appliances such as lamps, underwater instruments and equipment, microwave ovens, electric irons, electric heaters, and household appliance control boards. It can be used outdoors for a long time within the temperature range of -60℃ to 230℃. 

04 Medical and Cosmetic Field
In the medical and cosmetic fields, the application of silicone gel directly affects human health and appearance, and it places extremely high demands on its biocompatibility and stability. 

Medical silicone gel is mainly used in medical devices and their auxiliary products, such as breast implants, soft tissue filling materials, and catheters. 

Medical silicone gel has excellent biocompatibility and stability, and can be used in the human body for a long time without causing foreign body reactions. It also has good flexibility and shape stability. 

Medical silicone pressure-sensitive adhesive is applied in the transdermal controlled-release drug system, serving as the controlled-release adhesion layer of the nitroglycerin film. Through drug dissolution tests, pharmacological experiments, and clinical verification, it has been proven to be feasible. 

The cosmetic silicone gel is mainly used for injection filling and plastic surgery. It can be applied for nose augmentation, chin augmentation, filling of nasolabial folds, and filling of facial depressions, etc. 

The cosmetic silicone gel has excellent plasticity and stability. After injection, it can maintain the filling effect for a long time, and at the same time, it can also meet the flexible adjustment needs of cosmetic doctors for the shape. 

Silicone gel dressings have a significant clinical effect in preventing and treating hypertrophic scars. Studies have shown that silicone gel dressings are effective in treating hypertrophic scars and have no significant difference in long-term prognosis compared to self-adhesive silicone gels. 

05 Special Application Scenarios
Apart from the common fields mentioned above, silicone sealant also plays a crucial role in some special scenarios. The low modulus and high elongation silicone sealant performs exceptionally well in waterproofing of concrete joints. 

After curing, the Shore hardness of this sealant is approximately 10, the 100% tensile modulus is about 0.21 MPa, the elongation rate is 1250%, and it has a strong adhesion to concrete, with a displacement capacity of 50 grades. 

It is mainly used for sealing the joints (flexible joints) of concrete buildings such as roads, bridges, airports, flood control and waterproof dams, municipal squares, and sports venues. It has a long-lasting waterproof and sealing effect. 

High-strength industrial repair silicone sealant can be used for structural bonding and sealing in fields such as engineering vehicles, rail locomotives, automobiles, and construction machinery. 

This type of adhesive usually has higher bonding strength and durability, and can withstand more demanding mechanical stress and environmental conditions. 

The table below summarizes the main performance requirements of silicone sealant in various application fields: 

Application fields    Primary performance requirements    Special considerations
Construction field    Weather resistance, elasticity, durability    Displacement capacity, UV resistance
Electronic and electrical    Electrical insulation, temperature resistance    Low toxicity, corrosion resistance
Automotive industry    Resistant to oil, temperature, vibration    Adhesion to various substrates
Medical and cosmetic    Biocompatibility, stability    Long-term implant safety
With the advancement of materials science, silicone sealants are evolving towards higher performance, more environmental friendliness and more specialized directions. In the future, we may witness self-repairing silicone sealants, biodegradable silicone sealants, and special silicone sealants for extreme environments (such as space, deep sea). 

The application boundaries of this technology will continue to expand with the advancement of technology, and it will remain an indispensable role in human life and industrial manufacturing. 

This response is generated by AI and is provided for reference only. Please verify it carefully.