◆Two-component LSR VS one-component LSR
Two-component liquid silicone rubber and one-component liquid silicone rubber exhibit significant differences in several aspects, including curing mechanisms, composition, shelf life, performance characteristics, and application areas. Below is a detailed comparison:
1. Curing Mechanism
Two-Component Liquid Silicone Rubber: This type consists of two components, A and B, which must be mixed in a specific ratio before use. The mixture then cures through a chemical reaction, either at room temperature or with the application of heat to accelerate the reaction rate.
One-Component Liquid Silicone Rubber: This type does not require additional curing agents or catalysts. It contains latent curing agents pre-mixed into its formulation. When exposed to moisture in the air or trace amounts of water, it gradually cures from the surface inward at room temperature to form an elastomer.
2. Composition
Two-Component Liquid Silicone Rubber: Composed of a base polymer, crosslinking agent, catalyst, fillers, and other components. The A and B components contain different reactive ingredients that chemically react upon mixing to achieve curing.
One-Component Liquid Silicone Rubber: Also contains a base polymer, catalyst, fillers, and other components, but all ingredients are pre-mixed. The addition of a latent curing agent allows it to cure spontaneously when exposed to moisture.
3. Shelf Life
Two-Component Liquid Silicone Rubber: The two components remain stable and separate until mixed, which gives them a longer shelf life, often lasting several years without curing. However, prolonged storage may reduce fluidity, requiring re-stirring before use.
One-Component Liquid Silicone Rubber: Since it is in a latent curing state within its packaging, its shelf life is relatively shorter. Generally, the shelf life is up to about one year, and poorly packaged products may only last around six months.
4. Performance Characteristics
Two-Component Liquid Silicone Rubber: Typically offers high transparency, excellent weather resistance, temperature resistance, tensile strength, and high dielectric constant and insulation properties. The cured product usually has a relatively soft or gel-like consistency.
One-Component Liquid Silicone Rubber: Offers excellent aging resistance, moisture resistance, electrical insulation, and arc resistance. Additionally, it features superior flame retardancy, good fluidity, short surface drying time, and strong adhesion to most metal and non-metal materials.
5. Application Areas
Two-Component Liquid Silicone Rubber: Due to its outstanding performance, it is widely used for encapsulating and protecting optical components such as LEDs and displays; coating and potting precision electronic components and PCBs; manufacturing optical silicone rubber devices like Fresnel lenses and silicone nose pads; and in coatings for materials like glass and silicone rubber-based paints.
One-Component Liquid Silicone Rubber: This type is commonly used for coating, sealing, and bonding various electronic components and electrical equipment. It serves multiple functions, including bonding, insulation, moisture resistance, shock absorption, and positioning.