What are the crosslinkers and catalysts for liquid silicone rubber?
Crosslinkers and Catalysts for Liquid Silicone Rubber are Key Components for the Curing Process
1. Crosslinkers
Crosslinkers in liquid silicone rubber (LSR) play a critical role in linking polymer chains to form a three-dimensional network structure, enhancing the material's strength and stability. Common crosslinkers used in LSR include:
Methylhydrosiloxane:
This is a widely used crosslinker that reacts with vinyl-containing polysiloxanes under the action of a catalyst to form a stable crosslinked structure.
2. Catalysts
Catalysts accelerate the crosslinking reaction in LSR, reducing curing time and increasing production efficiency. Different catalysts significantly impact the curing rate and the properties of the cured LSR. Common LSR catalysts include:
Platinum Catalysts:
Platinum catalysts are the most commonly used in addition-cure LSR. They exhibit high catalytic activity, enabling rapid curing at room or low temperatures. Platinum catalysts are highly compatible with methylhydrosiloxane and vinyl-containing polysiloxanes, ensuring a smooth crosslinking reaction.
Alcohol-Modified Chloroplatinic Acid Catalysts:
These catalysts allow for extended working time at ambient temperatures and rapid curing upon heating. They are suitable for LSR products requiring prolonged working time and quick curing.
Additionally, other catalysts, such as bis(alkyne)-bis(triphenylphosphine) platinum complexes and bis(alkyne)(cyclodiene) platinum complexes, are also available, each with unique advantages and specific application scopes.
3. Summary
Crosslinkers and catalysts are essential components in the curing process of liquid silicone rubber. Crosslinkers link polymer chains to form a three-dimensional network, enhancing material strength and stability, while catalysts accelerate the crosslinking reaction, reducing curing time and improving production efficiency.
Selecting the appropriate crosslinker and catalyst is critical for producing high-performance LSR products. Practical applications require choosing suitable components based on specific performance requirements and application scenarios.