Understanding Silicone Rubber

What is silicone rubber:

Definition: Silicone rubber is a type of polymer materials, its backbone consists of siloxane bonds (Si-O)

Importance: Rubber and plastics are two very important polymer materials that play a significant role in industry and daily life. Natural rubber and synthetic rubber are two main categories of rubber. Silicone rubber is a important branch of important branch of synthetic rubber. Therefore: Silicone rubber<Rubber

Key characteristics

1. High and Low-Temperature Resistance: Wide operating temperature range (-60°C to 250°C).
2. Weather Resistance: Excellent resistance to UV radiation and aging.
3. Electrical Insulation: Superior electrical insulation properties.
4. Biocompatibility: Suitable for medical and food-grade applications.
5. Chemical Stability: Resistant to acids, alkalis, solvents, and other chemicals.

Types of Silicone Rubber/By form and by processing

HCR/High Consistency Rubber/Solid Silicone: high-viscosity, gum-based silicone elastomer that requires curing to achieve its final properties. It is commonly processed through compression molding, transfer molding, or extrusion, followed by heat curing.

RTV Silicone/Room-Temperature Vulcanizing Silicone: RTV silicone is a liquid or paste-like silicone elastomer that cures at room temperature without requiring high heat. It is typically used for sealing, bonding, coating, and molding applications.

LSR/Liquid Silicone for injection molding: Liquid Silicone Rubber (LSR) is a two-part, platinum-cured silicone elastomer designed for high-precision injection molding. It offers excellent flowability, fast curing, and consistent mechanical properties, making it ideal for mass production of intricate silicone parts.

HTV (High-Temperature Vulcanizing) Silicone: is a high-consistency, heat-cured elastomer that requires high-temperature vulcanization to achieve its final properties. It is typically processed through compression molding, transfer molding, or extrusion, followed by heat curing using peroxide or platinum catalysts.

Conclusion: The definitions of silicone cross, such as one potting material, it can be a Liquid Silicone , and Room-Temperature Vulcanizing. And the other potting material, can be a Liquid Silicone, and High-Temperature Vulcanizing.

But silicone for injection molding, compression molding and extrusion is always HTV.

Silicone for casting(pouring), the definitions cross.

Factors to Consider When Choosing Silicone Rubber

Budget: Give the same technical index: tensile strength, tear strength. etc, LSR will cost more than solid silicone by weight. Besides the material cost, the tooling cost of liquid silicone (injection mold) is more expensive than that of solid silicone (compression mold)

Appearance: Liquid silicone offers better looking. Surface of LSR products is sensed more softer and smoother. And the spliter line(cause by two-plates mold) is less evident than solid silicone products.

Precision: Due to nature of low viscosity, automated processing, uniform mixing of liquid silicone, liquid silicone offers higher precision than solid silicone. Some high-value and high precision silicone products need to be achieved by liquid silicone injection molding.

Extrusion: Prevailing production is to extruded silicone using solid silicone. Liquid silicone takes less share in extrusion market.

Choosing Right Silicone Rubber Regarding the Application

Below is a base frame to help you choose your silicone rubber

Application	Silicone Rubber	Features	Our Model
Home	RTV for Casting	FDA certified	GA-88XX
	Food Grade Solid Silicone	FDA certified	GA-33XX
	Food Grade Liquid Silicone	FDA certified	GA-29XX
Automobile	Precipitated Solid Silicone	Long Product Life	GA-11XX
	Fumed Solid Silicone	Low VOC	GA-32XX
	Oil Bleeding Liquid Sicone	Low Friction	GA-20XX
	Flame Retardant Liquid Silicone	Resistant to fire	GA9600-XX
Electronics	Self Adhesive Liquid Silicone	Primerless & Low Defect Rate	GA-72XX
Medical	General Medical Solid Silicone	Pass ISO 10993	GA-TYXX
	General Medical Liquid Silicone	Pass ISO 10993	GA-65XX
	Medical Silicone for Implantation	Long time Implantation	No recommendation, recommended Newsil and Elkem branded
Optical	Typical RI 1.41	Regular High Tranparancy	CAS-35XX
	Higher RI 1.46 for Injection Molding	Higher RI for Injection Molding	CAS-TAXX
	RI 1.51 for high end LED encapsulation	Low viscosity for easy dispensing and molding	CAS-TDXX
Textile Coating	Liquid Silicone Coating for Glassfiber and Other Textile	Scratch-resistant, strong adhesion	GA-20X1
Silicone Foam	Liquid Foam Silicone	Flame-Retardant, Customzied Shape	GA-FXX