Liquid Silicone Rubber (LSR) vs. High Consistency Silicone Rubber (HCR) in Medical Devices

LSR is a two-part, platinum-catalyzed silicone elastomer that cures into a non-toxic, flexible, and durable material. In liquid form, LSR is injected into molds to form complex shapes, with minimal material waste. It cures rapidly, has exceptional optical transparency and clarity, and is suitable for prolonged contact with the human body. It offers exceptional tear resistance, elongation, and chemical resistance.

LSR is commonly used in devices and components requiring tight tolerances and intricate geometries, including implantable pulse generators, defibrillators, spinal cord stimulators, brain stimulators, nerve stimulators, chemotherapy ports, pacemaker componentry, and optical lenses.

HCR, also known as solid silicone rubber, is a high-viscosity silicone elastomer that requires compression or extrusion molding to shape it into a desired form. It cures through a heat-activated process and is often used in devices requiring complex shapes or thin walls. Unlike LSR, it does not flow like a liquid but maintains its shape and can be manipulated into various forms using molding or extrusion processes.

HCR is known for its excellent mechanical properties, including high tensile strength, tear resistance, and compression set, making it suitable for applications that require durable and long-lasting performance. It is also known for maintaining its properties over a wide temperature range–from extreme cold to high heat–making it suitable for sterilization processes and harsh environmental conditions.

HCR is often used in devices that require durability, stability, resilience, and resistance to temperature variances, like O-rings, septa, seals, gaskets, surgical implants and components, compression pads and cushions, wound drains, drainage tubes, and respiratory masks.

While both Liquid Silicone Rubber (LSR) and High Consistency Silicone Rubber (HCR) are two types of silicone elastomers, they offer unique advantages. The choice between them depends on the specific requirements of the medical device and its application, as well as the performance and manufacturing process.

Flexan is a trusted manufacturing partner with more than 75 years of experience in supporting the world’s top medical device manufacturers with their growing device and component needs, including:

• Precision molding and extrusion processes
• Tip forming, bonding, and overmolding
• Tool design
• Design for Manufacturability (DFM)
• Expert material selection
• Mitigating patient risk
• Improving time to market

As your manufacturing partner, Flexan offers over 100,000 square feet of ISO-certified Class 7 and 8 Cleanroom space in five global locations. Contact us today or visit www.flexan.com to find out whether Flexan’s precision manufacturing solutions may be right for you.