High-Performance Silicone Gaskets: Key Features, Applications & Selection Guide

1. What is a Silicone Gasket?

A silicone sealing gasket is an elastic sealing component made from silicone rubber as the main raw material, processed through extrusion, vulcanization, and other techniques into strip- or band-shaped products. It is widely used in applications requiring sealing, waterproofing, shock absorption, and sound insulation, making it an indispensable part of many industrial and consumer products.

2. Core Features and Advantages

Silicone sealing strips are highly valued for their outstanding overall performance:

• Extremely Wide Temperature Range: Can remain elastic and functional long-term between -60℃ and 250℃, and withstand even higher temperatures for short periods. This far surpasses ordinary rubber, making it ideal for high-temperature ovens, automotive engine compartments, and refrigeration equipment.

• Excellent Weather Resistance and Aging Resistance: Outstanding resistance to UV, ozone, sunlight, rain, and snow. They do not easily crack, harden, or shrink, and have a very long service life, making them highly suitable for outdoor and automotive applications.

• Environmentally Friendly and Non-toxic: Silicone certified by FDA (U.S. Food and Drug Administration) and LFGB (EU food-grade standard) can be used in food and medical fields. It is odorless, non-toxic, and safe for human use.

• Good Physiological Inertness: Biocompatible, with some types certified to ISO 10993 medical-grade standards. They do not adhere to human tissue and can be used in medical devices.

• Outstanding Electrical Properties: High voltage resistance and high resistivity make silicone an ideal material for manufacturing high-voltage insulation equipment.

• Flexibility and Elasticity: Low compression set, meaning that even after long-term compression, the strip can return to its original shape, ensuring lasting sealing performance.

• Customizable Functional Properties: Through modification, silicone strips can also be made flame-retardant (UL94 V-0), conductive (for EMI shielding), thermally conductive, wear-resistant, and more.

3. Major Application Areas

Silicone sealing gaskets are used in almost every field:

• Automotive Industry: Door seals, window channels, engine compartment seals, battery pack seals (for new energy vehicles), headlamp seals, etc.

• Electronics & Appliances: Appliance door seals (ovens, refrigerators, dishwashers), waterproof seals for electronic devices (drones, smartphones), cable joint seals.

• Medical Devices: Breathing masks, medical catheters, analytical instrument seals, pharmaceutical equipment seals.

• Food Industry: Food processing equipment seals, water dispenser tubing, food container seals.

• Construction & Building Materials: Curtain wall joints, fireproof door and window seals, sunroom glass seals.

• New Energy: Photovoltaic module frame seals, energy storage cabinet seals.

4. Common Types and Forms

4.1 By Foam State

• Solid Silicone Strips: High density, strong sealing and compression resistance, good mechanical properties.

• Foamed Silicone Strips (sponge silicone strips): Low density, soft, excellent compressibility and resilience, superior soundproofing and shock absorption.

4.2 By Functional Properties

• Food-grade sealing strips, medical-grade sealing strips, flame-retardant strips, conductive strips, etc.

4.3 By Shape

• Round (O-rings), square, D-shape, P-shape, hollow, with lips, and complex custom profiles to fit different installation grooves and sealing needs.

(Illustration: Several common cross-sectional profiles of silicone sealing strips)

5. Brief Production Process

The main production steps are: Mixing → Extrusion → Vulcanization → Secondary Vulcanization → Inspection → Packaging.

• Extrusion: Mixed silicone material is extruded through molds into continuous strips.

• Vulcanization: Using hot air, microwave, or salt bath methods, silicone molecules crosslink and set to achieve final properties.

• Secondary Vulcanization: Further removes volatile substances, improving stability and environmental safety.

6. How to Choose the Right Silicone Sealing Strip?

When selecting, consider these key factors:

1. Application Scenario: Automotive, food, medical, or electronics? This determines required certification levels (e.g., FDA, UL).

2. Temperature Range: What are the maximum and minimum operating temperatures?

3. Contact Medium: Will it come into contact with oil, water, chemicals, or solvents? Choose material accordingly.

4. Performance Requirements: Is flame resistance, conductivity, thermal conductivity, or high tensile strength needed?

5. Size and Shape: Precisely measure installation groove dimensions and choose the matching profile to ensure effective sealing.

6. Environmental Requirements: Will the product be exported to the EU or North America? Compliance with RoHS, REACH, and other environmental directives may be necessary.

Summary

Silicone sealing strips are high-performance, widely applicable polymer sealing materials. Their unparalleled temperature resistance, excellent durability, and outstanding safety make them indispensable components in everything from household appliances to advanced industrial equipment. Selecting and applying the right silicone sealing strip can greatly enhance product reliability, safety, and service life.