What is O-rings?

O-rings are annular sealing devices commonly used in various industries to prevent the passage of liquids, gases, or other contaminants between two surfaces. They are made from a flexible material, usually silicone or a synthetic elastomer such as nitrile, rubber, or Viton. The main function of the O-ring is to compress itself to achieve a tight sealing when the two surfaces are assembled.

Because of their simplicity, low cost, and high efficiency, O-rings are widely used in various applications such as automotive, aerospace, hydraulic systems, and chemical processing. They come in a variety of sizes, materials, and hardness levels to suit different environmental conditions and pressure requirements. Proper selection and installation of O-rings are essential to ensure the desired sealing performance and extend the service life of the component.

Types of Material Used to Construct O-rings

O-rings are used in applications that require resistance to pressure, temperature, and chemical exposure. To cater to these diverse requirements, O-rings are made from various materials. Here are some common materials used to construct O-rings:

Silicone (VMQ)

According to its vulcanization temperature, silicone rubber can be divided into two categories: high-temperature heating vulcanization type (HTV) and room-temperature vulcanization type (RTV). The high-temperature adhesive is mainly used for manufacturing all kinds of silicone rubber products, while room-temperature adhesive is mainly used as an adhesive, pot-sealing material, or mold.

Hot Vulcanized Silicone Rubber (HTV)
Hot vulcanized silicone rubber (HTV) is the most important kind of silicone product, and methyl vinyl silicone rubber (VMQ) is the most important kind of HTV, commonly known as high-temperature rubber. Methyl vinyl silicone rubber (raw rubber) is colorless, odorless, and non-toxic, with no mechanical impurities of the glue, raw rubber according to the demand to participate in the appropriate reinforcing agent, structural section preparation, curing agent and other additives mixed, and then temperature molding or extrusion molding, and then the second stage of vulcanization made of all kinds of products. Its finished products have excellent electrical insulation, arc resistance, corona, spark resistance, waterproof, moisture-proof, impact resistance, shock resistance, psychological inertia, permeability, and other functions.
Mainly used in aviation, instrumentation, electronic appliances, sailing, metallurgy, machinery, automobile, medical and health parts, can do all kinds of shapes of sealing rings, gaskets, tubes, and cables, but also can do human organs, blood vessels, breathable film, and rubber mold, fine forging release agent.
Room Temperature Vulcanized Silicone Rubber (RTV)
Room-temperature vulcanized silicone rubber is generally condensed and formed in two categories. Condensed room-temperature vulcanized silicone rubber is characterized by the condensation reaction between the silicon hydroxyl group and other active substances, which can be cross-linked into an elastomer at room temperature. The product is divided into single-component packaging and two-component packaging. Single component room temperature vulcanized silicone rubber (RTV-1 adhesive for short) is one of the first products of condensed liquid silicone rubber. It is made of foundation polymer, crosslinking agent, catalyst, filler, and additive. The product is packaged in a sealed hose, extruded when used, and can be vulcanized into an elastic body after contact with air, which is very convenient to use. Vulcanized rubber can be used in (-60 ~ +200℃) temperature limit for a long time, with excellent electric cut-off edge function and chemical invariance, water resistance, ozone resistance, weather aging resistance, a variety of metal and non-metal data has superior adhesion. Mainly used for coating all kinds of electronic components and electrical equipment, encapsulation data from insulation, moisture-proof, and shock-proof effect; As the appearance maintenance data of semiconductor devices; It can also be used as sealing interstitial material and elastic adhesive. Silicone O-rings are known for their flexibility and stability at extreme temperatures, both high and low. They also offer excellent resistance to UV light and ozone.

Nitrile Rubber (NBR)

What is nitrile rubber? Nitrile rubber also referred to as NBR, is a synthetic copolymer of acrylonitrile (ACN) and butadiene. This unsaturated copolymer is made up of 2-acrylonitrile and various butadiene monomers, offering a range of physical and chemical properties depending on the composition of nitrile in the polymer. 

Nitrile-Rubber-gasket

This material is widely used in the automotive and aerospace industries for oil and fuel handling hoses, seals, and rings due to its overall resistance to oil, fuels, and chemicals, as well as its ability to handle wide temperature ranges. Compared to natural rubber, NBR is less likely to cause adverse allergic reactions while providing superior strength and acid resistance although it is less pliable. While it is prone to ozone, ketones, esters, and aldehydes attack, it possesses remarkable resistance to aliphatic hydrocarbons. NBR is suitable for general-purpose applications and is known for its low cost and good mechanical properties.