O-ring NBR 70 & 90
Oring NBR 70 and 90 are types of o-rings. Orings are circular-shaped gaskets made of an elastomer material placed between two metal surfaces. The o-ring gives a tight connection as it serves as a sealant to ensure no escape of gas or liquid materials during the operation of the hydraulic system.
There are different types of materials used in the production of an o-ring such as Viton o-ring, Neoprene o-rings, silicon o-rings, ethylene-propylene rubber (EPR), Nitrile (Buna-N) o-ring, etc. Nitrile (Buna-N) o-ring is specially designed to withstand temperatures between -30⁰C to 120⁰C. NBR 70 is also referred to as Acrylonitrile Butadiene Copolymer and the most used elastomer material in the industry while NBR 90 is a harder version of the NBR material.
1. What is NBR ?
NBR is an acronym for the term Nitrile Butadiene Rubber. This rubber material is derived from butadiene and acrylonitrile (ACN). It is known under trade names such as Europene, Krynac, Nipol, etc. The elastomer material has a great resistance for oil, chemicals, fuels, etc. also, NBR material can withstand pressure ranging between -30⁰C to 120⁰C and applicable in a variety of industries. Aside from this, the rubber material is used in the production of other rubber materials such as sponges, footwear, sealants, mats, etc.
The table below shows the material properties of NBR:
The resistance of the rubber varies and depends largely on the amount of polymer contained. But, an NBR material with a high amount of polymer will contain high oil resistance, less flexibility, and vice versa.
One major advantage of the NBR material is its resistance to many oils and acids, unlike the natural rubber material. NBR has a tensile strength ≥ 10 MPa (10N/mm²). NBR is the most used rubber material due to these superb features and qualities. Also, it possesses high tensile strength and resistance against abrasion. One drawback of the material is the low flexibility level. However, NBR material exceeds other natural rubbers in a highway.
2. What is NBR 70 ?
NBR 70 is also known as Acrylonitrile Butadiene Copolymer. The compound has a medium acrylonitrile content and suitable for temperatures ranging between -40 ⁰C to 135 ⁰C, also it can be customized to fit the temperature range between -55 ⁰C to 135 ⁰C. NBR 70 is also widely used in the industry and suitable for various applications such as aircraft, automotive, military, fuel systems, etc. NBR 70 also has a high resistance to oil, petroleum products, abrasion, and other chemicals.
The material is also referred to as black NBR. The only drawback of the NBR material also affects this NBR 70 material. NBR materials cannot withstand harsh weather and ozone. Although the NBR 70 material is faced with these problems, however, it still offers excellent services and productivity when used in the manufacturing of other tools.
The table below shows the composition of NBR 70:
3. What is NBR 90 ?
NBR 90 is a nitrile compound formulated with a medium percentage of acrylonitrile. When compared to NBR 70, NBR 90 is a harder rubber in texture. NBR 90 is suitable for applications working with higher pressures and temperatures. NBR 90 is applied in various industries and comes in black color. NBR 90 works with a temperature ranging between -30° to +120°C.
4. What are the advantages of NBR o-rings ?
NBR O-rings are one of the commonly used materials in the industry. Aside from being used for o-rings, NBR is also used in the hydraulic industry for seals, pipe and cable covers, and gaskets.
NBR material gives the finished products (o-ring) some superb features which are explained below:
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High level of resistance against oils, acids, fats, hydrocarbons, and suitable to be applied in a wide variety of industries.
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High level of resistance against heat.
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Very durable and possess strong mechanical features.
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Highly reliable and provides a good seal for metal surfaces during operation.
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Cheaper than other elastomer materials
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Able to withstand working in water.
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Excellent resistance against abrasion and other harsh chemicals.
Please refer to the chemical resistance application below: