FDA Food Grade Sealing Ring/NBR Rubber O-Ring Seal

Company Introduction:

Bomingyang Technology Co., Ltd. is located in Xi'an, Shaanxi Province, and is a technology-based enterprise integrating the research, production, and sales of rubber seals. The company mainly produces various rubber seals such as O-rings, X-rings, Y-rings, flat washers, V-rings, ED rings, C-rings, rubber strips, rubber balls, rubber retaining rings, and miscellaneous rubber parts.

O-rings (also known as O-ring seals, O-rings, or O-shaped rings) are ring-shaped mechanical gaskets made of elastic material with a circular cross-section. They are typically installed in a groove and compressed between two or more components during assembly to create a sealed interface. Due to their low cost, simple manufacturing, reliable functionality, and ease of installation, O-rings are commonly used in mechanical designs for sealing. They can withstand pressures of up to several tens of Pascals (kilopounds). O-rings can be used in static applications as well as in dynamic applications where there is relative movement between components, such as in rotary pump shafts and hydraulic cylinder pistons.

NBR rubber O-ring seals are primarily used in the manufacture of oil-resistant rubber products.

NBR rubber O-ring seals contain five different levels of acrylonitrile content (%). Higher acrylonitrile content improves oil resistance but reduces cold resistance. They can be used long-term in air at 120°C or in oil at 150°C. Additionally, they exhibit good water resistance, air tightness, and excellent bonding properties. They are widely used in the production of various oil-resistant rubber products, including oil-resistant gaskets, washers, sleeves, soft packaging, hoses, printing rollers, and cable materials, and serve as essential elastic materials in industries such as automotive, aviation, petroleum, and photocopying.

NBR rubber O-ring seals offer excellent oil resistance.

The typical structure of NBR contains approximately 78% trans configuration. Due to the presence of cyano groups in the molecular chain, NBR rubber O-ring seals exhibit superior oil resistance (e.g., to mineral oils, liquid fuels, animal and vegetable oils, and solvents) compared to natural rubber, chloroprene rubber, and styrene-butadiene rubber. NBR also has a broader operating temperature range than other rubbers, with a long-term service temperature of 120°C, and it maintains good low-temperature performance with a glass transition temperature as low as -55°C.

NBR rubber O-ring seals offer good chemical stability and processability. As the acrylonitrile content increases, the relative density rises, curing accelerates, tensile strength improves, but resilience decreases and cold resistance diminishes. Due to the polar nature of the cyano group, dielectric properties are reduced, making it a semiconductor rubber. NBR rubber O-ring seals can be classified into five categories based on acrylonitrile content: ultra-high, high, medium-high, medium, and low. Production methods include continuous and intermittent polymerization. Continuous polymerization is typically used for large-scale production with low consumption, while intermittent polymerization is suitable for small-batch, multi-variety production with higher engineering costs. Although NBR rubber has excellent physical and mechanical properties and processability, its performance in acidic gasoline and high-temperature (150°C) environments is inferior to that of fluoroelastomers and acrylic rubber. This has led to the development of high-performance HNBR rubber (HNBR). Additionally, NBR variants with extreme cold resistance, high purity, and carboxylated NBR (XNBR) have been developed.

NBR rubber O-ring seals are light brown elastomers with a molecular weight of approximately 700,000. Due to the strong polar cyano groups, they exhibit excellent stability against aliphatic hydrocarbon oils and gasoline.

ACN Classification:
High NBR rubber: ACN content 36%-42%
Medium-high NBR rubber: ACN content 31%-35%
Medium NBR rubber: ACN content 25%-30%
Low NBR rubber: ACN content below 24%

NBR rubber O-ring seals have good heat resistance, outperforming natural rubber and styrene-butadiene rubber. They can be used long-term at temperatures up to 100°C and at 120°C for 40 days.
① O-ring seals have poorer ozone resistance than CR but better than NR.
② Reinforcement provides O-ring seals with good physical mechanical properties and wear resistance.
③ When the acrylonitrile content of NBR rubber is 39%, its air tightness is comparable to IIR rubber, offering good sealing performance.
④ Low-temperature flexibility is moderate.
⑤ Excellent anti-static properties.
⑥ Polar ester plasticizers are effective for improving plasticity.
⑦ Good compatibility with polar materials such as PVC, alkyd resins, and nylon.
⑧ Low self-adhesion and high heat generation during mixing.

Excellent Oil Resistance;
NBR rubber O-ring seals are among the best general-purpose rubbers in terms of oil resistance, physical mechanical properties, and chemical resistance. Leveraging these characteristics allows them to meet various application needs. Among general rubbers, NBR far outperforms non-polar rubbers like NR, SBR, and IIR in resistance to benzene, petroleum-based oils, and non-polar solvents, and also exceeds the performance of polar CR. However, NBR's resistance to polar solvents and polar oils is not as strong.

After-Sales Service:

All company products come with material certifications. Sincerity wins trust, patience gains understanding; details determine success, service creates value. Service must be integrated throughout the entire enterprise, not limited to after-sales. Customized packaging and shipping methods are available based on customer requirements to meet different cleanliness standards. Whenever you need, I am ready to provide satisfactory products. If we have the honor of becoming your supplier, you can rest assured in terms of professionalism, quality, delivery, and service. Cooperating with us will make us a reliable and hassle-free supplier for you.