Food grade seal [Rubber]

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Silicone rubber o-rings are common food-grade O-rings. The physical and chemical properties of silicone rubber: The material of silica gel is a saturated non-polar rubber formed by silicon atoms obtained from quartz with side chains such as methyl and vinyl. Different side chains will cause silicone rubber to have different characteristics. Methyl vinyl silicone rubber (VMQ) is a kind of silicone rubber O-ring silicone O-ring material that is widely used. Food-grade silicone o-rings have excellent heat resistance, low-temperature elasticity and particularly excellent resistance to oxidation and ozone, as well as high air permeability and selectivity for gas transmission. Good electrical insulation properties (volume resistance greater than 1016 ohm.cm, breakdown voltage above 30kv/mm), corona resistance and arc resistance. However, by adding conductive carbon black, nickel powder, aluminum powder, and silver powder, proper conductivity can be obtained (volume resistance can reach 5-0.02 ohm.cm). Silicone rubber is hygroscopic and can play a role in isolation. Water resistance, but poor resistance to water vapor, pressure over 50psi is not recommended. Compatible with most oils, chemicals and solvents. Generally, silicone rubber has good resistance to acids and alkalis, acceptable to polar solvents, and not resistant to alkane hydrogen and aromatic oils. It is not recommended to use in most concentrated solvents, oils, concentrated acids, and diluted caustic soda solutions. Special silicone rubber also has properties such as radiation resistance, flame resistance and oil resistance. It has low tensile strength and weak wear resistance, and is generally not used for dynamic sealing.
Molecular structure of silicone rubber:
CH3 CH=CH
—(Si—O)(Si—O) methyl vinyl silicone rubber O-ring
CH3 CH3
Other materials O-shaped rubber sealing ring:
1. Food-grade NBR nitrile rubber O-ring: suitable for use in petroleum hydraulic oil, glycol hydraulic oil, diester lubricating oil, gasoline, water, silicone grease, silicone oil and other media. It is a rubber seal with wide application and low cost. Not suitable for polar solvents, such as ketones, ozone, nitro hydrocarbons, MEK. The general operating temperature range is -40~120 ℃. Heat resistance, cold resistance, oil resistance, water tightness, abrasion resistance, chemical resistance, deformation resistance, mechanical properties, strong tension, 10 years.
2. Food-grade HNBR hydrogenated nitrile rubber O-ring: It has excellent corrosion resistance, tear resistance and compression deformation resistance, and has good resistance to ozone, sunlight and weather. It has better abrasion resistance than nitrile rubber. It is suitable for washing machinery, automobile engine system and refrigeration system using new environmentally friendly refrigerant R134a. It is not recommended to use in alcohols, esters or aromatic solutions. The general use temperature range is -40~150 ℃.
3. Food-grade SIL silicone rubber O-ring seal: It has excellent heat resistance, cold resistance, ozone resistance and atmospheric aging resistance. Has good insulation properties. However, the tensile strength is worse than that of general rubber and has no oil resistance. Suitable for household appliances such as electric water heaters, electric irons, microwave ovens, etc. It is also suitable for all kinds of articles that are in contact with the human body, such as kettles, drinking fountains, etc. It is not recommended to use in most concentrated solvents, oils, concentrated acids and sodium hydroxide. The general use temperature range is -55~250 ℃. Environmental protection, ozone resistance, weather resistance, heat resistance, cold resistance, chemical resistance, oil resistance, abrasion resistance, deformation resistance, 30 years.
4. Food-grade VITON fluorine rubber O-shaped sealing ring: The high temperature resistance is better than that of silicone rubber, and it has excellent weather resistance, ozone resistance and chemical resistance, but poor cold resistance. It is resistant to most oils and solvents, especially acids, aliphatic hydrocarbons, aromatic hydrocarbons and animal and vegetable oils. It is suitable for the sealing requirements of diesel engines, fuel systems and chemical plants. Not recommended for use in ketones, low molecular weight esters and nitrate-containing mixtures. The general temperature range is -20~250 ℃. Ozone resistance, weather resistance, water tightness, abrasion resistance, flame resistance, strong tension, heat resistance, cold resistance, chemical resistance, oil resistance, abrasion resistance, deformation resistance, 30 years.
5. Food-grade FLS fluorosilicone rubber O-type sealing ring: Its performance has the advantages of fluorocarbon rubber and silicone rubber, and it has good oil resistance, solvent resistance, fuel oil resistance and high and low temperature resistance. It can resist the corrosion of oxygen-containing compounds, aromatic hydrocarbon-containing solvents and chlorine-containing solvents. Generally used for aviation, aerospace and military purposes. It is not recommended to expose to ketones and brake fluid. The general temperature range is -50~200 ℃.