The Difference Between VMQ, FVMQ, FKM, FFKM

VMQ, FVMQ, FKM, FFKM Definition 

1. VMQ/ Silicone: the main chain of silicone is composed of silicon atoms and oxygen atoms alternately. It is a kind of polymer elastic material with both inorganic and organic properties. Because of its chemical composition and physical structure, silicone has the following advantages in application.

（1）Stable chemical properties, insoluble in any other solvents and solutions except hydrofluoric acid (HF) and strong alkali;

（2）Good thermal stability, the working temperature is from -40 to 230℃.

（3）Silicone has rigid skeleton structure, good wear resistance and compressive strength. 

Notes: The biggest difference between silicone and fluororubber: silicone is not resistant to oil, and fluororubber is products that made after the second vulcanization with oil resistant.

There was 1 type of silicone keypad which was custom made by our customers before, they choose  common silicone to make keypad, while they didn’t let us know the working conditions of the keypad, so after shipped the samples to them for confirm, they found all keypad inflating when encounter with oil, we suggest them to change the material to FVMQ, then problem solved.

2. FVMQ/ Fluorsilicone: in addition to the general characteristics of silicone rubber, there are excellent resistance to aviation fuel oil, hydraulic oil, oil, chemical reagent and solvent performance. Able to work at -55 ~ +200℃ for a long time.

3. FKM/ Fluororubber: It is a synthetic polymer elastomer containing fluorine atoms on the carbon atoms of the main or side chains. With the introduction of fluorine atom, rubber is endowed with excellent heat resistance, oxidation resistance, oil resistance, corrosion resistance and atmospheric aging resistance. It has been widely used in the fields of aerospace, aviation, automobile, petroleum and household appliances, and is a key material that cannot be replaced in the advanced national defense industry.

FKM-Material Report- XMN18-007129-01.PDF

FKM-Material Report-F70101CA.pdf

FKM-Material ReportF70202C.pdf

4. FFKM/ Perfluoroether rubber: Poor machining performance, generally the hardness is over 70 Shore A. It is used in the occasions where fluorine rubber is not competent and has harsh conditions. In addition to excellent chemical and heat resistance, the product is homogeneous, without penetration, cracking and pinhole on the surface.These features can improve the sealing performance, extend the operation cycle and effectively reduce the maintenance cost. It an be used for making products that resistant to all kinds of media, such as rocket fuel, umbilical, oxidant, nitrous oxide, fuming nitric acid and other seals, used in aerospace, aviation, chemical industry, petroleum, nuclear energy and other industrial sectors.

VMQ, FVMQ, FKM, FFKM Application 

1. Silicone/ VMQ: Silicone has been widely used in daily life. accoridng to the grade, we can devided it into 3 types: common silicone, FDA Food Grade Silicone, FDA Medical Grade Silicone.

FDA Medical Grade Silicone is a widely used biological material in cosmetic surgery. Medical grade silicone has good biocompatibility, no irritation, no toxicity, no allergic reaction to human tissues, and few rejection reactions.It has good physical and chemical properties, and can maintain its original elasticity and softness in contact with body fluids and tissues, without being degraded. It is a kind of relatively stable inert material.It can withstand high temperature and disinfect.Easy to shape, easy to carve shape, easy to use. Mainly used for making silicone umbrella valve, silicone duckbill valve, silicone gasket, silicone seal, silicone mask cushion, nasal pillows, etc.

FDA Food Grade Silicone is widely used in coffee pot, water heater, toaster, sterilizing cabinet, water dispenser, kettle, scaler, rice cooker, fryer, fruit pulp machine, burner and other mechanical products, mechanical, electrical, electrical and other industries.Such as: water dispenser, silicone dispensing valve, silicone sleeve, silicone one way valve, coffee pot, hairdressing equipment and lighting products protective cover;Fireproof silicone tube: it has the characteristics of fire resistance, high pressure resistance, high temperature resistance and environmental protection.It is mainly used in food mould, chocolate mould, candy mould, precision casting, carbon fiber composite material, food cake mould, process ceramics, printing, human organ cloning, household appliances, lighting products, silicone ice box, Silicone Baby Nipple, etc.

2. Fluorsilicone: FVMQ fluorsilicone o-ring keeps the excellent properties of silicone materials such as heat resistance, cold resistance, high voltage resistance, weather aging resistance, etc. Due to the introduction of fluorine containing groups, it also has excellent hydrogen-resistant solvents, oil resistance, acid and alkali resistance and lower surface energy performance of organic fluorine materials, it can be used for produce FVMQ Seal, FVMQ Gasket, FVMQ Keypad, FVMQ O-ring,etc.

Primary uses of fluorosilicone O-rings are in fuel systems at temperatures up to +177°C and in applications where the dry-heat resistance of silicone O-rings are required. Fluorosilicone O-rings may also be exposed to petroleum based oils and/or hydrocarbon fuels. In some fuels and oils; however, the high temperature limit in the fluid list is more conservative because fluid temperatures approaching 200°C (390°F) may degrade the fluid, producing acids which attack fluorosilicone O-rings. For low temperature applications, fluorosilicone O-rings seal at temperatures as low as -73°C (-100°F).

Due to relatively low tear strength, high friction and limited abrasion resistance of these materials, they are generally recommended for static applications only. Fluorosilicones with high tear strength are also available. Some of these compounds exhibit improved resistance to compression set. Many fluorosilicone compounds have a higher than normal shrinkage rate so production molds for fluorosilicone products are often different from molds for nitrile.

3. FKM/ Fluorine Rubber: because fluorine rubber has the characteristics of high temperature resistance, oil resistance, high vacuum resistance and acid and alkali resistance, resistance to a variety of chemicals, it can be used as FKM Seal, FKM Gasket,  FKM O-Ring or FKM Accessories which has been applied in modern aerospace, missiles, rockets, space navigation, naval ships, atomic energy and other cutting-edge technology and automotive, shipbuilding, chemistry, petroleum, telecommunications, instruments, machinery and other industrial fields.

4. Perfluoroether Rubber: poor processing performance.It is used in the occasions where fluorine rubber is not competent and has harsh conditions.Make resistant to all kinds of media, such as rocket fuel, umbilical, oxidant, nitrous oxide, fuming nitric acid and other seals, used in aerospace, aviation, chemical industry, petroleum, nuclear energy and other industrial sectors.