Silicone grease
Encyclopedia
Silicone grease is a waterproof grease
made by combining a silicone oil
with a thickener. Most commonly, the silicone oil is polydimethylsiloxane
and the thickener is amorphous fumed silica
. Using this formulation, silicone grease is a translucent white viscous paste, with exact properties dependent on the type and proportion of the components.
s. Additionally, silicone grease does not swell or soften the rubber, which can be a problem with hydrocarbon
based greases. It functions well as a corrosion-inhibitor and lubricant for purposes that require a thicker lubricant, such as the operating mechanism of the M1 Garand
rifle.
Thermal grease
often consists of a silicone grease base, along with added thermally conductive fillers. It is used for heat transfer abilities, rather than friction reduction.
Special versions of silicone grease are also used widely by the plumbing industry in faucets and seals, as well as dental equipment. These special versions are formulated using components not known to be an ingestion hazard. Electrical utilities use silicone grease to lubricate separable elbows on lines which must endure high temperatures. Silicone greases generally have a temperature range of -40 to 400 °C.
s, as is typically used in laboratory glassware
. Although silicones are normally assumed to be chemically inert, several historically significant compounds have resulted from unintended reactions with silicones: for example, the first salts of crown ether
s (OSi(CH3)2)n (n = 6, 7) were produced by reactions resulting from contacting organolithium and organopotassium compounds with silicone greases.
, would damage certain products, such as latex rubber condoms and gaskets on drysuits. It can be used to lubricate fountain pen mechanisms, preserve O-rings in flashlight
s, to seal waterproof watches and for O-rings on air rifles. Silicone-based lubricants are also commonly used for remote control hobbies.
Various household uses include lubricating light bulb threads to facilitate removal and discourage stuck bulbs (especially in outdoor lighting), door hinges, shower heads, threads on bolts, garden hose threads or any thread or mechanism that can be lubricated.
s should not be coated with dielectric grease prior to being mated. Dielectric grease is, however, often applied to electrical connector
s, particularly those containing rubber gaskets, as a means of lubricating and sealing rubber portions of the connector.
The widest use of dielectric grease is in high-voltage connections associated with spark plugs. The grease is applied to the rubber boot of the plug wire. This helps the rubber boot slide onto the ceramic insulator of the plug. The grease also acts to seal the rubber boot, while at the same time preventing the rubber from becoming stuck to the ceramic. Generally spark plugs are located in areas of high temperature, and the grease is formulated to withstand the temperature range expected.
Another common use of dielectric grease is on the rubber mating surfaces or gaskets of multi-pin electrical connectors used in automotive and marine engines. The grease again acts as a lubricant and a sealant on the nonconductive mating surfaces of the connector. It is not recommended to be applied to the actual electrical conductive contacts of the connector because it could interfere with the electrical signals passing through the connector.
Grease (lubricant)
The term grease is used to describe semisolid lubricants. Although the word grease is also used to describe rendered fat of animals, in the context of lubrication, grease typically applies to a material consisting of a soap emulsified with mineral or vegetable oil...
made by combining a silicone oil
Silicone oil
A silicone oil is any polymerized siloxanes with organic side chains. They are formed of alternating silicon-oxygen atoms or siloxane, rather than carbon atoms . Other species attach to the tetravalent silicon atoms, not to the divalent oxygen atoms which are fully committed to forming the...
with a thickener. Most commonly, the silicone oil is polydimethylsiloxane
Polydimethylsiloxane
Polydimethylsiloxane belongs to a group of polymeric organosilicon compounds that are commonly referred to as silicones. PDMS is the most widely used silicon-based organic polymer, and is particularly known for its unusual rheological properties. PDMS is optically clear, and, in general, is...
and the thickener is amorphous fumed silica
Fumed silica
Fumed silica, also known as pyrogenic silica because it is produced in a flame, consists of microscopic droplets of amorphous silica fused into branched, chainlike, three-dimensional secondary particles which then agglomerate into tertiary particles. The resulting powder has an extremely low bulk...
. Using this formulation, silicone grease is a translucent white viscous paste, with exact properties dependent on the type and proportion of the components.
Use in industry
Silicone grease is commonly used for lubricating and preserving rubber parts, such as O-ringO-ring
An O-ring, also known as a packing, or a toric joint, is a mechanical gasket in the shape of a torus; it is a loop of elastomer with a disc-shaped cross-section, designed to be seated in a groove and compressed during assembly between two or more parts, creating a seal at the interface.The O-ring...
s. Additionally, silicone grease does not swell or soften the rubber, which can be a problem with hydrocarbon
Hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
based greases. It functions well as a corrosion-inhibitor and lubricant for purposes that require a thicker lubricant, such as the operating mechanism of the M1 Garand
M1 Garand
The M1 Garand , was the first semi-automatic rifle to be generally issued to the infantry of any nation. Called "the greatest battle implement ever devised" by General George S...
rifle.
Thermal grease
Thermal grease
Thermal grease is a viscous fluid substance, originally with properties akin to grease, which increases the thermal conductivity of a thermal interface by filling...
often consists of a silicone grease base, along with added thermally conductive fillers. It is used for heat transfer abilities, rather than friction reduction.
Special versions of silicone grease are also used widely by the plumbing industry in faucets and seals, as well as dental equipment. These special versions are formulated using components not known to be an ingestion hazard. Electrical utilities use silicone grease to lubricate separable elbows on lines which must endure high temperatures. Silicone greases generally have a temperature range of -40 to 400 °C.
Use in the chemical laboratory
Silicone grease is widely used as a temporary sealant and a lubricant for interconnecting ground glass jointGround glass joint
Ground glass joints are used in laboratories to quickly and easily fit leak-tight apparatus together from commonly available parts. For example, a round bottom flask, Liebig condenser, and oil bubbler with ground glass joints may be rapidly fitted together to reflux a reaction mixture...
s, as is typically used in laboratory glassware
Laboratory glassware
Laboratory glassware refers to a variety of equipment, traditionally made of glass, used for scientific experiments and other work in science, especially in chemistry and biology laboratories...
. Although silicones are normally assumed to be chemically inert, several historically significant compounds have resulted from unintended reactions with silicones: for example, the first salts of crown ether
Crown ether
Crown ethers are cyclic chemical compounds that consist of a ring containing several ether groups. The most common crown ethers are oligomers of ethylene oxide, the repeating unit being ethyleneoxy, i.e., -CH2CH2O-. Important members of this series are the tetramer , the pentamer , and the hexamer...
s (OSi(CH3)2)n (n = 6, 7) were produced by reactions resulting from contacting organolithium and organopotassium compounds with silicone greases.
Consumer uses
Silicone-based lubricants are often used by consumers in applications where other common consumer lubricants, such as petroleum jellyPetroleum jelly
Petroleum jelly, petrolatum, white petrolatum or soft paraffin, CAS number 8009-03-8, is a semi-solid mixture of hydrocarbons , originally promoted as a topical ointment for its healing properties...
, would damage certain products, such as latex rubber condoms and gaskets on drysuits. It can be used to lubricate fountain pen mechanisms, preserve O-rings in flashlight
Flashlight
A flashlight is a hand-held electric-powered light source. Usually the light source is a small incandescent lightbulb or light-emitting diode...
s, to seal waterproof watches and for O-rings on air rifles. Silicone-based lubricants are also commonly used for remote control hobbies.
Various household uses include lubricating light bulb threads to facilitate removal and discourage stuck bulbs (especially in outdoor lighting), door hinges, shower heads, threads on bolts, garden hose threads or any thread or mechanism that can be lubricated.
Dielectric grease
Dielectric grease is a nonconductive grease. As such, it does not enhance the flow of electrical current. Thus electrical conductorElectrical conductor
In physics and electrical engineering, a conductor is a material which contains movable electric charges. In metallic conductors such as copper or aluminum, the movable charged particles are electrons...
s should not be coated with dielectric grease prior to being mated. Dielectric grease is, however, often applied to electrical connector
Electrical connector
An electrical connector is an electro-mechanical device for joining electrical circuits as an interface using a mechanical assembly. The connection may be temporary, as for portable equipment, require a tool for assembly and removal, or serve as a permanent electrical joint between two wires or...
s, particularly those containing rubber gaskets, as a means of lubricating and sealing rubber portions of the connector.
The widest use of dielectric grease is in high-voltage connections associated with spark plugs. The grease is applied to the rubber boot of the plug wire. This helps the rubber boot slide onto the ceramic insulator of the plug. The grease also acts to seal the rubber boot, while at the same time preventing the rubber from becoming stuck to the ceramic. Generally spark plugs are located in areas of high temperature, and the grease is formulated to withstand the temperature range expected.
Another common use of dielectric grease is on the rubber mating surfaces or gaskets of multi-pin electrical connectors used in automotive and marine engines. The grease again acts as a lubricant and a sealant on the nonconductive mating surfaces of the connector. It is not recommended to be applied to the actual electrical conductive contacts of the connector because it could interfere with the electrical signals passing through the connector.