Optical grease refers to a plastic paste-like substance that specifically lubricates the friction parts of the optical instrument movement, or prevents dust from falling on the inner surface of the optical instrument cavity and dust collection.
Used for some precision optical instruments, like biological microscopes, photographic (camera) lenses, military optical instruments, etc.
The quality of optical grease has a lot to do with its own composition.
The performance evaluation of the quality is mainly including penetration, dropping point, low temperature resistance, chemical stability, colloidal stability, corrosion resistance, volatility, oil layer retention, diffusivity and mildew resistance.
The quality of grease is directly related to the main performance of the lubricant used. Lubricating oil directly plays the role of lubricating and reducing friction. Its viscosity, viscosity-temperature characteristics, freezing point, flash point, acid value, etc. have a greater impact on the properties of the grease.
The viscosity can directly reflect the frictional force in the lubricating oil molecule; lubricating oil with good viscosity-temperature characteristics has a large viscosity-temperature index, and its viscosity changes little when the temperature rises or falls.
The freezing point can reflect the low temperature resistance of the oil; the flash point shows the high temperature resistance of the lubricating oil; the acid value can be used to measure the corrosion resistance of the lubricating oil to metals. Generally, the acid value is large, and it contains many low molecular weight organic acids. , The corrosion to metal is more serious, should choose a small group value or neutral oil to make optical grease.
Optical grease is different from other industrial greases. It requires the adhesion of the grease to be fixed on the lubricating part, and will not squeeze the grease out of the scope of action due to the rotation and stretching of the friction part; damping is used in the optical instrument The function is more important. It can not only maintain the working condition of the optical instrument in use, but also bring a very comfortable feel to the user.
Adhesion and damping complement each other in the design of the optical grease formula. Adjusting the relationship between the two can bring very ideal use effects to optical instruments.
Optical grease should have good dispersion resistance. The so-called anti-dispersion property refers to the ability of the grease to absorb the base oil. The optical grease with good anti-dispersion property can ensure that the base oil will not diffuse to non-lubricated parts due to capillary action (the so-called oil creep phenomenon) and pollute other optical systems To affect the normal use of optical instruments.
Low volatility and good mildew resistance.
The low volatility of optical grease can ensure that the instrument is not contaminated by oil mist during use; and the good anti-mold property mainly prevents mold from growing in the optical instrument. Optical grease should have a certain operating temperature range.
In principle, optical grease is required to meet the requirements of -40～80℃, but for some general civilian optical instruments, the low temperature can be adjusted appropriately according to the actual working environment.
