In response to customer requests regarding the release of oil on the surface of greases, the company explains. The exudation of oil – leakage of oil from lubricating grease during storage or as result of mechanical/dynamical or temperature stress.

Considering the physical stability of greases, we’re able to speak, first of all, about their stability as colloid systems. Colloid solutions sooner or later show signs of decay (syneresis), which is expressed in the beginning in the exudation, and then the separation of the liquid component. However, with a high concentration of thickener over a number of years, signs of such decay may not be detected.

“When researching a grease, especially immediately after producing in the factory or after a relatively short period of time, it’s important to determine whether the grease will be colloidally stable or whether it will start to release oil after a while. In the last case, it would be extremely important to be able to determine in advance whether this decay will be limited to the release of a small amount of oil, after which there will be a balance. This doesn’t pose a great danger to the grease performance. Whether the decay continues, it will make impossible the grease application.” (B.M. Rybak “The Analysis of oil and petroleum products”, M, 1962.)

The “Colloid stability” indicator sets the standard for maintaining the performance of the grease during the warranty period of storage, but it’s possible to separate small amounts of oil on the surface of the grease (exudation).

Additionally, it should be note:

“Polysiloxanes have a number of interesting properties one of them it is the critical wetting surface tension which is higher than the liquid surface tension. That’s means that the polymer will spread over its own absorbed film, a so-called creep process.” (“Constructive properties of the plastics” edited by L.I. Galickay, M, Chemistry, 1967, c.290-292)

This property can be an advantage in some applications, because it means that the silicone liquid will easily provide a surface coating to protect the metal or contribute to the mold connector.

On the other hand, the liquid when spreading fills the deepenings on the surface of the grease. If there are no signs of liquid exudation in greases based on silicon-organic oils, then, with a high probability we can talk about replacing silicon-organic with a cheaper product, which is not providing the required frost and heat resistance. Said applies to greases such as: ЦИАТИМ-221, ОКБ-122-7, ВНИИ НП-207, ВНИИ НП-219.

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