Roksol STB is an anionic agent used for fatliquoring leather, mainly for chromium tanning. The product is a mixture of anionic emulsifiers and chlorinated organic compounds. It is a viscous liquid with a brown colour and a freezing point of -15°C, thus it does not require special storage and transport conditions. In water it forms milky O/W type emulsions (oil in water).
It can mix with all anionic and non-ionic lubricants. Moreover, it is also possible to mix it with cationic lubricants for the preparation of so-called multi-stage compositions. The product is soluble in alcohols, hydrocarbons and tetrachloroethylene. It is moderately resistant to acids, alkalis and electrolytes. Roksol STB is resistant to oxidation and sunlight.
The product has the ability to emulsify crude fats, such as raw fish oil, pig oil, spindle oil, etc. Due to the high content of emulsified ingredients in the product, the use of crude fat additives is not required in the preparation of fatliquoring mixtures. In special cases, its emulsifying capacity allows limited use of crude fat in a fatliquoring mixture.
The commercial product has a relatively low viscosity, which makes it easier to use under industrial conditions. However, Roksol STB has thixotropic properties and may become significantly ‘thickened’ if stored for a longer period of time. Nonetheless, it is a reversible process and the simple mixing of the thickened product restores its original viscosity.
The product has a high softening capacity for chrome or hybrid chrome tanned leather. Other advantages are good hydrophobic and weak equalising effect. Poor equalising effect enables obtaining pure and vivid leather colours with the use of anionic dyes. Leather greased with Roksol STB can be easily finished with water-based opaque paints. Preparation of working emulsions is very simple, and in individual cases it is possible to add commercial form of Roksol STB to lubricating devices.
The high rate of absorption of Roksol STB’s greasing components by chrome or hybrid chrome tanned leathers does not usually require any change in the physical parameters (temperature, time, bath ratio, etc.) of the industrial lubrication process.