Roksol ST3K is a cationic auxiliary agent for tanning industry. It is a professional greasing preparation used for leather, mainly for chrome tanning. The product is a complex mixture of cationic surfactants with hydrophobic substances of fatty origin. It is offered in the form of an O/W emulsion (oil in water). It has the form of homogeneous, viscous liquid or paste with a yellow to light brown colour. It also has the ability to form a milky W/O (water in oil) emulsion.
Roksol ST3K is highly resistant to salts and acids, trivalent chromium compounds and hard water. The product can be mixed with all cationic and non-ionic lubricants. The stability of the emulsion with crude fats depends on the ratio of the components and the preparation method. Emulsions are obtained at a 1:2 ratio for bone oil and spindle oil (oil : Roksol ST3K). For the technical cod oil the ratio is 1:3 (oil : Roksol ST3K).
In most cases it is also possible to mix Roksol ST3K with anionic lubricants in the preparation of the so-called multi-charged compositions. The mixture of Roksol ST3K with clearly anionic compounds (synthetic and vegetable tanning agents, anionic dyes and dispersants, etc.), especially in acidic environments, leads to the breakdown of the emulsion and the formation of sediments. Roksol ST3K has the ability to emulsify crude fats such as fish oil, bone oil and spindle oil.
The product used on its own to lubricate chrome tanned leather provides it with softness, fulness and ductility, as well as a smooth and tight grain. It causes moderate bleaching of the natural colour of chrome tanned leather, while the colour obtained is completely resistant to sunlight. It should be noted that the product belongs to the group of fats that are resistant to yellowing under the influence of light.
As a cationic agent, Roksol ST3K does not have an equalising effect on anionic dyes and enables obtaining vivid and richly hued shades of colour. Its effect on leather depends on the type of tanning and the surface charge of the leather. In the case of pure chrome tanned leather, Roksol ST3K penetrates quickly and easily into the skin tissue, giving the effect of even lubrication of the entire leather cross-section, which translates into good softness and fulness of the finished product. However, in the case of anionic tanned leather (vegetable tanning, syntan tanning, etc.) and chrome tanned leather treated with anionic agents (vegetable and synthetic tanning agents, direct acid dyes, sulphated and sulfonated fats, etc.) Roksol ST3K is deposited on their surface, giving the effect of strong lubrication of the outer layers.