The crude phospholipid component contains a certain amount of neutral oil, which can lubricate the leather fiber and impart a certain softness to the leather. The phospholipid itself has an affinity for the skin collagen, and an adsorption film and a chemical sorption film can be formed on the skin fiber. These films can both act as a lubricating fiber and prevent oxidation of the oil, thereby protecting the surface.

Plasticization

Phospholipids have been shown to have a plasticizing effect on proteins. Therefore, when the leather is fatliquored, the phospholipid can be used as a softener for the protein, a plasticizer. By increasing the plasticizing effect on the collagen fibers, the softness and elasticity of the finished leather can be improved. The plasticization of phospholipids can also be applied to the production of leather finishes such as casein.

Thickening effect

The thickening effect of phospholipids is not to be explained simply by physical "filling", but it seems more appropriate to use chemical "filling" to explain. The phospholipid is a phosphoric acid-containing surfactant, and the molecule contains other active groups in addition to the phosphate group, and therefore, it can chemically combine with the collagen fibers to form a complex. Of course, the possibility of it forming a complex with a central ion such as Cr3+ is not excluded. According to the data, a central (multivalent) metal ion such as Cr3+ or A l3+ can form a complex with a compound containing a -COOH or -OPO 3H2 functional group. It has been reported that the chromatographic extract of the test leather using the phospholipid fatliquor is lower than that of the comparative leather, indicating that the phospholipid has complexing activity.

The application of phospholipids in the leather industry

Fatliquoring is an important process in the production of leather, and the fatliquor used in this process is mostly made from animal and vegetable oils. Phospholipids are derived from animal and vegetable oils and fats. Their molecular structure is similar to that of natural oils and fats. They are also glycerides and have surface activity. Therefore, the fatliquoring process has become a major application field in leather production.

Phospholipids are derivatives of fatty acids and have the characteristics of oils and fats. Therefore, under certain conditions, various derivatives are easily obtained by saponification, halogenation, sulfation, sulfonation, oxidation, etc., so that they have a place in leather fatliquoring materials. It is expected to penetrate into the production applications of other leather materials such as finishes.