Application of Evonik Silica in Leather Finishing Agents

Release Time:

2021-09-15

Evonik has two types of silicas used in leather finishing agents:

^{One type is fumed silica (AEROSIL ®} ) with primary particle size in the nanometer range , such as AEROSIL ^® 150, AEROSIL ^® 200, AEROSIL ^® TT 600, AEROSIL ^® R 972, etc.;

The other type is micron-sized silica matting powder (ACEMATT ^® ), including precipitated silica such as ACEMATT ^® OK 412, ACEMATT ^® OK 607, etc., and also includes three fumed silicas ACEMATT ^® TS100, ACEMATT ^® 3300, ACEMATT ^® 3400.

Both types of silica have a matting effect when used in leather finishing agents, but due to differences in production processes, their performance in leather finishing agents is also different.

The silicas used by Evonik in leather finishes are synthetic, amorphous, fluffy white powders.

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Fill power (10g each)
micro structure
Application characteristics in leather finishing agents	Primary particle size 7~40nm Low extinction efficiency Good transparency Polishing and washing effect is good	Particle size (d50) 4.4~14.5 um High extinction efficiency Good scratch and wear resistance

Although both are synthetic amorphous, fluffy white powders, fumed silica is more fluffy than precipitated silica.

The performance in leather finishing agents is as follows : Generally speaking, the blackness and transparency of leather finishing agents adding fumed silica are better than those adding precipitated silica. This has a lot to do with the production process and particle size of silica.

Silica with different particle sizes can be compounded to improve blackness and transparency.

Generally speaking, among leather finishing agents, fumed silica has good blackness and transparency, but due to its small primary particle size, its matting efficiency is relatively low, and its scratch and wear resistance is not ideal. Therefore, fumed silica is often used for leather that requires high blackness and high transparency, and has good polishing and washing effects.

Precipitated silica has a relatively large particle size, high extinction efficiency, and good scratch and wear resistance. However, due to differences in production processes, the blackness and transparency are slightly inferior to those of fumed silica.