Recommended application of fumed silica in coatings

Fumed silica is a versatile and highly effective additive that can provide one or more important properties to coatings.

 

1. Rheology

Rheology is one of the most important properties of coatings. It can affect the workability, storage stability and appearance of the coating.

 

Rheology additives can provide thixotropy to the coating to increase the viscosity of the coating, while the coating can have good workability when shear force is encountered.

 

Pyrogenic silica is a very good rheology additive. The surface of fumed silica has a large number of hydroxyl groups, which form hydrogen bonds between the fumed silica and form a network structure in the coating. The net structure can effectively prevent the paint from sagging. It makes the coating film more uniform and beautiful.

 

2. Anti-settling

Various color fillers are used in the preparation of coatings. In order to ensure the uniform dispersion of color fillers, prevent settling and maintain good leveling performance of coatings, formulators will use various anti-settling agents.

 

The interaction between the fumed silica will form hydrogen bonds, which will result in a network structure of the coating. This network structure ensures the suspension of the gas silica so that the particulate matter in the coating system is less likely to aggregate and undergo phase separation.

Gaseous silica can well prevent the sinking of the color filler in the coating, thus ensuring the stability of the system.

 

3. Dispersion aid

The nanometer size of fumed silica gives it a high surface energy, which can be adsorbed on the surface of the powder to improve the fluidity of the powder and the dispersion performance of the coating.

 

By selecting different grades of fumed silica, formulators can achieve a balance between coating sagging, leveling and thixotropy, and meet the requirements of high solid content coatings and low VOC coatings. When properly applied, fumed silica can improve the desired performance of a coating without causing negative effects.

 

Listed below are the recommended grades and properties of CAB-O-SIL fumed silica for use in coatings.

 

4. Hydrophilic fumed silica

 

Model: M-5

Specific surface area (m²/g): ~200

 

Model：D-2150

Specific surface area（㎡/g）：~260

 

Model：H-300

Specific surface area（㎡/g）：~300

 

Model：CLARUS-3160

Specific surface area（㎡/g）：~380

 

5. Hydrophobic fumed silica

 

Model：TS-530

Specific surface area（㎡/g）：~225

 

Model：TS-610

Specific surface area（㎡/g）：~125

 

Model：TS-720

Specific surface area（㎡/g）：~115

 

Note: 1、The above data are only typical values, not the technical specifications of the product.

2、The above information only describes the product performance, but does not guarantee the product performance. Due to the different composition of the end product formula and process conditions, it is recommended that the product performance and applicability described above be tested to determine whether it can achieve your expected use.

3、For the safe use of the products, please refer to the Material Safety Data Sheet “MSDS”.