Silica, also known as precipitated silica or fumed silica, is an important inorganic chemical raw material. It is widely used in rubber, coatings, inks, cosmetics and other fields due to its unique physical and chemical properties. The Hydrophilic and Hydrophobic of silica are one of its important properties, which directly affect the application effect in coatings. The following is a detailed study of the Hydrophilic and Hydrophobic of silica in coatings:

1. Hydrophilic of silica

Definition and characteristics:

Hydrophilic silica, also known as activated silica, has a chemically treated surface with hydrophilic groups such as hydroxyl groups, so it has strong hygroscopicity and good dispersibility.

Application in coatings:

Hydrophilic silica is usually used in water-based coatings to form a stable suspension, which is beneficial to the preparation and construction of coatings.

It can improve the gloss, hiding power and stability of coatings.

In oil-based coatings, hydrophilic silica can also be used as a filler to increase the gloss and hiding power of the coating.

2. Hydrophobic of white carbon black

Definition and characteristics:

Hydrophobic white carbon black, also known as inactive white carbon black, has a special surface treatment and has good Hydrophobic. It is not easy to absorb water, thus maintaining stable physical and chemical properties.

Modification method:

Common modification methods include silane coupling agent treatment, fatty acid modification, etc. These methods can introduce hydrophobic groups on the surface of white carbon black to reduce its surface energy.

Application in coatings:

Hydrophobic white carbon black is used as a filler in water-based coatings to improve the water resistance and stability of the coating.

In oil-based coatings, hydrophobic white carbon black can further improve the performance of the coating due to its good dispersibility and compatibility.

Hydrophobic white carbon black can also be used as a thickener, thixotropic agent and anti-settling agent to improve the fluidity and stability of the coating, and improve the covering power and adhesion of the coating.

3. Comparison of Hydrophilic and Hydrophobic

Hygroscopicity:

Hydrophilic white carbon black has strong hygroscopicity and is suitable for coatings that need to absorb water or have good compatibility with aqueous media.

Hydrophobic silica is not easy to absorb water and can maintain the stability of the coating in a humid environment.

Dispersibility:

Hydrophilic silica is easy to disperse in water to form a stable suspension.

Hydrophilic silica has good dispersibility in organic solvents and is suitable for the enhancement and modification of organic materials such as oily coatings.

Application areas:

Hydrophilic silica is more suitable for water-based coatings and certain specific coatings that require hygroscopicity.

Hydrophilic silica is more suitable for coatings with strict requirements on water resistance, such as exterior wall coatings, waterproof coatings, etc.

4. Selection suggestions

When choosing silica, the appropriate type should be selected according to the specific needs and application scenarios of the coating. For example, for water-based coatings that require good wettability and dispersibility, hydrophilic silica can be selected; while for coatings that need to improve water resistance and stability, hydrophobic silica can be selected.

In summary, the Hydrophilic and Hydrophobic of silica have an important influence on its application in coatings. Through reasonable selection and application, the performance advantages of silica can be fully utilized to improve the overall quality and performance of the coating.