Classification and Characteristics of Leveling Agents
After a coating is applied, it goes through a flow, drying and film-forming process to gradually build a smooth, uniform film. However, during levelling and film formation the coating frequently develops defects such as shrinkage craters and pinholes. This is where a leveling agent is needed — to give the coating an appropriate surface tension and to reduce the surface-tension gradient.
There Are Generally Several Types of Leveling Agents
1. Defoaming leveling agents: mainly used to eliminate the bubbles generated when medium- and high-viscosity coatings are used with stirring, as well as the air bubbles produced during coating application by curtain coating, brushing and spraying.
2. Special foam-suppressing leveling agents: besides suppressing the bubbles generated during coating production and spraying, these agents also level the film so that recoating does not suffer from poor intercoat adhesion.
3. Slip leveling agents: improve the clarity, gloss and smooth feel of the film.
4. Rapid foam breakers: in addition to helping the coating break foam rapidly during spray and dip application, they moderately increase film brightness and dry slip, inhibit flooding and floating, and prevent craters.
5. Deaerators for solvent-borne coatings: eliminate bubbles and depressions, produce a flat film and improve the film’s scratch and mar resistance.
The above describes the classification and characteristics of leveling agents. We hope it is helpful to you.
