4 Types of Additives in Paints

25th December 2023

What is additives in paints?

Coatings includes 4 components, namely resins (binders) , additives (such as PU hardeners), solvents and pigment.  Additives in paints, also known as coating auxiliary materials, play a crucial role in enhancing coating performance and facilitating film formation. Additives are used in minimal quantities to ensure the performance throughout the preparation, storage, and application processes. They are indispensable components in water-based, high-performance, and highly decorative coatings.

Unlike solvents, which can evaporate after film formation, additives will remain as integral components within the coating. Thus, they may give adverse effects on the final coating. For instance, emulsifiers are indispensable in emulsions, yet the migration and hydrophilicity of residual emulsifiers in the coating can inevitably impact water resistance and adhesion. Understanding these nuances is crucial for optimizing coating formulations.

pouring additives in paints

How much additives is in paints?

Typically, various additives would be used in coating, with the content ranging from 0.01% to 5% of the formulation. Additives have different structures and physicochemical properties, and many of them are diverse types of surfactants. They can either work together synergistically or counteract each other in paints. Furthermore, additives interact in complex ways with film-forming resins, pigments, and dispersing media. Therefore, choosing the right combination of additives requires collaboration between additive suppliers and formulators.

4 Types of Paint Additives

There are typically 4 types of paint additives according to their roles in different stages of the coating process.

Coating Production

Additives are added to in the process of coating production to adjust the performance. Examples include:

  • Wetting Agents enhance the coating's wetting properties on substrates, ensuring uniform coverage and improved adhesion.
  • Dispersants promote the uniform dispersion of pigments and solid particles in the liquid phase, preventing settling and ensuring color consistency.
  • Emulsifiers, crucial in emulsion coatings, stabilize and evenly disperse water and oil-based components.
  • Defoamers prevent the formation of bubbles in the coating, ensuring a smooth surface.

Storage and Transportation

Additives used to ensure the performance stability of coating during storage and transportation. Examples include:

  • Anti-Settling Agents prevent settling of pigments or other solid particles in the coating during storage, ensuring a uniform dispersion.
  • Anti-Skinning Agents prevent the formation of a skin on the coating surface when exposed to air during storage, maintaining cleanliness at the container opening.
  • Anti-Floating, Anti-Flocculating Agents prevent color floating or flocculation in the coating, maintaining color consistency.
  • Anti-Freezing Agents prevent the coating from freezing under low-temperature conditions, ensuring it remains unaffected by freezing during storage and transportation.
  • Preservatives inhibit microbial contamination of the coating during storage, preserving the quality and stability of the coating.

Application and Film-formation

Additives are used to enhance the coating properties during applications.

  • Curing Agents accelerate the curing or cross-linking process, ensuring proper film formation.
  • Leveling Agents  enhance the smoothness of the coating surface, reducing brush or roller marks and ensuring an even finish.
  • Matting Agents reduce gloss, providing a matte or satin appearance to the coating.
  • Anti-Sag Agents prevent the coating from sagging or dripping when applied on vertical surfaces.
  • Film-Forming Aids assist in the formation of a continuous and uniform film, improving coating integrity.

Enhancing Specific Properties 

Additives are also added into the coating formulations to enhance specific properties.

  • UV Absorbers absorb ultraviolet (UV) light, protecting the coating from UV-induced degradation and enhancing its durability.
  • Heat Stabilizers help the coating withstand high temperatures, preventing thermal degradation and maintaining performance.
  • Scratch-Resistant Agents enhance the coating's resistance to scratches and abrasion, improving surface durability.
  • Hydrophobic Agents make the coating water-repellent, enhancing water resistance and durability.