What is the Difference Between Adhesion Promoter and Primer

The key difference between adhesion promoter and primer is that adhesion promoters are additives for the paint to promote the adhesion of the paint film to the substrate, whereas adhesion primers are dilute solutions to conserve the surface of a material having bonded in a later stage.

Adhesion promoters and adhesion primers are important substances in paints and coatings.

1. Overview and Key Difference
2. What is an Adhesion Promoter
3. What is an Adhesion Primer
4. Adhesion Promoter vs Primer in Tabular Form
5. Summary – Adhesion Promoter vs Primer

What is an Adhesion Promoter?

An adhesion promoter is an additive for paint that is useful in promoting the adhesion of the film to the substrate. Adhesion can be described as the resistance of the coating to being removed from the substrate. An adhesion promoter has an affinity for the substrate and the applied coating and can form a permanent and strong bonding.

The lack of adhesion promoters can typically make the properties of the coating insufficient to meet the final performance requirements of the paint. Therefore, adhesion and adhesive strength are an important combination of various factors between the paint material and the substrate. These factors include mechanical adhesion, physical mechanisms at a molecular level at the interface, thermodynamic mechanisms, etc.

Generally, an adhesion promoter can enhance film adhesion by its affinity toward the substrate and the liquid coating. Moreover, wetting the liquid coating to the substrate is also a key factor. However, a perfect adhesion will also depend on factors like paint formulation, application conditions, type of surface and its properties, surface preparation, etc.

What is an Adhesion Primer?

An adhesion primer is a dilute solution of an adhesive in an organic solvent. We can apply this solution to an adherend that produces a dry film with a thickness of about 0.0015 mm. Moreover, an oil-based primer will stick to almost any surface. But a water-based primer can sometimes be scratched-off.

We most commonly use plastic primers that are known named as plastic adhesion promoters. They are products useful in optimizing the adhesion of subsequent coats of paint, including putty or filler paint to a surface.

Generally, adhesion primers help to conserve the surface of a material having bonded in a later stage. Therefore, it provides more flexibility in the manufacturing process. We can consider adhesive primers as strongly diluted adhesives combined with a coupling agent such as silane. The main function of this mixture is to wet the freshly prepared surface easily.

What is the Difference Between Adhesion Promoter and Primer?

Adhesion promoters and adhesion primers are important substances in paints and coatings. The key difference between adhesion promoter and primer is that adhesion promoters are additives for the paint to promote the adhesion of the paint film to the substrate, whereas adhesion primers are dilute solutions to conserve the surface of a material having bonded in a later stage.

The following table summarizes the difference between adhesion promoter and primer.

Summary – Adhesion Promoter vs Primer

An adhesion promoter is an additive for paint that is useful in promoting the adhesion of the film to the substrate. An adhesion primer, on the other hand, is a dilute solution of an adhesive in an organic solvent. The key difference between adhesion promoter and primer is their function; adhesion promoters act as additives for the paint to promote the adhesion of the paint film to the substrate, but adhesion primers conserve the surface of a material having bonded in a later stage.

Reference:

1. “Select Adhesion Promoters for Coatings.” Special Chem Coatings.
2. “Primer for Plastics: How to Paint a New Plastic Part.” SINNEK Academy – Practical Training for the Professional Auto Body Painter.
3. “Adhesive Primer.” An Overview | ScienceDirect Topics.