An Adhesion Promoter, also known as an adhesive modifier or surface treatment agent, is a substance used to improve the bonding properties between two surfaces. This is typically achieved by enhancing the surface energy of the material, increasing the wetting ability of the adhesive, or creating chemical reactions at the interface that promote stronger intermolecular interactions.

Adhesion promoters are commonly used in industries such as automotive manufacturing, construction, packaging, and adhesives production. They can be in the form of liquids, powders, or gels and are applied before the main adhesive is used. The type of adhesion promoter used depends on the specific requirements of the application, including the nature of the substrates involved and the desired strength and durability of the bond.

For example, in the context of bonding plastics, rubber, or metals, different types of adhesion promoters can be used to overcome the natural resistance to adhesion due to differences in chemical composition and surface energy. These substances might include silanes, titanates, or other reactive compounds that chemically modify the surface, making it more receptive to the adhesive.

In summary, adhesion promoters play a crucial role in ensuring strong and reliable bonds, which is essential for the functionality and longevity of many products and structures.