Determination of film adhesion

Determination of paint film adhesion

The adhesion of a paint film refers to the ability of the paint film to bond with the surface of the object being painted. It is crucial to the quality and protective performance of the coating. Good adhesion can ensure that the paint film is not easy to fall off during use and effectively protects wood products.

According to the national standard GB4893.4 "Cross Cutting Method for Determination of Paint Film Adhesion on Furniture Surfaces", the method for measuring paint film adhesion is as follows:

Equipment and Materials:

Use a suitable paint film adhesion tester (e.g. Model EE) or other equivalent models.

Using a specific blade made of CrO _{3 alloy tool steel or CrO 6} material specified in the GB1299 standard , the blade thickness is 0.43 ± 0.03mm.

 Test steps:

Select three test areas on the sample, and use a blade and template to cut two sets of mutually perpendicular grid-shaped cuts on the paint film in the test area. Each set of cuts includes 11 cuts, with a length of 35mm and a spacing of 2mm. Make sure the cut penetrates into the substrate surface.

The cutting direction is at a 45-degree angle to the direction of the wood grain. Then gently use a paint brush to remove the floating debris from the paint film, place zinc oxide adhesive tape on the score, press it with your fingers, and then quickly peel it off. After this, use a 4x magnifying glass to observe the damage to the paint film from multiple angles.

The degree of damage to the paint film is rated according to the rating standards.

The purpose of the paint film adhesion measurement method is to ensure a strong bond between the paint film and the substrate to ensure the quality and service life of the coating. This kind of testing can help monitor the performance of the coating under different environments and stresses, so that necessary measures can be taken to ensure the stability and reliability of the coating.