Adhesion is an important physical property of a coating, and related tests are often regarded as an indicator of proper bonding between the substrate and the primer and/or between the coatings. Adhesion testing may be a requirement for coating specifications, or it may be used in the laboratory to verify the performance of the coating system. Adhesion test can also be used to evaluate whether the coating system has been used for a long time, whether its performance has declined, whether it needs repair, whether the output coating should be strengthened with topcoat, in addition, it is also often used for coating Invalid investigation. Regardless of the purpose of the test, the adhesion test must follow its standard test method (procedure) in order to obtain consistent results
ASTM D3359 “Standard Test Method for Measuring Adhesion by Tape (Tape Method)” and ASTM D6677 “Standard Test Method for Evaluating Adhesion by Blade (Blade Method)” may be the most commonly used to evaluate the adhesion of coatings to substrates Two methods. Although it is generally considered that the tape method and the blade method are more subjective than the tensile adhesion test, the tape method and the blade method can indeed show the true adhesion properties of the coating. Experience has shown that sometimes coatings that are easily picked up by blades, tape or even fingers have high tensile adhesion values. It seems that the two seem to contradict each other. This is mainly caused by the different directional forces applied to the coating during the test. .