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Paint adhesion
Paint adhesion
In industries of paint and coating, the paint adhesion tests is often used to determine if the paint or coating will adhere properly to the substrates on which they are applied.There are three different tests to measure the resistance of paints and coatings from substrates: Cross-cut test, scratch adhesion, and pull-off test.

1 Cross-Cut Test2 Scrape Adhesion3 Pull-off test4 See also5 Notes
A lattice pattern at right angles or X-cut (depending paint thickness) is used to measure the resistance of paints and coatings to the separation from substrates. The pattern is cut in the coating and penetrates through the substrate. A calibrated pressure sensitive tape is applied to the sample and removed. This test method is usually used to determine if the adhesion of a coating on a substrate at a level is usually sufficient. If the test sample is used on a multi-layer, the evaluation of the resistance to separation of the individual layers of the coating of the other can be realized.
Scrape Adhesion
The adhesion test scraping action determining the adhesion of organic coatings when applied to smooth surfaces and flat screen. It is useful to give votes on a number of coated panels showing significant differences in adherence. The materials being tested are applied to a uniform thickness of flat panels, essentially a kind of sheet metal. When the material has dried the adhesion is determined by pressing the panels under a curved stylus which are loaded with increasing amounts of weight until the coating is removed from the surface of the substrate

The adhesion of a coating or more sample coated with a paint product is measured by evaluating the minimum tensile stress required to detach or break the coating perpendicular to the substrate. Unlike other methods, this method maximizes tensile stress, so the results may not be comparable to the other. The test is performed by fixing loading apparatus (carts) perpendicular to the surface a coating of an adhesive. Then the testing apparatus is mounted on the loading apparatus and is then aligned perpendicular to apply a voltage to the test surface. The force that is applied gradually increases and is monitored until a cap is detached coating, or a prespecified value is reached.

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