Current status of film impact resistance test technology

Benzhang described the technical status of domestic and foreign general method standards and test instrument development for the impact resistance test of paint film, and briefly discussed the factors affecting the impact resistance test of paint film.

The impact resistance of the paint film, also known as the impact strength of the paint film , refers to the ability of the paint film coated on the substrate to undergo rapid deformation under the impact of a heavy hammer without cracking or falling off from the metal substrate . The flexibility of the paint film and its adhesion to the substrate .

In practical application , the paint film often inevitably collides with other objects due to various reasons . Therefore , it needs to have a certain impact strength as a protective material , but the impact resistance of the paint film is not related to other mechanical properties. There is a close correlation , so it has become one of the important testing items of its mechanical properties .

Discussion on Factors Affecting the Determination of Impact Resistance of Paint Film

1. The test plate must be closely attached to the surface of the anvil, so as to avoid the test plate jumping when it is impacted, which will affect the measurement results.

2. The impacted part of the test plate should be no less than 15mm from the edge.

3. The surface of the steel ball needs to be flat and smooth. If there is rust and wear, it should be replaced with a new steel ball.

4. When different test plate materials are used, the measurement results of the tinplate plate are usually lower than those of the thin steel plate, which is caused by the former being subjected to a slightly larger elastic expansion than the latter.

5. When the same test board is used, the more effectively the board is polished, the stronger the combination of the paint film and the board is, and the better the impact resistance of the paint film is.

6. In the case of the same height, the result of the downward impact of the paint film is more stringent than the result of the upward impact of the paint film, because the paint film has to undergo an outward stretching tension instantaneously during the reverse impact. This counter impact can be used to evaluate the adhesion and elasticity of the paint film.

7. For the paint film with impact resistance over 50cm, it can be measured by increasing the impact height or the weight of the weight. However, since the mechanical performance indicators of any paint film are interrelated and affect each other, it is necessary to take into account the measurement and evaluation. consider.

8. The impact resistance of the paint film is related to the ratio of pigment to base in the paint. It is generally believed that reducing the proportion of resin can improve the impact resistance index, but it may reduce the hardness index.