The performance evaluation of the coating film is a key step to ensure its quality and suitability. The film may be subjected to impact force in actual use, so the impact strength test is an important index to evaluate the ability of the film to resist transient deformation and maintain integrity. This paper will introduce the concept of impact strength of coating film, test method and its significance in the evaluation of coating film quality.

1. Concept of film impact strength

The impact strength of the film refers to the ability of the film to resist instantaneous deformation without cracking and falling off under the action of high-speed impact force. This performance index reflects the flexibility of the film and the binding force on the substrate. In practical applications, the film may be subjected to external forces such as impact and collision of objects, so the impact strength of the film is crucial to protect the substrate and extend the service life of the film.

Film impact tester evaluates film impact strength

2. Test method of impact strength of coating film

According to GB/T 1732-93, the impact strength of the film can be tested by impact experiments. Impact testers are designed to follow certain specifications, including:

Weight: 1000g

Groove diameter: 15 mm ± 0.3mm

Punch into the groove depth: 2mm ± 0.1mm (need to be corrected)

Maximum sliding height of the weight: 50cm

The results of impact experiments are usually expressed as N●cm. The parameters of the impact tester may be different in different countries and standards. For example, the impact test defined in the ISO 6272-1993 standard uses a weight of 1kg and a height of 1m.

3. Quality assessment after test

After the impact test was completed, the quality of the film was evaluated. Common assessment methods include:

Visual observation: Use a 4x magnifying glass to observe whether there are cracks and damage on the surface of the film. However, extremely fine cracks may be difficult to observe and judge by this method.

Wetting observation of the film: In some cases, after wetting the film in CuSO aqueous solution for a period of time, observe whether copper or rust color appears to determine whether there is a fine crack.

Film impact tester evaluates film impact strength

4. Significance of impact strength of coating film

The impact strength test of coating film is of great significance in the quality evaluation of coating film. The high impact strength means that the film can maintain its integrity under external impact, preventing cracks and peeling, thus extending the service life of the film. In addition, the impact strength is also related to the flexibility of the film and the binding force on the substrate, which is crucial for the stability and reliability of the film under various environmental conditions.

Sum up

The impact strength of the coating film is a key performance index to evaluate the deformation resistance and integrity retention ability of the coating film under the action of high-speed impact force. The impact strength test evaluates the resistance of the film to transient deformation and binding force by simulating the impact under actual conditions of use. Testing and evaluating the impact strength of the coating helps to ensure that the coating quality meets the expected standards, thereby protecting the substrate and extending the service life of the coating.