As a key element of surface protection and beautification, the coating film not only needs to have good mechanical properties, but also must resist the infringement of external factors such as light, heat and electricity during use. Among them, color retention refers to the ability of the coating to maintain its original color under exposure to light. The detection of color retention is important for various applications, from automotive painting to architectural decoration, to ensure that the film does not fade or change color under light conditions. This paper will introduce the importance of color retention and detection methods, especially the instrument determination method using GB/T 9761 method.

In many application scenarios, the color of the film is often an important part of the appearance of the product, and it is also closely related to the brand identity and design concept. Whether it is cars, home furniture or buildings, consumers usually expect the color of the film to be durable and bright, and will not change due to long-term light. In addition, color consistency is also crucial for quality control in production, especially when mass production is required to ensure that the color of each product remains consistent.

The color retention of the film was measured by a color difference meter

Detection method
In order to evaluate the color retention of the film, the visual method and the instrument method are usually used. Among them, the instrument method, in accordance with the provisions of GB/T 9761, is a more accurate and reproducible method, especially for applications requiring quantified data.

The specific detection steps are as follows:

Prepare the test film template to ensure that the color meets the product requirements.

Place the color difference meter on the template to ensure that the light source is stable.

Use a color difference meter to select the appropriate measurement mode and record the color value before irradiation.

The coating template is exposed to light for a certain time to simulate actual use.

The color value after irradiation was measured again with a color difference meter.

Calculate the color retention, that is, the color value after irradiation divided by the color value before irradiation.

Based on the results of the calculation, the color retention of the coating can be assessed, usually using the following criteria to classify:

Color retention =1, indicating that the film completely maintains the primary color without color change.

Color retention 1, indicates that the color of the film has changed, and the smaller the value, the more serious the change.

The color retention of the film was measured by a color difference meter

Application field
The test of color retention has been widely used in various fields. For example, in the automotive industry, the color consistency of the coating film is crucial for quality control on the production line. In architectural decoration, it is necessary to ensure that the color of the wall coating remains bright for a long time to maintain the decorative effect. In addition, in the furniture manufacturing and electronic product manufacturing, color retention testing is also indispensable to ensure the stability and quality of the appearance of the product.

The color retention of the film is one of the key properties to ensure that the product retains its primary color under light exposure. In order to evaluate and ensure the color retention of the coating, the instrumental method of GB/T 9761 provides highly repeatable and accurate results. This detection method has a wide range of applications, helping manufacturers to provide high-quality products to meet consumer needs for color stability, while maintaining brand reputation and market competitiveness. Therefore, the research and detection of color retention is of great significance in the field of coating inspection