ASTM D904 is a standard practice that provides guidance for exposing adhesive samples to artificial light to assess their photostability. The standard specifies test conditions, including light source, exposure cycle and evaluation criteria, as well as test sample preparation and test procedures.
The purpose of this standard is to provide a uniform and reliable method for evaluating the photostability of adhesives, which is important for a variety of applications, including product development, quality control, and material selection. The standard also helps ensure consistency and reproducibility of test results across laboratories and studies.
The test method described in ASTM D904 uses a xenon arc light source to simulate the effect of natural sunlight on bonded specimens by exposing the specimens to cycles of light and dark, with light intensity and exposure time varying according to the intended application of the adhesive. After exposure, the specimens were evaluated for changes in physical properties such as color, hardness, and bond strength.
The standard also specifies the parameters of the light source, including spectral power distribution, irradiance and temperature control. Exposure cycles can be customized based on the intended application of the adhesive and the expected exposure duration under actual conditions. The standard recommends the use of control samples to monitor the stability of the light source and ensure consistent exposure conditions across multiple test runs.
Evaluation of exposed adhesive coupons can include a variety of tests, depending on the particular property of interest. For example, color change can be assessed using a Spectrophotometer or Colorimeter, while bond strength can be measured using standard mechanical tests. The standard also provides guidance for reporting test results, including specific test conditions, test results, and any observations or comments about the test specimen or test method.
In summary, ASTM D904 is an important standard for evaluating the photostability of adhesives, ASTM D904 provides a valuable method for evaluating the photostability of adhesives, and provides guidance for test conditions, exposure periods and evaluation methods . By using this standard, manufacturers and users can make informed decisions about adhesive performance under real-world conditions, helping to ensure product quality and reliability.
