Aging Study of Automotive Sealing Strip Coating in a Simulated Sunlight Exposure Chamber
Automotive weatherstripping is a widely used rubber component in automobiles. During use and storage, it is susceptible to adverse environmental factors, especially ultraviolet radiation from sunlight, leading to surface cracking, blooming, chalking, and color changes. To investigate the changes caused by sunlight exposure, we designed the following test scheme for reference.
Automotive Weatherstripping Coating Light Aging Test:
Test Equipment:Huanyi Instruments, Sunlight Irradiation Simulation Chamber
Test Standard: PV1303
Sample Preparation: Clean the surface of the weatherstripping with alcohol, preheat it in a 200℃ oven for 3 minutes, then remove it and perform plasma treatment on the surface. Evenly spray the prepared coating onto the treated weatherstripping surface, bake it in a 200℃ oven, and cure for 3 minutes.
Test Content: Referring to SAIC Volkswagen's standard requirements for automotive weatherstripping TL 52704, the xenon lamp aging test for interior parts is conducted according to the PV 1303 standard, with a test cycle condition of PV1303/5 cycles.
Experimental Results: This study prepared six coatings with different aromatic PU/aliphatic PU ratios and compared their lightfastness to ambient light. A xenon lamp aging test was conducted using PV1303/5 cycles. The results are shown below.
As can be seen from the table, with decreasing aromatic PU content and increasing aliphatic PU content in the coatings, the grayscale level improved, and both the color difference AE(D65) and AE(F11) showed a decreasing trend, indicating that the lightfastness of the sealing strip surface improved.
Summary:
(1) As the content of aromatic PU in the coating decreases and the content of aliphatic PU increases, the grayscale level of the sealing strip coating after light aging improves, and the total color difference ΔE under the two light sources (D65/F11) gradually decreases. Therefore, the lightfastness of the part surface is better. However, the presence of benzene rings in the resin structure has an adverse effect on the aging resistance of the coating.
(2) As the molecular weight of polyurethane resin in the coating increases, the grayscale level of the sealing strip coating after light aging improves, and the total color difference ΔE under the two light sources (D65/F11) gradually decreases. Therefore, the larger the molecular weight of the resin, the better the lightfastness of the coating on the sealing strip surface.
The above is a study on the light aging of automotive sealing strip coatings. If you have any questions about the experiments, please consult the relevant technical personnel of Huanyi Instruments.