Extruded fiberglass board exposed to ultraviolet (UV) radiation for extended periods is prone to photo-oxidative degradation of its resin matrix, leading to surface darkening, decreased mechanical properties, and even microcrack propagation. This aging phenomenon not only affects the appearance of the spare tire cover but also weakens its structural strength and shortens its service life. To effectively delay UV-induced aging and fading, a multi-dimensional intervention is needed, encompassing material modification, surface protection, structural design, and environmental control.
Material formulation optimization is key to improving UV resistance. Adding UV-resistant additives, such as hindered amine light stabilizers (HALS) or UV absorbers (such as benzotriazoles), to the resin matrix can inhibit the initiation and propagation of photo-oxidative reactions. HALS terminates chain reactions by capturing free radicals, while UV absorbers convert UV energy into harmless heat; their synergistic effect significantly extends the material's service life. Furthermore, selecting resin systems with excellent weather resistance, such as vinyl ester resins or modified epoxy resins, whose aromatic or heterocyclic rings in their molecular structure enhance resistance to UV radiation and reduce degradation rates.
Surface coating protection is an effective means of directly blocking UV radiation. Coating the surface of the extended fiberglass board of the spare tire cover with an acrylic coating containing UV absorbers or a nano-SiO₂ reinforced coating forms a physical barrier, preventing UV rays from penetrating into the material. The nano-SiO₂ coating not only reflects UV rays but also reduces their penetration depth through scattering. Experiments show that after 2000 hours of QUV accelerated aging testing, the strength retention rate of the coated sample was 23% higher than that of the untreated sample. Furthermore, the coating must be hydrophobic to reduce the risk of coating peeling due to rainwater erosion.
Optimized structural design can reduce concentrated UV exposure in localized areas. Avoiding sharp angles or flat areas on the surface of the extended fiberglass board of the spare tire cover, and using rounded corners, reduces the angle of direct sunlight and lowers local strain levels. Simultaneously, drainage channels should be installed in areas prone to water accumulation to prevent long-term water retention from causing hydrolysis and further weakening material performance. For critical engineering applications, a layered structure can be introduced, using highly weather-resistant materials for the surface layer and low-cost materials for the inner layer, achieving a balance between performance and cost.
Environmental control during use is an important auxiliary measure to delay aging. When parking, prioritize shady spots or use a car cover to shield the vehicle from direct sunlight, avoiding prolonged direct exposure of the spare tire cover's extended fiberglass board to ultraviolet (UV) radiation. If the vehicle is parked outdoors for extended periods, periodically adjust the parking orientation to ensure even light exposure on the extended fiberglass board, reducing uneven aging. Furthermore, avoid using the spare tire cover in high-temperature environments, as high temperatures accelerate the thermal oxidation and degradation of the resin matrix, creating a synergistic aging effect with UV radiation.
Regular maintenance and inspection can detect early signs of aging and allow for remedial measures. Infrared thermal imaging or ultrasonic testing can identify delamination or microcracks within the extended fiberglass board of the spare tire cover, enabling timely resin injection repair and preventing defect expansion. For the surface coating, if peeling or fading occurs, recoating is necessary to maintain its protective effect. When cleaning the surface of the extended fiberglass board, avoid using alkaline or solvent-based cleaners to prevent corrosion of the coating or resin matrix.
The application of high-performance alternative materials provides new ideas for improving durability. Basalt fiber or carbon fiber hybrid structures can significantly enhance UV resistance within a cost-effective range. Their molecular structure stability is superior to traditional glass fiber, reducing the rate of photo-oxidative degradation. Furthermore, bio-based resins, such as castor oil-modified epoxy resin, not only possess excellent weather resistance but also reduce dependence on fossil resources, meeting sustainable development requirements.
UV aging protection for extruded fiberglass board needs to be addressed throughout its entire lifecycle, from material design and manufacturing to use and maintenance. Through comprehensive measures such as adding UV-resistant additives, surface coating protection, optimized structural design, controlled usage environment, regular maintenance and inspection, and the application of high-performance materials, the aging and fading process can be significantly slowed, extending service life and ensuring that the board is in good condition for emergency use, guaranteeing travel safety.
