Fiberglass (FRP) doors and windows are internationally recognized as the fifth generation of such products; they are manufactured using a pultrusion process that combines medium-alkali glass fiber rovings (as reinforcement) with unsaturated resin (as the matrix) to create hollow profiles.
These products combine the structural robustness of aluminum alloys with the thermal insulation and corrosion resistance of PVC (plastic-steel) windows, while also offering a colorful, stylish, and aesthetically pleasing appearance. They do not expand in sunlight or contract in cold environments, require no internal metal reinforcement, and boast a service life of up to 50 years. Key technical specifications include a flexural strength of 388 MPa, wind pressure resistance of 5.3 kPa, a minimum heat transfer coefficient of 1.3 W/(m²·K), a linear expansion coefficient of 7.3 × 10⁻⁶/°C, a temperature tolerance range of -40°C to 200°C, and sound insulation of 39 dB. However, domestic development has been constrained by technical bottlenecks, including imperfect profile manufacturing processes, complex assembly procedures, and a susceptibility to damage during installation.
