Polypropylene (PP) is one of the five major general-purpose plastics, widely used in home appliances, automobiles, electronics, and other fields. Glass fiber reinforced heat-stabilized polypropylene, through the addition of glass fibers and heat stabilizers, significantly improves the material's mechanical strength and heat resistance, making it the preferred material for high-load structural components.
This material uses polypropylene as a matrix, incorporating 20%-30% glass fiber (the specific proportion varies depending on the grade) through a melt blending process to form a three-dimensional reinforcing network. The modulus of glass fiber can reach over 70 GPa, far exceeding PP's 1.5 GPa, effectively dispersing stress; the heat stabilizer, by capturing free radicals, inhibits degradation reactions during high-temperature processing (such as injection molding) or long-term use. A typical grade, such as PPH GBF 3020 RD H3, has a melt index of 12 cm³/10 min (230℃/2.16 kg), indicating moderate fluidity suitable for molding complex structural components.
After glass fiber reinforcement, the tensile strength of the material can be increased from 30 MPa in pure PP to 80-120 MPa, the flexural modulus from 1.2 GPa to 4-6 GPa, and the heat distortion temperature (0.45 MPa load) from 80℃ to over 150℃. These properties make it suitable for components that need to withstand mechanical stress and thermal environments, such as automotive bumper brackets, washing machine drums, and power tool housings. For example, after using this material in the inner drum of a certain brand of washing machine, its dimensional stability was more than 30% better than that of unreinforced PP during an 85℃ hot water washing cycle.
The material is supplied in granular form (25kg/bag) and requires injection molding. It is recommended to dry it to a moisture content ≤0.02% before processing to avoid hydrolysis and performance degradation. The injection temperature should be controlled at 220-250℃, and the mold temperature at 60-80℃. Excessive temperature may cause uneven glass fiber orientation or material degradation. Due to the presence of glass fiber, the mold runner needs to be optimized with a wide, rounded corner design to prevent fiber breakage; simultaneously, a screw and barrel with higher wear resistance are required to cope with the abrasive effects of the glass fiber.
Compared to traditional metals or unreinforced plastics, this material achieves a balance between lightweight and cost. Taking an automotive engine hood as an example, using glass fiber reinforced PP reduces weight by 40% and cost by 25%, and eliminates the need for subsequent electroplating or other surface treatments. Long-term usage tests show that within a temperature range of -40℃ to 120℃, the material's dimensional change rate is ≤0.5%, meeting the automotive industry's requirements for the coefficient of thermal expansion. Furthermore, the availability of natural and black colors reduces dyeing processes, further lowering production costs.