Two-color injection molding

TPE two-color injection molding is a common composite molding process in the rubber and plastic industry. It uses two-color injection molding equipment to integrally mold TPE soft rubber with hard plastics such as PP, ABS, PC, and PA, and is widely used in tool handles, electronic accessories, daily-use products, and security accessories. This process abandons traditional bonding and assembly methods, achieving soft-hard cladding, two-color layering, anti-slip sealing, and other effects, effectively improving overall product quality and production efficiency.

Its molding process relies on a dual injection system completed in steps: first, the hard plastic substrate is injected, and after the substrate is initially set, molten TPE material is injected a second time to clad or embed onto the surface of the hard rubber matrix. Thanks to TPE's excellent adhesion compatibility, soft and hard materials can bond tightly without adhesive, with minimal risk of delamination or detachment defects. Raw material pretreatment is required before processing: TPU materials need thorough dehumidification and drying, while conventional SEBS and SBS-based TPEs require moisture control and impurity removal to prevent quality issues such as bubbles and color spots in finished products.

Compared with ordinary single-color injection molding, TPE two-color injection molding demands higher process precision, requiring precise matching of molding temperatures, injection pressures, and cooling cycles for soft and hard materials to avoid issues such as material degradation, uneven stress, and incomplete cladding. The molded products combine the rigid support of hard plastics with the flexibility, anti-slip, wear resistance, and high resilience of TPE, offering excellent feel and sealing performance. This process features simplified steps, requires no vulcanization, and allows recycling of trimmings, making it environmentally friendly with a high yield rate, suitable for mass production of complex, aesthetically refined composite rubber and plastic products.