Do you know about the dual injection molding technology of TPE?

Repetitive injection molding can enhance the functionality of products, such as improving chemical resistance, enhancing grip, making the feel softer and more attractive.
Repetitive injection molding technology was initially used to beautify the appearance of consumer goods, and it is now quite popular. Various applications have adopted this technology, and it can even be used to enhance the functionality of products, such as improving chemical resistance, enhancing grip, making the feel softer and more attractive.
Repetitive injection molding technology: The commonly used materials in repetitive injection molding are thermoplastic elastomers (TPE). The varieties of materials applicable for repetitive injection molding have greatly increased. In the base materials (such as ABS, PC, PC/ABS, PA, and SAN), repetitive injection molding is carried out on the base materials, and TPEs such as SEBS, TPE-V, TPE-U, TPE-E, and TPE-A are commonly selected.

Whether using insert injection molding or secondary injection molding, the thermoplastic elastomers (TPE) are injected onto the compatible rigid base materials. This enables the enhancement of the functionality of "soft covering hard" products, such as insulation, chemical resistance, better ergonomic fit, better feel, grip, and outstanding aesthetic appeal.
Insert molding: In insert molding, a rigid component (generally a relatively hard plastic component) is first made and inserted into the mold cavity, then TPE is injected onto this component to obtain a complete product. Common injection molding equipment can be used for insert molding. The insertion of the rigid component can be completed manually or by mechanical arms.
Secondary injection molding: Secondary injection molding is also called double injection molding, two-color molding, or multi-material molding. In this case, a dedicated machine with multiple barrels is used to inject different materials into the same mold. The adhesion between the rigid base material and TPE is crucial for the success of the processing. Poor adhesion can lead to problems such as peeling, bending, wear, or delamination. Compatibility between the two materials and processing temperature are important factors affecting the adhesion strength.
Material compatibility: Adhesion strength of different hard/soft materials combinations
Processing temperature: It reflects the relationship between the melting temperature of TPE, the temperature of the rigid base material, and the adhesion strength. TPE is used in repetitive injection molding. Polyesters with TPE-E or COPE as the matrix are produced by DSM Engineering Plastics. These polyester elastomers have the strength, processing characteristics, and thermosetting elastomer functions of engineering plastics, improving processing, production rate, and chemical resistance.
Most soft repetitive injection molding applications involve injecting a thin layer of soft material (TPE) onto a hard base material. Because TPE generally needs to flow through a long path and thin-walled areas to fill the mold, it must have high fluidity. The low-viscosity product specifications optimize the adhesion crucial for repetitive injection molding, making it the preferred material for this application.
Chemical adhesion: TPE adheres very well to polar polymers (such as PC, PC/ABS, ABS) used as rigid base materials through repetitive injection molding. Due to this excellent adhesion, even under very high torque, there is no appearance of delamination between TPE and the base material.

 
During the selection of surface elastomers, the excellent layout characteristics and excellent surface sensory function of TPE, combined with the excellent processing function of repetitive injection molding, are the key factors for this application. Physical bonding or adhesive application: When repetitive injection molding is carried out between TPE and non-polar polymers (such as PP or PA), mechanical interlocking descriptions are often used to improve the bonding force with the base material. In addition, adhesives or primers can be used to improve the adhesion between soft TPE and non-polar polymers.