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Do you know the technology of TPE multiple injection moulding?
- Jan 04, 2019 -

Compound injection moulding can be used to enhance commodity functions, such as improving chemical resistance, enhancing grip, softer and more attractive feel.

Duplex injection moulding skills were first used to beautify the appearance of consumer goods and are now very popular. This skill is used in all kinds of applications, and can even be used to enhance the utility of commodities, such as improving chemical resistance, enhancing grip, feeling softer and more attractive.

Compound Injection Molding Skills: The commonly used material in Compound Injection Molding is Thermoplastic Elastomer (TPE). Varieties of materials for multiple injection moulding have been greatly added. Compound injection moulding is carried out on the base materials (such as ABS, PC, PC/ABS, PA and SAN). The TPEs used widely include SEBS, TPE-V, TPE-U, TPE-E and TPE-A.

The thermoplastic elastomer (TPE) is injected into the rigid base material compatible with the insert injection molding or the secondary injection molding. This makes "soft coated hard" goods more functional, such as insulation, chemical resistance, more ergonomically compatible, better handle, grip and cutting-edge aesthetic feeling.

Inlay Molding: In the process of inlay forming, rigid parts (usually hard plastic parts) are first made, then embedded in the cavity, and then TPE injection moulding is used on this component, and finally good commodities are obtained. Conventional injection moulding equipment can be used for insert moulding. Insertion of rigid components can be accomplished by manual or mechanical arms.

Second injection moulding: Second injection moulding is also called two injection moulding, two-color moulding or multi-material moulding. In this case, a dedicated machine with multiple barrels is used to write different data to the same die. The bonding between the solid base material and TPE is the key to the success of the processing. Poor cohesiveness can lead to doubts such as peeling, bending, wear or delamination. Compatibility between the two data and processing temperature are important factors affecting bond strength.

Material Compatibility: Bond Strength of Different Hard/Soft Material Combinations

Processing temperature: It reflects the relationship between TPE melting temperature, rigid substrate temperature and bonding strength. TPE is a thermoplastic elastomer (TPE-E or COPE) based on polyester, which is produced by DSM engineering plastics. This kind of polyester elastomer combines the strength, processing characteristics and thermosetting elastomer function of Engineering plastics, and improves the processing, yield and chemical resistance.

Most soft-touch injection moulding applications involve injecting a thin layer of soft material (TPE) onto a hard substrate. Because TPE generally needs to flow through a longer way and thin-walled area to fill the mold, TPE has a higher mobility. Low viscosity commodity specifications optimize the critical cohesiveness of compound injection moulding, which is the preferred information for this processing application.

Chemical bonding: TPE is bonded very well with polar polymers (such as PC, PC/ABS, ABS) used as rigid substrates by compound injection moulding. Because of this excellent cohesion, even when the torque is very large, it will not show its delamination with the substrate.

In the process of selecting the external elastomer, TPE has excellent layout characteristics and excellent appearance function, and links with TPE's outstanding processing function in compound injection moulding. Physical bonding or application of binders: Mechanical interlocking descriptions are often used to improve the bonding force between TPE and non-polar polymers (such as PP) or PA. In addition, bonding between flexible TPE and non-polar polymers can be improved by using binders or primers.