Release film is widely used in various industries such as electronic die-cutting, label backing, optical bonding, FPC lamination, protective film, etc. It is a "invisible assistant" for the processing of many adhesive materials. However, many companies often only focus on peel strength when purchasing or developing release films, neglecting a more fundamental selection factor - the substrate. The different substrate materials (such as PET, PE, BOPP, CPP, etc.) directly determine the mechanical properties, thermal stability, processing adaptability, and final use effect of the release film.

The substrate of release film is the "carrier" of all functions, and its thickness, strength, thermal stability, and flexibility directly affect the performance of the product in multiple processes such as die-cutting, lamination, bonding, and waste disposal.

PET substrate is leading in mechanical strength, thermal stability, and processing accuracy, and is currently the main material in the fields of electronic die-cutting and high-end module bonding. Although PE and CPP have weaker performance, they excel in low cost and good flexibility, making them suitable for non structural release films such as temporary protective films and simple labels. BOPP falls between the two and is widely used in the fields of labels and some functional films.

Different applications have varying performance requirements for release films, so it is necessary to determine the appropriate substrate based on the scenario. Here are several substrate matching suggestions for typical application scenarios:

① Electronic die-cutting and precision bonding

Recommended substrate: PET; Reason: Die cutting requires extremely high dimensional accuracy, thermal stability, and tension control. PET has extremely low thermal shrinkage and high strength, which can maintain good stiffness and flatness on high-speed die-cutting machines, ensuring cutting accuracy and smooth waste discharge.

② Label and Printing Industry

Recommended substrate: BOPP/PE; Reason: Label products usually require moderate die-cutting accuracy, with a focus on good printing performance and soft adhesion. BOPP has a smooth surface and high transparency, making it suitable for coating and printing; PE is soft and low-priced, suitable for a large number of disposable labels.

③ Optical bonding and OCA applications

Recommended substrate: High cleanliness PET; Reason: When used for OCA optical adhesive bonding, the release film needs to have extremely high surface cleanliness, no bubbles, no particles, and no residue or static interference after peeling. Ordinary PE and BOPP cannot meet such high standards.

④ Industrial protection and temporary protective film

Recommended substrate: PE/CPP; Reason: The temporary protective film used during transportation and packaging is mainly designed to prevent dust and scratches. Choosing soft and low-cost PE or CPP is more cost-effective.

⑤ Multi layer lamination and FPC cover film

Recommended substrate: PET (high temperature resistant); Reason: During the multi-layer lamination process, it is necessary to withstand a hot pressing environment above 150 ℃. Only PET substrate can maintain the same size and physical properties, ensuring the quality of interlayer lamination.

During high-speed die-cutting, PET ensures good synchronicity and stability due to its high stiffness and low ductility; However, due to its excessive softness, PE often experiences problems such as stretching, curling, and wrinkling, leading to machine misjudgment or cutting deviation. Although BOPP is not as precise as PET, its better surface properties and lower cost make it perform well in medium speed processes.