PET Release Film Applications in Prepreg and Advanced Composite Manufacturing

Datatime: 10 Jan 2026 Visit: 23

As advanced composite materials continue to replace traditional metals in aerospace, marine, UAV, and sporting goods industries, auxiliary materials play a critical role in ensuring production quality and process efficiency. Among them, PET Release Film is an essential consumable widely used in prepreg processing, vacuum bagging, and composite curing applications.

This article explains what PET release film is, how it works in prepreg manufacturing, typical release force ranges, and its applications in carbon fiber parts such as boat paddles, drone propellers, and composite blades.

What Is PET Release Film?

PET Release Film is a polyester-based (PET) film coated with a specially formulated release layer that provides controlled and consistent separation between composite materials and tooling or auxiliary layers.

In composite manufacturing, PET release film prevents resin systems—such as epoxy, phenolic, or thermoplastic resins—from bonding to vacuum bags, breather fabrics, or mold surfaces during curing.

Key advantages of PET release film include:

Excellent dimensional and thermal stability
Precisely controlled release force
Clean peel-off with minimal residue
Compatibility with a wide range of resin systems
Availability in customized thicknesses and release levels
Typical Release Force Range of PET Release Film

Release force is a critical parameter when selecting PET release film. It is usually measured in grams per inch (g/in) and varies depending on coating formulation.

Release Type	Typical Release Force	Recommended Applications
Light Release	5–30 g/in	Fragile prepregs, automated processing
Medium Release	30–100 g/in	Standard carbon fiber prepreg systems
Heavy Release	>100 g/in	High-tack adhesives, special bonding For carbon fiber prepregs, medium to light release PET films are most commonly used, ensuring easy demolding without damaging fiber layers or cured surfaces.

How PET Release Film Is Used in Prepreg Manufacturing

PET release film plays multiple roles throughout the composite production process:

1. Prepreg Layer Protection

During prepreg production and storage, PET release film separates resin-impregnated fiber layers, preventing blocking and enabling easy handling.

2. Vacuum Bagging and Curing

In vacuum bag or autoclave curing, PET release film acts as a release interface between the laminate and auxiliary materials such as bleeder and breather fabrics.

3. Surface Finish Control

For visible composite surfaces—such as drone blades or marine paddles—PET release film helps achieve a smooth and uniform finish, reducing post-processing.

Applications in Advanced Composite Products

Carbon Fiber Boat Paddles and Marine Components

In marine applications, PET release film ensures consistent resin distribution, prevents resin leakage into vacuum layers, and improves demolding efficiency for long or curved components.

Drone Propellers and UAV Blades

High-performance UAV propellers require precise fiber alignment and surface quality. PET release film supports stable curing processes and helps achieve repeatable mechanical properties.

Composite Blades and Structural Parts

From sports equipment to industrial composite blades, PET release film improves manufacturing yield while maintaining surface integrity and dimensional accuracy.