BOPP Film Basics

What is BOPP Film?

Both BOPP wet lamination film and pre-coated film are laminating materials used for surface finishing of paper prints, designed to enhance wear resistance, water resistance, stain resistance, color vibrancy, and texture. The key difference lies in the "adhesive application method".

1. BOPP Wet Lamination Film (Wet Lamination Film)

Also known as "thermal lamination film" or "wet coating lamination", wet lamination film applies adhesive (solvent-based or water-based) to the transparent BOPP film surface during the lamination process, then复合 with print materials through hot pressing rollers.

Process Flow

1. Adhesive Coating: Using the coating device on the laminator, specialized laminating adhesive (usually solvent-based or water-based) is evenly applied to the BOPP film surface.
2. Drying: The adhesive-coated film passes through a drying tunnel, where heat evaporates the solvent or water in the adhesive, making the adhesive layer tacky.
3. Thermal Press Bonding: The film and print material enter the composite section consisting of heated and pressure rollers. Under combined heat and pressure, the adhesive layer is activated, firmly bonding the film to the print surface.
4. Slitting and Rewinding: Laminated products are slit into sheets or rewound as needed.

Characteristics

Process: "Apply and laminate on the spot" - adhesive coating and lamination completed in one step on the laminator.

Certifications

• Relatively lower cost
• Slightly more tolerant of paper flatness requirements

Disadvantages

• Poor environmental performance (especially solvent adhesives, with VOC emissions and strong odors)
• Prone to bubbling and delamination (caused by incomplete adhesive drying and solvent evaporation)
• Prints may yellow due to solvent penetration, with poor long-term preservation
• Relatively lower production efficiency

Main Applications

Medium-to-low grade printed materials with high requirements for short-term display effects and cost control, but low requirements for long-term preservation and environmental performance, such as promotional flyers, notebook covers, and textbooks.

2. BOPP Pre-coated Film (Pre-coating Film / Thermal Lamination Film)

Also known as "cold mounting film" or "dry coating lamination", pre-coated film refers to film that has already been coated with hot melt adhesive (EVA adhesive) or pressure-sensitive adhesive by the manufacturer using professional equipment, and wound into finished rolls. Users no longer need to apply adhesive during lamination.

Process Flow

1. Pre-coating: Film manufacturers apply solid hot melt adhesive (EVA) or pressure-sensitive adhesive to the BOPP base film on specialized coating lines.
2. Lamination: Users install the pre-coated film rolls on the laminator.
3. Activation and Bonding: Film and prints pass through heated and pressure rollers together. Heat melts the pre-coated adhesive layer, while pressure ensures tight contact with the print. The entire process requires no liquid adhesive or drying stage.
4. Slitting and Rewinding: Similar to wet lamination process.

Characteristics

Process: "Hot press and bond immediately" - no adhesive application needed during lamination.

Certifications

• Environmentally friendly (no solvent emissions, no odor)
• Stable lamination quality, no bubbling or delamination
• Excellent color preservation, long-term fade and yellowing resistance
• Easy operation, high production efficiency

Disadvantages

• Relatively higher cost
• Stricter requirements for paper flatness and laminator temperature control

However, since the pre-coating process adds extra manufacturing steps, the unit price of pre-coated film is higher than BOPP base film. But considering its high efficiency, low defect rate, and no adhesive costs, the overall cost may be more advantageous in large-scale production.

Main Applications

Medium-to-high grade printed materials with high requirements for quality, environmental performance, and durability, such as premium photo albums, high-end book covers, gift packaging, cosmetics/food packaging boxes, and long-term document preservation.

Wet vs. Pre-coated Film Comparison

Aspect	Wet Lamination Film	Pre-coated Film
Adhesive Application	On-site adhesive application (solvent or water-based)	Pre-applied hot melt adhesive (EVA)
Process Feature	Apply and laminate, requires drying	Hot press and bond, no drying needed
Environmental	Poor (VOC emissions)	Excellent (solvent-free)
Lamination Quality	Prone to bubbling, delamination	Stable, no bubbling or delamination
Preservation	Poor (prone to yellowing)	Excellent (fade-resistant)
Production Cost	Lower (adhesive cost low)	Higher (material cost high)
Production Efficiency	Relatively lower	High
Application	Medium-to-low grade prints	Medium-to-high grade prints

Key Questions for BOPP Film Selection

Primed vs. Unprimed Explanation

Primed: First coat with water-based adhesive, then coat with EVA. Advantages: Cost-saving. Disadvantages: Film turns yellow.

Unprimed: Direct EVA coating.