Flexible Packaging Wiki

A comprehensive guide on flexible packaging constructions and properties.

What is Flexible Packaging?

Flexible packaging is packaging whose container shape can change after the contents are filled or removed. It is made mainly from paper, aluminum foil, fibers, plastic films and their laminates, formed into bags, pouches and similar containers.

✨ Key Advantages

• Light weight, easy to ship
• Saves storage space
• Relatively low cost
• Highly customizable

🎯 Application Areas

• Food packaging
• Pharmaceutical packaging
• Household and personal care
• Agricultural produce packaging

📊 Market Trends

• Sustainable and eco-friendly
• Enhanced functionality
• Smart packaging
• Personalized customization

Common Flexible Packaging Materials

🔹 PE (Polyethylene)

The most widely used plastic film, with good moisture resistance, flexibility and heat sealability.

Properties:

Good moisture barrier, average clarity, poor oxygen barrier, low cost

Typical Uses:

Shopping bags, refuse sacks, food storage bags, frozen food packaging

Spec Range:

Thickness: 20-200 μm | Density: 0.91-0.96 g/cm³

🔹 PP (Polypropylene)

High clarity, good rigidity and strong heat resistance — widely used for food packaging.

Properties:

High clarity, good heat resistance (retortable), stiff, glossy

Typical Uses:

Biscuit wraps, confectionery, instant noodle packs, microwaveable food

Spec Range:

Thickness: 15-80 μm | Heat resistance: up to 121°C

🔹 PET (Polyester)

High mechanical strength, excellent clarity and gas barrier — the first choice for premium packaging.

Properties:

High strength, high clarity, good gas barrier, puncture- and grease-resistant

Typical Uses:

Retort pouch outer layer, vacuum packaging, coffee packaging, tea packaging

Spec Range:

Thickness: 12-50 μm | Heat resistance: up to 130°C

🔹 AL (Aluminum Foil)

Completely blocks light, oxygen and water vapor — the strongest barrier material.

Properties:

Total light/oxygen/moisture barrier, metallic sheen, heat resistant, opaque

Typical Uses:

Coffee, tea, pharmaceutical packaging, high-temperature retort pouches

Spec Range:

Thickness: 7-40 μm | Barrier: virtually 100%

🔹 Laminated Film

Combines different materials by dry, wet or co-extrusion lamination to pool their strengths.

Common Structures:

PET/PE, PET/AL/PE, BOPP/CPP, PA/PE

Typical Uses:

Puffed snacks, coffee, tea, vacuum packaging, retort pouches

Lamination Methods:

Dry lamination, wet lamination, extrusion lamination, co-extrusion

Flexible Packaging Structure Design

A Typical Three-Layer Structure

Outer Layer (Print Layer)

PET, BOPP, PA

Provides mechanical strength and printability

Middle Layer (Barrier Layer)

AL, EVOH, PA

Provides oxygen and water vapor barrier

Inner Layer (Sealant Layer)

PE, CPP

Provides heat sealability and food-contact safety

💧 Moisture Barrier Structure

PET/PE, BOPP/PE

For biscuits, confectionery, dried fruit and other moisture-sensitive products

🛡️ High Barrier Structure

PET/AL/PE, PET/EVOH/PE

For coffee, tea, nuts and other oxygen-sensitive products

🔥 Retort Structure

PET/AL/CPP, PA/AL/CPP

For meat and ready meals that require high-temperature sterilization

❄️ Frozen Food Structure

PA/PE, PET/PE

For quick-frozen foods, frozen meat and other cold-stored products

Flexible Packaging Processes

🖨️ Printing

• Gravure — fast, high quality, suits large runs
• Flexo — eco-friendly, low cost, suits small to medium runs
• Digital — small runs, personalization, proofing

🔗 Lamination

• Dry lamination — the most widely used, works with many materials
• Solventless lamination — eco-friendly, preferred for food packaging
• Extrusion lamination — low cost, suits simple structures

✂️ Pouch Making

• 3-side seal — the most common, low cost
• Back seal — clean sides, good for display
• Stand-up pouch — self-standing, premium look
• Zipper pouch — reclosable, highly convenient

🎨 Surface Treatment

• Metallizing — metallic sheen, high barrier
• Coating — functional coatings, an eco-friendly foil substitute
• Holographic lasering — anti-counterfeiting and visual effect

💡 How to Choose Flexible Packaging Materials

1. By product characteristics:

Oily products → choose grease-resistant PET or BOPP
Acidic products → avoid aluminum foil; choose PET or PA
Oxidation-prone products → choose a high-barrier structure (with AL or EVOH)
High moisture content → choose a moisture-resistant PE-based structure

2. By storage conditions:

Ambient storage → PET/PE or BOPP/PE is generally sufficient
Chilled and frozen → PA/PE or PET/PE, which resist cracking at low temperature
High-temperature retort → PET/AL/CPP or PA/AL/CPP, rated above 121°C

3. By cost budget:

Economy → PE monolayer, BOPP/PE ($0.8-1.5/m²)
Mid-range → PET/PE, BOPP/CPP ($1.5-3/m²)
Premium → PET/AL/PE, multilayer co-extrusion ($3-8/m²)

Factory Direct Custom Packaging & Prototypes

Need Production Quotes or Custom Sized Boxes?

TadaPack (www.tadapack.com) offers direct factory manufacturing for corrugated shipping cartons, mailer boxes, rigid gift boxes, and eco-friendly protective packaging with instant online quotes and free vector CAD dielines.

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