3-Side Sealed Pouches Explained

When it comes to flexible packaging, 3-side sealed pouches are one of the simplest yet most effective formats. They are economical to produce, very versatile in use, and straightforward in construction. In this article I’ll explain what they are, how the bags themselves are manufactured (not the product filling process), the common materials used, their typical applications, and why businesses choose them.

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1. What is a 3-Side Sealed Pouch?

A 3-side sealed pouch is a flat, flexible package sealed on three edges and open on one edge for filling. After filling, the open edge is sealed to make a fully closed bag. The design is common for single-serve items, samples, sachets, and many other applications where a compact, low-cost package is needed.

Key characteristics:

• Flat and compact (no bottom gusset).
• Easy and fast to produce in high volumes.
• Strong barrier options possible via laminates.
• Inexpensive in material and processing compared to more complex pouch types.

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2. How Are 3-Side Sealed Pouches Made?

(This section describes only the manufacturing of the empty 3-side sealed bags — it does NOT cover product filling/packaging.)

Making 3-side sealed pouches is a focused manufacturing flow: start with raw roll-stock films, turn them into laminated webs, print the graphics, slit to width, form and seal three sides, perform finishing (tear-notch, hang-hole, cut), inspect, and pack the empty pouches for shipment. Below I walk through each step in detail based on the methods I use and see in factories.

1) Raw material & roll stock selection

• Manufacturers begin by selecting the appropriate roll-stock materials. Typical rolls contain PET, BOPP, metallized films, aluminum foil, PA (nylon), EVOH or PE depending on barrier needs.
• Rolls are inspected for defects, checked for correct core size and wound tension, and conditioned (temperature/humidity) as needed.

2) Printing (outer layer graphics)

• The outer film (or outer lamination layer) is printed with brand artwork via rotogravure, flexographic, or increasingly digital presses for short runs.
• Printing considerations: color registration, ink drying, varnish or primer layers, and print quality inspections.
• After printing, the web must be fully dried/cured before lamination.

3) Lamination (building the multi-layer web)

• Lamination bonds multiple films into a single multi-layer structure that provides the required barrier, strength and sealability.
• Common lamination methods:
  • Solventless/Adhesive lamination — adhesive between layers, solvent-free options common.
  • Extrusion lamination — molten PE extruded between layers for strong bonds.
  • Thermal lamination — heat-activated film bonding for certain film types.
• Typical layered structure for a high-barrier 3-side pouch: (Outer printed PET / Aluminum foil / Nylon / Inner PE heat-seal layer).

4) Surface treatments & coatings (optional)

• Corona or plasma treatments improve ink/adhesive wetting on some films.
• Barrier coatings or metallization may be applied prior to lamination to enhance oxygen/light resistance.

5) Slitting & rewinding (web preparation)

• Wide laminated rolls are slit into narrower rolls sized to the pouch width using a slitter-rewinder.
• Precision here is critical: edge quality, tolerances and tension control ensure clean seals and consistent pouch dimensions later.

6) Pouch-making — forming & 3-side sealing

There are two common manufacturing approaches to produce empty 3-side sealed pouches (both do not include filling):

A. Two-web method (face-to-face sealing)

• Two webs (printed outer and inner or two identical webs) are aligned face-to-face.
• The three sides are sealed by hot-bar or continuous heat-seal bars:
  • Two longitudinal side seals and one bottom cross-seal (or two cross seals + one long seal depending on machine setup).
• After sealing the three sides, a rotary or straight knife cuts the pouches apart.
• This method is very stable for high-speed production and avoids folding.

B. Single-web fold method

• A single web is folded longitudinally (creating a folded edge) so that the fold becomes one sealed side.
• The other three open edges are sealed (two sides + one cross-seal) to form a pouch that is later cut.
• Folding is useful for some print layouts and smaller formats.

Sealing technologies used:

• Hot bar heat sealing — common for PE-based inner layers; uses temperature-controlled bars to create seals.
• Impulse sealing — quick, low-energy sealing useful for thin films.
• Ultrasonic sealing — for materials where heat may damage print or for special laminates.
• Continuous rotary sealing — used on high-speed pouch-making lines.

Typical pouch-making machine features:

• Servo-driven film transport for accurate registration.
• Adjustable heat/pressure zones for reliable seals.
• Rotary knife or guillotine cutter to separate bags at high speed.
• Indexing and registration control to align print with seals.

7) Cutting, notching and finishing

• After sealing three sides and cutting, finishing operations add features that buyers expect:
  • Tear notch (easy-open), usually added by a blade or punch at a defined position.
  • Hang hole or Euro-hole for retail displays.
  • Window die-cutting (if the design includes a transparent window) — often done prior to forming.
  • Edge trimming to remove flash or irregular material.

8) Quality control & testing (for empty pouches)

Before packing empty pouches, rigorous quality checks ensure they meet specs:

Common QC checks:

• Visual inspection — print quality, registration, color accuracy, growth/defects.
• Dimensional check — pouch width, length, and position of notch/hang-hole.
• Seal integrity tests — peel/seal strength tests (measured in N/cm) and burst/bubble tests on sealed pouches.
• Leak detection — vacuum or pressure-based leak tests on sample pouches.
• Thickness & layer checks — ensuring laminate thickness and layer uniformity.
• Functional checks — confirm notch placement, hole alignment, and correct cut.

I always recommend running statistical sampling (e.g., ISO-based sampling plans) during production to catch intermittent defects early.

9) Coding & traceability

• Date codes, batch numbers, or internal lot codes can be printed or stamped on the pouch web or on finished pouches. This is useful for traceability even for empty pouches.

10) Secondary packing of empty pouches

• Empty pouches are typically stacked, counted, and packed into poly-bags or cartons for shipment to the filler or brand owner.
• For overseas shipments, pallets are stretch-wrapped and often shrink-wrapped inner packs to reduce moisture ingress.

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Pouch-Making Process Summary (Table)

Stage	Key machines	Purpose
Raw roll inspection	Unwinder, inspection table	Verify roll quality
Printing	Rotogravure/Flexo/Digital press	Apply graphics
Lamination	Laminator (adhesive/extrusion)	Build multi-layer web
Slitting	Slitter-rewinder	Cut to web width
Pouch forming & sealing	Pouch-making machine (hot-bar/rotary)	Seal 3 sides & cut
Finishing	Notch/hole punch, die-cutters	Add tear notch, hang hole
QC Testing	Burst/seal testers, visual inspection	Ensure integrity
Packing	Counting & cartoning line	Pack empty pouches

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Process considerations & common issues

• Temperature & tension control: Maintains consistent seals and avoids wrinkles.
• Static & dust control: Cleanroom-level controls may be needed for sensitive products later filled into these bags.
• Sealability mapping: When using complex laminates, validate heat/pressure/time settings to ensure consistent seals across machine speeds.
• Registration accuracy: Especially important for printed pouches so seals and cuts don’t misalign with artwork.
• Material compatibility: Some adhesives or sealant layers require specific heat/pressure profiles.

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3. What Materials Are Usually Used for 3-Side Sealed Pouches

(内容同前：列出 PET、PE、AL foil、PA、EVOH、可降解膜，并用表格说明功能与常见用途。)

Material	Function
PET (Polyester)	Printability and strength
PE (Polyethylene)	Food-contact, heat seal
PA (Nylon)	Puncture resistance
Aluminum Foil	High oxygen/light barrier
EVOH	Superior gas barrier (transparent)
Compostable films (PLA, PHA)	Biodegradable options

4. What Are 3-Side Sealed Pouches Used For?

The applications of 3-side sealed pouches span across food, healthcare, cosmetics, and industrial products.

Food Industry

• Coffee, tea, and snack samples.
• Instant soup or sauce sachets.
• Seasonings, sugar, or salt.

Medical and Pharmaceutical

• Alcohol prep pads.
• Diagnostic test kits.
• Unit-dose tablets and powders.

Cosmetics and Personal Care

• Lotion and shampoo samples.
• Facial masks.
• Travel-size creams.

Industrial Uses

• Chemical powders.
• Lubricant or adhesive samples.
• Agricultural seeds.

📌 The biggest advantage is single-use convenience, which makes them ideal for sampling, travel packs, and portion-controlled products.

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5. Why Businesses Choose 3-Side Sealed Pouches Over Other Options

Businesses often compare 3-side sealed pouches with stand-up pouches, flat-bottom bags, and bottles.

Advantages

• Low cost – Uses less material.
• Efficient storage – Flat design saves space.
• Tamper-evident – Consumers trust sealed packets.
• Great for samples – Perfect for trial packs and giveaways.
• Flexible printing options – Full-surface branding.

Comparison Table

Feature	3-Side Sealed Pouch	Stand-Up Pouch	Rigid Bottle
Cost	Low	Medium	High
Storage	Flat, compact	Upright, more space	Bulky
Barrier	Excellent	Excellent	Good
Eco-Friendliness	Moderate to High	High	Low
Best For	Samples, small packs	Retail food & liquids	Beverages, detergents

Real-World Example

A skincare brand switched to 3-side sealed sachets for their trial lotions. This reduced their packaging cost by 40%, allowed them to distribute more free samples, and ultimately boosted customer conversions.

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FAQ: 3-Side Sealed Pouches

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Conclusion

3-side sealed pouches are an essential packaging format for industries that value simplicity, cost savings, and product safety. They remain a top choice for samples, small retail packs, and single-use products, offering both manufacturers and consumers a balance of practicality and branding potential.

As sustainable materials become more accessible, we can expect to see even more brands embracing eco-friendly 3-side sealed pouches as a smarter packaging solution.