Sachet Packaging: Types, Materials and Uses

A contaminated seal or misplaced tear notch can turn a single portion into a leaking sachet. A sachet is a small flat pouch, commonly with three sealed edges and a fold or with four sealed edges; choose the geometry around the dose, opening and filling equipment. This page covers the format; sachet film covers machine inputs.

Small packs leave limited space for filling and opening features. Confirm the finished seal layout and usable cavity on a drawing, then test filled samples.

Types of sachets

3-side seal sachets

One piece of film is folded in half, then sealed along two sides and the top once it is filled. The fold forms the fourth edge. This is one option for powders, liquids and creams. It needs only one web of film and gives a neat, flat pack.

4-side seal sachets

Front and back film faces are sealed together on all four edges; the web arrangement depends on the machine. This allows different materials on the front and back, for example a clear window on one side and a foil layer on the other. It is used where each side has a different job, or where cutting and sealing four edges gives a flatter pack or a square shape.

Shapes and tear features

Standard sachets are rectangular or square. Some have rounded or cut corners, shaped outlines or a patterned seal. Opening features include:

• A tear notch is a small cut in the side seal that starts a tear across the pack.
• A laser score is a line of weakness that lets the film tear in a controlled direction, which helps with tough or foil structures.
• A pour spout style opening is a cut corner that forms a spout when torn.

Tear performance depends on the film. The machine page, sachet film, has notes on how notches and film orientation affect opening.

Typical sachet materials

Separate polymer family from construction process. A mono-material design can be multilayer or laminated; it does not mean a single film layer. RecyClass’s March 2026 Design Book (v2.0) describes a mono-material laminated pouch. The following structures are candidates to evaluate, not application approvals.

Compare finished-structure barrier data at matching conditions; aluminum foil packaging explains foil structures. A mono-material laminate still needs barrier and sealing validation. The sealant must also resist the product, since oils, alcohol and surfactants can attack some layers.

For a recent paper-based liquid sample trial, the Kelpi and Bower material evidence checklist identifies the formulation, seam and destination questions left open by the announcement.

Design points that affect performance

Set seal width from pouch dimensions, structure, fill amount and equipment trials; there is no universal few-millimeter allowance. Keep product out of the sealing area through fill control and cleaning. A contamination-tolerant sealant still needs a defined contamination challenge and acceptance criteria.

ASTM F88/F88M-23 measures seal separation strength; ASTM F2096-11(2019) addresses gross leaks by internal pressurization. Choose methods suitable for the pack and agree limits before testing: strength alone does not establish absence of leaks.

Uses of sachets

• Condiments and food: ketchup, mayonnaise, sugar, salt, instant coffee and seasoning. Take-out and food service use them for portion control.
• Cosmetic and personal care samples: creams, serums, shampoos and perfumes handed out as trial sizes (cosmetic packaging).
• Pharmaceutical and health powders: single-dose powders, electrolytes and supplements (pharmaceutical flexible packaging).
• Household products: detergent, fabric softener and cleaning concentrates, often sold in small sachets in markets where a low price per purchase matters (household products packaging).

Why brands use sachets

• Single-dose control gives the user the right amount.
• Record unit cost for the specified structure and order rather than assuming a low cost.
• Sachets suit sampling and trial, since they are light and can be bundled with other products or magazines.
• The flat shape stores, ships and displays easily.
• The full surface can be printed.

On the other side, a sachet is single-use and not resealable, it generates more packaging per gram of product than a large pack, and recycling is difficult because of the small size and laminated layers. Check local collection and the rules in your destination market before making recyclability claims; recyclable flexible packaging has background.

Sachet vs stick pack

The narrow format is covered in stick pack packaging, and other small pack styles that use a fin seal in pillow bag packaging.

Choosing a sachet format

Use this filled-pack record with the first pouch order checklist. Record sample/lot ID, machine, settings, conditioning and the agreed acceptance limit for each check.

Keep the filling opening, notch and printed registration clear of the agreed seal area. Evaluate the seal after filling and handling, not just on a clean lab coupon.

Method and sources

The RecyClass Design Book, March 2026 (v2.0), page 39, supports the distinction between mono-material composition and lamination. The ASTM public scopes linked above distinguish strength from gross-leak testing. The sachet diagram is an editorial geometry schematic, not a supplier specification. Sources reviewed October 8, 2026; the table contains blank trial fields, not test results.