Sealing and welding properties of films, verification and comparison by laboratory sealing press

Production of sealing or welding seams on our laboratory sealing press (Kopp) and testing of the sealing seams with the Zwick tensile testing machine. The seals are made using previously agreed parameters. To create sealing curves individual parameters are varied, e.g. for determining the dependence of the sealing properties on the sealing temperature Ts [° C]. Of course, sealing curves can also determined depending on sealing pressure ps [N/cm] or sealing time ts [s]. Typically, a parameter is varied over 5 equal levels and the results are plotted graphically as a function of the variables (accredited test).

In short — AI-generated

This test determines the strength and integrity of sealing seams in flexible packaging by creating standardized seals on a laboratory press and pulling them apart using a tensile testing machine. We vary specific parameters such as sealing temperature, pressure, or dwell time to analyze how these factors influence the resulting seam quality.

The resulting data is visualized in sealing curves, which help identify the optimal processing window for a specific film material. In practice, this allows packaging developers to define reliable machine settings that ensure secure seals while maintaining consistent opening performance for the end user.

Text is AI-generated; based on test method data curated and verified by Innoform.

Test Method Group: Mechanical properties

Norms:

DIN EN 868-5- D (2019-03) Packaging for terminally sterilized medical devices – Part 5: Sealable pouches and reels of porous materials and plastic film construction – Requirements and test methods
DIN 55543-3 (06-2010) Verpackungsprüfung – Prüfverfahren für Verpackungsfolien – Teil 3: Bestimmung der Festigkeit von Längsnähten an Säcken und Beuteln
DIN 55409-1 (2012-09) Packaging – Test method for determining opening forces for peelable packagings – Part 1: Flexible packagings
DIN EN ISO 527-3 (2019-02) Plastics - Determination of tensile properties - Part 3: Text conditions for films and sheets
GKV Blatt I- IV (2018-08) Testing and evaluation clause for polyethylene films and products thereof
ASTM F 88/ F 88M (2023) Standard Test Method for Seal Strength of Flexible Barrier Materials
DIN 55529 (2012-09) Packaging – Determining the sealed-seam strength of sealings made of flexible packaging material
DIN 55409-2 (2013-10) Packaging – Test method for determining opening forces for peelable packagings – Part 2: Dimensionally stable packagings

Required Sample Amount: approx. 1 m² or 15 DIN A 4 sheets, minimum sample width 100 mm, optimum: film samples over total material width, e.g. approx. 2 linear metres with 0.5 m film width

Standard Tests

sealing graph (as a function of temperature)

Specific Norm: DIN 55529

Preparing of laboratory sealing by variation of the sealing temperature, sealing pressure and sealing time are held constantly. The seal strength is plotted as a function of the chosen parameter.

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sealing curve, variation of sealing pressure

Specific Norm: DIN 55529

Preparing of laboratory sealings by variation of the sealing pressure, sealing temperature and sealing time are held constantly. The seal strength is plotted as a function of the chosen parameter.

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sealing graph (as a function of sealing time)

Specific Norm: DIN 55529

Preparing of laboratory sealings by variation of the sealing time, sealing pressure and sealing temperature are held constantly. The seal strength is plotted as a function of the chosen parameter.

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sealing test with fixed parameter setting

Specific Norm: DIN 55529

One seal sample with fixed parameter setting for sealing pressure, temperature and sealing time is prapared. The seal strength of the sample is determined. This test is useable for for checking fixed specification requirements.

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