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Why Coeff icient of Friction testing is critical to packaging performance
In flexible packaging, the diff erence between a product that performs flawlessly on a high-speed filling line and one that causes costly stoppages can come down to a single measurement: Coeff icient of Friction (COF).
C
OF describes the resistance between two surfaces in contact — either as they begin to move (static COF) or as they continue moving against each other (kinetic COF). For quality, R&D, and operations experts working with fi lms, papers, foils and laminated fl exible materials, understanding and controlling these values isn’t optional. It is fundamental to packaging integrity and production effi ciency.
WHAT DOES COF ACTUALLY TELL YOU? When a fl exible material is too slippery, it can misfeed or fail to seal correctly. When it’s too grippy, it may jam on converting equipment or cause pouches or packaging stacks to stick together during fi lling, transport, or storage. Neither outcome is acceptable — in production or in the hands of the consumer.
COF measurement gives manufacturers the data they need to ensure fl exible materials behave predictably across every stage of the process: from winding and slitting to laminating, printing, form-fi ll-seal operations and fi nal packaging performance. It is also a key indicator of how surface treatments, coatings, slip additives and print processes have aff ected the base substrate, making it an essential tool in both production quality control and new material development.
Coeffi cient of friction testing is equally important for paper-based fl exible packaging, where friction characteristics infl uence sheet handling, stacking behaviour and converting effi ciency. Whether the material is a polymer fi lm, coated paper, foil laminate, or multi-layer structure, controlling friction helps ensure consistent processing and reliable packaging performance.
STANDARDS MATTER
COF testing is governed by internationally recognised standards, most commonly ASTM D1894 and ISO 8295, which defi ne the test method, specimen dimensions, sled weight and measurement speed. Adherence to these standards is critical not only for internal quality assurance but also for demonstrating compliance to brand owners and customers across global supply chains.
At Industrial Physics, supporting quality, R&D and operations experts to meet these standards, and to generate accurate, repeatable and reliable results, is at the heart of what we do.
GETTING THE TEST RIGHT
Accurate COF measurement depends on more than just the instrument. Factors including temperature, humidity, sample conditioning and surface cleanliness all infl uence results. This
is why test environment control and consistent sample preparation are just as important as the equipment itself. Our coeffi cient of friction testing solutions, including instruments from the TMI Büchel range, are designed to deliver the precision and repeatability that fl exible packaging producers demand. From entry-level bench-top models to advanced systems capable of handling a wide variety of fi lms, coated papers, foils and laminated substrates, our portfolio supports testing at every scale of operation.
THE ROLE OF COF IN SUSTAINABLE PACKAGING DEVELOPMENT
As the industry moves toward thinner gauges, recycled content, fi bre-based materials and alternative polymer structures, COF becomes an even more important parameter. New sustainable materials do not always behave like their conventional counterparts, slip characteristics can vary signifi cantly, and what works for a virgin polyethylene fi lm may not translate directly to recycled polymers, coated papers, or bio-based alternatives.
For R&D teams developing next-generation packaging, COF testing is a key tool in validating that new materials meet the processability and performance requirements of modern packaging lines, without compromising sustainability goals.
30
March 2026
www.convertermag.com
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