{"id":3443,"date":"2026-09-23T11:53:37","date_gmt":"2026-09-23T03:53:37","guid":{"rendered":"http:\/\/www.amirzajavab.com\/blog\/?p=3443"},"modified":"2026-09-23T11:53:37","modified_gmt":"2026-09-23T03:53:37","slug":"what-is-the-coefficient-of-friction-of-pvc-shrink-film-4b07-127a45","status":"publish","type":"post","link":"http:\/\/www.amirzajavab.com\/blog\/2026\/09\/23\/what-is-the-coefficient-of-friction-of-pvc-shrink-film-4b07-127a45\/","title":{"rendered":"What is the coefficient of friction of PVC shrink film?"},"content":{"rendered":"

When I first started in the PVC shrink film supply business 12 years ago, I used to get the same question from every new client in the packaging space\u2014from small craft brewers looking to label their cans to large industrial clients wrapping pallets of automotive parts: \u201cWhat\u2019s the coefficient of friction of your PVC shrink film?\u201d Back then, I\u2019d stumble a little answering, because it wasn\u2019t a one-size-fits-all number. Today, after testing thousands of rolls for different use cases, walking clients through on-floor applications, and learning how subtle material tweaks change that number, I can break this down like I\u2019m chatting with a fellow business owner who needs packaging that actually works. PVC Shrink Film<\/a><\/p>\n

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Let\u2019s start with the basics that matter for anyone handling PVC shrink film, whether you\u2019re running a packaging line or stacking wrapped goods in a warehouse. The coefficient of friction (COF) measures how easily two surfaces slide against each other. For packaging films, we split this into two key types: static COF, which is the force needed to start two surfaces moving relative to each other, and kinetic COF, the force needed to keep them sliding once they\u2019re moving. Static COF is the big one for most operations\u2014if your film has too high a static COF, two rolls of your shrink film will stick together; if it\u2019s too low, pallets of wrapped products will slide off forklift forks mid-transit.<\/p>\n

My clients will often guess the COF is just a generic stat printed on a spec sheet, but that\u2019s where they miss the mark. PVC shrink film is a custom product, so its COF shifts based on four main factors: the resin blend we use, any additives we put in to adjust slip properties, how the film is manufactured (cast vs. blown, processing temperature), and even the surface it\u2019s sliding against. For context, standard PVC shrink film we supply for general packaging has a static COF of 0.25 to 0.4 when sliding against steel, and 0.3 to 0.5 when sliding against corrugated cardboard. That range isn\u2019t random\u2014it\u2019s the sweet spot for most clients\u2019 needs.<\/p>\n

I want to ground this in real client work I did last year, because that\u2019s where this stuff stops being a textbook term and starts being a solution. A mid-sized dairy processor came to me panicking because their existing PVC shrink film was causing constant jams on their automatic case packing lines. Their line would stop 10 to 15 times a shift, costing them 20 hours of downtime a week and thousands in lost production. The spec sheet their old supplier gave them listed a COF of 0.3, but when we tested the film in our in-house lab, we found the static COF was actually 0.55\u2014way higher than the advertised number.<\/p>\n

What was the issue? The old supplier cut corners on slip additives. They used a cheap, short-chain slip agent that wears off within a few days of the film being unwound from the roll. Once that agent was gone, the bare PVC surface rubbed against the metal conveyor tracks, creating enough friction to stall the line. We swapped them our standard food-grade PVC shrink film, which uses a heat-stable, long-chain slip additive that\u2019s infused evenly throughout the film during extrusion, not just coated on the surface. We tested the new film\u2019s COF over 30 days: initial static COF was 0.32, and after 30 days of being rolled and unrolled on their line, it only crept up to 0.37. Their line downtime dropped to less than 15 minutes a week\u2014they still mention that job in our monthly check-ins.<\/p>\n

Another common misconception is that lower COF is always better. That\u2019s not true, and I learned that the hard way with a client wrapping heavy construction materials. A roofing manufacturer approached me because their previous film was sliding off the pallets they were shipping via flatbed truck. They\u2019d ordered film with a COF of 0.18, thinking \u201cslipperyer is better.\u201d But during a test shipment on a wet highway, the shrink film around their pallets shifted, so that when the driver slammed on brakes, three pallets of shingles slid into each other, causing $12,000 in damage. We adjusted their PVC film\u2019s COF to 0.42 for pallet wrapping\u2014high enough to hold the load tight during transport, but low enough that it fed smoothly through their shrink tunnels and wrapping machines. That job taught me: COF has to match your specific application, not a generic ideal.<\/p>\n

Now, let\u2019s talk about how we measure COF in our facility, because that\u2019s the reason our numbers are trusted by clients across North America. We use ASTM D1894, the standard test method for static and kinetic COF of plastic films and sheeting. Here\u2019s what that means for our process: we cut two 6×6 inch samples of film, tape one sample to a flat steel plate, attach the other sample to a 200 gram sliding weight, then pull the weight across the steel at 5 inches per minute while a gauge measures the force needed. We run three tests per sample, then average the results to eliminate variability. For every roll of PVC shrink film we ship, we include a COF test certificate\u2014no fine print, no hidden surprises.<\/p>\n

What factors can change COF after the film leaves our warehouse? A lot, and it\u2019s important to manage expectations there. Temperature and humidity are big ones. If our film is stored in a hot, humid warehouse, the slip additives start to migrate too quickly, making the COF lower than our test number. Conversely, if it\u2019s stored in a cold, dry space, the additives stay on the surface longer, but the static COF can get a little higher. We always include storage instructions with every delivery: keep film at 60 to 75 degrees Fahrenheit, relative humidity 40 to 50 percent, and store rolls on their sides, not standing up, to prevent the inner layers from sticking together.<\/p>\n

For specialty use cases, we can adjust COF to almost any number our clients need. Let\u2019s break down common customizations:<\/p>\n