As a plastic film supplier who’s spent the last 12 years troubleshooting and perfecting film solutions for everything from agricultural mulch to food packaging, I’ve lost count of how many times a client has emailed me asking, “What’s the impact strength of your plastic films?” It’s one of those questions that sounds simple on the surface—but if you stop at a single number, you’re missing the entire story of why that strength matters, and how it will make or break your project. Plastic Film
Let’s start with the basics, because too many suppliers (and even some buyers) treat impact strength as a vague buzzword. In polymer science, impact strength measures a plastic film’s ability to resist sudden, forceful damage—think a sharp warehouse forklift pallet dropping onto a pallet of wrapped goods, a branch piercing through agricultural mulch on a windy day, or a consumer’s car keys tearing into a bread bag on the way home. It’s not the same as tensile strength, which is the ability to resist stretching; a film can stretch a lot (good tensile strength) but still tear easily (bad impact strength), and vice versa. For film suppliers like me, impact strength is make-or-break because a film that passes a tensile test but fails an impact test will end up costing you far more in waste, downtime, and lost product than one that’s calibrated for the forces it will actually face.
Now, why does this matter to you, the end user? Let’s use real scenarios I’ve seen with clients to put this in perspective. Last year, a small organic vegetable farmer came to us after his old mulch film was tearing within two weeks of installation. He’d bought the cheapest film he could find, and the 1 ft diameter branches from his orchard trees were puncturing it every time the wind picked up. The issue? His film’s dart impact strength (the industry standard for film impact, measured by the Dart Drop Test) was only 150 g, when he needed at least 350 g to resist punctures from branches and farm equipment. We swapped him to a linear low-density polyethylene (LLDPE) film with a dart impact strength of 420 g, and that season he reported only 7 punctures across his 12-acre plot—compared to 112 the year before. That’s not just a small win; it meant he harvested 12% more vegetables because he didn’t have to manually repair mulch holes or replace damaged film mid-growing season.
Another example: a craft brewery that wanted to wrap their 12-pack beer carriers for shipping. They initially used a low-density polyethylene (LDPE) film, which is cheap but has a dart impact strength of only 180 g. During transit, 8% of their 12-packs ended up unwrapped, with labels torn off and bottles scuffed. After testing, we recommended a metallocene LLDPE (mLLDPE) film, which blends the flexibility of LDPE with the puncture resistance of LLDPE, hitting a dart impact strength of 510 g. The unwrap rate dropped to 0.2% within their first shipment, saving them an estimated $4,200 annually in lost product and rework costs. These aren’t abstract numbers—they’re the tangible results of choosing the right impact strength for your use case.
Here’s where a lot of suppliers drop the ball: we don’t just sell a single “impact strength” number for every film. Impact strength isn’t a one-size-fits-all metric; it changes based on the film’s composition, thickness, processing method, and even the temperature it’s used in. For example, a film’s impact strength drops dramatically in cold temperatures—use a standard LDPE film (200 g dart impact) for outdoor packaging in a Canadian winter, and it will become brittle, crack when squeezed, and tear at the slightest impact. Swap that to a low-temperature LLDPE, which has additives that keep its molecular chains flexible at -40°F, and the same film will still retain 85% of its impact strength in cold weather, compared to just 40% for LDPE. That’s a difference we’ve seen play out at a cold-storage warehouse client: they switched their packaging film last winter, and their damaged goods from impact dropped from 11% to 1.8% in three months.
Let’s get into the industry tests we rely on, because numbers mean nothing without context. The most common test for plastic film impact is the ASTM D1709 Dart Drop Test, where a weighted dart is dropped from a set height onto a 10×10 inch film sample. The weight of the dart that causes 50% of the samples to tear is the dart impact strength, measured in grams. Another test is the Elmendorf Tear Strength, which measures the force needed to propagate a tear once it’s started—critical for films that might get a small puncture and need to avoid tearing across the entire roll. For flexible packaging, especially for heavy goods, we also use the Falling Dart Impact Test (ASTM D4272), which simulates small, fast impacts like keys or small tools piercing a bag.
As a supplier, we tailor these numbers to exact customer needs. For a retail bag that only needs to carry a 5 lb bag of apples, a dart impact strength of 120 g is more than enough—using a higher number would be a waste of material and cost. For a industrial stretch wrap that needs to hold 2,000 lb pallets during long-haul shipping, we need a dart impact strength of at least 600 g, plus high Elmendorf tear strength, to resist forklift tines, road vibration, and debris. Last quarter, a construction supply company came to us needing film to protect concrete slabs from rain and dust during curing. Their old film would tear when walked on by workers, so we supplied a heavy-duty cross-linked polyethylene (XLPE) film with a dart impact strength of 720 g. It’s thicker than standard film, but not by much—1.5 mil vs. the standard 1 mil—and it cost them 18% less in waste because it didn’t tear, whereas their old film had to be replaced every 2-3 days at the job site.
I’ve also seen clients mistake high impact strength for a marker of “better” film, but that’s not true. A film with extremely high impact strength might be too stiff for its intended use. For example, a flexible food bag needs to bend when you pick it up, so an ultra-high-impact film would be rigid and hard to seal, leading to packaging leaks. That’s why we work with customers to balance impact strength with other properties: flexibility, sealability, UV resistance, clarity, whatever their project requires. It’s not about selling the strongest film; it’s about selling the right strength for their specific challenges.
Another common myth: “thicker film = higher impact strength.” While there’s a correlation, it’s not a linear one. A 2 mil LLDPE film might have a dart impact strength of 400 g, but a 2 mil mLLDPE film could have 550 g, because metallocene polymers have more uniform molecular chains that are better at absorbing impact. Thinner films can also have high impact strength if the polymer grade is optimized. Last year, we developed a 0.8 mil film for snack packaging that had a dart impact strength of 380 g—thinner than the standard 1 mil film used for that application, but with better impact resistance. That saved a snack manufacturer 12% in material costs, without increasing damage to their product during shipping.
Now, if you’re reading this as someone looking to specify plastic film for your next project, here’s what I want you to take away: don’t just ask “what’s the impact strength?” Ask, “what impact strength do I need for my application, and why?” Tell us your use case: is it for outdoor use in extreme temperatures? Will it be exposed to sharp objects? Does it need to wrap heavy pallets, or hold small consumer goods? As a supplier, we don’t just send you a spec sheet; we test samples of our films in conditions that match your project, so you know exactly how it will perform.
I’ve built my business on this kind of transparent, tailored service. For 12 years, I’ve worked side-by-side with farmers, packaging designers, construction managers, and small business owners to solve their film problems, not just sell them a product. Last month, a client who’s been with us for 7 years sent a note saying, “Your team didn’t just give me a film; you told me why my old one was failing and how this one will save me money.” That’s the impact of getting strength right—it’s not just about a number on a page, it’s about helping your customer succeed.
If you’re currently dealing with film damage, excess waste, or just want to make sure you’re using the right plastic film for your needs, we’re here to help. We’ll send free samples of our films, run the necessary impact tests to match your requirements, and work with you to find a solution that fits your budget. No hidden fees, no one-size-fits-all pitches—just the practical, science-backed advice we’ve learned over decades of working with plastic films.
Food Packaging Bags References:
ASTM D1709 – Standard Test Method for Impact Resistance of Plastic Film by the Dart Drop Method
ASTM D4272 – Standard Test Method for Total Energy Impact of Plastic Films by the Falling Dart Method
J. A. Brydson, “Plastic Materials”, 7th Edition, Butterworth-Heinemann, 1999
Polyethylene Film Properties and Applications, Society of Plastics Engineers (SPE), 2021
Huizhou Yangrui Printing & Packaging Co., Ltd.
Huizhou Yangrui Printing & Packaging Co., Ltd. is one of the top level plastic film manufacturers and suppliers in China, welcome to wholesale products from our professional factory. And if you are seeking for manufacturer printed plastic film wholesale business opportunities, please also feel free to contact us.
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