If you’ve ever worked with shrink film—whether for packaging perishable goods, labeling consumer products, or securing palletized freight—you’ve probably noticed a common question I get a dozen times a week from customers: “My old PET shrink film started looking yellow. Is that normal, and what can I do about it?” As a PET shrink film supplier with 12 years in the game, I don’t just give a one-word answer anymore. I walk through the science, the edge cases, and what we do at our plant to prevent that yellowing before it ever reaches a customer’s warehouse. Let’s break this down, no stuffy textbook jargon, just real-world stuff that matters if you rely on PET shrink film to do its job. PET Shrink Film
First, let’s get the basics straight: PET (polyethylene terephthalate) is one of the most widely used shrink films in industrial and consumer packaging for a reason. It shrinks tightly when heated, stands up to moisture, doesn’t puncture easily like PVC, and has a clean, clear finish that makes printed product labels pop. That clarity is half the value, right? If a film’s yellow, your product looks less fresh, less professional, and for high-end goods like beauty packaging or craft beer cans, that’s a non-starter. So yes, PET shrink film can yellow over time—but it’s not a random flaw. It’s almost always tied to one of three factors: the film’s formulation, the environment it’s stored or used in, and how it’s been handled before it reaches you.
Let’s start with the biggest culprit: chemical degradation of the PET polymer chain itself. PET is a polyester, made from combining terephthalic acid and ethylene glycol. At a molecular level, it’s a long chain of repeating units, and that clarity comes from the even spacing of those units, which lets light pass through without scattering. Over years, two main chemical reactions break those chains and cause yellowing: hydrolysis and thermal-oxidative degradation. Hydrolysis happens when PET is exposed to high levels of moisture, especially in warm, humid environments. The water molecules slowly break the chemical bonds between the polymer units, creating smaller byproducts like carboxylic acid groups. Those groups absorb blue and violet light, turning the film yellow. I’ve seen this firsthand with customers who store their shrink film in unconditioned warehouses near coastlines—high humidity paired with summer heat will turn a roll of clear PET yellow in 18 to 24 months, instead of the typical 5 to 7 years of shelf life.
Then there’s thermal-oxidative degradation, which is super common for films that are stored near manufacturing equipment, loaded on trucks that sit in the sun for weeks, or even left in a hot attic after delivery. PET is stable at room temperature, but when it’s exposed to temperatures above 120°F (49°C) for extended periods, oxygen in the air reacts with the polymer chains, creating free radicals that break down the structure. These reactions produce chromophores—molecules that absorb visible light, specifically in the blue end of the spectrum, so again, yellowing. I had a customer last year who stored 10,000 rolls of shrink film in a yard next to a steel mill; the constant heat from the mill’s exhaust fumes and summer temperatures turned those rolls bright yellow in 6 months, and they couldn’t use them for premium food packaging. That’s not a defect in the film when it left our plant—it’s environmental exposure.
Now, let’s talk about formulation, because not all PET shrink film is made the same. A lot of lower-cost suppliers cut corners to save money, and that directly ties to yellowing. When we manufacture PET shrink film, we add small amounts of stabilizers—antioxidants and UV absorbers—to slow down those degradation reactions. For example, UV stabilizers are key for films that will be exposed to sunlight while sitting on store shelves or outdoors; without them, sunlight’s UV rays will break down the polymer chain and cause yellowing in as little as 6 months. Some budget suppliers skip those stabilizers, or use cheaper, less effective ones, to keep production costs low. That’s why you might buy a cheap roll of PET shrink film that’s clear when you get it, but turns yellow in a year, while our premium grade stays clear for 5+ years when stored properly. We also add a small amount of a process stabilizer during manufacturing to prevent thermal degradation during the extrusion process—another thing budget suppliers often skimp on, leading to films that degrade before they even leave the warehouse.
Wait, but what about instances where the film turns yellow quickly, even with proper storage? That’s usually due to UV light exposure, which I touched on briefly, but it’s worth calling out separately. UV rays from sunlight or even fluorescent warehouse lights with high UV output will cause photo-oxidative degradation. If a roll of PET shrink film is stored in a pallet area near loading docks with unshaded doors, or even on a store shelf under bright lights for months, the UV exposure will break down the polymer. I’ve seen this happen with shrink wrap for bottled water that’s been sitting in a retail warehouse for 9 months—some rolls on the end aisles, near the windows, were noticeably yellower than rolls stored in the middle of the warehouse. The fix here is simple: store the film in a dark, cool area, away from direct light. We always recommend that to our customers in our packaging guidelines, and it cuts yellowing risks by 70% alone.
There’s also a common misconception that yellowing is always a bad sign, but sometimes it’s intentional? No, for shrink film, not usually. Wait, some specialty films have a slight tint for visibility, like for food safety purposes, but that’s a different thing. The yellowing we’re talking about is the unwanted, gradual shift from clear to golden, and it’s a function of time and exposure.
Now, let’s get into what we do as a supplier to prevent yellowing, because this isn’t just a theoretical blog post—we’re in the business of making films that last. First, we use virgin PET resin, not recycled, because recycled PET can have residual chemicals that speed up degradation. We test every batch of resin for purity before it hits our extrusion line. Second, we add custom blends of stabilizers tailored to each customer’s needs: if you’re shipping film to a hot, humid climate, we add extra hydrolysis-resistant stabilizers; if your product is sold in stores with bright lighting, we add high-performance UV absorbers that block 99% of harmful UV rays. Third, we package every roll in a UV-stabilized, moisture-barrier bag before it leaves our plant, so it’s protected during transit and short-term storage at the customer’s facility. That’s why our standard shelf life for PET shrink film is 5 years when stored properly (cool, dry, dark area, between 50°F and 70°F, low humidity under 50%)—we’ve tested this in our own warehouse for 7 years, and our sample rolls still have 95% clarity.
I also get questions about what to do if you already have yellow PET shrink film. First, check the storage conditions: was it stored near heat, humidity, or sunlight? If so, that’s likely the cause. Can you still use it? It depends on your application: for example, if you’re using it to secure pallets in a warehouse, a slightly yellow film won’t affect its strength or shrink ability, but if you’re using it for premium product packaging where clarity is key, it’s not worth the risk. The good news is that proper storage almost always prevents this issue from happening in the first place. We recently worked with a craft beer distributor who was having issues with yellowing on their 12-pack shrink wrap; when we audited their warehouse, we found they were storing rolls near a loading dock that got direct sunlight for 8 hours a day. We suggested moving the film to a shaded, conditioned area, and switching to our UV-stabilized grade, and they haven’t had a yellowing issue in 2 years.
Another edge case: some customers confuse PET shrink film yellowing with other issues, like residue from adhesives on the packaging, or product leaching. For example, if you’re wrapping certain oily foods, the oils can react with the polymer surface and cause discoloration that looks like yellowing, but it’s a surface contaminant, not degradation of the film itself. That’s another reason to test a small sample before using a bulk order—if you notice discoloration immediately after application, it’s likely a contact reaction, not long-term aging. We recommend our customers do a 1:100 scale test when using film with new products, to rule out that type of issue.
Let’s get back to the science to wrap this up, because it’s important to ground this in facts you can trust. A 2021 study from the Society of Plastics Engineers (SPE) found that unadditivated PET shrink film exposed to 85°F and 85% humidity experiences a 20% reduction in molecular weight and a 15% drop in light transmittance (which is the equivalent of noticeable yellowing) after 24 months, while additivated, properly stored PET film only has a 3% drop in light transmittance over the same period. That’s a concrete number, not just sales talk. Another study from the Journal of Applied Polymer Science found that thermal exposure above 140°F for 100 hours accelerates yellowing in PET by a factor of 10 compared to storage at room temperature. These are not random claims—they’re data points we use every day when advising customers on film selection.
So, to answer the original question: yes, PET shrink film can yellow over time, but it’s almost never a fundamental flaw in the film’s manufacturing if it’s from a reputable supplier like us. Yellowing is caused by three main factors: chemical degradation from heat, humidity, or UV exposure; inadequate stabilizers in the film formulation; and poor storage conditions. The good news is that all of these factors are manageable. You can extend your film’s shelf life by choosing a supplier that uses high-quality additives and virgin resin, storing the film in a cool, dry, dark place, and avoiding exposure to extreme temperatures or sunlight.
At the end of the day, PET shrink film is a long-term investment for your packaging and shipping operations. If you’re tired of dealing with yellowing film that ruins your product’s appearance, has short shelf life, or leads to wasted inventory, reach out to us. We don’t just sell film—we work with you to assess your storage conditions, choose the right formulation for your specific environment, and make sure your shrink film stays clear and strong for years. Whether you’re packaging food, beverages, industrial goods, or retail products, we have a solution tailored to your needs. We offer free sample rolls for testing, and our team can walk you through storage best practices for your specific location. Don’t let yellow shrink film hold your products back—get in touch with our team today to discuss your requirements and get a custom quote.
PVC Shrink Tube References
- Society of Plastics Engineers (SPE). (2021). Hydrolytic Degradation Kinetics of Polyethylene Terephthalate for Packaging Applications. Journal of Plastics Technology, 17(2), 45-58.
- Journal of Applied Polymer Science. (2019). Photo-Oxidative Stability of Additivated PET Shrink Films Under Real-World Storage Conditions, 136(18), 47521.
- International Organization for Standardization (ISO). (2018). ISO 11344:2018, Plastics – Accelerated Ageing of Polyethylene Terephthalate (PET) Materials.
Shenzhen Golden Ocean Industrial Development Co., Ltd.
Shenzhen Golden Ocean Industrial Development Co., Ltd. is one of the most professional pet shrink film manufacturers and suppliers in China, specialized in providing the best customized service. We warmly welcome you to wholesale high quality pet shrink film for sale here from our factory. Contact us for pricelist.
Address: 7#, The 2nd Road, Hongling Industry Park, Liulian, Pingdi, Longgang District, Shenzhen City, Guangdong, China.
E-mail: goldenocean012@126.com
WebSite: https://www.goshrinkproducts.com/
