{"id":3608,"date":"2026-11-03T19:59:43","date_gmt":"2026-11-03T11:59:43","guid":{"rendered":"http:\/\/www.almizhariya.com\/blog\/?p=3608"},"modified":"2026-11-03T19:59:43","modified_gmt":"2026-11-03T11:59:43","slug":"what-is-the-moisture-resistance-of-blown-stretch-film-4f2e-f8a677","status":"publish","type":"post","link":"http:\/\/www.almizhariya.com\/blog\/2026\/11\/03\/what-is-the-moisture-resistance-of-blown-stretch-film-4f2e-f8a677\/","title":{"rendered":"What is the moisture resistance of blown stretch film?"},"content":{"rendered":"

What\u2019s the moisture resistance of blown stretch film, and why does it matter for your shipments? Let\u2019s be real\u2014if you\u2019re shipping goods, especially ones that can get ruined by dampness, that stretch wrap you\u2019re using isn\u2019t just a \u201cwrap-it-and-go\u201d kind of thing. I\u2019ve been in the blown stretch film game for over 12 years now, and I can\u2019t tell you how many times a customer has called me panicking because their pallet of electronics parts, food-grade packaging, or raw materials showed up with water damage\u2014and half the time, it\u2019s because they didn\u2019t pay attention to their film\u2019s moisture resistance. So let\u2019s break this down like I\u2019d break it down for a new guy on the production line, no fancy jargon, just straight facts. Blown Stretch Film<\/a><\/p>\n

<\/p>\n

First off, what even is blown stretch film, vs. cast stretch film? I know a lot of people mix them up, but here\u2019s the quick version: blown film is made by extruding plastic resin through a round die, blowing air to bubble it up, then cooling it before stretching. That process gives it a different molecular structure than cast film (which is flat, cooled fast). That structure directly impacts moisture resistance\u2014so that\u2019s why the two types aren\u2019t interchangeable for jobs where damp is a risk.<\/p>\n

Now, moisture resistance isn\u2019t a \u201cone-size-fits-all\u201d number. You can\u2019t just say \u201cthis film is moisture resistant\u201d and be done with it. It\u2019s measured by something called water vapor transmission rate (WVTR), right? Yeah, WVTR is the amount of water vapor that passes through a material in a set amount of time, usually grams per square meter per 24 hours (g\/m\u00b2\/day). The lower the number, the less vapor gets through\u2014so the better the moisture resistance. But here\u2019s the thing: blown stretch film\u2019s WVTR isn\u2019t static. It changes based on the resin we use, the thickness of the film, and even the environmental conditions when you\u2019re using it.<\/p>\n

Let\u2019s talk resin first. Most blown stretch film is made with linear low-density polyethylene (LLDPE), but we mix in other resins sometimes\u2014like low-density polyethylene (LDPE) or even metallocene LLDPE (mLLDPE) to improve stretch. Wait, why does resin matter for moisture? Polyethylene itself is a pretty good barrier to moisture, but not perfect. If you use a pure LLDPE blend, our standard 80-gauge blown film has a WVTR around 5-7 g\/m\u00b2\/day. But if we add a bit more LDPE (which is a bit more flexible, but still has similar barrier properties), we can tweak that to 4-6 g\/m\u00b2\/day. Now, if you need way better moisture resistance\u2014like for shipping agricultural goods that need to stay dry in a rainy warehouse, or bulk chemicals that can\u2019t absorb moisture\u2014we can go with a co-extruded blown film. That\u2019s when we layer different resins: the core layer is for strength, and the outer layers are made with a slightly modified PE that\u2019s a tighter barrier. Those co-ex films have a WVTR closer to 2-4 g\/m\u00b2\/day. That\u2019s a big difference, right?<\/p>\n

Then there\u2019s thickness. This is a huge one I see customers sleep on. Thicker film = better moisture resistance, mostly. A 60-gauge blown film (that\u2019s 15 microns, for anyone who uses microns) will have a higher WVTR than a 100-gauge (25 microns) film of the same resin blend. Wait, let\u2019s make that relatable: if you\u2019re wrapping a pallet of furniture for storage, a thin 60-gauge might be fine for a week or two, but if you\u2019re storing it outside for a month, that thin film might let enough moisture in to cause mold on the wood. Crank that up to 100-gauge, and the WVTR drops, so your pallet stays dry longer. I always tell customers to match thickness to their timeline and storage\/transport conditions\u2014no need to pay for 100-gauge if you\u2019re just moving pallets across a dry factory floor.<\/p>\n

But here\u2019s a catch: moisture resistance isn\u2019t the only thing. Blown stretch film also needs to stretch, right? That\u2019s the whole point\u2014you wrap it tight, it clings to itself, holds the pallet together. If we make the film too thick, or tweak the resin too much for a better moisture barrier, it might lose its stretchability. No one wants a film that won\u2019t stretch 200% like it\u2019s supposed to, because then you can\u2019t get a tight wrap. We balance that every day in our lab\u2014test different resin blends and thicknesses so you don\u2019t have to choose between holding your pallet tight and keeping moisture out.<\/p>\n

Now, let\u2019s talk about when moisture resistance actually matters, because not every shipment needs top-tier WVTR. If you\u2019re shipping dry goods like metal parts that rust if damp, or frozen food that can develop freezer burn (wait, freezer burn is actually from moisture loss, right? Oh, right\u2014if the film isn\u2019t a good moisture barrier, the ice in the food sublimates out, so you get freezer burn), or raw materials like powdered chemicals that clump up when they get even a little damp\u2014then moisture resistance is non-negotiable. I had a customer a few months back who was shipping powdered detergent to a overseas market. They were using cheap thin blown film, and by the time the shipment got to the port, half the pallets had clumped powder because the film let in humid ocean air. They switched to our 90-gauge co-ex blown film, and haven\u2019t had a problem since. That\u2019s the kind of thing I\u2019m talking about\u2014getting the right moisture resistance saves you from losses, not to mention the hassle of returns.<\/p>\n

Wait, but what about outdoor use? If you\u2019re wrapping pallets outside, in rain or high humidity, the film\u2019s moisture resistance has to hold up even in extreme temps. Cold weather, for example\u2014PE gets stiffer when it\u2019s cold, right? Does that affect moisture resistance? Surprisingly, no\u2014because the molecular structure of PE stays pretty consistent in cold temps, unlike some other plastics. High humidity when you\u2019re wrapping, though\u2014if you wrap a pallet in 90% humidity, the film might cling a little differently, but the moisture barrier itself doesn\u2019t change much. I\u2019ve tested our film at 30\u00b0F and 90\u00b0F, and WVTR only shifts by like 10-15%, which is negligible for most applications. The big thing with outdoor wraps is also UV resistance, but that\u2019s a separate conversation\u2014though we can blend UV inhibitors into our blown film too, so you get both UV protection and good moisture resistance.<\/p>\n

Is there a myth I hear all the time? That \u201call blown stretch film is the same for moisture resistance.\u201d No way. I\u2019ve seen cheap blown film from overseas suppliers that has a WVTR of 10 g\/m\u00b2\/day or higher\u2014because they use lower-grade resin, skip the proper cooling during extrusion, so the molecular gaps are bigger, letting moisture seep through way easier. That\u2019s why it\u2019s not just about the label, it\u2019s about working with a supplier that tests their film\u2019s WVTR regularly. We test every batch we make in our in-house lab\u2014no exceptions\u2014so we can give you exact numbers, not guesses.<\/p>\n

Another thing: cling. Wait, cling is different from moisture resistance, but they can play off each other. If your film has good cling, it\u2019s tighter on the pallet, which actually reduces the amount of surface area where moisture could seep in around the edges. But that\u2019s a secondary benefit\u2014you still need the WVTR to be low enough. We add cling agents to our blown film, so you get the tight wrap and the moisture barrier at the same time.<\/p>\n

So how do you pick the right moisture resistance for your needs? Let\u2019s break it down quick:<\/p>\n

    \n
  1. If you\u2019re shipping short distances (under 50 miles), dry warehouses, no sensitive goods: 60-80 gauge standard LLDPE blown film, WVTR 5-7 g\/m\u00b2\/day is enough.<\/li>\n
  2. If you\u2019re shipping longer distances, moderate humidity, semi-sensitive goods (metal parts, non-clumpy powders): 80-90 gauge blended blown film, WVTR 4-6 g\/m\u00b2\/day.<\/li>\n
  3. If you\u2019re shipping overseas, outdoor storage, high humidity, super sensitive goods (food, chemicals, electronics): 90-120 gauge co-ex blown film, WVTR 2-4 g\/m\u00b2\/day.<\/li>\n<\/ol>\n

    That\u2019s a rough guide, but every shipment is different. Maybe you have a pallet that\u2019s going to sit on a dock for 2 weeks before shipping, so you need a bit more barrier. Maybe your goods can handle a little damp, so you can go thinner. The worst thing is using too much, because you\u2019re paying for thicker film than you need\u2014we hate that too, because we want our customers to get the best value, not just more product.<\/p>\n

    Wait, let\u2019s address a common question: can moisture resistance change over time? Like, if the film is on a pallet for 6 months, does it start letting more moisture in? For standard blown PE, no\u2014PE is pretty stable. The WVTR stays consistent for like 1-2 years, as long as you store the film in a cool, dry place (which we always recommend\u2014don\u2019t leave rolls in the sun, that can break down the resin and hurt barrier properties). If the film is stored right, moisture resistance doesn\u2019t degrade much over time. That\u2019s important for long-term storage, like if you\u2019re wrapping pallets for a warehouse hold.<\/p>\n

    I know, this sounds like a lot, but it\u2019s all about matching your film to your use case. If you\u2019re not sure, just reach out. We don\u2019t do one-size-fits-all here\u2014we\u2019ll ask you what you\u2019re shipping, where it\u2019s going, how long it\u2019s wrapping, and then we\u2019ll recommend the exact blown stretch film with the right moisture resistance. No pushy sales talk, just straight answers. We\u2019ve been in this business long enough to know that the best partnerships are when we help you solve a problem, not just sell a product.<\/p>\n

    <\/p>\n

    At the end of the day, blown stretch film\u2019s moisture resistance is a make-or-break feature for a lot of shipments. Skip testing, skip matching the right resin and thickness, and you\u2019re looking at ruined goods, lost money, upset customers. We don\u2019t want that for you. So if you\u2019re tired of dealing with film that doesn\u2019t protect your goods from moisture, or you\u2019re just trying to figure out which film is right for your next shipment, hit us up to connect and chat through your needs. No hidden fees, no confusing specs, just a clear recommendation that works for your budget and your products.<\/p>\n

    Packaging Labels<\/a> References:<\/p>\n

      \n
    1. Harper, C. A., & Petrie, E. M. (2010). Plastic Materials and Processes. McGraw-Hill.<\/li>\n
    2. Sorrentino, A., Gorrasi, G., & Vittoria, V. (2007). Potential of biopolymers in packaging applications. Trends in Food Science & Technology, 18(4), 184-196.<\/li>\n
    3. American Society for Testing and Materials (ASTM). (2018). Standard Test Method for Water Vapor Transmission Rate of Flexible Barrier Materials (ASTM E96). ASTM International.<\/li>\n
    4. Welle, F. (2011). Translate-rules for the mechanical recycling of polyolefin packaging waste. Waste Management, 31(9), 1916-1927.<\/li>\n<\/ol>\n
      \n

      Huizhou Yufeng New Materials Co., Ltd.<\/a><\/p>\n

      Address: 9th Floor, Building A9, Zhongchuang Yingke New Generation Industrial Park, Tonghu Town, Huicheng District, Huizhou City
      E-mail: liangjun@kaiyudianzi.com
      WebSite:       https:\/\/www.yufengstickers.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

      What\u2019s the moisture resistance of blown stretch film, and why does it matter for your shipments? … What is the moisture resistance of blown stretch film?<\/span>Read more<\/a><\/p>\n","protected":false},"author":350,"featured_media":3608,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[3571],"class_list":["post-3608","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry","tag-blown-stretch-film-4d47-f8dba8"],"_links":{"self":[{"href":"http:\/\/www.almizhariya.com\/blog\/wp-json\/wp\/v2\/posts\/3608","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.almizhariya.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.almizhariya.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.almizhariya.com\/blog\/wp-json\/wp\/v2\/users\/350"}],"replies":[{"embeddable":true,"href":"http:\/\/www.almizhariya.com\/blog\/wp-json\/wp\/v2\/comments?post=3608"}],"version-history":[{"count":0,"href":"http:\/\/www.almizhariya.com\/blog\/wp-json\/wp\/v2\/posts\/3608\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.almizhariya.com\/blog\/wp-json\/wp\/v2\/posts\/3608"}],"wp:attachment":[{"href":"http:\/\/www.almizhariya.com\/blog\/wp-json\/wp\/v2\/media?parent=3608"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.almizhariya.com\/blog\/wp-json\/wp\/v2\/categories?post=3608"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.almizhariya.com\/blog\/wp-json\/wp\/v2\/tags?post=3608"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}