To say that polythene is widely used and has many functions would be an immense understatement. Plastic is the worlds most durable substance and polythene (or polyethylene) is just one of it’s forms that we use and rely on day in day out in our homes and businesses. Polythene is recyclable and this helps it be used time and time again, meaning we don’t need to throw it away and replace it as often as we do with other substances that we use daily. That being said polythene does eventually have a shelf live and the time does indeed come it has served its purpose. Methods of extending the lifespan of polythene products are used to save individuals and businesses money. Polythene is versatile and hardy but not invincible, it is eventually prone to the slow decay of wear and tear like any other substance. Fortunately then anything that can slow this process down is a welcome sight, to our wallets and the environment.

Benefits of VCI Polythene

Polythene is used as packaging for innumerable products, it is valued for it’s protective qualities. Keeping its contents free from corrosion. Thick ‘high density’ polythene is famous for it’s qualities as a moisture barrier, keeping its contents dry and in an airtight space where harmful and corrosive chemicals can’t seep in and damage the contents. Polythene is effective but it isn’t perfect, some contents that we wrap in polythene are easily corrodible just by their very nature, metal for example, in this case science needs to step in and lend a hand.

Volatile corrosion inhibitors in Bags

Volatile corrosion inhibitors (shortened to VCI on most products) are used to keep the contents wrapped in polythene free from natural corrosion. Some metals can corrode at any point in storage, transportation or even earlier in the first stages of a manufacturing process. This is of course dependent on the environment the parts are kept in and so many other factors, but the fact is any metal parts of a manufactured product are at risk of corrosion at any time. Not every product will immediately get wrapped in VCI bags, and at some stage will be vulnerable wherever they spend their time before it. A company making sure it is using VCI packaging sets itself apart from those who do not, and helps them ship better quality parts.

How do VCI’s work?

But what exactly are volatile corrosion inhibitors and how do they work? VCI’s are chemicals that are added to certain products before they are wrapped for storage which then slowly release chemical compounds into the sealed airspace that actively prevents surface corrosion. For example, releasing certain molecules into the space can help protect certain metals from going rusty. These effects coupled with polythene’s properties as a moisture barrier make VCI polythene easily the most effective substance in the world for storing and transporting certain materials. Here is some of the science behind how it works.

Providing a Protective Barrier

VCI technology serves as a protective barrier for external objects like grime and bacteria or anything else that could pollute the atmosphere it’s working within. Preventing contact between the material and the outside world, such as any corrosive gases (like oxygen itself), which could cause any form of slight chemical distortion that may be damaging over time. The chemical barrier that acts as the corrosion inhibitor is completely safe to humans. The compound is non-flammable, non-toxic, odorless, invisible, non-reactive and non-allergenic. In short unless you know it’s there already most people will not have a clue when they unwrap the item that’s using a VCI. Tests have shown that inhalation of VCI chemicals is harmless as would be ingesting it, but common sense should dictate that this is not recommended all the same. After all nobody has ever recommended eating polythene.

Helpful to Protect against Corrosion

The chemical reaction that regulates the corrosion between the metal and oxygen (or whatever else might be floating about) happens instantly and remains continuous throughout the whole time these items are together in a sealed space until they are separated. Corrosion on metal is the result of something called oxidation. When we think of oxygen we think of a gas that is essential for us to breath and stay alive, we associate it with a clear, clean and essential ingredient for life, pushed into the atmosphere by trees and plants maintaining the eco system of our planet. This is absolutely right but there is much more to oxygen then most of us know. To nearly everything else other than us, oxygen is a corrosive noxious and even flammable gas. It’s perfectly safe to us but pure oxygen, unless mixed with nitrogen and carbon dioxide (the 3 main gasses that make up our atmosphere) is a rather volatile substance. Oxidation is a rather destructive molecular reaction between the gas itself and the surface of a metal.

Protects Against Rust

This process doesn’t weaken the metal itself but it does cause it’s surface to slightly disintegrate, which can be catastrophic to products that need to be shipped and remain in pristine condition. VCI also protects against rust, which can utterly destroy an essential metal part of any product. This is particularly damaging if it happens to a small essential metal component, which cannot be replaced. Making an entire potentially expensive product useless on arrival. VCI packaging ensures this does not need to be the case and maintains the purity of a product meaning any items you package within VCI polythene reaches it’s intended destination exactly as described. While the chemical reaction caused by VCI technology is immediate, it can reach 12 to 24 hours to reach its maximum effectiveness.

Corrosion itself is a chemical reaction between the environment and the substance/material in question that results in deterioration of the properties that make up the material. Corrosion takes many forms (such as rust) but can also be subtler and not detectable by the naked eye. Luckily most corrosion occurs on a materials surface layer rather than internally, but it depends of course on the properties of the material in question. Naturally it’s best to do everything possible to protect against corrosion if an item/product is going into storage, being transported or delicate in some other way.

Adjusts to the Temperature

VCI technology works by creating an invisible and subtle layer of molecules around the surface of a substance that is constantly reinforced by the chemical reaction described above. The compound that makes up this corrosion inhibiting spreads all over the surface, slipping into all the nooks and crannies, maintaining a persistent shield over the entire structure. The VCI packaging also adjusts to whatever the temperature and humidity may be. This is especially effective with polythene which itself is ideal when used as packaging in areas that are particularly humid.

VCI Technology

One of the most staggering things about VCI technology when used within polythene is it can protect it’s contents from corrosion for up to three years. This is of course providing the packaging has not been punctured and the airtight environment has not been compromised in any way. Any rupture of this environment could cause more air to get in reducing the effects of VCI until it no longer works. VCI packaging from high-density polythene are largely resistant to penetration by any foreign vapors as well as being an effective moisture barrier. There is more risk of this in areas of high humidity but with climates like that of the UK this is much less of a risk. Should a small amount of moisture build up within the packaging, the VCI reaction will continue to be as effective as before.


The shelf life of VCI product (for example a polythene bag) is especially important for re-use of a product using VCI technology. If the VCI packaging is still in good condition then it can indeed be reused. Of course by this point chances are the packaging will have been exposed to the air, limiting its effectiveness over time. However if an item is removed from VCI packaging quickly and carefully there is no reason the item cannot be re-used straight away. If the VCI product is in poor condition, damaged, torn or contains multiple punctures then it is unlikely it will be as effective as it was before. These items however can be recycled and repurposed.

If you have used VCI polythene bags that are slightly worn you can use these as wrapping to take advantage of their protective qualities. However do not expect this to be as effective as it was before, it’s also not recommended to use it as a bag again once the damage is done. Small tears and punctures can be patched over or the polythene can be folded over and stitched, but this is something you will need to take the initiative with. If you feel it’s not worth the risk of using again then don’t. Re-use may save money in the short term but if something goes wrong with shipping, or the items don’t arrive/remain stored in the condition they are supposed too, then this can be rather damaging to a companies image and drive complaints. Cutting your losses, recycling the old and investing in the new is often more ideal.

OK to use with lightly oiled parts

Some products may require a light oil coating on the item being packaged by VCI technology. This is okay providing it is indeed light, a heavier oil coating will increase the risks of contamination and corrosion. VCI is still ideal and useful but it’s important to know that this may not be the same as with products that do not require a light oil coating. If VCI is required then it’s definitely better to use it then to not use it. After all the benefits are plenty. In some cases a product may already be corroded, applying VCI packaging will suspend this, slowing the corrosion process down significantly. To be clear VCI technology will not stop the corrosion entirely but it will prevent the effects from being as drastic.

Helps Prevent Corrosion even after use

VCI technology continues to work on a material long after the material has been removed from it’s packaging. Of course this wildly depends on what the material is and the environment it’s be put into, but generally the molecules that were used in transit/storage are still prevalent and will continue to work. This of course will not be exactly the same as if the material still being packaged, but when compared to a material that was not packaged using VCI technology the difference in corrosion rate will be obvious.

VCI Products

When storing VCI products before use make sure they are kept clean, dust free, out of direct sunlight and somewhere dry. Keep them as they are at room temperature. Exposing them to anything that could contaminate them risks compromising the effectiveness of the packaging when the day comes to use it. This of course can have a negative effect on the product being packaged and could result in a business that invests in VCI for it’s packaging needs not repeating their custom. The more success stories the better when repeat business is concerned. Good reviews from client experience will make investing in VCI worthwhile. The company providing the VCI packaging benefits, the company shipping their products benefits and the client ordering the product benefits. This is why it’s so important to get it right every time, but especially the first.

VCI Film

When VCI is used in conjunction with polythene it is known as VCI film. Polythene and VCI technology is a match made in heaven due to the already durable nature of polythene, it’s effectiveness as a moisture and vapor barrier and it’s versatility. The environment created by polythene already is ideal for VCI and VCI film is said to have a shelf life of nearly 5 years. Where VCIs were not actually made with polythene in mind they have become two things, which are used together more than most other industrial pairings. Polythene is one of the most used and versatile substances on the planet and when used in conjunction with effective VCI technology it’s possibilities are endless.