For any product, it is the desired property set that determines the best material for the application. The most important properties, such as physical, mechanical, optical, thermal, and electrical, provide fitness-for-use in the final product, In addition to final product (solid-state) properties, processing properties are also very important in material selection. Ease of processing in blown film can be described by characteristics such as good thermal stability, high melt strength (outside of the die), reasonable head pressures, and no melt fracture (film surface imperfections). Finally, the minimal cost is a key property.

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There are numerous applications for blown film, but a very high percentage of the film is used in commodity applications, such as packaging and bags. These products require a combination of performance, processing, and cost that make polyethylene (PE) the ideal polymer for most applications. It is lightweight, water-resistant, has a good balance of strength and flexibility, and can provide some clarity. PE is easy to extrude and heat-seal and, perhaps most importantly, is low cost. In addition to these general properties of PE, it is a polymer that is very well understood scientifically, allowing for polymerization techniques that can be designed and controlled to yield specific property values over a very wide range. That is, PE grades can be produced that are much stronger than average, much clearer, or much more flexible, and so on. Within the broad family of polyethylene, there are several types that find application in blown film. There are, however, other polymers used as well. While a few of these others are used in monolayer specialty films, they are mostly used as part of coextruded multilayer films, where multiple extruders feed a single die that combines the various feed streams into a single, multilayer film. The following sections detail the many polymer types used in blown film extrusion.

1. Polyethylene (PE)

Polyethylene (PE) is the simplest polymer from a chemical standpoint. It is polymerized from ethylene monomer and consists of a carbon chain backbone with two hydrogen atoms bonded to each carbon atom. Individual molecules, or chains, may be as long as hundreds to tens of thousands of carbon atoms. PE chains may be very linear or may be branched, depending on how the polymer was synthesized. There are many synthesis techniques for polyethylene. 

Blown film processing methods for PE vary somewhat depending on the grade. Differences will be discussed in the following sections. However, one important similarity is that all PE grades have a high value of specific heat. Specific heat is a measure of the energy required to raise a unit mass of material one degree in temperature. If a polymer has a high value of specific heat, this means that heat removal from the melt is relatively slow. PE has a specific heat of approximately 2 kJ/kg·K compared to approximately 1 kJ/kg·K for most other polymers. This is the reason why cooling towers for blown film polyethylene are very tall. It takes time to remove enough heat from the two layers passing through the nip rollers to prevent them from sticking together (sometimes called blocking).

2. Low-Density Polyethylene (LDPE)

Polyethylene is often categorized by its density, a measure of the mass per unit volume (e.g., g/cm3 or lb/in3). When any type of polymer cools from the melt state, some of the chains may organize into highly ordered, more dense crystalline regions.

This will occur with sections of molecules possessing long, repeating patterns. In sections containing irregular patterns, such as branch points or chain ends, crystallization does not occur and these regions are called amorphous (disordered). Some polymers, such as commercial polystyrene, are completely amorphous due to hindrance of the entire molecular structure to crystallization. Low-density polyethylene (LDPE) is synthesized in such a way that a highly branched polymer is formed. It consists of short chain branches (less than six carbon atoms long) and long chain branches (almost as long as the length of the backbone). Branch points along the chain serve as disruptions to the order of the system and prevent local crystallization. The lower level of crystallinity results in lower density. LDPE is generally in the density range of 0.91 to 0.93 g/cm3.

LDPE tends to be relatively easy to process. Compared to other PE grades, it melts at a relatively low temperature (220 to 240 °F, 105 to 115 °C) and does not require as much extruder motor power. LDPE blown film grades are moderately high in viscosity, but the wide range of branching yields a fairly wide processing window and high melt strength in the bubble. This leads to a stable bubble that can be run with a low frost-line height ( pocket bubble, or bowl or pear shape, Fig. 1.3). LDPE heat-seals very easily.

The properties of LDPE blown film can be characterized as tough and flexible. The toughness is derived from a good combination of strength and elongation, particularly when processed with high machine and transverse direction orientation. Flexibility results from low crystal content. LDPE bags provide a soft feel compared to the crinkly feel of HDPE bags. However, LDPE is not as stiff or strong as HDPE.

3. High-Density Polyethylene (HDPE)

High-density polyethylene (HDPE) is synthesized by a method very different from that used for LDPE. As a result, very linear chains are produced. In fact, HDPE is generally polymerized with a small amount of comonomer that leads to a few short chain branches placed intentionally along the main chain to make the polymer easier to process (Fig. 1.4). A high degree of linearity results in a high percentage of crystallinity (i.e., high density). HDPE is generally in the density range of 0.93 to 0.96 g/cm3.

Processing HDPE is somewhat different than processing LDPE. Because of its higher degree of crystallinity and more consistent molecular structure, HDPE melts at a higher temperature (265 to 275 °F, 130 to 135 °C) and has a narrower processing window. It also requires higher screw torque, hence more motor power. To promote good solids feeding via high barrel/pellet friction, grooved feed throats are often used.

One of the most obvious differences between processing HDPE and LDPE is that HDPE is usually run with a high frost-line height ( long stalk or wine glass shape, see Fig. 1.3).

The frost-line height is generally on the order of eight to ten times the die diameter. HDPE tends to have lower melt strength than LDPE, so bubble stability may be more of a problem. By delaying transverse stretching of the bubble until the melt is cooler (i.e., having a high frost line), the bubble remains more stable.

HDPE has high strength and stiffness among polyethylene grades. As a result, there is continual progress in the area of reducing the thickness of HDPE film products ( downgauging). Additionally, HDPE has reasonably good barrier properties (resistance to gas permeation) owing to its high degree crystallinity.

4. Linear Low-Density Polyethylene (LLDPE)

Linear low-density polyethylene (LLDPE) is a variation of HDPE. It is synthesized similarly, but LLDPE has a much higher content of comonomer, such as hexene or octene. Incorporation of comonomer in the chain yields short chain branches of a specified length (Fig. 1.5). By controlling the amount of branch points through comonomer content, degree of crystallinity – hence density – can be controlled. Variants of LLDPE are known as very low-density polyethylene (VLDPE) and ultra low- density polyethylene (ULDPE). LLDPE density is generally in the range of 0.88 to 0.93 g/cm3.

With regard to processing, LLDPE is something of a mixed bag (melt temperature = 240 to 260 °F, 115 to 125 °C). Inside the extruder it performs similarly to HDPE, requiring higher torque and often employing a grooved feed throat. However, outside of the die it is generally processed with a pocket bubble like LDPE, even though the melt strength tends to be lower than that of LDPE. This is handled by using a dual lip air ring that aerodynamically stabilizes the bubble while providing a high volume of cooling air.

LLDPE solid-state properties also reflect a combination of those of HDPE and LDPE. Its strength is higher than that of LDPE, approaching that of HDPE. However, it has the softer feel and lower stiffness of LDPE.

5. Metallocene Polyethylene (mPE)

Metallocene polyethylene (mPE) is a broad class of polymers made from ethylene that are synthesized using metallocene catalysts during the polymerization process. Also known as constrained geometry catalyst technology and single-site catalyst technology, this relatively new technique provides very precise control over molecular structure, thus allowing the chemist to accurately design a wide class of polyethylene types based on chain length, chain length distribution, and branching structure. While mPE materials are much like other PE grades, they can be produced with a very wide range of properties. One of the key property benefits is the ability to synthesize very soft, flexible grades. These provide some interesting opportunities for final film products, but a feed material that deforms easily and melts quickly requires some process modifications.

6. Polypropylene (PP)

Traditionally, polypropylene (PP) has been synthesized from propylene monomer by a method similar to that used for HDPE. Since this technique yields a very regular pattern along the chain, PP is able to crystallize. Because propylene monomer is slightly larger than ethylene monomer (the monomer is called a “repeat unit” once it is incorporated as links in the chain, Fig. 1.6), PP crystal structure is somewhat different than PE crystal structure and has a higher melting point. Also, PP is generally stronger and stiffer than PE. So, it can be used in applications requiring a higher use temperature and more strength. Examples include medical bags that can be autoclaved, hot liquid drum liners, and release films for construction materials.

Recently many new polypropylene grades have been synthesized using metallocene technology, similar to that used for ethylene. This has widened the range of property offerings in areas such as stiffness, impact strength, melting point, and clarity. Additional property sets are available from PE/PP copolymers, materials synthesized using both ethylene and propylene monomers. These find many applications in food packaging because of its good clarity resulting from low crystallinity.

Other than a potentially higher temperature profile (melt temperature = 330 °F, 165 °C), processing PP is similar in ease to processing PE. Both materials are thermally stable compared with other polymers, do not require drying, and decrease in viscosity readily at higher screw speeds (shear thinning). One notable exception, however, is that PP generally has a lower melt strength than PE, particularly compared with LDPE. In blown film processing, this can lead to difficulties with bubble stability. PP can be used in both monolayer specialty fi lms and within a multilayer coextruded structure.

7. Polystyrene (PS)

Polystyrene (PS) is generally synthesized by a method yielding an irregular pattern along the polymer chains (Fig. 1.7), hence preventing crystallization. Since the resulting polymer is completely amorphous (glass transition temperature = 210 °F, 100 °C), it possesses excellent clarity. This, along with its high strength and low cost, are the most important commercial properties of PS.

However, because the chains are very stiff, it possesses a detrimental level of brittleness. PS films can crack easily when folded and slight imperfections, such as gels, readily cause tears that propagate rapidly. For this reason, PS is generally blended with some amount of rubber-containing modifier, such as styrene-butadiene copolymer. Although at higher levels the rubber additive may reduce clarity, it makes PS films mechanically tougher and easier to process. Still, blown film processing of PS is significantly moredifficult than PE.

Even though PS cools more quickly than PE, it is usually processed at a much lower rate because the film is sensitive to damage. Care must be taken to ensure good melt filtering so that contaminants do not cause bubble breaks. Also, winding and slitting equipment must be designed and operated such that film scratching and cracking is prevented.

Applications for single- and multilayer PS fi lms include food and candy packaging, clear gift wrap, and envelope windows. Because of the ability of PS films to allow gas (such as air) to permeate through them, particularly with higher rubber concentrations, they have been used in breathable produce packaging that provides continued ripening on store shelves.

8. Ethylene Vinyl Acetate (EVA)

Ethylene vinyl acetate (EVA) is a copolymer of polyethylene. It is similar in chemistry to PE, but it has some percentage of vinyl acetate (VA) included along the chains (Fig. 1.8). The amount of VA that is included, generally between about 5 and 20%, depends on the desired properties of the polymer. VA adds polarity, or adhesion, to the polymer and, so, improves the compatibility of the polymer with fillers and gives the polymer adhesive properties. Most blown film applications using EVA do so as layers in coextruded products, such as food and electronics packaging.

Figure 1.8 Schematic representation of an ethylene vinyl acetate molecule showing acetate side groups randomly located along the chain

9. Ethylene Vinyl Alcohol (EVOH)

Ethylene vinyl alcohol (EVOH) is similar to EVA in that it is a copolymer of polyethylene with some percentage of the vinyl comonomer along the chain. In fact, EVOH is synthesized by converting VA units along a chain into vinyl alcohol (VOH) units. Grades of EVOH can be purchased with either fully or partially converted VA units to provide a wide property set. Like EVA, EVOH is primarily used in layers of coextruded film structures.

EVOH has some important commercial properties. Perhaps the most important property is its resistance to oxygen permeation. For this reason, it is used as a barrier layer in multilayer food-grade films. Another important property of EVOH is that it is watersoluble. Therefore, it is used in applications such as the delivery of laundry detergent via dissolving packaging

10. Polyvinyl Chloride (PVC)

Worldwide, polyvinyl chloride (PVC) is one of the most extruded polymers by volume. While environmental and health concerns has created lost market share in certain applications, PVC has made large gains in other areas, such as the replacement of wood and aluminum profiles in building construction products. Blown film extrusion is also used in the manufacture of products from PVC. Though PVC has limited thermal stability, it has good melt strength, which lends itself nicely to blown film extrusion.

PVC is an amorphous polymer (glass transition temperature = 220 °F, 105 °C). As a result, it has good clarity. Another important characteristic is that it can be extruded either as a rigid material or as a flexible material by adding a plasticizer to the polymer. Rigid films can be metallized and punched into sequins for dressmaking applications. Flexible fi lms are used to overwrap clothing and other textile products. Two other important characteristics of PVC taken advantage of in film applications are barrier properties and heat-shrinkability. Because of these attributes, PVC film finds usage in food packaging, such as candies, as well as nonfood packaging, such as shrink wrapping of auto parts.

11. Polyamide (PA)

Blown film applications for polyamide (PA), also known as nylon, are primarily barrier layers in multilayer structures. However, PA has quite different processing characteristics than other layers, such as polyethylene, typically found in these coextruded films. For example, PA has a much higher processing temperature (generally > 500 °F, melt temperature = 360 to 480 °F, 180 to 250 °C) so the extrusion system, particularly the die, must be designed to provide proper temperature control to individual flow layers.

Also, PA is a hygroscopic material, meaning it absorbs moisture from the air, so it must be dried sufficiently prior to processing.

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There are also some specialty monolayer films blown from PA. One example is a high temperature film used as bagging material for composites processing.

12. Polyurethane (PU)

Polyurethane (PU) is a highly versatile material with a wide range of properties, depending on the chemistry of the specific grade. Blown film grades are thermoplastic (TPU) and either aromatic or aliphatic. Aliphatics are more expensive, but generally have better resistance to ultraviolet radiation and are clearer. PUs are also either polyetherbased or polyester-based, where the former has better low temperature flexibility and the latter tends to be tougher and more chemical resistant. Blown film grades of PU are usually easy to process because they are synthesized to have good melt strength. They are generally processed at temperatures between 350 and 400 °F (180 and 205 °C). However, they are highly moisture absorbent and, if not dried adequately, exhibit gels, streaks, and low melt strength.

Because of their high elasticity and toughness, PU blown films are generally used in specialty applications. One example is an adhesive laminating layer between fabrics. Another example is inflatable bladders used in rafts and kayaks.

VCI FAQs

VCI stands for vapor corrosion inhibitor technology and in a nutshell, it’s the “secret sauce” we infuse into our products — primarily packaging materials like paper or poly film — to fight off the unwanted advances of rust. VCI is a class of chemical compounds that emit rust-inhibiting vapors into an enclosed air space. When metal is present, the VCI molecules form a nano-sized layer of protection on the surface of ferrous and non-ferrous metal that displaces moisture and prevents corrosion.  At ARMOR, we make the analogy that VCI vapors knit together to form an invisible blanket that covers the surface of metal to shield it from moisture and the damaging effects of rust and corrosion.

ARMOR engineered highly-specialized vapor corrosion inhibitors to create its unique VCI formulation called ARMOR VCI Nanotechnology.  This “secret recipe” of VCI forms a rust-resistant protective shield on the surface of metal that is only a few molecules thick called a “nanocoating.”

Nanotechnology is described as the imaging, measuring, modeling and manipulation of matter in extremely small sizes of between 1 and 100 nanometers.  To illustrate just how small a nanometer is, consider these examples:

• One strand of human hair is between 80,000 and 100,000 nanometers wide.
• A sheet of loose-leaf paper is approximately 100,000 nanometers thick.
• The head of a pin is 1 million nanometers across.
• An ant is 5 million nanometers long.

ARMOR VCI Nanotechnology protects metal in ways that traditional oil and grease rust prevention methods can’t – it delivers a clean, dry ultra-thin and ultra-strong layer of protection on the surface of metal that is only 4-to-6 nanometers thick. The VCI molecules form a hydrophobic (aka, water-repelling) barrier that keeps dirt, water, moisture and other corrosion-causing contaminates away from metal.  ARMOR’s VCI formulation forms a layer of protection that is undetectable and that does not alter metal properties — it does not change the look, weight or feel of metal parts; it does not compromise metal surface coatings or treatments; and it leaves metal parts ready for immediate use without cleaning or degreasing.

When you wrap or enclose a metal part in an ARMOR VCI product, VCI vapors are released and they attach themselves to the surface of metal to form a nano-sized layer of protection that repels water, moisture and other contaminates that cause corrosion.  Traditional rust preventatives such as oil and grease offer a physical barrier to protect the surface of metal parts, but they are messy, time consuming to apply and remove, and are harmful to humans and the environment.  Vapor corrosion inhibitors (VCI), such as ARMOR VCI Nanotechnology, work on a molecular level and they are clean, dry, easy-to-apply, and VCI protection dissipates once metal part is removed from VCI packaging, which eliminates the need for removal.

ARMOR combines it proprietary VCI Nanotechnology with materials such as Kraft paper, poly film, chipboard or foam pad to create clean and dry packaging materials with the added benefit of rust prevention.  We infuse VCI into the packaging materials and manufacture them into rolls, sheets, VCI bags or tubing.  When metal/metal parts are wrapped or covered in VCI sheets or enclosed in VCI bags or tubing and placed in an enclosed container for storage or shipping, the VCI vapors release and form a protective layer on the surface of metal that repels rust.

When used properly, ARMOR VCI can protect metal parts for years. The VCI length of protection varies based on factors such as temperature and humidity, airflow, production and process methods, the surface conditions of metal parts and whether VCI products are stored properly before their use.  ARMOR offers a range of VCI products to protect a variety of metals and specific packaging requirements and ARMOR VCI products can also be combined or used together to extend the length of protection or to enhance the level of protection for more extreme conditions.

ARMOR VCI packaging materials are clean, safe and easy.  ARMOR’s VCI formulations are considered safe from causing serious harm. When used as directed, ARMOR VCI products are safe to handle and once the VCI packaging is removed, the VCI can dissipate from the metal surface without risk of contact or inhalation.  ARMOR strongly recommends that users follow the specific usage guidelines for handling and applying each VCI product to ensure users are safe.

Corrosion is the natural mechanism by which metal returns to its original state of ore.  If metal is exposed to moisture/water and oxygen, it breaks down and corrodes.  Corrosion of metal is an electro-chemical process.  The flow of electrons from high-energy areas of metal to low energy areas takes place through a solution on the surface of the metal, capable of supporting corrosion.  Corrosion will not take place without a conducting solution called an electrolyte – this conducting solution is caused by water, rain, moisture, and humidity.  As little as 65% relative humidity will form an electrolyte, which can cause corrosion.

Nitrites are used in VCI in the form of sodium nitrite. Sodium nitrite has been used as a food preservative for over 100 years. It is found in the bacon you eat for breakfast and the salami you eat for lunch. It has been approved as a food additive for over two-thirds of a century. In fact, over 85% of the sodium nitrite present in our body is produced by our own body. In order to consume the MSDS reported hazardous dosage of sodium nitrite, for a normal VCI at 1.0 g/sq. ft. a person would have to EAT all of the sodium nitrite present in 31 sq. ft. of VCI treated paper. Not only does a person not ingest VCI paper, but rarely comes into contact with it, given the fact that workers should wear gloves to avoid the acidity that our fingerprints give off on the metal surfaces.

Similar to most ordinary household chemicals, sodium nitrite is not without risk. It simply must be handled in the same judicious fashion as such ordinary chemicals as household bleach, windshield washer fluid, floor wax, and several others. None of these components would be considered as “hazardous” within normal usage; however, sodium nitrite is often singled out as if it is. While sodium nitrite in VCI Paper should not be construed in the same light as a food preservative, it is not the lethal enemy that some make it out to be. It is used in the VCI industry because it is an excellent inhibitor of rust, especially for steel products. Armor Protective Packaging® manufactures several different VCI products, with and without sodium nitrite. Please contact an ARMOR representative for information and help in specifying the correct product(s) for your application.

VCI paper — such as ARMOR WRAP® VCI paper — is a neutral pH Kraft paper that is infused with VCI and is manufactured in sheets or rolls.  When compared to VCI poly film, VCI paper has a faster diffusion rate – paper releases VCI faster, which allows VCI to form its protective shield on the surface of metal parts more quickly.  That is not to say that VCI poly – such as ARMOR POLY® VCI film – is not an excellent rust preventative or that it does not have its place.  VCI poly, which is a polyurethane film with added VCI that has been manufactured in rolls, sheets, bags, tubing and shrink film, offers strong, moisture barrier properties and provides a physical barrier to protect metal from dust and contaminants.  While VCI paper diffuses VCI more quickly, VCI poly offers a greater level of barrier protection.  Both have their advantages depending on the environment that metal is being shipped or stored in.

Ferrous metals contain iron and while they are known to be durable and strong, they also have a high carbon content that makes them more susceptible to rust.  Examples of ferrous metals include steel, carbon steel and cast iron.  Non-ferrous metals do not contain iron and they are known to be malleable, lightweight and less likely to rust.  Examples of non-ferrous metals include aluminum, copper, brass, gold, silver and lead.

VCI and desiccants protect metal parts in very different ways using very different chemistry.  One way to explain their differences is using a give-and-take analogy.  ARMOR’s proprietary VCI Nanotechnology “gives” or emits a vapor that prevents corrosion by forming a protective layer on the surface of metal.  Desiccants are drying agents that “take” or adsorb moisture from the packaging environment, which is one of the main causes of corrosion.  Depending on the application and the particulars of the storage or shipping environment, one method may provide better results than the other or, VCI and desiccants are often used together to provide premium protection of metal parts in highly-demanding packaging environments.

In , ARMOR formally combined VCI and desiccant together to create its SMARTY PAK™.  The SMARTY PAK design not only emits ARMOR VCI Nanotechnology, it uses a specialty desiccant that adsorbs moisture faster than traditional desiccants and holds on to the moisture even at high temperatures.  SMARTY PAKs are available in three sizes, they deliver multi-metal protection, and they are non-dusting and lint-free making them ideal for use in applications where fibrous packaging materials are not allowed.

VCI paper — such as ARMOR WRAP® VCI paper — is a neutral pH Kraft paper that is infused with VCI chemistry and is manufactured in sheets or rolls with the option to add barrier coatings such as wax or poly for increased protection against moisture, grease/oils or a scrim coating for added durability and tear resistance. ARMOR WRAP is also available in different formulations including global, multi-metal protection and military-approved.  The key advantages of ARMOR WRAP VCI paper are:

1. Fast diffusion rate – paper releases VCI faster, which allows VCI to form its protective shield on the surface of metal parts more quickly.
2. ARMOR WRAP VCI paper is environmentally safe and fully recyclable and repulpable.
3. Flexible packaging material that easily forms around various sizes/shapes of metal parts.
4. ARMOR embeds VCI on BOTH sides of its ARMOR WRAP paper to simplify and foolproof its use.
5. Combines easily with other VCI products to protect metal parts in extreme conditions.
6. More than 50 years in existence with long-standing use by the United State Military.

ARMOR WRAP VCI paper is infused with VCI on BOTH sides of the paper (different from the one-sided format manufactured by most VCI companies) to eliminate confusion as to which side of the paper to place against metal part when wrapping and to enhance interleaving capabilities within a pallet of metal parts.  The result is less paper, less waste and less cost.

VCI Poly – such as ARMOR POLY® VCI film — is a polyurethane film with added VCI chemistry that has been manufactured in rolls, sheets, bags, tubing and shrink film for use in packaging and protecting metal parts from rust and corrosion.  The key advantages of ARMOR POLY VCI film are:

1. Provides a strong, moisture barrier in addition to its VCI corrosion inhibitor.
2. Ease of use – metal parts are placed into an ARMOR POLY VCI bag or a shipping/storage container lined with a VCI poly bag and closed – ARMOR POLY is also heat sealable.
3. Provides a physical barrier to protect metal/metal parts from dust and contaminants — often a customer is already using a poly bag for this purpose.  Using an ARMOR POLY® VCI bag provides the same protection with the added benefits of rust prevention.
4. Translucency of film allows for simple identification and inspection of contents without removal.
5. ARMOR POLY VCI films contain ARMOR’s Bright Idea Technology™ — under a black light they emit glowing visible proof that VCI is present.
6. Combines easily with other VCI products to protect metal parts in extreme conditions.

Corrugated cardboard is made from paper.  An early step in the method for making paper involves treating raw wood with chemicals to break it down into a fibrous pulp – it is an acidic process and it can leave an acidic residue on cardboard.  One characteristic of corrugated cardboard is it is absorbent and when it absorbs water/moisture it causes the acidic residue to activate.  If metal or metal parts in storage or transit are placed directly on or near damp corrugated cardboard, the moisture and acidity will induce corrosion on the surface of metal parts.  Placing ARMOR VCI products between metal and corrugated cardboard will prevent corrosion and keep metals clean and rust-free.

Diverse needs call for diverse solutions. That is why ARMOR offers over 12 types of ARMOR WRAP® papers to choose from for your specific VCI needs. Some VCI manufacturers incorrectly claim that a single formulation will protect everything from steel to copper, others are vague or cannot tell you how much VCI is actually in the product. The fact is no single VCI formulation for paper can provide true corrosion-free protection for all metals and applications.

Due to the abundance of metals available, as well as the numerous coolants, washes, rust preventative oils and other substances used within a manufacturing process, it is important to check VCI compatibility with these substances.  While it is rare, on occasion there may be factors that either react adversely with a particular VCI formula or react to diminish the performance of an ARMOR VCI product.

Metal parts are manufactured in different sizes, shapes and metal compositions.  In addition, they are exposed to a variety of environmental conditions and vary greatly in the length of protection they require.  VCI is not a one size fits all formulation or product and for that reason, ARMOR offers a wide range of VCI products to keep metal rust-free.  ARMOR WRAP® VCI paper, ARMOR POLY® VCI film, chip board, foam pad, emitters and liquids are designed to ensure that metal is protected from corrosion while in process, in storage or in shipping/transport.

It is not required but, the more airtight the packaging the more effective the VCI protection.  To optimize the rust-prevention benefits of VCI, airtight packaging is recommended.  If packaging is less than airtight, VCI can protect metal parts but its effectiveness will be reduced.  What is most important when using VCI packaging is keeping VCI vapors contained as much as possible — the more airtight the enclosure the more effective the VCI protection will be.  Conversely, if the packaging is not airtight and the VCI vapors are able to escape, the strength of the VCI (and its ability to protect metal parts from rust) will diminish.

ARMOR carries a variety of military-approved papers that are listed on the U.S. Department of Defense Qualified Products List (QPL).  These products are tested in accordance with, and labeled as, required in the Military specification MIL-PRF- (Wrapping Materials, Volatile Corrosion Inhibitor Treated, Opaque).

Human hands contain moisture and acidity that can be directly transferred onto metal parts and ultimately, cause corrosion.  To prevent the transfer of moisture, acidity and other contaminants, employees must wear gloves when handling metal parts.  The use of clean, cotton gloves (replaced once dirty), is essential to reducing overall rust and corrosion within the manufacturing process.

ARMOR offers full-service, in-house, accelerated corrosion testing at NO CHARGE to its customers. We use two, distinct methods to subject metal parts to accelerated conditions–a humidity chamber controlled at 98°F – 105°F and maintaining a relative humidity of 95 – 99% and traditional ovens with humidity features.

• Cost-effective protection
• Clean, dry packaging that is easy-to-apply
• Safe for people and the environment
• Flexible packaging materials easily form around differing sizes/shapes of metal parts
• Vapors penetrate hard-to-reach areas and replenish inside enclosure
• No messy grease, oils, or surface preparation required
• No need to remove VCI – metal parts can be used immediately
• Eliminates labor and cost of hazardous waste disposal
• Can provide years of corrosion protection

The ARMOR Stock & Ready® Program was designed to bring the ease and convenience of online shopping that we experience in our personal lives to the world of rust prevention/rust removal products.  ARMOR tripled its in-stock inventory, simplified order placement to include no order minimums, and implemented quick processing and turbo-fast shipping to establish the ARMOR Stock & Ready Program where all rust prevention/rust removal products on our stock list are in-stock and ready-to-ship.

• Your parts should be clean and free from corrosion before packaging
• Package clean parts as soon as possible after processing, manufacturing or cleaning
• Use gloves when handling parts to eliminate corrosion caused by fingerprints.

In our more than 40 years in business, ARMOR has never been contacted regarding an issue with VCI compatibility to non-metallic surfaces such as plastics, rubbers or wood.  However, since there are so many possible combinations of ingredients, processes and types of these substrates it is impossible to guarantee their suitability with ARMOR VCI.  Without question, rust prevention methods such as oils, greases and other liquid RPs (rust preventatives) have a much higher likelihood of reacting with plastics, rubbers and wood, but ARMOR strongly recommends a check of VCI compatibility with these substances for each application due to the complexity and number of plastics, rubber materials and woods in the marketplace.

With ARMOR VCI Nanotechnology, you will not see or feel any film, coating or finish on metal parts because our VCI delivers a clean, dry ultra-thin and ultra-strong layer of protection on the surface of metal that is only 4-to-6 nanometers thick.   ARMOR’s VCI formulation forms a layer of protection that is undetectable and that does not alter metal properties — it does not change the look, weight or feel of metal parts; it does not compromise metal surface coatings or treatments; and it leaves metal parts ready for immediate use without cleaning or degreasing.

• Metal parts should be clean and free from corrosion before
• Metal parts should be thoroughly dry to eliminate moisture in the packaging.
• Gloves should always be worn when handling metal parts to prevent the transfer of moisture, acidity and other contaminants from hands/fingerprints.
• Package metal parts as soon as possible after processing, manufacturing or cleaning.

Keep VCI products in original and/or tightly-sealed packaging that is stored inside and away from the elements.  For best results, do not leave ARMOR VCI product out in an open environment, either indoors or outdoors. Keep VCI product in airtight plastic packaging to preserve VCI and to protect product from contamination due to water, moisture, dirt, debris, etc… Store VCI products under shelter, securely inside a shipping carton, external bag, box or container and out of direct sunlight.

ARMOR can tell you exactly how much VCI is contained in our products to give your products the added insurance they need to remain corrosion free. For example, our papers contain a specified and measured amount of VCI additive, as measured in grams/square foot. This ability to monitor and control the amount is a testament to our quality and continued improvement. If a company cannot specify and consistently meet a given coating weight of VCI on a substrate, one runs the risk of having too little VCI to get the job done.

Armor Protective Packaging® corrosion management products provide approximately three years of protection for metal parts and surfaces when used properly in normal warehouse conditions. To ensure successful results, parts must be completely wrapped or enclosed – airtight packaging is the most effective for best results and longest protection time. Variable conditions such as temperature and humidity extremes, airflow, production and process methods, surface conditions of metal to be protected, customer employee training and other factors are impossible for ARMOR to control so it is impossible to guarantee a specific length of protection. Contact your ARMOR representative for details related to your specific application.

ARMOR uses a special mathematical formula for calculating the proper size VCI bag/bin liner/pallet cover to effectively protect metal parts.  Not only is it important that the VCI bag is large enough to completely cover metal parts, but allowances must be given to ensure the VCI bag also has ample overage to allow for proper tie off and sealing.  Insufficient overage can result in faulty seals and that can allow moisture to enter the bag while at the same time allowing VCI to escape.  Accurate bag sizing and proper seals are critical in export where temperature fluctuations and transport handling conditions can be extreme.

ARMOR VCI products are not recommended for re-use for three primary reasons:

• There is no way to determine the rate at which the VCI has volatilized out of the product and conversely, there is no way to determine how much VCI remains in the product for re-use.
• It is impossible to properly track or monitor the amount of time and/or environmental conditions that the VCI product has been exposed to in previous uses to verify if it is still effective.
• Re-use of a VCI product allows the potential for contaminants on or in the VCI packaging to be transferred.

For those instances when re-use is necessary, be sure VCI is like your favorite pair of jeans — clean, dry, free of tears, holes, or other contaminants.  It is also important to note that the length of time the packaging material has been exposed to the environment (especially high heat/humidity) will greatly impact the VCI’s effectiveness.  Do not re-use VCI packaging more than two times and note, ARMOR cannot guarantee the amount of VCI that remains in the packaging or substrate upon re-use.

It’s widely known that recycling helps to reduce the pollution caused by waste, it reduces the use of raw materials and it positively impacts the environment.  ARMOR WRAP VCI paper and ARMOR POLY VCI film are fully recyclable.  In addition, ARMOR utilizes recycled content in the manufacture of its VCI products whenever possible and we do it without sacrificing performance or raising price.

Oil, lubricants, and/or transmission fluids typically do not have any adverse effects when used in combination with VCI other than they inhibit the full potential of the VCI.  ARMOR VCI was developed to be used on parts that are clean and dry (free of RPs and oils). If parts are coated with these types of liquids, the VCI may not be able to penetrate through the coatings to get to the metal surfaces.   ARMOR VCI, will however, protect recessed areas or other areas where the oil/lubricant/transmission fluid is not, thereby guarding against corrosion in that regard. ARMOR recommends lab testing if there is concern regarding compatibility.

ARMOR VCI products are available for purchase both through industrial packaging distributors and the ARMOR Stock & Ready® Program.  Our Stock & Ready program was designed to bring the ease and convenience of online shopping that has become commonplace in our personal lives to the world of rust prevention/rust removal products.  ARMOR tripled its in-stock inventory, simplified order placement to include no order minimums, and implemented quick processing and turbo-fast shipping to establish the ARMOR Stock & Ready Program where all rust prevention/rust removal products on our stock list are in-stock and ready-to-ship.

For an authorized ARMOR distributor nearest you, please contact Armor Protective Packaging® by , (517) 546- or toll-free at (800) 365-, by fax, (248) 573- or by at .

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