The “Ins and Outs” of Polyethylene Pallet Covers
Joe! I need you to order 2,000 poly cover-bags for our shipment on the 15th!” the operations manager yells at 3:30 on a Friday afternoon. Being the purchasing agent for his company, it is inferred that Joe knows what a “poly cover-bag” is or what will be the best type, thickness, color or size to protect his product. If you know nothing about the polyethylene packaging industry, are looking for a specific answer like “how to measure” or are simply keeping up on recent market trends, this is the article for you.
Pallet Covers are used to protect your company’s product during transportation and storage. These days, pallet covers also serve as an effective means of advertisement as well as oversized trash bags. This article will teach you everything your manufacturer knows regarding this product. Therefore, it guarantees you will be a more effective buyer!
Pallet Covers and Bin Liners are often listed on subsequent pages in packaging supply catalogs. This is done because, in most cases, a liner is simply an inverted cover. First we’ll cover some basics of polyethylene custom films.
Polyethylene (PE) is a thermoplastic polymer, which is today’s most widely used plastic. Even the now nearly obsolete plastic grocery bag is a form of PE. I say nearly obsolete as the plastic grocery bag has begun to give way to the Non-Woven Polypropylene (PP) shopping bag as a green alternative. There are several different sub-categories of Polyethylene; 10 to be more specific. I do not intend to bore you with a chemistry lesson (nor am I qualified to teach one) so we will discuss the few that are used most often in the packaging industry. There are three sub-classifications you will most likely be interested in, depending on your specific packaging needs.
They are linear low density polyethylene (LLDPE), low density polyethylene (LDPE) and high density polyethylene (HDPE). LLDPE is known to have a higher resistance to punctures and higher overall strength than that of a LDPE. LLDPE is commonly used to make thin films due to its high strength. LLDPE can be found in stretch films, plastic wraps and nearly all polyethylene markets. Negatives for LLDPE are its smaller heat-sealing abilities and production challenges. Pallet cover users typically prefer LDPE for its “burly” chemical characteristics. It can also be found in many other applications such as playground slides and computer components. LDPE is not as dense as LLDPE and also has a lower tensile strength that requires a higher thickness be used in many applications. HDPE is more likely to be used in the manufacturing of extremely thin films such as t-shirt bags or grocery bags as it relates to our industry. Outside of the packaging industry, HDPE has many different applications and is seen as a very versatile product. We will move on with the LDPE (don’t forget Joe still has to get those bags ordered!).
What color? How many MIL thick? What is a MIL? Do I need a UVI additive? Should it be a shrink blend? What size? How many do I have to buy? How much will it cost? How “green” is it? Can I get my company info printed on it? How many print colors? How many print sides? Is it safe in cold weather? What is a gusseted cover? What is a center-fold and m-fold? How are they packaged? Don’t worry, we’ll get there.
Our friend Joe is employed by an industry leader in the manufacturing of dog food. His company is located in Miami, FL. Knowing the what, where, how long and size are a couple of determining factors in choosing the correct liner, or in this case cover.
Let’s say Joe has 40 lb bags of dog food that are produced in mass quantity, then loaded on skids and shipped to distributors all over the continental U.S. For this order, Joe will be going with a Low Density Polyethylene. If we were just looking for the lowest cost and not concerned with presentation or longevity a black, LDPE, “Repro-Blend” would be the route to go. Given today’s economy coupled with our nation’s concern with staying “green”, this has become a very popular choice.
The company’s owners are more concerned with marketing and presentation than just getting a low price. Now that we know we’re looking for a LDPE film, lets get more specific. Polyethylene resins can be “virgin” or a “virgin/repro blend” in this case. Many manufacturers only use virgin resin due to its quality and aesthetic value. Plus they are unable to quote on Repro products, as they do not have poly regrind machinery. When looking for the most economical choice, it is always good to find if your source has the capability to produce a product using recycled resin. Using a resin made partially of recycled polyethylene does allow your company to market it as a “green” product. Yes, it is a “plastic bag” which for some is the farthest thing from environmentally friendly. However, if your cover will eventually be used as a trash bag or disposed of shortly after being installed this may be the most economical route.
Polyethylene pallet covers can be manufactured in a wide array of colors. They also can be “Opaque” or “tinted”, which of course, refers to the color density. The pantone color system (PMS) is the most common color system used to choose these colors. As with anything, the more bells and whistles you add, the more your costs rise. If your product will spend a great deal of time sitting at its destination prior to being unpacked, an opaque color with artwork should be an option to consider. In Joe’s case, the owner wants both a good looking cover and increased marketing potential. White is always a great background for any print or logo to stand out on. So Joe should suggest white opaque film be used.
Shrink covers and bags are used to cover anything from a 30′ boat to a 2″ wide toy. A shrink cover is made of a film that does just that when heat is applied to it. In some applications the material is covered with a shrink film and moved through a heat tunnel. Other companies will use a heat gun to shrink the material around the product. If the decision is made to go with a shrink cover, additional tools will need to be purchased. Heat tunnels and heat guns do come with a high initial investment. Shrink products include; bags, covers, tubes and films. These items are installed to keep the pallet load secure and clean during transit and storage. Joe’s product is wrapped with stretch film prior to having the pallet cover installed. When this is the case, a shrink cover is not typically needed, as the load is secured by stretch film.
We learned earlier that Joe’s company is located in Florida and it transports throughout the country. This is relevant information as we begin to discuss a couple of additives often used in the manufacture of pallet covers. If the company was located in Minnesota, and the product sat in sub-freezing temperatures for long periods of time, EVA would be needed. EVA (Ethyl Vinyl Acetate) is an additive to prevent hardening and cracking due to the cold. Another common additive option requested in pallet cover production is UVI (Ultra Violet Inhibitor). This is needed if a covered load will be exposed to the sun, wind or salt spray for long periods of time. Purchasing an opaque cover does provide a degree of resistance to the sun’s damaging rays. However, if you really need to be confident that the cover will protect your product from color changes due to fading, or you with to reduce bag deterioration, then the addition of a UVI is a must. Depending on the size, color and type of material, a variable amount of the additive is combined in the production of covers. For each amount there is a corresponding duration assigned to the cover’s shelf life. A 6-month UVI additive and 12-month UVI additives are the most common amounts requested, as most products are either used or sold during the first 12 months. In Joe’s case, the dog food bags are only exposed to the sun during transit. This, coupled with the fact that he has already chosen a white opaque film, will provide ample protection from the sun’s rays.
Now that we’ve narrowed down the materials to be used, let’s discuss measuring and a couple of more manufacturing options. How to measure for a pallet cover, or to determine the cover size required means that we first need to measure our palletized product. A gusseted pallet cover is typically used for 48″x48″ pallets and many other similar sizes. Gusseted covers are very popular as they are form fitted to the product providing a nice clean look. We will cover this type of cover first. Simply measure the height, width and depth of the pallet (for depth number always use the shorter side). Once you have the width (the wider side) measured add 1″-2″ for ease of installation. Next, find the depth and again add 1″ -2″. To find the length of the cover measure the height of the pallet and add 1/2 of the depth. In example: a pallet that measures 48″ wide by 48″ deep by 48″ tall would result in a pallet cover size of 51″ x 49″ x 72″. This size is very common and stocked by many distribution companies. Consider adding a couple inches to the height if you would like the pallet cover to be long enough to cover a portion of the pallet itself. If your cover will be in windy conditions it may be a good idea to order the cover a bit longer, then use a bundling film to secure the bottom of the cover to the wood pallet.
A centerfold cover is commonly used for larger, longer pallet loads. For this cover we again need to find our width, length and height. For a pallet 48″ wide x 96″ long x 48″ high, we will measure the width plus 1/2 the depth, add 1″ – 2″ and use that number for the overall height of the bag. To find the length of the bag we measure the pallet length (96″) then add 1/2 of each side depth (24″+24″) this gives us a length of 144″, we then add 4″ – 6″. This gives us a centerfold cover size: 150″ x 74″. The additional 4″ – 6″ in length are added for ease of installation, as this is needed for larger pallet loads. Most manufacturers’ size capabilities restrict them from producing a gusseted cover for a pallet this size. The centerfold cover differs from the gusseted cover in that it is 2 dimensional and sometimes known as a lay flat bag or cover. Since we are installing a lay flat cover over a 3 dimensional pallet small amounts of extra material remain at the top of both ends. This extra material is commonly referred to as “dog ears” and doesn’t affect the functionality or longevity of the cover. However, if you have a large load and would like a cover without “dog ears” and cannot go with a typical gusseted cover, an M-Fold cover is another option.
An M-Fold cover is needed on large pallets when manufacturing restrictions do not allow a centerfold or common gusset to be used. This cover is termed an M-Fold as it is the look created when the cover is folded in half. We will again need to find the width, depth and height of our palletized product. The length of our cover will again be the length of pallet plus 1/2 of each width and 1″ – 2″ additional inches. The next dimension will simply be the height of the pallet plus 1″ – 2″. The final dimension is one 1/2 of the depth plus 1″ – 2″. For example: a pallet 72″ wide x 96″ long x 72″ high would be 96″” + 36″ + 36″ =172″, then 74″ and 36″. Resulting in a 172″ x 74″ x 36″ “m-fold cover. A common bread bag can help you to visualize the cover. Turn the bag on end and view one end of the bag as the top of your pallet. You will see one open gusset on each side of the bread bag. One negative to the M-Fold cover is its ability to catch and hold water in the exposed gussets. Making a couple of revolutions with a roll of bundling film can eliminate this issue. I have also had customers invert the covers to eliminate this problem. Doing this will improve functionality. However, the m-fold gusset is now exposed, which may or may not be aesthetic concern for you. Since Joe’s palletized dog food bags are placed on a 48″ x 48″ pallet and stacked 48″ high, he will be going with a 51″ x 49″ x 72” gusseted pallet cover. Now that we have the size and type of material, let’s decide on a thickness.
MIL thickness of course refers to the cover’s thickness as it is measured in millimeters. When choosing a thickness, always remember the characteristics of the material being used (briefly discussed earlier). We know that we are using a LDPE and that the load will be secured with stretch film under the cover. We also know that the outdoor exposure and transit Jacksonville pallets times will be minimal. Mil thicknesses of 1 to 6 are most common for one-time use LDPE pallet covers. Most manufacturing facilities can produce polyethylene pallet covers from.0006 to.010 (commonly referred to as.06 MIL to 10 MIL). For Joe’s company, a 1.5 MIL will be used, as aesthetics and marketing are more of a concern than durability. Using a lower thickness may offset the cost of having a more expensive color, printed cover.
When requesting a quote always be sure you’re comparing “apples to apples”. Some manufactures deal only in “full gauge” and others use “industry standard” or “nominal”. If a company uses the latter, a 1.5 MIL product could actually be manufactured +/- 10% which would result in an end product anywhere from 1.35 MIL to 1.65 MIL (usually the lower). A full gauge product is just that, and you will always receive the full 1.5 MIL. This can be checked in house once you receive the product with a micrometer. We now are ready to order a White Opaque Gusseted 51″ x 49″ x 72″ x 1.5 MIL (Full Gauge) pallet cover. Next, let’s discuss Joe’s printing options.
Printing your logo and company info, on the pallet cover can really take advantage of an often-overlooked marketing opportunity. Every manufacturing facility differs in their printing capabilities. However, most have the ability to print on at least one side of the cover in one color. Some manufacturers can produce a two-sided print using several colors. One-sided print is very effective if the pallet is placed with the correct side facing potential customers, i.e. the flat bed trailer, retail store or store yard. The information displayed in the print is really up to the customer. Having a company logo / business card on an electronic file can always speed up the process. No matter what is placed on the cover, make sure to see the final proof and do not sign off on it until you are satisfied.
Pallet cover print is installed by using a “plate” which is a rubber stamp made from your artwork. This plate comes with an additional one-time fee. The plate costs cover any graphic artwork that may be required, as well as the cost of creating the custom rubber stamp. The distance from the artwork to the top and bottom of the cover are selected, as well as the distance between each print. The print is typically applied randomly to the bag meaning that it starts and stops in a different location from one bag to the next. Lead-time for a printed cover can be anywhere from 1-5 weeks depending on the manufacturer and the detail requested. Joe wants a great marketing piece, but is on a budget as well. So he will go with the one side, one color random print. We now have a Gusseted Pallet Cover in White Opaque with 1C1S Random print 51″ x 49″ x 72″ x 1.5 MIL (full gauge). Now that Joe has the vitals selected, how many will he have to purchase?
Minimums on a pallet cover like Joe’s are usually high and may require a large initial investment. Many manufacturers will require a minimum run of at least 3,000 lbs, but some may be willing to run a minimum of 1,000 (often referred to as 1M). All manufacturers think in terms of poundage rather than number of covers. To convert Joe’s covers into poundage, we will need to do some quick math. For a cover 51″ x 49″ x 72″ x 1.5 MIL we add the first two numbers, multiply by the third number, take that number and multiply it by.0015 then divide by 15.
100 x 72 = 7,200, 7,200 x.0015 = 10.8, 10.8 / 15 =.72 pounds per cover
Now, if we know that our manufacturer is dealing in “Industry Standard” or “Nominal” rather than full gauge, we will need to adjust the math a bit. Change the.0015 to.00135 to represent the actual MIL thickness.
100 x 72 = 7,200, 7,200 x.00135 = 9.72, 9.72 / 15 =.648 pounds per cover
If our chosen manufacturer has a 3,000 lb minimum (3M) we divide 3,000 by our full gauge weight,.648. Resulting in a minimum order size of roughly 4,600 pallet covers.
It is standard in the packaging industry for manufacturers to overrun or under-run a product +/- 10%. The final order may have +/- 460 covers. Knowing the conversion to poundage is also helpful when determining the number of covers per roll. 100 bags on a roll at.648 pounds each would put us around 65 lbs a roll, which should be pretty manageable. Smaller roll sizes may require an up-charge based on poundage. Skid weights of 1,200 to 1,700 pounds are most common. If your salesman says his or her custom order minimum is 2 skids, the number of covers can be found by doing some quick division. In this case we’ll say skid weight is 1,400 lbs, so we divide that by the 65 lbs per roll giving us 21.5 or 22 rolls. We then take 22 rolls x 2 skids, 44 x 100 covers per roll = a minimum order of roughly 4,400 covers. Manufacturers will typically have price breaks at 3M, 5M and 10M pounds. Depending on the usage, it may be a good idea to find out how much can be saved by upping the order size. Joe knows that his manufacturer’s minimum poundage is 3M.
Joe! I need you to order 2,000 poly cover-bags for our shipment on the 15th!” the operations manager yells at 3:30 on a Friday afternoon. Being the purchasing agent for his company, it is inferred that Joe knows what a “poly cover-bag” is or what will be the best type, thickness, color or size to…