If you ship items regularly, you may have wondered “What is a poly bag?” A poly bag refers to any bag made of plastic, although it most often refers to polyethylene (PE), the most common type of plastic used worldwide.
Many types of poly bags are suitable for packaging and shipping items. Knowing the purposes for different poly bag types is critical to assess and optimize your shipping expenses.
But before we cover what a poly bag is, let’s cover these points:
- Poly bags are lightweight and inexpensive alternatives to cardboard boxes.
- Most poly bags manufactured today use recyclable materials, limiting the environmental impact.
- Each type of poly bag fulfills a particular purpose and is suitable for different applications.
- Choosing the right poly bag for your items helps optimize packaging and shipping expenses.
Why Use Poly Bags?
Poly plastic bags are excellent alternatives to cardboard boxes for small, soft and non-fragile items. Using poly bags instead of boxes also produces less waste and reduces the need for filler, such as packing peanuts, cardboard spacers, dunnage air bags or scrap paper.
They are the ideal solution for shipping books, magazines, printed media, apparel or fabric products. Poly bags are also an excellent solution for shipping items already packaged in sturdy boxes, such as DVDs, packaged cosmetics, shoe boxes or boxed video games.
Custom Poly Bags
Some poly bag types can be customized with different colors and printed logos. Poly bags not only keep your product secure during shipping but are a fantastic way to feature your brand on the packaging, making your business stand out from the competition.
Many retailers and eCommerce companies opt for custom-sized poly bags that precisely match their product’s dimensions. Shipping items in these bags helps the customer feel like they are purchasing a high-quality, upscale item.
Custom poly bags can help make an excellent first impression on new customers and even help you build a loyal customer base, but it may prevent you from taking advantage of blind drop shipping.
What is blind drop shipping? Blind drop shipping fulfills eCommerce orders via a third-party wholesale seller. This method works increasingly well for many eCommerce businesses, but it is important to consider your shipping method and the type of packaging you plan to use. While drop shipping offers several advantages, you typically cannot use custom poly bags or other branded packaging, as the drop shipper supplies the packaging materials.
Poly Plastic Bags Can Protect Your Goods While in Transit
Lay-Flat Poly Bags
Lay-flat poly bags are the simplest type of poly bag available. They are available in a wide range of sizes and thicknesses and are suitable for many products. Lay-flat poly bags feature a single opening sealable via heat, tying, stapling or taping.
When selecting the right size lay-flat poly bag, consider the width, length and thickness (gauge). Width and length are measured in inches, whereas thickness is measured in mils. A mil is 1/1000 of an inch or 25.4 nanometers. Most flat poly bags feature gauges ranging between 1 and 6 mils. For comparison, a typical credit card measures approximately 31 mils. Heavier gauge poly bags are better suited for items that need additional protection, such as steel tools or hardware with sharp points.
Whether you use small or large poly bags depends on the item size. Ensure you select the dimensions most appropriate for your products. The most common gauge employed is 2 mil. Two-mil bags are suitable for packaging most small retail items, from food to clothing.
Typical lay-flat gauges and intended applications include:
- 1 mil: Extra-lightweight bags suitable for packaging durable or non-fragile items. They are economical, extremely light and easy to tear and open. They only provide minimal protection, shielding the items from dust or fingerprints.
- 1.5 mil: Economical poly bags suitable for packaging food products, such as bread, sandwiches, and vegetables, as well as paper items, documents, stamps and other light, non-fragile items.
- 2 mil: Standard-weight bags, offering a good balance between low cost and protection. Two-mil bags have the broadest possible applications, suitable for anything except sharp or heavy objects.
- 3 mil: Medium-weight bags, suitable for packaging parts, tools, hardware and any product requiring additional resistance to tearing and puncturing.
- 4 mil or 5 mil: Heavy-weight bags, suitable for sharp or heavy items, such as large tools, bearings, nails, screws, bolts, nuts and other parts featuring sharp edges or points.
- 6 mil and higher: Industrial-grade poly bags, suitable for the heaviest objects, such as steel tools and parts, soil, jagged rocks or construction materials.
Flat poly bags are also available on continuous rolls holding between 500 and 2,000 bags, depending on your selected dimensions. Rolls are ideal if you need large quantities of bags in a single size. Poly bag rolls are typically pre-cut for easy separation, making them convenient to use.
Gusseted Poly Bags
Gusseted poly bags are similar to lay-flat bags but are manufactured with a foldable pleat, making the bag wider and giving it a square, flat bottom. When fully opened and standing up, a gusseted poly bag resembles an open-ended plastic box.
Gusseted poly bags are ideal for packaging items with irregular dimensions. Using a gusseted poly bag eliminates the “dog ears” phenomenon, squaring the bottom of the packaging and resulting in less wasted space.
Gusseted poly bags are available in the same range of widths and lengths as lay-flat poly bags, and they may also be ordered individually or on rolls of 500 to 2,000 units.
Resealable Poly Bags
Resealable poly bags are reusable containers suitable for packaging or preserving a wide variety of small items. They are also known as reclosable bags, secure bags, baggies and various popular trademarked names.
The key feature of resealable bags is their sealable opening, designed for easy opening and reclosing, so you can reuse it as many times as needed. There are different sealable top designs, from simple grip-actuated seal tops to more complex and durable zipper closures.
Like standard poly bags, resealable bags are available in both flat and gusseted models in various dimensions. Although resealable poly bags are not available as rolls, they are inexpensive and available in lots of 500 to 3,000 units, depending on desired sizes.
Most resealable poly bags are between 2 and 6 mil thick. Because of these bags’ reusable nature, you won’t find models less than 2 mil in thickness.
Specific models of resealable bags called markable bags (or white block bags) have an opaque, writable white section so you can label the content using a marker.
Markable bags are ideal for organizing, displaying and shipping small parts. They are typically between 2 and 4 mil thick and are suited for long-term storage.
Shipping a Larger Product? Use Large Poly Bags
Anti-Static Poly Bags
Anti-static poly bags are similar in shape and function to regular lay-flat and gusseted bags, using an anti-static additive compound in their construction designed to protect sensitive electronic components from static electricity. They are ideal for packaging and shipping items such as printed circuit boards, hard drives or graphics cards. Anti-static bags are typically colored differently from other types for easy differentiation.
There are multiple types of anti-static poly bags, including:
- Standard anti-static poly bags that protect the contents from static electricity. They are between 2 and 6 mil thick and wrinkle-resistant and distinguishable by their pink coloration.
- Resealable anti-static poly bags that perform the same duties as standard models but are reusable and resealable. These models are also pink, featuring a red seal top.
- Static-shielding bags, available with either open tops or zip tops and recognizable by their opaque blue exterior. These bags are typically 3 mil thick and feature an outer layer protecting the contents from electrostatic discharges. Specific models feature interior cushioning for additional protection.
- Conductive poly bags, black opaque poly bags using 4 mil sheets of carbon-loaded polyethylene. This material forms a Faraday cage, offering protection against humidity, corrosion, ultraviolet light (UV), electromagnetic interference (EMI) and radio-frequency interference (RFI). Most conductive poly bags follow military specification requirements (MIL-DTL-117H Class A) and are suitable for the most sensitive electronics.
Polypropylene Bags
Polypropylene (PP) is a high-clarity transparent plastic used to present and showcase its contents while also protecting them from moisture and corrosion. It is also robust and flexible.
The food industry uses PP bags to package perishable foods, such as dried fruit, nuts, candy or confectionery, because they allow consumers to clearly see the products inside. Polypropylene also features high resistance to vapors, chemicals and organic solvents, keeping the contents fresh.
PP bags are typically available as lay-flat resealable containers, ranging between 1.5 and 2 mil thick.
Bubble Wrap
Bubble wrap is a type of transparent packaging featuring an array of air pockets that absorb impact, abrasion and rough handling, preventing the items inside from breaking.
Bubble wrap is also water-resistant and reusable, as long as the bubbles aren’t popped or damaged. These protective properties make bubble wrap well-suited for protecting fragile items during shipping.
Bubble wrap is rarely used alone when packing items. It is typically used as additional padding inside another packaging container, such as cardboard boxes, large poly bags or mailer bags.
Bubble wrap is available in sheet rolls or manufactured into lay-flat bags, either open-ended or re-sealable. Some types of bubble wrap even have anti-static properties, identical to standard anti-static poly bags.
Individual bubble sizes range from roughly 0.25 to 1 inch, with 0.5-inch bubbles being the most common. Smaller bubbles are suitable for most purposes, whereas larger bubbles are ideal for packing and protecting larger objects.
Mailer Bags
Mailer bags, also called postal poly bags or poly mailers, are poly bags designed to meet USPS requirements for postal packaging use.
Mailer bags are an excellent alternative to cardboard boxes for shipping smaller or soft objects. They are less expensive and lighter, which reduces your shipping expenses. They do not require filler materials or spacers.
There are several types of mailer bags, each suitable for various applications:
- Standard lay-flat poly mailers are opaque bags available in various dimensions, ranging between 1.7 and 3 mil of thickness. They are best suited for shipping clothes, fabric items and thin, pre-boxed or pre-packaged objects.
- Transparent lay-flat poly mailers let you see the contents and are ideal for shipping printed media, such as books, magazines, catalogs or brochures.
- Gusseted poly mailers or expansion mailers are ideal for shipping bulkier objects, such as sets of books, large books or bundles of DVDs or video games.
- Bubble-lined mailers are lay-flat mailers featuring an internal bubble wrap cushion. They are ideal for protecting fragile objects during transport.
- Returnable mailers are unique resealable mailer bags featuring two self-sealing openings, allowing the customer to re-seal the same mailer bag in case they wish to return the product.
- Extra-long mailer bags are suitable for shipping long, narrow, non-fragile products, such as rolls of wallpaper or fabric. This type of mailer bag is typically 4 mil thick, water-resistant, tear-resistant and puncture-resistant.
Furniture Bags
Furniture bags are large plastic bags designed to cover furniture such as sofas or tables. This poly bag type uses 1 mil polyethylene (PE), which has water-resistant properties and protects furniture against dust, debris and stains.
Furniture bags completely encase furniture and are suitable for storage, warehousing and shipping of furniture and furniture elements. However, they offer little-to-no protection against scratches or dents. Consider padding your furniture bags with bubble wrap or cardboard sheeting when packing fragile furniture such as mirrors or glass tabletops.
Environmental Impact of Poly Bags
Many industries and businesses, including retail and eCommerce, rely on poly bags for packaging, branding and shipping their products.
However, a 2009 study, A Study on a Poly-Bag Manufacturing System: Preliminary Analysis and Simulation, found environmental regulations have long pushed back against manufacturing single-use plastic bags, encouraging the use of recyclable or eco-friendly alternatives instead.
Today, most poly bags use recyclable materials, such as high-density polyethylene (HDPE) or low-density polyethylene (LDPE). Certain types may even use 100 percent recycled materials or environmentally friendly, biodegradable materials in their construction.
The Takeaway
Understanding the answer to “What is a poly bag?” and the different types available helps you make more informed decisions about the shipping materials you use to safely deliver your products.
Efficient management of your packing materials saves you money on shipping expenses, and your customers will also appreciate your efforts to reduce waste and avoid unnecessarily large or bulky packaging.
Air Sea Containers offers a wide selection of packaging, packaging materials, storage solutions and accessories for all your packing and shipping needs. If you have questions about our products, call us at (866) 272-9880 or send us an email at sales@airseacontainers.com.
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