Corrugated Mailers

Protect your packages from the rigors of shipping by sending them in corrugated mailers. These mailers are boxes and large envelopes made of thick fiberboards. The walls of a corrugated mailer have a fluted inner board covered by one or two flat linerboards. Flutes are S-shaped arches that give a corrugated box its impressive structural strength. Staples® offers a wide selection of these sturdy, protective shipping boxes and envelopes.

Choosing the Right Corrugated Mailer for Your Package
The size of the item you wish to send will determine the type of corrugated mailer you need. You can send slim and small books as well as magazines, photos, and letters in corrugated envelopes. These corrugated document mailers ship flat and are stiff enough to get printed pages to their destinations without creases and are a strong alternative to plain window envelopes. For bigger items, you need larger mailers like corrugated boxes. These are ideal for shipping fragile items and bulky goods. They come in different sizes and styles. Their fluted walls provide ample stacking strength while insulating their contents from moisture, extreme temperatures, and physical damage.

Consider Board Strength When Comparing Corrugated Mailers
Manufacturers use different tests to determine the strengths of corrugated boxes. The most popular are the burst test and ECT or edge crust test. The wall thickness of a box determines its ECT score and burst strength. These then determine the maximum load capacity of the box. A single-walled corrugated mailer has a fluted layer between two linerboards. Boxes with burst strength ratings between 200 and 275 and ECT values between 23 and 55 pounds per square inch fall in this category. Double-walled mailers have two corrugated layers. They are stronger and offer better crush resistance. They can ship heavier items and come in strengths ranging from 200 to 600 pounds while scoring 42 to 82 on edge crush tests. Triple-walled boxes have three layers and can handle significantly higher weights. They are usually large containers for shipping heavy loads stacked on pallets.

What Is the Difference Between Corrugated and Cardboard Boxes?
While corrugated mailers feature fiberboard construction, cardboard boxes are made of paperboard. Regardless of its thickness, cardboard is a paper product while manufacturers use wood chips and shavings for corrugated boxes. A cardboard box also does not have an intermediate layer or fluted core.

What Are the Different Types of Corrugated Box Fluting?
There are five common types of corrugated box fluting designated by the letters: A, B, C, E, and F. An A-flute box has 30 to 36 flutes per linear foot with each one measuring 0.188 inches. B-flute boxes have 44 to 50 flutes that are 0.125 inches thick. Boxes with C flutes are the most common. Their flutes are intermediate in density and thickness between A and B flutes. E and F-flute boxes have more flutes but in much smaller sizes. Pizza boxes, sandwich packaging, and corrugated document mailers fall into these categories.

Are Linerboards Made of Chipboard?
No. Linerboards are usually made of recycled paper and kraft paperboard. Those made of kraft paper often appear brown. They can also come in white if made of bleached kraft paper. Linerboards do come in other colors besides white and brown.