Thursday, July 16, 2015

Bag Basics

Not all bags are created equal. There is a whole world of materials, sizes, thicknesses, imprints and closure styles.  Knowing basics bag specifications will help you choose the right bag for your packaging need.

Define the Need
The first step in choosing the right bag is to define what the packaging needs to do.  Some bags are strictly utilitarian keeping something contained. Others have safety in mind to protect from harmful materials. Still other bags are used for marketing to advertise a brand. Many times a bag has multiple purposes. Defining what you need the bag to do will help determine the right style.

Bag materials can be paper, plastic, vinyl, fabric, nonwoven and other specialty materials such as PET (recycled water bottles) or PEVA (vinyl with recycled content).  Determining the best material depends on the goals for the bag.  If you need FDA approved, biohazard protection then a bag made from virgin plastic with tight seals is required.  If the goal is something 100% biodegradable and recyclable, then paper would be your likely choice.  The bag substrate is an easy choice once you determine what you need the bag to do.

The size of the bag is determined by the size of what is to be contained.  Generally bags are measured width by length. Bags can have side or bottom gussets which is typically stated as the depth.  There are industry tolerances in bag measurements. Most bags are produced on moving equipment that makes exact precise measurements impossible.  Keep this in mind when determining the specs for your bag.

The thickness of the material can influence the strength of the bag.  For paper, thickness is called weight and is measured in pounds. In plastics and vinyl, thickness is call gauge and is measured in mils which is one thousandth of an inch.  Nonwoven material is measured in GSM or grams per square meter. Generally the greater the thickness the more durable the bag.

Closure and Carry Style
Bags are created to keep contents inside and to transport those contents.  Styles vary from open-ended, zip close, drawstring, tamper evident, and all sorts of carry handles. Consider what is going inside the bag, how secure you need those contents, if the bag is reusable, and how the bag is being transported. 

Printing on a bag might include important warnings, instructions, or offer additional advertising. There are a variety of imprint types. Screen printing takes a screen of the art and ink is flooded over that screen to produce the imprint.  Hot stamp imprints use heat and pressure to apply a foil imprint. Ink printer take a rubber pad plate dipped in ink to imprint the logo.  There are also heat transfer and digital printing options. The bag material will determine what type of imprinting options are available. Imprinting involves additional costs such as art services, set up, imprint plates or a per bag imprint charge.

There you have the bag basics. An understanding on your options makes you an educated buyer. Have a bag questions? Ask the experts below!