Label Materials And Adhesives

Label tapes are available in a variety of colors and widths. Aty first glance it apears we just need to pick the color and width we want, and we're good to go. But there is a lot more to labeling supplies than what meets the eye.

There are hundreds of combinations of "tape" material and adhesive backing. For example there are paper, polyester, cloth and vinyl tapes. There are permanent and removable adhesives. There are adhesives that adhere to rough surfaces and adhesives that stay stuck at low temperatures. Which type of tape and adhesive you choose depends on what needs to be labeled and the environmental conditions the label will need to withstand.

The purpose of this article is to introduce you to some of the more specialized types of label materials. We all know there are labels that work well on file drawers and other clean, dry surfaces. But what happens when you need to put a label on a textured wall or oily pipe? How about labels for laboratory tools that are subject to nitrogen baths, and what about labels you need to see when there is a power failure and the lights go out?

Polyvinyl chloride (PVC), or just "vinyl" label tapes are available in two basic types of vinyl. Calendered and high performance, which is sometimes called "cast vinyl". The difference between them is in how they are manufactured. Calendered vinyls are made by running the vinyl between rollers to flatten it into a sheet. Cast vinyls are made by by a process that is more like pouring paint onto a flat sheet of paper and allowing it to dry into a thin, smooth sheet.

Calendered vinyls cost less to make and lend themselves to large production runs. They are excellent for most labeling applications since most labeling applications involve flat, smooth or gently curving surfaces. The problem with calendered vinyls is that the rolling process builds stress into the vinyl. This stress tends to cause a small amount of shrinkage over time that results in labels that do not adhere well to objects with tight corners, bumps, rough surfaces or troughs.

The process used to make cast vinyl does not result in stress in the vinyl. Thus cast vinyl will remain tightly adhered in corners, over bumps, on rough surfaces and in troughs. This is why it is called a high performance vinyl. The drawback of cast vinyl is that it costs significantly more.

If you need to label oily or greasy pipes, the best option is to use strap-on or wrap-around labels. Instead of using adhesive, these labels are mechanically attached to the pipe. If you have hot pipes, up to 1000 degrees (F), then porcelain enamel strap-on labels are an option.

When it comes to laboratory labeling labels are needed that can withstand both the high temperatures of an autoclave, and extreme low temperatures of a nitrogen bath. Laboratory labels are made from materials such as nylon cloth, polyester, polypropylene and vinyl. Polyester labels are available that can withstand autoclave temperatures up to 260(F) and some nylon cloth labels are suitable for temperatures as low as -320(F). In some cases, such as labeling test tubes, the thickness of the label is important. Standard labels would prevent test tubes from being inserted into test tube racks. Very thin, low profile, vinyl and polyester materials are available that have a minimum impact on the diameter of the test tube. The specific material you select will depend on the temperature range, resistence to solvents, flexibility and label thickness requirements.

Other types of specialty label materials include glow-in-the-dark materials. These labels will glow allowing them to bee seen and read in the dark. Tamper proof materials are available for labeling tools and equipment in a way that leaves evidence if the the label is tampered with. There are repositionable labels that use an adhesive that allows them to be removed and reapplied in another location.

Just as there are many types of label materials, there are also a variety of label adhesives. Thick, "gummy" adhesives are used on labels intended for use on textured surfaces. There are chemical resistant adhesives, low temperature adhesives and even labels that do not have adhesives such as static cling and magnetic-backed label materials.

When purchasing a new label printer it is important to select a printer that can use the types of labeling materials you know you'll need. While some printers have a wide variety of label materials available, while others are more specialized and can use a limited selection of label types.