Storing label rolls and how printed labels age

A roll lay in the warehouse for six months, and when you put it to work the label sticks badly or the print is faint. Or a printed label faded in two months and the code stopped scanning. Labels have a life of their own, and it depends on how they are stored and used. If you know this in advance, you avoid needless reprinting.

What makes a label age

There are five main factors:

• heat: direct thermal paper darkens all over when warmed, and the print vanishes;
• light: sunshine, especially near a window, bleaches the print;
• abrasion: cartons rub against each other in transport and the print wears away;
• chemistry: grease, hand cream, solvents and some soft films can spoil thermal paper;
• damp and cold: paper swells and the adhesive loses its grip.

The adhesive itself ages too. In a roll stored for a long time it dries out, or creeps past the edge and glues the labels together.

In summer in Tashkent a closed vehicle or a warehouse under a roof gets very hot. Do not leave goods with thermal labels there for long.

Storing blank rolls

Before use, follow these rules:

1. Store in a cool, dry, dark place, away from heaters, windows and direct sun. Take the temperature and humidity range from your supplier's data.
2. Keep the roll in its original packing; re-wrap an opened roll so dust stays out.
3. Do not stack rolls high: the weight of the top ones squashes the lower ones and the label edge deforms.
4. Use the oldest first: write the receipt date on the box.
5. Do not buy a large stock. If your supplier delivers quickly, one or two months of use is enough. For example, if 20 rolls go in a month, two months is 40; a half-year stock of 120 rolls would mostly age in a warm store.

The shelf life comes from the supplier. Add it to the purchase date and do not use an expired roll for important labels.

The life of a printed label

The type must fit the conditions. As a guide:

• a few weeks, indoors, no light (a shipping label): plain direct thermal is enough;
• several months, or cold, damp, abrasion: thermal transfer and a synthetic material;
• a permanent label in the light (shelf, display, equipment by a window): thermal transfer with a protective coating;
• an asset tag that stays for years: thermal transfer on a durable material such as polyester.

A code on thermal paper starts ageing the day it is printed, and in the warm it fades sooner. So do not choose it for the long term.

Conditions at application

A label's life begins the moment you stick it on. The surface should be dry and free of dust and grease; if necessary wipe it with an alcohol wipe and let it dry. Adhesive grips poorly on a cold surface, so both the label and the pack should be at room temperature; labels that work in the cold use a special adhesive. Once applied, press it down firmly with a finger, especially the edges, and leave it alone for a few minutes. Do not put a large label on a creased, ridged or rough surface: the edges lift and it falls off. A label wrapped around a corner damages the code too, so keep the code on a flat part only.

Testing and rechecking

You can see ageing in advance without waiting for it:

1. Print ten labels.
2. Stick five in the harshest place: a sunny window, a hot or cold room, a surface with abrasion. Keep the other five somewhere protected.
3. Once a week scan both groups and note the result.
4. If the print fades, adhesive creeps out or the code reads slowly, change the material.

Even if a label is meant to last five years, this test does not wait five years: the weak spot shows within four to six weeks. Scan permanent labels once a year, for instance during a stock count. Replace any that no longer read or are fading with a new one, keeping the same number.

Conclusion

A label's life depends on three things: storage, material and place of use. Cool, dark storage, the right type and a short test prevent a lot of trouble. The Shtrix team selects a material for your conditions, prints test labels and checks permanent ones from time to time.