When we think of printed labels, we almost always think of self adhesive labels. These are labels we see on bottles and products and virtually everywhere in western societies. The sticky rear surface of the labels means that the labels stick to the product or item and once stuck down the labels are difficult to remove. There are some labels where the sticky part is actually on the front of the labels. The obvious example is car registration labels which are attached to the inside of the car window so the labels are protected from harsh weather conditions. Both of these types of printed labels are called permanent labels but not all self adhesive labels are permanent.
There are a variety of uses for removable labels. They too have a sticky background but they are not so sticky so that the labels cannot be removed. Two examples are sign here stickers on legal documents. They can easily be removed. Similarly, small labels on apples and other fruit and vegetables can easily be removed.
There is another type of printed label that is permanent but is not self adhesive. Water is required on the rear surface to enable the label to be stuck onto the required surface. A logical example is single stamps which still must be moistened before they are applied to the envelopes. In fact, as recently as the 1960s, several printed labels needed to be moistened before being applied. The self adhesive gum has only become widespread in the last forty years.
Not all printed labels are attached by moistened glue. However, in your local supermarket, the great majority of products labels are identified by self adhesive labels.
Some printed labels are attached by yarn or twine or are sewed to the items requiring labelling. Many clothing labels are sewn on. Price tags and brand names are often attached by string. You can see these types of printed labels in most clothing stores.
There is also another way of attaching printed labels to surfaces and this is by a process referred to as static cling which involves a static charge so that the labels can be adhered to smooth surfaces such as glass. The material, usually polyvinyl acetate (PVA), is not sticky at all.