stock or label substrate is the material to which an adhesive layer is applied
with the base being the component that is printed or other processes applied to
create a label. From its very humble paper format there are now many options
including: Polyester, (PET) Polypropylene, Vinyl, (PLA) Polylactic Acid,
Polymide, Polyacrylate, Polyolefin, Polystyrene and of course paper itself.
Each has specific properties such as resistance to decay, moisture, ozone
resistance, heat, chemicals, UV exposure, and more. The adhesives consist of
rubber, acrylic and silicone, which again all have different properties. They
also come in permanent, semi- permanent, removable, ultra removable, freezer
permanent and tamper evident formats.
The release liner (backing) acts as a
carrier for the label. It also protects the adhesive layer, staying with the
label until it is ready to be applied. A release coating is applied to the
liner that will allow it to separate from the adhesive. Although silicone is
the most common release coating, silicone free liners are now available for
clean room environments.
The liner can be in paper or synthetic, which is
becoming more popular. Liners can be butt cut, back scored or have pin feed
holes on the left- and right-hand edges. Many face stocks also have a topcoat
applied to make them more receptive to different inks, coatings and print systems,
not just flexo. The stock can also be glossy, matte or even colored.
then add an over lamination, varnish or other specialty coatings to give the
label even more resistance to environmental conditions, chemicals etc. I have given you a very brief explanation but you probably already
know it is a much more complex subject, and you should
use the expertise of your stock vendor to help you determine what will be best
for you and your customer.