Below is an explanation of the two types of liners; paper and film. Our team of label professionals would be happy to advise you on the right liner type for your needs, contact us for an expert consultation.
Paper liners are generally Glassine or Kraft based papers. They are processed in a way to provide good tensile strength so they do not snap when they are put under strain either when they are being converted into labels or when they are being wound through a label applicator. They also have a silicon coating applied to the top side which prevents the adhesive that is on the underside of the label from adhering to the paper below. This way the label sandwich (top sheet + adhesive / liner) can be separated easily.
PET or PP liners are used for their extra strength which allows more stress to be placed on the liner without it snapping. They are typically used for high speed and demanding packaging lines. Film liners are also ideal for clear labelling applications, as the smoothness of the film over the paper based liners ensure the adhesive is as smooth as possible prior to application. This gives the label optimum clarity for excellent on pack appearance.