Even in the glueing and gumming process of paper, a machine equipped with air-blades is implemented that distributes a homogeneous layer of adhesive material, thus rendering the paper support easily sticky or self-adhesive.
This technique is not a security feature but does anyhow characterise important value security paper such as post-stamps. It consists in the application through an air-blade of a natural compound (maize starch), which permits the stamp to stick to the paper support once the treated side has been moistened.
The glueing process can basically be divided into two phases: the silicone treatment , where a silicone layer or coating is applied to a substrate of the paper sheet or a film , which will become the protective part that is found on the back of the label. The glueing, i.e. the application of the sticker to the siliconised support which is then coupled to the front piece viz. stickers.