Paper Label Printing Process (I)

Before discussing the label printing process and its processing method, we must first understand what is the printing of the sticker, and it is different from the traditional label printing. Self-adhesive labels are also called self-adhesive labels, timely stickers, sticky notes, pressure-sensitive paper, etc. They are made of paper, film or special materials, coated with adhesive, and coated with silicon protective paper as a kind of backing paper. Composite materials, and after printing, die-cutting and other processing into a finished product label. The application requires only peeling from the bottom paper, and can be applied to the surface of various substrates with a single press, and labeling machines can also be used to automatically label the product on the production line.

When we talk about the process of label printing, we must also understand the basic structure of the adhesive material as a printing material and the function of each part. The structure of the self-adhesive material is composed of three parts: surface material, adhesive and backing paper. However, from the point of view of manufacturing process and quality assurance, the self-adhesive material consists of seven parts:

1, surface coating

Used to change the surface properties of the face material. Such as improving the surface tension, changing the color, adding a protective layer, etc., to make it more acceptable ink and easy to print, to prevent dirt, increase the adhesion of ink and to prevent the printing of graphics off. Surface coating is mainly used for non-absorbent materials, such as aluminum foil, aluminized paper and various film materials.

2, surface material

That is, the surface material is a material that accepts the printed graphic on the front side, receives the adhesive on the back side, and is finally applied to the attached article. In general, any flexible deformable material can be used as a self-adhesive material fabric, such as commonly used paper, film, composite foil, all kinds of textiles, thin metal sheet and rubber and so on. The type of face material depends on the final application and the printing process. Surface materials should be able to adapt to printing and printing, have a good ink, and have enough strength to accept a variety of processing, such as die cutting, waste, slitting, punching and labeling.

3, coating

The same as the surface coating, it is just coated on the back of the face material. The main purpose of the coating is:
(1) Protect the surface material to prevent adhesive penetration.
(2) Increase the opacity of the fabric;
(3) increase the adhesive force between the adhesive and the surface material;
(4) Prevent the plasticizer in the plastic face material from penetrating into the adhesive, affecting the adhesive properties, resulting in a decrease in the adhesive force of the label and the label falling off.

4, adhesive

The adhesive is the medium between the label material and the bonding substrate and acts as a bonding agent. According to their characteristics can be divided into two kinds of permanent and removable. It has a variety of recipes for different face materials and different occasions. Adhesives are the most important ingredient in adhesive material technology and are key to the application of labeling technology.

5, release coating (coated silicon layer)

That is, the surface of the base paper is coated with a silicone oil layer. The application of the silicone oil can make the base paper a surface with a very low surface tension and a very smooth surface. The function is to prevent the adhesive from sticking to the base paper.

6, bottom paper

The role of the bottom paper is to receive the release agent coating, protect the adhesive on the back of the face material, support the face material, enable it to die cut, waste and labeling on the labeling machine.

7, back or back

Back coating is a protective coating on the back of the backing paper to prevent waste, and the adhesive around the rewinded label is attached to the backing paper. Another role is to make multilayer labels. The back printing function is to print the registered trademark or pattern of the manufacturer on the back side of the backing paper, which serves as a propaganda and anti-counterfeiting effect.

(to be continued)