Self-adhesive labels are an important printing variety widely used in commodity packaging, logistics transportation, and various identification. In self-adhesive label printing, lamination is a very critical link. It can protect the label surface, enhance durability, and improve aesthetics, thereby improving the service life and quality of self-adhesive labels. This article will introduce the lamination process and method of self-adhesive labels after printing, aiming to help readers understand different lamination methods, technical points, and material selection, as well as how to master the correct lamination process to ensure quality and reliability.
The Role of Label Lamination
Label overlays are used to protect labels from environmental damage such as water, UV rays, abrasion, etc. By adding a clear protective film to the surface of the label, you can extend the life of the label and keep its appearance clear. Label laminations can also enhance label durability and prevent images or text on labels from fading over time. Laminates also provide additional protection, ensuring labels are not damaged during shipping and storage. All these advantages can enhance the customer experience, thereby enhancing brand awareness.
Laminated Material
The lamination of self-adhesive labels usually uses the following materials:
Polyester Film (PET): This material is durable and water-resistant, and it provides high-quality printing of images and text.
Polypropylene film (PP): Lightweight and highly transparent, this material provides a durable protective layer. Composite fully transparent PP film is currently the most widely used material. The reason is that PP is low-cost and more durable than several other materials.
Polyvinyl Chloride Film (PVC): This material is economical, but relatively less environmentally friendly than PET or PP materials.
Polyethylene film (PE): This material is soft and suitable for label lamination on curved or irregular surfaces.
Due to cost requirements, the coating of paper roll materials is basically replaced by glazing technology. In the label industry, when the varnish cannot meet the brightness and matte requirements, lamination is the most direct way. We can choose the appropriate lamination material according to different application scenarios to ensure the label gets the best protection and durability.
Laminating Methods
Label lamination methods are usually divided into sheet-fed lamination and roll material lamination. The sheet-fed paper is laminated on the laminating machine, and the roll material is laminated on the laminating station of the label machine or on a special laminating machine. The two coating methods are described below:
- Sheetfed Laminated
Sheetfed lamination involves placing labels on a sheet of lamination material and using heat and pressure to bond the lamination and label together. This method is suitable for situations where individual labels need to be laminated, such as when the labels are of different sizes or special handling is required for the labels. Sheetfed lamination can be performed using manual or automatic laminators.
There are two ways of laminating sheet-fed self-adhesive labels, namely instant coating lamination and pre-coating film lamination.
1)The compounding process of instant coating compounding is as follows: firstly, the adhesive is coated on the surface of the roll BOPP film, and the solvent in the adhesive is volatilized through the drying device, and then the sheet paper is combined with the roll film at the compounding station. Composite, the two become one under the extrusion of the hot roller, and the film coating process is completed.
2)Pre-coated film composite refers to pre-coating a layer of adhesive or laminating material on the surface of the composite film. There are two types of films, hot melt adhesive type and pressure sensitive type. The laminating machine is equipped with a heated embossing roller, and the pre-coated film is in contact with the sheet of paper during lamination. Under the action of the hot pressing roller, the adhesive is melted, so that the film and the paper are bonded into one. If you use a pressure-sensitive composite film, you can turn off the heating power supply and only rely on pressure to composite.
- Roll Material Lamination
Roll material lamination is to print the roll material film and label together, and then pass them together through the laminating machine for heat and pressure treatment. This method is suitable for the production of a large number of labels, which can improve production efficiency and reduce costs. Lamination of web materials can be done in batch or continuous production.
Web lamination is usually divided into two types: bottomed paper composite film composite and bottomless paper composite film composite.
1)Backing paper composite film lamination refers to compounding a layer of backing paper on the front or back of the roll paper, and then coating a layer of adhesive or laminating material on the backing paper, and then sticking the label on it. Backed paper composite film lamination is a traditional lamination method, which has been replaced by the process of using bottomless paper composite film in recent years.
2)The laminating principle of the composite film without the bottom paper is basically the same as that of the composite film with the bottom paper. The backing paper film is rewound by the surface smoothness (surface tension) of its own material to replace the backing paper. After the adhesive is bonded to the surface, it can be peeled off without leaving any glue traces. The material used for the bottomless paper film is generally a low surface tension BOPP film. The cost of bottomless paper film lamination is low, and it is the most widely used lamination material at present. The advantage of bottomless paper composite film composite is that it can improve production efficiency, reduce waste in the production process, and at the same time improve product quality.
Of course, no matter which lamination method is used, a protective layer can be formed on the surface of the label to protect the label from environmental damage.
In self-adhesive label printing, lamination is a very important step, because it can make the label more beautiful, durable, and adaptable. The correct lamination method and material selection can ensure the quality and service life of self-adhesive labels. Therefore, printing manufacturers and users should pay attention to the selection of suitable lamination methods and materials, and carry out quality control to ensure the final quality of self-adhesive labels.
