The key technologies of Laminating process are mainly in several aspects, such as laminating temperature control, laminating pressure control and laminating peed control and so on.
Laminating temperature is the primary factor when Laminating, because laminating film use hot melt adhesives and the temperature determines the molten state of hot melt adhesive as well as the permeability and diffusion capacity of hot melt adhesive molecules to the BOPP film, print ink layer, paper, etc.. Raising the temperature will help to enhancement of adhesion strength, but the film will shrink and the surface of products will brighten, bubble and wrinkle if the temperature is too high. According to practical experience, laminating temperature should be controlled between 70 ~ 100 ℃.
The surface of paper is not flat, and only in the appropriate pressure, the molten hot melt adhesive will be completely cover the surface of printed products, then the laminated products will be bright and good bonding. If the pressure is small, the bonding is not strong and if the pressure is a little large, it will help to improve the bonding force between film and paper products. However, if the pressure is too large, the products are willing to wrinkling and the surface of the rubber roller is easily injured or deformed and the service life of rubber rollers will be reduced. As the pressure increases, the touching pressure between the rubber roller and the heating roller increases and the loading of the shaft and bearing of two rollers as well as the loading of transmission system will increase, which leads to increased wear. Therefore, the too large pressure will affect the use life of the whole machine.
In production, the pressure should be adjusted according to the different paper. If it’s the loose paper, the pressure will be larger, otherwise it should be less. As the experience, generally the appropriate laminating pressure should be set to 8 ~ 25MPa.
The laminating speed Determines the melt time of the adhesive on the heated roller and the touching time of film and paper. If the speed is slow, the heated time of adhesives on BOPP film will be long relatively and the laminating time between BOPP films and paper will be long, then the bonding will be good. And if the speed is fast, the heated time of adhesives on BOPP film will be short relatively and the laminating time between BOPP films and paper will be short, then the bonding will be bad. The production speed of Domestic laminating equipment is generally controlled between 5-30m/min.
The above is a simple analysis to the three key technologies of laminating: laminating temperature, laminating pressure and laminating speed, but the adjustment among the three should be based on the equipment, the different lamination product and the different types of films. Then you can get high-quality lamination products.
Special printed products means those printed products with large printing area. thick ink layer , deep color, paper of large moisture content, paper of large size. Laminated on such printed products, the laminating parameter should be controlled as follow:
Laminating Temperature ：95～110℃
Laminating Pressure ：16一25Mpa
Laminating Speed ：5—10m/min
Contact Person: Ms. Cherry Chen