The difference between solventless laminating process and other laminating process

Soft packaging laminated film laminating process. There are four common laminating process of soft packaging laminated film: solventless laminating, dry laminating, wet laminating, extrusion laminating. Due to the different requirements of chemical process, economic development and food safety in each country or region, the proportion of the four laminating processes is also different. At present, the Chinese market is mainly solventless laminating, can account for more than 51% of all laminated film laminating process. Since the introduction of solventless laminating in China in 2006, the development in the first 5 years has been very slowly, duo to the high price of equipment and the adhesive, and the lack of professional laminating captains who can operate the laminating machine. Since 2012, the market shares of solventless equipment has expanding year by year, especially after 2015, there has been a blowout growth, by 2018, solventless equipment basically accounted for 51% of the whole laminating equipment, the annual usage of solventless adhesives in China reaches about 5× 104T. The proportion of wet laminating and extrusion laminating is less, which is not introduced here. The following focuses on dry laminating machine and solventless laminating machine.

Dry laminating process is the adhesive coating on a film, after oven drying and then hot pressing with another film fit into a laminated film. It is suitable for all kinds of base material films, base material selection freedom is high, can produce a variety of excellent performance of the laminated film, such as heat resistance, oil resistance, high barrier, chemical resistance film etc. In dry laminating, the control of adhesive coating weight is very important, which affects the quality of laminated material to a great extent. Coating weight is too little, adhesive can not be continuous film forming, spots appearing, affect the appearance quality of the laminated material, and poor adhesion, reduce the boiling resistance and heat sealing strength of the laminated material；Coating weight is too much, not only a waste of adhesive, but also make the film wrinkled and hard, tunnel phenomenon appears, the opening becomes worse, and the solvent is difficult to volatilize, the residual solvent in the adhesive layer is too much, will produce odor. The adhesive coating weight should be determined according to the variety of base material, the use of laminated materials and printing conditions. Usually the coating weight of no printing or small printing area base material is in 1.5~2.5g/m2, the base material such as paper or printing area is large, the coating weight in 2.5~3.5g/m2, boiling resistance base material, the coating weight is in 2.5~4g/m2, aluminum foil  base material used for cooking, the coating weight is above 4g/m2.

Solventless laminating, is the use of 100% solid solventless adhesive, a method of laminating two base materials on a solventless laminating machine, also known as reactive laminating. This process is increasingly used in soft packaging of laminated materials and is likely to become the dominant laminating method in the next 3 years. The most critical technology of solventless laminating equipment is its accurate gluing system, and the most common one is the five-roller gluing system. Take the Polaris series solventless laminating machine gluing system from Trend, a leading manufacture of gluing system in China, as an example: The coating accuracy of Polaris series solventless laminating machine can be solved by adjusting the gap between the rubber roller and the metering roller, controlling the speed ratio between the metering roller and the transfer rubber roller, and controlling the speed ratio between the transfer rubber roller and the coating steel roller. In the traditional operation, these processes need to measure the gap manually by using the feeler gauge, and then adjust the calibration by manual hand wheel to complete the work. This is very testing the professionalism of the operator. In order to reduce the user's dependence on advanced operators and reduce the production risk caused by human factors. The solventless laminating machine uses a self-developed technology system [CCMS],[CWDS]& [PCWD] that allows users to enter the coating range and thickness value on the HMI to complete the work. This friendly way of operation has won the favor of users. At the same time, this is why more and more users are choosing Polaris solventless laminating machines