What are the common technologies of laminating machines

Lamination, also known as film lamination, is a processing technique where plastic film is coated with adhesive and bonded to paper or printed matter through heating and pressing, resulting in a paper-plastic composite product. Printed matter that has been laminated by a laminating machine acquires a thin and transparent plastic film on its surface, making it smoother and brighter. This improves the glossiness and durability of the printed matter, enhancing the vividness of the graphics and text, giving them a three-dimensional effect, and also providing waterproofing, stain resistance, wear resistance, folding resistance, and chemical corrosion resistance. With the development of printing technology, there are more and more process methods for laminating. According to the process of laminating, it can be divided into three types: dry, wet, and oil-based. Depending on the raw materials and equipment used, it can be divided into immediate coating laminating and pre-coated film processes. Let's briefly introduce the basic concepts and characteristics of these methods. 1. Immediately apply the coating film During the coating process, adhesive is first applied to the film, followed by hot pressing. However, the production process is prone to fire hazards. 2. Pre-coating film This process greatly simplifies the laminating procedure as the laminating equipment does not require a binder heating and drying system. It is also very convenient to operate, as it can be turned on whenever needed, providing great production flexibility. Additionally, it has no solvent odor and no environmental pollution. More importantly, it can completely avoid faults such as bubbles and delamination. The products have extremely high transparency, with broad application prospects and implementation value. The pre-coated film structure consists of a substrate and an adhesive layer. The substrate is usually made of PET and BOPP films. Considering material costs and processing technology, most pre-coated film substrates choose BOPP films with a thickness of 12-20 microns, and the adhesive layer has a thickness of 5-15 microns. Depending on the processing equipment and process conditions, adhesive layers of different thicknesses are selected. The adhesive layer is divided into hot melt adhesives and organic polymer low-temperature resins. The difference between the two is that hot melt adhesives are made by blending and modifying several materials, including main adhesive resin, tackifier, and modifier, while organic polymer resins are single low-temperature copolymers of polymers. Due to limitations in skills, production equipment, and raw materials, pre-coated films (mostly of hot-melt adhesive type) produced by domestic equipment still exhibit quality defects. The production process relies on a technique similar to that of immediate coating films, where the adhesive is dissolved in organic solvents and applied onto the base film using a concave anilox roller. This process can lead to insufficient solvent evaporation, resulting in off-odors during operation and use, as well as blistering on the surface after coating due to solvent evaporation. Additionally, because hot-melt adhesives are blended from several polymer materials, improper temperature control during use can cause degradation and cross-linking of the polymer chains within the adhesive, leading to poor film appearance. Some pre-coated films tend to adhere to the surface of the base material, resulting in poor winding. Due to the thin adhesive layer and the lack of surface activation treatment, defects such as insufficient adhesion to printed materials are prone to occur. Because hot-melt adhesives are blended from several materials, the transparency of the coated film is significantly worse than that of low-temperature pure resin pre-coated films. 3. Water-based laminating It refers to the method of processing the appearance of printed materials to enhance their surface glossiness, strength, and aesthetic appeal. To evaluate the quality of laminating, factors such as brightness, strength, and adhesion should also be considered. Water-based wet laminating is favored by customers due to its high strength, ease of recycling, and pollution-free characteristics. 4. Applying a thin film on a curved surface It is a brand-new transfer printing technique that can handle workpieces with complex shapes and is suitable for different materials. Moreover, it significantly enhances the added value of products due to the vivid patterns and colors. This technique involves a specially chemically treated film, which, after being printed with a specific color pattern, is placed flat on the surface of water. The pattern is then uniformly written onto the surface of the product using water pressure, while the covering film automatically dissolves. After cleaning and drying, a transparent protective coating is applied, and the product now exhibits a completely different visual effect. The laminating process can be divided into cold (cold press) laminating, hot (hot press) laminating, and liquid laminating methods based on the conditions of heat, pressure, and materials. image