Why the instant coating method is still widely used in China. Although the comprehensive performance of the pre-coated film is better than the instant coating method, the current domestic coating industry is the most domestic enterprises. The instant coating process is still widely used. The main reasons can be summarized as follows.
First, the pre-coating film technology started relatively late in China.
Second, the pre-coating film for the production of laminating machine has high technical content, complicated process and large equipment investment. The general enterprise has no ability to invest in the pre-coating film production line.
Third, due to China's surplus labor resources and low labor costs, material costs account for a large proportion of the total cost of the laminating process. The cost of the pre-coating type is higher than that of the coating type, which will inevitably affect its application.
Fourth, most of the equipment produced by domestic laminating equipment manufacturers are instant coating laminating equipment.
Fifth, although the Chinese government emphasizes the environmental protection of the industry, the laws and regulations specifically for the laminating industry have yet to be improved.

Due to limitations in technology, production equipment, and raw materials, pre-coated films (mostly hot melt adhesives) produced by domestic equipment still have quality defects. Since the production process is a process similar to that of the coating film, the colloid is dissolved in an organic solvent, and the rubber is roll coated on the substrate film by a concave anilox roll, so that the solvent volatilization is insufficient, and the odor is generated during operation. After the film is coated, the solvent evaporates and the surface is easy to foam.
At the same time, since the hot melt adhesive is blended by several kinds of polymer materials, in the process of using the laminating machine, the temperature control is not good, which will cause degradation and cross-linking of the high molecular polymer in the hot melt adhesive, so that the surface of the film is poor. Some pre-coated film colloids easily adhere to the outer surface of the substrate, resulting in poor winding. Since the adhesive layer is thin and the surface is not activated, defects such as insufficient adhesion to the printed matter are likely to occur. Since the hot melt adhesive is composed of several kinds of materials, the transparency after coating is significantly worse than that of the low temperature pure resin type precoat film.

The pre-coating film refers to a process in which a plastic film is sized and re-rolled before being combined with a paper printed product. It is firstly applied to the film by the pre-coated film processing factory according to the size of the specification. The glue is applied to the film for re-rolling, and then combined with the printed matter.
The laminating machine laminating film, that is, the laminating film, is a processing technique in which a plastic film is coated with a binder and the paper printed matter is heated and pressurized to bond it together to form a paper-plastic composite product. The film-coated printed matter has a thin and transparent plastic film on the surface, and the surface is smoother and brighter, thereby improving the gloss and fastness of the printed matter. The color of the graphic is more vivid, three-dimensional, and waterproof. Anti-fouling, abrasion resistance, folding resistance, chemical corrosion resistance, etc.

The pre-coating film of the pre-coated laminating machine is limited by the technology, production equipment, and raw materials, and the pre-coated type (mostly hot-melt adhesive) produced by domestic equipment still has quality defects. Since the production process is a process similar to that of the coating film, the colloid is dissolved in an organic solvent, and the rubber is roll coated on the substrate film by a concave anilox roll, so that the solvent volatilization is insufficient, and the odor is generated during operation. After the film is coated, the solvent evaporates and the surface is easy to foam.
At the same time, since the hot melt adhesive is blended by several kinds of polymer materials, the temperature control is not good, which will cause degradation and cross-linking of the high molecular polymer in the hot melt adhesive, and the surface of the film is poor. Some pre-coated film colloids easily adhere to the outer surface of the substrate, resulting in poor winding. Since the adhesive layer is thin and the surface is not activated, defects such as insufficient adhesion to the printed matter are likely to occur. Since the hot melt adhesive is composed of several kinds of materials, the transparency after coating is significantly worse than that of the low temperature pure resin type precoat film.

In recent years, the post-press processing at home and abroad has gradually developed into a refined, which has caused manufacturers to pay attention to the glazing technology in the subsequent processing of printing. There are several types of glazing, such as solvent-based, water-based, UV and EB curing. Among them, water-based glazing and UV glazing are mainly used in domestic and foreign markets.
It can be seen that solvent-type glazing will be eliminated due to large pollution, EB curing glazing is still in its infancy, and water-based glazing and UV glazing development momentum is strong, and will become the leading product in the market in the next few years.