Analysis of Defects and Countermeasures in Water-soluble Thin Film Printing

Water-soluble plastic packaging film is mainly used for packaging of products used in water, textile packaging, water transfer printing, as a temporary carrier for the production process of wigs and embroidery, agricultural seed tapes, washing bags, etc. Food packaging, disposable packaging such as physiological cotton and toilet paper towels, solid water slow release packaging, temporary protective film, and production of composite high-barrier packaging materials. However, there are not many applications for printing water-soluble plastic packaging films, mainly in the areas of product packaging and water transfer printing. Water-soluble films used in other fields generally do not require printing.

Textile packaging

Printing water-soluble plastic packaging film is mainly used for product packaging, and the inner packaging generally does not need to be printed.

The outer packaging of food is mainly used for disposable packaging of dried fruit, fried and fried foods.

Water transfer printing

Water transfer printing utilizes the pressure and activator of water to transfer the graphic on the water transfer carrier film to the substrate. Its greatest feature is the realization of curved surface printing. Therefore, it is also called cubic printing or 3D printing.

First, the application of water transfer printing

Mainly used in automotive interior products (such as steering wheel, dashboard, etc.), electronic products (such as telephones, mobile phones, etc.), household goods (coffee table, vases, etc.), daily goods (such as luggage decoration, insert pen holder, etc.), indoor Building materials (such as security doors, etc.), shoe materials (such as heels, shoes, etc.).

Second, the characteristics of water transfer printing:

Water transfer printing can be applied to a variety of complex shapes; adaptable to a wide range of substrates, such as: plastics, metals, glass, ceramics, etc.; there are more than a hundred kinds of conventional patterns available, covering the design of natural peach wood, marble and special effects. Lines; According to the customer's own design patterns, lines, as a printing film.

Third, the basic process flow of water transfer printing

The basic process flow of water transfer printing: carrier film cutting → spray activator → water pressure transfer → washing process → drying process → varnish protection → heat curing.

Fourth, the water transfer printing process may produce defects and countermeasures

Water-soluble film is mainly gravure, screen printing or offset printing. Because its main component is PVA, it is a flexible packaging material. Therefore, various defects and countermeasures produced during the printing process of flexible packaging materials such as PE, PVC and other plastic packaging films are suitable. In water-soluble PVA film. At the same time, PVA film has its own characteristics, which are described as follows:

First, good anti-static properties, therefore, its printing performance is better than other films, water-soluble film polarity, good printing performance, using ordinary printing methods can be printed clearly without the need for EDM;

Second, because it is different from other films, the water content in the film changes with the temperature and humidity of the environment, and its mechanical properties also change. Therefore, the elasticity changes greatly, which can cause misregistration in the printing process, graphic distortion, etc. defect.

In response to this problem, our countermeasures are as follows:

First, try to keep the temperature and humidity of the printing processing environment constant, make the change of the water content of the film as small as possible, thus make its performance keep stable;

Second, on the back of the water-soluble film is attached to the non-deformable paper (usually pearl paper), so that it has the non-extensibility of the paper, so that it can solve the expansion and contraction of the water-soluble film in the printing process, effective printing. At present, foreign countries have developed such water-soluble film (commonly known as water-soluble coating paper film), Hunan University of Technology is also studying such a water-soluble film production process and equipment, will soon achieve industrial development;

Third, in the design of printing water-soluble film, we must carefully conceived, in-depth consideration, making the design of the printed water-soluble film has a repeating structure, or ambiguous graphics, or completely non-repeating patterns, so that even if the printing process, graphic It is irrelevant if there is a change in shape. The strange effect of "unintentional" will occasionally appear when it is not sure.

Conclusion

With the development of production and social progress, the application of printing water-soluble film on packaging will become more and more widespread, and the printing requirements for water-soluble film will also become higher and higher, but with the progress of technology, water-soluble film is The quality problems existing in the printing process will also be gradually solved.

â–  Wen/ Hao Xihai Li Xiaojuan Wu Xurui

Reprinted from: Guangdong Packaging