Editor's note: Everyone knows that post-press processing is a cosmetic technique for printed products. This process family has many members such as: coating, coating, embossing (arching), hot stamping, hologram stamping, laminating, and so on. Each processing process has its own branches and members according to different requirements. This article only analyzes the role and pollution of the film in post-press processing:

First, the classification of the film

1 according to the process of coating is divided into three types: dry film, wet film, oil film.

2 According to the type of film is divided into OPP, BOPP, PET, Nieuw film and light film, matt film and so on.

3 according to the nature of plastic film is divided into: water film, oil film and pre-adhesive film.

Second, the role of film

The film can protect the print from wear, make the print pattern more bright and full, increase the strength of the print (such as puncture strength, tensile strength), extend the print preservation time (such as photo plastic, do not fade, not yellow , greatly increase the years of preservation).

Third, the application of film

With the continuous improvement of customers' requirements for printing and packaging products and people's understanding and recognition of the film products, the film coating technology has been increasingly applied to various fields of life and production. If you pay attention, you will quickly find a wide variety of film products, such as pictures, color pages, publications, carton boxes, paper boxes, photos, and so on.

In addition, products that are not easily seen by everyone are also a kind of door, such as fertilizer bags, seed bags, handbags, and a large number of packaging items. Not only uses the effect of strengthening the strength of the paper after laminating, but also utilizes the moisture-tight effect of the membrane to increase the performance of the entire package.

Fourth, the pollution of the film

Like other things, there are defects in the film, which is pollution. The membrane fouling is divided into three stages: membrane fouling, product contamination and post-contamination pollution.

1. Process pollution

At present, most of the equipments used in China are home-made equipment. Most of the products below semi-automatic are oil-based films. There are many manual labors, and the distance between personnel and film is close to that of plastics. However, the price of such equipment is low, and it is more suitable for the current labor force. Area.

Used by the manufacturer. The oily film adhesive and its thinner material contain a large amount of chemical diluents such as benzenes and alcohols, which have large odor, strong volatility and toxicity, and have caused health damage to many people in the industry. The report was reported from time to time, and because of its chemical properties, it was extremely flammable. It was a flammable fire in the event of a fire or bright light.

The combination of these two conditions, that is, semi-automatic mechanical plus close manual operation, the operator produces dizziness, headache, skin irritation and other uncomfortable conditions, physical strength is not easy to allergy will feel uncomfortable breathing, fatigue, severe skin erosion, The end of neuritis caused muscle atrophy and even life-threatening. Therefore, the author appeals that companies should not only consider the issue from the perspective of cost, but must comprehensively consider social benefits, personnel health, and take necessary measures to avoid such pollution or mitigate such pollution. Factory managers understand that coated workers are generally not willing to do or do long, even in the case of over-employed workers, working girls, and workers who are not easy to find a job.

Some factories use the methods of frequent substitutions or rotations, and even employ new recruits to enter the factory to work at the polishing machine for a few months to solve the problem of poisoning and harmful substances, but this is not the fundamental solution to the problem. method.

2, product pollution

Benzene and alcohols are highly volatile substances. Most of the volatiles are volatilized during the film coating process and in the short period after the product is formed. However, a small amount remains in the product, along with storage conditions and storage. The time is prolonged and it slowly volatilizes.

The high-speed, high-efficiency production of modern industrial products has led to the rapid transfer of residual substances to consumers. The smell and toxicity of these residual substances have to some extent contaminated the environment in which consumers live and harmed the health of consumers. While the entire world is concerned about the environmental protection, pollution-free, and pollution-free products, this status quo has to be changed.

3, waste pollution

As we all know, paper products can be recycled, and the paper products after the film processing are generally not directly recycled by paper manufacturers, and need to be manually separated and then processed. A new type of white pollution will result if it is directly disposed of. Due to the large number of waste paper recyclers in the country, there is no or no serious problem of pollution of coated paper products. However, the potential existence of such factors does not disappear by itself.

V. Prospects for the development of coating equipment and materials

With the development of science and technology, new materials, new processes and new equipment will continue to be added to the field of dead wood film. With the awareness of environmental protection, health awareness, and the renewal and development of the concept of operators, new scientific and technological achievements will eliminate the products of the old technology, making the film coating process undergo a qualitative change, and the “non-toxic, harmless, and green environmental protection” will become laminated films. The inevitable development trend of the process. For example: water-based film glue, which uses water-soluble high-molecular polyester material and water as a solvent, and is basically an environmentally-friendly product. At present, there is a problem of poor stability of domestic water-based film adhesives, but such defects as those of WDT-3300, WDT-2200, and WDT-1100 produced in Korea have been solved, and they can completely replace the oil-based film adhesive products.

In terms of machinery, laminating machine manufacturers in Guangdong, Hebei, and Zhejiang have successively introduced several semi-automatic desktop dry laminating machine products.

South Korea Yongxin also introduced FLCD-S1020, 1090, 1350, and 1450 four fully-automatic water-based dry laminating machines to the Chinese market. The operation process is fully automated, and the human-machine contact time is greatly reduced, and the use of plastic is non-toxic. Harmless, green and environmentally friendly, these new products have just been introduced by the domestic leading and highly conscious business community, such as Haier Fung Choi, HK and so on. It can be said that "Xiao He was only exposed at the sharp corners and he stood taller."