Film coating process

Postpress film, also known as plastic, silicone film. Is a form of decorative processing of printed paper surface. Mainly refers to the use of laminating machine with a thickness of 12 ~ 20 um (PuR glue thickness of 4 m or so) adhesive transparent plastic film and paste the surface of the paste together. Form a paper-plastic product processing technology.

Film coating process development overview

Laminating technology was introduced into China in the 1970s. The first is the introduction of oil-based solvent-based adhesive coating process. As the toluene in the solvent is harmful to the human body and the environment is seriously polluted. Afterwards, it changed the water-based adhesive coating type coating process (ie, the use of aqueous acrylic adhesive). Because of the strong hygroscopicity of the paper and laminating equipment. Film and paper tension is not easy to adjust. Quality problems are difficult to solve.

China began to introduce and use pre-film coating technology from the early 1990s, and introduced advanced pre-film coating equipment from Europe and the United States in early 2000. In terms of environmental protection and product processing quality, this process is much more advanced than previously used oily or water-based adhesives. It is a more advanced film coating process.

Precoat film coating process features

(1) Process environmental protection: The use of EvA hot melt adhesive will not cause harm to the environment and human body; there is no impact of paper and ink on the coating quality. No pollution, low loss. Can process food packaging 7AJ L children's books and other products.

(2) Reliable quality: It is not easy to produce wrinkles and air bubbles. And the separation of paper and film.

(3)Easy to use: Only three steps of feeding, filming, and cutting are applied when coating the film, and there is no glue drying part: the pre-coated film coating equipment is small in size, low in price, and simple in operation.

The inadequacies are. high cost. Film coating material price is about 0.60 yuan / meter. It is difficult to accept general prints. If you can effectively improve the price. The market demand will be great.

At the ChinaPrint 2005 and the just-concluded China International Printing Exhibition, a new type of laminating equipment, the PUR adhesive automatic laminating machine, was exhibited. The device is made by Swiss Stan. Limon company production. And has established a joint venture factory in Shanghai. From the environmental quality cost price, material use and other aspects of comprehensive perspective. PUR adhesive coating type coating equipment is currently the international advanced level of film coating equipment.

it's easy to see. China's coating technology has gone through several stages, that is oily solvent-based glue coating, water-based glue coating and EVA coating. At present, advanced PUR adhesives have been developed into the new stage of coating technology.

PUR adhesive coating process

PuR glue coating process is: preheat PuR glue adhesive storage paper storage film an adjustment pressure (tension) a paper feeding film coating glue automatically remove print dust removal a static one compound one automatic points Cut to automatically pile up the finished product.

PUR adhesive coating process characteristics

(1) Advanced equipment: The use of advanced servo devices is easy to use. Simply set according to the data standard used to obtain ideal results, including adjustment of various rules, thicknesses and amounts of glue. Automatic de-dusting facilitates thorough and automatic removal of static electricity. Smooth delivery, automatic thermal accuracy without error Automatic tension adjustment guarantees stable and reliable coating quality.

(2) Good quality: The high strength of -T-PUR adhesive film generally does not wrinkle, blisters, curl, etc. The equipment has a high degree of automation. It can effectively control and ensure that the tension of paper and film is uniform. The automatic powder removal device can ensure the complete removal of printing dusting; the quality of the automatic thermal cut film ensures that the PUR glue has good fluidity and adsorption capacity. There is no cold and hot glue in processing. When confrontation problems. Can withstand a 40 to 250. The temperature of C has a good adhesion effect for paper with a basis weight of more than 100g/m, because the adhesive layer is thin and uniform. Therefore, after the film is clear, the transparency is good, and the color is more vivid and vivid.

(3) Fast speed: It can reach 60-80 meters per minute, and the split paper can reach ~8000 to 10,000 sheets/hour.

(4) Environmental protection: The use of PUR adhesive has no pollution to the environment and no harm to the human body.

(5) Low cost: Localization of both film and adhesive materials. The price is low and only about 4g PUR glue per square meter, the coating thickness is 3 ~ 4 m, the price is 0 36 ~ 0 39 yuan / square meter. While citing PUR adhesive film coating equipment, in order to better understand and confirm the advanced reliability of this equipment process, I went to Hong Kong in February of last year to apply PuR glue to coating equipment for more than 5 years. Paper Coating Co., Ltd. conducted a field visit to understand the use of the equipment for several years. The company's general manager, Mr. Gu Qifa, was pleased to tell me that although the price was relatively high when purchasing this equipment, it was the wisest decision I made, because it brought us amazing benefits. ”

Film coating market perspective

Since the initial adoption of the oil-based solvent-based adhesive coating process in China, it has caused a lot of trouble for processing companies, and quality has become the most troublesome issue and has not really been solved for more than 20 years. The appearance of the pre-coated film was slightly improved but its cost was high and could not be widely used. After PUR adhesive coating film process appears. Film quality and production costs have a turning point. As far as the current situation is concerned, this type of film-covering equipment is only available from Swiss Stan' Limon Co., Ltd. The higher production cost is only applicable to professional film-covered companies and companies that have large-volume processing business.

Nowadays, there are tens of thousands of domestic film processing enterprises. Nearly 70 percent of the books published each year in the country are printed. About 40 percent of the book covers use the laminating process. Various kinds of packaging boxes are also used extensively to keep them. Exquisite, meticulous appearance is not damaged. Although the problem of paper plastic separation and recovery has not yet been solved, the application of the oil-based solvent-based glue coating technology has not yet been completely improved, but the number of applications of the domestic film coating technology is still increasing. It is understood that some printing and packaging companies are still using a large amount of solvent-based glue coating process. For example, in the Zhejiang area, the owner of a printing company uses a solvent-based glue coating process in order to reduce costs regardless of the health hazards to workers and environmental pollution, and employs a three-year rotation system to evade the burden of responsibility. Because IA has long been exposed to solvent-based materials, it may cause leukemia in 3 to 4 years.) There are many such cases. It can be seen that the elimination of the solvent-based glue coating process is imperative and the relevant departments should strictly implement it.

The long-term practice proves that the lamination process technology has its necessity, but must comply with the general trend of environmental protection. At present, some advanced countries have eliminated the backward solvent-based adhesive coating process using EVA adhesive pre-film coating and higher-level PuR adhesive coating technology. Under limited conditions, China can also gradually free itself from the backward lamination process and join the international advanced technology as soon as possible to move toward environmental protection and high-quality products. This will solve the problems of film quality that have existed for many years and enter the international community as soon as possible. First column

Reprinted from: Printing Technology