[Vacuum Laminating Machine]What is the principle of vacuum laminating machine Working principle of vacuum laminating machine
Vacuum lamination is to use a special vacuum laminating machine to vacuumize the film and the painting and set it at a certain temperature to complete the lamination. The operation method is complicated, the cost is high, and the picture size is limited to a certain extent, but the mounting quality is high, the picture texture is strong, and it is suitable for photos.
1. Types of lamination and process flow
Lamination is divided into two categories according to different equipment and processes, one is “coating film” , and the other is “pre-coating film”; among them, there are two kinds of light-splitting film and sub-film.
1.1 Instant film coating
Instant film coating is a paper-plastic composite process that uses a film coating machine to immediately stick the film with glue. It is mainly produced by the coating film processing factory or processing workshop. According to the needs, the roll plastic film is coated with adhesive, then dried (slightly) compounded, and the paper film is adhered together to form a film-coated product after being pressed. That is, there are two types of coating equipment, automatic and semi-automatic, and their basic working principles are the same; the process flow mainly includes unwinding → gluing coating → drying → compounding → slitting → finished product accumulation.
① Unwinding
② Glue coating
A, roller reverse type; B, concave type; C, no blade roller extrusion; D, There is a scraper direct type.
③Drying
A, evaporation; B, thermalization; C, solvent exclusion.
④Composite
A, hot pressing roller; B, rubber pressure roller; C, pressure adjustment.
⑤Print input
⑥Recover stacking
1.2 Pre-coating film
Pre-coating film is a It is a process of rewinding the plastic film on the film cloth in advance, and then compounding it with the paper print. The pre-coating film is made by the pre-coating film processing factory, which first coats and rewinds the glue solution according to the different specifications and formats used, and then provides the factory for selection and then composites with the printed paper.
The process flow of pre-coating film is mainly pre-gluing→rolling→gluing coating (hanging cheap type)→curing and cooling→rewinding→slitting→rewinding and rewinding→finished product packaging. Pre-coating machine: temperature adjustment → winding → paper feeding → heating → compounding → slitting → automatic stacking → finished product.
There are three types of precoat films: thermal film, pressure sensitive film and specialty film. Binding is mainly used in two types of thermal films: BOPP, PET (and one is N nylon).
2. The “hot” of the coating film should be “cooled”
That is, the coating film has been popular all over the country in the past 10 years, and the enthusiasm has been obtained. To the extent that it cannot be handled, the film coating equipment is installed everywhere at once; the cover of books and periodicals, regardless of hardcover, paperback, saddle stitching, regardless of the paper quality of the book, is also increasingly used for surface decoration of printed matter. . However, in these years, the quality problem of the instant coating film on the binding has not been solved, and the economic losses caused by it have occurred from time to time; more importantly, the harm caused by the instant coating film has not been sufficiently recognized. Below we briefly analyze the advantages and disadvantages of this process technology.
2.1 saw the “profit” so it was used “hot”
(1) Using the instant coating film as the cover can protect the paper. After lamination, the service life of the cover (or the surface of the printed product) can be extended, especially for students’ textbooks, so the amount is increasing.
(2) The imprint is not easy to be damaged. After being coated with the ready-to-coat film, it can increase the color effect and protect the color printed graphics and text without causing it to be worn. This helps the editors of the publishing house to make various artistic designs on the cover or the surface of the printed product according to their needs, thus also promoting the increase in usage.
(3) The production of coating film is very profitable. In laminating, that is, the cost of coating film production is low, easy to start, and profitable, and enterprises can benefit.
Even if the coating film is “hot”, few people pay attention to the quality problems of the coating film and the influence on the binding quality, which will be further analyzed below.
2.2 Quality problems of the ready-to-coat film
The main problems of the covers and sheets after being coated with the ready-to-coat film are:
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Surface blistering, wrinkling, uneven bending, falling off and separation, difficult to store, etc. These quality problems have not been solved for many years, and the reasons are also various, such as:
①Different types of paper Impact.
②The influence of different ink colors.
③The influence of different climates.
④The influence of environment and conditions.
⑤ Enterprises lack the influence of scientific management.
⑥ The influence of personnel quality.
2.3 Two major hazards of instant coating film
Not only many quality problems are not easy to solve, but more serious is that it has two major harmful effects: intolerable.
①The coating film will cause white pollution
A. The film cannot be corrupted in the air, and it is difficult to recycle and cause environmental pollution.
B. The film-coated adhesive intervenes in harmful objects, which is harmful to human health. Long-term use will seriously harm the health of workers.
②The paper after lamination cannot be recycled, which is a waste of resources
At present, 80% of the source of cellulose in my country’s papermaking relies on recycling waste paper, including paper edge paper wool and so on. Books, booklets, etc. use a large amount of paper. If we use a large number of laminations, especially coating materials, and we cannot separate the paper from the plastic film, then the waste paper that has been covered and the paper edge of the paper will not be able to. Recycling, which will bring immeasurable losses to the country, is actually a waste of resources.
The comparison between the advantages and disadvantages of the coating film is enough to prove that the “hot” of the coating film should be reduced, and it has reached the level of “coldness”.
3. Advantages and future development trend of pre-coating film
Compared with instant-coating film, the advantages of pre-coating film are:
(1) Less pollution and no harm to human body.
(2) There is no difference in paper properties that will affect the quality.
(3) There is no difference in ink color that will affect the lamination effect.
(4) There is no influence of using adhesive with perfect binding.
(5) The laminating machine with pre-coating film is easy to operate and process.
(6) The pictures and texts after processing are more beautiful and the effect is good.
(7) The phenomenon of wrinkles, air bubbles and falling off is basically eliminated.
(8) It has a wide range of uses and can be used for lamination processing other than printed products.
In view of the above advantages of pre-coating film and the fact that the current printing process cannot get rid of laminating technology, it can be concluded that pre-coating film will be the technology developed in the future.
The pre-coating film began to be used in 1989, mainly used in Europe and the United States; it entered Asia in 1996, and at the same time that it entered Asia, Europe and the United States announced the prohibition of the use of the pre-coating film, and the pre-coating film was used instead; Due to the late introduction in Asia, except Japan has basically switched to pre-coating film, other countries such as China, South Korea and some countries in Southeast Asia are in the state of both instant-coating and pre-coating. Since 2000, my country has officially started to use pre-coating film locally. The development situation tells us that the coating process will definitely be eliminated in a very short period of time, and it will be replaced by the pre-coating process technology. Once the pre-coating film is completely replaced by the coating film, and the coating film will be eliminated, it will eliminate a large pollution source for our country and even the world.
Of course, the elimination of the coating film still needs a period of time. This process is first of all a change in people’s consciousness. As long as the harm of the coating film and the importance of the interests of human environmental protection are recognized, it will accelerate The change has improved the surface decoration process of our printed products and articles to a new historical stage, and as soon as possible, it will be in line with international standards and be included in the ranks of the international advanced level.
In order to solve another problem of the lamination process as soon as possible, that is, there is currently no paper membrane separation device in our country, and the paper after lamination cannot be recycled for the time being. We can take two methods for this: One is to seek foreign advanced technology; the other is to appeal according to the characteristics of EVA hot melt adhesive used in pre-coating film, which is a kind of adhesive material with re-adhesion. Paper-plastic separation equipment, in order to completely solve the worries brought about by the lamination process, make my country’s papermaking recycling rate reach the international advanced index, and create a better tomorrow for mankind. The development of post-press technology will be a future of automation, diversification, informatization, digitization, and environmental protection. Let us work together to create this bright future and make more contributions.
Lamination process and its equipment
The lamination process refers to the whole process of laminating pictures and photos, including film selection, lamination Do, cut. It is mainly used for advertising pictures and post-production of wedding photos. The pictures covered with film have high anti-corrosion, waterproof, dust-proof, anti-wrinkle and anti-ultraviolet corrosion properties, which can produce a strong three-dimensional effect and artistic appeal. The cold laminating machine is the main equipment to complete the lamination, and it is also the necessary supporting equipment for the computer inkjet printer and the electrostatic printer. At present, the commonly used equipment for laminating includes four categories: manual cold laminating machine, electric cold laminating machine, self-releasing film cold laminating machine and automatic cold and hot laminating machine, as well as transfer printing equipment.
1. Effect of lamination process:
①Apply the protective film on the picture to improve the strength of the picture and the wear resistance of the surface.
②Isolate the picture from the outside air to prevent deformation and cracking caused by corrosion, humidity and drying of corrosive gases in the atmosphere, fading and discoloration caused by rain erosion and ultraviolet radiation, and keep the picture quality. The bright color lasts for a long time, extending the life of the picture display.
③ Paste the picture on the display board or cloth to make a hanging advertisement picture.
④Press a special mask or sheet on the picture to form a picture with special artistic effects such as bright, matt, oil painting, virtual, three-dimensional and so on.
2. Classification of lamination methods:
The lamination process completed with various materials and equipment is accompanied by the raw materials (consumables) used. ) are divided into several categories according to different temperatures and uses, and the following categories will be introduced.
Cold lamination: The method of laminating the protective film on the surface of the picture by cold pressing at room temperature is called cold lamination. There are also single-sided and double-sided mounted. In terms of operation methods, there are also manual film mounting and self-uncovering film mounting. The cold lamination process has the characteristics of simple operation, good effect and low cost. Currently widely used in advertising light boxes, engineering drawings and post-production of wedding photography.
Thermal mounting: The mounting method of the special thermal film on the equipment heated to a certain temperature (about 100-180°C) is called thermal mounting, which can be divided into single-sided thermal mounting and double-sided thermal mounting. Mounting, because of its good light transmittance and water resistance, good heat resistance and strong hardness, it is suitable for post-production of advertising pictures based on lighting or other occasions. However, the thermal lamination equipment and consumables are expensive, complicated to operate, high energy consumption and high cost.
Similar to thermal mounting, but generally miniaturized. At present, the largest size plastic sealing equipment on the market is 24 inches, which is packaged by heating with special plastic film.
