Laminating, also known as "overmolding", "laminating", "filming", etc., refers to the use of transparent plastic film to be laminated to the surface of printed matter by hot pressing to protect and increase gloss. Laminates have been widely used for the surface binding and protection of book covers, albums, commemorative albums, postcards, product manuals, calendars and maps. Common laminated packaging products include cartons, cartons, tote bags, fertilizer bags, seed bags, self-adhesive labels, etc.
(1) Development history
Lamination technology was born in the 50s and was first adopted by the US Army. China's lamination process was inspired by Japanese calendar cards in the mid-60s, so it was successfully tested on printed matter and soon used in large quantities.
Before 1995, the domestic ready-to-coat laminating machine only had an oil-based laminating machine, and the adhesive it used contained volatile organic substances such as toluene and Tianna water, which had a certain harm to the human body and polluted the environment. Drying and high pressure are also required during lamination, so the power consumption is large, the efficiency is low, and the risk factor is high. With the increasing call for green environmental protection, in May 1996, water-based lamination began to get people's attention, in order to meet the needs of environmental protection, the SFL020 automatic water-based laminating machine was developed in a timely manner, and soon the original version was directly exposed and printed. The successful development of the domestic water-based laminating machine has opened a new page in the history of the development of China's laminating technology and ended the history of the water-based laminating machine completely relying on imports.
(2) Basic introduction
Laminating process is a surface processing process after printing, also known as post-press plastic, post-press laminating or post-press, which refers to the use of a laminating machine to cover a layer of 0 on the surface of the printed product012～0.020mm thick transparent plastic film to form a paper-plastic integration of product processing technology. Generally speaking, according to the process used, it can be divided into two types: instant coating film and pre-coating film, and according to the different film materials, it can be divided into bright film and matte film.
As a way of protecting and decorating the surface of printed matter, lamination accounts for a large share of postpress processing, and if you walk into a bookstore, you will find that most books use this method. This is because the surface of the coated printed matter will be smoother, brighter, stain-resistant, water-resistant, wear-resistant, the color of the book cover is more bright and eye-catching, not easy to be damaged, and the abrasion resistance, folding resistance, tensile resistance and moisture resistance of the printed matter have been greatly strengthened, which protects the appearance of various types of printed matter and improves the service life. It is worth mentioning that the lamination can make up for the quality defects of the printed products to a large extent, and many of the apparent defects in the printing process can be covered after the lamination (especially after the matte film).
Therefore, the laminating process is widely used in all kinds of packaging and decoration prints in China, and various binding forms of books, periodicals, books, calendars, maps, etc., is a very popular surface processing technology for printed products. Laminating technology entered China in the 80s of the 20th century, and because of its many advantages, it became popular all over the country in a very short period of time, and gradually became the darling of the surface decoration of books and periodicals.
(3) Application advantages
Using a laminated cover protects the paper. After the paper is laminated, it can extend the life of its cover, especially for students' textbooks.
Impressions are not easily destroyed. After lamination, it can play the same protective role on the color ** cover, and it is not easy to be worn out. Because of these advantages, it is beneficial for the art editors of the publishing house to create various art designs on the cover. As a result, publishing editors are happy to adopt it, which drives an increase in usage.
(4) The application of laminating process in the field of packaging
Lamination is one of the main processes of post-press processing, which is to bond the plastic film coated with adhesive and paper prints after heating and pressure to form a paper-plastic product, which is one of the common post-press processing processes for paper prints. After the laminated print, due to the surface of a thin and transparent plastic film, the surface is smoother and brighter, which not only improves the gloss and fastness of the printed matter, prolongs the service life of the printed matter, but also plays a protective role in moisture-proof, waterproof, anti-fouling, wear-resistant, fold-resistant, chemical-resistant, etc. If the transparent bright film is used to laminate, the printing color of the laminated product is more vivid, rich in three-dimensional sense, especially suitable for the packaging of green food and other commodities, which can arouse people's appetite and consumption desire. If matte film is used, the film product will bring a noble and elegant feeling to consumers. Therefore, the laminated packaging and printing can significantly improve the grade and added value of commodity packaging.
The laminating process requires the production personnel engaged in lamination processing to use appropriate processing temperature and pressure according to the different properties of paper and ink, so that the adhesive will firmly bond the plastic film and printed paper into a whole of paper and plastic. Laminated product quality standards: the surface is clean, flat, not blurred, good finish, no wrinkles, no blisters, no paper-plastic separation, no powder foil marks. The degree of dryness is appropriate, and there is no sticking to the surface film or paper. The size of the slitting after lamination is accurate, the edge is smooth, and the film does not come out. There is no obvious curling, bending and warping.
In the process of laminating the film, the relationship between temperature, pressure and time when the paper and plastic film pass through the hot pressing mechanism is treated, and the adhesive thickness, glue amount, drying channel temperature, hot roller temperature, mechanical pressure, mechanical speed and other factors can be controlled in the fusion stage, so as to avoid the problems of blistering and poor paper-plastic bonding during lamination.