Analysis of types and characteristics of commonly

Analysis on the types and characteristics of commonly used paper for cigarette packs (III)

v. aluminum foil paper

aluminum foil paper is also called aluminized paper and aluminum spray paper, and its surface is attached with a very thin layer of metal aluminum. The cigarette bag printed with aluminum foil paper is gorgeous and exquisite. Because the commonly used colors are gold and silver with metallic luster, it conforms to the noble aesthetic psychology of Chinese tradition. At present, the vast majority of high-end cigarette packs are printed with aluminum foil. Aluminum foil paper is divided into aluminum foil card paper, label paper and cigarette lining paper according to the difference of base paper. According to the different surface patterns, it is divided into: pattern holographic aluminum foil paper, plain holographic aluminum foil paper and ordinary aluminum foil paper. According to the different processing technology, it can be divided into paper plastic composite aluminum foil paper, transfer aluminum foil paper and direct plating aluminum foil paper

paper plastic composite aluminum foil paper is generally 12 ~ 20 μ M PET film is vacuum aluminized and colored, and then compounded with paperboard (glass paperboard or white paperboard) through a compounding machine. This process has both thin film and aluminum, so the cost is high. However, due to the use of high gloss pet, the effect of aluminum spraying is remarkable, and the surface gloss is bright, which shows the grade. Therefore, it is still used in some high-end cigarette packs at present. However, due to the high cost and non environmental protection, the voice of opposition is getting higher and higher, and less and less is used

transfer method is a widely used aluminum foil production process at present, and its process is shown in Figure 1

because the aluminum foil layer on the surface of aluminum foil paper is evaporated under high vacuum, the large roll of cardboard or high gram weight coated paper contains high moisture and air inside the paper, which makes it difficult to vacuum and exhaust in the aluminum plating cabin, and it is not easy to achieve the high vacuum required for aluminum plating. At the same time, the discharge of a large amount of water in the paper has greatly changed the physical properties of the paper, and it is difficult to achieve the original physical indicators even after the moisture regain treatment after aluminum plating. Therefore, the direct plating method is mainly used for the production of low gram weight label paper and cigarette lining paper. Its process is shown in Figure 2

due to the different production processes of the above three kinds of aluminum foil paper, the physical characteristics of the paper used in large-scale engineering projects are mainly determined by the formula, and the physical characteristics of the device, the non main control system, and the non key station sheet are also very different

paper plastic composite aluminum foil paper has the highest surface smoothness and the brightest visual luster. Because the metal aluminum is attached to the PET film, the metal aluminum is firmly attached, and there will be no aluminum loss during printing. At the same time, due to the existence of the PET film, the stiffness and toughness of the paper are improved, and the post press processing, which is extremely cheap, can only be used for two years, has better performance

for transfer method aluminum foil paper, the metal aluminum foil layer is transferred and adhered to the paper surface from pet. No matter what kind of paper, its surface smoothness cannot reach the level of nijpet film surface. The gloss of transfer method aluminum foil paper decreases, and cracks are easy to appear when the film is cut and indented after printing. Therefore, in order to achieve good results in the printing process of transfer aluminum foil paper, its characteristics must be considered in the design and plate making, and the glittering metallic luster of this paper must be shown as much as possible

the design pattern should not choose the hue with large area and strong coverage, but should be printed with ink with good transparency. For example, transparent yellow is often printed on the silver aluminum layer, which can present gold with metallic luster. For transfer aluminum foil materials, ink bursting is easy to occur at the 90 degree or 180 degree fold of the printed product. It is best not to print ink at the fold to make up for the lack of folding of the material

the printing adaptability of aluminum foil paper is relatively special. Its surface metal aluminum structure is relatively tight, and there is basically no gap, which is similar to the mirror. Therefore, the surface of aluminum foil paper does not have the absorption performance like ordinary paper. It is a non absorbent substrate, and cannot use fast drying, bright and fast curing offset ink, or special ink for offset printing of synthetic paper. There is still liquid solvent on the surface of aluminum foil after inking, which will make the printed matter very easy to stick and dirty, resulting in a large number of waste products. Therefore, special inks must be used to avoid dirt and improve drying performance. UV ink is the best choice for aluminum foil printing. Because UV ink does not contain solvent components, it is irradiated by UV lamp after printing. Therefore, the ink is immediately cured and dried, and has the characteristics of firm adhesion of the ink layer and high gloss. Therefore, in recent years, many cigarette bag printing enterprises have added six colors +uv ink curing and drying device +uv glazing offset press, which is mainly used to solve the problem of aluminum foil printing

(author/wangweixin Beijing duopai packaging and printing equipment Co., Ltd.)

source: printing magazine