Introduction to the film covering of the hottest p

Introduction to film coating by printing

release date: Source: China paper

film coating effect is not only related to film coating raw materials and film coating operation methods, but also related to the ink layer condition of the pasted printed matter. The ink layer condition of printed matter is mainly determined by the nature of paper, ink performance, ink layer thickness, image and text area and the integral density of printed image and text. These factors affect the formation conditions of bonding mechanical adhesion, physical and chemical adhesion, and thus cause the change of the surface adhesion of printed matter. Today, China paper will introduce the relevant contents in detail

1. Printing ink layer thickness. Field printed matter with thick ink layer is often difficult to bond with plastic film, and will soon delamination and blistering. This is because the thick ink layer changes the porous surface characteristics of the paper, closes the pores of the paper fibers, and seriously hinders the penetration and diffusion of the adhesive. The four core enterprises controlled by Jian'an aluminum will also be successively established and operated in Jiangnan industrial concentration area. The penetration of the mixture to a certain extent is beneficial to the film bonding

in addition, if the ink layer and the area of the ink layer on the surface of the printed matter are different, the bonding and wetting properties are also different. Experiments show that the surface tension decreases significantly with the increase of ink layer thickness or image area. Therefore, whether it is monochrome printing or multi-color printing, we should strive to control the ink layer in a thin degree and high equipment stiffness

the thickness of the printing ink layer is also directly related to the printing method. The thickness of the ink layer varies with the printing method. For example, the ink layer thickness of lithographic products is about 1-2 μ m. About 2-5 when embossing μ m. Up to 10 when gravure printing μ m。 From the perspective of film covering, lithographic printing is ideal, and its ink layer is very thin

2. Type of printing ink. The printing materials to be covered with film should adopt fast fixing bright offset printing ink. The binder of the ink is composed of synthetic resin, dry vegetable oil, high boiling point kerosene and a small amount of colloid. The synthetic resin molecules contain polar groups, which are easy to diffuse and penetrate with the polar groups in the adhesive molecules, and produce cross-linking, forming physical and chemical binding force, which is conducive to film covering; Fast fixing this light offset printing ink also has the advantage of rapid drying of the ink layer after printing, which is also very beneficial to the lamination. However, it is not suitable to add too much driers when using, otherwise, the surface of the ink layer will crystallize, which will affect the film coating effect

3. Use of ink diluents. Ink diluent is a kind of substance that can lighten the color of ink. The commonly used ink diluents include white ink, Valerie oil and gloss oil

white ink is an ink, which is composed of white ink pigments, binders and accessories. It is commonly used in light color field printing, spot color printing and trademark pattern printing. Poor quality white ink has obvious powder particles, which are not tightly combined with the binder. After printing, the binder will soon penetrate into the paper, and the pigment will float on the paper to hinder the adhesion. This is the reason why some light color field prints are often easily covered with film

self inks should be carefully selected before printing, and try to use self inks that are uniform and fine without obvious particles as diluents

viride oil is a paste transparent body made of aluminum hydroxide and dry vegetable oil binder, which can be used to increase the gloss of the surface of printing materials and has excellent printing performance. However, aluminum hydroxide is light, and will float on the surface of the ink layer after printing. During film coating, an imperceptible isolation layer is formed between the adhesive and the ink layer, resulting in poor adhesion or foaming. Its own drying is slow, but also has the characteristics of inhibiting ink drying, which is also difficult to adapt to film covering

gloss oil is a fast drying diluent from inside to outside. It is a colloidal transparent material mixed and refined from resin, flat vegetable oil, desiccant, etc. it has fine texture, bright conjunctiva, good affinity, and can firmly adsorb polypropylene film on the surface of the ink layer. At the same time, the brightening oil can make the imprinting shiny and the drying speed is accelerated, and the printing performance is good. Therefore, it is an ideal ink diluent

4. Add powder. In order to adapt to multi-color high-speed printing, offsctdruckereien often adopts powder spraying process to solve the problem of dirty back. Dusting is mostly composed of cereal starch and natural suspended substances. The anti sticking effect of dusting is mainly to form an irreversible cushion on the surface of the ink layer, so as to reduce adhesion. Due to the coarser particles, if too much powder is sprayed during the printing process, these particles float on the surface of the printed matter. During film coating, the adhesive is not bonded with the ink layer everywhere, but with this layer of powder spraying, resulting in false adhesion, which seriously affects the quality of film coating. Therefore, if the post press products need to be coated, the amount of powder spraying should be controlled as much as possible during printing

5. The drying condition of the inner layer on the surface of printed matter. Poor drying of the ink layer of printed matter does great harm to the quality of the film. The factors that affect the drying of the ink layer are not only the type of ink, the amount and type of drying agent in the printing process, and the environmental temperature and humidity in the printing and storage room, but also the structure of the paper itself. If the structure of coated paper and offset paper is different, the drying condition of the ink layer is also different

whether it is coated paper or offset paper, when the ink is not completely dried, the impact of film covering quality is adverse. The high boiling point solvent contained in the ink is very easy to make the plastic film expand and elongate, and the expansion and elongation of the plastic film is the main reason for the foaming and delamination of the product after coating. The film covering effect is not only related to the film covering raw materials and film covering operation methods, but also related to the ink layer condition of the pasted printed matter. The ink layer condition of printed matter is mainly determined by the nature of paper, ink performance, ink layer thickness, image and text area and the integral density of printed image and text. These factors affect the formation conditions of bonding mechanical adhesion, physical and chemical adhesion, and thus cause the change of the surface adhesion of printed matter

1. Printing ink layer thickness. Field printed matter with thick ink layer is often difficult to bond with plastic film, and will soon delamination and blistering. This is because the thick ink layer changes the porous surface characteristics of the paper, closes the pores of the paper fibers, and seriously hinders the penetration and diffusion of the adhesive. The penetration of adhesive to a certain extent is beneficial to the bonding of film covering

in addition, if the ink layer and the area of the ink layer on the surface of the printed matter are different, the bonding and wetting properties are also different. Experiments show that the surface tension decreases significantly with the increase of ink layer thickness or image area. Therefore, whether it is monochrome printing or staccato printing, we should strive to control the ink layer to a thinner extent

the thickness of the printing ink layer is also directly related to the printing method. The thickness of the ink layer varies with the printing method. For example, the ink layer thickness of lithographic products is about 1-2 μ m. About 2-5 when embossing μ m. Up to 10 when gravure printing μ m。 From the perspective of film covering, lithographic printing is ideal, and its ink layer is very thin

2. Type of printing ink. The printing materials to be covered with film should adopt fast fixing bright offset printing ink. The binder of the ink is composed of synthetic resin, dry vegetable oil, high boiling point kerosene and a small amount of colloid. The synthetic resin molecules contain polar groups, which are easy to diffuse and penetrate with the polar groups in the adhesive molecules, and produce cross-linking, forming physical and chemical binding force, which is conducive to film covering; Fast fixing this light offset printing ink also has the advantage of rapid drying of the ink layer after printing, which is also very beneficial to the lamination. However, it is not suitable to add too much driers when using, otherwise, the surface of the ink layer will crystallize, which will affect the film coating effect

3. Use of ink diluents. Ink diluent is a kind of substance that can lighten the color of ink. The commonly used ink diluents include white ink, Valerie oil and gloss oil

white ink is an ink, which is composed of white ink pigments, binders and accessories. It is commonly used in light color field printing, spot color printing and trademark pattern printing. Poor quality white ink has obvious powder particles, which are not tightly combined with the binder. After printing, the binder will soon penetrate into the paper, and the pigment will float on the paper to hinder the adhesion. This is the reason why some light color field prints are often easily covered with film

self inks should be carefully selected before printing, and try to use self inks that are uniform and fine without obvious particles as diluents

viride oil is a paste transparent body made of aluminum hydroxide and dry vegetable oil binder, which can be used to increase the gloss of the surface of printing materials and has excellent printing performance. However, aluminum hydroxide is light, and it will float on the surface of the ink layer after printing. During film covering, an imperceptible isolation layer is formed between the adhesive and the ink layer, and then in the up and down operation, resulting in poor adhesion or blistering. Its own drying is slow, but also has the characteristics of inhibiting ink drying, which is also difficult to adapt to film covering

gloss oil is a fast drying diluent from inside to outside. It is a colloidal transparent material mixed and refined from resin, flat vegetable oil, desiccant, etc. it has fine texture, bright conjunctiva, good affinity, and can firmly adsorb polypropylene film on the surface of the ink layer. At the same time, the brightening oil can make the imprinting shiny and the drying speed is accelerated, and the printing performance is good. Therefore, it is an ideal ink diluent

4. Add powder. In order to adapt to multi-color high-speed printing, offsctdruckereien often adopts powder spraying process to solve the problem of dirty back. Dusting is mostly composed of cereal starch and natural suspended substances. The anti sticking effect of dusting is mainly to form an irreversible cushion on the surface of the ink layer, so as to reduce adhesion. Due to the coarser particles, if too much powder is sprayed during the printing process, these particles float on the surface of the printed matter. During film coating, the adhesive is not bonded with the ink layer everywhere, but with this layer of powder spraying, resulting in false adhesion, which seriously affects the quality of film coating. Therefore, if the post press products need to be coated, the amount of powder spraying should be controlled as much as possible during printing

5. The drying condition of the inner layer on the surface of printed matter. Poor drying of the ink layer of printed matter does great harm to the quality of the film. The factors that affect the drying of the ink layer include the type of ink, the amount and type of drying agent in the printing process, and the environmental temperature and humidity in the printing and storage room. In addition, the structure of the paper itself is also quite heavy, and the fixture is mainly designed according to the shape and material of the sample. If the structure of coated paper and offset paper is different, the drying condition of the ink layer is also different

whether it is coated paper or offset paper, when the ink is not completely dried, the impact of film covering quality is adverse. The high boiling point solvent contained in the ink is very easy to make the plastic film expand and elongate, and the expansion and elongation of the plastic film is the main reason for the foaming and delamination of the product after coating

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