In addition to having a colorless, odorless, strong gloss, rapid drying, and chemical resistance, the ideal coating oil must also have the following properties.
1 film transparency, no discoloration. Decorative prints to obtain excellent glazing effect depends on the formation of a colorless, transparent film on the surface of the printed sheet, and the graphic does not change color after drying. And it should not be discolored or yellowed due to sun exposure or long use.
2 film has a certain degree of wear resistance. Some glossy prints require some abrasion resistance and scratch resistance after polishing. Because of the assembly line production processes such as high-speed box-making machines, cardboard boxes and packaging machines, and book covers, the surface of prints is subject to friction and must therefore have wear resistance.
3 has a certain degree of flexibility. The glossy film formed on the surface of any type of varnish must maintain good elasticity so that it can adapt to the flexibility of paper or paperboard, and it will not be damaged or cracked or peeled off.
4 Film resistance to environmental performance is better. After glazing, some of the printed matter is used to make all kinds of packaging cartons. In order to be able to protect the products being packaged, the glazing film layer must have good environmental resistance. For example: The packaging of food, cigarettes, cosmetics, clothing and other commodities must have moisture-proof and mildew-proof properties. In addition, the chemical properties of the dried film must be stable. Do not change the performance due to contact with a weak acid or weak base or other chemical substance in the environment.
5 has a certain adhesion to the print surface. Due to the integral density value of surface ink layers, the printability of the printed matter is greatly reduced. In order to prevent the dry and cracked film from drying after use, it is required that the film has strong adhesion, and the ink and ink transfer are used in various types. Accessories have a certain degree of adhesion.
6 Good leveling and smooth film surface. There are various types of materials for printing materials, and the effects of printed graphics, such as the surface absorptivity, smoothness, and wettability, are very different. In order to make the coating on the surface of different products can form a smooth film layer, it requires coating oil. Leveling is good, film surface is smooth after film formation.
7 Printability is wide after printing. After the glazing of prints, it is generally required to go through the post-process processing, such as: molding processing, stamping and electro-aluminum processing. therefore. It is required that the post-printing processing of the coating film should be wide enough. For example, the heat resistance is better. After the electro-aluminization is stamped, no sticking phenomenon can occur; the solvent resistance is high, and the dried film cannot be blisters, wrinkles, and hair due to the influence of the adhesive in the post-processing. Viscosity phenomenon.
In order to obtain the desired glazing effect, in the coating process, the coating of the varnish should meet the following requirements: (1) The coating layer of the coating is uniform, free of blisters, free from bubbles, and free of paint. 2 The coating amount is appropriate, and the coating can be dried and dried at a certain temperature and a coating speed. 3 coating is not affected by printing ink performance, printing image area and integral density value, leveling is good, and has a certain adhesion with the print surface. 4 coating in the calendering, can adhere to the surface of the calender belt, after cooling it can be easily peeled off.
