The process of coating and calendering in printing process (I)

A. What is glazing?

Glossing is a colorless and transparent coating (varnish) coated (or sprayed, printed) on the surface of a print. After being leveled, dried, and calendered, it forms a thin, uniform, transparent layer of light on the surface of the print. . Coatings include full gloss, partial gloss, glossy gloss, matt (matte) gloss, and special coatings.

B. Why do you need to polish your print?

The glazing is to beautify the printed matter, protect the printed matter, strengthen the publicity of the printed matter and increase the practical value of the printed matter. The surface of the printed surface after polishing is even smoother, resulting in uniform reflection of the incident light and a brighter ink layer. Glazing is the use of varnish for surface coating of printed products. Before the final processing of the prints after printing, take appropriate measures to protect the surface of the paper or paperboard prints. After the printing, the surface is covered with a glossy film. Its application scope includes:

1 The binding of books, such as covers, covers, inserts, and calendars, calendars, advertisements, and promotional samples, etc., can increase the gloss and bright colors of printed materials through polishing.

2 Packing and decorating paper products, such as paper bags, envelopes, trademarks, etc., play a role in beautifying and protecting commodities after polishing.

3 Cultural articles, such as playing cards, postcards, and gold patterns, can resist mechanical abrasion and chemical corrosion when glazing.

4 daily necessities, foods, etc. Such as cigarettes, food, detergents and other trademarks can play a role in moisture, mold.

5 Pressing the copper foil on the hard cover can make the appearance beautiful, and its brightness is very high, very much like gold. If the combination of copper and Kiko is not strong, good adhesion properties can be obtained after polishing.

C. What are the technical requirements for coating oil?

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.

(to be continued)