Book surface decoration processing UV coating

The surface decoration of books and periodicals belongs to the category of post-press processing for exquisite decoration of books and periodicals. It is generally covered with film, hot stamping, embossing, calendering, embossing, glazing, etc., from environmental protection, cost, efficiency, innovation and practicality. The use of the operability and many other aspects of comparison, the author believes that UV coating is the preferred tool for printing surface decoration processing, printing counterparts in the technical transformation and the introduction of new technologies worthy of attention in a post-printing process of practical production process. UV glazing technology has been widely used since the invention in the 1960s until the end of the 20th century. UV glazing of paper products in China is growing at a high rate of more than 20% per year, and its application prospects are very broad.

Uv coating advantages

UV coating is the processing method of UV coating after curing by UV light and has the characteristics of rapid curing and low temperature curing. At present, the gloss processing on the surface of printed materials (such as various book magazine covers, labels, packaging, etc.) is generally UV glazing, which greatly replaces the tendency of plastic film and solvent-based glazing.

(1) UV Varnish is almost solvent-free, with low organic volatile emissions, reduced air pollution, improved working environment, and reduced risk of fire. It is an environmentally friendly product.

(2) UV Varnish has a strong affinity for grease type inks and adheres firmly. After glazing, no calendering is required. It can be completed in one pass. The glazing surface is firm and uniform, with no blistering, no curling, and no curling. UV glazing has been widely used in aluminum foil and aluminum foil paperboard printing, book printing, magnetic card printing, trademark packaging printing, metal printing, and further surface decoration processing of food, medicine, cigarette packets, stickers and other packaging and printing fields. in.

(3) After the UV coating process, the color is obviously brighter than other processing methods, and the cured coating has a wide range of re-art processing effects, such as refraction and matte. Crystal, wrinkles, etc., coating thickness up to 1 ~ 1.5mm. Visual art has a strong sense of contrast, and the coating is abrasion-resistant, chemical-resistant, and has better stability.

(4) UV Varnish has a high active ingredient, less volatilization, a saving in dosage, and a high glossing efficiency. The coating amount of coated paper is usually 2 to 4 g/m2, and the cost is about 40% to 60% of that of the water-based coating. It is also possible to avoid the defects that often occur in the coating process, such as edge-to-edge, blistering, and Wrinkle, delamination, broken film, snow spots and other phenomena. After UV curing, the printed products are not easy to be adhered, have no static electricity, and are resistant to certain high temperatures. After curing, they can be stacked, die-cut, hot stamped, etc., which is beneficial to the post-press processing line operations. Because it has the characteristic of instant curing by UV light irradiation, compared with other coating processes, UV curing is more thorough, without any evaporation or solvent-borne contaminants. Varnish is 100% cured, and is more conducive to various types of printing equipment. High speed online production.

(5) It can effectively recycle and solve the problem that the paper base of the traditional printed surface coating film cannot be recovered in time and the film is difficult to be naturally degraded.

(6) UV glazing is simple and easy. UV Varnish is suitable for the price, and the supply channels are convenient. At the same time, the production process is simple, the equipment covers an area of ​​small, easy to use, and the technical requirements for operation are not complicated. If you use the old-fashioned offset presses that have been eliminated, you can easily modify or purchase screen printers for local UV coating. The cost can be controlled within 10,000 yuan, which is an immediate and rewarding project.

UV Varnish Composition and Type

The main components of UV inks include photopolymerization prepolymers, photoinitiators, diluting monomers (reactive monomers), organic pigments, and additives.

The photopolymerization prepolymer is a main component of UV varnish, and generally acrylic resin, acrylic polyurethane, epoxy acrylic resin, acrylic polyester, modified acrylic polyester and the like are generally used. The photopolymerization prepolymer is a UV ink binder, which determines the adhesion, abrasion resistance, chemical resistance, solvent resistance, hardness, viscosity, and curing speed of the UV varnish.

Photoinitiators are reactive organic groups that initiate cross-linking of photopolymerized prepolymers. The curing process of UV varnish is a cross-linking process of a polymer, and the photoinitiator is excited into a radical or an ion under the irradiation of a certain intensity of UV light, and then the interpolymer energy is transferred to make the prepolymer in the ink, The active monomers form charge transfer complexes, and these polymers are continuously cross-linked, thereby allowing the UV varnish to undergo a photo-curing reaction from a liquid state to a solid state. In the course of this reaction, there is substantially no solvent volatilization, which is conducive to environmental protection.

Because the UV varnish curing is a photochemical cross-linking reaction, the curing speed is fast, the energy consumption is small, the product is glossy, and the color is beautiful. As the optical oil film is formed by cross-linking of polymers, it is oil-resistant, wear-resistant, water-resistant and solvent-resistant, and has the advantages of long-term storage and stable performance.

There are many types of UV Varnish, not only all kinds of conventional Varnish (such as high light, ordinary, matt, semi-Asian, extinction), but also ice, scrub, refraction, foam, wrinkles, embossed, gemstones and other Varnish For artistic processing again.

Reprinted from: Printing Information