Talking about Several Methods of Coating on Prints

First, according to the glazing method

1. Single machine polishing (glazing machine)

2. Inline (machine) coating (printing unit + coating machine)

Machines commonly connected to light are: Mitsubishi, Heidelberg, Manroland. In general, the glazing unit is a bit shorter than the printing unit, and some of the two are of the same height.

Second, according to the nature of the oil

1. Ultraviolet (UV) Varnish - Good lightness is not good for the environment

Solid content can be as high as 99% or more; completely rely on UV drying; drying speed depends on the intensity of the light source, irradiation time. In addition, pay attention to the power and service life of the lamp to ensure the normal operation of drying.

· How to adjust the viscosity of UV oil

Adding alcohol can reduce its viscosity, but it is not conducive to drying

Heating is usually performed by the warming device of the coating machine, but some coating machines may not have the heating device.

· The difference between different UV oils

Odor, brightness, abrasion resistance, flatness, coating amount

· General UV coating before the need to hit the bottom (that is, before coating the first waterborne coating), in order to increase the firmness (adhesion) and wear resistance. The base can be used with ordinary water-based varnishes. It is better to use a special base coat varnish.

· In cigarette packaging, UV glazing is widely used, especially in recent years. Usually printed with UV inks, then UV varnish. If printing with common inks, the drying speed will be significantly slower and there may be poor adhesion of the ink and coating oil (ie, peeling of the coating coating).

2. Solvent type (oily) varnish - low cost, with potential safety hazards. The solvent here usually refers to alcohol or other alcohols. Usually the scent of this glazing method is slightly larger, the effect is good and the cost is low. However, the safety risk is high, because the high temperature during the glazing process may cause the explosion of alcohol.

After polishing, it can be calendered to improve the brightness and smoothness of the print surface.

Due to the high cost, it is usually not suitable for online coating.

3. Water based (water based) varnish - environmentally friendly, safe, dry

According to the glazing effect is usually divided into high wear, high light, matt (including matting agent), pressure mirror, plastic (battery, toothbrush packaging box)

4. Cover oil - no need for polishing machine, convenient coating

Its composition is similar to that of ink, and can be printed on paper like ink when used; local glazing is relatively convenient.

Third, according to the glazing part

1. Full version glazing

At present, 80-90% of glazing products are full version glazing

This kind of glazing is relatively easy to operate

2. Local polish

The on-line coating can be achieved by engraving the rubber and digging the liner (the principle of letterpress printing). It can also be done on a coating machine similar to a gravure printing press, and on the three-roller type. Partial coating cannot be achieved on the coater.

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