Several screen printing processes for high-end packaging boxes (Part 1)

Several screen printing processes for high-end packaging boxes (Part 1)

With the introduction and development of screen printing equipment and materials, the domestic screen printing technology has made great progress. With its own unique advantages, screen printing is favored in the field of packaging and decoration, and its status and role cannot be ignored, especially in tobacco, wine, and gift packaging. At present, the most widely used screen printing processes such as imitation metal etching, ice texture, refraction, etc., the printed packaging boxes are colorful, elegant and luxurious. Imitation metal etching screen printing process

The so-called imitation metal etching screen printing is to use the screen printing method to print imitation metal etching ink on the printing materials with metallic luster such as gold and silver cardboard to obtain a kind of smooth metal that has been etched, engraved or frosted. Unique visual effects.

1. Imitation metal etching screen printing plate

(1) Selection of wire mesh. The wire mesh with high tension, uniform mesh and small expansion rate should be used, and plain weave thin polyester wire mesh is generally used. Since the particles of the imitation metal etching ink are relatively coarse, the diameter is about 15-30 μm, the screen should be made of 180-240 mesh/inch, and the mesh width can reach 60-90 μm.

(2) Selection of the screen frame and stretching the net. The screen frame should choose an aluminum alloy screen frame with good strength, heat resistance, corrosion resistance, lightness, durability and no deformation. In order to ensure the quality of the stretched net, a mechanical stretcher or a pneumatic stretcher can be used to stretch the net, and the stretched net tension should be controlled between 16 and 18N/cm.

(3) Apply the photosensitive solution. The photosensitive adhesive can be made of diazo photosensitive adhesive. The coating tank is mostly stainless steel. Pour the photosensitive liquid into the tank to account for about 1/2, tilt the stretched screen plate at 70°, and the coating tank is in contact with the lower end of the screen surface. And slowly lift it up, and coat it along the mesh surface from bottom to top. Note that the speed is not too fast to avoid foaming of the photosensitive liquid and pinholes on the film surface. After that, the screen plate was turned upside down and coated again, and then dried in a drying oven at 40°C. After drying, apply the same method to the squeegee surface of the screen for 2 to 3 times until the film thickness reaches 10 to 30 μm.

(4) Printing. It is to close the film surface of the positive picture on the photosensitive adhesive surface of the screen plate, and put it into a vacuum printing machine for exposure. The exposure light source can be selected from 3kW iodine gallium lamp, and the exposure time can be determined according to the specific situation.

(5) Development. Immerse the exposed screen plate in water for 1 minute to make the non-photosensitive film absorb water and expand, and then use a spray gun with a pressure of 3.5 ~ 5.5kg/cm2 to spray water from both sides of the screen plate to develop until the mesh of the non-photosensitive graphic part is completely open. until transparent. After that, drying and retouching are required.

2. Imitation metal etching screen printing

(1) Printing materials. The surface of the substrate should be a metallic glossy surface, such as aluminum foil cardboard, film surface of anodized aluminum hot stamping. In screen printing, the glossy film surface is in sharp contrast with the uneven rough surface of the printing etching ink. Under the sunlight, the greater the contrast between the two, the stronger the imitation metal etching effect is. This effect is other printing materials. unattainable.

(2) Imitation metal etching ink. This ink is widely used in high-grade tobacco, wine, tea, cosmetics, gifts and pharmaceutical packaging. After printing this ink on the surface-coated vacuum coated paper (commonly known as gold and silver cardboard), it will produce an effect similar to the metal etching sand surface, so it is also called frosted ink. Originally, the ink could only be imported from Japan and South Korea, but now it has been fully localized, and its quality is comparable to imported products. It is one of the most widely used types of ink in screen printing for cigarette packs and wine packs. The ink is a transparent viscous liquid with a grayish-white appearance. It is divided into three specifications: coarse sand, medium sand and fine sand. It has good printability.

Now, the special ink for imitating metal etching screen printing is UV curable ink, which is composed of photopolymerization resin, photopolymerization initiator, pigment, auxiliary agent and polymerization inhibitor. When curing, the curing light source can be a metal halide lamp with a power intensity of 120W/cm, a focal distance of 10cm, and a curing speed of 10 to 15 m/min (different light sources and lamp distances are different). The characteristics of imitation metal etching ink are fast curing speed, not easy to seal the net, and easy to clean.

Ice screen printing process

Ice flower screen printing is to print ice flower ink on gold and silver cardboard. After UV curing, the surface of the printed product will show a crystal clear, dense and dense "ice flower" pattern, which sparkles under the illumination of light, just like on the glass window in winter. Blossoming ice flowers. Ice flower screen printing can make the packaging of cigarettes, wine and gifts more novel and unique.

1. The main points of screen printing

(1) The wire mesh is generally made of 100-300 mesh/inch monofilament polyester wire mesh. Among them, 100 ~ 180 mesh / inch screen printing ice flower effect is the best. The lower the number of meshes, the rougher the pattern of the ice flower effect; the higher the number of meshes, the more delicate and delicate the pattern of the ice flower.

(2) The screen tension is 16-20 N/cm, and the film thickness of the coated photoresist is generally 12-14 μm.