Imitation metal etching ink screen printing

Imitation metal etching ink screen printing plexiglass products have a clear etching effect, ink film full, three-dimensional sense, and make the product packaging show high-grade, has been cigarette labels, wine labels, cosmetics, health products and other packaging color printing industry Widely used. Can also be used for greeting cards, plexiglass calendars, plexiglass nameplates, plexiglass signs, plexiglass billboards, art paintings and other printing; UV imitation erosion remember screen printing ink can also produce suede and matt effect, can make plexiglass The printed matter is soft, dignified, elegant, and luxurious, and it is difficult to achieve the effect of general ink. For this reason, it has been rapidly promoted and applied.

First, UV curing ink

The ink of this ink is short and thick, in which the diameter of the additive particles is about 15 to 30 μm. After printing, due to the rough and uneven film surface of the ink, the diffuse reflection is reflected in the light and the film surface is dark. In the non-membrane area with metallic luster, under the illumination, the retroreflection is a positive reflection and the gloss is strong, so the area with the film surface is dark and concave, and the area without the film surface is bright and convex. The effect of the two is the opposite. In order to reflect the inherent luster of organic glass, the ink should be transparent, hiding power is not suitable for use. UV imitation metal etching ink is generally a mixture of photosensitive resin and other materials into a light-colored transparent paste; can also be made into color etching ink color. Its composition is as follows.

UV etching ink: main agent (silicone 15 ~ 30μm); binder (photocuring resin or prepolymer, crosslinker, photosensitizer, polymerization inhibitor).

Second, UV imitation metal etching ink screen printing points

1. Platemaking operation quality control

(1) Screen mesh number and thickness of photosensitive film

The etching ink has a certain degree of roughness. If a mesh with a high mesh number is selected, since the mesh is small, the ink does not easily pass or pass through during printing, so that the ink is uneven and a white phenomenon occurs, resulting in a poor etching effect. If you use a low mesh screen, because the mesh is too large, the amount of ink is too much, resulting in paste plate, and also affect the printing effect.

· Matte rough lines: screen 100 ~ 180 mesh; Photoresist film thickness of 10μm or less.

· Scrub mid grain (or ice flower in flower): Screen 150 ~ 250 mesh; Sensitive film thickness 12 ~ 14μm.

· Scrubbing fine text (or ice floret): Screen 200 to 300 mesh; Sensitive film thickness 14~16μm.

(2) As the imitation metal etching ink has a certain degree of roughness, the aluminum alloy frame and the screen printing machine are most used for printing to prevent the pattern from overprinting so that the pattern overprinting is difficult.

(3) Stretching operation

Stretching is used when stretching the net to minimize jaggies and improve plate-making accuracy.

(4) Determination of tension

The size of the tension is directly related to the flatness and print quality of the squeegee-coated photosensitive film. The tension is too large, the screen becomes brittle, the reaction force on the squeegee during printing is large, and the strong screen plate is easy to tear; the tension is too small, the screen is soft, the resilience cannot be generated on the squeegee when printing, and the nap points or India outlets. Only moderate tension can ensure the dimensional accuracy of printing and printing, make overprinting accurate, and the resilience of the screen is good, and the dots are clear and resistant to printing. Under normal circumstances, it is not easy to break.

(5) When making a screen plate, use a solvent-resistant or water-resistant type photosensitive adhesive, develop with water, no pollution, and solvent-resistant photosensitive adhesive, and then print and release the film for reuse.

(6) Due to the thicker photo-resist film, the screen requires a longer exposure time to allow the photo-resist layer to harden completely. At the same time, the development time is lengthened to make the display more effective. The best secondary exposure is to fully cure the photosensitive film and enhance the screen printing resistance.

2. Printing operation quality control

Imitation metal etching inks should be mixed before screen printing. In the printing process, attention should be paid to stirring in order to prevent uneven or uninking of the ink layer. Imitation metal etching inks, like ordinary screen printing inks, can be either screen printing or manual printing. Taking into account the characteristics of the etching ink itself, such as the ink itself is thicker, the printing resistance is larger, the pattern registration requirements are high, and the printing ink layer is required to be uniform, so it is generally preferable to use a screen printing machine for printing. At the same time, attention should be paid to the adjustment of the printing pressure, the squeegee angle, and the screen height in order to control the printing quality and prevent the screen from being damaged prematurely.

(1) Use of additives

· Imitation metal etching ink In the initial printing, do not arbitrarily add other solvents, only when the printing process occurs when the ink leakage does not go on, you can add a small amount of diluent and then stir after printing. Too much of the diluent or stirring is not enough, it will greatly affect its metal texture, but also affect its firmness and dryness on the aluminum gold film. Therefore, when the ink is compounded, various additional materials must be stirred evenly.

• In order to reduce the leveling of the ink on the film surface after printing, no or little dilution or leveling agent is used during compounding to promote the formation of rough and rough film surfaces.

• Use special thinner or industrial alcohol for dilution and cleaning.

(2) The selection of scraper

UV inks cannot use polyurethane-made squeegees. Special rubber squeegees are used.

· Scraper: The hardness should not be too high, generally 65 Shore hardness is appropriate.

Scraper shape: plexiglass is flat, should use a right-angle scraper; substrate is a convex surface, the use of a tapered scraper;

• The length of the squeegee requires that the squeegee be slightly wider than the printed image, so that when the ink is pushed back, there is no residue film on both sides.

· The quality of scraper pressure is an important factor that cannot be ignored. Because the ink is short and thick, the pressure is low, the ink passes through the net is not smooth; the pressure is large, the amount of ink passing through the mesh hole will be too much. Both will affect the print quality and imitation metal etching printing effect, scraper pressure should be controlled at a slightly larger than the pressure of ordinary color ink is appropriate.

The pressure should be the same size when printing, to avoid the pressure due to different sizes, resulting in imitation metal etching ink layer thickness, uneven uneven rough surface.

(3) In the printing process, the wetting state of the imitation metal etching ink should be maintained to ensure that the effect of the printed matter is completely consistent. The degree of wetting is determined based on the user's experience. When the ink is dry, add special thinner in time, and continue to use it after stirring.

(4) Drying of imitation metal etching ink should be selected within the range of 80W ~ 6.4kW of the UV lamp power of the UV light curing machine according to the thickness of the ink and the speed of the photoconductor. The light curing machine must be equipped with a cooling device to prevent thermal deformation of the composite paper when it passes through the curing machine.