Brief introduction of the use of special inks and additives (2)

(4) Highlights of the fluorescent process

    Fluorescent inks for screen printing use inks made from fluorescent pigments. Fluorescent pigments are made from fluorescent dyes and synthetic resins. The pigment particle size is between 5 and 15 μm. When using fluorescent inks, note the following points:

1) Since the fluorescent ink has poor light resistance, it is not suitable for long-term outdoor use. Therefore, screen printing used outdoors should not use fluorescent ink. For use on fishing rods, etc., additive 2 should be added.

2) Fluorescent inks are suitable for printing with screens up to 300 mesh, high-tension screens and moderate squeegees.

3) The transfer amount of printing ink on the substrate is 50-60g/m, and its color and light resistance are ideal.

4) When the substrate is a transparent object, white ink is printed before the fluorescent ink is printed, which can improve the fluorescence effect. Can also be printed on paper with high whiteness, the higher the whiteness of the paper, the better the printing effect.

When the fluorescent ink is used for printing the background color, if it can be printed with the same color system, the color saturation can be improved and the light resistance can be improved. When the fluorescent ink is used for printing four color printing products, such as for magenta and yellow printing, it can be obtained. Bright prints. Multi-color printing of the yellow and red plates, with fluorescent inks, results in bright silk screens. Pay attention to the printing sequence to improve the printing effect.

5) Drier is the cause of discoloration, so use it as little as possible. Should not be mixed with other inks, the effect will be reduced.

6) Gloss processing will slightly reduce the fluorescence effect, so you should use a good transparency oil.

Second, the use of additives in the network printing

1, slow agent

The fluidity of the inks composed of high-boiling compounds and special surfactants reduces the viscosity and allows the inks to work normally at different temperatures and environments. It has an excellent effect on the improvement of surface flow properties and can prevent some uncertainties. The resulting defects apply to various solvent-based resin systems. Recommended by experience: versatile, wide application range; release of high-grade ink, such as silver paste, liquid crystal, four packs of CD, etc.; polycarbonate does not crack: long-term storage does not change color, not sink: with solvent-based defoaming, take off Foam function; exceptionally fine, thick, large areas and other special operations smoothly; good leveling, eliminate pinholes, make the screen easy to detach from the printing film, leaving no traces or bubbles; In addition, drying too fast, Easy to cause drawing, if the ink surface is dry fast, the ink is thick, and the drawing phenomenon is particularly serious. In this case, adding a special slow drying agent can effectively inhibit the occurrence of wire drawing phenomenon, such as plastic screen printing ink, metal and glass ink, resistance. Welding ink, character ink and white dry-etching ink, etc., with an amount of 6 to 20%.

Common specifications are: anti-drying agent, anti-blocking agent, concentrate.

2, slow release agent

This product is a colorless, transparent liquid, aromatic flavor, high fat content, low evaporation value, strong opening is a distinctive sign, is an excellent solvent for various inks. This product is widely used in the plastic (PP / PE, PVC, ABS, PS, etc.), metal, glass, leather nylon fabric, rubber, polyester and other plastic printing ink diluted, and printing screen cleaning.

Slow drying agent can adjust the dryness of the ink to prevent it from drying too fast. The inks of different varieties and origins have different drying speeds. In the hot summer, the most severe network is blocked. During this time, slow and heavy agents play an important role, especially for patterns with high precision and fine lines. Or special slow agent, can solve the problem of blocking screens and thinning lines in screen printing.

3, 783 thinner

This product is a colorless, transparent, slightly scented, low-fat liquid. The use of the solvent as a screen printing ink to release and open oil, will not change the ink original performance and quality, suitable for different inks under different conditions of screen printing requirements, reduce the speed of ink in the screen plate to speed up the printed matter The volatilization rate of the surface ink; improve the full aperture of the ink in the screen to ensure the printing quality after ink transfer, this feature is determined by the low evaporation value of 783 and the strong solvent and its eco-friendly material. The use of the solvent as a screen printing ink dilution and pore opening agent can solve the phenomena of clogging, stencil, and indistinct markings on the edges, and can make screen printing products more clear in pattern, without any erosion on the layout, and is an economic, Solvents that can avoid layout problems for a long time have the effect of reducing downtime and improving quality.

As a diluent, it is also called a standard solvent, and it is basically the same as the ink inherent solvent, improving the viscosity and fluidity of the ink. When used, the volatilization rate, safety, and miscibility with the binder should be considered. Therefore, the diluent often varies with the type of ink and the printing environment. In order to adapt to different climates and printing conditions, the same kind of diluent is often divided into three kinds of specifications, namely, standard type, quick-drying type and slow-drying type.

The amount of diluent used in screen printing inks is very limited. Many synthetic screen printing inks can only be diluted by 20% (volume fraction), and glossy inks can only be diluted by 5% (volume fraction). The degree to which the screen printing ink can be diluted depends on the type, type, and grade of the ink and several other factors such as the required brightness, transparency, and the fastness of the ink. The percentage of dilution is usually given by the manufacturer of the ink. In reality, screen printers often use their own experience to determine the consistency of the ink.

Common specifications are: open water; universal solvent; 719 slow dry type; 718 standard type; 717 quick dry type.

4, wash the net water

This product is made of refined solvents and other raw materials, is a colorless or light yellow transparent, non-irritating odor, slightly flavored liquid, has good miscibility with various types of ink, and has strong ability to clean and open holes in silk screen printing inks. The screen pattern is clear and bright, without any erosion on the layout, and it does not affect the screen storage; it does not hurt the skin and improve the printing environment at the same time.

The main purpose: cleaning ink, opening and closing of the picture, quick release and thinning, wiping, repair, replacement liquid, surface treatment agent.

Common specifications are; pore opener/cyclohexanone/alternative liquid/surface treatment agent

The use of steps: moist, care net, ink, clean (matching disposable gloves, wipe paper).

Refer to the use of technology: the remaining ink shoveled into the ink to listen to the use of cotton balls, sweat cloth and other moist surface of the mesh and ink where the ink is dissolved, while at the opposite side of the screen with a text pattern with a net method, will be embedded in the net The ink and pigment particles in the hole are gently lifted out, washed out together with the washing net water and carried away by the wet cloth, so that the layout is free of ink color. The essence of washing the net is to clean the pigment in the mesh (and take the resin with it), which can reduce the amount of washing water and achieve a good work effect.

5, additives

    Additives should have a variety of properties and special effects. To meet these requirements, it is necessary to coordinate the relationship between various properties.

Various additives are used in the production, storage and printing of ink coatings.

The use of additives depends on the ink composition, the method of addition, and the amount of addition. First, the mechanism of action should be fully understood and the choice should be made appropriately. If it is desired to adsorb on the surface, it is advisable to add additives before the surface adsorbs other substances; if certain physical changes are desired, the properties of the coatings and additives should be fully understood and then selected. In addition, if it is necessary to utilize the surface characteristics of the material so that the orientation and separation effects are appropriate, a polymer resin having a good mutual solubility is used. Therefore, the solubility parameters of the resins and additives must be compared before use.

The use of additives is the key to improving the added value of products. However, if you use the wrong method or add too much, it will have the opposite effect. Additives can prevent ink film defects and ills in the ink printing process, giving it special functions and effects. With the development of the ink industry, it is required to develop new products with higher efficacy and better performance. By adding different additives, the purpose of preventing the lack of ink film and improving the efficacy.

Common specifications are: single component, hardener.

6, defoamer

Under normal circumstances, water-based inks often use glycerol; oily inks often use dibutyl phosphate, and polydimethylsiloxane (relative molecular weight of 1200-2700) is useful for water oily inks, the amount of ink added is 3% , Too little can not solve the small bubbles appearing on the surface of the substrate ink layer, too much will affect the adhesion of the ink layer.