On the use of special inks and additives

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

(4) key points of fluorescence process

fluorescent inks for silk printing are inks made with fluorescent pigments as pigments. Fluorescent pigments are made of fluorescent dyes and synthetic resins. The particle size of pigment is 5~15 μ M. The following points should be paid attention to when using fluorescent ink:

1) due to the poor light resistance of fluorescent ink, it is not suitable for long-term outdoor use. Therefore, fluorescent ink should not be used for screen printing brush used outdoors. If it is used on fishing rods, additive 2 should be added

2) fluorescent ink is suitable for printing with silk below 300 mesh, high tension plate and moderate scraper

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

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

when fluorescent ink is used for printing background color, if it can be printed in the same color system, the chromaticity of color can be improved, and the lightfastness will also be improved. When it is used for printing four color prints, such as magenta and yellow plates, bright prints can be obtained. If fluorescent ink is used for the yellow and red plates of multicolor printing, bright silk screen prints can be obtained. Pay attention to the printing sequence to improve the printing effect

5) driers are the cause of discoloration, so try to use them less. Should not be mixed with other inks, the effect will be reduced

6) gloss processing will slightly weaken the fluorescent effect, so bright oil with good transparency should be used

second, the use of additives in pad printing

1. Super slow agent

the fluidity of the ink composed of high boiling point compounds and special interfacial active agents can reduce the viscosity, make the ink work normally at different temperatures and different environments, and have an excellent effect on the improvement of surface flow properties. At the same time, it can prevent defects caused by some uncertain factors. It is suitable for all kinds of solvent resin systems. Experience recommendation: universal and wide range of application; Adjust and release high-grade ink, such as silver paste, LCD, four pack CD, etc; Polycarbonate does not crack: inking does not change color and sink for a long time: it has solvent defoaming and defoaming functions; Special operations such as extra fine, thick printing and large area are smooth; Good leveling property, eliminate pinholes, and make the silk easy to separate from the printing film without leaving traces or causing bubbles; In addition, too fast drying is easy to cause wire drawing. If the ink surface dries quickly and the ink is thick, the wire drawing phenomenon is particularly serious. In this case, the addition of extra slow drying agent can effectively inhibit the occurrence of wire drawing phenomenon, such as plastic printing ink, metal and glass ink, solder resist ink, character ink and white dry corrosion ink, with the dosage of 6 ~ 20%

common specifications include: anti drying agent, anti blocking agent and concentrated liquid

2. Slow release agent

this product is a colorless transparent liquid with aromatic fragrance. High fat content, low evaporation value and strong opening are distinguishing signs. It is an excellent solvent for all kinds of inks. This product is widely applicable to the dilution of printing inks such as plastic (PP/PE, PVC, ABS, PS, etc.), metal, glass, leather, nylon fabric, rubber, polyester, etc., as well as the cleaning of printing plates

slow drying agent can adjust the dryness of the ink to prevent it from drying too fast and blocking the ink. The drying speed of inks from different varieties and places of origin varies. In hot summer, blocking is the most serious. During this period, slow agent plays an important role, especially for patterns with high precision and thin lines. Slow agent or super slow agent must be used to solve the problem of blocking and thin lines in silk screen printing

3, 783 diluent

this product is a colorless, transparent, slightly fragrant and low-fat liquid. Using this solvent as the diluent and oil-water of printing ink will not change the original performance and quality of the ink. It is suitable for silk screen printing requirements of different inks under different conditions, reducing the volatilization speed of the ink in the plate and accelerating the volatilization speed of the ink on the surface of the printed object; Improve the full opening of ink in the plate to ensure the printing quality after ink transfer. This feature is determined by the low evaporation value of 783, strong solvent and its eco-friendly material. That is to say, using this solvent as the diluting and opening agent of printing ink can solve the problems of blocking, plate pasting, unclear ink on the edge, etc., make the printing product pattern clearer, and have no corrosiveness to the layout. It is an economic solvent that can avoid layout obstacles for a long time, and has the effect of reducing downtime and improving quality

as a diluent, also known as standard solvent, it is basically the same as the internal solvent composition of the ink, improving the viscosity and fluidity of the ink. The volatilization speed, safety and miscibility with binder should be considered when using. Therefore, diluents often vary with ink type and printing environment. In order to adapt to different climate and printing conditions, similar diluents are often divided into three specifications, namely standard type, fast drying type and slow drying type

the amount of diluent added in silk printing ink is very limited. Many synthetic silk printing inks can only be diluted by 20% (volume fraction), and gloss inks can only be diluted by 5% (volume fraction). The degree of dilution of silk printing ink depends on the type, type and brand of ink and several other factors, such as the required brightness, transparency and adhesion fastness of ink. The dilution percentage is usually given by the ink manufacturer. But in fact, silk printers often rely on Zhaohui's own experience to determine the consistency of ink

common specifications are: open oil and water; General purpose solvent; 719 slow drying type; 718 standard type; 717 quick drying type

4. Washing water

this product is made of refined solvents and other raw materials. It is colorless or light yellow, transparent, non irritating, slightly fragrant liquid, which has good miscibility with all kinds of inks. It has strong ability to clean and open holes for silk screen printing ink, so that the layout lines are clear and bright, without any corrosiveness to the layout, and its rated pressure is adjusted through the overflow valve, which does not affect the storage of the printing plate; It will not hurt the skin and improve the printing environment at the same time

main uses: cleaning ink, graphic opening; Quick drying and dilution release; Erasure repair; Substitute liquid; Surface treatment agent

common specifications are; Pore opening agent/cyclohexanone/substitute solution/surface treatment agent

use steps: wetting, holding, inking, cleaning (matched with disposable gloves and paper)

refer to the use process: shovel the remaining ink into the ink pad, wet the surface of the hole with cotton balls, sweat cloth, etc. and dissolve the ink where there is ink. At the same time, use the holding method at the place with text patterns on the back of the plate, gently hold out the ink and pigment particles embedded in the hole, flow out with the washing water, and be carried away by the wet cloth. Clean the plate to make it free of residual ink color. The essence of washing is to clean the pigment in the hole (and take away the resin), which can reduce the amount of washing water and achieve good operation effect

5. Additives

additives should have different properties and special effects. To meet these requirements, the relationship between various properties must be coordinated

a variety of additives are used in the production, storage and printing of inks and coatings

the use of additives is related to ink composition, addition method and addition quantity. First of all, we should fully understand the action mechanism and choose appropriately. If you want to adsorb on the surface, it is best to add additives before adsorbing other substances on the surface; If you want some physical changes, you should fully understand the performance of coatings and additives, and then choose. In addition, if it is necessary to make use of the surface characteristics of the material to make the directivity and separation effect appropriate, use the polymer resin that is miscible with it. 3) before inserting the cleaning tool into the barrel. Therefore, the solubility parameters of resin and additives must be compared before use

the use of additives is the key to improve the added value of products. However, if it is used improperly or added too much, it will have the opposite effect. Additives in the ink printing process can prevent ink film defects and disadvantages, and give it special functions and effects. With the development of ink industry, it is required to develop new products with higher efficiency and better performance. By adding different additives, the purpose of preventing the lack of ink film and improving the electromechanical power: 37 kW is achieved

common specifications are: single component, hardener

6. Defoamer

generally, glycerol is often used in water-based inks; Dibutyl Phosphate is often used in oily inks, and polydimethylsiloxane (relative molecular weight) is useful for water-based inks. The addition amount is 3% of the ink. Too little can not solve the small bubbles on the surface of the substrate ink layer, and too much will affect the adhesion of the ink layer

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