Ink and screen printing

Screen printing ink has a variety of brands at home and abroad, quality and price are not the same, regardless of imported ink, or domestic production of ink, are inseparable from the intrinsic quality of their products, only the correct understanding of the inherent quality of silk screen printing ink, will not be Misleading advertising and usage habits can correctly select products with good quality and reasonable prices. According to my many years of practical experience, I will introduce the following for the reference of my silk screen colleagues so as to avoid unnecessary losses.

1. Ink concentration, hue, tinting strength and printing

Ink density is the same as the color saturation, the amount of printing per unit area. Simply speaking, in the case of the same mesh number screen, how much area can be printed per kilogram of ink when reaching the same color density. In general, the company can print about 35m2 of ink at 250 mesh. The color tinting strength can be compared with the color rinsing method. For example, when the ink reaches the same concentration, the amount of rinsing agent required is compared. The ink viscosity is not equal to the ink concentration. Under normal circumstances, the viscosity is high and the ink concentration is relatively high.

Ink hue: different manufacturers have their own different positioning colors, in the visible light range, each band is a color, so the color variety can be quite a lot, but the general manufacturers have determined their moderate positioning color as the product positioning color, for the user to choose Therefore, the user must select the closest color according to his own printing sample to adjust to meet his own use requirements.

2. Ink gloss, hiding power, transparency and printing

One of the main appearance characteristics of printed samples is the glossiness of the printed matter, which depends on the gloss of the ink itself. A professional manufacturer selects excellent raw materials. Therefore, the ink species produced have a very good gloss and can also be used to produce matting products. The gloss can be observed with the naked eye and can also be measured with a gloss instrument. Inappropriate raw materials, or adding a large amount of thinner, will produce a very low gloss effect. Ink luster is also affected by the printing substrate and printing process. For example, if the printing surface is covered with a layer of varnish, the gloss of the printed material will be enhanced, the surface of the printing substrate will have a smooth reflection effect, and the gloss of the printed material will also increase.

Covering Power and Transparency The ink itself has a pair of relative indicators. The hiding power is good, and the ink transparency is poor. Manufacturers will generally locate their products with various hiding powers and transparency to meet the different needs of users. Increase the hiding power, in addition to the choice of good hiding power of ink, you can also add appropriate amount of white ink to increase the transparency of the ink. In addition to selecting a good transparency ink, you can also add the amount of varnish.

3. Ink fineness and printing

The ink fineness requirement should be different according to the applicable scope of printing, and we are not accustomed to think that the finer the ink fineness, the better. If the fineness is too fine, the hiding power of the ink will be reduced, which will affect the inherent quality of the ink. The purpose of the fineness must be a reasonable number of screen meshes in order to smoothly pass the ink. For chromatography printing, the finer the ink fineness, the better.

4. Ink flow and printing

The fluidity of the screen printing ink affects the printability of the ink. Some types of inks have thixotropy, so when the user uses the ink, it must be fully stirred. The viscosity of the ink affects the flow of the ink. The user must add an appropriate amount of diluent according to the instruction manual when using it. The diluent has the ability to dissolve. The drying speed must be suitable for the use of the type. Otherwise, the ink flowability will be affected, the lubricity is high, and the ink flow is generally good. Users should try their best to use oily inks.

5. Ink adhesion and printing

Screen printing inks have different models according to different printing substrates. Therefore, users must carefully select the ink type according to the properties of the substrate and the cost. For those who do not understand the performance of the substrate, it is best to conduct printing tests. The ink adhesion depends on its internal properties. Quality, but also will be affected by the printing environment, the printing process, in order to ensure the adhesion of ink, it is best to pre-print substrate. Crosslinked screen printing inks generally have the best adhesion and a wider range of applications.

6. Ink resistance and printing

Print products more or less will require the printing ink has a corresponding resistance, including weather resistance, chemical resistance, resistance to mechanical processing performance; weather resistance refers to the ink resistance to light in the outdoor, resistant to rain; good weather resistance, ink for outdoor advertising. Manufacturers should have weather resistance indicators. The chemical resistance includes the resistance of the ink film to acid, resistance to extension, resistance to solvents, etc. The resistance to mechanical properties requires that the ink film does not change in post-processing conditions. Cross-linked curing inks generally have good chemical resistance and mechanical processability, but the printing inks of the component inks deteriorate with time, so the user should carefully select according to various conditions.

Author: Ruan Bizheng Source: China Screen Printing Industry