In the production process of membrane switches, there are some kinds of raw materials. Ink is one of the most important things. We take care of these indicators while checking ink is good or not: viscosity, fineness, hue, and adhesion fastness.

When checking the viscosity, dilute it with a matching mixed solvent to a specific viscosity (such as 18 seconds/25°C), and calculate the amount of solvent added, so as to eliminate the "false viscosity" that may be caused by accidents (the ink looks like thick, but you can't add the solvent).

The solvent directly affects the ink printing, and it is tricky. The main indicators to distinguish the quality of solvents are purity and moisture content. The quantitative and qualitative detection of solvents is carried out through chromatography, but the instruments required are expensive, and the technical requirements are high. If it is just for printing, and there is no need to worry about the dry lamination process, it will be much simpler. Here are what you can do.

Watch the appearance of the solvent. It should at least be clear and transparent. If there is turbidity or floating matter, this batch of solvents should be used with caution.

Smell the solvent. After being exposed to commonly used solvents for a long time, we may have a general impression of the smell of a specific solvent. If the smell of solvents is weird, we can make sure that the purity is not good.

The principle of varying dissolution effects can roughly measure the water content in the solvent. Use a 100ml glass measuring cylinder to take more than half a cup of transparent toluene solvent. Take a small amount of the solvent such as esters or ketones to be measured, and pour it evenly into the toluene.

After the solvent has just been poured, when adding toluene, observe whether there is turbidity (milky white). If there is, the water content in the solvent seriously exceeds the standard. Experience shows that when the water content exceeds 0.5%, this phenomenon will be obvious. The moisture test of benzene solvents can be determined by extracting the solvent through a long glass tube and observing whether there is stratification.

Requirements for pigment in printing

As we all know, the colored things in printing inks are usually pigments. They are colored substances with extremely fine particles. They are generally insoluble in water and binder materials. They are mostly suspended in solvents. Pigments can color the surface of an object (substrate).

Pigments used for printing inks must have high tinting power, light resistance and chemical stability. They have fine particles and good dispersion ability in general ink binders. Adding them to the ink makes good liquidity.

Among those types of inks, some indicators of pigments that membrane switch printing is concerned about are:

a. Color samples printed with the purest saturation of pigments;

b. Color measurement data of pigments;

c. Application characteristics of pigments, concentration, tinting power, dispersion and hiding power of standard fluidity;

d. Color fastness of printed matter.