Printing Inks Physical And Chemical Properties

Printing Inks physical and chemical properties mainly includes density, fineness, transparency, gloss, light resistance, heat resistance and alkali, acid, water, solvent(alchol) resistance


Printing Inks Density:

Density is defined as under 20 ℃, the weight per unit volume of ink. The unit is g/cm³. The density is decided by the raw material and percentage, and influenced by outside temperature. Ink density has certain relationship with printing process. The density will influence the ink consumption during the printing process. Under same condition, the bigger density is, the more ink it will be used.
Large density mainly caused by large density pigment in the ink. In the printing process, due to the Vehicle cannot transfer the high Density pigment, it lead to the accumulation of pigment and solid particles on the ink roller, PS plate, blanket, causing clogging. It will happen especially in high speed printing work or by low concentration. In addition, mixture of high density ink and low density ink, or the density difference is too big can cause ink stratification. The low density ink will floating, the high density ink will sink, in this way, the surface of ink will more close to color of low density ink, and bottom of the ink will close to the high density ink. Generally, Printing ink density is between 1g/cm³ and 2.25g/cm³.

Printing Inks Fineness

Fineness is the dispersion of pigment, stuffing and other solid compound in Vehicle. We also can call it dispersity. It indicates the size of solid particle and dispersity in the vehicle. The ink fineness is good means the solid particle fineness is good, and dispersity of solid particle is good. Fineness of the ink depends on the wet level of pigment from vehicle, ink mixing, and rolling grind.
The fineness of the ink will influence the ink rheology, fluidity and stability, printability, is a very important quality spec. The bad fineness and big size of solid particle will case clogging. in offset printing and gravure printing, it will destroy the plate and scraper. And due to non-uniform dispersion of the pigment, the intensity of the color of the ink can not be fully realized. It will influence the ink tinning strength, dry and gloss.

Printing Inks Transparency


Transparency means the level of ray refraction (transmission) produced by ink. Transparency in the printing is a uniform coating ink film makes background objects appear to the level of its original color.
When transparency of ink is low, the background is not fully apparent; it will cover the background to a certain extent, so this performance is also known as ink opacity.
Inversely proportional relationship between transparency and opacity inks
Transparency is measured by the thickness when ink completely convered the ground color ink. The thicker, the high transparency it is, and the low opacity it is.
Transparency depends on the ink pigments and binders refractive index difference, and be in line with pigment dispersity. The big refractive index difference between pigments and vehicle, the pigments will disperse better in vehicle, and the better ink transparency it will be.

printing inks