Function pearls pigments in ink printing

Flexible printing, offset, gravure and screen are the four most popular printing methods worldwide, each with its own characteristics.

The printing industry is one of the main application areas of pearlescent pigments There are many printed products with pearlescent inks, including packaging materials, publications, household decoration materials, clothing, and even ceramics and household appliances. Pearl printing can be used in offset printing, gravure, flexo and silk, but the ink should be adjusted according to specific process requirements and characteristics of pearlescent pigments, and the relevant process parameters should be coordinated to achieve satisfactory piracy. Effect.

Compared to traditional pigments, pearl pigments vary considerably in chemical composition and structure, as follows: t

(1) The material is relatively large: in the case of offset printing, normal pigment granularity is 0.02 to 8m, carbon black is 0.2 to 0.7 μm, and the amount of pearlescent pigments is used for printing than 5 tom to 25 Micron is much higher than the first one. Larger grain sizes have some difficulties in relation to printing transfers.

(2) Flaky structure: This structure is determined by the shape of a mica's heart and is also the basis for expressing the fictitious effect. But it is difficult to translate print. In ink preparation, it cannot be operated with a high speed force, with a large shear force or excessive roll, or the pearl pigment will be destroyed.

(III) Surface morphology: A microscopic surface of the pearles pigment is a plurality of keys, so that surface energy is sufficiently high.

In order to avoid the aforementioned features that would interfere with actual printing, Belle has summarized some practical and effective experience on the basis of years of research for printing ink and printing manufacturers:

1. Pre-wetting of pearlescent pigments: The pearl pigments should be wetted before the pearlescent pigments are mixed into the ink. The solvent used to wet it should be compatible with the ink system. Good wetting allows the pearl pigment to be evenly spread into the ink, which is the base for printing high quality pearls. The wet material also grows dry powder “disposal” phenomenon during dispersal.

2. Spreading pigment in ink: Pearl pigment has a good dispersion capacity In general, low-viscosity ink can be used in low-viscosity ink Try not to use a three-cylinder mixer, high-speed or ball / bead mill, etc. . The pigment is broken and lost its luster. It is recommended to mix the pigment in the final stage of ink production. Using a high speed scanner or mixer, the mixed time per batch should be kept constant and shorter.

3. Use a medium of good transparency ink: whether ink or binder color, transparency is an important factor affecting the pearl luster of the ink.

4. The distribution characteristics of the pigment determines the effect: the more the pearl pigment circulating in the printed coating, the better the uniform effect, the better the pearl effect; The best effect will be achieved on the environment.