Sinopigments pearl pigment should be well oriented in the film by giving ,moderate FLOW and PRESSURE .
For optimum pearl luster effects, it is necessary to orientate pearl luster platelets parallel to the surface. In printing, good orientation of pearl pigment can be easily achieved.
The pulverulent pearl pigments should be incorporated by thorough but gentle mixing, since the thin pigment platelets are sensitive to fracture. It is advisable first to prepare a paste of the pearl pigment in a part of the liquid printing ink or in a solvent or diluent which is compatible with the printing ink,and then to stir the paste homogeneously into the rest of the printing ink which in other respects is completely formulated. Simple stirrers are suitable for this step.
Over-mixing, over-kneading or ever over-processing can lead to the fracture of the plate-like flake structure of pearl pigment into smaller light scattering particles, producing a less lustrous appearance in the film. Pearl pigments are destroyed, if it is dispersed like general inorganic pigments. In this case, pearl luster effect is weaker or is not generated. You should avoid overdispersing using a dispersing machine such as sand-mill.
When combining with pearl pigments, the colorants shoud be well dispersed. Poor dispersion of othe colorants sometimes cause pearl pigments to act as beads, which changes dispersion condition of other colorants (grow corpusle). This problem occurs expecially in the applications in paints and inks. Accordingly, you should be very careful of the dispersion of colorants. Insufficient dispersion of other colorants cause the particle size of other colorants to change due to pearl pigment.
Cleaning condition of processing machines is also very important to application. Insufficient cleansing of printing machine woul probably bring out foreign matter of the final product.
Pearl pigment can be used in combination with other colorants in order to hide background color. For a good pearl luster effect, it is a very important factor to combine and /or balance between pearl pigments and other colorants.
It is very important check background color especially in printing field. Because, in most cases, any other colorants are not
added to pearlized ink.
The achievable pearl luster effect can be increased still further the more smooth and even the surface of the printing stock selected. Therefore, on printing, for example, paper of high quality is always preferable.
Most print systems do not adopt (top) clear layer on pearl luster. The use of (top) clear layer changes the pearl luster effect of final product. |
