The use of pearl powder in printing

Pearlescent pigments are mica flakes coated with metal oxides that produce pearl luster pigments. The appearance of the pigments is transparent and flat, with a larger diameter, smoother surface and a higher index of refraction than other pigments. The product is in powder form, non-toxic, odorless, acid and alkali resistant, non-explosive, non-conductive, non-occluded, with high heat resistance (900°C) and high weather resistance: excellent gloss, average effective refraction The rate is 2.5, of which iron products are up to 3.0.

First, the main purpose:

With the development of pearlescent pigments, the application of pearlescent pigments has been increasingly recognized by people. It can be used in automobiles, bicycle coatings, decorative architectural coatings, pearlescent inks, pearlescent leather, pearlescent plastic products, pearlescent cosmetics, etc. It can also be used in papermaking, Printing and dyeing, printing, printing, handicrafts, rubber, ceramics and other industries.

Printing inks: Pearlescent pigments, like other pigments, are used in a wide variety of printing inks to add elegant pearl sheen to paper, cardboard, wallpaper, plastics, and textiles. Pearlescent pigments have a variety of different particles that can be appropriately selected according to the printing method. Pearlescent pigments can be used alone or in combination with other transparent pigments or dyes to produce a wide range of high-end packaging printing products to obtain a series of multi-colored products.

Second, the main product series:

(1) Silver white series: According to the type of titanium dioxide, the coating rate and the size of the particles are different, various types of silvery white pearl luster pigments can be obtained, large particles show glittering dazzling metallic luster, and small particles show silky softness Color, can also be used according to different needs of different titanium dioxide crystal form. If the weathering effect is required, a pearl luster pigment coated with mica titanium dioxide coated with mica may be selected.

(2) Rainbow Color Series: This series of pigments can exhibit different rainbow-like colors. This effect is caused by the interference color of light. As the thickness of the titanium dioxide coating changes, when light hits the surface of the pigment, part of the light is reflected (in this case, red light is assumed), and another part of the light (in this case, red light) penetrates and forms. Different reflected light and transmitted light.

(3) Coloring series: This series of pigments is a special pearlescent pigment that is composed of a layer of titanium dioxide covered with a layer of mica followed by a layer of other transparent pigments. It is not only pearl luster but also has those transparent pigments. The charming colors.

(4) Mica iron series: Mica iron series pearlescent pigments are directly coated with an iron oxide film on the surface of mica. According to the thickness of iron oxide coating, interference colors such as bronze, reddish brown, burgundy, purple, red and green are produced. Bright, strong gloss, color strength, although it is non-metallic itself, but it can produce metallic luster.

(5) Metal series: This series of pigments is covered with a layer of titanium dioxide on the surface of natural mica, and then covered with a layer of iron oxide, not only has a pearl luster, but also with the color of iron oxide.

Third, the application of printing ink

Pearlescent pigments, like other pigments, are used in a wide variety of printing inks to add elegant pearl sheen to paper, cardboard, wallpaper, plastics, and textiles. Pearlescent pigments have a variety of different particles that can be appropriately selected according to the printing method. Pearlescent can be used alone or in combination with other transparent pigments or dyes to give a series of multi-color effects. The proper amount of pearlescent pigment can be uniformly dispersed in the ink base as long as it is simply stirred.

1, the choice of pigment

Pearlescent pigments have the ability to have a large optical change effect, from bright and bright to soft and elegant, this special effect depends on the choice of pearl pigment and media. Each series of pearlescent pigments has different levels of brightness, different particle sizes and special color effects. However, the effect of pearlescent pigments will be influenced by the medium. The transparent medium can maximize the color of the pigment. When the pearlescent pigments are mixed with the poorly transparent medium, the pearlescent effect will be greatly affected.

When the pearlescent pigment is mixed with other colorants, a good transparency or dye should be selected.

2. Applications such as gravure printing inks:

The use of a small amount of solvent or ink to wet the pearlescent pigment first gives good dispersion.

3, printing

Printing can be divided into offset printing, flexographic printing, gravure printing, screen printing, and thermal relief printing. The application of pearlescent pigments in different printing methods is different.

The main factors influencing the pearlescent effect of printed materials are: the nature of the ink, the transfer method of the ink, the printing process, and the type of the substrate.

Pearlescent pigment particles are larger than traditional ink pigments, so some printing conditions must be adjusted to ensure print quality. The number of lines (bars) in the transfer and gravure rollers should be corrected to 75-100 lines (bars). The screen mesh at 100 mesh and 250 mesh is preferred to accommodate the use of larger particles, thus also making the ink film thicker. To adjust the drying temperature, and pay attention to the smoothness of the paper. The volatility of the solvent and the nature of the developer.

When the surface of the printed body is calendered or embossed, the effect of pearl luster will increase.

After printing by dark paper and embossing, it can produce a special effect gift wrapping paper. After the final bleached natural kraft paper is printed and then calendered, it can produce metallic luster.

5, the scope of application:

Packaging containers, wrapping paper, book covers, covers, calendars, desk calendars, tobacco and wine packaging, business cards, wallpaper, cardboard boxes, plastic cloth, plastic film, textiles and other products.

Due to the intense grinding and high shear stirring, the pigment will be broken and tarnished. Under normal circumstances, the pearlescent pigment is uniformly added to the printing ink in the final procedure. When using a dispersing machine and high-speed stirring, each batch of stirring time must be Keep it constant and shortest. Special attention must be paid to the use of transparent linking materials as much as possible to avoid the use of opaque and light scattering additives.

Fourth, common problems and solutions

A. If the pearl effect is not obvious

â—Ž Added strong hiding power or other fillers.

â—Ž Reassess whether the amount of pearlescent pigment is too much or too little.

â—Ž Check whether the screen line and the engraving depth of the printing roller match the particle size of the pearlescent pigment and adjust the screen printing mesh.

â—Ž Insufficient ink transparency or film formation, surface gloss is not enough, it is recommended to use better ink to improve.

â—Ž It should be checked whether the pearlescent pigments have been fully dispersed. The aggregation of pearlescent powders will affect the pearlescent effect and cause other problems.


B. Pinholes or small bubbles appear on the printed surface

â—Ž The ink contains water or poorly dispersed particles, or the surface of the print will fall into dust, which will produce the above defects.

â—Ž thinner does not match

C, large area of ​​the surface of the seal longitudinal stripes

â—ŽThe ink viscosity should be adjusted properly

â—ŽThe speed and pressure of the printing should be adjusted to get improved and screen tension and spacing.

â—Ž Check the scraper for damage and renew it if necessary.

五、Precautions when using pearlescent pigments

1, pearlescent pigments and transparent dyes or pigments used in conjunction, you can get a unique and beautiful color effect, but if used with opaque pigments, will reduce the pearl luster.

2. High-shear stirring mixing or long-time stirring and mixing, pearlescent pigment particles will be destroyed, which is the reason for the decrease in pearl luster.

3. When the ink or coating is at a low viscosity, the pearlescent pigment particles will precipitate. Please stir it when using.

4. Due to the phenomenon of complementary colors, please do not mix pearlescent rainbow colors.

5, in order to have a good uniform dispersion, please pearlescent pigment pre-wet, and then put into an aniseed material and solvent wetting, and then mixed with pearlescent pigments. (Yang Yaonan)