Properties and applications of pearlescent pigments

Pearlescent pigment is a kind of optical effect pigment, because it can present a certain metallic luster, so it is also called non-metallic pigment with metallic luster. Pearlescent pigment has the shining effect of metallic pigment, but also can produce the soft color of natural pearl.

When irradiated by sunlight, it can produce multi-layer reflection, and the reflected light interacts with each other to present soft and eye-catching or colorful luster and color. Pearlescent pigment is the most important coloring agent of beauty cosmetics for face, lips, eyes and nails. The use of pearlescent pigments has expanded from classic color cosmetics to personal care products, including skin and hair care products, and provides a unique aesthetic effect.

They can be widely used in paint, plastic, rubber, ink, paper, textile, decoration, handicraft, leather, enamel, ceramics, packaging products, printing and decoration and construction materials and many other fields.

Pearlescent pigments are made of substances with higher refractive index, which act as interference filters in environmental media with low refractive index. These filters divide the incident light arriving at a suitable angle between the interfaces of materials with different refractive indices into reflected and transmitted light parts of complementary colors (other angles of incident light can also be absorbed and reflected). This effect is the same with the phenomena we observe in our daily life, such as soap bubbles, spilled oil and the color of pearls.

The pearlescent pigment is a layer system, consisting of backing and covering layer, the backing is usually natural white mica, silica or aluminum flake; the covering layer is titanium dioxide or iron oxide, or CI 77510 (pigment blue 27, ferrous ferricyanide), or carmine, etc. The substrate must be flake crystalline, pliable and with a smoother surface. The thickness and refractive index of the metal oxide determine the interference effect.

The excellent chemical resistance and high temperature resistance of pearlescent pigments provide the possibility of its wide application in coatings, inks, plastics and many other fields, and they provide a new color system and color quality for these products. The pearlescent pigment has low heavy metal content and meets the relevant safety technical standards, thus it can be used in food packaging and children’s toys. Both acid and alkali cannot attack pearlescent pigments under normal temperature. Pearlescent pigment can’t be burned, non-spontaneous combustion, non-conductive, and can withstand high temperature of 600~800℃. Pearlescent pigment can also be used in the reactive coating of radiation curing system (electron beam curing, light curing). The special surface chemical structure of pearlescent pigment makes it have excellent hydrophilicity, so it can be applied to water-based coatings, but the lipophilicity is poor, so when it is used in organic system, it will have the problem of poor dispersion, and surface treatment of pearlescent pigment is needed, so that it can also be well applied in organic system.

Application of pearlescent pigment.

1.Textiles
Combining pearlescent pigment with textile can make the fabric have excellent pearl luster and color. Adding pearlescent pigment to printing color paste and printing on textile after post-processing can make the fabric produce strong pearl-like luster from various angles and multiple levels under daylight or other light sources.

2.Coating
Paint is widely used, whether it is car top coat, car parts, building materials, household appliances, etc. will use paint to decorate the color and achieve a certain protective effect.

3.Ink
The use of pearl ink in high-grade packaging printing is becoming more and more widespread, such as cigarette packets, high-grade wine labels, anti-counterfeit printing and other fields.

4.Ceramics
The application of pearlescent pigment in ceramics can make ceramics have special optical properties.

5.Plastic
Mica titanium pearlescent pigment is suitable for almost all thermoplastic and thermosetting plastics, it will not make the plastic products fade or gray, and can produce bright metallic luster and pearlescent effect.

6.Cosmetic
The variety, performance and color of cosmetic products depend on the diversity of pigments used in them. Pearlescent pigment is widely used as pigment for cosmetics because of its strong covering power or high transparency, good color phase and wide color spectrum.

7.Other
Pearlescent pigments are also used more in other production and daily life. Such as imitation bronze appearance, application in artificial stone, etc.