Properties of mica pearlescent pigments

Due to the different types of substances deposited and coated on mica microchips and the content of deposited substances, the structure of mica pearlescent pigments is also different, resulting in changes in properties and differences in uses, which are mainly reflected in the following aspects .

Pearl effect:

The pearlescent effect means that the pearlescent pigment has a pearl-like soft luster. The pearl luster is the result of multiple reflections and transmissions of incident light by the titanium dioxide polycrystalline film coated on the mica flakes, that is, the phenomenon of light interference. For pearlescent pigments with small particle size, because the titanium dioxide polycrystalline film covering the surface of mica flakes is divided into many tiny layers like natural pearls, when the incident light hits its surface, it will show a luster like silk. This luster is called "pearl". This optical effect of mica titanium pearlescent pigment is called "pearl effect".

Metallic Glitter Effect:

The specular reflection of light on a smooth metal surface is called the "metallic flash effect". A series of metallic luster can be obtained by coating mica flakes with titanium or other metal and non-metal oxides, or by performing surface metallization on the prepared mica titanium pearlescent pigments. For example, mica titanium pearlescent pigments coated with titanium dioxide alone can show eye-catching silvery white metallic luster; silvery white pearlescent pigments are coated with carbon black or graphite, which can produce a deep lead metal effect; coated with silver oxide and bismuth oxide The mica titanium pearlescent pigment presents black and bright black metallic luster; titanium dioxide and graphite are mixed and coated with mica titanium pearlescent pigment to obtain dark gray pearlescent pigment; the yellow interference color pearlescent pigment colored with iron oxide has a strong golden luster.

Perspective color flicker effect:

Mica titanium pearlescent pigment is composed of a layer of transparent metal oxide deposited on the surface of transparent mica flakes, whose refractive index is much higher than that of the base material mica. When light refracts, refracts, partially absorbs, and partially penetrates multiple times at the interface of transparent layers with different refractive indices, light interference will inevitably occur between various parallel reflected lights, thus producing a pearl-like luster. and colors. When the pearlescent pigment is made into a coating film or plastic film and observed, the observer can see the strongest interference color when it is at the reflection angle of light; when it deviates from the reflection angle, it can only see pearl white or other colours. This phenomenon of seeing different interference colors with different viewing angles of the observer is called "perspective color flicker effect".

Color shift effect:

The coating film or plastic film made of interference color mica titanium pearlescent pigment can display two different colors at the same time. This change in color is known as the color shift effect or dichromatic effect. The reflected color of the paint can be seen from the front, and the transmitted color can be seen from the side, and the hue is always complementary to each other. For example, the color of a car painted with pearlescent automotive paint colored with interference color magic pearlescent pigments will change with the curvature of the car body. The color transfer effect is manifested as changing from yellow to purple, from blue to orange, from green to red, that is, from one color to its complementary color. This special optical phenomenon is called "color shift effect". It is precisely because of the optical properties of pearlescent pigments that colorists can design and create various wonderful and fantastic decorative effects according to different aesthetic requirements.

Additional color effects:

Mica titanium pearlescent pigments can be mixed with transparent inorganic and organic pigments, or directly use these pigments to color pearlescent pigments, and the resulting color effects are very attractive. If copper phthalocyanine blue and copper phthalocyanine green are used to color pearlescent pigments, the color will not be weakened, but will be enhanced. This is the unique "additional color effect" of pearlescent pigments, also known as "color enhancement effect". A serious disadvantage of conventional metal pigments such as flash aluminum powder is that once mixed with such pigments and dyed with resin, the brightness and saturation of the color will be greatly reduced, thus making the pigments dark and dull. This is a technical problem often encountered when ordinary metal pigments are used for coloring paints and plastics. However, pearlescent pigments are not the case. The color of the paint after color matching or the color of the coating film after construction becomes more vivid and bright. This optical characteristic is called "additional color effect" or "color enhancement effect".

Three-dimensional space effect:

Regardless of the type of pearlescent pigment, it is always transparent or translucent flakes. When light hits the surface of the flake, it always reflects most of the incident light, and transmits the remaining light to the next layer of pigment wafers, so the reflection and transmission of light are repeated, and this is repeated many times until it passes through the base material. , reaches the titanium dioxide polycrystalline film on the backlight surface of the pigment flake, and is completely absorbed and reflected.

This optical characteristic makes pearlescent pigments have a profound three-dimensional texture in transparent coating films or plastic films. Although the geometric thickness of the film is very thin, it always gives the visual impression of a thick film. This is an important optical characteristic that pearlescent pigments are different from ordinary pigments. This kind of three-dimensional space texture is called "three-dimensional space effect".

Background contrast effect:

Since mica pearlescent pigments are always transparent or translucent flakes, its hiding power is far inferior to that of conventional titanium dioxide. Therefore, the transparent coating film composed of pigment wafers can be covered on the surface of colored objects, so that the transparent or translucent pearlescent pigment top coat of the underlying color is revealed. This optical characteristic is called "background contrast effect, which is not found in ordinary pigments and metallic pigments".