What are the commonly used pigments for powder coatings?

Pigments suitable for powder coatings can be roughly divided into four categories according to their properties and functions: coloring pigments, metallic pigments, functional pigments, and extender pigmen.

Coloring pigments are divided into two categories: organic and inorganic, covering almost all hue system coatings online at coating.

0 Precautions for choosing pigments

The formulation of high-quality powder coatings is inseparable from the selection of high-quality pigmen.

There are many types of pigments with different properties, and not all pigments can be used in powder coatin.

Pigment dispersibility is better, the optimal dispersion particle size is 2 ~ 9μm, and it is not easy to agglomera.

Most varieties of powder coatings are used for decorative purpos.

Because the baking curing temperature of powder coatings is high, the heat resistance of powder coatings is bett.

Pigments should have certain light and weather resistance, such as not easy to fade, resistant to chalking, and durable in physical properti.

In powder coatings, the pigments of pure white powder coatings are mainly titanium and matched with a small amount of colored pigmen.

0 Common pigments

1 Inorganic Pigments

1 Carbon black

Carbon black is the most important black pigme.

2 Iron oxide pigments

These pigments are mainly divided into three categories: iron yellow, iron red and iron black (including iron brow.

3 Chromium pigments

It mainly includes three categories: chrome yellow, molybdenum chrome red, and chrome gre.

4 Ultramarine

The chemical name of ultramarine blue is sodium aluminum sulfosilicate, rich in hue, from pink to purple, good heat resistance, non-migratory, non-toxic, and easy to disper.

2 Organic Pigments

1 Organic Yellow

Mainly single and disazo pigments, there are many varieties, such as permanent yellow, benzidine yellow, light fast yellow, disperse yellow, pigment yellow and so .

Organic yellow pigments have high oil absorption, and when the amount used in the powder is high, it is prone to problems such as poor dispersion and color bleedi.

2 Organic Red

Like organic yellow, there are many varieti.

3 Metallic Pigments

1 Aluminum powder

There are two types: floating and non-floati.

Floating aluminum powder has strong metallic feeling and high hiding pow.

Adding a small amount of aluminum powder to the powder coating can completely cover the coating surface;

The surface of the non-floating aluminum powder is treated with a special coating, which mainly reflects the metal flashing effe.

Observation with an electron microscope shows that the aluminum powder is in the form of flak.

In powder coatings, aluminum powder must be post-mixed with gentle agitati.

High-speed or strong stirring will destroy the flake structure of aluminum powder, especially floating aluminum powder, and make it lose its metallic effe.

Powder coatings containing aluminum powder are not suitable for outdoor coating, because the main component of aluminum powder is metal alumin.

Under the conditions, chemical and physical changes such as oxidation will soon occur, which is manifested as weakened metallic feeling, gray and dark coating film, gray spots and so .

2 Copper and gold powder

The main component is copper, and some zinc and tin are added according to different hue requiremen.

Copper-gold pink is colorful, including bronze, red gold, blue-red gold, pure golden light, lemon light and varieti.

The copper-gold powder of different hue and particle size is selected and mixed into the powder, and the effect from silky soft to coarse and bright can be obtain.

The tone of copper gold powder is soft, simple and elega.

The main components of copper-gold powder are active metals, which are easily oxidized when exposed to the air, and are not suitable for outdoor weather-resistant occasions; aluminum powder can withstand temperature up to 1000 ℃, while copper-gold powder is just the opposi.

It will be discolored and blackened for a long time at 180 .

Many manufacturers use silica-coated copper-gold powder to improve temperature resistan.

3 Pearlescent Pigments

Pearlescent pigment is a transparent highlight with a strictly controlled thickness on the surface of the transparent mica she.

Metal oxide films (TiO2, Fe2O3, Cr2O3) with refractive index reflect hue and luster by refraction and transmission of light, and reproduce the elegant luster and color of natural pearls, shells, insects and meta.

Pearlescent pigments mainly include three series: silver white, rainbow and go.

Mixed into the powder after application, can not be extruded, it will destroy the structure of the pigment and lose the pearl effe.

The addition amount of pearlescent pigment in the powder should not exceed 2%, otherwise it will be difficult to spray, and the pigment will easily accumulate in the muzzle and barrel, which will affect the spraying efficiency and quali.

4 Other metallic pigments

There are mainly stainless steel powder, nickel powder, e.

, and the use surface is narr.

4 Functional Pigments

1 Luminous Pigment

It is an alkaline earth metal aluminate rare earth energy storage luminescent material with excellent light resistan.

The amount added in the powder coating is large (>10%), and the post-mixing process is adopt.

Lighting time > 1

2 Conductive Pigments

The most commonly used is conductive carbon black, with an average particle size of 25nm and a specific surface area of ​​125-200㎡.

Light-colored conductive pigments have been developed in gray powder fo.

The use of luminous pigments when formulating powder coatings can reduce the surface resistance of the coating, make it antistatic, and prevent dust and accumulation of charges on the surface of the coati.

It is suitable for applications such as electronic product assembly tables and computer room floo.

It should be noted that gold, silver, copper and other metal powder pigments and antistatic agents (cationic quaternary ammonium salts, anionic alkyl esters) have similar antistatic effects, and most of them are added during extrusi.

Excessive addition will lead to powder resistan.

If it is too low, the chargeability during powder coating will be po.

3 High temperature pigments

Generally inorganic oxides, the main colors are yellow, blue, green, bla.

Temperature resistance>800℃, with excellent weather resistan.

4 Fluorescent Pigments

 For making fluorescent powder coatings, fluorescent pigments with good temperature resistance should be selected, and their dispersibility and tinting strength should be consider.

At present, the fluorescent pigments that can be used in powder coatings are mainly pink and gre.

5 Extender Pigments

1 Titanium Dioxide

It is the best white pigment and is often classified as an extender due to its high usa.

For powder coating, it can effectively scatter visible light to impart whiteness, brightness and opacity to the coating fi.

Chemically inert, insoluble and thermally stable under harsh conditio.

Commercial titanium dioxide usually has two crystalline forms, namely anatase and ruti.

R-type (rutile) titanium dioxide is the most used in powde.

It is not pure titanium dioxi.

Most of them are precipitated or mechanically blended with alumina or silica to adhere to the surface of titanium dioxide particles to improve performance, such as Hiding power, easy dispersibility, weatherability and fade resistan.