There are many types and categories of colorants used for coloring plastics during the fabrication process. Historically speaking, colorants are categorized into three major groups which are; soluble dye, inorganic and organic pigment.

1. An overview of various types of colorants
for plastics
One of the main factors that are taken into account by the manufactures that deal in the
production of plastic products is the coloring agent. Epoxy is the most extensively used colorant
all over the world for inducing colors into plastic.
There are many types and categories of colorants used for coloring plastics during the fabrication
process. Historically speaking, colorants are categorized into three major groups which are;
soluble dye, inorganic and organic pigment. These three groups are quite distinct from one
another. The pigment group contains particulate material which remains unchanged during the
production of plastic. But the soluble dye goes into solutions and into the plastic at molecular
level. It has no different particulate identity. Now let us take a look at each of the three in detail:
Organic pigment: This pigment is made from hydrogen, carbon, oxygen, sulfur and nitrogen with
its bonded atoms. Sulfur, bromine, calcium, barium, strontium, manganese, chlorine, fluorine, can
also be a part of an organic pigment. The nature of this molecule is crystalline, and it absorbs light
to radiate color.
Inorganic pigments: These pigments are made from the combination of metallic elements or
metalloid which is combined with sulfur, oxygen, and orselenium. These molecules absorb the
light selectively to give out color. It must be retain in its particular form, so as to perform its
functionality of a plastic colorant.
Dyestuff or soluble dye:
This dye when dissolved in plastic loses all forms of crystalline characteristics. It operates on a
molecular level. These dyes get completely dissolved in the system. That is why it does not have
any particulate characteristic. It gives out color only through selective absorption. Which pigments
can range from being transparent or translucent to slight hazy or completely opaque, soluble dyes
only gives complete transparency.
Colorant forms:
The form, in which dyes and pigments leave from their manufacturing units, is in the form of
powder. They are put through a special process to boost the quality of the colorant, before it could
reach the company for the purpose of fabrication of the consumer products.
Raw color or dry color pigments:
These colorants are added to the powdered polymers. This is due to the fact that their size is quite
close to each other. Dry ones are added to the system as a single colorant or/and a blend of
various which are fabricated to suit the targeted color.
This consideration is signification because the addition of powdered colorants to cubes, pellets or
large polymer granules can cause separation during the process. This may result into non-uniform
or streak of colors. An important aspect is to boost the efficiency of the product.
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