This document provides information about pigments, including: - Pigments are insoluble coloring substances that are used to color materials without chemically bonding to them. - Organic pigments include azo, polycyclic, and phthalocyanine pigments. Inorganic pigments include titanium dioxide, iron oxides, cadmium and chromium pigments. - Pigments are used to color fabrics, leather, paper, plastics, paints and other materials. They provide properties like color strength, light fastness and weather resistance.

1. Bahir Dar University
First Year M.SC In Textile Chemistry
Dyes and Auxiliaries
Seminar on Pigments and Their Characteristics
Prepared by: Asnake Ketema8/07/2010
Course Manager. D.r Abera K.
Ethiopia Institute of Textile and Fashion Technology (EiTEX)
1

2. Outlines
22/12/2017 2
Introduction
Classification of Pigments
Applications of Pigments
Summary

3. Pigments and Their Characteristics

4. Introduction
• Pigment is derived from word “pigmentum” means
coloring matter.
• Pigments are coloring substances, which do not enter into
chemical reactions with polymers.
• Pigments are organic and inorganic materials which
are practically insoluble in medium.

5. Pigment colorants tend to be
• highly durable
• highly heat stable
• solvent resistant
• Good Light fast
• hard to process
• have poor color brilliance
(A. Gürses et al 2016).

6. In selecting a pigment for any particular product.
 Refractive index
 Light fastness
 Bleeding Characteristics
 Particle size and shape

7. Pigment
Dye
Differences between Pigments and Dyes

8. Pigment
• No affinity/substantivity to fiber
• Insoluble in water or low solubility
• Need binder for fixation onto fiber
Dye
• Affinity to fiber
• Water soluble. Exception disperse dye
• have interactive forces between dye‐fiber

9. Difference between Dyes & InorganicPigments
DYES PIGMENTS
1. Water solubility is 70% 1. 100% water insoluble
2. Dyes have direct affinity to textile
material
2. They have no direct affinity to textile
materials
3. Auxochrome groups are present 3. Auxochrome groups are absent
4. Most of the dyes are organic 4. Most of dyes are inorganic
5. Costly 5. Cheap
6. No binding agent is required 6. Binding agent is required
7. Dye diffusions in the fabric 7. Pigment diffusions on the fabric

11. Properties of organic pigments
 High color strength
 Give bright shades
 High light fastness
 Good weather fastness
Properties of inorganic pigments
 Weak color strength
 Dull shades
 Low light fastness
 Low weather fastness

12. The Background history of pigments
Earth pigments are naturally occurring minerals containing metal oxides,
iron oxides and manganese oxides, that have been used since prehistoric
times as pigments. The primary types are ochre, sienna and umber.
Spain and France

13. Conti . . .
Pigments are used almost 30,000 years ago.
About 2000 BC natural ocher was burnt sometime in mixture
with manganese ore to produce red, violet and black
pigments for pottery.
The first synthetic pigment was Prussian blue which was
synthesized in 1704.(Ihsan Ali Wassan QUAID-E-AWAM UNIVERSITY)

14. Classification of Pigments

15. Organic Pigments
• Organic pigments are based on carbon chains and carbon
rings. However, they can also contain metallic (inorganic)
elements that help stabilize the properties of the organic
component
Examples
 Azo pigments
 Polycyclic pigments
 Anthraquinone pigments
 Triayl carbonium pigments

16. Red Pigments
 moderate light-fastness, good chemical
resistance
structure of red pigment

17. Yellow Pigments
They have low opacity and are soluble in aromatic
solvents

18. 1.AZO PIGMENTS
 Azo pigments are excellent coloring properties, mainly in the
yellow to red range, as well as good light fastness..
 The largest chemical class of compounds from which
pigments are made.
 The hues of the azo pigments range from red,yellow
and orange to blue.

19. 2. Isoindolinon pigment
 Derived from the tetrachloro-isoindolinone ring by
condensation with aromatic diamines.
 The shades range from yellow through orang to red.
 Highly application in industrial paints and automotive finishes and
plastics

20. 3. Poly-cyclic Pigments
 aromatic or heterocyclic ring systems
 They have good light, heat and weather fastness
 They are more expensive than azo pigments.
 They are use in all application paints, plastic, rubber, cement &
textile products.

21. 4.Phthalocyanine Pigments
They are produce by reacting metal salt with nitrogen source
compound & phthalic acid derivative
They show good solvent & migration resistance, light, heat,
chemical & weather fastness.

22. 5. Pigments
The colour covers from green, violet and blue

23. Conti . .
There are two types of these pigments:
1. salt of triphenylmethane sulfonic acid
2. salt of hetero-poly-acid with tungsten, silicon or iron
They have poor solvent resistance and limited light fastness but
have excellent colour brilliant other organic pigments.
Commercial application is for printing inks especially are for
packaging inks

24. 6.Dioaxazine Pigments, violet 23
& 37

25. Conti . .
 produced violet colouration
 combination with phthalocyanine blue pigment
produces a very reddish shade
 Dioaxazine Pigments are derived from triphenodioxazine, linear
system of five anelated rings
 They show extreemly light and weather fastness as well as
excellent solvent and migration resistance
 Commercial application include the pigmentation of
plastics, printing inks, spin dyeing and coating

26. Inorganic Pigments
• Inorganic pigments, chemical compounds not based on carbon,
are usually metallic salts precipitate from solutions.
Examples:
• White pigments
• Black pigments
• Special pigments
• Color pigments

27. Classification Of Inorganic Pigments
 White pigment : 1)Titanium dioxide
2)Zinc oxide 3)Antimony
oxide 4)White lead
5)Lead sulfate
 Colored Pigemts :1)Iron oxide
2)Red lead 3)Cadmium red
4)Lead silicochromate 5)Lead
chromates 6)Zinc chromates
7)Cadmium yellow 8)Calcium
plumbate 9)Chromium oxide
10) Prussian blue
11 )Ultramarine blue

28. White pigments
 All white pigments are inorganic compounds of titanium, zinc,
antimony, or lead. Presently, the most important white pigment
used in paints is titanium dioxide. Formerly, white lead and zinc
oxide were widely used.
 The range of available white pigment is wide and includes white
lead (basic lead carbonate, 2PbCO3.Pb(OH)2; lithopone (mixed
ZnS/BaSO4); zinc oxide (ZnO); antimony oxide (Sb2O3); and
titanium dioxide (TiO2).

29. Titanium Dioxide Pigment
Manufacture process of Titanium dioxide
 Titanium dioxide, also known as titanium(IV) oxide or titania, is the
naturally occurring oxide of titanium, chemical formula TiO 2. When used as a
pigment,

30. Ultramarine Pigments
 Attractive blue color, high light fastness, excellent resistant to
alkali and all organic solvents ,non toxicity, but pure resistant to
acids.
 The reaction takes 4-5 days in a sealed muffle furnace at 800 oc
sodium carbonate reacts with the alumina and silica to form a
zeolite, a hydrated silicate of calcium and aluminum. this reacts
with the sodium poly sulphides formed green ultramarine. At
the furnace cools, air diffuse into it and the primary green
oxidases to form raw blue ultramarine.

31. Iron Oxide Pigments
 The largest class of colored inorganic pigments
 Non- toxic and increasing important producing low price products
in a wide range of shades: yellow, orange, red, and black.

32. The manufacture of synthetic iron oxides
 solid-state:- this process involves the calcining of iron oxides,
sulfates, and chlorides in an oxidizing atmosphere to give reds,
browns and blacks
 precipitation and hydrolysis. Solutions of iron salts are mixed with
alkali and then exposed at temperatures above 90 0c causing
precipitation of the desired pigments this method is used to produce
yellow, oranges and reds.
 Laux process. This is a modification of the be champ process for the
iron reduction of nitrobenzene to aniline which leaves iron oxides the
residueincorporation of iron or aluminium chloride into the reduction
process produces high quality yellow and red iron oxide pigments

33. Cadmium Pigments
3
3
Better solvent fastness and high fastness to migration (plastics
and polyolefin).
The starting material cadmium sulphate (free from iron and
copper)

34. Chemical composition and classification of pigments
1. Mineral pigments: TiO2 white, carbon black
2. Metallic powder: Gold, bronze powder, silver powder
3. Pearled pigments: Pearl paste AC – 6
4. Organic compounds:
1. Azo pigment –yellow, deep blue, red, brown colors.
2. Pthalocyanine pigment – green, ultramarine
3. Vat pigments‐ gold, yellow, heliotrope
5. Fluorescence resin pigment (Luminous pigment) – lumogen

35. Organic Pigments vs Inorganic Pigments
Particular Inorganic
Pigment
Organic pigment
Color Dull Bright
Color strength Low High
Opacity Opaque Transparent
Light Fastness Good Vary from poor to
good
Chemical Fastness Poor Very Good
Solubility Insoluble in sovents Have little degree of
solubility
Degree of safety May be unsafe Usually safe

36. Applications of Pigments
• Fabrics
• Leather
• Building Materials
• Paper,
• Floor Covering
• Ceramic
• Plastic
• Cosmetics
• food, and other materials

37. Summary
• Dyes and pigments are coloring substances, substances
imparting a specific color to the substance (substrate)
being colored.
• Dyes, among which organic compounds predominate
but pigments are inorganic compounds.
• Dyes dissolve and react with the substrate being dyed.
• Pigments are insoluble and they color the substrate by
coating its surface

38. 1. www. Textile pigment slideshare.com
2. John shore, “colorants and auxiliaries” organic chemistry and application
properties second edition volume 1(2002).
3. J. R. ASPLAND, “Pigments as Textile Colorants Pigmenting or
Pigmentation”School of Textiles, Clemson University, Clemson, S. C.
4. Ihsan Ali Wassan, Dyes & Pigments. quaid-e-awam university of engineering,
science & technology, nawabshah, sindh, pakistan
References