pigments and their characterstics

master seminar

1. Ba h ir Dar University First Year M.SC In Textile Chemistry Dyes and Auxiliaries Seminar on Pigments and Their Characteristics Prepared by: Asn ake Ketema 8/07/2010 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. Pigme n t D y e 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 & Inorganic Pigments 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

10. 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

11. 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

12. 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)

13. Classification of Pigments

14. 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

15. Red Pigments m odera t e ligh t -fast n ess, good chemical resistance structure of red pigment

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

17. 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.

18. 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

19. 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.

20. 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 .

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

22. 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

23. 6. Dio a xazine Pigments, violet 23 & 37

24. 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

25. 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

26. 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

27. 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).

28. 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 ,

29. 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 .

30. 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.

31. 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. L aux 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

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

33. 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

34. 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

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

36. 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

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

38. Thanks