Color Index

APPLICATION OF COLOR INDEX

Color Index is the most authoritative way to search your exact requirement of Dyes and Pigments from the vast range of colors available today. It is basically a compendium of dyes. 

Generally a dye is referred to by a simple name that is comprehended by people who is working with them. Which we can say as a common name. But the problem is that it is not uncommon for a dye to have names that are more than one. For example take basic fuchsia which was earlier known as magenta. Another example: light green, has also been popularly used to refer to dye methyl green. Some of these names are historical or there can be cases where in order to sell a single compound different manufacturers gave different names, to avoid violating copyright or trademarks of each other.

WHAT IS COLOR INDEX

Color Index is basically a compendium of dyes, that has a huge volume of data. It was prepared in the UK by the Society of Dyers and Colorists. In the USA by the American Association of Textile Chemists and Colorists. It is available both in the book form, and on CD as well. In this reference book there is a very specific system to identify individual dyes. A five digit number is assigned to each individual chemical that is used as a dye. Consequently individual dyes get identified with reference to their CI number only. For example when specifying a dye for use in any staining method the CI number must be always provided.

The color index also has a system to assign a specific name (CI Name) for each of the dyes, to avoid any confusion regarding chemicals. The name given is totally based upon the dye's mode of behavior, base color and action. This is followed by a number. To give an example, the CI name given for chromoxane cyanine R (CI 43820) is Mordant Blue 3. Thus, the CI name therefore gives a specific way to identify a dye. Although the CI name is used less often than the CI number, the CI name is as useful in identifying a dye for a particular staining method.

The following table illustrates the use of the Color Index for yellow Organic pigment

C.I. Generic Name	C.I. Number	CAS Number	Color
P.Y.17	21105	4541-49-1	Greenish Yellow
P.Y.74	11741	6358-31-2	Bright greenish yellow
P.Y.81	21127	22094-93-5	Lemon yellow shade

FEATURES OF THE COLOR INDEX

• Detailed record of products that can be found in the market is put under a Color Index reference. For each product name there is a listing of the manufacturer's name, principal usages, physical form, and comments to help the customers. This format has been devised after taking into confidence the coloration industry (including prominent manufacturers, users, CPMA and ETAD).
• Colorants get listed in the Color Index strictly in accordance with the system of (a) Color Index Generic Names (b) Color Index Constitution Numbers.
• Around 27,000 individual products are listed under a total of 13,000 Color Index Generic Names.
• Chemical structures that are depicted is strictly in accordance with the results obtained by modern researches on molecular conformation.
• Popular format has been devised with an unique 'fingerprint' concept.
• Part 1 of the information gets freshly confirmed with suppliers and manufacturers. Part 2 of the information is either confirmed freshly with suppliers and manufacturers or is depicted as "carried over from the previous edition.

• Textile manufacturers.
• Paint manufacturers as well as suppliers.
• Colorant users, suppliers and manufacturers.
• Manufacturers and suppliers of Plastics.
• Testing labs, Libraries, academic institutions.
• Producers of Printing ink along with suppliers.

HIGHLIGHT OF THE COLOR INDEX
The following three tables highlights major information regarding the Color Index:

Part 1 Dye Groupings:  

• Acid
• Mordant
• Disperse
• Natural Dyes and pigments
• Reactive
• Vat

Part 2

• Manufacturing methods
• Structural formula (if known) of Dyes
• References (literature and patents)

Part 3

• Indexes
  • Abbreviations of manufacturers' names
  • Generic names
  • Commercial names

Manufacturing Of Man made fiber

Most synthetic and cellulosic manufactured fibers are created by “extrusion” — forcing a thick, viscous liquid (about the consistency of cold honey) through the tiny holes of a device called a spinneret to form continuous filaments of semi-solid polymer.
This types of fiber can be produce in three ways. They are:-

• Metlt Spinning
• Dry Spinning
• Wet Spinning

Melt Spinning
In melt spinning, the fiber-forming substance is melted for extrusion through the spinneret and then directly solidified by cooling. Nylon, olefin, polyester, saran and sulfar are produced in this manner.
Melt spun fibers can be extruded from the spinneret in different cross-sectional shapes (round, trilobal, pentagonal, octagonal, and others). Trilobal-shaped fibers reflect more light and give an attractive sparkle to textiles.
Pentagonal-shaped and hollow fibers, when used in carpet, show less soil and dirt. Octagonal-shaped fibers offer glitter-free effects. Hollow fibers trap air, creating insulation and provide loft characteristics equal to, or better than, down.

Dry Spinning
Dry spinning is also used for fiber-forming substances in solution. However, instead of precipitating the polymer by dilution or chemical reaction, solidification is achieved by evaporating the solvent in a stream of air or inert gas. The filaments do not come in contact with a precipitating liquid, eliminating the need for drying and easing solvent recovery. This process may be used for the production of acetate, triacetate, acrylic, modacrylic, PBI, spandex, and vinyon.

Wet Spinning
Wet spinning is the oldest process. It is used for fiber-forming substances that have been dissolved in a solvent. The spinnerets are submerged in a chemical bath and as the filaments emerge they precipitate from solution and solidify.
Because the solution is extruded directly into the precipitating liquid, this process for making fibers is called wet spinning. Acrylic, rayon, aramid, modacrylic and spandex can be produced by this process.

Microfiber

One of the most important developments in recent years has been the technology to extrude extremely fine filaments (less than 1.0 denier) while maintaining all of the strength, uniformity and processing characteristics expected by textile manufacturers and consumers. These “microfibers” are even finer than luxury natural fibers, such as silk . This comparison, coupled with their exceptional performance, has led some in the industry to refer to microfibers as “supernatural”. They live up to that name.

In many product lines, it is the luxurious feel and look of the fabrics which makes microfibers so special. In others, it is this unique physical and mechanical performance.

Consider, for example, the advantages of polyester microfiber when used in outerwear. A raincoat or jacket made from 100% microfiber will be much lighter and more comfortable than one made from conventional fibers. Since the small filaments pack closely together, they provide a wind barrier to prevent loss of body heat and assuring comfort on chilly days. This close packing of fibers, together with polyesters' natural resistance to wetting also gives the fabric the ability to repel rain. The non-wetting surface of the fibers causes water to form beads (like rain on a newly-waxed car). These beads are much larger than the spaces between the yarns and water is effectively locked out. And this is done without the need for chemical treatments or coatings which can make the fabric heavier and less able to "breathe". Fabrics from microfibers, on the other hand, breathe well.Although the spaces between the yarns are too small to be penetrated by liquid water, they are ample for the passage of moisture vapor, leaving the wearer dry and comfortable.

This is only one example. Microfiber yarns are now available for most major generic fibers. They can bring their outstanding performance to a wide variety of end uses.

Finishing Of Dyed Fabric

Finishing is important for dyed textile materials for ensuring the desired quality. The main objective of finishing are given below:-

Objective of finishing:

• Improving the appearance –Luster, whiteness etc of the fabric.
• Improving the fell which depends on the handle of the material & its softness.
• Wearing qualities, non-soiling, anti crease, anti shrink, etc
• Special properties required for particular uses, such as water-proofing, flame-proofing, etc
• Increase the weight of the cloth

Types of finishing:

1. Chemical finishing: Use of softeners and different types of finish chemicals.

2. Mechanical Finishing: Finishing by mechanical treatment. For example, compacting with compactor machine.

  

For open form of fabric following m/c are required:

Hydro-extractor >De watering  >Slitter  >Dryer >Stenter>Open compactor

For Tubular form of fabric following m/c are required:

Hydro-extractor>De watering>Dryer>Tubular Compactor