Aniline-
Represented by the chemical
formula of C6H7N.
Is also known as aniline oil, Aniline is a very commonly used term in
the synthesis of dyes. In fact the term 'aniline dye' is used as a sort
of synonym for synthetic dyes.
Affinity
- It is referred to as the
attraction between two things. While in dyeing affinity it means the
preferential attraction of dye towards fibre rather than for solution
of the dye bath. A dye that has strong affinity easily leaves the dye
solution of dispersion. And attaches itself to the fibre being dyed.
Acid
Dye- A
large and popular class
of dyes which are applied to polyamide fibres from acidic solutions.
Essentially synthetic dyes, they are used for silk, wool and nylon.
Azo-
Azo refers to a chemical
compound that contains double nitrogen atoms with a double bond between
them (-N=N-). With more than 2000 organic compounds, azo dyes forms the
largest group of dyes. They display light-fastness, stability,
strongness and respond well to mixing.
"Azo" is the term applied for a class of dyes based on the above
chemical structure. Azo dyes may be found among the dye classes of
direct, acid, basic, reactive and disperse.
Basic
Dye- Basic dyes are the dyes
that is able to react with acidic groups on fibres. They are also
referred to as cationic dyes.
Bifunctional
Reactive Dye- These
are the
groups of reactive dyes that typically has more than one type of
reactive group in their molecule structure. They are special in the way
that these reactive dyes are designed for having the potential to react
with the fibre in more than a single way.
Binder-
Typically a material, that is
nearly colorless, used to attach a pigment to fabric binders are like
"glue" that holds the pigment in place. Examples are of Paints that has
pigments mixed with binders.
Cation-
It is a positively charged ion. Numerous chemicals applied in textile
processing are referred to as cationic. That means when the compound
ionizes in a solution, it's actually the positively charged ion that is
"operational".
Cellulose-
A polymer consisting of a large
numbers of units, each of the general formula represented by C6H10O5.
Chromophore-
It is a color-bearing compound, by their special property found in an
organic molecule they make it appear colored.
Colour
Index- A publication jointly
brought out by the Society of Dyers and Colorists of Great Britain and
the American Association of Textile Chemists and Colorists.
Chrome-
Any of some salts of chromium,
that is used in tanning and dyeing.
Direct
application- A method usually
used to describe a process where a solution of dye is locally applied
to different areas of fabric, like squirting, painting, spraying,
stamping, etc.
Direct
Dye- A class of dye based on
application method. Which is essentially carried out by immersing the
fibre in a dye solution without any requirement of other chemicals for
bonding the dye to the fibres.
Disperse
Dye- A dye that is seldom
soluble in water. Disperse dyes are found in the dye bath as a kind of
suspension or dispersion of microscopic particles, with only a
minuscule amount in true solution at any given moment of time.
Exhaust
Dyeing- Exhaust
Dyeing is used
for denoting the application of a dye bath of a moderately larger
liquor to goods ratio, where the fibre is immersed for a while. It
allows the dye molecules to exit the bath and get attach to the fibres.
Enzyme-
A type of protein that performs
the role of a catalyst in a biochemical reaction. Enzymes are now
popularly used in textile processing. Examples are Amylase enzymes are
applied for desizing, and cellulase enzymes are used in modification of
cellulosic fabrics.
Fixation-
Fixation refers to the formation
of a sort of final bond between the fibre and dye. The bond type formed
changes with the type of dye and the fibre. To cite an examples,
reactive dyes generally fixes by covalent bond, while in the case of
acid dyes fixing is done by a variety of mechanisms like hydrophobic
forces and ionic bonding.
Gel
Dyeing- A
continuous type of
tow-dyeing method where soluble dyes are used to wet-spun fibres in the
gel state (i.e. After the processes of extrusion and coagulation, but
before drying and drawing).
Illuminating
Dye- A
dye that is mixed with
discharge paste in printing methods also referred to as head dyes.
Indigo-
A sort of natural or synthetic
vat dye given the designation of Colour Index Vat Blue 1. Indigo is
perhaps one of the oldest colorants that is used for textiles.
Originally extraction was done from plants, but now it is usually
synthetic.
Liquor
ratio (also liquor to goods ratio)-
The ratio that is used to denote the weight of the dyebath or any other
processing bath to the weight of goods that is being dyed or processed.
Leveling
Acid Dye- A class of acid dyes,
leveling acid dyes offers bright colors and level very easily.
Lightfastness-
Light Fastness is typically used
as measure to ascertain how resistant a coloring material, such as dye
would
be fading when exposed to light.
There are a number of standard textile industry methods that evaluates
how lightfast a dyed fabric is.
Lake-
Lakes are the type of pigments
produced as a result of absorbtion of the dye on the substrate. Most
common substrate can be alumina hydrate.
Metal-Complex
Dye- A dye that typically has
co-ordinated metal atoms in its molecule. A very vital point here to
note is that unless the term "metal-complex dye" is applied in direct
association with a specific application class of dye, for example
"metal-complex reactive dye" or "metal-complex disperse dye" its use
can be deprecated.
Mordant-
Refers to chemicals that helps
in attachment of dyestuff to fibres by bonding to the fibre as well as
to the dye. A mordant must show high affinity for both dye and fibre,
performing its role to attach the dyestuff to the fibre.
Pigment-
A substance used in the
particulate form that is substantially insoluble in a medium. But
pigments can be mechanically dispersed in that medium to carry out
modification in its colour and/or properties of light-scattering.
pH-
A perfect measure of the
concentration of hydronium that is found in a solution.
Reactive
Dye- A
dye that, under proper
conditions, can react chemically with a substrate for forming a
covalent dye-substrate linkage.
Retayne-
A type of cationic dye fixing
agent. Typically used on cotton fabrics for improving wet fastness of
the direct dyes and to add color paper pulp.
Sulphur
Dye- A
dye, that contains
sulphur as an integral part of the chromophore and as well as in
attached polysulphide chains. Sulphur dyes are not soluble in water,
and must get converted to a soluble form before application.
Sublimation-
The conversion of solid directly
into gas, without passing through the liquid phase. Some disperse dyes
can sublime.
Sodium
Hydroxide- Represented by the
chemical formula of NaOH; it is a strong base; also called caustic soda
or lye, or just "caustic" in dyeing terms.
Tannic
Acid- A mixture of compounds
derived from natural sources like oak. Tannic acid treatment, followed
by a treatment of tartar emetic, has been reported to improve the
washfastness of dyed nylon or wool.
Union
Dye- A dye that is generally a
mixture of two or more different classes of dye, used to dye blends of
fibres.
Ultraviole-
Light that is beyond the portion
that is visible of the light spectrum at the blue end. It is the
Ultraviolet light that causes fading of colors, and makes fluorescent
compounds glow.
Vinyl
Sulphone- A type of reactive
dye, that is typically used for cellulosic fibres but with some use for
wool also. Vinyl sulphone reactive dyes are generally intermediate in
their reactivity, so they are used above room temperature, but
considerably below the boiling point of water.
Vat
Dye- Vat dyes are
water-insoluble dye, that usually contains keto groups, which is
normally applied to the fibre from an aqueous alkaline solution of the
reduced enol (leuco) form, that subsequently gets oxidised in the fibre
to an insoluble form.
Washfastness-
Washfastness is used to measure
resistance of a dye to washing out.
Wetting
Agent- A type of chemical which
helps the water to penetrate a material or to form a film over its
surface; usually it is a surfactant. Wetting agents are generally used
in the dyeing process where it helps the dye solution to penetrate to
the individual fibres.