Viva Questions and Answers for Dyeing Job

101. Give the chemical classification of disperse dye .
Ans: 1. Azo dyes, 2. Anthraquine dyes.
102. What are the methods of application of disperse dye?
Ans:
Method N (Normal temperature dyeing 80-100º C),
Method NC (Normal temperature dyeing 80-100º C or
Carrier method),
Method HT (High temperature dyeing 105-140º C),
Method T (Thermosol method 180-200º C),
Method Pad batch (Semi continuous method),
Pad steam method (Continuous method).

103. Which dispersing agents are used in disperse dyeing?
Ans: Soap, T.R.O oil, Formaldehyde etc.
104. Give some trade name of dispersing agent?
Ans: Setamol (BASF), Edamol (Sandoz), Hispogal (Hoescht).
105. What is carrier?
Ans: Carriers are dyeing assistants which alter the
dispersing properties of the dyes and physical
characteristics of the fibre.
106. Why sulpher dyes are so called?
Ans: They contain sulpher linkage their molecular structure.
They insoluble in water but dissolved in a solution of Na2S
which act as reducing agent.
107. What are the methods of application of sulpher dyes?
Ans: Fabric preparation > Preparation of sulpher dye >
Dyeing > Oxidation > after treatment > Dyed goods.
108. What are the defects of sulpher dye?
Ans: 1. Bronziness, 2. Tendering.
109. How azoic dyes are produced?
Ans: By reaction of two components Diaz component (Salt/
Base) and Coupling component (Napthol).
110. What are the different names of azoic dye?
Ans: 1. Ice color, 2. Magic color, 3. Napthol color, 4.
Pigment color.
111. Which group present in azoic dye?
Ans: Azo group.
112. With which azoic components rate of exhaustion
decrease?
Ans: Temperature.
113. Why azoic dye is called developed dye?
Ans: Due to formation of dye in fibre during dyeing process.
114. How many stages in azoic dyeing process?
Ans: 3. a) Naptholation, b) Diazotization, c) Coupling.
115. How insoluble napthol converted into soluble in water?
Ans: By treating with alkali.
116. How many types of napthol according to substantivity?
Ans: 1. Low substantively, 2. Medium substantively, 3.
Higher substantively
117. What is textile printing?
Ans: Textile printing is the process of applying colour to
fabric in definite patterns or designs. In properly printed
fabrics the colour is bonded with the fiber, so as to resist
washing and friction.
118. What area the printing ingredients?
Ans:
Dyes/pigment,
Wetting agent,
Thickener,
Solvents/dispersing agent,
Defoaming agent,
Oxidizing and reducing agent,
Catalyst and oxygen carrier,
Acids and alkalis,
Carrier and swelling agent,
Miscellaneous agents.
119. Why normal thickeners are not suitable for printing
with reactive dyes?
Ans: They contain terminal –OH group which readily reacts
with reactive dye.
120. What is finishing?
Ans: Before marketing, all the process which are applied on
fabric is called finishing.
121. Give the classification of finishing?
Ans: 1. Physical (Temporary, Permanent), 2. Chemical
(Temporary, Permanent).
122. What is mercerization?
Ans: It is physio chemical process when cotton /yarn is
treated with 15-25% (55-65%º Tw) caustic soda solution at
a temperature of 20-30º C
123. Why mercerization is used?
Ans: To increase the luster of fabric.
124. How rain water collected for dyeing?
Ans: Rain collected immediately after precitation, which is
the purest of all natural waters.
125. For which material permanent hardness in water
occurred?
Ans: Chlorides or Sulphates of Calcium and Magnesium.
126. Which oils are used in soap manufacturing?
Ans: Cotton seed oil, Coconut oil, Oliver oil, Soya bin oil,
Palm oils, Ground nut oil.
127. What is acid soap?
Ans: Soap and free fatty acid molecules can become
associated to form acid soap.
128. What is chromogen?
Ans: The dye structure which contain both chromophore
and auxochrome is called chromogen.
129. What is the mean of H.E.C?
Ans: Hydroxy Ethyl Cellulose.
130. How many types of dyeing machine is use?
Ans: 1. Fibre dyeing machine, 2. Yarn dyeing machine, 3.
Fabric dyeing machine.
131. What is shear stress?
Ans: Shear stress is the resistance of the liquid to flow
under the influence of an applied force
132. Why steaming is required?
Ans: Steaming is required after dyeing reactive dye fixation.
133. What is the reactive group of reactive dye?
Ans: Vinyl sulhone group & halogen group.
134. Why sodium chloride is used in dyeing process?
Ans: Sodium chloride is used as a electrolyte for penetration
of dye from dye bath to fabric.
135. Why wetting agent is used in dyeing process?
Ans: To remove surface tension.
136. Why sequestering agent is used?
Ans: To remove hardness of water.
137. What is problem produce for hardness?
Ans: Soap waste, scale form.
138. What is problem of scale?
Ans: Heal loss is produce.so cost is increase.
139. What is printing?
Ans: Printing is a localized dyeing.
140. Where binder is used?
Ans: In pigment printing.
141. Why binder is used in pigment printing?
Ans: For consist the dye in the surface of fabric.
142. What is the difference between dye & pigment?
Ans: Dye is soluble & pigment is insoluble.
143. What is styles of printing?
Ans: 1.Direct printing, 2.Discharge printing, 3.Resist printing
144. At WTP which part of hardness is removed?
Ans: Positive part (Ca+)
145. At WTP which part of hardness is not removed?
Ans: Negative part (CO3-)
146. Which part gives greater hardness?
Ans: Negative part.
147. What is half emulsion?
Ans: Emulsion thickeners are often mixed with carbohydrate
paste to give so called half emulsion.
148. What is oil in water?
Ans: Emulsion of oil in water. This emulsion consists of
small droplets of oil dispersed in water. The negative charge
of the anionic emulsion molecules absorbed on the surface
of the droplets prevents their coalescence. In textile printing
a typical emulsion thickener has about 70% white sprite in
water.
149. What are synthetic thickeners?
Ans: Solution of synthetic polymers. Slightly cross-linked
co-polymer of acrylic acid derivatives and acrylic ester
disperse in water but remain insoluble.
150. What are the advantages of synthetic thickeners?
Ans: On addition of alkali such as ammonia, the carboxylic
acid group dissociates forming the carboxylate because of
the repulsion of the negative charges. A colloidal solution
result with a substantial increase in viscosity. The polymer
does not dissolve because of the crosslinks between the
polymer chain.
151. .What is rotary screen?
Ans: In rotary screen printing coloured paste forced through
the open areas of a cylindrical printing screen that rotates
as the fabric moves beneath it .
152. What is the squeeze systems used in rotary screen
printing machine?
Ans:
Rubber Squeeze.
Double Squeeze.
Magnetic rod Squeeze.
153. What are the advantages of rotary screen printing
machine?
Ans:
High productivity.
Quality of end result.
Evenness of color.
154. What is the squeeze systems used in Flat screen
printing machine?
Ans: Parallel rubber blades.
155. What is adhesive system used in a fully automatic flat
screen machine?
Ans: This is more problem of a fully automatic flat screen
printing where colors are printed one after the other with
little time for dyeing of the deposited paste. For this reason
printing of large areas of colour is asually done last.
156. What is the fundamental mechanism of screen
printing?
Ans: Hydrodynamic pressure is built up in the print paste
between the squeegee and screen surface through which
paste is passed.
157. What is substantivity?
Ans: The attraction between a substrate and a dye
molecule.
158. What is affinity?
Ans: The quantitative expression of substantivity.It is
difference between the chemical potential of the dye in its
standard state in the fibre and corresponding potential in the
dye bath.
159. What is chromophore group?
Ans: The name is derived from the Greek Chroma=color and
phore from pherein=to bear. Chromophore are unsaturated
organic radicals. A molecules possessing no Chromophore
would be colorless.
160. What is auxochrome?
Ans: The name is derived from the Greek auxein=to
increase, and Chroma=color. Auxochromes intensify the hue
of the dye molecules color.
161. What is emulsion thickener?
Ans: Emulsion thickeners are helpful since mineral spirits
are excellent wetting agents for hydrophobic fibre.these
thickener increase levelness and penetration of the dye in
the fibre.
162. What types of dyes are used for silk dyeing ?
Ans: For brighter shade = Direct, Acid, Basic,& Vat dyes are
used.
To dye this fibre also, Mordant or chrome dyes and
premetalised dyes are used.
163. What is the end use of silk ?
Ans: End uses: Used in highly demanded cloths, Furnishing
in different curtains and In the sharee.
164.What is the effect of acids and alkali on silk?
Ans:
Effects of Acids:
Strong acid : Decompose
Moderate conc; acids : Causes construction.
Dilute acids: Not attack.
Effects of alkali:
Conc; caustic alkali: Silk dissolved.
Weak alkali as soap : Borase.
Ammonia causes : Little appreciable damage.
165. Mention the average length and strength of silk
filament?
Ans:
Average length = 300 m
Strength: Tenacity –Dry: – 4.3 g/d
Wet:-dry*0.92.
166. Mention the major silk producing country?
Ans: Producing country: People’s Republic of china, Japan,
Korea, Soviet Union, India, Italy, France, & the Hungary.
167. Mention the natural filament?
Ans: Silk, Mohair, Cashmere, Camels, hair, Alpaca, Angora,
Lama, Vicuna, & Gunaco Etc.
168. What are the end use of wool fibre?
Ans; Luxury coating, Sweaters, Shawls, Suit and dress
fabric.
169. What type of dyes are used for wool dyeing?
Ans; Easy to dye, Acid, Mordant or chrome, prematalized,
reactive, dye stuff is Suitable.
170. Briefly discuss the anionic polymerization process
with example?
Ans: Anionic polymerization process are given below;
171. Differentiate between Homo-polymer and Co-polymer?
Ans:
Homo-polymer: Homo polymer is polymerized from the or
only. One kind of monomer .example; Nylon 6, Nylon 11.
Co-polymer: Co-polymer is polymerized from two or more
different. Monomer .example; Nylon 6.6, Polyester.
172. What is Kinetic chain length?
Ans: The kinetic chain length can be defined as the average
number of monomer molecules consumed by each effective
free-radical generated by the initiator. It thus expresses the
number of monomer molecules added to a growing chain
from its initiation up to termination.
173. A polymer can suffer degradation mainly at two stages
of its life?-
Ans: A polymer can suffer degradation mainly at two stages
of its life. First during the fabrication process and secondly,
during its daily usages.
174. Classify polymerization?
Ans: Chain polymerization, Free-radical polymerization,
Ionic polymerization, Coordination polymerization, Step
polymerization, miscellaneous polymerization.
175. Define chain transfer again?
Ans: The termination of a growing polymer chain can take
place also. Through chain transfer reaction could be
represented as:
M+RH → MH+R
Where Ktr is the chain transfer rateconstant and RH the
chain transfer Agent.
176. By which pigments physically and chemically
unaffected?
Ans: The vehicle or substrate in which they are
incorporated.