Interview Questions and Answers of Dyeing - Part 2

Introduction:

1st part of “Interview Questions and Answers of Dyeing Part-1” is published. Now I am publishing 2nd part of viva questions and answers of dyeing. Because previous article don’t fill up complete information for dyeing.

Interview Questions and Answers of Dyeing

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.

Read Aslo -

Reactive Dye

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.