Basic Viva For Textile Engineers (Dyeing Related) Part-5

 

121. Differentiate between Homo-polymer and Co-polymer?

Ans:

Homo-polymer: Homopolymer is polymerized from the or

only. One kind of monomer .example; Nylon 6, Nylon 11.

Copolymer: Co-polymer is polymerized from two or more

different. Monomer .example; Nylon 6.6, Polyester.

122. 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.

123. 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.

124. Classify polymerization?

Ans: Chain polymerization, Free-radical polymerization,

Ionic polymerization, Coordination polymerization, Step

polymerization, miscellaneous polymerization.

125. 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.

126. By which pigments physically and chemically unaffected?

Ans: The vehicle or substrate in which they are

incorporated.

127. List different types of washing faults?

Color shade variation

 Crease marks

 After wash hole

 Very dark and very light

 Bleach spot

 Bottom hem and course edge destroy

 Running shade

 Over blasting/low blasting

 Over grinding/low grinding

 Bad smell due to poor neutralization

 Poor hand feel

 To high hairiness

 Poor brightness

 High or low effect/abrasion on garments

 Spot on garments

 Out of range/ level of ph value of garments

128. List the chemical names which are used in washing Plant?

(i) Sodium mete bi sulphite

(ii) per oxide

(iii) Caustic soda

(iv) Soda ash

(v) LV (pocket clear)

(vi) Bleach Kci

(vii) Caustic potash

(viii) Phosphoric acid

(ix) Pumice stone

(x) Optical Brightening agent (3 types: Red, blue, yellow )

(xi) Sodium hypo sulphite

(xii) Sodium bi carbonate

(xiii) Enzyme (Acid, Neutral , SL enzyme)

(xiv) Acetic acid

(xv) Softener

(xvi) Desizing agent

(xvii) Potassium per maganate

(xviii) Micro emulsion silicon

(xix) Buffer, stabilizer, fixing agent, catanizer , resin, anti staining agent

(xx) Dye for tinting or over dyeing

129. Can I dye my cotton/silk/linen dress?

Possibly, but keep in mind: 1, the thread and zipper will remain the original color; 2. the trim issue (see above); 3. the stress of the warm-water-and-agitation process.

130. Explain different types of wet processing?

Normal wash / Garments wash/ Rinse wash, Pigment wash, Caustic wash, Silicon wash, Stone wash, Enzyme wash, Stone Enzyme wash, Acid wash, Bleach wash.

131. What action of Enzyme is on Garments?

The action of enzyme during enzyme wash, it hydrolysis the cellulose. At first it attacks the having projecting fiber and hydrolyzed them. Then it attacks the yarn portion inside fabric and partly hydrolyzed the yarn portion and faded affect is produced.

132. Explain softening process of silicon Wash?

Lot weight (approx 145 pies) ............ 70 kg

Add water @ L : R = 1 : 8 .............. 560 Liters

Add Acetic Acid @ 0.6 gm / liter ............ 336gm

Cationic Softener @ 1 gm / liter.............. 560 gm

Silicon (ME) @ 0.5 gm / liter ................ 280 gm

Temperature.......................... 40°c

Time................................ 15 to 20 minutes

Drain the bath

Then unload the garments on trolley.

133. Why Acetic Acid is used in Enzyme bath?

Acetic acid is used in enzyme bath to control the pH of wash bath and for proper action of enzyme. (To controlling the pH of enzyme because enzyme works at acidic pH).

134. Explain Desizing process of silicon Wash?

Desizing process of silicon Wash:

Lot weight (approx 145 pies) ............ 70 kg

Add water @ L: R = 1: 10.............. 700 Liter

Machine running

Add Desizing agent @ 0.6 gm / liter ............ 420 gm

Add Detergent @ 0.5 gm / liter.................... 350 gm

Temperature.......................... 50°c

Time...............................10-20 minutes

Drop the liquor

Rinse one time 3 minutes

135. Explain function of Hydro extractor machine?

Function of Hydro extractor machine is to squeeze the garments for removing the excess water from the garments.

136. Described machine names which are used in washing plant?

1) Washing machine ( No of M/c -10)

2) Dryer machine (No of M/c -10): gas dryer-09 and Steam dryer-01

3) Sample Machine (No of M/c-02)

4) Hydro (No of M/c -03)

5) Spray gun (No of M/c -02)

137. Explain different types of dry processing?

Sand blasting, Hand scraping, whiskering, overall wrinkle, permanent wrinkle, broken and tagging, grinding and destroy, pp spray and pp sponging.

138. What are the purpose of washing?

The first purpose is to remove dirt, dust, impurities of garments thus achieve wash look appearance and softness.

The other purpose is to bring faded look, old look, tinted or over dyed affect.

To increase color fastness, wash fastness properties no possibility of further shrinkage of wash garments.

139. Cannot polyester garments be dyed by mere mortals?

Polyester is created in highly controlled factory settings, using toxic chemicals at high temperatures. In addition, the dye is added when the fabric is in a liquid state. Using Rit or reactive dyes would be like trying to dye a plastic bag. The dye just doesn't stick. Similarly, acetate cannot be dyed.

140. What if you have a garment or fabric that is half or less polyester and the other portion a natural fiber (like cotton), you can try using the reactive dyes?

Keep in mind that the dye will take at about half strength. In other words, it's very hard to get a dark color saturation. Cotton mixed with a minimal amount of spandex (5-10%) will take the dye pretty well!

141. Explain Solid color dyeing cotton, linen, rayon, and silk?

The best dye for vivid, color- and light-fast color are the reactive dyes, Some crafts stores carry reactive dyes, also. Get catalogs and instructions from these sources and study the materials carefully.

142. Explain Silk dyeing?

Acid dyes as best for solid-color dyeing of silk. I personally use the reactive dyes on silk because they are so simple and can be done in the washing machine. However, on silk, the reactive dyes do not come out the same colors as on cotton, so it requires experimentation to get what you want. If you want true-to-swatch silk colors and want to experiment with the acid dyes, they require very hot water, either in the washer, or on top of the stove. Acid dyes will also dye nylon.

143. Explain Wool dyeing?

Acid dyes are also used for dyeing wool - again, they require very hot water, so your fabric must be able to withstand any resulting shrinkage, matting, or felting. For this reason, I do not recommend dyeing already-constructed wool garments, such as coats, sweaters, or dresses, unless they are really large, and/or you are completely willing to experiment with the results.

144. How to dye fabric in order to make quilts, garments, table linens, etc?

The best place to start is with the prepared-for-dyeing fabrics at Dharma Trading Co. Their fabrics have no coatings or treatments that would make them resist the dye. Cotton and linen fabrics from Dharma do not need to be washed before dyeing. They recommend washing silk fabrics with Synthropol first (also available from Dharma), in order to take out any remaining silk worm gum.

145. Can I dye my wedding dress/bridesmaid dress/formal dress?

The simple answer is no. The vast majority of these dresses are polyester and acetate. Even if they are silk, the construction will probably not hold up to the warm water and agitation process. In addition, any trim may not dye or could take the dye in a different strength or color.

146. Can I dye my blue baby blanket pink?

No, because you are combining colors, just as if you were painting pink over a blue water color painting. However, you can dye a white or natural color baby blanket pink.

147. Is there a white dye?

Technically speaking, no. Some fabrics and colors can be changed or lightened using a good dose of chlorine bleach. Caveat: Start with a cup of chlorine bleach. Keep in mind that bleach will deteriorate fabric and if you use too much, you may end up with a shredding rag. Dharma also sells a color discharger for removing dye from fabric. If you are willing to be unattached to the outcome, you can try these methods.

148. With all these caveats, what can I dye?

Prepared-for-dyeing garments, including everything available at Dharma Trading Co.; all-cotton sheets and pillowcases; all-cotton towels; vintage linens (many of these are sewn with cotton thread, which will dye); natural-fiber items that have faded and you want to restore them to their original color; cotton and rayon trims and laces; cotton undies (elastic will not dye); natural fiber yard goods.

149. Can I dye my upholstered chair/sofa/ottoman?

No. Don't even think about it, unless your piece is white or off white, and you are willing to undertake an experiment using SimplySpray spray-on fabric dyes.

Basic Viva For Textile Engineers (Dyeing Related) Part-3

 

61. Which group present in azoic dye?

Ans: Azo group.

62. With which azoic components rate of exhaustion decrease?

Ans: Temperature.

63. Why azoic dye is called developed dye?

Ans: Due to formation of dye in fibre during dyeing process.

64. How many stages in azoic dyeing process?

Ans: 3. a) Naptholation, b) Diazotization, c) Coupling.

65. How insoluble napthol converted into soluble in water?

Ans: By treating with alkali.

66. How many types of napthol according to substantivity?

Ans: 1. Low substantively, 2. Medium substantively, 3.

Higher substantively

67. 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.

68. 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.

69. Why normal thickeners are not suitable for printing with reactive dyes?

Ans: They contain terminal –OH group which readily reacts

with reactive dye.

70. What is finishing?

Ans: Before marketing, all the process which are applied on

fabric is called finishing.

71. Give the classification of finishing?

Ans: 1. Physical (Temporary, Permanent), 2. Chemical

(Temporary, Permanent).

72. 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

73. Why mercerization is used?

Ans: To increase the luster of fabric.

74. How rain water collected for dyeing?

Ans: Rain collected immediately after precitation, which is

the purest of all natural waters.

75. For which material permanent hardness in water occurred?

Ans: Chlorides or Sulphates of Calcium and Magnesium.

76. Which oils are used in soap manufacturing?

Ans: Cotton seed oil, Coconut oil, Oliver oil, Soya bin oil,

Palm oils, Ground nut oil.

77. What is acid soap?

Ans: Soap and free fatty acid molecules can become

associated to form acid soap.

78. What is chromogen?

Ans: The dye structure which contain both chromophore

and auxochrome is called chromogen.

79. What is the mean of H.E.C?

Ans: Hydroxy Ethyl Cellulose.

80. How many types of dyeing machine is use?

Ans: 1. Fibre dyeing machine, 2. Yarn dyeing machine, 3.

Fabric dyeing machine.

81. What is shear stress?

Ans: Shear stress is the resistance of the liquid to flow

under the influence of an applied force

82. Why steaming is required?

Ans: Steaming is required after dyeing reactive dye fixation.

83. What is the reactive group of reactive dye?

Ans: Vinyl sulhone group & halogen group.

84. 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.

85. Why wetting agent is used in dyeing process?

Ans: To remove surface tension.

86. Why sequestering agent is used?

Ans: To remove hardness of water.

87. What is problem produce for hardness?

Ans: Soap waste, scale form.

88. What is problem of scale?

Ans: Heal loss is produce.so cost is increase.

89. What is printing?

Ans: Printing is a localized dyeing.

90. Where binder is used?

Ans: In pigment printing.

Basic Viva For Textile Engineers (Dyeing Related) Part-2

 

31. What is consumer textile?

Textile not falling into the categories of apparel, furnishing, household and industrial, tents and back packs may be referred to as consumer textile.

32. What is fashion color?

Color within a color range perceived as being fashionable.

33. What is flocking?

The application of short fibers to a base fabric by the direct printing of adhesive onto the fabric in the desired areas and then sticking the fibers to these areas.

34. What is geo-textile?

A textile used in soil based applications such as road building, dams and erosion control.

35. What is grey cloth?

Un-dyed and unfinished fabrics straight from the loom are known grey cloth or grey fabric.

36. What is industrial textile?

Textile product group that includes car tyres, medical textiles, geo-textile, conveyor or bet, car safety belts and parachute cord.

37. What is voile?

Light weight, open plain weave is known as voile.

38. What is tie dye?

It is a method of patterning fabric by tyring areas of fabric and then dyeing.

39. What is stentering?

A controlled straightening and stretching process.

40. What is screen printing?

It is a method of printing whereby the color is applied by what is essentially a stenciling process.

41. What is roller printing?

It is a method of printing fabric that uses engraved copper rollers.

42. What is over dyeing?

When dyeing take place on top of a previous coloring process.

43. What is furnishing?

Product group including curtains, upholstery fabrics, carpets and wall coverings.

44. What is crocking?

It is the method of transferring color by rubbing.

45. What is all over design?

Design with balanced motifs that recure regularly within the repeat unit. The motifs cover the fabric with little ground showing.

46. What do you mean by balanced color way?

When the colors change but total relationships of the color within the deisgns stay the same, giving the same overall visual effect.

47. What do you mean by dyeing assistance?

The assistance which are added in dyeing bath for which dyeing affinity is increased is known as dyeing assistance.

48. What is chromophore?

The part of the molecular structure of an organic dye or pigment responsible for color is known as chromophore.

49. What do you mean by C.M.S?

In textile dyeing industry, C.M.S stands at carboxyl methyl cellulose.

50. What is the abbreviation of T.R.O?

The abbreviation of T.R.O is Turkey red Oil.

51. Give the chemical classification of disperse dye .

Ans: 1. Azo dyes, 2. Anthraquine dyes.

52. 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).

53. Which dispersing agents are used in disperse dyeing?

Ans: Soap, T.R.O oil, Formaldehyde etc.

54. Give some trade name of dispersing agent?

Ans: Setamol (BASF), Edamol (Sandoz), Hispogal (Hoescht).

55. What is carrier?

Ans: Carriers are dyeing assistants which alter the

dispersing properties of the dyes and physical

characteristics of the fibre.

56. 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.

57. What are the methods of application of sulpher dyes?

Ans: Fabric preparation > Preparation of sulpher dye >

Dyeing > Oxidation > after treatment > Dyed goods.

58. What are the defects of sulpher dye?

Ans: 1. Bronziness, 2. Tendering.

59. How azoic dyes are produced?

Ans: By reaction of two components Diaz component (Salt/

Base) and Coupling component (Napthol).

60. What are the different names of azoic dye?

Ans: 1. Ice color, 2. Magic color, 3. Napthol color, 4.

Pigment color.

Basic Viva For Textile Engineers (Dyeing Related) Part-4

 

91. Why binder is used in pigment printing?

Ans: For consist the dye in the surface of fabric.

92. What is the difference between dye & pigment?

Ans: Dye is soluble & pigment is insoluble.

93. What is styles of printing?

Ans: 1.Direct printing, 2.Discharge printing, 3.Resist printing

94. At WTP which part of hardness is removed?

Ans: Positive part (Ca+)

95. At WTP which part of hardness is not removed?

Ans: Negative part (CO3-)

96. Which part gives greater hardness?

Ans: Negative part.

97. What is half emulsion?

Ans: Emulsion thickeners are often mixed with carbohydrate

paste to give so called half emulsion.

98. 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.

99. 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.

100. 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.

101. 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 .

102. What is the squeeze systems used in rotary screen printing machine?

Ans:

Rubber Squeeze.

Double Squeeze.

Magnetic rod Squeeze.

103. What are the advantages of rotary screen printing machine?

Ans:

High productivity.

Quality of end result.

Evenness of color.

104. What is the squeeze systems used in Flat screen printing machine?

Ans: Parallel rubber blades.

105. 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.

106. 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.

107. What is substantivity?

Ans: The attraction between a substrate and a dye

molecule.

108. 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.

109. 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.

110. 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.

111. 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.

112. 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.

113. What is the end use of silk ?

Ans: End uses: Used in highly demanded cloths, Furnishing

in different curtains and In the sharee.

114. 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.

115. 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.

116. Mention the major silk producing country?

Ans: Producing country: People’s Republic of china, Japan,

Korea, Soviet Union, India, Italy, France, & the Hungary.

117. Mention the natural filament?

Ans: Silk, Mohair, Cashmere, Camels, hair, Alpaca, Angora,

Lama, Vicuna, & Gunaco Etc.

118. What are the end use of wool fibre?

Ans; Luxury coating, Sweaters, Shawls, Suit and dress

fabric.

119. What type of dyes are used for wool dyeing?

Ans; Easy to dye, Acid, Mordant or chrome, prematalized,

reactive, dye stuff is Suitable.

120. Briefly discuss the anionic polymerization process with example?

Ans: Anionic polymerization process are given below;