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Friday, 10 November 2023

Different Dyes and Textile Fibres

 Reactive Dye: Applicable for cotton, linen, viscose, wool, silk. The dyestuff forms a chemical Link with the fibre. It has very good fastness properties

Disperse Dye: Applicable to polyester, nylon, acetate. It is water insoluble; applied' from dispersions; diffuse into the fibre at high temperature. It has also good fastness properties. 

Vat Dye: Applicable for cotton, linen, viscose. The insoluble dyestuff is made soluble in a reducing vat so that it can diffuse into the fibre. After diffusion is complete, it is then re-oxidized into it's insoluble form. It has high fastness to washing, chlorine, boiling, light, weather, rubbing and perspiration. 





Direct Dye: Applicable for cotton, linen, viscose, silk. Simple diffusion into the fiber, from aqueous solution. It has relatively poor fastness properties to light, washing, and perspiration. These fastness properties can be improved by after treatment. 

Basic Dye: It is suitable for acrylic fibres (other fibres by mordanting). It reacts with acidic groups or mordants (a chemical which can react or complex with a chromophore to form an insoluble color) in the fibre. It has good fastness properties on acrylic fibres.

Acid Dye: Applicable for wool, silk, nylon. Applied from an acidic dyebath. The fastness properties of this dye-stuff depend on the fibre type.

There are also some other dyestuffs such as sulfur, azoic, metal complex, chrome dyes etc

Thursday, 9 November 2023

Basic Viva For Textile Engineers (Fabric Related) Part-11

 

301. What are the reason of clothing?
Ans.
Modesty
Protection against adverse climate conditions
Adornment
Identification
Aristocratic reason

302. What the breaks that used to stop the loom?
Ans.
Mechanical
Pneumatic (used air)
Hydraulic (used liquid)

303. Some important terms -
* The ratio of RPM of crank shaft and bottom shaft is always 2:1
** RPM of crank shaft = PPM of the loom

304. Can we mount more than two shedding tappet in a loom?
Ans. No

305. What is dwell?
Ans. The stationary period of heald frames in open shed condition during which time, the shuttle travel from one side of the loom to the other side.

306. How many heald frames can be controlled by Dobby shedding mechanism?
Ans. Theoretically maximum 48 but practically 36 can be controlled. But for cotton yarn weaving 24 controlled.

307. Minimum how many heald frame is controlled by Dobby shedding?
Ans. Minimum 12.

308. Maximum how many heald frame is controlled by Jacquard shedding?
Ans. 1800

309. What is efficiency?
Ans. The weaving efficiency describes how effectively a set of looms work in normal working environment.

310. What is bastard reed?
Ans: A reed in which dent space at each side is slightly greater than in the center.

311. What is flat bed?
Ans: A bed which provides a flat surface in a same pane as the table in which it is mounted.

312. What is Brocade?
Ans: A woven, patterned fabric using multi-colored threads

313. What is Damask?
Ans: It is similar to brocade but is finer, thiner. A woven, patterned fabric, using all one color - think fancy white cloth napkins. Usually silk, linen, cotton, rayon or synthetic blends.

314. What is voile?
Ans: Soft fine sheer fabric.

315. What is worsted?
Ans: Fine closely-woven wool.

Flow Chart of Printing

 

Flow Chart of Printing 


Greycloth 
↓ 
Brushing and Shearing 
↓ 
Singeing 

Desizing 

Scouring 

Bleaching

Mercerizing 

Stentering

Washing 

Drying

Winding/Beaming 

Printing 

Finishing




Figure: Printing

Basic Viva For Textile Engineers (Fabric Related) Part-9

 

241. What is a wale?
Ans. A wale is a predominantly vertical column of intermeshed needle loops.

242. What is the first type of needle?
Ans. Bearded needle.

243. What is the problem of bearded needle?
Ans. Presser bar is used as closing elements.

244. What is the function of sinker that performed?
Ans.
loop formation
holding down
knocking over.

245. What is cam?
Ans. Cams are the devices which convert the rotary machine drive into a suitable reciprocating action for the needles or other elements.

246. Write down the types of cam.
Ans.
Engineering cam,
Knitting cam.

247. What is needle loop?
Ans. The needle loop is the basic unit of knitted structure.

248. Write down the types of clearing cam.
Ans.
Knit cam,
Tuck cam,
Miss cam

249. What is the basic knitting action of a needle?
Ans.
Rest position,
Opening,
Clearing,
Yarn feeding
Landing,
Knock over.

250. What is held loop?
Ans. A held loop is an old loop that the needle has retained

251. Where the interlock fabrics are used?
Ans. Under garments clothing.

252. Inter lock has the technical face of plain fabric on both side (yes/no).
Ans. Yes.

253. In interlock fabric, reverse or back loop is not seen (yes/no).
Ans. Yes.

254. Technical face & back is of different in single Jersey fabric (yes/no)
Ans. Yes

255. What do you mean by GSM?
Ans. Gram per square meter.

256. What do you mean by oz/sq. yd?
Ans. Ounce per square yard.

257. Where GSM is used?
Ans. The term GSM is popularly used in knitted industry because buying & selling are done on the basis of weight of the fabrics.

258. What is the GSM range for finer fabrics?
Ans. Below 150

259. What is the meaning of CVC & PC/TC?
Ans.
CVC = Chief value of cotton (i.e. cotton more than 50%)
PC/TC=Polyester&Cotton / Tetron & Cotton (i.e.polyester more than 50%)
83. What types of loops produce in knitting?
Ans. Interlocking or Interlooping loops.

260. Weft knitting produce in which form?
Ans. Tubular form.

261. In which/loop, shanks are above and heads are below?
Ans. Face loop.

262. What is sinker loop?
Ans. The loop that joins two adjacent needle loop.

263. What is the basic unit of knitted structure?
Ans. Stitch/loop

264. Legs or shanks are below and heads are above in back loop (Yes/No).
Ans. Yes.

265. In where alternate face and back loops produced by two sets needle?
Ans. Rib structure.

266. In interlock fabric, is back loop invisible?
Ans. Yes.

267. Which is the only movable cam in the cam box?
Ans. Stitch cam.

268. What is the principal element of knitting m/c?
Ans. Needle.

269. What fabric produced by adhesive and punching?
Ans. Non-woven fabric.

270. Write the process sequence of woven fabric production?
Ans.
(A) Yarn preparation
Winding
Drawing in and denting
Warping
Leasing
Sizing
Tyeing in / Knotting
(B) Weaving
(C) Inspection
(D) Folding
(E) Transfer to DPF (Dyeing, Printing & Finishing)

Wednesday, 8 November 2023

Basic Viva For Textile Engineers (Fabric Related) Part-10

 

241. What is a wale?
Ans. A wale is a predominantly vertical column of intermeshed needle loops.

242. What is the first type of needle?
Ans. Bearded needle.

243. What is the problem of bearded needle?
Ans. Presser bar is used as closing elements.

244. What is the function of sinker that performed?
Ans.
loop formation
holding down
knocking over.

245. What is cam?
Ans. Cams are the devices which convert the rotary machine drive into a suitable reciprocating action for the needles or other elements.

246. Write down the types of cam.
Ans.
Engineering cam,
Knitting cam.

247. What is needle loop?
Ans. The needle loop is the basic unit of knitted structure.

248. Write down the types of clearing cam.
Ans.
Knit cam,
Tuck cam,
Miss cam

249. What is the basic knitting action of a needle?
Ans.
Rest position,
Opening,
Clearing,
Yarn feeding
Landing,
Knock over.

250. What is held loop?
Ans. A held loop is an old loop that the needle has retained

251. Where the interlock fabrics are used?
Ans. Under garments clothing.

252. Inter lock has the technical face of plain fabric on both side (yes/no).
Ans. Yes.

253. In interlock fabric, reverse or back loop is not seen (yes/no).
Ans. Yes.

254. Technical face & back is of different in single Jersey fabric (yes/no)
Ans. Yes

255. What do you mean by GSM?
Ans. Gram per square meter.

256. What do you mean by oz/sq. yd?
Ans. Ounce per square yard.

257. Where GSM is used?
Ans. The term GSM is popularly used in knitted industry because buying & selling are done on the basis of weight of the fabrics.

258. What is the GSM range for finer fabrics?
Ans. Below 150

259. What is the meaning of CVC & PC/TC?
Ans.
CVC = Chief value of cotton (i.e. cotton more than 50%)
PC/TC=Polyester&Cotton / Tetron & Cotton (i.e.polyester more than 50%)
83. What types of loops produce in knitting?
Ans. Interlocking or Interlooping loops.

260. Weft knitting produce in which form?
Ans. Tubular form.

261. In which/loop, shanks are above and heads are below?
Ans. Face loop.

262. What is sinker loop?
Ans. The loop that joins two adjacent needle loop.

263. What is the basic unit of knitted structure?
Ans. Stitch/loop

264. Legs or shanks are below and heads are above in back loop (Yes/No).
Ans. Yes.

265. In where alternate face and back loops produced by two sets needle?
Ans. Rib structure.

266. In interlock fabric, is back loop invisible?
Ans. Yes.

267. Which is the only movable cam in the cam box?
Ans. Stitch cam.

268. What is the principal element of knitting m/c?
Ans. Needle.

269. What fabric produced by adhesive and punching?
Ans. Non-woven fabric.

270. Write the process sequence of woven fabric production?
Ans.
(A) Yarn preparation
Winding
Drawing in and denting
Warping
Leasing
Sizing
Tyeing in / Knotting
(B) Weaving
(C) Inspection
(D) Folding
(E) Transfer to DPF (Dyeing, Printing & Finishing)

Tuesday, 7 November 2023

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.

Monday, 6 November 2023

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.

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