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.