The Introduction of Coloration and Finishing

Q1)What are the general purposes of textile coloration?

Color is one of the most significant factors in the appeal and marketability of textile products. Textile coloration is used to enhance the aesthetics and beautification.

Q2)Briefly describe how to complete an exhaust dyeing process?

Exhaust dyeing is a kind of batchwise dyeing. It dyes in rope form by using Overflow/Jet Dyeing Machine or dyes in open width form by using beam dyeing machine.

First, choose a dyeing machine based on the fabric dyeing form. We should remember the fabric wight before dyeing which is going to be dyed and then calculate dyestuff weight on weight of fabric weight in percentage. Also, we have to calculate the water amount based both the fabric and machine to get the liquor ratio. In dyeing process, salt, soda ash and dyestuff are needed. Putting leveling agent or not is optional. Those chemicals help us to dye to color into the fabric and fix the color. We have to calculate the chemicals we used. After finished all the calculation, we can put fabric and all chemicals into the dye bath to start the dyeing.

During the dyeing process, we should control the pH of dyeing solution. And keep temperature about 60 degree and the dyeing time around 60 to 120 minutes to make sure the fabric can dye evenly.

Q3)Explain the meanings of the following terms: affinity, dye substantivity, compatibility of dye, dyeing exhaustion, liquor ratio, pick-up ratio, continuous pad dyeing, yarn package dyeing, surfactant, vat dyes.

Affinity :

It is a natural attraction. The tendency of chemical attraction or force between dye and textile that cause them to combine. Or we think it is the dye absorbing capacity of textile fibres, yarn, fabrics.

Dye substantivity :

The affinity of a dye for a given textile.

Compatibility of dye :

Dye have the similar properties and similar dyeing behavior, including tone-on-tone build-up properties, equal robustness to different dyeing conditions, and no blocking effect between them.

The compatible dyes with each other are ideal for use in color mixtures, since color is matched with3 dyes in usual.

Dyeing exhaustion :

It also can called batchwise  dyeing. It is the dyeing process that textile absorbing dye in solution until reaches equilibrium and fixation is completed

Liquor ratio :

The ratio of the weight of the dry material being dyed to the water weight of an exhaust dye bath.

Pick-up ratio :

The ratio of the weight of the dye solution absorbed on the fabric after squeezed by paddlers to the weight of dry.

Continuous pad dyeing :

The greige or un-dyed piece fabric passes through a dye bath to absorb dyestuff. Then the fabric is squeezed between padding rollers to remove extra dye solution and ensure even and consistent dyeing. Combining different machine, such as steaming and washing, into a sequence to complete the whole dyeing process.

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