Comments on: Cross-Shade Variation (CSV) In Indigo Dyeing : Causes and Solutions

By: kiran

kiran — Thu, 05 May 2011 04:35:05 +0000

i waana know is there any recipie for removing the indigo dye from yarn??? if any plz tell me

By: abhi

abhi — Sat, 30 Apr 2011 08:11:17 +0000

Hi Harry,

Need to know a bit about denims.

I am from India, and recently imported some B grade denim from Pakistan on cheap rate.

Need to know what is the problem in using B grade denim. and what difference it makes between A grade and B grade denim.

Please advice.

Regards
Abhishek Anand

By: md rafiqul alam

md rafiqul alam — Mon, 12 Jul 2010 07:57:20 +0000

Hi mercer,
about keeping the concentration in the dye box consistent and also shade,needs to check also following parameters:
1.nip pressure/squeezing(it controls pick up of each box)
2.ph(MONOPHENOLATE/DYEPHENOLATE FORM OF INDIGO,DEPENDS ON WASH DOWN EFFECT,PH BETWEEN 11-11.80)
and
3.redox value.(degree of vatting,partial/full reduction of indigo,-700 to 800 mv).

I m from bagladesh,an indigo dyeing and processing researcher at a technical university in bangladesh.
Could u give me an idea about black dyeing and black topping i,e hw many dye boxes i can use in topping and black dyeing and what is the maximum % of black dye and also concentration in dye box
that I can be dyed with consistent shade and also give me an idea about black fixation if u wish?Expecting ur coordial reply.
rgds
rafiq

By: Harry Mercer

Harry Mercer — Sun, 20 Jun 2010 14:25:58 +0000

Hi Paulo:
That is a good point. The number of dye boxes is related to the maximum anount of Indigo that can be applied to cotton consistantly. A general rule is that the amount of Indigo that is easily soluble in a dyebox is approximately 2 grams of Indigo per kilogram of yarn. In the U.S. normally 6 boxes were used to apply a total of 12 grams of Indigo per kilogram of yarn for 1.2% total Indigo on weight of yarn. With U.S. dyeing methods, this was adequate for a dark shade. A super dark shade was made with 1.6%. When I started consulting in the 1990’s, I was surprised that for the same depth of shade that we had in the U.S. with 1.2% Indigo, in Latin America the methods used required 2.0% Indigo and in Asia 2.4% was applied.
Once you try to apply more Indigo than 2 grams per box per kilogram the dyebath becomes unstable and shade variation begins. In India a few years ago, I devised a change in dyeing on a rope range using 1.8% that produced a darker Indigo shade than the 4% application using the methods recommended by the dye company.

Regards,

Harry Mercer

By: Paulo Ferreira

Paulo Ferreira — Fri, 18 Jun 2010 15:42:06 +0000

Hi Harry, some sugestions for the sheet ranges might be to dye with the maximum numeber of dye vats, today it is common ranges with 10 dye vats. Another sugestion is to use a dye range with a smaller with so the possibility of variation will be reduced or eliminated.
Paulo Ferreira – Brazil