1. Abstract
Often people ask about the problems encountered in dyeing bright blue shades on cellulosic substrates, particularly cotton and viscose. The following question comes from Dyehouses in Peru and Brazil.
"We are having problems dyeing bright blue shades. We can see red areas across and throughout the fabric. Do you know what could be the problem?"
This article seeks to consider some of the critical issues involved.
2. Full Article
2.1 The Solution
The solution comes from the Dye House Solution as follows
There are many examples of such patchy red areas in dyeing with reactive bright blue dyes.
However, they have diagnosed different origins to each problem. Each case must be treated on its individual merits. Some clues as to the origin of the problem can be gleaned by circumstances surrounding the observed problem.
2.2 Most Widely Used Dyes
Table 1: Largest Global Dye Sales
CI Number
Major Brands / Suppliers
Chromophore
CI Reactive Blue 198
Procion Blue H-EGN
DyStar
Triphendioxazine
(TPD)
CI Reactive Blue 19
Remazol Br Blue R Special
Sumitomo
Anthraquinone
2.3 Shade Sensitivities of Bright Blue Reactive Dyes
2.4 Gas Fume Fading of Bright Blue Reactives
This is demonstrated below for the anthraquinone blue Remazol Br Blue R special (Fig 1)
Fig 1: CI Reactive Blue 19
The degree of fading / shade change can vary according to the state of the fabric. As noted earlier, substrates with an acidic pH. (See Table 2). Dyehouse management, good housekeeping practices and effective (and informed) supervision are therefore important.
Table 2: Gas Fume Fading and pH Sensitivity
Colour Fastness (Effect on Pattern) under different conditions of Test.
Dyestuff
pH of sample
No Neutralisation
WET
DRY
With Neutralisation
Blue 19
4.2
2
2-3
6.6
4
9.9
3-4
4-5
3
Blue 221
5
Blue 222
CI Reactive Blue 221 is Sumifix Supra Blue BRF. CI Reactive Blue 222 is Sumifix Supra Navy Blue BF. Both are blue dulling components which represent a standard blue and Navy response and are used to indicate increased sensitivity.
2.5 Concluding Remarks
o Low Substantivity (S)
o High Secondary Exhaustion (E-S)
o High Reactivity (R).
Fig 2: SERF of Remazol Br Blue R Special
o high yield in cloth
o brightness
o fastness properties.
2.6 "A Funny Thing Happened On The way to The Dyehouse"
Circumstances are not always what they appear from a distance (and what we are told by the Customer).
Case Study 1
Production Type: Exhaust Dyeing Cellulosic Knitgoods and Blends
Location: Israel
Customer Report: Unlevel Red patches.
Customer Diagnosis: Dyestuff at fault.
Facts: This same customer reported the same problem in the same month for each of the previous three years.
Inspection of Customer Premises: Dyehouse used water sourced from a well. Problem occurred in the month following an extremely dry period.
Observations: Water level in the Well extremely low. Seasonal occurrence, repeated annually. Extremely high levels of Ca and Mg for relatively limited periods of time, during which many dyes suffered.
Case Study 2
Production Type: Exhaust Dyeing Cellulosic Knitgoods and Blends.
Location: Barcelona
Customer Report: Unlevel Red patches. Problem only occurred with one dye (Procion Blue H-EGN). All other bright blue reactives passed laboratory screening test for gas fume fading.
Facts: On arrival, Barcelona (unusually) cold and covered in snow. Difficult to see anything in Dyehouse due to intense "fog".
Observations: Extractor fan above gas fired stenter not working. All windows closed because of cold conditions. Extremely high build up of nitrogen oxides, well in excess of laboratory gas fume fading test. Dyeings of all available dyestuff options hung on Dyehouse wall. All reduced to a virtual white in relatively short time.
Recommendation: Leave dye selection as it is and (in the short-term) open the windows. Replace extractor fan above stenter. Schedule production so that all bright blue shades dried on other stenter available (oil fired). Ensure that all trucks of wet fabric waiting for drying are effectively covered to exclude exposure to fumes (especially bright blues). All recommendations gratefully accepted.
2.7 Epilogue
Sometimes being right on top of a problem, can lead to restricted vision. And it can happen to any one of us. None of us is immune. There is nothing clever about a "fresh pair of eyes" to look at a problem. But the emphasis on fresh is important.
--------x-------
Responsibility:
Fibre2fashion.com does not warrant or assume any legal liability or responsibility for the excellence, accurateness, completeness, legitimacy, reliability or value of any information, product or service represented on Fibre2fashion.com. The information provided on this website is for educational or information purposes only. Anyone using the information on Fibre2fashion.com, does so at his or her own risk, and by using such information agrees to indemnify Fibre2fashion.com, and its content contributors from any and all responsibility, loss, damage, costs and expenses (including legal fees and expenses), resulting from such use.
No Endorsement:
Fibre2fashion.com does not endorse or recommend any article on this site or any product, service or information found within said articles. The views and opinions of the authors who have submitted articles to Fibre2fashion.com belong to them alone and do not reflect the views of Fibre2fashion.com.
If you wish to reuse this content on web, print or any other form, please seek for an official permission by writing to us on editorial@fibre2fashion.com
Subscribe today and get the latest information on Textiles, Fashion, Apparel.
Download Free Report
Rising Opportunities in Technical Textiles Market: 2020-2026
Thank you for showing interest in our free report on 'Rising Opportunities in Technical Textiles Market: 2020-2026'
You will receive an email shortly with a link to download the report and in case if you don't receive our email, you can write back to texpro@fibre2fashion.com.
Thank You!