Case Study on Chemical Performance Improvement Hard Goods Suppliers

How NimkarTek helped a Brand’s hard goods suppliers improve their chemical performance by implementing Chemical Management systems.

The Requirement

To implement best chemical management systems by providing knowledge and awareness in the chemicals area for a Brand’s hard goods suppliers.

The Solution
  • Training
  • On-site assessments
  • Implementation of Chemical management systems
  • Re-assessment

The Background

A Brand wanted their hard goods suppliers to improve their chemical performance and compliance. These suppliers were not aware about chemical management and had only the basic systems in place.

NimkarTek was required to implement Chemical Management in these supplier units.

These facilities were suppliers of Hard Goods –

  1. Glass
  2. Metals
  3. Wood
  4. Wax
  5. Shoes
  6. Leather and PU accessories

The Objective

Picture2Implement Chemical Management systems at the supplier facilities by providing tailor-made forms and formats, hand hold these suppliers and implement best practices in the industry.

The Process

  • NimkarTek kick-started the project by conducting a one-day, in-person training workshop for all facilities.
  • An on-site assessment of each facility was conducted to understand their current systems in chemical management. Subsequently, a report with areas of improvement was sent to each facility.
  • Each facility set up a ‘Chemical Management Team’ who were responsible in implementing Chemical Management Systems.
  • Guideline documents for implementing systems for chemical management were sent to the team members.
  • NimkarTek conducted webinars for communicating with each supplier and doubt-solving.
  • After 4 months, NimkarTek carried out re-assessment to map the improvements made.

Chemical Management Systems

The following Guideline documents were provided to each facility –

  • Shop Floor improvements – Focus was on worker health and safety
  • Chemical Management Team – Roles and responsibilities of each team member
  • Chemical Management Manual – Development of a facility specific chemical management manual.
  • Purchasing practices – Provide restricted substance specification to chemical suppliers.
  • Supplier Declarations – A standard format was developed as per each facility’s requirement.
  • Chemical hazard labeling – Focus was on worker health and safety
  • Personal protective equipment
  • Chemical Storage and handling best practices

The Outcome

The Chemical Management assessments at each facility have led to a better understanding of the complex subject of chemical management and have resulted in better compliance performance from these facilities.

  • A dedicated chemical management team, along with a technical representative were set up in each facility.
  • All facilities fulfilled the Brands Chemical Management requirements.
  • All facilities developed a good understanding of chemical related documentation such as MSDS, TDS, hazard labeling systems and supplier declarations for compliance.
  • Facilities developed a chemical management policy with an internal audit practice to measure continuous improvements.
  • Chemical Inventory was studied and mapped for presence of harmful chemicals.
  • Chemical risk assessment and precautionary actions for storage, handling and phase-out of harmful chemicals were implemented.

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Case Study on Banned Amines

Case Study on Banned Amines

Root Cause Analysis of 4, 4’-diaminodiphenylmethane (a banned amine) in “wave” dyed garment


A “wave” dyed garment manufactured by a reputed garment manufacturer in Sri Lanka tested positive for the presence of 4, 4’-diaminodiphenylmethane (a banned amine). The Sri Lankan garment manufacturer approached NimkarTek to investigate the issue and find out the root cause of this failure. NimkarTek worked on this case and found out the root cause of the failure.

Step-by-Step Investigation Done by NimkarTek:

  • Step 1: All the processes used for the manufacturing of the wave dyed garment were mapped as follows:
    • Stage 1: Garment dyed with reactive dyes
    • Stage 2: Dyed garment overprinted with pigment
    • Stage 3: Overprinted garment subjected to wave dyeing treatment
  • Step 2: The garment produced after each of these processes was tested for the presence of banned amines as shown below:

Wave Dyeing Sequence

Test results showed that the garment produced after Stage 1 and Stage 2 did not contain banned amines. However, after Stage 3, the garment tested positive for the presence of a banned amine. This confirmed that the banned amine contamination might have orignated from the chemicals used in Stage 3 process i.e. Wave dyeing process.

  • Step 3: All the chemicals used in the wave dyeing process were mapped and listed as follows:
    • Catalyst to reduce fixation temperature
    • Enzyme
    • Synthetic co-polymer resin
    • Silicone softener
    • Cationic Softener
    • Microsilicone emulsion
    • Blue Pigment
  • Step 4: Based on the chemistry of the chemicals used (where amine release could be possible), following 3 input chemicals were tested for the presence of banned amines:
    • Pigment
    • Resin
    • Catalyst


Out of these, the catalyst used to reduce fixation temperature was found to contain 0.14 % of 4, 4’-diaminodiphenylmethane. The root cause of this banned amine failure was thus the catalyst used in the wave dyeing process. The Catalyst used in the wave dyeing treatment was based on Polyurethane, which on hydrolysis, can release 4, 4’-Diaminodiphenylmethane. This reaction mechanism occurs under acidic reducing conditions which are exactly the conditions used in the test method for banned amines!

Such results are known as “False Positive” results for banned amines, since the banned amine is detected due to reasons other than cleavage of the azo bond (-N=N-) in a colorant.

Corrective Actions Taken:

The garment manufacturer was advised by NimkarTek to replace the catalyst used in the Wave Dyeing process with a Polyurethane (PU) –free alternative to avoid this problem. The matter was discussed with the chemical supplier of this garment manufacturer and a PU- free catalyst was substituted in the wave dyeing process.

Nimkartek has developed a complete online course to Understand the Banned Amines. The ‘Introduction to Banned Amines’ module introduces you to Azo colourants and banned amines. It describes how these amines are released from azo dyes. The module then discusses why some these amines are restricted and briefly lists their sources in Textile and Leather processing. The module describes the Global regulations on banned amines and then enlists the precautions that must be taken for ensuring Banned amine compliance.

To see a trailer of the course you can see this video:

You can take this course right away and improve your understanding on the banned amines and their compliance in the textile manufacturing.

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The Curious Case of Mr Banned.A.Mine

The Curious Case of Mr Banned.A.Mine

At NimkarTek, some cases of failures to Restricted Substances in textile articles require to be investigated like Sherlock Holmes, the fictional detective character created by Sir Arthur Conan Doyle. The skills of Holmes –which include astute logical reasoning and use principles of science to solve difficult cases – were put to use by us in a curious case of a failure to a Banned Amine in a garment that was subjected to a new washing trend called “Wave Dyeing”.

Like Sherlock Holmes would have explained to Dr Watson, let me first lay out the basic facts of the case.

There are certain dyes based on an ‘Azo’ chemistry which can cleave and release certain ‘amines’ (chemicals with a particular structure) which are now proven to be carcinogenic, that is, cancer- causing. These azo dyes are certain Direct dyes, Acid dyes or Pigments that are used in the coloration of textile articles. Such colorants are banned or restricted for use by global legislations and by Brands & Retailers.

Wave dyeing is a new washing technique applied on garments to give it a spray or ‘peppery’ look, using certain auxillaries and pigments in the finishing process of the garment.

NimkarTek was approached by a garment manufacturer in Sri Lanka that such wave dyed garments shipped from their factory were rejected by their Buyer for presence of a certain Mr Banned Amine called 4, 4’-Diaminodiphenylmethane. The process involved dyeing the garment with reactive dyes, then overprinting with pigments and further subjecting it to the ‘wave dyeing’ finishing process. The final garment tested positive for presence of the banned amine 4, 4’-Diaminodiphenylmethane. The concentration of the banned amine detected was varying in different parts of the garment.

Since banned amines are released from certain azo colorants, the needle of suspicion pointed to the reactive dyes and pigments used in the process stages prior to wave dyeing treatment. Hence, we took a sample of only reactive dyed garment and a sample of (reactive dyed + overprinted with pigment) fabric for testing. To our surprise, both these samples did NOT test positive for any banned amine! But after wave dyeing treatment, the garment showed presence of the banned amine – where actually no colorant was used. The case was becoming curious!

We then looked at the chemicals that were used in the Wave Dyeing finishing treatment, which included a resin, a ‘special catalyst’, synthetic co-polymer, silicone softener and cationic softener in the finishing mixture. Going deeper into the chemistry of these chemicals, it was decided to test only the Catalyst for presence of the banned amine.

Lo and behold, the Catalyst detected 0.14% of the culprit 4, 4’-Diaminodiphenylmethane! This catalyst was used as a cross-linker to favour curing of the resin at lower temperatures, and its actual presence on the garment depended on its pick-up on the garment. This was thus a curious case where a banned amine was detected not due to release from a colorant (as would have been expected) but from a reaction mechanism (under the test conditions for azo dyes) of a chemical used in the process!

In the end, it was “quite elementary, my dear Watson”, as Holmes would have put it.

The Catalyst used in the wave dyeing treatment was based on Polyurethane, which on hydrolysis, can release 4, 4’-Diaminodiphenylmethane. This reaction mechanism occurs under acidic reducing conditions which are exactly the conditions used in the test method for banned amines!

Such results are known as “False Positive” results for banned amines, since the banned amine is detected due to reasons other than cleavage of the azo bond (-N=N-) in a colorant.

As Sherlock Holmes tells Dr Watson in the book The Sign of the Four, “How often I have said to you that when you have eliminated the impossible, whatever remains, however improbable, must be the truth!”

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