ISO 22195-5:2021

Textiles - Determination of index ingredient from coloured textile - Part 5: Lac

This document specifies a test method which identifies the index ingredient chemical included in coloured fabric with lac. Lac can be applied to both natural fibre and man-made fibre.

Textiles — Détermination d'indicateurs d'ingrédients de textiles colorés — Partie 5: Gomme-Laque

General Information

• Status: Published
• Publication Date: 08-Nov-2021
• ICS: 59.080.01 - Textiles in general
• Technical Committee: ISO/TC 38 - Textiles
• Drafting Committee: ISO/TC 38/WG 31 - Natural material for textiles
• Current Stage: 6060 - International Standard published
• Start Date: 09-Nov-2021
• Due Date: 12-Jul-2021
• Completion Date: 09-Nov-2021

Overview

ISO 22195-5:2021 sets the international standard for identifying the index ingredient chemical-laccic acid C-within coloured textiles dyed using lac dye. This test method applies to both natural fibers and man-made fibers coloured with lac, a natural resinous secretion from lac insects (Kerria lacca). The standard is part 5 of the ISO 22195 series focusing on the determination of natural colourants in textiles.

Accurate identification of lac dye is essential for verifying natural dye claims, which are increasingly important for environmental sustainability in textile production. This method uses chromatographic analysis (HPLC-PDA) to extract and detect laccaic acid C, the key chemical marker of lac dye.

Key Topics

• Scope and Application
  Targets textiles coloured with lac dye on both natural and synthetic fibers. Establishes a reproducible procedure to identify the index ingredient chemical from coloured fabrics.

• Principle
  Lac dye contains a unique chromophore-laccaic acid C-that can be chemically extracted from textiles and detected by high performance liquid chromatography using a photodiode array detector (HPLC-PDA).

• Reagents and Apparatus
  Requires analytical-grade solvents such as acetonitrile, dimethylformamide (DMF), and trifluoroacetic acid. Essential equipment includes an ultrasonic bath for extraction, membrane filters, and HPLC-PDA system.

• Test Procedure

  1. Sample preparation by cutting textile into small pieces.
  2. Extraction of the lac dye using DMF in an ultrasonic bath.
  3. Filtration of the extract and analysis by HPLC-PDA, comparing retention time and absorbance with a laccaic acid C standard.
  4. Qualification based on chromatographic matching confirms lac presence.

• Test Reporting
  Comprehensive test report must include references, sample details, chromatographic conditions, results, deviations from procedure, and test date.

Applications

• Textile Quality Control
  Enables textile manufacturers and laboratories to verify natural dye usage, particularly lac dye, guaranteeing authenticity.

• Environmental Verification
  Supports environmental claims by confirming the use of natural lac dyes, which are valued for lower ecological impact compared to synthetic dyes.

• Cultural Heritage and Conservation
  Assists in scientific examinations of historical textiles, artworks, and manuscripts to identify natural lac-based colorants.

• Regulatory Compliance
  Provides standardized methods for regulatory agencies and certification bodies assessing natural dye content in textile products.

Related Standards

• ISO 22195 Series
  Covers the determination of index ingredients from various coloured textiles with natural dyes.

• ISO 3696: Water for analytical laboratory use
  Specifies quality requirements for water used in analysis, referenced for reagent preparation.

• ISO/IEC Directives Part 1 & 2
  Governs the editorial rules and development processes for ISO standards, ensuring consistency and clarity.

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By implementing ISO 22195-5:2021, textile professionals can reliably detect lac dye presence using scientific extraction and chromatographic analysis methods. This enhances product transparency, supports sustainable textile practices, and preserves the integrity of textiles dyed with traditional natural colorants.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 22195-5
First edition
2021-11
Textiles — Determination of index
ingredient from coloured textile —
Part 5:
Lac
Textiles — Détermination d'indicateurs d'ingrédients de textiles
colorés —
Partie 5: Gomme-Laque
Reference number
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
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or ISO’s member body in the country of the requester.
ISO copyright office
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Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents . 2
6 Apparatus . 2
7 Procedure .2
7.1 Standard preparation . 2
7.2 Preparation of specimen . . 2
7.3 Analysis . 3
7.4 Qualification of laccaic acid C . 3
8 Test report . 3
Annex A (informative) Example of test result . 4
iii
Foreword
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electrotechnical standardization.
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different types of ISO documents should be noted. This document was drafted in accordance with the
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This document was prepared by Technical Committee ISO/TC 38, Textiles.
A list of all parts in the ISO 22195 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
There is no doubt that dyeing plays the most important role in expressing the colour of clothes. Until
the invention of synthetic dyes capable of expressing diverse colours today, humankind used materials
obtained from nature to dye fabric. Typically, colourants were obtained from plants or various materials
were extracted from minerals or insects. Dyeing fabrics using materials derived from these natural
substances made it necessary to identify which substances the colourant was derived from. In other
words, there has been a demand to confirm whether a fabric has been dyed with a natural substance.
There are several natural dyes raw material which give similar colour tone, they have different colouring
molecule and the precise colorant. But each has different environmental profile which decided
Environment impact of dyestuff. Textile dyed with natural dyes is claimed for environmental benefit
mainly. Identification of dye helps in knowing and verifying the claims, that will help environment to
get benefit
...