ISO 5432:2022

Leather - Wet blue sheep skins - Specification

This document specifies requirements, sampling methods and testing methods for wet blue leather produced from sheep skins tanned without wool and with the use of basic chromium sulfate as the primary tanning agent.

Cuir — Peaux d'ovins à l'état «bleu humide» — Spécifications

General Information

• Status: Published
• Publication Date: 17-Nov-2022
• ICS: 59.140.30 - Leather and furs
• Technical Committee: ISO/TC 120/SC 2 - Tanned leather
• Drafting Committee: ISO/TC 120/SC 2 - Tanned leather
• Current Stage: 6060 - International Standard published
• Start Date: 18-Nov-2022
• Due Date: 09-Aug-2022
• Completion Date: 18-Nov-2022

Relations

• Revises: ISO 5432:2013 - Leather - Wet blue sheep skins - Specification
• Effective Date: 17-Jul-2021

Overview

ISO 5432:2022 is an international standard specifying the requirements, sampling methods, and testing procedures for wet blue leather produced from sheep skins. This leather is tanned primarily using basic chromium sulfate without wool and is widely used in the leather industry for its quality and durability. The standard ensures consistency, safety, and quality across producers and suppliers by defining strict chemical, physical, and presentation criteria.

Key Topics

• Raw Material
  Wet blue sheep skins must be processed from cured or fresh sheep skins and free from wool.

• Tanning Process
  Uses basic chromium sulfate as the primary tanning agent, with complete chromium penetration in the leather and a tanning pH of 3.0 or above.

• Chemical Requirements

  • Volatile matter to exceed 50% of dry leather mass
  • Matter soluble in dichloromethane less than 4%
  • pH of water extract at least 3.2
  • Chromic oxide content no less than 3.0% of dry mass to ensure durability and proper tanning

• Fungicidal Additives
  Use of effective fungicides to inhibit mould growth and pigmentation during storage and transportation, maintaining leather quality for up to 4 months.

• Physical Quality
  Leather should have a tight grain, be free from creases, drum folds, and stains caused by iron or chromium salts, with at least 95% of skins free from such defects.

• Shrinkage Temperature
  A minimum shrinkage temperature of 95 °C, ensuring thermal stability of the wet blue sheep skins.

• Sampling and Testing
  Defined procedures for routine and dispute sampling, along with methods for assessing color uniformity, chromium sulfate penetration, shrinkage temperature, pH, volatile matter, fungicide effectiveness, and chemical residuals.

• Packaging and Marking
  Packaging must preserve the original wet condition of the skins, and labeling must include material type, manufacturer details, tanning date, quantity, and purchaser-specific information.

Applications

ISO 5432:2022 serves multiple practical uses in the leather manufacturing and supply chain:

• Quality Control: Provides measurable criteria for raw material inspection and quality assurance in tanneries producing wet blue sheep leather.
• Supplier Agreements: Defines clear terms for product acceptance between purchasers and suppliers, including agreed tolerances on chemical content and physical defects.
• Storage and Transportation: Guidelines on fungicide use help preserve leather during transit and storage, preventing quality degradation by mould.
• Testing Laboratories: Standardizes chemical and physical test methods, enabling consistent laboratory assessments across the global leather industry.
• Regulatory Compliance: Supports adherence to international trade and chemical safety regulations by defining permissible chemical levels and testing protocols.

Manufacturers and suppliers across the leather production chain, from raw skin processing to finished goods, rely on ISO 5432:2022 to ensure product reliability and international market acceptance.

Related Standards

ISO 5432:2022 references and complements several other standards critical to leather processing and testing:

• ISO 2418 – Sampling location for chemical, physical, mechanical, and fastness tests on leather
• ISO 3380 – Determination of shrinkage temperature of leather
• ISO 4044 & ISO 4045 – Preparation of chemical test samples and determination of pH
• ISO 4048 – Determination of matter soluble in dichloromethane and free fatty acid content
• ISO 4684 – Determination of volatile matter in leather
• ISO 5398-1 – Quantification of chromic oxide content by titration
• ASTM D4576 – Test methods for mold growth resistance of wet blue leather

Adhering to this suite of standards ensures comprehensive quality control, safety, and performance evaluation for wet blue sheep skins, promoting global consistency in leather production and trade.

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Keywords: ISO 5432:2022, wet blue sheep skins, leather specification, chromium tanning, fungicidal additives, shrinkage temperature, chemical testing, leather quality, sampling methods, leather industry standards, chromic oxide content, leather packaging, leather testing methods.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 5432
Third edition
2022-11
Leather — Wet blue sheep skins —
Specification
Cuir — Peaux d'ovins à l'état «bleu humide» — Spécifications
Reference number
© ISO 2022
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
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
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
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Requirements . 2
4.1 Raw material . 2
4.2 Tanning . 2
4.3 Fungicidal additives . 2
4.4 Presentation . 2
4.5 Shrinkage temperature . 2
4.6 Chemical requirements . . 2
5 Sampling . 3
5.1 Sampling for routine testing . 3
5.2 Sampling in cases of dispute . 3
5.3 Preparation of samples . 3
6 Method of testing . 3
6.1 Visual tests . 3
6.2 Shrinkage temperature . 3
6.3 Volatile matter . 4
6.4 pH of the water extract . 4
6.5 Effectiveness of the fungicide . 4
6.6 Determination of matter soluble in dichloromethane . 4
7 Packaging and Marking . 4
7.1 Packaging . 4
7.2 Marking . 4
Bibliography . 5
iii
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