ISO 4045:2018

Leather - Chemical tests - Determination of pH and difference figure

This document specifies a method for determining the pH value and the difference figure of an aqueous leather extract. It is applicable to all types of leather.

Cuir — Essais chimiques — Détermination du pH et de l'indice de différence

Le présent document spécifie une méthode de détermination de la valeur du pH et de l'indice de différence d'un extrait aqueux de cuir. Il est applicable à tous les types de cuir.

General Information

• Status: Published
• Publication Date: 07-May-2018
• ICS: 59.140.30 - Leather and furs
• Technical Committee: IULTCS - International Union of Leather Technologists and Chemists Societies
• Drafting Committee: IULTCS - International Union of Leather Technologists and Chemists Societies
• Current Stage: 9093 - International Standard confirmed
• Start Date: 26-Mar-2025
• Completion Date: 30-Oct-2025

Relations

• Consolidates: ISO 10494:2018 - Turbines and turbine sets - Measurement of emitted airborne noise - Engineering/survey method
• Effective Date: 06-Jun-2022
• Revises: ISO 4045:2008 - Leather - Chemical tests - Determination of pH
• Effective Date: 06-May-2017

Overview

ISO 4045:2018 specifies a standardized chemical test method for determining the pH value and difference figure of aqueous leather extracts. This method is universally applicable to all leather types and is essential for assessing the chemical properties of leather in quality control, research, and manufacturing environments. The standard ensures consistency in testing leather samples by defining detailed procedures for sample preparation, measurement, and reporting.

Key Topics

• pH Measurement of Leather Extracts
  The standard outlines how to prepare an aqueous extract from leather samples and measure its pH using a calibrated pH meter. Accurate pH measurement is critical for evaluating leather quality, as pH affects leather processing, durability, and product performance.

• Difference Figure Determination
  The difference figure is calculated by comparing the pH of the original extract with that of a tenfold diluted extract. This figure provides insights into the presence of free strong acids or bases in the leather, helping differentiate between strong and weak acid/base contributions.

• Sample Preparation and Handling
  ISO 4045:2018 emphasizes proper sample sampling, preparation per ISO 4044, and duplicate testing to ensure reliable results. It specifies parameters such as sample mass, extraction time, temperature, and shaking method to standardize the aqueous extraction process.

• Equipment and Reagents
  The document details apparatus requirements including a calibrated pH meter with a glass electrode, analytical balance, shaker, and volumetric instruments. It also specifies reagent quality, particularly water conforming to ISO 3696 standards, and buffer solutions for calibration.

• Calibration and Accuracy
  Calibration of the pH meter is mandatory before testing with at least two buffer solutions bracketing the expected pH value. This practice guarantees accuracy within ±0.02 pH units and ensures reproducibility of measurements.

Applications

• Leather Quality Control
  pH and difference figure determination are vital tests during leather production and finishing. They help detect chemical imbalances, monitor tanning processes, and prevent defects caused by inappropriate acidity or alkalinity levels.

• Material Research and Development
  Leather technologists and chemists use this standard test to evaluate new formulations, tanning agents, and processing methods, ensuring compatibility and stability of leather materials.

• Regulatory Compliance and Trade
  Providing consistent and internationally accepted test results facilitates compliance with buyer specifications, supports certification processes, and reduces technical barriers in leather trade.

• Environmental Monitoring
  Measuring leather extract pH also aids in assessing potential environmental impacts from tanning and finishing chemicals, contributing to sustainable manufacturing practices.

Related Standards

• ISO 2418 - Leather Sampling Location
  Defines procedures for representative leather sampling, which directly supports sample integrity for pH testing.

• ISO 3696 - Water for Analytical Laboratory Use
  Specifies minimum water quality for preparing extracts and buffer solutions, crucial for test accuracy.

• ISO 4044 - Preparation of Chemical Test Samples
  Details the preparation of leather samples, including conditioning and cutting, prior to chemical testing under ISO 4045.

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Keywords: ISO 4045:2018, leather pH test, leather chemical analysis, difference figure, aqueous leather extract, leather quality control, leather testing standard, ISO leather testing, pH meter calibration, leather sample preparation, leather chemistry

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 4045
IULTCS/IUC 11
Third edition
2018-05
Leather — Chemical tests —
Determination of pH and difference
figure
Cuir — Essais chimiques — Détermination du pH et de l'indice de
différence
Reference numbers
IULTCS/IUC 11:2018(E)
©
ISO 2018
IULTCS/IUC 11:2018(E)
© ISO 2018
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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved

IULTCS/IUC 11:2018(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents . 1
6 Apparatus . 2
7 Sampling and preparation of the samples . 2
8 Procedure. 2
8.1 Preparation of the extract . 2
8.2 Calibration of the pH meter . 3
8.3 Determination of the pH value . 3
8.4 Determination of the difference figure. 3
9 Test report . 3
IULTCS/IUC 11:2018(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: www .iso .org/iso/foreword .html
This document was prepared by the Chemical Tests Commission of the International Union of Leather
Technologists and Chemists Societies (IUC Commission, IULTCS) in collaboration with the European
Committee for Standardization (CEN) Technical Committee CEN/TC 289, Leather, the secretariat of
which is held by UNI, in accordance with the agreement on technical cooperation between ISO and CEN
(Vienna Agreement).
It is based on IUC 11 published in J. Soc. Leather Tech. Chem., 49, pp. 25–29, 1965, and declared an official
method of the IULTCS in 1965.
IULTCS, originally formed in 1897, is a world-wide organization of professional leather societies to
further the advancement of leather science and technology. IULTCS has three Commissions, which
are responsible for establishing international methods for the sampling and testing of leather. ISO
recognizes IULTCS as an international standardizing body for the preparation of test methods for
leather.
This third edition cancels and replaces the second edition (ISO 4045:2008), which has been technically
revised as follows:
— change in title to include “and difference figure”;
— 5.1 and 6.1 have been revised;
— Clause 7 has been revised: two samples are only prepared when there is enough leather;
— 8.1 has been revised to more clearl
...

INTERNATIONAL STANDARD
Deleted: /FDIS
ISO 4045
IULTCS/IUC 11
Third edition
Deleted: 2017–11–22¶
2018-05
Leather — Chemical tests — Determination of pH and difference figure
Cuir — Essais chimiques — Détermination du pH et de l’indice de différence

IULTCS/IUC 11:2018(E)
Deleted: Copyright notice¶
This ISO document is a Draft International
Standard and is copyright‐protected by ISO.
Except as permitted under the applicable laws
of the user's country, neither this ISO draft nor
any extract from it may be reproduced, stored
in a retrieval system or transmitted in any
form or by any means, electronic,
photocopying, recording or otherwise, without
prior written permission being secured.¶
Requests for permission to reproduce should
be addressed to either ISO at the address
below or ISO's member body in the country of
the requester.¶
ISO copyright office¶
Case postale 56 • CH‐1211 Geneva 20¶
Tel. + 41 22 749 01 11¶
Fax + 41 22 749 09 47¶
E‐mail [e-mail]¶
Web www.iso.org¶
Reproduction may be subject to royalty
payments or a licensing agreement.¶
Violators may be prosecuted.¶
ii © ISO 2018 – All rights reserved

IULTCS/IUC 11:2018(E)
Contents Page
Foreword . iv
1  Scope . 1
2  Normative references . 1
3  Terms and definitions . 1
4  Principle . 1
5  Reagents . 2
6  Apparatus . 2
7  Sampling and preparation of the samples . 2
8  Procedure . 2
8.1  Preparation of the extract . 2
8.2  Calibration of the pH meter . 3
8.3  Determination of the pH value . 3
8.4  Determination of the difference figure . 3
9  Test report . 3

IULTCS/IUC 11:2018(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national
standards bodies (ISO member bodies). The work of preparing International Standards is normally
carried out through ISO technical committees. Each member body interested in a subject for which a
technical committee has been established has the right to be represented on that committee.
International organizations, governmental and non‐governmental, in liaison with ISO, also take part in
the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all
matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: www.iso.org/iso/foreword.html
This document was prepared by the Chemical Tests Commission of the International Union of Leather
Technologists and Chemists Societies (IUC Commission, IULTCS) in collaboration with the European
Committee for Standardization (CEN) Technical Committee CEN/TC 289, Leather, the secretariat of
which is held by UNI, in accordance with the agreement on technical cooperation between ISO and CEN Deleted: Agreement
(Vienna Agreement).
It is based on IUC 11 published in J. Soc. Leather Tech. Chem., 49, pp. 25–29, 1965, and declared an
official method of the IULTCS in 1965.
IULTCS, originally formed in 1897, is a world‐wide organization of professional leather societies to
further the advancement of leather science and technology. IULTCS has three Commissions, which are
responsible for establishing international methods for the sampling and testing of leather. ISO
recognizes IULTCS as an international standardizing body for the preparation of test methods for
leather.
This third edition cancels and replaces the second edition (ISO 4045:2008), which has been technically
revised as follows:
— change in title to include “and difference figure”;
— 5.1 and 6.1 have been revised;
— Clause 7 has been revised: two samples are only prepared when there is enough leather;
— 8.1 has been revised to more clearly explain the procedure;
iv © ISO 2018 – All rights reserved

IULTCS/IUC 11:2018(E)
— 8.2 has been added (previously part of the next clause);
— 8.3 and 8.4 (previously 8.2 and 8.3) have been revised a
...

NORME ISO
INTERNATIONALE 4045
IULTCS/IUC 11
Troisième édition
2018-05
Cuir — Essais chimiques —
Détermination du pH et de l'indice de
différence
Leather — Chemical tests —  Determination of pH and difference figure
Numéros de référence
IULTCS/IUC 11:2018(F)
©
ISO 2018
IULTCS/IUC 11:2018(F)
DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2018
Tous droits réservés. Sauf prescription différente ou nécessité dans le contexte de sa mise en oeuvre, aucune partie de cette
publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique,
y compris la photocopie, ou la diffusion sur l’internet ou sur un intranet, sans autorisation écrite préalable. Une autorisation peut
être demandée à l’ISO à l’adresse ci-après ou au comité membre de l’ISO dans le pays du demandeur.
ISO copyright office
Case postale 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Tél.: [phone]
Fax: [phone]
E-mail: [e-mail]
Web: www.iso.org
Publié en Suisse
ii © ISO 2018 – Tous droits réservés

IULTCS/IUC 11:2018(F)
Sommaire Page
Avant-propos .iv
1 Domaine d’application . 1
2 Références normatives . 1
3 Termes et définitions . 1
4 Principe . 1
5 Réactifs . 1
6 Appareillage . 2
7 Échantillonnage et préparation des échantillons . 2
8 Mode opératoire. 2
8.1 Préparation de l'extrait . 2
8.2 Étalonnage du pH-mètre . 3
8.3 Détermination du pH . 3
8.4 Détermination de l'indice de différence . 3
9 Rapport d'essai . 3
IULTCS/IUC 11:2018(F)
Avant-propos
L'ISO (Organisation internationale de normalisation) est une fédération mondiale d'organismes
nationaux de normalisation (comités membres de l'ISO). L'élaboration des Normes internationales est
en général confiée aux comités techniques de l'ISO. Chaque comité membre intéressé par une étude
a le droit de faire partie du comité technique créé à cet effet. Les organisations internationales,
gouvernementales et non gouvernementales, en liaison avec l'ISO participent également aux travaux.
L'ISO collabore étroitement avec la Commission électrotechnique internationale (IEC) en ce qui
concerne la normalisation électrotechnique.
Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont
décrites dans les Directives ISO/IEC, Partie 1. Il convient, en particulier de prendre note des différents
critères d'approbation requis pour les différents types de documents ISO. Le présent document a été
rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2 (voir www
.iso .org/directives).
L'attention est appelée sur le fait que certains des éléments du présent document peuvent faire l'objet de
droits de propriété intellectuelle ou de droits analogues. L'ISO ne saurait être tenue pour responsable
de ne pas avoir identifié de tels droits de propriété et averti de leur existence. Les détails concernant
les références aux droits de propriété intellectuelle ou autres droits analogues identifiés lors de
l'élaboration du document sont indiqués dans l'Introduction et/ou dans la liste des déclarations de
brevets reçues par l'ISO (voir www .iso .org/brevets).
Les appellations commerciales éventuellement mentionnées dans le présent document sont données
pour information, par souci de commodité, à l’intention des utilisateurs et ne sauraient constituer un
engagement.
Pour une explication de la nature volontaire des normes, la signification des termes et expressions
spécifiques de l'ISO liés à l'évaluation de la conformité, ou pour toute information au sujet de l'adhésion
de l'ISO aux principes de l’Organisation mondiale du commerce (OMC) concernant les obstacles
techniques au commerce (OTC), voir le lien suivant: www .iso .org/iso/fr/avant -propos .html
Le présent document a été élaboré par la Commission d'essais chimiques de l'Union internationale des
sociétés de techniciens et chimistes du cuir (commission IUC, IULTCS) en collaboration avec le comité
technique du Comité européen de normalisation (CEN) CEN/TC 289, Cuir, dont le secrétariat est tenu
par l'UNI, conformément à l'accord de coopération technique entre l'ISO et le CEN (Accord de Vienne).
Il est basé sur le document IUC 11, qui a été publié dans le J. Soc. Leather Tech. Chem., 49, pp. 25–29,
1965, et déclaré méthode officielle de l’IULTCS en 1965.
L'IULTCS est une organisation mondiale de sociétés professionnelles des industries du cuir fondée
en 1897 ayant pour mission de favoriser l'avancement des sciences et technologies du cuir. L’IULTCS
compte trois commissions, qui sont responsables de l’établissement de méthodes internationales
d’échantillonnage et d’essai des cuirs. L’ISO reconnaît l’IULTCS en tant qu’organisme international à
activités normatives pour l’élaboration de méthodes d’essai relatives au cuir.
Cette troisième édition annule et remplace la deuxième édition (ISO 4045:2008) qui a fait l’objet d’une
révision technique comme suit:
— modification du titre pour inclure «et de l'indice de différence»;
— les paragraphes 5.1 et 6.1 ont été révisés;
— l'Article 7 a été révisé: deux échantillons ne sont préparés que lorsqu'il y a assez de cuir;
— le paragraphe 8.1 a été révisé afin de mieux expliciter le mode opératoire;
— le paragraphe 8.2 a été ajouté (ancienne part
...