ISO 5603:2024

Rubber, vulcanized - Determination of adhesion to wire cord

This document specifies two methods for determining the adhesion strength of vulcanized rubber to wire cord which is embedded in the rubber. The two methods do not necessarily give the same results. They are applicable primarily to test pieces prepared in the laboratory under standard conditions and used for the development and control of materials and processes utilized in the manufacture of products reinforced with wire cord. NOTE The methods can also be used for single wire, for example bead wire. Method 1 reduces the dependence of the measured adhesion on the modulus and strength properties of the rubber.

Caoutchouc vulcanisé — Détermination de l'adhérence à un câble métallique

General Information

• Status: Published
• Publication Date: 08-Apr-2024
• ICS: 83.060 - Rubber
• Technical Committee: ISO/TC 45/SC 2 - Testing and analysis
• Drafting Committee: ISO/TC 45/SC 2 - Testing and analysis
• Current Stage: 6060 - International Standard published
• Start Date: 09-Apr-2024
• Due Date: 04-May-2025
• Completion Date: 09-Apr-2024

Relations

• Revises: ISO 5603:2017 - Rubber, vulcanized - Determination of adhesion to wire cord
• Effective Date: 06-May-2023

Overview

ISO 5603:2024 - Rubber, vulcanized - Determination of adhesion to wire cord specifies laboratory methods to measure the adhesion strength between vulcanized rubber and embedded wire cord. The standard defines two pull‑out test methods (Method 1 and Method 2), specimen preparation, required apparatus (moulds, vulcanizing press, tensile-testing machine), calibration and reporting. These methods are intended primarily for development and process control of materials and bonding systems used in wire‑reinforced rubber products and can also be applied to single wires (for example, bead wire).

Key topics and technical requirements

• Two test methods:
  • Method 1: Uses external reinforcement of the rubber block to reduce the influence of rubber modulus and strength on measured adhesion.
  • Method 2: No external reinforcement; a simpler configuration that can yield different results from Method 1.
• Test principle: Measure the force required to pull a single cord axially out of vulcanized rubber using a test jig with circular or square hole to ensure uniform stress distribution.
• Specimen preparation: Test pieces are prepared by vulcanizing cord and rubber together in purpose-designed moulds; detailed form, dimensions and preparation steps are specified.
• Materials: Recommendations for wire cord types (including typical brass‑plated steel constructions), storage (dry, desiccant), and unvulcanized rubber handling (fresh milling or solvent freshening).
• Apparatus & performance:
  • Vulcanizing press capable of at least 100 kN.
  • Tensile testing machine conforming to ISO 5893 (class 1) with jaw separation rate 50–150 mm/min.
  • Fixtures and mould designs for both methods are specified to ensure reproducibility.
• Calibration & quality control: Calibration schedules and references to ISO 18899 and ISO 23529 for equipment calibration and specimen conditioning.
• Results & reporting: Procedures for expression of results and test report content to support development, QC and supplier verification.

Applications and who uses it

ISO 5603:2024 is used for:

• Evaluating rubber-to-metal bonding and wire cord adhesion in tyres, pneumatic hoses, conveyor belts, rubber‑reinforced cables and other reinforced rubber goods.
• R&D and material development to compare bonding systems, adhesion promoters and compounding changes.
• Quality control and incoming inspection for cord suppliers and rubber product manufacturers.
• Test laboratories and certification bodies performing standardized pull‑out tests.

Typical users: materials scientists, test engineers, rubber compounders, tyre/hose manufacturers, QA/QC laboratories, and test-equipment suppliers.

Related standards

• ISO 2393 - Rubber test mixes - preparation and vulcanization procedures
• ISO 5893 - Tensile testing machine specification
• ISO 18899:2013 - Guide to calibration of test equipment
• ISO 23529 - Preparing and conditioning test pieces for physical test methods

Keywords: ISO 5603:2024, vulcanized rubber adhesion, wire cord adhesion test, pull‑out test, rubber‑to‑metal bonding, adhesion strength, tensile testing.

Standards Content (Sample)

International
Standard
ISO 5603
Fifth edition
Rubber, vulcanized — Determination
2024-04
of adhesion to wire cord
Caoutchouc vulcanisé — Détermination de l'adhérence à un câble
métallique
Reference number
© ISO 2024
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]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Materials . 2
6 Apparatus . 2
7 Calibration . 9
8 Test piece . 9
8.1 Form .9
8.2 Dimensions .11
8.3 Preparation .11
8.3.1 General .11
8.3.2 Method 1 .11
8.3.3 Method 2 . 12
8.3.4 Both methods . 12
9 Procedure .12
10 Expression of results . 14
11 Test report . 14
Annex A (normative) Calibration schedule .15

iii
Foreword
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bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
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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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
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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 www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee
SC 2, Testing and analysis.
This fifth edition cancels and replaces the fourth edition (ISO 5603:2017), which has been technically
revised.
The main changes are as follows:
— the normative references have been updated.
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
International Standard ISO 5603:2024(en)
Rubber, vulcanized — Determination of adhesion to wire cord
WARNING 1 — Persons using this document should be familiar with normal laboratory practice. This
document does not purport to address all of the safety problems, if any, associated with its use. It
is the responsibility of the user to establish appropriate safety and health practices and to ensure
compliance with any national regulatory conditions.
WARNING 2 — Certain procedures specified in this document might involve the use or generation of
substances, or the generation of waste, that could constitute a local environmental hazard. Reference
should be made to appropriate documentation on safe handling and disposal after use.
1 Scope
This document specifies two methods for determining the adhesion strength of vulcanized rubber to wire
cord which is embedded in the rubber.
The two methods do not necessarily give the same results.
They are applicable primarily to test pieces prepared in the laboratory under standard conditions and
used for the development and control of materials and processes utilized in the manufacture of products
reinforced with wire cord.
NOTE The methods can also be used for single wire, for example bead wire.
Method 1 reduces the dependence of the measured adhesion on the modulus and strength properties of
the rubber.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 2393, Rubber test mixes — Preparation, mixing and vulcanization — Equipment and procedures
ISO 5893, Rubber and plastics test equipment — Tensile, flexural and compression types (constant rate of
traverse) — Specification
ISO 18899:2013, Rubber — Guide to the calibration of test equipment
ISO 23529, Rubber — General procedures for preparing and conditioning test pieces for physical test methods
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/

4 Principle
The adhesion strength is determined by measuring the force required to pull out a single cord from the
surrounding rubber of a prepared test piece. The force is directed along the axis of the cord, using a test jig
containing a suitably chosen circular- or square-shaped hole to ensure uniformity of stress.
Test pieces of cord and rubber are prepared together by vulcanizing them under pressure.
In method 1, the exterior surface of the rubber is suitably reinforced.
In method 2, such reinforcement is not employed.
5 Materials
5.1 Wire cord, conforming to the specification of the bonding system to be investigated. If no specification
is given, brass-plated steel cord of construction (1 × 3 × 0,15) mm + (6 × 0,27) mm or of construction
(7 × 4 × 0,22) mm shall be used.
NOTE The sizes of the cords are defined here in terms of their diameter and the number of component wires,
starting from the centre core of the cord.
For quality control of cord, it shall be tested in the condition received, i.e. neither cleaned nor dried.
It is essential that the wire cord be stored in a dry atmosphere to prevent any surface deterioration. Storage
can conveniently be carried out in an airtight container which also contains a desiccating material (for
example, silica, SiO ). The container shall only be opened when removing wire cord and shall then be closed
immediately. It is also essential that the cord not be contaminated with dust from the desiccating material.
5.2 Unvulcanized rubber compound, conforming to the specification of the bonding system to be
investigated. Whenever possible, the rubber shall be freshly milled. If for any reason the rubber cannot be
remilled, the surface shall be freshened by wiping with a solvent and allowed to dry. The preferred solvent
is heptane, but a suitable alternative could be a petroleum solvent with a distillation range of about 65 °C to
125 °C; these solvents shall possess a maximum residue on evaporation of 3 mg per 100 cm of solvent. The
compound shall be stored at a standard laboratory temperature of (23 ± 2) °C or (27 ± 2) °C prior to use.
It can be in the form of a calendered sheet of suitable thickness and shall be protected by a dark-coloured
polyethylene film.
5.3 Reinforcement material, to stiffen the rubber block. This applies only to method 1. The reinforcement
can either be a sheet metal strip treated with adhesive promoter (when the thickness t is at least 0,5 mm)
or a strip of rigid rubberized steel cord fabric. A suitable fabric is one containing steel cords of high bending
stiffness, for example, one of construction (1 × 3 × 0,30) mm + (6 × 0,38) mm [when the thickness t is
(2,5 ± 0,1) mm maximum].
6 Apparatus
6.1 Mould, capable of producing a test piece in which a multiplicity of cords is embedded equally spaced
along its length. Different moulds are employed for the two methods.
a) Method 1
The mould is of a semi-follow-on type to obtain maximum consolidation of rubber around the cord during
the pressing stage, but thereafter becomes a fixed-cavity mould.
One suitable mould designed to accommodate steel cord fabric reinforcement is shown in Figure 1. This
mould produces test pieces of length 310 mm containing 21 cords, but similar moulds employing other
numbers of cords greater than nine are acceptable. The mould dimension x will depend on the embedded
length of test piece required (which is governed by the diameter of wire cord used, see 8.2). The mould shall

be provided with pairs of inserts or spacers to obtain the different lengths of cord embedment. Dimension y
is sufficiently great to allow the incorporation of excess rubber during moulding (see 8.3.1).
Another suitable mould designed to accommodate steel strip reinforcement is shown in Figure 2. A
tensioning device for the cords can be used with this mould. Figure 3 details some mould dimensions and
describes the exchangeable steel spacers which are required for different cord sizes for the moulds shown in
Figures 1 and 2.
Any mould producing test pieces of the correct dimensions and applying the moulding force directly on to
the rubber, for example by use of a suitable spring, is also acceptable.
If desired, the moulds can impart suitable features on to the moulded test piece to facilitate cord centring
during subsequent testing.
Key
1 extraction tool 5 pair of steel spacers
2 semi-follow-on lid 6 bottom spacers
3 ram 7 steel cord
4 top spacers
Figure 1 — Layout of one type of semi-follow-on mould and its extraction tools for method 1

Dimensions in millimetres
Key
1 metal reinforcement sheets (thickness t)
2 upper ledge/spacer
3 cover plate
4 centring bolts
5 tensioning frame
6 extraction tool
7 lower edge
a
Detail of cross-section of slot (for dimension a, see Figure 3).
Figure 2 — Layout of a second type of semi-follow-on mould and its extraction tool for method 1
Dimensions in millimetres
a) Spacers for the mould in Figure 1

b) Exchange ledges/spacers for the mould in Figure 2
Cord diameter Details of ledge chosen
d a b c e
≥ 0,5 but < 0,7
...