ISO 34-1:2022

INTERNATIONAL ISO
STANDARD 34-1
Fifth edition
2022-06
Rubber, vulcanized or
thermoplastic — Determination of
tear strength —
Part 1:
Trouser, angle and crescent test pieces
Caoutchouc vulcanisé ou thermoplastique — Détermination de la
résistance au déchirement —
Partie 1: Éprouvettes pantalon, angulaire et croissant
Reference number
© ISO 2022
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ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Principle . 2
4.1 General . 2
4.2 Method A: Method to determine trouser tear strength . 2
4.3 Method B, procedure (a): Method to determine unnicked angle tear strength. 3
4.4 Method B, procedure (b): Method to determine nicked angle tear strength . 3
4.5 Method C: Method to determine crescent tear strength . 3
5 Apparatus . 3
5.1 Dies . 3
5.2 Nick cutter . 5
5.3 Thickness gauge . 6
5.4 Testing machine . . 6
5.5 Grips . 6
6 Calibration .6
7 Test piece . 7
8 Number of test pieces .7
9 Temperature of test . 7
10 Procedure .8
11 Expression of results . 8
12 Precision . 8
13 Test report . 8
Annex A (informative) Precision results from an interlaboratory test programme .10
Annex B (normative) Calibration schedule . .13
Bibliography .15
iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
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electrotechnical standardization.
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described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
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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 34-1:2015), which has been technically
revised.
The main changes are as follows:
— the detailed information regarding the methods in Clause 1 have been moved to Clause 4;
— Figure 4 in 5.5 has been revised;
— expressions in Clauses 7 and 11 have been modified to avoid unexpected misunderstandings and to
get precise results.
A list of all parts in the ISO 34 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
INTERNATIONAL STANDARD ISO 34-1:2022(E)
Rubber, vulcanized or thermoplastic — Determination of
tear strength —
Part 1:
Trouser, angle and crescent test pieces
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
determine the applicability of any other restrictions.
WARNING 2 — Certain procedures specified in this document can 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 three test methods for the determination of the tear strength of vulcanized or
thermoplastic rubber, namely the following:
— method A, using a trouser test piece;
— method B, using an angle test piece, with or without a nick of specified depth;
— method C, using a crescent test piece with a nick.
The value of tear strength obtained depends on the shape of the test piece, speed of stretching, and
temperature of test. It can also be susceptible to grain effects in rubber.
NOTE A separate method for the determination of the tear strength of small test pieces of rubber (Delft test
pieces) is specified in ISO 34-2.
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 1382, Rubber — Vocabulary
ISO 5893, Rubber and plastics test equipment — Tensile, flexural and compression types (constant rate of
traverse) — Specification
ISO 6133, Rubber and plastics — Analysis of multi-peak traces obtained in determinations of tear strength
and adhesion strength
ISO 18899:2013, Rubber — Guide to the calibration of test equipment
ISO 23529:2016, Rubber — General procedures for preparing and conditioning test pieces for physical test
methods
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1382 and the following apply.
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/
3.1
trouser tear strength
median force required to propagate a cut in a specified trouser-shaped test piece by tearing, divided by
the thickness of the test piece, the force acting in a direction substantially in the plane of the cut
Note 1 to entry: The median force is calculated in accordance with ISO 6133.
3.2
unnicked angle tear strength
maximum force required to rupture a specified angle-shaped test piece, divided by the thickness of the
test piece, the force acting in a direction substantially along the length of the test piece
3.3
nicked angle tear strength
maximum force required to cause a nick cut in a specified angle-shaped test piece to extend by tearing
of the rubber, divided by the thickness of the test piece, the force acting in a direction substantially
normal to the plane of the nick
3.4
crescent tear strength
maximum force required to cause a nick cut in a specified crescent-shaped test piece to extend by tearing
of the rubber, divided by the thickness of the test piece, the force acting in a direction substantially
normal to the plane of the nick
4 Principle
4.1 General
The test consists in measuring the force required to tear a specified test piece, in continuation of the cut
or nick already produced in the test piece or, in the case of method B, procedure (a), completely across
the width of the test piece.
The tearing force is applied by means of a tensile testing machine, operated without interruption at
a constant rate of traverse until the test piece breaks. Dependent upon the method employed, the
maximum or median force achieved is used to calculate the tear strength.
No correlation between data obtained by the alternative test pieces is implied.
4.2 Method A: Method to determine trouser tear strength
Method A, using the trouser test piece, is preferred because it is not sensitive to the length of the cut,
unlike the other two test pieces in which the nick has to be very closely controlled. In addition, the
results obtained are more easily related to the fundamental tear properties of the material and are less
sensitive to modulus effects (provided that the leg extension is negligible) and the rate of propagation
of the tear is directly related to the rate of grip separation. With some rubbers, the propagation of tear
[3]
is not smooth (knotty tear), and analysis of results can be difficult .
4.3 Method B, procedure (a): Method to determine unnicked angle tear strength
This test is a combination of tear initiation and propagation. Stress is built up at the point of the angle
until it is sufficient to initiate a tear and then further s
...