ISO 4646:2022

INTERNATIONAL ISO
STANDARD 4646
Third edition
2022-08
Rubber- or plastics-coated fabrics —
Low-temperature impact test
Supports textiles revêtus de caoutchouc ou de plastique — Essai de
choc à basse température
Reference number
ISO 4646:2022(E)
© ISO 2022

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ISO 4646:2022(E)
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© ISO 2022
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ISO 4646:2022(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Apparatus and materials .1
5 Test pieces .3
6 Time – interval between manufacturing and testing . 3
7 Conditioning of test pieces .4
8 Procedure .4
9 Test report . 4
Annex A (informative) Speed calibration of a solenoid-actuated low-temperature impact
tester . 6
Bibliography . 9
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ISO 4646:2022(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
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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
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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).
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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 4, Products (other than hoses).
This third edition cancels and replaces the second edition (ISO 4646:1989), which has been technically
revised.
The main changes are as follows:
— Clause 3, "Terms and definitions", has been added, and the subsequent clauses have been renumbered;
— in 4.1, another type of impact tester which is generally used in the industries has been added in
Figure 1 as b);
— in 4.3, Dichlorodifuloromethane has been replaced with methylcyclohexane due to its toxicity, and
other heat-transfer mediums have also 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.
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INTERNATIONAL STANDARD ISO 4646:2022(E)
Rubber- or plastics-coated fabrics — Low-temperature
impact test
WARNING — 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.
1 Scope
This document specifies a procedure for determining the lowest temperature at which rubber- or
plastics-coated fabrics will not exhibit fractures or coating cracks when subjected to specific impact
conditions.
Rubber-or plastics-coated fabrics are used in many applications involving low-temperature flexing
with or without impact. Data obtained by this method can be used to predict the behaviour of these
coated fabrics at low temperatures only in the applications in which the conditions of deformation are
similar to those specified in the method.
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 2231, Rubber- or plastics-coated fabrics — Standard atmospheres for conditioning and testing
ISO 2286-3, Rubber- or plastics-coated fabrics — Determination of roll characteristics — Part 3: Method
for determination of thickness
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 Apparatus and materials
Typical two types of impact testers which are generally used in the industries are shown in Figure 1 a)
and b). Some other testers can be commercially available, however, the apparatus used shall meet the
requirements specified below for certain components.
4.1 Test piece clamps and striking arm, it shall be designed to hold the test piece(s) as cantilever
beam(s). Each individual test piece shall be held firmly and securely in the clamp without causing
distortion to the test piece.
The striking edge shall move relative to the test piece(s) along a trajectory normal to the upper surface
of the test piece(s) at a linear testing speed of 1,8 m/s to 2,1 m/s at impact and during at least the
following 6 mm of travel after impact. In order to maintain this velocity consistently within the heat-
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ISO 4646:2022(E)
transfer medium (4.3), the striking arm shall be positively driven. It may be necessary in some cases to
reduce the number of test pieces tested at one time.
The striking edge shall have a radius of 1,6 mm ± 0,1 mm;
The striking arm and the test piece clamps shall have a clearance at and immediately following impact
in accordance with the dimensions listed in Table 1.
Dimensions in millimetres
a) Straight-line motion b) Rotational motion
Key
1 test piece
2 striker
3 test piece clamp
4 locus described by point on striker closest to test piece clamp
5 locus described by impact point on striker
a
See Table 1.
Figure 1 — Test piece clamps and striking arm
4.2 Insulated tank
4.3 Heat-transfer medium, liquid or gaseous, which remains fluid at the test temperature and which
does not appreciably affect the material being tested shall be used.
CAUTION — Where a flammable or toxic solvent is used as the heat-transfer medium, the
customary precautions in handling such a material shall be exercised.
a) for temperatures down to −60 °C, silicone fluids are usually suitable owing to their chemical
inertness towards rubbers, their non-flammability and their non-toxicity;
2
NOTE A kinematic viscosity of about 5 mm /s at ambient temperature has been found suitable.
b) for temperatures down to −73 °C, ethanol;
c) for temperatures down to −120 °C, methylcyclohexane cooled by liquid nitrogen (found to be
satisfactory with the use of suitable apparatus).
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ISO 4646:2022(E)
4.4 Stirrer, to provide thorough circulation of the heat-transfer medium.
4.5 Temperature control, automatic or manual, for controlling the temperature of the heat-transfer
medium to within ±0,5 °C of the desired temperature.
Powdered solid carbon dioxide (dry ice), liquid nitrogen or liquid carbon dioxide are recommended for
lowering the temperature. An electric immersion heater is required for raising the temperature.
4.6 Thermocouple, with associated temperature indicator graduated in 1 °C divisions and having a
range suitable for the temperature at which the tests are to be made.
The thermocouple shall be constructed of copper-constantan wire between 0,2 mm and 0,5 mm in
diameter and shall be fusion-bonded at the juncti
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