ISO 4604:2011

INTERNATIONAL ISO
STANDARD 4604
Second edition
2011-11-15
Reinforcement fabrics — Determination
of conventional flexural stiffness —
Fixed-angle flexometer method
Tissus de renforcement — Détermination de la rigidité conventionnelle
en flexion — Méthode du flexomètre à angle fixe
Reference number
ISO 4604:2011(E)
©
ISO 2011

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ISO 4604:2011(E)
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ISO 4604:2011(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 4604 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 13, Composites and
reinforcement fibres.
This second edition cancels and replaces the first edition (ISO 4604:1978), of which it constitutes a minor
revision. The main changes are as follows:
— the scope has been broadened to cover all reinforcement fabrics (not just textile glass fabrics) and the title
of the standard modified in consequence;
— the normative references clause has been updated.
© ISO 2011 – All rights reserved iii

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INTERNATIONAL STANDARD ISO 4604:2011(E)
Reinforcement fabrics — Determination of conventional flexural
stiffness — Fixed-angle flexometer method
1 Scope
This International Standard specifies a method of determining the conventional flexural stiffness of reinforcement
fabrics by means of a fixed-angle flexometer. This method is not suitable for testing fabrics that are limp or that
have a marked tendency to curl or twist or fray.
2 Normative references
The following referenced documents are indispensable for the application 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 291, Plastics — Standard atmospheres for conditioning and testing
ISO 3374, Reinforcement products — Mats and fabrics — Determination of mass per unit area
3 Principle
A rectangular strip of fabric is supported on a horizontal platform in a direction perpendicular to one edge of
the platform. The strip is moved in the direction of its length so that an increasing portion overhangs and bends
down under its own weight. When the tip of the specimen has reached a plane passing through the edge of the
platform and inclined at an angle of 41,5° below the horizontal, the overhanging length is measured.
The conventional flexural stiffness is calculated from the overhanging length of the test specimen and the mass
per unit area of the fabric.
NOTE This determination of the conventional flexural stiffness is based on a report published in Shirley lnstitute
Memoirs, 9 (1930), p. 81, and Journal of the Textile lnstitute, 21 (1930), T380.
4 Apparatus
4.1 Fixed-angle flexometer, the essential features of which are shown in Figure 1.
On the horizontal platform P rests a slide S, graduated on its upper surface in millimetres.
The under-surface of S is covered with a layer of high-friction antistatic material such as sheet rubber, and the
upper surface of P is polished so that, when S is moved, it will carry forward a specimen placed between the
slide and the platform P.
The width of the slide S shall be 25 mm and the length at least 300 mm, and its mass shall be 10 g ± 2 g per
centimetre of length.
When the front edge of the slide coincides with the front edge of P, the zero of the scale on S coincides with
a datum line D on the ins
...