EN ISO 7854:1997

Rubber- or plastics-coated fabrics - Determination of resistance to damage by flexing (ISO 7854:1995)

Describes the De Mattia method, Schildknecht method and crumple/flex method for the assessment of the resistance of coated fabrics to damage by repeated flexing. Cancels and replaces the first edition, which has been technically revised.

Mit Kautschuk oder Kunststoff beschichtete Textilien - Bestimmung der Beständigkeit gegen Beschädigung durch Biegen (ISO 7854:1995)

Diese Internationale Norm beschreibt drei Verfahren für die Bewertung der Beständigkeit beschichteter Textilien gegen Schädigung durch wiederholte Biegebeanspruchung.

Supports textiles revêtus de caoutchouc ou de plastique - Détermination de la résistance à la flexion (ISO 7854:1995)

La présente Norme internationale prescrit trois méthodes pour la détermination de la résistance des supports textiles revêtus à un endommagement par flexions répétées.

Gumirane ali plastificirane tekstilije - Ugotavljanje odpornosti proti poškodbam zaradi upogibanja (ISO 7854:1995)

General Information

• Status: Published
• Publication Date: 18-Mar-1997
• Withdrawal Date: 29-Sep-1997
• ICS: 83.140 - Rubber and plastics products
• Technical Committee: CEN/TC 248 - Textiles and textile products
• Drafting Committee: CEN/TC 248/WG 4 - Coated fabrics
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 14-Jun-2006
• Completion Date: 14-Jun-2006
• Ref Project: SIST EN ISO 7854:1999 - Rubber- or plastics-coated fabrics - Determination of resistance to damage by flexing (ISO 7854:1995)

Overview

EN ISO 7854:1997 (ISO 7854:1995) specifies laboratory methods to determine the resistance of rubber- or plastics-coated fabrics to damage by repeated flexing. It replaces the first edition and standardizes three established flex-fatigue tests - De Mattia (Method A), Schildknecht (Method B) and the crumple/flex (Method C) - including sample preparation, apparatus criteria, test procedures, inspection and reporting. The standard emphasizes repeatability, conditioning atmospheres and limits of correlation between methods.

Key topics and technical requirements

• Three test methods
  • Method A (De Mattia): Small folded strip flexed at high speed; suitable when material cannot be mounted for other methods or sample size is limited.
  • Method B (Schildknecht): Test strip mounted around opposing cylinders that reciprocate to compress/relax the cylinder; suitable for light to medium-duty coated fabrics.
  • Method C (Crumple/flex): Large cylindrical specimen mounted between flanged discs with combined twisting and compression; suited for severe flexing conditions and allows post-flex tests (e.g., hydrostatic head).
• Apparatus and parameters: The standard defines specific machine characteristics (e.g., frequencies, stroke lengths and geometry), clip/mounting details and test-piece dimensions for each method to improve reproducibility.
• Sample preparation and selection: Specifies the number, orientation (longitudinal/transverse), sizes and location across roll width to reduce variability.
• Conditioning and atmosphere: Tests must be conducted in specified standard atmospheres (ISO 2231 types A/B/C) and care must be taken to control air temperature and ventilation to avoid micro-climate or thermal artefacts.
• Examination and reporting: Guidance on inspection intervals, criteria for termination (number of cycles or observed damage), assessment of severity and mandatory test report items (method reference, identification, cycles to failure, damage severity, deviations).

Practical applications

• Assessing flex-fatigue durability of coated fabrics used in outdoor clothing, inflatable products, industrial covers, tarpaulins, conveyor belts and protective equipment.
• Selecting or validating coatings and substrate combinations for service life under repeated bending.
• Supporting product specifications, quality control, and comparative evaluations for R&D and manufacturing.

Who uses this standard

• Textile and rubber test laboratories, product designers, materials engineers, quality managers, and manufacturers of coated fabrics and coated textile products.

Related standards

• ISO 132 (De Mattia apparatus), ISO 1420 (hydrostatic-head), ISO 2231 (conditioning atmospheres), ISO 2286 (roll characteristics), ISO 8096-3 (apparatus illustrations for coated fabrics).

Keywords: EN ISO 7854:1997, ISO 7854:1995, rubber- or plastics-coated fabrics, flexing resistance, De Mattia, Schildknecht, crumple/flex, coated fabrics durability testing, flex fatigue.

Standards Content (Sample)

SLOVENSKI STANDARD
01-marec-1999
Gumirane ali plastificirane tekstilije - Ugotavljanje odpornosti proti poškodbam
zaradi upogibanja (ISO 7854:1995)
Rubber- or plastics-coated fabrics - Determination of resistance to damage by flexing
(ISO 7854:1995)
Mit Kautschuk oder Kunststoff beschichtete Textilien - Bestimmung der Beständigkeit
gegen Beschädigung durch Biegen (ISO 7854:1995)
Supports textiles revetus de caoutchouc ou de plastique - Détermination de la résistance
a la flexion (ISO 7854:1995)
Ta slovenski standard je istoveten z: EN ISO 7854:1997
ICS:
59.080.40 3RYUãLQVNRSUHYOHþHQH Coated fabrics
WHNVWLOLMH
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL ISO
STANDARD 7854
Second edition
1995-08-15
Rubber- or plastics-coated fabrics -
Determination of resistance to darnage
by flexing
Supports textiles rev6tus de caoutchouc ou de plastique - Determination
de Ia rdsistance 2 Ia flexion
Reference number
ISO 7854:1995(E)
ISO 7854:1995(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. Esch 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
(1 EC) on all matters of electrotechnical standardization.
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.
International Standard ISO 7854 was prepared by Technical Committee
ISOJTC 45, Rubber and rubber products.
This second edition cancels and replaces the first edition (ISO 7854:
1984), which has been technically revised.
Annex A of this International Standard is for information only.
0 ISO 1995
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronie or mechanical, including photocopying and
mrcrofilm, without permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-l 211 Geneve 20 l Swi tzerlan d
Printed in Switzerland
0 ISO
ISO 7854: 1995(E)
Introduction
Investigation of dynamic-flex fatigue properties of coated fabrics has for
a number of years suffered from poor repeatability (due in part to the un-
known but inevitable variability of the material tested) and worse
reproducibility. Nevertheless, dynamic-flex performante of coated fabrics
has been long and widely used as a measure of the product quality.
The methods traditionally used suffered from the common deficiency of
testing only a small test piece. The De Mattia test is unsuitable for ma-
terials that exhibit “Set ”, such as thermoplastics, and the Schildknecht
method has disadvantages when testing the heavier industrial fabrics and
also tends to require very high geometric ratios and consequently time-
consuming tests to verify results. In addition, the mounting of
Schildknecht test pieces tan seriously affect test results and repeatability.
Both the De Mattia and Schildknecht methods are also uni-directional,
which in some cases is advantageous, but in many cases is not appropri-
ate, e.g. where bi-directional Stresses are exerted during use.
This revised edition of ISO 7854 attempts to standardize the mounting
difficulties associated with the Schildknecht apparatus (method B) and in-
troduces a bi-directional flex fatigue test that provides a large test piece,
enabling post-flexing investigations, such as hydrostatic-head tests, to be
conducted. The apparatus is described in ISO 8096-3:1988, Rubber- or
plas tics-cos ted fabrics for wa ter-resis tan t clo thing - Specifica tion -
fabrics. The apparatus
Part 3: Natura/ rubber- and synthetic rubber-coated
outlined there in illustrative form (see the note to F.l in annex F of
ISO 8096-3:1988) has been developed in more detail and is now widely
available commercially from a number of sources.
Flex testing tan provide a useful indication of the durability of coated fab-
ries. However, for most applications, flexing conditions induced by these
test methods are dissimilar to the conditions met in practice. In particular,
the micro-climate induced around the test piece and the thermal Stresses
induced in the molecular structure of the coating during flexing are unlikely
to be representative of practical situations. lt is important therefore that
these effects be kept to a minimum and their effect be given due con-
sideration when test results are being considered. Consequently, it is im-
portant to ensure that the air temperature around the test pieces is kept
constant during the test. This tan be achieved either by maintaining ade-
quate non-forced, open Ventilation around the test pieces or by controlling
the air temperature within any closed Container in which the test apparatus
may be mounted.
Three methods are described. Method A (De Mattia) may be found suit-
able for flex testing coated fabrics which cannot be constrained into the
configuration required by method B or where the amount of material
available for testing is too small to permit the other methods to be em-
ployed. Method B (Schildknecht) will be found useful for flex testing
coated fabrics of relatively lightweight construction or whose practical

0 ISO
ISO 7854: 1995(E)
usage would be in the light to medium range in terms of severity of
flexing.
Method C (crumple/flex test) has been found useful in testing coated
fabrics which will be subject to severe usage in terms of their flexing ca-
pability under arduous conditions. The method requires a large test piece
but this provides certain advantages for selecting test pieces for related
testing after flexing, e.g. hydrostatic-head testing.
Some coated ion when f lexed in
fabrics are more susceptible to delaminat
given in annex A .
the wet state and attent on IS drawn to the information
Because of the differentes in the nature of the flexing in the three
methods, no true correlation of results between the different methods is
possible.
iv
INTERNATIONAL STANDARD 0 ISO ISO 7854:1995(E)
- Determination
Rubber- or plastics-coated fabrics
of resistance to darnage by flexing
tween a pair of flat grips, one of which reciprocates,
1 Scope
causing the folded test piece to be bent outwards five
times per second. This high-speed folding of the test
This International Standard describes three methods
piece is continued for either a pre-set number of cy-
of assessing the resistance of coated fabrics to dam-
cles or until darnage to the test piece is apparent.
age by repeated flexing.
3.2 Apparatus
2 Normative references
The following Standards contain provisions which,
3.21 Flex-testing machine, as specified in
through reference in this text, constitute provisions
ISO 132, with pairs of flat grips. One of the grips of
of this lnternational Standard. At the time of publi-
each pair is capable of a reciprocating motion in a
cation, the editions indicated were valid. All Standards
vertical plane with a stroke length of (57 +it5) mm and
are subject to revision, and Parties to agreements
a frequency of 5,0 Hz + 0,2 Hz.
-
based on this International Standard are encouraged
Esch pair of grips is positioned so that they are
to investigate the possibility of applying the most re-
70 mm + 1 mm apart when in the open Position and
cent editions of the Standards indicated below. -
13 mm + 0,5 mm apart when in the closed Position.
Members of IEC and ISO maintain registers of cur- -
rently valid International Standards.
ISO 132: 1983, Rubber, vulcanized - Determination
3.3 Preparation of test pieces
of flex cracking (De Mattia).
Select six test pieces each 37,5 mm + 1 mm wide x
ISO 1420:1987, Rubber- or plastics-coated fabrics -
125 mm long from the usable width G the roll as de-
Determination of resis tance to pene tra tion by water.
fined in ISO 2286. Three test pieces shall be selected
with their longer dimension in the longitudinal direc-
ISO 2231: 1989, Rubber- or plastics-coated fabrics -
tion of the roll of coated fabric and three test pieces
Standard a tmospheres for conditioning and testing.
with the longer dimension in the transverse direction
of the roll of coated fabric. Test pieces shall be se-
ISO 2286: 1986, Rubber- or plastics-coated fabrics -
lected from positions evenly spaced across the full
Determination of roll charac teris tics.
width and length of the Sample.
NOTES
- De Mattia method
3 Method A
1 In the case of woven-fabric Substrates, as far as possible
no two test pieces should contain the same threads of the
3.1 Principle
fabric in the direction to be tested.
A rectangular Strip of coatedfabric is folded twice so
2 Together with suitable increases in the width of grips,
that its long edges meet forming a Strip measuring
the test piece size may be increased so as to permit sub-
125 mm x 12,5 mm. This folded Strip is mounted be- sequent hydrostatic-head tests to be conducted.
ISO 7854: 1995(E)
0 ISO
or breakdown of the coated fabric is to be deter-
3.4 Conditioning and testing atmosphere
mined, stop the apparatus at predetermined intervals
Condition the test pieces in atmosphere A, B or C of
to allow examination sf the test piece.
ISO 22319989, and conduct the test in that atmos-
phere.
3.6 Examination of test pieces
3.5 Procedure
Examine the test pieces initially whilst retained in the
Fold each test piece twice as illustrated in figure 1,
grips of the flexing apparatus or, if required, remove
with the coating to be tested outermost, along lines
the test pieces from the grips for a more detailed in-
12,5 mm from each of the longer edges and to a
spection in accordance with clause 6. Test pieces re-
width of 12,5 mm. Mount each folded test piece be-
moved from the grips shall not be remounted.
tween a pair of grips whilst they are in the open pos-
ition so that the test piece is slightly taut and so that
Terminate flexing either at the specified number of
the coating on the centre section of the test piece
cycles or at the first inspection at which test pieces
will be subjected to an outward fold. Move the grips
show signs of deterioration or cracking of the type
together by hand and guide each test piece into a fold
under investigation. Where relevant, record at each
at approximately the midpoint (see figure 1).
examination the total number of flexes to which the
Set the apparatus in motion and stop it after the test pieces have been subjected and assess the flex-
specified number of cycles or, if the Point of failure ing darnage in accordance with clause 6.
Fold 1
____------------------------------------------------------------------------------
Fold 2
----------------------------------------------------------------------------------
All folded plies to
remain in contact
Figure 1 - Illustration of folding and configuration of test piece for De Mattia method

0 ISO
ISO 7854:1995(E)
ISO 2286. Three test pieces shall be selected with
3.7 Test report
their longer dimension in the longitudinal direction of
the roll of coated fabric and three test pieces with
The test report shall include the following particulars:
their longer dimension in the transverse direction of
a reference to this method of test, i.e. Method A
a)
the roll of coated fabric. Test pieces shall be selected
of ISO 785411995;
from positions evenly spaced across the full width and
length of the Sample.
b) all details necessary for the identification of the
coated fabric, including any relevant reference NOTE 3 In the case of woven-fabric Substrates, as far as
possible no two test pieces should contain the same
number;
threads of the fabric in the direction to be tested.
the specified number of flexes for which the test
c)
4.3.2 Test pieces for subsequent
was run and at which the examination was made
hydrostatic-head testing
and/or the number of flexes at final inspection;
When hydrostatic-head tests are to be subsequently
the severity of darnage at each inspection, re-
d)
conducted in accordance with
method B of
ported in accordance with clause 6;
ISO 1420:1987, the test piece size used for flexing
e) details of any deviation from the Standard test shall be 105 mm x 65 mm and the test piece for
procedure. hydrostatic-head testing shall be taken from the cen-
tral Portion of the flexed test piece.
4.4 Conditioning and testing atmosphere
4 Method B - Schildknecht method
Condition the test pieces in atmosphere A, B or C of
4.1 Principle
ISO 2231:1989, and conduct the test in t
...