Paints and varnishes - Determination of flow time by use of flow cups (ISO 2431:2011)

This International Standard specifies a method for determining the flow time of paints, varnishes and related products that can be used to control consistency. Four flow cups of similar dimensions, but having orifice diameters of 3 mm, 4 mm, 5 mm and 6 mm, are specified. Two methods for checking the flow cups for wear and tear are given (see Annex A). Flow cups with a replaceable jet are not covered by this International Standard as the close tolerances on the supply of the material under test to the jet are not met. Commonly used dipping flow cups are also not covered by this International Standard. In general, the fabrication tolerances for such flow cups are greater than those of the flow cups specified in this International Standard. Therefore flow time determinations with dipping flow cups give a precision which is lower than that obtained with the flow cups specified in this International Standard (see Clause 9). The method is limited to testing materials for which the breakpoint of the flow from the orifice of the flow cup can be determined with certainty. This point is difficult to determine and reproduce for materials with flow times near the upper limit of the measurement range (100 s) due to slowing-down effects.

Beschichtungsstoffe - Bestimmung der Auslaufzeit mit Auslaufbechern (ISO 2431:2011)

1.1 Diese Internationale Norm beschreibt ein Verfahren zum Bestimmen der Auslaufzeit von Beschichtungsstoffen und ähnlichen Produkten, das zum Prüfen der Konsistenz angewendet werden kann. Ein Verfahren zum Einstellen auf die richtige Verarbeitungskonsistenz bei der Verarbeitungstemperatur wird im Anhang A beschrieben.
1.2 Es werden 4 Auslaufbecher mit ähnlichen Maßen, jedoch mit unterschiedlichen Düsendurchmessern von 3 mm, 4 mm, 5 mm und 6 mm festgelegt. Das Verfahren zu ihrer Kalibrierung wird angegeben.
1.3 Das Verfahren ist auf die Prüfung von Stoffen, bei denen das Abreißen des aus der Düse des Auslaufbechers fließenden Flüssigkeitsfadens eindeutig festgestellt werden kann, begrenzt. Das Abreißen ist bei Stoffen mit Auslaufzeiten über 100 s wegen des langsamer werdenden Fließens schwierig festzustellen und zu reproduzieren.

Peintures et vernis - Détermination du temps d'écoulement au moyen de coupes d'écoulement (ISO 2431:2011)

L'ISO 2431:2011 spécifie une méthode de détermination du temps d'écoulement des peintures, vernis et produits assimilés, utilisable pour contrôler leur consistance.
Quatre coupes d'écoulement de dimensions semblables mais ayant des orifices de 3 mm, 4 mm, 5 mm et 6 mm de diamètres sont spécifiées. Deux méthodes permettant de vérifier l'usure et la détérioration des coupes d'écoulement sont données dans une annexe.
Les coupes d'écoulement à ajutage ajustable ne sont pas couvertes par l'ISO 2431:2011 en raison du fait que les tolérances étroites relatives à l'alimentation en matériau soumis à essai de l'ajutage ne sont pas respectées.
Les coupes d'écoulement par plongée couramment utilisées ne sont également pas couvertes par l'ISO 2431:2011. En général, les tolérances de fabrication de telles coupes d'écoulement sont supérieures à celles des coupes d'écoulement spécifiées dans l'ISO 2431:2011. Par conséquent, les déterminations de temps d'écoulement effectuées avec des coupes d'écoulement par plongée donnent une fidélité inférieure à celle obtenue avec les coupes d'écoulement spécifiées dans l'ISO 2431:2011.
La méthode est limitée aux essais sur des matériaux dont il est possible de déterminer avec certitude le point de rupture de l'écoulement à l'orifice de la coupe. Ce point de rupture est difficile à déterminer et à reproduire pour les matériaux dont le temps d'écoulement est proche de la limite supérieure de la plage de mesurage (100 s), en raison d'effets de ralentissement.

Barve in laki - Ugotavljanje iztočnega časa z uporabo iztočnih čaš (ISO 2431:2011)

Ta mednarodni standard določa metodo za ugotavljanje iztočnega časa barv, lakov in povezanih izdelkov, ki jo je mogoče uporabljati za nadzor konsistence. Določene so štiri iztočne čaše podobnih mer s premeri odprtin 3 mm, 4 mm, 5 mm in 6 mm. Opisani sta dve metodi za preverjanje obrabljenosti iztočnih čaš (glejte dodatek A). Ta mednarodni standard ne zajema iztočnih čaš z zamenljivo šobo, ker ozke tolerance za dovod preskušanega materiala v šobo niso dosežene. Prav tako ta mednarodni standard ne zajema pogosto uporabljenih potopnih iztočnih čaš. Na splošno so proizvodne tolerance za take iztočne čaše večje od toleranc iztočnih čaš iz tega mednarodnega standarda. Zato je ugotavljanje iztočnega časa s potopnimi iztočnimi čašami manj natančno od preskusov z iztočnimi čašami iz tega mednarodnega standarda (glejte točko 9). Metoda je omejena na preskušanje materialov, za katere je mogoče prekinitveno točko iztoka iz odprtine iztočne čaše natančno določiti. Za materiale z iztočnim časom blizu zgornje mejne vrednosti razpona merjenja (100 s) je to točko težko določiti, saj se rezultati zaradi upočasnjevanja običajno razlikujejo med ponovitvami.

General Information

Status
Withdrawn
Public Enquiry End Date
24-Sep-2010
Publication Date
06-Dec-2011
Withdrawal Date
06-Aug-2019
Technical Committee
Current Stage
9900 - Withdrawal (Adopted Project)
Start Date
24-Jul-2019
Due Date
16-Aug-2019
Completion Date
07-Aug-2019

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SLOVENSKI STANDARD
SIST EN ISO 2431:2012
01-februar-2012
1DGRPHãþD
SIST EN ISO 2431:1997
SIST EN ISO 2431:1997/AC:2002
%DUYHLQODNL8JRWDYOMDQMHL]WRþQHJDþDVD]XSRUDERL]WRþQLKþDã ,62
Paints and varnishes - Determination of flow time by use of flow cups (ISO 2431:2011)
Beschichtungsstoffe - Bestimmung der Auslaufzeit mit Auslaufbechern (ISO 2431:2011)
Peintures et vernis - Détermination du temps d'écoulement au moyen de coupes
d'écoulement (ISO 2431:2011)
Ta slovenski standard je istoveten z: EN ISO 2431:2011
ICS:
87.040 Barve in laki Paints and varnishes
SIST EN ISO 2431:2012 en,fr
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 2431:2012

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SIST EN ISO 2431:2012


EUROPEAN STANDARD
EN ISO 2431

NORME EUROPÉENNE

EUROPÄISCHE NORM
November 2011
ICS 87.040 Supersedes EN ISO 2431:1996
English Version
Paints and varnishes - Determination of flow time by use of flow
cups (ISO 2431:2011)
Peintures et vernis - Détermination du temps d'écoulement Beschichtungsstoffe - Bestimmung der Auslaufzeit mit
au moyen de coupes d'écoulement (ISO 2431:2011) Auslaufbechern (ISO 2431:2011)
This European Standard was approved by CEN on 26 November 2011.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2011 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 2431:2011: E
worldwide for CEN national Members.

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SIST EN ISO 2431:2012
EN ISO 2431:2011 (E)
Contents Page
Foreword .3
2

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SIST EN ISO 2431:2012
EN ISO 2431:2011 (E)
Foreword
This document (EN ISO 2431:2011) has been prepared by Technical Committee ISO/TC 35 "Paints and
varnishes" in collaboration with Technical Committee CEN/TC 139 “Paints and varnishes” the secretariat of
which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by May 2012, and conflicting national standards shall be withdrawn at the
latest by May 2012.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 2431:1996.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 2431:2011 has been approved by CEN as a EN ISO 2431:2011 without any modification.

3

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SIST EN ISO 2431:2012

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SIST EN ISO 2431:2012
INTERNATIONAL ISO
STANDARD 2431
Fifth edition
2011-11-15
Paints and varnishes — Determination of
flow time by use of flow cups
Peintures et vernis — Détermination du temps d’écoulement au moyen
de coupes d’écoulement
Reference number
ISO 2431:2011(E)
©
ISO 2011

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SIST EN ISO 2431:2012
ISO 2431:2011(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2011
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO’s
member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2011 – All rights reserved

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SIST EN ISO 2431:2012
ISO 2431:2011(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Temperature considerations . 2
5 Apparatus . 2
5.1 Flow cups . 2
5.2 Supplementary apparatus . 5
6 Sampling . 6
7 Procedure . 6
7.1 Preliminary check for Newtonian flow . 6
7.2 Determination of flow time . 6
8 Marking of products tested . 7
9 Precision . 7
9.1 General . 7
9.2 Repeatability limit � . 8
9.3 Reproducibility limit � . 8
10 Test report . 8
Annex A (normative) Checking flow cups for wear and tear .10
Annex B (informative) Conversion of flow times from one temperature to another .12
Bibliography .15
© ISO 2011 – All rights reserved iii

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SIST EN ISO 2431:2012
ISO 2431:2011(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 2431 was prepared by Technical Committee ISO/TC 35, Paints and varnishes, Subcommittee SC 9,
General test methods for paints and varnishes.
This fifth edition cancels and replaces the fourth edition (ISO 2431:1993), which has been technically revised.
It also incorporates the Technical Corrigenda ISO 2431:1993/Cor.1:1994 and ISO 2431:1993/Cor.2:1999.
The main technical changes are as follows:
a) the curves in Figures 2 to 5 have been placed in a single figure (Figure 2) and the equations for the
conversion of flow time to kinematic viscosity and vice versa represented by the curves in these figures
have been moved from the figures to a table (Table 1);
b) the accuracy of the stopwatch used is no longer specified;
c) a clause has been added describing the marking of products tested to indicate the results of the test;
d) the procedure for checking the flow cups for wear and tear has been revised to include two alternative
methods (one using a certified reference material or secondary working standard, the other using a
certified flow cup) and has been moved to an informative annex;
e) the former Annex A on the use of flow cups for the adjustment of paint consistency has been deleted;
f) a new annex describing the conversion of flow times from one temperature to another has been added.
iv © ISO 2011 – All rights reserved

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SIST EN ISO 2431:2012
ISO 2431:2011(E)
Introduction
The first edition of this International Standard, published in 1972, specified only one flow cup of orifice diameter
4 mm. The second edition specified three flow cups of orifice diameter 3 mm, 4 mm and 6 mm. The third edition
corrected errors in Figures 2 and 4 and the equations for those figures. The fourth edition specified four flow
cups of orifice diameter 3 mm, 4 mm, 5 mm and 6 mm. The main changes made in this fifth edition are given
in the foreword.
As is well known, many countries over the years have developed their own standard flow cups and the difficulty
in correlation between them has led to considerable confusion in comparing values. The standardization of an
improved design of flow cup has been recommended after careful consideration, by an expert working group,
of the role of flow cups for the measurement of the flow time of paints, varnishes and related products.
It is recognized that flow times are reproducible only for products of Newtonian or near-Newtonian flow
properties. This effectively limits their practical use. Nevertheless, for checking purposes, these flow cups do
serve a useful purpose. Furthermore, the measurement of flow time is often used to confirm the application
consistency.
Paints often contain flow-arresting agents to confer increased viscosity. Such paints exhibit non-Newtonian
flow properties. Their viscosity during application can only be properly assessed using viscometers such as
that described in ISO 3219.
Resins and varnishes can exhibit Newtonian or near-Newtonian flow at much higher viscosities than most
paints and, where this applies, flow cups can provide a useful means of controlling the consistency. To meet
2
this requirement, this International Standard provides flow cups suitable for viscosities up to about 700 mm /s.
With thixotropic materials, stirring or other such mechanical disturbance immediately before testing will reduce
the flow time compared with that for an unstirred sample. With such materials, uncertain and variable flow time
values are obtained with all the flow cups. The repeatability and reproducibility limits given in Clause 9 cannot
be achieved in the determination of the flow time of such materials.
© ISO 2011 – All rights reserved v

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SIST EN ISO 2431:2012

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SIST EN ISO 2431:2012
INTERNATIONAL STANDARD ISO 2431:2011(E)
Paints and varnishes — Determination of flow time by use of
flow cups
1 Scope
1.1 This International Standard specifies a method for determining the flow time of paints, varnishes and
related products that can be used to control consistency.
1.2 Four flow cups of similar dimensions, but having orifice diameters of 3 mm, 4 mm, 5 mm and 6 mm, are
specified. Two methods for checking the flow cups for wear and tear are given (see Annex A).
Flow cups with a replaceable jet are not covered by this International Standard as the close tolerances on the
supply of the material under test to the jet are not met.
Commonly used dipping flow cups are also not covered by this International Standard. In general, the fabrication
tolerances for such flow cups are greater than those of the flow cups specified in this International Standard.
Therefore flow time determinations with dipping flow cups give a precision which is lower than that obtained
with the flow cups specified in this International Standard (see Clause 9).
1.3 The method is limited to testing materials for which the breakpoint of the flow from the orifice of the flow
cup can be determined with certainty. This point is difficult to determine and reproduce for materials with flow
times near the upper limit of the measurement range (100 s) due to slowing-down effects.
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 1513, Paints and varnishes — Examination and preparation of test samples
ISO 15528, Paints, varnishes and raw materials for paints and varnishes — Sampling
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
flow time
t
time that elapses from the moment when the material under test starts to flow from the orifice of the filled flow
cup to the moment when the flow stream of material first breaks off close to the orifice
3.2
Newtonian flow
type of flow exhibited by a material in which, at a constant temperature, the ratio of the shear stress to the shear
rate does not vary either with time or with the shear rate
NOTE When variations in this ratio are small, the effect on viscosity of mechanical disturbance, such as stirring, is
negligible and the material is said to have near-Newtonian flow.
© ISO 2011 – All rights reserved 1

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SIST EN ISO 2431:2012
ISO 2431:2011(E)
3.3
non-Newtonian flow
type of flow exhibited by a material in which, at a constant temperature, the ratio of the shear stress to the shear
rate varies either with time or with shear rate
3.4
kinematic viscosity
ν
ratio of the dynamic viscosity to the density of the liquid
2
NOTE The SI base unit for kinematic viscosity is metres squared per second (m /s).
4 Temperature considerations
The effect of temperature on flow time is highly significant with respect to application properties and varies with
the type of product.
For reference purposes, (23,0 ± 0,5) °C is specified as the test temperature in this International Standard.
However, it might be more convenient to carry out comparative testing at some other agreed temperature (for
example, 25 °C) because of prevailing temperature conditions (see also Annex B).
For control by flow time, the test sample and flow cup shall be conditioned to an agreed or specified temperature
and it shall be ensured that the temperature variation does not exceed 0,5 °C during testing. The flow cup shall
be in a place which is free from draughts.
5 Apparatus
5.1 Flow cups
5.1.1 Dimensions
The dimensions of the ISO flow cups and the tolerances allowed in manufacture shall be as shown in Figure 1.
NOTE The most critical tolerance is the internal diameter of the jet of the flow cup, because the flow time is inversely
proportional to the fourth power of this dimension.
5.1.2 Material
The jet of the flow cup shall be made of stainless steel or sintered carbide, and the body of the flow cup shall
be made of a material which is corrosion-resistant and is not affected by the products to be tested.
5.1.3 Construction
The dimensions not specified, such as wall thickness, shall be such that no distortion of the flow cup can occur
in use. The external shape should preferably be as shown in Figure 1, but may be modified for convenience of
use, or manufacture, provided that the protruding jet of the flow cup is prot
...

SLOVENSKI STANDARD
oSIST prEN ISO 2431:2010
01-september-2010
%DUYHLQODNL'RORþDQMHL]WRþQHJDþDVD]XSRUDERL]WRþQLKþDã ,62',6

Paints and varnishes - Determination of flow time by use of flow cups (ISO/DIS
2431:2010)
Beschichtungsstoffe - Bestimmung der Auslaufzeit mit Auslaufbechern (ISO/DIS
2431:2010)
Peintures et vernis - Détermination du temps d'écoulement au moyen de coupes
d'écoulement (ISO/DIS 2431:2010)
Ta slovenski standard je istoveten z: prEN ISO 2431
ICS:
87.040 Barve in laki Paints and varnishes
oSIST prEN ISO 2431:2010 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN ISO 2431:2010

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oSIST prEN ISO 2431:2010


EUROPEAN STANDARD
DRAFT
prEN ISO 2431
NORME EUROPÉENNE

EUROPÄISCHE NORM

June 2010
ICS 87.040 Will supersede EN ISO 2431:1996
English Version
Paints and varnishes - Determination of flow time by use of flow
cups (ISO/DIS 2431:2010)
Peintures et vernis - Détermination du temps d'écoulement Beschichtungsstoffe - Bestimmung der Auslaufzeit mit
au moyen de coupes d'écoulement (ISO/DIS 2431:2010) Auslaufbechern (ISO/DIS 2431:2010)
This draft European Standard is submitted to CEN members for parallel enquiry. It has been drawn up by the Technical Committee
CEN/TC 139.

If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations which
stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other language
made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the
same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.


EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN ISO 2431:2010: E
worldwide for CEN national Members.

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oSIST prEN ISO 2431:2010
prEN ISO 2431:2010 (E)
Contents Page
Foreword .3

2

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oSIST prEN ISO 2431:2010
prEN ISO 2431:2010 (E)
Foreword
This document (prEN ISO 2431:2010) has been prepared by Technical Committee ISO/TC 35 “Paints and
varnishes” in collaboration with Technical Committee CEN/TC 139 “Paints and varnishes” the secretariat of
which is held by DIN.
This document is currently submitted to the parallel Enquiry.
This document will supersede EN ISO 2431:1996.
Endorsement notice
The text of ISO/DIS 2431:2010 has been approved by CEN as a prEN ISO 2431:2010 without any
modification.
3

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oSIST prEN ISO 2431:2010

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oSIST prEN ISO 2431:2010
DRAFT INTERNATIONAL STANDARD ISO/DIS 2431
ISO/TC 35/SC 9 Secretariat: BSI
Voting begins on: Voting terminates on:
2010-06-17 2010-11-17
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION • МЕЖДУНАРОДНАЯ ОРГАНИЗАЦИЯ ПО СТАНДАРТИЗАЦИИ • ORGANISATION INTERNATIONALE DE NORMALISATION
Paints and varnishes — Determination of flow time by use of
flow cups
Peintures et vernis — Détermination du temps d'écoulement au moyen de coupes d'écoulement
(Revision of fourth edition of ISO 2431:1993, of ISO 2431:1993/Cor.1:1194 and of ISO 2431:1993/Cor.2:1999)
ICS 87.040

ISO/CEN PARALLEL PROCESSING
This draft has been developed within the International Organization for Standardization (ISO), and
processed under the ISO-lead mode of collaboration as defined in the Vienna Agreement.
This draft is hereby submitted to the ISO member bodies and to the CEN member bodies for a parallel
five-month enquiry.
Should this draft be accepted, a final draft, established on the basis of comments received, will be
submitted to a parallel two-month approval vote in ISO and formal vote in CEN.
In accordance with the provisions of Council Resolution 15/1993 this document is circulated in
the English language only.
Conformément aux dispositions de la Résolution du Conseil 15/1993, ce document est distribué
en version anglaise seulement.
To expedite distribution, this document is circulated as received from the committee secretariat.
ISO Central Secretariat work of editing and text composition will be undertaken at publication
stage.
Pour accélérer la distribution, le présent document est distribué tel qu'il est parvenu du
secrétariat du comité. Le travail de rédaction et de composition de texte sera effectué au
Secrétariat central de l'ISO au stade de publication.
THIS DOCUMENT IS A DRAFT CIRCULATED FOR COMMENT AND APPROVAL. IT IS THEREFORE SUBJECT TO CHANGE AND MAY NOT BE
REFERRED TO AS AN INTERNATIONAL STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS BEING ACCEPTABLE FOR INDUSTRIAL, TECHNOLOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT, WITH THEIR COMMENTS, NOTIFICATION OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPORTING DOCUMENTATION.
©
International Organization for Standardization, 2010

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oSIST prEN ISO 2431:2010
ISO/DIS 2431
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oSIST prEN ISO 2431:2010
ISO/DIS 2431
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.1
3 Terms and definitions .1
4 Temperature considerations .2
5 Apparatus.2
6 Sampling.7
7 Procedure.7
8 Designation .8
9 Precision.9
10 Test report.9
Annex A (informative) Verification .10
Annex B (informative) Conversion of flow times in relation to the temperature.13
Bibliography.16

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oSIST prEN ISO 2431:2010
ISO/DIS 2431
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 2431 was prepared by Technical Committee ISO/TC 35, Paints and varnishes, Subcommittee SC 9, and
by Technical Committee CEN/TC 139, Paints and varnishes in collaboration.
This fifth edition cancels and replaces the fourth edition (ISO 2431:1993), which has been technically revised.
The main technical changes are:
a) the two Technical Corrigenda are incorporated in the text;
b) the calibration equations are moved from the figures to clause 5.1.4;
c) the accuracy of the stopwatch is deleted because this is part of inspection equipment monitoring;
d) a designation is added;
e) the verification is revised and moved to an informative annex;
f) a second method for the verification is introduced;
g) the use of a secondary standard and a certified flow cup for the verification are added;
h) Annex A on the use of flow cups for the adjustment of paint consistency is revised.
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oSIST prEN ISO 2431:2010
ISO/DIS 2431
Introduction
The first edition of this International Standard, published in 1972, specified only one flow cup of orifice
diameter 4 mm. The second edition, specified three flow cups of orifice diameter 3 mm, 4 mm, and 6 mm. The
third edition corrected errors in Figures 2 and 4 and the equations for those Figures. The fourth edition
specifies four flow cups of orifice diameter 3 mm, 4 mm, 5 mm and 6 mm. The fifth edition corrects Figure 1,
introduces a designation for the test and revises the verification of the flow cups.
As is well known, many countries over the years have developed their own standard flow cups and the
difficulty in correlation between them has led to considerable confusion in comparing values. The
standardization of an improved design of flow cups has been recommended after careful consideration, by an
expert working group, of the role of flow cups for the measurement of flow time of paints, varnishes and
related products.
It is recognized that the flow times are reproducible only for the products of Newtonian or near-Newtonian flow
properties. This effectively limits their practical use. Nevertheless, for checking purposes, these flow cups do
serve a useful purpose. Furthermore, the measurement of flow time is often used to confirm the application
consistency.
Paints often contain flow-arresting agents to confer increased viscosity. Such paints exhibit non-Newtonian
flow properties. Their viscosity during application can only be properly assessed using viscometers operating
at high velocity gradients, such as that described in ISO 3219.
Resins and varnishes can exhibit Newtonian or near-Newtonian flow at much higher viscosities than most
paints and, where this applies, flow cups can provide a useful mean of controlling the consistency. To meet
2
this requirement, this International Standard provides flow cups suitable for viscosities up to about 700 mm /s.
Recommendations for the use of flow cups for the verification of paint consistency are given in Annex A.
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oSIST prEN ISO 2431:2010
DRAFT INTERNATIONAL STANDARD ISO/DIS 2431

Paints and varnishes — Determination of flow time by use of
flow cups
1 Scope
1.1 This International Standard specifies a method for determining the flow time of paints, varnishes and
related products that may be used to control consistency. A method for the adjustment of paints to the correct
application consistency at the application temperature is described in Annex A.
1.2 Four flow cups of similar dimensions, but having orifice diameters of 3 mm, 4 mm, 5 mm and 6 mm, are
specified. The method for their calibration is given.
1.3 The method is limited to testing materials for which the breakpoint of the flow from the orifice of the flow
cup can be determined with certainty. This point is difficult to determine and reproduce for materials with flow
times in excess of 100 s due to slowing-down effects.
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 1513, Paints and varnishes — Examination and preparation of samples for testing
ISO 15528, Paints, varnishes and raw materials for paints and varnishes — Sampling
3 Terms and definitions
For the purposes of this International Standard, the following terms and definitions apply.
3.1
flow time
t
time that elapses from the moment when the material under test starts to flow from the orifice of the filled cup
to the moment when the flow stream of material first breaks close to the orifice
3.2
Newtonian flow
type of flow exhibited by a material in which, at a constant temperature, the ratio of the shear stress to the
velocity gradient does not vary either with time or with the velocity gradient
NOTE When variations in this ratio are small, the effect on viscosity of mechanical disturbance, such as stirring, is
negligible and the material is said to have near-Newtonian flow.
3.3
Non-Newtonian flow
type of flow exhibited by a material in which, at a constant temperature, the ratio of the shear stress to the
velocity gradient varies either with time or with rate of shear
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oSIST prEN ISO 2431:2010
ISO/DIS 2431
NOTE For example, with so-called thixotropic materials, stirring or other such mechanical disturbance immediately
before test will reduce the flow time below that for an unstirred sample. With such materials, uncertain and variable values
for flow time are obtained in all flow cups. In addition flow time determinations of such materials are resulted in lower
precision data as specified in Clause 8.
3.4
dynamic viscosity
η
ratio of the shear stress to the velocity gradient
3.5
kinematic viscosity
ν
ratio of the dynamic viscosity to the density of the liquid
4 Temperature considerations
The effect of temperature on flow time is highly significant with respect to application properties and varies
with the type of product.
For international reference purposes, it is essential to standardize one test temperature and (23,0 ± 0,5) °C is
specified in this International Standard. However, it might be more convenient to carry out comparative testing
at some other agreed temperature (for example, 25 °C) because of prevailing temperature conditions (see
also Annex B).
For control by flow time, the test sample and flow cup shall be conditioned to an agreed or specified
temperature and it shall be ensured that the temperature variation does not exceed 0,5 °C during testing.
5 Apparatus
5.1 Flow cups
5.1.1 Dimensions
The dimensions of the ISO flow cups and th
...

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