EN ISO 3681:1998

SLOVENSKI STANDARD
01-avgust-1998
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Binders for paints and varnishes - Determination of saponification value - Titrimetric
method (ISO 3681:1996)
Bindemittel für Beschichtungsstoffe - Bestimmung der Verseifungszahl - Titrimetrisches
Verfahren (ISO 3681:1996)
Liants pour peintures et vernis - Détermination de l'indice de saponification - Méthode
titrimétrique (ISO 3681:1996)
Ta slovenski standard je istoveten z: EN ISO 3681:1998
ICS:
87.060.20 Veziva Binders
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL
STANDARD
Third edition
1996-06-01
Binders for paints and varnishes -
Determination of saponification value -
Titrimetric method
Liants pour peintures et vernis - Dktermination de I’indice de
saponification - Mkthode titrim&rique
Reference number
IS0 3681 :I 996(E)
IS0 3681:1996(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide fed-
eration of national standards bodies (IS0 member bodies). The work of
preparing International Standards is normally carried out through IS0
technical committees. Each member body interested in a subject for
which a technical committee has been established has the right to be rep-
resented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. IS0 col-
laborates closely with the International Electrotechnical Commission (IEC)
on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are cir-
culated 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 IS0 3681 was prepared by Technical Committee
lSO/TC 35, Paints and varnishes, Subcommittee SC 10, Test methods for
binders for paints and varnishes.
This third edition cancels and replaces the second edition (IS0 3681:1983),
which has been technically and editorially revised. The main change is that
the saponification value is no longer related to 1 g of non-volatile matter of
the product but to 1 g of the product itself.
Annex A forms an integral part of this International Standard.
0 IS0 1996
All rights reserved. Unless otherwise specified, no part of this publication may be repro-
duced or utilized in any form or by any means, electronic or mechanical, including photo-
copying and microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
INTERNATIONAL STANDARD 0 IS0 IS0 3681:1996(E)
Binders for paints and varnishes - Determination of
saponification value - Titrimetric method
IS0 8421984, Raw materials for paints and var-
1 Scope
nishes - Sampling.
This International Standard specifies a titrimetric
IS0 3696: 1987, Water for analytical labora tory use -
method for determining the esterified-acid content in
Specification and test methods.
binders for paints and varnishes, free acids and acid
anhydrides being necessarily included in the result ob-
tained.
3 Definitions
Because different binders vary in their resistance to
saponification, this International Standard is of limited
For the purposes of this International Standard, the
applicability. If necessary, completeness of saponifi-
following definitions apply.
cation may be checked by repeating the test under
more severe conditions achieved by the use of longer
3.1 saponification: The formation of the alkali metal
saponification time, more concentrated potassium hy-
salts of derivatives of organic acids.
droxide solution, or a higher-boiling alcohol as solvent.
3.2 saponification value: The number of milligrams
Annex A specifies a procedure suitable for binders
of potassium hydroxide (KOH) required for the saponi-
that saponify with difficulty.
fication of 1 g of the product tested.
The method is not applicable to those materials that
show further reaction with alkalis beyond normal sap-
onification.
4 Principle
After a preliminary test to determine the saponifi-
2 Normative references
cation conditions (concentration of potassium hydrox-
ide solution, saponification time, etc.) for the product
to be tested, a test portion is boiled under reflux with
The following standards contain provisions which,
potassium hydroxide solution under these conditions.
through reference in this text, constitute provisions of
The hot solution is titrated with standard volumetric
this International Standard. At the time of publication,
hydrochloric acid, either in the presence of a colour
the editions indicated were valid. All standards are
indicator or potentiometrically.
subject to revision, and parties to agreements based
on this International Standard are encouraged to in-
vestigate the possibility of applying the most recent
editions of the standards indicated below. Members
5 Reagents
of IEC and IS0 maintain registers of currently valid In-
ternational Standards.
During the analysis, use only reagents of recognized
analytical grade, and only water of at least grade 3 pu-
IS0 385-l :I 984, Laboratory glassware - Burettes -
rity as defined in IS0 3696.
Part 1: General requirements.
IS0 648: 1977, Laboratory glassware - One-mark pip- 5.1 Toluene, or other suitable unsaponifiable sol-
vent.
ettes.
0 IS0
IS0 3681:1996(E)
tion time to at least 2 h and/or by using a 2 mol/l po-
5.2 Potassium hydroxide solution, in isopropanol,
tassium hydroxide solution or a solution of potassium
ethanol or methanol, c(KOH) = 0,5 mol/l.
hydroxide in an alcohol that has a boiling point dis-
NOTE 1 If more severe conditions for saponification are
tinctly higher than that of ethanol, for example 1,2-
needed, 2 mol/l ethanolic potassium hydroxide solution may
ethanediol (ethylene glycol) or 2,2 ’-oxydiethanol
be used, or 1,Zethanediol (ethylene glycol) or 2,2 ’-
(diethylene glycol).
oxydiethanol (diethylene glycol) may be used as the solvent
(see clause 8 and annex A).
If no increase in the final (i.e mean) result (see 10.1) is
obtained using the more intense conditions, the test
Where isopropanol can be used instead of ethanol or
may be carried out using this International Standard. If
methanol, it shall be used. The applicability of the sol-
a higher value is obtained which is not further in-
ution in isopropanol is comparable to that of an etha-
creased by again intensifying the test conditions, this
nolic solution and its toxicity is less than that of a
International Standard may be followed but using and
methanolic solution.
noting the intensified conditions applied. If a constant
result is not obtained even under the most severe
Hydrochloric acid, standard volumetric solution,
5.3
conditions of saponification, the method to be used
c(HCI) = 0,5 mol/l, in a mixture of 4 parts by volume of
shall be agreed between the interested parties.
methanol and 1
...