EN ISO 3521:1999

SLOVENSKI STANDARD
01-maj-2000
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Plastics - Unsaturated polyester and epoxy resins - Determination of overall volume
shrinkage (ISO 3521:1997)
Kunststoffe - Ungesättigte Polyester und Epoxidharze - Bestimmung der
Gesamtvolumenschwindung (ISO 3521:1997)
Plastiques - Résines d'époxydes et de polyesters non saturés - Détermination du retrait
global en volume (ISO 3521:1997)
Ta slovenski standard je istoveten z: EN ISO 3521:1999
ICS:
83.080.10 Duromeri Thermosetting materials
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL
STANDARD
Second edition
1997-03-O 1
- Unsaturated polyester and epoxy
Plastics
Determination of overall volume
resins -
shrinkage
Plastiques - /Sines d ’6poxydes et de polyesters non sat&s -
D&termination du retrait global en volume
Reference number
IS0 3521 :I 997(E)
IS0 3521:1997(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide
federation 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
collaborates closely with the International Electrotechnical Commission
(IEC) 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 IS0 3521 was prepared by Technical Committee
ISODC 61, Plastics, Subcommittee SC 12, Thermosetting materials.
This second edition cancels and replaces the first edition (IS0 3521:1976),
of which it constitutes a technical revision.
0 IS0 1997
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 the publisher.
International Organization for Standardization
Case postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
IS0 3521:1997(E)
INTERNATIONAL STANDARD @ IS0
Plastics - Unsaturated polyester and epoxy resins -
Determination of overall volume shrinkage
1 Scope
This International Standard specifies a method for the determination of the overall volume shrinkage of unsaturated
polyester and epoxy resins.
2 Normative reference
The following standard contains provisions which, through reference in this text, constitute provisions of this
International Standard. At the time of publication, the edition indicated was valid. All standards are subject to
revision, and parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent edition of the standard indicated below. Members of IEC and IS0 maintain
registers of currently valid International Standards.
IS0 1675:1985, Plastics - Liquid resins - Determination of density by the pyknometer method.
3 Definition
For the purposes of this International Standard, the following definition applies.
3.1 overall volume shrinkage: The sum of the shrinkage during curing and the shrinkage after curing of a
casting when cooled to ambient temperature.
4 Principle
The overall volume shrinkage is calculated from the specific gravity of a last specimen before and after curing.
First, the specific gravity of the resin composition is determined
a) at the initial temperature of mixing of the components, excluding the initiators normally added to unsaturated
polyesters (see 6.1.3, note 1);
b) at 23 “C after curing and conditioning of the last specimen.
The overall volume shrinkage is then calculated as a percentage of the change in the specific gravity before and
after curing, as follows:
Uncured specific gravity - Cured specific gravity x 1 00
Overall volume shrinkage =
Uncured specific gravity
IS0 3521:1997(E) @ IS0
The specific gravity at the moment of mixing is determined for the mixed components at known intervals and the
results extrapolated to zero time.
For components that react at elevated temperature, the specific gravity of the mixture is determined by calculation
from the individual specific gravities of the components.
The specific gravity at 23 *C of the last specimen after curing and conditioning is determined by weighing in
silicone oil.
5 Apparatus
5.1 Balance, accurate to 1 mg, with a device for measurement of specific gravity (if possible, a rapid-acting
balance).
5.2 Sinker, weighing 25 g + 5 g, and of dimensions such that wall effects are avoided. Its volume at the curing
temperature and its volume at 23 *C +, 0,l *C shall be known.
containing oil whose specific gravity at the hardening
5.3 Temperature-stabilized silicone-oil bath,
temperature and at 23 *C +, 0,l *C is known.
5.4 Test tubes, length approximately 180 mm. diameter 20 mm.
5.5 Stopwatch.
5.6 Desiccator.
6 Procedure
6.1 Determination of specific gravity of compositions that cure at temperatures higher
than ambient
6.1 .I Preparation of apparatus
-3 ml, the volume Vs of the sinker at the curing temperature of the composition.
Determine, to an accuracy of + 10
Weigh the sinker in air at ambient temperature (mass ms). Then weigh the sinker together with its suspension wire
in silicone oil maintained at the curing temperature of the composition (mass ms+w).
Determine the mass (mass m,) of the suspension wire in air at ambient temperature.
If the specific gravity of the silicone oil at the curing temperature of the composition is not known, determine it in
accordance with IS0 1675 but at the curing temperature.
6.1.2 Epoxy resins
Weigh out each of the components in the proportions used to form the composition, taking a quantity large enough
to carry out the determination described below and to cast the test specimen prepared in 6.3.
Heat each of the components separately to the curing temperature. Mix the components, starting the stopwatch
immediately after the introduction of the last component. This moment is taken as zero time. Continue to mix until
a homogeneous mixture is obtained, then pour the mixture into the test tube all at once. Hang the sinker
(prehe
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