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INTERNATIONAL
STANDARD
6427
Second edition
19924 2-l 5
Plastics - Determination of matter extractable
by organic solvents (conventional methods)
Plasfiques - LXtermination des matitkes extractibles par des solvants
organiques (methodes conventionnelles)
Reference number
ISO 6427: 1992(E)
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ISO 6427:1992(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, govern-
mental and non-governmental, in liaison with ISO, also take patt in the
work. ISO 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 Inter-
national Standard requires approval by at least 75% of the member
bodies casting a vote.
International Standard ISO 6427 was prepared by Technical Committee
ISO/TC 61, Plastics, Su b-Committee SC 5, Physical-Chemical properties.
This second edition cancels and replaces the first edition
(ISO 6427:1982), of which it constitutes a technical revision concerning
principally the table.
Annexes A and B form an integral part of this International Standard.
0 ISO 1992
All rights reserved. No part of this publication may be reproduced or utilized in any form
or by any means, electronie or mechanical, including photocopying and microfilm, without
Permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-121 1 Geneve 20 l Switzerland
Printed in Switzerland
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ISO 6427:1992(E)
Introduction
There are several very similar national and international Standards for
determination of the percentage of extractable matter with only slight
differentes in procedures. To facilitate the work of the laboratory staff,
which has to carry out these determinations on various plastics prod-
ucts, the generally applicable methods are described in this Inter-
national Standard.
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INTERNATIONAL STANDARD ISO 6427:1992(E)
Plastics - Determination of matter extractable by organic
solvents (conventional methods)
cation, the editions indicated were valid. All stan-
1 Scope
dards are subject to revision, and Parties to
agreements based on this International Standard
1 .l This International Standard specifies methods are encouraged to investigate the possibility of ap-
for the determination of components in plastics that plying the most recent editions of the Standards in-
tan be extracted by hot organic liquids near their dicated below. Members of IEC and ISO maintain
boiling Points. For one special case a so-called cold registers of currently valid International Standards.
extraction method is given in annex B.
ISO 59:1976, Plastics - Phenolic mouldings - Deter-
mination of acetone-soluble matter.
components tan be
1.2 The extractable
plasticizers,
monomers, oligomers, polymers,
ISO 308:1981, Plastics - Phenolic moulding maferials
stabilizers, etc. The kind and percentage of
- Determination of acetone-soluble matter (apparent
extractable matter influence the properties of plas-
resin content of material in the unmoulded state).
tics.
ISO 383:1976, Laboratory glassware - Interchange-
able conical ground joints.
1.3 The recommended extraction liquid depends
on the type of plastic and on the purpose of the de-
ISO 565:1990, Test sieves - Metal wire cloth, perfor-
termination (see table 1). The extracted amounts of
ated metal plate and electroformed sheet - Nominal
special constituents are often not quantitative in the
sizes of openings.
sense of analytical chemistry.
ISO 1773:1976, Laboratory glassware - Boiling flasks
(narrow-necked).
1.4 This International Standard does not apply to
plastics that come into contact with food or drinking
ISO 1872.1:1986, Plasfics - Polyethylene (PE) and
watet-. Special regulations for those plastics are es-
ethylene copolymer thermoplastics - Part 1: Desig-
tablished in many countries. In Order to test plastics
nation.
for compliance with these regulations, methods
other than those given in this International Standard
ISO 1875:1982, Plastics - Plasticized cellulose acet-
are used in most cases. The methods of this Inter-
ate - Determination of matter extractable by diethyl
national Standard are not intended to be used for
ether.
migration tests.
1.5 If this International Standard is used to test
plastics other than those mentioned in table 1, the
3 Reagents and materials
operating conditions shall be agreed upon by the
interested Parties.
3.1 Extraction liquid, of recognized analytical
grade, to be selected according to the requirements
2 Normative references
of the plastic material being tested (see table 1).
The following Standards contain provisions which,
through reference in this text, constitute provisions
of this International Standard. At the time of publi- 3.2 Anti-bumping granules.
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ISO 6427:1992(E)
Dimensions in millimetres
3.3 Giass wooi, pre-extracted.
4 Apparatus
4.1 Miii, for reducing the Sample to the required
grain size.
A mill in which the Sample is tut between rotating
and stationary blades is preferred. Large pieces tan
be reduced in size with a pair of shears before they
are fed into the mill.
4.2 Set of sieves, complying with the requirements
of ISO 565.
4.3 Fiat-bottomed fiask, of suitable capacity, for
example 250 ml, complying with the r,equirements
of ISO 1773, with ground-glass neck complying with
the requirements of ISO 383.
Extractor
trap
4.4 Extraction apparatus, of such a design that the
crucible or thimble is heated by the rising vapour of
the extraction liquid.
r
I I
TI-@
4.4.1 Soxhiet extractor, as shown in figure 1.
l
Thimble
4.4.2 Other extractors, for example that designed
by Twisselmann (see figure2), may be used, if they
give the Same results as the Soxhlet extractor.
4.5 Container, for test portion to be extracted.
4.51 Ceiiuiose Paper thimbie, of suitable size, for
example diameter 33 mm and length 94 mm.
Solvent
4.5.2 Metai wire basket, of the Same dimensions as
/-
the thimble (4.5.1).
Heater
4.53 Giass-fiiter crucibie, pore size 40 Pm to
100 Pm.
NOTE 1 The choice of a suitable Container for the ex-
traction is very important. The weight of the cellulose
thimble (4.51) depends on its moisture content, and this
tan lead to variable results when weighing. The metal
wir-e basket (4.52) cannot be used with a powder Sample
or if a Chemical reaction is possible between the metal
and any of the components of the plastic. Difficulties tan
be caused by Penetration of components of the plastic into
the pores of the glass-filter crucible (4.5.3) and sub-
- Extraction apparatus capabie of
Figure 1
sequent swelling.
receiving the thimbie (4.51) or other Sample
Containers
2
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ISO 6427:1992(E)
4.6 Reflux condenser, fitted with a ground-glass
5 Preparation of test Sample
cone to fit the extraction apparatus (4.4), for example
a Dimroth condenser.
5.1 The plastics material or p ‘lastics product shall
be free of dust and foreign matter. If the material or
4.7 Heating device, which doe,s not use a naked
product has 10 be cleaned, organic solvent shall be
flame and is’ explosion-proof, suitahle for use with
used only at room temperature.
the flask (4.3).
5.2 The Sample of plastic shall be reduced to small
4.8 Balance, accurate to 0,;1 mg.
pieces, for example by grinding in a suitable mill
(4.1), but shall not be heated m&e than necessary.
In some cases it may be necessaty to add solid
4.9 Desiccator, containing Calcium chloride or
carbon dioxide to prevent heat build-up during
silica ge ’l.
grinding. The reduction in size may also be done by
the use. of a razor blade or a pair of scissors, or a
4.10 Distillation equipment.
file for hard materials. The Portion of the Sample of
specified granular size (see table 1) shall be kept in
One of the following devices shall be used:
a closed bottle until tested. Films with a thickness
of less than 0,5 mrn rnai be tut into small fragments
for insertion into the thimble.
4.10.1 Rotary evaporator.
4.10.2 Distillation apparatus, fitted with a Vigreux
6 Number of tests
or equivalent distillation column of length at least
400 mm.
At least two determinations shali be made.
4.11 Vacuum oven or oven with fresh air
circulation, explosion-proof, capable of maintaining
7 Procedure
a temperature of 105 “C.
The speci,fic details of the procedure to be used de-
4.12 Evaporating dish, of suitable capacity, for ex- pend on the material to be tested and are given in
ample 200 ml. table 1. The general procedure is described here-
after.
Dimensions in mill met res
7.1 Dry the Paper thimble (4.5.1), wire basket
(4.5.2) or filter crticible (4.5.3) for 1 h in the oven
\ Ground-glass
(4.11) at the Same temperature as used later for the
socket 45/40
drying of the plastic tested; allow to cool to room
temperature in the dessicator (4.9) and weigh in a
Vacuum
closed weighing bottle.
jacket
NOTE 2 In special ‘cases it may be necessary to it-e-
extract the thimble with th& extraction liquid (3.1).
Weigh a test Portion, of the mass given ,in table 1, to
the nearest 1 mg in the thimble, basket or crucible,
cover it with a piece of glass wool (3.3) and put it
into the extraction apparatus (4.4). If the expscted
content of extractable material is below
0,5 % (m/m) increase the mass of the test portion to
obtain a residue of at least 25 mg. Pour the appro-
priate volume of extraction liquid (3.l),into the flask
Ground-glass
(4.3). One or two anti-bumpin,g granules (3.2) may
cone 29/32
be added. Mount the extractor (4.4) and the reflux
condenser (4.6) on the flask and adjust the heating
device (4.7) so that when a Soxhlet-type extractor
(4.4.1) is used the extraction liquid syphons several
Figure 2 -
Extractor of Twisselmann type with times per hour. For the number of syphonings and
vacuum jacket the extraction time see table 1.
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ISO 6427:1992(E)
7.2 Carry out the extraction. Depending on the type
m2
rn,xlOO
of plastic extracted (see table l), further process the
residue in accordance with 7.3 and/or the extract in
accordance with 7.4.
is the mass, in grams of the test por-
9
mo
7.3 When the extraction is finished, take the
tion;
thimble, basket or crucible out of the extractor, allow
it to drain and air-dry, and then dry it under the
is the mass, in grams, of non-
m1
conditions given in table 1 (depending on the kind
extractable matter remaining in the
of extraction liquid). Allow it to cool to room tem-
extraction vessel after extraction;
perature in the desiccator (4.9) and weigh the
thimble, basket or crucible to the nearest 1 mg.
is the mass, in grams, of extractable
When a thimble is used, weigh the thimble and its
matter in the
evaporating dish.
contents in a closed weighing bottle.
8.2 Repeat the test if the two individual values dif-
7.4 The extraction liquid in the flask may be either
fer by more than 5 % in relative value,. unless other
distilled to about 20 ml using the rotary evaporator
limits are specified in table 1.
(4.10.1) or distillation apparatus (4.10.2) or the liquid
may be placed directly in a predried and weighed
9 Precision t
evaporating dish (4.12). In the case of distillation ,of
the main amount of the liquid, transfer the remaining
The precision of the method is not known because
contents of the flask into a dried and weighed evap-
interlaboratory data are not available. A Single pre-
orating dish. If there are anti-bumping granules in
cision Statement is not appropriate because of the
the flask, remove these by filtration. Wash the flask
number of materials involved. However, a precision
three times with 5 ml of the extraction liquid, col-
of about + 5 O/o could be expected.
-
lecting the washings in the evaporating dish.
Dry the extract under the conditions given in
10 Test report
table 1. If no conditions are specified for the material
being tested, place the dish on a water bath and
The test report shall include the following infor-
evaporate the extraction liquid completely; dry the
mation:
dish with the extract in the vacuum oven (4.11) at
40 “C and at a pressure less than or equal to
a) a reference to this International Standard;
3 kPal) until constant mass is reached. Allow the
dish to cool in the desiccator (4.9) to room tem-
b) a comp
...