IEC 61189-2:2006

INTERNATIONAL IEC
STANDARD 61189-2
Second edition
2006-05
Test methods for electrical materials, printed
boards and other interconnection structures
and assemblies –
Part 2:
Test methods for materials
for interconnection structures
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INTERNATIONAL IEC
STANDARD 61189-2
Second edition
2006-05
Test methods for electrical materials, printed
boards and other interconnection structures
and assemblies –
Part 2:
Test methods for materials
for interconnection structures

 IEC 2006  Copyright - all rights reserved
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mechanical, including photocopying and microfilm, without permission in writing from the publisher.
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For price, see current catalogue

– 2 – 61189-2  IEC:2006(E)
CONTENTS
FOREWORD.6
INTRODUCTION.8

1 Scope.9
2 Normative references.9
3 Accuracy, precision and resolution .9
3.1 Accuracy .10
3.2 Precision .10
3.3 Resolution .11
3.4 Report .11
3.5 Student’s "t" distribution.11
3.6 Suggested uncertainty limits .12
4 Catalogue of approved test methods .13
5 P: Preparation/conditioning test methods .13
5.1 Test 2P01: Dry heat (under consideration) .13
5.2 Test 2P02: Solder float stress (under consideration) .13
6 V: Visual test methods .13
7 D: Dimensional test methods .13
7.1 Test 2D01: Thickness of base materials and rigid boards .13
8 C: Chemical test methods .15
8.1 Test 2C01: Resistance to sodium hydroxide of base materials.15
8.2 Test 2C02: Gel time of epoxy based prepreg materials.16
8.3 Test 2C03: Resin content of prepreg materials by treated weight.17
8.4 Test 2C04: Volatile content of prepreg materials .19
8.5 Test 2C05: Blistering during heat shock .21
8.6 Test 2C06: Flammability, vertical burning test for rigid materials .23
8.7 Test 2C07: Flammability; horizontal burning test for rigid materials.26
8.8 Test 2C08: Flammability, flex material .29
8.9 Test 2C09: Melting viscosity of prepreg materials.33
8.10 Test 2C10: Resin content of prepreg materials by sublimation.35
8.11 Test 2C11: UV blocking characteristics of laminates .37
8.12 Test 2C12: Total halogen content in base materials .38
9 M: Mechanical test methods.42
9.1 Test 2M01: Test method for bow and twist .42
9.2 Test 2M02: Bow/twist after etching and heating.43
9.3 Test 2M03: Cure factor of base materials by differential scanning calorimetry
(DSC) or thermomechanical analysis (TMA) .45
9.4 Test 2M04: Twist after heating (under consideration) .46
9.5 Test 2M05: Pull-off strength.46
9.6 Test 2M06: Peel strength after exposure to solvent vapour.48
9.7 Test 2M07: Peel strength after immersion in solvent .50
9.8 Test 2M08: Flexural strength (under consideration).51
9.9 Test 2M09: Resin flow of prepreg material .51
9.10 Test 2M10: Glass transition temperature of base materials by differential
scanning calorimetry (DSC) .53

61189-2  IEC:2006(E) – 3 –
9.11 Test 2M11: Glass transition temperature of base materials by
thermomechanical analysis (TMA) .55
9.12 Test 2M12: Surface waviness .58
9.13 Test 2M13: Peel strength as received .59
9.14 Test 2M14: Peel strength after heat shock .60
9.15 Test 2M15: Peel strength after dry heat.63
9.16 Test 2M16: Peel strength after simulated plating .64
9.17 Test 2M17: Peel strength at high temperature .66
9.18 Test 2M18: Surface quality (under consideration).68
9.19 Test 2M19: Punching (under consideration) .68
9.20 Test 2M20: Flexural strength .68
9.21 Test 2M21: Rolling fatigue of flexible base materials .69
9.22 Test 2M22: Weight of foil after lamination .71
9.23 Test method 2M23: Rectangularity of cut panels .73
9.24 Test 2M24: Coefficient of thermal expansion (under consideration) .74
9.25 Test 2M25: Time to delamination by thermomechanical analysis (TMA).74
9.26 Test 2M26: Scaled flow test for prepreg materials .75
9.27 Test 2M27: The resin flow properties of coverlay films, bonding films and
adhesive cast films used in the fabrication of flexible printed boards .78
10 Electrical test methods.83
10.1 Test 2E01: Surface tracking, moisture condition (under consideration) .83
10.2 Test 10.2 2E02: Dielectric breakdown of base materials parallel to
laminations .83
10.3 Test 2E03: Surface resistance after damp heat, steady state .85
10.4 Test 2E04: Volume resistivity and surface resistivity.90
10.5 Test 2E05: Permittivity and dielectric dissipation (under consideration).94
10.6 Test 2E06: Volume and surface resistivity, 3 electrodes (under consideration).94
10.7 Test 2E07: Surface and volume resistivity, elevated temperature (under
consideration).94
10.8 Test 2E08: Surface corrosion.94
10.9 Test 2E09: Comparative tracking index (CTI) .96
10.10 Test 2E10: Permittivity and dissipation factor (under consideration). 100
10.11 Test 2E11: Electric strength (under consideration) . 100
10.12 Test 2E12: Resistance of foil (under consideration). 100
10.13 Test 2E13: Corrosion at edge (under consideration). 100
10.14 Test 2E14: Arc resistance. 100
10.15 Test 2E15: Dielectric break-down (under consideration) . 104
10.16 Test 2E16: Contact resistance of printed circuit keypad cont (under
consideration). 104
10.17 Test 2E17: Insulation resistance of printed board materials . 104
10.18 Test 2E18: Fungus resistance of printed board materials . 105
11 N: Environmental test methods . 109
11.1 Test 2N01: Pressure cooker test (under consideration) . 109
11.2 Test 2N02: Water absorption . 109
12 X: Miscellaneous test methods. 110
12.1 Test 2X02: Dimensional stability of thin laminates . 110

– 4 – 61189-2  IEC:2006(E)
Annex A (informative) Worked examples . 114
Annex B (informative) Conversion table. 116
Annex C (informative) Laboratory pro forma (form) . 121
Annex D (informative) Laboratory pro forma . 122

Figure 1 – Thickness measuring points.14
Figure 2 – Position of specimens.20
Figure 3 – Fluidized sand bath.22
Figure 4 – Test fixture .28
Figure 5 – V method (Vertical flammability method) .32
Figure 6 – VTM method (vertical flammability method for recaltrant specimens).32
Figure 7 – Example of prepreg melting viscosity .35
Figure 8 – Position of specimens for resin content.36
Figure 9 – Absorption of combustion gas using a combustion flask set-up.40
Figure 10 – Composition of ion exchange chromatograph .40
Figure 11 – Specimen for peel strength measurement .49
Figure 12 – Differential scanning calorimetry .54
Figure 13 – Thermomechanical analysis (expansion mode) .57
Figure 14 – Test specimen pattern .70
Figure 15 – General arrangement of apparatus.70
Figure 16 – Scaled flow test specimen before lamination .77
Figure 17 – Scaled flow test specimen measurement points .77
Figure 18 – Test patterns for clearance filling test.79
Figure 19 – Punched test pattern for squeeze-out test .80
Figure 20 – Standard lay-up of materials in the press to prepare the test specimens for
referee tests .81
Figure 21 – Profiles of press conditions to prepare the test specimens for referee tests .82
Figure 22 – Measurement of volume resistance.89
Figure 23 – Measurement of surface resistance.89
Figure 25 – Electrode connections for measuring volume resistance.93
Figure 26 – Electrode connections for measuring surface resistance .93
Figure 27 – Ring and disk pattern.95
Figure 28 – Comb pattern.96
Figure 31 – Example of test apparatus .98
Figure 32 – Example of test circuit .98
Figure 33 – Arc-resistance test circuit. 101
Figure 34 – Tungsten steel rod electrode assembly . 102
Figure 35 – Test specimen for insulation resistance. 104
Figure 36 – Location of specimens on original sheet for dimensional stability test . 111
Figure 37 – Location of marks on specimen for dimensional stability. 112

61189-2  IEC:2006(E) – 5 –
Table 1 – Student’s "t" distribution.12
Table 2 – Example of analysing conditions for the ion exchange chromatography .41
Table 3 – Specimen dimensions .68
Table 4 – Number of plies per specimen as a function of glass thickness.76
Table 6 – Specimen dimension (cm).86
Table 7 – Test pattern dimensions.91
Table 8 – Arc resistance. 103

– 6 – 61189-2  IEC:2006(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
TEST METHODS FOR ELECTRICAL MATERIALS, PRINTED BOARDS AND
OTHER INTERCONNECTION STRUCTURES AND ASSEMBLIES –

Part 2: Test methods for materials for interconnection structures

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
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with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61189-2 has been prepared by IEC technical committee 91: Surface
mounting technology, in cooperation with technical committee 52: Printed circuits (now
disbanded), and technical committee 50: Environmental testing.
This second edition replaces the first edition, published in 1997, and its Amendment 1 (2000).
It constitutes a technical revision.
The document 91/564/FDIS, circulated to the National Committees as Amendment 2, led to the
publication of this new edition.

61189-2  IEC:2006(E) – 7 –
The text of this standard is based on the first edition, its amendment 1 and on the following
documents:
FDIS Report on voting
91/564/FDIS 91/572/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
The significant technical changes with respect to the previous edition concern the addition of
several new tests in the following categories:
− C: Chemical test methods
− D: Dimensional test methods:
− E: Electrical test methods
− M: Mechanical test methods
− N: Environmental test methods
− X: Miscellaneous test methods
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
This standard forms part of a series and should be used in conjunction with other parts in the
same series, all under the main title Test methods for electrical materials, interconnection
structures and assemblies:
Part 1: General test methods and methodology
Part 2: Test methods for materials for interconnection structures
Part 3: Test methods for interconnection structures (printed boards)
Part 4: Test methods for electronic components assembling characteristics
Part 5: Test methods for printed board assemblies
Part 6: Test methods for materials used in electronic assemblies
It should also be read in conjunction with IEC 60068: Environmental testing.
The committee has decided that the contents of this publication will remain unchanged until the
maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

___________
Under consideration.
– 8 – 61189-2  IEC:2006(E)
INTRODUCTION
IEC 61189 relates to test methods for printed boards and printed board assemblies, as well as
related materials or component robustness, irrespective of their method of manufacture.
The standard is divided into separate parts, covering information for the designer and the test
methodology engineer or technician. Each part has a specific focus; methods are grouped
according to their application and numbered sequentially as they are developed and released.
In some instances test methods developed by other TCs (e.g. TC 50) have been reproduced
from existing IEC standards in order to provide the reader with a comprehensive set of test
methods. When this situation occurs, it will be noted on the specific test method; if the test
method is reproduced with minor revision, those paragraphs that are different are identified.
This part of IEC 61189 contains test methods for materials used to produce interconnection
structures (printed boards) and electronic assemblies. The methods are self-contained, with
sufficient detail and description so as to achieve uniformity and reproducibility in the
procedures and test methodologies.
The tests shown in this standard are grouped according to the following principles:
P: preparation/conditioning methods
V: visual test methods
D: dimensional test methods
C: chemical test methods
M: mechanical test methods
E: electrical test methods
N: environmental test methods
X: miscellaneous test methods
To facilitate reference to the tests, to retain consistency of presentation, and to provide for
future expansion, each test is identified by a number (assigned sequentially) added to the
prefix (group code) letter showing the group to which the test method belongs.
The test method numbers have no significance with respect to an eventual test sequence; that
responsibility rests with the relevant specification that calls for the method being performed.
The relevant specification, in most instances, also describes pass/fail criteria.
The letter and number combinations are for reference purposes, to be used by the relevant
specification. Thus "2D01" represents the first dimensional test method described in this
publication.
In short, for this example, 2 is the part of IEC standard (61189-2), D is the group of methods,
and 01 is the test number.
A list of all test methods included in this standard, as well as those under consideration is given
in Annex B. This annex will be reissued whenever new tests are introduced.

61189-2  IEC:2006(E) – 9 –
TEST METHODS FOR ELECTRICAL MATERIALS, PRINTED BOARDS AND
OTHER INTERCONNECTION STRUCTURES AND ASSEMBLIES –

Part 2: Test methods for materials for interconnection structures

1 Scope
This part of IEC 61189 provides a catalogue of test methods representing methodologies and
procedures that can be applied to test materials used for manufacturing interconnection
structures (printed boards) and assemblies.
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.
IEC 60068-1:1988, Environmental testing – Part 1: General and guidance
IEC 60068-2-2:1974, Environmental testing – Part 2: Tests – Tests B: Dry heat
IEC 60068-2-78:2001, Environmental testing – Part 2-78: Tests – Test Cab: Damp heat, steady
state
IEC 60093:1980, Methods of test for volume resistivity and surface resistivity of solid electrical
insulating materials
IEC 60243-1:1998, Electrical strength of insulating materials – Test methods: Tests at power
frequencies
IEC 61189-3:1997, Test methods for electrical materials, interconnection structures and
assemblies – Part 3: Test methods for interconnection structures (printed boards)
ISO 3274:1996, Geometrical Products Specifications (GPS) – Surface texture: Profile method –
Nominal characteristics of contact (stylus) instruments
ISO 9001:2000, Quality systems – Model for quality assurance in production, installation and
servicing
ANSI/UL-94:1993, Standard for tests for flammability of plastic materials for parts in devices
and appliances, Tests for
3 Accuracy, precision and resolution
Errors and uncertainties are inherent in all measurement processes. The information given
below enables valid estimates of the amount of error and uncertainty to be taken into account.
Test data serve a number of purposes which include:
– monitoring a process;
– enhancing confidence in quality conformance;
– arbitrating between customer and supplier.

– 10 – 61189-2  IEC:2006(E)
In any of these circumstances, it is essential that confidence can be placed upon the test data
in terms of:
– accuracy: calibration of the test instruments and/or system;
– precision: the repeatability and uncertainty of the measurement;
– resolution: the suitability of the instruments and/or system for the test.
3.1 Accuracy
The regime by which routine calibration of the test equipment is undertaken shall be clearly
stated in the quality documentation of the supplier or agency conducting the test, and shall
meet the requirements of ISO 9001:2000.
The calibration shall be conducted by an agency having accreditation to a national or
international measurement standard institute. There should be an uninterrupted chain of
calibration to a national or international standard.
Where calibration to a national or international standard is not possible, round robin techniques
may be used, and documented, to enhance confidence in measurement accuracy.
The calibration interval shall normally be one year. Equipment consistently found to be outside
acceptable limits of accuracy shall be subject to shortened calibration intervals. Equipment
consistently found to be well within acceptable limits may be subject to relaxed calibration
intervals.
A record of the calibration and maintenance history shall be maintained for each instrument.
These records should state the uncertainty of the calibration technique (in ± % deviation) in
order that uncertainties of measurement can be aggregated and determined.
A procedure shall be implemented to resolve any situation where an instrument is found to be
outside calibration limits.
3.2 Precision
The uncertainty budget of any measurement technique is made up of both systematic and
random uncertainties. All estimates shall be based upon a single confidence level, the
minimum being 95 %.
Systematic uncertainties are usually the predominant contributor, and will include all
uncertainties not subject to random fluctuation. These include:
– calibration uncertainties;
– errors due to the use of an instrument under conditions which differ from those under which
it was calibrated;
– errors in the graduation of a scale of an analogue meter (scale shape error).
Random uncertainties result from numerous sources but can be deduced from repeated
measurement of a standard item. Therefore, it is not necessary to isolate the individual
contributions. These may include:
– random fluctuations such as those due to the variation of an influence parameter. Typically,
changes in atmospheric conditions reduce the repeatability of a measurement;
– uncertainty in discrimination, such as setting a pointer to a fiducial mark, or interpolating
between graduations on an analogue scale.

61189-2  IEC:2006(E) – 11 –
Aggregation of uncertainties: Geometric addition (root-sum-square) of uncertainties may be
used in most cases. Interpolation error is normally added separately and may be accepted as
being 20 % of the difference between the finest graduations of the scale of the instrument.
2 2
U = ± (U + U ) + U
t s r i
where
U is the total uncertainty
t
U is the systematic uncertainty
s
U is the random uncertainty
r
U is the interpolation error
i
Determination of random uncertainties: Random uncertainty can be determined by repeated
measurement of a parameter, and subsequent statistical manipulation of the measured data.
The technique assumes that the data exhibits a normal (Gaussian) distribution.
t ×σ
U =
r
n
where
U is random uncertainty
r
n is the sample size
t is the percentage point of the “t” distribution (from 3.5), statistical tables
σ is the standard deviation (σ )
n-1
3.3 Resolution
It is paramount that the test equipment used is capable of sufficient resolution. Measurement
systems used should be capable of resolving 10 % (or better) of the test limit tolerance.
It is accepted that some technologies will place a physical limitation upon resolution (e.g.
optical resolution)
3.4 Report
In addition to requirements detailed in the test specification, the report shall detail:
– the test method number and revision;
– the identity of the sample(s);
– the test instrumentation;
– the specified limit(s);
– an estimate of measurement uncertainty, and resultant working limit(s) for the test;
– the detailed test results;
– the test date, and operators’ signature.
3.5 Student’s "t" distribution
Table 1 gives values of the factor "t" for 95 % and 99 % confidence levels, as a function of the
number of measurements. It is sufficient to use 95 % limits, as in the case of the worked
examples shown in Annex A.
– 12 – 61189-2  IEC:2006(E)
Table 1 – Student’s "t" distribution
Sample t value t value Sample t value t value
size 95 % 99 % size 95 % 99 %
2 12,7 63,7  14 2,16 3,01
3 4,3 9,92  15 2,14 2,98
4 3,18 5,84  16 2,13 2,95
5 2,78 4,6  17 2,12 2,92
6 2,57 4,03  18 2,11 2,9
7 2,45 3,71  19 2,1 2,88
8 2,36 3,5  20 2,09 2,86
9 2,31 3,36  21 2,08 2,83
10 2,26 3,25  22 2,075 2,82
11 2,23 3,17  23 2,07 2,81
12 2,2 3,11  24 2,065 2,8
13 2,18 3,05  25 2,06 2,79

3.6 Suggested uncertainty limits
The following target uncertainties are suggested:
a) Voltage < 1 kV: ± 1,5 %
b) Voltage > 1 kV: ± 2,5 %
c) Current < 20 A: ± 1,5 %
d) Current > 20 A: ± 2,5 %
Resistance
e) Earth and continuity: ± 10 %
f) Insulation: ± 10 %
g) Frequency: ± 0,2 %
Time
± 1 s
h) Interval < 60 s:
i) Interval > 60 s: ± 2 %
j) Mass < 10 g: ± 0,5 %
k) Mass 10 g to 100 g: ± 1 %
l) Mass > 100 g: ± 2 %
m) Force: ± 2 %
n) Dimension < 25 mm: ± 0,5 %
o) Dimension > 25 mm: ± 0,1 mm
p) Temperature < 100 °C: ± 1,5 %
q) Temperature > 100 °C: ± 3,5 %
r) Humidity 30 to 75 % RH: ± 5 % RH
Plating thicknesses
s) Backscatter method: ± 10 %
t) Microsection: ± 2 µm
u) Ionic contamination: ± 10 %

61189-2  IEC:2006(E) – 13 –
4 Catalogue of approved test methods
This standard provides specific test methods in complete detail to permit implementation with
minimal cross-referencing to other specific procedures. The use of generic conditioning
exposures is accomplished in the methods by reference, for example IEC 61189-1 and
IEC 60068, and when applicable, is a mandatory part of the test method standard.
Each method has its own title, number and revision status to accommodate updating and
improving the methods as industry requirements change or demand new methodology. The
methods are organized in test method groups and individual tests.
5 P: Preparation/conditioning test methods
5.1 Test 2P01: Dry heat (under consideration)
5.2 Test 2P02: Solder float stress (under consideration)
6 V: Visual test methods
7 D: Dimensional test methods
7.1 Test 2D01: Thickness of base materials and rigid boards
7.1.1 Object
This test method covers the procedure for the determination of the thickness of base materials,
clad or unclad.
7.1.2 Test specimens
Standard sheet sizes of metal-clad or unclad base materials.
Standard panel sizes of metal-clad or unclad base materials.
7.1.3 Test apparatus and material
A suitable micrometer having a resolution of 0,01 mm or better shall be used.
7.1.4 Procedure
a) General conditions
– Test specimens shall be placed between the two faces of the micrometer, so that the
whole face of the pressure-foot will fall within the area of the material. The pressure-foot
shall be lowered gently, slowly and with great care onto the test specimen so that all
punching effect is avoided.
– No stress shall be imposed by hand on the instrument or the material when a reading is
being taken. The reading shall be taken as soon as the pointer has ceased to move. It
is necessary to take care in avoiding parallax errors and vibrations which may
significantly affect the results.
b) Method 1
– This procedure is intended for the thickness measurement of the sheets of metal-clad
or unclad base materials.
– The specimen shall be held vertically or horizontally.

– 14 – 61189-2  IEC:2006(E)
– Thickness to the nearest 0,01 mm at two points 25 mm or more inside each edge, at
eight points, and additionally at two points in the middle parts, so that a total of
10 points, shall be measured as shown in Figure 1.
– The measurement shall be made twice at each point and the mean value shall be
determined as the thickness of each point.
– For automatic thickness inspection, continuous measuring shall be performed in three
measuring tracks parallel to the longitudinal axis of the sheet, two at least 25 mm from
the longitudinal edges and the third near the midline.
25 min.
Measuring
points
25 min.
IEC  1890/99
Figure 1 – Thickness measuring points
c) Method 2
– This procedure is intended for the thickness measurement of panels of metal-clad or
unclad base materials. The thickness of the specimens held vertically or horizontally
shall be measured at the places which are agreed between the interested parties.
7.1.5 Report
The report shall include:
a) the test method number and revision;
b) the date of the test;
c) the identification of the material tested;
d) a statement certifying that the test was carried out for as-received metal-clad or unclad
base materials;
e) the thicknesses measured and the nominal thickness with its tolerance;
f) any deviation from this test method;
g) the name of the person conducting the test.
7.1.6 Additional information
The use of a micrometer with a damping device, or controlled rate of movement of the
pressure-foot, is advantageous.

61189-2  IEC:2006(E) – 15 –
8 C: Chemical test methods
8.1 Test 2C01: Resistance to sodium hydroxide of base materials
8.1.1 Object
The purpose of this test method is to provide a procedure for determining the alkaline
resistance of base materials by exposure to a sodium hydroxide solution.
8.1.2 Test specimens
a) Specimens shall be taken from the panel or sheet in such a way that they are at least
25 mm from the edge of the sheet.
b) Specimens shall be prepared from a sample of metal-clad base material from which the
metal has been completely removed by any appropriate method reflecting usual practice.
c) Specimen size is (50 ± 2) mm in both length and width, and shall be cut out using a fine
saw to give the edges a smooth finish.
d) A minimum of three specimens shall be used.
8.1.3 Test apparatus and materials
The following test apparatus and materials shall be used:
a) an appropriate alkaline-proof container which contains an analytical grade sodium
hydroxide solution maintained at a temperature of (40 ± 2) °C at a concentration by weight
of (3 ± 0,2) %. In order to ensure that the concentration remains within the tolerance, the
solution must be prepared daily. The number of specimens tested per litre of solution shall
not be more than 50;
b) a rack to hold specimens upright in the container. The design of the rack shall allow
maximum exposure of the specimen surfaces to the solution;
c) a clean dry gauze, cloth or paper to wipe off the water from the specimen surfaces;
d) a fine blade saw for the sample preparation.
8.1.4 Procedure
Place the specimens in the rack then in the sodium hydroxide solution for 3 min ± 20 s.
Take the rack out of the sodium hydroxide solution and quickly rinse the specimens under
running water for a minimum of 5 min.
Wipe the water from the specimen surfaces completely with a clean dry gauze, cloth or paper.
Immediately make a visual check for colour change, swelling, blistering and/or delamination.
8.1.5 Report
The report shall include:
a) the test number and revision index;
b) the testing date;
c) the identification of the material tested;
d) the changes in surface appearance, if any;
e) any deviation from this test method.

– 16 – 61189-2  IEC:2006(E)
8.1.6 Additional information
Sodium hydroxide is a powerful alkaline chemical. It shall be handled with care, avoiding eye
and skin contact by wearing protective glasses and chemically resistant gloves.
8.2 Test 2C02: Gel time of epoxy based prepreg materials
8.2.1 Object
The purpose of this test method is to provide a means for determining the gel time of epoxide
resin impregnated reinforcement cured to the B-stage used in the manufacturing of laminate
and printed boards.
8.2.2 Test specimens
A number of pieces approximately 100 mm square or another convenient size, in order to yield
approximately 1 g of dry resin, shall be cut from areas uniformly distributed across the width of
the sheet or roll, but excluding the area within 25 mm of each edge or selvage.
8.2.3 Test apparatus and material
The following test apparatus and materials shall be used:
a) heating plate capable of maintaining a temperature of (170 ± 0,5) °C;
b) timer, capable of determining time within ± 1 s;
c) wooden stick, pointed, approximately 3 mm in diameter;
d) a measure of capacity for 0,3 g to 0,4 g resin powder;
e) sieve, 50 mesh per inch.
8.2.4 Procedure
Detach the dry resin from the prepreg (B-stage) by folding or crushing. Remove any glass fibre
present by sieving alternatively, in the case of materials too soft to detach dry resin by crushing,
the resin required may be obtained by pressing the folded stack of material in contact with the
heating plate and squeezing out the melted resin.
Remove any glass fibre present by sieving.
Adjust the heating plate or equivalent to 170 °C and allow to stabilize at that temperature.
Using the measure of capacity a quantity of 0,3 g to 0,4 g resin powder shall be taken.
Pour the measured dry resin in the form of a small cone on one spot of the heating plate and
start the timer immediately. If the alternative method given above is used, the timer shall be
started at that moment when the folded stack is brought in contact with the heating plate.
Stir the resin, using a wooden stick approximately 3 mm in diameter, holding the stick as near
vertical as possible and mixing the centre as well as the edges of the melted resin. While
stirring, the diameter of the pool of melting resin shall not exceed 25 mm.
At the approach of the gel point the resin becomes tacky and forms strings when pulling the
stick out. The gel point is reached when it no longer forms strings when pulling the stick out,
and is no longer tacky but still elastic. At this point, the timer is stopped and the elapsed time
measured in seconds is taken as the gel time. When used as a reference, three separate
measurements shall be carried out and the average recorded as gel time.

61189-2  IEC:2006(E) – 17 –
8.2.5 Report
The report shall include:
a) the test method number and revision index;
b) the testing date;
c) the identification of the material tested;
d) the gel time in seconds (average);
e) any deviation from this test method.
8.2.6 Additional information
The determination of gel time may also be carried
...