IEC 61234-2:1997 pdf download.Electrical insulating materials – Methods of test for the hydrolytic stability
1 Scope
This part of IEC 61 234 describes the test method for the determination of the hydrolytic stability
of moulded thermosets made of room temperature or oven-curing reaction resins when
subjected to the simultaneous influence of water and high temperature. With this test method,
the irreversible change of mechanical and electrical properties is measured, but no mechanical
stress is imposed on the test specimens.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 61 234. At the time of publication, the editions indicated
were valid. All normative documents are subject to revision, and parties to agreement based on
this part of IEC 61 234 are encouraged to investigate the possibility of applying the most recent
editions of the normative documents indicated below. Members of IEC and ISO maintain
registers of currently valid International Standards.
IEC 60212:1 971 , Standard conditions for use prior to and during the testing of solid
electrical insulating materials
IEC 60250:1 969, Recommended methods for the determination of the permittivity and
dielectric dissipation factor of electrical insulating materials at power, audio and radio
frequencies including metre wavelength
IEC 60455-2:1 977, Specification for solventless polymerisable resinous compounds used for
electrical insulation – Part 2: Methods of test
IEC 60584-1 :1 995, Thermocouples – Part 1 : Reference tables
IEC 60584-2:1 982, Thermocouples – Part 2: Tolerances
Amendment 1 (1 989)
ISO 527-2:1 993, Plastics – Determination of tensile properties – Part 2: Test conditions for
moulding and extrusion plastics
3 Properties to be measured
Changes in the electrical and mechanical properties are determined in accordance with the
International Standards specified below.
3.1 dielectric dissipation factor and permittivity
See clause 37 of IEC 60455-2 which refers to IEC 60250.
3.2 tensile strength
Tensile strength of the specimen is measured in accordance with ISO 527-2.
4 Test specimens
4.1 Dissipation factor and permittivity
The dimensions of the test specimens for the evaluation of dissipation factor retention versus
temperature shall be (1 00 1 ) mm (1 00 1 ) mm (1 0,1 ) mm. The same test specimens
shall be measured prior and after the immersion test (clause 7) for each temperature/time
combination used.
If the preparation of test specimens of 1 mm thickness is not possible (due to high viscosity or
high filling rate of the reaction resin), test specimens of 3 mm ± 0,1 mm shall be used.
4.2 Tensile strength
At least three individual test specimens shall be tested for each property evaluated at each test
temperature and time. For the determination of the properties of the untreated moulded
thermosets 1 0 test specimens shall be used. Unless otherwise specified, the dimensions for
the test specimens shall be in accordance with type 1 B of ISO 527-2.
5 Conditioning
Test specimens prepared from room-temperature curing reaction resins shall be stored 24 h at
room temperature in accordance with IEC 6021 2 and finally cured for 24 h at 80 °C.
The test specimens prepared from oven-curing reaction resins shall be conditioned according
to the manufacturer’s recommendation in order to obtain well cured specimens. The test
specimens shall be tested immediately after oven curing and conditioning at room temperature
or stored in a desiccator prior to testing. After the bath immersion, the test specimens shall be
dried at 60 °C ± 2 K for 48 h at an absolute pressure of less than 1 00 Pa and then stored at
room temperature for a minimum of 8 h in a desiccator prior to further testing.
6 Apparatus
6.1 Ageing vessel
The ageing vessel shall have a minimum volume of 5 l.
For pressure vessels, not more than 5 % water loss is permissible after 1 000 h at the test
temperature. The material of the ageing vessel shall be chosen so that the ageing vessel is
able to satisfy the following calibration inertness test. Demineralized water according to 7.2 is
heated at the highest test temperature 1 40 °C ± 2 K for 1 000 h. The pH of the water as
measured after the inertness test shall not change from 7,0 ± 0,5 to more than 7,0 ± 1 ,5
and the conductivity shall not extend beyond the range of 500S/m to 1 000S/m.
Specimens prepared from room-temperature curing reaction resins can be aged in a glass
container covered with aluminium foil.
NOTE – National codes and regulations for the use of pressure vessels should be observed.
IEC 61234-2:1997 pdf download
