ASTM D176-96
(Test Method)Standard Test Methods for Solid Filling and Treating Compounds Used for Electrical Insulation
Standard Test Methods for Solid Filling and Treating Compounds Used for Electrical Insulation
SCOPE
1.1 These test methods cover physical and electrical tests for solid filling and treating compounds used for electrical insulation which are fusible to a liquid without significant chemical reaction. Compounds that are converted to the solid state by polymerization, condensation, or other chemical reaction are not included in these test methods.
1.2 These test methods are designed primarily for asphaltic or bituminous compounds, waxes, and fusible resins, or mixtures thereof, although some of these methods are applicable to semisolid types such as petrolatums. Special methods more suitable for hydrocarbon waxes are contained in Test Methods D1168.
1.3 Adequate ventilation must be provided when these tests involve heating.
1.4 The test methods appear in the following sections:Test MethodSectionsElectrical Tests:A-C Loss Characteristics and Permittivity (Dielectric Constant)51-54 Dielectric Strength42-45Volume Resistivity-Temperature Characteristics46-49Physical Tests:Coefficient of Expansion or Contraction22-41Flash and Fire Points9 and 10Loss on Heating11 and 12Melting Point5 and 6Penetration15 and 16Softening Point7 and 8Specific Gravity17-21Viscosity13 and 14
1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Note 4 and Note 7.
Note 1--There is no similar or equivalent IEC or ISO standard.
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Designation: D 176 – 96 An American National Standard
Standard Test Methods for
Solid Filling and Treating Compounds Used for Electrical
Insulation
This standard is issued under the fixed designation D 176; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 These test methods cover physical and electrical tests 2.1 ASTM Standards:
for solid filling and treating compounds used for electrical D 5 Test Method for Penetration of Bituminous Materials
insulation which are fusible to a liquid without significant D 6 Test Method for Loss on Heating of Oil and Asphaltic
chemical reaction. Compounds that are converted to the solid Compounds
state by polymerization, condensation, or other chemical reac- D 70 Test Method for Specific Gravity of Semi-Solid Bitu-
tion are not included in these test methods. minous Materials
1.2 These test methods are designed primarily for asphaltic D 71 Test Method for Relative Density of Solid Pitch and
or bituminous compounds, waxes, and fusible resins, or mix- Asphalt (Displacement Method)
tures thereof, although some of these methods are applicable to D 88 Test Method for Saybolt Viscosity
semisolid types such as petrolatums. Special methods more D 92 Test Method for Flash and Fire Points by Cleveland
suitable for hydrocarbon waxes are contained in Test Methods Open Cup
D 1168. D 127 Test Method for Drop Melting Point of Petroleum
1.3 Adequate ventilation must be provided when these tests Wax, Including Petrolatum
involve heating. D 149 Test Method for Dielectric Breakdown Voltage and
1.4 The test methods appear in the following sections: Dielectric Strength of Solid Electrical Insulating Materials
at Commercial Power Frequencies
Test Method Sections
D 150 Test Methods for AC Loss Characteristics and Per-
Electrical Tests: 42-54
mittivity (Dielectric Constant) of Solid Electrical Insulat-
A-C Loss Characteristics and Permittivity (Dielectric Constant) 51-54
ing Materials
Dielectric Strength 42-45
Volume Resistivity-Temperature Characteristics 46-49
D 257 Test Methods for D-C Resistance or Conductance of
Physical Tests: 5-41
Insulating Materials
Coefficient of Expansion or Contraction 22-41
Flash and Fire Points 9 and 10 D 937 Test Method for Cone Penetration of Petrolatum
Loss on Heating 11 and 12
D 1168 Test Methods for Hydrocarbon Waxes Used for
Melting Point 5 and 6
Electrical Insulation
Penetration 15 and 16
E 28 Test Method for Softening Point by Ring-and-Ball
Softening Point 7 and 8
Specific Gravity 17-21
Apparatus
Viscosity 13 and 14
E 102 Test Method for Saybolt Furol Viscosity of Bitumi-
1.5 The values stated in SI units are to be regarded as the
nous Materials at High Temperatures
standard. The values given in parentheses are for information
3. Terminology
only.
1.6 This standard does not purport to address all of the 3.1 Definitions:
safety concerns, if any, associated with its use. It is the
3.1.1 dielectric strength, n—the voltage gradient at which
responsibility of the user of this standard to establish appro- dielectric failure of the insulating material occurs under spe-
priate safety and health practices and determine the applica-
cific conditions of test.
bility of regulatory limitations prior to use. For specific hazard 3.2 Definitions of Terms Specific to This Standard:
statements, see Note 3 and Note 6.
3.2.1 loss on heating, n— of filling or treating compound,
the change in weight of a compound when heated under
These methods of testing are under the jurisdiction of ASTM Committee D-9
on Electrical and Electronic Insulating Materials and are the direct responsibility of Annual Book of ASTM Standards, Vol 04.03.
Subcommittee D09.01 on Electrical Insulating Varnishes, Powders, and Encapsu- Annual Book of ASTM Standards, Vol 04.04.
lating Compounds. Annual Book of ASTM Standards, Vol 05.01.
Current edition approved March 10, 1996. Published May 1996. Originally Annual Book of ASTM Standards, Vol 10.01.
published as D 176 – 23 T. Last previous edition D 176 – 91. Annual Book of ASTM Standards, Vol 06.03.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 176
prescribed conditions at a standard temperature for a specified the material is shipped in pails or drums, a sample may be
time. removed with a clean knife, hatchet, auger or other cutting tool,
3.2.2 melting point, n— of filling or treating compound, the
discarding the top 50 or 75 mm (2 or 3 in.) of the compound.
temperature at which the compound becomes sufficiently fluid
Melting of the compound should be avoided unless it can be
to drop from the thermometer used in making the determina-
poured directly into the testing container. A melting and
tion under prescribed conditions.
pouring temperature of 50°C (90°F) above the softening point
3.2.3 penetration, n— of filling or treating compound, the
is recommended for filling testing containers with asphaltic
distance traveled by a standard needle (or cone) as it pierces a
compounds. Take care not to overheat the compound nor to
specimen under specified conditions of load, time and tempera-
entrap air.
ture.
4.2 With certain materials that tend to entrap gasses due to
3.2.4 softening point, n— of filling or treating compound,
high viscosity at pouring temperatures, or to froth on heating,
the temperature at which the central portion of a disk of the
it may be necessary to degas the material prior to testing in
compound held within a horizontal ring of specified dimen-
order that consistent results may be secured (unless the
sions has sagged or flowed downward a distance of 25.4 mm (1
3 particular test includes such procedure). If degassing is re-
in.) under the weight of a 9.5-mm ( ⁄8-in.) diameter steel ball as
quired, it shall be performed by heating the material in a
the sample is heated at a prescribed rate in a water or glycerin
vacuum oven. The temperature and vacuum shall be high
bath.
enough, and the time long enough to ensure driving off the
4. Sampling and Conditioning
mechanically entrapped gasses, but should tend to decompose
4.1 Due to the diverse nature of the compounds and the as little as possible. A temperature 50°C (90°F) higher than the
various forms and packages commercially available, no stan-
softening point of the compound, an absolute pressure of 6.9 to
dard methods of sampling have been established. When the
20.7 kPa (1 to 3 psi), and a time of 30 to 45 min are
sample is in the form of cakes or ingots, a representative
recommended for asphaltic compounds. The sample shall then
sample may usually be secured by breaking or cutting a
be poured into the testing container.
transverse section from the middle of the cake or ingot. When
PHYSICAL TESTS
MELTING POINT FLASH AND FIRE POINTS
5. Significance and Use
9. Significance and Use
5.1 The melting point is useful in selecting a filling or
9.1 The flash and fire points must be high enough so that the
treating compound that will not flow at the operating tempera-
possibility of an explosion or fire is at a minimum when the
ture of the device in which it will be used. It is also essential
compounds are being heated and poured. A flash point at least
that it shall not be so high as to injure the insulation at the time
35°C (63°F) above the pouring temperature is usually consid-
of pouring. This test method may be used for specification,
ered necessary for safe operations. An unusually low flash
classification, and for control of product uniformity.
point for a given compound indicates a mixture or contamina-
6. Procedure
tion with a volatile material. This test method is useful for
purposes of specification, classification, and control of product
6.1 Determine the melting point of petrolatums, waxes, and
similar compounds of a relatively sharp melting point by Test uniformity.
Method D 127.
10. Procedure
NOTE 1—This method should not be used for asphalts and other types
10.1 Determine the flash and fire points of all compounds in
with a prolonged melting range.
accordance with Test Method D 92.
SOFTENING POINT
10.2 In the case of certain compounds containing chlorine,
the flash may be indefinite and no fire point may exist. Report
7. Significance and Use
this fact.
7.1 The softening point is useful in selecting a filling or
treating compound that will not flow at the operating tempera-
LOSS ON HEATING
ture of the device in which it is used. It is also an indication of
the pouring temperature, which should not be so high as to
11. Significance and Use
injure the insulation of a device. This test method is used, when
11.1 Loss on heating includes loss of moisture and volatile
the compound has no definite melting point, for purposes of
constituents less any weight gain due to oxidization. It is useful
specification, classification, and control of product uniformity.
for control of product uniformity and as an indication of pot or
8. Procedure
tank life if the test is performed at the appropriate temperature.
8.1 Determine the softening point in accordance with Test This test method shall not be used to compare compounds of
Method E 28. different basic chemical compositions.
D 176
12. Procedure
Weight, g Time, s
12.1 Determine the loss on heating of asphaltic and certain
At 25°C (77°F) 100 5
other types of compounds by Test Method D 6.
Other standard conditions are:
NOTE 2—The reproducibility of this test method may be poor due to
Weight, g Time, s
insufficient control of the air circulation over the specimens and to weight
gain from oxidation of some compounds. With certain compounds it may
At 0°C (32°F) 200 60
At 46°C (115°F) 50 5
be desirable to conduct the test at a lower temperature than the specified
temperature of 163°C (325.4°F).
16.2 For very soft materials, such as petrolatums, use Test
NOTE 3—Caution: When compounds of low flash point and high
Method D 937.
volatility are tested, the oven shall have low-temperature heating elements
and a safety door latch to relieve pressure in case of an explosion.
SPECIFIC GRAVITY
VISCOSITY
17. Significance and Use
13. Significance and Use
17.1 Specific gravity is useful for indicating product unifor-
mity and for calculating the weight of a given volume of
13.1 The Saybolt viscosity is nearly proportional to the
kinematic viscosity of filling and treating compounds and material. In some instances it is useful in estimating the amount
hence, it is an indication of whether or not the material will of mineral fillers in a compound. If specific gravity is known at
flow readily under its own weight at a prescribed temperature. several temperatures, the coefficient of expansion may be
It is also satisfactory for control of product uniformity and for calculated. If the specific gravity of a compound is determined
specification purposes. before and after degassing, the volume of entrapped gasses
may be calculated.
14. Procedure
17.2 Displacement tests are used to determine the specific
14.1 For waves, petrolatums, and other low-viscosity-type gravity of both untreated and degassed compounds. Conven-
compounds determine the viscosity as Saybolt Universal vis-
tional methods are used for the solid state, and plummet
cosity by Test Method D 88. The standard temperatures for displacement for the liquid state. The values obtained may then
testing are: 21, 38, 54, or 99°C (70, 100, 130, or 210°F). be used to compute the approximate coefficient of cubical
14.2 For asphaltic and other high-viscosity compounds, expansion by Test Method C (see Sections 34-36).
determine the Saybolt Furol viscosity. The standard tempera-
WATER DISPLACEMENT METHODS
tures for testing Furol viscosity are: 25, 38, 50, 60, 82, and
99°C (77, 100, 122, 140, 180, 210°F).
18. Procedure
14.3 For higher temperatures, special techniques and ther-
18.1 Determine the specific gravity by Test Method D 71 or
mometers are required. The standard temperatures are 121,
Test Method D 70.
149, 177, 204, and 232°C (250, 300, 350, 400, 450°F). In these
cases determine the viscosity by Test Method E 102.
PLUMMET DISPLACEMENT METHOD
NOTE 4—For testing waxes and petrolatums, the standard temperature
for comparison purposes is 99°C (210°F), and Saybolt Universal viscosity 19. Scope
is used. For estimation of the properties of asphaltic and other compounds
19.1 The specific gravity of the material at the desired
of high viscosity, it is desirable to measure the viscosity at a number of
temperature is calculated from the weight of the compound
standard temperatures above the softening point. A curve may be plotted
displaced by a calibrated aluminum plummet.
on log-log paper and the temperature at which the Saybolt Furol viscosity
is 470 s may be determined. This viscosity corresponds approximately to
20. Apparatus
a kinematic viscosity of 1000 centistokes, and is a viscosity at which the
compound may conveniently be poured from the container. With potting
20.1 Balance—An analytical balance equipped with pan
compounds, it is also desirable to know the temperature at which the
straddle.
Saybolt Furol viscosity is 100 s, since this viscosity is low enough for
20.2 Plummet—An aluminum plummet of suitable shape
production potting operations.
weighing 5 to 10 g.
20.3 Beaker—A 400-mL heat-resistant glass beaker
PENETRATION
wrapped with a suitable thermal insulation.
15. Significance and Use
20.4 Thermometer—A thermometer of suitable range.
20.5 Wire—Two pieces of fine copper wire.
15.1 Penetration is an indication of the softness or indent-
ability of a compound. Penetration values are used as a basis
21. Procedure
for classification, specification, and control of product unifor-
21.1 Calibration of Plummet—Make the following weight
mity.
determinations of the plummet to the nearest 1 mg as follows:
16. Procedure
a 2 b 5 weight of water displacement in grams at 25°C ~77°F!
16.1 Determine penetration in accordance with Test Method (1)
D 5. This test method is applicable to all compounds except
where:
very soft materials and petrolatums. Unless specified other-
a 5 weight in air, g, and
wise, the standard conditions of test are:
D 176
TEST METHOD A—USING GLASS FLASK
b 5 weight suspended in water, g, at 25°C (77°F).
21.2 Correct the value of the plummet displacement (D )in
tp
24. Apparatus
terms of grams of water at 25°C (77°F) to the pouring
24.1 Flask—A glass flask holding approximately 250 mL
temperature, t , in degrees Celsius, by means of the following
p
to the zero mark, and graduate
...
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