ASTM D2148-02(2008)e1
(Test Method)Standard Test Methods for Bondable Silicone Rubber Tapes Used for Electrical Insulation
Standard Test Methods for Bondable Silicone Rubber Tapes Used for Electrical Insulation
SIGNIFICANCE AND USE
Self-adhesion is a primary initial property since it affects layer-to-layer bonding. The integrity of the bond can significantly affect the electrical and physical performance of the insulation system. Therefore, the degree of self-adhesion is directly related to apparatus performance.
A high degree of self-adhesion is desirable for most electrical applications. In this test, a short unwinding length indicates a high degree of self-adhesion.
This test method has been found useful as a quality control test for lot acceptance.
SCOPE
1.1 These test methods cover tests for bondable silicone rubber tapes which form a sealed structure either with the application of heat (and pressure if needed) or by the process of auto-adhesion (self-fusing).
1.2 The methods appear in the following sections:
Test MethodSection Adhesion3-9 Bond Strength10-17 Dielectric Breakdown Voltage18-25 Hardness 40 Length32 and 33 Thickness 26-31 Width35-39
1.3 The values stated in inch-pound units are to be regarded as standard, except for °C. The values in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.4 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 a specific hazard statement see 22.1.1.
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´1
Designation: D2148 − 02(Reapproved 2008) An American National Standard
Standard Test Methods for
Bondable Silicone Rubber Tapes Used for Electrical
Insulation
This standard is issued under the fixed designation D2148; 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 (´) indicates an editorial change since the last revision or reapproval.
´ NOTE—The units statement in subsection 1.3 was corrected editorially in July 2008.
1. Scope D374 Test Methods for Thickness of Solid Electrical Insu-
lation
1.1 These test methods cover tests for bondable silicone
D1000 Test Methods for Pressure-Sensitive Adhesive-
rubber tapes which form a sealed structure either with the
Coated Tapes Used for Electrical and Electronic Applica-
application of heat (and pressure if needed) or by the process
tions
of auto-adhesion (self-fusing).
D1458 Test Methods for Fully Cured Silicone Rubber-
1.2 The methods appear in the following sections:
Coated Glass Fabric and Tapes for Electrical Insulation
Test Method Section
D2240 Test Method for Rubber Property—Durometer Hard-
ness
Adhesion 3-9
D6054 Practice for Conditioning Electrical Insulating Mate-
Bond Strength 10-17
Dielectric Breakdown Voltage 18-25
rials for Testing
Hardness 40
2.2 ASTM Adjuncts:
Length 32 and 33
Thickness 26-31 Tack tester (one drawing)
Width 35-39
ADHESION
1.3 The values stated in inch-pound units are to be regarded
as standard, except for °C. The values in parentheses are
3. Scope
mathematical conversions to SI units that are provided for
information only and are not considered standard.
3.1 This test method covers the determination of the self-
adhesion of unsupported, self-fusing silicone rubber rectangu-
1.4 This standard does not purport to address all of the
lar and taper-edge (Note 1) tape designed for use as electrical
safety concerns, if any, associated with its use. It is the
insulation.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
NOTE 1—Taper-edge tape includes such cross sections as triangular,
bility of regulatory limitations prior to use. For a specific lens, etc.
hazard statement see 22.1.1.
4. Significance and Use
2. Referenced Documents
4.1 Self-adhesionisaprimaryinitialpropertysinceitaffects
2.1 ASTM Standards:
layer-to-layer bonding. The integrity of the bond can signifi-
D149 Test Method for Dielectric Breakdown Voltage and
cantly affect the electrical and physical performance of the
Dielectric Strength of Solid Electrical Insulating Materials
insulation system. Therefore, the degree of self-adhesion is
at Commercial Power Frequencies
directly related to apparatus performance.
4.2 A high degree of self-adhesion is desirable for most
These methods are under the jurisdiction of ASTM Committee D09 on electrical applications. In this test, a short unwinding length
Electrical and Electronic Insulating Materials and are the direct responsibility of
indicates a high degree of self-adhesion.
Subcommittee D09.07 on Flexible and Rigid Insulating Materials.
CurrenteditionapprovedMay1,2008.PublishedJuly2008.Originallyapproved
4.3 This test method has been found useful as a quality
´1
in 1963. Last previous edition approved in 2002 as D2148 – 02 . DOI: 10.1520/
control test for lot acceptance.
D2148-02R08E01.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from ASTM International Headquarters. Order Adjunct No.
the ASTM website. ADJD2148. Original adjunct produced in 1965.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
D2148 − 02 (2008)
TABLE 1 Suggested Winding Weights For 1-in. Wide Tapes
5. Apparatus
NOTE 1—Winding weights are based on cross-sectional area and have
5.1 Inclined Mandrel Tack Test Fixture— A suggested fix-
been selected to produce approximately the same unit stress on all
ture is shown in Fig. 1. The mandrel shall consist of a ⁄8-in.
cross-sections. For tapes of dimensions not listed, use a winding weight of
(15.9-mm) diameter aluminum rod mounted in low-friction
2 2
approximately 10.5 oz (300 g)/0.01 in. (6.3 mm )
bearings. Good alignment of bearings is necessary for accurate
Tape Thickness, in. (mm)
Weight, oz (g)
results.Whenproperlyassembled,themandrelshallturnfreely
Triangular Rectangular
when loaded with a 1-oz (30-g) weight suspended from a
0.020 (0.51) 0.010 (0.25) 10.5 (300)
cotton thread wound in a single layer at the center of the
0.030 (0.76) 0.015 (0.38) 15.8 (450)
mandrel. 0.040 (1.02) 0.020 (0.51) 21.0 (600)
0.050 (1.27) 0.025 (0.64) 26.4 (750)
5.2 Weights, as specified in Section 7 and means for
0.060 (1.52) 0.030 (0.76) 31.7 (900)
0.070 (1.78) . 37.0 (1050)
attachment.
0.080 (2.03) . 42.3 (1200)
6. Test Specimen
6.1 Atest specimen shall consist of two pieces of tape 12 to
(Note2).Attachtheweighttothefreeendofthetapebymeans
15 in. (300 to 380 mm) long. Divisions spaced 1 in. (25.4 mm)
of a bulldog paper clamp or other suitable device. Release the
apart shall be marked off on one piece of tape. If tapes contain
weight and record the length of tape unwound in 3 min.
an interliner, the interliner shall be removed just prior to
Although the original 1-in. dimensions will elongate due to the
wrapping the mandrel. Dirt and other forms of contamination
unwind weight, consider each division as one unit. While the
shall be avoided.
winding weights are not critical, the use of proper unwinding
7. Procedure
weights is mandatory. Consistent and comparable results de-
pend upon accurate width measurements and the use of the
7.1 Winding—Half lap the unmarked specimen perfectly on
proper unwinding weight.
the mandrel of the test fixture, using the suggested weight as
showninTable1.Theseweightsarenotcritical.However,they 1
NOTE 2—Commercial tapes are usually made to a 6 ⁄16-in. (61.59-
are necessary to get intimate contact and conformability of the
mm) tolerance. Therefore a 600-g weight shall be used for tapes varying
15 1
in width from ⁄16 to 1 ⁄16 in. (23.8 to 27 mm); a 750-g weight shall be
tape. To obtain perfect half lapping, tilt the tack tester at an
3 5
usedfortapesvaryinginwidthfrom1 ⁄16to1 ⁄16in.(30.2to33.3mm)and
appropriate angle as shown in Fig. 1. Wrap the tape on the
7 9
a 900-g weight shall be used for tapes varying in width from 1 ⁄16 to 1 ⁄16
mandrel at a speed of approximately 18 in. (450 mm)/min.
in. (36.5 to 39.7 mm). Tapes with widths outside these ranges shall be
Using the winding procedure and weights just described, half 1
tested in accordance with their width (determined to the nearest ⁄16 in.
lap the marked tape sample on the mandrel over the first piece (1.59 mm). For example, a 1 ⁄8-in. (28.6 mm) wide tape shall be tested
with a 675-g weight. The unwinding weights shall be made to a tolerance
of tape. With the winding weight attached, return the test
of 62%.
fixture to a horizontal position and allow the tape to bond for
1 min. Remove the winding weight from the tape and the
8. Report
handle from the fixture and proceed with the unwinding test.
8.1 Report the following information:
7.2 Unwinding—After the tape has bonded for 1 min, attach
8.1.1 Description of material, type of cross-section, tape
a load of 21 oz (600 g)/in. (25 mm) of the original tape width
width and thickness,
8.1.2 Winding weight, in grams,
8.1.3 Unwinding weight, in grams, and
8.1.4 Length of unwind, to the nearest ⁄4 unit.
9. Precision and Bias
9.1 This test method has been in use for many years, but no
information has been presented to ASTM upon which to base
a statement of precision. No activity has been planned to
develop such information.
9.2 This test method has no bias because the value for
adhesion is determined solely in terms of this test method
itself.
BOND STRENGTH
10. Terminology
10.1 Definitions of Terms Specific to This Standard:
10.1.1 bond strength, of unvulcanized and semivulcanized
supported silicone rubber tapes—the strength of chemical
linkages achieved between successive layers of tape under
FIG. 1 Inclined Mandrel Tack Test Fixture controlled vulcanizing conditions.
´1
D2148 − 02 (2008)
11. Significance and Use 15.3 Superimpose one strip on another, front side to back
side, to form a specimen.
11.1 The bond strength is an indication of the physical
integrity that can be expected under end use conditions in 15.4 Separate the two strips at one end for a distance of
which the insulating tapes are applied with an overlap. about 1 in. (25 mm) and insert a strip of release film.
15.5 Preheat the press to 177 °C (350 °F).
12. Apparatus
15.6 Assemble the test specimens between two sheets of
12.1 Bonding Press—A platen press having the following
release film. Place the assembly on the unheated silicone
characteristics:
rubber pad and insert in the press.
12.1.1 A temperature range to 205 °C (400 °F).
15.7 Close the press and apply 50 psi (345 kPa) pressure to
12.1.2 A thermostat that will allow a set temperature to be
the specimens for 5 min.
maintained 65°C(6 9 °F).
12.1.3 A pressure regulator to allow setting and control of
15.8 Release the pressure, remove the specimens, and allow
the platen pressure.
them to cool for at least 5 min.
12.1.4 A pressure indicator to show the pressure being
15.9 Remove the release film and trim the specimens to a
exerted between the platen faces.
1-in. (25-mm) width.
12.1.5 A timer to allow measurement of bonding time. It is
15.10 Clamp one separated end in the upper jaw of the
preferred that a controller-type timer be used which will both
testing machine; peel the other separated end back 180 deg and
indicate bonding time and also cause the platen pressure to be
clamp it in the lower jaw.
released and the platens separated at the end of the bonding
period.
15.11 Adjustthetestingmachinetoprovideajawseparation
rate of 20 in. (500 mm) per min. If the pendulum-type machine
12.2 Temperature-Measuring Device(s) to indicate face
isused,disengagethepawlsduringthetest.Recordtheaverage
temperature of the platen(s).
observed force for each specimen using the technique de-
12.3 Silicone Rubber Pad, approximately ⁄8 in. (3.20 mm)
scribed for adhesion strength in Test Methods D1000.
thick, 60 to 70 Shore A durometer hardness, larger in dimen-
sion than the specimens to be tested. This is used as a
16. Report
pressure-equalizing device, compensating for irregularities in
16.1 Report the following information:
either the specimen or the platens.
16.1.1 Bond strength of each specimen and the average in
12.4 Polytetrafluoroethylene or suitable release film, three
pounds per inch or newtons per metre of width, and
sheets, approximately 2 to 4 mils (0.05 to 0.10 mm) thick. One
16.1.2 Bonding time, pressure, and temperature used, if
sheet is placed on each side of the specimens as a release sheet,
other than as specified.
the third sheet being used to separate the ends of the two test
specimens.
17. Precision and Bias
12.5 Testing Machine—A power-driven testing machine of
17.1 Thistestmethodhasbeeninuseformanyyears,butno
either the cross head or dead-weight pendulum type. The
information has been presented to ASTM upon which to base
machine shall be equipped with a tension weighing device
a statement of precision. No activity has been planned to
having a maximum capacity of 50 lb (22.7 kg) graduated to
develop such information.
read 0.1 lb (50 g) or less per scale division.
17.2 This test method has no bias because the value for
bond strength is determined solely in terms of this test method
13. Test Specimen
itself.
13.1 The test specimen shall be selected to be representative
DIELECTRIC BREAKDOWN VOLTAGE
of the material to be tested. The size of sample shall be
sufficient to give six strips at least 1.25 to 1.5 in. (32 to 38 mm)
18. Scope
wide and 6 in. (150 mm) long. Care should be taken to prevent
contamination.
18.1 This test method covers determination of the break-
down voltage of unsupported bondable silicone rubber tapes
14. Conditioning
with tapered edges (Note 3) for use as electrical insulation.
14.1 The specimen shall not be exposed to temperatures
18.2 The method to be used for rectangular cross section
above 30 °C (85 °F) before bonding. The tests shall be
tapes is described in Test Methods D1458.
conductedintheStandardLaboratoryAtmosphereasdescribed
NOTE 3—Tapes with tapered edges include such cross sections as
in Practice D6054.
triangular and lens-shaped.
15. Procedure
19. Significance and Use
15.1 Cut the strips of material to 1.25 to 1.5 in. (32 to 38
19.1 The level of dielectric breakdown voltage as deter-
mm) wide and at least 6 in. (150 mm) long, the length being
minedbythistestisonemeasureofthequalityofbothmaterial
measured in the warp or machine direction of the backing.
and fabrication methods used in producing the tape. This
15.2 Remove any interliner material. voltage value should not be compared directly with the results
´1
D2148 − 02 (2008)
of tests made on rectangular cross section tapes. For further Solidly ground all electrically conductive parts which it is
details, refer to Test Method D149. possible for a person to contact during the test. Provide means
for use at the completion of any test to ground any parts which
20. Apparatus
were at high voltage during the test or have the potential for
acquiring an induced charge during the test or retaining a
20.1 Test Fixture, designed to support a removable mandrel
charge even after disconnection of the voltage source. Thor-
⁄8 in. (15.9 mm) in diameter and about (20 in.) (500 mm) in
oughly instruct all operators as to the correct procedures for
length. This fixture may be a modification of the one described
performing tests safely. When making high voltage tests,
in 5.1.
particularly in compressed gas or in oil, it is possible for the
20.2 Voltage Source,capableofapplyingalternatingvoltage
energy released at breakdown to be suffıcient to result in fire,
and increasing it at the rate of 500 V/s. This equipment shall
explosion, or rupture of the test chamber. Design test equip-
conform to the requirements of Test Method D149.
ment, test chambers, and test specimens so as to minimize the
possibility of such occurrences and to eliminate the possibility
21. Test Specimen
of personal injury. If the potential for fire exists, have fire
21.1 The test specimen shall consist of lengths of bond
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
An American National Standard
e1
Designation:D2148–95 Designation: D 2148 – 02 (Reapproved 2008)
Standard Test Methods for
Bondable Silicone Rubber Tapes Used for Electrical
Insulation
This standard is issued under the fixed designation D 2148; 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 (´) indicates an editorial change since the last revision or reapproval.
e NOTE—The units statement in subsection 1.3 was corrected editorially in July 2008.
1. Scope
1.1 These test methods cover tests for bondable silicone rubber tapes which form a sealed structure either with the application
of heat (and pressure if needed) or by the process of auto-adhesion (self-fusing).
1.2 The methods appear in the following sections:
Test Method Section
Adhesion 3-9
Bond Strength 10-17
Dielectric Breakdown Voltage 18-25
Hardness 40
Length 32 and 33
Thickness 26-31
Width 35-39
1.3The values stated in inch-pound units are to be regarded as the standard except for °C.
1.3 The values stated in inch-pound units are to be regarded as standard, except for °C. The values in parentheses are
mathematical conversions to SI units that are provided for information only and are not considered standard.
1.4 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 a specific hazard statement see 22.1.1.
2. Referenced Documents
2.1 ASTM Standards:
D 149 Test MethodsMethod for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials
at Commercial Power Frequencies
D 374 Test Methods for Thickness of Solid Electrical Insulation
2,
D618Practice for Conditioning Plastics and Electrical Insulating Materials for Testing 1000 Test Methods for Pressure-
Sensitive Adhesive-Coated Tapes Used for Electrical and Electronic Applications
D1000Test Methods for Pressure-SensitiveAdhesive Coated Tapes Used for Electrical and ElectronicApplications 1458 Test
Methods for Fully Cured Silicone Rubber-Coated Glass Fabric and Tapes for Electrical Insulation
D1458Test Methods for Fully Cured Silicone Rubber-Coated Glass Fabric and Tapes for Electrical Insulation 2240 Test
Method for Rubber PropertyDurometer Hardness
D2240Test Method for Rubber Property—Durometer Hardness 6054 Practice for Conditioning Electrical Insulating Materials
for Testing
2.2 ASTM Adjuncts:
Tack tester (one drawing)
These methods are under the jurisdiction ofASTM Committee D-9 on Electrical and Electronic Insulating Materials and are the responsibility of Subcommittee D09.07
on Flexible and Rigid Insulating Materials.
Current edition approved Jan. 15, 1995. Published March 1995. Originally published as D2148–63T. Last previous edition D2148–90.
These methods are under the jurisdiction of ASTM Committee D09 on Electrical and Electronic Insulating Materials and are the direct responsibility of Subcommittee
D09.07 on Flexible and Rigid Insulating Materials.
´1
Current edition approved May 1, 2008. Published July 2008. Originally approved in 1963. Last previous edition approved in 2002 as D 2148 – 02 .
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
, Vol 10.01.volume information, refer to the standard’s Document Summary page on the ASTM website.
Annual Book of ASTM Standards, Vol 08.01.
Available from ASTM International Headquarters. Order Adjunct No. ADJD2148. Original adjunct produced in 1965.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
e1
D 2148 – 02 (2008)
ADHESION
3. Scope
3.1 This test method covers the determination of the self-adhesion of unsupported, self-fusing silicone rubber rectangular and
taper-edge (Note 1) tape designed for use as electrical insulation.
NOTE 1—Taper-edge tape includes such cross sections as triangular, lens, etc.
4. Significance and Use
4.1 Self-adhesion is a primary initial property since it affects layer-to-layer bonding. The integrity of the bond can significantly
affect the electrical and physical performance of the insulation system. Therefore, the degree of self-adhesion is directly related
to apparatus performance.
4.2 A high degree of self-adhesion is desirable for most electrical applications. In this test, a short unwinding length indicates
a high degree of self-adhesion.
4.3 This test method has been found useful as a quality control test for lot acceptance.
5. Apparatus
5.1 Inclined Mandrel Tack Test Fixture—AsuggestedfixtureisshowninFig.1. Themandrelshallconsistofa ⁄8-in.(15.9-mm)
diameter aluminum rod mounted in low-friction bearings. Good alignment of bearings is necessary for accurate results. When
properly assembled, the mandrel shall turn freely when loaded with a 1-oz (30-g) weight suspended from a cotton thread wound
in a single layer at the center of the mandrel.
5.2 Weights, as specified in Section 7 and means for attachment.
6. Test Specimen
6.1 Atest specimen shall consist of two pieces of tape 12 to 15 in. (25(300 to 380 mm) long. Divisions spaced 1 in. (25.4 mm)
apart shall be marked off on one piece of tape. If tapes contain an interliner, the interliner shall be removed just prior to wrapping
the mandrel. Dirt and other forms of contamination shall be avoided.
7. Procedure
7.1 Winding—Half lap the unmarked specimen perfectly on the mandrel of the test fixture, using the suggested weight as shown
in Table 1. These weights are not critical. However, they are necessary to get intimate contact and conformability of the tape. To
obtain perfect half lapping, tilt the tack tester at an appropriate angle as shown in Fig. 1. Wrap the tape on the mandrel at a speed
of approximately 18 in. (450 mm)/min. Using the winding procedure and weights just described, half lap the marked tape sample
on the mandrel over the first piece of tape. With the winding weight attached, return the test fixture to a horizontal position and
allow the tape to bond for 1 min. Remove the winding weight from the tape and the handle from the fixture and proceed with the
unwinding test.
7.2 Unwinding—Afterthetapehasbondedfor1min,attachaloadof21oz(600g)/in.(25mm)oftheoriginaltapewidth(Note
2). Attach the weight to the free end of the tape by means of a bulldog paper clamp or other suitable device. Release the weight
FIG. 1 Inclined Mandrel Tack Test Fixture
e1
D 2148 – 02 (2008)
TABLE 1 Suggested Winding Weights For 1-in. Wide Tapes
NOTE 1—Winding weights are based on cross-sectional area and have
been selected to produce approximately the same unit stress on all
cross-sections. For tapes of dimensions not listed, use a winding weight of
2 2
approximately 300 g/0.01 in. (6.3 mm )
Tape Thickness, in. (mm)
Weight, oz (g)
Triangular Rectangular
0.020 (0.51) 0.010 (0.25) 300
0.030 (0.76) 0.015 (0.38) 450
0.040 (1.02) 0.020 (0.51) 600
0.050 (1.27) 0.025 (0.64) 750
0.060 (1.52) 0.030 (0.76) 900
0.070 (1.78) . 1050
0.070 (1.78) . 37.0 (1050)
0.080 (2.03) . 1200
0.080 (2.03) . 42.3 (1200)
and record the length of tape unwound in 3 min. Although the original 1-in. dimensions will elongate due to the unwind weight,
consider each division as one unit. While the winding weights are not critical, the use of proper unwinding weights is mandatory.
Consistent and comparable results depend upon accurate width measurements and the use of the proper unwinding weight.
NOTE 2—Commercial tapes are usually made to a 6 ⁄16-in. (61.59- mm) tolerance. Therefore a 600-g weight shall be used for tapes varying in width
15 1 3 5
from ⁄16 to 1 ⁄16 in. (23.8 to 27 mm); a 750-g weight shall be used for tapes varying in width from 1 ⁄16 to 1 ⁄16 in. (30.2 to 33.3 mm) and a 900-g weight
7 9
shall be used for tapes varying in width from 1 ⁄16 to 1 ⁄16 in. (36.5 to 39.7 mm). Tapes with widths outside these ranges shall be tested in accordance
1 1
with their width (determined to the nearest ⁄16 in. (1.59 mm). For example, a 1 ⁄8-in. (28.6 mm) wide tape shall be tested with a 675-g weight. The
unwinding weights shall be made to a tolerance of 62%.
8. Report
8.1 Report the following information:
8.1.1 Description of material, type of cross-section, tape width and thickness,
8.1.2 Winding weight, in grams,
8.1.3 Unwinding weight, in grams, and
8.1.4 Length of unwind, to the nearest ⁄4 unit.
9. Precision and Bias
9.1The precision of this test method has not been determined. Since there is no accepted reference material, no statement on bias
is being made.
9.1 This test method has been in use for many years, but no information has been presented to ASTM upon which to base a
statement of precision. No activity has been planned to develop such information.
9.2 This test method has no bias because the value for adhesion is determined solely in terms of this test method itself.
BOND STRENGTH
10. Terminology
10.1 Definitions of Terms Specific to This Standard:
10.1.1 bond strength, of unvulcanized and semivulcanized supported silicone rubber tapes—the strength of chemical linkages
achieved between successive layers of tape under controlled vulcanizing conditions.
11. Significance and Use
11.1 The bond strength is an indication of the physical integrity that can be expected under end use conditions in which the
insulating tapes are applied with an overlap.
12. Apparatus
12.1 Bonding Press—A platen press having the following characteristics:
12.1.1 A temperature range to 205 °C (400 °F).
12.1.2 A thermostat that will allow a set temperature to be maintained 69°F (65°C). 65°C(6 9 °F).
12.1.3 A pressure regulator to allow setting and control of the platen pressure.
12.1.4 A pressure indicator to show the pressure being exerted between the platen faces.
12.1.5 A timer to allow measurement of bonding time. It is preferred that a controller-type timer be used which will both
indicate bonding time and also cause the platen pressure to be released and the platens separated at the end of the bonding period.
12.2 Temperature-Measuring Device(s) to indicate face temperature of the platen(s).
e1
D 2148 – 02 (2008)
12.3 Silicone Rubber Pad, approximately ⁄8 in. (3.20 mm) thick, 60 to 70 ShoreAdurometer hardness, larger in dimension than
the specimens to be tested. This is used as a pressure-equalizing device, compensating for irregularities in either the specimen or
the platens.
12.4 Polytetrafluoroethylene or suitable release film, three sheets, approximately 2 to 4 mils (0.05 to 0.10 mm) thick. One sheet
is placed on each side of the specimens as a release sheet, the third sheet being used to separate the ends of the two test specimens.
12.5 Testing Machine—A power-driven testing machine of either the cross head or dead-weight pendulum type. The machine
shall be equipped with a tension weighing device having a maximum capacity of 50 lb (22.7 kg) graduated to read 0.1 lb (50 g)
or less per scale division.
13. Test Specimen
13.1 The test specimen shall be selected to be representative of the material to be tested. The size of sample shall be sufficient
togivesixstripsatleast1.25to1.5in.(32to38mm)wideand6in.(150mm)long.Careshouldbetakentopreventcontamination.
14. Conditioning
14.1 The specimen shall not be exposed to temperatures above 85°F (30°C) 30 °C (85 °F) before bonding. The tests shall be
conducted in the Standard Laboratory Atmosphere as described in Practice D618D 6054.
15. Procedure
15.1 Cut the strips of material to 1.25 to 1.5 in. (32 to 38 mm) wide and at least 6 in. (150 mm) long, the length being measured
in the warp or machine direction of the backing.
15.2 Remove any interliner material.
15.3 Superimpose one strip on another, front side to back side, to form a specimen.
15.4 Separate the two strips at one end for a distance of about 1 in. (25 mm) and insert a strip of release film.
15.5 Preheat the press to 177 °C (350 °F).
15.6 Assemble the test specimens between two sheets of release film. Place the assembly on the unheated silicone rubber pad
and insert in the press.
15.7 Close the press and apply 50 psi (345 kPa) pressure to the specimens for 5 min.
15.8 Release the pressure, remove the specimens, and allow them to cool for at least 5 min.
15.9 Remove the release film and trim the specimens to a 1-in. (25-mm) width.
15.10 Clamp one separated end in the upper jaw of the testing machine; peel the other separated end back 180 deg and clamp
it in the lower jaw.
15.11 Adjust the testing machine to provide a jaw separation rate of 20 in. (500 mm) per min. If the pendulum-type machine
is used, disengage the pawls during the test. Record the average observed force for each specimen using the technique described
for adhesion strength in Test Methods D 1000.
16. Report
16.1 Report the following information:
16.1.1 Bond strength of each specimen and the average in pounds per inch or newtons per metre of width, and
16.1.2 Bonding time, pressure, and temperature used, if other than as specified.
17. Precision and Bias
17.1The precision of this test method has not been determined. Since there is no accepted reference material, no statement on
bias is being made.
17.1 This test method has been in use for many years, but no information has been presented to ASTM upon which to base a
statement of precision. No activity has been planned to develop such information.
17.2 This test method has no bias because the value for bond strength is determined solely in terms of this test method itself.
DIELECTRIC BREAKDOWN VOLTAGE
18. Scope
18.1 This test method covers determination of the breakdown voltage of unsupported bondable silicone rubber tapes with
tapered edges (Note 3) for use as electrical insulation.
18.2 The method to be used for rectangular cross section tapes is described in Test Methods D 1458.
NOTE 3—Tapes with tapered edges include such cross sections as triangular and lens-shaped.
19. Significance and Use
19.1 The level of dielectric breakdown voltage as determined by this test is one measure of the quality of both material and
fabrication methods used in producing the tape. This voltage va
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