1、Designation: D2305 10Standard Test Methods forPolymeric Films Used for Electrical Insulation1This standard is issued under the fixed designation D2305; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A nu
2、mber in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods cover the testing of homogeneousorganic polymer films not over 2.4 mm (95 mils) thick that areto be used for electrica
3、l insulation.1.2 These test methods are not necessarily applicable totesting films in combinations with a coating, another film, orwith other types of substrate, such as fabrics or papers.1.3 The values stated in SI units are the standard. The valuesin parentheses are provided for information only.1
4、.4 The procedures appear in the following sections:Procedure SectionsConditioning 5 and 6Dielectric Breakdown Voltage therefore,the specimen needs to be in the stated conditioning environ-ment when the test is being performed. When the test isperformed in a different environment, note these conditio
5、nsand the time of exposure to this new environment.6. Procedure6.1 Unless otherwise specified in the individual testmethods, test the specimens in the Standard Laboratory Atmo-sphere 23 6 2C, 50 6 5 % R.H. prescribed in Practice D6054.THICKNESS7. Significance and Use7.1 The determination of film thi
6、ckness is frequently nec-essary to ensure (1) the satisfactory production of electricalequipment, and (2) the maintenance of desired electricalproperties of the film during the use of the electrical equip-ment. Some properties, such as dielectric strengths, vary withthe thickness of the material; ot
7、her properties, such aspermittivity, cannot be calculated without a proper determina-tion of thickness unless special techniques are used.8. Procedure8.1 Use Method C of Test Methods D374 for thismeasurement, with the apparatus modified as follows: Use apresser foot of 6.25 6 0.05 mm (250 6 1 mil) d
8、iameter, and ananvil surface, upon which the specimen rests, of at least 50-mm(2-in.) diameter. Apply a force of 0.84 6 0.2N(36 0.75) ozfto the specimen. Take ten measurements, equally spacedthroughout the specimen.9. Report9.1 Report the average, maximum, and minimum thick-nesses to the nearest 0.5
9、 m (0.02 mil) for specimens thinnerthan 50 m (2 mils) and to the nearest 1 m (0.04 mil) forspecimens 50 m (2 mils) or more in thickness.10. Precision and Bias10.1 PrecisionA formal round robin test in accordancewith Practice E691 has not been conducted. Persons familiarwith this method have determin
10、ed that two test results can beexpected (with a probability of 95 %) to agree within 3 %.Each test result is the average of 10 thickness readings taken ona single sample of polyimide film in one laboratory in which amultiple number of operators used the same apparatus.10.2 BiasThis test method has n
11、o bias because the valuefor thickness is determined solely in terms of this test method.TENSILE PROPERTIES11. Procedure11.1 Use MethodAof Test Methods D882. Report data onlyfor the specific tests required by a specification.11.2 Prepare five specimens in each of the two principaldirections, each 12
12、by 200 mm (0.5 by 8 in.).11.3 Unless otherwise stated, measure the tensile strengthand tensile elongation, with initial jaw separation of 100 6 2mm (4.06 0.08 in.) and rate of jaw separation of 50 6 2mm(2 6 0.08 in.)/min.11.4 For each specimen, record the thickness and widthprior to the application
13、of the tensile force. Use these values tocalculate the tensile strength for each specimen. Report thetensile strength in MPa (lbf/in.2).STRAIN RELIEF12. Significance and Use12.1 The strain relief test gives an indication of the dimen-sional changes that have the potential to occur when a film isexpo
14、sed to elevated temperatures during a manufacturingprocess or while in service.13. Apparatus13.1 Ovens, shall be of a forced-convection type capable ofmaintaining the specified temperature6 5C.13.2 Scale, graduated in 0.25-mm (0.01-in.) divisions with atotal length of at least 300 mm (12 in.).14. Te
15、st Specimen14.1 Prepare test specimens 25 mm (1 in.) wide and at least300 mm (12 in.) long. When sheets or rolls are greater than 300mm wide, also cut specimens in the transverse direction.15. Conditioning15.1 Condition test specimens in accordance with Section 6before the initial and final measurem
16、ents are made.D2305 10216. Procedure16.1 Mark gage lines on five specimens approximately 25mm (1 in.) in from the ends of the specimen at a gage distanceof 250 mm (10.0 in.). Determine the initial gage distance bymeasuring both edges of each specimen. Hang the specimenfreely in the oven at the time
17、and temperature specified for thematerial. Determine the final gage distance by measurementafter conditioning.16.1.1 Use a marking technique that does not affect theproperties or dimensions of the material.16.1.2 Adjust the air flow in the oven so that the specimensdo not whip.17. Calculation17.1 Ca
18、lculate the liner dimensional change as follows:Linear change, % 5 Dt2 Dv!/Dv# 3100 (1)where:Dt= final dimensions, in. (mm), andDv= original dimension, in. (mm).A negative value denotes shrinkage, and a positive valueindicates expansion.17.2 Average the values obtained for each direction.18. Report1
19、8.1 Report the following information:18.1.1 Identification of the material tested,18.1.2 Test conditions (time and temperature), including theconditioning of the test specimens,18.1.3 Average percentage linear change and maximumdeviations, in both machine and transverse directions of thefilm, and18.
20、1.4 Any curl at the edges or other visual defects.19. Precision and Bias19.1 PrecisionThis test method has been in use for manyyears, but no information has been presented to ASTM uponwhich to base a statement of precision. No activity has beenplanned to develop such information.19.2 BiasThis test m
21、ethod has no bias because the valuefor strain relief is determined solely in terms of this test methoditself.DIELECTRIC BREAKDOWN VOLTAGE ANDDIELECTRIC STRENGTH20. Significance and Use20.1 The dielectric breakdown voltage and dielectricstrength of a film is an indication of its ability to withstande
22、lectric stress. This value needs to be used primarily as anindication of quality and for comparison of different lots ortypes of the same material. Secondarily, this value willpotentially be useful as a design criterion, particularly whenconsidering short term exposures, providing that sufficientexp
23、erience has been gained to give an adequate correlationbetween this test and the proposed end uses.20.2 Unless special precautions are taken, these test resultswill potentially be just a measure of the quality of the electrodesurfaces and the electrical apparatus. This is especially truewith thinner
24、 films.20.3 For further details on the significance of this test, referto Test Method D149.21. Apparatus21.1 Use apparatus that conforms to that specified in TestMethod D149, including the 25-mm (1-in.) diameter electrodesdescribed therein. As an exception, the 6.4-mm (14-in.) diam-eter electrodes a
25、re permitted where only narrow tape isavailable; and note such exceptions in the report. For furtherdetails on electrodes refer to the electrode section of TestMethod D149.NOTE 2Tests made with different size electrodes are not necessarilycomparable. In many cases, a change in electrode size can mak
26、e asignificant difference in test results. Take care to keep electrodes parallel,clean, and free of pits.22. Test Specimen22.1 Test clean specimens only. Surface contamination canform dents when the electrodes are applied to the specimen orcan alter the electrical field pattern, or both, to give err
27、oneousresults.NOTE 3To help prevent the specimen from becoming contaminatedduring the test, it is recommended that the tests be made in a clean,air-conditioned room supplied with filtered air.23. Procedure23.1 Determine the dielectric breakdown voltage in air anddielectric strength in accordance wit
28、h Test Method D149, andin accordance with the applicable sections of this test method.Unless otherwise specified, make ten breakdownmeasurements, equally spaced throughout the specimen.NOTE 4When testing films in a medium other than air, it is possiblethat different results will be obtained.(Warning
29、Lethal voltages are a potential hazard duringthe performance of this test. It is essential that the testapparatus, and all associated equipment electrically connectedto it, be properly designed and installed for safe operation.Solidly ground all electrically conductive parts which it ispossible for
30、a person to contact during the test. Provide meansfor use at the completion of any test to ground any parts whichwere at high voltage during the test or have the potential foracquiring an induced charge during the test or retaining acharge even after disconnection of the voltage source. Thor-oughly
31、instruct all operators as to the correct procedures forperforming tests safely. When making high voltage tests,particularly in compressed gas or in oil, it is possible for theenergy released at breakdown to be suffcient to result in fire,explosion, or rupture of the test chamber. Design testequipmen
32、t, test chambers, and test specimens so as to minimizethe possibility of such occurrences and to eliminate thepossibility of personal injury. If the potential for fire exists,have fire suppression equipment available.)D2305 10324. Application of Voltage24.1 Unless otherwise specified, use the short-
33、time testmethod with a rate of rise of 500 V/s.25. Report25.1 Unless otherwise specified, report the following infor-mation:25.1.1 Average breakdown voltage,25.1.2 Average thickness of breakdown specimens,25.1.3 Average, maximum, and minimum dielectric strength(optional),25.1.4 Ambient medium and am
34、bient condition,25.1.5 Conditioning of specimens,25.1.6 Rate of voltage increase, and25.1.7 Size and material of electrodes used.SURFACE RESISTIVITY26. Significance and Use26.1 Surface resistivity is of value for determining thesuitability of a material under severe service conditions such ashigh te
35、mperature and high humidity. Its primary use needs tobe as an indication of quality and for comparison of differentlots or types of the same material. Secondarily, it is possiblethat this test will be used to classify materials into broad groupsthat differ from each other by at least one power of te
36、n.27. Conditioning27.1 Use one or more of the following conditions (seePractice D6054):27.1.1 Condition 18/35/90,27.1.2 Condition 2/90, or27.1.3 Condition 2/130.28. Procedure28.1 Determine the surface resistivity in the conditioningatmosphere in accordance with Test Methods D257, using stripelectrod
37、es as shown in Fig. number 3 of that test method.28.2 It is important that the specimens not be contaminatedduring the placement of the electrodes.28.3 Do not allow the specimens used for test to contactunclean surfaces and do not touch them without wearing cleangloves.28.4 Before testing any film o
38、f questionable cleanliness,clean it in accordance with the manufacturers suggestions.28.5 Cut test specimens to a width of 25 mm (1 in.).28.6 Calculate resistivity by multiplying resistance valuesby the ratio of the specimen width to the distance betweenelectrodes.28.7 Use an electrification time of
39、 1 min 6 5sat100Vdc6 5 V unless otherwise specified (see 23.1).29. Report29.1 Report all the items listed in Test Methods D257.30. Precision and Bias30.1 PrecisionThis test method has been in use for manyyears, but no information has been presented to ASTM uponwhich to base a statement of precision.
40、 No activity has beenplanned to develop such information.30.2 BiasThis test method has no bias because the valuefor surface resistivity is determined solely in terms of this testmethod itself.VOLUME RESISTIVITY31. Significance and Use31.1 Refer to Test Methods D257.32. Test Specimen32.1 Prepare five
41、 specimens by depositing a 25-mm (1-in.)diameter electrode of silver conductive paint or evaporatedmetal on each side of the film. Take special care so that thecircles on the two sides are in register.NOTE 5Use a silver paint whose solvent will not cause crazing orotherwise affect the test specimen.
42、NOTE 6For films greater than 0.12 mm (5 mils) in thickness, a guardelectrode is usually required.33. Procedure33.1 Apply 100 V dc for 1 min unless otherwise specified.Measure the volume resistance in accordance with Test Meth-ods D257.34. Calculation34.1 Calculate the volume resistivity in accordanc
43、e withTest Methods D257 except that, where no guard electrode isused, the area is based on the 25-mm (1-in.) diameter electrode.35. Report35.1 Report all items listed in Test Methods D257.36. Precision and Bias36.1 PrecisionThis test method has been in use for manyyears, but no information has been
44、presented to ASTM uponwhich to base a statement of precision. No activity has beenplanned to develop such information.36.2 BiasThis test method has no bias because the valuefor volume resistivity is determined solely in terms of this testmethod itself.RESISTANCE METHOD FOR MEASURING THETENDENCY TO C
45、ORRODE METALS37. Significance and Use37.1 Severe electrolytic corrosion has the potential to causeopen circuit failures, leakage current paths, or weak pittedwires. The resistance test method is of value as an indirectindication of the possible corrosive effect of a film on metalsunder conditions of
46、 high humidity when, and if, subjected to anelectrical potential. While other factors also are of importanceD2305 104in controlling metal corrosion, the total amount of electrolyticcorrosion of the metal is proportional to the currents carried bythe film.38. Procedure38.1 Determine the surface resis
47、tivity of the film in accor-dance with Section 28, with the following exceptions:38.1.1 Condition the specimens for 18 h at a relativehumidity of 966 2 % and 23 6 1C (73 6 2F). Satisfactorymeans of obtaining this relative humidity are described inPractice D5032. Make at least five determinations for
48、 surfaceresistivity at this environmental condition using an electrifica-tion time of 15 s and a voltage of 100 to 130 V dc.NOTE 7Apparatus found satisfactory for these measurements isdescribed in Test Methods D1000.39. Report39.1 Report the following information:39.1.1 Identification of the film,39
49、.1.2 Width of the film,39.1.3 Number of measurements, and39.1.4 Median, minimum, and maximum resistance inmegohms.40. Precision and Bias40.1 PrecisionThis test method has been in use for manyyears, but no information has been presented to ASTM uponwhich to base a statement of precision. No activity has beenplanned to develop such information.40.2 BiasThis test method has no bias because the valuefor surface resistivity is determined solely in terms of this testmethod itself.PERMITTIVITY AND DISSIPATION FACTOR41. Significance and Use41.1 See Test Methods D
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