1、Designation: D2305 10An American National StandardStandard 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, th
2、e year of last revision. A number 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 tha
3、t areto be used for electrical 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 pr
4、ovided for information only.1.4 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 env
5、ironment, note these conditionsand the time of exposure to this new environment.6. Procedure6.1 Unless otherwise specified in the individual test meth-ods, test the specimens in the Standard LaboratoryAtmosphere23 6 2C, 50 6 5 % R.H. prescribed in Practice D6054.THICKNESS7. Significance and Use7.1 T
6、he determination of film thickness 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 t
7、hickness of the material; other properties, such as permit-tivity, cannot be calculated without a proper determination ofthickness unless special techniques are used.8. Procedure8.1 Use Method C of Test Methods D374 for this measure-ment, with the apparatus modified as follows: Use a presserfoot of
8、6.25 6 0.05 mm (250 6 1 mil) diameter, and an anvilsurface, 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 t
9、hick-nesses to the nearest 0.5 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 familiar
10、with this method have determined 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.1
11、0.2 BiasThis test method has no 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
12、 principaldirections, each 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
13、widthprior to the application 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 potenti
14、al to occur when a film isexposed 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 a
15、t least 300 mm (12 in.).14. Test 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
16、the initial and final measurements are made.16. 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 specimenD2305 102f
17、reely in the oven at the time 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 n
18、ot whip.17. Calculation17.1 Calculate the liner dimensional change as follows:Linear change, % 5 Dt2 Dv!/Dv# 3 100 (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
19、 for each direction.18. Report18.1 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 transvers
20、e directions of thefilm, and18.1.4 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 i
21、nformation.19.2 BiasThis test method 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 indicati
22、on of its ability to withstandelectric 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 exposure
23、s, providing that sufficientexperience 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
24、 is especially truewith thinner 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
25、(14-in.) diam-eter electrodes are 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 c
26、hange in electrode size can make 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 fiel
27、d pattern, or both, to give erroneousresults.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 anddielec
28、tric strength in accordance with Test Method D149, andin accordance with the applicable sections of this test method.Unless otherwise specified, make ten breakdown measure-ments, equally spaced throughout the specimen.NOTE 4When testing films in a medium other than air, it is possiblethat different
29、results will be obtained.(WarningLethal 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 conducti
30、ve parts which it ispossible for 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
31、 the voltage source. Thor-oughly 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
32、test chamber. Design test equip-ment, test chambers, and test specimens so as to minimize thepossibility of such occurrences and to eliminate the possibilityof personal injury. If the potential for fire exists, have firesuppression equipment available.)24. Application of Voltage24.1 Unless otherwise
33、 specified, use the short-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,D2305 10325.1.2 Average thickness of breakdown specimens,25.1.3 Average, maximum, and minimum dielectric strength(opt
34、ional),25.1.4 Ambient medium and ambient 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 sever
35、e service conditions such ashigh temperature 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 eac
36、h other by at least one power of ten.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 Tes
37、t Methods D257, using stripelectrodes 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 cleangl
38、oves.28.4 Before testing any film of 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.
39、28.7 Use an electrification time of 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 uponwhic
40、h to base a statement of precision. 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
41、.32. Test Specimen32.1 Prepare five 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 or
42、otherwise affect the test specimen.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
43、the volume resistivity in accordance 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 many
44、years, but no information has been 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 ME
45、THOD FOR MEASURING THETENDENCY TO CORRODE 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
46、a film on metalsunder conditions of high humidity when, and if, subjected to anelectrical potential. While other factors also are of importancein controlling metal corrosion, the total amount of electrolyticcorrosion of the metal is proportional to the currents carried bythe film.38. Procedure38.1 D
47、etermine the surface resistivity 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 lea
48、st five determinations for 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 is de-scribed in Test Methods D1000.D2305 10439. Report39.1 Report the following information
49、:39.1.1 Identification of the film,39.1.2 Width of the film,39.1.3 Number of measurements, and39.1.4 Median, minimum, and maximum resistance in me-gohms.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. Sign
