1、Designation: D 2305 02An American National StandardStandard Test Methods forPolymeric Films Used for Electrical Insulation1This standard is issued under the fixed designation D 2305; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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
3、that 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
4、 provided for information only.1.4 The procedures appear in the following sections:Procedure SectionsConditioning 5 and 6Dielectric Breakdown Voltage therefore,the specimen should be in the stated conditioning environmentwhen the test is being performed. When the test is performedin a different envi
5、ronment, note these conditions and the timeof exposure to this new environment.6. Procedure6.1 Unless otherwise specified in the individual test meth-ods, test the specimens in the Standard Laboratory Atmosphere23 6 2C, 50 6 5 % R.H. prescribed in Practice D 6054.THICKNESS7. Significance and Use7.1
6、The 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
7、thickness 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 D 374 for this measure-ment, with the apparatus modified as follows: Use a presserfoot o
8、f 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
9、 thick-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 E 691 has not been conducted. Persons famil
10、iarwith 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 apparatu
11、s.10.2 BiasThis test method has no bias because the valuefor thickness is determined solely in terms of this test method.TENSILE PROPERTIES11. Procedure11.1 Use Method A of Test Methods D 882. Report dataonly for the specific tests required by a specification.11.2 Prepare five specimens in each of t
12、he two 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 thicknes
13、s and 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 may occur
14、when a film is exposed toelevated temperatures during a manufacturing process or whilein 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
15、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 the initial
16、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 specimenD 23052freely in the o
17、ven 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 not whip.17. Ca
18、lculation17.1 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 for each dire
19、ction.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 transverse directions o
20、f 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 information.19.
21、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 indication of its abil
22、ity to withstandelectric stress. This value should be used primarily as anindication of quality and for comparison of different lots ortypes of the same material. Secondarily, this value may beuseful as a design criterion, particularly when considering shortterm exposures, providing that sufficient
23、experience has beengained to give an adequate correlation between this test and theproposed end uses.20.2 Unless special precautions are taken, these test resultsmay be just a measure of the quality of the electrode surfacesand the electrical apparatus. This is especially true with thinnerfilms.20.3
24、 For further details on the significance of this test, referto Test Method D 149.21. Apparatus21.1 Use apparatus that conforms to that specified in TestMethod D 149, including the 25-mm (1-in.) diameter elec-trodes described therein. As an exception, the 6.4-mm (14-in.)diameter electrodes are permit
25、ted where only narrow tape isavailable; and note such exceptions in the report. For furtherdetails on electrodes refer to the electrode section of TestMethod D 149.NOTE 2Tests made with different size electrodes are not necessarilycomparable. In many cases, a change in electrode size can make asigni
26、ficant 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 erroneousre
27、sults.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 with Test M
28、ethod D 149, 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, differentresults may be obtained.(WarningLethal voltages are a pote
29、ntial 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 a person to contact during
30、 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 instruct all operators as
31、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 test equip-ment, test chambers, and te
32、st 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 specified, use the short-time testmethod with a rate of ri
33、se of 500 V/s.25. Report25.1 Unless otherwise specified, report the following infor-mation:25.1.1 Average breakdown voltage,D 2305325.1.2 Average thickness of breakdown specimens,25.1.3 Average, maximum, and minimum dielectric strength(optional),25.1.4 Ambient medium and ambient condition,25.1.5 Con
34、ditioning 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 temperature and high humidit
35、y. Its primary use should beas an indication of quality and for comparison of different lotsor types of the same material. Secondarily, this test may beused to classify materials into broad groups that differ fromeach other by at least one power of ten.27. Conditioning27.1 Use one or more of the fol
36、lowing conditions (seePractice D 6054):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 D 257, usingstrip electrodes as shown in Fig. number 3 of that test metho
37、d.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 of questionable cleanliness,clean it in accordan
38、ce 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 1 min 6 5sat100Vdc6 5 V unless otherwise speci
39、fied (see 23.1).29. Report29.1 Report all the items listed in Test Methods D 257.30. 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. No activity has beenplanned to develop such i
40、nformation.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 D 257.32. Test Specimen32.1 Prepare five specimens by depositing a 25-mm (1-in.)diame
41、ter 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.NOTE 6For films greater than 0.12 mm (5 mils)
42、 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 D 257.34. Calculation34.1 Calculate the volume resistivity in accordance withTest Methods D 257 except that, where
43、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 D 257.36. Precision and Bias36.1 PrecisionThis test method has been in use for manyyears, but no information has been presented to ASTM uponwhich to base a stat
44、ement 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 CORRODE METALS37. Significance and Use37.1
45、Severe electrolytic corrosion may cause open circuitfailures, leakage current paths, or weak pitted wires. Theresistance test method is of value as an indirect indication ofthe possible corrosive effect of a film on metals under condi-tions of high humidity when, and if, subjected to an electricalpo
46、tential. While other factors also are of importance incontrolling metal corrosion, the total amount of electrolyticcorrosion of the metal is proportional to the currents carried bythe film.38. Procedure38.1 Determine the surface resistivity of the film in accor-dance with Section 28, with the follow
47、ing 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 D 5032. Make at least five determinations for surfaceresistivity at this environmental condition using an elec
48、trifica-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 D 1000.D 2305439. Report39.1 Report the following information:39.1.1 Identification of the film,39.1.2 Width of the film,39.1.3 Number of measurements, a
49、nd39.1.4 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. Significance and Use41.1 See Test Methods D 150.42. Electrodes42.1 See Test Methods D 150.42.2 If tests
