1、Designation: D2305 18Standard 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. Scope*1.1 These test methods cover the testing of homogeneousorganic polymer films not over 2.4 mm (95 mils) thick that areto be used for electric
3、al 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.
4、1.4 The procedures appear in the following sections:Procedure SectionsConditioning 6 and 7Dielectric 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 conditi
5、onsand the time of exposure to this new environment.7. Procedure7.1 Unless otherwise specified in the individual testmethods, test the specimens in the Standard Laboratory Atmo-sphere 23 6 2C, 50 6 10 % R.H.THICKNESS8. Significance and Use8.1 The determination of film thickness is frequently nec-ess
6、ary 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; other properties, such aspermi
7、ttivity, cannot be calculated without a proper determina-tion of thickness unless special techniques are used.9. Procedure9.1 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) diameter, and ananvil surface
8、, 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.10. Report10.1 Report the average, maximum, and minimum thick-nesses to the nearest 0.5 m (0.02 mil) for specimen
9、s thinnerthan 50 m (2 mils) and to the nearest 1 m (0.04 mil) forspecimens 50 m (2 mils) or more in thickness.11. Precision and Bias11.1 PrecisionA formal round robin test in accordancewith Practice E691 has not been conducted. Persons familiarwith this method have determined that two test results c
10、an 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.11.2 BiasThis test method has no bias because the valuefo
11、r thickness is determined solely in terms of this test method.TENSILE PROPERTIES12. Procedure12.1 Use MethodAof Test Methods D882. Report data onlyfor the specific tests required by a specification.12.2 Prepare five specimens in each of the two principaldirections, each 12 by 200 mm (0.5 by 8 in.).D
12、2305 18212.3 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.12.4 For each specimen, record the thickness and widthprior to the application of the tensile fo
13、rce. Use these values tocalculate the tensile strength for each specimen. Report thetensile strength in MPa (lbf/in.2).STRAIN RELIEF13. Significance and Use13.1 The strain relief test gives an indication of the dimen-sional changes that have the potential to occur when a film isexposed to elevated t
14、emperatures during a manufacturingprocess or while in service.14. Apparatus14.1 Ovens, shall be of a forced-convection type capable ofmaintaining the specified temperature 65C.14.2 Scale, graduated in 0.25-mm (0.01-in.) divisions with atotal length of at least 300 mm (12 in.).15. Test Specimen15.1 P
15、repare 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.16. Conditioning16.1 Condition test specimens in accordance with Section 7before the initial and final measurements are made.17.
16、 Procedure17.1 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 and temperature specified
17、for thematerial. Determine the final gage distance by measurementafter conditioning.17.1.1 Use a marking technique that does not affect theproperties or dimensions of the material.17.1.2 Adjust the air flow in the oven so that the specimensdo not whip.18. Calculation18.1 Calculate the liner dimensio
18、nal 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.18.2 Average the values obtained for each direction.19. Report19.1 Report the following i
19、nformation:19.1.1 Identification of the material tested,19.1.2 Test conditions (time and temperature), including theconditioning of the test specimens,19.1.3 Average percentage linear change and maximumdeviations, in both machine and transverse directions of thefilm, and19.1.4 Any curl at the edges
20、or other visual defects.20. Precision and Bias20.1 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.20.2 BiasThis test method has no bias because
21、the valuefor strain relief is determined solely in terms of this test methoditself.DIELECTRIC BREAKDOWN VOLTAGE ANDDIELECTRIC STRENGTH21. Significance and Use21.1 The dielectric breakdown voltage and dielectricstrength of a film is an indication of its ability to withstandelectric stress. This value
22、 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 sufficientexperience has been gained to
23、 give an adequate correlationbetween this test and the proposed end uses.21.2 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 films.21.3 For further de
24、tails on the significance of this test, referto Test Method D149.22. Apparatus22.1 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 are permitted where only na
25、rrow 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 make asignificant difference
26、in test results. Take care to keep electrodes parallel,clean, and free of pits.23. Test Specimen23.1 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 erroneousresults.D2305 183NOT
27、E 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.24. Procedure24.1 Determine the dielectric breakdown voltage in air anddielectric strength in accordance with Test Method D14
28、9, 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.25. Application of Voltag
29、e25.1 Unless otherwise specified, use the short-time testmethod with a rate of rise of 500 V/s.26. Report26.1 Unless otherwise specified, report the following infor-mation:26.1.1 Average breakdown voltage,26.1.2 Average thickness of breakdown specimens,26.1.3 Average, maximum, and minimum dielectric
30、 strength(optional),26.1.4 Ambient medium and ambient condition,26.1.5 Conditioning of specimens,26.1.6 Rate of voltage increase, and26.1.7 Size and material of electrodes used.SURFACE RESISTIVITY27. Significance and Use27.1 Surface resistivity is of value for determining thesuitability of a materia
31、l under severe 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 di
32、ffer from each other by at least one power of ten.28. Conditioning28.1 Use one or more of the following conditions (seePractice D6054):28.1.1 Condition 18/35/90,28.1.2 Condition 2/90, or28.1.3 Condition 2/130.29. Procedure29.1 Determine the surface resistivity in the conditioningatmosphere in accord
33、ance with Test Methods D257, using stripelectrodes as shown in Fig. number 3 of that test method.29.2 It is important that the specimens not be contaminatedduring the placement of the electrodes.29.3 Do not allow the specimens used for test to contactunclean surfaces and do not touch them without we
34、aring cleangloves.29.4 Before testing any film of questionable cleanliness,clean it in accordance with the manufacturers suggestions.29.5 Cut test specimens to a width of 25 mm (1 in.).29.6 Calculate resistivity by multiplying resistance valuesby the ratio of the specimen width to the distance betwe
35、enelectrodes.29.7 Use an electrification time of 1 min 6 5sat100Vdc6 5 V unless otherwise specified (see 24.1).30. Report30.1 Report all the items listed in Test Methods D257.31. Precision and Bias31.1 PrecisionThis test method has been in use for manyyears, but no information has been presented to
36、ASTM uponwhich to base a statement of precision. No activity has beenplanned to develop such information.31.2 BiasThis test method has no bias because the valuefor surface resistivity is determined solely in terms of this testmethod itself.VOLUME RESISTIVITY32. Significance and Use32.1 Refer to Test
37、 Methods D257.33. Test Specimen33.1 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 cau
38、se crazing orotherwise affect the test specimen.NOTE 6For films greater than 0.12 mm (5 mils) in thickness, a guardelectrode is usually required.34. Procedure34.1 Apply 100 V dc for 1 min unless otherwise specified.Measure the volume resistance in accordance with Test Meth-ods D257.35. Calculation35
39、.1 Calculate 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.36. Report36.1 Report all items listed in Test Methods D257.37. Precision and Bias37.1 PrecisionThis test method has been in
40、 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.37.2 BiasThis test method has no bias because the valuefor volume resistivity is determined solely in terms of this testmethod itself.
41、D2305 184RESISTANCE METHOD FOR MEASURING THETENDENCY TO CORRODE METALS38. Significance and Use38.1 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 possibl
42、e corrosive effect of 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 fi
43、lm.39. Procedure39.1 Determine the surface resistivity of the film in accor-dance with Section 29, with the following exceptions:39.1.1 Condition the specimens for 18 h at a relativehumidity of 96 6 2 % and 23 6 1C (73 6 2F). Satisfactorymeans of obtaining this relative humidity are described inPrac
44、tice D5032. Make at least 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 isdescribed in Test Methods D1000.40. Report40.1 Report the following
45、 information:40.1.1 Identification of the film,40.1.2 Width of the film,40.1.3 Number of measurements, and40.1.4 Median, minimum, and maximum resistance inmegohms.41. Precision and Bias41.1 PrecisionThis test method has been in use for manyyears, but no information has been presented to ASTM uponwhi
46、ch to base a statement of precision. No activity has beenplanned to develop such information.41.2 BiasThis test method has no bias because the valuefor surface resistivity is determined solely in terms of this testmethod itself.PERMITTIVITY AND DISSIPATION FACTOR42. Significance and Use42.1 See Test
47、 Methods D150.43. Electrodes43.1 See Test Methods D150.43.2 If tests are to be made over a range of temperatures,apply contacting electrodes to the specimens. For specimens 13m (0.5 mil) or more thick, sprayed-on conducting silver paintand evaporated gold and aluminum metals have been foundsatisfact
48、ory for many materials. Before using these, be certainthat the solvent in the paint or the environment of the vacuumchamber in which the metal evaporation is performed will notadversely affect the specimens.43.3 For tests on thin specimens, such as 5.1 m (0.2 mil),use the two fluid immersion methods
49、 at room temperaturewithout applying contacting electrodes (see Test MethodsD1531); with this method the permittivity is determinedwithout measuring the specimen thickness. For the two-fluidmethod, it is recommended that one fluid be air and the otherbe a dielectric fluid known to have no deteriorative effect onthe films electrical properties at least during the interval of thetest. Silicone fluid of 1 or 2 mm2/s (1 or 2-cSt) viscosity hasproven satisfactory for many films such as fluorinated ethylenepropylene (FEP), polyethylene (PE), polyethylene terep
