1、Designation: D2305 10D2305 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 revisi
2、on. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope Scope*1.1 These test methods cover the testing of homogeneous organic polymer films not over 2.4 mm (95 mils) thick that are to beus
3、ed for electrical insulation.1.2 These test methods are not necessarily applicable to testing films in combinations with a coating, another film, or with othertypes of substrate, such as fabrics or papers.1.3 The values stated in SI units are the standard. The values in parentheses are provided for
4、information only.1.4 The procedures appear in the following sections:Procedure SectionsConditioning 5 and 6Conditioning 6 and 7Dielectric Breakdown Voltage therefore, the specimen needs to be in the stated conditioning environment when thetest is being performed. When the test is performed in a diff
5、erent environment, note these conditions and the time of exposure tothis new environment.7. Procedure7.1 Unless otherwise specified in the individual test methods, test the specimens in the Standard Laboratory Atmosphere 23 62C, 50 6 5 % R.H. prescribed in Practice 10 % R.H.D6054.THICKNESS8. Signifi
6、cance and Use8.1 The determination of film thickness is frequently necessary to ensure (1) the satisfactory production of electrical equipment,and (2) the maintenance of desired electrical properties of the film during the use of the electrical equipment. Some properties, suchas dielectric strengths
7、, vary with the thickness of the material; other properties, such as permittivity, cannot be calculated withouta proper determination of thickness unless special techniques are used.9. Procedure9.1 Use Method C of Test Methods D374 for this measurement, with the apparatus modified as follows: Use a
8、presser foot of6.25 6 0.05 mm (250 6 1 mil) diameter, and an anvil surface, upon which the specimen rests, of at least 50-mm (2-in.) diameter.Apply a force of 0.84 6 0.2 N (3 6 0.75) ozf to the specimen. Take ten measurements, equally spaced throughout the specimen.10. Report10.1 Report the average,
9、 maximum, and minimum thicknesses to the nearest 0.5 m (0.02 mil) for specimens thinner than 50m (2 mils) and to the nearest 1 m (0.04 mil) for specimens 50 m (2 mils) or more in thickness.11. Precision and Bias11.1 PrecisionAformal round robin test in accordance with Practice E691 has not been cond
10、ucted. Persons familiar with thismethod have determined that two test results can be expected (with a probability of 95 %) to agree within 3 %. Each test resultis the average of 10 thickness readings taken on a single sample of polyimide film in one laboratory in which a multiple numberof operators
11、used the same apparatus.11.2 BiasThis test method has no bias because the value for thickness is determined solely in terms of this test method.TENSILE PROPERTIES12. Procedure12.1 Use Method A of Test Methods D882. Report data only for the specific tests required by a specification.12.2 Prepare five
12、 specimens in each of the two principal directions, each 12 by 200 mm (0.5 by 8 in.).12.3 Unless otherwise stated, measure the tensile strength and tensile elongation, with initial jaw separation of 100 6 2 mm(4.06 0.08 in.) and rate of jaw separation of 50 6 2 mm (2 6 0.08 in.)/min.12.4 For each sp
13、ecimen, record the thickness and width prior to the application of the tensile force. Use these values to calculatethe tensile strength for each specimen. Report the tensile strength in MPa (lbf/in.2).STRAIN RELIEF13. Significance and Use13.1 The strain relief test gives an indication of the dimensi
14、onal changes that have the potential to occur when a film is exposedto elevated temperatures during a manufacturing process or while in service.14. Apparatus14.1 Ovens, shall be of a forced-convection type capable of maintaining the specified temperature6 5C.temperature 65C.14.2 Scale, graduated in
15、0.25-mm (0.01-in.) divisions with a total length of at least 300 mm (12 in.).D2305 18315. Test Specimen15.1 Prepare test specimens 25 mm (1 in.) wide and at least 300 mm (12 in.) long. When sheets or rolls are greater than 300mm wide, also cut specimens in the transverse direction.16. Conditioning16
16、.1 Condition test specimens in accordance with Section 67 before the initial and final measurements are made.17. Procedure17.1 Mark gage lines on five specimens approximately 25 mm (1 in.) in from the ends of the specimen at a gage distance of250 mm (10.0 in.). Determine the initial gage distance by
17、 measuring both edges of each specimen. Hang the specimen freely inthe oven at the time and temperature specified for the material. Determine the final gage distance by measurement afterconditioning.17.1.1 Use a marking technique that does not affect the properties or dimensions of the material.17.1
18、.2 Adjust the air flow in the oven so that the specimens do not whip.18. Calculation18.1 Calculate the liner dimensional change as follows:Linear change,%5Dt 2Dv!/Dv# 3100 (1)where:Dt = final dimensions, in. (mm), andDv = original dimension, in. (mm).A negative value denotes shrinkage, and a positiv
19、e value indicates expansion.18.2 Average the values obtained for each direction.19. Report19.1 Report the following information:19.1.1 Identification of the material tested,19.1.2 Test conditions (time and temperature), including the conditioning of the test specimens,19.1.3 Average percentage linea
20、r change and maximum deviations, in both machine and transverse directions of the film, and19.1.4 Any curl at the edges or other visual defects.20. Precision and Bias20.1 PrecisionThis test method has been in use for many years, but no information has been presented to ASTM upon whichto base a state
21、ment of precision. No activity has been planned to develop such information.20.2 BiasThis test method has no bias because the value for strain relief is determined solely in terms of this test method itself.DIELECTRIC BREAKDOWN VOLTAGE AND DIELECTRIC STRENGTH21. Significance and Use21.1 The dielectr
22、ic breakdown voltage and dielectric strength of a film is an indication of its ability to withstand electric stress.This value needs to be used primarily as an indication of quality and for comparison of different lots or types of the same material.Secondarily, this value will potentially be useful
23、as a design criterion, particularly when considering short term exposures,providing that sufficient experience has been gained to give an adequate correlation between this test and the proposed end uses.21.2 Unless special precautions are taken, these test results will potentially be just a measure
24、of the quality of the electrodesurfaces and the electrical apparatus. This is especially true with thinner films.21.3 For further details on the significance of this test, refer to Test Method D149.22. Apparatus22.1 Use apparatus that conforms to that specified in Test Method D149, including the 25-
25、mm (1-in.) diameter electrodesdescribed therein.As an exception, the 6.4-mm (14-in.) diameter electrodes are permitted where only narrow tape is available; andnote such exceptions in the report. For further details on electrodes refer to the electrode section of Test Method D149.NOTE 2Tests made wit
26、h different size electrodes are not necessarily comparable. In many cases, a change in electrode size can make a significantdifference in test results. Take care to keep electrodes parallel, clean, and free of pits.23. Test Specimen23.1 Test clean specimens only. Surface contamination can form dents
27、 when the electrodes are applied to the specimen or canalter the electrical field pattern, or both, to give erroneous results.D2305 184NOTE 3To help prevent the specimen from becoming contaminated during the test, it is recommended that the tests be made in a clean, air-conditionedroom supplied with
28、 filtered air.24. Procedure24.1 Determine the dielectric breakdown voltage in air and dielectric strength in accordance with Test Method D149, and inaccordance with the applicable sections of this test method. Unless otherwise specified, make ten breakdown measurements,equally spaced throughout the
29、specimen.NOTE 4When testing films in a medium other than air, it is possible that different results will be obtained.(WarningLethal voltages are a potential hazard during the performance of this test. It is essential that the test apparatus, andall associated equipment electrically connected to it,
30、be properly designed and installed for safe operation. Solidly ground allelectrically conductive parts which it is possible for a person to contact during the test. Provide means for use at the completionof any test to ground any parts which were at high voltage during the test or have the potential
31、 for acquiring an induced chargeduring the test or retaining a charge even after disconnection of the voltage source. Thoroughly instruct all operators as to thecorrect procedures for performing tests safely. When making high voltage tests, particularly in compressed gas or in oil, it ispossible for
32、 the energy released at breakdown to be suffcient to result in fire, explosion, or rupture of the test chamber. Designtest equipment, test chambers, and test specimens so as to minimize the possibility of such occurrences and to eliminate thepossibility of personal injury. If the potential for fire
33、exists, have fire suppression equipment available.)25. Application of Voltage25.1 Unless otherwise specified, use the short-time test method with a rate of rise of 500 V/s.26. Report26.1 Unless otherwise specified, report the following information:26.1.1 Average breakdown voltage,26.1.2 Average thic
34、kness of breakdown specimens,26.1.3 Average, maximum, and minimum dielectric 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.
35、1 Surface resistivity is of value for determining the suitability of a material under severe service conditions such as hightemperature and high humidity. Its primary use needs to be as an indication of quality and for comparison of different lots or typesof the same material. Secondarily, it is pos
36、sible that this test will be used to classify materials into broad groups that differ fromeach other by at least one power of ten.28. Conditioning28.1 Use one or more of the following conditions (see Practice D6054):28.1.1 Condition 18/35/90,28.1.2 Condition 2/90, or28.1.3 Condition 2/130.29. Proced
37、ure29.1 Determine the surface resistivity in the conditioning atmosphere in accordance 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 contaminated during the placement of the electrodes.29.3 Do not allow the
38、specimens used for test to contact unclean surfaces and do not touch them without wearing clean gloves.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
39、 multiplying resistance values by the ratio of the specimen width to the distance between electrodes.29.7 Use an electrification time of 1 min 6 5 s at 100 V dc 6 5 V unless otherwise specified (see 23.124.1).30. Report30.1 Report all the items listed in Test Methods D257.D2305 18531. Precision and
40、Bias31.1 PrecisionThis test method has been in use for many years, but no information has been presented to ASTM upon whichto base a statement of precision. No activity has been planned to develop such information.31.2 BiasThis test method has no bias because the value for surface resistivity is det
41、ermined solely in terms of this test methoditself.VOLUME RESISTIVITY32. Significance and Use32.1 Refer to Test Methods D257.33. Test Specimen33.1 Prepare five specimens by depositing a 25-mm (1-in.) diameter electrode of silver conductive paint or evaporated metalon each side of the film. Take speci
42、al care so that the circles on the two sides are in register.NOTE 5Use a silver paint whose solvent will not cause crazing or otherwise affect the test specimen.NOTE 6For films greater than 0.12 mm (5 mils) in thickness, a guard electrode is usually required.34. Procedure34.1 Apply 100 V dc for 1 mi
43、n unless otherwise specified. Measure the volume resistance in accordance with Test MethodsD257.35. Calculation35.1 Calculate the volume resistivity in accordance with Test Methods D257 except that, where no guard electrode is used, thearea is based on the 25-mm (1-in.) diameter electrode.36. Report
44、36.1 Report all items listed in Test Methods D257.37. Precision and Bias37.1 PrecisionThis test method has been in use for many years, but no information has been presented to ASTM upon whichto base a statement of precision. No activity has been planned to develop such information.37.2 BiasThis test
45、 method has no bias because the value for volume resistivity is determined solely in terms of this testmethod itself.RESISTANCE METHOD FOR MEASURING THE TENDENCY TO CORRODE METALS38. Significance and Use38.1 Severe electrolytic corrosion has the potential to cause open circuit failures, leakage curr
46、ent paths, or weak pitted wires.The resistance test method is of value as an indirect indication of the possible corrosive effect of a film on metals under conditionsof high humidity when, and if, subjected to an electrical potential. While other factors also are of importance in controlling metalco
47、rrosion, the total amount of electrolytic corrosion of the metal is proportional to the currents carried by the film.39. Procedure39.1 Determine the surface resistivity of the film in accordance with Section 2829, with the following exceptions:39.1.1 Condition the specimens for 18 h at a relative hu
48、midity of 966 96 6 2 % and 23 6 1C (73 6 2F). Satisfactory meansof obtaining this relative humidity are described in Practice D5032. Make at least five determinations for surface resistivity at thisenvironmental condition using an electrification time of 15 s and a voltage of 100 to 130 V dc.NOTE 7A
49、pparatus found satisfactory for these measurements is described in Test Methods D1000.40. Report40.1 Report the following 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 in megohms.D2305 18641. Precision and Bias41.1 PrecisionThis test method has been in use for many years, but no information has been presented to ASTM upon whichto base a statement of precision. No activity has been planned to develop such information.41.2 BiasThis test method has
