1、Designation: D 3420 08aStandard Test Method forPendulum Impact Resistance of Plastic Film1This standard is issued under the fixed designation D 3420; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numb
2、er in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the determination of resistanceof film to impact-puncture penetration. Knowledge of how theimpact energy is absorb
3、ed by the specimen while it is deform-ing under the impact loading, and the behavior of the specimenafter yielding, is not provided by this test. No provision is madefor nonambient temperatures in this test method.1.2 The values stated in SI units are to be regarded as thestandard.1.3 This standard
4、does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific hazardsstatements are g
5、iven in Section 7.NOTE 1There is no known ISO equivalent to this standard.2. Referenced Documents2.1 ASTM Standards:2D 618 Practice for Conditioning Plastics for TestingD 883 Terminology Relating to PlasticsD 1709 Test Methods for Impact Resistance of Plastic Filmby the Free-Falling Dart MethodD 192
6、2 Test Method for Propagation Tear Resistance ofPlastic Film and Thin Sheeting by Pendulum MethodD 4272 Test Method for Total Energy Impact of PlasticFilms By Dart DropD 6988 Guide for Determination of Thickness of PlasticFilm Test SpecimensE 177 Practice for Use of the Terms Precision and Bias inAS
7、TM Test MethodsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 DefinitionsDefinitions of terms relating to plastics nototherwise described in this test method shall be in accordancewith Terminology D 883.3.2 Definitions of Terms Spec
8、ific to This Standard:3.2.1 failure completion energythe energy necessary toinitiate failure plus the energy necessary to cause completerupture to the test specimen.3.2.2 failure initiated energythe energy necessary to be-gin failure of the test specimen.3.2.3 pendulum impact resistancethe resistanc
9、e to failureof plastic film is measured by loss in mechanical work capacitydue to the expenditure of kinetic energy by a pendulum.4. Summary of Test Method4.1 The energy necessary to burst and penetrate the centerof a specimen, mounted between two plates with a circularaperture, is measured by the l
10、oss in mechanical work-capacitydue to the expenditure of kinetic energy by a pendulum, therounded probe of which passes through the test specimen.Corrections for “toss factor” or kinetic energy imparted to thepuncture fragment of the test specimen are not made, as onlytiny masses are involved. The p
11、endulum head hits the speci-men with a maximum velocity of about 74 m/min and amaximum energy of about 5 J (50 cmkgf).5. Significance and Use5.1 Like other techniques to measure toughness, this testmethod provides a means to determine parameters of a materialat strain rates closer to some end-use ap
12、plications than pro-vided by low-speed uniaxial tensile tests. Dynamic tensilebehavior of a film is important, particularly when the film isused as a packaging material. The same uncertainties about1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct respons
13、ibility of Subcommittee D20.19 on Film and Sheeting.Current edition approved Nov. 1, 2008. Published November 2008. Originallyapproved in 1975. Last previous edition approved in 2008 as D 3420 - 08.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service
14、at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-29
15、59, United States.correlations with thickness that apply to other impact tests alsoapply to this test (see section 3.4 of Test Methods D 1709).Hence, no provision for rationalizing to unit thickness isprovided.Also, no provision is made for testing at non-ambienttemperatures.5.2 This test method inc
16、ludes two procedures, similar ex-cept with regard to sample size: Procedure A for 60-mmdiameter and Procedure B for 89-mm diameter (commonlycalled the “Spencer”). The data have not been shown relatableto each other.5.3 Several impact test methods are used for film. It issometimes desirable to know t
17、he relationships among testresults derived by different methods. A study was conducted inwhich four films made from two resins (polypropylene andlinear low-density polyethylene), with two film thicknesses foreach resin, were impacted using Test Methods D 1709 (MethodA), Test Method D 3420 (Procedure
18、s A and B), and TestMethod D 4272. The test results are shown in Appendix X2.Differences in results between Test Methods D 1709 andD 4272 are expected since Test Methods D 1709 representsfailure initiated energy while Test Method D 4272 is initiationplus completion energy. Some films have shown cons
19、istencywhen the initiation energy was the same as the total energy.This statement and the test data also appear in the significanceand appendixes sections of Test Methods of D 1709 andD 4272.6. Apparatus6.1 Tester,3having a heavy base plate (to be bolted downwhen the higher energy ranges are used),
20、housing, and frameupon which is located a free-swinging pendulum with animpact head. The dimensions for the impact heads for Proce-dures A and B are as follows:6.1.1 Procedure AHemispherical, having a smooth sur-face of 12.7-mm (0.5-in.) radius and 25.4-mm (1.0-in.) diam-eter, and6.1.2 Procedure BHa
21、ving a smooth surface of 12.7-mm(0.5-in.) radius, and 19.0-mm (0.75-in.) diameter, which whenreleased from the starting position punctures the material. Thespecimen is clamped between two plates with a circularaperture of 60 6 0.3-mm (2.362 6 0.012-in.) diameter in thecenter for Procedure A and 89 6
22、 0.5 mm (3.50 6 0.02 in.) forProcedure B. Several types of clamps are available on theSpencer testers: a slip-ring type, manual-tightening type withO-ring, and air-operated type with O-ring. The O-ring type,either manual or air-operated, is recommended to minimizeslippage of the test specimen. The a
23、ir-operated O-ring clampshall be the referee-type.6.1.3 Calibrated Dial, to record the energy necessary toburst and penetrate the specimen (a scale and pointer withindicating follower and attachable auxiliary weights to givesuitable energy scales). Four energy scales have been foundsuitable, 0.5, 1.
24、0, 2.5, and 5.0 J (5, 10, 25, and 50 cmkgf), forProcedure A through the use of attachable auxiliary weights.For Procedure B, a modified Elmendorf tester having acapacity of 1600 gf (3200 gf with auxiliary weight) is normallyused. Pendulums of 200, 400, and 800 gf are also available.Equivalent energy
25、 capacities for these force capacities are asfollows:gf J (cmkgf)200 0.169 (1.7)400 0.338 (3.4)800 0.675 (6.8)1600 1.35 (13.5)3200 2.70 (27)6.2 Micrometer, reading to 60.00025 mm (60.00001 in.)for measuring specimen thickness.6.3 Specimen Cutter.7. Hazards7.1 In Procedure A do not release the pendul
26、um manuallywhen the temperature chamber is in position unless the unit isplugged in and energized; otherwise the chamber doors will notopen and will be struck by the pendulum ball. In eitherprocedure, be sure that the hands are kept out of the pendulumpath when it is in the cocked position.8. Test S
27、pecimens8.1 Obtain samples that are of uniform thickness andconsistency, flat, free of defects, and representative of thematerial to be tested.NOTE 2Although the scope of this test method is for films sheeting#0.25 mm (#10 mils), samples up to 0.40 mm (15 mils) have beentested, representing the uppe
28、r limit imposed by the design of the clamp,without damage to the pendulum.8.2 From throughout the sample, cut at least five specimens,100-mm (4-in.) diameter circular, or 100 by 100-mm (4 by4-in.) square or larger if clamps require.9. Preparation of Apparatus9.1 Procedure A:9.1.1 Level the instrumen
29、t carefully, using the level locatedon the instrument (assuming the level has been properlymounted and calibrated).9.1.2 Attach the largest weight (for example, “50 cmkgf” or“5.0 J”).9.1.3 Adjust the auxiliary weights on the rear of the pendu-lum so the pendulum hangs vertically when free.9.1.4 Set
30、the pointer on Point P of the scale, and adjust thearm that moves the pointer so it just contacts the pointer in thisposition.9.1.5 Release the pendulum from its latched position andallow to swing freely (with no sample). The pointer shall cometo within one scale division of the zero point. If this
31、is not thecase, the bearing likely needs cleaning.9.1.6 Whenever the range of test is changed, the instrumentmust be reset so the “pointer pusher” is against the pointer withthe pointer at P and the pendulum hanging freely. This is doneby repositioning the auxiliary weights.9.1.7 Select the energy r
32、ange and attach the correct weightsto the pendulum. Do not use a higher range than is necessaryto ensure rupture of the film under test.3Atester of the ProcedureAtype is available from Testing Machines Inc. (TMI),2 Fleetwood Court, Ronkonkoma, NY 11779. A tester of the Procedure B type isavailable f
33、rom Thwing-Albert Instrument Co., 14 W. Collings Ave., West Berlin, NJ08091.D 3420 08a29.2 Procedure B:9.2.1 Locate the instrument on a level surface.9.2.2 Zero the instrument in accordance with Test MethodD 1922 if the instrument has a pointer, or refer to themanufacturers recommendations if it has
34、 a digital readout.9.2.3 Select the weight so that the scale readings do not fallon the extreme ends of the range when testing specimens.9.2.4 Slippage of the specimen in the clamp when it isstruck by the impact head is a recognized cause for testingerror. The condition of the clamp and its operatio
35、n must beinspected and prepared to minimize slippage.Any slippage thatoccurs can be detected by marking each specimen with a waxpencil near the clamp after it is installed in test position, and byobserving the marking after the test for any change of location.NOTE 3Acalibration discussion is given i
36、nAppendix X1 for the testerin Procedure A.10. Conditioning10.1 ConditioningCondition the test specimens at 23 62C (73.4 6 3.6F) and 50 6 10 % relative humidity for notless than 40 h prior to test in accordance with Procedure A ofPractice D 618 unless otherwise specified by agreement or therelevant A
37、STM material specification. In cases of disagree-ment, the tolerances shall be 61C (61.8F) and 65%relative humidity.10.2 Test ConditionsConduct the tests at 23 6 2C (73.46 3.6F) and 50 6 10 % relative humidity unless otherwisespecified by agreement or the relevant ASTM material speci-fication. In ca
38、ses of disagreement, the tolerances shall be 61C(61.8F) and 65 % relative humidity.11. Procedure11.1 Procedure A:11.1.1 Determine the thickness of the specimens to thenearest 0.00025 mm (0.01 mil), in accordance with TestMethods D 6988.11.1.2 Set the control switches properly.NOTE 4In the TMI instru
39、ment (Procedure A): power switch, ON;selector switch, MANUAL; temperature control switch (for ambienttemperature), OFF.11.1.3 Place a specimen in the specimen holder.11.1.3.1 Turn the knob and pull it outward to removepressure from the hinged plate of the specimen holder. Openthe specimen holder, pu
40、sh the knob forward, and turn it to exerta gripping pressure on the specimen.11.1.3.2 If the specimen has excessive curl, tape it inposition in the specimen holder.11.1.4 Set the pendulum to its latched position by raising itcompletely with the hand and then gently releasing it, makingcertain it eng
41、ages the latch. This movement ensures the properfunctioning of the relay which will open the temperaturechamber doors at the proper instant during the test.11.1.5 Place the specimen holder in the instrument andtighten it in place with the tightening knobs.11.1.6 Set the movable pointer to P on the g
42、raduated scale.11.1.7 For an ambient temperature test, the pendulum willrelease when the MANUAL button is pushed.11.1.8 After the swing, determine if the film specimenruptured. If not, record this fact. If so, read the position of themovable pointer on the appropriate scale (corresponding to theweig
43、hts used) and record this value in joules or centimetres-kilograms-force.NOTE 5It is wise to make trial tests, especially for thicker specimens,by dropping the pendulum from a partial arc, so as to avoid damage to thependulum (bending). If damage is suspected, the impact point shall bechecked for pr
44、oper centering by inserting a clear specimen in the holderand allowing the impact head to rest against it.11.1.9 Remove the tested specimen and test the remainingspecimens as described above.11.2 Procedure B:11.2.1 Determine the thickness of the specimens to thenearest 0.00025 mm (0.01 mil), in acco
45、rdance with TestMethods D 6988.11.2.2 Place a specimen in the specimen holder.11.2.3 Set the pendulum in its raised latched position. Zerothe indicator and mark the specimen as described in 9.2.4.11.2.4 Release the pendulum by pressing down firmly onthe latch stop. Be sure the pendulum completely cl
46、ears the stopas it swings, or it will be impeded and give a false reading. Theimpact head shall pass completely through the specimen. If itdoes not, a weight shall be added to the pendulum to providemore energy, or a thinner specimen shall be used.11.2.5 Catch the pendulum with the hand on its retur
47、n swingand reset it in the raised latched position.11.2.6 Record the scale reading.11.2.7 Remove the ruptured test specimen from the clamp.Observe the tested specimen for slippage. If slippage hasoccurred, the test shall be repeated using a new specimen. Testthe remaining specimens as described abov
48、e.12. Calculation12.1 For each specimen tested, calculate impact energy asfollows:12.1.1 For Procedure A:E 5scale reading in cmkgf!10.2(1)where E equals energy to rupture, J.12.1.2 For Procedure B:E 5 R/100! 3 C (2)where:E = energy to rupture, J,C = apparatus capacity, J (0.17, 0.34, 0.67, 1.35, or
49、2.7 J),andR = scale reading on the 0 to 100 scale.13. Report13.1 Report the following information:13.1.1 Complete identification of the sample,13.1.2 The capacity of the pendulum in joules (orcentimetres-kilogram-force) and procedure used (A or B,differing in sample size (see 5.2),D 3420 08a313.1.3 Total number of specimens tested per sample,13.1.4 The average impact strength in joules or centimetres-kilograms-force,13.1.5 The average thickness in micrometres or mils,13.1.6 If required, the calculated standard deviation of thevalues of the impact stre
