1、Designation: D3420 14Standard Test Method forPendulum Impact Resistance of Plastic Film1This standard is issued under the fixed designation D3420; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number
2、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 absorbed
3、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 doe
4、s 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 give
5、n in Section 7.NOTE 1There is no known ISO equivalent to this standard.2. Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD883 Terminology Relating to PlasticsD1709 Test Methods for Impact Resistance of Plastic Filmby the Free-Falling Dart MethodD1922 Test
6、Method for Propagation Tear Resistance ofPlastic Film and Thin Sheeting by Pendulum MethodD4272 Test Method for Total Energy Impact of Plastic FilmsBy Dart DropD6988 Guide for Determination of Thickness of Plastic FilmTest SpecimensE177 Practice for Use of the Terms Precision and Bias inASTM Test Me
7、thodsE691 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 D883.3.2 Definitions of Terms Specific to This
8、 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 beginfailure of the test specimen.3.2.3 pendulum impact resistancethe resistance to failureof
9、 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 loss in mechani
10、cal 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 pendulum head h
11、its 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 applications tha
12、n 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 aboutcorrelations with thickness that apply to other impact tests alsoapply to this test (see section 3.4 of Test Methods
13、 D1709).Hence, no provision for rationalizing to unit thickness isprovided.Also, no provision is made for testing at non-ambienttemperatures.5.2 This test method includes two procedures, similar ex-cept with regard to sample size: Procedure A for 60-mmdiameter and Procedure B for 89-mm diameter (com
14、monlycalled the “Spencer”). The data have not been shown relatableto each other.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.19 on Film, Sheeting, andMolded Products.Current edition approved Dec. 1, 2014. Published
15、December 2014. Originallyapproved in 1975. Last previous edition approved in 2008 as D3420 08a. DOI:10.1520/D3420-14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to
16、 the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.3 Several impact test methods are used for film. It issometimes
17、 desirable to know the 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 D1709 (MethodA), Test Metho
18、d D3420 (Procedures A and B), and TestMethod D4272. The test results are shown in Appendix X2.Differences in results between Test Methods D1709 and D4272are expected since Test Methods D1709 represents failureinitiated energy while Test Method D4272 is initiation pluscompletion energy. Some films ha
19、ve shown consistency whenthe initiation energy was the same as the total energy. Thisstatement and the test data also appear in the significance andappendixes sections of Test Methods of D1709 and D4272.6. Apparatus6.1 Tester,3having a heavy base plate (to be bolted downwhen the higher energy ranges
20、 are used), 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.)diameter, which when r
21、eleased from the starting positionpunctures the material. The specimen is clamped between twoplates with a circular aperture of 60 6 0.3-mm(2.362 6 0.012-in.) diameter in the center.6.1.2 Procedure BHaving a smooth surface of 12.7-mm(0.5-in.) radius, and 19.0-mm (0.75-in.) diameter, which whenreleas
22、ed from the starting position punctures the material. Thespecimen is clamped between two plates with a circularaperture of 89 6 0.5 mm (3.50 6 0.02 in.). Several types ofclamps are available on the Spencer testers: a slip-ring type,manual-tightening type with O-ring, and air-operated type withO-ring
23、. The O-ring type, either manual or air-operated, isrecommended to minimize slippage of the test specimen. Theair-operated O-ring clamp shall be the referee-type.6.1.3 Calibrated Dial or Digital Readout, to record theenergy necessary to burst and penetrate the specimen (a scaleand pointer with indic
24、ating follower and attachable auxiliaryweights to give suitable energy scales). Four energy scaleshave been found suitable, 0.5, 1.0, 2.5, and 5.0 J (5, 10, 25, and50 cmkgf), for Procedure A through the use of attachableauxiliary weights. For Procedure B, a modified Elmendorftester having a capacity
25、 of 1600 gf (3200 gf with auxiliaryweight) is normally used. Pendulums of 200, 400, and 800 gfare also available. Equivalent energy capacities for these forcecapacities are as follows: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
26、.00025 mm (60.00001 in.)for measuring specimen thickness.6.3 Specimen Cutter.7. Hazards7.1 In Procedure A do not release the pendulum 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 pen
27、dulum ball. In eitherprocedure, be sure that the hands are kept out of the pendulumpath when it is in the cocked position.8. Test Specimens8.1 Obtain samples that are of uniform thickness andconsistency, flat, free of defects, and representative of thematerial to be tested.NOTE 2Although the scope o
28、f this test method is for films sheeting0.25 mm (10 mils), samples up to 0.40 mm (15 mils) have been tested,representing the upper limit imposed by the design of the clamp, withoutdamage to the pendulum.8.2 From throughout the sample, cut at least five specimens,100-mm (4-in.) diameter circular, or
29、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 instrument 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”
30、 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 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 p
31、osition andallow to swing freely (with no sample). The pointer shall cometo within one scale division of the zero point. If this 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 w
32、iththe pointer at P and the pendulum hanging freely. This is doneby repositioning the auxiliary weights.9.1.7 Select the energy range and attach the correct weightsto the pendulum. Do not use a higher range than is necessaryto ensure rupture of the film under test.9.2 Procedure B:9.2.1 Locate the in
33、strument on a level surface.9.2.2 Zero the instrument in accordance with Test MethodD1922 if the instrument has a pointer, or refer to the manu-facturers recommendations if it has a digital readout.9.2.3 Select the weight so that the scale readings do not fallon the extreme ends of the range when te
34、sting 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 operation must be3Atester of the ProcedureAtype is available from Testing Machines Inc. (TMI),2 Fleetwood Court, Ronkonkoma, NY 1
35、1779. A tester of the Procedure B type isavailable from Thwing-Albert Instrument Co., 14 W. Collings Ave., West Berlin, NJ08091.D3420 142inspected 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
36、in test position, and byobserving the marking after the test for any change of location.NOTE 3Acalibration discussion is given in Appendix X1 for the testerin Procedure A.10. Conditioning10.1 ConditioningCondition the test specimens in accor-dance with Procedure A of Practice D618 unless otherwisesp
37、ecified by agreement or the relevant ASTM material speci-fication. In cases of disagreement, 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 relev
38、ant ASTM material speci-fication. In cases 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 D6988.11.1.2 Set the control swi
39、tches properly.NOTE 4In the TMI instrument (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 specim
40、en holder. Openthe specimen holder, push 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 gen
41、tly releasing it, makingcertain it engages 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
42、 Set the movable pointer to P on the graduated 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 appro
43、priate scale (corresponding to theweights 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, t
44、he impact point shall bechecked for proper 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 the
45、nearest 0.00025 mm (0.01 mil), in accordance with TestMethods D6988.11.2.2 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 sto
46、p. Be sure the pendulum completely clears 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 th
47、e pendulum with the hand on its return 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
48、remaining specimens as described above.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 cap
49、acity, J (0.17, 0.34, 0.67, 1.35, or 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),13.1.3 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 th
