1、Designation: D 3420 95 (Reapproved 2002)Standard 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
2、 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 This test method covers the determination of resistanceof film to impact-puncture penetration. Knowledge of how theimpact
3、 energy is absorbed 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
4、.3 This standard 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 hazard
5、sstatements are given in Section 7.NOTE 1There is no similar or equivalent ISO standard.2. Referenced Documents2.1 ASTM Standards:D 374 Test Methods for Thickness of Solid Electrical Insu-lation2D 618 Practice for Conditioning Plastics and ElectricalInsulating Materials for Testing3D 883 Terminology
6、 Relating to Plastics3D 1709 Test Methods for Impact Resistance of Plastic Filmby the Free-Falling Dart Method3D 1922 Test Method for Propagation Tear Resistance ofPlastic Film and Thin Sheeting by Pendulum Method3D 4272 Test Method for Total Energy Impact of PlasticFilms by Dart Drop4E 177 Practice
7、 for Use of the Terms Precision and Bias inASTM Test Methods5E 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method53. Terminology3.1 DefinitionsDefinitions of terms relating to plastics nototherwise described in this test method shall be in accordancewith
8、Terminology D 883.3.2 Definitions of Terms Specific 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 specime
9、n.3.2.3 pendulum impact resistancethe resistance 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 plate
10、s with a circularaperture, is measured by the loss 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 n
11、ot made, as onlytiny masses are involved. The pendulum 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 ma
12、terialat strain rates closer to some end-use applications 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 aboutcorrelations with thickness that apply to other impact
13、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.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct r
14、esponsibility of Subcommittee D20.19 on Film and Sheeting.Current edition approved June 15, 1995. Published August 1995. Originallypublished as D 3420 75. Last previous edition D 3420 94.The current edition includes the addition of Note 1 and Section 15, Keywords.2Annual Book of ASTM Standards, Vol
15、10.01.3Annual Book of ASTM Standards, Vol 08.01.4Annual Book of ASTM Standards, Vol 08.02.5Annual Book of ASTM Standards, Vol 14.02.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 This test method includes two procedures, similar
16、 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 the relationships among testre
17、sults 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 (Procedures A and B), and TestMethod D
18、4272. The test results are shown in Appendix X2.Differences in results between Test Methods D 1709 andD 4272 may be expected since Test Methods D 1709 representsfailure initiated energy while Test Method D 4272 is initiationplus completion energy. Some films may show consistencywhen the initiation e
19、nergy is the same as the total energy. Thisstatement and the test data also appear in the significance andappendixes sections of Test Methods of D 1709 and D 4272.6. Apparatus6.1 Tester,6having a heavy base plate (to be bolted downwhen the higher energy ranges are used), housing, and frameupon which
20、 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 BHaving a smooth surface of 12.
21、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 0.5 mm (3.50 6 0.02 in.) fo
22、rProcedure 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 air-operated O-ring clampshal
23、l 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, 1.0, 2.5, and 5.0 J (5, 10, 25
24、, 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 capacities for these force
25、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 pendulum manuallywhen the temperat
26、ure 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 Specimens8.1 Obtain samples t
27、hat 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 upper limit imposed by the desig
28、n 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 instrument carefully, using the level
29、 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 the pointer on Point P of th
30、e 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 shouldcome to within one scale division of the zero point. If this is notthe case, the bearing
31、 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 range and attach the correct
32、 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 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 rec
33、ommendations 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 testing specimens.6A tester of the Procedure A type is available from Testing Machines Inc. (TMI),400 Bayview Ave., Amityville, Long Island, NY 11701. A tester
34、 of the Procedure Btype is available from Thwing-Albert Instrument Co., 10960 Dutton Road, Phila-delphia, PA 19154.D 3420 95 (2002)29.2.4 Slippage of the specimen in the clamp when it isstruck by the impact head is a recognized cause for testingerror. Slippage may be minimized by giving adequate att
35、entionto the condition of the clamp and its operation. Any slippagethat occurs can be detected by marking each specimen with awax pencil near the clamp after it is installed in test position,and by observing the marking after the test for any change oflocation.NOTE 3A calibration discussion is given
36、 in Appendix X1 for the testerin Procedure A.10. Conditioning10.1 Condition the test specimens at 23 6 2C (73.4 63.6F) and 50 6 5 % relative humidity in accordance withProcedure A of Practice D 618, for those tests where condi-tioning is required. In cases of disagreement, the tolerancesshall be 61C
37、 (61.8F) and 62 % 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 374.11.1.2 Set the control switches properly.NOTE 4In the TMI instrument (Procedure A): power switch, ON;selector sw
38、itch, 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, push the knob forward, and turn it to exerta gripp
39、ing 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 engages the latch. This movement ensures the proper
40、functioning 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 graduated scale.11.1.7 For an ambient temperature
41、 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 theweights used) and record this value in joules or cen
42、timetres-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 should bechecked for proper centering by inserting a clear specimen in
43、 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 accordance with TestMethods D 374.11.2.2 Place a sp
44、ecimen 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 clears the stopas it swings, or it will be impeded
45、 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 return swingand reset it in the raised latched positi
46、on.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 should be repeated using a new specimen.Test the remaining specimens as described above.12. Calculation12.1 For each specimen tested,
47、 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 2.7 J),andR = scale reading on the 0 to 100 sca
48、le.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 ave
49、rage 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 strengths of the specimens of 13.1.3, and13.1.7 Temperature of specimen environment, degrees Cel-sius.D 3420 95 (2002)314. Precision14.1 For Procedure A, for round-robin results7on fivematerials in six laboratories, the within-laboratory standarddeviation is estimated to be 0.11 J (1.1 cmkgf), and thebetween-laboratory standard deviation (including within-laborato
