1、Designation: D1922 09D1922 15Standard Test Method forPropagation Tear Resistance of Plastic Film and ThinSheeting by Pendulum Method1This standard is issued under the fixed designation D1922; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r
2、evision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 This test
3、method2 covers the determination of the average force to propagate tearing through a specified length of plasticfilm or nonrigid sheeting after the tear has been started, using an Elmendorf-type tearing tester. Two specimens are cited, arectangular type, and one with a constant radius testing length
4、. The latter shall be the preferred or referee specimen.1.2 Because of (1) difficulties in selecting uniformly identical specimens, (2) the varying degree of orientation in some plasticfilms, and (3) the difficulty found in testing highly extensible or highly oriented materials, or both, the reprodu
5、cibility of the testresults may be variable and, in some cases, not good or misleading. Provisions are made in the test method to address obliquedirectional tearing which may be found with some materials.1.3 The values stated in SI units are to be regarded as standard. The values given in parenthese
6、s are for information only.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations pri
7、or to use. Specific precautionary statements are given in 13.1.NOTE 1Film has been arbitrarily defined as sheeting having nominal thickness not greater than 0.25 mm (0.010 in.).NOTE 2This standard is equivalent to ISO 6383-2.2. Referenced Documents2.1 ASTM Standards:3D618 Practice for Conditioning P
8、lastics for TestingD689 Test Method for Internal Tearing Resistance of Paper (Withdrawn 2009)4D1004 Test Method for Tear Resistance (Graves Tear) of Plastic Film and SheetingD4000 Classification System for Specifying Plastic MaterialsD5947 Test Methods for Physical Dimensions of Solid Plastics Speci
9、mensD6988 Guide for Determination of Thickness of Plastic Film Test SpecimensE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method2.2 ISO Standard:ISO 6383-2 PlasticsFilm and SheetingDetermination of Tear ResistancePart 2 Elmendorf Method51 This test metho
10、d is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.19 on Film, Sheeting, and MoldedProducts.Current edition approved May 1, 2009May 1, 2015. Published June 2009June 2015. Originally approved in 1961. Last previous edition approved in 20
11、082009 asD1922 - 08.D1922 - 09. DOI: 10.1520/D1922-09.10.1520/D1922-15.2 This test method has been adapted from TAPPI Standard Method T 414M-49, Internal Tearing Resistance of Paper. In testing certain plastic films, problems ofreproducibility and interpretation of results are encountered which requ
12、ire special treatment to make the test method of most value. This test method is revised here specificallyfor use with plastic film and thin sheeting. For more complete explanation of certain aspects of the equipment, its calibration and adjustment, refer to TAPPI Standard MethodT 414M-49.The follow
13、ing additional references may be of interest in connection with this test method:Painter, E. V., Chu, C. C., and Morgan, H. M., “Testing Textiles on the Elmendorf Tear Tester,” Textile Research Journal, Vol XX, No. 6, June 1950, pp. 410417.Elmendorf, A., “Strength Test for Paper,” Paper, Vol 26, Apr
14、il 21, 1920, p. 302.3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. ForAnnual Book ofASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.4 The last approved version of this histori
15、cal standard is referenced on www.astm.org.5 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036.10036, http:/www.ansi.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what c
16、hanges have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the of
17、ficial document.*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 States13. Summary of Test Method3.1 The force in grams required to propagate tearing across a film or sheeting s
18、pecimen is measured using a precisely calibratedpendulum device. Acting by gravity, the pendulum swings through an arc, tearing the specimen from a precut slit. The specimenis held on one side by the pendulum and on the other side by a stationary member. The loss in energy by the pendulum is indicat
19、edby a pointer. The scale indication is a function of the force required to tear the specimen.4. Significance and Use4.1 This test method is of value in ranking relative tearing resistance of various plastic films and thin sheeting of comparablethickness. Experience has shown the test to have its be
20、st reliability on relatively less extensible films and sheeting. Variableelongation and oblique tearing effects on the more extensible films preclude its use as a precise production-control tool for thesetypes of plastics. This test method should be used for specification acceptance testing only aft
21、er it has been demonstrated that thedata for the particular material are acceptably reproducible. This test method should be used for service evaluation only after itsusefulness for the particular application has been demonstrated with a number of different films.4.2 This test method has been widely
22、 used as one index of the tearing resistance of plastic film and thin sheeting used inpackaging applications. While it mayis not always be possible to correlate film tearing data with its other mechanical or toughnessproperties, the apparatus of this test method provides a controlled means for teari
23、ng specimens at straining rates approximatingsome of those found in actual packaging service.4.3 Due to orientation during their manufacture, plastic films and sheeting frequently show marked anisotropy in their resistanceto tearing. This is further complicated by the fact that some films elongate g
24、reatly during tearing, even at the relatively rapid ratesof loading encountered in this test method. The degree of this elongation is dependent in turn on film orientation and the inherentmechanical properties of the polymer from which it is made.These factors make tear resistance of some films repr
25、oducible betweensets of specimens to 65 % of the mean value, while others maypotentially show no better reproducibility than 650 %.4.4 Data obtained by this test method may supplement that from Test Method D1004, wherein the specimen is strained at a rateof 50 mm (2 in.) per minute. However, specime
26、n geometry and testing speed of the two test methods are dissimilar. The rate oftearing in this test method, while varying as a function of resistance to tear, is in the range from 7.6 to 46 m (300 to 1800 in.)/min.4.5 There is not a direct, linear relationship between tearing force and specimen thi
27、ckness. Data from this test method areexpressed as tearing force in millinewtons (or grams-force, if desired), with specimen thickness also reported. But sets of data fromspecimens of dissimilar thickness are usually not comparable. Therefore, only data at the same thickness can be is compared.4.6 F
28、or many materials, there may be a specification that requires the use of this test method, but with some proceduralmodifications that take precedence when adhering to the specification. Therefore, it is advisable to refer to that materialspecification before using this test method. Table 1 of Classi
29、fication System D4000 lists the ASTM materials standards thatcurrently exist.5. Apparatus5.1 Pendulum Impulse-Type Testing Apparatus, 6 consisting of the following:5.1.1 Stationary Clamp.5.1.2 Movable Clamp, carried on a pendulum, preferably formed by a sector of a wheel or circle, free to swing on
30、a ball bearingor other substantially frictionless bearing.5.1.3 Stop Catch, for holding the pendulum in a raised position and for releasing it instantaneously.5.1.4 Indicating Device, for registering the maximum arc through which the pendulum swings when released. The pendulumshall carry a circumfer
31、ential scale, graduated from 0 to 100 % of the machine capacity so as to read against the pointer the averageforce required to tear a specimen 43 mm (1.7 in.). The option to replace the pointer and scale may be replaced by an electronicdigital readout. readout is available. Digital readouts are avai
32、lable which will give test results directly in millinewtons, directly ingrams-force, or in percent of pendulum capacity. With the pendulum in its initial position ready for test, separate the two clampsby an interval of 2.54 mm (0.10 in.). So align them that the specimen clamped in them lies in a pl
33、ane perpendicular to the planeof oscillation of the pendulum with the edges of the jaws gripping the specimen in a horizontal line, a perpendicular to whichthrough the axis of suspension of the pendulum is 102.7 6 0.05 mm (4.044 6 0.002 in.) in length and makes an angle of 27.5with the plane of the
34、film specimen. The clamping surface in each jaw shall be at least 25.4 mm (1 in.) in width and at least 12.7mm (0.5 in.) in depth.5.1.5 CapacityInstruments of several capacities, 1960, 3920, 7840, 15 600, 31 360, 62 720 mN (200, 400, 800, 1600, 3200,6400 gf), and perhaps others are available. These
35、capacities can be are achieved by individual instruments, interchangeablependulum sectors, or augmenting weights.6 The sole source of supply of the apparatus known to the committee at this time is Thwing-Albert Instrument Co., Philadelphia, PA19144. If you are aware of alternativesuppliers, please p
36、rovide this information to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the responsible technicalcommittee,1 which you may attend.D1922 1525.2 Template, Die, or Shear-Type Cutter6,7, for cutting specimens.5.3 Razor Blades, single-edged, for cuttin
37、g specimens where a template is used.5.4 Thickness-Measuring DeviceMicrometer, or other suitable thickness gauge for measuring the thickness of test specimensin accordance with Test Methods D5947 or Guide D6988 as appropriate.6. Test Specimens6.1 Test specimens shall be cut using a die or template,
38、as shown in Fig. 1, to form a constant-radius testing length. This shallbe the preferred or referee specimen type since its geometry is intended to compensate to some degree for the problem of obliquetearing (Note 3 and Note 4). Alternatively, specimens shall be cut to form a rectangle 76 mm (3 in.)
39、 or more in width by 63 mm(2.5 in.) in length and plainly marked to denote intended direction of tear. The 63-mm specimen dimension shall be the directionof tear. Two sets of specimens shall be cut from each sample so that their sides are parallel to (1 ) the machine direction and (2)the transverse
40、direction, respectively, of the material being tested. Enough specimens shall be cut in each direction to provide aminimum of ten tear strength determinations.NOTE 3Specimens having constant-radius testing lengths are designed to correct for oblique directional tearing encountered in certain anisotr
41、opic,elastomeric films, and nonrigid sheeting. For purposes of specimen selection, oblique tearing is defined as tearing in a curved or straight line that deviatesmore than 9.5 mm (38 in.) from the vertical line of intended tear.NOTE 4Certain film and sheeting specimens showing oblique tearing may y
42、ield data of poor reproducibility because the axis of maximum orientationvaries as much as 30 from the nominal machine direction. When this is suspected, the sample may be examined by crossed Polaroid plates to determinethis direction of maximum orientation and the specimens cut along the axis of an
43、isotropy for testing parallel and normal to it.6.2 Where a metal template is used, the film or sheeting shall be placed on a hard surface. The template shall be held over itand the specimens cut out using a single-edged razor blade.6.3 When the specimen is cut out, a slit 20 mm (0.8 in.) deep may is
44、 to be made at the center of the edge perpendicular to thedirection to be tested. This leaves exactly 43 mm (1.7 in.) of tearing length between the end of the slit and the opposite edge ofthe specimen. This slit may be cut Alternatively, cut this slit into the specimen after it has been placed in th
45、e testing apparatus.NOTE 5The pendulum apparatus may be fitted with a sharp-loaded knife to make this slit in the specimen after it has been clamped in the apparatus.The action of the knife must be such as to make a clean slit exactly 20 mm (0.8 in.) into the specimen from the edge.6.4 The test spec
46、imens shall conform to the dimensions in Fig. 1 for the constant-radius specimen or to the dimensions notedin 6.1 for rectangular specimens and shall not vary more than 0.5 % from these dimensions.7. Adjustment of Apparatus7.1 Pendulum Friction:7 The TA63 Sample Cutter, Catalog No. 98, available fro
47、m the Thwing-Albert Instrument Co., Philadelphia, PA 19144, has been found satisfactory for cutting specimens.Tolerance = 60.050 mm (0.002 in.)FIG. 1 Die or Template for Constant-Radius Test SpecimenD1922 1537.1.1 Older InstrumentsTo check the pendulum swing for freedom from excess friction, level t
48、he apparatus and draw a pencilline on the base or stop mechanism 25.4 mm (1 in.) to the right of the edge of the sector stop. With the sector raised to its initialposition and the pointer set against its stop, on releasing the sector and holding the stop down, the sector shouldshall make at least20
49、complete oscillations before the edge of the sector that engages with the stop no longer passes to the left of the pencil line.Otherwise, oil and adjust the bearing.7.1.2 Newer InstrumentsIn recent years, a new type of frictionless bearing made of synthetic material has been used. Thisbearing will not necessarily allow the pendulum sector to make 20 complete oscillations as the older one did. This does not meanthat there is excess friction in the pendulum swing. These newer bearings should not be oiled. Consult the instructions suppliedwith the instrument for guid
