ASTM D1004-2008 Standard Test Method for Tear Resistance (Graves Tear) of Plastic Film and Sheeting.pdf

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1、Designation: D 1004 08Standard Test Method forTear Resistance (Graves Tear) of Plastic Film and Sheeting1This standard is issued under the fixed designation D 1004; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r

2、evision. 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 Department of Defense.1. Scope*1.1 This test method2covers the determination

3、of the tearresistance of flexible plastic film and sheeting at very low ratesof loading, 51 mm (2 in.)/min. and is designed to measure theforce to initiate tearing. The specimen geometry of this testmethod produces a stress concentration in a small area of thespecimen. The maximum stress, usually fo

4、und near the onset oftearing, is recorded as the tear resistance in newtons (orpounds-force). The method is not applicable for film orsheeting material where brittle failures occur during testing orwhere maximum extension is greater than 101.6 mm (4 in.).NOTE 1Film has been arbitrarily defined as sh

5、eeting having nominalthickness not greater than 0.25 mm (0.010 in.).1.2 Constant-Rate-of-Grip Separation TestThis testmethod employs a constant rate of separation of the gripsholding the test specimen.1.2.1 Specimen extension may be measured in this testmethod by grip separation.1.3 The values state

6、d in SI units are to be regarded as thestandard. The values given in parentheses are provided forinformation only.1.4 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 s

7、afety and health practices and determine the applica-bility of regulatory limitations prior to use.NOTE 2There is no similar or equivalent ISO standard.2. Referenced Documents2.1 ASTM Standards:3D 618 Practice for Conditioning Plastics for TestingD 882 Test Method for Tensile Properties of Thin Plas

8、ticSheetingD 883 Terminology Relating to PlasticsD 4000 Classification System for Specifying Plastic Mate-rialsD 5947 Test Methods for Physical Dimensions of SolidPlastics SpecimensE4 Practices for Force Verification of Testing MachinesE 691 Practice for Conducting an Interlaboratory Study toDetermi

9、ne the Precision of a Test Method2.2 ASTM Adjuncts:Die Drawings43. Terminology3.1 Definitions:Definitions of terms applying to this test method appear inTerminology D 883.4. Summary of Test Method4.1 The force to initiate tearing across a specific geometryof a film or sheeting specimen is measured u

10、sing a constant-rate-of-grip separation machine. The force necessary to initiatethe tear is calculated from the load-time or load-displacementdata.5. Significance and Use5.1 Tear resistance of plastic film or sheeting is a complexfunction of its ultimate resistance to rupture. The specimengeometry a

11、nd speed of testing in this test method are controlledto produce tearing in a small area of stress concentration atrates far below those usually encountered in service. Experi-ence has shown the test to have its best reliability for materialswhich do not have brittle failure or do not elongate great

12、er thantwo hundred percent during testing.5.2 The data from this test method furnish comparativeinformation for ranking the tearing resistance of plastic speci-mens of similar composition. Actual use performance intearing of some plastics may not necessarily correlate with datafrom this test method.

13、1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.19 on Film and Sheeting.Current edition approved Nov. 1, 2008. Published November 2008. Originallyapproved in 1949. Last previous edition approved in 2007 as D 1004 07.2T

14、he following reference may be of interest in connection with this test method:Graves, F. L., “The Evaluation of Tear Resistance in Elastomers,” India RubberWorld, Vol 111, No. 3, December 1944, pp. 305308.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer S

15、ervice at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Available from ASTM International Headquarters. Order Adjunct No.ADJD1004.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM

16、 International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.3 The resistance to tear of plastic film and sheeting, whilepartly dependent upon thickness, has no simple correlationwith specimen thickness. Hence, tearing forces measured innewtons (or pounds-for

17、ce) cannot be normalized over a widerange of specimen thickness without producing misleadingdata as to the actual tearing resistance of the material. Datafrom this test method are comparable only from specimens,which vary by no more than 610 % from the nominal oraverage thickness of all specimens te

18、sted. Therefore, thetearing resistance is expressed in maximum newtons (orpounds-force) of force to tear the specimen.5.4 The tear resistance of plastic film may be a specificationthat requires the use of this test method, but with someprocedural modifications that take precedence when adheringto th

19、e specification. Therefore, it is advisable to refer to thatmaterial specification before using this test method. Table 1 ofClassification System D 4000 lists the ASTM materials stan-dards that currently exist.6. Apparatus6.1 Testing MachineA testing machine of the constantrate-of crosshead-movement

20、 type and comprising essentiallythe following:6.1.1 Fixed MemberA fixed or essentially stationarymember carrying one grip.6.1.2 Movable MemberA movable member carrying asecond grip.6.1.3 GripsPreferably, a set of self-aligning grips forholding the test specimen between the fixed member and themovabl

21、e member of the testing machine. The grips shouldminimize both slippage and uneven stress distribution.6.1.3.1 Fixed grips are rigidly attached to the fixed andmovable members of the testing machine. Fixed grips may beused if extreme care is taken to ensure that the test specimen isinserted and clam

22、ped so that the long axis of the test specimencoincides with the direction of pull through the center line ofthe grip assembly.6.1.3.2 Self-aligning grips are attached to the fixed andmovable member of the testing machine in such a manner thatthey will move freely into alignment as soon as any load

23、isapplied so that the long axis of the test specimen will coincidewith the direction of the applied pull through the center line ofthe grip assembly.NOTE 3The specimens should be aligned as perfectly as possible withthe direction of pull so that no rotary motion that may induce slippage willoccur in

24、 the grips; there is a limit to the amount of misalignmentself-aligning grips will accommodate.NOTE 4Grips lined with thin rubber have been used successfully.Grips may be of the self-tightening type. In cases where specimensfrequently fail at the edge of the grips, the radius of curvature of the edg

25、esof the grips may be increased slightly at the point where they come incontact with the specimen.6.1.4 Drive MechanismA drive mechanism capable ofseparating the movable member (grip) from the stationarymember (grip) at a controlled velocity of 51 mm (2 in.) 65 %/min.6.1.5 Load IndicatorA suitable l

26、oad-indicating mecha-nism capable of showing the total tensile load carried by thetest specimen held by the grips. The testing machine shall beessentially free from inertial lag at the specified rate of testingand shall indicate the load with an accuracy of 61 %. Theaccuracy of the testing machine s

27、hall be verified in accordancewith Practices E4.6.1.6 Crosshead Extension IndicatorAsuitable extension-indicating mechanism capable of showing the amount ofchange in the separation of the grips (crosshead movement).6.2 ThicknessAmicrometer as prescribed in Test MethodsD 5947, or an equivalent measur

28、ing device, reading to 0.025mm (0.0001 in.) or less. The pressure exerted by the gage onthe specimen being measured shall not distort or deform thespecimen. For thin films, # 0.025 mm (0.001 in.), or filmswhich exhibit visual deformation during measurement, a maxi-mum pressure of 70 kPa (10 psi) is

29、recommended. For thickeror stiffer films, the pressure shall be between 160 and 185 kPa(23 and 27 psi).6.3 Die4A die having the dimensions shown in Fig. 1shall be used to cut all specimens. The 90 angle shall be honedsharp with no radius or have a minimum practical radius. Thecutting edge of the die

30、 shall have a 5 negative rake, and shallbe kept sharp and free from nicks to avoid leaving raggededges on the specimen. Wetting the surface of the sample andthe cutting edges of the die with water may facilitate cutting.The sample shall rest on the smooth, slightly yielding surfacethat will not dama

31、ge the die blade. Lightweight cardboard or apiece of leather belting is suitable. Care should be taken thatthe cut edges of the specimen are perpendicular to its othersurfaces and that the edges have a minimum of concavity.7. Test Specimens7.1 The test specimens shall be cut out with a die conform-i

32、ng to the dimensions shown in Fig. 1 and shall not vary bymore than 0.5 % from these dimensions. The cutting edges ofthe die shall be kept sharp and free of all nicks to avoid leavingragged edges on the specimens.NOTE 5Caution should be used to ensure all samples are the samedimension if multiple sp

33、ecimens are cut at one time by stacking (layering)film.Tolerance 6 0.5Table of Metric Equivalentsin. mm4.0 101.600.750 19.051.061 26.951.000 25.401.118 28.402.0 50.800.002 0.0510.500 12.70FIG. 1 Die for Tear Test SpecimenD10040827.2 Machine direction specimens are cut perpendicular tothe machine dir

34、ection and transverse direction specimens arecut perpendicular to the transverse direction.7.3 At least ten specimens shall be tested for each sample, inthe case of isotropic materials.7.4 Test a minimum of ten specimens each in the machinedirection and in the transverse direction for each anisotrop

35、ictest sample.7.5 Data from specimens which break at some obvious flawor which break in or at the edges of the grips shall be discardedand additional specimens tested, unless such failures constitutea variable whose effect is being studied.7.6 Data from specimens which deviate markedly from themean

36、value of all tests shall be rejected if the deviation of thedoubtful value is more than five times the standard deviationfrom the mean value obtained by excluding the doubtfulresults.NOTE 6For certain materials whose properties vary considerablythroughout the film or sheeting, as many as 50 specimen

37、s cut from randomportions of the sheet must be tested if reliable tear resistance data aredesired.8. Conditioning8.1 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 un

38、less otherwise specified by agreement or therelevant ASTM material specification. In cases of disagree-ment, the tolerances shall be 61C (61.8F) and 65%relative humidity.8.2 Test ConditionsConduct the tests at 23 6 2C (73.4 63.6F) and 50 6 10 % relative humidity unless otherwisespecified by agreemen

39、t or the relevant ASTM material speci-fication. In cases of disagreement, the tolerances shall be 61C(61.8F) and 65 % relative humidity.9. Procedure9.1 An initial jaw separation of 25.4 mm (1 in.) shall beused. The rate of travel of the power activated grip shall be51-mm (2-in.)/min.NOTE 7In this te

40、st method, resistance to tear is calculated from themaximum load recorded. In testing most plastics, this maximum load isgenerated at the onset of tearing across the 13-mm (0.5-in.) testing widthof the specimen.9.2 Measure the thickness of the specimen at several pointsin the notched area to the acc

41、uracy limits of the measuringdevices specified in 6.2. Record the average thickness inmicrons (mil).9.3 Place the specimen in the grips of the testing machine sothat the long axis of the enlarged ends of the specimen is in linewith the center line of the grip assembly.9.4 After complete rupture of t

42、he specimen, the maximumtearing load in newtons (pounds-force), and the maximumextension in mm (in.) shall be recorded.10. Calculation10.1 Calculate the mean maximum resistance to tearing, andthe maximum extension for all specimens tested in eachprincipal direction of orientation. Record maximum tea

43、r resis-tance expressed in newtons (pounds-force) to three significantfigures and maximum extension expressed in mm (in.) to twosignificant figures.NOTE 8Resistance to tear may be expressed in newtons per microns,(pounds-force per mil) of specimen thickness where correlation for theparticular materi

44、al being tested has been established. However, it shouldbe realized that comparison between films of dissimilar thickness may notbe valid.10.2 Calculate standard deviation.11. Report11.1 Report the following information:11.1.1 Complete identification of the material tested, includ-ing type, source,

45、manufacturers code number, form, principaldimensions, previous history, and orientation of sample withrespect to anisotropy, if any.11.1.2 Average thickness of each test specimen and averagethickness of all test specimens.11.1.3 Type of testing machine used.11.1.4 Number of specimens tested in each

46、principal direc-tion.11.1.5 Average value of tear resistance calculated in new-tons (pounds-force) and the maximum extension in mm (in.).11.1.6 Standard deviation from the averaged values ob-tained for specimens tested in each principal direction.12. Precision and Bias512.1 Table 1 and Table 2 are b

47、ased on a round robinconducted between 1986 and 1990 in accordance with PracticeE 691, involving seven materials tested by seven laboratories.For each material, all the samples were prepared at one source,and randomized sections of film were sent to each of thelaboratories which prepared the test sp

48、ecimens and testedthem. Each “test result” was the average of ten determinations.Each laboratory obtained two test results for each material.5Supporting data are available from ASTM Headquarters. Request RR:20-1177.TABLE 1 Initial Tear Resistance (Graves Tear) Machine DirectionMaterialValues Express

49、ed in Units of Grams-ForceAverage SrASRBrCRDLDPELD 104 314.6 31.98 55.79 89.53 156.2LLDPE 384.9 7.80 41.73 21.84 116.8Polystyrene 459.8 98.06 261.6 274.6 732.3HDPE No. 2 474.0 19.82 55.42 55.51 155.2Polypropylene 503.9 29.87 77.45 83.64 216.9HDPE No. 1 570.9 36.35 78.20 101.8 219.0Polyester 2494.0 6407.9 599.2 1142.0 1678.0ASr= within-laboratory standard deviation for the material stated. It is obtainedby pooling the standard deviations of the test results from each laboratory:Sr5 (S1!21 S2!2. 1 Sn!2#/n12BSR= between-laboratories standard devia