1、Designation: D1709 15D1709 15aStandard Test Methods forImpact Resistance of Plastic Film by the Free-Falling DartMethod1This standard is issued under the fixed designation D1709; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、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 These test methods cove
3、r the determination of the energy that causes plastic film to fail under specified conditions of impactof a free-falling dart. This energy is expressed in terms of the weight (mass) of the missile falling from a specified height whichwould result in 50 % failure of specimens tested.1.2 Two test meth
4、ods are described:1.2.1 Test Method A employs a dart with a 38.10 6 0.13-mm (1.500 6 0.005-in.) diameter hemispherical head dropped froma height of 0.66 6 0.01 m (26.0 6 0.4 in.). This test method maycan be used for films whose impact resistances require massesof about 50 g or less to about 26 kg to
5、 fracture them.1.2.2 Test Method B employs a dart with a 50.80 6 0.13-mm (2.000 6 0.005-in.) diameter hemispherical head dropped froma height of 1.50 6 0.031.52 6 0.03 m (60.0 + 0.25, 1.70 in.). Its range of applicability is from about 0.3 kg to about 26 kg.1.3 Two testing techniques are described:1
6、.3.1 The standard technique is the staircase method. By this technique, a uniform the missile weight increment is employedduring test and the missile weight the test is decreased or increased by the uniform incrementincrements after test the testing ofeach specimen, depending upon the result (fail o
7、r not fail) observed for the specimen.1.3.2 The alternative technique provides for testing specimens in successive groups of ten. One missile weight is employed foreach group and the missile weight is varied in uniform increments from group to group.1.3.3 The staircase technique and the alternative
8、technique give equivalent results both as to the values of impact failure weightwhich are obtained and as to the precisions with which they are determined.1.4 The values stated in SI units are to be regarded as standard. The values stated in parentheses are for information only.NOTE 1Tests on materi
9、als that do not break, for any reason, are not considered to be valid. It has been noted that certain materials may stretch sofar as to bottom out at the base of certain test instruments without actually rupturing. Subcommittee D20.19 is currently considering methods for testingthese materials. Anyo
10、ne interested in participating in a Task Group should contact the Chairman of Subcommittee D20.19 through ASTM InternationalHeadquarters.1.5 This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of theuser of this standard to establi
11、sh appropriate safety and health practices and determine the applicability of regulatory limitationsprior to use.NOTE 2Film has been arbitrarily defined as sheeting having nominal thickness not greater than 0.25 mm (0.010 in.).NOTE 3This test method is technically equivalent to ISO 7765-1: 1988, wit
12、h the exception of a larger tolerance on the drop height in Test MethodB, smaller tolerances on the dart diameters for Test Methods A and B, and the requirement for a vented dart well in 5.1.1. Also, the ISO method doesnot allow the alternative testing technique described in Section 11 of this test
13、method.2. Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD883 Terminology Relating to Plastics1 These test methods are under the jurisdiction of ASTM Committee D20 on Plastics and are the direct responsibility of Subcommittee D20.19 on Film, Sheeting, andM
14、olded Products.Current edition approved Jan. 1, 2015May 15, 2015. Published January 2015June 2015. Originally approved in 1959. Last previous edition approved in 20092015 asD1709 09.D1709 15. DOI: 10.1520/D1709-15.10.1520/D1709-15A.2 For referencedASTM standards, visit theASTM website, www.astm.org,
15、 or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes
16、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 official
17、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 States1D1248 Specification for Polyethylene Plastics Extrusion Materials for Wire and CableD3420 Test Method for Pendul
18、um Impact Resistance of Plastic FilmD4272 Test Method for Total Energy Impact of Plastic Films By Dart DropD6988 Guide for Determination of Thickness of Plastic Film Test SpecimensE177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE691 Practice for Conducting an Interlaborator
19、y Study to Determine the Precision of a Test Method2.2 ISO Standard:ISO 7765:1988 Plastic Film and SheetingDetermination of Impact Resistance by the Free Falling Dart MethodPart 1:Staircase Method33. Terminology3.1 DefinitionsFor definitions related to plastics, see Terminology D883.3.2 Definitions
20、of Terms Specific to This Standard:3.2.1 failureany break through the film that can be observed readily by feeling or by viewing the specimen under backlightedcondition.3.2.2 impact failure weightthat missile weight, estimated statistically, at which 50 % of the specimens would fail in thespecified
21、test.3.2.3 missile weightthe weight (mass) of the dart plus the total value of incremental weights attached plus the locking collar.4. Significance and Use4.1 Test Methods A and B are used to establish the weight of the dart when 50 % of the specimens fail under the conditionsspecified. Data obtaine
22、d by one test method cannot be compared directly with the other test method nor with those obtained fromtests employing different conditions of missile velocity, impinging surface diameter, effective specimen diameter, and materialconstruction and finish of the dart head, and film thickness. The val
23、ues obtained by these test variables are highly dependent onthe method of film fabrication.4.2 The results obtained by Test MethodsAand B are greatly influenced by the quality of film under test. The confidence limitsof data obtained by this procedure can, therefore, vary significantly, depending on
24、 the sample quality, uniformity of film gage, diemarks, contaminants, etc. (see Section 15).4.3 Test Methods A and B have been found useful for specification purposes. Correlation between test results and fieldperformance can usually be established.NOTE 4With sufficient data, correlation between tes
25、t results and field performance can usually be established.4.4 The impact resistance of plastic film, while partly dependent on thickness, has no simple correlation with sample thickness.Hence, impact values cannot be normalized over a range of thickness without producing misleading data as to the a
26、ctual impactresistance of the material. Data from these test methods are comparable only for specimens that vary by no more than 625 % fromthe nominal or average thickness of the specimens tested.4.5 Several impact test methods are used for film. It is sometimes desirable to know the relationships a
27、mong test results derivedby different test methods.Astudy was conducted in which four films made from two resins (polypropylene and linear low-densitypolyethylene), with two film thicknesses for each resin, were impacted using Test Methods D1709 (MethodA), D3420 (ProceduresA and B), and D4272. The t
28、est results are shown in the Appendix. Differences in results between Test Methods D1709 and D4272may be expectedare not unusual since Test Methods D1709 represents failure initiated energy, while Test Method D4272 isinitiation plus completion energy. Some films may show exhibit consistency when the
29、 initiation energy is the same as the totalenergy. This statement and the test data also appear in the significance sections and appendixes of Test Methods D3420 and D4272.5. Apparatus5.1 The apparatus shall be constructed essentially as shown in Fig. 1, using the following components common to both
30、 testmethods:5.1.1 Dart WellIf the dart impact machine utilizes an enclosed dart well, it must contain a single unobstructed vent with aminimum area of 625 mm2 (1 in.2) to provide adequate venting.NOTE 5Some dart impact machine designs utilize enclosed dart wells that do not permit adequate venting
31、to the atmosphere during impact. Data haveshown that this has a significant effect on the observed impact value, especially with films that exhibit high elongation during testing, resulting inatypically high impact values.NOTE 6The use of smaller, multiple vents is permitted if it can be demonstrate
32、d that the venting efficiency is comparable and has no statisticallysignificant effect on the values obtained.3 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.D1709 15a25.1.2 Specimen ClampAtwo-piece annular specimen cla
33、mp having an inside diameter of 125 6 2.0127 6 2.0 mm (5.0 + 0.0,0.15 in.) and conforming to the following requirements:5.1.2.1 The lower or stationary half of the clamp shall be mounted rigidly so that the plane of the specimen is horizontal.5.1.2.2 The upper or movable part of the clamp shall be d
34、esigned to maintain positive and plane contact with the lower part ofthe clamp when in position. The clamps shall be provided with suitable means of maintaining sufficient contact to hold the filmsample firmly in place during the test. Pneumatically operated clamps have been successfully employed.5.
35、1.2.3 Rubber-like gaskets maycan be affixed to the specimen contact surfaces of both clamps to provide a cushion whichminimizes thickness variation effects. Rubber gasketing 3.0 6 1 3.18 6 1 mm (0.125 + 0.025, 0.04 in.) thick, of 50 to 60 ShoreA durometer hardness, 125 6 2.0127 6 2.0 mm (5.00 + 0.00
36、, 0.15 in.) in inside diameter and 150 6 3.0152 6 3.0 mm(6.0 + 0.02, 0.2 in.) in outside diameter has been found satisfactory for this purpose.5.1.2.4 Slippage To minimize or eliminate slippage of films greater than 0.10 mm (0.004 in.) in thickness may be minimizedor eliminated by securing thickness
37、, crocus cloth or 50D garnet abrasive paper can be secured to the gaskets with double sensitivedouble-sided tape so that the abrasive surface is in direct contact with the film. There should The clamping force shall be sufficientclamping force to eliminate any detectable slippage. Other means of red
38、ucing slippage such as additional clamping devices orpositive clamping surfaces may be usedare also acceptable provided that the film is not weakened at the inside wall of the specimenclamps and that the effective diameter of 125 6 2.0127 6 2.0 mm (5.00 + 0.00, 0.15 in.) of the film is not changed.N
39、OTE 1Values for tolerances in SI units are to be regarded as standard. The numbers in parentheses reflect the allowable tolerance range of olderequipment and are only provided for information and, in many cases, do not correspond directly to the tolerances in SI units. The differences are notexpecte
40、d to have a significant effect on the results but the dimensions in SI units shall be used in cases of dispute.NOTE 2Legend Dart Assembly:A. Steel shaft tip 6.5 6 1 mm (0.25 + 0.04, 0.03 in.) OD by 12.5 6 0.2 mm (0.50 + 0.00, 0.02 in.) long.B. Dart shaft: 6.5 6 1 mm (0.25 + 0.04, 0.03 in.) OD and at
41、 least 115 mm (4.5 in.) long: 14 20 thd. (N.C.) 12.5 6 0.2 mm (0.50 + 0.00, 0.02 in.)long on bottom: No. 540 thd. (N.F.) for steel tip.C. Hemispherical head: MethodA38.10 6 0.13mm (1.500 6 0.005in.) in diameter. Method B50.80 6 0.13mm (2.000 6 0.005 in.) in diameter.D. Removable weights.E. Collar an
42、d screw.FIG. 1 Apparatus for Free-Falling Dart Impact Test for Plastic FilmD1709 15a35.1.3 Dart Release Mechanism, capable of supporting a 2-kg weight the heaviest weight utilized for testing (up to 6 kg) shallbe used for supporting and releasing the dart assembly. It shall be equipped with a center
43、ing device, such as a removable plumbbob, to ensure a reproducible drop. Either an electromagnetic- or pneumatic-operated release mechanism may be used. isacceptable.5.1.4 Positioning DeviceThe apparatus shall be able to drop the dart from heights of 0.66 6 0.01 m (26.0 6 0.4 in.) for TestMethod A a
44、nd 1.50 6 0.031.52 6 0.03 m (60.0 + 0.25, 1.70 in.) for Test Method B. The distance between the impinging surfaceof the dart head and the surface of the test specimen is considered to be the drop height. The dart shall be positioned verticallyabove the center of the test specimen.5.1.5 Micrometer, o
45、r other suitable thickness gauge, for measuring specimen thickness in accordance with Guide D6988.5.1.6 Cushioning and Shielding Devices, to protect personnel and to avoid damaging the impinging surface of the dart. Thesedevices shall not interfere with the dart or the specimen prior to penetrating
46、the specimen.5.1.7 Collar with inside diameter of approximately 7 mm (0.28 in.) and with set screw for securing collar to dart shaft.5.2 Darts for Test Methods A and B shall have hemispherical heads, each fitted with a 6.5 6 1-mm6.4 6 1-mm (0.25 + 0.04,0.03-in.) diameter shaft at least 115114.3 mm (
47、4.5 in.) long to accommodate removable incremental weights. Each dart weightshall be known to 60.5 % relative. Dart head surfaces shall be free of nicks, scratches, or other irregularities. The shaft shall beattached to the center of the flat surface of the head with its longitudinal axis perpendicu
48、lar to the surface. If an electromagnet isused, the shaft shall be made of material that is not magnetic and shall have a steel tip 12.5 6 0.212.7 6 0.2 mm (0.50 + 0.00,0.02 in.) long at the end held by the electromagnet.5.2.1 For Test Method A, the dart head shall be 38.10 6 0.13mm (1.500 6 0.005in
49、.) in diameter. It may be constructedofAcceptable materials of construction include smooth, polished aluminum, phenolic, or other low-density material of similarhardness. hardness and durability.5.2.2 For Test Method B, the dart head shall be 50.80 6 0.13mm (2.000 6 0.005 in.) in diameter. It may be constructedofAcceptable materials of construction include smooth, polished stainless steelaluminum, phenolic, or other low-density materialof similar durability. hardness and durability.5.2.3 The material of construction of the dart head s
