ASTM D2923-2008 Standard Test Method for Rigidity of Polyolefin Film and Sheeting《聚烯烃薄膜及薄板硬度的标准试验方法》.pdf

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1、Designation: D 2923 08Standard Test Method forRigidity of Polyolefin Film and Sheeting1This standard is issued under the fixed designation D 2923; 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 describes two procedures for measur-ing the rigidity of polyolefin film and sheeting.1.2 Procedure A prescribes a procedure

3、using high-voltagestatic eliminators and the use of TFE-fluorocarbon2-coatedplates to overcome the spurious effects of static electricity andfriction.1.3 Procedure B prescribes the use of a fine powder onuncoated plates to achieve a similar effect.NOTE 1Although the two procedures are designed to ac

4、hieve similareffect, they may not achieve the same results.1.4 The values stated in SI units are to be regarded asstandard. The values given in parentheses are for informationonly.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is therespo

5、nsibility 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.NOTE 2There is no known ISO equivalent to this standard.2. Referenced Documents2.1 ASTM Standards:3D 618 Practice for Conditioning Plas

6、tics for TestingD 1898 Practice for Sampling of Plastics43. Terminology3.1 Definitions:3.1.1 rigiditythat combination of thickness and inherentstiffness of a polyolefin film or sheet which resists flexure.4. Summary of Test Method4.1 The resistance to flexure of the sample is measured by astrain gau

7、ge affixed to the end of a beam, the opposite end ofwhich flexes the sample by forcing it into a groove or slot in ahorizontal platform upon which the sample rests.An indicatingmicroammeter, wired to the strain gauge, is calibrated in gramsof load sensed by the strain gauge. The rigidity is read dir

8、ectlyfrom the meter and expressed as grams per centimetre ofsample width.5. Significance and Use5.1 The rigidity of a polyolefin web can affect its machin-ability, particularly on those packaging machines where a cutportion of a web is required to remain flat momentarily withoutbeing supported on al

9、l sides.5.2 Rigidity is not a simple property since it depends on twoother properties of the sample: the thickness (gauge), and thestiffness which is an inherent property of the material of whichthe film or sheet is made. The combined effect of these twofactors is the rigidity that influences perfor

10、mance on convertingmachines.6. Interferences6.1 Static electricity has considerable influence on themeasured rigidity. It contributes to poor precision and accu-racy, frequently giving results biased toward the high side.6.2 To a lesser extent, precision and accuracy are adverselyaffected by the fri

11、ctional properties of the sample, particularlywhen the coefficient of friction is close to 1.6.3 The interference caused by the level of static electricityand friction of the specimen is overcome in Procedure A byelectrically destaticizing the sample and using TFE-fluorocarbon-coated plates and in P

12、rocedure B by dusting theplatform with a fine powder at the start of the test.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. Orig

13、inallyapproved in 1970. Last previous edition approved in 2006 as D 2923 - 06.2This test method is based on the use of Teflon, a registered trademark of E. I.duPont de Nemours polyolefins; rigidity; sheetAPPENDIX(Nonmandatory Information)X1. CALIBRATIONX1.1 The instrument must be located on a solid,

14、 vibration-free, level surface. Refer to Fig. X1.1 for the placement andnames of the components of the Handle-O-Meter.X1.2 The opening through which the penetrator beamtravels must be checked each time the instrument is used oronce a week if the machine is in continual use. For routinework, a 5-mm (

15、0.197-in.) opening will be used.X1.2.1 Place the centering gauge shown in Fig. X1.2 in theopening with the penetrator beam resting in the upper slot ofthe centering gauge. Fig. X1.3X1.2.2 The gauge should fit snugly in the opening (no morethan 0.025-mm (0.01-in.) clearance on each side).FIG. X1.1 Ha

16、ndle-O-Meter ComponentsFIG. X1.2 Centering GaugeD2923083X1.2.3 Adjust the opening if the gauge is loose by releasingthe set screws holding the plate and sliding both sides untilcontact is made with the centering gauge. Tighten the setscrews holding the plates and remove the gauge.X1.3 The following

17、steps should be followed in consecu-tive order to check the calibration of the Handle-O-Meter.Refer to Fig. X1.1 for placement of control.X1.3.1 Put toggle switch in RUN position and press themomentary contact switch. The blade of the penetration beamwill move into the slot to a depth governed by th

18、e position ofthe load cell anchor nut.X1.3.2 Adjust the load cell anchor nut so that the blade willpenetrate to a depth of 7.94 mm (0.3125 in.) below the surfaceof the platform. Turning off the nut clockwise will increase thedepth setting and vice versa.X1.3.3 With the toggle switch in the OFF posit

19、ion, adjustthe microammeter to the mechanical zero with the zero adjustscrew on the front of the microammeter.X1.3.4 With the toggle switch in either the RUN or OFFposition, the microammeter should read zero. Adjust thepenetration beam counterweight until a zero reading occurs.X1.3.5 Place the toggl

20、e switch in the RUN position andpress the momentary contact switch until the cycle starts.When the blade reaches the level of the specimen platform,change the toggle switch to the TEST position. The microam-meter should continue to read zero. This was a test to determineif the microammeter reads zer

21、o when the blade first touches thespecimen.X1.3.6 Reach through the side door on the right side of thecase and hang the range calibrating weight in the groove of thecounterweight stand.X1.3.7 With the weight in this position, the reading on themicroammeter should be 40.0 g. If it is not correct, rea

22、chthrough the side door and adjust the range rheostat until thereading is 40.0 g.NOTE X1.1Handle-O-Meter of a capacity double that of No. 211-2 isavailable. This is accomplished by furnishing an electric load cell ofhigher capacity, a switch shunted across a meter fora2to1ratio ofindications. There

23、is a HI-LO switch on the face of the instrument andwith the LO position the instrument operates the same as No. 211-2 andreadings are taken directly from the meter; however, with the switch in theHI position, all meter readings must be doubled to reflect the shuntingoffset and therefore can be used

24、for stiffer or higher capacity tests.X1.3.8 Remove the calibrating weight and check that thezero reading is indicated on the microammeter. If the readinghas shifted, repeat X1.3.5 to and including X1.3.7.X1.3.9 Place the 40-g augmenting weight on the blade,while the 40.0-g range calibrating weight i

25、s hung on thecounterweight stud. The microammeter reading should now bezero, since each weight is counteracting the other.X1.3.10 Remove both weights before going on to theoperating procedures.X1.3.11 The actual weight of the calibration weight and theaugmenting weight must be checked once a month a

26、nd weigh40 6 0.1 g.SUMMARY OF CHANGESCommittee D20 has identified the location of selected changes to this standard since the last issue(D 2923 - 06) that may impact the use of this standard. (November 1, 2008)(1) Revised Section 9.ASTM International takes no position respecting the validity of any

27、patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revis

28、ion at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your c

29、omments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrig

30、hted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).FIG. X1.3 Specimen in Place for TestD2923084