ASTM_D_2923_-_01.pdf

Designation:D 2923 01Standard 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 in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)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 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.NOTE1Although the two procedures are designed to achieve similareffect,they may not achieve the same results.1.4 The values stated in SI units are to be regarded as thestandard.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 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.NOTE2There is no similar or equivalent ISO standard.2.Referenced Documents2.1 ASTM Standards:D 618 Practice for Conditioning Plastics for Testing3D 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 gage 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 gage,is calibrated in gramsof load sensed by the strain gage.The rigidity is read directlyfrom 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 all sides.5.2 Rigidity is not a simple property since it depends on twoother properties of the sample:the thickness(gage),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 performance 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 frictional 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 Procedure B by dusting theplatform with a fine powder at the start of the test.7.Apparatus7.1 Procedure A:7.1.1 Handle-O-Meter,orequivalent,withTFE-fluorocarbon-coated plates complete with calibrating and aug-menting weights.57.1.2 Cutting Board or Template suitable for preparing 203by 203-mm(8.0 by 8.0-in.)specimens.7.1.3 High-Voltage Static Eliminator6and Generator.7.2 Procedure B:1This test method is under the jurisdiction ofASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.19 on Film and Sheeting.Current edition approved August 10,2001.Published October 2001.Originallypublished as D 2923 70.Last previous edition D 2923 95.2This test method is based on the use of Teflont,a registered trademark of E.I.duPont de Nemours&Co.3Annual Book of ASTM Standards,Vol 08.01.4Discontinued;see 1997 Annual Book of ASTM Standards,Vol 08.01.5The Handle-O-Meter and auxiliary equipment are available from Thwing-Albert Instrument Co.,Philadelphia,PA.6Simco Shockless Bars are suitable for this test method.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.7.2.1 Handle-O-Meter,or equivalent,complete with cali-brating and augmenting weights.7.2.2 Cutting Board or Template suitable for preparing 203by 203-mm(8.0 by 8.0-in.)specimens.7.2.3 Fine-Particle Silica,starch,or equivalent,having anapproximate nominal particle size of 50 m or less.8.Sampling8.1 The material shall be sampled in accordance withPractice D 1898.9.Test Specimens9.1 Using a cutting board or template,cut a minimum ofthree 203 by 203-mm(8.0 by 8.0-in.)test specimens with theedges parallel to the machine and t