ASTM_D_2923_-_13.pdf

Designation:D292313StandardTest Method forRigidity of Polyolefin Film and Sheeting1This standard is issued under the fixed designation D2923;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()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 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 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 known ISO equivalent to this standard.2.Referenced Documents2.1 ASTM Standards:3D618 Practice for Conditioning Plastics for Testing3.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 gauge 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 directlyfrom the meter and expressed as grams per centimetre ofsample width.5.Significance and Use5.1 The rigidity of a polyolefin web can affect itsmachinability,particularly on those packaging machines wherea cut portion of a web is required to remain flat momentarilywithout being supported on all sides.5.2 Rigidity is not a simple property since it depends onother properties of the specimen:the thickness(gauge),orien-tation effects,and the stiffness which is an inherent property ofthe material of which the film or sheet is made.The combinedeffect of these factors is the rigidity that influences perfor-mance on converting machines.6.Interferences6.1 Static electricity has considerable influence on themeasured rigidity and contributes to poor precision andaccuracy,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:1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.19 on Film,Sheeting,andMolded Products.Current edition approved Sept.1,2013.Published September 2013.Originallyapproved in 1970.Last previous edition approved in 2008 as D2923-08.DOI:10.1520/D2923-13.2This test method is based on the use of Teflon,a registered trademark of E.I.duPont de Nemours&Co.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.*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 StatesNOTICE:This standard has either been superseded and replaced by a new version or withdrawn.Contact ASTM International(www.astm.org)for the latest information17.1.1 Handle-O-Meter,orequivalent,withTFE-fluorocarbon-coated plates complete with calibrating and aug-menting weights.47.1.2 Cutting Board or Template suitable for preparing 203by 203-mm(8.0 by 8.0-in.)specimens.7.1.3 High-Voltage Static Eliminator5and Generator.7.2 Procedure B: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 Samples shall be randomly taken from roll or sheetstock manufactured by a process in st