1、Designation:D217616(Reapproved 2021)Standard Test Method forFolding Endurance of Paper and Plastics Film by the M.I.T.Tester1This standard is issued under the fixed designation D2176;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,th
2、e 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.Scope1.1 This test method describes t
3、he use of the M.I.T.-typefolding apparatus for determining folding endurance of paperand plastics film.The M.I.T.tester can be adjusted for samplesof any thickness;however,if the outer layers thicker than about0.25 mm(0.01 in.)rupture during the first few folds,the testloses its significance.The pro
4、cedure for the Schopper-typeapparatus is given in Test Method D643.1.2 The values stated in SI units are to be regarded asstandard.The values given in parentheses are mathematicalconversions to inch-pound units that are provided for informa-tion only and are not considered standard1.3 This standard
5、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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international
6、 standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.
7、Referenced Documents2.1 ASTM Standards:2D585 Practice for Sampling and Accepting a Single Lot ofPaper,Paperboard,Fiberboard,and Related Product(Withdrawn 2010)3D643 Test Method for Folding Endurance of Paper by theSchopper Tester(Withdrawn 2010)3D685 Practice for Conditioning Paper and Paper Product
8、sfor TestingD1968 Terminology Relating to Paper and Paper ProductsE122 Practice for Calculating Sample Size to Estimate,WithSpecified Precision,the Average for a Characteristic of aLot or Process3.Terminology3.1 Definitions shall be in accordance with TerminologyD1968 and the Dictionary of Paper.44.
9、Significance and Use4.1 The folding endurance is frequently used to estimate theability of the paper and plastics film to withstand repeatedbending,folding,and creasing.4.2 Folding endurance has also been found useful in mea-suring the deterioration of paper and plastics film upon aging.5.Apparatus5
10、.1 Folding Tester,consisting of:5.1.1 A spring-loaded clamping jaw constrained to movewithout rotation in a direction perpendicular to the axis ofrotation of the folding head specified below and having itsclamping surfaces in the plane of this axis.The load is appliedby a spring attached to the jaw
11、assembly which is easilyadjustable to provide any desired tension on the specimenwithin range of 4.9 to 14.72 N(500 to 1500 gf).The deflectionof the spring when loaded shall be at least 17 mm(0.67in.)/9.81 N,which is achieved by using a weight of 1 kg mass.5.1.2 An oscillating folding head supportin
12、g two smooth,cylindrical folding surfaces parallel to,and symmetricallyplaced with respect to,the axis of rotation.Each of the twofolding surfaces shall have a radius of curvature of 0.38 mm(0.015 6 0.001 in.)and a width of 19 mm(0.75 6 0.04 in).The distance separating the folding surfaces is greate
13、r than the1This classification system is under the jurisdiction ofASTM Committee D20 onPlastics and is the direct responsibility of Subcommittee D20.15 on ThermoplasticMaterials.Current edition approved July 1,2021.Published July 2021.Originally approvedin 1956.Last previous edition approved in 2016
14、 as D2176-16.DOI:10.1520/D2176-16R21.2For 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.3The last approved version of
15、 this historical standard is referenced onwww.astm.org.4Available from Technological Association of the Pulp and Paper Industry(TAPPI),15 Technology Parkway South,Suite 115,Peachtree Corners,GA 30092,http:/www.tappi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken
16、,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1uncompressed thickness of the specimen being tested by nomore than 0.25 mm(0.010 in.).The position of the axis ofrotation is midway between the common tangen