1、Designation:D 2176 97a(Reapproved 2002)An American National StandardStandard Test Method forFolding Endurance of Paper by the M.I.T.Tester1This standard is issued under the fixed designation D 2176;the number immediately following the designation indicates the year oforiginal adoption or,in the case
2、 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.Scope1.1 This test method describes the use of the M.I.T.-typefolding apparatus for determining folding en
3、durance of paper.The M.I.T.tester can be adjusted for papers of any thickness;however,if the outer fibrous layers of paper thicker than about0.25 mm(0.01 in.)rupture during the first few folds,the testloses its significance.The procedure for the Schopper-typeapparatus is given in Test Method D 643.T
4、his test method isthe technical equivalent of TAPPI T 511.1.2 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
5、 of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:D 585 Practice for Sampling and Accepting a Single Lot ofPaper,Paperboard,Fiberboard,and Related Products2D 643 Test Method for Folding Endurance of Paper by theSchopper Tester2D 685 Practice for Conditioning Paper and
6、Paper Productsfor Testing2D 1968 Terminology Relating to Paper and Paper Products2E 122 Practice for Calculating Sample Size to Estimate,with a Specified Tolerable Error,the Average for a Char-acteristic of a Lot or Process33.Terminology3.1 Definitions shall be in accordance with Terminology D1968 a
7、nd the Dictionary of Paper.44.Significance and Use4.1 The folding endurance of a paper is frequently used toestimate the ability of the paper to withstand repeated bending,folding,and creasing,and may be encountered as a measure ofthe quality of bank note paper,or document paper.4.2 Folding enduranc
8、e has also been found useful in mea-suring the deterioration of paper upon aging.5.Apparatus5.1 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 itscl
9、amping surfaces in the plane of this axis.The load is appliedby a spring attached to the jaw 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(0.67 in.)/9.81
10、N,which is achieved by using a weight of 1 kg mass.5.1.2 An oscillating folding head supporting 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 i
11、n.)and a width of 19 mm(0.75 in.6 0.04 in).The distance separating the folding surfaces is greater than theuncompressed thickness of the paper being tested by no morethan 0.25 mm(0.010 in.).The position of the axis of rotationis midway between the common tangent planes of the twofolding surfaces.The
12、 folding head is provided with a clampingjaw with its nearest edge not less than 9.5 mm(0.375 in.)beyond the axis of rotation.The rotary oscillating movement ofthe head is such as to fold the paper through an angle of 1356 2,both to the right and to the left of the position of theunfolded specimen.5
13、.1.3 Various size folding heads are required for testingdifferent thicknesses of paper.Heads available will accommo-date thicknesses from 0 to 0.25 mm(0 to 0.01 in.),0.25 to 0.50mm(0.01 to 0.02 in.),0.50 to 0.75 mm(0.02 to 0.03 in.),0.75to 1.02 mm(0.03 to 0.04 in.),and 1.02 to 1.25 mm(0.04 to0.05 in
14、.).5.2 Power Driven Device,for imparting a rotary oscillatingmotion of 175 6 25 cycles/min to the folding clamp.5.3 Counter,for registering the number of double foldsrequired to break the specimen and a device to stop theinstrument when the specimen breaks.5.4 Strip Cutter,to cut 15-mm wide parallel
15、 strips within60.02 mm with clean edges.1This test method is under the jurisdiction of ASTM Committee D06 on Paperand Paper Products and is the direct responsibility of Subcommittee D06.92 on TestMethods.Current edition approved Dec.10,1997.Published November 1998.Originallypublished as D 2176 63 T.
16、Last previous edition D 2176 97.2Annual Book of ASTM Standards,Vol 15.09.3Annual Book of ASTM Standards,Vol 14.02.4Available from the Technical Association of the Pulp and Paper Industry,P.O.Box 105113,Atlanta,GA 30348.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.5.5 A means for controlling the temperature of the foldinghead so that,during folding,it does not increase more than0.5C.Temperature rises of this magnitude will reduce th
