1、Designation: D 5342 97 (Reapproved 2002)An American National StandardStandard Test Method forResistance to Bending of Paper and Paperboard (Taber-Type Tester in Basic Configuration)1This standard is issued under the fixed designation D 5342; the number immediately following the designation indicates
2、 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. Scope1.1 This test method covers a procedure used to me
3、asure theresistance to bending of paper and paperboard.1.2 The bending moment required to deflect the free end ofa 38-mm (1.5-in.) wide vertically clamped specimen 15 fromits center line when the load is applied 50 mm (1.97 in.) awayfrom the clamp is determined. The resistance to bending iscalculate
4、d from the bending moment.1.3 Some instruments of the type described in this testmethod (see Section 6) may be equipped with ultrasensitiveattachments or may be modified to accommodate shorterspecimen lengths than that specified in this test method (seeSection 9).1.4 Test Method D 5650 describes a m
5、odification of theinstrument described in this test method for measurements inthe 0 to 10 Taber stiffness range only, and which requires asmaller test specimen. The modified procedure may be recom-mended for papers which are low in grammage or highlyflexible, or both.1.5 Test results obtained using
6、modifications of the basicTaber-type instrument such as that described in Test MethodD 5650 have been reported to be as much as 40 % differentfrom those obtained using this test method, and such modifi-cations must not be used when this test method is specified.1.6 This standard does not purport to
7、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.2. Referenced Documents2.1 ASTM Standards:D 585 Pract
8、ice for Sampling and Accepting a Single Lotof Paper, Paperboard, Fiberboard, or Related Products2D 685 Practice for Conditioning Paper and Paper Productsfor Testing2D 1968 Terminology Relating to Paper and Paper Products2D 5650 Test Method for Resistance to Bending of Paperof Low Bending Stiffness (
9、Taber-Type Tester in the 0 to 10Taber Stiffness Unit Configuration)2E 122 Practice for Calculating Sample Size to Estimate,with a Specified Tolerable Error, the Average for Charac-teristic of a Lot or Process33. Terminology3.1 DefinitionsDefinitions shall be in accordance withTerminology D 1968 and
10、the Dictionary of Paper.44. Summary of Test Method4.1 A test specimen of defined dimensions is bent through aspecified angle using a specific testing instrument. The result-ing bending moment is read from the instrument scale.4.2 The resistance to bending can be calculated from thebending moment.5.
11、Significance and Use5.1 Bending resistance of paper relates to a number ofend-use applications including wrapping, printing, copy ma-chine performance, high-speed mechanical handling of docu-ments, and other applications.6. Apparatus6.1 Description:6.1.1 The basic instrument that has been used for t
12、he testdescribed in this test method for nearly fifty years is a manuallyoperated (crank-driven) instrument. Over the years, variousimprovements in the basic instrument have been made forimproved ease of use or greater reproducibility of data, or both.These improvements include replacement of the ma
13、nual(crank) drive system with a constant speed motor, addition ofautomatic data determination, and automated instrument (mo-tor sequencing) operation. Fig. 1 shows the motor-drivenversion of the instrument (see 6.1.2). It is the motor-drivenmodel of the basic instrument that is the basis for this te
14、stmethod. However, any of the instrument variations described1This 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. Originally
15、approved in 1993. Last previous edition approved in 1995 as D 5342 95.2Annual 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 Bar
16、r Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.in this section, when properly calibrated and operated, shouldyield the same result. The components of the basic instrumentcan be seen in Fig. 1 as follows:6.1.1.1 A pendulum (A) supported in antifriction in bear-ings, carr
17、ying a vise (C) that has two clamping screws forholding and centering the test specimen, the lower edge of thevise coinciding with the center of the pendulum bearing. Thependulum is balanced, and at its lower end is a stud (D) towhich weights may be attached and that loads the pendulum ata distance
18、of 100 6 0.025 mm (3.94 in.) from its center;without added weights the loading is 10 6 0.001 g. A line (E)coinciding with the center line of the vise jaws and the weightstud (D), is engraved at the upper end of the pendulum.6.1.1.2 A vertical disk (F), driven on the same axis as thependulum by a dri
19、ving mechanism, carried two driving armattachments (G) so located as to provide the specimen with acantilevered loading length of 50 6 0.025 mm (1.97 in.) whenit is deflected 15. Fig. 1 does not show the crankdrivingmechanism. The driving arms have rollers (H) that are adjust-able to accommodate spe
20、cimens of different thicknesses. Onthe periphery of the upper part of the disk is a marked line (J)coinciding with the center line between the driving rollers (H)and the axis, and two reference lines (K and L) are engraved onthe periphery of the disk at angular distances of 7.5 and 15 onboth sides o
21、f the center mark (J).6.1.1.3 Located around the periphery of the disk (F) is afixed annular disk (M) with a load scale from 0 to 100 on bothsides of a zero point that is adjusted to coincide with the centerline mark (J), the scale indicating the bending moment requiredto flex the specimen to the ri
22、ght or to the left, the divisionsbeing in accordance with the sine of the angle through whichthe pendulum and weight are turned.6.1.1.4 Various loading weights (P) for the pendulum, togive a maximum bending moment of 5000 g-cm (490 mNm).6.1.2 For operator convenience and improved testing repro-ducib
23、ility, the “driving mechanism” (crank) of the basic unitwas replaced by a motor to drive the vertical disk (F) at aconstant rate of 210 6 20 per minute. Other than this change,the motor-driven instrument has the components of the “basicinstrument” as described in 6.1.1. The motor is reversible using
24、the switch (N), that preferably also operates an electric brake tostop the disk at any point on the scale. The motor-drivenversion of the instrument shown in Fig. 1 is the instrument inmost wide use today, and is the basis of this test method.6.1.3 More recently, automated versions of the basic inst
25、ru-ment have become available. These are two types: automaticreading of results (only), and automation of instrument opera-tion as well as reading of results.6.1.3.1 Devices are available that may be retrofitted to thebasic instrument for automatically determining and recordingthe scale readings (se
26、e section 10.2). Results are displayed ona digital readout device. In addition, the retrofitted unit mayprovide a signal output suitable for transmission to a stand-alone printer or an integrated acquisition system.6.1.3.2 Totally automated versions of the basic motor-driveninstrument (see 6.1.2), i
27、ncorporating the components describedin 6.1.2.1, and in addition automatically controlling the entiresequence of operations described in 10.2, are also available.7. Sampling7.1 Acceptance SamplingAcceptance sampling shall bedone in accordance with Practice D 585.7.2 Sampling for Other PurposesThe sa
28、mpling and thenumber of test specimens depends upon the purpose of thetesting. Practice E 122 is recommended.7.3 In sampling, take care not to bend, roll, score, orotherwise damage the area to be tested.8. Test Specimens8.1 From each test unit cut five test specimens, 38.16 0.3mm (1.506 0.01 in.) wi
29、de by 70 6 1 mm (2.75 6 0.05 in.)long, with the length parallel to the machine direction. Cutanother set of five test specimens with the length at right anglesto the machine direction. All cut specimens must be free fromscores or blemishes. A special cutter for cutting the samplesmay be available fr
30、om the vendor, or a high-precision cuttingboard may be used.9. Preparation of Apparatus9.1 Place the instrument on a firm, level surface. A standardlaboratory bench is generally quite satisfactory and should bechecked with a carpenters level to verify that it is level(front-to-back, side-to-side) wh
31、en the instrument is initiallyinstalled. Set the loading disk (F) at zero and place a chosenweight (P) on the pendulum stud. If possible, choose a weightsuch that the resulting readings for the specimen to be testedare near the center of the measured test range. Close the twojaws of the vice (C) to
32、meet on the center line of the pendulumand adjust the legs of the instrument so that the engraved mark(E) coincides with zero on the scale of M. Level the instrumentfront to back as well as side to side.9.2 Displace the pendulum 15 and release it to check thebearing friction. It should make at least
33、 20 complete swingsbefore coming to rest. If it does not, check for obviouscontamination by dust particles. In the absence of any obviousproblem, contact the vendor to arrange service or maintenance.9.3 If the instrument has a brake, check that it functionsproperly. It should “freeze” (stop and secu
34、rely hold) therotating disk (F) in place within less than a second of itsFIG. 1 Stiffness InstrumentD 5342 97 (2002)2application so that the result can be easily determined. (Opera-tion of the brake on the automated instrument is automaticallycontrolled as part of the automatic reversal from clockwi
35、se tocounterclockwise (or vice versa) rotation.)10. Calibration10.1 Calibrate the instrument and check the accuracy of theapparatus at regular intervals. The method of calibrationdepends on the type of instrument and done following themanufacturers instructions for the instrument used. Springsteel t
36、est pieces supplied by the manufacturer of the instrumentfor calibration purposes are generally used. If readings withinthe tolerance suggested by the manufacturer are not achieved,it may be necessary to return the instrument for servicing.11. Conditioning11.1 Condition the specimens and make the te
37、sts in anatmosphere in accordance with Practice D 685.12. Procedure12.1 Place a conditioned test specimen in the vise (C) withone end approximately level with its top edge and the other endbetween the rollers (H).12.2 With the two clamping screws of the vise (C) align thespecimen with the center lin
38、e of the pendulum.12.2.1 Pressure of the clamping screws may impact testresults, and clamping pressure should be firm enough to holdthe specimen, but not so firm as to compress or deform it.NOTE 1At the present time use of calibration spring steel or speci-mens of samples of known stiffness as deter
39、mined by this test method arethe only recommendations for determining if vise pressure is so great orso slight that test results are affected adversely.12.3 Turn each of the screws for adjusting the rollers (H) sothat they just contact the specimen, then after taking up thebacklash in one screw, bac
40、k off one-quarter turn to give adistance between rollers of 0.33 + 0.03 mm (0.013 + 0.001 in.)greater than the thickness of the specimen.NOTE 2On instruments not equipped with adjustable rollers (H), usethe appropriate set of rollers for the thickness of the board to be tested. Itis not necessary fo
41、r the pendulum to balance at zero with the undeflectedspecimen in place. Curvature of the specimen will result in a differencebetween the two readings which is averaged to give the stiffness of thespecimen. This difference has been used as a measure of curl, but thisshould be done with caution, as t
42、his difference may also reflect a genuinedifference in stiffness between the two orientations of the specimen withrespect to the deflecting force. If the specimen is so badly curled that bothreadings fall on the same side of zero, take the lower reading as negativewhen calculating the average. Inclu
43、de mention of this occurrence in thereport, as this much curl may make the material useless for its intendedpurpose.12.4 For the Basic Motor-Driven InstrumentSwitch onthe motor to rotate the loading disk (F) to the left and thusdeflect the specimen until the engraved mark (E) on thependulum is align
44、ed with the 15 mark (L) on the loading disk.Stop the motor, record the scale reading on the fixed annulardisk (M), and immediately return the loading disk to zero (seeNote 2). Take a similar reading by deflecting the specimen tothe right. The stiffness of the specimen is taken as the averageof the t
45、wo readings multiplied by the factor required for theinstrument range weight used (see the manufacturers instruc-tions). Test five specimens cut in each direction.NOTE 3When the motor is “stopped,” an electric brake immediatelystops the disk and holds it in place so a reading can be taken. Oninstrum
46、ents not equipped with an electric brake, take the reading as thedisk rotates over the end point.12.5 For the basic motor-driven instrument retrofitted withdigital readout, the scale readings are automatically “captured”and are recorded from a digital display. The motor is started,stopped, and rever
47、sed in accordance with 12.4.12.6 For the Automated InstrumentThe operations de-scribed in 12.4 are automatically done in sequence after the testis initiated. Scale readings (left and right) are displayed on theinstrument readout.12.7 If the specimen is very stiff, or if it creases or checkswhen flex
48、ed as much as 15, use the 7.5 deflection mark(manual instrument) or 7.5 deflection setting (automatedinstrument). Multiply the results by 2.0 for an approximatecomparison with the 15 deflection. If a 7.5 deflection is soused, state this clearly in the report.13. Calculation13.1 Bending MomentCalcula
49、te the bending moment asthe average of the two readings (left and right deflection)multiplied by the factor required for the chosen weight, P, thatwas used during the test (see the manufacturers instructions).13.2 Where SI results are desired, convert the value instiffness to millinewton metres by multiplying by 0.098066.13.3 Resistance to BendingDivide the bending moment(mNm) by the length (m). Result is force (mN) required todeflect the sample through the specified distance (Length(m) = 0.050 m).14. Report14.1 Report the following information:14.1.1 Bendin
