1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 2493-2:2011Paper and board Determination of bendingresistancePart 2: Taber-type testerBS ISO 2493-2:2011 BRITISH STANDARDNational forewordThis British Standard is the UK i
2、mplementation of ISO 2493-2:2011. Together with BS ISO 2493-1:2010, it supersedes BS 3748:1992 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee PAI/11, Methods of test for paper, board and pulps.A list of organizations represented on this committee can
3、be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. BSI 2011 ISBN 978 0 580 66120 4 ICS 85.060 Compliance with a British Standard cannot confer immunity from legal obligati
4、ons.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2011.Amendments issued since publicationDate T e x t a f f e c t e dBS ISO 2493-2:2011Paper and board Determination of bending resistance Part 2:Taber-type testerPapier et carton
5、 Dtermination de la rsistance la flexion Partie 2: Rigidimtre Taber ISO 2011Reference numberISO 2493-2:2011(E)First edition2011-11-15ISO2493-2INTERNATIONAL STANDARDBS ISO 2493-2:2011ISO 2493-2:2011(E)COPYRIGHT PROTECTED DOCUMENT ISO 2011All rights reserved. Unless otherwise specified, no part of thi
6、s publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211
7、Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in Switzerlandii ISO 2011 All rights reservedBS ISO 2493-2:2011ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodie
8、s). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and n
9、on-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Par
10、t 2.The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting
11、a vote.Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 2493-2 was prepared by Technical Committee ISO/TC 6, Paper, board and pulps, Subcommittee S
12、C 2, Test methods and quality specifications for paper and board.This first edition, together with ISO 2493-1, cancels and replaces ISO 2493:1992, which has been technically revised. In the revision, ISO 2493:1992 was divided into two parts due to different measuring principles. ISO 2493-1 describes
13、 the constant rate of deflexion and this part of ISO 2493 describes the Taber-type tester. ISO 2493-1 also gives the possibility to use a smaller bending length and a lower bending angle if needed. Optional calculation in index form has been added. A precision statement has been added in informative
14、 Annex A. ISO 2493 consists of the following parts, under the general title Paper and board Determination of bending resistance: Part 1: Constant rate of deflection Part 2: Taber-type testerISO 2493-2:2011(E) ISO 2011 All rights reserved iiiBS ISO 2493-2:2011IntroductionIn ISO 2493:1992, two princip
15、les for determining the bending resistance were incorporated in the same standard although the two principles are very different.One principle involved the deflection of an equal number of test pieces with opposing surfaces towards the direction of deflection; this principle is described in ISO 2493
16、-1.The other principle used a Taber-type tester, where the test piece is inserted and deflected to the top side and then, without changing the test piece, it is deflected in the opposite direction. This principle is described in this part of ISO 2493. The method is based on TAPPI Test Method T 489 o
17、m-084.ISO 2493-2:2011(E)iv ISO 2011 All rights reservedBS ISO 2493-2:2011INTERNATIONAL STANDARD ISO 2493-2:2011(E)Paper and board Determination of bending resistance Part 2:Taber-type tester1 ScopeThis part of ISO 2493 specifies procedures to measure the bending resistance of paper and paperboard.Th
18、is part of ISO 2493 is used to determine the bending moment required to deflect the free end of a 38 mm wide vertically clamped specimen by 15 when the load is applied at a bending length of 50 mm. For boards that tend to be permanently deformed if bent through 15, the half bending angle, i.e. 7,5,
19、can be used. The bending resistance is expressed in terms of the bending moment and parameters set by the manufacturer of the Taber-type tester.The method is primarily used for papers with a high grammage.NOTE This part of ISO 2493 does not cover the low-range version of the Taber-type instrument th
20、at uses a bending length of 10 mm(Reference 5).2 Normative referencesThe following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any a
21、mendments) applies.ISO 186, Paper and board Sampling to determine average qualityISO 187, Paper, board and pulps Standard atmosphere for conditioning and testing and procedure for monitoring the atmosphere and conditioning of samples3 Terms and definitionsFor the purposes of this document, the follo
22、wing terms and definitions apply.3.1bending momentMmoment required to bend a rectangular test piece clamped at one end, the moment being measured under the conditions specified in this part of ISO 2493NOTE Bending moment is expressed in millinewton metres (mNm).3.2bending resistanceBmean bending mom
23、ent required to bend a rectangular test piece fastened at one end in a clamp, the bending moment being measured under the conditions specified in this part of ISO 2493NOTE Bending resistance is expressed in millinewton metres (mNm). ISO 2011 All rights reserved 1BS ISO 2493-2:20113.3bending angleang
24、le through which the clamp rotates while moving from its initial position to the position at which the bending resistance is measuredNOTE The bending angle is 15 or 7,5 (see Clause 10).3.4bending lengthconstant radial distance between the clamp and the position on the test piece at which the force i
25、s applied3.5bending resistance indexbending resistance divided by the grammage to the third power4 PrincipleA test piece of defined dimensions is bent through a specified bending angle (3.3) using a specific type of testing instrument. The resulting bending moment is read from the instrument scale.5
26、 Apparatus5.1 Bending resistance tester (see Figure 1), consisting of the following components. 5.1.1 Pendulum, P, rotating around a centre-point, CP, on low-friction bearings, carrying a clamp, C, that has two screws for holding and centring the test piece, TP. At the high end, a centre-line, L, is
27、 engraved that coincides with the centre of the test piece. At the lower end of the pendulum is a stud, S1, to which weights may be attached and that loads the pendulum at a distance of 100,0 mm 0,1 mm from the centre-point. Without added weights, the loading is 10,000 g 0,001 g.5.1.2 Vertical disc,
28、 VD, rotating around the centre-point, CP, and driven by a motor, carries two driving arm attachments, DAA, so located as to provide the test piece, TP, with a cantilevered loading length via two driving arms, DA. The bending length (3.4) is 50,0 mm 0,1 mm. The driving arms are adjustable by means o
29、f screws which enables testing of test pieces of different thicknesses. The ends of the driving arms have rollers as means of transmitting the force to the test piece. It is possible to adjust the length of the arms so that the distance between the test piece and each roller is 0,33 mm 0,03 mm.On th
30、e edge of the upper part of the disc, a centre-line mark is engraved. Two reference lines are engraved on the periphery of the vertical disc, VD, at an angular distance of 7,5 and 15 on both sides of the centre-line mark.A driving mechanism drives the vertical disc, VD, at a nominal constant rate wh
31、ich is allowed to vary between 170 and 210 per minute.5.1.3 Fixed annular disc, FAD, located around the periphery of the vertical disc, VD. The fixed annular disc has a scale from 0 to 100 on both sides of a centre-line mark, zero. The scale shows the bending moment required to bend the test piece t
32、o the right or to the left. (For clarity, only the scale marks 0, 20 and 40 are shown in Figure 1.)5.1.4 Stand, to support the pendulum, P, the vertical disc, VD, and the fixed annular disc, FAD, equipped with a means for levelling the instrument.5.1.5 Various loading weights, in stiffness units def
33、ined by the manufacturer to be mounted on the stud, S1, to give a maximum bending moment of 490 mNm.ISO 2493-2:2011(E)2 ISO 2011 All rights reservedBS ISO 2493-2:20115.2 Preparation of apparatusPlace the instrument on a firm, flat surface. Set the vertical disc, VD, at zero and place a chosen weight
34、, W, on the stud, S1. Close the clamp, C, so that the faces meet on the centre-line of the pendulum. Level the instrument so that the pendulum is vertical.Displace the pendulum by 15 and release it to check the bearing friction. It should make at least 20 complete swings before coming to rest.KeyVD
35、vertical disc DAA driving arm attachmentsP pendulum DA driving armsTP test piece FAD fixed annular discC clamp S 0 reference line stiffness 0CP centre-point S 20 reference line stiffness 20S1 stud S 40 reference line stiffness 40A 7,5 reference line, 7,5 deflection L centre-line of the pendulumA 15
36、reference line, 15 deflectionFigure 1 Taber-type tester6 CalibrationCalibrate the instrument and check the accuracy of the apparatus at regular intervals. The method of calibration depends on the type of instrument and shall be done by following the manufacturers instructions.NOTE Spring-steel test
37、pieces are commonly supplied by the manufacturer of the instrument for calibration purposes.ISO 2493-2:2011(E) ISO 2011 All rights reserved 3BS ISO 2493-2:20117 SamplingIf the tests are being made to evaluate a lot, the sample shall be selected in accordance with ISO 186. If the tests are made on an
38、other type of sample, make sure that the test pieces taken are representative of the samples received.8 ConditioningCondition the samples of paper or board as specified in ISO 187. Keep them in the conditioning atmosphere throughout the test procedure.9 Preparation of test piecesCarry out the prepar
39、ation of test pieces and the testing in the same conditioning atmosphere as that used to condition the samples.If the bending resistance index (3.5) is required, determine the grammage in accordance with ISO 5361.As required, cut a sufficient number of test pieces, 38,0 mm 0,2 mm wide by 70 mm 1 mm
40、long, with the length parallel to the machine direction, to enable 5 valid tests to be performed in this direction; and/or cut another set of test pieces with the length parallel to the cross-direction to enable 5 valid tests to be performed in this direction.Avoid folds, creases, visible cracks or
41、other defects in the area to be tested. If watermarks are present, this shall be noted in the test report.Highly twisted and curled test pieces may give unreliable results. It is not possible to straighten curled or twisted samples without damaging the material.10 ProcedurePlace a test piece in the
42、clamp, C, with one end approximately level with its top edge and the other end between the rollers at the end of the driving arms, DA.With the two clamping screws of the clamp, C, align the test piece with the centre-line, L, of the pendulum.The pressure of the clamping screws may affect the test re
43、sults. It should be firm enough to hold the test piece, but not so firm as to compress or deform it. The test piece should not be restrained at the free end except by the friction imposed on the surfaces of the free end of the test piece by the driving arms, DA.Adjust the rollers at the end of the d
44、riving arms, DA, so that they are just in contact with the test piece. Adjust the length of one of the driving arms, DA, so that the distance between the test piece and the roller is 0,33 mm 0,03 mm.NOTE 1 It is not necessary for the pendulum to balance at zero with the undeflected test piece in pla
45、ce. Curvature of the test piece will result in a difference between the readings for deflection in the two directions. Readings taken in the two directions are averaged to give the stiffness of the test piece.Switch on the motor to rotate the vertical disc, VD, to the left and thus deflect the test
46、piece until the centre-line mark, L, on the pendulum is aligned with the 15 mark on the vertical disc VD.Record the scale reading on the fixed annular disc, FAD, and immediately return the loading disc to zero. Take a similar reading by deflecting the test piece to the right. As required, test at le
47、ast five machine direction (MD) test pieces and/or at least five cross-direction (CD) test pieces to obtain five valid results, i.e. ten valid readings, for each required direction.If the maximum force is obtained before the test piece has been bent through the bending angle 15 (3.3), or a break, ki
48、nk or crease is observed, the test result should be discarded. If more than 10 % of the test pieces cut in a particular direction of interest (machine direction or cross-direction) exhibit this behaviour, use a bending angle of 7,5 for this test piece direction. If so, the bending angle shall be rep
49、orted.ISO 2493-2:2011(E)4 ISO 2011 All rights reservedBS ISO 2493-2:2011IMPORTANT The result obtained at a 7,5 bending angle cannot be converted to that of a 15 bending angle by multiplying by two, since the relationship is not directly proportional to the bending angle.NOTE 2 The tendency for the paper to be deformed in an unacceptable way increases with increasing thickness. The exact thickness for using the bending angle 7,5 cannot be stated.11 Calculation11.1 Bending momentCalculate the
