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1、BRITISH STANDARD BS EN 21974:1994 ISO 1974:1990 Incorporating Amendment No. 1 Paper Determination of tearing resistance (Elmendorf method) The European Standard EN 21974:1994 has the status of a British Standard UDC 676.2.017.4:620.176.245 Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 03 09:26
2、:48 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN 21974:1994 This British Standard, having been prepared under the direction of the Paper and Printing Standards Policy Committee, was published under the authority of the Board of BSI and comes into effect on 31 July 1990 BSI 09-1999 First publishe
3、d May 1969 Second edition July 1990 The following BSI references relate to the work on this standard: Committee reference PAM/11 Draft for comment 88 41989 DC ISBN 0 580 18780 2 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Paper and P
4、rinting Standards Policy Committee (PAM/-) to Technical Committee PAM/11, upon which the following bodies were represented: British Fibreboard Packaging Association British Paper and Board Industry Federation (PIF) British Printing Industries Federation British Telecommunications plc Envelope Makers
5、 and Manufacturing Stationers Association Her Majestys Stationery Office Man-made Fibres Producers Committee Ministry of Defence Paper Sack Development Association Ltd. PIRA (the Research Association for the Paper and Board, Printing and Packaging Industries) Post Office Society of British Printing
6、Ink Manufacturers University of Manchester Institute of Science and Technology Amendments issued since publication Amd. No.DateComments 8176December 1994 Indicated by a sideline in the margin Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 03 09:26:48 GMT+00:00 2006, Uncontrolled Copy, (c) BSI B
7、S EN 21974:1994 BSI 09-1999i Contents Page Committees responsibleInside front cover National forewordii Foreword2 1Scope3 2Normative references3 3Definitions3 4Principle3 5Apparatus3 6Sampling3 7Conditioning3 8Preparation of test pieces3 9Procedure4 10Calculation and expression of results4 11Precisi
8、on5 12Test report5 Annex A (normative) Description, adjustment and maintenance of single tear testers6 Annex B (normative) Calibration of apparatus8 Annex C (informative) Units9 Annex ZA (normative) Normative references to international publications with their relevant European publications10 Figure
9、 A.1 Elmendorf-type tearing apparatus7 Publications referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 03 09:26:48 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN 21974:1994 ii BSI 09-1999 National foreword This British Standard has been prepared under the direction of
10、 the Paper and Printing Standards Policy Committee. It is identical with ISO 1974:1990 “Paper Determination of tearing resistance (Elmendorf method)”, published by the International Organization for Standardization (ISO). It is a revision of BS 4468:1969 which is withdrawn. In 1994 the European Comm
11、ittee for Standardization (CEN) accepted ISO 1974:1990 as European Standard EN 21974:1994. As a consequence of implementing the European Standard this British Standard is renumbered as BS EN 21974:1994 and any reference to BS 4468 should be read as a reference to BS EN 21974. A British Standard does
12、 not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references International StandardCorresponding British Sta
13、ndard ISO 186:1985BS 3430:1986 Method for sampling to determine the average quality of paper and board (Identical) ISO 187:1977BS 3431:1973 Method for the conditioning of paper and board for testing (Technically equivalent) ISO 536:1976BS 3432:1980 Method for determination of grammage of paper and b
14、oard (Identical) Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 10, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicate
15、d in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 03 09:26:48 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 21974 June 1994 UDC 676.2.017.4:620.176.245 Descriptors: Paper, tests, tear tests Englis
16、h version Paper Determination of tearing resistance (Elmendorf method) (ISO 1974:1990) Papier Dtermination de la rsistance au dchirement (Mthode Elmendorf) (ISO 1974:1990) Papier Durchreissversuch (Elmendorf methode) (ISO 1974:1990) This European Standard was approved by CEN on 1994-06-27. CEN membe
17、rs are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on applicatio
18、n to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the sa
19、me status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardizat
20、ion Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1994 Copyright reserved to CEN members Ref. No. EN 21974:1994 E Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 03 09:26:48 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 219
21、74:1994 BSI 09-1999 2 Foreword This European Standard has been taken over by CEN/TC 172, Pulp, paper and board, from the work of ISO/TC 6, Paper, board and pulps, of the International Organization for Standardization (ISO). This document was submitted to the Unique Acceptance Procedure (UAP) and was
22、 approved without any modification. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by December 1994, and conflicting national standards shall be withdrawn at the latest by December 1994. In accordan
23、ce with the CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. License
24、d Copy: sheffieldun sheffieldun, na, Fri Nov 03 09:26:48 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 21974:1994 BSI 09-19993 1 Scope This International Standard specifies a method for determining the tearing resistance of paper. It can also be used for light boards if the tearing resistance is wit
25、hin the range of the instrument. This International Standard does not apply to corrugated fibreboard, but it may be applied to the components of such boards. It is not suitable for determining the cross-direction tearing resistance of highly directional paper (or board). 2 Normative references The f
26、ollowing standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are
27、encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 186:1985, Paper and board Sampling to determine average quality. ISO 187:1977, Paper and board Co
28、nditioning of samples. ISO 536:1976, Paper and board Determination of grammage. 3 Definitions For the purposes of this International Standard, the following definitions apply. 3.1 tearing resistance the mean force required to continue the tearing started by an initial cut in a single sheet of paper
29、(or board). If the initial cut is in the machine direction, the result is given as machine-direction tearing resistance; similarly, if the initial cut is in the cross direction, the result is given as cross-direction tearing resistance. The result is expressed in millinewtons (mN) 3.2 tear index the
30、 tearing resistance of the paper (or board) divided by its grammage. The result is expressed in millinewton square metres per gram (mNm2/g) 4 Principle A test piece of superimposed sheets (normally four), with a specified pre-cut slit, is torn through a fixed distance using a pendulum which applies
31、the tearing force by moving in a plane perpendicular to the initial plane of the test piece. The work done in tearing the test piece is measured by the loss in potential energy of the pendulum. The average tearing force (work done divided by the total distance torn) is indicated by a scale on the pe
32、ndulum or a digital display. The tearing resistance of the paper is determined from the average tearing force and the number of sheets comprising the test piece. 5 Apparatus 5.1 Elmendorf-type tear tester, of suitable capacity complying with the requirements specified in Annex A. NOTE 1Some apparatu
33、s may be equipped with digital indication of tearing resistance. Such apparatus normally replaces the friction pointer system with a transducer for sensing the angular movement of the pendulum. Transducer outputs are electrically processed to give a direct digital read-out of average tearing resista
34、nce. In other respects this type of apparatus conforms to the requirements of Annex A. NOTE 2Under the conditions of this test, the total work done by the pendulum includes the work done in tearing the paper and also the work done in lifting and bending the test piece and overcoming friction between
35、 the torn edges of the test piece. With some instruments the total work done also includes overcoming frictional forces due to the test piece rubbing on the pendulum during the test. This is a major source of error on such apparatus, and apparatus on which this occurs are not considered suitable for
36、 testing in accordance with this International Standard. Instruments, modified by a suitable cut out to avoid this problem are available. 5.2 Augmenting masses or interchangeable pendulums to increase the tearing force capacity of the apparatus. 5.3 Means for preparing the test piece: may comprise a
37、 suitable die, guillotine or template and knife. 6 Sampling Sample in accordance with ISO 186. 7 Conditioning Condition the sample in accordance with ISO 187. 8 Preparation of test pieces Prepare the test pieces in the same conditioning atmosphere used to condition the samples. There shall be no fol
38、ds, creases or other visible defects in the area from which the test piece is cut and the test piece shall not include any part of the sample that is less than 15 mm from the edge of the sheet or reel. If watermarks are present, this should be stated in the test report. Licensed Copy: sheffieldun sh
39、effieldun, na, Fri Nov 03 09:26:48 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN 21974:1994 4 BSI 09-1999 Identify the two sides of the paper in a convenient way, for example, side one and side two and, with the same side up, from each specimen cut four rectangular sheets of the same size between 50
40、 mm 2 mm and 76 mm 2 mm wide with edges parallel to the desired test direction and of such a length that after the initial cut has been made either as part of the test piece preparation or by means of the integral knife (see clause A.1), the untorn length is 43,0 mm 0,5 mm long. Assemble the cut she
41、ets into sets of four to make up the test pieces. Alternatively, arrange four specimens with their machine directions parallel and the same sides facing the same way and cut the test piece simultaneously as described above. The untorn length shall be as specified above. The edges of the sheets compr
42、ising the test piece shall be free and not stuck together. NOTE 3The exact test piece dimensions depend on the design of the apparatus clamps used. For certain apparatus the appropriate dimensions are 50 mm wide 63 mm long; for others 50 mm wide 65 mm long or 63 mm wide 76 mm long. A guillotine givi
43、ng the appropriate test piece dimensions is normally supplied with the apparatus. Cut sufficient test pieces to give a minimum of 10 valid tests in each required principal direction of the paper (i.e. a total of at least 40 sheets in each direction). 9 Procedure Carry out the tests in the same condi
44、tioning atmosphere used to condition the samples. Set up and check the instrument as described in Annex A. If necessary, calibrate the apparatus as described in Annex B. Carry out a few tests by the procedure described below in order to select the appropriate pendulum or pendulum/augmenting mass com
45、bination. It is desirable to arrange for the mean readings to fall within the range 20 % to 80 % of the full scale reading, although values based on readings taken outside these limits may be noted in the report. Raise the pendulum to its initial position and secure it by the pendulum release mechan
46、ism. Carefully position the test piece in the clamps so that the slit, if pre-made, is centrally situated between the clamp on the frame and the clamp on the pendulum, and tighten the clamps. Where applicable, operate the knife to produce the required slit. Set the pointer if fitted, against its sto
47、p. Sharply depress the pendulum release mechanism and holding it down, gently catch the pendulum by hand on its return swing without disturbing the position of the pointer, if fitted. Record the scale reading to the nearest scale division for the capacity used. NOTE 4Digital read-out instruments may
48、 have slightly different arrangements for releasing and arresting the pendulum. In such cases follow the manufacturers instructions. Return the pendulum and, if fitted, the pointer to the initial position and remove the torn paper. Repeat this procedure for the other test pieces, orientating them so
49、 that side one faces towards and away from the pendulum alternately. The path of the tear may deviate from the direction of the slit. If the mean deviation exceeds 10 mm in one or two out of 10 tests, reject these results and carry out further tests to bring the number of satisfactory tests up to 10. If in more than two of the test pieces the deviation exceeds 10 mm, include the results and state the fact in the test report. If, instead of tearing in the normal way, the paper of any test piece peels apart so as to expose a wide band o