BS ISO 15361-2001 Pulps Determination of zero-span tensile strength wet or dry《纸浆 在湿润或干燥条件下对零档抗张强度的测定》.pdf

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1、BRITISH STANDARD BS ISO 15361:2000 Pulps Determination of zero-span tensile strength, wet or dry ICS 85.040 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBS ISO 15361:2000 This British Standard, having been prepared under the direction of the Sector Committee for Materials an

2、d Chemicals, was published under the authority of the Standards Committee and comes into effect on 15 August 2001 BSI 08-2001 ISBN 0 580 37943 4 National foreword This British Standard reproduces verbatim ISO 15361:2000 and implements it as the UK national standard. The UK participation in its prepa

3、ration was entrusted to Technical Committee PAI/11, Test methods for paper, board and pulps, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international public

4、ations referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue A British Standard does not purport to include all the necessary provis

5、ions 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. aid enquirers to understand the text; present to the responsible international/European committee any enquiries

6、on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to v, a blank page, p

7、ages 1 to 11 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsReference number ISO 15361:2000(E) INTERNATIONAL STANDARD ISO 15361 First edition 2000-03-01 Pulps Determination o

8、f zero-span tensile strength, wet or dry Ptes Dtermination de la rsistance la traction mchoires jointives, l ta thu mi d eo use cISO15361:2000(E) ii ISO 15361:2000(E) iii Contents Page 1 Scope 1 2 Normative references 1 3 Terms and definitions .1 4 Principle2 5 Apparatus .2 6 Sampling.4 7 Preparatio

9、n of test pieces.4 7.1 Introduction4 7.2 Pretreatment of sample.4 7.3 Preparation of test pieces to be tested as dry or rewetted .5 7.4 Rewetting of test pieces5 7.5 Preparation of never-dried test pieces 5 8 Procedure .6 8.1 Calibration 6 8.2 Determination.7 8.3 Test on reference material 7 9 Expre

10、ssion of results 7 9.1 Reporting of results.7 9.2 Zero-span tensile strength8 9.3 Zero-span tensile index.8 10 Precision.8 11 Test report 9 Annex A (normative) Alternative equipment for straightening fibres .10 Bibliography11ISO 15361:2000(E) iv Foreword ISO (the International Organization for Stand

11、ardization) is a worldwide federation of national standards bodies (ISO member bodies). 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

12、to be represented on that committee. International organizations, governmental and non-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 St

13、andards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. 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

14、 casting a vote. Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. International Standard ISO 15361 was prepared by Technical Committee I

15、SO/TC 6, Paper, board and pulps, Subcommittee SC 5, Test methods and quality specifications for pulp. Annex A forms a normative part of this International Standard.ISO 15361:2000(E) v Introduction Tensile strength data at a span length of zero may be used to assess the retention of fibre strength th

16、rough the entire fibre-processing chain, providing opportunities to optimize fibre characteristics and utilization in various paper grades. Tensile strength values determined at a span length of zero contribute to our understanding of finished sheet strength and are of increasing importance in measu

17、ring the impact of new pulping, bleaching and papermaking processes on fibre characteristics. The zero-span tensile test may be used to determine the strength of pulp fibres when beaten under laboratory conditions, regardless of the laboratory beating procedure used. Measurement of zero-span tensile

18、 strength, in conjunction with tensile strength as well as other physical properties, is useful in optimizing new fibre-processing techniques and maximizing utilization of new fibre sources such as recycled fibres. Papers referenced in the bibliography give further information on the use of zero-spa

19、n tensile measurements. The clamping pressure utilized in zero-span testing ensures a maximum clamping effect but cannot totally prevent micro-slippage, whereby the tensile load transmitted in the clamped fibres is dissipated by frictional shear into the clamping jaws. This micro-slippage means that

20、 the ends of some fibres will slip out from beneath the clamping jaw, thereby diminishing the number of fibres carrying the load at tensile failure. In addition, if kinks in fibres are not removed in the beating process, test results may be diminished. For these reasons, careful interpretation of th

21、e zero-span tensile strength value should be exercised in order to separate effects due to the relative number of fibres which are carrying the load at failure, and the effects due to the tensile strength of the individual fibres present in the aggregate. The zero-span strength values may be differe

22、nt if the samples are tested dry and conditioned, rewetted or wet (never dried).INTERNATIONAL STANDARD ISO 15361:2000(E) 1 Pulps Determination of zero-span tensile strength, wet or dry 1 Scope This International Standard specifies the procedure for determining the tensile strength of laboratory shee

23、ts at a test span which is initially zero. It is applicable to all kinds of fibres, including recycled fibres. The laboratory sheets can be tested either dry, rewetted, or never dried. 2 Normative references The following normative documents contain provisions which, through reference in this text,

24、constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent

25、 editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 187, Paper, board and pulps Standard atmosphere for conditioning a

26、nd testing and procedure for monitoring the atmosphere and conditioning of samples. ISO 287, Paper and board Determination of moisture content Oven-drying method. ISO 536, Paper and board Determination of grammage. ISO 1924-2, Paper and board Determination of tensile properties Part 2: Constant rate

27、 of elongation method. ISO 5263, Pulps Laboratory wet disintegration. ISO 5264-1, Pulps Laboratory beating Part 1: Valley beater method. ISO 5264-2, Pulps Laboratory beating Part 2: PFI mill method. ISO 5269-1, Pulps Preparation of laboratory sheets for physical testing Part 1: Conventional sheet-fo

28、rmer method. ISO 5269-2, Pulps Preparation of laboratory sheets for physical testing Part 2: Rapid-Kthen method. ISO 7213, Pulps Sampling for testing. 3 Terms and definitions For the purposes of this International Standard, the following terms and definitions apply. 3.1 tensile strength maximum forc

29、e per unit width that a test piece of the sample will withstand before breaking under the conditions defined in ISO 1924-2ISO 15361:2000(E) 2 3.2 zero-span shortest possible span between the clamps that hold the sample; when clamps are adjusted to zero-span, a beam of light aimed between the two cla

30、mps is completely interrupted 3.3 zero-span tensile strength tensile strength value measured using an appropriate instrument, with the clamps adjusted to zero-span, under conditions specified in this International Standard 3.4 zero-span tensile index zero-span tensile strength divided by the grammag

31、e NOTE Either conditioned or oven-dry grammage may be used in the calculation, and should be reported. 4P r i n c i p l e From a pulp suspension, laboratory sheets or wet test pieces are formed. They can be tested wet (i.e. never dried), dried (as conditioned) or rewetted. The test pieces are clampe

32、d in a tensile-testing instrument where the clamps are adjusted to zero-span and the test pieces are strained to break. The maximum force at rupture is measured and the zero-span tensile strength is calculated. 5 Apparatus 5.1 Tensile strength tester, complying with the following requirements. 5.1.1

33、 Clamping device, incorporating two clamps with jaws for holding the test piece (see Figure 1). In each clamp, the lower jaw is planar, and is sometimes referred to as the anvil. The upper jaw is similar to the lower jaw, except that it includes a tip extending across the entire front width of the j

34、aw and having a minimum dimension perpendicular to the width of at least 0,6 mm. The width of the jaws shall be between 15 mm and 25 mm, however, the exact width used is not critical, but shall be known to a certainty of 0,01 mm. The jaws shall be of identical width to 0,01 mm (see Figure 2). p is t

35、he pressure applied to the test piece by the clamps in the pressurized state. Figure 1 Essential elements for any zero-span tensile testerISO 15361:2000(E) 3 Dimensions in millimetres Figure 2 Suitable arrangement for the clamps There shall be a means for applying a clamping pressure by the clamps o

36、n the test piece. The clamping pressure shall be uniform to 0,1 % across the width of the jaw. The clamping pressure shall be variable between 250 kPa and 1 000 kPa. The clamps shall be in alignment in both the horizontal direction, A, and vertical direction, B (see Figure 3). When the clamps are in

37、 the closed position with no test piece in place, a beam of light aimed to pass between the clamps, is completely interrupted. The alignment of the clamps is generally set by the manufacturer, and is not user- adjustable. In use, however, adherence of one or more fibres to one of the jaws is possibl

38、e, in which case a light beam may not be completely interrupted. This matter shall be dealt with as described in 8.1.2. Figure 3 Spatial alignment of the two clamps 5.1.2 Means of applying an in-plane tensile force within the fibre aggregate in the free span between the clamps, and of measuring the

39、force at failure, complying with the following requirements. The force shall be applied by tending to cause one clamp to move away from the other in such a way that the rate of increase of the force is (25 2) N/s per 10 mm of jaw width. The accuracy of the means used to measure the applied force sha

40、ll be 0,5 % of the measuring range of the tensile strength tester. 5.2 Laboratory sheet former, capable of producing homogeneous isotropic sheets with an oven-dry grammage of 60 g/m 2 3g / m 2 . 5.3 Blotters, couch weight and plane press, for use in production of laboratory sheets and test pieces, a

41、s required in the standard for the sheet former used. (See ISO 5269.)ISO 15361:2000(E) 4 5.4 Device for cutting test pieces, see 7.2. 5.5 Immersion dish or laboratory spray bottle or other suitable device for wetting of test pieces. These are required only if the test piece is to be wetted before te

42、sting. 5.6 Sponge roller, for removal of excess water from the wetted test piece, or alternatively a rectangular block of sponge with a smooth, flat surface and without obvious surface imperfections. This is required only if the test piece is to be wetted before testing. 5.7 Sample inserter, made of

43、 stainless steel or another noncorrosive material, 0,5 mm or less in thickness. This may be used to transport a wet test piece into the jaws of the tester. 5.8 Mould, made of stainless steel or another noncorrosive material, for preparing test pieces when testing never-dried laboratory sheets. For d

44、imensions see 7.3. 5.9 Various items of common laboratory equipment, for determination of grammage of the never-dried samples. See ISO 536. 5.10 Disintegrator, in accordance with ISO 5263. This is needed only when a sample of dry or semi-dry pulp is to be tested. 5.11 Device for mechanical treatment

45、 of fibres, to reduce fibre curl or kinks, if required, such as a laboratory beater or pulper, for example a Valley beater (ISO 5264-1), a PFI mill (ISO 5264-2) or a high-speed blender as described in annex A. 6 Sampling If the result is intended to reflect the quality of a lot of pulp, sampling sha

46、ll be carried out in accordance with ISO 7213. 7 Preparation of test pieces 7.1 Introduction The test method requires a random aggregate of fibres in sheet form for testing. Even when the sample to be tested is obtained in sheet form, the fibres shall be reduced to a slurry and then reformed into a

47、randomly oriented sheet, unless they are in the form of a laboratory sheet complying with 7.3. If desired, the fibre slurry may be treated to remove fibre curls or kinks prior to sheet forming, but this shall be reported together with the results. 7.2 Pretreatment of sample For pulps received in a d

48、ry or semi-dry form, disintegrate the pulp in accordance with ISO 5263. Pulp slurries may also be disintegrated as required or agreed. Remove from the slurry the quantity of pulp fibres required for preparation of the laboratory sheets. The exact amount of fibre required will depend upon the sheet-f

49、orming procedure. If the concentration of fibres in the slurry is greater than that required in the following steps, reduce the concentration by adding water. Fibres in mill-produced pulp or mixed/kneaded laboratory pulp are often deformed (curled or kinked). This deformation influences the measured zero-span tensile strength value. If the deformations need to be eliminated, soak the pulp as described in ISO 5263, disintegrate if necessary, and mechanically treat the fibres. An example of a treatment, which may be suita