1、July 2012 Translation by DIN-Sprachendienst.English price group 8No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 85
2、.060!$|,“1899809www.din.deDDIN ISO 3781Paper and board Determination of tensile strength after immersion in water(ISO 3781:2011)English translation of DIN ISO 3781:2012-07Papier und Pappe Bestimmung der breitenbezogenen Bruchkraft nach dem Eintauchen in Wasser(ISO 3781:2011)Englische bersetzung von
3、DIN ISO 3781:2012-07Papier et carton Dtermination de la rsistance la traction aprs immersion dans leau (ISO 3781:2011)Traduction anglaise de DIN ISO 3781:2012-07SupersedesDIN ISO 3781:1994-10www.beuth.deDocument comprises 9 pagesIn case of doubt, the German-language original shall be considered auth
4、oritative.06.12 DIN ISO 3781:2012-07 2 A comma is used as the decimal marker. Contents Page National foreword .3 National Annex NA (informative) Bibliography 3 1 Scope 4 2 Normative references 4 3 Terms and definitions .4 4 Principle 5 5 Apparatus .5 6 Sampling .5 7 Conditioning .5 8 Preparation of
5、test pieces .5 9 Procedure .6 10 Calculation and expression of results .6 10.1 General 6 10.2 Wet tensile strength 6 10.3 Wet tensile strength retention 6 11 Test report 7 Annex A (informative) Precision data .8 Bibliography 9 DIN ISO 3781:2012-07 3 National foreword This standard has been prepared
6、by Technical Committee ISO/TC 6/SC 2 “Test methods and quality specifications for paper and board” (Secretariat: SIS, Sweden). The responsible German body involved in its preparation was the Normenausschuss Papier, Pappe und Faserstoff (Paper, Board and Pulps Standards Committee), Working Committee
7、NA 074-02-03 AA Physikalisch-technische Prfverfahren fr Papier und Pappe. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. DIN shall not be held responsible for identifying any or all such patent rights. The DIN Standards correspon
8、ding to the International Standards referred to in this document are as follows: ISO 186 DIN EN ISO 186 ISO 187 DIN 20187 ISO 1924-2 DIN EN ISO 1924-2 ISO 1924-3 DIN ISO 1924-3 The text of the International Standard ISO 3781:2011, Paper and board Determination of tensile strength after immersion in
9、water was adopted without any modification. Amendments This standard differs from DIN ISO 3781:1994-10 as follows: a) tissue paper and tissue products are now dealt with in DIN EN ISO 12625-5; b) Clause 10 “Calculation and expression of results” has been revised; c) Clause 11 “Test report” has been
10、revised; d) the test method has been verified by interlaboratory testing, see Annex A (informative) “Precision data”; e) the standard has been editorially revised. Previous editions DIN 53112-2: 1974-11, 1985-02 DIN ISO 3781: 1994-10 National Annex NA (informative) Bibliography DIN EN 20187, Paper,
11、board and pulps Standard atmosphere for conditioning and testing and procedure for monitoring the atmosphere and conditioning of samples DIN EN ISO 186, Paper and board Sampling to determine average quality DIN EN ISO 1924-2, Paper and board Determination of tensile properties Part 2: Constant rate
12、of elongation method (20 mm/min) DIN ISO 1924-3, Paper and board Determination of tensile properties Part 3: Constant rate of elongation method (100 mm/min) Paper and board Determination of tensile strength after immersion in water 1 Scope This International Standard specifies a test method for the
13、determination of the wet tensile strength of paper or board after its immersion in water for a specified period. In principle, the method is applicable to both paper and board, provided an appropriate soaking time is agreed between the interested parties. This International Standard is not applicabl
14、e to tissue paper and tissue products or other lightweight, highly absorbent paper which is difficult to handle or of low strength when wet (see ISO 12625-51). NOTE The tensile strength testing is performed using an apparatus operating at a constant rate of elongation of 20 mm/min, as per ISO 1924-2
15、, or 100 mm/min, as per ISO 1924-3. Therefore, depending on which method is chosen, only one or the other of those International Standards is needed for performing the test. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated re
16、ferences, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 186, Paper and board Sampling to determine average quality ISO 187, Paper, board and pulps Standard atmosphere for conditioning and testing and proc
17、edure for monitoring the atmosphere and conditioning of samples ISO 1924-2, Paper and board Determination of tensile properties Part 2: Constant rate of elongation method (20 mm/min) ISO 1924-3, Paper and board Determination of tensile properties Part 3: Constant rate of elongation method (100 mm/mi
18、n) ISO 14487, Pulps Standard water for physical testing 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 wet tensile strength maximum tensile force per unit width that a test piece soaked with water will withstand before breaking in a tensile
19、test ISO 12625-5:2005, definition 3.1 DIN ISO 3781:2012-07 4NOTE It is expressed in kilonewtons per metre. 3.2 wet tensile strength retention ratio of the tensile strength of a wet test piece to that of another test piece from the same sample in the dry, conditioned state NOTE 1 It is expressed as a
20、 percentage. NOTE 2 Adapted from ISO 12625-5:2005, definition 3.2. 4 Principle Immersion in water, for an appropriate period of time, of a test piece of the paper or board being tested, and determination of its wet tensile strength. From the wet tensile strength and the tensile strength in the dry,
21、conditioned state, the wet tensile strength retention is calculated. 5 Apparatus 5.1 Tensile strength testing apparatus, complying with ISO 1924-2 or ISO 1924-3 for dry tensile strength testing. 5.2 Water for soaking: distilled or deionized water as specified in ISO 14487, having the temperature spe
22、cified for conditioning in ISO 187. 6 Sampling If the tests are made to evaluate a lot, select the sample in accordance with ISO 186. If the tests are made on another type of sample, ensure that the test pieces taken are representative of the sample received. 7 Conditioning For testing of dry tensil
23、e strength and for tests which involve soaking for less than 1 h, the specimen and the test pieces shall be conditioned in accordance with ISO 187. Conditioning is not necessary for tests involving soaking for 1 h or longer. If the material has been specially treated (for example, with urea-formalde
24、hyde), care shall be taken to ensure that sufficient time has elapsed after treatment to allow the wet strength to be fully developed before soaking the test pieces. 8 Preparation of test pieces Depending on the method chosen, using an apparatus operating at a constant rate of elongation of 20 mm/mi
25、n or 100 mm/min, prepare test pieces in accordance with ISO 1924-2 or ISO 1924-3 respectively. Prepare a sufficient number of test pieces to enable ten valid wet tensile strength readings in the machine direction (MD) and ten valid readings in the cross direction (CD). If the wet tensile strength re
26、tention is also to be calculated, then ten additional test pieces for determination of the dry tensile strength in the MD and another ten for the CD are required. DIN ISO 3781:2012-07 59 Procedure In the absence of any agreement to the contrary, soak the test pieces until saturated; normally, this m
27、eans a soaking time of 1 h. Use water (5.2) and a suitable shallow dish. Boards and other hard-sized papers may require a soaking time of 24 h or longer to attain a satisfactory degree of saturation. The appropriate soaking time may be selected to simulate particular conditions of use, by agreement
28、between the interested parties. For very absorbent papers, it is recommended that only the centre portion of the test piece be wetted, while the portion held by the clamps remains dry (see ISO 12625-51). After soaking, remove the test pieces from the dish. Lightly blot the first test piece in order
29、to remove surplus water and immediately test it by the method specified in ISO 1924-2 or ISO 1924-3. Repeat for the remaining test pieces. Carry out ten tests in the MD and ten in the CD of the immersed test pieces. If the wet tensile strength retention is also to be calculated, carry out ten additi
30、onal tests in the MD and another ten in the CD of the dry, conditioned test pieces. 10 Calculation and expression of results 10.1 General Calculate and report the wet tensile strength and, if required, the wet tensile strength retention separately for the MD and CD, as follows. 10.2 Wet tensile stre
31、ngth Calculate the wet tensile strength, wet, using Equation (1): wetwetFb (1) where wetF is the mean maximum tensile force, in kilonewtons; b is the width of the dry test piece (15 mm), in metres. Report the wet tensile strength, in kilonewtons per metre, to three significant figures. 10.3 Wet tens
32、ile strength retention If required, calculate the wet tensile strength retention, R, as a percentage of the corresponding value in the dry state using Equation (2): wetRdry100 (2) where wetis the wet tensile strength, in kilonewtons per metre; DIN ISO 3781:2012-07 6dryis the tensile strength in the
33、dry, conditioned state, in kilonewtons per metre. NOTE The calculations for dry tensile strength are given in ISO 1924-2 or ISO 1924-3. 11 Test report The test report shall include the following information: a) reference to this International Standard, i.e. ISO 3781; b) the date and place of testing
34、; c) the complete identification of the sample; d) the soaking time and, if the sample has been conditioned, the conditioning atmosphere used; e) the International Standard used for tensile strength testing, i.e. ISO 1924-2 or ISO 1924-3; f) the wet tensile strength calculated in accordance with 10.
35、2; g) if required, the wet tensile strength retention in accordance with 10.3; h) any deviation from this International Standard or any other circumstance that might have influenced the results. DIN ISO 3781:2012-07 7Annex A (informative) Precision data The estimates of repeatability and reproducibi
36、lity are based on data from the CEPI-CTS (Confederation of European Paper Industries Comparative Testing Service) round 2 in 2010. The calculations have been made according to ISO/TR 24498 2and TAPPI Test method T 1200 sp-07 3. The repeatability limit, r, can be calculated from within lab1, 9 6 2rs
37、. The reproducibility limit, R, can be calculated as 22within lab between lab1, 9 6 2Rss . The repeatability standard deviation reported in Table A.1 is the “pooled” repeatability standard deviation, i.e. the standard deviation is calculated as the root-mean-square of the standard deviations of the
38、participating laboratories. This differs from the conventional definition of repeatability in ISO 5725-14. The repeatability and reproducibility (see Table A.2) limits reported are estimates of the maximum difference which should be expected in 19 of 20 instances, when comparing two test results for
39、 material similar to those described under similar test conditions. These estimates may not be valid for different materials or different test conditions. Repeatability and reproducibility limits are calculated by multiplying the repeatability and reproducibility standard deviations by 2,77. NOTE 2,
40、77 1,96 2 , provided that the test results have a normal distribution and that the standard deviation, s, is based on a large number of tests. Table A.1 Estimation of repeatability of the test method from CEPI-CTS Material Number of laboratories Mean value N/m Standard deviation, srN/m Coefficient o
41、f variation, CoVr% Repeatability limit, r N/m Sample level 1 10 531 26,6 5,0 73,7 Sample level 2 10 1 777 67,0 3,8 185,7Table A.2 Estimation of reproducibility of the test method from CEPI-CTS Material Number of laboratories Mean value, N/m Standard deviation, sRN/m Coefficient of variation, CoVR% R
42、eproducibility limit, R N/m Sample level 1 10 531 37,3 7,0 103,5Sample level 2 10 1 777 81,3 4,6 225,3 DIN ISO 3781:2012-07 8Bibliography 1 ISO 12625-5, Tissue paper and tissue products Part 5: Determination of wet tensile strength 2 ISO/TR 24498:2006, Paper, board and pulps Estimation of uncertaint
43、y for test methods 3 TAPPI Test method T 1200 sp-07, Interlaboratory evaluation of test methods to determine TAPPI repeatability and reproducibility 4 ISO 5725-1:1994, Accuracy (trueness and precision) of measurement methods and results Part 1: General principles and definitions DIN ISO 3781:2012-07 9
