© ISO 2016 Tissue paper and tissue products — Part 4 Determination of tensile strength, stretch at maximum force and tensile energy absorption Papier tissue et produits tissue — Partie 4 Détermination[.]
INTERNATIONAL STANDARD ISO 12625-4 Second edition 2016-12-01 Tissue paper and tissue products — Part 4: Determination of tensile strength, stretch at maximum force and tensile energy absorption Papier tissue et produits tissue — Partie 4: Détermination de la résistance la rupture par traction, de l’allongement la force maximale et de l’absorption d’énergie la rupture par traction Reference number ISO 12625-4:2016(E) I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n © ISO 2016 ISO 12625-4:2016(E) COPYRIGHT PROTECTED DOCUMENT © ISO 2016, Published in Switzerland All rights reserved Unless otherwise specified, no part o f this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission Permission can be requested from either ISO at the address below or ISO’s member body in the country o f the requester ISO copyright o ffice Ch de Blandonnet • CP 401 CH-1214 Vernier, Geneva, Switzerland Tel +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org ii I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n ISO 12625-4:2016(E) Contents Page Foreword iv Scope Normative references Terms and definitions Principle Apparatus Conditioning Preparation of test pieces 7.1 7.2 7.3 General Dimensions Number of test pieces 9.1 9.2 9.3 9.4 General Tensile strength Tensile index Stretch at maximum force Procedure Calculation 9.5 9.6 Tens ile energy ab s o rp tio n Tens ile energy ab s o rp tio n index 10 Test report Annex A (informative) Precision Bibliography © ISO 2016 – All rights reserved I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n iii ISO 12625-4:2016(E) Foreword I SO (the I nternational O rganiz ation for Standardiz ation) is a worldwide federation of national s tandards bodies (ISO member bodies) The work o f preparing International Standards is normally carried out through ISO technical committees Each member body interested in a subject for which a technical committee has b een es tablished has the right to b e represented on that committee I nternational organi zation s , governmental and non- governmental, in liaison with I SO, al so take p ar t in the work ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters o f elec trotechnical s tandardi z ation T he procedures used to develop this cument and those intended for its fur ther maintenance are describ ed in the I SO/I E C D irec tives , Par t I n p ar ticu lar the different approval criteria needed for the di fferent types o f ISO documents should be noted This document was dra fted in accordance with the editorial ru les of the I SO/I E C D irec tives , Par t (see www iso org/direc tives) Attention is drawn to the possibility that some o f the elements o f this document may be the subject o f patent rights ISO shall not be held responsible for identi fying any or all such patent rights Details o f any patent rights identified during the development o f the document will be in the Introduction and/or on the I SO l is t of p atent declarations received (see www iso org/p atents) Any trade name used in this document is in formation given for the convenience o f users and does not cons titute an endors ement For an explanation on the meaning o f ISO specific terms and expressions related to formity assessment, as well as information about I SO ’s adherence to the World Trade O rganization ( WTO) principles in the Technical B arriers to Trade (TB T ) see the following URL: www.iso.org/iso/foreword html This document was prepared by the European Committee Standardization (CEN) Technical Committee C E N/ TC 172 , Pulp, paper and board, in col lab oration with I SO Technical C ommittee TC , Paper, board and pulps, Sub committee SC , Test methods and quality specifications for paper and board, in accordance with the Agreement on technical co op eration b etween I S O and C E N ( Vienna Agreement) This second edition cancels and replaces the first edition (ISO 12625-4:2005), which has been technically revised with the following changes: a) “stretch at break” was replaced by “stretch at maximum force”; b) , a more detailed description o f the preparation o f the test pieces was included; in C laus e c) the number o f test pieces required has been clarified with more detailed in formation; , the procedure for the measurement was clarified; d) in C laus e e) in C laus e 10 f , additional in formation is to be included in the test report; ) this document has been editorially updated A lis t of al l p ar ts in the I SO 62 series can b e found on the I SO web s ite iv I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n INTERNATIONAL STANDARD ISO 12625-4:2016(E) Tissue paper and tissue products — Part 4: Determination of tensile strength, stretch at maximum force and tensile energy absorption Scope This c u ment ma xi mu m force s p e ci fie s a te s t me tho d for the de term i nation o f the ten s i le s treng th , s tre tch at a nd ten s i le energ y ab s or p tion o f ti s s ue p ap er and ti s s ue pro duc ts I t u s e s a ten s i le - testing apparatus operating with a constant rate of elongation I t a l s o s p e c i fie s the me tho d o f c a lc u lati ng the ten s i le i nde x a nd the ten s i le energ y ab s orp tion i ndex In cases where impurities and contraries have to be determined, ISO 15755 [6] applies for these detections in tissue paper and tissue products Normative references T he fol lowi ng c u ments are re ferre d to i n the tex t i n s uch a way th at s ome or a l l o f thei r content s titute s re qu i rements o f th i s c u ment For date d re ference s , on ly the e d ition cite d appl ie s For u ndate d re ference s , the late s t e d ition o f the re ference d c ument (i nclud i ng a ny amend ments) appl ie s ISO 186, Paper and board — Sampling to determine average quality ISO 187, Paper, board and pulps — Standard atmosphere for conditioning and testing and procedure 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 7500-1, Metallic materials — Calibration and verification of static uniaxial testing machines — Part 1: Tension/compression testing machines — Calibration and verification of the force-measuring system Terms and definitions ISO 12625-1 f ISO and IEC maintain terminological databases for use in standardization at the following addresses: — IEC Electropedia: available at http://www.electropedia.org/ — ISO Online browsing platform: available at http://www.iso.org/obp For the purp oses o f this cument, the terms and definitions given in and the ol lowing apply 3.1 tensile strength maximum tensile force per unit width that a test piece will withstand before breaking in a tensile test 3.2 tensile index tensile strength (3.1) d ivide d b y gram mage © ISO 2016 – All rights reserved I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n ISO 12625-4:2016(E) 3.3 stretch at maximum force ratio of the elongation of a tes t piece, over its initial length, at the moment when the ma ximum tens i le force is reached during a tens ile tes t N o te to entr y: S tre tch at m a xi mu m force i s e xpre s s e d a s a p ercentage o f the i n iti a l leng th 3.4 tensile energy absorption TEA amou nt o f energ y ab s orb e d p er un it s u r face are a o f a te s t pie ce wh i le b ei ng s tre tche d, u nti l the on s e t o f break (the moment of ma ximum tens i le force) in a tens ile tes t [SOURC E: I SO 62 -1 : 011 , 59] 3.5 tensile energy absorption index tensile energy absorption (3 ) d ivide d b y gram mage [SOURC E: I SO 192 -2 : 0 , ] Principle A tes t piece of tis s ue p ap er or tis s ue pro duc t, of given dimens ions , is s tretched to break at a cons tant rate of elongation us ing a tens i le-tes ting app aratus that meas ures and records the tens ile force as a func tion of the elongation of the tes t piece From the recorded data, the tens ile s trength, the corres p onding s tretch at ma ximum force and the ten s i le energ y ab s orp tion c an b e c a lc u l ate d T he te s t c an b e c a rrie d out b y a ver tic a l or a hori z onta l ten s i le s treng th te s ter P re ci s ion data a re avai lable in Annex A Apparatus 5.1 Tensile-testing apparatus 5.1.1 General T he tens i le-tes ting app aratus shal l b e in accordance with I SO 192 -2 It is cap able of s tretching a tes t piece of tis s ue p ap er or tis s ue pro duc t of given dimens ion s , at a cons tant rate of elongation of (5 ± ) mm/min, and recording the tens i le force as a func tion of elongation on a s trip char t recorder or any e qu iva lent device T he elongation s l l b e re corde d to a n acc u rac y o f ± ,1 m m T he me a s u rement o f the elongation s l l s tar t at a tens ion of (5 ± 1) N/m T he force -me as u ri ng s ys tem sha l l me as u re lo ad s with a n acc u rac y o f ±1 % o f the re ad i ng or ± ,1 N , wh ichever i s gre ater, a nd sha l l b e c a l ibrate d a nd veri fie d to form to the re qu i rements o f I S O 75 0 -1 5.1.2 Means for measuring the area of the force-elongation curve T he tens ile -tes ting app aratus shal l provide a means for meas uring the area b etween the force- elongation c u r ve a nd the elongation a xi s to an acc u rac y o f ± % o f the tr ue va lue as de term i ne d b y numerical integration of the raw data NO T E M o s t mo dern ten s i le tes ters are equ ipp ed with an elec tronic or elec tro -mechanica l integrator that can b e us e d for th i s pur p o s e T he are a c an a l s o b e determ i ned from a graph ic al output of the data on char t p ap er us i ng a plani me ter I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n ISO 62 -4: 01 6(E) Clamps The tensile-testing apparatus shall have two clamps of at least 50 mm in width Each clamp shall be de s igne d to grip the te s t pie ce fi rm ly a long a s traight l i ne acro s s the c aus i ng a ny da mage, a nd sha l l h ave me an s for fu l l adj u s ti ng the cl ampi ng width o f the te s t pie ce, without force T he clamp s shou ld pre ferably grip the te s t pie ce b e twe en a c yl i nd ric a l and a flat s ur face , with the pla ne o f the te s t pie ce ta ngentia l to the c yl i nd ric a l s ur face O ther typ e s o f cla mp s may b e u s e d i f it c an b e en s ure d th at the te s t pie ce e s no t s l ip or s u ffer any da mage duri ng the te s t During the test, the clamping lines shall be parallel to each other within an angle of 1° The clamping lines shall be perpendicular to the direction of the applied tensile force and to the longest dimension of the te s t pie ce to the s ame level o f acc u rac y T he d i s tance b e twe en the cla mpi ng l i ne s (i e the te s t s p a n leng th) s l l b e adj u s te d to (10 ± 1) m m, excep t that a te s t s p an leng th o f (5 ± 1) m m s l l b e u s e d for fi n i s he d p ap er pro duc ts o f wh ich one or b o th o f the d i men s ion s i s i n s u ffic ient to provide a te s t pie ce o f the leng th re qui re d i n NOTE T he Toilet tissue sheets having one or both dimensions of about 98 mm are an example of such a material Cutting device c utti ng device sh a l l be c ap able o f rep e ate d ly c utti ng te s t pie ce s undamaged, straight, smooth and parallel edges 7.2 (5 , ± 0,5) mm wide, with Conditioning Condition the samples according to ISO 187 and keep them in the standard atmosphere throughout the test Conditioning shall be done prior to the preparation of test pieces Preparation of test pieces 7.1 7.1 General If the tests are being made to evaluate a lot, the sample shall be selected in accordance with I S O I f the tes ts are b eing made o n ano ther typ e o f s amp le, make s ure that the s p ecimens taken are rep res entative o f the s amp le E ach tes t p iece s hall b e inherent in the tissue free fro m p er fo ratio ns and faults no t no rmally For converted tissue products, testing shall be done on the product as received, regardless of suitable for use as a test piece 7.1 the numb er o f p lies which are s up p lied as a p ro duct unit Generally, a s ingle finis hed p ro duct s heet is 7.1 Tis s ue that has no t b een co nverted into a finis hed p ro duct s hall b e tes ted as a s ingle p ly unles s otherwise agreed between the parties concerned 7.2 Dimensions Each test piece shall be (50,0 ± 0,5) mm in width and at least 150 mm in length With the exception of tissue paper or tissue products with an embossed pattern over all or part of the surface, the test pieces shall be free of creases, kinks, wrinkles, folds or other thickness variations For fi n i s he d pro duc ts with d i men s ion s or p er foration s wh ich ma ke c utti ng o f a te s t pie ce o f at le as t 150 mm impossible, cut the longest piece possible In such cases, a test span length of (50 ± 1) mm © ISO 2016 – All rights reserved I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n ISO 12625-4:2016(E) for the tensile tester clamps (5.1.3) shall be used This deviation from the normal procedure shall be recorded in the test report 7.3 Number of test pieces Cut at least 10 test pieces in the machine direction and 10 test pieces in the cross direction for the selected specimens, making a total of at least 20 test pieces from each sample of tissue paper or tissue product Procedure 8.1 Ensure that the tensile-testing apparatus is calibrated and check the zero position of the recording device Check that the clamps are aligned to meet the requirements in 5.1.3 8.2 The elongation rate between the clamps shall be kept constant at (50 ± 2) mm/min (5.1) 8.3 Place the test piece in the clamps so that any observable slack is eliminated but the test piece is not placed under any significant strain (5.1) The test piece shall not be clamped with a tension greater than N/m 8.4 Do not touch the test area o f the test piece between the clamps with the fingers Align the test piece as parallel as possible to the pulling direction, tightly clamp the test piece and initiate the test 8.5 Test the test pieces from each sample Record all readings, except for test pieces that break within mm from the clamping line, until 10 valid results are available for each direction I f more than 20 % o f the test pieces cut from a particular specimen break within mm o f the clamping line, reject all the readings obtained for that specimen Inspect the apparatus for formity with the specifications and take the appropriate remedial measures Calculation 9.1 General Calculate and report the results separately for the machine direction and for the cross direction from Formula (1) to Formula (6) 9.2 Tensile strength Calculate the mean maximum tensile force ( F ) in newtons from all the single values (F) available representing acceptable test results Calculate the mean tensile strength ( S ) from Formula (1): S= F × 10 wx where S is the tensile strength, expressed in newtons per metre (N/m); F is the maximum tensile force in newtons (N); wx is the initial width, in millimetres, of the test piece (50 mm) Report the tensile strength in newtons per metre to three significant figures I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n (1) ISO 12625-4:2016(E) 9.3 Tensile index Calculate the tensile index, , from Formula (2): I I = (2) S g where I i s the ten s i le i ndex, expre s s e d i n new ton me tre s p er gram (Nm/g) ; i s the ten s i le s treng th i n new ton s p er me tre (N/m) ; S is the grammage, in grams per square metre (g/m2 ), determined according to ISO 12625-6 g Rep or t the ten s i le i ndex i n new ton me tre s p er gram to th re e s igni fic a nt figure s 9.4 Stretch at maximum force Calculate the mean elongation at break corresponding to the stretch of the test piece at the moment when the maximum force is reached Calculate the stretch at maximum force, , from Formula (3): A A ε = × 100 (3) l where force A i s the me an s tre tch at ma xi mu m ε i s the me an elongation at ma xi mu m i n p ercentage (%) ; force i n m i l l i me tre s (m m) ; is the length of the test piece between the clamps, before elongation (see 5.1.3), in millimetres (mm) l Rep or t the re s u lt to the fi rs t de c i ma l place 9.5 Tensile energy absorption Determine the area under the force-elongation curve up to the point of maximum tensile force and , from Formula (4): c a lc u late the ten s i le energ y ab s or p tion, Z Z = E w× l (4) × 000 and the me an ten s i le energ y ab s orp tion, Z Z= , from Formula (5): ∑Z (5) n where Z i s the ten s i le energ y ab s orp tion b y a s i ngle te s t pie ce du ri ng the te s t unti l ma xi mu m j ou le s p er s quare me tre ( J/m Z E i s the me an ten s i le energ y ab s or p tion i n j ou le s p er s quare me tre ( J/m i s the work, i n m i l l ij ou le s , e qu iva lent to the a re a u nder the © ISO 2016 – All rights reserved I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n force, in ); ); force/elongation c u r ve (mJ ) ; ISO 12625-4:2016(E) w i s the i niti a l width , i n m i l l i me tre s , o f the te s t pie ce (5 m m) ; l i s the i niti a l te s t leng th, i n m i l l i me tre s (s ta nda rd 10 m m) ; n i s the nu mb er o f s i ngle va lue s o f the ten s i le energ y ab s orp tion Rep or t the me an ten s i le energ y ab s orp tion i n j ou le s p er s quare me tre ( J/m ) to the fi rs t de c i ma l place 9.6 Tensile energy absorption index C a lc u late the ten s i le energ y ab s or p tion i ndex, IZ = IZ, us ing Formula (6) : Z (6) g where IZ Z g i s the ten s i le energ y ab s or p tion i ndex, i n j ou le s p er gra m ( J/g) ; i s the me an ten s i le energ y ab s orp tion, i n j ou le s p er s quare me tre ( J/m ) ; is the grammage, in grams per square metre (g/m ) , determined in accordance with I SO 62 - Rep or t the ten s i le energ y ab s or p tion i nde x, i n j ou le s p er gra m, to the fi rs t de c i ma l place 10 Test report T he tes t rep or t shal l include the fol lowing information: a) a re ference to th i s c u ment, i e I S O 62 - 4; b) the date and place o f te s ti ng; c) the de s crip tion and identi fic ation o f the s a mple (for exa mp le, pro duc t c ate gor y a nd d i men s ion s u nder te s t) ; d) the numb er of s ingle values used to calcu late the tens i le s trength, elongation at ma ximum force and ten s i le energ y ab s orp tion; e) the me a n ten s i le s treng th i n mach i ne a nd c ro s s d i re c tion i n new ton s p er me tre to th re e s ign i fic a nt figu re s; f) the s tand ard devi ation or co e ffic ient o f va riation to two s igni fic a nt figure s; g) the mean s tretch at ma ximum force, in p ercentage, in the machine and cros s direc tion, rounded to the fi rs t de c i ma l place, s tandard devi ation or co e fficient o f va riation; h) the ten s i le energ y ab s or p tion i n mach i ne a nd cro s s d i re c tion, i n j ou le s p er s qua re me tre, rounde d to the fi rs t de c i ma l; i) any devi ation from th i s c u ment and any o ther c i rc u m s tance s that may have a ffe c te d the te s t re s u lts; j) the cond ition i ng atmo s phere u s e d I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n ISO 62 -4: 01 6(E) Annex A (informative) Precision A.1 General The data have been obtained from CEPI-CTS, the Comparative Testing Service of the Confederation f f laboratories Two samples were tested according to this document The data for tensile strength are presented in A.2 The data for stretch at maximum force are presented in A.3 f Table A.1 to Table A.4 o f Eu rop e a n Pap er I ndu s trie s T he re s u lts T he rep e atabi l ity a nd repro duc ibi l ity re s u lts P re c i s ion data for are rom a te s t rou nd p er orme d in 01 b y qua l i fie d rom the te s t are rep or te d i n ten s i le energ y ab s or p tion i s no t avai lable at the moment The calculations were made according to ISO/TR 24498 [7] and TAPPI T 1200 sp-07[8] Table A.1 and Table A.3 standard deviation, which means that the standard deviation is calculated as the root-mean-square of f ff f [3] f T he rep e atabi l ity s ta nda rd devi ation rep or te d i n the s ta nda rd deviation s o o the p a r ticip ati ng lab oratorie s T h i s d i i s the “p o ole d” rep e atabi l ity ers rom the conventiona l defi n ition rep e atabi l ity i n I S O -1 T he rep e atabi l ity a nd repro ducibi l ity l i m its rep or te d a re e s ti mate s o f the ma xi mum d i fference wh ich should be expected in 19 of 20 instances, when comparing two test results for material similar to those de s c rib e d under s i m i la r te s t cond ition s T he s e e s ti mate s may no t b e va l id for d i fferent materi a l s or d i fferent te s t cond ition s Rep e atabi l ity and repro duc ibi l ity l i m its a re c a lc u l ate d b y mu ltiplyi ng the rep e atabi l ity and repro ducibi l ity s tandard devi ation s b y ,7 NO TE T he rep e atab i l ity s ta nda rd de vi atio n a nd the with i n-l ab orator y s ta nd a rd de vi ation a re identic a l H owe ver, the rep ro duc ib i l ity s ta nda rd de viation i s no t the s a me a s b e twe en-l ab orator ie s s ta nda rd de vi atio n T he rep ro duc ib i l ity s ta nd a rd de vi ation i nclude s b o th the b e twe en-l ab orator ie s s ta nd a rd de vi ation a nd the s ta nd a rd de viation with i n a l ab orato r y, vi z : s repeatability but s 2 = s with in lab reproducibility ? 2 = s with + s between in lab lab ? ? NOTE 2,77 = 1,96 , provided that the test results have a normal distribution and that the standard deviation, s, is based on a large number of tests © ISO 2016 – All rights reserved I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n ISO 12625-4:2016(E) A.2 Tensile strength Table A.1 — Repeatability results o f an interlaboratory test by qualified laboratories (tensile strength) Sample Number of laboratories Mean tensile strength Repeatability standard deviation Coe fficient o f variation Repeatability limit sr CV, r r N/m N/m % N/m A 11 121 9,0 7,4 25 B 10 643 27 4,2 74 Table A.2 — Reproducibility results o f an interlaboratory test by qualified laboratories (tensile strength) Sample Number of Mean tensile strength laboratories Reproducibility standard deviation Coe fficient o f sR CV, R variation Reproducibility limit R N/m N/m % N/m A 11 121 11 9,1 30 B 10 643 30 4,7 84 A.3 Stretch at maximum force Table A.3 — Repeatability results o f an interlaboratory test by qualified laboratories (stretch at maximum force) Sample Number of laboratories Mean stretch at maximum force % Repeatability standard deviation Coe fficient o f variation Repeatability limit sr CV, r r % % % A 10 16,8 1,7 9,9 4,6 B 10 15,5 0,76 4,9 2,1 Table A.4 — Reproducibility results o f an interlaboratory test by qualified laboratories (stretch at maximum force) Sample Number of laboratories Mean stretch at maximum force % Reproducibility standard deviation Coe fficient o f variation Reproducibility limit sR CV, R R % % % A 10 16,8 1,9 11 5,1 B 10 15,5 1,3 8,1 3,5 I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n ISO 62 -4: 01 6(E) Bibliography [1] [2] [3] [4] [5] [6] [7] [8] ISO 287, Paper and board — Determination of moisture content of a lot — Oven-drying method ISO 638, Paper, board and pulps — Determination of dry matter content — Oven-drying method ISO 5725-1, Accuracy (trueness and precision) of measurement methods and results — Part 1: General principles and definitions ISO 12625-1, Tissue paper and tissue products — Part 1: General guidance on terms ISO 12625-6, Tissue paper and tissue products — Part 6: Determination of grammage ISO 15755, Paper and board — Estimation of contraries ISO/TR 24498, Paper, board and pulps — Estimation of uncertainty for test methods TAPPI T 1200 sp-07, Interlaboratory Evaluation of Test Methods to Determine TAPPI Repeatability and Reproducibility © ISO 2016 – All rights reserved I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n ISO 62 -4: 01 6(E) I C S 85 060 Price based on pages © ISO 2016 – All rights reserved I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n