1、BS EN ISO8067:2008ICS 83.100NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDFlexible cellularpolmeric materials -Determination of tearstrengthLicensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 15/10/2009 03:00, Uncontrolled Copy, (c) BSIThis British Standard
2、was published under theauthority of the StandardsPolicy and StrategyCommittee on 30 June2009. BSI 2009ISBN 978 0 580 56849 7Amendments/corrigenda issued since publicationDate CommentsBS EN ISO 8067:2008National forewordThis British Standard is the UK implementation of EN ISO 8067:2008. Itsupersedes
3、BS EN ISO 8067:1995 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee PRI/24, Testing of rigid and flexible cellular materials.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purpo
4、rt to include all the necessary provisionsof a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunityfrom legal obligations.Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 15/10/2009 03:00, Uncontrolled Copy, (c) BSIEUROPEAN STAND
5、ARDNORME EUROPENNEEUROPISCHE NORMEN ISO 8067December 2008ICS 83.100 Supersedes EN ISO 8067:1995 English VersionFlexible cellular polymeric materials - Determination of tearstrength (ISO 8067:2008)Matriaux polymres alvolaires souples - Dterminationde la rsistance au dchirement (ISO 8067:2008)Flexible
6、 Polymer-Schaumstoffe - Bestimmung desWeiterreiwiderstands (ISO 8067:2008)This European Standard was approved by CEN on 15 November 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national
7、standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any oth
8、er language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, F
9、inland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOM
10、ITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 8067:2008: ELicensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 15/10/2009 03:00, Uncontrolled Copy, (c
11、) BSIINTERNATIONAL STANDARD ISO 8067:2008(E) ISO 2008 All rights reserved 1Flexible cellular polymeric materials Determination of tear strength WARNING Persons using this International Standard should be familiar with normal laboratory practice. This standard does not purport to address all of the s
12、afety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditions. 1 Scope This International Standard specifies two methods for the determination of the tear str
13、ength of flexible cellular polymeric materials: method A, using a trouser test piece; method B, using an angle test piece without a nick. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited app
14、lies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 1923, Cellular plastics and rubbers Determination of linear dimensions ISO 7500-1, Metallic materials Verification of static uniaxial testing machines Part 1: Tension/compression testi
15、ng machines Verification and calibration of the force-measuring system 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 tear strength R maximum force per unit thickness observed when stretching a test piece to rupture 4 Apparatus The tear stre
16、ngth shall be measured on a tensile-testing machine which will indicate the force at which rupture of the test piece takes place. An automatic machine should preferably be used which draws the actual curve, or a stylus or scale should be used having an indicator that remains at the point of maximum
17、force after rupture of the test piece. The accuracy of the test machine shall be class 2 or better as defined in ISO 7500-1. BS EN ISO 8067:2008 Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 15/10/2009 03:00, Uncontrolled Copy, (c) BSI2 ISO 2008 All rights reserved5 Test pieces 5.1 General
18、The test pieces shall be free of skin, voids and flow lines. If the material exhibits a predominant direction of cellular structure (orientation of the cells), the trouser test piece shall be taken in such a way that the plane of the cut subsequently made in the test piece (see Figure 1) is parallel
19、 to, and the long dimension of the cut perpendicular to, the predominant foam-rise direction and the angle test piece shall be taken in such a way that the plane of the V-shaped side of the test piece (see Figure 3) is parallel to, and the long dimension of the test piece perpendicular to, the predo
20、minant foam-rise direction. If this is not possible, the orientation of the long dimension of the cut or the V-shaped side of the test piece with respect to the predominant foam-rise direction shall be stated in the test report. 5.2 Trouser test piece for method A The trouser test piece shall be a r
21、ectangular parallelepiped cut from a sheet of material with a band knife or a cutting die. Each test piece shall have the dimensions given in Figure 1 and a 45 mm to 55 mm cut shall be made at one end. The required tear length (25 mm) shall be marked on the test piece. The predominant foam-rise dire
22、ction for the trouser test piece is indicated by an arrow in Figure 1. Dimensions in millimetres Key 1 location of thickness measurement 2 mark indicating required tear length 3 cut made in test piece aPredominant foam-rise direction. Figure 1 Trouser test piece BS EN ISO 8067:2008 EN ISO 8067:2008
23、(E)Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 15/10/2009 03:00, Uncontrolled Copy, (c) BSI ISO 2008 All rights reserved 35.3 Angle test piece for method B The test piece shall be cut from a sheet of material of thickness 10 mm to 15 mm with a die having the dimensions and shape shown in
24、Figure 2. The predominant foam-rise direction for the angle test piece is indicated in Figure 3. Dimensions in millimetres Key 1 location of thickness measurement of test piece cut out using die Figure 2 Angle test piece die Key 1 sheet of material 2 V-shaped side of test piece aPredominant foam-ris
25、e direction. Figure 3 Predominant foam-rise direction for angle test piece BS EN ISO 8067:2008 EN ISO 8067:2008 (E)Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 15/10/2009 03:00, Uncontrolled Copy, (c) BSI4 ISO 2008 All rights reserved6 Number of test pieces Three test pieces shall be teste
26、d. Additional test pieces may be required if the spread of results is too great (see Clause 9) or to compensate for deviation in the progress of the tear (see 8.2). 7 Conditioning Materials shall not be tested less than 72 h after manufacture, unless it can be demonstrated that the mean results obta
27、ined at either 16 h or 48 h after manufacture do not differ by more than 10 % from those obtained after 72 h, in which case testing is permitted at either 16 h or 48 h, respectively. Prior to the test, the test pieces or the material from which the test pieces are to be cut shall be conditioned for
28、at least 16 h in one of the following atmospheres, unless otherwise specified: (23 2) C, (50 5) % relative humidity; (27 2) C, (65 5) % relative humidity. This conditioning period may form the final part of or, in the case of testing 16 h after manufacture, the whole of the period following manufact
29、ure. In the case of quality-control tests, test pieces may be taken a shorter time (down to a minimum of 12 h) after manufacture and testing carried out after conditioning for a shorter period (down to a minimum of 6 h) in one of the atmospheres specified above. It is recommended that, for referee p
30、urposes, the test is performed 7 days or more after the cellular material has been manufactured. 8 Procedure 8.1 General After conditioning as specified in Clause 7, measure, in accordance with ISO 1923, the thickness of the test piece at the location shown in Figure 1 or Figure 2. 8.2 Method A 8.2.
31、1 Clamp the test piece in the jaws of the test machine, taking care that the jaws grip the test piece properly. Spread the ends of the test piece so that the force is applied in the direction shown in Figure 4. Start the test machine with a jaw speed of 50 mm/min to 500 mm/min. BS EN ISO 8067:2008 E
32、N ISO 8067:2008 (E)Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 15/10/2009 03:00, Uncontrolled Copy, (c) BSI ISO 2008 All rights reserved 5Key 1 held in fixed clamp 2 held in moving clamp aDirection of applied force. Figure 4 Schematic test arrangement 8.2.2 Where necessary in order to kee
33、p the cut in the centre of the test piece while tearing, aid it with light application of a sharp blade, for example a single-edged razor blade. Cutting should be the exception and should be avoided because it could influence the result. Care should be taken when using blades. 8.2.3 When the tear ha
34、s travelled (25 5) mm along the test piece, record the maximum force on the dial or scale. If rupture occurs before a length of 20 mm is torn, reject the test piece and take a fresh one. 8.2.4 For referee purposes, a jaw speed of (50 5) mm/min shall be used. 8.3 Method B 8.3.1 Clamp the test piece i
35、n the jaws of the test machine, taking care to adjust it so that it is symmetrical, in order that the tension will be distributed uniformly over the cross-section. 8.3.2 Start the test machine with a jaw speed of 50 mm/min to 500 mm/min and record the maximum force. 8.3.3 For referee purposes, a jaw
36、 speed of (500 50) mm/min shall be used. BS EN ISO 8067:2008 EN ISO 8067:2008 (E)Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 15/10/2009 03:00, Uncontrolled Copy, (c) BSI6 ISO 2008 All rights reserved9 Expression of results The tear strength R, expressed in newtons per centimetre (N/cm), i
37、s given by the following equation: 10FRd= where F is the maximum force, in newtons (N), registered on the test machine; d is the original thickness, in millimetres (mm), of the test piece. Report the result as the median of the tear strength values calculated for the three test pieces. If one or mor
38、e values deviates by more than 20 % from the median, test two additional test pieces and report the median of all five values. 10 Test report The test report shall include the following information: a) a reference to this International Standard; b) a description of the material tested and the type o
39、f test piece used; c) the conditioning used; d) the jaw speed used; e) the location of the plane of the cut with respect to the predominant rise direction of the cellular structure; f) any deviation of the progress of the tear (causing extra test pieces to be tested); g) the median value of the tear
40、 strength; h) the date of testing. BS EN ISO 8067:2008 EN ISO 8067:2008 (E)Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 15/10/2009 03:00, Uncontrolled Copy, (c) BSI ISO 2008 All rights reserved 7Annex A (informative) Precision comparison for the two types of test piece A.1 Comparative tria
41、l Two types of test piece (the trouser type and the angle type without a nick) were used in the comparative trial. Two types of flexible polyurethane foam were used: sample A: 22 kg/m3general-purpose polyether; sample B: 32 kg/m3high-hardness polyether. All the test pieces of a given type of foam we
42、re taken from the same test sample using a band knife and die-cutting. Testing was carried out in three laboratories in Japan on two days in different weeks. The conditioning and test methods were in accordance with this International Standard. A.2 Test results and precision data for each type of te
43、st piece A.2.1 General The test results and the precision data for the two types of test piece are shown in Tables A.1 and A.2. The precision data in Table A.2 were calculated in accordance with ISO/TR 9272, Rubber and rubber products Determination of precision for test method standards. The precisi
44、on results given in Table A.2 should not be used for the acceptance or rejection of any group of materials without documentation that the results of this precision evaluation are actually applicable to the particular group of materials tested. A.2.2 Repeatability The repeatability, or local domain p
45、recision, for each type of test piece is given, for each repeatability parameter, by the values in Table A.2. Two test results obtained in the same laboratory (by the proper use of this International Standard) that differ by more than the tabulated values for r, in measurement units, and (r), in per
46、cent, should be considered as suspect, i.e. to have come from different populations, and should suggest that some appropriate investigative action be taken. A.2.3 Reproducibility The reproducibility, or global domain precision, for each type of test piece is given, for each reproducibility parameter
47、, by the values in Table A.2. Two test results obtained in different laboratories (by the proper use of this International Standard) that differ by more than the tabulated values for R, in measurement units, and (R), in percent, should be considered as suspect, i.e. to have come from different popul
48、ations, and should suggest that some appropriate investigative action be taken. BS EN ISO 8067:2008 EN ISO 8067:2008 (E)Licensed Copy: Wang Bin, ISO/EXCHANGE CHINA STANDARDS, 15/10/2009 03:00, Uncontrolled Copy, (c) BSI8 ISO 2008 All rights reservedTable A.1 Test results All tear strength values in
49、N/cm Sample A Sample B Method AaMethod BbMethod AaMethod BbTest lab Day 1 Day 2 Day 1 Day 2 Day 1 Day 2 Day 1 Day 2 1 4,7 4,9 6,9 6,6 4,8 3,8 6,9 6,2 2 5,0 4,3 6,8 6,7 4,3 3,2 6,2 6,7 3 5,1 4,8 6,5 6,6 4,2 3,9 6,4 6,7 Mean 4,9 4,7 6,7 6,6 4,4 3,6 6,5 6,5 NOTE Test speed = 500 mm/min. aTrouser test piece. bAngle test piece without nick. Table A.2 Precision data Within laboratory Between laboratory Sample (density) Test method Mean value N/cm srr (r) sRR (R) Method Aa4,80 0,325 0,91 19,0 0,275
