1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58bagginess, creep and relaxationICS 59.140.30Leather Physical and mechanical tests Determination of
2、DRAFT FOR DEVELOPMENTDD CEN/TS 14689:2006DD CEN/TS 14689:2006This Draft for Development was published under the authority of the Standards Policy and Strategy Committee on 31 July 2006 BSI 2006ISBN 0 580 48904 3According to the replies received by the end of the review period, the responsible BSI Co
3、mmittee will decide whether to support the conversion into a European standard, to extend the life of the Technical Specification or to withdraw it. Comments should be sent in writing to the Secretary of BSI Technical Committee TCI/69, Footwear, leather and coated fabrics, at British Standards House
4、, 389 Chiswick High Road, London W4 4AL, giving the document reference and clause number and proposing, where possible, an appropriate revision of the text.A list of organizations represented on this committee can be obtained on request to its secretary.Cross-referencesThe British Standards which im
5、plement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication d
6、oes not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Summary of pagesThis document comprises a front cover, an inside front cover, the CEN/TS title page, pages 2 to 8, an inside back cover and a back cover.The BSI copyright notice d
7、isplayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date Commentsapplication may be obtained.Comments arising from the use of this Draft for Development are requested so that UK experience can be reported to the European organization resp
8、onsible for its conversion to a European standard. A review of this publication will be initiated 2 years after its publication by the European organization so that a decision can be taken on its status at the end of its 3-year life. Notification of the start of the review period will be made in an
9、announcement in the appropriate issue of Update Standards.National forewordThis Draft for Development is the official English language version of CEN/TS 14689:2006.This publication is not to be regarded as a British Standard.It is being issued in the Draft for Development series of publications and
10、is of a provisional nature because the new edition of the European document has been issued as a Technical Specification. It should be applied on this provisional basis, so that information and experience of its practical TECHNICAL SPECIFICATIONSPCIFICATION TECHNIQUETECHNISCHE SPEZIFIKATIONCEN/TS 14
11、689May 2006ICS 59.140.30English VersionLeather - Physical and mechanical tests - Determination ofbagginess, creep and relaxationCuir - Essais physiques et mcaniques - Dtermination dupochage, du fluage et de la relaxationLeder - Physikalische und mechanische Prfungen -Bestimmung von Ausbeulneigung, K
12、riechen und RelaxationThis Technical Specification (CEN/TS) was approved by CEN on 13 March 2006 for provisional application.The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit theircomments, particularly on the qu
13、estion whether the CEN/TS can be converted into a European Standard.CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS availablepromptly at national level in an appropriate form. It is permissible to keep conflicting national standar
14、ds in force (in parallel to the CEN/TS)until the final decision about the possible conversion of the CEN/TS into an EN is reached.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, I
15、taly, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050
16、 Brussels 2006 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. CEN/TS 14689:2006: E2 Contents Page Foreword3 1 Scope 4 2 Normative references 4 3 Principle4 4 Apparatus .5 5 Sampling and sample preparation.6 6 Procedure .6 7 Expression
17、of Results .6 8 Test report 7 Annex A (informative) Sources of apparatus .8 CEN/TS 14689:20063 Foreword This Technical Specification (CEN/TS 14689:2006) has been prepared by Technical Committee CEN/TC “289”, the secretariat of which is held by UNI. Attention is drawn to the possibility that some of
18、the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to announce
19、this Technical Specification: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the U
20、nited Kingdom. CEN/TS 14689:20064 1 Scope This Technical Specification specifies a method of determining the bagginess of leather together with its creep and stress relaxation properties. It is applicable to all non-rigid leathers. e.g. shoe upper leather, upholstery leather, leathergoods leather an
21、d apparel leather. Leather is a viscoelastic material and, upon removal of any applied force, only a proportion of the extension observed is recovered. Even some time after removal of the force there is some degree of permanent deformation which is known as the retained set or bagginess of the leath
22、er. Due to the nature of the test method described below it is also possible to obtain a measure of the creep and stress relaxation properties of leather. Although the creep index quoted is not obtained via the true definition of creep, it will however provide a valuable comparative indication of th
23、is property in leather. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN
24、 ISO 2418, Leather - Chemical, physical and mechanical and fastness tests - Sampling location (ISO 2418:2002) EN ISO 2419, Leather - Physical and mechanical tests - Sample preparation and conditioning (ISO 2419:2006) EN ISO 7500-1, Metallic materials - Verification of static uniaxial testing machine
25、s - Part 1: Tension/compression testing machines - Verification and calibration of the force-measuring system (ISO 7500-1:2004) 3 Principle A test piece is secured around its circumference and a probe is applied until a prescribed force is obtained (see Figure 1). The probe is held at the position r
26、equired to obtain the load for a specific time and is then retracted. This is repeated for five cycles after which the test piece is allowed to relax with no force applied. The residual distension of the test piece is recorded to give a measure of the degree of bagginess (or retained set). A creep i
27、ndex and stress relaxation index can also be determined using this method by recording the extension required to reach the prescribed force at each cycle and the rate at which the applied force decays whilst the probe is held in position. CEN/TS 14689:20065 Key: 1 Probe 2 Force (applied to centre of
28、 sample) 3 Leather 4 Sample holder Figure 1 Diagrammatic representation of the test method 4 Apparatus 4.1 Tensile testing machine, with: a force range appropriate to the specimen under test; a means of recording the force to an accuracy of at least 2% as specified by Class 2 of EN 7500-1; a uniform
29、 speed of separation of the jaws of 100 mm/min 20 mm/min; a means of following a programme of compression cycles as detailed in the procedure (6.4 to 6.7). 4.2 Cylindrical probe, comprised of steel or other suitable material with a hemispherical test head of diameter 9 mm 0,1 mm and a radius of curv
30、ature of 20 mm 0,1 mm. The length of the probe should be suitable to allow ease of testing whilst retaining rigidity. e.g. approximately 40 mm. 4.3 A method of securing the probe (4.2), vertically in the motional cross head of the tensile testing machine (4.1). 4.4 Clamping device, to clamp a circul
31、ar test piece around its circumference. A circular area of 35 mm 0,2 mm diameter must be exposed for testing. The clamping device should be positioned centrally beneath the probe. Contact of the probe with the leather should allow unrestricted extension of the leather sample. CEN/TS 14689:20066 5 Sa
32、mpling and sample preparation 5.1 Sample in accordance with EN ISO 2418. Cut three test pieces to a suitable size for the clamping procedure employed (4.4) and to ensure that there is no slippage of the test piece during testing. NOTE If there is a requirement for more than two hides or skins to be
33、tested in one batch, then only one sample need be taken from each hide or skin, provided that the overall total is not less than three test pieces. 5.2 Condition the test piece in accordance with EN ISO 2419. 6 Procedure 6.1 All testing should be carried out in a standard atmosphere as specified in
34、EN ISO 2419. 6.2 Secure the probe (4.2) in the motional cross head of the tensile testing machine (4.1) and place a test piece in the clamping device (4.4). NOTE For the majority of leathers the load should be applied to the flesh side of grain leather or the grain side of suede leathers, thus simul
35、ating wear to clothing etc. For upholstery leather the load should be applied to the grain side of the test piece. 6.3 Ensure the tensile testing machine is set to follow the programme given below (6.4 to 6.6). 6.4 The zero position for this test shall be taken as the point where the probe contacts
36、the leather resulting in a force of 0,25 N 0,01 N. 6.5 The probe shall move from the zero position towards the leather surface at a speed of 100 mm/min 20 mm/min until a force of 75 N 1 N is produced. The probe should then maintain the displacement required to reach this load. 6.6 The probe shall be
37、 held in position for 10 s 0,5 s, and then return to the zero position at a speed of 600mm/min 20 mm/min. 6.7 Immediately the probe returns to the zero position, steps 6.5 to 6.6 shall be carried repeated so a total of 5 times cycles are completed. 6.8 After the 5th cycle, the probe should be return
38、ed to the zero position and held for a final relaxation time of 60 s 0,5 s. 6.9 After the 60 s relaxation time the probe shall move towards the leather surface at a speed of 100 mm/min 20 mm/min until a force of 0,25 N 0,01 N is obtained. 6.10 The distance required to obtain the 0,25 N force (residu
39、al distension) in millimetres shall be taken as the bagginess result for the leather sample. 7 Expression of Results 7.1 Bagginess value The mean residual distension in millimetres taken from three separate test results as determined in 6.10. CEN/TS 14689:20067 7.2 Creep index From a graph of displa
40、cement versus time (obtained during the testing procedure), record the displacement required to obtain a 75 N load for each of the 5 test cycles. Plot a graph of displacement (y-axis) versus the natural logarithm of the test cycle number (x-axis). The gradient of this graph is defined as the creep i
41、ndex. 7.3 Relaxation index From a graph of force versus time (obtained during the testing procedure), record the force exerted by the probe 1, 2, 4, 6 and 8 seconds after application of the initial 75 N load. This should be taken from the 1st test cycle. Plot a graph of force (y-axis) versus the nat
42、ural logarithm of time (x-axis). The gradient of this graph is defined as the stress-relaxation index. 8 Test report The test report shall include the following: a) reference to this Technical Specification; i.e. CEN/TS 14689:2006 b) mean value for bagginess in mm (7.1); c) mean value for creep inde
43、x, if required (7.2); d) mean value for stress-relaxation index, if required (7.3); e) whether the load was applied to the leather grain or flesh; f) the standard atmosphere used for conditioning and testing as given in EN ISO 2419 (i.e. 20 C/65 % rh, or 23C/50 % rh); g) any deviations from the meth
44、od specified in this h) full details for identification of the sample and any deviations from EN ISO 2418 with respect to sampling. CEN/TS 14689:20068 Annex A (informative) Sources of apparatus Examples of suitable products available commercially are given below. This information is given for the co
45、nvenience of users of this European Standard and does not constitute an endorsement by CEN of these products. A suitable apparatus is the Materials Tester manufactured, for example, by: Stable Micro Systems, Vienna Court, Lammas Road, Godalming, Surrey, GU7 1YL, UK. CEN/TS 14689:2006blankDD CEN/TS B
46、SI389 Chiswick High RoadLondonW4 4AL14689:2006BSI British Standards InstitutionBSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter.RevisionsBritish Standar
47、ds are updated by amendment or revision. Users of British Standards should make sure that they possess the latest amendments or editions.It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using th
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