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1、DRAFT FOR DEVELOPMENT DD CEN/TS 14689:2006 Leather Physical and mechanical tests Determination of bagginess, creep and relaxation ICS 59.140.30 ? Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:27:50 GMT+00:00 2006, Uncontrolled Copy, (c) BSI DD CEN/TS 14689:
2、2006 This Draft for Development was published under the authority of the Standards Policy and Strategy Committee on 31 July 2006 BSI 2006 ISBN 0 580 48904 3 National foreword This Draft for Development is the official English language version of CEN/TS 14689:2006. This publication is not to be regar
3、ded as a British Standard. It is being issued in the Draft for Development series of publications and 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 expe
4、rience of its practical application 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 responsible for its conversion to a European standard. A review of this publication will be initiated 2 ye
5、ars 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 announcement in the appropriate issue of Update Standards. According to the replies received by the en
6、d of the review period, the responsible BSI Committee 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
7、and coated fabrics, at British Standards House, 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
8、. Cross-references The British Standards which implement 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
9、or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Summary of pages This document comprises a front cover, an inside front cover, the CEN/TS title page, pages 2 to 8, an inside ba
10、ck cover 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. DateComments Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:27:50 GMT+00:00 2006, Uncontr
11、olled Copy, (c) BSI TECHNICAL SPECIFICATION SPCIFICATION TECHNIQUE TECHNISCHE SPEZIFIKATION CEN/TS 14689 May 2006 ICS 59.140.30 English Version Leather - Physical and mechanical tests - Determination of bagginess, creep and relaxation Cuir - Essais physiques et mcaniques - Dtermination du pochage, d
12、u fluage et de la relaxation Leder - Physikalische und mechanische Prfungen - Bestimmung von Ausbeulneigung, Kriechen und Relaxation This 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 t
13、hree years. After two years the members of CEN will be requested to submit their comments, particularly on the question 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
14、available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards 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 Aust
15、ria, 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 United Kingdom. EUROPEAN COMMITTEE FOR
16、STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2006 CENAll rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. CEN/TS 14689:2006: E Licensed Copy: London South
17、Bank University, London South Bank University, Tue Dec 12 05:27:50 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 2 Contents Page Foreword3 1 Scope4 2 Normative references4 3 Principle4 4 Apparatus.5 5 Sampling and sample preparation.6 6 Procedure.6 7 Expression of Results.6 8 Test report7 Annex A (info
18、rmative) Sources of apparatus .8 CEN/TS 14689:2006 Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:27:50 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 3 Foreword This Technical Specification (CEN/TS 14689:2006) has been prepared by Technical Committee CEN/TC “28
19、9”, the secretariat of which is held by UNI. Attention is drawn to the possibility that some of 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 Reg
20、ulations, the national standards organizations of the following countries are bound to announce this Technical Specification: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherla
21、nds, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. CEN/TS 14689:2006 Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:27:50 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 4 1 Scope This Technical Specific
22、ation 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 and apparel leather. Leather is a viscoelastic material and, upon r
23、emoval 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 leather. Due to the nature of the test method described below it is al
24、so 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 this property in leather. 2 Normative references The following refe
25、renced 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 ISO 2418, Leather - Chemical, physical and mechanical and fastne
26、ss 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 machines - Part 1: Tension/compression testing machines - Verification a
27、nd 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 required to obtain the load for a specific time and is then retrac
28、ted. 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 index and stress relaxation index can also be determined using thi
29、s 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 14689:2006 Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:27:50 GMT+00:00 200
30、6, Uncontrolled Copy, (c) BSI 5 Key: 1 Probe 2 Force (applied to centre of 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
31、an accuracy of at least 2% as specified by Class 2 of EN 7500-1; a uniform 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 w
32、ith a hemispherical test head of diameter 9 mm 0,1 mm and a radius of curvature 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
33、 the tensile testing machine (4.1). 4.4 Clamping device, to clamp a circular 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 a
34、llow unrestricted extension of the leather sample. CEN/TS 14689:2006 Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:27:50 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 6 5 Sampling and sample preparation 5.1 Sample in accordance with EN ISO 2418. Cut three test
35、 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 tested in one batch, then only one sample need be taken from each hide or skin, provide
36、d 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 EN ISO 2419. 6.2 Secure the probe (4.2) in the motional cross head of the tensile testi
37、ng 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 simulating wear to clothing etc. For upholstery leather the load should be applied to the gr
38、ain 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 the leather resulting in a force of 0,25 N 0,01 N. 6.5 The probe shall move from the ze
39、ro 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 held in position for 10 s 0,5 s, and then return to the zero position at a speed of 60
40、0mm/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 returned to the zero position and held for a final relaxation time of 60 s 0,5 s. 6.9 After t
41、he 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 (residual distension) in millimetres shall be taken as the bagginess result for the leather sa
42、mple. 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 14689:2006 Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:27:50 GMT+00:00 2006, Uncontrolled Co
43、py, (c) BSI 7 7.2 Creep index From a graph of displacement 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).
44、The gradient of this graph is defined as the creep index. 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
45、cycle. Plot a graph of force (y-axis) versus the natural 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
46、 bagginess in mm (7.1); c) mean value for creep index, 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 %
47、rh, or 23C/50 % rh); g) any deviations from the method specified in this h) full details for identification of the sample and any deviations from EN ISO 2418 with respect to sampling. CEN/TS 14689:2006 Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:27:50 GMT
48、+00:00 2006, Uncontrolled Copy, (c) BSI 8 Annex A (informative) Sources of apparatus Examples of suitable products available commercially are given below. This information is given for the convenience of users of this European Standard and does not constitute an endorsement by CEN of these products.
49、 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 14689:2006 Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:27:50 GMT+00:00 2006, Uncontrolled Copy, (c) BSI blank Licensed Copy: London South Bank University, London South Bank University, Tue Dec 12 05:27:50 GMT+00:00 2006, Uncontrolled Copy, (c) BSI DD CEN/TS 146