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1、 Reference number ISO 2439:2008(E) ISO 2008 INTERNATIONAL STANDARD ISO 2439 Fourth edition 2008-12-15 Flexible cellular polymeric materials Determination of hardness (indentation technique) Matriaux polymres alvolaires souples Dtermination de la duret (technique par indentation) ISO 2439:2008(E) PDF
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5、 PROTECTED DOCUMENT ISO 2008 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or I
6、SOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2008 All rights reserved -,-,- ISO 2439:2008(E) ISO 2008 All rights reserved ii
7、i Contents Page Foreword iv 1 Scope . 1 2 Normative references. 1 3 Terms and definitions. 2 4 Principle. 2 5 Apparatus 2 6 Test pieces 3 6.1 Shape and dimensions. 3 6.2 Samples showing orientation 3 6.3 Conditioning 3 7 Procedure 3 7.1 General. 3 7.2 Preliminary indentation for Methods A, B and C.
8、4 7.3 Method A Determination of the 40 %/30 s indentation hardness index . 4 7.4 Method B Determination of the 25 %-40 %-65 %/30 s indentation hardness characteristics. 4 7.5 Method C Determination of the 40 % indentation hardness check. 5 7.6 Method D Determination of the 25 %/20 s low indentation
9、hardness index 5 7.7 Method E Determination of the compressive deflection coefficient and hysteresis loss rate 5 8 Repeat tests. 7 9 Test report . 7 Annex A (informative) Test method parameters and typical graphs 8 Annex B (informative) Precision of Method E . 12 Bibliography. 14 ISO 2439:2008(E) iv
10、 ISO 2008 All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interes
11、ted in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical C
12、ommission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the tech
13、nical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO
14、shall not be held responsible for identifying any or all such patent rights. ISO 2439 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee SC 4, Products (other than hoses). This fourth edition cancels and replaces the third edition (ISO 2439:1997 and ISO 2439:1997
15、/Cor.1:1998), which has been technically revised. Major modifications in this revised text are: a) change in Scope to cover five methods; b) inclusion of Figure 1 to illustrate the force-indentation curve; and c) inclusion of informative annexes. -,-,- INTERNATIONAL STANDARD ISO 2439:2008(E) ISO 200
16、8 All rights reserved 1 Flexible cellular polymeric materials Determination of hardness (indentation technique) WARNING Persons using this International Standard should be familiar with normal laboratory practice. This International Standard does not purport to address all of the safety problems, if
17、 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 The indentation hardness of flexible cellular materials is a measure of their load-bearing properties. Th
18、is International Standard specifies four methods (A to D) for the determination of indentation hardness and one method (E) for determination of compressive deflection coefficient and hysteresis loss rate of flexible cellular materials. Annex A provides a summary of test parameters and typical force-
19、indentation graphs obtained with these methods. These five methods are applicable only to latex foam, urethane foam and PVC foam of the open-cell type. The methods specified can be used for testing finished articles and for the characterization of bulk material. This International Standard specifies
20、 the following methods: a) Method A Determination of the 40 %/30 s indentation hardness index, which gives a single indentation measurement for laboratory test purposes; b) Method B Determination of the 25 %-40 %-65 %/30 s indentation hardness characteristics, which provides information about the sh
21、ape of the hardness indentation curve; c) Method C Determination of the 40 % indentation hardness check, which is a quick procedure suitable for quality control testing; d) Method D Determination of the 25 %/20 s low indentation hardness index, which is a quick procedure suitable as an inspection te
22、st; e) Method E Determination of the compressive deflection coefficient and hysteresis loss rate, which gives additional information about the load-bearing properties of materials. The results obtained by these methods relate only to the test conditions specified and cannot, in general, be used dire
23、ctly for design purposes. 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.
24、ISO 1382, Rubber Vocabulary ISO 2439:2008(E) 2 ISO 2008 All rights reserved ISO 7500-1, Metallic materials Verification of static uniaxial testing machines Part 1: Tension/compression testing machines Verification and calibration of the force-measuring system ISO 23529, Rubber General procedures for
25、 preparing and conditioning test pieces for physical test methods 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 1382 and the following apply. 3.1 indentation hardness total force required to produce, under specified conditions, a specified indentat
26、ion of a standard test piece NOTE Indentation hardness is expressed in newtons. 3.2 compressive deflection coefficient Sf ratio of the 65 % indentation force deflection to the 25 % indentation force deflection 3.3 hysteresis loss rate Af energy difference between the loading and unloading of a test
27、piece under cyclic deformation NOTE Hysteresis loss rate is expressed as a percentage of the loading energy. 4 Principle The forces required to produce specified indentations under specified conditions are measured. 5 Apparatus 5.1 Test machine. The test machine shall be capable of indenting the tes
28、t piece between a supporting surface (5.2) and an indentor (5.3) having a uniform relative motion, in the vertical direction, of (100 20) mm/min. The test machine shall have means of measuring force in conformance with Class 1 of ISO 7500-1 or of measuring with a precision of 1 N, and of measuring t
29、he test piece thickness under load with a precision of 0,25 mm. The test machine for Method C and Method E shall have its force gauge fitted with a tell-tale needle and/or shall be equipped to make autographic load-indentation plots. The test machine shall also be capable of maintaining the specifie
30、d degree of indentation with a precision of 0,25 mm for the specified period. 5.2 Supporting surface. Unless otherwise specified, the test pieces shall be supported on a smooth, flat, horizontal and rigid surface larger than the test piece and suitably vented with holes approximately 6 mm in diamete
31、r and of approximately 20 mm pitch, to allow the escape of air from below the test piece. -,-,- ISO 2439:2008(E) ISO 2008 All rights reserved 3 5.3 Indentor. The indentor shall be mounted preferably by a ball joint free from vertical movement, although other methods of mounting are permitted. The in
32、dentor shall be flat and circular, with a diameter of 3 0 200+ mm and a 0,5 0 1,0+ mm radius at the lower edge. The lower surface shall be smooth but not polished. 6 Test pieces 6.1 Shape and dimensions Material shall be cut to obtain a standard-size square of length of side 20 0 380+ mm, with a thi
33、ckness of (50 2) mm. Sheets of less than this standard thickness shall be plied together to approximate as closely as possible to the standard thickness. Finished articles may be tested as agreed between purchaser and supplier. NOTE Results on plied material and on finished articles may not be the s
34、ame as would be obtained with the standard test piece. 6.2 Samples showing orientation If samples show orientation of the cellular structure, the direction in which the indentation is to be carried out shall be agreed between the interested parties. Normally, testing should be carried out in that di
35、rection in which the finished product will be stressed under service conditions. 6.3 Conditioning Material shall not be tested sooner than 72 h after manufacture, unless at either 16 h or 48 h after manufacture it can be demonstrated that the mean result does not differ by more than 10 % from that o
36、btained after 72 h. Testing is permitted at either 16 h or 48 h if, at the specified time, the above criterion has been satisfied. Prior to the test, the test pieces shall be conditioned, undeflected and undistorted, for at least 16 h in one of the following atmospheres, as given in ISO 23529. (23 2
37、) C, (50 5) % relative humidity; (27 2) C, (65 5) % relative humidity. This conditioning period can form the latter part of the period following manufacture. In case of quality control tests, test pieces may be sampled at 12 h after manufacture or later, and testing is permitted after conditioning f
38、or at least 6 h in one of the specified atmospheres. 7 Procedure 7.1 General Carry out the test immediately after conditioning, preferably under the same atmospheric conditions as specified in 6.3. NOTE See Annex A for assistance in understanding each test method. ISO 2439:2008(E) 4 ISO 2008 All rig
39、hts reserved Position the test piece on the supporting surface so that the centre of the test piece, or other agreed test area, is located below the centre of the indentor. Test pieces having cavities on one side shall be placed with the cavity side next to the supporting surface. If a test piece ha
40、s cavities, the acceptable characteristics of the cavities, such as quantity, dimensions and location in the test piece, should be agreed between purchaser and supplier. 7.2 Preliminary indentation for Methods A, B and C a) Apply a force of 0 2 5 N to the selected test area and measure the thickness
41、 of the test piece. This value is the point of zero indentation. b) Indent the test piece at an indentor rate of (100 20) mm/min, to produce an indentation of (70 2,5) % of the thickness. After reaching this deflection, release the load at the same rate. c) Repeat this loading and unloading twice mo
42、re, then proceed with 7.3, 7.4 or 7.5 as appropriate. 7.3 Method A Determination of the 40 %/30 s indentation hardness index Immediately after the third unloading see 7.2 c), indent the test piece by (40 1) % of its thickness. Maintain this deflection for a period of (30 1) s, note the corresponding
43、 force, in newtons, and release the force. Only the result of a test conducted by Method A, on a standard-size test piece without plying, shall be known as the indentation hardness index. 7.4 Method B Determination of the 25 %-40 %-65 %/30 s indentation hardness characteristics Immediately after the
44、 third unloading see 7.2 c), carry out the following operations: a) indent the test piece by (25 1) % of the thickness; b) maintain this indentation for a period of (30 1) s; c) measure the force required; d) increase the indentation to (40 1) % of the thickness; e) maintain this indentation for a p
45、eriod of (30 1) s; f) measure the force required; g) increase the indentation to (65 1) % of the thickness; h) maintain this indentation for a period of (30 1) s; i) measure the force required. The results of a test conducted by Method B on a standard test piece shall be known as the standard indent
46、ation hardness characteristics of that material. If a product is tested, the results shall be known as the product indentation hardness characteristics. NOTE Convenient means of expressing the results obtained by Method B are indentation factors, which are the ratios of the forces required to obtain
47、 the indentations of 25 % and 65 % to the force required to obtain the indentation of 40 %. ISO 2439:2008(E) ISO 2008 All rights reserved 5 7.5 Method C Determination of the 40 % indentation hardness check Immediately after the third unloading see 7.2 c), carry out the following operations: a) start
48、 the autographic recording, or bring back the tell-tale needle of the force gauge, and indent the test piece to (40 1) % of its thickness; b) record the force, in newtons, using the tell-tale needle or the instantaneous maximum of the autographic recorder; c) release the force. The results of a test
49、 conducted by Method C shall be known as the indentation hardness check. NOTE This is a faster, quality-control test for indentation hardness. The variability of results obtained in this way is usually higher. It should also be noted that the results obtained in this way may be related to results obtained with Method A