1、March 2008DEUTSCHE NORM English price group 7No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 83.100!$MP“1424596www.din
2、.deDDIN EN ISO 8307Flexible cellular polymeric materials Determination of resilience by ball rebound (ISO 8307:2007)English version of DIN EN ISO 8307:2008-03Weich-elastische polymere Schaumstoffe Bestimmung der Kugel-Rckprallelastizitt (ISO 8307:2007)Englische Fassung DIN EN ISO 8307:2008-03Superse
3、desDIN EN ISO 8307:1998-04www.beuth.deDocument comprises 11 pagesDIN EN ISO 8307:2008-03 2 National foreword This standard has been prepared by Technical Committee ISO/TC 45 “Rubber and rubber products” in collaboration with Technical Committee CEN/TC 249 “Plastics”, (Secretariat: NBN, Belgium). The
4、 responsible German body involved in its preparation was the Normenausschuss Materialprfung (Materials Testing Standards Committee), Technical Committee NA 062-04-37 AA Prfung weich-elastischer Schaumstoffe. The DIN Standard corresponding to the International Standard referred to in clause 2 of the
5、EN is as follows: ISO 23529 DIN ISO 23529 Amendments This standard differs from DIN EN ISO 8307:1998-04 as follows: a) The standard has been editorially revised. b) Figure 1 showing the test apparatus has been updated. Previous editions DIN 53573: 1985-02 DIN EN ISO 8307: 1998-04 National Annex NA (
6、informative) Bibliography DIN ISO 23529, Rubber General procedures for preparing and conditioning test pieces for physical test methods EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 8307 December 2007 ICS 83.100 Supersedes EN ISO 8307:1997English Version Flexible cellular polymeric materi
7、als - Determination of resilience by ball rebound (ISO 8307:2007) Matriaux polymres alvolaires souples - Dtermination de la rsilience par rebondissement dune bille (ISO 8307:2007) Weich-elastische polymere Schaumstoffe - Bestimmung der Kugel-Rckprallelastizitt (ISO 8307:2007) This European Standard
8、was approved by CEN on 24 November 2007. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning suc
9、h national standards 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 other language made by translation under the responsibility of a CEN member into its own languag
10、e and notified to the CEN Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxe
11、mbourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2007 CEN All r
12、ights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 8307:2007: E2 DIN EN ISO 8307:2008-03 EN ISO 8307:2007 (E) Contents Page Foreword . 3 1 Scope . 4 2 Normative references . 4 3 Terms and definitions 4 4 Principle . 4 5 Apparatus 4 5.1 Gen
13、eral . 4 5.2 Apparatus with manual reading 5 5.3 Apparatus with automatic reading 6 6 Test pieces 6 7 Number of test pieces 6 8 Test conditions . 6 9 Procedure 7 9.1 Preflex conditioning . 7 9.2 Test method . 7 10 Expression of results . 7 11 Precision 7 12 Test report . 7 Annex A (informative) Exam
14、ple of electronic measurement procedure 9 Foreword This document (EN ISO 8307:2007) has been prepared by Technical Committee ISO/TC 45 “Rubber and rubber products“ in collaboration with Technical Committee CEN/TC 249 “Plastics” the secretariat of which is held by NBN. This European Standard shall be
15、 given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by June 2008, and conflicting national standards shall be withdrawn at the latest by June 2008. Attention is drawn to the possibility that some of the elements of this document may b
16、e the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN ISO 8307:1997. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to i
17、mplement this European Standard: Austria, Belgium, Bulgaria, 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, Switzerl
18、and and the United Kingdom. Endorsement notice The text of ISO 8307:2007 has been approved by CEN as a EN ISO 8307:2007 without any modification. 3 DIN EN ISO 8307:2008-03 EN ISO 8307:2007 (E) WARNING Persons using this International Standard should be familiar with normal laboratory practice. This
19、standard does not purport to address all of the safety 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
20、a method for determining the resilience by ball rebound of flexible cellular polymeric materials. 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
21、 edition of the referenced document (including any amendments) applies. ISO 23529, Rubber General procedures for preparing and conditioning test pieces for physical test methods 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 open-cell flexib
22、le cellular material flexible cellular material with less than 25 % of its cell volume closed 3.2 closed-cell flexible cellular material flexible cellular material with more than 25 % of its cell volume closed 4 Principle A steel ball is dropped on to a test piece from a specified height and the hei
23、ght of rebound is measured. 5 Apparatus 5.1 General The ball rebound test apparatus (see Figure 1) shall consist of a 30 mm to 65 mm inside diameter vertical transparent tube, into which a 16 mm 0,5 mm diameter steel ball with a mass of 16,8 g 1,5 g is released by a magnet or other suitable device.
24、The steel ball shall be released so that it falls without rotation and is 4 DIN EN ISO 8307:2008-03 EN ISO 8307:2007 (E) effectively centred. The height of the drop shall be 500 mm 0,5 mm. Since it is most convenient to note the position of the top of the ball on rebound, the top of the ball shall b
25、e 516 mm above the surface of the test piece. Thus, “zero” rebound shall be the diameter of the ball above the specimen surface. Measurement errors can arise if the tube is not held in a vertical position, and measurements may be invalid due to contact of the rebounding ball and the inner surface of
26、 the tube. It is therefore important to use a spirit level or similar device to ensure that the tube is mounted at right angles to the rigid baseplate, and that the baseplate itself is horizontal. Dimensions in millimetres Key 1 magnet or other suitable device 2 steel ball 3 transparent tube 4 test
27、piece 5 rigid baseplate Figure 1 Diagrammatic arrangement of test apparatus 5.2 Apparatus with manual reading The scale on the back of the tube shall be graduated directly in per cent as follows: every 5 % (25 mm) a complete circle shall be scribed and at every 1 % a 120 arc shall be scribed on the
28、tube. The complete circles are an essential part of the apparatus, since they are used to eliminate parallax error. 5 EN ISO 8307:2007 (E) DIN EN ISO 8307:2008-03 5.3 Apparatus with automatic reading A device capable of determining the rebound height of the steel ball by electronic means can also be
29、 used, as long as it has been demonstrated to give the same results as the manual-reading apparatus. The rebound height can be calculated from, for example, the rebound velocity or the time interval between the first and second contacts of the ball with the foam surface (see Annex A). The apparatus
30、can be equipped with any such device provided it is capable of determining the rebound height to a precision of 1 % of the total drop height (i.e. 5 mm). For this type of apparatus, the tube does not require graduations. 6 Test pieces 6.1 The test pieces shall have plane, parallel top and bottom sur
31、faces. 6.2 The test pieces shall consist of the entire product sample or a suitable portion of it, except that in no case shall the thickness be less than 50 mm or the area less than 100 mm 100 mm. Test pieces less than 50 mm thick shall be plied up, without the use of cement, to a minimum of 50 mm.
32、 For moulded products, the top skin shall be removed. NOTE The minimum test piece thickness of 50 mm may not be sufficient for very soft materials: if spuriously high results are obtained, a thicker test piece can be used. Very low density materials may also cause problems due to rebound of the test
33、 piece itself. With multiple-ply test pieces, slipping can occur between the plies. This problem can be overcome by using the largest possible area of test piece. 7 Number of test pieces Three test pieces per sample shall be tested. The three test pieces may be obtained by using separate items or di
34、fferent locations on a given item. 8 Test conditions Material shall be tested not less than 72 h after manufacture, unless, at either 16 h or 48 h after manufacture, it can be demonstrated that the mean rebound resilience values obtained do not differ by more than 10 % from those obtained after 72 h
35、. Testing is permitted at either 16 h or 48 h if, at the selected 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 C 2 C, (50 5) % relative
36、 humidity; 27 C 2 C, (65 5) % relative humidity. This period can form the latter part of the period following manufacture. In the case of quality-control tests, test pieces can be taken a shorter time (down to a minimum of 12 h) after manufacture and testing carried out after conditioning for a shor
37、ter period (down to a minimum of 6 h) in one of the atmospheres specified above. 6 DIN EN ISO 8307:2008-03 EN ISO 8307:2007 (E) 9 Procedure 9.1 Preflex conditioning Open-cell material as defined in 3.1 shall be subjected to preflex conditioning before testing. Preflex the test piece by compressing i
38、t twice to 75 % to 80 % of its original thickness at 0,4 mm/s to 6 mm/s, then allow the test piece to recover for a period of 10 min 5 min. NOTE This preflex conditioning is not applicable to closed-cell material as defined in 3.2. 9.2 Test method 9.2.1 Carry out the test immediately after condition
39、ing, preferably in the same atmosphere as was used to condition the test pieces (see Clause 8). 9.2.2 Centre the test piece at the base of the tube (see Clause 5) and adjust the height of the tube so that zero rebound is 16 mm 0,5 mm above the surface of the test piece. Clamp the tube to make light
40、contact with the test pieces without causing visible compression. 9.2.3 Mount the steel ball on the release mechanism, then drop it and note the maximum rebound height to the nearest percentage point. If the ball strikes the tube on the drop or rebound, the value obtained is invalid. This condition
41、is usually due to the tube not being vertical or to irregularities on the test piece surface. In order to minimize parallax error, the eye-level of the observer shall be such that the markings on the tube in the region where the percentage rebound value is read appear as straight lines. Trial drops
42、are necessary in order to establish the correct eye-level. 9.2.4 At least three rebound values in succession within 1 min shall be obtained on each of the three test pieces. 10 Expression of results For each test piece, determine the median of the three rebound height values. If any value deviates b
43、y more than 20 % (one-fifth) of the median value from the median, make two additional drops and determine the median for all five rebound height values. Using the median values obtained for the three test pieces, determine the overall median value as the rebound resilience value of the material. If
44、automated measurement is employed, the results shall also be expressed to the nearest integer. 11 Precision At the present time, precision data are not available for this test method. 12 Test report The test report shall include the following information: a) a reference to this International Standar
45、d; b) a description of the material tested, including whether open-cell or closed-cell as defined in Clause 3; c) the temperature and humidity at which the test piece was conditioned and tested; d) whether or not electronic measurement was used; 7 EN ISO 8307:2007 (E) DIN EN ISO 8307:2008-03 e) the
46、rebound resilience value as the median of the three test piece medians; f) the individual rebound height values of the three (or five) tests per test piece; g) the material lot number or date of manufacture; h) the date of the test. 8 DIN EN ISO 8307:2008-03 EN ISO 8307:2007 (E) Annex A (informative
47、) Example of electronic measurement procedure The basic construction of the apparatus is as shown in Figure 1. In addition, a light barrier for time measurement is mounted at the lower end of the tube. The time measurement starts with the first contact of the steel ball with the test piece surface a
48、nd stops with the second contact. The time interval is given by the equation tot22htg=where ttotis the time between the two contacts, expressed in seconds; h is the ball rebound height, expressed in millimetres; g is the acceleration due to gravity, expressed in millimetres per second squared. Rearranging the equation gives the ball rebound height h: 2tot8gth=The percentage rebound value R can then be calculated from the equation max100hRh=where hmaxis the height of the drop (500 mm). 9 EN ISO 8307:2007 (E) DIN EN ISO 8307:2008-03
