1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 3387:2012Rubber Determinationof crystallization effects byhardness measurementsBS ISO 3387:2012 BRITISH STANDARDNational forewordThis British Standard is the UK implementa
2、tion of ISO 3387:2012. Itsupersedes BS 903-A63:1995 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee PRI/22, Physical testing of rubber.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does
3、 not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2012. Published by BSI StandardsLimited 2012ISBN 978 0 580 69685 5ICS 83.060Compliance with a British Standard cannot confer immunity fromlegal oblig
4、ations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 July 2012.Amendments issued since publicationDate T e x t a f f e c t e dBS ISO 3387:2012 ISO 2012Rubber Determination of crystallization effects by hardness measurementsCaoutchouc Dter
5、mination des effets de la cristallisation au moyen de mesurages de duretINTERNATIONAL STANDARDISO3387Third edition2012-07-01Reference numberISO 3387:2012(E)BS ISO 3387:2012ISO 3387:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All rights reserved. Unless otherwise specif
6、ied, 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 ISOs member body in the country of the requester.ISO copyright officeCase
7、postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 3387:2012ISO 3387:2012(E) ISO 2012 All rights reserved iiiContents PageForeword iv1 Scope 12 Normative references . 13 Principle . 14 Apparatus 15 Test pieces 2
8、5.1 Dimensions . 25.2 Preparation 25.3 Conditioning . 26 Temperature and duration of test 36.1 Temperature 36.2 Duration . 37 Procedure 47.1 Hardness measurement . 47.2 Original hardness 47.3 Initial hardness at test temperature . 47.4 Hardness increase due to crystallization . 48 Expression of resu
9、lts . 49 Test report . 6Annex A (normative) Calibration schedule 8Bibliography .10BS ISO 3387:2012ISO 3387:2012(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards
10、 is normally carried out through ISO technical committees. Each member body interested 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 p
11、art in the work. ISO collaborates closely with the International Electrotechnical Commission (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 p
12、repare International Standards. Draft International Standards adopted by the technical 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
13、 some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 3387 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee SC 2, Testing and analysis.This third edition c
14、ancels and replaces the second edition (ISO 3387:1994), which has been technically revised. A calibration schedule has been added in Annex A and the normative references updated. It also incorporates the Technical Corrigendum ISO 3387:1994/Cor 1:2000.iv ISO 2012 All rights reservedBS ISO 3387:2012IN
15、TERNATIONAL STANDARD ISO 3387:2012(E)Rubber Determination of crystallization effects by hardness measurements1 ScopeThis International Standard specifies a test based on hardness measurements for determining the progressive stiffening of rubber with time, caused by crystallization. It is limited to
16、materials having an initial hardness at a test temperature of from 10 IRHD to 85 IRHD.The method is applicable to raw, unvulcanized (compounded) and vulcanized rubber. It is mainly of interest for rubber with a marked crystallization tendency at temperatures experienced in cold climates, such as chl
17、oroprene and natural rubber.The method is not applicable to fast-crystallizing materials which crystallize to a considerable degree within the time-span of 15 min used for conditioning at test temperature.2 Normative referencesThe following referenced documents are indispensable for the application
18、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.ISO 48:2010, Rubber, vulcanized or thermoplastic Determination of hardness (hardness between 10 IRHD and 100 IRHD)ISO 18899
19、:2004, Rubber Guide to the calibration of test equipmentISO 23529, Rubber General procedures for preparing and conditioning test pieces for physical test methods3 PrincipleOne or the other of the following measurements is made on a test piece stored at the desired temperature:a) the increase in hard
20、ness after a specified storage time;b) the time required for a specified increase in hardness to occur.4 Apparatus4.1 Cold chamber, in accordance with ISO 23529, capable of being maintained within 2 C of the specified temperature and using a gaseous heat-transfer medium.As all final handling and mea
21、surements are to be made within the cold chamber, it shall be possible to perform these operations while the test piece temperature remains within the permissible variations. This can be done by providing suitable equipment which permits manipulation of materials within the chamber from the outside
22、(for example, by means of handholes and gloves through the door or wall of the cabinet).4.2 Hardness gauges, in accordance with ISO 48. Lubricants, if used, shall be of a type not causing friction in the instrument at test temperature.4.3 Tweezers or tongs, for handling the test pieces.4.4 Gloves, f
23、or handling the test equipment. ISO 2012 All rights reserved 1BS ISO 3387:2012ISO 3387:2012(E)4.5 Heated press, for the preparation of raw and unvulcanized (compounded) test pieces.5 Test pieces5.1 DimensionsTests may be carried out on test pieces of different thicknesses. These do not necessarily g
24、ive the same values of hardness readings. Tests intended to be comparable shall be made on test pieces of the same thickness.The upper and lower surfaces of the test piece shall be flat, smooth and parallel to one another. The standard test piece shall be 8 mm to 10 mm thick. Non-standard test piece
25、s may be either thicker or thinner, but in no case shall the test piece be thinner than 4 mm for hardnesses between 35 IRHD and 85 IRHD, or thinner than 6 mm for hardnesses between 10 IRHD and 35 IRHD. The lateral dimensions of both standard and non-standard test pieces shall be such that no test is
26、 made at a distance from the edge of the test piece less than the appropriate distance shown in Table 1.Table 1 Dimensions of test piecesDimensions in millimetresTotal thickness of test pieceMinimum distance from point of contact to edge of test piece4 7,06 8,08 9,010 10,015 11,525 13,05.2 Preparati
27、on5.2.1 Vulcanized rubberTest pieces of vulcanized rubber shall be prepared in accordance with ISO 23529. To obtain the necessary thickness, it is permissible to superimpose two pieces of rubber (but no more than two), provided that these have flat, parallel surfaces.5.2.2 Raw and unvulcanized rubbe
28、rTest pieces of raw and of unvulcanized (compounded) rubber shall be prepared by placing a suitable quantity in a preheated mould and then applying heat and pressure (4.5) for a suitable time. The mould, still under pressure, shall be cooled to standard laboratory temperature (see ISO 23529). After
29、15 min, the pressure shall be released and the test piece removed. It shall be free from blisters and porosity. Values of mould temperature and time of application of pressure required to produce a suitable test piece depend upon the type of rubber. A temperature of 150 C applied for 3 min has been
30、found suitable for many raw rubbers, while a temperature of 120 C applied for 3 min has been found satisfactory for many compounded rubbers. However, for some materials, longer times or higher mould temperatures might be necessary to ensure a smooth and flat test piece surface. Under no circumstance
31、s shall conditions be used that cause incipient cure or degradation.5.3 Conditioning5.3.1 Time-interval between vulcanization and testingWhen appropriate, the time interval between vulcanization and testing shall be in accordance with ISO 23529.2 ISO 2012 All rights reservedBS ISO 3387:2012ISO 3387:
32、2012(E)5.3.2 Decrystallization and conditioningTest pieces of vulcanized rubber or test pieces moulded from raw or unvulcanized (compounded) rubber kept for more than 8 h after moulding before testing shall be decrystallized immediately before testing by heating them in an oven at 70 C for 45 min. T
33、hey shall then be conditioned at the standard laboratory temperature (see ISO 23529) for at least 30 min and no more than 60 min before testing.6 Temperature and duration of test6.1 TemperatureThe test shall be carried out at one of the following temperatures (see ISO 23529):+ 23 C 2 C (standard lab
34、oratory temperature)+ 27 C 2 C (standard laboratory temperature)+ 10 C 2 C0 C 2 C 10 C 2 C 25 C 2 C 40 C 2 C 55 C 2 C 70 C 2 CIf not specified for special reasons, the test shall be carried out at the temperature which is closest to the one where the crystallization rate is at its maximum whenever t
35、his is known.NOTE Generally, crystallization rates are known to have their maxima at the following approximate temperatures:Rubber polymer Temperature of maximum crystallization rate CChloroprene rubber 10Polyurethane rubber 10Natural rubber (1,4-cis-polyisoprene)25Dimethyl silicone rubber 551,4-cis
36、-polybutadiene 556.2 DurationHardness measurements are generally taken after (24050,) h and (16820) h of storage at the test temperature. Intermediate times of reading that enable the hardness to be plotted against time shall be used (48 h and 96 h are suggested). Longer times of storage may be used
37、 if the hardness is still increasing at 168 h.If the hardness increase after (24050,) h is more than 10 IRHD above the reading of initial hardness, the test shall be repeated using shorter times of storage (1 h, 2 h, 4 h and 8 h are suggested). ISO 2012 All rights reserved 3BS ISO 3387:2012ISO 3387:
38、2012(E)7 Procedure7.1 Hardness measurementCarry out the hardness measurement in accordance with ISO 48. The method selected shall be used for the entire test. Make one measurement at either three or five different points distributed over the test piece and take the median of the results. Make each r
39、eading at a point at least 4 mm away from points where any previous readings have been made. The same hardness gauge shall be used throughout any one test, the appropriate gauge being determined from the initial hardness at the test temperature. For initial hardnesses between 10 IRHD and 30 IRHD, th
40、e instrument specified for method L of ISO 48:2010 shall be used, for initial hardnesses between 30 IRHD and 80 IRHD, the instrument specified for method N of ISO 48:2010 shall be used, and for hardnesses over 80 IRHD, the instrument specified for method H of ISO 48:2010 shall be used. If the hardne
41、ss increase gives values above 35 IRHD for method L, the hardness readings shall be determined from an extension to ISO 48:2010, Table 5, calculated using the equation given in ISO 48:2010, Annex A.7.2 Original hardnessFirst measure the hardness with the test piece and test equipment conditioned at
42、the standard laboratory temperature (see ISO 23529). This measurement gives additional information but is not used in the calculation of crystallization effects and may be omitted for highly plastic samples of unvulcanized rubber.7.3 Initial hardness at test temperatureCondition the hardness gauge (
43、4.2) and the tweezers or tongs (4.3) in the cold chamber (4.1) at the desired test temperature for at least 60 min.Place the test piece in the cold chamber at the desired test temperature. After 15 min 1 min, take the first hardness reading, using the tweezers or tongs for handling the test piece an
44、d the gloves (4.4) for handling the test equipment. If the initial hardness reading is above 85 IRHD, the method is not applicable.The hardness gauge (4.2) used in this test procedure is normally conditioned and operated inside the cold chamber. Alternatively, a special device may be used where the
45、body of the hardness gauge is placed outside the cold chamber and connected with the indenter in the cold chamber by means of a rod with low heat-conductive capacity, and constructed to avoid the introduction of additional friction.7.4 Hardness increase due to crystallizationRepeat the hardness meas
46、urements, as specified in 7.1, after the specified times of storage at the test temperature.After all measurements have been completed, it is advisable to dry all apparatus by warming it with circulating air to approximately 40 C.8 Expression of results8.1 For specification purposes, the hardness in
47、crease between the initial hardness reading and the reading taken after (16820) h storage shall be calculated and stated in the test report see Figure 1, graph a). If this hardness increase is greater than 10 IRHD, the readings at different times shall be plotted against time (time on logarithmic sc
48、ale) and a smooth curve fitted to the points. From the curve, the time corresponding to a hardness increase of 10 IRHD shall be obtained by interpolation see Figure 1, graph b).The same procedure is applied, using the shorter time scale, when the hardness increase after (24050,) h exceeds 10 IRHD.Th
49、e increase in hardness after a specified time or the time for a specified increase in hardness may also be used for reporting of data to comply with requirements in certain specifications see Figure 1, graph c).4 ISO 2012 All rights reservedBS ISO 3387:2012ISO 3387:2012(E)8.2 For other purposes, the time taken for half the hardness increase to occur between the initial and final hardness may be given see Figure 1, graph d), using the smooth curve of hardness versus time. This
