1、BSI Standards Publication BS ISO 815-1:2014 Rubber, vulcanized or thermoplastic Determination of compression set Part 1: At ambient or elevated temperaturesBS ISO 815-1:2014 BRITISH STANDARD National foreword This British Standard is the UK implementation of ISO 815-1:2014. It supersedes BS ISO 815-
2、1:2008 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee PRI/22, Physical testing of rubber. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessar
3、y provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2014. Published by BSI Standards Limited 2014 ISBN 978 0 580 78734 8 ICS 83.060 Compliance with a British Standard cannot confer immunity from legal obligations. This British Standard was
4、 published under the authority of the Standards Policy and Strategy Committee on 31 August 2014. Amendments issued since publication Date Text affectedBS ISO 815-1:2014 ISO 2014 Rubber, vulcanized or thermoplastic Determination of compression set Part 1: At ambient or elevated temperatures Caoutchou
5、c vulcanis ou thermoplastique Dtermination de la dformation rmanente aprs compression Partie 1: tempratures ambiantes ou leves INTERNATIONAL STANDARD ISO 815-1 Second edition 2014-09-01 Reference number ISO 815-1:2014(E)BS ISO 815-1:2014ISO 815-1:2014(E)ii ISO 2014 All rights reserved COPYRIGHT PROT
6、ECTED DOCUMENT ISO 2014 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Per
7、mission can be requested from either ISO at the address below or ISOs 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 SwitzerlandBS ISO 815-1:2014ISO
8、815-1:2014(E) ISO 2014 All rights reserved iii Contents Page Foreword iv 1 Scope . 1 2 Normative references 1 3 Principle 2 4 Apparatus . 2 5 Calibration 3 6 Test pieces . 4 6.1 Dimensions . 4 6.2 Preparation 4 6.3 Number of test pieces . 4 6.4 Time interval between production and testing 4 6.5 Cond
9、itioning 5 7 Test conditions . 5 7.1 Duration of test . 5 7.2 Temperature of test . 5 8 Procedure. 5 8.1 Preparation of compression assembly . 5 8.2 Thickness measurement . 5 8.3 Applying the compression 6 8.4 Starting the test 6 8.5 Terminating the test . 6 8.6 Internal examination . 6 9 Expression
10、 of results 7 10 Precision . 7 11 Test report . 7 Annex A (informative) Precision . 9 Annex B (normative) Calibration schedule 11 Bibliography .13BS ISO 815-1:2014ISO 815-1:2014(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodie
11、s (ISO member bodies). The work of preparing International Standards 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,
12、 governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. The procedures used to develop this document and those intended for its further m
13、aintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
14、Attention is drawn to the possibility that 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. Details of any patent rights identified during the development of the document will be in the Introdu
15、ction and/or on the ISO list of patent declarations received (see www.iso.org/patents). Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement. For an explanation on the meaning of ISO specific terms and expressions related to co
16、nformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information The committee responsible for this document is ISO/TC 45, Rubber and rubber products, Subcommittee SC 2, Testing
17、 and analysis. This second edition cancels and replaces the first edition (ISO 815-1:2008), which has been technically revised, mainly by addition of a calibration schedule (Annex B). ISO 815 consists of the following parts, under the general title Rubber, vulcanized or thermoplastic Determination o
18、f compression set: Part 1: At ambient or elevated temperatures Part 2: At low temperaturesiv ISO 2014 All rights reservedBS ISO 815-1:2014INTERNATIONAL ST ANDARD ISO 815-1:2014(E) Rubber, vulcanized or thermoplastic Determination of compression set Part 1: At ambient or elevated temperatures WARNING
19、 1 Persons using this part of ISO 815 should be familiar with normal laboratory practice. This part of ISO 815 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 ens
20、ure compliance with any national regulatory conditions. WARNING 2 Certain procedures specified in this part of ISO 815 might involve the use or generation of substances, or the generation of waste, that could constitute a local environmental hazard. Reference should be made to appropriate documentat
21、ion on safe handling and disposal after use. 1 Scope This part of ISO 815 specifies methods for the determination of the compression set characteristics of vulcanized and thermoplastic rubbers at ambient (one method) or elevated temperatures (three methods, A, B, and C, depending on the way the test
22、 piece is released at the end of the test). The methods are intended to measure the ability of rubbers of hardness within the range 10 IRHD to 95 IRHD to retain their elastic properties at specified temperatures after prolonged compression at constant strain (normally 25 %) under one of the alternat
23、ive sets of conditions described. For rubber of nominal hardness 80 IRHD and above, a lower compression strain is used: 15 % for a nominal hardness from 80 IRHD to 89 IRHD and 10 % for a nominal hardness from 90 IRHD to 95 IRHD. NOTE 1 When rubber is held under compression, physical or chemical chan
24、ges that prevent the rubber returning to its original dimensions after release of the deforming force can occur. The result is a set, the magnitude of which depends on the time and temperature of compression as well as on the time, temperature, and conditions of recovery. At elevated temperatures, c
25、hemical changes become increasingly more important and lead to a permanent set. NOTE 2 Short-time compression set tests, typically for 24 h, at elevated temperatures are commonly used as a measure of the state of cure, a means of material classification, and a specification to ensure the quality of
26、a compound. Longer tests, typically for 1 000 h, at elevated temperatures take account of the effect of ageing and are often used to predict service performance, including that of sealing materials. Short-time tests at ambient temperature show mainly the effect of physical changes (re-orientation of
27、 the molecular chains and the fillers). 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the
28、referenced document (including any amendments) applies. ISO 188, Rubber, vulcanized or thermoplastic Accelerated ageing and heat resistance tests ISO 18899:2004, Rubber Guide to the calibration of test equipment ISO 23529:2010, Rubber General procedures for preparing and conditioning test pieces for
29、 physical test methods ISO 2014 All rights reserved 1BS ISO 815-1:2014ISO 815-1:2014(E) 3 Principle A test piece of known thickness is compressed at standard laboratory temperature to a defined strain, which is then maintained constant for a specified time at standard laboratory temperature or a fix
30、ed elevated temperature. The compression is released and, after the test piece has been allowed to recover at a standard laboratory temperature or the elevated temperature for a specified time, the thickness of the test piece is again measured. 4 Apparatus 4.1 Compression assembly, consisting of com
31、pression plates, steel spacers, and clamping device. A typical assembly is shown in Figure 1. 4.1.1 Compression plates, comprising a pair of parallel, flat, highly polished chromium-plated steel or highly polished stainless-steel plates, between the faces of which the test piece is compressed. The p
32、lates shall be sufficiently rigid to ensure that, with a test piece under load, no compression plate bends by more than 0,01 mm and of sufficient size to ensure that the whole of the test piece, when compressed between the plates, remains within the area of the plates. NOTE A surface finish no worse
33、 than Ra 0,4 m (see ISO 4287) has been found to be suitable. Such an Ra can be obtained by a grinding or polishing operation. 4.1.2 Steel spacer(s), to provide the required compression. The spacer(s) shall be of such size and shape that contact with the compressed test piece is avoided. The height o
34、f the spacer(s) shall be chosen so that the compression applied to the test piece is (25 2) % for hardnesses below 80 IRHD, (15 2) % for hardnesses between 80 IRHD and 89 IRHD, (10 1) % for hardnesses of 90 IRHD and higher. 4.1.3 Clamping device, a simple screw device (see Figure 1) is adequate. 4.2
35、 Oven, complying with the requirements specified in ISO 188, method A or method B, and capable of maintaining the compression assembly and test pieces at the test temperature within the tolerance specified in 7.2. NOTE Test results obtained with ovens for method A can be different from those obtaine
36、d with ovens for method B. The time to reach a steady-state temperature depends on the type of oven and the overall heat capacity of the compression assembly. To obtain comparable results in the case of an elevated test temperature and a 24 h test duration, it is necessary to reach the steady-state
37、temperature within the specified tolerances in the interior of the test pieces in not more than 3 h. 4.3 Pair of tongs, for handling the test pieces. 4.4 Thickness gauge, with an accuracy of 0,01 mm (see ISO 23529:2010, 7.1), having a flat circular foot of 4,0 mm 0,5 mm in diameter and a flat solid
38、base-plate and exerting a pressure of 22 kPa 5 kPa 2 ISO 2014 All rights reservedBS ISO 815-1:2014ISO 815-1:2014(E) for solid rubber of hardness equal to or greater than 35 IRHD, or a pressure of 10 kPa 2 kPa if the hardness is less than 35 IRHD. NOTE When using a digital gauge, a resolution of 0,00
39、1 mm is needed to obtain the required accuracy. After testing at elevated temperature, an unexpected deformation of the test piece is sometimes observed. More particularly, the two flat surfaces can be deformed, which complicates the thickness measurement. In this case, the diameter of the gauge use
40、d to measure the thickness should be chosen carefully to allow precise measurement. 4.5 Timing device, for measuring the recovery time, with a precision of 1 s a) Example 1 b) Example 2 Key 1 test piece 5 lower plate 2 spacer 6 part formed for clamping in a device 3 nut 7 locating pin 4 upper plate
41、8 screw Figure 1 Examples of assemblies for the determination of compression set 5 Calibration The test apparatus shall be calibrated in accordance with the schedule given in Annex B. ISO 2014 All rights reserved 3BS ISO 815-1:2014ISO 815-1:2014(E) 6 Test pieces 6.1 Dimensions The test pieces shall
42、be one of two sizes, designated type A and type B. Type A: a cylindrical disc of diameter 29,0 mm 0,5 mm and thickness 12,5 mm 0,5 mm. Type B: a cylindrical disc of diameter 13,0 mm 0,5 mm and thickness 6,3 mm 0,3 mm. These two types do not necessarily give the same values for compression set, and c
43、omparison of results obtained using test pieces of different sizes shall be avoided when comparing one compound with another. Type A test pieces are preferred for testing rubbers having low compression set, because of the greater accuracy attainable using these larger test pieces. Type B test pieces
44、 are preferred when it is required to cut test pieces from products. In this case, the test pieces shall be taken as near to the centre of the product as possible, unless otherwise specified. When possible, the test piece shall be cut in such a way that its axis is parallel to the direction of compr
45、ession of the product in service. 6.2 Preparation The test pieces shall be prepared by moulding each disc, whenever possible. Preparation by cutting out each disc or by laminating not more than three discs is permitted. The use of test pieces prepared by laminating several discs for control of finis
46、hed products shall be agreed between interested parties. Cutting shall be performed in accordance with ISO 23529. When cupping (the formation of a concave surface) is a problem, the test piece shape can be improved by cutting it in two stages: first, cut an oversize test piece, and then, trim it to
47、the exact dimensions with a second cutter. Laminated test pieces shall conform to the dimensions specified in 6.1 and shall be prepared by laminating discs or rubber cut from sheets without adhesives. Discs can be compressed by a few percent for 1 min so that they stick together. The number of discs
48、 laminated to produce a test piece shall not exceed three. The total thickness shall then be measured. Test pieces prepared by the various methods described above can give different results and comparison of values shall be avoided. NOTE Attention is drawn to the marked effects of the state of cure
49、on compression set values. It might be necessary to adjust the cure of moulded test pieces to be representative of different thicknesses of sheets or mouldings. 6.3 Number of test pieces A minimum of three test pieces shall be tested, separately or as a set. 6.4 Time interval between production and testing For all test purposes, the minimum time between production and testing shall be 16 h. For non-product tests, the maximum time between production and testing shall be 4 weeks and, f
