1、BSI Standards PublicationBS ISO 815-2:2014Rubber, vulcanized orthermoplastic Determinationof compression setPart 2: At low temperaturesBS ISO 815-2:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 815-2:2014. Itsupersedes BS ISO 815-2:2008 which is withdraw
2、n.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 not purport to include all the necessaryprovisions of a contract. Us
3、ers are responsible for its correctapplication. The British Standards Institution 2014. Published by BSI StandardsLimited 2014ISBN 978 0 580 78735 5ICS 83.060Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of the
4、Standards Policy and Strategy Committee on 30 November 2014.Amendments issued since publicationDate Text affectedBS ISO 815-2:2014 ISO 2014Rubber, vulcanized or thermoplastic Determination of compression set Part 2: At low temperaturesCaoutchouc vulcanis ou thermoplastique Dtermination de la dformat
5、ion rmanente aprs compression Partie 2: basses tempraturesINTERNATIONAL STANDARDISO815-2Second edition2014-11-01Reference numberISO 815-2:2014(E)BS ISO 815-2:2014ISO 815-2:2014(E)ii ISO 2014 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2014All rights reserved. Unless otherwise specified, no p
6、art 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. Permission can be requested from either ISO at the address below or ISOs member
7、body in the country of the requester.ISO copyright officeCase 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 815-2:2014ISO 815-2:2014(E)Contents PageForeword ivIntroduction v1 Scope . 12 Normative references
8、 13 Principle 13.1 Method 1. 13.2 Method 2. 24 Apparatus for low temperature tests 24.1 Method 1. 24.2 Method 2. 45 Calibration 66 Test pieces . 66.1 Dimensions . 66.2 Preparation 76.3 Number 76.4 Time interval between production and testing 76.5 Conditioning 77 Test conditions . 87.1 Duration of te
9、st . 87.2 Temperature of test . 88 Procedure. 88.1 Method 1. 88.2 Method 2. 99 Expression of results .1010 Precision 1011 Test report 10Annex A (normative) Calibration schedule 12Bibliography .16 ISO 2014 All rights reserved iiiBS ISO 815-2:2014ISO 815-2:2014(E)ForewordISO (the International Organiz
10、ation 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 interested in a subject for which a technical committee has been established
11、 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 Commission (IEC) on all matters of electrotechnical standardization.Th
12、e procedures used to develop this document and those intended for its further maintenance 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 e
13、ditorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).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 r
14、ights identified during the development of the document will be in the Introduction 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 ex
15、planation on the meaning of ISO specific terms and expressions related to conformity 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 informationThe committee responsible for this do
16、cument is ISO/TC45, Rubber and rubber products, SC 2, Testing and analysis.This second edition cancels and replaces the first edition (ISO 815-2:2008), which has been technically revised, mainly by addition of method 1 and a calibration schedule (Annex A).ISO 815 consists of the following parts, und
17、er the general title Rubber, vulcanized or thermoplastic Determination of compression set: Part 1: At ambient or elevated temperatures Part 2: At low temperaturesiv ISO 2014 All rights reservedBS ISO 815-2:2014ISO 815-2:2014(E)IntroductionAllowing measurement and recording of the compression set at
18、low temperature is very sensitive to testing conditions, and the values obtained can differ a lot especially for type B test pieces. That is why two measurement methods have been introduced. Method 2 generally gives a higher compression set than method 1, and this difference should be taken into acc
19、ount when preparing material specifications.Those 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 altern
20、ative 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. ISO 2014 All rights reserved vBS ISO 815-2:2014ISO 815-2:2014(E)vi I
21、SO 2014 All rights reservedBS ISO 815-2:2014Rubber, vulcanized or thermoplastic Determination of compression set Part 2: At low temperaturesWARNING 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 saf
22、ety 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.WARNING 2 Certain procedures specified in this part of ISO 815 can involve the use of generation o
23、f substances, or the generation of waste, that could constitute a local environmental hazard. Reference should be made to appropriate documentation on safe handling and disposal after use.1 ScopeThis part of ISO 815 specifies two methods for the determination of the compression set characteristics o
24、f vulcanized and thermoplastic rubbers at low temperatures.Method 1 derives from the methodology used in ISO 815-1. Method 2 uses a specified testing device, allowing to measure and record the test piece thickness during recovery. Due to the load applied during recovery in method 2, no correlation c
25、an be established between the results given by both methods.NOTE When rubber is held under compression, physical or chemical changes can occur that prevent the rubber returning to its original dimensions after release of the deforming force. The result is a set, where the magnitude of which depends
26、on the time and temperature of compression as well as on the time, temperature, and conditions of recovery. At low temperatures, changes resulting from the effects of glass hardening or crystallization become predominant and, since these effects are reversed by raising the temperature, it is necessa
27、ry for all measurements to be undertaken at the test temperature.2 Normative referencesThe 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, th
28、e latest edition of the referenced document (including any amendments) applies.ISO 18899:2013, Rubber Guide to the calibration of test equipmentISO 23529:2010, Rubber General procedures for preparing and conditioning test pieces for physical test methods3 Principle3.1 Method 1A test piece of known t
29、hickness is compressed at standard laboratory temperature to a defined strain, which is then maintained constant for a specified time at a fixed low temperature. The compression is totally released and, after the test piece has been allowed to freely recover at the same fixed low temperature, the th
30、ickness of the test piece is again measured.INTERNATIONAL STANDARD ISO 815-2:2014(E) ISO 2014 All rights reserved 1BS ISO 815-2:2014ISO 815-2:2014(E)3.2 Method 2A test piece of known thickness is compressed at standard laboratory temperature to a defined strain, which is then maintained constant for
31、 a specified time at a fixed low temperature. The compression is released and the test piece is allowed to recover at this temperature under a given pressure according to ISO 23529:2010 for thickness measurement. The thickness is measured either at intervals after the release of the strain (so that
32、an assessment of compression set characteristics can be obtained by plotting of recovery against time at the low temperature) or a specified time after the release of the strain.4 Apparatus for low temperature tests4.1 Method 14.1.1 Compression assembly, consisting of compression plates, steel space
33、rs, and clamping device. A typical assembly is shown in Figure 1. A quick release mechanism as shown on Figure 2 may also be used.4.1.1.1 Compression plates, comprising a pair of parallel, flat, highly polished chromium-plated steel or highly polished stainless-steel plates, between the faces of whi
34、ch the test piece is compressed. The plates 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
35、 plates.NOTE A surface finish not worse 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.4.1.1.2 Steel spacer(s), to provide the required compression, if necessary. Whether spacer(s) will need to be used or not will depend on
36、 the design of the compression apparatus.If used, the spacer(s) shall be of such size and shape that contact with the compressed test piece is avoided.The height of 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
37、hardnesses between 80 IRHD and 89 IRHD, (10 1) % for hardnesses of 90 IRHD and higher.4.1.1.3 Clamping device, a simple screw device (Figure 1) or a clamping device as shown on Figure 2 are adequate.4.1.2 Low-temperature cabinet, capable of maintaining the compression apparatus and test pieces at th
38、e test temperature within the tolerance limits specified in 7.2. The low-temperature cabinet can be mechanically refrigerated or it can be cooled directly by dry ice or liquid nitrogen.The cabinet shall be designed so that it is possible to release the test pieces and carry out the subsequent thickn
39、ess measurements without direct contact, e.g. by means of hand-holes fitted with gloves or a remote-handling device. The cabinet shall be capable of maintaining the temperature within specified limits while these operations are being carried out.The time to reach a steady-state temperature depends o
40、n the type of cabinet and the overall heat capacity of the compression apparatus. To obtain test results which can be compared with each other, it is necessary, in the case of a 24 h test duration, to reach the steady-state temperature within the specified limits in the interior of the test pieces i
41、n not more than 3 h.2 ISO 2014 All rights reservedBS ISO 815-2:2014ISO 815-2:2014(E)4.1.3 Pair of tongs, for handling the test pieces.4.1.4 Thickness gauge, with an accuracy of 0,01 mm (see ISO 23529:2010, 7.1), having a flat solid base-plate and exerting a pressure of 22 kPa 5 kPa for solid rubber
42、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. For comparative tests, the same dimensions of the circular foot shall be used.NOTE When using a digital gauge, a resolution of 0,001 mm is needed to obtain the required accuracy.4.1.5 Ti
43、ming device, for measuring the recovery time, with a precision of 1 sKey1 test piece 5 lower plate2 spacer 6 part formed for clamping in a vice3 nut 7 locating pin4 upper plate 8 screwFigure 1 Example of assembly for the determination of compression set ISO 2014 All rights reserved 3BS ISO 815-2:201
44、4ISO 815-2:2014(E)Figure 2 Example of a quick-release mechanism4.2 Method 24.2.1 Compression apparatus, consisting of compression plates, spacer(s) (optional), a thickness gauge, a temperature sensor, and a device for applying a specified pressure for thickness measurements. The measurement pressure
45、 for thickness measurements is the same as that specified in ISO 23529:2010.The compression apparatus shall be capable of applying the compression and maintaining it during the whole duration of the test, and it shall be possible to keep the apparatus in a low-temperature cabinet at the specified te
46、st temperature. Care shall be taken to ensure that there is as little influence on the test as possible by conduction of heat away from the test piece, for example, through metal parts which are connected with the outside of the low-temperature cabinet.The part of the apparatus with the compression
47、plates and the test piece shall be within the low-temperature cabinet during the whole of the test, but the thickness gauge may be located outside the cabinet.An example of a compression apparatus is shown in Figure 3.It shall be possible to release the compression of the test piece without opening
48、the low-temperature cabinet.4.2.1.1 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 plates shall be sufficiently rigid to ensure that, with a test pie
49、ce 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 not worse 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 ISO 2014 All rights reservedBS ISO 815-2:2014ISO 815-2:2014(E)4.2.1.2 Steel spacer(s), to provide the required compression, if necessary. Wh
