bsi standards publication determination of dirt content

BS ISO 249:2016

Rubber, raw natural —Determination of dirt content

BSI Standards Publication

WB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06

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BS ISO 249:2016 BRITISH STANDARD

National foreword

This British Standard is the UK implementation of ISO 249:2016. Itsupersedes BS ISO 249:2014 which is withdrawn.

The UK participation in its preparation was entrusted to TechnicalCommittee PRI/50, Raw materials (including latex) for use in therubber industry.

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. Users are responsible for its correctapplication.

© The British Standards Institution 2016. Published by BSI StandardsLimited 2016

ISBN 978 0 580 92668 6

ICS 83.040.10

Compliance with a British Standard cannot confer immunity fromlegal obligations.

This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 July 2016.

Amendments issued since publication

Date Text affected



BS ISO 249:2016

© ISO 2016

Rubber, raw natural — Determination of dirt contentCaoutchouc naturel brut — Détermination de la teneur en impuretés

INTERNATIONAL STANDARD

ISO249

Fifth edition2016-07-01

Reference numberISO 249:2016(E)



BS ISO 249:2016

ISO 249:2016(E)

ii © ISO 2016 – All rights reserved

COPYRIGHT PROTECTED DOCUMENT

© ISO 2016, Published in SwitzerlandAll 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. Permission can be requested from either ISO at the address below or ISO’s member body in the country of the requester.

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BS ISO 249:2016

ISO 249:2016(E)

Foreword ........................................................................................................................................................................................................................................iv1 Scope ................................................................................................................................................................................................................................. 12 Normative references ...................................................................................................................................................................................... 13 Reagents ........................................................................................................................................................................................................................ 14 Apparatus ..................................................................................................................................................................................................................... 25 Procedure..................................................................................................................................................................................................................... 2

5.1 Preparation of the test portion ................................................................................................................................................. 25.2 Preparation of the peptizer .......................................................................................................................................................... 35.3 Determination ......................................................................................................................................................................................... 35.4 Care of sieves ............................................................................................................................................................................................ 5

6 Expression of results ........................................................................................................................................................................................ 67 Precision ....................................................................................................................................................................................................................... 68 Test report ................................................................................................................................................................................................................... 6Annex A (informative) Guidance for using precision results ...................................................................................................... 7Annex B (informative) Precision ............................................................................................................................................................................... 8Bibliography .............................................................................................................................................................................................................................10

© ISO 2016 – All rights reserved iii

Contents Page



BS ISO 249:2016

ISO 249:2016(E)

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 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 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 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 editorial 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 rights 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 explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html

The committee responsible for this document is ISO/TC 45, Rubber and rubber products, Subcommittee SC 3, Raw materials (including latex) for use in the rubber industry.

This fifth edition cancels and replaces the fourth edition (ISO 249:2014), of which constitutes a minor revision with the following change:

— the first sentence of 5.1.1 has been corrected.

iv © ISO 2016 – All rights reserved


http://www.iso.org/directives

http://www.iso.org/patents

http://www.iso.org/iso/foreword.html


BS ISO 249:2016

INTERNATIONAL STANDARD ISO 249:2016(E)

Rubber, raw natural — Determination of dirt contentWARNING — 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 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 a method for the determination of the dirt content of raw natural rubber.

It is not applicable to dirt present as surface contamination.

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 referenced document (including any amendments) applies.

ISO 565, Test sieves — Metal wire cloth, perforated metal plate and electroformed sheet — Nominal sizes of openings

ISO 1795, Rubber, raw natural and raw synthetic — Sampling and further preparative procedures

3 Reagents

WARNING — All recognized health and safety precautions shall be exercised during the operations of this analysis, with particular emphasis on safe handling of the flammable solvents required. All solvents shall be free from water and dirt.

During the analysis, wherever possible, use only reagents of recognized analytical grade.

3.1 Mixed xylenes, boiling range 139 °C to 141 °C.

3.2 High-aromatic hydrocarbon solvent known as white spirit, boiling range 155 °C to 198 °C, or other hydrocarbon solvents of similar boiling range.

3.3 Light petroleum, boiling range 60 °C to 80 °C or other hydrocarbon solvents of similar boiling range.

3.4 Toluene.

3.5 Rubber peptizing agents.

3.5.1 Xylyl mercaptan solution, a mass fraction of 36 % in mineral oil.

3.5.2 2-mercaptobenzothiazole.

3.5.3 Di-(2-benzamidophenyl) disulfide.

© ISO 2016 – All rights reserved 1



bsi standards publication determination of dirt content

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