1、BSI Standards PublicationBS ISO 17278:2013Rubber, raw natural Determination of the gelcontent of technically specifiedrubber (TSR)BS ISO 17278:2013 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 17278:2013.The UK participation in its preparation was entrusted
2、to TechnicalCommittee PRI/23, Test methods for rubber and non-blackcompounding ingredients.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 fo
3、r its correctapplication. The British Standards Institution 2013. Published by BSI StandardsLimited 2013ISBN 978 0 580 77068 5ICS 83.040.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy an
4、d Strategy Committee on 31 August 2013.Amendments issued since publicationDate Text affectedBS ISO 17278:2013 ISO 2013Rubber, raw natural Determination of the gel content of technically specified rubber (TSR)Caoutchouc naturel brut Dtermination de la teneur en gel des caoutchoucs spcifis techniqueme
5、nt (TSR)INTERNATIONAL STANDARDISO17278First edition2013-08-15Reference numberISO 17278:2013(E)BS ISO 17278:2013ISO 17278:2013(E)ii ISO 2013 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2013All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utiliz
6、ed 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 body in the country of the requester.ISO copyright
7、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 17278:2013ISO 17278:2013(E) ISO 2013 All rights reserved iiiContents PageForeword iv1 Scope . 12 Normative references 13 Principle 14 Terms and defin
8、itions . 15 Reagent . 16 Apparatus . 27 Conditions 28 Procedure. 28.1 Number of test samples . 28.2 Procedure 29 Expression of the result.310 Precision .311 Test report .3Annex A (informative) Precision . 5Bibliography 7BS ISO 17278:2013ISO 17278:2013(E)ForewordISO (the International Organization fo
9、r 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
10、 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 proced
11、ures 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
12、 rules of the ISO/IEC Directives, Part 2. www.iso.org/directivesAttention 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 identifi
13、ed during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received. www.iso.org/patentsAny trade name used in this document is information given for the convenience of users and does not constitute an endorsement.The committee responsible for
14、 this document is ISO/TC 45, Rubber and rubber products, Subcommittee SC 3, Raw materials (including latex) for use in the rubber industry.iv ISO 2013 All rights reservedBS ISO 17278:2013INTERNATIONAL STANDARD ISO 17278:2013(E)Rubber, raw natural Determination of the gel content of technically speci
15、fied rubber (TSR)1 ScopeThis International Standard specifies a method for the determination of gel content for technically specified rubbers (TSR).WARNING Persons using this International Standard should be familiar with normal laboratory practice. This International Standard does not purport to ad
16、dress 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.2 Normative referencesThe following documents, in whole or in part, are normat
17、ively referenced in this document and are indispensable to 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 2000,1)Rubber, raw natural Guidelines for the specification o
18、f technically specified rubber (TSR)ISO 23529, Rubber General procedures for preparing and conditioning test pieces for physical test methods3 PrincipleAn LoV-TSR sample is dissolved in toluene under specified conditions, and the gel content is calculated as the percentage mass fraction of the insol
19、uble part of the rubber.4 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.4.1technically specified rubberTSRnatural rubber obtained from the latex of Hevea brasiliensis (typically processed into block rubber), and having properties complying with the
20、 criteria for the grade concerned5 ReagentUse only reagents of recognized analytical grade.5.1 Toluene, analytical grade.CAUTION The solvent might evaporate from the flask or tube when it is handled. Therefore, handling this solvent should be done only when permitted by local health and safety regul
21、ation and only in a well-ventilated appropriate place.1) Under preparation. (Revision of ISO 2000:2003) ISO 2013 All rights reserved 1BS ISO 17278:2013ISO 17278:2013(E)6 Apparatus6.1 Laboratory centrifuge, capable of rotating at a minimum of 14 000 r/min (revolutions per minute).If the above speed c
22、annot be attained a minimum speed of 8 000 r/min may be used with a longer running time (8.2.4).NOTE When the centrifugal rotational frequency (rotational speed) is 14 000 r/min, the gravitational acceleration is 22 000 G. When the centrifugal rotation speed is 8 000 r/min, the gravitational acceler
23、ation is 7 000 G.6.2 Screw-cap centrifuge tubes, with a minimum capacity of 30 cm3, capable of withstanding the centrifuge conditions and of being heated to a temperature greater than 110 C.6.3 Balance, capable of accurately weighing to 0,1 mg.6.4 Laboratory oven, gravity convection type, capable of
24、 controlling the temperature to 10 C.6.5 Weighing container, i.e. an aluminium box or plate for weighing.7 ConditionsLaboratory conditions shall be controlled in accordance with ISO 23529.8 Procedure8.1 Number of test samplesTwo samples shall be taken in accordance with Clause 7 of ISO 2000.1)8.2 Pr
25、ocedure8.2.1 Take a test sample from a bale without milling of mass calculated at the ratio of 0,1 g per 30 cm3of toluene.NOTE When the volume of a centrifuge tube is 50 cm3, the volume of toluene is 30 cm3(see 8.2.3), and the sample weight is 0,1 g.8.2.2 Cut the test sample into approximately 1 mm3
26、-sized pieces using clean scissors. Weigh the prepared test sample to the nearest 0,1 mg (mo). Place the pieces in a clean centrifuge tube (6.2), which has previously been heated at 100 C for 1 h and stored in a desiccator.8.2.3 Add toluene to the tube until it is 60 % full. Cap it and shake by hand
27、 for a few seconds. Then, allow it to stand for 16 h to 20 h in dark conditioms without stirring at (25 2) C.8.2.4 After this period, shake the tube up and down for 60 s to disperse the jelly-like precipitate on the bottom.Before placing the tubes in the centrifuge machine, all tubes shall be filled
28、 up with fresh toluene, so that the volume of solution is the same in all tubes.NOTE A centrifuge tube is usually filled up with solution to minimize the dead space created at the top of the tube because of the vacuum-pressured environment during rotation.Place the tubes in the centrifuge machine an
29、d operate the machine at 14 000 r/min for 2 h.If the rotating capacity of the centrifuge machine is below 14 000 r/min, operate the machine at 8 000 r/min for 6 h.2 ISO 2013 All rights reservedBS ISO 17278:2013ISO 17278:2013(E)A set temperature of centrifuge is usually indicated in the operation man
30、ual for safety reasons. If not, it may be set to between 0 C and 25 C.8.2.5 Remove the tube from the machine and pipette the liquid from the tube held at approximately 45. Caution shall be taken to prevent pipetting the precipitate.8.2.6 Add 1 ml to 3 ml of acetone to the precipitate so that it can
31、be easily peeled from the bottom of the tube. Leave to stand for over 30 s and then pipette the liquid from the tube.8.2.7 Peel off the precipitate remaining at the bottom of the tube with a spatula or a spatula-like stick and move it into the container (6.5) which has been cleaned and weighed to th
32、e nearest 1 mg (m1). A limited amount of acetone may be used to rinse the spatula, if necessary.8.2.8 Store the container in a fume cupboard for 30 min to allow the solvent to evaporate, in order to prevent flashing of the solvent during heating. Place the container containing the precipitate in the
33、 oven and dry it at the temperature of 110 C for 1 h.8.2.9 Take the container out of the oven and allow it to cool in a desiccator for 30 min.8.2.10 Weigh the container containing the dry precipitate to the nearest 0,1 mg (m2).8.2.11 Repeat the procedure in 8.2.8, 8.2.9 and 8.2.10 until the loss in
34、mass between two successive weighings is less than 0,2 mg. Note the period of drying time for the first test piece and use it for the next test piece for the series of testing. Record the final mass (m2).9 Expression of the resultTo determine the gel content, use Formula (1) and round the result to
35、one decimal place.Gmmm=()210100 (1)whereG is the gel content, as a percentage (%);mois the mass of the original test piece (8.2.2), in grams (g);m1is the mass of the empty container (8.2.7), in grams (g);m2is the mass of the container containing dry precipitate (8.2.10), in grams (g).Take an average
36、 of two gel content values.10 PrecisionFor the precision, see Annex A.11 Test reportThe test report shall include the following:a) a reference to this International Standard, i.e. ISO 17278.b) all details necessary for identification of the test sample;c) the test method;d) the laboratory temperatur
37、e; ISO 2013 All rights reserved 3BS ISO 17278:2013ISO 17278:2013(E)e) the centrifuge diameter, the temperature, the speed and the running time of the test;f) details of any operation not specified in this International Standard;g) the results;h) the number of test pieces tested;i) the individual tes
38、t results;j) the mean result;k) the details of any unusual features noted during the determination;l) the date of the test.4 ISO 2013 All rights reservedBS ISO 17278:2013ISO 17278:2013(E)Annex A (informative) PrecisionA.1 GeneralAn interlaboratory test programme (ITP) for the precision evaluation of
39、 the test method for TSR gel content was planned and conducted in January and February of 2011. The calculations were carried out in accordance with ISO/TR 9272. Ten laboratories from five countries participated in this ITP.Three TSR samples with different levels of gel content were prepared for thi
40、s ITP as shown in Table A.1. They were sent out to each laboratory with instructions to carry out the test as soon as the samples were received. The test was carried out on two different days at one-week intervals with two tests each day (n = 2).The precision results as determined by this ITP should
41、 not be used for acceptance/rejection testing of any group of materials or products without documentation that the results are applicable to those particular materials or products and the specific test protocol of this test method.Table A.1 TSR sampleSample A Sample B Sample CGel content level Low M
42、edium HighNOTE Each sample should be appropriately stored in a conditioned place until all the tests are completed.The precision results are given in Table A.2. These results were obtained using outlier deletion procedures as described in ISO/TR 9272.A.2 RepeatabilityThe repeatability, r, of the tes
43、t method was established as the appropriate value tabulated in Table A.2 for each material. Two single test results that differ by more than the value shall be considered suspect, and it is recommended that some appropriate investigative action be taken.A.3 ReproducibilityThe reproducibility, R, of
44、the test method was established as the appropriate value tabulated in Table A.2 for each material. Two single test results that differ by more than the value shall be considered suspect, and it is recommended that some appropriate investigative action be taken. ISO 2013 All rights reserved 5BS ISO 1
45、7278:2013ISO 17278:2013(E)Table A.2 Precision for gel contentMaterial Mean%Within laboratory Between laboratories Number of laboratoriessrr (r) sRR (R)A 0,80 0,14 0,39 48,8 0,45 1,27 158,8 8B 5,20 0,26 0,75 14,4 1,52 4,31 82,9 8C 8,20 0,56 1,57 19,1 2,02 5,71 69,6 9Number of replicates n = 2;sris th
46、e repeatability standard deviation;sRis the reproducibility standard deviation;r is the repeatability, in measurement units;(r) is the repeatability, as a percentage (these values represent relative percentage, i.e. per cent of a percent);R is the reproducibility, in measurement units;(R) is the rep
47、roducibility, as a percentage (these values represent relative per cent, i.e. per cent of a percent).6 ISO 2013 All rights reservedBS ISO 17278:2013ISO 17278:2013(E)Bibliography1 ISO/TR 9272, Rubber and rubber products Determination of precision for test method standards ISO 2013 All rights reserved
48、 7BS ISO 17278:2013ISO 17278:2013(E) ISO 2013 All rights reservedICS 83.040.10Price based on 7 pagesThis page deliberately left blankBSI is the national body responsible for preparing British Standards and other standards-related publications, information and services.BSI is incorporated by Royal Ch
49、arter. British Standards and other standardization products are published by BSI Standards Limited.British Standards Institution (BSI)BSI Group Headquarters389 Chiswick High Road London W4 4AL UKAbout usWe bring together business, industry, government, consumers, innovators and others to shape their combined experience and expertise into standards -based solutions.The knowledge embodied in our standards has been carefully assembled in a dependable format and refined through our open consultation pr
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