1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 248-1:2011Rubber, raw Determinationof volatile-matter contentPart 1: Hot-mill method and oven methodBS ISO 248-1:2011 BRITISH STANDARDNational forewordThis British Standar
2、d is the UK implementation of ISO 248-1:2011. Itsupersedes BS ISO 248:2005 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee PRI/23, Test methods for rubber and non-blackcompounding ingredients.A list of organizations represented on this committee can beo
3、btained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2011ISBN 978 0 580 66334 5ICS 83.040.10Compliance with a British Standard cannot confer immunity fromlegal obligations.Thi
4、s British Standard was published under the authority of theStandards Policy and Strategy Committee on 30 November 2011.Amendments issued since publicationDate Text affectedBS ISO 248-1:2011Reference numberISO 248-1:2011(E)ISO 2011INTERNATIONAL STANDARD ISO248-1First edition2011-10-15Rubber, raw Dete
5、rmination of volatile-matter content Part 1: Hot-mill method and oven method Caoutchouc brut Dtermination des matires volatiles Partie 1: Mthode par mlangeage chaud et mthode par tuvage BS ISO 248-1:2011ISO 248-1:2011(E) COPYRIGHT PROTECTED DOCUMENT ISO 2011 All rights reserved. Unless otherwise spe
6、cified, 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 office
7、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 Switzerland ii ISO 2011 All rights reservedBS ISO 248-1:2011ISO 248-1:2011(E) ISO 2011 All rights reserved iiiContents Page Foreword iv 1 Scope 1 2 Normative references
8、 1 3 Terms and definitions . 2 4 Principle . 2 5 Hot-mill method . 2 6 Oven method 4 7 Precision 6 8 Test report 7 Annex A (informative) Selection of appropriate test method . 8 Annex B (normative) Homogenization 9 Annex C (informative) Precision 10 Bibliography 13 BS ISO 248-1:2011ISO 248-1:2011(E)
9、 iv ISO 2011 All rights reservedForeword 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 inter
10、ested 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
11、 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 prepare International Standards. Draft International Standards adopted by the te
12、chnical 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 some of the elements of this document may be the subject of patent rights. IS
13、O shall not be held responsible for identifying any or all such patent rights. ISO 248-1 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee SC 2, Testing and analysis. This first edition cancels and replaces ISO 248:2005, which has been technically revised. ISO 2
14、48 consists of the following parts, under the general title Rubber, raw Determination of volatile-matter content: Part 1: Hot-mill method and oven method Part 2: Thermogravimetric methods using an automatic analyser with an infrared drying unit BS ISO 248-1:2011INTERNATIONAL STANDARD ISO 248-1:2011(
15、E) ISO 2011 All rights reserved 1Rubber, raw Determination of volatile-matter content Part 1: Hot-mill method and oven method WARNING Persons using this part of ISO 248 should be familiar with normal laboratory practice. This part of ISO 248 does not purport to address all of the safety problems, if
16、 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. IMPORTANT Certain procedures specified in this part of ISO 248 might involve the use or generation of substances,
17、 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 Scope 1.1 This part of ISO 248 specifies two methods for the determination of volatile-matter content in raw rubbers by us
18、ing a hot mill or an oven. 1.2 The methods are applicable to the determination of the volatile-matter content in the “R” group of rubbers listed in ISO 1629. These are rubbers having an unsaturated carbon chain, for example natural rubber and synthetic rubbers derived at least partly from diolefins.
19、 The methods can also be applicable to other raw rubbers, but in these cases it is necessary to demonstrate that the change in mass is due solely to loss of actual volatile matter and not to rubber degradation. 1.3 The hot-mill method is not applicable to natural rubber, to synthetic rubbers which a
20、re too difficult to handle on a hot mill or to synthetic rubbers in powder or chip form. 1.4 The test methods do not necessarily give identical results. Therefore, in cases of dispute, the oven method, procedure A, is the reference method. NOTE The applicability of each test method to various types
21、of rubber is summarized in Annex A. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments)
22、 applies. ISO 1629, Rubber and latices Nomenclature ISO 1795, Rubber, raw natural and raw synthetic Sampling and further preparative procedures ISO 2393, Rubber test mixes Preparation, mixing and vulcanization Equipment and procedures BS ISO 248-1:2011ISO 248-1:2011(E) 2 ISO 2011 All rights reserved
23、3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 1795 and the following apply. 3.1 test portion quantity of rubber taken from the test sample or laboratory sample for the purpose of a single specific test, for example the amount actually weighed out f
24、or a single determination of the volatile-matter content 4 Principle 4.1 Hot-mill method A test portion is sheeted out on a heated mill until all volatile matter is driven off. The loss in mass during milling is calculated and expressed as the volatile-matter content. If the test portion is homogeni
25、zed in accordance with Annex B before drying, the loss in mass during the homogenization is included in the calculation. 4.2 Oven method A test portion is dried in an oven to constant mass. The loss in mass is calculated and expressed as the volatile-matter content. If the test portion is homogenize
26、d in accordance with Annex B before drying, the loss in mass during the homogenization is included in the calculation. 5 Hot-mill method 5.1 General 5.1.1 Two procedures are specified, as follows: Hot-mill method, procedure A: A test sample is homogenized using a laboratory mill, and a test portion
27、from the homogenized test sample is dried to constant mass using a hot mill. Hot-mill method, procedure B: A test portion is dried to constant mass using a hot mill. NOTE Procedure B is a simplified one which does not include a homogenization process. 5.1.2 When the sample is flaky or becomes sticky
28、 on the hot mill, making weighing difficult or impossible, the oven method shall be used. 5.1.3 The number of test portions shall be agreed between the interested parties. 5.2 Apparatus 5.2.1 Mixing mill, complying with the requirements of ISO 2393. 5.2.2 Balance, capable of weighing to the nearest
29、0,1 g. 5.3 Procedure 5.3.1 Hot-mill method, procedure A 5.3.1.1 Take a test sample of about 250 g from the laboratory sample in accordance with ISO 1795 and homogenize it in accordance with Annex B. Weigh to the nearest 0,1 g before and after homogenization BS ISO 248-1:2011ISO 248-1:2011(E) ISO 201
30、1 All rights reserved 3(masses m1and m2, respectively). Cut test portions needed for other chemical and physical tests from the homogenized test sample, if necessary. 5.3.1.2 Adjust the clearance of the mill rolls to 0,25 mm 0,05 mm, using lead strips as specified in ISO 2393. Maintain the surface t
31、emperature of the rolls at 105 C 5 C. 5.3.1.3 Pass a weighed test portion (mass m3), preferably of 100 g or more, taken from the homogenized test sample repeatedly through the mill for 4 min. Do not allow the test portion to band and take care to prevent any loss of material. Weigh the test portion
32、to the nearest 0,1 g. Pass the test portion through the mill for an additional 2 min and reweigh. If the masses at the end of the 4 min and 6 min periods differ by less than 0,1 g, calculate the volatile-matter content. If not, continue passing the test portion through the mill for 2 min periods unt
33、il the mass does not decrease by more than 0,1 g between successive weighings (final mass m4). Before each weighing, allow the test portion to cool to room temperature in a desiccator. 5.3.2 Hot-mill method, procedure B 5.3.2.1 Take a test portion of about 250 g from the laboratory sample and weigh
34、to the nearest 0,1 g (mass m5). 5.3.2.2 Adjust the clearance of the mill rolls to 0,25 mm 0,05 mm, using lead strips as specified in ISO 2393. Maintain the surface temperature of the rolls at 105 C 5 C. Pass the test portion through the mill not less than twice, then reweigh to the nearest 0,1 g, fo
35、llowed by passing through the mill not less than twice again and reweighing. 5.3.2.3 If the difference in mass of the test portion before and after it is passed through the rolls is less than 0,1 g, the test portion is considered to be well dried. If it is not well dried, continue passing the test p
36、ortion twice through the rolls until the mass difference is less than 0,1 g (final mass m6). NOTE Cooling in a desiccator before weighing is desirable. 5.4 Expression of results 5.4.1 Hot-mill method, procedure A The volatile-matter content w1is given, as a percent mass fraction, by the formula: 241
37、1311mmwmm 0 where m1is the mass, in grams, of the test sample before homogenization; m2is the mass, in grams, of the test sample after homogenization; m3is the mass, in grams, of the test portion before milling; m4is the mass, in grams, of the test portion after milling. BS ISO 248-1:2011ISO 248-1:2
38、011(E) 4 ISO 2011 All rights reserved5.4.2 Hot-mill method, procedure B The volatile-matter content w2is given, as a percent mass fraction, by the following formula: 5625100mmwm where m5is the mass, in grams, of the test portion before milling; m6is the mass, in grams, of the test portion after mill
39、ing. 6 Oven method 6.1 General 6.1.1 Two procedures are specified, as follows: Oven method, procedure A: A test sample is homogenized using a laboratory mill, and a test portion taken from the homogenized test sample is dried in an oven to constant mass. If the sample is in powder form or impossible
40、 to weigh before and after homogenization, a test portion shall simply be dried, without carrying out the homogenization process. Oven method, procedure B: A test sample is sheeted out using a laboratory mill, and a test portion taken from the sheeted test sample is dried in an oven for 1 h. If the
41、sample is in powder form or is difficult to pass through the mill, the test portion shall simply be dried, without carrying out the sheeting process. This procedure is only applicable to synthetic rubbers since natural rubber requires homogenization. 6.1.2 The number of test portions shall be agreed
42、 between the interested parties. 6.2 Apparatus 6.2.1 Oven, ventilated, preferably of the air-circulation type, capable of being maintained at 105 C 5 C. 6.2.2 Balance, capable of weighing to the nearest 0,1 mg. 6.2.3 Mixing mill, complying with the requirements of ISO 2393. 6.3 Procedure 6.3.1 Oven
43、method, procedure A 6.3.1.1 Natural rubber 6.3.1.1.1 Take a test sample of about 600 g from the laboratory sample in accordance with ISO 1795 and homogenize it in accordance with Annex B. Weigh the test sample to the nearest 0,1 g before and after this homogenization (masses m7and m8, respectively).
44、 Allow to cool to room temperature before the final weighing. Cut test portions needed for other chemical and physical tests from the homogenized test sample, if necessary. 6.3.1.1.2 Take a test portion of about 10 g from the homogenized test sample and weigh it to the nearest 1 mg (mass m9). BS ISO
45、 248-1:2011ISO 248-1:2011(E) ISO 2011 All rights reserved 56.3.1.1.3 Pass the test portion twice through the mill with the rolls set at 70 C 5 C and with a mill opening which will produce a sheet of less than 2 mm thickness. 6.3.1.1.4 Dry the test portion for 1 h in the oven, maintained at 105 C 5 C
46、, with the ventilators open and with the air-circulating fan, if fitted, switched on. Arrange the test portion so as to present the largest possible surface area to the hot air. Allow to cool to room temperature in a desiccator and weigh. Repeat the heating for further 30 min periods until the mass
47、does not decrease by more than 1 mg between successive weighings (final mass m10). 6.3.1.1.5 If the sample is in powder form, take a test portion of about 10 g at random and place it on a clean watch-glass or a clean aluminium tray to facilitate weighing. Weigh it to the nearest 1 mg (mass m9). Dry
48、the test portion in accordance with 6.3.1.1.4 and weigh to the nearest 1 mg (final mass m10). 6.3.1.2 Synthetic rubber 6.3.1.2.1 Take a test sample of about 250 g from the laboratory sample in accordance with ISO 1795 and homogenize it in accordance with Annex B. Weigh the test sample to the nearest
49、 0,1 g before and after this homogenization (masses m7and m8, respectively). Cut test portions needed for other chemical and physical tests from the homogenized test sample, if necessary. 6.3.1.2.2 Take a test portion of about 10 g from the homogenized test sample and weigh it to the nearest 1 mg (mass m9). 6.3.1.2.3 Pass the test portion twice through the mill with the rolls set at 70 C 5 C and with a mill opening which will produce a sheet of less than 2 mm thick
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