Reclaimed rubber derived from products containing mainly natural rubber Evaluation procedure

Transcription

1 ISO 2012 All rights reserved ISO/TC 45/SC 3 N 1238 Date: ISO/PDTS ISO/TC 45/SC 3/WG 5 Secretariat: AFNOR Reclaimed rubber derived from products containing mainly natural rubber Evaluation procedure Caoutchouc régénéré dérivé principalement de produits contenant du caoutchouc naturel Méthode d'évaluation Warning This document is not an ISO International Standard. It is distributed for review and comment. It is subject to change without notice and may not be referred to as an International Standard. Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to provide supporting documentation. Document type: Technical Specification Document subtype: Document stage: (20) Preparatory Document language: E C:\Documents and Settings\HC\Bureau\Absence du 30 mai au 4 juin\isotc45sc3\iso_np_16095_(e).doc STD Version alpha3

2 Copyright notice This ISO document is a working draft or committee draft and is copyright-protected by ISO. While the reproduction of working drafts or committee drafts in any form for use by participants in the ISO standards development process is permitted without prior permission from ISO, neither this document nor any extract from it may be reproduced, stored or transmitted in any form for any other purpose without prior written permission from ISO. Requests for permission to reproduce this document for the purpose of selling it should be addressed as shown below or to ISO's member body in the country of the requester: [Indicate the full address, telephone number, fax number, telex number, and electronic mail address, as appropriate, of the Copyright Manager of the ISO member body responsible for the secretariat of the TC or SC within the framework of which the working document has been prepared.] Reproduction for sales purposes may be subject to royalty payments or a licensing agreement. Violators may be prosecuted. ii ISO 2012 All rights reserved

3 Contents Page Foreword... iv 1 Scope Normative references Sampling and sample preparation Physical and chemical tests on raw rubber Mooney viscosity Acetone extract Ash Carbon black Rubber content Preparation of test mixes for evaluation Standard test formulation Mixing procedure Single stage mixing using open mixing mill Evaluation of vulcanization characteristics by a curemeter test Using an oscillating-disc curemeter Using a rotorless curemeter Evaluation of Mooney viscosity of test mixes Evaluation of tensile stress-strain properties of vulcanized test mixes Evaluation of Shore hardness of vulcanized test mixes Test report... 5 Bibliography... 6 ISO 2012 All rights reserved iii

4 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. 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 technical 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. In other circumstances, particularly when there is an urgent market requirement for such documents, a technical committee may decide to publish other types of normative document: an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in an ISO working group and is accepted for publication if it is approved by more than 50 % of the members of the parent committee casting a vote; an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting a vote. An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is confirmed, it is reviewed again after a further three years, at which time it must either be transformed into an International Standard or be withdrawn. 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. ISO/TS was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee SC 3, Raw materials (including latex) for use in the rubber industry. ISO/TC 45/SC 3 decided to publish a Technical Specification, because the result of the inter-laboratory test procedure (ITP) to validate the evaluation procedure on reclaimed isobutene-isoprene rubber may be dubious. If the result of this ITP shows that the procedure is reproductible and reproducible, then this Technical Specification will be converted in an International Standard. iv ISO 2012 All rights reserved

5 WORKING DRAFT ISO/PDTS Reclaimed rubber derived from products containing mainly natural rubber Evaluation procedure 1 Scope This International Technical Specification specifies: physical and chemical tests on raw natural reclaimed rubber; standard materials, standard test formulations, equipment and processing methods for evaluating the vulcanization characteristics and the mechanical properties of natural reclaimed rubber. 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) applies. ISO 37, Rubber, vulcanized or thermoplastic Determination of tensile stress-strain properties ISO 247:2006, Rubber Determination of ash ISO 289-1, Rubber, unvulcanized Determinations using a shearing-disc viscometer Part 1: Determination of Mooney viscosity ISO 1407:2011, Rubber Determination of solvent extract ISO 1795, Rubber, raw natural and raw synthetic Sampling and further preparative procedures ISO 3417, Rubber Measurement of vulcanization characteristics with the oscillating disc curemeter ISO 6502, Rubber Guide to the use of curemeters ISO , Rubber, vulcanized or thermoplastic Determination of indentation hardness Part 1: Durometer method (Shore hardness) ISO 23529, Rubber General procedures for preparing and conditioning test pieces for physical test methods ASTM D (2006), Standard Test Methods for Rubber Products Chemical Analysis 3 Sampling and sample preparation 3.1 Take a laboratory sample of approximately 1,5 kg by the method described in ISO Prepare the test portion in accordance with ISO ISO 2012 All rights reserved 1

6 4 Physical and chemical tests on raw rubber 4.1 Mooney viscosity Determine the Mooney viscosity in accordance with ISO 289-1, on a test portion prepared as indicated in 3.2. Record the result as ML(1 + 4) at 100 C. 4.2 Acetone extract Determine the acetone extract in accordance with method A or method B of ISO 1407: Ash Determine the ash in accordance with method A of ISO 247: Carbon black Determine the carbon black content in accordance with ASTM D297-93, Part A, Clause Rubber content Determine the rubber content, R (in %), in accordance with ASTM D297-93, Part A, Clauses 11, 12 and 13. R =100 (a +b + c) where: a is the carbon black content, in percent (%); b is the ash content, in percent (%); c is the acetone extract, in percent (%). 5 Preparation of test mixes for evaluation 5.1 Standard test formulation The standard test formulation for evaluation of natural reclaimed rubber is given in Table 1. The materials used shall be national or international standard reference materials. If no standard reference material is available, the materials to be used shall be agreed between the interested parties. 2 ISO 2012 All rights reserved

7 Table 1 Standard test formulation Material Natural reclaimed rubber Parts by mass 100,00 + x + y + z Stearic acid a 2,00 Zinc oxide a 5,00 Sulfur a 3,00 Mercaptobenzothiazole (MBT) 0,50 Diphenyl guanldine (DPG) 0,20 Total 110,70 + x + y + z x is the number of parts of carbon black to 100 parts of rubber in natural reclaimed rubber. y is the number of parts of acetone extract to 100 parts of rubber in natural reclaimed rubber. z is the number of parts of ash to 100 parts of rubber in natural reclaimed rubber. a Powder materials are used (standard curing ingredients used in the industry). 5.2 Mixing procedure Single stage mixing using open mixing mill The mixing temperature is the ambient temperature. a) Weigh accurately natural reclaimed rubber b) Weigh accurately activators and curatives according to the test recipe given above in proportion to the amount of reclaim used. c) Set the rolls of the mill to give a small freely rolling bank of the reclaim not greater than 12,5 mm in diameter. d) The mill rolls shall be cool and at ambient temperature. e) As soon as the reclaim bands on the mill and forms a smooth sheet, add activators and curatives, spreading across the full width of the roll gradually for good dispersion. f) Collect any material that has fallen into the mill-pan, deposit it on the batch sheet and pass it through the mill. Repeat this until all the ingredients have been incorporated. g) Cut batch from side to side alternatively approximately six times each direction. h) Roll batch and insert endwise six times. i) Sheet out the batch to a thickness of about 6 mm and cool the sheet. j) Condition the compound for 2 h to 24 h at ambient temperature. k) After conditioning pass the compound through the rolls of the mixing mill at ambient temperature, rolling endwise three times, and sheet out to the thickness of about 2,5 mm. l) Mould the slab at 140 C for 20. ISO 2012 All rights reserved 3

8 6 Evaluation of vulcanization characteristics by a curemeter test 6.1 Using an oscillating-disc curemeter Measure the following standard test parameters: ML, MH at defined time, ts1, t'c(50), t'c(90) and t'c(95) in accordance with ISO 3417, using the following test conditions: oscillation frequency: amplitude of oscillation: 1,7 Hz (100 cycles per minute) 3 of arc An amplitude of oscillation of 3 of arc is permitted as an alternative. If such an amplitude is chosen, measure ts2 instead of ts1. selectivity: to be chosen to give at least 75 % of full-scale deflection at MH die temperature: Trials to be done at 140 C pre-heat time: none 6.2 Using a rotorless curemeter Measure the following standard test parameters: FL, Fmax at defined time, ts1, t'c(50), t'c(90) and t'c(95) in accordance with ISO 6502, using the following test conditions: oscillation frequency: amplitude of oscillation: 1,7 Hz (100 cycles per minute) 0,5 of arc An amplitude of oscillation of 1 of arc is permitted as an alternative. If such an amplitude is chosen, measure ts2 instead of ts1. selectivity: to be chosen to give at least 75 % of full-scale deflection at Fmax die temperature: 140 C ± 0,3 C pre-heat time: none The two types of curemeter may not give identical results. 7 Evaluation of Mooney viscosity of test mixes Determine the Mooney viscosity in accordance with ISO Record the result as ML(1 + 4) at 100 C. 4 ISO 2012 All rights reserved

9 8 Evaluation of tensile stress-strain properties of vulcanized test mixes WARNING Formation of nitrosamines is possible during the cure. Vulcanize sheets at 140 C for 20. For hardness, buttons may be cured for Tc min. Condition the vulcanized sheets/buttons for 16 h to 96 h at a standard laboratory temperature and, if possible, at a standard laboratory humidity as defined in ISO Measure the stress-strain properties in accordance with ISO Evaluation of Shore hardness of vulcanized test mixes Use vulcanized sheets for the evaluation of tensile stress-strain properties. Measure the Shore hardness using durometers with the A scale for rubbers in the normal hardness range in accordance with ISO Test report The test report shall include the following: a) a reference to this International Standard; b) all details necessary for the identification of the sample; c) the method used for the acetone extract determination (method A or method B of ISO 1407:2011); d) the reference materials used to prepare the test mix; e) the ambient conditions in the laboratory during preparation of the test mix; f) the type of curemeter used, the defined time at which MH was measured and the amplitude of oscillation used for the curemeter test, as defined in Clause 6; g) any unusual features noted during the determination; h) details of any operation not included in this International Standard or in the International Standards to which reference is made, as well as of any operation regarded as optional; i) the results and the units in which they have been expressed; j) the date of the test. ISO 2012 All rights reserved 5

10 Bibliography [1] ISO 11235, Rubber compounding ingredients Sulfenamide accelerators Test methods 6 ISO 2012 All rights reserved