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1、 Reference number ISO 22088-3:2006(E) ISO 2006 INTERNATIONAL STANDARD ISO 22088-3 First edition 2006-08-15 Plastics Determination of resistance to environmental stress cracking (ESC) Part 3: Bent strip method Plastiques Dtermination de la fissuration sous contrainte dans un environnement donn (ESC)
2、Partie 3: Mthode de lprouvette courbe Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 07:46:43 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22088
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6、low. ISO 2006 All rights reserved. Unless otherwise specified, 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
7、 in the country of the requester. ISO copyright office 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 2006 All rights reserved Copyright International Organization for Standardization Provided by
8、IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 07:46:43 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22088-3:2006(E) ISO 2006 All rights reserved iii Contents Page Foreword iv 1 Scope . 1 2 Normative references. 1
9、 3 Terms and definitions. 2 4 Principle. 4 5 Apparatus 4 6 Test specimens. 5 6.1 Form and dimensions. 5 6.2 Preparation 5 6.3 Number 5 7 Conditioning and test conditions 5 7.1 Conditioning 5 7.2 Test temperature. 5 7.3 Test medium 5 8 Procedure 5 8.1 Precautions . 5 8.2 Mounting the test specimens 5
10、 8.3 Contact with the test environment 6 8.4 Storage in contact with the test environment 6 8.5 Determination of the indicative property 7 9 Expression of results . 7 9.1 Calculation. 7 9.2 Graphical evaluation. 7 10 Precision 8 11 Test report . 9 Bibliography. 10 Copyright International Organizatio
11、n for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 07:46:43 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22088-3:2006(E) iv ISO 2006 All rights reserved Foreword ISO (the Internationa
12、l 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 es
13、tablished 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 standardi
14、zation. 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 vot
15、ing. 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. ISO shall not be held responsible for identifying any or all suc
16、h patent rights. ISO 22088-3 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 6, Ageing, chemical and environmental resistance. It cancels and replaces ISO 4599:1986, which has been technically revised. ISO 22088 consists of the following parts, under the general title Plasti
17、cs Determination of resistance to environmental stress cracking (ESC): Part 1: General guidance Part 2: Constant tensile load method (replacement of ISO 6252:1992) Part 3: Bent strip method (replacement of ISO 4599:1986) Part 4: Ball or pin impression method (replacement of ISO 4600:1992) Part 5: Co
18、nstant tensile deformation method (new test method) Part 6: Slow strain rate method (new test method) Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 07:46:43 MDTNo reproduction
19、or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD ISO 22088-3:2006(E) ISO 2006 All rights reserved 1 Plastics Determination of resistance to environmental stress cracking (ESC) Part 3: Bent strip method 1 Scope This part of ISO 22088 specifies a method for the determinati
20、on of the environmental stress cracking (ESC) resistance of thermoplastics when they are subjected to a fixed flexural strain in the presence of chemical agents. ESC is indicated by the change of a suitably chosen indicative property of specimens that have been strained for a defined time in the env
21、ironment. The method of test is suitable for determining the resistance of sheets and of flat test specimens, especially the sensitivity of localized surface regions of specimens, to ESC. The bent strip method is suitable for the determination of ESC caused by gases and liquids as well as solids con
22、taining migrating substances (e.g. polymeric adhesives and materials containing plasticizers) in contact with a specific polymer. Preferably, this method is used to determine the ESC resistance of rigid plastics that exhibit only moderate stress relaxation during the time of the test. This is essent
23、ially a ranking test and is not intended to provide data to be used for design or performance prediction. NOTE For a constant-strain test, refer to ISO 22088-5. For a constant-load test, refer to ISO 22088-2. 2 Normative references The following referenced documents are indispensable for the applica
24、tion 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 178, Plastics Determination of flexural properties ISO 179-1, Plastics Determination of Charpy impact properties
25、Part 1: Non-instrumented impact test ISO 527-2, Plastics Determination of tensile properties Part 2: Test conditions for moulding and extrusion plastics ISO 2818, Plastics Preparation of test specimens by machining ISO 22088-1:2006, Plastics Determination of resistance to environmental stress cracki
26、ng (ESC) Part 1: General guidance Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 07:46:43 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22088-3:2
27、006(E) 2 ISO 2006 All rights reserved 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 flexural strain x nominal value of the strain in the tensile surface of a flat test specimen of thickness h, bent over the segment of a circle with radius r
28、, calculated from the equation x 2 h rh = + NOTE See Figure 1. Key 1 clamps 2 test specimen: tensile surface in contact with test medium compressive surface in contact with form 3 form h thickness of test specimen r radius of form x nominal strain in tensile surface Figure 1 Test specimen with defin
29、ed strain in the tensile surface 3.2 strain value one of a series of strain levels applied to successive test specimens during exposure 3.3 strain series a number of strain values, including zero NOTE 1 Normally, the results of the mechanical test on test specimens with zero applied strain are equiv
30、alent whether determined in air or in a chemical test medium. If the property measured after exposure to the test medium at zero strain is different from that after exposure in air at zero strain, embrittlement or softening by the test medium should be suspected. In some cases, relief of stresses im
31、parted during specimen preparation such as by injection-moulding or machining can contribute to differences in results for stress cracking in air and another test medium. NOTE 2 It is recommended that the test specimen for zero strain be clamped on to a flat form to prevent warping due to the effect
32、 of the test medium. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 07:46:43 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22088-3:2006(E) ISO 20
33、06 All rights reserved 3 3.4 failure strain F lowest strain in the strain series at which failure is observed 3.5 indicative property property observed to determine failure using a criterion such as those given in Table 1 3.6 ESC index ratio of the value of failure strain determined in the test medi
34、um to that determined in the reference medium (usually air) for the same time of exposure Table 1 Suggested indicative properties and failure criteria (see Note 1) Indicative property International Standard Failure criterion Designation State of surface (assessed by visual examination) Cracks or cra
35、zes around the tensile surface edges A1 State of surface (assessed by visual examination) Cracks or crazes in the tensile surface A2 State of surface (assessed by visual examination) Any other observation, e.g. change in colour or appearance A3 Tensile stress at break or tensile stress at yield ISO
36、527-2 80 % of the value obtained on unstrained unexposed test specimens (see Note 2) B1 Flexural stress at maximum load ISO 178 80 % of the value obtained on unstrained unexposed test specimens (see Note 2) B2 Percentage tensile strain at break or tensile strain at yield ISO 527-2 50 % of the value
37、obtained on unstrained unexposed test specimens (see Note 2) B3 Charpy impact strength, unnotched ISO 179-1 50 % of the value obtained on unstrained unexposed test specimens (see Note 3) B4 Tensile impact strength See Note 4 50 % of the value obtained on unstrained unexposed test specimens B5 Any ot
38、her property agreed upon To be agreed B6 NOTE 1 The state of the test specimens, the indicative property and the failure criterion shall be selected with a view to the practical service conditions. NOTE 2 If the material is thought to be anisotropic, two sets of specimens shall be used, one set cut
39、at right angles to the other in two of the principal directions of orientation. This applies only to specimens having the appropriate dimensions. NOTE 3 Data comparisons will only be valid if the failure mode is the same in all cases. NOTE 4 This question is under study. Copyright International Orga
40、nization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 07:46:43 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22088-3:2006(E) 4 ISO 2006 All rights reserved 4 Principle A test speci
41、men suitable for the determination of the indicative property is clamped with one of its faces over a form of constant radius and brought into contact with the test environment. Due to the influence of the environment in the presence of strain, crazes may be generated which with time sometimes devel
42、op into visible cracks. By using a series of forms with decreasing radii, a series of test specimens that have increasing strains in the outer surface can be tested. After an agreed duration of contact with the test environment, the test specimens are visually observed, unclamped and assessed by mec
43、hanical or other testing. The failure strain that corresponds to the failure criterion is obtained directly from the tabulated values or graphically. The maximum strain must be less than the strain at yield. NOTE 1 The failure criterion is also commonly expressed in terms of the ESC index. NOTE 2 Th
44、e failure strains for different indicative properties may be different. 5 Apparatus 5.1 Forms, made from chemical-resistant material either by machining or by bending metal sheet (for example, stainless-steel sheet). For test specimens 2 mm to 4 mm thick, radii of curvature of 30 mm to 500 mm are su
45、itable. The form shall have roughly the same length as the test specimen. To increase the contact between the test specimen and the test medium, the forms may be perforated. NOTE The radius r of the segment of a circular arc of height h and chord length l is given by the equation 2 82 lh r h =+ 5.2
46、Clamps, made from chemical-resistant material. The clamps shall be designed so that they hold the test specimen lightly. The contact between the test specimen and the form need not extend to the clamps, but shall extend over that length of test specimen which will be most highly stressed in the subs
47、equent mechanical test. In no case shall the contact region (measured in the direction of the length of the test specimen) be less than 10 times the specimen thickness. 5.3 Vessels, such as carefully cleaned glass containers with well fitting lids, suitable for holding the mounted test specimens and
48、 the test medium. Other types of vessel may be used provided there is no interaction between the material of which the vessel is made and the specimens or test medium. When the contact between the test specimens and the test medium takes place under other conditions, such as exposure to a vapour or a water spray, this fact shall be reported. 5.4 Micrometer, capable of determining the thickness of the test specimens to within 0,01 mm. 5.5 Apparatus for determining the indicative proper