1、October 2009DEUTSCHE NORM English price group 9No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 83.080.01!$ZBB“1553131w
2、ww.din.deDDIN EN ISO 22088-5Plastics Determination of resistance to environmental stress cracking (ESC) Part 5: Constant tensile deformation method (ISO 22088-5:2006)English version of DIN EN ISO 22088-5:2009-10Kunststoffe Bestimmung der Bestndigkeit gegen umgebungsbedingte Spannungsrissbildung (ESC
3、) Teil 5: Verfahren mit konstanter Zugverformung (ISO 22088-5:2006)Englische Fassung DIN EN ISO 22088-5:2009-10www.beuth.deDocument comprises 14 pagesDIN EN ISO 22088-5:2009-10 2 National foreword This standard has been prepared by Technical Committee ISO/TC 61 “Plastics” (Secretariat: ANSI, USA) in
4、 collaboration with Technical Committee CEN/TC 249 “Plastics” (Secretariat: NBN, Belgium). The responsible German body involved in its preparation was the Normenausschuss Kunststoffe (Plastics Standards Committee), Technical Committee NA 054-01-04 AA Verhalten gegen Umgebungseinflsse. The DIN Standa
5、rd corresponding to the International Standard referred to in clause 2 of the EN ISO are as follows: ISO 293 DIN EN ISO 293 ISO 294-1 DIN EN ISO 294-1 ISO 527-2 DIN EN ISO 527-2 ISO 2818 DIN EN ISO 2818 ng parts, under the general title Plastics Determination of resistance to environmental stress cr
6、acking (ESC): Part 1: General guidance Part 2: Constant tensile load method Part 3: Bent strip method Part 4: Ball or pin impression method Part 5: Constant tensile deformation method Part 6: Slow strain rate method National Annex NA (informative) Bibliography DIN EN ISO 293, Plastics Compression mo
7、ulding of test specimens of thermoplastic materials DIN EN ISO 294-1, Plastics Injection moulding of test specimens of thermoplastic materials Part 1: General principles, and moulding of multipurpose and bar test specimens DIN EN ISO 527-2, Plastics Determination of tensile properties Part 2: Test c
8、onditions for moulding and extrusion plastics DIN EN ISO 2818, Plastics Preparation of test specimens by machining DIN EN ISO 22088 consists of the followiEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 22088-5 June 2009 ICS 83.080.01 English Version Plastics - Determination of resistance t
9、o environmental stress cracking (ESC) - Part 5: Constant tensile deformation method (ISO 22088-5:2006) Plastiques - Dtermination de la fissuration sous contrainte dans un environnement donn (ESC) - Partie 5: Mthode de dformation en traction constante (ISO 22088-5:2006) Kunststoffe - Bestimmung der B
10、estndigkeit gegen umgebungsbedingte Spannungsrissbildung (ESC) - Teil 5: Verfahren mit konstanter Zugverformung (ISO 22088-5:2006) This European Standard was approved by CEN on 23 May 2009. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for g
11、iving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN Management Centre or to any CEN member. This European Standard exists in three official
12、versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Bel
13、gium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FO
14、R STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2009 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 22088-5:2009: EContents 2 DIN EN ISO 2208
15、8-5:2009-10 EN ISO 22088-5:2009 (E) Page Foreword .3 1 Scope4 2 Normative references4 3 Terms and definitions .5 4 Principle .6 5 Apparatus.7 6 Conditioning and test conditions 8 6.1 Conditioning 8 6.2 Test temperature .8 6.3 Test medium 8 7 Test specimens8 7.1 Shape and dimensions .8 7.2 Number .8
16、7.3 Preparation.9 8 Test stress9 9 Procedure.10 10 Expression of results10 11 Precision 10 12 Test report11 Bibliography12 Foreword 3 EN ISO 22088-5:2009 (E) DIN EN ISO 22088-5:2009-10 The text of ISO 22088-5:2006 has been prepared by Technical Committee ISO/TC 61 “Plastics” of the International Org
17、anization for Standardization (ISO) and has been taken over as EN ISO 22088-5:2009 by Technical Committee CEN/TC 249 “Plastics” the secretariat of which is held by NBN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorseme
18、nt, at the latest by December 2009, and conflicting national standards shall be withdrawn at the latest by December 2009. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent ights. CEN and/or CENELEC shall not be held responsible for identify
19、ing any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following ountries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece,
20、Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 22088-5:2006 has been approved by CEN as a EN ISO 22088-5:2009 without any
21、 modification. 1 Scope This part of ISO 22088 specifies a method for the determination of the environmental stress cracking (ESC) behaviour of thermoplastics when they are subjected to a constant tensile deformation in the presence of a chemical medium. It is applicable to test specimens prepared by
22、 moulding and/or machining and can be used for the assessment of the ESC behaviour of plastic materials exposed to different environments, as well as for the determination of the ESC behaviour of different plastic materials exposed to a specific environment. This is essentially a ranking test and is
23、 not intended to provide data to be used for design or performance prediction. NOTE Alternative methods for the determination of environmental stress cracking by means of a constant-strain test are specified in ISO 22088-3 and ISO 22088-4. A method for the determination of environmental stress crack
24、ing by means of a constant tensile load is specified in ISO 22088-2. 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 do
25、cument (including any amendments) applies. ISO 293, Plastics Compression moulding of test specimens of thermoplastic materials ISO 294-1, Plastics Injection moulding of test specimens of thermoplastic materials Part 1: General principles, and moulding of multipurpose and bar test specimens ISO 294-5
26、, Plastics Injection moulding of test specimens of thermoplastic materials Part 5: Preparation of standard specimens for investigating anisotropy ISO 527-2, Plastics Determination of tensile properties Part 2: Test conditions for moulding and extrusion plastics ISO 2818, Plastics Preparation of test
27、 specimens by machining ISO 22088-1:2006, Plastics Determination of resistance to environmental stress cracking (ESC) Part 1: General guidance 4 DIN EN ISO 22088-5:2009-10 EN ISO 22088-5:2009 (E) 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.
28、1 stress relaxation time-dependent decrease in stress 3.2 initial stress stress occurring when a specimen is first subjected to a constant strain 3.3 stress ratio ratio of the initial stress to the stress after a certain amount of time 3.4 stress relaxation curve curve obtained by plotting the stres
29、s ratio as ordinate and the logarithm of time as abscissa 3.5 critical stress maximum stress that can be applied without altering the stress relaxation curve NOTE The shape of a stress relaxation curve depends upon the strain applied (see Figure 1). Below a certain strain, further reduction of the s
30、train does not change the curve. The stress at this particular strain is defined as the critical stress. Key t time 0initial stress stress at time t /0stress ratio NOTE 1 The numbers 1 to 5 indicate the order in which the tests were performed. NOTE 2 The strains applied to the specimens were as foll
31、ows: curve 2 curve 1 curve 3 curve 4 curve 5. NOTE 3 The stress applied in curve 4 corresponds to the critical stress. Figure 1 Determination of critical stress 5 EN ISO 22088-5:2009 (E) DIN EN ISO 22088-5:2009-10 4 Principle A specimen held at a constant deformation is exposed to a chosen chemical
32、environment at a selected test temperature. The deformation is produced by an initial tensile force that is lower than that at the yield point (or that at the breaking point if the material does not exhibit a yield point) and is held in place by a device such as a worm-gear. The environmental stress
33、 cracking behaviour of the test specimen is evaluated by comparing the critical stress in a selected chemical environment with the critical stress for the same material in air. Comparing the shape of the stress relaxation curve obtained after an initial stress is applied in a selected chemical envir
34、onment with that of the stress relaxation curve obtained when the same initial stress is applied in air is also an essential part of the evaluation. The critical stress may be used as an index for ESC. For example, if the critical stress obtained in a particular chemical environment is less than tha
35、t in air, the material is regarded as being affected by the chemical environment. In addition, it is possible to determine quantitatively the degree of ESC as the difference between the critical stress in air and that in the chemical environment. The shape of the stress relaxation curve may also be
36、used as a qualitative index of ESC. In Figure 2, curve A is the reference curve in air. Curve B deviates downwards from curve A due to a slight swelling effect caused by the chemical used for this test. Plastics in this state may be safely used when exposed to this chemical if the maximum allowed st
37、ress is relatively low. Curve C shows how the molecular structure of a polymer can be weakened by continuous ESC. Curve D indicates how the stress can be reduced very significantly by ESC. Plastics which give curves like C and D are not suitable for use in the chemical environment concerned. Key t t
38、ime 0initial stress stress at time t /0stress ratio Figure 2 Classification of stress relaxation curves 6 DIN EN ISO 22088-5:2009-10 EN ISO 22088-5:2009 (E) 5 Apparatus 5.1 Test device, allowing test specimens to be held at a constant tensile deformation while exposed to a chemical medium (Figure 3
39、is a schematic diagram of a suitable apparatus). A strain gauge with an accuracy of 1% can be used to measure the tensile load. The parts of the device which come into contact with the chemical medium shall be made of, or coated with, an inert material, such as stainless steel, polytetrafluoroethyle
40、ne or another suitable material. Care shall be taken that the specimens are subjected only to forces parallel to their longitudinal axis, and not to bending or twisting forces. Key 1 worm-gear 5 clamp 2 screw 6 glass container 3 load cell 7 test specimen 4 cover 8 chemical medium Figure 3 One type o
41、f apparatus for stress relaxation testing 7 EN ISO 22088-5:2009 (E) DIN EN ISO 22088-5:2009-10 5.2 Temperature-controlled bath or oven, allowing the containers to be maintained at (23 2) C or at a higher test temperature up to 100 C to within 2 C (see Clause 6). 5.3 Containers, allowing the test ass
42、embly to be immersed completely in a test medium, with a cover that can be sealed for chemicals which are volatile at the immersion temperature. Materials used for containers shall not interact with the immersion liquid. 5.4 Equipment for the preparation of test specimens by moulding (see ISO 293, I
43、SO 294-1 and ISO 294-5), machining (see ISO 2818) or die cutting. 6 Conditioning and test conditions 6.1 Conditioning Unless otherwise specified in the relevant material standard or agreed upon between the interested parties, the test specimen shall be conditioned before testing for at least 24 h at
44、 (23 2) C and (50 10) % relative humidity. 6.2 Test temperature The preferred test temperatures are (23 2) C and (55 2) C. If required, other temperatures may be used, preferably selected from the following: (40 2) C, (70 2) C, (85 2) C, (100 2) C, or as agreed upon by the interested parties. 6.3 Te
45、st medium See ISO 22088-1:2006, 7.3 7 Test specimens 7.1 Shape and dimensions The shape and dimensions of the test specimen shall be as given in Figure 4. This test specimen is the half-size type 1BA test specimen specified in ISO 527-2. The preferred thickness is (2 0,2) mm, but when the test speci
46、mens are prepared from finished products the thickness may be that of the product. Alternatively, a type 1BA specimen 3 mm to 4 mm thick may be used. 7.2 Number The number of test specimens required for one set of test conditions is 10, i.e. 5 specimens in test medium and in air, respectively. NOTE
47、If the material is thought to be anisotropic, two sets of specimens shall be used, one set is perpendicular to the principal direction and the other is in the same as the principal direction. 8 DIN EN ISO 22088-5:2009-10 EN ISO 22088-5:2009 (E) Key l3overall length: 75 mm b2width at ends: (10 0,5) m
48、m l1length of narrow, parallel-sided portion: (30 0,5) mm b1width of narrow, parallel-sided portion: (5 0,5) mm r radius, minimum: 30 mm h thickness: preferably (2 0,2) mm l0distance between gauge marks: 25 mm l2initial distance between grips: 57 mm Figure 4 ISO 527-2 type 1BA specimen (type 1B scal
49、ed down 2:1) 7.3 Preparation The specimens shall be prepared, taking into consideration the presence or absence of anisotropy, in accordance with the relevant International Standard. If no procedure for specimen preparation is given, specimens shall be machined from sheet or from finished products by the methods specified in ISO 2818. If sheets are prepared from moulding materials, they shall be moulded in accordance with the relevant material specification or a
