1、June 2015Translation by DIN-Sprachendienst.English price group 11No part of this translation 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
2、.060!%B4“2319117www.din.deDDIN ISO 132Rubber, vulcanized or thermoplastic Determination of flex cracking and crack growth (De Mattia)(ISO 132:2011),English translation of DIN ISO 132:2015-06Elastomere oder thermoplastische Elastomere Bestimmung der Rissbildung und Risswachstum (De Mattia) (ISO 132:2
3、011),Englische bersetzung von DIN ISO 132:2015-06Caoutchouc, vulcanis ou thermoplastique Dtermination de la rsistance au dveloppement dune craquelure (De Mattia)(ISO 132:2011),Traduction anglaise de DIN ISO 132:2015-06SupersedesDIN ISO 132:2008-07www.beuth.deIn case of doubt, the German-language ori
4、ginal shall be considered authoritative.Document comprises 20 pages04.15 A comma is used as the decimal marker. Contents Page National foreword .3 National Annex NA (informative) Bibliography .4 Introduction .5 1 Scope .6 2 Normative references .6 3 Apparatus 6 4 Calibration .7 5 Test pieces 7 5.1 S
5、hape, dimensions and preparation 7 5.2 Preparation of test pieces for crack growth measurement 8 5.3 Time interval between vulcanization and testing . 10 5.4 Conditioning. 10 5.5 Number of test pieces . 10 6 Test conditions 10 6.1 Temperature . 10 6.2 Humidity . 10 7 Procedure . 10 7.1 General . 10
6、7.2 Determination of flex cracking . 11 7.3 Determination of crack growth. 11 8 Expression of results 11 8.1 Determination of flex cracking . 11 8.2 Determination of crack growth. 12 9 Precision . 12 10 Test report 12 Annex A (normative) Calibration schedule 14 Annex B (informative) Precision 16 Bib
7、liography . 20 2DIN ISO 132:2015-063DIN ISO 132:2015-06National foreword The text of ISO 132:2011 Rubber, vulcanized or thermoplastic Determination of flex cracking and crack growth (De Mattia) has been adopted in this standard without any modification. This document (ISO 132:2011) has been prepared
8、 by Technical Committee ISO/TC 45 “Rubber and rubber products” (Secretariat: DSM, Malaysia), Subcommittee SC 2 “Testing and analysis” (Secretariat: SIS, Sweden). The responsible German body involved in its preparation was the DIN-Normenausschuss Material-prfung (DIN Standards Committee Materials Tes
9、ting), Working Committee NA 062-04-34 AA Prfung der physikalischen Eigenschaften von Kautschuk und Elastomeren. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. DIN and/or DKE shall not be held responsible for identifying any or al
10、l such patent rights. The DIN Standard corresponding to the International Standard referred to in this document is as follows: ISO 23529 DIN ISO 23529 Amendments This standard differs from DIN ISO 132:2008-07 as follows: a) normative references have been updated; b) Annex B (informative) “Precision”
11、 has been added; c) Annex A (normative) “Calibration schedule” has been added. Previous editions DIN 53522-1: 1960-01, 1979-01 DIN 53522-2: 1960-02, 1979-01 DIN 53522-3: 1960-01, 1979-01 DIN ISO 132: 2004-05, 2008-07 National Annex NA (informative) Bibliography DIN ISO 23529, Rubber General procedur
12、es for preparing and conditioning test pieces for physical test methods 4DIN ISO 132:2015-06Rubber, vulcanized or thermoplastic Determination of flex cracking and crack growth (De Mattia) Introduction Repeated bending or flexing of a rubber causes cracks to develop in that part of the surface where
13、tension stress is set up during flexing or, if this part of the surface contains a crack, causes this crack to extend in a direction perpendicular to the stress. Certain soft vulcanizates, for instance those prepared from styrene-butadiene rubber, show marked resistance to crack initiation, but it i
14、s possible for these vulcanizates to have a low resistance to growth (propagation) of cracks. It is important, therefore, to measure both the resistance to crack initiation by flexing and the resistance to crack propagation. The method is suitable for rubbers that have reasonably stable stress-strai
15、n properties, at least after a period of cycling, and do not show undue stress softening or set, or highly viscous behaviour. The results obtained for some thermoplastic rubbers should be treated with caution if the elongation at yield is below, or close to, the maximum strain imposed during the tes
16、t. 5DIN ISO 132:2015-06WARNING Persons using this International Standard should be familiar with normal laboratory practice. This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and
17、 health practices and to ensure compliance with any national regulatory conditions. IMPORTANT Certain procedures specified in this International Standard might involve the use or generation of substances, or the generation of waste, that could constitute a local environmental hazard. Reference shoul
18、d be made to appropriate documentation on safe handling and disposal after use. 1 Scope This International Standard specifies a method of test intended for use in comparing the resistance of vulcanized or thermoplastic rubbers to the formation and growth of cracks, when subjected to repeated flexing
19、 on the De Mattia type machine. For determination of crack growth, an artificial cut is made in the test piece to initiate cut growth. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applie
20、s. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 18899:2004, Rubber Guide to the calibration of test equipment ISO 23529, Rubber General procedures for preparing and conditioning test pieces for physical test methods 3 Apparatus 3.1 De
21、Mattia type machine, the essential features of which are as follows: The machine has stationary parts, provided with grips for holding one end of each of the test pieces in a fixed position, and similar but reciprocating parts for holding the other end of each of the test pieces. The travel is mm an
22、d is such that the maximum distance between each set of opposing grips is 0,50571075 mm (see Figure 1). The reciprocating parts are so arranged that their motion is straight and in the direction of, and in the same plane as, the common centreline of each opposing pair of grips. The planes of the gri
23、pping surfaces of each opposing pair of grips remain parallel throughout the motion. The eccentric which actuates the reciprocating parts is driven by a constant-speed motor to give 5,00 Hz 0,17 Hz, with sufficient power to flex at least six, and preferably 12, test pieces at one test. The grips hol
24、d the test pieces firmly, without undue compression, and enable individual adjustment to be made to the test pieces to ensure accurate insertion. 6DIN ISO 132:2015-06It is useful to arrange the test pieces in two equal groups, so that one group is being flexed while the other group is being straight
25、ened, thus reducing the vibration in the machine. For testing at elevated or subnormal temperatures, the machine can be enclosed in a chamber with temperature control near the centre of the test piece to 2 C, if necessary, by using an air circulator. 3.2 Piercing tool and suitable jig, for piercing
26、the test pieces (see 5.2). Dimensions in millimetres Key 1 upper grip 2 lower grip aTravel. Figure 1 De Mattia type machine 4 Calibration The requirements for calibration of the test apparatus are given in Annex A. 5 Test pieces 5.1 Shape, dimensions and preparation Each test piece shall be a strip
27、with a moulded groove. The strips can be moulded individually in a multiple-cavity mould, as shown in Figure 2, or can be cut from a wide slab having a moulded groove. The groove in the test piece shall have a smooth surface and be free from irregularities from which cracks can start prematurely. Th
28、e groove shall be moulded into the test piece or slab by a half-round ridge in the centre of the cavity. 7DIN ISO 132:2015-06The half-round ridge shall have a radius of 2,38 mm 0,03 mm. The moulded groove shall be perpendicular to the direction of mill grain. Results can be compared only between tes
29、t pieces having thicknesses, measured close to the groove, which are within the tolerances, because the results of the test are dependent upon the thickness of the test piece. If finished products are to be tested, test pieces without a groove can be used. They shall be prepared in accordance with I
30、SO 23529. Cracks shall not be assessed on surfaces that have been cut or buffed. The use of test pieces cut and/or buffed from finished products shall be stated in the test report. Dimensions in millimetres Figure 2 Form for moulding test piece 5.2 Preparation of test pieces for crack growth measure
31、ment Each test piece shall be prepared by piercing the bottom of the groove at a point equidistant from the sides, using a suitable jig. The piercing tool shall conform to the dimensions given in Figure 3. The piercing tool shall be maintained perpendicular to both the transverse and longitudinal ax
32、es, and the cut accomplished by a single insertion and withdrawal of the tool. The cut shall be parallel to the longitudinal axis of the groove. Lubrication with water containing a suitable wetting agent can be used. A suitable jig shall be provided to hold the piercing tool; the exact details are n
33、ot specified but the principles of operation shall be as follows: The test piece shall be held flat in a solid support. The piercing tool shall be normal to the support and placed centrally with respect to the groove in the test piece, with the cutting edge of the piercing tool parallel to the axis
34、of the groove. Means shall be provided for passing the piercing tool through the entire thickness of the rubber, and the support shall have a hole of a size just sufficient to permit the piercing tool to project through the base of the test piece to not less than 2,5 mm and not more than 3 mm. 8DIN
35、ISO 132:2015-06Dimensions in millimetres Key 1 test piece Figure 3 Piercing tool 9DIN ISO 132:2015-065.3 Time interval between vulcanization and testing For all test purposes, the minimum time between vulcanization and testing shall be 16 h in accordance with ISO 23529. For non-product tests, the ma
36、ximum time between vulcanization and testing shall be 4 weeks and, for evaluations intended to be comparable, the tests shall, as far as possible, be carried out after the same time interval. As far as possible, samples and test pieces shall be kept away from exposure to light. 5.4 Conditioning For
37、tests under standard laboratory conditions (see Clause 6), individually moulded test pieces shall be conditioned under the test conditions for a period of time in accordance with ISO 23529 immediately before testing. Slab samples shall be similarly conditioned before the test pieces are cut. These t
38、est pieces can be either tested immediately or kept at the test temperature until tested. For tests at other temperatures (see Clause 6), after the conditioning period specified above the test pieces shall be brought to the test temperature by keeping in a chamber at this temperature for 3 h, then t
39、ested immediately (see ISO 23529). The same test temperature shall be used throughout any test or series of tests intended to be comparable. 5.5 Number of test pieces At least three, and preferably six, test pieces from each rubber compound shall be tested. If comparison is required between differen
40、t compounds, ensure that test pieces of each compound are mounted at the same time on the same test machine. 6 Test conditions 6.1 Temperature Tests are normally performed at a standard laboratory temperature as defined in ISO 23529, although elevated or subnormal temperatures can often be used to a
41、dvantage. In the latter case, the test temperature shall be selected from ISO 23529. 6.2 Humidity With compounds where the results are known to be sensitive to humidity, the test shall be carried out under standard laboratory conditions (temperature and humidity) as defined in ISO 23529. NOTE An inf
42、luence of humidity has been observed with fluororubbers, polyurethane rubbers and other rubbers containing hydrophilic fillers. 7 Procedure 7.1 General The presence of significant amounts of ozone in the laboratory atmosphere affects the results. Periodic checks are advised to ensure that the ambien
43、t ozone concentration is preferably less than 1 part by volume per 100 million parts of air. 10DIN ISO 132:2015-06The test shall not be made in a room which contains any apparatus that generates ozone, such as a fluorescent lamp, or which for any reason has an atmosphere with an ozone content above
44、that of normal indoor air. The motor used to drive the test machine shall be of a type that does not generate ozone. 7.2 Determination of flex cracking Separate the pairs of grips to their maximum extent, and insert the test pieces so that they are flat and not under tension, with the groove in each
45、 test piece midway between the two grips in which that test piece is held, and on the outside of the angle made by the test piece when it is bent. Ensure that the test pieces are positioned at exactly 90 to the grips. Start the machine and continue the test with frequent inspections until the first
46、small sign of cracking is detected on each test piece. Record the number of flexing cycles at this point, restart the machine and stop it after intervals of, for instance, 1 h, 2 h, 4 h, 8 h, 24 h, 48 h, 72 h and 96 h. As an alternative, stop it after intervals in which the number of flexing cycles
47、is increased in geometric progression, a suitable ratio being 1,5 on each occasion. Carry out each inspection of the test pieces with the test pieces fixed in place but the grips separated to a distance of 65 mm. Cracks occurring at the edge of the test piece shall be ignored. Grade the severity of
48、cracking by comparison with a standard scale, as specified in 8.1. Do not run the test pieces to complete rupture, but to a given grade of cracking. 7.3 Determination of crack growth Measure the initial length L of the cut, preferably using a low-power magnifying glass. Insert the test pieces as des
49、cribed in 7.2, first paragraph. Start the machine and stop it at frequent intervals to measure the length of the cut, for example after 1, 3 and 5 kilocycles and at such further or intermediate intervals as appear necessary. At each inspection, separate the grips to a distance of 65 mm and measure the length of the cut, preferably using a low-power magnifying glass. Do not run the test pieces to complete rupture, but to a specified crack growth in accordance with 8.2.
