1、December 2014Translation by DIN-Sprachendienst.English price group 9No 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
2、 83.060!%Zo“2275576www.din.deDDIN ISO 27588Rubber, vulcanized or thermoplastic Determination of dead-load hardness using the very low rubberhardness (VLRH) scale (ISO 27588:2012),English translation of DIN ISO 27588:2014-12Elastomere oder thermoplastische Elastomere Bestimmung der Gewichtbelastungs-
3、Hrte mittels der Skala der sehr niedrigenGummihrte (VLRH) (ISO 27588:2012),Englische bersetzung von DIN ISO 27588:2014-12Caoutchouc vulcanis ou thermoplastique Dtermination de la duret sous charge constante au moyen de lchelle de trs faibleduret (VLRH) (ISO 27588:2012),Traduction anglaise de DIN ISO
4、 27588:2014-12SupersedesDIN ISO 27588:2010-05www.beuth.deIn case of doubt, the German-language original shall be considered authoritative.Document comprises 14 pages12.14 A comma is used as the decimal marker. Contents Seite National foreword .3 National Annex NA (informative) Bibliography .4 Introd
5、uction .5 1 Scope .6 2 Normative references .6 3 Principle .6 4 Apparatus 6 5 Calibration .7 6 Test pieces 7 7 Time interval between forming the test pieces and testing .7 8 Conditioning7 9 Temperature of test 7 10 Procedure 8 11 Test report .8 Annex A (normative) Relationship between indentation de
6、pth and hardness, and derivation of the VLRH scale .9 Annex B (normative) Calibration schedule 12 Bibliography . 14 2DIN ISO 27588:2014-12National foreword The text of this standard (ISO 27588:2012) has been prepared by Technical Committee ISO/TC 45 “Rubber and rubber products”, Subcommittee SC 2 “T
7、esting and analysis” (Secretariat: JISC, Japan). The responsible German body involved in its preparation was the DIN-Normenausschuss Materialprfung (DIN Standards Committee Materials Testing), Working Committee NA 062-04-34 AA Prfung der physika-lischen Eigenschaften von Kautschuk und Elastomeren. A
8、ttention 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 all such patent rights. Symbols and abbreviations The following symbols and abbreviations are used in this document
9、: Abbreviation/ Symbol Denotation VLRH Very Low Rubber Hardness (VLRH) IRHD International Rubber Hardness Degree (IRHD) IRHD N International Rubber Hardness Degree Normal (IRHD N) IRHD L International Rubber Hardness Degree Low (IRHD L) D Depth of penetration HcurvedHardness of test piece with curve
10、d surface HflatHardness of test piece with flat surface The DIN Standards corresponding to the International Standards referred to in this document are as follows: ISO 48 DIN ISO 48 ISO 7619-1 DIN ISO 7619-1 ISO 18898 DIN ISO 18898 ISO 23529 DIN ISO 23529 Amendments This standard differs from DIN IS
11、O 27588:2010-05 as follows: a) Annex B (normative) “Calibration schedule” has been added; b) the standard has been editorially revised. Previous editions DIN ISO 27588: 2010-05 3DIN ISO 27588:2014-12National Annex NA (informative) Bibliography DIN ISO 48, Rubber, vulcanized or thermoplastic Determin
12、ation of hardness (hardness between 10 IRHD and 100 IRHD) DIN ISO 7619-1, Rubber, vulcanized or thermoplastic Determination of indentation hardness Part 1: Durometer method (Shore hardness) DIN ISO 18898, Rubber Calibration and verification of hardness testers DIN ISO 23529, Rubber General procedure
13、s for preparing and conditioning test pieces for physical test methods 4DIN ISO 27588:2014-12IntroductionThe hardness test specified in this International Standard is intended as a more discriminating alternative to the international rubber hardness degrees scale (ISO 48) for rubbers below 35 IRHD.
14、A durometer method for soft rubbers is described in ISO 7619-1 as the AO scale. Examples of applications are low-modulus bearings, soft roller coverings and printing rubbers.Figure 1 shows a comparison of the ranges of the IRHD N and IRHD L methods in ISO 48 with the VLRH scale of this International
15、 Standard.The methods differ primarily in the diameter of the indenting ball and the magnitude of the indenting force, these being chosen to suit the particular application.Figure 1 Comparison of the ranges of hardness measurement methods for rubberRubber, vulcanized or thermoplastic Determination o
16、f dead-load hardness using the very low rubber hardness (VLRH) scale 5DIN ISO 27588:2014-12WARNING 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 i
17、s the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditions.1 ScopeThis International Standard specifies a dead-load method for the determination of the hardness of very soft vulcanized or thermoplastic rubber
18、s using the very low rubber hardness (VLRH) scale.The relation between the depth of penetration and the VLRH scale is linear.2 Normative referencesThe following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For unda
19、ted references, the latest edition of the referenced document (including any amendments) applies.ISO 18898:2012, Rubber Calibration and verification of hardness testersISO 18899, Rubber Guide to the calibration of test equipmentISO 23529, Rubber General procedures for preparing and conditioning test
20、 pieces for physical test methods3 PrincipleThe hardness test consists of measuring the difference between the depths of indentation of a ball into the rubber under a small contact force and a large total force. From this difference, the hardness in “very low rubber hardness degrees” (VLRH) is obtai
21、ned using Table A.1 (see Annex A) or graphs based on this table or a scale, reading directly in very low rubber hardness degrees, calculated from the tables and fitted to the indentation-measuring instrument.4 ApparatusThe essential parts of the apparatus are as follows, the appropriate dimensions a
22、nd forces being shown in Table 1. Detailed information can be found in References 1 and 2.4.1 Vertically guided plunger, having a ball or spherical surface on the lower end, and means for supporting the plunger so that the spherical tip is kept slightly above the surface of the annular foot prior to
23、 applying the contact force.4.2 Means for applying a contact force and an additional indenting force to the plunger, making allowance for the mass of the plunger, including any fittings attached to it, and for the force of any spring acting on it, so that the forces actually transmitted through the
24、spherical end of the plunger are as specified.4.3 Means for measuring the increase in depth of indentation of the plunger caused by the indenting force, either in millimetres with a maximum uncertainty of 0,001 mm, or reading directly in VLRH with a resolution such that a reading to at least 0,5 VLR
25、H is possible.6DIN ISO 27588:2014-124.4 Flat annular foot, normal to the axis of the plunger and having a central hole for the passage of the plunger. The foot rests on the test piece and shall be rigidly connected to the indentation measurement device so that a measurement is made of the movement o
26、f the plunger relative to the foot (i.e. the top surface of the test piece), not relative to the surface supporting the test piece.If it is required that measurements be made on test pieces with a curved surface, a calibration has to be carried out. Tests need to be made on test pieces of the materi
27、al with both flat and curved surfaces. The hardness difference (Hcurved Hflat) which is found for the flat and the curved test pieces is used with opposite sign as correction of the hardness values obtained on test pieces of a similar material with a curved surface.4.5 Measuring table, as support fo
28、r the test piece. The measuring table shall be flat and normal to the axis of the plunger.Table 1 Nominal values and tolerances of forces and diametersForce on ballForce on foot mNContact mNIndenting mNTotal mN8,3 0,5 91,7 0,5 100,0 1,0 235 30Diameter mmBall Foot Hole2,50 0,01 6,0 0,5 3,0 0,15 Calib
29、rationThe requirements for calibration of the test apparatus are given in Annex B.6 Test piecesThe test pieces shall be prepared in accordance with ISO 23529.The test pieces shall have their upper and lower surfaces flat, smooth and parallel to one another.The standard test piece shall be a minimum
30、of 6 mm thick and shall be made up of one, two or three layers of rubber, the thinnest of which shall not be less than 2 mm. The lateral dimensions of the test piece shall be such that three or more measurements can be made at least 10 mm from each other and at least 3 mm from the edges of the test
31、piece.Test pieces of other dimensions or from finished products may be used but will usually produce results which differ from those obtained with standard test pieces.7 Time interval between forming the test pieces and testingThe time interval between forming the test pieces and testing shall be in
32、 accordance with ISO 23529.8 ConditioningThe test pieces shall be maintained at a standard laboratory temperature (see ISO 23529) for a minimum of 3 h immediately before testing.9 Temperature of testThe test shall be carried out at the same standard laboratory temperature as was used for the conditi
33、oning.7DIN ISO 27588:2014-1210 ProcedurePlace a test piece on the horizontal measuring table. Bring the foot into contact with the surface of the test piece. Press the plunger and indenting ball onto the rubber for 5 s, the force on the ball being the contact force.If the gauge is graduated in VLRH
34、degrees, adjust it to read 100 at the end of the 5 s period. Then apply the additional indenting force and maintain it for 30 s, when a direct reading of hardness in VLRH degrees is obtained.If the gauge is graduated in millimetres, note the differential indentation of the plunger caused by the addi
35、tional indenting force, applied for 30 s. Convert this to VLRH degrees by using Table A.1 or a graph constructed therefrom.Repeat the test to obtain measurements at three different locations on the test piece, observing the requirements for separation distances given in Clause 6. Take the median of
36、the three results as the result of the test.11 Test reportThe test report shall include the following information:a) sample and test piece details:1) a full description of the sample and its origin,2) compound details and cure details, where appropriate,3) the dimensions of the test piece,4) the num
37、ber of layers in the test piece and the thickness of the thinnest layer,5) in the case of curved or irregularly shaped test pieces, a description of the test piece,6) the method of preparation of the test pieces from the sample, e.g. by moulding or cutting;b) test method:1) a reference to the test m
38、ethod used, i.e. the number of this International Standard,2) for curved test pieces, the way in which the test piece was mounted and the way the test force was applied;c) test details:1) the time and temperature of conditioning prior to the test,2) the temperature of test, and the relative humidity
39、, if necessary,3) details of any procedures not specified in this International Standard;d) test result:1) the number of test pieces tested,2) the individual test results,3) the median result, e.g. 15 VLRH;e) the date of the test.8DIN ISO 27588:2014-12Annex A (normative) Relationship between indenta
40、tion depth and hardness, and derivation of the VLRH scaleAs described in Clause 3, the hardness test measures the difference, D, between the depths of indentation of a ball into the rubber under a small contact force and a large total force. From this difference, the hardness in very low rubber hard
41、ness degrees (VLRH) is obtained. Table A.1 shows the conversion of values of D to very low rubber hardness degrees (VLRH).9DIN ISO 27588:2014-12Table A.1 Conversion of values of D to very low rubber hardness degrees (VLRH)DmVLRHDmVLRHDmVLRH0 100 340 66 680 3210 99 350 65 690 3120 98 360 64 700 3030
42、97 370 63 710 2940 96 380 62 720 2850 95 390 61 730 2760 94 400 60 740 2670 93 410 59 750 2580 92 420 58 760 2490 91 430 57 770 23100 90 440 56 780 22110 89 450 55 790 21120 88 460 54 800 20130 87 470 53 810 19140 86 480 52 820 18150 85 490 51 830 17160 84 500 50 840 16170 83 510 49 850 15180 82 520
43、 48 860 14190 81 530 47 870 13200 80 540 46 880 12210 79 550 45 890 11220 78 560 44 900 10230 77 570 43 910 9240 76 580 42 920 8250 75 590 41 930 7260 74 600 40 940 6270 73 610 39 950 5280 72 620 38 960 4290 71 630 37 970 3300 70 640 36 980 2310 69 650 35 990 1320 68 660 34 1 000 0330 67 670 33 The
44、general mathematical relationship between the depth of penetration, D, and VLRH is given by the equation:VLRH = 100 0,1D (1)Figure A.1 gives a graphical representation of this relationship.10DIN ISO 27588:2014-12Figure A.1 Relationship between the depth of penetration, D, and VLRH11DIN ISO 27588:201
45、4-12Annex B (normative) Calibration scheduleB.1 InspectionBefore any calibration is undertaken, the condition of the items to be calibrated shall be ascertained by inspection and recorded in any calibration report or certificate. It shall be reported whether calibration is made in the “as-received”c
46、ondition or after rectification of any abnormality or fault.It shall be ascertained that the apparatus is generally fit for the intended purpose, including any parameters specified as approximate and for which the apparatus does not therefore need to be formally calibrated. If such parameters are li
47、able to change, then the need for periodic checks shall be written into the detailed calibration procedures.B.2 ScheduleVerification/calibration of the test apparatus is a normative part of this International Standard. However, the frequency of calibration and the procedures used are, unless otherwi
48、se stated, at the discretion of the individual laboratory, using ISO 18898 (for the parameters listed in Table B.1) or ISO 18899 (for the additional items listed below Table B.1) for guidance.The calibration schedule given in Table B.1 has been compiled by listing all of the parameters specified in
49、the test method for the apparatus, together with the specified requirement. A parameter and requirement can relate to the main test apparatus, to part of that apparatus or to an ancillary apparatus necessary for the test.For each parameter, a calibration procedure is indicated by reference to ISO 18898, to another publication or to a procedure particular to the test method which is detailed (whenever a calibration procedure which is more spe
