1、Designation: D 1171 99Standard Test Method forRubber DeteriorationSurface Ozone Cracking Outdoors orChamber (Triangular Specimens)1This standard is issued under the fixed designation D 1171; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method
3、 permits the estimation of the relativeability of rubber compounds used for applications requiringresistance to outdoor weathering or ozone chamber testing.1.2 This test method is not applicable to materials ordinarilyclassed as hard rubber, but is adaptable to molded or extrudedsoft rubber material
4、s and sponge rubber for use in windowweatherstripping as well as similar automotive applications.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health
5、practices and determine the applica-bility of regulatory limitations prior to use. For a specifichazard statement, see Note 1 and 8.1.NOTE 1WarningOzone is a hazardous chemical.2. Referenced Documents2.1 ASTM Standards:D 518 Test Method for Rubber DeteriorationSurfaceCracking2D 1149 Test Method for
6、Rubber DeteriorationSurfaceOzone Cracking in a Chamber2D 4575 Test Method for Rubber Deterioration: ReferenceandAlternative Method(s) for Determining Ozone Level inLaboratory Test Chambers23. Summary of Test Method3.1 Procedures are given for preparing triangular cross-section specimens, for mountin
7、g them in strained conditionaround specified circular mandrels, and for rating the effect ofexposure as evidenced by the appearance of surface cracks.The type, time, temperature, and other conditions of exposureare not given but shall be agreed upon by the purchaser and theseller and shall be comple
8、tely described in the test reports.3.2 Two techniques are described, the exposure rating andthe quality-retention rating.3.3 Refer to D 4575 for the reference and optional alterna-tive methods for the measurement of the ozone partial pressurein laboratory test chambers.4. Significance and Use4.1 Mol
9、ded or extruded rubber products must withstand theeffects of ozone cracking and outdoor weathering for satisfac-tory use. This test enables a simple comparison of performanceto be made under specified test conditions, either in a labora-tory test chamber or in an outdoor test. No direct correlationb
10、etween test performance and service performance can beclaimed due to the wide range of service conditions.5. Apparatus5.1 Mounting Mandrel A wood mandrel 50 mm (2 in.) inoutside diameter, suitably coated with spar varnish or a clearlacquer. The mandrel may be supported by any convenientmethod.5.2 Fa
11、stening Wire Enameled copper wire.5.3 Test Chamber An ozone chamber as described in TestMethod D 1149.6. Test Specimen6.1 The triangular cross-section test specimen shall be amolded, extruded, or sponge section with a continuous skin orsurface layer, 250 mm (10 in.) long, and cured in a straightposi
12、tion. The cross-sectional dimensions shall be as shown inFig. 1. Duplicate specimens shall be tested.6.2 It is recommended that the manufacturer observe aminimum rest period of 24 h between compound mixing andcompound preparation, and a minimum rest period of12 hbetween compound preparation and curi
13、ng when preparingspecimens. The finish of the specimens shall be as smooth aspossible.1This test method is under the jurisdiction of ASTM Committee D-11 on Rubberand is the direct responsibility of Subcommittee D11.15 on Degradation Tests.Current edition approved Nov. 10, 1999. Published December 19
14、99. Originallypublished as D 1171 51 T. Last previous edition D 117194.2Annual Book of ASTM Standards, Vol 09.01.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.METHOD AEXPOSURE RATING7. Procedure7.1 Mounting of SpecimensPlace bench
15、marks on eachspecimen with a crayon, 190 mm (7.5 in.) apart and 32 mm(1.25 in.) from the ends. Form the specimens into a loop byplacing the 19-mm (0.75-in.) sides together and tying securelywith wire at the bench marks. Slip the complete loop over themandrel. Place as many specimens on the mandrels
16、as length ofmandrel will permit.7.2 Exposure of Specimens:7.2.1 Conditioning Period:7.2.1.1 Outdoor Exposure After the specimens aremounted allow them to condition for 70 to 72 h at roomtemperature in an ozone free atmosphere. Do not touch thelooped part after mounting until the test is completed.7.
17、2.1.2 Ozone Chamber ExposureAfter the specimens aremounted allow them to condition for 70 to 72 h at 40 6 C(104 6 2F) either in a temperature controlled cabinet orpreferably in the ozone cabinet itself. After this conditioningperiod transfer to the ozone chamber or, if already conditioningin this ap
18、paratus, switch on the ozone so that it rises to a levelof 50 6 5 mPa partial ozone pressure.7.2.2 Angle and Direction and Positioning of Exposures:7.2.2.1 Incline specimens exposed outdoors so that theportion of the loop diametrically opposite the tied ends shallface south at an angle of 45 with th
19、e horizontal as shown inFig. 2.7.2.2.2 Ozone Chamber ExposurePosition in the chamberin which ozone is controlled as described in Test MethodD 4575. The position of mounted specimens exposed in theozone test chamber shall be such that there is completecirculation of air around the specimens and the s
20、pecimens donot touch anything during the necessary handling.7.2.3 Test Conditions:7.2.3.1 Outdoor Exposure The type, time, temperature,and other essential conditions of exposure shall be agreed uponby the purchaser and the seller.7.2.3.2 Ozone-Chamber Exposure Method AExposespecimens for 72 h at 40
21、6 1C (104 6 2F) at an ozone levelof 50 6 5 mPa partial ozone pressure, unless otherwisespecified by agreement between the purchaser and the seller.The specimens may be removed from the test chamber after 24,48 and 72-h exposure for rating.7.2.3.3 Ozone-Chamber Exposure Method BOn materialsknown to b
22、e substantially resistant to ozone, test specimensand fixtures as described under Procedure B in Test MethodD 518 may be used. Expose specimens for 70 h at 406 1C(104 6 2F) at an ozone level of 50 6 5 mPa partial ozonepressure, unless otherwise specified by agreement between thepurchaser and seller.
23、 The specimens may be removed from thetest chamber after 22, 46, and 70-h exposure, for examination.7.3 Rating of Exposed SpecimensWhen the specifiedexposure period is completed, examine the specimens beforeremoval from the mandrel, and evaluate the degree of crackingby comparison with the reference
24、 standards shown in Fig. 3using a 2-power headgear binocular magnifier or equivalent. Ifthe size of the cracks at 23 magnification is less than thoseshown on one photograph but greater than those shown on thenext lower rating picture, give the lower rating.7.4 In ozone chamber exposure Method B, no
25、rating isintended, rather, there shall be no cracks permitted under 23magnification.8. Hazards8.1 WarningOzone is a hazardous substance. Consultand follow all applicable laws, rules, and regulations re-garding exposure to ozone.9. Report9.1 Report the following information:9.1.1 Description of the s
26、pecimen, giving the identificationnumber of compound and vulcanization data, if known, includ-ing date,9.1.2 Date of start of exposure, and complete informationdescribing conditions of exposure,9.1.3 Rating number of exposed specimens, and9.1.4 If desired, a photograph at 23 magnification.METHOD BQU
27、ALITY-RETENTION RATING10. Procedure10.1 If it is desired to apply a quality-retention rating valuebased on three observations of crack rating taken at threesuccessive time intervals of exposure, use the followingprocedure:FIG. 1 Cross-Sectional Dimension of Test SpecimensFIG. 2 Outdoor Exposure of T
28、est SpecimenD117199210.1.1 Prepare the test specimens as described in Section 6,and mount and expose as described in 7.1 and 7.2 except thatthe time of exposure shall be six weeks. Other periods ofoutdoor exposure may be used if agreed upon by producer andconsumer. Make the crack rating as described
29、 in 7.3 everysecond week or at three equal intervals. This will give threeratings.10.1.2 The three crack-growth ratings shall be put togetherto give a three-digit number and Table 1 then used to find thepercent quality retention. The three-digit crack-growth numberin the crack-growth column correspo
30、nds to the quality reten-tion in the right-hand column.11. Report11.1 Report the following information:11.1.1 Description of the specimen, giving the identificationnumber of the compound and date of vulcanization,11.1.2 Date of start of exposure and complete informationdescribing condition of exposu
31、re,11.1.3 Crack rating number composed of three digits repre-senting three readings taken each two weeks for six weeks ortaken at three equal intervals, and11.1.4 Quality-retention value in percent.12. Precision and Bias12.1 Both the exposure rating and the quality-retentionrating are essentially ra
32、nk order or qualitative comparisonmethods. Precision as normally expressed for quantitative-measurement test methods is not directly applicable.13. Keywords13.1 crack growth; cracking; ozone; ozone cracking; surfacecrack; triangular; weatheringRating 0 Rating 1 Rating 2 Rating 3FIG. 3 Ratings for We
33、athering Tests of Rubber Compounds (Specimens mounted on mandrel.) (23)TABLE 1 Quality Retention RatingCrack Growth Quality Retention, %000 100001 95011 90111 85002 80012 75112 70022 65122 60222 55003 45013 40113 35023 30123 25223 20033 15133 10233 5333 0D1171993ASTM International takes no position
34、respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.Th
35、is standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM Int
36、ernational Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown
37、 below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D1171994
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