1、Designation: D 1229 03 (Reapproved 2008)Standard Test Method forRubber PropertyCompression Set at Low Temperatures1This standard is issued under the fixed designation D 1229; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、 of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () 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 covers evaluatio
3、n of the ability ofvulcanized rubbers that have been compressed at room tem-perature and then subjected to low temperature (air or carbondioxide atmosphere), to recover from deformation when takenfrom the clamping device while still at the low temperature.1.2 The values stated in SI units are to be
4、regarded as thestandard. The values given in parentheses are for informationonly.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 practices and de
5、termine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 395 Test Methods for Rubber PropertyCompressionSetD 832 Practice for Rubber Conditioning For Low Tempera-ture TestingD 3767 Practice for RubberMeasurement of DimensionsD 4483 Practice for E
6、valuating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustries3. Summary of Test Method3.1 At room temperature, a test specimen is compressed to25 % of its original thickness and exposed for a specified timeat a specified low temperature.3.2 Upon release from com
7、pression, the specimen is al-lowed to recover while remaining at the test temperature.3.3 The residual deformation of the specimen is measured10 s and 30 min after removal from the compressive device.3.4 Compression set of the specimen is calculated accordingto the equations in 9.1.4. Significance a
8、nd Use4.1 Rubber products, such as hydraulic seals on aircraft,submarine hatch gaskets, and hydraulic brake cups, may beexposed to varying temperature extremes. This test methodprovides a means of determining the extent to which recoveryfrom compression at normal ambient temperatures is inhibitedupo
9、n release of the compressive force during subsequentexposure at low temperatures.5. Compression Set5.1 For the purpose of this test method, compression set ofvulcanizates shall be the loss in thickness of the specimenexpressed as a percentage of the original deflection. This set,unlike conventional
10、compression set at elevated temperatures,is temporary since the specimen will regain its originaldimensions when brought back to room temperature or slightlyabove.6. Apparatus6.1 Compression Set Jigs, with suitable steel spacer bars inaccordance with Method B of Test Methods D 395.6.2 Dial Micromete
11、r, as described in Practice D 3767.6.3 Cold Box, cooled by solid carbon dioxide (Dry Ice),liquid carbon dioxide, liquid nitrogen, or mechanically refrig-erated, preferably by the top-opening type, and capable oftemperature control within 61C (1.8F) of the specifiedtesting temperature as prescribed i
12、n Practice D 832. The testchamber shall be equipped with a vise, “C” clamp, or othersuitable device for holding the compression set jig.7. Test Specimen7.1 The standard test specimen shall be a cylindrical disk29.0 6 0.5 mm (1.14 6 0.02 in.) in diameter and 12.5 6 0.5mm (0.49 6 0.02 in.) in thicknes
13、s, as specified in Test MethodsD 395.8. Procedure8.1 Original Thickness MeasurementMeasure the originalthickness, to, at the center of the specimen to the nearest 0.02mm (0.001 in.).1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand is the direct responsibility of Subcomm
14、ittee D11.14 on Time and Temperature-Dependent Physical Properties.Current edition approved May 1, 2008. Published June 2008. Originallyapproved in 1952. Last previous edition approved in 2003 as D 1229 03.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer
15、Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.8.2 Application of LoadPlace a test spec
16、imen betweenclean, unlubricated plates of the compression device with thespacers on each side of it. Use only one specimen with eachpair of steel plates, and place in the center between the plates.Tighten the bolts so as to draw the plates together uniformlyuntil they are in contact with the spacers
17、. The compressionemployed shall be 25 % for all hardnesses.8.3 Within 30 min after the jigs are loaded, place them in thelow-temperature cabinet, and maintain at the service tempera-ture for which the vulcanizates are being evaluated. In theevent the service temperature is unknown, the followingtemp
18、eratures are suggested: 40C (40F) and 55C(67F). The conditioning period shall be either 22 or 94 h. Atleast 1 h before the conditioning period is over, place the dialmicrometer in the test chamber and clamp one of the set jigs inthe vise or “C” clamp provided in the low-temperature cham-ber. Use sui
19、table gloves for all operations in the test chamber.At the end of the conditioning period, remove the nuts from thejig, after which release the vise or “C” clamp, and start the stopwatch simultaneously. Measure the thickness of the specimens10 s and again 30 min after release from the vise or “C” cl
20、ampand record as t10and t30, respectively. Since the test isconducted at a specific temperature, within 61C (1.8F), theschedule of opening the jigs shall be such that the test chamberwill stay within the permissible variations in temperature.NOTE 1It is convenient when conducting many tests to have
21、the dialmicrometer outside the chamber and have an extended insulated stem passthrough the cover or the top to measure the thickness of specimens afterrelease from compression.NOTE 2Slowly crystallizing rubbers may need to be tested at 10C(14F) or 25C (13F), with a conditioning period of 166 h.NOTE
22、3In the event that the dail micrometer gage being used isunacceptable for use at a low temperature, it may be placed outside of thetest chamber. The test specimen is to remain in the cold box until it ismeasured. Immediately upon removal from the chamber the first measure-ment, t10, is to be taken a
23、nd the specimen immediately returned to the coldbox. At the 30 min time interval the specimen is again removed from thechamber and immediately measured to obtain the value for t30.8.4 Check TestRun tests in duplicate. The results shouldagree within 5.0 %.9. Calculation9.1 Calculate the compression s
24、et, expressed as a percentageof the original deflection, as follows:C 5 t02 t10!/t02 ts! 3 100 (1)orC 5 t02 t30!/t02 ts! 3 100 (2)where:C = compression set expressed as a percentage of theoriginal deflection, andts= thickness of the spacer bar used.10. Report10.1 The report shall include the followi
25、ng:10.1.1 The original thickness of the test specimen,10.1.2 The percentage compression of the specimen actu-ally employed,10.1.3 The thickness of the test specimen 10 s, t10, and 30min, t30, after removal from the clamp, and10.1.4 The compression set expressed as a percentage of theoriginal deflect
26、ion.11. Precision and Bias311.1 This precision and bias section was prepared in accor-dance with Practice D 4483. Refer to Practice D 4483 forterminology and other statistical calculation details.11.2 Although prepared in accordance with PracticeD 4483, the data generated for this test method were o
27、btainedprior to the adoption of Practice D 4483 in 1985. No recordsexist for the original test program. The values of within-and-between laboratory standard deviation have been used toconstruct Table 1. A Type 1 precision was evaluated.11.3 Compression set test specimens were prepared in onelaborato
28、ry from three different rubber compounds. Ten labora-tories tested two specimens from each of these compounds on4 different days. The precision statements are based on theaverage of two measurements and are expressed in terms of thecompression set, in percent.11.4 The precision of this test method m
29、ay be expressed inthe format of the following statements which use what is calledan “appropriate value” or r, R, (r), or (R), that is, that value tobe used in decisions about test results (obtained with the test3Supporting data have been filed at ASTM International Headquarters and maybe obtained by
30、 requesting Research Report RR: D11-1042.TABLE 1 Type 1 Precision, Compression Set, %NOTESr= Within laboratory standard deviation.r = Repeatability (in measurement units).(r) = Repeatability (in percent).SR= Between laboratory standard deviation.R = Reproducibility (in measurement units).(R) = Repro
31、ducibility (in percent).Materials Measured AtRange ofValues, %Within Laboratories Between LaboratoriesSrr (r) SRR(R)Three unknown compounds 10 s 75 to 104 0.60 1.70 1.9A2.60 7.4 8.2AThree unknown compounds 30 min 42 to 93 1.60 4.5 6.6A5.60 15.8 23.2AAAn estimated value of relative repeatability (r)
32、and reproducibility (R) using the mid-point of the range.D 1229 03 (2008)2method). The appropriate value is that value of r or Rassociated with a mean level in Table 1 closest to the meanlevel under consideration at any given time, for any givenmaterial in routine testing operations.11.5 Repeatabili
33、tyThe repeatability, r, of this test methodhas been established as the appropriate value tabulated in Table1. Two single test results, obtained under normal test methodprocedures, that differ by more than this tabulated r (for anygiven level) must be considered as derived from different ornonidentic
34、al sample populations.11.6 ReproducibilityThe reproducibility, R, of this testmethod has been established as the appropriate value tabulatedin Table 1. Two single test results obtained in two differentlaboratories, under normal test method procedures, that differby more than the tabulated R (for any
35、 given level) must beconsidered to have come from different or nonidentical samplepopulations.11.7 Repeatability and reproducibility expressed as a per-centage of the mean level, (r) and (R), have equivalentapplication statements as above for r and R. For the (r) and (R)statements, the difference in
36、 the two single test results isexpressed as a percentage of the arithmetic mean of the two testresults.11.8 BiasIn test method terminology, bias is the differ-ence between an average test value and the reference (or true)test property value. Reference values do not exist for this testmethod since th
37、e value (of the test property) is exclusivelydefined by the test method. Bias, therefore, cannot be deter-mined.12. Keywords12.1 compression set; low temperatureASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this sta
38、ndard. 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.This standard is subject to revision at any time by the responsible technical committee and must be revi
39、ewed 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 International Headquarters. Your comments will receive careful consideration at a meeting of theresponsib
40、le 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 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).D 1229 03 (2008)3
