1、Designation: D750 06D750 12Standard Test Method Practice forRubber Deterioration Using Artificial Weathering Apparatus1This standard is issued under the fixed designation D750; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar 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 specifi
3、c variations in the test conditions and procedures that shall be applicable when Practice G151plus either Practice G152, G153, G154, or G155 are employed for exposure of vulcanized rubber compounds. It also covers thepreparation of test specimens and the evaluation of results.1.2 The values stated i
4、n SI units are to be regarded as standard. The values given in parentheses are for information only.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and heal
5、th practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D412 Test Methods for Vulcanized Rubber and Thermoplastic ElastomersTensionD3182 Practice for RubberMaterials, Equipment, and Procedures for Mixing Standard Compounds and Pre
6、paring StandardVulcanized SheetsD3183 Practice for RubberPreparation of Pieces for Test Purposes from ProductsD4483 Practice for Evaluating Precision for Test Method Standards in the Rubber and Carbon Black Manufacturing IndustriesG151 Practice for Exposing Nonmetallic Materials in Accelerated Test
7、Devices that Use Laboratory Light SourcesG152 Practice for Operating Open Flame Carbon Arc Light Apparatus for Exposure of Nonmetallic MaterialsG153 Practice for Operating Enclosed Carbon Arc Light Apparatus for Exposure of Nonmetallic MaterialsG154 Practice for Operating Fluorescent Ultraviolet (UV
8、) Lamp Apparatus for Exposure of Nonmetallic MaterialsG155 Practice for Operating Xenon Arc Light Apparatus for Exposure of Non-Metallic Materials3. Significance and Use3.1 This test method describes procedures to use in determining the effects of an open-flame carbon-arc light source, an enclosedca
9、rbon-arc light source, a xenon-arc light source, or a fluorescent UV source along with heat and moisture on rubber specimensheld in a jig or holder with or without a specified strain. The purpose is to attempt to accelerate the effects produced by light, heat,and moisture in the natural environment.
10、 Exposures are not intended to simulate the deterioration caused by localized weatherphenomena, such as atmospheric pollution, biological attack, and saltwater exposure. The Significance and Use section in PracticeG151 and the standard for the appropriate apparatus, that is, Practices G152, G153, G1
11、54, or G155 should be consulted foradditional information on significance and use of the exposure tests.3.2 The primary criterion used in estimating resistance to weathering is the percentage decrease in tensile strength and inelongation at break.Asupplementary criterion for estimating resistance to
12、 weathering is the observed extent of surface crazing andcracking.3.3 Results obtained by use of these test procedures should not be represented as equivalent to those of any natural exposuretest until the degree of quantitative correlation has been established for the material in question.1 This te
13、st method is under the jurisdiction of ASTM Committee D11 on Rubber and is the direct responsibility of Subcommittee D11.15 on Degradation Tests.Current edition approved Dec. 1, 2006Dec. 15, 2012. Published December 2006February 2013. Originally approved in 1943. Last previous edition approved in 20
14、002006as D750 00.D750 06. DOI: 10.1520/D0750-06.10.1520/D0750-12.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM webs
15、ite.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior
16、 editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.4 Because of differences in the spectral p
17、ower distributions of the exposure sources as well as the other conditions in thedifferent types of laboratory weathering tests, the different procedures may not result in the same performance rankings or typesof failure modes of the materials. Comparisons shall not be made of relative stabilities o
18、f materials exposed in different types ofapparatus.3.5 When conducting exposures in devices that use laboratory light sources, it is important to consider how well the artificialweathering conditions will reproduce property changes and failure modes caused by end-use environments on the materials be
19、ingtested.3.6 Practices G151, G152, G153, G154, and G155 recommend that a similar material of known performance (a control) beexposed simultaneously with the test specimen to provide a standard for comparative purposes. Preferably, a control materialknown to have poor durability as well as one that
20、has good durability should be used. The reason for using a control is thatreproducibility in ranking stabilities is usually better than reproducibility of absolute changes. Therefore, the use of controls isparticularly important when test materials are not being compared with one another.4. Apparatu
21、s4.1 Historically, this standard utilized carbon arc exposure apparatus in a test method for rubber deterioration. The options ofusing either xenon arc or fluorescent UV exposure apparatus have been added in order to update the tests with the use of lightsources that give a better representation of
22、the effects of solar radiation than carbon arcs. The xenon arc source with daylight filters,which conforms to Practice G155, gives the closest simulation of the full spectrum of terrestrial solar radiation, and the fluorescentUV/condensation test apparatus with the UVA-340 fluorescent UV lamp, which
23、 conforms to Practice G154, closely simulates theUV of terrestrial solar radiation in the 300 to 360 nm region.4.2 The type of carbon-arc exposure apparatus preferred is the filtered open flame carbon arc, which conforms with PracticeG152, but the enclosed carbon arc apparatus conforming with Practi
24、ce G153 may be used by mutual consent of the concernedparties.4.3 Choice of the type of apparatus and duration of exposure shall be by mutual agreement among the interested parties.5. Test Specimens5.1 Unless otherwise mutually agreed upon, test specimens prepared especially for this test or cut fro
25、m the material to beevaluated shall be three tension test replicates prepared in accordance with Practices D3182 and D3183.An additional three tensiontest replicates shall be prepared and stored for testing in accordance with 7.1.3. Unless otherwise mutually agreed upon, thespecimens should have a m
26、aximum thickness of 0.75 mm (0.030 in.) and a minimum thickness 0.60 mm (0.025 in.).5.2 If evaluation is limited only to visual observation, then specimens of any thickness may be used and the thickness shall beincluded in the report. Dimensions of the specimens are not critical but previous practic
27、e called for specimens 75 mm (3 in.) wideby 150 mm (6 in.) in length.5.3 Exposing at least duplicate sets, preferably triplicate sets, of test specimens whenever possible is recommended.5.4 Specimens cut from rubber products may be buffed.6. Procedure6.1 Firmly fasten the test specimens in a jig or
28、holder that permits exposure either with or without elongation. While exposuresare usually made without elongation of the test specimen, when mutually agreed upon, any specified amount of elongation maybe employed but this must be reported in the results of the test.6.2 The four exposure procedures
29、use different types of exposure sources and test conditions. Therefore, they may producedifferent test results. They shall not be used interchangeably without supporting data that demonstrates equivalency of theprocedures for the materials tested.6.3 For the allowed operational fluctuations of the s
30、pecified set points for irradiance, temperature, and relative humidity, referto TableA3.1 in Practice G151. If the actual operating conditions do not comply with the maximum allowable fluctuations in TableA3.1 after the equipment has stabilized, discontinue the test and correct the cause of the prob
31、lem before continuing.6.4 Specimens should be confined to an exposure area in which the irradiance is at least 90 % of the irradiance at the centerof the exposure area. Unless it is known that irradiance uniformity meets this requirement, use one of the procedures describedin Practice G151, Appendix
32、 X2 to ensure equal radiant exposure on all specimens or to compensate for differences within theexposure chamber. If the specimens do not completely fill the racks, fill the empty spaces with blank metal panels to maintain thetest conditions within the chamber.6.5 The apparatus shall be operated co
33、ntinuously. However, if the test needs to be interrupted to perform routine maintenanceor inspection, it should be during a dry period.6.6 Procedure for Exposure in Open Flame Carbon Arc Apparatus (Practice G152) or Enclosed Carbon Arc Apparatus(Practice G153)Unless otherwise specified, use the foll
34、owing operating conditions:D750 1226.6.1 The open flame carbon arc apparatus and the enclosed carbon arc apparatus shall be used with daylight type filters andconform with the spectral power distribution specifications in Practices G152 and G153, respectively.6.6.2 Unless otherwise mutually agreed u
35、pon or specified, operate with a cycle cam of 102 min light followed by 18 min of lightplus water spray on the front surface of the sample (see Note 1). The water spray temperature is typically 21 6 5C, but may belower if ambient water temperature is low and a holding tank is not used to store purif
36、ied water.NOTE 1This cycle is recommended only because it has long historical usage, not because it has been established for technical reasons as superior.6.6.3 Set the uninsulated black panel temperature (BPT) at 63C during the dry period of exposure to light.6.6.4 Set the relative humidity at 60 %
37、 during the dry period of exposure to light.6.7 Procedure for Exposure in Xenon Arc Light Apparatus (Practice G155)Unless otherwise specified, use the followingoperating conditions:6.7.1 The xenon arc shall be used with daylight type filters and conform with the spectral power distribution specifica
38、tions inPractice G155.6.7.2 Set the irradiance level at 0.55 W/(m2nm) at 340 nm. For equivalent broad band irradiance levels at 300 to 400 nm and300 to 800 nm, consult the manufacturer of the apparatus.6.7.3 The default exposure cycle shall be 102 min light only followed by 18 min light plus either
39、water spray on the front surfaceor immersion in water.3 The water spray temperature is typically 21 6 5C, but may be lower if ambient water temperature is lowand a holding tank is not used to store purified water. The immersion water is kept at a constant temperature, which shall be lessthan 40C.NOT
40、E 2Water spray and immersion in water are different kinds of moisture and frequently produce different results.6.7.4 Set the uninsulated black panel temperature (BPT) at 63C during the dry period of exposure to light. For the equivalentinsulated black panel temperature black standard temperature (BS
41、T), consult the manufacturer of the apparatus.6.7.5 Relative humidity shall be set at 60 % during the dry period of exposure to light in xenon arc apparatus that provides forcontrol of relative humidity.6.7.6 The chamber air temperature shall be set at 44C in equipment that provides for adjustment o
42、f the chamber airtemperature.6.8 Procedure for Exposure in Fluorescent UV/Condensation Apparatus (Practice G154)Unless otherwise specified, use thefollowing operating conditions:6.8.1 Use fluorescent UVA-340 lamps that comply with the spectral power distribution specifications in Practice G154.6.8.2
43、 The irradiance level shall be set at 0.77 W/(m2nm) at 340 nm in apparatus with irradiance control.6.8.3 The exposure cycle shall be 8 h UV at an uninsulated black panel temperature of 60C followed by a dark period of 4h with wetting by condensation at an uninsulated black panel temperature of 50C.N
44、OTE 3Wetting by condensation may not be applicable to specimens of insulating materials having a thickness greater than 25 mm because ofinadequate heat transfer.NOTE 4The presence of ozone should be avoided since it can contribute to the crazing and cracking caused by light, heat, and moisture.6.9 T
45、he periods of exposure shall be a mutually agreed upon specified time or amount of radiant energy. It shall be determinedby one of the following procedures (for guidance on minimum exposure, consult Section 8 of Practice G151):6.9.1 A mutually agreed upon specified number of hours,6.9.2 The number o
46、f hours of exposure required to produce mutually agreed upon minimum acceptable changes in either thetest specimen or an agreed upon standard sample, or6.9.3 The number of hours of exposure required to produce a mutually agreed upon minimum amount of change in the exposedtest specimen.7. Interpretat
47、ion of Results7.1 The effects of exposure shall be determined in the following manner:7.1.1 At the conclusion of the exposure interval the specimens shall be removed from the exposure test apparatus and examinedvisually for indications of crazing and cracking.The number and degree of cracks and craz
48、es shall be reported by a mutually agreedupon method.7.1.2 The tensile strength and ultimate elongation of these replicates shall be determined in accordance with Test MethodsD412.7.1.3 For the purpose of comparison, tensile strength and elongation of duplicate unexposed specimens of the same materi
49、alshall be determined at the time the exposed replicates are tested.3 In the immersion technique, the test specimens are placed in a chamber that is periodically flooded with either recirculated or running water, which completely coversthe specimens. The maximum temperature attained by a black colored specimen is determined with the black standard thermometer (BST) held under water on the same planeand distance from the surface as the test specimens. The immersion system is made from corrosion resistant materials that do not contaminate the water.D750 123
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