1、Designation: D 750 06Standard Test Method forRubber Deterioration Using Artificial Weathering Apparatus1This standard is issued under the fixed designation D 750; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last rev
2、ision. 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 covers specific variations
3、in the testconditions and procedures that shall be applicable whenPractice G 151 plus either Practice G 152, G 153, G 154,orG 155 are employed for exposure of vulcanized rubber com-pounds. It also covers the preparation of test specimens and theevaluation of results.1.2 The values stated in SI units
4、 are to be 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 pract
5、ices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 412 Test Methods for Vulcanized Rubber and Thermo-plastic ElastomersTensionD 3182 Practice for RubberMaterials, Equipment, andProcedures for Mixing Standard Compounds and Prepar-
6、ing Standard Vulcanized SheetsD 3183 Practice for RubberPreparation of Pieces for TestPurposes from ProductsD 4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustriesG 151 Practice for Exposing Nonmetallic Materials in Ac-celerated Test D
7、evices that Use Laboratory Light SourcesG 152 Practice for Operating Open Flame CarbonArc LightApparatus for Exposure of Nonmetallic MaterialsG 153 Practice for Operating Enclosed Carbon Arc LightApparatus for Exposure of Nonmetallic MaterialsG 154 Practice for Operating Fluorescent Light Apparatusf
8、or UV Exposure of Nonmetallic MaterialsG 155 Practice for Operating Xenon Arc Light Apparatusfor Exposure of Non-Metallic Materials3. Significance and Use3.1 This test method describes procedures to use in deter-mining the effects of an open-flame carbon-arc light source, anenclosed carbon-arc light
9、 source, a xenon-arc light source, or afluorescent UV source along with heat and moisture on rubberspecimens held in a jig or holder with or without a specifiedstrain. The purpose is to attempt to accelerate the effectsproduced by light, heat, and moisture in the natural environ-ment. Exposures are
10、not intended to simulate the deteriorationcaused by localized weather phenomena, such as atmosphericpollution, biological attack, and saltwater exposure. The Sig-nificance and Use section in Practice G 151 and the standardfor the appropriate apparatus, that is, Practices G 152, G 153,G 154,orG 155 s
11、hould be consulted for additional informationon significance and use of the exposure tests.3.2 The primary criterion used in estimating resistance toweathering is the percentage decrease in tensile strength and inelongation at break. A supplementary criterion for estimatingresistance to weathering i
12、s the observed extent of surfacecrazing and cracking.3.3 Results obtained by use of these test procedures shouldnot be represented as equivalent to those of any naturalexposure test until the degree of quantitative correlation hasbeen established for the material in question.3.4 Because of differenc
13、es in the spectral power distribu-tions of the exposure sources as well as the other conditions inthe different types of laboratory weathering tests, the differentprocedures may not result in the same performance rankings ortypes of failure modes of the materials. Comparisons shall notbe made of rel
14、ative stabilities of materials exposed in differenttypes of apparatus.3.5 When conducting exposures in devices that use labora-tory light sources, it is important to consider how well theartificial weathering conditions will reproduce property1This test method is under the jurisdiction of ASTM Commi
15、ttee D11 on Rubberand is the direct responsibility of Subcommittee D11.15 on Degradation Tests.Current edition approved Dec. 1, 2006. Published December 2006. Originallyapproved in 1943. Last previous edition approved in 2000 as D 750 00.2For referenced ASTM standards, visit the ASTM website, www.as
16、tm.org, orcontact ASTM Customer 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.changes
17、and failure modes caused by end-use environments onthe materials being tested.3.6 Practices G 151, G 152, G 153, G 154, and G 155 rec-ommend that a similar material of known performance (acontrol) be exposed simultaneously with the test specimen toprovide a standard for comparative purposes. Prefera
18、bly, acontrol material known to have poor durability as well as onethat has good durability should be used. The reason for usinga control is that reproducibility in ranking stabilities is usuallybetter than reproducibility of absolute changes. Therefore, theuse of controls is particularly important
19、when test materials arenot being compared with one another.4. Apparatus4.1 Historically, this standard utilized carbon arc exposureapparatus in a test method for rubber deterioration. The optionsof using either xenon arc or fluorescent UV exposure apparatushave been added in order to update the test
20、s with the use oflight sources that give a better representation of the effects ofsolar radiation than carbon arcs. The xenon arc source withdaylight filters, which conforms to Practice G 155, gives theclosest simulation of the full spectrum of terrestrial solarradiation, and the fluorescent UV/cond
21、ensation test apparatuswith the UVA-340 fluorescent UV lamp, which conforms toPractice G 154, closely simulates the UV of terrestrial solarradiation in the 300 to 360 nm region.4.2 The type of carbon-arc exposure apparatus preferred isthe filtered open flame carbon arc, which conforms withPractice G
22、 152, but the enclosed carbon arc apparatus conform-ing with Practice G 153 may be used by mutual consent of theconcerned parties.4.3 Choice of the type of apparatus and duration of exposureshall be by mutual agreement among the interested parties.5. Test Specimens5.1 Unless otherwise mutually agree
23、d upon, test specimensprepared especially for this test or cut from the material to beevaluated shall be three tension test replicates prepared inaccordance with Practices D 3182 and D 3183. An additionalthree tension test replicates shall be prepared and stored fortesting in accordance with 7.1.3.
24、Unless otherwise mutuallyagreed upon, the specimens should have a maximum thicknessof 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, thenspecimens of any thickness may be used and the thickness shallbe included in the report. D
25、imensions of the specimens are notcritical but previous practice called for specimens 75 mm(3 in.) wide by 150 mm (6 in.) in length.5.3 Exposing at least duplicate sets, preferably triplicatesets, of test specimens whenever possible is recommended.5.4 Specimens cut from rubber products may be buffed
26、.6. Procedure6.1 Firmly fasten the test specimens in a jig or holder thatpermits exposure either with or without elongation. Whileexposures are usually made without elongation of the testspecimen, when mutually agreed upon, any specified amountof elongation may be employed but this must be reported
27、in theresults of the test.6.2 The four exposure procedures use different types ofexposure sources and test conditions. Therefore, they mayproduce different test results. They shall not be used inter-changeably without supporting data that demonstrates equiva-lency of the procedures for the materials
28、 tested.6.3 For the allowed operational fluctuations of the specifiedset points for irradiance, temperature, and relative humidity,refer to Table A3.1 in Practice G 151. If the actual operatingconditions do not comply with the maximum allowable fluc-tuations in Table A3.1 after the equipment has sta
29、bilized,discontinue the test and correct the cause of the problem beforecontinuing.6.4 Specimens should be confined to an exposure area inwhich the irradiance is at least 90 % of the irradiance at thecenter of the exposure area. Unless it is known that irradianceuniformity meets this requirement, us
30、e one of the proceduresdescribed in Practice G 151, Appendix X2 to ensure equalradiant exposure on all specimens or to compensate fordifferences within the exposure chamber. If the specimens donot completely fill the racks, fill the empty spaces with blankmetal panels to maintain the test conditions
31、 within the cham-ber.6.5 The apparatus shall be operated continuously. However,if the test needs to be interrupted to perform routine mainte-nance or inspection, it should be during a dry period.6.6 Procedure for Exposure in Open Flame Carbon ArcApparatus (Practice G 152) or Enclosed Carbon Arc Appa
32、ra-tus (Practice G 153)Unless otherwise specified, use thefollowing operating conditions:6.6.1 The open flame carbon arc apparatus and the enclosedcarbon arc apparatus shall be used with daylight type filters andconform with the spectral power distribution specifications inPractices G 152 and G 153,
33、 respectively.6.6.2 Unless otherwise mutually agreed upon or specified,operate with a cycle cam of 102 min light followed by 18 minof light plus water spray on the front surface of the sample (seeNote 1). The water spray temperature is typically 21 6 5C,but may be lower if ambient water temperature
34、is low and aholding tank is not used to store purified water.NOTE 1This cycle is recommended only because it has long historicalusage, not because it has been established for technical reasons assuperior.6.6.3 Set the uninsulated black panel temperature (BPT) at63C during the dry period of exposure
35、to light.6.6.4 Set the relative humidity at 60 % during the dry periodof exposure to light.6.7 Procedure for Exposure in Xenon Arc Light Apparatus(Practice G 155)Unless otherwise specified, use the follow-ing operating conditions:6.7.1 The xenon arc shall be used with daylight type filtersand confor
36、m with the spectral power distribution specificationsin Practice G 155.6.7.2 Set the irradiance level at 0.55 W/(m2nm) at 340 nm.For equivalent broad band irradiance levels at 300 to 400 nmand 300 to 800 nm, consult the manufacturer of the apparatus.D7500626.7.3 The default exposure cycle shall be 1
37、02 min light onlyfollowed by 18 min light plus either water spray on the frontsurface or immersion in water.3The water spray temperature istypically 21 6 5C, but may be lower if ambient watertemperature is low and a holding tank is not used to storepurified water. The immersion water is kept at a co
38、nstanttemperature, which shall be less than 40C.NOTE 2Water spray and immersion in water are different kinds ofmoisture and frequently produce different results.6.7.4 Set the uninsulated black panel temperature (BPT) at63C during the dry period of exposure to light. For theequivalent insulated black
39、 panel temperature black standardtemperature (BST), consult the manufacturer of the apparatus.6.7.5 Relative humidity shall be set at 60 % during the dryperiod of exposure to light in xenon arc apparatus that providesfor control of relative humidity.6.7.6 The chamber air temperature shall be set at
40、44C inequipment that provides for adjustment of the chamber airtemperature.6.8 Procedure for Exposure in Fluorescent UV/Condensation Apparatus (Practice G 154)Unless otherwisespecified, use the following operating conditions:6.8.1 Use fluorescent UVA-340 lamps that comply with thespectral power dist
41、ribution specifications in Practice G 154.6.8.2 The irradiance level shall be set at 0.77 W/(m2nm) at340 nm in apparatus with irradiance control.6.8.3 The exposure cycle shall be8hUVatanuninsulatedblack panel temperature of 60C followed by a dark period of4 h with wetting by condensation at an unins
42、ulated black paneltemperature of 50C.NOTE 3Wetting by condensation may not be applicable to specimensof insulating materials having a thickness greater than 25 mm because ofinadequate heat transfer.NOTE 4The presence of ozone should be avoided since it cancontribute to the crazing and cracking cause
43、d by light, heat, and moisture.6.9 The periods of exposure shall be a mutually agreed uponspecified time or amount of radiant energy. It shall be deter-mined by one of the following procedures (for guidance onminimum exposure, consult Section 8 of Practice G 151):6.9.1 A mutually agreed upon specifi
44、ed number of hours,6.9.2 The number of hours of exposure required to producemutually agreed upon minimum acceptable changes in eitherthe test specimen or an agreed upon standard sample, or6.9.3 The number of hours of exposure required to producea mutually agreed upon minimum amount of change in thee
45、xposed test specimen.7. Interpretation of Results7.1 The effects of exposure shall be determined in thefollowing manner:7.1.1 At the conclusion of the exposure interval the speci-mens shall be removed from the exposure test apparatus andexamined visually for indications of crazing and cracking. Then
46、umber and degree of cracks and crazes shall be reported by amutually agreed upon method.7.1.2 The tensile strength and ultimate elongation of thesereplicates shall be determined in accordance with Test MethodsD 412.7.1.3 For the purpose of comparison, tensile strength andelongation of duplicate unex
47、posed specimens of the samematerial shall be determined at the time the exposed replicatesare tested.8. Report8.1 In addition to the report requirements of Practice G 151,report the following additional information:8.1.1 Any variations from the specified conditions,8.1.2 Description and dimensions o
48、f specimens,8.1.3 Number of cracks and degree of crazing or cracking ofthe specimens,8.1.4 Percentage of elongation during exposure, if any,8.1.5 Tensile strength in kilopascals (or pounds-force persquare inch) before and after exposure,8.1.6 Ultimate elongation at break before and after expo-sure,8
49、.1.7 Percentage loss in tensile strength as a result ofexposure,8.1.8 Percentage loss in elongation at break as a result ofexposure, and8.1.9 Chlorine content of the water.9. Precision and Bias9.1 Precision and bias statements will be prepared in theform specified by Practice D 4483. They will be added to thistest method when they are completed.10. Keywords10.1 enclosed carbon arc; filtered open flame carbon arc;filtered xenon arc; rubber products; ultraviolet and ultraviolet/visible light aging; weathering3In the immersion technique, the test specimens are place
