1、Designation: D 6789 02e2An American National StandardStandard Test Method forAccelerated Light Aging of Printing and Writing Paper byXenon-Arc Exposure Apparatus1This standard is issued under the fixed designation D 6789; the number immediately following the designation indicates the year oforiginal
2、 adoption or, in the case of revision, 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.e1NOTEReference to a research report was added in September 2003.e2NOTEResearc
3、h Report D061004 was editorially replaced with Adjunct ADJD06PAPERAGING in March 2007.1. Scope1.1 This test method describes a laboratory procedure forthe exposure of printing and writing paper to xenon-arc light atelevated levels of light flux to permit accelerated aging of thattype of paper.1.2 Th
4、is test method specifies the sample preparation andconditions of exposure required to obtain information on therelative stability of paper with regard to change in opticalproperties brought about by exposure of such paper to light.1.3 This test method provides qualitative results regardingpaper stab
5、ility and does not define the life expectancy for agiven paper to reach a specified set of optical properties.1.4 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 safet
6、y and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 685 Practice for Conditioning Paper and Paper Productsfor TestingD 985 Test Method for Brightness of Pulp, Paper, andPaperboard (Directional Reflectance at 457
7、nm)D 1968 Terminology Relating to Paper and Paper ProductsG113 Terminology Relating to Natural and ArtificialWeathering Tests of Nonmetallic MaterialsG 151 Practice for Exposing Nonmetallic Materials in Ac-celerated Test Devices that Use Laboratory Light SourcesG 155 Practice for Operating Xenon Arc
8、 Light Apparatusfor Exposure of Non-Metallic Materials2.2 ASTM Adjuncts:ASTM Paper Aging Research Program32.3 TAPPI Test Methods:T 254 Cupriethylenediamine Disperse Viscosity of Pulp(Falling Ball Method)4T 524 Color of Paper and Paperboard (45/0 Geometry)4T 1206 Precision Statement for Test Methods4
9、3. Terminology3.1 DefinitionsDefinitions shall be in accordance withTerminology D 1968 or Terminology G113. For terms used inthis specification which are not provided by TerminologyD 1968 or Terminology G113, see the Dictionary of Paper.54. Summary of Test Method4.1 In this test method, light from a
10、 xenon-arc lamp thatmakes use of filters to simulate natural daylight that has passedthrough window glass is shone on a paper surface with lightflux that is substantially greater than in normal indoor condi-tions of paper exposure. The light flux is applied in a controlledmanner and for a specified
11、period of time. The light flux causesphotochemical reactions in the paper that change its reflectance(brightness) and color. By comparing initial and final levels ofthese parameters against difference criteria, a measure ofoptical stability is obtained.5. Significance and Use5.1 This test method wil
12、l find use by parties concernedabout the relative optical stability of various printing andwriting papers.5.2 The test will provide manufacturers, paper users andother interested parties with quantified rankings of paper1This test method is under the jurisdiction of ASTM Committee D06 on Paperand Pa
13、per Products and is the direct responsibility of Subcommittee D06.92 onStandard Documents Relating to Paper and Paper Products.Current edition approved Oct. 10, 2002. Published December 2002.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serv
14、iceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from ASTM International Headquarters. Order AdjunctNo.ADJD06PAPERAGING. Formerly Research Report D061004.4Available from Technical Association of the Pulp and
15、Paper Industry (TAPPI),P.O. Box 105113,Atlanta, GA30348; 15 Technology Parkway South, Norcross, GA30092.5Available from TAPPI, 5th ed., 1996.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.stability that identify papers that are stab
16、le, moderately stableand unstable when exposed to light over periods of time.5.3 The stability rankings may be used for definition of therelative stability of papers to light exposure, but will not definespecific periods of life expectancy of a given paper.6. Apparatus6.1 Provide a test chamber that
17、 utilizes a sealed “long-arc”xenon lamp to illuminate the test samples. The lamp spectrumshall be in accordance with Practice G 155, as per Table 2 ofthat document.6.2 Use a glass filtration system in front of the lamp tosimulate natural daylight that has passed through windowglass. This is to cut o
18、ff almost all of the very short wavelengthlight (nominally that which is below 320 nm) as occurs whendaylight passes through window glass. Provide the glassfiltration system as defined in Practice G 155.6.3 Provide a cooling system with the instrument such thattemperature at the paper surface is mai
19、ntained at $20C and#30C for all paper types. Air may be used as a coolingmedium, but is not mandated so long as relative humidity ofabout 0.007 kg water/kg of dry air is maintained in theatmosphere above the paper surface and that a supply ofoxygen, approximately equivalent to that which is found in
20、standard air, is present at the paper surface. Apart from theoxygen, the remainder of the gas present shall be inert.6.4 Utilize a test chamber that is designed such that it can beoperated so as to ensure that it is free of ozone gas.7. Calibration7.1 Control the intensity irradiance (E) of the xeno
21、n arclamp to 765 6 75 W/m2as measured in the 290 to 800 nmwavelength range.7.2 Recalibrate the instrument with sufficient frequency toensure continual preservation of both the light spectrum andthe light intensity. For recalibration frequency recommenda-tions, refer to the manufacturers instructions
22、 for the particularinstrument in use.7.3 Arrange the configuration of the test chamber so as toensure uniformity of light intensity (irradiance) across thepaper sample area and in a way that provides#10 % deviationfrom target intensity.7.4 Check the temperature at the paper surface with suffi-cient
23、frequency to ensure that it is at $20C and #30Cthroughout the test. Make these measurements with a properlycalibrated optical pyrometer.8. Conditioning8.1 Condition all test specimens in the dark prior to and atcompletion of the light aging exposure in accordance withPractice D 685.9. Procedure9.1 A
24、t all times throughout this test procedure, handle papersamples only with clean cotton gloves. This means that cleancotton gloves are required for handling of the paper both beforeand following the aging procedure.9.2 Divide the sample equally into two parts. Use one partfor exposure in the chamber.
25、 Cut a test specimen from this partto the size specified for testing by the test chamber manufac-turer. Use the other for optical property tests of the unexposedpaper. This is necessary to allow for proper light exposure inthe chamber and at the same time to provide enough paper ineach part to be cu
26、t to the small specimen size required forperformance of subsequent standard optical property tests.9.3 Measure the initial optical properties on both sides ofthe unexposed paper specimens after conditioning and justprior to insertion in the test chamber. The optical properties tobe measured include
27、reflectance (brightness) as found in TestMethod D 985 and color according to TAPPI Standard T 524.If test results are different on one side versus the other, reportresults for each side separately.9.4 Conduct the test in a temperature and humidity con-trolled room that is maintained at 23C and 50 %
28、relativehumidity according to Practice D 685.9.5 Cut test specimens to a size that is the maximum thatwill fit in the available space provided in the selected testchamber, taking care to ensure that the specimen will beuniformly irradiated over its entire surface.9.6 Mount the specimens on the appro
29、priate surface of thetest chamber with clamps provided with the device. Take careto mount specimens of both sides of the paper for exposure.9.7 Expose three replicate specimens of each paper to betested to light from a xenon arc lamp controlled to 765 6 75W/m2as measured in the 290 to 800 nm wavelen
30、gth range.9.8 Expose the specimens for 48 6 0.5 h. Do not remove thespecimens from the chamber during the period of exposure.Remove the specimens from the test chamber at the end of theexposure at the same time of day at which the test was initiated.9.9 Immediately upon removal from the test chamber
31、,condition the exposed paper specimens in the dark for 24 haccording to Practice D 685.9.10 Immediately upon removal from the conditioning pro-cess, measure the optical properties of the exposed specimensonce again, taking care to again measure both sides of thepaper sheets. Report any differences t
32、hat exist between the twosides.9.11 Measure directional reflectance, R (brightness), accord-ing to Test Method D 985. Measure yellowness, b*, accordingto TAPPI T 524.10. Calculation and Interpretation of Results10.1 Calculate the percentage change in reflectance at 457nm (brightness) according to th
33、e following formula:% Change 5Ri2 RfRi3 100 (1)where:Ri= initial reflectance, andRf= final reflectance.10.2 Calculate the absolute change in yellowness accordingto the following formula:Change in yellowness, b* 5?b*f2 b*i?(2)where:b*f= final yellowness, andb*i= initial yellowness.D678902e2210.3 With
34、 regard to paper brightness (reflectance at 457 nm)stability, the following classes are specified:Stable #5 % reflectance lossModerately Stable 5 % and #20 % reflectance lossUnstable 20 % reflectance lossNOTE 1Papers in the “Moderately Stable” range may be fully stablefor some users. However, if a v
35、ery high level of optical stability isrequired, papers should be selected that meet the “Stable” criteria above.10.4 With regard to change of paper yellowness, the follow-ing classes are specified:Stable #3 points of absolute b* increaseModerately Stable 3 and #8 points of absolute b* increaseUnstab
36、le 8 points of absolute b* increaseNOTE 2If all that is desired is legibility of a printed text, paper canbecome significantly yellowed and still meet the requirements of the enduser, even though the changes in optical properties may position it in the“Unstable” category.11. Report11.1 Report the pe
37、rcent change in reflectance, R, (bright-ness) and the absolute change in yellowness (Db*). If there isa difference in these properties between the top and bottom sideof the paper, report each separately.11.2 From the change values and the classes of stabilitydefined in Section 10, report whether a t
38、ested specimen isjudged likely to be stable, moderately stable, or unstable interms of its optical properties when exposed to future naturallong-term aging experiences in which the paper is exposed toambient light sources.11.3 Report the type and manufacturer of the device usedfor exposure.11.4 Repo
39、rt the method utilized for cooling the papersurface, the temperature measured at the surface, and therelative humidity of the air above the surface being tested.11.5 If a much more thorough report of the test is desired,refer to Practice G 151 for a comprehensive list of parametersthat may be consid
40、ered for inclusion in the report.12. Precision and Bias12.1 PrecisionThe values of repeatability shown belowhave been calculated from test results, each of which is theaverage of three replicate test determinations. The values arebased on data obtained at the USDA Forest Products Labora-tory in Madi
41、son, WI during the research work that led todevelopment of this test method. An array of ten papers wastested. The fiber furnish components of the papers ranged fromacid stone groundwood to alkaline cotton fiber. The formationof all papers was somewhat poor and added to the variability ofthe test re
42、sults. In general, optically stable papers and thosewith better formation uniformity have the most repeatablemeasurements. Those that are poorly formed and are opticallyunstable have greater variability of measurements and arecalculated according to TAPPI T 1206.12.2 Repeatability = 0.39 absolute po
43、ints of b* with therange of repeatability for all materials in the study extendingfrom 0.02 to 0.75 absolute points of b*.12.3 Repeatability = 1.893 percent of R (brightness) withthe range of repeatability for all materials in the studyextending from 0.033 to 4.838 percent of reflectance.12.4 Reprod
44、ucibility between laboratories awaits a roun-drobin program to be completed prior to the five-year reviewof this test method.12.5 BiasBias for this procedure cannot be determinedbecause no acceptable standard reference materials are avail-able. Since the measurement of properties is according tostan
45、dardized test procedures, refer to Test Method D 985 forreflectance (brightness) value bias and to TAPPI T 524 foryellowness information.13. Keywords13.1 accelerated light aging; directional reflectance; irradi-ance; Kubelka-Munk theory; light flux; optical permanence;optical properties; paper stabi
46、lity; photochemical reactions;xenon-arc; yellownessAPPENDIX(Nonmandatory Information)X1. ADDITIONAL INFORMATIONX1.1 Strength TestingX1.1.1 Very long-term continuous exposure to natural day-light and to common artificial light has been shown to causeloss of strength in uncoated papers regardless of t
47、heir fibercomposition.X1.1.2 The most sensitive test by which to measure physi-cal property loss is cellulose degree of polymerization (DP).This method has problems for use in a standard acceleratedlight aging test. DP can be approximated for lignin-free papersusing the well-established CED (cupriet
48、hylenediamine) test(TAPPI T 254). However, for lignin-containing papers, a spe-cial test that uses a process developed by the CanadianConservation Institute is required. This procedure calls forpartial removal of the lignin with a mild acid chlorite treatmentand then uses cadoxen instead of CED. Thi
49、s procedure isrequired to provide a reliable approximation of loss of DP inD678902e23lignin-containing papers. The cadoxen method is currentlyused in only a few laboratories and cannot be considered astandard method.6X1.2 Additional Useful InformationX1.2.1 Post Color Number (PC) change may be useful totrack. PC is calculated from Kubelka-Munk theory accordingto the following equations:k/s 5 1 2 R!2/2R(X1.1)andPC 5 100k/s!final2 k/s!initial# (X1.2)where:k = absorption coefficient,s = scattering coefficient, andR= reflectance at 457 nm for an “infinitely” thic
