1、Designation: D 1746 09Standard Test Method forTransparency of Plastic Sheeting1This standard is issued under the fixed designation D 1746; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in paren
2、theses 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. Scope*1.1 This test method covers the measurement of the trans-parency of plas
3、tic sheeting in terms of regular transmittance(Tr). Although generally applicable to any translucent ortransparent material, it is principally intended for use withnominally clear and colorless thin sheeting.1.2 The values stated in SI units are to be regarded as thestandard. The values given in par
4、entheses 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 determine the applica-bility of regulatory limitat
5、ions prior to use.NOTE 1There is no similar or equivalent ISO standard.NOTE 2For additional information, see Terminology E 284 and Prac-tice E 1164.2. Referenced Documents2.1 ASTM Standards:2D 618 Practice for Conditioning Plastics for TestingD 883 Terminology Relating to PlasticsD 1003 Test Method
6、for Haze and Luminous Transmittanceof Transparent PlasticsE 284 Terminology of AppearanceE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE 1164 Practice for Obtaining Spectrometric Data forObject-Color EvaluationE 1316 Terminology for Nondestructive E
7、xaminationsE 1345 Practice for Reducing the Effect of Variability ofColor Measurement by Use of Multiple MeasurementsE 1347 Test Method for Color and Color-Difference Mea-surement by Tristimulus ColorimetryE 1348 Test Method for Transmittance and Color by Spec-trophotometry Using Hemispherical Geome
8、try3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method, referto Terminologies D 883, E 284, and E 1316.4. Significance and Use4.1 The attribute of clarity of a sheet, measured by its abilityto transmit image-forming light, correlates with its regulartransmittance. S
9、ensitivity to differences improves with de-creasing incident beam- and receptor-angle. If the angularwidth of the incident beam and of the receptor aperture (as seenfrom the specimen position) are of the order of 0.1 or less,sheeting of commercial interest have a range of transparency ofabout 10 to
10、90 % as measured by this test. Results obtained bythe use of this test method are greatly influenced by the designparameters of the instruments; for example, the resolution islargely determined by the angular width of the receptoraperture. Caution should therefore be exercised in comparingresults ob
11、tained from different instruments, especially forsamples with low regular transmittance.4.2 Regular transmittance data in accordance with this testmethod correlate with the property commonly known as“see-through,” which is rated subjectively by the effect of ahand-held specimen on an observers abili
12、ty to distinguishclearly a relatively distant target. This correlation is poor forhighly diffusing materials because of interference of scatteredlight in the visual test.5. Apparatus5.1 The apparatus shall consist of a light source, sourceaperture, lens system, specimen holder, receptor aperture,pho
13、toelectric detector, and an indicating or recording system,1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.40 on Optical Properties.Current edition approved Feb. 1, 2009. Published March 2009. Originallyapproved in 196
14、0. Last previous edition approved in 2003 as D 1746 03.2For referenced ASTM standards, visit the ASTM website, www.astm.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.1*A Su
15、mmary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.arranged to measure regular transmittance. The system shallmeet the following requirements:5.1.1 An incandescent or vapor-arc
16、 lamp, with a regulatedpower supply such that fluctuations in light intensity shall beless than 61 %. If an arc lamp is used, an appropriate filtershall be used to limit light only to the spectral range from 540to 560 nm.5.1.2 Asystem of apertures and lenses shall be used that willprovide a symmetri
17、cal incident beam. When measured with theindicating or recording system of the apparatus, using areceptor aperture having a width or diameter subtending anangle of 0.025 6 0.005 at the plane of the specimen, theincident beam shall meet the following requirements:Angle, Maximum RelativeIntensity0 100
18、0.05 100.1 10.3 0.1The source aperture may be circular or a rectangular slithaving a length-to-width ratio of at least 10.5.1.3 A holder shall be provided that will secure thespecimen so that its plane is normal to the axis of the incidentbeam at a fixed distance from the receptor aperture. Provisio
19、nmust be made for rotating the specimen if slit optics are used.Provision for transverse motion may be provided to facilitatereplication of measurements.5.1.4 An aperture shall be provided over the receptor so thatits diameter or width subtends an angle, at the plane of thespecimen, of 0.1 6 0.025.
20、The image of the source aperturewith no specimen in place shall be the same shape as thereceptor aperture centered on and entirely within it.5.1.5 A photoelectric detector shall be provided such thatthe indicated or recorded response to incident light shall besubstantially a linear function and unif
21、orm over the entirerange from the unobstructed beam (Io) to 0.01 Ioor less.5.1.6 Means shall be provided for relatively displacing thereceptor or the image of the source aperture (in the plane of thereceptor aperture) by at least 1 from the optical axis of theundeviated incident beam; for circular a
22、pertures, in two direc-tions at right angles to each other; for slit optics, in thedirection of the short dimension of the slit.NOTE 3This provision is necessary for checking the geometry of theincident beam (5.1.2) and for readjusting for maximum light intensity inthe event that the beam is deviate
23、d by a specimen with nonparallelsurfaces.NOTE 4Apparatus meeting these requirements has been described inthe literature,3and commercial versions are available.46. Reference Materials6.1 Since no regular transmittance standards are known tobe available, it is recommended that specimens of glass oroth
24、er material believed to maintain constant light transmissionproperties with time be selected that yield different regulartransmittance values for use as reference materials.6.2 Measure the regular transmittance value of each speci-men, and label it with the value obtained.6.3 Keep these reference ma
25、terials for checking for changesin instrument performance in the future.7. Test Specimens7.1 All specimens should be nominally colorless (Note 5)and transparent to translucent, have essentially plane parallelsurfaces, and be free of surface or internal contamination.NOTE 5Transparency of colored or
26、highly reflective materials may bemeasured by the ratio of Tr/Tt, where Ttis the total luminous transmittance(see Test Method D 1003, E 1347, or E 1348).7.2 Nonrigid specimens must be held in a suitable holder sothat they are flat and free from wrinkles.7.3 Aminimum of three test specimens shall be
27、prepared foreach material unless otherwise specified in the applicablematerial specification. Practice E 1345 provides procedures forreducing variability in test results to meet stated tolerancelimits by using measurements of multiple specimens (ormultiple measurements on a single specimen).8. Condi
28、tioning8.1 ConditioningCondition the test specimens at 23 62C (73.4 6 3.6F) and 50 6 10 % relative humidity for notless than 40 h prior to test in accordance with Procedure A ofPractice D 618 for those tests where conditioning is required.In cases of disagreement, the tolerances shall be 1C (1.8F)an
29、d 65 % relative humidity.8.2 Test ConditionsConduct tests in the standard labora-tory atmosphere of 23 6 2C (73.4 6 3.6F) and 50 6 10 %relative humidity, unless otherwise specified in the test meth-ods. In cases of disagreement, the tolerances shall be 1C(1.8F) and 65 % relative humidity.9. Instrume
30、nt Adjustment9.1 Turn the instrument on and allow it to come to a stableoperating temperature.9.2 With the light beam blocked at sample position, set thereading to zero.9.3 With the light beam unblocked, adjust the reading to amaximum by moving the receptor aperture so that the receptorreceives the
31、maximum intensity from the light. Either set thisvalue to 100 or record it as Io.9.4 Check for changes in instrument performance by read-ing the reference materials prepared in Section 6.10. Procedure10.1 Turn the instrument on and allow it to come to a stableoperating temperature.10.2 With the ligh
32、t beam blocked at sample position, set thereading to zero.10.3 With the light beam unblocked, set the reading to 100and record it as Io.10.4 Mount a test specimen in the instrument so that it isneither wrinkled nor stretched, but centered and normal to the3Webber, Alfred C., “Method for the Measurem
33、ent of Transparency of SheetMaterials,” Journal of the Optical Society of America, JOSAA, Vol 47, No. 9,September 1957, pp. 785789.4The sole source of supply of the Clarity Meter known to the committee at thistime is Zebedee, P.O. Box 395, Landrum, SC 29356, (800)462-1804. If you areaware of alterna
34、tive suppliers, please provide this information to ASTM Interna-tional Headquarters. Your comments will receive careful consideration at a meetingof the responsible technical committee,1which you may attend.D1746092light beam. Record the reading as Ir. Rotate the specimen 90to measure the directiona
35、lity of the specimen and record thereading as I90. If no directionality is detected in the specimen,then the test may be performed without the 90 rotation.10.5 Repeat 10.4 for the other two specimens (minimum).10.6 A test result is the mean of these three readings(minimum) for each angle of rotation
36、. Report the results in oneof two ways: (a) per direction or (b) averaged. Individualresults must also be reported.11. Calculation11.1 Calculate the percent regular transmittance, Tr,asfollows:Tr5 100Ir/Io(1)where:Ir= light intensity with the specimen in the beam, andIo= light intensity with no spec
37、imen in the beam.NOTE 6No calculation is needed if Iois set to 100 or a conversionchart or special scale is used to interpret the instrument reading.11.2 Calculate the test result or average transmittance of thethree, or more, readings.11.3 Calculate the standard deviation of the average trans-mitta
38、nce (standard deviation of n readings/n1/2).12. Report12.1 Report the following information:12.1.1 Sample designation,12.1.2 Instrument used,12.1.3 Average regular transmittance (see 11.2) in machinedirection and 90 rotation or average of both directions,12.1.4 Number of specimens tested and directi
39、on of testing,12.1.5 Standard deviation (see 11.3), and12.1.6 Any measured anisotropy.13. Precision and Bias13.1 Precision:13.1.1 Table 1 is based on a round robin conducted in 1987,per Practice E 691, involving seven materials tested by sevenlaboratories. Each material tested was represented by fou
40、rspecimens run on separate days, and each specimen wasevaluated in duplicate in one day. This procedure yielded eighttest results for each material under evaluation, from eachlaboratory. The instruments used were Gardner clarity meters,which are no longer commercially available.13.1.2 Table 2 is bas
41、ed on a round robin conducted in 1994,per Practice E 691, involving six materials tested by ninelaboratories using Zebedee clarity meters. Four specimens ofeach material were measured in five places. The mean of thefive measurements on each specimen was considered a testresult. Measurements of these
42、 materials using three differentold Gardner clarity meters yielded results consistent with thoseobtained with the Zebedee meters.13.1.3 Summary statistics are given in Table 1 and Table 2.In the tables, for the material indicated, Sris the pooledwithin-laboratory standard deviation of a test result,
43、 SRis thebetween-laboratory reproducibility standard deviation of a testresult, r = 2.83 3 Sr(see 13.1.4), and R = 2.83 3 SR.WarningThe following explanations of r and R (13.1.3-13.1.6) are intended only to present a meaningful way ofconsidering the approximate precision of this test method. Thedata
44、 in Table 1 and Table 2 should not be applied rigorously toacceptance or rejection of material, as those data are specific tothe round robin and may not be representative of other lots,conditions, materials, or laboratories. Users of this test methodshould apply the principles outlined in Practice E
45、 691 togenerate data specific to their laboratory and materials, orbetween specific laboratories. The principles of 13.1.3-13.1.6would then be valid for such data.13.1.4 RepeatabilityIn comparing two mean values forthe same material, obtained by the same operator using thesame equipment on the same
46、day, the means should be judgednot equivalent if they differ by more than the r value for thatmaterial.13.1.5 ReproducibilityIn comparing two mean values forthe same material obtained by different operators using differ-ent equipment on different days, either in the same laboratoryor in different la
47、boratories, the means should be judged notequivalent if they differ by more than the R value for thatmaterial.13.1.6 Judgments made as described in 13.1.4 and 13.1.5will be correct in approximately 95 % of such comparisons.13.1.7 For further information, see Practice E 691.13.2 BiasBias cannot be de
48、termined since there is noaccepted reference method for determining this property. Thereis no bias between the Zebedee and old Gardner clarity meters.14. Keywords14.1 clarity; plastic; regular transmittance; sheeting; trans-mittance; transparencyTABLE 1 Round Robin on Clarity or Transparency Using O
49、ldGardner Clarity Meters, SummaryMaterial DesignationAverageTransparencySrSRrR1 10.6 0.66 1.27 1.86 2.332 12.7 0.48 1.60 1.36 4.543 46.4 2.10 2.81 5.92 7.764 73.2 1.79 2.45 5.05 6.945 84.8 1.01 1.41 2.86 4.006 89.1 0.36 0.49 1.03 1.407 90.8 2.00 2.60 5.67 7.35TABLE 2 Round Robin on Clarity or Transparency UsingZebedee CL-100 Meter, Summary Expressed in PercentMaterialAAverage SSRrRE 21.21 0.98 1.24 2.74 3.47D 44.34 2.07 2.46 5.80 6.89C 57.62 2.38 2.38 6.66 6.66F 77.19 2.47 2.47 6.92 6.92A 89.9 0.14 0.22 0.39 0.62B 90.2 0.23 0.34 0.64 0.95AA and B were ph
