1、Designation: D 1746 03Standard 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 (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. Scope*1.1 This test method covers the measurement of the trans-parency of pla
3、stic 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 br
4、ackets are for information only.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 limitati
5、ons 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:D 618 Practice for Conditioning Plastics for Testing2D 883 Terminology Relating to Plastics2D 1003 Test Method
6、for Haze and Luminous Transmittanceof Transparent Plastics2E 284 Terminology of Appearance3E 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method4E 1164 Practice for Obtaining Spectrophotometric Data forObject-Color Evaluation3E 1316 Terminology for Nondest
7、ructive Examinations5E 1345 Practice for Reducing the Effect of Variability ofColor Measurement by Use of Multiple Measurements3E 1347 Test Method for Color and Color-Difference Mea-surement by Tristimulus (Filter) Colorimetry3E 1348 Test Method for Transmittance and Color by Spec-trophotometry Usin
8、g Hemispherical Geometry33. 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 r
9、egulartransmittance. Sensitivity 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 trans
10、parency ofabout 10 to 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
11、in comparingresults obtained 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
12、 on an observers ability 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,
13、 receptor aperture,photoelectric detector, and an indicating or recording system,arranged to measure regular transmittance. The system shallmeet the following requirements:5.1.1 An incandescent or vapor-arc lamp, with a regulatedpower supply such that fluctuations in light intensity shall beless tha
14、n 61 %. If an arc lamp is used, an appropriate filtershall be used to limit light only to the spectral range from 540to 560 nm.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 ap
15、proved July 10, 2003. Published September 2003. Originallyapproved in 1960. Last previous edition approved in 1997 as D 1746 97.2Annual Book of ASTM Standards, Vol 08.01.3Annual Book of ASTM Standards, Vol 06.01.4Annual Book of ASTM Standards, Vol 14.02.5Annual Book of ASTM Standards, Vol 03.03.1*A
16、Summary 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.5.1.2 Asystem of apertures and lenses shall be used that willprovide a symmetrical incident beam. When measured with theind
17、icating 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 1000.05 100.1 10.3 0.1The source aperture may b
18、e 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. Provisionmust be made for rotating the specimen if s
19、lit 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. The image of the source aperturewith no spec
20、imen 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 uniform over the entirerange from the unobstruct
21、ed 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 apertures, in two direc-tions at right angles
22、 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 deviated by a specimen with nonparallelsurfaces.NOT
23、E 4Apparatus meeting these requirements has been described inthe literature,6and commercial versions are available.76. Reference Materials6.1 Since no regular transmittance standards are known tobe available, it is recommended that specimens of glass orother material believed to maintain constant li
24、ght 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 materials for checking for changesin instrumen
25、t 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 highly reflective materials may bemeasured b
26、y 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 prepared foreach material unless otherwise s
27、pecified 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. Conditioning8.1 ConditioningCondition the test sp
28、ecimens at 23 62C 73.4 6 3.6F and 50 6 5 % relative humidity for not lessthan 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 1.8Fand 62 % relative humidity.8.2 Test ConditionsCondu
29、ct tests in the standard labora-tory atmosphere of 23 6 2C 73.4 6 3.6F and 50 6 5%relative humidity, unless otherwise specified in the test meth-ods. In cases of disagreement, the tolerances shall be 1C1.8F and 62 % relative humidity.9. Instrument Adjustment9.1 Turn the instrument on and allow it to
30、 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 maximum intensity from the light. Either set thisvalue
31、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 light beam blocked at sample position, set thereading to ze
32、ro.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 thelight beam. Record the reading as Ir. Rotate the specimen 90to measure the directionality of the sp
33、ecimen 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).6Webber, Alfred C., “Method for the Measurement of Transparency of SheetMaterials,” Journal of the Optic
34、al Society of America, JOSAA, Vol 47, No. 9,September 1957, pp. 785789.7A Clarity Meter is available from Zebedee, P.O. Box 395, Landrum, SC 29356,(800)462-1804.D174603210.6 A test result is the mean of these three readings(minimum) for each angle of rotation. Report the results in oneof two ways: (
35、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 specimen in the beam.NOTE 6No calculation is
36、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-mittance (standard deviation of n readings/n1/
37、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 direction of testing,12.1.5 Standard deviation (
38、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 fourspecimens run on separate days, and each
39、 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 based on a round robin conducted in 1994,per
40、 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 materials using three differentold Gardn
41、er 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, SRis thebetween-laboratory reproducibili
42、ty 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 in Table 1 and Table 2 should not be app
43、lied 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 691 togenerate data specific to their la
44、boratory 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 day, the means should be judgednot equiva
45、lent 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 laboratories, the means should be judged no
46、tequivalent 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 determined since there is noaccepted refere
47、nce 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 OldGardner Clarity Meters, SummaryMaterial
48、 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
49、 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 photographic films, and C through F were packaging films.D1746033SUMMARY OF CHANGESThis section identifies the location of selected changes to this test method. For the convenience of the user,Committee D20 has highlighted those changes that may impact the use of this test method. This section may alsoinclude descriptions of the change
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