1、Designation: D1746 09D1746 15Standard Test Method forTransparency of Plastic Sheeting1This standard is issued under the fixed designation D1746; 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
2、 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 U.S. Department of Defense.1. Scope*1.1 This test method covers the measurement of the transparen
3、cy of plastic sheeting in terms of regular transmittance (Tr).Although generally applicable to any translucent or transparent material, it is principally intended for use with nominally clear andcolorless thin sheeting.1.2 The values stated in SI units are to be regarded as the standard. The values
4、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 health practices and determine the applicability of regula
5、torylimitations prior to use.NOTE 1There is no similar or equivalent ISO known ISO equivalent to this standard.NOTE 2For additional information, see Terminology E284 and Practice E1164.2. Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD883 Terminology Rela
6、ting to PlasticsD1003 Test Method for Haze and Luminous Transmittance of Transparent PlasticsE284 Terminology of AppearanceE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE1164 Practice for Obtaining Spectrometric Data for Object-Color EvaluationE1316
7、 Terminology for Nondestructive ExaminationsE1345 Practice for Reducing the Effect of Variability of Color Measurement by Use of Multiple MeasurementsE1347 Test Method for Color and Color-Difference Measurement by Tristimulus ColorimetryE1348 Test Method for Transmittance and Color by Spectrophotome
8、try Using Hemispherical Geometry3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method, refer to Terminologies D883, E284, and E1316.4. Significance and Use4.1 The attribute of clarity of a sheet, measured by its ability to transmit image-forming light, correlates with
9、 its regulartransmittance. Sensitivity to differences improves with decreasing incident beam- and receptor-angle. If the angular width of theincident beam and of the receptor aperture (as seen from the specimen position) are of the order of 0.1 or less, sheeting ofcommercial interest have a range of
10、 transparency of about 10 to 90 % as measured by this test. Results obtained by the use of thistest method are greatly influenced by the design parameters of the instruments; for example, the resolution is largely determinedby the angular width of the receptor aperture. Caution should therefore be e
11、xercised in comparing results obtained from differentinstruments, especially for samples with low regular transmittance.1 This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.40 on Optical Properties.Current edition approve
12、d Feb. 1, 2009April 1, 2015. Published March 2009April 2015. Originally approved in 1960. Last previous edition approved in 20032009 asD1746 03.D1746 09. DOI: 10.1520/D1746-09.10.1520/D1746-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at ser
13、viceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.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.
14、 Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section
15、appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 Regular transmittance data in accordance with this test method correlate with the property commonly known as“see-through,” which is rated subjectiv
16、ely by the effect of a hand-held specimen on an observers ability to distinguish clearly arelatively distant target.This correlation is poor for highly diffusing materials because of interference of scattered light in the visualtest.5. Apparatus5.1 The apparatus shall consist of a light source, sour
17、ce aperture, lens system, specimen holder, receptor aperture, photoelectricdetector, and an indicating or recording system, arranged to measure regular transmittance. The system shall meet the followingrequirements:5.1.1 An incandescent or vapor-arc lamp, with a regulated power supply such that fluc
18、tuations in light intensity shall be lessthan 61 %. If an arc lamp is used, an appropriate filter shall be used to limit light only to the spectral range from 540 to 560 nm.5.1.2 A system of apertures and lenses shall be used that will provide a symmetrical incident beam. When measured with theindic
19、ating or recording system of the apparatus, using a receptor aperture having a width or diameter subtending an angle of 0.0256 0.005 at the plane of the specimen, the incident beam shall meet the following requirements:Angle, Maximum RelativeIntensity0 1000.05 100.1 10.3 0.1The source aperture may b
20、e circular or a rectangular slit having a length-to-width ratio of at least 10.5.1.3 A holder shall be provided that will secure the specimen so that its plane is normal to the axis of the incident beam at afixed distance from the receptor aperture. Provision must be made for rotating the specimen i
21、f slit optics are used. Provision fortransverse motion may be provided to facilitate replication of measurements.5.1.4 An aperture shall be provided over the receptor so that its diameter or width subtends an angle, at the plane of thespecimen, of 0.1 6 0.025. The image of the source aperture with n
22、o specimen in place shall be the same shape as the receptoraperture centered on and entirely within it.5.1.5 A photoelectric detector shall be provided such that the indicated or recorded response to incident light shall besubstantially a linear function and uniform over the entire range from the un
23、obstructed beam (Io) to 0.01 Io or less.5.1.6 Means shall be provided for relatively displacing the receptor or the image of the source aperture (in the plane of thereceptor aperture) by at least 1 from the optical axis of the undeviated incident beam; for circular apertures, in two directions atrig
24、ht angles to each other; for slit optics, in the direction of the short dimension of the slit.NOTE 3This provision is necessary for checking the geometry of the incident beam (5.1.2) and for readjusting for maximum light intensity in theevent that the beam is deviated by a specimen with nonparallel
25、surfaces.NOTE 4Apparatus meeting these requirements has been described in the literature,3 and commercial versions are available.46. Reference Materials6.1 Since no regular transmittance standards are known to be available, it is recommended that specimens of glass or othermaterial believed to maint
26、ain material(s) maintaining constant light transmission properties with time be selected that yielddifferent regular transmittance values for use as reference materials.6.2 Measure the regular transmittance value of each specimen, and label it with the value obtained.6.3 Keep these reference materia
27、ls for checking forany changes in instrument performance in the future.over time.7. Test Specimens7.1 All specimens should preferably be nominally colorless (see Note 5) and transparent to translucent, have essentially planeparallel surfaces, and be free of surface or internal contamination.NOTE 5Tr
28、ansparency of colored or highly reflective materials may be measured by the ratio of Tr/Tt, where Tt is the total luminous transmittance(see Test Method D1003, E1347, or E1348).7.2 Nonrigid specimens must be held in a suitable holderAsuitable holder shall be used for nonrigid specimens so that they
29、areflat and free from wrinkles.7.3 A minimum of three test specimens shall be prepared for each material unless otherwise specified in the applicablematerialproduct specification. Practice E1345 provides procedures for reducing variability in test results to meet stated tolerancelimits by using meas
30、urements of multiple specimens (or multiple measurements on a single specimen).3 Webber, Alfred C., “Method for the Measurement of Transparency of Sheet Materials,” Journal of the Optical Society of America, JOSAA, Vol 47, No. 9, September1957, pp. 785789.4 The sole source of supply of the Clarity M
31、eter known to the committee at this time is Zebedee, P.O. Box 395, Landrum, SC 29356, (800)462-1804. (800) 462-1804.If you are aware of alternative suppliers, please provide this information toASTM International Headquarters. Your comments will receive careful consideration at a meetingof the respon
32、sible technical committee,1 which you may attend.D1746 152NOTE 6Practice E1345 provides procedures for reducing variability in test results to meet stated tolerance limits by using measurements of multiplespecimens (or multiple measurements on a single specimen).8. Conditioning8.1 ConditioningCondit
33、ion the test specimens at 23 6 2C (73.4 6 3.6F) and 50 6 10 % relative humidity for not less than40 h prior to test in accordance with ProcedureAof Practice D618 for those tests where conditioning is required. unless otherwisespecified by contract or the relevant ASTM material specification. In case
34、s of disagreement, the tolerances shall be 1C (1.8F)and 65 % relative humidity.8.2 Test ConditionsConduct the tests in the standard laboratory atmosphere of 23 6 2C (73.4 6 3.6F) and 50 6 10 %relative humidity,at the same temperature and humidity used for conditioning with tolerances in accordance w
35、ith Section 7 ofPractice D618, unless otherwise specified in the test methods. by contract or the relevant ASTM material specification. In casesof disagreement, the tolerances shall be 1C (1.8F) and 65 % relative humidity.9. Instrument Adjustment9.1 Turn the instrument on and allow it to come to a s
36、table operating temperature.9.2 With the light beam blocked at sample position, set the reading to zero.9.3 With the light beam unblocked, adjust the reading to a maximum by moving the receptor aperture so that the receptorreceives the maximum intensity from the light. Either set this value to 100 o
37、r record it as Io.9.4 Check for changes in instrument performance by reading the reference materials prepared in Section 6.10. Procedure10.1 Turn the instrument on and allow it to come to a stable operating temperature.10.2 With the light beam blocked at sample position, set the reading to zero.10.3
38、 With the light beam unblocked, set the reading to 100 and record it as Io.10.4 Mount a test specimen in the instrument so that it is neither wrinkled nor stretched, but centered and normal to the lightbeam. Record the reading as Ir. Rotate the specimen 90 to measure the directionality of the specim
39、en and record the reading asI90. 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).remaining specimens (minimum two).10.6 A test result is the mean of these three readings (minimum) for each
40、 angle of rotation. Report the results in one of twoways: (a) per direction or (b) averaged. Individual results must also be reported.11. Calculation11.1 Calculate the percent regular transmittance, Tr, as follows:Tr 5100Ir /Io (1)where:Ir = light intensity with the specimen in the beam, andIo = lig
41、ht intensity with no specimen in the beam.NOTE 7No calculation is needed if Io is set to 100 or a conversion chart or special scale is used to interpret the instrument reading.11.2 Calculate the test result or average transmittance of the three, or more, readings.11.3 Calculate the standard deviatio
42、n of the average transmittance (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 machine direction and 90 rotation or average of both directions,12.1.4 Number of
43、specimens tested and direction of testing,12.1.5 Standard deviation (see 11.3), and12.1.6 Any measured anisotropy.12.1.7 Temperature and humidity used for conditioning or testing if different from those cited in Section 8.13. Precision and Bias13.1 Precision:D1746 15313.1.1 Table 1 is based on a rou
44、nd robin conducted in 1987, per Practice E691, involving seven materials tested by sevenlaboratories. Each material tested was represented by four specimens run on separate days, and each specimen was evaluated induplicate in one day. This procedure yielded eight test results for each material under
45、 evaluation, from each laboratory. Theinstruments 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 Practice E691, involving six materials tested by ninelaboratories using Zebedee clarity meters. Four specimen
46、s of each material were measured in five places. The mean of the fivemeasurements on each specimen was considered a test result. Measurements of these materials using three different old Gardnerclarity meters yielded results consistent with those obtained with the Zebedee meters.13.1.3 Summary stati
47、stics are given in Table 1 and Table 2. In the tables, for the material indicated, Sr is the pooledwithin-laboratory standard deviation of a test result, SR is the between-laboratory reproducibility standard deviation of a test result,r = 2.83 Sr (see 13.1.4), and R = 2.83 SR. WarningThe following e
48、xplanations of r and R (13.1.3 13.1.6) are intended onlyto present a meaningful way of considering the approximate precision of this test method. The Do not apply the data in Table 1and Table 2 should not be applied rigorously to acceptance or rejection of material, as those data are specific to the
49、 round robinand may not be representative of other lots, conditions, materials, or laboratories. Users of this test method should need to applythe principles outlined in Practice E691 to generate data specific to their laboratory and materials, or between specific laboratories.The principles of 13.1.3 13.1.6 would then be valid for such data.13.1.4 RepeatabilityIn comparing two mean values for the same material, obtained by the same operator using the sameequipment on the same day, the means should be judged not equivalent if they differ b
