1、Designation: D7735 111Standard Test Method forType A Durometer Hardness Testing of Road MarkingThermoplastic at Elevated Temperatures1This standard is issued under the fixed designation D7735; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTESection 6.4 was corrected editorially in January 2014.1. Scope1.1 This test method covers Type A Durome
3、ter hardness ofroad marking thermoplastic material at elevated temperatures.1.2 This test method is similar to Test Method D2240 forhardness with special attention given to keeping the tempera-ture of the test sample and instrument constant. Within thehighway materials community, it is sometimes kno
4、wn as“indentation resistance.”1.3 All materials, instruments or equipment used for thedetermination of temperature, hardness and time shall betraceable to National Institute of Standards and Technology orother internationally recognized organizations parallel in na-ture.1.4 The values stated in SI u
5、nits are to be regarded asstandard. The values given in parentheses are for informationonly.1.5 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
6、ices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D16 Terminology for Paint, Related Coatings, Materials, andApplicationsD2240 Test Method for Rubber PropertyDurometer Hard-nessD7307 Practice for Sampling of Thermoplastic Traffic
7、Mark-ing MaterialsD7308 Practice for Sample Preparation of ThermoplasticTraffic Marking MaterialsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 Definitions:3.1.
8、1 The terms and definitions in Terminology D16 applyto this method.3.1.2 hardness, advthe value of resistance of a smallpenetrating device. In the case of the Type A Durometer inaccordance with Test Method D2240, the presser foot/indentor(spherical to 0.79 6 0.03 mm or 0.03 6 0.001 in.) is connected
9、to a spring loaded to a total of 0.075 N/Durometer units at fulldeflection. For reading of Type A hardness the instrumentsscale reads from 0 to 100. Minimal deflection is 0 (softest) andmaximum is 100 (hardest).3.1.3 thermoplastic, ntraffic marking (same as 3.1.4).3.1.4 thermoplastic traffc markinga
10、 highly filled 100 %total solids highway marking system that when heated to amolten state can be extruded or sprayed onto a road surface andwhen cooled forms a solid durable delineator or road markingthermoplastic usually melted to 220C (425F).4. Summary of Test Method4.1 This method was developed t
11、o enable the testing ofhardness or indentation resistance of road marking thermoplas-tic material at ambient roadway/highway temperatures. Due tothe speed at which basic road marking thermoplastic cools,testing its hardness at elevated temperatures is difficult, even ata relatively low 46C (115F). E
12、xisting non-standard methodsare not consistent because they allow the samples to changetemperature during testing. By keeping both the test samplesand the hardness tester in a regulated environment before andduring testing, the results are much more repeatable within alaboratory. The goal for this m
13、ethod is to allow results fromthis test to be more reproducible from laboratory to laboratory.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.44 on Traffic Coatings.Current
14、 edition approved Nov. 1, 2011. Published December 2011. DOI:10.1520/7735-11E01.2For 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
15、onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 The methodology involves measuring the hardness ofroadmarking thermoplastic by keeping the test sample in theelevated temperature environment (a water bath) during
16、 thetesting process and using a Durometer that can be placed in thewater bath and function. This method could be performed in aglove box/oven if the door was not opened before or during thetesting.5. Significance and Use5.1 This method is based on the penetration of a specifictype of indentor when f
17、orced into the material under specifiedconditions. The indentation hardness is inversely related to thepenetration and is dependent on the elastic modulus, viscoelas-tic behavior of the material, geometry of the indentor, theapplied force and temperature at test. This test method isempirical and the
18、refore primarily for control purposes. Nosimple relationship exists between indentation hardness deter-mined by this test method and any fundamental property of thematerial tested.6. Apparatus6.1 Safety Glasses.6.2 Aluminum Pans (20 mL) or adequate size for tester base.6.3 A Hardness Tester Type A N
19、eedle-type Durometer inaccordance with Test Method D2240.6.4 Constant 1000 g Load Weight for Type A Durometer.6.5 OptionalTest Block Kit containing Type A Durometersamples with values traceable to an accredited calibrationlaboratory.6.6 Oven controllable to 46 6 1.0C (115 6 3.0F) (orwithin 2.5 % of
20、set point).6.7 Water Bath controllable to 46 6 1.0C (115 6 3.0F) (orwithin 2.5 % of set point).6.8 Digital Timer in seconds.7. Hazards7.1 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 esta
21、blish appro-priate safety and health practices and determine the applicabil-ity of regulatory limitations prior to use.8. Calibration and Standardization8.1 Calibration of the Type A hardness tester shall be doneregularly by following the manufacturers recommendationsand following the Calibration se
22、ction of Test Method D2240.The test block kit can be used to verify that the instrument isworking properly.9. Procedure9.1 Sample the road marking thermoplastic in accordancewith Practice D7307 then begin preparation of samples inaccordance with Practice D7308.9.2 Pour thermoplastic that has been he
23、ated to 425F (or permanufacturers recommendation) into a 20 mL aluminum panto approximately half full, and then allow cooling to roomtemperature.9.3 Turn on heater on water bath and allow the temperatureto stabilize to 46 6 1.0C (115 6 3.0F) or as agreed upon bythe involved parties9.4 Turn on oven s
24、et to 46 6 1.0C (115 6 3.0F) or asmutually agreed upon by the involved parties and place theType A Durometer insideNOTE 1A bath or oven operated outside the recommended tempera-ture control may result in greater result variability.9.4.1 Other temperatures can be used when agreed uponbetween the part
25、ies involved.9.5 Place cooled hardness sample in water bath and turn onoscillator or stirrer.9.6 Samples should be allowed to equilibrate to the requiredtemperature for at least one hour before being tested. Samplesshould be tested within three hours of being in the water. Whenall samples and testin
26、g equipment have stabilized to the settemperature, testing can begin.9.7 Before testing sample, remove lid from water bath andturn off oscillator or stirrer. Quickly place hardness tester fromoven in water bath making sure that the needle point andbottom of weight is below the waterline. This will e
27、nsure thattester is exactly the same temperature as sample. If the tester isremoved from the water during the testing process, its tem-perature will change and cause variations in results. Sample(s)can be tested multiple times as long as sample and testerbottom are not removed from water during test
28、ing.9.8 To test sample, set timer so that a fifteen secondcountdown will begin. Place hardness tester over samplekeeping both under water at all times.9.9 Lower the hardness tester over the center of the testsample. As soon as contact is made, start timer and releasetester. The tester dial should mo
29、ve constantly lower. Whenfifteen seconds is reached, note the Type A hardness value onthe dial and record. Make at least two readings then average.Caution should be taken when making multiple readings not totest in the same spot or after the tester has been removed fromthe water.9.10 Care should be
30、taken to ensure that the force is appliedvertically to the indenter tip, as lateral force will cause errors incalibration.9.11 If sample fails, another reading may be takenimmediately, but do not place needle point in the sameindentation.10. Report10.1 Hardness measurements and average (Type A).10.1
31、.1 Date of testing.10.1.2 Oven and water bath temperature.10.1.3 Manufacturer, type and serial number of the Durom-eter.10.1.4 Date of last calibration and calibration due date.D7735 111211. Precision and Bias311.1 The precision of this test method is based on anInterlaboratory study of ASTM D7735 S
32、tandard Test Methodfor Hardness of Road Marking Thermoplastics, conducted in2010. A single laboratory, with three technicians, participatedin this study. Each of the technicians tested two differentmaterials a total of twelve times over a period of two days.Every “test result” reported represents an
33、 individual determi-nation. Except for the use of only a single laboratory, PracticeE691 was followed for the design and analysis of the data; thedetails are given inASTM Research Report No. RR:D01-1160.11.1.1 Repeatability Limit (r)Two test results obtainedwithin one laboratory shall be judged not
34、equivalent if theydiffer by more than the “r” value for that material; “r”istheinterval representing the critical difference between two testresults for the same material, obtained by the same operatorusing the same equipment on the same day in the samelaboratory.11.1.2 Repeatability limits are list
35、ed in Table 1 and Table 2.11.1.3 Repeatability Limit (R)Two test results shall bejudged not equivalent if they differ by more than the “R” valuefor that material; “R” is the interval representing the criticaldifference between two test results for the same material,obtained by different operators us
36、ing different equipment indifferent laboratories.11.1.4 In this study, since three different technicians in asingle laboratory performed the analyses, only modified repro-ducibility limits can be listed in Table 1 and Table 2.11.1.5 The reproducibility limit mentioned above is notused as specified i
37、n Practice E177, as it represents theanticipated variability between technicians in the same labora-tory.11.1.5.1 Any judgment in accordance with statements11.1.1 and 11.1.3 would normally have an approximate 95 %probability of being correct, however the precision statisticsobtained in this ILS must
38、 not be treated as exact mathematicalquantities which are applicable to all circumstances and uses.The limited number of materials tested and laboratories report-ing results guarantees that there will be times when differencesgreater than predicted by the ILS results will arise, sometimeswith consid
39、erably greater or smaller frequency that the 95 %probability limit would imply. The repeatability limit and thereproducibility limit should be considered as general guides,and the associated probability of 95 % as only a roughindicator of what can be expected.11.2 BiasAt the time of the study, there
40、 was no acceptedreference material suitable for determining the bias for this testmethod, therefore no statement on bias is being made.11.3 The precision statement was determined through sta-tistical examination of 72 results, from one laboratory, on twomaterials.11.4 To judge the equivalency of two
41、 test results, it isrecommended to choose the marking material closest incharacteristics to the test material.3Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D01-1160. ContactASTM CustomerService at serviceastm.org.TABLE 1 Hardn
42、ess Day 1 (Type A units)Material AverageARepeatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReprocucibilityLimitxsrSRrRWhite AlkydExtrude RoadMarkingThermoplastic46.06 2.29 2.36 6.42 6.60Yellow AlkydExtrude RoadMarkingThermoplastic54.83 2.04 2.08 5.70 5.82AThe average of
43、 the technicians calculated averages.TABLE 2 Hardness Day 2 (Type A units)Material AverageARepeatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReprocucibilityLimitxsrSRrRWhite AlkydExtrude RoadMarkingThermoplastic42.00 1.81 2.61 5.06 7.30Yellow AlkydExtrude RoadMarkingThe
44、rmoplastic49.89 2.32 2.32 6.51 6.51AThe average of the technicians calculated averages.D7735 111312. Keywords12.1 Durometer; hardness; indentation; indentation hard-ness; road marking thermoplasticASTM International takes no position respecting the validity of any patent rights asserted in connectio
45、n with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible
46、technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consid
47、eration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Bar
48、r Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D7735 1114
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