1、Designation: D3954 94 (Reapproved 2010)Standard Test Method forDropping Point of Waxes1This standard is issued under the fixed designation D3954; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number i
2、n parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the ASTMdropping point for waxes.1.2 The values stated in SI units are to be regarded asstandard.
3、No other units of measurement are included in thisstandard.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-bi
4、lity of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D566 Test Method for Dropping Point of LubricatingGrease3. Summary of Test Method3.1 In this test method, the dropping point is defined as thetemperature at which the wax suspended in a cylindrical cup,with a 2.8-
5、mm diameter hole in the bottom, flows downward adistance of 19 mm to interrupt a light beam as the sample isheated at a constant rate in air.4. Significance and Use4.1 Waxes do not go through a sharp solid-liquid phasechange when heated and therefore do not have a true meltingpoint. As the temperatu
6、re rises, waxes gradually soften orbecome less viscous. For this reason, the determination of thesoftening point must be made by an arbitrary but closelydefined method if test values are to be reproducible.4.2 This test is useful in determining the consistency ofwaxes, and as one element in establis
7、hing the uniformity ofshipments or source of supply.4.3 This test method has been found suitable for all types ofwaxes including paraffin, microcrystalline polyethylene, andnatural waxes.5. Apparatus5.1 Suitable apparatus that meets the requirements of 5.1.1,5.1.2, and 5.1.3 can be used to determine
8、 dropping points bythis test method. Instruments are available commercially3consisting of a control unit with a digital temperature recorder,matched furnace, sample cartridges, and accessories. Thecontrol unit automatically maintains the furnace temperatureand controls the heating rate with a precis
9、ion of 0.1C. Thedropping point is automatically recorded, and the furnaceheating program is turned off when the sample interrupts thelight beam and triggers the photocell detector.5.1.1 Control UnitThis unit shall provide a continuouslinear temperature control from 25 to 250C at a 2C/min rate.A digi
10、tal readout shall record the softening point with anaccuracy of 0.1C.5.1.2 Furnace UnitThis unit shall be capable of heating asample cup assembly as described in 5.1.3 at 2C 6 0.3C/minlinear rate from 25 to 250C. It shall include a sensing systemcapable of detecting the softening point with an accur
11、acy of0.1C.5.1.3 Sample Cup AssemblyA chromium-plated brass cupconforming to the dimensions shown in Test Method D566.Itshall be placed in an assembly so that the sample flows downa distance of 19 mm to interrupt a light beam to cause digitaldisplay of the softening point.6. Preparation of Sample6.1
12、 For waxes heat the sample to 15 to 20C above itsmelting point to form a pourable liquid. Place the sample cupson glass slides and pour the melted sample into the cup to alevel even with the upper rim of the cup. Allow the sample tostand at room temperature for 2 h before running.1This test method i
13、s under the jurisdiction ofASTM Committee D21 on Polishesand is the direct responsibility of Subcommittee D21.02 on Raw MaterialsCurrent edition approved May 1, 2010. Published May 2010. Originallyapproved in 1980. Last previous edition approved in 2004 as D3954 94 (2004).DOI: 10.1520/D3954-94R10.2F
14、or 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.3The sole source of supply of the apparatus known to the commit
15、tee at this timeis Mettler Instrument Corp., Princeton-Hightstown Road, Hightstown, NJ 08520. Ifyou are aware of alternative suppliers, please provide this information to ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical committ
16、ee,1which you may attend.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7. Preparation of Apparatus7.1 Ensure that the furnace unit and the sample cup assem-bly are clean and bright, since tarnished or dirty apparatus willchange the
17、 apparent dropping point. After each determination,check to see if the apparatus requires cleaning.NOTE 1It is advisable to keep the equipment covered when not in use.8. Procedure8.1 The procedure for measuring the dropping point ofwaxes with the Mettler instrument has been developed toduplicate the
18、 results obtained by Test Method D566.8.2 Preheat or cool the furnace unit to a temperature of 20 to25C less than the expected dropping point (Note 2)ofthesample and maintain at this temperature. Place the cartridgeassembly containing the sample in position in the furnace,taking care that the slits
19、for the light beam are properlypositioned. When the ready light becomes steady, indicatingthe sample and furnace have equilibrated at the presenttemperature, initiate the 2C/min heating rate by pressing theSTART LEVEL. Heating will then continue automatically untilthe drop point occurs and the dropp
20、ing point temperature isdisplayed on the digital readout.NOTE 2In the event of a dispute, the purchaser and the seller shouldagree on the exact starting temperature to be used.8.3 Immediately remove the cartridge assembly uponcompletion of the test. Check to determine if the sample haspassed the lig
21、ht beam slot and no pretrigger has occurred.Inspect the dropping point apparatus to be sure no dirt,particles, or residue remain.8.4 Clean the sample cups by placing them upside down ona hard surface and punching out the residue material. Use aspatula shaped to the contours of the cup, to remove the
22、remaining particles with a gentle twirling motion.9. Report9.1 Report the dropping point recorded on the digitalreadout to the nearest 0.1C. If converted to degrees Fahren-heit, report to the nearest 0.2F. Experience has indicated thatduplicate runs are not necessary. If a known error in experi-ment
23、al procedure is made, the result should be discarded and asecond run should be made.10. Precision10.1 The following criteria shall be used for judging theacceptability of results (95 % probability) for the Mettlerdropping point:10.1.1 RepeatabilityDuplicate results by the same opera-tor shall not be
24、 considered suspect unless they differ by morethan 0.5C.10.1.2 ReproducibilityThe results reported by each of twolaboratories shall not be considered suspect unless the reportedvalues differ by more than 1.5C.10.1.3 The procedure in this test method has no bias becausethe values derived for the drop
25、 point of waxes are defined onlyin terms of this test method.11. Keywords11.1 drop point; waxesASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determina
26、tion 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 technical committee and must be reviewed every five years andif not revised, either reapproved or with
27、drawn. 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 consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that you
28、r 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 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (sing
29、le 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/).D3954 94 (2010)2
