ASTM D87-2007a Standard Test Method for Melting Point of Petroleum Wax (Cooling Curve)《石蜡熔点的标准试验方法(冷却曲线)》.pdf

1、Designation: D 87 07aDesignation: 55/77(83)An American National StandardTechnical Association of Pulpand Paper IndustryStandard Method T 630m-61Method 1402-Federal TestMethod Standard No. 791bBritish Standard 4695Standard Test Method forMelting Point of Petroleum Wax (Cooling Curve)1This standard is

2、 issued under the fixed designation D 87; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon (e) indicates an editorial cha

3、nge since the last revision or reapproval.1. Scope*1.1 This test method covers the determination of the meltingpoint (cooling curve) of petroleum wax. It is unsuitable forwaxes of the petrolatum group, microcrystalline waxes, orblends of such waxes with paraffin wax or scale wax.NOTE 1For additional

4、 methods used for testing petroleum waxes, seeTest Method D 127 and Test Method D 938. Results may differ, dependingon the method used. For pharmaceutical petrolatum, Test Method D 127usually is used.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses

5、 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 limitations pri

6、or to use.2. Referenced Documents2.1 ASTM Standards:2D 127 Test Method for Drop Melting Point of PetroleumWax, Including PetrolatumD 938 Test Method for Congealing Point of PetroleumWaxes, Including PetrolatumD 6299 Practice for Applying Statistical Quality AssuranceTechniques to Evaluate Analytical

7、 Measurement SystemPerformanceE1 Specification for ASTM Liquid-in-Glass Thermometers3. Terminology3.1 Definitions:3.1.1 melting point (cooling curve) of petroleum waxtemperature at which melted petroleum wax first shows aminimum rate of temperature change when allowed to coolunder prescribed conditi

8、ons.3.1.1.1 DiscussionThe so-called “American MeltingPoint” is arbitrarily 1.65C (3F) above the Melting Point(Cooling Curve) of Petroleum Wax.4. Summary of Test Method4.1 In Procedure A (Manual Method), a specimen of moltenwax in a test tube fitted with a thermometer is placed in an airbath, which i

9、n turn is surrounded by a water bath held at 16 to28C (60 to 80F). As the molten wax cools, periodic readingsof its temperature are taken. When solidification of the waxoccurs, the rate of temperature decreases, yielding a plateau inthe cooling curve. The temperature at that point is recorded asthe

10、melting point (cooling curve) of the sample.4.2 In Procedure B, an automatic analyzer is used. As themolten wax cools, the sample temperature decrease is mea-sured every 15 s in 0.01C (0.1F) readings. The melting pointis considered reached when five consecutive measurements areconstant within a give

11、n temperature interval, usually 0.1C(0.2F).5. Significance and Use5.1 Melting point (cooling curve) is a test that is widelyused by wax suppliers and consumers. it is particularly appliedto petroleum waxes that are rather highly paraffinic or crystal-line in nature. A plateau occurs with specimens c

12、ontainingappreciable amounts of hydrocarbons that crystallize at thesame temperature, giving up heat of fusion, thus temporarilyretarding the cooling rate. In general, petroleum waxes withlarge amounts of non-normal hydrocarbons or with amorphoussolid forms will not show the plateau.6. Apparatus6.1

13、The necessary apparatus for Procedure A is described inAnnex A1.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.10.0A on Physical/Chemical Properties.In the IP, this test method is under the jur

14、isdiction of the StandardizationCommittee. This test method was adopted as a joint ASTM-IP standard in 1966.Current edition approved Nov. 1, 2007. Published November 2007. Originallyapproved in 1921. Last previous edition approved in 2007 as D 8707.2For referenced ASTM standards, visit the ASTM webs

15、ite, 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 Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor

16、 Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.2 The automatic instrument consists of a bath (for ex-ample, an aluminum block with two measuring locations, twoapertures to place the test tubes, and two apertures for thetemperature probes). The apparatus may have an accessoryd

17、igital display and a printer.6.2.1 The temperature of the bath is maintained between 22and 26C (72 and 79F). A heating device is used to increasethe temperature, and a cooling device with cold water circula-tion is used to decrease the temperature.6.2.2 The temperature may be monitored with a calibr

18、atedthermometer or an electronic temperature measuring device ofequivalent precision and accuracy.6.3 Other types of equivalent automatic apparatus are ac-ceptable.7. Test Specimen7.1 Obtain a sample of wax representative of the shipmentto be tested. From each test unit obtain a portion of waxweighi

19、ng at least 25 g for each melting point determination.8. Procedure A (Manual Method)8.1 Support the air bath in its proper position in the waterbath. Fill the water bath to within 13 mm (12 in.) of the top withwater at a temperature of 16 to 28C (60 to 80F). The bathtemperature is kept within these

20、limits throughout the test.8.2 Heat the wax sample to at least 8C (15F) above itsexpected melting point (see Note 2). To heat the wax sampleuse a suitable container in an oven or water bath which is heldat a temperature not exceeding 93C (200F). Avoid the use ofdirect heat such as flame or hot plate

21、. Do not keep the samplein the molten state longer than 1 h.NOTE 2If no estimate of the melting point is available, heat the waxsample to 10C (15F) above the temperature at which the wax iscompletely molten, or to from 90 to 93C (195 to 200F) beforeproceeding to the next step.8.3 Fill the test tube

22、to a height of 51 mm (2 in.) with themelted sample. Insert the melting point thermometer throughthe center of a one-holed stopper, such as a cork so that the79-mm (318-in.) immersion line is at the lower surface of thestopper. Insert the stopper into the test tube so that the bottomof the thermomete

23、r bulb is 10 mm (38 in.) from the bottom ofthe test tube. Support the test tube assembly in the air bath, asshown in Fig. A1.1, while the temperature of the molten wax isstill at least 8C (15F) above its expected melting point (Note2).8.4 Read the melting point thermometer every 15 s. Recordeach rea

24、ding to the nearest estimated 0.05C (0.1F). Observethe progress of these sequential readings to determine theappearance of the plateau. Identify the plateau as the first fiveconsecutive readings all of which agree within 0.1C (0.2F).Discontinue the test after obtaining these five plateau readings.NO

25、TE 3If no plateau appears as defined above, the reading procedureis continued until either (1) the temperature reached 38C (100F) or (2)the temperature reaches a point 8C (15F) below a temperature where thewax has solidified (as may be observed through a transparent bath). Ineither of these cases th

26、e test is discontinued and the method is judged NotApplicable to the sample (see Note 1 for other methods).9. Procedure B (Automatic Method)9.1 Place a clean test tube held in a PTFE holder ring in theaperture provided in the apparatus.9.2 Insert the temperature probe into a centrally bored,one-hole

27、d stopper, and insert it in the test tube. Check theprobe height to reach manufacturers suggested height. Placethe stopper with the probe back in the resting holder provided.9.3 Bring the sample to a temperature at least 8C (15F)above the expected melting point. Heat the sample in a 93C(200F) maximu

28、m temperature water bath.9.4 Add the molten sample to the test tube to the fillingmark. Place the stopper with the probe on the test tubeassembly.9.5 Insert the assembly into the aluminum block aperture,and initiate the analysis in accordance with the manufacturersinstructions.9.6 When the melting p

29、oint is detected, the analysis willautomatically stop. Per available options on the instrument, theresulting melting point will be displayed on the digital monitor,or printed on a printer, or both.10. Calculation and Report10.1 When using a manual apparatus, average the first fiveconsecutive thermom

30、eter readings of the identified plateau,which agree within 0.1C (0.2F). Correct this average forerror in the thermometer scale where necessary.10.2 The automatic apparatus will average the first fiveconsecutive temperature probe readings within 60.1C(60.2F).10.3 Report the result to the nearest 0.05

31、C (0.1F) as thePetroleum Wax Melting Point (Cooling Curve), Test MethodD 87. Also report whether the test was performed manually orusing automatic apparatus, as applicable.11. Quality Control (QC)11.1 Confirm the performance of the instrument or the testprocedure by analyzing a quality control (QC)

32、sample.11.1.1 When QC/Quality Assurance (QA) protocols arealready established in the testing facility, these may be usedwhen they confirm the reliability of the test result.11.1.2 When there is no QC/QA protocol established in thetesting facility, Appendix X1 can be used as the QC/QAsystem.12. Preci

33、sion and Bias312.1 PrecisionThe precision of this test method as deter-mined by statistical examination of interlaboratory results is asfollows:12.1.1 RepeatabilityThe difference between two test re-sults, obtained by the same operator with the same apparatusunder constant operating conditions on id

34、entical test material,would in the long run, in the normal and correct operation ofthe test method, exceed the following values only in one casein twenty:3Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D02-1617.D8707a2Manual ap

35、paratus 0.11CAutomatic apparatus 0.23C12.1.2 ReproducibilityThe difference between two singleand independent results obtained by different operators work-ing in different laboratories on identical test material would, inthe long run, in the normal and correct operation of the testmethod, exceed the

36、following values only in one case intwenty:Manual apparatus 0.41CAutomatic apparatus 0.50C12.2 This test method is considered suitable for waxes of amelting point between 38C (100F) and 82C (180F). Theseprecision values have been obtained by statistical examinationof interlaboratory test results fro

37、m 2005. These values arebased on a study among 14 laboratories, using seven paraffinwaxes with a melting point range of 52 to 70C (126 to 158F).12.3 BiasThe bias of this test method cannot be deter-mined since no generally acceptable standard reference mate-rial is available for this analysis.12.4 R

38、elative BiasThe sample set was analyzed usingboth manual and automatic apparatus. The difference betweenthe two sets of measurements was not very significant. Auto-matic mode results were biased very slightly low (averaging0.064 difference).12.4.1 Based on the comparison of analysis of three sets of

39、wax samples in the melting point range of 115 to 159F (a totalof 70 data points by each method) by both manual andautomatic apparatus in one laboratory, a correlation coefficientof r2of 0.9999 was obtained indicating that there is no biasbetween the two modes of measurement.13. Keywords13.1 cooling

40、curve; melting point; petroleum wax; waxANNEX(Mandatory Information)A1. APPARATUSA1.1 Test TubeA standard glass test tube, 25 mm (1 in.)in outside diameter, and 100 mm (4 in.) in length. It may bemarked with a reference line for sample filling at 51 mm (2 in.)above the bottom, and a reference line f

41、or positioning of thebottom of the thermometer at 10 mm (38 in.) above the bottom.A1.2 Air BathAcylinder 51 mm (2 in.) in inside diameterand114mm(412 in.) in depth, equipped to hold the test tubefirmly in a vertical position in the center of the air bath. Asexamples, a tight-fitting cork having a ce

42、ntral opening or ametal plate top with a spring clamp that holds the test tubefirmly in place have been found suitable to use.A1.3 Water BathA suitable cylindrical vessel, 130 mm(518 in.) in inside diameter and 152 mm (6 in.) in depth.Provide a fitted cover equipped to support the air bathvertically

43、 so that the sides and bottom of the air bath aresurrounded by a layer of water 38 mm (112 in.) thick. Providethe cover with an opening through which the bath thermometermay be suspended 19 mm (34 in.) from the outside wall of thewater bath.NOTE A1.1The air bath, water bath, and water bath cover may

44、 bemade in one assembly as shown in Fig. A1.1.A1.4 Melting Point ThermometerA wax melting pointthermometer having the range shown below and conforming tothe requirements as prescribed in Specification E1or in thespecifications for IP thermometers:Thermometer NumberTemperature Range ASTM IP38 to 82C

45、14C 17C100 to 180F 14F 17FNOTE A1.2Other means of monitoring the temperature (for example,a resistance temperature detector, in conjunction with a data logger orcomputer) may be used in place of the specified melting point thermom-eter, provided that the results are found to be statistically equival

46、ent andthat the laboratory making the substitution has collected the necessary datato demonstrate this equivalency.A1.5 Bath ThermometerAny suitable partial immersionthermometer, accurate to 1.0C (2F) throughout the requiredrange.A1.6 TimerInterval timer or stop watch.D8707a3APPENDIX(Nonmandatory In

47、formation)X1. QUALITY CONTROL MONITORINGX1.1 Confirm the performance of the instrument or the testprocedure by analyzing a quality control (QC) sample(s).X1.2 Prior to monitoring the measurement process, the userof the method needs to determine the average value and controllimits of the QC sample (s

48、ee Practice D 6299 and MNL74).X1.3 Record the QC results and analyze by control chartsor other statistically equivalent techniques to ascertain thestatistical control status of the total testing process (see PracticeD 6299 and MNL74). (In the absence of explicit requirementsgiven in the test method,

49、 this clause provides guidance on QCtesting frequency.) Investigate any out of control data for rootcause(s). The results of this investigation may, but not neces-sarily, result in instrument recalibration.X1.4 The frequency of QC testing is dependent on thecriticality of the quality being measured, the demonstratedstability of the testing process, and customer requirements.Generally, a QC sample should be analyzed each testing daywith routine samples. The QC frequency should be increased ifa large numb