1、Designation:D544017(Reapproved 2021)Standard Test Method forDetermining the Melting Point of Fats and Oils1This standard is issued under the fixed designation D5440;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last rev
2、ision.A number in 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 is intended to determine the meltingpoint of all normal animal and vegetable fats and oils.This testmethod was der
3、ived from ALCA H-16.1.2 The values stated in SI units are to be regarded asstandard.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 t
4、o establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Princi
5、ples for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:E2251 Specification for Liquid-in-Glass ASTM Thermom-eters with Low-Hazard Precision Liquids2.2 Amer
6、ican Leather Chemists Association Standard:ALCA H-16 Melting Point23.Significance and Use3.1 This test method is intended to determine the meltingpoint of all normal animal and vegetable fats.3.2 The natural fats and oils,that is,those of animal andvegetable origin,are mixtures of glycerides and oth
7、er sub-stances and consist of a number of components.They do notexhibit either a definite or sharp melting point.Fats passthrough a stage of gradual softening before they becomecompletely liquid.The melting point then shall be defined bythe specific conditions of the method by which it is determined
8、and,in this case,it shall be the temperature at which the samplebecomes perfectly clear and liquid.4.Apparatus4.1 Melting Point Tubes,capillary globe tubing,with aninside diameter of 1 mm and an outside diameter of 2 mm,max.A convenient length is 50 mm to 80 mm.4.2 Thermometer,2 C to 68 C with 0.2 C
9、 divisions(S12C or S15C)and conforming to the requirements prescribedin Specification E2251 for thermometers.4.3 Glass Beaker,600 mL.4.4 Heat Source,gas burner or electric hot plate.5.Procedure5.1 The sample shall be melted and filtered through filterpaper to remove any impurities and the last trace
10、s of moisture.The sample shall be absolutely dry.At least three cleancapillary tubes shall be dipped in the completely liquid sampleso that the fat stands approximately 10 mm high in each tube.One end of the tube(where the sample is located)shall befused in a small flame,taking care not to burn the
11、fat.5.2 The tubes shall be placed in a beaker and held in arefrigerator at 4 C to 10 C overnight(16 h).5.2.1 The samples shall be completely liquid when the tubesare placed in the refrigerator.It is good practice to pass theends of the tubes containing the sample momentarily throughthe flame,just be
12、fore they are taken to the refrigerator.5.3 After removing the tubes from the refrigerator,theyshall be attached to the thermometer,using a rubber band orany suitable means,so that the lower ends of the melting pointtubes shall be even with the bottom of the mercury bulb of thethermometer.The thermo
13、meter shall be suspended in a 600 mLbeaker,which is about half full of clear distilled water and thebottom of the thermometer immersed approximately 30 mm.5.4 The starting bath temperature shall be adjusted to 8 Cto 10 C below the melting point of the sample at the beginningof the test.Agitation of
14、the water bath shall be made with asmall stream of air or other suitable means,and heat shall beapplied so the batch temperature is increased at the rate ofapproximately 0.5 C per min.1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subc
15、ommittee D31.08 on Fats and OilsCurrent edition approved Dec.1,2021.Published January 2022.Originallyapproved in 1993.Last previous edition approved in 2017 as D5440 17.DOI:10.1520/D5440-17R21.2Available from American Leather Chemists Assn.,Texas Tech University,P.O.Box 45300,Lubbock,TX 79409.Copyri
16、ght ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1?5.5 Fats usually pass through an opalescent stage beforemelting completely.The hea