1、Designation: D5565 95 (Reapproved 2011)Standard Test Method forDetermination of the Solidification Point of Fatty AcidsContained in Animal, Marine, and Vegetable Fats and Oils1This standard is issued under the fixed designation D5565; the number immediately following the designation indicates the ye
2、ar oforiginal adoption or, in the case of 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.1. Scope1.1 This test method covers determination of the solidific
3、a-tion point of fatty acids contained in animal, marine, andvegetable fats and oils.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
4、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 prior to use. See 5.2 and 5.7 foradditional information.2. Significance and Use2.1 This test method is intended to cover
5、 determination ofthe solidification point of fatty acids contained in animal,marine, and vegetable fats and oils used in the softening andstuffing of leather, as well as those used in the manufacture ofproducts for such purpose.3. Apparatus3.1 Griffn Low-Form Beaker, 2-L capacity.3.2 Wide Mouth Bott
6、leCapacity of 450 mL, height of 190mm, and inside diameter of neck of 38 mm.3.3 Test TubesLength of 100 mm and diameter of 25 mm,with or without rim. These tubes may have an etched markextending around the tube at a distance of 57 mm from thebottom to show the height to which the tube is to be fille
7、d.3.4 Saponification VesselA750- or 1000-mL flask.3.5 Stirrer, 2- to 3-mm outside diameter, with one end bentin the form of a loop of 19-mm outside diameter. Glass,nichrome, stainless steel, or monel wire shall be used. Theupper end can be formed to accommodate hand stirring or forattachment to a me
8、chanical stirrer.3.6 Laboratory Thermometer, 0 to 150C.3.7 Titer Test ThermometerSpecifications for thermom-eter used in titer test determinations:3.7.1 TypeEtched stem glass.3.7.2 LiquidMercury.3.7.3 Filling Above LiquidEvacuated or nitrogen gas.3.7.4 Temperature Range2 to +68C.3.7.5 Subdivisions0.
9、2C.3.7.6 Total Length385 to 390 mm.3.7.7 Stem Diameter6 to 7 mm.3.7.8 Stem ConstructionPlain or lens front. The crosssection of the lens front type shall be such that it will passthrough an 8 mm ring gage but will not entera5mmslot gage.3.7.9 Bulb Diameter5.5 mm to not greater than that ofstem.3.7.1
10、0 Bulb Length15to25mm.3.7.11 Bulb ConstructionCorning normal or equally suit-able thermometric glass.3.7.12 Distance from Bottom of Bulb to 2 Mark50 to60 mm.3.7.13 Distance from 68 Mark to Top of Thermometer20to 35 mm.3.7.14 Length of Unchanged Capillary Between the HighestGraduation and the Expansi
11、on Chamber10 mm.3.7.15 Expansion ChamberTo permit heating to at least85C.3.7.16 Top FinishGlass ring.3.7.17 Longer Graduation LinesAt each 1 mark.3.7.18 GraduationsNumbered at zero and each multipleof 2.3.7.19 Immersion45 mm, a line shall be etched around thestem 45 mm from the bottom of the bulb.3.
12、7.20 Special Marking on ThermometerA.O.C.S. TiterTest.3.7.21 Maximum Scale Error Permitted at any Point0.2C.3.7.22 Marking on CaseA.O.C.S. Titer Test, 2 to +68in 0.2C.3.7.23 StandardizationThe thermometer shall be stan-dardized at the ice point and at intervals of approximately20C, for the condition
13、 of 45 mm immersion, and for anaverage stem temperature of the emergent mercury column of25C.1This test method is under the jurisdiction ofASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.08 on Fats and Oils. This testmethod was developed in cooperation with the Amer
14、ican Leather Chemists Assn.(Methods H 10 and H 17-1957).Current edition approved Jan. 1, 2011. Published March 2011. Originallyapproved in 1994. Last previous edition approved in 2006 as D5565 95(2006).DOI: 10.1520/D5565-95R11.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West C
15、onshohocken, PA 19428-2959, United States.3.8 Filter Paper, qualitative, rapid filtering grade.4. Reagents4.1 Glycerol-Caustic Solution, prepared by dissolving, withthe aid of heat, 250 g of solid potassium hydroxide in 1250 gof glycerin (dynamite or C. P. grade). To avoid foaming,heating shall not
16、exceed 135 to 145C. (Sodium hydroxide cannot be substituted for potassium hydroxide.)4.2 Sulfuric Acid, 30 % by weight.5. Procedure5.1 Preparation of the Fatty AcidsWeigh approximately110 g of glycerol-caustic solution into the saponification vesseland heat to 150C with stirring. Then add approximat
17、ely 50mL of oil or melted fat sample and reheat the whole to 140 to150C. A little additional solution may be necessary to ensurecomplete saponification in some cases.5.2 Continue stirring until the saponification is complete.(WarningDo not heat to above 150C.)5.2.1 (The committee has investigated a
18、number of tests forcomplete saponification, but none has been found up to thepresent time that is reliable under all circumstances. Familiar-ity with the changes that occur in the appearance and characterof the mass usually enables determination of the proper endpoint. Saponification is usually indi
19、cated by a change in theappearance of the mass and is often accompanied by anincrease in the viscosity, or thickening. When this occurs, thesolution thins out again after the reaction is complete andassumes a homogeneous appearance. The most common char-acteristic is that of soap bubbles forming and
20、 rising from thesurface. There are cases in which none of these criteria can bedepended on, so that considerable care must be exercised at alltimes to ensure complete saponification.)5.3 After cooling slightly, add 200 to 300 mL of distilledwater and stir and heat the mass well until the soap isdiss
21、olved. Then, with stirring, add 50 mL of dilute H2SO4andboil the whole until the fatty acids are melted completely andclear. Additional water may be added before or during boilingif desired.5.4 Remove the aqueous layer, containing the H2SO4, addwater again, and repeat boiling for 2 to 3 min or until
22、 the fattyacids are melted entirely and clear. Since acids of high meltingpoint fats are sometimes slow to melt and clear, inspect thefatty acid layer while it is quiet to ensure that all has melted.5.5 Remove the water again, and, if necessary, repeat thewashings described in 5.4 until the wash wat
23、er is neutral to amethyl orange indicator.5.6 Transfer the fatty acids to a filter paper carefully, so asnot to include any water. The filter paper may be supported ona small beaker without a funnel. The acids must remaincompletely melted until entirely filtered.5.7 After heating the filtered acids
24、on a hot plate to 130Cto remove traces of moisture, fill the titer test tube to a heightof 57 mm from the bottom. (WarningThe sample shall notbe held at 130C or reheated to this temperature more thanonce. If excessive moisture is present, the water shall beallowed to settle and the fatty acids decan
25、ted and then refilteredand reheated. The acids must be thoroughly dry.)5.8 Solidification of the Fatty AcidsAdjust the water bathto a temperature of 20 6 1C for all samples having titers of35C or higher, and 15 to 20C below the titer point for allsamples with titers below 35C.5.9 Place the test tube
26、s, containing the fatty acids, in thewater bath assembly. Insert the titer thermometer to theimmersion mark so that it will be equidistant from the sides ofthe tube. Stir, with the stirring rod in a vertical manner, at a rateof 100 complete up-and-down motions/min. (Stirring may beperformed mechanic
27、ally by attaching a small motor with asuitable speed-reducing mechanism to the stirring rod.) Thestirrer shall move through a vertical distance of approximately38 mm, with agitation starting while the temperature is at least10C above the titer point.5.10 Continue stirring at the directed rate until
28、the tempera-ture remains constant for 30 s or begins to rise in less than a30-s interval. Discontinue stirring immediately, remove or raisethe stirrer out of the sample, and observe the increase intemperature. The titer point is the highest temperature indi-cated by the thermometer during this rise.
29、 Expect duplicatedeterminations to agree within 0.2C.6. Report6.1 Report the results in degrees Centigrade or Fahrenheit.Reference this test method as the procedure used in the testreport.7. Precision and Bias7.1 This test method is adopted from the procedures of theAmerican Leather Chemists Associa
30、tion, where it has longbeen in use and was approved for publication before theinclusion of precision and bias statements was mandated. Theoriginal interlaboratory test data are no longer available. Theuser is cautioned to verify by the use of reference materials, ifavailable, that the precision and
31、bias (or reproducibility) of thistest method is adequate for the contemplated use.8. Keywords8.1 fat liquors; fatty acids; leather; solidification point; titertestD5565 95 (2011)2ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item me
32、ntionedin 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 technical committe
33、e 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 consideration at a meeti
34、ng 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 Barr Harbor Drive, PO
35、 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/).D5565 95 (2011)3
