1、Designation: D 1386 98 (Reapproved 2004)Standard Test Method forAcid Number (Empirical) of Synthetic and Natural Waxes1This standard is issued under the fixed designation D 1386; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the acidnumber of synthetic waxes and natural waxes. The number
3、isobtained by direct titration of the material and indicates theamount of free acid present.1.2 This test method, using an ethanol-xylene mixture, isapplicable to all natural waxes, including carnauba. The testmethod is also applicable to oxidized microcrystalline waxes,oxidized Fischer-Tropsch, oxi
4、dized polyethylene, and montanesters.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 lim
5、itations prior to use.2. Referenced Document2.1 ASTM Standards:2E 200 Practice for Preparation, Standardization, and Stor-age of Standard and Reagent Solutions for ChemicalAnalysis3. Terminology3.1 Definition:3.1.1 acid number or acid valuethe number of milligramsof potassium hydroxide necessary to
6、neutralize1gofthesample.4. Significance and Use4.1 This test method is used to determine the property ofacid functionality. Acid functionality determines the utility ofthe wax as well as being a significant Quality Control test.5. Apparatus5.1 Analytical Balance.5.2 Buret, 50-mL, with 0.1-mL graduat
7、ions.5.3 Flasks, acid value, 250-mL.6. Reagents and Materials6.1 Purity of ReagentsReagent-grade chemicals orequivalent, as specified in Practice E 200, shall be used in alltests.6.2 Ethanolic Potassium Hydroxide, Standard Solution (0.1N)Dissolve 6.6 g of potassium hydroxide in 5.6 g of distilledwat
8、er. Dilute with USSD3A denatured ethanol or 95 % ethanolto 1000 mL. Standardize with 0.1 N hydrochloric acid.6.3 Phenolphthalein Indicator Solution (10 g/litre)Dissolve1gofphenolphthalein in 100 mL of USSD3A,denatured ethanol or 95 % ethanol.6.4 Xylene.7. Procedure7.1 Transfer 1 to2gofthesample, wei
9、ghed to the nearest0.001 g, to a 250-mL acid-value flask. Add 40 mL of xylene.Heat on a hot plate or water bath to put the sample intosolution. Occasional swirling may be necessary.7.2 Add 3 to 5 drops of phenolphthalein indicator solutionand titrate the hot solution to the first persistent pink col
10、or. Theend point is taken when the pink color remains for at least 10s. Swirl the flask vigorously during the titration. If precipitationof waxes occurs during titration, reheat the sample. Thetitration should be carried out as quickly as possible. Recordthe number of millilitres of standard alkali
11、solution used.NOTE 1Caution: To avoid saponification, do not reheat the solutionduring this operation.8. Calculation8.1 Calculate the acid number as follows:Acid number5AN356.1!/BA = millilitres of alkali solution required for titration of thesample,N = normality of the alkali solution, andB = grams
12、 of sample used.9. Precision and Bias9.1 PrecisionDuplicate results by the same operator shallnot be considered suspect unless the results are greater than astandard deviation of 0.8.1This test method is under the jurisdiction of ASTM Committee D21 on Polishesand is the direct responsibility of Subc
13、ommittee D21.02 on Raw Materials.Current edition approved Sept. 1, 2004. Published September 2004. Originallyapproved in 1955 as D 1386 55 T. Last previous edition approved in 1998 asD 1386 98.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at se
14、rviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.9.2 BiasThis test has no bias because the values prod
15、ucedare defined only in terms of this test method.10. Keywords10.1 acid number; free acid; natural waxes; polish; syntheticwaxes; titration; waxesASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of
16、 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 committee and must be reviewed every five
17、 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 meeting of theresponsible technical co
18、mmittee, 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 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).D 1386 98 (2004)2
