1、Designation: D1386 10Standard Test Method forAcid Number (Empirical) of Synthetic and Natural Waxes1This standard is issued under the fixed designation D1386; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisio
2、n. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method covers the determination of the
3、acidnumber of synthetic waxes and natural waxes. The number 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 o
4、xidized microcrystalline waxes,oxidized Fischer-Tropsch, oxidized polyethylene, and montanesters.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns, if any
5、, 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 prior to use.2. Referenced Document2.1 ASTM Standards:2E200 Practice for Preparation, Standardization, and
6、Storageof Standard and Reagent Solutions for Chemical Analysis3. Terminology3.1 Definition:3.1.1 acid number or acid valuethe number of milligramsof potassium hydroxide necessary to neutralize1gofthesample.4. Significance and Use4.1 This test method is used to determine the property ofacid functiona
7、lity. 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 graduations.5.3 Flasks, acid value, 250-mL.6. Reagents and Materials6.1 Purity of ReagentsReagent-grade chemicals orequivalen
8、t, as specified in Practice E200, 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 distilledwater. Dilute with USSD3A denatured ethanol or 95 % ethanolto 1000 mL. Standardize with 0.1 N hydrochloric acid.6.3 Phenol
9、phthalein 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, weighed 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
10、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 color. Theend point is taken when the pink color remains for at least 10s. Swirl the flask vigorously during the titration
11、. 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 solution used.WarningTo avoid saponification, do not reheat the solutionduring this operation.7.3 Run a blank titration
12、 without adding the test sampleunder the same conditions.7.4 Run a total of three titration of sample being tested andone blank.8. Calculation8.1 Calculate the acid number as follows:Acid number 5 A2B! 0.1N! 56.1!/C1This test method is under the jurisdiction ofASTM Committee D21 on Polishesand is th
13、e direct responsibility of Subcommittee D21.02 on Raw Materials.Current edition approved May 1, 2010. Published June 2010. Originallyapproved in 1955 as D1386 55 T. Last previous edition approved in 2004 asD1386 98(2004). DOI: 10.1520/D1386-10.2For referenced ASTM standards, visit the ASTM website,
14、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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.A
15、= millilitres of alkali solution required for titration of thesample,B = millilitres of alkali solution required for titration of theblank sample,N = normality of the alkali solution, andC = grams of sample used.9. Precision and Bias9.1 PrecisionDuplicate results by the same operator shallnot be con
16、sidered suspect unless the results are greater than astandard deviation of 0.8.9.2 BiasThis test has no bias because the values producedare defined only in terms of this test method.10. Keywords10.1 acid number; free acid; natural waxes; polish; syntheticwaxes; titration; waxesASTM International tak
17、es 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 determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own re
18、sponsibility.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 withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addres
19、sed 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 your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at th
20、e 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D1386 102
