1、Designation: D4663 10D4663 15Standard Test Method forPolyurethane Raw Materials: Determination of HydrolyzableChlorine of Isocyanates 1This standard is issued under the fixed designation D4663; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、 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. Scope*1.1 This test method determines the hydrolyzable chlorine content of toluene-2,4-diisocyanate, tol
3、uene-2,6-diisocyanate, ormixtures of the two. It is acceptable to apply this test method to other isocyanates of suitable solubility. (See Note 1.) The mainsources of hydrolyzable chlorine in the isocyanates are carbamoyl chloride and dissolved phosgene. Both of these compounds reactwith alcohols an
4、d water, forming ureas, carbamates, carbon dioxide, and hydrochloric acid. (See Note 2.)1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices
5、 and determine the applicability of regulatorylimitations prior to use.NOTE 1It is possible that this test method is applicable to crude polymeric isocyanates. However, the precision with crude polymeric isocyanates hasnot been established.NOTE 2There is no known ISO equivalent to this standard.This
6、 standard is identical to ISO 15028.2. Referenced Document2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD1193 Specification for Reagent Water2.2 ISO Standards:ISO 15028 PlasticsAromatic Isocyanates for Use in the Production of PolyurethanesDetermination of HydrolysableChlorine33. Terminol
7、ogy3.1 DefinitionsFor definitions of terms used in this test method see Terminology D883.3.2 Definitions of Terms Specific to This Standard:3.2.1 hydrolyzable chloridethe low level chlorine-containing components of the isocyanate, such as carbamoyl chlorides,which react with water or alcohol to form
8、 HCl.4. Summary of Test Method4.1 The hydrolyzable chlorine reacts with methanol, liberating hydrochloric acid. The titratable chlorides are then determinedpotentiometrically using a standard silver nitrate solution.5. Significance and Use5.1 This test method can be used for research or for quality
9、control to characterize toluene diisocyanates. Hydrolyzable chlorinecorrelates with performance in some polyurethane systems.1 This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.22 on Cellular Materials - Plasticsand Elas
10、tomers.Current edition approved July 1, 2010May 1, 2015. Published August 2010June 2015. Originally approved in 1987. Last previous edition approved in 20042010 asD4663 - 98D4663 - 10.(2004). DOI: 10.1520/D4663-10.10.1520/D4663-15.2 For referencedASTM standards, visit theASTM website, www.astm.org,
11、or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.T
12、his document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior edit
13、ions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959
14、. United States16. Interferences6.1 Thiocyanate, cyanide, sulfide, bromide, iodide, or other substances capable of reacting with silver ion,ions, as well assubstances capable of reducing silver ionions in acid solution, will interfere with the determination.7. Apparatus7.1 Weighing Bottle, or any de
15、vice capable of weighing a liquid by difference to the nearest 0.1 g.7.2 Hot Plate, with magnetic stirrer.7.3 Potentiometric Titrator, or pH meter.7.4 Combination Silver Billet Electrode.8. Reagents and Materials8.1 Purity of ReagentsUse reagent grade chemicals in all tests. Unless otherwise indicat
16、ed, it is intended that all reagentsconform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where suchspecifications are available.4 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purityto permit its
17、use without lessening the accuracy of the determination.8.2 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean reagent water as defined byType I of Specification D1193.8.3 Concentrated Nitric Acid (HNO3 sp gr 1.42).8.4 Methanol.8.5 Silver Nitrate Standard Solu
18、tion (0.01 N)Standardize with standard hydrochloric acid, either gravimetrically orpotentiometrically, frequently enough to detect changes of 0.0005 N.9. Sampling9.1 Since organic isocyanates react with atmospheric moisture, take special precautions in sampling. Usual sampling methods,even when carr
19、ied out conducted rapidly, can cause contamination of the sample with insoluble urea. Therefore, blanket the samplewith dry air or nitrogen at all times. (WarningMany diisocyanates are known or suspected sensitizers. Over-exposure todiisocyanates can lead to adverse health effects, which include the
20、 development of occupational asthma and other respiratory, skin,and eye effects. Engineering controls and/orDiisocyanates are eye, skin and respiratory irritants at concentrations above theoccupational exposure limit (TLV or PEL). Diisocyanates can cause skin and respiratory sensitization (asthma) i
21、n some people.Once sensitized, it is essential to limit further exposure to diisocyanates. Use a combination of engineering controls and personalprotective equipment, including respiratory, skin,skin and eye protection, are to be used when there is a potential for to preventover-exposure to diisocya
22、nates. The Consult the product suppliers MaterialSafety Data Safety Sheet (MSDS) provides(SDS) formore detailed information about potential adverse health effects and other importantspecific safety and handling information.Always follow the specific instructions provided on the MSDS.instructions for
23、 the product.)10. Test Conditions10.1 Since isocyanates react with moisture, keep laboratory humidity low, preferably around 50 % relative humidity. SeeSection 9 of this standard for guidance on how to keep moisture out of the sample.11. Procedure11.1 Weigh (by difference to the nearest 0.1 g) 9 to
24、11 g of sample from a sampling weighing bottle into a clean, dry 400-mLbeaker (Note 3). Add 50 mL of methanol and stir. Stir continuallycontinuously while the reaction starts at which point the beakerwill become warm and crystals may form on the sides of the beaker (Note 4). Fill the beaker half-ful
25、l with water (Note 5) and boilgently for 30 min.NOTE 3If the hydrolyzable chlorine content is expected to be less than 0.01 %, use 18 to 22 g of sample.NOTE 4Some isocyanates will not react readily and slight warming may be necessary to initiate reaction. Other isocyanates may react, as indicatedby
26、warming of reactants, but may not form crystals.NOTE 5Add the water quickly to keep the reactants from solidifying and to minimize the loss of HCl.11.2 Wash the sides of the beaker with water and remove and wash the stirring bar. Cool the beaker in an ice bath to about 10Cand add 10 drops of HNO3. T
27、itrate potentiometrically with 0.01 N AgNO3 solution using a silver-silver chloride bination silver billet electrode. If the chloride content is greater than 0.2 %, use 0.1 N instead of 0.01 N AgNO3 solution.4 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Wa
28、shington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.D466
29、3 15212. Calculation12.1 Calculate the hydrolyzable chlorine as weight percent as follows:Hydrolyzable chlorine,%535.453A 3N 3100/10003W !53.5453A 3N/Wwhere:A = AgNO3 solution required for titration of the sample, mL,N = normality of the AgNO3 solution, meq/mL,W = sample used, g, and3.545 = constant
30、 combining the atomic weight of chlorine (35.45 mg/meq), the conversion from milligrams to grams (1000), andconversion to percent (100).13. Precision and BiasNOTE 6Estimate of precision below was determined using a silver-silver chloride electrode which is no longer commercially available.13.1 Preci
31、sionAttempts to develop a precision and bias statement for this test method have not been successful due to thelimited number of laboratories participating in round-robin tests. Data on precision and bias cannot be given for this reason.Anyone wishing to participate in the development of precision a
32、nd bias data should contact the Chairman, Subcommittee D20.22(Section D20.22.01), ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428.13.2 A limited round-robin was conducted.13.2.1 It has been estimated that duplicate results by the same analyst shouldshall be considered suspect if they differ
33、 by morethan 0.001 % hydrolyzable chlorine at the 0.001 to 0.2 % level.13.2.2 It has been estimated that results reported by different laboratories shouldshall be considered suspect if they differ bymore than 0.003 % hydrolyzable chlorine.13.3 BiasThere are no recognized standards by which to estima
34、te the bias of this test method.14. Keywords14.1 aromatic isocyanates; hydrolyzable chlorine; isocyanates; polyurethane raw materials; titration; toluene diisocyanateSUMMARY OF CHANGESCommittee D20 has identified the location of selected changes to this standard since the last issue(D4663 - 98D4663
35、- 10(2004) that may impact the use of this standard. (July (May 1, 20151, 2010)(1) SectionVarious 1: Scope,editorial changes Note 2This change was made to comply with the format specified by D4968Standard Guide for: Annual Review of Test Methods and Specifications for Plastics. throughout the standa
36、rd.(2) Section 7: ApparatusThe electrode was changed to reflect what is currently commercially available.1: ScopeVerified thatISO 15028 is identical to this standard.(3) Section 2: Referenced DocumentsAdded ISO 15028 as a reference.(4) Subsection 9.1: SamplingReference to sampling with a thief was r
37、emoved because this apparatus in no longer commonlyused. The 9.1: SamplingThe previous warning statement was replaced with one developed with input from a ProductStewardship Committee. Our committee is of the opinion that this is a more appropriate statement and is consistent with therequirements of
38、 ASTMs Form and Style Manual.edited to remove non-mandatory language and updated with input from theCenter for the Polyurethanes Industrys (CPI) Product Stewardship Committee.(5) Section 12: CalculationThe significant figures were adjusted in the explanation of terms of the equation. This was done t
39、obe consistent with the number of significant figures used in the equation (the actual equation is unchanged). The equation wasmoved to the front of this section for clarity.10: Test ConditionsRemoved redundant information.(6) Subsection 11.2: ProcedureChanged electrode to the one specified in 7.4.(
40、7) Section 12: CalculationsReplaced picture of equation in 12.1 with text version.(8) SectionSubsection 13: Precision and BiasA note was added indicating that the estimate provided in this section weredetermined using electrodes that are not longer commercially available (see Section 13.2: Precision
41、 and BiasRemovednon-mandatory language.7).D4663 153ASTM International takes 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 righ
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45、e 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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 154
