1、Designation: D4663 10Standard Test Method forPolyurethane Raw Materials: Determination of HydrolyzableChlorine of Isocyanates1This standard is issued under the fixed designation D4663; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision
2、, 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 chlorinecontent of toluene-2,4-diisocyanate, toluene-2,6-d
3、iisocyanate,or mixtures of the two. It is acceptable to apply this test methodto other isocyanates of suitable solubility. (See Note 1.) Themain sources of hydrolyzable chlorine in the isocyanates arecarbamoyl chloride and dissolved phosgene. Both of thesecompounds react with alcohols and water, for
4、ming ureas,carbamates, carbon dioxide, and hydrochloric acid. (See Note2.)1.2 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
5、 the applica-bility of regulatory limitations prior to use.NOTE 1It is possible that this test method is applicable crudepolymeric isocyanates. However, the precision with crude polymericisocyanates has not been established.NOTE 2There is no known ISO equivalent to this standard.2. Referenced Docume
6、nt2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD1193 Specification for Reagent Water3. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod see Terminology D883.3.2 Description of Term Specific to This Standard.3.2.1 hydrolyzable chloridethe low level chlorine-conta
7、ining components of the isocyanate, such as carbamoylchlorides, which react with water or alcohol to form HCl.4. Summary of Test Method4.1 The hydrolyzable chlorine reacts with methanol, liber-ating hydrochloric acid. The titratable chlorides are thendetermined potentiometrically using a standard si
8、lver nitratesolution.5. Significance and Use5.1 This test method can be used for research or for qualitycontrol to characterize toluene diisocyanates. Hydrolyzablechlorine correlates with performance in some polyurethanesystems.6. Interferences6.1 Thiocyanate, cyanide, sulfide, bromide, iodide, or o
9、thersubstances capable of reacting with silver ion, as well assubstances capable of reducing silver ion in acid solution, willinterfere with the determination.7. Apparatus7.1 Weighing Bottle, or any device capable of weighing aliquid by difference to the nearest 0.1 g.7.2 Hot Plate, with magnetic st
10、irrer.7.3 Potentiometric Titrator, or pH meter.7.4 Combination Silver Billet Electrode.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.22 on Cellular Materials -Plastics and Elastomers.Current edition approved July 1,
11、2010. Published August 2010. Originallyapproved in 1987. Last previous edition approved in 2004 as D4663 - 98(2004).DOI: 10.1520/D4663-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume
12、information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.8. Reagents and Materials8.1 Purity of Rea
13、gentsUse reagent grade chemicals in alltests. Unless otherwise indicated, it is intended that all reagentsconform to the specifications of the Committee on AnalyticalReagents of the American Chemical Society where suchspecifications are available.3Other grades may be used, pro-vided it is first asce
14、rtained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.8.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as definedby Type I of Specification D1193.8.3 Concentrated Nitric A
15、cid (HNO3sp gr 1.42).8.4 Methanol.8.5 Silver Nitrate Standard Solution (0.01 N)Standardizewith standard hydrochloric acid, either gravimetrically orpotentiometrically, frequently enough to detect changes of0.0005 N.9. Sampling9.1 Since organic isocyanates react with atmospheric mois-ture, take speci
16、al precautions in sampling. Usual samplingmethods, even when carried out rapidly, can cause contamina-tion of the sample with insoluble urea. Therefore, blanket thesample with dry air or nitrogen at all times. (WarningManydiisocyanates are known or suspected sensitizers. Over-exposure to diisocyanat
17、es can lead to adverse health effects,which include the development of occupational asthma andother respiratory, skin, and eye effects. Engineering controlsand/or personal protective equipment, including respiratory,skin, and eye protection, are to be used when there is apotential for over-exposure
18、to diisocyanates. The productsuppliers Material Data Safety Sheet (MSDS) provides moredetailed information about potential adverse health effects andother important safety and handling information. Alwaysfollow the specific instructions provided on the MSDS.)10. Test Conditions10.1 Since isocyanates
19、 react with moisture, keep laboratoryhumidity low, preferably around 50 % relative humidity.11. Procedure11.1 Weigh (by difference to the nearest 0.1 g) 9 to 11 g ofsample from a sampling weighing bottle into a clean, dry400-mL beaker (Note 3). Add 50 mL of methanol and stir. Stircontinually while t
20、he reaction starts at which point the beakerwill become warm and crystals may form on the sides of thebeaker (Note 4). Fill the beaker half-full with water (Note 5)and boil gently for 30 min.NOTE 3If the hydrolyzable chlorine content is expected to be lessthan 0.01 %, use 18 to 22 g of sample.NOTE 4
21、Some isocyanates will not react readily and slight warmingmay be necessary to initiate reaction. Other isocyanates may react, asindicated by warming of reactants, but may not form crystals.NOTE 5Add the water quickly to keep the reactants from solidifyingand to minimize the loss of HCl.11.2 Wash the
22、 sides of the beaker with water and removeand wash the stirring bar. Cool the beaker in an ice bath toabout 10C and add 10 drops of HNO3. Titrate potentiometri-cally with 0.01 N AgNO3solution using a silver-silver chlorideelectrode pair. If the chloride content is greater than 0.2 %, use0.1 N instea
23、d of 0.01 N AgNO3solution.12. Calculation12.1 Calculate the hydrolyzable chlorine as weight percentas follows:Hydrolyzable chlorine, % 5 35. 45 3 A 3 N 3 100/1000 3 W !5 3.545 3 A 3 N / Wwhere:A = AgNO3solution required for titration of thesample, mL,N = normality of the AgNO3solution, meq/mL,W = sa
24、mple used, g, and3.545 = constant combining the atomic weight of chlorine(35.45 mg/meq), the conversion from milligrams tograms (1000), and conversion to percent (100).13. Precision and BiasNOTE 6Estimate of precision below was determined using a silver-silver chloride electrode which is no longer c
25、ommercially available.13.1 PrecisionAttempts to develop a precision and biasstatement for this test method have not been successful due tothe limited number of laboratories participating in round-robintests. Data on precision and bias cannot be given for thisreason. Anyone wishing to participate in
26、the development ofprecision and bias data should contact the Chairman, Subcom-mittee D20.22 (Section D20.22.01), ASTM, 100 Barr HarborDrive, West Conshohocken, PA 19428.13.2 A limited round-robin was conducted.13.2.1 It has been estimated that duplicate results by thesame analyst should be considere
27、d suspect if they differ bymore than 0.001 % hydrolyzable chlorine at the 0.001 to 0.2 %level.13.2.2 It has been estimated that results reported by differentlaboratories should be considered suspect if they differ by morethan 0.003 % hydrolyzable chlorine.13.3 BiasThere are no recognized standards b
28、y which toestimate the bias of this test method.14. Keywords14.1 aromatic isocyanates; hydrolyzable chlorine; isocyan-ates; polyurethane raw materials; titration; toluene diisocyanate3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestio
29、ns on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.D4663 102SUMMARY OF CHANGESCommit
30、tee D20 has identified the location of selected changes to this standard since the last issue(D4663 - 98(2004) that may impact the use of this standard. (July 1, 2010)(1) Section 1: Scope, Note 2This change was made tocomply with the format specified by D4968 Standard Guidefor: Annual Review of Test
31、 Methods and Specifications forPlastics.(2) Section 7: ApparatusThe electrode was changed toreflect what is currently commercially available.(3) Subsection 9.1: SamplingReference to sampling with athief was removed because this apparatus in no longercommonly used. The previous warning statement was
32、replacedwith one developed with input from a Product StewardshipCommittee. Our committee is of the opinion that this is a moreappropriate statement and is consistent with the requirementsof ASTMs Form and Style Manual.(4) Section 12: CalculationThe significant figures wereadjusted in the explanation
33、 of terms of the equation. This wasdone to be consistent with the number of significant figuresused in the equation (the actual equation is unchanged). Theequation was moved to the front of this section for clarity.(5) Section 13: Precision and BiasA note was added indi-cating that the estimate prov
34、ided in this section were deter-mined using electrodes that are not longer commerciallyavailable (see Section 7).ASTM 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 advi
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37、 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. Individ
38、ual 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/).D4663 103
