1、Designation: D 4660 06Standard Test Methods forPolyurethane Raw Materials: Determination of the IsomerContent of Toluenediisocyanate1This standard is issued under the fixed designation D 4660; 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 These test methods measure the amount of toluene-2,6-diisocyanate (TDI) or toluene2,4diisocyan
3、ate in mixtures ofthe 2,4- and 2,6-isomers. Two test methods are required to giveaccurate results over a broad range of isomer concentrations.1.1.1 Test Method AApplicable to TDI samples contain-ing 5 to 95 % 2,6isomer (95 to 5 % 2,4isomer).1.1.2 Test Method BApplicable to TDI samples contain-ing 0
4、to 5 % 2,6isomer (95 to 100 % 2,4isomer).NOTE 1These test methods are equivalent to ISO 15064.1.2 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 pra
5、ctices and determine the applica-bility of regulatory limitations prior to use. For specificwarning and precautionary statements see Note 3.2. Referenced Documents2.1 ASTM Standards:2D 883 Terminology Relating to PlasticsE 180 Practice for Determining the Precision of ASTMMethods for Analysis and Te
6、sting of Industrial and Spe-cialty Chemicals2.2 ISO Standard:3ISO 15064 PlasticsAromatic Isocyanates for Use in theProduction of PolyurethanesDetermination of the Iso-mer Ratio in Toluenediisocyanate3. Terminology3.1 Terminology in these test methods is in accordance withTerminology D 883.3.2 Defini
7、tions of Terms Specific to This Standard:3.2.1 isomera compound having the same percentagecomposition and molecular weight as another compound butdiffers in chemical or physical properties.3.2.2 isomer contentthe amount of an isomer expressed asa percentage of total isomer amount.4. Summary of Test
8、Methods4.1 Both test methods are based on the quantitative mea-surement of absorption bands arising from out-of-plane C-Hdeformation vibrations of the aromatic ring at 810 and 782cm1(12.3 and 13.8 m).4.2 In Test Method A, the infrared spectrum of a cyclohex-ane solution of the sample is recorded in
9、the 770 to 840-cm1(12 to 13-m) region. The absorbance ratio of the 810 and782-cm1bands is measured and converted to percent toluene-2,6-diisocyanate from a previously established calibrationcurve.4.3 In Test Method B, the absorbance of the 782-cm1bandis measured from an infrared spectrum of an undil
10、uted sampleand then converted to percent 2,6-isomer from a previouslyestablished calibration curve.5. Significance and Use5.1 These test methods can be used for research or forquality control to determine the isomer ratios of toluenediisocyanates.5.2 The isomer ratio of a toluene diisocyanate relate
11、s to itsreactivity.6. Apparatus6.1 SpectrophotometerAny single- or double-beam re-cording infrared spectrophotometer accurate to 0.2 % transmis-sion and capable of resolving the two peaks of the 2,4-isomerdoublet at 810 cm1.1These test methods are under the jurisdiction of ASTM Committee D20 onPlast
12、ics and are the direct responsibility of Subcommittee D20.22 on CellularMaterialsPlastics and Elastomers.Current edition approved Sept. 1, 2006. Published September 2006. Originallyapproved in 1959. Last previous edition approved in 2006 as D 4660 - 00(2006)e1.2For referenced ASTM standards, visit t
13、he ASTM website, 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.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY
14、 10036.1*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.6.2 Cells, sealed sodium chloride (NaCl) liquid absorptioncells with 0.2-mm (Test Method A) and 0.1-mm (Test Met
15、hodB) path lengths. The actual thicknesses of the cells are to beknown to 60.002 mm.6.3 Glassware, 25-mL, glass-stoppered, volumetric flasks,0.80-mL pipet, and an all-glass syringe.7. Reagents and Materials7.1 Purity of ReagentsUse reagent grade chemicals in alltests. Unless otherwise noted, all rea
16、gents conform to thespecifications of the Committee on Analytical Reagents of theAmerican Chemical Society where such specifications areavailable.4Other grades may be used, provided it is ascertainedthat the reagent is of sufficiently high purity to permit its usewithout lessening the accuracy of th
17、e determination.7.2 Cyclohexane, distilled and stored over silica gel toremove traces of moisture.7.3 Diisocyanate StandardsPure samples of 2,4-TDI and2,6-TDI are required for calibration (Note 2). The followingcriteria can be used to judge purity:2,4TDIfreezing point 5 22.0C, n20D5 1.56781, (1)d204
18、5 1.2186, and 2,6TDIfreezing point5 18.2C, n20D5 1.57111, d2045 1.2270.NOTE 2The diisocyanates can be prepared by phosgenating thecorresponding pure amines and vacuum-distilling the products. Sincethese diisocyanates will react with moisture and may discolor in thepresence of air, store them under d
19、ry nitrogen.8. Sampling8.1 Since organic isocyanates react with atmospheric mois-ture, take special precautions in sampling. See 8.1.1. Usualsampling methods (for example, sampling an open drum witha thief), even when carried out rapidly, can cause contamina-tion of the sample with insoluble urea. T
20、herefore, blanket thesample with dry air or nitrogen at all times.8.1.1 WarningOrganic isocyanates are toxic when theyare absorbed through the skin, or when the vapors are breathed.Provide adequate ventilation and wear protective gloves andeyeglasses.9. Test Conditions9.1 Since isocyanates react wit
21、h moisture, keep laboratoryhumidity low, preferably around 50 % relative humidity.TEST METHOD ASAMPLES CONTAINING 5 TO95 % 2,6-TDI10. Calibration10.1 Weigh the amounts of pure 2,4- and 2,6-TDI given in10.1.1 or 10.1.2 into dry, 10-mL, glass-stoppered flasks (Note3). For convenience, a dry pipet may
22、be used. The total weightof each mixture is to be 3.5 to 4.0 g. Carefully shake themixtures. From the weights of pure 2,4- and 2,6-TDI, calculatethe weight ratios (2,4-TDI to 2,6-TDI) of the mixtures,expressed to four significant figures.NOTE 3Dry carefully all glassware since the diisocyanates reac
23、treadily with moisture.10.1.1 Approximate standard mixtures for wide-range cali-bration are given in Table 1.10.1.2 Approximate standard mixtures for short-range cali-brations (see Note 4) are given in Tables 2 and 3 (see Figs. 1and 2).NOTE 4Calibration over a narrow range covering the expected isom
24、erratio gives more accurate results than a wide-range calibration.10.2 Preparation of Standard Solutions Using a pipet,transfer 0.80 mL(0.98 g) of standard mixture into a dry, 25-mLglass-stoppered, volumetric flask. Dilute to volume with cy-clohexane and mix thoroughly.10.3 Fill two 0.2-mm sealed, l
25、iquid absorption cells (one fora single-beam instrument) with cyclohexane and record itsspectrum from 770 to 840 cm1(12 to 13 m). Refill the samplecell with a solution from 10.2 and record the spectrumsuperimposing it over the previously recorded solvent spec-trum. The instrument controls must remai
26、n unchanged betweensamples of a given series. Repeat the process for each solutionfrom 10.2.10.4 Using the solvent spectrum as the baseline, measurethe absorbance of each standard solution sample at 810cm1(2,4-TDI) and 782 cm1(2,6-TDI) and calculate the 810/782-cm1absorbance ratio. Construct a calib
27、ration curve (seeFig. 3) by plotting absorbance ratio (ordinate) versus weightratio of 2,4- to 2,6-TDI (abscissa).10.5 For convenience in short-range calibrations, the absor-bance ratio may be plotted against the concentration, expressedin weight percent, of each isomer (see Figs. 1 and 2). Thisallo
28、ws direct determination of composition without equations,however, the relationship is not linear and the shape of thecalibration curve must be carefully determined.11. Procedure11.1 Using a pipet, transfer 0.8 mL (0.98 g) of sample intoa dry, 25-mL, glass-stoppered, volumetric flask. Dilute tovolume
29、 with cyclohexane and mix thoroughly. Fill the 0.2-mmcell with the solution and record the spectrum from 770 to 8404Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Soc
30、iety, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.TABLE 1 Approximate Standard Mixtures for Wide-RangeCalibrationWeight Ratio%, 2,4-TDI %, 2,6-TDI 2,4-/
31、2,6-TDI5.0 95.0 0.0510.0 90.0 0.1120.0 80.0 0.2530.0 70.0 0.4340.0 60.0 0.6750.0 50.0 1.0060.0 40.0 1.5070.0 30.0 2.3380.0 20.0 4.0090.0 10.0 9.0095.0 5.0 19.00D4660062cm1(12 to 13 m), and without changing instrument settings,refill the sample cell with pure solvent and record its spectrumsuperimpos
32、ed on the sample spectrum.12. Calculation12.1 Using the solvent spectrum as the baseline, measurethe absorbance of the sample at 810 cm1(2,4-TDI) and 782cm1(2,6-TDI) and calculate the 810/782-cm1absorbanceratio. Read from the appropriate standard curve the isomerweight ratio (R), (Fig. 3) or percent
33、age composition (Figs. 1and 2) that corresponds to the measured absorbance ratio.12.2 When using the isomer weight ratio, ( R), calculate thepercentage of each isomer as follows:Percent 2,62TDI 5 100/R 1 1!, and (2)Percent 2,42TDI 5 100 2 percent 2,62TDI (3)Express the result to one decimal place.13
34、. Precision and Bias13.1 PrecisionTable 4 is based on a round robin con-ducted in 1994 involving two samples tested by eight labora-tories. Each laboratory obtained ten test results for eachmaterial on a given day. Short-range calibrations were used.13.1.1 WarningThe following explanations of r and
35、R(13.1.2-13.1.4) are only intended to present a meaningful wayof considering the approximate precision of this test method.The data in Table 1 are not to be rigorously applied to theacceptance or rejection of material, as those data are specific tothe round robin and may not be representative of oth
36、er lots,conditions, materials and laboratories. Users of this test methodare to apply the principles outlined in Practice E 180 togenerate data specific to their laboratory and materials, orbetween specific laboratories. The principles of 13.1.2-13.1.4would then be valid for such data.13.1.2 Repeata
37、bility, r(Comparing two results for thesame material, obtained by the same operator using the sameequipment on the same day). The two results are to be judgednot equivalent if they differ by more than the r value for thatmaterial.13.1.3 Reproducibility, R(Comparing two results for thesame material,
38、obtained by different operators using differentequipment in different laboratories on different days). The tworesults are to be judged not equivalent if they differ by morethan the R value for that material.13.1.4 Any judgment per 13.1.2 and 13.1.3 would have anapproximate 95 % (0.95) probability of
39、 being correct.13.2 BiasThere are no recognized standards by which toestimate the bias of this test method.13.3 It has also been estimated that the results reported bylaboratories are to be considered suspect if they differ from oneanother by more than 60.34 % isomer (short-range calibra-tion).TEST
40、METHOD BSAMPLES CONTAINING0 TO 5 % 2,6-TDI14. Calibration14.1 Prepare the following series of calibration mixturesusing samples of the pure isomers given in Table 5.14.2 Using a 0.1-mm sealed liquid absorption cell, recordthe spectrum of each of the above seven mixtures from 770 to840 cm1.14.3 For e
41、ach of the calibration samples, measure theabsorbance of the 2,6-isomer band at 782 cm1(12.80 m)from a baseline-drawn tangent to the band shoulders. Draw acalibration curve by plotting absorbance versus concentrationof 2,6-isomer.15. Procedure15.1 Fill the 0.1-mm cell with the sample and obtain thes
42、pectrum from 770 to 840 cm1.16. Measurement16.1 Measure the absorbance of the 2,6-isomer band at 782cm1and read the percentage of 2,6-isomer from the calibra-tion curve.17. Precision and Bias17.1 The precision and bias of this test method are underinvestigation by a task group of Subcommittee D20.22
43、. Any-one wishing to participate in this work may contact Chairman,Subcommittee D20.22, through ASTM Headquarters.17.2 It has been estimated that duplicate results by the sameoperator are to be considered suspect if they differ by morethan 60.15 % 2,6-TDI (short-range calibration).17.3 It has also b
44、een estimated that the results reported bylaboratories are to be considered suspect if they differ from oneanother by more than 60.25 % 2,6-TDI (short-range calibra-tion).18. Keywords18.1 FTIR; infrared; IR; isomer; polyurethane raw material;TDI; toluene diisocyanateTABLE 2 Approximate Standard Mixt
45、ures for 80/20 TDI SamplesWeight Ratio%, 2,4-TDI %, 2,6-TDI 2,4-/2,6-TDI75.0 25.0 3.0078.5 21.5 3.6579.0 21.0 3.7679.5 20.5 3.8880.0 20.0 4.0080.5 19.5 4.1381.0 19.0 4.2681.5 18.5 4.4085.0 15.0 5.67TABLE 3 Approximate Standard Mixtures for 65/35 TDI SamplesWeight Ratio%, 2,4-TDI %, 2,6-TDI 2,4-/2,6-
46、TDI60.0 40.0 1.5063.5 36.5 1.7464.0 36.0 1.7764.5 35.5 1.8265.0 35.0 1.8665.5 34.5 1.9066.0 34.0 1.9466.5 33.5 1.9870.0 30.0 2.33D4660063FIG. 1 Calibration Curve Toluene Diisocyanate 80:20FIG. 2 Calibration Curve Toluene Diisocyanate 65:35D4660064FIG. 3 Calibration Curve Toluene Diisocyanate 80:20TA
47、BLE 4 Round Robin Isomer Content of TDI Data Values inUnits of Percent 2,4-TDISample Avrage SrASRBrCRDnETD-80 80.5 0.08 0.16 0.21 0.45 8TD-65 67.3 0.09 0.11 0.26 0.31 4Pooled 0.08 0.14 0.23 0.39 8ASr= within-laboratory standard deviation of the replicates.BSR= between-laboratory standard deviation o
48、f the average.Cr = within-laboratory repeatability limit = 2.8*Sr.DR = between-laboratory reproducibility limit = 2.8*SR.En = number of laboratories contributing valid data for this material.TABLE 5 Approximate Standard Mixtures for 2,4-TDI SamplesWeight of 2,4-isomer,gWeight of 2,6-isomer,g2,6-isom
49、er, %5.000 0.000 0.004.975 0.025 0.504.950 0.050 1.004.900 0.100 2.004.850 0.150 3.004.800 0.200 4.004.750 0.250 5.00D4660065SUMMARY OF CHANGESCommittee D20 has identified the location of selected changes to this standard since the last issue,D 4660 - 00(2006)e1, that may impact the use of this standard. (September 1, 2006)(1) Revised Note 1 to include equivalent ISO standard.Committee D20 has identified the location of selected changes to this standard since the last issue,D 4660 - 00, that may impact the use of this standard
