1、Designation: D6437 05 (Reapproved 2010)1Standard Test Method forPolyurethane Raw Materials: Alkalinity in Low-AlkalinityPolyols (Determination of CPR Values of Polyols)1This standard is issued under the fixed designation D6437; the number immediately following the designation indicates the year ofor
2、iginal adoption or, in the case of 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.1NOTEReapproved with editorial changes in November 2010.1. Scope1.1 This
3、test method covers measuring alkalinity in low-alkalinity (0.002 meq/g basicity) polyols. This alkalinity isoften expressed as CPR (controlled polymerization rate) ofpolyether polyols. This test method is not applicable toamine-based polyols.1.2 The values stated in SI units are to be regarded as th
4、estandard.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 limitations prior to use.NOTE
5、1There is no known ISO equivalent to this standard.2. Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsE180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals3E691 Practice for Conducting an Interlaborator
6、y Study toDetermine the Precision of a Test Method3. Terminology3.1 Definitions:3.1.1 The terminology in this test method is in accordancewith the standard terminology defined in Terminology D883.3.2 Definitions of Terms Specific to This Standard:3.2.1 CPRcontrolled polymerization rate is expressed
7、asbasicity in milliequivalents per 30 kg of sample (meq/30 kg).4. Summary of Test Method4.1 This test method is a potentiometric titration for samplebasicity in methanol solvent. This test method uses a relativelylarge sample and titration with dilute acid solution to determinetrace quantities of ba
8、sicity.5. Significance and Use5.1 This test method is suitable for quality control, as aspecification test and for research. The urethane reactionbetween polyols and isocyanates to form polyurethane poly-mers is known to be sensitive to the presence of basicsubstances. This is particularly important
9、 in the preparation ofpolyurethane prepolymers which contain isocyanate groupsthat are known to react in the presence of trace amounts ofbasic substances. Since many polyether polyols are often madewith strongly basic catalysts, it is important to have ananalytical method capable of detecting small
10、quantities ofresidual basic substances. This test method is capable ofdetecting ppm levels of base (as KOH).46. Apparatus6.1 Potentiometric Automatic Titrator, capable of detectingmultiple titration end points.6.2 Autotitrator Buret, 5 mL (See Note 2) .6.3 Buret or Dosing Device, capable of dosing 5
11、0 mL.6.4 pH Glass Electrode and Reference Electrode or aCombination Glass Electrode.6.5 Analytical Balance, capable of weighing to the nearest0.01 g.NOTE 2A 1-mL titrator buret can be used if available. Due to the lowvolumes of titrant typically required (0 to 0.5 mL), larger burets will giveless pr
12、ecise results.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 Nov. 1, 2010. Published March 2011. Originallyapproved in 1999. Last previous edi
13、tion approved in 2005 as D6437 - 05. DOI:10.1520/D6437-05R10E01.2For referenced ASTM standards, visit the 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 websi
14、te.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.4H.G. Scholten, J.G. Schuhman, R.E. TenHoor, Journal of Chemical Engineer-ing Data, 5, 1960, p. 396.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, U
15、nited States.7. Reagents and Materials7.1 HCl Aqueous, 0.01 NStandardize to detect changes of0.0001 N.7.2 Methanol, reagent grade8. Procedure8.1 Set up the autotitrator to find multiple end points with amaximum volume of 5 mL.8.2 Place 50 6 0.1 mL of methanol solvent in a 100-mLtitration cup and tit
16、rate a blank using 0.01 N aqueous HCl.8.3 Weigh 30 6 1.00 g of sample into a titration cup. Add50 6 0.1 mL of reagent grade methanol, stir to mix well, andtitrate with 0.01 N aqueous HCl. There will be as many as threeend points (breaks) in these titrations. Use the volume to thelast end point for c
17、alculation.NOTE 3If the viscosity of the sample appears too high, use 100 mL ofmethanol to dissolve the sample.9. Calculation9.1 Calculate the CPR as meq/30 kg of the polyol asfollows:CPR 5 Vsam Vblk! N 30 000/W (1)where:Vsam= volume of titrant to the last break in sampletitration, mLVblk= volume of
18、 titrant to the last break in blanktitration, mLN = normality of HCl,30 000 = conversion factor for 30-kg sample, andW = weight of sample, g.9.2 Calculate alkalinity as micromoles per gram of sampleas follows:mol/g 5 Vsam Vblk! N 1000/W (2)where:1000 = conversion from millimole to mole.9.3 Calculate
19、 alkalinity as micrograms KOH per gram ofsample (ppm KOH) as follows:ppm KOH 5 Vsam Vblk! N 56.1/W (3)where:56.1 = equivalent weight of KOH in mg/meq.10. Precision and Bias510.1 PrecisionTable 1 is based on a round robin con-ducted in 1997 in accordance with Practice E691, involvingfive samples test
20、ed by seven laboratories. Each test result wasthe average of two individual determinations. Each laboratorymade duplicate determinations on each material on each of twodays. (WarningThe following explanations of r and R(10.1.1-10.1.3) are only intended to present a meaningful wayof considering the a
21、pproximate precision of this test method.The data in Table 1 must not be rigorously applied to theacceptance or rejection of material, as those data are specific tothe round robin and will not be representative of other lots,conditions, materials, and laboratories. Users of this testmethod must appl
22、y the principles outlined in Practice E691 togenerate data specific to their laboratory and materials, orbetween specific laboratories. The principles of 10.1.1-10.1.3would then be valid for such data.)10.1.1 Repeatability, r(Comparing two replicates for thesame material, obtained by the same operat
23、or using the sameequipment on the same day.) The two replicate results will bejudged not equivalent if they differ by more than the r value forthat material.10.1.2 Reproducibility, R(Comparing two results, eachthe mean of replicates, for the same material, obtained bydifferent operators using differ
24、ent equipment in different labo-ratories on different days.) The two results will be judged notequivalent if they differ by more than the R value for thatmaterial.10.1.3 Any judgment in accordance with 10.1.1 and 10.1.2would have an approximate 95 % (0.95) probability of beingcorrect.10.2 BiasThere
25、are no recognized standards by which toestimate the bias of this test method.11. Keywords11.1 alkalinity; basicity; CPR; polyether polyol; polyol;polyurethane; prepolymer; raw materials; test method; titra-tion; urethane5Supporting data have been filed at ASTM International Headquarters and maybe ob
26、tained by requesting Research Report RR:D20-1210.TABLE 1 Round-Robin CPR Data in Accordance with PracticeE180Values in CPR UnitsAverage SrASRBrCRDnETerathane 1000 0.34 0.07 0.20 0.20 0.56 7Voranol 4702 0.45 0.06 0.11 0.18 0.32 6Voranol 2120 0.63 0.04 0.12 0.12 0.33 5ARCOL E-656 0.60 0.06 0.16 0.16 0
27、.46 7Multranol 7057 1.24 0.11 0.36 0.30 1.0 6Pooled data . . . 0.07 0.21 0.20 0.59 . . .ASr= within-laboratory standard deviation of the replicates.BSR= between-laboratory standard deviation of the averages.Cr = within-laboratory repeatability limit = 2.8*Sr.DR = between-laboratory reproducibility l
28、imit = 2.8*SR.En = number of laboratories contributing valid data for this material.D6437 05 (2010)12ASTM 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 det
29、ermination 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 years andif not revised, either reapproved o
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31、at 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
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