1、Designation: D 6437 05Standard Test Method forPolyurethane Raw Materials: Alkalinity in Low-AlkalinityPolyols (Determination of CPR Values of Polyols)1This standard is issued under the fixed designation D 6437; the number immediately following the designation indicates the year oforiginal adoption o
2、r, in the case of 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 This test method covers measuring alkalinity in low-alkalinity (0.002 meq/g
3、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 thestandard.1.3 This standard does not purport to address all of thesafet
4、y 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 1There is no similar or equivalent ISO standard.2. Referenced Documents
5、2.1 ASTM Standards:2D 883 Terminology Relating to PlasticsE 180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial ChemicalsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 Definitions:3.1.1 T
6、he terminology in this test method is in accordancewith the standard terminology defined in Terminology D 883.3.2 Definitions of Terms Specific to This Standard:3.2.1 CPRcontrolled polymerization rate is expressed asbasicity in milliequivalents per 30 kg of sample (meq/30 kg).4. Summary of Test Meth
7、od4.1 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 basicity.5. Significance and Use5.1 This test method is suitable for quality control, as
8、 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 in the preparation ofpolyurethane prepolymers which contain isocyanate groupsthat are
9、 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 quantities ofresidual basic substances. This test method is capable ofdetecting ppm le
10、vels of base (as KOH).36. 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 50 mL.6.4 pH Glass Electrode and Reference Electrode or aCombination Glass Electrode.6.
11、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 precise results.7. Reagents and Materials7.1 HCl Aqueous, 0.01 NStandardize to detect ch
12、anges 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 titrate a blank using 0.01 N aqueous HCl.1This test method is under the jurisdiction of
13、ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.22 on Cellular Materials -Plastics and Elastomers.Current edition approved March 1, 2005. Published March 2005. Originallyapproved in 1999. Last previous edition approved in 1999 as D 6437 - 99.2For referenced ASTM st
14、andards, 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 website.3H.G. Scholten, J.G. Schuhman, R.E. TenHoor, Journal of Chemical Engineer-ing Data,
15、5, 1960, p. 396.1*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.8.3 Weigh 30 6 1.00 g of sample into a titration cup. Add50 6 0.1 mL of reagent grade methanol, stir to
16、 mix well, andtitrate with 0.01 N aqueous HCl. There can be as many as threeend points (breaks) in these titrations. Use the volume to thelast end point for calculation.NOTE 3If the viscosity of the sample appears too high, use 100 mL ofmethanol to dissolve the sample.9. Calculation9.1 Calculate the
17、 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 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
18、.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 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
19、 mg/meq.10. Precision and Bias410.1 PrecisionTable 1 is based on a round robin con-ducted in 1997 in accordance with Practice E 691, involvingfive samples tested by seven laboratories. Each test result wasthe average of two individual determinations. Each laboratorymade duplicate determinations on e
20、ach 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 approximate precision of this test method.The data in Table 1 must not be rigorously applied to theacceptance or rejection of material, as tho
21、se data are specific tothe round robin and will not be representative of other lots,conditions, materials, and laboratories. Users of this testmethod must apply the principles outlined in Practice E 691 togenerate data specific to their laboratory and materials, orbetween specific laboratories. The
22、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 operator using the sameequipment on the same day.) The two replicate results will bejudged not equivalent if they differ by more than the r value
23、forthat material.10.1.2 Reproducibility, R(Comparing two results, eachthe mean of replicates, for the same material, obtained bydifferent operators using different equipment in different labo-ratories on different days.) The two results will be judged notequivalent if they differ by more than the R
24、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 are no recognized standards by which toestimate the bias of this test method.11. Keywords11.1 alkalinity; basicity; CPR; polyether polyol; p
25、olyol;polyurethane; prepolymer; raw materials; test method; titra-tion; urethane4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D201210.TABLE 1 Round-Robin CPR Data in Accordance with PracticeE 180Values in CPR UnitsAverage SrA
26、SRBrCRDnETerathane 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 0.46 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 re
27、plicates.BSR= between-laboratory standard deviation of the averages.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.D6437052SUMMARY OF CHANGESCommittee D20 has identified
28、the location of selected changes to this standard since the last issue,D 6437 - 99, that may impact the use of this standard. (March 1, 2005)(1) Added units to improve clarity in 9.1.(2) Removed non-mandatory language from 8.3, 10.1.1,10.1.2, Note 2, and the Warning note in 10.1.ASTM International t
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31、essed 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
32、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 (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).D6437053
