ASTM D4890-98(2003)
(Test Method)Standard Test Methods for Polyurethane Raw Materials: Determination of Gardner and APHA Color of Polyols
Standard Test Methods for Polyurethane Raw Materials: Determination of Gardner and APHA Color of Polyols
SCOPE
1.1 These test methods measure visually the color of clear polyester and polyether liquids. They apply only to materials whose colors have light-absorption characteristics similar to those of the standards. An alternative method is Test Method D 1209. (See Note 1.)
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Note 1
Although Test Method A of these test methods and ISO 4630-1997 differ in some details, data obtained using either are technically equivalent. Although Test Method B of these test methods and ISO 6271-1981 differ in some details, data obtained using either are technically equivalent.
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Designation:D 4890–98 (Reapproved 2003)
Standard Test Methods for
Polyurethane Raw Materials: Determination of Gardner and
APHA Color of Polyols
This standard is issued under the fixed designation D 4890; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope ISO 4630-1997 Binders for Paints and Varnishes—
Estimation of Color of Clear Liquids by the Color Scale
1.1 These test methods measure visually the color of clear
ISO 6271-1981 Clear Liquids—Estimation of Color by the
polyester and polyether liquids. They apply only to materials
Platinum-Cobalt Scale
whose colors have light-absorption characteristics similar to
those of the standards. An alternative method is Test Method
3. Terminology
D 1209. (See Note 1.)
3.1 For definitions of terms used in these test methods see
1.2 This standard does not purport to address all of the
Terminology D 883.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4. Summary of Test Method
priate safety and health practices and determine the applica-
4.1 In Test Method A, the color of the material to be tested
bility of regulatory limitations prior to use.
is compared to a series of color standards with defined
NOTE 1—AlthoughTest MethodAof these test methods and ISO 4630-
chromicity coordinates, prepared on one of three ways. The
1997 differ in some details, data obtained using either are technically
results are reported as the color standard, which best matches
equivalent.Although Test Method B of these test methods and ISO 6271-
the sample.
1981 differ in some details, data obtained using either are technically
4.2 In Test Method B, the color of the material to be tested
equivalent.
is compared to a series of platinum-cobalt color standards,
2. Referenced Documents
designatedbymgofPt/mLofstandardsolution.Theresultsare
reported as the color standard, which best matches the sample
2.1 ASTM Standards:
(Note 2).
D 883 Terminology Relating to Plastics
D 1193 Specification for Reagent Water
NOTE 2—Color of liquids also can be measured by visible spectroscopy
D 1209 Test Method for Color of Clear Liquids (Platinum-
and the results converted to any of several color scales. These results can
Cobalt Scale) be converted to the APHA scale by appropriate manipulations, as for
example in Test Method D 5386.
D 5386 Test Method for Color of Liquids UsingTristimulus
Colorimetry
5. Significance and Use
E 308 Practice for Computing the Colors of Objects by
5.1 These test methods are suitable for quality control, as
Using the CIE System
specification tests, and for research. Color is an important
E 1164 Practice for Obtaining Spectrophotometric Data for
property of urethane products.
Object-Color Evaluation
2.2 ISO Standards:
6. Sampling
6.1 Polyesters and polyethers usually contain molecules
ThesetestmethodsareunderthejurisdictionofCommitteeD20onPlasticsand covering an appreciable range of molecular weights. These
are the direct responsibility of Subcommittee D20.22 on Cellular Materials—
have a tendency to fractionate during solidification. Unless the
Plastics and Elastomers.
material is a liquid or finely ground solid it is necessary to melt
Current edition approved November 1, 2003. Published December 2003.
(using no higher temperature than necessary) and mix the resin
Originally approved in 1988. Last previous edition approved in 1998 as D 4890 -
98.
well before removing a sample for analysis. Many polyols are
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
hygroscopic and care should be taken to provide minimum
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
exposure to atmospheric moisture during the sampling.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 4890–98 (2003)
TABLE 1 Gardner Reference Standard Color Solutions
Chromaticity
Iron-Cobalt Solutions
A Potassium
Coordinates
Gardner Color Standard Potassium Dichromate,
Chloroplatinate, g/1000
B
Number g/100 mL Sulfuric Acid
Ferric Chloride Cobalt Chloride
mL of 0.1 NHCl
xy Hydrochloric Acid, mL
Solution, mL Solution, mL
1 0.3190 0.3271 0.550 . . . . . . . . . 0.0039
2 0.3241 0.3344 0.865 . . . . . . . . . 0.0048
3 0.3315 0.3456 1.330 . . . . . . . . . 0.0071
4 0.3433 0.3632 2.080 . . . . . . . . . 0.0112
5 0.3578 0.3820 3.035 . . . . . . . . . 0.0205
6 0.3750 0.4047 4.225 . . . . . . . . . 0.0322
7 0.4022 0.4360 6.400 . . . . . . . . . 0.0384
8 0.4179 0.4535 7.900 . . . . . . . . . 0.0515
9 0.4338 0.4648 . . . 3.8 3.0 93.2 0.0780
10 0.4490 0.4775 . . . 5.1 3.6 91.3 0.164
11 0.4836 0.4805 . . . 7.5 5.3 87.2 0.250
12 0.5084 0.4639 . . . 10.8 7.6 81.6 0.380
13 0.5395 0.4451 . . . 16.6 10.0 73.4 0.572
14 0.5654 0.4295 . . . 22.2 13.3 64.5 0.763
15 0.5870 0.4112 . . . 29.4 17.6 53.0 1.041
16 0.6060 0.3933 . . . 37.8 22.8 39.4 1.280
17 0.6275 0.3725 . . . 51.3 25.6 23.1 2.220
18 0.6475 0.3525 . . . 100.0 0.0 0.0 3.00
A
Chromaticity coordinates for CIE standard illuminant C and the CIE 1931 (2°) standard observer.
B
Thedichromatecolorstandardshavebeenfoundtobelessreliablethanchloroplatinateoriron-cobaltcolorstandards.TheyareincludedinTable1forreferenceonly.
7. Purity of Reagents 9.2 FerricChlorideSolution—Prepareasolutioncontaining
approximately 5 parts by weight of ferric chloride
7.1 Purity of Reagents—Reagent-grade chemicals shall be
(FeCl 3 6H O) and 1.2 parts of HCl (1 to 17).Adjust to exact
3 2
used in all tests. Unless otherwise indicated, it is intended that
color equivalence to a freshly prepared solution containing 3 g
all reagents shall conform to the specifications of the Commit-
of K Cr O in 100 mL of H SO (sp gr 1.84).
2 2 7 2 4
tee onAnalytical Reagents of theAmerican Chemical Society,
4 9.3 Hydrochloric Acid (1 to 17)—Mix 1 volume of concen-
where such specifications are available. Other grades may be
trated hydrochloric acid (HCl, sp gr 1.19) with 17 volumes of
used, provided it is first ascertained that the reagent is of
water.
sufficiently high purity to permit its use without lessening the
9.4 Hydrochloric Acid (0.1 N)—Prepare 0.1 N HCl.
accuracy of the determination.
9.5 Potassium Chloroplatinate (K Cr O ).
2 2 7
7.2 Purity of Water—Unless otherwise indicated, references
9.6 Potassium Dichromate (K Cr O ).
2 2 7
to water shall be understood to mean reagent water as defined
9.7 Sulfuric Acid (sp gr 1.84)—Concentrated sulfuric acid
by Type IV or better of Specification D 1193.
(H SO ).
2 4
TEST METHOD A—GARDNER COLOR
10. Gardner Color Reference Standards
8. Apparatus 10.1 The primary standards for color shall consist of solu-
tions defined by their spectral transmittance in 1-cm cell with
8.1 Gardner-Holdt Tubes, of clear glass, with closed, flat,
parallel sides. The chromaticity coordinates of these solutions
even bottoms, and having the following approximate dimen-
shall conform to those given in Table 1 when determined on a
sions and markings:
1-cm layer of the solution in accordance with Practice E 1164
8.1.1 A uniform internal length of 112 mm,
and Test Method E 308.
8.1.2 A uniform internal diameter throughout the length of
10.2 For comparison, permanent solutions of known color
the tube of 10.75 mm, and
are more satisfactory. The approximate composition of solu-
8.1.3 An etched line around the outside of the tube 5 mm
tions giving each of the 18 Gardner colors is also given in
from the open end and a second etched line around the outside
Table 1. The solutions shall be made from K PtCl in 0.1 N
2 6
of the tube 13 mm from the open end.
HCl, or, in the darker colors, from stock solutions of FeCl ,
9. Reagents CoCl , and HCl (9.1, 9.2, and 9.3).
10.3 Sol
...
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