Significance and Use
CIELAB is a visual-based scale that can be used to specify color and set color tolerances for the polyurethane industry.
Yellowness Index specifies the degree of departure of the sample from colorless towards yellow. This index is only suitable for clear liquids with degrees of saturation in yellow (dominant transmission wavelength in the 570 to 580 nm range). It can be used to set tolerances for appropriate polyurethane raw materials.
This test method does not include provisions for materials with fluorescence or visible haze (usually greater than 5 % haze).
Before proceeding with this test method, make reference to the specification of the material being tested. Any test specimen preparation, conditioning, dimensions, or testing parameters or combination thereof, covered in the materials specification shall take precedence over those mentioned in this test method. If there are no material specifications, then the default conditions apply.
1. Scope
1.1 This test method provides an instrumental method for measuring the CIELAB color and Yellowness Index (YI) of liquid polyurethane raw materials. The CIELAB and YI results are derived from mathematical manipulation of CIE tristimulus values in accordance with Practices E308 and E313, respectively.
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—There is no known ISO equivalent to this standard.
2. Referenced Documents (purchase separately) 
The documents listed below are referenced within the subject standard but are not provided as part of the standard.
ASTM Standards
D883 Terminology Relating to Plastics
D1193 Specification for Reagent Water
E180 Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial and Specialty Chemicals
E284 Terminology of Appearance
E308 Practice for Computing the Colors of Objects by Using the CIE System
E313 Practice for Calculating Yellowness and Whiteness Indices from Instrumentally Measured Color Coordinates
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
Keywords
CIELAB; color; colormetric analysis; instrumental measurement; isocyanates; L*a*b*; light; methylene di(phenylisocyanate); polyols; polyurethane raw materials; polyurethanes; spectrophotometry; transmission; tristimulus; yellowness index; YI; Yellowness index; Color; Instrumental measurement--color/light; Polyurethane raw materials;
ICS Code
ICS Number Code 83.080.20 (Thermoplastic materials)
DOI: 10.1520/D7133-11
ASTM International is a member of CrossRef.
Citing ASTM Standards
[Back to Top]
