ASTM D1981-11(2015)

3.1 The color of a tall oil fatty acid is readily affected by heat and oxidization. Variations in degree of heat, time of heat, and exposure to atmosphere during heating have a marked effect on the color obtained; therefore, conformity to the equipment and procedure outlined in this test method is essential to accuracy and precision.

1.1 This test method covers the measurement of the Gardner color of tall oil fatty acids after heating in an atmosphere of nitrogen at 205°C for one or two hours, depending on whether its iodine value is over or under 15, respectively. The specimen may be heated using either an aluminum heating block or an oil bath. This method is applicable to all tall oil fatty acids. Applicability of this method to other types of fatty acids has not been determined.

1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.3 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.