ASTM D7884-20

4.1The presence of 4-CBA and p-TOL in PTA used for the production of polyester is undesirable because they can slow down the polymerization process and 4-CBA imparts coloration to the polymer due to thermal instability.

4.2Determining the amount of 4-CBA and 1.1This test method covers the determination of the 4-Carboxybenzaldehyde (4-CBA) and 1.2In determining the conformance of the test results using this method to applicable specification, results shall be rounded off in accordance with the rounding-off method of Practice E29.

1.3The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4This 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.