DAS (4,4'-Diamino-2,2'-stilbenedisulfonic acid) Technical Grade from China
Technical grade DAS is a high-purity form of 4,4'-diamino-2,2'-stilbenedisulfonic acid used in optical brightener production. It falls under HTS 2921.59.2000 due to its precise chemical identity as a chemically defined aromatic polyamine per Chapter 29 note (a). Impurities are minimal and do not alter its classification.
Duty Rate — China → United States
41.5%
Rate breakdown
9903.03.0110%Except for products described in headings 9903.03.02–9903.03.11, articles the product of any country, as provided for in subdivision (aa) of U.S. note 2 to this subchapter
9903.88.0325%Except as provided in headings 9903.88.13, 9903.88.18, 9903.88.33, 9903.88.34, 9903.88.35, 9903.88.36, 9903.88.37, 9903.88.38, 9903.88.40, 9903.88.41, 9903.88.43, 9903.88.45, 9903.88.46, 9903.88.48, 9903.88.56, 9903.88.64, 9903.88.66, 9903.88.67, 9903.88.68, or 9903.88.69, articles the product of China, as provided for in U.S. note 20(e) to this subchapter and as provided for in the subheadings enumerated in U.S. note 20(f)
Import Tips
• Request supplier specs showing >95% purity to distinguish from 'other' polyamines in 2921.59.8000
• Declare exact CAS number (128-71-2) on entry documents for customs verification
• Check for stabilizer additions; per Chapter notes, these don't change classification if for safety/transport