ARTICLE

Edwin B. Faulkner
Director - Comm. & Regulatory Affairs
Sun Chemical Corp
ed.faulkner@na.sunchem.com

Organic Reds for Plastics

Classical Organic Reds - Introduction

Cincinnati -- Henry Ford would have been appalled and aghast if he had to deal with organic reds for coloring plastics. Unlike the Phthalo Green that was discussed in the last issue, there is an abundance of reds available to the master batch formulator. In fact, there are so many that they will be covered in two installments. In this issue, the classical azo reds will be discussed; the high performance ones will be covered in the next edition.

Chemistry, History & Manufacturing Processes  

The vast majority of the azo reds are characterized by the double bonded nitrogen group (-N=N-) joining an aromatic amine to a naphthalene derivative. Depending on the substituant groups on the molecule, some of them are precipitated as metal salts forming insoluble pigments, while others are, by their nature, insoluble. The former are commonly called metalized azo reds. The structures of the metallized azo reds, commonly used in plastics, are shown in Figure 1.

Click to see entire article