Alkaline Papermaking with Anionic Dyes, 1992 Papermakers Conference Proceedings

As the trend toward alkaline papermaking gains momentum in the 90s, we must understand that alkaline wet end chemistry has a major effect on dyed paper. Factors such as types and percentages of fillers, alum, and dual polymer retention systems all have an influence on the dyeing of paper. How these and other factors effect dyeing under alkaline papermaking conditions will be discussed in this article. Based on our experiences, I would like to take this opportunity to discuss with you some of the things that you can expect when you make colored and white grades under alkaline papermaking conditions.

I’d first like to point out that coloring paper under acid or alkaline conditions have one thing in common: it is never easy. Interesting, but not easy. There are many mills currently manufacturing white and colored papers under alkaline conditions. There is a greater number in the process or planning stages to convert from acid to alkaline papermaking. Alkaline papermaking is truly a trend of the 90s!

With the exception of C.I. Direct Yellow 4, which is alkaline sensitive and turns red under alkaline conditions, all anionic direct dyestuffs are successfully being used to produce white and colored grades under alkaline conditions. Most direct dyes have a natural affinity for wood cellulose fibers and exhaust onto them readily. The direct dyes actually Hydrogen bond to the cellulose and do not require size and alum to effect this condition.

Grades being produced under alkaline conditions include text and cover envelope, tablet, offset, carbonless, bond, mimeo, index bristol, ledger, vellum, opaque, and imitation parchments.