Printech Archive
Hazardous Waste Generated in Litho Printing


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From: Deb Jacobson (djacobson@istc.illinois.edu)
Date: Mon Nov 15 1999 - 06:52:10 CST


>This Ask PNEAC question is from:
>
>---------------------------------------------
>Printech:
>
>I'm doing a project about hazardous waste generated by lithography printing.
One of my recommendation is to use soy-based ink instead of oil-based ink.
However, from articles that I read, it seems that the solvent used to clean
blankets are still the same type of solvent (which has high VOC content). I
was
wondering if I changed the type of ink, it is possible to change the type of
cleaning solvent (to a lesser VOC content).

Unless the lithographic ink (soy or petro based) contains high levels of heavy
metals regulated by EPA under RCRA the waste is typically not considered
hazardous. Each state's hazardous waste regulations are different, but
generally lithographic ink waste itself is considered "special" waste. The
fact that it contains or does not contain soy oil has no impact.

As far as using alternative solvents, again the type of ink has no impact. A
litho printer using soy or petroleum based inks can use alternative, lower VOC
blanket washes. The key thing for performance reasons is that products
containing a high VOC, but a low vapor pressure (less than 10 mm Hg) will
perform much better and still emit less VOC due to the lower evaporation rate.

It may help you to read up on lithographic inks. Essentially all soy based
inks still contain a significant amount of petroleum products as well. There
is no such thing as 100% soy ink due to the fluidity of the soy oil.

I'm also interested in the cost for using this type of soy-based ink and the
suggested solvent (if there's any). Could you also advice me with other
suggestion on how to minimize the waste generated?

When soy based inks were first introduced they were slightly higher priced.
Now that the market has matured they are about the same price as traditional
petroleum based inks. Alternative, lower VOC emitting cleaning products do
cost more (as much as 2-3 times more) however a cost savings can be realized
because the printer is using considerably less cleaning product.

For other waste minimization ideas see the PNEAC fact sheets on shop towels
and
the John Roberts Co. case study on eliminating type wash solvent. Please
understand that compared to other printing methods (flexo, gravure, screen)
lithographic printing does not generate a lot of Hazardous Waste as a rule.
For instance, the waste ink is primarily non-hazardous special waste as
long as
hazardous wastes are not mixed in.

>Thank you.
>

I hope this helps clarify your questions and thank you for visiting the PNEAC
web site.

Regards,

Debra Jacobson
----------------------------------------------------------------------------
---------------------------------
Debra Jacobson (formerly Kramer)
E-mail Address djacobson@istc.illinois.edu (Revised 9/99)
IL Waste Management & Research Center / IL Dept of Natural Resources
(PNEAC/GPP http://www.pneac.org)
1010 Jorie Boulevard, Suite 12
Oakbrook, IL 60523
630/472-5019
630/472-5023 Fax
---------------------------------


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