Re: flexo-de-inking

Wayne Pferdehirt (
pferdehi@epd.engr.wisc.edu)
Tue, 25 Jun 1996 08:30:14 CST


------- Forwarded Message Follows -------
From: John Serafano

Kathy:

There have been numerous published reports on problems of flexo
deinking. This problem is more evident in flexo news printing
operations, particularly, water base flexographic inks. In
conventional newspaper printing drying is accomplished by absorption
of the ink oils into the paper structure. The inks oils in offset
news inks never totally dry.

In newspaper flexo the water base inks dry and form a hard film layer
of acrylic polymer and pigment. Flotation deinking is not adequate to
remove the cellulose fiber bond and dry ink film. However, flexo news
has been successfully recycled using combination washing and
flotation. A typical problem with flexo news deinking is the
secondary pulp yield is reduced and the brightness may be lower.

The problem with deinking water base ink on uncoated paper has drawn
attention to publication printers in general. We continue to work
toward the use of water base ink in gravure publication printing.
Deinking of these products at this scale will pose more of a
challenge.

**********************************************************
Wayne P. Pferdehirt, P.E., AICP


 

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