HP Indigo Deinkable?

Greetings All,

After some exhaustive study on the matter; my report:

"Executive Summary" on primary topic of De-inking: (though still basically an opinion) To deink HP Indigo output requires a further flotation and dispersing process after initial flotation and screening. Making high quality printing paper solely from Indigo printed paper expensive at this time. I suspect that much of the paper from our plant is either sorted printed/non-printed, with the printed going to cardboard or the mix of printed/non-printed is sufficently clean to pass muster when mixed with other paper waste. In consumer recycling, the indigo printed papers are mixed in with everything else and the percentage is currently low. So, it can be de-inked, but it is expensive. If the amount of Indigo printed paper increases, and/or mills develop a better method for separating the ink from the paper, that could change. However, it can be included with lower grade paper recycleables.
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A few details discovered: The HP document referencing "polymeric film" is a 2008 powerpoint file from a trade show that has had some (out of context?) technical language pasted in poorly, probably by a salesman on a flight to St. Louis. The best technical info I came up with was from the EU patent on the ink:
“Liquid toner comprises toner particles dispersed in a carrier liquid. Printing an image on a substrate using liquid toner involves extracting toner particles from the carrier liquid and depositing the extracted toner particles on the substrate in a pattern suitable to form the image. Once deposited on the substrate the particles are bonded together and to the substrate to provide the finished image.”
I gather that the "bonded together" part might create something like a film, and the MSDS sheet for the ink does include 1% resin, and some trade secret, though it is primarily a petroleum hydrocarbon. Along these lines, I once worked with an issue where hot laminating Indigo printing would sometimes pull the ink right off of the sheet. I've handled the stuff and it is super thin, but it's cohesion was limited to little torn patches, as opposed to a whole sheet of film. (Maybe there's something for the de-inker developers to consider if Indigo printing was separated...use heat and pressure)
-- I'm no chemist, but my inquiry led me to discover that plastics often contain polymers, a polymer is not necessarily a plastic. It has to do with bonded molecules. Plastics are generally moldable. But hey, maybe it is "plasticy". If the recycling tech catches up with the printing tech, which it will eventually, the end result will be good paper...and recyclable polymers! As opposed to toxic offset sludge.
Also of note is a fascinating thread on HP's claim that they use "Ink" not "Toner" from 2008. The de-inking topic comes up as well. Here is the link: Does HP Indigo use “toner” or “ink”? - WhatTheyThink
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anyway, that's more than enough from me! All the best, Mark
 
There are number of printed with water based inks are not deinkable. As the deinkable require special ink receiving layer.
 
So, it can be de-inked, but it is expensive. If the amount of Indigo printed paper increases, and/or mills develop a better method for separating the ink from the paper, that could change. However, it can be included with lower grade paper recycleables.

Hi everybody,

I had not seen that earlier, still a late reply: Even if it would work in an "expensive" process, it would have to be kept separate (by labelling it?) and only directed into that special process; standard mills do have a severe problem and carefully avoid it by checking the incoming waste paper. "Downgrading" for packaging (corrugated) is still possible. Again, for that it must be kept separate from other graphic paper for recycling.

And that Indigo forms a film can be seen if you try to dissolve printed pages in water. The fibers go into the water, leaving large and very thin particles, and these cannot be removed sufficiently in the paper recycling process. The ruler is in centimeters:

Indigo prints in the lab (undeinked) - Indigo prints in the lab (undeinked)Indigo prints in the lab (deinked) - Indigo prints in the lab (deinked)

The press release is old, but nothing has changed since.

By the way, such problems also occur from UV-cured inks, basically a similar issue: large and crosslinked ink particles that cannot be remove during the deinking process (see press release).

What is relevant in Europe: No ecolabels for Indigo or UV prints.
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If you need more information, you're welcome to contact me via the INGEDE website!
 
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