Retarder in Flexo inks

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jezici
Posts: 3
Joined: Sat May 07, 2011 3:38 pm

Retarder in Flexo inks

Post by jezici »

I was wondering what are you using as a retarder in your solvent based flexo inks? We have wide web flexo machines and for years we been using etoxy propanol as a retarder. In recent times we noticed that we have some lamination issues because of that, so we want to look for another solution.

We were thinking that maybe we would try to use combination of N-propanol and N propil acetat.
PrintBandit
Posts: 8
Joined: Fri Jan 05, 2024 4:56 pm

Re: Retarder in Flexo inks

Post by PrintBandit »

For what it’s worth we stopped allowing “EP” to be freely used due to various issues including lamination due to solvent retention, we also used to print 2-sided liners and the whole reels would block due to the sheer amount being used!

Our go to slower blend is NP & NPA as you suggested, 75/25 mix, but it’s rare we use that for full orders unless we have issues. Our “normal” blend is IMS/NPA (75/25) works for the majority of what we do, neat NP added if needed slowing down.

We still have EP on site but it requires management signature before use, usually based on total coverage of ink being used. Perhaps speak to ink supplier see what options you have to change blends?
guy de cafmeyer
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Re: Retarder in Flexo inks

Post by guy de cafmeyer »

Normal Propyl Acetate is what we use . . .
longtimefan
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Re: Retarder in Flexo inks

Post by longtimefan »

guy de cafmeyer wrote: Fri Feb 09, 2024 1:20 am Normal Propyl Acetate is what we use . . .
Acetate is faster solvent .
Frank Burgos
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Re: Retarder in Flexo inks

Post by Frank Burgos »

Whatever point you get to, whatever amount of this or that to add to your ink, make sure you incorporate it into your formula and standardize it. You don't want a bunch of guys running around adding this or that to the ink based on their knowing this or that. Control it.
Frank Burgos
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Re: Retarder in Flexo inks

Post by Frank Burgos »

This is what I've found, or felt, about acetate vs. propanol.

Ideal blend: 90% propanol, 10% acetate.

It's getting hot out here, and damn, it's humid!: 80% propanol, 20% acetate.

"I don't know what the hell I'm doing!" Do whatever you want.

I have found that NPA makes the ink lay down nicely. However, sometimes you just need a little "cutting power', and crank up the acetate a little.

If you have the 'opportunity' to spend enough time running a solvent-based press, day after day, hour after hour, you get the feel of what is the balance between enough normal-propyl acetate and normal-propyl alcohol. If you use other solvents, I imagine you're printing gravure or another exotic method, a special ink, or in a jungle, and I can't help.
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