Ink Rub Resistance

[aqazi81]

How can we increase the ink rub resistance? Can we add wax to the ink, how much and what adverse effects can happen?

 

[Cornishpastythighs]

The degree of rub resistance is a factor of the ink used, the
type of resin contained in the ink and the additives. One
of the most commonly used additives for improving rub
resistance is Teflon wax, which enhances slip performance.
Rub resistance however, is not exclusively related to ink. The
printed material plays an important role too. Glossy papers
have better rub resistance than matt papers. Generally
rough paper is more sensitive to rub than smooth paper.
This is true for ink as well: the smoother the surface, the better
the resistance. Too much ink film thickness could lead to rub issues as could poor ink/water emulsion.Also make sure your press drying system is working properly.

 

[D Ink Man]

Coat your work with either an overprint varnish or aqueous coating.

D Ink Man

 

[Dan Roll]

You can't really add wax to an ink with an ink knife, you would need a dispersion mixer.......

 

[Cornishpastythighs]

I would ask my ink supplier to add any extra to the ink, that way its under a controlled condition and the ink people still own the ink so no finger pointing

 

[D Ink Man]

COAT, as stated.

You can add non-scratch to a finished ink in compound form. No problem, no problem at all.

But we need a tab bit information to really resolve the issue.

COAT, if nothing else.

D Man

 

[aqazi81]

We are facing some issues with reflex blue and violet type colors on Box Boards and Bleach boards, mainly its poor rub resistance which is causing trouble in the post press department, on carton gluer machines we see a lot of scratches and ink coming off the substrate. We know that it can be controlled using AQ coating but our client does not want the job to be coated. That's why I asked you guys that if there is some thing that I can add to the Ink.
We don't have any good ink manufacturer here in our country and we have to import inks from korea through local dealers. No technical support here.

 

[D Ink Man]

Send me your contact info and I will see that you get a product that works.

D

 

[Cold]

Hello Aqazi81,

Given your contsrains I make to you the following suggestions to request for your ink supplier:

1. Pigments - Alkali Blue-PB61 (reflex) and Methyl Violet-PV3 (pantone violet) both impart poor rub characteristics into the ink. Alkali is one of the worst. Sub the alkali blue for a carbazole violet-PV23 and pthalo blue-PB15:3 mixture. Caveat, this is a much weaker color strength of ink. THe methyl violet substitution is easy using carbazole violet.

2. Vehicle System - I recommend a good slug of chinawood(tung nut) varnish and a low VOC resin system. The chinawood varnish will impart a durable hard film while the low VOCs will allow more system to bind the pigment and polymerize.

3. Waxes - double up with a good polyethylene and PTFE(teflon) wax system. 5% and 2% in compound form or 2.5% and 1% in dry.

This type of system may be slower setting than you are used to, however, once cured should show good to great rubresistance on a decent carton stock.

Caveat, if the carton stock has a soft coating, you may have more of an issue than you can fix with ink.

 

[aqazi81]

Thank you guys for giving your input.

 

[Austin12345]

Hi,

I would also like to suggest something that by adding components such as waxes and/or hard-drying oils, an ink’s rub resistance can be improved.Waxes can be Polyethylene or PTFE-based. The amount of wax added can affect the characteristics of the ink. If there is too little wax, little rub resistance will be obtained. If there is too much, it can soften the ink and lead to rub problems. Since lithographic inks need to emulsify with a certain amount of water, excessive wax content in ink can also render it too waterproof.