Are you asking if they are mixed or if you apply one coating of tannic and then a film of vinyl acrýlic? Tannic acid is used in coatings as a primer over already rusted surface to avoid the need to clean the surface.....
When we mixed tanninc acid with vinyle acrylic for preparation of a formulation of coating...so how they works...coz when we mixed .. A lump formation starts...
No, they are used as an independent coatings so you can not mix both....now you know why....I think you're using a vynil.acrylic latex and tannic acid makes the emulsion unstable.
I once formulated both water based and organic based rust converters.
The solvent based was because of; -As the Canadian Army brought armored vehicules from Afghanistan to their Halifax station, they wanted to spray the rust convertor onto their vehicles and park them immediatly on their exterior field without the need to repaint of repair them. (Under the rain & snow).
Understood that the salted sea water already attacked the steel while unboard.
If one apply a water based latex (By the way: Acidic) onto the vehicles to park them out in an field, worst rusting is to be expected.
However, if the formulatin is rather a solvent based one with a certain amount of tannic acid baring a trace of emulsified "Acidic" water; as the film dries out, it become hydrophope.
Then, our civil servants have to go play Golf and plan their time to repair and repaint the armored military vehicles!
To complete my comment, I shall indicate that no binder (Water based latex) intended for rust convertor exist at a alkaline pH. As far as I know, there are only 3 companies that manufacture those latex in North America.
Once one understand that the pigments (Which Tannic acid is, indeed) need to be dispersed into an acidic media, it become easy to imagine that the dispersing aid need to be planed to this specific application!
Otherwise, total collapse of the dispersion is bound to occur!
You wont even be able, have time to disperse your set of pigments and tanic acid, it'll turn into lumps subito-presto!
Many formulations are readily available on the Internet. As long as you gotta the dought $.
Just follow the guide!
Pierre.
thanx Pierre Tanguay for information...can you send the link of any formulation....
Raj
Yes! But I am at home presently! :-)
I mean that the formulations are on my computer in my laboratory where I work.
So, I'll be back on next Monday with the PDF files, uploaded.
However, I cannot give away the solvent based formulation that we once submited to the Canadian Arm Forces. In the end, they may well have figured out that they ought to repair & repaint the armor vehicules right after they are unloaded from the boats...
That solvent based formulation "Sort of" belong to my company...
And, finally use the common water based formulations.
By the way... Some of the resins can be pretty expensive, you know?
There are the "Common" polyvinylidene latex but there is also this ligan complex modified acidic latex to afford an even more "Industrial" grade of a rust converter. I don't recall the technic exactly. Oh! Both are acidics, Huh?
Apart these latexes, I only know of a "Morton" styrene modified acidic latex.
Morten acrylics later got bought by Rohm&Hass, isn't it?
Or was it OmNova? I lost track who buys who? :-) Chemistry is getting weird.
Whoupsy! I got it here!
Hum... How do I upload that file? Ok! Found the button...
And also found the other metal ligan complexed one.
Be carefull. Go to the company website and check if there wouldn't a new one that replaced the 202. There may be an "A" or another letter at the end of the 202 number.
And you got starting formulations in the TDS.
As usual, always order samples and adjust your own formulation.
Last but not least, in the case of ligan complex one, if you have seperation problems (Syneregism). Why wouldn't have a look on BYK-425 for water based systems?
It is quite a bit of an interesting rheology modifier.
Misery! I'm unable to upload any file!
The website proggy keeps on trying to upload but nothing happens.
+ You don't have any email addy...
Oh! Well... Too bad...
Pierre.
Sorry Raj, I let the website here trying to upload one single file all night long and it was still trying to this morning. My connection monitor (Little icon on lower right task bar) as well as my firewall (I see IP#...) tell me that not even one byte went trough!
In short, at least one part of this website isn't working properly.
Maybe no-one ever noticed. I don't know...
Thinking of this, maybe it isn't the right place to ask for formulation in a straight forward way.
I remember asking for a few hints on projects I lead presently (Last ~ 2 years) and never gotten not even a blemish reply.
Maybe the place is for exchanging pure theoretical concepts and not "Applied" technologies which could become legal wrong doing.
I dunno but I let the website try to upload a PDF file of at most (250-500) KB and it didn't move as I woke up this morning.
I'll tell you, why don't go and have a look over Neoresins website?
OmNova's latex (Styrene/Acrylic) is the economic product and not the best one.
That was the reason we used to blend it with the high quality Neoresin's 202.
And for the high performing metal ligand complex modified resins?
Well, even the Canadian Army refused such a price claiming that for that price, handling of the formulation is too laborious. Reason why I had to formulate a solvent based one!
And here, it would be a sure good thing that you known how to handle the "HLB" system in order to permit water (Ionicity) in the given organic media.
Bare in mind that "Strong Organic acids" do exist, phenol among many.
This, until the water finally evaporates after the tannic acid did reacted with rusted metal, coagulating it to form kind of a water repellent gum.
We were asked to participate in the creation of a standard method of testing this new material (Coating) but we simply offer a ~ 20 litre pail so that they could carry whatever tests they might find fit. Since then, never heard back.
We kept one producing our water based formulation based on both Omnova product & Neoresin 202 until sometimes 2 years back. No miracle in there.
I have so many projects, one after the other. Non stop.
One among so many.
I gave what I could give and my best regards are forwarded along this post.
Pierre.
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