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How to obtain a PUD [Polyurethane Dispersion?]November 14, 2016
Q. I have trying to stabilize a 2k-PU paint so I can use it for plating jewelry. I have used the following procedure:
- mix the 2k PU paint;
- dilute it by 20%;
- add acetic acid to disperse the PU;
- lastly, add water (about 80%).
However, 1 day after mixing it, the PU does not remain in suspension. It sediments and forms a kind of ball. Please, can anyone give me clue on what to do?
Plating shop employee - São Paulo,Brazil
Hi Walter. Sorry but I'm not familiar with this. Are you suggesting that you believe that you can make a proper solution for CED electrocoating by dispersing reacted polyurethane into a solution of acetic acid and water?
Ted Mooney, P.E. RET
Pine Beach, New Jersey
November 14, 2016
Q. Thank you for your quick response. As I said in my first question. I did the following:
(1) mixed the 2k-PU paint;
(2) diluted the 2k-PU by 20%;
(3) obtained the PU dispersion by adding 3% by volume of acetic acid as recommended in books;
(4) finally adding water (80% by volume) and mix it thoroughly so the dispersed PU can remain in suspension.
However, the PU dispersion did not remain in suspension for a long time. After 1 day, it started forming a kind o ball. I do not what to do to keep it in suspension before coating. Is there a special additive to be used for that purpose?
- São Paulo, Brazil