ASK JOE POWDER
The “Ask an Expert” Column Kevin Biller
kbiller@chemquest.com
Even for this last column of the year, there are still many questions for our expert Joe Powder from coaters around the world.
Hi Joe,
The powder coating industry has developed chemistries and processes
I have a technical question to ask. I hope you have the answer.
that allow MDF to be coated commercially. Please let me know if you
I read some non-technical articles mentioning powder coating
would like to know more about these chemistries.
on wood. How is it can be done because wood is a non-magnetic
Best regards,
material?
Joe
Have a good day! Dr. Jinwen Zhang
Dear Joe,
Washington State University
I hope that you and your family are well. Long time no see. How is your business?
Hello Dr. Zhang,
I have a question, regarding Qualicoat Class 1 approval. For
Electrostatics and not magnetism is used to deposit dry powder onto a
polyester-TGIC powder coating the gloss should not be less than
substrate. Nevertheless, this is still a good question.
50% after 1000 hours Xenon Arc exposure. I want to know if a
Most wood has surface characteristics that allow electrostatic
powder based on a standard polyester-TGIC resin will pass this
deposition of powder onto its surface. In some cases, like MDF (medium
test (approximately equivalent to 1 year Florida). Or do we need
density fibreboard), the “wood” needs to be preheated to allow
another type of polyester resin for Class 1 or no?
moisture to migrate to the surface of the board. This moisture provides
My pleasure will be hearing from you.
enough conductivity to deposit the charged powder.
Regards,
One of the challenges to coat wood is having a powder coating
Mohammed Seddighian
chemistry that cures at low temperatures. If the cure temperature is
Tehran, Iran
too high the wood emits volatiles that ruin the coating appearance.
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N. 78 - NOVEMBER/DECEMBER 2022 - international PAINT&COATING magazine