paint adhesion to PP

I'm in the automotive paint repair business. The problem is getting paint to stick to raw PP. Can someone explain to me why paint doesn't stick to PP? I know that PP has a waxy surface throughout. All feedback appreciated. Thanks..

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Not familiar with specifics of PP but normally you have to adhesion activate polyolefins. Commercially flaming and electrostatics can do. They slightly oxidize surface to carboxyls to lower surface tension and provide chemical bonding sites. Frank

Reply to
Frank Logullo schrieb:

1st: Low surface energy of PP makes wetting hard for most liquids. 2nd: Nonpolar structure of PP reduces physical interactions with any material that gets in contact with the PP surface.

Surface energy and physical interactions can be increased by introducing polar groups by e.g. flaming or plasma treatment.


Reply to
Volker Borst


I'm sure you meant "increase surface tension".


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Yes. I guess because I think of decreased contact angle with water. Frank

Reply to
Frank Logullo

Normaly your paint is some pigment in an polar polymer (PU) solved

your PP is totaly unpolar

so you have no wetting of your PP by your colour without wetting there is no chancve for adhesion

in oder to get wetting you can flame the PP (some seconds in a buthane o propane flame you can use corona or plasam

all of these possibilities are not usefull for your business...

so you have to find a suitable primer for your problem and ofer the people a repairtkit with two steps.

I think Rohm and Haas should have a primer system for that problem


I am not a bug I am a undocumented feature

Reply to
Michael Erwerle

Perhaps a chlorinated polyolefin like Trapylen from Tramoco could used.


Reply to
Oliver 'Ojo' Bedford

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