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..
paint adhesion to PP
Jan 09, 2005
6 Replies
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
snipped-for-privacy@canoeoutriggers.com 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.
vb
Frank,
I'm sure you meant "increase surface tension".
John
Yes. I guess because I think of decreased contact angle with water. Frank
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
Michael
I am not a bug I am a undocumented feature
Perhaps a chlorinated polyolefin like Trapylen from Tramoco could used.
Oliver
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