Afaik you can use the following, in rough order of strength:
1 - chromic acid etch and a suitable glue, 2 - DP-8005, 3 - polyolefin adhesion promotor as used by plastic bumper repair specialists, 4 - sanding and/or flaming (hold the PP in a hot flame for half a second) and a high bond strength polyurethane, preferably flexible 5 - hot melt glue.First, is that correct? And second, did I miss anything?
Thanks,
PP adhesion is pretty darn difficult. Only fluoropolymers and silicone are worse.
Adhesion is always a fun issue to talk around in that everybody understands what adhesion is, but measuring it in any meaningful way is practically impossible. Yes, there are standardized test methods all over the place, but only rarely do the measurements actually correspond to the real failure modes. The tests usually only can provide hints about what is going on. Many of the tests put a great deal of work into the adhered parts, thereby increasing the total amount of worked needed to break a bond part, but betraying our understand of the amount of work needed to break an adhesive.
Some adhesives are great in shear but horrible in peel; some are the other way around. Some of the failures will be cohesive while others will be adhesive. Performance at different temperatures, deformation rates and other environmental conditions also can all play a factor in the strength of an adhesive joint. I won't dirty up the conversation by bringing in such practical considerations such as cost, time, equipment and skill.
As a result, the list you have above is only a general list, although #5 is clearly at the bottom. You did miss heat welding (used for snack bags, for instance) and corona treatment as priming step.
By the way, using "glueing" as a term will make you appear as a rookie. "Adhering" or "joining" are preferred. (Relax, ALL of us were rookies at one point in time!)
John Aspen Research, -
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