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Re: Adhesive for PE




From: 	Geoff Schecht[SMTP:geoffs-at-onr-dot-com]
Sent: 	Monday, September 15, 1997 8:51 PM
To: 	Tesla List
Subject: 	Re: Adhesive for PE



> 
> From: 	Sulaiman Abdullah[SMTP:sulabd-at-hotmail-dot-com]
> Sent: 	Monday, September 15, 1997 12:20 AM
> To: 	tesla-at-pupman-dot-com
> Subject: 	Adhesive for PE
> 
> Hi,
> Can anyone tell me what adhesive to use to glue together 3mm thick 
> pieces & sheets of PE 500 ? (HMW Polyethylene, natural color)
> 
> Thanks in anticipation ... Sulaiman
> 
Hi Sulaiman:

There have been several threads going on about glues for plastics lately so
I guess that I might as well jump on in and give my tuppence-worth from a
practical experience standpoint.

There's nothing that I've ever heard of that can glue polyethylene. To glue
something, you either need to have a solvent action or a bonding action
(ionic, I think but I'm an EE...not a chemist :) ). Solvent welding is what
you do to join plastics like styrene, methacrylate or PVC. Typical solvents
for thermoplastics like these are methyl ethyl ketone, acetone will also
work and I recall reading Malcolm's post about tetrahydrofuran working on
methacrylates like plexiglas. Solvents basically dissolve the plastic to be
joined and when they evaporate, you have a bond....more of a weld,
actually.

Epoxies have a different bonding mechanism. They work well on thermosetting
plastics like phenol-formaldehyde resins (Bakelite), melamine and others
(including cured epoxy resins). Cyanoacrylics ("Krazy Glue") generally work
on these plastics when properly primed but they're not nearly as strong as
epoxies. I've used cyanoacrylic on plexiglas before, also (the glue is
sort-of an unpolymerized version of plexiglas, anyway).

Then there's plastics like teflon, polyproplyene and polyethylene. To my
(limited) knowledge, nothing either dissolves these plastics or sticks to
them well enough to be used to glue them together. Polypropylene and
polyethylene heat bond very nicely, though that's usually only done for
edge seams such as those you find on plastic bags. Conversely, Teflon is
used to line molten glass chutes so it's obviously not going to heat bond
very well (with a heat sealer that you'd likely be able to get for home
use, anyway :(  ).

Sorry for the mini-lecture but I hope this info is useful for future
reference. 

Geoff