[Prev][Next][Index][Thread]
Re: Bonding Polypropylene &pe
On Tue, 02 Nov 1999 19:30:49 -0700, Tesla List wrote:
> Original Poster: "ROBERT CRESSLER" <59CREROB-at-menasha-dot-com>
>
> hello all,
> I forgot the original thread ..... but in regards to
> adhesives for low surface energy materials.. check out
> HTTP://www.nbond-dot-com/faq.html
> I 'stumbled' across and have not used myself,but it sure looks like the
> cat's meow
> Robert
>
Spoke with Bill, the co spokesman today and ordered a 50 ml sampling kit for
$35.00
Asked some questions;
I told him I already had hot air welder, and asked whether this would be a
satisfactory preheat treatment to secure good bonding. Also indicated I also
had corona discharge device used as leak detector.
His reply was that a propane torch treatment is the most sensible approach,
its not the heat but amount of oxygen that can react on the surface area
that makes the good bonding. Somewhat mystified I later asked him on a
return call why I couldnt just run oxygen from a tank through the hot air
welder to pretreat the seam corners that have leak problems. His reply was
that it is the free radicals of Oxygen (OH?) that do this job and
recommended the use of his dyno sensing pen to see if material to be applied
will bond good.
Made some comments about his web page that the acrobat dingbat doesnt work
without downloading ect.The leak detector is a corona discharge device that
essentially appears to be a portable tesla coil device producing small 3/4
inch arcing used to detect leaks in seams. I obtained this in coordination
with plastic welder purchase, after my welds did not seal at corners, hence
my interest in poly bond 33 material. I was quite dismayed at the leak
detector in action, it seemed to go through 3/8 HDPE quite easily at high
setting.
My thinking on this became, maybe this is what is talked by energizing the
material prior to bonding, again wrong answer; Bill says it is only the
presence of the ozone that does this, and in the final analysis several
quick sweeps of a propane torch does a better job because that creates the
free oxygen radicals.
Kind of confused why the exotic methods mentioned are supposed to be better,
yet not practical.
Flourine gas? I cant imagine what customer would want to go to that expense.
I am only going to try the product and hopes it works in my application.
Incidently Bill does say that it will bond polypropylene to polyethylene,
quite an unusual claim, but the material seems expensive enough for that
kind of specialty application.
I worked in the plastic processing industry for 17 years where we always
hated polypropylene mixing. It gives off a bad fume that quickly fills the
air. Never welded with it though, and from the problems described by the
welding operation, dont want to either.
One of the things that industry likes to sell is called concentrates.
Another material is mixed with the holder material. For example many times
we mixed powdered ferrite, cabosil bonded onto diffrent grades of poly. The
buyers of material also seem elusive towards what they use the finished
product for, that is part of their trade secret, they just give a recipe,
and the company tries to mix it in a banbury mixer, and to also pelletise it
so that it can be formed in plastic molding or extrusion machinery as a
finished product.
I always thought that common ordinary parafin wax could become the
experimentors choice of a dielectric material fashioned to choice by
addition of materials.
For example titanium dioxide has a high dielectric constant, it is in a
powdered form, and the plastic industry does not need to be paid to put it
into a solid form. It can be added into molten wax, which incidentally is
another poly molecule with quite similar qualities. This mixture can be
poured into test tubes and when it solidifies one will see that the TiO2
has all settled to the bottom of the tubes, containing the maximum
concentration the wax will hold. A small amount of heat enables those forms
to be melted out of their containers while still solid. Then the white
portions are sawed from the transparent, and voila, we now have a titanium
wax concentrate with a superior dielectric constant that can then be melted
back into actual forms in the needed capacitor. I experimented also with
ferrite(also magnetic) and cabosil wax mixtures as well. Cabosil is a form
of synthetic anyhydrous silica that can give a glasslike texture. I actually
made a cement mixture employing this and ferrite that seemed to have a
dielectric constant of 32! however it became crumbly after time.
I also remember the repressive police state that confiscated my cabosil
supply under the guise that it was in my car, and it resembled cocaine.
Those officers should have snorted some of it for good measure, and you can
be sure I insisted the Ohio crime lab had to return my material.
Anyways bad to go off topic.
Sincerly HDN tesla4-at-excite-dot-com
________________________________________________________________
Get FREE voicemail, fax and email at http://voicemail.excite-dot-com
Talk online at http://voicechat.excite-dot-com