On Oct 17, 2:31 pm, Bill Tuthill wrote:
I have been impressed by the durability of Goretex,
leading to the question, why is Teflon so durable in a garment,
but so non-durable in a frying pan?

What *I* want to know is:

OK, if Teflon plastic, AKA polytetrafluoroethylene, is a "...is a
white solid at room temperature..." (much like many other polmerized
ethylenes!) as is said he

http://en.wikipedia.org/wiki/Polytetrafluoroethylene

then what's that dark brownish coating on cookware made of? Not JUST
Teflon, I'm sure!! The above page says nothing about cookware coating,
or how they take a white plastic and make it into that brownish
coating. I'm curious!

I can totally understand Teflon's low low frictional coefficient, what
with only fluorine atoms on it's molecular outside. Fluorine is THE
most electronegative atom, I believe, resulting in extremely low Van
Der Waal forces which cause friction. So low in fact that Teflon is
the only substance a gecko lizard can't stick to! Someone tell Geico
insurance, quick! ;-)

John Kuthe...

John Kuthe wrote:

What *I* want to know is:
OK, if Teflon plastic, AKA polytetrafluoroethylene, is a "...is a
white solid at room temperature..." (much like many other polmerized
ethylenes!) as is said he

http://en.wikipedia.org/wiki/Polytetrafluoroethylene

then what's that dark brownish coating on cookware made of? Not JUST
Teflon, I'm sure!! The above page says nothing about cookware coating,
or how they take a white plastic and make it into that brownish
coating. I'm curious!

I can totally understand Teflon's low low frictional coefficient, what
with only fluorine atoms on it's molecular outside. Fluorine is THE
most electronegative atom, I believe, resulting in extremely low Van
Der Waal forces which cause friction. So low in fact that Teflon is
the only substance a gecko lizard can't stick to! Someone tell Geico
insurance, quick! ;-)

LOL, great post. "degrades above 260°C (500°F)," hmmm.

Teflon frying pans must have some coloring agent because a white surface
would get dirty quickly. I have a Creuset pot (enamel inside & out)
with blue exterior and off-white interior, now stained halfway up
from cooking black beans.

While we're on frying pans -- I bought a new one at REI this year,
recommended by Backpacker magazine editors. Don't know if the coating
will last any longer than before, but it's a nice utensil. Mainly,
the folding handle shouldn't collapse when you've just got the chicken
cooked and onto the plate -- oops, into the sand.

On Oct 18, 7:39 pm, Bill Tuthill wrote:
John Kuthe wrote:
What *I* want to know is:
OK, if Teflon plastic, AKA polytetrafluoroethylene, is a "...is a
white solid at room temperature..." (much like many other polmerized
ethylenes!) as is said he
http://en.wikipedia.org/wiki/Polytetrafluoroethylene
then what's that dark brownish coating on cookware made of? Not JUST
Teflon, I'm sure!! The above page says nothing about cookware coating,
or how they take a white plastic and make it into that brownish
coating. I'm curious!
I can totally understand Teflon's low low frictional coefficient, what
with only fluorine atoms on it's molecular outside. Fluorine is THE
most electronegative atom, I believe, resulting in extremely low Van
Der Waal forces which cause friction. So low in fact that Teflon is
the only substance a gecko lizard can't stick to! Someone tell Geico
insurance, quick! ;-)

LOL, great post. "degrades above 260°C (500°F)," hmmm.

Teflon frying pans must have some coloring agent because a white surface
would get dirty quickly. I have a Creuset pot (enamel inside & out)
with blue exterior and off-white interior, now stained halfway up
from cooking black beans.

Teflon coating on cookware is probably colored due to the stuff they
have to use to get Teflon to stick to the metal of the pan! I doubt
it's for cosmetic reasons. Think about it: Teflon plastic, AKA
polytetrafluoroethylene, is a white plastic, I'd imagine very close in
appeaance and feel to Nylon or polyethylene. You know, white kinda
soft plastic.

So how do they get this super-low coefficient of drag plastic to be
this thin brownish coating that sticks to cookware but little else
once it's on the cookware? I wanna know!

John Kuthe...

John Kuthe wrote:

Teflon coating on cookware is probably colored due to the stuff they
have to use to get Teflon to stick to the metal of the pan! I doubt
it's for cosmetic reasons. Think about it: Teflon plastic, AKA
polytetrafluoroethylene, is a white plastic, I'd imagine very close in
appeaance and feel to Nylon or polyethylene. You know, white kinda
soft plastic.

So how do they get this super-low coefficient of drag plastic to be
this thin brownish coating that sticks to cookware but little else
once it's on the cookware? I wanna know!

The Wikipedia article on Polytetrafluoroethylene says:
"In 1954, Kansas City buisnessman [sic] Marion A. Trozzolo
created the first pan coated with Teflon non-stick resin."
Linking to:
http://en.wikipedia.org/wiki/Marion_A._Trozzolo

Supposedly eVENT is more breathable than Goretex, but like Goretex,
eVENT is a PTFE based fabric. Sorry for the old 2001 link:
http://verber.com/mark/outdoors/gear/breathability.pdf

John Kuthe wrote:
On Oct 18, 7:39 pm, Bill Tuthill wrote:

John Kuthe wrote:

What *I* want to know is:
OK, if Teflon plastic, AKA polytetrafluoroethylene, is a "...is a
white solid at room temperature..." (much like many other polmerized
ethylenes!) as is said he
http://en.wikipedia.org/wiki/Polytetrafluoroethylene
then what's that dark brownish coating on cookware made of? Not JUST
Teflon, I'm sure!! The above page says nothing about cookware coating,
or how they take a white plastic and make it into that brownish
coating. I'm curious!
I can totally understand Teflon's low low frictional coefficient, what
with only fluorine atoms on it's molecular outside. Fluorine is THE
most electronegative atom, I believe, resulting in extremely low Van
Der Waal forces which cause friction. So low in fact that Teflon is
the only substance a gecko lizard can't stick to! Someone tell Geico
insurance, quick! ;-)

LOL, great post. "degrades above 260°C (500°F)," hmmm.

Teflon frying pans must have some coloring agent because a white surface
would get dirty quickly. I have a Creuset pot (enamel inside & out)
with blue exterior and off-white interior, now stained halfway up
from cooking black beans.


Teflon coating on cookware is probably colored due to the stuff they
have to use to get Teflon to stick to the metal of the pan! I doubt
it's for cosmetic reasons. Think about it: Teflon plastic, AKA
polytetrafluoroethylene, is a white plastic, I'd imagine very close in
appeaance and feel to Nylon or polyethylene. You know, white kinda
soft plastic.

So how do they get this super-low coefficient of drag plastic to be
this thin brownish coating that sticks to cookware but little else
once it's on the cookware? I wanna know!

John Kuthe...

I couldn't help responding to this post.
I lurk in this news group on occasion because it's full of good advice
and I like to canoe.
I use to work with manufacturers of Teflon coated pans ( a while ago -
so the information provided is dated, abridged and subject to the
accuracy of my recollections) - At the time I was involved, Teflon was a
3 coat system.
A base coat which was a polymer mix to adhere to the sand blasted and
etched pan surface, a second coat of PTFE with decorative speckles
(and/or pigments) and a clear over coat of translucent PTFE
The durability of the coating is more a function of the cook ware
manufacturing process than the resin composition.
DuPont got burned on their original Teflon coating by selling the resin
(emulsion) to anybody and allowing them to use the Teflon brand name.
Later coatings like the SilverStone required process approval and
auditing by DuPont in order to use the SilverStone name.
Other companies may use the same coating, but if their process is not up
to par, they can not use the SilverStone trade name.
The white "Teflon" components for lab ware etc. are typically ETFE which
is a thermoplastic as opposed to a thermo set resin (emulsion) system
like PTFE Teflon coatings.

The coating adhesion is mainly mechanical in nature and substrate
preparation is extremely important.
The Teflon has a very low surface tension which prevents it from being
wetted in solid form - However, when melted, it is a low surface tension
liquid and it will wet a substrate very efficiently and creep into every
nook and cranny on the surface.

I hope this information helps to satisfy your curiosity ;-)

Gregg

Gregg wrote:

I hope this information helps to satisfy your curiosity ;-)

Thanks Gregg, that was interesting to read!

--
Wilko van den Bergh wilkoa t)dse(d o tnl
Eindhoven The Netherlands Europe
---Look at the possibilities, don't worry about the limitations.---
http://kayaker.nl/

On Oct 20, 9:43 am, Wilko wrote:
Gregg wrote:

I hope this information helps to satisfy your curiosity ;-)

Thanks Gregg, that was interesting to read!

--
Wilko van den Bergh wilkoa t)dse(d o tnl
Eindhoven The Netherlands Europe
---Look at the possibilities, don't worry about the limitations.---http://kayaker.nl/

Very interesting! One question though. When you said:

A base coat which was a polymer mix to adhere to the sand blasted and
etched pan surface, a second coat of PTFE with decorative speckles
(and/or pigments) and a clear over coat of translucent PTFE

This looks like it means the surface of Teflon cookware coating is
this "clear over coat" rather than the PTFE. So how does the extremely
low friction coefficient of the PTFE come into play if it's covered
with a "clear over coat"? Seems it would be the friction coefficient
of the "clear over coat" that would interface with the food products.
Plus how do they get this "clear over coat" to adhere to the PTFE, if
it's the PTFE that has the extremely low coeff. of friction? I know
it's hard to get paint to adhere to most plastics, of which PTFE is (a
plastic.)

Seems the original fundamental question still remains!

John Kuthe...

John Kuthe wrote:
On Oct 20, 9:43 am, Wilko wrote:

Gregg wrote:


I hope this information helps to satisfy your curiosity ;-)

Thanks Gregg, that was interesting to read!

--
Wilko van den Bergh wilkoa t)dse(d o tnl
Eindhoven The Netherlands Europe
---Look at the possibilities, don't worry about the limitations.---http://kayaker.nl/


Very interesting! One question though. When you said:


A base coat which was a polymer mix to adhere to the sand blasted and

etched pan surface, a second coat of PTFE with decorative speckles
(and/or pigments) and a clear over coat of translucent PTFE

This looks like it means the surface of Teflon cookware coating is
this "clear over coat" rather than the PTFE. So how does the extremely
low friction coefficient of the PTFE come into play if it's covered
with a "clear over coat"? Seems it would be the friction coefficient
of the "clear over coat" that would interface with the food products.
Plus how do they get this "clear over coat" to adhere to the PTFE, if
it's the PTFE that has the extremely low coeff. of friction? I know
it's hard to get paint to adhere to most plastics, of which PTFE is (a
plastic.)

Seems the original fundamental question still remains!

John Kuthe...

Hi John,

Sorry for the confusion
The base coat is a PTFE + second polymer mixture (I can't recall what
the blend is)
The Second coat is PTFE + Pigment
and the top (clear) coat is just PTFE which is translucent.

It's a 3 coating system, but all the layers have PTFE

The PTFE comes in an emulsion form- (small droplets of PTFE suspended in
a carrier fluid). All 3 layers are applied by spraying. The pan is baked
to cure the Teflon only after all three layers have been applied.

The emulsion is formulated so a wetting agent (or detergent like
chemical(s)) wets both the small PTFE particles and the suspension
fluid. This keeps the PTFE in suspension. - like homogenized milk (which
has fat suspended in water)
I imagine that the formulation of these emulsions are no easy task, the
wetting agents must wet PTFE and burn out completely before the Teflon cures

I hope this helps....

Gregg

On Oct 23, 7:11 pm, Gregg wrote:
John Kuthe wrote:
On Oct 20, 9:43 am, Wilko wrote:

Gregg wrote:

I hope this information helps to satisfy your curiosity ;-)

Thanks Gregg, that was interesting to read!

--
Wilko van den Bergh wilkoa t)dse(d o tnl
Eindhoven The Netherlands Europe
---Look at the possibilities, don't worry about the limitations.---http://kayaker.nl/

Very interesting! One question though. When you said:

A base coat which was a polymer mix to adhere to the sand blasted and

etched pan surface, a second coat of PTFE with decorative speckles
(and/or pigments) and a clear over coat of translucent PTFE

This looks like it means the surface of Teflon cookware coating is
this "clear over coat" rather than the PTFE. So how does the extremely
low friction coefficient of the PTFE come into play if it's covered
with a "clear over coat"? Seems it would be the friction coefficient
of the "clear over coat" that would interface with the food products.
Plus how do they get this "clear over coat" to adhere to the PTFE, if
it's the PTFE that has the extremely low coeff. of friction? I know
it's hard to get paint to adhere to most plastics, of which PTFE is (a
plastic.)

Seems the original fundamental question still remains!

John Kuthe...

Hi John,

Sorry for the confusion
The base coat is a PTFE + second polymer mixture (I can't recall what
the blend is)
The Second coat is PTFE + Pigment
and the top (clear) coat is just PTFE which is translucent.

It's a 3 coating system, but all the layers have PTFE

The PTFE comes in an emulsion form- (small droplets of PTFE suspended in
a carrier fluid). All 3 layers are applied by spraying. The pan is baked
to cure the Teflon only after all three layers have been applied.

The emulsion is formulated so a wetting agent (or detergent like
chemical(s)) wets both the small PTFE particles and the suspension
fluid. This keeps the PTFE in suspension. - like homogenized milk (which
has fat suspended in water)
I imagine that the formulation of these emulsions are no easy task, the
wetting agents must wet PTFE and burn out completely before the Teflon cures

Thanks Gregg! I'm sure there's a ton of cool polymer and adhesive
chemistry going on to get the world's slipperiest substance to stick
to cookware and prevent foods from then sticking to the cookware.
Thanks for the explanations.

John Kuthe...