Parylene is
considered by many
to be the ultimate
conformal coating
for the protection
of devices,
components and
surfaces in the
electronics,
instrumentation,
aerospace, medical
and engineering
industries.
-
Parylene is
unique in being
created directly
on the surface
at room
temperature.
-
There is no
liquid phase
involved.
Coatings are
truly conformal,
of uniform
controllable
thickness, and
are completely
pinhole-free at
thicknesses
greater than
0.5μ.
-
The coating
completely
penetrates
spaces as narrow
0.01mm.
-
No initiators or
catalysts are
involved in the
polymerisation
so the coating
is very pure and
free from trace
ionic
impurities.
-
Room temperature
formation means
the coatings are
effectively
stress-free.
-
Any substrate
that is
vacuum-stable
can be coated
and the coating
adheres strongly
to all
materials, even
stainless steel,
provided the
appropriate
adhesion-promotion
techniques are
used.
-
Parylene is
chemically and
biologically
inert and stable
and make
excellent
barrier
materials.
-
Parylene is
almost
completely
unaffected by
solvents, have
low bulk
permeability and
are hydrophobic.
Coatings easily
pass a 100hr
salt-spray test.
-
Parylene has
excellent
electrical
properties: low
dielectric
constant and
loss with good
high-frequency
properties; good
dielectric
strength; and
high bulk and
surface
resistivities.
-
Parylene has
good thermal
endurance:
Parylene C
performs in air
without
significant loss
of physical
properties for
10 years at 80°C
and in the
absence of
oxygen to
temperatures in
excess of 200°C.
-
Parylene is
transparent and
can be used to
coat optical
elements.
-
Coatings perform
well as dry
lubricants:
static and
dynamic friction
coefficients are
equal and
comparable to
fluoropolymers
with the
advantage that
they also have
good wear and
abrasion
resistance.
-
FDA approval of
parylene-coated
devices is
well-documented.
The coatings
comply with USP
Class VI
Plastics
requirements and
are MIL-I-46058C
/ IPC-cc-830B
listed (as class
XY).
-
A
Poly-para-Xylylene
coating film
formed by the
chemical vapor
deposition (CVD)
process.
The coating film
is completely
pinhole free and
the film
thickness can be
uniformly
controlled in
the micron range
to conform to
any irregular
shape, whether
it has a sharp
edge or a
complicated
internal surface
without any
thermal stress.
-
Parylene
is a
conformal
protective
polymer
coating
material
utilized
to uniformly
protect any
component
configuration
on such
diverse
substrates
as metal,
glass,
paper,
resin,
plastic,
ceramic,
ferrite and
silicon.
Because of
its unique
properties,
Parylene
conforms to
virtually
any shape,
including
sharp edges,
crevices,
points; or
flat and
exposed
internal
surfaces.
-
Parylene
provides
exceptional
protection
for the most
extreme
environmental
conditions.
This polymer
is called
out as "Type
XY" coating
in the MIL
specs such
as
MIL-I-46058C,
and
IPC-CC-830.
Parylene is
unique as it
is deposited
through a
vacuum
deposition
system, as
gaseous
molecules
capable of
providing a
pin-hole
free film at
3 microns
thickness.
This method
of
application
yields a
true
conformal
film
complexion
that
contours all
surfaces,
exposed or
hidden.
Further, the
thickness of
the Parylene
film could
be very
tightly
controlled
due to this
unique
method of
deposition.
-
The Parylene
film is
chemically
inert, no
acid or
alkaline
material
will attack
it in any
significant
manner.
The FDA has
approved the
Parylene
film for
human
implantable
devices. The
Parylene
film
possesses
superior
dielectric
properties,
approaching
8000 volts
for 1 mil
thickness.
-
Usages for
the Parylene
coating
includes,
implantable
devices,
fish tags,
circuit
boards (SMT,
Thru-hole,
or mixed
technology)
sonar
applications,
ultrasonic
applications,
surgical
devices, and
elastomers.
The Parylene
coating
process
involves
changing the
molecular
structure of
the Parylene
dimer into a
monomer,
then
depositing
monomers at
room
temperature
onto the
substrate to
form the
polymeric
chain of the
Parylene
film.
-
Parylene
coatings are
completely
conformal,
of uniform
thickness
and pinhole
free.
This is
achieved by
a unique
vapor
deposition
polymerization
process. The
advantage of
this process
is that the
coating
forms from a
gaseous
monomer
without an
intermediate
liquid
stage.
As a result,
component
configurations
with sharp
edges,
points, flat
surfaces,
crevices or
exposed
internal
surfaces are
coated
uniformly
without
voids.
-
Parylene has
no curing
cycle,
unlike other
conformal
coating
materials.
Once
deposited,
it is ready
to go to
work.
-
Parylene has
chemical
resistance
similar to
Teflon. It resists
attack and is
insoluble in all
organic solvents
up to iS00C and
is resistant to
permeation by
most solvents
with the
exception of
aromatic
hydrocarbons.
Since Parylene
coating is a
high molecular
weight, linear,
crystalline
polymer having
an all carbon
backbone without
any oxygen,
nitrogen, or
sulfur atom
links in the
backbone it is
hydrophobic.
This carbon
backbone,
coupled with its
substantial
crystallinity,
makes Parylene
quite stable and
highly resistant
to chemical
attack.
TYPICAL FEATURES
OF THE PARYLENE
FILM
-
High gas
barrier
properties
(H20,
02,
etc.).
-
Exceptional
rust
prevention.
-
Strong
resistances
to
solvents,
acids
and
alkalis.
-
Excellent
electrical
propel1ies
of
Insulation
and
Dielectricity.
-
Excellent
mechanical
properties
at super
low
temperature.
-
Low
out-gassing.
PARYLENE GENERAL
PROPERTIES/BENEFITS
-
MIL-I-46058C,
Type XY
approved
-
FDA approved
-- USP XXII,
Class VI
bio-compatibility
rating
-
UL listed
-
Completely
pin-hole
free barrier
coating
-
Fully
conformal on
any type of
surface
material or
design
-
Inert
transparent
polymer
-
Meets NBC
requirements
(AR70 /
AFR80-38 /
Navinst
3400.2)
-
Barrier to
oxygen,
moisture,
chemicals,
solvents,
and carbon
dioxide
-
Thermal
mechanically
stable
between
-200ºC and
150ºC
-
Extremely
high
dielectric
5,000 volts
per 0.001"
minimum
-
Excellent
adhesion
properties
-
Low stress
coating that
does not
form sites
prone to
crack
initiation
-
Low /
minimal
impact on
package
cooling
-
Hydrophobic
-
Barrier to
ionic and
moisture
species
-
Chemical and
fungal
resistance
-
Non-contaminating
coating and
coating
process --
no solvents,
catalysts or
other
by-products
are
introduced
during
coating
-
Entire
process is
accomplished
at room
temperature,
alleviating
temperature
stress on
parts
-
Particle
encapsulation
/
immobilization
-
No
outgassing
(NASA
approved)
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