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WHY
PARYLENE?
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.
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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.
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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.
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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.
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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.
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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.
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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
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High gas
barrier properties (H20, 02, etc.).
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Exceptional
rust prevention.
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Strong
resistances to solvents, acids and alkalis.
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Excellent
electrical propel1ies of Insulation and Dielectricity.
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Excellent
mechanical properties at super low temperature.
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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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