Parylene Conformal Coatings

Suitable for metals, elastomers, electronics and plastics and used extensively in the automotive, aerospace, electronics and medical industries, Parylene Coating is an ultra-thin film polymer coating which provides a consistent pin-hole free barrier coating all shapes, edges, crevices and recesses to the same thickness without suffering any of the edge effects of conventional coatings.

Benefits of Parylene coating

• Ultra-thin film – Coating thickness of less than 1µm can be applied providing sufficient lubricity and barrier protection for most silicone and rubber materials penetrating openings and features as small as 0.01mm
• Pin-hole free barrier – Resistance to chemical attack from organic solvents, inorganic reagents, acids, oxygen and moisture
• Uniform – Thickness tolerances are typically held to ±20% from nominal and tolerances as tight as ±5% are possible even for the most intricate and complex shapes
• Stable – Inert and insoluble in most solvent systems within its temperature range. It is thermally stable between -200°C and 140°C
• Dielectric strength – Extremely high dielectric strength of 5 kV/mil
• Elasticity – Elongation and adhesion of the Parylene film with elasticity above 2x (100%)
• Hydrophobic – Overcomes internal and external fluid build-up in silicone tubes and other components
• Low stress process – Applied at room temperature. Any object which can be exposed to medium vacuum can be coated with Parylene
• Dry Film Lubricant – Eliminates the need for liquid release agents
• Optical clarity – Parylene C is optically clear
• Sterilisation – Coated devices may be sterilised with steam, ETO (Ethylene Oxide Sterilisation) or radiation
• FDA – Parylene is FDA approved

The application process for Parylene coating

Parylene is applied by vapour deposition under a vacuum in a coating chamber at room temperature. The coating process exposes objects to a gas-phase monomer at low pressure. Through vacuum deposition, Parylene condenses and polymerizes on the object’s surface in a polycrystalline formation. The Parylene coating grows at a rate 0.2µm – 0.3µm per minute depending on type N or C respectively.

Parylene C is most widely used as it has good electrical and physical properties.

Parylene N is selected for its high dielectric strength and where greater coating penetration is needed.

Parylene coating is normally applied using a batch process where parts are put into a chamber, either horizontal (tumbler) or vertical. The batch process offers a cost effective solution for many applications.

Applications for Parylene coatings