NyeBar-Q environmentally-friendly barrier film
NyeBar-Q environmentally-friendly barrier film
Keywords Environmentally friendly, Film
Fast evaporating dispersions that leave a tenacious film on metal, glass or fabric to repel water, oil and dirt have been used for many years to protect a variety of products ranging from precision aerospace mechanisms to furniture and take-away pizza boxes.
Recent new worldwide protocols question the environmental acceptability of many traditional constituent materials. This is causing immense problems in many industries.
Nye Lubricants Inc. have invested considerable effort over many years in the progressive improvement of their NyeBar Barrier Film products and now announce their totally new NyeBar-Q range which is currently believed to be the only such barrier film product on the global market that fully complies with all current international environmental legal requirements (see Plate 5).
Plate 5NyeBar-Q is a non-flammable solution whose solvent rapidly vaporizes on application to almost any surface
NyeBar-Q is a non-flammable solution whose solvent rapidly vaporizes on application to almost any surface. It deposits a hard, totally dry, invisible molecular barrier film, which is characterized by very low surface energy. Liquids of almost any kind falling on such a surface are unable to wet it and simply roll away, like rain off a polished car or water off a duck's back!
Theory of wettability and oil creep prevention
Liquids will spread on or "wet" any surface where surface energy is higher than the surface tension of the fluid. Because of the very high surface energies of metals, fluids would be expected to spread or creep on any truly clean metal surface. By modifying in advance the surface of a metal or other solid with a stable, durable film of low surface energy, it is possible to retard the migration or creep of fluids on that surface. Wettability of surfaces can be controlled and protection can be obtained from very thin film coatings.
NyeBar-Type Q
NyeBar-Type Q is a stable fluorocarbon polymer with a surface energy well below the surface tension (at room temperature) of most lubricating fluids,including the easily-migrating silicones. The NyeBar polymer is supplied in solution in fast-evaporating completely fluorinated carrier solvents. At room temperature, the film remaining after evaporation of the solvent will prevent"wetting" of the surface and creep of oils across the film surface. Spreading can, however, occur from gravitational or inertial forces, as:
when fluid quantity is sufficiently large that it literally "falls"across the barrier film; or
when rotational speeds are sufficiently high that they sling the fluid over the film.
NyeBar-Q films can endure temperatures to 200°C and can control creep of even low surface tension methyl silicone oils at that temperature. The principal vulnerability of the applied film would be its resistance to abrasion. Handling of treated parts should be minimized.
Application of NyeBar
NyeBar-Type Q can be applied to any clean metal, plastic or glass surface by dipping the component in the solution, by spraying the solution on the part, or,for small areas of a device, by brushing the area to be protected. Air drying for five minutes permits evaporation of the carrier solvent, and a very thin but fully effective film will remain. Some customers have found that baking the applied film for 15 minutes at 100°C produces a more durable and abrasion resistant film.
Prevention of lubricant migration
When using NyeBar-Type Q to prevent migration of lubricating oils, the NyeBar solution should not be applied in the area requiring lubrication but rather as a dam or barrier around that area. For a pivot bearing, a "doughnut"around the pivot is a useful solution. Where it is desired to prevent oil from spreading along a rotating shaft, a simple ring around the shaft should suffice. For ball bearings, inner and outer race faces should be coated with barrier film. Shields, shims, shield retainers and retaining rings should be coated also. Extreme care should be taken that no barrier film be permitted to contact bearing race lands, separators, balls or ball grooves.
Contamination of these latter components with the barrier film would render them non-wettable by the lubricant, resulting in possible lack of lubrication and subsequent bearing failure.
The NyeBar films are readily dissolved by fluorinated solvents and to a lesser extent by chlorinated solvents. Nyebar-Type Q is relatively resistant to other commonly-used solvents, however, prolonged immersion of the film should be avoided. An immersion of NyeBar treated bearings or components in any effective solvents can dissolve the film and redeposit it in a bearing raceway or other vulnerable area and bearing failure can result. Mark all treated components"BC" ("barrier-coated") to alert bearing users to the hazards of solvent immersion.
Protection of electrical contacts and printed circuit boards
An ultra-thin coating of NyeBar-Type Q can serve to protect electric contacts from contamination caused by creep of silicone or other oils from nearby apparatus. NyeBar has been proven in such use in telephone relay systems. Current flow and signal integrity are not affected by the presence of the thin NyeBar film.
NyeBar films can also be used to protect printed circuit boards from atmospheric and environmental contaminants. They can repel moisture, oil and attendant dust entrapment and yet be sufficiently thin to permit current flow. Such films can serve as alternatives to the traditional thicker conformal coatings which require masking of contact points during application.
Product characteristics: NyeBar-Type Q
Appearance – clear and colorless liquid.
Solvent – fluoroalkane.
Concentration of resin in solvent (available limits) – 0.1-2.0 per cent.
Flash point of solution – non-flammable.
Boiling point of solvent – below 60°C.
Specific gravity of solution, 25°C – 1.7.
Temperature capability of film – up to 200°C.
Surface energy of film – approximately 11 dynes/cm.
Solvents and dilution
Theoretically a monomolecular layer of the NyeBar-Type Q film should be effective in most protective or oil retarding applications. Experience has shown that the standard 2 per cent solution can be diluted certainly to 0.2 per cent,and in some cases to as low as 0.1 per cent, with successful results and substantial economic saving.
Storage and handling
Storage
NyeBar solutions should be stored at or near room temperature. If frozen, or if solids separate, bring to room temperature and stir to assure solution. Do not use if precipitate does not re-dissolve. When not in use, the container should be kept tightly closed.
Handling
This product contains a volatile fluoroalkane solvent. In high concentrations, its vapor reduces oxygen available for breathing. Do not use without adequate ventilation or vapor exhaust. Keep container closed and avoid vapor inhalation. Avoid extended or repeated skin contact. Avoid vapor or liquid contact with intense heat sources, since pyrolysis products can be highly toxic. Consult the Material Safety Data Sheet on NyeBar-Type Q for more detailed safety information.
For more information contact Don Haydon on +44 208296 0650 or visit www.electromotif@blueyonder.co.uk
