Oil seal CRWH1 NBT (C ) 63.5x95.275x11.13 NBR 25091 SKF

NBT coating 

The official proprietary coating for SKF metal housings is called Bore-Tite. It is a water-based acrylic sealant that is factory-applied to the outer metal surface of the seal

Key features of Bore-Tite coating:
Compensates for roughness: The layer is 0.03 to 0.07 mm thick and is elastic, filling small defects and scratches in the housing seat.
Temperature resistance: Withstands operating temperatures up to 200 °C.
Chemical compatibility: Fully resistant to most oils, greases, alcohols, glycols and aqueous solutions of acids and bases.
Limitations: Not compatible with aromatic hydrocarbons, ketones and esters.

Why is it used?
When the seal is fully metal-encased (e.g. CRW1 or CRWHA1 series), there is a risk of microscopic leaks between the metal bed of the machine and the seal itself if the surface is not perfectly ground. The coating eliminates the need to apply additional liquid silicone or adhesive during installation.

Rubber properties - Acrylnitrile-butadiene rubber (NBR):

Standard color: black

NBR rubber demonstrates excellent resistance to the effects of mineral oils. It also provides particularly good results with hydraulic oils, grease, diesel fuels plus other aliphatic hydrocarbons, diluted acids and alkaline solutions that do not contain aromatic or chlorinated additives. Its excellent mechanical properties, such as high resistance to pressure and abrasion, high stability and good temperature resistance (-20°С to +120 °С), ensure a wide application range for this rubber. 

Advantages:

- good oil and fuel resistance (especially to hydraulic oils)

- good working temperature range: -20°С to +120 °С in oil

- good resistance to pressure

- good wear resistance and high tensile strength

- low swelling in water

Limitations:

- poor weather, light and ozone resistance 

- poor resistance to polar fluids 

- poor resistance to chlorinated hydrocarbons 

- poor resistance to aromatic fluids