LORD HPC-5B / HPC-5C Elastomer Protective Coatings

LORD HPC-5B and HPC-5C are single-component hydrogenated nitrile rubber (HNBR) coatings for elastomer surfaces. They form a protective barrier that improves resistance to fluids and ozone, including resistance to lubricating oils and transmission fluids.

Grade	Appearance and role
HPC-5B	Black coating
HPC-5C	Clear, tintable coating; the liquid has an orange tint

Each grade is a separate coating. HPC-5B and HPC-5C are not components to be mixed together.

The coatings can be applied by spray, brush, dip or roll methods. Cleaning, pretreatment and curing must suit the elastomer. Room-temperature curing is possible for appropriate systems, while some substrates require heat curing to establish adhesion.

Property	HPC-5B	HPC-5C
Viscosity at 25°C, Brookfield LVT, spindle 1, 60 rpm	20–100 mPa·s	20–100 mPa·s
Density	810.03–833.99 kg/m³	805.23–829.20 kg/m³
Solids by weight	8.11%	8.0%

Typical values are for reference, not product specifications.

Stir thoroughly by hand before use. Brush, dip and roll application normally use the coating undiluted. For spray application, suitable ketone solvents include MEK and MIBK with water content no higher than 500 ppm; determine dilution for the spray equipment.

For brush coating, let the first layer dry for about 15 minutes at room temperature, then apply a second layer. Dry the final layer thoroughly before heat curing to reduce blistering from retained solvent.

Surface treatment and cure depend on the elastomer. Natural rubber and nitrile rubber generally require pretreatment. Butyl rubber requires heat curing for adhesion; room-temperature cure should not be treated as suitable for every substrate.

For systems suitable for room-temperature curing, allow at least 24 hours before packaging. Heat curing can improve adhesion and handling strength; 121°C for 10 minutes is an example. Assess adhesion after the final cure and a 24-hour standing period.

The coatings are intended for oil, transmission-fluid and ozone resistance. Extended exposure to aggressive fuels such as Jet A requires separate coating selection; oil resistance does not establish suitability for every fuel.

Shelf life is one year from shipment in the original, unopened container at 21–27°C. Keep the container tightly closed when not in use to limit solvent loss and moisture contamination.

Hongtu Chemical supplies LORD HPC-5B / HPC-5C as an authorized distributor. Contact our team to discuss your materials and process.