A guide to building rubber-to-metal and rubber-to-fabric bond strength with pre-dispersed resorcinol-formaldehyde resin and cobalt/nickel activator masterbatches.

The adhesion challenge

Steel cord and fabric reinforcements often peel or show low H-pull values. A resorcinol-formaldehyde resin plus cobalt/nickel activator is the proven route to durable bonding.

How the system works

RF-70 (resorcinol resin) reacts with the rubber phase during cure; RA-65 (cobalt/nickel activator) promotes the metal-to-rubber interface. Pre-dispersion avoids toxic resorcinol dust.

Dosage & process

RF 2-4 phr together with RA 1-2 phr, added at the mixing stage. Cure temperature and time directly affect bond strength.

Applications

Tire belts, steel-cord conveyor belts, hose reinforcement and rubber-to-metal mounts.

TDS / Technical Data Sheet

Products	RF-70 Resorcinol resin / RA-65 Activator
RF active content	70% min.
RA active content	65% min. Cobalt/Nickel complex
Carrier	EPDM / SBR polymer
Appearance	Brown granules
Bond test (H-pull)	reported per batch COA
Shelf life	9 months (resin sensitive to moisture)

SDS Highlights

Contains resorcinol and cobalt complex - classified as harmful if swallowed and a suspect carcinogen. Wear gloves, goggles and respiratory protection; avoid dust. Store tightly sealed and dry.

COA Sample

Batch No.	RA25-0830
RF resin content	70.5%
RA activator content	65.3%
H-pull bond (N)	1180 (typical)
Peel strength	Conforms
Result	PASS

Product Information

Recommended dosage	RF-70 (resorcinol resin) reacts with the rubber phase during cure; RA-65 (cobalt/nickel activator) promotes the metal-to-rubber interface
Packaging	25 kg 纸袋（RF/RA 分别包装），托盘 1000 kg
MOQ	300 kg（约 12 袋）
Shipping port	上海港 / 宁波港
Tags / keywords	resorcinol adhesive system, steel cord rubber adhesion, RF-70 RA-65, tire belt adhesive