Part B Resins

Part B is the isocyanate component of the cold box phenolic urethane system. It is mixed in the sand with Part A (phenolic resin) and, when gassed with amine, reacts with the resin to form urethane bonds and set the core rapidly.

Because isocyanate reacts with moisture, Part B should be kept in a closed container, and humidity in the sand and the environment should be controlled. Moisture reduces core strength and shelf life.

Part A and Part B must be used together at the recommended ratio. Isocyanates can cause respiratory and skin sensitisation, so ventilation and personal protective equipment are required. The safety data sheet should be followed.