Resin
From Roofing, Solar Power, and Spray Foam Insulation Wiki
Resin
(1) The "B" component in SPF that is mixed with the "A" component in order to form polyurethane. Resin contains a catalyst, fire retardants, a blowing agent, Polyol, and a surface active agent.
(2) Component B in urethane foam chemistry. This component is mixed with the A component to form foam insulation.