Chemistry of Foam
The chemistry of foam or chemically what is happening here. Using the example of the Pur Fill 1G, it is polyurethane resin under pressure.
The can should be room temperature or above when you are foaming. If your foaming on a cold day, put the can in the cab of your truck to get it up to room temperature.
What happens at room temperature is when you pull the trigger the propellent boils blowing up the polyurethane resin and you get 12 gallon of cured foam out of the can.