Icenene is a possibility. They have 2 products: 1/ the fast cure / expanding foam used on open cavities and 2/ a slow cure / expanding foam for retrofit insulation. The only drawback is price. you should be able to have dense pack cellulose installed for 1/3 to 1/2 of the price with vertually identical preformance. you can also blow fiberglass. It's more expensive than cellulose and doesn't perform as well as icenene or cellulose.