Abstract: An aerosol valve for dispensing polyurethane foam including a plastic liner shield to prevent environmental moisture permeating through the sealing grommet into the aerosol can to harden product and disable the valve. The liner has an annular upper portion in the mounting cup channel for sealing to the can bead, an intermediate portion surrounding the grommet in the can, and a lower annular flange extending between the valve stem base and lower grommet surface. A method to assemble the valve components includes inversion of the liner, grommet, valve stem, and mounting cup.

Abstract: A plastic aerosol valve with a plastic valve stem, plastic housing, plastic mounting cup, and plastic locking ring. The plastic valve is assembled into the mounting cup. The plastic housing is assembled into the plastic mounting cup by snap fittings. The plastic mounting cup has a peripheral portion that snap fits up into the plastic locking ring. The plastic locking ring has frangibly-connected upper and lower portions. The lower portion snap fits with the top of a plastic product bottle to mount the aerosol valve assembly on the bottle. The upper ring portion thereafter is telescoped downwardly over the lower ring portion to lock and retain the aerosol valve assembly on the pressurized bottle. The plastic mounting cup can be molded separately, or integrally with the plastic locking ring. A check valve may be contained in the valve stem.