Abstract: A device is disclosed which achieves a constant rate of release of an active ingredient in the temperature range of 5.degree. to 45.degree. C., which comprises a container having at least a portion of its surface membrane consisting essentially of polyethylene, polypropylene, or copolymers thereof, said membrane having a thickness of less than 6 mil, and within the container a solution of active ingredient in a solvent in contact with a negative release modulator, wherein the negative release modulator is less miscible with the solution at 5.degree. C. than at 45.degree. C.

Abstract: The invention is concerned with a method and device for the time release of a fragrance such as a perfume, the odor of the fragrance released being substantially unchanged from the odor of the original fragrance. The fragrance is sealed or otherwise enclosed within a container at least one portion of which comprises a permeable membrane of polyethylene or polypropylene, the membrane having a thickness of no more than about 6 mils (0.01524 cm), the fragrance including a top note, a middle note, an end note and alcohol (such as ethanol) having a molecular weight below 100. Fragrance components slowly pass through the membrane so as to provide an odor adjacent the membrane which is unchanged from the odor of the fragrance within the container.