Patent CA-1200530-A (CA)
Inventor: VAN LOVEREN AUGUSTINUS G
IPC: A61L9/04
Filed: 1983-06-07
Granted: 1986-02-11
Abstract: ABSTRACT OF THE DISCLOSURE      Described is a process for dispensing at a constant rate, continuously or discontinuously for discrete periods of time, a volatile composition of matter from a container into the atmosphere surrounding said container which volatile composition of matter can be in the alternative, a perfume composition, a deodorant composition an air freshener composition, an insecticide composition, a herbicide composition, an odor masking composition, a pheromone composition, composition for the evaluation of olfactory functioning in humans, an animal repellent composition, or an insect repellent composition as well as a container for use in conjunction with said method which container is a hollow totally enclosed flexible, rigid or partially flexible-partially rigid structure comprising a thin shell totally enclosing an inner void, said thin shell having a base portion and an upper portion, said base portion having an inner surface:     (i)  contained totally within said inner void of said thin shell and in place on said inner surface of said base portion, a volatile composition entrapped at least at the instant in time, 00 (t = 0) of commence-ment of the functional operation of said structure, in an entrapment material;     (ii)  at least a finite section of said thin shell comprising a porous polymer (which may or may not contain a plurality of finite solid particles, e.g. "filler") said porous polymer having a porosity such that when said hollow totally enclosed structure is located in the ambient environment said volatile material molecules are either (a) adsorbed onto the inner surface of the microporous polymer section and desorbed fromthe microporous polymer from the outer surface of  he shell at a substantially constant mass flow rate both of the individual volatile components and totally through such porous polymer section, or (b) transported through the porous polymer shell section by means of capillary action at a substantially constant mass flow rate totally both of the individual volatile components and flowing from said thin shell, the driving force of such molecular transport resulting from a difference in concentration of volatile substance between:     (x)  the gas phase of the inner void of said shell; and (y)  the space immediately adjacent the outer surface of said microporous polymer shell, the said container containing said film ceases to operate, discretely, when said container is placed in an outer air-tight container.  The structure consisting of the two containers; the inner container containing the entrapped volatile substance and the outer container is also a part of our invention.     Basically, our invention involves the aforementioned function as enabled using a polymer shell or film or sheet, monolayer, bilayer or multilayer, (hereinafter referred to as a "membrane") that is defined by having (i) the property of either transporting water vapor at a rate of between about 100 up to 1000 g/m2/day at about 25°C and at about 50% relative humidity at about atmospheric pressure and/or having an air transport rate of 100-20,000 Gurley seconds (Gs); and (ii) a thickness in the range of from about 0.01 mils up to about 20 mils.