Method for controlling evaporation of liquid air freshener and insecticidal compositions

Abstract

A non-aqueous, single phase, non-thickened liquid air freshener or insecticidal composition having a flashpoint of greater than about 62° C. is provided. The composition contains: a) a polar solvent; b) up to about 10 wt % of a non-polar aliphatic hydrocarbon solvent; and c) a fragrance or an insecticide. The composition may be dispensed from a device having a chamber with at least one wall made of a material which enables a vapor of the composition to diffuse out of the chamber.

1 . A method for controlling the evaporation characteristics of a non-aqueous, single phase, non-thickened liquid air freshener or insecticidal composition for release of vapors of the composition through a vapor-permeable membrane into the environment for deodorizing the environment or controlling insects therein for a required period of time, comprising providing a fragrance or insecticide in a solvent mixture comprising: 
 a) a polar solvent; and    b) a non-polar aliphatic hydrocarbon solvent which is present in an amount up to about 10 wt. % based on the total weight of the composition; such that the composition has a flashpoint greater than about 62° C. and will not damage or destroy the membrane.    
     
     
         2 . The method according to  claim 1 , wherein the composition is an air freshener and comprises a fragrance.  
     
     
         3 . The method according to  claim 1 , wherein the polar solvent has an evaporation rate less than about 100 and the non-polar solvent has an evaporation rate less than about 16, both rates being based on a scale in which n-butyl acetate has an evaporation rate of 100.  
     
     
         4 . The method according to  claim 1 , wherein the polar solvent comprises a glycol ether.  
     
     
         5 . The method according to  claim 4 , wherein the polar solvent is selected from the group consisting of a (C 1-4  alkyl)glycol(C 1-4  alkyl)ether, a di(C 1-4  alkyl)glycol(C 1-4  alkyl)ether, a (C 1-4  alkyl)glycol di(C 1-4  alkyl)ether, a di(C 1-4  alkyl)glycol di(C 1-4  alkyl)ether, a tri(C 1-4  alkyl)glycol(C 1-4  alkyl)ether, and mixtures thereof.  
     
     
         6 . The method according to  claim 4 , wherein the polar solvent is selected from the group consisting of 3-butoxypropan-2-ol, propylene glycol monomethyl ether, tripropylene glycol methyl ether, dipropylene glycol methyl ether, dipropylene glycol dimethyl ether, dipropylene glycol n-propyl ether, dipropylene glycol mono n-butyl ether, tripropylene glycol mono n-butyl ether, and propylene glycol n-butyl ether, and mixtures thereof.  
     
     
         7 . The method according to  claim 1 , wherein the non-polar solvent is a C 10-18  alkane or a cycloparaffinic hydrocarbon.  
     
     
         8 . The method according to  claim 1 , wherein a weight ratio of the polar solvent to the non-polar solvent is about 1:1 to about 6:1.  
     
     
         9 . The method according to  claim 8 , wherein the weight ratio is about 2:1 to about 5:1.  
     
     
         10 . The method according to  claim 1 , wherein the non-polar solvent is present in an amount of about 1 to about 10 wt % based on the total weight of the composition.  
     
     
         11 . The method according to  claim 1 , wherein the membrane comprises a polyethylene.  
     
     
         12 . The method according to  claim 1 , wherein the composition has an evaporation rate such that the required period of time is on an order of about 45 days.  
     
     
         13 . The method according to  claim 1 , wherein the solvent mixture leaves no residue upon evaporation, thereby providing an end-of-life indication for the composition.  
     
     
         14 . The method according to  claim 1 , wherein the composition comprises: 
 a) about 15 to about 40 wt % of the polar solvent;    b) about 1 to about 10 wt % of the non-polar solvent; and    c) about 5 to about 80 wt % of the fragrance or insecticide.    
     
     
         15 . The method according to  claim 1 , further comprising packaging the composition in an air freshener or insecticidal device comprising a chamber having at least one membrane wall which is permeable to vapors of the composition.  
     
     
         16 . The method according to  claim 15 , wherein the chamber is charged with about 5 to about 50 grams of the composition.