Reduction in stress cracking of films

Abstract

Methods and packages for storing film strips while reducing or eliminating stress cracking during storage, including use of packages having an inner surface made from polymeric materials exhibiting various physical properties and including films and pouches that are annealed.

What is claimed is: 
     
         1 . A pouch for storing a film comprising:
 a laminate of at least one first layer and at least one second layer, and   a cavity comprising a film which has been annealed to reduce stress-cracking of said film, said film comprising at least one polymer and at least one active,   wherein said film exhibits less stress-cracking when annealed than when not annealed.   
     
     
         2 . The pouch of  claim 1 , wherein the at least one polymer is selected from the group consisting of polyethylene oxide, hydroxypropylmethylcellulose, and combinations thereof. 
     
     
         3 . The pouch of  claim 1 , wherein the at least one first layer or the at least one second layer comprise low density polyethylene, ethylene acrylic acid, and combinations thereof. 
     
     
         4 . The pouch of  claim 1 , wherein the film does not exhibit stress cracking or does not exhibit substantial stress cracking from about 1 month to about 3 years. 
     
     
         5 . The pouch of  claim 4 , wherein the film does not exhibit stress cracking or does not exhibit substantial stress cracking from about 1 month to about 2 years. 
     
     
         6 . The pouch of  claim 1 , said film further comprising an additive selected from the group consisting of surfactants, plasticizers, and combinations thereof. 
     
     
         7 . A method for reducing stress cracking in a film comprising: 
     
     
         8 . (a) providing a film comprising at least one polymer and at least one active;
 (b) annealing the film to reduce stress-cracking of the film; wherein said film exhibits reduced stress cracking as a result of said annealing.   
     
     
         9 . The method of  claim 7 , wherein said film further comprises an additive selected from the group consisting of surfactants, plasticizers, and combinations thereof. 
     
     
         10 . The method of  claim 9 , wherein the additive is present in an amount from about from about 5% by wt. to about 30% by weight of the film. 
     
     
         11 . The method of  claim 7 , wherein the film does not exhibit stress cracking or does not exhibit substantial stress cracking for from about 1 month to about 3 years. 
     
     
         12 . The method of  claim 7 , wherein the film does not exhibit stress cracking or does not exhibit substantial stress cracking for from about 1 month to about 2 years. 
     
     
         13 . The method of  claim 7 , wherein the film is annealed by applying heat to the film at temperatures of from about 40° C. to about 90° C. 
     
     
         14 . The method of  claim 7 , wherein the film is heated for from about 0.5 minutes to about 60 minutes. 
     
     
         15 . A method for reducing stress cracking in a film comprising a continuous and uniform product comprising the steps of:
 (a) preparing a film-forming matrix comprising a solvent, an active and a polymeric material;   (b) casting said film-forming matrix and drying said film-forming matrix to form a dried film; and   (c) annealing said dried film to relieve stresses imposed by the drying process.   
     
     
         16 . The method of  claim 15 , wherein the film is annealed at a temperature between 40 degrees C. and 90 degrees C. 
     
     
         17 . The method of  claim 15 , wherein the film is annealed at a time between 0.5 minutes and 60 minutes. 
     
     
         18 . A method for reducing stress cracking in a film comprising a continuous and uniform product comprising the steps of:
 (a) preparing a film-forming matrix comprising a solvent, an active and a polymeric material;   (b) casting said film-forming matrix and drying said film-forming matrix to form a dried film;   (c) packaging said dried film in a pouch to form a packaged film; and   (d) annealing said pouched film to relieve stresses imposed by the drying process.   
     
     
         19 . The method of  claim 18 , wherein the packaged film is annealed at a temperature between 40 degrees C. and 90 degrees C. 
     
     
         20 . The method of  claim 18 , wherein the packaged film is annealed at a time between 0.5 minutes and 60 minutes.
 The method of  claim 15 , wherein the film is annealed by removing the film from the substrate, annealing the film and rewinding the film onto a substrate.   
     
     
         22 . The method of claim  21 , wherein the film is annealed at a temperature between 40 degrees C. and 90 degrees C. 
     
     
         23 . The method of claim  21 , wherein the film is annealed at a time between 0.5 minutes and 60 minutes 
     
     
         24 . A continuous and uniform film product with reduced stress cracking, wherein said film product is formed by a process comprising:
 (a) casting a film-forming matrix comprising a solvent, an active and a polymeric material;   (b) drying said film-forming matrix to form a dried film; and   (c) annealing said dried film to relieve stresses imposed by the drying process to form a reduced stress cracked film.   
     
     
         25 . The film of  claim 24 , wherein the film is annealed at a temperature between 40 degrees C. and 90 degrees C. 
     
     
         26 . The film of  claim 24 , wherein the film is annealed at a time between 0.5 minutes and 60 minutes. 
     
     
         27 . A continuous and uniform film product with reduced stress cracking, wherein said product is formed by a process comprising:
 (a) casting a film-forming matrix comprising a solvent, an active and a polymeric material;   (b) drying said film-forming matrix to form a dried film;   (c) packaging said dried film in a pouch to form a packaged film; and   (d) a annealing said pouched film to relieve stresses imposed by the drying process to form a reduced stress cracked film.   
     
     
         28 . The film of  claim 27 , wherein the packaged film is annealed at a temperature between 40 degrees C. and 90 degrees C. 
     
     
         29 . The film of  claim 27 , wherein the packaged film is annealed at a time between 0.5 minutes and 60 minutes. 
     
     
         30 . The film of  claim 24 , wherein the film is annealed by removing the film from the substrate, annealing the film and rewinding the film onto a substrate. 
     
     
         31 . The film of  claim 30 , wherein the film is annealed at a temperature between 40 degrees C. and 90 degrees C. 
     
     
         32 . The film of  claim 30 , wherein the film is annealed at a time between 0.5 minutes and 60 minutes 
     
     
         33 . The film of  claim 24  which is intact with no cracking after 3 weeks in the package 
     
     
         34 . The film of  claim 24  intact with no cracking after 2 months in the package 
     
     
         35 . The film of  claim 24  intact with no cracking after 6 months in the package 
     
     
         36 . The film of  claim 24  intact with no cracking after 12 months in the package 
     
     
         37 . The film of  claim 24  intact with no cracking after 2 years in the package 
     
     
         38 . The film of  claim 24  intact with no cracking after 3 years in the package 
     
     
         39 . The film of  claim 30  which is intact with no cracking after 3 weeks in the package 
     
     
         40 . The film of  claim 30  intact with no cracking after 2 months in the package 
     
     
         41 . The film of  claim 30  intact with no cracking after 6 months in the package 
     
     
         42 . The film of  claim 30  intact with no cracking after 12 months in the package 
     
     
         43 . The film of  claim 30  intact with no cracking after 2 years in the package 
     
     
         44 . The film of  claim 30  intact with no cracking after 3 years in the package