Packaging for controlled release of volatile substances
AssigneeAmerican Can Company
InventorsRobert J. Weyenberg, Don W. Seidler
Life of this patent
Estimating the term…
Abstract
A package having plural layers with a quantity of volatile substance such as deodorizer sandwiched between the layers. The outer layers of the laminate are impermeable to the substance and its vapors, and thus prevent escape of the vapors as long as the package is sealed. Upon opening of the package, delamination occurs at the interface between two selected layers such that the volatile substance is covered on one side only by a layer of material which is permeable to the vapors, thereby allowing controlled release of the vapors over a period of time. A process for production of such packages is also disclosed.
Claims26
A package selectively providing controlled release of vapors from a volatile substance, comprising:
- (a) first and second outer layers of material impermeable to the vapors of the volatile substance;
- (b) first and second inner layers of thermoplastic material sealed together in a bond formed around a quantity of the volatile substance, the first of said layers being permeable to the vapors of the volatile substance and the second of said layers being adhered to one of said outer layers;
- (c) a release layer adhered to said permeable inner layer and to the other of said outer layers, the adhesion of said release layer to said permeable layer being less than the adhesion of the bond between said inner layers, less than the adhesion between said release layer and said outer layer adhered thereto, and less than the adhesion between said second inner layer and said outer layer adhered thereto, and wherein the cohesion of said permeable layer at the bond is less than its adhesion to said second inner layer, whereby when a user pulls the package apart by pulling apart the portions of the package where said inner layers are not bonded, said permeable layer will pull apart at the bond and will remain adhered to said second inner layer and will delaminate from said release layer, such that the volatile substance will be covered only by said permeable layer to allow the diffusion of vapors from the volatile substance therethrough at a selected controlled rate over a period of time.
A process for producing a package which provides selective controlled release of vapors from a volatile substance, comprising the steps of:
- (a) laminating together a release layer and a permeable inner layer at a selected adhesive strength between the two layers, said permeable layer being formed of a thermoplastic material which is permeable to the vapors of the volatile substance;
- (b) laminating the release layer side of the release layer-permeable layer laminate to a first outer layer to form a first laminated panel, the outer layer being formed of a material which is impermeable to the vapors of the volatile substance, the adhesion between the release layer and the impermeable layer being greater than the adhesion between the release layer and the permeable layer;
- (c) laminating a second inner thermoplastic layer onto a second impermeable layer to form a second laminated panel, the adhesion between the second inner layer and the second impermeable layer being greater than the adhesion between the permeable layer and the release layer of the first panel;
- (d) placing the first and second panels together over a quantity of the volatile substance with the permeable layer and the second inner layer in facing relation;
- (e) forming a heat bond between the first and second panels with the bond surrounding the quantity of volatile substance, the heat bond being formed such that the adhesion of the release layer to the permeable layer is less than the adhesion of the bond between the permeable layer and the second inner layer, less than the adhesion between the release layer and the impermeable layer adhered thereto, and less than the adhesion between the second inner layer and the impermeable layer which is adhered thereto.
Dependencies are inferred from the claim text.