DESC:Technical field of the Invention:
The present invention relates to a novel controlled release delivery device of porous membrane for release of volatile actives. More particularly, the present invention relates to a pouch made up of semi-rigid substrate having extrusion coating and lamination of porous polymers.

Background of the Invention:
Air fresheners have become a staple in many homes and offices, marketed with the promise of creating a clean, healthy, and pleasant smelling indoor atmosphere. Conventional air fresheners are either in the form of stearate blocks or carrageenan blocks that are used in homes. Liquid air fresheners are also available which comprises of liquid reservoir containing fragrance solution into which porous wick is dipped at the bottom. The fragrance solution travels by capillary action of the porous wick to top emanating surface. However, one problem with liquid air fresheners is leakage during transportation and during its use causing damage to plastic parts that are in contact during use and thereby causing inconvenience to the users.

More recently devices incorporating with hydrophobic polymeric membranes have been developed and commercially available. US Patent No. 4145001 of Weyenberg et al. (March 20, 1979) describes once such device, in the form of, a multi-layer polymeric package for the controlled release of a volatile substance (e.g. deodorizer) sandwiched between layers. The outer layers of the laminate are impermeable to the volatile substance and its vapors and thus prevent escape of vapors as long as the package is sealed. Upon opening the package, delamination occurs at the interface between two selected layers such that the volatile substance is covered only on one side by a layer which is permeable to vapors thereby allowing controlled release of volatile materials.

US4948047 disclose a passive dispenser of volatile liquid fragrance composition from a container thereof. The container has an orifice at its bottommost point and an isotatic hydrophobic polypropylene membrane covering the orifice. The membrane permits passage of the liquid fragrance composition there through in the liquid phase in order to enable the composition of the liquid transmitted through the membrane to be substantially the same as that of the liquid within the container.

Another technology is reported in air freshener devices such as polymer coating on the substrate material of the device. The coatings of polymeric materials can be applied on a variety of substrates using a number of different techniques such as extrusion, dispersion coating and solution application. These coating techniques, which in general are off-line processes, give vast possibilities to form coated, multilayer and laminated structures.

Extrusion coating is the coating of a molten polymer onto a substrate material. It is a versatile coating technique used for the economic application of various polymers, notably polyethylene, onto paperboard, corrugated fiberboard, paper, aluminium foils, cellulose, Non-wovens, or other composite plastic films. Extrusion coating is one of the processes used to produce a large range of thin multilayer structures. In the extrusion coating of polyethylene, a molten web of extruded polymer is applied as a thin coating onto a substrate which is passing continuously through a nip-roll assembly. The substrate may be paper, paper board, polyester film, polypropylene film, aluminium foil, woven fabric, etc.

Hence, there is a need in the art to develop easy to use, easy to manufacture and non-leaking device having porous membrane for controlled release of volatile actives which is made up with extrusion coating, which becomes the objective of the present invention for which protection is sought.

Summary of the Invention:
In accordance with the above, it is an object of the present invention to provide a novel controlled release delivery device made up of semi-rigid substrate having extrusion coating and lamination of porous polymer, for dispensing of volatile actives; wherein extrusion coating can be one or two sided.

Accordingly in an aspect, when the extrusion coating is of one sided, it reduces the exposed porous area, thereby controlling the release and extending the longevity of volatile actives and when the extrusion coating is of two sided then the inner side acts as sealant layer for perfume absorption and outer side functions to regulate and release of the fragrance.

In another aspect, the present invention describes a controlled release delivery device in shape of pouch made up of semi-rigid substrate or porous paper such as Maplitho paper, Poster paper, synthetic paper, Glassine paper, cellulose, cotton linter, cloth, and Non-wovens, having extrusion coating of porous membrane comprising a polymer selected from the group consisting of LLDPE (Linear low-density polyethylene), VLDPE (Very Low Density Polyethylene), LDPE (Low-density polyethylene), HDPE (High density poly ethylene), plastomers, ionomers, Ether-Amide Block Co Polymer, Ethylene co polymers group like EBA (Ethylene butyl acrylate), or EVA (Ethylene-vinyl acetate).

The pouch is used to dispense fragrances, personal perfumes, volatile insecticide/pesticide solutions, pest repellent fluids and/or volatile medicaments.

Brief description of Figures:
Figure 1 exhibits the cumulative weight loss in % verses time in days for the pouch of the present invention in comparison to the presently available porous membranes in the market.

Figure 2: Rectangular cross-section of laminate used for pouch making

Detailed description of the invention:
The invention will now be described in detail in connection with certain preferred and optional embodiments, so that various aspects thereof may be more fully understood and appreciated.

In one embodiment, the present invention describes a novel controlled release delivery device in shape of pouch formed on a heat sealing machine comprises of semi-rigid substrate or porous paper having extrusion coating and lamination made of porous polymers, for dispensing of volatile actives; wherein extrusion coating can be one or two sided. If the extrusion coating is of one side, it reduces the exposed porous area, thereby controlling the release and extending the longevity of volatile actives and if the extrusion coating is of two sides then the inner side acts as sealant layer for perfume absorption and outer side functions to regulate and release of the fragrance.
Accordingly, when the extrusion coating is of two sides, the inner side is non-permeable and outer side is permeable.

The semi-rigid substrate or porous paper are selected from Maplitho paper, Poster paper, synthetic paper, Glassine paper, cellulose, cotton linter, cloth, and Non-wovens, preferably a Maplitho paper.

The porous polymers are selected from the group consisting of LLDPE (Linear low-density polyethylene), LDPE (Low-density polyethylene), VLDPE (Very Low Density Polyethylene), HDPE (High density poly ethylene), Ethylene copolymers group like EVA (Ethylene-vinyl acetate) or EBA (Ethylene Butyl Acrylate), Ether-Amide block co polymers, plastomers and ionomers, preferably, LDPE (Low-density polyethylene).

The density of semi-rigid substrate is in the range of 30 to 180 gsm, preferably, 130 gsm and thickness of porous polymer is in the range of 10 to 85gsm, preferably, 40gsm.

The function of the porous polymer membrane is to release volatile actives into the ambient atmosphere, since it is permeable to the vapors, thereby allowing controlled release of the vapors over a period of time. The porous membrane also acts as sealing layer to seal the edges of the pouch and prevent leakages.

The pouch is further filled with formulation of fragrance or volatile actives in the form of liquid, gel, solid or semi-solid form and sealed after filling.

The formulation of fragrance or volatile actives filled in the pouch is carefully chosen, for example, fragrance or volatile insecticidal actives are selected from a mixture of volatile fragrance oil, natural essential oils, synthetic aroma chemicals and/or insecticide molecules, optionally volatile and nonvolatile solvents such as organic non polar solvents of aliphatic hydrocarbons, glycols and thickening agent such as cellulose, silica acrylic polymeric thickeners and rheology modifiers. The choice of fragrance and its chemistry is critical for performance of the product. The rate of evaporation of the fluid inside the pouch depends on the characteristics of the membrane and the chemical composition of volatile actives.

The volatile actives which can be dispensed include fragrances, personal perfumes, volatile insecticides, pesticides, pest repellent fluids and/or volatile medicaments.

The filled pouch is thereafter packed in non-porous, non-permeable polymeric or metallic laminate materials to prevent volatilization of fluid until it is ready to be actuated. The nonporous polymeric packaging made of barrier laminates allow volatile fluid contained in the cell to diffuse only through the permeable membrane at a controlled rate after it is removed from the pouch and meant for end use.

In accordance with the above, in a preferred embodiment, the present invention discloses a controlled release delivery device in shape of pouch comprises of semi-rigid substrate or porous paper selected from Maplitho paper, Poster paper, Glassine paper, having density of 30-180gsm, preferably, 130gsm and extrusion coating and lamination of porous polymers selected from the group consisting of LLDPE (Linear low-density polyethylene), LDPE (Low-density polyethylene) or EVA (Ethylene-vinyl acetate) having thickness of 10 to 85gsm, preferably, 40gsms; wherein extrusion coating can be two sided i.e. inner side acts as sealant layer for perfume absorption and outer side functions to regulate and release of the fragrance.

In another preferred embodiment, the present invention discloses a controlled release delivery device in shape of pouch comprises of semi-rigid substrate having one sided extrusion coating and lamination of porous polymers; wherein said one sided extrusion coating reduces the exposed porous area, thereby controlling the release and extending the longevity of volatile actives.

In one sided extrusion coating comprises the semi-rigid substrate or porous paper may be optionally coated with non-permeable barrier coating selected from acrylic polymer, PVDC (Polyvinylidene chloride), PET (Polyethylene terephthalate), or foil stamping, or coated with any barrier material that can block the semi-rigid substrate or porous paper and reduce the release surface area partially. The reduction in release will be dependent on area covered by barrier coating.

The controlled release delivery device in shape of pouch of the present invention has variable sizes for example, a size of 8.0 x 9.0 cm, which is formed by heat sealing process. The process comprises;
a) Heat sealing of a pouch comprising semi-rigid substrate having density of 30-180gsm with extrusion coating and lamination of porous polymers having thickness of 10-85gsm; wherein the sealing is on three sides;
b) adding 5-20gm of mixture of fragrance or volatile actives, suitable solvent and thickening agent into the pouch of step (a), followed by subsequent sealing on the fourth side; and
c) sealing of pouch of step (b) into another pouch made up of Polyethylene Terephthalate (PET), HSL PET (Heat sealable Polyethylene Terephthalate) or other barrier laminates for storage/ to prevent loss of odorous components before use.

The invention also discloses use of controlled release delivery device, wherein, internal paper was removed from the barrier non permeable film and the paper membrane pouch was weighed immediately. The pouch was hung open into the atmosphere. The weight loss due to volatilization of the perfume was measured and recorded. The temperature was ambient temperature (25°C +/- 5°C).

The product of the present invention can be placed in olfactory booths and its fragrance intensity is rated by expert odor panel during entire period of use of 30 days. The scores substantiated the product performance as observed in the weight loss data obtained.

The invention further described as in Figure 1 exhibits the cumulative weight loss in % verses time in days for the pouch in comparison to the presently available porous membranes in the market. The performance in terms of weight loss data over a period of 30 days is tracked and shown in Figure 1. It is exhibited from Figure 1 that, the % of fragrance release in paper membrane is about 90% in 30 days; whereas % of fragrance release in LDPE (Low-density polyethylene) membrane is around 70% in 30 days.

The representation shown in rectangular cross-section (Figure 2) which is simple in method of manufacturing; however, other shapes such as a square, circular or triangle, bottom and/or side gauzetted are also possible that may be desired for aesthetic reasons.
This novel delivery mechanism of the present invention is easy to use and easy to manufacture, non-leaking and is an economical solution for use as air fresheners/ insecticides. The volatile actives delivery device of the present invention is simple in material and process of manufacturing and may be mass-produced at a relatively low cost.

The typical example illustrating the embodiment of the present invention is provided; however, this is exemplary only and should not be regarded as limiting the elements of the present invention.

Example 1
A controlled release rectangular pouch having size of 8.0 x 9.0 cm comprises of maplitho paper of 130 gsm and extrusion coating and lamination of LDPE of 40gsms, formed by heat sealing process, which seals the edges on three sides. Adding 10gm of mixture comprises of volatile actives, suitable solvent and thickener, into the pouch and subsequently sealed on the fourth side. Sealing of said pouch into another pouch made up of Polyethylene Terephthalate (PET) for storage before use.

Example 2
A controlled release rectangular pouch having size of 8.0 x 9.0 cm comprises of poster paper of 45 gsm and extrusion coating and lamination of LDPE & LLDPE of 40 gsms, formed by heat sealing process, which seals the edges on three sides. Adding 10gm of mixture comprises of volatile actives, suitable solvent and thickener, into the pouch and subsequently sealed on the fourth side. Sealing of said pouch into another pouch made up of Polyethylene Terephthalate (PET) for storage before use.

Example 3
A controlled release rectangular pouch having size of 8.0 x 9.0 cm comprises of Glassine paper of 45 gsm and extrusion coating and lamination of LDPE of 40 gsms, formed by heat sealing process, which seals the edges on three sides. Adding 10gm of mixture comprises of volatile actives, suitable solvent and thickener, into the pouch and subsequently sealed on the fourth side. Sealing of said pouch into another pouch made up of Polyethylene Terephthalate (PET) for storage before use.
,CLAIMS:1. A novel controlled release delivery device for dispensing of volatile actives comprising a semi-rigid substrate or porous paper having one or two sided extrusion coating and lamination made of porous polymers;
wherein when the extrusion coating is of one sided, it reduces the exposed porous area, thereby controlling the release and extending the longevity of volatile actives and
wherein when the extrusion coating is of two sided, the inner side of coating acts as sealant layer for perfume absorption; and outer side of coating functions to regulate and release of the fragrance.

2. The controlled release delivery device as claimed in claim 1, wherein when the extrusion coating is of two sided, the inner side is non-permeable and outer side is permeable.

3. The controlled release delivery device as claimed in claim 1, wherein semi-rigid substrate or porous paper selected from maplitho paper, poster paper, synthetic paper, glassine paper, cellulose, cotton linter, cloth and Non-wovens, having density of 30-180gsm.

4. The controlled release delivery device as claimed in claim 1, wherein porous polymers selected from the group consisting of LLDPE (Linear low-density polyethylene), LDPE (Low-density polyethylene), VLDPE (Very low density polyethylene), HDPE (High density poly ethylene), EVA (Ethylene-vinyl acetate), EBA (Ethylene butyl acrylate), Ether-Amide block co polymers, and other polymers having thickness of 10-85gsm.

5. The controlled release delivery device as claimed in claim 1 and 3, wherein the semi-rigid substrate is maplitho paper having density of 130 gsm.

6. The controlled release delivery device as claimed in claim 1 and 4, wherein the porous polymer is LDPE (Low-density polyethylene) having thickness of 40 gsms.

7. The controlled release delivery device as claimed in claim 1, wherein one sided extrusion coating comprises semi-rigid substrate or porous paper that optionally coated with non-permeable barrier coating selected from acrylic polymer, PVDC (Polyvinylidene chloride), PET (Polyethylene terephthalate), or foil stamping, or coated with any barrier material that can block the semi-rigid substrate or porous paper and reduce the release surface area partially.

8. The controlled release delivery device as claimed in claim 1 to 3, wherein the semi-rigid substrate or porous paper filled with formulation of fragrance or volatile insecticidal actives that are selected from mixture of volatile fragrance oil, natural essential oils, synthetic aroma chemicals and/or insecticide molecules.

9. The controlled release delivery device as claimed in claim 8, wherein the formulation of fragrance or volatile actives is in the form of liquid, gel, solid or semi-solid form.

10. The controlled release delivery device as claimed in claims 8 and 9, wherein the fragrance or volatile actives include personal perfumes, volatile insecticides, pesticides, pest repellent fluids and/or volatile medicaments.

11. The controlled release delivery device as claimed in any of the preceding claims; wherein the device is in the form of a pouch having rectangular, square, circular or triangular, bottom and/or side gauzetted shape.

12. The controlled release delivery device as claimed in any of the preceding claims; wherein the device is formed by heat sealing process.

13. A process for preparation of controlled release delivery device as claimed in claim 1 and 2, wherein the process comprises,
a) Heat sealing of a pouch comprising semi-rigid substrate having density of 30-180gsm with extrusion coating and lamination of porous polymers having thickness of 10-85 gsm; wherein the sealing is on three sides;
b) adding 5-20gm of mixture of fragrance or volatile actives, suitable solvent and thickening agent into the pouch of step (a), followed by subsequent sealing on the fourth side; and
c) sealing of pouch of step (b) into another pouch made up of Polyethylene terephthalate (PET), HSL PET (Heat sealable Polyethylene Terephthalate) or other barrier laminates for storage/prevent loss of odorous components before use.

14. The process for preparation of controlled release delivery device as claimed in claim 13, wherein the suitable solvents are selected from organic non polar solvents of aliphatic hydrocarbons, glycols and thickening agents are selected from cellulose, silica acrylic polymeric thickeners and rheology modifiers.