CA2070936C - A scented air freshening device and method for making the same - Google Patents

Abstract

A method of producing an air freshening device, capable of attachment to an existing air filter, comprising the steps of forming a mixture of effective amounts of a fragrant material, a polymer and a volatile solvent for the fragrant material and the polymer, applying the mixture to a substrate through which air may pass, allowing the solvent to evaporate to leave a fragrant residue on the substrate, and attaching the substrate to an existing air filter device capable of attachment to an existing air filter, comprising a residue of effective amounts of a fragrant material and polymer applied to a piece of foam rubber and means for attaching said device to the existing air filter is also provided.

Description

A SCENTED AIR FRESHENING DEVICE
AND METHOD FOR MAKING THE SAME
s This is related to our co-pending Canadian application File No. 2,032,142 filed March 1, 1990.

BACKGROUND OF THE INVENTION

The present invention relates to an air freshening device. More particularly, the invention relates to an air freshening device having a fragrant polymeric residue on a substrate through which air may pass and which may be used in a mechanical forced air type ventilation system by attachment to an existing air filter.

Compositions and devices for releasing fragrance over a long period of time are known. For example, U.S. Patent No. 4,118,226 discloses placing a solid aromatic medium in a perforated case which in turn is placed in an air circulation system. U.S. Patent No. 4,604,114 similarly discloses placing large solid rods of fragrant scented material in an air circulation system. U.S. Patent No.
4,563,333 discloses a deodorizing fitting for an air filter in which a rectangular envelope of perforated cardboard with a deodorizing insert therein is adhered to the corner of the filter. U.S. Patent No. 4,425,321 discloses deodorant compositions for treating textiles such as towels or other supports to cause them to act as deodorants. U.S. Patent No. 4,065,262 discloses utilizing a plurality of containers for holding an air freshening composition positioned in the air filter. U.S. Patent No.
4,523,870 relates to an aroma dispensing cartridge placed in front of an air vent. U.S. Patent No. 4,735,358 discloses fragrant material placed on a tape from which the material vaporizes when the tape is run across a tape head by drive means.

A problem exists, however, in that each of these patents disclose devices which interfere with the flow of air through the circulation system. Furthermore, none of the inventions in these patents can be employed in a pre-existing filter system. Rather, specifically designedframes or casings must be employed to hold the fragrant structures.

There exists a need, therefore, for an air freshening device which may be used in a pre-existing air circulation system for attachment to an existing air filter and which does not interfere with the circulation of air through that system.

SUMMARY OF THE INVENTION
The present invention relates to an air freshening device comprising a perforated or porous substrate having a residue of polymer and fragrant material thereon. The device is attached to an air filter through which air passes or can be placed within a vehicle, such as an automobile, in order to impart a fragrance to the enclosed space of the vehicle.

To place the residue containing material on the substrate, two different methods are used. Method I uses a solution prepared by dissolving a fragrant liquid in a volatile solvent. The solution is then mixed with a polymeric material which forms a viscous solution which is then applied to a perforated substrate. The solvent is evaporated and a fragrant solid residue is deposited on the perforated substrate, forming the fragrant air freshening device. Method II uses a hot melt mixture prepared by dissolving a fragrant liquid in a melted polymer. The hot melt mixture is then deposited on a perforated substrate, but not to the extent that the air flow therethrough is blocked or restricted. Upon cooling, ;~ 3 a fragrant solid residue is deposited on the perforated substrate, forming a fragrant air freshening device.

The invention in broad aspect provides a device for scenting air in a forced air ventilation system. The device comprises an air permeable substrate having a plurality of interstices therein for communicating air through the substrate. A solid fragrant residué is formed on the substrate and permeates into at least some of the substrate interstices so that a fragrant scent slowly releases when the substrate having the solid fragrant residue formed thereon is positioned in a forced air ventilation system. An attacher is provided for interconnecting the substrate having the solid fragrant residue formed thereon to a face of an air filter in a forced air ventilation system.

The resulting fragrant air freshening device may be used in two different ways. One way is to attach the fragrant air freshening device directly to any air filter in a heating or air conditioning system. Air circulating through the system passes unobstructed through the filter with the fragrant air freshening device and becomes scented with fragrance. Because the fragrant air freshening device is attached to the air filter, the present invention may be employed with no structural modifications to either the air circulation system or the filters.

An alternative embodiment involves placing the fragrant air freshening device within an automobile, such as under the seat. The fragrance slowly diffuses into the air causing the air in the automobile to become scented.

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Therefore, it is an object of the present invention to provide an air freshening device which may be utilized in a pre-existing air circulation system for attachment to an existing air filter which does not interfere with the flow of air through the system.

Another object is to provide an air freshening means for use under the seat of an automobile or other enclosed space providing scented air from an unobtrusive source over an extended period of time.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a top plan view of a fragrant air freshening device constructed according to the present invention;

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~ .a Figure 2 is a perspective view of a fragrant air freshening device attached to an air filter; and Figure 3 is a top plan view of a fragrant air freshening device to be used in an automobile.

DETAILED DESCRIPTION OF THE INVENTION

Methods and compositions for producing an air freshening device are provided herein.

This invention provides a method of producing an air freshening device that can be attached to an existing air filter in an air filtration system or can be placed in any enclosed space. The steps of producing the air freshening device include mixing effective amounts of a fragrant material, a polymer and a solvent for the fragrant material and the polymer and applying the mixture to a substrate through which air can pass. Allowing the solvent to evaporate leaves a fragrant residue on the substrate which may then be attached to an existing air filter. The preferred means of attachment is a barbed shaft, although any other means for attaching the substrate to an existing air filter can be used, such as glue or clips. The substrate to which the fragrance is applied is preferably a piece of foam rubber, but can be fibrous filter material, a mesh material, or any other porous or perforated substrate through which air can pass.

The fragrant material used in the method of this invention is preferably a liquid fragrance but can also be in powder form. The fragrant material may be selected from among commercially available fragrances such as honeysuckle fragrance or pine fragrance available from International Fragrance and Technologies, Inc. (Woodstock, Georgia).

The polymer used in the method of producing an air freshening device is preferably a mixture of hydroxypropylcellulose and polyvinylpyrrolidone vinyl acetate, in the preferred 2:1 ratio or in ratios ranging from 4:1 to 1:4. The method is not limited to one mixture and can be used with hydroxypropylcellulose alone or any other suitable water-soluble, non-ionic polymer or other mixtures of such polymers. Alternatively, non-water soluble or ionic polymers capable of being dissolved in the solvent can be used. The polymer can also be a hot melt adhesive such as ethylene vinyl acetate.

The preferred solvent for use in the method of this invention is ethyl alcohol, but any non-toxic solvent can be used.

The preferred ratio of fragrant material to polymer is 1:1, but can range effectively from about 1:4 to about 4:1 by weight. An effective amount of fixative and plasticizer can also be added to the mixture applied to the substrate in this invention.

An additional method of producing an air freshening device includes the steps of forming a mixture of a polymer and plasticizer, heating the mixture until it melts, adding a fragrant material to the mixture, mixing until the mixture is homogenous, applying the mixture to a substrate through which air may pass and allowing the mixture to cool to leave a fragrant residue on the substrate.

The polymer of this method is preferably a hot melt adhesive, such as ethylene vinyl acetate. However, any polymer that is miscible with the fragrance when melted, can act as a carrier for the fragrance and can control the release of the fragrance.

The preferred plasticizer of this method is polybutene plasticizer, but any plasticizer can be used that will regulate the hardness and controlled release properties of the fragrant residue.

The invention also provides a fragrant air freshening device that includes effective amounts of fragrant material and polymer applied to a substrate through which air passes and means for attaching the substrate to an existing air filter. The substrate can be any porous or perforated material. Any suitable polymer in an effective amount to act as a controlled release carrier for the fragrant material can be used. The fragrant material can be any suitable fragrance, in liquid or solid form so long as it can be applied to the substrate and released in a controlled manner. The devices of this invention can be used in a method of freshening air in an enclosed space, which includes the steps of placing the fragrant air freshening device in the enclosed space and allowing the fragrant material to diffuse into the enclosed space, thus imparting a freshness to the enclosed space. The enclosed space contemplated by this invention can be an automobile, closet or any other space where air freshening is desired.

Figure 1 illustrates a fragrant air freshening device 10 consisting of a perforated substrate 11, which can be polyurethane foam (foam rubber), to which solid residue 12, consisting of polymer and fragrant liquid, has been applied. A device 13 used for attaching the fragrant air freshening device to the air filter is also shown. Device 13 is a barbed shaft that can be pushed through the foam or fiber of the air freshening device into the existing air filter to attach the device to the filter.

Figure 2 illustrates a conventional air filter 14 of the commercially available kind typically provided in a receiving slot in an air circulation system with a , . , fragrant air freshening device 10 attached by a device 13.
The filter 14 is comprised of fibrous filtering material 15, such as a textile material or other woven fibers that arrest particles in the interstices until they are clogged, and a rigid or semi-rigid frame 16 about the periphery of the material 15 for holding the filtering material 15 in position. A mesh 17 for further maintaining the filtering material 15 within the frame 16 is also provided, although the air freshening device can be attached to any commercially available air filter, both residential and commercial.

Figure 3 illustrates a fragrant air freshening device 18 consisting of a perforated or porous substrate 19, which is foam rubber, paper or a fibrous or mesh material, to which solid residue 20, consisting of polymer and fragrant liquid, has been applied.

To provide the residue containing material 12 and 20 of the fragrant air freshening device 10 and 18 which is applied to the perforated substrate 11 and 19, two different methods are used.

Method I
In method I a fragrant liquid is dissolved in a volatile solvent. A mixture of polymers is then added to the fragrant liquid/solvent with vigorous stirring, and the resulting mixture allowed to stand until homogenous.
The viscosity of the solution can be regulated by adjusting the quantity of solvent initially used. The solution is then applied to the perforated substrate 11 and 19 and allowed to dry. Upon drying, the solid, fragrant residue 12 and 20 becomes deposited upon the perforated substrate 11 and 19 (i.e., on the fibers on the substrate but not the interstitial cavities) producing a fragrant air freshening device 10 and 18.

Method I for preparing a fragrant air freshening device 10 and 18 is as follows: Any dissolvable fragrant material may be used, including honeysuckle and pine. It is preferable that a fragrant liquid be used, such as commercially available fragrances. Likewise, any polymer may be used so long as it dissolves in the solvent and can act as a carrier and controlled release device for the fragrance. However, a mixture of polymers such as hydroxypropylcellulose (HPC) and polyvinylpyrrolidone vinyl acetate (PVA) is preferred. This polymeric mixture in a 2:1 (HPC:PVA) ratio by weight has been found to produce a film with desired hardness and controlled release properties. A range of ratios between 4:1 and 1:4 can also be used. It has been found that a ratio of approximately 1:1 fragrant liquid to polymeric mixture (by weight) is preferred, although the ratio may be as high as 2:1 fragrant liquid to polymeric mixture. By varying the ratio of fragrant liquid to polymer, a device with light, medium or heavy scents may be produced.
The solvent is preferably non-toxic. Furthermore, it should have a low boiling point so that it is volatile and evaporates rapidly. Ethyl alcohol has been found to be a particularly suitable solvent.
The solution may be applied to the perforated substrate 11 and 19 in virtually any manner so long as fragrant residue 12 and 20 is formed on the final product.
For example, the solution may be pumped directly onto the perforated substrate 11 and 19.

The resulting fragrant air freshening device 10 and 18 may be used in two different ways. One way is to attach the fragrant air freshening device 10 to air filter 14 with barbed shaft 13, and as air passes through air filter 14, the fragrance from the fragrant air freshening device 10 imparts a pleasant odor to the circulating air.

The other way is to place the fragrant air freshening device 18 under the seat of an automobile. The fragrance slowly diffuses into the air causing the air in the automobile to become scented.

Method II

Method II for preparing a fragrant air freshening device 10 and 18 is as follows: a fragrant liquid is added to a melted polymer or polymeric mixture and the mixture is stirred until homogeneous. The mixture is then applied to the perforated substrate 11 and 19 and allowed to cool. Upon cooling, the solid fragrant residue 12 and 20 becomes deposited upon the perforated substrate 11 and 19, producing a fragrant air freshening device 10 and 18.

Any dissolvable fragrant material may be used, including honeysuckle and pine. It is preferable that a fragrant liquid be used. Likewise, any polymer may be used as long as when it is melted it is miscible with the fragrant liquid, and can act as a carrier and controlled release device for the fragrance. However, a hot melt adhesive (ethylene vinyl acetate copolymer) is preferred.
Any plasticizer may be used in order to regulate the hardness and controlled release properties of the fragrant residue 12 and 10. However, polybutene plasticizer is preferred. It has been found that a ratio of approximately 1:2.3:5 of plasticizer to hot melt adhesive to fragrant liquid by weight is preferred, although the ratio may vary by as much as 1:6:7.56 of plasticizer to hot melt adhesive to fragrant liquid. By varying the ratios of plasticizer, hot melt adhesive, and fragrant liquid, a device with light, medium or heavy scents may be produced.

The polymer-fragrant liquid mixture may be applied to the perforated substrate 11 and 19 by pumping from a hot melt glue gun or by any other effective means.

The following are illustrative examples of two methods for producing the fragrant air freshening device 10 and 18 of the present invention.

Example I (Method I) 2896 g of honeysuckle fragrant liquid is dissolved in 6037 g of ethyl alcohol. 1934 g of hydroxypropylcellulose and 1934 g of 50~ polyvinylpyrrolidone vinyl acetate solution in ethyl alcohol is added to the solution with stirring. The resulting mixture is stirred three hours at room temperature in order to completely dissolve the hydroxypropylcellulose. The solution is then pumped onto a piece of polyurethane foam (foam rubber) such as 6" x 6"
x 1/4" or 3" x 3" x 1/4". After approximately four hours at room temperature the solvent evaporates from the solution and a solid fragrant residue remains on the fibers of foam rubber so that the air passages are not restricted. The fragrant residue causes minimum change in the velocity of air passing through the foam rubber.

Example II (Method II) 27 g of hot melt adhesive (ethylene vinyl acetate copolymer) and 3 g of polybutene plasticizer is heated until melting occurs (about 250~ F). 45 g of honeysuckle fragrant liquid is warmed to between 70~ F and 80~ F. The warm fragrant liquid is added to the melted hot melt adhesive and stirred until a homogeneous mixture results.
This mixture is poured onto a piece of polyurethane foam (foam rubber). Within 5 minutes the mixture cools and a solid fragrant residue remains on the piece of foam rubber. The fragrant residue causes minimum change in the velocity of alr passing through the foam rubber.

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Claims (20)

1. A device for scenting air in a forced air ventilation system, comprising:
an air permeable substrate having a plurality of interstices therein for communicating air through the substrate;
a solid fragrant residue formed on the substrate and permeating into at least some of the substrate interstices so that a fragrant scent slowly releases when the substrate having the solid fragrant residue formed thereon is positioned in a forced air ventilation system;
and an attacher for interconnecting the substrate having the solid fragrant residue formed thereon to a face of an air filter in a forced air ventilation system.

2. The device as recited in claim 1, wherein the solid fragrant residue is a residue of a substantially homogeneous solution applied to the substrate, which contains a solid dissolved in a solvent and an effective amount of a fragrant material.

3. The device as recited in claim 2, wherein the solid fragrant residue is formed by evaporating at least some of the solvent from the substantially homogeneous solution on the substrate.

4. The device as recited in claim 2, wherein the solid dissolved in the solvent is a polymeric material.

5. The device as recited in claim 4, wherein the polymeric material is selected from the group consisting of hydroxypropylcellulose, polyvinyl-pyrrolidone, and mixtures thereof.

6. The device as recited in claim 5, wherein the fragrant material is a fragrant oil.

7. The device as recited in claim 6, wherein the effective amount of the fragrant material being present in the substantially homogeneous solution in a ratio (by weight) of solid to fragrant material ranging from about 1:4 to 4:1.

8. The device as recited in claim 7, wherein the solvent comprises ethyl alcohol.

9. The device as recited in claim 2, wherein the fragrant material comprises a fragrant oil.

10. The device as recited in claim 9, wherein the fragrant oil being present in the substantially homogeneous solution in a ratio (by weight) of solid to fragrant oil ranging from about 1.4 to 4:1.

11. The device as recited in claim 2, wherein the solvent comprises ethyl alcohol.

12. The device as recited in claim 1, wherein the solid fragrant residue is formed on the substrate by:
applying a substantially homogeneous solution containing a meltable solid and an effective amount of a fragrant material to the substrate;
and cooling the homogeneous solution on the substrate.

13. The device as recited in claim 12, wherein the meltable solid is a polymeric material.

14 14. The device as recited in claim 13, wherein the effective amount of the fragrant material being present in the substantially homogeneous solution in a ratio (by weight) of solid to fragrant material ranging from about 1:4 to 4:1.

15. The device as recited in claim 12, wherein the polymeric material is a hot melt adhesive.

16. The device as recited in claim 15, wherein the hot melt adhesive comprises ethylene vinyl acetate.

17. The device as recited in claim 12, wherein the effective amount of the fragrant material being present in the substantially homogeneous solution in a ratio (by weight) of solid to fragrant material ranging from about 1:4 to 4:1.

18. The device as recited in claim 12, wherein the fragrant material is a fragrant oil.

19. The device as recited in claim 18, wherein the effective amount of the fragrant oil being present in the substantially homogeneous solution in a ratio (by weight) of solid to fragrant material ranging from about 1:4 to 4:1.

20. The device as recited in claim 19, wherein the meltable solid is a polymeric material.