IE46693B1 - Air fresheners - Google Patents

Abstract

ALKYL PHENOL ETHER OF POLYETHYLENE GLYCOL AS STABILIZER OF AIR FRESHENER Compositions of fragrance oils are stabilized with respect to potency and aesthetic quality toward the effects of heat and age by including in the formulations a quantity of alkylphenol ethers of polyethylene glycol, or more specifically, alkyl phenoxy polyethoxy ethanols wherein the polyether chain averages from 5 to 13 moles of ethylene oxide, and the alkyl portion of the molecule ranges from 6 to 20 carbon atoms. The alkyl portion of the molecule may be branched, unbranched, saturated or unsaturated. The oils are stabilized in respect to durability or intensity of odor with time and are rendered relatively insensitive to the deleterious effects of heating and/or aging in the presence of air. The presence of the stabilizers also eliminates the phenomenon of the "migration" of the perfume oil caused by repeated vaporization and condensation within an enclosed space. In addition, the inclusion of the stated stabilizers, when judiciously used, tends to "round out" or "smooth out" the overall perception of the odor characteristics of the particular oils utilized, often increasing the aesthetic value of the fragrance composition when so used.

Description

This invention is concerned with air fresheners and more particularly with the stabilisation of such formulations .

Air fresheners or space deodorants have come into 5 increasing use in the household market in recent years.

Their sales and use have increased rapidly and represent a substantial market. Such products usually consist of liquid, aerosol, or more generally, a semi-solid composition comprising various oils and other components pack10 aged in a container provided with openings to expose.the fragrance composition to the atmosphere. The fragrance components volatilize into the atmosphere to mask or otherwise decrease the perception of malodor that may be present therein.

Almost invariably the freshener compositions are comprised of volatile materials that lend a distinct fragrance of their own to the atmospheric environment. While the fragrances preferred by consumers change from time to time they usually fall into categories such as those of floral scents, citrus scents, pine scents, and herbal scents and other less distinct groupings referred to as fantasies. All such scents impart their own distinct fragrance to the atmosphere and all rely upon a number of theoretical mutually operative mechanisms to lower the perceived strength of malodor.

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Since all such fragrances rely upon these effects, they are only effective to the extent that they volatilize efficiently to impart a significant amount of active material to the atmosphere to combat malodors present in their vicinity. While such compositions at the present state of the art are quite effective in producing a high or adequate level of active volatile material in the atmosphere when new and fresh, they usually rapidly lose their potency, or are so volatile that the active materials are completely evaporated within a short period of time, say within a few days when continuously exposed to the ambient atmosphere.

It is therefore of interest to produce compositions that retain their effectiveness over longer periods of| time whereby space deodorants may have an extended effective life and the resultant economic benefit will be | realized by the consumer.

In the past, efforts to solve this problem have resorted to compositions utilizing less volatile fragrances, or formulations wherein the fragrances tend to be relatively immobilized. In the first instance, the less volatile fragrances may be so non-volatile as to fail to produce an effective level of fragrance or active material in the ambient atmosphere. In the second instance, resort is often made to solid or semisolid gels or similar formulations which reduce the volatility of the active components by requiring that they migrate through the mass of the gel or semi-solid ? toward its atmospheric interface prior to volatilization, thereby increasing the active life of the composition. , Such solid or semi-solid compositions, however, are tedious to formulate, requiring mixing, heating, pouring - 4 into molds, or otherwise forming the gels and semi-solids, so that the active components are effectively volatile without being too tightly bound within the formulation such that their activity is unduly depressed. In the case of aqueous alginate and carrageenan based gels, the unsightly shrinkage over a period of time of the semisolids thus produced is, in practice, impossible to avoid.

We have now -found a new liquid air freshener formulation which in our tests has shown the following advantages 1. Reduction of the rate of volatilization of the active components of the odor counteractant composition. 2. Prevention of migration of the perfume oil, caused by repeated vaporization and condensation in an enclosed space to surfaces other than those to which the oil was applied. ; 3. Stabilization of the aesthetic qualities of the fragrance of the active composition by the reduction of the rate of its degradation due to heating, aging and intrinsic or extrinsic chemical reaction or instability. 4. Stabilization of the aesthetic quality by rounding or smoothing of perfume oils, when said stabilizers are judiciously applied by one skilled in the perfumery art.

These advantages can result in the formulation having a longer effective life.

The invention thus provides a liquid air freshener formulation comprising at least one volatile fragrance material and, as a stabilizer therefor, an alkylphenyl ether of a polyoxyethylene glycol in which the alkyl group may be saturated or unsaturated, the formulation being non-aqueous or containing less than 10% water by weight and containing at least 5% by weight of said 4 ΰ ii 3 3 - 5 volatile fragrance material! In general, the alkyl group of the ether used may have 6-20 carbon atoms and may be straight or branched, saturated or unsaturated, as for example in an alkenyl or alkynyl group. The polyether chain may for example have an average of 5 to 13 units of ethylene oxide. In particular, alkyl phenoxy polyethyl ethanols averaging from 9 to 12 moles ethylene oxide, and alkyl radicals ranging from 8 to 9 carbon atoms therein are preferred.

The addition of such alkyl phenoxy polyethoxy ethanols to air freshener quality formulations also appears to improve the olfactory quality of the formulation and to round out or to “smooth the fragrance to make it more pleasing to the person receiving the fragrance, providing the fragrance composition is judiciously chosen, preferably by one skilled in the art of perfumery. In some instances the result of the addition of said ethoxylates can result in an effect which might be termed dulling or as suppression of topnote resulting in a flatting effect. Judgement must be exercised in such a case, whether the benefits of 1, 2, and 3, above, outweigh the possible undesirable effect in 4 above. The case more often, however, is one of enhancing the aesthetic value of air freshener quality oil; making it perceived as less harsh or less chemical smelling.

* The addition of alkyl phenoxy polyethyl ethanols to the formulation has also shown, in our tests, a tendency to reduce the undesirable characteristics of fragrance oil formulations to evaporate and recondense in a closed space such as a package to form beads or droplets of pure fragrance oil. The evaporation4 6 ϋ 9 3 - 6 condensation phenomenon in the past has hindered the marketing of such formulations in other than semi-solid form or in pressurized containers and has prevented their being effectively marketed by the simple absorption of said fragrance oils onto any number of inexpensive absorbent substrates such as paper pads. Addition of the alkyl phenoxy polyethoxy ethanols can reduce this undesir able characteristic to the extent that the liquid formulation may be absorbed on any suitable porous material and be packaged in a closed container without the evaporation and recondensation of the fragrance oil to adjacent inner surfaces of the package.

Air freshener formulations generally comprise as an essential component, one or more fragrance oils; or in lieu of these, what could be considered as being more commonly practiced in the present state of the art of air freshener fragrance technology, man-made synthetic mixtures. These synthetics approximate essential oils in their olfactory impression and often consist of essential oil fraction, and chemical odorants of which there is no counterpart found in nature, and chemical odorants known to have odor counteractant activity. The substances function in an air freshener device of an evaporative action to distribute their fragrance and active materials into the surrounding air spaces. These essential oils are standard articles of commerce and are derived from a great number of plant and animal sources, and virtually all have their “synthetic counterparts as a result of advances in synthetic organic chemistry. Generally, many fragrance oils or synthetics are compounded together to produce the fragrance effects desired by the compounder.

The fragrance oils and synthetics, in turn, are compounded with additional components that service several functions; often the fragrance oils and synthetics themsel/es serve in these functions. Among these functions are so-called fixation of the fragrance to increase its permanence, solubilization of the oils, and volatilization control agents.

As indicated above, the addition of a quantity of alkyl phenoxy polyethoxy ethanol to the fragrance oil formulation can result in a stabilization of the fragrance oils whereby the effective life therefor is considerably extended. In this context, :life is taken to mean the extension of the fragrance oils ability to produce effective levels of fragrance in the surrounding environment over a period of time greater than is the case in the absence of these ethoxylates.

Also, again as indicated above, the recondensation of the fragrance oils on nearby surfaces, i.e. the package can be essentially eliminated, allowing the formulation to be prepared in a liquid form and absorbed on any porous material, such as blotting paper and the like thereby to produce a dry product. This effect can be thought of as a corollary to the extension of the life of the composition due to its depression of overall vapor pressure and the high affinity that alkyl phenoxy polyethoxy ethanols have for organic vapors in general.

Either or both of these effects are operative to prevent migration of the fragrance oil from the absorbent substrate to other areas where condensation of the oil is undesirable.

In the preferred formulations of the invention, fragrance oils, man-made synthetic mixtures, essential oil fractions and chemical odorants, and chemical odorants known to have counteractant activity generally received, in practice as, a finished composition are combined with alkyl phenoxy polyethoxy ethanols to produce the desired air freshener product. These materials may be in any standard formulation or variation thereof; the formulation, in this respect, is prepared to produce the desired fragrance or odor counteractant activity in accord ance with conventional practice.

Any number of fragrances are useful in the air freshener formulation. Some examples are: citronellol, hydroxy-citronellol, rhodinol, eugenol, geraniol, rose oil, heliotropine, peru balsam, ylang-ylang oil, isoeugenol, bergamot, coumarin, musk, and all or any of .the synthetic counterparts of the foregoing, and odorant chemicals of which there is no counterpart in nature.

These materials are generally used in combination to achieve the desired fragrance and odor counteractant effect.

Components to enhance or vary fragrances are multitudinous and are comprised of virtually all organic functional groups including alcohols, esters, ketones, aldehydes, acids, terpines, ethers and other materials of a highly complex nature, to name a few. Some of the foregoing materials function not only as odorants but to dual purposes such as solvents, viscosity controlling agents, etc.; while others used in trace amounts may serve as fragrance modifiers. All of the above may be included in the formulation of an odor counteractant compound in accordance with the desires of the formulator.

To this prepared and sometimes very complex composition of fragrances, enhancers and modifiers are generally added from 5% to 95% by weight of an alkylphenol ether of polyethylene glycol as stabilizer. In the preferred formulations the compounds of the class octylphenyl ethers of polyethylene glycol are used. Such compounds have the general formula: Those agents of the above structure wherein X is from 9 to 12 are especially preferred in the formulation.

The octylphenol ethers of polyethylene glycols are commercially available (Rohm and Haas, under the Trade Mark Triton) as a mixture of polyoxyethylene chains of lengths of 1 to 30 oxyethylene units. These are generally obtained as mixture of varying polyoxyethylene chain lengths distributed according to the Poisson distribution, and in practice the chain length can be reasonably well specified. Those agents having an average chain length from 9 to 12 moles of ethyleneoxide are especially preferred in the formulations of the invention.

The alkylphenol ethers of polyethylene glycol are often used, due to their surface-active properties, to render perfume oils (viz. volatile fragrance oils) soluble in, dispersed in, or otherwise integrated into aqueous media. The formulations of this invention, however, are non-aqueous or substantially non-aqueous (e.g. contain less than 5 or 10% by weight of water).

Most generally, the stabilized fragrance formulation is, in the context of this invention, absorbed in a porous matrix, (e.g. a spongy material or an absorbent 6 G 9 3 - 10 paper, such as blotting paper) which is then packaged in a sealed container for storage and subsequent distribution for retail sales. In use, the container is unsealed and opened to release the fragrance into the surrounding environment. The container may, for example be provided with openings to expose the formulation to the air and a cover adapted to prevent partially or completely the exposure of the formulation to the air.

We have found in our tests that the addition of alkyl phenoxy polyethoxy ethanol stabilizes the fragrance components so as to appreciably extend their useful life, i.e., prolong the time during which the formulation retains its ability to effectively provide the desired level of fragrance in its surroundings while being continuously or continually exposed to the ambient atmosphere; protects the aesthetic qualities of the fragrance of the active compound by reduction of the rate of its degradation due to heating, aging and intrinsic and extrinsic chemical reaction or instability; prevents or reduces migration of the perfume oil caused by repeated vaporization and condensation to surfaces other than those to which the oil was applied; and improves the aesthetic quality or “smoothing1' of the perfume oil.

One method of determining the life of the fragrance oil formulation absorbed as described in the foregoing, is to measure its weight as a function of time.

Such loss is due to evaporation of the various components to the surrounding atmosphere. In order to test the effectiveness of the formulations of the invention, four fragrance oil test compounds were prepared. Eight grams of each test fragrance oil formulation were absorbed into a 4 millimeter thick blotter paper which had a total of » ό u 9 3 - 11 80 sg. inches evaporative surface area. Second, eight gram samples each of the same 4 fragrance oil formulations were then mixed with 8 grams each of octylphenol polyethoxy ethanol (average 9-10 ethylene oxide groups) and the individual samples were absorbed on said blotter paper which was identical in size with those previously noted.

All blotter paper samples were then allowed to evaporate at controlled and identical conditions into the surrounding atmosphere and were reweighed periodically. The four test compositions of the fragrance oil formulations were as follows: FORMULA I Parts by Weight 225 Amylcinnamic Aldehyde 15 670 Venzyl Benzoate 3400 Citronellol 450 Diethylphthalate 1460 Hydroxyeitronello1 225 Indole 10% in Diethylphthalate 20 2420 Phenylethyl Alcohol 1150 Rhodinol 10000 6 G '3 3 Parts by Weight FORMULA 11 275 Aldehyde C-8 10% in Diethylphthalate 1850 Eugenol 600 Geraniol 470 Indole 10% in Diethylphthalate 730 Linalyl Acetate 2500 Methyl Anthranilate 3150 Petitgrain Oil 425 Phenylethyl Alcohol 10000 FORMULA III Parts by Weight 324 Acropal (Firmenich) 39 Bois De Rose Oil, Brazil 26 Heliotropine 114 Tincture Civet 3% in Alcohol 39-C 20 229 Iralia, Pure (Firmenich) 110 Peru Balsam, Decolorized, 10% in Alcohol 39-C 129 Violette AC (Ionine Alpha) 14 Ylang Oil II 25 15 Irophore (Firmenich) 10000 g ύ ο 3 3 FORMULA IV Parts by Weight 225 192 248 135 Amyl Salicylate Benzyl Salicylate Coumarin Isobutyl Salicylate Isoeugenol, Extra Misk Ambrette Violette AC (ionone Alpha) Ylang Oil II Bergamot 136 (Synthetic) 10000 Figs. 1, 2, 3 and 4 of the accompanying drawings present, respectively, plots of the natural logarithms (loge) of the sample weights as against time (days), for each of the sample formulations 1, 2, 3 and 4. In each figure the curves indicated by the Os present data for the fragrance oil-octylphenoxy polyethoxy ethanol formulations; while the curves indicated by the Xs present data for the fragrance oil formulation alone.

A review of each of the graphs clearly indicates that the invention formulations suffered considerably less weight loss over time as compared to the fragrance oil formulations alone.

In a second experiment to detect migration, the blotters were placed in (inner) cage-like containers open to the ambient air. These containers had a covering jacket which could be completely or partially removed to permit access to the ambient air, and in the experiment the jackets were sealed and then subjected to temperature 6 6 9 3 - 14 fluctuations which might be typical of those encountered in the course of distribution and sale of such a device.

The temperature variations were on the order of 50° (50°Fo 100 F). Many experiments of this nature were carried out not only with the above test compounds but with a large number of typical air freshener compounds. At the end of varying amounts of time (from 1 week to 9 months) the containers were opened and checked for migration or recondensation of the formulation on the inner surfaces of the container. No such migration or recondensation was noted in the case of those compositions which contained octylphenoxy polyethoxy ethanol. Thus, it appears that the addition of this material and its analogs to fragrance oil formulations modifies their vaporization-condensation properties by either lowering the total vapor pressure of the fragrance oil mixture and/or by modifying their recondensation behaviour. This may be explained by the stabilizer's high affinity for organic vapors, which prevents the recondensation of the fragrance oil on surrounding container surfaces.

In addition, the above test formulations and a large number of typical air freshener formulations were sealed in the above described devices and were subjected to temperatures which normally destroy much of the aesthetic quality of such fragrance oils. It was found with the above test mixtures and most commercial air freshener fragrance compounds that one week of a tempero ature of 140 F was sufficient, by sensory panel evaluation, to seriously impair the olfactory quality of the oils.

On the other hand, when the same oils and test compounds were mixed in a ratio of 1:1 (by weight) with octylphenol polyethoxy ethanol, there was generally reported by test u ϋ 3 3 - 15 panel members a dramatic reduction in the amount of degradation due to the heat encountered by the oils. The upper temperature limit in normal shipping practices of commercial articles is commonly considered to be 140°F; but even brief periods at this temperature in devices such as those in which there is a high ratio of air to oil would result in the degradation of the perfume oil and an attendant decrease in overall aesthetic value.

Similar experiments as the above were carried out at a constant temperature (1OO°F) with aging as a single variable. Over a period of nine months to a year at 100°F olfactory panels found distinct, and in some cases dramatic, differences between fragrance compositions protected by the ethoxylates of this invention compared to those to which no such protection was afforded.

These effects have been observed in a very large number of air freshener compounds and in great detail in the test compounds named above. The above test compounds were found to be easily degraded by heating and aging in the absence of the ethoxylate additives.

The mechanisms as to why ethoxylates of this series can produce what is essentially a chemical stabilization of the aesthetic qualities of the fragrance of the compositions through the reduction of the rate of degradation by heating and aging, and intrinsic chemical instability may be explained by the following hypothesis. The individual ingredients which comprise the fragrance formulation are sequestered by the alkyl phenoxy ethanol chain so as to separate the ingredients one from another, to thus prevent the interaction one with another, and to so bind them along the ethoxylate molecule such that they are resistant to the oxidative effects of the atmosphere contained within the device. This apparent chemical stabilizing of what appears to be fragrance oils in general was a completely unexpected and even startling outgrowth of experiments designed to prolong the effective life of air freshener devices.

It will be appreciated that containers of the formulations of the invention will normally be marketed in association with directions for their use as an air freshener . The directions will usually be printed, for example either onto the container itself or onto a package or wrapping for the container, or they may be printed on a leaflet packed with or attached to the container.

As will be seen from the above description, the invention is principally concerned with formulations containing just the two types of ingredient, the fragrance material and the stabilizer. Essentially aqueous compositions, i.e. those containing more than 10% by weight water, in which the alkylphenylether is included as an emulsifier rather than a stabilizer, are not included within the scope of the invention. Similarly excluded are compositions in which only a small quantity (i.e. less than 5% by weight) of fragrance material is present as an incidental ingredient.

Claims (17)

1. CLAIMS:1. A liquid air freshener formulation comprising at least one volatile fragrance material and, as a stabilizer therefor, an alkylphenyl ether of a polyoxyethylene glycol in which the alkyl group may be saturated or unsaturated, the formulation being non-aqueous or containing less than 10% water by weight and containing at least 5% by weight of said volatile fragrance material.

2. A formulation as claimed in claim 1 wherein the ether is present in an amount of 5 to 95% by weight of the whole formulation.

3. A formulation as claimed in claim 1 or claim 2 wherein the alkyl group contains 6-20 carbon atoms.

4. A formulation as claimed in claim 3 wherein the alkyl group contains 8 pr 9 carbon atoms.

5. A formulation as claimed in any one of the preceding claims wherein the polyoxyethylene chain contains an average of 5 to 13 ethylene oxide units.

6. A formulation as claimed in claim 5 wherein the polyoxyethylene chain contains an average of 9 to 12 ethylene oxide units.

7. A formulation as claimed in claim 1 or claim 2 wherein the ether is an octylphenyl ether of a polyethylene glycol containing an average of 9 to 12 ethylene oxide units.

8. A formulation as claimed in claim 7 and comprising a composition substantially as described herein for any one of Formulae I-IV mixed with the said polyoxyethylene glycol ether. 4 G G 'J. 3

9. A container containing a formulation as claimed in any one of the preceding claims.

10. A container containing a formulation as claimed in any one of claims 1 to 8 and being adapted to expose the formulation to air.

11. A container as claimed in claim 10. wherein the formulation is absorbed on a porous material.

12. A container as claimed in claim 11 wherein the porous material is absorbent paper.

13. A container as claimed in claim 11 wherein the porous material is a spongy material.

14. A container as claimed in any one of claims 10 to 13 which is provided with openings to expose the formul ation to the air and a cover adapted to prevent partially or completely the exposure of the formulation to the air.

15. A container as claimed in any one of claims 11 to 15 in association with directions for the use thereof as an air freshener.

16. A method of producing an air freshener formulation as claimed in any one of claims 1 to 8 which comprises the step of mixing the ether with the volatile fragrance material.

17. '. A method of producing a container as claimed in claim 11 which comprises the steps of absorbing the formulation on the porous material and then placing the porous material in the container.