EP0536444A1

EP0536444A1 - Stable concentrated perfume emulsion

Info

Publication number: EP0536444A1
Application number: EP91202607A
Authority: EP
Inventors: Paulus Antonius Augustinus Hoefte
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1991-10-07
Filing date: 1991-10-07
Publication date: 1993-04-14
Also published as: CA2080108A1

Abstract

The present invention relates to stable concentrated perfume emulsions and their use as additives to liquid fabric treatment compositions. The concentrated perfume emulsion comprises up to 24% perfume and at least 5% of an emulsifying compound. Preferred emulsifying compounds are ditallowimidazolines or ditallowimidazoline esters and optionally quaternary ammonium salts.

Description

Technical Field

The present invention relates to stable concentrated perfume emulsions. Particularly it relates to such stable concentrated perfume emulsions which are useful as additives to liquid fabric treatment compositions.

Background of the Invention

Fabric softening compositions have found wide acceptance with consumers for virtually all fabrics and washing circumstances. There are two ways most widely used for softening treatment of fabrics. One being the washing of fabrics using a "softening through the wash" detergent. The other way is to apply a liquid softening composition to one or several rinse cycles after the cleaning of the fabrics. This latter way of softening is particularly useful when the softening composition or its additives display limited compatibility with the detergents used during the wash. Regardless which softening treatment of fabrics is used, preferred additives to softening compositions are perfumes. There are several drawbacks if the fabric softener composition is supplied to the consumer already containing a perfume. A particular perfume scent may not be appealing to one consumer but have a most appealing smell to another consumer. Also the amount of perfume contained in a fabric softener may not coincide with the specific consumer desire regarding the strength of scent.
Therefore, supplying a fabric softener composition and a perfume composition separately meet a so far unsatisfied consumer demand. More generally separating the scenting from the other functions of fabric treatment compositions allows the consumer to decide which perfume scent and which perfume amount to use.
In a technical aspect the separation allows to formulate fabric treatment compositions containing ingredients which have limited tolerance or which are even destructive towards perfumes upon longer term storage. On the other hand, concentrated perfume emulsions, which are a subject of the present invention, may be formulated utilizing perfume compounds which so far have not found wide spread utilization for reasons of compatibility, stability or commercial reasons.
It will be appreciated by those skilled in the art of formulating liquid fabric treatment compositions that the apparent way of utilizing pure perfume as an additive to unperfumed compositions is not feasible since perfume cannot be emulsified by the consumer in usual liquid fabric treatment compositions without special efforts. Also the use of pure perfume directly in the wash or rinse is not economical since most of the fragnance would be lost by being washed away or evaporated. On top the measuring of the minute amounts of perfume required, would add undesirable complexity for the consumer if it was supplied as a pure perfume.
Therefore, applicants have developed concentrated perfume emulsions and a method to use such concentrated perfume emulsions which are solving the problems of perfume emulsification and stability, satisfying the consumer demand for simplicity, flexibility of the amount and of the scent of perfumes and which allow the use of compounds in concentrated perfume emulsions which may ordinarily display storage problems when being combined in a single product. These and other advantages will become more apparent in the detailed description of the invention.

Background art

Due to the novelty of the technology of concentrated perfume emulsion as additives to fabric treatment compositions the background art relating to this field is limited. The closest prior art obviously comes from the neighboring field of liquid softening compositions. However, as will become apparent this neighboring field does not concern itself much with the problems associated with providing or using concentrated perfume emulsions.
In European Patent Application EP-A- 397 296 perfume particles are disclosed which are incorporated in a polywax and then coated in a fryable coating. The solid perfume particles contain up to 70% perfume and are useful in detergent or softening compositions since the protective coating eliminates compatibility problems.
European Patent Application EP-A- 392 607 also discloses fabric treatment compositions comprising perfume. The perfume is provided in a solid cyclodextrin complex for protection and compatibility with fabric softening compositions.
Finally, European Patent Application EP-A- 199 382 describe liquid fabric softeners and methods for their use during the rinse cycle of home laundry operations. The liquid fabric softeners disclosed in this patent contain up to 2% of perfume.

Summary of the invention

The present invention relates to stable concentrated perfume emulsions and their use as perfume additive to fabric treatment compositions which are essentially perfume free. The present invention is based on the discovery of the stabilization effect of certain compounds in a particular pH range relative to high perfume concentrations and their ability to blend with fabric treatment compositions. Therefore, in its product aspect the present invention discloses a pourable, stable, concentrated perfume emulsion comprising between 2% and 24% by weight of the emulsion of perfume, a miniumum of 5% by weight of emulsifying compound and being adjusted to have a pH-10% in the range from 2.9 to 4.0 and a viscosity in the range from 0.2 to less than 2.0 Pa.s. The preferred emulsifying compounds are ditallowimidazolines or ditallowimidazoline esters, which represent 55% to 100% by weight of the amount of emulsifying compound. The concentrated perfume emulsions further comprise quaternary ammonium salts as emulsifying compound at 0% to 45% by weight of the emulsifying compound, but usually not exceeding 5% by weight of the emulsion. If quaternary ammonium salts are present the pH-10% range is from 3.4 to 4.0.
In a usage aspect of the present invention the use of concentrated perfume emulsions as a fabric treatment composition additive is claimed.
All percentages quoted hereinafter are by weight of the concentrated perfume emulsion unless otherwise specified.

Detailed description of the invention.

Perfume

One essential compound of the invention is perfume. As a compound in the present invention the word perfume encompasses individual perfume components and compositions of perfume components. Selection of any perfume is based solely on aesthetical considerations.
Perfume, in the sense of perfume components or compositions of perfume components, can be any odorifirous materials or any materials which act as a malodour counteragent. The perfume will most often be liquid at ambient temperatures, but also can be liquified solid such as the various camphoraceous perfumes known in the art. The perfume can be relatively simple in composition or can comprise highly sophisticated, compact mixtures of natural or synthetic chemical components, all chosen to provide any desired odour.
Useful perfumes are those odorous materials that deposit on fabrics during the laundry process and are detectable by people with normal olfactory sensitivity. Many of the perfume ingredients along with their odor corrector and their physical and chemical properties are given in "Perfume and Flavor chemicals (aroma chemicals)", Stephen Arctender, Vols. I and II, Aurthor, Montclair, H.J. and the Merck Index, 8th Edition, Merck & Co., Inc. Rahway, N.J. Perfume components and compositions can also be found in the art, e.g. US Patent Nos. 4,145,184, 4,152,272, 4,209,417 or 4,515,705.
A wide variety of chemicals are known for perfume use including materials such as aldehydes, ketones, esters and the like. More commonly, naturally occurring plant and animal oils and exudates comprising complex mixtures of various chemical components are known for use as perfume, and such materials can be used herein. Typical perfumes can comprise e.g. woody/earthy bases containing exotic materials such as sandalwood oil, civet and patchouli oil. The perfume also can be of a light floral fragrance e.g. rose or violet extract. Further the perfume can be formulated to provide desirable fruity odours e.g. lime, limon or orange.
Particular examples of useful perfume components and compositions are anetole, benzaldehyde, benzyl acetate, benzyl alcohol, benzyl formate, iso-bornyl acetate, camphene, cis-citral (neral), citronellal, citronellol, citronellyl acetate, paracymene, decanal, dihydrolinalool, dihydromyrcenol, dimethyl phenyl carbinol, eucalyptol, geranial, geraniol, geranyl acetate, geranyl nitrile, cis-3-hexenyl acetate, hydroxycitronellal, d-limonene, linalool, linalool oxide, linalyl acetate, linalyl propionate, methyl anthranilate, alpha-methyl ionone, methyl nonyl acetaldehyde, methyl phenyl carbinyl acetate, laevo-menthyl acetate, menthone, iso-menthone, myrcene, myrcenyl acetate, myrcenol, nerol, neryl acetate, nonyl acetate, phenyl ethyl alcohol, alpha-pinene, beta-pinene, gamma-terpinene, alpha-terpineol, beta-terpineol, terpinyl acetate, vertenex (para-tertiary-butyl cyclohexyl acetate), amyl cinnamic aldehyde, iso-amyl salicylate, beta-caryophyllene, cedrene, cinnamic alcohol, couramin, dimethyl benzyl carbinyl acetate, ethyl vanillin, eugenol, iso-eugenol, flor acetate, heliotrophine, 3-cis-hexenyl salicylate, hexyl salicylate, lilial (para-tertiarybutyl-alpha-methyl hydrocinnamic aldehyde), gamma-methyl ionone, nerolidol, patchouli alcohol, phenyl hexanol, beta-selinene, trichloromethyl phenyl carbinyl acetate, triethyl citrate, vanillin, veratraldehyde, alpha-cedrene, beta-cedrene, C15H24sesquiterpenes, benzophenone, benzyl salicylate, ethylene brassylate, galaxolide (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8,-hexamethyl-cyclo-penta-gamma-2-benzopyran), hexyl cinnamic aldehyde, lyral (4-(4-hydroxy-4-methyl pentyl)-3-cyclohexene-10-carboxaldehyde), methyl cedrylone, methyl dihydro jasmonate, methyl-beta-naphthyl ketone, musk ambrette, musk idanone, musk ketone, musk tibetine, musk xylol, aurantiol and phenylethyl phenyl acetate.
The perfume compound of the invention is included in the emulsion from 2% to 24%, preferably from 4% to 20%, most preferably from 4% to 10%. The most appropriate amount of perfume will easily be identified by knowing the dillution and the desired final amount in the fabric treatment composition.

Emulsifying compound

The other essential compound of the present invention is the emulsifing compound. The emulsifying compound is present at a minimum amount of 5%, preferably at an amount from 6% to 15%. The preferred emulsifying compound is ditallowimidazoline, ditallowimidazoline ester or mixtures thereof, which represent 55% to 100% by weight of the amount of emulsifying compound. Ditallowimidazoline or ditallowimidazoline ester can be described by the general formula :

wherein n is 2 or 3, preferably 2;
R₁ and R₂ are, independently, a C8-C30 alkyl or alkenyl, preferably C12-C20 alkyl, more preferably C15-C18 alkyl, or mixtures of such alkyl radicals. Examples of such mixtures are the alkyl radicals obtained from coconut oil, "soft" (non-hardened) tallow and hardened tallow;
Q is CH₂ or N, preferably N;
X is

wherein T is O or NR₅, R₅ being H or C1-C4 alkyl, preferably H;
R₄ is a divalent C1-C3 alkylene group or (C₂H₄O)m, wherein m is an integer of from 1 to 8;
or X is R₄.
Most preferred softening agents according to the above formula are ditallowimidazolines of the following formula:

or ditallowimidazoline esters of the following formulas :

wherein R₆, R₇ are tallow groups.
Even though ditallowimidazoline and ditallowimidazoline esters or mixtures thereof are equally preferred for technical reasons it is most preferred to have ditallowimidazoline esters or mixtures containing a majority of ditallowimidazoline esters, since ditallowimidazoline esters are known for their environmental compatibility.
If the emulsifying compound contains other materials than ditallowimidazoline, ditallowimidazoline ester or mixtures thereof, then it further comprises quaternary ammonium salts. Quaternary ammonium salts are present in an amount of up to 5%, preferably they are present from 1% to 4% of the composition. In accordance with the amount of ditallowimidazoline, ditallowimidazoline ester or mixtures thereof , quaternary ammonium salts can provide 0% to 45% by weight of the emulsifying compound.
Quaternary ammonium salts are well known in the art of fabric softening and can be described by the general formula : R₁R₂R₃R₄-N⁺X⁻. Any of the well-known substitution groups R1, R2, R3, R4 disclosed in the prior art can be used in the present invention. Most imminent examples of the prior art are EP-A- 397 296, EP-A- 392 607 or EP-A- 199 382, supra. The most preferred quaternary ammonium salts are ditallowdimethylammoniumchlorides (DTDMAC) and quaternary ester ammonium compounds.
X⁻ in above general formula represents any suitable anion, preferably alkali-metal anions or methyl sulfate anions.
The emulsifying compounds described herein above are suitable provided they are present in the concentrated perfume emulsion in their protonated or quaternized form; a suitable mean to protonate or quaternize these compounds is described for instance in EP 199 383.

Essential characteristics of the emulsion

To be phase stable over an extended period the concentrated perfume emulsion further must satisfy the criterium of having a pH-10% from 2.9 to 4.0, preferably from 3.0 to 3.6. If the emulsifying compound also contains quaternary ammonium salts, the pH-10% range is from 3.4 to 4.0, preferably from 3.4 to 3.6. The pH-10% can be adjusted with hydrochloric acid or any other suitable acid.
Another characteristic of the concentrated perfume emulsion is a viscosity in the range from 0.2 kg/m/sec to less than 2.0 Pa.s. Viscosity values below 2.0 Pa.s, preferably below 1.0 Pa.s, most preferably below 0.5 Pa.s ensure good pourability of the concentrated perfume emulsion. On the other hand very low viscosity is also undesirable for phase stability of the concentrated perfume emulsion as well as for consumer appeal reasons. Viscosity values from 0.2 Pa.s are useful. Adjusting the viscosity to the desired value between 0.2 Pa.s and 2.0 Pa.s can be accomplished by adding commercially available, innert viscosity enhancers like for example Lutensol (trademark).

Other optional ingredients

A variety of optional ingredients can be comprised in the concentrated perfume emulsion to include additional technical or aesthetical benefits. Among these are emulsion stabilizers, viscosity stabilizers, blending aids, dyes, pH-buffers, bactericites and any other compounds which are common in fabric treatment compositions and compatible to the concentrated perfume emulsion. The total quantity of optional ingredients or mixtures thereof usually will not exceed 10%.

Use of the concentrated perfume emulsion

The use of the concentrated perfume emulsion as an additive during the home fabric treatment is also part of the present invention. The amount of concentrated perfume emulsion is usually mixed with an essentially unperfumed, liquid fabric treatment composition which then can be used by the consumer. The essentially unperfumed fabric treatment composition can be any kind of liquid fabric treatment composition which allows homogeneous mixing of the concentrated perfume emulsion. Most preferred is the use of the concentrated perfume emulsion as additive to essentially unscented, liquid fabric softening compositions or liquid fabric softening concentrate compositions.
The amount of concentrated perfume emulsion to be used as an additive to fabric treatment compositions is solely dependent on aesthetic desires of the consumer. However, it has been found that a preferred range of the ratio of concentrated perfume emulsion to fabric treatment composition can be defined to accomplish usual perfume concentrations in fabric treatment compositions. Therefore, the preferred range of concentrated perfume emulsion to fabric treatment composition is from 0.5:100 to 50:100, most preferably from 3:100 to 20:100.
As indicated above the fabric treatment composition to which the concentrated perfume emulsion is added, is essentially unperfumed. Essentially unperfumed or essentially unscented does describe that the added perfume amount in the composition is below the detection level for people with normal olfactory sensitivity. For practical purposes and many perfume compositions this detection level is around a concentration of 0.01% of the fabric treatment composition. However, this does not apply to masking perfumes which are often required to overcome undesirable odours of fabric treatment composition ingredients. Even essentially unperfumed fabric treatment compositions therefore may contain a certain added perfume amount to mask malodour of the fabric treatment composition however without providing the aesthetical benefit of a scented fabric treatment composition.
To be useful as a fabric treatment composition additive, viscosity values of the concentrated perfume emulsion of clearly less than 2 Pa.s are required to allow easy pouring and mixing of the concentrated perfume emulsion with the fabric treatment composition.
Fabric treatment compositions as such are well-known in the art and do not need particular explanations. However, since the concentrated perfume emulsion is designed as an additive to such fabric treatment compositions an essential criterium is the compatibility of the fabric treatment composition with the concentrated perfume emulsion.
The preferred liquid fabric softening compositions and the liquid concentrated fabric softening compositions are also well-known in the art. Again the essential criterium for their selection is the compatibility with the concentrated perfume emulsion. Some of the preferred compounds for these liquid fabric softening compositions and concentrated fabric softening compositions are : softening clays, softening ammonium compounds including cationic softening ammonium compounds, softening enzymes, softening enhancers, like e.g. flocculating agents, or softening siloxanes which are all well-known in the art. Most preferred are such fabric softening composition compounds which are disclosed in EP-A-199382, EP-A-392607 or EP-A-397296 or which are referred to in the examples.

Measurement Methods

Phase stability :

To evaluate the phase stability characteristic of the concentrated perfume emulsion the following procedure was used :

1. Storage of the concentrated perfume emulsion for 8 weeks at room temperature (about 20°C) in closed glass containers.
2. Visual inspection after 1 day, 1 week, 2 weeks, 1 month and 3 months storage for perfume droplets, phase seperation, precipitation or coagulation in the emulsion.
3. Grading of results : if no visible change was detected the result was graded as "stable", otherwise it was graded "unstable".

pH :

To measure the pH value of the concentrated perfume emulsion it was diluted with 9 parts distilled water to 1 part concentrated perfume emulsion. The pH value of this dilute emulsion is designated as pH-10% throughout the specification.

Viscosity :

The viscosity was measured with a commercial Brookfield Viscometer type LV (Trademark) using the spindel No. 2 at room temperature and a shear rate of 60 rounds per minute.

EXAMPLES

The following examples illustrate preferred executions of this invention, and facilitate its understanding. Abbreviations for individual ingredients in the examples have the following meaning :

DTI/E is ditallowimidazoline or ditallowimidazoline esters as disclosed above.
DTDMAC is ditallowdimethylammoniumchloride
GMS is glycerolmonostearate
TAMET is tallowamine ethoxylate
PEG is polyethylene glycol
PDMS is polydimethylsiloxane

EXAMPLE I

Composition IX and X of Table I provide examples of the present invention while the other compositions of Table I allow a comparison of each of the individual components of composition IX. Compositions I, II, III, IV, V, VI, VII and VIII are not providing phase stability. From composition X, it can be derived that DTI/E is the critical compound to phase stability .

EXAMPLE II

Compositions I, II, III, IV, V , VI and VII of Table II provide indication of the importance of the pH-10% value.
At pH-10%=2.5 even the addition of thickeners cannot provide the required phase stability. The measured viscosity of compositions III and IV of Table II was 0.5 and 0.75 Pa.s respectively but still no stabilization was observed. Only at viscosity values outside the useful level as in composition V and VI of Table II, phase stable compositions can be formulated without observing the required pH-10%. Further examples differentiating compositions containing quaternary ammonium salts along a range of pH-10% values are examplified in Table II as compositions VIII to X.

EXAMPLE III

Table III provides comparisons of compositions I to X . Compositions I to IX do not comprize the required amount of emulsifying compound. Even at a viscosity of 9.9 Pa.s and 10% DTDMAC as in composition VIII phase stability cannot be achieved but is provided by composition X with less emulsifying compound. It can also be seen that ammonium compounds like DTDMAC alone are not capable of providing a stabilizing effect.

EXAMPLE IV

The following concentrated perfume emulsion is prepared according to the invention.

Perfume 7.5 %

DTI/E 3.62 %

DTDMAC 2.622 %

TAMET 0.213 %

GMS 0.853 %

PDMS 0.15 %

PEG 0.30 %

HCL 0.235 %

Myacide 0.01 %

Dye 0.048 %

Water balance
The composition is evaluated for phase stability, pH-10 % and viscosity confirming that it meets the criteria of the invention.
Independently the following fabric softening composition A* and concentrated fabric softening composition B* without perfume are prepared :

Composition :

	A*	B*
Softening active amines	7.047%	21.14%
PDMS	0.147%	0.44%
PEG	0.387%	1.16%
CaCl	0.067%	0.1 %
HCl	0.267%	0.8 %
Water and minors	balance	balance

To evaluate usage of the concentrated perfume emulsion it is added according to the following table to prepare compositions A and B.

Composition	A	B
Concentrated perfume emulsion of example III	100 g	100 g
Composition A*	900 g	-
Composition B*	-	300 g
Water	-	600 g
Total amount	1000 g	1000 g
Total perfume concentration	0.75 %	0.75 %

The concentrated perfume emulsion is added first into a beaker and the other ingredients are poured on top. No further agitation is necessary showing that the concentrated perfume emulsion easily blends with fabric treatment compositions.
Using the resulting compositions A or B as usual in home laundring provides the desired perfume level on fabrics.

Claims

A pourable, stable concentrated perfume emulsion comprising
- from 2% to 24% by weight of the emulsion of perfume and

- from 5% by weight of the emulsion of emulsifying compound in which
- 55% to 100% by weight of said emulsifying compound is ditallowimidazoline or ditallowimidazoline ester or mixtures thereof and

- 0% to 45% by weight of said emulsifying compound is a quaternary ammonium salt

and said concentrated perfume emulsion being adjusted to a pH-10% from 2.90 to 4.00 or to a pH-10% from 3.40 to 4.00 if quaternary ammonium salts are present,
and being adjusted to a viscosity from 0.2 to less than 2.0 Pa.s.
A concentrated perfume emulsion according to claim 1 characterized in that said perfume is present from 4% to 20% by weight of the emulsion.
A concentrated perfume emulsion according to any of the previous claims characterized in that said perfume is present from 4% to 10% by weight of the emulsion.
A concentrated perfume emulsion according to any of the previous claims characterized in that the emulsifying compound is present at an amount from 6% to 15% by weight of the emulsion.
A concentrated perfume emulsion according to any of the previous claims characterized in that the pH-10% is from 3.00 to 3.60, or from 3.40 to 3.60 if quaternary ammonium salts are present.
A concentrated perfume emulsion according to any of the previous claims characterized in that the viscosity is from 0.2 to 1.0 Pa.s preferably 0.2 to 0.5 Pa.s.
A concentrated perfume emulsion according to any of the previous claims characterized in that the quaternary ammonium salt is selected from the group of ditallow-dimethylammoniumchlorides.
A concentrated perfume emulsion according to any of the claims 1 to 6 characterized in that the emulsifying compound is entirely ditallowimidazoline or ditallowimidazoline ester or mixtures thereof.
A concentrated perfume emulsion according to any of the previous claims characterized in that it further comprises a dye or mixture of dyes.
Usage of the concentrated perfume emulsion of any of the previous claims as a perfume additive to fabric treatment compositions characterized in that said fabric treatment compositions are essentially free of perfume.
Usage according to claim 8 characterized in that the ratio of said concentrated perfume emulsion to said fabric treatment composition ranges from 0.5:100 to 50:100.
Usage according to claim 8 characterized in that the ratio of said concentrated perfume emulsion to said fabric treatment composition ranges from 3:100 to 20:100.