GB2296190A - Gel fragrance composition - Google Patents

Abstract

A self supporting gel composition essentially comprises by weight 88 - 98.4% a fragrance material and 1.6 - 12% a dibenzylidene alditol gelling agent and can be used in air freshening systems.

Description

INPROVl9XE:NT8 IN OR RELATING TO ORGANIC COMPOSITIONS The present invention relates to fragrant compositions and, in particular, to a gel type fragrant composition and a method for preparing the composition.

Fragrant compositions are commonly used as air fresheners, and typically are provided in gel form. Such compositions would normally contain a gelling agent and a perfume, together with a solvent and other ingredients.

The use of a solvent and other ingredients together with a gelling agent can lead to elaborate manufacturing processes, increasing the cost of making the fragrant compositions. The resulting gel may have an unattractive opaque appearance, and would have to be concealed in a decorative container to give a marketable product. More fundamentally, the more components a fragrant composition contains, the greater the chance that the volatile components will be released at a non-uniform rate. If large amounts of volatile solvents are included, these will evaporate along with the perfume, causing shrinkage and deterioration of the gel structure. This effect, known as syneresis, leads to a reduction in the rate of release of perfume, and again renders the gel unattractive in appearance.

We have now found that it is possible to achieve a physically attractive clear gel type fragrant composition without the use of substantial amounts of solvent in a selfsupporting gel.

According to the present invention, there is provided a self-supporting gel composition essentially comprising 88-94% of a fragrance material and 1.6-12% of a dibenzylidene alditol gelling agent, all percentageS being by weight.

The fragrance material can be a mixture of perfume components and diluents including solvents. Preferably however, the fragrance material does not contain glycol ethers, more preferably less than 5% of solvent is present in the fragrance.

The invention allows large amounts of neat fragrance to be incorporated into the composition. Thus, in a preferred embodiment the fragrance is present in an amount 95% or more by weight.

Preferably the compositions are clear gel compositions.

The amount of gelling agent should not be more than the fragrance can take up to make a gel. Thus, the gelling agent is present in an amount 12% or less by weight. There is no advantage to be gained from using more gelling agent than is necessary to give an effective gel. Thus, preferably the gelling agent is present in an amount 4% or less by weight. On the other hand, there should be enough gelling agent present to form a stable gel. Ideally the gelling agent is present in an amount between 1.6% and 2.2% by weight, and particularly at 2% by weight. A novel preferred composition according to the nvention is one comprising 98% fragrance material and 2% gelling agent.

Further, the invention provides a method for preparing a self-supporting gel composition comprising heating the fragrance material with the gelling agent. This may be achieved by heating the fragrance material to a predetermined temperature, adding the gelling agent, reheating to maintain the temperature if necessary, and cooling.

The composition may be moulded into an attractive shape.

Thus, a preferred embodiment includes the further step of pouring the composition into a mould before cooling.

The predetermined temperature must be sufficient to produce an effective gel. Preferably this is between 700C and 1000C, though a temperature of between 800C and 900C will be sufficient for most fragrance materials.

The invention further provides a method for fragrancing rooms using the gel type fragrant composition. When emanation of fragrance is slow at room temperature, this may comprise elevating the temperature of the composition by placing it near a heat source. The heat source itself is suitably kept at a temperature between 400C and 600C.

The invention will be more fully understood from the following description.

The dibenzylidene alditols used as gelling agents are addition products of the relevant alditol with an optionally substituted benzaldehyde. As alditols are polyhydric alcohols, a number of regioisomers are possible. However, typically an alditol of formula (I):

will give a dibenzylidene derivative of formula (II):

When the alditol is sorbitol (n = 2), the unsubstituted dibenzylidene sorbitol (DBS) is commercially available, for example as GELL-ALL-D manufactured by New Japan Chemical Co., Ltd., and MILLITHIX 925 manufactured by Nilliken Chemical, a division of Milliken & Company.Substituted dibenzylidene sorbitols that have been previously reported include the following: p-chlorodibenzylidene sorbitol - ethyldibenzylidene sorbitol - di(m-chlorobenzylidene) sorbitol - di(m-fluorobenzylidene) sorbitol - di(p-methylbenzylidene) sorbitol As will be gathered from the names in the above list, the substitution may be on either one or both benzene rings.The latter are more readily available: di(p-methylbenzylidene) sorbitol is manufactured by Roquette Frères of Lestrem, France, and the synthesis of di(m-chlorobenzylidene) and di(m-fluorobenzylidene) sorbitols is given in US-A-5023354 (Salome et al . /Roquette Frees) and WO-A-92/19221 (The Procter & Gamble Company), the disclosure of which is incorporated herein by reference.

The alditol may be any of the other six-carbon alditols, in either the D- or the L- isomer form. It may also have four, five or seven or more carbon atoms. A general method for synthesizing substituted di(p-benzylidene) xylitols (n = 1) and the isomeric di(p-benzylidene) ribitols (n = 1) is given in JP-A-1-62377 (Kao Corp.) and US-A-4429140 (Murai et al./New Japan Chemical Co., Ltd.), the disclosure of which is also incorporated herein by reference.

The gelling agent is preferably a known optionally substituted dibenzylidene sorbitol, dibenzylidene xylitol or dibenzylidene ribitol. More preferably, it is an optionally substituted dibenzylidene sorbitol. The most readily available gelling agent is dibenzylidene sorbitol itself, though a di(methylbenzylidene) sorbitol can also be used.

The compositions according to the invention relate to moulded air freshener gels which are sold packaged in a suitable wrapper that is impermeable to fragrance. The wrapper is removed before the gel is used for fragrancing rooms, cars etc. The clear gels are physically attractive and may be displayed or placed in a suitable container.

Alternatively, the fragrance may be of a type which only evaporates effectively at elevated temperature. The provision of a fragrance-impermeable wrapper is then not so crucial. The gel is placed by a suitable heat source and heated at around 400C to 600C whenever release of fragrance is desired.

By self-supporting gel is meant a gel that is of sufficient rigidity that it is firm and is not capable of flowing and maintains its structure. Such a gel is one that can be used as a stick without support means, ie able to stand alone.

The following examples illustrate compositions according to the present invention, their method of making, and their use.

EXAMPLE 1 The formulation of Table 1 was prepared using the fragrance LN49525 manufactured by Bush Boake Allen Ltd. (BBA) of London, England, and dibenzylidene sorbitol manufactured by Roquette Frdres of Lestrem, France.

TABLE 1

Fragrance LN49525 98% w/w Dibenzylidene 2% w/w sorbitol a) The fragrance was initially heated to 800C and the dibenzylidene sorbitol (DBS) was then added. This appeared to produce an endothermic reaction, and the temperature fell by between 80C and 120C. No gelling occurred at this lower temperature, even after five minutes of stirring. However, reheating to between 780C and 800C caused a gel to form.

b) The fragrance was initially heated to 900C and the DBS was then added. The DBS solubilized readily and on cooling set to a firm clear gel.

EXAMPLE8 2 to 4 Further formulations were prepared using 2% w/w of DBS, together with 98% w/w of each of the fragrances given in Table 2 and supplied by BBA and Robertet S.A. of Grasse, France.

TABLE 2

Example 2 LN47490 ex BBA Example 3 LN47488 ex BBA Example 4 K/23899 ex Robertet In each case the fragrance was initially heated to 800C, and the DBS was then added. A temperature drop was usually observed on adding the DBS, but reheating to 800C caused a gel to form. The temperature drops observed and the time taken for the DBS to dissolve to make a gel were as indicated in Table 3.

TABLE 3

Example Temperature Time to drop dissolve 2 40C 310 s 3 20C 520 s 4 20C 390 s The gels were placed in containers suitable for emanation.

The weight loss in grams was recorded daily and a graphical representation was drawn to depict the percentage weight loss of perfume from each gel, as shown in Fig. 1.

EXAMPLES S TO 7 AND COMPARATIVE EXAMPLES A TO C Formulations using different proportions of the fragrance K/23899 ex Robertet were prepared as in Examples 2 to 4 according to Table 4.

TABLE 4

Example Fragrance DBS 5 98.0% w/w 2.0% w/w 6 98.2% w/w 1.8% w/w 7 98.4% w/w 1.6% w/w A 98.6% w/w 1.4% w/w (comparative) B 98.8% w/w 1.2% w/w (comparative) C 99.0$ w/w 1.0% w/w (comparative) With Examples 5 to 7, a firm dry gel was obtained.

However, when less than 1.6% w/w of DBS was used as in comparative Examples A to C, no useful gel was obtained.

Substantially more than 2% w/w of DBS could also be used, but such a gel would offer no advantage over those using around 2%.

The three successful gels were placed in containers suitable for emanation. The weight loss in grams was recorded daily and a graphical representation was drawn to depict the percentage weight loss of perfume from each gel, as shown in Fig. 2.

EXAMPLES 8 TO 13 98.4 g of fragrance were placed in a beaker and 1.6 g of DBS were added. The fragrance and DBS were then mixed with a Sonicatorm ultrasonic liquid processor manufactured by Heat Systems Incorporated of Farmingdale, USA, and the mixture was mixed until it was clear. The time and temperature at which this occurred were recorded, and the gel was then poured into a mould and allowed to set. The results obtained with different fragrances, supplied by Robertet S.A., V. Mane Fils S.A. of Grasse, France, Firmenich S.A. of Geneva, Switzerland, and BBA, were as indicated in Table 5.

TABLE 5

Exampl Fragrance Temperatu Time e re 8 Parair Lite K/25243 80.00C 2 min 40 ex Robertet s 9 Alpha A Lite K/25242 85.20C 4 min 30 ex Robertet s 10 Lavender conc. 97.60C 3 min 30 K/25541 s ex Robertet 11 Fancy dress fruit 90.20C 3 min 30 EAR 65169 5 ex V. Mane Fils S.A.

12 Mountain mint 433192 91.00C 4 min 30 ex Firmenich s 13 Apple LM4330 70.60C 3 min 20 ex BBA 8 Thus, with suitable choice of fragrance, a gel can be obtained at as low as 700cor as high as 1000C. Factors influencing this include the solvent/surfactant content and the polarity of the fragrance. For example, the fragrances used in Examples 8 and 9 were specifically designed to be of sufficient volatility. The basic formulae are shown in Table 6.

TABLE 6

Example 8 9 Parair Lite Alpha A Lite K/25243 K/25242 Benzyl acetate 14% w/w 14% wlw Geraniol 10% w/w Lineal 1 acetate 10% w/w - Methyl ionone 10% w/w 18% w/w Phenylethyl 8% w/w alcohol Phenylethyl 8% w/w acetate Dimethyl benzyl 8% w/w carbinyl acetate Ethyl diglycol 32% w w 25% w/w Bergamot - 14% w/w synthetic Methyl - 14% w/w dihydrojasmonate Linalol - 10% w/w Dihydromyrcenol - 5% w/w EXAMPLES 14 TO 19 AND COMPARATIVE EXAMPLE D The fragrance Parair Lite K/25243 and DBS components were mixed with a Sonicatorn ultrasonic liquid processor until the mixture was clear. The time and temperature at which this occurred was recorded and the gel allowed to set in a mould.

The results are shown in Table 7.

TABLE 7

Example Fragrant DB8 Temperatu Time e re 14 98% w/w 2% w/w 960C 2 min 8 s 15 96% w/w 4% w/w 1000C 1 min 56 s 16 94% w/w 6% w/w 1020C 2 min 13 s 17 92% w/w 8% w/w > 1030C 1 min 55 s 18 90% w/w 10% > 1030C 3 min 13 s w/w 19 888 w/w 12% @ > 1030C 4 min 38 s w/w D 86% w/w 14% not not (comparativ w/w applicabl applicable e) e Thus gels can be formed with a percentage of DBS up to 12% w/w, allowing 88% w/w or more of fragrance to be used.

Increasing this percentage further causes the mixture to solidify.

EXAMPLES 20 AND 21 DBS gels were made as Examples 8 and 9, using Parair Lite K/25243 for Example 20 and Alpha A Lite K/25242 for Example 21.

6 g fill of each gel was placed in a small mould and a resistance heater running at a temperature of 500c was placed underneath the centre of the mould, leaving the front emanating surface free. The percentage weight loss from each gel is shown in Fig 3.

Comparison of Examples 20 and 21 in Fig. 3 with Examples 2, 3 and 4 displayed in Fig. 2 shows that the addition of heat vastly increases the fragrance emanation from the DBS system.

COMPARATIVE EXAMPLE E In an attempt to produce a gel without using heat, fragrance and powder were mixed in a rotary powder mixer, using the method disclosed in JP-A-55-15452 (EC Kagaku Kogyo KK). It was found that up to 45 g of fragrance could be absorbed onto 100 g of powdered dibenzylidene sorbitol so as to give a dry powder. When more fragrance was used, a two-phase mixture of powder and surplus fragrance resulted. However, it did not prove possible to produce a gel by this method.

The experimental work given above has primarily been concerned with the production of moulded air freshener gels which are sold packaged in a suitable wrapper that is impermeable to the fragrance. The wrapper is removed before the gel is used for fragrancing rooms, cars and the like. The clear gels are physically attractive and may be displayed or placed in a suitable container.

Claims (20)

CLAIMS:

1. A self supporting gel composition essentially comprising 88 - 98.4% of a fragrance material and 1.6 - 12% of a dibenzylidene alditol gelling agent, all percentages being by weight of the composition.

2. A gel composition according to Claim 1 in which the gel is clear.

3. A composition as claimed in claim 1 or 2 in which the gelling agent is present in an amount 4% or less by weight of the total composition.

4. A composition as claimed in any one of the preceding claims in which the gelling agent is present in an amount between 1.6% and 2.2% by weight of the total composition.

5. A composition as claimed in any one of the preceding claims in which the gelling agent is present in an amount of 2% by weight of the total composition.

6. A composition as claimed in any one of the preceding claims in which the gelling agent is an optionally substituted dibenzylidene sorbitol, dibenzylidene xylitol or dibenzylidene ribitol.

7. A composition as claimed in claim 6 in which the gelling agent is an optionally substituted dibenzylidene sorbitol.

8. A composition as claimed in claim 7 in which the gelling agent is dibenzylidene sorbitol or a di(methylbenzylidene sorbitol).

9. A method for preparing a gel composition according to any one of the preceding claims comprising heating the fragrance material with the gelling agent.

10. A method as claimed in claim 9 comprising the steps of heating the fragrance material to an elevated tem-perature, adding the gelling agent, reheating to maintain the temperature if necessary, and cooling.

11. A method as claimed in claim 10 including the further step of pouring the composition into a mould before cooling.

12. A method as claimed in claim 10 or claim 11 in which the elevated temperature is between 700C and 1000C.

13. A method as claimed in claim 12 in which the elevated temperature is between 800C and 900C.

14. A method for fragrancing rooms using the gel composition of any one of claims 1 to 8.

15. A method for fragrancing rooms using a gel composition prepared by the method of any one of claims 9 to 12.

16. A method as claimed in claim 14 or claim 15, comprising elevating the temperature of the gel type fragrant composition by placing it near a heat source.

17. A method as claimed in claim 16, in which the temperature of the heat source is between 400C and 600C.

18. A gel composition as claimed in claim 1 or claim 2, substantially as described herein with reference to Examples 1 to 21.

19. A method for preparing a gel composition as claimed in claim 8, substantially as described herein with reference to Examples 1 to 21.

20. A method for fragrancing rooms with a gel composition, substantially as described herein with reference to in Examples 22 and 23.