WO1999017717A2

WO1999017717A2 - Liquid compositions containing ethylcellulose and terpenoid compounds

Info

Publication number: WO1999017717A2
Application number: PCT/US1998/021101
Authority: WO
Inventors: Olivia Cuddihy; Ian J. Barlow
Original assignee: S. C. Johnson & Son, Inc.
Priority date: 1997-10-08
Filing date: 1998-10-07
Publication date: 1999-04-15
Also published as: ZA989196B; WO1999017717A3; GB9721373D0; AU1186299A; AR015177A1

Abstract

Liquid compositions containing a viscosity increasing amount of ethylcellulose, preferably 1 to 10 %, which has been dissolved in a liquid comprising a solubilizing proportion of a terpenol material, have a viscosity at 25 °C greater than the composition in the absence of ethylcellulose.

Description

IMPROVEMENT IN LIQUID COMPOSITIONS

TECHNICAL FIELD The present invention relates to clear solutions of certain organic liquids containing additives to increase viscosity. BACKGROUND ART

For various purposes it is desirable to be able to supply clear liquid compositions of increased viscosity. Thus, there is a need to provide certain liquid products containing more than minor amounts, e.g., more than 10%, of hydrocarbons with increased viscosity. Liquid products containing hydrocarbons, even if not harmful in the digestive system, may still be harmful if swallowed, if they can be aspirated into the lungs. The risk of aspiration is reduced if the viscosity of the liquid is relatively high. There are legal requirements in the United States and the European Union for minimum viscosities which must be met in order to avoid the need to label a product to indicate that it is toxic. Various perfume concentrates, e.g., essential oils, will contain hydrocarbons either in the form of compounds contributing to the odor or as inactive substances. Even if the major proportion of the concentrate consists of oxygenated materials, it may still be desirable to increase the viscosity, particularly as there may be some natural variation in the hydrocarbon content which may cause it to reach a given threshold level in some cases.

"Theoretical Organic Chemistry" by J. B. Cohen, 4th Edition (1942), explains in Chapter 10 that the fragrant oils which occur in flowers, fruits, leaves, and stems of plants are grouped together under the name of essential oils to distinguish them from the fixed oils and fats, and further explains that the essential oils contain terpenes and their derivatives. Various authors use the term "terpene" in various ways, but in this specification the term "terpenoid" which is defined below is used to cover hydrocarbons which can be notionally derived from isoprene units as well as the oxygenated derivatives.

Perfume concentrates are used in a variety of liquid products which are used to perfume rooms in buildings, for example, to mask undesirable odors. However, the use of conventional thickening agents, such as hydroxy ethylcellulose, in perfume concentrates, gives a cloudy solution. This will not be acceptable where the customer has been used to purchasing a perfume or deodorant product in the form of a clear solution.

There is another cellulose derivative used in solution to deposit lacquers. This is stated to dissolve a number of substances. We have found that it is not possible to obtain clear solutions when adding this to a number of common solvents. However, we have surprisingly found that in the special case where a solvent containing a terpenoid material is used, a clear solution of increased viscosity may be obtained by the use of a defined amount of this cellulose derivative.

DISCLOSURE OF THE INVENTION

According to the present invention, there is provided a composition comprising a viscosity-increasing amount of ethylcellulose dissolved in a liquid medium comprising a solubilizing proportion of a terpenoid material.

By "viscosity-increasing amount of ethylcellulose" we mean that the amount of ethylcellulose present in the composition is sufficient to give a significant increase in viscosity at normal ambient temperatures, e.g., at 25°C. Thus we prefer the viscosity to be increased to twice the viscosity without the ethylcellulose, more preferably to at least four times the viscosity without the ethylcellulose.

The quantity of ethylcellulose present (calculated as weight of ethylcellulose based on the total weight of composition) may be, for example, 1-10%, more preferably 1-5%.

By "solubilizing proportion" we mean that the liquid medium contains sufficient terpenoid material to give a clear solution as opposed to a hazy dispersion.

By "terpenoid material" we mean a material which contains a major amount of a compound having a carbon skeleton notionally derived from at least two isoprene molecules CsH . Preferably compounds having a carbon skeleton notionally derivable from at least two isoprene molecules constitute at least 50% by weight, more preferably 70% by weight, of the terpenoid material.

The "terpenoid solvent" may be a terpene proper derivable from two isoprene units, for example, an unsaturated cyclic hydrocarbon, with the double bonds in the ring, e.g. pinene (in oil of turpentine), or with one double bond in the ring and the other in a side chain, e.g., limonene (from oil of lemons). It may be an acyclic unsaturated hydrocarbon with three double bonds, e.g., ocimene (basil) or myrcene (bayberry).

The terpenoid material may also be an alcohol or aldehyde derived from a terpene hydrocrabon. Examples of acyclic alcohols are geraniol and citronella. Terpineol is an example of a cyclic terpene alcohol.

The terpenoid material may be a commercially available product based on an essential oil or on a synthetic material and sold as a perfume oil or fragrance concentrate, or as a component for use in making a fragrance concentrate, and such a commercial mixture may be the only component other than the ethylcellulose.

Many fragrance concentrates intended to be used in the final product intended to be used by individual consumers are mixtures of concentrated materials from various sources including synthetic materials and various essential oils. Depending on the nature of the fragrance which it is desired to provide, the fragrance concentrate may contain relatively small amounts of terpenoid material. However, the benefits of the invention can be obtained with at least some fragrance concentrates at relatively low contents of terpenoid material. Thus it may be possible to obtain clear solutions with fragrance concentrates containing more than 3% wt/wt of terpenoid materials. Preferably, the composition contains at least 10% by weight of terpenoid material, more preferably at least 20% by weight, most preferably at least 30% by weight.

The relative amounts of terpenoid material and non-terpenoid solvent which may mixed together and which will still give clear solutions with ethylcellulose will depend on the terpenoid material and the non-terpenoid solvent, but may be determined by the skilled person once the underlying idea has been explained by this specification. Ethylcellulose is commercially available, the example from the firm of Hercules.

Cellulose contains a chain of anhydroglucose units, each of which contains three replaceable OH groups. Although all three groups can be replaced (corresponding to a substitution value of 3), the commercial products have substitution values between 2.25 and 2.60 ethoxy groups per anhydroglucose unit or an ethoxyl content of 44% to 50%. Three different types of ethylcellulose are available from Hercules, namely K- type with ethoxyl contents between 46.1 and 47.2% (corresponding to a substitution value of 2.3 to 2.4), N-type with ethoxyl contents between 48.0 - 49.5 (substitution value 2.41-2.51), and T-type with a minimum ethoxyl content of 49.6 (substitution value of 2.55+). It is preferered to use ethylcellulose with a substitution value of at least 2.41.

Ethylcellulose is available in different viscosity types. Hercules classify the viscosity type of ethylcellulose by the viscosity in centipoise of a 5% solution at 25°C in a mixture of 80:20 toluene :ethanol. It is preferred to use an ethylcellulose with a viscosity type of at least 100, preferably at least 150.

BEST MODE OF CARRYING OUT THE INVENTION

Viscosity Comparisons

In some of the experiments set out below, comparisons are made between the viscosities of various liquids. Unless otherwise indicated, these comparisons were made using an ISO flow cup (ISO flow cup 2431 No. 3), a fixed volume of liquid is introduced into the flow cup. The time (in seconds) taken for liquid to flow out of an aperture in the base of the cup until a break in the flow is observed gives a measure of the viscosity of the liquid.

Comparative Test A

This is a comparative test not according to the invention. An isoparaffin hydrocarbon solvent, commercially available from Exxon under the trade name "Isopar L" (98.5 parts by weight) was introduced into a vessel provided with an agitator. Ethy cellulose (1.5 parts by weight) commercially available from Hercules was added to the vessel and the mixture agitated. The ethycellulose as T200, i.e., it had a substitution value of 2.55+ and a viscosity type of 200.

Although the mixture was agitated at room temperature (ca. 20°C) for 120 minutes, a clear solution was not obtained. The liquid was cloudy and rather dark.

Comparative Test B

An experiment was carried out as in Test A, except that the liquid was 96% ethanol, and agitation was continued for only 45 minutes. At the end of this time the liquid was still hazy.

Comparative Test C

An experiment was carried out as in Test B (i.e., using 96% ethanol) but using a different ethylcellulose. The Ethyulcellulose was N50 from Hercules. It thus had a lower substitution value and a lower viscosity type than the T200 used in the previous experiments. After stirring for 35 minutes, a completely clear solution was not obtained.

The liquid was slightly hazy.

Comparative Test D

An experiment was carried out as in Test A but using a firelighter product commercially available from S. C. Johnson and containing 99%w/w kerosene.

After 60 minutes stirring a clear solution was not obtained The liquid was cloudy.

Comparative Test E An experiment was carried out as in Test A but using benzyl acetate in place of the isoparaflfin solvent. Agitation for 20 minutes produced a cloudy liquid with white foam. Comparative Test F

An experiment was carried out as in Test A but using a commercially available liquid having an aromatic odor available from Firmenich under the designation as Base XI, which is understood to be based on a furanone derivative. After stirring for 30 minutes, the liquid was hazy and not all the ethylcellulose had dissolved.

Example 1

This is an example of the invention. An experiment was carried out as in Test A except that the liquid was a commercially available orange terpene oil available as Terp Orange BNC itrona available from Firmenich. This is stated to contain "terpenes and terpenoids, sweet orange oil".

After stirring for only 15 minutes, a clear solution was obtained. The viscosity of this solution at 24°C was compared with that of the orange terpene without ethylcellulose. The viscosity of the liquid containing ethylcellulose was nearly five times that of the liquid without ethylcellulose.

Example 2 This is an example of the invention.

An experiment was carried out as in Example 1 except that the Terp Orange was replaced by a 50%/50% (wt) mixture of Terp Orange and benzyl acetate. After stirring for 20 minutes, a clear solution was obtained. The viscosity of this solution at 24°C was compared with the viscosity of the mixture without ethylcellulose. The viscosity of the solution containing ethylcellulose was over two and a half times that of the liquid containing no ethylcellulose.

Comparative Test G

Ethylcellulose (1.5g) (T200 grade) was added to a fragrance concentrate used for producing scented candles, and identified as Vanilla RH-1500, and which contained no terpenes. The mixture was stirred at ambient temperature in an attempt to dissolve the ethylcellulose. The ethylcellulose was only partially dissolved and the solution was cloudy.

Comparative Test H An experiment was carried out as in Test G but using a fragrance identified as

Sweet Peach ANl 10037 which contained 2.1%wt/wt of the terpene limonene. The ethylcellulose dissolved by the solution was hazy.

Example 3 This is an example of the invention.

An experiment was carried out as in Comparative Test G but using a fragrance identified as Pine TD 13339 which contained a mixture of terpenoid materials in an amount of 3.75% wt./wt. A clear solution was obtained with a viscosity (at 24°C) nearly 8 times greater than that of the fragrance without ethylcellulose. The composition of the terpenoid mixture is given in Table 1.

Table 1 alpha-terpineol (CιnHι₈0) tertiary alcohol 1.48% alpha-terpinene (CioHi_δ) lemon/citrus terpene 0.34% limonene Cι₀Hι₆ 0.97% alpha-pinene monoterpene (CioHiβ) 0.22% beta-pinene C₁₀H₁₆ 0.42% camphene CιoHι₆ 0.26% camphor Cι₀Hι₆ 0.06% total 3.75

INDUSTRIAL APPLICABILITY

One use of these compositions is in products that dispense fragrance to be surrounding environment, also known as air fresheners.

Claims

Claims:

1. A composition comprising a viscosity-increasing amount of ethylcellulose dissolved in a liquid medium comprising a solubilizing proportion of a terpenoid material.

2. A composition according to claim 1 wherein the amount of ethylcellulose present is sufficient to give a viscosity at 25┬░ twice that of the composition in the absence of ethylcellulose.

3. A composition according to claim 2 wherein the amount of ethylcellulose is sufficient to give a viscosity at 25┬░ four times that of the composition in the absence of ethylcellulose.

4. A composition according to claim 1 wherein the quantity of ethylcellulose present is in the range 1 to 10% by weight based on the weight of the total composition.

5. A composition according to claim 4 wherein the quantity of ethylcellulose is in the range 1 to 5% by weight based on the total weight of the composition.

6. A composition according to claim 1 wherein the terpenoid material is an essential oil.

7. A composition according to claim 6 wherein the terpenoid material is a mixture of an essential oil and a non-terpenoid solvent.

8. A composition according to claim 1 wherein the terpenoid material contains a major amount of compounds having a CIO carbon backbone.

9. A composition according to claim 1 wherein material having a carbon skeleton notionally derivable from at least two isoprene molecules constitute at least 50% by weight of the terpenoid material.

10. A composition according to claim 9 wherein materials having a carbon skeleton notionally derivable from at least two isoprene molecules constitute at least 70% by weight of the terpenoid material.

11. A composition according to claim 1 which composition is a fragrance concentrate containing at least 3% by weight of a terpenoid material.

12. A composition according to claim 11 which contains at least 10% by weight of a terpenoid material.

13. A composition according to claim 1 wherein the ethylcellulose has a substitution value of 2.25 to 2.60.

14. A composition according to claim 13 wherein the ethylcellulose has a substitution value of at least 2.41.

15. A composition according to claim 1 wherein the ethylcellulose has a viscosity type of at least 100.