IE42325B1 - Improved air freshener gels - Google Patents

Abstract

The air freshener gel consists of a novel gelling agent and of an aqueous medium containing at least one volatile air freshener. The novel gelling agent contains carragheenin, carob gum and a water-soluble ammonium salt whose pH in aqueous solution is above 5.0. At least 40 % by weight of the carragheenin is chi -carragheenin. The novel air freshener gel shows virtually no synaeresis, improved gel stability and viscosity.

Description

This invention relates to improved gels; more particularly, it relates to a new gelling agent composition for such air freshener gels.

Air freshener gels and their gelling agents are well known. Generally, air freshener gels comprise an aqueous medium containing a volatile air freshener component and a gelling agent which gels the largely aqueous medium. Air freshener gels provide an ideal medium for freshening the air and are popular consumer products. ' Air freshener gels operate by continuously releasing the air freshener components from the gel by the room temperature evaporation of the aqueous medium within the gel.

The volatile air freshener components may include disinfectants, bactericides, insecticides, and odoriferous materials or oils which provide a pleasant odour and/or reduce unpleasant odours. - 2 42325 Heretofore, in accordance with U.S. Patent No. 2,927,055, air freshener gels were prepared by employing as a gelling agent a formulation of carrageenan, locust bean gum, and potassium chloride in conjunction with sodium carboxymethylcellulose. In accordance with the patent, the components and proportions of components of the formulation of gelling agent range as follows in percent, by weight, of the complete gel formulation; from 0.75 to 1.8% carrageenan, from 0.2 to 0.75% locust bean gum, from 0.1 to 0.75% potassium chloride and from 0.15 to 0.7% sodium carboxymethylcellulose.

In accordance with U.S. Patent No. 2,927,055, the air freshener gel is prepared by blending the components of the gelling agent in the dry state, adding the blended components to cold water, and heating the components to from 180 to 190°F. with stirring, until the solids are completely dispersed. The aqueous dispersion is then cooled to 170°F. and the pre-blended air freshener components added with stirring until a uniform dispersion results, transferring the dispersion to a moulding means and cooling to produce the formed gel.

In accordance with Canadian Patent No. 895,825, air freshener gels may be prepared using gelling agents comprising mixtures of specific carrageenan fractions, namely kappa and iota carrageenan. Specifically, the Canadian Patent teaches the use of a gelling agent composition in air freshener gels comprising kappa and iota fractions of carrageenan in which the weight ratio of the respective components is between 1.5:1 and 7:1. The Canadian Patent also teaches the optional addition of calcium and/or potassium ions in the form of their chlorides to the gelling agent composition. The optional addition of calcium or potassium ions to the gelling agent, in accordance with the Canadian Patent, is particularly useful when the gelling agent contains high concentrations oi kappa carrageenan.

The air freshener gels obtained in accordance with U.S. Patent No. 2,927,055 and Canadian Patent No. 895,825, have been found to exhibit undesirable gel syneresis, i.e., separation of the aqueous medium from the gel caused by gel contraction and/or inadequate water gel strength.

It has now been found that gel syneresis problems associated with the gelling agent combinations set forth in U.S. Patent No. 2,927,055 and Canadian Patent No. 895,825, have been overcome by the improved gelling agent composition according to the present invention. It was unexpectedly found that the three component gelling agent composition according to the present invention, when used to prepare air fresheners gels, yields an air freshener gel exhibiting negligible syneresis and improved water gel strength.

In accordance with the present invention there is provided an air freshener gel comprising from 1.5 to 4% of a gelling agent and from 98.5 to 96% of an aqueous medium containing a volatile air freshener component, the gelling agent comprising (a) a carrageenan comprising at least 40% by weight of kappa carrageenan, any remainder being substantially lambda carrageenan, the said carrageenan being present at a concentration in the range of from 0.6 to 2.0%, (b) a locust bean gum at a concentration in the range of from 0.2 to 1.0%, and (c) a water soluble ammonium salt having a pH greater than 5.0 the said salt being present at a concentration in the range of from 0.05 to 1.0%; wherein the said percent is percent by weight of the said air freshener gel. (Throughout the specification and Examples, all parts and percentages are by weight of the air freshener gel, unless otherwise noted.) ; The gelling agent according to the present invention is useful in the preparation of air freshener gels exhibiting negligible syneresis and improved water gel strength The gelling agent comprises carrageenan, locust bean gum and a water-soluble ammonium salt having a pH greater than 5.0. The term carrageenan is used herein to denote a sulphated polysaccharide containing at least 40%, by weight, of kappa carrageenan, any remainder being substantially lambda carrageenan. The carrageenan used according to the present invention may be derived from a class of seaweed known as Rhodophyceae (red algae), subclass Florldeae, and order Gigartlnales. Specifically, the carrageenan may be derived from species within the families Glgartinaceae, Solieriaceae, and Hypneaceae, Furcellarlaceae and combinations thereof. More specifically, the carrageenan may be derived from the genera Gigartina, Chondrus, Eucheuma, Hypena, Furcellaria, and combinations thereof. Most specifically, the carrageenan used according to the present invention may be derived from extracts of Gigartina stellata, Chondrus crlspus, Chondrus ocellatus, Eucheuma cottonii, Hypena musciformis, Furcellaria fastigiata, and combinations thereof. Ideally, the carrageenan used according to. the present invention is obtained from Chondrus crispus (Irish moss), Furcellaria fastigiata, and Hypnea musciformis.

The sulphated polysaccharides used according to the present invention are well known in the art and are more fully discussed in the following publications: Polysaccharide Gels by Reese, D. A., Chemistry and Industry, Vol. 19, p. 630 (1972).

Lerring, T., Hoppe, II. A., Schmid, O. J., Marine Algae, p. 342, Cram, DeGruyter & Co. (1969).

The carrageenan used according to the present invention may be recovered from dried seaweed by first washing the dried seaweed with water, extracting the washed seaweed at an alkaline pH, removing the residue by filtration, drying the extract, and milling the dried carrageenan extract. Any commercially available carrageenan containing at least 40%, by weight, of kappa carrageenan obtained from the genera and species previously mentioned may be used in the gelling agent according to the present invention.

The locust bean gum used according to the present invention is readily available and generally contains about 88% of Dgalacto-D-mannoglycan, 4% pentan, 6% protein, 1% cellulose and 1% ash. Locust bean gum is also known by other names such as carob gum, gum gatto, gum hevo, jandagum, lakee gum, Rubigum, Lupogum, Luposol, gum Tragon, Tragarab, and Tragasol. Locust bean gum is chemically characterized as a neutral polysaccharide containing substantially D-galacto-D-mannoglycan.

By water-soluble ammonium salt having a pH greater than 5.0 is meant an ammonium salt such as ammonium sulphate, ammonium acetate, ammonium phosphate (dibasic), ammonium chloride or a mixture thereof. Preferably, the ammonium salt used according to the present invention is selected from ammonium sulphate, ammonium acetate, ammonium phosphate (dibasic), ammonium chloride, or mixtures thereof. Most preferably, the ammonium salt used according to the present invention is ammonium chloride.

The ammonium chloride is generally added to the other incredients tn dried form. Any commercially available ammonium chloride, i.e., technical or reagent grades, may be used in the gelling agent composition according to the present invention.

In accordance with the present invention, the gelling agent comprises carrageenan containing at least 40%, by weight, of kappa carrageenan, in the range of from 0.6 to 2.0%; locust bean gum in the range of from 0.2 to 1.0%; and a water-soluble ammonium salt having a pH greater than 5.0 in the range of from 0.05 to 1.0%. Preferably, the gelling agent according to the present invention comprises carrageenan containing at least 40%, by weight, of kappa carageenan, in the range of from 1.0 to 1.8%; locust bean gum in the range of from 0.4 to 0.8%; and a water-soluble ammonium salt having a pH greater than 5.0 in the range of from 0.5 to 1.0%. Most preferably, the l gelling agent according to the present invention comprises about 1.5% carrageenan containing at least 40%, by weight, of kappa carrageenan, about 0.6% locust bean gum; and about 0.75% ammonium chloride.

The above-described ranges indicated for the components of the gelling agent according to the present invention have been found necessary to provide air freshener gels exhibiting negligible syneresis, improved water viscosity and water gel strength. However, the respective ranges of components in the gelling agent composition may be varied within the ranges indicated above to provide air freshener gels exhibiting various degrees of water viscosity, water gel strength and syneresis, which may be desirable for particular applications.

In formulating air freshener gels, the gelling agent according to the present invention typically comprises from 1.5 to 4¾ of the total air freshener gel while the aqueous medium containing an air treating component comprises the remaining 98.5 to 96%. It is preferred that the air freshener gels should contain from 2.5 to 3.0% of gelling agent and from 97.5 to 97.0% of aqueous medium. The air treating components comprises from 2 to 10% of the aqueous medium.

By air treating components is meant perfumes, bactericides, essential oils, fungicides, or other desirable air treating components, or mixtures thereof. Preferably, the air treating component is a volatile material at room temperature, compatible with other components in the air freshener gel and dispersible in aqueous medium. Oils useful for overcoming malodours may be used, such as oil of rose, oil of lime,' oil of pine, oil of lemon, oil of spearmint, oil of Wintergreen, oil of cedar wood and oil of fir Canadian. The oils mentioned above may also be used in combination with fragrances, such as aromatic esters, aldehydes, ketones and other compounds known to those skilled in the art of blending fragrances.

In addition, the aqueous medium of the air freshener gel may contain carrier agents which provide increased solubility for the particular oils and fragrances used in tho aqueous medium of the air freshener gel. The carrier agents may be present .in the aqueous medium of the air freshener gel in the range of from 2 to 5%. Typically, the carrier agents comprise ethanol, isopropanol, ethylene glycol, propylene glycol, hexylene glycol or Cellosolve (Registered Trade Mark).

Also, the aqueous medium of the air freshener gel may contain bactericides or fungicides to inhibit microbial or fungal growth within the air freshener gel. The bactericides - 8 42325 or fungicides may be present in the aqueous medium of the air freshener gel in an amount of from 0,001% to 0.01%. Typically, the bactericide or fungicide includes sodium benzoate, methyl butyl, or propyl-parahydroxy benzoate or mixtures thereof.

Also, the aqueous medium of the air freshener gel may contain water-soluble or oil-soluble dyes which impart colour to the air freshener gel. Particularly, the water-soluble or oil-soluble dyes may be present in the aqueous medium of the air freshener gel in an amount of up to 0.05%. Typical examples of suitable water-soluble or oil-soluble dyes are Rose Bengal dye, Uramine dye and Rhodamine dye.

In addition, the aqueous medium of the air freshener gel may contain emulsifiers well known in the art. The emulsifiers may be anionic, such as the alkyl sulphonates, alkyl sulphates, or allyl ether sulphates,or may be non-ionic compounds, such as the polyethoxylate ethers, sorbitan esters, or polyethoxylates or sorbitan esters.

The air freshener gels according to the present invention ate typically prepared as follows: dry blending the gelling agent components, i.e., carrageenan, locust bean gum, and ammonium chloride; dispersing the dry blended gelling agent components in water having a temperature below 90°F. with stirring; heating the dispersed gelling agent to a temperature between 150 and 19O°F. with stirring until the dispersed gelling agent is completely dissolved; cooling the aqueous solution of gelling agent to a temperature between 135 and 150°F; adding an air treating agent to the cool solution of gelling agent while stirring to provide a uniform mixture of air freshener components; and cooling to a temperature below 100°F. to cause - 9 42325 gel formation and provide the air freshener gel. Preferably,the dispersed gelling agent is heated to a temperature of about 180°F..with stirring until the solids are completely dissolved. Also, it is preferred that the uniform mixture of air freshener gel be poured into a suitable container or mould so as to provide a gel body having the desired shape.

The following Examples illustrate the invention. (All parts and percentages are by weight unless otherwise noted.) EXAMPLE 1.

The air freshener gel may be prepared using the gelling agent composition according to the present invention as follows: 500 grams of air freshener gel were prepared by first dry blending 7.5 grams of carrageenan, 3.0 grams of commercial grade locust bean gum, and 3.75 grams of reagent grade ammonium chloride. The carrageenan comprises substantially kappa carrageenan, i.e., from 70 to 80% kappa carrageenan and from 20 to 30% lambda carrageenan. The carrageenan used in this Example was obtained from Stauffer Chemical Company as an extract of Chondrus crispus (Irish Moss).

The dry blended gelling agent was thereafter dispersed in about 440 grams of water by stirring. The dispersed gelling agent was then heated to a temperature of about 180°F. with stirring until the dispersed solids were dissolved. The gelling agent solution was then allowed to cool to about 150°F.

The weight of the gelling agent solution was adjusted to 460 grams by the addition of water. To the gelling agent solution, at a temperature of about 150°F. there was added 40 grams of the air treating agent comprising 6.6 grams of oil of lemon, 3.3 grams of oil of lime, 20 grams of isopropyl alcohol, 10 grams of ethylene glycol and 0.1 gram of Uramine dye.

The mixture was then blended to provide a uniform air 4 2325 freshener dispersion. The air freshener dispersion was then poured into crystallizing dishes measuring 7.0 centimetres in diameter by 5.0 centimetres in depth. The air freshener dispersion was then allowed to cool to room temperature to provide an air freshener gel.

Air freshener gel syneresis was determined as follows: the crystallizing dish containing the air freshener gel was covered with paraffin paper and stored in a constant temperature incubator at 40°F. After overnight incubation, the air freshener gel was removed from the incubator and allowed to equilibrate to room temperature. The paraffin paper was then removed from the air freshener gel and the gel carefully tapped into a pre-weighed paper towel. The air freshener gel was then rotated on the paper towel to allow the paper towel to absorb excess liquid from the gel. The weight of the air freshener gel and the weight of the paper towel were then determined.

The present syneresis is expressed as the amount of liqliid absorbed by the paper towel, divided by the total gel weight, multiplied by 100.

The air freshener gel sample in Example 1 was found to exhibit a syneresis rate of less than 0.3%, determined as described above. Visually, the air freshener gel prepared in accordance with Example 1 exhibited no apparent syneresis. Therefore, air freshener gels exhibiting less than 0.3% syneresis, determined as described above, exhibit negligible syneresis, i.e., no free flowing liquid may be seen.

The water viscosity of the air freshener dispersion was determined as follows. The water viscosity of the air freshener dispersion was determined at 145°F. using a Brookfield viscosimeter, model LVT, using the appropriate spindle - 11 42335 and rotation rate. The water viscosity of the air freshener dispersion was 1100 centipoise, determined as described above.

The water gel strength of the air freshener gel was determined in a gel tester, Model GT —3 from Marine Colloids, Inc. The gel tester was used with a flat head plunger measuring 0.431 inches in diameter. A dietetic scale was placed directly beneath the plunger and was used to measure the break force required for the plunger to penetrate the gel material being measured. After the syneresis evaluation, the air freshener gel was placed in a crystallizing dish. The water gel strength was then determined by placing the crystallizing dish containing the air freshener gel sample to be measured on top of the scale. The scale was then zeroed and the flat head plunger brought down onto the surface of the gel material. The plunger was continuously forced into the gel until a maximum force required to break the gel surface was indicated. The weight indicated on the scale required to break the gel surface for the sample of Example 1 was 710 grams.

The Composition of the air freshener gel prepared in accordance with Example 1 is set forth in Table 1. The results of the air freshener evaluation relating to water, viscosity, water gel strength and syneresis are shown in Table VI.

TABLE I.

Air Freshener Gel Composition—Example No. 1.

Ingredients Percent (by weight of final gel) Gelling Agent Carrageenan Locust Bean Gum 1.5 0.6 Ammonium Chloride 0.75 i2 Air Treating Components Oil of Lemon 1.33 Oil of Lime 0.67 Isopropyl Alcohol 4.0 Ethylene Glycol 2.0 Uramine Dye 0.02 Aqueous Medium Water 89.13 EXAMPLE 2.

This Example represents a control sample of air freshener gel prepared in accordance with Example I of U.S. Patent No. 2,927,055. The air freshener gel was prepared in accordance with the process described in Example 1 above. The resulting air freshener gel composition is presented in Table II TABLE II.

Air Freshener Gel Composition (control).

Ingredients Percent (by weight of final gel) Gelling Agent Carrageenan 1.5 Locust Bean Gum 0.25 Potassium Chloride 0.5 Sodium Carboxymethyl Cellulose 0.25 Air Treating Components Oil of Rose 3.0 Isopropyl Alcohol 4.0 Ethylene Glycol 2.0 Water-Soluble Chlorophenyl 0.1 Aqueous Medium Water 88.40 - 13 42325 The water viscosity, water gel strength and syneresis were determined as previously described in Example 1. The re suits of the air freshener evaluation relating to water visco sity, water gel strength and syneresis are shown in Table VI.

Example 3.

This example also describes a control sample. An air freshener gel was prepared in accordance with Example 1 of Canadian Patent No. 895,825. The air freshener gel was prepared by the method set forth above in Example 1. The composition of the resulting air freshener gel is set . forth below in Table III.

TABLE III.

Air Freshener Gel Composition.

Ingredients Percent (by weight of final gel) Gelling Agent Carrageenan Kappa 2.33 Iota 0.67 Air Treating Component Oil of Lemon 2.31 Oil of Lime , 1.00 Ethylene Glycol 4.0 Sodium Chlorophyllin 0.5 Emulsifier (Tween 20, Atlas Chemical Company, (Tween is a Trade Mark) 1.88 Sodium Benzoate 0.1 Aqueous Medium Water 87.21 The air freshener gel prepared in accordance with Example 3 were evaluated with respect to water viscosity, water gel strength and syneresis, in accordance with the - 14 42325 1' methods set forth in Example 1. The results of the air freshener gel evaluation are shown in Table VX.

Example 4.

This example also describes a control sample.

An air freshener gel was prepared using the composition set forth in Example 2 of Canadian Patent No. 895,825. The method of preparation of the air freshener gel was as set forth in Example 1 above. The composition of the resulting air freshener gel is set forth below in Table IV.

TABLE IV.

Air Freshener Gel Composition Ingredients Percent (by weight of final gel) Gelling Agent Carrageenan Kappa 2.0 iota 0.3 Calcium Chloride 0.75 Air Treating Components Oil of Rose 2.0 Ethyl Alcohol 3.0 Rose Bengal Dye 0.5 Emulsifier (Tween 20, Atlas Chemical Company) 1,0 Sodium Benzoate 0.1 Aqueous Medium Water 90.35 The air freshener gel prepared as described above was evaluated with respect to water viscosity, water gel strength and syneresis. The results of this evaluation are set forth in Table VI.

EXAMPLES 5—9.

In Examples 5—9, air freshener gels were prepared in accordance with the method set forth in Example 1 above. The gelling agent compositions were varied as set forth below in Table V. The air freshener gels prepared in accordance with Examples 5—9 were evaluated with respect to water viscosity, water gel strength and syneresis, as previously set forth in Example 1, The results of these evaluations are set forth in Table VI.

EXAMPLES 10 and 11.

In Example 10, an air freshener gel was prepared using carrageenan obtained from Chondrus crispus containing about 80%, by weight, of the carrageenan, kappa carrageenan. The air freshener gel composition is set forth in Table V. The method of preparation of air freshener gel for this Example was as set forth in Example I above.

In Example 11, an air freshener gel was prepared using a polysaccharide extract from Hypena musciformis corresponding to carrageenan. The composition of the air freshener gel prepared with this particular gelling agent combination is set forth in Table V. The method of preparation of air freshener gel in this Example was as set forth above in Example 1.

Examples 10 and 11 were evaluated with respect to water viscosity, water gel strength and syneresis as set forth above in Example 1. The results of these evaluations are set forth in Table VI. ω μί ra Η 3 φ co οΟ 00 00 co CO CO •Η +> σι σι ιη οι ΟΙ Οί τί (ΰ • • • • • • Φ £ 00 σι 00 Ο σι σι σι S 00 00 00 σι 00 00 00 ω Ρ Ο ω ϋ σ1 Οί ΟΙ Ο »8 ο τί ο »0 Ο Οί ο τι Ο τ* ο *ϋ ο τι Ο *α ο τι ο ΓΟ ο *ϋ m ιη ιη ο ΓΟ Γ- νο rd γ* Γ- • • rd Ο ο Ο ο Ο Ο μ 3 ιπ ϋ □ α c ο « μι φ ra φ rd Οι ιη ι> ό Ο ιο Ο ιη ιη Ο Ο ιη M3 ο γο ΓΟ Η ΟΙ rd ο Οί r-i rd VI •Η IΒ Μ Ο ΐμ ιμ -rl β ϋ nJ ω CJ 2 Q) g; Φ 0^ rd (d Φ μ ώ μ α υ ra’ φ ω ο ra Md ο »Η •ri Ο φ >1 Q rd id tP β Φ « Φ (0 ο ra -42325 TABLE VI Air Freshener Gel Evaluation Example Water Viscosity (Centipoise) Water Gel Strength (grams) Syneresis (Percent) 1 1100 710 0.20 2 260 690 0.67 3 477 88 0.27 4 105 87 0.44 5 2632 705 0.17 6 214 463 0.21 7 2064 697 0.21 8 390 517 0,34 9 2308 690 0,34 10 728 727 0,16 11 347 727 0.26 It is apparent from Table Vf with respect to Examples I >' -11, that the air freshener gel prepared using the gelling agent composition according to the present invention exhibits improved physical properties in that the level of syneresis is below 0.5%, the water gel strength is above 400 grams and the water viscosity is below 2700 centipoise. In contrast, it is apparent from Table VI, Example 2, that air freshener gels prepared in accordance with U.S. Patent No. 2,927,055, wherein gelling agents are used comprising carrageenan, locust bean gum, potassium chloride and carboxymethylcellulose, exhibit an undesirable level of gel syneresis, i.e,, 0.67%.

Also, it is apparent from Table VI, Example 3, which represents an air freshener gel prepared in accordance with Example 1 of Canadian Patent No. 895,825, wherein an air freshener gel is prepared using a gelling agent comprising kappa carrageenan and iota carrageenan, that the water gel strength of the air freshener gel is undesirable, i.e., 88 grams. With respect 42335 to water gel strength, it has been found that air freshener gels exhibiting water gel strength less than 400 grains are undesirable because the gel is incapable of retaining its original shape. Furthermore, it is apparent from Table VI, Example 4, which represents an air freshener gel prepared in accordance with Example 2 of Canadian Patent No. 895,825, wherein a gelling agent comprising kappa carrageenan iota carrageenan and calcium chloride is used, that the air freshener gel exhibits undesirable water gel strength, i.e., 87.

It is apparent from Table VI, Examples 5—9 that air freshener gels may be prepared using the gelling agent composition according to the present invention, i.e., carrageenan, locust bean gum and ammonium chloride. The level of syneresis, water gel strength and water viscosity as set forth in Table VI, are well within the desirable limits required for these evaluation parameters.

It is apparent from Table VI, Examples 10 and 11 that air freshener gels exhibiting desirable water viscosity, water gel strength and syneresis properties may be prepared using gelling agents containing substantially kappa carrageenan, as indicated by Example 10, and a polysaccharide extract from Hypena musciformis.

Claims (13)

1. An air freshener gel comprising from 1.5 to 4% of a gelling agent and from 98.5 to 96% of an aqueous medium containing a volatile air freshener component, the gelling agent comprising (a) a carrageenan comprising at least 40%, by weight, of kappa carrageenan, any remainder being substantially lambda carrageenan, the said carrageenan being present at a concentration in the range of from 0.6 to 2.0%, (b) a locust bean gum at a concentration in the range of from 0.2 to 1.0%, and (c) a water-soluble ammonium salt having a pH greater than 5.0, the said salt being present at a concentration in the range of from 0.05 to 1.0%; wherein the said percent, is percent by weight of I lie said air freshener gel.

2. A'gel according to claim 1 wherein the said carrageenan is obtained from extracts of Rhodophyceae, sub-class Florideae, order Gigarfinales, and family selected from Gigartinaceae, Solieriaceae, Hypenaceae, Furcellariaceae, and combinations thereof.

3. A gel according to claim 1 wherein the said carrageenan is obtained from extracts of Rhodophyceae of the genera selected from Gigartina, Chondrus, Eucheuma, Hypena, Furcellaria, and combinations thereof.

4. A gel according to claim 1 wherein the said carrageenan 20 4 2325 is obtained from extracts of Rhodophyceae of a species selected from Gigartina stellata, Chondrus crispus, Chondrus ocellatus, Eucheuma cottonii, Hypena musciformis, Furcellarla fastigiata, and combinations thereof. 5. A gel according to claim 4 wherein the species is Chondrus crispus. 6. A gel according to claim 4 wherein the species is Furcellaria fastigiata. 7. A gel according to claim 4 wherein the species is Hypena musciformis.

5. 8. An air freshener gel according to claim 1 wherein the gelling agent comprises: (a) a carrageenan comprising at least 40%, by weight, of kappa carrageenan, the said carrageenan being present at a concentration in the range of from 1.0 to 1.8%, (b) a locust bean gum at a concentration in the range of from 0.4 to 0.8%, and (c) a water-soluble ammonium salt having a pH greater than 5.0, the said silt being present at a concentration in the range of from 0.5 to 1.0%.

6. 9. An air freshener gel according to claim 8 wherein the said water-soluble ammonium salt is selected from ammonium chloride, ammonium sulphate, ammonium acetate, ammonium phosphate (dibasic), or mixtures thereof.

7. 10. An air freshener gel according to claim 9 wherein the said gelling agent comprises: (a) a carrageenan containing at least 40%, by weight, of kappa carrageenan the said carrageenan being present at a concentration of about 1.5%, 21 42325 (b) a locust bean gum at a concentration of about 0.6%, and (c) ammonium chloride at a concentration of about 0.75-%.

8. 11. An air freshener gel comprising from 2.5 to 3.0% of a gelling agent and from 97.5 to 97% of an aqueous medium containing a volatile air freshener component, the gelling agent comprising (a) a carrageenan containing at least 40%, by weight, of kappa carrageenan, any remainder being substantially lambda carrageenan, the said carrageenan being present at a concentration in the range of from 1.0 to 1.8%, (b) a locust bean gum at a concentration in the range of from 0.4 to 0.8%, and (c) a water-soluble ammonium salt selected from ammonium chloride, ammonium sulphate, ammonium acetate, ammonium phosphate (dibasic), or mixtures thereof, the said salt being present at a concentration in the range of from 0.5 to 1.0%; wherein the said percent is percent by weight of said air freshener gel.

9. 12. A gel according to claim 11 wherein the said carrageenan is obtained from extracts of Rhodophyceae of the genera selected from Gigartina, Chondrus, Eucheuma, Hypena, Furcellaria, and combinations thereof.

10. 13. A gel according to claim 11 wherein the said carrageenan is obtained from extracts of Rhodophyceae of a species selected from Gigartina stellata, Chondrus crispus, Chondrus ocellatus, Eucheuma cottonii. 42335 Hypena musciformis, Furcellaria fastigiata, and combinations thereof.

11. 14. A gel according to claim 13» wherein the species is Furcellaria fastigiata. 15. A gel according to claim 13 wherein the species is Hypena musciformis. 16. A gel according to claim 13 wherein the species is Chondrus crispus. 17. A gel according to claim 11 wherein the gelling 10 agent comprises s (a) a carrageenan containing at least 40%, by weight of kappa carrageenan, the said carrageenan being present at a concentration of about 1.5%, (b) a locust bean gum at a concentration of about 0.6%,

12. 15 and (c) ammonium chloride at a concentration of about 0.75%.

13. 18. An air freshener gel as claimed in claim 1 substantially as herein described with reference to the Examples.