WO1990000859A1

WO1990000859A1 - Insect repellant

Info

Publication number: WO1990000859A1
Application number: PCT/AU1989/000316
Authority: WO
Inventors: Peter James Stanley; Gordon Robert Mckenzie
Original assignee: Nelson & Robertson Pty. Ltd.
Priority date: 1988-07-26
Filing date: 1989-07-26
Publication date: 1990-02-08

Abstract

Insect repellant active ingredients can be formulated with ordinary soap when particular fillers are incorporated in the composition. The invention provides an insect repellant soap composition comprising (a) from 60 % to 75 % by weight of toilet soap base; (b) from 10 % to 15 % by weight of a filler capable of absorbing moisture; (c) from 18 % to 20 % by weight of an insect repellant; (d) 0 % to 0.3 % by weight of terpinol; (e) 0.2 % to 0.3 % by weight of a binding agent; (f) 0.25 % to 2 % by weight of an insecticide; and (g) when the filler is full cream milk powder or skim milk powder, 0.05 % to 0.3 % by weight of a preservative. All percentages by weight being based on the total weight of the composition.

Description

INSECT REPELLANT

TECHNICAL FIELD

This invention relates to an insect repellant composition based on a soap base, to a process for its manufacture and to a method of repelling and/or killing insects with the composition.

BACKGROUND ART

Insects are the most numerous living organisms on earth and are said to constitute 70% of all animal species. Around 1% of insects are considered significant pests.

Malaria is a significant disease transmitted by the bite of the

Anopheles mosquito. There are in the order of 100 million clinical cases resulting in about one million deaths annually worldwide.

There are many insect repellants available based on lotions, pastes, creams, gels and sprays. Most are costly to produce and are useful for short durations only as they can be easily removed from the skin.

Schreck et al. J. Trop. Med. Hyg., 33(4), 1984. pp725-730 report that a combination of deet (N,N-diethyl-3-methylbenzamide) and permethrin

[(3-phenoxyphenyl)-methyl-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate] is more effective than either alone for protection against Aedes taeniorhynchus.

US 4707 496 describes a soap-based insect repellant composition where the soap is derived from coconut oil. The composition is said to be capable of containing high percentages of active ingredients which are incompatible with ordinary soap bases. It is stated that such ingredients cannot be incorporated in ordinary soap bases even by boiling as boiling would destroy the active ingredients.

Yap J. Am. Mosq. Control Assoc. reports that soap based insect repellant formulations supplied by the assignee of US 4707496 are effective against Aedes albopictus, Mansonia uniformus, Culex gelidus,

Anopheles lesteri and Armigeres subalbatus.

OBJECTS OF THE INVENTION

It is an object of the present invention to provide an insect repellant formulated with ordinary soap, which can be manufactured by the boiled soap process.

It is a further object of the invention to provide an insect repellant formulated with soap which can be produced more economically than prior art soap-pased insect repellant formulations.

A further object of the invention is to provide a method for removal of headlice by employing the soap-based insect repellant formulations of the invention as a shampoo.

There are several problems in manufacturing formulations according to US 4707496 because of the cold process employed. Unless the process is conducted in a proper manner, poor quality finished product is produced. Incomplete saponification frequently occurs and high quality raw materials must be used. The alkali employed should be virtually free from heavy metals and demineralised water must be used. Precautions need to be taken to prevent absorption of carbon dioxide by the alkali employed. The oils employed in manufacturing the soap base for US 4707 496 need to be of a higher grade than is necessary with the present invention. Saponification values are of vital importance to the process of US 4707 496 (free fatty acid content should not exceed 3 to 5%) but are of no particular importance in the manufacture of boiled soaps. In the manufacture of soap bases for use in US 4707 496, the process, once started, cannot be heated and must be completed, otherwise the batch must be wasted.

Any formulated or part formulated product spilled in the manufacture of formulations according to US 4707 496 cannot be reused and hence contributes to the greater cost of such formulations.

DESCRIPTION OF THE INVENTION

The present invention is based on the discovery that insect repellant active ingredients formerly believed to be incompatible with ordinary soap, can be formulated with ordinary soap when particular fillers are

incorporated in the composition.

The invention therefore provides an insect repellant soap composition comprising

(a) from 60% to 75% by weight based on the total weight of the composition of toilet soap base;

(b) from 10% to 15% by weight based on the total weight of the composition of a filler capable of absorbing moisture;

(c) from 18% to 20% by weight based on the total weight of the composition of an insect repellant;

(d) 0% to 0.3% by weight based on the total weight of the

composition of terpinol;

(e) 0.2% to 0.3% by weight based on the total weight of the composition of a binding agent;

(f) 0.25% to 2% by weight based on the total weight of the

composition of an insecticide; and (g) when the filler is full cream milk powder or skim milk powder, 0.05% to 0.3% by weight based on the total weight of the composition of a preservative.

The invention also provides methods for the protection of mammals, especially humans, against insects such as flies and mosquitoes, which method comprises applying to exposed skin of the mammal, an effective amount of a composition of the invention.

The invention further provides a method of eradicating headlice, which method comprises shampooing the hair with the composition of the invention.

In another aspect, the invention provides a process for the

manufacture of the above-described compositions, which process comprises blending the ingredients of the composition until uniformly distributed, extruding the mixture into its desired shape and allowing the shapes to harden. An advantage of the present invention over that of US 4707 496 is that any waste material from the mixer or extruder can be recycled, whereas that of US 4707496 can not be recycled and accordingly, the active ingredients must be wasted.

The compositions of the invention are capable of being formulated at or near to ambient temperature so that ingredients affected by heat are not damaged during processing.

The compositions of the invention may also contain perfumes, dyes and pigments which are non-irritant to the skin.

BEST MODES OF CARRYING OUT THE INVENTION

The preferred insect repellant soap composition according to the invention comprises 71.9% by weight based on the total weight of the composition of toilet soap base, 7.1% by weight based on the total weight of the composition of a filler, 20% by weight based on the total weight of the composition of an insect repellant, 0.25% by weight based on the total weight of the composition of terpinol, 0.25% by weight based on the total weight of the composition of a binding agent, 0.5% by weight based on the total weight of the composition of an insecticide, and when the filler is full cream milk powder or skim milk powder, 0.25% by weight based on the total weight of the composition of a preservative.

The preferred toilet soap base is a commercial toilet soap based on 85% tallow and 15% coconut oil. This results in a soap mixture containing about 1.2% of a soap of octanoic acid, about 1.1% of a soap of decanoic acid, aoout 7.2% of a soap of lauric acid, about 4.3% of a soap of myristic acid, about 29.0% of a soap of palmitic acid, about 12.7% of a soap of stearic acid, about 42.1% of a soap of oleic acid, and about 2.6% of a soap of linoleic acid. The tallow/coconut oil is preferably saponified with sodium hydroxide. Any commercially available toilet soap base can be used as the soap base in the present invention.

The filler is preferably full cream milk powder, skim milk powder or starch. The full cream milk powder filler is made from pure whole milk which is standardized, pasteurized, evaporated, homogenized and spray dried. The skim milk filler is made by spray drying evaporated pure pasteurized skim milk. Household starch is also suitable as a filler.

The amount of filler employed in the compositions of the invention will depend on the moisture content of the soap base. The drier the soap base, the less filler is required to achieve a composition which can be extruded into bars.

Any insect repellant which does not irritate the skin and which is compatible with the soap base may be used. Suitable insect repellants include N,N-diethyl-3-methylbenzamide (deet), N,N-diethyl-2-ethoxybenzamide, N,N-dipropyl-2- benzyloxyacetamide, 1-butyl-4-methylcarbostyryl, N,N-dipropyl-1,2- ethoxybenzamide,

2-butyl-2-ethyl-1,3-propanediol, 1,3-bis-butoxymethyl-2- imidazolidone, hexachlorophenol, 1,3-propanediol monobenzoate, diisobutyl malate, ethyl hexanediol, dibutyl phthalate, butyl-3,4-dihydro-2,2-dimethyl-4-oxo-2h-1,3-oxazine, 1,5a,6,9,9a,9b- hexahydro-4a-(4H)-dibenzofurancarboxaldehyde, di-n-propyl-2,5-pyridine- dicarboxylate, and 3-acetyl-2-(2,6-dimethyl-5-heptenyl)-oxazolidine.

Terpinol may be included as a gloss agent. It is preferably included in an amount of 250g ± 10% per 100kg of formulation. Other gloss agents may also be employed.

Propylene glycol is the preferred binding agent. Other suitable binding agents include glycerine, lanoline or any greasy agent which complies with standards for cosmetic ingredients. The binding agents are preferably incorporated in an amount of 250g ± 10% per 100kg of the composition.

The insecticides useful in the composition of the invention should be non-irritant to the skin and compatible with the soap base. Residual insecticides are preferred. Most preferred are the synthetic pyrethroids which include allethrin [2-methyl-4-oxo-3-(2-propenyl)-2-cyclopent-1-yl-2.2-dimethyl-3-(2-methyl-1-propenyl)-eyelopropanecarboxylate], cyfluthrin [cyano-(3-phenoxy-4-fluorophenyl)-methyl-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate], cyhalothrin [cyano-(3-phenoxyphenyl)-methyl-3-(2- chloro-2-trifluoromethylvinyl)-2,2-dimethyleyelopropanecarboxylate], cypermethrin [cyano-(3-phenoxyphenyl)-methyl-3-(2,2-dichlorovinyl)-2,2- dimethylcyclopropanecarboxylate], cyphenothrin [cyano-(3-phenoxyphenyl)- methyl -2,2-dimethyl-3-(2-methyl-1-propenyl)-cyclopropanecarboxylate], decamethrin [(lR-[lα(S*),3α.])-cyano-(3-phenoxyphenyl)-methyl-S-(2,2- dibromovinyl)-2,2-dimethylcyclopropanecarboxylate], dimethrin [(2,4- dimethylphenyl)-methyl-3-(2,2-dimethylvinyl)-2,2-dimethylcyclopropanecarboxylate], fenvalerate [cyano-(3-phenoxyphenyl)-methyl-4-chloro-α- (1-methylethyl)-phenyl acetate], flumethrin [cyano-(3-phenoxy-4-fluorophenyl)-methyl-3-(2-chloro-2-[4-chlorophenyl]vinyl)-2,2-dimethylcyclopropanecarboxylate], permethrin [(3-phenoxyphenyl)-methyl-3-(2,2-dichlorovinyl)- 2,2-dimethylcyclopropanecarboxylate], phenothrin [(3-phenoxyphenyl)-methyl-2,2-dimethyl-3-(2-methyl-1-propenyl)-cyclopropanecarboxylate], resmethrin [(5-benzyl-3-furyl)-methyl-3-(2,2-dimethylvinyl)-2,2-dimethylcyclopropanecarboxylate], tralocythrin [cyano-(3-phenoxyphenyl)-methyl-3-(1,2-dibromo-2,2-dichloroethyl)-2,2-dimethylcyclopropanecarboxylate] and tralocythrin

[cyano-(3-phenoxyphenyl)-methyl-3-(1,2,2,2-tetrabromoethyl)-2,2-dimethylcyclopropanecarboxylate]. Synthetic pyrethroids are preferably included at 0.5% or 1% by weight based on the total weight of the composition.

Permethrin is the preferred synthetic pyrethroid.

A suitable preservative for the milk powder is EDTA (ethylenediamine tetraacetic acid) or one of its salts. When EDTA is present, it is

preferred that it is incorporated in an amount of 70 to 250g per 100kg of the composition.

The compositions of the invention may also include known ultra-violet absorbing compounds so as to provide both a sunscreening and insect

repelling function.

The preferred process for manufacturing the compositions of the invention involves loading the soap base into a revolving drum which has internal baffles, adding the remaining ingredients other than the filler, mixing until the ingredients are uniformly distributed in the soap base, adding the filler and continuing mixing to achieve uniform distribution, dumping the contents of the drum into a screw feed extruder and cutting the extruded product into bars. To achieve a better uniform distribution of ingredients, the bars may be re-looped through the extruder one or more times. The bars are then allowed to harden and are packaged. The following examples illustrate the manufacture of compositions according to the invention. The examples are to be construed as

illustrative only and do not serve to limit the scope of the invention.

EXAMPLE 1

Commercial toilet soap noodles (71.9kg) based on 85% tallow and 15% coconut oil having between 11 and 13% by weight moisture were loaded into a tumble mixer. N,N-diethyl-3-methylbenzamide (20kg, terpinol (0.25kg), propylene glycol USP (0.25kg), permethrin 25/75 (0.5kg), full cream milk powder, NZ Finest Grade (7.1kg) and disodium ethyl enediamine tetraacetate (70g) were added and mixing continued for 5 min. The mixture was

transferred to a simplex or duplex plodder equipped with a cutter and extruded and cut into fine shavings then put through the plodder again to assist in thorough mixing and blending. The mixture is then extruded in bar formand is then cut into tablets or stamped into desired shape and packaged. The pressure applied to the plodder was in the order of

30t.cm_-1 Apart fron refrigeration of stamper heads, no heating or cooling need be employed during manufacture.

Alternative manufacturing processes may be employed. Any processes suitable for manufacture of bars of toilet soap can be used to manufacture the compositions of the invention. The filler is preferably added to the mixer with the soap base or is added last. The mixture may be recycled through the extruder/cutter until the desired uniformity is achieved.

Alternatively, the mixture can be processed with a triple roller.

Extrusion pressures will vary with the types of extruders employed, and need only be sufficient to extrude the mixture. The compositions of the invention may be manufactured by continuous as well as batch processes.

As commercially manufactured soap chips and noodles are available world-wide, and are easily obtainable from existing manufacturers, the compositions of the invention can be manufactured economically at most locations. Manufacturers are usually able to supply soap chips or noodles to exact specifications, however, the moisture content can be compensated for by varying the ratio of base to filler in the compositions. As the compositions of the invention can be manufactured in conventional soap making equipment, there is no need for new machinery to be developed.

Interruption of the manufacturing process is not critical as it does not effect the quality or usefulness of the end product. After manufacture, any spills or wastage can simply be recycled without any deleterious effect. The process can be fitted onto the end of almost any "boiled soap" production line eliminating initial capital intensive expenditure. The finished bars or tablets of the soap based insect repellant should be packaged in water vapour impervious material to prevent the bars or tablets drying out where a long shelf life is desired.

Claims

1. An insect repellant soap composition comprising

(d) 0% to 0.3% by weight based on the total weight of the

composition of terpinol;

(f) 0.25% to 2% by weight based on the total weight of the

composition of an insecticide; and

(g) when the filler is full cream milk powder or skim milk powder, 0.05% to 0.3% by weight based on the total weight of the composition of a preservative.

2. A composition as defined in claim 1, comprising 71.9% by weight based on the total weight of the composition of toilet soap base, 7.1% by weight based on the total weight of the composition of a filler, 20% by weight based on the total weight of the composition of an insect repellant, 0.25% by weight based on the total weight of the composition of terpinol, 0.25% by weight based on the total weight of the composition of a binding agent, 0.5% by weight based on the total weight of the composition of an

insecticide, and when the filler is full cream milk powder or skim milk powder, 0.25% by weight based on the total weight of the composition of a preservative.

3. A composition as defined in claim 1 or claim 2, wherein the toilet soap base is a commercial toilet soap based on 85% tallow and 15% coconut oil.

4. A composition as defined in any one of claims 1 to 3, wherein the toilet soap base comprises about 1.2% of a soap of octanoic acid, about 1.1% of a soap of decanoic acid, about 7.2% of a soap of lauric acid, about 4.3% of a soap of myristic acid, about 29.0% of a soap of palmitic acid, about 12.7% of a soap of stearic acid, about 42.1% of a soap of oleic acid, and about 2.6% of a soap of linoleic acid.

5. A composition as defined in any one of claims 1 to 4, wherein the filler is full cream milk powder, skim milk powder or starch.

6. A composition as defined in any one of claims 1 to 5, wherein the insect repellant is N,N-diethyl-3-methylbenzamide (deet), N,N-diethyl- 2-ethoxybenzamide, N,N-dipropyl-2- benzyloxyacetamide, 1-butyl-4-methylcarbostyryl, N,N-dipropyl-1,2- ethoxybenzamide, 2-butyl-2-ethy1-1,3- propanediol, 1,3-bis-butoxymethyl-2- imidazolidone, hexachlorophenol,

1,3-propanediol monobenzoate, diisobutyl malate, ethyl hexanediol, dibutyl phthalate, butyl-3,4-dihydro-2,2- dimethyl-4-oxo-2h-1,3-oxazine,

1,5a,6, 9, 9a,9b- hexahydro-4a-(4H)- dibenzofurancarboxaldehyde,

di-n-propyl-2,5-pyridine- dicarboxylate, and 3-acetyl-2-(2,6-dimethyl- 5-heptenyl)-oxazolidine.

7. A composition as defined in any one of claims 1 to 6, wherein the binding agent is propylene glycol.

8. A composition as defined in any one of claims 1 to 7, wherein the insecticide is a residual insecticide.

9. A composition as defined in claim 8, wherein the insecticide is a synthetic pyrethroid.

10. A composition as defined in claim 9, wherein the insecticide is allethrin [2-methyl-4-oxo-3-(2-propenyl)-2-cyclopent-1-yl-2,2-dimethyl-3- (2-methyl-1-propenyl)-cyclopropanecarboxylate], cyfluthrin [cyano-(3-phenoxy-4-fluorophenyl)-methyl-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate], cyhalothrin [cyano-(3-phenoxyphenyl)-methyl-3-(2-chloro-2-trifluoromethylvinyl)-2,2-dimethylcyclopropanecarboxylate], cypermethrin [cyano-(3-phenoxyphenyl)-methyl-3-(2,2-dichlorovinyl)-2,2-dimethyl cyclopropanecarboxylate], cyphenothrin [cyano-(3-phenoxyphenyl)-methyl-2,2-dimethyl-3-(2-methyl-1-propenyl)-cyclopropanecarboxylate], decamethrin [(lR-[1α(S*),3α])-cyano-(3-phenoxyphenyl)-methyl-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylate], dimethrin [(2,4-dimethylphenyl)-methyl-3-(2,2-dimethylvinyl)-2,2-dimethylcyclopropanecarboxylate], fenvalerate [cyano-(3-phenoxyphenyl)-methyl-4-chloro-α- (1-methyl ethyl)-phenyl acetate], flumethrin [cyano-(3-phenoxy-4-fluorophenyl)-methyl-3-(2-chloro-2-[4-chlorophenyl]vinyl)-2,2-dimethylcyclopropanecarboxylate], permethrin [(3-phenoxyphenyl)-methyl-3-(2,2-dichlorovinyl)2,2-dimethylcyclopropanecarboxylate], phenothrin [(3-phenoxyphenyl)-methyl2,2-dimethyl-3-(2-methyl-1-propenyl)-cyclopropanecarboxylate], resmethrin [(5-benzyl-3-furyl)-methyl-3-(2,2-dimethylvinyl)-2,2-dimethylcyclopropanecarboxylate], tralocythrin [cyano-(3-phenoxyphenyl)-methyl-3-(1,2-dibromo2,2-dichloroethyl)-2,2-dimethylcyclopropanecarboxylate] and tralocythrin

[cyano-(3-phenoxyphenyl)-methyl-3-(1,2,2,2-tetrabromoethyl)-2,2-dimethylcyclopropanecarboxylate].

11. A composition as defined in any one of claims 1 to 10, wherein the preservative is EDTA or a salt thereof.

12. A composition as defined in any one of claims 1 to 11, further comprising an effective amount of an ultra-violet absorbing compound.

13. A process for the manufacture of a composition as defined in any one of claims 1 to 12, which process comprises blending the ingredients of the composition until uniformly distributed, extruding the mixture into its desired shape ant. allowing the shape to harden.

14. A process as defined in claim 13, comprising loading the soap base into a revolving drum which has internal baffles, adding the remaining ingredients other than the filler, mixing until the ingredients are uniformly distributed in the soap base, adding the filler and continuing mixing to achieve uniform distribution, dumping the contents of the drum into a screw feed extruder and cutting the extruded product into bars.

15. A process as defined in claim 14, further comprising re-looping the bars through the extruder one or more times to achieve a more uniform distribution of ingredients.

16. The product of the process of any one of claims 13 to 15.

17. A method for the protection of mammals, especially humans, against insects such as flies and mosquitoes, which method comprises applying to exposed skin of the mammal, an effective amount of a composition as defined in any one of claims 1 to 12.

18. A method of eradicating headlice, which method comprises shampooing the hair with the composition as defined in any one of claims 1 to 12.