EP0735817A4

EP0735817A4 - Slow-release insect-repellent formulations and uses

Info

Publication number: EP0735817A4
Application number: EP95906680A
Authority: EP
Inventors: Raymond J Tucci; Nathan M Dry
Original assignee: Tucci Associates Inc
Current assignee: Tucci Associates Inc
Priority date: 1993-12-23
Filing date: 1994-12-22
Publication date: 1998-09-09
Also published as: WO1995017091A1; EP0735817A1; BR9408411A; NO962652D0; AU1516595A; ZA9410235B; CA2179743A1; AU703959B2; NO962652L; JPH09510184A

Abstract

Slow-release formulations comprising the insect repellent N,N'-diethyl-m-toluamide are disclosed. Also disclosed are fabric substrates which are treated with the formulations of the invention. Methods for preparing the formulations, for treating fabric substrates and for repelling insects using same are disclosed.

Description

SLOW-RELEASE INSECT-REPELLENT FORMULATIONS AND USES

Cross-Reference to Related Application

This is a continuation-in-part of U.S. Application Serial No. 08/173,416 filed December 23, 1993 entitled "SLOW RELEASE INSECT-REPELLENT FORMULATIONS AND USES".

Field of the Invention

The present invention relates to slow-release microcapsular insecticidal formulations comprising the insect repellent N,N' -diethyl-m-toluamide. The invention also relates to woven, non-woven, and knit substrates that are treated with the formulations of the invention.

Background of the Invention

There is a universal need for outdoor fabrics suitable for apparel use and providing for long term insect repellency. Although many insect repellents are effective when applied to the skin as a spray or lotion, their effectiveness is known to decline with time. Furthermore, in order for an insect repellent to be effective, the insect repellent must be applied in a concentrated amount to a small area of the face, neck, and hands or on selected areas of a wearer's garment.

The effectiveness of insect repellents has been known to improve when such repellents are directly applied to fabrics which are suitable for outdoor use, and various techniques have been suggested for providing sustained release of an insect control agent. For example, in U.S. Patent No. 4,056,610 to

Barber, et al . , the invention provides for a microcapsular insecticidal composition comprising a pyrethroid and a biological synergist capable of controlling insects for up to four (4) days.

In U.S. Patent No. 5,198,287 to Samson, the invention provides for a tent fabric coated on the inside with a composition which renders it water repellent, flame retardant and insect repellent using permethrin as the insect repellent. Permethrin is protected against oxygen with a plasticizer. The outside of the tent is coated with a composition which renders it water repellent and flame retardant exclusive of the insect repellent. The insect- repellent composition has an effective life of more than six (6) months.

In U.S. Patent No. 4,765,982 to Ronning, the invention relates to compositions, devices and methods for controlling insect activity wherein an insect control agent is self-adhered to a rough-surfaced fiber and provides extended control of insect activity. The microencapsulated insect control agents disclosed in Barber are named as the preferred insecticide for use in Ronning' s invention. Ronning teaches that smooth-surfaced fibers do not act as good sites for adhesion of microencapsulated insect control agents.

In U.S. Patent No. 5,003,635 to Peterson, the invention relates to elongated flexible insect-repellent strips secured to or retained in cavities in various ar¬ ticles of apparel to repel insects from the person wearing such apparel. In U.S. Patent No. 4,833,006 to McKinney, the invention relates to a coated fabric that is flame resistant and water repellent and includes a polyfunctional isocyanate as an adhesion promoter and binder to adhere the coating to the substrate in a flake proof manner.

In U.S. Patent No. 5,089,298 to McNally, the invention relates to the impregnation of Battle Dress

Uniforms (BDUs) used by the U.S. Military with amylopectin fabric wrinkle inhibitor and permethrin insect/arthropod repellent in combination.

In U.S. Patent No. 3,859,121 to Yeadon et al. , the invention relates to textiles impregnated with insect- repellent compositions including piperonyl butoxide and pyrethrin, wetting agent, thickener and an agent for preventing migration of the pyrethrin and piperonyl butoxide repellent into foods stored in contact with the textiles and for otherwise retaining the repellent in the textiles.

This invention provides for fabric substrates treated with formulations which comprise an insect repellent such as for example N,N' -diethyl-m-toluamide (DEET) which is known to effectively control a variety of insects. In addition to being an effective insect repellent, DEET is environmentally safe and leaves no harmful residues. DEET has been found to be stable at both reduced and elevated temperatures and under storage conditions. DEET is effective on biting flies, chiggers, deerflies, fleas, leeches, mosquitoes, and ticks. Several factors influence the efficacy of DEET as an insect repellent, such as, for example, extreme environmental conditions, the extent of absorption and elimination, the type of repellent formulation, and the avidity of the test species. The efficacy of DEET is reduced by increased perspiration rate and the duration of repellent activity is influenced by wash-off, abrasion from the treated surface and absorption. Water, from either rainfall or perspiration, decreases the efficacy of DEET.

Summary of the Invention

It is a primary object of this invention to provide for a slow-release insect-repellent formulation and process of making same comprising an insect-repellent entrapped in a carbohydrate matrix such that the insect repellent is slowly released from the matrix. The insect repellent is comprised in microcapsules with a diameter of from about 0.005 mm to about 1.800 mm.

It is a further object of this invention to provide for slow-release insect-repellent formulations and process of making same suitable for treating woven, non- woven and knit substrates .

It is yet another object of this invention to provide for a process for treating a fabric substrate with the insect-repellent formulations of this invention.

It is yet a further object of this invention to provide for a process for repelling insects with the insect- repellent formulations of this invention.

It is another object of this invention to provide for fabric substrates treated with the formulations of this invention with an insect repellency of up to twelve months and a stability comparable to that of consumer apparel. It is another object of this invention to provide for garments manufactured with the fabric substrates of this invention.

Other objects will appear hereinafter.

Detailed Description of the Preferred Embodiments

Oleophilic silicone compounds, heavy alcohols

(such as for example polyvinyl alcohol, airvol, polyvinyl acetate, liquefied synthetic rubber or acrylic copolymers) and the insect repellent N,N' -diethyl-m-toluamide (DEET) can be together formulated and spray-dried to form mi- crocapsules in powder form. The formulation has novel properties in that the microencapsulated DEET can be time- released and the rate of release of the DEET can be con¬ trolled by varying the amounts of heavy alcohol or plas- ticizers used in the process. The DEET can time-release over a period of time spanning of from about 24 hours to about several months and is affected by the method of storage of the powder and exposure to light and air. It is believed that the time-release of DEET can be attributed to the entrapment of the DEET in the resulting structure of the capsule-forming compounds and the entrapping effect of the silicone elastomers. The time-release property of the DEET and the overall stability of the powder can be affected by further coating the microcapsule with for example a wax compound (bee wax, gelatin or polyethylene glycol and derivatives) for an intermediate coating or with for example a ceramic compound (clay, slip, china or ivory) for a harder coating or a protective layer. Other novel properties of the microcapsules and the powder include solubility in water and water-based compounds (such as for example lotions, cremes, latex paints, acrylic-based paints and sealers) as well as its solubility in oil, hydrocarbon solvents and the like. It is to be noted that before formulation, all compounds entering into the formulation including DEET were insoluble in water.

The insect-repellent formulations of the invention can be applied to a wide range of fabric substrates without being limited by the coarseness or smoothness of the fabric substrate. As volatility is one of the functional attributes associated with insect repellency, and a high volatility lowers the long term effectiveness of the insect repellent, this invention provides for an insect-repellent formulation which lowers the volatility of the insect repellent thus prolonging its effectiveness.

Furthermore, the insect-repellent formulations of the invention can be combined with a wide range of fabric treatment formulations. The resulting formulations can be applied to any suitable fabric substrate depending on the intended use of the fabric and the fabric treatment process such as, for example, cottons, knits, polyesters or blends, fiberglass, wovens or non-wovens and heat-sensitive substrates such as acetates and mode-acrylates and nylon. In order to lower the insect-repellent volatility and control the loss of insect-repellent activity, the formulations can be applied such that multiple layers of super thin laminates are produced and the insect repellent is thus slowly released at each laminate interface as it ruptures. The slow-release insect-repellent formulation of the invention can be prepared by first formulating the insect repellent N,N' -diethyl-m-toluamide with an oleophilic chemical such as a silicone compound such as for example elastomeric or monomeric silicone, and then by mechanical/ and or chemical entrapment of the resulting compound in a carbohydrate matrix, such as for example a starch compound including but not limited to corn starch, potato starch, technical starch, rice starch and any of the synthetic starches. Silicone, which is immiscible with water, is dissolved with the DEET which is also immiscible with water. The DEET-silicone solution is mixed into a starch solution with the resulting solution being miscible in water. The DEET molecule is entrapped in the lattice-like structure of the starch molecule which has the effect of lowering the vapor pressure of the insect repellent thus reducing its volatility. The DEET is slowly released from the lattice¬ like structure of the starch molecule with the net effect of the formation of a slow-release insect-repellent formulation.

In a preferred embodiment, the slow-release insect-repellent formulation consists of from about 40% to about 75% starch, and of from about 10% to about 35% N,N'- diethyl-m-toluamide, and of from about 15% to about 25% silicone, preferably about 65% starch, about 15% N,N'- diethyl-m-toluamide and about 20% silicone on a dry weight basis. Following spray-drying, the slow-release insect- repellent microcapsules have a particle size of from about 0.005 mm to about 1.800 mm. The slow-release insect-repellent formulation of the invention is prepared by first dissolving starch in water at its boiling point. The starch solution is cooled to room temperature by further addition of water and the insecticide N,N' -diethyl-m-toluamide and silicone are slurried into the starch solution. Following slurrying, the formulation is spray dried using conventional spray drying equipment such that the slurry produces a fine white powder comprising DEET of from about 8% to about 11% and with a moisture of from about 3% to about 8%, total solids of from about 10% to about 15% and little or no odor.

The resultant slow-release insect-repellent formulations of the invention are a non-irritant to the skin or mucous membranes and are nontoxic. As the following embodiments describe, the slow-release insect-repellent formulation of the invention can be formulated for application on fabric substrate in high yields without affecting the functionality, esthetic appearance, hand or feel of the treated substrate and without leaving any residual odor.

In a preferred embodiment, the slow-release insect-repellent formulation can be combined with a cationic softener and applied as a finishing rinse to a fabric substrate that has been already dyed. The slow-release insect-repellent formulation can be combined into a formulation comprising of from about 2% to about 10% on the weight of the fabric (owf) of the slow-release insect- repellent formulation and of from about 2% to about 6% (owf) cationic softener. This formulation can be exhausted onto the fabric substrate under mildly acidic conditions, for example using acetic acid such that the pH is of from about 5.50 to about 6.60 with the slow-release insect-repellent formulation adhering to the cationic sites in dyeing and the cationic softener adhering to the fabric substrate. In another preferred embodiment, the slow-release insect-repellent formulation composition can be combined in a formulation comprising of from about 90% to about 98%

(owf) of a padding formulation and of from about 2% to about 10% (owf) of the slow-release insect-repellent formulation.

In another preferred embodiment, the slow-release insect-repellent formulation can be combined in a formulation comprising of from about 90% to about 98% (owf) of a pigment printing paste formulation and of from about 2% to about 10% (owf) of the slow-release insect-repellent formulation. The slow-release insect-repellent formulation cross-links with the pigment binder during pigment dyeing and printing to link on to the cellulose groups of the fabric substrate.

In another preferred embodiment, the slow-release insect-repellent formulation can be combined in a formulation comprising of from about 90% to about 98% (owf) of water repellent formulation and of from about 2% to about 10% (owf) of the slow-release insect-repellent formulation.

In another preferred embodiment, the slow-release insect-repellent formulation can be used in a final rinse formulation. Fabric substrates after dyeing, pigment padding and printing, with the appropriate formulation which comprises the slow-release insect-repellent formulation of the invention, can be given a resin finish for hand, appearance and dimensional stability. In this particular embodiment, the resin finish acts as a super thin laminate and provides the treated fabric with an insect-repellent finish and more particularly when the resin used is urea- formaldehyde by the cross-linking of the molecular structure of the cotton fiber to the cellulose fiber during resin curing conditions. The slow-release insect-repellent formulation is trapped during the reaction of the urea- formaldehyde with the cellulose molecule in the cotton fabric. In a preferred embodiment, substrate fabrics of 100% cotton and a 50/50 polyester/cotton blend can be treated with a resin finish comprising of from about 2% to about 5% (owf) of the slow-release insect-repellent formulation of the invention and of about 95% to about 98% (owf) of a resin finish formulation.

In another preferred embodiment, the slow-release insect-repellent formulation can be used in heat transfer printing using a wide range of substrate fabrics. In a preferred embodiment, of from about 2% to about 10% weight/ weight (w/w) of the slow-release insect-repellent formulation can be combined with of from about 2% to about

5% (w/w) ink dispersion and with from about 85% to about 96%

(w/w) extender. The fabric was processed by heat transfer printing, i.e., by vaporization of the dye from the paper to the fabric at the sublimation temperature of the dye. In another embodiment, the ink dispersion can omitted and 100% (w/w) extender can be used. In both cases, the adhesion of the heat transfer paper to the fabric prevents the insect repellent from volatilizing and escaping resulting in greater durability.

From about 2% to about 10% (w/w) of the slow- release insect-repellent formulation of Example I can be combined with about 100% extender. The fabric was processed by heat transfer printing, i.e., by vaporization of the dye from the paper to the fabric at the sublimation temperature of the dye. Example I

In this example, an insect-repellent formulation can be prepared by mixing into a starch slurry a mixture of silicone about 4% (w/w) and the insect-repellent N,N'- diethyl-m-toluamide about 8% (w/w) . The starch slurry is formed by dissolving about 8% (w/w) starch into about 80% (w/w) water at its boiling point. The mixture of insect repellent and silicone is added to the starch mixture after cooling the slurry to room temperature.

The resultant slurry is spray dried in a spray drying chamber at an inlet temperature of about 230°F using an atomizing force of from about 2400 to about 3200 psig from a cocurrant atomizer. The slurry produces a fine white powder comprising of from about 0.1% to about 25% DEET and with about 5% moisture and about 15% total solids.

Example II

From about 2% to about 10% (owf) of the slow- release insect-repellent formulation of Example I can be combined with about 2% (owf) cationic softener (for example, Alpha Soft GMR from Alpha Chemical) and exhausted on a fabric substrate that has been dyed on a jigg, beck or jet at about 120°F, for about fifteen (15) minutes and at a pH of from about 5.50 to about 6.60, adjusted with acetic acid.

Example III

From about 2% to about 10% (owf) of the slow- release insect-repellent formulation of Example I can be combined with a pigment padding formulation of about 0.06% (owf) aqueous ammonia, about 4.78% (owf) padding emulsion (for example, padding emulsion #8908 from BASF) , about 2.39% (owf) antimigrant (for example, antimigrant #09-99515 from BASF) , about 0.48% (owf) ammonium sulphate, water, and a variable weight percent of a pigment dye depending on the shade. The resulting formulation is padded on to the fabric at from about 85% to about 90% wet pick up, dried at about 275°F and cured at about 340°F for about thirty (30) seconds.

Example IV

From about 2% to about 10% (owf) of the slow- release insect-repellent formulation of Example I can be combined with a pigment printing formulation of about 4.7%

(owf) of a dispersion of an acrylic copolymer in mineral oil

(for example, Allied DP3-5205 from Allied Colloids, Inc.) , about 10% (owf) white aqueous-based acrylate copolymer emulsion (for example, Allied PB-8A from Allied Colloids,

Inc.), about 83.3% (owf) water, and a variable weight percent of a pigment print dye depending on the shade. The resulting formulation is printed onto the fabric in all colors of the pattern and cured at about 340°F for about sixty (60) seconds.

Example V

From about 2% to about 10% (owf) of the slow- release insect-repellent formulation of Example I can be combined with a water repellent formulation of about 3.6% (owf) silicone softener (for example, Alpha Chem. SW-1 from Alpha Chem) , about 6% (owf) wax emulsion (for example, fluoropolymer wax emulsion PEL-TEK 508, Hydrolabs, Inc.) , and about 7.2% (owf) of a glyoxal reactant (for example, REACTEX #7222 from Ivax Industries, Inc.) . The resulting formulation is padded onto the fabric at about 85% to about

90% (owf) wet-pickup, dried at about 275°F and cured at about 340°F for about twenty (20) seconds. Example VI

From about 2% to about 10% (owf) of the slow- release insect-repellent formulation of Example I can be combined with a resin finishing composition suitable for treating 100% cotton and comprising about 3.6% (owf) cationic softener, about 1.2% (owf) silicone softener, and about 9.6% (owf) glyoxal reactant.

From about 2% to about 10% (owf) of the slow- release insect-repellent formulation of Example I can also be combined with a resin finishing composition suitable for treating 50/50 polyester/cotton and 'comprising about 3.6% cationic softener, about 1.2% (owf) silicone softener, and about 2.4% (owf) glyoxal reactant.

The resin finishing formulation can be applied to a fabric substrate that has been dyed, pigment padded, and/or printed as in the above Examples. The resin finish acts as a super thin laminate and provides an additional insect-repellent coating.

With both formulas and fabrics, the chemical mixture is padded on at from about 85% to about 90% wet pickup, dried at about 275°F and cured at about 340° for twenty (20) seconds.

Example VII

From about 2% to about 10% (w/w) of the slow- release insect-repellent formulation of Example I can be combined with about 2% ink dispersion and about 85% ex¬ tender. The fabric was processed by heat transfer printing, i.e., by vaporization of the dye from the paper to the fabric at the sublimation temperature of the dye. Example VIII

From about 2% to about 10% (w/w) of the slow- release insect-repellent formulation of Example I can be combined with about 100% extender. The fabric was processed by heat transfer printing, i.e., by vaporization of the dye from the paper to the fabric at the sublimation temperature of the dye.

Field Testing

The slow-release insect-repellent formulations of the invention were found to afford the wearer complete protection under all types of weather and infestation conditions. Furthermore, the insect-repellency effectiveness of the fabric substrate treatment was found to span up to a period of about several hours to about twelve (12) months.

To test the stability of the fabric treatment, garments were produced from treated fabric. Fabric sub¬ strates which were laundered from ten (10) to fifty (50) launderings continue to exhibit insect-repellent properties. It is to be noted that the industry standard number of washings for apparel is three (3) , five (5) , or ten (10) for consumer apparel and fifty (50) washings for military or certain specialty requirements such as, for example, flame retardancy.

To test the effectiveness of the treatment, laboratory size knit and woven fabric samples were processed using the formulations described above. A first batch of the samples were tested for direct insect repellency using fireants and fruit flies as test insects . For several hours the fireants and fruit flies were directly repelled by the fabric samples. A second batch of the fabric samples were tested by wearers who wore shirts made from the fabric sample. Mosquitoes and blackflies were repelled for at least eleven (11) hours during a fishing trip.

A production trial was initiated on four (4) fabric substrates, knit and woven cotton, poly/cotton and poly/nylon. The fabrics were dyed with the slow-release insect-repellent formulation applied during dyeing or resin finishing as one type of group of fabrics. Another group of knitted and woven fabrics were pad dyed, printed and resin finished with the slow-release insect-repellent formulation applied at the dyeing, printing and resin finishing steps.

Garments such as shirts, hats, and the like were produced from the treated fabric substrates. The garments were tested under conditions encountered during outdoor activities. The garments were found to repel insects under outdoor conditions during activities such as hiking, hunting, and fishing in coastal, piedmont and mountain conditions during day and night wear. The treated garments were compared to untreated counterparts under the same conditions. In one particular field trial, garments were tested on mosquitoes. The mosquitoes would land on exposed skin and promptly bite. By contrast, when the mosquitoes landed on the treated fabric at any location on the garment, they would only remain for about four (4) to about six (6) seconds before taking off .

This invention and many of ^* its attendant ad¬ vantages will be understood from the foregoing description, and it will be apparent that various modifications and changes can be made without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the process hereinbefore described being merely preferred embodiments . For example, the slow-release insect-repellent formulation of the invention can incorporate different insect control agents such as, for example, permethrin and more generally alkylamides and alkylneodecamides. Ad- ditionally, the slow-release insect-repellent formulation can be applied on a wide range of fabric substrates in¬ cluding but not limited to textile blends, woven and non- woven, knits, fibers, leather and synthetic adaptations of leather, flocked fabrics, wood and wood derivatives, plastic and laminates, cable, sheeting, film fiberglass and plexiglass. The slow-release insect-repellent formulation can be also be comprised in moth proofing formulation, packaging material, and paint formulations. Furthermore, with hard covered capsules, a longer-term repellency can e obtained when such capsules are used in the manufacture of commercial finishes such as caulking formulations, paint sealers, wall and floor coverings and the like. Additionally, the formulations of the invention can have a wide applicability in situations requiring a lower concentration of DEET. As an example, the slow-release insect-repellent formulation can be incorporated with a scent or a fragrance or pheromones or with any other formulations that could be conducive to applications in sporting, farming, or hunting situations. Conversely, higher concentrations of up to from about 20% to about 25% solids of the repellent can be used in caulking compounds.

The present invention may be embodied in other specific forms without departing from its spirit or es¬ sential attributes. Accordingly, reference should be made to the appended claims, rather than the foregoing speci¬ fication, as indicating the scope of the invention.

Claims

We claim :

1. A slow-release insect-repellent formulation suitable for treating woven, nonwoven and knit substrates, said formulation comprising an insect repellent, an oleophilic chemical soluble in said insect repellent, a carbohydrate matrix wherein the combination of said insect repellent and oleophilic chemical is entrapped in said matrix such that said insect repellent is slowly released from said matrix.

2. The formulation of claim 1 wherein the weight ratio of said insect repellent to said oleophilic chemical is of from about 0.13:0.2 to about 0.875:0.635 per weight of said carbohydrate matrix.

3. The formulation of claim 2 wherein said insect repellent is comprised in microcapsules with a diameter of from about 0.005 mm to about 1.800 mm and wherein said insect repellent is of from about 3% to about 8% on a weight basis with said microcapsules.

. The formulation of claim 3 further comprising a fabric treatment formulation.

5. The formulation of claim 4 wherein said fabric treatment formulation comprises of from about 2% to about 6% (owf) cationic softener.

6. The formulation of claim 4 wherein said fabric treatment formulation is a padding formulation of from about

90% to about 98% (owf) .

7. The formulation of claim 4 wherein said fabric treatment formulation is a pigment printing paste formulation of from about 90% to about 98% (owf) . 8. The formulation of claim 4 wherein said fabric treatment formulation is a water repellent formulation of from about 90% to about 98% (owf) .

9. The formulation of claim 4 wherein said f bric treatment formulation is a finishing rinse formulation of from about 2% to about 5% (owf) .

10. The formulation of claim 4 wherein said fabric treatment formulation is an ink formulation comprising of from about 2% to about 5% (w/w) ink dispersion and from about 85% to about 96% (w/w) extender.

11. The formulation of claim 4 wherein said fabric treatment formulation comprises about 100% (w/w) extender.

12. The formulation of claim 4 wherein said insect repellent is N,N' -diethyl-m-toluamide.

13. A process for the manufacture of an insect- repellent formulation comprising the steps of combining an insect repellent with an oleophilic chemical soluble in said insect repellent; slurrying said combination in a water solution comprising said carbohydrate matrix such that said combination is entrapped in said matrix and slowly released from said matrix; and spray drying said slurry to form a powder comprising microcapsules of said insect repellent .

14. The process of claim 13 wherein the weight ratio of said insect repellent to said oleophilic chemical is of from about 0.13:0.2 to about 0.875:0.635 on a weight basis with said carbohydrate matrix.

15. The process of claim 14 wherein said mi¬ crocapsules are of from about 0.005 mm to about 1.800 mm in diameter and wherein said insect repellent is of from about 3% to about 8% on a weight basis with said microcapsules. 16. The process of claim 15 which further comprises the step of combining with said powder a fabric treatment formulation.

17. The process of claim 16 wherein said fabric treatment formulation comprises of from about 2% to about 6%

(owf) cationic softener.

18. The process of claim 16 wherein said f bric treatment formulation is a padding formulation of from about 90% to about 98% (owf) .

19. The process of claim 16 wherein said fabric treatment formulation is a pigment printing paste formu¬ lation of from about 90% to about 98% (owf) .

20. The process of claim 16 wherein said fabric treatment formulation is a water repellent formulation of from about 90% to about 98% (owf) .

21. The process of claim 16 wherein said fabric treatment formulation is a finishing rinse formulation of from about 2% to about 5% (owf) .

22. The process of claim 16 wherein said fabric treatment formulation is an ink formulation comprising of from about 2% to about 5% (w/w) ink dispersion and from about 85% to about 96% (w/w) extender.

23. The process of claim 16 wherein said fabric treatment formulation comprises about 100% (w/w) extender.

2 . The process of claim 16 wherein said insect repellent is N,N' -diethyl-m-toluamide. 25. A process for treating a fabric substrate comprising the step of applying onto said fabric substrate an insect-repellent formulation comprised of a fabric treatment formulation in combination with an insect- repellent composition comprising an insect repellent, an oleophilic chemical soluble in said insect repellent, a carbohydrate matrix wherein the combination of said insect repellent and said oleophilic chemical is entrapped in said matrix such that said insect repellent is slowly released from said matrix.

26. The process of claim 25 wherein the weight ratio of said insect repellent to said oleophilic chemical is of from about 0.13:0.2 to about 0.875:0.635 per weight of said carbohydrate matrix.

27. The process of claim 26 wherein said insect repellent is comprised in microcapsules with a diameter of from about 0.005 mm to about 1.800 mm and wherein said insect repellent is of from about 3% to about 8% on a weight basis with said microcapsules.

28. The process of claim 27 wherein said fabric treatment formulation comprises of from about 2% to about 6% (owf) cationic softener.

29. The process of claim 27 wherein said fabric treatment formulation is a padding formulation of from about 90% to about 98% (owf) .

30. The process of claim 27 wherein said fabric treatment formulation is a pigment printing paste formulation of from about 90% to about 98% (owf) .

31. The process of claim 27 wherein said fabric treatment formulation is a water repellent formulation of from about 90% to about 98% (owf) . 32. The process of claim 27 wherein said fabric treatment formulation is a finishing rinse formulation of from about 2% to about 5% (owf) .

33. The process of claim 27 wherein said fabric treatment formulation is an ink formulation comprising of from about 2% to about 5% (w/w) ink dispersion and from about 85% to about 96% (w/w) extender.

34. The process of claim 27 wherein said fabric treatment formulation comprises about 100% (w/w) extender.

35. The process of claim 27 wherein said insect repellent is N,N' -diethyl-m-toluamide.

36. A process for repelling insects comprising the step of contacting said insects with an insect-repellent formulation comprising an insect-repellent composition comprised of an insect repellent, an oleophilic chemical soluble in said insect repellent, a carbohydrate matrix wherein the combination of said insect repellent and said oleophilic chemical is entrapped in said matrix such that said insect repellent is slowly released from said matrix.

37. The process of claim 36 wherein the weight ratio of said insect repellent to said oleophilic chemical is of from about 0.13:0.2 to about 0.875:0.635 per weight of said carbohydrate matrix.

38. The process of claim 37 wherein said insect repellent is comprised in microcapsules with a diameter of from about 0.005 mm to about 1.800 mm and wherein said insect repellent is of from about 3% to 8% on a weight basis with said microcapsules. 39. The process of claim 38 which further comprises the step of combining with said powder a fabric treatment formulation.

40. The process of claim 39 wherein said fabric treatment formulation comprises of from about 2% to about 6%

(owf) cationic softener.

41. The process of claim 39 wherein said fabric treatment formulation is a padding formulation of from about 90% to about 98% (owf) .

42. The process of claim 39 wherein said fabric treatment formulation is a pigment printing paste formulation of from about 90% to about 98% (owf) .

43. The process of claim 39 wherein said fabric treatment formulation is a water repellent formulation of from about 90% to about 98% (owf) .

44. The process of claim 39 wherein said fabric treatment formulation is a finishing rinse formulation of from about 2% to about 5% (owf) .

45. The process of claim 39 wherein said fabric treatment formulation is an ink formulation comprising of from about 2% to about 5% (w/w) ink dispersion and from about 85% to about 96% (w/w) extender.

46. The process of claim 39 wherein said fabric treatment formulation comprises about 100% (w/w) extender.

47. The process of claim 39 wherein said insect repellent is N,N' -diethyl-m-toluamide. 48. A fabric substrate comprising the slow- release insect repellent formulation of claim 1, said fabric substrate having an insect repellency of up to twelve (12) months and a stability comparable to that of consumer apparel.

49. The fabric substrate 48 wherein the weight ratio of said insect repellent to said oleophilic chemical is of from about 0.13:0.2 to about 0.875:0.635 per weight of said carbohydrate matrix.

50. The fabric substrate of claim 49 wherein said insect repellent is comprised in microcapsules with a diameter of from about 0.005 mm to about 1.800 mm and wherein said insect repellent is of from about 3% to about 8% on a weight basis with said microcapsules.

51. The fabric substrate of claim 50 wherein said insect repellent is N,N' -diethyl-m-toluamide.

52. A garment manufactured with the fabric substrate of claim 48.