the fabric or textile substrate to be treated in accordance with the invention is not limited as to type . thus cotton , rayon , linen , polyester , natural and synthetic polyamides (“ nylons ”), acrylic , cellulose acetate , polyaramide , polypropylene fabric , blends of these , for example , cotton and polyester , cotton and nylon , are suitable fabrics in the context of the invention . leather , both natural and man - made , are also contemplated as a garment material suitable for insecticidal impregnation according to the invention . in a preferred embodiment of the invention the fabric is a polyester fabric . in another preferred embodiment the fabric is a nylon or a nylon blend . in a further preferred embodiment , the fabrics are based on polyaramides such as poly meta - aramid and poly para - aramid . other fibers and fabrics of interest include fr rayon ( such as lenzing fr ) and pbi ( polybenzimidazole ). according to federal government guidelines , the target add - on for permethrin on the fabric is 1 . 25 grams / meter 2 , having been determined by the national research council that at this level , a soldier wearing permethrin - impregnated bdu for upwards of 18 hours a day , seven days week for several ( 10 ) years was unlikely to experience adverse health effects , and that the risk to garment workers handling fabric impregnated at this rate was even less . before a given fabric can be treated in accordance with the present invention , it is necessary to calculate the proper concentration of insecticide , e . g ., permethrin , present in an aqueous impregnating bath such as a pad mix . that calculation is dependent on the following parameters : b ) target permethrin ( in grams / m 2 )( set at 1 . 25 g / m 2 ); d ) percent available permethrin in the commercial formulation being used ( set by the manufacturer of the insecticide ). parameters 1 , 2 , and 4 are rather straight forward to determine ; the information for determining their respective values is either provided ( e . g ., by the manufacturer ) or is easily ascertained by weighing and measuring the fabric to be treated . for parameter a , the “ fabric weight ” is typically expressed in the us textile market / industry as “ ounces / linear yard ”; therefore it will be necessary to convert those units to grams / m 2 using standard conversion factors in order to plug the values into the permethrin calculation below . the percent wet pick - up of a given fabric ( variable “ c ”) to be insecticidally treated is defined according to the following formula : wherein the dry weight is obtained by weighing a piece of the fabric to be treated and recording its weight , and the wet weight is obtained by soaking the same piece of fabric in water until thoroughly wet , running the soaked fabric through a pad squeeze roll which duplicates production squeeze pressures , reweighing and recording that weight . the calculation for the quantity of permethrin ( expressed as a percentage of the aqueous pad mix ) is as follows : wherein a , b , c , and d are defined above . the “% permethrin ” is of the active only , to clarify from , for example , the commercial preparation ( evercide ® permethrin 40 % manufacturing concentrate 2778 — manufactured by mclaughlin gormley king co . in minneapolis minn .) which is 40 % permethrin in composition . it is a routine calculation to ascertain how much of a commercial insecticidal preparation to add to the aqueous pad mix once the % active is determined from the above formula . thus for any given type of fabric to be treated in accordance with the method of the invention , the textile worker is able to determine precisely and without undue experimentation , the desired fabric add - on . for the sake of example only , the following ranges serve as a rough guide for the values of permethrin to be added to the pad bath . the ranges however were determined using the above calculations and based on the following assumptions about the particular fabric to be treated , namely , 1 ) treating a 60 inch width fabric having 2 ) 100 % wet pick = up . thus , a fabric with a fabric yield ( or weight ) of from 1 to 4 ounces per square yard ( 1 - 4 oz / yd 2 ) and further characterized by assumptions 1 ) and 2 ), would require a pad bath that is from 2 to 9 % permethrin based on the weight of the bath size . in another scenario , a fabric with a fabric yield ( or weight ) of from 5 to 10 ounces per square yard ( 5 - 10 oz / yd 2 ) and further characterized by assumptions 1 ) and 2 ), would require a pad bath that is from 1 to 2 % permethrin based on the weight of the bath size . in another scenario , a fabric with a fabric weight of from 5 to 10 ounces per square yard ( 5 - 10 oz / yd 2 ) and further characterized by assumptions 1 ) and 2 ), would require a pad bath that is from 1 to 2 % permethrin based on the weight of the bath size . for fabrics weighing 11 oz ./ yd 2 or heavier , under the stated assumptions , one would add less than 1 % permethrin based on the weight of the bath size . once again , to satisfy the enablement requirement of the present disclosure , the amount of insecticide to be added to the bath to achieve the desired fabric add - on , is determined based on the properties ( weight , width , % wet pick - up ) of the fabric , the % available insecticide in the insecticidal formulation , using the stated calculation . the ranges set forth above are merely shown to provide a general idea of how much permethrin formulation ( e . g ., evercide ®) on a weight percentage basis needs to be added to a pad bath for fabrics of various weights and specified width and pick - up . the method of incorporating the insecticide into the fabric is by impregnation or by exhaust methods . thus application by conventional impregnation methods such as dipping , padding or spray processes are within the scope of the invention , as are conventional exhaust processes using one or more of long or short liquor ratios ( e . g . liquor - to - goods ratios of from 100 : 1 to 0 . 5 : 1 ), optimizing ( i . e ., raising ) the temperature of the aqueous bath , and mildly acidifying the bath conditions . in a preferred embodiment of the invention permethrin is impregnated into the fabric substrate by padding , using a pad bath at ambient temperature . the wash durability of the insecticide impregnated in the fabric is improved by adding a retention additive or polymer binder to the pad mix or bath that also contains the insecticide . the term “ retention additive ” is used to designate a compound that is not a known polymer binder , but rather a compound with a different function but that in the context of the invention , is effective to improve the wash durability of the insecticide . depending upon the type of fabric to be insecticidally treated , the type of additive or binder varies in accordance with the invention . as previously stated , fabrics such as cotton , rayon , linen , polyester , natural and synthetic polyamides (“ nylons ”), acrylic , cellulose acetate , polyaramide , polypropylene fabric , and blends of these ( e . g ., cotton and polyester , cotton and nylon ) are suitable for treatment in accordance with the invention . particularly preferred fabrics are polyester and woven nylons . in the case of nylon fabrics , the additive that improves the wash durability of the permethrin is either a water - soluble nylon - based polymer , a polyurethane binder or a dye fixative agent . water - soluble , nylon - based polymers suitable in the practice of the invention are typically referred to as polyetheramide polymers . these polymers arose as an improvement to traditional nylon polymers , e . g ., by replacing the alkylene diamine reactant ( typically reacted with a dicarboxylic acid such as adipic acid as in the formation of nylon 6 , 6 ) with an alkylene glycol diamine . in general , polyetheramide polymers can be formed by reacting polycarboxylic acids with polyetheramines . alternatively , these polymers can be formed by copolymerizing caprolactam with , e . g ., polyethyleneoxy diamines and a dibasic acid such as terephthalic acid . polyetheramide polymers and block polymers and methods for their preparation are known in the art . see , for example , u . s . pat . nos . 3 , 454 , 534 , 4 , 919 , 997 , 5 , 166 , 309 ( block polyetheramides ), and 5 , 342 , 918 ( carboxyl - terminated polyetheramides ); french patent publication nos . 2 , 273 , 021 , 2 , 384 , 810 , and 2 , 401 , 947 ; german publication de 3 , 428 , 405 discloses polyetheramides prepared from a stoichiometric mixture of oligoamidediacid and of oligoetherdiol , and from 3 - 30 % relative to the mixture of diol of low molecular weight ; japanese publications j63 - 048 , 332 , j63 - 227 , 238 , j63 - 280 , 736 , j63 - 105 , 032 , and j63 - 182 , 343 describe block polyetheramides and processes for their preparation . more particularly , suitable polyetheramide polymers in the practice of the invention include copolymers of a polyalkyleneglycol and a poly ( c 3 - c 12 ) alkyllactam . in a more preferred embodiment of the invention , copolymers of peg / polycaprolactam polymer and peg / polylauryllactam polymer are employed to bring about the improved wash durability of the insecticidally treated fabric . the polyurethane binder of the invention is typically a polyurethane dispersion . the term polyurethane dispersion as used herein describes stable mixtures of polyurethane polymers in water . methods of preparing polyurethane dispersions are well known in the art and many of polyurethane dispersions are commercially available . polyurethane polymers are generally characterized by their monomer content and most commonly involve the reaction of a diisocyanate with a polyol and chain extender . while the present inventors believe the polyurethane dispersion can be a stable aqueous mixture of any known polyurethane , typically the polyurethanes suitable for the use in the aqueous polyurethane dispersions are the reaction products ( a ) an isocyanate compound having at least two isocyanate (— nco ) functionalities per molecule ; ( b ) a polyol having at least two hydroxy functionalities per molecule and a molecular weight ranging from 250 to 10 , 000 g / mole . the polyol may be selected from those commonly found in polyurethane manufacturing such as hydroxy - containing or terminated polyethers , polyesters , polycarbonates , polycaprolactones , polythioethers , polyetheresters , polyolefins , and polydienes . suitable polyether polyols for the preparation of polyether polyurethanes and their dispersions include the polymerization products of cyclic oxides such as ethylene oxide , propylene oxide , tetrahydrofuran , or mixtures thereof . polyether polyols commonly found include polyoxyethylene ( peo ) polyols , plyoxypropylene ( ppo ) polyols , polyoxytetramethylene ( ptmo ) polyols , and polyols derived from the mixture of cyclic oxides such as poly ( oxyethylene - co - polypropylene ) polyols . typical molecular weight of polyether polyols can range from 250 to 10 , 000 g / mole . suitable polyester polyols for the preparation of polyester polyurethanes and their aqueous dispersions include ; hydroxy - terminated or containing reaction products of ethylene glycol , propylene glycol , diethylene glycol , neopentyl glycol , 1 - 4 , butanediol , furan dimethanol , polyether diols , or mixtures thereof , with dicarboxylic acids or their ester - forming derivatives . modified polyether polyurethanes such as polyetherester polyurethanes and polyethercarbonate polyurethanes may also be suitable polyurethanes for the preparation of aqueous polyurethane dispersions . these modified polyether polyurethanes can be derived by incorporating additional polyester polyols or polycarbonate polyols into polyether polyols during the polyurethane manufacturing . typically the polyurethane polymer useful to prepare the polyurethane dispersion as component in the compositions of the present invention is selected from polyether polyurethanes , polyester polyurethanes , polycarbonate polyurethanes , polyetherester polyurethanes , polyethercarbonate polyurethanes , polycaprolactone polyurethanes , hydrocarbon polyurethanes , aliphatic polyurethanes , aromatic polyurethanes , and combinations thereof . polyurethane dispersion as used herein encompasses both conventional emulsions of polyurethane polymers , for example where a preformed polyurethane polymer is emulsified into an aqueous medium with the addition of surfactants and application of shear , and also includes stable mixtures of self - dispersing polyurethane polymers . polyurethane dispersions of self - dispersing polyurethane polymers are well known in the art and many are commercially available . these polyurethane dispersions are generally free of external surfactants because chemical moieties having surfactant like characteristics have been incorporated into the polyurethane polymer and therefore are “ self emulsifying ” or “ self dispersing ”. representative examples of internal emulsifier moieties that can be incorporated into the polyurethane dispersions useful in the present invention include ; ionic groups such as sulfontates , carboxylates , and quaternary amines ; as well as nonionic emulsifier groups such as polyethers . such polyurethane dispersions are well known in the art , and are typically prepared by either a one stage or two - stage process . typically , a isocyanate - terminated polyurethane prepolymer is made from isocyanates , polyols , optional chain extender , and at least one monomer containing a hydrophilic group to render the prepolymer water dispersible . the polyurethane dispersion can then be prepared by dispersing the isocyanate - terminated polyurethane prepolymer in water with other polyisocyanates . further chain extension can be affected by the addition of chain extenders to the aqueous dispersion . depending on the choice of the hydrophilic group used to render the polyurethane polymer water dispersible , an additional reaction step may be needed to convert the hydrophilic group to an ionic species , for example converting a carboxyl group to an ionic salt or an amine to an amine salt or cationic quaternary group . representative , non - limiting examples of polyurethane dispersions that are suitable for use as the binder component in the compositions of the present invention , as well as general descriptions of techniques useful to prepare polyurethane dispersions can be found in u . s . pat . nos . 4 , 829 , 122 , 4 , 921 , 842 , 5 , 025 , 064 , 5 , 055 , 516 , 5 , 308 , 914 , 5 , 334 , 690 , 5 , 342 , 915 , 5 , 717 , 024 5 , 733 , 967 , 6 , 017 , 998 , 6 , 077 , 611 , 6 , 147 , 155 , and 6 , 239 , 213 . representative , non - limiting examples of commercially available polyurethane dispersions that are suitable for use as component ( b ) in the compositions of the present invention include : witcobond w 290h , w - 290h , w - 296 , and w213 ( uniroyal chemical division , crompton corporation , middlebury , conn . ); dispercoll u42 , bayhydrol 121 , and bayhydrol 123 polycarbonate polyurethane dispersions ( 100 bayer road , pittsburgh , pa . 15025 ); sancure 2710 and 2715 aliphatic polyether polyurethane dispersions ( noveon , inc . cleveland , ohio ); neorez r - 966 , r - 967 , r - 9603 aliphatic polyurethane dispersions ( neoresins division , avecia , wilmington , mass .). alternatively , for nylon fabrics the additive may also be a dye fixative agent . without being bound by any one particular theory of the mechanism of interaction and the improved results obtained from using a dye fixative agent in association with permethrin , it is thought that permethrin will “ bond ” with the fixative into the fabric and make it more durable to home laundering . the dye fixing agent can be any of a variety of fixing agents known for application to polyamide fiber to improve dye washfastness . these agents are typically compounds or low molecular weight polymers with anionic groups which can associate with the nitrogen - containing groups of the polyamide polymer and form a surface layer that reduces diffusion of the dye out of the treated fiber . “ syntan ” is usually used to describe the class of synthetic fixing agent including condensation products of aromatic sulfonic acids and formaldehyde that are in common usage in the industry for acid dye fixation on nylon . syntans and their derivatives include sulfonated napthol - formaldehyde condensation products ; sulfonated phenol - formaldehyde condensation products ; polymers of methylacrylic acid or its alkali metal salt , and up to 70 weight percent of one or more monomers having ethylenic unsaturation and containing 2 to 20 atoms ; a polymer of maleic acid or fumaric acid , or alkali metal salts thereof , and up to 70 weight percent of an ethylenically unsaturated aromatic comonomer containing 2 to 20 atoms ; polymers of alpha - substituted acrylic acids or esters polymerized in the presence of a sulfonated aromatic formaldehyde condensation polymer ; and polymers of a sulfonated hydroxyaromatic ester of an alpha - substituted acrylic acid or acrylic acid . syntans are commercially available and are sold , for example , under the trademarks erional ® ( ciba - geigy corp , greensboro , n . c . ), intratex ® ( crompton & amp ; knowles corp ., stamford , conn . ), mesitol ® ( mobay corp . pittsburgh , pa . ), and nylofixan ® ( sandoz chemical corp ., charlotte , n . c .). the preferred dye fixing agents in the practice of the invention are sulfonated naphthalene formaldehyde condensates , sulfonated phenol formaldehyde condensates , dihydroxy diphenyl sulfone formaldehyde condensates , and mixtures thereof . in the case of insecticidally treating a polyester fabric , the retention additive is a polymeric binder . more particularly , the polymeric binder is a polyester polymer or resin . the use of polyester ( co ) polymers for treating fibers , including polyester fibers and fabrics , is known in the art . the following patent disclosures exemplify such polymers and uses : u . s . pat . nos . 3 , 712 , 873 , 3 , 893 , 929 , 3 , 959 , 230 , 3 , 962 , 152 , 4 , 027 , 346 , 4 , 125 , 370 , and 4 , 370 , 143 . in one or more embodiments of the invention , the polyester polymer is preferably comprised of a reaction product of a polyalkyleneglycol , an aromatic dicarboxylic acid , and a glycol . the polyalkylene glycol component of the polyester may be those normally having an average molecular weight in the range of 600 - 12 , 000 , preferably in the range of 1 , 000 - 5 , 000 , and may include polyethylene glycol , polyethylene glycol - polypropylene glycol copolymer , polyethylene glycol - polytetramethylene glycol copolymer , polypropylene glycol and polyhydric alcohol - ethylene oxide adduct etc . other examples of usable alkylene glycols are monophenylethers , monoethylethers and monomethylethers of polyethylene glycol and polypropylene glycol . the dicarboxylic acid component has the following general formula hooc - a - cooh , wherein a is a bivalent organic radical selected from the group consisting of alkylene , arylene , aralkylene , alkarylene and cycloalkylene radicals having from 3 to about 14 carbon atoms . preferably , the dibasic carboxylic acid is an aromatic dicarboxylic acid . the glycol component is a compound having the following general formula ho — x — oh , wherein x is a bivalent organic radical selected from the group consisting of alkylene and cycloalkylene radicals having from 2 to about 4 carbon atoms . when x is alkylene , examples of suitable radicals are ethylene , propylene and butylene , and when x is a cycloalkylene radical , examples of suitable radicals are cyclopropylene and cyclobutylene . representative polyesters suitable in the practice of the invention include terephthalic acid - alkylene glycol - polyalkylene glycol , terephthalic acid - isophthalic acid - alkylene glycol - polyalkylene glycol , terephthalic acid - alkylene glycol - polyalkylene glycol monoether , terephthalic acid - isophthalic acid - alkylene glycol - polyalkylene glycol monoether . more preferably , the polyester polymer comprises a poly ( c 2 - c 4 ) alkyleneterephthalate ( e . g ., polyethyleneterephthalate or polytetramethylene - terephthalate ) or mixtures thereof . an example of suitable polyester polymer is a proprietary material available under the tradename pomoco253 ( a product of piedmont chemical industries i , llc in high point , n . c .) which is a polyester derived from terephthalic acid and glycols . another suitable polyester polymer is the next generation of pomoco 253 , named pomoco 253 - p and also available from piedmont chemical industries i , llc in high point , n . c . for fabric blends of polyester and cotton , or even fabrics that are entirely cellulosic , the present inventors have found that an effective polymeric binder system for the permethrin may also be crosslinking agent . crosslinking agents are widely used in the textile industry in the dyeing of certain fabric types ( e . g ., cellulosics ) or to impart desirable properties to the textile ( e . g ., wrinkle recovery or crease resistance , tensile strength , and fabric smoothness ). for example , the disclosures of u . s . pat . nos . 4 , 629 , 470 and 5 , 298 , 584 pertain to cellulosic substrates intended for eventual dyeing and which are pre - treated with finishes in order to render the fabric surface more receptive to dyes and to improve color strength of the dyed product . such finishes comprise as major components a crosslinking agent , a catalyst and other reactive additives such as glycols or choline chloride that graft to the crosslinking agent . u . s . pat . no . 4 , 396 , 391 provides a crosslinking agent for use as a crease - resistant finish for cellulose - containing textiles , which crosslinking agent is a reaction product of dimethylol dihyroxyethylene urea ( dmdheu ) or an alkylated dmdheu with a polyol . crosslinking agents useful in the present invention are those which preferably possess multiple reactive sites . these include , for example , dimethylol urea , partially methylolated urea , dimethylol ethyleneurea , dimethylol propyleneurea , dimethylol dihydroxyethyleneurea ( dmdheu ), alkylated dmdheu , trimethylol acetylenediureine ( 3acd ), tetramethylol acetylenediureine ( 4acd ), and methylol melamine ( tmm ), dimethylol propyl carbamate , and forms of these that have been modified by grafting , e . g ., with polyalkylene glycols of suitable molecular weight . in a preferred embodiment of the invention , a dmdheu / peg modified crosslinking agent is effective in enhancing the wash durability of permethrin - treated cotton and cotton / polyester blend fabrics . depending on the fabric being insecticidally treated , the polymer binder , crosslinking agent or dye fixing agent , is added to the same bath to which the permethrin ( or other insecticide ) is also added . the binder , crosslinker or dye fixative is present in the pad bath in an amount that varies widely from 0 . 01 to 20 % by weight of the bath size ; the wide range specified is reflective of the fact that the amount of binder , crosslinking agent or dye fixative necessary will be dependent upon the wet pick - up of the fabric . generally a fabric with a higher wet pick - up value will require a smaller amount of binder , crosslinker or dye fixative in the pad bath , and a fabric with a lower wet pick - up value will require a larger amount . thus , the amount of “ the additive ” needed depends on the type of fabric being treated ( e . g ., nylon , polyester , cotton , acrylic ) and the relevant textile properties thereof ( i . e ., at least the wet pick - up of the fabric ). more preferably the binder , crosslinker or dye fixative is present from about 0 . 5 to 10 % by weight of the bath size , and in a preferred embodiment “ the additive ” is present from about 1 to 3 % by weight of the bath size . what is essential about the amount of additive used is that it be the least amount necessary to achieve the enhanced durability of the insecticide without being detrimental to the desired hand , or feel , of the fabric . in a less preferred and alternate embodiment , the fabric can be treated sequentially , rather than the preferred method of padding the fabric in a single pad bath that contains both the retention additive and the permethrin . thus , for example , the fabric can be treated or padded with the polymeric binder , crosslinking agent or dye fixative agent at one point in time at one location , and then be padded with insecticide at a later point in time , and possibly at a different location , provided that the interim time and conditions to which the fabric is exposed ( between the first pad and the second pad ) do not have a significant adverse affect on the binding of insecticide to the fabric and the level of enhanced wash durability achieved herein . following impregnation , the fabric is typically subjected to at least one after - treatment conventional in textile processing . for example , the insecticidally treated fabric can be subjected to drying or curing following the padding or exhaust application . additionally the fabric may be after - treated with customary finishes to improve , e . g ., the hand , water repellancy , wrinkle resistance , brightness , antibacterial nature of the textile , provided that none of these additional agents interfere with either the extended wash durability or the insecticidal efficacy . additional finishes could be combined with permethrin as above with the dye fixative agent . these additional finishes include a . uv absorbing chemistry such as sunlife klp from nicca or tinofast cel ( uv sun cel ) from huntsman that are used to make the fabric / garment protect the weared from the harmful uv rays of the sun . b . moisture control treatments that make fabrics hydrophilic such as milease t from clariant or feran ice from rudolph chemie . c . water and oil repellent chemistries such zonyl 7040 from dupont / huntsman or nuva n2114 from clariant . the fabrics and fibers of the invention exhibit a retention of insecticide in the range of from about & gt ; 20 % to about & gt ; 90 % after 50 launderings . the following examples are provided solely to illustrate the invention , and not to limit the scope of the invention to the particular fabrics , polymeric binders and / or dye fixative agents used therein . a polyester warp fleece weighing approximately 7 . 6 oz . per linear yard was used in this trial . based on the weight of the fabric , calculating the percent wet pick - up the of fabric using production squeeze pressures in the pad application , and the amount of permethrin target ( 1 . 25 g / m 2 ), the quantity of permethrin to be added to the pad bath was calculated using the above equation to be 1 . 68 %. also added to the pad bath was a polyester - based binder system ( pomoco 253p ) at 2 . 50 % based on the weight of the bath . the fabric was padded and dried at a normal drying temperature for polyester ( 330 to 350 ° f .). after the application of permethrin to the fabric , samples of the treated fabric were extracted with toluene according to the procedure outlined below in order to determine the amount of permethrin loaded onto the fabric . a swatch of fabric measuring approximately two feet by two feet is cut from the treated roll of fabric . from that swatch , 3 smaller pieces measuring 10 cm by 10 cm , were cut and used for extraction of permethrin . each 10 by 10 swatch was placed in a 250 ml flat - bottomed flask , and from 50 - 75 ml of an extraction solvent ( e . g ., 1 , 1 , 1 - trichloroethane ) was added thereto . the flask was then equipped with a reflux condenser and placed on a hot plate and allowed to reflux for 0 . 5 - 0 . 75 hr . once the samples have finished refluxing and have cooled , 0 . 05 mg / ml of dioctylphthalate (“ dop ”) is added to the liquid fraction as an internal standard for gas chromatography (“ gc ”). known standard solutions of permethrin and dop are prepared for comparison to what has been extracted from the swatches . the calculation used in conducting the gc analysis is as follows : next , 10 × 10 inch swatches of the treated fabric were subjected to one or more machine launderings in a laundrometer using the accelerated laundering test ( test method 61 - 1996 ) specified by the aatcc , in order to determine how well the permethrin remained impregnated in the fabric after the washings . after each of the designated washing cycles each swatch of fabric was extracted following the procedure described above in order to determine the amount of permethrin remaining therein . the results are shown in the following table : the results clearly show that initial load of permethrin is impressively retained ( 92 - 97 %) in the fabric in the presence of the binder according to the invention , even after 10 machine washings . without incorporation of the binder system of the invention , permethrin washes out of the fabric at nearly 60 - 80 % of the initial amount loaded just after the first wash ( e . g ., 0 . 20 - 0 . 30 g / m 2 or less of permethrin remaining ); not surprisingly , the amount remaining diminishes rapidly with successive launderings . in another test run on a polyester fabric treated with pomoco 253 - p , impregnated with permethrin , and subjected to repeated launderings and extractions using procedure similar to that described in the above example , permethrin was retained at 90 % of the initial load after 50 launderings . additional durability testing ( for testing purposes only ) ( type of fabric : polyester ) were done and the results are as follows : the fabrics of the invention were also tested against deer ticks and mosquitoes and the efficacy is in no way hindered by the binder in the permethrin applications . these tests were conducted on both nylon and polyester fabric . nylon fabrics were also evaluated using a poyurethane binder known as ( polyester polyol aliphatic isocyanate urethane dispersion ) two products were used from crompton corp ., witcobond dispersions group in tarrytown , n . y . ( witcobond w - 296 latex and witcobond w - 290hsc ). the polyurethane binders of the invention also provide for highly effective permethrin retention . a nylon cordura fabric was treated with the permethrin and polyurethane binder using the procedures described above for the polyester fabrics and the following results were obtained : a 100 % cotton fabric utilizing pomoco bz 1 binder system was treated and the following results were obtained prior and after washing : numerous other fabrics have been treated with the method of the invention and the results of those treatments and the % retention of insecticide are summarized in the tables below . while the invention has been specifically illustrated and described in connection with numerous embodiments and further defined in the appended claims , modifications to the various embodiments are within the spirit and scope of the present invention and will be readily apparent to those of skill in the art .
the invention provides a method for preparing insecticidally treated textile having improved properties . a novel combination of an insecticide and certain polymeric binder or dye fixatives is used to coat and / or impregnate fabric via a combination of application methods used in the textile industry . the insecticide - binder or insecticide - dye fixative combination and the method by which it is applied to the textile yield a coated fabric and , ultimately , finished goods with improved wash durability of the insecticide over several launderings and prolonged insecticidal efficacy .