FIELD OF THE INVENTION

The present invention relates to a process of manufacturing controlled release polymer fabrics for pest control. More particularly, the invention relates to a controlled release polymer fabrics made up of insecticide incorporated polymer filaments with long lasting shelf life. In further scope of the present invention, plurality of such filament types each containing a different class of insecticide that not only differ in their chemical nature but also in their mode and/or mechanisms of action are combined into a fabric to effectively fight against susceptible as well as resistant strains of household/agro pests.

BACKGROUND OF THE INVENTION
Vector-borne diseases (VBD) such as malaria, leishmaniasis, trypanosomiasis, chagas disease, lymphatic filariasis, onchocerciasis, dengue, yellow fever and encephalitis have become a major public health concern all over the world and especially in developing countries. The leading causes of the VBD are helminthes and apicoplast parasites. Though the etiological agents of pathogens belong to different types, the disease propagating vectors are almost exclusively arthropods. The arthropod vectors carry the pathogens from one host to another and transmit the diseases. The VBD transmission to humans depend on three different factors namely, the pathologic agent, the arthropod vector, and the human host. Although complete eradication of VBDs is difficult due to their zoonotic nature of transmission, overcoming the misery of VBDs can be achieved through multidiscipiinary approaches includes: (a) controlling of pathogens, (b) curbing the vectors, and (c) improving public sanitation..

The methods used presently for controlling pests are proving to be ineffective due to developing resistance against pesticides by insects. The common methods to control these insects include surface treatment, air spraying, smoking and impregnation of curtains and bed-nets.

Another method includes impregnation of textiles with insecticides. Impregnation is mostly done by dipping the textile material into emulsions or dispersions of insecticides or spraying them onto the nets. Since this provides only a loose adhesion of the insecticides molecules on the surface of the fibers, this treatment is not wash permanent and has to be repeated after each washing.

Studies have proven long-lasting insecticide-treated nets to be more reliable in preventing vector-borne diseases in comparison with conventional nets and spraying. The same has to be re-treated or re-impregnated with insecticide after certain number of washings. The pre-treated and long-lasting insecticide-treated net is also recommended by World Health Organization as an effective means for minimizing vector-borne diseases such as malaria and dengue. This is not only comfortable for the user but gives an economic advantage as well, saving the costs for repeated chemical treatments. It is an environmental advantage as well, since the permanent treatment is done under controlled conditions in textile finishing plants.

State of the art describes coating technology wherein an insecticide/ repellant or a combination of them is fixed on to the surface of the fiber by a polymeric binder or a dye fixative agent. The available prior art claims the impregnation of chemical on the fiber i.e. 'superficial impregnation' however it is not "true" impregnation. Using the state of the art technologies, the active chemical is not incorporated into the fiber. The true impregnation implies where the active chemical is infused into the fiber during the process of extrusion of the filament/yarn.

During the incorporation process various additives to enhance the extrusion are used. The commonly used processing additives such as stearates and amides help in dispersion of pigments and fillers they bloom and are migratory. The migration tendency affects the retention of insecticide in the polymer. Moreover, stearates require higher processing temperature during extrusion and this leads to thermal degradation and in cases like pyrethroids (deltamethrin) thermal induced isomerization takes place and a small percentage of the active ingredient is converted to an inactive isomeric form.

US 5,238,682 discloses the fiber surface coated or deposited with a mixture of pesticide and due to which the interior of the fibers is impregnated with a mixture. However, this impregnation of chemical on the fiber in said application is superficial impregnation and not a true impregnation. The true impregnation implies where the active chemical is infused into the fiber during the process of extrusion.

US 5,631,072 discloses the manufacture of fabric intended to be made into washable garments, more specifically to the placement of an insecticide such as permethrin in the fabric by impregnation with polymeric binders and a cross-linking agent, or by surface coating with a polymeric binder and a thickening agent to improve the efficiency as an insect repellent and retention of the permethrin in the fabric as an effective insecticide through successive washings of the garments. The amount of insecticide in the solutions for impregnation of the fabric is very high (1250 mg insecticide per m2).

US 20070196412 discloses an impregnated textile material or plastics material comprising at least one insecticide and/or at least one repellent, and at least one binder and processes for impregnation of a textile material or plastics material and a process for coating of a textile material or plastics material.

The available prior arts do not provide sufficient wash fastness and long lasting bio-efficacy and combination of insecticides to handle resistant species, and the present invention is concerned with a solution to this problem. Therefore, what is needed is a wash durable insecticide treated fabric wherein the active ingredient is easily incorporated into the fabric without any binder and is prevented from being washed off by being slowly released from the reservoir inside the surface. What is needed is to use of combination of polymeric yarns/ filaments each incorporated with different insecticides and independently released in a controlled manner from the cores of the filaments/yarns.

OBJECT OF THE INVENTION

The main object of this invention is to provide insecticides incorporated controlled release polymer fabrics for pest control including the resistant species.

Another object of this invention is to provide a process to incorporate the pesticides inside the fiber.

Another object of this invention is to provide very high wash durability, high retention and long-lasting fabrics incorporated with pesticides.

Another object of this invention is to provide additives to improve retention index for the insecticide in polymer fabrics.

it is an object of the present invention to increase the functional period over which the fabric incorporated with insecticide is effective, without being required to increase initial insecticide concentrations.

SUMMARY OF THE INVENTION

The present invention relates to the process of manufacturing controlled release fabrics, made of insecticide incorporated polymer filaments selected from the group of, but not limited to, multifilament, monofilament, tape yarn and etc. More particularly, the invention relates to controlled release polymer fabrics made up of insecticide incorporated polymer filaments. In further scope of the present invention plurality of such filament types each containing a different class of insecticide that not only differ in their chemical nature but also in their mode and/or mechanisms of action are combined into a surface structure to effectively fight against susceptible as well as resistant strains of househofd/agro pests.

DESCRIPTION OF THE INVENTION

The present invention relates to a process of manufacturing controlled release fabrics, made of insecticide incorporated polymer filaments selected from the group of but not limited to multifilament, monofilament, tape yarn etc. More particularly, the Invention relates to a controlled release polymer fabrics made up of insecticide incorporated polymer filaments with long lasting shelf life.

In the present invention, linear low density polyethylene (LLDPE) or polypropylene (PP) master batch contains various Active Ingredients (Al) such as dertametbrin, bifenthrin, fipronil and alike, which are extruded in the form of granules. Concentration of Al in a master batch depends on the nature of insecticide, its thermal stability to withstand extrusion temperature, and the final concentration of Al in the fabric to be manufactured.

In the present invention, master batch is then mixed with the polyolefin granules (high density polyethylene HDPE or PP) and the let-down-ratio (LDR) is decided on the basis of the final concentration of Al required fight against the target pest. If necessary a pigment and functional additives such as antioxidants and UV inhibitors are added during the extrusion of yarn or the master batch itself to enhance the functionality of the end product. The monofilament, multifilament or tape yarn is then extruded at a temperature range of 120'C-250 X. The temperatures of different extrusion zones depend on the polymer matrix and thermal stability of the Al incorporated into the filaments/ yarns. The yarn thickness is varied from 50-350 deniers and this again depends on the infusibility of the Al to be released in a controlled manner, and the nature and purpose of the fabric. The controlled release of an Al from polymer matrix is governed by the molecular mass, vapour pressure of the Al, area of cross section of the fibre and the nature of the polymer matrix,

A combination of two or more such yarns thus produced each incorporated with different Al is used in making the combination fabrics. Four types of fabrics namely, monofilament warp knitted fabric, multifilament warp knitted fabric, multifilament jacquard woven fabric, and poly-woven sheets were manufactured. In the present invention, the Al combination and the nature of the fabric could be chosen based upon the target pest, its resistance to an insecticide and the desired purpose of application of the new combination fabric. The Ais differ in their mode of action and or mechanisms of action which delays the process of resistance development by a target pest for a given Al.

The insecticidal property of the fabric thus produced is due to the dual action of the active ingredients which results in better bio-efficacy through synergy achieved through a combination of two or more different classes of insecticides. For example, sodium channel blockers such as pyrethroids (Class-A) and nicotinic acetylcholine receptor (nAChR) agonist such as neonicotinoids (Class-B), nAChR agonist and insect growth regulators such as juvenile hormone mimics (Class C) or sodium channel blockers and gama-aminobutyric acid (GABA) receptor blockers are used in different combinations. Thus, the insecticides not only differ in their chemical constituents but also in their mode and/or mechanisms of actions. Further, two active Ingredients and a synergist can also be combined to enhance the activity of an Al for improved bio-efficacy.

In the present invention, the textile product thus manufactured does not use any binder to fix the insecticide on the surface, instead has the insecticides incorporated into the filaments/yarns and thus utilizes a true controlled chemical release technology to achieve long-lasting bio-efficacy and very high wash durability.

In the present invention, additives comprising of copolymer containing acid groups are used to improve retention index for the insecticide in polymer fabrics. These additives also help to attain better dispersion of insecticide, pigments, fillers and help in reducing the processing temperature preventing any thermal degradation of the insecticides during processing. Use of the copolymeric additives with acidic groups as processing additives help in minimizing wastage of active ingredients by avoiding/reducing thermal decomposition, degradation or isomerization of the pesticide.

Thus, pest control becomes economical, safer and more environmental friendly because of unnecessary loading of hazardous chemicals into the environment by eliminating repeated pesticides spraying. Bed bugs are the primary target pest. However, the fabric is expected to have knockdown and mortality for other household pests including but not limited to roaches, ants, termites, ticks, sand fly, silver fish, house fly, mosquitoes, and spider, in the present invention, molecules of an Active Ingredient (Al) diffuse through the polymer matrix to the surface of the filaments until equilibrium is reached and this maintains the concentration of an Al available to kill the pest(s) on the surface of the fabric. The concentration is lethal for the pest(s) and far too less to be toxic for a human. Most of the Al is inside the polymer matrix like a reservoir and replenishes the Al lost from the surface by abrasion, washing etc.

The rate of diffusion of an At through the polymer matrix depends on its molecular mass, vapor pressure, molar concentration, filament thickness, crystalinity of the polymer matrix and the diffusion controlling additives in the polymers. Hence, the release characteristics of a controlled release fabric is fine tuned for sustained maximum bio-efficacy by manipulating some or all of the factors mentioned above. Furthering to this, the concentration of an Al in unit area of the fabric can further be adjusted by changing the pattern or surface structure of the fabric by increasing/decreasing the frequency of filaments containing a particular Class of Al. This provides a unique mode of controlling the pesticide availability and makes it possible to custom design the fabric based on prevailing insecticidal resistance history. For example, in an area that has reported resistance of a target pest for pyrethroids, concentration of the chemical that acts by different mode of action will be increased while keeping pyrethroid concentration minimum by changing surface structure of the fabric or the fabric pattern or pyrethroid incorporated yarns will be replaced by chemical of different class while manufacturing the fabric.

Accordingly, in a preferred embodiment of the present invention is disclosed a method for preparing controlled release polymer fabrics, comprising the steps of extrusion of active ingredients into master batches in the form of granules with copolymer additives; mixing of active ingredient granules thus obtained with high density polyethylene HDPE, LLDPE, LDPE or Polypropylene; extrusion of filaments at temp 120*C-250 *C and incorporation of filaments with said active ingredients combining two or more impregnated or Incorporated filaments or yarns to produce a wash durable insecticidal fabrics wherein:

the said filament includes but not limited to monofilaments, multifilaments, tape yarns, fibers and alike; the said active ingredients are infused or incorporated into the filament using the process of extrusion; the said copolymer additives are those with acidic groups so as to enhance the retention index of the active ingredient in the polymer and also help reducing the temperatures during the extrusion process; the said incorporation occurs within the fiber and only a small fraction of active ingredients diffuse from the filament core to the surface of the fiber; at least one active ingredient is used for a single yarn and a combination of plurality of yarns having plurality of active ingredients or plurality of class of chemicals are woven or non-woven or knitted together in the fabric; and each active ingredient is released
independently without interference from the other.

In another preferred embodiment of the present invention the said active ingredients are extruded from but not limited to master batch of linear low density polyethylene LLDPE, HDPE, LDPE or polypropylene PP.

In yet another preferred embodiment of the present invention the said active ingredients are selected from but not limited to fipronil, bifenthrin, deltamethirn, alpha-cypermethrin or a combination thereof.

in another embodiment of the present invention the concentration of active ingredients in a master batch depends on the nature of insecticide, its thermal stability to withstand extrusion temperature, and the final concentration of active ingredients in the fabric to be manufactured using the master batch.

In still another embodiment of the present invention the molecules of active ingredient diffuse through the polymer matrix to the surface of the filament until equilibrium is reached to maintain the concentration of the active ingredient on the surface of the fabric.

In still another embodiment of the present invention the concentration of an active ingredient in a unit area of the fabric is alternatively adjusted by changing the pattern of the fabric or surface structure of the fabric which includes the type and shape of filament or yarn or by increasing the frequency of a particular filament containing a particular class of active ingredient.

In yet another preferred embodiment of the present invention a method for preparing controlled release polymer fabrics is disclosed wherein the extrusion of active ingredients in the form of granules is done with copolymer additives with high density polyethylene HDPE, LLDPE, LDPE or polypropylene thus obviating the requirement of preparing master batch.

In yet another preferred embodiment of the present invention is disclosed a controlled released polymer fabric comprising of active ingredient incorporated polymer filaments having high wash durability wherein the said filament includes but not limited to monofilaments, multifilaments, tape yarns, fibers and alike; the said active ingredient is selected from but not limited to fipronil, bifenthrin, deltamethirn, alpha-cypermethrin or a combination thereof; at least one active ingredient is used for a single yarn and a combination of plurality of yarns having plurality of active ingredient or plurality of class of chemicals are woven or non-woven or knitted together in the fabric; and each active ingredient is released independently without interference from the other.

In another embodiment of the present invention the molecules of active ingredient diffuse through the polymer matrix to the surface of the filament until equilibrium Is reached to maintain the concentration of an active ingredient on the surface of the fabric.

In yet another preferred embodiment of the present invention is disclosed a controlled released polymer fabric comprising of active ingredient coated polymer filaments having high wash durability wherein the said filament includes but not limited to monofilaments, multifilaments, tape yarns, fibers and alike; the said active ingredients are preferably fipronil and bifenthrin; combination of yarns having coating of fipronil and yarns having coating of bifenthrin are woven or non-woven or knitted together to form the fabric; and the said coating of active ingredients is achieved by the methods known in the state of the art.

Now, the present invention will be described in further detail with reference to Examples and various
Tables. However, it should be understood that the present invention is by no means restricted by such specific Examples and Tables.

EXAMPLE 1
Preparation of Master Batch
A master batch (MB) contains higher concentration of an Al, dispersants and carrier resin. Four different master batches are manufactured. The Ai contents along with the Al used are given in Table 1.

Table 1

The polymer matrix of master batch is LLDPE or polypropylene. In addition to the Al, master batches contain and other processing aides based on the application and the type of yarn to be extruded in the next stage.

EXAMPLE 2 Preparation of Yarns
Three types of yarns are extruded and they are polyethylene monofilament, polypropylene multifilament and polypropylene tape yarn. The insecticide and the concentration of Al in different yarns extruded are given in Table 2.

TABLE 2
EXAMPLE 3

Preparation of Combination Fabrics

1. Monofilament warp knitted fabric

Two different monofilament yarns each incorporated with different Als are used in making the new combination fabric that releases different Als independently in a controlled manner, in warp knitting machines this is achieved by using different yarns in the set of Ground bar-1 (front beams) and Ground bar-3 (rear beams). Usually more yarns are drawn from the front beams during knitting and thus, the concentration of Al in the fabric can be varied by choosing the Ai incorporated in the Ground Bar-1 and Ground bar-3. For example, the yarns containing 0.5% bifenthrin is loaded in the Ground Bar-1 and combined with yarns containing 0.4% fipronil in the Ground bar-3 the final concentration of Als in the combination fabric is approximately 0.35% bifenthrin and 0.12% fipronil. When the Ground bar-1 and Ground bar-3 are swapped the At concentration of the fabric is approximately 0.3% fipronil and 0.15% bifenthrin. Thus, the Al contents in a fabric can be changed after extruding the yarns. The present invention takes advantage of intricate knitting procedures to manufacture insecticide incorporated long lasting insecticidal fabrics. The Al contents of two such fabrics BF and FB (the nomenclature BF and FB Indicates the Insecticides Incorporated In the yarns In the Ground Bar-1 and the Ground bar-3) manufactured are given in Table 3.

2. Poly woven sheet
Two types of polypropylene tape yarns were extruded. One was incorporated with fipronil and the other with bifenthrin (Al contents of them are given in Table 2). The two tape yarns were used to manufacture poly woven sheet. As every tape yarn is crossing the other like the warp and the weft the concentration of the Als in the final fabric is approximately 50% of their concentration in individual tape yarns.

3. Multifilament jacquard woven fabric
Multifilament polypropylene yarns incorporated with alpha-cypermethrin was combined with polyester yarns to manufacture a fabric in a jacquard machine. This example is included in the present invention to illustrate the application to jacquard fabrics which might be used as curtains etc.

TABLE 3

EXAMPLE 4
Comparison of Wash durability

Wash resistance of the fabrics was studied by determining the Ai content after washing sample fabric pieces for definite number of times. All the fabrics were subjected to a wash-dry cycle upto 20 washes and the wash resistance was determined at six definite wash-dry cycles namely 1,3,5,10,15 and 20. The results are given in Table 4.

TABLE 4
EXAMPLE 5
Bio-efficacy against bed bugs

Bed bugs are wingless insects that belong to the family cimicidae. Bed bugs and other members of the family thrive by sucking blood from birds and animals. The two species that feed on humans are the common bed bug Cimex lectularis and the tropical bed bug Cimex hemioterus. Bed bugs undergo metamorphosis in five stages. The juvenile stages are known as nymphs. Nymphs look very much like their adults but smaller and sexually immature. The nymphs grow to adults by moulting and each nymph must have a blood meal to move to the next stage. Complete life cycle from egg to adult requires five weeks to two months. The period depends on temperature and availability of food (blood). The optimum temperature for rapid development is around 25 "C. Bed bug can live without feeding for many days. The adult survive longer than the nymphs.

Bed bugs are not vectors of any known disease. Hence, do not transmit disease. However, their bites can be uncomfortable and in some cases it cause severe allergic reactions. Due to the use of pesticides bed bug population dropped after the World War II in many countries. However, in the last ten years there is alarming resurgence of bed bugs in several countries across the Europe, Mexico, the USA, Australia and also in Asian countries. There is an increase use of pesticide formulation that contains synthetic pyrethroids such as deltamethrin (suspend SC), permethrin, lamda-cyhalothrin (demand CS), esfenvalerate (Onslaught)*. Due to the extensive use of pyrethroids some bed bug populations have developed resistance to pyrethroid insecticides. Hence, non-pyrethroid pesticides such as chlorfenapyr (Phantom)*, (S)hydroprene (Gentrol)* have become popular. However, they are not very effective like pyrethroid. Chlorfenapyr requires ten days to kill the bugs. Hydroprene being an insect growth regulator prevents moulting of nymphs and renders the adults sterile. Hence, hydroprene formulations are to be used in conjunctions with other insecticides. Formulations containing combination of insects are also reported.

Bio-efficacy of the new insecticide incorporated insecticidal fabrics manufactured by combination of yarns incorporated with bifenthrin and fipronil incorporated fabrics against susceptible and pyrethroid-resistant bed bug adults and nymphs, Cimex lectularius, was assessed in laboratory tests. Bifenthrin is a pyrethroid acts by blocking the sodium channel while fipronil is a phelypyrazole acts by blocking gamma-amlnobutyric acid (GABA) receptor. Bio-efficacy trials of warp knitted fabrics and poly woven sheets that differ in their insecticide against mixed stages nymphs and adult be bugs are given in Table 5 and Tabie 6, respectively.

TABLE 5
UT is Untreated control fabric, CNBF is monofilament fabric knitted with bifenthrin incorporated yarns in front warping beam andfipronil incorporated yarns in the rear warping beams, CNFB is monofilament fabric knitted withfipronil incorporated yarns in front warping beam and bifenthrin incorporated yarns in rear warping beams, PyB Is monofilament fabric knitted with bifenthrin incorporated yarns in both front and rear beams, PWSBF is poly-woven sheet made from bifenthrin incorporated polypropylene tape yarns and flpronil Incorporated polypropylene tape yarns.

TABLE 6
UT is Untreated control fabric, CNBF is monofilament fabric knitted with bifenthrin incorporated yarns in front warping beam andfipronil incorporated yarns in the rear warping beams, CNFB is monofilament fabric knitted withfipronil incorporated yarns in front warping beam and bifenthrin incorporated yarns in rear warping beams, PyB is monofilament fabric knitted with bifenthrin incorporated yams in both front and rear beams, PWSBF is poly-woven sheet made with bifenthrin incorporated polypropylene tape yarns andfipronil incorporated polypropylene tape yarns.

EXAMPLE 6
Method of detection of Al in fabric
Active ingredient in a incorporated yarn, master batch or fabric was determined by heating the fabric, yarn or master batch under reflux for 30 minutes with xylene and determined by Gas Chromatography with Flame lonisation Detection (GC-FID) using the internal standard calibration. Octacosane or dioctyl phthalate was used as the internal standard. In the case of master batches the Al content is much higher and therefore, the xylene solution was suitably diluted to get the Al concentration within calibration range (10 ppm to 300 ppm).

From a fabric piece of length 10 m and width 150 cm five pieces of 25 cm x 25 cm were cut with scissors and put into separate 250 mL screw capped glass bottles for determination of Al content. Each piece was then cut into smaller pieces of 5-10 mm square and homogenized to get combined sample for analysis. Five representative analytical samples were weighed and analyzed for Al content. For determination of retention of Al against washing after 0,1, 3, 5,10,15 and 20 washes three pieces (for each wash cycle) of 25 cm x 25cm were cut with scissors from a fabric of length 10 m and width 150 cm and put into 1 L screw capped glass bottles.

Wash durability i.e. retention of an Al against washing was determined by washing and drying 25 cm x 25 cm fabric piece for definite number of washing-drying cycles. Each individual piece of 25 cm x 25 cm of a fabric was washed with 500 mL 0.25 % soap solution [IEC-A Reference Detergent 60456 without Phosphate] in an equilibrium shaker at 150 revolutions per minute (RPM) with an amplitude at ambient room temperature (about 30°C) for 10 minutes. After washing, the piece is rinsed twice with 500 mL deionized water for each time in a bottle in the equilibrium shaker. After washing and rinsing the fabric piece was line dried at ambient temperature protected from direct sunlight for 30 minutes and then stored
at room temperature for 22 ± 2 hours before the next washing. After the wash cycles, each piece was rolled in an aluminium foil and stored in a freezer at 4°C (± 3°C) until all they were taken out for analysis. Active ingredient content(s) of the fabrics after completion of wash-cycle was determined to calculate the retention (%) of Al against washing by a fabric.

Bio-efficacy of the new insecticide incorporated insecticidal fabrics manufactured by combination of yarns
incorporated with bifenthrin and fipronil incorporated fabrics against susceptible and pyrethroid-resistant bed bug adults and nymphs, Cimex lectularius, was assessed in laboratory tests.

Fabric was put on the bottom of an 8 oz plastic cup and sealed at the edges. Ten blood-fed mixed stage of bed bug nymphs were released on the surface of the fabric. Bed bug nymphs were force exposed to the fabric for 24 hours. Bed bug nymphs and adults were scored for knockdown at 5, 15, 30, 45 and 60 minutes, and 2, 3 and 4 hours after treatments. At 24 hours, bed bug nymphs were transferred to clean containers. Mortality was assessed at 1 to 7 days post-treatment. If 100% mortality was observed at a particular time interval further observation was stopped. Blood meals were provided to each life stage to ensure life cycle development. Ten mixed-sex adults were used for each replicate with five replicates per treatment. Bed bugs used for the bioassay were provided with a blood meal zero to two days prior to use in experiments

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in carrying out the above process and steps set forth without departing from the spirit and scope of the invention is intended that all matter contained in the above description shall be interpreted as illustrated and not in a limiting sense.

It is also to be understood that the following claims are Intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention in which, as a matter of language might be said to fall there between.

We Claim:

1. A method for preparing controlled release polymer fabrics, comprising the steps of:

(a) extrusion of active ingredients into master batches in the form of granules with copolymer additives;

(b) mixing of active ingredient granules obtained in step (a) with high density polyethylene HDPE, LLDPE, LDPE or Polypropylene;

(c) extrusion of filaments at temp 120*C-250 *C and incorporation of filaments with active ingredients of step (a);

(d) combining two or more impregnated or incorporated filaments or yarns to produce a wash durable insecticidal fabrics;

wherein:

the said filament includes but not limited to monofilaments, multifilaments, tape yams, fibers and alike;

the said active ingredients are infused or incorporated into the filament using the process of extrusion;

the said copolymer additives are those with acidic groups;

the said copolymer additives enhance the retention index of the active ingredient in the polymer;

the said copolymer additives help reducing the temperatures during the extrusion process;

the said impregnation occurs within the fiber and only a small fraction of active ingredients diffuse from the filament core to the surface of the fiber;

at least one active ingredient is used for a single yarn and a combination of plurality of yarns having plurality of active ingredients or plurality of class of chemicals are woven or non-woven or knitted together in the fabric; and

each active ingredient is released independently without interference from the other.

2. The method for preparing controlled release polymer fabrics as claimed in claim 1,
wherein the said active ingredients are extruded from but not limited to master batch of linear low density polyethylene LLDPE, HOPE, LDPE or polypropylene PP.

3. The method for preparing controlled release polymer fabrics as claimed in claim 1, wherein the said active ingredients are selected from but not limited to fipronil, bifenthrin, deltamethirn, alpha-cypermethrin or a combination thereof.

4. The method for preparing controlled release polymer fabrics as claimed in claim 2, wherein the concentration of active ingredients in a master batch depends on the nature of insecticide, its thermal stability to withstand extrusion temperature, and the final concentration of active ingredients in the fabric to be manufactured using the master batch.

5. The method for preparing controlled release polymer fabrics as claimed in claim 1, wherein molecules of active ingredient diffuse through the polymer matrix to the surface of the filament until equilibrium is reached to maintain the concentration of the active ingredient on the surface of the fabric.

6. The method for preparing controlled release polymer fabrics as claimed in claim 1, wherein the concentration of an active ingredient in a unit area of the fabric is alternatively adjusted by changing the pattern of the fabric or surface structure of the fabric which includes the type and shape of filament or yarn or by increasing the frequency of a particular filament containing a particular class of active ingredient.

7. A method for preparing controlled release polymer fabrics, comprising the steps of:

(a) extrusion of active ingredients in the form of granules with copolymer additives with high density polyethylene HDPE, LLDPE, LDPE or polypropylene;

(b) extrusion of filaments at temp 120*C-2S0 *C and incorporation of filaments with active ingredients of step (a);

(c) combining two or more impregnated or incorporated filaments or yarns to produce a wash durable insecticidal fabrics;

wherein:

the said filament includes but not limited to monofilaments, multifilaments, tape yarns, fibers and alike;

the said active ingredients are infused or incorporated into the filament using the process of extrusion;

the said copolymer additives are those with acidic groups and do not migrate to the surface;

the said copolymer additives enhance the retention index of the active ingredient in the polymer;

the said copolymer additives help reducing the temperatures during the extrusion process;

the said impregnation occurs within the fiber and only a small fraction of active ingredients diffuse from the filament core to the surface of the fiber;

at least one active ingredient is used for a single yarn and a combination of plurality of yarns having plurality of active ingredients or plurality of class of chemicals are woven or non-woven or knitted together in the fabric; and

each active ingredient is released independently without interference from the other.

8. A controlled released polymer fabric comprising of active ingredient incorporated polymer filaments having high wash durability wherein:

the said filament includes but not limited to monofilaments, multifilaments, tape yarns, fibers and alike;

the said active ingredient is selected from but not limited to fipronil, bifenthrin, deltamethirn, alpha-cypermethrin or a combination thereof;

at least one active ingredient is used for a single yarn and a combination of plurality of yarns having plurality of active ingredient or plurality of class of chemicals are woven or non-woven or knitted together in the fabric; and

each active ingredient is released independently without interference from the other.

9. The controlled release polymer fabric as claimed in claim 8, wherein molecules of active ingredient diffuse through the polymer matrix to the surface of the filament until equilibrium is reached to maintain the concentration of an active ingredient on the surface of the fabric.

10. A controlled released polymer fabric comprising of active ingredient coated polymer filaments having high wash durability wherein:

the said filament includes but not limited to monofilaments, multifilaments, tape yarns, fibers and alike;

the said active ingredients are preferably fipronil and bifenthrin;

combination of yarns having coating of fipronil and yarns having coating of bifenthrin are woven or non-woven or knitted together to form the fabric; and

the said coating of active ingredients is achieved by the methods known in the state of the art.