WO2025120503A1

WO2025120503A1 - Textile fabric for insecticidal nets with improved surface activity using two active ingredients

Info

Publication number: WO2025120503A1
Application number: PCT/IB2024/062155
Authority: WO
Inventors: Anand SAMIAPPAN; Thomas Weis
Original assignee: Vka Polymers Private Ltd
Current assignee: Vka Polymers Private Ltd
Priority date: 2023-12-04
Filing date: 2024-12-03
Publication date: 2025-06-12
Anticipated expiration: 2026-06-04

Abstract

The present invention relates to a textile fabric for insecticidal mosquito nets using at least two active ingredients with enhanced insecticidal reservoir utilization for improved surface activity. It is knitted from atleast two monofilaments (MF1 and MF2), wherein the two Active Ingredients (AI1 and AI2) are embedded in different blending ratios in the monofilaments. The monofilaments may be produced by mono-component technology or bi-component technology using core and sheath extrusion design. If produced in mono-component technology all AIs are homogenously distributed within the volume of the entire monofilament. If produced in bi-co technology, a preferential positioning of the AI and eventually SYNergist(SYN) and Migration inhibitor (MI) within the volume of the monofilament can be applied. The preferential positioning of AIs, SYN and MI enables a higher bio efficacy against insects over the product lifetime.

Description

TEXTILE FABRIC FOR INSECTICIDAL NETS WITH IMPROVED SURFACE ACTIVITY USING TWO ACTIVE INGREDIENTS

SUMMARY OF THE INVENTION

The present invention relates to an Insecticidal fabric, warp-knitted from two cylindrical monofilaments (designated as MFI and MF2), containing at least two active ingredients (designated as All and AI2) and active ingredients are embedded in different blending ratios in both monofilaments as demonstrated in (Fig 1).

The insecticidal fabric warp knitted of two cylindrical monofilaments of the present invention having at least two active ingredients, wherein the both Monofilaments may have different diameters as demonstrated in (Fig 2) and one filament has diameter ranging between 25% - 75% larger than diameter of other one.

The present invention also relates to an Insecticidal fabric warp-knitted from two cylindrical monofilaments having at least two active ingredients, wherein a synergist (designated as SYN herein the specification) as chemical entity is also embedded into at least one Monofilament with the objective of enhancing the activity of incorporated active ingredients (All and AI2)

The present invention further relates to the process of preparing the Insecticidal fabric warp- knitted from two cylindrical monofilaments containing at least two active ingredients, a synergist chemical entity wherein the process comprising warp knitted from two monofilaments (MFI and MF2), wherein the two active ingredients (All and AI2) are embedded in different blending ratios in both monofilaments and first filament designated as MFI is produced by monocomponent technology while second filament designated as MF2 is produced in Bi-Co technology using a Core and Sheath design -having Core: Sheath volume ratio ranging between 70%-95% and 5-30% v/v. The Active ingredients (AIs) of MFI are homogenously distributed within the volume of the filament, and the AIs in MF2 are predominantly concentrated in the sheath (Fig 3) while Synergist and/or Migration inhibitor is predominantly used in the core. The warp knitted insecticidal fabric of the present invention is utilized to make ITNs or LLINs having advantages of improved effectiveness of insecticidal activity besides long lasting activity along with improved human safety.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplified illustration of Monofilament (MFI) and Monofilament (MF2) showing distribution texture of Active Ingredients (AIs) and Synergist(SYN)

FIG. 2 is an exemplified illustration of Monofilament (MFI) and Monofilament (MF2) showing different diameters

FIG. 3 is exemplified illustration of Monofilament (MFI) and Monofilament (MF2) showing Bi- Co technology extruded filament possessing well defined Core and Sheath texture with incorporated AIs, SYN etc.

FIG. 4 is exemplified illustration of Monofilament (MFI) and Monofilament (MF2) obtained by Bi-Co technology extrusion of both filament of equal diameter.

FIG. 5 is exemplified illustration cross section of Monofilament (MFI) and Monofilament (MF2) obtained by Bi-Co technology and in a core and sheath design.

FIG. 6 is exemplified illustration of a loop forming process of two monofilament for a two dimensional mosquito net fabric through warpknitting

FIG. 7 is exemplified illustration process of extruding a bi-component Monofilament-Extrusion process

FIG. 8 is exemplified illustration of for cross sections of cylindrical bi-component Monofilaments with different core/sheath surface ratios

FIG. 9 is exemplified illustration of principal setup of a Bi-Component Monofilament Extrusion machine FIG. 10 is exemplified illustration of wash resistance index (WRI) of dual Al incorporated monofilament containing SMI and FMI having identical thickness

FIG. 11 is exemplified illustration of wash resistance index (WRI) of dual Al incorporated monofilament containing SMI and FMI having variable thickness (GB1 thickness 100 Denier and GB2 thickness 200 Denier in 80 :20 ratio respectively)

FIG. 12 is exemplified illustration of wash resistance index (WRI) of dual Al incorporated in Bicomponent technology core/sheath design containing SMI and FMI having identical thickness

DETAILED DESCRIPTION:

Discussed below are some representative embodiments of the present invention. The invention in its broader aspects is not limited to the specific details and representative methods. Illustrative examples are described in this section in connection with the embodiments and methods provided.

It is to be noted that, as used in the specification, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a composition containing “a compound or component” includes a mixture of two or more compounds or components. It should also be noted that the term "‘or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.

The expression of various quantities in terms of “%” or “% w/w” means the percentage by weight of the total solution or composition unless otherwise specified.

Abbreviation used in the patent specification and their explanations

LLIN Long Lasting Insecticidal Net

ITN Insecticidal Treated Net

HDPE High Density Polyethylene

LLDPE Linear Low-Density Polyethylene EDPE low Density Polyethylene

PET Polyethylene Terephtalate, commonly: "Polyester"

MF Monofilament

SYN Synergist

Al Active Ingredient or Insecticide

Bi-Co Bi-Component or 2-Component

PBO Piperonylbutoxide, a specific type of Synergist

SMI Slow Migrating Insecticide

FMI Fast Migrating Insecticide

Mono-Co Mono-Component or 1 -Component

MI Migration Inhibitor

In our endeavor to explain the invention of improved surface-active fabric for insecticide nets using two or more active ingredients, wherein uniquely designed Bi Co Technology is developed to make the fabric economically viable and amenable to scaleup for commercial production.

The embodiments of the present invention provide a two-dimensional textile fabric, which is produced by warp knitting of two cylindrical Monofilaments (designated as MF). The insecticides, which are also called active ingredients (Al) are embedded in the HDPE polymer matrix of the Monofilaments.

The volume of the HDPE Monofilament matrix serves as a reservoir for the insecticides and synergists, which are migrating to the surface of the Monofilament in order to be bio- available for mosquitoes.

Both Monofilaments are made of HDPE, sometimes blended with small amount of EDPE or EEDPE, but with different insecticidal formulations. As discussed in the background section of this patent specification, there is existing prior art in terms of patent EP2170048Blfrom Vestergaard, describing the intermingling of different threads, each of them containing a different insecticide. However, it must be emphasized that the present invention differs from the disclosures of this prior art as the invention is using Monofilaments, which are not intermingled, but knitted together to a textile fabric using a loop-forming process through a specific motion of two needle bars. Further more, a unique difference with respect to the disclosures of patent EP 3 056 084 Bl by Vestergaard et al in the present invention, all insecticides are present in both filaments (Fig 1).

The disclosures of Katiyar-et-al-2014; Development-of-insecticide-incorporated-knitted- fabric-having-long-lasting- efficiency using Bi-Co spinning technology for ITN are neither amenable to scale up nor makes the process to be viable and useful. The disclosure is related to a combination of PET core and HDPE sheath, which is materially different to the present invention. Besides this, the disclosure is using only one insecticide incorporated in two identical filaments, which is a materially different embodiment in the present invention.

In another embodiment of the present invention, different insecticides and biologically enhancing synergists having different migration speed through Monofilaments made in HDPE are used.

In a particular embodiment, liquid synergist used was piperonyl butoxide (PBO) is observed migrating very fast in comparison to pyrethroids alone, which are migrating very slowly. A Monofilament of a mosquito net which is used for about three years in the field has lost normally all PBO content, but it still contains pyrethroids in the core of the filament.

Examples of synergists used in the present invention but are not limited to piperonylbutoxide (PBO), sebacic esters, fatty acids, fatty acid esters, vegetable oils, esters of vegetable oils, alcohol alkoxylates and antioxidants In yet another embodiment of the present invention, it provides using two Monofilament design features to ensure that the different migration speeds are better balanced for optimized utilization of the insecticidal and/or synergetic reservoir of the Monofilament.

The first design feature is the use of two cylindrical Monofilaments in two different diameters in order to achieve different volume/surface ratio in each of the two Monofilaments (Fig 2).

Slow migrating insecticides (SMI), will be predominantly present in the Monofilament with the lower diameter. Fast migrating synergists and/or insecticides (FMI) will be predominantly present in the Monofilament with the higher diameter.

In the particular embodiment of the present invention, it provides, the diameter of MFI is about 135 micron, but it may be also range between 100 and 140 micron in the ambit and scope of the present invention. The diameter of MF2 is kept more and near about 160 micron, but may be also in the range between 135 and 175 micron. However, the diameter of MF 2 is always between 25% and 75% higher than the diameter of MFI.

In the preferred embodiment of the present invention, the two Monofilaments with different insecticidal and synergetic formulations and different diameters are warp knitted in an asymmetric threading together.

In the proposed invention the preferred knitting pattern is a four-lapping, containing over the textile surface approximately 80% of filament length in MFI and 20% of filament length in MF2.

In yet another embodiment of the present invention, the second design feature that at least one of the two Monofilaments is produced using Bi-Component extrusion technology. The two components contained in the filament - individual insecticidal and/or synergetic formulations and are bonded together through an extrusion process. In the preferred embodiment, a round core is surrounded by a sheath of a homogenous thickness. In the preferred embodiment, the core/sheath ratio ranges between 70%:30% and 95%:5%in volume and diameter. The polymer resin carrier is for both, core and sheath of Polyethylene.

The two different Monofilaments are referred at all places as MFI and MF2.

In yet another particular embodiment of the present invention, MFI contains predominantly, but not exclusively a non-pyrethroid insecticide (All). In case MFI is made in Mono-component technology, the predominantly present insecticide is homogenously distributed within the volume of the entire Monofilament.

In case this Monofilament is made in Bi-Co technology, the insecticide is predominantly, but not exclusively present in the sheath of the Monofilament. Predominantly is understood within the context of this innovation as over 90%.

MF2 contains predominantly, but not exclusively a pyrethroid or non-pyrethroid insecticide (AI2). In case a pyrethroid insecticide is used, the invention may also contain PBO as a synergist.

The insecticidal fabric, according to present invention, comprising incorporation of the non- pyrethroid insecticide selected from Chlorfenapyr, Indoxacarb, Fenpyroximate, Emamectin Benzoate, Tolfenpyrad, Metaflumyzone, Cyazofamid or mixtures thereof.

The pyrethroid insecticide can be selected from a-cypermethrin, Deltamethrin, Bifenthrin, Lambda cyhalothrin, Permethrin and Etofenproxor mixture thereof; however, it may include some other advanced pyrethroid insecticides as well.

The combined non-pyrethroid and pyrethroid insecticide content in core and sheath together may be ranging between 0.2-3.0% w/w.

In case MF2 is made in Mono-component technology, the predominantly present insecticide is homogenously distributed within the volume of the entire Monofilament. In case this Monofilament is made in Bi-Co technology, the predominantly present insecticide is mainly, but not exclusively present in the sheath of the Monofilament and the synergist is mainly, but not exclusively present in the core.

Migration mechanisms of AIs and other functional additives within polymers mainly follows concentration gradients. Consequently, AIs will migrate from the highly Al concentrated sheath of the filament towards the low- or un-concentrated core of the filament, mitigating the potency of the Al on the filament surface.

In order to prevent the effect of Al migration into the core, the same mechanism may be used as established to prevent migration of dyes within polymers. The use of block copolymers is by conventional technique in the polymer industry to slow down the migration of dyes within polymers has been investigated by Hariri and Ruch. (https://www.researchgate.net/publication/272537695 Block copolymers as dispersants and migration inhibitors Incorporation of fluorescent dyes in polyethylene). The present invention has used up to 10 % of polyolefin block copolymer, for example DOW’s trademark product- Dow Infuse 9010 may be blended into the core of the filament.

The disclosures in the present application make available each and every combination of embodiments disclosed herein.

Best mode exemplified embodiments are illustrated herein below and based on the figures; however, they shall not be construed to be limiting the scope of invention.

Incorporation Process of Dual AIs in monofilament:

The process of incorporation of dual Ais involves the following methodology.

In the primary step, the polyethylene (LLDPE), used as a polymeric carrier resin, was mixed with Bifenthrin (SMI) and Chlorfenapyr (FMI) in a tumble mixer to create a homogenous mixture. This above-mentioned composition of materials was introduced in solid form into the feed zone of the twin-screw compounding extruder to produce concentrated master batch of active ingredients. This master batch produced was used for the further stages.

This concentrated master batch was diluted in a second step to a High-Density Polyethylene (HDPE), producing Monofilaments, MFI and MF2, containing 7g/kg of technical- grade Bifenthrin, 8g/kg of technical grade Chlorfenapyr.

The above produced master batch, 10% by weight is taken and about 90 % by weight of HDPE were mixed in a suitable or tumble mixer and this mixture was subjected to extrusion usin g a single-screw monofilament extruder.

The polyethylene was supplied to the extruder in pellet form in the feed zone and the active ingredients were dosed as per the desired quantity into the polymer melt the form of concentrated master batch.

The polymeric material of the present invention was used to produce insecticide incorporated monofilament yarns having linear density of about 120 denier,

The polymeric material was melted in a single- screw extruder with temperature controlled to 220+5 °C and extruded through a suitable monofilament die.

Incorporation Process of Dual AIs in Bi-Co-filament:

In the primary step, two separate masterbatches were produced. For both masterbatches, the polyethylene (LLDPE), used as a polymeric carrier resin. This carrier resin was mixed with Bifenthrin for one masterbatch and Chlorfenapyr for the second masterbatch in a tumble mixer to create a homogenous mixture. These above-mentioned compositions of materials were introduced in solid form into the feed Zone of the twin-screw compounding extruder to produce concentrated master batches of active ingredients. These master batches produced shall be used for the further stages. In a secondary step a bi-component monofilament extrusion machine was used. The machine has two separate single screw extruders, able to process in parallel polymeric compounds of different insecticidal formulations and concentrations, which are merged within a suitable bico extrusion die into a bico monofilament. The used bico machine is designed to deliver a core to sheath ratio of 80/20, which means that 80% of the polymer mixture is forming a cylindrical core and 20% if the polymer mixture is forming a sheath, encapsulating the core. In order to produce monofilaments with a delayed release of the fast-migrating insecticide (FMI), Chlorfenapyr we added a higher concentration of masterbatch containing Chlorfenapyr in the extruder processing the core, while at the same time we added a higher concentration of masterbatch containing the slow migrating insecticide (SMI) in into the extruder processing the sheath. The letdown ratios of the masterbatches into the two polymer streams were calculated in such way to achieve the same overall concentration of 7g/kg Bifenthrin and 8g/kg Chlorfenapyr as with monofilament production in mono-component technology.

Filaments produced by monocomponent and Bi-component technology are demonstrated in detail with the figure 1-12 with their illustrations to provide working of present invention in its best mode illustration.

• FIG. 01 illustrates cross sections of two cylindrical monofilaments (MFI and MF2) with identical diameter. Both monofilaments are produced in mono-component technology. Both monofilaments contain two different active ingredients (All and AI2) in different blending ratios and eventually a synergist compound. The active ingredients and the synergist are migrating to the surface of the filament and may be taken up by the insect or mosquito.

• FIG. 02 illustrates cross sections of two cylindrical monofilaments (MFI and MF2) with different diameters. Both monofilaments are produced in mono-component technology. Both monofilaments contain two different active ingredients (All and AI2) in different blending ratios and eventually a synergist (SYN). The active ingredients and the Synergist are migrating to the surface of the filament and may be taken up by the insect/mosquito. Active ingredients and

Synergists with fast migration effect, in this case are illustrated as AI2 and SYN will be placed predominantly in the monofilament with the larger diameter.

• FIG. 03 illustrates cross sections of two cylindrical monofilaments (MFI and MF2) with different diameters. The monofilaments with lower diameter are produced in mono-component technology, while the other one is produced in Bi-component technology (or Bi-Co Technology). The Bi-Co monofilament is produced in a core and sheath design. Both monofilaments contain two different active ingredients (All and AI2) in different blending ratios and eventually a synergist (SYN) and a migration inhibitor (MI). The active ingredients and the synergist are migrating to the surface of the filament and may be taken up by the insect/mosquito. Fast migrating synergists, and the complementary active ingredient, in this case illustrated as SYN and AI2 will be placed predominantly in the Bi-co monofilament. Within this bi-co filament, the fast migration synergist will be placed predominantly in the core, while the slower migrating active ingredient will be placed predominantly in the sheath. The bi-co monofilament contains eventually an additional migration inhibitor (MI) compound, which is predominantly placed in the core.

• FIG. 04 illustrates cross sections of two cylindrical monofilaments (MFI and MF2) with identical diameter. Both monofilaments are produced in bi-component technology and in a core and sheath design. Both monofilaments contain two different active ingredients (All and AI2) in different blending ratios and eventually a synergist (SYN) and a migration inhibitor (MI). The active ingredients and the synergist are migrating to the surface of the filament and may be taken up by the mosquito. In monofilament 1(MF1), the predominantly available active ingredient (All) is predominantly placed in the sheath of the filament. In monofilament 2 (MF2), the fast migrating synergists willbe placed predominantly in the core of the filament, while the complementary active ingredient (AI2) willbe placed in the sheath of the filament. The bi-co monofilaments contain eventually an additional migration inhibitor (MI), which is predominantly placed in the core.

• FIG. 05 illustrates cross sections of two cylindrical monofilaments (MFI and MF2) with different diameters. Both monofilaments are produced in bi-component technology and in a core and sheath design. Both monofilaments contain two different active ingredients (All and AI2) in different blending ratios and eventually a synergist (SYN) and a migration inhibitor (MI). The active ingredients and the synergist are migrating to the surface of the filament and may be taken up by the mosquito. In monofilament 1, the predominantly available active ingredient (All) is predominantly placed in the sheath of the filament. In Monofilament 2, the filament with the larger diameter, the fast migrating synergists willbe placed predominantly in the core of the filament, while the complementary active ingredient (AI2) willbe placed in the sheath of the filament. The bi-co monofilaments contain eventually an additional migration inhibitor (MI), which is predominantly placed in the core.

• FIG 06 illustrates a loop forming process of 2 monofilament to a two dimensional mosquito net fabricthroughwarpknitting.

• FIG. 07 illustrates the process of extruding a bi-component Monofilament-Extrusion process. Two separate extrusion machines (Extruder A for core and Extruder B for sheath) are melting and processing two separate polymer streams. The polymer streams are mixed with various combinations of AIs, SYN and MI withineach extruder. When the polymer streams enter the extrusion die, the polymer stream for the sheathis forming a thin melt lake, while the polymerstream for the core is pressed through a cylindrical hole and injected through the meltlake for the sheath. In thisway the cylindrical core stream is dragging the sheath stream into a subsequent hole, forming a cylindrical monofilament with polymer from core stream in the center and the sheath stream on its surface. By adjusting the processing speed of extruder A and B, the thickness of core and sheath can be adjusted, forming core/sheath designs with different cross-sectional surface ratios.

• FIG. 08 illustrates examples for cross-sections of cylindrical bi-component monofilaments with different core/sheath surface ratios. Worked out Examples: Core about 90% / Sheath about 10% and Core about 70% / Sheath about 30%.

• FIG. 09 illustrates a principal setup of a Bi-Component (Bi-CO) monofilament Extrusion machine, using Extruder A and B in parallel. Both extruders are melting and mixing the HDPE granules, AIs (All and AI2) and eventually SYN and MI are added suitably inside the machine and pressing the polymer compound into an extrusion die. Inside the extrusion die, the polymer melt of the sheath is forming a melt lake, while the polymer of the core is injected through the melt lake and dragging the melt from the sheath through the nozzle. In this way a filament with core and sheath design is being formed.This is indicative of an economically viable machine to make Bi-Co fiber extrusion containing atleast two AIs to make fabric, which inturn may be converted to high quality and safe Insecticidal Treated Nets (ITNs).

• Fig 10 illustrates a graph in wash resistance index (WRI) of an insecticidal incorporated mosquito net. All filaments, produced in mono-component technology have identical thickness (120Denier) and contain the same composition of 2 different insecticides, Bifenthrin (BIF or SMI) and Chlorfenapyr (CFP or FMI). The initial dosing at 0 wash (W0) is approximately 7g/kg of BIF and 8g/kg of CFP, resulting at a fabric weight of 35 g/sqm to an initial Al content of 245 mg/sqm BIF and 280 mg/sqm CFP. After 20x washing (W20), the residual CFP in the filaments is significantly lower than the residual BIF. CFP is considered a fast-migrating insecticide (FMI) and BIF is considered a slow-migrating insecticide (SMI).

• Fig 11 shows a graph in wash resistance index (WRI) of an insecticidal incorporated mosquito net containing 2 insecticides and using filaments produced in mono-component technology with optimized volume- to surface ratio to accommodate the different migration characteristics of FMI and SMI. 80% of the filaments contributing to the net fabric surface come from GB1 in 100

Denier thickness, while 20% of the filaments contributing to the fabric net surface come from GB 2 in 200 Denier thickness. The average thickness is consequentlyl20D, the fabric weight is 35 g/sqm and the initial insecticidal content is the same as in Fig. 10 of 245 mg/sqm BIF and 280 mg/sqm CFP. The concentrations of BIF and CFP are however adjusted to accommodate the individual migration capabilities of the different insecticides:

GB1 : 80% linear contribution, 100D

. BIF : 9 g/kg

. CFP : 6 g/kg

GB2 : 20% linear contribution, 200D

• BIF : 3g/kg

. CFP : 12g/kg

It is visible in the illustrated graph that after 20Wash, that this optimized embedding of Al in the filaments is leading to a higher residual of CFP in comparison to CFP residual in fig 10, which is leading consequently to an extended product life or potential cost saving.

• Fig 12 shows a graph in Wash resistance index (WRI) of an insecticidal incorporated mosquito net. All filaments are produced in bi-component technology core/sheath design with a ratio of 80%/20% and have identical thickness (120Denier). The weight of the fabric is 35 g/sqm. The average initial Al concentration at W0 of the two different insecticides, Bifenthrin (BIF) and Chlorfenapyr (CFP) of approximately 7 g/kg of BIF and 8g/kg of CFP. This is resulting at a fabric weight of 35 g/sqm to an initial Al content of 245 mg/qm BIF and 280 mg/qm CFP, same as Fig. 10 and 11.

After 20x washing (W20), the residual CFP (or FMI) in the filaments is higher than the residual BIF (SMI). The WRI graphs of both AIs are almost parallel. This is observed, because the CFP, the FMI is predominantly, but not exclusively located in the core of the filament which is causing a delay in release due to longer average travel distance to the filament surface. BIF, the SMI, is located predominantly, but not exclusively in the sheath of the filament with shorter travel distance to the filament surface. This invention equalizes WIR of two AIs with different migration characteristics and therefore enables cost saving and/or performance and/or significantly improved lifetime of the product.

The aforementioned exemplary illustrations serve to illustrate the inventions merit and its working; however, they shall not be construed to limit the invention. Temperatures are given in degrees Celsius; mixing ratios of matters in grams.

Claims

CLAIMS:

1. An insecticidal fabric, knitted from two cylindrical monofilaments (designated as MFI and MF2), containing atleast two active ingredients (designated as All and AI2) and the active ingredients are embedded in different blending ratios in both monofilaments (Fig 1) optionally containing a synergist (SYN).

2. An insecticidal fabric according to claim- 1, wherein the both monofilaments have different diameters (Fig 2).

3. An insecticidal fabric according to claim-2, whereby the diameter is ranging between 25% - 75% larger than diameter of other one.

4. An insecticidal fabric, knitted from two cylindrical monofilaments (designated as MFI and MF2), containing at least two active ingredients (designated as All and AI2) and the active ingredients are embedded in different blending ratios in both monofilaments (Fig 1) containing a synergist (SYN) embedded into at least one monofilament (Fig 1).

5. An insecticidal fabric, knitted from two monofilaments (MFI and MF2), wherein the two active ingredients (All and AI2) are embedded in different blending ratios in both monofilaments and MFI is produced by mono-component technology while MF2 is produced in Bi-Co technology using a core and sheath design, while the AIs of MFI are homogenously distributed within the volume of the filament, and the AIs in MF2 are predominantly, but not exclusively concentrated in the sheath (Fig 3)while Synergist and/or Migration inhibitor is predominantly, but not exclusively used in the core.

6. An insecticidal fabric according to claim-5, whereby the Bi-Co Monofilament has a Core: Sheath Volume ratio ranging between 70% - 95% and 5 - 30% v/v.

7. An insecticidal fabric according to claim-5, wherein the two monofilaments are Bi-Co monofilaments in core and sheath design (Fig 4), the two active ingredients (All and AI2) are embedded in different blending ratios in both monofilaments and the All is mainly but not exclusively concentrated in the sheath of MFI, whileAI2 is mainly but not exclusively concentrated in the sheath of MF2, wherein if active ingredient AI2 is a pyrethroid, then MF2 optionally contain a synergist (SYN) and/or migration inhibitor (MI), which are mainly, but not exclusively concentrated in the core of MF2.

8. An insecticidal fabric according to claim-7, whereby the synergist and migration inhibitor is in one Bi-Co Monofilament is exclusively embedded in the Core of the filament.

9. An insecticidal fabric according to claim-5, whereby MFI contributes between 50-90% and MF2 between 10-50% in filament length to the fabric surface.

10. An insecticidal fabric according to claim- 1, whereby All is a non-pyrethroid insecticide and AI2 is pyrethroid or non-pyrethroid insecticide.

11. An insecticidal fabric according to claim- 10, wherein the non-pyrethroid insecticide selected from Chlorfenapyr, Indoxacarb, Fenpyroximate, Emamectin benzoate, Tolfenpyrad, Metaflumyzone, Spinosad, Cyazofamid or mixtures thereof.

12. An insecticidal fabric according to claim- 10, wherein the combined non-pyrethroid insecticide content in core and sheath together is ranging between 0.2-3.0% w/w.

13. An insecticidal fabric, according to claim- 10, wherein the pyrethroid insecticide is Alpha-

Cypermethrin, Deltamethrin, Bifenthrin, Lambda -cyhalothrin, Permethrin, Etofenprox or mixture thereof.

14. An insecticidal fabric, according to claim-13, wherein the combined pyrethroid insecticide content in core and sheath together is ranging between 0.2-3.0 percent.

15. An insecticidal fabric, according to claim-4, whereby the synergist is PBO, wherein the synergist content in the core and sheath is ranging between 0.2 - 3% w/w.