Insecticidal polymeric compositions, methods and uses

Abstract

An additive composition for addition to a polymeric material, the additive composition comprising an insecticide synergist, a compatibilizer and an absorbent agent.

Description

[0001] Compositions, Uses and Methods

[0002] Field

[0003] The present invention relates to additive compositions comprising insecticide synergists and to uses and methods for improving the properties of the additive compositions. The invention also relates to polymeric materials and to the incorporation of the additive compositions, and optionally insecticides, into the polymeric materials. The additive compositions may be used in the preparation of products, such as long-lasting insecticidal nets, for providing a barrier against insects.

[0004] Background

[0005] Insects may cause infections in humans and animals that they bite. For example, mosquitoes can cause malaria, which is a life-threatening disease. Methods and products for providing a barrier against insects (and therefore for preventing bites by insects such as mosquitoes) are well known. These may use a physical barrier to stop insects contacting and biting a person or animal and / or a chemical barrier which incorporates an insecticide. Insecticides may act by killing insects that contact it, or by means of a knock-down effect or by a repellent effect.

[0006] One preferred method is to use a long-lasting insecticidal net (LLIN). A LLIN is a net that is treated with an insecticide and which has long-lasting performance. The desired long-lasting performance is for a LLIN to last for a period of use of 3 years or more without requiring any further treatment for a number (such as 20) of standard washes. Typically, a LLIN is prepared from a polymeric material (such as polyester or polyethylene) onto or into which the insecticide is loaded. A LLIN typically provides a controlled release of the insecticide to enable the desired longevity. Preferably a LLIN is treated with a low dose of insecticide in order to limit exposure of the user to the insecticide and other chemicals present, and also to minimise costs.

[0007] In addition to an insecticide, LLINs typically also comprise an insecticide synergist which acts to improve the efficacy of the insecticide. Common insecticide synergists are piperonyl butoxide (PBO) and n-octyl bicycloheptane dicarboximide. It is also desirable to provide a controlled release of the insecticide synergist from a LLIN.

[0008] Many LLINs that are currently available do not provide a chemical barrier for the desired 3 year period, and provide only a physical barrier once the chemical barrier is inactive. Additionally, there are difficulties associated with the processing of polymeric materials from which the LLINs are prepared when they include an insecticide synergist, particularly with processing in a manner that meets the necessary cost constraints. For example, if an insecticide synergist is added directly to a polymeric monofilament, the monofilaments are typically difficult to process. If an insecticide synergist is added to a polymeric material as a component of a traditional masterbatch, it is difficult to achieve a high loading of the insecticide synergist, which means that high amounts of the masterbatch are needed and costs increase. The difficulties encountered can lead to undesirable leakage of the insecticide synergist from the LLIN prior to and during use, which leads to reduced performance times.

[0009] Currently the most common LLINs include PBO and a pyrethroid insecticide (such as Alphacyphermethrin or Deltamethrin), in which the PBO acts as a synergist to boost the efficacy of the pyrethroid insecticide. These LLINs are very effective at killing resistant mosquito strains and in combatting malaria. However, PBO is volatile and is often readily released from the net, such that after 1 to 2 years most of the PBO can be depleted.

[0010] Additionally, when PBO is used as the insecticide synergist, this can present a processing challenge. It is desirable to formulate masterbatches that include high amounts of PBO to ensure effectiveness and longevity of the LLIN. However, when PBO is formulated in a liquid masterbatch the PBO can act as a lubricant causing screw slipping during processing.

[0011] If PBO is formulated in a solid masterbatch the PBO is known to leak from the solid masterbatch (during and after preparation of the masterbatch) at a range of loadings. This leakage results in a short shelf life of the solid masterbatches containing PBO and higher production costs.

[0012] Attempts to overcome the problems associated with leakage of insecticide synergists have included incorporating higher loadings initially, but this is undesirable due to increased exposure to chemicals and increased costs.

[0013] It is an object of the present invention to address the above-described problems.

[0014] It is thus an object of the present invention to improve the retention and / or loading of an insecticide synergist in a masterbatch and in a polymeric material from which a product (such as a fibre, for example a monofilament, or a net, for example a LLIN) is prepared, and to improve the longevity of the synergistic activity therein. It is also an object of the present invention to improve the processability of an insecticide synergist into a polymeric material from which a product (such as a fibre, for example a monofilament, or a net, for example a LLIN) is prepared. It is also an object of the present invention to control the release of an insecticide synergist from a masterbatch and from a polymeric material from which a product (such as a fibre, for example a monofilament, or a net, for example a LLIN) is prepared. Summary of the Invention

[0015] According to aspects of the present invention, there is provided a use, method and additive composition as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and from the description which follows.

[0016] According to a first aspect of the invention, there is provided an additive composition for addition to a polymeric material, the additive composition comprising an insecticide synergist, a compatibilizer and an absorbent agent.

[0017] According to a second aspect of the invention, there is provided a method of preparing an additive composition for addition to a polymeric material, the method comprising admixing an insecticide synergist, a compatibilizer and an absorbent agent.

[0018] According to a third aspect of the invention, there is provided an insecticidal formulation comprising an insecticide synergist, a compatibilizer, an absorbent agent and an insecticide.

[0019] According to a fourth aspect of the invention, there is provided a method of preparing an insecticidal formulation, the method comprising admixing an insecticide synergist, a compatibilizer, an absorbent agent and an insecticide.

[0020] According to a fifth aspect of the invention, there is provided a method of preparing polymeric material having one or more of an insecticide synergist, a compatibilizer and an absorbent agent (preferably an insecticide synergist, a compatibilizer and an absorbent agent) incorporated therein, the method comprising:

[0021] (i) selecting a polymeric material;

[0022] (ii) contacting the polymeric material with one or more of the insecticide synergist, the compatibilizer and the absorbent agent (preferably with the insecticide synergist, the compatibilizer and the absorbent agent); and

[0023] (iii) melt-processing the polymeric material.

[0024] According to a sixth aspect of the invention, there is provided a method of preparing polymeric material having one or more of an insecticide synergist, a compatibilizer and an absorbent agent (preferably an insecticide synergist, a compatibilizer and an absorbent agent) and an insecticide incorporated therein, the method comprising:

[0025] (i) selecting a polymeric material;

[0026] (ii) contacting the polymeric material with one or more of the insecticide synergist , the compatibilizer and the absorbent agent (preferably with the insecticide synergist, the compatibilizer and the absorbent agent) and with the insecticide; and (iii) melt-processing the polymeric material.

[0027] According to a seventh aspect of the invention, there is provided a polymeric material, wherein the polymeric material incorporates one or more of an insecticide synergist, a compatibilizer and an absorbent agent.

[0028] According to an eighth aspect of the invention, there is provided a product comprising the polymeric material according to the seventh aspect.

[0029] According to a ninth aspect of the invention, there is provided a method of producing a fibre, the method comprising incorporating one or more of an insecticide synergist, a compatibilizer and an absorbent agent (preferably an insecticide synergist, a compatibilizer and an absorbent agent) into a polymeric material and forming the resultant polymeric material into a fibre.

[0030] According to a tenth aspect of the invention, there is provided a use of a polymeric material incorporating one or more of an insecticide synergist, a compatibilizer and an absorbent agent (preferably an insecticide synergist, a compatibilizer and an absorbent agent) to form a fibre.

[0031] According to an eleventh first aspect of the invention, there is provided a method of producing a net, especially a LLIN, the method comprising incorporating one or more of an insecticide synergist, a compatibilizer and an absorbent agent (preferably an insecticide synergist, a compatibilizer and an absorbent agent) into a polymeric material and forming the resultant polymeric material into a fibre, followed by forming one or more of the fibres into the net, especially the LLIN.

[0032] According to a twelfth aspect of the invention, there is provided a use of a polymeric material incorporating one or more of an insecticide synergist, a compatibilizer and an absorbent agent (preferably an insecticide synergist, a compatibilizer and an absorbent agent) to form a net, especially a LLIN.

[0033] According to a thirteenth aspect of the invention, there is provided a method of increasing the loading and / or the retention of an insecticide synergist in an additive composition comprising the insecticide synergist, the method comprising contacting the insecticide synergist with a compatibilizer and / or an absorbent agent in the additive composition.

[0034] According to a fourteenth aspect of the invention, there is provided a use of a compatibilizer and / or an absorbent agent to increase the loading and / or the retention of an insecticide synergist in an additive composition comprising the insecticide synergist. According to a fifteenth aspect of the invention, there is provided a method of controlling the release of an insecticide synergist from an additive composition comprising the insecticide synergist, the method comprising contacting the insecticide synergist with a compatibilizer and / or an absorbent agent in the additive composition.

[0035] According to a sixteenth aspect of the invention, there is provided a use of a compatibilizer and / or an absorbent agent to control the release of an insecticide synergist from an additive composition comprising the insecticide synergist.

[0036] According to a seventeenth aspect of the invention, there is provided a use of an insecticidal formulation according to the fourth aspect, a polymeric material according to the seventh aspect or a product according to the eighth aspect (for example a net, such as a LLIN) to kill insects.

[0037] According to an eighteenth aspect of the invention, there is provided a method of killing insects, the method comprising contacting the insects with an insecticidal formulation according to the fourth aspect, a polymeric material according to the seventh aspect or a product according to the eighth aspect (for example a net, such as a LLIN) to kill insects.

[0038] According to a nineteenth aspect of the invention, there is provided an assembly comprising:

[0039] (a) an extruder for extruding polymeric material;

[0040] (b) a receptacle containing an additive composition according to the first aspect or an insecticide formulation according to the third aspect; and

[0041] (c) addition means operatively connected to the receptacle for adding the additive composition or the insecticide formulation from the receptacle into the polymeric material, for example in or downstream of the extruder.

[0042] Any feature of any aspect of the invention described herein may be combined with any feature of any other aspect described herein mutatis mutandis.

[0043] Detailed Description of the Invention

[0044] According to a first aspect of the invention, there is provided an additive composition for addition to a polymeric material, the additive composition comprising an insecticide synergist, a compatibilizer and an absorbent agent.

[0045] The additive composition of the first aspect is typically added to a polymeric material. For example, the additive composition is typically added to a polymeric material so as to incorporate the insecticide synergist into the polymeric material. The additional components of the additive composition, including the compatibilizer and the absorbent agent, will also be incorporated into the polymeric material along with the insecticide synergist.

[0046] The additive composition comprises an insecticide synergist. The term “insecticide synergist” is used in its ordinary sense, which is well-known to those skilled in the art. Specifically, it refers to a composition or compound that acts to enhance the effectiveness of an insecticide, but which does not have any substantive insecticidal activity itself.

[0047] The additive composition of the first aspect may comprise any suitable insecticide synergist. The additive composition of the first aspect may comprise one or more suitable insecticide synergists, including mixtures of two or more insecticide synergists. The insecticide synergist may be selected from one or more of piperonyl butoxide (PBO) and n-octyl bicycloheptane dicarboximide. Preferably the insecticide synergist is PBO.

[0048] The additive composition of the first aspect may comprise the insecticide synergist in any suitable amount, such as in an amount of from 5 to 30 wt%, for example from 10 to 30 wt% or from 10 to 25 wt%, wherein the wt% is based on the total weight of the composition.

[0049] The additive composition comprises a compatibilizer. By a compatibilizer we mean a compound that promotes the miscibility (for example solubility) between two phases in the additive composition and thereby enhances the retention of the insecticide synergist in the additive composition.

[0050] The additive composition may comprise any suitable compatibilizer.

[0051] The additive composition of the first aspect may comprise one or more suitable compatibilizers, including mixtures of two or more compatibilizers.

[0052] Preferably, the compatibilizer is a non-reactive compatibilizer.

[0053] Examples of suitable compatibilizers may include waxes.

[0054] The compatibilizer may be a polymeric compatibilizer, such as a copolymer compatibilizer.

[0055] The additive composition of the first aspect may comprise one or more suitable polymeric compatibilizers, including mixtures of two or more polymeric compatibilizers. Preferably, the compatibilizer may be a copolymer compatibilizer. The copolymer compatibilizer may comprise any suitable copolymer. By a copolymer we mean the product of the polymerisation of at least two different monomers.

[0056] The additive composition of the first aspect may comprise one or more suitable copolymer compatibilizers, including mixtures of two or more copolymer compatibilizers.

[0057] Suitable copolymer compatibilizers may have a weight average molecular weight (Mw) of from 10,000 to 500,000 Da. The Mw as reported herein is measured by gel permeation chromatography according to ASTM D6579-11 .

[0058] Suitable copolymer compatibilizers may have a melt flow rate of from 0.2 to 30 g / min, preferably from 0.2 to 25 g / 10 min, measured at 190°C in accordance with ISO 1133.

[0059] Suitable copolymer compatibilizers may have a softening point of up to 95°C, such as from 30 to 95°C or from 30 to 90°C or from 30 to 70°C, for example from 30 to 45°C or from 35 to 40°C, wherein the softening point is measured in accordance with Japanese Standards Association method JIS K 7206.

[0060] Suitable copolymer compatibilizers may have a melting point of less than 130°C, suitably of less than 105°C, such as from 65 to 130°C, preferably from 65 to 95°C, wherein the melting point is measured in accordance with Japanese Standards Association method JIS K 7121 .

[0061] Examples of suitable copolymer compatibilizers include ethylene-based copolymers, for example copolymers obtained by copolymerising ethylene and one or more additional monomers (also referred to as an ethylene copolymer). Examples of suitable additional monomers include acrylic monomers, vinyl acetate, vinyl chloride and maleic anhydride.

[0062] By an acrylic monomer we mean one or more suitable alkyl(alk)acrylate or (alk)acrylic acid monomers. Examples of such suitable monomers include methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, methacrylic acid, acrylic acid, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-butyl methacrylate, iso-butyl methacrylate, t-butyl methacrylate, 2-ethylhexy methacrylate, 2-ethylhexyl acrylate, lauryl methacrylate, lauryl acrylate, cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl acrylate, isobornyl methacrylate. Hydroxyl- functional alkyl(alk)acrylates may also be used, such as hydroxyethyl methacrylate and hydroxypropyl methacrylate. Preferred alkyl(alk)acrylate or (alk)acrylic acid monomers may include methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, methacrylic acid and acrylic acid.

[0063] Preferably, the additional monomer may be selected from one or more acrylic monomers, maleic anhydride and vinyl acetate. More preferably, the additional monomer may be selected from one or more of methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, methacrylic acid, acrylic acid, maleic anhydride and vinyl acetate. Even more preferably, the additional monomer may be selected from one or more of methyl acrylate, methacrylic acid, maleic anhydride and vinyl acetate.

[0064] Preferably, the additional monomer may be selected from one or more acrylic monomers and vinyl acetate. More preferably, the additional monomer may be selected from one or more of methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, methacrylic acid, acrylic acid and vinyl acetate. Even more preferably, the additional monomer may be selected from one or more of methyl acrylate, methacrylic acid and vinyl acetate.

[0065] Preferred examples of suitable copolymer compatibilizers include copolymers obtained by copolymerising ethylene and one or more additional monomers selected from acrylic monomers, maleic anhydride, vinyl chloride and vinyl acetate, such as selected from methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, methacrylic acid, acrylic acid, maleic anhydride, vinyl chloride and vinyl acetate, preferably selected from methyl acrylate, methacrylic acid, maleic anhydride, vinyl chloride and vinyl acetate.

[0066] Further preferred examples of suitable copolymer compatibilizers include copolymers obtained by copolymerising ethylene and one or more additional monomers selected from acrylic monomers, maleic anhydride and vinyl acetate, such as selected from methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, methacrylic acid, acrylic acid, maleic anhydride and vinyl acetate, preferably selected from methyl acrylate, methacrylic acid, maleic anhydride and vinyl acetate.

[0067] Further preferred examples of suitable copolymer compatibilizers include copolymers obtained by copolymerising ethylene and one or more additional monomers selected from acrylic monomers and vinyl acetate, such as selected from methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, methacrylic acid, acrylic acid and vinyl acetate, preferably selected from methyl acrylate, methacrylic acid and vinyl acetate.

[0068] Examples of suitable copolymer compatibilizers include, for example, copolymers obtained by copolymerising ethylene and one or more additional monomers such as maleic anhydride, acrylic acid, vinyl acetate and / or vinyl chloride. Preferred examples of suitable copolymer compatibilizers include copolymers of ethylene and vinyl acetate (EVA copolymers), copolymers of ethylene and methyl acrylate (EMA copolymer), and copolymers of ethylene and maleic anhydride.

[0069] When the compatibilizer is an ethylene copolymer, the copolymer may contain any suitable proportion of the additional monomers(s). Suitably, the ethylene copolymer may have a content of additional monomer(s) of from 0.1 to 40 wt%, for example from 5 to 40 wt%, preferably from 15 to 35 wt% or from 15 to 30 wt%, wherein the wt% is based on the total weight of the copolymer.

[0070] For example, a suitable ethylene copolymer may contain from 60 to 99.9 % by weight of repeat units derived from ethylene and from 0.1 to 40 % by weight of repeat units derived from the additional monomers(s), wherein the wt% is based on the total weight of the copolymer. For example, a suitable ethylene copolymer may contain from 65 to 85 % by weight of repeat units derived from ethylene and from 15 to 35 % by weight of repeat units derived from the additional monomers(s), wherein the wt% is based on the total weight of the copolymer. More preferably, the ethylene copolymer may contain from 70 to 85 % by weight of repeat units derived from ethylene and from 15 to 30 % by weight of repeat units derived from the additional monomers(s), wherein the wt% is based on the total weight of the copolymer.

[0071] Preferred examples of suitable copolymer compatibilizers include copolymers of ethylene and vinyl acetate (EVA copolymers) and copolymers of ethylene and maleic anhydride.

[0072] A preferred copolymer compatibilizer is a copolymer of ethylene and methyl acrylate (EMA copolymer).

[0073] Suitable EMA copolymers may comprise any suitable proportion of methyl acrylate. Suitably, the EMA copolymer may have a methyl acrylate content of from 2 to 40 wt%, such as from 15 to 35 wt% or from 15 to 30 wt%, wherein the wt% is based on the total weight of the copolymer.

[0074] The EMA copolymer may comprise any suitable proportion of ethylene. Suitably, the EMA copolymer may have an ethylene content of from 60 to 98 wt%, such as from 65 to 85 wt% or from 70 to 85 wt%, wherein the wt% is based on the total weight of the copolymer.

[0075] More preferably, the EMA copolymer may contain from 65 to 85 % by weight of repeat units derived from ethylene and from 15 to 35 % by weight of repeat units derived from methyl acrylate. Even more preferably, the EMA copolymer may contain from 70 to 85 % by weight of repeat units derived from ethylene and from 15 to 30 % by weight of repeat units derived from methyl acrylate. Suitably, the EMA copolymer may have a weight average molecular weight (Mw) of from 50,000 to 300,000 Da. The Mw as reported herein is measured by ASTM D6579-11 .

[0076] Suitably, the EMA copolymer may have a melt flow rate of from 0.2 to 25 g / 10 min, preferably from 0.2 to 15 g / 10 min, measured at 190°C in accordance with ISO 1 133.

[0077] Suitably, the EMA copolymer may have a softening point of up to 95°C, such as from 30 to 90°C or from 30 to 70°C, wherein the softening point is measured in accordance with Japanese Standards Association method JIS K 7206.

[0078] Suitably, the EMA copolymer may have a melting point of less than 105°C, such as from 65 to 100°C, wherein the melting point is measured in accordance with Japanese Standards Association method JIS K 7121 .

[0079] Preferably, the compatibilizer comprises an EMA copolymer. More preferably, the EMA copolymer consists essentially of or consists of ethylene and methyl acrylate (i.e. the EMA copolymer is obtained by copolymerising monomers consisting essentially of or consisting of ethylene and methyl acrylate).

[0080] A preferred copolymer compatibilizer is a copolymer of ethylene and vinyl acetate (an EVA copolymer).

[0081] Suitable EVA copolymers may comprise any suitable proportion of vinyl acetate. Suitably, the EVA copolymer may have a vinyl acetate content of from 2 to 40 wt%, such as from 15 to 35 wt% or from 15 to 30 wt%, wherein the wt% is based on the total weight of the copolymer.

[0082] The EVA copolymer may comprise any suitable proportion of ethylene. Suitably, the EVA copolymer may have an ethylene content of from 60 to 98 wt%, such as from 65 to 85 wt% or from 70 to 85 wt%, wherein the wt% is based on the total weight of the copolymer.

[0083] More preferably, the EVA copolymer may contain from 65 to 85 % by weight of repeat units derived from ethylene and from 15 to 35 % by weight of repeat units derived from vinyl acetate. Even more preferably, the EVA copolymer may contain from 70 to 85 % by weight of repeat units derived from ethylene and from 15 to 30 % by weight of repeat units derived from vinyl acetate.

[0084] Suitably, the EVA copolymer may have a weight average molecular weight (Mw) of from 250,000 to 500,000 Da. The Mw as reported herein is measured by ASTM D6579-11 . Suitably, the EVA copolymer may have a melt flow rate of from 0.2 to 25 g / 10 min measured at 190°C in accordance with ISO 1133.

[0085] Suitably, the EVA copolymer may have a softening point of up to 95°C, such as from 30 to 90°C or from 30 to 70°C, for example from 30 to 45°C or from 35 to 40°C, wherein the softening point is measured in accordance with Japanese Standards Association method JIS K 7206.

[0086] Suitably, the EVA copolymer may have a melting point of less than 105°C, such as from 65 to 95°C, wherein the melting point is measured in accordance with Japanese Standards Association method JIS K 7121 .

[0087] Preferably, the compatibilizer comprises an EVA copolymer. More preferably, the EVA copolymer consists essentially of or consists of ethylene and vinyl acetate (i.e. the EVA copolymer is obtained by copolymerising monomers consisting essentially of or consisting of ethylene and vinyl acetate).

[0088] A preferred copolymer compatibilizer is a copolymer of ethylene and methacrylic acid (EMAA copolymer).

[0089] Suitable EMAA copolymers may comprise any suitable proportion of methacrylic acid. Suitably, the EMAA copolymer may have a methacrylic acid content of from 2 to 40 wt%, such as from 15 to 35 wt% or from 15 to 30 wt%, wherein the wt% is based on the total weight of the copolymer.

[0090] The EMAA copolymer may comprise any suitable proportion of ethylene. Suitably, the EMAA copolymer may have an ethylene content of from 60 to 98 wt%, such as from 65 to 85 wt% or from 70 to 85 wt%, wherein the wt% is based on the total weight of the copolymer.

[0091] More preferably, the EMAA copolymer may contain from 65 to 85 % by weight of repeat units derived from ethylene and from 15 to 35 % by weight of repeat units derived from methacrylic acid. Even more preferably, the EMAA copolymer may contain from 70 to 85 % by weight of repeat units derived from ethylene and from 15 to 30 % by weight of repeat units derived from methacrylic acid.

[0092] Suitably, the EMAA copolymer may have a weight average molecular weight (Mw) of from 10,000 to 60,000 Da. The Mw as reported herein is measured by ASTM D6579-11 .

[0093] Suitably, the EMAA copolymer may have a melt flow rate of from 0.2 to 30 g / 10 min, such as from 0.2 to 25 g / 10 min, measured at 190°C in accordance with ISO 1 133. Suitably, the EMAA copolymer may have a softening point of up to 95°C, such as from 30 to 90°C or from 30 to 70°C, wherein the softening point is measured in accordance with Japanese Standards Association method JIS K 7206.

[0094] Suitably, the EMAA copolymer may have a melting point of less than 105°C, such as from 65 to 100°C, wherein the melting point is measured in accordance with Japanese Standards Association method JIS K 7121 .

[0095] Preferably, the compatibilizer comprises an EMAA copolymer. More preferably, the EMAA copolymer consists essentially of or consists of ethylene and methacrylic acid (i.e. the EMAA copolymer is obtained by copolymerising monomers consisting essentially of or consisting of ethylene and methacrylic acid).

[0096] A preferred copolymer compatibilizer is a copolymer of ethylene and maleic anhydride.

[0097] Suitable copolymers of ethylene and maleic anhydride may comprise any suitable proportion of maleic anhydride. Suitably, the copolymer of ethylene and maleic anhydride may have a maleic anhydride content of from 0.1 to 40 wt%, wherein the wt% is based on the total weight of the copolymer.

[0098] The copolymer of ethylene and maleic anhydride may comprise any suitable proportion of ethylene. Suitably, the copolymer of ethylene and maleic anhydride may have an ethylene content of from 60 to 99.1 wt%, wherein the wt% is based on the total weight of the copolymer.

[0099] More preferably, the copolymer of ethylene and maleic anhydride may contain from 60 to 99.9 % by weight of repeat units derived from ethylene and from 0.1 to 40 % by weight of repeat units derived from maleic anhydride.

[0100] Suitably, the copolymer of ethylene and maleic anhydride may have a weight average molecular weight (Mw) of from 50,000 to 500,000 Da. The Mw as reported herein is measured by ASTM D6579-11 .

[0101] Suitably, the copolymer of ethylene and maleic anhydride may have a melt flow rate of from 0.2 to 25 g / 10 min, preferably from 0.2 to 15 g / 10 min, measured at 190°C in accordance with ISO 1133.

[0102] Suitably, the copolymer of ethylene and maleic anhydride may have a softening point of up to 95°C, such as from 30 to 95°C, wherein the softening point is measured in accordance with Japanese Standards Association method JIS K 7206. Suitably, the copolymer of ethylene and maleic anhydride may have a melting point of less than 130°C, such as from 65 to 130°C, wherein the melting point is measured in accordance with Japanese Standards Association method JIS K 7121 .

[0103] Preferably, the compatibilizer comprises a copolymer of ethylene and maleic anhydride. More preferably, the copolymer of ethylene and maleic anhydride consists essentially of or consists of ethylene and maleic anhydride (i.e. the copolymer of ethylene and maleic anhydride is obtained by copolymerising monomers consisting essentially of or consisting of ethylene and maleic anhydride).

[0104] Suitable ethylene copolymers are typically commercially available. Examples of such commercially available copolymers include Versalis Greenflex HN 70 (EVA), Versalis Greenflex ML 50, DOW ELVALOY AC 1330, DOW ELVALOY AC 1218, DOW BYNEL 4157 and DOW NUCREL 925 (as set out in the Examples section).

[0105] The additive composition of the first aspect may comprise the compatibilizer in any suitable amount, such as in an amount of from 5 to 50 wt%, for example from 15 to 40 wt% or from 15 to 35 wt%, wherein the wt% is based on the total weight of the composition.

[0106] The additive composition of the first aspect comprises an absorbent agent. The absorbent agent may absorb or encapsulate the insecticide synergist, such as PBO. The additive composition may comprise any suitable absorbent agent. The additive composition of the first aspect may comprise one or more suitable absorbent agents, including mixtures of two or more absorbent agents. The absorbent agent may absorb or encapsulate the insecticide synergist upon contact therewith. The absorption or encapsulation of the insecticide synergist by the absorbent agent is believed to advantageously enable control of the release of the insecticide synergist from the additive composition and from any polymeric material in which it is incorporated.

[0107] The absorbent agent may be an inorganic absorbent agent or an organic absorbent agent.

[0108] A suitable absorbent agent may be selected from one or more of activated alumina, calcium oxide, a clay, a clay silicate, a zeolite and a silica.

[0109] Other suitable absorbent agents include metal-organic frameworks.

[0110] The absorbent agent may have an average particle size of 25 |j.m or less, such as 20 |j.m or less, or 15 |j.m or less. For example, the absorbent agent may an average particle size of from 0.5 to 25 |j.m, such as from 0.5 to 20 |j.m, or from 0.5 to 15 |j.m. The average particle size may be measured according to a standard method known in the art, such as according to ISO 3310-1 . During preparation of the additive composition, the absorbent agent may undergo processing to decrease the particle size thereof. For example, the absorbent agent may have an average particle size of 5 |j.m or less, such as from 0.5 to 5 |j.m.

[0111] The absorbent agent may comprise calcium carbonate. Suitably the calcium carbonate may have an average particle size of from 0.1 to 25 |j.m, for example from 0.1 to 20 |j.m or from 0.1 to 15 |j.m, preferably from 0.1 to 10 |j.m. Suitably the calcium carbonate may have a specific surface area of from 8000 to 30,000 cm2 / g.

[0112] The absorbent agent may comprise a silica. The silica may have a specific surface area of from 100 to 1000 m2 / g.

[0113] The specific surface area may be determined by BET surface area analysis.

[0114] The absorbent agent may be modified to provide desirable properties in use. For example the absorbent agent may comprise a coating, such as a hydrophobic surface coating. A hydrophobic surface coating may improve the compatibility of the absorbent agent with an insecticide synergist such as PBO and thereby increase the capability of the absorbent agent to absorb the insecticide synergist, such as PBO.

[0115] The additive composition of the first aspect may comprise the absorbent agent in any suitable amount, such as in an amount of from 1 to 10 wt%, for example from 1 to 8 wt%, wherein the wt% is based on the total weight of the composition.

[0116] Preferably, the additive composition of the first aspect comprises PBO, a compatibilizer and an absorbent agent.

[0117] Preferably, the additive composition of the first aspect comprises PBO, a polymeric compatibilizer (such as a copolymer compatibilizer) and an absorbent agent.

[0118] Preferably, the additive composition of the first aspect comprises PBO, an EVA copolymer and an absorbent agent.

[0119] Preferably, the additive composition of the first aspect comprises PBO, a polymeric compatibilizer (such as a copolymer compatibilizer) and a silica based absorbent agent.

[0120] Preferably, the additive composition of the first aspect comprises PBO, an EVA copolymer and a silica based absorbent agent. Preferably, the additive composition of the first aspect comprises PBO, a polymeric compatibilizer (such as a copolymer compatibilizer) and calcium carbonate.

[0121] Preferably, the additive composition of the first aspect comprises PBO, an EVA copolymer and calcium carbonate.

[0122] The additive composition of the first aspect may comprise any suitable further component(s).

[0123] For example, the additive composition of the first aspect may further comprise a carrier. The additive composition may comprise any suitable carrier. Typically, the carrier is compatible with the polymeric material to which the additive composition is to be added. For example the carrier is typically compatible with a polymeric material from which a fibre, such as a monofilament, or a net, such as a LLIN, may be prepared. Typically, the carrier is inert and is not intended to react with any components of the additive composition.

[0124] The carrier may comprise a polymeric material, such as a thermoplastic polymer. The carrier (when present) may comprise a polyolefin. The carrier may comprise mixtures of two or more different polyolefins.

[0125] A suitable polyolefin for use as a carrier may for example comprise polyethylene (for example HDPE, LDPE or LLDPE), polypropylene, or a mixture thereof. Preferably, the carrier is LLDPE.

[0126] The additive composition of the first aspect may comprise the carrier (when present) in any suitable amount, such as in an amount of 75 wt% or less, for example from 25 to 75 wt%, or preferably from 40 to 70 wt%, wherein the wt% is based on the total weight of the composition.

[0127] For example, the additive composition of the first aspect may further comprise a polymer processing aid. The additive composition may comprise any suitable polymer processing aid. Suitable polymer processing aids may include lubricants and fluoropolymer-based additives.

[0128] For example, the additive composition of the first aspect may further comprise a stabilizer, such as an antioxidant or UV stabilizer.

[0129] Preferably, the additive composition of the first aspect may comprise: from 10 to 30 wt% of an insecticide synergist; from 5 to 50 wt% of a compatibilizer; from 1 to 10 wt% of an absorbent agent; and from 25 to 75 wt% of a carrier; wherein the wt% is based on the total weight of the composition. Preferably, the additive composition of the first aspect may comprise: from 10 to 25 wt% of an insecticide synergist; from 15 to 35 wt% of a compatibilizer; from 1 to 8 wt% of an absorbent agent; and from 40 to 70 wt% of a carrier; wherein the wt% is based on the total weight of the composition.

[0130] Preferably, the additive composition of the first aspect comprises PBO, a compatibilizer, an absorbent agent and a carrier.

[0131] Preferably, the additive composition of the first aspect comprises PBO, a polymeric compatibilizer (such as a copolymer compatibilizer), an absorbent agent and a carrier.

[0132] Preferably, the additive composition of the first aspect comprises PBO, an EVA copolymer, an absorbent agent and a carrier.

[0133] Preferably, the additive composition of the first aspect comprises PBO, a polymeric compatibilizer (such as a copolymer compatibilizer), a silica based absorbent agent and a carrier.

[0134] Preferably, the additive composition of the first aspect comprises PBO, an EVA copolymer, a silica based absorbent agent and a carrier.

[0135] Preferably, the additive composition of the first aspect comprises PBO, a polymeric compatibilizer (such as a copolymer compatibilizer), calcium carbonate and a carrier.

[0136] Preferably, the additive composition of the first aspect comprises PBO, an EVA copolymer, calcium carbonate and a carrier.

[0137] Preferably, the additive composition of the first aspect comprises PBO, a polymeric compatibilizer (such as a copolymer compatibilizer), an absorbent agent and a polyolefin carrier (such as HDPE or LLDPE, preferably LLDPE).

[0138] Preferably, the additive composition of the first aspect comprises PBO, an EVA copolymer, an absorbent agent and a polyolefin carrier (such as HDPE or LLDPE, preferably LLDPE).

[0139] Preferably, the additive composition of the first aspect comprises PBO, a polymeric compatibilizer (such as a copolymer compatibilizer), a silica based absorbent agent and a polyolefin carrier (such as HDPE or LLDPE, preferably LLDPE). Preferably, the additive composition of the first aspect comprises PBO, an EVA copolymer, a silica based absorbent agent and a polyolefin carrier (such as HDPE or LLDPE, preferably LLDPE).

[0140] Preferably, the additive composition of the first aspect comprises PBO, a polymeric compatibilizer (such as a copolymer compatibilizer), calcium carbonate and a polyolefin carrier (such as HDPE or LLDPE, preferably LLDPE).

[0141] Preferably, the additive composition of the first aspect comprises PBO, an EVA copolymer, calcium carbonate and a polyolefin carrier (such as HDPE or LLDPE, preferably LLDPE).

[0142] Preferably, the additive composition of the first aspect comprises PBO, an EMA copolymer, an absorbent agent and a carrier.

[0143] Preferably, the additive composition of the first aspect comprises PBO, an EMA copolymer, a silica based absorbent agent and a carrier.

[0144] Preferably, the additive composition of the first aspect comprises PBO, an EMA copolymer, calcium carbonate and a carrier.

[0145] Preferably, the additive composition of the first aspect comprises PBO, an EMA copolymer, an absorbent agent and a polyolefin carrier (such as HDPE or LLDPE, preferably LLDPE).

[0146] Preferably, the additive composition of the first aspect comprises PBO, an EMA copolymer, a silica based absorbent agent and a polyolefin carrier (such as HDPE or LLDPE, preferably LLDPE).

[0147] Preferably, the additive composition of the first aspect comprises PBO, an EMA copolymer, calcium carbonate and a polyolefin carrier (such as HDPE or LLDPE, preferably LLDPE).

[0148] The additive composition of the first aspect may be an additive masterbatch.

[0149] The additive composition of the first aspect may be a solid composition, such as a solid additive masterbatch.

[0150] Preferably, unless otherwise stated herein, the reference to “liquid” and “solid” refer to a state at 25°C and standard pressure (101325Pa). The additive composition of the first aspect may be a solid composition in any suitable form, such as in the form of pellets or granules, especially pellets.

[0151] The additive composition of the first aspect may comprise a wax, such as a paraffin wax, a microwax and / or a synthetic wax. Preferably however when the additive composition comprises a wax, the wax is present in a low amount, such as an amount of 2 wt% or less wherein the wt% is based on the total weight of the composition.

[0152] The additive composition of the first aspect may preferably be substantially or completely free of waxes, such as paraffin waxes, microwaxes and synthetic waxes.

[0153] The additive composition of the first aspect may be incorporated into a polymeric material, i.e. such that the polymeric material contains the components of the additive composition.

[0154] The additive composition is intended to be used in combination with an insecticide, so that in use of the additive composition the insecticide synergist therein may act to increase the effectiveness of the insecticide with which it is combined. The additive composition may be combined with an insecticide by any suitable means. For example, the additive composition of the first aspect may further comprise an insecticide, i.e. such that the insecticide and the insecticide synergist are included in the same composition and added to the polymeric material by means of addition of the additive composition thereto. Alternatively, the insecticide may be contained in a separate composition to the additive composition of the first aspect, whereby both the additive composition and the composition containing the insecticide are each added to the polymeric material, and the insecticide synergist and the insecticide are so combined upon addition to the polymeric material.

[0155] Thus, the additive composition of the first aspect is intended for use in the preparation of a chemical barrier composition that comprises an insecticide.

[0156] The additive composition of the first aspect is typically intended for use in the preparation of an insecticidal formulation that comprises an insecticide, for example which insecticidal formulation will act as a chemical barrier to insects. The chemical barrier is typically comprised in a net, such as a LLIN, which is used to provide a barrier against insects.

[0157] According to a second aspect of the invention, there is provided a method of preparing an additive composition for addition to a polymeric material, the method comprising admixing an insecticide synergist, a compatibilizer and an absorbent agent. In the method of the second aspect, the additive composition may be an additive composition according to the first aspect.

[0158] Preferred features of second aspect are as defined in relation to the first aspect

[0159] In the second aspect, the insecticide synergist, the compatibilizer and the absorbent agent may be admixed using any suitable mixing means.

[0160] The method of the second aspect may further comprise a treatment step to provide the additive composition in a desired form. For example, the treatment step may comprise melt-processing, such as melt blending or melt extrusion, followed by conversion into pellets or granules by means known to persons skilled in the art. Preferably, the method of the second aspect may comprise melt-extruding the mixture of the insecticide synergist, the compatibilizer and the absorbent agent and forming the extruded mixture in to pellets.

[0161] The melt-processing may be undertaken in an apparatus (e.g. a melt processing apparatus such as an extruder) operating at a maximum temperature of less than 200°C, or less than 170°C.

[0162] The additive composition of the first aspect may be combined with an insecticide to provide an insecticidal composition.

[0163] According to a third aspect of the invention, there is provided an insecticidal formulation comprising an insecticide synergist, a compatibilizer, an absorbent agent and an insecticide.

[0164] In the insecticidal formulation of the third aspect, the insecticide synergist, the compatibilizer and the absorbent agent may be comprised in an additive composition, such as an additive composition according to the first aspect. Thus, the third aspect may provide an insecticidal formulation comprising an additive composition of the first aspect and at least one insecticide. In other words, the additive composition of the first aspect may be combined with an insecticide to provide the insecticidal formulation of the third aspect. The insecticide may be comprised in an insecticidal additive composition, such as an insecticidal masterbatch, which may be combined with the additive composition of the first aspect to provide the insecticidal formulation.

[0165] Alternatively, in the insecticidal formulation of the third aspect, the insecticide synergist, the compatibilizer, the absorbent agent and the insecticide may be comprised in a single additive composition, which may be an additive masterbatch. In this case, the insecticidal formulation of the third aspect may comprise an additive composition that comprises an insecticide in addition to an insecticide synergist, a compatibilizer and an absorbent agent. This additive composition may be provided for addition to a polymeric material. The insecticidal formulation of the third aspect may act as a chemical barrier to insects. The chemical barrier is typically comprised in a net, such as a LLIN, which is used to provide a barrier against insects.

[0166] Preferred features of third aspect, especially in relation to the insecticide synergist, the compatibilizer and the absorbent agent, are as defined in relation to the first aspect.

[0167] The term insecticide is used is used in its ordinary sense, which is well-known to those skilled in the art. Specifically, it refers to substances used to prevent, destroy, repel and / or mitigate insects.

[0168] The insecticidal formulation of the third aspect may comprise any suitable insecticide. The insecticidal formulation of the third aspect may comprise one or more suitable insecticides, including mixtures of two or more insecticides.

[0169] Suitable insecticides may include pyrethrin and pyrethroid insecticides. Examples of pyrethroid insecticides include the following:

[0170] Acrinathrin

[0171] Allethrin d-cis-trans Allethrin d-trans Allethrin

[0172] Bifenthrin

[0173] Bioallethrin

[0174] Bioallethrin S-cyclopentenyl

[0175] Bioresmethrin

[0176] Cycloprothrin

[0177] Cyfluthrin beta-Cyfluthrin

[0178] Cyhalothrin lambda-Cyhalothrin gamma-Cyhalothrin

[0179] Cypermethrin alpha-Cypermethrin beta-Cypermethrin theta-Cypermethrin zeta-Cypermethrin

[0180] Cyphenothrin [(1 R)-trans- isomers]

[0181] Deltamethrin

[0182] Empenthrin [(EZ)- (1 R)- isomers] Esfenvalerate

[0183] Etofenprox

[0184] Fenpropathrin

[0185] Fenvalerate

[0186] Flucythrinate

[0187] Flumeth rin tau-Fluvalinate

[0188] Kadethrin

[0189] Pyrethrins (pyrethrum)

[0190] Halfenprox

[0191] Phenothrin [(1 R)-trans- isomer]

[0192] Prallethrin

[0193] Resmethrin

[0194] Silafluofen

[0195] Tefluthrin

[0196] Tetrameth rin

[0197] Tetramethrin [(1 R)- isomers]

[0198] Tralomethrin

[0199] Transfluthrin

[0200] Permethrin

[0201] A preferred pyrethroid insecticide is cypermethrin, such as alpha-cypermethrin.

[0202] Examples of suitable insecticides may include cypermethrin, deltamethrin, permethrin, fenvalerate, cypermethrin, bifenthrin, resmethrin, sumethrin, n-octyl bicycloheptene dicarboximide, / V, / V-diethyl-mefa-toluamide (DEET), picaridin, 3-[N-butyl-N-acetyl]- aminopropionic acid, dimethyl carbate (and mixtures thereof).

[0203] The insecticidal formulation of the third aspect may comprise one or more suitable additional components, for example selected from one or more of a carrier, a polymer processing aid and an additional compatibilizer (including mixtures thereof).

[0204] For example, the insecticidal formulation of the third aspect may further comprise a carrier. The insecticidal formulation may comprise any suitable carrier. For example the carrier may be as disclosed above in relation to the first aspect. Typically, the carrier is compatible with the polymeric material to which the insecticidal formulation is to be added. For example the carrier is typically compatible with a polymeric material from which a fibre, such as a monofilament, or a net, such as a LLIN, may be prepared. Typically, the carrier is inert and is not intended to react with any components of the insecticidal formulation. The insecticidal formulation of the third aspect may comprise the insecticide in any suitable amount, such as in an amount of from 10 to 25 wt%, wherein the wt% is based on the total weight of the insecticidal formulation.

[0205] The insecticidal formulation of the third aspect may comprise the insecticide in an amount of from 10 to 25 wt% and the additive composition of the first aspect in an amount of from 5 to 25 wt%, such as from 5 to 15 wt%, wherein the wt% is based on the total weight of the insecticidal formulation.

[0206] The insecticidal formulation of the third aspect may comprise the insecticide synergist in an amount of from 10 to 25 wt%, the compatibilizer in an amount of from 15 to 30 wt%, the absorbent agent in an amount of from 1 to 10 wt% and the insecticide in an amount of from 10 to 25 wt%, wherein the wt% is based on the total weight of the insecticidal formulation.

[0207] The insecticidal formulation of the third aspect may comprise the insecticide synergist in an amount of from 10 to 25 wt%, the compatibilizer in an amount of from 15 to 30 wt%, the absorbent agent in an amount of from 1 to 10 wt%, the carrier in an amount of from 40 to 75 wt% and the insecticide in an amount of from 10 to 25 wt%, wherein the wt% is based on the total weight of the insecticidal formulation.

[0208] According to a fourth aspect of the invention, there is provided a method of preparing an insecticidal formulation, the method comprising admixing an insecticide synergist, a compatibilizer, an absorbent agent and an insecticide.

[0209] The method of the fourth aspect may be used to prepare an insecticide formulation according to the third aspect of the invention.

[0210] In the method of the fourth aspect, the insecticide synergist, the compatibilizer and the absorbent agent may be comprised in an additive composition and the method of the fourth aspect may comprise the step of preparing the additive composition by admixing the insecticide synergist, the compatibilizer and the absorbent agent.

[0211] In the method of the fourth aspect, the insecticide synergist, the compatibilizer and the absorbent agent may be comprised in an additive composition according to the first aspect and the method of the fourth aspect may comprise the step of preparing the additive composition according to the first aspect by admixing the insecticide synergist, the compatibilizer and the absorbent agent. The method of preparing the additive composition may be as set out for the second aspect. The method of the fourth aspect may then additionally comprise the step of admixing the additive composition with an insecticide.

[0212] In the method of the fourth aspect, the insecticide may be contained in an insecticidal additive composition, such as an insecticidal masterbatch, such that the method of the fourth aspect may comprise admixing an insecticidal additive composition, such as an insecticidal masterbatch, with an additive composition (for example an additive masterbatch), such as an additive composition according to the first aspect. Optional additional components may additionally be admixed with the insecticidal additive composition (for example insecticidal masterbatch) and the additive composition (for example an additive masterbatch) as discussed herein. The admixing may be conducted using any suitable mixing means.

[0213] The method of the fourth aspect may further comprise a treatment step to provide the insecticidal formulation in a desired form. For example, the treatment step may comprise melt-processing, such as melt blending or melt extrusion, followed by conversion into pellets or granules by means known to persons skilled in the art. Preferably, the method of the fourth aspect may comprise melt-extruding the mixture of the insecticide synergist, the compatibilizer, the absorbent agent and the insecticide, and forming the extruded mixture in to pellets.

[0214] The melt-processing may be undertaken in an apparatus (e.g. a melt processing apparatus such as an extruder) operating at a maximum temperature of less than 200°C, or less than 170°C.

[0215] Preferred features of fourth aspect, especially in relation to the insecticide synergist, the compatibilizer, the absorbent agent and the insecticide, are as defined in relation to the first and third aspects.

[0216] The insecticidal formulation may be incorporated into a polymeric material, i.e. such that the polymeric material contains the components of the insecticidal formulation.

[0217] The insecticidal formulation may be prepared prior to or during addition to a polymeric material.

[0218] According to a fifth aspect of the invention, there is provided a method of preparing polymeric material having one or more of an insecticide synergist, a compatibilizer and an absorbent agent (preferably an insecticide synergist, a compatibilizer and an absorbent agent) incorporated therein, the method comprising:

[0219] (i) selecting a polymeric material;

[0220] (ii) contacting the polymeric material with one or more of the insecticide synergist, the compatibilizer and the absorbent agent (preferably with the insecticide synergist, the compatibilizer and the absorbent agent); and (iii) melt-processing the polymeric material.

[0221] According to a sixth aspect of the invention, there is provided a method of preparing polymeric material having one or more of an insecticide synergist, a compatibilizer and an absorbent agent (preferably an insecticide synergist, a compatibilizer and an absorbent agent) and an insecticide incorporated therein, the method comprising:

[0222] (i) selecting a polymeric material;

[0223] (ii) contacting the polymeric material with one or more of the insecticide synergistthe compatibilizer and the absorbent agent (preferably with the insecticide synergist, the compatibilizer and the absorbent agent) and with the insecticide; and

[0224] (ii) melt-processing the polymeric material.

[0225] Preferably the method of the fifth aspect of the invention is for preparing polymeric material having an insecticide synergist, a compatibilizer and an absorbent agent incorporated therein, the method comprising:

[0226] (i) selecting a polymeric material;

[0227] (ii) contacting the polymeric material with the insecticide synergist, the compatibilizer and the absorbent agent; and

[0228] (iii) melt-processing the polymeric material.

[0229] Preferably the method of the sixth aspect of the invention provides a method of preparing polymeric material having an insecticide synergist, a compatibilizer, an absorbent agent and an insecticide incorporated therein, the method comprising:

[0230] (i) selecting a polymeric material;

[0231] (ii) contacting the polymeric material with the insecticide synergist, the compatibilizer, the absorbent agent and the insecticide; and

[0232] (iii) melt-processing the polymeric material.

[0233] In the method of the fifth or sixth aspect, any of the insecticide synergist, the compatibilizer, the absorbent agent and the insecticide, when present, may be contacted with the polymeric material in any suitable order and in any suitable means.

[0234] Preferably the method of the fifth aspect incorporates an insecticide synergist, a compatibilizer and an absorbent agent into the polymeric material.

[0235] Preferably the method of the sixth aspect incorporates an insecticide synergist, a compatibilizer, an absorbent agent and an insecticide into the polymeric material. References herein to contacting the insecticide synergist, the compatibilizer, the absorbent agent and, when present, the insecticide, with the polymeric materials are intended to mean contacting with one or more, but preferably with all, of the insecticide synergist, the compatibilizer, the absorbent agent, and with the insecticide, when present (i.e. in relation to the sixth aspect).

[0236] In the method of the fifth or sixth aspect, the insecticide synergist, the compatibilizer, the absorbent agent and, when present, the insecticide, may be contacted with the polymeric material in any suitable order and in any suitable means. For example, the insecticide synergist, the compatibilizer, the absorbent agent and, when present, the insecticide may each be added to (and thereby contacted with) the polymeric material individually in any suitable order, or they may be added to (and thereby contacted with) the polymeric material together in any suitable combination. For example, in one example, the insecticide synergist and the absorbent agent may be added to the polymeric material together, followed by the compatibilizer and, when present, the insecticide (for example wherein the compatibilizer and insecticide may be added together).

[0237] In the method of the fifth or sixth aspect, the insecticide synergist, the compatibilizer and the absorbent agent may be comprised in an additive composition (for example an additive masterbatch), such as an additive composition according to the first aspect. Thus, the methods may comprise the selection and / or the preparation of an additive composition, such as an additive composition according to a first aspect, and contacting the additive composition with the polymeric material. The additive composition may have any feature of the additive composition of the first aspect and / or may be made as described in accordance with the second aspect.

[0238] In the method of the sixth aspect, the insecticide synergist, the compatibilizer and the absorbent agent may be comprised in an additive composition (for example an additive masterbatch), such as an additive composition according to the first aspect and the insecticide may be contacted with the polymeric material separately. Thus, the method of the sixth aspect may comprise the selection and / or the preparation of an additive composition, such as an additive composition according to a first aspect, and contacting the additive composition and the insecticide with the polymeric material. The additive composition may have any feature of the additive composition of the first aspect and / or may be made as described in accordance with the second aspect.

[0239] Alternatively, in the method of the sixth aspect the insecticide may be comprised in an additive composition that additionally comprises the insecticide. Thus, the method of the sixth aspect may comprise contacting the polymeric material with an additive composition comprising the insecticide synergist, the compatibilizer, the absorbent agent and the insecticide. Alternatively, in the method of the sixth aspect the insecticide may be comprised in an insecticidal additive composition, such as an insecticidal masterbatch. Thus, the method of the sixth aspect may comprise contacting the polymeric material with an additive composition comprising the insecticide synergist, the compatibilizer and the absorbent agent and with an insecticidal additive composition comprising the insecticide. In this case the additive composition and the insecticidal additive composition may be added to the polymeric material simultaneously.

[0240] Alternatively, in the method of the sixth aspect the insecticide may be comprised in an insecticidal formulation, such as an insecticidal formulation according to the third aspect. Thus, the method of the sixth aspect may comprise contacting the polymeric material with an insecticidal formulation according to the third aspect.

[0241] Preferred features of fifth and sixth aspects, especially in relation to the insecticide synergist, the compatibilizer, the absorbent agent and the insecticide, are as defined in relation to the first to fourth aspects.

[0242] Any suitable polymeric material may be used in the methods of the fifth and sixth aspects. Suitably, the polymeric material is a material that can be formed into fibres. Preferably, the polymeric material is compatible with (such as the same as or structurally similar to) the carrier or additional carrier comprised in the additive composition or the insecticidal formulation (when present).

[0243] Suitably, the polymeric material may comprise a polyolefin. A suitable polyolefin may for example comprise polyethylene (for example HDPE, LDPE or LLDPE), polypropylene, or a mixture thereof. More preferably, the polymeric material comprises HDPE.

[0244] Preferably, the polymeric material, the carrier and the additional carrier (when all present) each comprise a polyolefin.

[0245] The method may include contacting the polymeric material with from 0.5 to 3.0 wt% of the insecticide synergist, for example via an additive composition (such as the additive composition of the first aspect), wherein the wt% is based on the total weight of the polymeric material (i.e. in which the insecticide synergist is incorporated).

[0246] The method may include contacting the polymeric material with from 0.2 to 4.0 wt% of the compatibilizer, for example via an additive composition (such as the additive composition of the first aspect), wherein the wt% is based on the total weight of the polymeric material (i.e. in which the compatibilizer is incorporated). The method may include contacting the polymeric material with from 0.08 to 1.25 wt% of the absorbent agent, for example via an additive composition (such as the additive composition of the first aspect), wherein the wt% is based on the total weight of the polymeric material (i.e. in which the absorbent agent is incorporated).

[0247] The method may include contacting the polymeric material with from 0.1 to 2.0 wt% of the insecticide, for example via an additive composition or via an insecticidal additive composition (such as the additive composition of the first aspect or the insecticidal additive composition of the third aspect), wherein the wt% is based on the total weight of the polymeric material (i.e. in which the insecticide is incorporated).

[0248] Preferably the method of the fifth aspect incorporates an insecticide synergist, a compatibilizer and an absorbent agent into the polymeric material, wherein the polymeric material comprises the insecticide synergist, the compatibilizer and the absorbent agent in a combined amount of from 0.78 to 8.25 wt%, wherein the wt% is based on the total weight of the polymeric material (i.e. in which the insecticide synergist, the compatibilizer and the absorbent agent are incorporated).

[0249] Preferably the method of the sixth aspect incorporates an insecticide synergist, a compatibilizer, an absorbent agent and an insecticide into the polymeric material, wherein the polymeric material comprises the insecticide synergist, the compatibilizer, the absorbent agent and the insecticide in a combined amount of from 0.88 to 10.25 wt%, wherein the wt% is based on the total weight of the polymeric material (i.e. in which the insecticide synergist, the compatibilizer, the absorbent agent and the insecticide are incorporated).

[0250] The insecticide synergist, the compatibilizer, the absorbent agent and the insecticide (when present) may be contacted with the polymeric material when the polymeric material is in a molten state. In other words, the insecticide synergist, the compatibilizer, the absorbent agent and the insecticide (when present) are preferably dosed into the polymeric material when the polymeric material is in a molten state.

[0251] The polymeric material may be melted in an extruder and the insecticide synergist, the compatibilizer, the absorbent agent and the insecticide (when present) may be contacted with the polymeric material in the extruder or downstream thereof. A mixing means is suitably provided for facilitating mixing of the insecticide synergist, the compatibilizer, the absorbent agent and the insecticide (when present) with the polymeric material. The mixing means may be provided by using either static or dynamic mixers. Downstream of the point of contact of the polymeric material with the insecticide synergist, the compatibilizer, the absorbent agent and the insecticide (when present), there may be spinning means for spinning the polymeric material to define fibres. The same general set up could be used to make other products from the polymeric material, for example sheets or films wherein the means of exit would be through the relevant die heads.

[0252] The polymeric material which is contacted in the methods of the fifth and sixth aspects may be supplied directly from a reactor in which the polymeric material is made in a polymerisation reaction. Thus, the polymeric material used suitably does not comprise pellets or granules or other isolated polymeric material but suitably comprises molten polymeric material from a polymerisation reactor which is coupled to apparatus for contacting the polymeric material with the insecticide synergist, the compatibilizer, the absorbent agent and the insecticide (when present).

[0253] For example, the insecticide synergist, the compatibilizer, the absorbent agent and the insecticide (when present) may be added to the polymeric material during the melt-processing step.

[0254] The melt-processing may comprise melt blending or melt extrusion.

[0255] The melt-processing may preferably be undertaken in an apparatus (e.g. a melt processing apparatus such as an extruder or moulding apparatus such as an injection or rotational moulding apparatus) operating at a maximum temperature of less than 200°C, or less than 170°C. Preferably, the melt-processing is carried out in an extruder, for example a single or twin-screw extruder. The screw rotation speed should provide adequate mixing, and will depend on the screw and barrel design.

[0256] The melt-processing of the polymeric material may occur prior to and / or during the contacting step (ii).

[0257] The method of the fifth and sixth aspects of the invention may further comprise the step of forming a fibre (such as a monofilament), wherein the fibre is formed downstream of the point of contact of the insecticide synergist, the compatibilizer, the absorbent agent, and optionally the insecticide, with the polymeric material. Thus, the method may comprise spinning the polymeric material which includes the insecticide synergist, the compatibilizer, the absorbent agent and the insecticide (when present) to produce a fibre (such as a monofilament). The fibre may be a continuous length of fibre, for example of greater than 5 m or 10 m.

[0258] The method may include delivery of the polymeric material into an extruder directly from a reactor in which the polymeric material is produced. The fibres may be formed using any suitable method, such as using a spinning device for the spinning the polymeric material to define fibres. Such a spinning device is typically located downstream of the point of contact of the polymeric material with the insecticide synergist, the compatibilizer, the absorbent agent, and optionally the insecticide.

[0259] According to a seventh aspect of the invention, there is provided a polymeric material, wherein the polymeric material incorporates one or more of an insecticide synergist, a compatibilizer and an absorbent agent.

[0260] The seventh aspect may preferably provide a polymeric material, wherein the polymeric material incorporates an insecticide synergist, a compatibilizer and an absorbent agent.

[0261] The seventh aspect may provide a polymeric material, wherein the polymeric material incorporates one or more of an insecticide synergist and a compatibilizer.

[0262] Preferably the polymeric material according to the seventh aspect incorporates one or more of an insecticide synergist and a compatibilizer.

[0263] Preferably the polymeric material according to the seventh aspect incorporates an insecticide synergist and a compatibilizer.

[0264] Preferably, the polymeric material according to the seventh aspect further incorporates an insecticide.

[0265] The seventh aspect may preferably provide a polymeric material, wherein the polymeric material incorporates an insecticide synergist, a compatibilizer, an absorbent agent and an insecticide.

[0266] Preferred features of the seventh aspect, especially in relation to the insecticide synergist, the compatibilizer, the absorbent agent, the insecticide and the polymeric material, are as defined in relation to the first to sixth aspects.

[0267] The polymeric material of the seventh aspect may comprise from 0.25 to 3.0 wt% of the insecticide synergist, wherein the wt% is based on the total weight of the polymeric material (i.e. in which the insecticide synergist is incorporated).

[0268] The polymeric material of the seventh aspect may comprise from 0.2 to 4.0 wt%, such as from 0.25 to 4.0 wt%, of the compatibilizer, wherein the wt% is based on the total weight of the polymeric material (i.e. in which the compatibilizer is incorporated). The polymeric material of the seventh aspect may comprise from 0.08 to 1 .25 wt% of the absorbent agent, wherein the wt% is based on the total weight of the polymeric material (i.e. in which the absorbent agent is incorporated).

[0269] The polymeric material of the seventh aspect may comprise from 0.1 to 2.0 wt% of the insecticide, wherein the wt% is based on the total weight of the polymeric material (i.e. in which the insecticide is incorporated).

[0270] Preferably the polymeric material of the seventh aspect comprises an insecticide synergist, a compatibilizer and an absorbent agent in a combined amount of from 0.78 to 8.25 wt%, wherein the wt% is based on the total weight of the polymeric material (i.e. in which the insecticide synergist, the compatibilizer and the absorbent agent are incorporated).

[0271] Preferably the polymeric material of the seventh aspect comprises an insecticide synergist, a compatibilizer, an absorbent agent and an insecticide in a combined amount of from 0.88 to 10.25 wt%, wherein the wt% is based on the total weight of the polymeric material (i.e. in which the insecticide synergist, the compatibilizer, the absorbent agent and the insecticide are incorporated).

[0272] Preferably, the polymeric material of the seventh aspect comprises more than 75 wt%, preferably more than 80 wt%, more preferably more than 85 wt%, of polymeric material, with the remaining components as disclosed herein incorporated therein and wherein the wt% is based on the total weight of the polymeric material.

[0273] Preferably in the seventh aspect, the polymeric material may comprise a polyolefin. A suitable polyolefin may for example comprise polyethylene (for example HDPE, LDPE or LLDPE), polypropylene, or a mixture thereof. More preferably, the polymeric material comprises HDPE.

[0274] Preferably, the polymeric material of the seventh aspect comprises more than 75 wt%, preferably more than 80 wt%, more preferably more than 85 wt%, of a polyolefin, with the remaining components as disclosed herein incorporated therein and wherein the wt% is based on the total weight of the polymeric material.

[0275] Methods of detecting and optionally measuring the amount of the insecticide synergist, compatibilizer, absorbent agent and insecticide (when present) would be well known to persons skilled in the art and may vary depending on the specific components used. For example, the compatibilizer may be detected and measured using well known techniques such as FTIR, DSC and NMR. The insecticide synergist, absorbent agent and insecticide may, for example, be detected and measured by the method of polymer dissolution followed by ICP-MS or LCMS. The polymeric material of the seventh aspect may be formed into any suitable product.

[0276] According to an eighth aspect of the invention, there is provided a product comprising the polymeric material according to the seventh aspect. The product may be made from the polymeric material according to the seventh aspect.

[0277] Suitably, the product comprises a structure provided with an insecticide synergist, a compatibilizer, an absorbent agent and an optionally insecticide incorporated therein. More suitably, the product comprises a structure provided with the additive composition according to the first aspect and optionally an insecticide incorporated therein.

[0278] The product may be in any suitable form, such as in the form of a fibre, gauze, net, cloth, screen, grid or fabric.

[0279] The product of the eighth aspect may be a fibre, especially a monofilament.

[0280] The product of the eighth aspect may be a net, especially a LLIN. For example, the net may be formed from one or more fibres, especially one or more monofilaments, described herein. The net may be a mosquito repellent net.

[0281] According to a ninth aspect of the invention, there is provided a method of producing a fibre, the method comprising incorporating one or more of an insecticide synergist, a compatibilizer and an absorbent agent (preferably an insecticide synergist, a compatibilizer and an absorbent agent) into a polymeric material and forming the resultant polymeric material into a fibre.

[0282] The ninth aspect of the invention may preferably provide a method of producing a fibre, the method comprising incorporating an insecticide synergist, a compatibilizer and an absorbent agent into a polymeric material and forming the resultant polymeric material into a fibre.

[0283] In the method of the ninth aspect, the polymeric material may be formed into a fibre using any suitable means, which would be well known to persons skilled in the art. For example, the fibres may be formed downstream of the point of contact of the polymeric material with the insecticide synergist, the compatibilizer, the absorbent agent and the insecticide (when present), and the fibres may be formed by spinning means for spinning the polymeric material to define fibres.

[0284] According to a tenth aspect of the invention, there is provided a use of a polymeric material incorporating one or more of an insecticide synergist, a compatibilizer and an absorbent agent (preferably an insecticide synergist, a compatibilizer and an absorbent agent) to form a fibre. The tenth aspect of the invention may preferably provide a use of a polymeric material incorporating an insecticide synergist, a compatibilizer and an absorbent agent to form a fibre.

[0285] According to an eleventh aspect of the invention, there is provided a method of producing a net, especially a LLIN, the method comprising incorporating one or more of an insecticide synergist, a compatibilizer and an absorbent agent (preferably an insecticide synergist, a compatibilizer and an absorbent agent) into a polymeric material and forming the resultant polymeric material into a fibre, followed by forming one or more of the fibres into the net, especially the LLIN.

[0286] The eleventh aspect of the invention may preferably provide a method of producing a net, especially a LLIN, the method comprising incorporating an insecticide synergist, a compatibilizer and an absorbent agent into a polymeric material and forming the resultant polymeric material into a fibre, followed by forming one or more of the fibres into the net, especially the LLIN.

[0287] According to a twelfth aspect of the invention, there is provided a use of a polymeric material incorporating one or more of an insecticide synergist, a compatibilizer and an absorbent agent (preferably an insecticide synergist, a compatibilizer and an absorbent agent) to form a net, especially a LLIN.

[0288] The twelfth aspect of the invention may preferably provide a use of a polymeric material incorporating an insecticide synergist, a compatibilizer and an absorbent agent to form a net, especially a LLIN.

[0289] In the method of the ninth or eleventh aspect, the insecticide synergist, compatibilizer and absorbent agent may be incorporated into the polymeric material as components of the additive composition according to the first aspect. Thus, the ninth aspect of the invention may provide a method of producing a fibre, the method comprising incorporating an additive composition of the first aspect into a polymeric material and forming the resultant polymeric material into a fibre. The eleventh aspect of the invention may provide a method of producing a net, especially a LLIN, the method comprising incorporating an additive composition of the first aspect into a polymeric material and forming the resultant polymeric material into a fibre, followed by forming one or more of the fibres into the net, especially the LLIN.

[0290] In the use of the tenth or twelfth aspect, the insecticide synergist, compatibilizer and absorbent agent may be incorporated into the polymeric material as components of the additive composition according to the first aspect. Thus, the tenth aspect of the invention may provide the use of a polymeric material incorporating an additive composition according to the first aspect to form a fibre. The twelfth aspect of the invention may provide the use of a polymeric material incorporating an additive composition according to the first aspect to form a net, especially a LLIN.

[0291] The method of the ninth or eleventh aspect may further comprise incorporating an insecticide into the polymeric material. Thus, the method of the ninth or eleventh aspect may further comprise incorporating an insecticide into the polymeric material and forming the resultant polymeric material into a fibre. For example, the insecticide synergist, compatibilizer, absorbent agent and insecticide may be incorporated into the polymeric material as components of the insecticidal formulation according to the third aspect.

[0292] In the use according to the tenth or twelfth aspect, the polymeric material may further incorporate an insecticide. Thus, the use of the tenth or twelfth aspect may further comprise incorporating an insecticide into the polymeric material. Thus, the use of the tenth or twelfth aspect may further comprise incorporating an insecticide into the polymeric material and forming the resultant polymeric material into a fibre. For example, the insecticide synergist, compatibilizer, absorbent agent and insecticide may be incorporated into the polymeric material as components of the insecticidal formulation according to the third aspect.

[0293] Preferred features of eighth to twelfth aspects, especially in relation to the insecticide synergist, the compatibilizer, the absorbent agent, the insecticide and the polymeric material, are as defined in relation to the first to seventh aspects.

[0294] According to a thirteenth aspect of the invention, there is provided a method of increasing the loading and / or the retention of an insecticide synergist in an additive composition comprising the insecticide synergist, the method comprising contacting the insecticide synergist with a compatibilizer and / or an absorbent agent in the additive composition.

[0295] According to a fourteenth aspect of the invention, there is provided a use of a compatibilizer and / or an absorbent agent to increase the loading and / or the retention of an insecticide synergist in an additive composition comprising the insecticide synergist.

[0296] Thus, the compatibilizer and absorbent agent may act in combination to increase the loading and / or the retention of an insecticide synergist in the additive composition

[0297] When the compatibilizer and the absorbent agent are used in the fourteenth aspect, by increasing the loading of an insecticide synergist we mean that more of the insecticide synergist can be included in the additive composition when the compatibilizer and / or the absorbent agent are present compared to the same additive composition with only one of a compatibilizer or an absorbent agent. When the compatibilizer or the absorbent agent are used in the fourteenth aspect, by increasing the loading of an insecticide synergist we mean that more of the insecticide synergist can be included in the additive composition compared to the same additive composition with no compatibilizer or absorbent agent.

[0298] By increasing the loading of an insecticide synergist in the additive composition, this in turn increases the loading of the insecticide synergist in the insecticidal formulation and in the polymeric material, thus improving the action of the chemical barrier in a product prepared from the polymeric material, such as a fibre (for example monofilament) or net (for example LLIN).

[0299] Thus, the present invention also provides a method of increasing the loading and / orthe retention of an insecticide synergist in an insecticidal formulation or polymeric material (or product formed therefrom) comprising the insecticide synergist, the method comprising contacting the insecticide synergist with a compatibilizer and / or an absorbent agent in the insecticidal formulation or polymeric material.

[0300] Thus, the present invention also provides the use of a compatibilizer and / or an absorbent agent to increase the loading and / or the retention of an insecticide synergist in an insecticidal formulation or polymeric material (or product formed therefrom) comprising the insecticide synergist.

[0301] In the use of the fourteenth aspect, the insecticide synergist is comprised in an additive composition comprising the insecticide synergist, and comprising the compatibilizer and / or the absorbent agent (and optionally a carrier).

[0302] In the use of the fourteenth aspect, the insecticide synergist may be comprised in an additive composition comprising the insecticide synergist, the compatibilizer and the absorbent agent (and optionally a carrier), such as in an additive composition of the first aspect.

[0303] By increasing the retention of the insecticide synergist in the additive composition we mean that the insecticide synergist predominantly remains therein. In particular, we mean that the insecticide synergist remains in the additive composition at 25°C and standard pressure (101325Pa) and is not substantially released from the composition, for example during storage and / or use of the additive composition. For example, after a period of 28 days at 25°C and standard pressure (101325Pa) from 80 to 99 wt% of the insecticide synergist may be retained in the additive composition.

[0304] Suitably, when the compatibilizer and the absorbent agent are used in the fourteenth aspect more of the insecticide synergist remains (or is retained) in the additive composition when the compatibilizer and / or the absorbent agent are present compared to the same additive composition with only one of a compatibilizer or an absorbent agent. Suitably, when the compatibilizer or the absorbent agent are used in the fourteenth aspect, more of the insecticide synergist remains (or is retained) in the additive composition when the compatibilizer or the absorbent agent are present compared to the same additive composition with no compatibilizer or absorbent agent.

[0305] For example, for an additive composition comprising 20 wt% of the insecticide synergist, the amount of insecticide synergist that is released from the composition upon storage at 25°C and standard pressure (101325Pa) for 1 week may be reduced from about 10 to 15 wt% to substantially zero.

[0306] Improving the retention of the insecticide synergist in the additive composition is advantageous because it increases the shelf-life of the additive composition and / or enables a higher loading of the insecticide synergist therein and / or enables uniform dosages of the insecticide synergist when the additive composition is in use.

[0307] Increasing the loading and / orthe retention ofthe insecticide synergist in the additive composition also leads to an increase of the loading and / or retention of the insecticide synergist in any formulation, polymeric material or product that comprises the additive composition.

[0308] For example, there may be provided a method of increasing the loading and / or the retention of an insecticide synergist in an insecticidal formulation according to the third aspect, in a polymeric material according to the seventh aspect or in a product according to the eighth aspect, the method comprising contacting the insecticide synergist with a compatibilizer and an absorbent agent in the insecticidal formulation, polymeric material or product (for example as a component of the additive composition of the first aspect).

[0309] For example, there may be provided a use of a compatibilizer and an absorbent agent to increase the loading and / or the retention of an insecticide synergist in an insecticidal formulation according to the third aspect, in a polymeric material according to the seventh aspect or in a product according to the eighth aspect (for example as a component of an additive composition of the first aspect).

[0310] Preferred features of thirteenth and fourteenth aspects, especially in relation to the insecticide synergist, the compatibilizer, the absorbent agent and the insecticide, are as defined in relation to the first to seventh aspects.

[0311] According to a fifteenth aspect of the invention, there is provided a method of controlling the release of an insecticide synergist from an additive composition comprising the insecticide synergist, the method comprising contacting the insecticide synergist with a compatibilizer and / or an absorbent agent in the additive composition.

[0312] The method of the fifteenth aspect may comprise contacting the insecticide synergist with a compatibilizer in combination with an absorbent agent.

[0313] According to a sixteenth aspect of the invention, there is provided a use of a compatibilizer and / or an absorbent agent to control the release of an insecticide synergist from an additive composition comprising the insecticide synergist.

[0314] The sixteenth aspect of the invention may provide a use of a compatibilizer in combination with an absorbent agent to control the release of an insecticide synergist from an additive composition comprising the insecticide synergist.

[0315] By controlling the release of the insecticide synergist we mean to increase the time taken for the insecticide synergist to be released from the additive composition, including in use of the additive composition for example when incorporated into a polymeric material or product as disclosed herein.

[0316] In particular, the combination of a compatibilizer and absorbent agent is believed to advantageously enable control of the release of the insecticide synergist from the additive composition and from any polymeric material in which it is incorporated.

[0317] Preferred features of fifteenth and sixteenth aspects, especially in relation to the insecticide synergist, the compatibilizer, the absorbent agent and the insecticide are as defined in relation to the first to seventh aspects.

[0318] According to an seventeenth aspect of the invention, there is provided a use of an insecticidal formulation according to the fourth aspect, a polymeric material according to the seventh aspect (when comprising an insecticide) or a product according to the eighth aspect (for example a net, such as a LLIN) to kill insects.

[0319] According to a eighteenth aspect of the invention, there is provided a method of killing insects, the method comprising contacting the insects with an insecticidal formulation according to the fourth aspect, a polymeric material according to the seventh aspect (when comprising an insecticide) or a product according to the eighth aspect (for example a net, such as a LLIN) to kill insects. Preferred features of seventeenth and eighteenth aspects are as defined in relation to the first to eighth aspects.

[0320] According to a nineteenth aspect, there is provided an assembly comprising:

[0321] (a) an extruder for extruding polymeric material;

[0322] (b) a receptacle containing an additive composition according to the first aspect or an insecticide formulation according to the third aspect; and

[0323] (c) addition means operatively connected to the receptacle for adding the additive composition or the insecticide formulation from the receptacle into the polymeric material, for example in or downstream of the extruder.

[0324] The assembly may further include a polymerisation reactor for producing the polymeric material in a polymerisation reaction, suitably from monomers, the reactor being operatively connected to the extruder for delivering polymeric material from the reactor to the extruder.

[0325] The assembly may further comprise spinning means downstream of the extruder and addition means for receiving polymeric material which has been contacted with the additive composition or the insecticide formulation and spinning the polymeric material to produce fibre.

[0326] Preferred features of nineteenth aspects are as defined in relation to the first to twelfth aspects.

[0327] Brief description of the figures

[0328] For a better understanding of the invention, and to show how exemplary embodiments of the same may be carried into effect, reference will be made, by way of example only, to the accompanying diagrammatic Figures, in which:

[0329] Figure 1 shows an example of a seven-point calibration curve of PBO using the high-resolution mass spectroscopy detector with accurate mass search for peak detection as used in Example 4.

[0330] Specific embodiments of the invention will now be described, by way of example.

[0331] Examples

[0332] Example 1 - Preparation and evaluation of Additive Compositions

[0333] The components set out in Table 1 were added to a glass container and mixed using an IKA mixer at 500 RPM for at least 30 minutes. This provided a white paste - powder like material. This material was then fed into the feeder of a Labtech extruder with a diameter of 25 mm. Temperature profile: 158, 158, 158, 160 °C. 330 RPM were used for the screw and 80 RPM for the feeder. A water bath with circulating water and of 1 meter in length was used for cooling after the die plate. The cooled material was fed into a pelletizer to provide solid pellets.

[0334] Table 1

[0335] *Melt Flow Rate 25 g / 10 min measured at 190°C in accordance with ISO 1133, Vinyl acetate content 28%

[0336] **Average particle size about 20 |j.m; specific surface area 400 to 700 m2 / g.

[0337] The solid pellets produced were then stored in a plastic bag at room temperature (about 25°C) for 6 weeks to assess their stability. After 6 weeks a visual inspection showed that the pellets from Additive Composition 2 showed no PBO liquid was present on the surface of the pellets and no caking was observed at the bottom of the bag. This shows that there was little, if any, release of the PBO from the pellets upon storage. On the contrary, we observed an oily surface on the solid pellets from Additive Composition 1 (which contained no EVA co-polymer) which demonstrated that there was some release of the liquid PBO.

[0338] The amount of PBO in the pellets after storage for 6 weeks at room temperature (about 25°C) was also measured using the following Gas Chromatography (GC) method.

[0339] An extraction liquid was prepared by mixing 940 ml of xylene, 50 ml of 10% citric acid solution in tetrahydrofuran and 10 ml of a standard solution in a 1 litre Schott bottle and sonicating for 15 to 30 minutes. The standard solution was prepared by weighing 1250mg (accurate to 0.1 mg) of dioctyl phthalate into a 100 ml volumetric flask and filling to the 100 ml mark with tetrahydrofuran; followed by sonicating for 5 minutes.

[0340] 500 mg of each of the pellets was added to a 100 ml three-neck flask and 50 ml of the extraction liquid was added. The resultant mixture was then stirred and heated at reflux for 30 minutes at 120 to 125°C. The mixture was then cooled to room temperature in a fume hood. 5 ml of the extraction liquid was removed and added into a 10 ml centrifuge tube and centrifuged at 2000 rpm for 20 minutes. The supernatant was then filtered with a 0.22um filter head before analysis by GC.

[0341] After 6 weeks additive composition 1 of Table 1 showed 17 wt% of PBO therein and additive composition 2 of Table 1 showed 19.5 wt% of PBO therein, showing less leakage of the PBO from the pellets of additive composition 2.

[0342] Example 2 - Preparation and evaluation of Monofilaments

[0343] The components set out in Table 2 were added to a vessel and mixed using a resin pellets mixer at room temperature for 30 minutes. The additive composition type is as set out in Table 1 . The Insecticide masterbatch used comprised Alphacyphermethrin (about 10 wt%) in HDPE.

[0344] The resulting mixture was moved into the feeder of a monofilament (MF) line to prepare monofilaments therefrom. The conditions were: temperature profile of the MF line: 175, 185, 195, 205, 208°C; temperature of the drawing bath: 96°C.; drawing ratio: 7.5.; linear density of the monofilaments: 1 10 Dtex; MF extrusion speed: 110 meters / hour.

[0345] The monofilaments were marked as MF-A and MF-B. These MF were warped and knitted into nets by using Karl Mayer Knitting Machines.

[0346] Table 2

[0347] Washing resistance studies were conducted on the nets as produced above to quantify the PBO releasing rate, using a WHO method for Net washing LITSOP122. Table 3 includes the data from the washing resistance index of PBO for MF-A and MF-B. In summary MF-B net (which contains EVA copolymer) had PBO washing resistance index higher than that of MF-A, suggesting a better controlled or slower releasing rate of PBO in the monofilament. Table 3

[0348] Example 3 - Preparation and evaluation of Monofilaments

[0349] The components set out in Table 4, except the EVA polymer when present, were added to a vessel and mixed using a resin pellets mixer at room temperature for 30 minutes. The resulting mixture and the EVA polymer (when added) was moved into the feeder of a monofilament (MF) line to prepare monofilaments therefrom. The conditions were: temperature profile of the MF line: 175, 185, 195, 205, 208°C; temperature of the drawing bath: 96°C.; drawing ratio: 7.5.; linear density of the monofilaments: 1 10 Dtex; MF extrusion speed: 110 meters / hour.

[0350] The monofilaments were marked as MF-1 and MF-2. These MF were warped and knitted into nets by using Karl Mayer Knitting Machines. Washing resistance studies using a WHO method for Net washing LITSOP122 were conducted on those nets to quantify the PBO releasing rate.

[0351] Washing resistance index of PBO are shown in Table 5. MF-2 nets which contain 4 wt% EVA copolymer have higher WRI than that of MF-1 , which show that the EVA copolymer performs as a compatibilizer for PBO and HDPE and slows down the PBO release rate.

[0352] Table 4

[0353] As set out in Table 1

[0354] ** Masterbatch as used in Example 2

[0355] Table 5 Example 4

[0356] Compositions C1 , C2, C5, C6, C7, C8, C1 1 , C12, C13 and C14 comprising an insecticide synergist and a compatibilizer in the amounts set out in Table 6 were prepared in the form of pellets according to the following method.

[0357] Pellets of polymer were mixed with pellets of compatibilizer using a Congrav OP1 gravimetric feeder to a Prism twin screw (TSE) 24 HC extruder, screws rotating at 150 revolutions per minute. The total output of the extruder was 7kg / hr such that the throughput rate of polymer was 4.9 kg / hour and the throughput rate of compatibilizer was 2.1 kg / hour. The ten heater zones in the extruder were set to maintain the following temperature profile (in °C) from inlet to outlet; 25- 100-155-155-160-160-160-160-160-155. The die of the extruder was set to maintain a temperature of 150°C. In the sixth zone was an injection port through which the insecticide synergist was injected at 1 .3 kg / hour using a ColorMatrix CM1000E pump. A die head pressure (DHP) of about 17 bar and torque of about 49% was found. The resulting polymer strands were drawn along a Cobalt conveyor belt where they were cooled by fans before being fed into a pelletiser set to a length of 2.0 mm. The solid pellets were stored in heat sealed aluminium foil bags.

[0358] Comparative polymeric materials C3 and C4 comprising an insecticide synergist (without compatibilizer) in the amounts set out in Table 5 were prepared in the form of pellets according to the above method but using only polymer in place of the polymer and compatibilizer blend. The addition rate of polymer was 5.25 kg / hour, and the addition rate of inscrticide synergist was 1 .75 kg / hour.

[0359] Polymeric materials C9 and C10 comprising an insecticide synergist, a compatibilizer and an absorbent agent in the amounts set out in Table 5 were prepared in the form of pellets according to the above method but with the addition of the absorbent agent from a second hopper into the TSE at the same junction as the insecticide synergist and compatibilizer hopper. Absorbent agent addition was at a rate of 0.35 kg / hour, polymer was added at 3.15 kg / hour, compatibilizer at 2.1 kg / hour and insecticide synergist at 1 .4 kg / hour.

[0360] In each case, the pellets were stored at room temperature in heat sealed aluminium foil bags. Analysis was conducted on pellets at days 1 , 7, 14 and 28. All weight data was recorded to four decimal places.

[0361] References herein to “ppm” refers to “parts per million” by weight. Table 6

[0362] *1Versalis Greenflex HN 70 EVA with 28 % by weight vinyl acetate comonomer content (melt flow rate 6 g / min measured at 190°C in accordance with ISO 1133);

[0363] *2Biosynth PBO FP27076;

[0364] *3Sabie LLDPE M200024 (melt flow rate 20 g / min measured at 190°C in accordance with ISO 1133, 2.16 kg);

[0365] *4Versalis Greenflex ML 50 EVA with 19 % by weight vinyl acetate comonomer content;

[0366] *5Eraclene PC 82 HDPE (melt flow rate 20 g / min measured at 190°C in accordance with ISO 1133) 2.16 kg);

[0367] *6Key On Nano KNF-W silica aerogel, Average particle size about 20 |j.m; specific surface area 400 to 700 m2 / g;

[0368] *7DOW ELVALOY AC 1330, Ethylene methyl acrylate with 30 % by weight methyl acrylate comonomer content;

[0369] *8DOW ELVALOY AC 1218, Ethylene methyl acrylate with 18 % by weight methyl acrylate comonomer content;

[0370] *9DOW BYNEL 4157, Maleic anhydride modified LLDPE;

[0371] *10DOW NUCREL 925, Ethylene methacrylic acid;

[0372] Evaluation and Analysis Methods The polymeric materials as set out in Table 5 above (in the form of solid pellets) were stored at room temperature in heat sealed aluminium foil bags and analysed at days 1 , 7, 14 and 28.

[0373] The pellets were then washed and analysed as follows:

[0374] Pellets (0.5 g) were weighed into a vial, methanol (15 g) was added, and the vial was placed onto a roller mixer at 21 revolutions per minute (which took about 15 seconds to complete) for 3 minutes. The vial was removed from the roller, and the solvent was pipetted into a new vial (taking about 45 seconds to complete). The solvent was then diluted with methanol by a factor of either 900 (if the original pellets did not have visibly oily surfaces) or 10,000 (if the original pellets had visibly oily surfaces). The average amount (in ppm) of PBO on the pellet surfaces was then determined using the following Liquid Chromatography - High Resolution Mass Spectrometry (LC-HRMS) method.

[0375] LC-HRMS Method

[0376] Solutions of piperonyl butoxide (PBO) in methanol were prepared for analysis using Liquid Chromatography - High Resolution Mass Spectrometry (LC-HRMS) to quantify the concentration (parts per million, ppm) of PBO.

[0377] Liquid chromatography was carried out using a Thermo Scientific Vanquish Ultra-High Performance Liquid Chromatography (UHPLC) system using the following parameters:

[0378] Eluent gradient:

[0379] Time ( 5 100

[0380] 10 100

[0381] Mass spectrometry was carried out using a Thermo Scientific Q Exactive Focus with orbitrap mass analyser and heated electrospray ionisation (HESI) using the following parameters:

[0382] Calibration curves for quantification were generated using a commercial batch of PBO (obtained from Endura), dissolved in methanol to create a stock solution of known concentration (6000 ppm). The stock solution was diluted to create a seven-point calibration curve in the concentration range 0.001 ppm to 1 ppm. The calibration curve was linear across the working range with a coefficient of determination greater than 0.999. Samples were diluted in methanol as required to sit in the working range of the calibration curve. Peak areas of integrated peaks for the calibration solutions and samples were taken using the accurate mass of the PBO adduct [M+H]+, 361.1986.

[0383] An example of a seven-point calibration curve of PBO using the high-resolution mass spectroscopy detector with accurate mass search for peak detection is shown in Figure 1 .

[0384] Evaluation of effect of EVA on leakage of PBO form a polymeric material with varying doses of PBO

[0385] Polymeric material (in the form of solid pellets) C1 , C2, C3 and C4 according to Table 6 was analysed according to the method set out above. The results of the analysis are shown in Table 7. Table 7

[0386] Pellets indicated with * were not oily and underwent a x900 dilution in the method above. All other pellets were oily and underwent a x10,000 dilution.

[0387] A comparison of C1 and C2 with C3 and C4 respectively shows that the EVA copolymer reduces leakage of the PBO from the pellets at differing amounts of PBO.

[0388] Evaluation of effect of EVA on leakage of PBO form a polymeric material with varying vinyl acetate content

[0389] Polymeric material (in the form of solid pellets) C5 and C6 according to Table 6 was analysed according to the method set out above. The results of the analysis are shown in Table 8.

[0390] Table 8

[0391] Pellets shown in Table 8 were oily and underwent a x10,000 dilution.

[0392] Both C5 and C6 with differing amounts of acetate in the EVA copolymer reduced leakage of the PBO from the pellets.

[0393] Evaluation of effect of different polyolefins

[0394] Polymeric material (in the form of solid pellets) C4, C7 and C2 according to Table 6 was analysed according to the method set out above. The results of the analysis are shown in Table 9. Table 9

[0395] Pellets indicated with * were not oily and underwent a x900 dilution in the method above. All other pellets were oily and underwent a x10,000 dilution.

[0396] Table 9 shows that both the HDPE and LLDPE provide advantageous results, for example compared to C4 upon storage.

[0397] Evaluation of effect of addition of Silica

[0398] Polymeric material (in the form of solid pellets) C2, C8 and C9 according to Table 6 was analysed according to the method set out above. The results of the analysis are shown in Table 10.

[0399] Table 10

[0400] Pellets indicated with * were not oily and underwent a x900 dilution in the method above. All other pellets were oily and underwent a x10,000 dilution.

[0401] Table 10 shows that the silica aerogel can be used to tailor migration of the PBO to the surface of the pellets.

[0402] Evaluation of effect of varying the Compatibilizer

[0403] Polymeric material (in the form of solid pellets) C2, C4 (comparative), C10, C11 , C12 and C13 according to Table 6 was analysed according to the method set out above. The results of the analysis are shown in Table 11 . Table 11

[0404] Pellets indicated with * were not oily and underwent a x900 dilution in the method above. All other pellets were oily and underwent a x 10,000 dilution.3

[0405] Although a few preferred embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims.

[0406] As used in the specification and the appended claims, the singular forms "a", "an," and "the" include both singular and plural referents unless the context clearly dictates otherwise.

[0407] Throughout this specification, the term “comprising” or “comprises” means including the component(s) specified but not to the exclusion of the presence of other components. The term “consisting essentially of’ or “consists essentially of’ means including the components specified but excluding other components except for materials present as impurities, unavoidable materials present as a result of processes used to provide the components, and components added for a purpose other than achieving the technical effect of the invention. Typically, when referring to compositions, a composition consisting essentially of a set of components will comprise less than 5% by weight, typically less than 3% by weight, more typically less than 1% by weight of non-specified components.

[0408] Whenever appropriate, depending upon the context, the use of the term “comprises” or “comprising” may also be taken to encompass or include the meaning “consists essentially of’ or “consisting essentially of’, and may also be taken to include the meaning “consists of’ or “consisting of’.

[0409] As used herein, unless otherwise expressly specified, all numbers such as those expressing values, ranges, amounts of percentages may be read as if prefaced by the word “about”, even if the term does not expressly appear. For the avoidance of doubt, wherein amounts of components in a composition are described in wt%, this means the weight percentage of the specified component in relation to the whole composition referred to.

[0410] As used herein, the term "and / or," when used in a list of two or more items, means that any one of the listed items can be employed by itself or any combination of two or more of the listed items can be employed. For example, if a list is described as comprising group A, B, and / or C, the list can comprise A alone; B alone; C alone; A and B in combination; A and C in combination, B and C in combination; or A, B, and C in combination.

[0411] The optional features set out herein may be used either individually or in combination with each other where appropriate and particularly in the combinations as set out in the accompanying claims. The optional features for each aspect or exemplary embodiment of the invention as set out herein are also to be read as applicable to any other aspect or exemplary embodiments of the invention, where appropriate. In other words, the skilled person reading this specification should consider the optional features for each exemplary embodiment of the invention as interchangeable and combinable between different exemplary embodiments.

[0412] Each feature disclosed in this specification (including any accompanying claims, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

Claims

Claims1. An additive composition for addition to a polymeric material, the additive composition comprising an insecticide synergist, a compatibilizer and an absorbent agent.

2. An additive composition according to claim 1 , wherein the compatibilizer is a polymeric compatibilizer, such as a copolymer compatibilizer.

3. An additive composition according to claim 2, wherein the copolymer compatibilizer is a copolymer of ethylene and vinyl acetate, for example having a vinyl acetate content of from 2 to 40 wt% based on the total weight of the copolymer.

4. An additive composition according to any preceding claim, wherein the absorbent agent is selected from one or more of activated alumina, calcium oxide, a clay, a clay silicate, a zeolite and a silica.

5. An additive composition according to any preceding claim, wherein the insecticide synergist is selected from one or more of piperonyl butoxide (PBO) and n-octyl bicycloheptane dicarboximide.

6. An additive composition according to any preceding claim, further comprising a carrier, for example wherein the carrier comprises a polyolefin.

7. An additive composition according to any preceding claim, which is a solid composition, for example in the form of pellets.

8. A method of preparing an additive composition for addition to a polymeric material, the method comprising admixing the insecticide synergist with a compatibilizer and an absorbent agent.

9. A method according to claim 8, wherein the additive composition is an additive composition according to any of claims 1 to 7.

10. An insecticidal formulation comprising an insecticide synergist, a compatibilizer, an absorbent agent and an insecticide.

11. An insecticidal formulation according to claim 10, wherein the insecticide synergist, the compatibilizer and the absorbent agent are comprised in an additive composition according to any of claims 1 to 7.

12. A method of preparing an insecticidal formulation, the method comprising admixing an insecticide synergist, a compatibilizer, an absorbent agent and an insecticide.

13. A method according to claim 12, wherein the insecticide synergist, the compatibilizer and the absorbent agent are comprised in an additive composition according to any of claims 1 to 7 and wherein the method comprises the step of preparing the additive composition by admixing the insecticide synergist, the compatibilizer and the absorbent agent.

14. A method of preparing polymeric material having one or more of an insecticide synergist, a compatibilizer and an absorbent agent (preferably an insecticide synergist, a compatibilizer and an absorbent agent) incorporated therein, the method comprising:(i) selecting a polymeric material;(ii) contacting the polymeric material with one or more of the insecticide synergist, the compatibilizer and the absorbent agent (preferably with the insecticide synergist, the compatibilizer and the absorbent agent); and(iii) melt-processing the polymeric material.

15. A method of preparing polymeric material having one or more of an insecticide synergist, a compatibilizer and an absorbent agent (preferably an insecticide synergist, a compatibilizer and an absorbent agent) and an insecticide incorporated therein, the method comprising:(i) selecting a polymeric material;(ii) contacting the polymeric material with one or more of the insecticide synergist, the compatibilizer and the absorbent agent (preferably with the insecticide synergist, the compatibilizer and the absorbent agent) and with the insecticide; and(ii) melt-processing the polymeric material.

16. A method according to claim 14 wherein the polymeric material has an insecticide synergist, a compatibilizer and an absorbent agent incorporated therein or according to claim 17 wherein the polymeric material has an insecticide synergist, a compatibilizer, an absorbent agent and an insecticide incorporated therein.

17. A method according to claim 16, wherein the insecticide synergist, the compatibilizer and the absorbent agent are comprised in an additive composition according to any of claims 1 to 7.

17. A method according to any of claims 14 to 16, wherein the polymeric material comprises a polyolefin.

18. A method according to any of claims 14 to 17, wherein, in the method, the insecticide synergist, the compatibilizer, the absorbent agent, and optionally the insecticide, are contacted with the polymeric material when the polymeric material is in a molten state.

19. A method according to any of claims 14 to 18, further comprising the step of forming a fibre, wherein the fibre is formed downstream of the point of contact of the insecticide synergist, the compatibilizer, the absorbent agent, and optionally the insecticide, with the polymeric material.

20. A polymeric material, wherein the polymeric material incorporates one or more of an insecticide synergist, a compatibilizer and an absorbent agent.

21. A polymeric material according to claim 20, wherein the polymeric material further incorporates an insecticide.

22. A product comprising the polymeric material according to claim 20 or 21 .

23. A product according to claim 22, wherein the product is a fibre, especially a monofilament.

24. A product according to claim 22, wherein the product is a net, especially a LLIN, for example wherein the net is formed from one or more fibres, especially one or more monofilaments, according to claim 23.

25. A net according to claim 24, which is a mosquito repellent net.

26. A method of producing a fibre, the method comprising incorporating one or more of an insecticide synergist, a compatibilizer and an absorbent agent (preferably an insecticide synergist, a compatibilizer and an absorbent agent) into a polymeric material and forming the resultant polymeric material into a fibre.

27. Use of a polymeric material incorporating one or more of an insecticide synergist, a compatibilizer and an absorbent agent (preferably an insecticide synergist, a compatibilizer and an absorbent agent) to form a fibre.

28. A method of producing a net, especially a LLIN, the method comprising incorporating one or more of an insecticide synergist, a compatibilizer and an absorbent agent (preferably an insecticide synergist, a compatibilizer and an absorbent agent) into a polymeric material and forming the resultant polymeric material into a fibre, followed by forming one or more of the fibres into the net, especially the LLIN.

29. Use of a polymeric material incorporating one or more of an insecticide synergist, a compatibilizer and an absorbent agent (preferably an insecticide synergist, a compatibilizer and an absorbent agent) to form a net, especially a LLIN.

30. A method according to claim 26 or 28, further comprising incorporating an insecticide into the polymeric material.31 . A use according to claim 27 or 29, wherein the polymeric material further incorporates an insecticide.

32. A method of increasing the loading and / or the retention of an insecticide synergist in an additive composition comprising the insecticide synergist, the method comprising contacting the insecticide synergist with a compatibilizer and / or an absorbent agent in the additive composition.

33. A method of controlling the release of an insecticide synergist from an additive composition comprising the insecticide synergist, the method comprising contacting the insecticide synergist with a compatibilizer and / or an absorbent agent in the additive composition.

34. Use of a compatibilizer and / or an absorbent agent to increase the loading and / or the retention of an insecticide synergist in an additive composition comprising the insecticide synergist.

35. Use of a compatibilizer and / or an absorbent agent to control the release of an insecticide synergist from an additive composition comprising the insecticide synergist.

36. Use of an insecticidal formulation according to claim 10 or 11 , a polymeric material according to claim 21 , a product according to claim 22 or 23 or a net according to claim 24 or 25 to kill insects.

37. A method of killing insects, the method comprising contacting the insects with an insecticidal formulation according to claim 10 or 1 1 , a polymeric material according to claim 21 , a product according to claim 22 or 23 or a net according to claim 24 or 25 to kill insects.

38. An assembly comprising:(a) an extruder for extruding polymeric material;(b) a receptacle containing an additive composition according to any of claims 1 to 7 or an insecticide formulation according to claim 10 or 11 ; and(c) addition means operatively connected to the receptacle for adding the additive composition or the insecticide formulation from the receptacle into the polymeric material, for example in or downstream of the extruder.

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