DESCRIPTION

The present invention concerns the use of a composition with repellent activity against mosquitoes and other insects (bugs, ticks and mites), as a washing additive for giving anti-mosquito properties to a fabric through a washing process of said fabric.

In particular, the present invention refers to the use of a composition containing active principles with repellent activity ^" against mosquitoes and insect ^' s as ^" an additive of a domestic and industrial washing solution of a non-treated fabric or of a fabric already subjected to an anti-mosquito treatment for giving, recovering or improving the anti-mosquito properties of said fabric.

The present invention also regards a method for giving anti-mosquito properties to a non-treated fabric, for recovering the anti-mosquito properties of a degraded anti-mosquito fabric, for modifying the anti-mosquito properties of a degraded or non-degraded anti-mosquito fabric.

The anti-mosquito fabrics can be used in some niche fields, within ^' the clothing and furniture industries. The term anti-mosquito fabrics denotes a type of synthetic, artificial or natural fabrics containing mainly organic substances having a repellent effect against mosquitoes and insects in general. Such substances, in the following description, are called anti-mosquito compounds or anti-mosquito agents.

The anti-mosquito treatments on the fabrics are made in order to protect the user from insects and their annoying bites. Their action develops by contact (on the fabric) or by diffusion (in the immediate proximity to the fabric) .

At the industry level, the anti-mosquito fabrics can be produced by incorporation of anti-mosquito agents inside the starting yarn for preparing fabrics. In this case, the anti-mosquito agents are added during the spinning step of the fibres (mainly synthetic or artificial ) .

As an alternative to this technique, more frequently, anti-mosquito fabrics .can be prepared by appropriately treating with anti-mosquito agents the fibre or fabric in its final form (chemical finishing treatments) . In this case, in order to bind the anti- mosquito agents to the fibres of the fabric, compositions containing molecules that adhere to the fabric and, simultaneously, support the anti- mosquito agents can be used.

There exist different types of anti-mosquito agents used in the textile industry for preparing anti- mosquito fabrics. Examples of such anti-mosquito agents are: DEET (N, -diethyl-3-methylbenzamide or diethyltoluamide) , picaridin or icaridin (hydroxyethylisobutyl piperidine carboxilate) , permethrins, pyrethroids, natural oils (such as lemongrass or geranium extract) , and/or mixtures thereof.

A first drawback associated with the use of the anti-mosquito fabrics known in the prior art, especially the anti-mosquito fabrics obtained with chemical finishing, is the progressive degradation of their anti-mosquito effectiveness. In particular, because of the mechanical, chemical and thermal action due to the succession of washing treatments, the anti- mosquito fabrics become less and less effective in neutralising the presence of mosquitoes and annoying insects, until they definitely lose their action after a limited number of washing cycles.

In the case of anti-mosquito fabrics produced with yarns being made anti-mosquito ^' during the fibres preparation step, the phenomenon of progressive loss of the anti-mosquito effectiveness is less acute because the active principle is included within the fibre and is virtually available until the fibre is completely degraded. On the other hand, precisely because the active principle is inserted within the fibre, it is not possible to release the right amount of active principle capable of neutralising the presence of mosquitoes and annoying insects. This on average results in an poor or limited effectiveness or in the need to have very high amounts of active fibres, with possible consequences related to the toxicological and eco-toxicological effects of the anti-mosquito principle and with a strong cost increase of the anti- mosquito textile.

In the attempt to overcome the above drawbacks of the anti-mosquito fabrics, the field research aimed to improve the durability and effectiveness of the anti- mosquito agents attached to the fabrics. To this purpose, chemical compositions and processes have been developed for treating fibres and fabrics capable of more firmly anchoring anti-mosquito agents, such as, for example, the so-called "grafting" (in Italian, "ancoraggio" ) processes of the fibres with polymeric resins and the micro-encapsulation processes of anti- mosquito agents into the fibres. The anti-mosquito fabrics thus created are characterised by a longer durability, due to slower degradation of the properties, and therefore they allow a less frequent replacement .

The above compositions and processes for producing fibres and yarns and those for finishing the textiles, however, are economically unattractive and have the additional drawback of adversely affecting the release dynamics of the anti-mosquito agents by the fabric and, therefore, on their effectiveness in neutralising insects .

In the prior art there are also known chemical compositions and processes for preparing regenerative anti-mosquito fabrics, i.e. anti-mosquito fabrics whose properties can be restored by a suitable chemical treatment .

An important class of compounds with which regenerative anti-mosquito fabrics can be made is represented by cyclodextrins , cellulose molecules with a basket structure. Cyclodextrins, however, are only "receptacles" to be anchored to -the fibres and to be filled with active principles having different functions (anti-mosquito, antimicrobial, scented substances). Therefore, to ensure effectiveness continuity thereof, it would be necessary to proceed to a selective and recurring filling with the desired substance, under specific chemical-physical conditions (pH, temperature, concentration of reactive species) and with reaction catalysts. In other words, the user would be forced to bring back the garments to the supplier in order to carry out the aforesaid specific filling. Moreover, a further drawback of cyclodextrins is the difficulty to adjust the release dynamics of the substance put into the baskets. The release, in fact, would occur following the variation of some chemical- physical parameters during the use of the anti-mosquito garment (pH, temperature, salt concentration) , which would modify the three-dimensional conformation of cyclodextrins, this resulting in the release of the included substance. This suggests that a modulation of the release process is not possible, or it ^' is only possible by roughly intervening in advance on the structure of cyclodextrins (e.g. on the size of the basket: α, β, γ-cyclodextrins ) .

It is the object of the present invention to overcome the disadvantages highlighted by the prior art.

A first object of the present invention is the use of a composition with repellent action against mosquitoes and insects in general, as an additive in a washing solution for giving anti-mosquito properties to a non-treated fabric, through a washing process of said fabric .

A second object of the present invention is the use of an anti-mosquito composition as an additive of a washing solution for recovering the anti-mosquito properties of a degraded anti-mosquito fabric, through a washing process of said fabric.

A further object of the present invention is the use of an anti-mosquito composition as an additive of a washing solution for modifying the anti-mosquito properties of a degraded or non-degraded anti-mosquito fabric, through a washing process of said fabric.

Finally, an object of the present invention is to provide a method for giving anti-mosquito properties to a non-treated fabric, for recovering the anti-mosquito properties of a degraded anti-mosquito fabric, for modifying the anti-mosquito properties of a degraded or non-degraded anti-mosquito fabric.

For the purposes of the present invention the term

"anti-mosquito" means the property of a compound, chemical composition, fibre, yarn or fabric to exert a repellent action against mosquitoes and insects in general (bugs, ticks, mites).

For the purposes of the present invention the term

"degraded anti-mosquito fabric" means an anti-mosquito fabric that has lost the original anti-mosquito effectiveness given through an appropriate treatment.

For the purposes of the present invention the term "non-treated fabric" means a fabric to which anti- mosquito properties have never been given through an appropriate treatment.

The Applicant has surprisingly found that it is possible to give anti-mosquito properties to non- treated fabrics during a domestic or industrial washing process of a fabric, by using an anti-mosquito composition such as those given above as an additive in a washing solution. Similarly, the same compositions can be used in a domestic or industrial washing process of degraded anti-mosquito fabrics to recover the original anti-mosquito properties thereof or to change the anti-mosquito properties of a degraded or non- degraded fabric.

The anti-mosquito compositions that can be used for the purposes of the present invention are the compositions known in the prior art for textile applications. They are produced by companies specialised in textile chemical additives and they are commercially available, usually in the form of aqueous solutions of different concentrations.

For the purposes of the present invention any anti-mosquito composition can be used that, once added to a washing solution, is capable of fixing by contact one or more, anti-mosquito compounds (hereinafter also called anti-mosquito agents) to the fibres of a fabric subjected to washing with said solution.

Examples of anti-mosquito compositions are the compositions comprising one ore more compounds selected from the group consisting of: DEET (N, N-diethyl-3- methylbenzamide or diethyltoluamide ) , picaridin or icaridin (hydroxyethylisobutyl piperidine carboxilate) , permethrins, pyrethroids, natural oils (such as lemongrass or geranium extract), and/or mixtures thereof .

In a preferred embodiment of the present invention, the Applicant has developed an anti-mosquito composition comprising a permethrin-based (a mixture of cis and trans isomers) solution, applicable to the textile fabric in the manner ^' and within a timeframe consistent with a normal domestic or industrial washing. This solution is particularly suitable for giving anti-mosquito properties to fabrics intended to come into contact with the human body, such as garments (for instance shirts, trousers, jackets, polo-shirts, sweatshirts, t-shirts, socks), fabrics for mattresses, bed linen (for instance mattress-covers, sheets, pillowcases, pillows), sleeping bags, curtains, sports or hiking clothing (for hunting, trekking, fishing, forest rangers), and so on.

In a further preferred embodiment of the present invention, the anti-mosquito composition comprises DEET (N, N-diethyl-3-methylbenzamide or diethyltoluamide ) - based compounds.

The present invention can be applied to different types of fabrics, comprising natural, synthetic or artificial fibres, fabrics having two or more layers either with a spread-coating (spread-coated) or with a membrane (laminated).

The use of anti-mosquito compositions according to the present invention is particularly effective on fabrics comprising textile fibres, pure or in blends, selected from the group consisting of polyester fibres, cellulose fibres (natural or artificial), polyamide fibres and acrylic fibres. Moreover, it is also applicable to special fibres such as modacrylic fibres, polypropylene fibres and aramidic fibres, even in the presence of PU (polyurethane ) -based coatings or PTFE (polytetrafluoroethylene) -based membranes .

The domestic or industrial washing processes in which the present invention can be applied are the washing processes performed in common domestic washing machines or in continuous or discontinuous washing machines known in the prior art. Said processes involve several steps such as soaking, pre-washing, washing, bleaching, rinsing, neutralising, _^ centrifuging and drying . The steps of the washing process and their orderof succession may vary depending on the type of fabrics subjected to washing, with particular reference to the colour, the chemical composition of the fabric, the type of dirt and the intended use.

The anti-mosquito compositions are added to the washing solutions in the form of aqueous solutions. The anti-mosquito composition is preferably added to the washing solution used for finally rinsing the garments subjected to washing, therefore, preferably, when adding the softener.

Advantageously, the fabric is subjected to a pretreatment for preparing the fibre, through soaking or pre-washing with preparation or "grafting" solutions.

Advantageously, and more generally, the fabric is subjected to a "grafting" process through specific linkers (preferably acrylates and/or urethanes) mixed with the anti-mosquito principle, whereby said linkers joining to the anti-mosquito principle increase the substantivity thereof on the textile fabric and allow a finishing for exhaustion in the final washing conditions .

This pretreatment is normally carried out directly in a single step, by using a mixture of the active principle and one or more molecules that bind to it and improve its affinity for the textile backing, allowing a more homogeneous finishing of the textile surface.

In particular, the Applicant has experienced an increase in substantivity, i.e. specific affinity of the molecule to the fibre, between the active principle and textile backings having different chemical natures (in particular polyester- and cotton-based) , by using a linker molecule, specifically an acrylates-based molecule, in equimolar amount with respect to the active principle.

Such linker molecules optimise the pretreatment of the textile backing and make it possible in a normal washing in a washing machine that provides short contact times and low concentrations of the bath.

Thus, surprisingly, the Applicant has found that to obtain an effective finishing in terms of amount of active principle per surface of the treated textile support and in terms of homogeneity of the distribution of the active principle, it is necessary to use a mixture of active principle and linker.

The dosage of the anti-mosquito composition in the washing solution varies with the type of fabric subjected to washing. Generally, the dosage of the anti-mosquito composition is such as to make available in the washing solution a total amount of anti-mosquito compounds ranging from 1 to 5 g per kg of dry fabric subjected to washing, preferably from 2 to 4 g.

The best results in the use of the anti-mosquito compositions according to the present invention are achieved by maintaining the pH of the washing solution containing the anti-mosquito agents at a slightly acidic value (less than or equal to 6.5) . The pH of the solution can vary depending on the specific nature of the anti-mosquito composition used and of the composition of the preparation to which it is added (softener, detergent, additive ...) .

During the washing of the fabric the anti-mosquito agents present in the washing solution come into contact with the fibres of the fabric and adhere to their surface, thanks to specific linkers (for instance, hydroxyls, nitrogen heterocycles , amino derivatives). The amount of anti-mosquito agents adhering to the fabric at the end of washing strictly depends on the type of fibre, on the concentration of said agents in the washing solution and on the contact time .

In general, with fabrics made of irregular and hydrophilic fibres, such as natural fibres, more effective finishings are obtained because a greater amount of active principle can be bound to the fibre compared with fabrics made of monolithic and hydrophobic synthetic fibres.

During treatment the fabrics are usually kept in agitation in the washing solution, which contains the anti-mosquito composition, and this promotes uniform contact of the fabric mass with the anti-mosquito agents. With the above-mentioned concentrations of anti-mosquito agents, the contact time between the anti-mosquito agent and the textile material must be at least 3 minutes. The homogeneity of the treatment is directly proportional to the contact time between the anti-mosquito agent and the textile material.

In a preferred embodiment of the present invention, the fabrics subjected to washing are non- treated fabrics, regenerated and non-regenerated anti- mosquito fabrics of garments (such as, for instance, shirts, trousers, jackets, polo-shirts, sweatshirts, t- shirts, socks), fabrics for mattresses, bed linen (for instance mattress-covers, sheets, pillowcases, pillows) , sleeping bags, curtains, sports or hiking clothing (for hunting, trekking, fishing, forest rangers), and so on.

The use of anti-mosquito compositions according to the present invention offers several advantages over the uses known in the prior art. The use of anti- mosquito compositions in a domestic or industrial washing process according to the present invention allows to give in a simple and inexpensive way anti- mosquito properties to non-treated fabrics, avoiding the costly conventional finishing processes. Moreover, it guarantees the anti-mosquito effectiveness for a long time, because the treatment is regenerated upon each washing.

Similarly, with the present invention it is possible to recover the anti-mosquito properties of degraded anti-mosquito fabrics or to modify the properties of anti-mosquito fabrics according to the needs of the user. For example, it is thus possible to extend the effectiveness of a still unused anti- mosquito fabric, by subjecting it to a simple washing process performable by anyone in his/her own domestic washing machine and without further use indications. In this regard it is advisable to add the anti-mosquito principle to the washing products, preferably to the softener, so that, with the addition of the usual laundry product, the advantage of giving a new property to all the treated textile material can be achieved.

A further advantage of the present invention is related to the possibility of allowing to easily modulate the anti-mosquito effectiveness of the treated fabrics, by acting on process parameters such as the concentration of the anti-mosquito composition used as an additive of the washing solution, the pH of the solution and the contact time.

The anti-mosquito compositions usable for the purposes of the present invention have toxicological and eco-toxicological characteristics consistent with the reference international standards of the field, particularly with regard to biodegradability and biocompatibility (OECD 406, ISO 10993-5, Oeko Tex Standard 100) .

The anti-mosquito compositions according to the present invention can be used in a method for giving anti-mosquito properties to a non-treated fabric, for recovering the anti-mosquito properties of a degraded anti-mosquito fabric, for modifying the anti-mosquito properties of a degraded or non-degraded anti-mosquito fabric, this method essentially comprising the steps of preparing an anti-mosquito composition comprising a mixture of anti-mosquito active principle and linkers, and using said anti-mosquito composition as an additive of a washing solution in a domestic or industrial washing process of said fabric.

Said method further comprises the step of subjecting the fabric to a "grafting" process through said linkers mixed with the anti-mosquito principle.

The following implementation examples are given by way of sole illustrative purpose of the present invention and they should not be construed by limiting the scope defined by the attached claims.

In particular, the following examples represent the experiments carried out by the Applicant in order to demonstrate the amazing results achieved with the invention according to the present invention. Still more particularly, in the following example 1 a procedure of simple addition of the -active principle in the final washing step is accomplished, which leads to an unsatisfactory result, since the distribution on the textile material is not uniform and areas having a too low concentration (lack of effectiveness) and other areas having a too high concentration (risk of adverse effects on the user) are created .

On the contrary, in example 2, however, a procedure is accomplished that differs from the previous one in that it provides the addition of "linkers" in order to ensure the maximum finishing effectiveness on the textile material; all the experimental data that follow in example 2 refer to this procedure, then providing for the use of linkers.

The use of the linkers, or binders, is known in the textile field, especially in foulard baths applications (immersion of the textile materials in tanks where finishing takes place for exhaustion of the principle on the fibre) .

These molecules are capable of binding to textile fibres of various types through electrostatic interaction and of creating an activated surface layer, more similar to the functionalising molecule.

The best and most reproducible results according to the present invention have been obtained by using an acrylic dispersion, in an amount of the order of 3% v / v mixed with permethrin; specifically, the commercial product Clariant Appretan N92111 was used.

EXAMPLE 1

5 kg of non-treated fabric consisting of leisure clothing were subjected to a washing process in a washing machine. The fabric was made of a blend of polyester, cotton and acrylic fibres. The washing process consisted of the following steps: soaking, pre- washing, washing at 60 °C, bleaching, neutralising, rinsing with a washing solution added with an anti- mosquito composition, centrifuging and drying.

During the rinsing step an anti-mosquito composition based on permethrin having cis and trans isomeric forms with a 25:75 ratio was added in an amount equal to 1 g of commercial product (approximately 0.8 g of anti-mosquito agents) for each kg of dry fabric subjected to washing.

The fabric was rinsed with this solution for at least 3 minutes. The fabric was then centrifuged and dried .

The fabric was subjected .to extraction and subsequent analysis of the extract by HPLC chromatography, which revealed the presence of the anti-mosquito principle on the textile material, but with a not perfectly homogeneous distribution of the anti-mosquito effectiveness. In particular, according to the "Technical Supply Specifications TL 8305-0331 (BWB, for NATO army use)", a textile material is considered to have anti-mosquito properties if the chromatographic analysis after extraction shows a residue of the active principle in the textile material not lower than 200 mg / square meters.

EXAMPLE 2

In comparison with the previous example, a

^■ solution containing the "linkers" (linking molecules between the active principle and the textile material) was used, so as to ensure maximum effectiveness of the textile finishing.

5 kg of non-treated fabric consisting of leisure clothing were subjected to a washing process in a washing machine. The fabric was made of a blend of -polyester, cotton and acrylic fibres. The washing process consisted of the following steps: soaking, pre- washing, washing at ≥ 60 °C, bleaching, neutralising, rinsing with a washing solution added with an anti- mosquito composition, centrifuging and drying.

During the rinsing step, after the rinsing bath was neutralised to a pH value between 5.5 and 6.5, an anti-mosquito composition based on permethrin having cis and trans isomeric forms with a 25:75 ratio was added in an amount equal to 1 g of commercial product (approximately 0.8 g of anti-mosquito agents) for each kg of dry fabric subjected to washing.

The fabric was rinsed with this solution for at least 3 minutes. The fabric was then centrifuged and dried.

The fabric was subjected to extraction and subsequent analysis of the extract by HPLC chromatography, which revealed the presence of the anti-mosquito principle on the textile material in an amount sufficient to give anti-mosquito properties. In particular, according to the "Technical Supply Specifications TL 8305-0331 (B B, for NATO army use)", a textile material is considered to have anti-mosquito properties if the chromatographic analysis after extraction shows a residue of the active principle in the textile material not lower than 200 mg / square meters. The following are the results of tests to assess effect of finishing depending on the concentration active principle in the washing bath.

Table 1. Results HPLC of analysis after extraction.

As it can be seen from the above results, the bath concentration to obtain a satisfactory finishing is equal to 1 g of active principle per kg of dry textile material subjected to washing. On this reference concentration, the anti-mosquito properties of the fabric have then been tested by means of specific tests performed in specialised European laboratories (STI- Swiss Tropical Institute in Basel (CH) and Biogents of Regensburg for tests on mosquitoes and the Zoological Institute of Neuchatel (CH) for the effectiveness on mites and bugs), where the anti-mosquito effectiveness was determined by comparison with reference to non- treated textile materials. The comparative tests have been carried out by examining the number of insects landing on the fabric (according to STI Norm MV-02 "Reduction of insect landings") and the number of bites that are caused, by comparing the behaviour of the anti-mosquito textile to that of a non-treated reference textile material.

The samples with a residue of the active principle in the textile material not less than 200 mg / sq. m, showed a very good effect (reduction greater than 85% compared with the non-treated reference sample), thus proving to be effective in the repellent action against mosquitoes and insects.