WO2020016111A1

WO2020016111A1 - Multi-functionalised multilayer plastic films for a tool for controlling arthropods harmful to plants, animals or humans

Info

Publication number: WO2020016111A1
Application number: PCT/EP2019/068762
Authority: WO
Inventors: Pierre Francis GUILLET; Marc Guy Jean-Jacques DESQUESNES
Original assignee: Centre De Cooperation Internationale En Recherche Agronomique Pour Le Developpement (Cirad); A To Z Textile Mills Limited
Priority date: 2018-07-18
Filing date: 2019-07-11
Publication date: 2020-01-23
Also published as: FR3083965A1; FR3083965B1

Abstract

Disclosed is a film for tools for controlling arthropods harmful to plants, animals or humans, allowing the reflection and/or transmission of light originating from a natural and/or artificial source, said film comprising at least one pigment such that the light reflected and/or transmitted by said film has a specific wavelength peak suitable for specifically attracting or repelling the targeted arthropods, and at least one active agent for killing and/or sterilising or repelling the targeted arthropods when they come into contact with the film, characterised in that said film comprises a plurality of juxtaposed layers, including a first layer of polymer material capable of allowing the migration of said active agent, one of the components out of the pigment and the active agent being incorporated into said first layer of polymer material, the other component being either deposited on the surface of said first layer of polymer material so as to form a second layer, or incorporated into a second polymer layer capable of allowing the migration of said active agent.

Description

Multifunctional multilayer plastic films for arthropod control tool harmful to plants, animals or humans

The present invention relates to the field of films, screens, ribbons and other supports for the attraction and control, or repulsion, of target arthropods, in particular insects harmful to plants, animals or man.

In plants, harmful insects are most often phytophagous arthropods, which feed on the contents of cells or the sap of plants; in animals and humans, these may in particular be compulsory or optional blood-sucking diptera. These arthropods, which are parasites of agricultural, veterinary or human health interest, are sometimes repelled, but most often attracted by certain specific colors such as yellow, ultra-violet or blue. These attraction and repulsion generally result from the light which is reflected and / or transmitted by a colored substrate. Depending on the dyes used, certain wavelengths of the light spectrum are reflected or transmitted more intensely than the others.

If we take the example of blood-sucking insects, there are control tools in the form of colored traps or colored screens mounted on a support. Such screens include a fabric film, dyed blue and treated with an insecticide, and a fixing device; they are used to fight tsetse flies in Africa. The flies attracted from a distance by the fabric films, come to land on their surface and then come into contact with the insecticide. To be effective, these blue dyed fabrics must reflect light with a very specific wavelength (in this case, as close as possible to 450-460 nanometers). Different wavelengths, even relatively close to the target wavelength, do not attract tsetse flies, and may even repel them. Thus, to be effective, the fabrics must be dyed with a very specific blue color. Any variation in color or blue tint, by changing the spectrum of the reflected light can significantly reduce the effectiveness of traps or screens constructed from these fabrics. In addition, such a variation in color may have the consequence that certain non-target insects, such as pollinating insects, are in turn attracted to the film. An uncontrolled change in the population of pollinating insects can have dramatic consequences.

In the case of tsetse flies, so far only colored fabric films have been used. With these films made of dyed fabrics, it is extremely difficult to obtain precisely the same color from one batch to another. These variations are not acceptable insofar as a colorimetric variation, even a very small one, will have a direct influence on the wavelength of the reflected or transmitted light and therefore on the capacity of the film to attract the targeted insects.

The fabric films having the best attractiveness for the target insects are made of cotton blend, therefore their cost is high. Films made of synthetic fabrics (polyester for example) have a lower price, but their attractiveness is also less. Certain constituent elements of films therefore have effects on their attractiveness. In particular, the reflectance and transmittance of the materials used are important parameters. The more intense the reflected light, the more attracted the target insects. The reflectance of a film for a given color (wavelength) deemed to be attractive must therefore be as high as possible. Likewise, the more intense the specific light transmitted, the more the target insects are attracted. The transmittance of a film used outdoors must therefore also be maximum. It has been observed by the Applicant that the intertwined fibers of cotton or synthetic fabrics, by the nature of the fibers and the texture of the fabric, have less reflectance than homogeneous surfaces. Likewise, their transmittance is limited, part of the light being captured in the tissue or unable to pass through its structure. It is therefore understood that the nature of the material forming the film plays an important role in its effectiveness. In addition, whatever the material used, the fabric absorbs a large amount of insecticide solution, around 80 to 100% of its weight. For the screen to be effective, the concentration of insecticide on the surface of the film must be high enough. However, most of the insecticide soaked in tissue is located and retained inside the tissue. This part of the insecticide is therefore not bio available on the surface to kill arthropods which arise on the tissue. There is therefore an important difference between the quantity of biologically active material used for the impregnation of a tissue (large) and the quantity which is actually available on the surface of the latter (small).

In addition, under the effect of climatic conditions, the amount of insecticide available in a fabric will vary greatly over time, the insecticide being deteriorated by the exposure of the film to the sun. Indeed, the sun can alter the chemical properties of any biologically active material found in the fabric film used outdoors. Protectors should therefore be added, which is an additional step that is both technically delicate and costly to impregnate the fabric.

Also, the rain drains the insecticide out of the impregnated fabric. Said insecticide then diffuses into the soil, which represents a loss in terms of effectiveness and generates significant environmental contamination.

An objective of the invention is to solve at least one of the aforementioned drawbacks.

In particular, there is a need for a film for the control of certain harmful arthropods of plants, animals and humans having a targeted attractiveness and an improved reflectance or transmittance, a high bioavailability at the surface of products toxic for insects and, if possible, increased resistance to climatic conditions.

Thus, the subject of the present invention is a film for tools for controlling arthropods harmful to plants, animals or man, making it possible to reflect and / or transmit light coming from a natural source and / or artificial, said film comprising at least one pigment so that the light reflected and / or transmitted by said film has a specific wavelength peak capable of specifically attracting or repelling targeted arthropods and at least one active agent allowing to kill and / or sterilize or repel the target arthropods when they come into contact with the film, characterized in that said film comprises a plurality of juxtaposed layers including a first layer of polymeric material capable of allowing the migration of said active agent, one of the components among the pigment and the active agent being incorporated into said first layer of polymer material, the other component being either deposited on the surface of said first layer of polymer material so as to form a second layer, or incorporated in a second layer of polymer capable of allowing the migration of said active agent.

The effect of such a film, by virtue of its polymer composition, is to control the reflectance and transmittance of light more precisely. Thus, the wavelength peak of the light reflected and / or transmitted by said film is narrower and makes it possible to attract or repel more effectively and more selectively the targeted arthropods.

In addition, the intensity of the reflectance of the film and its resistance to climatic conditions are also improved. The improvement in the intensity of the reflectance makes it possible to attract a larger number of targeted insects and the improvement in the resistance to climatic conditions makes it possible to increase the lifespan of the film.

In addition, the multilayer appearance of the film makes it possible to functionalize each of the layers of the film separately and therefore to more precisely control its reflective, through, bioactive and / or protective properties.

The film according to the present invention may also include one or more of the following characteristics, considered individually or in any technically possible combination:

the active agent is incorporated into the first layer of polymer, the polymer material capable of allowing the migration of an active agent is selected from polyethylene terephthalate (PET), polyethylene (PE) or polypropylene (PP),

the film comprises a reflective material such as a white pigment, metallic particles or any other suitable reflective material,

- only one component among the pigments, active agents and reflective materials is incorporated into a given polymer layer,

- the pigment is incorporated into the outermost polymer layers of the film,

the film has a thickness of between 30 μm and 300 μm,

the film comprises a third layer between the first and the second layer, said third layer comprising a polymeric material limiting the migration of the active agent,

the polymer material limiting the migration of the active agent comprises polyamide (PA),

the polymer layer comprising the active agent also comprises an adjuvant making it possible to modulate the speed of migration of the active agent in the film,

- the adjuvant comprises silica,

at least one of its layers of polymer material comprises a protective agent,

- the protective agent comprises a UV stabilizer,

one and / or the other of the film surfaces comprises a first central zone defined by the presence of a first pigment and a second peripheral zone containing a second pigment,

the nature and the quantity of the pigment (s) used are selected so that the reflected and / or transmitted light has a wavelength peak between 450 nm and 460 nm,

- The nature and the quantity of the pigment (s) used are selected so that the reflected and / or transmitted light has a wavelength peak between 330 nm and 390 nm. The invention also relates to a screen for controlling arthropods harmful to plants, animals and humans, comprising at least one film as described above as well as a system for attaching said film.

The invention will be better understood and other details, characteristics and advantages of the invention will appear on reading the following description given by way of non-limiting example and with reference to the appended illustrations in which:

- Figure 1 shows the reflectance spectra of a plastic film according to an embodiment of the invention and two fabric films according to the state of the art;

FIG. 2a shows the reflectance of the plastic films according to 2 embodiments of the invention and of two fabric films according to the state of the art,

FIG. 2b shows the transmittance of the plastic films according to 2 embodiments of the invention and of two fabric films according to the state of the art,

FIG. 3 represents a film according to a first embodiment of the invention,

- Figure 4 shows a film according to a second embodiment of the invention

FIG. 5 represents a screen according to an embodiment of the invention,

- Figure 6 is a photograph of a screen according to an embodiment of the invention.

In the sense of the present invention, the term "film" refers to a thin layer or a plurality of thin layers of material. Depending on the nature of this material, we will speak of "fabric film" to designate a fabric coupon made of intertwined threads, or of "plastic film" to designate a homogeneous and continuous plastic sheet.

Within the meaning of the present invention, the term “layer” refers to a layer of material having a homogeneous and continuous surface. Said layer being present alone or on the surface of another layer of material. Thus, if a material is deposited on the surface of a layer of polymer, then the deposition of material is considered to form a new layer, and the assembly which results therefrom will be qualified as a multilayer material. Within the meaning of the present invention, the term “covering film” designates a large area film, of non-predetermined shape and intended to cover surfaces of windows or greenhouses, residential or agricultural; the term “screen” designates a film of size close to or less than 1 m ² and of generally square or rectangular shape; the term “ribbon” designates a narrow film (a few centimeters) and long (a few meters); covering films, screens and ribbons are therefore 3 distinct forms of supports designed from films and commonly used in arthropod control.

The films of polymeric materials according to the invention are in particular obtained by extrusion and / or by rolling. Such techniques make it possible to obtain films having a homogeneous and continuous surface, without these characteristics being systematically required in all the layers.

A film 1 according to the present invention has two sides. Each of these faces represents the surface of the film. The surface of the film constitutes the area on which the target insects attracted by the film come to rest.

When light from a natural or artificial source reaches a material, part of this light is absorbed, part is transmitted and part is reflected. The transmitted light corresponds to the part of the light which crosses the material. The reflected light corresponds to the part of the light which is neither absorbed nor transmitted. The reflectance and transmittance of a material depend on the spectral composition of the light and the material forming the film.

The film 1 according to the invention comprises at least one pigment so that the light reflected and / or transmitted by said film 1 has a specific wavelength peak capable of attracting or specifically repelling the targeted arthropods and an agent active to kill and / or sterilize or repel target arthropods when they come into contact with the film 1.

The film 1 according to the invention comprises at least a first layer of polymer material allowing the migration of the active agent. The polymers used may for example be polyethylene terephthalate (PET) or polyolefins such as polypropylene (PP) or polyethylene (PE).

The film 1 according to the present invention comprises at least one pigment. Said pigment is either incorporated into a first layer of polymer capable of allowing the migration of said active agent, or deposited on the surface of said first layer of polymer material so as to form a second layer, or incorporated into a second layer of polymer capable of allow the migration of said active agent. The presence of pigment in the plastic film makes it possible to control the color of the film and therefore the wavelength of the lights reflected or transmitted by the film.

The use of a polymer allowing the migration of an active agent in the film allows better control of the distribution of said at least one pigment in the film compared to fabric films.

When said at least one pigment is poorly distributed in or on the surface of the film, there may be passage of light rays which do not come into contact with the pigment. This results in poor control of the reflectance and transmittance spectrum and results in a narrower peak around the target wavelength. This phenomenon is observed with fabrics which in particular allow rays of white light to pass through the interstices between the meshes of the fabric.

Thus, by using a homogeneous and continuous medium (unlike the interlacing of the fibers of a tissue) and by improving the control of the distribution of the pigments, it is possible to obtain a wavelength peak of the narrower reflected and / or transmitted light, and better control of the reflectance and transmittance spectra. A narrower peak is more specific to a type of insect targeted by the film and therefore makes it possible to more specifically attract said targeted insects.

The polymer material or materials used in the film 1 according to the invention also make it possible to improve the reflectance. Reflectance is the proportion of light reflected from the surface of a material. A higher reflectance results in a greater intensity of reflected light and thus attracts a larger quantity of target insects.

In addition, in particular when the pigments are incorporated into a layer of polymeric material, said pigments are less subject to degradation due to weather. For example, a pigment incorporated in a layer of polymeric material of a film 1 according to the invention will be less altered by rain than in a fabric film, there will therefore be little or no variation in color over time . By decreasing the variation in the quantity of pigment present in the film, the presence of polymer makes it possible to maintain a spectrum of transmittance and reflectance stable over time and therefore to maintain a narrow peak at the target wavelength. Thus, the film 1 according to the invention has an improved lifespan.

The type of pigment and the amount of pigment used are determined according to the arthropods targeted.

Advantageously, the film 1 according to the invention comprises a plurality of identical or different polymer layers.

The presence of a plurality of layers of polymers makes it possible to generate and associate individual characteristics of the different layers (of identical or different polymer composition or of variable thicknesses as required), in order to better manage the overall characteristics of the product, by associating to each of the layers various elements necessary for the desired functionality. Thus, the addition of several layers of polymer makes it possible to manage the functionality of each layer well, but also to combine, through the various layers: optical properties (for example: external layers of UV protectors; intermediate layers selecting a length of given wave; reflective central layer, etc.), chemical properties (for example: external layer with contact bioactive agents: arthropod sterilizing agents, growth inhibitors, insecticides, acaricides, potentiators; intermediate layer with potentiators or olfactory attractants, etc), or else to have on the surface of the film an attractive coloring ink, even toxic for arthropods.

A film 1 according to the invention having several layers of polymer makes it possible to dissociate poorly compatible compounds by placing them in different layers, or even separating them by an intermediate layer. The film 1 having a plurality of polymer layers also has excellent mechanical strength and low production cost. We can even design a film whose one side would be visually or chemically attractive to target arthropods, and the other side repellent.

As mentioned above, the film 1 according to the invention comprises at least one active agent making it possible to kill and / or sterilize or repel the target arthropods when these come into contact with the film. Said active agent is either incorporated into a first layer of polymer capable of allowing the migration of said active agent, or deposited on the surface of said first layer of polymer material so as to form a second layer, or incorporated into a second layer of suitable polymer to allow the migration of said active agent.

Such active agents can for example make it possible to sterilize and / or intoxicate the target arthropods when they come into contact with the film. The active agents used can be mechanical active agents and / or biological active agents.

Advantageously, the active agent is a biological active agent such as for example an insecticide, a pheromone, a growth inhibitor, an olfactory attractant and / or a potentiator.

In particular, the biological active agent can be a synthetic insecticide or acaricide (fast-acting, slow-acting or developmental inhibitor) or a substance having insecticide or acaricide properties of natural origin such as toxins, spores or any toxic entity from animal, fungal, bacterial or botanical organisms used to attract, kill or sterilize target insects.

The role of the insecticide or miticide is to kill or sterilize the target arthropods when the latter are in contact with the film according to the invention. Pheromones and olfactory attractants help attract target arthropods.

Depending on the desired effect, these active agents can be deposited on the surface of the film or be incorporated into the layer of polymeric material. When an active agent is deposited on the surface of the film 1, said active agent constitutes a new layer of the film insofar as the deposition is homogeneous and continuous. When an active agent is incorporated into a layer of polymeric material allowing the migration of an active agent, said active agent will migrate through the polymer to the surface of the film. This migration makes it possible to increase the life of the film and to control the amount of active agent on the surface.

The different active agents, mechanical and biological, can be combined with each other to improve the effectiveness of the attraction film.

The film 1 can also include a protective agent intended to protect the active agent (s) present in or on the surface of the film 1. An example of a protective agent which can be used is a UV stabilizer. Said UV stabilizer makes it possible to protect from the sun an active biological agent and / or the polymer or polymers entering into the composition of the film 1. Indeed, under the effect of the sun, an active biological agent such as an insecticide can see its properties chemicals progressively altered by UV rays and possibly produce one or more metabolites accelerating the degradation of the polymer (s).

Protective agents can also be used to protect the polymer and / or active agents from the direct action of sunlight and / or heat. Finally, protective agents can also make it possible to regulate the migration of the active agent through the polymer.

The protective agents can be incorporated into any of the film layers or into a plurality of film layers.

Advantageously, the protective agents can be incorporated into a layer of polymer containing the active agent to be protected.

Advantageously also, the protective agents can be incorporated into the outermost polymer layers of the film.

In one embodiment, the film 1 is intended to transmit light from a natural and / or artificial light source. The use and the quantity of the pigments, and the thickness of the film are determined so that the film 1 is translucent enough to allow light to pass at the specific wavelength required. According to another embodiment, the film 1 is intended to reflect light from a natural and / or artificial light source. The use and the quantity of the pigments, and the thickness of the film are determined so that the film 1 is reflected a maximum of light at the specific wavelength required.

A film 1 whose characteristics allow it to both transmit and reflect a certain amount of light is however conceivable.

The film 1 can also include a reflective material. Such a reflective material makes it possible to increase the proportion and the intensity of light reflected by the film 1. The presence of reflective material is therefore particularly suitable for an embodiment in which the film 1 is intended to reflect light.

The reflective material used may for example be a white pigment, metal ions and / or any other suitable reflective material. Said reflective material can be deposited on the surface of the film 1, and / or incorporated in a layer of polymeric material. Depending on the use of the film, the reflective material can be incorporated into a substantially external layer of the film or into a substantially central layer of the film.

Advantageously, the reflective material is incorporated in a third layer between the first and the second layer of the film. This third layer is advantageously a central layer.

The term “central layer” denotes the layer which is substantially at the center of the film 1. In a film having three layers, the central layer corresponds to the second layer. In a film with four layers, the central layers or most central layers correspond to the second and third layers.

Any material deposited on the surface of film 1 constitutes a layer of said film 1 insofar as the deposition is homogeneous and continuous. The deposition of a material on the surface of the film can for example be carried out by corona printing technique.

A film 1 having a plurality of co-extruded polymer layers makes it possible to adjust the migration of the incorporated biologically active material towards the surface of the film and therefore of optimizing its bio-availability, as a function of the layer or layers in which it is incorporated, either in the surface layer, or in the interior layer or layers, or in all of the layers. It also makes it possible to locate the pigment (s) in these different layers of the film in order to optimize the reflectance.

A film having a plurality of co-extruded polymer layers also makes it possible to incorporate other ingredients such as anti UV agents, synergists such as for example Piperonyl Butoxide and / or adjuvants making it possible to control the migration and the dynamics. release of insecticide such as silica.

By playing on the combination of all these components of the film, it is possible to reduce the total amount of insecticide, pigments and other adjuvants used while maximizing their effect in terms of attractiveness of flies and insecticidal property.

It is also possible to apply a printing on a multi-layer film using for example a printing technology on polymer of the Corona type. The printing product, similar to an ink, may contain pigment alone (giving the reflectance spectrum and the desired intensity) or insecticide or both. The printing product is considered here as a layer within the meaning of the invention insofar as the deposition is homogeneous and continuous.

The presence of a pigment on the surface provides additional protection against daylight to the insecticide and / or to the synergist which can be incorporated into the different layers of the film 1. The nature and the thickness of this print can be adjusted in order to optimize the bioavailability of the insecticide (and of the synergist if necessary). Indeed, the presence of a layer of pigment on the surface slows down but does not prevent the insecticide from reaching the surface of the film. This system therefore makes it possible to increase the durability of the efficiency of the film (for example for films with a long duration of action).

The impregnated films used to date are composed at least in part of a blue fabric obtained by weaving polyester, cotton yarn or a mixture of the two. The grammage of these fabrics is of the order of 150 to 200 grams / m ² . This fabric is dyed in the mass generally hot by the technique of the dispersed pigment. The insecticide treatment is then added by soaking in a bath containing the insecticide and then dried again. The color of the fabric and its reflectance are among the essential attributes of the film. As explained above, even a slight variation in reflectance can significantly modify its performance. In the textile industry, it is difficult if not impossible to guarantee exactly the same shade from one batch to another or from one factory to another. The dyeing of the fabric by dispersed pigment therefore induces variability in the color and reflectance of the fabrics, and therefore in their attractiveness for the target insects.

Due to the nature of its surface (interlacing of woven threads), the fabric reflects less light than a polymer film.

With a treatment obtained by soaking, the insecticide is distributed homogeneously throughout the thickness of the fabric and not only on its surface. Once impregnated (bonded to the fibers by electrostatic connections), the insecticide no longer migrates spontaneously towards the surface, unlike what happens in a polymer film. Only a tiny fraction of the insecticide impregnated in the tissue is and will therefore remain bio-available. On the other hand, when the fabric is exposed to the rain, part of the insecticide can be leached and therefore lost while contaminating the environment located nearby. Finally, the soaking treatment does not allow the use of a synergist such as, for example, piperonyl butoxide, while guaranteeing a constant proportion between insecticide and synergist throughout the period of use of the fabric.

The reflectance spectrum of a film 1 according to the invention was measured and compared to those of two fabric films according to the state of the art. These different reflectance spectra are illustrated in Figure 1.

The “KLM 3 delta” film according to the invention is made of polyethylene, has a thickness of 120 microns and is composed of 5 co-extruded layers. The grammage of the film is 110 grams / m ² . Layers 1, 2, 4 and 5 are layers of high density polyethylene (HDPE) and the central layer 3 and a mixture of low density polyethylene (LDPE) and linear low density polyethylene (LLDPE) in equal proportion. Layers 1 and 5, corresponding to the outer layers, contain an insecticide such as deltamethrin. Layers 2 and 4 contain a blue pigment. The central layer 3 contains a white pigment. The nature of the pigment used, their concentration and their location in the different layers of the film make it possible to precisely adjust the spectrum and the intensity of the reflectance. Each of the layers of the “KLM 3 delta” film also includes a protective agent, in particular a UV stabilizer. The thickness of the layers can be adjusted according to the desired properties. In the case of the “KLM3 delta” film, the thickness is respectively, from the outside, of 10, 30, 40, 30 and 10 microns.

As illustrated in FIG. 1, the reflectance spectrum of the film 1 according to the invention (curve C1 corresponding to the film “KLM3 delta”) has a higher peak than those of the spectra of the films in fabrics (C2, C3) around 460nm. This reflects a greater percentage of light reflected by the film and therefore a greater intensity of light reflected in the wavelength sought by the film 1 according to the invention compared to fabric films. This greater intensity has the effect of attracting a greater number of insects.

In FIG. 1, it can also be seen that the peak of the reflectance spectrum of the film according to the invention (C1) is narrower than those of the spectra of the tissue films (C2, C3) compared. The narrowness of a peak can be determined by measuring its width at mid-height. This greater narrowness of the peak at the target wavelength results in a better controlled color and has the effect of more specifically attracting the target insects.

The presence of a narrow peak combined with a higher reflectance constitutes in fact a synergistic effect making it possible to attract more specifically the targeted insects and this in greater quantity.

This higher intensity of the reflectance obtained with the plastic films is also highlighted in FIG. 2a, where films of fabric and plastic are photographed side by side. The films are here placed on a black surface and exposed to natural light. The light visible in the photograph in FIG. 2a therefore corresponds to reflected light.

Similarly, the transmittance of a film according to the invention is compared to that of the two fabric films according to the state of the art. These transmittances are illustrated in Figure 2b. For this comparison, the films are fixed to a window and exposed to natural light passing through. The visible light in the photograph in FIG. 2b therefore corresponds to essentially transmitted light.

The reference “Burma” corresponds to a synthetic fabric film. The reference “TDV023” corresponds to a film in cotton-blend fabrics.

The reference “Sample 2 delta” corresponds to a film 1 according to the invention for use in front of a light source. This film comprises 5 layers of polyethylene, layers 1 and 5 comprising a specific blue pigment, layers 2 and 4 comprising an insecticide such as deltamethrin and the central layer comprising no additive other than an anti-UV protective agent present in the 'all layers. The reference “Sample 2” corresponds to the same film, without insecticide.

The reference “KLM 3 delta” corresponds to a film according to the invention for outdoor use. The composition of this film corresponds to that described above. The reference “KLM 3” corresponds to the same film, without insecticide. The films for outdoor use (KLM3 and KLM 3 delta) have been designed so as to have both good reflectance and good transmittance so that the film performs well regardless of the location of the light source, and therefore all hours of the day. The films for indoor use, behind a light source (Sample2), have been designed to have excellent transmittance so that the specific light intensity transmitted is as high as possible.

It can be seen that the transmittance of the fabric films (Burma and TDV023) is very low compared to the films according to the invention.

These films were compared in "real conditions", placed in open fields and on farms. A transparent and colorless polymer film coated with glue is placed on the area of the films compared. The presence of glue on the surface of the film makes it possible to visualize the impact zones of insects, as illustrated in Figure 6, and to count the insects attracted by said films. The results of these trapping tests are given in the table below.

The results in Table 1 indicate that the film 1 according to the invention attracts a greater number of target insects. This result confirms the influence of reflectance and transmittance on the film's ability to attract insects. Table 1: comparison of the attractiveness of target insects of a film 1 according to the invention and of a film according to the state of the art (tissue)

Among the insects attracted by the film 1 according to the invention, the non-targeted insects represent a smaller proportion (0.17%) than for the fabric film tested.

(0.20%). This confirms the influence of the wavelength and the fineness of the reflectance / transmittance peak of the reflectance / transmittance spectra of the film according to the invention. Thus, the film according to the invention, by virtue of its polymer composition, makes it possible to attract more insects and allows greater specificity for the target insects. Advantageously, the polymer material used is polyethylene (PE). PE has good resistance to climatic conditions and has a high reflectance, which is particularly advantageous in an insect attraction film.

As mentioned above, the film 1 according to the invention advantageously comprises a plurality of layers of juxtaposed polymeric materials. These different layers can be made of identical or different polymer materials. According to this embodiment, the surface of the film is defined by the outermost polymer layers of the film or by the components deposited on their surface.

Each active agent, protective agent and reflective material can be incorporated into, or onto the surface of the film. For example, a biological active agent and a pigment can be mixed and incorporated into the same layer of polymeric materials, which allows a simplification of the manufacturing process.

However, when several pigments, active agents, protective agents and / or reflective materials are incorporated in the same layer of polymeric material, it is necessary that these different components are compatible with each other. Indeed, it is possible that an insecticide can be degraded by a particular pigment or its speed of migration through the polymer is modified. In such a case, it is then impossible to incorporate both the insecticide and the pigment in question in the same layer of polymeric material.

Advantageously, only one component from pigments, active agents, protective agents or reflective materials is incorporated into a given polymer layer. A given layer corresponds to a given function, so a multi-functionalized multilayer film is obtained. Any interference between incorporated components (pigments, active agents, protective agents and reflective materials) is thus avoided. This embodiment is particularly advantageous when the active agents used are relatively sensitive and could be altered by direct contact with another component of the film.

When each component of the film is incorporated into a separate polymer layer, each of the layers can be produced separately. All layers are subsequently laminated and / or extruded so as to form a single film. This facilitates the manufacturing process and better controls the composition of the film.

Advantageously, the active agent is incorporated into the outermost polymer layers of the film. Thus, the active agent incorporated in the polymer and migrating to the surface of the film will be more readily available on the surface of the film or any other control device produced with this film.

According to one embodiment, the outer layers of the film have a thickness of 10 μm and contain an insecticide. Said film has an insecticide concentration of 3% w / w on its surface. In comparison, for a film made of fabric and comprising the same amount of insecticide per unit area, the useful concentration of insecticide on the surface of the fabric will be only 0.4%, or 87% lower than that of the film. according to the invention. Thus, the incorporation of active agent in the outer polymeric layers of the film makes it possible either to increase the concentration of said active agent on the surface for the same amount of insecticide used, or to decrease the total amount of insecticide incorporated in the film , for the same concentration on the surface of the film.

Likewise, the pigment can advantageously be incorporated into the outermost polymer layers of the film in order to protect the bioactive agents which would be stored in the inner layers.

Advantageously, the film 1 comprises a plurality of layers of polymer, the thickness of the various layers of polymer being configured so that the film 1 has a substantially symmetrical structure. For example, for a film comprising 5 layers of polymer, the thickness of the layers is respectively, starting from the outside, of 10, 20, 50, 20 and 10 μm. For a film comprising 4 layers of polymer, the thickness of the layers can be respectively, from the outside, 40, 60, 60 and 40 μm. Film 1 thus presents a plane of symmetry. The thicknesses of the polymer layers are equal, on either side of the plane of symmetry, two by two away from said plane of symmetry. Such a substantially symmetrical structure makes it easier to extrude and laminate the different layers. This makes the film manufacturing process easier.

Advantageously also, the film 1 comprises a third layer comprised between the first and the second layer, said third layer comprising in polymeric material limiting the migration of the active agent. The polymeric material limiting the migration of the active agent advantageously comprises polyamide (PA). This polymer is distinct from the polymer or polymers constituting the other layers, said other polymers allowing the migration of an active agent. In particular, said polymer limiting the migration of the active agent comprises polyamide. Said third layer is advantageously a central layer of the film 1.

The thickness of the film is also a parameter which can be decisive depending on the embodiment and the intended use for the film.

The film being intended to be used in an outdoor environment, it must have a thickness which gives it sufficient rigidity to withstand wind and weather conditions and also flexibility allowing it not to break under the effect of mechanical stresses.

When the film is intended to transmit light from a natural and / or artificial light source, its thickness can be adjusted so that it is sufficiently translucent to allow light to pass through.

Advantageously, the film has a thickness of between 30 μm and 300 μm. The films used to carry out the reflectance and transmittance tests, the spectra and photos of which are given in FIGS. 1 and 2 have a thickness of 120 μm.

The thickness of the film 1 as well as its shape and its surface can vary depending on the desired arthropod control tool.

According to an embodiment of the invention illustrated in Figure 3, the surface of the film 1 has a single area 10. Said unique zone 10 is defined by the presence specific pigments conditioning the reflectance and transmittance of a light having the desired wavelengths.

According to a second embodiment of the invention illustrated in Figure 4 the surface of the film 1 consists of two zones. A first central zone 12 is defined by the presence of certain pigments and a second peripheral zone 14 is characterized by the presence of other pigments. The term zone here refers to part of a surface. The term "central" is used here in opposition to the term "peripheral", said central zone is therefore not necessarily centered on the surface of the film.

Advantageously, the central zone consists of a layer of pigments printed on the surface of the film. If a film according to this embodiment (central zone and peripheral zone) were to be produced without printing technique, it would be necessary to weld the layer corresponding to the central zone with the rest of the film, which is technically and economically much more binding (MD). A printing technique is therefore particularly suitable here because it makes it much easier to combine areas of different colors.

Following research and a series of tests in the field, the Applicant has found that a film having a colored zone at the attractive specific wavelength of insects surrounded by a white zone makes it possible to obtain better results both by the number of insects attracted than by the specificity of the target insects. This improvement seems to be due to an optimized contrast effect between the specific color area and the white area which reflects non-specific light.

The film 1 according to the invention is suitable for attracting harmful target arthropods from animals and man. In particular the film 1 is suitable for attracting blood-sucking insects.

A first type of target insect is blood-sucking flies such as tsetse flies, stomoxes, tabanids and others. According to one embodiment, the film in which the latter is intended to target blood-sucking flies, the nature and the amount of the pigment used are determined so that the reflected and / or transmitted light has a wavelength peak between 450 nm and 460 nm. In fact, blood-sucking flies are particularly attracted by the wavelengths included in this range. It also appears that these 450-460nm wavelengths have a repellent effect on non-target insects, which gives a better specificity of the attractiveness of a screen associating a reflecting zone or transmitting this wavelength to a zone reflecting or transmitting another wavelength.

Films intended for the attraction and control of blood-sucking flies are advantageously suitable for external use during the day. The light source is then a natural source like the sun, said light will be mainly reflected by the film. Such a film advantageously has a plurality of layers of polymer including a central layer in which is incorporated a reflective material such as a white pigment or metallic particles. The active agent used in such a film is advantageously an insecticide incorporated in the outer polymer layers. However, when the film is intended to be used in an open environment, to guarantee its attractiveness whatever the position of the light source relative to the film, it is advantageous to associate with good reflectance, good transmittance, which is possible by finely dosing a white dye in the central layer of the film.

A second type of target insect is mosquitoes. According to an embodiment of the film in which the latter is intended to attract mosquitoes, the nature and the amount of the pigment used is selected so that the reflected and / or transmitted light has a wavelength peak between 330 nm and 390 nm. In fact, mosquitoes are particularly attracted by the wavelengths included in this range. Depending on the hours of activity of the target species, the film can be designed and used for its good reflectance and transmittance (during the day) or only for its high transmittance (at night, in combination with an artificial light source). According to another embodiment, the film 1 according to the invention is configured so as to repel target insects. The film's repellent effect can be obtained by the use of repellent olfactory agents or by the use of specific pigments. For example, a film 1 according to the invention comprising a green pigment selected so that the reflected and / or transmitted light has a wavelength peak around 520 nm has a repellent effect on the tsetse fly.

Films intended for the attraction and control of blood-sucking insects can advantageously be adapted for use in mainly or exclusively transmitted light. In the case of use at night, the light source is an artificial source such as a lamp, said light will be reflected (direct lighting carried on the film) or transmitted (lighting placed behind the film) or transmitted and reflected by a combination of of them. Such a film can in particular be adapted to be fixed to a window of a dwelling, outside. The light coming from inside the house is then transmitted by the film and mosquitoes or other hematophagous insects are attracted by this transmitted light. Conversely, such a film can in particular be adapted to be fixed on a window of a stable, inside. The natural light coming from outside the barn is then transmitted by the film and the blood-sucking insects which are inside the barn are attracted by this transmitted light.

The examples of films given below are not limiting and are given by way of illustration only. The different layers of these examples of film production are described from a first side of the film to a second side of the film.

Example 1: A film comprising two layers, one layer C1 of which is made of polymer material with a biological active agent (insecticide, acaricide, attractant, repellant, etc.) incorporated into the polymer and a layer C2 consisting of a specific light-reflecting pigment in a defined spectrum. This second layer is added by printing (Corona type for example), induction, grafting or any suitable industrial process.

Example 2: A film comprising two layers, a layer C1 of which is made of polymer material with, incorporated into this polymer a specific pigment reflecting light in a defined spectrum, and a layer C2 consisting of a biological active agent (insecticide, acaricide, attractant, repellent ...). This second layer is added by printing (Corona type for example), induction, grafting or any suitable industrial process. Printing can be applied on both sides of the film which then has 3 layers in total.

Example 3: a polymer film coextruded with three layers of polymer, layers C1 and C3 containing a biological active agent as defined above incorporated in the polymer, and a layer C2 situated between layers C1 and C3 and containing a specific pigment as defined above incorporated into the polymer.

Example 4: a polymer film coextruded with three layers of polymer, layers C1 and C3 containing a biological active agent and a pigment as defined above incorporated in the polymer, and a layer C2 situated between layers C1 and C3 and containing a reflective material (titanium oxide, metal ions, etc.) incorporated into the polymer. The function of the layer C2 is to increase the amount of light reflected by the film.

Example 5: a polymer film co-extruded with three layers of polymer, the layers C1 and C3 containing a biological active agent as defined above incorporated in the polymer, and a layer C2 situated between the layers C1 and C3 and containing a reflective material (titanium oxide, metal ions ...) incorporated in the polymer. The function of the layer C2 is to increase the amount of light reflected by the film. A specific pigment as indicated above is applied to the surface of the film by printing, induction, grafting or any other ad hoc industrial process establishing the total number of layers at 4 or 5 depending on whether the pigment is applied to only one side of the film or both.

Example 6: a co-extruded film with five layers of polymer, layers C1 and C5 containing a specific pigment as defined above incorporated into the polymer, layers C2 and C4 containing a biological active agent as defined above above, and the central layer C3 containing nothing but polymer. The polymer of layer C3 may be of the same nature as that used for the other layers (for example polyethylene) or of a different nature, for example more mechanically resistant and limiting the migration of the active agent towards the central layer of the film (by example of polyamide). The biological active agent of layers C2 and C4 can be incorporated alone or combined with a specially chosen adjuvant (such as silica) to modulate its speed of migration towards the surface of the film through layers C1 and C5.

Example 7: a co-extruded film with five layers of polymer, layers C1 and C5 containing a specific pigment as defined above incorporated into the polymer in admixture with a potentiating agent such as, for example, piperonyl butoxide, layers C2 and C4 containing a biological active agent as defined above and the central layer C3 containing a reflective substance such as for example titanium oxide or metal ions. The polymer of the central layer C3 can be of the same nature as that used for the other layers or of a different nature, in particular more mechanically resistant (for example polyamide). The biological active agent of layers 2 and 4 can be incorporated alone or combined with a specially selected adjuvant (such as silica) to modulate its speed of migration towards the surface of the film through layers C1 and C5.

Example 8: a co-extruded film with five layers of polymer, layers C1 and C5 containing a specific pigment as defined above incorporated into the polymer in admixture with an olfactory attractant such as R-Octenol, layers C2 and C4 containing a biological active agent as defined above, and the central layer C3 containing a reflective substance such as for example titanium oxide or metal ions. The polymer of layer C3 can be of the same nature as that used for the other layers or of a different nature, for example polyamide which is more mechanically resistant and less permeable to biological active agents. The biological active agent of layers C2 and C4 can be incorporated alone or combined with a specially chosen adjuvant (such as silica) to modulate its speed of migration towards the surface of the film through layers C1 and C5. The examples mentioned above clearly illustrate the possibility of obtaining a very large number of possible combinations by varying the number of layers and by applying, if necessary, a pigment or a biological active agent to the surface of the film or by incorporating them into the film. one and / or the other of the polymeric layers. This combination of different layers provides several important advantages:

- The possibility of treating only certain layers of the film with the biological active agent so as to limit the total amount necessary while maintaining the minimum biologically active concentration on the surface of the film. The localization of the active material inside the film makes it possible, if necessary, to regulate its migration towards the surface and therefore to increase the effective lifetime of the film by limiting or delaying the deleterious effects of sunlight.

- The possibility of combining a potentiator of the active ingredient such as a synergist such as for example piperonyl butoxide (PBO) either mixed directly with said active ingredient or located in a different layer.

- The possibility of combining several pigments in the same layer or different layers to very precisely adjust the spectrum of reflected light. It is also possible to add, for example in the layers located just under those containing the pigment (s), a reflective material whose effect will be to considerably increase the amount of light reflected and therefore the attractiveness of the film.

- The possibility of varying if necessary the total thickness of the film without having to proportionally increase the amount of biologically active material necessary to functionalize it.

- The possibility of combining different polymers such as polyethylene and polyamide (nylon) in order to reinforce the mechanical resistance of the films.

- The possibility of reinforcing the mechanical resistance of the films (for example with a central polyamide layer) while avoiding the diffusion, and therefore the loss in terms of bioavailability, of the active agents which are in the peripheral layers towards this central layer. In general, it is preferable to produce co-extruded films containing an odd number of layers (3, 5, 7 or 9) so that the distribution of the layers on either side of the central layer be symmetrical. In the case where different polymers are used in the same film, the connection between the layers of different nature is ensured by the use of a particular polymer such as TIE. The latter may constitute one or more of the layers of the film (generally very thin, of the order of 5 microns) or be mixed with the polymers which constitute the layers.

The thickness of multi-functionalized multilayer films is generally between 30 and 300 microns. The thickness of each layer can vary depending on requirements. These layers are generally equal to or greater than 5 microns.

The invention also relates to a screen 100 for controlling arthropods harmful to plants, animals and humans, comprising at least one film 1 as described above as well as a system for attaching said film 1.

A screen 100 according to the invention is shown in Figure 5.

The system for attaching the screen 100 illustrated in FIG. 5 includes stakes 110 as well as tensioners 112 connecting the film 1 and the stakes 110. The stakes 110 are intended to be fixed in the ground and to hold the film 1 in a substantially vertical plane using the tensioners 112. The tensioners 112 here connect the film 1 by means of PVC pipes housed in welded folds, to the upper and lower parts of the film 1.

As mentioned above, the thickness of the film 1 as well as its shape and its surface can vary depending on the desired arthropod control tool. For example, for the production of a screen 100 according to the invention, a film of rectangular or square shape of about one meter on a side will be particularly suitable. These shapes and dimensions are given for information only.

It is possible to make other tools for controlling harmful arthropods by using a film 1 of reduced or larger surface area. Such tools can for example be coverings for tunnel greenhouses.

Claims

1. Film (1) for arthropod control tools harmful to plants, animals, or man, making it possible to reflect and / or transmit light coming from a natural and / or artificial source, said film (1) comprising at least one pigment so that the light reflected and / or transmitted by said film (1) has a specific wavelength peak capable of specifically attracting or repelling the targeted arthropods and at least one agent active agent for killing and / or sterilizing or repelling target arthropods when they come into contact with the film (1), characterized in that said film (1) comprises a plurality of juxtaposed layers including a first layer of suitable polymer material allowing the migration of said active agent, one of the components among the pigment and the active agent being incorporated into said first layer of polymer material, the other component being either deposited on the surface of said first re layer of polymer material so as to form a second layer, or incorporated into a second polymer layer capable of allowing the migration of said active agent.

2. Film (1) according to the preceding claim, characterized in that the active agent is incorporated in the first layer of polymer.

3. Film (1) according to one of the preceding claims, characterized in that the polymer material capable of allowing the migration of an active agent is selected from polyethylene terephthalate (PET), polyethylene (PE) or polypropylene ( PP).

4. Film (1) according to one of the preceding claims, characterized in that it comprises a reflective material such as a white pigment, metallic particles or any other suitable reflective material.

5. Film (1) according to claim 4, characterized in that a single component among the pigments, active agents and reflective materials is incorporated in a given polymer layer.

6. Film (1) according to one of claims 2 to 5, characterized in that the pigment is incorporated in the outermost polymer layers of the film (1).

7. Film (1) according to one of the preceding claims, characterized in that it has a thickness between 30 µm and 300 µm.

8. Film (1) according to one of the preceding claims, characterized in that it comprises a third layer between the first and the second layer, said third layer comprising polymer material limiting the migration of the active agent, said polymer material comprising polyamide (PA).

9. Film (1) according to one of claims 2 to 8, characterized in that the polymer layer comprising the active agent also comprises an adjuvant making it possible to modulate the migration speed of the active agent in the film (1 ), said adjuvant possibly being silica.

10. Film (1) according to any one of the preceding claims, characterized in that at least one of its layers of polymeric material comprises a protective agent, in particular a UV stabilizer.

11. Film (1) according to any one of the preceding claims, characterized in that one and / or the other of its surfaces comprises a first central zone (12) defined by the presence of a first pigment and a second peripheral zone (14) containing a second pigment.

12. Film (1) according to one of the preceding claims, characterized in that the nature and the quantity of the pigment (s) used are selected so that the reflected and / or transmitted light has a wavelength peak between 450 nm and 460 nm.

13. Film (1) according to one of the preceding claims, characterized in that the nature and the quantity of the pigment (s) used are selected so that the reflected and / or transmitted light has a wavelength peak between 330 nm and 390 nm.

14. Screen (100) for controlling arthropods harmful to plants, animals, and humans, comprising at least one film (1) according to one of claims 1 to 12 and a system for attaching said film. (1).