Use of plastic products comprising PBSA and an insect repellent for repelling pests

Abstract

The present invention relates to the use of plastic products comprising PBSA and an insect repellent for repelling pests. The insect repellent is chosen from essential oils, aerial parts of sweet potato plant and any mixture thereof. The invention also relates to such a plastic product, and also to a process for manufacturing such a plastic product, preferably by extrusion.

Description

[0001] Use of plastic products comprising PBSA and an insect repellent for repelling pests

[0002] TECHNICAL FIELD OF THE INVENTION

[0003] The present invention relates to the use of polybutylene succinate adipate (PBSA) plastic products for repelling pests, such as aphids, in particular in agricultural applications.

[0004] TECHNOLOGICAL BACKGROUND

[0005] Each year, crops are subjected to dangerous harmful insect species resulting in considerable economic losses (estimated at 250 billion euros worldwide) and potentially dangerous risks due to the use of chemical pesticides for soils, groundwater and human health. For example, aphids constitute the taxa which are the most harmful to all cultivated plants. In fact, their control is difficult since they exhibit a specific dietary behaviour and also an unusual reproductive biology. Current protective strategies based on the intensive use of chemicals are considered as unsustainable for the development of a sustainable agriculture due to their negative impact on the environment and human health. Furthermore, this approach has led to the development of resistance of insects to phytosanitary treatments. For these reasons, the French government published, in October 2015, the "Ecophyto II" programme in order to achieve the objective of reducing by half the use of phytopharmaceutical products by 2025 by encouraging new solutions for a sustainable agriculture based on innovative biological molecules. In recent years, another alternative for reducing the development of resistance of insects to the use of chemicals and pesticides has emerged through the development of physical barriers, such as the use of anti-insect nets which are mainly based on polyethylene. However, this is a palliative approach involving the management of these materials at the end of life, which materials are neither biodegradable nor compostable. Such polymer materials require steps of separation of plant debris (components, soil, rocks, water, adsorbed biofilm, and the like) by intensive washing operations which consume a large amount of water before being retreated.

[0006] Currently, European countries are encouraging industry to reconsider its production methods in order to reduce the use of fossil resources and to minimize the environmental impact of products throughout their life cycle. For these various reasons, new French and European regulations and also environmental challenges, such as plastic pollution, represent a real opportunity for the development of new biobased and / or compostable materials. Consequently, biobased materials are mainly based on components from crops, that is to say from annually renewable resources, such as sugar cane, maize, oils, and the like. Nevertheless, these biobased materials do not exhibit sufficient intrinsic properties to be easily transformable by conventional melt-state transformation processes, such as melt spinning or extrusion and for applications requiring combined performance qualities, such as mechanical properties (stress and elongation at equilibrium break). The water barrier properties and additional functionalities, such as resistance to insects, must also be taken into account.

[0007] PBSA, or poly(butyl succinate), more commonly referred to as polybutylene succinate adipate, is an aliphatic polyester obtained by copolymerization of 1,4-butanediol, succinic acid and adipic acid monomers. It is a polymer of choice for use in the agriculture because it is a biopolyester, today biobased to 35%. In particular, the succinic acid used for the synthesis of PBSA can be biobased. In addition, PBSA is biodegradable under varied conditions, such as industrial composting, domestic composting and in the soil. Biodegradability is defined in particular in NF EN 13432:2000. The high flexibility of PBSA makes it possible for it finally to be used for the manufacture of films.

[0008] In order to confer particular properties to polymeric products, such as PBSA plastic products, it may be desirable to incorporate, in the plastic product, additives such as dyes, fillers, plasticizers, compatibilizers, agents which modify the mechanical properties or anti-pest active agents, such as insecticides and / or insect repellents.

[0009] W02009 / 095624 describes the use of 3,5-dicaffeoylquinic acid and of its derivatives for the repulsion or the removal of various species of aphids. These compounds are extracted from the non-tuberized roots of sweet potato plant.

[0010] Essential oils are also known as having a repellent activity against pests, such as aphids. For example, JPH09110623 describes the use of a mixture of specific essential oils for repelling aphids.

[0011] These active agents of natural origin are known to have advantageous insect-repellent properties against aphids. It would thus be advantageous to incorporate these insect-repellent active agents in PBSA plastic products, such as PBSA films. The products obtained would exhibit the twofold advantage of being repellent to insects, such as aphids, and of being biodegradable. In addition, active agents of natural origin, such as essential oils and aerial parts of sweet potato plant, have the task of replacing conventional chemical pesticides.

[0012] PBSA plastic products, in particular PBSA films, are conventionally manufactured by extrusion, which requires melt processing, involving heating to temperatures of greater than 100°C. Certain additives, such as insect repellent active agents, may be at least partially degraded at such temperatures.

[0013] To the knowledge of the Inventors, no process has been described which would make it possible to incorporate, in PBSA plastic products, such as PBSA films, insect repellent active agents of natural origin chosen from essential oils and aerial parts of sweet potato plant without degrading said active agents and thus without affecting their insect repellent properties. It would thus be advantageous to provide processes for manufacturing PBSA plastic products, such as PBSA films, making it possible to incorporate such insect repellent active agents in the plastic product without degrading them. Advantageously, these processes would involve melt processes, in particular extrusion, which are the processes of choice for the shaping of PBS A plastic products.

[0014] In this context, the Inventors have demonstrated that it is possible to obtain high levels of pest repulsion with plastic products comprising a PBSA matrix in which an insect repellent active agent is incorporated, this insect repellent active agent being chosen from essential oils, aerial parts of sweet potato plant and mixtures thereof. In addition, they have demonstrated that the insect repellent activity of the active agent is not or only very slightly affected by the extrusion used to manufacture the plastic product.

[0015] SUMMARY OF THE INVENTION

[0016] Thus, a first object of the present invention is the use of a plastic product comprising polybutylene succinate adipate (PBSA) and an insect repellent active agent chosen from essential oils, aerial parts of sweet potato plant and any mixture thereof, for repelling pests, such as insects.

[0017] In some embodiments, the plastic product is chosen from the group consisting of anti-insect nets, covers for agricultural fields, plastic covers, storage bags and gardening pots.

[0018] In some embodiments, the pests are insects of the Aphidoidea family, such as aphids.

[0019] In other embodiments, the essential oil is chosen from the group consisting of basil essential oil , mint essential oil, peppermint essential oil, cinnamon essential oil, such as Chinese cinnamon essential oil, French marigold essential oil, rosemary essential oil, thyme essential oil, oregano essential oil and any mixture thereof.

[0020] In some embodiments, the plastic product has a thickness of less than 100 micrometres.

[0021] In some embodiments, the aerial parts of sweet potato are a ground material of leaves of sweet potato plants.

[0022] In some embodiments, the plastic product comprises at least one other polymer in addition to PBSA, preferably PHB, PHBV or any mixture thereof.

[0023] In some embodiments, the amount of the insect repellent active agent is from 0.5% to 5% by weight, with respect to the total weight of the PBSA + insect repellent active agent mixture.

[0024] In some embodiments, the insect repellent active agent is a mixture of at least one essential oil and aerial parts of sweet potato plant.

[0025] In some embodiments, each of the at least one essential oil and aerial parts of sweet potato plant is included in a proportion of between 1% and 5% by weight, with respect to the total weight of PBSA and the insect repellent active agent mixture, preferably the at least one essential oil is included in a proportion of 1% by weight and the aerial parts of sweet potato plant are included in a proportion of 4% by weight, with respect to the total weight of PBS A and the insect repellent active agent mixture.

[0026] In some embodiments, the at least one essential oil is cinnamon essential oil or mint essential oil.

[0027] In some embodiments, the plastic product comprises a polymeric matrix comprising PBSA and the insect repellent active agent, the insect repellent active agent being distributed in the polymeric matrix comprising the PBSA.

[0028] In some embodiments, the plastic product is manufactured by a melt technique, such as extrusion, in particular conventional extrusion or blown film extrusion.

[0029] Another object of the invention is a plastic product, in particular a plastic film, comprising PBSA and an insect repellent active agent chosen from essential oils, aerial parts of sweet potato plant and any mixture thereof.

[0030] Another object of the invention is a process for manufacturing a plastic product comprising polybutylene succinate adipate (PBSA) and an insect repellent active agent chosen from essential oils, aerial parts of sweet potato plant and any mixture thereof, comprising a step of melt extrusion of a mixture comprising the polybutylene succinate adipate (PBSA) and the insect repellent active agent.

[0031] BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure l is a photograph of the device used for the tests of choice by repulsion.

[0033] Figure 2 is a comparative thermogram of sweet potato leaves, on the one hand, and of DiCQ, on the other hand.

[0034] Figure 3 is the thermogram of the film comprising 10% by weight of sweet potato leaves.

[0035] Figure 4 is the thermogram of the film comprising an amount of pure DiCQ equivalent to that contained in 10% by weight of sweet potato leaves.

[0036] Figure 5 comprises the thermograms of essential oils alone, of PBSA alone and of mixtures of PBSA + essential oils at 1% by weight (left) and 5% by weight (right). The essential oils are denoted as follows: BAS = basil; SPE = mint; PEP = peppermint and CIN = Chinese cinnamon.

[0037] Figure 6 is a histogram showing the proportion of the number of aphids on the side of the control (thus being subjected to the repellent effect) for PBSA films comprising 1%, 2%, 3%, 4% or 5% of each essential oil. The essential oils are denoted as follows: BAS = basil; SPE = mint; PEP = peppermint and CIN = Chinese cinnamon.

[0038] Figure 7 is a graph showing the biodegradation, as a function of time, of pure PBSA film and PBSA films comprising 1% by weight (left) or 5% by weight (right) of each essential oil. The essential oils are denoted as follows: BAS = basil; SPE = mint; PEP = peppermint and CIN = Chinese cinnamon.

[0039] DETAILED DESCRIPTION

[0040] Use of the plastic product

[0041] A first object of the invention is the use of a plastic product comprising polybutylene succinate adipate (PBSA) and an insect repellent active agent chosen from essential oils, aerial parts of sweet potato plant and any mixture thereof, for repelling pests, such as insects.

[0042] The term "insect repellent active agent" denotes a compound or a mixture of compounds which has a repellent action towards at least one type of insect when it is used in a suitable amount. Insecticides are also considered as examples of insect repellent active agents according to the invention.

[0043] The term ''pests'' denotes animals, all or part of the activities of which have effects which are detrimental to the satisfactory progression of certain human activities (agriculture, fish farming, hunting management, forestry, and the like). Preferably, the pests are insects.

[0044] The insects may be insects of any type. In particular, they include aphids (family of the Aphidoidea), whiteflies, mealybugs, flies and mosquitoes. In some embodiments, the insects are aphids.

[0045] The use of the plastic product is preferably a use in the agricultural field.

[0046] Plastic product

[0047] The term "plastic product” denotes a product comprising at least one polymer, such as plastic sheet, tube, rod, profiled element, form, solid block, fibre, and the like. Preferably, the plastic product is a manufactured product, such as rigid or flexible packagings (containers, cups, and the like), agricultural films, bags, disposable articles or similar, and the like. The plastic product may contain additional substances or additives, such as plasticizers, minerals, organic fillers, compatibilizers or colorants. The term "plastic product” also encompasses granules, extruded strips, fibres, films, powders, and the like, which may subsequently be shaped in order to obtain the manufactured products.

[0048] Examples of plastic products according to the present invention include, without limitation, pipes, tapes, irrigation connectors, plastic films for the covers of greenhouses and tunnels, water storage tanks, mulch films, anti-insect nets, covers for agricultural fields, plastic covers, storage bags and gardening pots, preferably anti-insect nets or mulch films.

[0049] A "polymer” refers to a chemical compound or to a mixture of compounds, the structure of which consists of several repeat units, referred to as monomers, which are linked via covalent chemical bonds. In the context of the invention, the term "polymer” denotes such a chemical compound or mixture of compounds used in the composition of a plastic product.

[0050] The plastic products used according to the invention comprise PBSA. The PBSAused may be of any molar mass and of any density which are suitable for shaping in the form of a plastic product. Preferably, the molar mass of the PBSA is of between 20 000 g / mol and 80 000 g / mol, for instance between 40 000 g / mol and 60 000 g / mol. Preferably, the density of the PBSA is of between 1200 and 1300 kg / m3, preferably between 1230 and 1260 kg / m3. The PBSA may exhibit any molar ratio of the succinate units to the adipate units. Preferably, the molar ratio of the succinate units to the adipate units is of between 0.9:0.1 and 0.5:0.5; for example it may be approximately 0.75:0.25. The PBSA used may or may not be of food grade. For example, it may be biobased PBSA, such as BioPBS® PBSA materials commercialized by Mitsubishi Chemical or Bionolle® PBSA materials commercialized by Resonac.

[0051] The thermal and mechanical properties of the PBSA plastic product, in particular PBSA film, are preferably not affected by the incorporation of the insect repellent active agent in the plastic product.

[0052] The plastic product used according to the invention can be considered as comprising a polymeric matrix comprising PBSA and an insect repellent active agent. The insect repellent active agent is preferably distributed in the polymeric matrix comprising the PBSA, preferably distributed homogeneously in the polymeric matrix comprising the PBSA.

[0053] In some embodiments, the plastic product comprises PBSA as sole polymer. Preferably, the plastic product comprises a polymeric matrix consisting of PBSA and of the insect repellent active agent.

[0054] In some embodiments, the plastic product comprises at least one other polymer in addition to PBSA. The at least one other polymer may be, for example, a polyolefin, such as polyethylene or polypropylene, starch, a polyester, such as polybutylene adipate terephthalate PBAT, poly-P- hydroxybutyrate PHB, polyhydroxybutyrate-co-hydroxyvalerate PHBV or polylactic acid PLA. In one embodiment, the at least one other polymer is chosen from the group consisting of PHB, PHBV and any mixture thereof. Preferably, when the plastic product comprises at least one other polymer in addition to PBSA, said at least one other polymer is biodegradable and / or compostable. When the plastic product comprises at least one other polymer in addition to PBSA, the ratio of the PBSA to the other polymer may vary to a great extent. Preferably, the ratio of the PBSA to the other polymer in the plastic product is of between 5:95 and 95:5 by weight, with respect to the total weight (PBSA + other polymer). Preferably, the PBSA represents at least 50% by weight, with respect to the total weight (PBSA + other polymer).

[0055] In some embodiments, the PBSA and the at least one other polymer are mixed in the plastic product, in which case the insect repellent active agent is incorporated in the PBSA / other polymer mixture. In other embodiments, the PBSA and the at least one other polymer represent two distinct parts of the plastic product. For example, if the plastic product is a multilayer film, the PBSA and the at least one other polymer may each represent a layer of the film. In such a case, the insect repellent active agent is preferably incorporated only in the PBSA.

[0056] In some embodiments, the plastic product comprises several layers (multilayer product) and the PBSA and the insect repellent active agent are included in one and the same layer.

[0057] The plastic product may be manufactured by any suitable technique known in the art. In some preferred embodiments, the plastic product is manufactured by a melt technique, in particular conventional extrusion, extrusion-blow moulding or blown film extrusion, for instance by conventional extrusion or blown film extrusion.

[0058] The amount of insect repellent active agent in the plastic product may vary to a great extent. Preferably, the insect repellent active agent is included in a proportion of between 0.5% and 10%, preferably between 0.5% and 5%, for instance between 1% and 5%, by weight, with respect to the total weight of the polymeric matrix, in particular the PBSA matrix, and the insect repellent active agent.

[0059] Thus, one object of the invention is a plastic product, in particular a plastic film, comprising PBSA and an insect repellent active agent chosen from essential oils, aerial parts of sweet potato plant and any mixture thereof. Preferably, the insect repellent active agent is included in a plastic matrix consisting essentially of, in particular consisting of, PBSA.

[0060] In some embodiments, particularly when a film is concerned, the plastic product has a mean thickness of less than 100 microns, preferably a mean thickness of less than 80 microns, especially a mean thickness of less than 50 microns.

[0061] Essential oil

[0062] In some embodiments, the insect repellent active agent present in the plastic product comprises at least one insect repellent essential oil.

[0063] In some embodiments, the insect repellent essential oil is chosen from the group consisting of basil essential oil, mint essential oil, peppermint essential oil, cinnamon essential oil, such as Chinese cinnamon essential oil, French marigold essential oil, rosemary essential oil and any mixture thereof. In some embodiments, the insect repellent essential oil is chosen from the group consisting of basil essential oil, mint essential oil, peppermint essential oil, cinnamon essential oil, such as Chinese cinnamon essential oil, French marigold essential oil, rosemary essential oil, thyme essential oil, oregano essential oil and any mixture thereof. In preferred embodiments, the essential oil is chosen from the group consisting of basil essential oil, mint essential oil, peppermint essential oil, cinnamon essential oil, such as Chinese cinnamon essential oil, and any mixture thereof. In other preferred embodiments, the essential oil is chosen from the group consisting of basil essential oil, mint essential oil, peppermint essential oil, cinnamon essential oil, such as Chinese cinnamon essential oil, thyme essential oil, oregano essential oil and any mixture thereof. In some embodiments, the essential oil is a mixture of thyme essential oil and oregano essential oil. In some embodiments, the essential oil is basil essential oil. In some embodiments, the essential oil is mint essential oil. In some embodiments, the essential oil is peppermint essential oil. In some embodiments, the essential oil is cinnamon essential oil, such as Chinese cinnamon essential oil. In some embodiments, the essential oil is thyme essential oil. In some embodiments, the essential oil is oregano essential oil.

[0064] The amount of essential oil in the plastic product may vary to a great extent. Preferably, the essential oil or the mixture of essential oils is included in a proportion of between 0.5% and 10%, for instance between 1% and 5%, by weight, with respect to the total weight of the polymeric matrix, in particular the PBSA matrix, and the insect repellent active agent.

[0065] Aerial parts of sweet potato plant

[0066] In some embodiments, the insect repellent active agent present in the plastic product comprises all or part of aerial parts of sweet potato plant. In some embodiments, the aerial parts of sweet potato plant are sweet potato plant leaves and / or sweet potato plant stems, preferably sweet potato plant leaves.

[0067] The sweet potato, or potato, is a species of dicotyledonous plants of the family of the Convolvulaceae, tribe of the Ipomoeeae. species Ipomoea batatas.

[0068] The aerial parts of sweet potato may be incorporated in the plastic product in any suitable form. For example, they may be introduced in their entirety or their size may be reduced, in particular to facilitate the dispersion and / or mixing in the polymeric matrix.

[0069] In some embodiments, the aerial parts of sweet potato are incorporated in the polymeric matrix in the form of a ground material. The particle size of the ground material may vary to a great extent. Preferably, the particle size is adapted to the needs of the subsequent shaping of the plastic product. Thus, when the plastic product is of low thickness, such as a film or a cover, it is preferable for the particle size to be less than the desired thickness of the plastic product.

[0070] In some embodiments, the aerial parts of sweet potato are in the form of a ground material with a particle size of less than 70 micrometres, preferably of less than 50 micrometres, for instance of less than 30 micrometres. Preferably, the particle size is not less than 0.5 micron, preferably not less than 1 micron. The term "particle size" denotes the mean size of the particles of the ground material of aerial parts of sweet potato.

[0071] The amount of aerial parts of sweet potato plant in the plastic product may vary to a great extent. Preferably, the aerial parts of sweet potato plant are included in a proportion of between 0.5% and 10%, for example between 1% and 5%, preferably about 4%, by weight, with respect to the total weight of the polymeric matrix, in particular the PBSA matrix, and the insect repellent active agent.

[0072] The aerial parts of sweet potato preferably contain DiCQ (3,5-dicaffeoylquinic acid).

[0073] In some embodiments, the insect repellent active agent is a mixture of at least one essential oil and of aerial parts of sweet potato.

[0074] Such mixture of an essential oil and aerial parts of sweet potato plant makes it possible to obtain a PBSA film with improved mechanical properties compared to a PBSA film comprising an essential oil only or aerial parts of sweet potato plant only. For instance, such a mixture makes it possible to obtain a PBSA film with an improved elongation at break compared to a PBSA film comprising an essential oil only. In addition, a mixture an essential oil, in particular cinnamon or mint essential oil, and of aerial parts of sweet potato plant may advantageously result in a PBSA film having an improved Young’s modulus compared to a PBSA film comprising aerial parts of sweet potato plant only.

[0075] Moreover, a plastic product comprising a mixture of an essential oil and aerial parts of sweet potato plant maintains its insect-repellent activity for a longer period of time than a plastic product comprising an essential oil only. For example, a plastic product comprising such a mixture may keep its insect-repellent activity for at least 55 days, or even for at least 90 days.

[0076] The weight ratio of the at least one essential oil to the aerial parts of sweet potato plant may vary to a great extent. It may be of, for example, between 5:95 and 95:5, especially between 30:70 and 70:30; in particular, it is approximately 50:50 by weight.

[0077] In some embodiments, the insect repellent active agent is a mixture of at least one essential oil and of aerial parts of sweet potato, the at least one essential oil is included in a proportion of between 0.5% and 10%, for instance between 1% and 5%, by weight, with respect to the total weight of the polymeric matrix, in particular the PBSA matrix, and of the insect repellent active agent, and the aerial parts of sweet potato plant are included in a proportion of between 0.5% and 10%, for instance between 1% and 5%, by weight, with respect to the total weight of the polymeric matrix (in particular the PBSA matrix) and of the insect repellent active agent.

[0078] In some embodiments, the insect repellent active agent is a mixture of at least one essential oil and of aerial parts of sweet potato, and the mixture of at least one essential oil and of aerial parts of sweet potato is included in a proportion of between 0.5% and 10%, for example between 1% and 5%, by weight, with respect to the total weight of the polymeric matrix, in particular the PBSA matrix, and of the insect repellent active agent.

[0079] Without being limited to any one theory, the Inventors consider that the presence of the at least one essential oil makes it possible to improve the compatibility of the aerial parts of sweet potato plant with the polymeric matrix comprising PBSA, and thus to facilitate their incorporation in the matrix, in particular by extrusion.

[0080] Process for manufacturing the plastic product

[0081] Another object of the present invention is a process for manufacturing a plastic product comprising PBSA and an insect repellent active agent chosen from essential oils, aerial parts of sweet potato plant and any mixture thereof, comprising a step of melt extrusion of a mixture comprising the PBSA and the insect repellent active agent.

[0082] The term “melt” denotes conditions under which the polymeric matrix comprising PBSA is at least partially molten.

[0083] In some embodiments, the extrusion is a conventional extrusion. In other embodiments, the extrusion is blown film extrusion.

[0084] The extrusion is carried out under conditions, in particular temperature and duration conditions, suitable for the mixing of the insect repellent active agent and the polymeric matrix, preferably the PBSA polymeric matrix.

[0085] Preferably, the extrusion is carried out at a temperature at which the polymeric matrix is partially or completely molten, preferably completely molten. The use of a temperature at which the polymeric matrix is completely molten promotes the homogeneous distribution of the insect repellent active agent in the polymeric matrix.

[0086] The extrusion is preferably carried out at a temperature greater than or equal to 110°C, preferably at a temperature of between 130°C and 160°C.

[0087] The extrusion is preferably carried out at a temperature which limits the degradation of the insect repellent active agent.

[0088] In some embodiments, the mixing of the polymeric matrix with the insect repellent active agent is carried out before the extrusion. In other embodiments, the insect repellent active agent is added to the polymeric matrix during the extrusion. The addition during the extrusion makes it possible, in particular, to minimize the thermal stress to which the insect repellent active agent is subjected.

[0089] In some embodiments, the manufacturing process comprises a subsequent step of shaping the plastic product, which may be carried out by injection or by extrusion.

[0090] The term “approximately” or “about” placed before a numerical value denotes an interval of between plus and minus ten percent of the numerical value, preferably of between plus and minus five percent of the numerical value, for example of between plus and minus one percent of the numerical value. In the present invention, the term “comprise” and its variations are generally non-limiting, that is to say that the product may comprise other elements in addition to those indicated. In some embodiments, the term “comprise” may be interpreted more limitingly and mean “consist essentially of, or even “consist o .

[0091] A better understanding of the invention will be obtained in the light of the examples below, which should be considered as illustrative and nonlimiting of the scope of the invention.

[0092] EXAMPLES

[0093] Example 1: Insect-repellent effect of a PBSA film comprising a ground material of leaves of sweet potato plant

[0094] Preparation o f the film

[0095] The PBSA films were prepared as follows. PBSA granules were dried at 60°C overnight. The films were prepared using an extruder with a capacity of 15g, DSM microextruder model (Midi 2000 Heerlen, NL), with co-rotating screws (ratio of the length to the diameter L / D of 18). The mixtures were treated at 160°C for 3 minutes at a rotational speed of 100 revolutions / min (rpm). A 200-micron flat die was used.

[0096] Experimental site

[0097] The repulsion tests were carried out in a climate-controlled chamber with temperature set points of 20°C (± 2) and with a relative humidity (RH) of 65% (± 5). The lighting, composed of Philips cool white LED tubes and of Fluora Osram fluorescent tubes, observed a photoperiod of 16h:8h (D:N).

[0098] Aphids

[0099] Aphids are a major crop pest. The pea aphid Acyrthosiphon pisum is a species found in market gardening on numerous cultivated Fabaceae plants and which is a widely studied model in research due to its biological cycle characteristic of the majority of aphids and its optimal size for experimentation. The A. pisum aphids deposited in the device on day 0 of the tests are N1 nymphs, all wingless, born from the rearing on broad beans of winged adult aphids, all synchronized, in a climate-controlled chamber.

[0100] Treatment

[0101] The aphids were confronted for 24 h with biopolymer films which are potentially repellent by olfaction and then by contact. For this, samples of the films were placed near AP3 artificial medium for the nutrition of the pea aphids which reproduces the amino acid composition of the latter. The aphids deposited at a distance from the medium + film complex had to choose which direction to take between the repellent film and the control film by olfaction then to bypass or come into contact with the films in order to reach the nutritive medium and to feed on it.

[0102] Experimental device

[0103] The tests of choice were carried out on bars pierced with 6 chambers. 2 tubes are sealed on either side of these chambers with, at their end, AP3 medium coupled with a 30 x 5 mm strip of control film on one side and repellent film on the other side. Figure 1 shows a photo of the device used. 6 aphids were deposited in each chamber and then the bar was placed in a black box in order to avoid a bias with light. 3 repetitions per film were carried out, corresponding to 3 bars.

[0104] Measurements and statistical tests

[0105] The number of aphids fixed to the media or at less than 1 cm was counted on each side of the bars. The difference between the portion of aphids fixed to the control film and the portion fixed to the repellent film was analysed statistically with a Chi22 by 2 proportion comparison test with a significance threshold of 5% (0.05). The statistical analysis was first all carried out between the repetitions of each test in order to ensure their homogeneity and then between all the repellent films. Finally, a repulsion index (RI) was calculated in order to assign a final degree of repulsion to each tested film. The positive and negative values respectively indicate a repellent and attractive effect.

[0106] RI = [(Control No. - Repellent No. ) / Total No.] x 100, wherein: Repellent No. = number of aphids fixed to the medium coupled with the repellent film

[0107] Control No. = number of aphids fixed to the medium coupled with the control film

[0108] Total No. = total number of aphids fixed.

[0109] Repulsion indices o f the films

[0110] The repulsion indices were calculated for films containing different amounts of ground material of sweet potato leaves (1% by weight and 3% by weight). They were also calculated for a comparative PBSA film devoid of ground material of sweet potato leaves (0% by weight) and for a PBSA film comprising pure DiCQ (3,5-dicaffeoylquinic acid) in an amount equivalent to 10% by weight of ground material of sweet potato leaves, in a proportion of 5.9 mg / g of sweet potato leaves. The thickness of the film containing DiCQ is 230 micrometres ± 10 micrometres.

[0111] The results obtained and the repulsion indices of the films are described in detail in Table 1 below. The statistical indices is determined by a Chi2statistical test (P > 0.05) and the letters are assigned according to the significant differences. Table 1

[0112] The repulsion indices of the films comprising 1% and 3% by weight of ground material of leaves of sweet potato plant are 37% and 52% respectively, which demonstrates a very good repellent effect of the films. By way of comparison, the repulsion indices of the film containing DiCQ alone is only

[0113] 23%.

[0114] Example 2: Comparison of the thermal properties of DiCQ and of the leaves of sweet potatoes before and after introduction in the films

[0115] Figure 2 presents the comparative thermogravimetric analysis curves of DiCQ and of the ground material of leaves of sweet potatoes. This analysis demonstrates that DiCQ degrades at a lower temperature than the sweet potato leaves. Thus, at a temperature of 130°C, the weight loss of the

[0116] DiCQ is 5.5%, in comparison with 2.7% for the leaves of sweet potatoes. Then, at 180°C, 8.2% of losses for the DiCQ, compared with 4.5% for the leaves of sweet potatoes.

[0117] Figures 3 and 4 present the comparative thermogravimetric analysis curves of the PBSA films comprising, respectively, 10% by weight of sweet potato leaves and an amount of pure DiCQ equivalent to 10% by weight of sweet potato leaves. Although both thermograms are similar, a slight advanced degradation may be noted for the film containing the sweet potato leaves, which is not observed for the film containing pure DiCQ. This suggests that the film supposed to contain pure DiCQ does not contain or contains very little DiCQ active agent since, in the contrary case, a degradation should be observed at temperatures close to that of the degradation observed for the film containing sweet potato leaves. Thus, this suggests that the pure DiCQ introduced into the PBSA film has been partially degraded during the extrusion to a greater extent than when it was introduced by means of the sweet potato leaves. The extrusion temperature was 160°C.

[0118] Example 3: Thermal and mechanical properties of a film comprising leaves of sweet potato plant according to the invention

[0119] The thermal and mechanical properties of a PBSA film containing different amounts (5% and 10% by weight) of leaves of sweet potato plant were measured and compared with those of a PBSA film. The results are presented in Tables 2 and 3 below.

[0120] Table 2

[0121] Despite the observation of a slight decrease in the Young's modulus and in the elongation at break (for a content of 10%), it may be considered that the incorporation of up to 10% of leaves of sweet potato plant does not significantly affect the mechanical properties of the PBSA film.

[0122] Table 3

[0123] The incorporation of from 5% to 10% by weight of leaves of sweet potatoes does not influence the thermal properties of the PBSA film, whether in terms of the glass transition temperature, the melting point or indeed the degree of crystallinity.

[0124] Example 4: Manufacture of PBSA films containing essential oils

[0125] Materials and methods

[0126] The PBSA FD92PB BioPBS®, was purchased in the form of granules from Mitsubishi Chemical Europe GmbH. The ratio of the butylene succinate units to the butylene adipate units in the commercial -grade PBSA, such as that used in the present study, is approximately (PBS)o.75-(PBA)o.25.

[0127] The essential oils were provided by VosHuiles (Nevers, France) and result from organic or conventional industrial harvestings across the world. Preparation of PBSA / essential oil mixtures

[0128] PBSA granules charged with each essential oil at 1%, 2%, 3%, 4% and 5% by weight were prepared by direct incorporation in the melt polymer matrix using a co-rotating twin-screw extruder with 18 heating zones (L / D = 68, D = 18 mm, models ZSE 18 HPe, Leistritz Extrusionstechnik GmbH, Nuremberg, Germany). The parameters of the extrusion were determined via preliminary tests as making possible the best compromise between a homogeneous molten mixture and a minimum thermal stress for the essential oils, in particular with a starting temperature of 120°C ± 10°C. The screw speed was set at 300 rpm and the temperature varied from 35°C to 130°C within the extruder. Zone 1 was maintained at 35°C. Zones 2 to 7 were maintained at 130°C. Zones 8 and 9 were maintained at 120°C. Zones 10 to 18 were maintained at 115°C. The PBSA was introduced in zone 1 and the essential oil in zone 10.

[0129] The PBSA was dried in an oven at 60°C overnight and then introduced in zone 1 at a feed rate of 2 kg / h using a DSR28-20 measure device (Kubota Brabender Technologic GmbH, Duisburg, Germany) equipped with a single screw, reference 2019, and with a tube, reference 260. The essential oils were injected in zone 10 with a Gilson 305 piston pump (Middleton, WI, USA) equipped with a 25SC head. The essential oils were introduced in a distant zone in order to limit their residence time (estimated at 1 to 2 minutes).

[0130] The filament obtained in zone 18 with a 3-mm single-hole outlet was cooled in water and shaped into granules with a SGS 25-E4 granulator (Maag, Oberglatt, Switzerland). Finally, each mixture, produced in 1 or 2 kg, was dried overnight in an oven at 60°C and stored in heat-sealed metal bags.

[0131] Injection-moulded samples

[0132] Injection -moulded samples were manufactured from granules for the characterization of the PBSA / essential oil mixtures at the minimum and maximum concentrations, that is to say 1% and 5% by weight. The granules of each mixture were injected into a Battenfeld Unilog B2 / 350 Plus injectionmoulding device (Battenfeld GmbH, Meinerzhagen, Germany) with a 22 mm screw and a L / D ratio = 16. The device was regulated with an injection pressure of 120 MPa and a temperature of 120°C and 25°C, in the barrel and in the mould respectively. Standard tensile bars (ISO 527-2, type 1BA) with a width of 5 ± 0.5 mm in the reference zone and with a thickness of 2 ± 0.2 mm were devised in order to examine the tensile properties of the mixtures.

[0133] Films

[0134] The films were prepared with granules of each mixture using a Collin Teach-Line E20T single-screw extruder (Maiten-beth, Germany) (L / D = 25, D = 20 mm), at a screw speed of 60 rev / min at 120°C, connected to a Collin Teach-Line BL50T film blowing line with a Collin BL-D 30x0.8 T blown die. The wire feed speed was adjusted in order to produce films with a thickness of 80 ± 10 pm, corresponding to those used in plasticulture for covering tunnels or greenhouses.

[0135] The films obtained are thick, smooth, transparent, flexible, crack-free and bubble-free, which is suitable for use as covering films on crops.

[0136] Example 5: Stability of essential oils in the PBSA

[0137] Pure essential oils and granules of PBSA and of mixture of PBSA / essential oil at 1% and 5% by weight, were analysed by thermogravimetric analysis with a Q550 Thermogravimetric Analyser (TA Instruments, Wakefield, MA, USA). Samples of 6.0 ± 1.0 mg were heated from 30°C to 600°C at 10°C / min under a 60 mL / min nitrogen stream.

[0138] The thermograms obtained (Figure 5) demonstrate a low thermal stability of pure essential oils and a high thermal resistance of PBSA.

[0139] The thermograms of the PBSA / essential oil mixtures show a constant and sudden weight loss which suggests a homogeneous dispersion of the essential oils within the polymeric matrix at different doses. At a dosage of 1% by weight, the thermograms obtained are similar to those of PBSA, which demonstrates an improvement in the stability of the essential oils by virtue of their incorporation in the PBSA.

[0140] Thus, the PBSA / essential oil mixtures have a good thermal stability in the processing temperature range.

[0141] Chemical stability studies have also demonstrated that, during the manufacture of the film, the volatile chemical compounds present in the essential oils were successfully included in the PBSA matrix with a fairly good stability.

[0142] Example 6: Properties of PBSA films comprising an essential oil according to the invention

[0143] Thermal properties

[0144] In order to evaluate the effect of the essential oils on the properties of the PBSA as a function of the temperature, PBSA films and mixtures of PBSA / essential oil at 1% and 5% by weight were analysed by DSC (Differential Scanning Calorimetry) using a Q23 calorimeter (TA Instruments, New Castle, DE, USA). Samples of 4.0 ± 1.0 mg were stabilized under a nitrogen stream of 50 mL / min at -70°C, then heated at 10°C / min up to 150°C and maintained at this temperature for 2 min in order to erase the preceding traces. Subsequently, the samples were cooled to -70°C at 10°C / min, maintained at this temperature for 2 min and finally heated to 150°C at 10°C / min.

[0145] The following parameters were measured or estimated from the thermograms obtained: glass transition temperature Tg, melting point Tm, crystallization temperature Tc and percentage of crystallinity Xc.

[0146] Thermal properties of the PB SA were not substantially modified by the addition of the essential oils. The Tg values of the PBSA / essential oil mixtures showed a slight decrease from -47°C to -52°C. The Tm, Tc and Xc values and the crystalline distribution of the PBSA / essential oil mixtures were comparable to those obtained for pure PBSA, except for the 5% by weight Chinese cinnamon essential oil, which demonstrated a decrease of 10°C in the Tc and a modification of the crystalline distribution.

[0147] It is possible that the incorporation of the essential oils has led to a slight plasticization of the PBSA, with decrease in the Tg (and in the Tc in the case of the Chinese cinnamon essential oil).

[0148] Mechanical properties

[0149] Standard tensile bars of PBSA and of mixture of PBSA / essential oil at 1% and 5% by weight for each essential oil were subjected to uniaxial tensile tests using an Instron 4301 device (Norwood, MA, USA) equipped with an optical extensometer and with a 30 kN load cell. The initial distance between the jaws was 60 mm. Each sample was marked with 2 points at 20 mm from each other in the reduced cross section for their recognition by the extensometer. The tests were carried out at 22 ± 1°C and 50 ± 5% relative humidity, with a bridge head speed of 50 mm / min. 5 samples were tested for each mixture, and the mean values and standard deviations of the Young's moduli, of yield strength and of elongation at break were obtained by the Intron’s Bluehill Universal software.

[0150] As expected, the PBSA exhibited a ductile behaviour with a mean Young's modulus of 290 MPa and a yield strength of 17 MPa. The elongation at break is approximately 160%.

[0151] The mechanical properties of the mixtures of PBSA / essential oil at 1% by weight were not substantially different from those of pure PBSA, even if the elongation at break of the PBSA / Chinese cinnamon essential oil mixture was slightly improved (180%).

[0152] At 5% by weight, the 4 essential oils tested had a significant effect on the mechanical properties of the PBSA, with a decrease in the Young's modulus (250 MPa) and in the yield strength (14 to 16 MPa), and an increase in the elongation at break (200% to 270%). The effect was particularly significant for the Chinese cinnamon essential oil, with a mean increase in the elongation at break of 75% versus 25% for the other essential oils, with respect to pure PBSA.

[0153] Insect-repellent properties

[0154] The repellent activity was tested with pea aphids Acyrthosiphon pisum Harris raised on young Vicia faba LI Aquadulce’ plants. The aphids used for the test were wingless nymphs (Nl) of one day which are synchronized starting from wingless adults. A choice test was first carried out between a PBSA film and filter paper to confirm the absence of attractive or repellent nature of PBSA with regard to aphids. The repellent activity of the PBSA / essential oil films was subsequently tested for each essential oil at doses of 1%, 2%, 3%, 4% and 5% by weight.

[0155] The tests were carried out in darkness for 24 h. The nymphs were placed at the centre of a tube (8.33 cm3) sealed on both sides with a complete artificial nutritional diet coupled to a strip (0.5 x 3 cm) of PBSA film (control) and of PBSA / essential oil film (treatment). The aphids had to choose one side by olfaction and to pass under the film strip before settling on the artificial nutritional diet. On the following day, the number of aphids was counted on each side of the tube. The test was repeated 18 times with 5 aphids per tube, for a total of 90 aphids.

[0156] The repulsion of the films is shown in the graphs of Figure 6. The percentage of aphids on the control side was much greater than 50% in all cases, which confirms the strong repulsion of the films at all doses and for all the essential oils.

[0157] This additionally confirms that the essential oils were incorporated in the PBSA film without substantial degradation during the manufacturing process.

[0158] Biodegradation

[0159] The biodegradation of pure PBSA film and PBSA films comprising 1% or 5% by weight of an essential oil (basil, mint, peppermint or Chinese cinnamon) was studied as a function of time, over a period of 12 weeks, under soil burial conditions at room temperature.

[0160] The biodegradation of each film was measured at weeks 0, 2, 4, 6, 8 10 and 12. The biodegradation corresponds to the weight percentage of the remaining film.

[0161] Figure 7 shows the biodegradation of each film as a function of time. In each case, the essential oil present in a PBSA film made it possible to significantly accelerate the biodegradation of the film compared to the pure PBSA film. In particular, Chinese cinnamon essential oil at 5% by weight made it possible to significantly increase the biodegradation of the film, since only 1% by weight of the film remains after 6 weeks. Degradation

[0162] The number averaged molar mass ( / „), weight averaged molar mass (Mw), and dispersity of the molar mass distribution ( v / A / n) of pure PBSA film and PBSA films comprising 1% or 5% by weight of an essential oil were measured before and after one year of storage. The results are shown in Table 4 below.

[0163] In Table 4, “PBSA / XXXi” and “PBSA / XXXs” mean that the sample is a PBSA film comprising respectively 1% by weight or 5% by weight of the XXX essential oil. The essential oils are denoted as follow: BAS = basil; SPE = mint; PEP = peppermint and CIN = Chinese cinnamon.

[0164] Table 4

[0165] A comparison between original and aged films showed a general decrease in molar mass for all films, due to the interaction between essential oil molecules and the PBSA matrix over the year, leading to chain scission. This effect was most pronounced with Chinese cinnamon essential oil, particularly at 5 wt. %. The decrease in molar mass has the advantage of facilitating the degradation of the film and / or the biodegradation when it is buried in soil.

[0166] However, this decrease is less pronounced in films containing the other essential oils (at both 1% and 5% by weight) compared to the pure PBSA film. This suggests that these essential oils may slow down PBSA degradation, helping to maintain the properties of the films for a longer period. This effect could be attributed to the enhanced water barrier properties of PBSA / essential oil films, which protect PBSA from hydrolysis. It is therefore possible to adapt and / or optimize the required degradation time of a PBSA film by selecting the appropriate essential oils.

[0167] Example 7: Optimisation of the amount of leaves of sweet potato plant into a PBSA film comprising an essential oil

[0168] The insect-repellent property of a PBSAfilm comprising 1% by weight of cinnamon essential oil and 10% by weight of ground leaves of sweet potato plant was determined. It was compared to the insectrepellent property of an equivalent film comprising 4% by weight of ground leaves of sweet potato plant (instead of 10% by weight) and of a control film (i.e. devoid of essential oil and of ground leaves of sweet potato).

[0169] For the film comprising 10% by weight of ground leaves of sweet potato, 33% of pea aphids Acyrthosiphon pisum were on the side of the treated film (i.e. comprising cinnamon essential oil and sweet potato leaves) and 67% were on the side of the control film. For the film comprising 4% by weight of ground leaves of sweet potato, only 21% of pea aphids Acyrthosiphon pisum were on the side of the treated film and 79% were on the side of the control film.

[0170] This example demonstrates that a film comprising 4% by weight of ground leaves of sweet potato plant exhibits a better insect-repellent activity than a film comprising 10% by weight of ground leaves of sweet potato plant.

[0171] The insect-repellent activity was also determined for different PBSA films, each comprising 4% by weight of ground leaves of sweet potato plant and 1% by weight of either basil essential oil, mint essential oil or peppermint essential oil: for the film comprising basil essential oil: 26% of pea aphids Acyrthosiphon pisum were on the side of the treated film and 74% were on the side of the control film, for the film comprising mint essential oil: 20.8% of pea aphids Acyrthosiphon pisum were on the side of the treated film and 79.2% were on the side of the control film, and for the film comprising peppermint essential oil: 20% of pea aphids Acyrthosiphon pisum were on the side of the treated film and 80% were on the side of the control film.

[0172] Thus, a PBSA film comprising 1% by weight of an essential oil and 4% by weight of ground leaves of sweet potato plant exhibits a strong insect-repellent activity. The presence of ground leaves of sweet potato does not interfere with the repulsion activity of the essential oil.

[0173] Example 8: Thermal and mechanical properties of the films according to the invention

[0174] Thermal properties

[0175] The thermal properties of different PBSA films according to the invention were analysed by DSC and compared with those of a pure PBSA film.

[0176] The tested PBSA films contained 4% by weight of ground leaves of sweet potato plant (denoted SP4), eventually with 1% by weight of either cinnamon essential oil (CAi), basil essential oil (BASi), mint essential oil (SPEi) or peppermint essential oil (PEPi).

[0177] The following parameters were measured: glass transition temperature (Tg), melting point (Tm), crystallization temperature (Tc) and percentage of crystallinity (Xc). The results are presented in Table 5 below. Table 5

[0178] All tested films had a Tg similar to that of the pure PBSA film (contrary to the PBSA films comprising an essential oil only, as shown in Example 6 above): this demonstrated that the presence of ground leaves of sweet potato in a PBSA film comprising an essential oil prevents PBSA plasticization.

[0179] Despite a slight decrease in the Tc and Xc, the incorporation of a mixture of 4% by weight of ground leaves of sweet potato plant and 1% by weight of an essential oil does not significantly affect the thermal properties of the PBSA film.

[0180] Mechanical properties

[0181] The mechanical properties of different PBSA films were determined according to ISO 527-3 at room temperature on Instron 6025 / 5800R (Instron Limited, High Wycombe, UK). The test was conducted at a cross-head speed of 50 mm / min and utilized a load cell with a range of 100 N. The dumbbellshaped specimens, which corresponded to the ISO 527-3 / 5 type - half size with L(total) of 60 mm, W(middle part) of 3 mm, L(middle part) of 16.5 mm and W(ends) of 12.5 mm, were obtained by cutting from films. A minimum of five specimens were used in the test.

[0182] The tested PBSA films contained 4% by weight of ground leaves of sweet potato (SP4) and / or 1% by weight of either cinnamon essential oil (CAi), basil essential oil (BASi), mint essential oil (SPEi) or peppermint essential oil (PEPi).

[0183] The results are presented in Table 6 below.

[0184] Table 6

[0185] These results showed that the presence of ground leaves of sweet potato decreases the Young’s modulus of the PBSA film from 350 MPa to 155 MPa. The addition of cinnamon or mint essential oil into a PBSA film comprising ground leaves of sweet potato makes it possible to slightly increases the Young’s modulus. The mixture of ground leaves of sweet potato and an essential oil results in a PBSA film with improved mechanical properties, in terms of Young’s modulus, compared to a PBSA film comprising ground leaves of sweet potato only.

[0186] They also showed that the presence an essential oil only decreases or maintains at a similar level the elongation at break of the PBSA film. However, ground leaves of sweet potato significantly increase the elongation at break of the PBSA film from 250% to higher than 400%. This high elongation at break is maintained for a mixture of ground leaves of sweet potato and essential oil. The mixture of ground leaves of sweet potato and essential oil results in a PBSA film with improved mechanical properties, in terms of elongation at break, compared to a PBSA film comprising an essential oil only.

[0187] Example 9: Evolution of the insect-repellent property of a PBSA film comprising a mixture of an essential oil and ground leaves of sweet potato plant

[0188] This example aims at determining the insect-repellent property of different PBSA films over time. Four of the tested films contained 4% by weight of ground leaves of sweet potato (SP4) and 1% by weight of either cinnamon essential oil (CAi), basil essential oil (BASi), mint essential oil (SPEi) or peppermint essential oil (PEPi). One of the tested film contained 1% by weight of cinnamon essential oil only.

[0189] The insect-repellent activity was measured twice (Test 1 and Test 2) for each film, at intervals of either 90 or 55 days (i.e. Test 1 was for original films while Test 2 was for aged films). It was measured by determining the percentage of pea aphids Acyrthosiphon pisum present on the side of the treated film (%treated) and those present on the side of the control film devoid of essential oil and / or sweet potato leaves (%control).

[0190] A binomial test (Control vs Treated), comparing %control with %treated, was carried out for each film and for both Test 1 and Test 2 measurements: if P-value is lower than 0.05, then the insectrepellent property of the film is significant.

[0191] Finally, a Chi2test (Test 1 vs Test 2), measuring the difference in the insect-repellent activity between original films (Test 1) and aged films (Test 2), was carried out for each film: if P-value is lower than 0.05, then the difference is significant.

[0192] Thes results are shown in Table 7 below.

[0193] Table 7

[0194] The insect-repellent activities of the PBSA / CAi and PBSA / CA1 / SP4 films were measured at 90 days intervals whereas the insect-repellent activities of the PBSA / BAS1 / SP4, PBSA / SPE1 / SP4, and PBSA / PEP1 / SP4 films were measured at 55 days intervals.

[0195] All tested films exhibited a strong insect-repellent activity at the Test 1 measurements (all the P- values are lower than 0.05).

[0196] However, it was observed a significant decrease in the repellent activity between Test 1 and Test 2 measurements for the PBSA / CAi film only (P-value (Testi vsTest2) = 0.01): the aged PBSA / CAi film is significantly less repellent than the original PBSA / CAi film.

[0197] On the contrary, all the films comprising a mixture of an essential oil and ground leaves of sweet potato do not lose their effectiveness in terms of insect-repellent activity (P-value(Testi vs Test2)>0.05).

[0198] Thus, this example demonstrates that the presence of ground leaves of sweet potato plant makes it possible to attenuate the decrease in the repellent activity of the essential oil and / or delay the release of the essential oil. A PBSA film comprising both an essential oil and ground leaves of sweet potato maintains its strong insect-repellent property for at least 55 days or 90 days.

Claims

CLAIMS1. Use of a plastic product comprising polybutylene succinate adipate (PBSA) and an insect repellent active agent chosen from essential oils, aerial parts of sweet potato plant and any mixture thereof, for repelling pests, such as insects.

2. Use according to Claim 1, wherein the plastic product is chosen from the group consisting of antiinsect nets, covers for agricultural fields, plastic covers, storage bags and gardening pots.

3. Use according to Claim 1 or 2, wherein the pests are insects of the Aphidoidea family, such as aphids.

4. Use according to any one of Claims 1 to 3, wherein the essential oil is chosen from the group consisting of basil essential oil, mint essential oil, peppermint essential oil, cinnamon essential oil, such as Chinese cinnamon essential oil, French marigold essential oil, rosemary essential oil, thyme essential oil, oregano essential oil and any mixture thereof.

5. Use according to any one of Claims 1 to 4, wherein the plastic product has a thickness of less than 100 micrometres.

6. Use according to any one of Claims 1 to 5, wherein the aerial parts of sweet potato are a ground material of leaves of the sweet potato plants.

7. Use according to any one of Claims 1 to 6, wherein the plastic product comprises at least one other polymer in addition to PBSA, preferably PHB, PHBV or any mixture thereof.

8. Use according to any one of Claims 1 to 7, wherein the amount of the insect repellent active agent is from 0.5% to 5% by weight, with respect to the total weight of the PBSA + insect repellent active agent mixture.

9. Use according to any one of Claims 1 to 8, wherein the insect repellent active agent is a mixture of at least one essential oil and aerial parts of sweet potato plant.

10. Use according to Claim 9, wherein each of the at least one essential oil and aerial parts of sweet potato plant is included in a proportion of between 1% and 5% by weight, with respect to the total weight of PBSA and the insect repellent active agent mixture, preferably the at least one essential oil is included in a proportion of 1% by weight and the aerial parts of sweet potato plant are included in a proportion of 4% by weight, with respect to the total weight of PBSA and the insect repellent active agent mixture.

11. Use according to Claim 9 or 10, wherein the at least one essential oil is cinnamon essential oil or mint essential oil.

12. Use according to any one of Claims 1 to 11, wherein the plastic product comprises a polymeric matrix comprising PBSA and the insect repellent active agent, the insect repellent active agent being distributed in the polymeric matrix comprising the PBSA.

13. Use according to any one of Claims 1 to 12, wherein the plastic product is manufactured by a melt technique, such as extrusion, in particular conventional extrusion or blown film extrusion.

14. Plastic product, in particular plastic film, comprising PBSA and an insect repellent active agent chosen from essential oils, aerial parts of sweet potato plant and any mixture thereof.

15. Process for manufacturing a plastic product comprising polybutylene succinate adipate (PBSA) and an insect repellent active agent chosen from essential oils, aerial parts of sweet potato plant and any mixture thereof, comprising a step of melt extrusion of a mixture comprising the polybutylene succinate adipate (PBSA) and the insect repellent active agent.

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