MXPA00008035A - Barrier preventing wood pest access to wooden structures - Google Patents

Abstract

A method and device are disclosed which prevent the intrusion of insects (termits, ants) into wood structures by using a barrier comprising a polymer (preferably a polyurethane) having incorporated therein a pesticide (pyrethroid or oganophosphate insecticide). The insecticidal agent may be incorporated into the polymer by itself or in association with a carrier (preferably carbon black or activated carbon) as a bound friable mix. The barrier is placed between the wood structure (e.g. a wall or windowsill) and a non-wood structural portion such as soil. In the disclosed method the barrier maintains a minimal effective level of insecticide for a predetermined period of time.

Description

BARRIER THAT AVOIDS THE ACCESS OF WOOD PESTS TO WOODEN STRUCTURES FIELD OF THE INVENTION The present invention relates to barriers to prevent wood pests (eg, termites and borers) from having access to wooden structures, for the long-term protection of wooden structures. More specifically, it refers to a composition and method that creates and maintains an exclusion zone for insect pests such as termites, ants and other borer insects. As used herein, the term "bioactive" means to stimulate an organism, usually in a negative way up to and including death for purposes of deterrence.

BACKGROUND OF THE INVENTION The wood that is in contact with concrete, such as in the construction of wood and wood buildings that is in contact with the ground, for example, fence posts, poles for electrical service, railway cross ties and wooden supports , can be structurally degraded by the action of termites, ants and other borer insects. Insecticides are available to protect wood from the action of these pests. In construction of wooden buildings, wood in contact with concrete can be structurally degraded by the action of one or more wood pests including, but not limited to, termites, ants and other borers. The present methods of prevention or retardation of the advance of the insects include fumigation, where the whole structure can be sealed and an insecticide applied therein. The disadvantages of this method include the ecological and human health aspects as well as the limited time until the fumigant is sufficiently reduced in concentration to allow the entry of the insect. Although insecticides are effective against the action of borer insects, insecticides must be applied repeatedly at intervals of a few days to a few months or a year to remain effective. If the insecticides are applied in sufficient quantity to be effective for a while, they have ecological aspects, for human health and can present unpleasant odors, leaching in the soil and volatility of the insecticide. In addition, even larger amounts of insecticides applied by themselves dissipate within a relatively short time and need to be reapplied. Another disadvantage of traditional application methods is that the concentration of the bioactive ingredients resulting from a single application of insecticide starts well above the minimum level necessary for effectiveness, but decreases rapidly and within a relatively short time falls below the level effective minimum necessary to maintain a barrier. To this end, in recent years some techniques have been developed for the controlled release of chemical substances such as insecticides. These methods employ polymer matrices and microcapsules to release the insecticide. Patent US 4,400,374 Cardarelli describes the use of polymer matrices generally made of polyethylene, polypropylene, ethylene vinyl acetate, polyamide, polystyrene, polyvinyl acetate or polyurethane to control the release of insecticides such as insecticides that are available commercially under the Dursban brand. The polymeric matrices described in US Pat. No. 4,400,374 incorporate a porosity agent and a porosity reducing agent that dissolves the matrix upon contact with soil moisture or an aqueous environment. Similarly, US Pat. No. 4,405,360 to Cardarelli refers to a polymeric release matrix which may be composed of polyamide, polyurethane, polyethylene, polypropylene, polystyrenes and other polymers. The controlled release mechanism works in combination with a porosigen to release a herbicide in a humid environment. A disadvantage of Cardarelli's methods is the need for sufficient moisture to dissolve the matrix. The periods of dryness, although they prolong the life of the matrix, they would cause a decrease in the concentration of the insecticide, thereby allowing access to insects. In addition, the longevity of the matrix is variable and depends on the moisture content. In addition, US Pat. No. 4,435,383 to Wysong teaches the use of a controlled release mechanism for insecticides including carbamates, organothiophosphates, organophosphates, perchlorinated organic substances and synthetic pyrethroids. The release mechanism consists of a hydrophobic barrier monomer, namely styrene and / or methylstyrene in combination with a monomer selected from one or more unsaturated mono- or dicarboxylic acids. Another reference, US Pat. No. 4,282,209 to Toc er describes a process for the preparation of insecticidal-polymer particles. The insecticide, methomil, is used to control insects that attack tobacco, cotton or agricultural crops. Methomyl is dissolved with polymers such as polyamides, urethanes and epoxies to provide prolonged residual insecticidal activity. A second Tocker patent, U.S. Patent 4,235,872, discloses the use of slow release insecticidal microcapsules having a methomyl core surrounded by a non-crosslinked, polychromatic, [sic] polyurea shell. In the arrangement described in this patent, methomil is used to protect vegetables, field crops and fruit crops. A sixth reference, U.S. Patent 4,198,441 to Young et al., Describes the use of insecticides such as Dursban in a controlled release matrix containing an organopolysiloxane, a hydrolysable silane and a hydrolysable organic titanium. In addition, U.S. Patent 4,160,335 to Young et al. , describes a way to disperse substances to control insects by applying strips to cellophane sheets. The substance to control insects that may include Dursban, is placed in a polymer as well. Another method is described in Australian Patent AU-B-82443/91. In this patent, two sheets of plastic extracted from feeder rolls are described. The upper face of the lower sheet and the lower face of the upper sheet are dragged past the respective coating rollers which apply a coating of pesticide (eg, permethrin) in a volatile solvent to the faces of the sheets. The coated faces of the sheets are brought together passing between compressor rolls. The coated and compressed sheets are left under the foundations of the construction, or are placed around the trees or plants to prevent the attack of termites. Disadvantages of this product and method include: (1) the breaking of a layer allows quick escape of the coating, and (2) the coating is not integrated into the sheets thereby allowing faster diffusion through the sheets and limiting the effective life. Coated granules have a pesticide absorbed onto a matrix like clay and then coated with crosslinked resins that help slow down the rate of release. The clay loses or releases the pesticide for a short time of at most a few weeks. Although the prior art describes the use of an insecticide incorporated in a polymeric matrix as controlled release agents, none of the references teaches the creation and maintenance of a fully effective exclusion zone that lasts a few years or more. It would be beneficial to create a zone to prevent any contact between the wooden structure and the insects capable of damaging such structures. A reliable exclusion zone is necessary to protect wooden structures for times substantially longer than one year. Therefore, in view of the foregoing, an objective of this invention is to provide an insecticide zone to protect wooden structures. Such an area consists of a barrier with little volatility, long-term and a short-term barrier, high volatility to protect the soil. Another objective of this invention is to maintain an exclusion zone for a relatively long time of approximately 10 to 20 years.

COMPENDIUM OF THE INVENTION The present invention is a barrier against wood pests having a half life that is effective during the life of the structure. The life time is achieved by joining the pesticide within the polymer matrix, substantially preventing by this means the release of the pesticide from the polymer. The bond can be obtained by mixing the pesticide with a carrier as a mixture of friable combined before placing the mixture of the friable combination into the polymer matrix. The barrier can be supplemented with additional layer (s) that include, but are not limited to, thin canvas, mesh, sheet and combinations thereof. The additional layer (s) may contain a second pesticide that is the same or different - as compared to the barrier pesticide. In addition, it is possible to allow the second pesticide to be released from the additional layer (s) to improve short-term protection. The barrier and / or the additional layer (s) are made with a polymer selected from the group consisting of thermoplastic polymers, thermosetting polymers, elastomeric polymers and copolymers thereof. By incorporating the insecticides into the polymers, the insecticides can be maintained or released at such a rate that they will continue to be effective as poisons or insect repellents capable of damaging wood structures for a long time while at the same time maintaining sufficient concentrations within the barrier to prevent the penetration of the insect through the barrier. In accordance with one aspect of this invention, there is provided a polymeric carrier system wherein the pesticide is attached to the carrier as a mixture of friable combination. The laminate with the mixture of the friable combination is then placed near a wooden structure to provide a barrier that does not penetrate the wood pests. An additional layer can provide the means for slow and relatively constant release of the volatile insecticide in order to create a barrier zone beyond the barrier itself in the soil around a wood structure. The polymers include thermoplastic polymers, thermosetting polymers, elastomeric polymers, as well as copolymers thereof, and the insecticide consist of the family of insecticides known as pyrethrins. In accordance with another aspect of this invention, an exclusion zone is created by placing an extrusion near the wooden structure to be protected. The extrusion has a polymeric release system capable of controlled release of the insecticide. The carrier system maintains a constant and effective concentration of the insecticide in the exclusion zone for long periods. According to another aspect of this invention, granulate containing a polymer and insecticide is provided to create and maintain an equilibrium concentration of the insecticide for ants, termites and other wood boring insects in an exclusion zone for the wood structure. The granulate is placed near a wooden structure to treat the soil in order to protect the wood structure from termites, ants and other borers. The granulate can be placed close to the structure by various means. In addition, the granulate can be embedded in a board or even included in a foam. In the preferred embodiments, the polymers include thermoplastic polymers, thermoset polymers, elastomeric polymers, - as well as copolymers thereof and the insecticide are pyrethrins. In accordance with another aspect of this invention, an exclusion zone is created by injecting a hot melt polymer blend. The controlled release device consists of one or more pyrethrins and the polymer is selected from the group consisting of thermoplastic polymer, elastomeric polymers and copolymers thereof. In accordance with another aspect of this invention, temperature-controlled controlled release devices are used to provide the exclusion zones. According to another aspect of this invention, the controlled release device is used to fumigate structures. You want to place a barrier or create an area to prevent any contact between the wooden structure and insects capable of damaging such structures. An exclusion zone is necessary to protect the wooden structures for a long time. In another aspect of the present invention, a high density polymer having a low volatility insecticide providing a slow release rate of the insecticide is combined with a low density (soft) polymer having a more volatile insecticide to provide a reliable exclusion zone ). Therefore, in view of the foregoing, an objective of this invention is to provide an insecticide barrier to protect wooden structures. Another objective of the present invention is to provide a barrier and an exclusion zone having a low barrier for long term volatility and a high volatility, short term barrier to protect the adjacent floor. Another objective of this invention is to maintain a barrier for a longer time or approximately 10 to 20 years. The present invention, together with the objects and advantages mentioned, will be better understood with reference to the following detailed description when read together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 illustrates a first embodiment of the invention, consisting of a polymeric coating bonded by spinning or spinning, and a physical melt-bonded mixture of the polymer and the insecticide, wherein the mixture of the polymer and the insecticide are bound in spots to the coating polymeric FIGURE 2 illustrates a second embodiment of the invention, consisting of a polymeric coating bonded by centrifugation, and a physical melt-bonded mixture of the polymer and the insecticide. Where the polymer mixture the insecticide are bonded in ribbons to the polymeric coating. FIGURE 3 illustrates a first way of using the embodiments of the invention shown in FIGURES 1 and 2 and the exclusion zone created by the release of the insecticide. FIGURE 4 illustrates a second way of using the first and second embodiments of the invention to create an exclusion zone. FIGURE 5 illustrates a third mode of using the embodiments of the invention shown in FIGURES 1 and 2 creating an exclusion zone. FIGURE 6 illustrates a third embodiment of the invention, in the form of a cylindrical extrusion. FIGURE 7 illustrates a fourth embodiment of the invention, in the form of a flat tape extrusion. FIGURE 8 illustrates a way to create an exclusion zone using the embodiment of the invention shown in FIGURE 6. FIGURE 9 illustrates a mode of using the embodiment of the invention shown in FIGURE 7 to create an area of exclusion. FIGURE 10 illustrates another embodiment of the invention in the form of granules, wherein the granules are being inserted into the soil near a wooden structure. FIGURE 11 illustrates a cross-sectional view of the granules placed on a surface. Figure 12 illustrates the application of the granules to a concrete structure using foam. FIGURE 13 illustrates a cross-sectional view of a concrete foundation after the foam has been applied. FIGURE 14 illustrates granules established on a board. FIGURE 15 illustrates a board containing granules applied to a concrete foundation. FIGURE 16 illustrates a hot melt injection. FIGURE 17 illustrates the separation of the injection with hot melt. FIGURE 18 illustrates a plug fumigating cement blocks. FIGURE 19 illustrates one way to apply plugs to fumigate cement blocks. FIGURE 20 shows a stratified apparatus of the present invention. FIGURE 21 shows the repellency of eastern subterranean termites. FIGURE 22 shows the repellency of the Formosan subterranean termites.

DETAILED DESCRIPTION It has been found that there is a significant reduction of insects capable of damaging wood structures when a barrier, alone or in combination with an insecticide exclusion zone, is maintained for a longer time in the soil surrounding the structures. An exclusion zone is an area that has a sufficient amount of chemical agent to deter wildlife. In the present invention, the chemical agent is an insecticide and the fauna are insects, especially borers, for example, termites and ants. In accordance with the present invention, the insecticide is maintained in a barrier and / or is released from a controlled release device consisting of a polymeric matrix system that will last at least 6 years.

A controlled release device refers to an apparatus that gives rise to a controlled and prolonged release of a bioactive chemical substance to its surface and from its surface to the surrounding medium, for example, the soil. The apparatus provides a method for controlled release of the chemical substance into the surrounding environment. The device releases insecticide at a high speed initially and a lower speed, constant later. This release profile ensures that the wooden object is protected in a relatively short time and thatAfter reaching the minimum effective level, only the amount of insecticide needed to replace the degraded insecticide will be released. This release profile decreases the potential environmental and health problems of the treatment and reduces the cost of treatment. The device's release speed depends only on the construction of the device and is independent of external elements such as water. The controlled release device provides a short and medium term solution by releasing the insecticide to the soil at a desired rate to create an area that has the "minimum effective level" of the insecticide necessary to prevent the entry of insects. As used in this specification and the appended claims, the term "effective minimum level" is defined as the concentration of insecticide needed in the area to prevent insects from entering the area, the specific concentration depends on the specific insect and the specific insecticide. . When placed next to a foundation or structural portion below the level, the exclusion zone is created on the ground near the apparatus. When it is placed between • a structural portion not of wood and a structural portion of bonded wood, the exclusion zone is created at the interface between the non-wood structural portion and the structural portion of bonded wood. The insecticides that are used in the preferred modalities must be insecticides authorized by the U. S. Enviromental Protection Agency (Office of Protection • 10 Environmental of the United States) to kill or repel termites, ants and other borer insects. The insecticide that is currently preferred for use in the present invention are pyrethrins, including tefluthrin, lambdacyhalotrin, cyfluthrin and deltamethrin. However, experts in the art will realize that it is also possible to use other effective insecticides such as isophenphos, fenvalerate, cypermethrin, permethrin and natural pyrethrin. These are available to various commercial sources such as Dow, Mobay, ICI, Velsicol and FMC, respectively.

Also contemplated within this invention is a combination of insecticides, or one or more insecticides in combination with other bioactive ingredients as fungicides. A first modality of controlled release of the The invention is illustrated in FIGURE 1, which utilizes a polymeric carrier apparatus for the controlled release of the insecticide in order to generate an exclusion zone. The U modality -consists of a polymer coating joined by centrifugation 20, and a mixture joined by physical melting of the polymer and the insecticide (shown in points 21 in FIGURES 1 and 3-5). The spin-linked polymeric coating 20 can be a woven or non-woven fabric or it can be a polymer sheet. The textiles can be obtained from different manufacturers such as Reemay, Exxon ^^ 10 Fibers and Phillips Fibers. Preferably, the textile is woven or non-woven polypropylene. The polymer in the melt-bonded mixture can contain any number of thermoplastic polymers, thermoset polymers, elastomeric polymers or copolymers thereof. The choice of polymers depends on the desired release rate, the compatibility of the polymer with the insecticide and the environmental conditions. By way of example and not to limit the scope of this invention, it is possible to use the following polymers: high density polyethylene, low density polyethylene, vinyl acetate, urethane, polyester, santoprene, silicone or neoprene. However, the preferred polymers are high density and low density polyethylene. Although it is possible to use insecticides before mentioned for best results, insecticides should ideally contain chlorpyrifos. The polymer and insecticide mixture can be placed on the polymeric coating bonded by centrifugation in certain areas. These areas must be separated to adequately maintain the amount of insecticide above the minimum effective level in an exclusion zone. The minimum effective level is the minimum amount of insecticide needed in an area to prevent the entry of insects. The zones 21 in FIGS. 1 and 3-5 are preferably approximately 0.5 to 1.5 centimeters in diameter, and approximately 0.5 to 1.5 centimeters in height. The size and shape of the points will depend on the user preference and can be designed for the work contemplated by the buyer. The points 21 can be configured in rows with the separation of the dots being preferably from approximately 1.5 to 4 centimeters from the adjacent points. Those skilled in the art will realize that it is also possible to use other configurations points depending on the specific application. The polymeric leaf that releases insecticide is placed near or around the wooden structure to create an exclusion zone by controlled release of the insecticide. A second controlled release mode of the invention also utilizes a polymeric carrier delivery system for the controlled release of the insecticide consisting of a spin-linked polymeric coating and a physical melt-bonded blend of the ^ _ .. polymer and insecticide. The polymeric coating 20 as in the first embodiment can be woven polypropylene or non-woven in which the physical melt-bonded mixture (shown as strips 22 in FIGURE 2) is attached. In the same way, the polymers and the insecticide described above with respect to the first embodiment can also be used in the manner described in this section.

The mixture of the polymer and the insecticide of the second embodiment can be otherwise placed on a spin-linked polymeric coating using extruder systems that provide strips, for example, as shown in FIG. 2. Strips or tapes 22 may be approximately 1 centimeter in height and approximately 5 to 15 centimeters apart. Optimally, the tapes should be placed approximately 10 ^ centimeters of separation. It is desirable that the tapes are configured in such arrangement to allow a concentration The insecticide constant in the exclusion zone after a first initial burst of the insecticide. After the tapes are applied to the polymer sheet, the sheet is placed on or near the wooden structure to be protected from insects. Binders and / or potting fillers may also be included in all embodiments of the invention. The inclusion of the binder and / or carrier loading material allows larger amounts of insecticide for a given release rate or allows a lower release rate for a given amount of the pesticide. The binder carrier is attached to the pesticide. Binders that can bind to the pesticide include carbon-based carriers, e.g., carbon black, activated carbon, and combinations thereof. It is considered that alumina, silicoaluminate, hydroxyapatite and combinations thereof can be comparable to carbon to bind bioactive chemicals. When using a carbon-based carrier, the first step is to ensure carbon dryness followed by mixing the insecticide in a liquid form with the carbon. Only enough carbon black (filler) is used to produce a friable mixture. The term "friable" means fluid particles that are practically anhydrous or non-sticky. Certain pesticides may have to be heated to obtain a liquid form. The liquid insecticides adhere or agglomerate to the extremely large surface area of the finely divided carbon black and the mixture is cooled for incorporation into the polymer. The polymers that can be used in a carbon application are polyethylene, polypropylene, copolymers or blends of polyethylene and polypropylene, polybutylene, epoxy polymers, polyamides, acrylate-styrene-acrylonitrile, aromatic or unsaturated polyesters, polyurethanes, silicones or any other polymers or suitable copolymers thereof. The mixture of carbon-insecticide in the first and second modalities (or only the insecticide, if carbon is not used). then it is mixed with the polymer, preferably polyurethane in the molten, powder or liquid state. Then this mixture is bonded to the polymeric coating. In the first and second embodiments of the invention, the polymer and insecticide are fused to the polymeric coating. Another way of attaching the polymer and insecticide mixture to the polymeric coating is "through injection molding", a well-known technique. In "injection molding", the molten material is injected from a heated nozzle through a porous continuous material and into a mold. The molten material flows through the continuous material under pressure and solidifies in the mold. Although the molten material is being injected, the porous continuous material allows air to escape, but also retains the melt under pressure until it cools. A different bonding method of mixing the polymer and insecticide to the polymeric coating is to place a molten mixture of the polymer and insecticide on the ^ polymeric coating joined by centrifugation. If the mixture is melted, it should be allowed to cool, cure and solidify. As used hereafter, "a molten mixture of the polymer and the insecticide" is proposed to indicate that the polymer is molten or is already in the liquid state. The insecticide can also be melted or contained in a slurry solution, depending on its melting point f 10. A "molten blend of polymer and insecticide" may also contain carbon or other additives that do not melt but flow with the molten polymer / insecticide mass. The first and second embodiments of the invention must provide sufficient release rates to maintain an effective insecticide concentration in the exclusion zone to kill or repel insects, but ^ speeds slow enough to maintain an effective concentration for a long time. In general, a preferred composition of the first and second embodiments of the invention contains from about 70 to 95 parts by weight of the carrier polymer, from about 0 to 15 parts by weight of carbon and from about 5 to 30 parts by weight of insecticide. The design considerations of the controlled release devices vary according to factors such as user preference and geographical conditions. The rate of steady state release of the polymeric delivery system of these two modes after the initial insecticide burst can be maintained for at least 6 years as a barrier to insects such as ants and termites. However, the equilibrium concentration of this modality can easily be adjusted to meet the specific needs of each user. Optionally, the embodiments shown in FIGS. 1-5 may contain a sheet impermeable to the pesticide (not shown) such as a metallized sheet. The metallized sheet or an extruded sheet of a polymer is laminated on one side of the spin-linked polymeric coating to direct the flow of the insecticide. Another embodiment of the present invention is a barrier of a sheet impervious to the pesticide wherein a mixture of the friable compound of the bioactive chemical or pesticide with a carbon carrier is placed inside a polymer and has practically no release of the bioactive chemical substance. Practically no release is defined as a release rate of less than 0.4 μg / cm / day, preferably less than 0.1 μg / cm / day, and more preferably less than 0.05 μg / cm / day. This modality comprises a release speed of 0.0 or below the limits • detectable. In this embodiment, the pests are deterred by "smelling" or "scraping" a polymeric surface and detecting the presence of the bioactive chemical harmful to the pests. The half-life of the barrier is much longer than a barrier with a higher release rate. In addition, a defect or tear in the polymer will be less likely to "leak" the bioactive chemical. Hence, two or more layers • 10 of this modality may be preferred to maintain a complete barrier. Multiple layers will allow a tear or hole in a layer but the pest will not pass a second or subsequent non-tearing layer. In addition it may be desirable to place a protective layer, for example, a thin canvas, on one or both sides of a barrier layer to prevent tearing. Once manufactured, the polymeric-carrier supply systems of the first and second embodiments are placed close to the structure to be protected from insects FIGURES 3-5 illustrate some applications of the dots or ribbons modalities of the invention. The configuration of FIGURE 1 is shown in FIGURES 3-5, but it will be understood that the configuration of FIGURE 2, or other configurations may work well. In FIGURE 3, the polymeric carrier supply system 1 is placed under and along a concrete foundation 23 of a wood structure 100 creating an exclusion zone 10 to protect the termite structure, ants and other borer insects. In FIGURE 4, the polymeric carrier supply system 2 is placed under a structural element 24, such as a porch, patio, sidewalk or under a foundation on one side of the wooden structure 101 to provide an exclusion zone 10. In FIGURE 5, the polymeric carrier supply system 3 is placed on and on the sides of the concrete foundation 23 of a wood structure 102, but under the wood portion 25 of the structure to create an exclusion zone. Another embodiment of the invention is illustrated in FIGS. 6 and 7. This embodiment pertains to extrusions, such as extruded flexible cylinders 26 and flexible, extruded flat belts 27 which are respectively shown in FIGS. 6 and 7. It is possible to use a wide variety of polymers that can be classified into four broad subgroups. The groups include thermoplastic polymers, thermoset polymers, elastomeric polymers and copolymers of the three aforementioned groups. For example, some polymers that can be used for the four groups are: high density polyethylene, low density polyethylene, EVA, vinyl acetate, urethane, polyester, santoprene, silicone, neoprene and polyisoprene. The preferred insecticide is chlorpyrifos, although it is possible to use the insecticides described above. A filler material can also be added. The cylinders preferably have a size ranging from about 5 to 15 millimeters in diameter, but more preferably, about 10 millimeters in diameter for the optimum continuous supply of the insecticide in the exclusion zone. Flat belts should preferably have a thickness of about 1 to 6 millimeters and a width of about 5 to 15 millimeters. However, it should be noted that cylinders and flat ribbons can be designed to meet the different conditions encountered by the user. In general to maintain an equilibrium concentration of the pesticide in the exclusion zone for a prolonged time, the composition of this embodiment of the invention should contain from about 70 to about 95 parts by weight of polymer, from about 0 to 30 parts by weight of carbon and from about 5 to about 30 parts by weight of the pesticide. However, the composition of the extrusion can be designed to the specific needs of the user. It is estimated that the exclusion zone can be maintained for at least 6 years for one cylinder and the same time for flat belts. The extrusions can be placed in a variety of positions to create the exclusion zones. FIGURE 8 illustrates one way to use the extrusion shown in FIGURE 6. One or more flexible cylinders 26 are placed between the concrete foundation 23 'and the wood portion 25' of the structure. The flexible cylinders 26 release the insecticide at a controlled rate to create an exclusion zone. An advantage of this configuration is that it is possible to place the flexible cylinders 26 under a structure that has already been constructed. Similarly, in a mode not shown, the flexible cylinders can be placed in a vertical position on the ground opposite the horizontal position. As will be recognized by those skilled in the art, the extrusions may have other convenient shapes and be placed in any suitable position depending on the specific contemplated use. FIGURE 9 illustrates a way of using the extrusion of the flexible flat belt shown in FIGURE 7. One or more flexible flat ribbons 27 create an exclusion zone by being placed between or along the concrete foundation 23"and the 25"wood portion of the structure. The flexible flat ribbons 27 can also be placed vertically along a wall in a manner not illustrated in the drawings. Again, any convenient placement of the flat ribbons is considered within the scope of the invention. The controlled release of the insecticide can also to be conveniently obtained using granulates as used in the embodiments shown in the FIGURES -13. The granulate 13 contains polymer, insecticide and, preferably, also includes a filler material. It is possible to use different polymers in this modality.

^ W 10 These may consist of polymers of the four subgroups consisting of thermoplastic polymers, thermoset polymers, elastomeric polymers and copolymers thereof. The choice of polymer from these four subgroups will depend on the design considerations with the The preferred polymer is high density polyethylene or low density polyethylene. In turn, the preferable insecticide consists of tefluthrin, but it is also possible to use the following insecticides: isofenphos, fenvalerate, cypermethrin, permethrin and other pyrethrins. For For optimal results, a carrier such as carbon can also be incorporated into the mixture. The granulate 31 releases the insecticide at a controlled rate for a prolonged time to establish an exclusion zone. The composition for this granulate The necessary for the maintenance of a zone in the soil is from about 70 to 95 parts by weight of polymer, from about 0 to about 30 parts by weight of carbon black and from about 5 to about 30 parts by weight of insecticide. Finally, the compositions of the granulate will depend on the user's preference. The granulate can be of any convenient size depending on the proposed use, such as 1 to 25 millimeters in diameter (or width and thickness, if rectangular) by 2 to 20 centimeters more in length. In addition, to adapt to the specific needs of the user, the size of the granulate and the concentrations of the insecticide can be easily adjusted. However, it is possible to maintain an exclusion zone for at least 6 years. In addition, the granulate 31 has the advantage that it can be conveniently placed anywhere. The granulate of this embodiment of the invention is shown in FIGURE 10. The granulate 31 is inserted near a wooden structure 25. The granulate as illustrated in FIGURE 10 can be placed under a cement foundation 23 '"or can be be placed directly under the wooden structure (not illustrated) to allow the creation of an area 10 surrounding the wooden structure 25 '"to exclude insects capable of damaging these structures. FIGURE 11 shows a cross-sectional view of the granulate 31 inserted on a surface 40. -j The granulate is easily applied for a wide variety of uses. FIGURE 12 illustrates the sprayed granulate 50 on a surface of concrete structure 40. The FIGURE 15 illustrates the treatment of a surface by placing granulate 33 on the preformed boards 300. The granulates 32 are placed on the surface 40 such as the floor or concrete through a foam 41 as ^ P 10 is illustrated in FIGURE 13. The granulate is first incorporated into a foam in a manner known in the art. The foam 41 containing the fine granulate is then roela 50 as illustrated on the surface 41 by means of a motorized sprinkler 70 in FIGURE 12 to provide a protective coating for the surface. The granulate 32 then releases the insecticide to create a protective barrier in the soil in order to protect the wood from the harmful insects. For best results, the foam 50 is composed of polyurethane, it is also possible to use silicone, polyester or polyvinyl acetate. The granulate 32 can vary in size depending on the thickness of the foam and the desired insecticide concentration in the exclusion zone. The thickness of the foam to be applied to a surface can vary according to the user's preference. The exclusion zone can be maintained for at least 6 years. In addition to being used as a carrier for the insecticide, the foam also heals the cement and acts as an insulator. - A preformed board with embedded granulate 33 can also be used as an embodiment of this invention as illustrated in FIGURE 14. This board 30 can be made of any type of material that can adequately contain the granulate 33. Preferably, the Board is composed of styrene foam that is registered as a Dow brand. The board can be applied in a variety of ways and can also function as an insulating device. One mode of application is illustrated in FIGURE 15, where the board 300 with the granulate 33 is placed on a concrete surface 42. The embedded granulate is regularly separated with the separation being specified by the amount of insecticide considered. In another embodiment as shown in FIGS. 16 and 17, the controlled release device consists of the polymer matrix and the insecticide can be applied through a hot melt. This modality is designed to meet the needs of structures already placed. As already stated, the polymer matrix can consist of any of the four polymer groups mentioned above. In the same way, it is possible to use any of the aforementioned insecticides. It is preferable to use high density or low density polyethylene with a pyrethrin. Although designed for the user, the concentrations of the different substances in the hot melt application should range from about 70 to about 95 [sic] for the polymer, from about 5 to about 30 for the insecticide and from about 0 to about 30 for the load / carrier material for • 10 optimal results. FIGURE 16 shows the hot melt 50 being injected by a syringe 400 into the soil near a concrete foundation 43. The concrete structure 43 supports a wood structure 250. FIGURE 17 shows the separation between the hot melt 50 that has already been injected into the ground. In another embodiment, FIGURES 18 and 19 illustrate the use • of the insecticide to fumigate a 500 structure. When injecting and placing the controlled release device on or near of a structure that can be fumigated, the insecticide released from the controlled release device can be vaporized thereby fumigating the structure. FIGURE 18 illustrates the use of plugs 34 for fumigating an elaborate structure 500 of building blocks 502. Likewise, the FIGURE 19 illustrates one way of applying the controlled release device using a drill 800 to drill a hole 700 in a cement slab 900. Once inserted, the plug can fumigate the structure.

CURRENTLY PREFERRED MODALITY The currently preferred embodiment of the apparatus of the present invention, as shown in FIGURE 20, combines a first polymer 200 of medium or high density polymer having an insecticide with low vapor pressure with a second polymer 202 of low density having a more volatile insecticide, vis [sic] of higher vapor pressure. High, medium and low density are terms well known in the polymer art and refer to the degree of crosslinking within a polymer. The high vapor pressure is defined as the vapor pressure in excess of about 1 millipascal and preferably in the range from about 10 millipascales to about 100 millipascales. The low vapor pressure is defined as less than 1 millipascal and is preferably in the range from about 0.05 millipascales to about 0.5 millipascales. The first polymer 200 preferably has a thickness in the range from about 1/32 to 1/8 inches. The low vapor pressure insecticide is preferably permethrin, or lambdacialotrin. The preferred material of the first polymer 200 is selected from polyurethane, high density polyethylene and polypropylene. The second polymer 202 is placed ^ adjacent to and, preferably attached to the first polymer 200. It is preferred that the first polymer 200 be impermeable to the water and radon. Therefore, the first polymer 200 is preferably a sheet that can be a film or spin-bonded. According to the present invention, the first polymer 200 can be in two sub-parts with a sub-part 204 a permeable medium or high density polymer ^ containing a low vapor pressure insecticide and another sub-part 206 an impermeable layer without insecticide. The waterproof layer has an advantage for handling to avoid or reduce the exposure or contact of the installer with the bioactive chemical. The waterproof layer can be, for example, Mylar, saran or Saranax. The second polymer 202 is a low density polymer, preferably an ethylene vinyl acetate, a low density polyethylene QP or mixture thereof. The most volatile insecticide or high vapor pressure placed inside the The second polymer is preferably a synthetic pyrethroid, for example, tefluthrin. The second polymer 202 may be in the form of granules as already described, and the first and second polymers deployed with the first polymer under a plate stationary on a foundation and the second polymer dispersed in the soil adjacent to the foundation. More preferably, the second polymer 202 is in the form of an open mesh, woven or non-woven as shown. The holes in the mesh can be the gap from the contact but not sealed to about 1 to 4 square inches and flanges 208 having a transverse width from about 1 thousand to about 1/8 inch. As a mesh a thin canvas can be used that can be made of polyethylene, polypropylene or polyester. With a sheet of the first polymer 200 and an open mesh of the second polymer 202, the apparatus of the combination of the first and second polymers 200, 202 is preferably placed under level. The sheet of the first polymer 200 is placed adjacent to the open mesh of the second polymer 202 with the sheet of the first polymer 200 in contact or near a foundation 43 and between the foundation and the open mesh of the second polymer 202. The material of the mesh It can absorb the bioactive chemical and contribute to the deposit of the bioactive material. During operation, the first polymer 200 maintains a physical / chemical barrier against the entry of insects. However, due to the slow release of the first polymer 200, very little insecticide is released which would be available to create an exclusion zone within approximately the first year after installation.

In addition, it is impossible to install a barrier without defects due to penetrations, for example, electrical or plumbing, and due to punctures or tears during construction. Accordingly, the second polymer 202 is exhausted to create exclusion zones within a few days of the installation thereby preventing insect access through the imperfections of the first polymer 200. The first polymer 200 therefore has three functions : insect barrier, vapor / moisture barrier and ^ 10 barrier against radon. The first polymer 200 is designed to last at least 10 years and preferably up to and in excess of 20 years. The second polymer 202 is designed to last at least 5 years and preferably up to about 10 years. At the moment that the second Polymer 202 is depleted and no longer effective against insects, the first polymer 200 will have developed an insecticide concentration and released sufficient to maintain the exclusion zone. The following 'examples are provided as explanation. As such, these examples should not be seen as limiting the scope of the invention as defined by the attached clauses.

EXAMPLE 1 Experiments were performed to determine the release rate of chlorpyrifos. The loading rates for the insecticide were 5% by weight or 10% by weight, depending on the polymer. Release rates were determined for all devices at 50 ° C. The polymers evaluated included low melt polyethylene, polyurethane, two epoxies, silicone rubber and a low melting polyethylene high in waxes to reduce the thermal decomposition of chlorpyrifos. The studies indicated that excessive thermal decomposition of chloropyrifos occurred at temperatures in excess of approximately 240 ° C; thus, the selection of the polymer was limited to formulations that do not require excessive thermal processing. Table 1 provides a summary of the results of these studies. In general, the compatibility of the polymer with chlorpyrifos did not seem to present a problem with the charge rates used. There was some loss of physical integrity of the polyurethane polymer used, however, the other polymeric systems showed no visible degradation at 50 ° C. The release rates ranged from 10 μg / cm / day, for silicone rubber to 0.3 μg. / cm / da [sic] for epoxy B. When using the data provided in Table 1, an estimated product longevity can be approximated Assuming a device weight of 0.5, with 10% load, then 50 mg of chlorpyrifos is For a polymer system with an area of 4 cm 2, and a release rate of 1 μg / cm2 / day [sic], there is enough insecticide to last 30 years at high temperature. that a variety of insecticide products is possible.

Table 1. Polymer formulations and release rates for candidate systems using chlorpyrifos.

Polymer Class Content of Speed of chlorpyrifos (%) release (μg / cm / day, [sic]) Polyurethane 5 2.1 ± 1.4"Epoxy A 5 <0.1 Silicone 5 10.3 ± 3.5 Urethane 10 1.0 ± 0.3 Epoxy B 10 0.3 + 0.1 PE + wax 10 1.9 ± 0.3 Releasing speeds performed at 50 ° C. Materials showed excessive temperature cracking elevated EXAMPLE 2 Studies were also carried out with similar polymeric systems as in Example 1, but with 80% pure pyrethrin. The release rates at 40 ° C are given in Table 2.

Table 2. Polymer formulations and release rates for candidate systems using Piretrin? Polymer Class Content of Pyrethrin Speed I (%) release (μg / cm / day [sic]) Epoxy A 10 0.5 ± 0.2 Silicone 10 21.2 ± 5.4 Urethane 10 15.7 ± 7.1 Epoxy B 10 0.2 ± 0.1 release rates performed at 40 ° C.

Release rates were higher for urethane and silicone and lower for epoxies. Substantial variability in release rates was found and it will be necessary to evaluate suitable binders. From the data in Table 2, it is possible to perform simple calculations to determine the possible life of the insecticide systems. As stated in Example 1, there are many variables that can modify the half-life of an exclusion zone.EXAMPLE 3 Controlled release devices were made and tested to obtain their release rates. All thermoplastic polymers were formulated with 10% pesticide, 3 or 7% carbon black to absorb the liquid pesticide and 83 to 87% by weight polymer and injection molded into thin sheets about 1/8 inch thick. Specifically, the devices made from thermoplastic polymers and deltamethrin and lambdacialotrin contained 3% carbon black. The devices made from the remaining pesticides and the thermoplastic polymers contained 7% carbon black. Devices made from urethane S-113 (a thermosetting polymer) were prepared from a polymer blend containing 60% S-113, 40% castor oil and 5% TIPA catalyst by weight. The polymer mixture contained 90% of the total weight of the device. The pesticide, deltamethrin, consisted of the remaining 10% of the device. No carbon black was used in this device. The polymer / pesticide mixture was poured into a 1/8 inch thick sheet and heated to about 60 ° C for about 40 to 60 minutes to cure the cast sheet. Then one-inch squares of these thin sheets that were injection molded or cast were cut and the frames were tested for release rates. The following release rates were obtained: EXAMPLE 4 An experiment was performed to determine the effect of • the concentration of lambda-cyhalothrin (pyrethroid) and the insecticide / polymer combination on the release rate of the insecticide from the polymer. The data is summarized in Table 4.

Table 4. Release rate for polymer / pyrethroid concentration combinations. • 10 EXAMPLE 5 An experiment was conducted to determine the efficacy of the exclusion zone against termites. Two were selected species of termites for testing. Termite of underground of the East because it is the most common, and underground termite of Formosa because it is the most aggressive. The test cells were assembled with glass containers. Wood chips were placed in the bottom of the containers. The insecticide-impregnated polymer was placed on the pieces of wood in a manner so that there was no path or hole from above the impregnated polymer towards the pieces of wood. A probe without nutrient was placed on the impregnated polymer. The surface of the probe was zero data and the impregnated polymer was mounted at a distance of 5 centimeters below the surface of the probe. The termites were placed on the surface of the probe and their advance through the probe to the impregnated polymer was observed every day. The impregnated polymer combinations are shown in Table 5a Table 5a. Release rate for 10% by weight of pyrethroid Controls without pyrethroid were also used in a polymer barrier. The results are shown in FIGURE 21 and FIGUR 22. In all controls, the termites passed through the polymer and had access to the pieces of wood. The access speed through ethylvinyl acetate was slower than for polyethylene. In all the impregnated polymers there was no penetration. Because the Formosan subterranean termites are so aggressive, they came closer to the impregnated polymer than less aggressive eastern termites. In fact, the polyethylene with permethrin suffered mandibular marks from the termites of Formosa, but no holes or penetration. After approximately 12-14 days, a termite from Formosa was dissuaded by the release of the insecticide and backed away from the impregnated polymer.

EXAMPLE 6 An experiment was performed to demonstrate the effect of a binder carrier on the rate of release. The chemicals were tefluthrin and lambdacialotrin in an amount of 5% by weight, the binder carrier was carbon black in amounts of 0% by weight and 10% by weight with the polyethylene high density difference (MA 778-000). Release rates were measured at six weeks after manufacture, where the samples were cleaned weekly to eliminate surface accumulation of the active chemical released. The results are shown in Table 6.

Table 6 - Release rates for 0% by weight and 10% by weight of carbon black.

From the aforementioned description, those skilled in the art will easily find out the essential characteristics of this invention and without departing from the spirit and scope of it can make changes and modifications of the invention to adapt it to different uses and conditions. It is proposed that the scope of the invention be defined by the following clauses that include all equivalents that are proposed to define this invention.

Claims (31)

1. A barrier to preventing a wood pest from having access to a wood structure consists of: (a) a contained pesticide. (b) a polymer matrix; wherein (c) the pesticide is in an amount that is bound within the polymer, the amount sufficient to prevent the wood pest from breaking the barrier.

2. The barrier as recited in claim 1, wherein the pesticide is not substantially released from the barrier.

3. The barrier as mentioned in any of the preceding claims, wherein the pesticide is combined with a carrier as a friable combined mixture that is added to the polymer. The barrier as mentioned in any of the preceding claims, wherein the pesticide is a low volatility pesticide and the polymer has a high or medium density. 5. The barrier as mentioned in any of the preceding claims, further contains another pesticide that is a pesticide of higher volatility within another polymer that is a low density polymer. The barrier as recited in claim 4, wherein the low volatility insecticide is selected from the group consisting of lambdacialotrin, permethrin and combinations thereof. The barrier as recited in claim 4, wherein the polymer having a high or medium density is selected from the group consisting of: polyurethane, high density polyethylene, and combinations thereof. 8. The barrier as mentioned in any of the preceding claims, wherein the amount of the pesticide is at least 1% by weight. 9. The barrier as recited in claim 8, wherein the amount of the pesticide is at least 5% by weight. The barrier as mentioned in claim 3, wherein the carrier is selected from the group consisting of carbon black, activated carbon and combinations thereof. The barrier as mentioned in any of the preceding claims, wherein the pesticide is selected from the group consisting of isophenphos, fenvalerate, cypermethrin, permethrin, pyrethrin, and combinations thereof. 12. A method for manufacturing a barrier to prevent a wood pest from having access to a wood structure consists of the steps of: (a) selecting an amount of a pesticide, and. (b) linking the amount of the pesticide within the polymer matrix; wherein • (c) the amount sufficient to prevent the wood pest from breaking the barrier. The method as recited in claim 12, wherein the pesticide is not substantially released from the polymer. 1

4. The method as mentioned in any of the • 10 claims 12 to 13, wherein the agglutination consists of the steps of: mixing the pesticide with a carrier as a friable combined mixture; and adding the friable combined mixture into the polymer. 1

5. The method as recited in any of claims 12 to 14, wherein the pesticide is a low volatility pesticide and the polymer has a high or medium density. 1

6. The method as recited in any of claims 12 to 15, further comprising the step of: mixing another pesticide that is a high volatility pesticide within another polymer that is a low density polymer. 1

7. The method as recited in claim 13, wherein the low volatility insecticide is selected from the group consisting of: lambdacialotrin, permethrin and combinations thereof. The method as recited in claim 15, wherein the polymer having a high or medium density is selected from the group consisting of: polyurethane, high density polyethylene, and combinations thereof. 19. The method as recited in any of claims 12 to 18, wherein the amount of the pesticide is at least 1% by weight. 20. The method as mentioned in claim 19, wherein the amount of the pesticide is at least 5% by weight. The method as recited in claim 14, wherein the carrier is selected from the group consisting of carbon black, activated carbon and combinations thereof. 22. The method as recited in any of claims 12 to 21, wherein the insecticide is selected from the group consisting of: isophenphos, fenvalerate, cypermethrin, permethrin, pyrethrin and combinations thereof. 23. A method to create a barrier for the entry of crawling or ground-dwelling insects to provide long-term protection of a soil area or structure from the intrusion of these insects, the method comprising the steps of: (a) ) placing a controlled release barrier at the entry points to the area or structure, the barrier having an external surface and consisting of a polymeric matrix and a pesticide within this matrix; (b) allow the pesticide to be released to the external surface of the controlled release barrier and accumulate on the surface, the release rate of the pesticide being at least 10 μg / cm / day, the speed being sufficient to repel or kill insects that come in contact with the surface of the barrier to protect the area or structure from the inclusion of crawling insects or housed in the ground. The method as recited in claim 23, wherein the crawling or ground-dwelling insects are selected from the group of insects, vipers and combinations thereof [sic]. The method as recited in any of claims 23 to 24, wherein the polymer-matrix is selected from the group consisting of silicas, EVA, urethanes, polyurethanes, acrylonitrile, butane ene, acrylic rubber, isoprene and styrene rubber. -vinyl. 26. The method as recited in any of claims 23 to 25, wherein the polymer matrix further includes a carrier for controlling the rate of release. The method as recited in claim 26, wherein the carrier is selected from the group consisting of carbon black, activated carbon, amorphous silica and combinations thereof. The method as recited in any of claims 23 to 27, wherein the controlled release device is in the form of a sheet, or granulate. 29. The method as recited in claim 26, wherein the concentration of the carrier is from about 2 to about 7% by total weight of the carrier. 30. The method as recited in any of claims 23 to 29, wherein the concentration of the pesticide is from about 2 to about 15% of the total weight of the barrier. The method as recited in any of claims 23 to 30, wherein the pesticide is selected from the group consisting of deltamethrin, cypermethrin, lambdacialotrin, tefluthrin, permethrin and combinations thereof.