WO2014068575A1

WO2014068575A1 - Agricultural barrier for crop cultivation

Info

Publication number: WO2014068575A1
Application number: PCT/IL2013/050901
Authority: WO
Inventors: Meirav FLEICHER; Yafit MOYAL; Menachem DINAR
Original assignee: Tosaf Compounds Ltd.
Priority date: 2012-11-05
Filing date: 2013-11-04
Publication date: 2014-05-08
Also published as: IL222861A; EP2914091A1

Abstract

The present disclosure provides an agricultural barrier comprising a polymeric material having a plurality of openings, said polymeric material comprising: (a) at least one thermoplastic polymer, and (b) non-doped nanoparticles comprising one or more metal oxides. In one embodiment, the metal oxide is titanium oxide. In some further embodiments, the nanoparicles consist of titanium oxide.The agricultural barrier may be used for constructing agricultural housings for cultivation of a variety of crops. The present disclosure also concerns a method for manufacturing the barrier, the method comprising mixing a combination of at least one thermoplastic polymer and the nanoparticles, under condition which cause the combination to form into a melt; and processing said melt into a polymeric material having a plurality of openings.

Description

AGRICULTURAL BARRIER FOR CROP CULTIVATION

TECHNOLOGICAL FIELD

The present disclosure relates to the field of agriculture, specifically agricultural barriers designed to protect crops and plants.

BACKGROUND

Integrated pest and disease management relies on an array of tactics, including synthetic pesticides and physical controls. Scientific evidence show that chemically active pesticides are residually present on food, in water supplies, in the soil, and that these chemicals may interfere with animal growth and development, and together with the public demand for reduced-risk pesticides, efforts are made in the development of economically sustainable and environmentally safe physical controls.

Physical controls can be classified as passive (e.g., trenches, fences, tunnels, organic mulch, particle films, inert dusts, and oils), active (e.g., mechanical, polishing, pneumatic, impact, and thermal), and miscellaneous (e.g., cold storage, heated air, flaming, hot- water immersion).

US Patent No. 4,826,729 describes an insect pest-repelling film or sheet having a reflective spectrum in the ultraviolet region of a wavelength of less than 0.4 μπι, a visible light reflectance of a wavelength of 0.5μπι and a visible light transmission of not less than 40%. The film is described to be useful as a cover of houses and tunnels or mulching of ground for crop culture or as a repellent for various insect pests in agriculture, forestry, and gardening.

US Patent No. 6,796,083 describes a barrier for protecting plants and crops from insects comprising a screen that reflects ultraviolet light toward the insects such that they are repelled from the screen. Also shown is an enclosure and a method for protecting plants and crops from insects including the reflecting screen. International Patent Application Publication No. WO09/080548 describes a UV absorbing polymer composition comprising effective amounts of, inter alia, nanoparticulate oxide selected from oxides of the groups 4 and 12, and a UV light stabilizing substance comprising a N-oxygen-substituted sterically hindered amine (NOR-HALS). The present polymer composition may be used as a UV absorber in agricultural films or packaging films.

SUMMARY OF DISCLOSURE

In accordance with one aspect, the present disclosure provides an agricultural barrier comprising a polymeric material having a plurality of openings, said polymeric material comprising: (a) at least one thermoplastic polymer, and (b) non-doped metal oxide nanoparticles. In some embodiments, the non-doped nanoparticles are nanoparticles consisting of one or more metal oxides.

In accordance with another aspect, the present disclosure provides an agricultural housing wherein at least a portion thereof is formed from an agricultural barrier according to the present disclosure.

In accordance with yet another aspect, there is provided a method of producing an agricultural barrier as disclosed herein, the method comprising mixing a combination of at least one thermoplastic polymer and the metal oxide nanoparticles under condition which cause the combination to form into a melt; and processing said melt into a polymeric material having a plurality of openings.

In accordance with a further aspect, the present disclosure provides an agricultural method comprising cultivating crop within a housing wherein at least a portion of said housing comprises the agricultural barrier as disclosed herein.

BRIEF DESCRIPTION OF THE FIGURES

In order to understand the disclosure and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying figures, in which: Figure 1 is a schematic illustration of an agricultural tunnel (10) according to an embodiment of the invention having side sections (14) formed from an agricultural barrier.

Figure 2 is an image of a series of crates having walls formed from an agricultural barrier according to the present disclosure.

DETAILED DESCRIPTION OF DISCLOSURE

The present disclosure is based on the finding that incorporating titanium dioxide (Ti(¾) nanoparticles within a polymeric grid-like barriers, provides, on the one hand, sufficient transparency of the polymeric barrier suitable for transmission of light therethrough, and on the other hand, provides the barrier with insect repelling capabilities.

More specifically, the present disclosure is based on the finding that cultivating crop within a small scaled crates that simulated cultivation in an agricultural tunnel, with at least the side sections of the crates were constructed from the polymeric grid like barriers containing the Ti(¾ nanoparticles significantly increased the yield of the crop as compared to a reference physical barrier (e.g. tunnel or crate without the Ti(¾ containing nanoparticles).

Thus, in accordance with one aspect, the present disclosure provides an agricultural barrier comprising a polymeric material having a plurality of openings, said polymeric material comprising: (a) at least one thermoplastic polymer, and (b) nanoparticles of one or more metal oxides. In one embodiment, the nanoparticles are non-doped nanoparticles. In a particular embodiment, the nanoparticles consist only of metal oxide.

In some embodiments, the polymeric material comprises at least one hindered amine light stabilizer (HALS).

In the context of the present disclosure, the term "polymeric material" is used herein to denote a combination of at least two components selected from polymers and the metal oxide nanoparticles. The polymeric material according to the present disclosure is characterized by having a dual effect. On one hand, the polymeric material is essentially transparent and thus enables transmission of visible light in the range of 400nm to 700 nm sufficient for crop cultivation. The wavelength region of 400nm to 700nm relates in the art to photosynthesis active radiation (PAR). On the other hand, the inventors have surprisingly found that the disclosed polymeric material also reflects visible light in the range of 400nm to 700 nm to an extent that is sufficient to repel insects. Thus, the inventors of the present disclosure have developed a barrier that balances between the extent of visible light transmitted through the barrier and the extent of visible light that is reflected which resulted in a non-obvious increase in crop production protected by the developed barrier.

The polymeric material of the invention is characterized by the presence of spaced apart plurality of openings. In the context of the present disclosure the term "plurality of openings" encompass any grid like or grid containing structure, preferably in the form of a perforated sheet, a net, a web, etc. When referring to a plurality of opening it is to be clear that the polymeric matrix is not a film, or any sealed (non- perforated) laminated sheet.

The plurality of openings do not necessarily have to be equally spaced apart, although in some embodiments, due to the method of manufacturing the barrier, the plurality of openings are essentially equally spaced apart as is in industrial nets or webs. The openings are not limited to any size or shape.

In some embodiments, the openings may be uniform throughout the polymeric material barrier, in terms of shape and size. In some embodiments, the openings may be a combination of different sizes and/or different shapes. This may be dictated by the method of its production.

In some embodiments, the plurality of openings are defined by having between about 10 to 70 openings per inch length. In some other embodiments, there are 15 to 60 openings per inch length. In some further embodiments, there are 30 to 50 openings per inch length.

One component of the polymeric material is at least one thermoplastic polymer. The thermoplastic polymer may include a single type of polymer (e.g. in terms of chemical formula of the repeating unit and average length of the polymer), or a combination of polymers, e.g. co-polymers where the repeating unit may not always be same. The polymeric barrier may be employed at various thicknesses, depending on the type of agricultural structure they are to be used in and the manner of manufacturing.

In one embodiment, the polymeric material is formed from filaments, e.g. monofilaments, interconnected to form a net like structure or any other pattern providing the structure with the desired plurality of opening. The filaments may be produced by extrusion, as known in the art and also discussed below.

In some other embodiments, polymeric materials with a plurality of openings, in accordance with the present disclosure may be produces from tapes cut out of stretched films. Specifically, initially, films are produced, these films are then stretched in one or more direction and tapes are cut from the stretched film to be used as filaments.

In some embodiments, the polymeric material comprises monofilaments with a thickness in the range of between 0.5 to 500 micron, at times the monofilaments have a thickness in the range of between 100 to 400 micron, or even in the range of 200 to 300 micron.

Without being limited thereto, the polymeric material including the plurality of openings may be produced by weaving or other methods to form a woven, intertwined, braided, non-woven and the like materials.

The polymers to be used are preferably selected from "thermoplastic polymers" also known by the term "thermoplasf

As appreciated by those versed in the art, a "thermoplastic polymer" is a polymer that changes its physical state upon heating or cooling. In other words, when heated, it softens and fluidizes (melts) albeit, once cooled, the thermoplastic polymer solidifies. The thermoplastic polymer may be re-melted and re-molded more than once (as opposed to thermosetting).

The "thermoplastic polymer" may be any one of homopolymers, copolymers, terpolymers such as for example, block, graft, random and alternating copolymers, further including their derivatives, combinations and blends thereof.

In some embodiments, the thermoplastic polymer is an organic polymer, namely, a carbon hydrogen based polymer, In the context of some embodiments of the present disclosure, the at least one thermoplastic polymer is selected from the group consisting polyolefin and copolymers, polycarbonate or polyvinyl chloride.

As used herein, the term polyolefin encompasses any polymer comprising an alkene as a monomeric unit. The polymers in the present disclosure can contain as a monomeric unit a monoolefin (having one double bond per monomer), a diolefin (having two double bonds per monomer) etc. This monomeric unit may form a homopolymer or may be combined with another monomeric unit to form a copolymer.

Non limiting examples of polyolefin are polyethylene (PE), polypropylene (PP) , polybutylene (BP), poly-4-methylpent-l-ene, polyvinylcyclohexane, polyisoprene polybutadiene or polymethylpentene (PMP).

According to the some embodiments, the polyethylene is a high density polyethylene (HDPE), high density and high molecular weight polyethylene (HDPE- HMW, between 700 and 1,800 monomer units per molecule) or high density and ultrahigh molecular weight polyethylene (HDPE-UHMW, 100,000 to 250,000 monomer units per molecule).

In some embodiments, the thermoplastic polymer is a mixture of two or more polymers. In some embodiments, the thermoplastic polymer is a mixture of polypropylene with polyethylene.

As noted above, the thermoplastic may also encompass co-polymers. In some embodiments, the thermoplastic polymer comprises copolymers of olefins or copolymers with non-olefin monomers, such as vinyl monomers. Non-limiting examples of co-polymers include, ethylene/propylene copolymers, propylene/but-l-ene copolymers, propylene/isobutylene copolymers, ethylene/but-l-ene copolymers, ethylene/hexene copolymers, ethylene/methylpentene copolymers, ethylene/heptene copolymers, ethylene/octene copolymers, ethylene/vinylcyclohexane copolymers, ethylene/cycloolefin copolymers (e.g. ethylene/norbornene like COC), ethylene/ 1 -olefins copolymers; propylene/butadiene copolymers, isobutylene/isoprene copolymers, ethylene/vinylcyclohexene copolymers, ethylene/alkyl acrylate copolymers, ethylene/alkyl methacrylate copolymers, ethylene/vinyl acetate copolymers or ethylene/acrylic acid copolymers and their salts (ionomers) as well as terpolymers of ethylene with propylene and a diene such as hexadiene, dicyclopentadiene or ethylidene-norbornene; and mixtures of such copolymers with one another and with polymers for example polypropylene/ethylene -propylene copolymers, LDPE/ethylene- vinyl acetate copolymers (EVA), LDPE/ethylene- acrylic acid copolymers (EAA), polyethylene butyl acrylate (EBA) LLDPE/EVA, LLDPE/EAA and alternating or random polyalkylene/carbon monoxide copolymers and mixtures thereof with other polymers, for example polyamides.

In some embodiments, the thermoplastic polymer is a polycarbonate, namely, Polymers containing carbonate groups (-0-(C=0)-0-). Some non-limiting example of polycarbonates include, without being limited thereto, poly(methyl methacrylate).

In accordance with some other embodiments, the thermoplastic polymer is a polyvinyl chloride.

In accordance with the above, the polymer may be one or more polymers selected from the group consisting of polyethylene, polypropylene, polycarbonate, poly(ethylene-co-tetrafluoroethylene), polyvinyl chloride, polyethylene vinyl acetate, polyethylene butyl acrylate, polyethylene methyl acrylate (EMA).

As noted above, the polymeric material comprises non-doped nanoparticles and preferably nanoparticles consisting only of one or more metal oxides.

The term "nanoparticle" is used herein to denote discrete nanoscopic particles, with at least one of their dimensions being in the nanometric range, typically in the range of about lnm to 500 nm, in one cross-sectional dimension or diameter, at times within the range of 15nm-150nm. In the context of the present disclosure, the term "nanoparticles" is used to denote that the metal oxide described herein is present in a form of nanoparticles or is encompassed within nanoparticles.

In some embodiments, and as noted above, the nanoparticles according to the present disclosure are non-doped nanoparticles. In this context, the nanoparticles are not doped or combined with a doping element such as elements from groups 13, 14 and 17 of the periodic table, such as Indium, Gallium and/or Aluminum.

In some embodiments, the nanoparticles are essentially transparent. According to the present invention, the term "metal oxide" encompasses a variety of types of metals oxides, particularly from transition metals oxides.

In some embodiments, the metal oxide comprises a transition metal of block d of the Periodic Table. In accordance with this embodiment, the transition metal is a metal selected from Sc, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Y, Zr, Nb, Tc, Ru, Mo, Rh, W, Au, Pt, Pd, Ag, Mn, Co, Cd, Hf, Ta, Re, Os, Ir and Hg.

In some particular embodiments, the transition metal is titanium, zinc, zirconium, chromium, copper, cerium, hafnium, cadmium, mercury and iron.

Non-limiting examples of metal oxides are those selected from the group consisting of titanium dioxide (T1O₂), zinc oxide (ZnO), zirconium dioxide (Zr(¾), hafnium dioxide (Hf(¾), cadmium oxide (CdO), mercury oxide (HgO), chromium oxide (CrO) and copper oxide (CuO).

In some embodiments, the nanoparticles include a single type of metal oxide. In some other embodiments, the nanoparticles comprise a mixture of two or more metal oxide. Nonetheless, even when using two or more metal oxides, these nanoparticles are non-doped with any doping element. A doping element (also known in the art by the term "dopant" is to be understood as referring to a trace impurity element that is inserted into a substance (in very low concentrations) in order to alter the electrical properties or the optical properties of the substance. As such, when referring to non-doped nanoparticles it is to be understood as having no dopant (doping element).

In one preferred embodiments, the nanoparticles comprise Ί1Ο₂ nanoparticles. In some other embodiments, the nanoparticles consist of Τί(¾ nanoparticles.

As used herein, "one or more nanoparticles" refers to at least one type of nanoparticle and should not be construed as meaning a single particle per se. In other words, the term "one or more nanoparticles" denotes a population of nanoparticles which may include a single type of metal oxide or a combination of two or more types of metal oxides, namely oxides of more than one metal.

In some embodiments, the population may be classified by the nanoparticle size(s), size distribution, shape, chemical composition, spectroscopic property, topology, and/or other physical or chemical characteristics. The nanoparticles may be symmetrical or unsymmetrical, may be elongated having a rod-like shape, round (spherical), elliptical, pyramidal, disk-like, branch, network or any irregular shape. In some embodiments, the nanoparticles are selected from quantum dots (QD), nanocrystals, nanospheres, nanorods, nanowires, nanocubes, nanodiscs, branched nanoparticles, multipods such as tetrapod and others.

In some embodiments, the nanoparticles have an average size (size including length in one dimension or diameter) in the range of lnm to 200nm. In some other embodiments, the metal oxide nanoparticles have an average size in the range of lOnm to 150nm. In some further embodiments, the metal oxide nanoparticles have an average size in the range of 20nm.

It should be noted that the average size of the particles may be measured by any method known to a person skilled in the art for example by Dynamic Light Scattering (DLS) using a Malvern Zeta Nano Sizer.

In some embodiments, the combination of components forming the polymeric material may be defined by their percent weight with respect to the total weight of the polymeric material.

In this context and in accordance with some embodiments, the amount of the metal oxide nanoparticles is within the range of between 0.01% to 5% out of the total weight of the polymeric material.

In some other embodiments, the polymeric material comprises an amount of metal oxide nanoparticles within the range of between 0.05% to 2%.

In some further embodiments, the polymeric material comprises an amount of said metal oxide nanoparticles within the range of 0.1% to 1%

In yet some further embodiments, the polymeric material comprises an amount of said metal oxide nanoparticles within the range of about 0.5%

The polymeric material according to the invention may further comprise at least one hindered amine light stabilizer (HALS).

Hindered amines light stabilizers (HALS) are a class of organic UV light stabilizers. Generally, HALS are derivatives of 2,2,6,6-tetramethyl piperidine and are extremely efficient stabilizers against light-induced degradation of most polymers, therefore, widely used in the plastic industry.

HALS are recognized as degradation inhibitors, i.e. that inhibit degradation of the polymer by slowing down the photochemically initiated degradation reactions. HALS are sub-categorized to secondary HALS, tertiary HALS and NOR HALS. As known in the art, the difference between the groups is the atom attached to the active part of the molecule. In secondary HALS the active N (nitrogen) is connected to hydrogen and it has no chemical resistance; in tertiary HALS the active N is connected to a carbon atom (it can be just a methyl or a long chain), and these tertiary HALS have medium chemical resistance. However, in the NOR HALS the active N is connected to oxygen atom bound to a carbon atom, thereby giving the NOR HALS very high chemical resistance, albeit, on the other hand, the NOR HALS decomposes at a low temperature (about 225 °C) which is much lower than the decomposition temperatures of secondary or tertiary HALS. As such, the NOR HALS are only suitable for low density polyethylene (LDPE), linear low density polyethylene (LLDPE) or ethylene- vinyl acetate copolymers (EVA)/polyethylene butyl acrylate (EBA) (EVA/EBA). Therefore, in the context of the present invention NOR-HALS are excluded from the group of HALS suitable for preparing the novel agricultural barrier. Non limiting examples of HALS comprise the following Poly[[6-[(l,l,3,3-tetramethylbutyl)amino]-l,3,5-triazine- 2,4-diyl][(2,2,6,6-tetramemyl-4-piperidinyl)imino]-l,6-hexanediyl[(2,2,6,6-tetramethyl- 4-piperidinyl)imino]]), polymer with 4-hydroxy-2,2,6,6-tetramethyl-l-piperidine ethanol, l,3,5-Triazine-2, 4,6-triamine, N,N"-1,2- ethanediylbis[N-[3-[[4,6- bis [butyl( 1 , 2,2, 6, 6-pentamethyl- 4-piperidinyl)amino] -1,3, 5 -triazin-2- yl] amino] propyl]- Ν',Ν''-dibutyl- N',N"-bis( l,2,2,6,6-pentamethyl-4-piperidinyl), 1,6- Hexanediamine, N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-, Polymers with mo holine-2,4,6-trichloro-l,3,5-triazine, Poly [^-morpholino-s-triazine^^- diyl)[2,2,6,6-tetramethyl-4-piperidyl) imino]- hexamethylene[(2,2,6,6-tetramethyl-4- piperidyl) imino]], 1,6-Hexanediamine, N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)- polymer with 2,4,6-trichloro-l,3,5-triazine, reaction products with N-butyl-1- butanamine and N-butyl-2,2,6,6-tetramethyl-4 piperidinamine, alpha-Alkenes C20-24 polymers with maleic anhydride reaction products with 2,2,6,6-tetramethyl-4- piperidinamine, N,N'-Bis(2,2,6,6-tetramethyl-4-piperidyl)-N,N'- diformylhexamethylenediamine; N,N'-l,6-Hexanediylbis[N-(2,2,6,6-tetramethyl-4- piperidinyl)formamide], Bis(2,2,6,6,-tetramethyl-4-piperidyl)sebaceate, Polymer of 2,2,4,4-tetramethyl-7-oxa-3 ,20-diaza-dispiro [5.1.11.2] -heneicosan-21 -on and epichlorohydrin, 1,3-Propanediamine, N,N" -l,2-ethanediylbis-,polymer with 2,4,6- trichloro-l,3,5-triazine, reaction products with N-butyl-2,2,6,6-tetramethyl-4- piperidinamine.

HALS are also known by their commercial names, such as Chimassorb944, Tinuvin 622, Chimassorb 119, Cyasorb3529, Cyasorb 3346, Chimasorb2020, Uvinul5050, Uvinul4050, Tinuvin770, Hostavin N30, HA88.

According to some embodiments, the HALS is Chimassorb944.

None of the HALS are NOR-HALS.

According to some embodiments, the HALS has a decomposition temperature of more than 300°C, at times, above 350°C. In this connection it is noted that NOR-HALS decompose at 225°C, such as Tinuvin NOR371 having a decomposition temperature of 225°C.

The polymeric material described herein is characterized by being essentially transparent to visible light. As appreciated, transparency (pellucidity or diaphaneity) is a physical property that allows light to pass through the material without being scattered.

In the context of the present disclosure the term "essentially transparent" denotes that at least 50%, at least 60%, preferably at least 70% percent, at times between 70% to 80% or even between 70-90% visible light in the wavelength range of between 400nm to 700nm is transmitted.

The polymeric material disclosed herein is also characterized by its reflectance of visible light.

Thus, while being on the one hand transparent (i.e. light transmitting) the polymeric material is also to some (sufficient degree) light reflecting. In the context of the present disclosure the polymeric material is characterized by reflectance of up 30%, at times, between 10% to 30% or up to 20% of the light in the wavelength range of between 400 to 700nm. The polymeric material of the present disclosure are surprisingly characterize with dual characteristics, being both transparent and reflectant. Thus, while Ti(¾ particles which are not in the nanoscale (known as titanium dioxide white) significantly reflect visible light (and are thus provide white pigment to the polymers including them), it was now found that using nanoscale metal oxide particles together with polymers that may be configured into strong nets, webs or other open cell structures (and thus withstanding extreme climates typical in agriculture) are advantageous at least due to this dual characteristic.

The dual effect was further found advantageous in term crop yield. As shown in the non-limiting examples provided herein, the use of an aerating barrier (due to the openings), that is also light transmitting and light reflecting increased crop production.

Without being bound by theory, it is believed that these positively affected crop cultivation for at least the following reasons:

Aerating net - provided aeration for the pollination insects (such as the bumblebees). Aeration also enables good levels of C(¾ for optimized photosynthesis and lower temperatures inside the greenhouse.

Visible light transmittance - provided sufficient light (400-800nm or even 400-700nm) to the crop;

Visible light reflectance - resulted in an insect repelling effect.

As appreciated, one major problem in crop cultivation that is associated with insects is their capability to transmit viruses that infect the growing plants and may eventually lead to lose of the crop. In this connection, and without being bound by theory, it is suggested that the reflected visible light affects insects' behavior, by for example, causing disorientation in space which in turn cause the observed repel of insects. This is also evident by the fact that the plurality of openings of the polymeric material are characterized by an opening size that is larger than the size of the insects that need to be repelled (as further discussed below), and thus theoretically the insects may pass through the openings (but do not due to the repelling effect of the polymeric material). As also shown in Example 2 below, while in the control crates including standard nets of 40 mesh, a large number of insects passed through the nets, while in the tested crates with nets made of the polymeric material disclosed herein, the number of plants infected by virus was markedly reduced. Therefore the present invention provides means to suppress plants virus epidemics.

According to one particular embodiment, the polymeric material comprises a thermoplastic polymer that is a combination of at least high density polyethylene and Ti(¾ nanoparticles. According to some further embodiments, the combination includes also HALS that is suitable for HDPE. According to some embodiments, the HALS is Chimassorb 944.

The polymeric material described herein having both visible light transmission and visible light reflectance characteristics, may be used for a variety of applications. For example, it may be used in agriculture applications.

Thus, in accordance with a second aspect of the present disclosure there is provided an agricultural housing wherein at least a portion of the housing is formed from the polymeric material barrier disclosed herein.

The present invention is therefore suitable in blocking penetration of insects and in protecting against pests, while still providing the crop with sufficient visible light required for photosynthesis.

Non liming examples of insects include tobacco Whitefly (Bemisia-tabaci), Leaf miner, Aphids, Auchenorrhyncha, fruit flies and Thrips.

The polymeric material of the invention may be used for example for assist the cultivation of any type of agriculturally beneficial plant that is grown on a large scale for food, clothing, and other human uses. This includes, without being limited thereto flowers, vegetables, fruits or transplants in a variety of agriculture housing.

The term "agriculture housing" as used herein denotes any construction of physical structure to be used in crop protection without being limited by shape, height, design, type of cultivated crop etc. In other words, the housing is used to provide a barrier between the outer environment and the space within the housing in which the crop is cultivated.

According to some embodiments, the agriculture housing is in the form of an agriculture tunnel. Tunnel can be high tunnel, low tunnel walk in tunnel etc., as known in the art. According to some embodiments, the agriculture housing is in the form of a greenhouse, row cover and mulch (a mulch being known as a sheet that covers the ground).

According to some embodiments, the agricultural housing comprises at least a top section and a sides section, and at least a portion of the sides section is formed from the agricultural barrier disclosed herein.

In the context of the present disclosure, the term "at least a portion" is used to denote that at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90% of the housing is formed from the insect repelling barrier disclosed herein. In this context, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90% of the side walls (see below) of the housing are formed from the insect repelling barrier disclosed herein.

The "at least a portion" may be defined by a section of the housing. Thus, according to some embodiments, at least a portion of the tunnel, either at the sides and/or at the top section is formed from the agricultural barrier disclosed herein.

According to some embodiments, the agriculture housing is in the form of a net cover, with all the walls of the cover being formed from the barrier disclosed herein.

According to some embodiments, the agriculture housing is in the form of a tunnel for open field cultivation with at least part of the side walls of the tunnel being formed from the barrier disclosed herein.

In this connection, reference is made to Figure 1 and Figure 2 which are schematic illustrations of two exemplary agriculture housings that may be used in the present disclosure.

In Figure 1, there is illustrated a tunnel 10 having the dimensions typical of a "Walkln" tunnel and construction according to conventional growing tunnels for agriculture. Tunnel 10 comprises a top section 12 and sides section 14. The sides section 14 is composed from the barrier disclosed herein.

Top section 12 may be rigid (e.g. glass, fiberglass etc.) or be flexible screen (polymeric film) as well known and commonly used in agriculture. It may also comprise top ventilating openings. Referring now to Figure 2, there is illustrated an additional housing, in the form of a crate 20 specifically construed for this experiment, and comprising a top section 22 and sides section 24. The top section 22 and the sides 24 are all composed from the barrier disclosed herein.

The non-limiting Examples 1 and 2 provided herein below demonstrate the advantage of using the barrier disclosed herein for insect repelling which thereby results in reduction in virus infections and increase in crop yield.

As shown in the non-limiting Example 1 the type of the top wall films did not affect the number of insects entering the tunnel. Without being bound by theory, it was suggested that the insect replant effect was due to the nets used as side wall.

As shown in the non-limiting Example 2 the nets according to the present disclosure transmit light in the wavelength range of 400 to 700 nm similar to the control nets (without any titanium oxide) suggesting that introduction of nanoparticles of titanium oxide did not affected transmission of light. In addition, the nets according to the present disclosure transmits higher percentage of light in the wavelength range of 400 to 700 nm compared to the nets comprising titanium oxide as white pigment (i.e. not nanoparticles).

Without being bound by theory, it was suggested that introducing titanium dioxide in the form of nanoparticles permits transmission of light in the wavelength range of 400 to 700 nm sufficient to enable photosynthesis and cultivation of crop.

Further as shown in Example 2, the nets according to the present disclosure reflect a higher % of light in the wavelength range of 400nm to 700nm compared to the control nets (no titanium oxide) and a lower % compared to the nets comprising titanium oxide as white pigment.

Taken together, the results in Example 2 showed that the nets according to the present disclosure are capable of both transmitting and reflecting light in the wavelength range of 400nm to 700nm and as such are characterized by having a dual effect.

Without being bound by theory, it was suggested by the inventors that this dual effect provides the nets according to the present disclosure a unique advantage in enabling on one hand, transfer of light to allow grow of crop and on the other hand provides protection to the growing crop by repelling insects. In addition, the results in Example 2 show that the number of plants infected with viruses was markedly reduced in the crates covered with the nets prepared according to the invention compared to commercial net without titanium oxide. Without being bound by theory, the inventors have suggested that since both nets have similar mesh size, the replant effect of the nets according to the present disclosure is specific to the use of titanium oxide in the form of nanoparticles.

In accordance with another aspect, the present invention provides a method of producing a barrier as disclosed herein, the method comprising mixing a combination of at least one thermoplastic polymer and the nanoparticles under condition which cause the combination to form into a melt; and processing said melt into a polymeric material having a plurality of openings.

In some embodiments, the combination comprises HALS. In some further embodiments, the combination does not include NOR-HALS.

In some embodiments, the conditions comprise heating to a temperature above the decomposition temperature of NOR-HALS, i.e. above about 225°C.

In some embodiments, the mixing is under heat and/or shear forces. In some other embodiments, mixing is in an extruder whereby filaments (e.g. monofilaments) are extruded which are then interwoven, or otherwise combined into a grid like structure as herein defined.

In some embodiments, the polymeric material is provided by stretching a film and forming from the stretched film tapes (cutting tapes) that are then used as filaments for forming a grid like structure.

In accordance with another aspect, the present invention provides an agricultural method comprising cultivating crop within a housing wherein at least a portion of said housing comprises the barrier as described herein. In some embodiments, the housing has a top section and a sides section and at least a portion of the sides walls is of the barrier subject of the present disclosure.

It is noted that by the use of the barrier disclosed herein, the need for pesticides is greatly reduced. This is significant, for many reasons. For example, today there are strict regulations around the world, e.g. in Europe for pesticides in the crop. So the crop produced by the present technology can be beneficial and thus easily marketed.

DESCRIPTION OF NON-LIMITING EXAMPLES

Preparation of Nets

The nets tested in this study were prepared from high density polyethylene (HDPE) mixed together with 0.5% (w/w) titanium oxide (Ti(¾) nanoparticles (non- doped) having an average size of 20nm and 0.5% (w/w) hindered amine light stabilizer (HALS) Chimassorb944. The nets were woven from 200-300 micron monofilament and have a hole size of 40x40 mesh.

The study included measurement of the following optical properties:

Visible light transmission ( "%T") was measured using spectrophotometer with a sphere. The light transmission was measured at different wavelengths between 200nm to 2500nm and the integral (area below the transmission curve) between certain wavelengths was calculated. The result of the integral calculation was then divided by the differences of the measured wavelength (namely subtracted difference).

For example total light transmission between 400nm to 700nm was determined by measuring the integral of the transmission spectrum between 400nm to 700nm and dividing the result (namely, the calculated integral) by the difference of the numerical value of the wavelengths calculated to be in this example 300nm.

The spectral region of the wavelengths 280nm to 380nm corresponds to the UV range and it is important for bees' navigation, insects' navigation and crop development. The wavelength region of 400nm to 700nm relates to photosynthesis active radiation (PAR). The wavelength region of 750nm to 1500nm is referred to as near IR (NIR) heat coming from the sun. The term diffused light 400 - 700 is used in agriculture films and indicates the amount of light passing through the film and nets that is scattered (does not continue straight forward). The term %R represents the reflectance and indicates the amount of light the film and nets reflects in a certain measured wavelength range. FIELD TRIALS:

Example 1 - Tunnels:

The nets as detailed above were used as side walls in walk in tunnels as shown in Figure 1.

Two films were used as top section:

(1) low density polyethylene (LDPE) and linear LDPE (LLPDE) mixed with 0.5% HALS and

(2) an antivirus film comprising LDPE and LLDPE mixed with 0.5% HALS, 0.25% benzotriazole and 0.5% benzophenone.

During the trials the number and type of insects that entered the tunnel was measured at several time points.

Results:

Table 1 shows the amount of Thrips and Bemisia-tabaci (whitefly) in tunnels having as side walls the nets comprising nanoparticles of T1O₂ (non-doped) and as top wall either (1) or (2) as detailed above.

Table 1 - The amounts of Thrips and Bemisia-tabaci in tested tunnels

The results indicated that the type of the top wall films did not affect the amount of measured insects. Use of a film 1 that included LDPE and LLDPE with only HALS as a top was shown to be as efficient as film 2 that included also the antiviral components. These results strongly suggested that the insect replant activity observed herein is due to the nets used as side wall as the result was not dependent on the composition of the top film.

Example 2 - Experimental crates:

Crates with nets forming the side walls and top walls were used. As a control, commercial nets produced from HDPE, 0.5% HALS and organic UV absorber were used (manufactured by Polysack, catalog no. 39224402501).

The organic UV absorbers used in this industry are:

1. 2-Hydroxy-4-n-octoxybenzophenone

2. 2,4-Bis(2,4-dimethylphenyl)-6-(2-hydroxy-4-isooctyloxyphenyl)-l,3,5- triazine and

3. Phenol, 2-(5-chloro-2H-benzotriazole-2-yl)-6-(l,l-dimethylethyl)-4-methyl (marketed under the commercial names Chimassorb81 Cyasorbl l64 and Tinuvin326 respectively).

The Experimental set up is shown in Figure 2

The study was conducted during the summer of 2012 in Moshav Ben Hanan, Israel. Ten crates (80cmx80cmx70cm) were used. The crates were arranged as shown in Table 2 and included five control crates (no titanium oxide) (#1) and five crates with the nets of the invention (#2).

Two courgette plants were planted in each crate and in addition two plants were planted between each two adjacent crates. The plants were grown according to regular procedures. Yellow sticky traps were placed in each crate and in several locations between adjacent crates. The number of virus infected plants was determined by visual inspection.

Table 2 - Experimental Settings

(+) denotes that a trap was placed and (-) denotes that no trap was placed. 1 and 2 represent the nets type as detailed above. The experimental time lines are shown in Table 3.

Table 3 - Experimental time lines:

Optical measurements:

Results:

Table 4 shows the optical measurements conducted on the crates having as walls standard nets or the nets comprising nanoparticles of Τί(¾ as detailed above.

Table 4 - Light measurements

As can be seen in Table 4, the nets comprising the nanoparticles of titanium dioxide (Net type #2) transmitted light in wavelength range of 400nm to 700nm efficiently and almost as a commercial net without titanium oxide (Net type #1).

Namely, the introduction of titanium oxide in the form of nanoparticles did not affect the transmission of visible light.

In addition, an increase in the % of reflected light in the wavelength range of 400nm to 700nm was observed in the nets according to the invention (16.7%) compared with the commercial nets without any titanium oxide (9.3%). The %R of the UV light in the range of 280nm to 380 nm was not different between the two nets. Table 5 shows a comparison between nets comprising titanium dioxide in the form of nanoparticles with different mesh size (A-25mesh, B-40mesh and C-50mesh), no titanium oxide (D) and comprising titanium oxide in the form of white pigment with different mesh size (E-40mesh and F-50mesh).

Table 5 - Light measurements

PAR refers to photosynthetically active radiation and corresponds to wavelength range of 400 nm to 700 nm

As can be seen in Table 5, the nets comprising titanium dioxide in the form of nanoparticles transmitted light in the wavelength range of 400 to 700 nm similar to the nets without any titanium oxide.

The nets comprising titanium oxide as white pigment (i.e. non-nanoparticles) transmitted a lower percentage of light in the wavelength range of 400 to 700 nm (-62% and 54%) compared to the nets with the titanium oxide nanoparticles (about 76% in the 40 mesh and 50 mesh). In addition, although there was a reduction in the % of reflected light in the wavelength range of 400nm to 700nm in the nets according to the invention compared with the nets comprising titanium oxide as white pigment, still the % reflectance was higher than the control nets without any titanium oxide.

Taken together, these results showed that the nets according to the present disclosure, namely comprising titanium oxide as nanoparticles are capable of both transmitting and reflecting light in the wavelength range of 400nm to 700nm and as such are characterized by having a dual effect.

It was suggested by the inventors that this dual effect provides the nets according to the present disclosure a unique advantage in enabling on one hand, transfer of light to allow grow of crop and on the other hand provides protection to the growing crop by repelling insects.

Crop measurements:

The capacity of the nets to block penetration of insects was assessed by measuring the number virus infected plants in cultivation of courgette (zucchini).

Results

The results of these experiments after the first counting and the second counting are shown in Tables 6A and 6B, respectively.

Table 6A - Results obtained 19 days after planting

Treatment Infected with virus

% No. of plants

No cover/crate 100 2.0

1 20 0.4

2 0 0.0 Table 6B - Results obtained 30 days after planting

The results provided in Tables 6A and 6B show that the number of courgette plants infected with viruses was markedly reduced in the crates covered with the nets prepared according to the invention, namely, nets comprising the nanoparticles of titanium dioxide (Net type #2) compared to commercial net without titanium oxide (Net type #1).

This marked decrease in the viral infected plants may be attributed to the fact that fewer insects are passing through the nets and thus entering the crates and infecting the plants with virus.

Since both nets have similar mesh size, these results clearly indicated that the replete effect of the nets of the invention was specific and not due to the size of the nets.

Claims

CLAIMS:

1. An agricultural barrier comprising a polymeric material having a plurality of openings, said polymeric material comprising:

(a) at least one thermoplastic polymer, and

(b) one or more non-doped metal oxide nanoparticles.

2. An agricultural barrier comprising a polymeric material having a plurality of openings, said polymeric material comprising:

(a) at least one thermoplastic polymer, and

(b) one or more nanoparticles consisting of metal oxide.

3. The agricultural barrier of Claim 1 or 2, wherein said polymeric material comprises at least one hindered amine light stabilizer (HALS).

4. The agricultural barrier of any one of Claims 1 to 3, wherein said polymer material comprises spaced apart plurality of openings.

5. The agricultural barrier of any one of Claims 1 to 4, having between 15 to 60 openings per inch length.

6. The agricultural barrier of Claim 5, having 30 to 50 openings per inch length.

7. The agricultural barrier of any one of Claims 1 to 6, wherein said thermoplastic polymer is an organic polymer.

8. The agricultural barrier of any one of Claims 1 to 7, wherein said thermoplastic polymer is a selected from the group consisting of polyolefin and co-polymers thereof, polycarbonate, and polyvinyl chloride.

9. The agricultural barrier of Claim 8, wherein said thermoplastic polymer is selected from the group consisting of polyethylene, polypropylene, polycarbonate, poly(ethylene-co-tetrafluoroethylene), polyvinyl chloride, polyethylene vinyl acetate, polyethylene butyl acrylate.

10. The agricultural barrier of Claim 9, wherein said thermoplastic polymer is a high density polyethylene or polypropylene.

11. The agricultural barrier of any one of Claims 1 to 10, wherein said nanoparticles comprise a transition metal.

12. The agricultural barrier of Claim 11 , wherein the metal oxide is selected from the group consisting of titanium dioxide (Ti(¾), zinc oxide (ZnO), zirconium dioxide (Zr(¾), hafnium dioxide (Hf(¾), cadmium oxide (CdO), mercury oxide (HgO), Chromium oxide (CrO) and Copper oxide (CuO).

13. The agricultural barrier of Claim 12, wherein said nanoparticles comprise T1O2 nanoparticles.

14. The agricultural barrier of Claim 13, wherein said nanoparticles consists of Ti0₂.

15. The agricultural barrier of any one of Claims 1 to 14, wherein the thermoplastic polymer is a high density polyethylene and the nanoparticles are T1O2 nanoparticles.

16. The agricultural barrier of any one of Claims 1 to 15, wherein said metal oxide nanoparticles have an average size in the range of lnm to lOOnm.

17. The agricultural barrier of Claim 16, wherein said nanoparticles have an average size in the range of 20nm.

18. The agricultural barrier of any one of Claims 1 to 17, wherein said polymeric material comprises a weight/weight (w/w) amount of said nanoparticles within the range of between 0.01% to 5%.

19. The agricultural barrier of Claim 18, wherein the amount of said nanoparticles is within the range of between 0.05% to 2%.

20. The agricultural barrier of any one of Claims 1 to 19, having at least 50% light transmission in the wavelength range of between 400 to 700nm.

21. The agricultural barrier of Claim 20, having at least 70% light transmission in the wavelength range of between 400 to 700nm.

22. The agricultural barrier of any one of Claims 1 to 21, having less than 20% light reflectance in the wavelength range of between 400 to 700nm.

23. The agricultural barrier of Claim 22, wherein said light reflectance in the wavelength range of between 400 to 700nm is effective to repel insects from the barrier.

24. An agricultural housing wherein at least a portion thereof is formed from an agricultural barrier according to any one of Claims 1 to 23.

25. The agricultural housing of Claim 24, in the form of a tunnel or a greenhouse.

26. The agricultural housing of Claim 24 or 25, comprising at least a top section and side sections, at least a portion of said side sections being formed from the agricultural barrier of any one of Claims 1 to 23.

27. A method of producing an agricultural barrier as defined in any one of Claims 1 to 23, the method comprising mixing a combination of at least one thermoplastic polymer and non-doped metal oxide nanoparticles under condition which cause the combination to form into a melt; and processing said melt into a polymeric material having a plurality of openings.

28. A method of producing an agricultural barrier as defined in any one of Claims 1 to 23, the method comprising mixing a combination of at least one thermoplastic polymer and nanoparticles consisting of metal oxide, under condition which cause the combination to form into a melt; and processing said melt into a polymeric material having a plurality of openings.

29. The method of Claim 27 or 28, wherein said combination comprises HALS.

30. The method of Claim 29, wherein said combination does not include NOR-HALS.

31. The method of any one of Claims 27 to 30, wherein said mixing is under shear forces.

32. An agricultural method comprising cultivating crop within a structure wherein at least a portion of said physical barrier comprises the agricultural barrier of any one of Claims 1 to 23.

33. The agricultural method of Claim 32, wherein said structure has a top wall and side walls and at least a portion of said side walls is of said agricultural barrier.