PARTICLES FOR RELEASING INGREDIENTS

Abstract

This invention relates to particles (1) with a controllable release of at least one pheromone, wherein a) the particle (1) has a core (2) which is surrounded by one or more layers (4, 6), and b) the core (2) and at least one layer (4, 6) surrounding the core (2) comprises at least one pheromone to be released, wherein the core (2) and/or at least one layer (4, 6) surrounding the core (2) comprises a substrate for binding or for absorbing the at least one pheromone to be released, wherein the substrate is capable of dispensing the absorbed pheromone in a delayed manner, and the substrate comprises zeolite.

Claims

1. Particles (1) with a controllable release of at least one pheromone, wherein a) the particle (1) has a core (2) which is surrounded by one or more layers (4, 6), and b) the core (2) and at least one layer (4, 6) surrounding the core (2) comprises at least one pheromone to be released, wherein the core (2) and/or at least one layer (4, 6) surrounding the core (2) comprises a substrate for binding or for absorbing the at least one pheromone to be released, wherein the substrate is capable of dispensing the absorbed pheromone in a delayed manner, and the substrate comprises zeolite.

2. The particles (1) according to claim 1, characterized in that the core (2) and the at least one layer (4, 6) surrounding the core (2) comprise different pheromones.

3. The particles (1) according to claim 1 or 2, characterized in that at least one intermediate layer (3, 5) is provided between the core (2) and the at least one layer (4, 6) surrounding the core (2) and including the pheromone and/or between two layers (4, 6) surrounding the core (2) and including pheromone.

4. The particles (1) according to claim 3, characterized in that the intermediate layer (3, 5) includes a polymer, preferably a modified or non-modified biopolymer, or a layered material.

5. The particles (1) according to any one of claims 1 to 4, characterized in that the core (2) and/or at least one layer (4, 6) surrounding the core (2) includes a porous substrate and/or a compound comprising a macromolecular cavity.

6. The particles (1) according to any one of claims 1 to 5, characterized in that the core (2) and/or at least one layer (4, 6) surrounding the core (2) includes an inorganic porous selected from the group consisting of microporous minerals, phyllosilicate, preferably clay mineral, and combinations thereof.

7. The particles (1) according to any one of claims 1 to 6, characterized in that the core (2) and/or at least one layer (4, 6) surrounding the core (2) includes a compound comprising a macromolecular cavity selected from the group consisting of metal-organic frameworks (MOF), macrocyclic compounds, preferably oligosaccharides or cyclic polysaccharides, calixarenes, and combinations thereof.

8. The particles (1) according to any one of claims 1 to 7, characterized in that the core (2) includes an inorganic porous substrate and at least one layer (4, 6) surrounding the core (2) includes a compound comprising a macromolecular cavity.

9. The particles (1) according to any one of claims 1 to 8, characterized in that the particle (1) comprises a surface coating (7), preferably a hydrophobic surface coating (7).

10. A composition including particles (1) according to any one of claims 1 to 9, wherein the particles (1) are suspended in an aqueous medium.

11. The composition according to claim 10, characterized in that the aqueous medium includes at least one tenside.

12. Use of a particle (1) according to any one of claims 1 to 9 or a composition according to claim 10 or 11 as a plant protection product.

13. A method for controlling plant damaging organisms, including bringing plants and/or the soil in which the plants grow into contact with an effective quantity of particles (1) according to any one of claims 1 to 9 or a composition according to claim 10 or 11.

Description

[0092] The present invention is explained with reference to the following figures and examples, however without being limited to these.

[0093] FIG. 1 shows a particle 1 according to the invention, comprising a core 2 and several layers 4 and 6 surrounding the core. The core 2 and the layers 4 and 6 include at least one active plant protection ingredient which is released over time. Intermediate layers 3 and 5 are provided between the core 2 and the layer 4 or between the layers 4 and 6, respectively, which is to prevent, inter alia, diffusion of the active plant protection ingredients, particularly pheromones, between the core 2 and the layer the layers 4 and 6 to the greatest possible extent. A surface coating 7, which is preferably hydrophobic, is provided on the outer side of the particle according to the invention.

[0094] FIG. 2 shows another particle 1 according to the invention, which comprises a core 2, a layer 4 surrounding the core, an intermediate layer between the core 2 and the layer 4, and a surface coating 7. In this alternative embodiment compared to FIG. 1, the particle 1 according to the invention includes a layer 4 instead of two layers comprising active plant protection ingredients, and this layer comprises an active plant protection ingredient like the core 2.

[0095] FIG. 3 shows a GC/MS measurement that revealed that the pheromone 8-methyl-2-decanol propanoate is still released even after 10 weeks of storing zeolite particle (see Example 3).

[0096] FIGS. 4 to 6 show the values listed in the table of Example 4.

EXAMPLES

Example 1

[0097] 40 kg of natural zeolite were ground using an impact mill to an average fineness of 5 μm. The temperature of up to 120° C. that developed in the process had the effect that the mineral, which was originally charged with 8.5% water, was dried to a water content of 2.9%. In this phase, a solution comprising 5.0 g pheromone 1 (capric acid methyl ester) dissolved in 2 liters of ethanol (96%) was sprayed onto the rotating zeolite, wherein the solvent evaporated immediately and an even distribution of the pheromone across the total amount of zeolite was achieved. The pheromone was immediately latently bound into the pore structure and to the surface of the zeolite.

[0098] 1 liter of a hot solution (ca. 60° C.) of 50 g corn starch in water was sprayed onto this intermediate product, and an insulating intermediate layer was formed. Then 6.6 g of the aqueous solution of a second effective pheromone (8-methyl-2-decanol propanoate), complexed with cyclodextrin at a ratio of 1:1 (see Example 2), was sprayed on and dried as a second active ingredient layer. After adding a total of 100 g fine-particled calcium stearate (under 2 μm), the spray powder obtained was cooled and filled into polyethylene bags.

[0099] The fine-particled powder was easily dispersed in water. This quantity was evenly applied on 10 ha of agricultural area. After 10 weeks, the rate of unfertilized corn rootworm females was about 55-60%. A value that is comparable to the value achieved using highly toxic insecticides, which in addition are used at quantities more than 100 to 1000 times higher (kill rate of the relevant females). This shows that pheromone release and thus the disorientation effect achieved was sustained over the entire period of 10 weeks.

Example 2

[0100] The pheromone complex with cyclodextrin used in Example 1 was prepared as follows:

[0101] 0.1 mol cyclodextrin 7 (CAVAMAX 7) (initial weight 114 g) were dissolved in 2500 mL water at 60° C. and 0.1 mol methyldecanol-yl-propanoate were added by dropping as pheromone (active against corn rootworm). After about one hour, the 1:1 complex that had formed was filtered off the suspension that had cooled down in the meantime, washed with water, then dried. The solid complex contained about 17% of active pheromone agent.

[0102] This complex was brought back into a soluble form by adding anionic tensides and thus prepared for spraying onto the substrate.

[0103] 6.6 g of the dried (7.4 g of the wet) pheromone/cyclodextrin complex were suspended with 0.3 g sodium dodecylsulfate in 50 mL water, the filled up to 300 mL water and stirred until the complex largely transitioned into a solution or a suspension that did no longer settle was obtained. This aqueous pheromone preparation was safely sprayed onto the substrate according to Example 1 (risk of explosion).

Example 3

[0104] To study the bonding capacity of the pheromone 8-methyl-2-decanol propanoate to natural zeolite, 200 g of zeolite particles were mixed with 25 mg pheromone in 10 mL ethanol (96%) (see Example 1, paragraph 1). The zeolite particles that were treated with pheromone and dried were transferred into an Erlenmeyer flask and mixed with distilled water such that the zeolite particles were completely covered with water. The water/zeolite suspension was stirred for 60 minutes at room temperature using a magnetic stirrer. Then the water was removed and the zeolite particles were dried. After 10 weeks of storage at room temperature and 85% humidity, GC/MS (gas chromatography/mass spectrometry) was used to check if the particles still released pheromone into the environment. The volatile substances in the samples were eluted from the particles by thermal desorption before the GC/MS examination. FIG. 3 shows that the particles, after 10 weeks of storage and washing, are still capable of releasing 8-methyl-2-decanol propanoate.

Example 4

[0105] In the case of the corn rootworm (Diabrotica virgifera virgifera), suitable plant protection products must be applied to the growing corn seedlings by end of June/mid-July. It is particularly the flight period of the adult beetle that is of interest for the disorientation method. It starts at the end of June and ends at the beginning of October. The pheromones that cause the disorientation must therefore be available over a period of 12-14 weeks. For an optimal effect, 16 weeks (=˜4 months) including about 2 weeks of application window have to be bridged. This means that the pheromones must be released for at least 16 weeks. Release tests were carried out to find out if pheromone release over this period of time is possible with the particles according to the invention. In addition, comparative tests were made with particles of a different composition.

[0106] Particles 1 and 2 correspond to the particles from Example 1 (zeolite core with intermediate layer of corn starch and a second active ingredient layer comprising cyclodextrin). Particles 3 consist of crystalline clay (sepiolite) and are produced like particle 1 (see Example 1, only sepiolite is used instead of zeolite). Like particle 3, particles 9 were prepared with talc, particles 10 with montmorillonite (phyllosilicate), particles 6 with kaolin, particles 7 with micro mica, and particles 8 with quartz. In addition, particles were prepared with a talc and montmorillonite core, which like the zeolite particles 11 and 12 do not include an intermediate layer of corn starch and no other outer layer comprising pheromone-containing cyclodextrin. The uncoated talc particles are the particles 4 and the uncoated montmorillonite particles are the particles 5.

[0107] Particles 11 and 12 correspond to particles 1 and 2, respectively, wherein these do not comprise an outer second active ingredient layer and corn starch layer. Particles 1 and 11 also had a synthetic zeolite A with a pore size of 4 Å instead of a core of natural zeolite.

[0108] To ensure comparability, all particles or minerals were ground to a fineness of 5 μm in diameter before they were charged with the same pheromone.

[0109] Particles 1 to 12 were charged with pheromones as described in Example 1 or 2, respectively, in that 5 g pheromone 1/40 kg were provided in the core and, where required, additional 3.3 g pheromone 2 in the coating, in total 8.3 g of active substance/40 kg, i.e. 0.2 mg/g. Particles 1 to 12 therefore just differ in that the substrate materials for the pheromone(s) are different and in that they comprise a second active ingredient layer or not (see explanations below).

[0110] To examine the release of the pheromones, a glass vessel with a volume of 950 mL (ca. 1 L) was filled over an air-permeable fritted glass filter with 5 g of the respective particles and flooded with air at a temperature of 23° C. and 85% humidity, such that a complete air exchange of the entire volume was achieved within 1 h. The pheromone quantity emitted from the particles and contained in the volume flow was measured using gas chromatography at an measuring accuracy of 0.01 μg/L, and documented. This test can be used to simulate both the uniformity and the duration of the pheromone release in nature.

[0111] The results of measuring the pheromone release (emission μg/h=μg/L air) are shown in the following table:

TABLE-US-00001 Particle 1 0.40 0.41 0.41 0.40 0.36 0.35 Particle 2 0.30 0.30 0.28 0.25 0.28 0.30 Particle 3 0.48 0.50 0.55 0.50 0.52 0.60 Particle 4 0.60 0.72 0.70 0.74 0.68 0.70 Particle 5 0.50 0.52 0.54 0.52 0.50 0.58 Particle 6 0.52 0.50 0.53 0.50 0.48 0.40 Particle 7 0.65 0.75 0.77 0.80 0.70 0.60 Particle 8 0.85 0.90 0.90 0.88 0.90 0.92 Particle 9 0.55 0.64 0.65 0.66 0.60 0.63 Particle 10 0.52 0.50 0.48 0.50 0.50 0.52 Particle 11 0.43 0.44 0.40 0.42 0.44 0.40 Particle 12 0.34 0.33 0.31 0.30 0.31 0.30 Time (total 1 h 5 h 10 h 24 h .sup.  168 h   .sup.  700 h    flow time) 1 day 1 week 1 month

TABLE-US-00002 Particle 1 0.33 0.27 0.24 0.22 0.14 Particle 2 0.31 0.28 0.30 0.32 0.29 Particle 3 0.62 0.40 0.20 0.05 0.00 Particle 4 0.65 0.30 0.03 0.00 — Particle 5 0.60 0.38 0.18 0.04 0.00 Particle 6 0.33 0.28 0.20 0.00 — Particle 7 0.45 0.18 0.00 — — Particle 8 0.43 0.04 0.00 — — Particle 9 0.64 0.42 0.27 0.10 0.00 Particle 10 0.45 0.37 0.16 0.10 0.00 Particle 11 0.38 0.25 0.20 0.08 0.00 Particle 12 0.35 0.30 0.28 0.10 0.00 Time (total 1000 h 1400 h 2100 h 2500 h 3000 h flow time)   ~2 mo   ~3 mo   ~4 mo

[0112] The particles examined and listed in the above table have the following structure and can be produced using the method according to Example 1, wherein instead of a zeolite core, another material is used for the core (see below): [0113] Particle 1 Core of synthetic zeolite A (pore size 4 Å) with a second active ingredient layer as shown in Example 1 [0114] Particle 2 Core of natural zeolite with a second active ingredient layer as shown in Example 1 [0115] Particle 3 Core of crystalline clay (sepiolite) with a second active ingredient layer as shown in Example 1 [0116] Particle 4 Core of talc without a second active ingredient layer as shown in Example 1 [0117] Particle 5 Core of montmorillonite (phyllosilicate) without a second active ingredient layer as shown in Example 1 [0118] Particle 6 Core of kaolin with a second active ingredient layer as shown in Example 1 [0119] Particle 7 Core of micro mica with a second active ingredient layer as shown in Example 1 [0120] Particle 8 Core of quartz with a second active ingredient layer as shown in Example 1 [0121] Particle 9 Core of talc with a second active ingredient layer as shown in Example 1 [0122] Particle 10 Core of montmorillonite (phyllosilicate) with a second active ingredient layer as shown in Example 1 [0123] Particle 11 Core of synthetic zeolite A (pore size 4 Å) without a second active ingredient layer as shown in Example 1 [0124] Particle 12 Core of natural zeolite without a second active ingredient layer as shown in Example 1

[0125] The results shown in the above table (see also FIGS. 4 to 6) show that particles comprising a zeolite core (particles 1, 2, 11, and 12) compared to particles comprising a core made of other materials (particles 3 to 10) are capable of releasing relatively constant quantities of pheromones over a relatively long period of time. The use of natural zeolites appears to be particularly advantageous, since these are even capable of constantly releasing pheromones over 4 months. In the case of synthetic zeolites, it appears to be particularly advantageous to provide a two-layer material (combination with cyclodextrin, for example; see Example 2). In such a case, pheromones can be released into the environment relatively constantly for up to 3 months.

[0126] The results for particles 3 to 10 show that these release the pheromones irregularly over the period of time observed compared to particles 1 and 2 according to the invention (a relatively large quantity at the beginning of the series of measurements, at the end a small quantity or none), or they release them over a relatively shorter period of time. Unlike particles 1 and 2, particles 11 and 12 do not have a second active ingredient layer. While particles 11 and 12 release pheromones fairly constantly over a relatively long period of time, the release period is shorter than for particles 1 and 2.

[0127] These results document impressively that particles according to the invention having a structure like particles 1 and 2 are particularly advantageous, whereas particles having the same core but no second active ingredient layer (particles 11 and 12) display a shorter period of releasing pheromones.