CS226011B2 - Insecticide or nematocide granules - Google Patents

Description

The invention relates to insecticidal or nematocidal granules.

Methyl [2- (dimethylamino) -N] (methylaminocarbonyl) oxy] -2-oxoethanemidethioate7, hereafter referred to as the trivial name examyl, is extremely effective as an insecticide and non-contact broad spectrum type. This compound is particularly suitable for introducing soil for treatment prior to plant growth. The long-term insecticidal and nematicidal effect of oxamyl is impaired by its disappearance in the soil and is known to cause rainfall, aeration, sunlight, alkalinity and elevated temperatures to accelerate. There are such safety problems in handling oxamyl as it has a high toxicity, for example LD 50 at 5.4 mg / kg.

The use of slow release systems of applied insecticides is known. The problem with such systems, however, is that they show an early reduction in effect. This is due to the presence of a protective material which reduces the usability of the insecticide.

Therefore, there is a need to prolong the excellent insecticidal and nematicidal effect of oxamyl without impairing its initial effect. There is also a need to improve safety in handling oxamyl.

Controlled release granules have been unexpectedly discovered according to the present invention, which gradually release oxamyl in the soil and significantly increase its residual insecticidal and nematode effect without significantly reducing its initial effect. These granules have such reduced mammalian toxicity.

The essence of the insecticidal or non-methylcell granules according to the invention is that they are composed of an inert carrier in conjunction with methyl-2- (dimethylamino) -N- (netylaninocarbonyl) -exx7226011

-2-oxoethsimide thioate as an active ingredient and a protective material selected from the group consisting of polystyrene, styrene styrene containing up to 5% by weight comonomer, polymerized unsaturated polyester / styrene, urea-formaldehyde resin, vinylidene chloride copolymers containing up to 10% by weight comonomer, petroleum waxes is a paraffin wax, optionally mixed with up to 50% by weight of modifiers selected from low molecular weight polyethylenes, ethylene / vinyl acetate or polyterpenes, polyolefins, or mixtures thereof.

Diatomaceous earth or stpulgite is preferably used as the inert carrier.

It is preferred that the inert support is impregnated or coated with paraffin wax as a protective material, optionally in combination with up to 50% by weight of low molecular weight polyethylene as modifiers.

The invention relates to three different types of controlled release granules. In type (1), the inert mineral carrier is impregnated with an effective amount of oxemyl and then coated with a thin layer of protective material. In Type (2), the inert mineral carrier is coated or impregnated with a physical mixture of an effective amount of oxsyl and a protective material. When the granules are impregnated or coated with the composition, it depends on the porosity of the carrier. Finally, in type (3), the inert mineral carrier is impregnated with an effective amount of oxamyl and coated with a thin layer of a protective material that physically contains oxemyl.

Protective materials are high molecular weight substances that are capable of forming continuous films. Materials suitable for the purposes of the present invention are those which absorb water in a proportion not greater than about 0.2%. The granules of the invention prepared from a suitable protective material should be capable of releasing oxemyl in water at a temperature of 20 ° C at a rate not greater than 80% in four hours.

The granules of the invention are made from an inert mineral carrier. The term inert describes a msterial which does not react with oxemyl and which is practically insoluble in water. Preferred carriers are fused ettapulgite such as Florex LVM manufactured by Floridin Company and diatomaceous earth such as Celatom MP-78 from Eagle-Picher Industries. Longer types of carriers that can be used include other silicates, and various types of kaolin, attapulgite, montmorillonite, calcium carbonate, talc, crushed bricks, ground corn sticks and pyrophyllite.

If more porous materials are used, such as diatomaceous earth, the granules are impregnated with oxemyl / types / 1 / and / 3 / e / or mixtures of oxamyl and a protective material (type / 2 / J). it is preferable that oxemyl and the protective material be on the outside of the granule or close to the surface.

The amount of oxamyl present in the granules is between about 0.1 and 20% by weight, suitably about 0.5 and 15% by weight, preferably about 1 and 12% by weight. The final controlled release dry granules 8 contain about 4 to 30% of the protective material. If desired, the granules may contain other granules. the necessary additives, for example oxamyl or polymer stabilizers such as phosphoric acid, bactericides and various coloring agents to mark the treated area. The granules may have a regular or irregular shape and have a longest linear dimension of 300 to 5,000 micrometers (50 to 4 mesh).

As already mentioned, the granules of the invention should be able to release oxemyl in water at a temperature of 20 ° C at a rate of not more than 80% of four hours. For some purposes, the release rate should preferably not be greater than about 25% in four hours. The release rate can easily be determined when the granules are placed in water at 20 ° C for four hours. The amount of granules and water used should be sufficient to prepare a 3.5% oxsyl solution when all oxemyl is released. The amount of free oxamyl in the aqueous phase is determined by comparing the measured index with the refractive index of known oxamyl solutions.

The slow release granules 8 of the present invention are those materials in which the water absorption rate is not greater than about 0.2 as measured by ASTM D-570. This standard, known to those skilled in the art, is described in the Book of ASTM Standards and its features are set forth below. The absorption rates for various protective materials are available in Modern Plastice Encyclepedie, 1979-80 Edition, and the main data are presented below.

In summary, test D-570 is performed as follows:

Standard ASTM D-570

The sample, 3.2 mm thick, was dried in an oven at 50 ° C for 24 hours, cooled in a desiccator and weighed immediately. The sample is then immersed in water at 40.4 ° C for 24 hours. After removal, the sample is wiped with a cloth and weighed immediately. The weight gain is denoted as percent weight gain. For materials that lose some soluble mass during immersion and that the sample has to be re-dried, reweighed and designated as the percentage of loss of soluble mass. The sum of percent weight gain and percent loss of soluble mass is equal to percent water absorption.

Particular protective materials that are particularly preferred include petroleum waxes or polymers such as polystyrene, styrene copolymers with a small amount of other comonomers, polymerized unsaturated polyester styrene and urea-formaldehyde resins, vinylidene chloride copolymers, and polyolefins. Mixtures of the aforementioned protective materials, in particular mixtures of petroleum waxes and polyolefins, are also suitable.

The polystyrenes which can be used to produce the slow release granules of the invention have a molecular weight of about 30,000 to about 500,000 and preferably have a molecular weight of about 150,000 to about 250,000. Many polystyrenes are commercially available and are particularly useful as a protective material an effective product known under the protected name Shell 314®. Such a styrene copolymer containing up to about 5 S of other comonomer units is effective. Among the comonomers, those which do not cause a large increase in the permeability of polystyrene may be used, including acrylic monomers, such as methyl acrylate, butadiene, and in particular acrylonitrile.

Unsaturated polyester-styrene systems are styrene solutions of polyester derived from unsaturated anhydrides such as maleic anhydride and various glycols. These liquids are cured to complex cross-linked polymers using peroxide catalysts. Such systems are commercially available and are described in Modern Plastice Encyclopedia, 1970-80 Edltion, pp. 55-58 (McGraw-Hill Publishing Co.), the features of which are set forth below.

Urea-formaldehyde resins suitable as protective materials according to the invention are known in the art. The ratio of urea to formaldehyde in the resin is not critical, but a ratio of not more than 1: 1 is preferred, and even more preferably a ratio of about 2: 1.

Vinylidene chloride copolymers are also suitable protective materials. Vinylidene chloride itself is unsuitable and must be copolymerized with the monomers in order to improve its handling properties, but there is no appreciable effect on the protective properties. Such monomers are known to those skilled in the art and include ecrylates and vinyl chloride. Preferably, the comonomer content should not be greater than about 10% by weight of the vinyl chloride copolymer. A number of such vinylidene chloride based materials are commercially available. Particularly effective is the Dařen 220 ® material supplied by V. B. Qrace Co..

A large number of polyolefins are suitable as a protective material. Included in this group are low melting polyethylenes, oxidized polyethylene or ethylene copolymers containing up to about 40% comonomers such as ethylene / vinyl acetate.

Petroleum waxes, such as paraffin wax, may be used alone as protective materials or may be blended with up to about 50% of the modifiers or blend of modifiers. The modifiers serve to increase the softening temperature and improve the stiffness of the wax. Suitable modifiers include low molecular weight polyethylenes (e.g., Epolene C-10® or E-10® supplied by Eastman), microcrystalline waxes from petroleum, ethylene / vinyl acetate (e.g. Elvax ® from Du Pont) and polyterpenes (e.g. Piccolytes® from Hercules).

The granules of the present invention can be produced in any of a number of ways. Some of these ways are generally described as follows:

a) the inert mineral carrier is first contacted with a solution of an effective amount of oxamyl. Then, the solvent is removed and the carrier is contacted with an aqueous dispersion of the protective material. Thereafter, the fluffed medium is removed and granules of β are obtained by slow release of oxamyl. This process can be used to produce either type (1) or type (3) granules.

b) The inert mineral carrier is contacted with a single solution of an effective amount of oxamyl and a protective material. The liquid media is removed and slow release granules are obtained. Type 2 granules can be produced by this process.

c) Contacting the inert mineral carrier with a mixture of an effective amount of oxamyl, a polymerizable material, and a polymerization catalyst. The term polymerized material means a chemical unit or units that combine to form a protective material. The mixture of oxamyl, polymerizable material and polymerization catalyst may be in solution or in aqueous dispersion, but when the mixture of polymerizable material and catalyst is itself liquid, no additional liquid medium is required. After polymerization of the polymeric material, optionally the liquid media is removed to obtain oxamyl granules. Type 2 granules can be produced by this process.

d) The inert mineral carrier is contacted with a solution of an effective amount of oxamyl and then the liquid medium is removed. The carrier is then contacted with a mixture of polymerizable material and a polymerization catalyst, optionally in solution or in aqueous dispersion. By polymerizing the polymerizable material and optionally removing the liquid medium, type (1) or type (3) granules are obtained.

e) The inert mineral carrier is contacted with a solution of an effective amount of oxamyl and the liquid medium is then removed. The carrier is then brought into contact with the molten protective material. By cooling, which should be carried out rapidly to prevent oxamyl decomposition, type (1) granules are obtained.

f) Contacting the inert mineral carrier with a mixture of molten protective material and an effective amount of oxamyl. On cooling, granules of type / 2 are obtained.

The best process to use for making the granules will depend on the properties of the protective material used and will be apparent to those skilled in the art. For example, polystyrenes melt at temperatures above the decomposition temperature of oxamyl (110 ° C) and thus cannot be used as a melt. Granules containing polystyrene or styrene copolymer as a protective material are preferably produced by the process of e) or b) using an organic solvent.

Granules containing an unsaturated polyester-styrene copolymer or urea-formaldehyde protective material are preferably produced by the process of c) or d). The urea-formeldehyde systems are added to the carrier in an aqueous dispersion; The polymerization catalyst is any water-soluble acidic material. Such catalysts are known in the art and include citric, oxalic, sulfuric, phosphoric and toluene sulfonic acid. The unsaturated polyeeter-styrene systems are liquid, so there is no need to add an additional liquid medium to the protective composition to produce the granules. Suitable catalysts for this system include peroxide catalysts such as methyl ethyl ketone hydroperoxide and dimethyl phthalate.

The granules containing the vinylidene chloride copolymer as a protective carrier are preferably produced by the method of a) or b). These polymers are usually sold as aqueous dispersions and can be applied as such to the granules.

Finally, granules with wax, petroleum or polyolefin protective materials can be produced according to processes a), b), e) or f). The protective material can be applied as a melt, as in processes e) or f) if it has a sufficiently low melting point. When methods e) or f) are used, it is preferred that the protective material is free flowing at a temperature below 130 ° C. When method a) or b) is used, the wax or polyolefin or mixtures thereof are applied to the granules as a solution.

In processes a) to c), the oxamyl and / or protective material can be contacted with the carrier in the form of an aqueous dispersion or in solution. In the case of a solution, it is preferred that the solvent be volatile, that is, it can be removed at room temperature or at most about 80 ° C, or at any temperature below the decomposition temperature of oxamyl.

Suitable oxamyl solvents to be used in processes a), d) and e) include water, acetone, methanol or mixtures thereof and halogenated alkanes. Preferred halogenated alkanes are compounds wherein the alkyl group has about one or 2 carbon atoms and the halogen is chlorine. They exemplify methylene chloride.

Suitable solvents or dispersants for the protective material in process a) and the polymerizable material in process d) are known to those skilled in the art. If granules of type (1) are produced, the solvent or dispersant medium for the polymer in the polymerizable material should be a pure oxamyl solvent. An example of such a solvent is toluene. In contrast, if type (3) granules are to be prepared, the solvent or dispersing medium for the polymer from the polymerizable material should be such that it dissolves the oxamyl. Water (as a dispersant) and halogenated alkanes, especially methylene chloride (as a solvent) correspond to this description. Also suitable in this latter medium would be a mixture of solvents, for example methylene chloride and toluene.

In processes b) and c), the solvent or solvent mixture must be selected such that both the oxamyl and the polymer, or the polymerizable material and the catalyst are soluble. Again preferred solvents are halogenated alkanes, especially methylene chloride.

Those skilled in the art will know how to carry out the steps described as methods a) to f). A preferred method for contacting the carrier with oxamyl or a mixture of oxamyl and a protective material comprises spraying a solution, an aqueous dispersion or a melt onto the granules that are mechanically mixed in a belt mixer or rotary mixer. In another embodiment, the aqueous dispersion solution or melt can be applied to granules that are agitated in an air stream using conventional fluld box equipment.

The following examples illustrate various methods of making the compositions of the invention. All parts are by weight. The products of Examples 1-9 have a slowed release rate, as shown by the release of 60-80% oxamyl in 4.0 hours in water at 20 ° C. The products of Examples 9-13 have a release rate considerably slower, below 25% under the same conditions. A slower release rate affects a longer residual effect under the conditions.

He did

A solution of 0.12 g of oxamyl and 2.0 g of polystyrene (Shell 314-Net.) In 15 ml of methylene chloride is added simultaneously to 10.0 g of Celatom® MP-78 mineral granules. The granules are mixed by hand under a nitrogen stream until sufficient drying is achieved so that the granules can flow freely. The resulting granules are then air dried overnight. The product contains 1% oxamyl and 16% polymer.

Example 2

The procedure of Example 1 was repeated using 1.55 g of oxamyl and 4.0 g of polystyrene dissolved in 15 ml of methylene chloride. The product contains 10% oxamyl and 26% polymer.

Example 3

A solution of 1.55 g of oxamyl, 3.46 g of urea and 6.92 g of 37% aqueous formaldehyde is prepared. The resulting solution is treated with 0.1 g of 85% aqueous phosphoric acid as the polymerization catalyst and 8.0 g of Celatom MP-78 are immediately added. The mixture was stirred and the resulting product air dried overnight. The granules contain 10% oxamyl and 38% polymer.

Example 4

A solution of 25 g of oxamyl in 100 ml of hot water is gradually added to 161.2 g of Florex LVM 24/48 granulate, with mechanical mixing. The product is dried overnight. This granular material contains 13.4% oxamyl and is coated with various polymers as described in Examples 5-7.

Example 5 g of the granules of Example 4 were coated with 9.1 g of 5% polystyrene in toluene as described in Example 1. The product was air dried overnight and contained 12.8% oxamyl and 4.4% polymer.

Example 6 g of the granules of Example 4 were coated with 5.0 g of a urea-formaldehyde prepolymer solution prepared by treating a solution of 60 g of 37% aqueous formaldehyde, 7.0 g of triethanolamine β 15 g of urea, with 20 g of 85% aqueous phosphoric acid. The granules are air dried overnight and have been found to contain 11.8% oxamyl and 11.5% polymer.

Example 7

The procedure of Example 4 was repeated using 25 g of oxamyl in 100 ml of methylene chloride and 161.2 g of Celatom MP-78 granules. After drying the product overnight in air, treatment with a solution of 169.4 g of 5% polystyrene in toluene is carried out within one hour. The coated product is air dried overnight and contains 12.8% oxamyl and 4.35% polystyrene coating.

Example 8

A portion of 6.5 grams of dispense L® (liquid oxamyl formulations available from E.I. du Pont de Nemours and Company, Wilmington, Delaware) was added to 10.0 grams of Celatom MP-78 granules. The granule product is air dried overnight and then contacted with 3.99 g of a catalysed styrene mixture with unsaturated polyester (United States Steel MR-12190) containing 0.1 g of freshly added methyl ethyl ketone hydroperoxide in dimethyl caltalate (Witcro Quiokset catalyst). The mixture was maintained at room temperature and under nitrogen to complete the polymerization overnight. The product contains 10% oxamyl and 25.6% polymer.

Example 9

Add 249 g of dispensing L ® to 300 g of Celatom MP-78 granulate and then evaporate the solution on a rotary evaporator. A portion of 399 g of an aqueous vinylidene chloride copolymer latex (Beran 220 ® from W. R. Grece Co.) was then added dropwise to the granulate in an air stream using a rotary drum. After drying in an air stream, the product contains 10% oxamyl and 39% vinylidene chloride copolymer.

Example 10

2.0 g oxamyl treated SOelatom MP-78 granule granules as in Example 8 were contacted with a solution of 0.5 g Qulfwax® paraffin wax (Qulf Oil Co.) in 2.0 mL n-hexane. The granule product is dried in an air stream and contains 10.8% oxamyl and 20% paraffin wax.

Example 11

10.0 g of Florex LVU® 8 to 16 mesh granules containing 14.5% oxemyl (prepared with Vyta L® coating and loosening) were melted with 2.66 g of Gulfwax ® paraffin wax and 1.33 g of ethylene-vinyl acetate copolymers (Elvax) ® 210) containing about 28% vinyl acetate. The granule product contains 10.4 St oxamyl and 28 St polymer.

Example 12

10.0 g of Florex LVU® 8 to 16 mesh attepulgite granules containing 12.7 St oxamyl (prepared with Vyate L ® coating) are coated with a solution of 2.0 g of Qulfwax® paraffin wax and 0.5 g of low molecular weight epolene oxidized polyethylene ® E - 10 with 4.0 g oyklo hexane. The granules are then dried overnight in a stream of air. The product contains 10.2 St oxamyl and 20 St protective material.

Example 13

10.0 g of exemyl-containing Florex granules used in Example 12 are heated to 75 ° C and melt coated with 2.63 g of Qulfwax® paraffin wax and 0.87 g of oxidized polyethylene Epolene ® E-10. After cooling to room temperature, the granular product contains 9.4 St oxamyl and 26 St Protective Material.

Use

The granules of the invention are mixed into soil infested with Meloidogyne incognita.

After four weeks, complete control of the nematode was determined on all treated soil. The soil is contaminated with opSt and the comparative subtraction is performed two weeks later. The same tests were carried out using controls of technical oxamyl. The improved residual hassle suppression exhibited by the granules of the invention was observed for a total of eight weeks, as shown in the following table.

In tests carried out at different times, as in Test 1 and Test II, there are some deviations in the suppressive effect of the two tests. Therefore, the performance of the mS1 controlled release granules was evaluated when compared to the control granules used in the same assay.

In a separate test to assess the early performance of the granules of Example 1, the suppression of the pellet was evaluated only after two weeks, compared to the control, only at a dose of 0.25 g / ha. The product of Example 1 and the control embodiment are substantially equal, i.e. suppressing over 95 S.

Table

Percent suppression of héSétke Melioidogyne incognita *)

Description of the granule: Dose kg / ha 4 Weekly residual values (% of control) 6 8 10 Examination I control 5 100 ALIGN! 70 50 0 3 100 ALIGN! 50 0 0 Example 1 5 100 ALIGN! 100 ALIGN! 100 ALIGN! 50 3 100 ALIGN! 90 80 0 Example 2 5 100 ALIGN! 100 ALIGN! 85 50 3 100 ALIGN! 100 ALIGN! 70 0 Test 11 control 5 100 ALIGN! 0 0 3 100 ALIGN! 0 0 Example 3 5 100 ALIGN! 90 50 3 100 ALIGN! 50 0

% effective basis

Claims (3)

SUBJECT OF THE INVENTION Insecticidal or neoatocidal granules, characterized in that they are composed of an inert carrier in conjunction with methyl-2- (diraethylamino) -N- (methyleminocarbonyl) oxy-β-2-oxoethenothiothioethane as active substance and a protective material obtained from groups comprising polystyrene, styrene copolymers containing up to 5% by weight of comonomer, polymerized unsaturated polyester / styrene, urea-formaldehyde resins, copolymers of vinylidene chloride containing up to 10% by weight of comonomer, petroleum waxes such as paraffin wax, optionally mixed with up to 50% by weight of a modifier selected of low molecular weight polyethylenes, ethylene / vinyl acetate or polyetherpenes, polyolefins or mixtures thereof. 2. Granules according to claim 1, characterized in that the inert carrier is diatomaceous earth or attapulgite. 3. Granules according to claim 1, characterized in that the inert carrier is impregnated or coated with paraffin wax as a protective material, optionally in combination with up to 50% by weight of low molecular weight polyethylene as a modifier.