IE42919B1 - Solid pesticide compositions - Google Patents

Abstract

1516682 Pesticidal composition SOGEMARIC SOC DE GESTION ET DE MARKETING POUR INDUSTRIE DE CONSOMMATION 14 July 1975 [15 July 1974 6 June 1975] 29400/75 Heading A5E A phytosanitary composition suitable for agricultural application as a unit dose in the form of a solid, compacted body comprises at least one phytosanitary active-material and at least one solid, water-insoluble, and watersuspensible disintegrating agent having a polyhaloxide structure similar to that of starch. Wetting agents and fillers may also be added.

Description

This invention relates to a phytosanitary composition suitable for agricultural application as a unit dose.

More particularly, the invention relates to solid phytosanitary compositions for use in the treatment of amateur gardens by a new method which, so far as the user is concerned, eliminates the need for any complicated and/or dangerous handling of pesticides.

The treatment of trees, vegetables or flowers growing in amateur gardens involves specific problems due to a certain level of ignorance among amateur gardeners of the potential dangers presented by phytosanitary products.

The plants treated, in respect of which it is essential to keep to the stipulated doses on account of the phytotoxity phenomena to which excessive doses can give rise, are the primary concern because, very often, the amateur gardener has a tendency to increase the dose in the hope of obtaining a better effect whereas, in fact, increased doses can cause irreparable damage to the plants.

Another disadvantage of overdosage is the release into the atmosphere of excessive quantities of pesticides which are incompatible with protection of the environment and also contrary to legislation on the use of pesticides.

Another danger, this time involving the user, is the need for difficult manipulation of small quantities of more or less toxic products which very 'often are in the form of extremely fine powders which are readily blown away by wind and, for this reason, are difficult and, in some cases, dangerous to handle.

Accordingly, for these three reasons it is extremely important to develop and make available to amateur gardeners formulations and devices which eliminate such disadvantages.

The present invention responds to this need by providing a formulation as a unit dose in the form of a solid compacted body.

This type of formulation eliminates the dangers of overdosage. In use, a unit dose of a particular size is disintegrated with a predetermined volume of water with which it is brought into contact. In other words, for satisfactory use the quantity of disintegrated material must be proportional to the volume of water used.

This effect is obtained by conventional means in the pharmaceutical industry in the form of tablets which are obtainable by the compression of a powder with various additives, especially binders. However, such tablets cannot be used for the application of pesticides to plants on account of the very small quantities of disintegrated matepial per litre of disintregating liquid, because the active material has to be applied to the plants in quantities sufficient to obtain the required effect. thus, the present invention provides a phytosanitary composition suitable for agricultural application as a unit dose in the form of a solid, compacted body comprising at least one phytosanitary active material as herein defined and at least one solid, water-insoluble and water-suspensible disintegrating agent having a polyholoside structure similar to that of starch.

Thus, the composition according to the present invention is intended to be progressively disintegrated by contact with a stream of water. In addition to the active phytosanitary material and the disintegrating agent the composition may also optionally comprise one or more wetting agents and/or dispersants of the type normally used in the production of wettable powders. If the wettable powder contains a solid filler, the filler used should not have hydrophilic properties.

In the context of the invention, a solid non-hydrophilic filler is a powder-form solid without any tendency to hydrate in aqueous medium, because in contaet with water a composition containing a hydrophilic filler gives a tacky paste which slows down disintegration to a considerable extent.

In the context of the invention, a phytosanitary active material means a herbicide, insecticide, fungicide, growth regulator, bactericide or fertiliser which may be applied to plants or seeds. According to the invention, the compositions may contain one or more active materials which, together, may represent a few % to 80% by weight of the composition.

In the context of the invention, the solid disintegrating agent should be insoluble in water which does not mean that it should not be hydratable or swellable in water. This is the case 43919 with starches1, based on such vegetables as corn, rice, potatoes, which give good results, although maize starch is preferred. The disintegrating agent must also be watersuspensible and have a polyholoside structure similar to that of starch.

The disintegrating agent must be present in a sufficient quantity to ensure that the rate of disintegration, i.e. the quantity of solid active material disintegrated per litre of water, is high enough to eriable the plants to be effectively treated.

By contrast, an excess of this additive causes excessively rapid disintegration. Generally, quantities of from 20 to 60% by weight of the composition are perfectly suitable. However, this is by no means limitative and quantities outside these limits may be used provided that an adequate rate of disintegration, for example approximately 2 to 15 g/1, is obtained.

In order to prepare the compositions according to the invention, a mixture of one or more active phytosanitary materials (herbicides, growth regulators, insecticides, fungicides) in solid form, i.e. either the active material alone if it is solid, or impregnated on a solid, inert support it if is liquid, is mixed with the additives, wetting agents, dispersants of the type commonly used in the production of wettable powders, and with the non-hydrophilic filler and the disintegrating agent described above. The mixture is homogenised and then compressed into tablets or pellets of the required shape under a pressure in the range from 50 to 1000 kg/cm and preferably under a pressure in the range from 100 to 600 kg/cm . 3919 The compositions according to the invention are preferably prepared in two stages: in the first stage, the active materials additives and fillers are mixed, optionally with grinding or micronisation, and in the second stage the premix thus obtained is in turn mixed with the disintegrating agent in the absence of any grinding effect. In this way, the shape of the starch grains is not altered by deformation or fragmentation which, as illustrated in the following Examples, considerably improves the concentration of active material in the sprayed liquid and the uniformity‘of the disintegration rate.

The compact· compositions according to the invention may be used in the form of a cartridge in appliances of, for example, the long-barrel spray gun type used by amateur gardeners comprising a mixing device in which the stream of water comes into contact with the suitably shaped surface of the composition during the compression stroke.

Devices of this type may vary according to whether the compact composition or cartridge has a variable or constant disintegration surface.

One example of a device of the first type is the device described in German Patent Specification No. 1,211,603, whilst the device described in Patent Specification No. 41779 is an example of the second type of device.

The followihg Examples illustrate the compositions according to the invention and the process for their preparati on. 429X9 Example 1 An insecticide mixture with the following composition (by weight) was prepared: · i i Malathion: S-(l,2-di- ethoxycarbonyl -ethyl)-dimethylphosphorothiolothionate 15% Lindane (γ-isomer of hexachlorocyclohexane) 4% maize starch 30% talcum 24.5% kaolin 4% Absorbent silica 13% naphthalene sulphonate (wetting agent) 3.2% condensate of 10 molecules of ethylene oxide with nonyl phenol (wetting agent) 0.3% calcium lignosulphate (deflocculant) 3% sodium isopropyl naphthalene sulphonate (dispersant) 3% The malathion, being liquid', was first applied by impregnation to the silica. The mixture of active materials, starch and additives was homogenised for 30 minutes in a paddle mixer and then compressed under a pressure of 125 bars into cylindrical pellets weighing approximately 10 g. Five of these pellets were successively introduced into the magazine of a mixing device connected to a spray nozzle of the type described in Patent Specification No. 41779 in which pesticide cartridge has a constant disintegration surface. The device was connected to the running water supply, and then fractions of 500 ml were sprayed into a graduated vessel.

The test was repeated three times, which substantially corresponded to exhaustion of the cartridge. The contents of each vessel were evaporated and the dry extract weighed.

The following results were obtained in this way, representing an average value based on the five cartridge.

Volume of water collected (ml) Weight of solid material collected (g) Ratio of weight to volume (disintegration rate in g/l 500 2.7 5.40 1000 5.3 5.30 1500 8.2 5.45 2000 10.5 5.25 This table shows, on the one hand, the high level of uniformity of the quantity of solid material disintegrated per volume of water.and, on the other hand, that the disintegration rate amounts to between 5 and 5.5 g/l.

Example 2 A fungicide mixture with the following composition (by weight) was prepared: dicofol (2,2,2-trichloro-l,1 di-(4-chlorophenyl)-ethanol) 12% rice starch 30% talcum 42% sodium naphthalene sulphonate 2% potassium isopropyl naphthalene sulphonate 3% kaolin 3% absorbent silica 8% The mixture was homogenised, compressed and tested in the same way as in the preceding Example. The results obtained are set out in the following Table: Volume of water collected (ml) weight of solid material collected (9) Ratio of weight to volume (disintegration rate in g/l 500 1.9 3.8 1000 3.4 3.4 1500 5.6 3.7 2000 7.8 3.9 In this case, the quantity of material disintegrated amounted to from 3.5 to 4 g/l, disintegration took place with a high level of uniformity.

Example 3 A fungicide mixture with the following composition (by weight) was prepared: maneb (manganese ethylene-1,2-bis- dithioearbamate) 47% benomyl (methyl-N-(1-n-butyl carbamoyl-2-benzimidazole)carbamate 6%. potato starch i'JZ glucose 5% isopropyl naphthalene sulphonate 2% naphthalene sulphonate 1% The mixture was homogenised and then compressed under a pressure of 165 bars. The pellets obtained were then tested in the same way as in Example 1. The results obtained are set out in the following Table: Volume of water collected (ml) Weight of solid material collected (g) Ratio of weight to volume (disintegration rate in g/l) 500 2.6 5.2 1000 5.5 5.5 1500 8.3 5.55 2000 10.8 5.4 This Table shows that the disintegration rate amounts to around 5.3 g/l with a high level of uniformity.

Example 4 The influence of grinding upon the disintegration rate is illustrated by the following test: Three separate fungicide formulations with the following common composition (by weight) were prepared: maneb (manganese-ethylene-bis-dithiocarbamate), 85% commercial grade 23.5 triturated sulphur 30.0 maize starch 21.5 talcum 25 These formulations, designated Fp Fg and Fg were prepared in two stages, the first stage being common and comprising mixing the maneb, the sulphur and the talcum in a blade mixer. In a second stage the premix was in turn mixed for 30 minutes with maize starch. 429 19 in a microniser in the case of F-j (95% of the particles smaller than 10 microns), in an Alpine type mill in the case of F2 (95% of the particles smaller than 50 microns), in a simple paddle mixer in the case of Fg (particle size 0 not reduced).

Each of these compositions was then converted under a pressure of 487 bars into compact cylindrical cartridges 28 mm in diameter each weighing 20 grams.

These cartridges were then covered by thermoforming in vacuo with an 80 microns thick polyethylene film and introduced into a spray gun for amateur gardeners of the type described in Patent Specification No. 41779, in such a way that the disintegration surface was constant. The spray gun was connected to a water supply under a pressure of 3 bars so as to obtain a throughput of about 0.4 to 0.5 1itre/minute. The water inlet was opened by means of a trigger so that the cartridge was disintegrated and the disintegrated substance sprayed in the form of a fine mist. The average volume required to exhaust the cartridge and the standard deviation in litres for a series of tests were then determined, each figure being the average of 8 tests.

The results are set out in the following Table: Formulation Mean volume litres Standard deviation (litres) Throughput (1/minute)F1 4.32 0.44 0.42F2 2.87 0.38 0.44F3 2.07 0.20 0,44 as 19 This table clearly shows that, at a constant throughput, formulation Fg containing micronised starch requires a disintegration volume more than 1.5 times greater than that required for formulation Fg and more than twice that required for formulation Fg. In other words, for the same coniposition, formulation Fg enables twice the quantity of active material to be applied to the plant which is of particular advantage for gardening formulations which, since they are often of a multipurpose character, have to contain more active material.

In addition, notation of the standard deviation shows that the reduction and, a fortiori, the absence of a grinding effect during mixing of the starch with the premix of active materials considerably improves the uniformity of disintegration.

These results show that, according to the invention, it is important that the starch grains should not be fragmented by grinding. Accordingly, the apparatus used for mixing the active materials and starch must be able to carry out this operation without altering the shape and size of the grains.

Similar results were obtained with the following compositions: Example 5 Combined insecticide/fungicide coniposition 85% commercial grade maneb 23.5 Triturated sulphur 30.0 commercial-grade 5-(6-chloro-2-oxobenzoxazolin-3-yl)-methyl diethyl phosphorothiolothionate (phosalone) 6.0 talcum 12.5 maize starch , 28.0 100.0 mean volume : 1.99 1, standard deviation: 0.14 1 2919 Example 6 Insecticide composition — ....... t——-commercial grade phosalone 6.0 absorbent synthetic silica 6.0 kaolin coloured by methylene glue 3.0 talcum 35.0 rice starch 50.0 100.0 mean volume: 2.06 1, standard deviation: 0.15 1 Example 7 Fungicide composition 83% commercial-grade 2,2,2-trichloro-l,1 -di15 (4-chlorophenyl)-ethanol (dicofol) 5.9 absorbent synthetic silica 4.1 kaolin coloured with methylene blue 32.0 maize starch 55.0 100.0 mean volume: 1.92 1, standard deviation: 0.12 1 Example 8 Combi ned insecticide /fungicide composition γ-isomer of hexachlorocyclohexane (lindane), « , 95% commercial grade 85% commercial-grade methyl-1-naphthyl carbamate (carbaryl) 8.9 zinc ethylene-1,2-bis-dithiocarbamate (zineb), 93% 21.5 triturated sulphur 30.0 talcum 10.0 potato starch 27.3 100.0 mean volume: 2.05 1, standard deviation: 0.091 4291® Example 9 Fungicide composition for vine copper oxychloride containing 53% of copper metal 93% commercial-grade zineb 85% commercial-grade maneb talcum corn starch mean volume: 3.80 1, standard deviation: 0.15 1 In this case, the cartridges weigh 40 grams but are otherwise identical.

Example 10 Selective herbicide for the treatment of grass 28.0 .4 .9 .0 50,7 100.0 sodium salt of 2,4-dichlorophen0xy acetic acid (2,4-D) 5.5 sodium salt of 2-methyl-4-chlorophenoxy propionic acid 22.0 maize starch 41.0 talcum 31.5 100.0 A 40g cartridge disintegrating into 4 litres enables 40 square meters of grass to be treated. mean disintegration volume: 3.90 1, standard deviation: 0.21.

Example 11 Selective herbicide for the treatment of grass Sodium salt of 2,4-dichlorophenoxy acetic acid kaolin talcum maize starch A 20g cartridge disintegrating into 2 litres enables 20 square metres of grass to be treated.

Average disintegration volume: 2.06 1, standard deviation: 0.01 1 11.0 3.0 .5 50.0 100.0 42918 Example 12 Fertiliser for leaf application diammonium phosphate 4.05 urea 2.10 potassium nitrate 3.67 oligoelements (B, Cu, Fe, Mg, Mn, Mo, Zn) 0.18 starch 20.0 talcum 70.0 100.0 A 20g cartridge disintegrates on average into 2.15 litres io with a standard deviation of 0.2 1.

These Examples are intended to illustrate insecticide and/or fungicide or herbicide composition, although compositions with a growthregulating effect on plants and, in addition, the same properties as the compositions described also form part of the invention.

The compositions of Examples 5 to 12 do not contain any wetting agent and/or dispersant and/or flocculant, because experience has shown that these additives are not indispensable and are only useful when the active material is extremely hydrophobic.

These Examples illustrate the remarkable properties of the compositions according to the invention, namely their ability to disintegrate uniformly at an adequate disintegration rate.

These compositions may thus be used with a variety of phytosanitary active materials for the treatment of cultures of all kinds, more especially trees, vegetables and flowers.

This application, combining simplicity, convenience and safety both for the user and for the plant, makes the compositions particularly suitable for the treatment of amateur gardens.

Claims (15)

1. C L A I (4 S

1. A phytosanitary composition suitable for agricultural application as a unit dose in the form of a solid, compacted body comprising at least one phytosanitary active material as herein defined and at least one solid, water-insoluble and watersuspensible disintegrating agent having a polyholoside structure similar to that of starch.

2. A phytosanitary composition as claimed in claim 1, which comprises at least one filler which is not hydrophilic.

3. A phytosanitary composition as claimed in claim 1 or 2, which comprises one or more wetting agents, dispersants or deflocculants.

4. A phytosanitary composition as claimed in claims 1 to 3, wherein the disintegrating agent is starch.

5. A phytosanitary composition as claimed in claim 4, wherein the starch is not ground.

6. A phytosanitary composition as claimed in claim 4 or 5, wherein the disintegrating agent is maize starch.

7. A phytosanitary composition as claimed in any of claims 1 to 6, wherein the disintegrating agent is present in a quantity of from 20% to 60% by weight based on the total composition.

8. A process for the preparation of a phytosanitary composition as claimed in any of claims 1 to 7, comprising drymixing at least one phytosanitary active material as herein defined optionally with at least one non-hydrophilic filler and, optionally, at least one surfactant of the type normally used in the production of wettable powders, introducing at least one solid, water-insoluble and water-suspensible disintegrating agent having a polyholoside structure similar to that of starch and compressing 4 2 919 the resulting mixture into unit doses under a pressure of from 50 to 1000 bars.

9. A process as claimed in claim 8, wherein the disintegrating agent is a starch.

10. A process as claimed in claim 8 or 9, wherein the pressure applied is in the range from 100 to 600 bars.

11. A process for the preparation of a phytosanitary composition as claimed in any of claims 8 to 10, wherein, in a first stage, at least one phytosanitary active material as herein defined is mixed, optionally ground or micronised, optionally with at least one filler and, optionally, with a surfactant and, in a second stage, the resulting mixture is itself mixed with starch in the absence of grinding.

12. A phytosanitary composition substantially as herein described with reference to any of the specific Examples.

13. A process for the preparation of a phytosanitary composition substantially as herein described with reference to any of the specific Examples 1 to 4.

14. A phytosanitary composition when prepared by a process claimed in any of claims 8 to 11 and 13,

15. A method of treating plants or seeds which comprises contacting a phytosanitary composition as claimed in any of claims 1 to 7, 12 and 14 with a predetermined volume of water in order to disintegrate the composition and appl the plants or seeds or to their environment.