DE2403427A1 - METHOD FOR MANUFACTURING PESTICIDES PREPARATIONS - Google Patents

Description

PATENT LAWYERS! DR.-ING. H. FINCKE 240342?

DIPL-ING. H. BOHR. !

DlPL-ING. S. STAEGER ^:

8 MUNICH 5 I.

MÜLLCRSTRASSE 31 j

Folder 23 ^ S / Dr.K. Jan 24

Case: PP.25 # 27 '

IMPERIAL CHEMICAL INDUSTRIES LIMiED London, United Kingdom

PROCESS FOR THE MANUFACTURING OF PESTICIDAL PREPARATIONS

Priority: January 29, 1973 - Great Britain - 4388 / 73i

The invention relates to pesticide preparations and in particular to pesticides which are prepared in a particularly suitable form for rapid dispersion in water. In particular, the invention relates to water-insoluble Pesticide made in the form of dispersible granules, and to a method for the preparation of Prep pesficiden> .ira ^J th in the form of dispersible granules relates.

One of the main difficulties encountered in. The pesticide industry ' there lies in the conversion of water-insoluble pesticides into normal preparations, which are easily dispersed in water result. Preparations in the form of dispersible powders are known, but they are not particularly convenient in use and can even be dangerous both in use and in manufacture in certain cases. Powdery Preparations are voluminous and not always easy and safe to use pack. As a result, attempts are being made to produce pesticide preparations in the form of granular products, which in some cases

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The extent to which the disadvantages associated with powders are avoided. Granular preparations are of particular value if, in the ^{course of the} production of a powdery preparation, a material or substance occurs which is dangerous to handle in this way ^;

Numerous processes for the production of ν cn granules have already been developed. These will be the most diverse uses known techniques such as sludge and spray drying of a wet mix, which contains the pesticide and other ingredients. Nevertheless, this method often has to be ground and / or can be pelletized.

A particularly convenient and inexpensive method has now been found. The process allows manufacture of water-dispersible grains, which are solid, free-flowing preparations, do not generate dust and are quickly wetted by water and can be dispersed therein at a high speed. The content of pesticide '(active ingredient) can be high in case of need, and also has the Product has a high bulk density.

According to the invention, a process is now proposed for the production of water-dispersible grains with a particle size range of 0.5 to 5 mm, which contain at least 15% by weight of a solid, water-insoluble pesticide and at least 4% by weight of a dispersant, wherein the process is carried out by preparing an extrudable aqueous mixture of the water-insoluble pesticide, the dispersant and eäaem D. ^e sintegrierungsmittel, the pesticid largely'the form of particles with a diameter of less

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than 200 u *, the mixture is extruded to form moist cohesive granules, the granules are dried and, if necessary by sieving, granules with a particle size in the range vöb. ^% Ö, 5 "to 5 mm wins.

The term "water-insoluble" here means a soluble. ness in the V / ater at 2O ⁰ C of not more than 1 wt .-%.

Often the pesticide to be processed in the method according to the invention is in the form of a press paste or a Filter cakes that contain a proportion of water are available. It is preferred, in addition to the dispersant, too incorporate a wetting agent into the mixture. The usual fillers can also be incorporated into the mixture, which also applies to other components, for example water-soluble pesticides, such as herbicidal bipyridilium salts, is applicable.

The aqueous mixture is suitably mixed in a ribbon mixer or in a similar mixer. A preferred one Extruder shape for carrying out this extrusion stage is one in which further mixing takes place in the extruder head. . '"

The free moisture content of the mixture is set so. that the extruded mixture emerges from the extruder in a crumbly form. This setting or Selection of the "free" moisture content is essential for the invention Procedure essential. If the mixture is too wet, the extrudate will come out of the extrusion die as a continuous ribbon (like a spaghetti) and does not break into granules of the desired size. If that

4 0 9 8 31/10 7 3

If the mixture is too dry, the extrudate will not form any cohesive granules and breaks into dust during the drying stage. If the mixture is too dry this can be corrected simply by adding water or an aqueous solution. if But if it is too wet, then you have to partially dry it - by conventional measures, such as moderate watering. heat and by a vacuum treatment or preferably by mixing with a water deficiency containing salt. After "drying it may be necessary or." it may be desirable to sift the grains to obtain fine material that may have formed during the procedure.

The term "dispersant" is used herein for a surfactant Agent used which facilitates the dispersion of the pesticidal particles when the product placed in a liquid such as water wM. The dispersants used are preferred water soluble. Examples are lignosulfonate salts, such as Polyfon H, and condensation products of formaldehyde with sulfonated, unsubstituted. or substituted Phenol, aniline or a corresponding naphthalene derivative thereof and optionally with urea. Examples of such Condensation products are Dispersol T and Dyapol PT.

The wetting agent is a surface-active agent which facilitates wetting of the dispersible granules in water. Are wetting agents that can be used in the method and preparations of the invention

and Arvlan ^b % i ^ ^{: for example} ^^ yü ⁸¹ "* ⁶ benzenesulfonate salts, such as, for example, ^Ar> y ^{lan S} « ^B ethylene oxide condensates with aliphatic alcohols, amino acids or alkylphenols, such as, for example, Lissapol NX, in which

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Nonylphehol is included '; and alkylnaphthalene ^sulfonates: such as Perminal BX. ■

All surfactants work to some extent
as a dispersant and to a certain extent also as a wetting agent

middle. The ma. Most surface-active agents are, however!

unacceptable with regard to one or the other property;

reaching. One in the manufacture of corresponding preparations;

experienced technician can easily do this for a particular '<

Select the most suitable surfactants for the purpose. , '

With the term "disintegrant" there is one
solid, easily water-soluble substance meant, such as
a salt or a simple organic substance, which: 'support the disintegration of the dispersible grains ] when these are introduced into water in order to produce the dispersion. "Because of their easy solubility or because of a reaction when they come into contact with the liquid, they help break up the grains. Substances that can be used as disintegrants are, for example, sodium acetate,
Sodium sulfate, sodium bicarbonate and citric acid. Mixtures of disintegrants are often expediently used.

The expression "SoIz with water deficit" is a salt
meant which is to absorb water of crystallization
is able to determine the amount of free moisture present
to lower the mixture to a value at which the mixture
shows a satisfactory extrusion behavior. Suitable

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Salts with an excess of water are, for example, sodium acetate and sodium sulfate and magnesium sulfate. If so desired can use the same salt in the extrusion mix as both a disintegrant as well as salt> with water deficit ' serve, i.e. that it takes over a double puncture.

The particle size of the pesticide used is below 200 and generally the preferred particle size from 5 to 50 u, but can be larger or smaller Particle be satisfied. The press paste of the pesticide often contains between 10 and 50% by weight of water.

The term “pesticide” here means any chemical pesticide, such as an insecticide, an acaricide, a molluscicide, a herbicide, a plant growth modifier, a plant fungicide, a plant bactericide and a plant antiviral agent Invention have been processed into dispersible granular preparations are listed below. ■ ^;

The invention is not limited to the following pesticides. These pesticides are for illustrative purposes only. - · · -

Common name . Chemical name

Gaptan. N- (Trichloromethylthio) cyclohex-

4-en-1,2-dicarboximide

Ca £ tafol N- (1,1,2,2-Tetrachlo ^ ithylthio) -

cyclohex-4-en -1,2-dicarboximide

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- ι -

Common name . GHEMSCHER NAKE

Drazoxoi'on · 4- (2-Chlorophenylhydrazone Q.) - 3-

methyl-5-isoxazolone

Iletazoxolone. '' 4- (3 * -Chloroplienylliydraziiio-3-

methyl-5-isoxazolone

Ethirimol. 2-ethylamino-4-methyl-5-n-butyl-

6-hydroxypyrimidine

Pirimicarb 2-Dimethylamino-5 »6-dimethyl-

pyrimidin-4-yl diethyl carbamate

Simazine '2-chloro-4,6-bis (ethylamino) -1,

3,5-triazine ..

Other water-insoluble pesticides caused by the .invention according to the invention The process can be processed into preparations in "Pesticide Manual" by H. Martin, 3rd edition by the British Crop Protection Council.

The free moisture content or degree of moisture the extrudable aqueous mixture depends on a number on factors such as the nature of the one used Pesticids and their proportion in the mixture; on the particle size of the pesticide; and on the general rheological Properties of the mixture. However, the free moisture content of the extrudable aqueous mixture will generally be within the range between 5 and 25% by weight.

The equipment used to make the mixture can be for example from a ribbon mixer or from a mixer

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with a staggered spiral exist, for example under the name "Winkworth-Mischer" land "Gardener-Miseher" are known. Planetary mixers such as the "Nauta mixer" can also be used.

In general, any extruder can be used to perform the extrusion stage in the process according to the invention "is used will. Particularly useful extruders are the "Elanco extruders". A very particularly preferred extruder for small scale manufacture is the "Elanco Model XDC 100 extruder". It is preferred that the extrusions Openings, which are the holes through which the mixture is pressed, are present in a sieve, which has a hole size between 0.55 and 1.2 mm, although fairly larger holes too, used if necessary can be. In operation, the mixture is fed into the machine and through the rotating screw brewed into an extrusion chamber, the walls of which with a sieve of the hole size described is provided. The extrusion speed can be within wide limits vary. For example, for an "Elanco Extruder • Model 100 2DC", a suitable speed is 35 kg to 35 kg 120 kg extrudate per hour

The drying of the crumbly extrudate can be carried out with any known drying device. If necessary the extrudate can be dried simply by letting it stand. Accelerated drying is however more expedient. It is preferred to use a fluid bed dryer to use. A suitable fluid bed dryer is an example the Manesty-Petrie dryer model MP1OOS.

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Such drying is preferably carried out by reacting, "the temperature of the extrudate increases, for example, half an hour at 60 ⁰ G (shorter times and higher temperatures and vice versa can also be used). If a seven is necessary for the removal of fine material Then any sieve with a suitable plate size can be used. The sieve is preferably vibrated by mechanical action. A suitable sieve is, for example, one with a plate size of 0.5 to 2.0 mm to pass mechanically vibrated sieve with a diameter of 2.0 mm, discard the coarse grains remaining on the sieve and then pass the grains that have passed through the sieve through a mechanically vibrated sieve with a diameter of 0.5 mm, discard the grains and fines that have passed through and as finished product which is placed on the sieve with a size of 0.5 mm Use leftover grains. The discarded coarse and fine plating material can be returned and added to the next injection point for extrusion.

The invention is illustrated by the following examples.

EXAMPLE 1 '-' ·

This's example explains the production of a disposable Grain preparation containing the pesticide with the common name Drazoxolone. This substance can through the the following chemical formula can be represented:

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2403425

- ίο - j

N-NH

The chemical name is 4 ~ (2-chlorophenylhydrazono) -3rinethyl-5-isoxazolone.

The "ingredients used in the preparation of the preparation are given below. The name or trade name of each ingredient is accompanied by a Mentioned its effect. The amounts used are also given. The drazoxolone was particle size in the range from 2.5 to 20 μ and was processed as an aqueous press paste (filter cake).

Amount used (grams)

Drazoxolone, aqueous press paste. (71.8% active ingredient, 75.5% Solids). · 8360

Polyfon H (dispersant) ■ 1500

Arylan SB (wetting agent) 100

Sodium bicarbonate 400

Sodium Acetate Anhydrous 372

GTY Powder (clay as a thinner) "1318.

The ingredients are in a Nauta mixer for 10 min long mixed. The press paste is introduced first, and

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ORIGINAL INSPECTED

then the sodium acetate and then the other ingredients are added. The moist powder mixture obtained

is extruded at a rate of approximately 90 kg / h through an "Elanco extruder * (model XDCS 100), where a sieve with a mesh size of 0.55 nm is used. The extrudate emerging from the sieve breaks up into moist, cohesive granules. The product is collected and in a fluid bed dryer with an inlet temperature

dried from 60 ⁰ G to a residual water content of 3.5%, which is determined by the Dean-Stark method. The product is then sieved. The fraction which passes through a 1.7 mm mesh screen and is retained by a 0.5 mm mesh screen is recovered. The fines passing through the latter sieve are discarded. The fines and the oversized grain can be added to the next batch. . j-

The product conforms to the following specification:

Disintegration and suspen-

controllability. "1.0 grams of product will be too

100 ml standard hard water

. · Added ("World Health

Authority Specification for Pesticides ", the second on location, 1961. (WHO, Geneva)), in a Crow. Receiver is changed sides after which the receiver 15 min. The receiver is placed in a Waseerbad with 30 ^0C.

After 2 min: the amount of sediment should be the highest be a trace.

After 5 min: the amount of sediment should not exceed 0.1 ml.

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after 30 min: the amount of sediment

should not exceed 0.3 ml.

After 30 min the suspension is through a Sieve with a mesh size of 0.12 mm and a diameter of 8.5 cm passed through it, and after washing with 1 water there should be no material on the sieve be more present.

Appearance:

Free flowing granular product

Moisture content

between 2.0 and 5.0 ί water according to Dean-Stark

Sieve analysis:

passes through a sieve with a mesh size of 1.7 mm, but becomes through a Retained sieve with a mesh size of 0.5 mm.

EXAMPLE 2

This example illustrates the production of a 50 kg batch

a dispersible granule preparation containing the paraquation and Contains simazine.

Paraquat concentrate (36.1 % cation) - 10, ¹ I 1

Simazine (technical purity) 15.0 kg

Cetyl trimethyl ammonium bromide 2.0 kg

Magnesium sulfate (anhydrous) 28.0 kg.

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The magnesium sulphate is introduced into a mixer, and the "paraquation" is in the form of a concentrated one Solution of paraquat dichloride added and mixed in. The simazine (with a mean particle size of 5 "u) and the surfactant are then added and mixed in. The mixture obtained is extruded, dried and sieved in the manner described in Example 1. The product corresponds to that given in Example 1 Specification.

EXAMPLE 3

This example describes the. Manufacture of a dispersible granule preparation, which is known under the common name Pirimicarb contains well-known pesticid.

The approach for a 4 kg batch is as follows:

Pirimicarb (aqueous press paste,

mean particle size so u,

78 % solids) 2.56 kg

Dyapol PT. 0.6 kg

Sodium acetate (anhydrous) ■ "0.4 kg blue _{opaque dye 0 r} 04- kg talc S2 · · 0.96 kg.

The ingredients are mixed together (first the active Ingredients and then the sodium acetate and finally the remaining ingredients) in a Nauta mixer.

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The mixture ready for extrusion contains 9.5 % free water. The mixture is then extruded as in Example 1 above at a rate of approximately 40 kg / h. The product is dried in a fluidized bed dryer with an inlet temperature of 60 ° C. until the residual water content is between 0.5 and 1 % . The product is then sieved through sieves with a mesh size of 2.0 or 0.5 mm, and the product is that fraction which passes through the sieve with a mesh size of 2 mm, but is retained by the sieve with a mesh size of 0.5 mm . The product conforms to the specification approached at the end of Example 1, except that:

a) 0.2 g of the product in the (test for disintegration and suspensibility can be used and the 5, min and 30 min sediment limits Are 0.05 ml and 0.1 ml, respectively; and;

b) the moisture content of the product is between 0.5 and 1 ⁰ Jo .

EXAMPLE 4

This example illustrates the preparation of a dispersible Grain preparation containing the pesticide metazoxolone.

The approach for a 25 kg batch is as follows:

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2.67 kg kg. 3.75 kg 0.25 • kg 2.5 kg 15.83

Metazoxolon (aqueous press paste, 94 % solids) Polyfon H Arylan SX Sodium acetate "(anhydrous)

GTY "Powder (clay as thinner smi 11 e1)

The metazoxolone (which has a mean particle size of 8 u) is mixed with the sodium acetate, and the other ingredients are then added to this mixture. The water content of the mixture is then determined by Addition of water adjusted to 20% by weight. The mixture is then extruded according to Example 1 and then in a fluidized bed dryer at an inlet temperature of 60 ° C up to a residual water content between 2 and 4% by weight dried.

The dried product is then sieved, with the part, which passes through a sieve with a mesh size of -1.7 mm ' but is retained by the sieve with a mesh size of 0.5 mm, is taken as a finished product.

The product corresponds to the specification given in Example 1, the limits determined in the disintegration and suspensibility test after 5 min and 30 min being 0.2 ml and 0.5 ml and the moisture content between 2.0 and "4, 0 % .

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EXAMPLE.

This example illustrates the preparation of a dispersible Grain preparation containing captan as a pesticide (active ingredient). The approach is as follows:

Captan (powder of technical purity!

mean particle size 5 JA J 2,500 g

"Polyfon" H 375 g

Sodium carbonate 875 g

"Arylan" SB 50 g

Sodium acetate (anhydrous) 205 g

Speston. . 1,200 g

Water · 'Λ 000 g.

Mixing of the above ingredients is carried out in a ribbon blender for 30 minutes. Then 1 liter of water is added and stirring is continued for a further 5 minutes. The mixture, which contains 13 »0% free water, is then extruded, foot dried and sieved as described in Example 1 above. According to an analysis, the product shows a captan content of 4-5 »0 % and contains no water. When it is placed in water, disintegration takes place rapidly, creating an aqueous suspension of the pesticide.

Some of the ingredients used in the preparations of the above examples are described in more detail below.

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Dyapol PT

(Supplier: YORKSHIRE DYEWARE) is probably a condensate of suIfanilic acid and formaldehyde and urea. It also contains sodium sulfate.

Talc S2

is a coarse talc, i.e. a complex, hydrated one Magnesium-alumino-silicate.

Polyfon H (supplier: WESTVACO, U.S.A.) Is sodium lignin sulfonate. . ·

Arylan SB
and

Ary-lan SX (LMerer: LAIiKRO CHEMICALS) are branched-chain (SX has more branches than S.B.) Dodecyl-benzene-sulfonic acids.

Spests

is a fine clay.

Herbicidal grains, which are mixtures of insoluble herbicides with herbicidal bipyridylium salts (e.g. halides) contain, can be processed into preparations according to the invention particularly expediently.

Grains that contain mixtures of paraquat and siamzine are explained in example 2. Similarly, grains can be made containing mixtures of salts of Diquat contain the insoluble herbicide diuron. AuJtodem can open In the same way grains are produced, the mixtures of '1,1' -bis (Π, Ν-diethylaminocarbonylmethyl) -4 ·, 4- '-bipyridylium salts with the insoluble herbicide atrazine.

As explained in the above examples, the

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Invention furthermore water-dispersible grains with a size in the range from 0.5 to 5 mm, which are at least "Ϊ5 % and generally not more than 80% by weight

a solid, water-insoluble pesticide in the form of particles with a size of less than 200 microns in diameter, a disintegrant, generally in amounts of 5 to 60% by weight, and at least 4%, but preferably contain no more than 25% by weight of a dispersant, a water content (measured by the Dean-Stark method)

of not more than 5 % and disperse in a 1% dilution in hard standard water at 30 ⁰ G in such a way that practically no sediment has formed after 2 minutes.

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Claims (6)

PATENT CLAIMS: (ϊ) process for the preparation of water-dispersible granules having a particle size in the gereich mm from 0.5 to 5 and at least 15 wt ^-%. of a solid, water-insoluble and at least Pestieids ^ weight 5S • a dispersing agent, characterized characterized in that "an extrudable aqueous mixture of the water-insoluble pesticide, the dispersant and a disintegrant is prepared, wherein the pesticide is largely in the form of particles with a size of less than 200 microns in diameter, the mixture is extruded to form moist cohesive granules, the granules dries, and granules with a particle size in the range from 0.5 to 5 are now obtained, if necessary by sieving. 2. The method according to claim 1, characterized in that the production of the extrudable aqueous mixture includes adjusting the free moisture content of the mixture by adding water. 3. The method according to claim 1, characterized in that the production of the extrudable aqueous mixture includes adjusting the free moisture content by adding a salt with an excess of water. 409831/1073 2403A27 4. The method according to claim 5, characterized in that that the salt with water deficiency is a disintegrant is. Process according to one of Claims 1 to 4, characterized in that the granules are stored in a fluidized bed dryer to be dried. 6. The method according to any one of claims 1 to 5? through this characterized in that a water-soluble pesticide is added to the extrudable aqueous mixture. 409831/1073