JPS5854121B2 - Nogiyouyousoseibutsu Oyobi Hohou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION It is desirable to have agricultural chemicals that act over long periods of time in the field of use, such as insecticides such as herbicides, insecticides, acaricides, ovicides, fungicides or nematode killers. There are many cases.

However, when such compounds are applied to the site of use in pure form or with one of the conventional carriers, they usually become dispersed in the environment, which can only exist for a very short period of time.

Alternatively, if any sustained effect is to be produced, a large quantity of the compound must initially be present, such that it takes a long time to disperse into the surroundings, but this is uneconomical and undesirable for other reasons. .

In British Patent Specification No. 1,394,990 we have prepared agricultural compositions consisting of a particular type of mixture of partially neutralized acidic polymers and agricultural chemicals with sustained release. showed that it is possible.

The specification indicates that neutralization is preferably carried out with a monovalent base such as an alkali metal or ethanolamine, and most preferably with a polyvalent cation such as zinc or copper. There is.

Although these compositions are very satisfactory for many chemicals, they only work satisfactorily under alkaline or neutralizing conditions.

Unfortunately, some agricultural chemicals exhibit very poor stability when exposed to the environmental conditions of their intended use.

This is especially the case under alkaline or neutral conditions.

Stability is indicated by the half-life of a chemical after it has been applied to its intended use, and the short half-life of some chemicals may pose significant problems in their use.

For example, M-(4-chloro-2-methylphenyl)-N
-N dimethylformamidine (commonly known as chlordimeform and sold under the trade name Galecron and Fundal) is a very good ovicidal and acaricide, but it is The disadvantage is that it has a relatively short shelf life.

One reason for the low persistence of chlorodimeform is that this material is highly susceptible to decomposition under neutral or alkaline conditions, which are most often found on plant surfaces.

This substance is very stable at acidic pH values as shown in Table 1 which shows the half-life of chlordimeform in aqueous media at 20° C. at different pH values.

When sprayed on crops, chlordimeform hydrochloride immediately reacts with alkaline dust present on leaves and other surfaces, resulting in hydrolysis.

Another reason for the low persistence of this material is its relatively high vapor pressure (3.5
g), and because of this, it quickly disperses into the atmosphere.

Chlordimeform is a salt-forming chemical, in fact often used as the hydrochloride salt, and it can be appreciated that many other salt-forming agricultural chemicals also have short half-lives for the same reasons as chlordimeform. Dew.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an agricultural product and a process for its production which sustains the release of agricultural chemicals and provides them with a long half-life.

In particular, it is an object of the invention to propose a product and a process for its preparation, in which the agrochemical is a salt-forming agrochemical, in particular a herbicide or an insecticide.

The product according to the invention is a water-soluble or water-dispersible composition of a polymer containing acid groups and a salt-forming agrochemical.

The agrochemical can be any salt-forming herbicidal or insecticidal chemical, but is preferably one that is effective under alkaline conditions, and it is preferably an N-arylamidine, especially one whose aryl groups are Patent Specification No. 964
No. 640 and No. 1039930 and No. 1340600
N which is a phenyl group substituted as described in No.
It is an arylamidine.

Chlordimeform is a preferred agrochemical for use in the present invention.

Other suitable chemicals include guanidine, such as dodecylguanidine, and those described in US Pat. No. 2,867,562; British Patent No. 964.
No. 640 and No. 103993Q and No. 1140965
Phenylformamidine as described in No. 1 and No. 1327936;
Substituted phenylmethyl carbamates such as (4-dimethylamino-3,5-xylylmethylcarbamate) and those described in British Patent Specification No. 925,424; and salt-forming triazines.

An example of a triazine is the herbicide 2-methylthio-4-isopropylamino-6-(3-methoxypropylamino)-8-)riazine.

The polymer must contain acid groups, and usually these acid groups are carboxylic acid groups.

Usually they are present in the polymer as free carboxyl groups.

The polymer may be a homopolymer of monomers containing acid groups, in which case it is generally hydrophilic.

The polymer may also be a copolymer of various monomers, some or all of which contain acid groups.

These monomers are preferably vinyl monomers.

25% by weight or more of monomers that are usually raw materials for polymers,
Preferably 40% by weight or more, most preferably 70% by weight
The above contains acid groups.

Generally 10-100% by weight, more preferably 25-100% by weight
100% by weight, and often 50 to 95% by weight, e.g. 92% by weight of hydrophilic monomers (which are usually all acidic) and 0 to 90% by weight, more preferably 0 to 7% by weight.
It is preferred to use 5% by weight of hydrophobic monomer, and often from 5 to 50%, for example 8% by weight.

The types of monomers and their proportions in these polymers are chosen taking into account the agrochemicals to be used, the location where the compositions are to be applied and the environmental conditions to be expected after their application. .

For example, when they are to be used for processing cotton in dry environments where rain is not expected, the polymer must be sufficiently soluble to ensure that atmospheric moisture will leach the active ingredient from the composition. On the other hand, if it is to be applied in an area where rain can be expected, the composition, or at least the dry coating obtained upon application to the site, will not be washed away by the rain. should be insoluble to a considerable extent.

Therefore, for different combinations of conditions, a variety of polymers are selected over the entire range, from polymers consisting entirely of hydrophilic groups to polymers consisting primarily of hydrophobic groups with some hydrophilic groups. be able to.

Generally, if low water resistance is required the polymer will be made from at least 50% by weight hydrophilic monomers, preferably 70% by weight, while if high water resistance is required the polymer will be made from 20-70% by weight hydrophilic monomers. made from a monomer mixture containing monomers.

However, the ratio of hydrophilic to hydrophobic monomers is not the only means of controlling water resistance and other properties of the salt.

For example, they are also controlled by salt crosslinking, in particular by crosslinking during drying of the salt coating at its intended use.

In this way a water-soluble or water-dispersible composition is applied, which upon drying forms a water-insoluble film or other coating.

Crosslinking can be effected by incorporating into the monomer mixture suitable difunctional monomers, especially those that crosslink only when dry.

Several such difunctional monomers are known, including ethylene glycol dimethacrylate.

However, N-methylolacrylamide is probably the best.

The amount of crosslinking monomer is generally small, for example from 1 to 15% by weight, preferably from 1 to 10% by weight.

Suitable hydrophilic monomers include monomer acids such as acrylic acid, methacrylic acid, crotonic acid, vinyl sulfonic acid, maleic acid, angelic acid, oleic acid or alpha-chloro-acrylic acid or sulfoethyl methacrylate.

Any of these may be used alone as a hydrophilic monomer, or two or more may be used together.

Suitable hydrophobic monomers include alkyl acrylates,
These include alkyl methacrylates, vinyl ethers, acrylonitrile, styrene and vinyl acetate.

If hydrophobic monomers are present, at least a portion of them are 5
It may be plasticizing monomer in proportions by weight of between 20% and preferably about 10%.

Suitable plasticizing monomers are, for example, long chain esters of acrylic or methacrylic acid, such as ethylhexyl acrylate.

Preferred polymers which are particularly suitable for forming salts with chlordimeform or other insecticides, acaricides or ovicides used in arid regions, such as in the case of cotton, contain only hydrophilic groups; It is a copolymer that crosslinks during drying, and an example is a copolymer of acrylic acid and/or methacrylic acid and a small amount of N-methylolacrylamide.

Polymerization of the monomers is carried out by conventional techniques of either bulk, solution, emulsion or dispersion polymerization using catalysts well known in the art.

Preferably they are carried out by emulsion polymerization or solution polymerization.

Other substances to be included before and after polymerization include plasticizers,
Emulsifiers, stabilizers and wetting agents may be mentioned.

Depending on the monomers used, the polymers may be water-soluble or water-dispersible or soluble in common organic solvents such as lower alcohols (optionally mixed with water), acetone or dimethylformamide.

This salt is obtained simply by mixing the acidic polymer and the salt-forming agrochemical, usually in the presence of water and/or an organic solvent.

The ratio of chemical to acidic polymer is generally 1:0.1-1
:10. Preferably the ratio is 1:0.5 to 1:3, most preferably 1 part chemical to 1.2 parts acidic polymer.

Preferably, the polymer contains a commercially available excess of acid groups necessary for complete neutralization of the chemical.

This excess is for example at least 20%, preferably at least 50%.

The composition actually applied to the site to be treated has a concentration of salt formed from the composition of the invention of 0.05 to 5%, preferably 0.1 to 2%, and a concentration of polymer of 0.5%. ~3%
Preferably it is 1 to 3%.

These compositions are suitably made by diluting the solution or emulsion forming the polymer with a suitable amount of water and then adding the agrochemical to the diluted solution or emulsion.

The salt must of course be water-soluble or water-dispersible during application, but it becomes insoluble when dry.

Preferably the salt is film-forming, but this is not essential.

The aqueous solution or dispersion applied to the plant or other area to be treated is applied by standard means, such as by spraying using standard equipment.

Upon drying, a coating, often a continuous film, of the polymer salt is formed on the plant or elsewhere, and this coating has the polymer salt dissolved or mixed therein.

Moisture absorbed from the environment of the coating, for example from plants and/or from the atmosphere, gradually hydrolyzes the polymer salt to liberate the chlordimeform or other agrochemical, however the chemical is still dissolved in the polymer. Therefore, its volatility is quite small.

It is noted that salt formation greatly influences the water solubility of the product even before drying of the resulting coating.

Next, examples will be given of the polymers and salts used in the present invention and their uses.

Example 1 Niacrylic acid solution polymer was obtained using the following composition Methyl methacrylate 2 ethyl hexylaque benzoyl peroxide ethanol 55 l1I 35 f? Related 10g 0.4? 100? The solution is heated to reflux with stirring for 6 hours.

The final content will be 48% solids.

This base can be varied by varying the acid content between 30% and 60% and thus varying the methyl methacrylate or other hydrophobic component.

Example 2 An acrylic acid homopolymer was obtained using the following composition Niacrylic acid 650 v Water 1550 P Isopropanol 600 ? Ammonium persulfate 1.8f? After 1.5 hours of reflux, the polymer solution contains 25% solids.

Example 3 A copolymer of acrylic acid and N-methylolacrylamide was obtained using the following composition: Niacrylic acid
2762N-methylolacrylamide
24 P isofuropanol 300 ?
Water 600 r Ammonium Persulfate 1. After refluxing for 212 hours, the polymer solution contains 25% solids.

Example 4 By a method similar to that in Examples 1 to 3,
Polymer solutions from the following monomers were obtained in each of the solvents listed in the table below.

The ratios here are expressed in % by weight.

The following abbreviations are used in this and the following examples: AA = acrylic acid MAA - methacrylic acid MMA = methyl methacrylate MA = methyl acrylate 2EHA = 2-ethylhexyl acrylate HMA = N
- Methylol acrylamide SEM = Sulfoethyl methacrylate Similarly, some or all of the above hydrophilic monomers, ie, acrylic acid, methacrylic acid and sulfoethyl methacrylate, are combined with crotonic acid, vinyl sulfonic acid, maleic acid, angelic acid, oleic acid and α-chloro- This can be done by replacing monomers such as acrylic acid.

Similarly, some or all of the hydrophobic monomers mentioned above, namely methyl methacrylate, methyl acrylate and 2-ethylhexyl acrylate, can be replaced by other alkyl acrylates and methacrylates, vinyl ethers, acrylonitrile, styrene and vinyl acetate, for example. I can do it.

Example 3 An emulsion polymer was obtained using the following composition: Methyl methacrylate 22.5f Methacrylic acid 12.5f 2-ethylhexyl acrylate 15.0P (Trit
on) X-200*1.8P Sodium Lauryl Sulfate
2.52 water
88.5P* manufactured by Rohm and Haas (Philadelphia) Anionic emulsifier 0.25S' ammonium persulfate is used as the catalyst.

Heat the emulsifier and water mixture to 80°C.

The catalyst is then added and then gradually the monomer mixture is added.

Polymerization is completed at 95°C.

This polymer is diluted with water and when applied to a surface does not dry into a continuous thin film.

Example 6 Various emulsion polymers were obtained by a method similar to Example 5 from mixtures with weight ratios as shown in the following table: Example 7 10P of industrial purity chlordimeform was mixed with 13.6f prepared in Example 2. Add to the solution.

After vigorous stirring a yellow emulsion is obtained.

A thin film made from this emulsion swells with water but does not dissolve.

In contrast, the thin film made only from the solution polymer of Example 2 is water soluble.

Example 8 Add 10i of industrial purity chlordimeform to 12.5r of the copolymer solution made in Example 3.

After vigorous stirring a yellow emulsion is obtained. A thin film made from this emulsion swells with water but does not dissolve.

Crosslinking takes place there. The products of Examples 7 and 8 were tested for their persistence by paper strips.

Equal amounts of polymer-containing and polymer-free active substances are deposited onto a piece of paper and allowed to stand for various periods of time.

The content of active substances was then analyzed.

The results were as shown in Table 2.

The stability of the neutral salts according to Examples 7 and 8 is clearly observed.

In order to use the concentrates of Examples 7 and 8 as a treatment composition, 1 part by weight of the concentrate may be emulsified with 1 to 20 parts by weight of water.

Example 9 A treatment composition was prepared by combining the dispersion or emulsion obtained in Example 1 or any of 4 to 6 with a polymer concentration of 1 to 3% by weight.
By diluting with an appropriate amount of water so that Made.

Example 10 Example 9 using Zectran instead of chlordimeform
method was repeated.

Example 11 The method of Example 9 was repeated using dodecylguanidine in place of chlordimeform.

Example 12 Products according to the invention and British Patent Specification No. 13949
The following two polymers were made for comparison with those described in No. 90.

Polymer A 55% Niacrylic Acid, 45% Methyl Methacrylate Polymer B 90'% Niacrylic Acid, 10% N-methylolacrylamide A mixture of these polymers and chlordimeform EC was spread onto a strip of paper.

Table 3 shows the percent recovery of active ingredient after various times.

Example 13 The products of Examples 5 and 6 were prepared as emulsion polymers and a distinct improvement in in vitro stability was obtained when used with emulsifiable concentrations of chlordimeform (Galecron EC).

For example, when Galecron JEC in water was applied to paper strips, 13% of the active material was recovered after 48 hours.

"When Galecron JEC was applied with Polymer Emulsion M of Example 6, 38% of the active material was recovered after the same time.

Spodoptera littoralis (Spodo) was used as a test specimen.
Polymers of the above type were found to improve the persistence of chlordimeform in plant in vitro tests using eggs of Ptera nittoralis.

For example, when 60 eggs were sprayed with a solution containing 0.1% active ingredient (chlordimeform), 47 eggs hatched after 504 hours, whereas when the same amount of active ingredient was used with 1% emulsion polymer, If there were, none hatched after the same amount of time.

Example 14 The effect of polymers on reducing the volatility of chlordimeform is shown in Table 4.

A strip of paper is impregnated with equal amounts of the active substance derived from chlordimeform and the chlordimeform/polymer salt as in Example 1 prepared to an emulsifiable concentration.

One 40 x 10 crfL paper strip contains only chlordimeform base of 5TI9 and the other contains equal amounts of chlordimeform and polymer.

The results are as follows.

Example 15 In an in vivo test using plants to evaluate the toxic effect on Spodoptera littoralis eggs, the polymer amidine salt shows even more excellent effects as shown in Table 5.

In this test, cotton was sprayed with 0.1% active concentration of chlordimeform EC alone and 0.1% active plus 0.1% of the acidic polymer of Example 1.

Sixty eggs were used for each test.

The eggs were sprayed and placed after the inoculation period.

Count the number of surviving larvae after the appropriate incubation period.

Example 16 Tetranychus
In vitro tests were carried out on eggs of P. urticae.

In this test, 1% chlordimeform E
Various compositions containing C were sprayed on the primary leaves of beanstalks.

At various stages after spraying, 100 females were allowed to lay eggs on the treated leaves for 24 hours.

Then we removed the female and counted the number of eggs.

Eggs are stored for 6 to 7 days (this time is for untreated ☆
☆The eggs were incubated in a greenhouse (enough time for them to hatch).

The test was repeated twice and the average percent mortality was calculated.

The results in Table 6 show how highly durable the salt/polymer compositions according to the invention are.

Claims (1)

[Claims] 1 (a) N-arylamidine, guanidine,
and salt-forming agricultural chemicals selected from phenylformamidine and phenylmethyl carbamate. (b) (i) a polymer consisting of a hydrophilic monomer selected from acrylic acid, methacrylic acid, crotonic acid, vinyl sulfonic acid, maleic acid, chloroacrylic acid, and sulfoethyl methacrylate; and (11) the hydrophilic monomer and an alkyl acrylate. , alkyl methacrylate,
A copolymer with a hydrophobic monomer selected from vinyl ether, acrylonitrile, styrene, and vinyl acetate and a polymer containing acid groups selected from the group in a weight ratio of 1:0.
．． A water-soluble or water-dispersible agricultural composition containing the agricultural chemical in a ratio of 1 to 1:10 and sustaining the release of the agricultural chemical.