JPH02294303A - Production of agricultural chemical-containing beady polymer - Google Patents

Abstract

PURPOSE:To readily obtain the subject polymer, having high safety and useful as a water holding agent, etc., at a low cost by carrying out water-in-oil type reversed phase suspension polymerization of (meth)acrylic acid and salts thereof, etc., using a water-soluble radical polymerization initiator and then subjecting the formed swollen gel together with an agricultural chemical to azeotropic dehydration. CONSTITUTION:An acrylic acid-based monomer consisting essentially of acrylic acid and/or methacrylic acid and alkali metal salts or ammonium salts, together with a water-soluble radical polymerization initiator (e.g. potassium persulfate), is dissolved in water and the resultant solution is then suspended in an organic solvent, such as n-hexane, to carry out polymerization by a water-in-oil type reversed phase suspension polymerization method. The formed swollen gel is then subjected to azeotropic dehydration in the presence of a plant growth regulator functioning also as a germicide (e.g. hydroxyisoxazole) as an agricultural chemical, etc., to afford the objective agricultural chemical-containing beady polymer.

Description

[Detailed description of the invention] [Background of the invention] Industrial application fields> The present invention relates to a method for producing a water retention agent containing an agricultural chemical.

The water retention agent obtained by the production method of the present invention can be mixed with soil as a water retention agent for agriculture, forestry, horticulture, and greening, or mixed with water alone to be used as artificial soil for hydroponic cultivation of plants.

In recent years, superabsorbent resins have been developed for use as water retention agents for agriculture, forestry, horticulture, and greening, and their use reduces water loss due to evaporation and runoff, making it easier to rinse water. Since the water utilization rate increases, the number of times plants need to be watered can be reduced, resulting in labor savings.

In addition, when used as artificial soil for hydroponic cultivation, transparency,
It is known to be a water retaining agent with excellent ornamental properties.

Furthermore, various methods have been proposed in which this super absorbent resin is used simultaneously with agricultural chemicals, and JP-A-57-25383 discloses saponified products of unsaturated dicarboxylic acid monomer-vinyl ester copolymers, etc. Japanese Patent Publication No. 62-42565 discloses a water retention agent for plant growth which is made by mixing a water-absorbing polymer substance with a carrier component and compression molding the mixture. It is stated that it should be used in combination with agricultural chemicals, etc. Furthermore, Japanese Patent Application Laid-Open No. 58-10503 discloses an agrochemical formulation consisting of an agrochemical, a water-absorbing polymer, and a carrier, which is in the form of granules or tablets.
JP-A No. 58-224607 discloses germinated seed rice,
JP-A-60-188003 discloses a method for directly sowing seeds in which a hydrogel, which may be mixed with a germination promoter, is sown in the soil. A seeding method is disclosed.

However, in the above-mentioned mixing of agricultural chemicals and superabsorbent resins, the mixing is done in the presence of water, for example, by causing the superabsorbent resin to absorb water and swell with water that has previously contained agricultural chemicals. It is in a swollen gel state, and not only is it bulky, but it also has poor miscibility with soil, and there are cases where it is necessary to dry the water it contains before use.

Also, in Japanese Patent Application Laid-Open No. 52-82715, Denbun (
A long-acting drug composition comprising a water-absorbing substance containing a hydrophilic salt of a meth)acrylic acid copolymer as a main component, an agricultural chemical, a fragrance, etc. has been disclosed, and its production method includes (1) preparing a water-absorbing substance; and a drug in water or an organic solvent after mixing or kneading, (2) a method of impregnating a water-absorbing substance with a liquid drug by a method such as spraying, (3) during the process of producing a water-absorbing substance, For example, when copolymerizing starch with a water-soluble monomer such as (meth)acrylic acid, a method is mentioned in which copolymerization is carried out in the presence of a drug, but specific examples include (1) Only methods by mixing or kneading are described.

On the other hand, in JP-A No. 52-99979, water in a water-dispersible emulsion of an oil-based physiologically active substance,
A method for producing a hydrogel containing a physiologically active substance that is solidified by reacting with an isocyanate group in a copolymer is disclosed. Furthermore, Japanese Patent Application Laid-open No. 63-265963 discloses a drug-containing polymer in which a water-absorbing bead-like porous polymer contains a fragrance and/or a drug. (2) 0/W
A method is described in which a drug or fragrance is added directly or diluted with a solvent to the internal oil phase when making and polymerizing a /O emulsion, but it is difficult to include a drug or fragrance in order to allow the drug to coexist during these reactions. All of these methods require a large number of auxiliary agents and the reactions are complicated, so it is difficult to say that these methods are attractive in terms of cost or process. Also, JP-A-59
Publication No. 36601 discloses a method for producing a long-lasting preparation for horticulture, in which fertilizers and the like are dispersed and polymerized in a neutralized aqueous solution of ammonium and/or potassium acrylate. Although this method is economically improved compared to the previously described methods, the resulting dry polymer solids require an additional grinding step for practical use, and at least some of them are pulverized during this process. cannot avoid the occurrence of
This could not be said to be an environmentally friendly form.

[Summary of the invention]

Summary> The present inventors have solved the above-mentioned problems and provided a method for producing a dry polymer containing agricultural chemicals that has water retention properties and does not turn into fine powder, extremely easily and at low cost. This is what I am trying to do.

As a result of various studies to solve the above-mentioned problems, the present inventors polymerized acrylic acid monomers by water-in-oil type reversed-phase suspension polymerization, and the resulting swollen gel was subsequently used to treat pesticides. The present invention was achieved based on the discovery that dry bead-like polymers having water-retentive properties and containing agricultural chemicals can be obtained in an extremely convenient manner and at low cost by azeotropic dehydration in the presence of .

That is, the method for producing a bead-shaped polymer containing a pesticide according to the present invention involves initiating water-soluble radical polymerization of an acrylic acid monomer containing acrylic acid and/or methacrylic acid and an alkali metal salt or ammonium salt thereof as a main component. The method is characterized in that it is polymerized by a water-in-oil reverse phase suspension polymerization method in the presence of a pesticide, and the resulting swollen gel is then subjected to azeotropic dehydration in the presence of a pesticide.

Effects> According to the present invention, a water retention agent containing an agricultural chemical can be produced in an extremely convenient manner and at low cost.

The bead-shaped polymer containing agricultural chemicals obtained by the present invention is in a dry state, so it is useful for transportation and other handling, and since there is no fine powder, there is no effect on the human body due to powder flying up. Very few.

(Specific Description of the Invention) Acrylic Acid Monomer The acrylic acid monomer used in the polymerization reaction of the present invention has acrylic acid and/or methacrylic acid and an alkali metal salt or ammonium salt thereof as main components. Preferred specific examples of such acrylic acid monomers include 20% or more of the total carboxyl groups in the standard product,
The main component is preferably 50% or more of which is neutralized with an alkali metal salt or ammonium salt. In this case, if the degree of neutralization is less than 20%, the water absorption performance will be low and the strength of the obtained water absorption gel will be extremely low. The upper limit of the degree of neutralization is about 90%.

As the alkali agent for neutralizing the acid monomer to the alkali metal salt, alkali metal hydroxides, bicarbonates, and the like can be used, but alkali metal hydroxides are preferable.

Specific examples of such alkali metal hydroxides include sodium hydroxide, potassium hydroxide, and lithium hydroxide. Sodium hydroxide is most preferred from the viewpoints of industrial manpower, cost, and safety.

The amount of the acrylic acid monomer used in the present invention is:
The more the better. Specifically, the heptamer concentration after neutralization in water is 20% by weight or more, preferably 30% by weight or more. The higher the heptanomer concentration, the more advantageous it is not only in terms of the yield per unit batch, but also in terms of economics because the dehydration operation after polymerization is easier.

In addition, in the present invention, heptanomers other than the above, such as (a) itaconic acid, maleic acid, fumaric acid, 2-monoacrylamido-2-methylpropanesulfonic acid, 2-acryloylethanesulfonic acid, 2-acryloylbrobanesulfonic acid, and their Salts, (1) Alkyl or alkoxyalkyl esters of dicarboxylic acids such as itaconic acid, maleic acid, and fumaric acid, (8) (meth)acrylamide, (2) vinylsulfonic acid, (v) methyl acrylate, ethyl acrylate. etc., (to)
(Meth) hydroxyethyl acrylate, (meth) hydroxybutyl acrylate, (t)polyethylene glycol 7-(meth)acrylate, N-methylol (meth)
Heptanomers having a copolymerizable double bond in the molecule such as acrylamide, glycidyl (meth)acrylate, and other crosslinking agents include (th) polyethylene glycol di(
Acrylic acid has two or more double bonds in the molecule, such as meth)acrylate, polybropylene glycol di(meth)acrylate, glycerin tri(meth)acrylate, N,N'-methylenebis(meth)acrylamide, etc. or functional groups in acrylic acid monomers such as ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, di- or polyglycidyl ether of aliphatic polyhydric alcohol, etc. It is also possible to use in combination a compound having two or more functional groups that can react with, for example, a carboxyl group during polymerization or during drying after polymerization.

Water-soluble radical polymerization initiator> The water-soluble radical polymerization initiator used in the present invention is well known in the field of polymer chemistry.

Specifically, inorganic or organic peroxides, such as persulfates (ammonium salts, alkali metal salts (especially potassium salts), etc.), hydrogen peroxide, ditertiary butyl peroxide,
Examples include acetyl peroxide. In addition to these peroxides, if a predetermined aqueous solution is obtained, azo compounds and other radical polymerization initiators, such as 2. 2'-azobis(2-amidinobroban) dihydrochloride, 2. 2'-
Azobis(N,N'-dimethyleneisobutyramidine) dihydrochloride, 4,4'-azobis(4-cyanovaleric acid)
etc. can also be used.

Polymerization is initiated by the decomposition of these water-soluble radical polymerization initiators, and in the present invention, the decomposition of the water-soluble radical polymerization initiators is accomplished by not only heating, which is a conventional means, but also decomposition of the water-soluble radical polymerization initiators by chemical substances. It can also be carried out by well-known methods such as promoting the decomposition of . When the polymerization initiator is a peroxide, the decomposition promoting substance is a reducing compound (water-soluble in the present invention) such as an acidic sulfite, ascorbic acid, an amine, etc. for persulfates, and Polymerization initiators consisting of a combination of a peroxide and a reducing compound are well known in the field of polymer chemistry as "redox initiators." Therefore, in the present invention, the term "polymerization initiator" refers to combinations with such decomposition promoting substances, especially redox initiators,
This includes:

The amount of the water-soluble radical polymerization initiator as described above is generally 0.001 to 1
0% by weight, preferably 0.1-2% by weight.

Water-in-oil type reversed-phase suspension polymerization> The polymerization method used in the present invention is a water-in-oil type reversed-phase suspension polymerization, in which an aqueous solution of the monomers and water-soluble radical polymerization initiator as described above undergoes a polymerization reaction. This can be carried out using a stabilized colloid that forms a Uranaka water droplet type dispersion with good stability over time, and an inert solvent.

Specific examples include the following.

(1) A method in which a copolymer of an α-olefin and an α,β monounsaturated polycarboxylic acid anhydride or a derivative thereof is used as a protective colloid, and a hydrocarbon solvent is used in the presence of hydroxyethyl cellulose (Japanese Patent Laid-Open No. 62 (2) Method of using sorbitan fatty acid ester with HLB 3 to 6 as a protective colloid and a petroleum-based aliphatic hydrocarbon solvent (Japanese Patent Publication No. 54-30710) ), (3) A method using an oil-soluble cellulose ester or cellulose ether as a protective colloid and a hydrocarbon solvent (Japanese Unexamined Patent Publication No. 1983-32607), (4) A nonionic type with HLB 6 to 9 as a protective colloid. A method using a hydrocarbon solvent using a surfactant (JP-A-57-167302), (5) using a nonionic surfactant with an HLB of 8 to 12 as a protective colloid, and alicyclic or aliphatic carbonization. Method using hydrogen solvent (Tokuko Sho 6
0-25045), (6) A method using a basic nitrogen-containing polymer as a protective colloid and a hydrocarbon solvent (Japanese Patent Laid-Open No. 57-985)
(7) A method using a carboxyl group-containing polymer as a protective colloid and a hydrocarbon solvent (Japanese Unexamined Patent Publication No. 57-9)
(8) A method using a sucrose fatty acid ester as a protective colloid and a hydrophobic organic solvent (Japanese Patent Application Laid-Open No. 61-436)
(9) As a protective colloid, (A) 50 to 97 mol% of styrene and/or its alkyl-substituted derivative, (B) dialkylaminoalkyl (meth)acrylate and/or Dialkylaminoalkyl (meth)acrylamide 3-5
A method using a hydrophobic organic solvent using a copolymer consisting of 0 mol% and (C) 0 to 30 mol% of an unsaturated monomer copolymerizable with the above (A) and (B) (JP-A-Sho 6 1. -
40309), (10) sorbitan aliphatic ester and/or sucrose aliphatic ester as a protective colloid, and (A) 50 to 97 mol% of styrene and/or its alkyl-substituted derivative;
(B) 3 to 50 mol% of dialkylaminoalkyl (meth)acrylate and/or dialkylaminoalkyl (meth)acrylamide and (C) the above (A) and (B)
A method using a copolymer consisting of 0 to 30 mol % of an unsaturated monomer that can be copolymerized with a hydrophobic organic solvent (JP-A-61-53308), (11) HLB3-3 as a protective colloid. Examples include a method using a mixture of sorbitan aliphatic ester No. 9 and a polyoxyalkylene monoether type nonionic surfactant and a hydrophobic solvent (Japanese Unexamined Patent Publication No. 97301/1983). Among these, in particular, (1) a method in which a copolymer of an α-olefin and an α,β monounsaturated polycarboxylic acid anhydride or a derivative thereof is used as a protective colloid, and a hydrocarbon solvent is used in the presence of hydroxyethyl cellulose. (JP-A-62-95307, JP-A-62-95308
Publications) are mentioned as suitable polymerization methods.

Pesticides> Pesticides used in the production method of the present invention are those that are applied to agricultural crops (including trees) or agricultural and forestry crops to supply necessary nutrients to them, or to promote or suppress their growth. or agents for controlling plants and animals such as weeds, fungi, nematodes, and rats that harm them, such as fertilizers, insecticides, fungicides, herbicides, plant growth regulators, nematicides, rodenticides, and repellents. This refers to drugs, etc. These can be any substance as long as it can be uniformly dispersed in the reaction solution after polymerization, such as (a) nitrogenous fertilizers (urea, ammonium sulfate, ammonium nitrate, ammonium phosphate, ammonium chloride, Fertilizers such as sodium nitrate, calcium nitrate, potassium nitrate, etc.), phosphoric acid fertilizers (potassium phosphate, calcium phosphate, etc.), potassium fertilizers (potassium chloride, potassium sulfate, etc.), organic phosphorus (CY)
AP, MEP, JECP, diazinon, viridafention, marathon, dimethoate, isothioate, D
MTP, DDVPS EPN, ESP, etc.), carbamate type (NAC, MTMCSBPMC, MPMC, virimicarb, etc.), chlorine type (chlordane, kelsene, etc.), natural type (pyrethrin, rotenone, etc.), biresteroid type insecticides, ) Sulfur-based (maneb, polycarbamate,
(thiram, etc.), organochlorine (TPN, fusaride, etc.), organophosphorus (IBP%EDDP, etc.), hydroxyisoxazole, PCNB, cabtan, phenadione oxide, CNA, anilazine, thiophanate methyl, imbrothiolane, fluorimide, etc. disinfectants. , (2) triazine type (simazine, atrazine, etc.), dinitroaniline type (triflualine, etc.), phenoxy type (nabroanilide, 2.4-D, 2.4-PA, etc.), acid amide type (butachlor, etc.), diphenyl Herbicides such as ether type (bifenox, chromethoxynil, etc.), urea type (diuron, methyldaimeron, DCMU, etc.), aryloxybrobionic acid type (fluazifop, etc.), carbamate type (benthiocarb, TPC, etc.), (e)indole acetic acid , indoleacetic acid, choline chloride, pendylaminopurine, 1-naphthylacetamide, etc., plant growth regulators, (f) EDB, EDC, DCIP, etc. nematicides, (g) coumarin series, sodium monofluoroacetate, etc. Examples include rodenticides, repellents such as (h) β-naphthol, creosote, diethyltoluamide, calcium hybochloride, and the like, or a mixture of two or more thereof.

Considering the treatment of the inert solvent used in the polymerization after the production of bead-like polymers containing these pesticides, the pesticides targeted by the present invention can be The higher the concentration (medium concentration), the more preferable it is. Such pesticides are generally water-soluble.

Specific Manufacturing Method> An example of a specific embodiment of the manufacturing method of the present invention is as follows. That is, acrylic acid and/or methacrylic acid is neutralized in advance to form an aqueous alkali metal salt solution or ammonium salt aqueous solution, and a crosslinking agent, a water-soluble radical polymerization initiator, etc. are added to this to obtain an aqueous acrylic acid monomer solution. .

Separately, a protective colloid is added and suspended in an inert solvent, and an inert gas such as nitrogen is introduced to perform deaeration. The above aqueous acrylic acid monomer solution is added to this and heated to a predetermined temperature to polymerize. After polymerization, the polymer is in a wet state and exists as a slurry in an inert solvent.

Next, water in the slurry solution is azeotropically dehydrated while adding the pesticide directly or diluted with a solvent to the slurry solution. The polymer obtained as described above consists of bead-like particles and can be easily separated from the inert solvent by decantation or the like, and can be further dried if necessary. On the other hand, inert solvents do not require any particular purification operations such as distillation, and can be reused in a state containing protective colloids and some pesticides.

〔Example〕

The following examples and efficacy tests are intended to further illustrate the present invention.

In addition, the pure water absorption capacity was calculated according to the following method.

Approximately 1 g of polymer and approximately 1 gram of pure water in a 1000 cc beaker
Weigh and add 000g of each, mix and add about 5
It was left to stand for a while to allow sufficient swelling. Next, the weight of the swollen gel was measured after thoroughly draining with a 28 mesh sieve.
Pure water absorption capacity was calculated according to the following formula.

(r/tr resin) Charged polymer weight (g) Example 1 In a five-neck flat bottom flask with a capacity of 1000 cc, equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas inlet tube,
450 g of n-hexane and 9.0 g of α-olefin-maleic anhydride copolymer (manufactured by Mitsubishi Kasei Corporation, trade name "Diakarna 30", molecular weight approximately 10,000) were added,
Nitrogen gas was introduced while stirring at room temperature.

Separately, in a conical flask with a volume of 300 cc, 75.0 g of acrylic acid was cooled from the outside, and 2 ml of water was added to it in advance.
An alkaline aqueous solution prepared from 7.9 g and 123 g of 25.0% sodium hydroxide was added to neutralize 77.5% of the carboxyl groups.

Next, 0.150 g of N,N'-methylenebisacrylamide and hydroxyethyl cellulose (degree of etherification -1, number of moles of EO added -2) were added to this as a crosslinking agent.2.
25 g and 0.25 g of potassium persulfate as a water-soluble radical polymerization initiator were added and dissolved.

Add this 300cc to the contents of the five-necked flat-bottomed flask.
The contents of the conical flask were added, and while stirring, the temperature was raised at a rate of 1°C/min to carry out polymerization at 62 to 65°C for about 1 hour.

Next, 3.0 g of hydroxyisoxazole and 37.5 g of water as a plant growth regulator and fungicide. Azeotropic dehydration was carried out while adding a mixed solution of the mixture dropwise from the dropping funnel until the internal temperature exceeded 68°C.

After azeotropic dehydration, when stirring is stopped, the bead-like polymer particles settle to the bottom of the flask and are decanted by decantation.
Can be easily separated from the hexane phase, 109.2g
of polymer was obtained. The obtained polymer was further dried at 60°C under reduced pressure. Sample (1), a yellow transparent bead-like polymer of Or, was obtained.

The pure water absorption amount of sample (1) was 229 (g/g resin).

In addition, as a result of repeatedly extracting sample (1) with water and quantifying the amount of hydroxyisoxazole in the filtrate by high performance liquid chromatography, it was found that 23.5 mg of hydroxyisoxazole was contained in Ig of sample (1). It became clear that

Example 2 In Example 1, benzylaminobulin 1. was used as a plant growth regulator instead of hydroxyisoxazole. oog
Polymerization, dehydration, and drying were carried out in the same manner except that a mixed solution of 4.45 g of IN sodium hydroxide aqueous solution was used to obtain 101.9 g of a colorless transparent bead-shaped polymer sample (2
) was obtained.

The pure water absorption amount of sample (2) was 256 (g/g resin).

As a result of analyzing the amount of benzylaminopurine in sample (2) in the same manner as in Example 1, it was found that 7. 42 (ng/g per sample) was found to be present.

Example 3 In Example 1, indoleacetic acid 6. was used as a plant growth regulator instead of hydroxyisoxazole. oog and IN
Sodium hydroxide aqueous solution 41.03. Polymerization, dehydration, and drying were carried out in the same manner except that a mixed solution of
．． 0 g of white bead-like polymer, sample (3), was obtained.

The pure water absorption amount of sample (3) was 265 (+r/sr resin).

As a result of analyzing the amount of indole acetic acid in sample (3) in the same manner as in Example 1, it was revealed that the amount was 45.5 (1 g/g-sample).

Example 4 In Example 1, 2.51 g of choline chloride and 9.9 g of water were used as plant growth regulators instead of hydroxyisoxazole.
Polymerization, dehydration, and drying were carried out in the same manner except that 7 g of the mixed solution was used to obtain 108.4 g of a colorless and transparent bead-like polymer, Sample (4).

The pure water absorption amount of sample (4) was 227 (g/g resin).

The amount of choline chloride in sample (4) was analyzed in the same manner as in Example 1 except that a nitrogen analyzer was used, and the result was 22. 1
(ag/g one sample) It became clear that it was contained.

Effect test Samples (1) to (4) and bead-shaped polymers (comparative sample) produced in the same manner as in Example 1 except that no pesticides were added were mixed in dry sandy loam at a concentration of 0.1% by weight. Then, a plastic pot measuring 40 cm long, 30 cm wide, and 20 cII+ high was filled to a thickness of 15 cm. After that, water was supplied from the bottom water absorption hole to bring it to a saturated state, and then the koala grass was transplanted. Irrigation was discontinued after 7 days, and the plants were left to rainwater from then on.

After 50 days and 90 days, three plants were collected from each area.
Tables 1 and 2 show the results of disassembling the plant into upright stems, stolons, and root systems, and determining the amount of elongation and fresh weight for each part. For erect stems and root systems, the total length of the three longest stems and all fresh weights, and for stolons, the total length and their fresh weight.

The test results are shown as a percentage of the additive-free group.

Table 1 (after 50 days) From the ml table and Table 2, sample (l) (hydroxyisoxazole), sample (2) (benzylaminopurine), sample (3) (indole acetic acid), and sample (4) ( Bead-shaped polymers containing pesticides such as choline chloride (choline chloride) have a better effect on the growth of grasshoppers than bead-shaped polymers without additives or without pesticides in comparison samples, although there are differences in degree. It became clear.

Table 2 (after 90 days)

Claims (1)

[Claims] Polymerization of acrylic acid monomers containing acrylic acid and/or methacrylic acid and their alkali metal salts or ammonium salts as main components by a water-in-oil reverse phase suspension polymerization method in the presence of a water-soluble radical polymerization initiator. 1. A method for producing a bead-like polymer containing a pesticide, the method comprising: azeotropically dehydrating the resulting swollen gel in the presence of the pesticide.