Pesticide microcapsule suspending agent and preparation method thereof

Abstract

The invention relates to the technical field of pesticide preparations, and discloses a pesticide microcapsule suspending agent and a preparation method thereof. The capsule wall material of the pesticide microcapsule suspending agent is furfural resin. The pesticide microcapsule suspending agent is prepared by an interfacial polymerization method. The pesticide microcapsule suspending agent provided by the invention also has higher encapsulation efficiency after being stored, excellent heat storage stability and cold storage stability, and good suspension rate and flowability; the pesticide preparation is prepared by utilizing a microencapsulation technology, the preparation method is simple, the effective components are coated on the furfural resin so that the furfural resin is slowly released, the utilization efficiency of the medicine is improved, and the release period of the medicine is controlled and prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of pesticide preparations, and in particular to a pesticide microcapsule suspension and a preparation method thereof. Background Art

[0002] Nematodes are the most abundant multicellular animals on Earth, and they can be found wherever there is water. Among them, plant parasitic nematodes account for 10%, which harms plant growth through parasitism and is one of the important factors leading to major economic losses in agriculture and forestry. In field diagnosis, soil nematode diseases can easily be confused with element deficiencies, root cancer, and clubroot, leading to misdiagnosis or untimely prevention and control. In addition, the root wounds caused by nematode feeding provide opportunities for the occurrence of soil-borne diseases such as bacterial wilt, damping-off, root rot, damping-off, and ulcers, resulting in complex infections and further increasing the difficulty of prevention and control.

[0003] Thiazole is an organophosphorus nematicide. Its main mechanism of action is to inhibit the synthesis of acetylcholinesterase of root-knot nematodes. It is systemic and can be used to control various root-knot nematodes. Since Thiazole was developed and produced by Ishihara in Japan in 1991, it has been registered in many countries and regions such as Europe and the United States. Thiazole has become an important product for controlling soil nematodes with its good effect and high cost performance. It is expected to remain the main variety for soil nematode control in the next few years. The formulations include emulsifiable concentrates, water emulsions, microemulsions, granules, microcapsule suspensions, and soluble solutions. The compounding object is mainly avermectin.

[0004] The appearance of pure thiazole phosphine is light yellow liquid. Bp198℃ / 66.66Pa, vapor pressure5.6×10 -4 Pa (25°C), solubility in water is 9.85g / L (0.87%), and distribution coefficient is 1.75. However, the common original drug in China is basically 90% in content, and its solubility in water is higher.

[0005] Microcapsule suspension refers to a pesticide formulation that uses natural or synthetic polymer materials to form a core-shell structure micro-container, encapsulates the pesticide, and suspends it in water. Existing thiazole phosphine microcapsule suspensions use urea-formaldehyde resin, polyurea / polyurethane, etc. as wall materials, with low encapsulation efficiency after storage and complex preparation process. Summary of the invention

[0006] The purpose of the present invention is to overcome the problems existing in the prior art and to provide a pesticide microcapsule suspension with a simple preparation method and a high encapsulation rate and a preparation method thereof.

[0007] In order to achieve the above object, the present invention provides a pesticide microcapsule suspension in a first aspect, wherein the capsule wall material of the pesticide microcapsule suspension is furfural resin.

[0008] The second aspect of the present invention provides a method for preparing the pesticide microcapsule suspension according to the first aspect, wherein the pesticide microcapsule suspension is prepared by interfacial polymerization.

[0009] Through the above technical solution, the beneficial technical effects achieved by the present invention are as follows:

[0010] (1) The pesticide microcapsule suspension provided by the present invention has a high encapsulation rate after storage, and has excellent hot storage stability and cold storage stability, and has good suspension rate and fluidity;

[0011] (2) The present invention utilizes microencapsulation technology to prepare pesticide formulations, which has a simple preparation method. The active ingredients are coated in furfural resin to allow them to be slowly released, thereby improving drug utilization efficiency, controlling and extending the drug release cycle, etc. DETAILED DESCRIPTION

[0012] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0013] A first aspect of the present invention provides a pesticide microcapsule suspension, wherein the capsule wall material of the pesticide microcapsule suspension is furfural resin.

[0014] When urea-formaldehyde resin is used as the capsule wall material, the preparation process needs to first use formaldehyde and urea to adjust the pH to alkaline to prepare the prepolymer, and then adjust the acid to produce a polycondensation reaction to form microcapsules, and then adjust the pH to neutral to stabilize the system, which is complicated. When polyurea / polyurethane is used as the capsule wall material, the microcapsule suspension is prepared by interfacial polymerization of isocyanate and polyamine / polyol. The reaction process of isocyanate and polyamine is violent and continuous, and isocyanate also reacts with water to produce carbon dioxide, and the reaction process is prone to explosion. In addition, the low encapsulation rate after storage cannot meet the use requirements.

[0015] Furfural resin refers to a furan resin polymer obtained by polycondensation or copolymerization with furfuryl alcohol or furfural as the main raw material. The inventors of the present invention surprisingly found in the process of preparing microcapsule suspension that using furfural resin as capsule wall material can obtain a higher encapsulation rate and the preparation process is simple.

[0016] In some embodiments of the present invention, the active ingredient of the core of the pesticide microcapsule suspension is selected from at least one of thiazolyl, metalaxyl-M and pirimiphos-methyl, preferably thiazolyl. The thiazolyl microcapsule suspension prepared by the present invention can be used to control root-knot nematodes in crops such as tomatoes, cucumbers, and ginger.

[0017] In some embodiments of the present invention, the mass fraction of the active ingredient in the core of the pesticide microcapsule suspension is 10-45%, preferably 20-40%, and more preferably 30%.

[0018] In some embodiments of the present invention, in the pesticide microcapsule suspension, the weight ratio of the capsule core material to the capsule wall material is 1:0.1-0.2. The capsule core material refers to the capsule core active ingredient and the solvent.

[0019] The second aspect of the present invention provides a method for preparing the pesticide microcapsule suspension according to the first aspect, wherein the pesticide microcapsule suspension is prepared by interfacial polymerization.

[0020] In some embodiments of the invention, the method comprises the following steps:

[0021] (1) mixing the capsule core active ingredient, the solvent and the furfural resin to obtain a first mixed material;

[0022] (2) mixing water, defoaming agent and emulsifier for a second time to obtain a second mixed material;

[0023] (3) adding the first mixed material to the second mixed material and shearing to form an O / W emulsion to obtain a third mixed material;

[0024] (4) heating the third mixed material to 50-70° C., adding an acid catalyst to solidify the furfural resin, then keeping the temperature at 50-70° C. for 2-4 hours, and cooling the temperature to 25-30° C.;

[0025] (5) adding other adjuvants to the material obtained in step (4) to obtain the pesticide microcapsule suspension.

[0026] The preparation method of the pesticide microcapsule suspension provided by the present invention is relatively simple, and the furfural resin curing process only requires acid as a catalyst, and the furfural resin is cured to form a stable capsule wall material after being kept at 50-70°C for 2-4 hours. The prepared pesticide microcapsule suspension has a high encapsulation rate and good stability, and the furfural resin has a wide source, such as agricultural and sideline products such as corn cobs, and is a renewable raw material.

[0027] In some embodiments of the present invention, the solvent is selected from at least one of xylene, 150# solvent oil, 100# solvent oil, 200# solvent oil, ethyl acetate, cyclohexanone, sec-butyl acetate, dimethyl carbonate, soybean oil, methyl oleate and mineral oil.

[0028] In some embodiments of the present invention, the defoaming agent is selected from at least one of silicone, polyether-modified silicone and isooctyl alcohol.

[0029] In some embodiments of the present invention, the emulsifier is selected from at least one of 600# phosphate ester, Nongru 500#, Nongru 400#, styrene polyoxyethylene ether ammonium sulfate, Nongru BY series, alkyl diphenyl ether disulfonic acid magnesium salt, triethanolamine salt, Nongru 700#, Ningru 36#, Nongru 1600#, ethylene oxide-propylene oxide block copolymer, Nongru OP series, Nongru 33#, Span series, Tween series and AEO series.

[0030] In some embodiments of the present invention, the acid catalyst is selected from at least one of acetic acid, phosphoric acid, lactic acid, citric acid, hydrochloric acid and sulfuric acid.

[0031] In some embodiments of the present invention, the other auxiliary agent is selected from at least one of a dispersant, a thickener, a preservative and an antifreeze agent.

[0032] In some embodiments of the present invention, the dispersant is selected from at least one of styrylphenyl polyoxyethylene ether, nonylphenol polyoxyethylene ether, sodium dodecyl sulfate, sodium methylene bisnaphthalene sulfonate, sodium 1-methylnaphthalene sulfonate formaldehyde condensate, benzylnaphthalene sulfonic acid formaldehyde condensate, sodium dodecylbenzene sulfonate, sodium lignin sulfonate, desugared sodium lignin sulfonate, desugared condensed sodium lignin sulfonate, carboxylate structure polymer dispersant, sodium succinate sulfonate, opening powder, calcium dodecylbenzene sulfonate, fatty alcohol polyoxyethylene ether, polycarboxylate and polyoxyethylene polyoxypropylene block copolymer.

[0033] In some embodiments of the present invention, the thickener is selected from at least one of organic bentonite, white carbon black, magnesium aluminum silicate, polyvinyl alcohol, polyethylene glycol, xanthan gum, guar gum and sodium carboxymethyl cellulose.

[0034] In some embodiments of the present invention, the preservative is selected from at least one of kasone, sodium benzoate, potassium sorbate, methyl paraben, sodium diacetate, calcium propionate and sodium lactate.

[0035] In some embodiments of the present invention, the antifreeze agent is selected from at least one of ethylene glycol, glycerol, 1,2-propylene glycol, sorbitol and urea.

[0036] The pesticide microcapsule suspension prepared by the present invention has the following advantages:

[0037] 1. By controlling the release of active ingredients of pesticides (such as thiazolyl) through microencapsulation, the control period of pests can be extended, the effective utilization rate can be improved, and the control effect can be consolidated.

[0038] 2. The prepared pesticide preparation is not easily damaged by rain or degraded by light, and can also effectively control groundwater pollution and reduce the impact on the environment.

[0039] 3. It has the characteristics of high efficiency, low toxicity, low residue and environmental friendliness, and is highly safe for humans and animals. It is a good green and environmentally friendly pesticide and is in line with the development direction of the pesticide industry.

[0040] The present invention will be described in detail below through examples.

[0041] In the following examples and comparative examples, if no specific conditions are specified, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used, if no manufacturer is specified, are all conventional products that can be obtained through commercial channels.

[0042] Sources:

[0043] Thiazofosate technical: Hebei Weiyuan Biochemical Co., Ltd., 95%.

[0044] Furfural resin: Guangdong Wengjiang Chemical Reagent Co., Ltd., product number PB06896.

[0045] Ethylene oxide-propylene oxide block copolymer: Croda, Atlas TM G-5002L.

[0046] Polycarboxylate: Croda, Atlox 4913.

[0047] Example 1

[0048] This example is used to illustrate the preparation of 10% thiazolyl microcapsule suspension.

[0049] (1) 11.2 g of thiazole thiazolyl technical, 30 g of 200# solvent oil and 8 g of furfural resin were mixed to obtain an oil phase;

[0050] (2) 38.2 g of water, 2 g of ethylene oxide-propylene oxide block copolymer and 0.2 g of silicone defoamer were mixed to obtain an aqueous phase;

[0051] (3) adding the oil phase into the water phase to obtain a stable O / W system by shearing, and transferring the system into a three-necked flask and heating it to 60° C.;

[0052] (4) Weigh 1 g of glacial acetic acid and 2 g of water, mix well, slowly drip into a three-necked flask, and keep warm for 2 h. After the heat preservation, cool to 30 °C;

[0053] (5) 5 g of propylene glycol, 2 g of polycarboxylate, 0.2 g of xanthan gum and 0.2 g of kason were uniformly mixed and added into a three-necked flask to obtain a 10% thiazolyl microcapsule suspension.

[0054] Example 2

[0055] This example is used to illustrate the preparation of 30% thiazolyl microcapsule suspension.

[0056] (1) 34 g of thiazole original drug, 10 g of 200# solvent oil and 8 g of furfural resin were mixed to obtain an oil phase;

[0057] (2) 35.4 g of water, 2 g of ethylene oxide-propylene oxide block copolymer and 0.2 g of silicone defoamer were mixed to obtain an aqueous phase;

[0058] (3) adding the oil phase into the water phase to obtain a stable O / W system by shearing, and transferring the system into a three-necked flask and heating it to 60° C.;

[0059] (4) Weigh 1 g of glacial acetic acid and 2 g of water, mix well, slowly drip into a three-necked flask, and keep warm for 2 h. After the heat preservation, cool to 30 °C;

[0060] (5) 5 g of propylene glycol, 2 g of sodium lignin sulfonate, 0.2 g of xanthan gum and 0.2 g of kason were uniformly mixed and added into a three-necked flask to obtain a 30% thiazolyl microcapsule suspension.

[0061] Example 3

[0062] This example is used to illustrate the preparation of 45% thiazolyl microcapsule suspension.

[0063] (1) 50 g of thiazolyl technical, 2 g of 150# solvent oil and 10 g of furfural resin were mixed to obtain an oil phase;

[0064] (2) 25.4 g of water, 2 g of ethylene oxide-propylene oxide block copolymer and 0.2 g of silicone defoamer were mixed to obtain an aqueous phase;

[0065] (3) adding the oil phase into the water phase to obtain a stable O / W system by shearing, and transferring the system into a three-necked flask and heating it to 60° C.;

[0066] (4) Weigh 1 g of glacial acetic acid and 2 g of water, mix well, slowly drip into a three-necked flask, and keep warm for 2 h. After the heat preservation, cool to 30 °C;

[0067] (5) 5 g of propylene glycol, 2 g of sodium lignin sulfonate, 0.2 g of xanthan gum and 0.2 g of kason were uniformly mixed and added into a three-necked flask to obtain a 45% thiazolyl microcapsule suspension.

[0068] Comparative Example 1

[0069] This comparative example is used to illustrate the preparation of 30% thiazolyl microcapsule suspension using urea-formaldehyde resin as capsule wall material.

[0070] (1) Add 8g urea and 16g formaldehyde to a three-necked flask equipped with a stirring device, then add 20g water, and adjust the pH value to about 8-9 with sodium hydroxide solution. Raise the temperature to 70-80°C, react for 1h to obtain urea-formaldehyde resin prepolymer, and cool to 35°C for use;

[0071] (2) Dissolve 34 g of thiazolyl oxychloride in 10 g of 200# solvent oil, add 2 g of calcium dodecyl sulfonate and 2 g of By125, and stir to obtain an oil phase;

[0072] (3) adding the prepared oil phase to the urea-formaldehyde resin prepolymer at a rate of 600 rpm to form a stable O / W system;

[0073] (4) adding 4% (mass percentage) acetic acid in batches within 60 minutes to adjust the pH value to 2.5 to cause a polycondensation reaction; gradually raising the temperature to 40-60° C. to solidify the capsule wall;

[0074] (5) After curing for 3 hours, cool to room temperature and add triethanolamine to adjust the pH value to 7.0;

[0075] (6) Add 2 g of block polyether, 0.2 g of kason, 0.1 g of xanthan gum and 5 g of ethylene glycol, and make up to 100 g with water to obtain a 30% thiazolyl microcapsule suspension.

[0076] Comparative Example 2

[0077] This comparative example is used to illustrate the preparation of 30% thiazolyl microcapsule suspension using polyurea as the capsule wall material.

[0078] (1) Weigh 34 g of thiazolyl technical and dissolve it in 10 g of methyl oleate, weigh 3 g of TDI and add it and stir evenly to obtain an oil phase;

[0079] (2) Weigh 2 g of block polyether and 2 g of sodium lignin sulfonate and dissolve them in water to obtain an aqueous phase;

[0080] (3) The oil phase was slowly added to the water phase while shearing at 6500 rpm for 10 min to obtain a stable O / W dispersion and transferred to a three-necked flask;

[0081] (4) Weigh 5 g of water and 0.5 g of triethylenetetramine and stir them evenly. Then add the solution into a three-necked flask at a speed of 400 rpm.

[0082] (5) placing the three-necked flask in a 60°C water bath and stirring and heating for 3 h to perform interfacial polymerization, and cooling the microcapsule dispersion system to room temperature;

[0083] (6) Weigh 5 g of ethylene glycol, 2 g of polycarboxylate, 0.1 g of xanthan gum and 0.2 g of kasonite, mix well, add to a three-necked flask and stir for 30 min to obtain a 30% thiazolyl microcapsule suspension.

[0084] Test Example 1

[0085] The microcapsule suspensions prepared in Examples 1-3 and Comparative Examples 1-2 were subjected to performance tests:

[0086] Thermal storage stability test: The thiazolyl microcapsule suspension was placed in a container, sealed and placed in a constant temperature oven at (54±2)°C. After standing for 14 days, it was taken out, the fluidity was observed, and the suspension rate and encapsulation rate were tested.

[0087] Cold storage stability test: Put the thiazolyl microcapsule suspension into a container, seal it and place it in a low-temperature stability tester at (0±2)℃. After standing for 7 days, take it out, observe the fluidity and test the suspension rate and encapsulation rate.

[0088] Among them, according to GB / T 14825-2006 standard, the suspension rate of microcapsule suspension is determined;

[0089] The encapsulation efficiency was calculated as follows:

[0090] 1. Preparation of standard solution

[0091] Weigh 0.025 g (accurate to 0.00001 g) of thiazole standard into a 50 mL volumetric flask and dissolve it to volume with the mobile phase.

[0092] 2. Indicators of free solution

[0093] Weigh about 0.8g of the sample (accurate to 0.00001g), place it in a 60mL clean wide-mouth glass bottle, accurately add 6mL of water, and gently shake to disperse the sample completely; then add 50mL of ethyl acetate, cover the bottle cap, and place it on a horizontal rotating device, set the bottle speed to 70±10rpm, and start timing at the same time. After 5min±10s, place it vertically on a horizontal table, remove 1mL of the clear liquid, filter it, and set aside.

[0094] 3. Free content detection by liquid chromatography

[0095] 4. Encapsulation rate = (total content - free content) * 100%

[0096] Regarding liquidity, the following classification is made:

[0097] Level 1: excellent fluidity, no stratification or agglomeration;

[0098] Level 2: The fluidity is basically acceptable, with a small amount of stratification and agglomeration;

[0099] Level 3: Viscosity increases, with a lot of stratification and agglomeration.

[0100] The above test results are shown in Table 1.

[0101] Table 1

[0102]

[0103]

[0104] It can be seen from the results in Table 1 that the microcapsule suspension prepared by the present invention using furfural resin as the capsule wall material through a simple interfacial polymerization method has significantly excellent encapsulation efficiency, suspension rate and fluidity after storage under different conditions, and has good stability.

[0105] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A pesticide microcapsule suspension, characterized in that: The capsule wall material of the pesticide microcapsule suspension is furfural resin.

2. The pesticide microcapsule suspension according to claim 1, wherein The active ingredient of the capsule core of the pesticide microcapsule suspension is selected from at least one of thiathiazolyl, metalaxyl-M and pirimiphos-methyl, preferably thiathiazolyl.

3. The pesticide microcapsule suspension according to claim 1 or 2, wherein: The mass fraction of the active ingredient in the capsule core of the pesticide microcapsule suspension is 10-45%, preferably 20-40%, and more preferably 30%.

4. The pesticide microcapsule suspension according to any one of claims 1 to 3, wherein In the pesticide microcapsule suspension, the weight ratio of capsule core material to capsule wall material is 1:0.1-0.

2.

5. A method for preparing a pesticide microcapsule suspension according to any one of claims 1 to 4, characterized in that: The pesticide microcapsule suspension is prepared by interfacial polymerization.

6. The method according to claim 5, wherein: The method comprises the following steps: (1) mixing the capsule core active ingredient, the solvent and the furfural resin to obtain a first mixed material; (2) mixing water, defoaming agent and emulsifier for a second time to obtain a second mixed material; (3) adding the first mixed material to the second mixed material and shearing to form an O / W emulsion to obtain a third mixed material; (4) heating the third mixed material to 50-70° C., adding an acid catalyst to solidify the furfural resin, then keeping the temperature at 50-70° C. for 2-4 hours, and cooling the temperature to 25-30° C.; (5) adding other adjuvants to the material obtained in step (4) to obtain the pesticide microcapsule suspension.

7. The method according to claim 6, wherein: The solvent is selected from at least one of xylene, 150# solvent oil, 100# solvent oil, 200# solvent oil, ethyl acetate, cyclohexanone, sec-butyl acetate, dimethyl carbonate, soybean oil, methyl oleate and mineral oil.

8. The method according to claim 6 or 7, wherein: The defoaming agent is selected from at least one of silicone, polyether-modified silicone and isooctyl alcohol; Preferably, the emulsifier is selected from at least one of 600# phosphate ester, Nongru 500#, Nongru 400#, styrene polyoxyethylene ether ammonium sulfate, Nongru BY series, alkyl diphenyl ether disulfonic acid magnesium salt, triethanolamine salt, Nongru 700#, Ningru 36#, Nongru 1600#, ethylene oxide-propylene oxide block copolymer, Nongru OP series, Nongru 33#, Span series, Tween series and AEO series.

9. The method according to any one of claims 6 to 8, wherein: The acid catalyst is selected from at least one of acetic acid, phosphoric acid, lactic acid, citric acid, hydrochloric acid and sulfuric acid.

10. The method according to any one of claims 6 to 9, wherein: The other auxiliary agent is selected from at least one of a dispersant, a thickener, a preservative and an antifreeze agent; Preferably, the dispersant is selected from at least one of styrylphenyl polyoxyethylene ether, nonylphenol polyoxyethylene ether, sodium dodecyl sulfate, sodium methylene bisnaphthalene sulfonate, sodium 1-methylnaphthalene sulfonate formaldehyde condensate, benzylnaphthalene sulfonic acid formaldehyde condensate, sodium dodecylbenzene sulfonate, sodium lignin sulfonate, desugared sodium lignin sulfonate, desugared condensed sodium lignin sulfonate, carboxylate structure polymer dispersant, sodium succinate sulfonate, pull-open powder, calcium dodecylbenzene sulfonate, fatty alcohol polyoxyethylene ether, polycarboxylate and polyoxyethylene polyoxypropylene block copolymer; Preferably, the thickener is selected from at least one of organic bentonite, white carbon black, magnesium aluminum silicate, polyvinyl alcohol, polyethylene glycol, xanthan gum, guar gum and sodium carboxymethyl cellulose; Preferably, the preservative is selected from at least one of kasone, sodium benzoate, potassium sorbate, methyl paraben, sodium diacetate, calcium propionate and sodium lactate; Preferably, the antifreeze agent is selected from at least one of ethylene glycol, glycerol, 1,2-propylene glycol, sorbitol and urea.

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